[PATCH 3/6] perf tools: Allocate thread map_groups dynamically

[Jiri Olsa]

Moving towards sharing map groups within a process threads.

Because of this we need the map groups to be dynamically
allocated. No other functional change is intended in here.

Adding new interface to get/put map groups:
  thread__map_groups_get
    - allocates map groups for thread

  thread__map_groups_put
    - frees map groups for thread

Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Don Zickus <dzickus@xxxxxxxxxx>
Cc: Corey Ashford <cjashfor@xxxxxxxxxxxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxxxxxxxxxx>
---
 tools/perf/arch/x86/tests/dwarf-unwind.c |  9 +++-
 tools/perf/ui/stdio/hist.c               |  9 +++-
 tools/perf/util/event.c                  | 10 +++-
 tools/perf/util/machine.c                |  6 +--
 tools/perf/util/map.h                    |  1 -
 tools/perf/util/thread.c                 | 86 +++++++++++++++++++++++++++-----
 tools/perf/util/thread.h                 |  8 ++-
 7 files changed, 107 insertions(+), 22 deletions(-)

diff --git a/tools/perf/arch/x86/tests/dwarf-unwind.c b/tools/perf/arch/x86/tests/dwarf-unwind.c
index b602ad9..4e2088c 100644
--- a/tools/perf/arch/x86/tests/dwarf-unwind.c
+++ b/tools/perf/arch/x86/tests/dwarf-unwind.c
@@ -23,7 +23,14 @@ static int sample_ustack(struct perf_sample *sample,
 
 	sp = (unsigned long) regs[PERF_REG_X86_SP];
 
-	map = map_groups__find(&thread->mg, MAP__FUNCTION, (u64) sp);
+	/*
+	 * The generic code (test__dwarf_unwind) synthesizes and
+	 * processes mmap events, so if we get NULL in thread->mg,
+	 * it's bug.
+	 */
+	BUG_ON(!thread->mg);
+
+	map = map_groups__find(thread->mg, MAP__FUNCTION, (u64) sp);
 	if (!map) {
 		pr_debug("failed to get stack map\n");
 		return -1;
diff --git a/tools/perf/ui/stdio/hist.c b/tools/perf/ui/stdio/hist.c
index d59893e..fc318c3 100644
--- a/tools/perf/ui/stdio/hist.c
+++ b/tools/perf/ui/stdio/hist.c
@@ -495,7 +495,14 @@ print_entries:
 			break;
 
 		if (h->ms.map == NULL && verbose > 1) {
-			__map_groups__fprintf_maps(&h->thread->mg,
+			struct map_groups *mg;
+
+			mg = thread__map_groups_get(h->thread);
+			if (!mg) {
+				ret = -ENOMEM;
+				break;
+			}
+			__map_groups__fprintf_maps(mg,
 						   MAP__FUNCTION, verbose, fp);
 			fprintf(fp, "%.10s end\n", graph_dotted_line);
 		}
diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index 9c18b126..bc1da4d 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -699,7 +699,7 @@ void thread__find_addr_map(struct thread *thread,
 			   enum map_type type, u64 addr,
 			   struct addr_location *al)
 {
-	struct map_groups *mg = &thread->mg;
+	struct map_groups *mg;
 	bool load_map = false;
 
 	al->machine = machine;
@@ -719,12 +719,14 @@ void thread__find_addr_map(struct thread *thread,
 		load_map = true;
 	} else if (cpumode == PERF_RECORD_MISC_USER && perf_host) {
 		al->level = '.';
+		mg = thread__map_groups_get(thread);
 	} else if (cpumode == PERF_RECORD_MISC_GUEST_KERNEL && perf_guest) {
 		al->level = 'g';
 		mg = &machine->kmaps;
 		load_map = true;
 	} else if (cpumode == PERF_RECORD_MISC_GUEST_USER && perf_guest) {
 		al->level = 'u';
+		mg = thread__map_groups_get(thread);
 	} else {
 		al->level = 'H';
 		al->map = NULL;
@@ -740,6 +742,12 @@ void thread__find_addr_map(struct thread *thread,
 
 		return;
 	}
+
+	if (mg == NULL) {
+		al->map = NULL;
+		return;
+	}
+
 try_again:
 	al->map = map_groups__find(mg, type, al->addr);
 	if (al->map == NULL) {
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index a53cd0b..d1f06d2 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -1046,8 +1046,7 @@ int machine__process_mmap2_event(struct machine *machine,
 	if (map == NULL)
 		goto out_problem;
 
-	thread__insert_map(thread, map);
-	return 0;
+	return thread__insert_map(thread, map);
 
 out_problem:
 	dump_printf("problem processing PERF_RECORD_MMAP2, skipping event.\n");
@@ -1093,8 +1092,7 @@ int machine__process_mmap_event(struct machine *machine, union perf_event *event
 	if (map == NULL)
 		goto out_problem;
 
