From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with ESMTP id 60B8F6B006A for ; Fri, 8 Oct 2010 06:05:32 -0400 (EDT) Subject: Re: [PATCH] bdi: use deferable timer for sync_supers task From: Artem Bityutskiy Reply-To: Artem.Bityutskiy@nokia.com In-Reply-To: <20101008092520.GB5426@lst.de> References: <20101008083514.GA12402@ywang-moblin2.bj.intel.com> <20101008092520.GB5426@lst.de> Content-Type: text/plain; charset="UTF-8" Date: Fri, 08 Oct 2010 13:02:35 +0300 Message-ID: <1286532155.2095.52.camel@localhost> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org To: ext Christoph Hellwig Cc: Yong Wang , Jens Axboe , Wu Fengguang , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "xia.wu@intel.com" List-ID: On Fri, 2010-10-08 at 11:25 +0200, ext Christoph Hellwig wrote: > On Fri, Oct 08, 2010 at 04:35:14PM +0800, Yong Wang wrote: > > sync_supers task currently wakes up periodically for superblock > > writeback. This hurts power on battery driven devices. This patch > > turns this housekeeping timer into a deferable timer so that it > > does not fire when system is really idle. > > How long can the timer be defereed? We can't simply stop writing > out data for a long time. I think the current timer value should be > the upper bound, but allowing to fire earlier to run during the > same wakeup cycle as others is fine. Infinitely. There are range hrtimers which can do exactly what you said - you specify the hard and soft limits there. -- Best Regards, Artem Bityutskiy (D?N?N?N?D 1/4 D?D,N?N?N?DoD,D1) -- 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