Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756581Ab0FAOFH (ORCPT ); Tue, 1 Jun 2010 10:05:07 -0400 Received: from mail-pw0-f46.google.com ([209.85.160.46]:61528 "EHLO mail-pw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756029Ab0FAOFF (ORCPT ); Tue, 1 Jun 2010 10:05:05 -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=n1mSdQTRJaeL/wt54iReA3LLVMxuVcATsDC+VPx61MQN0GmWiv8Btqnubl6J6L80GX N720t/IVN77T+0ZGSIrw3i8T4KjObrGys/OX06vNvVm+4U4EOcfwP02u/yXV9HrJ8QXs 4mCMQ72Zy2PH4nMyM69bzQWFnExnWgNJKdufE= Date: Tue, 1 Jun 2010 07:05:19 -0700 From: mark gross <640e9920@gmail.com> To: Florian Mickler Cc: markgross@thegnar.org, 640e9920@gmail.com, "Rafael J. Wysocki" , Arve =?iso-8859-1?B?SGr4bm5lduVn?= , Alan Stern , Peter Zijlstra , Linux PM , Brian Swetland , Alan Cox , Matthew Garrett , Thomas Gleixner , LKML , Ingo Molnar Subject: Re: [linux-pm] [PATCH 0/8] Suspend block api (version 8) Message-ID: <20100601140519.GC1281@gvim.org> Reply-To: markgross@thegnar.org References: <201005312338.55109.rjw@sisk.pl> <20100531232617.GF31155@gvim.org> <20100601090737.4bc243d9@schatten.dmk.lab> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20100601090737.4bc243d9@schatten.dmk.lab> 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 Content-Length: 4774 Lines: 134 On Tue, Jun 01, 2010 at 09:07:37AM +0200, Florian Mickler wrote: > On Mon, 31 May 2010 16:26:17 -0700 > mark gross <640e9920@gmail.com> wrote: > > > On Mon, May 31, 2010 at 11:38:55PM +0200, Rafael J. Wysocki wrote: > > > On Monday 31 May 2010, Arve Hj?nnev?g wrote: > > > > 2010/5/29 Alan Stern : > > > > > On Sat, 29 May 2010, Arve Hj?nnev?g 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 > > > > Well, the register call uses kzalloc. Apart from that I > think we're good. > > The outstanding list traversals can be fixed also. (see below) > > Cheers, > Flo > > From 66fdd76f8cc4be722dba3859ddadfe07e7a4b755 Mon Sep 17 00:00:00 2001 > From: Florian Mickler > Date: Tue, 1 Jun 2010 09:04:26 +0200 > Subject: [PATCH] pm_qos: remove unnecessary list-traversal > > The new extreme_value is only depending on the old extreme_value and > the changing value. > > Signed-off-by: Florian Mickler > --- > kernel/pm_qos_params.c | 20 ++++++++++++++------ > 1 files changed, 14 insertions(+), 6 deletions(-) > > diff --git a/kernel/pm_qos_params.c b/kernel/pm_qos_params.c > index f42d3f7..6618e2c 100644 > --- a/kernel/pm_qos_params.c > +++ b/kernel/pm_qos_params.c > @@ -136,6 +136,16 @@ static s32 min_compare(s32 v1, s32 v2) > } > > > +static void update_target_val(int pm_qos_class, s32 val) > +{ > + s32 extreme_value; > + s32 new_value; > + extreme_value = atomic_read(&pm_qos_array[pm_qos_class]->target_value); > + new_value = pm_qos_array[pm_qos_class]->comparitor(val,extreme_value); > + if (extreme_value != new_value) > + atomic_set(&pm_qos_array[pm_qos_class]->target_value,new_value); > +} > + Only works 1/2 the time, but I like the idea! It fails to get the righ answer when constraints are reduced. But, this idea is a good improvement i'll roll into the next pm_qos update! thanks! --mgross > static void update_target(int pm_qos_class) > { > s32 extreme_value; > @@ -227,8 +237,8 @@ struct pm_qos_request_list *pm_qos_add_request(int pm_qos_class, s32 value) > spin_lock_irqsave(&pm_qos_lock, flags); > list_add(&dep->list, > &pm_qos_array[pm_qos_class]->requests.list); > + update_target_val(pm_qos_class,dep->value); > spin_unlock_irqrestore(&pm_qos_lock, flags); > - update_target(pm_qos_class); > } > > return dep; > @@ -249,23 +259,21 @@ void pm_qos_update_request(struct pm_qos_request_list *pm_qos_req, > s32 new_value) > { > unsigned long flags; > - int pending_update = 0; > s32 temp; > > if (pm_qos_req) { /*guard against callers passing in null */ > + int target = pm_qos_req->pm_qos_class; > spin_lock_irqsave(&pm_qos_lock, flags); > if (new_value == PM_QOS_DEFAULT_VALUE) > - temp = pm_qos_array[pm_qos_req->pm_qos_class]->default_value; > + temp = pm_qos_array[target]->default_value; > else > temp = new_value; > > if (temp != pm_qos_req->value) { > - pending_update = 1; > pm_qos_req->value = temp; > + update_target_val(target,temp); > } > spin_unlock_irqrestore(&pm_qos_lock, flags); > - if (pending_update) > - update_target(pm_qos_req->pm_qos_class); > } > } > EXPORT_SYMBOL_GPL(pm_qos_update_request); > -- > 1.7.1 > -- 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/