documentation: Add documentation for RCU's major data structures

This commit adds documentation for RCU's major data structures,
including rcu_state, rcu_node, rcu_data, rcu_dynticks, and rcu_head.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

12 files changed, 8291 insertions, 0 deletions

diff --git a/Documentation/RCU/Design/Data-Structures/BigTreeClassicRCU.svg b/Documentation/RCU/Design/Data-Structures/BigTreeClassicRCU.svg
new file mode 100644
index 000000000000..727e270b11e4
--- /dev/null
+++ b/Documentation/RCU/Design/Data-Structures/BigTreeClassicRCU.svg
@@ -0,0 +1,474 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!-- Creator: fig2dev Version 3.2 Patchlevel 5e -->
+
+<!-- CreationDate: Wed Dec  9 17:28:20 2015 -->
+
+<!-- Magnification: 3.000 -->
+
+<svg
+   xmlns:dc="http://purl.org/dc/elements/1.1/"
+   xmlns:cc="http://creativecommons.org/ns#"
+   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+   xmlns:svg="http://www.w3.org/2000/svg"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
+   width="9.1in"
+   height="8.9in"
+   viewBox="-66 -66 10932 10707"
+   id="svg2"
+   version="1.1"
+   inkscape:version="0.48.4 r9939"
+   sodipodi:docname="BigTreeClassicRCU.fig">
+  <metadata
+     id="metadata106">
+    <rdf:RDF>
+      <cc:Work
+         rdf:about="">
+        <dc:format>image/svg+xml</dc:format>
+        <dc:type
+           rdf:resource="http://purl.org/dc/dcmitype/StillImage" />
+        <dc:title></dc:title>
+      </cc:Work>
+    </rdf:RDF>
+  </metadata>
+  <defs
+     id="defs104">
+    <marker
+       inkscape:stockid="Arrow1Mend"
+       orient="auto"
+       refY="0.0"
+       refX="0.0"
+       id="Arrow1Mend"
+       style="overflow:visible;">
+      <path
+         id="path3864"
+         d="M 0.0,0.0 L 5.0,-5.0 L -12.5,0.0 L 5.0,5.0 L 0.0,0.0 z "
+         style="fill-rule:evenodd;stroke:#000000;stroke-width:1.0pt;"
+         transform="scale(0.4) rotate(180) translate(10,0)" />
+    </marker>
+  </defs>
+  <sodipodi:namedview
+     pagecolor="#ffffff"
+     bordercolor="#666666"
+     borderopacity="1"
+     objecttolerance="10"
+     gridtolerance="10"
+     guidetolerance="10"
+     inkscape:pageopacity="0"
+     inkscape:pageshadow="2"
+     inkscape:window-width="973"
+     inkscape:window-height="1137"
+     id="namedview102"
+     showgrid="false"
+     inkscape:zoom="0.9743589"
+     inkscape:cx="409.50003"
+     inkscape:cy="400.49997"
+     inkscape:window-x="915"
+     inkscape:window-y="24"
+     inkscape:window-maximized="0"
+     inkscape:current-layer="g4" />
+  <g
+     style="stroke-width:.025in; fill:none"
+     id="g4">
+    <!-- Line: box -->
+    <rect
+       x="0"
+       y="0"
+       width="10800"
+       height="5625"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffff00; "
+       id="rect6" />
+    <!-- Line: box -->
+    <rect
+       x="1125"
+       y="3600"
+       width="2700"
+       height="1350"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect8" />
+    <!-- Line: box -->
+    <rect
+       x="3825"
+       y="900"
+       width="2700"
+       height="1350"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect10" />
+    <!-- Line: box -->
+    <rect
+       x="6525"
+       y="3600"
+       width="2700"
+       height="1350"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect12" />
+    <!-- Line -->
+    <polyline
+       points="3375,6525 3375,5046 "
+       style="stroke:#00d1d1;stroke-width:44.9934641;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline14" />
+    <!-- Arrowhead on XXXpoint 3375 6525 - 3375 4860-->
+    <!-- Circle -->
+    <circle
+       cx="7425"
+       cy="6075"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle18" />
+    <!-- Circle -->
+    <circle
+       cx="7875"
+       cy="6075"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle20" />
+    <!-- Circle -->
+    <circle
+       cx="8325"
+       cy="6075"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle22" />
+    <!-- Circle -->
+    <circle
+       cx="2025"
+       cy="6075"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle24" />
+    <!-- Circle -->
+    <circle
+       cx="2475"
+       cy="6075"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle26" />
+    <!-- Circle -->
+    <circle
+       cx="2925"
+       cy="6075"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle28" />
+    <!-- Circle -->
+    <circle
+       cx="4725"
+       cy="4275"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle30" />
+    <!-- Circle -->
+    <circle
+       cx="5175"
+       cy="4275"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle32" />
+    <!-- Circle -->
+    <circle
+       cx="5625"
+       cy="4275"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle34" />
+    <!-- Line: box -->
+    <rect
+       x="2025"
+       y="6525"
+       width="2700"
+       height="1800"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect36" />
+    <!-- Line -->
+    <polyline
+       points="2475,3600 3975,2310 "
+       style="stroke:#00d1d1;stroke-width:44.9934641;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline38" />
+    <!-- Arrowhead on XXXpoint 2475 3600 - 4116 2190-->
+    <!-- Line -->
+    <polyline
+       points="7875,3600 6372,2310 "
+       style="stroke:#00d1d1;stroke-width:44.9934641;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline42" />
+    <!-- Arrowhead on XXXpoint 7875 3600 - 6231 2190-->
+    <!-- Line -->
+    <polyline
+       points="6975,8775 6975,5046 "
+       style="stroke:#00d1d1;stroke-width:44.9934641;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline46" />
+    <!-- Arrowhead on XXXpoint 6975 8775 - 6975 4860-->
+    <!-- Line -->
+    <polyline
+       points="1575,8775 1575,5046 "
+       style="stroke:#00d1d1;stroke-width:44.9934641;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline50" />
+    <!-- Arrowhead on XXXpoint 1575 8775 - 1575 4860-->
+    <!-- Line -->
+    <polyline
+       points="8775,6525 8775,5046 "
+       style="stroke:#00d1d1;stroke-width:44.9934641;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline54" />
+    <!-- Arrowhead on XXXpoint 8775 6525 - 8775 4860-->
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1575"
+       y="9225"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text58">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1575"
+       y="9675"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text60">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1575"
+       y="10350"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="324"
+       text-anchor="middle"
+       id="text62">CPU 0</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="3375"
+       y="6975"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text64">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="3375"
+       y="7425"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text66">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="3375"
+       y="8100"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="324"
+       text-anchor="middle"
+       id="text68">CPU 15</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="6975"
+       y="9225"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text70">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="6975"
+       y="9675"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text72">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="6975"
+       y="10350"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="324"
+       text-anchor="middle"
+       id="text74">CPU 1007</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="8730"
+       y="6930"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text76">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="8730"
+       y="7380"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text78">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="8730"
+       y="8055"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="324"
+       text-anchor="middle"
+       id="text80">CPU 1023</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="225"
+       y="450"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="start"
+       id="text82">struct rcu_state</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="2475"
+       y="4050"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text84">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="2475"
+       y="4500"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text86">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="7875"
+       y="4500"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text88">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="7875"
+       y="4050"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text90">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="5175"
+       y="1350"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text92">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="5175"
+       y="1800"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text94">rcu_node</text>
+    <!-- Line: box -->
+    <rect
+       x="225"
+       y="8775"
+       width="2700"
+       height="1800"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect96" />
+    <!-- Line: box -->
+    <rect
+       x="5625"
+       y="8775"
+       width="2700"
+       height="1800"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect98" />
+    <!-- Line: box -->
+    <rect
+       x="7380"
+       y="6480"
+       width="2700"
+       height="1800"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect100" />
+  </g>
+</svg>
diff --git a/Documentation/RCU/Design/Data-Structures/BigTreeClassicRCUBH.svg b/Documentation/RCU/Design/Data-Structures/BigTreeClassicRCUBH.svg
new file mode 100644
index 000000000000..9bbb1944f962
--- /dev/null
+++ b/Documentation/RCU/Design/Data-Structures/BigTreeClassicRCUBH.svg
@@ -0,0 +1,499 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!-- Creator: fig2dev Version 3.2 Patchlevel 5e -->
+
+<!-- CreationDate: Wed Dec  9 17:26:09 2015 -->
+
+<!-- Magnification: 2.000 -->
+
+<svg
+   xmlns:dc="http://purl.org/dc/elements/1.1/"
+   xmlns:cc="http://creativecommons.org/ns#"
+   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+   xmlns:svg="http://www.w3.org/2000/svg"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
+   width="5.7in"
+   height="6.6in"
+   viewBox="-44 -44 6838 7888"
+   id="svg2"
+   version="1.1"
+   inkscape:version="0.48.4 r9939"
+   sodipodi:docname="BigTreeClassicRCUBH.fig">
+  <metadata
+     id="metadata110">
+    <rdf:RDF>
+      <cc:Work
+         rdf:about="">
+        <dc:format>image/svg+xml</dc:format>
+        <dc:type
+           rdf:resource="http://purl.org/dc/dcmitype/StillImage" />
+        <dc:title></dc:title>
+      </cc:Work>
+    </rdf:RDF>
+  </metadata>
+  <defs
+     id="defs108">
+    <marker
+       inkscape:stockid="Arrow1Mend"
+       orient="auto"
+       refY="0.0"
+       refX="0.0"
+       id="Arrow1Mend"
+       style="overflow:visible;">
+      <path
+         id="path3868"
+         d="M 0.0,0.0 L 5.0,-5.0 L -12.5,0.0 L 5.0,5.0 L 0.0,0.0 z "
+         style="fill-rule:evenodd;stroke:#000000;stroke-width:1.0pt;"
+         transform="scale(0.4) rotate(180) translate(10,0)" />
+    </marker>
+    <marker
+       inkscape:stockid="Arrow2Mend"
+       orient="auto"
+       refY="0.0"
+       refX="0.0"
+       id="Arrow2Mend"
+       style="overflow:visible;">
+      <path
+         id="path3886"
+         style="fill-rule:evenodd;stroke-width:0.62500000;stroke-linejoin:round;"
+         d="M 8.7185878,4.0337352 L -2.2072895,0.016013256 L 8.7185884,-4.0017078 C 6.9730900,-1.6296469 6.9831476,1.6157441 8.7185878,4.0337352 z "
+         transform="scale(0.6) rotate(180) translate(0,0)" />
+    </marker>
+  </defs>
+  <sodipodi:namedview
+     pagecolor="#ffffff"
+     bordercolor="#666666"
+     borderopacity="1"
+     objecttolerance="10"
+     gridtolerance="10"
+     guidetolerance="10"
+     inkscape:pageopacity="0"
+     inkscape:pageshadow="2"
+     inkscape:window-width="878"
+     inkscape:window-height="1148"
+     id="namedview106"
+     showgrid="false"
+     inkscape:zoom="1.3547758"
+     inkscape:cx="256.5"
+     inkscape:cy="297"
+     inkscape:window-x="45"
+     inkscape:window-y="24"
+     inkscape:window-maximized="0"
+     inkscape:current-layer="g4" />
+  <g
+     style="stroke-width:.025in; fill:none"
+     id="g4">
+    <!-- Line: box -->
+    <rect
+       x="450"
+       y="0"
+       width="6300"
+       height="7350"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffffff; "
+       id="rect6" />
+    <!-- Line: box -->
+    <rect
+       x="4950"
+       y="4950"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect8" />
+    <!-- Line: box -->
+    <rect
+       x="750"
+       y="600"
+       width="5700"
+       height="3750"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffff00; "
+       id="rect10" />
+    <!-- Line: box -->
+    <rect
+       x="0"
+       y="450"
+       width="6300"
+       height="7350"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffffff; "
+       id="rect12" />
+    <!-- Line: box -->
+    <rect
+       x="300"
+       y="1050"
+       width="5700"
+       height="3750"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffff00; "
+       id="rect14" />
+    <!-- Circle -->
+    <circle
+       cx="2850"
+       cy="3900"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle16" />
+    <!-- Circle -->
+    <circle
+       cx="3150"
+       cy="3900"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle18" />
+    <!-- Circle -->
+    <circle
+       cx="3450"
+       cy="3900"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle20" />
+    <!-- Circle -->
+    <circle
+       cx="1350"
+       cy="5100"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle22" />
+    <!-- Circle -->
+    <circle
+       cx="1650"
+       cy="5100"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle24" />
+    <!-- Circle -->
+    <circle
+       cx="1950"
+       cy="5100"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle26" />
+    <!-- Circle -->
+    <circle
+       cx="4350"
+       cy="5100"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle28" />
+    <!-- Circle -->
+    <circle
+       cx="4650"
+       cy="5100"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle30" />
+    <!-- Circle -->
+    <circle
+       cx="4950"
+       cy="5100"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle32" />
+    <!-- Line -->
+    <polyline
+       points="1350,3450 2350,2590 "
+       style="stroke:#00d1d1;stroke-width:30.0045575;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline34" />
+    <!-- Arrowhead on XXXpoint 1350 3450 - 2444 2510-->
+    <!-- Line -->
+    <polyline
+       points="4950,3450 3948,2590 "
+       style="stroke:#00d1d1;stroke-width:30.0045575;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline38" />
+    <!-- Arrowhead on XXXpoint 4950 3450 - 3854 2510-->
+    <!-- Line: box -->
+    <rect
+       x="750"
+       y="3450"
+       width="1800"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect42" />
+    <!-- Line -->
+    <polyline
+       points="2250,5400 2250,4414 "
+       style="stroke:#00d1d1;stroke-width:30.0045575;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline44" />
+    <!-- Arrowhead on XXXpoint 2250 5400 - 2250 4290-->
+    <!-- Line: box -->
+    <rect
+       x="1500"
+       y="5400"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect48" />
+    <!-- Line: box -->
+    <rect
+       x="300"
+       y="6600"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect50" />
+    <!-- Line: box -->
+    <rect
+       x="3750"
+       y="3450"
+       width="1800"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect52" />
+    <!-- Line: box -->
+    <rect
+       x="4500"
+       y="5400"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect54" />
+    <!-- Line: box -->
+    <rect
+       x="3300"
+       y="6600"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect56" />
+    <!-- Line: box -->
+    <rect
+       x="2250"
+       y="1650"
+       width="1800"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect58" />
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="6450"
+       y="300"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="192"
+       text-anchor="end"
+       id="text60">rcu_bh</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="3150"
+       y="1950"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text62">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="3150"
+       y="2250"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text64">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1650"
+       y="3750"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text66">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1650"
+       y="4050"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text68">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="4650"
+       y="4050"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text70">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="4650"
+       y="3750"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text72">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="2250"
+       y="5700"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text74">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="2250"
+       y="6000"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text76">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1050"
+       y="6900"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text78">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1050"
+       y="7200"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text80">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="5250"
+       y="5700"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text82">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="5250"
+       y="6000"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text84">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="4050"
+       y="6900"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text86">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="4050"
+       y="7200"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text88">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="450"
+       y="1350"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="start"
+       id="text90">struct rcu_state</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="6000"
+       y="750"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="192"
+       text-anchor="end"
+       id="text92">rcu_sched</text>
+    <!-- Line -->
+    <polyline
+       points="5250,5400 5250,4414 "
+       style="stroke:#00d1d1;stroke-width:30.0045575;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline94" />
+    <!-- Arrowhead on XXXpoint 5250 5400 - 5250 4290-->
+    <!-- Line -->
+    <polyline
+       points="4050,6600 4050,4414 "
+       style="stroke:#00d1d1;stroke-width:30.0045575;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline98" />
+    <!-- Arrowhead on XXXpoint 4050 6600 - 4050 4290-->
+    <!-- Line -->
+    <polyline
+       points="1050,6600 1050,4414 "
+       style="stroke:#00d1d1;stroke-width:30.0045575;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline102" />
+    <!-- Arrowhead on XXXpoint 1050 6600 - 1050 4290-->
+  </g>
+</svg>
diff --git a/Documentation/RCU/Design/Data-Structures/BigTreeClassicRCUBHdyntick.svg b/Documentation/RCU/Design/Data-Structures/BigTreeClassicRCUBHdyntick.svg
new file mode 100644
index 000000000000..21ba7823479d
--- /dev/null
+++ b/Documentation/RCU/Design/Data-Structures/BigTreeClassicRCUBHdyntick.svg
@@ -0,0 +1,695 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!-- Creator: fig2dev Version 3.2 Patchlevel 5e -->
+
+<!-- CreationDate: Wed Dec  9 17:20:02 2015 -->
+
+<!-- Magnification: 2.000 -->
+
+<svg
+   xmlns:dc="http://purl.org/dc/elements/1.1/"
+   xmlns:cc="http://creativecommons.org/ns#"
+   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+   xmlns:svg="http://www.w3.org/2000/svg"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
+   width="5.7in"
+   height="8.6in"
+   viewBox="-44 -44 6838 10288"
+   id="svg2"
+   version="1.1"
+   inkscape:version="0.48.4 r9939"
+   sodipodi:docname="BigTreeClassicRCUBHdyntick.fig">
+  <metadata
+     id="metadata166">
+    <rdf:RDF>
+      <cc:Work
+         rdf:about="">
+        <dc:format>image/svg+xml</dc:format>
+        <dc:type
+           rdf:resource="http://purl.org/dc/dcmitype/StillImage" />
+        <dc:title></dc:title>
+      </cc:Work>
+    </rdf:RDF>
+  </metadata>
+  <defs
+     id="defs164">
+    <marker
+       inkscape:stockid="Arrow1Mend"
+       orient="auto"
+       refY="0.0"
+       refX="0.0"
+       id="Arrow1Mend"
+       style="overflow:visible;">
+      <path
+         id="path3924"
+         d="M 0.0,0.0 L 5.0,-5.0 L -12.5,0.0 L 5.0,5.0 L 0.0,0.0 z "
+         style="fill-rule:evenodd;stroke:#000000;stroke-width:1.0pt;"
+         transform="scale(0.4) rotate(180) translate(10,0)" />
+    </marker>
+    <marker
+       inkscape:stockid="Arrow2Lend"
+       orient="auto"
+       refY="0.0"
+       refX="0.0"
+       id="Arrow2Lend"
+       style="overflow:visible;">
+      <path
+         id="path3936"
+         style="fill-rule:evenodd;stroke-width:0.62500000;stroke-linejoin:round;"
+         d="M 8.7185878,4.0337352 L -2.2072895,0.016013256 L 8.7185884,-4.0017078 C 6.9730900,-1.6296469 6.9831476,1.6157441 8.7185878,4.0337352 z "
+         transform="scale(1.1) rotate(180) translate(1,0)" />
+    </marker>
+  </defs>
+  <sodipodi:namedview
+     pagecolor="#ffffff"
+     bordercolor="#666666"
+     borderopacity="1"
+     objecttolerance="10"
+     gridtolerance="10"
+     guidetolerance="10"
+     inkscape:pageopacity="0"
+     inkscape:pageshadow="2"
+     inkscape:window-width="845"
+     inkscape:window-height="988"
+     id="namedview162"
+     showgrid="false"
+     inkscape:zoom="1.0452196"
+     inkscape:cx="256.5"
+     inkscape:cy="387.00003"
+     inkscape:window-x="356"
+     inkscape:window-y="61"
+     inkscape:window-maximized="0"
+     inkscape:current-layer="g4" />
+  <g
+     style="stroke-width:.025in; fill:none"
+     id="g4">
+    <!-- Line: box -->
+    <rect
+       x="450"
+       y="0"
+       width="6300"
+       height="7350"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffffff; "
+       id="rect6" />
+    <!-- Line: box -->
+    <rect
+       x="4950"
+       y="4950"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect8" />
+    <!-- Line: box -->
+    <rect
+       x="750"
+       y="600"
+       width="5700"
+       height="3750"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffff00; "
+       id="rect10" />
+    <!-- Line -->
+    <polyline
+       points="5250,8100 5688,5912 "
+       style="stroke:#00ff00;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="polyline12" />
+    <!-- Arrowhead on XXXpoint 5250 8100 - 5710 5790-->
+    <polyline
+       points="5714 6068 5704 5822 5598 6044 "
+       style="stroke:#00ff00;stroke-width:14;stroke-miterlimit:8; "
+       id="polyline14" />
+    <!-- Line -->
+    <polyline
+       points="4050,9300 4486,7262 "
+       style="stroke:#00ff00;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="polyline16" />
+    <!-- Arrowhead on XXXpoint 4050 9300 - 4512 7140-->
+    <polyline
+       points="4514 7418 4506 7172 4396 7394 "
+       style="stroke:#00ff00;stroke-width:14;stroke-miterlimit:8; "
+       id="polyline18" />
+    <!-- Line -->
+    <polyline
+       points="1040,9300 1476,7262 "
+       style="stroke:#00ff00;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="polyline20" />
+    <!-- Arrowhead on XXXpoint 1040 9300 - 1502 7140-->
+    <polyline
+       points="1504 7418 1496 7172 1386 7394 "
+       style="stroke:#00ff00;stroke-width:14;stroke-miterlimit:8; "
+       id="polyline22" />
+    <!-- Line -->
+    <polyline
+       points="2240,8100 2676,6062 "
+       style="stroke:#00ff00;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="polyline24" />
+    <!-- Arrowhead on XXXpoint 2240 8100 - 2702 5940-->
+    <polyline
+       points="2704 6218 2696 5972 2586 6194 "
+       style="stroke:#00ff00;stroke-width:14;stroke-miterlimit:8; "
+       id="polyline26" />
+    <!-- Line: box -->
+    <rect
+       x="0"
+       y="450"
+       width="6300"
+       height="7350"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffffff; "
+       id="rect28" />
+    <!-- Line: box -->
+    <rect
+       x="300"
+       y="1050"
+       width="5700"
+       height="3750"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffff00; "
+       id="rect30" />
+    <!-- Line -->
+    <polyline
+       points="1350,3450 2350,2590 "
+       style="stroke:#00d1d1;stroke-width:30.0045575;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline32" />
+    <!-- Arrowhead on XXXpoint 1350 3450 - 2444 2510-->
+    <!-- Line -->
+    <polyline
+       points="4950,3450 3948,2590 "
+       style="stroke:#00d1d1;stroke-width:30.0045575;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline36" />
+    <!-- Arrowhead on XXXpoint 4950 3450 - 3854 2510-->
+    <!-- Line -->
+    <polyline
+       points="4050,6600 4050,4414 "
+       style="stroke:#00d1d1;stroke-width:30.00455750000000066;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline40" />
+    <!-- Arrowhead on XXXpoint 4050 6600 - 4050 4290-->
+    <!-- Line -->
+    <polyline
+       points="1050,6600 1050,4414 "
+       style="stroke:#00d1d1;stroke-width:30.00455750000000066;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline44" />
+    <!-- Arrowhead on XXXpoint 1050 6600 - 1050 4290-->
+    <!-- Line -->
+    <polyline
+       points="2250,5400 2250,4414 "
+       style="stroke:#00d1d1;stroke-width:30.00455750000000066;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline48" />
+    <!-- Arrowhead on XXXpoint 2250 5400 - 2250 4290-->
+    <!-- Line -->
+    <polyline
+       points="2250,8100 2250,6364 "
+       style="stroke:#00ff00;stroke-width:30;stroke-linejoin:miter;stroke-linecap:butt;marker-end:url(#Arrow1Mend)"
+       id="polyline52" />
+    <!-- Arrowhead on XXXpoint 2250 8100 - 2250 6240-->
+    <!-- Line -->
+    <polyline
+       points="1050,9300 1050,7564 "
+       style="stroke:#00ff00;stroke-width:30;stroke-linejoin:miter;stroke-linecap:butt;marker-end:url(#Arrow1Mend)"
+       id="polyline56" />
+    <!-- Arrowhead on XXXpoint 1050 9300 - 1050 7440-->
+    <!-- Line -->
+    <polyline
+       points="4050,9300 4050,7564 "
+       style="stroke:#00ff00;stroke-width:30;stroke-linejoin:miter;stroke-linecap:butt;marker-end:url(#Arrow1Mend)"
+       id="polyline60" />
+    <!-- Arrowhead on XXXpoint 4050 9300 - 4050 7440-->
+    <!-- Line -->
+    <polyline
+       points="5250,8100 5250,6364 "
+       style="stroke:#00ff00;stroke-width:30;stroke-linejoin:miter;stroke-linecap:butt;marker-end:url(#Arrow1Mend)"
+       id="polyline64" />
+    <!-- Arrowhead on XXXpoint 5250 8100 - 5250 6240-->
