The patch titled
Subject: mm: pvmw: check possible huge PMD map by transhuge_vma_suitable()
has been added to the -mm mm-unstable branch. Its filename is
mm-pvmw-check-possible-huge-pmd-map-by-transhuge_vma_suitable.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-pvmw-check-possible-huge-pmd-map-by-transhuge_vma_suitable.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Yang Shi <shy828301@xxxxxxxxx>
Subject: mm: pvmw: check possible huge PMD map by transhuge_vma_suitable()
Date: Fri, 13 May 2022 12:17:05 -0700
IIUC PVMW checks if the vma is possibly huge PMD mapped by
transparent_hugepage_active() and "pvmw->nr_pages >= HPAGE_PMD_NR".
Actually pvmw->nr_pages is returned by compound_nr() or
folio_nr_pages(), so the page should be THP as long as "pvmw->nr_pages
>= HPAGE_PMD_NR". And it is guaranteed THP is allocated for valid VMA
in the first place. But it may be not PMD mapped if the VMA is file
VMA and it is not properly aligned. The transhuge_vma_suitable()
is used to do such check, so replace transparent_hugepage_active() to
it, which is too heavy and overkilling.
Link: https://lkml.kernel.org/r/20220513191705.457775-1-shy828301@xxxxxxxxx
Signed-off-by: Yang Shi <shy828301@xxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/huge_mm.h | 8 ++++++--
mm/page_vma_mapped.c | 2 +-
2 files changed, 7 insertions(+), 3 deletions(-)
--- a/include/linux/huge_mm.h~mm-pvmw-check-possible-huge-pmd-map-by-transhuge_vma_suitable
+++ a/include/linux/huge_mm.h
@@ -117,8 +117,10 @@ extern struct kobj_attribute shmem_enabl
extern unsigned long transparent_hugepage_flags;
static inline bool transhuge_vma_suitable(struct vm_area_struct *vma,
- unsigned long haddr)
+ unsigned long addr)
{
+ unsigned long haddr;
+
/* Don't have to check pgoff for anonymous vma */
if (!vma_is_anonymous(vma)) {
if (!IS_ALIGNED((vma->vm_start >> PAGE_SHIFT) - vma->vm_pgoff,
@@ -126,6 +128,8 @@ static inline bool transhuge_vma_suitabl
return false;
}
+ haddr = addr & HPAGE_PMD_MASK;
+
if (haddr < vma->vm_start || haddr + HPAGE_PMD_SIZE > vma->vm_end)
return false;
return true;
@@ -342,7 +346,7 @@ static inline bool transparent_hugepage_
}
static inline bool transhuge_vma_suitable(struct vm_area_struct *vma,
- unsigned long haddr)
+ unsigned long addr)
{
return false;
}
--- a/mm/page_vma_mapped.c~mm-pvmw-check-possible-huge-pmd-map-by-transhuge_vma_suitable
+++ a/mm/page_vma_mapped.c
@@ -243,7 +243,7 @@ restart:
* cleared *pmd but not decremented compound_mapcount().
*/
if ((pvmw->flags & PVMW_SYNC) &&
- transparent_hugepage_active(vma) &&
+ transhuge_vma_suitable(vma, pvmw->address) &&
(pvmw->nr_pages >= HPAGE_PMD_NR)) {
spinlock_t *ptl = pmd_lock(mm, pvmw->pmd);
_
Patches currently in -mm which might be from shy828301@xxxxxxxxx are
sched-coredumph-clarify-the-use-of-mmf_vm_hugepage.patch
mm-khugepaged-remove-redundant-check-for-vm_no_khugepaged.patch
mm-khugepaged-skip-dax-vma.patch
mm-thp-only-regular-file-could-be-thp-eligible.patch
mm-khugepaged-make-khugepaged_enter-void-function.patch
mm-khugepaged-make-hugepage_vma_check-non-static.patch
mm-khugepaged-introduce-khugepaged_enter_vma-helper.patch
mm-mmap-register-suitable-readonly-file-vmas-for-khugepaged.patch
mm-rmap-use-the-correct-parameter-name-for-define_page_vma_walk.patch
mm-pvmw-check-possible-huge-pmd-map-by-transhuge_vma_suitable.patch
