perfcounters: tweak group scheduling
Impact: schedule in groups atomically
If there are multiple groups in a task, make sure they are scheduled
in and out atomically.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index aab6c12..f8a4d9a 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -367,21 +367,26 @@
ctx->nr_active++;
}
-static void
+static int
group_sched_in(struct perf_counter *group_counter,
struct perf_cpu_context *cpuctx,
struct perf_counter_context *ctx,
int cpu)
{
struct perf_counter *counter;
+ int was_group = 0;
counter_sched_in(group_counter, cpuctx, ctx, cpu);
/*
* Schedule in siblings as one group (if any):
*/
- list_for_each_entry(counter, &group_counter->sibling_list, list_entry)
+ list_for_each_entry(counter, &group_counter->sibling_list, list_entry) {
counter_sched_in(counter, cpuctx, ctx, cpu);
+ was_group = 1;
+ }
+
+ return was_group;
}
/*
@@ -416,7 +421,12 @@
if (counter->cpu != -1 && counter->cpu != cpu)
continue;
- group_sched_in(counter, cpuctx, ctx, cpu);
+ /*
+ * If we scheduled in a group atomically and
+ * exclusively, break out:
+ */
+ if (group_sched_in(counter, cpuctx, ctx, cpu))
+ break;
}
spin_unlock(&ctx->lock);