perf session: Register the idle thread in perf_session__process_events

No need for all tools to register it and then immediately call
perf_session__process_events.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1260741029-4430-3-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 16 insertions, 0 deletions

diff --git a/tools/perf/util/data_map.c b/tools/perf/util/data_map.c
index ba5bcfa1f908..36e3bfe73196 100644
--- a/tools/perf/util/data_map.c
+++ b/tools/perf/util/data_map.c
@@ -1,6 +1,7 @@
 #include "symbol.h"
 #include "util.h"
 #include "debug.h"
+#include "thread.h"
 #include "session.h"
 
 static unsigned long    mmap_window = 32;
@@ -127,6 +128,18 @@ out:
         return err;
 }
 
+static struct thread *perf_session__register_idle_thread(struct perf_session *self __used)
+{
+        struct thread *thread = threads__findnew(0);
+
+        if (!thread || thread__set_comm(thread, "swapper")) {
+                pr_err("problem inserting idle task.\n");
+                thread = NULL;
+        }
+
+        return thread;
+}
+
 int perf_session__process_events(struct perf_session *self,
                                  struct perf_event_ops *ops,
                                  int full_paths, int *cwdlen, char **cwd)
@@ -140,6 +153,9 @@ int perf_session__process_events(struct perf_session *self,
         uint32_t size;
         char *buf;
 
+        if (perf_session__register_idle_thread(self) == NULL)
+                return -ENOMEM;
+
         perf_event_ops__fill_defaults(ops);
 
         page_size = getpagesize();