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 <sys/types.h>
9 #include "fio.h"
10 #include "flist.h"
11 #include "cgroup.h"
12 #include "smalloc.h"
13
14 static struct fio_mutex *lock;
15
16 struct cgroup_member {
17 struct flist_head list;
18 char *root;
19 unsigned int cgroup_nodelete;
20 };
21
find_cgroup_mnt(struct thread_data * td)22 static char *find_cgroup_mnt(struct thread_data *td)
23 {
24 char *mntpoint = NULL;
25 struct mntent *mnt, dummy;
26 char buf[256] = {0};
27 FILE *f;
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 }
40
41 if (mnt)
42 mntpoint = smalloc_strdup(mnt->mnt_dir);
43 else
44 log_err("fio: cgroup blkio does not appear to be mounted\n");
45
46 endmntent(f);
47 return mntpoint;
48 }
49
add_cgroup(struct thread_data * td,const char * name,struct flist_head * clist)50 static void add_cgroup(struct thread_data *td, const char *name,
51 struct flist_head *clist)
52 {
53 struct cgroup_member *cm;
54
55 if (!lock)
56 return;
57
58 cm = smalloc(sizeof(*cm));
59 if (!cm) {
60 err:
61 log_err("fio: failed to allocate cgroup member\n");
62 return;
63 }
64
65 INIT_FLIST_HEAD(&cm->list);
66 cm->root = smalloc_strdup(name);
67 if (!cm->root) {
68 sfree(cm);
69 goto err;
70 }
71 if (td->o.cgroup_nodelete)
72 cm->cgroup_nodelete = 1;
73 fio_mutex_down(lock);
74 flist_add_tail(&cm->list, clist);
75 fio_mutex_up(lock);
76 }
77
cgroup_kill(struct flist_head * clist)78 void cgroup_kill(struct flist_head *clist)
79 {
80 struct flist_head *n, *tmp;
81 struct cgroup_member *cm;
82
83 if (!lock)
84 return;
85
86 fio_mutex_down(lock);
87
88 flist_for_each_safe(n, tmp, clist) {
89 cm = flist_entry(n, struct cgroup_member, list);
90 if (!cm->cgroup_nodelete)
91 rmdir(cm->root);
92 flist_del(&cm->list);
93 sfree(cm->root);
94 sfree(cm);
95 }
96
97 fio_mutex_up(lock);
98 }
99
get_cgroup_root(struct thread_data * td,char * mnt)100 static char *get_cgroup_root(struct thread_data *td, char *mnt)
101 {
102 char *str = malloc(64);
103
104 if (td->o.cgroup)
105 sprintf(str, "%s%s%s", mnt, FIO_OS_PATH_SEPARATOR, td->o.cgroup);
106 else
107 sprintf(str, "%s%s%s", mnt, FIO_OS_PATH_SEPARATOR, td->o.name);
108
109 return str;
110 }
111
write_int_to_file(struct thread_data * td,const char * path,const char * filename,unsigned int val,const char * onerr)112 static int write_int_to_file(struct thread_data *td, const char *path,
113 const char *filename, unsigned int val,
114 const char *onerr)
115 {
116 char tmp[256];
117 FILE *f;
118
119 sprintf(tmp, "%s%s%s", path, FIO_OS_PATH_SEPARATOR, filename);
120 f = fopen(tmp, "w");
121 if (!f) {
122 td_verror(td, errno, onerr);
123 return 1;
124 }
125
126 fprintf(f, "%u", val);
127 fclose(f);
128 return 0;
129
130 }
131
cgroup_write_pid(struct thread_data * td,const char * root)132 static int cgroup_write_pid(struct thread_data *td, const char *root)
133 {
134 unsigned int val = td->pid;
135
136 return write_int_to_file(td, root, "tasks", val, "cgroup write pid");
137 }
138
139 /*
140 * Move pid to root class
141 */
cgroup_del_pid(struct thread_data * td,char * mnt)142 static int cgroup_del_pid(struct thread_data *td, char *mnt)
143 {
144 return cgroup_write_pid(td, mnt);
145 }
146
cgroup_setup(struct thread_data * td,struct flist_head * clist,char ** mnt)147 int cgroup_setup(struct thread_data *td, struct flist_head *clist, char **mnt)
148 {
149 char *root;
150
151 if (!*mnt) {
152 *mnt = find_cgroup_mnt(td);
153 if (!*mnt)
154 return 1;
155 }
156
157 /*
158 * Create container, if it doesn't exist
159 */
160 root = get_cgroup_root(td, *mnt);
161 if (mkdir(root, 0755) < 0) {
162 int __e = errno;
163
164 if (__e != EEXIST) {
165 td_verror(td, __e, "cgroup mkdir");
166 log_err("fio: path %s\n", root);
167 goto err;
168 }
169 } else
170 add_cgroup(td, root, clist);
171
172 if (td->o.cgroup_weight) {
173 if (write_int_to_file(td, root, "blkio.weight",
174 td->o.cgroup_weight,
175 "cgroup open weight"))
176 goto err;
177 }
178
179 if (!cgroup_write_pid(td, root)) {
180 free(root);
181 return 0;
182 }
183
184 err:
185 free(root);
186 return 1;
187 }
188
cgroup_shutdown(struct thread_data * td,char ** mnt)189 void cgroup_shutdown(struct thread_data *td, char **mnt)
190 {
191 if (*mnt == NULL)
192 return;
193 if (!td->o.cgroup_weight && !td->o.cgroup)
194 return;
195
196 cgroup_del_pid(td, *mnt);
197 }
198
cgroup_init(void)199 static void fio_init cgroup_init(void)
200 {
201 lock = fio_mutex_init(FIO_MUTEX_UNLOCKED);
202 if (!lock)
203 log_err("fio: failed to allocate cgroup lock\n");
204 }
205
cgroup_exit(void)206 static void fio_exit cgroup_exit(void)
207 {
208 fio_mutex_remove(lock);
209 }
210