2 files changed, 16 insertions, 19 deletions

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index cdbc2aa64a0b..c6f812e4d058 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -565,6 +565,10 @@ typedef void (*perf_overflow_handler_t)(struct perf_event *, int,
                                         struct perf_sample_data *,
                                         struct pt_regs *regs);
 
+enum perf_group_flag {
+        PERF_GROUP_SOFTWARE = 0x1,
+};
+
 /**
  * struct perf_event - performance event kernel representation:
  */
@@ -574,6 +578,7 @@ struct perf_event {
         struct list_head                event_entry;
         struct list_head                sibling_list;
         int                             nr_siblings;
+        int                             group_flags;
         struct perf_event               *group_leader;
         struct perf_event               *output;
         const struct pmu                *pmu;
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index bbebe2832639..eae6ff693604 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -315,9 +315,16 @@ list_add_event(struct perf_event *event, struct perf_event_context *ctx)
         if (group_leader == event) {
                 struct list_head *list;
 
+                if (is_software_event(event))
+                        event->group_flags |= PERF_GROUP_SOFTWARE;
+
                 list = ctx_group_list(event, ctx);
                 list_add_tail(&event->group_entry, list);
         } else {
+                if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
+                    !is_software_event(event))
+                        group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
+
                 list_add_tail(&event->group_entry, &group_leader->sibling_list);
                 group_leader->nr_siblings++;
         }
@@ -372,6 +379,9 @@ list_del_event(struct perf_event *event, struct perf_event_context *ctx)
                 list = ctx_group_list(event, ctx);
                 list_move_tail(&sibling->group_entry, list);
                 sibling->group_leader = sibling;
+
+                /* Inherit group flags from the previous leader */
+                sibling->group_flags = event->group_flags;
         }
 }
 
@@ -700,24 +710,6 @@ group_error:
 }
 
 /*
- * Return 1 for a group consisting entirely of software events,
- * 0 if the group contains any hardware events.
- */
-static int is_software_only_group(struct perf_event *leader)
-{
-        struct perf_event *event;
-
-        if (!is_software_event(leader))
-                return 0;
-
-        list_for_each_entry(event, &leader->sibling_list, group_entry)
-                if (!is_software_event(event))
-                        return 0;
-
-        return 1;
-}
-
-/*
  * Work out whether we can put this event group on the CPU now.
  */
 static int group_can_go_on(struct perf_event *event,
@@ -727,7 +719,7 @@ static int group_can_go_on(struct perf_event *event,
         /*
          * Groups consisting entirely of software events can always go on.
          */
-        if (is_software_only_group(event))
+        if (event->group_flags & PERF_GROUP_SOFTWARE)
                 return 1;
         /*
          * If an exclusive group is already on, no other hardware