The patch titled
mm: fix hugepage migration
has been added to the -mm tree. Its filename is
mm-fix-hugepage-migration.patch
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out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: mm: fix hugepage migration
From: Hugh Dickins <hughd@xxxxxxxxxx>
2.6.37 added an unmap_and_move_huge_page() for memory failure recovery,
but its anon_vma handling was still based around the 2.6.35 conventions.
Update it to use page_lock_anon_vma, get_anon_vma, page_unlock_anon_vma,
drop_anon_vma in the same way as we're now changing unmap_and_move().
I don't particularly like to propose this for stable when I've not seen
its problems in practice nor tested the solution: but it's clearly out of
synch at present.
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Mel Gorman <mel@xxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: "Jun'ichi Nomura" <j-nomura@xxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxx> [2.6.37, 2.6.36]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/migrate.c | 23 ++++++-----------------
1 file changed, 6 insertions(+), 17 deletions(-)
diff -puN mm/migrate.c~mm-fix-hugepage-migration mm/migrate.c
--- a/mm/migrate.c~mm-fix-hugepage-migration
+++ a/mm/migrate.c
@@ -828,7 +828,6 @@ static int unmap_and_move_huge_page(new_
int rc = 0;
int *result = NULL;
struct page *new_hpage = get_new_page(hpage, private, &result);
- int rcu_locked = 0;
struct anon_vma *anon_vma = NULL;
if (!new_hpage)
@@ -843,12 +842,10 @@ static int unmap_and_move_huge_page(new_
}
if (PageAnon(hpage)) {
- rcu_read_lock();
- rcu_locked = 1;
-
- if (page_mapped(hpage)) {
- anon_vma = page_anon_vma(hpage);
- atomic_inc(&anon_vma->external_refcount);
+ anon_vma = page_lock_anon_vma(hpage);
+ if (anon_vma) {
+ get_anon_vma(anon_vma);
+ page_unlock_anon_vma(anon_vma);
}
}
@@ -860,16 +857,8 @@ static int unmap_and_move_huge_page(new_
if (rc)
remove_migration_ptes(hpage, hpage);
- if (anon_vma && atomic_dec_and_lock(&anon_vma->external_refcount,
- &anon_vma->lock)) {
- int empty = list_empty(&anon_vma->head);
- spin_unlock(&anon_vma->lock);
- if (empty)
- anon_vma_free(anon_vma);
- }
-
- if (rcu_locked)
- rcu_read_unlock();
+ if (anon_vma)
+ drop_anon_vma(anon_vma);
out:
unlock_page(hpage);
_
Patches currently in -mm which might be from hughd@xxxxxxxxxx are
origin.patch
mm-vmap-area-cache-fix.patch
mm-vmscan-reclaim-order-0-and-use-compaction-instead-of-lumpy-reclaim-avoid-a-potential-deadlock-due-to-lock_page-during-direct-compaction.patch
mm-vmscan-reclaim-order-0-and-use-compaction-instead-of-lumpy-reclaim-avoid-a-potential-deadlock-due-to-lock_page-during-direct-compaction-fix.patch
do_wp_page-remove-the-reuse-flag.patch
do_wp_page-clarify-dirty_page-handling.patch
mlock-avoid-dirtying-pages-and-triggering-writeback.patch
mlock-only-hold-mmap_sem-in-shared-mode-when-faulting-in-pages.patch
mm-add-foll_mlock-follow_page-flag.patch
mm-move-vm_locked-check-to-__mlock_vma_pages_range.patch
mlock-do-not-hold-mmap_sem-for-extended-periods-of-time.patch
mlock-do-not-hold-mmap_sem-for-extended-periods-of-time-fix.patch
thp-ksm-free-swap-when-swapcache-page-is-replaced.patch
thp-transparent-hugepage-core-fixlet.patch
thp-ksm-on-thp.patch
thp-add-compound_trans_head-helper.patch
ksm-drain-pagevecs-to-lru.patch
mm-fix-migration-hangs-on-anon_vma-lock.patch
mm-fix-hugepage-migration.patch
memcg-fix-memory-migration-of-shmem-swapcache.patch
prio_tree-debugging-patch.patch
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