1 files changed, 63 insertions, 13 deletions

diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index e7eeba1794fd..634f86a4b2f9 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -412,8 +412,8 @@ event_filter_match(struct perf_event *event)
         return event->cpu == -1 || event->cpu == smp_processor_id();
 }
 
-static void
-event_sched_out(struct perf_event *event,
+static int
+__event_sched_out(struct perf_event *event,
                   struct perf_cpu_context *cpuctx,
                   struct perf_event_context *ctx)
 {
@@ -432,14 +432,13 @@ event_sched_out(struct perf_event *event,
         }
 
         if (event->state != PERF_EVENT_STATE_ACTIVE)
-                return;
+                return 0;
 
         event->state = PERF_EVENT_STATE_INACTIVE;
         if (event->pending_disable) {
                 event->pending_disable = 0;
                 event->state = PERF_EVENT_STATE_OFF;
         }
-        event->tstamp_stopped = ctx->time;
         event->pmu->del(event, 0);
         event->oncpu = -1;
 
@@ -448,6 +447,19 @@ event_sched_out(struct perf_event *event,
         ctx->nr_active--;
         if (event->attr.exclusive || !cpuctx->active_oncpu)
                 cpuctx->exclusive = 0;
+        return 1;
+}
+
+static void
+event_sched_out(struct perf_event *event,
+                  struct perf_cpu_context *cpuctx,
+                  struct perf_event_context *ctx)
+{
+        int ret;
+
+        ret = __event_sched_out(event, cpuctx, ctx);
+        if (ret)
+                event->tstamp_stopped = ctx->time;
 }
 
 static void
@@ -647,7 +659,7 @@ retry:
 }
 
 static int
-event_sched_in(struct perf_event *event,
+__event_sched_in(struct perf_event *event,
                  struct perf_cpu_context *cpuctx,
                  struct perf_event_context *ctx)
 {
@@ -667,8 +679,6 @@ event_sched_in(struct perf_event *event,
                 return -EAGAIN;
         }
 
-        event->tstamp_running += ctx->time - event->tstamp_stopped;
-
         if (!is_software_event(event))
                 cpuctx->active_oncpu++;
         ctx->nr_active++;
@@ -679,6 +689,35 @@ event_sched_in(struct perf_event *event,
         return 0;
 }
 
+static inline int
+event_sched_in(struct perf_event *event,
+                 struct perf_cpu_context *cpuctx,
+                 struct perf_event_context *ctx)
+{
+        int ret = __event_sched_in(event, cpuctx, ctx);
+        if (ret)
+                return ret;
+        event->tstamp_running += ctx->time - event->tstamp_stopped;
+        return 0;
+}
+
+static void
+group_commit_event_sched_in(struct perf_event *group_event,
+               struct perf_cpu_context *cpuctx,
+               struct perf_event_context *ctx)
+{
+        struct perf_event *event;
+        u64 now = ctx->time;
+
+        group_event->tstamp_running += now - group_event->tstamp_stopped;
+        /*
+         * Schedule in siblings as one group (if any):
+         */
+        list_for_each_entry(event, &group_event->sibling_list, group_entry) {
+                event->tstamp_running += now - event->tstamp_stopped;
+        }
+}
+
 static int
 group_sched_in(struct perf_event *group_event,
                struct perf_cpu_context *cpuctx,
@@ -692,7 +731,13 @@ group_sched_in(struct perf_event *group_event,
 
         pmu->start_txn(pmu);
 
-        if (event_sched_in(group_event, cpuctx, ctx)) {
+        /*
+         * use __event_sched_in() to delay updating tstamp_running
+         * until the transaction is committed. In case of failure
+         * we will keep an unmodified tstamp_running which is a
+         * requirement to get correct timing information
+         */
+        if (__event_sched_in(group_event, cpuctx, ctx)) {
                 pmu->cancel_txn(pmu);
                 return -EAGAIN;
         }
@@ -701,26 +746,31 @@ group_sched_in(struct perf_event *group_event,
          * Schedule in siblings as one group (if any):
          */
         list_for_each_entry(event, &group_event->sibling_list, group_entry) {
-                if (event_sched_in(event, cpuctx, ctx)) {
+                if (__event_sched_in(event, cpuctx, ctx)) {
                         partial_group = event;
                         goto group_error;
                 }
         }
 
-        if (!pmu->commit_txn(pmu))
+        if (!pmu->commit_txn(pmu)) {
+                /* commit tstamp_running */
+                group_commit_event_sched_in(group_event, cpuctx, ctx);
                 return 0;
-
+        }
 group_error:
         /*
          * Groups can be scheduled in as one unit only, so undo any
          * partial group before returning:
+         *
+         * use __event_sched_out() to avoid updating tstamp_stopped
+         * because the event never actually ran
          */
         list_for_each_entry(event, &group_event->sibling_list, group_entry) {
                 if (event == partial_group)
                         break;
-                event_sched_out(event, cpuctx, ctx);
+                __event_sched_out(event, cpuctx, ctx);
         }
-        event_sched_out(group_event, cpuctx, ctx);
+        __event_sched_out(group_event, cpuctx, ctx);
 
         pmu->cancel_txn(pmu);