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 11 #define TRACE_CGROUP_PATH_LEN 1024 12 extern spinlock_t trace_cgroup_path_lock; 13 extern char trace_cgroup_path[TRACE_CGROUP_PATH_LEN]; 14 extern bool cgroup_debug; 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 spin_lock(&trace_cgroup_path_lock); \ 31 cgroup_path(cgrp, trace_cgroup_path, \ 32 TRACE_CGROUP_PATH_LEN); \ 33 trace_cgroup_##type(cgrp, trace_cgroup_path, \ 34 ##__VA_ARGS__); \ 35 spin_unlock(&trace_cgroup_path_lock); \ 36 } \ 37 } while (0) 38 39 /* 40 * A cgroup can be associated with multiple css_sets as different tasks may 41 * belong to different cgroups on different hierarchies. In the other 42 * direction, a css_set is naturally associated with multiple cgroups. 43 * This M:N relationship is represented by the following link structure 44 * which exists for each association and allows traversing the associations 45 * from both sides. 46 */ 47 struct cgrp_cset_link { 48 /* the cgroup and css_set this link associates */ 49 struct cgroup *cgrp; 50 struct css_set *cset; 51 52 /* list of cgrp_cset_links anchored at cgrp->cset_links */ 53 struct list_head cset_link; 54 55 /* list of cgrp_cset_links anchored at css_set->cgrp_links */ 56 struct list_head cgrp_link; 57 }; 58 59 /* used to track tasks and csets during migration */ 60 struct cgroup_taskset { 61 /* the src and dst cset list running through cset->mg_node */ 62 struct list_head src_csets; 63 struct list_head dst_csets; 64 65 /* the number of tasks in the set */ 66 int nr_tasks; 67 68 /* the subsys currently being processed */ 69 int ssid; 70 71 /* 72 * Fields for cgroup_taskset_*() iteration. 73 * 74 * Before migration is committed, the target migration tasks are on 75 * ->mg_tasks of the csets on ->src_csets. After, on ->mg_tasks of 76 * the csets on ->dst_csets. ->csets point to either ->src_csets 77 * or ->dst_csets depending on whether migration is committed. 78 * 79 * ->cur_csets and ->cur_task point to the current task position 80 * during iteration. 81 */ 82 struct list_head *csets; 83 struct css_set *cur_cset; 84 struct task_struct *cur_task; 85 }; 86 87 /* migration context also tracks preloading */ 88 struct cgroup_mgctx { 89 /* 90 * Preloaded source and destination csets. Used to guarantee 91 * atomic success or failure on actual migration. 92 */ 93 struct list_head preloaded_src_csets; 94 struct list_head preloaded_dst_csets; 95 96 /* tasks and csets to migrate */ 97 struct cgroup_taskset tset; 98 99 /* subsystems affected by migration */ 100 u16 ss_mask; 101 }; 102 103 #define CGROUP_TASKSET_INIT(tset) \ 104 { \ 105 .src_csets = LIST_HEAD_INIT(tset.src_csets), \ 106 .dst_csets = LIST_HEAD_INIT(tset.dst_csets), \ 107 .csets = &tset.src_csets, \ 108 } 109 110 #define CGROUP_MGCTX_INIT(name) \ 111 { \ 112 LIST_HEAD_INIT(name.preloaded_src_csets), \ 113 LIST_HEAD_INIT(name.preloaded_dst_csets), \ 114 CGROUP_TASKSET_INIT(name.tset), \ 115 } 116 117 #define DEFINE_CGROUP_MGCTX(name) \ 118 struct cgroup_mgctx name = CGROUP_MGCTX_INIT(name) 119 120 struct cgroup_sb_opts { 121 u16 subsys_mask; 122 unsigned int flags; 123 char *release_agent; 124 bool cpuset_clone_children; 125 char *name; 126 /* User explicitly requested empty subsystem */ 127 bool none; 128 }; 129 130 extern struct mutex cgroup_mutex; 131 extern spinlock_t css_set_lock; 132 extern struct cgroup_subsys *cgroup_subsys[]; 133 extern struct list_head cgroup_roots; 134 extern struct file_system_type cgroup_fs_type; 135 136 /* iterate across the hierarchies */ 137 #define for_each_root(root) \ 138 list_for_each_entry((root), &cgroup_roots, root_list) 139 140 /** 141 * for_each_subsys - iterate all enabled cgroup subsystems 142 * @ss: the iteration cursor 143 * @ssid: the index of @ss, CGROUP_SUBSYS_COUNT after reaching the end 144 */ 145 #define for_each_subsys(ss, ssid) \ 146 for ((ssid) = 0; (ssid) < CGROUP_SUBSYS_COUNT && \ 147 (((ss) = cgroup_subsys[ssid]) || true); (ssid)++) 148 149 static inline bool cgroup_is_dead(const struct cgroup *cgrp) 150 { 151 return !(cgrp->self.flags & CSS_ONLINE); 152 } 153 154 static inline bool notify_on_release(const struct cgroup *cgrp) 155 { 156 return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags); 157 } 158 159 void put_css_set_locked(struct css_set *cset); 160 161 static inline void put_css_set(struct css_set *cset) 162 { 163 unsigned long flags; 164 165 /* 166 * Ensure that the refcount doesn't hit zero while any readers 167 * can see it. Similar to atomic_dec_and_lock(), but for an 168 * rwlock 169 */ 170 if (refcount_dec_not_one(&cset->refcount)) 171 return; 172 173 spin_lock_irqsave(&css_set_lock, flags); 174 put_css_set_locked(cset); 175 spin_unlock_irqrestore(&css_set_lock, flags); 176 } 177 178 /* 179 * refcounted get/put for css_set objects 180 */ 181 static inline void get_css_set(struct css_set *cset) 182 { 183 refcount_inc(&cset->refcount); 184 } 185 186 bool cgroup_ssid_enabled(int ssid); 187 bool cgroup_on_dfl(const struct cgroup *cgrp); 188 bool cgroup_is_thread_root(struct cgroup *cgrp); 189 bool cgroup_is_threaded(struct cgroup *cgrp); 190 191 struct cgroup_root *cgroup_root_from_kf(struct kernfs_root *kf_root); 192 struct cgroup *task_cgroup_from_root(struct task_struct *task, 193 struct cgroup_root *root); 194 struct cgroup *cgroup_kn_lock_live(struct kernfs_node *kn, bool drain_offline); 195 void cgroup_kn_unlock(struct kernfs_node *kn); 196 int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen, 197 struct cgroup_namespace *ns); 198 199 void cgroup_free_root(struct cgroup_root *root); 200 void init_cgroup_root(struct cgroup_root *root, struct cgroup_sb_opts *opts); 201 int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask, int ref_flags); 202 int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask); 203 struct dentry *cgroup_do_mount(struct file_system_type *fs_type, int flags, 204 struct cgroup_root *root, unsigned long magic, 205 struct cgroup_namespace *ns); 206 207 int cgroup_migrate_vet_dst(struct cgroup *dst_cgrp); 208 void cgroup_migrate_finish(struct cgroup_mgctx *mgctx); 209 void cgroup_migrate_add_src(struct css_set *src_cset, struct cgroup *dst_cgrp, 210 struct cgroup_mgctx *mgctx); 211 int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx); 212 int cgroup_migrate(struct task_struct *leader, bool threadgroup, 213 struct cgroup_mgctx *mgctx); 214 215 int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader, 216 bool threadgroup); 217 struct task_struct *cgroup_procs_write_start(char *buf, bool threadgroup) 218 __acquires(&cgroup_threadgroup_rwsem); 219 void cgroup_procs_write_finish(struct task_struct *task) 220 __releases(&cgroup_threadgroup_rwsem); 221 222 void cgroup_lock_and_drain_offline(struct cgroup *cgrp); 223 224 int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode); 225 int cgroup_rmdir(struct kernfs_node *kn); 226 int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node, 227 struct kernfs_root *kf_root); 228 229 int cgroup_task_count(const struct cgroup *cgrp); 230 231 /* 232 * rstat.c 233 */ 234 int cgroup_rstat_init(struct cgroup *cgrp); 235 void cgroup_rstat_exit(struct cgroup *cgrp); 236 void cgroup_rstat_boot(void); 237 void cgroup_base_stat_cputime_show(struct seq_file *seq); 238 239 /* 240 * namespace.c 241 */ 242 extern const struct proc_ns_operations cgroupns_operations; 243 244 /* 245 * cgroup-v1.c 246 */ 247 extern struct cftype cgroup1_base_files[]; 248 extern struct kernfs_syscall_ops cgroup1_kf_syscall_ops; 249 250 int proc_cgroupstats_show(struct seq_file *m, void *v); 251 bool cgroup1_ssid_disabled(int ssid); 252 void cgroup1_pidlist_destroy_all(struct cgroup *cgrp); 253 void cgroup1_release_agent(struct work_struct *work); 254 void cgroup1_check_for_release(struct cgroup *cgrp); 255 struct dentry *cgroup1_mount(struct file_system_type *fs_type, int flags, 256 void *data, unsigned long magic, 257 struct cgroup_namespace *ns); 258 259 #endif /* __CGROUP_INTERNAL_H */ 260