linux/tools/perf/util/cgroup.c
Namhyung Kim d1277aa36b perf cgroup: Maintain cgroup hierarchy
Each cgroup is kept in the perf_env's cgroup_tree sorted by the cgroup
id.  Hist entries have cgroup id can compare it directly and later it
can be used to find a group name using this tree.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20200325124536.2800725-5-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-04-03 09:37:55 -03:00

274 lines
5.3 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <subcmd/parse-options.h>
#include "evsel.h"
#include "cgroup.h"
#include "evlist.h"
#include <linux/zalloc.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <api/fs/fs.h>
int nr_cgroups;
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;
}
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)
{
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:
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);
}
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)
{
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);
}
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 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);
}