linux-kernel - [tip: perf/core] perf/core: Merge struct pmu::pmu_disable_count into struct perf_cpu_pmu_context::pmu_disable

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Message-ID: <174107862346.14745.5576020958152188502.tip-bot2@tip-bot2>
Date: Tue, 04 Mar 2025 08:57:03 -0000
From: "tip-bot2 for Peter Zijlstra" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: "Peter Zijlstra (Intel)" <peterz@...radead.org>,
 Ingo Molnar <mingo@...nel.org>, Ravi Bangoria <ravi.bangoria@....com>,
 x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [tip: perf/core] perf/core: Merge struct pmu::pmu_disable_count into
 struct perf_cpu_pmu_context::pmu_disable_count

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

Commit-ID:     4baeb0687abf5eca3f7ab8b147c27cce82ec49ea
Gitweb:        https://git.kernel.org/tip/4baeb0687abf5eca3f7ab8b147c27cce82ec49ea
Author:        Peter Zijlstra <peterz@...radead.org>
AuthorDate:    Mon, 04 Nov 2024 14:39:18 +01:00
Committer:     Ingo Molnar <mingo@...nel.org>
CommitterDate: Tue, 04 Mar 2025 09:42:47 +01:00

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) <peterz@...radead.org>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Reviewed-by: Ravi Bangoria <ravi.bangoria@....com>
Link: https://lore.kernel.org/r/20241104135518.518730578@infradead.org
---
 include/linux/perf_event.h |  2 +-
 kernel/events/core.c       | 12 ++++--------
 2 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 8c0117b..5f293e6 100644
--- a/include/linux/perf_event.h
+++ b/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;
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 348a379..8321b71 100644
--- a/kernel/events/core.c
+++ b/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;