| From | Ben Hutchings <> | Date | Mon, 31 Mar 2014 00:23:35 +0100 | Subject | [PATCH 3.2 014/200] slub: Fix calculation of cpu slabs |
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3.2.56-rc1 review patch. If anyone has any objections, please let me know.
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From: Li Zefan <lizefan@huawei.com>
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@linux.com> Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com> Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Pekka Enberg <penberg@kernel.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- mm/slub.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
--- a/mm/slub.c +++ b/mm/slub.c @@ -4483,7 +4483,13 @@ static ssize_t show_slab_objects(struct 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; }
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