1 /* Worker thread pool for slow items, such as filesystem lookups or mkdirs
3 * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public Licence
8 * as published by the Free Software Foundation; either version
9 * 2 of the Licence, or (at your option) any later version.
12 #ifndef _LINUX_SLOW_WORK_H
13 #define _LINUX_SLOW_WORK_H
15 #ifdef CONFIG_SLOW_WORK
20 * The operations used to support slow work items
22 struct slow_work_ops {
23 /* get a ref on a work item
24 * - return 0 if successful, -ve if not
26 int (*get_ref)(struct slow_work *work);
28 /* discard a ref to a work item */
29 void (*put_ref)(struct slow_work *work);
31 /* execute a work item */
32 void (*execute)(struct slow_work *work);
37 * - A reference is held on the parent object by the thread pool when it is
42 #define SLOW_WORK_PENDING 0 /* item pending (further) execution */
43 #define SLOW_WORK_EXECUTING 1 /* item currently executing */
44 #define SLOW_WORK_ENQ_DEFERRED 2 /* item enqueue deferred */
45 #define SLOW_WORK_VERY_SLOW 3 /* item is very slow */
46 const struct slow_work_ops *ops; /* operations table for this item */
47 struct list_head link; /* link in queue */
51 * slow_work_init - Initialise a slow work item
52 * @work: The work item to initialise
53 * @ops: The operations to use to handle the slow work item
55 * Initialise a slow work item.
57 static inline void slow_work_init(struct slow_work *work,
58 const struct slow_work_ops *ops)
62 INIT_LIST_HEAD(&work->link);
66 * slow_work_init - Initialise a very slow work item
67 * @work: The work item to initialise
68 * @ops: The operations to use to handle the slow work item
70 * Initialise a very slow work item. This item will be restricted such that
71 * only a certain number of the pool threads will be able to execute items of
74 static inline void vslow_work_init(struct slow_work *work,
75 const struct slow_work_ops *ops)
77 work->flags = 1 << SLOW_WORK_VERY_SLOW;
79 INIT_LIST_HEAD(&work->link);
82 extern int slow_work_enqueue(struct slow_work *work);
83 extern int slow_work_register_user(void);
84 extern void slow_work_unregister_user(void);
87 #endif /* CONFIG_SLOW_WORK */
88 #endif /* _LINUX_SLOW_WORK_H */