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Diffstat (limited to 'include/linux/cgroup-defs.h')
| -rw-r--r-- | include/linux/cgroup-defs.h | 857 |
1 files changed, 857 insertions, 0 deletions
diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h new file mode 100644 index 000000000..265da00a1 --- /dev/null +++ b/include/linux/cgroup-defs.h @@ -0,0 +1,857 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * linux/cgroup-defs.h - basic definitions for cgroup + * + * This file provides basic type and interface. Include this file directly + * only if necessary to avoid cyclic dependencies. + */ +#ifndef _LINUX_CGROUP_DEFS_H +#define _LINUX_CGROUP_DEFS_H + +#include <linux/limits.h> +#include <linux/list.h> +#include <linux/idr.h> +#include <linux/wait.h> +#include <linux/mutex.h> +#include <linux/rcupdate.h> +#include <linux/refcount.h> +#include <linux/percpu-refcount.h> +#include <linux/percpu-rwsem.h> +#include <linux/u64_stats_sync.h> +#include <linux/workqueue.h> +#include <linux/bpf-cgroup-defs.h> +#include <linux/psi_types.h> + +#ifdef CONFIG_CGROUPS + +struct cgroup; +struct cgroup_root; +struct cgroup_subsys; +struct cgroup_taskset; +struct kernfs_node; +struct kernfs_ops; +struct kernfs_open_file; +struct seq_file; +struct poll_table_struct; + +#define MAX_CGROUP_TYPE_NAMELEN 32 +#define MAX_CGROUP_ROOT_NAMELEN 64 +#define MAX_CFTYPE_NAME 64 + +/* define the enumeration of all cgroup subsystems */ +#define SUBSYS(_x) _x ## _cgrp_id, +enum cgroup_subsys_id { +#include <linux/cgroup_subsys.h> + CGROUP_SUBSYS_COUNT, +}; +#undef SUBSYS + +/* bits in struct cgroup_subsys_state flags field */ +enum { + CSS_NO_REF = (1 << 0), /* no reference counting for this css */ + CSS_ONLINE = (1 << 1), /* between ->css_online() and ->css_offline() */ + CSS_RELEASED = (1 << 2), /* refcnt reached zero, released */ + CSS_VISIBLE = (1 << 3), /* css is visible to userland */ + CSS_DYING = (1 << 4), /* css is dying */ +}; + +/* bits in struct cgroup flags field */ +enum { + /* 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, + + /* Control group has to be frozen. */ + CGRP_FREEZE, + + /* Cgroup is frozen. */ + CGRP_FROZEN, + + /* Control group has to be killed. */ + CGRP_KILL, +}; + +/* cgroup_root->flags */ +enum { + CGRP_ROOT_NOPREFIX = (1 << 1), /* mounted subsystems have no named prefix */ + CGRP_ROOT_XATTR = (1 << 2), /* supports extended attributes */ + + /* + * Consider namespaces as delegation boundaries. If this flag is + * set, controller specific interface files in a namespace root + * aren't writeable from inside the namespace. + */ + CGRP_ROOT_NS_DELEGATE = (1 << 3), + + /* + * Reduce latencies on dynamic cgroup modifications such as task + * migrations and controller on/offs by disabling percpu operation on + * cgroup_threadgroup_rwsem. This makes hot path operations such as + * forks and exits into the slow path and more expensive. + * + * The static usage pattern of creating a cgroup, enabling controllers, + * and then seeding it with CLONE_INTO_CGROUP doesn't require write + * locking cgroup_threadgroup_rwsem and thus doesn't benefit from + * favordynmod. + */ + CGRP_ROOT_FAVOR_DYNMODS = (1 << 4), + + /* + * Enable cpuset controller in v1 cgroup to use v2 behavior. + */ + CGRP_ROOT_CPUSET_V2_MODE = (1 << 16), + + /* + * Enable legacy local memory.events. + */ + CGRP_ROOT_MEMORY_LOCAL_EVENTS = (1 << 17), + + /* + * Enable recursive subtree protection + */ + CGRP_ROOT_MEMORY_RECURSIVE_PROT = (1 << 18), +}; + +/* cftype->flags */ +enum { + CFTYPE_ONLY_ON_ROOT = (1 << 0), /* only create on root cgrp */ + CFTYPE_NOT_ON_ROOT = (1 << 1), /* don't create on root cgrp */ + CFTYPE_NS_DELEGATABLE = (1 << 2), /* writeable beyond delegation boundaries */ + + CFTYPE_NO_PREFIX = (1 << 3), /* (DON'T USE FOR NEW FILES) no subsys prefix */ + CFTYPE_WORLD_WRITABLE = (1 << 4), /* (DON'T USE FOR NEW FILES) S_IWUGO */ + CFTYPE_DEBUG = (1 << 5), /* create when cgroup_debug */ + + /* internal flags, do not use outside cgroup core proper */ + __CFTYPE_ONLY_ON_DFL = (1 << 16), /* only on default hierarchy */ + __CFTYPE_NOT_ON_DFL = (1 << 17), /* not on default hierarchy */ + __CFTYPE_ADDED = (1 << 18), +}; + +/* + * cgroup_file is the handle for a file instance created in a cgroup which + * is used, for example, to