[tip: perf/core] perf/x86: Add a x86_pmu::limit_period static_call

[tip-bot2 for Peter Zijlstra]

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     08b3068fab207e3c7d79799d434e1d648524cac6
Gitweb:        https://git.kernel.org/tip/08b3068fab207e3c7d79799d434e1d648524cac6
Author:        Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate:    Tue, 10 May 2022 21:28:18 +02:00
Committer:     Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Wed, 07 Sep 2022 21:54:03 +02:00

perf/x86: Add a x86_pmu::limit_period static_call

Avoid a branch and indirect call.

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/20220829101321.640658334@xxxxxxxxxxxxx
---
 arch/x86/events/core.c |  9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 1e90bc7..05830bb 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -72,8 +72,9 @@ DEFINE_STATIC_CALL_NULL(x86_pmu_add,  *x86_pmu.add);
 DEFINE_STATIC_CALL_NULL(x86_pmu_del,  *x86_pmu.del);
 DEFINE_STATIC_CALL_NULL(x86_pmu_read, *x86_pmu.read);
 
-DEFINE_STATIC_CALL_NULL(x86_pmu_set_period, *x86_pmu.set_period);
-DEFINE_STATIC_CALL_NULL(x86_pmu_update,     *x86_pmu.update);
+DEFINE_STATIC_CALL_NULL(x86_pmu_set_period,   *x86_pmu.set_period);
+DEFINE_STATIC_CALL_NULL(x86_pmu_update,       *x86_pmu.update);
+DEFINE_STATIC_CALL_NULL(x86_pmu_limit_period, *x86_pmu.limit_period);
 
 DEFINE_STATIC_CALL_NULL(x86_pmu_schedule_events,       *x86_pmu.schedule_events);
 DEFINE_STATIC_CALL_NULL(x86_pmu_get_event_constraints, *x86_pmu.get_event_constraints);
@@ -1396,8 +1397,7 @@ int x86_perf_event_set_period(struct perf_event *event)
 	if (left > x86_pmu.max_period)
 		left = x86_pmu.max_period;
 
-	if (x86_pmu.limit_period)
-		x86_pmu.limit_period(event, &left);
+	static_call_cond(x86_pmu_limit_period)(event, &left);
 
 	this_cpu_write(pmc_prev_left[idx], left);
 
@@ -2024,6 +2024,7 @@ static void x86_pmu_static_call_update(void)
 
 	static_call_update(x86_pmu_set_period, x86_pmu.set_period);
 	static_call_update(x86_pmu_update, x86_pmu.update);
+	static_call_update(x86_pmu_limit_period, x86_pmu.limit_period);
 
 	static_call_update(x86_pmu_schedule_events, x86_pmu.schedule_events);
 	static_call_update(x86_pmu_get_event_constraints, x86_pmu.get_event_constraints);