268 lines
9.1 KiB
C
268 lines
9.1 KiB
C
/*
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* workqueue.h --- work queue handling for Linux.
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*/
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#ifndef _LINUX_WORKQUEUE_H
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#define _LINUX_WORKQUEUE_H
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#include <linux/list.h>
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#include <linux/linkage.h>
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#include <linux/bitops.h>
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#include <linux/lockdep.h>
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#include <linux/threads.h>
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#include <linux/atomic.h>
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#include <linux/spinlock.h>
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struct workqueue_struct;
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struct work_struct;
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typedef void (*work_func_t)(struct work_struct *work);
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void __stdcall delayed_work_timer_fn(unsigned long __data);
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/*
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* The first word is the work queue pointer and the flags rolled into
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* one
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*/
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#define work_data_bits(work) ((unsigned long *)(&(work)->data))
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enum {
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WORK_STRUCT_PENDING_BIT = 0, /* work item is pending execution */
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WORK_STRUCT_DELAYED_BIT = 1, /* work item is delayed */
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WORK_STRUCT_PWQ_BIT = 2, /* data points to pwq */
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WORK_STRUCT_LINKED_BIT = 3, /* next work is linked to this one */
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#ifdef CONFIG_DEBUG_OBJECTS_WORK
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WORK_STRUCT_STATIC_BIT = 4, /* static initializer (debugobjects) */
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WORK_STRUCT_COLOR_SHIFT = 5, /* color for workqueue flushing */
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#else
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WORK_STRUCT_COLOR_SHIFT = 4, /* color for workqueue flushing */
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#endif
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WORK_STRUCT_COLOR_BITS = 4,
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WORK_STRUCT_PENDING = 1 << WORK_STRUCT_PENDING_BIT,
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WORK_STRUCT_DELAYED = 1 << WORK_STRUCT_DELAYED_BIT,
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WORK_STRUCT_PWQ = 1 << WORK_STRUCT_PWQ_BIT,
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WORK_STRUCT_LINKED = 1 << WORK_STRUCT_LINKED_BIT,
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#ifdef CONFIG_DEBUG_OBJECTS_WORK
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WORK_STRUCT_STATIC = 1 << WORK_STRUCT_STATIC_BIT,
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#else
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WORK_STRUCT_STATIC = 0,
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#endif
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/*
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* The last color is no color used for works which don't
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* participate in workqueue flushing.
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*/
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WORK_NR_COLORS = (1 << WORK_STRUCT_COLOR_BITS) - 1,
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WORK_NO_COLOR = WORK_NR_COLORS,
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/* not bound to any CPU, prefer the local CPU */
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WORK_CPU_UNBOUND = NR_CPUS,
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/*
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* Reserve 7 bits off of pwq pointer w/ debugobjects turned off.
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* This makes pwqs aligned to 256 bytes and allows 15 workqueue
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* flush colors.
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*/
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WORK_STRUCT_FLAG_BITS = WORK_STRUCT_COLOR_SHIFT +
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WORK_STRUCT_COLOR_BITS,
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/* data contains off-queue information when !WORK_STRUCT_PWQ */
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WORK_OFFQ_FLAG_BASE = WORK_STRUCT_COLOR_SHIFT,
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__WORK_OFFQ_CANCELING = WORK_OFFQ_FLAG_BASE,
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WORK_OFFQ_CANCELING = (1 << __WORK_OFFQ_CANCELING),
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/*
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* When a work item is off queue, its high bits point to the last
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* pool it was on. Cap at 31 bits and use the highest number to
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* indicate that no pool is associated.
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*/
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WORK_OFFQ_FLAG_BITS = 1,
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WORK_OFFQ_POOL_SHIFT = WORK_OFFQ_FLAG_BASE + WORK_OFFQ_FLAG_BITS,
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WORK_OFFQ_LEFT = BITS_PER_LONG - WORK_OFFQ_POOL_SHIFT,
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WORK_OFFQ_POOL_BITS = WORK_OFFQ_LEFT <= 31 ? WORK_OFFQ_LEFT : 31,
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WORK_OFFQ_POOL_NONE = (1LU << WORK_OFFQ_POOL_BITS) - 1,
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/* convenience constants */
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WORK_STRUCT_FLAG_MASK = (1UL << WORK_STRUCT_FLAG_BITS) - 1,
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WORK_STRUCT_WQ_DATA_MASK = ~WORK_STRUCT_FLAG_MASK,
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WORK_STRUCT_NO_POOL = (unsigned long)WORK_OFFQ_POOL_NONE << WORK_OFFQ_POOL_SHIFT,
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/* bit mask for work_busy() return values */
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WORK_BUSY_PENDING = 1 << 0,
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WORK_BUSY_RUNNING = 1 << 1,
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/* maximum string length for set_worker_desc() */
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WORKER_DESC_LEN = 24,
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};
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struct work_struct {
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struct list_head entry;
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struct workqueue_struct *data;
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work_func_t func;
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#ifdef CONFIG_LOCKDEP
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struct lockdep_map lockdep_map;
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#endif
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};
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#define WORK_DATA_INIT() ATOMIC_LONG_INIT(WORK_STRUCT_NO_POOL)
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#define WORK_DATA_STATIC_INIT() \
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ATOMIC_LONG_INIT(WORK_STRUCT_NO_POOL | WORK_STRUCT_STATIC)
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struct delayed_work {
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struct work_struct work;
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unsigned int delay;
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/* target workqueue and CPU ->timer uses to queue ->work */
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struct workqueue_struct *wq;
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int cpu;
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};
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static inline struct delayed_work *to_delayed_work(struct work_struct *work)
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{
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return container_of(work, struct delayed_work, work);
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}
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struct execute_work {
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struct work_struct work;
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};
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struct workqueue_struct {
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spinlock_t lock;
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struct list_head worklist;
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struct list_head delayed_worklist;
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};
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/*
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* Workqueue flags and constants. For details, please refer to
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* Documentation/workqueue.txt.
