/* * The first word is the work queue pointer and the flags rolled into * one
*/ #define work_data_bits(work) ((unsignedlong *)(&(work)->data))
enum work_bits {
WORK_STRUCT_PENDING_BIT = 0, /* work item is pending execution */
WORK_STRUCT_INACTIVE_BIT, /* work item is inactive */
WORK_STRUCT_PWQ_BIT, /* data points to pwq */
WORK_STRUCT_LINKED_BIT, /* next work is linked to this one */ #ifdef CONFIG_DEBUG_OBJECTS_WORK
WORK_STRUCT_STATIC_BIT, /* static initializer (debugobjects) */ #endif
WORK_STRUCT_FLAG_BITS,
/* color for workqueue flushing */
WORK_STRUCT_COLOR_SHIFT = WORK_STRUCT_FLAG_BITS,
WORK_STRUCT_COLOR_BITS = 4,
/* * When WORK_STRUCT_PWQ is set, reserve 8 bits off of pwq pointer w/ * debugobjects turned off. This makes pwqs aligned to 256 bytes (512 * bytes w/ DEBUG_OBJECTS_WORK) and allows 16 workqueue flush colors. * * MSB * [ pwq pointer ] [ flush color ] [ STRUCT flags ] * 4 bits 4 or 5 bits
*/
WORK_STRUCT_PWQ_SHIFT = WORK_STRUCT_COLOR_SHIFT + WORK_STRUCT_COLOR_BITS,
/* * data contains off-queue information when !WORK_STRUCT_PWQ. * * MSB * [ pool ID ] [ disable depth ] [ OFFQ flags ] [ STRUCT flags ] * 16 bits 1 bit 4 or 5 bits
*/
WORK_OFFQ_FLAG_SHIFT = WORK_STRUCT_FLAG_BITS,
WORK_OFFQ_BH_BIT = WORK_OFFQ_FLAG_SHIFT,
WORK_OFFQ_FLAG_END,
WORK_OFFQ_FLAG_BITS = WORK_OFFQ_FLAG_END - WORK_OFFQ_FLAG_SHIFT,
/* * When a work item is off queue, the high bits encode off-queue flags * and the last pool it was on. Cap pool ID to 31 bits and use the * highest number to indicate that no pool is associated.
*/
WORK_OFFQ_POOL_SHIFT = WORK_OFFQ_DISABLE_SHIFT + WORK_OFFQ_DISABLE_BITS,
WORK_OFFQ_LEFT = BITS_PER_LONG - WORK_OFFQ_POOL_SHIFT,
WORK_OFFQ_POOL_BITS = WORK_OFFQ_LEFT <= 31 ? WORK_OFFQ_LEFT : 31,
};
enum wq_affn_scope {
WQ_AFFN_DFL, /* use system default */
WQ_AFFN_CPU, /* one pod per CPU */
WQ_AFFN_SMT, /* one pod poer SMT */
WQ_AFFN_CACHE, /* one pod per LLC */
WQ_AFFN_NUMA, /* one pod per NUMA node */
WQ_AFFN_SYSTEM, /* one pod across the whole system */
WQ_AFFN_NR_TYPES,
};
/** * struct workqueue_attrs - A struct for workqueue attributes. * * This can be used to change attributes of an unbound workqueue.
*/ struct workqueue_attrs { /** * @nice: nice level
*/ int nice;
/** * @cpumask: allowed CPUs * * Work items in this workqueue are affine to these CPUs and not allowed * to execute on other CPUs. A pool serving a workqueue must have the * same @cpumask.
*/
cpumask_var_t cpumask;
/** * @__pod_cpumask: internal attribute used to create per-pod pools * * Internal use only. * * Per-pod unbound worker pools are used to improve locality. Always a * subset of ->cpumask. A workqueue can be associated with multiple * worker pools with disjoint @__pod_cpumask's. Whether the enforcement * of a pool's @__pod_cpumask is strict depends on @affn_strict.
*/
cpumask_var_t __pod_cpumask;
/** * @affn_strict: affinity scope is strict * * If clear, workqueue will make a best-effort attempt at starting the * worker inside @__pod_cpumask but the scheduler is free to migrate it * outside. * * If set, workers are only allowed to run inside @__pod_cpumask.
*/ bool affn_strict;
/* * Below fields aren't properties of a worker_pool. They only modify how * :c:func:`apply_workqueue_attrs` select pools and thus don't * participate in pool hash calculations or equality comparisons. * * If @affn_strict is set, @cpumask isn't a property of a worker_pool * either.
*/
/** * @affn_scope: unbound CPU affinity scope * * CPU pods are used to improve execution locality of unbound work * items. There are multiple pod types, one for each wq_affn_scope, and * every CPU in the system belongs to one pod in every pod type. CPUs * that belong to the same pod share the worker pool. For example, * selecting %WQ_AFFN_NUMA makes the workqueue use a separate worker * pool for each NUMA node.
