Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754886AbbDGNsX (ORCPT ); Tue, 7 Apr 2015 09:48:23 -0400 Received: from eu-smtp-delivery-143.mimecast.com ([146.101.78.143]:21619 "EHLO eu-smtp-delivery-143.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754123AbbDGNsU convert rfc822-to-8bit (ORCPT ); Tue, 7 Apr 2015 09:48:20 -0400 Message-ID: <5523E01C.9020808@arm.com> Date: Tue, 07 Apr 2015 14:48:12 +0100 From: Juri Lelli User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: Wanpeng Li , Ingo Molnar , Peter Zijlstra CC: "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 3/7] sched/deadline: reduce rq lock contention by eliminating locking of non-feasible target References: <1428310399-13489-1-git-send-email-wanpeng.li@linux.intel.com> <1428310399-13489-3-git-send-email-wanpeng.li@linux.intel.com> In-Reply-To: <1428310399-13489-3-git-send-email-wanpeng.li@linux.intel.com> X-OriginalArrivalTime: 07 Apr 2015 13:48:13.0323 (UTC) FILETIME=[7DE8D5B0:01D07139] X-MC-Unique: cSSCIpsjT02DmzZJ7D8O4g-1 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1396 Lines: 43 Hi, On 06/04/2015 09:53, Wanpeng Li wrote: > This patch adds check that prevents futile attempts to move dl tasks to > a CPU with active tasks of equal or earlier deadline. The same behavior as > commit 80e3d87b2c55 ("sched/rt: Reduce rq lock contention by eliminating > locking of non-feasible target") for rt class. > This commit introduced also this kind of check in find_lock_lowest_rq(). Don't we need something like this in find_lock_later_rq() as well? Thanks, - Juri > Signed-off-by: Wanpeng Li > --- > kernel/sched/deadline.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c > index 3bd3158..b8b9355 100644 > --- a/kernel/sched/deadline.c > +++ b/kernel/sched/deadline.c > @@ -1012,7 +1012,9 @@ select_task_rq_dl(struct task_struct *p, int cpu, int sd_flag, int flags) > (p->nr_cpus_allowed > 1)) { > int target = find_later_rq(p); > > - if (target != -1) > + if (target != -1 && > + dl_time_before(p->dl.deadline, > + cpu_rq(target)->dl.earliest_dl.curr)) > cpu = target; > } > rcu_read_unlock(); > -- 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/