Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936196Ab3DHOPz (ORCPT ); Mon, 8 Apr 2013 10:15:55 -0400 Received: from cantor2.suse.de ([195.135.220.15]:32994 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935411Ab3DHOPn (ORCPT ); Mon, 8 Apr 2013 10:15:43 -0400 Date: Mon, 8 Apr 2013 16:15:40 +0200 From: Michal Hocko To: Li Zefan Cc: Andrew Morton , Tejun Heo , Glauber Costa , KAMEZAWA Hiroyuki , Johannes Weiner , LKML , Cgroups , linux-mm@kvack.org, Hugh Dickins Subject: Re: [PATCH 12/12] memcg: don't need to free memcg via RCU or workqueue Message-ID: <20130408141540.GG17178@dhcp22.suse.cz> References: <5162648B.9070802@huawei.com> <51626570.8000400@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <51626570.8000400@huawei.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3465 Lines: 110 On Mon 08-04-13 14:36:32, Li Zefan wrote: > Now memcg has the same life cycle with its corresponding cgroup, and > a cgroup is freed via RCU and then mem_cgroup_css_free() is called > in a work function, so we can simply call __mem_cgroup_free() in > mem_cgroup_css_free(). > > This actually reverts 59927fb984de1703c67bc640c3e522d8b5276c73 > ("memcg: free mem_cgroup by RCU to fix oops"). > > Cc: Hugh Dickins > Signed-off-by: Li Zefan OK, makes sense after the previous changes. Acked-by: Michal Hocko > --- > mm/memcontrol.c | 51 +++++---------------------------------------------- > 1 file changed, 5 insertions(+), 46 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index a6d44bc..5aa6e91 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -261,28 +261,10 @@ struct mem_cgroup { > */ > struct res_counter res; > > - union { > - /* > - * the counter to account for mem+swap usage. > - */ > - struct res_counter memsw; > - > - /* > - * rcu_freeing is used only when freeing struct mem_cgroup, > - * so put it into a union to avoid wasting more memory. > - * It must be disjoint from the css field. It could be > - * in a union with the res field, but res plays a much > - * larger part in mem_cgroup life than memsw, and might > - * be of interest, even at time of free, when debugging. > - * So share rcu_head with the less interesting memsw. > - */ > - struct rcu_head rcu_freeing; > - /* > - * We also need some space for a worker in deferred freeing. > - * By the time we call it, rcu_freeing is no longer in use. > - */ > - struct work_struct work_freeing; > - }; > + /* > + * the counter to account for mem+swap usage. > + */ > + struct res_counter memsw; > > /* > * the counter to account for kernel memory usage. > @@ -6097,29 +6079,6 @@ static void __mem_cgroup_free(struct mem_cgroup *memcg) > vfree(memcg); > } > > - > -/* > - * Helpers for freeing a kmalloc()ed/vzalloc()ed mem_cgroup by RCU, > - * but in process context. The work_freeing structure is overlaid > - * on the rcu_freeing structure, which itself is overlaid on memsw. > - */ > -static void free_work(struct work_struct *work) > -{ > - struct mem_cgroup *memcg; > - > - memcg = container_of(work, struct mem_cgroup, work_freeing); > - __mem_cgroup_free(memcg); > -} > - > -static void free_rcu(struct rcu_head *rcu_head) > -{ > - struct mem_cgroup *memcg; > - > - memcg = container_of(rcu_head, struct mem_cgroup, rcu_freeing); > - INIT_WORK(&memcg->work_freeing, free_work); > - schedule_work(&memcg->work_freeing); > -} > - > /* > * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled. > */ > @@ -6269,7 +6228,7 @@ static void mem_cgroup_css_free(struct cgroup *cont) > > mem_cgroup_sockets_destroy(memcg); > > - call_rcu(&memcg->rcu_freeing, free_rcu); > + __mem_cgroup_free(memcg); > } > > #ifdef CONFIG_MMU > -- > 1.8.0.2 > -- > To unsubscribe from this list: send the line "unsubscribe cgroups" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/