generate file changed notifications. This can + * be obtained by setting cftype->file_offset. + */ +struct cgroup_file { + /* do not access any fields from outside cgroup core */ + struct kernfs_node *kn; + unsigned long notified_at; + struct timer_list notify_timer; +}; + +/* + * Per-subsystem/per-cgroup state maintained by the system. This is the + * fundamental structural building block that controllers deal with. + * + * Fields marked with "PI:" are public and immutable and may be accessed + * directly without synchronization. + */ +struct cgroup_subsys_state { + /* PI: the cgroup that this css is attached to */ + struct cgroup *cgroup; + + /* PI: the cgroup subsystem that this css is attached to */ + struct cgroup_subsys *ss; + + /* reference count - access via css_[try]get() and css_put() */ + struct percpu_ref refcnt; + + /* siblings list anchored at the parent's ->children */ + struct list_head sibling; + struct list_head children; + + /* flush target list anchored at cgrp->rstat_css_list */ + struct list_head rstat_css_node; + + /* + * PI: Subsys-unique ID. 0 is unused and root is always 1. The + * matching css can be looked up using css_from_id(). + */ + int id; + + unsigned int flags; + + /* + * Monotonically increasing unique serial number which defines a + * uniform order among all csses. It's guaranteed that all + * ->children lists are in the ascending order of ->serial_nr and + * used to allow interrupting and resuming iterations. + */ + u64 serial_nr; + + /* + * Incremented by online self and children. Used to guarantee that + * parents are not offlined before their children. + */ + atomic_t online_cnt; + + /* percpu_ref killing and RCU release */ + struct work_struct destroy_work; + struct rcu_work destroy_rwork; + + /* + * PI: the parent css. Placed here for cache proximity to following + * fields of the containing structure. + */ + struct cgroup_subsys_state *parent; +}; + +/* + * 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 { + /* + * 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). + */ + struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; + + /* reference count */ + refcount_t refcount; + + /* + * For a domain cgroup, the following points to self. If threaded, + * to the matching cset of the nearest domain ancestor. The + * dom_cset provides access to the domain cgroup and its csses to + * which domain level resource consumptions should be charged. + */ + struct css_set *dom_cset; + + /* the default cgroup associated with this css_set */ + struct cgroup *dfl_cgrp; + + /* internal task count, protected by css_set_lock */ + int nr_tasks; + + /* + * Lists running through all tasks using this cgroup group. + * mg_tasks lists tasks which belong to this cset but are in the + * process of being migrated out or in. Protected by + * css_set_lock, but, during migration, once tasks are moved to + * mg_tasks, it can be read safely while holding cgroup_mutex. + */ + struct list_head tasks; + struct list_head mg_tasks; + struct list_head dying_tasks; + + /* all css_task_iters currently walking this cset */ + struct list_head task_iters; + + /* + * On the default hierarchy, ->subsys[ssid] may point to a css + * attached to an ancestor instead of the cgroup this css_set is + * associated with. The following node is anchored at + * ->subsys[ssid]->cgroup->e_csets[ssid] and provides a way to + * iterate through all css's attached to a given cgroup. + */ + struct list_head e_cset_node[CGROUP_SUBSYS_COUNT]; + + /* all threaded csets whose ->dom_cset points to this cset */ + struct list_head threaded_csets; + struct list_head threaded_csets_node; + + /* + * List running through all cgroup groups in the same hash + * slot. Protected by css_set_lock + */ + struct hlist_node hlist; + + /* + * List of cgrp_cset_links pointing at cgroups referenced from this + * css_set. Protected by css_set_lock. + */ + struct list_head cgrp_links; + + /* + * List of csets participating in the on-going migration either as + * source or destination. Protected by cgroup_mutex. + */ + struct list_head mg_src_preload_node; + struct list_head mg_dst_preload_node; + struct list_head mg_node; + + /* + * If this cset is acting as the source of migration the following + * two fields are set. mg_src_cgrp and mg_dst_cgrp