+    <!-- Circle -->
+    <circle
+       cx="2850"
+       cy="3900"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle68" />
+    <!-- Circle -->
+    <circle
+       cx="3150"
+       cy="3900"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle70" />
+    <!-- Circle -->
+    <circle
+       cx="3450"
+       cy="3900"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle72" />
+    <!-- Circle -->
+    <circle
+       cx="1350"
+       cy="5100"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle74" />
+    <!-- Circle -->
+    <circle
+       cx="1650"
+       cy="5100"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle76" />
+    <!-- Circle -->
+    <circle
+       cx="1950"
+       cy="5100"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle78" />
+    <!-- Circle -->
+    <circle
+       cx="4350"
+       cy="5100"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle80" />
+    <!-- Circle -->
+    <circle
+       cx="4650"
+       cy="5100"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle82" />
+    <!-- Circle -->
+    <circle
+       cx="4950"
+       cy="5100"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle84" />
+    <!-- Line: box -->
+    <rect
+       x="750"
+       y="3450"
+       width="1800"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect86" />
+    <!-- Line: box -->
+    <rect
+       x="300"
+       y="6600"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect88" />
+    <!-- Line: box -->
+    <rect
+       x="3750"
+       y="3450"
+       width="1800"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect90" />
+    <!-- Line: box -->
+    <rect
+       x="4500"
+       y="5400"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect92" />
+    <!-- Line: box -->
+    <rect
+       x="3300"
+       y="6600"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect94" />
+    <!-- Line: box -->
+    <rect
+       x="2250"
+       y="1650"
+       width="1800"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect96" />
+    <!-- Line: box -->
+    <rect
+       x="0"
+       y="9300"
+       width="2100"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#00ff00; "
+       id="rect98" />
+    <!-- Line: box -->
+    <rect
+       x="1350"
+       y="8100"
+       width="2100"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#00ff00; "
+       id="rect100" />
+    <!-- Line: box -->
+    <rect
+       x="3000"
+       y="9300"
+       width="2100"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#00ff00; "
+       id="rect102" />
+    <!-- Line: box -->
+    <rect
+       x="4350"
+       y="8100"
+       width="2100"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#00ff00; "
+       id="rect104" />
+    <!-- Line: box -->
+    <rect
+       x="1500"
+       y="5400"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect106" />
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="6450"
+       y="300"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="192"
+       text-anchor="end"
+       id="text108">rcu_bh</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="3150"
+       y="1950"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text110">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="3150"
+       y="2250"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text112">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1650"
+       y="3750"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text114">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1650"
+       y="4050"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text116">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="4650"
+       y="4050"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text118">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="4650"
+       y="3750"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text120">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="2250"
+       y="5700"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text122">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="2250"
+       y="6000"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text124">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1050"
+       y="6900"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text126">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1050"
+       y="7200"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text128">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="5250"
+       y="5700"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text130">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="5250"
+       y="6000"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text132">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="4050"
+       y="6900"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text134">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="4050"
+       y="7200"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text136">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="450"
+       y="1350"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="start"
+       id="text138">struct rcu_state</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1050"
+       y="9600"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text140">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1050"
+       y="9900"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text142">rcu_dynticks</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="4050"
+       y="9600"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text144">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="4050"
+       y="9900"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text146">rcu_dynticks</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="2400"
+       y="8400"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text148">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="2400"
+       y="8700"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text150">rcu_dynticks</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="5400"
+       y="8400"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text152">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="5400"
+       y="8700"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text154">rcu_dynticks</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="6000"
+       y="750"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="192"
+       text-anchor="end"
+       id="text156">rcu_sched</text>
+    <!-- Line -->
+    <polyline
+       points="5250,5400 5250,4414 "
+       style="stroke:#00d1d1;stroke-width:30.00455750000000066;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline158" />
+    <!-- Arrowhead on XXXpoint 5250 5400 - 5250 4290-->
+  </g>
+</svg>
diff --git a/Documentation/RCU/Design/Data-Structures/BigTreePreemptRCUBHdyntick.svg b/Documentation/RCU/Design/Data-Structures/BigTreePreemptRCUBHdyntick.svg
new file mode 100644
index 000000000000..15adcac036c7
--- /dev/null
+++ b/Documentation/RCU/Design/Data-Structures/BigTreePreemptRCUBHdyntick.svg
@@ -0,0 +1,741 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!-- Creator: fig2dev Version 3.2 Patchlevel 5e -->
+
+<!-- CreationDate: Wed Dec  9 17:32:59 2015 -->
+
+<!-- Magnification: 2.000 -->
+
+<svg
+   xmlns:dc="http://purl.org/dc/elements/1.1/"
+   xmlns:cc="http://creativecommons.org/ns#"
+   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+   xmlns:svg="http://www.w3.org/2000/svg"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
+   width="6.1in"
+   height="8.9in"
+   viewBox="-44 -44 7288 10738"
+   id="svg2"
+   version="1.1"
+   inkscape:version="0.48.4 r9939"
+   sodipodi:docname="BigTreePreemptRCUBHdyntick.fig">
+  <metadata
+     id="metadata182">
+    <rdf:RDF>
+      <cc:Work
+         rdf:about="">
+        <dc:format>image/svg+xml</dc:format>
+        <dc:type
+           rdf:resource="http://purl.org/dc/dcmitype/StillImage" />
+        <dc:title></dc:title>
+      </cc:Work>
+    </rdf:RDF>
+  </metadata>
+  <defs
+     id="defs180">
+    <marker
+       inkscape:stockid="Arrow1Mend"
+       orient="auto"
+       refY="0.0"
+       refX="0.0"
+       id="Arrow1Mend"
+       style="overflow:visible;">
+      <path
+         id="path3940"
+         d="M 0.0,0.0 L 5.0,-5.0 L -12.5,0.0 L 5.0,5.0 L 0.0,0.0 z "
+         style="fill-rule:evenodd;stroke:#000000;stroke-width:1.0pt;"
+         transform="scale(0.4) rotate(180) translate(10,0)" />
+    </marker>
+  </defs>
+  <sodipodi:namedview
+     pagecolor="#ffffff"
+     bordercolor="#666666"
+     borderopacity="1"
+     objecttolerance="10"
+     gridtolerance="10"
+     guidetolerance="10"
+     inkscape:pageopacity="0"
+     inkscape:pageshadow="2"
+     inkscape:window-width="874"
+     inkscape:window-height="1148"
+     id="namedview178"
+     showgrid="false"
+     inkscape:zoom="1.2097379"
+     inkscape:cx="274.5"
+     inkscape:cy="400.49997"
+     inkscape:window-x="946"
+     inkscape:window-y="24"
+     inkscape:window-maximized="0"
+     inkscape:current-layer="g4" />
+  <g
+     style="stroke-width:.025in; fill:none"
+     id="g4">
+    <!-- Line: box -->
+    <rect
+       x="900"
+       y="0"
+       width="6300"
+       height="7350"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffffff; "
+       id="rect6" />
+    <!-- Line: box -->
+    <rect
+       x="1200"
+       y="600"
+       width="5700"
+       height="3750"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffff00; "
+       id="rect8" />
+    <!-- Line: box -->
+    <rect
+       x="5400"
+       y="4950"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect10" />
+    <!-- Line: box -->
+    <rect
+       x="450"
+       y="450"
+       width="6300"
+       height="7350"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffffff; "
+       id="rect12" />
+    <!-- Line: box -->
+    <rect
+       x="750"
+       y="1050"
+       width="5700"
+       height="3750"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffff00; "
+       id="rect14" />
+    <!-- Line: box -->
+    <rect
+       x="4950"
+       y="5400"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect16" />
+    <!-- Line -->
+    <polyline
+       points="5250,8550 5688,6362 "
+       style="stroke:#00ff00;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="polyline18" />
+    <!-- Arrowhead on XXXpoint 5250 8550 - 5710 6240-->
+    <polyline
+       points="5714 6518 5704 6272 5598 6494 "
+       style="stroke:#00ff00;stroke-width:14;stroke-miterlimit:8; "
+       id="polyline20" />
+    <!-- Line -->
+    <polyline
+       points="4050,9750 4486,7712 "
+       style="stroke:#00ff00;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="polyline22" />
+    <!-- Arrowhead on XXXpoint 4050 9750 - 4512 7590-->
+    <polyline
+       points="4514 7868 4506 7622 4396 7844 "
+       style="stroke:#00ff00;stroke-width:14;stroke-miterlimit:8; "
+       id="polyline24" />
+    <!-- Line -->
+    <polyline
+       points="1040,9750 1476,7712 "
+       style="stroke:#00ff00;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="polyline26" />
+    <!-- Arrowhead on XXXpoint 1040 9750 - 1502 7590-->
+    <polyline
+       points="1504 7868 1496 7622 1386 7844 "
+       style="stroke:#00ff00;stroke-width:14;stroke-miterlimit:8; "
+       id="polyline28" />
+    <!-- Line -->
+    <polyline
+       points="2240,8550 2676,6512 "
+       style="stroke:#00ff00;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="polyline30" />
+    <!-- Arrowhead on XXXpoint 2240 8550 - 2702 6390-->
+    <polyline
+       points="2704 6668 2696 6422 2586 6644 "
+       style="stroke:#00ff00;stroke-width:14;stroke-miterlimit:8; "
+       id="polyline32" />
+    <!-- Line -->
+    <polyline
+       points="4050,9750 5682,6360 "
+       style="stroke:#00ff00;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="polyline34" />
+    <!-- Arrowhead on XXXpoint 4050 9750 - 5736 6246-->
+    <polyline
+       points="5672 6518 5722 6276 5562 6466 "
+       style="stroke:#00ff00;stroke-width:14;stroke-miterlimit:8; "
+       id="polyline36" />
+    <!-- Line -->
+    <polyline
+       points="1010,9750 2642,6360 "
+       style="stroke:#00ff00;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="polyline38" />
+    <!-- Arrowhead on XXXpoint 1010 9750 - 2696 6246-->
+    <polyline
+       points="2632 6518 2682 6276 2522 6466 "
+       style="stroke:#00ff00;stroke-width:14;stroke-miterlimit:8; "
+       id="polyline40" />
+    <!-- Line: box -->
+    <rect
+       x="0"
+       y="900"
+       width="6300"
+       height="7350"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffffff; "
+       id="rect42" />
+    <!-- Line: box -->
+    <rect
+       x="300"
+       y="1500"
+       width="5700"
+       height="3750"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffff00; "
+       id="rect44" />
+    <!-- Line -->
+    <polyline
+       points="1350,3900 2350,3040 "
+       style="stroke:#00d1d1;stroke-width:30.00205472;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline46" />
+    <!-- Arrowhead on XXXpoint 1350 3900 - 2444 2960-->
+    <!-- Line -->
+    <polyline
+       points="4950,3900 3948,3040 "
+       style="stroke:#00d1d1;stroke-width:30.00205472;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline50" />
+    <!-- Arrowhead on XXXpoint 4950 3900 - 3854 2960-->
+    <!-- Line -->
+    <polyline
+       points="4050,7050 4050,4864 "
+       style="stroke:#00d1d1;stroke-width:30.00205472;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline54" />
+    <!-- Arrowhead on XXXpoint 4050 7050 - 4050 4740-->
+    <!-- Line -->
+    <polyline
+       points="1050,7050 1050,4864 "
+       style="stroke:#00d1d1;stroke-width:30.00205472;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline58" />
+    <!-- Arrowhead on XXXpoint 1050 7050 - 1050 4740-->
+    <!-- Line -->
+    <polyline
+       points="2250,5850 2250,4864 "
+       style="stroke:#00d1d1;stroke-width:30.00205472;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline62" />
+    <!-- Arrowhead on XXXpoint 2250 5850 - 2250 4740-->
+    <!-- Line -->
+    <polyline
+       points="2250,8550 2250,6814 "
+       style="stroke:#00ff00;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="polyline66" />
+    <!-- Arrowhead on XXXpoint 2250 8550 - 2250 6690-->
+    <!-- Line -->
+    <polyline
+       points="1050,9750 1050,8014 "
+       style="stroke:#00ff00;stroke-width:30.00205472;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline70" />
+    <!-- Arrowhead on XXXpoint 1050 9750 - 1050 7890-->
+    <!-- Line -->
+    <polyline
+       points="4050,9750 4050,8014 "
+       style="stroke:#00ff00;stroke-width:30.00205472;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline74" />
+    <!-- Arrowhead on XXXpoint 4050 9750 - 4050 7890-->
+    <!-- Line -->
+    <polyline
+       points="5250,8550 5250,6814 "
+       style="stroke:#00ff00;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="polyline78" />
+    <!-- Arrowhead on XXXpoint 5250 8550 - 5250 6690-->
+    <!-- Circle -->
+    <circle
+       cx="2850"
+       cy="4350"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle82" />
+    <!-- Circle -->
+    <circle
+       cx="3150"
+       cy="4350"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle84" />
+    <!-- Circle -->
+    <circle
+       cx="3450"
+       cy="4350"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle86" />
+    <!-- Circle -->
+    <circle
+       cx="1350"
+       cy="5550"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle88" />
+    <!-- Circle -->
+    <circle
+       cx="1650"
+       cy="5550"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle90" />
+    <!-- Circle -->
+    <circle
+       cx="1950"
+       cy="5550"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle92" />
+    <!-- Circle -->
+    <circle
+       cx="4350"
+       cy="5550"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle94" />
+    <!-- Circle -->
+    <circle
+       cx="4650"
+       cy="5550"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle96" />
+    <!-- Circle -->
+    <circle
+       cx="4950"
+       cy="5550"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle98" />
+    <!-- Line: box -->
+    <rect
+       x="750"
+       y="3900"
+       width="1800"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect100" />
+    <!-- Line: box -->
+    <rect
+       x="300"
+       y="7050"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect102" />
+    <!-- Line: box -->
+    <rect
+       x="3750"
+       y="3900"
+       width="1800"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect104" />
+    <!-- Line: box -->
+    <rect
+       x="4500"
+       y="5850"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect106" />
+    <!-- Line: box -->
+    <rect
+       x="3300"
+       y="7050"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect108" />
+    <!-- Line: box -->
+    <rect
+       x="2250"
+       y="2100"
+       width="1800"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect110" />
+    <!-- Line: box -->
+    <rect
+       x="0"
+       y="9750"
+       width="2100"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#00ff00; "
+       id="rect112" />
+    <!-- Line: box -->
+    <rect
+       x="1350"
+       y="8550"
+       width="2100"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#00ff00; "
+       id="rect114" />
+    <!-- Line: box -->
+    <rect
+       x="3000"
+       y="9750"
+       width="2100"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#00ff00; "
+       id="rect116" />
+    <!-- Line: box -->
+    <rect
+       x="4350"
+       y="8550"
+       width="2100"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#00ff00; "
+       id="rect118" />
+    <!-- Line: box -->
+    <rect
+       x="1500"
+       y="5850"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect120" />
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="6450"
+       y="750"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="192"
+       text-anchor="end"
+       id="text122">rcu_bh</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="3150"
+       y="2400"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text124">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="3150"
+       y="2700"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text126">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1650"
+       y="4200"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text128">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1650"
+       y="4500"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text130">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="4650"
+       y="4500"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text132">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="4650"
+       y="4200"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text134">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="2250"
+       y="6150"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text136">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="2250"
+       y="6450"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text138">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1050"
+       y="7350"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text140">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1050"
+       y="7650"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text142">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="5250"
+       y="6150"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text144">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="5250"
+       y="6450"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text146">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="4050"
+       y="7350"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text148">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="4050"
+       y="7650"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text150">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="450"
+       y="1800"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="start"
+       id="text152">struct rcu_state</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1050"
+       y="10050"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text154">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1050"
+       y="10350"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text156">rcu_dynticks</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="4050"
+       y="10050"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text158">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="4050"
+       y="10350"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text160">rcu_dynticks</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="2400"
+       y="8850"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text162">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="2400"
+       y="9150"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text164">rcu_dynticks</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="5400"
+       y="8850"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text166">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="5400"
+       y="9150"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text168">rcu_dynticks</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="6900"
+       y="300"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="192"
+       text-anchor="end"
+       id="text170">rcu_preempt</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="6000"
+       y="1200"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="192"
+       text-anchor="end"
+       id="text172">rcu_sched</text>
+    <!-- Line -->
+    <polyline
+       points="5250,5850 5250,4864 "
+       style="stroke:#00d1d1;stroke-width:30.00205472;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline174" />
+    <!-- Arrowhead on XXXpoint 5250 5850 - 5250 4740-->
+  </g>
+</svg>
diff --git a/Documentation/RCU/Design/Data-Structures/BigTreePreemptRCUBHdyntickCB.svg b/Documentation/RCU/Design/Data-Structures/BigTreePreemptRCUBHdyntickCB.svg
new file mode 100644
index 000000000000..bbc3801470d0
--- /dev/null
+++ b/Documentation/RCU/Design/Data-Structures/BigTreePreemptRCUBHdyntickCB.svg
@@ -0,0 +1,858 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!-- Creator: fig2dev Version 3.2 Patchlevel 5e -->
+
+<!-- CreationDate: Wed Dec  9 17:29:48 2015 -->
+
+<!-- Magnification: 2.000 -->
+
+<svg
+   xmlns:dc="http://purl.org/dc/elements/1.1/"
+   xmlns:cc="http://creativecommons.org/ns#"
+   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+   xmlns:svg="http://www.w3.org/2000/svg"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
+   width="7.4in"
+   height="9.9in"
+   viewBox="-44 -44 8938 11938"
+   id="svg2"
+   version="1.1"
+   inkscape:version="0.48.4 r9939"
+   sodipodi:docname="BigTreePreemptRCUBHdyntickCB.svg">
+  <metadata
+     id="metadata212">
+    <rdf:RDF>
+      <cc:Work
+         rdf:about="">
+        <dc:format>image/svg+xml</dc:format>
+        <dc:type
+           rdf:resource="http://purl.org/dc/dcmitype/StillImage" />
+        <dc:title></dc:title>
+      </cc:Work>
+    </rdf:RDF>
+  </metadata>
+  <defs
+     id="defs210">
+    <marker
+       inkscape:stockid="Arrow1Mend"
+       orient="auto"
+       refY="0.0"
+       refX="0.0"
+       id="Arrow1Mend"
+       style="overflow:visible;">
+      <path
+         id="path3970"
+         d="M 0.0,0.0 L 5.0,-5.0 L -12.5,0.0 L 5.0,5.0 L 0.0,0.0 z "
+         style="fill-rule:evenodd;stroke:#000000;stroke-width:1.0pt;"
+         transform="scale(0.4) rotate(180) translate(10,0)" />
+    </marker>
+  </defs>
+  <sodipodi:namedview
+     pagecolor="#ffffff"
+     bordercolor="#666666"
+     borderopacity="1"
+     objecttolerance="10"
+     gridtolerance="10"
+     guidetolerance="10"
+     inkscape:pageopacity="0"
+     inkscape:pageshadow="2"
+     inkscape:window-width="881"
+     inkscape:window-height="1128"
+     id="namedview208"
+     showgrid="false"
+     inkscape:zoom="1.0195195"
+     inkscape:cx="333"
+     inkscape:cy="445.49997"
+     inkscape:window-x="936"
+     inkscape:window-y="24"
+     inkscape:window-maximized="0"
+     inkscape:current-layer="g4" />
+  <g
+     style="stroke-width:.025in; fill:none"
+     id="g4">
+    <!-- Line: box -->
+    <rect
+       x="900"
+       y="0"
+       width="6300"
+       height="7350"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffffff; "
+       id="rect6" />
+    <!-- Line: box -->
+    <rect
+       x="1200"
+       y="600"
+       width="5700"
+       height="3750"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffff00; "
+       id="rect8" />
+    <!-- Line: box -->
+    <rect
+       x="5400"
+       y="4950"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect10" />
+    <!-- Line: box -->
+    <rect
+       x="450"
+       y="450"
+       width="6300"
+       height="7350"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffffff; "
+       id="rect12" />
+    <!-- Line: box -->
+    <rect
+       x="750"
+       y="1050"
+       width="5700"
+       height="3750"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffff00; "
+       id="rect14" />
+    <!-- Line: box -->
+    <rect
+       x="4950"
+       y="5400"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect16" />
+    <!-- Line -->
+    <polyline
+       points="5250,8550 5688,6362 "
+       style="stroke:#00ff00;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="polyline18" />
+    <!-- Arrowhead on XXXpoint 5250 8550 - 5710 6240-->
+    <polyline
+       points="5714 6518 5704 6272 5598 6494 "
+       style="stroke:#00ff00;stroke-width:14;stroke-miterlimit:8; "
+       id="polyline20" />
+    <!-- Line -->
+    <polyline
+       points="4050,9750 4486,7712 "
+       style="stroke:#00ff00;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="polyline22" />
+    <!-- Arrowhead on XXXpoint 4050 9750 - 4512 7590-->
+    <polyline
+       points="4514 7868 4506 7622 4396 7844 "
+       style="stroke:#00ff00;stroke-width:14;stroke-miterlimit:8; "
+       id="polyline24" />
+    <!-- Line -->
+    <polyline
+       points="1040,9750 1476,7712 "
+       style="stroke:#00ff00;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="polyline26" />
+    <!-- Arrowhead on XXXpoint 1040 9750 - 1502 7590-->
+    <polyline
+       points="1504 7868 1496 7622 1386 7844 "
+       style="stroke:#00ff00;stroke-width:14;stroke-miterlimit:8; "
+       id="polyline28" />
+    <!-- Line -->
+    <polyline
+       points="2240,8550 2676,6512 "
+       style="stroke:#00ff00;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="polyline30" />
+    <!-- Arrowhead on XXXpoint 2240 8550 - 2702 6390-->
+    <polyline
+       points="2704 6668 2696 6422 2586 6644 "
+       style="stroke:#00ff00;stroke-width:14;stroke-miterlimit:8; "
+       id="polyline32" />
+    <!-- Line -->
+    <polyline
+       points="4050,9600 5692,6062 "
+       style="stroke:#00ff00;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="polyline34" />
+    <!-- Arrowhead on XXXpoint 4050 9600 - 5744 5948-->
+    <polyline
+       points="5682 6220 5730 5978 5574 6170 "
+       style="stroke:#00ff00;stroke-width:14;stroke-miterlimit:8; "
+       id="polyline36" />
+    <!-- Line -->
+    <polyline
+       points="1086,9600 2728,6062 "
+       style="stroke:#00ff00;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="polyline38" />
+    <!-- Arrowhead on XXXpoint 1086 9600 - 2780 5948-->
+    <polyline
+       points="2718 6220 2766 5978 2610 6170 "
+       style="stroke:#00ff00;stroke-width:14;stroke-miterlimit:8; "
+       id="polyline40" />
+    <!-- Line: box -->
+    <rect
+       x="0"
+       y="900"
+       width="6300"
+       height="7350"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffffff; "
+       id="rect42" />
+    <!-- Line: box -->
+    <rect
+       x="300"
+       y="1500"
+       width="5700"
+       height="3750"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffff00; "
+       id="rect44" />
+    <!-- Line -->
+    <polyline
+       points="1350,3900 2350,3040 "
+       style="stroke:#00d1d1;stroke-width:29.99463964;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline46" />
+    <!-- Arrowhead on XXXpoint 1350 3900 - 2444 2960-->
+    <!-- Line -->
+    <polyline
+       points="4950,3900 3948,3040 "
+       style="stroke:#00d1d1;stroke-width:29.99463964;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline50" />
+    <!-- Arrowhead on XXXpoint 4950 3900 - 3854 2960-->
+    <!-- Line -->
+    <polyline
+       points="4050,7050 4050,4864 "
+       style="stroke:#00d1d1;stroke-width:29.99463964;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline54" />
+    <!-- Arrowhead on XXXpoint 4050 7050 - 4050 4740-->
+    <!-- Line -->
+    <polyline
+       points="1050,7050 1050,4864 "
+       style="stroke:#00d1d1;stroke-width:29.99463964;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline58" />
+    <!-- Arrowhead on XXXpoint 1050 7050 - 1050 4740-->
+    <!-- Line -->
+    <polyline
+       points="2250,5850 2250,4864 "
+       style="stroke:#00d1d1;stroke-width:29.99463964;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline62" />
+    <!-- Arrowhead on XXXpoint 2250 5850 - 2250 4740-->
+    <!-- Line -->
+    <polyline
+       points="2250,8550 2250,6814 "
+       style="stroke:#00ff00;stroke-width:29.99463964;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline66" />
+    <!-- Arrowhead on XXXpoint 2250 8550 - 2250 6690-->
+    <!-- Line -->
+    <polyline
+       points="1050,9750 1050,8014 "
+       style="stroke:#00ff00;stroke-width:29.99463964;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline70" />
+    <!-- Arrowhead on XXXpoint 1050 9750 - 1050 7890-->
+    <!-- Line -->
+    <polyline
+       points="4050,9750 4050,8014 "
+       style="stroke:#00ff00;stroke-width:29.99463964;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline74" />
+    <!-- Arrowhead on XXXpoint 4050 9750 - 4050 7890-->
+    <!-- Line -->
+    <polyline
+       points="5250,8550 5250,6814 "
+       style="stroke:#00ff00;stroke-width:29.99463964;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline78" />
+    <!-- Arrowhead on XXXpoint 5250 8550 - 5250 6690-->
+    <!-- Line -->
+    <polyline
+       points="6000,6300 8048,7910 "
+       style="stroke:#87cfff;stroke-width:30;stroke-linejoin:miter;stroke-linecap:butt;marker-end:url(#Arrow1Mend)"
+       id="polyline82" />
+    <!-- Arrowhead on XXXpoint 6000 6300 - 8146 7986-->
+    <!-- Circle -->
+    <circle
+       cx="2850"
+       cy="4350"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle86" />
+    <!-- Circle -->
+    <circle
+       cx="3150"
+       cy="4350"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle88" />
+    <!-- Circle -->
+    <circle
+       cx="3450"
+       cy="4350"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle90" />
+    <!-- Circle -->
+    <circle
+       cx="1350"
+       cy="5550"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle92" />
+    <!-- Circle -->
+    <circle
+       cx="1650"
+       cy="5550"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle94" />
+    <!-- Circle -->
+    <circle
+       cx="1950"
+       cy="5550"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle96" />
+    <!-- Circle -->
+    <circle
+       cx="4350"
+       cy="5550"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle98" />
+    <!-- Circle -->
+    <circle
+       cx="4650"
+       cy="5550"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle100" />
+    <!-- Circle -->
+    <circle
+       cx="4950"
+       cy="5550"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle102" />
+    <!-- Line: box -->
+    <rect
+       x="7350"
+       y="7950"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect104" />
+    <!-- Line: box -->
+    <rect
+       x="7350"
+       y="9450"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect106" />
+    <!-- Line -->
+    <polyline
+       points="8100,8850 8100,9384 "
+       style="stroke:#000000;stroke-width:30;stroke-linejoin:miter;stroke-linecap:butt;marker-end:url(#Arrow1Mend)"
+       id="polyline108" />
+    <!-- Arrowhead on XXXpoint 8100 8850 - 8100 9510-->
+    <!-- Line: box -->
+    <rect
+       x="7350"
+       y="10950"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect112" />
+    <!-- Line -->
+    <polyline
+       points="8100,10350 8100,10884 "
+       style="stroke:#000000;stroke-width:30;stroke-linejoin:miter;stroke-linecap:butt;marker-end:url(#Arrow1Mend)"
+       id="polyline114" />
+    <!-- Arrowhead on XXXpoint 8100 10350 - 8100 11010-->
+    <!-- Line: box -->
+    <rect
+       x="750"
+       y="3900"
+       width="1800"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect118" />
+    <!-- Line: box -->
+    <rect
+       x="300"
+       y="7050"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect120" />
+    <!-- Line: box -->
+    <rect
+       x="3750"
+       y="3900"
+       width="1800"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect122" />
+    <!-- Line: box -->
+    <rect
+       x="4500"
+       y="5850"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect124" />
+    <!-- Line: box -->
+    <rect
+       x="3300"
+       y="7050"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect126" />
+    <!-- Line: box -->
+    <rect
+       x="2250"
+       y="2100"
+       width="1800"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect128" />
+    <!-- Line: box -->
+    <rect
+       x="0"
+       y="9750"
+       width="2100"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#00ff00; "
+       id="rect130" />
+    <!-- Line: box -->
+    <rect
+       x="1350"
+       y="8550"
+       width="2100"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#00ff00; "
+       id="rect132" />
+    <!-- Line: box -->
+    <rect
+       x="3000"
+       y="9750"
+       width="2100"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#00ff00; "
+       id="rect134" />
+    <!-- Line: box -->
+    <rect
+       x="4350"
+       y="8550"
+       width="2100"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#00ff00; "
+       id="rect136" />
+    <!-- Line: box -->
+    <rect
+       x="1500"
+       y="5850"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect138" />
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="8100"
+       y="8250"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text140">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="8100"
+       y="8550"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text142">rcu_head</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="8100"
+       y="9750"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text144">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="8100"
+       y="10050"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text146">rcu_head</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="8100"
+       y="11250"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text148">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="8100"
+       y="11550"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text150">rcu_head</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="6000"
+       y="1200"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="192"
+       text-anchor="end"
+       id="text152">rcu_sched</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="6450"
+       y="750"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="192"
+       text-anchor="end"
+       id="text154">rcu_bh</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="3150"
+       y="2400"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text156">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="3150"
+       y="2700"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text158">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1650"
+       y="4200"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text160">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1650"
+       y="4500"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text162">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="4650"
+       y="4500"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text164">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="4650"
+       y="4200"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text166">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="2250"
+       y="6150"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text168">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="2250"
+       y="6450"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text170">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1050"
+       y="7350"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text172">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1050"
+       y="7650"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text174">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="5250"
+       y="6150"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text176">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="5250"
+       y="6450"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text178">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="4050"
+       y="7350"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text180">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="4050"
+       y="7650"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text182">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="450"
+       y="1800"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="start"
+       id="text184">struct rcu_state</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1050"
+       y="10050"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text186">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1050"
+       y="10350"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text188">rcu_dynticks</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="4050"
+       y="10050"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text190">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="4050"
+       y="10350"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text192">rcu_dynticks</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="2400"
+       y="8850"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text194">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="2400"
+       y="9150"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text196">rcu_dynticks</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="5400"
+       y="8850"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text198">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="5400"
+       y="9150"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text200">rcu_dynticks</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="6900"
+       y="300"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="192"
+       text-anchor="end"
+       id="text202">rcu_preempt</text>
+    <!-- Line -->
+    <polyline
+       points="5250,5850 5250,4864 "
+       style="stroke:#00d1d1;stroke-width:29.99463964;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline204" />
+    <!-- Arrowhead on XXXpoint 5250 5850 - 5250 4740-->
+  </g>
+</svg>
diff --git a/Documentation/RCU/Design/Data-Structures/Data-Structures.html b/Documentation/RCU/Design/Data-Structures/Data-Structures.html
new file mode 100644
index 000000000000..7eb47ac25ad7
--- /dev/null
+++ b/Documentation/RCU/Design/Data-Structures/Data-Structures.html
@@ -0,0 +1,1333 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
+        "http://www.w3.org/TR/html4/loose.dtd">
+        <html>
+        <head><title>A Tour Through TREE_RCU's Data Structures [LWN.net]</title>
+        <meta HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
+
+           <p>January 27, 2016</p>
+           <p>This article was contributed by Paul E.&nbsp;McKenney</p>
+
+<h3>Introduction</h3>
+
+This document describes RCU's major data structures and their relationship
+to each other.
+
+<ol>
+<li>	<a href="#Data-Structure Relationships">
+	Data-Structure Relationships</a>
+<li>	<a href="#The rcu_state Structure">
+	The <tt>rcu_state</tt> Structure</a>
+<li>	<a href="#The rcu_node Structure">
+	The <tt>rcu_node</tt> Structure</a>
+<li>	<a href="#The rcu_data Structure">
+	The <tt>rcu_data</tt> Structure</a>
+<li>	<a href="#The rcu_dynticks Structure">
+	The <tt>rcu_dynticks</tt> Structure</a>
+<li>	<a href="#The rcu_head Structure">
+	The <tt>rcu_head</tt> Structure</a>
+<li>	<a href="#RCU-Specific Fields in the task_struct Structure">
+	RCU-Specific Fields in the <tt>task_struct</tt> Structure</a>
+<li>	<a href="#Accessor Functions">
+	Accessor Functions</a>
+</ol>
+
+At the end we have the
+<a href="#Answers to Quick Quizzes">answers to the quick quizzes</a>.
+
+<h3><a name="Data-Structure Relationships">Data-Structure Relationships</a></h3>
+
+<p>RCU is for all intents and purposes a large state machine, and its
+data structures maintain the state in such a way as to allow RCU readers
+to execute extremely quickly, while also processing the RCU grace periods
+requested by updaters in an efficient and extremely scalable fashion.
+The efficiency and scalability of RCU updaters is provided primarily
+by a combining tree, as shown below:
+
+</p><p><img src="BigTreeClassicRCU.svg" alt="BigTreeClassicRCU.svg" width="30%">
+
+</p><p>This diagram shows an enclosing <tt>rcu_state</tt> structure
+containing a tree of <tt>rcu_node</tt> structures.
+Each leaf node of the <tt>rcu_node</tt> tree has up to 16
+<tt>rcu_data</tt> structures associated with it, so that there
+are <tt>NR_CPUS</tt> number of <tt>rcu_data</tt> structures,
+one for each possible CPU.
+This structure is adjusted at boot time, if needed, to handle the
+common case where <tt>nr_cpu_ids</tt> is much less than
+<tt>NR_CPUs</tt>.
+For example, a number of Linux distributions set <tt>NR_CPUs=4096</tt>,
+which results in a three-level <tt>rcu_node</tt> tree.
+If the actual hardware has only 16 CPUs, RCU will adjust itself
+at boot time, resulting in an <tt>rcu_node</tt> tree with only a single node.
+
+</p><p>The purpose of this combining tree is to allow per-CPU events
+such as quiescent states, dyntick-idle transitions,
+and CPU hotplug operations to be processed efficiently
+and scalably.
+Quiescent states are recorded by the per-CPU <tt>rcu_data</tt> structures,
+and other events are recorded by the leaf-level <tt>rcu_node</tt>
+structures.
+All of these events are combined at each level of the tree until finally
+grace periods are completed at the tree's root <tt>rcu_node</tt>
+structure.
+A grace period can be completed at the root once every CPU
+(or, in the case of <tt>CONFIG_PREEMPT_RCU</tt>, task)
+has passed through a quiescent state.
+Once a grace period has completed, record of that fact is propagated
+back down the tree.
+
+</p><p>As can be seen from the diagram, on a 64-bit system
+a two-level tree with 64 leaves can accommodate 1,024 CPUs, with a fanout
+of 64 at the root and a fanout of 16 at the leaves.
+
+<table>
+<tr><th>&nbsp;</th></tr>
+<tr><th align="left">Quick Quiz:</th></tr>
+<tr><td>
+	Why isn't the fanout at the leaves also 64?
+</td></tr>
+<tr><th align="left">Answer:</th></tr>
+<tr><td bgcolor="#ffffff"><font color="ffffff">
+	Because there are more types of events that affect the leaf-level
+	<tt>rcu_node</tt> structures than further up the tree.
+	Therefore, if the leaf <tt>rcu_node</tt> structures have fanout of
+	64, the contention on these structures' <tt>-&gt;structures</tt>
+	becomes excessive.
+	Experimentation on a wide variety of systems has shown that a fanout
+	of 16 works well for the leaves of the <tt>rcu_node</tt> tree.
+	</font>
+
+	<p><font color="ffffff">Of course, further experience with
+	systems having hundreds or thousands of CPUs may demonstrate
+	that the fanout for the non-leaf <tt>rcu_node</tt> structures
+	must also be reduced.
+	Such reduction can be easily carried out when and if it proves
+	necessary.
+	In the meantime, if you are using such a system and running into
+	contention problems on the non-leaf <tt>rcu_node</tt> structures,
+	you may use the <tt>CONFIG_RCU_FANOUT</tt> kernel configuration
+	parameter to reduce the non-leaf fanout as needed.
+	</font>
+
+	<p><font color="ffffff">Kernels built for systems with
+	strong NUMA characteristics might also need to adjust
+	<tt>CONFIG_RCU_FANOUT</tt> so that the domains of the
+	<tt>rcu_node</tt> structures align with hardware boundaries.
+	However, there has thus far been no need for this.
+</font></td></tr>
+<tr><td>&nbsp;</td></tr>
+</table>
+
+<p>If your system has more than 1,024 CPUs (or more than 512 CPUs on
+a 32-bit system), then RCU will automatically add more levels to the
+tree.
+For example, if you are crazy enough to build a 64-bit system with 65,536
+CPUs, RCU would configure the <tt>rcu_node</tt> tree as follows:
+
+</p><p><img src="HugeTreeClassicRCU.svg" alt="HugeTreeClassicRCU.svg" width="50%">
+
+</p><p>RCU currently permits up to a four-level tree, which on a 64-bit system
+accommodates up to 4,194,304 CPUs, though only a mere 524,288 CPUs for
+32-bit systems.
+On the other hand, you can set <tt>CONFIG_RCU_FANOUT</tt> to be
+as small as 2 if you wish, which would permit only 16 CPUs, which
+is useful for testing.
+
+</p><p>This multi-level combining tree allows us to get most of the
+performance and scalability
+benefits of partitioning, even though RCU grace-period detection is
+inherently a global operation.
+The trick here is that only the last CPU to report a quiescent state
+into a given <tt>rcu_node</tt> structure need advance to the <tt>rcu_node</tt>
+structure at the next level up the tree.
+This means that at the leaf-level <tt>rcu_node</tt> structure, only
+one access out of sixteen will progress up the tree.
+For the internal <tt>rcu_node</tt> structures, the situation is even
+more extreme:  Only one access out of sixty-four will progress up
+the tree.
+Because the vast majority of the CPUs do not progress up the tree,
+the lock contention remains roughly constant up the tree.
+No matter how many CPUs there are in the system, at most 64 quiescent-state
+reports per grace period will progress all the way to the root
+<tt>rcu_node</tt> structure, thus ensuring that the lock contention
+on that root <tt>rcu_node</tt> structure remains acceptably low.
+
+</p><p>In effect, the combining tree acts like a big shock absorber,
+keeping lock contention under control at all tree levels regardless
+of the level of loading on the system.
+
+</p><p>The Linux kernel actually supports multiple flavors of RCU
+running concurrently, so RCU builds separate data structures for each
+flavor.
+For example, for <tt>CONFIG_TREE_RCU=y</tt> kernels, RCU provides
+rcu_sched and rcu_bh, as shown below:
+
+</p><p><img src="BigTreeClassicRCUBH.svg" alt="BigTreeClassicRCUBH.svg" width="33%">
+
+</p><p>Energy efficiency is increasingly important, and for that
+reason the Linux kernel provides <tt>CONFIG_NO_HZ_IDLE</tt>, which
+turns off the scheduling-clock interrupts on idle CPUs, which in
+turn allows those CPUs to attain deeper sleep states and to consume
+less energy.
+CPUs whose scheduling-clock interrupts have been turned off are
+said to be in <i>dyntick-idle mode</i>.
+RCU must handle dyntick-idle CPUs specially
+because RCU would otherwise wake up each CPU on every grace period,
+which would defeat the whole purpose of <tt>CONFIG_NO_HZ_IDLE</tt>.
+RCU uses the <tt>rcu_dynticks</tt> structure to track
+which CPUs are in dyntick idle mode, as shown below:
+
+</p><p><img src="BigTreeClassicRCUBHdyntick.svg" alt="BigTreeClassicRCUBHdyntick.svg" width="33%">
+
+</p><p>However, if a CPU is in dyntick-idle mode, it is in that mode
+for all flavors of RCU.
+Therefore, a single <tt>rcu_dynticks</tt> structure is allocated per
+CPU, and all of a given CPU's <tt>rcu_data</tt> structures share
+that <tt>rcu_dynticks</tt>, as shown in the figure.
+
+</p><p>Kernels built with <tt>CONFIG_PREEMPT_RCU</tt> support
+rcu_preempt in addition to rcu_sched and rcu_bh, as shown below:
+
+</p><p><img src="BigTreePreemptRCUBHdyntick.svg" alt="BigTreePreemptRCUBHdyntick.svg" width="35%">
+
+</p><p>RCU updaters wait for normal grace periods by registering
+RCU callbacks, either directly via <tt>call_rcu()</tt> and
+friends (namely <tt>call_rcu_bh()</tt> and <tt>call_rcu_sched()</tt>),
+there being a separate interface per flavor of RCU)
+or indirectly via <tt>synchronize_rcu()</tt> and friends.
+RCU callbacks are represented by <tt>rcu_head</tt> structures,
+which are queued on <tt>rcu_data</tt> structures while they are
+waiting for a grace period to elapse, as shown in the following figure:
+
+</p><p><img src="BigTreePreemptRCUBHdyntickCB.svg" alt="BigTreePreemptRCUBHdyntickCB.svg" width="40%">
+
+</p><p>This figure shows how <tt>TREE_RCU</tt>'s and
+<tt>PREEMPT_RCU</tt>'s major data structures are related.
+Lesser data structures will be introduced with the algorithms that
+make use of them.
+
+</p><p>Note that each of the data structures in the above figure has
+its own synchronization:
+
+<p><ol>
+<li>	Each <tt>rcu_state</tt> structures has a lock and a mutex,
+	and some fields are protected by the corresponding root
+	<tt>rcu_node</tt> structure's lock.
+<li>	Each <tt>rcu_node</tt> structure has a spinlock.
+<li>	The fields in <tt>rcu_data</tt> are private to the corresponding
+	CPU, although a few can be read and written by other CPUs.
+<li>	Similarly, the fields in <tt>rcu_dynticks</tt> are private
+	to the corresponding CPU, although a few can be read by
+	other CPUs.
+</ol>
+
+<p>It is important to note that different data structures can have
+very different ideas about the state of RCU at any given time.
+For but one example, awareness of the start or end of a given RCU
+grace period propagates slowly through the data structures.
+This slow propagation is absolutely necessary for RCU to have good
+read-side performance.
+If this balkanized implementation seems foreign to you, one useful
+trick is to consider each instance of these data structures to be
+a different person, each having the usual slightly different
+view of reality.
+
+</p><p>The general role of each of these data structures is as
+follows:
+
+</p><ol>
+<li>	<tt>rcu_state</tt>:
+	This structure forms the interconnection between the
+	<tt>rcu_node</tt> and <tt>rcu_data</tt> structures,
+	tracks grace periods, serves as short-term repository
+	for callbacks orphaned by CPU-hotplug events,
+	maintains <tt>rcu_barrier()</tt> state,
+	tracks expedited grace-period state,
+	and maintains state used to force quiescent states when
+	grace periods extend too long,
+<li>	<tt>rcu_node</tt>: This structure forms the combining
+	tree that propagates quiescent-state
+	information from the leaves to the root, and also propagates
+	grace-period information from the root to the leaves.
+	It provides local copies of the grace-period state in order
+	to allow this information to be accessed in a synchronized
+	manner without suffering the scalability limitations that
+	would otherwise be imposed by global locking.
+	In <tt>CONFIG_PREEMPT_RCU</tt> kernels, it manages the lists
+	of tasks that have blocked while in their current
+	RCU read-side critical section.
+	In <tt>CONFIG_PREEMPT_RCU</tt> with
+	<tt>CONFIG_RCU_BOOST</tt>, it manages the
+	per-<tt>rcu_node</tt> priority-boosting
+	kernel threads (kthreads) and state.
+	Finally, it records CPU-hotplug state in order to determine
+	which CPUs should be ignored during a given grace period.
+<li>	<tt>rcu_data</tt>: This per-CPU structure is the
+	focus of quiescent-state detection and RCU callback queuing.
+	It also tracks its relationship to the corresponding leaf
+	<tt>rcu_node</tt> structure to allow more-efficient
+	propagation of quiescent states up the <tt>rcu_node</tt>
+	combining tree.
+	Like the <tt>rcu_node</tt> structure, it provides a local
+	copy of the grace-period information to allow for-free
+	synchronized
+	access to this information from the corresponding CPU.
+	Finally, this structure records past dyntick-idle state
+	for the corresponding CPU and also tracks statistics.
+<li>	<tt>rcu_dynticks</tt>:
+	This per-CPU structure tracks the current dyntick-idle
+	state for the corresponding CPU.
+	Unlike the other three structures, the <tt>rcu_dynticks</tt>
+	structure is not replicated per RCU flavor.
+<li>	<tt>rcu_head</tt>:
+	This structure represents RCU callbacks, and is the
+	only structure allocated and managed by RCU users.
+	The <tt>rcu_head</tt> structure is normally embedded
+	within the RCU-protected data structure.
+</ol>
+
+<p>If all you wanted from this article was a general notion of how
+RCU's data structures are related, you are done.
+Otherwise, each of the following sections give more details on
+the <tt>rcu_state</tt>, <tt>rcu_node</tt>, <tt>rcu_data</tt>,
+and <tt>rcu_dynticks</tt> data structures.
+
+<h3><a name="The rcu_state Structure">
+The <tt>rcu_state</tt> Structure</a></h3>
+
+<p>The <tt>rcu_state</tt> structure is the base structure that
+represents a flavor of RCU.
+This structure forms the interconnection between the
+<tt>rcu_node</tt> and <tt>rcu_data</tt> structures,
+tracks grace periods, contains the lock used to
+synchronize with CPU-hotplug events,
+and maintains state used to force quiescent states when
+grace periods extend too long,
+
+</p><p>A few of the <tt>rcu_state</tt> structure's fields are discussed,
+singly and in groups, in the following sections.
+The more specialized fields are covered in the discussion of their
+use.
+
+<h5>Relationship to rcu_node and rcu_data Structures</h5>
+
+This portion of the <tt>rcu_state</tt> structure is declared
+as follows:
+
+<pre>
+  1   struct rcu_node node[NUM_RCU_NODES];
+  2   struct rcu_node *level[NUM_RCU_LVLS + 1];
+  3   struct rcu_data __percpu *rda;
+</pre>
+
+<table>
+<tr><th>&nbsp;</th></tr>
+<tr><th align="left">Quick Quiz:</th></tr>
+<tr><td>
+	Wait a minute!
