From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932786Ab0E1K62 (ORCPT ); Fri, 28 May 2010 06:58:28 -0400 Received: from casper.infradead.org ([85.118.1.10]:45474 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932589Ab0E1K6X (ORCPT ); Fri, 28 May 2010 06:58:23 -0400 Subject: Re: [linux-pm] [PATCH 0/8] Suspend block api (version 8) From: Peter Zijlstra To: Alan Cox Cc: "Rafael J. Wysocki" , Matthew Garrett , Alan Stern , Thomas Gleixner , Paul@smtp1.linux-foundation.org, LKML , Florian Mickler , Linux OMAP Mailing List , Linux PM In-Reply-To: <20100528005045.6ea5feba@lxorguk.ukuu.org.uk> References: <20100527181433.GG3543@srcf.ucam.org> <20100527200313.5c532f2f@lxorguk.ukuu.org.uk> <201005280110.17075.rjw@sisk.pl> <20100528005045.6ea5feba@lxorguk.ukuu.org.uk> Content-Type: text/plain; charset="UTF-8" Date: Fri, 28 May 2010 09:29:57 +0200 Message-ID: <1275031797.32462.18.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2010-05-28 at 00:50 +0100, Alan Cox wrote: > Today "idle" means "no task running" > > If you are prepared to rephrase that as "no task that matters is running" > what would need to answer ? I'm not sure we need or want to go there. Why not simply let upatedb block on its IO because its QoS policy tells us that its IO priority is idle. Therefore it will not avoid the IO device from going idle and indefinitely delaying servicing requests. When updatedb blocks, the runqueue becomes empty and we gain goodness. Or are we talking about the same thing?