are + * respectively the source and destination cgroups of the on-going + * migration. mg_dst_cset is the destination cset the target tasks + * on this cset should be migrated to. Protected by cgroup_mutex. + */ + struct cgroup *mg_src_cgrp; + struct cgroup *mg_dst_cgrp; + struct css_set *mg_dst_cset; + + /* dead and being drained, ignore for migration */ + bool dead; + + /* For RCU-protected deletion */ + struct rcu_head rcu_head; +}; + +struct cgroup_base_stat { + struct task_cputime cputime; + +#ifdef CONFIG_SCHED_CORE + u64 forceidle_sum; +#endif +}; + +/* + * rstat - cgroup scalable recursive statistics. Accounting is done + * per-cpu in cgroup_rstat_cpu which is then lazily propagated up the + * hierarchy on reads. + * + * When a stat gets updated, the cgroup_rstat_cpu and its ancestors are + * linked into the updated tree. On the following read, propagation only + * considers and consumes the updated tree. This makes reading O(the + * number of descendants which have been active since last read) instead of + * O(the total number of descendants). + * + * This is important because there can be a lot of (draining) cgroups which + * aren't active and stat may be read frequently. The combination can + * become very expensive. By propagating selectively, increasing reading + * frequency decreases the cost of each read. + * + * This struct hosts both the fields which implement the above - + * updated_children and updated_next - and the fields which track basic + * resource statistics on top of it - bsync, bstat and last_bstat. + */ +struct cgroup_rstat_cpu { + /* + * ->bsync protects ->bstat. These are the only fields which get + * updated in the hot path. + */ + struct u64_stats_sync bsync; + struct cgroup_base_stat bstat; + + /* + * Snapshots at the last reading. These are used to calculate the + * deltas to propagate to the global counters. + */ + struct cgroup_base_stat last_bstat; + + /* + * This field is used to record the cumulative per-cpu time of + * the cgroup and its descendants. Currently it can be read via + * eBPF/drgn etc, and we are still trying to determine how to + * expose it in the cgroupfs interface. + */ + struct cgroup_base_stat subtree_bstat; + + /* + * Snapshots at the last reading. These are used to calculate the + * deltas to propagate to the per-cpu subtree_bstat. + */ + struct cgroup_base_stat last_subtree_bstat; + + /* + * Child cgroups with stat updates on this cpu since the last read + * are linked on the parent's ->updated_children through + * ->updated_next. + * + * In addition to being more compact, singly-linked list pointing + * to the cgroup makes it unnecessary for each per-cpu struct to + * point back to the associated cgroup. + * + * Protected by per-cpu cgroup_rstat_cpu_lock. + */ + struct cgroup *updated_children; /* terminated by self cgroup */ + struct cgroup *updated_next; /* NULL iff not on the list */ +}; + +struct cgroup_freezer_state { + /* Should the cgroup and its descendants be frozen. */ + bool freeze; + + /* Should the cgroup actually be frozen? */ + int e_freeze; + + /* Fields below are protected by css_set_lock */ + + /* Number of frozen descendant cgroups */ + int nr_frozen_descendants; + + /* + * Number of tasks, which are counted as frozen: + * frozen, SIGSTOPped, and PTRACEd. + */ + int nr_frozen_tasks; +}; + +struct cgroup { + /* self css with NULL ->ss, points back to this cgroup */ + struct cgroup_subsys_state self; + + unsigned long flags; /* "unsigned long" so bitops work */ + + /* + * The depth this cgroup is at. The root is at depth zero and each + * step down the hierarchy increments the level. This along with + * ancestors[] can determine whether a given cgroup is a + * descendant of another without traversing the hierarchy. + */ + int level; + + /* Maximum allowed descent tree depth */ + int max_depth; + + /* + * Keep track of total numbers of visible and dying descent cgroups. + * Dying cgroups are cgroups which were deleted by a user, + * but are still existing because someone else is holding a reference. + * max_descendants is a maximum allowed number of descent cgroups. + * + * nr_descendants and nr_dying_descendants are protected + * by cgroup_mutex and css_set_lock. It's fine to read them holding + * any of cgroup_mutex and css_set_lock; for