From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752827AbaLDA6M (ORCPT ); Wed, 3 Dec 2014 19:58:12 -0500 Received: from cn.fujitsu.com ([59.151.112.132]:30317 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1752558AbaLDA6K (ORCPT ); Wed, 3 Dec 2014 19:58:10 -0500 X-IronPort-AV: E=Sophos;i="5.04,848,1406563200"; d="scan'208";a="44468458" Message-ID: <547FB27E.5030904@cn.fujitsu.com> Date: Thu, 4 Dec 2014 09:01:50 +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 - v3?] workqueue: allow rescuer thread to do more work. References: <20141104142240.GD14459@htj.dyndns.org> <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> In-Reply-To: <20141203180241.GD5013@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 02:02 AM, Tejun Heo wrote: > So, something like the following. Only compile tested. I'll test it > and post proper patches w/ due credits. > > Thanks. > > Index: work/kernel/workqueue.c > =================================================================== > --- work.orig/kernel/workqueue.c > +++ work/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); > } > @@ -2248,12 +2248,29 @@ repeat: > * Slurp in all works issued via this workqueue and > * process'em. > */ > - WARN_ON_ONCE(!list_empty(&rescuer->scheduled)); > + WARN_ON_ONCE(!list_empty(scheduled)); > list_for_each_entry_safe(work, n, &pool->worklist, entry) > if (get_work_pwq(work) == pwq) > move_linked_works(work, scheduled, &n); > > - process_scheduled_works(rescuer); > + if (!list_empty(scheduled)) { > + process_scheduled_works(rescuer); > + > + /* > + * The above execution of rescued work items could > + * have created more to rescue through > + * pwq_activate_first_delayed() or chained > + * queueing. Let's put @pwq back on mayday list so > + * that such back-to-back work items, which may be > + * being used to relieve memory pressure, don't > + * incur MAYDAY_INTERVAL delay inbetween. > + */ > + if (need_to_create_worker(pool)) { > + spin_lock(&wq_mayday_lock); > + list_move_tail(&pwq->mayday_node, &wq->maydays); how about the pwq is empty now? and ... > + spin_unlock(&wq_mayday_lock); > + } > + } > > /* > * Put the reference grabbed by send_mayday(). @pool won't and the pwq is scheduled free here> >