perf tools: Add refcnt into struct mem_info

It's passed along several hists entries in --hierarchy mode, so it's
better we keep track of it.

The current fail I see is that it gets removed in hierarchy --mem-mode
mode, where it's shared in the different hierarchies, but removed from
the template hist entry, so the report crashes.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180307155020.32613-6-jolsa@kernel.org
[ Rename mem_info__aloc() to mem_info__new(), to fix the typo and use the convention for constructors ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index a1a312d..62b2dd2 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -2221,3 +2221,25 @@ int symbol__config_symfs(const struct option *opt __maybe_unused,
 	free(bf);
 	return 0;
 }
+
+struct mem_info *mem_info__get(struct mem_info *mi)
+{
+	if (mi)
+		refcount_inc(&mi->refcnt);
+	return mi;
+}
+
+void mem_info__put(struct mem_info *mi)
+{
+	if (mi && refcount_dec_and_test(&mi->refcnt))
+		free(mi);
+}
+
+struct mem_info *mem_info__new(void)
+{
+	struct mem_info *mi = zalloc(sizeof(*mi));
+
+	if (mi)
+		refcount_set(&mi->refcnt, 1);
+	return mi;
+}