From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with SMTP id 0168A6008E4 for ; Tue, 3 Aug 2010 02:30:08 -0400 (EDT) Received: from m4.gw.fujitsu.co.jp ([10.0.50.74]) by fgwmail7.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id o736Zc54031400 for (envelope-from kosaki.motohiro@jp.fujitsu.com); Tue, 3 Aug 2010 15:35:38 +0900 Received: from smail (m4 [127.0.0.1]) by outgoing.m4.gw.fujitsu.co.jp (Postfix) with ESMTP id 5F80845DE7A for ; Tue, 3 Aug 2010 15:35:38 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (s4.gw.fujitsu.co.jp [10.0.50.94]) by m4.gw.fujitsu.co.jp (Postfix) with ESMTP id 1773545DE6F for ; Tue, 3 Aug 2010 15:35:38 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id E7D781DB8042 for ; Tue, 3 Aug 2010 15:35:37 +0900 (JST) Received: from m108.s.css.fujitsu.com (m108.s.css.fujitsu.com [10.249.87.108]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 9AFDA1DB803F for ; Tue, 3 Aug 2010 15:35:37 +0900 (JST) From: KOSAKI Motohiro Subject: Re: Bug 12309 - Large I/O operations result in poor interactive performance and high iowait times In-Reply-To: <20100802115748.GA5308@localhost> References: <20100802171954.4F95.A69D9226@jp.fujitsu.com> <20100802115748.GA5308@localhost> Message-Id: <20100803153420.39FD.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Date: Tue, 3 Aug 2010 15:35:35 +0900 (JST) Sender: owner-linux-mm@kvack.org To: Wu Fengguang Cc: kosaki.motohiro@jp.fujitsu.com, Andrew Clayton , Andrew Morton , Mel Gorman , "linux-kernel@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "linux-mm@kvack.org" , Dave Chinner , Chris Mason , Nick Piggin , Rik van Riel , Johannes Weiner , Jens Axboe , Christoph Hellwig , KAMEZAWA Hiroyuki , Andrea Arcangeli , "pvz@pvz.pp.se" , "bgamari@gmail.com" , "larppaxyz@gmail.com" , "seanj@xyke.com" , "kernel-bugs.dev1world@spamgourmet.com" , "akatopaz@gmail.com" , "frankrq2009@gmx.com" , "thomas.pi@arcor.de" , "spawels13@gmail.com" , "vshader@gmail.com" , "rockorequin@hotmail.com" , "ylalym@gmail.com" , "theholyettlz@googlemail.com" , "hassium@yandex.ru" List-ID: > > It mean congestion ignorerance is happend when followings > > (1) the task is kswapd > > (2) the task is flusher thread > > (3) this reclaim is called from zone reclaim (note: I'm thinking this is bug) > > (4) this reclaim is called from __generic_file_aio_write() > > > > (4) is root cause of this latency issue. this behavior was introduced > > by following. > > Yes and no. > > (1)-(4) are good summaries for regular files. However !bdi_write_congested(bdi) > is now unconditionally true for the swapper_space, which means any process can > do swap out to a congested queue and block there. Oops. I missed that. thanks correct me! -- 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/ . Don't email: email@kvack.org