Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752114Ab3J3QAj (ORCPT ); Wed, 30 Oct 2013 12:00:39 -0400 Received: from relay1.mentorg.com ([192.94.38.131]:52904 "EHLO relay1.mentorg.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750754Ab3J3QAi (ORCPT ); Wed, 30 Oct 2013 12:00:38 -0400 Message-ID: <52712D1C.9000802@mentor.com> Date: Wed, 30 Oct 2013 21:00:28 +0500 From: Abbas Raza User-Agent: Mozilla/5.0 (X11; Linux i686; rv:17.0) Gecko/20130330 Thunderbird/17.0.5 MIME-Version: 1.0 To: linux-kernel@vger.kernel.org CC: mingo@redhat.com, peterz@infradead.org, Xie XiuQi Subject: Re: [PATCH] kthread_bind: don't wait in kthread_bind for presmp initcalls References: <1380300451-396-1-git-send-email-abbas_raza@mentor.com> In-Reply-To: <1380300451-396-1-git-send-email-abbas_raza@mentor.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 30 Oct 2013 16:00:34.0393 (UTC) FILETIME=[2AB2F490:01CED589] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1882 Lines: 65 Hi, Any thoughts here please? Thanks . Abbas Raza On 09/27/2013 09:47 PM, Abbas Raza wrote: > From: Abbas Raza > > wait_task_inactive shouldn't be called in __kthread_bind for presmp > initcalls the same way it is done in !SMP case. > > more info here: > http://permalink.gmane.org/gmane.linux.kernel.embedded/4046 > > This patch improves boot time for pre-smp initcalls as given below > > boot time with this patch: > > calling spawn_ksoftirqd+0x0/0x30 @ 1 > initcall spawn_ksoftirqd+0x0/0x30 returned 0 after 0 usecs > > boot time without this patch: > > calling spawn_ksoftirqd+0x0/0x30 @ 1 > initcall spawn_ksoftirqd+0x0/0x30 returned 0 after 19531 usecs > > Signed-off-by: Abbas Raza > --- > kernel/kthread.c | 14 ++++++++++---- > 1 file changed, 10 insertions(+), 4 deletions(-) > > diff --git a/kernel/kthread.c b/kernel/kthread.c > index 760e86d..28b5c4b 100644 > --- a/kernel/kthread.c > +++ b/kernel/kthread.c > @@ -290,11 +290,17 @@ EXPORT_SYMBOL(kthread_create_on_node); > > static void __kthread_bind(struct task_struct *p, unsigned int cpu, long state) > { > - /* Must have done schedule() in kthread() before we set_task_cpu */ > - if (!wait_task_inactive(p, state)) { > - WARN_ON(1); > - return; > + if (!((num_online_cpus() == 1) && !cpu)) { > + /* > + * Must have done schedule() in kthread() before > + * we set_task_cpu > + */ > + if (!wait_task_inactive(p, state)) { > + WARN_ON(1); > + return; > + } > } > + > /* It's safe because the task is inactive. */ > do_set_cpus_allowed(p, cpumask_of(cpu)); > p->flags |= PF_NO_SETAFFINITY; -- 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/