Re: [PATCH 06/21] perf hists: Return error from hists__collapse_resort()

[Arnaldo Carvalho de Melo]

Em Tue, Feb 02, 2016 at 01:52:05PM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Tue, Feb 02, 2016 at 11:39:48PM +0900, Namhyung Kim escreveu:
> > Currently hists__collapse_resort() and hists__collapse_insert_entry()
> > don't return error code. Now callchain_merge() can check error case,
> > abort and pass the error to the user.  Later patch can add more work
> > which can be failed too.
> > 
> > Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> > Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
> > ---
> >  tools/perf/util/hist.c | 27 +++++++++++++++++----------
> >  tools/perf/util/hist.h |  4 ++--
> >  2 files changed, 19 insertions(+), 12 deletions(-)
> > 
> > diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
> > index 098310bc4489..b476b599e415 100644
> > --- a/tools/perf/util/hist.c
> > +++ b/tools/perf/util/hist.c
> > @@ -1016,8 +1016,8 @@ void hist_entry__delete(struct hist_entry *he)
> >   * collapse the histogram
> >   */
> >  
> > -bool hists__collapse_insert_entry(struct hists *hists __maybe_unused,
> > -				  struct rb_root *root, struct hist_entry *he)
> > +int hists__collapse_insert_entry(struct hists *hists, struct rb_root *root,
> > +				 struct hist_entry *he)
> >  {
> >  	struct rb_node **p = &root->rb_node;
> >  	struct rb_node *parent = NULL;
> > @@ -1037,12 +1037,13 @@ bool hists__collapse_insert_entry(struct hists *hists __maybe_unused,
> >  
> >  			if (symbol_conf.use_callchain) {
> >  				callchain_cursor_reset(&callchain_cursor);
> > -				callchain_merge(&callchain_cursor,
> > -						iter->callchain,
> > -						he->callchain);
> > +				if (callchain_merge(&callchain_cursor,
> > +						    iter->callchain,
> > +						    he->callchain) < 0)
> > +					return -1;
> 
> So now we're exiting on error here, whereas before we would
> unconditionally call hist_entry__delete() right after this branch... Is
> that right?

> >  			}
> >  			hist_entry__delete(he);
> > -			return false;
> > +			return 0;
> >  		}
> 

> Looking at it...

Below it does:

 		rb_erase(&n->rb_node_in, root);
-		if (hists__collapse_insert_entry(hists, &hists->entries_collapsed, n)) {
+		ret = hists__collapse_insert_entry(hists, &hists->entries_collapsed, n);
+		if (ret < 0)
+			return -1;

So, we remove it from the rb tree it is in, and previously we expected
that hists__collapse_insert_entry would hist_entry__delete(n), while
now, if callchain_merge() fails, we leak it, no?

- Arnaldo

> >  
> >  		if (cmp < 0)
> > @@ -1054,7 +1055,7 @@ bool hists__collapse_insert_entry(struct hists *hists __maybe_unused,
> >  
> >  	rb_link_node(&he->rb_node_in, parent, p);
> >  	rb_insert_color(&he->rb_node_in, root);
> > -	return true;
> > +	return 1;
> >  }
> >  
> >  struct rb_root *hists__get_rotate_entries_in(struct hists *hists)
> > @@ -1080,14 +1081,15 @@ static void hists__apply_filters(struct hists *hists, struct hist_entry *he)
> >  	hists__filter_entry_by_socket(hists, he);
> >  }
> >  
> > -void hists__collapse_resort(struct hists *hists, struct ui_progress *prog)
> > +int hists__collapse_resort(struct hists *hists, struct ui_progress *prog)
> >  {
> >  	struct rb_root *root;
> >  	struct rb_node *next;
> >  	struct hist_entry *n;
> > +	int ret;
> >  
> >  	if (!sort__need_collapse)
> > -		return;
> > +		return 0;
> >  
> >  	hists->nr_entries = 0;
> >  
> > @@ -1102,7 +1104,11 @@ void hists__collapse_resort(struct hists *hists, struct ui_progress *prog)
> >  		next = rb_next(&n->rb_node_in);
> >  
> >  		rb_erase(&n->rb_node_in, root);
> > -		if (hists__collapse_insert_entry(hists, &hists->entries_collapsed, n)) {
> > +		ret = hists__collapse_insert_entry(hists, &hists->entries_collapsed, n);
> > +		if (ret < 0)
> > +			return -1;
> > +
> > +		if (ret) {
> >  			/*
> >  			 * If it wasn't combined with one of the entries already
> >  			 * collapsed, we need to apply the filters that may have
> > @@ -1113,6 +1119,7 @@ void hists__collapse_resort(struct hists *hists, struct ui_progress *prog)
> >  		if (prog)
> >  			ui_progress__update(prog, 1);
> >  	}
> > +	return 0;
> >  }
> >  
> >  static int hist_entry__sort(struct hist_entry *a, struct hist_entry *b)
> > diff --git a/tools/perf/util/hist.h b/tools/perf/util/hist.h
> > index d4ec4822a103..9c72f8331d1c 100644
> > --- a/tools/perf/util/hist.h
> > +++ b/tools/perf/util/hist.h
> > @@ -129,7 +129,7 @@ int hist_entry__sort_snprintf(struct hist_entry *he, char *bf, size_t size,
> >  void hist_entry__delete(struct hist_entry *he);
> >  
> >  void hists__output_resort(struct hists *hists, struct ui_progress *prog);
> > -void hists__collapse_resort(struct hists *hists, struct ui_progress *prog);
> > +int hists__collapse_resort(struct hists *hists, struct ui_progress *prog);
> >  
> >  void hists__decay_entries(struct hists *hists, bool zap_user, bool zap_kernel);
> >  void hists__delete_entries(struct hists *hists);
> > @@ -188,7 +188,7 @@ int hists__init(void);
> >  int __hists__init(struct hists *hists);
> >  
> >  struct rb_root *hists__get_rotate_entries_in(struct hists *hists);
> > -bool hists__collapse_insert_entry(struct hists *hists __maybe_unused,
> > +int hists__collapse_insert_entry(struct hists *hists,
> >  				  struct rb_root *root, struct hist_entry *he);
> >  
> >  struct perf_hpp {
> > -- 
> > 2.6.4