hugetlbfs: extend the definition of hugepages parameter to support node allocation

We can specify the number of hugepages to allocate at boot.  But the
hugepages is balanced in all nodes at present.  In some scenarios, we
only need hugepages in one node.  For example: DPDK needs hugepages
which are in the same node as NIC.

If DPDK needs four hugepages of 1G size in node1 and system has 16 numa
nodes we must reserve 64 hugepages on the kernel cmdline.  But only four
hugepages are used.  The others should be free after boot.  If the
system memory is low(for example: 64G), it will be an impossible task.

So extend the hugepages parameter to support specifying hugepages on a
specific node.  For example add following parameter:

  hugepagesz=1G hugepages=0:1,1:3

It will allocate 1 hugepage in node0 and 3 hugepages in node1.

Link: https://lkml.kernel.org/r/20211005054729.86457-1-yaozhenguo1@gmail.com
Signed-off-by: Zhenguo Yao <yaozhenguo1@gmail.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Zhenguo Yao <yaozhenguo1@gmail.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 16 insertions, 4 deletions

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index e7f7904edf20..02eeda2a11ad 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1601,9 +1601,11 @@
 			the number of pages of hugepagesz to be allocated.
 			If this is the first HugeTLB parameter on the command
 			line, it specifies the number of pages to allocate for
-			the default huge page size.  See also
-			Documentation/admin-guide/mm/hugetlbpage.rst.
-			Format: <integer>
+			the default huge page size. If using node format, the
+			number of pages to allocate per-node can be specified.
+			See also Documentation/admin-guide/mm/hugetlbpage.rst.
+			Format: <integer> or (node format)
+				<node>:<integer>[,<node>:<integer>]
 
 	hugepagesz=
 			[HW] The size of the HugeTLB pages.  This is used in
diff --git a/Documentation/admin-guide/mm/hugetlbpage.rst b/Documentation/admin-guide/mm/hugetlbpage.rst
index bb90de3885d1..0166f9de3428 100644
--- a/Documentation/admin-guide/mm/hugetlbpage.rst
+++ b/Documentation/admin-guide/mm/hugetlbpage.rst
@@ -128,7 +128,9 @@ hugepages
 	implicitly specifies the number of huge pages of default size to
 	allocate.  If the number of huge pages of default size is implicitly
 	specified, it can not be overwritten by a hugepagesz,hugepages
-	parameter pair for the default size.
+	parameter pair for the default size.  This parameter also has a
+	node format.  The node format specifies the number of huge pages
+	to allocate on specific nodes.
 
 	For example, on an architecture with 2M default huge page size::
 
@@ -138,6 +140,14 @@ hugepages
 	indicating that the hugepages=512 parameter is ignored.  If a hugepages
 	parameter is preceded by an invalid hugepagesz parameter, it will
 	be ignored.
+
+	Node format example::
+
+		hugepagesz=2M hugepages=0:1,1:2
+
+	It will allocate 1 2M hugepage on node0 and 2 2M hugepages on node1.
+	If the node number is invalid,  the parameter will be ignored.
+
 default_hugepagesz
 	Specify the default huge page size.  This parameter can
 	only be specified once on the command line.  default_hugepagesz can