From: Cyrill Gorcunov <[email protected]> Subject: mm: migration: do not lose soft dirty bit if page is in migration state
If page migration is turned on in config and the page is migrating, we may lose the soft dirty bit. If fork and mprotect are called on migrating pages (once migration is complete) pages do not obtain the soft dirty bit in the correspond pte entries. Fix it adding an appropriate test on swap entries. Signed-off-by: Cyrill Gorcunov <[email protected]> Cc: Pavel Emelyanov <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Matt Mackall <[email protected]> Cc: Xiao Guangrong <[email protected]> Cc: Marcelo Tosatti <[email protected]> Cc: KOSAKI Motohiro <[email protected]> Cc: Stephen Rothwell <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: "Aneesh Kumar K.V" <[email protected]> Cc: Naoya Horiguchi <[email protected]> Cc: Mel Gorman <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]> --- mm/memory.c | 2 ++ mm/migrate.c | 2 ++ mm/mprotect.c | 7 +++++-- 3 files changed, 9 insertions(+), 2 deletions(-) diff -puN mm/memory.c~mm-migration-do-not-lose-soft-dirty-bit-if-page-is-in-migration-state mm/memory.c --- a/mm/memory.c~mm-migration-do-not-lose-soft-dirty-bit-if-page-is-in-migration-state +++ a/mm/memory.c @@ -837,6 +837,8 @@ copy_one_pte(struct mm_struct *dst_mm, s */ make_migration_entry_read(&entry); pte = swp_entry_to_pte(entry); + if (pte_swp_soft_dirty(*src_pte)) + pte = pte_swp_mksoft_dirty(pte); set_pte_at(src_mm, addr, src_pte, pte); } } diff -puN mm/migrate.c~mm-migration-do-not-lose-soft-dirty-bit-if-page-is-in-migration-state mm/migrate.c --- a/mm/migrate.c~mm-migration-do-not-lose-soft-dirty-bit-if-page-is-in-migration-state +++ a/mm/migrate.c @@ -161,6 +161,8 @@ static int remove_migration_pte(struct p get_page(new); pte = pte_mkold(mk_pte(new, vma->vm_page_prot)); + if (pte_swp_soft_dirty(*ptep)) + pte = pte_mksoft_dirty(pte); if (is_write_migration_entry(entry)) pte = pte_mkwrite(pte); #ifdef CONFIG_HUGETLB_PAGE diff -puN mm/mprotect.c~mm-migration-do-not-lose-soft-dirty-bit-if-page-is-in-migration-state mm/mprotect.c --- a/mm/mprotect.c~mm-migration-do-not-lose-soft-dirty-bit-if-page-is-in-migration-state +++ a/mm/mprotect.c @@ -94,13 +94,16 @@ static unsigned long change_pte_range(st swp_entry_t entry = pte_to_swp_entry(oldpte); if (is_write_migration_entry(entry)) { + pte_t newpte; /* * A protection check is difficult so * just be safe and disable write */ make_migration_entry_read(&entry); - set_pte_at(mm, addr, pte, - swp_entry_to_pte(entry)); + newpte = swp_entry_to_pte(entry); + if (pte_swp_soft_dirty(oldpte)) + newpte = pte_swp_mksoft_dirty(newpte); + set_pte_at(mm, addr, pte, newpte); } pages++; } _ -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
