| 1 | /* |
| 2 | * Code related to setting up a blkio cgroup |
| 3 | */ |
| 4 | #include <stdio.h> |
| 5 | #include <stdlib.h> |
| 6 | #include <mntent.h> |
| 7 | #include <sys/stat.h> |
| 8 | #include "fio.h" |
| 9 | #include "flist.h" |
| 10 | #include "cgroup.h" |
| 11 | #include "smalloc.h" |
| 12 | |
| 13 | static struct fio_sem *lock; |
| 14 | |
| 15 | struct cgroup_member { |
| 16 | struct flist_head list; |
| 17 | char *root; |
| 18 | unsigned int cgroup_nodelete; |
| 19 | }; |
| 20 | |
| 21 | static struct cgroup_mnt *find_cgroup_mnt(struct thread_data *td) |
| 22 | { |
| 23 | struct cgroup_mnt *cgroup_mnt = NULL; |
| 24 | struct mntent *mnt, dummy; |
| 25 | char buf[256] = {0}; |
| 26 | FILE *f; |
| 27 | bool cgroup2 = false; |
| 28 | |
| 29 | f = setmntent("/proc/mounts", "r"); |
| 30 | if (!f) { |
| 31 | td_verror(td, errno, "setmntent /proc/mounts"); |
| 32 | return NULL; |
| 33 | } |
| 34 | |
| 35 | while ((mnt = getmntent_r(f, &dummy, buf, sizeof(buf))) != NULL) { |
| 36 | if (!strcmp(mnt->mnt_type, "cgroup") && |
| 37 | strstr(mnt->mnt_opts, "blkio")) |
| 38 | break; |
| 39 | if (!strcmp(mnt->mnt_type, "cgroup2")) { |
| 40 | cgroup2 = true; |
| 41 | break; |
| 42 | } |
| 43 | } |
| 44 | |
| 45 | if (mnt) { |
| 46 | cgroup_mnt = smalloc(sizeof(*cgroup_mnt)); |
| 47 | if (cgroup_mnt) { |
| 48 | cgroup_mnt->path = smalloc_strdup(mnt->mnt_dir); |
| 49 | if (!cgroup_mnt->path) { |
| 50 | sfree(cgroup_mnt); |
| 51 | log_err("fio: could not allocate memory\n"); |
| 52 | } else { |
| 53 | cgroup_mnt->cgroup2 = cgroup2; |
| 54 | } |
| 55 | } |
| 56 | } else { |
| 57 | log_err("fio: cgroup blkio does not appear to be mounted\n"); |
| 58 | } |
| 59 | |
| 60 | endmntent(f); |
| 61 | return cgroup_mnt; |
| 62 | } |
| 63 | |
| 64 | static void add_cgroup(struct thread_data *td, const char *name, |
| 65 | struct flist_head *clist) |
| 66 | { |
| 67 | struct cgroup_member *cm; |
| 68 | |
| 69 | if (!lock) |
| 70 | return; |
| 71 | |
| 72 | cm = smalloc(sizeof(*cm)); |
| 73 | if (!cm) { |
| 74 | err: |
| 75 | log_err("fio: failed to allocate cgroup member\n"); |
| 76 | return; |
| 77 | } |
| 78 | |
| 79 | INIT_FLIST_HEAD(&cm->list); |
| 80 | cm->root = smalloc_strdup(name); |
| 81 | if (!cm->root) { |
| 82 | sfree(cm); |
| 83 | goto err; |
| 84 | } |
| 85 | if (td->o.cgroup_nodelete) |
| 86 | cm->cgroup_nodelete = 1; |
| 87 | fio_sem_down(lock); |
| 88 | flist_add_tail(&cm->list, clist); |
| 89 | fio_sem_up(lock); |
| 90 | } |
| 91 | |
| 92 | void cgroup_kill(struct flist_head *clist) |
| 93 | { |
| 94 | struct flist_head *n, *tmp; |
| 95 | struct cgroup_member *cm; |
| 96 | |
| 97 | if (!lock) |
| 98 | return; |
| 99 | |
| 100 | fio_sem_down(lock); |
| 101 | |
| 102 | flist_for_each_safe(n, tmp, clist) { |
| 103 | cm = flist_entry(n, struct cgroup_member, list); |
| 104 | if (!cm->cgroup_nodelete) |
| 105 | rmdir(cm->root); |
| 106 | flist_del(&cm->list); |
| 107 | sfree(cm->root); |
| 108 | sfree(cm); |
| 109 | } |
| 110 | |
| 111 | fio_sem_up(lock); |
| 112 | } |
| 113 | |
| 114 | static char *get_cgroup_root(struct thread_data *td, struct cgroup_mnt *mnt) |
| 115 | { |
| 116 | char *str = malloc(64); |
| 117 | |
| 118 | if (td->o.cgroup) |
| 119 | sprintf(str, "%s/%s", mnt->path, td->o.cgroup); |
