linux-kernel - [PATCH 5/5] perf tools: Share process map groups within process threads

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Message-Id: <1394805606-25883-6-git-send-email-jolsa@redhat.com>
Date:	Fri, 14 Mar 2014 15:00:06 +0100
From:	Jiri Olsa <jolsa@...hat.com>
To:	linux-kernel@...r.kernel.org
Cc:	Jiri Olsa <jolsa@...hat.com>, Don Zickus <dzickus@...hat.com>,
	Corey Ashford <cjashfor@...ux.vnet.ibm.com>,
	David Ahern <dsahern@...il.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Ingo Molnar <mingo@...nel.org>,
	Namhyung Kim <namhyung@...nel.org>,
	Paul Mackerras <paulus@...ba.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Arnaldo Carvalho de Melo <acme@...stprotocols.net>
Subject: [PATCH 5/5] perf tools: Share process map groups within process threads

Sharing map groups within all process threads. This way
there's only one copy of mmap info and it's reachale
from any thread within the process.

Signed-off-by: Jiri Olsa <jolsa@...hat.com>
Cc: Don Zickus <dzickus@...hat.com>
Cc: Corey Ashford <cjashfor@...ux.vnet.ibm.com>
Cc: David Ahern <dsahern@...il.com>
Cc: Frederic Weisbecker <fweisbec@...il.com>
Cc: Ingo Molnar <mingo@...nel.org>
Cc: Namhyung Kim <namhyung@...nel.org>
Cc: Paul Mackerras <paulus@...ba.org>
Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: Arnaldo Carvalho de Melo <acme@...stprotocols.net>
---
 tools/perf/util/map.h    |  2 ++
 tools/perf/util/thread.c | 37 ++++++++++++++++++++++++++++++++++---
 2 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/map.h b/tools/perf/util/map.h
index 99a6488..d4c8df2 100644
--- a/tools/perf/util/map.h
+++ b/tools/perf/util/map.h
@@ -59,6 +59,8 @@ struct map_groups {
 	struct rb_root	 maps[MAP__NR_TYPES];
 	struct list_head removed_maps[MAP__NR_TYPES];
 	struct machine	 *machine;
+	/* Used for thread sharing */
+	int		  refcnt;
 };
 
 static inline struct kmap *map__kmap(struct map *map)
diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index 7c1aad0..2599754 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -156,6 +156,16 @@ int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp)
 	return 0;
 }
 
+static struct thread* thread__get_leader(struct thread *thread)
+{
+	pid_t pid = thread->pid_;
+
+	if (pid == thread->tid)
+		return thread;
+
+	return machine__findnew_thread(thread->machine, pid, pid);
+}
+
 static struct map_groups* thread__map_groups_alloc(struct thread *thread)
 {
 	struct map_groups* mg = zalloc(sizeof(*mg));
@@ -172,13 +182,34 @@ struct map_groups* thread__map_groups_get(struct thread *thread)
 {
 	struct map_groups* mg = thread->mg;
 
-	if (!mg)
-		mg = thread__map_groups_alloc(thread);
+	if (!mg) {
+		struct thread *leader = thread__get_leader(thread);
+
+		if (!leader)
+			return NULL;
+
+		if (leader->mg)
+			mg = leader->mg;
+		else
+			mg = thread__map_groups_alloc(leader);
+
+		if (leader != thread)
+			thread->mg = mg;
+
+		mg->refcnt++;
+	}
 
 	return mg;
 }
 
 void thread__map_groups_put(struct thread *thread)
 {
-	zfree(&thread->mg);
+	struct map_groups* mg = thread->mg;
+
+	if (mg) {
+		BUG_ON(!mg->refcnt);
+
+		if (!--mg->refcnt)
+			zfree(&thread->mg);
+	}
 }
-- 
1.8.3.1

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