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authorHugh Dickins <hughd@google.com>2011-01-13 15:47:31 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2011-01-13 17:32:49 -0800
commitfd4a4663db293bfd5dc20fb4113977f62895e550 (patch)
treea161c087d714042b5402b858b9a6ee75392ecab2
parent1ce82b69e96c838d007f316b8347b911fdfa9842 (diff)
mm: fix hugepage migration
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@google.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Rik van Riel <riel@redhat.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: "Jun'ichi Nomura" <j-nomura@ce.jp.nec.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: <stable@kernel.org> [2.6.37, 2.6.36] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/migrate.c23
1 files changed, 6 insertions, 17 deletions
diff --git a/mm/migrate.c b/mm/migrate.c
index a20cf12eded..5b7d1fd2962 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -827,7 +827,6 @@ static int unmap_and_move_huge_page(new_page_t get_new_page,
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)
@@ -842,12 +841,10 @@ static int unmap_and_move_huge_page(new_page_t get_new_page,
}
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);
}
}
@@ -859,16 +856,8 @@ static int unmap_and_move_huge_page(new_page_t get_new_page,
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);