arm/perf: Use multi instance instead of custom list

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160817171420.sdwk2qivxunzryz4@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index c494613c1909e16b88f06c0270bee1425239e5f3..b2f742f84111e7a8541f0cf5cd133ae911a042fe 100644 (file)
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -688,28 +688,20 @@ static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler)
        return 0;
 }
 
-static DEFINE_SPINLOCK(arm_pmu_lock);
-static LIST_HEAD(arm_pmu_list);
-
 /*
  * PMU hardware loses all context when a CPU goes offline.
  * When a CPU is hotplugged back in, since some hardware registers are
  * UNKNOWN at reset, the PMU must be explicitly reset to avoid reading
  * junk values out of them.
  */
-static int arm_perf_starting_cpu(unsigned int cpu)
+static int arm_perf_starting_cpu(unsigned int cpu, struct hlist_node *node)
 {
-       struct arm_pmu *pmu;
-
-       spin_lock(&arm_pmu_lock);
-       list_for_each_entry(pmu, &arm_pmu_list, entry) {
+       struct arm_pmu *pmu = hlist_entry_safe(node, struct arm_pmu, node);
 
-               if (!cpumask_test_cpu(cpu, &pmu->supported_cpus))
-                       continue;
-               if (pmu->reset)
-                       pmu->reset(pmu);
-       }
-       spin_unlock(&arm_pmu_lock);
+       if (!cpumask_test_cpu(cpu, &pmu->supported_cpus))
+               return 0;
+       if (pmu->reset)
+               pmu->reset(pmu);
        return 0;
 }
 
@@ -821,9 +813,10 @@ static int cpu_pmu_init(struct arm_pmu *cpu_pmu)
        if (!cpu_hw_events)
                return -ENOMEM;
 
-       spin_lock(&arm_pmu_lock);
-       list_add_tail(&cpu_pmu->entry, &arm_pmu_list);
-       spin_unlock(&arm_pmu_lock);
+       err = cpuhp_state_add_instance_nocalls(CPUHP_AP_PERF_ARM_STARTING,
+                                              &cpu_pmu->node);
+       if (err)
+               goto out_free;
 
        err = cpu_pm_pmu_register(cpu_pmu);
        if (err)
@@ -859,9 +852,9 @@ static int cpu_pmu_init(struct arm_pmu *cpu_pmu)
        return 0;
 
 out_unregister:
-       spin_lock(&arm_pmu_lock);
-       list_del(&cpu_pmu->entry);
-       spin_unlock(&arm_pmu_lock);
+       cpuhp_state_remove_instance_nocalls(CPUHP_AP_PERF_ARM_STARTING,
+                                           &cpu_pmu->node);
+out_free:
        free_percpu(cpu_hw_events);
        return err;
 }
@@ -869,9 +862,8 @@ out_unregister:
 static void cpu_pmu_destroy(struct arm_pmu *cpu_pmu)
 {
        cpu_pm_pmu_unregister(cpu_pmu);
-       spin_lock(&arm_pmu_lock);
-       list_del(&cpu_pmu->entry);
-       spin_unlock(&arm_pmu_lock);
+       cpuhp_state_remove_instance_nocalls(CPUHP_AP_PERF_ARM_STARTING,
+                                           &cpu_pmu->node);
        free_percpu(cpu_pmu->hw_events);
 }
 
@@ -1068,9 +1060,9 @@ static int arm_pmu_hp_init(void)
 {
        int ret;
 
-       ret = cpuhp_setup_state_nocalls(CPUHP_AP_PERF_ARM_STARTING,
-                                       "AP_PERF_ARM_STARTING",
-                                       arm_perf_starting_cpu, NULL);
+       ret = cpuhp_setup_state_multi(CPUHP_AP_PERF_ARM_STARTING,
+                                     "AP_PERF_ARM_STARTING",
+                                     arm_perf_starting_cpu, NULL);
        if (ret)
                pr_err("CPU hotplug notifier for ARM PMU could not be registered: %d\n",
                       ret);

diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h
index e18843809eec0f598018919e002dfb8dee58360d..4ad1b408c0bba6766587338edb22039be90bb85b 100644 (file)
--- a/include/linux/perf/arm_pmu.h
+++ b/include/linux/perf/arm_pmu.h
@@ -109,7 +109,7 @@ struct arm_pmu {
        DECLARE_BITMAP(pmceid_bitmap, ARMV8_PMUV3_MAX_COMMON_EVENTS);
        struct platform_device  *plat_device;
        struct pmu_hw_events    __percpu *hw_events;
-       struct list_head        entry;
+       struct hlist_node       node;
        struct notifier_block   cpu_pm_nb;
 };