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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 1159AECDFB8 for ; Thu, 19 Jul 2018 22:34:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B169620673 for ; Thu, 19 Jul 2018 22:34:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B169620673 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=zytor.com 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 S1731492AbeGSXT0 (ORCPT ); Thu, 19 Jul 2018 19:19:26 -0400 Received: from terminus.zytor.com ([198.137.202.136]:58321 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731065AbeGSXT0 (ORCPT ); Thu, 19 Jul 2018 19:19:26 -0400 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id w6JMXtKj2439926 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Thu, 19 Jul 2018 15:33:55 -0700 Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id w6JMXtst2439922; Thu, 19 Jul 2018 15:33:55 -0700 Date: Thu, 19 Jul 2018 15:33:55 -0700 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: tip-bot for Pavel Tatashin Message-ID: Cc: tglx@linutronix.de, linux-kernel@vger.kernel.org, peterz@infradead.org, mingo@kernel.org, pasha.tatashin@oracle.com, hpa@zytor.com Reply-To: linux-kernel@vger.kernel.org, peterz@infradead.org, tglx@linutronix.de, pasha.tatashin@oracle.com, hpa@zytor.com, mingo@kernel.org In-Reply-To: <20180719205545.16512-25-pasha.tatashin@oracle.com> References: <20180719205545.16512-25-pasha.tatashin@oracle.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/timers] sched/clock: Use static key for sched_clock_running Git-Commit-ID: 46457ea464f5341d1f9dad8dd213805d45f7f117 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 46457ea464f5341d1f9dad8dd213805d45f7f117 Gitweb: https://git.kernel.org/tip/46457ea464f5341d1f9dad8dd213805d45f7f117 Author: Pavel Tatashin AuthorDate: Thu, 19 Jul 2018 16:55:43 -0400 Committer: Thomas Gleixner CommitDate: Fri, 20 Jul 2018 00:02:43 +0200 sched/clock: Use static key for sched_clock_running sched_clock_running may be read every time sched_clock_cpu() is called. Yet, this variable is updated only twice during boot, and never changes again, therefore it is better to make it a static key. Signed-off-by: Pavel Tatashin Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra Cc: steven.sistare@oracle.com Cc: daniel.m.jordan@oracle.com Cc: linux@armlinux.org.uk Cc: schwidefsky@de.ibm.com Cc: heiko.carstens@de.ibm.com Cc: john.stultz@linaro.org Cc: sboyd@codeaurora.org Cc: hpa@zytor.com Cc: douly.fnst@cn.fujitsu.com Cc: prarit@redhat.com Cc: feng.tang@intel.com Cc: pmladek@suse.com Cc: gnomes@lxorguk.ukuu.org.uk Cc: linux-s390@vger.kernel.org Cc: boris.ostrovsky@oracle.com Cc: jgross@suse.com Cc: pbonzini@redhat.com Link: https://lkml.kernel.org/r/20180719205545.16512-25-pasha.tatashin@oracle.com --- kernel/sched/clock.c | 16 ++++++++-------- kernel/sched/debug.c | 2 -- 2 files changed, 8 insertions(+), 10 deletions(-) diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c index 422cd63f8f17..c5c47ad3f386 100644 --- a/kernel/sched/clock.c +++ b/kernel/sched/clock.c @@ -67,7 +67,7 @@ unsigned long long __weak sched_clock(void) } EXPORT_SYMBOL_GPL(sched_clock); -__read_mostly int sched_clock_running; +static DEFINE_STATIC_KEY_FALSE(sched_clock_running); #ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK /* @@ -191,7 +191,7 @@ void clear_sched_clock_stable(void) smp_mb(); /* matches sched_clock_init_late() */ - if (sched_clock_running == 2) + if (static_key_count(&sched_clock_running.key) == 2) __clear_sched_clock_stable(); } @@ -215,7 +215,7 @@ void __init sched_clock_init(void) __sched_clock_gtod_offset(); local_irq_restore(flags); - sched_clock_running = 1; + static_branch_inc(&sched_clock_running); /* Now that sched_clock_running is set adjust scd */ local_irq_save(flags); @@ -228,7 +228,7 @@ void __init sched_clock_init(void) */ static int __init sched_clock_init_late(void) { - sched_clock_running = 2; + static_branch_inc(&sched_clock_running); /* * Ensure that it is impossible to not do a static_key update. * @@ -373,7 +373,7 @@ u64 sched_clock_cpu(int cpu) if (sched_clock_stable()) return sched_clock() + __sched_clock_offset; - if (unlikely(!sched_clock_running)) + if (!static_branch_unlikely(&sched_clock_running)) return sched_clock(); preempt_disable_notrace(); @@ -396,7 +396,7 @@ void sched_clock_tick(void) if (sched_clock_stable()) return; - if (unlikely(!sched_clock_running)) + if (!static_branch_unlikely(&sched_clock_running)) return; lockdep_assert_irqs_disabled(); @@ -455,13 +455,13 @@ EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event); void __init sched_clock_init(void) { - sched_clock_running = 1; + static_branch_inc(&sched_clock_running); generic_sched_clock_init(); } u64 sched_clock_cpu(int cpu) { - if (unlikely(!sched_clock_running)) + if (!static_branch_unlikely(&sched_clock_running)) return 0; return sched_clock(); diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index e593b4118578..b0212f489a33 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -623,8 +623,6 @@ void print_dl_rq(struct seq_file *m, int cpu, struct dl_rq *dl_rq) #undef PU } -extern __read_mostly int sched_clock_running; - static void print_cpu(struct seq_file *m, int cpu) { struct rq *rq = cpu_rq(cpu);