| #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/cpumask.h> |
| #include <linux/nodemask.h> |
| #include <linux/rcupdate.h> |
| #include <linux/cgroupstats.h> |
| #include <linux/prio_heap.h> |
| #include <linux/rwsem.h> |
| #include <linux/idr.h> |
| |
| #ifdef CONFIG_CGROUPS |
| |
| struct cgroupfs_root; |
| struct cgroup_subsys; |
| struct inode; |
| struct cgroup; |
| struct css_id; |
| |
| extern int cgroup_init_early(void); |
| extern int cgroup_init(void); |
| extern void cgroup_lock(void); |
| extern int cgroup_lock_is_held(void); |
| extern bool cgroup_lock_live_group(struct cgroup *cgrp); |
| extern void cgroup_unlock(void); |
| extern void cgroup_fork(struct task_struct *p); |
| extern void cgroup_fork_callbacks(struct task_struct *p); |
| extern void cgroup_post_fork(struct task_struct *p); |
| extern void cgroup_exit(struct task_struct *p, int run_callbacks); |
| extern int cgroupstats_build(struct cgroupstats *stats, |
| struct dentry *dentry); |
| extern int cgroup_load_subsys(struct cgroup_subsys *ss); |
| extern void cgroup_unload_subsys(struct cgroup_subsys *ss); |
| |
| extern const struct file_operations proc_cgroup_operations; |
| |
| /* Define the enumeration of all builtin cgroup subsystems */ |
| #define SUBSYS(_x) _x ## _subsys_id, |
| enum cgroup_subsys_id { |
| #include <linux/cgroup_subsys.h> |
| CGROUP_BUILTIN_SUBSYS_COUNT |
| }; |
| #undef SUBSYS |
| /* |
| * This define indicates the maximum number of subsystems that can be loaded |
| * at once. We limit to this many since cgroupfs_root has subsys_bits to keep |
| * track of all of them. |
| */ |
| #define CGROUP_SUBSYS_COUNT (BITS_PER_BYTE*sizeof(unsigned long)) |
| |
| /* 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(), |
| * css_tryget() and and css_put(). |
| */ |
| |
| atomic_t refcnt; |
| |
| unsigned long flags; |
| /* ID for this css, if possible */ |
| struct css_id __rcu *id; |
| }; |
| |
| /* bits in struct cgroup_subsys_state flags field */ |
| enum { |
| CSS_ROOT, /* This CSS is the root of the subsystem */ |
| CSS_REMOVED, /* This CSS is dead */ |
| }; |
| |
| /* Caller must verify that the css is not for root cgroup */ |
| static inline void __css_get(struct cgroup_subsys_state *css, int count) |
| { |
| atomic_add(count, &css->refcnt); |
| } |
| |
| /* |
| * Call css_get() to hold a reference on the css; it can be used |
| * for a reference obtained via: |
| * - an existing ref-counted reference to the css |
| * - task->cgroups for a locked task |
| */ |
| |
| 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)) |
| __css_get(css, 1); |
| } |
| |
| static inline bool css_is_removed(struct cgroup_subsys_state *css) |
| { |
| return test_bit(CSS_REMOVED, &css->flags); |
| } |
| |
| /* |
| * Call css_tryget() to take a reference on a css if your existing |
| * (known-valid) reference isn't already ref-counted. Returns false if |
| * the css has been destroyed. |
| */ |
| |
| static inline bool css_tryget(struct cgroup_subsys_state *css) |
| { |
| if (test_bit(CSS_ROOT, &css->flags)) |
| return true; |
| while (!atomic_inc_not_zero(&css->refcnt)) { |
| if (test_bit(CSS_REMOVED, &css->flags)) |
| return false; |
| cpu_relax(); |
| } |
| return true; |
| } |
| |
| /* |
| * css_put() should be called to release a reference taken by |
| * css_get() or css_tryget() |
| */ |
| |
| extern void __css_put(struct cgroup_subsys_state *css, int count); |
| static inline void css_put(struct cgroup_subsys_state *css) |
| { |
| if (!test_bit(CSS_ROOT, &css->flags)) |
| __css_put(css, 1); |
| } |
| |
| /* bits in struct cgroup flags field */ |
| enum { |
| /* Control Group is dead */ |
| CGRP_REMOVED, |
| /* |
| * Control Group has previously had a child cgroup or a task, |
| * but no longer (only if CGRP_NOTIFY_ON_RELEASE is set) |
| */ |
| CGRP_RELEASABLE, |
| /* Control Group requires release notifications to userspace */ |
| CGRP_NOTIFY_ON_RELEASE, |
| /* |
