From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 9723F1B0F1E; Tue, 21 Jan 2025 10:47:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737456455; cv=none; b=AWGtzA0YKlrb8tuw7QzMlNoquwNGHPhHMURkizg+ueYi10NB0IxRdpjwqn2JFf+klOX5RG3S+duLrUwC95IEH6HdPHEo0vXcPEVK8k07Ioy9gce8fTS5/FhLLzybZMCD9keyCSeYi40J+zeKYBpM6HiBkdKWxfVvNMcoEGPqIHw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737456455; c=relaxed/simple; bh=EWaUNnruHpal+zW0Tc0ycVqyE0sHBEGQZtpuE9Jg4dk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=UyydlAPCI/lXJYsmpCNZ6Ejn5i4lhuJ+Hin4rtLdxX6lSYFI7eGpKJkvR/zU/W1VHjRi27wrEjQDBxfXK8w89rFyHkSCtGoHQ7pmVqLCDMSLZF74Q8hh8JVacMe9HfODjq1FJr2KT4OPxZuXlbp+tetuMOcoqfyigN168DtnZaw= ARC-Authentication-Results:i=1; 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h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=lAopDuXA60YAgdosgvAgfkgCazTII9V7wWa/8Mlz02BIA7k/oczJScx2D4fM9nVLm YYkon7r8GCQhgmxjqvEaoSNBbUz6Jqatsr1fFT0NOE68Dlfag33/rqCcEcX2ZqnaJq jyxqxweMzxBITuutSmC4d3G0o8+GRUZMu39raYaM= Message-ID: Date: Tue, 21 Jan 2025 16:17:27 +0530 Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v9 1/5] cpufreq: Allow arch_freq_get_on_cpu to return an error To: Beata Michalska , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pm@vger.kernel.org, ionela.voinescu@arm.com, sudeep.holla@arm.com, will@kernel.org, catalin.marinas@arm.com, rafael@kernel.org, viresh.kumar@linaro.org Cc: sumitg@nvidia.com, yang@os.amperecomputing.com, vanshikonda@os.amperecomputing.com, lihuisong@huawei.com, zhanjie9@hisilicon.com References: <20250121084435.2839280-1-beata.michalska@arm.com> <20250121084435.2839280-2-beata.michalska@arm.com> Content-Language: en-US From: Prasanna Kumar T S M In-Reply-To: <20250121084435.2839280-2-beata.michalska@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 21-01-2025 14:14, Beata Michalska wrote: > Allow arch_freq_get_on_cpu to return an error for cases when retrieving > current CPU frequency is not possible, whether that being due to lack of > required arch support or due to other circumstances when the current > frequency cannot be determined at given point of time. > > Signed-off-by: Beata Michalska > --- > arch/x86/kernel/cpu/aperfmperf.c | 2 +- > arch/x86/kernel/cpu/proc.c | 7 +++++-- > drivers/cpufreq/cpufreq.c | 8 ++++---- > include/linux/cpufreq.h | 2 +- > 4 files changed, 11 insertions(+), 8 deletions(-) > > diff --git a/arch/x86/kernel/cpu/aperfmperf.c b/arch/x86/kernel/cpu/aperfmperf.c > index f642de2ebdac..6cf31a1649c4 100644 > --- a/arch/x86/kernel/cpu/aperfmperf.c > +++ b/arch/x86/kernel/cpu/aperfmperf.c > @@ -498,7 +498,7 @@ void arch_scale_freq_tick(void) > */ > #define MAX_SAMPLE_AGE ((unsigned long)HZ / 50) > > -unsigned int arch_freq_get_on_cpu(int cpu) > +int arch_freq_get_on_cpu(int cpu) > { > struct aperfmperf *s = per_cpu_ptr(&cpu_samples, cpu); > unsigned int seq, freq; > diff --git a/arch/x86/kernel/cpu/proc.c b/arch/x86/kernel/cpu/proc.c > index 41ed01f46bd9..d79f5845a463 100644 > --- a/arch/x86/kernel/cpu/proc.c > +++ b/arch/x86/kernel/cpu/proc.c > @@ -86,9 +86,12 @@ static int show_cpuinfo(struct seq_file *m, void *v) > seq_printf(m, "microcode\t: 0x%x\n", c->microcode); > > if (cpu_has(c, X86_FEATURE_TSC)) { > - unsigned int freq = arch_freq_get_on_cpu(cpu); > + int freq = arch_freq_get_on_cpu(cpu); > > - seq_printf(m, "cpu MHz\t\t: %u.%03u\n", freq / 1000, (freq % 1000)); > + if (freq <= 0) > + seq_puts(m, "cpu MHz\t\t: Unknown\n"); > + else > + seq_printf(m, "cpu MHz\t\t: %u.%03u\n", freq / 1000, (freq % 1000)); > } > > /* Cache size */ > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c > index 418236fef172..6f45684483c4 100644 > --- a/drivers/cpufreq/cpufreq.c > +++ b/drivers/cpufreq/cpufreq.c > @@ -728,18 +728,18 @@ show_one(cpuinfo_transition_latency, cpuinfo.transition_latency); > show_one(scaling_min_freq, min); > show_one(scaling_max_freq, max); > > -__weak unsigned int arch_freq_get_on_cpu(int cpu) > +__weak int arch_freq_get_on_cpu(int cpu) > { > - return 0; > + return -EOPNOTSUPP; > } > > static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf) > { > ssize_t ret; > - unsigned int freq; > + int freq; > > freq = arch_freq_get_on_cpu(policy->cpu); > - if (freq) > + if (freq > 0) > ret = sysfs_emit(buf, "%u\n", freq); > else if (cpufreq_driver->setpolicy && cpufreq_driver->get) > ret = sysfs_emit(buf, "%u\n", cpufreq_driver->get(policy->cpu)); > diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h > index 7fe0981a7e46..02fd4746231d 100644 > --- a/include/linux/cpufreq.h > +++ b/include/linux/cpufreq.h > @@ -1184,7 +1184,7 @@ static inline int of_perf_domain_get_sharing_cpumask(int pcpu, const char *list_ > } > #endif > > -extern unsigned int arch_freq_get_on_cpu(int cpu); > +extern int arch_freq_get_on_cpu(int cpu); > > #ifndef arch_set_freq_scale > static __always_inline Looks good to me. Reviewed-by: Prasanna Kumar T S M