Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761998Ab3DCJct (ORCPT ); Wed, 3 Apr 2013 05:32:49 -0400 Received: from szxga01-in.huawei.com ([119.145.14.64]:50477 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761927Ab3DCJcs (ORCPT ); Wed, 3 Apr 2013 05:32:48 -0400 Message-ID: <515BF737.7070105@huawei.com> Date: Wed, 3 Apr 2013 17:32:39 +0800 From: Li Zefan User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:17.0) Gecko/20130307 Thunderbird/17.0.4 MIME-Version: 1.0 To: Li Zhong CC: , Subject: Re: [PATCH cpuset] Use rebuild_sched_domains() in cpuset_hotplug_workfn() References: <1364886990.5859.12.camel@ThinkPad-T5421.cn.ibm.com> In-Reply-To: <1364886990.5859.12.camel@ThinkPad-T5421.cn.ibm.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.135.68.215] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1888 Lines: 58 On 2013/4/2 15:16, Li Zhong wrote: > In cpuset_hotplug_workfn(), partition_sched_domains() is called without > hotplug lock held, which is actually needed (stated in the function > header of partition_sched_domains()). > > This patch tries to use rebuild_sched_domains() to solve the above > issue, and makes the code looks a little simpler. > I guess you found this just by code inspection, right? The change looks fine and safe at a first glance, but we don't have time to review the patch for now. However I don't know why partition_sched_domains() has to be called with hotplug lock held. After a quick scan, seems the only place in partition_sched_domains() that might need hotplug lock is arch_update_cpu_topology(). It would be better if you had CCed the scheduler guys...They may know the answer. > Signed-off-by: Li Zhong > --- > kernel/cpuset.c | 13 ++----------- > 1 files changed, 2 insertions(+), 11 deletions(-) > > diff --git a/kernel/cpuset.c b/kernel/cpuset.c > index 4f9dfe4..515a713 100644 > --- a/kernel/cpuset.c > +++ b/kernel/cpuset.c > @@ -2222,17 +2222,8 @@ static void cpuset_hotplug_workfn(struct work_struct *work) > flush_workqueue(cpuset_propagate_hotplug_wq); > > /* rebuild sched domains if cpus_allowed has changed */ > - if (cpus_updated) { > - struct sched_domain_attr *attr; > - cpumask_var_t *doms; > - int ndoms; > - > - mutex_lock(&cpuset_mutex); > - ndoms = generate_sched_domains(&doms, &attr); > - mutex_unlock(&cpuset_mutex); > - > - partition_sched_domains(ndoms, doms, attr); > - } > + if (cpus_updated) > + rebuild_sched_domains(); > } > -- 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/