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);
29 /* Per-subsystem/per-cgroup state maintained by the system. */
30 struct cgroup_subsys_state {
31 /* The cgroup that this subsystem is attached to. Useful
32 * for subsystems that want to know about the cgroup
33 * hierarchy structure */
34 struct cgroup *cgroup;
36 /* State maintained by the cgroup system to allow
37 * subsystems to be "busy". Should be accessed via css_get()
45 /* bits in struct cgroup_subsys_state flags field */
47 CSS_ROOT, /* This CSS is the root of the subsystem */
51 * Call css_get() to hold a reference on the cgroup;
55 static inline void css_get(struct cgroup_subsys_state *css)
57 /* We don't need to reference count the root state */
58 if (!test_bit(CSS_ROOT, &css->flags))
59 atomic_inc(&css->refcnt);
62 * css_put() should be called to release a reference taken by
66 static inline void css_put(struct cgroup_subsys_state *css)
68 if (!test_bit(CSS_ROOT, &css->flags))
69 atomic_dec(&css->refcnt);
73 unsigned long flags; /* "unsigned long" so bitops work */
75 /* count users of this cgroup. >0 means busy, but doesn't
76 * necessarily indicate the number of tasks in the
81 * We link our 'sibling' struct into our parent's 'children'.
82 * Our children link their 'sibling' into our 'children'.
84 struct list_head sibling; /* my parent's children */
85 struct list_head children; /* my children */
87 struct cgroup *parent; /* my parent */
88 struct dentry *dentry; /* cgroup fs entry */
90 /* Private pointers for each registered subsystem */
91 struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT];
93 struct cgroupfs_root *root;
94 struct cgroup *top_cgroup;
99 * The files in the cgroup filesystem mostly have a very simple read/write
100 * handling, some common function will take care of it. Nevertheless some cases
101 * (read tasks) are special and therefore I define this structure for every
105 * When reading/writing to a file:
106 * - the cgroup to use in file->f_dentry->d_parent->d_fsdata
107 * - the 'cftype' of the file is file->f_dentry->d_fsdata
110 #define MAX_CFTYPE_NAME 64
112 /* By convention, the name should begin with the name of the
113 * subsystem, followed by a period */
114 char name[MAX_CFTYPE_NAME];
116 int (*open) (struct inode *inode, struct file *file);
117 ssize_t (*read) (struct cgroup *cont, struct cftype *cft,
119 char __user *buf, size_t nbytes, loff_t *ppos);
121 * read_uint() is a shortcut for the common case of returning a
122 * single integer. Use it in place of read()
124 u64 (*read_uint) (struct cgroup *cont, struct cftype *cft);
125 ssize_t (*write) (struct cgroup *cont, struct cftype *cft,
127 const char __user *buf, size_t nbytes, loff_t *ppos);
128 int (*release) (struct inode *inode, struct file *file);
131 /* Add a new file to the given cgroup directory. Should only be
132 * called by subsystems from within a populate() method */
133 int cgroup_add_file(struct cgroup *cont, struct cgroup_subsys *subsys,
134 const struct cftype *cft);
136 /* Add a set of new files to the given cgroup directory. Should
137 * only be called by subsystems from within a populate() method */
138 int cgroup_add_files(struct cgroup *cont,
139 struct cgroup_subsys *subsys,
140 const struct cftype cft[],
143 int cgroup_is_removed(const struct cgroup *cont);
145 int cgroup_path(const struct cgroup *cont, char *buf, int buflen);
147 int __cgroup_task_count(const struct cgroup *cont);
148 static inline int cgroup_task_count(const struct cgroup *cont)
152 task_count = __cgroup_task_count(cont);
157 /* Return true if the cgroup is a descendant of the current cgroup */
158 int cgroup_is_descendant(const struct cgroup *cont);
160 /* Control Group subsystem type. See Documentation/cgroups.txt for details */
162 struct cgroup_subsys {
163 struct cgroup_subsys_state *(*create)(struct cgroup_subsys *ss,
164 struct cgroup *cont);
165 void (*destroy)(struct cgroup_subsys *ss, struct cgroup *cont);
166 int (*can_attach)(struct cgroup_subsys *ss,
167 struct cgroup *cont, struct task_struct *tsk);
168 void (*attach)(struct cgroup_subsys *ss, struct cgroup *cont,
169 struct cgroup *old_cont, struct task_struct *tsk);
170 void (*fork)(struct cgroup_subsys *ss, struct task_struct *task);
171 void (*exit)(struct cgroup_subsys *ss, struct task_struct *task);
172 int (*populate)(struct cgroup_subsys *ss,
173 struct cgroup *cont);
174 void (*bind)(struct cgroup_subsys *ss, struct cgroup *root);
178 #define MAX_CGROUP_TYPE_NAMELEN 32
181 /* Protected by RCU */
182 struct cgroupfs_root *root;
184 struct list_head sibling;
189 #define SUBSYS(_x) extern struct cgroup_subsys _x ## _subsys;
190 #include <linux/cgroup_subsys.h>
193 static inline struct cgroup_subsys_state *cgroup_subsys_state(
194 struct cgroup *cont, int subsys_id)
196 return cont->subsys[subsys_id];
199 static inline struct cgroup_subsys_state *task_subsys_state(
200 struct task_struct *task, int subsys_id)
202 return rcu_dereference(task->cgroups.subsys[subsys_id]);
205 static inline struct cgroup* task_cgroup(struct task_struct *task,
208 return task_subsys_state(task, subsys_id)->cgroup;
211 int cgroup_path(const struct cgroup *cont, char *buf, int buflen);
213 #else /* !CONFIG_CGROUPS */
215 static inline int cgroup_init_early(void) { return 0; }
216 static inline int cgroup_init(void) { return 0; }
217 static inline void cgroup_init_smp(void) {}
219 static inline void cgroup_lock(void) {}
220 static inline void cgroup_unlock(void) {}
222 #endif /* !CONFIG_CGROUPS */
224 #endif /* _LINUX_CGROUP_H */