![Linus Torvalds](/assets/img/avatar_default.png)
Pull cgroup changes from Tejun Heo: "This contains two patches, both of which aren't fixes per-se but I think it'd be better to fast-track them. One removes bcache_subsys_id which was added without proper review through the block tree. Fortunately, bcache cgroup code is unconditionally disabled, so this was never exposed to userland. The cgroup subsys_id is removed. Kent will remove the affected (disabled) code through bcache branch. The other simplifies task_group_path_from_hierarchy(). The function doesn't currently have in-kernel users but there are external code and development going on dependent on the function and making the function available for 3.11 would make things go smoother" * 'for-3.11-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: replace task_cgroup_path_from_hierarchy() with task_cgroup_path() cgroup: remove bcache_subsys_id which got added stealthily
907 lines
28 KiB
C
907 lines
28 KiB
C
#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/rculist.h>
|
|
#include <linux/cgroupstats.h>
|
|
#include <linux/prio_heap.h>
|
|
#include <linux/rwsem.h>
|
|
#include <linux/idr.h>
|
|
#include <linux/workqueue.h>
|
|
#include <linux/xattr.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/percpu-refcount.h>
|
|
|
|
#ifdef CONFIG_CGROUPS
|
|
|
|
struct cgroupfs_root;
|
|
struct cgroup_subsys;
|
|
struct inode;
|
|
struct cgroup;
|
|
struct css_id;
|
|
struct eventfd_ctx;
|
|
|
|
extern int cgroup_init_early(void);
|
|
extern int cgroup_init(void);
|
|
extern void cgroup_fork(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 int proc_cgroup_show(struct seq_file *, void *);
|
|
|
|
/*
|
|
* Define the enumeration of all cgroup subsystems.
|
|
*
|
|
* We define ids for builtin subsystems and then modular ones.
|
|
*/
|
|
#define SUBSYS(_x) _x ## _subsys_id,
|
|
enum cgroup_subsys_id {
|
|
#define IS_SUBSYS_ENABLED(option) IS_BUILTIN(option)
|
|
#include <linux/cgroup_subsys.h>
|
|
#undef IS_SUBSYS_ENABLED
|
|
CGROUP_BUILTIN_SUBSYS_COUNT,
|
|
|
|
__CGROUP_SUBSYS_TEMP_PLACEHOLDER = CGROUP_BUILTIN_SUBSYS_COUNT - 1,
|
|
|
|
#define IS_SUBSYS_ENABLED(option) IS_MODULE(option)
|
|
#include <linux/cgroup_subsys.h>
|
|
#undef IS_SUBSYS_ENABLED
|
|
CGROUP_SUBSYS_COUNT,
|
|
};
|
|
#undef SUBSYS
|
|
|
|
/* 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;
|
|
|
|
/* reference count - access via css_[try]get() and css_put() */
|
|
struct percpu_ref refcnt;
|
|
|
|
unsigned long flags;
|
|
/* ID for this css, if possible */
|
|
struct css_id __rcu *id;
|
|
|
|
/* Used to put @cgroup->dentry on the last css_put() */
|
|
struct work_struct dput_work;
|
|
};
|
|
|
|
/* bits in struct cgroup_subsys_state flags field */
|
|
enum {
|
|
CSS_ROOT = (1 << 0), /* this CSS is the root of the subsystem */
|
|
CSS_ONLINE = (1 << 1), /* between ->css_online() and ->css_offline() */
|
|
};
|
|
|
|
/**
|
|
* css_get - obtain a reference on the specified css
|
|
* @css: target css
|
|
*
|
|
* The caller must already have a reference.
