1
2
3
4
5
6
7
8
9#include <linux/module.h>
10#include <linux/blkdev.h>
11#include <linux/elevator.h>
12#include <linux/rbtree.h>
13#include <linux/ioprio.h>
14#include <linux/blktrace_api.h>
15
16
17
18
19
20static const int cfq_quantum = 4;
21static const int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 };
22
23static const int cfq_back_max = 16 * 1024;
24
25static const int cfq_back_penalty = 2;
26static const int cfq_slice_sync = HZ / 10;
27static int cfq_slice_async = HZ / 25;
28static const int cfq_slice_async_rq = 2;
29static int cfq_slice_idle = HZ / 125;
30
31
32
33
34#define CFQ_IDLE_DELAY (HZ / 5)
35
36
37
38
39#define CFQ_MIN_TT (2)
40
41#define CFQ_SLICE_SCALE (5)
42#define CFQ_HW_QUEUE_MIN (5)
43
44#define RQ_CIC(rq) \
45 ((struct cfq_io_context *) (rq)->elevator_private)
46#define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elevator_private2)
47
48static struct kmem_cache *cfq_pool;
49static struct kmem_cache *cfq_ioc_pool;
50
51static DEFINE_PER_CPU(unsigned long, cfq_ioc_count);
52static struct completion *ioc_gone;
53static DEFINE_SPINLOCK(ioc_gone_lock);
54
55#define CFQ_PRIO_LISTS IOPRIO_BE_NR
56#define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE)
57#define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT)
58
59#define sample_valid(samples) ((samples) > 80)
60
61
62
63
64
65
66
67struct cfq_rb_root {
68 struct rb_root rb;
69 struct rb_node *left;
70};
71#define CFQ_RB_ROOT (struct cfq_rb_root) { RB_ROOT, NULL, }
72
73
74
75
76struct cfq_queue {
77
78 atomic_t ref;
79
80 unsigned int flags;
81
82 struct cfq_data *cfqd;
83
84 struct rb_node rb_node;
85
86 unsigned long rb_key;
87
88 struct rb_node p_node;
89
90 struct rb_root *p_root;
91
92 struct rb_root sort_list;
93
94 struct request *next_rq;
95
96 int queued[2];
97
98 int allocated[2];
99
100 struct list_head fifo;
101
102 unsigned long slice_end;
103 long slice_resid;
104 unsigned int slice_dispatch;
105
106
107 int meta_pending;
108
109 int dispatched;
110
111
112 unsigned short ioprio, org_ioprio;
113 unsigned short ioprio_class, org_ioprio_class;
114
115 pid_t pid;
116};
117
118
119
120
121struct cfq_data {
122 struct request_queue *queue;
123
124
125
126
127 struct cfq_rb_root service_tree;
128
129
130
131
132
133
134 struct rb_root prio_trees[CFQ_PRIO_LISTS];
135
136 unsigned int busy_queues;
137
138 int rq_in_driver[2];
139 int sync_flight;
140
141
142
143
144 int rq_queued;
145 int hw_tag;
146 int hw_tag_samples;
147 int rq_in_driver_peak;
148
149
150
151
152 struct timer_list idle_slice_timer;
153 struct work_struct unplug_work;
154
155 struct cfq_queue *active_queue;
156 struct cfq_io_context *active_cic;
157
158
159
160
161 struct cfq_queue *async_cfqq[2][IOPRIO_BE_NR];
162 struct cfq_queue *async_idle_cfqq;
163
164 sector_t last_position;
165
166
167
168
169 unsigned int cfq_quantum;
170 unsigned int cfq_fifo_expire[2];
171 unsigned int cfq_back_penalty;
172 unsigned int cfq_back_max;
173 unsigned int cfq_slice[2];
174 unsigned int cfq_slice_async_rq;
175 unsigned int cfq_slice_idle;
176 unsigned int cfq_latency;
177
178 struct list_head cic_list;
179
180
181
182
183 struct cfq_queue oom_cfqq;
184
185 unsigned long last_end_sync_rq;
186};
187
188enum cfqq_state_flags {
189 CFQ_CFQQ_FLAG_on_rr = 0,
190 CFQ_CFQQ_FLAG_wait_request,
191 CFQ_CFQQ_FLAG_must_dispatch,
192 CFQ_CFQQ_FLAG_must_alloc_slice,
193 CFQ_CFQQ_FLAG_fifo_expire,
194 CFQ_CFQQ_FLAG_idle_window,
195 CFQ_CFQQ_FLAG_prio_changed,
196 CFQ_CFQQ_FLAG_slice_new,
197 CFQ_CFQQ_FLAG_sync,
198 CFQ_CFQQ_FLAG_coop,
199 CFQ_CFQQ_FLAG_coop_preempt,
200};
201
202#define CFQ_CFQQ_FNS(name) \
203static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \
204{ \
205 (cfqq)->flags |= (1 << CFQ_CFQQ_FLAG_##name); \
206} \
207static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \
208{ \
209 (cfqq)->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \
210} \
211static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \
212{ \
213 return ((cfqq)->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \
214}
215
216CFQ_CFQQ_FNS(on_rr);
217CFQ_CFQQ_FNS(wait_request);
218CFQ_CFQQ_FNS(must_dispatch);
219CFQ_CFQQ_FNS(must_alloc_slice);
220CFQ_CFQQ_FNS(fifo_expire);
221CFQ_CFQQ_FNS(idle_window);
222CFQ_CFQQ_FNS(prio_changed);
223CFQ_CFQQ_FNS(slice_new);
224CFQ_CFQQ_FNS(sync);
225CFQ_CFQQ_FNS(coop);
226CFQ_CFQQ_FNS(coop_preempt);
227#undef CFQ_CFQQ_FNS
228
229#define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \
230 blk_add_trace_msg((cfqd)->queue, "cfq%d " fmt, (cfqq)->pid, ##args)
231#define cfq_log(cfqd, fmt, args...) \
232 blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args)
233
234static void cfq_dispatch_insert(struct request_queue *, struct request *);
235static struct cfq_queue *cfq_get_queue(struct cfq_data *, bool,
236 struct io_context *, gfp_t);
237static struct cfq_io_context *cfq_cic_lookup(struct cfq_data *,
238 struct io_context *);
239
240static inline int rq_in_driver(struct cfq_data *cfqd)
241{
242 return cfqd->rq_in_driver[0] + cfqd->rq_in_driver[1];
243}
244
245static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_context *cic,
246 bool is_sync)
247{
248 return cic->cfqq[is_sync];
249}
250
251static inline void cic_set_cfqq(struct cfq_io_context *cic,
252 struct cfq_queue *cfqq, bool is_sync)
253{
254 cic->cfqq[is_sync] = cfqq;
255}
256
257
258
259
260
261static inline bool cfq_bio_sync(struct bio *bio)
262{
263 return bio_data_dir(bio) == READ || bio_rw_flagged(bio, BIO_RW_SYNCIO);
264}
265
266
267
268
269
270static inline void cfq_schedule_dispatch(struct cfq_data *cfqd)
271{
272 if (cfqd->busy_queues) {
273 cfq_log(cfqd, "schedule dispatch");
274 kblockd_schedule_work(cfqd->queue, &cfqd->unplug_work);
275 }
276}
277
278static int cfq_queue_empty(struct request_queue *q)
279{
280 struct cfq_data *cfqd = q->elevator->elevator_data;
281
282 return !cfqd->busy_queues;
283}
284
285
286
287
288
289
290static inline int cfq_prio_slice(struct cfq_data *cfqd, bool sync,
291 unsigned short prio)
292{
293 const int base_slice = cfqd->cfq_slice[sync];
294
295 WARN_ON(prio >= IOPRIO_BE_NR);
296
297 return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - prio));
298}
299
300static inline int
301cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
302{
303 return cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio);
304}
305
306static inline void
307cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
308{
309 cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies;
310 cfq_log_cfqq(cfqd, cfqq, "set_slice=%lu", cfqq->slice_end - jiffies);
311}
312
313
314
315
316
317
318static inline bool cfq_slice_used(struct cfq_queue *cfqq)
319{
320 if (cfq_cfqq_slice_new(cfqq))
321 return 0;
322 if (time_before(jiffies, cfqq->slice_end))
323 return 0;
324
325 return 1;
326}
327
328
329
330
331
332
333static struct request *
334cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2)
335{
336 sector_t last, s1, s2, d1 = 0, d2 = 0;
337 unsigned long back_max;
338#define CFQ_RQ1_WRAP 0x01
339#define CFQ_RQ2_WRAP 0x02
340 unsigned wrap = 0;
341
342 if (rq1 == NULL || rq1 == rq2)
343 return rq2;
344 if (rq2 == NULL)
345 return rq1;
346
347 if (rq_is_sync(rq1) && !rq_is_sync(rq2))
348 return rq1;
349 else if (rq_is_sync(rq2) && !rq_is_sync(rq1))
350 return rq2;
351 if (rq_is_meta(rq1) && !rq_is_meta(rq2))
352 return rq1;
353 else if (rq_is_meta(rq2) && !rq_is_meta(rq1))
354 return rq2;
355
356 s1 = blk_rq_pos(rq1);
357 s2 = blk_rq_pos(rq2);
358
359 last = cfqd->last_position;
360
361
362
363
364 back_max = cfqd->cfq_back_max * 2;