*/ enum wq_affn_scope affn_scope;
/** * @ordered: work items must be executed one by one in queueing order
*/ bool ordered;
};
#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
/* * 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_KEY(_work, _func, _onstack, _key) \ do { \
__init_work((_work), _onstack); \
(_work)->data = (atomic_long_t) WORK_DATA_INIT(); \
lockdep_init_map(&(_work)->lockdep_map, "(work_completion)"#_work, (_key), 0); \
INIT_LIST_HEAD(&(_work)->entry); \
(_work)->func = (_func); \
} while (0) #else #define __INIT_WORK_KEY(_work, _func, _onstack, _key) \ do { \
__init_work((_work), _onstack); \
(_work)->data = (atomic_long_t) WORK_DATA_INIT(); \
INIT_LIST_HEAD(&(_work)->entry); \
(_work)->func = (_func); \
} while (0) #endif
/** * 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 * @w: The work item in question
*/ #define delayed_work_pending(w) \
work_pending(&(w)->work)
/* * Workqueue flags and constants. For details, please refer to * Documentation/core-api/workqueue.rst.
*/ enum wq_flags {
WQ_BH = 1 << 0, /* execute in bottom half (softirq) context */
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 workqueue_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 * execute 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_PERCPU = 1 << 8, /* bound to a specific cpu */
/* * Per-node default cap on min_active. Unless explicitly set, min_active * is set to min(max_active, WQ_DFL_MIN_ACTIVE). For more details, see * workqueue_struct->min_active definition.
*/
WQ_DFL_MIN_ACTIVE = 8,
};
/* * System-wide workqueues which are always present. * * system_percpu_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_dfl_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. * * system_bh[_highpri]_wq are convenience interface to softirq. BH work items * are executed in the queueing CPU's BH context in the queueing order.
*/ externstruct workqueue_struct *system_wq; /* use system_percpu_wq, this will be removed */ externstruct workqueue_struct *system_percpu_wq; externstruct workqueue_struct *system_highpri_wq; externstruct workqueue_struct *system_long_wq; externstruct workqueue_struct *system_unbound_wq; externstruct workqueue_struct *system_dfl_wq; externstruct workqueue_struct *system_freezable_wq; externstruct workqueue_struct *system_power_efficient_wq; externstruct workqueue_struct *system_freezable_power_efficient_wq; externstruct workqueue_struct *system_bh_wq; externstruct workqueue_struct *system_bh_highpri_wq;
/** * 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 for @fmt * * For a per-cpu workqueue, @max_active limits the number of in-flight work * items for each CPU. e.g. @max_active of 1 indicates that each CPU can be * executing at most one work item for the workqueue. * * For unbound workqueues, @max_active limits the number of in-flight work items * for the whole system. e.g. @max_active of 16 indicates that there can be * at most 16 work items executing for the workqueue in the whole system. * * As sharing the same active counter for an unbound workqueue across multiple * NUMA nodes can be expensive, @max_active is distributed to each NUMA node * according to the proportion of the number of online CPUs and enforced * independently. * * Depending on online CPU distribution, a node may end up with per-node * max_active which is significantly lower than @max_active, which can lead to * deadlocks if the per-node concurrency limit is lower than the maximum number * of interdependent work items for the workqueue. * * To guarantee forward progress regardless of online CPU distribution, the * concurrency limit on every node is guaranteed to be equal to or greater than * min_active which is set to min(@max_active, %WQ_DFL_MIN_ACTIVE). This means * that the sum of per-node max_active's may be larger than @max_active. * * For detailed information on %WQ_* flags, please refer to * Documentation/core-api/workqueue.rst. * * RETURNS: * Pointer to the allocated workqueue on success, %NULL on failure.
*/
__printf(1, 4) struct workqueue_struct *
alloc_workqueue_noprof(constchar *fmt, unsignedint flags, int max_active, ...); #define alloc_workqueue(...) alloc_hooks(alloc_workqueue_noprof(__VA_ARGS__))
#ifdef CONFIG_LOCKDEP /** * alloc_workqueue_lockdep_map - allocate a workqueue with user-defined lockdep_map * @fmt: printf format for the name of the workqueue * @flags: WQ_* flags * @max_active: max in-flight work items, 0 for default * @lockdep_map: user-defined lockdep_map * @...: args for @fmt * * Same as alloc_workqueue but with the a user-define lockdep_map. Useful for * workqueues created with the same purpose and to avoid leaking a lockdep_map * on each workqueue creation. * * RETURNS: * Pointer to the allocated workqueue on success, %NULL on failure.
