Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933975AbbELWel (ORCPT ); Tue, 12 May 2015 18:34:41 -0400 Received: from ipmail06.adl6.internode.on.net ([150.101.137.145]:8842 "EHLO ipmail06.adl6.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933142AbbELWeh (ORCPT ); Tue, 12 May 2015 18:34:37 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: A2C6CgBbf1JVPPDOLHlcgw+BMoZMrFwBAQEBAQEGmVYCAgEBAoE3TQEBAQEBAQcBAQEBQT+EIAEBAQMBOhwjEAgDGAklDwUlAwcaE4gkB8oyAQEBBwIBHxiFfoUjhDZPB4MXgRYFkBqNHoElg2GHbYYmg1WBBIEFgiMsMYEDI4EgAQEB Date: Wed, 13 May 2015 08:34:07 +1000 From: Dave Chinner To: Len Brown Cc: "Rafael J. Wysocki" , Linux PM list , "linux-kernel@vger.kernel.org" , Len Brown Subject: Re: [PATCH 1/1] suspend: delete sys_sync() Message-ID: <20150512223407.GB4316@dastard> References: <20150511014428.GB15721@dastard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1507 Lines: 39 On Mon, May 11, 2015 at 04:22:26PM -0400, Len Brown wrote: > On Sun, May 10, 2015 at 9:44 PM, Dave Chinner wrote: > > > ...Please explain what your use case is that makes this > > so prohibitively expensive it needs to be removed. > > wake on packet, process packet without turning on the display, > immediately suspend. Do this potentially several times per second. The sync should almost always be a no-op because the filesystems should be clean. In that case, where's the latency coming from? If filesystems were dirtied during the wake period, then we do care that they get sync'd properly before suspend. FWIW, I don't think that s2ram or s2d were designed for this sort of abuse - they really were designed around laptop use cases, which is what I mostly care about... > >> The user-space utilities s2ram and s2disk choose to invoke sync() today. > >> A user can invoke suspend directly via /sys/power/state to skip that cost. > > > > So, you want to have s2disk write all the dirty pages in memory to > > the suspend image, rather than to the filesystem? > > The s2disk utility is unchanged by this proposal, it already includes a sync(). Not everyone uses that utility. Cheers, Dave. -- Dave Chinner david@fromorbit.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/