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: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-kxyjqpfj2fn9gt7kwu5ag9ks@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

2 files changed, 7 insertions, 7 deletions

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 599afc4bb67e..b4166cdfa7a2 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -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;
 };
 
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 7b9df353ba1b..81939e8999a5 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -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: