From: Mel Gorman <mgorman@suse.de>
Date: Thu, 7 Feb 2013 01:26:48 +0000 (+1100)
Subject: mm: numa: handle side-effects in count_vm_numa_events() for !CONFIG_NUMA_BALANCING
X-Git-Tag: next-20130218~1^2~385
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=4f111b4424397737e2de132bfdb44dc161fbe87c;p=karo-tx-linux.git

mm: numa: handle side-effects in count_vm_numa_events() for !CONFIG_NUMA_BALANCING

The current definitions for count_vm_numa_events() is wrong for
!CONFIG_NUMA_BALANCING as the following would miss the side-effect.

	count_vm_numa_events(NUMA_FOO, bar++);

There are no such users of count_vm_numa_events() but this patch fixes it
as it is a potential pitfall.  Ideally both would be converted to static
inline but NUMA_PTE_UPDATES is not defined if !CONFIG_NUMA_BALANCING and
creating dummy constants just to have a static inline would be similarly
clumsy.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Simon Jeons <simon.jeons@gmail.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
index a13291f7da88..5fd71a7d0dfd 100644
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h
@@ -85,7 +85,7 @@ static inline void vm_events_fold_cpu(int cpu)
 #define count_vm_numa_events(x, y) count_vm_events(x, y)
 #else
 #define count_vm_numa_event(x) do {} while (0)
-#define count_vm_numa_events(x, y) do {} while (0)
+#define count_vm_numa_events(x, y) do { (void)(y); } while (0)
 #endif /* CONFIG_NUMA_BALANCING */
 
 #define __count_zone_vm_events(item, zone, delta) \