|
|
*/
|
|
static inline void css_get(struct cgroup_subsys_state *css)
|
|
{
|
|
/* We don't need to reference count the root state */
|
|
if (!(css->flags & CSS_ROOT))
|
|
percpu_ref_get(&css->refcnt);
|
|
}
|
|
|
|
/**
|
|
* css_tryget - try to obtain a reference on the specified css
|
|
* @css: target css
|
|
*
|
|
* Obtain a reference on @css if it's alive. The caller naturally needs to
|
|
* ensure that @css is accessible but doesn't have to be holding a
|
|
* reference on it - IOW, RCU protected access is good enough for this
|
|
* function. Returns %true if a reference count was successfully obtained;
|
|
* %false otherwise.
|
|
*/
|
|
static inline bool css_tryget(struct cgroup_subsys_state *css)
|
|
{
|
|
if (css->flags & CSS_ROOT)
|
|
return true;
|
|
return percpu_ref_tryget(&css->refcnt);
|
|
}
|
|
|
|
/**
|
|
* css_put - put a css reference
|
|
* @css: target css
|
|
*
|
|
* Put a reference obtained via css_get() and css_tryget().
|
|
*/
|
|
static inline void css_put(struct cgroup_subsys_state *css)
|
|
{
|
|
if (!(css->flags & CSS_ROOT))
|
|
percpu_ref_put(&css->refcnt);
|
|
}
|
|
|
|
/* bits in struct cgroup flags field */
|
|
enum {
|
|
/* Control Group is dead */
|
|
CGRP_DEAD,
|
|
/*
|
|
* 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,
|
|
/*
|
|
* Clone the parent's configuration when creating a new child
|
|
* cpuset cgroup. For historical reasons, this option can be
|
|
* specified at mount time and thus is implemented here.
|
|
*/
|
|
CGRP_CPUSET_CLONE_CHILDREN,
|
|
/* see the comment above CGRP_ROOT_SANE_BEHAVIOR for details */
|
|
CGRP_SANE_BEHAVIOR,
|
|
};
|
|
|
|
struct cgroup_name {
|
|
struct rcu_head rcu_head;
|
|
char name[];
|
|
};
|
|
|
|
struct cgroup {
|
|
unsigned long flags; /* "unsigned long" so bitops work */
|
|
|
|
int id; /* ida allocated in-hierarchy ID */
|
|
|
|
/*
|
|
* 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 list_head files; /* my files */
|
|
|
|
struct cgroup *parent; /* my parent */
|
|
struct dentry *dentry; /* cgroup fs entry, RCU protected */
|
|
|
|
/*
|
|
* Monotonically increasing unique serial number which defines a
|
|
* uniform order among all cgroups. It's guaranteed that all
|
|
* ->children lists are in the ascending order of ->serial_nr.
|
|
* It's used to allow interrupting and resuming iterations.
|
|
*/
|
|
u64 serial_nr;
|
|
|
|
/*
|
|
* This is a copy of dentry->d_name, and it's needed because
|
|
* we can't use dentry->d_name in cgroup_path().
|
|
*
|
|
* You must acquire rcu_read_lock() to access cgrp->name, and
|
|
* the only place that can change it is rename(), which is
|
|
* protected by parent dir's i_mutex.
|
|
*
|
|
* Normally you should use cgroup_name() wrapper rather than
|
|
* access it directly.
|
|
*/
|
|
struct cgroup_name __rcu *name;
|
|
|
|
/* Private pointers for each registered subsystem */
|
|
struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT];
|
|
|
|
struct cgroupfs_root *root;
|
|
|
|
/*
|
|
* List of cgrp_cset_links pointing at css_sets with tasks in this
|
|
* cgroup. Protected by css_set_lock.
|
|
*/
|
|
struct list_head cset_links;
|
|
|
|
/*
|
|
* 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 css percpu_ref killing and RCU-protected deletion */
|
|
struct rcu_head rcu_head;
|
|
struct work_struct destroy_work;
|
|
atomic_t css_kill_cnt;
|
|
|
|
/* List of events which userspace want to receive */
|
|
struct list_head event_list;
|
|
spinlock_t event_list_lock;
|
|
|
|
/* directory xattrs */
|
|
struct simple_xattrs xattrs;
|
|
};
|
|
|
|
#define MAX_CGROUP_ROOT_NAMELEN 64
|
|
|
|
/* cgroupfs_root->flags */
|
|
enum {
|
|
/*
|
|
* Unfortunately, cgroup core and various controllers are riddled
|
|
* with idiosyncrasies and pointless options. The following flag,
|
|
* when set, will force sane behavior - some options are forced on,
|
|
* others are disallowed, and some controllers will change their
|
|
* hierarchical or other behaviors.
