slub: No need for per node slab counters if !SLUB_DEBUG

The per node counters are used mainly for showing data through the sysfs API.
If that API is not compiled in then there is no point in keeping track of this
data. Disable counters for the number of slabs and the number of total slabs
if !SLUB_DEBUG. Incrementing the per node counters is also accessing a
potentially contended cacheline so this could actually be a performance
benefit to embedded systems.

SLABINFO support is also affected. It now must depends on SLUB_DEBUG (which
is on by default).

Patch also avoids a check for a NULL kmem_cache_node pointer in new_slab()
if the system is not compiled with NUMA support.

[penberg@cs.helsinki.fi: fix oops and move ->nr_slabs into CONFIG_SLUB_DEBUG]
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>

1 files changed, 1 insertions, 1 deletions

diff --git a/init/Kconfig b/init/Kconfig
index a97924bc5b8d..7fccf09bb95a 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -763,7 +763,7 @@ endmenu		# General setup
 config SLABINFO
         bool
         depends on PROC_FS
-        depends on SLAB || SLUB
+        depends on SLAB || SLUB_DEBUG
         default y
 
 config RT_MUTEXES