Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762943AbZAPEci (ORCPT ); Thu, 15 Jan 2009 23:32:38 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755413AbZAPEc2 (ORCPT ); Thu, 15 Jan 2009 23:32:28 -0500 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:54742 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755098AbZAPEc1 (ORCPT ); Thu, 15 Jan 2009 23:32:27 -0500 Date: Fri, 16 Jan 2009 13:31:21 +0900 From: KAMEZAWA Hiroyuki To: Daisuke Nishimura Cc: "Andrew Morton" , "LKML" , "linux-mm" , "Balbir Singh" , "Pavel Emelyanov" , "Li Zefan" , "Paul Menage" Subject: Re: [BUGFIX][PATCH] memcg: get/put parents at create/free Message-Id: <20090116133121.2f50d71d.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20090116132253.69cf80ea.nishimura@mxp.nes.nec.co.jp> References: <20090113184533.6ffd2af9.nishimura@mxp.nes.nec.co.jp> <20090114175121.275ecd59.nishimura@mxp.nes.nec.co.jp> <7602a77a9fc6b1e8757468048fde749a.squirrel@webmail-b.css.fujitsu.com> <20090115100330.37d89d3d.nishimura@mxp.nes.nec.co.jp> <20090115110044.3a863af8.kamezawa.hiroyu@jp.fujitsu.com> <20090115111420.8559bdb3.nishimura@mxp.nes.nec.co.jp> <20090115133814.a52460fa.nishimura@mxp.nes.nec.co.jp> <20090115164537.d402e95f.nishimura@mxp.nes.nec.co.jp> <20090115165453.271848d9.kamezawa.hiroyu@jp.fujitsu.com> <20090115171315.965da4e3.nishimura@mxp.nes.nec.co.jp> <20090115172336.0ed780bb.kamezawa.hiroyu@jp.fujitsu.com> <20090115175131.9542ae59.nishimura@mxp.nes.nec.co.jp> <20090115181056.74a938d5.kamezawa.hiroyu@jp.fujitsu.com> <20090116105009.7cabac46.nishimura@mxp.nes.nec.co.jp> <20090116132253.69cf80ea.nishimura@mxp.nes.nec.co.jp> Organization: FUJITSU Co. LTD. X-Mailer: Sylpheed 2.5.0 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3027 Lines: 89 On Fri, 16 Jan 2009 13:22:53 +0900 Daisuke Nishimura wrote: > This is a fix for memcg-get-put-parents-at-create-free.patch. > Thank you, I'll test. Reviewed-by: KAMEZAWA Hiroyuki > === > From: Daisuke Nishimura > > Andrew suggested that it's strange to add a little helper function for get(), > while put() is open-code. > > This patch also adds a few comments. > > Signed-off-by: Daisuke Nishimura > --- > mm/memcontrol.c | 20 ++++++++++---------- > 1 files changed, 10 insertions(+), 10 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 45e1b51..92790e4 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -203,7 +203,6 @@ pcg_default_flags[NR_CHARGE_TYPE] = { > static void mem_cgroup_get(struct mem_cgroup *mem); > static void mem_cgroup_put(struct mem_cgroup *mem); > static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem); > -static void mem_cgroup_get_parent(struct mem_cgroup *mem); > > static void mem_cgroup_charge_statistics(struct mem_cgroup *mem, > struct page_cgroup *pc, > @@ -2195,6 +2194,9 @@ static void mem_cgroup_put(struct mem_cgroup *mem) > } > } > > +/* > + * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled. > + */ > static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem) > { > if (!mem->res.parent) > @@ -2202,14 +2204,6 @@ static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem) > return mem_cgroup_from_res_counter(mem->res.parent, res); > } > > -static void mem_cgroup_get_parent(struct mem_cgroup *mem) > -{ > - struct mem_cgroup *parent = parent_mem_cgroup(mem); > - > - if (parent) > - mem_cgroup_get(parent); > -} > - > #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP > static void __init enable_swap_cgroup(void) > { > @@ -2247,6 +2241,13 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) > if (parent && parent->use_hierarchy) { > res_counter_init(&mem->res, &parent->res); > res_counter_init(&mem->memsw, &parent->memsw); > + /* > + * We increment refcnt of the parent to ensure that we can > + * safely access it on res_counter_charge/uncharge. > + * This refcnt will be decremented when freeing this > + * mem_cgroup(see mem_cgroup_put). > + */ > + mem_cgroup_get(parent); > } else { > res_counter_init(&mem->res, NULL); > res_counter_init(&mem->memsw, NULL); > @@ -2257,7 +2258,6 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) > if (parent) > mem->swappiness = get_swappiness(parent); > atomic_set(&mem->refcnt, 1); > - mem_cgroup_get_parent(mem); > return &mem->css; > free_out: > __mem_cgroup_free(mem); > -- 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/