2 files changed, 32 insertions, 16 deletions

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 23cd0057a681..4924c96d7e2d 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -547,6 +547,8 @@ struct hw_perf_event {
 
 struct perf_event;
 
+#define PERF_EVENT_TXN_STARTED 1
+
 /**
  * struct pmu - generic performance monitoring unit
  */
@@ -557,6 +559,16 @@ struct pmu {
         void (*stop)                    (struct perf_event *event);
         void (*read)                    (struct perf_event *event);
         void (*unthrottle)              (struct perf_event *event);
+
+        /*
+         * group events scheduling is treated as a transaction,
+         * add group events as a whole and perform one schedulability test.
+         * If test fails, roll back the whole group
+         */
+
+        void (*start_txn)       (const struct pmu *pmu);
+        void (*cancel_txn)      (const struct pmu *pmu);
+        int  (*commit_txn)      (const struct pmu *pmu);
 };
 
 /**
@@ -823,9 +835,6 @@ extern void perf_disable(void);
 extern void perf_enable(void);
 extern int perf_event_task_disable(void);
 extern int perf_event_task_enable(void);
-extern int hw_perf_group_sched_in(struct perf_event *group_leader,
-               struct perf_cpu_context *cpuctx,
-               struct perf_event_context *ctx);
 extern void perf_event_update_userpage(struct perf_event *event);
 extern int perf_event_release_kernel(struct perf_event *event);
 extern struct perf_event *
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 34659d4085c7..bb06382f98e7 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -83,14 +83,6 @@ extern __weak const struct pmu *hw_perf_event_init(struct perf_event *event)
 void __weak hw_perf_disable(void)               { barrier(); }
 void __weak hw_perf_enable(void)                { barrier(); }
 
-int __weak
-hw_perf_group_sched_in(struct perf_event *group_leader,
-               struct perf_cpu_context *cpuctx,
-               struct perf_event_context *ctx)
-{
-        return 0;
-}
-
 void __weak perf_event_print_debug(void)        { }
 
 static DEFINE_PER_CPU(int, perf_disable_count);
@@ -644,15 +636,20 @@ group_sched_in(struct perf_event *group_event,
                struct perf_cpu_context *cpuctx,
                struct perf_event_context *ctx)
 {
-        struct perf_event *event, *partial_group;
+        struct perf_event *event, *partial_group = NULL;
+        const struct pmu *pmu = group_event->pmu;
+        bool txn = false;
         int ret;
 
         if (group_event->state == PERF_EVENT_STATE_OFF)
                 return 0;
 
-        ret = hw_perf_group_sched_in(group_event, cpuctx, ctx);
-        if (ret)
-                return ret < 0 ? ret : 0;
+        /* Check if group transaction availabe */
+        if (pmu->start_txn)
+                txn = true;
+
+        if (txn)
+                pmu->start_txn(pmu);
 
         if (event_sched_in(group_event, cpuctx, ctx))
                 return -EAGAIN;
@@ -667,9 +664,19 @@ group_sched_in(struct perf_event *group_event,
                 }
         }
 
-        return 0;
+        if (txn) {
+                ret = pmu->commit_txn(pmu);
+                if (!ret) {
+                        pmu->cancel_txn(pmu);
+
+                        return 0;
+                }
+        }
 
 group_error:
+        if (txn)
+                pmu->cancel_txn(pmu);
+
         /*
          * Groups can be scheduled in as one unit only, so undo any
          * partial group before returning: