From nobody Sun May 10 17:53:31 2026 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 75531C433EF for ; Wed, 27 Apr 2022 18:43:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231238AbiD0SrC (ORCPT ); Wed, 27 Apr 2022 14:47:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46598 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229854AbiD0SqG (ORCPT ); Wed, 27 Apr 2022 14:46:06 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A89327522C; Wed, 27 Apr 2022 11:27:22 -0700 (PDT) Date: Wed, 27 Apr 2022 18:27:20 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1651084041; 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=6iIPFt3fKApC2NPRJ5BU2GAYeO/pyyhPu4W8hcSJa8g=; b=0KSiNe4suFMu52SkzV8jseuYiYH8K1W97+TjS+qjqAVv1pJuHDrbISOcqUBYKEBpmH074X U7UbUXElkMpRr455VhRL66F/B96h6wU8VV6zG2SlzlWG9cYwFOCUbBx9wWqwe4JQMdaqcw d3ArNvOP5GiGXTeDdI3U0TdBLd2q0iRY6WvVbqrV1TySTEXKnKcoVlBY+rxnXHWkX45IFF 1xnKriEfcbgGi+919xtzvl1Ndt2gmk2EaVF+kafbUtXvBIsXx+5WQak/MEeieiNeRyScXX fsFtYdBp5Uyy4DnlpPN38UsdVU7rJGvN/TpHTsFngNYG6FmCR2gJ7LTKuLrRkw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1651084041; 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=6iIPFt3fKApC2NPRJ5BU2GAYeO/pyyhPu4W8hcSJa8g=; b=hH+y8TBnlyq2Jb8ptvlcYLKMz29QHRa1yUFApg5HMAIc32hABsszBv+XaHcp2iB0SDQKiK 58jNlT0UsO/XflDw== From: "tip-bot2 for Thomas Gleixner" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/cleanups] x86/aperfmperf: Integrate the fallback code from show_cpuinfo() Cc: "Rafael J. Wysocki" , Thomas Gleixner , Doug Smythies , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <87pml5180p.ffs@tglx> References: <87pml5180p.ffs@tglx> MIME-Version: 1.0 Message-ID: <165108404020.4207.6950218577466647606.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 x86/cleanups branch of tip: Commit-ID: fb4c77c21aba03677f283acda3cae748ef866abf Gitweb: https://git.kernel.org/tip/fb4c77c21aba03677f283acda3cae748e= f866abf Author: Thomas Gleixner AuthorDate: Mon, 25 Apr 2022 17:45:42 +02:00 Committer: Thomas Gleixner CommitterDate: Wed, 27 Apr 2022 20:22:20 +02:00 x86/aperfmperf: Integrate the fallback code from show_cpuinfo() Due to the avoidance of IPIs to idle CPUs arch_freq_get_on_cpu() can return 0 when the last sample was too long ago. show_cpuinfo() has a fallback to cpufreq_quick_get() and if that fails to return cpu_khz, but the readout code for the per CPU scaling frequency in sysfs does not. Move that fallback into arch_freq_get_on_cpu() so the behaviour is the same when reading /proc/cpuinfo and /sys/..../cur_scaling_freq. Suggested-by: "Rafael J. Wysocki" Signed-off-by: Thomas Gleixner Tested-by: Doug Smythies Link: https://lore.kernel.org/r/87pml5180p.ffs@tglx --- arch/x86/kernel/cpu/aperfmperf.c | 10 +++++++--- arch/x86/kernel/cpu/proc.c | 7 +------ 2 files changed, 8 insertions(+), 9 deletions(-) diff --git a/arch/x86/kernel/cpu/aperfmperf.c b/arch/x86/kernel/cpu/aperfmp= erf.c index b15c884..1f60a2b 100644 --- a/arch/x86/kernel/cpu/aperfmperf.c +++ b/arch/x86/kernel/cpu/aperfmperf.c @@ -405,12 +405,12 @@ void arch_scale_freq_tick(void) unsigned int arch_freq_get_on_cpu(int cpu) { struct aperfmperf *s =3D per_cpu_ptr(&cpu_samples, cpu); + unsigned int seq, freq; unsigned long last; - unsigned int seq; u64 acnt, mcnt; =20 if (!cpu_feature_enabled(X86_FEATURE_APERFMPERF)) - return 0; + goto fallback; =20 do { seq =3D raw_read_seqcount_begin(&s->seq); @@ -424,9 +424,13 @@ unsigned int arch_freq_get_on_cpu(int cpu) * which covers idle and NOHZ full CPUs. */ if (!mcnt || (jiffies - last) > MAX_SAMPLE_AGE) - return 0; + goto fallback; =20 return div64_u64((cpu_khz * acnt), mcnt); + +fallback: + freq =3D cpufreq_quick_get(cpu); + return freq ? freq : cpu_khz; } =20 static int __init bp_init_aperfmperf(void) diff --git a/arch/x86/kernel/cpu/proc.c b/arch/x86/kernel/cpu/proc.c index 0a0ee55..099b6f0 100644 --- a/arch/x86/kernel/cpu/proc.c +++ b/arch/x86/kernel/cpu/proc.c @@ -86,12 +86,7 @@ static int show_cpuinfo(struct seq_file *m, void *v) if (cpu_has(c, X86_FEATURE_TSC)) { unsigned int freq =3D arch_freq_get_on_cpu(cpu); =20 - if (!freq) - freq =3D cpufreq_quick_get(cpu); - if (!freq) - freq =3D cpu_khz; - seq_printf(m, "cpu MHz\t\t: %u.%03u\n", - freq / 1000, (freq % 1000)); + seq_printf(m, "cpu MHz\t\t: %u.%03u\n", freq / 1000, (freq % 1000)); } =20 /* Cache size */