1/* SPDX-License-Identifier: GPL-2.0 */
 2/*
 3 * Copyright (C) 2007 Oracle.  All rights reserved.
 4 * Copyright (C) 2014 Fujitsu.  All rights reserved.
 5 */
 6
 7#ifndef BTRFS_ASYNC_THREAD_H
 8#define BTRFS_ASYNC_THREAD_H
 9
10#include <linux/workqueue.h>
11
12struct btrfs_fs_info;
13struct btrfs_workqueue;
14/* Internal use only */
15struct __btrfs_workqueue;
16struct btrfs_work;
17typedef void (*btrfs_func_t)(struct btrfs_work *arg);
18typedef void (*btrfs_work_func_t)(struct work_struct *arg);
19
20struct btrfs_work {
21	btrfs_func_t func;
22	btrfs_func_t ordered_func;
23	btrfs_func_t ordered_free;
24
25	/* Don't touch things below */
26	struct work_struct normal_work;
27	struct list_head ordered_list;
28	struct __btrfs_workqueue *wq;
29	unsigned long flags;
30};
31
32#define BTRFS_WORK_HELPER_PROTO(name)					\
33void btrfs_##name(struct work_struct *arg)
34
35BTRFS_WORK_HELPER_PROTO(worker_helper);
36BTRFS_WORK_HELPER_PROTO(delalloc_helper);
37BTRFS_WORK_HELPER_PROTO(flush_delalloc_helper);
38BTRFS_WORK_HELPER_PROTO(cache_helper);
39BTRFS_WORK_HELPER_PROTO(submit_helper);
40BTRFS_WORK_HELPER_PROTO(fixup_helper);
41BTRFS_WORK_HELPER_PROTO(endio_helper);
42BTRFS_WORK_HELPER_PROTO(endio_meta_helper);
43BTRFS_WORK_HELPER_PROTO(endio_meta_write_helper);
44BTRFS_WORK_HELPER_PROTO(endio_raid56_helper);
45BTRFS_WORK_HELPER_PROTO(endio_repair_helper);
46BTRFS_WORK_HELPER_PROTO(rmw_helper);
47BTRFS_WORK_HELPER_PROTO(endio_write_helper);
48BTRFS_WORK_HELPER_PROTO(freespace_write_helper);
49BTRFS_WORK_HELPER_PROTO(delayed_meta_helper);
50BTRFS_WORK_HELPER_PROTO(readahead_helper);
51BTRFS_WORK_HELPER_PROTO(qgroup_rescan_helper);
52BTRFS_WORK_HELPER_PROTO(extent_refs_helper);
53BTRFS_WORK_HELPER_PROTO(scrub_helper);
54BTRFS_WORK_HELPER_PROTO(scrubwrc_helper);
55BTRFS_WORK_HELPER_PROTO(scrubnc_helper);
56BTRFS_WORK_HELPER_PROTO(scrubparity_helper);
57
58
59struct btrfs_workqueue *btrfs_alloc_workqueue(struct btrfs_fs_info *fs_info,
60					      const char *name,
61					      unsigned int flags,
62					      int limit_active,
63					      int thresh);
64void btrfs_init_work(struct btrfs_work *work, btrfs_work_func_t helper,
65		     btrfs_func_t func,
66		     btrfs_func_t ordered_func,
67		     btrfs_func_t ordered_free);
68void btrfs_queue_work(struct btrfs_workqueue *wq,
69		      struct btrfs_work *work);
70void btrfs_destroy_workqueue(struct btrfs_workqueue *wq);
71void btrfs_workqueue_set_max(struct btrfs_workqueue *wq, int max);
72void btrfs_set_work_high_priority(struct btrfs_work *work);
73struct btrfs_fs_info *btrfs_work_owner(const struct btrfs_work *work);
74struct btrfs_fs_info *btrfs_workqueue_owner(const struct __btrfs_workqueue *wq);
75bool btrfs_workqueue_normal_congested(const struct btrfs_workqueue *wq);
76
77#endif

  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
 22struct 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 */
 38struct btrfs_work {
 39	/*
 40	 * func should be set to the function you want called
 41	 * your work struct is passed as the only arg
 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.
 46	 */
 47	void (*func)(struct btrfs_work *work);
 48	void (*ordered_func)(struct btrfs_work *work);
 49	void (*ordered_free)(struct btrfs_work *work);
 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;
 60	struct list_head order_list;
 61};
 62
 63struct btrfs_workers {
 64	/* current number of running workers */
 65	int num_workers;
 66
 67	int num_workers_starting;
 68
 69	/* max number of workers allowed.  changed by btrfs_start_workers */
 70	int max_workers;
 71
 72	/* once a worker has this many requests or fewer, it is idle */
 73	int idle_thresh;
 74
 75	/* force completions in the order they were queued */
 76	int ordered;
 77
 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
 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.
 85	 */
 86	struct btrfs_workers *atomic_worker_start;
 87
 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	 */
 92	struct list_head worker_list;
 93	struct list_head idle_list;
 94
 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;
100	struct list_head prio_order_list;
101
102	/* lock for finding the next worker thread to queue on */
103	spinlock_t lock;
104
105	/* lock for the ordered lists */
106	spinlock_t order_lock;
107
108	/* extra name for this worker, used for current->name */
109	char *name;
110};
111
112int btrfs_queue_worker(struct btrfs_workers *workers, struct btrfs_work *work);
113int btrfs_start_workers(struct btrfs_workers *workers, int num_workers);
114int btrfs_stop_workers(struct btrfs_workers *workers);
115void btrfs_init_workers(struct btrfs_workers *workers, char *name, int max,
116			struct btrfs_workers *async_starter);
117int btrfs_requeue_work(struct btrfs_work *work);
118void btrfs_set_work_high_prio(struct btrfs_work *work);
119#endif