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| author | David Rientjes <rientjes@google.com> | 2014-10-29 14:50:31 -0700 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2014-12-14 16:23:52 +0000 |
| commit | 37e867c16ad3f6ac7e117d87f55e3863cb2854a2 (patch) | |
| tree | 7f1905ecf991639906e0459205afabfeb1a5043d /include/linux | |
| parent | e0fb1fad0739d6c56264ebeaf7fc7ae61b085632 (diff) | |
| download | kernel_samsung_smdk4412-37e867c16ad3f6ac7e117d87f55e3863cb2854a2.zip kernel_samsung_smdk4412-37e867c16ad3f6ac7e117d87f55e3863cb2854a2.tar.gz kernel_samsung_smdk4412-37e867c16ad3f6ac7e117d87f55e3863cb2854a2.tar.bz2 | |
mm, thp: fix collapsing of hugepages on madvise
commit 6d50e60cd2edb5a57154db5a6f64eef5aa59b751 upstream.
If an anonymous mapping is not allowed to fault thp memory and then
madvise(MADV_HUGEPAGE) is used after fault, khugepaged will never
collapse this memory into thp memory.
This occurs because the madvise(2) handler for thp, hugepage_madvise(),
clears VM_NOHUGEPAGE on the stack and it isn't stored in vma->vm_flags
until the final action of madvise_behavior(). This causes the
khugepaged_enter_vma_merge() to be a no-op in hugepage_madvise() when
the vma had previously had VM_NOHUGEPAGE set.
Fix this by passing the correct vma flags to the khugepaged mm slot
handler. There's no chance khugepaged can run on this vma until after
madvise_behavior() returns since we hold mm->mmap_sem.
It would be possible to clear VM_NOHUGEPAGE directly from vma->vm_flags
in hugepage_advise(), but I didn't want to introduce special case
behavior into madvise_behavior(). I think it's best to just let it
always set vma->vm_flags itself.
Signed-off-by: David Rientjes <rientjes@google.com>
Reported-by: Suleiman Souhlal <suleiman@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2: adjust context, indentation]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/khugepaged.h | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/include/linux/khugepaged.h b/include/linux/khugepaged.h index 6b394f0..eeb3079 100644 --- a/include/linux/khugepaged.h +++ b/include/linux/khugepaged.h @@ -6,7 +6,8 @@ #ifdef CONFIG_TRANSPARENT_HUGEPAGE extern int __khugepaged_enter(struct mm_struct *mm); extern void __khugepaged_exit(struct mm_struct *mm); -extern int khugepaged_enter_vma_merge(struct vm_area_struct *vma); +extern int khugepaged_enter_vma_merge(struct vm_area_struct *vma, + unsigned long vm_flags); #define khugepaged_enabled() \ (transparent_hugepage_flags & \ @@ -35,13 +36,13 @@ static inline void khugepaged_exit(struct mm_struct *mm) __khugepaged_exit(mm); } -static inline int khugepaged_enter(struct vm_area_struct *vma) +static inline int khugepaged_enter(struct vm_area_struct *vma, + unsigned long vm_flags) { if (!test_bit(MMF_VM_HUGEPAGE, &vma->vm_mm->flags)) if ((khugepaged_always() || - (khugepaged_req_madv() && - vma->vm_flags & VM_HUGEPAGE)) && - !(vma->vm_flags & VM_NOHUGEPAGE)) + (khugepaged_req_madv() && (vm_flags & VM_HUGEPAGE))) && + !(vm_flags & VM_NOHUGEPAGE)) if (__khugepaged_enter(vma->vm_mm)) return -ENOMEM; return 0; @@ -54,11 +55,13 @@ static inline int khugepaged_fork(struct mm_struct *mm, struct mm_struct *oldmm) static inline void khugepaged_exit(struct mm_struct *mm) { } -static inline int khugepaged_enter(struct vm_area_struct *vma) +static inline int khugepaged_enter(struct vm_area_struct *vma, + unsigned long vm_flags) { return 0; } -static inline int khugepaged_enter_vma_merge(struct vm_area_struct *vma) +static inline int khugepaged_enter_vma_merge(struct vm_area_struct *vma, + unsigned long vm_flags) { return 0; } |