writing both locks + * should be held. + */ + int nr_descendants; + int nr_dying_descendants; + int max_descendants; + + /* + * Each non-empty css_set associated with this cgroup contributes + * one to nr_populated_csets. The counter is zero iff this cgroup + * doesn't have any tasks. + * + * All children which have non-zero nr_populated_csets and/or + * nr_populated_children of their own contribute one to either + * nr_populated_domain_children or nr_populated_threaded_children + * depending on their type. Each counter is zero iff all cgroups + * of the type in the subtree proper don't have any tasks. + */ + int nr_populated_csets; + int nr_populated_domain_children; + int nr_populated_threaded_children; + + int nr_threaded_children; /* # of live threaded child cgroups */ + + struct kernfs_node *kn; /* cgroup kernfs entry */ + struct cgroup_file procs_file; /* handle for "cgroup.procs" */ + struct cgroup_file events_file; /* handle for "cgroup.events" */ + + /* handles for "{cpu,memory,io,irq}.pressure" */ + struct cgroup_file psi_files[NR_PSI_RESOURCES]; + + /* + * The bitmask of subsystems enabled on the child cgroups. + * ->subtree_control is the one configured through + * "cgroup.subtree_control" while ->subtree_ss_mask is the effective + * one which may have more subsystems enabled. Controller knobs + * are made available iff it's enabled in ->subtree_control. + */ + u16 subtree_control; + u16 subtree_ss_mask; + u16 old_subtree_control; + u16 old_subtree_ss_mask; + + /* Private pointers for each registered subsystem */ + struct cgroup_subsys_state __rcu *subsys[CGROUP_SUBSYS_COUNT]; + + struct cgroup_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; + + /* + * On the default hierarchy, a css_set for a cgroup with some + * susbsys disabled will point to css's which are associated with + * the closest ancestor which has the subsys enabled. The + * following lists all css_sets which point to this cgroup's css + * for the given subsystem. + */ + struct list_head e_csets[CGROUP_SUBSYS_COUNT]; + + /* + * If !threaded, self. If threaded, it points to the nearest + * domain ancestor. Inside a threaded subtree, cgroups are exempt + * from process granularity and no-internal-task constraint. + * Domain level resource consumptions which aren't tied to a + * specific task are charged to the dom_cgrp. + */ + struct cgroup *dom_cgrp; + struct cgroup *old_dom_cgrp; /* used while enabling threaded */ + + /* per-cpu recursive resource statistics */ + struct cgroup_rstat_cpu __percpu *rstat_cpu; + struct list_head rstat_css_list; + + /* cgroup basic resource statistics */ + struct cgroup_base_stat last_bstat; + struct cgroup_base_stat bstat; + struct prev_cputime prev_cputime; /* for printing out cputime */ + + /* + * 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; + + /* used to wait for offlining of csses */ + wait_queue_head_t offline_waitq; + + /* used to schedule release agent */ + struct work_struct release_agent_work; + + /* used to track pressure stalls */ + struct psi_group *psi; + + /* used to store eBPF programs */ + struct cgroup_bpf bpf; + + /* If there is block congestion on this cgroup. */ + atomic_t congestion_count; + + /* Used to store internal freezer state */ + struct cgroup_freezer_state freezer; + +#ifdef CONFIG_BPF_SYSCALL + struct bpf_local_storage __rcu *bpf_cgrp_storage; +#endif + + /* All ancestors including self */ + struct cgroup *ancestors[]; +}; + +/* + * A cgroup_root represents the root of a cgroup hierarchy, and may be + * associated with a kernfs_root to form an active hierarchy. This is + * internal to cgroup core. Don't access directly from controllers. + */ +struct cgroup_root { + struct kernfs_root *kf_root; + + /* The bitmask of subsystems attached to this hierarchy */ + unsigned int subsys_mask; + + /* Unique id for this hierarchy. */ + int hierarchy_id; + + /* + * The root cgroup. The containing cgroup_root will be destroyed on its + * release. cgrp->ancestors[0] will be used overflowing into the + * following field. cgrp_ancestor_storage must immediately follow. + */ + struct cgroup cgrp; + + /* must follow cgrp for cgrp->ancestors[0], see above */ + struct cgroup *cgrp_ancestor_storage; + + /* Number of cgroups in the hierarchy, used only for /proc/cgroups */ + atomic_t