365
366
367
368
369
370
371 if (s1 >= last)
372 d1 = s1 - last;
373 else if (s1 + back_max >= last)
374 d1 = (last - s1) * cfqd->cfq_back_penalty;
375 else
376 wrap |= CFQ_RQ1_WRAP;
377
378 if (s2 >= last)
379 d2 = s2 - last;
380 else if (s2 + back_max >= last)
381 d2 = (last - s2) * cfqd->cfq_back_penalty;
382 else
383 wrap |= CFQ_RQ2_WRAP;
384
385
386
387
388
389
390
391 switch (wrap) {
392 case 0:
393 if (d1 < d2)
394 return rq1;
395 else if (d2 < d1)
396 return rq2;
397 else {
398 if (s1 >= s2)
399 return rq1;
400 else
401 return rq2;
402 }
403
404 case CFQ_RQ2_WRAP:
405 return rq1;
406 case CFQ_RQ1_WRAP:
407 return rq2;
408 case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP):
409 default:
410
411
412
413
414
415
416 if (s1 <= s2)
417 return rq1;
418 else
419 return rq2;
420 }
421}
422
423
424
425
426static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root)
427{
428 if (!root->left)
429 root->left = rb_first(&root->rb);
430
431 if (root->left)
432 return rb_entry(root->left, struct cfq_queue, rb_node);
433
434 return NULL;
435}
436
437static void rb_erase_init(struct rb_node *n, struct rb_root *root)
438{
439 rb_erase(n, root);
440 RB_CLEAR_NODE(n);
441}
442
443static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root)
444{
445 if (root->left == n)
446 root->left = NULL;
447 rb_erase_init(n, &root->rb);
448}
449
450
451
452
453static struct request *
454cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
455 struct request *last)
456{
457 struct rb_node *rbnext = rb_next(&last->rb_node);
458 struct rb_node *rbprev = rb_prev(&last->rb_node);
459 struct request *next = NULL, *prev = NULL;
460
461 BUG_ON(RB_EMPTY_NODE(&last->rb_node));
462
463 if (rbprev)
464 prev = rb_entry_rq(rbprev);
465
466 if (rbnext)
467 next = rb_entry_rq(rbnext);
468 else {
469 rbnext = rb_first(&cfqq->sort_list);
470 if (rbnext && rbnext != &last->rb_node)
471 next = rb_entry_rq(rbnext);
472 }
473
474 return cfq_choose_req(cfqd, next, prev);
475}
476
477static unsigned long cfq_slice_offset(struct cfq_data *cfqd,
478 struct cfq_queue *cfqq)
479{
480
481
482
483 return (cfqd->busy_queues - 1) * (cfq_prio_slice(cfqd, 1, 0) -
484 cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio));
485}
486
487
488
489
490
491
492static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
493 bool add_front)
494{
495 struct rb_node **p, *parent;
496 struct cfq_queue *__cfqq;
497 unsigned long rb_key;
498 int left;
499
500 if (cfq_class_idle(cfqq)) {
501 rb_key = CFQ_IDLE_DELAY;
502 parent = rb_last(&cfqd->service_tree.rb);
503 if (parent && parent != &cfqq->rb_node) {
504 __cfqq = rb_entry(parent, struct cfq_queue, rb_node);
505 rb_key += __cfqq->rb_key;
506 } else
507 rb_key += jiffies;
508 } else if (!add_front) {
509
510
511
512
513
514
515 rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies;
516 rb_key -= cfqq->slice_resid;
517 cfqq->slice_resid = 0;
518 } else {
519 rb_key = -HZ;
520 __cfqq = cfq_rb_first(&cfqd->service_tree);
521 rb_key += __cfqq ? __cfqq->rb_key : jiffies;
522 }
523
524 if (!RB_EMPTY_NODE(&cfqq->rb_node)) {
525
526
527
528 if (rb_key == cfqq->rb_key)
529 return;
530
531 cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree);
532 }
533
534 left = 1;
535 parent = NULL;
536 p = &cfqd->service_tree.rb.rb_node;
537 while (*p) {
538 struct rb_node **n;
539
540 parent = *p;
541 __cfqq = rb_entry(parent, struct cfq_queue, rb_node);
542
543
544
545
546
547
548 if (cfq_class_rt(cfqq) > cfq_class_rt(__cfqq))
549 n = &(*p)->rb_left;
550 else if (cfq_class_rt(cfqq) < cfq_class_rt(__cfqq))
551 n = &(*p)->rb_right;
552 else if (cfq_class_idle(cfqq) < cfq_class_idle(__cfqq))
553 n = &(*p)->rb_left;
554 else if (cfq_class_idle(cfqq) > cfq_class_idle(__cfqq))
555 n = &(*p)->rb_right;
556 else if (time_before(rb_key, __cfqq->rb_key))
557 n = &(*p)->rb_left;
558 else
559 n = &(*p)->rb_right;
560
561 if (n == &(*p)->rb_right)
562 left = 0;
563
564 p = n;
565 }
566
567 if (left)
568 cfqd->service_tree.left = &cfqq->rb_node;
569
570 cfqq->rb_key = rb_key;
571 rb_link_node(&cfqq->rb_node, parent, p);
572 rb_insert_color(&cfqq->rb_node, &cfqd->service_tree.rb);
573}
574
575static struct cfq_queue *
576cfq_prio_tree_lookup(struct cfq_data *cfqd, struct rb_root *root,
577 sector_t sector, struct rb_node **ret_parent,
578 struct rb_node ***rb_link)
579{
580 struct rb_node **p, *parent;
581 struct cfq_queue *cfqq = NULL;
582
583 parent = NULL;
584 p = &root->rb_node;
585 while (*p) {
586 struct rb_node **n;
587
588 parent = *p;
589 cfqq = rb_entry(parent, struct cfq_queue, p_node);
590
591
592
593
594
595 if (sector > blk_rq_pos(cfqq->next_rq))
596 n = &(*p)->rb_right;
597 else if (sector < blk_rq_pos(cfqq->next_rq))
598 n = &(*p)->rb_left;
599 else
600 break;
601 p = n;
602 cfqq = NULL;
603 }
604
605 *ret_parent = parent;
606 if (rb_link)
607 *rb_link = p;
608 return cfqq;
609}
610
611static void cfq_prio_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq)
612{
613 struct rb_node **p, *parent;
614 struct cfq_queue *__cfqq;
615
616 if (cfqq->p_root) {
617 rb_erase(&cfqq->p_node, cfqq->p_root);
618 cfqq->p_root = NULL;
619 }
620
621 if (cfq_class_idle(cfqq))
622 return;
623 if (!cfqq->next_rq)
624 return;
625
626 cfqq->p_root = &cfqd->prio_trees[cfqq->org_ioprio];
627 __cfqq = cfq_prio_tree_lookup(cfqd, cfqq->p_root,
628 blk_rq_pos(cfqq->next_rq), &parent, &p);
629 if (!__cfqq) {
630 rb_link_node(&cfqq->p_node, parent, p);
631 rb_insert_color(&cfqq->p_node, cfqq->p_root);
632 } else
633 cfqq->p_root = NULL;
634}
635
636
637
638
639static void cfq_resort_rr_list(struct cfq_data *cfqd, struct cfq_queue *cfqq)
640{
641
642
643
644 if (cfq_cfqq_on_rr(cfqq)) {
645 cfq_service_tree_add(cfqd, cfqq, 0);
646 cfq_prio_tree_add(cfqd, cfqq);
647 }
648}
649
650
651
652
653
654static void cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
655{
656 cfq_log_cfqq(cfqd, cfqq, "add_to_rr");
657 BUG_ON(cfq_cfqq_on_rr(cfqq));
658 cfq_mark_cfqq_on_rr(cfqq);
659 cfqd->busy_queues++;
660
661 cfq_resort_rr_list(cfqd, cfqq);
662}
663
664
665
666
667
668static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
669{
670 cfq_log_cfqq(cfqd, cfqq, "del_from_rr");
671 BUG_ON(!cfq_cfqq_on_rr(cfqq));
672 cfq_clear_cfqq_on_rr(cfqq);
673
674 if (!RB_EMPTY_NODE(&cfqq->rb_node))
675 cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree);
676 if (cfqq->p_root) {
677 rb_erase(&cfqq->p_node, cfqq->p_root);
678 cfqq->p_root = NULL;
679 }
680
681 BUG_ON(!cfqd->busy_queues);
682 cfqd->busy_queues--;
683}
684
685
686
687
688static void cfq_del_rq_rb(struct request *rq)
689{
690 struct cfq_queue *cfqq = RQ_CFQQ(rq);
691 struct cfq_data *cfqd = cfqq->cfqd;
692 const int sync = rq_is_sync(rq);
693
694 BUG_ON(!cfqq->queued[sync]);
695 cfqq->queued[sync]--;
696
697 elv_rb_del(&cfqq->sort_list, rq);
698
699 if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list))
700 cfq_del_cfqq_rr(cfqd, cfqq);
701}
702
703static void cfq_add_rq_rb(struct request *rq)
704{
705 struct cfq_queue *cfqq = RQ_CFQQ(rq);
706 struct cfq_data *cfqd = cfqq->cfqd;
707 struct request *__alias, *prev;
708
709 cfqq->queued[rq_is_sync(rq)]++;
710
711
712
713
714
715 while ((__alias = elv_rb_add(&cfqq->sort_list, rq)) != NULL)
716 cfq_dispatch_insert(cfqd->queue, __alias);
717
718 if (!cfq_cfqq_on_rr(cfqq))
719 cfq_add_cfqq_rr(cfqd, cfqq);
720
721
722
723
724 prev = cfqq->next_rq;
725 cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq);
726
727
728
729
730 if (prev != cfqq->next_rq)
731 cfq_prio_tree_add(cfqd, cfqq);
732
733 BUG_ON(!cfqq->next_rq);
