[PATCH v5 25/34] perf pmus: Prefer perf_pmu__scan over perf_pmus__for_each_pmu

From: Ian Rogers <irogers@google.com>
To: Suzuki K Poulose <suzuki.poulose@arm.com>,
	Mike Leach <mike.leach@linaro.org>, Leo Yan <leo.yan@linaro.org>,
	John Garry <john.g.garry@oracle.com>,
	Will Deacon <will@kernel.org>, James Clark <james.clark@arm.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@kernel.org>, Namhyung Kim <namhyung@kernel.org>,
	Ian Rogers <irogers@google.com>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Kajol Jain <kjain@linux.ibm.com>,
	Jing Zhang <renyu.zj@linux.alibaba.com>,
	Kan Liang <kan.liang@linux.intel.com>,
	Zhengjun Xing <zhengjun.xing@linux.intel.com>,
	Ravi Bangoria <ravi.bangoria@amd.com>,
	Madhavan Srinivasan <maddy@linux.ibm.com>,
	Athira Rajeev <atrajeev@linux.vnet.ibm.com>,
	Ming Wang <wangming01@loongson.cn>,
	Huacai Chen <chenhuacai@kernel.org>,
	Sandipan Das <sandipan.das@amd.com>,
	Dmitrii Dolgov <9erthalion6@gmail.com>,
	Sean Christopherson <seanjc@google.com>,
	Ali Saidi <alisaidi@amazon.com>, Rob Herring <robh@kernel.org>,
	Thomas Richter <tmricht@linux.ibm.com>,
	Kang Minchul <tegongkang@gmail.com>,
	linux-kernel@vger.kernel.org, coresight@lists.linaro.org,
	linux-arm-kernel@lists.infradead.org,
	linux-perf-users@vger.kernel.org
Subject: [PATCH v5 25/34] perf pmus: Prefer perf_pmu__scan over perf_pmus__for_each_pmu
Date: Sat, 27 May 2023 00:22:01 -0700	[thread overview]
Message-ID: <20230527072210.2900565-26-irogers@google.com> (raw)
In-Reply-To: <20230527072210.2900565-1-irogers@google.com>

perf_pmus__for_each_pmu doesn't lazily initialize pmus making its use
error prone. Just use perf_pmu__scan as this only impacts
non-performance critical tests.

Signed-off-by: Ian Rogers <irogers@google.com>
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
---
 tools/perf/bench/pmu-scan.c     |  6 ++----
 tools/perf/tests/event_groups.c |  7 ++-----
 tools/perf/tests/parse-events.c | 11 ++++-------
 tools/perf/util/pmus.h          |  2 --
 4 files changed, 8 insertions(+), 18 deletions(-)

diff --git a/tools/perf/bench/pmu-scan.c b/tools/perf/bench/pmu-scan.c
index f0f007843bb8..f4a6c37cbe27 100644
--- a/tools/perf/bench/pmu-scan.c
+++ b/tools/perf/bench/pmu-scan.c
@@ -40,13 +40,11 @@ static struct pmu_scan_result *results;
 
 static int save_result(void)
 {
-	struct perf_pmu *pmu;
+	struct perf_pmu *pmu = NULL;
 	struct list_head *list;
 	struct pmu_scan_result *r;
 
-	perf_pmu__scan(NULL);
-
-	perf_pmus__for_each_pmu(pmu) {
+	while ((pmu = perf_pmu__scan(pmu)) != NULL) {
 		r = realloc(results, (nr_pmus + 1) * sizeof(*r));
 		if (r == NULL)
 			return -ENOMEM;
diff --git a/tools/perf/tests/event_groups.c b/tools/perf/tests/event_groups.c
index 029442b4e9c6..3d9a2b524bba 100644
--- a/tools/perf/tests/event_groups.c
+++ b/tools/perf/tests/event_groups.c
@@ -50,13 +50,10 @@ static int event_open(int type, unsigned long config, int group_fd)
 
 static int setup_uncore_event(void)
 {
-	struct perf_pmu *pmu;
+	struct perf_pmu *pmu = NULL;
 	int i, fd;
 
-	if (list_empty(&pmus))
-		perf_pmu__scan(NULL);
-
-	perf_pmus__for_each_pmu(pmu) {
+	while ((pmu = perf_pmu__scan(pmu)) != NULL) {
 		for (i = 0; i < NR_UNCORE_PMUS; i++) {
 			if (!strcmp(uncore_pmus[i].name, pmu->name)) {
 				pr_debug("Using %s for uncore pmu event\n", pmu->name);
diff --git a/tools/perf/tests/parse-events.c b/tools/perf/tests/parse-events.c
index 72a10bed84fd..277607ede060 100644
--- a/tools/perf/tests/parse-events.c
+++ b/tools/perf/tests/parse-events.c
@@ -108,11 +108,11 @@ static int test__checkevent_raw(struct evlist *evlist)
 	TEST_ASSERT_VAL("wrong number of entries", 0 != evlist->core.nr_entries);
 
 	perf_evlist__for_each_evsel(&evlist->core, evsel) {
-		struct perf_pmu *pmu;
+		struct perf_pmu *pmu = NULL;
 		bool type_matched = false;
 
 		TEST_ASSERT_VAL("wrong config", test_perf_config(evsel, 0x1a));
-		perf_pmus__for_each_pmu(pmu) {
+		while ((pmu = perf_pmu__scan(pmu)) != NULL) {
 			if (pmu->type == evsel->attr.type) {
 				TEST_ASSERT_VAL("PMU type expected once", !type_matched);
 				type_matched = true;
@@ -2243,13 +2243,10 @@ static int test__terms2(struct test_suite *test __maybe_unused, int subtest __ma
 
 static int test__pmu_events(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
 {
-	struct perf_pmu *pmu;
+	struct perf_pmu *pmu = NULL;
 	int ret = TEST_OK;
 
-	if (list_empty(&pmus))
-		perf_pmu__scan(NULL);
-
-	perf_pmus__for_each_pmu(pmu) {
+	while ((pmu = perf_pmu__scan(pmu)) != NULL) {
 		struct stat st;
 		char path[PATH_MAX];
 		struct dirent *ent;
diff --git a/tools/perf/util/pmus.h b/tools/perf/util/pmus.h
index d475e2960c10..257de10788e8 100644
--- a/tools/perf/util/pmus.h
+++ b/tools/perf/util/pmus.h
@@ -5,8 +5,6 @@
 extern struct list_head pmus;
 struct perf_pmu;
 
-#define perf_pmus__for_each_pmu(pmu) list_for_each_entry(pmu, &pmus, list)
-
 const struct perf_pmu *perf_pmus__pmu_for_pmu_filter(const char *str);
 
 #endif /* __PMUS_H */
-- 
2.41.0.rc0.172.g3f132b7071-goog

