From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759267Ab3EBBnH (ORCPT ); Wed, 1 May 2013 21:43:07 -0400 Received: from mail-qe0-f73.google.com ([209.85.128.73]:62485 "EHLO mail-qe0-f73.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759014Ab3EBBnA (ORCPT ); Wed, 1 May 2013 21:43:00 -0400 X-Greylist: delayed 463 seconds by postgrey-1.27 at vger.kernel.org; Wed, 01 May 2013 21:43:00 EDT From: Colin Cross To: linux-pm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, "Rafael J. Wysocki" , arve@android.com, Tejun Heo , Oleg Nesterov , Colin Cross , Len Brown , Pavel Machek Subject: [PATCH v2 01/10] freezer: shorten freezer sleep time using exponential backoff Date: Wed, 1 May 2013 18:34:59 -0700 Message-Id: <1367458508-9133-2-git-send-email-ccross@android.com> X-Mailer: git-send-email 1.8.2.1 In-Reply-To: <1367458508-9133-1-git-send-email-ccross@android.com> References: <1367458508-9133-1-git-send-email-ccross@android.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org All tasks can easily be frozen in under 10 ms, switch to using an initial 1 ms sleep followed by exponential backoff until 8 ms. Also convert the printed time to ms instead of centiseconds. Signed-off-by: Colin Cross --- kernel/power/process.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) diff --git a/kernel/power/process.c b/kernel/power/process.c index 98088e0..eb7e6c1 100644 --- a/kernel/power/process.c +++ b/kernel/power/process.c @@ -30,9 +30,10 @@ static int try_to_freeze_tasks(bool user_only) unsigned int todo; bool wq_busy = false; struct timeval start, end; - u64 elapsed_csecs64; - unsigned int elapsed_csecs; + u64 elapsed_msecs64; + unsigned int elapsed_msecs; bool wakeup = false; + int sleep_usecs = USEC_PER_MSEC; do_gettimeofday(&start); @@ -70,20 +71,22 @@ static int try_to_freeze_tasks(bool user_only) * We need to retry, but first give the freezing tasks some * time to enter the refrigerator. */ - msleep(10); + usleep_range(sleep_usecs / 2, sleep_usecs); + if (sleep_usecs < 8 * USEC_PER_MSEC) + sleep_usecs *= 2; } do_gettimeofday(&end); - elapsed_csecs64 = timeval_to_ns(&end) - timeval_to_ns(&start); - do_div(elapsed_csecs64, NSEC_PER_SEC / 100); - elapsed_csecs = elapsed_csecs64; + elapsed_msecs64 = timeval_to_ns(&end) - timeval_to_ns(&start); + do_div(elapsed_msecs64, NSEC_PER_MSEC); + elapsed_msecs = elapsed_msecs64; if (todo) { printk("\n"); - printk(KERN_ERR "Freezing of tasks %s after %d.%02d seconds " + printk(KERN_ERR "Freezing of tasks %s after %d.%03d seconds " "(%d tasks refusing to freeze, wq_busy=%d):\n", wakeup ? "aborted" : "failed", - elapsed_csecs / 100, elapsed_csecs % 100, + elapsed_msecs / 1000, elapsed_msecs % 1000, todo - wq_busy, wq_busy); if (!wakeup) { @@ -96,8 +99,8 @@ static int try_to_freeze_tasks(bool user_only) read_unlock(&tasklist_lock); } } else { - printk("(elapsed %d.%02d seconds) ", elapsed_csecs / 100, - elapsed_csecs % 100); + printk("(elapsed %d.%03d seconds) ", elapsed_msecs / 1000, + elapsed_msecs % 1000); } return todo ? -EBUSY : 0; -- 1.8.2.1