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.
11 * See Documentation/slow-work.txt
14 #ifndef _LINUX_SLOW_WORK_H
15 #define _LINUX_SLOW_WORK_H
17 #ifdef CONFIG_SLOW_WORK
19 #include <linux/sysctl.h>
20 #include <linux/timer.h>
23 #ifdef CONFIG_SLOW_WORK_PROC
28 * The operations used to support slow work items
30 struct slow_work_ops
{
34 /* get a ref on a work item
35 * - return 0 if successful, -ve if not
37 int (*get_ref
)(struct slow_work
*work
);
39 /* discard a ref to a work item */
40 void (*put_ref
)(struct slow_work
*work
);
42 /* execute a work item */
43 void (*execute
)(struct slow_work
*work
);
45 #ifdef CONFIG_SLOW_WORK_PROC
46 /* describe a work item for /proc */
47 void (*desc
)(struct slow_work
*work
, struct seq_file
*m
);
53 * - A reference is held on the parent object by the thread pool when it is
57 struct module
*owner
; /* the owning module */
59 #define SLOW_WORK_PENDING 0 /* item pending (further) execution */
60 #define SLOW_WORK_EXECUTING 1 /* item currently executing */
61 #define SLOW_WORK_ENQ_DEFERRED 2 /* item enqueue deferred */
62 #define SLOW_WORK_VERY_SLOW 3 /* item is very slow */
63 #define SLOW_WORK_CANCELLING 4 /* item is being cancelled, don't enqueue */
64 #define SLOW_WORK_DELAYED 5 /* item is struct delayed_slow_work with active timer */
65 const struct slow_work_ops
*ops
; /* operations table for this item */
66 struct list_head link
; /* link in queue */
67 #ifdef CONFIG_SLOW_WORK_PROC
68 struct timespec mark
; /* jiffies at which queued or exec begun */
72 struct delayed_slow_work
{
73 struct slow_work work
;
74 struct timer_list timer
;
78 * slow_work_init - Initialise a slow work item
79 * @work: The work item to initialise
80 * @ops: The operations to use to handle the slow work item
82 * Initialise a slow work item.
84 static inline void slow_work_init(struct slow_work
*work
,
85 const struct slow_work_ops
*ops
)
89 INIT_LIST_HEAD(&work
->link
);
93 * slow_work_init - Initialise a delayed slow work item
94 * @work: The work item to initialise
95 * @ops: The operations to use to handle the slow work item
97 * Initialise a delayed slow work item.
99 static inline void delayed_slow_work_init(struct delayed_slow_work
*dwork
,
100 const struct slow_work_ops
*ops
)
102 init_timer(&dwork
->timer
);
103 slow_work_init(&dwork
->work
, ops
);
107 * vslow_work_init - Initialise a very slow work item
108 * @work: The work item to initialise
109 * @ops: The operations to use to handle the slow work item
111 * Initialise a very slow work item. This item will be restricted such that
112 * only a certain number of the pool threads will be able to execute items of
115 static inline void vslow_work_init(struct slow_work
*work
,
116 const struct slow_work_ops
*ops
)
118 work
->flags
= 1 << SLOW_WORK_VERY_SLOW
;
120 INIT_LIST_HEAD(&work
->link
);
123 extern int slow_work_enqueue(struct slow_work
*work
);
124 extern void slow_work_cancel(struct slow_work
*work
);
125 extern int slow_work_register_user(struct module
*owner
);
126 extern void slow_work_unregister_user(struct module
*owner
);
128 extern int delayed_slow_work_enqueue(struct delayed_slow_work
*dwork
,
129 unsigned long delay
);
131 static inline void delayed_slow_work_cancel(struct delayed_slow_work
*dwork
)
133 slow_work_cancel(&dwork
->work
);
137 extern ctl_table slow_work_sysctls
[];
140 #endif /* CONFIG_SLOW_WORK */
141 #endif /* _LINUX_SLOW_WORK_H */