734}
735
736static void cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq)
737{
738 elv_rb_del(&cfqq->sort_list, rq);
739 cfqq->queued[rq_is_sync(rq)]--;
740 cfq_add_rq_rb(rq);
741}
742
743static struct request *
744cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio)
745{
746 struct task_struct *tsk = current;
747 struct cfq_io_context *cic;
748 struct cfq_queue *cfqq;
749
750 cic = cfq_cic_lookup(cfqd, tsk->io_context);
751 if (!cic)
752 return NULL;
753
754 cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio));
755 if (cfqq) {
756 sector_t sector = bio->bi_sector + bio_sectors(bio);
757
758 return elv_rb_find(&cfqq->sort_list, sector);
759 }
760
761 return NULL;
762}
763
764static void cfq_activate_request(struct request_queue *q, struct request *rq)
765{
766 struct cfq_data *cfqd = q->elevator->elevator_data;
767
768 cfqd->rq_in_driver[rq_is_sync(rq)]++;
769 cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "activate rq, drv=%d",
770 rq_in_driver(cfqd));
771
772 cfqd->last_position = blk_rq_pos(rq) + blk_rq_sectors(rq);
773}
774
775static void cfq_deactivate_request(struct request_queue *q, struct request *rq)
776{
777 struct cfq_data *cfqd = q->elevator->elevator_data;
778 const int sync = rq_is_sync(rq);
779
780 WARN_ON(!cfqd->rq_in_driver[sync]);
781 cfqd->rq_in_driver[sync]--;
782 cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "deactivate rq, drv=%d",
783 rq_in_driver(cfqd));
784}
785
786static void cfq_remove_request(struct request *rq)
787{
788 struct cfq_queue *cfqq = RQ_CFQQ(rq);
789
790 if (cfqq->next_rq == rq)
791 cfqq->next_rq = cfq_find_next_rq(cfqq->cfqd, cfqq, rq);
792
793 list_del_init(&rq->queuelist);
794 cfq_del_rq_rb(rq);
795
796 cfqq->cfqd->rq_queued--;
797 if (rq_is_meta(rq)) {
798 WARN_ON(!cfqq->meta_pending);
799 cfqq->meta_pending--;
800 }
801}
802
803static int cfq_merge(struct request_queue *q, struct request **req,
804 struct bio *bio)
805{
806 struct cfq_data *cfqd = q->elevator->elevator_data;
807 struct request *__rq;
808
809 __rq = cfq_find_rq_fmerge(cfqd, bio);
810 if (__rq && elv_rq_merge_ok(__rq, bio)) {
811 *req = __rq;
812 return ELEVATOR_FRONT_MERGE;
813 }
814
815 return ELEVATOR_NO_MERGE;
816}
817
818static void cfq_merged_request(struct request_queue *q, struct request *req,
819 int type)
820{
821 if (type == ELEVATOR_FRONT_MERGE) {
822 struct cfq_queue *cfqq = RQ_CFQQ(req);
823
824 cfq_reposition_rq_rb(cfqq, req);
825 }
826}
827
828static void
829cfq_merged_requests(struct request_queue *q, struct request *rq,
830 struct request *next)
831{
832
833
834
835 if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) &&
836 time_before(rq_fifo_time(next), rq_fifo_time(rq))) {
837 list_move(&rq->queuelist, &next->queuelist);
838 rq_set_fifo_time(rq, rq_fifo_time(next));
839 }
840
841 cfq_remove_request(next);
842}
843
844static int cfq_allow_merge(struct request_queue *q, struct request *rq,
845 struct bio *bio)
846{
847 struct cfq_data *cfqd = q->elevator->elevator_data;
848 struct cfq_io_context *cic;
849 struct cfq_queue *cfqq;
850
851
852
853
854 if (cfq_bio_sync(bio) && !rq_is_sync(rq))
855 return false;
856
857
858
859
860
861 cic = cfq_cic_lookup(cfqd, current->io_context);
862 if (!cic)
863 return false;
864
865 cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio));
866 return cfqq == RQ_CFQQ(rq);
867}
868
869static void __cfq_set_active_queue(struct cfq_data *cfqd,
870 struct cfq_queue *cfqq)
871{
872 if (cfqq) {
873 cfq_log_cfqq(cfqd, cfqq, "set_active");
874 cfqq->slice_end = 0;
875 cfqq->slice_dispatch = 0;
876
877 cfq_clear_cfqq_wait_request(cfqq);
878 cfq_clear_cfqq_must_dispatch(cfqq);
879 cfq_clear_cfqq_must_alloc_slice(cfqq);
880 cfq_clear_cfqq_fifo_expire(cfqq);
881 cfq_mark_cfqq_slice_new(cfqq);
882
883 del_timer(&cfqd->idle_slice_timer);
884 }
885
886 cfqd->active_queue = cfqq;
887}
888
889
890
891
892static void
893__cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
894 bool timed_out)
895{
896 cfq_log_cfqq(cfqd, cfqq, "slice expired t=%d", timed_out);
897
898 if (cfq_cfqq_wait_request(cfqq))
899 del_timer(&cfqd->idle_slice_timer);
900
901 cfq_clear_cfqq_wait_request(cfqq);
902
903
904
905
906 if (timed_out && !cfq_cfqq_slice_new(cfqq)) {
907 cfqq->slice_resid = cfqq->slice_end - jiffies;
908 cfq_log_cfqq(cfqd, cfqq, "resid=%ld", cfqq->slice_resid);
909 }
910
911 cfq_resort_rr_list(cfqd, cfqq);
912
913 if (cfqq == cfqd->active_queue)
914 cfqd->active_queue = NULL;
915
916 if (cfqd->active_cic) {
917 put_io_context(cfqd->active_cic->ioc);
918 cfqd->active_cic = NULL;
919 }
920}
921
922static inline void cfq_slice_expired(struct cfq_data *cfqd, bool timed_out)
923{
924 struct cfq_queue *cfqq = cfqd->active_queue;
925
926 if (cfqq)
927 __cfq_slice_expired(cfqd, cfqq, timed_out);
928}
929
930
931
932
933
934static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd)
935{
936 if (RB_EMPTY_ROOT(&cfqd->service_tree.rb))
937 return NULL;
938
939 return cfq_rb_first(&cfqd->service_tree);
940}
941
942
943
944
945static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd,
946 struct cfq_queue *cfqq)
947{
948 if (!cfqq) {
949 cfqq = cfq_get_next_queue(cfqd);
950 if (cfqq && !cfq_cfqq_coop_preempt(cfqq))
951 cfq_clear_cfqq_coop(cfqq);
952 }
953
954 if (cfqq)
955 cfq_clear_cfqq_coop_preempt(cfqq);
956
957 __cfq_set_active_queue(cfqd, cfqq);
958 return cfqq;
959}
960
961static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd,
962 struct request *rq)
963{
964 if (blk_rq_pos(rq) >= cfqd->last_position)
965 return blk_rq_pos(rq) - cfqd->last_position;
966 else
967 return cfqd->last_position - blk_rq_pos(rq);
968}
969
970#define CIC_SEEK_THR 8 * 1024
971#define CIC_SEEKY(cic) ((cic)->seek_mean > CIC_SEEK_THR)
972
973static inline int cfq_rq_close(struct cfq_data *cfqd, struct request *rq)
974{
975 struct cfq_io_context *cic = cfqd->active_cic;
976 sector_t sdist = cic->seek_mean;
977
978 if (!sample_valid(cic->seek_samples))
979 sdist = CIC_SEEK_THR;
980
981 return cfq_dist_from_last(cfqd, rq) <= sdist;
982}
983
984static struct cfq_queue *cfqq_close(struct cfq_data *cfqd,
985 struct cfq_queue *cur_cfqq)
986{
987 struct rb_root *root = &cfqd->prio_trees[cur_cfqq->org_ioprio];
988 struct rb_node *parent, *node;
989 struct cfq_queue *__cfqq;
990 sector_t sector = cfqd->last_position;
991
992 if (RB_EMPTY_ROOT(root))
993 return NULL;
994
995
996
997
998
999 __cfqq = cfq_prio_tree_lookup(cfqd, root, sector, &parent, NULL);
1000 if (__cfqq)
1001 return __cfqq;
1002
1003
1004
1005
1006
1007 __cfqq = rb_entry(parent, struct cfq_queue, p_node);
1008 if (cfq_rq_close(cfqd, __cfqq->next_rq))
1009 return __cfqq;
1010
1011 if (blk_rq_pos(__cfqq->next_rq) < sector)
1012 node = rb_next(&__cfqq->p_node);
1013 else
1014 node = rb_prev(&__cfqq->p_node);
1015 if (!node)
1016 return NULL;
1017
1018 __cfqq = rb_entry(node, struct cfq_queue, p_node);
1019 if (cfq_rq_close(cfqd, __cfqq->next_rq))
1020 return __cfqq;
1021
1022 return NULL;
1023}
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd,
1036 struct cfq_queue *cur_cfqq,
1037 bool probe)
1038{
1039 struct cfq_queue *cfqq;
1040
1041
1042
1043
1044
1045 if (!cfqd->active_cic)
1046 return NULL;
1047
1048
1049
1050
1051
1052
1053 cfqq = cfqq_close(cfqd, cur_cfqq);
1054 if (!cfqq)
1055 return NULL;
1056
1057 if (cfq_cfqq_coop(cfqq))
1058 return NULL;
1059
1060 if (!probe)
1061 cfq_mark_cfqq_coop(cfqq);
1062 return cfqq;
1063}
1064
1065static void cfq_arm_slice_timer(struct cfq_data *cfqd)
1066{
1067 struct cfq_queue *cfqq = cfqd->active_queue;
1068 struct cfq_io_context *cic;
