From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id D2D8D13AA46 for ; Wed, 17 Apr 2024 09:39:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713346744; cv=none; b=OmUMKVYsDHxCTyBWFv3tsiF8l01XMeEistoL2GgBqFjzf5G/4z5MPwycrMiHLg1J6KgDvyBJaj6XAxXHNH4bQNqWl3Z5ZZoB3C4YDxOxQ0k0mmkVex+3E/KpweBDW4NR6qmv8eXwso4m7Xe1HtETjP2dVuFsDkmQh4hcvguMNjk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713346744; c=relaxed/simple; bh=LE515nvwvBtP8gvCOVvIKqxcZH+UImq3DBTaJCX47A4=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=udXTDRX0JJTNDCmpbtA5gOWGUX+Tdsq+uB2lMudJSZ1iXUPulplgckiyYaGJWJZn987P3CiOM4NeDqVdcNMCQep7slcH8jmu0I3dI8y43bLlpcWI/qNhMn05XEGUP0MBMqA16dwaqIXCKVMjFGHzML7PX9SJT50VzoyhUXnjuEA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 20C32DA7; Wed, 17 Apr 2024 02:39:30 -0700 (PDT) Received: from e125905.cambridge.arm.com (e125905.cambridge.arm.com [10.1.194.73]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 71D283F64C; Wed, 17 Apr 2024 02:39:00 -0700 (PDT) From: Beata Michalska To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, ionela.voinescu@arm.com, vanshikonda@os.amperecomputing.com Cc: sudeep.holla@arm.com, will@kernel.org, catalin.marinas@arm.com, vincent.guittot@linaro.org, sumitg@nvidia.com, yang@os.amperecomputing.com, lihuisong@huawei.com, viresh.kumar@linaro.org Subject: [PATCH v5 1/5] arch_topology: init capacity_freq_ref to 0 Date: Wed, 17 Apr 2024 10:38:44 +0100 Message-Id: <20240417093848.1555462-2-beata.michalska@arm.com> In-Reply-To: <20240417093848.1555462-1-beata.michalska@arm.com> References: <20240417093848.1555462-1-beata.michalska@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Ionela Voinescu It's useful to have capacity_freq_ref initialized to 0 for users of arch_scale_freq_ref() to detect when capacity_freq_ref was not yet set. The only scenario affected by this change in the init value is when a cpufreq driver is never loaded. As a result, the only setter of a cpu scale factor remains the call of topology_normalize_cpu_scale() from parse_dt_topology(). There we cannot use the value 0 of capacity_freq_ref so we have to compensate for its uninitialized state. Signed-off-by: Ionela Voinescu Signed-off-by: Beata Michalska Reviewed-by: Vincent Guittot --- drivers/base/arch_topology.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c index 024b78a0cfc1..7d4c92cd2bad 100644 --- a/drivers/base/arch_topology.c +++ b/drivers/base/arch_topology.c @@ -27,7 +27,7 @@ static DEFINE_PER_CPU(struct scale_freq_data __rcu *, sft_data); static struct cpumask scale_freq_counters_mask; static bool scale_freq_invariant; -DEFINE_PER_CPU(unsigned long, capacity_freq_ref) = 1; +DEFINE_PER_CPU(unsigned long, capacity_freq_ref) = 0; EXPORT_PER_CPU_SYMBOL_GPL(capacity_freq_ref); static bool supports_scale_freq_counters(const struct cpumask *cpus) @@ -292,13 +292,15 @@ void topology_normalize_cpu_scale(void) capacity_scale = 1; for_each_possible_cpu(cpu) { - capacity = raw_capacity[cpu] * per_cpu(capacity_freq_ref, cpu); + capacity = raw_capacity[cpu] * + (per_cpu(capacity_freq_ref, cpu) ?: 1); capacity_scale = max(capacity, capacity_scale); } pr_debug("cpu_capacity: capacity_scale=%llu\n", capacity_scale); for_each_possible_cpu(cpu) { - capacity = raw_capacity[cpu] * per_cpu(capacity_freq_ref, cpu); + capacity = raw_capacity[cpu] * + (per_cpu(capacity_freq_ref, cpu) ?: 1); capacity = div64_u64(capacity << SCHED_CAPACITY_SHIFT, capacity_scale); topology_set_cpu_scale(cpu, capacity); -- 2.25.1