diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index e0a374d..b13f426 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -965,14 +965,14 @@
 	}
 }
 
-static int event__process(event_t *event)
+static int event__process(event_t *event, struct perf_session *session)
 {
 	switch (event->header.type) {
 	case PERF_RECORD_COMM:
-		event__process_comm(event);
+		event__process_comm(event, session);
 		break;
 	case PERF_RECORD_MMAP:
-		event__process_mmap(event);
+		event__process_mmap(event, session);
 		break;
 	default:
 		break;
@@ -999,7 +999,8 @@
 	return head;
 }
 
-static void mmap_read_counter(struct mmap_data *md)
+static void perf_session__mmap_read_counter(struct perf_session *self,
+					    struct mmap_data *md)
 {
 	unsigned int head = mmap_read_head(md);
 	unsigned int old = md->prev;
@@ -1054,7 +1055,7 @@
 		if (event->header.type == PERF_RECORD_SAMPLE)
 			event__process_sample(event, md->counter);
 		else
-			event__process(event);
+			event__process(event, self);
 		old += size;
 	}
 
@@ -1064,13 +1065,13 @@
 static struct pollfd event_array[MAX_NR_CPUS * MAX_COUNTERS];
 static struct mmap_data mmap_array[MAX_NR_CPUS][MAX_COUNTERS];
 
-static void mmap_read(void)
+static void perf_session__mmap_read(struct perf_session *self)
 {
 	int i, counter;
 
 	for (i = 0; i < nr_cpus; i++) {
 		for (counter = 0; counter < nr_counters; counter++)
-			mmap_read_counter(&mmap_array[i][counter]);
+			perf_session__mmap_read_counter(self, &mmap_array[i][counter]);
 	}
 }
 
@@ -1155,11 +1156,16 @@
 	pthread_t thread;
 	int i, counter;
 	int ret;
+	/*
+	 * XXX perf_session__new should allow passing a O_MMAP, so that all this
+	 * mmap reading, etc is encapsulated in it.
+	 */
+	struct perf_session *session = NULL;
 
 	if (target_pid != -1)
-		event__synthesize_thread(target_pid, event__process);
+		event__synthesize_thread(target_pid, event__process, session);
 	else
-		event__synthesize_threads(event__process);
+		event__synthesize_threads(event__process, session);
 
 	for (i = 0; i < nr_cpus; i++) {
 		group_fd = -1;
@@ -1170,7 +1176,7 @@
 	/* Wait for a minimal set of events before starting the snapshot */
 	poll(event_array, nr_poll, 100);
 
-	mmap_read();
+	perf_session__mmap_read(session);
 
 	if (pthread_create(&thread, NULL, display_thread, NULL)) {
 		printf("Could not create display thread.\n");
@@ -1190,7 +1196,7 @@
 	while (1) {
 		int hits = samples;
 
-		mmap_read();
+		perf_session__mmap_read(session);
 
 		if (hits == samples)
 			ret = poll(event_array, nr_poll, 100);