From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755245Ab3JHJDV (ORCPT ); Tue, 8 Oct 2013 05:03:21 -0400 Received: from mail-la0-f50.google.com ([209.85.215.50]:44555 "EHLO mail-la0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754030Ab3JHJCj (ORCPT ); Tue, 8 Oct 2013 05:02:39 -0400 Message-Id: <20131008090236.951114091@gmail.com> User-Agent: quilt/0.60-1 Date: Tue, 08 Oct 2013 13:00:20 +0400 From: Cyrill Gorcunov To: akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Cyrill Gorcunov , Pavel Emelyanov , Andy Lutomirski , Matt Mackall , Xiao Guangrong , Marcelo Tosatti , KOSAKI Motohiro , Stephen Rothwell , Peter Zijlstra , "Aneesh Kumar K.V" Subject: [patch 1/3] [PATCH] mm: migration -- Do not loose soft dirty bit if page is in migration state References: <20131008090019.527108154@gmail.com> Content-Disposition: inline; filename=pte-sft-dirty-migration-fix Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If page migration is turne on in the config and the page is migrating, we may loose soft dirty bit. If fork and mprotect if called on migrating pages (once migration is complete) pages do not obtain soft dirty bit in correspond pte entries. Fix it adding appropriate test on swap entries. Signed-off-by: Cyrill Gorcunov Cc: Pavel Emelyanov Cc: Andy Lutomirski Cc: Andrew Morton Cc: Matt Mackall Cc: Xiao Guangrong Cc: Marcelo Tosatti Cc: KOSAKI Motohiro Cc: Stephen Rothwell Cc: Peter Zijlstra Cc: "Aneesh Kumar K.V" --- mm/memory.c | 2 ++ mm/migrate.c | 2 ++ mm/mprotect.c | 7 +++++-- 3 files changed, 9 insertions(+), 2 deletions(-) Index: linux-2.6.git/mm/memory.c =================================================================== --- linux-2.6.git.orig/mm/memory.c +++ linux-2.6.git/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); } } Index: linux-2.6.git/mm/migrate.c =================================================================== --- linux-2.6.git.orig/mm/migrate.c +++ linux-2.6.git/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 Index: linux-2.6.git/mm/mprotect.c =================================================================== --- linux-2.6.git.orig/mm/mprotect.c +++ linux-2.6.git/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++; }