2 * Copyright (C) 2007 Oracle. All rights reserved.
3 * Copyright (C) 2014 Fujitsu. All rights reserved.
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public
7 * License v2 as published by the Free Software Foundation.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
14 * You should have received a copy of the GNU General Public
15 * License along with this program; if not, write to the
16 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 * Boston, MA 021110-1307, USA.
20 #include <linux/kthread.h>
21 #include <linux/slab.h>
22 #include <linux/list.h>
23 #include <linux/spinlock.h>
24 #include <linux/freezer.h>
25 #include "async-thread.h"
28 #define WORK_DONE_BIT 0
29 #define WORK_ORDER_DONE_BIT 1
30 #define WORK_HIGH_PRIO_BIT 2
32 #define NO_THRESHOLD (-1)
33 #define DFT_THRESHOLD (32)
35 struct __btrfs_workqueue {
36 struct workqueue_struct *normal_wq;
37 /* List head pointing to ordered work list */
38 struct list_head ordered_list;
40 /* Spinlock for ordered_list */
43 /* Thresholding related variants */
49 spinlock_t thres_lock;
52 struct btrfs_workqueue {
53 struct __btrfs_workqueue *normal;
54 struct __btrfs_workqueue *high;
57 static void normal_work_helper(struct btrfs_work *work);
59 #define BTRFS_WORK_HELPER(name) \
60 void btrfs_##name(struct work_struct *arg) \
62 struct btrfs_work *work = container_of(arg, struct btrfs_work, \
64 normal_work_helper(work); \
67 BTRFS_WORK_HELPER(worker_helper);
68 BTRFS_WORK_HELPER(delalloc_helper);
69 BTRFS_WORK_HELPER(flush_delalloc_helper);
70 BTRFS_WORK_HELPER(cache_helper);
71 BTRFS_WORK_HELPER(submit_helper);
72 BTRFS_WORK_HELPER(fixup_helper);
73 BTRFS_WORK_HELPER(endio_helper);
74 BTRFS_WORK_HELPER(endio_meta_helper);
75 BTRFS_WORK_HELPER(endio_meta_write_helper);
76 BTRFS_WORK_HELPER(endio_raid56_helper);
77 BTRFS_WORK_HELPER(rmw_helper);
78 BTRFS_WORK_HELPER(endio_write_helper);
79 BTRFS_WORK_HELPER(freespace_write_helper);
80 BTRFS_WORK_HELPER(delayed_meta_helper);
81 BTRFS_WORK_HELPER(readahead_helper);
82 BTRFS_WORK_HELPER(qgroup_rescan_helper);
83 BTRFS_WORK_HELPER(extent_refs_helper);
84 BTRFS_WORK_HELPER(scrub_helper);
85 BTRFS_WORK_HELPER(scrubwrc_helper);
86 BTRFS_WORK_HELPER(scrubnc_helper);
88 static struct __btrfs_workqueue *
89 __btrfs_alloc_workqueue(const char *name, int flags, int max_active,
92 struct __btrfs_workqueue *ret = kzalloc(sizeof(*ret), GFP_NOFS);
97 ret->max_active = max_active;
98 atomic_set(&ret->pending, 0);
100 thresh = DFT_THRESHOLD;
101 /* For low threshold, disabling threshold is a better choice */
102 if (thresh < DFT_THRESHOLD) {
103 ret->current_max = max_active;
104 ret->thresh = NO_THRESHOLD;
106 ret->current_max = 1;
107 ret->thresh = thresh;
110 if (flags & WQ_HIGHPRI)
111 ret->normal_wq = alloc_workqueue("%s-%s-high", flags,
115 ret->normal_wq = alloc_workqueue("%s-%s", flags,
116 ret->max_active, "btrfs",
118 if (unlikely(!ret->normal_wq)) {
123 INIT_LIST_HEAD(&ret->ordered_list);
124 spin_lock_init(&ret->list_lock);
125 spin_lock_init(&ret->thres_lock);
126 trace_btrfs_workqueue_alloc(ret, name, flags & WQ_HIGHPRI);
131 __btrfs_destroy_workqueue(struct __btrfs_workqueue *wq);
133 struct btrfs_workqueue *btrfs_alloc_workqueue(const char *name,
138 struct btrfs_workqueue *ret = kzalloc(sizeof(*ret), GFP_NOFS);
143 ret->normal = __btrfs_alloc_workqueue(name, flags & ~WQ_HIGHPRI,
145 if (unlikely(!ret->normal)) {
150 if (flags & WQ_HIGHPRI) {
151 ret->high = __btrfs_alloc_workqueue(name, flags, max_active,
153 if (unlikely(!ret->high)) {
154 __btrfs_destroy_workqueue(ret->normal);
163 * Hook for threshold which will be called in btrfs_queue_work.
164 * This hook WILL be called in IRQ handler context,
165 * so workqueue_set_max_active MUST NOT be called in this hook
167 static inline void thresh_queue_hook(struct __btrfs_workqueue *wq)
169 if (wq->thresh == NO_THRESHOLD)
171 atomic_inc(&wq->pending);
175 * Hook for threshold which will be called before executing the work,
176 * This hook is called in kthread content.
