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 /include | |
| parent | mm: exclude HugeTLB pages from THP page_mapped() logic (diff) | |
| download | linux-dev-aa88b68c3b1dce8bc3fd54c8a7372a777ff265cd.tar.xz linux-dev-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 'include')
| -rw-r--r-- | include/linux/huge_mm.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index 7008623e24b1..d7b9e5346fba 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -152,6 +152,7 @@ static inline bool is_huge_zero_pmd(pmd_t pmd) } struct page *get_huge_zero_page(void); +void put_huge_zero_page(void); #else /* CONFIG_TRANSPARENT_HUGEPAGE */ #define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; }) @@ -208,6 +209,10 @@ static inline bool is_huge_zero_page(struct page *page) return false; } +static inline void put_huge_zero_page(void) +{ + BUILD_BUG(); +} static inline struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, pmd_t *pmd, int flags) |