perf tools: Release thread resources on PERF_RECORD_EXIT

For long running sessions with many threads with short lifetimes the
amount of memory that the buildid process takes is too much.

Since we don't have hist_entries that may be pointing to them, we can
just release the resources associated with each thread when the exit
(PERF_RECORD_EXIT) event is received.

For normal processing we need to annotate maps with hits, and thus
hist_entries pointing to it and drop the ones that had none. Will be
done in a followup patch.

Cc: David S. Miller <davem@davemloft.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c
index 5c26e2d314af..e437edb72417 100644
--- a/tools/perf/util/build-id.c
+++ b/tools/perf/util/build-id.c
@@ -12,6 +12,7 @@
 #include "event.h"
 #include "symbol.h"
 #include <linux/kernel.h>
+#include "debug.h"
 
 static int build_id__mark_dso_hit(event_t *event, struct perf_session *session)
 {
@@ -34,10 +35,27 @@ static int build_id__mark_dso_hit(event_t *event, struct perf_session *session)
         return 0;
 }
 
+static int event__exit_del_thread(event_t *self, struct perf_session *session)
+{
+        struct thread *thread = perf_session__findnew(session, self->fork.tid);
+
+        dump_printf("(%d:%d):(%d:%d)\n", self->fork.pid, self->fork.tid,
+                    self->fork.ppid, self->fork.ptid);
+
+        if (thread) {
+                rb_erase(&thread->rb_node, &session->threads);
+                session->last_match = NULL;
+                thread__delete(thread);
+        }
+
+        return 0;
+}
+
 struct perf_event_ops build_id__mark_dso_hit_ops = {
         .sample = build_id__mark_dso_hit,
         .mmap   = event__process_mmap,
         .fork   = event__process_task,
+        .exit   = event__exit_del_thread,
 };
 
 char *dso__build_id_filename(struct dso *self, char *bf, size_t size)