diff options
| -rw-r--r-- | include/linux/cpuhotplug.h | 2 | ||||
| -rw-r--r-- | include/linux/perf_event.h | 9 | ||||
| -rw-r--r-- | kernel/cpu.c | 11 | ||||
| -rw-r--r-- | kernel/events/core.c | 56 |
4 files changed, 32 insertions, 46 deletions
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h index d769ec9..067082e 100644 --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h @@ -4,6 +4,7 @@ enum cpuhp_state { CPUHP_OFFLINE, CPUHP_CREATE_THREADS, + CPUHP_PERF_PREPARE, CPUHP_NOTIFY_PREPARE, CPUHP_BRINGUP_CPU, CPUHP_AP_IDLE_DEAD, @@ -22,6 +23,7 @@ enum cpuhp_state { CPUHP_AP_ONLINE_IDLE, CPUHP_AP_SMPBOOT_THREADS, CPUHP_AP_X86_VDSO_VMA_ONLINE, + CPUHP_AP_PERF_ONLINE, CPUHP_AP_NOTIFY_ONLINE, CPUHP_AP_ONLINE_DYN, CPUHP_AP_ONLINE_DYN_END = CPUHP_AP_ONLINE_DYN + 30, diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 1a827ce..9abeb69 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1354,4 +1354,13 @@ _name##_show(struct device *dev, \ \ static struct device_attribute format_attr_##_name = __ATTR_RO(_name) +/* Performance counter hotplug functions */ +#ifdef CONFIG_PERF_EVENTS +int perf_event_init_cpu(unsigned int cpu); +int perf_event_exit_cpu(unsigned int cpu); +#else +#define perf_event_init_cpu NULL +#define perf_event_exit_cpu NULL +#endif + #endif /* _LINUX_PERF_EVENT_H */ diff --git a/kernel/cpu.c b/kernel/cpu.c index fe71ce4..3705d90 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -1180,6 +1180,11 @@ static struct cpuhp_step cpuhp_bp_states[] = { .teardown = NULL, .cant_stop = true, }, + [CPUHP_PERF_PREPARE] = { + .name = "perf prepare", + .startup = perf_event_init_cpu, + .teardown = perf_event_exit_cpu, + }, /* * Preparatory and dead notifiers. Will be replaced once the notifiers * are converted to states. @@ -1257,6 +1262,12 @@ static struct cpuhp_step cpuhp_ap_states[] = { .startup = smpboot_unpark_threads, .teardown = NULL, }, + [CPUHP_AP_PERF_ONLINE] = { + .name = "perf online", + .startup = perf_event_init_cpu, + .teardown = perf_event_exit_cpu, + }, + /* * Online/down_prepare notifiers. Will be removed once the notifiers * are converted to states. diff --git a/kernel/events/core.c b/kernel/events/core.c index 43d43a2d..f3ef1c2 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -10255,7 +10255,7 @@ static void __init perf_event_init_all_cpus(void) } } -static void perf_event_init_cpu(int cpu) +int perf_event_init_cpu(unsigned int cpu) { struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); @@ -10268,6 +10268,7 @@ static void perf_event_init_cpu(int cpu) rcu_assign_pointer(swhash->swevent_hlist, hlist); } mutex_unlock(&swhash->hlist_mutex); + return 0; } #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE @@ -10299,14 +10300,17 @@ static void perf_event_exit_cpu_context(int cpu) } srcu_read_unlock(&pmus_srcu, idx); } +#else + +static void perf_event_exit_cpu_context(int cpu) { } + +#endif -static void perf_event_exit_cpu(int cpu) +int perf_event_exit_cpu(unsigned int cpu) { perf_event_exit_cpu_context(cpu); + return 0; } -#else -static inline void perf_event_exit_cpu(int cpu) { } -#endif static int perf_reboot(struct notifier_block *notifier, unsigned long val, void *v) @@ -10328,46 +10332,6 @@ static struct notifier_block perf_reboot_notifier = { .priority = INT_MIN, }; -static int -perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) -{ - unsigned int cpu = (long)hcpu; - - switch (action & ~CPU_TASKS_FROZEN) { - - case CPU_UP_PREPARE: - /* - * This must be done before the CPU comes alive, because the - * moment we can run tasks we can encounter (software) events. - * - * Specifically, someone can have inherited events on kthreadd - * or a pre-existing worker thread that gets re-bound. - */ - perf_event_init_cpu(cpu); - break; - - case CPU_DOWN_PREPARE: - /* - * This must be done before the CPU dies because after that an - * active event might want to IPI the CPU and that'll not work - * so great for dead CPUs. - * - * XXX smp_call_function_single() return -ENXIO without a warn - * so we could possibly deal with this. - * - * This is safe against new events arriving because - * sys_perf_event_open() serializes against hotplug using - * get_online_cpus(). - */ - perf_event_exit_cpu(cpu); - break; - default: - break; - } - - return NOTIFY_OK; -} - void __init perf_event_init(void) { int ret; @@ -10380,7 +10344,7 @@ void __init perf_event_init(void) perf_pmu_register(&perf_cpu_clock, NULL, -1); perf_pmu_register(&perf_task_clock, NULL, -1); perf_tp_register(); - perf_cpu_notifier(perf_cpu_notify); + perf_event_init_cpu(smp_processor_id()); register_reboot_notifier(&perf_reboot_notifier); ret = init_hw_breakpoint(); |