perf: Split the per-cpu accounting part of the event accounting code

This way we can use the per-cpu handling seperately.
This is going to be used by to fix the event migration
code accounting.

Original-patch-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1374539466-4799-5-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

kernel/events/core.c

@@ -3128,6 +3128,40 @@ static void free_event_rcu(struct rcu_head *head)
 static void ring_buffer_put(struct ring_buffer *rb);
 static void ring_buffer_detach(struct perf_event *event, struct ring_buffer *rb);
 
+static void unaccount_event_cpu(struct perf_event *event, int cpu)
+{
+	if (event->parent)
+		return;
+
+	if (has_branch_stack(event)) {
+		if (!(event->attach_state & PERF_ATTACH_TASK))
+			atomic_dec(&per_cpu(perf_branch_stack_events, cpu));
+	}
+	if (is_cgroup_event(event))
+		atomic_dec(&per_cpu(perf_cgroup_events, cpu));
+}
+
+static void unaccount_event(struct perf_event *event)
+{
+	if (event->parent)
+		return;
+
+	if (event->attach_state & PERF_ATTACH_TASK)
+		static_key_slow_dec_deferred(&perf_sched_events);
+	if (event->attr.mmap || event->attr.mmap_data)
+		atomic_dec(&nr_mmap_events);
+	if (event->attr.comm)
+		atomic_dec(&nr_comm_events);
+	if (event->attr.task)
+		atomic_dec(&nr_task_events);
+	if (is_cgroup_event(event))
+		static_key_slow_dec_deferred(&perf_sched_events);
+	if (has_branch_stack(event))
+		static_key_slow_dec_deferred(&perf_sched_events);
+
+	unaccount_event_cpu(event, event->cpu);
+}
+
 static void __free_event(struct perf_event *event)
 {
 	if (!event->parent) {
@@ -3147,29 +3181,7 @@ static void free_event(struct perf_event *event)
 {
 	irq_work_sync(&event->pending);
 
-	if (!event->parent) {
-		if (event->attach_state & PERF_ATTACH_TASK)
-			static_key_slow_dec_deferred(&perf_sched_events);
-		if (event->attr.mmap || event->attr.mmap_data)
-			atomic_dec(&nr_mmap_events);
-		if (event->attr.comm)
-			atomic_dec(&nr_comm_events);
-		if (event->attr.task)
-			atomic_dec(&nr_task_events);
-		if (is_cgroup_event(event)) {
-			atomic_dec(&per_cpu(perf_cgroup_events, event->cpu));
-			static_key_slow_dec_deferred(&perf_sched_events);
-		}
-
-		if (has_branch_stack(event)) {
-			static_key_slow_dec_deferred(&perf_sched_events);
-			/* is system-wide event */
-			if (!(event->attach_state & PERF_ATTACH_TASK)) {
-				atomic_dec(&per_cpu(perf_branch_stack_events,
-						    event->cpu));
-			}
-		}
-	}
+	unaccount_event(event);
 
 	if (event->rb) {
 		struct ring_buffer *rb;
@@ -6451,8 +6463,24 @@ unlock:
 	return pmu;
 }
 
+static void account_event_cpu(struct perf_event *event, int cpu)
+{
+	if (event->parent)
+		return;
+
+	if (has_branch_stack(event)) {
+		if (!(event->attach_state & PERF_ATTACH_TASK))
+			atomic_inc(&per_cpu(perf_branch_stack_events, cpu));
+	}
+	if (is_cgroup_event(event))
+		atomic_inc(&per_cpu(perf_cgroup_events, cpu));
+}
+
 static void account_event(struct perf_event *event)
 {
+	if (event->parent)
+		return;
+
 	if (event->attach_state & PERF_ATTACH_TASK)
 		static_key_slow_inc(&perf_sched_events.key);
 	if (event->attr.mmap || event->attr.mmap_data)
@@ -6461,17 +6489,12 @@ static void account_event(struct perf_event *event)
 		atomic_inc(&nr_comm_events);
 	if (event->attr.task)
 		atomic_inc(&nr_task_events);
-	if (has_branch_stack(event)) {
+	if (has_branch_stack(event))
 		static_key_slow_inc(&perf_sched_events.key);
-		if (!(event->attach_state & PERF_ATTACH_TASK))
-			atomic_inc(&per_cpu(perf_branch_stack_events,
-					    event->cpu));
-	}
-
-	if (is_cgroup_event(event)) {
-		atomic_inc(&per_cpu(perf_cgroup_events, event->cpu));
+	if (is_cgroup_event(event))
 		static_key_slow_inc(&perf_sched_events.key);
-	}
+
+	account_event_cpu(event, event->cpu);
 }
 
 /*