+	You said that the <tt>rcu_node</tt> structures formed a tree,
+	but they are declared as a flat array!
+	What gives?
+</td></tr>
+<tr><th align="left">Answer:</th></tr>
+<tr><td bgcolor="#ffffff"><font color="ffffff">
+	The tree is laid out in the array.
+	The first node In the array is the head, the next set of nodes in the
+	array are children of the head node, and so on until the last set of
+	nodes in the array are the leaves.
+	</font>
+
+	<p><font color="ffffff">See the following diagrams to see how
+	this works.
+</font></td></tr>
+<tr><td>&nbsp;</td></tr>
+</table>
+
+<p>The <tt>rcu_node</tt> tree is embedded into the
+<tt>-&gt;node[]</tt> array as shown in the following figure:
+
+</p><p><img src="TreeMapping.svg" alt="TreeMapping.svg" width="40%">
+
+</p><p>One interesting consequence of this mapping is that a
+breadth-first traversal of the tree is implemented as a simple
+linear scan of the array, which is in fact what the
+<tt>rcu_for_each_node_breadth_first()</tt> macro does.
+This macro is used at the beginning and ends of grace periods.
+
+</p><p>Each entry of the <tt>-&gt;level</tt> array references
+the first <tt>rcu_node</tt> structure on the corresponding level
+of the tree, for example, as shown below:
+
+</p><p><img src="TreeMappingLevel.svg" alt="TreeMappingLevel.svg" width="40%">
+
+</p><p>The zero<sup>th</sup> element of the array references the root
+<tt>rcu_node</tt> structure, the first element references the
+first child of the root <tt>rcu_node</tt>, and finally the second
+element references the first leaf <tt>rcu_node</tt> structure.
+
+</p><p>For whatever it is worth, if you draw the tree to be tree-shaped
+rather than array-shaped, it is easy to draw a planar representation:
+
+</p><p><img src="TreeLevel.svg" alt="TreeLevel.svg" width="60%">
+
+</p><p>Finally, the <tt>-&gt;rda</tt> field references a per-CPU
+pointer to the corresponding CPU's <tt>rcu_data</tt> structure.
+
+</p><p>All of these fields are constant once initialization is complete,
+and therefore need no protection.
+
+<h5>Grace-Period Tracking</h5>
+
+<p>This portion of the <tt>rcu_state</tt> structure is declared
+as follows:
+
+<pre>
+  1   unsigned long gpnum;
+  2   unsigned long completed;
+</pre>
+
+<p>RCU grace periods are numbered, and
+the <tt>-&gt;gpnum</tt> field contains the number of the grace
+period that started most recently.
+The <tt>-&gt;completed</tt> field contains the number of the
+grace period that completed most recently.
+If the two fields are equal, the RCU grace period that most recently
+started has already completed, and therefore the corresponding
+flavor of RCU is idle.
+If <tt>-&gt;gpnum</tt> is one greater than <tt>-&gt;completed</tt>,
+then <tt>-&gt;gpnum</tt> gives the number of the current RCU
+grace period, which has not yet completed.
+Any other combination of values indicates that something is broken.
+These two fields are protected by the root <tt>rcu_node</tt>'s
+<tt>-&gt;lock</tt> field.
+
+</p><p>There are <tt>-&gt;gpnum</tt> and <tt>-&gt;completed</tt> fields
+in the <tt>rcu_node</tt> and <tt>rcu_data</tt> structures
+as well.
+The fields in the <tt>rcu_state</tt> structure represent the
+most current values, and those of the other structures are compared
+in order to detect the start of a new grace period in a distributed
+fashion.
+The values flow from <tt>rcu_state</tt> to <tt>rcu_node</tt>
+(down the tree from the root to the leaves) to <tt>rcu_data</tt>.
+
+<h5>Miscellaneous</h5>
+
+<p>This portion of the <tt>rcu_state</tt> structure is declared
+as follows:
+
+<pre>
+  1   unsigned long gp_max;
+  2   char abbr;
+  3   char *name;
+</pre>
+
+<p>The <tt>-&gt;gp_max</tt> field tracks the duration of the longest
+grace period in jiffies.
+It is protected by the root <tt>rcu_node</tt>'s <tt>-&gt;lock</tt>.
+
+<p>The <tt>-&gt;name</tt> field points to the name of the RCU flavor
+(for example, &ldquo;rcu_sched&rdquo;), and is constant.
+The <tt>-&gt;abbr</tt> field contains a one-character abbreviation,
+for example, &ldquo;s&rdquo; for RCU-sched.
+
+<h3><a name="The rcu_node Structure">
+The <tt>rcu_node</tt> Structure</a></h3>
+
+<p>The <tt>rcu_node</tt> structures form the combining
+tree that propagates quiescent-state
+information from the leaves to the root and also that propagates
+grace-period information from the root down to the leaves.
+They provides local copies of the grace-period state in order
+to allow this information to be accessed in a synchronized
+manner without suffering the scalability limitations that
+would otherwise be imposed by global locking.
+In <tt>CONFIG_PREEMPT_RCU</tt> kernels, they manage the lists
+of tasks that have blocked while in their current
+RCU read-side critical section.
+In <tt>CONFIG_PREEMPT_RCU</tt> with
+<tt>CONFIG_RCU_BOOST</tt>, they manage the
+per-<tt>rcu_node</tt> priority-boosting
+kernel threads (kthreads) and state.
+Finally, they record CPU-hotplug state in order to determine
+which CPUs should be ignored during a given grace period.
+
+</p><p>The <tt>rcu_node</tt> structure's fields are discussed,
+singly and in groups, in the following sections.
+
+<h5>Connection to Combining Tree</h5>
+
+<p>This portion of the <tt>rcu_node</tt> structure is declared
+as follows:
+
+<pre>
+  1   struct rcu_node *parent;
+  2   u8 level;
+  3   u8 grpnum;
+  4   unsigned long grpmask;
+  5   int grplo;
+  6   int grphi;
+</pre>
+
+<p>The <tt>-&gt;parent</tt> pointer references the <tt>rcu_node</tt>
+one level up in the tree, and is <tt>NULL</tt> for the root
+<tt>rcu_node</tt>.
+The RCU implementation makes heavy use of this field to push quiescent
+states up the tree.
+The <tt>-&gt;level</tt> field gives the level in the tree, with
+the root being at level zero, its children at level one, and so on.
+The <tt>-&gt;grpnum</tt> field gives this node's position within
+the children of its parent, so this number can range between 0 and 31
+on 32-bit systems and between 0 and 63 on 64-bit systems.
+The <tt>-&gt;level</tt> and <tt>-&gt;grpnum</tt> fields are
+used only during initialization and for tracing.
+The <tt>-&gt;grpmask</tt> field is the bitmask counterpart of
+<tt>-&gt;grpnum</tt>, and therefore always has exactly one bit set.
+This mask is used to clear the bit corresponding to this <tt>rcu_node</tt>
+structure in its parent's bitmasks, which are described later.
+Finally, the <tt>-&gt;grplo</tt> and <tt>-&gt;grphi</tt> fields
+contain the lowest and highest numbered CPU served by this
+<tt>rcu_node</tt> structure, respectively.
+
+</p><p>All of these fields are constant, and thus do not require any
+synchronization.
+
+<h5>Synchronization</h5>
+
+<p>This field of the <tt>rcu_node</tt> structure is declared
+as follows:
+
+<pre>
+  1   raw_spinlock_t lock;
+</pre>
+
+<p>This field is used to protect the remaining fields in this structure,
+unless otherwise stated.
+That said, all of the fields in this structure can be accessed without
+locking for tracing purposes.
+Yes, this can result in confusing traces, but better some tracing confusion
+than to be heisenbugged out of existence.
+
+<h5>Grace-Period Tracking</h5>
+
+<p>This portion of the <tt>rcu_node</tt> structure is declared
+as follows:
+
+<pre>
+  1   unsigned long gpnum;
+  2   unsigned long completed;
+</pre>
+
+<p>These fields are the counterparts of the fields of the same name in
+the <tt>rcu_state</tt> structure.
+They each may lag up to one behind their <tt>rcu_state</tt>
+counterparts.
+If a given <tt>rcu_node</tt> structure's <tt>-&gt;gpnum</tt> and
+<tt>-&gt;complete</tt> fields are equal, then this <tt>rcu_node</tt>
+structure believes that RCU is idle.
+Otherwise, as with the <tt>rcu_state</tt> structure,
+the <tt>-&gt;gpnum</tt> field will be one greater than the
+<tt>-&gt;complete</tt> fields, with <tt>-&gt;gpnum</tt>
+indicating which grace period this <tt>rcu_node</tt> believes
+is still being waited for.
+
+</p><p>The <tt>&gt;gpnum</tt> field of each <tt>rcu_node</tt>
+structure is updated at the beginning
+of each grace period, and the <tt>-&gt;completed</tt> fields are
+updated at the end of each grace period.
+
+<h5>Quiescent-State Tracking</h5>
+
+<p>These fields manage the propagation of quiescent states up the
+combining tree.
+
+</p><p>This portion of the <tt>rcu_node</tt> structure has fields
+as follows:
+
+<pre>
+  1   unsigned long qsmask;
+  2   unsigned long expmask;
+  3   unsigned long qsmaskinit;
+  4   unsigned long expmaskinit;
+</pre>
+
+<p>The <tt>-&gt;qsmask</tt> field tracks which of this
+<tt>rcu_node</tt> structure's children still need to report
+quiescent states for the current normal grace period.
+Such children will have a value of 1 in their corresponding bit.
+Note that the leaf <tt>rcu_node</tt> structures should be
+thought of as having <tt>rcu_data</tt> structures as their
+children.
+Similarly, the <tt>-&gt;expmask</tt> field tracks which
+of this <tt>rcu_node</tt> structure's children still need to report
+quiescent states for the current expedited grace period.
+An expedited grace period has
+the same conceptual properties as a normal grace period, but the
+expedited implementation accepts extreme CPU overhead to obtain
+much lower grace-period latency, for example, consuming a few
+tens of microseconds worth of CPU time to reduce grace-period
+duration from milliseconds to tens of microseconds.
+The <tt>-&gt;qsmaskinit</tt> field tracks which of this
+<tt>rcu_node</tt> structure's children cover for at least
+one online CPU.
+This mask is used to initialize <tt>-&gt;qsmask</tt>,
+and <tt>-&gt;expmaskinit</tt> is used to initialize
+<tt>-&gt;expmask</tt> and the beginning of the
+normal and expedited grace periods, respectively.
+
+<table>
+<tr><th>&nbsp;</th></tr>
+<tr><th align="left">Quick Quiz:</th></tr>
+<tr><td>
+	Why are these bitmasks protected by locking?
+	Come on, haven't you heard of atomic instructions???
+</td></tr>
+<tr><th align="left">Answer:</th></tr>
+<tr><td bgcolor="#ffffff"><font color="ffffff">
+	Lockless grace-period computation!  Such a tantalizing possibility!
+	</font>
+
+	<p><font color="ffffff">But consider the following sequence of events:
+	</font>
+
+	<ol>
+	<li>	<font color="ffffff">CPU&nbsp;0 has been in dyntick-idle
+		mode for quite some time.
+		When it wakes up, it notices that the current RCU
+		grace period needs it to report in, so it sets a
+		flag where the scheduling clock interrupt will find it.
+		</font><p>
+	<li>	<font color="ffffff">Meanwhile, CPU&nbsp;1 is running
+		<tt>force_quiescent_state()</tt>,
+		and notices that CPU&nbsp;0 has been in dyntick idle mode,
+		which qualifies as an extended quiescent state.
+		</font><p>
+	<li>	<font color="ffffff">CPU&nbsp;0's scheduling clock
+		interrupt fires in the
+		middle of an RCU read-side critical section, and notices
+		that the RCU core needs something, so commences RCU softirq
+		processing.
+		</font>
+		<p>
+	<li>	<font color="ffffff">CPU&nbsp;0's softirq handler
+		executes and is just about ready
+		to report its quiescent state up the <tt>rcu_node</tt>
+		tree.
+		</font><p>
+	<li>	<font color="ffffff">But CPU&nbsp;1 beats it to the punch,
+		completing the current
+		grace period and starting a new one.
+		</font><p>
+	<li>	<font color="ffffff">CPU&nbsp;0 now reports its quiescent
+		state for the wrong
+		grace period.
+		That grace period might now end before the RCU read-side
+		critical section.
+		If that happens, disaster will ensue.
+		</font>
+	</ol>
+
+	<p><font color="ffffff">So the locking is absolutely required in
+	order to coordinate
+	clearing of the bits with the grace-period numbers in
+	<tt>-&gt;gpnum</tt> and <tt>-&gt;completed</tt>.
+</font></td></tr>
+<tr><td>&nbsp;</td></tr>
+</table>
+
+<h5>Blocked-Task Management</h5>
+
+<p><tt>PREEMPT_RCU</tt> allows tasks to be preempted in the
+midst of their RCU read-side critical sections, and these tasks
+must be tracked explicitly.
+The details of exactly why and how they are tracked will be covered
+in a separate article on RCU read-side processing.
+For now, it is enough to know that the <tt>rcu_node</tt>
+structure tracks them.
+
+<pre>
+  1   struct list_head blkd_tasks;
+  2   struct list_head *gp_tasks;
+  3   struct list_head *exp_tasks;
+  4   bool wait_blkd_tasks;
+</pre>
+
+<p>The <tt>-&gt;blkd_tasks</tt> field is a list header for
+the list of blocked and preempted tasks.
+As tasks undergo context switches within RCU read-side critical
+sections, their <tt>task_struct</tt> structures are enqueued
+(via the <tt>task_struct</tt>'s <tt>-&gt;rcu_node_entry</tt>
+field) onto the head of the <tt>-&gt;blkd_tasks</tt> list for the
+leaf <tt>rcu_node</tt> structure corresponding to the CPU
+on which the outgoing context switch executed.
+As these tasks later exit their RCU read-side critical sections,
+they remove themselves from the list.
+This list is therefore in reverse time order, so that if one of the tasks
+is blocking the current grace period, all subsequent tasks must
+also be blocking that same grace period.
+Therefore, a single pointer into this list suffices to track
+all tasks blocking a given grace period.
+That pointer is stored in <tt>-&gt;gp_tasks</tt> for normal
+grace periods and in <tt>-&gt;exp_tasks</tt> for expedited
+grace periods.
+These last two fields are <tt>NULL</tt> if either there is
+no grace period in flight or if there are no blocked tasks
+preventing that grace period from completing.
+If either of these two pointers is referencing a task that
+removes itself from the <tt>-&gt;blkd_tasks</tt> list,
+then that task must advance the pointer to the next task on
+the list, or set the pointer to <tt>NULL</tt> if there
+are no subsequent tasks on the list.
+
+</p><p>For example, suppose that tasks&nbsp;T1, T2, and&nbsp;T3 are
+all hard-affinitied to the largest-numbered CPU in the system.
+Then if task&nbsp;T1 blocked in an RCU read-side
+critical section, then an expedited grace period started,
+then task&nbsp;T2 blocked in an RCU read-side critical section,
+then a normal grace period started, and finally task&nbsp;3 blocked
+in an RCU read-side critical section, then the state of the
+last leaf <tt>rcu_node</tt> structure's blocked-task list
+would be as shown below:
+
+</p><p><img src="blkd_task.svg" alt="blkd_task.svg" width="60%">
+
+</p><p>Task&nbsp;T1 is blocking both grace periods, task&nbsp;T2 is
+blocking only the normal grace period, and task&nbsp;T3 is blocking
+neither grace period.
+Note that these tasks will not remove themselves from this list
+immediately upon resuming execution.
+They will instead remain on the list until they execute the outermost
+<tt>rcu_read_unlock()</tt> that ends their RCU read-side critical
+section.
+
+<p>
+The <tt>-&gt;wait_blkd_tasks</tt> field indicates whether or not
+the current grace period is waiting on a blocked task.
+
+<h5>Sizing the <tt>rcu_node</tt> Array</h5>
+
+<p>The <tt>rcu_node</tt> array is sized via a series of
+C-preprocessor expressions as follows:
+
+<pre>
+ 1 #ifdef CONFIG_RCU_FANOUT
+ 2 #define RCU_FANOUT CONFIG_RCU_FANOUT
+ 3 #else
+ 4 # ifdef CONFIG_64BIT
+ 5 # define RCU_FANOUT 64
+ 6 # else
+ 7 # define RCU_FANOUT 32
+ 8 # endif
+ 9 #endif
+10
+11 #ifdef CONFIG_RCU_FANOUT_LEAF
+12 #define RCU_FANOUT_LEAF CONFIG_RCU_FANOUT_LEAF
+13 #else
+14 # ifdef CONFIG_64BIT
+15 # define RCU_FANOUT_LEAF 64
+16 # else
+17 # define RCU_FANOUT_LEAF 32
+18 # endif
+19 #endif
+20
+21 #define RCU_FANOUT_1        (RCU_FANOUT_LEAF)
+22 #define RCU_FANOUT_2        (RCU_FANOUT_1 * RCU_FANOUT)
+23 #define RCU_FANOUT_3        (RCU_FANOUT_2 * RCU_FANOUT)
+24 #define RCU_FANOUT_4        (RCU_FANOUT_3 * RCU_FANOUT)
+25
+26 #if NR_CPUS &lt;= RCU_FANOUT_1
+27 #  define RCU_NUM_LVLS        1
+28 #  define NUM_RCU_LVL_0        1
+29 #  define NUM_RCU_NODES        NUM_RCU_LVL_0
+30 #  define NUM_RCU_LVL_INIT    { NUM_RCU_LVL_0 }
+31 #  define RCU_NODE_NAME_INIT  { "rcu_node_0" }
+32 #  define RCU_FQS_NAME_INIT   { "rcu_node_fqs_0" }
+33 #  define RCU_EXP_NAME_INIT   { "rcu_node_exp_0" }
+34 #elif NR_CPUS &lt;= RCU_FANOUT_2
+35 #  define RCU_NUM_LVLS        2
+36 #  define NUM_RCU_LVL_0        1
+37 #  define NUM_RCU_LVL_1        DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1)
+38 #  define NUM_RCU_NODES        (NUM_RCU_LVL_0 + NUM_RCU_LVL_1)
+39 #  define NUM_RCU_LVL_INIT    { NUM_RCU_LVL_0, NUM_RCU_LVL_1 }
+40 #  define RCU_NODE_NAME_INIT  { "rcu_node_0", "rcu_node_1" }
+41 #  define RCU_FQS_NAME_INIT   { "rcu_node_fqs_0", "rcu_node_fqs_1" }
+42 #  define RCU_EXP_NAME_INIT   { "rcu_node_exp_0", "rcu_node_exp_1" }
+43 #elif NR_CPUS &lt;= RCU_FANOUT_3
+44 #  define RCU_NUM_LVLS        3
+45 #  define NUM_RCU_LVL_0        1
+46 #  define NUM_RCU_LVL_1        DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_2)
+47 #  define NUM_RCU_LVL_2        DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1)
+48 #  define NUM_RCU_NODES        (NUM_RCU_LVL_0 + NUM_RCU_LVL_1 + NUM_RCU_LVL_2)
+49 #  define NUM_RCU_LVL_INIT    { NUM_RCU_LVL_0, NUM_RCU_LVL_1, NUM_RCU_LVL_2 }
+50 #  define RCU_NODE_NAME_INIT  { "rcu_node_0", "rcu_node_1", "rcu_node_2" }
+51 #  define RCU_FQS_NAME_INIT   { "rcu_node_fqs_0", "rcu_node_fqs_1", "rcu_node_fqs_2" }
+52 #  define RCU_EXP_NAME_INIT   { "rcu_node_exp_0", "rcu_node_exp_1", "rcu_node_exp_2" }
+53 #elif NR_CPUS &lt;= RCU_FANOUT_4
+54 #  define RCU_NUM_LVLS        4
+55 #  define NUM_RCU_LVL_0        1
+56 #  define NUM_RCU_LVL_1        DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_3)
+57 #  define NUM_RCU_LVL_2        DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_2)
+58 #  define NUM_RCU_LVL_3        DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1)
+59 #  define NUM_RCU_NODES        (NUM_RCU_LVL_0 + NUM_RCU_LVL_1 + NUM_RCU_LVL_2 + NUM_RCU_LVL_3)
+60 #  define NUM_RCU_LVL_INIT    { NUM_RCU_LVL_0, NUM_RCU_LVL_1, NUM_RCU_LVL_2, NUM_RCU_LVL_3 }
+61 #  define RCU_NODE_NAME_INIT  { "rcu_node_0", "rcu_node_1", "rcu_node_2", "rcu_node_3" }
+62 #  define RCU_FQS_NAME_INIT   { "rcu_node_fqs_0", "rcu_node_fqs_1", "rcu_node_fqs_2", "rcu_node_fqs_3" }
+63 #  define RCU_EXP_NAME_INIT   { "rcu_node_exp_0", "rcu_node_exp_1", "rcu_node_exp_2", "rcu_node_exp_3" }
+64 #else
+65 # error "CONFIG_RCU_FANOUT insufficient for NR_CPUS"
+66 #endif
+</pre>
+
+<p>The maximum number of levels in the <tt>rcu_node</tt> structure
+is currently limited to four, as specified by lines&nbsp;21-24
+and the structure of the subsequent &ldquo;if&rdquo; statement.
+For 32-bit systems, this allows 16*32*32*32=524,288 CPUs, which
+should be sufficient for the next few years at least.
+For 64-bit systems, 16*64*64*64=4,194,304 CPUs is allowed, which
+should see us through the next decade or so.
+This four-level tree also allows kernels built with
+<tt>CONFIG_RCU_FANOUT=8</tt> to support up to 4096 CPUs,
+which might be useful in very large systems having eight CPUs per
+socket (but please note that no one has yet shown any measurable
+performance degradation due to misaligned socket and <tt>rcu_node</tt>
+boundaries).
+In addition, building kernels with a full four levels of <tt>rcu_node</tt>
+tree permits better testing of RCU's combining-tree code.
+
+</p><p>The <tt>RCU_FANOUT</tt> symbol controls how many children
+are permitted at each non-leaf level of the <tt>rcu_node</tt> tree.
+If the <tt>CONFIG_RCU_FANOUT</tt> Kconfig option is not specified,
+it is set based on the word size of the system, which is also
+the Kconfig default.
+
+</p><p>The <tt>RCU_FANOUT_LEAF</tt> symbol controls how many CPUs are
+handled by each leaf <tt>rcu_node</tt> structure.
+Experience has shown that allowing a given leaf <tt>rcu_node</tt>
+structure to handle 64 CPUs, as permitted by the number of bits in
+the <tt>-&gt;qsmask</tt> field on a 64-bit system, results in
+excessive contention for the leaf <tt>rcu_node</tt> structures'
+<tt>-&gt;lock</tt> fields.
+The number of CPUs per leaf <tt>rcu_node</tt> structure is therefore
+limited to 16 given the default value of <tt>CONFIG_RCU_FANOUT_LEAF</tt>.
+If <tt>CONFIG_RCU_FANOUT_LEAF</tt> is unspecified, the value
+selected is based on the word size of the system, just as for
+<tt>CONFIG_RCU_FANOUT</tt>.
+Lines&nbsp;11-19 perform this computation.
+
+</p><p>Lines&nbsp;21-24 compute the maximum number of CPUs supported by
+a single-level (which contains a single <tt>rcu_node</tt> structure),
+two-level, three-level, and four-level <tt>rcu_node</tt> tree,
+respectively, given the fanout specified by <tt>RCU_FANOUT</tt>
+and <tt>RCU_FANOUT_LEAF</tt>.