nr_cgrps; + + /* A list running through the active hierarchies */ + struct list_head root_list; + + /* Hierarchy-specific flags */ + unsigned int flags; + + /* 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]; +}; + +/* + * struct cftype: handler definitions for cgroup control files + * + * When reading/writing to a file: + * - the cgroup to use is file->f_path.dentry->d_parent->d_fsdata + * - the 'cftype' of the file is file->f_path.dentry->d_fsdata + */ +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]; + unsigned long private; + + /* + * The maximum length of string, excluding trailing nul, that can + * be passed to write. If < PAGE_SIZE-1, PAGE_SIZE-1 is assumed. + */ + size_t max_write_len; + + /* CFTYPE_* flags */ + unsigned int flags; + + /* + * If non-zero, should contain the offset from the start of css to + * a struct cgroup_file field. cgroup will record the handle of + * the created file into it. The recorded handle can be used as + * long as the containing css remains accessible. + */ + unsigned int file_offset; + + /* + * Fields used for internal bookkeeping. Initialized automatically + * during registration. + */ + struct cgroup_subsys *ss; /* NULL for cgroup core files */ + struct list_head node; /* anchored at ss->cfts */ + struct kernfs_ops *kf_ops; + + int (*open)(struct kernfs_open_file *of); + void (*release)(struct kernfs_open_file *of); + + /* + * 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_subsys_state *css, struct cftype *cft); + /* + * read_s64() is a signed version of read_u64() + */ + s64 (*read_s64)(struct cgroup_subsys_state *css, struct cftype *cft); + + /* generic seq_file read interface */ + int (*seq_show)(struct seq_file *sf, void *v); + + /* optional ops, implement all or none */ + void *(*seq_start)(struct seq_file *sf, loff_t *ppos); + void *(*seq_next)(struct seq_file *sf, void *v, loff_t *ppos); + void (*seq_stop)(struct seq_file *sf, void *v); + + /* + * 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_subsys_state *css, struct cftype *cft, + u64 val); + /* + * write_s64() is a signed version of write_u64() + */ + int (*write_s64)(struct cgroup_subsys_state *css, struct cftype *cft, + s64 val); + + /* + * write() is the generic write callback which maps directly to + * kernfs write operation and overrides all other operations. + * Maximum write size is determined by ->max_write_len. Use + * of_css/cft() to access the associated css and cft. + */ + ssize_t (*write)(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off); + + __poll_t (*poll)(struct kernfs_open_file *of, + struct poll_table_struct *pt); + +#ifdef CONFIG_DEBUG_LOCK_ALLOC + struct lock_class_key lockdep_key; +#endif +}; + +/* + * Control Group subsystem type. + * See Documentation/admin-guide/cgroup-v1/cgroups.rst for details + */ +struct cgroup_subsys { + struct cgroup_subsys_state *(*css_alloc)(struct cgroup_subsys_state *parent_css); + int (*css_online)(struct cgroup_subsys_state *css); + void (*css_offline)(struct cgroup_subsys_state *css); + void (*css_released)(struct cgroup_subsys_state *css); + void (*css_free)(struct cgroup_subsys_state *css); + void (*css_reset)(struct cgroup_subsys_state *css); + void (*css_rstat_flush)(struct cgroup_subsys_state *css, int cpu); + int (*css_extra_stat_show)(struct seq_file *seq, + struct cgroup_subsys_state *css); + int (*css_local_stat_show)(struct seq_file *seq, + struct cgroup_subsys_state *css); + + int (*can_attach)(struct cgroup_taskset *tset); + void (*cancel_attach)(struct cgroup_taskset *tset); + void (*attach)(struct cgroup_taskset *tset); + void (*post_attach)(void); + int (*can_fork)(struct task_struct *task, + struct css_set *cset); + void (*cancel_fork)(struct task_struct *task, struct css_set *cset); + void (*fork)(struct task_struct *task); + void (*exit)(struct task_struct *task); + void (*release)(struct task_struct *task); + void (*bind)(struct cgroup_subsys_state *root_css); + + bool early_init:1; + + /* + * If %true, the controller, on the default hierarchy, doesn't show + * up in "cgroup.controllers" or "cgroup.subtree_control", is + * implicitly enabled on all cgroups on the default hierarchy, and + * bypasses the "no internal process" constraint. This is for + * utility type controllers which is transparent