linux/tools/perf/util/cgroup.c
Irina Tirdea 1d037ca164 perf tools: Use __maybe_used for unused variables
perf defines both __used and __unused variables to use for marking
unused variables. The variable __used is defined to
__attribute__((__unused__)), which contradicts the kernel definition to
__attribute__((__used__)) for new gcc versions. On Android, __used is
also defined in system headers and this leads to warnings like: warning:
'__used__' attribute ignored

__unused is not defined in the kernel and is not a standard definition.
If __unused is included everywhere instead of __used, this leads to
conflicts with glibc headers, since glibc has a variables with this name
in its headers.

The best approach is to use __maybe_unused, the definition used in the
kernel for __attribute__((unused)). In this way there is only one
definition in perf sources (instead of 2 definitions that point to the
same thing: __used and __unused) and it works on both Linux and Android.
This patch simply replaces all instances of __used and __unused with
__maybe_unused.

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1347315303-29906-7-git-send-email-irina.tirdea@intel.com
[ committer note: fixed up conflict with a116e05 in builtin-sched.c ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2012-09-11 12:19:15 -03:00

178 lines
3.1 KiB
C

#include "util.h"
#include "../perf.h"
#include "parse-options.h"
#include "evsel.h"
#include "cgroup.h"
#include "evlist.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 *token, *saved_ptr = NULL;
int found = 0;
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
*/
while (fscanf(fp, "%*s %"STR(PATH_MAX)"s %"STR(PATH_MAX)"s %"
STR(PATH_MAX)"s %*d %*d\n",
mountpoint, type, tokens) == 3) {
if (!strcmp(type, "cgroup")) {
token = strtok_r(tokens, ",", &saved_ptr);
while (token != NULL) {
if (!strcmp(token, "perf_event")) {
found = 1;
break;
}
token = strtok_r(NULL, ",", &saved_ptr);
}
}
if (found)
break;
}
fclose(fp);
if (!found)
return -1;
if (strlen(mountpoint) < maxlen) {
strcpy(buf, mountpoint);
return 0;
}
return -1;
}
static int open_cgroup(char *name)
{
char path[PATH_MAX + 1];
char mnt[PATH_MAX + 1];
int fd;
if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1))
return -1;
snprintf(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 int add_cgroup(struct perf_evlist *evlist, char *str)
{
struct perf_evsel *counter;
struct cgroup_sel *cgrp = NULL;
int n;
/*
* check if cgrp is already defined, if so we reuse it
*/
list_for_each_entry(counter, &evlist->entries, node) {
cgrp = counter->cgrp;
if (!cgrp)
continue;
if (!strcmp(cgrp->name, str))
break;
cgrp = NULL;
}
if (!cgrp) {
cgrp = zalloc(sizeof(*cgrp));
if (!cgrp)
return -1;
cgrp->name = str;
cgrp->fd = open_cgroup(str);
if (cgrp->fd == -1) {
free(cgrp);
return -1;
}
}
/*
* find corresponding event
* if add cgroup N, then need to find event N
*/
n = 0;
list_for_each_entry(counter, &evlist->entries, node) {
if (n == nr_cgroups)
goto found;
n++;
}
if (cgrp->refcnt == 0)
free(cgrp);
return -1;
found:
cgrp->refcnt++;
counter->cgrp = cgrp;
return 0;
}
void close_cgroup(struct cgroup_sel *cgrp)
{
if (!cgrp)
return;
/* XXX: not reentrant */
if (--cgrp->refcnt == 0) {
close(cgrp->fd);
free(cgrp->name);
free(cgrp);
}
}
int parse_cgroups(const struct option *opt __maybe_unused, const char *str,
int unset __maybe_unused)
{
struct perf_evlist *evlist = *(struct perf_evlist **)opt->value;
const char *p, *e, *eos = str + strlen(str);
char *s;
int ret;
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);
if (ret) {
free(s);
return -1;
}
}
/* nr_cgroups is increased een for empty cgroups */
nr_cgroups++;
if (!p)
break;
str = p+1;
}
return 0;
}