From patchwork Thu Nov 3 05:40:18 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Juri Lelli X-Patchwork-Id: 9410283 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 8C8A760573 for ; Thu, 3 Nov 2016 05:41:49 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7DC682A641 for ; Thu, 3 Nov 2016 05:41:49 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 71C042A765; Thu, 3 Nov 2016 05:41:49 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=unavailable version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 03F602A641 for ; Thu, 3 Nov 2016 05:41:49 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1c2AlG-0003F1-25; Thu, 03 Nov 2016 05:40:26 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1c2AlC-00023b-1q for linux-arm-kernel@lists.infradead.org; Thu, 03 Nov 2016 05:40:22 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id BC0ED16; Wed, 2 Nov 2016 22:40:01 -0700 (PDT) Received: from e106622-lin (e106622-lin.cambridge.arm.com [10.1.211.43]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5B67A3F591; Wed, 2 Nov 2016 22:39:59 -0700 (PDT) Date: Thu, 3 Nov 2016 05:40:18 +0000 From: Juri Lelli To: linux-kernel@vger.kernel.org Subject: Re: [PATCH v7 REPOST 9/9] arm64: add sysfs cpu_capacity attribute Message-ID: <20161103054018.GC16920@e106622-lin> References: <20161017154650.18779-1-juri.lelli@arm.com> <20161017154650.18779-10-juri.lelli@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20161017154650.18779-10-juri.lelli@arm.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20161102_224022_153161_7AA1D7B3 X-CRM114-Status: GOOD ( 17.94 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, devicetree@vger.kernel.org, lorenzo.pieralisi@arm.com, vincent.guittot@linaro.org, linux-pm@vger.kernel.org, peterz@infradead.org, catalin.marinas@arm.com, broonie@kernel.org, will.deacon@arm.com, dietmar.eggemann@arm.com, robh+dt@kernel.org, sudeep.holla@arm.com, linux@arm.linux.org.uk, morten.rasmussen@arm.com, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP Hi, small update to be in sync with Russell's comments on arm correspoding patch. On 17/10/16 16:46, Juri Lelli wrote: > Add a sysfs cpu_capacity attribute with which it is possible to read and > write (thus over-writing default values) CPUs capacity. This might be > useful in situations where values needs changing after boot. > > The new attribute shows up as: > > /sys/devices/system/cpu/cpu*/cpu_capacity > > Cc: Catalin Marinas > Cc: Will Deacon > Cc: Mark Brown > Cc: Sudeep Holla > Signed-off-by: Juri Lelli > --- > > Changes from v5: > - add mutex to protect cpu_scale (as pointed out by Morten off-line) --->8--- From 17684f3db6d74342da424997badcb3714a1a9e63 Mon Sep 17 00:00:00 2001 From: Juri Lelli Date: Wed, 14 Oct 2015 12:02:05 +0100 Subject: [PATCH v7.1 9/9] arm64: add sysfs cpu_capacity attribute Add a sysfs cpu_capacity attribute with which it is possible to read and write (thus over-writing default values) CPUs capacity. This might be useful in situations where values needs changing after boot. The new attribute shows up as: /sys/devices/system/cpu/cpu*/cpu_capacity Cc: Catalin Marinas Cc: Will Deacon Cc: Mark Brown Cc: Sudeep Holla Signed-off-by: Juri Lelli --- Changes from v5: - add mutex to protect cpu_scale (as pointed out by Morten off-line) Changes from v7: - include files moved at top of file - show_cpu_capacity simplified to less lines of code - unnecessary cast removed in store_cpu_capacity - use DEVICE_ATTR_RW() instead of DEVICE_ATTR() - use subsys_initcall instead of late_initcall --- arch/arm64/kernel/topology.c | 64 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 64 insertions(+) diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c index b75b0ba2e113..23e9e13bd2aa 100644 --- a/arch/arm64/kernel/topology.c +++ b/arch/arm64/kernel/topology.c @@ -20,12 +20,15 @@ #include #include #include +#include #include +#include #include #include static DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE; +static DEFINE_MUTEX(cpu_scale_mutex); unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu) { @@ -37,6 +40,65 @@ static void set_capacity_scale(unsigned int cpu, unsigned long capacity) per_cpu(cpu_scale, cpu) = capacity; } +#ifdef CONFIG_PROC_SYSCTL +static ssize_t cpu_capacity_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct cpu *cpu = container_of(dev, struct cpu, dev); + + return sprintf(buf, "%lu\n", + arch_scale_cpu_capacity(NULL, cpu->dev.id)); +} + +static ssize_t cpu_capacity_store(struct device *dev, + struct device_attribute *attr, + const char *buf, + size_t count) +{ + struct cpu *cpu = container_of(dev, struct cpu, dev); + int this_cpu = cpu->dev.id, i; + unsigned long new_capacity; + ssize_t ret; + + if (count) { + ret = kstrtoul(buf, 0, &new_capacity); + if (ret) + return ret; + if (new_capacity > SCHED_CAPACITY_SCALE) + return -EINVAL; + + mutex_lock(&cpu_scale_mutex); + for_each_cpu(i, &cpu_topology[this_cpu].core_sibling) + set_capacity_scale(i, new_capacity); + mutex_unlock(&cpu_scale_mutex); + } + + return count; +} + +static DEVICE_ATTR_RW(cpu_capacity); + +static int register_cpu_capacity_sysctl(void) +{ + int i; + struct device *cpu; + + for_each_possible_cpu(i) { + cpu = get_cpu_device(i); + if (!cpu) { + pr_err("%s: too early to get CPU%d device!\n", + __func__, i); + continue; + } + device_create_file(cpu, &dev_attr_cpu_capacity); + } + + return 0; +} +subsys_initcall(register_cpu_capacity_sysctl); +#endif + static u32 capacity_scale; static u32 *raw_capacity; static bool cap_parsing_failed; @@ -87,6 +149,7 @@ static void normalize_cpu_capacity(void) return; pr_debug("cpu_capacity: capacity_scale=%u\n", capacity_scale); + mutex_lock(&cpu_scale_mutex); for_each_possible_cpu(cpu) { pr_debug("cpu_capacity: cpu=%d raw_capacity=%u\n", cpu, raw_capacity[cpu]); @@ -96,6 +159,7 @@ static void normalize_cpu_capacity(void) pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n", cpu, arch_scale_cpu_capacity(NULL, cpu)); } + mutex_unlock(&cpu_scale_mutex); } #ifdef CONFIG_CPU_FREQ