From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932430AbaLDO53 (ORCPT ); Thu, 4 Dec 2014 09:57:29 -0500 Received: from mail-qc0-f176.google.com ([209.85.216.176]:63725 "EHLO mail-qc0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932128AbaLDO51 (ORCPT ); Thu, 4 Dec 2014 09:57:27 -0500 Date: Thu, 4 Dec 2014 09:57:22 -0500 From: Tejun Heo To: Lai Jiangshan Cc: NeilBrown , Jan Kara , Dongsu Park , linux-kernel@vger.kernel.org Subject: Re: [PATCH - v3?] workqueue: allow rescuer thread to do more work. Message-ID: <20141204145722.GC15219@htj.dyndns.org> References: <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> <547FB27E.5030904@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <547FB27E.5030904@cn.fujitsu.com> 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 On Thu, Dec 04, 2014 at 09:01:50AM +0800, Lai Jiangshan wrote: > > + 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 ... It will be taken off list the next round. It's silly to scan the list again here. The only thing that'd do is adding more code and adding an extra scan when the pwq actually needs to be requeued. > > + spin_unlock(&wq_mayday_lock); > > + } > > + } > > > > /* > > * Put the reference grabbed by send_mayday(). @pool won't > > and the pwq is scheduled free here> Added get_pwq() before list_move_tail() as Dongsu suggested. Thanks. -- tejun