1069 unsigned long sl;
1070
1071
1072
1073
1074
1075
1076 if (blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag)
1077 return;
1078
1079 WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list));
1080 WARN_ON(cfq_cfqq_slice_new(cfqq));
1081
1082
1083
1084
1085 if (!cfqd->cfq_slice_idle || !cfq_cfqq_idle_window(cfqq))
1086 return;
1087
1088
1089
1090
1091 if (rq_in_driver(cfqd))
1092 return;
1093
1094
1095
1096
1097 cic = cfqd->active_cic;
1098 if (!cic || !atomic_read(&cic->ioc->nr_tasks))
1099 return;
1100
1101
1102
1103
1104
1105
1106 if (sample_valid(cic->ttime_samples) &&
1107 (cfqq->slice_end - jiffies < cic->ttime_mean))
1108 return;
1109
1110 cfq_mark_cfqq_wait_request(cfqq);
1111
1112
1113
1114
1115
1116
1117 sl = cfqd->cfq_slice_idle;
1118 if (sample_valid(cic->seek_samples) && CIC_SEEKY(cic))
1119 sl = min(sl, msecs_to_jiffies(CFQ_MIN_TT));
1120
1121 mod_timer(&cfqd->idle_slice_timer, jiffies + sl);
1122 cfq_log_cfqq(cfqd, cfqq, "arm_idle: %lu", sl);
1123}
1124
1125
1126
1127
1128static void cfq_dispatch_insert(struct request_queue *q, struct request *rq)
1129{
1130 struct cfq_data *cfqd = q->elevator->elevator_data;
1131 struct cfq_queue *cfqq = RQ_CFQQ(rq);
1132
1133 cfq_log_cfqq(cfqd, cfqq, "dispatch_insert");
1134
1135 cfqq->next_rq = cfq_find_next_rq(cfqd, cfqq, rq);
1136 cfq_remove_request(rq);
1137 cfqq->dispatched++;
1138 elv_dispatch_sort(q, rq);
1139
1140 if (cfq_cfqq_sync(cfqq))
1141 cfqd->sync_flight++;
1142}
1143
1144
1145
1146
1147static struct request *cfq_check_fifo(struct cfq_queue *cfqq)
1148{
1149 struct request *rq = NULL;
1150
1151 if (cfq_cfqq_fifo_expire(cfqq))
1152 return NULL;
1153
1154 cfq_mark_cfqq_fifo_expire(cfqq);
1155
1156 if (list_empty(&cfqq->fifo))
1157 return NULL;
1158
1159 rq = rq_entry_fifo(cfqq->fifo.next);
1160 if (time_before(jiffies, rq_fifo_time(rq)))
1161 rq = NULL;
1162
1163 cfq_log_cfqq(cfqq->cfqd, cfqq, "fifo=%p", rq);
1164 return rq;
1165}
1166
1167static inline int
1168cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
1169{
1170 const int base_rq = cfqd->cfq_slice_async_rq;
1171
1172 WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR);
1173
1174 return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio));
1175}
1176
1177
1178
1179
1180
1181static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
1182{
1183 struct cfq_queue *cfqq, *new_cfqq = NULL;
1184
1185 cfqq = cfqd->active_queue;
1186 if (!cfqq)
1187 goto new_queue;
1188
1189
1190
1191
1192 if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq))
1193 goto expire;
1194
1195
1196
1197
1198
1199 if (!RB_EMPTY_ROOT(&cfqq->sort_list))
1200 goto keep_queue;
1201
1202
1203
1204
1205
1206
1207
1208 new_cfqq = cfq_close_cooperator(cfqd, cfqq, 0);
1209 if (new_cfqq)
1210 goto expire;
1211
1212
1213
1214
1215
1216
1217 if (timer_pending(&cfqd->idle_slice_timer) ||
1218 (cfqq->dispatched && cfq_cfqq_idle_window(cfqq))) {
1219 cfqq = NULL;
1220 goto keep_queue;
1221 }
1222
1223expire:
1224 cfq_slice_expired(cfqd, 0);
1225new_queue:
1226 cfqq = cfq_set_active_queue(cfqd, new_cfqq);
1227keep_queue:
1228 return cfqq;
1229}
1230
1231static int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq)
1232{
1233 int dispatched = 0;
1234
1235 while (cfqq->next_rq) {
1236 cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq);
1237 dispatched++;
1238 }
1239
1240 BUG_ON(!list_empty(&cfqq->fifo));
1241 return dispatched;
1242}
1243
1244
1245
1246
1247
1248static int cfq_forced_dispatch(struct cfq_data *cfqd)
1249{
1250 struct cfq_queue *cfqq;
1251 int dispatched = 0;
1252
1253 while ((cfqq = cfq_rb_first(&cfqd->service_tree)) != NULL)
1254 dispatched += __cfq_forced_dispatch_cfqq(cfqq);
1255
1256 cfq_slice_expired(cfqd, 0);
1257
1258 BUG_ON(cfqd->busy_queues);
1259
1260 cfq_log(cfqd, "forced_dispatch=%d", dispatched);
1261 return dispatched;
1262}
1263
1264static bool cfq_may_dispatch(struct cfq_data *cfqd, struct cfq_queue *cfqq)
1265{
1266 unsigned int max_dispatch;
1267
1268
1269
1270
1271 if (cfq_cfqq_idle_window(cfqq) && cfqd->rq_in_driver[BLK_RW_ASYNC])
1272 return false;
1273
1274
1275
1276
1277 if (cfqd->sync_flight && !cfq_cfqq_sync(cfqq))
1278 return false;
1279
1280 max_dispatch = cfqd->cfq_quantum;
1281 if (cfq_class_idle(cfqq))
1282 max_dispatch = 1;
1283
1284
1285
1286
1287 if (cfqq->dispatched >= max_dispatch) {
1288
1289
1290
1291 if (cfq_class_idle(cfqq))
1292 return false;
1293
1294
1295
1296
1297 if (cfqd->busy_queues > 1)
1298 return false;
1299
1300
1301
1302
1303 max_dispatch *= 4;
1304 }
1305
1306
1307
1308
1309
1310
1311 if (!cfq_cfqq_sync(cfqq) && cfqd->cfq_latency) {
1312 unsigned long last_sync = jiffies - cfqd->last_end_sync_rq;
1313 unsigned int depth;
1314
1315 depth = last_sync / cfqd->cfq_slice[1];
1316 if (!depth && !cfqq->dispatched)
1317 depth = 1;
1318 if (depth < max_dispatch)
1319 max_dispatch = depth;
1320 }
1321
1322
1323
1324
1325 return cfqq->dispatched < max_dispatch;
1326}
1327
1328
1329
1330
1331
1332static bool cfq_dispatch_request(struct cfq_data *cfqd, struct cfq_queue *cfqq)
1333{
1334 struct request *rq;
1335
1336 BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list));
1337
1338 if (!cfq_may_dispatch(cfqd, cfqq))
1339 return false;
1340
1341
1342
1343
1344 rq = cfq_check_fifo(cfqq);
1345 if (!rq)
1346 rq = cfqq->next_rq;
1347
1348
1349
1350
1351 cfq_dispatch_insert(cfqd->queue, rq);
1352
1353 if (!cfqd->active_cic) {
1354 struct cfq_io_context *cic = RQ_CIC(rq);
1355
1356 atomic_long_inc(&cic->ioc->refcount);
1357 cfqd->active_cic = cic;
1358 }
1359
1360 return true;
1361}
1362
1363
1364
1365
1366
1367static int cfq_dispatch_requests(struct request_queue *q, int force)
1368{
1369 struct cfq_data *cfqd = q->elevator->elevator_data;
1370 struct cfq_queue *cfqq;
1371
1372 if (!cfqd->busy_queues)
1373 return 0;
1374
1375 if (unlikely(force))
1376 return cfq_forced_dispatch(cfqd);
1377
1378 cfqq = cfq_select_queue(cfqd);
1379 if (!cfqq)
1380 return 0;
1381
1382
1383
1384
1385 if (!cfq_dispatch_request(cfqd, cfqq))
1386 return 0;
1387
1388 cfqq->slice_dispatch++;
1389 cfq_clear_cfqq_must_dispatch(cfqq);
1390
1391
1392
1393
1394
1395 if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) &&
1396 cfqq->slice_dispatch >= cfq_prio_to_maxrq(cfqd, cfqq)) ||
1397 cfq_class_idle(cfqq))) {
1398 cfqq->slice_end = jiffies + 1;
1399 cfq_slice_expired(cfqd, 0);
1400 }
1401
1402 cfq_log_cfqq(cfqd, cfqq, "dispatched a request");
1403 return 1;
1404}
1405
1406
1407
1408
1409
1410
1411
1412static void cfq_put_queue(struct cfq_queue *cfqq)
1413{
1414 struct cfq_data *cfqd = cfqq->cfqd;
1415
1416 BUG_ON(atomic_read(&cfqq->ref) <= 0);
1417
1418 if (!atomic_dec_and_test(&cfqq->ref))
1419 return;
1420
1421 cfq_log_cfqq(cfqd, cfqq, "put_queue");
1422 BUG_ON(rb_first(&cfqq->sort_list));
1423 BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]);
1424 BUG_ON(cfq_cfqq_on_rr(cfqq));
1425
1426 if (unlikely(cfqd->active_queue == cfqq)) {
1427 __cfq_slice_expired(cfqd, cfqq, 0);
1428 cfq_schedule_dispatch(cfqd);
1429 }
1430
1431 kmem_cache_free(cfq_pool, cfqq);
1432}
1433
1434
1435
1436
1437static void
1438__call_for_each_cic(struct io_context *ioc,
1439 void (*func)(struct io_context *, struct cfq_io_context *))
1440{
1441 struct cfq_io_context *cic;
1442 struct hlist_node *n;
1443
1444 hlist_for_each_entry_rcu(cic, n, &ioc->cic_list, cic_list)
1445 func(ioc, cic);
1446}
1447
1448
1449
1450
1451static void
1452call_for_each_cic(struct io_context *ioc,
1453 void (*func)(struct io_context *, struct cfq_io_context *))
1454{
1455 rcu_read_lock();
