Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933516AbaLECFm (ORCPT ); Thu, 4 Dec 2014 21:05:42 -0500 Received: from cn.fujitsu.com ([59.151.112.132]:16226 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751838AbaLECFl (ORCPT ); Thu, 4 Dec 2014 21:05:41 -0500 X-IronPort-AV: E=Sophos;i="5.04,848,1406563200"; d="scan'208";a="44534212" Message-ID: <548113DC.9040409@cn.fujitsu.com> Date: Fri, 5 Dec 2014 10:09:32 +0800 From: Lai Jiangshan User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.9) Gecko/20100921 Fedora/3.1.4-1.fc14 Thunderbird/3.1.4 MIME-Version: 1.0 To: Tejun Heo CC: NeilBrown , Jan Kara , Dongsu Park , Subject: Re: [PATCH workqueue/for-3.18-fixes 1/2] workqueue: invert the order between pool->lock and wq_mayday_lock References: <20141106165811.GA2338@gmail.com> <545C368C.5040704@cn.fujitsu.com> <20141110162848.6f2246bb@notabene.brown> <20141110085250.GB15948@quack.suse.cz> <20141111090402.35fa0700@notabene.brown> <20141118152754.60b0c75e@notabene.brown> <20141202204304.GR10918@htj.dyndns.org> <20141203114011.5d02dc43@notabene.brown> <20141203172010.GC5013@htj.dyndns.org> <20141203180241.GD5013@htj.dyndns.org> <20141204151104.GD15219@htj.dyndns.org> In-Reply-To: <20141204151104.GD15219@htj.dyndns.org> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.167.226.103] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/04/2014 11:11 PM, Tejun Heo wrote: > Currently, pool->lock nests inside pool->lock. There's no inherent > reason for this order. The only place where the two locks are held > together is pool_mayday_timeout() and it just got decided that way. > > This nesting order turns out to complicate things with the planned > rescuer_thread() update. Let's invert them. This doesn't cause any > behavior differences. > > Signed-off-by: Tejun Heo > Cc: NeilBrown > Cc: Dongsu Park > Cc: Lai Jiangshan Reviewed-by: Lai Jiangshan > --- > kernel/workqueue.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > --- a/kernel/workqueue.c > +++ b/kernel/workqueue.c > @@ -1804,8 +1804,8 @@ static void pool_mayday_timeout(unsigned > struct worker_pool *pool = (void *)__pool; > struct work_struct *work; > > - spin_lock_irq(&wq_mayday_lock); /* for wq->maydays */ > - spin_lock(&pool->lock); > + spin_lock_irq(&pool->lock); > + spin_lock(&wq_mayday_lock); /* for wq->maydays */ > > if (need_to_create_worker(pool)) { > /* > @@ -1818,8 +1818,8 @@ static void pool_mayday_timeout(unsigned > send_mayday(work); > } > > - spin_unlock(&pool->lock); > - spin_unlock_irq(&wq_mayday_lock); > + spin_unlock(&wq_mayday_lock); > + spin_unlock_irq(&pool->lock); > > mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INTERVAL); > } > -- 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/