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authorDavid Rientjes <rientjes@google.com>2014-10-29 14:50:31 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-10-29 16:33:14 -0700
commit6d50e60cd2edb5a57154db5a6f64eef5aa59b751 (patch)
tree025056e23d57062c5e045d54613edc2e2fc4ca86 /mm/mmap.c
parent47f29df7db78ee4fcdb104cf36918d987ddd0278 (diff)
mm, thp: fix collapsing of hugepages on madvise
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> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/mmap.c')
-rw-r--r--mm/mmap.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index 7f855206e7fb..87e82b38453c 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1080,7 +1080,7 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm,
end, prev->vm_pgoff, NULL);
if (err)
return NULL;
- khugepaged_enter_vma_merge(prev);
+ khugepaged_enter_vma_merge(prev, vm_flags);
return prev;
}
@@ -1099,7 +1099,7 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm,
next->vm_pgoff - pglen, NULL);
if (err)
return NULL;
- khugepaged_enter_vma_merge(area);
+ khugepaged_enter_vma_merge(area, vm_flags);
return area;
}
@@ -2208,7 +2208,7 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
}
}
vma_unlock_anon_vma(vma);
- khugepaged_enter_vma_merge(vma);
+ khugepaged_enter_vma_merge(vma, vma->vm_flags);
validate_mm(vma->vm_mm);
return error;
}
@@ -2277,7 +2277,7 @@ int expand_downwards(struct vm_area_struct *vma,
}
}
vma_unlock_anon_vma(vma);
- khugepaged_enter_vma_merge(vma);
+ khugepaged_enter_vma_merge(vma, vma->vm_flags);
validate_mm(vma->vm_mm);
return error;
}