Commit | Line | Data |
---|---|---|
8b712842 CM |
1 | /* |
2 | * Copyright (C) 2007 Oracle. All rights reserved. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public | |
6 | * License v2 as published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, | |
9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
11 | * General Public License for more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public | |
14 | * License along with this program; if not, write to the | |
15 | * Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
16 | * Boston, MA 021110-1307, USA. | |
17 | */ | |
18 | ||
19 | #ifndef __BTRFS_ASYNC_THREAD_ | |
20 | #define __BTRFS_ASYNC_THREAD_ | |
21 | ||
22 | struct btrfs_worker_thread; | |
23 | ||
24 | /* | |
25 | * This is similar to a workqueue, but it is meant to spread the operations | |
26 | * across all available cpus instead of just the CPU that was used to | |
27 | * queue the work. There is also some batching introduced to try and | |
28 | * cut down on context switches. | |
29 | * | |
30 | * By default threads are added on demand up to 2 * the number of cpus. | |
31 | * Changing struct btrfs_workers->max_workers is one way to prevent | |
32 | * demand creation of kthreads. | |
33 | * | |
34 | * the basic model of these worker threads is to embed a btrfs_work | |
35 | * structure in your own data struct, and use container_of in a | |
36 | * work function to get back to your data struct. | |
37 | */ | |
38 | struct btrfs_work { | |
39 | /* | |
4a69a410 | 40 | * func should be set to the function you want called |
8b712842 | 41 | * your work struct is passed as the only arg |
4a69a410 CM |
42 | * |
43 | * ordered_func must be set for work sent to an ordered work queue, | |
44 | * and it is called to complete a given work item in the same | |
45 | * order they were sent to the queue. | |
8b712842 CM |
46 | */ |
47 | void (*func)(struct btrfs_work *work); | |
4a69a410 CM |
48 | void (*ordered_func)(struct btrfs_work *work); |
49 | void (*ordered_free)(struct btrfs_work *work); | |
8b712842 CM |
50 | |
51 | /* | |
52 | * flags should be set to zero. It is used to make sure the | |
53 | * struct is only inserted once into the list. | |
54 | */ | |
55 | unsigned long flags; | |
56 | ||
57 | /* don't touch these */ | |
58 | struct btrfs_worker_thread *worker; | |
59 | struct list_head list; | |
4a69a410 | 60 | struct list_head order_list; |
8b712842 CM |
61 | }; |
62 | ||
63 | struct btrfs_workers { | |
64 | /* current number of running workers */ | |
65 | int num_workers; | |
66 | ||
61d92c32 CM |
67 | int num_workers_starting; |
68 | ||
8b712842 CM |
69 | /* max number of workers allowed. changed by btrfs_start_workers */ |
70 | int max_workers; | |
71 | ||
35d8ba66 CM |
72 | /* once a worker has this many requests or fewer, it is idle */ |
73 | int idle_thresh; | |
74 | ||
4a69a410 CM |
75 | /* force completions in the order they were queued */ |
76 | int ordered; | |
77 | ||
9042846b CM |
78 | /* more workers required, but in an interrupt handler */ |
79 | int atomic_start_pending; | |
80 | ||
81 | /* | |
82 | * are we allowed to sleep while starting workers or are we required | |
61d92c32 CM |
83 | * to start them at a later time? If we can't sleep, this indicates |
84 | * which queue we need to use to schedule thread creation. | |
9042846b | 85 | */ |
61d92c32 | 86 | struct btrfs_workers *atomic_worker_start; |
9042846b | 87 | |
d352ac68 CM |
88 | /* list with all the work threads. The workers on the idle thread |
89 | * may be actively servicing jobs, but they haven't yet hit the | |
90 | * idle thresh limit above. | |
91 | */ | |
8b712842 | 92 | struct list_head worker_list; |
35d8ba66 | 93 | struct list_head idle_list; |
8b712842 | 94 | |
4a69a410 CM |
95 | /* |
96 | * when operating in ordered mode, this maintains the list | |
97 | * of work items waiting for completion | |
98 | */ | |
99 | struct list_head order_list; | |
d313d7a3 | 100 | struct list_head prio_order_list; |
4a69a410 | 101 | |
8b712842 CM |
102 | /* lock for finding the next worker thread to queue on */ |
103 | spinlock_t lock; | |
5443be45 | 104 | |
4e3f9c50 CM |
105 | /* lock for the ordered lists */ |
106 | spinlock_t order_lock; | |
107 | ||
d352ac68 | 108 | /* extra name for this worker, used for current->name */ |
5443be45 | 109 | char *name; |
8b712842 CM |
110 | }; |
111 | ||
0dc3b84a JB |
112 | void btrfs_queue_worker(struct btrfs_workers *workers, struct btrfs_work *work); |
113 | int btrfs_start_workers(struct btrfs_workers *workers); | |
8b712842 | 114 | int btrfs_stop_workers(struct btrfs_workers *workers); |
61d92c32 CM |
115 | void btrfs_init_workers(struct btrfs_workers *workers, char *name, int max, |
116 | struct btrfs_workers *async_starter); | |
8b712842 | 117 | int btrfs_requeue_work(struct btrfs_work *work); |
d313d7a3 | 118 | void btrfs_set_work_high_prio(struct btrfs_work *work); |
8b712842 | 119 | #endif |