3.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Li Zefan <lize...@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 <c...@linux.com>
Reviewed-by: Wanpeng Li <liw...@linux.vnet.ibm.com>
Signed-off-by: Li Zefan <lize...@huawei.com>
Signed-off-by: Pekka Enberg <penb...@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 mm/slub.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

--- a/mm/slub.c
+++ b/mm/slub.c
@@ -4272,7 +4272,13 @@ static ssize_t show_slab_objects(struct
 
                        page = ACCESS_ONCE(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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