*/
#include <linux/sched.h>
-#include <linux/kref.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_init_smp(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
+ /*
+ * The cgroup that this subsystem is attached to. Useful
* for subsystems that want to know about the cgroup
- * hierarchy structure */
+ * 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() */
+ /*
+ * 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 *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 cgroup;
- *
+ * 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))
- atomic_inc(&css->refcnt);
+ __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()
+ * 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))
- atomic_dec(&css->refcnt);
+ __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,
+};
+
+/* 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 */
+ /*
+ * count users of this cgroup. >0 means busy, but doesn't
+ * necessarily indicate the number of tasks in the cgroup
+ */
atomic_t count;
/*
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 */
+ struct cgroup *parent; /* my parent */
+ struct dentry *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;
};
-/* 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.
- *
+/*
+ * 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 in file->f_dentry->d_parent->d_fsdata
+ * - 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 */
+ /*
+ * 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
+ * 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_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);
+ 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.
+ */
+ int (*unregister_event)(struct cgroup *cgrp, struct cftype *cft,
+ struct eventfd_ctx *eventfd);
};
-/* 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,
+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 *cont,
+/*
+ * 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 *cont);
+int cgroup_is_removed(const struct cgroup *cgrp);
-int cgroup_path(const struct cgroup *cont, char *buf, int buflen);
+int cgroup_path(const struct cgroup *cgrp, 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;
-}
+int cgroup_task_count(const struct cgroup *cgrp);
-/* Return true if the cgroup is a descendant of the current cgroup */
-int cgroup_is_descendant(const struct cgroup *cont);
+/* Return true if cgrp is a descendant of the task's cgroup */
+int cgroup_is_descendant(const struct cgroup *cgrp, struct task_struct *task);
-/* Control Group subsystem type. See Documentation/cgroups.txt for details */
+/*
+ * 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 *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);
+ 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 *cont);
+ 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;
- /* Protected by RCU */
- struct cgroupfs_root *root;
+ /*
+ * 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;
- void *private;
+ /* should be defined only by modular subsystems */
+ struct module *module;
};
#define SUBSYS(_x) extern struct cgroup_subsys _x ## _subsys;
#undef SUBSYS
static inline struct cgroup_subsys_state *cgroup_subsys_state(
- struct cgroup *cont, int subsys_id)
+ struct cgroup *cgrp, int subsys_id)
{
- return cont->subsys[subsys_id];
+ return cgrp->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]);
+ return rcu_dereference_check(task->cgroups->subsys[subsys_id],
+ rcu_read_lock_held() ||
+ lockdep_is_held(&task->alloc_lock) ||
+ cgroup_lock_is_held());
}
static inline struct cgroup* task_cgroup(struct task_struct *task,
return task_subsys_state(task, subsys_id)->cgroup;
}
-int cgroup_path(const struct cgroup *cont, char *buf, int buflen);
+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 intialize 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 *);
+
+/*
+ * 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_init_smp(void) {}
+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;
+}
#endif /* !CONFIG_CGROUPS */
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff