164 строки
4.6 KiB
C
164 строки
4.6 KiB
C
/* Worker thread pool for slow items, such as filesystem lookups or mkdirs
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*
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* Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public Licence
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* as published by the Free Software Foundation; either version
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* 2 of the Licence, or (at your option) any later version.
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*
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* See Documentation/slow-work.txt
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*/
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#ifndef _LINUX_SLOW_WORK_H
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#define _LINUX_SLOW_WORK_H
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#ifdef CONFIG_SLOW_WORK
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#include <linux/sysctl.h>
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#include <linux/timer.h>
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struct slow_work;
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#ifdef CONFIG_SLOW_WORK_DEBUG
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struct seq_file;
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#endif
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/*
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* The operations used to support slow work items
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*/
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struct slow_work_ops {
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/* owner */
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struct module *owner;
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/* get a ref on a work item
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* - return 0 if successful, -ve if not
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*/
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int (*get_ref)(struct slow_work *work);
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/* discard a ref to a work item */
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void (*put_ref)(struct slow_work *work);
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/* execute a work item */
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void (*execute)(struct slow_work *work);
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#ifdef CONFIG_SLOW_WORK_DEBUG
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/* describe a work item for debugfs */
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void (*desc)(struct slow_work *work, struct seq_file *m);
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#endif
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};
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/*
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* A slow work item
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* - A reference is held on the parent object by the thread pool when it is
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* queued
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*/
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struct slow_work {
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struct module *owner; /* the owning module */
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unsigned long flags;
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#define SLOW_WORK_PENDING 0 /* item pending (further) execution */
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#define SLOW_WORK_EXECUTING 1 /* item currently executing */
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#define SLOW_WORK_ENQ_DEFERRED 2 /* item enqueue deferred */
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#define SLOW_WORK_VERY_SLOW 3 /* item is very slow */
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#define SLOW_WORK_CANCELLING 4 /* item is being cancelled, don't enqueue */
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#define SLOW_WORK_DELAYED 5 /* item is struct delayed_slow_work with active timer */
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const struct slow_work_ops *ops; /* operations table for this item */
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struct list_head link; /* link in queue */
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#ifdef CONFIG_SLOW_WORK_DEBUG
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struct timespec mark; /* jiffies at which queued or exec begun */
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#endif
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};
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struct delayed_slow_work {
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struct slow_work work;
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struct timer_list timer;
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};
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/**
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* slow_work_init - Initialise a slow work item
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* @work: The work item to initialise
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* @ops: The operations to use to handle the slow work item
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*
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* Initialise a slow work item.
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*/
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static inline void slow_work_init(struct slow_work *work,
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const struct slow_work_ops *ops)
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{
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work->flags = 0;
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work->ops = ops;
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INIT_LIST_HEAD(&work->link);
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}
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/**
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* slow_work_init - Initialise a delayed slow work item
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* @work: The work item to initialise
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* @ops: The operations to use to handle the slow work item
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*
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* Initialise a delayed slow work item.
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*/
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static inline void delayed_slow_work_init(struct delayed_slow_work *dwork,
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const struct slow_work_ops *ops)
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{
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init_timer(&dwork->timer);
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slow_work_init(&dwork->work, ops);
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}
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/**
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* vslow_work_init - Initialise a very slow work item
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* @work: The work item to initialise
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* @ops: The operations to use to handle the slow work item
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*
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* Initialise a very slow work item. This item will be restricted such that
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* only a certain number of the pool threads will be able to execute items of
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* this type.
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*/
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static inline void vslow_work_init(struct slow_work *work,
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const struct slow_work_ops *ops)
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{
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work->flags = 1 << SLOW_WORK_VERY_SLOW;
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work->ops = ops;
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INIT_LIST_HEAD(&work->link);
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}
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/**
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* slow_work_is_queued - Determine if a slow work item is on the work queue
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* work: The work item to test
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*
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* Determine if the specified slow-work item is on the work queue. This
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* returns true if it is actually on the queue.
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*
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* If the item is executing and has been marked for requeue when execution
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* finishes, then false will be returned.
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*
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* Anyone wishing to wait for completion of execution can wait on the
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* SLOW_WORK_EXECUTING bit.
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*/
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static inline bool slow_work_is_queued(struct slow_work *work)
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{
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unsigned long flags = work->flags;
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return flags & SLOW_WORK_PENDING && !(flags & SLOW_WORK_EXECUTING);
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}
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extern int slow_work_enqueue(struct slow_work *work);
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extern void slow_work_cancel(struct slow_work *work);
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extern int slow_work_register_user(struct module *owner);
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extern void slow_work_unregister_user(struct module *owner);
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extern int delayed_slow_work_enqueue(struct delayed_slow_work *dwork,
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unsigned long delay);
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static inline void delayed_slow_work_cancel(struct delayed_slow_work *dwork)
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{
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slow_work_cancel(&dwork->work);
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}
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extern bool slow_work_sleep_till_thread_needed(struct slow_work *work,
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signed long *_timeout);
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#ifdef CONFIG_SYSCTL
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extern ctl_table slow_work_sysctls[];
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#endif
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#endif /* CONFIG_SLOW_WORK */
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#endif /* _LINUX_SLOW_WORK_H */
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