2 * CFQ, or complete fairness queueing, disk scheduler.
4 * Based on ideas from a previously unfinished io
5 * scheduler (round robin per-process disk scheduling) and Andrea Arcangeli.
7 * Copyright (C) 2003 Jens Axboe <axboe@suse.de>
9 #include <linux/config.h>
10 #include <linux/module.h>
11 #include <linux/blkdev.h>
12 #include <linux/elevator.h>
13 #include <linux/hash.h>
14 #include <linux/rbtree.h>
15 #include <linux/ioprio.h>
20 static const int cfq_quantum
= 4; /* max queue in one round of service */
21 static const int cfq_queued
= 8; /* minimum rq allocate limit per-queue*/
22 static const int cfq_fifo_expire
[2] = { HZ
/ 4, HZ
/ 8 };
23 static const int cfq_back_max
= 16 * 1024; /* maximum backwards seek, in KiB */
24 static const int cfq_back_penalty
= 2; /* penalty of a backwards seek */
26 static const int cfq_slice_sync
= HZ
/ 10;
27 static int cfq_slice_async
= HZ
/ 25;
28 static const int cfq_slice_async_rq
= 2;
29 static int cfq_slice_idle
= HZ
/ 100;
31 #define CFQ_IDLE_GRACE (HZ / 10)
32 #define CFQ_SLICE_SCALE (5)
34 #define CFQ_KEY_ASYNC (0)
35 #define CFQ_KEY_ANY (0xffff)
38 * disable queueing at the driver/hardware level
40 static const int cfq_max_depth
= 2;
42 static DEFINE_RWLOCK(cfq_exit_lock
);
45 * for the hash of cfqq inside the cfqd
47 #define CFQ_QHASH_SHIFT 6
48 #define CFQ_QHASH_ENTRIES (1 << CFQ_QHASH_SHIFT)
49 #define list_entry_qhash(entry) hlist_entry((entry), struct cfq_queue, cfq_hash)
52 * for the hash of crq inside the cfqq
54 #define CFQ_MHASH_SHIFT 6
55 #define CFQ_MHASH_BLOCK(sec) ((sec) >> 3)
56 #define CFQ_MHASH_ENTRIES (1 << CFQ_MHASH_SHIFT)
57 #define CFQ_MHASH_FN(sec) hash_long(CFQ_MHASH_BLOCK(sec), CFQ_MHASH_SHIFT)
58 #define rq_hash_key(rq) ((rq)->sector + (rq)->nr_sectors)
59 #define list_entry_hash(ptr) hlist_entry((ptr), struct cfq_rq, hash)
61 #define list_entry_cfqq(ptr) list_entry((ptr), struct cfq_queue, cfq_list)
62 #define list_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
64 #define RQ_DATA(rq) (rq)->elevator_private
70 #define RB_EMPTY(node) ((node)->rb_node == NULL)
71 #define RB_CLEAR_COLOR(node) (node)->rb_color = RB_NONE
72 #define RB_CLEAR(node) do { \
73 (node)->rb_parent = NULL; \
74 RB_CLEAR_COLOR((node)); \
75 (node)->rb_right = NULL; \
76 (node)->rb_left = NULL; \
78 #define RB_CLEAR_ROOT(root) ((root)->rb_node = NULL)
79 #define rb_entry_crq(node) rb_entry((node), struct cfq_rq, rb_node)
80 #define rq_rb_key(rq) (rq)->sector
82 static kmem_cache_t
*crq_pool
;
83 static kmem_cache_t
*cfq_pool
;
84 static kmem_cache_t
*cfq_ioc_pool
;
86 static atomic_t ioc_count
= ATOMIC_INIT(0);
87 static struct completion
*ioc_gone
;
89 #define CFQ_PRIO_LISTS IOPRIO_BE_NR
90 #define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE)
91 #define cfq_class_be(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_BE)
92 #define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT)
97 #define cfq_cfqq_dispatched(cfqq) \
98 ((cfqq)->on_dispatch[ASYNC] + (cfqq)->on_dispatch[SYNC])
100 #define cfq_cfqq_class_sync(cfqq) ((cfqq)->key != CFQ_KEY_ASYNC)
102 #define cfq_cfqq_sync(cfqq) \
103 (cfq_cfqq_class_sync(cfqq) || (cfqq)->on_dispatch[SYNC])
106 * Per block device queue structure
109 request_queue_t
*queue
;
112 * rr list of queues with requests and the count of them
114 struct list_head rr_list
[CFQ_PRIO_LISTS
];
115 struct list_head busy_rr
;
116 struct list_head cur_rr
;
117 struct list_head idle_rr
;
118 unsigned int busy_queues
;
121 * non-ordered list of empty cfqq's
123 struct list_head empty_list
;
128 struct hlist_head
*cfq_hash
;
131 * global crq hash for all queues
133 struct hlist_head
*crq_hash
;
135 unsigned int max_queued
;
142 * schedule slice state info
