Re: [PATCH 3/5] perf tools: Reference count map_groups objects

[Jiri Olsa <jolsa@redhat.com>]

On Mon, Apr 14, 2014 at 11:22:02AM -0600, David Ahern wrote:
> On 4/14/14, 9:52 AM, Jiri Olsa wrote:

SNIP

> >
> >+void map_groups__put(struct map_groups *mg)
> >+{
> >+	if (--mg->refcnt == 0)
> >+		map_groups__delete(mg);
> >+}
> >+
> >  void map_groups__flush(struct map_groups *mg)
> >  {
> >  	int type;
> >diff --git a/tools/perf/util/map.h b/tools/perf/util/map.h
> >index 1073e2d..d6445b2 100644
> >--- a/tools/perf/util/map.h
> >+++ b/tools/perf/util/map.h
> >@@ -59,11 +59,20 @@ struct map_groups {
> >  	struct rb_root	 maps[MAP__NR_TYPES];
> >  	struct list_head removed_maps[MAP__NR_TYPES];
> >  	struct machine	 *machine;
> >+	int		 refcnt;
> >  };
> 
> 
> atomic for refcnt? This is part of a libperf; would be good to
> support multithreaded users.

hum.. I think using atomic type is not enough, we'd need
to make map_groups__put/get atomic as well

not sure what's the support in user space for that.. will check

also not to be negative, but libperf is not thread safe anyway, right? ;-)

thanks,
jirka