[PATCH v3 2/9] perf mem: Introduce weak function perf_mem_events__ptr()

From: Leo Yan <hidden>
Date: 2020-10-28 23:21:31
Also in: lkml
Subsystem: performance events subsystem, the rest · Maintainers: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Linus Torvalds

Different architectures might use different event or different event
parameters for memory profiling, this patch introduces weak function
perf_mem_events__ptr(), which allows to return back architecture
specific memory event.

Since the variable 'perf_mem_events' can be only accessed by the
function perf_mem_events__ptr(), marks the variable as 'static', this
allows the architectures to define its own memory event array.

Signed-off-by: Leo Yan <redacted>
---
 tools/perf/builtin-c2c.c     | 18 ++++++++++++------
 tools/perf/builtin-mem.c     | 21 ++++++++++++++-------
 tools/perf/util/mem-events.c | 26 +++++++++++++++++++-------
 tools/perf/util/mem-events.h |  2 +-
 4 files changed, 46 insertions(+), 21 deletions(-)

diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c
index d5bea5d3cd51..4d1a08e38233 100644
--- a/tools/perf/builtin-c2c.c
+++ b/tools/perf/builtin-c2c.c

@@ -2867,6 +2867,7 @@ static int perf_c2c__record(int argc, const char **argv)
 	int ret;
 	bool all_user = false, all_kernel = false;
 	bool event_set = false;
+	struct perf_mem_event *e;
 	struct option options[] = {
 	OPT_CALLBACK('e', "event", &event_set, "event",
 		     "event selector. Use 'perf c2c record -e list' to list available events",

@@ -2894,11 +2895,15 @@ static int perf_c2c__record(int argc, const char **argv)
 	rec_argv[i++] = "record";
 
 	if (!event_set) {
-		perf_mem_events[PERF_MEM_EVENTS__LOAD].record  = true;
-		perf_mem_events[PERF_MEM_EVENTS__STORE].record = true;
+		e = perf_mem_events__ptr(PERF_MEM_EVENTS__LOAD);
+		e->record = true;
+
+		e = perf_mem_events__ptr(PERF_MEM_EVENTS__STORE);
+		e->record = true;
 	}
 
-	if (perf_mem_events[PERF_MEM_EVENTS__LOAD].record)
+	e = perf_mem_events__ptr(PERF_MEM_EVENTS__LOAD);
+	if (e->record)
 		rec_argv[i++] = "-W";
 
 	rec_argv[i++] = "-d";

@@ -2906,12 +2911,13 @@ static int perf_c2c__record(int argc, const char **argv)
 	rec_argv[i++] = "--sample-cpu";
 
 	for (j = 0; j < PERF_MEM_EVENTS__MAX; j++) {
-		if (!perf_mem_events[j].record)
+		e = perf_mem_events__ptr(j);
+		if (!e->record)
 			continue;
 
-		if (!perf_mem_events[j].supported) {
+		if (!e->supported) {
 			pr_err("failed: event '%s' not supported\n",
-			       perf_mem_events[j].name);
+			       perf_mem_events__name(j));
 			free(rec_argv);
 			return -1;
 		}

diff --git a/tools/perf/builtin-mem.c b/tools/perf/builtin-mem.c
index 3523279af6af..9a7df8d01296 100644
--- a/tools/perf/builtin-mem.c
+++ b/tools/perf/builtin-mem.c

@@ -64,6 +64,7 @@ static int __cmd_record(int argc, const char **argv, struct perf_mem *mem)
 	const char **rec_argv;
 	int ret;
 	bool all_user = false, all_kernel = false;
+	struct perf_mem_event *e;
 	struct option options[] = {
 	OPT_CALLBACK('e', "event", &mem, "event",
 		     "event selector. use 'perf mem record -e list' to list available events",

@@ -86,13 +87,18 @@ static int __cmd_record(int argc, const char **argv, struct perf_mem *mem)
 
 	rec_argv[i++] = "record";
 
-	if (mem->operation & MEM_OPERATION_LOAD)
-		perf_mem_events[PERF_MEM_EVENTS__LOAD].record = true;
+	if (mem->operation & MEM_OPERATION_LOAD) {
+		e = perf_mem_events__ptr(PERF_MEM_EVENTS__LOAD);
+		e->record = true;
+	}
 
-	if (mem->operation & MEM_OPERATION_STORE)
-		perf_mem_events[PERF_MEM_EVENTS__STORE].record = true;
+	if (mem->operation & MEM_OPERATION_STORE) {
+		e = perf_mem_events__ptr(PERF_MEM_EVENTS__STORE);
+		e->record = true;
+	}
 
-	if (perf_mem_events[PERF_MEM_EVENTS__LOAD].record)
+	e = perf_mem_events__ptr(PERF_MEM_EVENTS__LOAD);
+	if (e->record)
 		rec_argv[i++] = "-W";
 
 	rec_argv[i++] = "-d";

