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Commit 3f1f3320 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
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perf: Clarify perf_cpu_context::active_pmu usage by renaming it to ::unique_pmu 



Stephane thought the perf_cpu_context::active_pmu name confusing and
suggested using 'unique_pmu' instead.

This pointer is a pointer to a 'random' pmu sharing the cpuctx
instance, therefore limiting a for_each_pmu loop to those where
cpuctx->unique_pmu matches the pmu we get a loop over unique cpuctx
instances.

Suggested-by: default avatarStephane Eranian <eranian@google.com>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-kxyjqpfj2fn9gt7kwu5ag9ks@git.kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 2e132b12

include/linux/perf_event.h

+1 −1
Original line number Diff line number Diff line
@@ -1110,7 +1110,7 @@ struct perf_cpu_context { 
	int				exclusive;

	struct list_head		rotation_list;

	int				jiffies_interval;

	struct pmu			*active_pmu;

	struct pmu			*unique_pmu;

	struct perf_cgroup		*cgrp;

};

kernel/events/core.c

+6 −6
Original line number Diff line number Diff line
@@ -4419,7 +4419,7 @@ static void perf_event_task_event(struct perf_task_event *task_event) 
	rcu_read_lock();

	list_for_each_entry_rcu(pmu, &pmus, entry) {

		cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);

		if (cpuctx->active_pmu != pmu)

		if (cpuctx->unique_pmu != pmu)

			goto next;

		perf_event_task_ctx(&cpuctx->ctx, task_event);
@@ -4565,7 +4565,7 @@ static void perf_event_comm_event(struct perf_comm_event *comm_event) 
	rcu_read_lock();

	list_for_each_entry_rcu(pmu, &pmus, entry) {

		cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);

		if (cpuctx->active_pmu != pmu)

		if (cpuctx->unique_pmu != pmu)

			goto next;

		perf_event_comm_ctx(&cpuctx->ctx, comm_event);
@@ -4761,7 +4761,7 @@ got_name: 
	rcu_read_lock();

	list_for_each_entry_rcu(pmu, &pmus, entry) {

		cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);

		if (cpuctx->active_pmu != pmu)

		if (cpuctx->unique_pmu != pmu)

			goto next;

		perf_event_mmap_ctx(&cpuctx->ctx, mmap_event,

					vma->vm_flags & VM_EXEC);
@@ -5862,8 +5862,8 @@ static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu) 


		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);



		if (cpuctx->active_pmu == old_pmu)

			cpuctx->active_pmu = pmu;

		if (cpuctx->unique_pmu == old_pmu)

			cpuctx->unique_pmu = pmu;

	}

}
@@ -5998,7 +5998,7 @@ skip_type: 
		cpuctx->ctx.pmu = pmu;

		cpuctx->jiffies_interval = 1;

		INIT_LIST_HEAD(&cpuctx->rotation_list);

		cpuctx->active_pmu = pmu;

		cpuctx->unique_pmu = pmu;

	}



got_cpu_context: