1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef __CGROUP_INTERNAL_H 3 #define __CGROUP_INTERNAL_H 4 5 #include <linux/cgroup.h> 6 #include <linux/kernfs.h> 7 #include <linux/workqueue.h> 8 #include <linux/list.h> 9 #include <linux/refcount.h> 10 #include <linux/fs_parser.h> 11 12 #define TRACE_CGROUP_PATH_LEN 1024 13 extern spinlock_t trace_cgroup_path_lock; 14 extern char trace_cgroup_path[TRACE_CGROUP_PATH_LEN]; 15 extern void __init enable_debug_cgroup(void); 16 17 /* 18 * cgroup_path() takes a spin lock. It is good practice not to take 19 * spin locks within trace point handlers, as they are mostly hidden 20 * from normal view. As cgroup_path() can take the kernfs_rename_lock 21 * spin lock, it is best to not call that function from the trace event 22 * handler. 23 * 24 * Note: trace_cgroup_##type##_enabled() is a static branch that will only 25 * be set when the trace event is enabled. 26 */ 27 #define TRACE_CGROUP_PATH(type, cgrp, ...) \ 28 do { \ 29 if (trace_cgroup_##type##_enabled()) { \ 30 unsigned long flags; \ 31 spin_lock_irqsave(&trace_cgroup_path_lock, \ 32 flags); \ 33 cgroup_path(cgrp, trace_cgroup_path, \ 34 TRACE_CGROUP_PATH_LEN); \ 35 trace_cgroup_##type(cgrp, trace_cgroup_path, \ 36 ##__VA_ARGS__); \ 37 spin_unlock_irqrestore(&trace_cgroup_path_lock, \ 38 flags); \ 39 } \ 40 } while (0) 41 42 /* 43 * The cgroup filesystem superblock creation/mount context. 44 */ 45 struct cgroup_fs_context { 46 struct kernfs_fs_context kfc; 47 struct cgroup_root *root; 48 struct cgroup_namespace *ns; 49 unsigned int flags; /* CGRP_ROOT_* flags */ 50 51 /* cgroup1 bits */ 52 bool cpuset_clone_children; 53 bool none; /* User explicitly requested empty subsystem */ 54 bool all_ss; /* Seen 'all' option */ 55 u16 subsys_mask; /* Selected subsystems */ 56 char *name; /* Hierarchy name */ 57 char *release_agent; /* Path for release notifications */ 58 }; 59 60 static inline struct cgroup_fs_context *cgroup_fc2context(struct fs_context *fc) 61 { 62 struct kernfs_fs_context *kfc = fc->fs_private; 63 64 return container_of(kfc, struct cgroup_fs_context, kfc); 65 } 66 67 struct cgroup_pidlist; 68 69 struct cgroup_file_ctx { 70 struct cgroup_namespace *ns; 71 72 struct { 73 void *trigger; 74 } psi; 75 76 struct { 77 bool started; 78 struct css_task_iter iter; 79 } procs; 80 81 struct { 82 struct cgroup_pidlist *pidlist; 83 } procs1; 84 }; 85 86 /* 87 * A cgroup can be associated with multiple css_sets as different tasks may 88 * belong to different cgroups on different hierarchies. In the other 89 * direction, a css_set is naturally associated with multiple cgroups. 90 * This M:N relationship is represented by the following link structure 91 * which exists for each association and allows traversing the associations 92 * from both sides. 93 */ 94 struct cgrp_cset_link { 95 /* the cgroup and css_set this link associates */ 96 struct cgroup *cgrp; 97 struct css_set *cset; 98 99 /* list of cgrp_cset_links anchored at cgrp->cset_links */ 100 struct list_head cset_link; 101 102 /* list of cgrp_cset_links anchored at css_set->cgrp_links */ 103 struct list_head cgrp_link; 104 }; 105 106 /* used to track tasks and csets during migration */ 107 struct cgroup_taskset { 108 /* the src and dst cset list running through cset->mg_node */ 109 struct list_head src_csets; 110 struct list_head dst_csets; 111 112 /* the number of tasks in the set */ 113 int nr_tasks; 114 115 /* the subsys currently being processed */ 116 int ssid; 117 118 /* 119 * Fields for cgroup_taskset_*() iteration. 120 * 121 * Before migration is committed, the target migration tasks are on 122 * ->mg_tasks of the csets on ->src_csets. After, on ->mg_tasks of 123 * the csets on ->dst_csets. ->csets point to either ->src_csets 124 * or ->dst_csets depending on whether migration is committed. 125 * 126 * ->cur_csets and ->cur_task point to the current task position 127 * during iteration. 128 */ 129 struct list_head *csets; 130 struct css_set *cur_cset; 131 struct task_struct *cur_task; 132 }; 133 134 /* migration context also tracks preloading */ 135 struct cgroup_mgctx { 136 /* 137 * Preloaded source and destination csets. Used to guarantee 138 * atomic success or failure on actual migration. 139 */ 140 struct list_head preloaded_src_csets; 141 struct list_head preloaded_dst_csets; 142 143 /* tasks and csets to migrate */ 144 struct cgroup_taskset tset; 145 146 /* subsystems affected by migration */ 147 u16 ss_mask; 148 }; 149 150 #define CGROUP_TASKSET_INIT(tset) \ 151 { \ 152 .src_csets = LIST_HEAD_INIT(tset.src_csets), \ 153 .dst_csets = LIST_HEAD_INIT(tset.dst_csets), \ 154 .csets = &tset.src_csets, \ 155 } 156 157 #define CGROUP_MGCTX_INIT(name) \ 158 { \ 159 LIST_HEAD_INIT(name.preloaded_src_csets), \ 160 LIST_HEAD_INIT(name.preloaded_dst_csets), \ 161 CGROUP_TASKSET_INIT(name.tset), \ 162 } 163 164 #define DEFINE_CGROUP_MGCTX(name) \ 165 struct cgroup_mgctx name = CGROUP_MGCTX_INIT(name) 166 167 extern spinlock_t css_set_lock; 168 extern struct cgroup_subsys *cgroup_subsys[]; 169 extern struct list_head cgroup_roots; 170 extern struct file_system_type cgroup_fs_type; 171 172 /* iterate across the hierarchies */ 173 #define for_each_root(root) \ 174 list_for_each_entry((root), &cgroup_roots, root_list) 175 176 /** 177 * for_each_subsys - iterate all enabled cgroup subsystems 178 * @ss: the iteration cursor 179 * @ssid: the index of @ss, CGROUP_SUBSYS_COUNT after reaching the end 180 */ 181 #define for_each_subsys(ss, ssid) \ 182 for ((ssid) = 0; (ssid) < CGROUP_SUBSYS_COUNT && \ 183 (((ss) = cgroup_subsys[ssid]) || true); (ssid)++) 184 185 static inline bool cgroup_is_dead(const struct cgroup *cgrp) 186 { 187 return !(cgrp->self.flags & CSS_ONLINE); 188 } 189 190 static inline bool notify_on_release(const struct cgroup *cgrp) 191 { 192 return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags); 193 } 194 195 void put_css_set_locked(struct css_set *cset); 196 197 static inline void put_css_set(struct css_set *cset) 198 { 199 unsigned long flags; 200 201 /* 202 * Ensure that the refcount doesn't hit zero while any readers 203 * can see it. Similar to atomic_dec_and_lock(), but for an 204 * rwlock 205 */ 206 if (refcount_dec_not_one(&cset->refcount)) 207 return; 208 209 spin_lock_irqsave(&css_set_lock, flags); 210 put_css_set_locked(cset); 211 spin_unlock_irqrestore(&css_set_lock, flags); 212 } 213 214 /* 215 * refcounted get/put for css_set objects 216 */ 217 static inline void get_css_set(struct css_set *cset) 218 { 219 refcount_inc(&cset->refcount); 220 } 221 222 bool cgroup_ssid_enabled(int ssid); 223 bool cgroup_on_dfl(const struct cgroup *cgrp); 224 bool cgroup_is_thread_root(struct cgroup *cgrp); 225 bool cgroup_is_threaded(struct cgroup *cgrp); 226 227 struct cgroup_root *cgroup_root_from_kf(struct kernfs_root *kf_root); 228 struct cgroup *task_cgroup_from_root(struct task_struct *task, 229 struct cgroup_root *root); 230 struct cgroup *cgroup_kn_lock_live(struct kernfs_node *kn, bool drain_offline); 231 void cgroup_kn_unlock(struct kernfs_node *kn); 232 int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen, 233 struct cgroup_namespace *ns); 234 235 void cgroup_favor_dynmods(struct cgroup_root *root, bool favor); 236 void cgroup_free_root(struct cgroup_root *root); 237 void init_cgroup_root(struct cgroup_fs_context *ctx); 238 int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask); 239 int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask); 240 int cgroup_do_get_tree(struct fs_context *fc); 241 242 int cgroup_migrate_vet_dst(struct cgroup *dst_cgrp); 243 void cgroup_migrate_finish(struct cgroup_mgctx *mgctx); 244 void cgroup_migrate_add_src(struct css_set *src_cset, struct cgroup *dst_cgrp, 245 struct cgroup_mgctx *mgctx); 246 int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx); 247 int cgroup_migrate(struct task_struct *leader, bool threadgroup, 248 struct cgroup_mgctx *mgctx); 249 250 int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader, 251 bool threadgroup); 252 void cgroup_attach_lock(bool lock_threadgroup); 253 void cgroup_attach_unlock(bool lock_threadgroup); 254 struct task_struct *cgroup_procs_write_start(char *buf, bool threadgroup, 255 bool *locked) 256 __acquires(&cgroup_threadgroup_rwsem); 257 void cgroup_procs_write_finish(struct task_struct *task, bool locked) 258 __releases(&cgroup_threadgroup_rwsem); 259 260 void cgroup_lock_and_drain_offline(struct cgroup *cgrp); 261 262 int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode); 263 int cgroup_rmdir(struct kernfs_node *kn); 264 int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node, 265 struct kernfs_root *kf_root); 266 267 int __cgroup_task_count(const struct cgroup *cgrp); 268 int cgroup_task_count(const struct cgroup *cgrp); 269 270 /* 271 * rstat.c 272 */ 273 int cgroup_rstat_init(struct cgroup *cgrp); 274 void cgroup_rstat_exit(struct cgroup *cgrp); 275 void cgroup_rstat_boot(void); 276 void cgroup_base_stat_cputime_show(struct seq_file *seq); 277 278 /* 279 * namespace.c 280 */ 281 extern const struct proc_ns_operations cgroupns_operations; 282 283 /* 284 * cgroup-v1.c 285 */ 286 extern struct cftype cgroup1_base_files[]; 287 extern struct kernfs_syscall_ops cgroup1_kf_syscall_ops; 288 extern const struct fs_parameter_spec cgroup1_fs_parameters[]; 289 290 int proc_cgroupstats_show(struct seq_file *m, void *v); 291 bool cgroup1_ssid_disabled(int ssid); 292 void cgroup1_pidlist_destroy_all(struct cgroup *cgrp); 293 void cgroup1_release_agent(struct work_struct *work); 294 void cgroup1_check_for_release(struct cgroup *cgrp); 295 int cgroup1_parse_param(struct fs_context *fc, struct fs_parameter *param); 296 int cgroup1_get_tree(struct fs_context *fc); 297 int cgroup1_reconfigure(struct fs_context *ctx); 298 299 #endif /* __CGROUP_INTERNAL_H */ 300