perf tools: Copy metric events properly when expand cgroups

The metricgroup__copy_metric_events() is to handle metrics events when
expanding event for cgroups.  As the metric events keep pointers to
evsel, it should be refreshed when events are cloned during the
operation.

The perf_stat__collect_metric_expr() is also called in case an event has
a metric directly.

During the copy, it references evsel by index as the evlist now has
cloned evsels for the given cgroup.

Also kernel test robot found an issue in the python module import so add
empty implementations of those two functions to fix it.

Reported-by: kernel test robot <rong.a.chen@intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20200924124455.336326-4-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 85 insertions, 0 deletions

diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c
index 941702cb6a79..55ea514ac0ce 100644
--- a/tools/perf/util/metricgroup.c
+++ b/tools/perf/util/metricgroup.c
@@ -24,6 +24,7 @@
 #include <api/fs/fs.h>
 #include "util.h"
 #include <asm/bug.h>
+#include "cgroup.h"
 
 struct metric_event *metricgroup__lookup(struct rblist *metric_events,
 					 struct evsel *evsel,
@@ -1120,3 +1121,87 @@ bool metricgroup__has_metric(const char *metric)
 	}
 	return false;
 }
+
+int metricgroup__copy_metric_events(struct evlist *evlist, struct cgroup *cgrp,
+				    struct rblist *new_metric_events,
+				    struct rblist *old_metric_events)
+{
+	unsigned i;
+
+	for (i = 0; i < rblist__nr_entries(old_metric_events); i++) {
+		struct rb_node *nd;
+		struct metric_event *old_me, *new_me;
+		struct metric_expr *old_expr, *new_expr;
+		struct evsel *evsel;
+		size_t alloc_size;
+		int idx, nr;
+
+		nd = rblist__entry(old_metric_events, i);
+		old_me = container_of(nd, struct metric_event, nd);
+
+		evsel = evlist__find_evsel(evlist, old_me->evsel->idx);
+		if (!evsel)
+			return -EINVAL;
+		new_me = metricgroup__lookup(new_metric_events, evsel, true);
+		if (!new_me)
+			return -ENOMEM;
+
+		pr_debug("copying metric event for cgroup '%s': %s (idx=%d)\n",
+			 cgrp ? cgrp->name : "root", evsel->name, evsel->idx);
+
+		list_for_each_entry(old_expr, &old_me->head, nd) {
+			new_expr = malloc(sizeof(*new_expr));
+			if (!new_expr)
+				return -ENOMEM;
+
+			new_expr->metric_expr = old_expr->metric_expr;
+			new_expr->metric_name = old_expr->metric_name;
+			new_expr->metric_unit = old_expr->metric_unit;
+			new_expr->runtime = old_expr->runtime;
+
+			if (old_expr->metric_refs) {
+				/* calculate number of metric_events */
+				for (nr = 0; old_expr->metric_refs[nr].metric_name; nr++)
+					continue;
+				alloc_size = sizeof(*new_expr->metric_refs);
+				new_expr->metric_refs = calloc(nr + 1, alloc_size);
+				if (!new_expr->metric_refs) {
+					free(new_expr);
+					return -ENOMEM;
+				}
+
+				memcpy(new_expr->metric_refs, old_expr->metric_refs,
+				       nr * alloc_size);
+			} else {
+				new_expr->metric_refs = NULL;
+			}
+
+			/* calculate number of metric_events */
+			for (nr = 0; old_expr->metric_events[nr]; nr++)
+				continue;
+			alloc_size = sizeof(*new_expr->metric_events);
+			new_expr->metric_events = calloc(nr + 1, alloc_size);
+			if (!new_expr->metric_events) {
+				free(new_expr->metric_refs);
+				free(new_expr);
+				return -ENOMEM;
+			}
+
+			/* copy evsel in the same position */
+			for (idx = 0; idx < nr; idx++) {
+				evsel = old_expr->metric_events[idx];
+				evsel = evlist__find_evsel(evlist, evsel->idx);
+				if (evsel == NULL) {
+					free(new_expr->metric_events);
+					free(new_expr->metric_refs);
+					free(new_expr);
+					return -EINVAL;
+				}
+				new_expr->metric_events[idx] = evsel;
+			}
+
+			list_add(&new_expr->nd, &new_me->head);
+		}
+	}
+	return 0;
+}