arm/perf: Fix hotplug state machine conversion
Mark Rutland pointed out that this commit is incomplete:
7d88eb695a
("arm/perf: Convert to hotplug state machine")
The problem is that:
> We may have multiple PMUs (e.g. two in big.LITTLE systems), and
> __oprofile_cpu_pmu only contains one of these. So this conversion is not
> correct.
>
> We were relying on the notifier list implicitly containing a list of
> those PMUs. It seems like we need an explicit list here.
>
> We keep __oprofile_cpu_pmu around for legacy 32-bit users of OProfile
> (on non-hetereogeneous systems), and that's all that the variable should
> be used for.
Introduce arm_pmu_list to correctly handle multiple PMUs in the system.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-tip-commits@vger.kernel.org
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160719111733.GA22911@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
parent
c76c15e6f1
commit
37b502f121
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@ -685,6 +685,9 @@ static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler)
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return 0;
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}
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static DEFINE_MUTEX(arm_pmu_mutex);
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static LIST_HEAD(arm_pmu_list);
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/*
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* PMU hardware loses all context when a CPU goes offline.
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* When a CPU is hotplugged back in, since some hardware registers are
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@ -693,12 +696,17 @@ static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler)
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*/
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static int arm_perf_starting_cpu(unsigned int cpu)
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{
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if (!__oprofile_cpu_pmu)
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return 0;
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if (!cpumask_test_cpu(cpu, &__oprofile_cpu_pmu->supported_cpus))
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return 0;
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if (__oprofile_cpu_pmu->reset)
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__oprofile_cpu_pmu->reset(__oprofile_cpu_pmu);
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struct arm_pmu *pmu;
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mutex_lock(&arm_pmu_mutex);
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list_for_each_entry(pmu, &arm_pmu_list, entry) {
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if (!cpumask_test_cpu(cpu, &pmu->supported_cpus))
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continue;
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if (pmu->reset)
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pmu->reset(pmu);
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}
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mutex_unlock(&arm_pmu_mutex);
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return 0;
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}
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@ -810,11 +818,9 @@ static int cpu_pmu_init(struct arm_pmu *cpu_pmu)
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if (!cpu_hw_events)
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return -ENOMEM;
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err = cpuhp_setup_state_nocalls(CPUHP_AP_PERF_ARM_STARTING,
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"AP_PERF_ARM_STARTING",
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arm_perf_starting_cpu, NULL);
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if (err)
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goto out_hw_events;
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mutex_lock(&arm_pmu_mutex);
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list_add_tail(&cpu_pmu->entry, &arm_pmu_list);
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mutex_unlock(&arm_pmu_mutex);
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err = cpu_pm_pmu_register(cpu_pmu);
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if (err)
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@ -850,8 +856,9 @@ static int cpu_pmu_init(struct arm_pmu *cpu_pmu)
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return 0;
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out_unregister:
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cpuhp_remove_state_nocalls(CPUHP_AP_PERF_ARM_STARTING);
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out_hw_events:
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mutex_lock(&arm_pmu_mutex);
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list_del(&cpu_pmu->entry);
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mutex_unlock(&arm_pmu_mutex);
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free_percpu(cpu_hw_events);
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return err;
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}
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@ -859,7 +866,9 @@ out_hw_events:
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static void cpu_pmu_destroy(struct arm_pmu *cpu_pmu)
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{
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cpu_pm_pmu_unregister(cpu_pmu);
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cpuhp_remove_state_nocalls(CPUHP_AP_PERF_ARM_STARTING);
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mutex_lock(&arm_pmu_mutex);
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list_del(&cpu_pmu->entry);
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mutex_unlock(&arm_pmu_mutex);
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free_percpu(cpu_pmu->hw_events);
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}
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@ -1019,8 +1028,6 @@ int arm_pmu_device_probe(struct platform_device *pdev,
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if (ret)
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goto out_destroy;
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WARN(__oprofile_cpu_pmu, "%s(): missing PMU strucure for CPU-hotplug\n",
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__func__);
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if (!__oprofile_cpu_pmu)
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__oprofile_cpu_pmu = pmu;
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@ -1038,3 +1045,17 @@ out_free:
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kfree(pmu);
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return ret;
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}
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static int arm_pmu_hp_init(void)
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{
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int ret;
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ret = cpuhp_setup_state_nocalls(CPUHP_AP_PERF_ARM_STARTING,
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"AP_PERF_ARM_STARTING",
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arm_perf_starting_cpu, NULL);
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if (ret)
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pr_err("CPU hotplug notifier for ARM PMU could not be registered: %d\n",
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ret);
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return ret;
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}
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subsys_initcall(arm_pmu_hp_init);
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@ -109,6 +109,7 @@ struct arm_pmu {
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DECLARE_BITMAP(pmceid_bitmap, ARMV8_PMUV3_MAX_COMMON_EVENTS);
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struct platform_device *plat_device;
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struct pmu_hw_events __percpu *hw_events;
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struct list_head entry;
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struct notifier_block cpu_pm_nb;
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};
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