The patch titled
Subject: mm/migrate: preserve soft dirty in remove_migration_pte()
has been added to the -mm tree. Its filename is
mm-migrate-preserve-soft-dirty-in-remove_migration_pte.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-migrate-preserve-soft-dirty-in-remove_migration_pte.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-migrate-preserve-soft-dirty-in-remove_migration_pte.patch
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------------------------------------------------------
From: Ralph Campbell <rcampbell@xxxxxxxxxx>
Subject: mm/migrate: preserve soft dirty in remove_migration_pte()
The code to remove a migration PTE and replace it with a device private
PTE was not copying the soft dirty bit from the migration entry. This
could lead to page contents not being marked dirty when faulting the page
back from device private memory.
Link: https://lkml.kernel.org/r/20200831212222.22409-3-rcampbell@xxxxxxxxxx
Signed-off-by: Ralph Campbell <rcampbell@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Cc: Jerome Glisse <jglisse@xxxxxxxxxx>
Cc: Alistair Popple <apopple@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxxxx>
Cc: Bharata B Rao <bharata@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/migrate.c | 2 ++
1 file changed, 2 insertions(+)
--- a/mm/migrate.c~mm-migrate-preserve-soft-dirty-in-remove_migration_pte
+++ a/mm/migrate.c
@@ -249,6 +249,8 @@ static bool remove_migration_pte(struct
if (unlikely(is_device_private_page(new))) {
entry = make_device_private_entry(new, pte_write(pte));
pte = swp_entry_to_pte(entry);
+ if (pte_swp_soft_dirty(*pvmw.pte))
+ pte = pte_swp_mksoft_dirty(pte);
if (pte_swp_uffd_wp(*pvmw.pte))
pte = pte_swp_mkuffd_wp(pte);
}
_
Patches currently in -mm which might be from rcampbell@xxxxxxxxxx are
mm-migrate-remove-unnecessary-is_zone_device_page-check.patch
mm-migrate-preserve-soft-dirty-in-remove_migration_pte.patch
mm-thp-fix-__split_huge_pmd_locked-for-migration-pmd.patch
mm-test-use-the-new-skip-macro.patch
mm-migrate-remove-cpages-in-migrate_vma_finalize.patch
mm-migrate-remove-obsolete-comment-about-device-public.patch
