From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx177.postini.com [74.125.245.177]) by kanga.kvack.org (Postfix) with SMTP id 28A566B004A for ; Wed, 15 Feb 2012 19:02:03 -0500 (EST) Received: from m1.gw.fujitsu.co.jp (unknown [10.0.50.71]) by fgwmail5.fujitsu.co.jp (Postfix) with ESMTP id 376593EE0BD for ; Thu, 16 Feb 2012 09:02:01 +0900 (JST) Received: from smail (m1 [127.0.0.1]) by outgoing.m1.gw.fujitsu.co.jp (Postfix) with ESMTP id 20E4245DE59 for ; Thu, 16 Feb 2012 09:02:01 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (s1.gw.fujitsu.co.jp [10.0.50.91]) by m1.gw.fujitsu.co.jp (Postfix) with ESMTP id F17C745DE55 for ; Thu, 16 Feb 2012 09:02:00 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id E5475E08002 for ; Thu, 16 Feb 2012 09:02:00 +0900 (JST) Received: from m105.s.css.fujitsu.com (m105.s.css.fujitsu.com [10.240.81.145]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id 9F80F1DB803F for ; Thu, 16 Feb 2012 09:02:00 +0900 (JST) Date: Thu, 16 Feb 2012 09:00:37 +0900 From: KAMEZAWA Hiroyuki Subject: Re: reclaim the LRU lists full of dirty/writeback pages Message-Id: <20120216090037.31d04ec7.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20120214131812.GA17625@localhost> References: <20120208093120.GA18993@localhost> <20120210114706.GA4704@localhost> <20120211124445.GA10826@localhost> <20120214101931.GB5938@suse.de> <20120214131812.GA17625@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Wu Fengguang Cc: Mel Gorman , Greg Thelen , Jan Kara , "bsingharora@gmail.com" , Hugh Dickins , Michal Hocko , linux-mm@kvack.org, Ying Han , "hannes@cmpxchg.org" , Rik van Riel , Minchan Kim On Tue, 14 Feb 2012 21:18:12 +0800 Wu Fengguang wrote: > > --- linux.orig/include/linux/backing-dev.h 2012-02-14 19:43:06.000000000 +0800 > +++ linux/include/linux/backing-dev.h 2012-02-14 19:49:26.000000000 +0800 > @@ -304,6 +304,8 @@ void clear_bdi_congested(struct backing_ > void set_bdi_congested(struct backing_dev_info *bdi, int sync); > long congestion_wait(int sync, long timeout); > long wait_iff_congested(struct zone *zone, int sync, long timeout); > +long reclaim_wait(long timeout); > +void reclaim_rotated(void); > > static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi) > { > --- linux.orig/mm/backing-dev.c 2012-02-14 19:26:15.000000000 +0800 > +++ linux/mm/backing-dev.c 2012-02-14 20:09:45.000000000 +0800 > @@ -873,3 +873,38 @@ out: > return ret; > } > EXPORT_SYMBOL(wait_iff_congested); > + > +static DECLARE_WAIT_QUEUE_HEAD(reclaim_wqh); > + > +/** > + * reclaim_wait - wait for some pages being rotated to the LRU tail > + * @timeout: timeout in jiffies > + * > + * Wait until @timeout, or when some (typically PG_reclaim under writeback) > + * pages rotated to the LRU so that page reclaim can make progress. > + */ > +long reclaim_wait(long timeout) > +{ > + long ret; > + unsigned long start = jiffies; > + DEFINE_WAIT(wait); > + > + prepare_to_wait(&reclaim_wqh, &wait, TASK_KILLABLE); > + ret = io_schedule_timeout(timeout); > + finish_wait(&reclaim_wqh, &wait); > + > + trace_writeback_reclaim_wait(jiffies_to_usecs(timeout), > + jiffies_to_usecs(jiffies - start)); > + > + return ret; > +} > +EXPORT_SYMBOL(reclaim_wait); > + > +void reclaim_rotated() > +{ > + wait_queue_head_t *wqh = &reclaim_wqh; > + > + if (waitqueue_active(wqh)) > + wake_up(wqh); > +} > + Thank you. I like this approach. A nitpick is that this may wake up all waiters in the system when a memcg is rotated. How about wait_event() + condition by bitmap (using per memcg unique IDs.) ? Thanks, -Kame -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org