-	thread__insert_map(thread, map);
-	return 0;
+	return thread__insert_map(thread, map);
 
 out_problem:
 	dump_printf("problem processing PERF_RECORD_MMAP, skipping event.\n");
diff --git a/tools/perf/util/map.h b/tools/perf/util/map.h
index f00f058..99a6488 100644
--- a/tools/perf/util/map.h
+++ b/tools/perf/util/map.h
@@ -202,5 +202,4 @@ struct map *map_groups__find_by_name(struct map_groups *mg,
 				     enum map_type type, const char *name);
 
 void map_groups__flush(struct map_groups *mg);
-
 #endif /* __PERF_MAP_H */
diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index 3ce0498..bacf60b 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -15,7 +15,6 @@ struct thread *thread__new(pid_t pid, pid_t tid)
 	struct thread *thread = zalloc(sizeof(*thread));
 
 	if (thread != NULL) {
-		map_groups__init(&thread->mg);
 		thread->pid_ = pid;
 		thread->tid = tid;
 		thread->ppid = -1;
@@ -45,12 +44,12 @@ void thread__delete(struct thread *thread)
 {
 	struct comm *comm, *tmp;
 
-	map_groups__exit(&thread->mg);
 	list_for_each_entry_safe(comm, tmp, &thread->comm_list, list) {
 		list_del(&comm->list);
 		comm__free(comm);
 	}
 
+	thread__map_groups_put(thread);
 	free(thread);
 }
 
@@ -111,18 +110,85 @@ int thread__comm_len(struct thread *thread)
 size_t thread__fprintf(struct thread *thread, FILE *fp)
 {
 	return fprintf(fp, "Thread %d %s\n", thread->tid, thread__comm_str(thread)) +
-	       map_groups__fprintf(&thread->mg, verbose, fp);
+	       map_groups__fprintf(thread->mg, verbose, fp);
 }
 
-void thread__insert_map(struct thread *thread, struct map *map)
+int thread__insert_map(struct thread *thread, struct map *map)
 {
-	map_groups__fixup_overlappings(&thread->mg, map, verbose, stderr);
-	map_groups__insert(&thread->mg, map);
+	struct map_groups *mg = thread->mg;
+
+	if (!mg) {
+		mg = thread__map_groups_get(thread);
+		if (!mg)
+			return -ENOMEM;
+	}
+
+	map_groups__fixup_overlappings(mg, map, verbose, stderr);
+	map_groups__insert(mg, map);
+	return 0;
+}
+
+static struct map_groups *thread__map_groups_alloc(struct thread *thread)
+{
+	struct map_groups *mg = zalloc(sizeof(*mg));
+
+	if (mg) {
+		map_groups__init(mg);
+		thread->mg = mg;
+	}
+
+	return mg;
+}
+
+struct map_groups *thread__map_groups_get(struct thread *thread)
+{
+	struct map_groups *mg = thread->mg;
+
+	if (!mg)
+		mg = thread__map_groups_alloc(thread);
+
+	return mg;
+}
+
+void thread__map_groups_put(struct thread *thread)
+{
+	if (thread->mg) {
+		map_groups__exit(thread->mg);
+		zfree(&thread->mg);
+	}
+}
+
+static int thread__clone_map_groups(struct thread *thread,
+				    struct thread *parent)
+{
+	struct map_groups *mg;
+	int i;
+
+	/* This is new thread, we share map groups for process. */
+	if (thread->pid_ == parent->pid_)
+		return 0;
+
+	/*
+	 * But this one is new process, copy maps.. if there's
+	 * anything to copy ;-)
+	 */
+	if (!parent->mg)
+		return 0;
+
+	mg = thread__map_groups_alloc(thread);
+	if (!mg)
+		return -ENOMEM;
+
+	for (i = 0; i < MAP__NR_TYPES; ++i)
+		if (map_groups__clone(mg, parent->mg, i) < 0)
+			return -ENOMEM;
+
+	return 0;
 }
 
 int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp)
 {
-	int i, err;
+	int err;
 
 	if (parent->comm_set) {
 		const char *comm = thread__comm_str(parent);
@@ -134,13 +200,9 @@ int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp)
 		thread->comm_set = true;
 	}
 
-	for (i = 0; i < MAP__NR_TYPES; ++i)
-		if (map_groups__clone(&thread->mg, &parent->mg, i) < 0)
-			return -ENOMEM;
-
 	thread->ppid = parent->tid;
 
-	return 0;
+	return thread__clone_map_groups(thread, parent);
 }
 
 void thread__find_cpumode_addr_location(struct thread *thread,
diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h
index 9b29f08..b3f7d8e 100644
--- a/tools/perf/util/thread.h
+++ b/tools/perf/util/thread.h
@@ -13,7 +13,7 @@ struct thread {
 		struct rb_node	 rb_node;
 		struct list_head node;
 	};
-	struct map_groups	mg;
+	struct map_groups	*mg;
 	pid_t			pid_; /* Not all tools update this */
 	pid_t			tid;
 	pid_t			ppid;
@@ -40,7 +40,7 @@ int thread__set_comm(struct thread *thread, const char *comm, u64 timestamp);
 int thread__comm_len(struct thread *thread);
 struct comm *thread__comm(const struct thread *thread);
 const char *thread__comm_str(const struct thread *thread);
-void thread__insert_map(struct thread *thread, struct map *map);
+int thread__insert_map(struct thread *thread, struct map *map);
 int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp);
 size_t thread__fprintf(struct thread *thread, FILE *fp);
 
@@ -77,4 +77,8 @@ static inline bool thread__is_filtered(struct thread *thread)
 	return false;
 }
 
+struct map_groups *thread__map_groups_get(struct thread *thread);
+
+void thread__map_groups_put(struct thread *thread);
+
 #endif	/* __PERF_THREAD_H */
-- 
1.8.3.1

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