Re: [patch] mm, memcg: avoid unnecessary function call when memcgis disabled fix

From: Kamezawa Hiroyuki
Date: Tue Nov 20 2012 - 23:11:26 EST


(2012/11/21 11:48), David Rientjes wrote:
Move the check for !mm out of line as suggested by Andrew.

Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>

Thank you very much !

Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>


---
include/linux/memcontrol.h | 2 +-
mm/memcontrol.c | 3 +++
2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -185,7 +185,7 @@ void __mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx);
static inline void mem_cgroup_count_vm_event(struct mm_struct *mm,
enum vm_event_item idx)
{
- if (mem_cgroup_disabled() || !mm)
+ if (mem_cgroup_disabled())
return;
__mem_cgroup_count_vm_event(mm, idx);
}
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1021,6 +1021,9 @@ void __mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx)
{
struct mem_cgroup *memcg;

+ if (!mm)
+ return;
+
rcu_read_lock();
memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
if (unlikely(!memcg))



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