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*/
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enum {
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WQ_UNBOUND = 1 << 1, /* not bound to any cpu */
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WQ_FREEZABLE = 1 << 2, /* freeze during suspend */
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WQ_MEM_RECLAIM = 1 << 3, /* may be used for memory reclaim */
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WQ_HIGHPRI = 1 << 4, /* high priority */
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WQ_CPU_INTENSIVE = 1 << 5, /* cpu intensive workqueue */
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WQ_SYSFS = 1 << 6, /* visible in sysfs, see wq_sysfs_register() */
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/*
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* Per-cpu workqueues are generally preferred because they tend to
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* show better performance thanks to cache locality. Per-cpu
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* workqueues exclude the scheduler from choosing the CPU to
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* execute the worker threads, which has an unfortunate side effect
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* of increasing power consumption.
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*
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* The scheduler considers a CPU idle if it doesn't have any task
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* to execute and tries to keep idle cores idle to conserve power;
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* however, for example, a per-cpu work item scheduled from an
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* interrupt handler on an idle CPU will force the scheduler to
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* excute the work item on that CPU breaking the idleness, which in
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* turn may lead to more scheduling choices which are sub-optimal
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* in terms of power consumption.
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*
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* Workqueues marked with WQ_POWER_EFFICIENT are per-cpu by default
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* but become unbound if workqueue.power_efficient kernel param is
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* specified. Per-cpu workqueues which are identified to
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* contribute significantly to power-consumption are identified and
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* marked with this flag and enabling the power_efficient mode
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* leads to noticeable power saving at the cost of small
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* performance disadvantage.
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*
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* http://thread.gmane.org/gmane.linux.kernel/1480396
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*/
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WQ_POWER_EFFICIENT = 1 << 7,
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__WQ_DRAINING = 1 << 16, /* internal: workqueue is draining */
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__WQ_ORDERED = 1 << 17, /* internal: workqueue is ordered */
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WQ_MAX_ACTIVE = 512, /* I like 512, better ideas? */
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WQ_MAX_UNBOUND_PER_CPU = 4, /* 4 * #cpus for unbound wq */
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WQ_DFL_ACTIVE = WQ_MAX_ACTIVE / 2,
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};
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/* unbound wq's aren't per-cpu, scale max_active according to #cpus */
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#define WQ_UNBOUND_MAX_ACTIVE \
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max_t(int, WQ_MAX_ACTIVE, num_possible_cpus() * WQ_MAX_UNBOUND_PER_CPU)
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/*
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* System-wide workqueues which are always present.
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*
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* system_wq is the one used by schedule[_delayed]_work[_on]().
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* Multi-CPU multi-threaded. There are users which expect relatively
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* short queue flush time. Don't queue works which can run for too
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* long.
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*
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* system_highpri_wq is similar to system_wq but for work items which
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* require WQ_HIGHPRI.
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*
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* system_long_wq is similar to system_wq but may host long running
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* works. Queue flushing might take relatively long.
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*
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* system_unbound_wq is unbound workqueue. Workers are not bound to
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* any specific CPU, not concurrency managed, and all queued works are
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* executed immediately as long as max_active limit is not reached and
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* resources are available.
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*
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* system_freezable_wq is equivalent to system_wq except that it's
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* freezable.
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*
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* *_power_efficient_wq are inclined towards saving power and converted
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* into WQ_UNBOUND variants if 'wq_power_efficient' is enabled; otherwise,
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* they are same as their non-power-efficient counterparts - e.g.
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* system_power_efficient_wq is identical to system_wq if
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* 'wq_power_efficient' is disabled. See WQ_POWER_EFFICIENT for more info.
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*/
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extern struct workqueue_struct *system_wq;
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void run_workqueue(struct workqueue_struct *cwq);
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struct workqueue_struct *alloc_workqueue_key(const char *fmt,
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unsigned int flags, int max_active);
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struct workqueue_struct *alloc_workqueue(const char *fmt,
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unsigned int flags,
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int max_active);
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/**
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* alloc_ordered_workqueue - allocate an ordered workqueue
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* @fmt: printf format for the name of the workqueue
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* @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful)
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* @args...: args for @fmt
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*
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* Allocate an ordered workqueue. An ordered workqueue executes at
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* most one work item at any given time in the queued order. They are
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* implemented as unbound workqueues with @max_active of one.
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*
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* RETURNS:
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* Pointer to the allocated workqueue on success, %NULL on failure.
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*/
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#define alloc_ordered_workqueue(fmt, flags, args...) \
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alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED | (flags), 1, ##args)
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bool queue_work(struct workqueue_struct *wq, struct work_struct *work);
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int queue_delayed_work(struct workqueue_struct *wq,
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struct delayed_work *dwork, unsigned long delay);
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bool schedule_delayed_work(struct delayed_work *dwork, unsigned long delay);
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#define INIT_WORK(_work, _func) \
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do { \
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INIT_LIST_HEAD(&(_work)->entry); \
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(_work)->func = _func; \
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} while (0)
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#define INIT_DELAYED_WORK(_work, _func) \
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do { \
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INIT_LIST_HEAD(&(_work)->work.entry); \
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(_work)->work.func = _func; \
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} while (0)
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static inline bool schedule_work(struct work_struct *work)
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{
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return queue_work(system_wq, work);
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}
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#endif /* _LINUX_WORKQUEUE_H */
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