From mboxrd@z Thu Jan 1 00:00:00 1970 From: Qiang Huang Subject: Re: cgroup_fj tests will stick the nort kernel Date: Thu, 25 Apr 2013 16:56:52 +0800 Message-ID: <5178EFD4.9060806@huawei.com> References: <5170F28F.3060002@huawei.com> <51750563.8050301@huawei.com> <1366646447.9609.131.camel@gandalf.local.home> <5176217E.8030008@huawei.com> <5178C922.3060506@huawei.com> <5178ECEE.4070907@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Steven Rostedt , Thomas Gleixner , linux-rt-users , zhangwei To: Li Zefan Return-path: Received: from szxga01-in.huawei.com ([119.145.14.64]:17065 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751786Ab3DYI50 (ORCPT ); Thu, 25 Apr 2013 04:57:26 -0400 In-Reply-To: <5178ECEE.4070907@huawei.com> Sender: linux-rt-users-owner@vger.kernel.org List-ID: On 2013/4/25 16:44, Li Zefan wrote: >> And the patch below, I added your signed-off-by if it looks good to you. > > Don't... > >> Here is the patch seems solve the problem, it looks all good in my box, my >> only concern is how will this affect our RT code. >> >> >> >From 8e4fa4e9a7b510bdaf90b8140ce1e847375abccf Mon Sep 17 00:00:00 2001 >> From: Qiang Huang >> Date: Thu, 25 Apr 2013 10:22:01 +0800 >> Subject: [PATCH] sched: don't clear PF_THREAD_BOUND in select_fallback_rq >> >> This is revert of "sched-clear-pf-thread-bound-on-fallback-rq.patch" >> (commit 0d939066acdcb in v3.4-rt),. >> >> Select_fallback_rq() can be easilly called during system boot, because >> select_task_rq_fair() just return task_cpu(p) for bounded kernel threads, >> which is 0 during system boot and not in tsk_cpus_allowed, so >> select_fallback_rq() is called and PF_THREAD_BOUND is cleared. In my >> box, 1/3 bounded kernel threads will clear that flag after boot. >> >> And it will cause problems, for example: >> # for pid in `ps -e -o pid`; do taskset -p -c 0-15 $pid; done >> this command will cause system hung. >> >> What's more, I don't see why we need to clear this flag any more, >> because "cpu/rt: Rework cpu down for PREEMPT_RT" already remove the >> optimization for PF_THREAD_BOUND on migrate_disable/enable. >> >> Signed-off-by: Qiang Huang >> Signed-off-by: Li Zefan > > You shoudn't have added my SOB... I didn't write this patch and I didn't > even sugguest this fix or check if this is a correct fix. > > Please read Documentation/SubmittingPatches to learn how SOB should > be used. > OK, I'll resend it.