Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 251 insertions, 0 deletions

diff --git a/tools/perf/util/cgroup.c b/tools/perf/util/cgroup.c
new file mode 100644
index 000000000..ccd02634a
--- /dev/null
+++ b/tools/perf/util/cgroup.c
@@ -0,0 +1,251 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "util.h"
+#include "../perf.h"
+#include <subcmd/parse-options.h>
+#include "evsel.h"
+#include "cgroup.h"
+#include "evlist.h"
+#include <linux/stringify.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+int nr_cgroups;
+
+static int
+cgroupfs_find_mountpoint(char *buf, size_t maxlen)
+{
+	FILE *fp;
+	char mountpoint[PATH_MAX + 1], tokens[PATH_MAX + 1], type[PATH_MAX + 1];
+	char path_v1[PATH_MAX + 1], path_v2[PATH_MAX + 2], *path;
+	char *token, *saved_ptr = NULL;
+
+	fp = fopen("/proc/mounts", "r");
+	if (!fp)
+		return -1;
+
+	/*
+	 * in order to handle split hierarchy, we need to scan /proc/mounts
+	 * and inspect every cgroupfs mount point to find one that has
+	 * perf_event subsystem
+	 */
+	path_v1[0] = '\0';
+	path_v2[0] = '\0';
+
+	while (fscanf(fp, "%*s %"__stringify(PATH_MAX)"s %"__stringify(PATH_MAX)"s %"
+				__stringify(PATH_MAX)"s %*d %*d\n",
+				mountpoint, type, tokens) == 3) {
+
+		if (!path_v1[0] && !strcmp(type, "cgroup")) {
+
+			token = strtok_r(tokens, ",", &saved_ptr);
+
+			while (token != NULL) {
+				if (!strcmp(token, "perf_event")) {
+					strcpy(path_v1, mountpoint);
+					break;
+				}
+				token = strtok_r(NULL, ",", &saved_ptr);
+			}
+		}
+
+		if (!path_v2[0] && !strcmp(type, "cgroup2"))
+			strcpy(path_v2, mountpoint);
+
+		if (path_v1[0] && path_v2[0])
+			break;
+	}
+	fclose(fp);
+
+	if (path_v1[0])
+		path = path_v1;
+	else if (path_v2[0])
+		path = path_v2;
+	else
+		return -1;
+
+	if (strlen(path) < maxlen) {
+		strcpy(buf, path);
+		return 0;
+	}
+	return -1;
+}
+
+static int open_cgroup(const char *name)
+{
+	char path[PATH_MAX + 1];
+	char mnt[PATH_MAX + 1];
+	int fd;
+
+
+	if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1))
+		return -1;
+
+	scnprintf(path, PATH_MAX, "%s/%s", mnt, name);
+
+	fd = open(path, O_RDONLY);
+	if (fd == -1)
+		fprintf(stderr, "no access to cgroup %s\n", path);
+
+	return fd;
+}
+
+static struct cgroup *evlist__find_cgroup(struct perf_evlist *evlist, const char *str)
+{
+	struct perf_evsel *counter;
+	/*
+	 * check if cgrp is already defined, if so we reuse it
+	 */
+	evlist__for_each_entry(evlist, counter) {
+		if (!counter->cgrp)
+			continue;
+		if (!strcmp(counter->cgrp->name, str))
+			return cgroup__get(counter->cgrp);
+	}
+
+	return NULL;
+}
+
+static struct cgroup *cgroup__new(const char *name)
+{
+	struct cgroup *cgroup = zalloc(sizeof(*cgroup));
+
+	if (cgroup != NULL) {
+		refcount_set(&cgroup->refcnt, 1);
+
+		cgroup->name = strdup(name);
+		if (!cgroup->name)
+			goto out_err;
+		cgroup->fd = open_cgroup(name);
+		if (cgroup->fd == -1)
+			goto out_free_name;
+	}
+
+	return cgroup;
+
+out_free_name:
+	free(cgroup->name);
+out_err:
+	free(cgroup);
+	return NULL;
+}
+
+struct cgroup *evlist__findnew_cgroup(struct perf_evlist *evlist, const char *name)
+{
+	struct cgroup *cgroup = evlist__find_cgroup(evlist, name);
+
+	return cgroup ?: cgroup__new(name);
+}
+
+static int add_cgroup(struct perf_evlist *evlist, const char *str)
+{
+	struct perf_evsel *counter;
+	struct cgroup *cgrp = evlist__findnew_cgroup(evlist, str);
+	int n;
+
+	if (!cgrp)
+		return -1;
+	/*
+	 * find corresponding event
+	 * if add cgroup N, then need to find event N
+	 */
+	n = 0;
+	evlist__for_each_entry(evlist, counter) {
+		if (n == nr_cgroups)
+			goto found;
+		n++;
+	}
+
+	cgroup__put(cgrp);
+	return -1;
+found:
+	counter->cgrp = cgrp;
+	return 0;
+}
+
+static void cgroup__delete(struct cgroup *cgroup)
+{
+	close(cgroup->fd);
+	zfree(&cgroup->name);
+	free(cgroup);
+}
+
+void cgroup__put(struct cgroup *cgrp)
+{
+	if (cgrp && refcount_dec_and_test(&cgrp->refcnt)) {
+		cgroup__delete(cgrp);
+	}
+}
+
+struct cgroup *cgroup__get(struct cgroup *cgroup)
+{
+       if (cgroup)
+		refcount_inc(&cgroup->refcnt);
+       return cgroup;
+}
+
+static void evsel__set_default_cgroup(struct perf_evsel *evsel, struct cgroup *cgroup)
+{
+	if (evsel->cgrp == NULL)
+		evsel->cgrp = cgroup__get(cgroup);
+}
+
+void evlist__set_default_cgroup(struct perf_evlist *evlist, struct cgroup *cgroup)
+{
+	struct perf_evsel *evsel;
+
+	evlist__for_each_entry(evlist, evsel)
+		evsel__set_default_cgroup(evsel, cgroup);
+}
+
+int parse_cgroups(const struct option *opt, const char *str,
+		  int unset __maybe_unused)
+{
+	struct perf_evlist *evlist = *(struct perf_evlist **)opt->value;
+	struct perf_evsel *counter;
+	struct cgroup *cgrp = NULL;
+	const char *p, *e, *eos = str + strlen(str);
+	char *s;
+	int ret, i;
+
+	if (list_empty(&evlist->entries)) {
+		fprintf(stderr, "must define events before cgroups\n");
+		return -1;
+	}
+
+	for (;;) {
+		p = strchr(str, ',');
+		e = p ? p : eos;
+
+		/* allow empty cgroups, i.e., skip */
+		if (e - str) {
+			/* termination added */
+			s = strndup(str, e - str);
+			if (!s)
+				return -1;
+			ret = add_cgroup(evlist, s);
+			free(s);
+			if (ret)
+				return -1;
+		}
+		/* nr_cgroups is increased een for empty cgroups */
+		nr_cgroups++;
+		if (!p)
+			break;
+		str = p+1;
+	}
+	/* for the case one cgroup combine to multiple events */
+	i = 0;
+	if (nr_cgroups == 1) {
+		evlist__for_each_entry(evlist, counter) {
+			if (i == 0)
+				cgrp = counter->cgrp;
+			else {
+				counter->cgrp = cgrp;
+				refcount_inc(&cgrp->refcnt);
+			}
+			i++;
+		}
+	}
+	return 0;
+}