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authorNishanth Aravamudan <nacc@us.ibm.com>2008-04-15 14:34:43 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-15 19:35:41 -0700
commit423bec43079a2942a3004034df7aad76469758d8 (patch)
treedf77cdba718cbee8a61946689390c92eb3c2ab83
parent91446b064c748fc2a238fd68b677c9671e536bfd (diff)
downloadlinux-423bec43079a2942a3004034df7aad76469758d8.tar.gz
linux-423bec43079a2942a3004034df7aad76469758d8.tar.xz
Documentation: correct overcommit caveat in hugetlbpage.txt
As shown by Gurudas Pai recently, we can put hugepages into the surplus state (by echo 0 > /proc/sys/vm/nr_hugepages), even when /proc/sys/vm/nr_overcommit_hugepages is 0. This is actually correct, to allow the original goal (shrink the static pool to 0) to succeed (we are converting hugepages to surplus because they are in use). However, the documentation does not accurately reflect this case. Update it. Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com> Acked-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--Documentation/vm/hugetlbpage.txt7
1 files changed, 3 insertions, 4 deletions
diff --git a/Documentation/vm/hugetlbpage.txt b/Documentation/vm/hugetlbpage.txt
index f962d01..3102b81 100644
--- a/Documentation/vm/hugetlbpage.txt
+++ b/Documentation/vm/hugetlbpage.txt
@@ -88,10 +88,9 @@ hugepages from the buddy allocator, if the normal pool is exhausted. As
these surplus hugepages go out of use, they are freed back to the buddy
allocator.
-Caveat: Shrinking the pool via nr_hugepages while a surplus is in effect
-will allow the number of surplus huge pages to exceed the overcommit
-value, as the pool hugepages (which must have been in use for a surplus
-hugepages to be allocated) will become surplus hugepages. As long as
+Caveat: Shrinking the pool via nr_hugepages such that it becomes less
+than the number of hugepages in use will convert the balance to surplus
+huge pages even if it would exceed the overcommit value. As long as
this condition holds, however, no more surplus huge pages will be
allowed on the system until one of the two sysctls are increased
sufficiently, or the surplus huge pages go out of use and are freed.