145 * idle window management
147 struct timer_list idle_slice_timer
;
148 struct work_struct unplug_work
;
150 struct cfq_queue
*active_queue
;
151 struct cfq_io_context
*active_cic
;
152 int cur_prio
, cur_end_prio
;
153 unsigned int dispatch_slice
;
155 struct timer_list idle_class_timer
;
157 sector_t last_sector
;
158 unsigned long last_end_request
;
160 unsigned int rq_starved
;
163 * tunables, see top of file
165 unsigned int cfq_quantum
;
166 unsigned int cfq_queued
;
167 unsigned int cfq_fifo_expire
[2];
168 unsigned int cfq_back_penalty
;
169 unsigned int cfq_back_max
;
170 unsigned int cfq_slice
[2];
171 unsigned int cfq_slice_async_rq
;
172 unsigned int cfq_slice_idle
;
173 unsigned int cfq_max_depth
;
175 struct list_head cic_list
;
179 * Per process-grouping structure
182 /* reference count */
184 /* parent cfq_data */
185 struct cfq_data
*cfqd
;
186 /* cfqq lookup hash */
187 struct hlist_node cfq_hash
;
190 /* on either rr or empty list of cfqd */
191 struct list_head cfq_list
;
192 /* sorted list of pending requests */
193 struct rb_root sort_list
;
194 /* if fifo isn't expired, next request to serve */
195 struct cfq_rq
*next_crq
;
196 /* requests queued in sort_list */
198 /* currently allocated requests */
200 /* fifo list of requests in sort_list */
201 struct list_head fifo
;
203 unsigned long slice_start
;
204 unsigned long slice_end
;
205 unsigned long slice_left
;
206 unsigned long service_last
;
208 /* number of requests that are on the dispatch list */
211 /* io prio of this group */
212 unsigned short ioprio
, org_ioprio
;
213 unsigned short ioprio_class
, org_ioprio_class
;
215 /* various state flags, see below */
220 struct rb_node rb_node
;
222 struct request
*request
;
223 struct hlist_node hash
;
225 struct cfq_queue
*cfq_queue
;
226 struct cfq_io_context
*io_context
;
228 unsigned int crq_flags
;
231 enum cfqq_state_flags
{
232 CFQ_CFQQ_FLAG_on_rr
= 0,
233 CFQ_CFQQ_FLAG_wait_request
,
234 CFQ_CFQQ_FLAG_must_alloc
,
235 CFQ_CFQQ_FLAG_must_alloc_slice
,
236 CFQ_CFQQ_FLAG_must_dispatch
,
237 CFQ_CFQQ_FLAG_fifo_expire
,
238 CFQ_CFQQ_FLAG_idle_window
,
239 CFQ_CFQQ_FLAG_prio_changed
,
242 #define CFQ_CFQQ_FNS(name) \
243 static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \
245 cfqq->flags |= (1 << CFQ_CFQQ_FLAG_##name); \
247 static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \
249 cfqq->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \
251 static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \
253 return (cfqq->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \
257 CFQ_CFQQ_FNS(wait_request
);
258 CFQ_CFQQ_FNS(must_alloc
);
259 CFQ_CFQQ_FNS(must_alloc_slice
);
260 CFQ_CFQQ_FNS(must_dispatch
);
261 CFQ_CFQQ_FNS(fifo_expire
);
262 CFQ_CFQQ_FNS(idle_window
);
263 CFQ_CFQQ_FNS(prio_changed
);
266 enum cfq_rq_state_flags
{
267 CFQ_CRQ_FLAG_is_sync
= 0,
270 #define CFQ_CRQ_FNS(name) \
271 static inline void cfq_mark_crq_##name(struct cfq_rq *crq) \
273 crq->crq_flags |= (1 << CFQ_CRQ_FLAG_##name); \
275 static inline void cfq_clear_crq_##name(struct cfq_rq *crq) \
277 crq->crq_flags &= ~(1 << CFQ_CRQ_FLAG_##name); \
279 static inline int cfq_crq_##name(const struct cfq_rq *crq) \
281 return (crq->crq_flags & (1 << CFQ_CRQ_FLAG_##name)) != 0; \
284 CFQ_CRQ_FNS(is_sync
);
287 static struct cfq_queue
*cfq_find_cfq_hash(struct cfq_data
*, unsigned int, unsigned short);
288 static void cfq_dispatch_insert(request_queue_t
*, struct cfq_rq
*);
289 static struct cfq_queue
*cfq_get_queue(struct cfq_data
*cfqd
, unsigned int key
, struct task_struct
*tsk
, gfp_t gfp_mask
);
291 #define process_sync(tsk) ((tsk)->flags & PF_SYNCWRITE)
294 * lots of deadline iosched dupes, can be abstracted later...
