perf: Optimize perf_sched_events() usage

It doesn't make sense to take up-to _4_ references on
perf_sched_events() per event, avoid doing this.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 079eb9fcaaa8a622449747435934cb002b777010..935aefd163546c819f130e490a8a317cca5dfc39 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3491,11 +3491,13 @@ static void unaccount_event_cpu(struct perf_event *event, int cpu)
 
 static void unaccount_event(struct perf_event *event)
 {
+       bool dec = false;
+
        if (event->parent)
                return;
 
        if (event->attach_state & PERF_ATTACH_TASK)
-               static_key_slow_dec_deferred(&perf_sched_events);
+               dec = true;
        if (event->attr.mmap || event->attr.mmap_data)
                atomic_dec(&nr_mmap_events);
        if (event->attr.comm)
@@ -3505,12 +3507,15 @@ static void unaccount_event(struct perf_event *event)
        if (event->attr.freq)
                atomic_dec(&nr_freq_events);
        if (event->attr.context_switch) {
-               static_key_slow_dec_deferred(&perf_sched_events);
+               dec = true;
                atomic_dec(&nr_switch_events);
        }
        if (is_cgroup_event(event))
-               static_key_slow_dec_deferred(&perf_sched_events);
+               dec = true;
        if (has_branch_stack(event))
+               dec = true;
+
+       if (dec)
                static_key_slow_dec_deferred(&perf_sched_events);
 
        unaccount_event_cpu(event, event->cpu);
@@ -7723,11 +7728,13 @@ static void account_event_cpu(struct perf_event *event, int cpu)
 
 static void account_event(struct perf_event *event)
 {
+       bool inc = false;
+
        if (event->parent)
                return;
 
        if (event->attach_state & PERF_ATTACH_TASK)
-               static_key_slow_inc(&perf_sched_events.key);
+               inc = true;
        if (event->attr.mmap || event->attr.mmap_data)
                atomic_inc(&nr_mmap_events);
        if (event->attr.comm)
@@ -7740,11 +7747,14 @@ static void account_event(struct perf_event *event)
        }
        if (event->attr.context_switch) {
                atomic_inc(&nr_switch_events);
-               static_key_slow_inc(&perf_sched_events.key);
+               inc = true;
        }
        if (has_branch_stack(event))
-               static_key_slow_inc(&perf_sched_events.key);
+               inc = true;
        if (is_cgroup_event(event))
+               inc = true;
+
+       if (inc)
                static_key_slow_inc(&perf_sched_events.key);
 
        account_event_cpu(event, event->cpu);