[PATCH v3 14/17] perf intel-tpebs: Use DEFINE_MUTEX for tpebs_mtx
From: Ian Rogers
Date: Fri Oct 16 2026 - 13:41:57 EST
Replace tpebs_mtx_get() and its pthread_once() initialization helper
tpebs_init() with DEFINE_MUTEX(tpebs_mtx) and static initializers for
control_fd and ack_fd.
Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
tools/perf/util/intel-tpebs.c | 75 ++++++++++++++---------------------
1 file changed, 30 insertions(+), 45 deletions(-)
diff --git a/tools/perf/util/intel-tpebs.c b/tools/perf/util/intel-tpebs.c
index b81831f5e5a4..57e08476a13d 100644
--- a/tools/perf/util/intel-tpebs.c
+++ b/tools/perf/util/intel-tpebs.c
@@ -36,11 +36,11 @@
bool tpebs_recording;
enum tpebs_mode tpebs_mode;
+static DEFINE_MUTEX(tpebs_mtx);
static LIST_HEAD(tpebs_results);
static pthread_t tpebs_reader_thread;
static struct child_process tpebs_cmd;
-static int control_fd[2], ack_fd[2];
-static struct mutex tpebs_mtx;
+static int control_fd[2] = { -1, -1 }, ack_fd[2] = { -1, -1 };
static bool tpebs_stopping;
struct tpebs_retire_lat {
@@ -57,23 +57,8 @@ struct tpebs_retire_lat {
bool started;
};
-static void tpebs_init(void)
-{
- mutex_init(&tpebs_mtx);
- control_fd[0] = control_fd[1] = -1;
- ack_fd[0] = ack_fd[1] = -1;
-}
-
-static struct mutex *tpebs_mtx_get(void)
-{
- static pthread_once_t tpebs_once = PTHREAD_ONCE_INIT;
-
- pthread_once(&tpebs_once, tpebs_init);
- return &tpebs_mtx;
-}
-
static struct tpebs_retire_lat *tpebs_retire_lat__find(struct evsel *evsel)
- __must_hold(tpebs_mtx_get());
+ __must_hold(&tpebs_mtx);
static int evsel__tpebs_start_perf_record(struct evsel *evsel)
{
@@ -200,19 +185,19 @@ static int process_sample_event(const struct perf_tool *tool __maybe_unused,
{
struct tpebs_retire_lat *t;
- mutex_lock(tpebs_mtx_get());
+ mutex_lock(&tpebs_mtx);
if (tpebs_cmd.pid == 0) {
/* Record has terminated. */
- mutex_unlock(tpebs_mtx_get());
+ mutex_unlock(&tpebs_mtx);
return 0;
}
t = tpebs_retire_lat__find(sample->evsel);
if (!t) {
- mutex_unlock(tpebs_mtx_get());
+ mutex_unlock(&tpebs_mtx);
return -EINVAL;
}
if (should_ignore_sample(sample, t)) {
- mutex_unlock(tpebs_mtx_get());
+ mutex_unlock(&tpebs_mtx);
return 0;
}
/*
@@ -222,7 +207,7 @@ static int process_sample_event(const struct perf_tool *tool __maybe_unused,
*/
t->last = sample->weight3;
update_stats(&t->stats, sample->weight3);
- mutex_unlock(tpebs_mtx_get());
+ mutex_unlock(&tpebs_mtx);
return 0;
}
@@ -252,7 +237,7 @@ static void *__sample_reader(void *arg)
return NULL;
}
-static int tpebs_send_record_cmd(const char *msg) __must_hold(tpebs_mtx_get())
+static int tpebs_send_record_cmd(const char *msg) __must_hold(&tpebs_mtx)
{
struct pollfd pollfd = { .events = POLLIN, };
int ret, len, retries = 0;
@@ -266,7 +251,7 @@ static int tpebs_send_record_cmd(const char *msg) __must_hold(tpebs_mtx_get())
* Let go of the lock while sending/receiving as blocking can starve the
* sample reading thread.
*/
- mutex_unlock(tpebs_mtx_get());
+ mutex_unlock(&tpebs_mtx);
/* Send perf record command.*/
len = strlen(msg);
@@ -322,14 +307,14 @@ static int tpebs_send_record_cmd(const char *msg) __must_hold(tpebs_mtx_get())
pr_err("tpebs: perf record control ack failed\n");
out:
/* Re-take lock as expected by caller. */
- mutex_lock(tpebs_mtx_get());
+ mutex_lock(&tpebs_mtx);
return ret;
}
/*
* tpebs_stop - stop the sample data read thread and the perf record process.
