[patch 34/66] arm: perf: Convert to hotplug state machine

From: Anna-Maria Gleixner
Date: Mon Jul 11 2016 - 08:40:51 EST


From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

Straight forward conversion w/o bells and whistles.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Anna-Maria Gleixner <anna-maria@xxxxxxxxxxxxx>

---
drivers/perf/arm_pmu.c | 36 +++++++++++++++---------------------
include/linux/cpuhotplug.h | 1 +
include/linux/perf/arm_pmu.h | 1 -
3 files changed, 16 insertions(+), 22 deletions(-)

--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -691,24 +691,15 @@ static int cpu_pmu_request_irq(struct ar
* UNKNOWN at reset, the PMU must be explicitly reset to avoid reading
* junk values out of them.
*/
-static int cpu_pmu_notify(struct notifier_block *b, unsigned long action,
- void *hcpu)
+static int arm_perf_starting_cpu(unsigned int cpu)
{
- int cpu = (unsigned long)hcpu;
- struct arm_pmu *pmu = container_of(b, struct arm_pmu, hotplug_nb);
-
- if ((action & ~CPU_TASKS_FROZEN) != CPU_STARTING)
- return NOTIFY_DONE;
-
- if (!cpumask_test_cpu(cpu, &pmu->supported_cpus))
- return NOTIFY_DONE;
-
- if (pmu->reset)
- pmu->reset(pmu);
- else
- return NOTIFY_DONE;
-
- return NOTIFY_OK;
+ if (!__oprofile_cpu_pmu)
+ return 0;
+ if (!cpumask_test_cpu(cpu, &__oprofile_cpu_pmu->supported_cpus))
+ return 0;
+ if (__oprofile_cpu_pmu->reset)
+ __oprofile_cpu_pmu->reset(__oprofile_cpu_pmu);
+ return 0;
}

#ifdef CONFIG_CPU_PM
@@ -819,8 +810,9 @@ static int cpu_pmu_init(struct arm_pmu *
if (!cpu_hw_events)
return -ENOMEM;

- cpu_pmu->hotplug_nb.notifier_call = cpu_pmu_notify;
- err = register_cpu_notifier(&cpu_pmu->hotplug_nb);
+ err = cpuhp_setup_state_nocalls(CPUHP_AP_PERF_ARM_STARTING,
+ "AP_PERF_ARM_STARTING",
+ arm_perf_starting_cpu, NULL);
if (err)
goto out_hw_events;

@@ -858,7 +850,7 @@ static int cpu_pmu_init(struct arm_pmu *
return 0;

out_unregister:
- unregister_cpu_notifier(&cpu_pmu->hotplug_nb);
+ cpuhp_remove_state_nocalls(CPUHP_AP_PERF_ARM_STARTING);
out_hw_events:
free_percpu(cpu_hw_events);
return err;
@@ -867,7 +859,7 @@ static int cpu_pmu_init(struct arm_pmu *
static void cpu_pmu_destroy(struct arm_pmu *cpu_pmu)
{
cpu_pm_pmu_unregister(cpu_pmu);
- unregister_cpu_notifier(&cpu_pmu->hotplug_nb);
+ cpuhp_remove_state_nocalls(CPUHP_AP_PERF_ARM_STARTING);
free_percpu(cpu_pmu->hw_events);
}

@@ -1027,6 +1019,8 @@ int arm_pmu_device_probe(struct platform
if (ret)
goto out_destroy;

+ WARN(__oprofile_cpu_pmu, "%s(): missing PMU strucure for CPU-hotplug\n",
+ __func__);
if (!__oprofile_cpu_pmu)
__oprofile_cpu_pmu = pmu;

--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -36,6 +36,7 @@ enum cpuhp_state {
CPUHP_AP_PERF_X86_CSTATE_STARTING,
CPUHP_AP_PERF_XTENSA_STARTING,
CPUHP_AP_ARM_VFP_STARTING,
+ CPUHP_AP_PERF_ARM_STARTING,
CPUHP_AP_NOTIFY_STARTING,
CPUHP_AP_ONLINE,
CPUHP_TEARDOWN_CPU,
--- a/include/linux/perf/arm_pmu.h
+++ b/include/linux/perf/arm_pmu.h
@@ -109,7 +109,6 @@ 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 notifier_block hotplug_nb;
struct notifier_block cpu_pm_nb;
};