Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755346Ab2BLB1e (ORCPT ); Sat, 11 Feb 2012 20:27:34 -0500 Received: from mail-pz0-f46.google.com ([209.85.210.46]:41240 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752547Ab2BLB1c (ORCPT ); Sat, 11 Feb 2012 20:27:32 -0500 Date: Sat, 11 Feb 2012 17:27:28 -0800 From: mark gross To: "Rafael J. Wysocki" Cc: Linux PM list , LKML , Magnus Damm , markgross@thegnar.org, Matthew Garrett , Greg KH , Arve =?iso-8859-1?B?SGr4bm5lduVn?= , John Stultz , Brian Swetland , Neil Brown , Alan Stern Subject: Re: [PATCH 4/8] PM / Sleep: Use wait queue to signal "no wakeup events in progress" Message-ID: <20120212012728.GB18742@gs62> Reply-To: markgross@thegnar.org References: <201202070200.55505.rjw@sisk.pl> <201202070204.19615.rjw@sisk.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201202070204.19615.rjw@sisk.pl> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3331 Lines: 97 On Tue, Feb 07, 2012 at 02:04:19AM +0100, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki > > The current wakeup source deactivation code doesn't do anything when > the counter of wakeup events in progress goes down to zero, which > requires pm_get_wakeup_count() to poll that counter periodically. > Although this reduces the average time it takes to deactivate a > wakeup source, it also may lead to a substantial amount of unnecessary > polling if there are extended periods of wakeup activity. Thus it > seems reasonable to use a wait queue for signaling the "no wakeup > events in progress" condition and remove the polling. > > Signed-off-by: Rafael J. Wysocki > --- > drivers/base/power/wakeup.c | 18 ++++++++++++++---- > 1 file changed, 14 insertions(+), 4 deletions(-) > > Index: linux/drivers/base/power/wakeup.c > =================================================================== > --- linux.orig/drivers/base/power/wakeup.c > +++ linux/drivers/base/power/wakeup.c > @@ -17,8 +17,6 @@ > > #include "power.h" > > -#define TIMEOUT 100 > - > /* > * If set, the suspend/hibernate code will abort transitions to a sleep state > * if wakeup events are registered during or immediately before the transition. > @@ -52,6 +50,8 @@ static void pm_wakeup_timer_fn(unsigned > > static LIST_HEAD(wakeup_sources); > > +static DECLARE_WAIT_QUEUE_HEAD(wakeup_count_wait_queue); > + > /** > * wakeup_source_create - Create a struct wakeup_source object. > * @name: Name of the new wakeup source. > @@ -84,7 +84,7 @@ void wakeup_source_destroy(struct wakeup > while (ws->active) { > spin_unlock_irq(&ws->lock); > > - schedule_timeout_interruptible(msecs_to_jiffies(TIMEOUT)); > + schedule_timeout_interruptible(msecs_to_jiffies(100)); Nit/ style comment: how is replacing a TIMEOUT macro with a magic number an improvement. (maybe timeout is a un-helpful name but 100 isn't any better. ) > > spin_lock_irq(&ws->lock); > } > @@ -411,6 +411,7 @@ EXPORT_SYMBOL_GPL(pm_stay_awake); > */ > static void wakeup_source_deactivate(struct wakeup_source *ws) > { > + unsigned int cnt, inpr; > ktime_t duration; > ktime_t now; > > @@ -444,6 +445,10 @@ static void wakeup_source_deactivate(str > * couter of wakeup events in progress simultaneously. > */ > atomic_add(MAX_IN_PROGRESS, &combined_event_count); > + > + split_counters(&cnt, &inpr); > + if (!inpr) > + wake_up_all(&wakeup_count_wait_queue); > } > > /** > @@ -624,14 +629,19 @@ bool pm_wakeup_pending(void) > bool pm_get_wakeup_count(unsigned int *count) > { > unsigned int cnt, inpr; > + DEFINE_WAIT(wait); > > for (;;) { > + prepare_to_wait(&wakeup_count_wait_queue, &wait, > + TASK_INTERRUPTIBLE); > split_counters(&cnt, &inpr); > if (inpr == 0 || signal_pending(current)) > break; > pm_wakeup_update_hit_counts(); > - schedule_timeout_interruptible(msecs_to_jiffies(TIMEOUT)); > + > + schedule(); > } > + finish_wait(&wakeup_count_wait_queue, &wait); > > split_counters(&cnt, &inpr); > *count = cnt; > -- 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/