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Diffstat (limited to 'include/linux/slow-work.h')
| -rw-r--r-- | include/linux/slow-work.h | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/include/linux/slow-work.h b/include/linux/slow-work.h new file mode 100644 index 00000000000..13337bf6c3f --- /dev/null +++ b/include/linux/slow-work.h @@ -0,0 +1,163 @@ +/* Worker thread pool for slow items, such as filesystem lookups or mkdirs + * + * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + * + * See Documentation/slow-work.txt + */ + +#ifndef _LINUX_SLOW_WORK_H +#define _LINUX_SLOW_WORK_H + +#ifdef CONFIG_SLOW_WORK + +#include <linux/sysctl.h> +#include <linux/timer.h> + +struct slow_work; +#ifdef CONFIG_SLOW_WORK_DEBUG +struct seq_file; +#endif + +/* + * The operations used to support slow work items + */ +struct slow_work_ops { + /* owner */ + struct module *owner; + + /* get a ref on a work item + * - return 0 if successful, -ve if not + */ + int (*get_ref)(struct slow_work *work); + + /* discard a ref to a work item */ + void (*put_ref)(struct slow_work *work); + + /* execute a work item */ + void (*execute)(struct slow_work *work); + +#ifdef CONFIG_SLOW_WORK_DEBUG + /* describe a work item for debugfs */ + void (*desc)(struct slow_work *work, struct seq_file *m); +#endif +}; + +/* + * A slow work item + * - A reference is held on the parent object by the thread pool when it is + * queued + */ +struct slow_work { + struct module *owner; /* the owning module */ + unsigned long flags; +#define SLOW_WORK_PENDING 0 /* item pending (further) execution */ +#define SLOW_WORK_EXECUTING 1 /* item currently executing */ +#define SLOW_WORK_ENQ_DEFERRED 2 /* item enqueue deferred */ +#define SLOW_WORK_VERY_SLOW 3 /* item is very slow */ +#define SLOW_WORK_CANCELLING 4 /* item is being cancelled, don't enqueue */ +#define SLOW_WORK_DELAYED 5 /* item is struct delayed_slow_work with active timer */ + const struct slow_work_ops *ops; /* operations table for this item */ + struct list_head link; /* link in queue */ +#ifdef CONFIG_SLOW_WORK_DEBUG + struct timespec mark; /* jiffies at which queued or exec begun */ +#endif +}; + +struct delayed_slow_work { + struct slow_work work; + struct timer_list timer; +}; + +/** + * slow_work_init - Initialise a slow work item + * @work: The work item to initialise + * @ops: The operations to use to handle the slow work item + * + * Initialise a slow work item. + */ +static inline void slow_work_init(struct slow_work *work, + const struct slow_work_ops *ops) +{ + work->flags = 0; + work->ops = ops; + INIT_LIST_HEAD(&work->link); +} + +/** + * slow_work_init - Initialise a delayed slow work item + * @work: The work item to initialise + * @ops: The operations to use to handle the slow work item + * + * Initialise a delayed slow work item. + */ +static inline void delayed_slow_work_init(struct delayed_slow_work *dwork, + const struct slow_work_ops *ops) +{ + init_timer(&dwork->timer); + slow_work_init(&dwork->work, ops); +} + +/** + * vslow_work_init - Initialise a very slow work item + * @work: The work item to initialise + * @ops: The operations to use to handle the slow work item + * + * Initialise a very slow work item. This item will be restricted such that + * only a certain number of the pool threads will be able to execute items of + * this type. + */ +static inline void vslow_work_init(struct slow_work *work, + const struct slow_work_ops *ops) +{ + work->flags = 1 << SLOW_WORK_VERY_SLOW; + work->ops = ops; + INIT_LIST_HEAD(&work->link); +} + +/** + * slow_work_is_queued - Determine if a slow work item is on the work queue + * work: The work item to test + * + * Determine if the specified slow-work item is on the work queue. This + * returns true if it is actually on the queue. + * + * If the item is executing and has been marked for requeue when execution + * finishes, then false will be returned. + * + * Anyone wishing to wait for completion of execution can wait on the + * SLOW_WORK_EXECUTING bit. + */ +static inline bool slow_work_is_queued(struct slow_work *work) +{ + unsigned long flags = work->flags; + return flags & SLOW_WORK_PENDING && !(flags & SLOW_WORK_EXECUTING); +} + +extern int slow_work_enqueue(struct slow_work *work); +extern void slow_work_cancel(struct slow_work *work); +extern int slow_work_register_user(struct module *owner); +extern void slow_work_unregister_user(struct module *owner); + +extern int delayed_slow_work_enqueue(struct delayed_slow_work *dwork, + unsigned long delay); + +static inline void delayed_slow_work_cancel(struct delayed_slow_work *dwork) +{ + slow_work_cancel(&dwork->work); +} + +extern bool slow_work_sleep_till_thread_needed(struct slow_work *work, + signed long *_timeout); + +#ifdef CONFIG_SYSCTL +extern ctl_table slow_work_sysctls[]; +#endif + +#endif /* CONFIG_SLOW_WORK */ +#endif /* _LINUX_SLOW_WORK_H */ |