|
|
*
|
|
* The set of behaviors affected by this flag are still being
|
|
* determined and developed and the mount option for this flag is
|
|
* prefixed with __DEVEL__. The prefix will be dropped once we
|
|
* reach the point where all behaviors are compatible with the
|
|
* planned unified hierarchy, which will automatically turn on this
|
|
* flag.
|
|
*
|
|
* The followings are the behaviors currently affected this flag.
|
|
*
|
|
* - Mount options "noprefix" and "clone_children" are disallowed.
|
|
* Also, cgroupfs file cgroup.clone_children is not created.
|
|
*
|
|
* - When mounting an existing superblock, mount options should
|
|
* match.
|
|
*
|
|
* - Remount is disallowed.
|
|
*
|
|
* - rename(2) is disallowed.
|
|
*
|
|
* - "tasks" is removed. Everything should be at process
|
|
* granularity. Use "cgroup.procs" instead.
|
|
*
|
|
* - "release_agent" and "notify_on_release" are removed.
|
|
* Replacement notification mechanism will be implemented.
|
|
*
|
|
* - cpuset: tasks will be kept in empty cpusets when hotplug happens
|
|
* and take masks of ancestors with non-empty cpus/mems, instead of
|
|
* being moved to an ancestor.
|
|
*
|
|
* - cpuset: a task can be moved into an empty cpuset, and again it
|
|
* takes masks of ancestors.
|
|
*
|
|
* - memcg: use_hierarchy is on by default and the cgroup file for
|
|
* the flag is not created.
|
|
*
|
|
* - blkcg: blk-throttle becomes properly hierarchical.
|
|
*/
|
|
CGRP_ROOT_SANE_BEHAVIOR = (1 << 0),
|
|
|
|
CGRP_ROOT_NOPREFIX = (1 << 1), /* mounted subsystems have no named prefix */
|
|
CGRP_ROOT_XATTR = (1 << 2), /* supports extended attributes */
|
|
|
|
/* mount options live below bit 16 */
|
|
CGRP_ROOT_OPTION_MASK = (1 << 16) - 1,
|
|
|
|
CGRP_ROOT_SUBSYS_BOUND = (1 << 16), /* subsystems finished binding */
|
|
};
|
|
|
|
/*
|
|
* A cgroupfs_root represents the root of a cgroup hierarchy, and may be
|
|
* associated with a superblock to form an active hierarchy. This is
|
|
* internal to cgroup core. Don't access directly from controllers.
|
|
*/
|
|
struct cgroupfs_root {
|
|
struct super_block *sb;
|
|
|
|
/* The bitmask of subsystems attached to this hierarchy */
|
|
unsigned long subsys_mask;
|
|
|
|
/* Unique id for this hierarchy. */
|
|
int hierarchy_id;
|
|
|
|
/* A list running through the attached subsystems */
|
|
struct list_head subsys_list;
|
|
|
|
/* The root cgroup for this hierarchy */
|
|
struct cgroup top_cgroup;
|
|
|
|
/* Tracks how many cgroups are currently defined in hierarchy.*/
|
|
int number_of_cgroups;
|
|
|
|
/* A list running through the active hierarchies */
|
|
struct list_head root_list;
|
|
|
|
/* Hierarchy-specific flags */
|
|
unsigned long flags;
|
|
|
|
/* IDs for cgroups in this hierarchy */
|
|
struct ida cgroup_ida;
|
|
|
|
/* The path to use for release notifications. */
|
|
char release_agent_path[PATH_MAX];
|
|
|
|
/* The name for this hierarchy - may be empty */
|
|
char name[MAX_CGROUP_ROOT_NAMELEN];
|
|
};
|
|
|
|
/*
|
|
* 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 cgrp_cset_links pointing at cgroups referenced from this
|
|
* css_set. Protected by css_set_lock.
