Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752348Ab0D1FIH (ORCPT ); Wed, 28 Apr 2010 01:08:07 -0400 Received: from ksp.mff.cuni.cz ([195.113.26.206]:44849 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751715Ab0D1FIF (ORCPT ); Wed, 28 Apr 2010 01:08:05 -0400 Date: Wed, 28 Apr 2010 07:07:53 +0200 From: Pavel Machek To: Arve Hj??nnev??g Cc: linux-pm@lists.linux-foundation.org, linux-kernel@vger.kernel.org, "Rafael J. Wysocki" , Alan Stern , Tejun Heo , Oleg Nesterov , Len Brown , Andrew Morton , David Rientjes , Matt Helsley Subject: Re: [PATCH 3/8] PM: suspend_block: Abort task freezing if a suspend_blocker is active. Message-ID: <20100428050753.GA2527@ucw.cz> References: <1272429119-12103-1-git-send-email-arve@android.com> <1272429119-12103-2-git-send-email-arve@android.com> <1272429119-12103-3-git-send-email-arve@android.com> <1272429119-12103-4-git-send-email-arve@android.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1272429119-12103-4-git-send-email-arve@android.com> 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: 2629 Lines: 76 On Tue 2010-04-27 21:31:54, Arve Hj??nnev??g wrote: > If a suspend_blocker is active, suspend will fail anyway. Since > try_to_freeze_tasks can take up to 20 seconds to complete or fail, aborting > as soon as someone blocks suspend (e.g. from an interrupt handler) improves > the worst case wakeup latency. > > On an older kernel where task freezing could fail for processes attached > to a debugger, this fixed a problem where the device sometimes hung for > 20 seconds before the screen turned on. > > Signed-off-by: Arve Hj??nnev??g ack. > --- > kernel/power/process.c | 12 ++++++++++-- > 1 files changed, 10 insertions(+), 2 deletions(-) > > diff --git a/kernel/power/process.c b/kernel/power/process.c > index 71ae290..d8ebd50 100644 > --- a/kernel/power/process.c > +++ b/kernel/power/process.c > @@ -15,6 +15,7 @@ > #include > #include > #include > +#include > > /* > * Timeout for stopping processes > @@ -38,6 +39,7 @@ static int try_to_freeze_tasks(bool sig_only) > struct timeval start, end; > u64 elapsed_csecs64; > unsigned int elapsed_csecs; > + bool wakeup = false; > > do_gettimeofday(&start); > > @@ -63,6 +65,10 @@ static int try_to_freeze_tasks(bool sig_only) > todo++; > } while_each_thread(g, p); > read_unlock(&tasklist_lock); > + if (todo && suspend_is_blocked()) { > + wakeup = true; > + break; > + } > if (!todo || time_after(jiffies, end_time)) > break; > > @@ -85,13 +91,15 @@ static int try_to_freeze_tasks(bool sig_only) > * but it cleans up leftover PF_FREEZE requests. > */ > printk("\n"); > - printk(KERN_ERR "Freezing of tasks failed after %d.%02d seconds " > + printk(KERN_ERR "Freezing of tasks %s after %d.%02d seconds " > "(%d tasks refusing to freeze):\n", > + wakeup ? "aborted" : "failed", > elapsed_csecs / 100, elapsed_csecs % 100, todo); > read_lock(&tasklist_lock); > do_each_thread(g, p) { > task_lock(p); > - if (freezing(p) && !freezer_should_skip(p)) > + if (freezing(p) && !freezer_should_skip(p) > + && elapsed_csecs > 100) > sched_show_task(p); > cancel_freezing(p); > task_unlock(p); -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- 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/