diff options
| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2016-04-28 16:18:27 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-04-28 19:34:04 -0700 |
| commit | aa88b68c3b1dce8bc3fd54c8a7372a777ff265cd (patch) | |
| tree | 98ad92a044b6a2f39a8fa4c1c24df001108bd1a8 /mm/swap.c | |
| parent | 66ee95d16a7f1b7b4f1dd74a2d81c6e19dc29a14 (diff) | |
| download | lwn-aa88b68c3b1dce8bc3fd54c8a7372a777ff265cd.tar.gz lwn-aa88b68c3b1dce8bc3fd54c8a7372a777ff265cd.zip | |
thp: keep huge zero page pinned until tlb flush
Andrea has found[1] a race condition on MMU-gather based TLB flush vs
split_huge_page() or shrinker which frees huge zero under us (patch 1/2
and 2/2 respectively).
With new THP refcounting, we don't need patch 1/2: mmu_gather keeps the
page pinned until flush is complete and the pin prevents the page from
being split under us.
We still need patch 2/2. This is simplified version of Andrea's patch.
We don't need fancy encoding.
[1] http://lkml.kernel.org/r/1447938052-22165-1-git-send-email-aarcange@redhat.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/swap.c')
| -rw-r--r-- | mm/swap.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/mm/swap.c b/mm/swap.c index a0bc206b4ac6..03aacbcb013f 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -728,6 +728,11 @@ void release_pages(struct page **pages, int nr, bool cold) zone = NULL; } + if (is_huge_zero_page(page)) { + put_huge_zero_page(); + continue; + } + page = compound_head(page); if (!put_page_testzero(page)) continue; |