perf evlist: Add reference count

This a no-op for most of the perf tool. The reference count is set to
1 at allocation, the put will see the 1, decrement it and perform the
delete.

The purpose for adding the reference count is for the python code. Prior
to this change the python code would clone evlists, but this has issues
if events are opened, etc.

This change adds a reference count for the evlists and a later change
will add it to evsels. The combination is needed for the python code to
operate correctly (not hit asserts in the evsel clone), but the changes
are broken apart for the sake of smaller patches.

Assisted-by: Gemini:gemini-3.1-pro-preview
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alice Rogers <alice.mei.rogers@gmail.com>
Cc: Dapeng Mi <dapeng1.mi@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Leo Yan <leo.yan@linux.dev>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

1 files changed, 110 insertions, 132 deletions

diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
index 98a8dd9b673d..7483741c024a 100644
--- a/tools/perf/util/python.c
+++ b/tools/perf/util/python.c
@@ -1292,7 +1292,7 @@ static int pyrf_evsel__setup_types(void)
 struct pyrf_evlist {
 	PyObject_HEAD
 
-	struct evlist evlist;
+	struct evlist *evlist;
 };
 
 static int pyrf_evlist__init(struct pyrf_evlist *pevlist,
@@ -1302,18 +1302,27 @@ static int pyrf_evlist__init(struct pyrf_evlist *pevlist,
 	struct perf_cpu_map *cpus;
 	struct perf_thread_map *threads;
 
-	if (!PyArg_ParseTuple(args, "OO", &pcpus, &pthreads))
+	if (!PyArg_ParseTuple(args, "O!O!",
+			      &pyrf_cpu_map__type, &pcpus,
+			      &pyrf_thread_map__type, &pthreads))
 		return -1;
 
+	evlist__put(pevlist->evlist);
+	pevlist->evlist = evlist__new();
+	if (!pevlist->evlist) {
+		PyErr_NoMemory();
+		return -1;
+	}
 	threads = ((struct pyrf_thread_map *)pthreads)->threads;
 	cpus = ((struct pyrf_cpu_map *)pcpus)->cpus;
-	evlist__init(&pevlist->evlist, cpus, threads);
+	perf_evlist__set_maps(&pevlist->evlist->core, cpus, threads);
+
 	return 0;
 }
 
 static void pyrf_evlist__delete(struct pyrf_evlist *pevlist)
 {
-	evlist__exit(&pevlist->evlist);
+	evlist__put(pevlist->evlist);
 	Py_TYPE(pevlist)->tp_free((PyObject*)pevlist);
 }
 
@@ -1322,7 +1331,7 @@ static PyObject *pyrf_evlist__all_cpus(struct pyrf_evlist *pevlist)
 	struct pyrf_cpu_map *pcpu_map = PyObject_New(struct pyrf_cpu_map, &pyrf_cpu_map__type);
 
 	if (pcpu_map)
-		pcpu_map->cpus = perf_cpu_map__get(pevlist->evlist.core.all_cpus);
+		pcpu_map->cpus = perf_cpu_map__get(pevlist->evlist->core.all_cpus);
 
 	return (PyObject *)pcpu_map;
 }
@@ -1335,7 +1344,7 @@ static PyObject *pyrf_evlist__metrics(struct pyrf_evlist *pevlist)
 	if (!list)
 		return NULL;
 
-	for (node = rb_first_cached(&pevlist->evlist.metric_events.entries); node;
+	for (node = rb_first_cached(&pevlist->evlist->metric_events.entries); node;
 	     node = rb_next(node)) {
 		struct metric_event *me = container_of(node, struct metric_event, nd);
 		struct list_head *pos;
@@ -1441,7 +1450,7 @@ static PyObject *pyrf_evlist__compute_metric(struct pyrf_evlist *pevlist,
 	if (!PyArg_ParseTuple(args, "sii", &metric, &cpu, &thread))
 		return NULL;
 
-	for (node = rb_first_cached(&pevlist->evlist.metric_events.entries);
+	for (node = rb_first_cached(&pevlist->evlist->metric_events.entries);
 	     mexp == NULL && node;
 	     node = rb_next(node)) {
 		struct metric_event *me = container_of(node, struct metric_event, nd);
@@ -1457,7 +1466,7 @@ static PyObject *pyrf_evlist__compute_metric(struct pyrf_evlist *pevlist,
 			if (e->metric_events[0] == NULL)
 				continue;
 