296 static inline void cfq_del_crq_hash(struct cfq_rq
*crq
)
298 hlist_del_init(&crq
->hash
);
301 static inline void cfq_add_crq_hash(struct cfq_data
*cfqd
, struct cfq_rq
*crq
)
303 const int hash_idx
= CFQ_MHASH_FN(rq_hash_key(crq
->request
));
305 hlist_add_head(&crq
->hash
, &cfqd
->crq_hash
[hash_idx
]);
308 static struct request
*cfq_find_rq_hash(struct cfq_data
*cfqd
, sector_t offset
)
310 struct hlist_head
*hash_list
= &cfqd
->crq_hash
[CFQ_MHASH_FN(offset
)];
311 struct hlist_node
*entry
, *next
;
313 hlist_for_each_safe(entry
, next
, hash_list
) {
314 struct cfq_rq
*crq
= list_entry_hash(entry
);
315 struct request
*__rq
= crq
->request
;
317 if (!rq_mergeable(__rq
)) {
318 cfq_del_crq_hash(crq
);
322 if (rq_hash_key(__rq
) == offset
)
330 * scheduler run of queue, if there are requests pending and no one in the
331 * driver that will restart queueing
333 static inline void cfq_schedule_dispatch(struct cfq_data
*cfqd
)
335 if (cfqd
->busy_queues
)
336 kblockd_schedule_work(&cfqd
->unplug_work
);
339 static int cfq_queue_empty(request_queue_t
*q
)
341 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
343 return !cfqd
->busy_queues
;
347 * Lifted from AS - choose which of crq1 and crq2 that is best served now.
348 * We choose the request that is closest to the head right now. Distance
349 * behind the head are penalized and only allowed to a certain extent.
351 static struct cfq_rq
*
352 cfq_choose_req(struct cfq_data
*cfqd
, struct cfq_rq
*crq1
, struct cfq_rq
*crq2
)
354 sector_t last
, s1
, s2
, d1
= 0, d2
= 0;
355 int r1_wrap
= 0, r2_wrap
= 0; /* requests are behind the disk head */
356 unsigned long back_max
;
358 if (crq1
== NULL
|| crq1
== crq2
)
363 if (cfq_crq_is_sync(crq1
) && !cfq_crq_is_sync(crq2
))
365 else if (cfq_crq_is_sync(crq2
) && !cfq_crq_is_sync(crq1
))
368 s1
= crq1
->request
->sector
;
369 s2
= crq2
->request
->sector
;
371 last
= cfqd
->last_sector
;
374 * by definition, 1KiB is 2 sectors
376 back_max
= cfqd
->cfq_back_max
* 2;
379 * Strict one way elevator _except_ in the case where we allow
380 * short backward seeks which are biased as twice the cost of a
381 * similar forward seek.
385 else if (s1
+ back_max
>= last
)
386 d1
= (last
- s1
) * cfqd
->cfq_back_penalty
;
392 else if (s2
+ back_max
>= last
)
393 d2
= (last
- s2
) * cfqd
->cfq_back_penalty
;
397 /* Found required data */
398 if (!r1_wrap
&& r2_wrap
)
400 else if (!r2_wrap
&& r1_wrap
)
402 else if (r1_wrap
&& r2_wrap
) {
403 /* both behind the head */
410 /* Both requests in front of the head */
424 * would be nice to take fifo expire time into account as well
426 static struct cfq_rq
*
427 cfq_find_next_crq(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
430 struct cfq_rq
*crq_next
= NULL
, *crq_prev
= NULL
;
431 struct rb_node
*rbnext
, *rbprev
;
433 if (!(rbnext
= rb_next(&last
->rb_node
))) {
434 rbnext
= rb_first(&cfqq
->sort_list
);
435 if (rbnext
== &last
->rb_node
)
439 rbprev
= rb_prev(&last
->rb_node
);
442 crq_prev
= rb_entry_crq(rbprev
);
444 crq_next
= rb_entry_crq(rbnext
);
446 return cfq_choose_req(cfqd
, crq_next
, crq_prev
);
449 static void cfq_update_next_crq(struct cfq_rq
*crq
)
451 struct cfq_queue
*cfqq
= crq
->cfq_queue
;
453 if (cfqq
->next_crq
== crq
)
454 cfqq
->next_crq
= cfq_find_next_crq(cfqq
->cfqd
, cfqq
, crq
);
457 static void cfq_resort_rr_list(struct cfq_queue
*cfqq
, int preempted
)
459 struct cfq_data
*cfqd
= cfqq
->cfqd
;
460 struct list_head
*list
, *entry
;
462 BUG_ON(!cfq_cfqq_on_rr(cfqq
));
464 list_del(&cfqq
->cfq_list
);
466 if (cfq_class_rt(cfqq
))
467 list
= &cfqd
->cur_rr
;
468 else if (cfq_class_idle(cfqq
))
469 list
= &cfqd
->idle_rr
;
472 * if cfqq has requests in flight, don't allow it to be
473 * found in cfq_set_active_queue before it has finished them.