177 * So workqueue_set_max_active is called here.
179 static inline void thresh_exec_hook(struct __btrfs_workqueue *wq)
185 if (wq->thresh == NO_THRESHOLD)
188 atomic_dec(&wq->pending);
189 spin_lock(&wq->thres_lock);
191 * Use wq->count to limit the calling frequency of
192 * workqueue_set_max_active.
195 wq->count %= (wq->thresh / 4);
198 new_max_active = wq->current_max;
201 * pending may be changed later, but it's OK since we really
202 * don't need it so accurate to calculate new_max_active.
204 pending = atomic_read(&wq->pending);
205 if (pending > wq->thresh)
207 if (pending < wq->thresh / 2)
209 new_max_active = clamp_val(new_max_active, 1, wq->max_active);
210 if (new_max_active != wq->current_max) {
212 wq->current_max = new_max_active;
215 spin_unlock(&wq->thres_lock);
218 workqueue_set_max_active(wq->normal_wq, wq->current_max);
222 static void run_ordered_work(struct __btrfs_workqueue *wq)
224 struct list_head *list = &wq->ordered_list;
225 struct btrfs_work *work;
226 spinlock_t *lock = &wq->list_lock;
230 spin_lock_irqsave(lock, flags);
231 if (list_empty(list))
233 work = list_entry(list->next, struct btrfs_work,
235 if (!test_bit(WORK_DONE_BIT, &work->flags))
239 * we are going to call the ordered done function, but
240 * we leave the work item on the list as a barrier so
241 * that later work items that are done don't have their
242 * functions called before this one returns
244 if (test_and_set_bit(WORK_ORDER_DONE_BIT, &work->flags))
246 trace_btrfs_ordered_sched(work);
247 spin_unlock_irqrestore(lock, flags);
248 work->ordered_func(work);
250 /* now take the lock again and drop our item from the list */
251 spin_lock_irqsave(lock, flags);
252 list_del(&work->ordered_list);
253 spin_unlock_irqrestore(lock, flags);
256 * we don't want to call the ordered free functions
257 * with the lock held though
259 work->ordered_free(work);
260 trace_btrfs_all_work_done(work);
262 spin_unlock_irqrestore(lock, flags);
265 static void normal_work_helper(struct btrfs_work *work)
267 struct __btrfs_workqueue *wq;
271 * We should not touch things inside work in the following cases:
272 * 1) after work->func() if it has no ordered_free
273 * Since the struct is freed in work->func().
274 * 2) after setting WORK_DONE_BIT
275 * The work may be freed in other threads almost instantly.
276 * So we save the needed things here.
278 if (work->ordered_func)
282 trace_btrfs_work_sched(work);
283 thresh_exec_hook(wq);
286 set_bit(WORK_DONE_BIT, &work->flags);
287 run_ordered_work(wq);
290 trace_btrfs_all_work_done(work);
293 void btrfs_init_work(struct btrfs_work *work, btrfs_work_func_t uniq_func,
295 btrfs_func_t ordered_func,
296 btrfs_func_t ordered_free)
299 work->ordered_func = ordered_func;
300 work->ordered_free = ordered_free;
301 INIT_WORK(&work->normal_work, uniq_func);
302 INIT_LIST_HEAD(&work->ordered_list);
306 static inline void __btrfs_queue_work(struct __btrfs_workqueue *wq,
307 struct btrfs_work *work)
312 thresh_queue_hook(wq);
313 if (work->ordered_func) {
314 spin_lock_irqsave(&wq->list_lock, flags);
315 list_add_tail(&work->ordered_list, &wq->ordered_list);
316 spin_unlock_irqrestore(&wq->list_lock, flags);
318 queue_work(wq->normal_wq, &work->normal_work);
319 trace_btrfs_work_queued(work);
322 void btrfs_queue_work(struct btrfs_workqueue *wq,
323 struct btrfs_work *work)
325 struct __btrfs_workqueue *dest_wq;
327 if (test_bit(WORK_HIGH_PRIO_BIT, &work->flags) && wq->high)
330 dest_wq = wq->normal;
331 __btrfs_queue_work(dest_wq, work);
335 __btrfs_destroy_workqueue(struct __btrfs_workqueue *wq)
337 destroy_workqueue(wq->normal_wq);
338 trace_btrfs_workqueue_destroy(wq);
342 void btrfs_destroy_workqueue(struct btrfs_workqueue *wq)
347 __btrfs_destroy_workqueue(wq->high);
348 __btrfs_destroy_workqueue(wq->normal);
352 void btrfs_workqueue_set_max(struct btrfs_workqueue *wq, int max)
356 wq->normal->max_active = max;
358 wq->high->max_active = max;
361 void btrfs_set_work_high_priority(struct btrfs_work *work)
363 set_bit(WORK_HIGH_PRIO_BIT, &work->flags);