perf: Round robin flexible groups of events using list_rotate_left()
This is more proper that doing it through a list_for_each_entry()
that breaks after the first entry.
v2: Don't rotate pinned groups as its not needed to time share
them.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index c9f8a75..bbebe28 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -1454,25 +1454,16 @@
*/
static void rotate_ctx(struct perf_event_context *ctx)
{
- struct perf_event *event;
-
if (!ctx->nr_events)
return;
raw_spin_lock(&ctx->lock);
- /*
- * Rotate the first entry last (works just fine for group events too):
- */
- perf_disable();
- list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
- list_move_tail(&event->group_entry, &ctx->pinned_groups);
- break;
- }
- list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
- list_move_tail(&event->group_entry, &ctx->flexible_groups);
- break;
- }
+ /* Rotate the first entry last of non-pinned groups */
+ perf_disable();
+
+ list_rotate_left(&ctx->flexible_groups);
+
perf_enable();
raw_spin_unlock(&ctx->lock);