*/
-static int tpebs_stop(void) __must_hold(tpebs_mtx_get())
+static int tpebs_stop(void) __must_hold(&tpebs_mtx)
{
int ret = 0;
@@ -345,9 +330,9 @@ static int tpebs_stop(void) __must_hold(tpebs_mtx_get())
tpebs_send_record_cmd(EVLIST_CTL_CMD_STOP_TAG);
tpebs_cmd.pid = 0;
reader_thread = tpebs_reader_thread;
- mutex_unlock(tpebs_mtx_get());
+ mutex_unlock(&tpebs_mtx);
pthread_join(reader_thread, NULL);
- mutex_lock(tpebs_mtx_get());
+ mutex_lock(&tpebs_mtx);
if (control_fd[0] >= 0) {
close(control_fd[0]);
control_fd[0] = -1;
@@ -483,20 +468,20 @@ static int evsel__tpebs_prepare(struct evsel *evsel)
struct evsel *pos;
struct tpebs_retire_lat *tpebs_event;
- mutex_lock(tpebs_mtx_get());
+ mutex_lock(&tpebs_mtx);
tpebs_event = tpebs_retire_lat__find(evsel);
if (tpebs_event) {
/* evsel, or an identically named one, was already prepared. */
- mutex_unlock(tpebs_mtx_get());
+ mutex_unlock(&tpebs_mtx);
return 0;
}
tpebs_event = tpebs_retire_lat__new(evsel);
if (!tpebs_event) {
- mutex_unlock(tpebs_mtx_get());
+ mutex_unlock(&tpebs_mtx);
return -ENOMEM;
}
list_add_tail(&tpebs_event->nd, &tpebs_results);
- mutex_unlock(tpebs_mtx_get());
+ mutex_unlock(&tpebs_mtx);
/*
* Eagerly prepare all other evsels on the list to try to ensure that by
@@ -530,9 +515,9 @@ int evsel__tpebs_open(struct evsel *evsel)
if (!tpebs_recording)
return 0;
- mutex_lock(tpebs_mtx_get());
+ mutex_lock(&tpebs_mtx);
if (tpebs_stopping) {
- mutex_unlock(tpebs_mtx_get());
+ mutex_unlock(&tpebs_mtx);
return -EBUSY;
}
/* Only start the events once. */
@@ -542,17 +527,17 @@ int evsel__tpebs_open(struct evsel *evsel)
t = tpebs_retire_lat__find(evsel);
valid = t && t->started;
- mutex_unlock(tpebs_mtx_get());
+ mutex_unlock(&tpebs_mtx);
/* May fail as the event wasn't started. */
return valid ? 0 : -EBUSY;
}
- mutex_unlock(tpebs_mtx_get());
+ mutex_unlock(&tpebs_mtx);
ret = evsel__tpebs_prepare(evsel);
if (ret)
return ret;
- mutex_lock(tpebs_mtx_get());
+ mutex_lock(&tpebs_mtx);
if (tpebs_stopping || tpebs_cmd.pid != 0) {
ret = -EBUSY;
goto out;
@@ -624,7 +609,7 @@ int evsel__tpebs_open(struct evsel *evsel)
}
}
}
- mutex_unlock(tpebs_mtx_get());
+ mutex_unlock(&tpebs_mtx);
return ret;
}
@@ -644,7 +629,7 @@ int evsel__tpebs_read(struct evsel *evsel, int cpu_map_idx, int thread)
count = perf_counts(evsel->counts, cpu_map_idx, thread);
- mutex_lock(tpebs_mtx_get());
+ mutex_lock(&tpebs_mtx);
t = tpebs_retire_lat__find(evsel);
/*
* If reading the first tpebs result, send a ping to the record
@@ -653,10 +638,10 @@ int evsel__tpebs_read(struct evsel *evsel, int cpu_map_idx, int thread)
*/
if (t && &t->nd == tpebs_results.next) {
ret = tpebs_send_record_cmd(EVLIST_CTL_CMD_PING_TAG);
- mutex_unlock(tpebs_mtx_get());
+ mutex_unlock(&tpebs_mtx);
if (ret)
return ret;
- mutex_lock(tpebs_mtx_get());
+ mutex_lock(&tpebs_mtx);
}
if (t == NULL || t->stats.n == 0) {
/* No sample data, use default. */
@@ -695,7 +680,7 @@ int evsel__tpebs_read(struct evsel *evsel, int cpu_map_idx, int thread)
break;
}
}
- mutex_unlock(tpebs_mtx_get());
+ mutex_unlock(&tpebs_mtx);
if (old_count) {
count->val = old_count->val + val;
@@ -720,7 +705,7 @@ void evsel__tpebs_close(struct evsel *evsel)
{
struct tpebs_retire_lat *t;
- mutex_lock(tpebs_mtx_get());
+ mutex_lock(&tpebs_mtx);
t = tpebs_retire_lat__find(evsel);
if (t) {
list_del_init(&t->nd);
@@ -729,5 +714,5 @@ void evsel__tpebs_close(struct evsel *evsel)
if (list_empty(&tpebs_results))
tpebs_stop();
}
- mutex_unlock(tpebs_mtx_get());
+ mutex_unlock(&tpebs_mtx);
}
--
2.56.0.212.g129ede20d9-goog