From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933044AbcCJMHp (ORCPT ); Thu, 10 Mar 2016 07:07:45 -0500 Received: from www.linutronix.de ([62.245.132.108]:60818 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753798AbcCJMGF (ORCPT ); Thu, 10 Mar 2016 07:06:05 -0500 Message-Id: <20160310120025.502222097@linutronix.de> User-Agent: quilt/0.63-1 Date: Thu, 10 Mar 2016 12:04:42 -0000 From: Thomas Gleixner To: LKML Cc: Peter Zijlstra , Ingo Molnar , rt@linutronix.de Subject: [patch 12/15] sched/hotplug: Move migration CPU_DYING to sched_cpu_dying() References: <20160310115406.940706476@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Disposition: inline; filename=sched_hotplug__Move_migration_CPU_DYING_to_sched_cpu_dying__.patch X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001,URIBL_BLOCKED=0.001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Remove the hotplug notifier and make it an explicit state. Signed-off-by: Thomas Gleixner --- include/linux/cpu.h | 2 - include/linux/sched.h | 1 kernel/cpu.c | 2 - kernel/sched/core.c | 70 ++++++++++++++------------------------------------ 4 files changed, 22 insertions(+), 53 deletions(-) --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -59,9 +59,7 @@ struct notifier_block; * CPU notifier priorities. */ enum { - /* migration should happen before other stuff but after perf */ CPU_PRI_PERF = 20, - CPU_PRI_MIGRATION = 10, /* bring up workqueues before normal notifiers and down after */ CPU_PRI_WORKQUEUE_UP = 5, --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -374,6 +374,7 @@ 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 int sched_cpu_dying(unsigned int cpu); extern int sched_cpu_activate(unsigned int cpu); extern int sched_cpu_deactivate(unsigned int cpu); --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -1204,7 +1204,7 @@ static struct cpuhp_step cpuhp_ap_states [CPUHP_AP_SCHED_STARTING] = { .name = "sched:starting", .startup = sched_cpu_starting, - .teardown = NULL, + .teardown = sched_cpu_dying, }, /* * Low level startup/teardown notifiers. Run with interrupts --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5649,51 +5649,6 @@ static void set_rq_offline(struct rq *rq } } -/* - * migration_call - callback that gets triggered when a CPU is added. - * Here we can start up the necessary migration thread for the new CPU. - */ -static int -migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) -{ - int cpu = (long)hcpu; - unsigned long flags; - struct rq *rq = cpu_rq(cpu); - - switch (action & ~CPU_TASKS_FROZEN) { - -#ifdef CONFIG_HOTPLUG_CPU - case CPU_DYING: - sched_ttwu_pending(); - /* Update our root-domain */ - raw_spin_lock_irqsave(&rq->lock, flags); - if (rq->rd) { - BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); - set_rq_offline(rq); - } - migrate_tasks(rq); - BUG_ON(rq->nr_running != 1); /* the migration thread */ - raw_spin_unlock_irqrestore(&rq->lock, flags); - calc_load_migrate(rq); - break; -#endif - } - - update_max_interval(); - - return NOTIFY_OK; -} - -/* - * Register at high priority so that task migration (migrate_all_tasks) - * happens before everything else. This has to be lower priority than - * the notifier in the perf_event subsystem, though. - */ -static struct notifier_block migration_notifier = { - .notifier_call = migration_call, - .priority = CPU_PRI_MIGRATION, -}; - static void set_cpu_rq_start_time(unsigned int cpu) { struct rq *rq = cpu_rq(cpu); @@ -7391,6 +7346,26 @@ int sched_cpu_starting(unsigned int cpu) return 0; } +int sched_cpu_dying(unsigned int cpu) +{ + struct rq *rq = cpu_rq(cpu); + unsigned long flags; + + /* Handle pending wakeups and then migrate everything off */ + sched_ttwu_pending(); + raw_spin_lock_irqsave(&rq->lock, flags); + if (rq->rd) { + BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); + set_rq_offline(rq); + } + migrate_tasks(rq); + BUG_ON(rq->nr_running != 1); + raw_spin_unlock_irqrestore(&rq->lock, flags); + calc_load_migrate(rq); + update_max_interval(); + return 0; +} + void __init sched_init_smp(void) { cpumask_var_t non_isolated_cpus; @@ -7427,12 +7402,7 @@ void __init sched_init_smp(void) static int __init migration_init(void) { - void *cpu = (void *)(long)smp_processor_id(); - sched_rq_cpu_starting(smp_processor_id()); - migration_call(&migration_notifier, CPU_ONLINE, cpu); - register_cpu_notifier(&migration_notifier); - return 0; } early_initcall(migration_init);