+These numbers of CPUs are retained in the
+<tt>RCU_FANOUT_1</tt>,
+<tt>RCU_FANOUT_2</tt>,
+<tt>RCU_FANOUT_3</tt>, and
+<tt>RCU_FANOUT_4</tt>
+C-preprocessor variables, respectively.
+
+</p><p>These variables are used to control the C-preprocessor <tt>#if</tt>
+statement spanning lines&nbsp;26-66 that computes the number of
+<tt>rcu_node</tt> structures required for each level of the tree,
+as well as the number of levels required.
+The number of levels is placed in the <tt>NUM_RCU_LVLS</tt>
+C-preprocessor variable by lines&nbsp;27, 35, 44, and&nbsp;54.
+The number of <tt>rcu_node</tt> structures for the topmost level
+of the tree is always exactly one, and this value is unconditionally
+placed into <tt>NUM_RCU_LVL_0</tt> by lines&nbsp;28, 36, 45, and&nbsp;55.
+The rest of the levels (if any) of the <tt>rcu_node</tt> tree
+are computed by dividing the maximum number of CPUs by the
+fanout supported by the number of levels from the current level down,
+rounding up.  This computation is performed by lines&nbsp;37,
+46-47, and&nbsp;56-58.
+Lines&nbsp;31-33, 40-42, 50-52, and&nbsp;62-63 create initializers
+for lockdep lock-class names.
+Finally, lines&nbsp;64-66 produce an error if the maximum number of
+CPUs is too large for the specified fanout.
+
+<h3><a name="The rcu_data Structure">
+The <tt>rcu_data</tt> Structure</a></h3>
+
+<p>The <tt>rcu_data</tt> maintains the per-CPU state for the
+corresponding flavor of RCU.
+The fields in this structure may be accessed only from the corresponding
+CPU (and from tracing) unless otherwise stated.
+This structure is the
+focus of quiescent-state detection and RCU callback queuing.
+It also tracks its relationship to the corresponding leaf
+<tt>rcu_node</tt> structure to allow more-efficient
+propagation of quiescent states up the <tt>rcu_node</tt>
+combining tree.
+Like the <tt>rcu_node</tt> structure, it provides a local
+copy of the grace-period information to allow for-free
+synchronized
+access to this information from the corresponding CPU.
+Finally, this structure records past dyntick-idle state
+for the corresponding CPU and also tracks statistics.
+
+</p><p>The <tt>rcu_data</tt> structure's fields are discussed,
+singly and in groups, in the following sections.
+
+<h5>Connection to Other Data Structures</h5>
+
+<p>This portion of the <tt>rcu_data</tt> structure is declared
+as follows:
+
+<pre>
+  1   int cpu;
+  2   struct rcu_state *rsp;
+  3   struct rcu_node *mynode;
+  4   struct rcu_dynticks *dynticks;
+  5   unsigned long grpmask;
+  6   bool beenonline;
+</pre>
+
+<p>The <tt>-&gt;cpu</tt> field contains the number of the
+corresponding CPU, the <tt>-&gt;rsp</tt> pointer references
+the corresponding <tt>rcu_state</tt> structure (and is most frequently
+used to locate the name of the corresponding flavor of RCU for tracing),
+and the <tt>-&gt;mynode</tt> field references the corresponding
+<tt>rcu_node</tt> structure.
+The <tt>-&gt;mynode</tt> is used to propagate quiescent states
+up the combining tree.
+<p>The <tt>-&gt;dynticks</tt> pointer references the
+<tt>rcu_dynticks</tt> structure corresponding to this
+CPU.
+Recall that a single per-CPU instance of the <tt>rcu_dynticks</tt>
+structure is shared among all flavors of RCU.
+These first four fields are constant and therefore require not
+synchronization.
+
+</p><p>The <tt>-&gt;grpmask</tt> field indicates the bit in
+the <tt>-&gt;mynode-&gt;qsmask</tt> corresponding to this
+<tt>rcu_data</tt> structure, and is also used when propagating
+quiescent states.
+The <tt>-&gt;beenonline</tt> flag is set whenever the corresponding
+CPU comes online, which means that the debugfs tracing need not dump
+out any <tt>rcu_data</tt> structure for which this flag is not set.
+
+<h5>Quiescent-State and Grace-Period Tracking</h5>
+
+<p>This portion of the <tt>rcu_data</tt> structure is declared
+as follows:
+
+<pre>
+  1   unsigned long completed;
+  2   unsigned long gpnum;
+  3   bool cpu_no_qs;
+  4   bool core_needs_qs;
+  5   bool gpwrap;
+  6   unsigned long rcu_qs_ctr_snap;
+</pre>
+
+<p>The <tt>completed</tt> and <tt>gpnum</tt>
+fields are the counterparts of the fields of the same name
+in the <tt>rcu_state</tt> and <tt>rcu_node</tt> structures.
+They may each lag up to one behind their <tt>rcu_node</tt>
+counterparts, but in <tt>CONFIG_NO_HZ_IDLE</tt> and
+<tt>CONFIG_NO_HZ_FULL</tt> kernels can lag
+arbitrarily far behind for CPUs in dyntick-idle mode (but these counters
+will catch up upon exit from dyntick-idle mode).
+If a given <tt>rcu_data</tt> structure's <tt>-&gt;gpnum</tt> and
+<tt>-&gt;complete</tt> fields are equal, then this <tt>rcu_data</tt>
+structure believes that RCU is idle.
+Otherwise, as with the <tt>rcu_state</tt> and <tt>rcu_node</tt>
+structure,
+the <tt>-&gt;gpnum</tt> field will be one greater than the
+<tt>-&gt;complete</tt> fields, with <tt>-&gt;gpnum</tt>
+indicating which grace period this <tt>rcu_data</tt> believes
+is still being waited for.
+
+<table>
+<tr><th>&nbsp;</th></tr>
+<tr><th align="left">Quick Quiz:</th></tr>
+<tr><td>
+	All this replication of the grace period numbers can only cause
+	massive confusion.
+	Why not just keep a global pair of counters and be done with it???
+</td></tr>
+<tr><th align="left">Answer:</th></tr>
+<tr><td bgcolor="#ffffff"><font color="ffffff">
+	Because if there was only a single global pair of grace-period
+	numbers, there would need to be a single global lock to allow
+	safely accessing and updating them.
+	And if we are not going to have a single global lock, we need
+	to carefully manage the numbers on a per-node basis.
+	Recall from the answer to a previous Quick Quiz that the consequences
+	of applying a previously sampled quiescent state to the wrong
+	grace period are quite severe.
+</font></td></tr>
+<tr><td>&nbsp;</td></tr>
+</table>
+
+<p>The <tt>-&gt;cpu_no_qs</tt> flag indicates that the
+CPU has not yet passed through a quiescent state,
+while the <tt>-&gt;core_needs_qs</tt> flag indicates that the
+RCU core needs a quiescent state from the corresponding CPU.
+The <tt>-&gt;gpwrap</tt> field indicates that the corresponding
+CPU has remained idle for so long that the <tt>completed</tt>
+and <tt>gpnum</tt> counters are in danger of overflow, which
+will cause the CPU to disregard the values of its counters on
+its next exit from idle.
+Finally, the <tt>rcu_qs_ctr_snap</tt> field is used to detect
+cases where a given operation has resulted in a quiescent state
+for all flavors of RCU, for example, <tt>cond_resched_rcu_qs()</tt>.
+
+<h5>RCU Callback Handling</h5>
+
+<p>In the absence of CPU-hotplug events, RCU callbacks are invoked by
+the same CPU that registered them.
+This is strictly a cache-locality optimization: callbacks can and
+do get invoked on CPUs other than the one that registered them.
+After all, if the CPU that registered a given callback has gone
+offline before the callback can be invoked, there really is no other
+choice.
+
+</p><p>This portion of the <tt>rcu_data</tt> structure is declared
+as follows:
+
+<pre>
+ 1 struct rcu_head *nxtlist;
+ 2 struct rcu_head **nxttail[RCU_NEXT_SIZE];
+ 3 unsigned long nxtcompleted[RCU_NEXT_SIZE];
+ 4 long qlen_lazy;
+ 5 long qlen;
+ 6 long qlen_last_fqs_check;
+ 7 unsigned long n_force_qs_snap;
+ 8 unsigned long n_cbs_invoked;
+ 9 unsigned long n_cbs_orphaned;
+10 unsigned long n_cbs_adopted;
+11 long blimit;
+</pre>
+
+<p>The <tt>-&gt;nxtlist</tt> pointer and the
+<tt>-&gt;nxttail[]</tt> array form a four-segment list with
+older callbacks near the head and newer ones near the tail.
+Each segment contains callbacks with the corresponding relationship
+to the current grace period.
+The pointer out of the end of each of the four segments is referenced
+by the element of the <tt>-&gt;nxttail[]</tt> array indexed by
+<tt>RCU_DONE_TAIL</tt> (for callbacks handled by a prior grace period),
+<tt>RCU_WAIT_TAIL</tt> (for callbacks waiting on the current grace period),
+<tt>RCU_NEXT_READY_TAIL</tt> (for callbacks that will wait on the next
+grace period), and
+<tt>RCU_NEXT_TAIL</tt> (for callbacks that are not yet associated
+with a specific grace period)
+respectively, as shown in the following figure.
+
+</p><p><img src="nxtlist.svg" alt="nxtlist.svg" width="40%">
+
+</p><p>In this figure, the <tt>-&gt;nxtlist</tt> pointer references the
+first
+RCU callback in the list.
+The <tt>-&gt;nxttail[RCU_DONE_TAIL]</tt> array element references
+the <tt>-&gt;nxtlist</tt> pointer itself, indicating that none
+of the callbacks is ready to invoke.
+The <tt>-&gt;nxttail[RCU_WAIT_TAIL]</tt> array element references callback
+CB&nbsp;2's <tt>-&gt;next</tt> pointer, which indicates that
+CB&nbsp;1 and CB&nbsp;2 are both waiting on the current grace period.
+The <tt>-&gt;nxttail[RCU_NEXT_READY_TAIL]</tt> array element
+references the same RCU callback that <tt>-&gt;nxttail[RCU_WAIT_TAIL]</tt>
+does, which indicates that there are no callbacks waiting on the next
+RCU grace period.
+The <tt>-&gt;nxttail[RCU_NEXT_TAIL]</tt> array element references
+CB&nbsp;4's <tt>-&gt;next</tt> pointer, indicating that all the
+remaining RCU callbacks have not yet been assigned to an RCU grace
+period.
+Note that the <tt>-&gt;nxttail[RCU_NEXT_TAIL]</tt> array element
+always references the last RCU callback's <tt>-&gt;next</tt> pointer
+unless the callback list is empty, in which case it references
+the <tt>-&gt;nxtlist</tt> pointer.
+
+</p><p>CPUs advance their callbacks from the
+<tt>RCU_NEXT_TAIL</tt> to the <tt>RCU_NEXT_READY_TAIL</tt> to the
+<tt>RCU_WAIT_TAIL</tt> to the <tt>RCU_DONE_TAIL</tt> list segments
+as grace periods advance.
+The CPU advances the callbacks in its <tt>rcu_data</tt> structure
+whenever it notices that another RCU grace period has completed.
+The CPU detects the completion of an RCU grace period by noticing
+that the value of its <tt>rcu_data</tt> structure's
+<tt>-&gt;completed</tt> field differs from that of its leaf
+<tt>rcu_node</tt> structure.
+Recall that each <tt>rcu_node</tt> structure's
+<tt>-&gt;completed</tt> field is updated at the end of each
+grace period.
+
+</p><p>The <tt>-&gt;nxtcompleted[]</tt> array records grace-period
+numbers corresponding to the list segments.
+This allows CPUs that go idle for extended periods to determine
+which of their callbacks are ready to be invoked after reawakening.
+
+</p><p>The <tt>-&gt;qlen</tt> counter contains the number of
+callbacks in <tt>-&gt;nxtlist</tt>, and the
+<tt>-&gt;qlen_lazy</tt> contains the number of those callbacks that
+are known to only free memory, and whose invocation can therefore
+be safely deferred.
+The <tt>-&gt;qlen_last_fqs_check</tt> and
+<tt>-&gt;n_force_qs_snap</tt> coordinate the forcing of quiescent
+states from <tt>call_rcu()</tt> and friends when callback
+lists grow excessively long.
+
+</p><p>The <tt>-&gt;n_cbs_invoked</tt>,
+<tt>-&gt;n_cbs_orphaned</tt>, and <tt>-&gt;n_cbs_adopted</tt>
+fields count the number of callbacks invoked,
+sent to other CPUs when this CPU goes offline,
+and received from other CPUs when those other CPUs go offline.
+Finally, the <tt>-&gt;blimit</tt> counter is the maximum number of
+RCU callbacks that may be invoked at a given time.
+
+<h5>Dyntick-Idle Handling</h5>
+
+<p>This portion of the <tt>rcu_data</tt> structure is declared
+as follows:
+
+<pre>
+  1   int dynticks_snap;
+  2   unsigned long dynticks_fqs;
+</pre>
+
+The <tt>-&gt;dynticks_snap</tt> field is used to take a snapshot
+of the corresponding CPU's dyntick-idle state when forcing
+quiescent states, and is therefore accessed from other CPUs.
+Finally, the <tt>-&gt;dynticks_fqs</tt> field is used to
+count the number of times this CPU is determined to be in
+dyntick-idle state, and is used for tracing and debugging purposes.
+
+<h3><a name="The rcu_dynticks Structure">
+The <tt>rcu_dynticks</tt> Structure</a></h3>
+
+<p>The <tt>rcu_dynticks</tt> maintains the per-CPU dyntick-idle state
+for the corresponding CPU.
+Unlike the other structures, <tt>rcu_dynticks</tt> is not
+replicated over the different flavors of RCU.
+The fields in this structure may be accessed only from the corresponding
+CPU (and from tracing) unless otherwise stated.
+Its fields are as follows:
+
+<pre>
+  1   int dynticks_nesting;
+  2   int dynticks_nmi_nesting;
+  3   atomic_t dynticks;
+</pre>
+
+<p>The <tt>-&gt;dynticks_nesting</tt> field counts the
+nesting depth of normal interrupts.
+In addition, this counter is incremented when exiting dyntick-idle
+mode and decremented when entering it.
+This counter can therefore be thought of as counting the number
+of reasons why this CPU cannot be permitted to enter dyntick-idle
+mode, aside from non-maskable interrupts (NMIs).
+NMIs are counted by the <tt>-&gt;dynticks_nmi_nesting</tt>
+field, except that NMIs that interrupt non-dyntick-idle execution
+are not counted.
+
+</p><p>Finally, the <tt>-&gt;dynticks</tt> field counts the corresponding
+CPU's transitions to and from dyntick-idle mode, so that this counter
+has an even value when the CPU is in dyntick-idle mode and an odd
+value otherwise.
+
+<table>
+<tr><th>&nbsp;</th></tr>
+<tr><th align="left">Quick Quiz:</th></tr>
+<tr><td>
+	Why not just count all NMIs?
+	Wouldn't that be simpler and less error prone?
+</td></tr>
+<tr><th align="left">Answer:</th></tr>
+<tr><td bgcolor="#ffffff"><font color="ffffff">
+	It seems simpler only until you think hard about how to go about
+	updating the <tt>rcu_dynticks</tt> structure's
+	<tt>-&gt;dynticks</tt> field.
+</font></td></tr>
+<tr><td>&nbsp;</td></tr>
+</table>
+
+<p>Additional fields are present for some special-purpose
+builds, and are discussed separately.
+
+<h3><a name="The rcu_head Structure">
+The <tt>rcu_head</tt> Structure</a></h3>
+
+<p>Each <tt>rcu_head</tt> structure represents an RCU callback.
+These structures are normally embedded within RCU-protected data
+structures whose algorithms use asynchronous grace periods.
+In contrast, when using algorithms that block waiting for RCU grace periods,
+RCU users need not provide <tt>rcu_head</tt> structures.
+
+</p><p>The <tt>rcu_head</tt> structure has fields as follows:
+
+<pre>
+  1   struct rcu_head *next;
+  2   void (*func)(struct rcu_head *head);
+</pre>
+
+<p>The <tt>-&gt;next</tt> field is used
+to link the <tt>rcu_head</tt> structures together in the
+lists within the <tt>rcu_data</tt> structures.
+The <tt>-&gt;func</tt> field is a pointer to the function
+to be called when the callback is ready to be invoked, and
+this function is passed a pointer to the <tt>rcu_head</tt>
+structure.
+However, <tt>kfree_rcu()</tt> uses the <tt>-&gt;func</tt>
+field to record the offset of the <tt>rcu_head</tt>
+structure within the enclosing RCU-protected data structure.
+
+</p><p>Both of these fields are used internally by RCU.
+From the viewpoint of RCU users, this structure is an
+opaque &ldquo;cookie&rdquo;.
+
+<table>
+<tr><th>&nbsp;</th></tr>
+<tr><th align="left">Quick Quiz:</th></tr>
+<tr><td>
+	Given that the callback function <tt>-&gt;func</tt>
+	is passed a pointer to the <tt>rcu_head</tt> structure,
+	how is that function supposed to find the beginning of the
+	enclosing RCU-protected data structure?
+</td></tr>
+<tr><th align="left">Answer:</th></tr>
+<tr><td bgcolor="#ffffff"><font color="ffffff">
+	In actual practice, there is a separate callback function per
+	type of RCU-protected data structure.
+	The callback function can therefore use the <tt>container_of()</tt>
+	macro in the Linux kernel (or other pointer-manipulation facilities
+	in other software environments) to find the beginning of the
+	enclosing structure.
+</font></td></tr>
+<tr><td>&nbsp;</td></tr>
+</table>
+
+<h3><a name="RCU-Specific Fields in the task_struct Structure">
+RCU-Specific Fields in the <tt>task_struct</tt> Structure</a></h3>
+
+<p>The <tt>CONFIG_PREEMPT_RCU</tt> implementation uses some
+additional fields in the <tt>task_struct</tt> structure:
+
+<pre>
+ 1 #ifdef CONFIG_PREEMPT_RCU
+ 2   int rcu_read_lock_nesting;
+ 3   union rcu_special rcu_read_unlock_special;
+ 4   struct list_head rcu_node_entry;
+ 5   struct rcu_node *rcu_blocked_node;
+ 6 #endif /* #ifdef CONFIG_PREEMPT_RCU */
+ 7 #ifdef CONFIG_TASKS_RCU
+ 8   unsigned long rcu_tasks_nvcsw;
+ 9   bool rcu_tasks_holdout;
+10   struct list_head rcu_tasks_holdout_list;
+11   int rcu_tasks_idle_cpu;
+12 #endif /* #ifdef CONFIG_TASKS_RCU */
+</pre>
+
+<p>The <tt>-&gt;rcu_read_lock_nesting</tt> field records the
+nesting level for RCU read-side critical sections, and
+the <tt>-&gt;rcu_read_unlock_special</tt> field is a bitmask
+that records special conditions that require <tt>rcu_read_unlock()</tt>
+to do additional work.
+The <tt>-&gt;rcu_node_entry</tt> field is used to form lists of
+tasks that have blocked within preemptible-RCU read-side critical
+sections and the <tt>-&gt;rcu_blocked_node</tt> field references
+the <tt>rcu_node</tt> structure whose list this task is a member of,
+or <tt>NULL</tt> if it is not blocked within a preemptible-RCU
+read-side critical section.
+
+<p>The <tt>-&gt;rcu_tasks_nvcsw</tt> field tracks the number of
+voluntary context switches that this task had undergone at the
+beginning of the current tasks-RCU grace period,
+<tt>-&gt;rcu_tasks_holdout</tt> is set if the current tasks-RCU
+grace period is waiting on this task, <tt>-&gt;rcu_tasks_holdout_list</tt>
+is a list element enqueuing this task on the holdout list,
+and <tt>-&gt;rcu_tasks_idle_cpu</tt> tracks which CPU this
+idle task is running, but only if the task is currently running,
+that is, if the CPU is currently idle.
+
+<h3><a name="Accessor Functions">
+Accessor Functions</a></h3>
+
+<p>The following listing shows the
+<tt>rcu_get_root()</tt>, <tt>rcu_for_each_node_breadth_first</tt>,
+<tt>rcu_for_each_nonleaf_node_breadth_first()</tt>, and
+<tt>rcu_for_each_leaf_node()</tt> function and macros:
+
+<pre>
+  1 static struct rcu_node *rcu_get_root(struct rcu_state *rsp)
+  2 {
+  3   return &amp;rsp-&gt;node[0];
+  4 }
+  5
+  6 #define rcu_for_each_node_breadth_first(rsp, rnp) \
+  7   for ((rnp) = &amp;(rsp)-&gt;node[0]; \
+  8        (rnp) &lt; &amp;(rsp)-&gt;node[NUM_RCU_NODES]; (rnp)++)
+  9
+ 10 #define rcu_for_each_nonleaf_node_breadth_first(rsp, rnp) \
+ 11   for ((rnp) = &amp;(rsp)-&gt;node[0]; \
+ 12        (rnp) &lt; (rsp)-&gt;level[NUM_RCU_LVLS - 1]; (rnp)++)
+ 13
+ 14 #define rcu_for_each_leaf_node(rsp, rnp) \
+ 15   for ((rnp) = (rsp)-&gt;level[NUM_RCU_LVLS - 1]; \
+ 16        (rnp) &lt; &amp;(rsp)-&gt;node[NUM_RCU_NODES]; (rnp)++)
+</pre>
+
+<p>The <tt>rcu_get_root()</tt> simply returns a pointer to the
+first element of the specified <tt>rcu_state</tt> structure's
+<tt>-&gt;node[]</tt> array, which is the root <tt>rcu_node</tt>
+structure.
+
+</p><p>As noted earlier, the <tt>rcu_for_each_node_breadth_first()</tt>
+macro takes advantage of the layout of the <tt>rcu_node</tt>
+structures in the <tt>rcu_state</tt> structure's
+<tt>-&gt;node[]</tt> array, performing a breadth-first traversal by
+simply traversing the array in order.
+The <tt>rcu_for_each_nonleaf_node_breadth_first()</tt> macro operates
+similarly, but traverses only the first part of the array, thus excluding
+the leaf <tt>rcu_node</tt> structures.
+Finally, the <tt>rcu_for_each_leaf_node()</tt> macro traverses only
+the last part of the array, thus traversing only the leaf
+<tt>rcu_node</tt> structures.
+
+<table>
+<tr><th>&nbsp;</th></tr>
+<tr><th align="left">Quick Quiz:</th></tr>
+<tr><td>
+	What do <tt>rcu_for_each_nonleaf_node_breadth_first()</tt> and
+	<tt>rcu_for_each_leaf_node()</tt> do if the <tt>rcu_node</tt> tree
+	contains only a single node?
+</td></tr>
+<tr><th align="left">Answer:</th></tr>
+<tr><td bgcolor="#ffffff"><font color="ffffff">
+	In the single-node case,
+	<tt>rcu_for_each_nonleaf_node_breadth_first()</tt> is a no-op
+	and <tt>rcu_for_each_leaf_node()</tt> traverses the single node.
+</font></td></tr>
+<tr><td>&nbsp;</td></tr>
+</table>
+
+<h3><a name="Summary">
+Summary</a></h3>
+
+So each flavor of RCU is represented by an <tt>rcu_state</tt> structure,
+which contains a combining tree of <tt>rcu_node</tt> and
+<tt>rcu_data</tt> structures.
+Finally, in <tt>CONFIG_NO_HZ_IDLE</tt> kernels, each CPU's dyntick-idle
+state is tracked by an <tt>rcu_dynticks</tt> structure.
+
+If you made it this far, you are well prepared to read the code
+walkthroughs in the other articles in this series.