1456 __call_for_each_cic(ioc, func);
1457 rcu_read_unlock();
1458}
1459
1460static void cfq_cic_free_rcu(struct rcu_head *head)
1461{
1462 struct cfq_io_context *cic;
1463
1464 cic = container_of(head, struct cfq_io_context, rcu_head);
1465
1466 kmem_cache_free(cfq_ioc_pool, cic);
1467 elv_ioc_count_dec(cfq_ioc_count);
1468
1469 if (ioc_gone) {
1470
1471
1472
1473
1474
1475 spin_lock(&ioc_gone_lock);
1476 if (ioc_gone && !elv_ioc_count_read(cfq_ioc_count)) {
1477 complete(ioc_gone);
1478 ioc_gone = NULL;
1479 }
1480 spin_unlock(&ioc_gone_lock);
1481 }
1482}
1483
1484static void cfq_cic_free(struct cfq_io_context *cic)
1485{
1486 call_rcu(&cic->rcu_head, cfq_cic_free_rcu);
1487}
1488
1489static void cic_free_func(struct io_context *ioc, struct cfq_io_context *cic)
1490{
1491 unsigned long flags;
1492
1493 BUG_ON(!cic->dead_key);
1494
1495 spin_lock_irqsave(&ioc->lock, flags);
1496 radix_tree_delete(&ioc->radix_root, cic->dead_key);
1497 hlist_del_rcu(&cic->cic_list);
1498 spin_unlock_irqrestore(&ioc->lock, flags);
1499
1500 cfq_cic_free(cic);
1501}
1502
1503
1504
1505
1506
1507
1508static void cfq_free_io_context(struct io_context *ioc)
1509{
1510
1511
1512
1513
1514
1515
1516 __call_for_each_cic(ioc, cic_free_func);
1517}
1518
1519static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
1520{
1521 if (unlikely(cfqq == cfqd->active_queue)) {
1522 __cfq_slice_expired(cfqd, cfqq, 0);
1523 cfq_schedule_dispatch(cfqd);
1524 }
1525
1526 cfq_put_queue(cfqq);
1527}
1528
1529static void __cfq_exit_single_io_context(struct cfq_data *cfqd,
1530 struct cfq_io_context *cic)
1531{
1532 struct io_context *ioc = cic->ioc;
1533
1534 list_del_init(&cic->queue_list);
1535
1536
1537
1538
1539 smp_wmb();
1540 cic->dead_key = (unsigned long) cic->key;
1541 cic->key = NULL;
1542
1543 if (ioc->ioc_data == cic)
1544 rcu_assign_pointer(ioc->ioc_data, NULL);
1545
1546 if (cic->cfqq[BLK_RW_ASYNC]) {
1547 cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_ASYNC]);
1548 cic->cfqq[BLK_RW_ASYNC] = NULL;
1549 }
1550
1551 if (cic->cfqq[BLK_RW_SYNC]) {
1552 cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_SYNC]);
1553 cic->cfqq[BLK_RW_SYNC] = NULL;
1554 }
1555}
1556
1557static void cfq_exit_single_io_context(struct io_context *ioc,
1558 struct cfq_io_context *cic)
1559{
1560 struct cfq_data *cfqd = cic->key;
1561
1562 if (cfqd) {
1563 struct request_queue *q = cfqd->queue;
1564 unsigned long flags;
1565
1566 spin_lock_irqsave(q->queue_lock, flags);
1567
1568
1569
1570
1571
1572 smp_read_barrier_depends();
1573 if (cic->key)
1574 __cfq_exit_single_io_context(cfqd, cic);
1575
1576 spin_unlock_irqrestore(q->queue_lock, flags);
1577 }
1578}
1579
1580
1581
1582
1583
1584static void cfq_exit_io_context(struct io_context *ioc)
1585{
1586 call_for_each_cic(ioc, cfq_exit_single_io_context);
1587}
1588
1589static struct cfq_io_context *
1590cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask)
1591{
1592 struct cfq_io_context *cic;
1593
1594 cic = kmem_cache_alloc_node(cfq_ioc_pool, gfp_mask | __GFP_ZERO,
1595 cfqd->queue->node);
1596 if (cic) {
1597 cic->last_end_request = jiffies;
1598 INIT_LIST_HEAD(&cic->queue_list);
1599 INIT_HLIST_NODE(&cic->cic_list);
1600 cic->dtor = cfq_free_io_context;
1601 cic->exit = cfq_exit_io_context;
1602 elv_ioc_count_inc(cfq_ioc_count);
1603 }
1604
1605 return cic;
1606}
1607
1608static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc)
1609{
1610 struct task_struct *tsk = current;
1611 int ioprio_class;
1612
1613 if (!cfq_cfqq_prio_changed(cfqq))
1614 return;
1615
1616 ioprio_class = IOPRIO_PRIO_CLASS(ioc->ioprio);
1617 switch (ioprio_class) {
1618 default:
1619 printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class);
1620 case IOPRIO_CLASS_NONE:
1621
1622
1623
1624 cfqq->ioprio = task_nice_ioprio(tsk);
1625 cfqq->ioprio_class = task_nice_ioclass(tsk);
1626 break;
1627 case IOPRIO_CLASS_RT:
1628 cfqq->ioprio = task_ioprio(ioc);
1629 cfqq->ioprio_class = IOPRIO_CLASS_RT;
1630 break;
1631 case IOPRIO_CLASS_BE:
1632 cfqq->ioprio = task_ioprio(ioc);
1633 cfqq->ioprio_class = IOPRIO_CLASS_BE;
1634 break;
1635 case IOPRIO_CLASS_IDLE:
1636 cfqq->ioprio_class = IOPRIO_CLASS_IDLE;
1637 cfqq->ioprio = 7;
1638 cfq_clear_cfqq_idle_window(cfqq);
1639 break;
1640 }
1641
1642
1643
1644
1645
1646 cfqq->org_ioprio = cfqq->ioprio;
1647 cfqq->org_ioprio_class = cfqq->ioprio_class;
1648 cfq_clear_cfqq_prio_changed(cfqq);
1649}
1650
1651static void changed_ioprio(struct io_context *ioc, struct cfq_io_context *cic)
1652{
1653 struct cfq_data *cfqd = cic->key;
1654 struct cfq_queue *cfqq;
1655 unsigned long flags;
1656
1657 if (unlikely(!cfqd))
1658 return;
1659
1660 spin_lock_irqsave(cfqd->queue->queue_lock, flags);
1661
1662 cfqq = cic->cfqq[BLK_RW_ASYNC];
1663 if (cfqq) {
1664 struct cfq_queue *new_cfqq;
1665 new_cfqq = cfq_get_queue(cfqd, BLK_RW_ASYNC, cic->ioc,
1666 GFP_ATOMIC);
1667 if (new_cfqq) {
1668 cic->cfqq[BLK_RW_ASYNC] = new_cfqq;
1669 cfq_put_queue(cfqq);
1670 }
1671 }
1672
1673 cfqq = cic->cfqq[BLK_RW_SYNC];
1674 if (cfqq)
1675 cfq_mark_cfqq_prio_changed(cfqq);
1676
1677 spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
1678}
1679
1680static void cfq_ioc_set_ioprio(struct io_context *ioc)
1681{
1682 call_for_each_cic(ioc, changed_ioprio);
1683 ioc->ioprio_changed = 0;
1684}
1685
1686static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
1687 pid_t pid, bool is_sync)
1688{
1689 RB_CLEAR_NODE(&cfqq->rb_node);
1690 RB_CLEAR_NODE(&cfqq->p_node);
1691 INIT_LIST_HEAD(&cfqq->fifo);
1692
1693 atomic_set(&cfqq->ref, 0);
1694 cfqq->cfqd = cfqd;
1695
1696 cfq_mark_cfqq_prio_changed(cfqq);
1697
1698 if (is_sync) {
1699 if (!cfq_class_idle(cfqq))
1700 cfq_mark_cfqq_idle_window(cfqq);
1701 cfq_mark_cfqq_sync(cfqq);
1702 }
1703 cfqq->pid = pid;
1704}
1705
1706static struct cfq_queue *
1707cfq_find_alloc_queue(struct cfq_data *cfqd, bool is_sync,
1708 struct io_context *ioc, gfp_t gfp_mask)
1709{
1710 struct cfq_queue *cfqq, *new_cfqq = NULL;
1711 struct cfq_io_context *cic;
1712
1713retry:
1714 cic = cfq_cic_lookup(cfqd, ioc);
1715
1716 cfqq = cic_to_cfqq(cic, is_sync);
1717
1718
1719
1720
1721
1722 if (!cfqq || cfqq == &cfqd->oom_cfqq) {
1723 cfqq = NULL;
1724 if (new_cfqq) {
1725 cfqq = new_cfqq;
1726 new_cfqq = NULL;
1727 } else if (gfp_mask & __GFP_WAIT) {
1728 spin_unlock_irq(cfqd->queue->queue_lock);
1729 new_cfqq = kmem_cache_alloc_node(cfq_pool,
1730 gfp_mask | __GFP_ZERO,
1731 cfqd->queue->node);
1732 spin_lock_irq(cfqd->queue->queue_lock);
1733 if (new_cfqq)
1734 goto retry;
1735 } else {
1736 cfqq = kmem_cache_alloc_node(cfq_pool,
1737 gfp_mask | __GFP_ZERO,
1738 cfqd->queue->node);
1739 }
1740
1741 if (cfqq) {
1742 cfq_init_cfqq(cfqd, cfqq, current->pid, is_sync);
1743 cfq_init_prio_data(cfqq, ioc);
1744 cfq_log_cfqq(cfqd, cfqq, "alloced");
1745 } else
1746 cfqq = &cfqd->oom_cfqq;
1747 }
1748
1749 if (new_cfqq)
1750 kmem_cache_free(cfq_pool, new_cfqq);
1751
1752 return cfqq;
1753}
1754
1755static struct cfq_queue **
1756cfq_async_queue_prio(struct cfq_data *cfqd, int ioprio_class, int ioprio)
1757{
1758 switch (ioprio_class) {
1759 case IOPRIO_CLASS_RT:
1760 return &cfqd->async_cfqq[0][ioprio];
1761 case IOPRIO_CLASS_BE:
1762 return &cfqd->async_cfqq[1][ioprio];
1763 case IOPRIO_CLASS_IDLE:
1764 return &cfqd->async_idle_cfqq;
1765 default:
1766 BUG();
1767 }
1768}
1769
1770static struct cfq_queue *
1771cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct io_context *ioc,
1772 gfp_t gfp_mask)
1773{
1774 const int ioprio = task_ioprio(ioc);
1775 const int ioprio_class = task_ioprio_class(ioc);
