1 #include "util.h" 2 #include "../perf.h" 3 #include <subcmd/parse-options.h> 4 #include "evsel.h" 5 #include "cgroup.h" 6 #include "evlist.h" 7 8 int nr_cgroups; 9 10 static int 11 cgroupfs_find_mountpoint(char *buf, size_t maxlen) 12 { 13 FILE *fp; 14 char mountpoint[PATH_MAX + 1], tokens[PATH_MAX + 1], type[PATH_MAX + 1]; 15 char path_v1[PATH_MAX + 1], path_v2[PATH_MAX + 2], *path; 16 char *token, *saved_ptr = NULL; 17 18 fp = fopen("/proc/mounts", "r"); 19 if (!fp) 20 return -1; 21 22 /* 23 * in order to handle split hierarchy, we need to scan /proc/mounts 24 * and inspect every cgroupfs mount point to find one that has 25 * perf_event subsystem 26 */ 27 path_v1[0] = '\0'; 28 path_v2[0] = '\0'; 29 30 while (fscanf(fp, "%*s %"STR(PATH_MAX)"s %"STR(PATH_MAX)"s %" 31 STR(PATH_MAX)"s %*d %*d\n", 32 mountpoint, type, tokens) == 3) { 33 34 if (!path_v1[0] && !strcmp(type, "cgroup")) { 35 36 token = strtok_r(tokens, ",", &saved_ptr); 37 38 while (token != NULL) { 39 if (!strcmp(token, "perf_event")) { 40 strcpy(path_v1, mountpoint); 41 break; 42 } 43 token = strtok_r(NULL, ",", &saved_ptr); 44 } 45 } 46 47 if (!path_v2[0] && !strcmp(type, "cgroup2")) 48 strcpy(path_v2, mountpoint); 49 50 if (path_v1[0] && path_v2[0]) 51 break; 52 } 53 fclose(fp); 54 55 if (path_v1[0]) 56 path = path_v1; 57 else if (path_v2[0]) 58 path = path_v2; 59 else 60 return -1; 61 62 if (strlen(path) < maxlen) { 63 strcpy(buf, path); 64 return 0; 65 } 66 return -1; 67 } 68 69 static int open_cgroup(char *name) 70 { 71 char path[PATH_MAX + 1]; 72 char mnt[PATH_MAX + 1]; 73 int fd; 74 75 76 if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1)) 77 return -1; 78 79 snprintf(path, PATH_MAX, "%s/%s", mnt, name); 80 81 fd = open(path, O_RDONLY); 82 if (fd == -1) 83 fprintf(stderr, "no access to cgroup %s\n", path); 84 85 return fd; 86 } 87 88 static int add_cgroup(struct perf_evlist *evlist, char *str) 89 { 90 struct perf_evsel *counter; 91 struct cgroup_sel *cgrp = NULL; 92 int n; 93 /* 94 * check if cgrp is already defined, if so we reuse it 95 */ 96 evlist__for_each_entry(evlist, counter) { 97 cgrp = counter->cgrp; 98 if (!cgrp) 99 continue; 100 if (!strcmp(cgrp->name, str)) 101 break; 102 103 cgrp = NULL; 104 } 105 106 if (!cgrp) { 107 cgrp = zalloc(sizeof(*cgrp)); 108 if (!cgrp) 109 return -1; 110 111 cgrp->name = str; 112 113 cgrp->fd = open_cgroup(str); 114 if (cgrp->fd == -1) { 115 free(cgrp); 116 return -1; 117 } 118 } 119 120 /* 121 * find corresponding event 122 * if add cgroup N, then need to find event N 123 */ 124 n = 0; 125 evlist__for_each_entry(evlist, counter) { 126 if (n == nr_cgroups) 127 goto found; 128 n++; 129 } 130 if (atomic_read(&cgrp->refcnt) == 0) 131 free(cgrp); 132 133 return -1; 134 found: 135 atomic_inc(&cgrp->refcnt); 136 counter->cgrp = cgrp; 137 return 0; 138 } 139 140 void close_cgroup(struct cgroup_sel *cgrp) 141 { 142 if (cgrp && atomic_dec_and_test(&cgrp->refcnt)) { 143 close(cgrp->fd); 144 zfree(&cgrp->name); 145 free(cgrp); 146 } 147 } 148 149 int parse_cgroups(const struct option *opt __maybe_unused, const char *str, 150 int unset __maybe_unused) 151 { 152 struct perf_evlist *evlist = *(struct perf_evlist **)opt->value; 153 const char *p, *e, *eos = str + strlen(str); 154 char *s; 155 int ret; 156 157 if (list_empty(&evlist->entries)) { 158 fprintf(stderr, "must define events before cgroups\n"); 159 return -1; 160 } 161 162 for (;;) { 163 p = strchr(str, ','); 164 e = p ? p : eos; 165 166 /* allow empty cgroups, i.e., skip */ 167 if (e - str) { 168 /* termination added */ 169 s = strndup(str, e - str); 170 if (!s) 171 return -1; 172 ret = add_cgroup(evlist, s); 173 if (ret) { 174 free(s); 175 return -1; 176 } 177 } 178 /* nr_cgroups is increased een for empty cgroups */ 179 nr_cgroups++; 180 if (!p) 181 break; 182 str = p+1; 183 } 184 return 0; 185 } 186