From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH 4/8] cgroup: deactivate CSS's and mark cgroup dead before invoking ->pre_destroy() Date: Wed, 31 Oct 2012 14:27:25 -0700 Message-ID: <20121031212725.GA2945@htj.dyndns.org> References: <1351712650-23709-1-git-send-email-tj@kernel.org> <1351712650-23709-5-git-send-email-tj@kernel.org> <20121031212359.GC5286@dhcp22.suse.cz> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; bh=Dg7P0Vf3Cw94nj+j0Uyq4Vt4aSfK1R/JcL3rvhxg8U0=; b=zYpZQk/N515qb+BIviCcoHKYK6sy+P7Wpg/7uI6HxZb3S9qps7Zv4ovaWMII7wr0gr ubocsd9zQwTg67fh6U/DGgCsBoy/YT7beX8X7vU0WGW15u8wjeDRgnzTsWz4plpNXMCE 2uWgiSiYnt7gbn6vil8ZIDFTxjIR2uSHrDSNrLgFrzkv86D7pHyOPdcH29bGEtXYUfmf ZE6uLrGL5StQRDMBzdyU+cz5aucYudqOGjQ8LYn5SInUJDhZ+Yk/ZEuc42V+xojG91vG Af4HCb7xUfJq7mkgsTQ63KfhAYrvPOouAReSe48np/4o5Qsu9rPOUsxEXGgO/eKkqkdB kTrw== Content-Disposition: inline In-Reply-To: <20121031212359.GC5286-2MMpYkNvuYDjFM9bn6wA6Q@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: Michal Hocko Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Hey, Michal. On Wed, Oct 31, 2012 at 10:23:59PM +0100, Michal Hocko wrote: > > + for_each_subsys(cgrp->root, ss) > > + if (ss->pre_destroy) > > + WARN_ON_ONCE(ss->pre_destroy(cgrp)); > > Do you think that BUG_ON would be too harsh? Yeah, I do think so. In general, I think the consensus now is to prefer WARN_ON[_ONCE]() over BUG_ON() whenever possible. It's not like we can get more information from BUG_ON()s (more likely to get less reporting actually by taking down the machine). Limping machines are better than dead ones and there just isn't much to gain here by killing it. Thanks. -- tejun From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965754Ab2JaV1c (ORCPT ); Wed, 31 Oct 2012 17:27:32 -0400 Received: from mail-da0-f46.google.com ([209.85.210.46]:65404 "EHLO mail-da0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933899Ab2JaV1a (ORCPT ); Wed, 31 Oct 2012 17:27:30 -0400 Date: Wed, 31 Oct 2012 14:27:25 -0700 From: Tejun Heo To: Michal Hocko Cc: lizefan@huawei.com, hannes@cmpxchg.org, bsingharora@gmail.com, kamezawa.hiroyu@jp.fujitsu.com, containers@lists.linux-foundation.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Glauber Costa Subject: Re: [PATCH 4/8] cgroup: deactivate CSS's and mark cgroup dead before invoking ->pre_destroy() Message-ID: <20121031212725.GA2945@htj.dyndns.org> References: <1351712650-23709-1-git-send-email-tj@kernel.org> <1351712650-23709-5-git-send-email-tj@kernel.org> <20121031212359.GC5286@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20121031212359.GC5286@dhcp22.suse.cz> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hey, Michal. On Wed, Oct 31, 2012 at 10:23:59PM +0100, Michal Hocko wrote: > > + for_each_subsys(cgrp->root, ss) > > + if (ss->pre_destroy) > > + WARN_ON_ONCE(ss->pre_destroy(cgrp)); > > Do you think that BUG_ON would be too harsh? Yeah, I do think so. In general, I think the consensus now is to prefer WARN_ON[_ONCE]() over BUG_ON() whenever possible. It's not like we can get more information from BUG_ON()s (more likely to get less reporting actually by taking down the machine). Limping machines are better than dead ones and there just isn't much to gain here by killing it. Thanks. -- tejun