perf/core: Optimize perf_adjust_freq_unthr_context()

It was unnecessarily disabling and enabling PMUs for each event.  It
should be done at PMU level.  Add pmu_ctx->nr_freq counter to check it
at each PMU.  As PMU context has separate active lists for pinned group
and flexible group, factor out a new function to do the job.

Another minor optimization is that it can skip PMUs w/ CAP_NO_INTERRUPT
even if it needs to unthrottle sampling events.

Signed-off-by: Namhyung Kim <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Tested-by: Mingwei Zhang <[email protected]>
Reviewed-by: Ian Rogers <[email protected]>
Reviewed-by: Kan Liang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

1 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index d2a15c0c6f8a..3e33b366347a 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -883,6 +883,7 @@ struct perf_event_pmu_context {
 
 	unsigned int			nr_events;
 	unsigned int			nr_cgroups;
+	unsigned int			nr_freq;
 
 	atomic_t			refcount; /* event <-> epc */
 	struct rcu_head			rcu_head;
@@ -897,6 +898,11 @@ struct perf_event_pmu_context {
 	int				rotate_necessary;
 };
 
+static inline bool perf_pmu_ctx_is_active(struct perf_event_pmu_context *epc)
+{
+	return !list_empty(&epc->flexible_active) || !list_empty(&epc->pinned_active);
+}
+
 struct perf_event_groups {
 	struct rb_root	tree;
 	u64		index;