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 #include <linux/refcount.h> 9 10 /* 11 * A cgroup can be associated with multiple css_sets as different tasks may 12 * belong to different cgroups on different hierarchies. In the other 13 * direction, a css_set is naturally associated with multiple cgroups. 14 * This M:N relationship is represented by the following link structure 15 * which exists for each association and allows traversing the associations 16 * from both sides. 17 */ 18 struct cgrp_cset_link { 19 /* the cgroup and css_set this link associates */ 20 struct cgroup *cgrp; 21 struct css_set *cset; 22 23 /* list of cgrp_cset_links anchored at cgrp->cset_links */ 24 struct list_head cset_link; 25 26 /* list of cgrp_cset_links anchored at css_set->cgrp_links */ 27 struct list_head cgrp_link; 28 }; 29 30 /* used to track tasks and csets during migration */ 31 struct cgroup_taskset { 32 /* the src and dst cset list running through cset->mg_node */ 33 struct list_head src_csets; 34 struct list_head dst_csets; 35 36 /* the subsys currently being processed */ 37 int ssid; 38 39 /* 40 * Fields for cgroup_taskset_*() iteration. 41 * 42 * Before migration is committed, the target migration tasks are on 43 * ->mg_tasks of the csets on ->src_csets. After, on ->mg_tasks of 44 * the csets on ->dst_csets. ->csets point to either ->src_csets 45 * or ->dst_csets depending on whether migration is committed. 46 * 47 * ->cur_csets and ->cur_task point to the current task position 48 * during iteration. 49 */ 50 struct list_head *csets; 51 struct css_set *cur_cset; 52 struct task_struct *cur_task; 53 }; 54 55 /* migration context also tracks preloading */ 56 struct cgroup_mgctx { 57 /* 58 * Preloaded source and destination csets. Used to guarantee 59 * atomic success or failure on actual migration. 60 */ 61 struct list_head preloaded_src_csets; 62 struct list_head preloaded_dst_csets; 63 64 /* tasks and csets to migrate */ 65 struct cgroup_taskset tset; 66 67 /* subsystems affected by migration */ 68 u16 ss_mask; 69 }; 70 71 #define CGROUP_TASKSET_INIT(tset) \ 72 { \ 73 .src_csets = LIST_HEAD_INIT(tset.src_csets), \ 74 .dst_csets = LIST_HEAD_INIT(tset.dst_csets), \ 75 .csets = &tset.src_csets, \ 76 } 77 78 #define CGROUP_MGCTX_INIT(name) \ 79 { \ 80 LIST_HEAD_INIT(name.preloaded_src_csets), \ 81 LIST_HEAD_INIT(name.preloaded_dst_csets), \ 82 CGROUP_TASKSET_INIT(name.tset), \ 83 } 84 85 #define DEFINE_CGROUP_MGCTX(name) \ 86 struct cgroup_mgctx name = CGROUP_MGCTX_INIT(name) 87 88 struct cgroup_sb_opts { 89 u16 subsys_mask; 90 unsigned int flags; 91 char *release_agent; 92 bool cpuset_clone_children; 93 char *name; 94 /* User explicitly requested empty subsystem */ 95 bool none; 96 }; 97 98 extern struct mutex cgroup_mutex; 99 extern spinlock_t css_set_lock; 100 extern struct cgroup_subsys *cgroup_subsys[]; 101 extern struct list_head cgroup_roots; 102 extern struct file_system_type cgroup_fs_type; 103 104 /* iterate across the hierarchies */ 105 #define for_each_root(root) \ 106 list_for_each_entry((root), &cgroup_roots, root_list) 107 108 /** 109 * for_each_subsys - iterate all enabled cgroup subsystems 110 * @ss: the iteration cursor 111 * @ssid: the index of @ss, CGROUP_SUBSYS_COUNT after reaching the end 112 */ 113 #define for_each_subsys(ss, ssid) \ 114 for ((ssid) = 0; (ssid) < CGROUP_SUBSYS_COUNT && \ 115 (((ss) = cgroup_subsys[ssid]) || true); (ssid)++) 116 117 static inline bool cgroup_is_dead(const struct cgroup *cgrp) 118 { 119 return !