| * A thread in rmdir() is wating for this cgroup. |
| */ |
| CGRP_WAIT_ON_RMDIR, |
| /* |
| * Clone cgroup values when creating a new child cgroup |
| */ |
| CGRP_CLONE_CHILDREN, |
| }; |
| |
| /* which pidlist file are we talking about? */ |
| enum cgroup_filetype { |
| CGROUP_FILE_PROCS, |
| CGROUP_FILE_TASKS, |
| }; |
| |
| /* |
| * A pidlist is a list of pids that virtually represents the contents of one |
| * of the cgroup files ("procs" or "tasks"). We keep a list of such pidlists, |
| * a pair (one each for procs, tasks) for each pid namespace that's relevant |
| * to the cgroup. |
| */ |
| struct cgroup_pidlist { |
| /* |
| * used to find which pidlist is wanted. doesn't change as long as |
| * this particular list stays in the list. |
| */ |
| struct { enum cgroup_filetype type; struct pid_namespace *ns; } key; |
| /* array of xids */ |
| pid_t *list; |
| /* how many elements the above list has */ |
| int length; |
| /* how many files are using the current array */ |
| int use_count; |
| /* each of these stored in a list by its cgroup */ |
| struct list_head links; |
| /* pointer to the cgroup we belong to, for list removal purposes */ |
| struct cgroup *owner; |
| /* protects the other fields */ |
| struct rw_semaphore mutex; |
| }; |
| |
| 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 __rcu *dentry; /* cgroup fs entry, RCU protected */ |
| |
| /* Private pointers for each registered subsystem */ |
| struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; |
| |
| struct cgroupfs_root *root; |
| struct cgroup *top_cgroup; |
| |
| /* |
| * List of cg_cgroup_links pointing at css_sets with |
| * tasks in this cgroup. Protected by css_set_lock |
| */ |
| struct list_head css_sets; |
| |
| /* |
| * Linked list running through all cgroups that can |
| * potentially be reaped by the release agent. Protected by |
| * release_list_lock |
| */ |
| struct list_head release_list; |
| |
| /* |
| * list of pidlists, up to two for each namespace (one for procs, one |
| * for tasks); created on demand. |
| */ |
| struct list_head pidlists; |
| struct mutex pidlist_mutex; |
| |
| /* For RCU-protected deletion */ |
| struct rcu_head rcu_head; |
| |
| /* List of events which userspace want to recieve */ |
| struct list_head event_list; |
| spinlock_t event_list_lock; |
| }; |
| |
| /* |
| * A css_set is a structure holding pointers to a set of |
| * cgroup_subsys_state objects. This saves space in the task struct |
| * object and speeds up fork()/exit(), since a single inc/dec and a |
| * list_add()/del() can bump the reference count on the entire cgroup |
| * set for a task. |
| */ |
| |
| struct css_set { |
| |
| /* Reference count */ |
| atomic_t refcount; |
| |
| /* |
| * List running through all cgroup groups in the same hash |
| * slot. Protected by css_set_lock |
| */ |
| struct hlist_node hlist; |
| |
| /* |
| * List running through all tasks using this cgroup |
| * group. Protected by css_set_lock |
| */ |
| struct list_head tasks; |
| |
| /* |
| * List of cg_cgroup_link objects on link chains from |
| * cgroups referenced from this css_set. Protected by |
| * css_set_lock |
| */ |
| struct list_head cg_links; |
| |
| /* |
| * Set of subsystem states, one for each subsystem. This array |
| * is immutable after creation apart from the init_css_set |
| * during subsystem registration (at boot time) and modular subsystem |
| * loading/unloading. |
| */ |
| struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; |
| |
| /* For RCU-protected deletion */ |
| struct rcu_head rcu_head; |
| }; |
| |
| /* |
| * cgroup_map_cb is an abstract callback API for reporting map-valued |
| * control files |
| */ |
| |
| struct cgroup_map_cb { |
| int (*fill)(struct cgroup_map_cb *cb, const char *key, u64 value); |
| void *state; |
| }; |
| |
| /* |
| * struct cftype: handler definitions for cgroup control files |
| * |
| * When reading/writing to a file: |
