From fdc15a36d84eeb52f58b907f03fd8f77f5648235 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Wed, 13 Jul 2016 17:16:25 +0000 Subject: bus/arm-ccn: Convert to hotplug statemachine Install the callbacks via the state machine and let the core invoke the callbacks on the already online CPUs. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Anna-Maria Gleixner Cc: Arnd Bergmann Cc: Dan Carpenter Cc: Linus Torvalds Cc: Pawel Moll Cc: Peter Zijlstra Cc: Suzuki K Poulose Cc: Thomas Gleixner Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160713153334.768498577@linutronix.de Signed-off-by: Ingo Molnar --- drivers/bus/arm-ccn.c | 57 +++++++++++++++++++++++++-------------------------- 1 file changed, 28 insertions(+), 29 deletions(-) (limited to 'drivers/bus') diff --git a/drivers/bus/arm-ccn.c b/drivers/bus/arm-ccn.c index acc3eb542c74..97a9185af433 100644 --- a/drivers/bus/arm-ccn.c +++ b/drivers/bus/arm-ccn.c @@ -167,7 +167,7 @@ struct arm_ccn_dt { struct hrtimer hrtimer; cpumask_t cpu; - struct notifier_block cpu_nb; + struct list_head entry; struct pmu pmu; }; @@ -189,6 +189,8 @@ struct arm_ccn { struct arm_ccn_dt dt; }; +static DEFINE_MUTEX(arm_ccn_mutex); +static LIST_HEAD(arm_ccn_list); static int arm_ccn_node_to_xp(int node) { @@ -1171,30 +1173,27 @@ static enum hrtimer_restart arm_ccn_pmu_timer_handler(struct hrtimer *hrtimer) } -static int arm_ccn_pmu_cpu_notifier(struct notifier_block *nb, - unsigned long action, void *hcpu) +static int arm_ccn_pmu_offline_cpu(unsigned int cpu) { - struct arm_ccn_dt *dt = container_of(nb, struct arm_ccn_dt, cpu_nb); - struct arm_ccn *ccn = container_of(dt, struct arm_ccn, dt); - unsigned int cpu = (long)hcpu; /* for (long) see kernel/cpu.c */ + struct arm_ccn_dt *dt; unsigned int target; - switch (action & ~CPU_TASKS_FROZEN) { - case CPU_DOWN_PREPARE: + mutex_lock(&arm_ccn_mutex); + list_for_each_entry(dt, &arm_ccn_list, entry) { + struct arm_ccn *ccn = container_of(dt, struct arm_ccn, dt); + if (!cpumask_test_and_clear_cpu(cpu, &dt->cpu)) - break; + continue; target = cpumask_any_but(cpu_online_mask, cpu); if (target >= nr_cpu_ids) - break; + continue; perf_pmu_migrate_context(&dt->pmu, cpu, target); cpumask_set_cpu(target, &dt->cpu); if (ccn->irq) WARN_ON(irq_set_affinity_hint(ccn->irq, &dt->cpu) != 0); - default: - break; } - - return NOTIFY_OK; + mutex_unlock(&arm_ccn_mutex); + return 0; } @@ -1266,16 +1265,6 @@ static int arm_ccn_pmu_init(struct arm_ccn *ccn) /* Pick one CPU which we will use to collect data from CCN... */ cpumask_set_cpu(smp_processor_id(), &ccn->dt.cpu); - /* - * ... and change the selection when it goes offline. Priority is - * picked to have a chance to migrate events before perf is notified. - */ - ccn->dt.cpu_nb.notifier_call = arm_ccn_pmu_cpu_notifier; - ccn->dt.cpu_nb.priority = CPU_PRI_PERF + 1, - err = register_cpu_notifier(&ccn->dt.cpu_nb); - if (err) - goto error_cpu_notifier; - /* Also make sure that the overflow interrupt is handled by this CPU */ if (ccn->irq) { err = irq_set_affinity_hint(ccn->irq, &ccn->dt.cpu); @@ -1289,12 +1278,13 @@ static int arm_ccn_pmu_init(struct arm_ccn *ccn) if (err) goto error_pmu_register; + mutex_lock(&arm_ccn_mutex); + list_add(&ccn->dt.entry, &arm_ccn_list); + mutex_unlock(&arm_ccn_mutex); return 0; error_pmu_register: error_set_affinity: - unregister_cpu_notifier(&ccn->dt.cpu_nb); -error_cpu_notifier: ida_simple_remove(&arm_ccn_pmu_ida, ccn->dt.id); for (i = 0; i < ccn->num_xps; i++) writel(0, ccn->xp[i].base + CCN_XP_DT_CONTROL); @@ -1306,9 +1296,12 @@ static void arm_ccn_pmu_cleanup(struct arm_ccn *ccn) { int i; + mutex_lock(&arm_ccn_mutex); + list_del(&ccn->dt.entry); + mutex_unlock(&arm_ccn_mutex); + if (ccn->irq) irq_set_affinity_hint(ccn->irq, NULL); - unregister_cpu_notifier(&ccn->dt.cpu_nb); for (i = 0; i < ccn->num_xps; i++) writel(0, ccn->xp[i].base + CCN_XP_DT_CONTROL); writel(0, ccn->dt.base + CCN_DT_PMCR); @@ -1316,7 +1309,6 @@ static void arm_ccn_pmu_cleanup(struct arm_ccn *ccn) ida_simple_remove(&arm_ccn_pmu_ida, ccn->dt.id); } - static int arm_ccn_for_each_valid_region(struct arm_ccn *ccn, int (*callback)(struct arm_ccn *ccn, int region, void __iomem *base, u32 type, u32 id)) @@ -1533,7 +1525,13 @@ static struct platform_driver arm_ccn_driver = { static int __init arm_ccn_init(void) { - int i; + int i, ret; + + ret = cpuhp_setup_state_nocalls(CPUHP_AP_PERF_ARM_CCN_ONLINE, + "AP_PERF_ARM_CCN_ONLINE", NULL, + arm_ccn_pmu_offline_cpu); + if (ret) + return ret; for (i = 0; i < ARRAY_SIZE(arm_ccn_pmu_events); i++) arm_ccn_pmu_events_attrs[i] = &arm_ccn_pmu_events[i].attr.attr; @@ -1543,6 +1541,7 @@ static int __init arm_ccn_init(void) static void __exit arm_ccn_exit(void) { + cpuhp_remove_state_nocalls(CPUHP_AP_PERF_ARM_CCN_ONLINE); platform_driver_unregister(&arm_ccn_driver); } -- cgit v1.2.3-58-ga151