1776 struct cfq_queue **async_cfqq = NULL;
1777 struct cfq_queue *cfqq = NULL;
1778
1779 if (!is_sync) {
1780 async_cfqq = cfq_async_queue_prio(cfqd, ioprio_class, ioprio);
1781 cfqq = *async_cfqq;
1782 }
1783
1784 if (!cfqq)
1785 cfqq = cfq_find_alloc_queue(cfqd, is_sync, ioc, gfp_mask);
1786
1787
1788
1789
1790 if (!is_sync && !(*async_cfqq)) {
1791 atomic_inc(&cfqq->ref);
1792 *async_cfqq = cfqq;
1793 }
1794
1795 atomic_inc(&cfqq->ref);
1796 return cfqq;
1797}
1798
1799
1800
1801
1802static void
1803cfq_drop_dead_cic(struct cfq_data *cfqd, struct io_context *ioc,
1804 struct cfq_io_context *cic)
1805{
1806 unsigned long flags;
1807
1808 WARN_ON(!list_empty(&cic->queue_list));
1809
1810 spin_lock_irqsave(&ioc->lock, flags);
1811
1812 BUG_ON(ioc->ioc_data == cic);
1813
1814 radix_tree_delete(&ioc->radix_root, (unsigned long) cfqd);
1815 hlist_del_rcu(&cic->cic_list);
1816 spin_unlock_irqrestore(&ioc->lock, flags);
1817
1818 cfq_cic_free(cic);
1819}
1820
1821static struct cfq_io_context *
1822cfq_cic_lookup(struct cfq_data *cfqd, struct io_context *ioc)
1823{
1824 struct cfq_io_context *cic;
1825 unsigned long flags;
1826 void *k;
1827
1828 if (unlikely(!ioc))
1829 return NULL;
1830
1831 rcu_read_lock();
1832
1833
1834
1835
1836 cic = rcu_dereference(ioc->ioc_data);
1837 if (cic && cic->key == cfqd) {
1838 rcu_read_unlock();
1839 return cic;
1840 }
1841
1842 do {
1843 cic = radix_tree_lookup(&ioc->radix_root, (unsigned long) cfqd);
1844 rcu_read_unlock();
1845 if (!cic)
1846 break;
1847
1848 k = cic->key;
1849 if (unlikely(!k)) {
1850 cfq_drop_dead_cic(cfqd, ioc, cic);
1851 rcu_read_lock();
1852 continue;
1853 }
1854
1855 spin_lock_irqsave(&ioc->lock, flags);
1856 rcu_assign_pointer(ioc->ioc_data, cic);
1857 spin_unlock_irqrestore(&ioc->lock, flags);
1858 break;
1859 } while (1);
1860
1861 return cic;
1862}
1863
1864
1865
1866
1867
1868
1869static int cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc,
1870 struct cfq_io_context *cic, gfp_t gfp_mask)
1871{
1872 unsigned long flags;
1873 int ret;
1874
1875 ret = radix_tree_preload(gfp_mask);
1876 if (!ret) {
1877 cic->ioc = ioc;
1878 cic->key = cfqd;
1879
1880 spin_lock_irqsave(&ioc->lock, flags);
1881 ret = radix_tree_insert(&ioc->radix_root,
1882 (unsigned long) cfqd, cic);
1883 if (!ret)
1884 hlist_add_head_rcu(&cic->cic_list, &ioc->cic_list);
1885 spin_unlock_irqrestore(&ioc->lock, flags);
1886
1887 radix_tree_preload_end();
1888
1889 if (!ret) {
1890 spin_lock_irqsave(cfqd->queue->queue_lock, flags);
1891 list_add(&cic->queue_list, &cfqd->cic_list);
1892 spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
1893 }
1894 }
1895
1896 if (ret)
1897 printk(KERN_ERR "cfq: cic link failed!\n");
1898
1899 return ret;
1900}
1901
1902
1903
1904
1905
1906
1907static struct cfq_io_context *
1908cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask)
1909{
1910 struct io_context *ioc = NULL;
1911 struct cfq_io_context *cic;
1912
1913 might_sleep_if(gfp_mask & __GFP_WAIT);
1914
1915 ioc = get_io_context(gfp_mask, cfqd->queue->node);
1916 if (!ioc)
1917 return NULL;
1918
1919 cic = cfq_cic_lookup(cfqd, ioc);
1920 if (cic)
1921 goto out;
1922
1923 cic = cfq_alloc_io_context(cfqd, gfp_mask);
1924 if (cic == NULL)
1925 goto err;
1926
1927 if (cfq_cic_link(cfqd, ioc, cic, gfp_mask))
1928 goto err_free;
1929
1930out:
1931 smp_read_barrier_depends();
1932 if (unlikely(ioc->ioprio_changed))
1933 cfq_ioc_set_ioprio(ioc);
1934
1935 return cic;
1936err_free:
1937 cfq_cic_free(cic);
1938err:
1939 put_io_context(ioc);
1940 return NULL;
1941}
1942
1943static void
1944cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic)
1945{
1946 unsigned long elapsed = jiffies - cic->last_end_request;
1947 unsigned long ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle);
1948
1949 cic->ttime_samples = (7*cic->ttime_samples + 256) / 8;
1950 cic->ttime_total = (7*cic->ttime_total + 256*ttime) / 8;
1951 cic->ttime_mean = (cic->ttime_total + 128) / cic->ttime_samples;
1952}
1953
1954static void
1955cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_io_context *cic,
1956 struct request *rq)
1957{
1958 sector_t sdist;
1959 u64 total;
1960
1961 if (!cic->last_request_pos)
1962 sdist = 0;
1963 else if (cic->last_request_pos < blk_rq_pos(rq))
1964 sdist = blk_rq_pos(rq) - cic->last_request_pos;
1965 else
1966 sdist = cic->last_request_pos - blk_rq_pos(rq);
1967
1968
1969
1970
1971
1972 if (cic->seek_samples <= 60)
1973 sdist = min(sdist, (cic->seek_mean * 4) + 2*1024*1024);
1974 else
1975 sdist = min(sdist, (cic->seek_mean * 4) + 2*1024*64);
1976
1977 cic->seek_samples = (7*cic->seek_samples + 256) / 8;
1978 cic->seek_total = (7*cic->seek_total + (u64)256*sdist) / 8;
1979 total = cic->seek_total + (cic->seek_samples/2);
1980 do_div(total, cic->seek_samples);
1981 cic->seek_mean = (sector_t)total;
1982}
1983
1984
1985
1986
1987
1988static void
1989cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
1990 struct cfq_io_context *cic)
1991{
1992 int old_idle, enable_idle;
1993
1994
1995
1996
1997 if (!cfq_cfqq_sync(cfqq) || cfq_class_idle(cfqq))
1998 return;
1999
2000 enable_idle = old_idle = cfq_cfqq_idle_window(cfqq);
2001
2002 if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle ||
2003 (!cfqd->cfq_latency && cfqd->hw_tag && CIC_SEEKY(cic)))
2004 enable_idle = 0;
2005 else if (sample_valid(cic->ttime_samples)) {
2006 unsigned int slice_idle = cfqd->cfq_slice_idle;
2007 if (sample_valid(cic->seek_samples) && CIC_SEEKY(cic))
2008 slice_idle = msecs_to_jiffies(CFQ_MIN_TT);
2009 if (cic->ttime_mean > slice_idle)
2010 enable_idle = 0;
2011 else
2012 enable_idle = 1;
2013 }
2014
2015 if (old_idle != enable_idle) {
2016 cfq_log_cfqq(cfqd, cfqq, "idle=%d", enable_idle);
2017 if (enable_idle)
2018 cfq_mark_cfqq_idle_window(cfqq);
2019 else
2020 cfq_clear_cfqq_idle_window(cfqq);
2021 }
2022}
2023
2024
2025
2026
2027
2028static bool
2029cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
2030 struct request *rq)
2031{
2032 struct cfq_queue *cfqq;
2033
2034 cfqq = cfqd->active_queue;
2035 if (!cfqq)
2036 return false;
2037
2038 if (cfq_slice_used(cfqq))
2039 return true;
2040
2041 if (cfq_class_idle(new_cfqq))
2042 return false;
2043
2044 if (cfq_class_idle(cfqq))
2045 return true;
2046
2047
2048
2049
2050
2051 if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq))
2052 return true;
2053
2054
2055
2056
2057
2058 if (rq_is_meta(rq) && !cfqq->meta_pending)
2059 return true;
2060
2061
2062
2063
2064 if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq))
2065 return true;
2066
2067 if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq))
2068 return false;
2069
2070
2071
2072
2073
2074 if (cfq_rq_close(cfqd, rq) && (!cfq_cfqq_coop(new_cfqq) ||
2075 cfqd->busy_queues == 1)) {
2076
2077
2078
2079
2080 cfq_mark_cfqq_coop_preempt(new_cfqq);
2081 cfq_mark_cfqq_coop(new_cfqq);
2082 return true;
2083 }
2084
2085 return false;
2086}
2087
2088
2089
2090
2091
2092static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
2093{
2094 cfq_log_cfqq(cfqd, cfqq, "preempt");
2095 cfq_slice_expired(cfqd, 1);
2096
2097
2098
2099
2100
2101 BUG_ON(!cfq_cfqq_on_rr(cfqq));
2102
2103 cfq_service_tree_add(cfqd, cfqq, 1);
2104
2105 cfqq->slice_end = 0;
2106 cfq_mark_cfqq_slice_new(cfqq);
2107}
2108
2109
2110
2111
2112
2113static void
2114cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
2115 struct request *rq)
2116{
2117 struct cfq_io_context *cic = RQ_CIC(rq);
2118
2119 cfqd->rq_queued++;
2120 if (rq_is_meta(rq))
2121 cfqq->meta_pending++;
2122
2123 cfq_update_io_thinktime(cfqd, cic);
