From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754737AbcGEOUU (ORCPT ); Tue, 5 Jul 2016 10:20:20 -0400 Received: from smtprelay0215.hostedemail.com ([216.40.44.215]:45539 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751598AbcGEOUR (ORCPT ); Tue, 5 Jul 2016 10:20:17 -0400 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Spam-Summary: 2,0,0,,d41d8cd98f00b204,rostedt@goodmis.org,:::::::::,RULES_HIT:41:355:379:541:599:800:960:973:988:989:1260:1277:1311:1313:1314:1345:1359:1437:1515:1516:1518:1534:1542:1593:1594:1711:1730:1747:1777:1792:2393:2553:2559:2562:3138:3139:3140:3141:3142:3354:3622:3865:3866:3867:3868:3870:4321:4605:5007:6119:6261:7875:7903:9040:10004:10400:10848:10967:11026:11232:11658:11914:12043:12296:12438:12517:12519:12555:12663:12740:13149:13230:13439:14096:14097:14180:14181:14659:14721:14822:21080:21324:21433:30054:30090:30091,0,RBL:none,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:0,DNSBL:none,Custom_rules:0:0:0,LFtime:3,LUA_SUMMARY:none X-HE-Tag: pull60_3c675e08f8938 X-Filterd-Recvd-Size: 3257 Date: Tue, 5 Jul 2016 10:20:13 -0400 From: Steven Rostedt To: Juri Lelli Cc: peterz@infradead.org, linux-kernel@vger.kernel.org, mingo@redhat.com, luca.abeni@unitn.it Subject: Re: [PATCH v2] sched/deadline: remove useless param from setup_new_dl_entity Message-ID: <20160705102013.25a1a1dc@gandalf.local.home> In-Reply-To: <1467227263-31349-1-git-send-email-juri.lelli@arm.com> References: <1467227263-31349-1-git-send-email-juri.lelli@arm.com> X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; 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 List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 29 Jun 2016 20:07:43 +0100 Juri Lelli wrote: > --- > kernel/sched/deadline.c | 14 +++++++++++--- > 1 file changed, 11 insertions(+), 3 deletions(-) > > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c > index fcb7f0217ff4..2000ad2294d5 100644 > --- a/kernel/sched/deadline.c > +++ b/kernel/sched/deadline.c > @@ -346,11 +346,12 @@ static void check_preempt_curr_dl(struct rq *rq, struct task_struct *p, > * one, and to (try to!) reconcile itself with its own scheduling > * parameters. > */ > -static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se, > - struct sched_dl_entity *pi_se) > +static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se) > { > struct dl_rq *dl_rq = dl_rq_of_se(dl_se); > struct rq *rq = rq_of_dl_rq(dl_rq); > + struct task_struct *pi_task = rt_mutex_get_top_task(dl_task_of(dl_se)); > + struct sched_dl_entity *pi_se = dl_se; > > WARN_ON(dl_time_before(rq_clock(rq), dl_se->deadline)); > > @@ -363,6 +364,13 @@ static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se, > return; > > /* > + * Use the scheduling parameters of the top pi-waiter task, > + * if we have one from which we can inherit a deadline. > + */ > + if (pi_task && dl_se->dl_boosted && dl_prio(pi_task->normal_prio)) > + pi_se = &pi_task->dl; > + OK, I'm micro-optimizing now, but hey, isn't this a fast path? What about changing the above to: struct task_struct *pi_task; [...] if (dl_se->dl_boosted && dl_prio(pi_task->normal_prio && (pi_task = rt_mutex_get_top_task(dl_task_of(dl_se))) pe_se = &pi_task->dl; This way we don't need to do any work of looking at rt_mutex_get_top_task() for the normal case. -- Steve > + /* > * We use the regular wall clock time to set deadlines in the > * future; in fact, we must consider execution overheads (time > * spent on hardirq context, etc.). > @@ -1721,7 +1729,7 @@ static void switched_from_dl(struct rq *rq, struct task_struct *p) > static void switched_to_dl(struct rq *rq, struct task_struct *p) > { > if (dl_time_before(p->dl.deadline, rq_clock(rq))) > - setup_new_dl_entity(&p->dl, &p->dl); > + setup_new_dl_entity(&p->dl); > > if (task_on_rq_queued(p) && rq->curr != p) { > #ifdef CONFIG_SMP