From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx157.postini.com [74.125.245.157]) by kanga.kvack.org (Postfix) with SMTP id C5B036B007B for ; Thu, 28 Jun 2012 12:06:27 -0400 (EDT) Received: by lbjn8 with SMTP id n8so4221184lbj.14 for ; Thu, 28 Jun 2012 09:06:25 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <4FEC16EF.40408@jp.fujitsu.com> References: <4FACDED0.3020400@jp.fujitsu.com> <20120621202043.GD4642@google.com> <4FE3ADDD.9060908@jp.fujitsu.com> <20120627175818.GM15811@google.com> <4FEC16EF.40408@jp.fujitsu.com> Date: Thu, 28 Jun 2012 09:06:25 -0700 Message-ID: Subject: Re: [PATCH v3][0/6] memcg: prevent -ENOMEM in pre_destroy() From: Tejun Heo Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Kamezawa Hiroyuki Cc: "linux-mm@kvack.org" , "cgroups@vger.kernel.org" , Michal Hocko , Johannes Weiner , Frederic Weisbecker , Han Ying , Glauber Costa , "Aneesh Kumar K.V" , Andrew Morton , Hiroyuki Kamezawa , Linux Kernel Hello, KAME. On Thu, Jun 28, 2012 at 1:33 AM, Kamezawa Hiroyuki wrote: >> Ooh, once memcg drops the __DEPRECATED_clear_css_refs, cgroup_rmdir() >> will mark the cgroup dead before start calling pre_destroy() and none >> of the above will happen. >> > > Hm, threads which touches memcg should hold memcg's reference count rather > than css. > Right ? IIUC, one of reason is a reference from kswapd etc...hm. I'll check > it. Not sure I'm following. I meant that css_tryget() will always fail once pre_destroy() calls being for the cgroup, so no new child or reference can be created for it after that point. Thanks. -- tejun -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org