linux-zen-desktop/tools/perf/util/cgroup.c

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2023-08-30 17:31:07 +02:00
// SPDX-License-Identifier: GPL-2.0
#include <subcmd/parse-options.h>
#include "evsel.h"
#include "cgroup.h"
#include "evlist.h"
#include "rblist.h"
#include "metricgroup.h"
#include "stat.h"
#include <linux/zalloc.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/statfs.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <api/fs/fs.h>
#include <ftw.h>
#include <regex.h>
int nr_cgroups;
bool cgrp_event_expanded;
/* used to match cgroup name with patterns */
struct cgroup_name {
struct list_head list;
bool used;
char name[];
};
static LIST_HEAD(cgroup_list);
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, "perf_event"))
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;
}
#ifdef HAVE_FILE_HANDLE
int read_cgroup_id(struct cgroup *cgrp)
{
char path[PATH_MAX + 1];
char mnt[PATH_MAX + 1];
struct {
struct file_handle fh;
uint64_t cgroup_id;
} handle;
int mount_id;
if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1, "perf_event"))
return -1;
scnprintf(path, PATH_MAX, "%s/%s", mnt, cgrp->name);
handle.fh.handle_bytes = sizeof(handle.cgroup_id);
if (name_to_handle_at(AT_FDCWD, path, &handle.fh, &mount_id, 0) < 0)
return -1;
cgrp->id = handle.cgroup_id;
return 0;
}
#endif /* HAVE_FILE_HANDLE */
#ifndef CGROUP2_SUPER_MAGIC
#define CGROUP2_SUPER_MAGIC 0x63677270
#endif
int cgroup_is_v2(const char *subsys)
{
char mnt[PATH_MAX + 1];
struct statfs stbuf;
if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1, subsys))
return -1;
if (statfs(mnt, &stbuf) < 0)
return -1;
return (stbuf.f_type == CGROUP2_SUPER_MAGIC);
}
static struct cgroup *evlist__find_cgroup(struct evlist *evlist, const char *str)
{
struct 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, bool do_open)
{
struct cgroup *cgroup = zalloc(sizeof(*cgroup));
if (cgroup != NULL) {
refcount_set(&cgroup->refcnt, 1);
cgroup->name = strdup(name);
if (!cgroup->name)
goto out_err;
if (do_open) {
cgroup->fd = open_cgroup(name);
if (cgroup->fd == -1)
goto out_free_name;
} else {
cgroup->fd = -1;
}
}
return cgroup;
out_free_name:
zfree(&cgroup->name);
out_err:
free(cgroup);
return NULL;
}
struct cgroup *evlist__findnew_cgroup(struct evlist *evlist, const char *name)
{
struct cgroup *cgroup = evlist__find_cgroup(evlist, name);
return cgroup ?: cgroup__new(name, true);
}
static int add_cgroup(struct evlist *evlist, const char *str)
{
struct 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)
{
if (cgroup->fd >= 0)
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 evsel *evsel, struct cgroup *cgroup)
{
if (evsel->cgrp == NULL)
evsel->cgrp = cgroup__get(cgroup);
}
void evlist__set_default_cgroup(struct evlist *evlist, struct cgroup *cgroup)
{
struct evsel *evsel;
evlist__for_each_entry(evlist, evsel)
evsel__set_default_cgroup(evsel, cgroup);
}
/* helper function for ftw() in match_cgroups and list_cgroups */
static int add_cgroup_name(const char *fpath, const struct stat *sb __maybe_unused,
int typeflag, struct FTW *ftwbuf __maybe_unused)
{
struct cgroup_name *cn;
if (typeflag != FTW_D)
return 0;
