The patch titled
Subject: mm, thp: fix collapsing of hugepages on madvise
has been added to the -mm tree. Its filename is
mm-thp-fix-collapsing-of-hugepages-on-madvise.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-thp-fix-collapsing-of-hugepages-on-madvise.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-thp-fix-collapsing-of-hugepages-on-madvise.patch
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------------------------------------------------------
From: David Rientjes <rientjes@xxxxxxxxxx>
Subject: 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@xxxxxxxxxx>
Reported-by: Suleiman Souhlal <suleiman@xxxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/khugepaged.h | 17 ++++++++++-------
mm/huge_memory.c | 11 ++++++-----
mm/mmap.c | 8 ++++----
3 files changed, 20 insertions(+), 16 deletions(-)
diff -puN include/linux/khugepaged.h~mm-thp-fix-collapsing-of-hugepages-on-madvise include/linux/khugepaged.h
--- a/include/linux/khugepaged.h~mm-thp-fix-collapsing-of-hugepages-on-madvise
+++ a/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(struc
__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
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;
}
diff -puN mm/huge_memory.c~mm-thp-fix-collapsing-of-hugepages-on-madvise mm/huge_memory.c
--- a/mm/huge_memory.c~mm-thp-fix-collapsing-of-hugepages-on-madvise
+++ a/mm/huge_memory.c
@@ -803,7 +803,7 @@ int do_huge_pmd_anonymous_page(struct mm
return VM_FAULT_FALLBACK;
if (unlikely(anon_vma_prepare(vma)))
return VM_FAULT_OOM;
- if (unlikely(khugepaged_enter(vma)))
+ if (unlikely(khugepaged_enter(vma, vma->vm_flags)))
return VM_FAULT_OOM;
if (!(flags & FAULT_FLAG_WRITE) &&
transparent_hugepage_use_zero_page()) {
@@ -1970,7 +1970,7 @@ int hugepage_madvise(struct vm_area_stru
* register it here without waiting a page fault that
* may not happen any time soon.
*/
- if (unlikely(khugepaged_enter_vma_merge(vma)))
+ if (unlikely(khugepaged_enter_vma_merge(vma, *vm_flags)))
return -ENOMEM;
break;
case MADV_NOHUGEPAGE:
@@ -2071,7 +2071,8 @@ int __khugepaged_enter(struct mm_struct
return 0;
}
-int khugepaged_enter_vma_merge(struct vm_area_struct *vma)
+int khugepaged_enter_vma_merge(struct vm_area_struct *vma,
+ unsigned long vm_flags)
{
unsigned long hstart, hend;
if (!vma->anon_vma)
@@ -2083,11 +2084,11 @@ int khugepaged_enter_vma_merge(struct vm
if (vma->vm_ops)
/* khugepaged not yet working on file or special mappings */
return 0;
- VM_BUG_ON_VMA(vma->vm_flags & VM_NO_THP, vma);
+ VM_BUG_ON_VMA(vm_flags & VM_NO_THP, vma);
hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK;
hend = vma->vm_end & HPAGE_PMD_MASK;
if (hstart < hend)
- return khugepaged_enter(vma);
+ return khugepaged_enter(vma, vm_flags);
return 0;
}
diff -puN mm/mmap.c~mm-thp-fix-collapsing-of-hugepages-on-madvise mm/mmap.c
--- a/mm/mmap.c~mm-thp-fix-collapsing-of-hugepages-on-madvise
+++ a/mm/mmap.c
@@ -1080,7 +1080,7 @@ struct vm_area_struct *vma_merge(struct
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
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_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_stru
}
}
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;
}
_
Patches currently in -mm which might be from rientjes@xxxxxxxxxx are
origin.patch
mm-compaction-avoid-premature-range-skip-in-isolate_migratepages_range.patch
mm-free-compound-page-with-correct-order.patch
mm-thp-fix-collapsing-of-hugepages-on-madvise.patch
mm-memcontrol-lockless-page-counters.patch
mm-hugetlb_cgroup-convert-to-lockless-page-counters.patch
kernel-res_counter-remove-the-unused-api.patch
mm-memcontrol-convert-reclaim-iterator-to-simple-css-refcounting.patch
mm-memcontrol-take-a-css-reference-for-each-charged-page.patch
mm-memcontrol-remove-obsolete-kmemcg-pinning-tricks.patch
mm-memcontrol-continue-cache-reclaim-from-offlined-groups.patch
mm-memcontrol-remove-synchroneous-stock-draining-code.patch
mm-verify-compound-order-when-freeing-a-page.patch
mm-compaction-pass-classzone_idx-and-alloc_flags-to-watermark-checking.patch
mm-compaction-simplify-deferred-compaction.patch
mm-compaction-defer-only-on-compact_complete.patch
mm-compaction-always-update-cached-scanner-positions.patch
mm-compaction-more-focused-lru-and-pcplists-draining.patch
freezer-check-oom-kill-while-being-frozen.patch
freezer-remove-obsolete-comments-in-__thaw_task.patch
oom-pm-oom-killed-task-cannot-escape-pm-suspend.patch
mm-utilc-add-kstrimdup.patch
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