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mm, memcg: avoid unnecessary function call when memcg is disabled

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While profiling numa/core v16 with cgroup_disable=memory on the command
line, I noticed mem_cgroup_count_vm_event() still showed up as high as
0.60% in perftop.

This occurs because the function is called extremely often even when memcg
is disabled.

To fix this, inline the check for mem_cgroup_disabled() so we avoid the
unnecessary function call if memcg is disabled.

Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Glauber Costa <glommer@parallels.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
David Rientjes 2012-12-12 13:51:57 -08:00 committed by Linus Torvalds
parent 05b0afd73d
commit 68ae564bba
2 changed files with 12 additions and 3 deletions
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9
include/linux/memcontrol.h
View file

@ -181,7 +181,14 @@ unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
gfp_t gfp_mask, gfp_t gfp_mask,
unsigned long *total_scanned); unsigned long *total_scanned);
void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx); 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())
return;
__mem_cgroup_count_vm_event(mm, idx);
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE #ifdef CONFIG_TRANSPARENT_HUGEPAGE
void mem_cgroup_split_huge_fixup(struct page *head); void mem_cgroup_split_huge_fixup(struct page *head);
#endif #endif

6
mm/memcontrol.c
View file

@ -59,6 +59,8 @@
#include <trace/events/vmscan.h> #include <trace/events/vmscan.h>
struct cgroup_subsys mem_cgroup_subsys __read_mostly; struct cgroup_subsys mem_cgroup_subsys __read_mostly;
EXPORT_SYMBOL(mem_cgroup_subsys);
#define MEM_CGROUP_RECLAIM_RETRIES 5 #define MEM_CGROUP_RECLAIM_RETRIES 5
static struct mem_cgroup *root_mem_cgroup __read_mostly; static struct mem_cgroup *root_mem_cgroup __read_mostly;
@ -1015,7 +1017,7 @@ void mem_cgroup_iter_break(struct mem_cgroup *root,
iter != NULL; \ iter != NULL; \
iter = mem_cgroup_iter(NULL, iter, NULL)) iter = mem_cgroup_iter(NULL, iter, NULL))
void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx) void __mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx)
{ {
struct mem_cgroup *memcg; struct mem_cgroup *memcg;
@ -1040,7 +1042,7 @@ void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx)
out: out:
rcu_read_unlock(); rcu_read_unlock();
} }
EXPORT_SYMBOL(mem_cgroup_count_vm_event); EXPORT_SYMBOL(__mem_cgroup_count_vm_event);
/** /**
* mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg * mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg