cgroup-internal.h (9069B)
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 13extern spinlock_t trace_cgroup_path_lock; 14extern char trace_cgroup_path[TRACE_CGROUP_PATH_LEN]; 15extern 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 */ 45struct 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 60static 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 67struct cgroup_pidlist; 68 69struct 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 */ 94struct 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 */ 107struct 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 */ 135struct 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 167extern struct mutex cgroup_mutex; 168extern spinlock_t css_set_lock; 169extern struct cgroup_subsys *cgroup_subsys[]; 170extern struct list_head cgroup_roots; 171extern struct file_system_type cgroup_fs_type; 172 173/* iterate across the hierarchies */ 174#define for_each_root(root) \ 175 list_for_each_entry((root), &cgroup_roots, root_list) 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 186static inline bool cgroup_is_dead(const struct cgroup *cgrp) 187{ 188 return !(cgrp->self.flags & CSS_ONLINE); 189} 190 191static inline bool notify_on_release(const struct cgroup *cgrp) 192{ 193 return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags); 194} 195 196void put_css_set_locked(struct css_set *cset); 197 198static 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 */ 218static inline void get_css_set(struct css_set *cset) 219{ 220 refcount_inc(&cset->refcount); 221} 222 223bool cgroup_ssid_enabled(int ssid); 224bool cgroup_on_dfl(const struct cgroup *cgrp); 225bool cgroup_is_thread_root(struct cgroup *cgrp); 226bool cgroup_is_threaded(struct cgroup *cgrp); 227 228struct cgroup_root *cgroup_root_from_kf(struct kernfs_root *kf_root); 229struct cgroup *task_cgroup_from_root(struct task_struct *task, 230 struct cgroup_root *root); 231struct cgroup *cgroup_kn_lock_live(struct kernfs_node *kn, bool drain_offline); 232void cgroup_kn_unlock(struct kernfs_node *kn); 233int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen, 234 struct cgroup_namespace *ns); 235 236void cgroup_free_root(struct cgroup_root *root); 237void init_cgroup_root(struct cgroup_fs_context *ctx); 238int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask); 239int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask); 240int cgroup_do_get_tree(struct fs_context *fc); 241 242int cgroup_migrate_vet_dst(struct cgroup *dst_cgrp); 243void cgroup_migrate_finish(struct cgroup_mgctx *mgctx); 244void cgroup_migrate_add_src(struct css_set *src_cset, struct cgroup *dst_cgrp, 245 struct cgroup_mgctx *mgctx); 246int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx); 247int cgroup_migrate(struct task_struct *leader, bool threadgroup, 248 struct cgroup_mgctx *mgctx); 249 250int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader, 251 bool threadgroup); 252struct task_struct *cgroup_procs_write_start(char *buf, bool threadgroup, 253 bool *locked) 254 __acquires(&cgroup_threadgroup_rwsem); 255void cgroup_procs_write_finish(struct task_struct *task, bool locked) 256 __releases(&cgroup_threadgroup_rwsem); 257 258void cgroup_lock_and_drain_offline(struct cgroup *cgrp); 259 260int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode); 261int cgroup_rmdir(struct kernfs_node *kn); 262int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node, 263 struct kernfs_root *kf_root); 264 265int __cgroup_task_count(const struct cgroup *cgrp); 266int cgroup_task_count(const struct cgroup *cgrp); 267 268/* 269 * rstat.c 270 */ 271int cgroup_rstat_init(struct cgroup *cgrp); 272void cgroup_rstat_exit(struct cgroup *cgrp); 273void cgroup_rstat_boot(void); 274void cgroup_base_stat_cputime_show(struct seq_file *seq); 275 276/* 277 * namespace.c 278 */ 279extern const struct proc_ns_operations cgroupns_operations; 280 281/* 282 * cgroup-v1.c 283 */ 284extern struct cftype cgroup1_base_files[]; 285extern struct kernfs_syscall_ops cgroup1_kf_syscall_ops; 286extern const struct fs_parameter_spec cgroup1_fs_parameters[]; 287 288int proc_cgroupstats_show(struct seq_file *m, void *v); 289bool cgroup1_ssid_disabled(int ssid); 290void cgroup1_pidlist_destroy_all(struct cgroup *cgrp); 291void cgroup1_release_agent(struct work_struct *work); 292void cgroup1_check_for_release(struct cgroup *cgrp); 293int cgroup1_parse_param(struct fs_context *fc, struct fs_parameter *param); 294int cgroup1_get_tree(struct fs_context *fc); 295int cgroup1_reconfigure(struct fs_context *ctx); 296 297#endif /* __CGROUP_INTERNAL_H */