174 lines
3.1 KiB
C
174 lines
3.1 KiB
C
#include "util.h"
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#include "../perf.h"
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#include <subcmd/parse-options.h>
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#include "evsel.h"
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#include "cgroup.h"
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#include "evlist.h"
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int nr_cgroups;
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static int
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cgroupfs_find_mountpoint(char *buf, size_t maxlen)
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{
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FILE *fp;
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char mountpoint[PATH_MAX + 1], tokens[PATH_MAX + 1], type[PATH_MAX + 1];
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char *token, *saved_ptr = NULL;
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int found = 0;
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fp = fopen("/proc/mounts", "r");
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if (!fp)
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return -1;
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/*
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* in order to handle split hierarchy, we need to scan /proc/mounts
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* and inspect every cgroupfs mount point to find one that has
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* perf_event subsystem
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*/
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while (fscanf(fp, "%*s %"STR(PATH_MAX)"s %"STR(PATH_MAX)"s %"
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STR(PATH_MAX)"s %*d %*d\n",
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mountpoint, type, tokens) == 3) {
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if (!strcmp(type, "cgroup")) {
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token = strtok_r(tokens, ",", &saved_ptr);
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while (token != NULL) {
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if (!strcmp(token, "perf_event")) {
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found = 1;
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break;
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}
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token = strtok_r(NULL, ",", &saved_ptr);
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}
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}
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if (found)
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break;
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}
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fclose(fp);
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if (!found)
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return -1;
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if (strlen(mountpoint) < maxlen) {
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strcpy(buf, mountpoint);
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return 0;
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}
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return -1;
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}
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static int open_cgroup(char *name)
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{
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char path[PATH_MAX + 1];
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char mnt[PATH_MAX + 1];
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int fd;
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if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1))
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return -1;
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snprintf(path, PATH_MAX, "%s/%s", mnt, name);
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fd = open(path, O_RDONLY);
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if (fd == -1)
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fprintf(stderr, "no access to cgroup %s\n", path);
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return fd;
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}
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static int add_cgroup(struct perf_evlist *evlist, char *str)
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{
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struct perf_evsel *counter;
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struct cgroup_sel *cgrp = NULL;
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int n;
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/*
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* check if cgrp is already defined, if so we reuse it
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*/
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evlist__for_each_entry(evlist, counter) {
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cgrp = counter->cgrp;
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if (!cgrp)
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continue;
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if (!strcmp(cgrp->name, str))
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break;
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cgrp = NULL;
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}
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if (!cgrp) {
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cgrp = zalloc(sizeof(*cgrp));
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if (!cgrp)
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return -1;
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cgrp->name = str;
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cgrp->fd = open_cgroup(str);
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if (cgrp->fd == -1) {
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free(cgrp);
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return -1;
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}
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}
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/*
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* find corresponding event
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* if add cgroup N, then need to find event N
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*/
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n = 0;
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evlist__for_each_entry(evlist, counter) {
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if (n == nr_cgroups)
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goto found;
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n++;
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}
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if (atomic_read(&cgrp->refcnt) == 0)
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free(cgrp);
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return -1;
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found:
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atomic_inc(&cgrp->refcnt);
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counter->cgrp = cgrp;
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return 0;
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}
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void close_cgroup(struct cgroup_sel *cgrp)
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{
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if (cgrp && atomic_dec_and_test(&cgrp->refcnt)) {
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close(cgrp->fd);
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zfree(&cgrp->name);
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free(cgrp);
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}
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}
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int parse_cgroups(const struct option *opt __maybe_unused, const char *str,
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int unset __maybe_unused)
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{
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struct perf_evlist *evlist = *(struct perf_evlist **)opt->value;
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const char *p, *e, *eos = str + strlen(str);
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char *s;
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int ret;
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if (list_empty(&evlist->entries)) {
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fprintf(stderr, "must define events before cgroups\n");
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return -1;
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}
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for (;;) {
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p = strchr(str, ',');
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e = p ? p : eos;
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/* allow empty cgroups, i.e., skip */
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if (e - str) {
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/* termination added */
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s = strndup(str, e - str);
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if (!s)
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return -1;
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ret = add_cgroup(evlist, s);
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if (ret) {
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free(s);
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return -1;
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}
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}
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/* nr_cgroups is increased een for empty cgroups */
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nr_cgroups++;
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if (!p)
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break;
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str = p+1;
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}
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return 0;
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}
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