|
|
*/
|
|
struct list_head cgrp_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
|
|
*/
|
|
|
|
/* cftype->flags */
|
|
enum {
|
|
CFTYPE_ONLY_ON_ROOT = (1 << 0), /* only create on root cg */
|
|
CFTYPE_NOT_ON_ROOT = (1 << 1), /* don't create on root cg */
|
|
CFTYPE_INSANE = (1 << 2), /* don't create if sane_behavior */
|
|
};
|
|
|
|
#define MAX_CFTYPE_NAME 64
|
|
|
|
struct cftype {
|
|
/*
|
|
* By convention, the name should begin with the name of the
|
|
* subsystem, followed by a period. Zero length string indicates
|
|
* end of cftype array.
|
|
*/
|
|
char name[MAX_CFTYPE_NAME];
|
|
int private;
|
|
/*
|
|
* If not 0, file mode is set to this value, otherwise it will
|
|
* be figured out automatically
|
|
*/
|
|
umode_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;
|
|
|
|
/* CFTYPE_* flags */
|
|
unsigned int flags;
|
|
|
|
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 *cgrp, 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 *cgrp, 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);
|
|
};
|
|
|
|
/*
|
|
* cftype_sets describe cftypes belonging to a subsystem and are chained at
|
|
* cgroup_subsys->cftsets. Each cftset points to an array of cftypes
|
|
* terminated by zero length name.
|
|
*/
|
|
struct cftype_set {
|
|
struct list_head node; /* chained at subsys->cftsets */
|
|
struct cftype *cfts;
|
|
};
|
|
|
|
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;
|
|
};
|
|
|
|
/*
|
|
* See the comment above CGRP_ROOT_SANE_BEHAVIOR for details. This
|
|
* function can be called as long as @cgrp is accessible.
|
|
*/
|
|
static inline bool cgroup_sane_behavior(const struct cgroup *cgrp)
|
|
{
|
|
return cgrp->root->flags & CGRP_ROOT_SANE_BEHAVIOR;
|
|
}
|
|
|
|
/* Caller should hold rcu_read_lock() */
|
|
static inline const char *cgroup_name(const struct cgroup *cgrp)
|
|
{
|
|
return rcu_dereference(cgrp->name)->name;
|
|
}
|
|
|
|
int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
|
|
int cgroup_rm_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
|
|
|
|
bool cgroup_is_descendant(struct cgroup *cgrp, struct cgroup *ancestor);
|
|
|
|
int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen);
|
|
int task_cgroup_path(struct task_struct *task, char *buf, size_t buflen);
|
|
|
|
int cgroup_task_count(const struct cgroup *cgrp);
|
|
|
|
/*
|
|
* Control Group taskset, used to pass around set of tasks to cgroup_subsys
|
|
* methods.
|
|
*/
|
|
struct cgroup_taskset;
|
|
struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset);
|
|
struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset);
|
|
struct cgroup *cgroup_taskset_cur_cgroup(struct cgroup_taskset *tset);
|
|
int cgroup_taskset_size(struct cgroup_taskset *tset);
|
|
|
|
/**
|
|
* cgroup_taskset_for_each - iterate cgroup_taskset
|
|
* @task: the loop cursor
|
|
* @skip_cgrp: skip if task's cgroup matches this, %NULL to iterate through all
|
|
* @tset: taskset to iterate
|
|
*/
|
|
#define cgroup_taskset_for_each(task, skip_cgrp, tset) \
|
|
for ((task) = cgroup_taskset_first((tset)); (task); \
|
|
(task) = cgroup_taskset_next((tset))) \
|
|
if (!(skip_cgrp) || \
|
|
cgroup_taskset_cur_cgroup((tset)) != (skip_cgrp))
|
|
|
|
/*
|
|
* Control Group subsystem type.
|
|
* See Documentation/cgroups/cgroups.txt for details
|
|
*/
|
|
|
|
struct cgroup_subsys {
|
|
struct cgroup_subsys_state *(*css_alloc)(struct cgroup *cgrp);
|
|
int (*css_online)(struct cgroup *cgrp);
|
|
void (*css_offline)(struct cgroup *cgrp);
|
|
void (*css_free)(struct cgroup *cgrp);
|
|
|
|
int (*can_attach)(struct cgroup *cgrp, struct cgroup_taskset *tset);
|
|
void (*cancel_attach)(struct cgroup *cgrp, struct cgroup_taskset *tset);
|
|
void (*attach)(struct cgroup *cgrp, struct cgroup_taskset *tset);
|
|
void (*fork)(struct task_struct *task);
|
|
void (*exit)(struct cgroup *cgrp, struct cgroup *old_cgrp,
|
|
struct task_struct *task);
|
|
void (*bind)(struct cgroup *root);
|
|
|
|
int subsys_id;
|
|
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;
|
|
|
|
/*
|
|
* If %false, this subsystem is properly hierarchical -
|
|
* configuration, resource accounting and restriction on a parent
|
|
* cgroup cover those of its children. If %true, hierarchy support
|
|
* is broken in some ways - some subsystems ignore hierarchy
|
|
* completely while others are only implemented half-way.
|
|
*
|
|
* It's now disallowed to create nested cgroups if the subsystem is
|
|
* broken and cgroup core will emit a warning message on such
|
|
* cases. Eventually, all subsystems will be made properly
|
|
* hierarchical and this will go away.
|
|
*/
|
|
bool broken_hierarchy;
|
|
bool warned_broken_hierarchy;
|
|
|
|
#define MAX_CGROUP_TYPE_NAMELEN 32
|
|
const char *name;
|
|
|
|
/*
|
|
* Link to parent, and list entry in parent's children.
|
|
* Protected by cgroup_lock()
|
|
*/
|
|
struct cgroupfs_root *root;
|
|
struct list_head sibling;
|
|
/* used when use_id == true */
|
|
struct idr idr;
|
|
spinlock_t id_lock;
|
|
|
|
/* list of cftype_sets */
|
|
struct list_head cftsets;
|
|
|
|
/* base cftypes, automatically [de]registered with subsys itself */
|
|
struct cftype *base_cftypes;
|
|
struct cftype_set base_cftset;
|
|
|
|
/* should be defined only by modular subsystems */
|
|
struct module *module;
|
|
};
|
|
|
|
#define SUBSYS(_x) extern struct cgroup_subsys _x ## _subsys;
|
|
#define IS_SUBSYS_ENABLED(option) IS_BUILTIN(option)
|
|
#include <linux/cgroup_subsys.h>
|
|
#undef IS_SUBSYS_ENABLED
|
|
#undef SUBSYS
|
|
|
|
static inline struct cgroup_subsys_state *cgroup_subsys_state(
|
|
struct cgroup *cgrp, int subsys_id)
|
|
{
|
|
return cgrp->subsys[subsys_id];
|
|
}
|
|
|
|
/**
|
|
* task_css_set_check - obtain a task's css_set with extra access conditions
|
|
* @task: the task to obtain css_set for
|
|
* @__c: extra condition expression to be passed to rcu_dereference_check()
|
|
*
|
|
* A task's css_set is RCU protected, initialized and exited while holding
|
|
* task_lock(), and can only be modified while holding both cgroup_mutex
|
|
* and task_lock() while the task is alive. This macro verifies that the
|
|
* caller is inside proper critical section and returns @task's css_set.
|
|
*
|
|
* The caller can also specify additional allowed conditions via @__c, such
|
|
* as locks used during the cgroup_subsys::attach() methods.
