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 cgroup_fc2context(struct fs_context * fc)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 struct cgroup_of_peak peak; 86 }; 87 88 /* 89 * A cgroup can be associated with multiple css_sets as different tasks may 90 * belong to different cgroups on different hierarchies. In the other 91 * direction, a css_set is naturally associated with multiple cgroups. 92 * This M:N relationship is represented by the following link structure 93 * which exists for each association and allows traversing the associations 94 * from both sides. 95 */ 96 struct cgrp_cset_link { 97 /* the cgroup and css_set this link associates */ 98 struct cgroup *cgrp; 99 struct css_set *cset; 100 101 /* list of cgrp_cset_links anchored at cgrp->cset_links */ 102 struct list_head cset_link; 103 104 /* list of cgrp_cset_links anchored at css_set->cgrp_links */ 105 struct list_head cgrp_link; 106 }; 107 108 /* used to track tasks and csets during migration */ 109 struct cgroup_taskset { 110 /* the src and dst cset list running through cset->mg_node */ 111 struct list_head src_csets; 112 struct list_head dst_csets; 113 114 /* the number of tasks in the set */ 115 int nr_tasks; 116 117 /* the subsys currently being processed */ 118 int ssid; 119 120 /* 121 * Fields for cgroup_taskset_*() iteration. 122 * 123 * Before migration is committed, the target migration tasks are on 124 * ->mg_tasks of the csets on ->src_csets. After, on ->mg_tasks of 125 * the csets on ->dst_csets. ->csets point to either ->src_csets 126 * or ->dst_csets depending on whether migration is committed. 127 * 128 * ->cur_csets and ->cur_task point to the current task position 129 * during iteration. 130 */ 131 struct list_head *csets; 132 struct css_set *cur_cset; 133 struct task_struct *cur_task; 134 }; 135 136 /* migration context also tracks preloading */ 137 struct cgroup_mgctx { 138 /* 139 * Preloaded source and destination csets. Used to guarantee 140 * atomic success or failure on actual migration. 141 */ 142 struct list_head preloaded_src_csets; 143 struct list_head preloaded_dst_csets; 144 145 /* tasks and csets to migrate */ 146 struct cgroup_taskset tset; 147 148 /* subsystems affected by migration */ 149 u16 ss_mask; 150 }; 151 152 #define CGROUP_TASKSET_INIT(tset) \ 153 { \ 154 .src_csets = LIST_HEAD_INIT(tset.src_csets), \ 155 .dst_csets = LIST_HEAD_INIT(tset.dst_csets), \ 156 .csets = &tset.src_csets, \ 157 } 158 159 #define CGROUP_MGCTX_INIT(name) \ 160 { \ 161 LIST_HEAD_INIT(name.preloaded_src_csets), \ 162 LIST_HEAD_INIT(name.preloaded_dst_csets), \ 163 CGROUP_TASKSET_INIT(name.tset), \ 164 } 165 166 #define DEFINE_CGROUP_MGCTX(name) \ 167 struct cgroup_mgctx name = CGROUP_MGCTX_INIT(name) 168 169 extern struct cgroup_subsys *cgroup_subsys[]; 170 extern struct list_head cgroup_roots; 171 172 /* iterate across the hierarchies */ 173 #define for_each_root(root) \ 174 list_for_each_entry_rcu((root), &cgroup_roots, root_list, \ 175 lockdep_is_held(&cgroup_mutex)) 176 177 /** 178 * for_each_subsys - iterate all enabled cgroup subsystems 179 * @ss: the iteration cursor 180 * @ssid: the index of @ss, CGROUP_SUBSYS_COUNT after reaching the end 181 */ 182 #define for_each_subsys(ss, ssid) \ 183 for ((ssid) = 0; (ssid) < CGROUP_SUBSYS_COUNT && \ 184 (((ss) = cgroup_subsys[ssid]) || true); (ssid)++) 185 cgroup_is_dead(const struct cgroup * cgrp)186 static inline bool cgroup_is_dead(const struct cgroup *cgrp) 187 { 188 return !(cgrp->self.flags & CSS_ONLINE); 189 } 190 notify_on_release(const struct cgroup * cgrp)191 static inline bool notify_on_release(const struct cgroup *cgrp) 192 { 193 return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags); 194 } 195 196 void put_css_set_locked(struct css_set *cset); 197 put_css_set(struct css_set * cset)198 static inline void put_css_set(struct css_set *cset) 199 { 200 unsigned long flags; 201 202 /* 203 * Ensure that the refcount doesn't hit zero while any readers 204 * can see it. Similar to atomic_dec_and_lock(), but for an 205 * rwlock 206 */ 207 if (refcount_dec_not_one(&cset->refcount)) 208 return; 209 210 spin_lock_irqsave(&css_set_lock, flags); 211 put_css_set_locked(cset); 212 spin_unlock_irqrestore(&css_set_lock, flags); 213 } 214 215 /* 216 * refcounted get/put for css_set objects 217 */ get_css_set(struct css_set * cset)218 static inline void get_css_set(struct css_set *cset) 219 { 220 refcount_inc(&cset->refcount); 221 } 222 223 bool cgroup_ssid_enabled(int ssid); 224 bool cgroup_on_dfl(const struct cgroup *cgrp); 225 226 struct cgroup_root *cgroup_root_from_kf(struct kernfs_root *kf_root); 227 struct cgroup *task_cgroup_from_root(struct task_struct *task, 228 struct cgroup_root *root); 229 struct cgroup *cgroup_kn_lock_live(struct kernfs_node *kn, bool drain_offline); 230 void cgroup_kn_unlock(struct kernfs_node *kn); 231 int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen, 232 struct cgroup_namespace *ns); 233 234 void cgroup_favor_dynmods(struct cgroup_root *root, bool favor); 235 void cgroup_free_root(struct cgroup_root *root); 236 void init_cgroup_root(struct cgroup_fs_context *ctx); 237 int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask); 238 int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask); 239 int cgroup_do_get_tree(struct fs_context *fc); 240 241 int cgroup_migrate_vet_dst(struct cgroup *dst_cgrp); 242 void cgroup_migrate_finish(struct cgroup_mgctx *mgctx); 243 void cgroup_migrate_add_src(struct css_set *src_cset, struct cgroup *dst_cgrp, 244 struct cgroup_mgctx *mgctx); 245 int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx); 246 int cgroup_migrate(struct task_struct *leader, bool threadgroup, 247 struct cgroup_mgctx *mgctx); 248 249 int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader, 250 bool threadgroup); 251 void cgroup_attach_lock(bool lock_threadgroup); 252 void cgroup_attach_unlock(bool lock_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