| * - the cgroup to use is 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; |
| /* |
| * If not 0, file mode is set to this value, otherwise it will |
| * be figured out automatically |
| */ |
| mode_t mode; |
| |
| /* |
| * If non-zero, defines the maximum length of string that can |
| * be passed to write_string; defaults to 64 |
| */ |
| size_t max_write_len; |
| |
| int (*open)(struct inode *inode, struct file *file); |
| ssize_t (*read)(struct cgroup *cgrp, struct cftype *cft, |
| struct file *file, |
| char __user *buf, size_t nbytes, loff_t *ppos); |
| /* |
| * read_u64() is a shortcut for the common case of returning a |
| * single integer. Use it in place of read() |
| */ |
| u64 (*read_u64)(struct cgroup *cgrp, struct cftype *cft); |
| /* |
| * read_s64() is a signed version of read_u64() |
| */ |
| s64 (*read_s64)(struct cgroup *cgrp, struct cftype *cft); |
| /* |
| * read_map() is used for defining a map of key/value |
| * pairs. It should call cb->fill(cb, key, value) for each |
| * entry. The key/value pairs (and their ordering) should not |
| * change between reboots. |
| */ |
| int (*read_map)(struct cgroup *cont, struct cftype *cft, |
| struct cgroup_map_cb *cb); |
| /* |
| * read_seq_string() is used for outputting a simple sequence |
| * using seqfile. |
| */ |
| int (*read_seq_string)(struct cgroup *cont, struct cftype *cft, |
| struct seq_file *m); |
| |
| ssize_t (*write)(struct cgroup *cgrp, struct cftype *cft, |
| struct file *file, |
| const char __user *buf, size_t nbytes, loff_t *ppos); |
| |
| /* |
| * write_u64() is a shortcut for the common case of accepting |
| * a single integer (as parsed by simple_strtoull) from |
| * userspace. Use in place of write(); return 0 or error. |
| */ |
| int (*write_u64)(struct cgroup *cgrp, struct cftype *cft, u64 val); |
| /* |
| * write_s64() is a signed version of write_u64() |
| */ |
| int (*write_s64)(struct cgroup *cgrp, struct cftype *cft, s64 val); |
| |
| /* |
| * write_string() is passed a nul-terminated kernelspace |
| * buffer of maximum length determined by max_write_len. |
| * Returns 0 or -ve error code. |
| */ |
| int (*write_string)(struct cgroup *cgrp, struct cftype *cft, |
| const char *buffer); |
| /* |
| * trigger() callback can be used to get some kick from the |
| * userspace, when the actual string written is not important |
| * at all. The private field can be used to determine the |
| * kick type for multiplexing. |
| */ |
| int (*trigger)(struct cgroup *cgrp, unsigned int event); |
| |
| int (*release)(struct inode *inode, struct file *file); |
| |
| /* |
| * register_event() callback will be used to add new userspace |
| * waiter for changes related to the cftype. Implement it if |
| * you want to provide this functionality. Use eventfd_signal() |
| * on eventfd to send notification to userspace. |
| */ |
| int (*register_event)(struct cgroup *cgrp, struct cftype *cft, |
| struct eventfd_ctx *eventfd, const char *args); |
| /* |
| * unregister_event() callback will be called when userspace |
| * closes the eventfd or on cgroup removing. |
| * This callback must be implemented, if you want provide |
| * notification functionality. |
| */ |
| void (*unregister_event)(struct cgroup *cgrp, struct cftype *cft, |
| struct eventfd_ctx *eventfd); |
| }; |
| |
| struct cgroup_scanner { |
| struct cgroup *cg; |
| int (*test_task)(struct task_struct *p, struct cgroup_scanner *scan); |
| void (*process_task)(struct task_struct *p, |
| struct cgroup_scanner *scan); |
| struct ptr_heap *heap; |
| void *data; |
| }; |
| |
| /* |
| * 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 *cgrp, 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 *cgrp, |
| struct cgroup_subsys *subsys, |
| const struct cftype cft[], |
| int count); |
| |
| int cgroup_is_removed(const struct cgroup *cgrp); |
| |
| int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen); |
| |
| int cgroup_task_count(const struct cgroup *cgrp); |
