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