Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751980AbaLCSCp (ORCPT ); Wed, 3 Dec 2014 13:02:45 -0500 Received: from mail-qa0-f48.google.com ([209.85.216.48]:48414 "EHLO mail-qa0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751124AbaLCSCo (ORCPT ); Wed, 3 Dec 2014 13:02:44 -0500 Date: Wed, 3 Dec 2014 13:02:41 -0500 From: Tejun Heo To: NeilBrown Cc: Jan Kara , Lai Jiangshan , Dongsu Park , linux-kernel@vger.kernel.org Subject: Re: [PATCH - v3?] workqueue: allow rescuer thread to do more work. Message-ID: <20141203180241.GD5013@htj.dyndns.org> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20141203172010.GC5013@htj.dyndns.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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); + spin_unlock(&wq_mayday_lock); + } + } /* * Put the reference grabbed by send_mayday(). @pool won't -- tejun -- 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/