|
|
*/
|
|
#ifdef CONFIG_PROVE_RCU
|
|
extern struct mutex cgroup_mutex;
|
|
#define task_css_set_check(task, __c) \
|
|
rcu_dereference_check((task)->cgroups, \
|
|
lockdep_is_held(&(task)->alloc_lock) || \
|
|
lockdep_is_held(&cgroup_mutex) || (__c))
|
|
#else
|
|
#define task_css_set_check(task, __c) \
|
|
rcu_dereference((task)->cgroups)
|
|
#endif
|
|
|
|
/**
|
|
* task_subsys_state_check - obtain css for (task, subsys) w/ extra access conds
|
|
* @task: the target task
|
|
* @subsys_id: the target subsystem ID
|
|
* @__c: extra condition expression to be passed to rcu_dereference_check()
|
|
*
|
|
* Return the cgroup_subsys_state for the (@task, @subsys_id) pair. The
|
|
* synchronization rules are the same as task_css_set_check().
|
|
*/
|
|
#define task_subsys_state_check(task, subsys_id, __c) \
|
|
task_css_set_check((task), (__c))->subsys[(subsys_id)]
|
|
|
|
/**
|
|
* task_css_set - obtain a task's css_set
|
|
* @task: the task to obtain css_set for
|
|
*
|
|
* See task_css_set_check().
|
|
*/
|
|
static inline struct css_set *task_css_set(struct task_struct *task)
|
|
{
|
|
return task_css_set_check(task, false);
|
|
}
|
|
|
|
/**
|
|
* task_subsys_state - obtain css for (task, subsys)
|
|
* @task: the target task
|
|
* @subsys_id: the target subsystem ID
|
|
*
|
|
* See task_subsys_state_check().
|
|
*/
|
|
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;
|
|
}
|
|
|
|
struct cgroup *cgroup_next_sibling(struct cgroup *pos);
|
|
|
|
/**
|
|
* cgroup_for_each_child - iterate through children of a cgroup
|
|
* @pos: the cgroup * to use as the loop cursor
|
|
* @cgrp: cgroup whose children to walk
|
|
*
|
|
* Walk @cgrp's children. Must be called under rcu_read_lock(). A child
|
|
* cgroup which hasn't finished ->css_online() or already has finished
|
|
* ->css_offline() may show up during traversal and it's each subsystem's
|
|
* responsibility to verify that each @pos is alive.
|
|
*
|
|
* If a subsystem synchronizes against the parent in its ->css_online() and
|
|
* before starting iterating, a cgroup which finished ->css_online() is
|
|
* guaranteed to be visible in the future iterations.
|
|
*
|
|
* It is allowed to temporarily drop RCU read lock during iteration. The
|
|
* caller is responsible for ensuring that @pos remains accessible until
|
|
* the start of the next iteration by, for example, bumping the css refcnt.
|
|
*/
|
|
#define cgroup_for_each_child(pos, cgrp) \
|
|
for ((pos) = list_first_or_null_rcu(&(cgrp)->children, \
|
|
struct cgroup, sibling); \
|
|
(pos); (pos) = cgroup_next_sibling((pos)))
|
|
|
|
struct cgroup *cgroup_next_descendant_pre(struct cgroup *pos,
|
|
struct cgroup *cgroup);
|
|
struct cgroup *cgroup_rightmost_descendant(struct cgroup *pos);
|
|
|
|
/**
|
|
* cgroup_for_each_descendant_pre - pre-order walk of a cgroup's descendants
|
|
* @pos: the cgroup * to use as the loop cursor
|
|
* @cgroup: cgroup whose descendants to walk
|
|
*
|
|
* Walk @cgroup's descendants. Must be called under rcu_read_lock(). A
|
|
* descendant cgroup which hasn't finished ->css_online() or already has
|
|
* finished ->css_offline() may show up during traversal and it's each
|
|
* subsystem's responsibility to verify that each @pos is alive.
