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authorMel Gorman <mel@csn.ul.ie>2009-05-05 11:37:17 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2009-05-05 17:37:58 -0400
commita425a638c858fd10370b573bde81df3ba500e271 (patch)
tree4cb1f1172467ed07999b0aff952dc12b1e61add6 /mm
parent99ee12973e5fd1123ed1779fb4d11ac7d381d430 (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')
-rw-r--r--mm/madvise.c8
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,
112 if (!file) 112 if (!file)
113 return -EBADF; 113 return -EBADF;
114 114
115 /*
116 * Page cache readahead assumes page cache pages are order-0 which
117 * is not the case for hugetlbfs. Do not give a bad return value
118 * but ignore the advice.
119 */
120 if (vma->vm_flags & VM_HUGETLB)
121 return 0;
122
115 if (file->f_mapping->a_ops->get_xip_mem) { 123 if (file->f_mapping->a_ops->get_xip_mem) {
116 /* no bad return value, but ignore advice */ 124 /* no bad return value, but ignore advice */
117 return 0; 125 return 0;