From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kamezawa Hiroyuki Subject: Re: [PATCH v4 1/6] memcg: prevent changes to move_charge_at_immigrate during task attach Date: Tue, 29 Jan 2013 09:11:03 +0900 Message-ID: <51071397.2080908@jp.fujitsu.com> References: <1358862461-18046-1-git-send-email-glommer@parallels.com> <1358862461-18046-2-git-send-email-glommer@parallels.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1358862461-18046-2-git-send-email-glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Glauber Costa Cc: cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, Tejun Heo , Michal Hocko , Johannes Weiner (2013/01/22 22:47), Glauber Costa wrote: > Currently, we rely on the cgroup_lock() to prevent changes to > move_charge_at_immigrate during task migration. However, this is only > needed because the current strategy keeps checking this value throughout > the whole process. Since all we need is serialization, one needs only to > guarantee that whatever decision we made in the beginning of a specific > migration is respected throughout the process. > > We can achieve this by just saving it in mc. By doing this, no kind of > locking is needed. > > [ v2: change flag name to avoid confusion ] > > Signed-off-by: Glauber Costa > Acked-by: Michal Hocko Acked-by: KAMEZAWA Hiroyuki