On Sat, Oct 08, 2016 at 11:13:21PM -0700, Krister Johansen wrote:
> On Fri, Oct 07, 2016 at 11:22:00AM +0900, Namhyung Kim wrote:
> > On Wed, Oct 05, 2016 at 08:45:24AM -0300, Arnaldo Carvalho de Melo wrote:
> > > Em Sat, Oct 01, 2016 at 08:13:36PM -0700, Krister Johansen escreveu:
> > > > diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
> > > > index b02992e..f8335e8 100644
> > > > --- a/tools/perf/util/hist.c
> > > > +++ b/tools/perf/util/hist.c
> > > > @@ -979,6 +982,7 @@ iter_finish_cumulative_entry(struct hist_entry_iter
> > > > *iter,
> > > > {
> > > > zfree(&iter->priv);
> > > > iter->he = NULL;
> > > > + map__zput(al->map);
> >
> > What is this needed? Why other places like iter_finish_normal_entry
> > isn't?
>
> I put a map__zput() here because iter_next_cumulative_entry() calls
> fill_callchain_info(), which takes a reference on the al->map in the
> struct addr_location that it returns. I had forgotten all of this by
> the time you asked. When I went back to work out my rationale, I
> stumbled across addr_location__put(). Think it would make sense to
> relocate the put of al->map there instead?
I gave the addr_location__put() approach a try, but it caused me to
remember why I had kept this small. There are certain circumstances
where callers that lookup maps don't take references, seemingly because
the map is already contained within a map group. If I move this to
addr_location__put(), then I need to expand the scope of this change.
Right now, it's just focusing on making sure that any map that gets
embedded into a callchain cursor, or retrieved from one and held onto,
gets referenced.
In other words, moving this to addr_location__put() frees a bunch of
maps that are acquired from elsewhere without their reference counts
incremented.
I made the rest of the modifications we discussed. I'll send a v2 patch
in a separate e-mail.
-K