|
|
*
|
|
* If a subsystem synchronizes against the parent in its ->css_online() and
|
|
* before starting iterating, and synchronizes against @pos on each
|
|
* iteration, any descendant cgroup which finished ->css_online() is
|
|
* guaranteed to be visible in the future iterations.
|
|
*
|
|
* In other words, the following guarantees that a descendant can't escape
|
|
* state updates of its ancestors.
|
|
*
|
|
* my_online(@cgrp)
|
|
* {
|
|
* Lock @cgrp->parent and @cgrp;
|
|
* Inherit state from @cgrp->parent;
|
|
* Unlock both.
|
|
* }
|
|
*
|
|
* my_update_state(@cgrp)
|
|
* {
|
|
* Lock @cgrp;
|
|
* Update @cgrp's state;
|
|
* Unlock @cgrp;
|
|
*
|
|
* cgroup_for_each_descendant_pre(@pos, @cgrp) {
|
|
* Lock @pos;
|
|
* Verify @pos is alive and inherit state from @pos->parent;
|
|
* Unlock @pos;
|
|
* }
|
|
* }
|
|
*
|
|
* As long as the inheriting step, including checking the parent state, is
|
|
* enclosed inside @pos locking, double-locking the parent isn't necessary
|
|
* while inheriting. The state update to the parent is guaranteed to be
|
|
* visible by walking order and, as long as inheriting operations to the
|
|
* same @pos are atomic to each other, multiple updates racing each other
|
|
* still result in the correct state. It's guaranateed that at least one
|
|
* inheritance happens for any cgroup after the latest update to its
|
|
* parent.
|
|
*
|
|
* If checking parent's state requires locking the parent, each inheriting
|
|
* iteration should lock and unlock both @pos->parent and @pos.
|
|
*
|
|
* Alternatively, a subsystem may choose to use a single global lock to
|
|
* synchronize ->css_online() and ->css_offline() against tree-walking
|
|
* operations.
|
|
*
|
|
* It is allowed to temporarily drop RCU read lock during iteration. The
|
|
* caller is responsible for ensuring that @pos remains accessible until
|
|
* the start of the next iteration by, for example, bumping the css refcnt.
|
|
*/
|
|
#define cgroup_for_each_descendant_pre(pos, cgroup) \
|
|
for (pos = cgroup_next_descendant_pre(NULL, (cgroup)); (pos); \
|
|
pos = cgroup_next_descendant_pre((pos), (cgroup)))
|
|
|
|
struct cgroup *cgroup_next_descendant_post(struct cgroup *pos,
|
|
struct cgroup *cgroup);
|
|
|
|
/**
|
|
* cgroup_for_each_descendant_post - post-order walk of a cgroup's descendants
|
|
* @pos: the cgroup * to use as the loop cursor
|
|
* @cgroup: cgroup whose descendants to walk
|
|
*
|
|
* Similar to cgroup_for_each_descendant_pre() but performs post-order
|
|
* traversal instead. Note that the walk visibility guarantee described in
|
|
* pre-order walk doesn't apply the same to post-order walks.
|
|
*/
|
|
#define cgroup_for_each_descendant_post(pos, cgroup) \
|
|
for (pos = cgroup_next_descendant_post(NULL, (cgroup)); (pos); \
|
|
pos = cgroup_next_descendant_post((pos), (cgroup)))
|
|
|
|
/* A cgroup_iter should be treated as an opaque object */
|
|
struct cgroup_iter {
|
|
struct list_head *cset_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_all(struct task_struct *from, struct task_struct *);
|
|
int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from);
|
|
|
|
/*
|
|
* 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 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);
|
|
|
|
/* 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);
|
|
struct cgroup_subsys_state *cgroup_css_from_dir(struct file *f, int id);
|
|
|
|
#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_post_fork(struct task_struct *p) {}
|
|
static inline void cgroup_exit(struct task_struct *p, int callbacks) {}
|
|
|
|
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;
|
|
}
|
|
|
|
#endif /* !CONFIG_CGROUPS */
|
|
|
|
#endif /* _LINUX_CGROUP_H */
|