| |
| /* Return true if cgrp is a descendant of the task's cgroup */ |
| int cgroup_is_descendant(const struct cgroup *cgrp, struct task_struct *task); |
| |
| /* |
| * When the subsys has to access css and may add permanent refcnt to css, |
| * it should take care of racy conditions with rmdir(). Following set of |
| * functions, is for stop/restart rmdir if necessary. |
| * Because these will call css_get/put, "css" should be alive css. |
| * |
| * cgroup_exclude_rmdir(); |
| * ...do some jobs which may access arbitrary empty cgroup |
| * cgroup_release_and_wakeup_rmdir(); |
| * |
| * When someone removes a cgroup while cgroup_exclude_rmdir() holds it, |
| * it sleeps and cgroup_release_and_wakeup_rmdir() will wake him up. |
| */ |
| |
| void cgroup_exclude_rmdir(struct cgroup_subsys_state *css); |
| void cgroup_release_and_wakeup_rmdir(struct cgroup_subsys_state *css); |
| |
| /* |
| * Control Group subsystem type. |
| * See Documentation/cgroups/cgroups.txt for details |
| */ |
| |
| struct cgroup_subsys { |
| struct cgroup_subsys_state *(*create)(struct cgroup_subsys *ss, |
| struct cgroup *cgrp); |
| int (*pre_destroy)(struct cgroup_subsys *ss, struct cgroup *cgrp); |
| void (*destroy)(struct cgroup_subsys *ss, struct cgroup *cgrp); |
| int (*can_attach)(struct cgroup_subsys *ss, struct cgroup *cgrp, |
| struct task_struct *tsk, bool threadgroup); |
| void (*cancel_attach)(struct cgroup_subsys *ss, struct cgroup *cgrp, |
| struct task_struct *tsk, bool threadgroup); |
| void (*attach)(struct cgroup_subsys *ss, struct cgroup *cgrp, |
| struct cgroup *old_cgrp, struct task_struct *tsk, |
| bool threadgroup); |
| 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 *cgrp); |
| void (*post_clone)(struct cgroup_subsys *ss, struct cgroup *cgrp); |
| void (*bind)(struct cgroup_subsys *ss, struct cgroup *root); |
| |
| int subsys_id; |
| int active; |
| int disabled; |
| int early_init; |
| /* |
| * True if this subsys uses ID. ID is not available before cgroup_init() |
| * (not available in early_init time.) |
| */ |
| bool use_id; |
| #define MAX_CGROUP_TYPE_NAMELEN 32 |
| const char *name; |
| |
| /* |
| * Protects sibling/children links of cgroups in this |
| * hierarchy, plus protects which hierarchy (or none) the |
| * subsystem is a part of (i.e. root/sibling). To avoid |
| * potential deadlocks, the following operations should not be |
| * undertaken while holding any hierarchy_mutex: |
| * |
| * - allocating memory |
| * - initiating hotplug events |
| */ |
| struct mutex hierarchy_mutex; |
| struct lock_class_key subsys_key; |
| |
| /* |
| * Link to parent, and list entry in parent's children. |
| * Protected by this->hierarchy_mutex and cgroup_lock() |
| */ |
| struct cgroupfs_root *root; |
| struct list_head sibling; |
| /* used when use_id == true */ |
| struct idr idr; |
| spinlock_t id_lock; |
| |
| /* should be defined only by modular subsystems */ |
| struct module *module; |
| }; |
| |
| #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 *cgrp, int subsys_id) |
| { |
| return cgrp->subsys[subsys_id]; |
| } |
| |
| /* |
| * function to get the cgroup_subsys_state which allows for extra |
| * rcu_dereference_check() conditions, such as locks used during the |
| * cgroup_subsys::attach() methods. |
| */ |
| #define task_subsys_state_check(task, subsys_id, __c) \ |
| rcu_dereference_check(task->cgroups->subsys[subsys_id], \ |
| rcu_read_lock_held() || \ |
| lockdep_is_held(&task->alloc_lock) || \ |
| cgroup_lock_is_held() || (__c)) |
| |
| static inline struct cgroup_subsys_state * |
| task_subsys_state(struct task_struct *task, int subsys_id) |
| { |
| return task_subsys_state_check(task, subsys_id, false); |
| } |
| |
| static inline struct cgroup* task_cgroup(struct task_struct *task, |
| int subsys_id) |
| { |
| return task_subsys_state(task, subsys_id)->cgroup; |
| } |
| |
| int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *ss, |