to userland. + * + * An implicit controller can be stolen from the default hierarchy + * anytime and thus must be okay with offline csses from previous + * hierarchies coexisting with csses for the current one. + */ + bool implicit_on_dfl:1; + + /* + * If %true, the controller, supports threaded mode on the default + * hierarchy. In a threaded subtree, both process granularity and + * no-internal-process constraint are ignored and a threaded + * controllers should be able to handle that. + * + * Note that as an implicit controller is automatically enabled on + * all cgroups on the default hierarchy, it should also be + * threaded. implicit && !threaded is not supported. + */ + bool threaded:1; + + /* the following two fields are initialized automatically during boot */ + int id; + const char *name; + + /* optional, initialized automatically during boot if not set */ + const char *legacy_name; + + /* link to parent, protected by cgroup_lock() */ + struct cgroup_root *root; + + /* idr for css->id */ + struct idr css_idr; + + /* + * List of cftypes. Each entry is the first entry of an array + * terminated by zero length name. + */ + struct list_head cfts; + + /* + * Base cftypes which are automatically registered. The two can + * point to the same array. + */ + struct cftype *dfl_cftypes; /* for the default hierarchy */ + struct cftype *legacy_cftypes; /* for the legacy hierarchies */ + + /* + * A subsystem may depend on other subsystems. When such subsystem + * is enabled on a cgroup, the depended-upon subsystems are enabled + * together if available. Subsystems enabled due to dependency are + * not visible to userland until explicitly enabled. The following + * specifies the mask of subsystems that this one depends on. + */ + unsigned int depends_on; +}; + +extern struct percpu_rw_semaphore cgroup_threadgroup_rwsem; + +/** + * cgroup_threadgroup_change_begin - threadgroup exclusion for cgroups + * @tsk: target task + * + * Allows cgroup operations to synchronize against threadgroup changes + * using a percpu_rw_semaphore. + */ +static inline void cgroup_threadgroup_change_begin(struct task_struct *tsk) +{ + percpu_down_read(&cgroup_threadgroup_rwsem); +} + +/** + * cgroup_threadgroup_change_end - threadgroup exclusion for cgroups + * @tsk: target task + * + * Counterpart of cgroup_threadcgroup_change_begin(). + */ +static inline void cgroup_threadgroup_change_end(struct task_struct *tsk) +{ + percpu_up_read(&cgroup_threadgroup_rwsem); +} + +#else /* CONFIG_CGROUPS */ + +#define CGROUP_SUBSYS_COUNT 0 + +static inline void cgroup_threadgroup_change_begin(struct task_struct *tsk) +{ + might_sleep(); +} + +static inline void cgroup_threadgroup_change_end(struct task_struct *tsk) {} + +#endif /* CONFIG_CGROUPS */ + +#ifdef CONFIG_SOCK_CGROUP_DATA + +/* + * sock_cgroup_data is embedded at sock->sk_cgrp_data and contains + * per-socket cgroup information except for memcg association. + * + * On legacy hierarchies, net_prio and net_cls controllers directly + * set attributes on each sock which can then be tested by the network + * layer. On the default hierarchy, each sock is associated with the + * cgroup it was created in and the networking layer can match the + * cgroup directly. + */ +struct sock_cgroup_data { + struct cgroup *cgroup; /* v2 */ +#ifdef CONFIG_CGROUP_NET_CLASSID + u32 classid; /* v1 */ +#endif +#ifdef CONFIG_CGROUP_NET_PRIO + u16 prioidx; /* v1 */ +#endif +}; + +static inline u16 sock_cgroup_prioidx(const struct sock_cgroup_data *skcd) +{ +#ifdef CONFIG_CGROUP_NET_PRIO + return READ_ONCE(skcd->prioidx); +#else + return 1; +#endif +} + +static inline u32 sock_cgroup_classid(const struct sock_cgroup_data *skcd) +{ +#ifdef CONFIG_CGROUP_NET_CLASSID + return READ_ONCE(skcd->classid); +#else + return 0; +#endif +} + +static inline void sock_cgroup_set_prioidx(struct sock_cgroup_data *skcd, + u16 prioidx) +{ +#ifdef CONFIG_CGROUP_NET_PRIO + WRITE_ONCE(skcd->prioidx, prioidx); +#endif +} + +static inline void sock_cgroup_set_classid(struct sock_cgroup_data *skcd, + u32 classid) +{ +#ifdef CONFIG_CGROUP_NET_CLASSID + WRITE_ONCE(skcd->classid, classid); +#endif +} + +#else /* CONFIG_SOCK_CGROUP_DATA */ + +struct sock_cgroup_data { +}; + +#endif /* CONFIG_SOCK_CGROUP_DATA */ + +#endif /* _LINUX_CGROUP_DEFS_H */ |