Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965025AbcJQPs1 (ORCPT ); Mon, 17 Oct 2016 11:48:27 -0400 Received: from foss.arm.com ([217.140.101.70]:36780 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935293AbcJQPrz (ORCPT ); Mon, 17 Oct 2016 11:47:55 -0400 From: Juri Lelli To: linux-kernel@vger.kernel.org Cc: linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, peterz@infradead.org, vincent.guittot@linaro.org, robh+dt@kernel.org, mark.rutland@arm.com, linux@arm.linux.org.uk, sudeep.holla@arm.com, lorenzo.pieralisi@arm.com, catalin.marinas@arm.com, will.deacon@arm.com, morten.rasmussen@arm.com, dietmar.eggemann@arm.com, juri.lelli@arm.com, broonie@kernel.org Subject: [PATCH v7 REPOST 4/9] arm64: parse cpu capacity-dmips-mhz from DT Date: Mon, 17 Oct 2016 16:46:45 +0100 Message-Id: <20161017154650.18779-5-juri.lelli@arm.com> X-Mailer: git-send-email 2.10.0 In-Reply-To: <20161017154650.18779-1-juri.lelli@arm.com> References: <20161017154650.18779-1-juri.lelli@arm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6634 Lines: 233 With the introduction of cpu capacity-dmips-mhz bindings, CPU capacities can now be calculated from values extracted from DT and information coming from cpufreq. Add parsing of DT information at boot time, and complement it with cpufreq information. Also, store such information using per CPU variables, as we do for arm. Caveat: the information provided by this patch will start to be used in the future. We need to #define arch_scale_cpu_capacity to something provided in arch, so that scheduler's default implementation (which gets used if arch_scale_cpu_capacity is not defined) is overwritten. Cc: Catalin Marinas Cc: Will Deacon Cc: Mark Brown Cc: Sudeep Holla Signed-off-by: Juri Lelli Acked-by: Vincent Guittot --- Changes from v1: - normalize w.r.t. highest capacity found in DT - bailout conditions (all-or-nothing) Changes from v4: - parsing modified to reflect change in binding (capacity-dmips-mhz) Changes from v5: - allocate raw_capacity array with kcalloc() - pr_err() only for partial capacity information Changes from v6: - use cpuinfo.max_freq instead of policy->max - add delayed work to unregister cpufreq notifier --- arch/arm64/kernel/topology.c | 159 ++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 158 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c index 694f6deedbab..b75b0ba2e113 100644 --- a/arch/arm64/kernel/topology.c +++ b/arch/arm64/kernel/topology.c @@ -19,10 +19,162 @@ #include #include #include +#include +#include #include #include +static DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE; + +unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu) +{ + return per_cpu(cpu_scale, cpu); +} + +static void set_capacity_scale(unsigned int cpu, unsigned long capacity) +{ + per_cpu(cpu_scale, cpu) = capacity; +} + +static u32 capacity_scale; +static u32 *raw_capacity; +static bool cap_parsing_failed; + +static void __init parse_cpu_capacity(struct device_node *cpu_node, int cpu) +{ + int ret; + u32 cpu_capacity; + + if (cap_parsing_failed) + return; + + ret = of_property_read_u32(cpu_node, + "capacity-dmips-mhz", + &cpu_capacity); + if (!ret) { + if (!raw_capacity) { + raw_capacity = kcalloc(num_possible_cpus(), + sizeof(*raw_capacity), + GFP_KERNEL); + if (!raw_capacity) { + pr_err("cpu_capacity: failed to allocate memory for raw capacities\n"); + cap_parsing_failed = true; + return; + } + } + capacity_scale = max(cpu_capacity, capacity_scale); + raw_capacity[cpu] = cpu_capacity; + pr_debug("cpu_capacity: %s cpu_capacity=%u (raw)\n", + cpu_node->full_name, raw_capacity[cpu]); + } else { + if (raw_capacity) { + pr_err("cpu_capacity: missing %s raw capacity\n", + cpu_node->full_name); + pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n"); + } + cap_parsing_failed = true; + kfree(raw_capacity); + } +} + +static void normalize_cpu_capacity(void) +{ + u64 capacity; + int cpu; + + if (!raw_capacity || cap_parsing_failed) + return; + + pr_debug("cpu_capacity: capacity_scale=%u\n", capacity_scale); + for_each_possible_cpu(cpu) { + pr_debug("cpu_capacity: cpu=%d raw_capacity=%u\n", + cpu, raw_capacity[cpu]); + capacity = (raw_capacity[cpu] << SCHED_CAPACITY_SHIFT) + / capacity_scale; + set_capacity_scale(cpu, capacity); + pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n", + cpu, arch_scale_cpu_capacity(NULL, cpu)); + } +} + +#ifdef CONFIG_CPU_FREQ +static cpumask_var_t cpus_to_visit; +static bool cap_parsing_done; +static void parsing_done_workfn(struct work_struct *work); +static DECLARE_WORK(parsing_done_work, parsing_done_workfn); + +static int +init_cpu_capacity_callback(struct notifier_block *nb, + unsigned long val, + void *data) +{ + struct cpufreq_policy *policy = data; + int cpu; + + if (cap_parsing_failed || cap_parsing_done) + return 0; + + switch (val) { + case CPUFREQ_NOTIFY: + pr_debug("cpu_capacity: init cpu capacity for CPUs [%*pbl] (to_visit=%*pbl)\n", + cpumask_pr_args(policy->related_cpus), + cpumask_pr_args(cpus_to_visit)); + cpumask_andnot(cpus_to_visit, + cpus_to_visit, + policy->related_cpus); + for_each_cpu(cpu, policy->related_cpus) { + raw_capacity[cpu] = arch_scale_cpu_capacity(NULL, cpu) * + policy->cpuinfo.max_freq / 1000UL; + capacity_scale = max(raw_capacity[cpu], capacity_scale); + } + if (cpumask_empty(cpus_to_visit)) { + normalize_cpu_capacity(); + kfree(raw_capacity); + pr_debug("cpu_capacity: parsing done\n"); + cap_parsing_done = true; + schedule_work(&parsing_done_work); + } + } + return 0; +} + +static struct notifier_block init_cpu_capacity_notifier = { + .notifier_call = init_cpu_capacity_callback, +}; + +static int __init register_cpufreq_notifier(void) +{ + if (cap_parsing_failed) + return -EINVAL; + + if (!alloc_cpumask_var(&cpus_to_visit, GFP_KERNEL)) { + pr_err("cpu_capacity: failed to allocate memory for cpus_to_visit\n"); + return -ENOMEM; + } + cpumask_copy(cpus_to_visit, cpu_possible_mask); + + return cpufreq_register_notifier(&init_cpu_capacity_notifier, + CPUFREQ_POLICY_NOTIFIER); +} +core_initcall(register_cpufreq_notifier); + +static void parsing_done_workfn(struct work_struct *work) +{ + cpufreq_unregister_notifier(&init_cpu_capacity_notifier, + CPUFREQ_POLICY_NOTIFIER); +} + +#else +static int __init free_raw_capacity(void) +{ + kfree(raw_capacity); + + return 0; +} +core_initcall(free_raw_capacity); +#endif + static int __init get_cpu_for_node(struct device_node *node) { struct device_node *cpu_node; @@ -34,6 +186,7 @@ static int __init get_cpu_for_node(struct device_node *node) for_each_possible_cpu(cpu) { if (of_get_cpu_node(cpu, NULL) == cpu_node) { + parse_cpu_capacity(cpu_node, cpu); of_node_put(cpu_node); return cpu; } @@ -178,13 +331,17 @@ static int __init parse_dt_topology(void) * cluster with restricted subnodes. */ map = of_get_child_by_name(cn, "cpu-map"); - if (!map) + if (!map) { + cap_parsing_failed = true; goto out; + } ret = parse_cluster(map, 0); if (ret != 0) goto out_map; + normalize_cpu_capacity(); + /* * Check that all cores are in the topology; the SMP code will * only mark cores described in the DT as possible. -- 2.10.0