[3.5.y.z extended stable] Patch "slub: Fix calculation of cpu slabs" has been added to staging queue
Luis Henriques
luis.henriques at canonical.com
Fri Feb 7 11:20:28 UTC 2014
This is a note to let you know that I have just added a patch titled
slub: Fix calculation of cpu slabs
to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree
which can be found at:
http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Luis
------
>From 7977d5109f10cb8dcc25bf4b178ffde80607ed12 Mon Sep 17 00:00:00 2001
From: Li Zefan <lizefan at huawei.com>
Date: Tue, 10 Sep 2013 11:43:37 +0800
Subject: slub: Fix calculation of cpu slabs
commit 8afb1474db4701d1ab80cd8251137a3260e6913e upstream.
/sys/kernel/slab/:t-0000048 # cat cpu_slabs
231 N0=16 N1=215
/sys/kernel/slab/:t-0000048 # cat slabs
145 N0=36 N1=109
See, the number of slabs is smaller than that of cpu slabs.
The bug was introduced by commit 49e2258586b423684f03c278149ab46d8f8b6700
("slub: per cpu cache for partial pages").
We should use page->pages instead of page->pobjects when calculating
the number of cpu partial slabs. This also fixes the mapping of slabs
and nodes.
As there's no variable storing the number of total/active objects in
cpu partial slabs, and we don't have user interfaces requiring those
statistics, I just add WARN_ON for those cases.
Acked-by: Christoph Lameter <cl at linux.com>
Reviewed-by: Wanpeng Li <liwanp at linux.vnet.ibm.com>
Signed-off-by: Li Zefan <lizefan at huawei.com>
Signed-off-by: Pekka Enberg <penberg at kernel.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
mm/slub.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/mm/slub.c b/mm/slub.c
index 8c691fa..ca056a6 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -4520,7 +4520,13 @@ static ssize_t show_slab_objects(struct kmem_cache *s,
page = c->partial;
if (page) {
- x = page->pobjects;
+ node = page_to_nid(page);
+ if (flags & SO_TOTAL)
+ WARN_ON_ONCE(1);
+ else if (flags & SO_OBJECTS)
+ WARN_ON_ONCE(1);
+ else
+ x = page->pages;
total += x;
nodes[node] += x;
}
--
1.8.3.2
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