perf/core: Merge struct pmu::pmu_disable_count into struct perf_cpu_pmu_context::pmu_disable_count

Because it makes no sense to have two per-cpu allocations per pmu.

Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Reviewed-by: Ravi Bangoria <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: Peter Zijlstra

include/linux/perf_event.h

@@ -343,7 +343,6 @@ struct pmu {
 	 */
 	unsigned int			scope;
 
-	int __percpu			*pmu_disable_count;
 	struct perf_cpu_pmu_context __percpu *cpu_pmu_context;
 	atomic_t			exclusive_cnt; /* < 0: cpu; > 0: tsk */
 	int				task_ctx_nr;
@@ -1031,6 +1030,7 @@ struct perf_cpu_pmu_context {
 
 	int				active_oncpu;
 	int				exclusive;
+	int				pmu_disable_count;
 
 	raw_spinlock_t			hrtimer_lock;
 	struct hrtimer			hrtimer;

kernel/events/core.c

@@ -1219,21 +1219,22 @@ static int perf_mux_hrtimer_restart_ipi(void *arg)
 
 void perf_pmu_disable(struct pmu *pmu)
 {
-	int *count = this_cpu_ptr(pmu->pmu_disable_count);
+	int *count = &this_cpu_ptr(pmu->cpu_pmu_context)->pmu_disable_count;
 	if (!(*count)++)
 		pmu->pmu_disable(pmu);
 }
 
 void perf_pmu_enable(struct pmu *pmu)
 {
-	int *count = this_cpu_ptr(pmu->pmu_disable_count);
+	int *count = &this_cpu_ptr(pmu->cpu_pmu_context)->pmu_disable_count;
 	if (!--(*count))
 		pmu->pmu_enable(pmu);
 }
 
 static void perf_assert_pmu_disabled(struct pmu *pmu)
 {
-	WARN_ON_ONCE(*this_cpu_ptr(pmu->pmu_disable_count) == 0);
+	int *count = &this_cpu_ptr(pmu->cpu_pmu_context)->pmu_disable_count;
+	WARN_ON_ONCE(*count == 0);
 }
 
 static inline void perf_pmu_read(struct perf_event *event)
@@ -11906,7 +11907,6 @@ static bool idr_cmpxchg(struct idr *idr, unsigned long id, void *old, void *new)
 
 static void perf_pmu_free(struct pmu *pmu)
 {
-	free_percpu(pmu->pmu_disable_count);
 	if (pmu_bus_running && pmu->dev && pmu->dev != PMU_NULL_DEV) {
 		if (pmu->nr_addr_filters)
 			device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
@@ -11925,10 +11925,6 @@ int perf_pmu_register(struct pmu *_pmu, const char *name, int type)
 	struct pmu *pmu __free(pmu_unregister) = _pmu;
 	guard(mutex)(&pmus_lock);
 
-	pmu->pmu_disable_count = alloc_percpu(int);
-	if (!pmu->pmu_disable_count)
-		return -ENOMEM;
-
 	if (WARN_ONCE(!name, "Can not register anonymous pmu.\n"))
 		return -EINVAL;