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Diffstat (limited to 'include/linux/workqueue.h')
| -rw-r--r-- | include/linux/workqueue.h | 592 |
1 files changed, 592 insertions, 0 deletions
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h new file mode 100644 index 000000000..deee212af --- /dev/null +++ b/include/linux/workqueue.h @@ -0,0 +1,592 @@ +/* + * workqueue.h --- work queue handling for Linux. + */ + +#ifndef _LINUX_WORKQUEUE_H +#define _LINUX_WORKQUEUE_H + +#include <linux/timer.h> +#include <linux/linkage.h> +#include <linux/bitops.h> +#include <linux/lockdep.h> +#include <linux/threads.h> +#include <linux/atomic.h> +#include <linux/cpumask.h> + +struct workqueue_struct; + +struct work_struct; +typedef void (*work_func_t)(struct work_struct *work); +void delayed_work_timer_fn(unsigned long __data); + +/* + * The first word is the work queue pointer and the flags rolled into + * one + */ +#define work_data_bits(work) ((unsigned long *)(&(work)->data)) + +enum { + WORK_STRUCT_PENDING_BIT = 0, /* work item is pending execution */ + WORK_STRUCT_DELAYED_BIT = 1, /* work item is delayed */ + WORK_STRUCT_PWQ_BIT = 2, /* data points to pwq */ + WORK_STRUCT_LINKED_BIT = 3, /* next work is linked to this one */ +#ifdef CONFIG_DEBUG_OBJECTS_WORK + WORK_STRUCT_STATIC_BIT = 4, /* static initializer (debugobjects) */ + WORK_STRUCT_COLOR_SHIFT = 5, /* color for workqueue flushing */ +#else + WORK_STRUCT_COLOR_SHIFT = 4, /* color for workqueue flushing */ +#endif + + WORK_STRUCT_COLOR_BITS = 4, + + WORK_STRUCT_PENDING = 1 << WORK_STRUCT_PENDING_BIT, + WORK_STRUCT_DELAYED = 1 << WORK_STRUCT_DELAYED_BIT, + WORK_STRUCT_PWQ = 1 << WORK_STRUCT_PWQ_BIT, + WORK_STRUCT_LINKED = 1 << WORK_STRUCT_LINKED_BIT, +#ifdef CONFIG_DEBUG_OBJECTS_WORK + WORK_STRUCT_STATIC = 1 << WORK_STRUCT_STATIC_BIT, +#else + WORK_STRUCT_STATIC = 0, +#endif + + /* + * The last color is no color used for works which don't + * participate in workqueue flushing. + */ + WORK_NR_COLORS = (1 << WORK_STRUCT_COLOR_BITS) - 1, + WORK_NO_COLOR = WORK_NR_COLORS, + + /* not bound to any CPU, prefer the local CPU */ + WORK_CPU_UNBOUND = NR_CPUS, + + /* + * Reserve 7 bits off of pwq pointer w/ debugobjects turned off. + * This makes pwqs aligned to 256 bytes and allows 15 workqueue + * flush colors. + */ + WORK_STRUCT_FLAG_BITS = WORK_STRUCT_COLOR_SHIFT + + WORK_STRUCT_COLOR_BITS, + + /* data contains off-queue information when !WORK_STRUCT_PWQ */ + WORK_OFFQ_FLAG_BASE = WORK_STRUCT_COLOR_SHIFT, + + __WORK_OFFQ_CANCELING = WORK_OFFQ_FLAG_BASE, + WORK_OFFQ_CANCELING = (1 << __WORK_OFFQ_CANCELING), + + /* + * When a work item is off queue, its high bits point to the last + * pool it was on. Cap at 31 bits and use the highest number to + * indicate that no pool is associated. + */ + WORK_OFFQ_FLAG_BITS = 1, + WORK_OFFQ_POOL_SHIFT = WORK_OFFQ_FLAG_BASE + WORK_OFFQ_FLAG_BITS, + WORK_OFFQ_LEFT = BITS_PER_LONG - WORK_OFFQ_POOL_SHIFT, + WORK_OFFQ_POOL_BITS = WORK_OFFQ_LEFT <= 31 ? WORK_OFFQ_LEFT : 31, + WORK_OFFQ_POOL_NONE = (1LU << WORK_OFFQ_POOL_BITS) - 1, + + /* convenience constants */ + WORK_STRUCT_FLAG_MASK = (1UL << WORK_STRUCT_FLAG_BITS) - 1, + WORK_STRUCT_WQ_DATA_MASK = ~WORK_STRUCT_FLAG_MASK, + WORK_STRUCT_NO_POOL = (unsigned long)WORK_OFFQ_POOL_NONE << WORK_OFFQ_POOL_SHIFT, + + /* bit mask for work_busy() return values */ + WORK_BUSY_PENDING = 1 << 0, + WORK_BUSY_RUNNING = 1 << 1, + + /* maximum string length for set_worker_desc() */ + WORKER_DESC_LEN = 24, +}; + +struct work_struct { + atomic_long_t data; + struct list_head entry; + work_func_t func; +#ifdef CONFIG_LOCKDEP + struct lockdep_map lockdep_map; +#endif +}; + +#define WORK_DATA_INIT() ATOMIC_LONG_INIT(WORK_STRUCT_NO_POOL) +#define WORK_DATA_STATIC_INIT() \ + ATOMIC_LONG_INIT(WORK_STRUCT_NO_POOL | WORK_STRUCT_STATIC) + +struct delayed_work { + struct work_struct work; + struct timer_list timer; + + /* target workqueue and CPU ->timer uses to queue ->work */ + struct workqueue_struct *wq; + int cpu; +}; + +/* + * A struct for workqueue attributes. This can be used to change + * attributes of an unbound workqueue. + * + * Unlike other fields, ->no_numa isn't a property of a worker_pool. It + * only modifies how apply_workqueue_attrs() select pools and thus doesn't + * participate in pool hash calculations or equality comparisons. + */ +struct workqueue_attrs { + int nice; /* nice level */ + cpumask_var_t cpumask; /* allowed CPUs */ + bool no_numa; /* disable NUMA affinity */ +}; + +static inline struct delayed_work *to_delayed_work(struct work_struct *work) +{ + return container_of(work, struct delayed_work, work); +} + +struct execute_work { + struct work_struct work; +}; + +#ifdef CONFIG_LOCKDEP +/* + * NB: because we have to copy the lockdep_map, setting _key + * here is required, otherwise it could get initialised to the + * copy of the lockdep_map! + */ +#define __WORK_INIT_LOCKDEP_MAP(n, k) \ + .lockdep_map = STATIC_LOCKDEP_MAP_INIT(n, k), +#else +#define __WORK_INIT_LOCKDEP_MAP(n, k) +#endif + +#define __WORK_INITIALIZER(n, f) { \ + .data = WORK_DATA_STATIC_INIT(), \ + .entry = { &(n).entry, &(n).entry }, \ + .func = (f), \ + __WORK_INIT_LOCKDEP_MAP(#n, &(n)) \ + } + +#define __DELAYED_WORK_INITIALIZER(n, f, tflags) { \ + .work = __WORK_INITIALIZER((n).work, (f)), \ + .timer = __TIMER_INITIALIZER(delayed_work_timer_fn, \ + 0, (unsigned long)&(n), \ + (tflags) | TIMER_IRQSAFE), \ + } + +#define DECLARE_WORK(n, f) \ + struct work_struct n = __WORK_INITIALIZER(n, f) + +#define DECLARE_DELAYED_WORK(n, f) \ + struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, 0) + +#define DECLARE_DEFERRABLE_WORK(n, f) \ + struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, TIMER_DEFERRABLE) + +#ifdef CONFIG_DEBUG_OBJECTS_WORK +extern void __init_work(struct work_struct *work, int onstack); +extern void destroy_work_on_stack(struct work_struct *work); +extern void destroy_delayed_work_on_stack(struct delayed_work *work); +static inline unsigned int work_static(struct work_struct *work) +{ + return *work_data_bits(work) & WORK_STRUCT_STATIC; +} +#else +static inline void __init_work(struct work_struct *work, int onstack) { } +static inline void destroy_work_on_stack(struct work_struct *work) { } +static inline void destroy_delayed_work_on_stack(struct delayed_work *work) { } +static inline unsigned int work_static(struct work_struct *work) { return 0; } +#endif + +/* + * initialize all of a work item in one go + * + * NOTE! No point in using "atomic_long_set()": using a direct + * assignment of the work data initializer allows the compiler + * to generate better code. + */ +#ifdef CONFIG_LOCKDEP +#define __INIT_WORK(_work, _func, _onstack) \ + do { \ + static struct lock_class_key __key; \ + \ + __init_work((_work), _onstack); \ + (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \ + lockdep_init_map(&(_work)->lockdep_map, #_work, &__key, 0); \ + INIT_LIST_HEAD(&(_work)->entry); \ + (_work)->func = (_func); \ + } while (0) +#else +#define __INIT_WORK(_work, _func, _onstack) \ + do { \ + __init_work((_work), _onstack); \ + (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \ + INIT_LIST_HEAD(&(_work)->entry); \ + (_work)->func = (_func); \ + } while (0) +#endif + +#define INIT_WORK(_work, _func) \ + __INIT_WORK((_work), (_func), 0) + +#define INIT_WORK_ONSTACK(_work, _func) \ + __INIT_WORK((_work), (_func), 1) + +#define __INIT_DELAYED_WORK(_work, _func, _tflags) \ + do { \ + INIT_WORK(&(_work)->work, (_func)); \ + __setup_timer(&(_work)->timer, delayed_work_timer_fn, \ + (unsigned long)(_work), \ + (_tflags) | TIMER_IRQSAFE); \ + } while (0) + +#define __INIT_DELAYED_WORK_ONSTACK(_work, _func, _tflags) \ + do { \ + INIT_WORK_ONSTACK(&(_work)->work, (_func)); \ + __setup_timer_on_stack(&(_work)->timer, \ + delayed_work_timer_fn, \ + (unsigned long)(_work), \ + (_tflags) | TIMER_IRQSAFE); \ + } while (0) + +#define INIT_DELAYED_WORK(_work, _func) \ + __INIT_DELAYED_WORK(_work, _func, 0) + +#define INIT_DELAYED_WORK_ONSTACK(_work, _func) \ + __INIT_DELAYED_WORK_ONSTACK(_work, _func, 0) + +#define INIT_DEFERRABLE_WORK(_work, _func) \ + __INIT_DELAYED_WORK(_work, _func, TIMER_DEFERRABLE) + +#define INIT_DEFERRABLE_WORK_ONSTACK(_work, _func) \ + __INIT_DELAYED_WORK_ONSTACK(_work, _func, TIMER_DEFERRABLE) + +/** + * work_pending - Find out whether a work item is currently pending + * @work: The work item in question + */ +#define work_pending(work) \ + test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work)) + +/** + * delayed_work_pending - Find out whether a delayable work item is currently + * pending + * @work: The work item in question + */ +#define delayed_work_pending(w) \ + work_pending(&(w)->work) + +/* + * Workqueue flags and constants. For details, please refer to + * Documentation/workqueue.txt. + */ +enum { + WQ_UNBOUND = 1 << 1, /* not bound to any cpu */ + WQ_FREEZABLE = 1 << 2, /* freeze during suspend */ + WQ_MEM_RECLAIM = 1 << 3, /* may be used for memory reclaim */ + WQ_HIGHPRI = 1 << 4, /* high priority */ + WQ_CPU_INTENSIVE = 1 << 5, /* cpu intensive workqueue */ + WQ_SYSFS = 1 << 6, /* visible in sysfs, see wq_sysfs_register() */ + + /* + * Per-cpu workqueues are generally preferred because they tend to + * show better performance thanks to cache locality. Per-cpu + * workqueues exclude the scheduler from choosing the CPU to + * execute the worker threads, which has an unfortunate side effect + * of increasing power consumption. + * + * The scheduler considers a CPU idle if it doesn't have any task + * to execute and tries to keep idle cores idle to conserve power; + * however, for example, a per-cpu work item scheduled from an + * interrupt handler on an idle CPU will force the scheduler to + * excute the work item on that CPU breaking the idleness, which in + * turn may lead to more scheduling choices which are sub-optimal + * in terms of power consumption. + * + * Workqueues marked with WQ_POWER_EFFICIENT are per-cpu by default + * but become unbound if workqueue.power_efficient kernel param is + * specified. Per-cpu workqueues which are identified to + * contribute significantly to power-consumption are identified and + * marked with this flag and enabling the power_efficient mode + * leads to noticeable power saving at the cost of small + * performance disadvantage. + * + * http://thread.gmane.org/gmane.linux.kernel/1480396 + */ + WQ_POWER_EFFICIENT = 1 << 7, + + __WQ_DRAINING = 1 << 16, /* internal: workqueue is draining */ + __WQ_ORDERED = 1 << 17, /* internal: workqueue is ordered */ + + WQ_MAX_ACTIVE = 512, /* I like 512, better ideas? */ + WQ_MAX_UNBOUND_PER_CPU = 4, /* 4 * #cpus for unbound wq */ + WQ_DFL_ACTIVE = WQ_MAX_ACTIVE / 2, +}; + +/* unbound wq's aren't per-cpu, scale max_active according to #cpus */ +#define WQ_UNBOUND_MAX_ACTIVE \ + max_t(int, WQ_MAX_ACTIVE, num_possible_cpus() * WQ_MAX_UNBOUND_PER_CPU) + +/* + * System-wide workqueues which are always present. + * + * system_wq is the one used by schedule[_delayed]_work[_on](). + * Multi-CPU multi-threaded. There are users which expect relatively + * short queue flush time. Don't queue works which can run for too + * long. + * + * system_highpri_wq is similar to system_wq but for work items which + * require WQ_HIGHPRI. + * + * system_long_wq is similar to system_wq but may host long running + * works. Queue flushing might take relatively long. + * + * system_unbound_wq is unbound workqueue. Workers are not bound to + * any specific CPU, not concurrency managed, and all queued works are + * executed immediately as long as max_active limit is not reached and + * resources are available. + * + * system_freezable_wq is equivalent to system_wq except that it's + * freezable. + * + * *_power_efficient_wq are inclined towards saving power and converted + * into WQ_UNBOUND variants if 'wq_power_efficient' is enabled; otherwise, + * they are same as their non-power-efficient counterparts - e.g. + * system_power_efficient_wq is identical to system_wq if + * 'wq_power_efficient' is