[PATCH] memcg: remove pcp_counter_lock

[PATCH] memcg: remove pcp_counter_lock

[Greg Thelen]

Commit 733a572e66d2 ("memcg: make mem_cgroup_read_{stat|event}() iterate
possible cpus instead of online") removed the last use of the per memcg
pcp_counter_lock but forgot to remove the variable.

Kill the vestigial variable.

Signed-off-by: Greg Thelen <gthelen@google.com>
---
 include/linux/memcontrol.h | 1 -
 mm/memcontrol.c            | 1 -
 2 files changed, 2 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index ad800e62cb7a..6452ff4c463f 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -242,7 +242,6 @@ struct mem_cgroup {
 	 * percpu counter.
 	 */
 	struct mem_cgroup_stat_cpu __percpu *stat;
-	spinlock_t pcp_counter_lock;
 
 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET)
 	struct cg_proto tcp_mem;
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 6ddaeba34e09..da21143550c0 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4179,7 +4179,6 @@ static struct mem_cgroup *mem_cgroup_alloc(void)
 	if (memcg_wb_domain_init(memcg, GFP_KERNEL))
 		goto out_free_stat;
 
-	spin_lock_init(&memcg->pcp_counter_lock);
 	return memcg;
 
 out_free_stat:
-- 
2.6.0.rc0.131.gf624c3d

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Re: [PATCH] memcg: remove pcp_counter_lock

[Michal Hocko]

On Tue 22-09-15 19:41:46, Greg Thelen wrote:
> Commit 733a572e66d2 ("memcg: make mem_cgroup_read_{stat|event}() iterate
> possible cpus instead of online") removed the last use of the per memcg
> pcp_counter_lock but forgot to remove the variable.
> 
> Kill the vestigial variable.
> 
> Signed-off-by: Greg Thelen <gthelen@google.com>

Acked-by: Michal Hocko <mhocko@suse.com>

> ---
>  include/linux/memcontrol.h | 1 -
>  mm/memcontrol.c            | 1 -
>  2 files changed, 2 deletions(-)
> 
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index ad800e62cb7a..6452ff4c463f 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -242,7 +242,6 @@ struct mem_cgroup {
>  	 * percpu counter.
>  	 */
>  	struct mem_cgroup_stat_cpu __percpu *stat;
> -	spinlock_t pcp_counter_lock;
>  
>  #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET)
>  	struct cg_proto tcp_mem;
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 6ddaeba34e09..da21143550c0 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -4179,7 +4179,6 @@ static struct mem_cgroup *mem_cgroup_alloc(void)
>  	if (memcg_wb_domain_init(memcg, GFP_KERNEL))
>  		goto out_free_stat;
>  
> -	spin_lock_init(&memcg->pcp_counter_lock);
>  	return memcg;
>  
>  out_free_stat:
> -- 
> 2.6.0.rc0.131.gf624c3d

-- 
Michal Hocko
SUSE Labs

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Re: [PATCH] memcg: remove pcp_counter_lock

[Johannes Weiner]

On Tue, Sep 22, 2015 at 07:41:46PM -0700, Greg Thelen wrote:
> Commit 733a572e66d2 ("memcg: make mem_cgroup_read_{stat|event}() iterate
> possible cpus instead of online") removed the last use of the per memcg
> pcp_counter_lock but forgot to remove the variable.
> 
> Kill the vestigial variable.
> 
> Signed-off-by: Greg Thelen <gthelen@google.com>

Acked-by: Johannes Weiner <hannes@cmpxchg.org>

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