*/
__printf(1, 5) struct workqueue_struct *
alloc_workqueue_lockdep_map(constchar *fmt, unsignedint flags, int max_active, struct lockdep_map *lockdep_map, ...);
/** * alloc_ordered_workqueue_lockdep_map - allocate an ordered workqueue with * user-defined lockdep_map * * @fmt: printf format for the name of the workqueue * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful) * @lockdep_map: user-defined lockdep_map * @args: args for @fmt * * Same as alloc_ordered_workqueue but with the a user-define lockdep_map. * Useful for workqueues created with the same purpose and to avoid leaking a * lockdep_map on each workqueue creation. * * RETURNS: * Pointer to the allocated workqueue on success, %NULL on failure.
*/ #define alloc_ordered_workqueue_lockdep_map(fmt, flags, lockdep_map, args...) \
alloc_hooks(alloc_workqueue_lockdep_map(fmt, WQ_UNBOUND | __WQ_ORDERED | (flags),\
1, lockdep_map, ##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)
/** * 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. * * Memory-ordering properties: If it returns %true, guarantees that all stores * preceding the call to queue_work() in the program order will be visible from * the CPU which will execute @work by the time such work executes, e.g., * * { x is initially 0 } * * CPU0 CPU1 * * WRITE_ONCE(x, 1); [ @work is being executed ] * r0 = queue_work(wq, work); r1 = READ_ONCE(x); * * Forbids: r0 == true && r1 == 0
*/ staticinlinebool 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.
*/ staticinlinebool queue_delayed_work(struct workqueue_struct *wq, struct delayed_work *dwork, unsignedlong 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.
*/ staticinlinebool mod_delayed_work(struct workqueue_struct *wq, struct delayed_work *dwork, unsignedlong 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
*/ staticinlinebool 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. * * Shares the same memory-ordering properties of queue_work(), cf. the * DocBook header of queue_work().
*/ staticinlinebool schedule_work(struct work_struct *work)
{ return queue_work(system_wq, work);
}
/** * enable_and_queue_work - Enable and queue a work item on a specific workqueue * @wq: The target workqueue * @work: The work item to be enabled and queued * * This function combines the operations of enable_work() and queue_work(), * providing a convenient way to enable and queue a work item in a single call. * It invokes enable_work() on @work and then queues it if the disable depth * reached 0. Returns %true if the disable depth reached 0 and @work is queued, * and %false otherwise. * * Note that @work is always queued when disable depth reaches zero. If the * desired behavior is queueing only if certain events took place while @work is * disabled, the user should implement the necessary state tracking and perform * explicit conditional queueing after enable_work().
*/ staticinlinebool enable_and_queue_work(struct workqueue_struct *wq, struct work_struct *work)
{ if (enable_work(work)) {
queue_work(wq, work); returntrue;
} returnfalse;
}
/* * Detect attempt to flush system-wide workqueues at compile time when possible. * Warn attempt to flush system-wide workqueues at runtime. * * See https://lkml.kernel.org/r/49925af7-78a8-a3dd-bce6-cfc02e1a9236@I-love.SAKURA.ne.jp * for reasons and steps for converting system-wide workqueues into local workqueues.
*/ externvoid __warn_flushing_systemwide_wq(void)
__compiletime_warning("Please avoid flushing system-wide workqueues.");
/* Please stop using this function, for this function will be removed in near future. */ #define flush_scheduled_work() \
({ \
__warn_flushing_systemwide_wq(); \
__flush_workqueue(system_wq); \
})
/** * 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.
*/ staticinlinebool schedule_delayed_work_on(int cpu, struct delayed_work *dwork, unsignedlong 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.
*/ staticinlinebool schedule_delayed_work(struct delayed_work *dwork, unsignedlong delay)
{ return queue_delayed_work(system_wq, dwork, delay);
}
#ifndef CONFIG_SMP staticinlinelong work_on_cpu(int cpu, long (*fn)(void *), void *arg)
{ return fn(arg);
} staticinlinelong work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg)
{ return fn(arg);
} #else long work_on_cpu_key(int cpu, long (*fn)(void *), void *arg, struct lock_class_key *key); /* * A new key is defined for each caller to make sure the work * associated with the function doesn't share its locking class.
*/ #define work_on_cpu(_cpu, _fn, _arg) \
({ \ staticstruct lock_class_key __key; \
\
work_on_cpu_key(_cpu, _fn, _arg, &__key); \
})
#ifdef CONFIG_SMP int workqueue_prepare_cpu(unsignedint cpu); int workqueue_online_cpu(unsignedint cpu); int workqueue_offline_cpu(unsignedint cpu); #endif
Die Informationen auf dieser Webseite wurden
nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit,
noch Qualität der bereit gestellten Informationen zugesichert.
Bemerkung:
Die farbliche Syntaxdarstellung ist noch experimentell.
