[1/4] arm64: topology: Implement basic CPU topology support

Message ID	1392037324-5069-1-git-send-email-broonie@kernel.org (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org> From: Mark Brown <broonie@kernel.org> To: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will.deacon@arm.com>, Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Date: Mon, 10 Feb 2014 13:02:01 +0000 Message-Id: <1392037324-5069-1-git-send-email-broonie@kernel.org> Subject: [PATCH 1/4] arm64: topology: Implement basic CPU topology support Cc: linaro-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org, Mark Brown <broonie@linaro.org> Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" <linux-arm-kernel-bounces@lists.infradead.org> Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 27bbcfc7202a..fea7b477676b 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -164,6 +164,30 @@ config SMP If you don't know what to do here, say N. +config CPU_TOPOLOGY + bool "Support CPU topology definition" + depends on SMP + default y + help + Support CPU topology definition, based on configuration + provided by the firmware. + +config SCHED_MC + bool "Multi-core scheduler support" + depends on CPU_TOPOLOGY + help + Multi-core scheduler support improves the CPU scheduler's decision + making when dealing with multi-core CPU chips at a cost of slightly + increased overhead in some places. If unsure say N here. + +config SCHED_SMT + bool "SMT scheduler support" + depends on CPU_TOPOLOGY + help + Improves the CPU scheduler's decision making when dealing with + MultiThreading at a cost of slightly increased overhead in some + places. If unsure say N here. + config NR_CPUS int "Maximum number of CPUs (2-32)" range 2 32 diff --git a/arch/arm64/include/asm/topology.h b/arch/arm64/include/asm/topology.h new file mode 100644 index 000000000000..c8a47e8f452b --- /dev/null +++ b/arch/arm64/include/asm/topology.h @@ -0,0 +1,39 @@ +#ifndef __ASM_TOPOLOGY_H +#define __ASM_TOPOLOGY_H + +#ifdef CONFIG_CPU_TOPOLOGY + +#include <linux/cpumask.h> + +struct cpu_topology { + int thread_id; + int core_id; + int cluster_id; + cpumask_t thread_sibling; + cpumask_t core_sibling; +}; + +extern struct cpu_topology cpu_topology[NR_CPUS]; + +#define topology_physical_package_id(cpu) (cpu_topology[cpu].cluster_id) +#define topology_core_id(cpu) (cpu_topology[cpu].core_id) +#define topology_core_cpumask(cpu) (&cpu_topology[cpu].core_sibling) +#define topology_thread_cpumask(cpu) (&cpu_topology[cpu].thread_sibling) + +#define mc_capable() (cpu_topology[0].cluster_id != -1) +#define smt_capable() (cpu_topology[0].thread_id != -1) + +void init_cpu_topology(void); +void store_cpu_topology(unsigned int cpuid); +const struct cpumask *cpu_coregroup_mask(int cpu); + +#else + +static inline void init_cpu_topology(void) { } +static inline void store_cpu_topology(unsigned int cpuid) { } + +#endif + +#include <asm-generic/topology.h> + +#endif /* _ASM_ARM_TOPOLOGY_H */ diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile index 2d4554b13410..252b62181532 100644 --- a/arch/arm64/kernel/Makefile +++ b/arch/arm64/kernel/Makefile @@ -20,6 +20,7 @@ arm64-obj-$(CONFIG_HAVE_HW_BREAKPOINT)+= hw_breakpoint.o arm64-obj-$(CONFIG_EARLY_PRINTK) += early_printk.o arm64-obj-$(CONFIG_ARM64_CPU_SUSPEND) += sleep.o suspend.o arm64-obj-$(CONFIG_JUMP_LABEL) += jump_label.o +arm64-obj-$(CONFIG_CPU_TOPOLOGY) += topology.o obj-y += $(arm64-obj-y) vdso/ obj-m += $(arm64-obj-m) diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index 7cfb92a4ab66..9660750f34ba 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -114,6 +114,11 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle) return ret; } +static void smp_store_cpu_info(unsigned int cpuid) +{ + store_cpu_topology(cpuid); +} + /* * This is the secondary CPU boot entry. We're using this CPUs * idle thread stack, but a set of temporary page tables. @@ -152,6 +157,8 @@ asmlinkage void secondary_start_kernel(void) */ notify_cpu_starting(cpu); + smp_store_cpu_info(cpu); + /* * OK, now it's safe to let the boot CPU continue. Wait for * the CPU migration code to notice that the CPU is online @@ -390,6 +397,10 @@ void __init smp_prepare_cpus(unsigned int max_cpus) int err; unsigned int cpu, ncores = num_possible_cpus(); + init_cpu_topology(); + + smp_store_cpu_info(smp_processor_id()); + /* * are we trying to boot more cores than exist? */ diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c new file mode 100644 index 000000000000..a6d4ed2d69c0 --- /dev/null +++ b/arch/arm64/kernel/topology.c @@ -0,0 +1,91 @@ +/* + * arch/arm64/kernel/topology.c + * + * Copyright (C) 2011,2013 Linaro Limited. + * + * Based on the arm32 version written by Vincent Guittot in turn based on + * arch/sh/kernel/topology.c + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ + +#include <linux/cpu.h> +#include <linux/cpumask.h> +#include <linux/init.h> +#include <linux/percpu.h> +#include <linux/node.h> +#include <linux/nodemask.h> +#include <linux/sched.h> + +#include <asm/topology.h> + +/* + * cpu topology table + */ +struct cpu_topology cpu_topology[NR_CPUS]; +EXPORT_SYMBOL_GPL(cpu_topology); + +const struct cpumask *cpu_coregroup_mask(int cpu) +{ + return &cpu_topology[cpu].core_sibling; +} + +static void update_siblings_masks(unsigned int cpuid) +{ + struct cpu_topology *cpu_topo, *cpuid_topo = &cpu_topology[cpuid]; + int cpu; + + /* update core and thread sibling masks */ + for_each_possible_cpu(cpu) { + cpu_topo = &cpu_topology[cpu]; + + if (cpuid_topo->cluster_id != cpu_topo->cluster_id) + continue; + + cpumask_set_cpu(cpuid, &cpu_topo->core_sibling); + if (cpu != cpuid) + cpumask_set_cpu(cpu, &cpuid_topo->core_sibling); + + if (cpuid_topo->core_id != cpu_topo->core_id) + continue; + + cpumask_set_cpu(cpuid, &cpu_topo->thread_sibling); + if (cpu != cpuid) + cpumask_set_cpu(cpu, &cpuid_topo->thread_sibling); + } + smp_wmb(); +} + +void store_cpu_topology(unsigned int cpuid) +{ + struct cpu_topology *cpuid_topo = &cpu_topology[cpuid]; + + /* DT should have been parsed by the time we get here */ + if (cpuid_topo->core_id == -1) + pr_info("CPU%u: No topology information configured\n", cpuid); + else + update_siblings_masks(cpuid); +} + +/* + * init_cpu_topology is called at boot when only one cpu is running + * which prevent simultaneous write access to cpu_topology array + */ +void __init init_cpu_topology(void) +{ + unsigned int cpu; + + /* init core mask and power*/ + for_each_possible_cpu(cpu) { + struct cpu_topology *cpu_topo = &cpu_topology[cpu]; + + cpu_topo->thread_id = -1; + cpu_topo->core_id = -1; + cpu_topo->cluster_id = -1; + cpumask_clear(&cpu_topo->core_sibling); + cpumask_clear(&cpu_topo->thread_sibling); + } + smp_wmb(); +}

[1/4] arm64: topology: Implement basic CPU topology support

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