2124 cfq_update_io_seektime(cfqd, cic, rq);
2125 cfq_update_idle_window(cfqd, cfqq, cic);
2126
2127 cic->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq);
2128
2129 if (cfqq == cfqd->active_queue) {
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140 if (cfq_cfqq_wait_request(cfqq)) {
2141 if (blk_rq_bytes(rq) > PAGE_CACHE_SIZE ||
2142 cfqd->busy_queues > 1) {
2143 del_timer(&cfqd->idle_slice_timer);
2144 __blk_run_queue(cfqd->queue);
2145 }
2146 cfq_mark_cfqq_must_dispatch(cfqq);
2147 }
2148 } else if (cfq_should_preempt(cfqd, cfqq, rq)) {
2149
2150
2151
2152
2153
2154
2155 cfq_preempt_queue(cfqd, cfqq);
2156 __blk_run_queue(cfqd->queue);
2157 }
2158}
2159
2160static void cfq_insert_request(struct request_queue *q, struct request *rq)
2161{
2162 struct cfq_data *cfqd = q->elevator->elevator_data;
2163 struct cfq_queue *cfqq = RQ_CFQQ(rq);
2164
2165 cfq_log_cfqq(cfqd, cfqq, "insert_request");
2166 cfq_init_prio_data(cfqq, RQ_CIC(rq)->ioc);
2167
2168 cfq_add_rq_rb(rq);
2169
2170 rq_set_fifo_time(rq, jiffies + cfqd->cfq_fifo_expire[rq_is_sync(rq)]);
2171 list_add_tail(&rq->queuelist, &cfqq->fifo);
2172
2173 cfq_rq_enqueued(cfqd, cfqq, rq);
2174}
2175
2176
2177
2178
2179
2180static void cfq_update_hw_tag(struct cfq_data *cfqd)
2181{
2182 if (rq_in_driver(cfqd) > cfqd->rq_in_driver_peak)
2183 cfqd->rq_in_driver_peak = rq_in_driver(cfqd);
2184
2185 if (cfqd->rq_queued <= CFQ_HW_QUEUE_MIN &&
2186 rq_in_driver(cfqd) <= CFQ_HW_QUEUE_MIN)
2187 return;
2188
2189 if (cfqd->hw_tag_samples++ < 50)
2190 return;
2191
2192 if (cfqd->rq_in_driver_peak >= CFQ_HW_QUEUE_MIN)
2193 cfqd->hw_tag = 1;
2194 else
2195 cfqd->hw_tag = 0;
2196
2197 cfqd->hw_tag_samples = 0;
2198 cfqd->rq_in_driver_peak = 0;
2199}
2200
2201static void cfq_completed_request(struct request_queue *q, struct request *rq)
2202{
2203 struct cfq_queue *cfqq = RQ_CFQQ(rq);
2204 struct cfq_data *cfqd = cfqq->cfqd;
2205 const int sync = rq_is_sync(rq);
2206 unsigned long now;
2207
2208 now = jiffies;
2209 cfq_log_cfqq(cfqd, cfqq, "complete");
2210
2211 cfq_update_hw_tag(cfqd);
2212
2213 WARN_ON(!cfqd->rq_in_driver[sync]);
2214 WARN_ON(!cfqq->dispatched);
2215 cfqd->rq_in_driver[sync]--;
2216 cfqq->dispatched--;
2217
2218 if (cfq_cfqq_sync(cfqq))
2219 cfqd->sync_flight--;
2220
2221 if (sync) {
2222 RQ_CIC(rq)->last_end_request = now;
2223 cfqd->last_end_sync_rq = now;
2224 }
2225
2226
2227
2228
2229
2230 if (cfqd->active_queue == cfqq) {
2231 const bool cfqq_empty = RB_EMPTY_ROOT(&cfqq->sort_list);
2232
2233 if (cfq_cfqq_slice_new(cfqq)) {
2234 cfq_set_prio_slice(cfqd, cfqq);
2235 cfq_clear_cfqq_slice_new(cfqq);
2236 }
2237
2238
2239
2240
2241
2242
2243
2244 if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq))
2245 cfq_slice_expired(cfqd, 1);
2246 else if (cfqq_empty && !cfq_close_cooperator(cfqd, cfqq, 1) &&
2247 sync && !rq_noidle(rq))
2248 cfq_arm_slice_timer(cfqd);
2249 }
2250
2251 if (!rq_in_driver(cfqd))
2252 cfq_schedule_dispatch(cfqd);
2253}
2254
2255
2256
2257
2258
2259static void cfq_prio_boost(struct cfq_queue *cfqq)
2260{
2261 if (has_fs_excl()) {
2262
2263
2264
2265
2266 if (cfq_class_idle(cfqq))
2267 cfqq->ioprio_class = IOPRIO_CLASS_BE;
2268 if (cfqq->ioprio > IOPRIO_NORM)
2269 cfqq->ioprio = IOPRIO_NORM;
2270 } else {
2271
2272
2273
2274 if (cfqq->ioprio_class != cfqq->org_ioprio_class)
2275 cfqq->ioprio_class = cfqq->org_ioprio_class;
2276 if (cfqq->ioprio != cfqq->org_ioprio)
2277 cfqq->ioprio = cfqq->org_ioprio;
2278 }
2279}
2280
2281static inline int __cfq_may_queue(struct cfq_queue *cfqq)
2282{
2283 if (cfq_cfqq_wait_request(cfqq) && !cfq_cfqq_must_alloc_slice(cfqq)) {
2284 cfq_mark_cfqq_must_alloc_slice(cfqq);
2285 return ELV_MQUEUE_MUST;
2286 }
2287
2288 return ELV_MQUEUE_MAY;
2289}
2290
2291static int cfq_may_queue(struct request_queue *q, int rw)
2292{
2293 struct cfq_data *cfqd = q->elevator->elevator_data;
2294 struct task_struct *tsk = current;
2295 struct cfq_io_context *cic;
2296 struct cfq_queue *cfqq;
2297
2298
2299
2300
2301
2302
2303
2304 cic = cfq_cic_lookup(cfqd, tsk->io_context);
2305 if (!cic)
2306 return ELV_MQUEUE_MAY;
2307
2308 cfqq = cic_to_cfqq(cic, rw_is_sync(rw));
2309 if (cfqq) {
2310 cfq_init_prio_data(cfqq, cic->ioc);
2311 cfq_prio_boost(cfqq);
2312
2313 return __cfq_may_queue(cfqq);
2314 }
2315
2316 return ELV_MQUEUE_MAY;
2317}
2318
2319
2320
2321
2322static void cfq_put_request(struct request *rq)
2323{
2324 struct cfq_queue *cfqq = RQ_CFQQ(rq);
2325
2326 if (cfqq) {
2327 const int rw = rq_data_dir(rq);
2328
2329 BUG_ON(!cfqq->allocated[rw]);
2330 cfqq->allocated[rw]--;
2331
2332 put_io_context(RQ_CIC(rq)->ioc);
2333
2334 rq->elevator_private = NULL;
2335 rq->elevator_private2 = NULL;
2336
2337 cfq_put_queue(cfqq);
2338 }
2339}
2340
2341
2342
2343
2344static int
2345cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask)
2346{
2347 struct cfq_data *cfqd = q->elevator->elevator_data;
2348 struct cfq_io_context *cic;
2349 const int rw = rq_data_dir(rq);
2350 const bool is_sync = rq_is_sync(rq);
2351 struct cfq_queue *cfqq;
2352 unsigned long flags;
2353
2354 might_sleep_if(gfp_mask & __GFP_WAIT);
2355
2356 cic = cfq_get_io_context(cfqd, gfp_mask);
2357
2358 spin_lock_irqsave(q->queue_lock, flags);
2359
2360 if (!cic)
2361 goto queue_fail;
2362
2363 cfqq = cic_to_cfqq(cic, is_sync);
2364 if (!cfqq || cfqq == &cfqd->oom_cfqq) {
2365 cfqq = cfq_get_queue(cfqd, is_sync, cic->ioc, gfp_mask);
2366 cic_set_cfqq(cic, cfqq, is_sync);
2367 }
2368
2369 cfqq->allocated[rw]++;
2370 atomic_inc(&cfqq->ref);
2371
2372 spin_unlock_irqrestore(q->queue_lock, flags);
2373
2374 rq->elevator_private = cic;
2375 rq->elevator_private2 = cfqq;
2376 return 0;
2377
2378queue_fail:
2379 if (cic)
2380 put_io_context(cic->ioc);
2381
2382 cfq_schedule_dispatch(cfqd);
2383 spin_unlock_irqrestore(q->queue_lock, flags);
2384 cfq_log(cfqd, "set_request fail");
2385 return 1;
2386}
2387
2388static void cfq_kick_queue(struct work_struct *work)
2389{
2390 struct cfq_data *cfqd =
2391 container_of(work, struct cfq_data, unplug_work);
2392 struct request_queue *q = cfqd->queue;
2393
2394 spin_lock_irq(q->queue_lock);
2395 __blk_run_queue(cfqd->queue);
2396 spin_unlock_irq(q->queue_lock);
2397}
2398
2399
2400
2401
2402static void cfq_idle_slice_timer(unsigned long data)
2403{
2404 struct cfq_data *cfqd = (struct cfq_data *) data;
2405 struct cfq_queue *cfqq;
2406 unsigned long flags;
2407 int timed_out = 1;
2408
2409 cfq_log(cfqd, "idle timer fired");
2410
2411 spin_lock_irqsave(cfqd->queue->queue_lock, flags);
2412
2413 cfqq = cfqd->active_queue;
2414 if (cfqq) {
2415 timed_out = 0;
2416
2417
2418
2419
2420 if (cfq_cfqq_must_dispatch(cfqq))
2421 goto out_kick;
2422
2423
2424
2425
2426 if (cfq_slice_used(cfqq))
2427 goto expire;
2428
2429
2430
2431
2432
2433 if (!cfqd->busy_queues)
2434 goto out_cont;
2435
2436
2437
2438
2439 if (!RB_EMPTY_ROOT(&cfqq->sort_list))
2440 goto out_kick;
2441 }
2442expire:
2443 cfq_slice_expired(cfqd, timed_out);
2444out_kick:
2445 cfq_schedule_dispatch(cfqd);
2446out_cont:
2447 spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
2448}
2449
2450static void cfq_shutdown_timer_wq(struct cfq_data *cfqd)
2451{
2452 del_timer_sync(&cfqd->idle_slice_timer);
2453 cancel_work_sync(&cfqd->unplug_work);
2454}
2455
2456static void cfq_put_async_queues(struct cfq_data *cfqd)
2457{
2458 int i;
2459
2460 for (i = 0; i < IOPRIO_BE_NR; i++) {
2461 if (cfqd->async_cfqq[0][i])
2462 cfq_put_queue(cfqd->async_cfqq[0][i]);
2463 if (cfqd->async_cfqq[1][i])
2464 cfq_put_queue(cfqd->async_cfqq[1][i]);
2465 }
2466
