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-rw-r--r--Documentation/vm/transhuge.txt10
1 files changed, 8 insertions, 2 deletions
diff --git a/Documentation/vm/transhuge.txt b/Documentation/vm/transhuge.txt
index c4171e4519c2..cd28d5ee5273 100644
--- a/Documentation/vm/transhuge.txt
+++ b/Documentation/vm/transhuge.txt
@@ -110,6 +110,7 @@ MADV_HUGEPAGE region.
echo always >/sys/kernel/mm/transparent_hugepage/defrag
echo defer >/sys/kernel/mm/transparent_hugepage/defrag
+echo defer+madvise >/sys/kernel/mm/transparent_hugepage/defrag
echo madvise >/sys/kernel/mm/transparent_hugepage/defrag
echo never >/sys/kernel/mm/transparent_hugepage/defrag
@@ -120,10 +121,15 @@ that benefit heavily from THP use and are willing to delay the VM start
to utilise them.
"defer" means that an application will wake kswapd in the background
-to reclaim pages and wake kcompact to compact memory so that THP is
+to reclaim pages and wake kcompactd to compact memory so that THP is
available in the near future. It's the responsibility of khugepaged
to then install the THP pages later.
+"defer+madvise" will enter direct reclaim and compaction like "always", but
+only for regions that have used madvise(MADV_HUGEPAGE); all other regions
+will wake kswapd in the background to reclaim pages and wake kcompactd to
+compact memory so that THP is available in the near future.
+
"madvise" will enter direct reclaim like "always" but only for regions
that are have used madvise(MADV_HUGEPAGE). This is the default behaviour.
@@ -296,7 +302,7 @@ thp_split_page is incremented every time a huge page is split into base
reason is that a huge page is old and is being reclaimed.
This action implies splitting all PMD the page mapped with.
-thp_split_page_failed is is incremented if kernel fails to split huge
+thp_split_page_failed is incremented if kernel fails to split huge
page. This can happen if the page was pinned by somebody.
thp_deferred_split_page is incremented when a huge page is put onto split