Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755527AbdCWCNp (ORCPT ); Wed, 22 Mar 2017 22:13:45 -0400 Received: from LGEAMRELO12.lge.com ([156.147.23.52]:33966 "EHLO lgeamrelo12.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751087AbdCWCNl (ORCPT ); Wed, 22 Mar 2017 22:13:41 -0400 X-Original-SENDERIP: 156.147.1.125 X-Original-MAILFROM: byungchul.park@lge.com X-Original-SENDERIP: 165.244.249.23 X-Original-MAILFROM: byungchul.park@lge.com X-Original-SENDERIP: 10.177.222.33 X-Original-MAILFROM: byungchul.park@lge.com From: Byungchul Park To: , CC: , , , Subject: [PATCH v3 2/3] sched/deadline: Add support for SD_PREFER_SIBLING on find_later_rq() Date: Thu, 23 Mar 2017 11:12:48 +0900 Message-ID: <1490235169-370-2-git-send-email-byungchul.park@lge.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1490235169-370-1-git-send-email-byungchul.park@lge.com> References: <1490235169-370-1-git-send-email-byungchul.park@lge.com> X-MIMETrack: Itemize by SMTP Server on LGEKRMHUB04/LGE/LG Group(Release 8.5.3FP6|November 21, 2013) at 2017/03/23 11:13:29, Serialize by Router on LGEKRMHUB04/LGE/LG Group(Release 8.5.3FP6|November 21, 2013) at 2017/03/23 11:13:31, Serialize complete at 2017/03/23 11:13:31 MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1656 Lines: 53 It would be better to avoid pushing tasks to other cpu within a SD_PREFER_SIBLING domain, instead, get more chances to check other siblings. Signed-off-by: Byungchul Park --- kernel/sched/deadline.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 49c93b9..ec15a8b 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1325,6 +1325,7 @@ static int find_later_rq(struct task_struct *task) struct cpumask *later_mask = this_cpu_cpumask_var_ptr(local_cpu_mask_dl); int this_cpu = smp_processor_id(); int cpu = task_cpu(task); + int fallback_cpu = -1; /* Make sure the mask is initialized first */ if (unlikely(!later_mask)) @@ -1385,6 +1386,15 @@ static int find_later_rq(struct task_struct *task) * already under consideration through later_mask. */ if (closest_cpu < nr_cpu_ids) { + /* + * If current domain is SD_PREFER_SIBLING + * flaged, we have to get more chances to + * check other siblings. + */ + if (sd->flags & SD_PREFER_SIBLING) { + fallback_cpu = closest_cpu; + continue; + } rcu_read_unlock(); return closest_cpu; } @@ -1393,6 +1403,13 @@ static int find_later_rq(struct task_struct *task) rcu_read_unlock(); /* + * If fallback_cpu is valid, all our guesses failed *except* for + * SD_PREFER_SIBLING domain. Now, we can return the fallback cpu. + */ + if (fallback_cpu != -1) + return fallback_cpu; + + /* * At this point, all our guesses failed, we just return * 'something', and let the caller sort the things out. */ -- 1.9.1