diff options
| author | Paul Gofman <pgofman@codeweavers.com> | 2024-02-06 13:48:01 +0500 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-02-22 10:24:55 -0800 |
| commit | 055267feaecc9c6c53f128aa50746f64c4ef5ca2 (patch) | |
| tree | a53748b7b3f09a990ad43cf4ad1212068456f4b6 /mm/migrate.c | |
| parent | a230c20e63efef3daab510979898b25a0e446b36 (diff) | |
| download | linux-055267feaecc9c6c53f128aa50746f64c4ef5ca2.tar.gz | |
mm/migrate: preserve exact soft-dirty state
pte_mkdirty() sets both _PAGE_DIRTY and _PAGE_SOFT_DIRTY bits. The
_PAGE_SOFT_DIRTY can get set even if it wasn't set on original page before
migration. This makes non-soft-dirty pages soft-dirty just because of
migration/compaction. Clear the _PAGE_SOFT_DIRTY flag if it wasn't set on
original page.
By definition of soft-dirty feature, there can be spurious soft-dirty
pages because of kernel's internal activity such as VMA merging or
migration/compaction. This patch is eliminating the spurious soft-dirty
pages because of migration/compaction.
Link: https://lkml.kernel.org/r/20240206084838.34560-1-usama.anjum@collabora.com
Signed-off-by: Paul Gofman <pgofman@codeweavers.com>
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Acked-by: Andrei Vagin <avagin@gmail.com>
Cc: Michał Mirosław <emmir@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/migrate.c')
| -rw-r--r-- | mm/migrate.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/mm/migrate.c b/mm/migrate.c index cc9f2bcd73b49..05d6ca4373215 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -211,14 +211,17 @@ static bool remove_migration_pte(struct folio *folio, folio_get(folio); pte = mk_pte(new, READ_ONCE(vma->vm_page_prot)); old_pte = ptep_get(pvmw.pte); - if (pte_swp_soft_dirty(old_pte)) - pte = pte_mksoft_dirty(pte); entry = pte_to_swp_entry(old_pte); if (!is_migration_entry_young(entry)) pte = pte_mkold(pte); if (folio_test_dirty(folio) && is_migration_entry_dirty(entry)) pte = pte_mkdirty(pte); + if (pte_swp_soft_dirty(old_pte)) + pte = pte_mksoft_dirty(pte); + else + pte = pte_clear_soft_dirty(pte); + if (is_writable_migration_entry(entry)) pte = pte_mkwrite(pte, vma); else if (pte_swp_uffd_wp(old_pte)) |