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 BBC4B6B006A for ; Fri, 8 Oct 2010 05:25:28 -0400 (EDT) Date: Fri, 8 Oct 2010 11:25:20 +0200 From: Christoph Hellwig Subject: Re: [PATCH] bdi: use deferable timer for sync_supers task Message-ID: <20101008092520.GB5426@lst.de> References: <20101008083514.GA12402@ywang-moblin2.bj.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20101008083514.GA12402@ywang-moblin2.bj.intel.com> Sender: owner-linux-mm@kvack.org To: Yong Wang Cc: Jens Axboe , Christoph Hellwig , Artem Bityutskiy , Wu Fengguang , linux-kernel@vger.kernel.org, linux-mm@kvack.org, xia.wu@intel.com List-ID: 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. -- 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