* [PATCH 5/6] memcg: optimize memcg_get_hierarchical_limit
@ 2012-06-23 6:18 Wanpeng Li
2012-06-23 9:39 ` Johannes Weiner
2012-06-25 8:14 ` Glauber Costa
0 siblings, 2 replies; 3+ messages in thread
From: Wanpeng Li @ 2012-06-23 6:18 UTC (permalink / raw)
To: linux-mm
Cc: Michal Hocko, Johannes Weiner, Balbir Singh, KAMEZAWA Hiroyuki,
Andrew Morton, Mel Gorman, Minchan Kim, linux-kernel, cgroups,
Gavin Shan, Wanpeng Li
From: Wanpeng Li <liwp@linux.vnet.ibm.com>
Optimize memcg_get_hierarchical_limit to save cpu cycle.
Signed-off-by: Wanpeng Li <liwp.linux@gmail.com>
---
mm/memcontrol.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index c821e36..1ca79e2 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3917,9 +3917,9 @@ static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
- cgroup = memcg->css.cgroup;
if (!memcg->use_hierarchy)
goto out;
+ cgroup = memcg->css.cgroup;
while (cgroup->parent) {
cgroup = cgroup->parent;
--
1.7.9.5
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^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH 5/6] memcg: optimize memcg_get_hierarchical_limit
2012-06-23 6:18 [PATCH 5/6] memcg: optimize memcg_get_hierarchical_limit Wanpeng Li
@ 2012-06-23 9:39 ` Johannes Weiner
2012-06-25 8:14 ` Glauber Costa
1 sibling, 0 replies; 3+ messages in thread
From: Johannes Weiner @ 2012-06-23 9:39 UTC (permalink / raw)
To: Wanpeng Li
Cc: linux-mm, Michal Hocko, Balbir Singh, KAMEZAWA Hiroyuki,
Andrew Morton, Mel Gorman, Minchan Kim, linux-kernel, cgroups,
Gavin Shan
On Sat, Jun 23, 2012 at 02:18:17PM +0800, Wanpeng Li wrote:
> From: Wanpeng Li <liwp@linux.vnet.ibm.com>
>
> Optimize memcg_get_hierarchical_limit to save cpu cycle.
>
> Signed-off-by: Wanpeng Li <liwp.linux@gmail.com>
I really would have thought the compiler would detect it, but this
patch actually does switch around move and jump.
But this is miniscule and anything but a fastpath...
> ---
> mm/memcontrol.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index c821e36..1ca79e2 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -3917,9 +3917,9 @@ static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
>
> min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
> min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
> - cgroup = memcg->css.cgroup;
> if (!memcg->use_hierarchy)
> goto out;
> + cgroup = memcg->css.cgroup;
>
> while (cgroup->parent) {
> cgroup = cgroup->parent;
> --
> 1.7.9.5
>
--
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^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH 5/6] memcg: optimize memcg_get_hierarchical_limit
2012-06-23 6:18 [PATCH 5/6] memcg: optimize memcg_get_hierarchical_limit Wanpeng Li
2012-06-23 9:39 ` Johannes Weiner
@ 2012-06-25 8:14 ` Glauber Costa
1 sibling, 0 replies; 3+ messages in thread
From: Glauber Costa @ 2012-06-25 8:14 UTC (permalink / raw)
To: Wanpeng Li
Cc: linux-mm, Michal Hocko, Johannes Weiner, Balbir Singh,
KAMEZAWA Hiroyuki, Andrew Morton, Mel Gorman, Minchan Kim,
linux-kernel, cgroups, Gavin Shan
On 06/23/2012 10:18 AM, Wanpeng Li wrote:
> From: Wanpeng Li <liwp@linux.vnet.ibm.com>
>
> Optimize memcg_get_hierarchical_limit to save cpu cycle.
>
> Signed-off-by: Wanpeng Li <liwp.linux@gmail.com>
> ---
> mm/memcontrol.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index c821e36..1ca79e2 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -3917,9 +3917,9 @@ static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
>
> min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
> min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
> - cgroup = memcg->css.cgroup;
> if (!memcg->use_hierarchy)
> goto out;
> + cgroup = memcg->css.cgroup;
>
> while (cgroup->parent) {
> cgroup = cgroup->parent;
>
Seriously, this saves nothing.
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^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2012-06-25 8:17 UTC | newest]
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2012-06-23 6:18 [PATCH 5/6] memcg: optimize memcg_get_hierarchical_limit Wanpeng Li
2012-06-23 9:39 ` Johannes Weiner
2012-06-25 8:14 ` Glauber Costa
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