-			evlist__for_each_entry(&pevlist->evlist, pos2) {
+			evlist__for_each_entry(pevlist->evlist, pos2) {
 				if (pos2->metric_leader != e->metric_events[0])
 					continue;
 				cpu_idx = perf_cpu_map__idx(pos2->core.cpus,
@@ -1502,7 +1511,7 @@ done:
 static PyObject *pyrf_evlist__mmap(struct pyrf_evlist *pevlist,
 				   PyObject *args, PyObject *kwargs)
 {
-	struct evlist *evlist = &pevlist->evlist;
+	struct evlist *evlist = pevlist->evlist;
 	static char *kwlist[] = { "pages", "overwrite", NULL };
 	int pages = 128, overwrite = false;
 
@@ -1522,7 +1531,7 @@ static PyObject *pyrf_evlist__mmap(struct pyrf_evlist *pevlist,
 static PyObject *pyrf_evlist__poll(struct pyrf_evlist *pevlist,
 				   PyObject *args, PyObject *kwargs)
 {
-	struct evlist *evlist = &pevlist->evlist;
+	struct evlist *evlist = pevlist->evlist;
 	static char *kwlist[] = { "timeout", NULL };
 	int timeout = -1, n;
 
@@ -1542,7 +1551,7 @@ static PyObject *pyrf_evlist__get_pollfd(struct pyrf_evlist *pevlist,
 					 PyObject *args __maybe_unused,
 					 PyObject *kwargs __maybe_unused)
 {
-	struct evlist *evlist = &pevlist->evlist;
+	struct evlist *evlist = pevlist->evlist;
         PyObject *list = PyList_New(0);
 	int i;
 
@@ -1571,7 +1580,7 @@ static PyObject *pyrf_evlist__add(struct pyrf_evlist *pevlist,
 				  PyObject *args,
 				  PyObject *kwargs __maybe_unused)
 {
-	struct evlist *evlist = &pevlist->evlist;
+	struct evlist *evlist = pevlist->evlist;
 	PyObject *pevsel;
 	struct evsel *evsel;
 
@@ -1603,7 +1612,7 @@ static struct mmap *get_md(struct evlist *evlist, int cpu)
 static PyObject *pyrf_evlist__read_on_cpu(struct pyrf_evlist *pevlist,
 					  PyObject *args, PyObject *kwargs)
 {
-	struct evlist *evlist = &pevlist->evlist;
+	struct evlist *evlist = pevlist->evlist;
 	union perf_event *event;
 	int sample_id_all = 1, cpu;
 	static char *kwlist[] = { "cpu", "sample_id_all", NULL };
@@ -1660,7 +1669,7 @@ end:
 static PyObject *pyrf_evlist__open(struct pyrf_evlist *pevlist,
 				   PyObject *args, PyObject *kwargs)
 {
-	struct evlist *evlist = &pevlist->evlist;
+	struct evlist *evlist = pevlist->evlist;
 
 	if (evlist__open(evlist) < 0) {
 		PyErr_SetFromErrno(PyExc_OSError);
@@ -1673,7 +1682,7 @@ static PyObject *pyrf_evlist__open(struct pyrf_evlist *pevlist,
 
 static PyObject *pyrf_evlist__close(struct pyrf_evlist *pevlist)
 {
-	struct evlist *evlist = &pevlist->evlist;
+	struct evlist *evlist = pevlist->evlist;
 
 	evlist__close(evlist);
 
@@ -1699,7 +1708,7 @@ static PyObject *pyrf_evlist__config(struct pyrf_evlist *pevlist)
 		.no_buffering        = true,
 		.no_inherit          = true,
 	};
-	struct evlist *evlist = &pevlist->evlist;
+	struct evlist *evlist = pevlist->evlist;
 
 	evlist__config(evlist, &opts, &callchain_param);
 	Py_INCREF(Py_None);
@@ -1708,14 +1717,14 @@ static PyObject *pyrf_evlist__config(struct pyrf_evlist *pevlist)
 
 static PyObject *pyrf_evlist__disable(struct pyrf_evlist *pevlist)
 {
-	evlist__disable(&pevlist->evlist);
+	evlist__disable(pevlist->evlist);
 	Py_INCREF(Py_None);
 	return Py_None;
 }
 
 static PyObject *pyrf_evlist__enable(struct pyrf_evlist *pevlist)
 {
-	evlist__enable(&pevlist->evlist);
+	evlist__enable(pevlist->evlist);
 	Py_INCREF(Py_None);
 	return Py_None;
 }
@@ -1806,7 +1815,26 @@ static Py_ssize_t pyrf_evlist__length(PyObject *obj)
 {
 	struct pyrf_evlist *pevlist = (void *)obj;
 
-	return pevlist->evlist.core.nr_entries;
+	if (!pevlist->evlist)
+		return 0;
+
+	return pevlist->evlist->core.nr_entries;
+}
+
+static PyObject *pyrf_evsel__from_evsel(struct evsel *evsel)
+{
+	struct pyrf_evsel *pevsel = PyObject_New(struct pyrf_evsel, &pyrf_evsel__type);
+
+	if (!pevsel)
+		return NULL;
+
+	memset(&pevsel->evsel, 0, sizeof(pevsel->evsel));
+	evsel__init(&pevsel->evsel, &evsel->core.attr, evsel->core.idx);
+
+	evsel__clone(&pevsel->evsel, evsel);
+	if (evsel__is_group_leader(evsel))
+		evsel__set_leader(&pevsel->evsel, &pevsel->evsel);
+	return (PyObject *)pevsel;
 }
 
 static PyObject *pyrf_evlist__item(PyObject *obj, Py_ssize_t i)
@@ -1814,17 +1842,16 @@ static PyObject *pyrf_evlist__item(PyObject *obj, Py_ssize_t i)
 	struct pyrf_evlist *pevlist = (void *)obj;
 	struct evsel *pos;
 
-	if (i >= pevlist->evlist.core.nr_entries) {
+	if (!pevlist->evlist || i >= pevlist->evlist->core.nr_entries) {
 		PyErr_SetString(PyExc_IndexError, "Index out of range");
 		return NULL;
 	}
 
-	evlist__for_each_entry(&pevlist->evlist, pos) {
+	evlist__for_each_entry(pevlist->evlist, pos) {
 		if (i-- == 0)
 			break;
 	}
-
-	return Py_BuildValue("O", container_of(pos, struct pyrf_evsel, evsel));
+	return pyrf_evsel__from_evsel(pos);
 }
 
 static PyObject *pyrf_evlist__str(PyObject *self)
@@ -1835,8 +1862,11 @@ static PyObject *pyrf_evlist__str(PyObject *self)
 	bool first = true;
 	PyObject *result;
 
+	if (!pevlist->evlist)
+		return PyUnicode_FromString("evlist(uninitialized)");
+
 	strbuf_addstr(&sb, "evlist([");
-	evlist__for_each_entry(&pevlist->evlist, pos) {
+	evlist__for_each_entry(pevlist->evlist, pos) {
 		if (!first)
 			strbuf_addch(&sb, ',');
 		if (!pos->pmu)
@@ -1858,6 +1888,24 @@ static PySequenceMethods pyrf_evlist__sequence_methods = {
 
 static const char pyrf_evlist__doc[] = PyDoc_STR("perf event selector list object.");
 
+static PyObject *pyrf_evlist__getattro(struct pyrf_evlist *pevlist, PyObject *attr_name)
+{
+	if (!pevlist->evlist) {
+		PyErr_SetString(PyExc_ValueError, "evlist not initialized");
+		return NULL;
+	}
+	return PyObject_GenericGetAttr((PyObject *) pevlist, attr_name);
+}
+
+static int pyrf_evlist__setattro(struct pyrf_evlist *pevlist, PyObject *attr_name, PyObject *value)
+{
+	if (!pevlist->evlist) {
+		PyErr_SetString(PyExc_ValueError, "evlist not initialized");
+		return -1;
+	}
+	return PyObject_GenericSetAttr((PyObject *) pevlist, attr_name, value);
+}
+
 static PyTypeObject pyrf_evlist__type = {
 	PyVarObject_HEAD_INIT(NULL, 0)
 	.tp_name	= "perf.evlist",
@@ -1870,11 +1918,23 @@ static PyTypeObject pyrf_evlist__type = {
 	.tp_init	= (initproc)pyrf_evlist__init,
 	.tp_repr        = pyrf_evlist__str,
 	.tp_str         = pyrf_evlist__str,
+	.tp_getattro	= (getattrofunc) pyrf_evlist__getattro,
+	.tp_setattro	= (setattrofunc) pyrf_evlist__setattro,
 };
 
+static PyObject *pyrf_evlist__new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
+{
+	struct pyrf_evlist *pevlist;
+
+	pevlist = (struct pyrf_evlist *)PyType_GenericNew(type, args, kwargs);
+	if (pevlist)
+		pevlist->evlist = NULL;
+	return (PyObject *)pevlist;
+}
+
 static int pyrf_evlist__setup_types(void)
 {
-	pyrf_evlist__type.tp_new = PyType_GenericNew;
+	pyrf_evlist__type.tp_new = pyrf_evlist__new;
 	return PyType_Ready(&pyrf_evlist__type);
 }
 
@@ -1977,157 +2037,74 @@ static PyObject *pyrf__tracepoint(struct pyrf_evsel *pevsel,
 	return PyLong_FromLong(tp_pmu__id(sys, name));
 }
 
-static PyObject *pyrf_evsel__from_evsel(struct evsel *evsel)
-{
-	struct pyrf_evsel *pevsel = PyObject_New(struct pyrf_evsel, &pyrf_evsel__type);
-
-	if (!pevsel)
-		return NULL;
-
-	memset(&pevsel->evsel, 0, sizeof(pevsel->evsel));
-	evsel__init(&pevsel->evsel, &evsel->core.attr, evsel->core.idx);
-
-	evsel__clone(&pevsel->evsel, evsel);
-	if (evsel__is_group_leader(evsel))
-		evsel__set_leader(&pevsel->evsel, &pevsel->evsel);
-	return (PyObject *)pevsel;
-}
-
-static int evlist__pos(struct evlist *evlist, struct evsel *evsel)
-{
-	struct evsel *pos;
-	int idx = 0;
-
-	evlist__for_each_entry(evlist, pos) {
-		if (evsel == pos)
-			return idx;
-		idx++;
-	}
-	return -1;
-}
-
-static struct evsel *evlist__at(struct evlist *evlist, int idx)
-{
-	struct evsel *pos;
-	int idx2 = 0;
-
-	evlist__for_each_entry(evlist, pos) {
-		if (idx == idx2)
-			return pos;
-		idx2++;
-	}
-	return NULL;
-}
-
 static PyObject *pyrf_evlist__from_evlist(struct evlist *evlist)
 {
 	struct pyrf_evlist *pevlist = PyObject_New(struct pyrf_evlist, &pyrf_evlist__type);
-	struct evsel *pos;
-	struct rb_node *node;
 
 	if (!pevlist)
 		return NULL;
 
-	memset(&pevlist->evlist, 0, sizeof(pevlist->evlist));
-	evlist__init(&pevlist->evlist, evlist->core.all_cpus, evlist->core.threads);
-	evlist__for_each_entry(evlist, pos) {
-		struct pyrf_evsel *pevsel = (void *)pyrf_evsel__from_evsel(pos);
-
-		evlist__add(&pevlist->evlist, &pevsel->evsel);
-	}
-	evlist__for_each_entry(&pevlist->evlist, pos) {
-		struct evsel *leader = evsel__leader(pos);
-
-		if (pos != leader) {
-			int idx = evlist__pos(evlist, leader);
-
-			if (idx >= 0)
-				evsel__set_leader(pos, evlist__at(&pevlist->evlist, idx));
-			else if (leader == NULL)
-				evsel__set_leader(pos, pos);
-		}
-
-		leader = pos->metric_leader;
-
-		if (pos != leader) {
-			int idx = evlist__pos(evlist, leader);
-
-			if (idx >= 0)
-				pos->metric_leader = evlist__at(&pevlist->evlist, idx);
-			else if (leader == NULL)
-				pos->metric_leader = pos;
-		}
-	}
-	metricgroup__copy_metric_events(&pevlist->evlist, /*cgrp=*/NULL,
-					&pevlist->evlist.metric_events,
-					&evlist->metric_events);
-	for (node = rb_first_cached(&pevlist->evlist.metric_events.entries); node;
-	     node = rb_next(node)) {
-		struct metric_event *me = container_of(node, struct metric_event, nd);
-		struct list_head *mpos;
-		int idx = evlist__pos(evlist, me->evsel);
-
-		if (idx >= 0)
-			me->evsel = evlist__at(&pevlist->evlist, idx);
-		list_for_each(mpos, &me->head) {
-			struct metric_expr *e = container_of(mpos, struct metric_expr, nd);
-
-			for (int j = 0; e->metric_events[j]; j++) {
-				idx = evlist__pos(evlist, e->metric_events[j]);
-				if (idx >= 0)
-					e->metric_events[j] = evlist__at(&pevlist->evlist, idx);
-			}
-		}
-	}
+	pevlist->evlist = evlist__get(evlist);
 	return (PyObject *)pevlist;
 }
 
