[PATCH 07/30] perf tools: Add reference counting for thread_map object

[Jiri Olsa <jolsa@kernel.org>]

Adding refference counting for thread_map object, so
it could be easily shared among other objects.

Using thread_map__put instead thread_map__delete and making
thread_map__delete static.

Link: http://lkml.kernel.org/n/tip-myadl53clbkjvzeqolwp95w0@git.kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 tools/perf/tests/code-reading.c            |  2 +-
 tools/perf/tests/keep-tracking.c           |  2 +-
 tools/perf/tests/mmap-basic.c              |  2 +-
 tools/perf/tests/mmap-thread-lookup.c      |  2 +-
 tools/perf/tests/openat-syscall-all-cpus.c |  2 +-
 tools/perf/tests/openat-syscall.c          |  2 +-
 tools/perf/tests/switch-tracking.c         |  2 +-
 tools/perf/util/evlist.c                   |  4 ++--
 tools/perf/util/python.c                   |  2 +-
 tools/perf/util/thread_map.c               | 30 ++++++++++++++++++++++++++----
 tools/perf/util/thread_map.h               |  7 +++++--
 11 files changed, 41 insertions(+), 16 deletions(-)

diff --git a/tools/perf/tests/code-reading.c b/tools/perf/tests/code-reading.c
index 86d17d2e9e50..7dcd2c3d865f 100644
--- a/tools/perf/tests/code-reading.c
+++ b/tools/perf/tests/code-reading.c
@@ -546,7 +546,7 @@ out_err:
 		perf_evlist__delete(evlist);
 	} else {
 		cpu_map__put(cpus);
-		thread_map__delete(threads);
+		thread_map__put(threads);
 	}
 	machines__destroy_kernel_maps(&machines);
 	machine__delete_threads(machine);
diff --git a/tools/perf/tests/keep-tracking.c b/tools/perf/tests/keep-tracking.c
index a330235cefc0..4d4b9837b630 100644
--- a/tools/perf/tests/keep-tracking.c
+++ b/tools/perf/tests/keep-tracking.c
@@ -145,7 +145,7 @@ out_err:
 		perf_evlist__delete(evlist);
 	} else {
 		cpu_map__put(cpus);
-		thread_map__delete(threads);
+		thread_map__put(threads);
 	}
 
 	return err;
diff --git a/tools/perf/tests/mmap-basic.c b/tools/perf/tests/mmap-basic.c
index 5a9ef5833452..666b67a4df9d 100644
--- a/tools/perf/tests/mmap-basic.c
+++ b/tools/perf/tests/mmap-basic.c
@@ -142,6 +142,6 @@ out_delete_evlist:
 out_free_cpus:
 	cpu_map__put(cpus);
 out_free_threads:
-	thread_map__delete(threads);
+	thread_map__put(threads);
 	return err;
 }
diff --git a/tools/perf/tests/mmap-thread-lookup.c b/tools/perf/tests/mmap-thread-lookup.c
index 264e215c0d36..412a41eb3f81 100644
--- a/tools/perf/tests/mmap-thread-lookup.c
+++ b/tools/perf/tests/mmap-thread-lookup.c
@@ -143,7 +143,7 @@ static int synth_process(struct machine *machine)
 						perf_event__process,
 						machine, 0);
 
-	thread_map__delete(map);
+	thread_map__put(map);
 	return err;
 }
 
diff --git a/tools/perf/tests/openat-syscall-all-cpus.c b/tools/perf/tests/openat-syscall-all-cpus.c
index e34dfdf96b5a..8801983a38f0 100644
--- a/tools/perf/tests/openat-syscall-all-cpus.c
+++ b/tools/perf/tests/openat-syscall-all-cpus.c
@@ -110,6 +110,6 @@ out_close_fd:
 out_evsel_delete:
 	perf_evsel__delete(evsel);
 out_thread_map_delete:
-	thread_map__delete(threads);
+	thread_map__put(threads);
 	return err;
 }
diff --git a/tools/perf/tests/openat-syscall.c b/tools/perf/tests/openat-syscall.c
index 9f9491bb8e48..bdfa1f446681 100644
--- a/tools/perf/tests/openat-syscall.c
+++ b/tools/perf/tests/openat-syscall.c
@@ -56,6 +56,6 @@ out_close_fd:
 out_evsel_delete:
 	perf_evsel__delete(evsel);
 out_thread_map_delete:
-	thread_map__delete(threads);
+	thread_map__put(threads);
 	return err;
 }
diff --git a/tools/perf/tests/switch-tracking.c b/tools/perf/tests/switch-tracking.c
index 1b06122beb76..e698742d4fec 100644
--- a/tools/perf/tests/switch-tracking.c
+++ b/tools/perf/tests/switch-tracking.c
@@ -561,7 +561,7 @@ out:
 		perf_evlist__delete(evlist);
 	} else {
 		cpu_map__put(cpus);
-		thread_map__delete(threads);
+		thread_map__put(threads);
 	}
 
 	return err;
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index bd747215caa4..f7d80ca58136 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -115,7 +115,7 @@ void perf_evlist__delete(struct perf_evlist *evlist)
 	perf_evlist__munmap(evlist);
 	perf_evlist__close(evlist);
 	cpu_map__put(evlist->cpus);
-	thread_map__delete(evlist->threads);
+	thread_map__put(evlist->threads);
 	evlist->cpus = NULL;
 	evlist->threads = NULL;
 	perf_evlist__purge(evlist);
@@ -1104,7 +1104,7 @@ int perf_evlist__create_maps(struct perf_evlist *evlist, struct target *target)
 	return 0;
 
