perf tools: Limit ordered events queue size

Add limit to the ordered events queue allocation. This way we will be
able to control the size of the queue buffers.

There's no limit at the moment (it's set to (u64) -1). The config code
will come in following patches.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: David Ahern <dsahern@gmail.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jean Pihet <jean.pihet@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-lw1ny3mk4ctb6su5ght5rsng@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/session.c

@@ -78,6 +78,8 @@ struct perf_session *perf_session__new(struct perf_data_file *file,
 	INIT_LIST_HEAD(&session->ordered_events.events);
 	INIT_LIST_HEAD(&session->ordered_events.cache);
 	INIT_LIST_HEAD(&session->ordered_events.to_free);
+	session->ordered_events.max_alloc_size = (u64) -1;
+	session->ordered_events.cur_alloc_size = 0;
 	machines__init(&session->machines);
 
 	if (file) {
@@ -518,7 +520,7 @@ static void queue_event(struct ordered_events *oe, struct ordered_event *new)
 static struct ordered_event *alloc_event(struct ordered_events *oe)
 {
 	struct list_head *cache = &oe->cache;
-	struct ordered_event *new;
+	struct ordered_event *new = NULL;
 
 	if (!list_empty(cache)) {
 		new = list_entry(cache->next, struct ordered_event, list);
@@ -527,10 +529,14 @@ static struct ordered_event *alloc_event(struct ordered_events *oe)
 		new = oe->buffer + oe->buffer_idx;
 		if (++oe->buffer_idx == MAX_SAMPLE_BUFFER)
 			oe->buffer = NULL;
-	} else {
-		oe->buffer = malloc(MAX_SAMPLE_BUFFER * sizeof(*new));
+	} else if (oe->cur_alloc_size < oe->max_alloc_size) {
+		size_t size = MAX_SAMPLE_BUFFER * sizeof(*new);
+
+		oe->buffer = malloc(size);
 		if (!oe->buffer)
 			return NULL;
+
+		oe->cur_alloc_size += size;
 		list_add(&oe->buffer->list, &oe->to_free);
 
 		/* First entry is abused to maintain the to_free list. */

tools/perf/util/session.h

@@ -20,6 +20,8 @@ struct ordered_events {
 	u64			last_flush;
 	u64			next_flush;
 	u64			max_timestamp;
+	u64			max_alloc_size;
+	u64			cur_alloc_size;
 	struct list_head	events;
 	struct list_head	cache;
 	struct list_head	to_free;