From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751584Ab0EaX0K (ORCPT ); Mon, 31 May 2010 19:26:10 -0400 Received: from mail-px0-f174.google.com ([209.85.212.174]:41002 "EHLO mail-px0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750930Ab0EaX0I (ORCPT ); Mon, 31 May 2010 19:26:08 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:reply-to:references:mime-version :content-type:content-disposition:content-transfer-encoding :in-reply-to:user-agent; b=ELed4xYxfA73YLhoj0uSEKw17sPhyBKkzNmwaIfBLJIBVzYuMTyZqBAi1j2mGBLHvt yqmcxMywG7zrRugG1FiC1R0sSaL+ZvTc86xuL77LtQlbT6824btdIUX6GyUhs9Yx6eM6 9P/wBf7FZitYMntF/kkURKDMeVWXHPuw0DiYU= Date: Mon, 31 May 2010 16:26:17 -0700 From: mark gross <640e9920@gmail.com> To: "Rafael J. Wysocki" Cc: Arve =?iso-8859-1?B?SGr4bm5lduVn?= , Alan Stern , Florian Mickler , Peter Zijlstra , Linux PM , Brian Swetland , Alan Cox , Matthew Garrett , Thomas Gleixner , LKML , Ingo Molnar , markgross@thegnar.org Subject: Re: [linux-pm] [PATCH 0/8] Suspend block api (version 8) Message-ID: <20100531232617.GF31155@gvim.org> Reply-To: markgross@thegnar.org References: <201005312338.55109.rjw@sisk.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <201005312338.55109.rjw@sisk.pl> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 31, 2010 at 11:38:55PM +0200, Rafael J. Wysocki wrote: > On Monday 31 May 2010, Arve Hjønnevåg wrote: > > 2010/5/29 Alan Stern : > > > On Sat, 29 May 2010, Arve Hjønnevåg wrote: > > > > > >> > In place of in-kernel suspend blockers, there will be a new type of QoS > > >> > constraint -- call it QOS_EVENTUALLY. It's a very weak constraint, > > >> > compatible with all cpuidle modes in which runnable threads are allowed > > >> > to run (which is all of them), but not compatible with suspend. > > >> > > > >> This sound just like another API rename. It will work, but given that > > >> suspend blockers was the name least objectionable last time around, > > >> I'm not sure what this would solve. > > > > > > It's not just a rename. By changing this into a QoS constraint, we > > > make it more generally useful. Instead of standing on its own, it > > > becomes part of the PM-QOS framework. > > > > > > > We cannot use the existing pm-qos framework. It is not safe to call > > from atomic context. > > We've just merged a patch that fixed that if I'm not mistaken. Mark, did your > PM QoS update fix that? > I'm pretty sure it can be called in atomic context, and if its not I'm sure we can fix that. It can be called in atomic context. I don't think it was ever a problem to call it in atomic context. The problem it had was that crappy list of string compares. Thats been fixed. --mgross > > Also, it does not have any state constraints, so it iterates over every > > registered constraint each time one of them changes. > > That's fixable IMO. > > > Nor does is currently provide any stats for debugging. > > That's why Alan is proposing to add that. > > > The original wakelock patchset supported a wakelock type so it could > > be used to block more then suspend, but I had to remove this because > > it "overlapped" with pm-qos. So, yes I do consider this just another > > rename. > > It's an extension of an existing framework rather than an addition of a new > one, with entirely new API and so on. Extending existing APIs is much > preferred to adding new ones, in general. > > Rafael