disabled. See WQ_POWER_EFFICIENT for more info. + */ +extern struct workqueue_struct *system_wq; +extern struct workqueue_struct *system_highpri_wq; +extern struct workqueue_struct *system_long_wq; +extern struct workqueue_struct *system_unbound_wq; +extern struct workqueue_struct *system_freezable_wq; +extern struct workqueue_struct *system_power_efficient_wq; +extern struct workqueue_struct *system_freezable_power_efficient_wq; + +extern struct workqueue_struct * +__alloc_workqueue_key(const char *fmt, unsigned int flags, int max_active, + struct lock_class_key *key, const char *lock_name, ...) __printf(1, 6); + +/** + * alloc_workqueue - allocate a workqueue + * @fmt: printf format for the name of the workqueue + * @flags: WQ_* flags + * @max_active: max in-flight work items, 0 for default + * @args: args for @fmt + * + * Allocate a workqueue with the specified parameters. For detailed + * information on WQ_* flags, please refer to Documentation/workqueue.txt. + * + * The __lock_name macro dance is to guarantee that single lock_class_key + * doesn't end up with different namesm, which isn't allowed by lockdep. + * + * RETURNS: + * Pointer to the allocated workqueue on success, %NULL on failure. + */ +#ifdef CONFIG_LOCKDEP +#define alloc_workqueue(fmt, flags, max_active, args...) \ +({ \ + static struct lock_class_key __key; \ + const char *__lock_name; \ + \ + __lock_name = #fmt#args; \ + \ + __alloc_workqueue_key((fmt), (flags), (max_active), \ + &__key, __lock_name, ##args); \ +}) +#else +#define alloc_workqueue(fmt, flags, max_active, args...) \ + __alloc_workqueue_key((fmt), (flags), (max_active), \ + NULL, NULL, ##args) +#endif + +/** + * alloc_ordered_workqueue - allocate an ordered workqueue + * @fmt: printf format for the name of the workqueue + * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful) + * @args: args for @fmt + * + * Allocate an ordered workqueue. An ordered workqueue executes at + * most one work item at any given time in the queued order. They are + * implemented as unbound workqueues with @max_active of one. + * + * RETURNS: + * Pointer to the allocated workqueue on success, %NULL on failure. + */ +#define alloc_ordered_workqueue(fmt, flags, args...) \ + alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED | (flags), 1, ##args) + +#define create_workqueue(name) \ + alloc_workqueue("%s", WQ_MEM_RECLAIM, 1, (name)) +#define create_freezable_workqueue(name) \ + alloc_workqueue("%s", WQ_FREEZABLE | WQ_UNBOUND | WQ_MEM_RECLAIM, \ + 1, (name)) +#define create_singlethread_workqueue(name) \ + alloc_ordered_workqueue("%s", WQ_MEM_RECLAIM, name) + +extern void destroy_workqueue(struct workqueue_struct *wq); + +struct workqueue_attrs *alloc_workqueue_attrs(gfp_t gfp_mask); +void free_workqueue_attrs(struct workqueue_attrs *attrs); +int apply_workqueue_attrs(struct workqueue_struct *wq, + const struct workqueue_attrs *attrs); + +extern bool queue_work_on(int cpu, struct workqueue_struct *wq, + struct work_struct *work); +extern bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq, + struct delayed_work *work, unsigned long delay); +extern bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq, + struct delayed_work *dwork, unsigned long delay); + +extern void flush_workqueue(struct workqueue_struct *wq); +extern void drain_workqueue(struct workqueue_struct *wq); +extern void flush_scheduled_work(void); + +extern int schedule_on_each_cpu(work_func_t func); + +int execute_in_process_context(work_func_t fn, struct execute_work *); + +extern bool flush_work(struct work_struct *work); +extern bool cancel_work_sync(struct work_struct *work); + +extern bool flush_delayed_work(struct delayed_work *dwork); +extern bool cancel_delayed_work(struct delayed_work *dwork); +extern bool cancel_delayed_work_sync(struct delayed_work *dwork); + +extern void workqueue_set_max_active(struct workqueue_struct *wq, + int max_active); +extern bool current_is_workqueue_rescuer(void); +extern bool workqueue_congested(int