tools lib api fs tracing_path: Introduce opendir() method

tip:perf/core tip-bot for Arnaldo Carvalho de Melo 1 participant 1 message May 19, 2018 perf events

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2018-05-19 11:42 UTC #0 lore raw

Commit-ID:  7014e0e3bf9b0d0b6221eb7d2f8a1f690423dd73
Gitweb:     https://git.kernel.org/tip/7014e0e3bf9b0d0b6221eb7d2f8a1f690423dd73
Author:     Arnaldo Carvalho de Melo <[email protected]>
AuthorDate: Thu, 17 May 2018 14:42:39 -0300
Committer:  Arnaldo Carvalho de Melo <[email protected]>
CommitDate: Thu, 17 May 2018 14:50:38 -0300

tools lib api fs tracing_path: Introduce opendir() method

That takes care of using the right call to get the tracing_path directory, the one that will end up calling tracing_path_set() to figure out where tracefs is mounted.

One more step in doing just lazy reading of system structures to reduce the number of operations done unconditionaly at 'perf' start.

Cc Adrian Hunter <[email protected]>

Cc David Ahern <[email protected]>

Cc Jiri Olsa <[email protected]>

Cc Namhyung Kim <[email protected]>

Cc Wang Nan <[email protected]>

Link https://lkml.kernel.org/n/[email protected] open here

Signed-off-by Arnaldo Carvalho de Melo <[email protected]>

---
 tools/lib/api/fs/tracing_path.c | 13 +++++++++++++
 tools/lib/api/fs/tracing_path.h |  3 +++
 tools/perf/tests/parse-events.c |  2 +-
 tools/perf/util/parse-events.c  |  8 ++++----
 4 files changed, 21 insertions(+), 5 deletions(-)

tools/lib/api/fs/tracing_path.c +13 -0

index 9cd282425929..9b451af0721c 100644
@@ -101,6 +101,19 @@ void put_events_file(char *file)
 	free(file);
 }
 
+DIR *tracing_events__opendir(void)
+{
+	DIR *dir = NULL;
+	char *path = get_tracing_file("events");
+
+	if (path) {
+		dir = opendir(path);
+		put_events_file(path);
+	}
+
+	return dir;
+}
+
 int tracing_path__strerror_open_tp(int err, char *buf, size_t size,
 				   const char *sys, const char *name)
 {

tools/lib/api/fs/tracing_path.h +3 -0

index 3b32fb439f12..904d085b2ae7 100644
@@ -3,9 +3,12 @@
 #define __API_FS_TRACING_PATH_H
 
 #include <linux/types.h>
+#include <dirent.h>
 
 extern char tracing_events_path[];
 
+DIR *tracing_events__opendir(void);
+
 void tracing_path_set(const char *mountpoint);
 const char *tracing_path_mount(void);

tools/perf/tests/parse-events.c +1 -1

index 6d57d7082637..b9ebe15afb13 100644
@@ -1323,7 +1323,7 @@ static int count_tracepoints(void)
 	DIR *events_dir;
 	int cnt = 0;
 
-	events_dir = opendir(tracing_events_path);
+	events_dir = tracing_events__opendir();
 
 	TEST_ASSERT_VAL("Can't open events dir", events_dir);

tools/perf/util/parse-events.c +4 -4

index 24668300b327..15eec49e71a1 100644
@@ -191,7 +191,7 @@ struct tracepoint_path *tracepoint_id_to_path(u64 config)
 	char evt_path[MAXPATHLEN];
 	char *dir_path;
 
-	sys_dir = opendir(tracing_events_path);
+	sys_dir = tracing_events__opendir();
 	if (!sys_dir)
 		return NULL;

@@ -578,7 +578,7 @@ static int add_tracepoint_multi_sys(struct list_head *list, int *idx,
 	DIR *events_dir;
 	int ret = 0;
 
-	events_dir = opendir(tracing_events_path);
+	events_dir = tracing_events__opendir();
 	if (!events_dir) {
 		tracepoint_error(err, errno, sys_name, evt_name);
 		return -1;

@@ -2106,7 +2106,7 @@ void print_tracepoint_events(const char *subsys_glob, const char *event_glob,
 	bool evt_num_known = false;
 
 restart:
-	sys_dir = opendir(tracing_events_path);
+	sys_dir = tracing_events__opendir();
 	if (!sys_dir)
 		return;

@@ -2200,7 +2200,7 @@ int is_valid_tracepoint(const char *event_string)
 	char evt_path[MAXPATHLEN];
 	char *dir_path;
 
-	sys_dir = opendir(tracing_events_path);
+	sys_dir = tracing_events__opendir();
 	if (!sys_dir)
 		return 0;