perf hist: Correct hist_entry->mem_info refcounts

The 'struct mem_info' is created by iter_prepare_mem_entry() at the
beginning and destroyed by iter_finish_mem_entry() at the end.

So if it's used in a new hist_entry, it should be cloned.

Simplify (hopefully) the logic by adding some helper functions and by
not holding the refcount in the temporary entry.

Signed-off-by: Namhyung Kim <[e-mail]>
Cc: Adrian Hunter <[e-mail]>
Cc: Athira Rajeev <[e-mail]>
Cc: Ian Rogers <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Kan Liang <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Stephane Eranian <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/hist.c

···
 		he->branch_info->to.ms.map = map__get(he->branch_info->to.ms.map);
 	}
 
+	if (he->mem_info) {
+		he->mem_info = mem_info__clone(template->mem_info);
+		if (he->mem_info == NULL)
+			goto err_infos;
+	}
+
 	if (hist_entry__has_callchains(he) && symbol_conf.use_callchain)
 		callchain_init(he->callchain);
 
···
 			if (symbol_conf.cumulate_callchain)
 				he_stat__add_period(he->stat_acc, period);
 
-			/*
-			 * This mem info was allocated from sample__resolve_mem
-			 * and will not be used anymore.
-			 */
-			mem_info__zput(entry->mem_info);
-
 			block_info__delete(entry->block_info);
 
 			kvm_info__zput(entry->kvm_info);
···
 		.filtered = symbol__parent_filter(sym_parent) | al->filtered,
 		.hists	= hists,
 		.branch_info = bi,
-		.mem_info = mem_info__get(mi),
+		.mem_info = mi,
 		.kvm_info = ki,
 		.block_info = block_info,
 		.transaction = sample->transaction,

tools/perf/util/map_symbol.c

···
 {
 	map_symbol__exit(&ams->ms);
 }
+
+void map_symbol__copy(struct map_symbol *dst, struct map_symbol *src)
+{
+	dst->maps = maps__get(src->maps);
+	dst->map = map__get(src->map);
+	dst->sym = src->sym;
+}
+
+void addr_map_symbol__copy(struct addr_map_symbol *dst, struct addr_map_symbol *src)
+{
+	map_symbol__copy(&dst->ms, &src->ms);
+
+	dst->addr = src->addr;
+	dst->al_addr = src->al_addr;
+	dst->al_level = src->al_level;
+	dst->phys_addr = src->phys_addr;
+	dst->data_page_size = src->data_page_size;
+}

tools/perf/util/map_symbol.h

···
 void map_symbol__exit(struct map_symbol *ms);
 void addr_map_symbol__exit(struct addr_map_symbol *ams);
 
+void map_symbol__copy(struct map_symbol *dst, struct map_symbol *src);
+void addr_map_symbol__copy(struct addr_map_symbol *dst, struct addr_map_symbol *src);
+
 #endif // __PERF_MAP_SYMBOL

tools/perf/util/mem-info.c

···
 
 	return result;
 }
+
+struct mem_info *mem_info__clone(struct mem_info *mi)
+{
+	struct mem_info *result = mem_info__new();
+
+	if (result) {
+		addr_map_symbol__copy(mem_info__iaddr(result), mem_info__iaddr(mi));
+		addr_map_symbol__copy(mem_info__daddr(result), mem_info__daddr(mi));
+		mem_info__data_src(result)->val = mem_info__data_src(mi)->val;
+	}
+
+	return result;
+}

tools/perf/util/mem-info.h

···
 };
 
 struct mem_info *mem_info__new(void);
+struct mem_info *mem_info__clone(struct mem_info *mi);
 struct mem_info *mem_info__get(struct mem_info *mi);
 void   mem_info__put(struct mem_info *mi);