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| author | Mel Gorman <mel@csn.ul.ie> | 2009-05-05 16:37:17 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-05-08 14:54:36 -0700 |
| commit | 0d8f4f2015d4f9ea3057e2d521084944306e91df (patch) | |
| tree | 71a3e46e916bdb121aecb70abe7c5c711b7f7bd1 | |
| parent | 2ee201a9d57df7a12e228c6a9b06a15014231b72 (diff) | |
| download | lwn-0d8f4f2015d4f9ea3057e2d521084944306e91df.tar.gz lwn-0d8f4f2015d4f9ea3057e2d521084944306e91df.zip | |
Ignore madvise(MADV_WILLNEED) for hugetlbfs-backed regions
commit a425a638c858fd10370b573bde81df3ba500e271 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | mm/madvise.c | 8 |
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; |