1 #ifndef __CGROUP_INTERNAL_H 2 #define __CGROUP_INTERNAL_H 3 4 #include <linux/cgroup.h> 5 #include <linux/kernfs.h> 6 #include <linux/workqueue.h> 7 #include <linux/list.h> 8 9 /* 10 * A cgroup can be associated with multiple css_sets as different tasks may 11 * belong to different cgroups on different hierarchies. In the other 12 * direction, a css_set is naturally associated with multiple cgroups. 13 * This M:N relationship is represented by the following link structure 14 * which exists for each association and allows traversing the associations 15 * from both sides. 16 */ 17 struct cgrp_cset_link { 18 /* the cgroup and css_set this link associates */ 19 struct cgroup *cgrp; 20 struct css_set *cset; 21 22 /* list of cgrp_cset_links anchored at cgrp->cset_links */ 23 struct list_head cset_link; 24 25 /* list of cgrp_cset_links anchored at css_set->cgrp_links */ 26 struct list_head cgrp_link; 27 }; 28 29 /* used to track tasks and csets during migration */ 30 struct cgroup_taskset { 31 /* the src and dst cset list running through cset->mg_node */ 32 struct list_head src_csets; 33 struct list_head dst_csets; 34 35 /* the subsys currently being processed */ 36 int ssid; 37 38 /* 39 * Fields for cgroup_taskset_*() iteration. 40 * 41 * Before migration is committed, the target migration tasks are on 42 * ->mg_tasks of the csets on ->src_csets. After, on ->mg_tasks of 43 * the csets on ->dst_csets. ->csets point to either ->src_csets 44 * or ->dst_csets depending on whether migration is committed. 45 * 46 * ->cur_csets and ->cur_task point to the current task position 47 * during iteration. 48 */ 49 struct list_head *csets; 50 struct css_set *cur_cset; 51 struct task_struct *cur_task; 52 }; 53 54 /* migration context also tracks preloading */ 55 struct cgroup_mgctx { 56 /* 57 * Preloaded source and destination csets. Used to guarantee 58 * atomic success or failure on actual migration. 59 */ 60 struct list_head preloaded_src_csets; 61 struct list_head preloaded_dst_csets; 62 63 /* tasks and csets to migrate */ 64 struct cgroup_taskset tset; 65 66 /* subsystems affected by migration */ 67 u16 ss_mask; 68 }; 69 70 #define CGROUP_TASKSET_INIT(tset) \ 71 { \ 72 .src_csets = LIST_HEAD_INIT(tset.src_csets), \ 73 .dst_csets = LIST_HEAD_INIT(tset.dst_csets), \ 74 .csets = &tset.src_csets, \ 75 } 76 77 #define CGROUP_MGCTX_INIT(name) \ 78 { \ 79 LIST_HEAD_INIT(name.preloaded_src_csets), \ 80 LIST_HEAD_INIT(name.preloaded_dst_csets), \ 81 CGROUP_TASKSET_INIT(name.tset), \ 82 } 83 84 #define DEFINE_CGROUP_MGCTX(name) \ 85 struct cgroup_mgctx name = CGROUP_MGCTX_INIT(name) 86 87 struct cgroup_sb_opts { 88 u16 subsys_mask; 89 unsigned int flags; 90 char *release_agent; 91 bool cpuset_clone_children; 92 char *name; 93 /* User explicitly requested empty subsystem */ 94 bool none; 95 }; 96 97 extern struct mutex cgroup_mutex; 98 extern spinlock_t css_set_lock; 99 extern struct cgroup_subsys *cgroup_subsys[]; 100 extern struct list_head cgroup_roots; 101 extern struct file_system_type cgroup_fs_type; 102 103 /* iterate across the hierarchies */ 104 #define for_each_root(root) \ 105 list_for_each_entry((root), &cgroup_roots, root_list) 106 107 /** 108 * for_each_subsys - iterate all enabled cgroup subsystems 109 * @ss: the iteration cursor 110 * @ssid: the index of @ss, CGROUP_SUBSYS_COUNT after reaching the end 111 */ 112 #define for_each_subsys(ss, ssid) \ 113 for ((ssid) = 0; (ssid) < CGROUP_SUBSYS_COUNT && \ 114 (((ss) = cgroup_subsys[ssid]) || true); (ssid)++) 115 116 static inline bool cgroup_is_dead(const struct cgroup *cgrp) 117 { 118 return !