@@ -101,10 +107,11 @@ static int __cmd_record(int argc, const char **argv, struct perf_mem *mem)
 		rec_argv[i++] = "--phys-data";
 
 	for (j = 0; j < PERF_MEM_EVENTS__MAX; j++) {
-		if (!perf_mem_events[j].record)
+		e = perf_mem_events__ptr(j);
+		if (!e->record)
 			continue;
 
-		if (!perf_mem_events[j].supported) {
+		if (!e->supported) {
 			pr_err("failed: event '%s' not supported\n",
 			       perf_mem_events__name(j));
 			free(rec_argv);

diff --git a/tools/perf/util/mem-events.c b/tools/perf/util/mem-events.c
index 35c8d175a9d2..7a5a0d699e27 100644
--- a/tools/perf/util/mem-events.c
+++ b/tools/perf/util/mem-events.c

@@ -17,7 +17,7 @@ unsigned int perf_mem_events__loads_ldlat = 30;
 
 #define E(t, n, s) { .tag = t, .name = n, .sysfs_name = s }
 
-struct perf_mem_event perf_mem_events[PERF_MEM_EVENTS__MAX] = {
+static struct perf_mem_event perf_mem_events[PERF_MEM_EVENTS__MAX] = {
 	E("ldlat-loads",	"cpu/mem-loads,ldlat=%u/P",	"cpu/events/mem-loads"),
 	E("ldlat-stores",	"cpu/mem-stores/P",		"cpu/events/mem-stores"),
 };

@@ -28,19 +28,31 @@ struct perf_mem_event perf_mem_events[PERF_MEM_EVENTS__MAX] = {
 static char mem_loads_name[100];
 static bool mem_loads_name__init;
 
+struct perf_mem_event * __weak perf_mem_events__ptr(int i)
+{
+	if (i >= PERF_MEM_EVENTS__MAX)
+		return NULL;
+
+	return &perf_mem_events[i];
+}
+
 char * __weak perf_mem_events__name(int i)
 {
+	struct perf_mem_event *e = perf_mem_events__ptr(i);
+
+	if (!e)
+		return NULL;
+
 	if (i == PERF_MEM_EVENTS__LOAD) {
 		if (!mem_loads_name__init) {
 			mem_loads_name__init = true;
 			scnprintf(mem_loads_name, sizeof(mem_loads_name),
-				  perf_mem_events[i].name,
-				  perf_mem_events__loads_ldlat);
+				  e->name, perf_mem_events__loads_ldlat);
 		}
 		return mem_loads_name;
 	}
 
-	return (char *)perf_mem_events[i].name;
+	return (char *)e->name;
 }
 
 int perf_mem_events__parse(const char *str)

@@ -61,7 +73,7 @@ int perf_mem_events__parse(const char *str)
 
 	while (tok) {
 		for (j = 0; j < PERF_MEM_EVENTS__MAX; j++) {
-			struct perf_mem_event *e = &perf_mem_events[j];
+			struct perf_mem_event *e = perf_mem_events__ptr(j);
 
 			if (strstr(e->tag, tok))
 				e->record = found = true;

@@ -90,7 +102,7 @@ int perf_mem_events__init(void)
 
 	for (j = 0; j < PERF_MEM_EVENTS__MAX; j++) {
 		char path[PATH_MAX];
-		struct perf_mem_event *e = &perf_mem_events[j];
+		struct perf_mem_event *e = perf_mem_events__ptr(j);
 		struct stat st;
 
 		scnprintf(path, PATH_MAX, "%s/devices/%s",

@@ -108,7 +120,7 @@ void perf_mem_events__list(void)
 	int j;
 
 	for (j = 0; j < PERF_MEM_EVENTS__MAX; j++) {
-		struct perf_mem_event *e = &perf_mem_events[j];
+		struct perf_mem_event *e = perf_mem_events__ptr(j);
 
 		fprintf(stderr, "%-13s%-*s%s\n",
 			e->tag,

diff --git a/tools/perf/util/mem-events.h b/tools/perf/util/mem-events.h
index 904dad34f7f7..726a9c8103e4 100644
--- a/tools/perf/util/mem-events.h
+++ b/tools/perf/util/mem-events.h

@@ -31,13 +31,13 @@ enum {
 	PERF_MEM_EVENTS__MAX,
 };
 
-extern struct perf_mem_event perf_mem_events[PERF_MEM_EVENTS__MAX];
 extern unsigned int perf_mem_events__loads_ldlat;
 
 int perf_mem_events__parse(const char *str);
 int perf_mem_events__init(void);
 
 char *perf_mem_events__name(int i);
+struct perf_mem_event *perf_mem_events__ptr(int i);
 
 void perf_mem_events__list(void);

-- 
2.17.1


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