 static PyObject *pyrf__parse_events(PyObject *self, PyObject *args)
 {
 	const char *input;
-	struct evlist evlist = {};
+	struct evlist *evlist = evlist__new();
 	struct parse_events_error err;
 	PyObject *result;
 	PyObject *pcpus = NULL, *pthreads = NULL;
 	struct perf_cpu_map *cpus;
 	struct perf_thread_map *threads;
 
-	if (!PyArg_ParseTuple(args, "s|OO", &input, &pcpus, &pthreads))
+	if (!evlist)
+		return PyErr_NoMemory();
+
+	if (!PyArg_ParseTuple(args, "s|OO", &input, &pcpus, &pthreads)) {
+		evlist__put(evlist);
 		return NULL;
+	}
 
 	threads = pthreads ? ((struct pyrf_thread_map *)pthreads)->threads : NULL;
 	cpus = pcpus ? ((struct pyrf_cpu_map *)pcpus)->cpus : NULL;
 
 	parse_events_error__init(&err);
-	evlist__init(&evlist, cpus, threads);
-	if (parse_events(&evlist, input, &err)) {
+	perf_evlist__set_maps(&evlist->core, cpus, threads);
+	if (parse_events(evlist, input, &err)) {
 		parse_events_error__print(&err, input);
 		PyErr_SetFromErrno(PyExc_OSError);
+		evlist__put(evlist);
 		return NULL;
 	}
-	result = pyrf_evlist__from_evlist(&evlist);
-	evlist__exit(&evlist);
+	result = pyrf_evlist__from_evlist(evlist);
+	evlist__put(evlist);
 	return result;
 }
 
 static PyObject *pyrf__parse_metrics(PyObject *self, PyObject *args)
 {
 	const char *input, *pmu = NULL;
-	struct evlist evlist = {};
+	struct evlist *evlist = evlist__new();
 	PyObject *result;
 	PyObject *pcpus = NULL, *pthreads = NULL;
 	struct perf_cpu_map *cpus;
 	struct perf_thread_map *threads;
 	int ret;
 
-	if (!PyArg_ParseTuple(args, "s|sOO", &input, &pmu, &pcpus, &pthreads))
+	if (!evlist)
+		return PyErr_NoMemory();
+
+	if (!PyArg_ParseTuple(args, "s|sOO", &input, &pmu, &pcpus, &pthreads)) {
+		evlist__put(evlist);
 		return NULL;
+	}
 
 	threads = pthreads ? ((struct pyrf_thread_map *)pthreads)->threads : NULL;
 	cpus = pcpus ? ((struct pyrf_cpu_map *)pcpus)->cpus : NULL;
 
-	evlist__init(&evlist, cpus, threads);
-	ret = metricgroup__parse_groups(&evlist, pmu ?: "all", input,
+	perf_evlist__set_maps(&evlist->core, cpus, threads);
+	ret = metricgroup__parse_groups(evlist, pmu ?: "all", input,
 					/*metric_no_group=*/ false,
 					/*metric_no_merge=*/ false,
 					/*metric_no_threshold=*/ true,
@@ -2135,12 +2112,13 @@ static PyObject *pyrf__parse_metrics(PyObject *self, PyObject *args)
 					/*system_wide=*/true,
 					/*hardware_aware_grouping=*/ false);
 	if (ret) {
+		evlist__put(evlist);
 		errno = -ret;
 		PyErr_SetFromErrno(PyExc_OSError);
 		return NULL;
 	}
-	result = pyrf_evlist__from_evlist(&evlist);
-	evlist__exit(&evlist);
+	result = pyrf_evlist__from_evlist(evlist);
+	evlist__put(evlist);
 	return result;
 }