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=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 C0954C433B4 for ; Sat, 17 Apr 2021 12:28:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 964FA611AF for ; Sat, 17 Apr 2021 12:28:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236242AbhDQM2x (ORCPT ); Sat, 17 Apr 2021 08:28:53 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:35054 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235901AbhDQM2u (ORCPT ); Sat, 17 Apr 2021 08:28:50 -0400 From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1618662503; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=0abE3J5vsoXiEgTyesb4PssHvHXbBvKJFFhaFzAtlkg=; b=YWa4DWKSzwHANiXj8IOp7ATpYHy9CzLBvMW3M5kbkCe9mdUzm4XssLiUYd4Nseg45YPlG2 +kqtvrSoF7tnf16dUWHk4gZqBqUkrhglzAqnan+rhuMTlewRApMk3po6derfvCbrcp/0qX 0mNZBqtdehc7hBMpDmQigRAmwiZDmPXIcmkgITTvppiJlYejKm3WipXo49Bigbab68f869 wR6WZhru3JslHnHa2V8L2Kqf01dMGMq6IsFZHzHmERmKKYkVlASKfevynmXJYEaqxee5YY sJBMkeVAjtKYeOq+uGhcnm1rJttreutVp6d1nTfhBhQLSPkkLufbssY81vQQDQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1618662503; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=0abE3J5vsoXiEgTyesb4PssHvHXbBvKJFFhaFzAtlkg=; b=3v8p3dWRhzejX1WCKGYYEX19kktknh93Ucr6zxO+wAwCnJjFhSvabZ80Ux2frc0IHgBy04 osAJ+T91kDE/UtAA== To: "Paul E. McKenney" Cc: linux-kernel@vger.kernel.org, john.stultz@linaro.org, sboyd@kernel.org, corbet@lwn.net, Mark.Rutland@arm.com, maz@kernel.org, kernel-team@fb.com, neeraju@codeaurora.org, ak@linux.intel.com, "Paul E. McKenney" , Chris Mason Subject: Re: [PATCH v8 clocksource 3/5] clocksource: Check per-CPU clock synchronization when marked unstable In-Reply-To: <20210414043602.2812981-3-paulmck@kernel.org> References: <20210414043435.GA2812539@paulmck-ThinkPad-P17-Gen-1> <20210414043602.2812981-3-paulmck@kernel.org> Date: Sat, 17 Apr 2021 14:28:22 +0200 Message-ID: <87v98lrt7d.ffs@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 13 2021 at 21:36, Paul E. McKenney wrote: > diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c > index 1fc0962c89c0..97eeaf164296 100644 > --- a/arch/x86/kernel/kvmclock.c > +++ b/arch/x86/kernel/kvmclock.c > @@ -169,7 +169,7 @@ struct clocksource kvm_clock = { > .read = kvm_clock_get_cycles, > .rating = 400, > .mask = CLOCKSOURCE_MASK(64), > - .flags = CLOCK_SOURCE_IS_CONTINUOUS, > + .flags = CLOCK_SOURCE_IS_CONTINUOUS | CLOCK_SOURCE_VERIFY_PERCPU, kvm_clock is not marked with CLOCK_SOURCE_MUST_VERIFY, so what's the point of adding this here? It's not subject to be monitored by the watchdog muck. > diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c > index f70dffc2771f..56289170753c 100644 > --- a/arch/x86/kernel/tsc.c > +++ b/arch/x86/kernel/tsc.c > @@ -1151,7 +1151,8 @@ static struct clocksource clocksource_tsc = { > .mask = CLOCKSOURCE_MASK(64), > .flags = CLOCK_SOURCE_IS_CONTINUOUS | > CLOCK_SOURCE_VALID_FOR_HRES | > - CLOCK_SOURCE_MUST_VERIFY, > + CLOCK_SOURCE_MUST_VERIFY | > + CLOCK_SOURCE_VERIFY_PERCPU, While this one is part of the horror show. > +static u64 csnow_mid; > +static cpumask_t cpus_ahead; > +static cpumask_t cpus_behind; > + > +static void clocksource_verify_one_cpu(void *csin) > +{ > + struct clocksource *cs = (struct clocksource *)csin; > + > + csnow_mid = cs->read(cs); > +} > + > +static void clocksource_verify_percpu(struct clocksource *cs) > +{ > + int64_t cs_nsec, cs_nsec_max, cs_nsec_min; > + u64 csnow_begin, csnow_end; > + bool firsttime = 1; > + int testcpu; > + s64 delta; > + int cpu; int testcpu, cpu; :)