From mboxrd@z Thu Jan 1 00:00:00 1970 From: Li Zefan Subject: Re: [PATCH] cgroup_freezer: fix freezing groups with stopped tasks Date: Tue, 22 Nov 2011 10:20:02 +0800 Message-ID: <4ECB06D2.6060106@cn.fujitsu.com> References: <1321480234-29241-1-git-send-email-mhocko@suse.cz> <20111121230709.GR25776@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20111121230709.GR25776-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Tejun Heo Cc: containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Michal Hocko , Tomasz Buchert , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Andrew Morton , Paul Menage Tejun Heo wrote: > Hello, Michal. > > On Wed, Nov 16, 2011 at 10:50:34PM +0100, Michal Hocko wrote: >> +/* Task is frozen or will freeze immediately when next it gets woken */ >> +static bool is_task_frozen_enough(struct task_struct *task) >> +{ >> + return frozen(task) || >> + (task_is_stopped_or_traced(task) && freezing(task)); >> +} > > Hmmm... w/ pending freezer updates, the above would always return > %true if there's freezing in progress, which can't be right. Maybe Only if the task is stopped/trace. If we try to freeze a stopped task, it will be kept in freezing state. > just test stopped/traced? > This can trigger a BUG_ON in update_if_frozen(), because we always count a stopped task as frozen. > http://git.kernel.org/?p=linux/kernel/git/tj/misc.git;a=shortlog;h=refs/heads/pm-freezer > > Thanks. > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758170Ab1KVCSZ (ORCPT ); Mon, 21 Nov 2011 21:18:25 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:64301 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1757250Ab1KVCSQ (ORCPT ); Mon, 21 Nov 2011 21:18:16 -0500 Message-ID: <4ECB06D2.6060106@cn.fujitsu.com> Date: Tue, 22 Nov 2011 10:20:02 +0800 From: Li Zefan User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.9) Gecko/20100921 Fedora/3.1.4-1.fc14 Thunderbird/3.1.4 MIME-Version: 1.0 To: Tejun Heo CC: Michal Hocko , linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, containers@lists.linux-foundation.org, Tomasz Buchert , Paul Menage , Andrew Morton Subject: Re: [PATCH] cgroup_freezer: fix freezing groups with stopped tasks References: <1321480234-29241-1-git-send-email-mhocko@suse.cz> <20111121230709.GR25776@google.com> In-Reply-To: <20111121230709.GR25776@google.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2011-11-22 10:17:55, Serialize by Router on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2011-11-22 10:17:57, Serialize complete at 2011-11-22 10:17:57 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Tejun Heo wrote: > Hello, Michal. > > On Wed, Nov 16, 2011 at 10:50:34PM +0100, Michal Hocko wrote: >> +/* Task is frozen or will freeze immediately when next it gets woken */ >> +static bool is_task_frozen_enough(struct task_struct *task) >> +{ >> + return frozen(task) || >> + (task_is_stopped_or_traced(task) && freezing(task)); >> +} > > Hmmm... w/ pending freezer updates, the above would always return > %true if there's freezing in progress, which can't be right. Maybe Only if the task is stopped/trace. If we try to freeze a stopped task, it will be kept in freezing state. > just test stopped/traced? > This can trigger a BUG_ON in update_if_frozen(), because we always count a stopped task as frozen. > http://git.kernel.org/?p=linux/kernel/git/tj/misc.git;a=shortlog;h=refs/heads/pm-freezer > > Thanks. >