cpu, struct workqueue_struct *wq); +extern unsigned int work_busy(struct work_struct *work); +extern __printf(1, 2) void set_worker_desc(const char *fmt, ...); +extern void print_worker_info(const char *log_lvl, struct task_struct *task); +extern void show_workqueue_state(void); + +/** + * queue_work - queue work on a workqueue + * @wq: workqueue to use + * @work: work to queue + * + * Returns %false if @work was already on a queue, %true otherwise. + * + * We queue the work to the CPU on which it was submitted, but if the CPU dies + * it can be processed by another CPU. + */ +static inline bool queue_work(struct workqueue_struct *wq, + struct work_struct *work) +{ + return queue_work_on(WORK_CPU_UNBOUND, wq, work); +} + +/** + * queue_delayed_work - queue work on a workqueue after delay + * @wq: workqueue to use + * @dwork: delayable work to queue + * @delay: number of jiffies to wait before queueing + * + * Equivalent to queue_delayed_work_on() but tries to use the local CPU. + */ +static inline bool queue_delayed_work(struct workqueue_struct *wq, + struct delayed_work *dwork, + unsigned long delay) +{ + return queue_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay); +} + +/** + * mod_delayed_work - modify delay of or queue a delayed work + * @wq: workqueue to use + * @dwork: work to queue + * @delay: number of jiffies to wait before queueing + * + * mod_delayed_work_on() on local CPU. + */ +static inline bool mod_delayed_work(struct workqueue_struct *wq, + struct delayed_work *dwork, + unsigned long delay) +{ + return mod_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay); +} + +/** + * schedule_work_on - put work task on a specific cpu + * @cpu: cpu to put the work task on + * @work: job to be done + * + * This puts a job on a specific cpu + */ +static inline bool schedule_work_on(int cpu, struct work_struct *work) +{ + return queue_work_on(cpu, system_wq, work); +} + +/** + * schedule_work - put work task in global workqueue + * @work: job to be done + * + * Returns %false if @work was already on the kernel-global workqueue and + * %true otherwise. + * + * This puts a job in the kernel-global workqueue if it was not already + * queued and leaves it in the same position on the kernel-global + * workqueue otherwise. + */ +static inline bool schedule_work(struct work_struct *work) +{ + return queue_work(system_wq, work); +} + +/** + * schedule_delayed_work_on - queue work in global workqueue on CPU after delay + * @cpu: cpu to use + * @dwork: job to be done + * @delay: number of jiffies to wait + * + * After waiting for a given time this puts a job in the kernel-global + * workqueue on the specified CPU. + */ +static inline bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork, + unsigned long delay) +{ + return queue_delayed_work_on(cpu, system_wq, dwork, delay); +} + +/** + * schedule_delayed_work - put work task in global workqueue after delay + * @dwork: job to be done + * @delay: number of jiffies to wait or 0 for immediate execution + * + * After waiting for a given time this puts a job in the kernel-global + * workqueue. + */ +static inline bool schedule_delayed_work(struct delayed_work *dwork, + unsigned long delay) +{ + return queue_delayed_work(system_wq, dwork, delay); +} + +/** + * keventd_up - is workqueue initialized yet? + */ +static inline bool keventd_up(void) +{ + return system_wq != NULL; +} + +#ifndef CONFIG_SMP +static inline long work_on_cpu(int cpu, long (*fn)(void *), void *arg) +{ + return fn(arg); +} +#else +long work_on_cpu(int cpu, long (*fn)(void *), void *arg); +#endif /* CONFIG_SMP */ + +#ifdef CONFIG_FREEZER +extern void freeze_workqueues_begin(void); +extern bool freeze_workqueues_busy(void); +extern void thaw_workqueues(void); +#endif /* CONFIG_FREEZER */ + +#ifdef CONFIG_SYSFS +int workqueue_sysfs_register(struct workqueue_struct *wq); +#else /* CONFIG_SYSFS */ +static inline int workqueue_sysfs_register(struct workqueue_struct *wq) +{ return 0; } +#endif /* CONFIG_SYSFS */ + +#endif |