perf hists: Introduce output_resort_cb method

When dealing with nested hist entries it's helpful to have a way to
resort those nested objects.

Adding optional callback call into output_resort function and following
new interface function:

typedef int (*hists__resort_cb_t)(struct hist_entry *he);

void hists__output_resort_cb(struct hists *hists,
struct ui_progress *prog,
hists__resort_cb_t cb);

Signed-off-by: Jiri Olsa <[e-mail]>
Cc: David Ahern <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/hist.c

···
 }
 
 static void output_resort(struct hists *hists, struct ui_progress *prog,
-			  bool use_callchain)
+			  bool use_callchain, hists__resort_cb_t cb)
 {
 	struct rb_root *root;
 	struct rb_node *next;
···
 		n = rb_entry(next, struct hist_entry, rb_node_in);
 		next = rb_next(&n->rb_node_in);
 
+		if (cb && cb(n))
+			continue;
+
 		__hists__insert_output_entry(&hists->entries, n, min_callchain_hits, use_callchain);
 		hists__inc_stats(hists, n);
 
···
 	else
 		use_callchain = symbol_conf.use_callchain;
 
-	output_resort(evsel__hists(evsel), prog, use_callchain);
+	output_resort(evsel__hists(evsel), prog, use_callchain, NULL);
 }
 
 void hists__output_resort(struct hists *hists, struct ui_progress *prog)
 {
-	output_resort(hists, prog, symbol_conf.use_callchain);
+	output_resort(hists, prog, symbol_conf.use_callchain, NULL);
+}
+
+void hists__output_resort_cb(struct hists *hists, struct ui_progress *prog,
+			     hists__resort_cb_t cb)
+{
+	output_resort(hists, prog, symbol_conf.use_callchain, cb);
 }
 
 static bool can_goto_child(struct hist_entry *he, enum hierarchy_move_dir hmd)

tools/perf/util/hist.h

···
 				   struct perf_hpp_fmt *fmt, int printed);
 void hist_entry__delete(struct hist_entry *he);
 
+typedef int (*hists__resort_cb_t)(struct hist_entry *he);
+
 void perf_evsel__output_resort(struct perf_evsel *evsel, struct ui_progress *prog);
 void hists__output_resort(struct hists *hists, struct ui_progress *prog);
+void hists__output_resort_cb(struct hists *hists, struct ui_progress *prog,
+			     hists__resort_cb_t cb);
 int hists__collapse_resort(struct hists *hists, struct ui_progress *prog);
 
 void hists__decay_entries(struct hists *hists, bool zap_user, bool zap_kernel);