1
2
3
4
5
6
7#include <linux/kthread.h>
8#include <linux/slab.h>
9#include <linux/list.h>
10#include <linux/spinlock.h>
11#include <linux/freezer.h>
12#include "async-thread.h"
13#include "ctree.h"
14
15enum {
16 WORK_DONE_BIT,
17 WORK_ORDER_DONE_BIT,
18 WORK_HIGH_PRIO_BIT,
19};
20
21#define NO_THRESHOLD (-1)
22#define DFT_THRESHOLD (32)
23
24struct __btrfs_workqueue {
25 struct workqueue_struct *normal_wq;
26
27
28 struct btrfs_fs_info *fs_info;
29
30
31 struct list_head ordered_list;
32
33
34 spinlock_t list_lock;
35
36
37 atomic_t pending;
38
39
40 int limit_active;
41
42
43 int current_active;
44
45
46 int thresh;
47 unsigned int count;
48 spinlock_t thres_lock;
49};
50
51struct btrfs_workqueue {
52 struct __btrfs_workqueue *normal;
53 struct __btrfs_workqueue *high;
54};
55
56struct btrfs_fs_info * __pure btrfs_workqueue_owner(const struct __btrfs_workqueue *wq)
57{
58 return wq->fs_info;
59}
60
61struct btrfs_fs_info * __pure btrfs_work_owner(const struct btrfs_work *work)
62{
63 return work->wq->fs_info;
64}
65
66bool btrfs_workqueue_normal_congested(const struct btrfs_workqueue *wq)
67{
68
69
70
71
72
73
74 if (wq->normal->thresh == NO_THRESHOLD)
75 return false;
76
77 return atomic_read(&wq->normal->pending) > wq->normal->thresh * 2;
78}
79
80static struct __btrfs_workqueue *
81__btrfs_alloc_workqueue(struct btrfs_fs_info *fs_info, const char *name,
82 unsigned int flags, int limit_active, int thresh)
83{
84 struct __btrfs_workqueue *ret = kzalloc(sizeof(*ret), GFP_KERNEL);
85
86 if (!ret)
87 return NULL;
88
89 ret->fs_info = fs_info;
90 ret->limit_active = limit_active;
91 atomic_set(&ret->pending, 0);
92 if (thresh == 0)
93 thresh = DFT_THRESHOLD;
94
95 if (thresh < DFT_THRESHOLD) {
96 ret->current_active = limit_active;
97 ret->thresh = NO_THRESHOLD;
98 } else {
99
100
101
102
103
104 ret->current_active = 1;
105 ret->thresh = thresh;
106 }
107
108 if (flags & WQ_HIGHPRI)
109 ret->normal_wq = alloc_workqueue("btrfs-%s-high", flags,
110 ret->current_active, name);
111 else
112 ret->normal_wq = alloc_workqueue("btrfs-%s", flags,
113 ret->current_active, name);
114 if (!ret->normal_wq) {
115 kfree(ret);
116 return NULL;
117 }
118
119 INIT_LIST_HEAD(&ret->ordered_list);
120 spin_lock_init(&ret->list_lock);
121 spin_lock_init(&ret->thres_lock);
122 trace_btrfs_workqueue_alloc(ret, name, flags & WQ_HIGHPRI);
123 return ret;
124}
125
126static inline void
127__btrfs_destroy_workqueue(struct __btrfs_workqueue *wq);
128
129struct btrfs_workqueue *btrfs_alloc_workqueue(struct btrfs_fs_info *fs_info,
130 const char *name,
131 unsigned int flags,
132 int limit_active,
133 int thresh)
134{
135 struct btrfs_workqueue *ret = kzalloc(sizeof(*ret), GFP_KERNEL);
136
137 if (!ret)
138 return NULL;
139
140 ret->normal = __btrfs_alloc_workqueue(fs_info, name,
141 flags & ~WQ_HIGHPRI,
142 limit_active, thresh);
143 if (!ret->normal) {
144 kfree(ret);
145 return NULL;
146 }
147
148 if (flags & WQ_HIGHPRI) {
149 ret->high = __btrfs_alloc_workqueue(fs_info, name, flags,
150 limit_active, thresh);
151 if (!ret->high) {
152 __btrfs_destroy_workqueue(ret->normal);
153 kfree(ret);
154 return NULL;
155 }
156 }
157 return ret;
158}
159
160
161
162
163
164
165static inline void thresh_queue_hook(struct __btrfs_workqueue *wq)
166{
167 if (wq->thresh == NO_THRESHOLD)
168 return;
169 atomic_inc(&wq->pending);
170}
171
172
173
174
175
176
177static inline void thresh_exec_hook(struct __btrfs_workqueue *wq)
178{
179 int new_current_active;
180 long pending;
181 int need_change = 0;
182
183 if (wq->thresh == NO_THRESHOLD)
184 return;
185
186 atomic_dec(&wq->pending);
187 spin_lock(&wq->thres_lock);
188
189
190
191
192 wq->count++;
193 wq->count %= (wq->thresh / 4);
194 if (!wq->count)
195 goto out;
196 new_current_active = wq->current_active;
197
198
199
200
201
202 pending = atomic_read(&wq->pending);
203 if (pending > wq->thresh)
204 new_current_active++;
205 if (pending < wq->thresh / 2)
206 new_current_active--;
207 new_current_active = clamp_val(new_current_active, 1, wq->limit_active);
208 if (new_current_active != wq->current_active) {
