1 #ifndef _LINUX_CGROUP_H
2 #define _LINUX_CGROUP_H
6 * Copyright (C) 2003 BULL SA
7 * Copyright (C) 2004-2006 Silicon Graphics, Inc.
11 #include <linux/sched.h>
12 #include <linux/kref.h>
13 #include <linux/cpumask.h>
14 #include <linux/nodemask.h>
15 #include <linux/rcupdate.h>
23 extern int cgroup_init_early(void);
24 extern int cgroup_init(void);
25 extern void cgroup_init_smp(void);
26 extern void cgroup_lock(void);
27 extern void cgroup_unlock(void);
28 extern void cgroup_fork(struct task_struct *p);
29 extern void cgroup_fork_callbacks(struct task_struct *p);
30 extern void cgroup_exit(struct task_struct *p, int run_callbacks);
32 /* Per-subsystem/per-cgroup state maintained by the system. */
33 struct cgroup_subsys_state {
34 /* The cgroup that this subsystem is attached to. Useful
35 * for subsystems that want to know about the cgroup
36 * hierarchy structure */
37 struct cgroup *cgroup;
39 /* State maintained by the cgroup system to allow
40 * subsystems to be "busy". Should be accessed via css_get()
48 /* bits in struct cgroup_subsys_state flags field */
50 CSS_ROOT, /* This CSS is the root of the subsystem */
54 * Call css_get() to hold a reference on the cgroup;
58 static inline void css_get(struct cgroup_subsys_state *css)
60 /* We don't need to reference count the root state */
61 if (!test_bit(CSS_ROOT, &css->flags))
62 atomic_inc(&css->refcnt);
65 * css_put() should be called to release a reference taken by
69 static inline void css_put(struct cgroup_subsys_state *css)
71 if (!test_bit(CSS_ROOT, &css->flags))
72 atomic_dec(&css->refcnt);
76 unsigned long flags; /* "unsigned long" so bitops work */
78 /* count users of this cgroup. >0 means busy, but doesn't
79 * necessarily indicate the number of tasks in the
84 * We link our 'sibling' struct into our parent's 'children'.
85 * Our children link their 'sibling' into our 'children'.
87 struct list_head sibling; /* my parent's children */
88 struct list_head children; /* my children */
90 struct cgroup *parent; /* my parent */
91 struct dentry *dentry; /* cgroup fs entry */
93 /* Private pointers for each registered subsystem */
94 struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT];
96 struct cgroupfs_root *root;
97 struct cgroup *top_cgroup;
102 * The files in the cgroup filesystem mostly have a very simple read/write
103 * handling, some common function will take care of it. Nevertheless some cases
104 * (read tasks) are special and therefore I define this structure for every
108 * When reading/writing to a file:
109 * - the cgroup to use in file->f_dentry->d_parent->d_fsdata
110 * - the 'cftype' of the file is file->f_dentry->d_fsdata
113 #define MAX_CFTYPE_NAME 64
115 /* By convention, the name should begin with the name of the
116 * subsystem, followed by a period */
117 char name[MAX_CFTYPE_NAME];
119 int (*open) (struct inode *inode, struct file *file);
120 ssize_t (*read) (struct cgroup *cont, struct cftype *cft,
122 char __user *buf, size_t nbytes, loff_t *ppos);
124 * read_uint() is a shortcut for the common case of returning a
125 * single integer. Use it in place of read()
127 u64 (*read_uint) (struct cgroup *cont, struct cftype *cft);
128 ssize_t (*write) (struct cgroup *cont, struct cftype *cft,
130 const char __user *buf, size_t nbytes, loff_t *ppos);
133 * write_uint() is a shortcut for the common case of accepting
134 * a single integer (as parsed by simple_strtoull) from
135 * userspace. Use in place of write(); return 0 or error.
137 int (*write_uint) (struct cgroup *cont, struct cftype *cft, u64 val);
139 int (*release) (struct inode *inode, struct file *file);
142 /* Add a new file to the given cgroup directory. Should only be
143 * called by subsystems from within a populate() method */
144 int cgroup_add_file(struct cgroup *cont, struct cgroup_subsys *subsys,
145 const struct cftype *cft);
147 /* Add a set of new files to the given cgroup directory. Should
148 * only be called by subsystems from within a populate() method */
149 int cgroup_add_files(struct cgroup *cont,
150 struct cgroup_subsys *subsys,
151 const struct cftype cft[],
154 int cgroup_is_removed(const struct cgroup *cont);
156 int cgroup_path(const struct cgroup *cont, char *buf, int buflen);
158 int __cgroup_task_count(const struct cgroup *cont);
159 static inline int cgroup_task_count(const struct cgroup *cont)
163 task_count = __cgroup_task_count(cont);
168 /* Return true if the cgroup is a descendant of the current cgroup */
169 int cgroup_is_descendant(const struct cgroup *cont);
171 /* Control Group subsystem type. See Documentation/cgroups.txt for details */
173 struct cgroup_subsys {
174 struct cgroup_subsys_state *(*create)(struct cgroup_subsys *ss,
175 struct cgroup *cont);
176 void (*destroy)(struct cgroup_subsys *ss, struct cgroup *cont);
177 int (*can_attach)(struct cgroup_subsys *ss,
178 struct cgroup *cont, struct task_struct *tsk);
179 void (*attach)(struct cgroup_subsys *ss, struct cgroup *cont,
180 struct cgroup *old_cont, struct task_struct *tsk);
181 void (*fork)(struct cgroup_subsys *ss, struct task_struct *task);
182 void (*exit)(struct cgroup_subsys *ss, struct task_struct *task);
183 int (*populate)(struct cgroup_subsys *ss,
184 struct cgroup *cont);
185 void (*bind)(struct cgroup_subsys *ss, struct cgroup *root);
189 #define MAX_CGROUP_TYPE_NAMELEN 32
192 /* Protected by RCU */
193 struct cgroupfs_root *root;
195 struct list_head sibling;
200 #define SUBSYS(_x) extern struct cgroup_subsys _x ## _subsys;
201 #include <linux/cgroup_subsys.h>
204 static inline struct cgroup_subsys_state *cgroup_subsys_state(
205 struct cgroup *cont, int subsys_id)
207 return cont->subsys[subsys_id];
210 static inline struct cgroup_subsys_state *task_subsys_state(
211 struct task_struct *task, int subsys_id)
213 return rcu_dereference(task->cgroups.subsys[subsys_id]);
216 static inline struct cgroup* task_cgroup(struct task_struct *task,
219 return task_subsys_state(task, subsys_id)->cgroup;
222 int cgroup_path(const struct cgroup *cont, char *buf, int buflen);
224 #else /* !CONFIG_CGROUPS */
226 static inline int cgroup_init_early(void) { return 0; }
227 static inline int cgroup_init(void) { return 0; }
228 static inline void cgroup_init_smp(void) {}
229 static inline void cgroup_fork(struct task_struct *p) {}
230 static inline void cgroup_fork_callbacks(struct task_struct *p) {}
231 static inline void cgroup_exit(struct task_struct *p, int callbacks) {}
233 static inline void cgroup_lock(void) {}
234 static inline void cgroup_unlock(void) {}
236 #endif /* !CONFIG_CGROUPS */
238 #endif /* _LINUX_CGROUP_H */