From nobody Wed Dec 17 12:48:27 2025 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 9523757CAB for ; Mon, 3 Jun 2024 08:22:12 +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=1717402933; cv=none; b=F0pPWskCNB7ys+0oelMv0T99yNVkAMH5HoHBsfgbDyDxjuV2kiJoQ3lVlJIYiZ94I773ZNbvb2OXO5mBj03DLu1O68tGVWjvLIv27RKrXIc4odY48m2IkgFoT6MKHL4CdP2yOIQ7GOAokQvURWY/AMmsdKXJlquU/w01nFWfW1w= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717402933; c=relaxed/simple; bh=2eSMXYfYYs6HArv4V6/WQUuvgtIzkW1Gs3FiPPKAfJY=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=OC2SwPAxlvxcw1LukBwy3lLq4aPdsuqhZxflRzXKrwWbkRCAsoQgYkDrfhnMfVOUN9TzUS/KMhBufNxj8CYadFO968ACW6lMi6jaXzvZ3TXI/JCtND7ibYT2Hi2sYgKcxj7V58HG7vRN2NjGT8RZNnBrqRlp6rW0hyFdgJJxwCo= 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 4D70C1063; Mon, 3 Jun 2024 01:22:36 -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 4FDEC3F792; Mon, 3 Jun 2024 01:22:10 -0700 (PDT) From: Beata Michalska To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, ionela.voinescu@arm.com, sudeep.holla@arm.com, will@kernel.org, catalin.marinas@arm.com, vincent.guittot@linaro.org, vanshikonda@os.amperecomputing.com Cc: sumitg@nvidia.com, yang@os.amperecomputing.com, lihuisong@huawei.com, viresh.kumar@linaro.org, rafael@kernel.org Subject: [PATCH v6 1/4] arch_topology: init capacity_freq_ref to 0 Date: Mon, 3 Jun 2024 09:21:51 +0100 Message-Id: <20240603082154.3830591-2-beata.michalska@arm.com> In-Reply-To: <20240603082154.3830591-1-beata.michalska@arm.com> References: <20240603082154.3830591-1-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: quoted-printable Content-Type: text/plain; charset="utf-8" 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 Reviewed-by: Sudeep Holla --- 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 c66d070207a0..b8217ce9082c 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) =3D 1; +DEFINE_PER_CPU(unsigned long, capacity_freq_ref) =3D 0; EXPORT_PER_CPU_SYMBOL_GPL(capacity_freq_ref); =20 static bool supports_scale_freq_counters(const struct cpumask *cpus) @@ -292,13 +292,15 @@ void topology_normalize_cpu_scale(void) =20 capacity_scale =3D 1; for_each_possible_cpu(cpu) { - capacity =3D raw_capacity[cpu] * per_cpu(capacity_freq_ref, cpu); + capacity =3D raw_capacity[cpu] * + (per_cpu(capacity_freq_ref, cpu) ?: 1); capacity_scale =3D max(capacity, capacity_scale); } =20 pr_debug("cpu_capacity: capacity_scale=3D%llu\n", capacity_scale); for_each_possible_cpu(cpu) { - capacity =3D raw_capacity[cpu] * per_cpu(capacity_freq_ref, cpu); + capacity =3D raw_capacity[cpu] * + (per_cpu(capacity_freq_ref, cpu) ?: 1); capacity =3D div64_u64(capacity << SCHED_CAPACITY_SHIFT, capacity_scale); topology_set_cpu_scale(cpu, capacity); --=20 2.25.1