(cgrp->self.flags & CSS_ONLINE); 120 } 121 122 static inline bool notify_on_release(const struct cgroup *cgrp) 123 { 124 return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags); 125 } 126 127 void put_css_set_locked(struct css_set *cset); 128 129 static inline void put_css_set(struct css_set *cset) 130 { 131 unsigned long flags; 132 133 /* 134 * Ensure that the refcount doesn't hit zero while any readers 135 * can see it. Similar to atomic_dec_and_lock(), but for an 136 * rwlock 137 */ 138 if (refcount_dec_not_one(&cset->refcount)) 139 return; 140 141 spin_lock_irqsave(&css_set_lock, flags); 142 put_css_set_locked(cset); 143 spin_unlock_irqrestore(&css_set_lock, flags); 144 } 145 146 /* 147 * refcounted get/put for css_set objects 148 */ 149 static inline void get_css_set(struct css_set *cset) 150 { 151 refcount_inc(&cset->refcount); 152 } 153 154 bool cgroup_ssid_enabled(int ssid); 155 bool cgroup_on_dfl(const struct cgroup *cgrp); 156 157 struct cgroup_root *cgroup_root_from_kf(struct kernfs_root *kf_root); 158 struct cgroup *task_cgroup_from_root(struct task_struct *task, 159 struct cgroup_root *root); 160 struct cgroup *cgroup_kn_lock_live(struct kernfs_node *kn, bool drain_offline); 161 void cgroup_kn_unlock(struct kernfs_node *kn); 162 int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen, 163 struct cgroup_namespace *ns); 164 165 void cgroup_free_root(struct cgroup_root *root); 166 void init_cgroup_root(struct cgroup_root *root, struct cgroup_sb_opts *opts); 167 int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask, int ref_flags); 168 int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask); 169 struct dentry *cgroup_do_mount(struct file_system_type *fs_type, int flags, 170 struct cgroup_root *root, unsigned long magic, 171 struct cgroup_namespace *ns); 172 173 bool cgroup_may_migrate_to(struct cgroup *dst_cgrp); 174 void cgroup_migrate_finish(struct cgroup_mgctx *mgctx); 175 void cgroup_migrate_add_src(struct css_set *src_cset, struct cgroup *dst_cgrp, 176 struct cgroup_mgctx *mgctx); 177 int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx); 178 int cgroup_migrate(struct task_struct *leader, bool threadgroup, 179 struct cgroup_mgctx *mgctx); 180 181 int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader, 182 bool threadgroup); 183 ssize_t __cgroup_procs_write(struct kernfs_open_file *of, char *buf, 184 size_t nbytes, loff_t off, bool threadgroup); 185 ssize_t cgroup_procs_write(struct kernfs_open_file *of, char *buf, size_t nbytes, 186 loff_t off); 187 188 void cgroup_lock_and_drain_offline(struct cgroup *cgrp); 189 190 int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode); 191 int cgroup_rmdir(struct kernfs_node *kn); 192 int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node, 193 struct kernfs_root *kf_root); 194 195 /* 196 * namespace.c 197 */ 198 extern const struct proc_ns_operations cgroupns_operations; 199 200 /* 201 * cgroup-v1.c 202 */ 203 extern struct cftype cgroup1_base_files[]; 204 extern const struct file_operations proc_cgroupstats_operations; 205 extern struct kernfs_syscall_ops cgroup1_kf_syscall_ops; 206 207 bool cgroup1_ssid_disabled(int ssid); 208 void cgroup1_pidlist_destroy_all(struct cgroup *cgrp); 209 void cgroup1_release_agent(struct work_struct *work); 210 void cgroup1_check_for_release(struct cgroup *cgrp); 211 struct dentry *cgroup1_mount(struct file_system_type *fs_type, int flags, 212 void *data, unsigned long magic, 213 struct cgroup_namespace *ns); 214 215 #endif /* __CGROUP_INTERNAL_H */ 216