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| author | Michal Hocko <mhocko@suse.cz> | 2012-01-11 00:07:21 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-01-11 01:30:42 +0100 |
| commit | ef009b25f4f8a77d2b32067d424d5ac757dcdc5b (patch) | |
| tree | 4972dac6ca66279277da1b328d9f6d32bcf08dd0 /mm/hugetlb.c | |
| parent | hugetlb: detect race upon page allocation failure during COW (diff) | |
| download | linux-ef009b25f4f8a77d2b32067d424d5ac757dcdc5b.tar.xz linux-ef009b25f4f8a77d2b32067d424d5ac757dcdc5b.zip | |
hugetlb: clarify hugetlb_instantiation_mutex usage
Let's make it clear that we cannot race with other fault handlers due to
hugetlb (global) mutex. Also make it clear that we want to keep pte_same
checks anayway to have a transition from the global mutex easier.
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/hugetlb.c')
| -rw-r--r-- | mm/hugetlb.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 2c551b28ba69..49e693b7fd0c 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2349,6 +2349,9 @@ static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma, /* * Hugetlb_cow() should be called with page lock of the original hugepage held. + * Called with hugetlb_instantiation_mutex held and pte_page locked so we + * cannot race with other handlers or page migration. + * Keep the pte_same checks anyway to make transition from the mutex easier. */ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, pte_t *ptep, pte_t pte, |