From 9cf7243d5d83d27aca47f842107bfa02b5f11d16 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 10 Mar 2016 12:54:09 +0100 Subject: [PATCH] sched: Make set_cpu_rq_start_time() a built in hotplug state Start distangling the maze of hotplug notifiers in the scheduler. Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra Cc: rt@linutronix.de Signed-off-by: Thomas Gleixner --- include/linux/cpuhotplug.h | 1 + include/linux/sched.h | 1 + kernel/cpu.c | 6 ++++++ kernel/sched/core.c | 16 +++++++++------- 4 files changed, 17 insertions(+), 7 deletions(-) diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h index 5d68e15..99fd1d2 100644 --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h @@ -8,6 +8,7 @@ enum cpuhp_state { CPUHP_BRINGUP_CPU, CPUHP_AP_IDLE_DEAD, CPUHP_AP_OFFLINE, + CPUHP_AP_SCHED_STARTING, CPUHP_AP_NOTIFY_STARTING, CPUHP_AP_ONLINE, CPUHP_TEARDOWN_CPU, diff --git a/include/linux/sched.h b/include/linux/sched.h index 52c4847..39597d0 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -372,6 +372,7 @@ extern void cpu_init (void); extern void trap_init(void); extern void update_process_times(int user); extern void scheduler_tick(void); +extern int sched_cpu_starting(unsigned int cpu); extern void sched_show_task(struct task_struct *p); diff --git a/kernel/cpu.c b/kernel/cpu.c index 3e3f6e4..f46d02b 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -1236,6 +1236,12 @@ static struct cpuhp_step cpuhp_ap_states[] = { .name = "ap:offline", .cant_stop = true, }, + /* First state is scheduler control. Interrupts are disabled */ + [CPUHP_AP_SCHED_STARTING] = { + .name = "sched:starting", + .startup = sched_cpu_starting, + .teardown = NULL, + }, /* * Low level startup/teardown notifiers. Run with interrupts * disabled. Will be removed once the notifiers are converted to diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 8bfd7d4..4df9aaa 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5473,10 +5473,10 @@ static struct notifier_block migration_notifier = { .priority = CPU_PRI_MIGRATION, }; -static void set_cpu_rq_start_time(void) +static void set_cpu_rq_start_time(unsigned int cpu) { - int cpu = smp_processor_id(); struct rq *rq = cpu_rq(cpu); + rq->age_stamp = sched_clock_cpu(cpu); } @@ -5486,10 +5486,6 @@ static int sched_cpu_active(struct notifier_block *nfb, int cpu = (long)hcpu; switch (action & ~CPU_TASKS_FROZEN) { - case CPU_STARTING: - set_cpu_rq_start_time(); - return NOTIFY_OK; - case CPU_DOWN_FAILED: set_cpu_active(cpu, true); return NOTIFY_OK; @@ -5511,6 +5507,12 @@ static int sched_cpu_inactive(struct notifier_block *nfb, } } +int sched_cpu_starting(unsigned int cpu) +{ + set_cpu_rq_start_time(cpu); + return 0; +} + static int __init migration_init(void) { void *cpu = (void *)(long)smp_processor_id(); @@ -7426,7 +7428,7 @@ void __init sched_init(void) if (cpu_isolated_map == NULL) zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT); idle_thread_set_boot_cpu(); - set_cpu_rq_start_time(); + set_cpu_rq_start_time(smp_processor_id()); #endif init_sched_fair_class(); -- 2.7.4