From nobody Wed Dec 17 00:33:16 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 538BEC7618E for ; Sat, 22 Apr 2023 07:43:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229567AbjDVHn3 (ORCPT ); Sat, 22 Apr 2023 03:43:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41860 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229504AbjDVHn1 (ORCPT ); Sat, 22 Apr 2023 03:43:27 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2ACC419BD; Sat, 22 Apr 2023 00:43:25 -0700 (PDT) Date: Sat, 22 Apr 2023 07:43:22 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1682149403; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=X9vMKu/RlNQ7C/4jlltWW/zd/41Ilk8l/QMNavq8fmY=; b=Q1CBR2tPwFJBi8heCUlh1cmDDTJlrKmd8OFeuZjrtT0/9VcH6xY+AjVuio7tzjnpSKQ+SZ AmBKBGxKR6Iv7iU3jqYHisQn4lRgSqn3d0gycPM9HL0/zKTpSAP5WiDBWvnOdrbI3knvZv FV7QGbqFgeY3MEkZ2p98Glq3iJG7UoJK5D6PbWhi0ebNOZAxWngg8TAH5g+RbBdc+hPBCr 5XEMe6pZRR/IM2dAmWeKcxPedFB6VJPI4yXaX3T+X8Scg5sAusj1tvkI2VmmkzSEJjuv8x SsyGCh7yNaM7XipNzwQpqGRl1jcpA7nbjo5ADnEuO5TpwLTPp7rTkkp2dwoeDA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1682149403; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=X9vMKu/RlNQ7C/4jlltWW/zd/41Ilk8l/QMNavq8fmY=; b=ie2R8dax70DE6fdOwVFQDA3IbvnN2z9p7TABtCHGrykFyBjm3k012CWOBbGrKCc7x8FU0d JE9XbuhWRlYQksCg== From: "tip-bot2 for Aaron Thompson" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: sched/core] sched/clock: Fix local_clock() before sched_clock_init() Cc: Aaron Thompson , "Peter Zijlstra (Intel)" , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20230413175012.2201-1-dev@aaront.org> References: <20230413175012.2201-1-dev@aaront.org> MIME-Version: 1.0 Message-ID: <168214940282.404.16454263292921385535.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the sched/core branch of tip: Commit-ID: f31dcb152a3d0816e2f1deab4e64572336da197d Gitweb: https://git.kernel.org/tip/f31dcb152a3d0816e2f1deab4e6457233= 6da197d Author: Aaron Thompson AuthorDate: Thu, 13 Apr 2023 17:50:12=20 Committer: Peter Zijlstra CommitterDate: Fri, 21 Apr 2023 13:24:21 +02:00 sched/clock: Fix local_clock() before sched_clock_init() Have local_clock() return sched_clock() if sched_clock_init() has not yet run. sched_clock_cpu() has this check but it was not included in the new noinstr implementation of local_clock(). The effect can be seen on x86 with CONFIG_PRINTK_TIME enabled, for instance. scd->clock quickly reaches the value of TICK_NSEC and that value is returned until sched_clock_init() runs. dmesg without this patch: [ 0.000000] kvm-clock: ... [ 0.000002] kvm-clock: ... [ 0.000672] clocksource: ... [ 0.001000] tsc: ... [ 0.001000] e820: ... [ 0.001000] e820: ... ... [ 0.001000] ..TIMER: ... [ 0.001000] clocksource: ... [ 0.378956] Calibrating delay loop ... [ 0.379955] pid_max: ... dmesg with this patch: [ 0.000000] kvm-clock: ... [ 0.000001] kvm-clock: ... [ 0.000675] clocksource: ... [ 0.002685] tsc: ... [ 0.003331] e820: ... [ 0.004190] e820: ... ... [ 0.421939] ..TIMER: ... [ 0.422842] clocksource: ... [ 0.424582] Calibrating delay loop ... [ 0.425580] pid_max: ... Fixes: 776f22913b8e ("sched/clock: Make local_clock() noinstr") Signed-off-by: Aaron Thompson Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20230413175012.2201-1-dev@aaront.org --- kernel/sched/clock.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c index 5732fa7..b5cc2b5 100644 --- a/kernel/sched/clock.c +++ b/kernel/sched/clock.c @@ -300,6 +300,9 @@ noinstr u64 local_clock(void) if (static_branch_likely(&__sched_clock_stable)) return sched_clock() + __sched_clock_offset; =20 + if (!static_branch_likely(&sched_clock_running)) + return sched_clock(); + preempt_disable_notrace(); clock =3D sched_clock_local(this_scd()); preempt_enable_notrace();