From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760218Ab0FQXCd (ORCPT ); Thu, 17 Jun 2010 19:02:33 -0400 Received: from cantor.suse.de ([195.135.220.2]:52692 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755813Ab0FQXCc (ORCPT ); Thu, 17 Jun 2010 19:02:32 -0400 Subject: Re: [PATCH 3/3] pm_qos: only schedule work when in interrupt context From: James Bottomley To: Florian Mickler Cc: Frederic Weisbecker , Jonathan Corbet , markgross@thegnar.org, linville@tuxdriver.com, linux-kernel@vger.kernel.org, pm list , Thomas Gleixner In-Reply-To: <20100615192347.761f427a@schatten.dmk.lab> References: <1276266352.2862.70.camel@mulgrave.site> <1276526800-12362-3-git-send-email-florian@mickler.org> <20100615192347.761f427a@schatten.dmk.lab> Content-Type: text/plain; charset="UTF-8" Date: Thu, 17 Jun 2010 18:02:25 -0500 Message-ID: <1276815745.7398.359.camel@mulgrave.site> Mime-Version: 1.0 X-Mailer: Evolution 2.28.2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2010-06-15 at 19:23 +0200, Florian Mickler wrote: > Hi James! > > On Mon, 14 Jun 2010 16:46:40 +0200 > florian@mickler.org wrote: > > > With this patch we only schedule the work when in interrupt context. > > > > Before update_request was callable from interrupt-context there was a > > 1:1 relation between a change in the request-value and a notification. > > This patch restores that behaviour for all constraints that have update_request > > never called from interrupt context. > > > > The notifier mutex serializes calls to blocking_notifier_call_chain, so > > that we are serialized against any pending or currently executing notification. > > > > Signed-off-by: Florian Mickler > > --- > > kernel/pm_qos_params.c | 10 +++++++--- > > 1 files changed, 7 insertions(+), 3 deletions(-) > > > > diff --git a/kernel/pm_qos_params.c b/kernel/pm_qos_params.c > > index 9346906..c06cae9 100644 > > --- a/kernel/pm_qos_params.c > > +++ b/kernel/pm_qos_params.c > > @@ -152,11 +152,15 @@ static s32 min_compare(s32 v1, s32 v2) > > static void pm_qos_call_notifiers(struct pm_qos_object *o, > > unsigned long curr_value) > > { > > - schedule_work(&o->notify); > > - > > if (o->atomic_notifiers) > > atomic_notifier_call_chain(o->atomic_notifiers, > > - curr_value, NULL); > > + (unsigned long) curr_value, NULL); > > + > > + if (in_interrupt()) > > + schedule_work(&o->notify); > > + else > > + blocking_notifier_call_chain(o->blocking_notifiers, > > + (unsigned long) curr_value, NULL); > > } > > > > static void update_notify(struct work_struct *work) > > What about this? Is this ok? I don't know if it is benign to use > in_interrupt() here. I took this idea from the > execute_in_process_context() implementation. I think it will work ... but I still think it's over complex given the listed requirements (android seems to only want atomic notifiers from atomic contexts). > If this is ok, should I rebase them on your two pm_qos patches (plists > and the kzalloc removal)? Well, I would say yes. However, for more impartial advice, I'd wait and see what the pm maintainers want. > Did you already thought about some debugging stuff that would suffice > the android needs? I kind of thought about either registerieng some > notifier callback or using the perf/tracing infrastructure. > But I have not looked into it yet. I was just going to try the conversion when the wakelocks stuff was finally in and see if it worked in an android kernel. James