cn = malloc(sizeof(*cn) + strlen(fpath) + 1);
if (cn == NULL)
return -1;
cn->used = false;
strcpy(cn->name, fpath);
list_add_tail(&cn->list, &cgroup_list);
return 0;
}
static int check_and_add_cgroup_name(const char *fpath)
{
struct cgroup_name *cn;
list_for_each_entry(cn, &cgroup_list, list) {
if (!strcmp(cn->name, fpath))
return 0;
}
/* pretend if it's added by ftw() */
return add_cgroup_name(fpath, NULL, FTW_D, NULL);
}
static void release_cgroup_list(void)
{
struct cgroup_name *cn;
while (!list_empty(&cgroup_list)) {
cn = list_first_entry(&cgroup_list, struct cgroup_name, list);
list_del(&cn->list);
free(cn);
}
}
/* collect given cgroups only */
static int list_cgroups(const char *str)
{
const char *p, *e, *eos = str + strlen(str);
struct cgroup_name *cn;
char *s;
/* use given name as is when no regex is given */
for (;;) {
p = strchr(str, ',');
e = p ? p : eos;
if (e - str) {
int ret;
s = strndup(str, e - str);
if (!s)
return -1;
ret = check_and_add_cgroup_name(s);
free(s);
if (ret < 0)
return -1;
} else {
if (check_and_add_cgroup_name("/") < 0)
return -1;
}
if (!p)
break;
str = p+1;
}
/* these groups will be used */
list_for_each_entry(cn, &cgroup_list, list)
cn->used = true;
return 0;
}
/* collect all cgroups first and then match with the pattern */
static int match_cgroups(const char *str)
{
char mnt[PATH_MAX];
const char *p, *e, *eos = str + strlen(str);
struct cgroup_name *cn;
regex_t reg;
int prefix_len;
char *s;
if (cgroupfs_find_mountpoint(mnt, sizeof(mnt), "perf_event"))
return -1;
/* cgroup_name will have a full path, skip the root directory */
prefix_len = strlen(mnt);
/* collect all cgroups in the cgroup_list */
if (nftw(mnt, add_cgroup_name, 20, 0) < 0)
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;
if (regcomp(&reg, s, REG_NOSUB)) {
free(s);
return -1;
}
/* check cgroup name with the pattern */
list_for_each_entry(cn, &cgroup_list, list) {
char *name = cn->name + prefix_len;
if (name[0] == '/' && name[1])
name++;
if (!regexec(&reg, name, 0, NULL, 0))
cn->used = true;
}
regfree(&reg);
free(s);
} else {
/* first entry to root cgroup */
cn = list_first_entry(&cgroup_list, struct cgroup_name,
list);
cn->used = true;
}
if (!p)
break;
str = p+1;
}
return prefix_len;
}
int parse_cgroups(const struct option *opt, const char *str,
int unset __maybe_unused)
{
struct evlist *evlist = *(struct evlist **)opt->value;
struct evsel *counter;
struct cgroup *cgrp = NULL;
const char *p, *e, *eos = str + strlen(str);
char *s;
int ret, i;
if (list_empty(&evlist->core.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;
}
static bool has_pattern_string(const char *str)
{
return !!strpbrk(str, "{}[]()|*+?^$");
}
int evlist__expand_cgroup(struct evlist *evlist, const char *str,
struct rblist *metric_events, bool open_cgroup)
{
struct evlist *orig_list, *tmp_list;
struct evsel *pos, *evsel, *leader;
struct rblist orig_metric_events;
struct cgroup *cgrp = NULL;
struct cgroup_name *cn;
int ret = -1;
int prefix_len;
if (evlist->core.nr_entries == 0) {
fprintf(stderr, "must define events before cgroups\n");
return -EINVAL;
}
orig_list = evlist__new();
tmp_list = evlist__new();
