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Date: Fri, 21 Sep 2012 13:22:20 -0700
From: Tejun Heo <tj@kernel.org>
To: Glauber Costa <glommer@parallels.com>
Cc: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
        kamezawa.hiroyu@jp.fujitsu.com, devel@openvz.org, linux-mm@kvack.org,
        Suleiman Souhlal <suleiman@google.com>,
        Frederic Weisbecker <fweisbec@gmail.com>, Mel Gorman <mgorman@suse.de>,
        David Rientjes <rientjes@google.com>, Christoph Lameter <cl@linux.com>,
        Pekka Enberg <penberg@cs.helsinki.fi>, Michal Hocko <mhocko@suse.cz>,
        Johannes Weiner <hannes@cmpxchg.org>
Subject: Re: [PATCH v3 11/16] memcg: destroy memcg caches
Message-ID: <20120921202220.GO7264@google.com>
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 <1347977530-29755-12-git-send-email-glommer@parallels.com>
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Hello, Glauber.

On Tue, Sep 18, 2012 at 06:12:05PM +0400, Glauber Costa wrote:
> +static LIST_HEAD(destroyed_caches);
> +
> +static void kmem_cache_destroy_work_func(struct work_struct *w)
> +{
> +	struct kmem_cache *cachep;
> +	struct mem_cgroup_cache_params *p, *tmp;
> +	unsigned long flags;
> +	LIST_HEAD(del_unlocked);
> +
> +	spin_lock_irqsave(&cache_queue_lock, flags);
> +	list_for_each_entry_safe(p, tmp, &destroyed_caches, destroyed_list) {
> +		cachep = container_of(p, struct kmem_cache, memcg_params);
> +		list_move(&cachep->memcg_params.destroyed_list, &del_unlocked);
> +	}
> +	spin_unlock_irqrestore(&cache_queue_lock, flags);
> +
> +	list_for_each_entry_safe(p, tmp, &del_unlocked, destroyed_list) {
> +		cachep = container_of(p, struct kmem_cache, memcg_params);
> +		list_del(&cachep->memcg_params.destroyed_list);
> +		if (!atomic_read(&cachep->memcg_params.nr_pages)) {
> +			mem_cgroup_put(cachep->memcg_params.memcg);
> +			kmem_cache_destroy(cachep);
> +		}
> +	}
> +}
> +static DECLARE_WORK(kmem_cache_destroy_work, kmem_cache_destroy_work_func);

Again, please don't build your own worklist.  Just embed a work item
into mem_cgroup_cache_params and manipulate them.  No need to
duplicate what workqueue already implements.

Thanks.

-- 
tejun