perf: Factor out event accounting code to account_event()/__free_event()

Gather all the event accounting code to a single place,
once all the prerequisites are completed. This simplifies
the refcounting.

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/1374539466-4799-4-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 47 insertions, 32 deletions

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 3b998626b7a0..158fd5789e58 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3128,6 +3128,21 @@ 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 __free_event(struct perf_event *event)
+{
+        if (!event->parent) {
+                if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
+                        put_callchain_buffers();
+        }
+
+        if (event->destroy)
+                event->destroy(event);
+
+        if (event->ctx)
+                put_ctx(event->ctx);
+
+        call_rcu(&event->rcu_head, free_event_rcu);
+}
 static void free_event(struct perf_event *event)
 {
         irq_work_sync(&event->pending);
@@ -3141,8 +3156,6 @@ static void free_event(struct perf_event *event)
                         atomic_dec(&nr_comm_events);
                 if (event->attr.task)
                         atomic_dec(&nr_task_events);
-                if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
-                        put_callchain_buffers();
                 if (is_cgroup_event(event)) {
                         atomic_dec(&per_cpu(perf_cgroup_events, event->cpu));
                         static_key_slow_dec_deferred(&perf_sched_events);
@@ -3180,13 +3193,8 @@ static void free_event(struct perf_event *event)
         if (is_cgroup_event(event))
                 perf_detach_cgroup(event);
 
-        if (event->destroy)
-                event->destroy(event);
-
-        if (event->ctx)
-                put_ctx(event->ctx);
 
-        call_rcu(&event->rcu_head, free_event_rcu);
+        __free_event(event);
 }
 
 int perf_event_release_kernel(struct perf_event *event)
@@ -6443,6 +6451,29 @@ unlock:
         return pmu;
 }
 
+static void account_event(struct perf_event *event)
+{
+        if (event->attach_state & PERF_ATTACH_TASK)
+                static_key_slow_inc(&perf_sched_events.key);
+        if (event->attr.mmap || event->attr.mmap_data)
+                atomic_inc(&nr_mmap_events);
+        if (event->attr.comm)
+                atomic_inc(&nr_comm_events);
+        if (event->attr.task)
+                atomic_inc(&nr_task_events);
+        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));
+                static_key_slow_inc(&perf_sched_events.key);
+        }
+}
+
 /*
  * Allocate and initialize a event structure
  */
@@ -6556,21 +6587,6 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
                         if (err)
                                 goto err_pmu;
                 }
-
-                if (event->attach_state & PERF_ATTACH_TASK)
-                        static_key_slow_inc(&perf_sched_events.key);
-                if (event->attr.mmap || event->attr.mmap_data)
-                        atomic_inc(&nr_mmap_events);
-                if (event->attr.comm)
-                        atomic_inc(&nr_comm_events);
-                if (event->attr.task)
-                        atomic_inc(&nr_task_events);
-                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));
-                }
         }
 
         return event;
@@ -6865,17 +6881,14 @@ SYSCALL_DEFINE5(perf_event_open,
 
         if (flags & PERF_FLAG_PID_CGROUP) {
                 err = perf_cgroup_connect(pid, event, &attr, group_leader);
-                if (err)
-                        goto err_alloc;
-                /*
-                 * one more event:
-                 * - that has cgroup constraint on event->cpu
-                 * - that may need work on context switch
-                 */
-                atomic_inc(&per_cpu(perf_cgroup_events, event->cpu));
-                static_key_slow_inc(&perf_sched_events.key);
+                if (err) {
+                        __free_event(event);
+                        goto err_task;
+                }
         }
 
+        account_event(event);
+
         /*
          * Special case software events and allow them to be part of
          * any hardware group.
@@ -7071,6 +7084,8 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
                 goto err;
         }
 
+        account_event(event);
+
         ctx = find_get_context(event->pmu, task, cpu);
         if (IS_ERR(ctx)) {
                 err = PTR_ERR(ctx);