perf metric: Collect referenced metrics in struct metric_ref_node

Collecting referenced metrics in struct metric_ref_node object,
so we can process them later on.

The change will parse nested metric names out of expression and
'resolve' them.

All referenced metrics are dissolved into one context, meaning all
nested metrics events and added to the parent context.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Clarke <pc@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20200719181320.785305-9-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Author: olsajiri

tools/perf/util/metricgroup.c

@@ -102,12 +102,25 @@ void metricgroup__rblist_exit(struct rblist *metric_events)
 	rblist__exit(metric_events);
 }
 
+/*
+ * A node in the list of referenced metrics. metric_expr
+ * is held as a convenience to avoid a search through the
+ * metric list.
+ */
+struct metric_ref_node {
+	const char *metric_name;
+	const char *metric_expr;
+	struct list_head list;
+};
+
 struct egroup {
 	struct list_head nd;
 	struct expr_parse_ctx pctx;
 	const char *metric_name;
 	const char *metric_expr;
 	const char *metric_unit;
+	struct list_head metric_refs;
+	int metric_refs_cnt;
 	int runtime;
 	bool has_constraint;
 };
@@ -574,27 +587,72 @@ int __weak arch_get_runtimeparam(void)
 static int __add_metric(struct list_head *group_list,
 			struct pmu_event *pe,
 			bool metric_no_group,
-			int runtime)
+			int runtime,
+			struct egroup **egp)
 {
+	struct metric_ref_node *ref;
 	struct egroup *eg;
 
-	eg = malloc(sizeof(*eg));
-	if (!eg)
-		return -ENOMEM;
+	if (*egp == NULL) {
+		/*
+		 * We got in here for the parent group,
+		 * allocate it and put it on the list.
+		 */
+		eg = malloc(sizeof(*eg));
+		if (!eg)
+			return -ENOMEM;
+
+		expr__ctx_init(&eg->pctx);
+		eg->metric_name = pe->metric_name;
+		eg->metric_expr = pe->metric_expr;
+		eg->metric_unit = pe->unit;
+		eg->runtime = runtime;
+		eg->has_constraint = metric_no_group || metricgroup__has_constraint(pe);
+		INIT_LIST_HEAD(&eg->metric_refs);
+		eg->metric_refs_cnt = 0;
+		*egp = eg;
+	} else {
+		/*
+		 * We got here for the referenced metric, via the
+		 * recursive metricgroup__add_metric call, add
+		 * it to the parent group.
+		 */
+		eg = *egp;
+
+		ref = malloc(sizeof(*ref));
+		if (!ref)
+			return -ENOMEM;
 
-	expr__ctx_init(&eg->pctx);
-	eg->metric_name = pe->metric_name;
-	eg->metric_expr = pe->metric_expr;
-	eg->metric_unit = pe->unit;
-	eg->runtime = runtime;
-	eg->has_constraint = metric_no_group || metricgroup__has_constraint(pe);
+		/*
+		 * Intentionally passing just const char pointers,
+		 * from 'pe' object, so they never go away. We don't
+		 * need to change them, so there's no need to create
+		 * our own copy.
+		 */
+		ref->metric_name = pe->metric_name;
+		ref->metric_expr = pe->metric_expr;
+
+		list_add(&ref->list, &eg->metric_refs);
+		eg->metric_refs_cnt++;
+	}
 
+	/*
+	 * For both the parent and referenced metrics, we parse
+	 * all the metric's IDs and add it to the parent context.
+	 */
 	if (expr__find_other(pe->metric_expr, NULL, &eg->pctx, runtime) < 0) {
 		expr__ctx_clear(&eg->pctx);
 		free(eg);
 		return -EINVAL;
 	}
 
+	/*
+	 * We add new group only in the 'parent' call,
+	 * so bail out for referenced metric case.
+	 */
+	if (eg->metric_refs_cnt)
+		return 0;
+
 	if (list_empty(group_list))
 		list_add(&eg->nd, group_list);
 	else {
@@ -625,16 +683,94 @@ static int __add_metric(struct list_head *group_list,
 		    (match_metric(__pe->metric_group, __metric) ||	\
 		     match_metric(__pe->metric_name, __metric)))
 