+
+<h3><a name="Acknowledgments">
+Acknowledgments</a></h3>
+
+I owe thanks to Cyrill Gorcunov, Mathieu Desnoyers, Dhaval Giani, Paul
+Turner, Abhishek Srivastava, Matt Kowalczyk, and Serge Hallyn
+for helping me get this document into a more human-readable state.
+
+<h3><a name="Legal Statement">
+Legal Statement</a></h3>
+
+<p>This work represents the view of the author and does not necessarily
+represent the view of IBM.
+
+</p><p>Linux is a registered trademark of Linus Torvalds.
+
+</p><p>Other company, product, and service names may be trademarks or
+service marks of others.
+
+</body></html>
diff --git a/Documentation/RCU/Design/Data-Structures/HugeTreeClassicRCU.svg b/Documentation/RCU/Design/Data-Structures/HugeTreeClassicRCU.svg
new file mode 100644
index 000000000000..2bf12b468206
--- /dev/null
+++ b/Documentation/RCU/Design/Data-Structures/HugeTreeClassicRCU.svg
@@ -0,0 +1,939 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!-- Creator: fig2dev Version 3.2 Patchlevel 5e -->
+
+<!-- CreationDate: Wed Dec  9 17:37:22 2015 -->
+
+<!-- Magnification: 3.000 -->
+
+<svg
+   xmlns:dc="http://purl.org/dc/elements/1.1/"
+   xmlns:cc="http://creativecommons.org/ns#"
+   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+   xmlns:svg="http://www.w3.org/2000/svg"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
+   width="15.1in"
+   height="11.2in"
+   viewBox="-66 -66 18087 13407"
+   id="svg2"
+   version="1.1"
+   inkscape:version="0.48.4 r9939"
+   sodipodi:docname="HugeTreeClassicRCU.fig">
+  <metadata
+     id="metadata224">
+    <rdf:RDF>
+      <cc:Work
+         rdf:about="">
+        <dc:format>image/svg+xml</dc:format>
+        <dc:type
+           rdf:resource="http://purl.org/dc/dcmitype/StillImage" />
+        <dc:title></dc:title>
+      </cc:Work>
+    </rdf:RDF>
+  </metadata>
+  <defs
+     id="defs222">
+    <marker
+       inkscape:stockid="Arrow1Mend"
+       orient="auto"
+       refY="0.0"
+       refX="0.0"
+       id="Arrow1Mend"
+       style="overflow:visible;">
+      <path
+         id="path3982"
+         d="M 0.0,0.0 L 5.0,-5.0 L -12.5,0.0 L 5.0,5.0 L 0.0,0.0 z "
+         style="fill-rule:evenodd;stroke:#000000;stroke-width:1.0pt;"
+         transform="scale(0.4) rotate(180) translate(10,0)" />
+    </marker>
+  </defs>
+  <sodipodi:namedview
+     pagecolor="#ffffff"
+     bordercolor="#666666"
+     borderopacity="1"
+     objecttolerance="10"
+     gridtolerance="10"
+     guidetolerance="10"
+     inkscape:pageopacity="0"
+     inkscape:pageshadow="2"
+     inkscape:window-width="1134"
+     inkscape:window-height="789"
+     id="namedview220"
+     showgrid="false"
+     inkscape:zoom="0.60515873"
+     inkscape:cx="679.5"
+     inkscape:cy="504"
+     inkscape:window-x="786"
+     inkscape:window-y="24"
+     inkscape:window-maximized="0"
+     inkscape:current-layer="g4" />
+  <g
+     style="stroke-width:.025in; fill:none"
+     id="g4">
+    <!-- Line: box -->
+    <rect
+       x="450"
+       y="0"
+       width="17100"
+       height="8325"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffff00; "
+       id="rect6" />
+    <!-- Line: box -->
+    <rect
+       x="11025"
+       y="3600"
+       width="2700"
+       height="1350"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect8" />
+    <!-- Line: box -->
+    <rect
+       x="4275"
+       y="3600"
+       width="2700"
+       height="1350"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect10" />
+    <!-- Line: box -->
+    <rect
+       x="5400"
+       y="6300"
+       width="2700"
+       height="1350"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect12" />
+    <!-- Line: box -->
+    <rect
+       x="9900"
+       y="6300"
+       width="2700"
+       height="1350"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect14" />
+    <!-- Line: box -->
+    <rect
+       x="14400"
+       y="6300"
+       width="2700"
+       height="1350"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect16" />
+    <!-- Line: box -->
+    <rect
+       x="900"
+       y="6300"
+       width="2700"
+       height="1350"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect18" />
+    <!-- Line: box -->
+    <rect
+       x="7650"
+       y="900"
+       width="2700"
+       height="1350"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect20" />
+    <!-- Line -->
+    <polyline
+       points="3150,9225 3150,7746 "
+       style="stroke:#00d1d1;stroke-width:44.99790066;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline22" />
+    <!-- Arrowhead on XXXpoint 3150 9225 - 3150 7560-->
+    <!-- Circle -->
+    <circle
+       cx="8550"
+       cy="4275"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle26" />
+    <!-- Circle -->
+    <circle
+       cx="9000"
+       cy="4275"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle28" />
+    <!-- Circle -->
+    <circle
+       cx="9450"
+       cy="4275"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle30" />
+    <!-- Line -->
+    <polyline
+       points="6750,6300 8250,5010 "
+       style="stroke:#00d1d1;stroke-width:44.99790066;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline32" />
+    <!-- Arrowhead on XXXpoint 6750 6300 - 8391 4890-->
+    <!-- Line -->
+    <polyline
+       points="11250,6300 9747,5010 "
+       style="stroke:#00d1d1;stroke-width:44.99790066;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline36" />
+    <!-- Arrowhead on XXXpoint 11250 6300 - 9606 4890-->
+    <!-- Circle -->
+    <circle
+       cx="13950"
+       cy="6975"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle40" />
+    <!-- Circle -->
+    <circle
+       cx="13500"
+       cy="6975"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle42" />
+    <!-- Circle -->
+    <circle
+       cx="13050"
+       cy="6975"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle44" />
+    <!-- Circle -->
+    <circle
+       cx="9450"
+       cy="6975"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle46" />
+    <!-- Circle -->
+    <circle
+       cx="9000"
+       cy="6975"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle48" />
+    <!-- Circle -->
+    <circle
+       cx="8550"
+       cy="6975"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle50" />
+    <!-- Circle -->
+    <circle
+       cx="4950"
+       cy="6975"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle52" />
+    <!-- Circle -->
+    <circle
+       cx="4500"
+       cy="6975"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle54" />
+    <!-- Circle -->
+    <circle
+       cx="4050"
+       cy="6975"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle56" />
+    <!-- Circle -->
+    <circle
+       cx="1800"
+       cy="8775"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle58" />
+    <!-- Circle -->
+    <circle
+       cx="2250"
+       cy="8775"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle60" />
+    <!-- Circle -->
+    <circle
+       cx="2700"
+       cy="8775"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle62" />
+    <!-- Circle -->
+    <circle
+       cx="15300"
+       cy="8775"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle64" />
+    <!-- Circle -->
+    <circle
+       cx="15750"
+       cy="8775"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle66" />
+    <!-- Circle -->
+    <circle
+       cx="16200"
+       cy="8775"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle68" />
+    <!-- Circle -->
+    <circle
+       cx="10800"
+       cy="8775"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle70" />
+    <!-- Circle -->
+    <circle
+       cx="11250"
+       cy="8775"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle72" />
+    <!-- Circle -->
+    <circle
+       cx="11700"
+       cy="8775"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle74" />
+    <!-- Circle -->
+    <circle
+       cx="6300"
+       cy="8775"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle76" />
+    <!-- Circle -->
+    <circle
+       cx="6750"
+       cy="8775"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle78" />
+    <!-- Circle -->
+    <circle
+       cx="7200"
+       cy="8775"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle80" />
+    <!-- Line: box -->
+    <rect
+       x="0"
+       y="11475"
+       width="2700"
+       height="1800"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect82" />
+    <!-- Line: box -->
+    <rect
+       x="1800"
+       y="9225"
+       width="2700"
+       height="1800"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect84" />
+    <!-- Line: box -->
+    <rect
+       x="4500"
+       y="11475"
+       width="2700"
+       height="1800"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect86" />
+    <!-- Line: box -->
+    <rect
+       x="6300"
+       y="9270"
+       width="2700"
+       height="1800"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect88" />
+    <!-- Line: box -->
+    <rect
+       x="8955"
+       y="11475"
+       width="2700"
+       height="1800"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect90" />
+    <!-- Line: box -->
+    <rect
+       x="10755"
+       y="9270"
+       width="2700"
+       height="1800"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect92" />
+    <!-- Line: box -->
+    <rect
+       x="13455"
+       y="11475"
+       width="2700"
+       height="1800"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect94" />
+    <!-- Line: box -->
+    <rect
+       x="15255"
+       y="9270"
+       width="2700"
+       height="1800"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect96" />
+    <!-- Line -->
+    <polyline
+       points="11700,3600 10197,2310 "
+       style="stroke:#00d1d1;stroke-width:44.99790066;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline98" />
+    <!-- Arrowhead on XXXpoint 11700 3600 - 10056 2190-->
+    <!-- Line -->
+    <polyline
+       points="6300,3600 7800,2310 "
+       style="stroke:#00d1d1;stroke-width:44.99790066;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline102" />
+    <!-- Arrowhead on XXXpoint 6300 3600 - 7941 2190-->
+    <!-- Line -->
+    <polyline
+       points="3150,6300 4650,5010 "
+       style="stroke:#00d1d1;stroke-width:44.99790066;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline106" />
+    <!-- Arrowhead on XXXpoint 3150 6300 - 4791 4890-->
+    <!-- Line -->
+    <polyline
+       points="14850,6300 13347,5010 "
+       style="stroke:#00d1d1;stroke-width:44.99790066;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline110" />
+    <!-- Arrowhead on XXXpoint 14850 6300 - 13206 4890-->
+    <!-- Line -->
+    <polyline
+       points="1350,11475 1350,7746 "
+       style="stroke:#00d1d1;stroke-width:44.99790066;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline114" />
+    <!-- Arrowhead on XXXpoint 1350 11475 - 1350 7560-->
+    <!-- Line -->
+    <polyline
+       points="16650,9225 16650,7746 "
+       style="stroke:#00d1d1;stroke-width:44.99790066;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline118" />
+    <!-- Arrowhead on XXXpoint 16650 9225 - 16650 7560-->
+    <!-- Line -->
+    <polyline
+       points="14850,11475 14850,7746 "
+       style="stroke:#00d1d1;stroke-width:44.99790066;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline122" />
+    <!-- Arrowhead on XXXpoint 14850 11475 - 14850 7560-->
+    <!-- Line -->
+    <polyline
+       points="12150,9225 12150,7746 "
+       style="stroke:#00d1d1;stroke-width:44.99790066;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline126" />
+    <!-- Arrowhead on XXXpoint 12150 9225 - 12150 7560-->
+    <!-- Line -->
+    <polyline
+       points="10350,11475 10350,7746 "
+       style="stroke:#00d1d1;stroke-width:44.99790066;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline130" />
+    <!-- Arrowhead on XXXpoint 10350 11475 - 10350 7560-->
+    <!-- Line -->
+    <polyline
+       points="7650,9225 7650,7746 "
+       style="stroke:#00d1d1;stroke-width:44.99790066;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline134" />
+    <!-- Arrowhead on XXXpoint 7650 9225 - 7650 7560-->
+    <!-- Line -->
+    <polyline
+       points="5850,11475 5850,7746 "
+       style="stroke:#00d1d1;stroke-width:44.99790066;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline138" />
+    <!-- Arrowhead on XXXpoint 5850 11475 - 5850 7560-->
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="12375"
+       y="4500"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text142">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="12375"
+       y="4050"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text144">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="5625"
+       y="4050"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text146">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="5625"
+       y="4500"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text148">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="6750"
+       y="6750"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text150">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="6750"
+       y="7200"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text152">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="11250"
+       y="7200"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text154">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="11250"
+       y="6750"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text156">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="15750"
+       y="7200"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text158">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="15750"
+       y="6750"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text160">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="2250"
+       y="6750"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text162">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="2250"
+       y="7200"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text164">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1350"
+       y="13050"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="324"
+       text-anchor="middle"
+       id="text166">CPU 0</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1350"
+       y="11925"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text168">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1350"
+       y="12375"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text170">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="3150"
+       y="10800"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="324"
+       text-anchor="middle"
+       id="text172">CPU 15</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="3150"
+       y="9675"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text174">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="3150"
+       y="10125"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text176">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="5850"
+       y="11925"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text178">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="5850"
+       y="12375"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text180">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="5850"
+       y="13050"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="324"
+       text-anchor="middle"
+       id="text182">CPU 21823</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="7650"
+       y="10845"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="324"
+       text-anchor="middle"
+       id="text184">CPU 21839</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="7650"
+       y="10170"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text186">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="7650"
+       y="9720"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text188">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="10305"
+       y="11925"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text190">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="10305"
+       y="12375"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text192">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="10305"
+       y="13050"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="324"
+       text-anchor="middle"
+       id="text194">CPU 43679</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="12105"
+       y="10845"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="324"
+       text-anchor="middle"
+       id="text196">CPU 43695</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="12105"
+       y="10170"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text198">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="12105"
+       y="9720"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text200">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="14805"
+       y="11925"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text202">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="14805"
+       y="12375"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text204">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="14805"
+       y="13050"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="324"
+       text-anchor="middle"
+       id="text206">CPU 65519</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="16605"
+       y="10845"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="324"
+       text-anchor="middle"
+       id="text208">CPU 65535</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="16605"
+       y="10170"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text210">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="16605"
+       y="9720"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text212">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="675"
+       y="450"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="start"
+       id="text214">struct rcu_state</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="9000"
+       y="1350"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text216">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="9000"
+       y="1800"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text218">rcu_node</text>
+  </g>
+</svg>
diff --git a/Documentation/RCU/Design/Data-Structures/TreeLevel.svg b/Documentation/RCU/Design/Data-Structures/TreeLevel.svg
new file mode 100644
index 000000000000..7a7eb3bac95c
--- /dev/null
+++ b/Documentation/RCU/Design/Data-Structures/TreeLevel.svg
@@ -0,0 +1,828 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!-- Creator: fig2dev Version 3.2 Patchlevel 5e -->
+
+<!-- CreationDate: Wed Dec  9 17:41:29 2015 -->
+
+<!-- Magnification: 3.000 -->
+
+<svg
+   xmlns:dc="http://purl.org/dc/elements/1.1/"
+   xmlns:cc="http://creativecommons.org/ns#"
+   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+   xmlns:svg="http://www.w3.org/2000/svg"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
+   width="17.7in"
+   height="10.4in"
+   viewBox="-66 -66 21237 12507"
+   id="svg2"
+   version="1.1"
+   inkscape:version="0.48.4 r9939"
+   sodipodi:docname="TreeLevel.fig">
+  <metadata
+     id="metadata216">
+    <rdf:RDF>
+      <cc:Work
+         rdf:about="">
+        <dc:format>image/svg+xml</dc:format>
+        <dc:type
+           rdf:resource="http://purl.org/dc/dcmitype/StillImage" />
+        <dc:title></dc:title>
+      </cc:Work>
+    </rdf:RDF>
+  </metadata>
+  <defs
+     id="defs214">
+    <marker
+       inkscape:stockid="Arrow1Mend"
+       orient="auto"
+       refY="0.0"
+       refX="0.0"
+       id="Arrow1Mend"
+       style="overflow:visible;">
+      <path
+         id="path3974"
+         d="M 0.0,0.0 L 5.0,-5.0 L -12.5,0.0 L 5.0,5.0 L 0.0,0.0 z "
+         style="fill-rule:evenodd;stroke:#000000;stroke-width:1.0pt;"
+         transform="scale(0.4) rotate(180) translate(10,0)" />
+    </marker>
+  </defs>
+  <sodipodi:namedview
+     pagecolor="#ffffff"
+     bordercolor="#666666"
+     borderopacity="1"
+     objecttolerance="10"
+     gridtolerance="10"
+     guidetolerance="10"
+     inkscape:pageopacity="0"
+     inkscape:pageshadow="2"
+     inkscape:window-width="1023"
+     inkscape:window-height="1148"
+     id="namedview212"
+     showgrid="false"
+     inkscape:zoom="0.55869424"
+     inkscape:cx="796.50006"
+     inkscape:cy="467.99997"
+     inkscape:window-x="897"
+     inkscape:window-y="24"
+     inkscape:window-maximized="0"
+     inkscape:current-layer="g4" />
+  <g
+     style="stroke-width:.025in; fill:none"
+     id="g4">
+    <!-- Line: box -->
+    <rect
+       x="0"
+       y="0"
+       width="20655"
+       height="8325"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffff00; "
+       id="rect6" />
+    <!-- Line: box -->
+    <rect
+       x="14130"
+       y="3600"
+       width="2700"
+       height="1350"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect8" />
+    <!-- Line: box -->
+    <rect
+       x="7380"
+       y="3600"
+       width="2700"
+       height="1350"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect10" />
+    <!-- Line: box -->
+    <rect
+       x="8505"
+       y="6300"
+       width="2700"
+       height="1350"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect12" />
+    <!-- Line: box -->
+    <rect
+       x="13005"
+       y="6300"
+       width="2700"
+       height="1350"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect14" />
+    <!-- Line: box -->
+    <rect
+       x="17505"
+       y="6300"
+       width="2700"
+       height="1350"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect16" />
+    <!-- Line: box -->
+    <rect
+       x="4005"
+       y="6300"
+       width="2700"
+       height="1350"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect18" />
+    <!-- Line: box -->
+    <rect
+       x="10755"
+       y="900"
+       width="2700"
+       height="1350"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect20" />
+    <!-- Line -->
+    <polyline
+       points="6255,9225 6255,7746 "
+       style="stroke:#00d1d1;stroke-width:45.00382345;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline22" />
+    <!-- Arrowhead on XXXpoint 6255 9225 - 6255 7560-->
+    <!-- Circle -->
+    <circle
+       cx="11655"
+       cy="4275"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle26" />
+    <!-- Circle -->
+    <circle
+       cx="12105"
+       cy="4275"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle28" />
+    <!-- Circle -->
+    <circle
+       cx="12555"
+       cy="4275"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle30" />
+    <!-- Line -->
+    <polyline
+       points="9855,6300 11355,5010 "
+       style="stroke:#00d1d1;stroke-width:45.00382345;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline32" />
+    <!-- Arrowhead on XXXpoint 9855 6300 - 11496 4890-->
+    <!-- Line -->
+    <polyline
+       points="14355,6300 12852,5010 "
+       style="stroke:#00d1d1;stroke-width:45.00382345;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline36" />
+    <!-- Arrowhead on XXXpoint 14355 6300 - 12711 4890-->
+    <!-- Circle -->
+    <circle
+       cx="17055"
+       cy="6975"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle40" />
+    <!-- Circle -->
+    <circle
+       cx="16605"
+       cy="6975"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle42" />
+    <!-- Circle -->
+    <circle
+       cx="16155"
+       cy="6975"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle44" />
+    <!-- Circle -->
+    <circle
+       cx="12555"
+       cy="6975"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle46" />
+    <!-- Circle -->
+    <circle
+       cx="12105"
+       cy="6975"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle48" />
+    <!-- Circle -->
+    <circle
+       cx="11655"
+       cy="6975"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle50" />
+    <!-- Circle -->
+    <circle
+       cx="8055"
+       cy="6975"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle52" />
+    <!-- Circle -->
+    <circle
+       cx="7605"
+       cy="6975"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle54" />
+    <!-- Circle -->
+    <circle
+       cx="7155"
+       cy="6975"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle56" />
+    <!-- Circle -->
+    <circle
+       cx="4905"
+       cy="8775"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle58" />
+    <!-- Circle -->
+    <circle
+       cx="5355"
+       cy="8775"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle60" />
+    <!-- Circle -->
+    <circle
+       cx="5805"
+       cy="8775"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle62" />
+    <!-- Circle -->
+    <circle
+       cx="18405"
+       cy="8775"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle64" />
+    <!-- Circle -->
+    <circle
+       cx="18855"
+       cy="8775"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle66" />
+    <!-- Circle -->
+    <circle
+       cx="19305"
+       cy="8775"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle68" />
+    <!-- Circle -->
+    <circle
+       cx="13905"
+       cy="8775"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle70" />
+    <!-- Circle -->
+    <circle
+       cx="14355"
+       cy="8775"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle72" />
+    <!-- Circle -->
+    <circle
+       cx="14805"
+       cy="8775"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle74" />
+    <!-- Circle -->
+    <circle
+       cx="9405"
+       cy="8775"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle76" />
+    <!-- Circle -->
+    <circle
+       cx="9855"
+       cy="8775"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle78" />
+    <!-- Circle -->
+    <circle
+       cx="10305"
+       cy="8775"
+       r="114"
+       style="fill:#000000;stroke:#000000;stroke-width:21;"
+       id="circle80" />
+    <!-- Line: box -->
+    <rect
+       x="225"
+       y="1125"
+       width="3150"
+       height="1125"
+       rx="0"
+       style="stroke:#000000;stroke-width:21; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffffff; "
+       id="rect82" />
+    <!-- Line: box -->
+    <rect
+       x="225"
+       y="2250"
+       width="3150"
+       height="1125"
+       rx="0"
+       style="stroke:#000000;stroke-width:21; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffffff; "
+       id="rect84" />
+    <!-- Line: box -->
+    <rect
+       x="225"
+       y="3375"
+       width="3150"
+       height="1125"
+       rx="0"
+       style="stroke:#000000;stroke-width:21; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffffff; "
+       id="rect86" />
+    <!-- Line -->
+    <polyline
+       points="14805,3600 13302,2310 "
+       style="stroke:#00d1d1;stroke-width:45.00382345;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline88" />
+    <!-- Arrowhead on XXXpoint 14805 3600 - 13161 2190-->
+    <!-- Line -->
+    <polyline
+       points="9405,3600 10905,2310 "
+       style="stroke:#00d1d1;stroke-width:45.00382345;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline92" />
+    <!-- Arrowhead on XXXpoint 9405 3600 - 11046 2190-->
+    <!-- Line -->
+    <polyline
+       points="6255,6300 7755,5010 "
+       style="stroke:#00d1d1;stroke-width:45.00382345;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline96" />
+    <!-- Arrowhead on XXXpoint 6255 6300 - 7896 4890-->
+    <!-- Line -->
+    <polyline
+       points="17955,6300 16452,5010 "
+       style="stroke:#00d1d1;stroke-width:45.00382345;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline100" />
+    <!-- Arrowhead on XXXpoint 17955 6300 - 16311 4890-->
