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| author | Peter Xu <peterx@redhat.com> | 2022-08-11 18:13:28 +0200 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2022-09-27 04:46:05 +0200 |
| commit | 0ccf7f168e17bb7eb5a322397ba5a841f4fbaccb (patch) | |
| tree | c7f8491234fc2a42dce4f1071fc346168732225a /mm/huge_memory.c | |
| parent | mm/swap: add swp_offset_pfn() to fetch PFN from swap entry (diff) | |
| download | linux-0ccf7f168e17bb7eb5a322397ba5a841f4fbaccb.tar.xz linux-0ccf7f168e17bb7eb5a322397ba5a841f4fbaccb.zip | |
mm/thp: carry over dirty bit when thp splits on pmd
Carry over the dirty bit from pmd to pte when a huge pmd splits. It
shouldn't be a correctness issue since when pmd_dirty() we'll have the
page marked dirty anyway, however having dirty bit carried over helps the
next initial writes of split ptes on some archs like x86.
Link: https://lkml.kernel.org/r/20220811161331.37055-5-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Huang Ying <ying.huang@intel.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andi Kleen <andi.kleen@intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/huge_memory.c')
| -rw-r--r-- | mm/huge_memory.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 7bf2299cb24b..b4666774abf0 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2037,7 +2037,7 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, pgtable_t pgtable; pmd_t old_pmd, _pmd; bool young, write, soft_dirty, pmd_migration = false, uffd_wp = false; - bool anon_exclusive = false; + bool anon_exclusive = false, dirty = false; unsigned long addr; int i; @@ -2126,8 +2126,10 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, uffd_wp = pmd_swp_uffd_wp(old_pmd); } else { page = pmd_page(old_pmd); - if (pmd_dirty(old_pmd)) + if (pmd_dirty(old_pmd)) { + dirty = true; SetPageDirty(page); + } write = pmd_write(old_pmd); young = pmd_young(old_pmd); soft_dirty = pmd_soft_dirty(old_pmd); @@ -2195,6 +2197,9 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, entry = pte_wrprotect(entry); if (!young) entry = pte_mkold(entry); + /* NOTE: this may set soft-dirty too on some archs */ + if (dirty) + entry = pte_mkdirty(entry); if (soft_dirty) entry = pte_mksoft_dirty(entry); if (uffd_wp) |