From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with SMTP id 73DD3600429 for ; Mon, 2 Aug 2010 20:42:16 -0400 (EDT) Date: Tue, 3 Aug 2010 08:45:11 +0800 From: Wu Fengguang Subject: Re: Bug 12309 - Large I/O operations result in poor interactive performance and high iowait times Message-ID: <20100803004511.GB5198@localhost> References: <20100802003616.5b31ed8b@digital-domain.net> <20100802081253.GA27492@localhost> <20100802171954.4F95.A69D9226@jp.fujitsu.com> <20100802115748.GA5308@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Sender: owner-linux-mm@kvack.org To: Minchan Kim Cc: KOSAKI Motohiro , 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: > > What in my mind is (without any throttling) > > > > A A A A if (PageSwapcache(page)) { > > A A A A A A A A if (bdi_write_congested(bdi)) > > You mentioned following as. > > "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." > > But you used bdi_write_congested in here. > Which is right? Ah sorry, I was also cheated by the name.. bdi_write_congested() won't work for swap_backing_dev_info. Anyway you may take it as "pseudo" code :) Thanks, Fengguang -- 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