path: root/mm
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authorMel Gorman <mel@csn.ul.ie>2009-05-05 16:37:17 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2009-05-05 14:37:58 -0700
commita425a638c858fd10370b573bde81df3ba500e271 (patch)
tree4cb1f1172467ed07999b0aff952dc12b1e61add6 /mm
parentMerge branch 'timers/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip (diff)
Ignore madvise(MADV_WILLNEED) for hugetlbfs-backed regions
madvise(MADV_WILLNEED) forces page cache readahead on a range of memory backed by a file. The assumption is made that the page required is order-0 and "normal" page cache. On hugetlbfs, this assumption is not true and order-0 pages are allocated and inserted into the hugetlbfs page cache. This leaks hugetlbfs page reservations and can cause BUGs to trigger related to corrupted page tables. This patch causes MADV_WILLNEED to be ignored for hugetlbfs-backed regions. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
1 files changed, 8 insertions, 0 deletions
diff --git a/mm/madvise.c b/mm/madvise.c
index b9ce574827c8..36d6ea2b6340 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -112,6 +112,14 @@ static long madvise_willneed(struct vm_area_struct * vma,
if (!file)
return -EBADF;
+ /*
+ * Page cache readahead assumes page cache pages are order-0 which
+ * is not the case for hugetlbfs. Do not give a bad return value
+ * but ignore the advice.
+ */
+ if (vma->vm_flags & VM_HUGETLB)
+ return 0;
if (file->f_mapping->a_ops->get_xip_mem) {
/* no bad return value, but ignore advice */
return 0;