From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756593Ab0FANqo (ORCPT ); Tue, 1 Jun 2010 09:46:44 -0400 Received: from mail-pw0-f46.google.com ([209.85.160.46]:45803 "EHLO mail-pw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756093Ab0FANqn (ORCPT ); Tue, 1 Jun 2010 09:46:43 -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=QhqIItkCAreG0d17QvcuR9DXkTS8HKQItvGK8Ljer9njP07JDjtL4ZfD0WOgfgGQ6c pdhupa0S/0mGGpYZMukZELOW3R3fjDKbmfybZ5eFVPYRjJk5zy2j6ucL599FcaDB88nu 9QvtPApJPV70RDqib8yGEGIh2c2cGxqw1k5CA= Date: Tue, 1 Jun 2010 06:46:55 -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: <20100601134655.GA1281@gvim.org> Reply-To: markgross@thegnar.org References: <201005312338.55109.rjw@sisk.pl> <20100531232617.GF31155@gvim.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20100531232617.GF31155@gvim.org> 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 04:26:17PM -0700, mark gross wrote: > 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. > um, the notifiers that are currently used may not be cool in atomic context :( --mgross > --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