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().
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: stable@xxxxxxxxxx [2.6.37]
---
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.
mm/migrate.c | 23 ++++++-----------------
1 file changed, 6 insertions(+), 17 deletions(-)
--- 2.6.37/mm/migrate.c 2011-01-10 17:23:39.000000000 -0800
+++ linux/mm/migrate.c 2011-01-10 22:01:16.000000000 -0800
@@ -806,7 +806,6 @@ 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)
@@ -821,12 +820,10 @@ 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);
}
}
@@ -838,16 +835,8 @@ 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);
--
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