if (orig_list == NULL || tmp_list == NULL) {
fprintf(stderr, "memory allocation failed\n");
return -ENOMEM;
}
/* save original events and init evlist */
evlist__splice_list_tail(orig_list, &evlist->core.entries);
evlist->core.nr_entries = 0;
if (metric_events) {
orig_metric_events = *metric_events;
rblist__init(metric_events);
} else {
rblist__init(&orig_metric_events);
}
if (has_pattern_string(str))
prefix_len = match_cgroups(str);
else
prefix_len = list_cgroups(str);
if (prefix_len < 0)
goto out_err;
list_for_each_entry(cn, &cgroup_list, list) {
char *name;
if (!cn->used)
continue;
/* cgroup_name might have a full path, skip the prefix */
name = cn->name + prefix_len;
if (name[0] == '/' && name[1])
name++;
cgrp = cgroup__new(name, open_cgroup);
if (cgrp == NULL)
goto out_err;
leader = NULL;
evlist__for_each_entry(orig_list, pos) {
evsel = evsel__clone(pos);
if (evsel == NULL)
goto out_err;
cgroup__put(evsel->cgrp);
evsel->cgrp = cgroup__get(cgrp);
if (evsel__is_group_leader(pos))
leader = evsel;
evsel__set_leader(evsel, leader);
evlist__add(tmp_list, evsel);
}
/* cgroup__new() has a refcount, release it here */
cgroup__put(cgrp);
nr_cgroups++;
if (metric_events) {
if (metricgroup__copy_metric_events(tmp_list, cgrp,
metric_events,
&orig_metric_events) < 0)
goto out_err;
}
evlist__splice_list_tail(evlist, &tmp_list->core.entries);
tmp_list->core.nr_entries = 0;
}
if (list_empty(&evlist->core.entries)) {
fprintf(stderr, "no cgroup matched: %s\n", str);
goto out_err;
}
ret = 0;
cgrp_event_expanded = true;
out_err:
evlist__delete(orig_list);
evlist__delete(tmp_list);
rblist__exit(&orig_metric_events);
release_cgroup_list();
return ret;
}
static struct cgroup *__cgroup__findnew(struct rb_root *root, uint64_t id,
bool create, const char *path)
{
struct rb_node **p = &root->rb_node;
struct rb_node *parent = NULL;
struct cgroup *cgrp;
while (*p != NULL) {
parent = *p;
cgrp = rb_entry(parent, struct cgroup, node);
if (cgrp->id == id)
return cgrp;
if (cgrp->id < id)
p = &(*p)->rb_left;
else
p = &(*p)->rb_right;
}
if (!create)
return NULL;
cgrp = malloc(sizeof(*cgrp));
if (cgrp == NULL)
return NULL;
cgrp->name = strdup(path);
if (cgrp->name == NULL) {
free(cgrp);
return NULL;
}
cgrp->fd = -1;
cgrp->id = id;
refcount_set(&cgrp->refcnt, 1);
rb_link_node(&cgrp->node, parent, p);
rb_insert_color(&cgrp->node, root);
return cgrp;
}
struct cgroup *cgroup__findnew(struct perf_env *env, uint64_t id,
const char *path)
{
struct cgroup *cgrp;
down_write(&env->cgroups.lock);
cgrp = __cgroup__findnew(&env->cgroups.tree, id, true, path);
up_write(&env->cgroups.lock);
return cgrp;
}
struct cgroup *cgroup__find(struct perf_env *env, uint64_t id)
{
struct cgroup *cgrp;
down_read(&env->cgroups.lock);
cgrp = __cgroup__findnew(&env->cgroups.tree, id, false, NULL);
up_read(&env->cgroups.lock);
return cgrp;
}
void perf_env__purge_cgroups(struct perf_env *env)
{
struct rb_node *node;
struct cgroup *cgrp;
down_write(&env->cgroups.lock);
while (!RB_EMPTY_ROOT(&env->cgroups.tree)) {
node = rb_first(&env->cgroups.tree);
cgrp = rb_entry(node, struct cgroup, node);
rb_erase(node, &env->cgroups.tree);
cgroup__put(cgrp);
}
up_write(&env->cgroups.lock);
}