 out_delete_threads:
-	thread_map__delete(evlist->threads);
+	thread_map__put(evlist->threads);
 	evlist->threads = NULL;
 	return -1;
 }
diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
index b106d56df240..626422eda727 100644
--- a/tools/perf/util/python.c
+++ b/tools/perf/util/python.c
@@ -453,7 +453,7 @@ static int pyrf_thread_map__init(struct pyrf_thread_map *pthreads,
 
 static void pyrf_thread_map__delete(struct pyrf_thread_map *pthreads)
 {
-	thread_map__delete(pthreads->threads);
+	thread_map__put(pthreads->threads);
 	pthreads->ob_type->tp_free((PyObject*)pthreads);
 }
 
diff --git a/tools/perf/util/thread_map.c b/tools/perf/util/thread_map.c
index f7a49a693d27..584fa978e50a 100644
--- a/tools/perf/util/thread_map.c
+++ b/tools/perf/util/thread_map.c
@@ -9,6 +9,7 @@
 #include "strlist.h"
 #include <string.h>
 #include <api/fs/fs.h>
+#include "asm/bug.h"
 #include "thread_map.h"
 #include "util.h"
 #include "debug.h"
@@ -89,6 +90,7 @@ struct thread_map *thread_map__new_by_pid(pid_t pid)
 			comm_init(threads, i);
 		}
 		threads->nr = items;
+		atomic_set(&threads->refcnt, 1);
 	}
 
 	for (i=0; i<items; i++)
@@ -106,6 +108,7 @@ struct thread_map *thread_map__new_by_tid(pid_t tid)
 		thread_map__pid(threads, 0) = tid;
 		threads->nr		    = 1;
 		comm_init(threads, 0);
+		atomic_set(&threads->refcnt, 1);
 	}
 
 	return threads;
@@ -127,6 +130,7 @@ struct thread_map *thread_map__new_by_uid(uid_t uid)
 		goto out_free_threads;
 
 	threads->nr = 0;
+	atomic_set(&threads->refcnt, 1);
 
 	while (!readdir_r(proc, &dirent, &next) && next) {
 		char *end;
@@ -256,6 +260,8 @@ static struct thread_map *thread_map__new_by_pid_str(const char *pid_str)
 
 out:
 	strlist__delete(slist);
+	if (threads)
+		atomic_set(&threads->refcnt, 1);
 	return threads;
 
 out_free_namelist:
@@ -276,6 +282,7 @@ struct thread_map *thread_map__new_dummy(void)
 		thread_map__pid(threads, 0) = -1;
 		threads->nr		    = 1;
 		comm_init(threads, 0);
+		atomic_set(&threads->refcnt, 1);
 	}
 	return threads;
 }
@@ -319,6 +326,8 @@ static struct thread_map *thread_map__new_by_tid_str(const char *tid_str)
 		comm_init(threads, ntasks - 1);
 	}
 out:
+	if (threads)
+		atomic_set(&threads->refcnt, 1);
 	return threads;
 
 out_free_threads:
@@ -338,16 +347,29 @@ struct thread_map *thread_map__new_str(const char *pid, const char *tid,
 	return thread_map__new_by_tid_str(tid);
 }
 
-void thread_map__delete(struct thread_map *threads)
+static void thread_map__delete(struct thread_map *threads)
 {
-	int i;
-
 	if (threads) {
+		int i;
+
+		WARN_ONCE(atomic_read(&threads->refcnt) != 0,
+			  "thread map refcnt disbalanced\n");
 		for (i = 0; i < threads->nr; i++)
 			free(thread_map__comm(threads, i));
+		free(threads);
 	}
+}
 
-	free(threads);
+struct thread_map *thread_map__get(struct thread_map *map)
+{
+	atomic_inc(&map->refcnt);
+	return map;
+}
+
+void thread_map__put(struct thread_map *map)
+{
+	if (map && atomic_dec_and_test(&map->refcnt))
+		thread_map__delete(map);
 }
 
 size_t thread_map__fprintf(struct thread_map *threads, FILE *fp)
diff --git a/tools/perf/util/thread_map.h b/tools/perf/util/thread_map.h
index 6933f9d316d9..91207cee7294 100644
--- a/tools/perf/util/thread_map.h
+++ b/tools/perf/util/thread_map.h
@@ -3,6 +3,7 @@
 
 #include <sys/types.h>
 #include <stdio.h>
+#include <linux/atomic.h>
 
 struct thread_map_data {
 	pid_t    pid;
@@ -10,6 +11,7 @@ struct thread_map_data {
 };
 
 struct thread_map {
+	atomic_t refcnt;
 	int nr;
 	struct thread_map_data map[];
 };
@@ -23,11 +25,12 @@ struct thread_map *thread_map__new_by_tid(pid_t tid);
 struct thread_map *thread_map__new_by_uid(uid_t uid);
 struct thread_map *thread_map__new(pid_t pid, pid_t tid, uid_t uid);
 
+struct thread_map *thread_map__get(struct thread_map *map);
+void thread_map__put(struct thread_map *map);
+
 struct thread_map *thread_map__new_str(const char *pid,
 		const char *tid, uid_t uid);
 
-void thread_map__delete(struct thread_map *threads);
-
 size_t thread_map__fprintf(struct thread_map *threads, FILE *fp);
 
 static inline int thread_map__nr(struct thread_map *threads)
-- 
1.9.3