+    <!-- Line -->
+    <polyline
+       points="4455,11025 4455,7746 "
+       style="stroke:#00d1d1;stroke-width:45.00382345;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline104" />
+    <!-- Arrowhead on XXXpoint 4455 11025 - 4455 7560-->
+    <!-- Line -->
+    <polyline
+       points="19755,9225 19755,7746 "
+       style="stroke:#00d1d1;stroke-width:45.00382345;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline108" />
+    <!-- Arrowhead on XXXpoint 19755 9225 - 19755 7560-->
+    <!-- Line -->
+    <polyline
+       points="17955,11025 17955,7746 "
+       style="stroke:#00d1d1;stroke-width:45.00382345;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline112" />
+    <!-- Arrowhead on XXXpoint 17955 11025 - 17955 7560-->
+    <!-- Line -->
+    <polyline
+       points="15255,9225 15255,7746 "
+       style="stroke:#00d1d1;stroke-width:45.00382345;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline116" />
+    <!-- Arrowhead on XXXpoint 15255 9225 - 15255 7560-->
+    <!-- Line -->
+    <polyline
+       points="13455,11025 13455,7746 "
+       style="stroke:#00d1d1;stroke-width:45.00382345;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline120" />
+    <!-- Arrowhead on XXXpoint 13455 11025 - 13455 7560-->
+    <!-- Line -->
+    <polyline
+       points="10755,9225 10755,7746 "
+       style="stroke:#00d1d1;stroke-width:45.00382345;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline124" />
+    <!-- Arrowhead on XXXpoint 10755 9225 - 10755 7560-->
+    <!-- Line -->
+    <polyline
+       points="8955,11025 8955,7746 "
+       style="stroke:#00d1d1;stroke-width:45.00382345;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline128" />
+    <!-- Arrowhead on XXXpoint 8955 11025 - 8955 7560-->
+    <!-- Line: box -->
+    <rect
+       x="12105"
+       y="11025"
+       width="2700"
+       height="1350"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect132" />
+    <!-- Line: box -->
+    <rect
+       x="13905"
+       y="9225"
+       width="2700"
+       height="1350"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect134" />
+    <!-- Line: box -->
+    <rect
+       x="16605"
+       y="11025"
+       width="2700"
+       height="1350"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect136" />
+    <!-- Line: box -->
+    <rect
+       x="18405"
+       y="9225"
+       width="2700"
+       height="1350"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect138" />
+    <!-- Line: box -->
+    <rect
+       x="9405"
+       y="9225"
+       width="2700"
+       height="1350"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect140" />
+    <!-- Line: box -->
+    <rect
+       x="7605"
+       y="11025"
+       width="2700"
+       height="1350"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect142" />
+    <!-- Line: box -->
+    <rect
+       x="4905"
+       y="9225"
+       width="2700"
+       height="1350"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect144" />
+    <!-- Line: box -->
+    <rect
+       x="3105"
+       y="11025"
+       width="2700"
+       height="1350"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect146" />
+    <!-- Line -->
+    <polyline
+       points="3375,1575 10701,1575 "
+       style="stroke:#000000;stroke-width:45.00382345;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline148" />
+    <!-- Arrowhead on XXXpoint 3375 1575 - 10890 1575-->
+    <!-- Line -->
+    <polyline
+       points="3375,3825 4050,3825 4050,5400 2700,5400 2700,6975 3951,6975 "
+       style="stroke:#000000;stroke-width:45.00382345;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline152" />
+    <!-- Arrowhead on XXXpoint 2700 6975 - 4140 6975-->
+    <!-- Line -->
+    <polyline
+       points="3375,2700 5175,2700 5175,4275 7326,4275 "
+       style="stroke:#000000;stroke-width:45.00382345;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline156" />
+    <!-- Arrowhead on XXXpoint 5175 4275 - 7515 4275-->
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="15480"
+       y="4500"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text160">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="15480"
+       y="4050"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text162">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="8730"
+       y="4050"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text164">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="8730"
+       y="4500"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text166">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="9855"
+       y="6750"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text168">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="9855"
+       y="7200"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text170">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="14355"
+       y="7200"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text172">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="14355"
+       y="6750"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text174">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="18855"
+       y="7200"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text176">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="18855"
+       y="6750"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text178">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="5355"
+       y="6750"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text180">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="5355"
+       y="7200"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text182">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="450"
+       y="1800"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="324"
+       text-anchor="start"
+       id="text184">-&gt;level[0]</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="450"
+       y="2925"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="324"
+       text-anchor="start"
+       id="text186">-&gt;level[1]</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="450"
+       y="4050"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="324"
+       text-anchor="start"
+       id="text188">-&gt;level[2]</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="12105"
+       y="1350"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text190">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="12105"
+       y="1800"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="middle"
+       id="text192">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="6255"
+       y="10125"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="324"
+       text-anchor="middle"
+       id="text194">CPU 15</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="4455"
+       y="11925"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="324"
+       text-anchor="middle"
+       id="text196">CPU 0</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="19755"
+       y="10125"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="324"
+       text-anchor="middle"
+       id="text198">CPU 65535</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="17955"
+       y="11925"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="324"
+       text-anchor="middle"
+       id="text200">CPU 65519</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="15255"
+       y="10125"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="324"
+       text-anchor="middle"
+       id="text202">CPU 43695</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="13455"
+       y="11925"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="324"
+       text-anchor="middle"
+       id="text204">CPU 43679</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="10755"
+       y="10125"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="324"
+       text-anchor="middle"
+       id="text206">CPU 21839</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="8955"
+       y="11925"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="324"
+       text-anchor="middle"
+       id="text208">CPU 21823</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="225"
+       y="450"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="288"
+       text-anchor="start"
+       id="text210">struct rcu_state</text>
+  </g>
+</svg>
diff --git a/Documentation/RCU/Design/Data-Structures/TreeMapping.svg b/Documentation/RCU/Design/Data-Structures/TreeMapping.svg
new file mode 100644
index 000000000000..729cfa9e6cdb
--- /dev/null
+++ b/Documentation/RCU/Design/Data-Structures/TreeMapping.svg
@@ -0,0 +1,305 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!-- Creator: fig2dev Version 3.2 Patchlevel 5e -->
+
+<!-- CreationDate: Wed Dec  9 17:43:22 2015 -->
+
+<!-- Magnification: 1.000 -->
+
+<svg
+   xmlns:dc="http://purl.org/dc/elements/1.1/"
+   xmlns:cc="http://creativecommons.org/ns#"
+   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+   xmlns:svg="http://www.w3.org/2000/svg"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
+   width="3.1in"
+   height="0.9in"
+   viewBox="-12 -12 3699 1074"
+   id="svg2"
+   version="1.1"
+   inkscape:version="0.48.4 r9939"
+   sodipodi:docname="TreeMapping.fig">
+  <metadata
+     id="metadata66">
+    <rdf:RDF>
+      <cc:Work
+         rdf:about="">
+        <dc:format>image/svg+xml</dc:format>
+        <dc:type
+           rdf:resource="http://purl.org/dc/dcmitype/StillImage" />
+        <dc:title></dc:title>
+      </cc:Work>
+    </rdf:RDF>
+  </metadata>
+  <defs
+     id="defs64">
+    <marker
+       inkscape:stockid="Arrow2Lend"
+       orient="auto"
+       refY="0.0"
+       refX="0.0"
+       id="Arrow2Lend"
+       style="overflow:visible;">
+      <path
+         id="path3836"
+         style="fill-rule:evenodd;stroke-width:0.62500000;stroke-linejoin:round;"
+         d="M 8.7185878,4.0337352 L -2.2072895,0.016013256 L 8.7185884,-4.0017078 C 6.9730900,-1.6296469 6.9831476,1.6157441 8.7185878,4.0337352 z "
+         transform="scale(1.1) rotate(180) translate(1,0)" />
+    </marker>
+    <marker
+       inkscape:stockid="Arrow2Mend"
+       orient="auto"
+       refY="0.0"
+       refX="0.0"
+       id="Arrow2Mend"
+       style="overflow:visible;">
+      <path
+         id="path3842"
+         style="fill-rule:evenodd;stroke-width:0.62500000;stroke-linejoin:round;"
+         d="M 8.7185878,4.0337352 L -2.2072895,0.016013256 L 8.7185884,-4.0017078 C 6.9730900,-1.6296469 6.9831476,1.6157441 8.7185878,4.0337352 z "
+         transform="scale(0.6) rotate(180) translate(0,0)" />
+    </marker>
+    <marker
+       inkscape:stockid="Arrow1Mend"
+       orient="auto"
+       refY="0.0"
+       refX="0.0"
+       id="Arrow1Mend"
+       style="overflow:visible;">
+      <path
+         id="path3824"
+         d="M 0.0,0.0 L 5.0,-5.0 L -12.5,0.0 L 5.0,5.0 L 0.0,0.0 z "
+         style="fill-rule:evenodd;stroke:#000000;stroke-width:1.0pt;"
+         transform="scale(0.4) rotate(180) translate(10,0)" />
+    </marker>
+  </defs>
+  <sodipodi:namedview
+     pagecolor="#ffffff"
+     bordercolor="#666666"
+     borderopacity="1"
+     objecttolerance="10"
+     gridtolerance="10"
+     guidetolerance="10"
+     inkscape:pageopacity="0"
+     inkscape:pageshadow="2"
+     inkscape:window-width="991"
+     inkscape:window-height="606"
+     id="namedview62"
+     showgrid="false"
+     inkscape:zoom="3.0752688"
+     inkscape:cx="139.5"
+     inkscape:cy="40.5"
+     inkscape:window-x="891"
+     inkscape:window-y="177"
+     inkscape:window-maximized="0"
+     inkscape:current-layer="g4" />
+  <g
+     style="stroke-width:.025in; fill:none"
+     id="g4">
+    <!-- Line: box -->
+    <rect
+       x="0"
+       y="0"
+       width="3675"
+       height="1050"
+       rx="0"
+       style="stroke:#000000;stroke-width:7; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffff00; "
+       id="rect6" />
+    <!-- Line: box -->
+    <rect
+       x="75"
+       y="375"
+       width="375"
+       height="300"
+       rx="0"
+       style="stroke:#000000;stroke-width:7; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect8" />
+    <!-- Line: box -->
+    <rect
+       x="600"
+       y="375"
+       width="375"
+       height="300"
+       rx="0"
+       style="stroke:#000000;stroke-width:7; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect10" />
+    <!-- Line: box -->
+    <rect
+       x="1125"
+       y="375"
+       width="375"
+       height="300"
+       rx="0"
+       style="stroke:#000000;stroke-width:7; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect12" />
+    <!-- Line: box -->
+    <rect
+       x="1650"
+       y="375"
+       width="375"
+       height="300"
+       rx="0"
+       style="stroke:#000000;stroke-width:7; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect14" />
+    <!-- Line: box -->
+    <rect
+       x="2175"
+       y="375"
+       width="375"
+       height="300"
+       rx="0"
+       style="stroke:#000000;stroke-width:7; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect16" />
+    <!-- Line: box -->
+    <rect
+       x="3225"
+       y="375"
+       width="375"
+       height="300"
+       rx="0"
+       style="stroke:#000000;stroke-width:7; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect18" />
+    <!-- Line -->
+    <polyline
+       points="675,375 675,150 300,150 300,358 "
+       style="stroke:#000000;stroke-width:7.00088889;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow2Lend)"
+       id="polyline20" />
+    <!-- Arrowhead on XXXpoint 300 150 - 300 390-->
+    <!-- Line -->
+    <polyline
+       points="1200,675 1200,900 300,900 300,691 "
+       style="stroke:#000000;stroke-width:7.00088889;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow2Lend)"
+       id="polyline24" />
+    <!-- Arrowhead on XXXpoint 300 900 - 300 660-->
+    <!-- Line -->
+    <polyline
+       points="1725,375 1725,150 900,150 900,358 "
+       style="stroke:#000000;stroke-width:7.00088889;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow2Lend)"
+       id="polyline28" />
+    <!-- Arrowhead on XXXpoint 900 150 - 900 390-->
+    <!-- Line -->
+    <polyline
+       points="2250,375 2250,75 825,75 825,358 "
+       style="stroke:#000000;stroke-width:7.00088889;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow2Lend)"
+       id="polyline32" />
+    <!-- Arrowhead on XXXpoint 825 75 - 825 390-->
+    <!-- Line -->
+    <polyline
+       points="2775,675 2775,900 1425,900 1425,691 "
+       style="stroke:#000000;stroke-width:7.00088889;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow2Lend)"
+       id="polyline36" />
+    <!-- Arrowhead on XXXpoint 1425 900 - 1425 660-->
+    <!-- Line -->
+    <polyline
+       points="3300,675 3300,975 1350,975 1350,691 "
+       style="stroke:#000000;stroke-width:7.00088889;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow2Lend)"
+       id="polyline40" />
+    <!-- Arrowhead on XXXpoint 1350 975 - 1350 660-->
+    <!-- Line: box -->
+    <rect
+       x="2700"
+       y="375"
+       width="375"
+       height="300"
+       rx="0"
+       style="stroke:#000000;stroke-width:7; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect44" />
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="300"
+       y="525"
+       fill="#000000"
+       font-family="Times"
+       font-style="normal"
+       font-weight="normal"
+       font-size="96"
+       text-anchor="middle"
+       id="text46">0:7  </text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1350"
+       y="525"
+       fill="#000000"
+       font-family="Times"
+       font-style="normal"
+       font-weight="normal"
+       font-size="96"
+       text-anchor="middle"
+       id="text48">4:7  </text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1875"
+       y="525"
+       fill="#000000"
+       font-family="Times"
+       font-style="normal"
+       font-weight="normal"
+       font-size="96"
+       text-anchor="middle"
+       id="text50">0:1  </text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="2400"
+       y="525"
+       fill="#000000"
+       font-family="Times"
+       font-style="normal"
+       font-weight="normal"
+       font-size="96"
+       text-anchor="middle"
+       id="text52">2:3  </text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="2925"
+       y="525"
+       fill="#000000"
+       font-family="Times"
+       font-style="normal"
+       font-weight="normal"
+       font-size="96"
+       text-anchor="middle"
+       id="text54">4:5  </text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="3450"
+       y="525"
+       fill="#000000"
+       font-family="Times"
+       font-style="normal"
+       font-weight="normal"
+       font-size="96"
+       text-anchor="middle"
+       id="text56">6:7  </text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="825"
+       y="525"
+       fill="#000000"
+       font-family="Times"
+       font-style="normal"
+       font-weight="normal"
+       font-size="96"
+       text-anchor="middle"
+       id="text58">0:3  </text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="3600"
+       y="150"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="normal"
+       font-size="96"
+       text-anchor="end"
+       id="text60">struct rcu_state</text>
+  </g>
+</svg>
diff --git a/Documentation/RCU/Design/Data-Structures/TreeMappingLevel.svg b/Documentation/RCU/Design/Data-Structures/TreeMappingLevel.svg
new file mode 100644
index 000000000000..5b416a4b8453
--- /dev/null
+++ b/Documentation/RCU/Design/Data-Structures/TreeMappingLevel.svg
@@ -0,0 +1,380 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!-- Creator: fig2dev Version 3.2 Patchlevel 5e -->
+
+<!-- CreationDate: Wed Dec  9 17:45:19 2015 -->
+
+<!-- Magnification: 1.000 -->
+
+<svg
+   xmlns:dc="http://purl.org/dc/elements/1.1/"
+   xmlns:cc="http://creativecommons.org/ns#"
+   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+   xmlns:svg="http://www.w3.org/2000/svg"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
+   width="3.1in"
+   height="1.8in"
+   viewBox="-12 -12 3699 2124"
+   id="svg2"
+   version="1.1"
+   inkscape:version="0.48.4 r9939"
+   sodipodi:docname="TreeMappingLevel.svg">
+  <metadata
+     id="metadata98">
+    <rdf:RDF>
+      <cc:Work
+         rdf:about="">
+        <dc:format>image/svg+xml</dc:format>
+        <dc:type
+           rdf:resource="http://purl.org/dc/dcmitype/StillImage" />
+        <dc:title />
+      </cc:Work>
+    </rdf:RDF>
+  </metadata>
+  <defs
+     id="defs96">
+    <marker
+       inkscape:stockid="Arrow2Lend"
+       orient="auto"
+       refY="0.0"
+       refX="0.0"
+       id="Arrow2Lend"
+       style="overflow:visible;">
+      <path
+         id="path3868"
+         style="fill-rule:evenodd;stroke-width:0.62500000;stroke-linejoin:round;"
+         d="M 8.7185878,4.0337352 L -2.2072895,0.016013256 L 8.7185884,-4.0017078 C 6.9730900,-1.6296469 6.9831476,1.6157441 8.7185878,4.0337352 z "
+         transform="scale(1.1) rotate(180) translate(1,0)" />
+    </marker>
+  </defs>
+  <sodipodi:namedview
+     pagecolor="#ffffff"
+     bordercolor="#666666"
+     borderopacity="1"
+     objecttolerance="10"
+     gridtolerance="10"
+     guidetolerance="10"
+     inkscape:pageopacity="0"
+     inkscape:pageshadow="2"
+     inkscape:window-width="1598"
+     inkscape:window-height="1211"
+     id="namedview94"
+     showgrid="false"
+     inkscape:zoom="5.2508961"
+     inkscape:cx="139.5"
+     inkscape:cy="81"
+     inkscape:window-x="840"
+     inkscape:window-y="122"
+     inkscape:window-maximized="0"
+     inkscape:current-layer="g4" />
+  <g
+     style="stroke-width:.025in; fill:none"
+     id="g4">
+    <!-- Line: box -->
+    <rect
+       x="0"
+       y="0"
+       width="3675"
+       height="2100"
+       rx="0"
+       style="stroke:#000000;stroke-width:7; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffff00; "
+       id="rect6" />
+    <!-- Line: box -->
+    <rect
+       x="75"
+       y="1350"
+       width="750"
+       height="225"
+       rx="0"
+       style="stroke:#000000;stroke-width:7; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect8" />
+    <!-- Line: box -->
+    <rect
+       x="75"
+       y="1575"
+       width="750"
+       height="225"
+       rx="0"
+       style="stroke:#000000;stroke-width:7; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect10" />
+    <!-- Line: box -->
+    <rect
+       x="75"
+       y="1800"
+       width="750"
+       height="225"
+       rx="0"
+       style="stroke:#000000;stroke-width:7; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect12" />
+    <!-- Arc -->
+    <path
+       style="stroke:#000000;stroke-width:7;stroke-linecap:butt;"
+       d="M 1800,900 A 118 118  0  0  0  1800  1125 "
+       id="path14" />
+    <!-- Arc -->
+    <path
+       style="stroke:#000000;stroke-width:7;stroke-linecap:butt;"
+       d="M 750,900 A 75 75  0  0  0  750  1050 "
+       id="path16" />
+    <!-- Line -->
+    <polyline
+       points="750,900 750,691 "
+       style="stroke:#000000;stroke-width:7.00025806;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow2Lend)"
+       id="polyline18" />
+    <!-- Arrowhead on XXXpoint 750 900 - 750 660-->
+    <!-- Line: box -->
+    <rect
+       x="75"
+       y="375"
+       width="375"
+       height="300"
+       rx="0"
+       style="stroke:#000000;stroke-width:7; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect22" />
+    <!-- Line: box -->
+    <rect
+       x="600"
+       y="375"
+       width="375"
+       height="300"
+       rx="0"
+       style="stroke:#000000;stroke-width:7; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect24" />
+    <!-- Line: box -->
+    <rect
+       x="1650"
+       y="375"
+       width="375"
+       height="300"
+       rx="0"
+       style="stroke:#000000;stroke-width:7; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect26" />
+    <!-- Line: box -->
+    <rect
+       x="2175"
+       y="375"
+       width="375"
+       height="300"
+       rx="0"
+       style="stroke:#000000;stroke-width:7; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect28" />
+    <!-- Line: box -->
+    <rect
+       x="3225"
+       y="375"
+       width="375"
+       height="300"
+       rx="0"
+       style="stroke:#000000;stroke-width:7; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect30" />
+    <!-- Line -->
+    <polyline
+       points="675,375 675,150 300,150 300,358 "
+       style="stroke:#000000;stroke-width:7.00025806;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow2Lend)"
+       id="polyline32" />
+    <!-- Arrowhead on XXXpoint 300 150 - 300 390-->
+    <!-- Line -->
+    <polyline
+       points="1725,375 1725,150 900,150 900,358 "
+       style="stroke:#000000;stroke-width:7.00025806;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow2Lend)"
+       id="polyline36" />
+    <!-- Arrowhead on XXXpoint 900 150 - 900 390-->
+    <!-- Line -->
+    <polyline
+       points="2250,375 2250,75 825,75 825,358 "
+       style="stroke:#000000;stroke-width:7.00025806;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow2Lend)"
+       id="polyline40" />
+    <!-- Arrowhead on XXXpoint 825 75 - 825 390-->
+    <!-- Line -->
+    <polyline
+       points="2775,675 2775,975 1425,975 1425,691 "
+       style="stroke:#000000;stroke-width:7.00025806;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow2Lend)"
+       id="polyline44" />
+    <!-- Arrowhead on XXXpoint 1425 975 - 1425 660-->
+    <!-- Line: box -->
+    <rect
+       x="2700"
+       y="375"
+       width="375"
+       height="300"
+       rx="0"
+       style="stroke:#000000;stroke-width:7; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect48" />
+    <!-- Line: box -->
+    <rect
+       x="1125"
+       y="375"
+       width="375"
+       height="300"
+       rx="0"
+       style="stroke:#000000;stroke-width:7; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect50" />
+    <!-- Line -->
+    <polyline
+       points="3300,675 3300,1050 1350,1050 1350,691 "
+       style="stroke:#000000;stroke-width:7.00025806;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow2Lend)"
+       id="polyline52" />
+    <!-- Arrowhead on XXXpoint 1350 1050 - 1350 660-->
+    <!-- Line -->
+    <polyline
+       points="825,1425 975,1425 975,1200 225,1200 225,691 "
+       style="stroke:#000000;stroke-width:7.00025806;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow2Lend)"
+       id="polyline56" />
+    <!-- Arrowhead on XXXpoint 225 1200 - 225 660-->
+    <!-- Line -->
+    <polyline
+       points="1200,675 1200,975 300,975 300,691 "
+       style="stroke:#000000;stroke-width:7.00025806;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow2Lend)"
+       id="polyline60" />
+    <!-- Arrowhead on XXXpoint 300 975 - 300 660-->
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="150"
+       y="1500"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="108"
+       text-anchor="start"
+       id="text64">-&gt;level[0]</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="150"
+       y="1725"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="108"
+       text-anchor="start"
+       id="text66">-&gt;level[1]</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="150"
+       y="1950"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="108"
+       text-anchor="start"
+       id="text68">-&gt;level[2]</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="300"
+       y="525"
+       fill="#000000"
+       font-family="Times"
+       font-style="normal"
+       font-weight="normal"
+       font-size="96"
+       text-anchor="middle"
+       id="text70">0:7  </text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1350"
+       y="525"
+       fill="#000000"
+       font-family="Times"
+       font-style="normal"
+       font-weight="normal"
+       font-size="96"
+       text-anchor="middle"
+       id="text72">4:7  </text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1875"
+       y="525"
+       fill="#000000"
+       font-family="Times"
+       font-style="normal"
+       font-weight="normal"
+       font-size="96"
+       text-anchor="middle"
+       id="text74">0:1  </text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="2400"
+       y="525"
+       fill="#000000"
+       font-family="Times"
+       font-style="normal"
+       font-weight="normal"
+       font-size="96"
+       text-anchor="middle"
+       id="text76">2:3  </text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="2925"
+       y="525"
+       fill="#000000"
+       font-family="Times"
+       font-style="normal"
+       font-weight="normal"
+       font-size="96"
+       text-anchor="middle"
+       id="text78">4:5  </text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="3450"
+       y="525"
+       fill="#000000"
+       font-family="Times"
+       font-style="normal"
+       font-weight="normal"
+       font-size="96"
+       text-anchor="middle"
+       id="text80">6:7  </text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="825"
+       y="525"
+       fill="#000000"
+       font-family="Times"
+       font-style="normal"
+       font-weight="normal"
+       font-size="96"
+       text-anchor="middle"
+       id="text82">0:3  </text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="3600"
+       y="150"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="normal"
+       font-size="96"
+       text-anchor="end"
+       id="text84">struct rcu_state</text>
+    <!-- Line -->
+    <polyline
+       points="825,1875 1800,1875 1800,1125 "
+       style="stroke:#000000;stroke-width:7.00025806;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:none"
