The patch titled
Subject: mm: thp: register mm for khugepaged when merging vma for shmem
has been added to the -mm tree. Its filename is
mm-thp-register-mm-for-khugepaged-when-merging-vma-for-shmem-v3.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-thp-register-mm-for-khugepaged-when-merging-vma-for-shmem-v3.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-thp-register-mm-for-khugepaged-when-merging-vma-for-shmem-v3.patch
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------------------------------------------------------
From: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx>
Subject: mm: thp: register mm for khugepaged when merging vma for shmem
When merging anonymous page vma, if the size of the vma can fit in at
least one hugepage, the mm will be registered for khugepaged for
collapsing THP in the future.
But it skips shmem vmas. Do so for shmem also, but not for file-private
mappings when merging a vma in order to increase the odds of collapsing a
hugepage via khugepaged.
hugepage_vma_check() sounds like a good fit to do the check. And move the
definition of it before khugepaged_enter_vma_merge() to avoid a build
error.
Link: http://lkml.kernel.org/r/1529697791-6950-1-git-send-email-yang.shi@xxxxxxxxxxxxxxxxx
Signed-off-by: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/khugepaged.c | 53 ++++++++++++++++++++++------------------------
1 file changed, 26 insertions(+), 27 deletions(-)
diff -puN mm/khugepaged.c~mm-thp-register-mm-for-khugepaged-when-merging-vma-for-shmem-v3 mm/khugepaged.c
--- a/mm/khugepaged.c~mm-thp-register-mm-for-khugepaged-when-merging-vma-for-shmem-v3
+++ a/mm/khugepaged.c
@@ -397,6 +397,25 @@ static inline int khugepaged_test_exit(s
return atomic_read(&mm->mm_users) == 0;
}
+static bool hugepage_vma_check(struct vm_area_struct *vma)
+{
+ if ((!(vma->vm_flags & VM_HUGEPAGE) && !khugepaged_always()) ||
+ (vma->vm_flags & VM_NOHUGEPAGE) ||
+ test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags))
+ return false;
+ if (shmem_file(vma->vm_file)) {
+ if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE))
+ return false;
+ return IS_ALIGNED((vma->vm_start >> PAGE_SHIFT) - vma->vm_pgoff,
+ HPAGE_PMD_NR);
+ }
+ if (!vma->anon_vma || vma->vm_ops)
+ return false;
+ if (is_vma_temporary_stack(vma))
+ return false;
+ return !(vma->vm_flags & VM_NO_KHUGEPAGED);
+}
+
int __khugepaged_enter(struct mm_struct *mm)
{
struct mm_slot *mm_slot;
@@ -434,15 +453,14 @@ int khugepaged_enter_vma_merge(struct vm
unsigned long vm_flags)
{
unsigned long hstart, hend;
- if (!vma->anon_vma)
- /*
- * Not yet faulted in so we will register later in the
- * page fault if needed.
- */
- return 0;
- if (vma->vm_ops || (vm_flags & VM_NO_KHUGEPAGED))
- /* khugepaged not yet working on file or special mappings */
+
+ /*
+ * khugepaged does not yet work on non-shmem files or special
+ * mappings. And file-private shmem THP is not supported.
+ */
+ if (!hugepage_vma_check(vma))
return 0;
+
hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK;
hend = vma->vm_end & HPAGE_PMD_MASK;
if (hstart < hend)
@@ -819,25 +837,6 @@ khugepaged_alloc_page(struct page **hpag
}
#endif
-static bool hugepage_vma_check(struct vm_area_struct *vma)
-{
- if ((!(vma->vm_flags & VM_HUGEPAGE) && !khugepaged_always()) ||
- (vma->vm_flags & VM_NOHUGEPAGE) ||
- test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags))
- return false;
- if (shmem_file(vma->vm_file)) {
- if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE))
- return false;
- return IS_ALIGNED((vma->vm_start >> PAGE_SHIFT) - vma->vm_pgoff,
- HPAGE_PMD_NR);
- }
- if (!vma->anon_vma || vma->vm_ops)
- return false;
- if (is_vma_temporary_stack(vma))
- return false;
- return !(vma->vm_flags & VM_NO_KHUGEPAGED);
-}
-
/*
* If mmap_sem temporarily dropped, revalidate vma
* before taking mmap_sem.
_
Patches currently in -mm which might be from yang.shi@xxxxxxxxxxxxxxxxx are
doc-add-description-to-dirtytime_expire_seconds.patch
thp-use-mm_file_counter-to-determine-update-which-rss-counter.patch
mm-thp-register-mm-for-khugepaged-when-merging-vma-for-shmem-v3.patch
mm-thp-inc-counter-for-collapsed-shmem-thp.patch
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