2467 if (cfqd->async_idle_cfqq)
2468 cfq_put_queue(cfqd->async_idle_cfqq);
2469}
2470
2471static void cfq_exit_queue(struct elevator_queue *e)
2472{
2473 struct cfq_data *cfqd = e->elevator_data;
2474 struct request_queue *q = cfqd->queue;
2475
2476 cfq_shutdown_timer_wq(cfqd);
2477
2478 spin_lock_irq(q->queue_lock);
2479
2480 if (cfqd->active_queue)
2481 __cfq_slice_expired(cfqd, cfqd->active_queue, 0);
2482
2483 while (!list_empty(&cfqd->cic_list)) {
2484 struct cfq_io_context *cic = list_entry(cfqd->cic_list.next,
2485 struct cfq_io_context,
2486 queue_list);
2487
2488 __cfq_exit_single_io_context(cfqd, cic);
2489 }
2490
2491 cfq_put_async_queues(cfqd);
2492
2493 spin_unlock_irq(q->queue_lock);
2494
2495 cfq_shutdown_timer_wq(cfqd);
2496
2497 kfree(cfqd);
2498}
2499
2500static void *cfq_init_queue(struct request_queue *q)
2501{
2502 struct cfq_data *cfqd;
2503 int i;
2504
2505 cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL | __GFP_ZERO, q->node);
2506 if (!cfqd)
2507 return NULL;
2508
2509 cfqd->service_tree = CFQ_RB_ROOT;
2510
2511
2512
2513
2514
2515
2516 for (i = 0; i < CFQ_PRIO_LISTS; i++)
2517 cfqd->prio_trees[i] = RB_ROOT;
2518
2519
2520
2521
2522
2523
2524 cfq_init_cfqq(cfqd, &cfqd->oom_cfqq, 1, 0);
2525 atomic_inc(&cfqd->oom_cfqq.ref);
2526
2527 INIT_LIST_HEAD(&cfqd->cic_list);
2528
2529 cfqd->queue = q;
2530
2531 init_timer(&cfqd->idle_slice_timer);
2532 cfqd->idle_slice_timer.function = cfq_idle_slice_timer;
2533 cfqd->idle_slice_timer.data = (unsigned long) cfqd;
2534
2535 INIT_WORK(&cfqd->unplug_work, cfq_kick_queue);
2536
2537 cfqd->cfq_quantum = cfq_quantum;
2538 cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0];
2539 cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1];
2540 cfqd->cfq_back_max = cfq_back_max;
2541 cfqd->cfq_back_penalty = cfq_back_penalty;
2542 cfqd->cfq_slice[0] = cfq_slice_async;
2543 cfqd->cfq_slice[1] = cfq_slice_sync;
2544 cfqd->cfq_slice_async_rq = cfq_slice_async_rq;
2545 cfqd->cfq_slice_idle = cfq_slice_idle;
2546 cfqd->cfq_latency = 1;
2547 cfqd->hw_tag = 1;
2548 cfqd->last_end_sync_rq = jiffies;
2549 return cfqd;
2550}
2551
2552static void cfq_slab_kill(void)
2553{
2554
2555
2556
2557
2558 if (cfq_pool)
2559 kmem_cache_destroy(cfq_pool);
2560 if (cfq_ioc_pool)
2561 kmem_cache_destroy(cfq_ioc_pool);
2562}
2563
2564static int __init cfq_slab_setup(void)
2565{
2566 cfq_pool = KMEM_CACHE(cfq_queue, 0);
2567 if (!cfq_pool)
2568 goto fail;
2569
2570 cfq_ioc_pool = KMEM_CACHE(cfq_io_context, 0);
2571 if (!cfq_ioc_pool)
2572 goto fail;
2573
2574 return 0;
2575fail:
2576 cfq_slab_kill();
2577 return -ENOMEM;
2578}
2579
2580
2581
2582
2583static ssize_t
2584cfq_var_show(unsigned int var, char *page)
2585{
2586 return sprintf(page, "%d\n", var);
2587}
2588
2589static ssize_t
2590cfq_var_store(unsigned int *var, const char *page, size_t count)
2591{
2592 char *p = (char *) page;
2593
2594 *var = simple_strtoul(p, &p, 10);
2595 return count;
2596}
2597
2598#define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \
2599static ssize_t __FUNC(struct elevator_queue *e, char *page) \
2600{ \
2601 struct cfq_data *cfqd = e->elevator_data; \
2602 unsigned int __data = __VAR; \
2603 if (__CONV) \
2604 __data = jiffies_to_msecs(__data); \
2605 return cfq_var_show(__data, (page)); \
2606}
2607SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0);
2608SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1);
2609SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1);
2610SHOW_FUNCTION(cfq_back_seek_max_show, cfqd->cfq_back_max, 0);
2611SHOW_FUNCTION(cfq_back_seek_penalty_show, cfqd->cfq_back_penalty, 0);
2612SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1);
2613SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1);
2614SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1);
2615SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0);
2616SHOW_FUNCTION(cfq_low_latency_show, cfqd->cfq_latency, 0);
2617#undef SHOW_FUNCTION
2618
2619#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \
2620static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \
2621{ \
2622 struct cfq_data *cfqd = e->elevator_data; \
2623 unsigned int __data; \
2624 int ret = cfq_var_store(&__data, (page), count); \
2625 if (__data < (MIN)) \
2626 __data = (MIN); \
2627 else if (__data > (MAX)) \
2628 __data = (MAX); \
2629 if (__CONV) \
2630 *(__PTR) = msecs_to_jiffies(__data); \
2631 else \
2632 *(__PTR) = __data; \
2633 return ret; \
2634}
2635STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0);
2636STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1,
2637 UINT_MAX, 1);
2638STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1,
2639 UINT_MAX, 1);
2640STORE_FUNCTION(cfq_back_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0);
2641STORE_FUNCTION(cfq_back_seek_penalty_store, &cfqd->cfq_back_penalty, 1,
2642 UINT_MAX, 0);
2643STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1);
2644STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1);
2645STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1);
2646STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1,
2647 UINT_MAX, 0);
2648STORE_FUNCTION(cfq_low_latency_store, &cfqd->cfq_latency, 0, 1, 0);
2649#undef STORE_FUNCTION
2650
2651#define CFQ_ATTR(name) \
2652 __ATTR(name, S_IRUGO|S_IWUSR, cfq_##name##_show, cfq_##name##_store)
2653
2654static struct elv_fs_entry cfq_attrs[] = {
2655 CFQ_ATTR(quantum),
2656 CFQ_ATTR(fifo_expire_sync),
2657 CFQ_ATTR(fifo_expire_async),
2658 CFQ_ATTR(back_seek_max),
2659 CFQ_ATTR(back_seek_penalty),
2660 CFQ_ATTR(slice_sync),
2661 CFQ_ATTR(slice_async),
2662 CFQ_ATTR(slice_async_rq),
2663 CFQ_ATTR(slice_idle),
2664 CFQ_ATTR(low_latency),
2665 __ATTR_NULL
2666};
2667
2668static struct elevator_type iosched_cfq = {
2669 .ops = {
2670 .elevator_merge_fn = cfq_merge,
2671 .elevator_merged_fn = cfq_merged_request,
2672 .elevator_merge_req_fn = cfq_merged_requests,
2673 .elevator_allow_merge_fn = cfq_allow_merge,
2674 .elevator_dispatch_fn = cfq_dispatch_requests,
2675 .elevator_add_req_fn = cfq_insert_request,
2676 .elevator_activate_req_fn = cfq_activate_request,
2677 .elevator_deactivate_req_fn = cfq_deactivate_request,
2678 .elevator_queue_empty_fn = cfq_queue_empty,
2679 .elevator_completed_req_fn = cfq_completed_request,
2680 .elevator_former_req_fn = elv_rb_former_request,
2681 .elevator_latter_req_fn = elv_rb_latter_request,
2682 .elevator_set_req_fn = cfq_set_request,
2683 .elevator_put_req_fn = cfq_put_request,
2684 .elevator_may_queue_fn = cfq_may_queue,
2685 .elevator_init_fn = cfq_init_queue,
2686 .elevator_exit_fn = cfq_exit_queue,
2687 .trim = cfq_free_io_context,
2688 },
2689 .elevator_attrs = cfq_attrs,
2690 .elevator_name = "cfq",
2691 .elevator_owner = THIS_MODULE,
2692};
2693
2694static int __init cfq_init(void)
2695{
2696
2697
2698
2699 if (!cfq_slice_async)
2700 cfq_slice_async = 1;
2701 if (!cfq_slice_idle)
2702 cfq_slice_idle = 1;
2703
2704 if (cfq_slab_setup())
2705 return -ENOMEM;
2706
2707 elv_register(&iosched_cfq);
2708
2709 return 0;
2710}
2711
2712static void __exit cfq_exit(void)
2713{
2714 DECLARE_COMPLETION_ONSTACK(all_gone);
2715 elv_unregister(&iosched_cfq);
2716 ioc_gone = &all_gone;
2717
2718 smp_wmb();
2719
2720
2721
2722
2723
2724 if (elv_ioc_count_read(cfq_ioc_count))
2725 wait_for_completion(&all_gone);
2726 cfq_slab_kill();
2727}
2728
2729module_init(cfq_init);
2730module_exit(cfq_exit);
2731
2732MODULE_AUTHOR("Jens Axboe");
2733MODULE_LICENSE("GPL");
2734MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler");
2735