+       id="polyline86" />
+    <!-- Line -->
+    <polyline
+       points="1800,900 1800,691 "
+       style="stroke:#000000;stroke-width:7.00025806;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow2Lend)"
+       id="polyline88" />
+    <!-- Arrowhead on XXXpoint 1800 900 - 1800 660-->
+    <!-- Line -->
+    <polyline
+       points="825,1650 1200,1650 1200,1125 750,1125 750,1050 "
+       style="stroke:#000000;stroke-width:7; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="polyline92" />
+  </g>
+</svg>
diff --git a/Documentation/RCU/Design/Data-Structures/blkd_task.svg b/Documentation/RCU/Design/Data-Structures/blkd_task.svg
new file mode 100644
index 000000000000..00e810bb8419
--- /dev/null
+++ b/Documentation/RCU/Design/Data-Structures/blkd_task.svg
@@ -0,0 +1,843 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!-- Creator: fig2dev Version 3.2 Patchlevel 5e -->
+
+<!-- CreationDate: Wed Dec  9 17:35:03 2015 -->
+
+<!-- Magnification: 2.000 -->
+
+<svg
+   xmlns:dc="http://purl.org/dc/elements/1.1/"
+   xmlns:cc="http://creativecommons.org/ns#"
+   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+   xmlns:svg="http://www.w3.org/2000/svg"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
+   width="10.1in"
+   height="8.6in"
+   viewBox="-44 -44 12088 10288"
+   id="svg2"
+   version="1.1"
+   inkscape:version="0.48.4 r9939"
+   sodipodi:docname="blkd_task.fig">
+  <metadata
+     id="metadata212">
+    <rdf:RDF>
+      <cc:Work
+         rdf:about="">
+        <dc:format>image/svg+xml</dc:format>
+        <dc:type
+           rdf:resource="http://purl.org/dc/dcmitype/StillImage" />
+        <dc:title></dc:title>
+      </cc:Work>
+    </rdf:RDF>
+  </metadata>
+  <defs
+     id="defs210">
+    <marker
+       inkscape:stockid="Arrow1Mend"
+       orient="auto"
+       refY="0.0"
+       refX="0.0"
+       id="Arrow1Mend"
+       style="overflow:visible;">
+      <path
+         id="path3970"
+         d="M 0.0,0.0 L 5.0,-5.0 L -12.5,0.0 L 5.0,5.0 L 0.0,0.0 z "
+         style="fill-rule:evenodd;stroke:#000000;stroke-width:1.0pt;"
+         transform="scale(0.4) rotate(180) translate(10,0)" />
+    </marker>
+  </defs>
+  <sodipodi:namedview
+     pagecolor="#ffffff"
+     bordercolor="#666666"
+     borderopacity="1"
+     objecttolerance="10"
+     gridtolerance="10"
+     guidetolerance="10"
+     inkscape:pageopacity="0"
+     inkscape:pageshadow="2"
+     inkscape:window-width="1087"
+     inkscape:window-height="1144"
+     id="namedview208"
+     showgrid="false"
+     inkscape:zoom="1.0495049"
+     inkscape:cx="454.50003"
+     inkscape:cy="387.00003"
+     inkscape:window-x="833"
+     inkscape:window-y="28"
+     inkscape:window-maximized="0"
+     inkscape:current-layer="g4" />
+  <g
+     style="stroke-width:.025in; fill:none"
+     id="g4">
+    <!-- Line: box -->
+    <rect
+       x="450"
+       y="0"
+       width="6300"
+       height="7350"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffffff; "
+       id="rect6" />
+    <!-- Line: box -->
+    <rect
+       x="4950"
+       y="4950"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect8" />
+    <!-- Line: box -->
+    <rect
+       x="750"
+       y="600"
+       width="5700"
+       height="3750"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffff00; "
+       id="rect10" />
+    <!-- Line -->
+    <polyline
+       points="5250,8100 5688,5912 "
+       style="stroke:#00ff00;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="polyline12" />
+    <!-- Arrowhead on XXXpoint 5250 8100 - 5710 5790-->
+    <polyline
+       points="5714 6068 5704 5822 5598 6044 "
+       style="stroke:#00ff00;stroke-width:14;stroke-miterlimit:8; "
+       id="polyline14" />
+    <!-- Line -->
+    <polyline
+       points="4050,9300 4486,7262 "
+       style="stroke:#00ff00;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="polyline16" />
+    <!-- Arrowhead on XXXpoint 4050 9300 - 4512 7140-->
+    <polyline
+       points="4514 7418 4506 7172 4396 7394 "
+       style="stroke:#00ff00;stroke-width:14;stroke-miterlimit:8; "
+       id="polyline18" />
+    <!-- Line -->
+    <polyline
+       points="1040,9300 1476,7262 "
+       style="stroke:#00ff00;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="polyline20" />
+    <!-- Arrowhead on XXXpoint 1040 9300 - 1502 7140-->
+    <polyline
+       points="1504 7418 1496 7172 1386 7394 "
+       style="stroke:#00ff00;stroke-width:14;stroke-miterlimit:8; "
+       id="polyline22" />
+    <!-- Line -->
+    <polyline
+       points="2240,8100 2676,6062 "
+       style="stroke:#00ff00;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="polyline24" />
+    <!-- Arrowhead on XXXpoint 2240 8100 - 2702 5940-->
+    <polyline
+       points="2704 6218 2696 5972 2586 6194 "
+       style="stroke:#00ff00;stroke-width:14;stroke-miterlimit:8; "
+       id="polyline26" />
+    <!-- Line: box -->
+    <rect
+       x="0"
+       y="450"
+       width="6300"
+       height="7350"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffffff; "
+       id="rect28" />
+    <!-- Line: box -->
+    <rect
+       x="300"
+       y="1050"
+       width="5700"
+       height="3750"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffff00; "
+       id="rect30" />
+    <!-- Line -->
+    <polyline
+       points="1350,3450 2350,2590 "
+       style="stroke:#00d1d1;stroke-width:30.00057884;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline32" />
+    <!-- Arrowhead on XXXpoint 1350 3450 - 2444 2510-->
+    <!-- Line -->
+    <polyline
+       points="4950,3450 3948,2590 "
+       style="stroke:#00d1d1;stroke-width:30.00057884;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline36" />
+    <!-- Arrowhead on XXXpoint 4950 3450 - 3854 2510-->
+    <!-- Line -->
+    <polyline
+       points="4050,6600 4050,4414 "
+       style="stroke:#00d1d1;stroke-width:30.00057884;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline40" />
+    <!-- Arrowhead on XXXpoint 4050 6600 - 4050 4290-->
+    <!-- Line -->
+    <polyline
+       points="1050,6600 1050,4414 "
+       style="stroke:#00d1d1;stroke-width:30.00057884;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline44" />
+    <!-- Arrowhead on XXXpoint 1050 6600 - 1050 4290-->
+    <!-- Line -->
+    <polyline
+       points="2250,5400 2250,4414 "
+       style="stroke:#00d1d1;stroke-width:30.00057884;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline48" />
+    <!-- Arrowhead on XXXpoint 2250 5400 - 2250 4290-->
+    <!-- Line -->
+    <polyline
+       points="2250,8100 2250,6364 "
+       style="stroke:#00ff00;stroke-width:30.00057884;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline52" />
+    <!-- Arrowhead on XXXpoint 2250 8100 - 2250 6240-->
+    <!-- Line -->
+    <polyline
+       points="1050,9300 1050,7564 "
+       style="stroke:#00ff00;stroke-width:30.00057884;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline56" />
+    <!-- Arrowhead on XXXpoint 1050 9300 - 1050 7440-->
+    <!-- Line -->
+    <polyline
+       points="4050,9300 4050,7564 "
+       style="stroke:#00ff00;stroke-width:30.00057884;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline60" />
+    <!-- Arrowhead on XXXpoint 4050 9300 - 4050 7440-->
+    <!-- Line -->
+    <polyline
+       points="5250,8100 5250,6364 "
+       style="stroke:#00ff00;stroke-width:30.00057884;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline64" />
+    <!-- Arrowhead on XXXpoint 5250 8100 - 5250 6240-->
+    <!-- Circle -->
+    <circle
+       cx="2850"
+       cy="3900"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle68" />
+    <!-- Circle -->
+    <circle
+       cx="3150"
+       cy="3900"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle70" />
+    <!-- Circle -->
+    <circle
+       cx="3450"
+       cy="3900"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle72" />
+    <!-- Circle -->
+    <circle
+       cx="1350"
+       cy="5100"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle74" />
+    <!-- Circle -->
+    <circle
+       cx="1650"
+       cy="5100"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle76" />
+    <!-- Circle -->
+    <circle
+       cx="1950"
+       cy="5100"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle78" />
+    <!-- Circle -->
+    <circle
+       cx="4350"
+       cy="5100"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle80" />
+    <!-- Circle -->
+    <circle
+       cx="4650"
+       cy="5100"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle82" />
+    <!-- Circle -->
+    <circle
+       cx="4950"
+       cy="5100"
+       r="76"
+       style="fill:#000000;stroke:#000000;stroke-width:14;"
+       id="circle84" />
+    <!-- Line: box -->
+    <rect
+       x="750"
+       y="3450"
+       width="1800"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect86" />
+    <!-- Line: box -->
+    <rect
+       x="300"
+       y="6600"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect88" />
+    <!-- Line: box -->
+    <rect
+       x="4500"
+       y="5400"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect90" />
+    <!-- Line: box -->
+    <rect
+       x="3300"
+       y="6600"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect92" />
+    <!-- Line: box -->
+    <rect
+       x="2250"
+       y="1650"
+       width="1800"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect94" />
+    <!-- Line: box -->
+    <rect
+       x="0"
+       y="9300"
+       width="2100"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#00ff00; "
+       id="rect96" />
+    <!-- Line: box -->
+    <rect
+       x="1350"
+       y="8100"
+       width="2100"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#00ff00; "
+       id="rect98" />
+    <!-- Line: box -->
+    <rect
+       x="3000"
+       y="9300"
+       width="2100"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#00ff00; "
+       id="rect100" />
+    <!-- Line: box -->
+    <rect
+       x="4350"
+       y="8100"
+       width="2100"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#00ff00; "
+       id="rect102" />
+    <!-- Line: box -->
+    <rect
+       x="1500"
+       y="5400"
+       width="1500"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect104" />
+    <!-- Line -->
+    <polygon
+       points="5550,3450 7350,2850 7350,5100 5550,4350 5550,3450 "
+       style="stroke:#000000;stroke-width:14; stroke-linejoin:miter; stroke-linecap:butt; stroke-dasharray:120 120;fill:#ffbfbf; "
+       id="polygon106" />
+    <!-- Line -->
+    <polyline
+       points="9300,3150 10734,3150 "
+       style="stroke:#000000;stroke-width:30.00057884;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline108" />
+    <!-- Arrowhead on XXXpoint 9300 3150 - 10860 3150-->
+    <!-- Line: box -->
+    <rect
+       x="10800"
+       y="2850"
+       width="1200"
+       height="750"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect112" />
+    <!-- Line -->
+    <polyline
+       points="11400,3600 11400,4284 "
+       style="stroke:#000000;stroke-width:30.00057884;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline114" />
+    <!-- Arrowhead on XXXpoint 11400 3600 - 11400 4410-->
+    <!-- Line: box -->
+    <rect
+       x="10800"
+       y="4350"
+       width="1200"
+       height="750"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect118" />
+    <!-- Line -->
+    <polyline
+       points="11400,5100 11400,5784 "
+       style="stroke:#000000;stroke-width:30.00057884;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline120" />
+    <!-- Arrowhead on XXXpoint 11400 5100 - 11400 5910-->
+    <!-- Line: box -->
+    <rect
+       x="10800"
+       y="5850"
+       width="1200"
+       height="750"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect124" />
+    <!-- Line -->
+    <polyline
+       points="9300,3900 9900,3900 9900,4650 10734,4650 "
+       style="stroke:#000000;stroke-width:30.00057884;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline126" />
+    <!-- Arrowhead on XXXpoint 9900 4650 - 10860 4650-->
+    <!-- Line -->
+    <polyline
+       points="9300,4650 9600,4650 9600,6150 10734,6150 "
+       style="stroke:#000000;stroke-width:30.00057884;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline130" />
+    <!-- Arrowhead on XXXpoint 9600 6150 - 10860 6150-->
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="6450"
+       y="300"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="192"
+       text-anchor="end"
+       id="text134">rcu_bh</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="3150"
+       y="1950"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text136">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="3150"
+       y="2250"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text138">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1650"
+       y="3750"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text140">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1650"
+       y="4050"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text142">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="2250"
+       y="5700"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text144">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="2250"
+       y="6000"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text146">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1050"
+       y="6900"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text148">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1050"
+       y="7200"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text150">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="5250"
+       y="5700"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text152">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="5250"
+       y="6000"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text154">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="4050"
+       y="6900"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text156">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="4050"
+       y="7200"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text158">rcu_data</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="450"
+       y="1350"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="start"
+       id="text160">struct rcu_state</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1050"
+       y="9600"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text162">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="1050"
+       y="9900"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text164">rcu_dynticks</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="4050"
+       y="9600"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text166">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="4050"
+       y="9900"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text168">rcu_dynticks</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="2400"
+       y="8400"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text170">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="2400"
+       y="8700"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text172">rcu_dynticks</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="5400"
+       y="8400"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text174">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="5400"
+       y="8700"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text176">rcu_dynticks</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="6000"
+       y="750"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="192"
+       text-anchor="end"
+       id="text178">rcu_sched</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="11400"
+       y="3300"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="216"
+       text-anchor="middle"
+       id="text180">T3</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="11400"
+       y="4800"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="216"
+       text-anchor="middle"
+       id="text182">T2</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="11400"
+       y="6300"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="216"
+       text-anchor="middle"
+       id="text184">T1</text>
+    <!-- Line -->
+    <polyline
+       points="5250,5400 5250,4414 "
+       style="stroke:#00d1d1;stroke-width:30.00057884;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline186" />
+    <!-- Arrowhead on XXXpoint 5250 5400 - 5250 4290-->
+    <!-- Line: box -->
+    <rect
+       x="3750"
+       y="3450"
+       width="1800"
+       height="900"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect190" />
+    <!-- Line: box -->
+    <rect
+       x="7350"
+       y="2850"
+       width="1950"
+       height="750"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect192" />
+    <!-- Line: box -->
+    <rect
+       x="7350"
+       y="3600"
+       width="1950"
+       height="750"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect194" />
+    <!-- Line: box -->
+    <rect
+       x="7350"
+       y="4350"
+       width="1950"
+       height="750"
+       rx="0"
+       style="stroke:#000000;stroke-width:30; stroke-linejoin:miter; stroke-linecap:butt; fill:#ffbfbf; "
+       id="rect196" />
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="4650"
+       y="4050"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text198">rcu_node</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="4650"
+       y="3750"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="middle"
+       id="text200">struct</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="7500"
+       y="3300"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="start"
+       id="text202">blkd_tasks</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="7500"
+       y="4050"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="start"
+       id="text204">gp_tasks</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="7500"
+       y="4800"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="192"
+       text-anchor="start"
+       id="text206">exp_tasks</text>
+  </g>
+</svg>
diff --git a/Documentation/RCU/Design/Data-Structures/nxtlist.svg b/Documentation/RCU/Design/Data-Structures/nxtlist.svg
new file mode 100644
index 000000000000..abc4cc73a097
--- /dev/null
+++ b/Documentation/RCU/Design/Data-Structures/nxtlist.svg
@@ -0,0 +1,396 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!-- Creator: fig2dev Version 3.2 Patchlevel 5e -->
+
+<!-- CreationDate: Wed Dec  9 17:39:46 2015 -->
+
+<!-- Magnification: 3.000 -->
+
+<svg
+   xmlns:dc="http://purl.org/dc/elements/1.1/"
+   xmlns:cc="http://creativecommons.org/ns#"
+   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+   xmlns:svg="http://www.w3.org/2000/svg"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
+   width="10.4in"
+   height="10.4in"
+   viewBox="-66 -66 12507 12507"
+   id="svg2"
+   version="1.1"
+   inkscape:version="0.48.4 r9939"
+   sodipodi:docname="nxtlist.fig">
+  <metadata
+     id="metadata94">
+    <rdf:RDF>
+      <cc:Work
+         rdf:about="">
+        <dc:format>image/svg+xml</dc:format>
+        <dc:type
+           rdf:resource="http://purl.org/dc/dcmitype/StillImage" />
+        <dc:title></dc:title>
+      </cc:Work>
+    </rdf:RDF>
+  </metadata>
+  <defs
+     id="defs92">
+    <marker
+       inkscape:stockid="Arrow1Mend"
+       orient="auto"
+       refY="0.0"
+       refX="0.0"
+       id="Arrow1Mend"
+       style="overflow:visible;">
+      <path
+         id="path3852"
+         d="M 0.0,0.0 L 5.0,-5.0 L -12.5,0.0 L 5.0,5.0 L 0.0,0.0 z "
+         style="fill-rule:evenodd;stroke:#000000;stroke-width:1.0pt;"
+         transform="scale(0.4) rotate(180) translate(10,0)" />
+    </marker>
+  </defs>
+  <sodipodi:namedview
+     pagecolor="#ffffff"
+     bordercolor="#666666"
+     borderopacity="1"
+     objecttolerance="10"
+     gridtolerance="10"
+     guidetolerance="10"
+     inkscape:pageopacity="0"
+     inkscape:pageshadow="2"
+     inkscape:window-width="925"
+     inkscape:window-height="928"
+     id="namedview90"
+     showgrid="false"
+     inkscape:zoom="0.80021373"
+     inkscape:cx="467.99997"
+     inkscape:cy="467.99997"
+     inkscape:window-x="948"
+     inkscape:window-y="73"
+     inkscape:window-maximized="0"
+     inkscape:current-layer="g4" />
+  <g
+     style="stroke-width:.025in; fill:none"
+     id="g4">
+    <!-- Line: box -->
+    <rect
+       x="0"
+       y="0"
+       width="7875"
+       height="1125"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect6" />
+    <!-- Line: box -->
+    <rect
+       x="0"
+       y="1125"
+       width="7875"
+       height="1125"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect8" />
+    <!-- Line: box -->
+    <rect
+       x="0"
+       y="2250"
+       width="7875"
+       height="1125"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect10" />
+    <!-- Line: box -->
+    <rect
+       x="0"
+       y="3375"
+       width="7875"
+       height="1125"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect12" />
+    <!-- Line: box -->
+    <rect
+       x="0"
+       y="4500"
+       width="7875"
+       height="1125"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; fill:#87cfff; "
+       id="rect14" />
+    <!-- Line: box -->
+    <rect
+       x="10575"
+       y="0"
+       width="1800"
+       height="1125"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect16" />
+    <!-- Line: box -->
+    <rect
+       x="10575"
+       y="1125"
+       width="1800"
+       height="1125"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect18" />
+    <!-- Line -->
+    <polyline
+       points="11475,2250 11475,3276 "
+       style="stroke:#000000;stroke-width:45.00382345;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline20" />
+    <!-- Arrowhead on XXXpoint 11475 2250 - 11475 3465-->
+    <!-- Line: box -->
+    <rect
+       x="10575"
+       y="6750"
+       width="1800"
+       height="1125"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect24" />
+    <!-- Line: box -->
+    <rect
+       x="10575"
+       y="7875"
+       width="1800"
+       height="1125"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect26" />
+    <!-- Line: box -->
+    <rect
+       x="10575"
+       y="10125"
+       width="1800"
+       height="1125"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect28" />
+    <!-- Line: box -->
+    <rect
+       x="10575"
+       y="11250"
+       width="1800"
+       height="1125"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect30" />
+    <!-- Line: box -->
+    <rect
+       x="10575"
+       y="3375"
+       width="1800"
+       height="1125"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect32" />
+    <!-- Line -->
+    <polyline
+       points="11475,5625 11475,6651 "
+       style="stroke:#000000;stroke-width:45.00382345;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline34" />
+    <!-- Arrowhead on XXXpoint 11475 5625 - 11475 6840-->
+    <!-- Line -->
+    <polyline
+       points="7875,225 10476,225 "
+       style="stroke:#000000;stroke-width:45.00382345;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline38" />
+    <!-- Arrowhead on XXXpoint 7875 225 - 10665 225-->
+    <!-- Line -->
+    <polyline
+       points="7875,1350 9675,1350 9675,675 7971,675 "
+       style="stroke:#000000;stroke-width:45.00382345;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline42" />
+    <!-- Arrowhead on XXXpoint 9675 675 - 7785 675-->
+    <!-- Line -->
+    <polyline
+       points="7875,2475 9675,2475 9675,4725 10476,4725 "
+       style="stroke:#000000;stroke-width:45.00382345;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline46" />
+    <!-- Arrowhead on XXXpoint 9675 4725 - 10665 4725-->
+    <!-- Line -->
+    <polyline
+       points="7875,3600 9225,3600 9225,5175 10476,5175 "
+       style="stroke:#000000;stroke-width:45.00382345;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline50" />
+    <!-- Arrowhead on XXXpoint 9225 5175 - 10665 5175-->
+    <!-- Line -->
+    <polyline
+       points="7875,4725 8775,4725 8775,11475 10476,11475 "
+       style="stroke:#000000;stroke-width:45.00382345;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline54" />
+    <!-- Arrowhead on XXXpoint 8775 11475 - 10665 11475-->
+    <!-- Line: box -->
+    <rect
+       x="10575"
+       y="4500"
+       width="1800"
+       height="1125"
+       rx="0"
+       style="stroke:#000000;stroke-width:45; stroke-linejoin:miter; stroke-linecap:butt; "
+       id="rect58" />
+    <!-- Line -->
+    <polyline
+       points="11475,9000 11475,10026 "
+       style="stroke:#000000;stroke-width:45.00382345;stroke-linejoin:miter;stroke-linecap:butt;stroke-miterlimit:4;stroke-dasharray:none;marker-end:url(#Arrow1Mend)"
+       id="polyline60" />
+    <!-- Arrowhead on XXXpoint 11475 9000 - 11475 10215-->
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="225"
+       y="675"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="324"
+       text-anchor="start"
+       id="text64">nxtlist</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="225"
+       y="1800"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="324"
+       text-anchor="start"
+       id="text66">nxttail[RCU_DONE_TAIL]</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="225"
+       y="2925"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="324"
+       text-anchor="start"
+       id="text68">nxttail[RCU_WAIT_TAIL]</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="225"
+       y="4050"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="324"
+       text-anchor="start"
+       id="text70">nxttail[RCU_NEXT_READY_TAIL]</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="225"
+       y="5175"
+       fill="#000000"
+       font-family="Courier"
+       font-style="normal"
+       font-weight="bold"
+       font-size="324"
+       text-anchor="start"
+       id="text72">nxttail[RCU_NEXT_TAIL]</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="11475"
+       y="675"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="324"
+       text-anchor="middle"
+       id="text74">CB 1</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="11475"
+       y="1800"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="324"
+       text-anchor="middle"
+       id="text76">next</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="11475"
+       y="7425"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="324"
+       text-anchor="middle"
+       id="text78">CB 3</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="11475"
+       y="8550"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="324"
+       text-anchor="middle"
+       id="text80">next</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="11475"
+       y="10800"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="324"
+       text-anchor="middle"
+       id="text82">CB 4</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="11475"
+       y="11925"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="324"
+       text-anchor="middle"
+       id="text84">next</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="11475"
+       y="4050"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="324"
+       text-anchor="middle"
+       id="text86">CB 2</text>
+    <!-- Text -->
+    <text
+       xml:space="preserve"
+       x="11475"
+       y="5175"
+       fill="#000000"
+       font-family="Helvetica"
+       font-style="normal"
+       font-weight="normal"
+       font-size="324"
+       text-anchor="middle"
+       id="text88">next</text>
+  </g>
+</svg>