The patch titled
Subject: dm bufio: fully initialize shrinker
has been added to the -mm tree. Its filename is
dm-bufio-fully-initialize-shrinker.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/dm-bufio-fully-initialize-shrinker.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/dm-bufio-fully-initialize-shrinker.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Greg Thelen <[email protected]>
Subject: dm bufio: fully initialize shrinker
1d3d4437eae1 ("vmscan: per-node deferred work") added a flags field to
struct shrinker assuming that all shrinkers were zero filled. The dm
bufio shrinker is not zero filled, which leaves arbitrary kmalloc() data
in flags. So far the only defined flags bit is SHRINKER_NUMA_AWARE.
But there are proposed patches which add other bits to shrinker.flags
(e.g. memcg awareness).
Rather than simply initializing the shrinker, this patch uses kzalloc()
when allocating the dm_bufio_client to ensure that the embedded shrinker
and any other similar structures are zeroed.
This fixes theoretical over aggressive shrinking of dm bufio objects.
If the uninitialized dm_bufio_client.shrinker.flags contains
SHRINKER_NUMA_AWARE then shrink_slab() would call the dm shrinker for
each numa node rather than just once. This has been broken since 3.12.
Signed-off-by: Greg Thelen <[email protected]>
Cc: Alasdair Kergon <[email protected]>
Cc: Mike Snitzer <[email protected]>
Cc: Neil Brown <[email protected]>
Cc: Vladimir Davydov <[email protected]>
Cc: Dave Chinner <[email protected]>
Cc: <[email protected]> [3.12+]
Signed-off-by: Andrew Morton <[email protected]>
---
drivers/md/dm-bufio.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN drivers/md/dm-bufio.c~dm-bufio-fully-initialize-shrinker
drivers/md/dm-bufio.c
--- a/drivers/md/dm-bufio.c~dm-bufio-fully-initialize-shrinker
+++ a/drivers/md/dm-bufio.c
@@ -1541,7 +1541,7 @@ struct dm_bufio_client *dm_bufio_client_
BUG_ON(block_size < 1 << SECTOR_SHIFT ||
(block_size & (block_size - 1)));
- c = kmalloc(sizeof(*c), GFP_KERNEL);
+ c = kzalloc(sizeof(*c), GFP_KERNEL);
if (!c) {
r = -ENOMEM;
goto bad_client;
_
Patches currently in -mm which might be from [email protected] are
dm-bufio-fully-initialize-shrinker.patch
memcg-remove-lookup_cgroup_page-prototype.patch
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
