This is a note to let you know that I've just added the patch titled
mm: migration: do not lose soft dirty bit if page is in migration state
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-migration-do-not-lose-soft-dirty-bit-if-page-is-in-migration-state.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From c3d16e16522fe3fe8759735850a0676da18f4b1d Mon Sep 17 00:00:00 2001
From: Cyrill Gorcunov <gorcunov@xxxxxxxxx>
Date: Wed, 16 Oct 2013 13:46:51 -0700
Subject: mm: migration: do not lose soft dirty bit if page is in migration state
From: Cyrill Gorcunov <gorcunov@xxxxxxxxx>
commit c3d16e16522fe3fe8759735850a0676da18f4b1d upstream.
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 <gorcunov@xxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Matt Mackall <mpm@xxxxxxxxxxx>
Cc: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxxxxxx>
Cc: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxx>
Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Mel Gorman <mel@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/memory.c | 2 ++
mm/migrate.c | 2 ++
mm/mprotect.c | 7 +++++--
3 files changed, 9 insertions(+), 2 deletions(-)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -876,6 +876,8 @@ 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);
}
}
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -139,6 +139,8 @@ 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
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -64,13 +64,16 @@ static void change_pte_range(struct mm_s
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);
}
}
} while (pte++, addr += PAGE_SIZE, addr != end);
Patches currently in stable-queue which might be from gorcunov@xxxxxxxxx are
queue-3.4/mm-migration-do-not-lose-soft-dirty-bit-if-page-is-in-migration-state.patch
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