| 1 | /* |
| 2 | * Code related to setting up a blkio cgroup |
| 3 | */ |
| 4 | #include <stdio.h> |
| 5 | #include <stdlib.h> |
| 6 | #include "fio.h" |
| 7 | #include "flist.h" |
| 8 | #include "cgroup.h" |
| 9 | #include "smalloc.h" |
| 10 | |
| 11 | static struct fio_mutex *lock; |
| 12 | |
| 13 | struct cgroup_member { |
| 14 | struct flist_head list; |
| 15 | char *root; |
| 16 | }; |
| 17 | |
| 18 | static void add_cgroup(const char *name, struct flist_head *clist) |
| 19 | { |
| 20 | struct cgroup_member *cm; |
| 21 | |
| 22 | cm = smalloc(sizeof(*cm)); |
| 23 | INIT_FLIST_HEAD(&cm->list); |
| 24 | cm->root = smalloc_strdup(name); |
| 25 | |
| 26 | fio_mutex_down(lock); |
| 27 | flist_add_tail(&cm->list, clist); |
| 28 | fio_mutex_up(lock); |
| 29 | } |
| 30 | |
| 31 | void cgroup_kill(struct flist_head *clist) |
| 32 | { |
| 33 | struct flist_head *n, *tmp; |
| 34 | struct cgroup_member *cm; |
| 35 | |
| 36 | fio_mutex_down(lock); |
| 37 | |
| 38 | flist_for_each_safe(n, tmp, clist) { |
| 39 | cm = flist_entry(n, struct cgroup_member, list); |
| 40 | rmdir(cm->root); |
| 41 | flist_del(&cm->list); |
| 42 | sfree(cm->root); |
| 43 | sfree(cm); |
| 44 | } |
| 45 | |
| 46 | fio_mutex_up(lock); |
| 47 | } |
| 48 | |
| 49 | /* |
| 50 | * Check if the given root appears valid |
| 51 | */ |
| 52 | static int cgroup_check_fs(struct thread_data *td) |
| 53 | { |
| 54 | struct stat sb; |
| 55 | char tmp[256]; |
| 56 | |
| 57 | sprintf(tmp, "%s/tasks", td->o.cgroup_root); |
| 58 | return stat(tmp, &sb); |
| 59 | } |
| 60 | |
| 61 | static char *get_cgroup_root(struct thread_data *td) |
| 62 | { |
| 63 | char *str = malloc(64); |
| 64 | |
| 65 | if (td->o.cgroup) |
| 66 | sprintf(str, "%s/%s", td->o.cgroup_root, td->o.cgroup); |
| 67 | else |
| 68 | sprintf(str, "%s/%s", td->o.cgroup_root, td->o.name); |
| 69 | |
| 70 | return str; |
| 71 | } |
| 72 | |
| 73 | static int cgroup_write_pid(struct thread_data *td, const char *root) |
| 74 | { |
| 75 | char tmp[256]; |
| 76 | FILE *f; |
| 77 | |
| 78 | sprintf(tmp, "%s/tasks", root); |
| 79 | f = fopen(tmp, "w"); |
| 80 | if (!f) { |
| 81 | td_verror(td, errno, "cgroup open tasks"); |
| 82 | return 1; |
| 83 | } |
| 84 | |
| 85 | fprintf(f, "%d", td->pid); |
| 86 | fclose(f); |
| 87 | return 0; |
| 88 | } |
| 89 | |
| 90 | /* |
| 91 | * Add pid to given class |
| 92 | */ |
| 93 | static int cgroup_add_pid(struct thread_data *td) |
| 94 | { |
| 95 | char *root; |
| 96 | int ret; |
| 97 | |
| 98 | root = get_cgroup_root(td); |
| 99 | ret = cgroup_write_pid(td, root); |
| 100 | free(root); |
| 101 | return ret; |
| 102 | } |
| 103 | |
| 104 | /* |
| 105 | * Move pid to root class |
| 106 | */ |
| 107 | static int cgroup_del_pid(struct thread_data *td) |
| 108 | { |
| 109 | return cgroup_write_pid(td, td->o.cgroup_root); |
| 110 | } |
| 111 | |
| 112 | int cgroup_setup(struct thread_data *td, struct flist_head *clist) |
| 113 | { |
| 114 | char *root, tmp[256]; |
| 115 | FILE *f; |
| 116 | |
| 117 | if (cgroup_check_fs(td)) { |
| 118 | log_err("fio: blkio cgroup mount point %s not valid\n", |
| 119 | td->o.cgroup_root); |
| 120 | return 1; |
| 121 | } |
| 122 | |
| 123 | /* |
| 124 | * Create container, if it doesn't exist |
| 125 | */ |
| 126 | root = get_cgroup_root(td); |
| 127 | if (mkdir(root, 0755) < 0) { |
| 128 | int __e = errno; |
| 129 | |
| 130 | if (__e != EEXIST) { |
| 131 | td_verror(td, __e, "cgroup mkdir"); |
| 132 | goto err; |
| 133 | } |
| 134 | } else |
| 135 | add_cgroup(root, clist); |
| 136 | |
| 137 | if (td->o.cgroup_weight) { |
| 138 | sprintf(tmp, "%s/blkio.weight", root); |
| 139 | f = fopen(tmp, "w"); |
| 140 | if (!f) { |
| 141 | td_verror(td, errno, "cgroup open weight"); |
| 142 | goto err; |
| 143 | } |
| 144 | |
| 145 | fprintf(f, "%d", td->o.cgroup_weight); |
| 146 | fclose(f); |
| 147 | } |
| 148 | |
| 149 | free(root); |
| 150 | |
| 151 | if (cgroup_add_pid(td)) |
| 152 | return 1; |
| 153 | |
| 154 | return 0; |
| 155 | err: |
| 156 | free(root); |
| 157 | return 1; |
| 158 | } |
| 159 | |
| 160 | void cgroup_shutdown(struct thread_data *td) |
| 161 | { |
| 162 | if (cgroup_check_fs(td)) |
| 163 | return; |
| 164 | if (!td->o.cgroup_weight && td->o.cgroup) |
| 165 | return; |
| 166 | |
| 167 | cgroup_del_pid(td); |
| 168 | } |
| 169 | |
| 170 | static void fio_init cgroup_init(void) |
| 171 | { |
| 172 | lock = fio_mutex_init(1); |
| 173 | } |
| 174 | |
| 175 | static void fio_exit cgroup_exit(void) |
| 176 | { |
| 177 | fio_mutex_remove(lock); |
| 178 | } |