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 88D836B008A for ; Fri, 8 Oct 2010 06:47:25 -0400 (EDT) Date: Fri, 8 Oct 2010 18:27:09 +0800 From: Yong Wang Subject: Re: [PATCH] bdi: use deferable timer for sync_supers task Message-ID: <20101008102709.GA12682@ywang-moblin2.bj.intel.com> References: <20101008083514.GA12402@ywang-moblin2.bj.intel.com> <20101008092520.GB5426@lst.de> <1286532586.2095.55.camel@localhost> <1286533687.2095.58.camel@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1286533687.2095.58.camel@localhost> Sender: owner-linux-mm@kvack.org To: Artem Bityutskiy Cc: "Wu, Xia" , Christoph Hellwig , Jens Axboe , "Wu, Fengguang" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" List-ID: On Fri, Oct 08, 2010 at 01:28:07PM +0300, Artem Bityutskiy wrote: > On Fri, 2010-10-08 at 18:27 +0800, Wu, Xia wrote: > > > However, when the next wake-up interrupt happens is not defined. It can > > > happen 1ms after, or 1 minute after, or 1 hour after. What Christoph > > > says is that there should be some guarantee that sb writeout starts, > > > say, within 5 to 10 seconds interval. Deferrable timers do not guarantee > > > this. But take a look at the range hrtimers - they do exactly this. > > > > If the system is in sleep state, is there any data which should be written? > > May be yes, may be no. > Thanks for the quick response, Artem. May I know what might need to be written out when system is really idle? -Yong -- 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