From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4F74BC00449 for ; Fri, 5 Oct 2018 17:50:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BD3422084D for ; Fri, 5 Oct 2018 17:50:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BD3422084D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728916AbeJFAuY (ORCPT ); Fri, 5 Oct 2018 20:50:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:58322 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727957AbeJFAuY (ORCPT ); Fri, 5 Oct 2018 20:50:24 -0400 Received: from gandalf.local.home (cpe-66-24-56-78.stny.res.rr.com [66.24.56.78]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1D11E206B2; Fri, 5 Oct 2018 17:50:37 +0000 (UTC) Date: Fri, 5 Oct 2018 13:50:35 -0400 From: Steven Rostedt To: Peng Hao Cc: mingo@redhat.com, peterz@infradead.org, andrea.parri@amarulasolutions.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] sched/dl : return accurate release rq lock info Message-ID: <20181005135035.10a99573@gandalf.local.home> In-Reply-To: <1538788117-45448-1-git-send-email-peng.hao2@zte.com.cn> References: <1538788117-45448-1-git-send-email-peng.hao2@zte.com.cn> X-Mailer: Claws Mail 3.16.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 6 Oct 2018 09:08:37 +0800 Peng Hao wrote: > find_lock_later_rq may or not releease rq lock when return > later_rq=NULL, but it is fuzzy. > If not releasing rq lock, it is unnecessary to re-call > pick_next_pushable_dl_task. > > Signed-off-by: Peng Hao Reviewed-by: Steven Rostedt (VMware) -- Steve > --- > kernel/sched/deadline.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c > index 997ea7b..8e875ec 100644 > --- a/kernel/sched/deadline.c > +++ b/kernel/sched/deadline.c > @@ -1979,7 +1979,7 @@ static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq) > !dl_task(task) || > !task_on_rq_queued(task))) { > double_unlock_balance(rq, later_rq); > - later_rq = NULL; > + later_rq = RETRY_TASK; > break; > } > } > @@ -2063,7 +2063,9 @@ static int push_dl_task(struct rq *rq) > > /* Will lock the rq it'll find */ > later_rq = find_lock_later_rq(next_task, rq); > - if (!later_rq) { > + if (!later_rq) > + goto out; > + if (later_rq == RETRY_TASK) { > struct task_struct *task; > > /*