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 56E7CECDFBB for ; Fri, 20 Jul 2018 10:01:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0B16920661 for ; Fri, 20 Jul 2018 10:01:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0B16920661 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 S1729890AbeGTKsy (ORCPT ); Fri, 20 Jul 2018 06:48:54 -0400 Received: from terminus.zytor.com ([198.137.202.136]:37217 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727243AbeGTKsy (ORCPT ); Fri, 20 Jul 2018 06:48:54 -0400 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id w6KA0oTt2614589 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Fri, 20 Jul 2018 03:00:50 -0700 Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id w6KA0oDt2614586; Fri, 20 Jul 2018 03:00:50 -0700 Date: Fri, 20 Jul 2018 03:00:50 -0700 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: tip-bot for Peter Zijlstra Message-ID: Cc: mingo@kernel.org, tglx@linutronix.de, peterz@infradead.org, linux-kernel@vger.kernel.org, pasha.tatashin@oracle.com, hpa@zytor.com Reply-To: tglx@linutronix.de, peterz@infradead.org, mingo@kernel.org, pasha.tatashin@oracle.com, hpa@zytor.com, linux-kernel@vger.kernel.org In-Reply-To: <20180720080911.GM2494@hirez.programming.kicks-ass.net> References: <20180720080911.GM2494@hirez.programming.kicks-ass.net> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/timers] sched/clock: Close a hole in sched_clock_init() Git-Commit-ID: 9407f5a7ee77c631d1e100436132437cf6237e45 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: 9407f5a7ee77c631d1e100436132437cf6237e45 Gitweb: https://git.kernel.org/tip/9407f5a7ee77c631d1e100436132437cf6237e45 Author: Peter Zijlstra AuthorDate: Fri, 20 Jul 2018 10:09:11 +0200 Committer: Thomas Gleixner CommitDate: Fri, 20 Jul 2018 11:58:00 +0200 sched/clock: Close a hole in sched_clock_init() All data required for the 'unstable' sched_clock must be set-up _before_ enabling it -- setting sched_clock_running. This includes the __gtod_offset but also a recent scd stamp. Make the gtod-offset update also set the csd stamp -- it requires the same two clock reads _anyway_. This doesn't hurt in the sched_clock_tick_stable() case and ensures sched_clock_init() gets everything set-up before use. Also switch to unconditional IRQ-disable/enable because the static key stuff already requires this is not ran with IRQs disabled. Fixes: 857baa87b642 ("sched/clock: Enable sched clock early") Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner Cc: Pavel Tatashin 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/20180720080911.GM2494@hirez.programming.kicks-ass.net --- kernel/sched/clock.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c index c5c47ad3f386..811a39aca1ce 100644 --- a/kernel/sched/clock.c +++ b/kernel/sched/clock.c @@ -197,13 +197,14 @@ void clear_sched_clock_stable(void) static void __sched_clock_gtod_offset(void) { - __gtod_offset = (sched_clock() + __sched_clock_offset) - ktime_get_ns(); + struct sched_clock_data *scd = this_scd(); + + __scd_stamp(scd); + __gtod_offset = (scd->tick_raw + __sched_clock_offset) - scd->tick_gtod; } void __init sched_clock_init(void) { - unsigned long flags; - /* * Set __gtod_offset such that once we mark sched_clock_running, * sched_clock_tick() continues where sched_clock() left off. @@ -211,16 +212,11 @@ void __init sched_clock_init(void) * Even if TSC is buggered, we're still UP at this point so it * can't really be out of sync. */ - local_irq_save(flags); + local_irq_disable(); __sched_clock_gtod_offset(); - local_irq_restore(flags); + local_irq_enable(); static_branch_inc(&sched_clock_running); - - /* Now that sched_clock_running is set adjust scd */ - local_irq_save(flags); - sched_clock_tick(); - local_irq_restore(flags); } /* * We run this as late_initcall() such that it runs after all built-in drivers,