209 need_change = 1;
210 wq->current_active = new_current_active;
211 }
212out:
213 spin_unlock(&wq->thres_lock);
214
215 if (need_change) {
216 workqueue_set_max_active(wq->normal_wq, wq->current_active);
217 }
218}
219
220static void run_ordered_work(struct __btrfs_workqueue *wq,
221 struct btrfs_work *self)
222{
223 struct list_head *list = &wq->ordered_list;
224 struct btrfs_work *work;
225 spinlock_t *lock = &wq->list_lock;
226 unsigned long flags;
227 bool free_self = false;
228
229 while (1) {
230 spin_lock_irqsave(lock, flags);
231 if (list_empty(list))
232 break;
233 work = list_entry(list->next, struct btrfs_work,
234 ordered_list);
235 if (!test_bit(WORK_DONE_BIT, &work->flags))
236 break;
237
238
239
240
241
242
243
244 if (test_and_set_bit(WORK_ORDER_DONE_BIT, &work->flags))
245 break;
246 trace_btrfs_ordered_sched(work);
247 spin_unlock_irqrestore(lock, flags);
248 work->ordered_func(work);
249
250
251 spin_lock_irqsave(lock, flags);
252 list_del(&work->ordered_list);
253 spin_unlock_irqrestore(lock, flags);
254
255 if (work == self) {
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277 free_self = true;
278 } else {
279
280
281
282
283 work->ordered_free(work);
284
285 trace_btrfs_all_work_done(wq->fs_info, work);
286 }
287 }
288 spin_unlock_irqrestore(lock, flags);
289
290 if (free_self) {
291 self->ordered_free(self);
292
293 trace_btrfs_all_work_done(wq->fs_info, self);
294 }
295}
296
297static void btrfs_work_helper(struct work_struct *normal_work)
298{
299 struct btrfs_work *work = container_of(normal_work, struct btrfs_work,
300 normal_work);
301 struct __btrfs_workqueue *wq;
302 int need_order = 0;
303
304
305
306
307
308
309
310
311
312 if (work->ordered_func)
313 need_order = 1;
314 wq = work->wq;
315
316 trace_btrfs_work_sched(work);
317 thresh_exec_hook(wq);
318 work->func(work);
319 if (need_order) {
320 set_bit(WORK_DONE_BIT, &work->flags);
321 run_ordered_work(wq, work);
322 } else {
323
324 trace_btrfs_all_work_done(wq->fs_info, work);
325 }
326}
327
328void btrfs_init_work(struct btrfs_work *work, btrfs_func_t func,
329 btrfs_func_t ordered_func, btrfs_func_t ordered_free)
330{
331 work->func = func;
332 work->ordered_func = ordered_func;
333 work->ordered_free = ordered_free;
334 INIT_WORK(&work->normal_work, btrfs_work_helper);
335 INIT_LIST_HEAD(&work->ordered_list);
336 work->flags = 0;
337}
338
339static inline void __btrfs_queue_work(struct __btrfs_workqueue *wq,
340 struct btrfs_work *work)
341{
342 unsigned long flags;
343
344 work->wq = wq;
345 thresh_queue_hook(wq);
346 if (work->ordered_func) {
347 spin_lock_irqsave(&wq->list_lock, flags);
348 list_add_tail(&work->ordered_list, &wq->ordered_list);
349 spin_unlock_irqrestore(&wq->list_lock, flags);
350 }
351 trace_btrfs_work_queued(work);
352 queue_work(wq->normal_wq, &work->normal_work);
353}
354
355void btrfs_queue_work(struct btrfs_workqueue *wq,
356 struct btrfs_work *work)
357{
358 struct __btrfs_workqueue *dest_wq;
359
360 if (test_bit(WORK_HIGH_PRIO_BIT, &work->flags) && wq->high)
361 dest_wq = wq->high;
362 else
363 dest_wq = wq->normal;
364 __btrfs_queue_work(dest_wq, work);
365}
366
367static inline void
368__btrfs_destroy_workqueue(struct __btrfs_workqueue *wq)
369{
370 destroy_workqueue(wq->normal_wq);
371 trace_btrfs_workqueue_destroy(wq);
372 kfree(wq);
373}
374
375void btrfs_destroy_workqueue(struct btrfs_workqueue *wq)
376{
377 if (!wq)
378 return;
379 if (wq->high)
380 __btrfs_destroy_workqueue(wq->high);
381 __btrfs_destroy_workqueue(wq->normal);
382 kfree(wq);
383}
384
385void btrfs_workqueue_set_max(struct btrfs_workqueue *wq, int limit_active)
386{
387 if (!wq)
388 return;
389 wq->normal->limit_active = limit_active;
390 if (wq->high)
391 wq->high->limit_active = limit_active;
392}
393
394void btrfs_set_work_high_priority(struct btrfs_work *work)
395{
396 set_bit(WORK_HIGH_PRIO_BIT, &work->flags);
397}
398
399void btrfs_flush_workqueue(struct btrfs_workqueue *wq)
400{
401 if (wq->high)
402 flush_workqueue(wq->high->normal_wq);
403
404 flush_workqueue(wq->normal->normal_wq);
405}
406