| char *nodename); |
| |
| /* A cgroup_iter should be treated as an opaque object */ |
| struct cgroup_iter { |
| struct list_head *cg_link; |
| struct list_head *task; |
| }; |
| |
| /* |
| * To iterate across the tasks in a cgroup: |
| * |
| * 1) call cgroup_iter_start to initialize an iterator |
| * |
| * 2) call cgroup_iter_next() to retrieve member tasks until it |
| * returns NULL or until you want to end the iteration |
| * |
| * 3) call cgroup_iter_end() to destroy the iterator. |
| * |
| * Or, call cgroup_scan_tasks() to iterate through every task in a |
| * cgroup - cgroup_scan_tasks() holds the css_set_lock when calling |
| * the test_task() callback, but not while calling the process_task() |
| * callback. |
| */ |
| void cgroup_iter_start(struct cgroup *cgrp, struct cgroup_iter *it); |
| struct task_struct *cgroup_iter_next(struct cgroup *cgrp, |
| struct cgroup_iter *it); |
| void cgroup_iter_end(struct cgroup *cgrp, struct cgroup_iter *it); |
| int cgroup_scan_tasks(struct cgroup_scanner *scan); |
| int cgroup_attach_task(struct cgroup *, struct task_struct *); |
| int cgroup_attach_task_all(struct task_struct *from, struct task_struct *); |
| |
| static inline int cgroup_attach_task_current_cg(struct task_struct *tsk) |
| { |
| return cgroup_attach_task_all(current, tsk); |
| } |
| |
| /* |
| * CSS ID is ID for cgroup_subsys_state structs under subsys. This only works |
| * if cgroup_subsys.use_id == true. It can be used for looking up and scanning. |
| * CSS ID is assigned at cgroup allocation (create) automatically |
| * and removed when subsys calls free_css_id() function. This is because |
| * the lifetime of cgroup_subsys_state is subsys's matter. |
| * |
| * Looking up and scanning function should be called under rcu_read_lock(). |
| * Taking cgroup_mutex()/hierarchy_mutex() is not necessary for following calls. |
| * But the css returned by this routine can be "not populated yet" or "being |
| * destroyed". The caller should check css and cgroup's status. |
| */ |
| |
| /* |
| * Typically Called at ->destroy(), or somewhere the subsys frees |
| * cgroup_subsys_state. |
| */ |
| void free_css_id(struct cgroup_subsys *ss, struct cgroup_subsys_state *css); |
| |
| /* Find a cgroup_subsys_state which has given ID */ |
| |
| struct cgroup_subsys_state *css_lookup(struct cgroup_subsys *ss, int id); |
| |
| /* |
| * Get a cgroup whose id is greater than or equal to id under tree of root. |
| * Returning a cgroup_subsys_state or NULL. |
| */ |
| struct cgroup_subsys_state *css_get_next(struct cgroup_subsys *ss, int id, |
| struct cgroup_subsys_state *root, int *foundid); |
| |
| /* Returns true if root is ancestor of cg */ |
| bool css_is_ancestor(struct cgroup_subsys_state *cg, |
| const struct cgroup_subsys_state *root); |
| |
| /* Get id and depth of css */ |
| unsigned short css_id(struct cgroup_subsys_state *css); |
| unsigned short css_depth(struct cgroup_subsys_state *css); |
| |
| #else /* !CONFIG_CGROUPS */ |
| |
| static inline int cgroup_init_early(void) { return 0; } |
| static inline int cgroup_init(void) { return 0; } |
| static inline void cgroup_fork(struct task_struct *p) {} |
| static inline void cgroup_fork_callbacks(struct task_struct *p) {} |
| static inline void cgroup_post_fork(struct task_struct *p) {} |
| static inline void cgroup_exit(struct task_struct *p, int callbacks) {} |
| |
| static inline void cgroup_lock(void) {} |
| static inline void cgroup_unlock(void) {} |
| static inline int cgroupstats_build(struct cgroupstats *stats, |
| struct dentry *dentry) |
| { |
| return -EINVAL; |
| } |
| |
| /* No cgroups - nothing to do */ |
| static inline int cgroup_attach_task_all(struct task_struct *from, |
| struct task_struct *t) |
| { |
| return 0; |
| } |
| static inline int cgroup_attach_task_current_cg(struct task_struct *t) |
| { |
| return 0; |
| } |
| |
| #endif /* !CONFIG_CGROUPS */ |
| |
| #endif /* _LINUX_CGROUP_H */ |