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#ifndef _LINUX_CGROUP_H
#define _LINUX_CGROUP_H
/*
* cgroup interface
*
* Copyright (C) 2003 BULL SA
* Copyright (C) 2004-2006 Silicon Graphics, Inc.
*
*/
#include <linux/sched.h>
#include <linux/kref.h>
#include <linux/cpumask.h>
#include <linux/nodemask.h>
#include <linux/rcupdate.h>
#ifdef CONFIG_CGROUPS
struct cgroupfs_root;
struct cgroup_subsys;
struct inode;
extern int cgroup_init_early(void);
extern int cgroup_init(void);
extern void cgroup_init_smp(void);
extern void cgroup_lock(void);
extern void cgroup_unlock(void);
/* Per-subsystem/per-cgroup state maintained by the system. */
struct cgroup_subsys_state {
/* The cgroup that this subsystem is attached to. Useful
* for subsystems that want to know about the cgroup
* hierarchy structure */
struct cgroup *cgroup;
/* State maintained by the cgroup system to allow
* subsystems to be "busy". Should be accessed via css_get()
* and css_put() */
atomic_t refcnt;
unsigned long flags;
};
/* bits in struct cgroup_subsys_state flags field */
enum {
CSS_ROOT, /* This CSS is the root of the subsystem */
};
/*
* Call css_get() to hold a reference on the cgroup;
*
*/
static inline void css_get(struct cgroup_subsys_state *css)
{
/* We don't need to reference count the root state */
if (!test_bit(CSS_ROOT, &css->flags))
atomic_inc(&css->refcnt);
}
/*
* css_put() should be called to release a reference taken by
* css_get()
*/
static inline void css_put(struct cgroup_subsys_state *css)
{
if (!test_bit(CSS_ROOT, &css->flags))
atomic_dec(&css->refcnt);
}
struct cgroup {
unsigned long flags; /* "unsigned long" so bitops work */
/* count users of this cgroup. >0 means busy, but doesn't
* necessarily indicate the number of tasks in the
* cgroup */
atomic_t count;
/*
* We link our 'sibling' struct into our parent's 'children'.
* Our children link their 'sibling' into our 'children'.
*/
struct list_head sibling; /* my parent's children */
struct list_head children; /* my children */
struct cgroup *parent; /* my parent */
struct dentry *dentry; /* cgroup fs entry */
/* Private pointers for each registered subsystem */
struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT];
struct cgroupfs_root *root;
struct cgroup *top_cgroup;
};
/* struct cftype:
*
* The files in the cgroup filesystem mostly have a very simple read/write
* handling, some common function will take care of it. Nevertheless some cases
* (read tasks) are special and therefore I define this structure for every
* kind of file.
*
*
* When reading/writing to a file:
* - the cgroup to use in file->f_dentry->d_parent->d_fsdata
* - the 'cftype' of the file is file->f_dentry->d_fsdata
*/
#define MAX_CFTYPE_NAME 64
struct cftype {
/* By convention, the name should begin with the name of the
* subsystem, followed by a period */
char name[MAX_CFTYPE_NAME];
int private;
int (*open) (struct inode *inode, struct file *file);
ssize_t (*read) (struct cgroup *cont, struct cftype *cft,
struct file *file,
char __user *buf, size_t nbytes, loff_t *ppos);
/*
* read_uint() is a shortcut for the common case of returning a
* single integer. Use it in place of read()
*/
u64 (*read_uint) (struct cgroup *cont, struct cftype *cft);
ssize_t (*write) (struct cgroup *cont, struct cftype *cft,
struct file *file,
const char __user *buf, size_t nbytes, loff_t *ppos);
int (*release) (struct inode *inode, struct file *file);
};
/* Add a new file to the given cgroup directory. Should only be
* called by subsystems from within a populate() method */
int cgroup_add_file(struct cgroup *cont, struct cgroup_subsys *subsys,
const struct cftype *cft);
/* Add a set of new files to the given cgroup directory. Should
* only be called by subsystems from within a populate() method */
int cgroup_add_files(struct cgroup *cont,
struct cgroup_subsys *subsys,
const struct cftype cft[],
int count);
int cgroup_is_removed(const struct cgroup *cont);
int cgroup_path(const struct cgroup *cont, char *buf, int buflen);
int __cgroup_task_count(const struct cgroup *cont);
static inline int cgroup_task_count(const struct cgroup *cont)
{
int task_count;
rcu_read_lock();
task_count = __cgroup_task_count(cont);
rcu_read_unlock();
return task_count;
}
/* Return true if the cgroup is a descendant of the current cgroup */
int cgroup_is_descendant(const struct cgroup *cont);
/* Control Group subsystem type. See Documentation/cgroups.txt for details */
struct cgroup_subsys {
struct cgroup_subsys_state *(*create)(struct cgroup_subsys *ss,
struct cgroup *cont);
void (*destroy)(struct cgroup_subsys *ss, struct cgroup *cont);
int (*can_attach)(struct cgroup_subsys *ss,
struct cgroup *cont, struct task_struct *tsk);
void (*attach)(struct cgroup_subsys *ss, struct cgroup *cont,
struct cgroup *old_cont, struct task_struct *tsk);
void (*fork)(struct cgroup_subsys *ss, struct task_struct *task);
void (*exit)(struct cgroup_subsys *ss, struct task_struct *task);
int (*populate)(struct cgroup_subsys *ss,
struct cgroup *cont);
void (*bind)(struct cgroup_subsys *ss, struct cgroup *root);
int subsys_id;
int active;
int early_init;
#define MAX_CGROUP_TYPE_NAMELEN 32
const char *name;
/* Protected by RCU */
struct cgroupfs_root *root;
struct list_head sibling;
void *private;
};
#define SUBSYS(_x) extern struct cgroup_subsys _x ## _subsys;
#include <linux/cgroup_subsys.h>
#undef SUBSYS
static inline struct cgroup_subsys_state *cgroup_subsys_state(
struct cgroup *cont, int subsys_id)
{
return cont->subsys[subsys_id];
}
static inline struct cgroup_subsys_state *task_subsys_state(
struct task_struct *task, int subsys_id)
{
return rcu_dereference(task->cgroups.subsys[subsys_id]);
}
static inline struct cgroup* task_cgroup(struct task_struct *task,
int subsys_id)
{
return task_subsys_state(task, subsys_id)->cgroup;
}
int cgroup_path(const struct cgroup *cont, char *buf, int buflen);
#else /* !CONFIG_CGROUPS */
static inline int cgroup_init_early(void) { return 0; }
static inline int cgroup_init(void) { return 0; }
static inline void cgroup_init_smp(void) {}
static inline void cgroup_lock(void) {}
static inline void cgroup_unlock(void) {}
#endif /* !CONFIG_CGROUPS */
#endif /* _LINUX_CGROUP_H */
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