(cgrp->self.flags & CSS_ONLINE); 119 } 120 121 static inline bool notify_on_release(const struct cgroup *cgrp) 122 { 123 return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags); 124 } 125 126 void put_css_set_locked(struct css_set *cset); 127 128 static inline void put_css_set(struct css_set *cset) 129 { 130 unsigned long flags; 131 132 /* 133 * Ensure that the refcount doesn't hit zero while any readers 134 * can see it. Similar to atomic_dec_and_lock(), but for an 135 * rwlock 136 */ 137 if (atomic_add_unless(&cset->refcount, -1, 1)) 138 return; 139 140 spin_lock_irqsave(&css_set_lock, flags); 141 put_css_set_locked(cset); 142 spin_unlock_irqrestore(&css_set_lock, flags); 143 } 144 145 /* 146 * refcounted get/put for css_set objects 147 */ 148 static inline void get_css_set(struct css_set *cset) 149 { 150 atomic_inc(&cset->refcount); 151 } 152 153 bool cgroup_ssid_enabled(int ssid); 154 bool cgroup_on_dfl(const struct cgroup *cgrp); 155 156 struct cgroup_root *cgroup_root_from_kf(struct kernfs_root *kf_root); 157 struct cgroup *task_cgroup_from_root(struct task_struct *task, 158 struct cgroup_root *root); 159 struct cgroup *cgroup_kn_lock_live(struct kernfs_node *kn, bool drain_offline); 160 void cgroup_kn_unlock(struct kernfs_node *kn); 161 int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen, 162 struct cgroup_namespace *ns); 163 164 void cgroup_free_root(struct cgroup_root *root); 165 void init_cgroup_root(struct cgroup_root *root, struct cgroup_sb_opts *opts); 166 int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask); 167 int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask); 168 struct dentry *cgroup_do_mount(struct file_system_type *fs_type, int flags, 169 struct cgroup_root *root, unsigned long magic, 170 struct cgroup_namespace *ns); 171 172 bool cgroup_may_migrate_to(struct cgroup *dst_cgrp); 173 void cgroup_migrate_finish(struct cgroup_mgctx *mgctx); 174 void cgroup_migrate_add_src(struct css_set *src_cset, struct cgroup *dst_cgrp, 175 struct cgroup_mgctx *mgctx); 176 int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx); 177 int cgroup_migrate(struct task_struct *leader, bool threadgroup, 178 struct cgroup_mgctx *mgctx); 179 180 int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader, 181 bool threadgroup); 182 ssize_t __cgroup_procs_write(struct kernfs_open_file *of, char *buf, 183 size_t nbytes, loff_t off, bool threadgroup); 184 ssize_t cgroup_procs_write(struct kernfs_open_file *of, char *buf, size_t nbytes, 185 loff_t off); 186 187 void cgroup_lock_and_drain_offline(struct cgroup *cgrp); 188 189 int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode); 190 int cgroup_rmdir(struct kernfs_node *kn); 191 int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node, 192 struct kernfs_root *kf_root); 193 194 /* 195 * namespace.c 196 */ 197 extern const struct proc_ns_operations cgroupns_operations; 198 199 /* 200 * cgroup-v1.c 201 */ 202 extern struct cftype cgroup1_base_files[]; 203 extern const struct file_operations proc_cgroupstats_operations; 204 extern struct kernfs_syscall_ops cgroup1_kf_syscall_ops; 205 206 bool cgroup1_ssid_disabled(int ssid); 207 void cgroup1_pidlist_destroy_all(struct cgroup *cgrp); 208 void cgroup1_release_agent(struct work_struct *work); 209 void cgroup1_check_for_release(struct cgroup *cgrp); 210 struct dentry *cgroup1_mount(struct file_system_type *fs_type, int flags, 211 void *data, unsigned long magic, 212 struct cgroup_namespace *ns); 213 214 #endif /* __CGROUP_INTERNAL_H */ 215