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Date: Fri, 11 Mar 2016 11:29:25 +0100
From: Michal Hocko <mhocko@kernel.org>
To: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
        Johannes Weiner <hannes@cmpxchg.org>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: memcontrol: zap oom_info_lock
Message-ID: <20160311102925.GG27701@dhcp22.suse.cz>
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On Fri 11-03-16 13:11:23, Vladimir Davydov wrote:
> mem_cgroup_print_oom_info is always called under oom_lock, so
> oom_info_lock is redundant.
> 
> Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com>

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

> ---
>  mm/memcontrol.c | 4 ----
>  1 file changed, 4 deletions(-)
> 
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index fa7bf354ae32..36db05fa8acb 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -1150,12 +1150,9 @@ static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg)
>   */
>  void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
>  {
> -	/* oom_info_lock ensures that parallel ooms do not interleave */
> -	static DEFINE_MUTEX(oom_info_lock);
>  	struct mem_cgroup *iter;
>  	unsigned int i;
>  
> -	mutex_lock(&oom_info_lock);
>  	rcu_read_lock();
>  
>  	if (p) {
> @@ -1199,7 +1196,6 @@ void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
>  
>  		pr_cont("\n");
>  	}
> -	mutex_unlock(&oom_info_lock);
>  }
>  
>  /*
> -- 
> 2.1.4

-- 
Michal Hocko
SUSE Labs