Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758601Ab1EZXsf (ORCPT ); Thu, 26 May 2011 19:48:35 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:48491 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756405Ab1EZXse (ORCPT ); Thu, 26 May 2011 19:48:34 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 Date: Fri, 27 May 2011 08:41:39 +0900 From: KAMEZAWA Hiroyuki To: Tejun Heo Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "akpm@linux-foundation.org" , Ying Han , "nishimura@mxp.nes.nec.co.jp" , "balbir@linux.vnet.ibm.com" Subject: Re: [RFC][PATCH v3 7/10] workqueue: add WQ_IDLEPRI Message-Id: <20110527084139.d334819f.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20110526114406.GG9715@htj.dyndns.org> References: <20110526141047.dc828124.kamezawa.hiroyu@jp.fujitsu.com> <20110526143024.7f66e797.kamezawa.hiroyu@jp.fujitsu.com> <20110526093808.GE9715@htj.dyndns.org> <20110526193018.12b3ddea.kamezawa.hiroyu@jp.fujitsu.com> <20110526195019.8af6d882.kamezawa.hiroyu@jp.fujitsu.com> <20110526114406.GG9715@htj.dyndns.org> Organization: FUJITSU Co. LTD. X-Mailer: Sylpheed 3.1.0 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2062 Lines: 67 On Thu, 26 May 2011 13:44:06 +0200 Tejun Heo wrote: > Hello, > > On Thu, May 26, 2011 at 07:50:19PM +0900, KAMEZAWA Hiroyuki wrote: > > On Thu, 26 May 2011 19:30:18 +0900 > > KAMEZAWA Hiroyuki wrote: > > > In the next version, I'll try some like.. > > > == > > > process_one_work(...) { > > > ..... > > > spin_unlock_irq(&gcwq->lock); > > > ..... > > > if (cwq->wq->flags & WQ_IDLEPRI) { > > > set_scheduler(...SCHED_IDLE...) > > > cond_resched(); > > > scheduler_switched = true; > > > } > > > f(work) > > > if (scheduler_switched) > > > set_scheduler(...SCHED_OTHER...) > > > spin_lock_irq(&gcwq->lock); > > > } > > > == > > > Patch size will be much smaller. (Should I do this in memcg's code ??) > > > > > > > BTW, my concern is that if f(work) is enough short,effect of SCHED_IDLE will never > > be found because SCHED_OTHER -> SCHED_IDLE -> SCHED_OTHER switch is very fast. > > Changed "weight" of CFQ never affects the next calculation of vruntime..of the > > thread and the work will show the same behavior with SCHED_OTHER. > > > > I'm sorry if I misunderstand CFQ and setscheduler(). > > Hmm... I'm not too familiar there either but, > > * If prio is lowered (you're gonna lower it too, right?), > prio_changed_fair() is called which in turn does resched_task() as > necessary. > > * More importantly, for short work items, it's likely to not matter at > all. If you can determine beforehand that it's not gonna take very > long time, queueing on system_wq would be more efficient. > > Thanks. > Ok, Now, I use following style. (short work)->requeue->(short work)->requeue I'll change this as (set SCHED_IDLE)->long work (until the end)->(set SCHED_OTHER) Then, I'll see what I want. Thanks. -Kame -- 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/