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>

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index dfa725723f287e3313219b3ecb45c7a42c5ef627..5c58e93c130c9f36b0738e2b3927f1fc71ae204a 100644 (file)
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -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;

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 928a818d912ed7796ac78619e087737e39d9b631..d92c7ad7715db6aa24018215a012e86186ad8694 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -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: