perf hists: Remove hist_entry->used, not used anymore

Since hist_entry__delete() nowadays doesn't actually frees anything that
may be in use by the annotation code.

Eventually we will solve this for good by reference counting struct
symbol.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-uldtgljymtrkns0knpiso5op@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/ui/browsers/hists.c

@@ -1731,12 +1731,7 @@ do_annotate:
 			if (!notes->src)
 				continue;
 
-			/*
-			 * Don't let this be freed, say, by hists__decay_entry.
-			 */
-			he->used = true;
 			err = hist_entry__tui_annotate(he, evsel, hbt);
-			he->used = false;
 			/*
 			 * offer option to annotate the other branch source or target
 			 * (if they exists) when returning from annotate

tools/perf/util/hist.c

@@ -263,15 +263,9 @@ void hists__decay_entries(struct hists *hists, bool zap_user, bool zap_kernel)
 	while (next) {
 		n = rb_entry(next, struct hist_entry, rb_node);
 		next = rb_next(&n->rb_node);
-		/*
-		 * We may be annotating this, for instance, so keep it here in
-		 * case some it gets new samples, we'll eventually free it when
-		 * the user stops browsing and it agains gets fully decayed.
-		 */
 		if (((zap_user && n->level == '.') ||
 		     (zap_kernel && n->level != '.') ||
-		     hists__decay_entry(hists, n)) &&
-		    !n->used) {
+		     hists__decay_entry(hists, n))) {
 			hists__delete_entry(hists, n);
 		}
 	}

tools/perf/util/sort.h

@@ -102,7 +102,6 @@ struct hist_entry {
 
 	bool			init_have_children;
 	char			level;
-	bool			used;
 	u8			filtered;
 	char			*srcline;
 	struct symbol		*parent;