Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753255AbbEKGdQ (ORCPT ); Mon, 11 May 2015 02:33:16 -0400 Received: from mail-vn0-f54.google.com ([209.85.216.54]:36629 "EHLO mail-vn0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752565AbbEKGdM (ORCPT ); Mon, 11 May 2015 02:33:12 -0400 MIME-Version: 1.0 In-Reply-To: <20150508152513.GB28439@htj.duckdns.org> References: <20150507064557.GA26928@july> <20150507154212.GA12245@htj.duckdns.org> <20150508152513.GB28439@htj.duckdns.org> Date: Mon, 11 May 2015 15:33:10 +0900 X-Google-Sender-Auth: dGcIDDoT4SLWNfpOLDCdSnakTOo Message-ID: Subject: Re: [RFC PATCH] PM, freezer: Don't thaw when it's intended frozen processes From: Krzysztof Kozlowski To: Tejun Heo Cc: Kyungmin Park , linux-mm , Andrew Morton , "\\Rafael J. Wysocki\\" , David Rientjes , Johannes Weiner , Oleg Nesterov , Cong Wang , LKML , Linux PM list Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2022 Lines: 55 2015-05-09 0:25 GMT+09:00 Tejun Heo : > Hello, Kyungmin. > > On Fri, May 08, 2015 at 09:04:26AM +0900, Kyungmin Park wrote: >> > I need to think more about it but as an *optimization* we can add >> > freezing() test before actually waking tasks up during resume, but can >> > you please clarify what you're seeing? >> >> The mobile application has life cycle and one of them is 'suspend' >> state. it's different from 'pause' or 'background'. >> if there are some application and enter go 'suspend' state. all >> behaviors are stopped and can't do anything. right it's suspended. but >> after system suspend & resume, these application is thawed and >> running. even though system know it's suspended. >> >> We made some test application, print out some message within infinite >> loop. when it goes 'suspend' state. nothing is print out. but after >> system suspend & resume, it prints out again. that's not desired >> behavior. and want to address it. >> >> frozen user processes should be remained as frozen while system >> suspend & resume. > > Yes, they should and I'm not sure why what you're saying is happening > because freezing() test done from the frozen tasks themselves should > keep them in the freezer. Which kernel version did you test? Can you > please verify it against a recent kernel? Hi, I tested it on v4.1-rc3 and next-20150508. Task was moved to frozen cgroup: ----- root@localhost:/sys/fs/cgroup/freezer/frozen# grep . * cgroup.clone_children:0 cgroup.procs:2750 freezer.parent_freezing:0 freezer.self_freezing:1 freezer.state:FROZEN notify_on_release:0 tasks:2750 tasks:2773 ----- Unfortunately during system resume the process was woken up. The "if (frozen(p))" check was true. Is it expected behaviour? Best regards, Krzysztof -- 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/