Commit 1fd7e416 authored Jan 18, 2017 by David Carrillo-Cisneros Committed by Ingo Molnar Jan 30, 2017

perf/core: Remove perf_cpu_context::unique_pmu



cpuctx->unique_pmu was originally introduced as a way to identify cpuctxs
with shared pmus in order to avoid visiting the same cpuctx more than once
in a for_each_pmu loop.

cpuctx->unique_pmu == cpuctx->pmu in non-software task contexts since they
have only one pmu per cpuctx. Since perf_pmu_sched_task() is only called in
hw contexts, this patch replaces cpuctx->unique_pmu by cpuctx->pmu in it.

The change above, together with the previous patch in this series, removed
the remaining uses of cpuctx->unique_pmu, so we remove it altogether.

Signed-off-by: David Carrillo-Cisneros <davidcc@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Cc: Vince Weaver <vince@deater.net>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/20170118192454.58008-3-davidcc@google.com


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent 058fe1c0

include/linux/perf_event.h

+0 −1

Original line number	Diff line number	Diff line
		@@ -785,7 +785,6 @@ struct perf_cpu_context {
		ktime_t hrtimer_interval;
		unsigned int hrtimer_active;

		struct pmu *unique_pmu;
		#ifdef CONFIG_CGROUP_PERF
		struct perf_cgroup *cgrp;
		struct list_head cgrp_cpuctx_entry;

kernel/events/core.c

+1 −30

Original line number	Diff line number	Diff line
		@@ -2932,7 +2932,7 @@ static void perf_pmu_sched_task(struct task_struct *prev,
		return;

		list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
		pmu = cpuctx->unique_pmu; /* software PMUs will not have sched_task */
		pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */

		if (WARN_ON_ONCE(!pmu->sched_task))
		continue;
		@@ -8636,37 +8636,10 @@ static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
		return NULL;
		}

		static void update_pmu_context(struct pmu pmu, struct pmu old_pmu)
		{
		int cpu;

		for_each_possible_cpu(cpu) {
		struct perf_cpu_context *cpuctx;

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

		if (cpuctx->unique_pmu == old_pmu)
		cpuctx->unique_pmu = pmu;
		}
		}

		static void free_pmu_context(struct pmu *pmu)
		{
		struct pmu *i;

		mutex_lock(&pmus_lock);
		/*
		* Like a real lame refcount.
		*/
		list_for_each_entry(i, &pmus, entry) {
		if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
		update_pmu_context(i, pmu);
		goto out;
		}
		}

		free_percpu(pmu->pmu_cpu_context);
		out:
		mutex_unlock(&pmus_lock);
		}

		@@ -8870,8 +8843,6 @@ skip_type:
		cpuctx->ctx.pmu = pmu;

		__perf_mux_hrtimer_init(cpuctx, cpu);

		cpuctx->unique_pmu = pmu;
		}

		got_cpu_context:

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