diff options
| author | Hugh Dickins <hughd@google.com> | 2012-04-23 11:14:50 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-04-23 18:19:22 -0700 |
| commit | aca50bd3b4c4bb5528a1878158ba7abce41de534 (patch) | |
| tree | 697c1d89d8d8a75878dc5c5c70aeb14cd72f80fa /mm | |
| parent | e895bd7992df1ebd1e0c28f7965520482bc83b74 (diff) | |
mm: fix s390 BUG by __set_page_dirty_no_writeback on swap
Mel reports a BUG_ON(slot == NULL) in radix_tree_tag_set() on s390
3.0.13: called from __set_page_dirty_nobuffers() when page_remove_rmap()
tries to transfer dirty flag from s390 storage key to struct page and
radix_tree.
That would be because of reclaim's shrink_page_list() calling
add_to_swap() on this page at the same time: first PageSwapCache is set
(causing page_mapping(page) to appear as &swapper_space), then
page->private set, then tree_lock taken, then page inserted into
radix_tree - so there's an interval before taking the lock when the
radix_tree slot is empty.
We could fix this by moving __add_to_swap_cache()'s spin_lock_irq up
before the SetPageSwapCache. But a better fix is simply to do what's
five years overdue: Ken Chen introduced __set_page_dirty_no_writeback()
(if !PageDirty TestSetPageDirty) for tmpfs to skip all the radix_tree
overhead, and swap is just the same - it ignores the radix_tree tag, and
does not participate in dirty page accounting, so should be using
__set_page_dirty_no_writeback() too.
s390 testing now confirms that this does indeed fix the problem.
Reported-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Ken Chen <kenchen@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/swap_state.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/swap_state.c b/mm/swap_state.c index 9d3dd3763cf..4c5ff7f284d 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c @@ -26,7 +26,7 @@ */ static const struct address_space_operations swap_aops = { .writepage = swap_writepage, - .set_page_dirty = __set_page_dirty_nobuffers, + .set_page_dirty = __set_page_dirty_no_writeback, .migratepage = migrate_page, }; |