| 120 | else |
| 121 | sprintf(str, "%s/%s", mnt->path, td->o.name); |
| 122 | |
| 123 | return str; |
| 124 | } |
| 125 | |
| 126 | static int write_int_to_file(struct thread_data *td, const char *path, |
| 127 | const char *filename, unsigned int val, |
| 128 | const char *onerr) |
| 129 | { |
| 130 | char tmp[256]; |
| 131 | FILE *f; |
| 132 | |
| 133 | sprintf(tmp, "%s/%s", path, filename); |
| 134 | f = fopen(tmp, "w"); |
| 135 | if (!f) { |
| 136 | td_verror(td, errno, onerr); |
| 137 | return 1; |
| 138 | } |
| 139 | |
| 140 | fprintf(f, "%u", val); |
| 141 | fclose(f); |
| 142 | return 0; |
| 143 | |
| 144 | } |
| 145 | |
| 146 | static int cgroup_write_pid(struct thread_data *td, char *path, bool cgroup2) |
| 147 | { |
| 148 | unsigned int val = td->pid; |
| 149 | |
| 150 | if (cgroup2) |
| 151 | return write_int_to_file(td, path, "cgroup.procs", |
| 152 | val, "cgroup write pid"); |
| 153 | return write_int_to_file(td, path, "tasks", val, "cgroup write pid"); |
| 154 | } |
| 155 | |
| 156 | /* |
| 157 | * Move pid to root class |
| 158 | */ |
| 159 | static int cgroup_del_pid(struct thread_data *td, struct cgroup_mnt *mnt) |
| 160 | { |
| 161 | return cgroup_write_pid(td, mnt->path, mnt->cgroup2); |
| 162 | } |
| 163 | |
| 164 | int cgroup_setup(struct thread_data *td, struct flist_head *clist, struct cgroup_mnt **mnt) |
| 165 | { |
| 166 | char *root; |
| 167 | |
| 168 | if (!clist) |
| 169 | return 1; |
| 170 | |
| 171 | if (!*mnt) { |
| 172 | *mnt = find_cgroup_mnt(td); |
| 173 | if (!*mnt) |
| 174 | return 1; |
| 175 | } |
| 176 | |
| 177 | /* |
| 178 | * Create container, if it doesn't exist |
| 179 | */ |
| 180 | root = get_cgroup_root(td, *mnt); |
| 181 | if (mkdir(root, 0755) < 0) { |
| 182 | int __e = errno; |
| 183 | |
| 184 | if (__e != EEXIST) { |
| 185 | td_verror(td, __e, "cgroup mkdir"); |
| 186 | log_err("fio: path %s\n", root); |
| 187 | goto err; |
| 188 | } |
| 189 | } else |
| 190 | add_cgroup(td, root, clist); |
| 191 | |
| 192 | if (td->o.cgroup_weight) { |
| 193 | if ((*mnt)->cgroup2) { |
| 194 | log_err("fio: cgroup weit doesn't work with cgroup2\n"); |
| 195 | goto err; |
| 196 | } |
| 197 | if (write_int_to_file(td, root, "blkio.weight", |
| 198 | td->o.cgroup_weight, |
| 199 | "cgroup open weight")) |
| 200 | goto err; |
| 201 | } |
| 202 | |
| 203 | if (!cgroup_write_pid(td, root, (*mnt)->cgroup2)) { |
| 204 | free(root); |
| 205 | return 0; |
| 206 | } |
| 207 | |
| 208 | err: |
| 209 | free(root); |
| 210 | return 1; |
| 211 | } |
| 212 | |
| 213 | void cgroup_shutdown(struct thread_data *td, struct cgroup_mnt *mnt) |
| 214 | { |
| 215 | if (mnt == NULL) |
| 216 | return; |
| 217 | if (!td->o.cgroup_weight && !td->o.cgroup) |
| 218 | goto out; |
| 219 | |
| 220 | cgroup_del_pid(td, mnt); |
| 221 | out: |
| 222 | if (mnt->path) |
| 223 | sfree(mnt->path); |
| 224 | sfree(mnt); |
| 225 | } |
| 226 | |
| 227 | static void fio_init cgroup_init(void) |
| 228 | { |
| 229 | lock = fio_sem_init(FIO_SEM_UNLOCKED); |
| 230 | if (!lock) |
| 231 | log_err("fio: failed to allocate cgroup lock\n"); |
| 232 | } |
| 233 | |
| 234 | static void fio_exit cgroup_exit(void) |
| 235 | { |
| 236 | fio_sem_remove(lock); |
| 237 | } |