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
);
130 * write_uint() is a shortcut for the common case of accepting
131 * a single integer (as parsed by simple_strtoull) from
132 * userspace. Use in place of write(); return 0 or error.
134 int (*write_uint
) (struct cgroup
*cont
, struct cftype
*cft
, u64 val
);
136 int (*release
) (struct inode
*inode
, struct file
*file
);
139 /* Add a new file to the given cgroup directory. Should only be
140 * called by subsystems from within a populate() method */
141 int cgroup_add_file(struct cgroup
*cont
, struct cgroup_subsys
*subsys
,
142 const struct cftype
*cft
);
144 /* Add a set of new files to the given cgroup directory. Should
145 * only be called by subsystems from within a populate() method */
146 int cgroup_add_files(struct cgroup
*cont
,
147 struct cgroup_subsys
*subsys
,
148 const struct cftype cft
[],
151 int cgroup_is_removed(const struct cgroup
*cont
);
153 int cgroup_path(const struct cgroup
*cont
, char *buf
, int buflen
);
155 int __cgroup_task_count(const struct cgroup
*cont
);
156 static inline int cgroup_task_count(const struct cgroup
*cont
)
160 task_count
= __cgroup_task_count(cont
);
165 /* Return true if the cgroup is a descendant of the current cgroup */
166 int cgroup_is_descendant(const struct cgroup
*cont
);
168 /* Control Group subsystem type. See Documentation/cgroups.txt for details */
170 struct cgroup_subsys
{
171 struct cgroup_subsys_state
*(*create
)(struct cgroup_subsys
*ss
,
172 struct cgroup
*cont
);
173 void (*destroy
)(struct cgroup_subsys
*ss
, struct cgroup
*cont
);
174 int (*can_attach
)(struct cgroup_subsys
*ss
,
175 struct cgroup
*cont
, struct task_struct
*tsk
);
176 void (*attach
)(struct cgroup_subsys
*ss
, struct cgroup
*cont
,
177 struct cgroup
*old_cont
, struct task_struct
*tsk
);
178 void (*fork
)(struct cgroup_subsys
*ss
, struct task_struct
*task
);
179 void (*exit
)(struct cgroup_subsys
*ss
, struct task_struct
*task
);
180 int (*populate
)(struct cgroup_subsys
*ss
,
181 struct cgroup
*cont
);
182 void (*bind
)(struct cgroup_subsys
*ss
, struct cgroup
*root
);
186 #define MAX_CGROUP_TYPE_NAMELEN 32
189 /* Protected by RCU */
190 struct cgroupfs_root
*root
;
192 struct list_head sibling
;
197 #define SUBSYS(_x) extern struct cgroup_subsys _x ## _subsys;
198 #include <linux/cgroup_subsys.h>
201 static inline struct cgroup_subsys_state
*cgroup_subsys_state(
202 struct cgroup
*cont
, int subsys_id
)
204 return cont
->subsys
[subsys_id
];
207 static inline struct cgroup_subsys_state
*task_subsys_state(
208 struct task_struct
*task
, int subsys_id
)
210 return rcu_dereference(task
->cgroups
.subsys
[subsys_id
]);
213 static inline struct cgroup
* task_cgroup(struct task_struct
*task
,
216 return task_subsys_state(task
, subsys_id
)->cgroup
;
219 int cgroup_path(const struct cgroup
*cont
, char *buf
, int buflen
);
221 #else /* !CONFIG_CGROUPS */
223 static inline int cgroup_init_early(void) { return 0; }
224 static inline int cgroup_init(void) { return 0; }
225 static inline void cgroup_init_smp(void) {}
227 static inline void cgroup_lock(void) {}
228 static inline void cgroup_unlock(void) {}
230 #endif /* !CONFIG_CGROUPS */
232 #endif /* _LINUX_CGROUP_H */
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