+static struct pmu_event *find_metric(const char *metric, struct pmu_events_map *map)
+{
+	struct pmu_event *pe;
+	int i;
+
+	map_for_each_event(pe, i, map) {
+		if (match_metric(pe->metric_name, metric))
+			return pe;
+	}
+
+	return NULL;
+}
+
 static int add_metric(struct list_head *group_list,
 		      struct pmu_event *pe,
-		      bool metric_no_group)
+		      bool metric_no_group,
+		      struct egroup **egp);
+
+static int __resolve_metric(struct egroup *eg,
+			    bool metric_no_group,
+			    struct list_head *group_list,
+			    struct pmu_events_map *map)
 {
+	struct hashmap_entry *cur;
+	size_t bkt;
+	bool all;
+	int ret;
+
+	/*
+	 * Iterate all the parsed IDs and if there's metric,
+	 * add it to the context.
+	 */
+	do {
+		all = true;
+		hashmap__for_each_entry((&eg->pctx.ids), cur, bkt) {
+			struct pmu_event *pe;
+
+			pe = find_metric(cur->key, map);
+			if (!pe)
+				continue;
+
+			all = false;
+			/* The metric key itself needs to go out.. */
+			expr__del_id(&eg->pctx, cur->key);
+
+			/* ... and it gets resolved to the parent context. */
+			ret = add_metric(group_list, pe, metric_no_group, &eg);
+			if (ret)
+				return ret;
+
+			/*
+			 * We added new metric to hashmap, so we need
+			 * to break the iteration and start over.
+			 */
+			break;
+		}
+	} while (!all);
+
+	return 0;
+}
+
+static int resolve_metric(bool metric_no_group,
+			  struct list_head *metric_list,
+			  struct pmu_events_map *map)
+{
+	struct egroup *eg;
+	int err;
+
+	list_for_each_entry(eg, metric_list, nd) {
+		err = __resolve_metric(eg, metric_no_group, metric_list, map);
+		if (err)
+			return err;
+	}
+	return 0;
+}
+
+static int add_metric(struct list_head *group_list,
+		      struct pmu_event *pe,
+		      bool metric_no_group,
+		      struct egroup **egp)
+{
+	struct egroup *orig = *egp;
 	int ret = 0;
 
 	pr_debug("metric expr %s for %s\n", pe->metric_expr, pe->metric_name);
 
 	if (!strstr(pe->metric_expr, "?")) {
-		ret = __add_metric(group_list, pe, metric_no_group, 1);
+		ret = __add_metric(group_list, pe, metric_no_group, 1, egp);
 	} else {
 		int j, count;
 
@@ -645,9 +781,8 @@ static int add_metric(struct list_head *group_list,
 		 * those events to group_list.
 		 */
 
-		for (j = 0; j < count && !ret; j++) {
-			ret = __add_metric(group_list, pe, metric_no_group, j);
-		}
+		for (j = 0; j < count && !ret; j++, *egp = orig)
+			ret = __add_metric(group_list, pe, metric_no_group, j, egp);
 	}
 
 	return ret;
@@ -665,8 +800,18 @@ static int metricgroup__add_metric(const char *metric, bool metric_no_group,
 
 	map_for_each_metric(pe, i, map, metric) {
 		has_match = true;
+		eg = NULL;
+
+		ret = add_metric(group_list, pe, metric_no_group, &eg);
+		if (ret)
+			return ret;
 
-		ret = add_metric(group_list, pe, metric_no_group);
+		/*
+		 * Process any possible referenced metrics
+		 * included in the expression.
+		 */
+		ret = resolve_metric(metric_no_group,
+				     group_list, map);
 		if (ret)
 			return ret;
 	}
@@ -723,11 +868,22 @@ static int metricgroup__add_metric_list(const char *list, bool metric_no_group,
 	return ret;
 }
 
+static void egroup__free_refs(struct egroup *egroup)
+{
+	struct metric_ref_node *ref, *tmp;
+
+	list_for_each_entry_safe(ref, tmp, &egroup->metric_refs, list) {
+		list_del(&ref->list);
+		free(ref);
+	}
+}
+
 static void metricgroup__free_egroups(struct list_head *group_list)
 {
 	struct egroup *eg, *egtmp;
 
 	list_for_each_entry_safe (eg, egtmp, group_list, nd) {
+		egroup__free_refs(eg);
 		expr__ctx_clear(&eg->pctx);
 		list_del_init(&eg->nd);
 		free(eg);