474 * this is done to increase fairness between a process that
475 * has lots of io pending vs one that only generates one
476 * sporadically or synchronously
478 if (cfq_cfqq_dispatched(cfqq
))
479 list
= &cfqd
->busy_rr
;
481 list
= &cfqd
->rr_list
[cfqq
->ioprio
];
485 * if queue was preempted, just add to front to be fair. busy_rr
488 if (preempted
|| list
== &cfqd
->busy_rr
) {
489 list_add(&cfqq
->cfq_list
, list
);
494 * sort by when queue was last serviced
497 while ((entry
= entry
->prev
) != list
) {
498 struct cfq_queue
*__cfqq
= list_entry_cfqq(entry
);
500 if (!__cfqq
->service_last
)
502 if (time_before(__cfqq
->service_last
, cfqq
->service_last
))
506 list_add(&cfqq
->cfq_list
, entry
);
510 * add to busy list of queues for service, trying to be fair in ordering
511 * the pending list according to last request service
514 cfq_add_cfqq_rr(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
516 BUG_ON(cfq_cfqq_on_rr(cfqq
));
517 cfq_mark_cfqq_on_rr(cfqq
);
520 cfq_resort_rr_list(cfqq
, 0);
524 cfq_del_cfqq_rr(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
526 BUG_ON(!cfq_cfqq_on_rr(cfqq
));
527 cfq_clear_cfqq_on_rr(cfqq
);
528 list_move(&cfqq
->cfq_list
, &cfqd
->empty_list
);
530 BUG_ON(!cfqd
->busy_queues
);
535 * rb tree support functions
537 static inline void cfq_del_crq_rb(struct cfq_rq
*crq
)
539 struct cfq_queue
*cfqq
= crq
->cfq_queue
;
540 struct cfq_data
*cfqd
= cfqq
->cfqd
;
541 const int sync
= cfq_crq_is_sync(crq
);
543 BUG_ON(!cfqq
->queued
[sync
]);
544 cfqq
->queued
[sync
]--;
546 cfq_update_next_crq(crq
);
548 rb_erase(&crq
->rb_node
, &cfqq
->sort_list
);
549 RB_CLEAR_COLOR(&crq
->rb_node
);
551 if (cfq_cfqq_on_rr(cfqq
) && RB_EMPTY(&cfqq
->sort_list
))
552 cfq_del_cfqq_rr(cfqd
, cfqq
);
555 static struct cfq_rq
*
556 __cfq_add_crq_rb(struct cfq_rq
*crq
)
558 struct rb_node
**p
= &crq
->cfq_queue
->sort_list
.rb_node
;
559 struct rb_node
*parent
= NULL
;
560 struct cfq_rq
*__crq
;
564 __crq
= rb_entry_crq(parent
);
566 if (crq
->rb_key
< __crq
->rb_key
)
568 else if (crq
->rb_key
> __crq
->rb_key
)
574 rb_link_node(&crq
->rb_node
, parent
, p
);
578 static void cfq_add_crq_rb(struct cfq_rq
*crq
)
580 struct cfq_queue
*cfqq
= crq
->cfq_queue
;
581 struct cfq_data
*cfqd
= cfqq
->cfqd
;
582 struct request
*rq
= crq
->request
;
583 struct cfq_rq
*__alias
;
585 crq
->rb_key
= rq_rb_key(rq
);
586 cfqq
->queued
[cfq_crq_is_sync(crq
)]++;
589 * looks a little odd, but the first insert might return an alias.
590 * if that happens, put the alias on the dispatch list
592 while ((__alias
= __cfq_add_crq_rb(crq
)) != NULL
)
593 cfq_dispatch_insert(cfqd
->queue
, __alias
);
595 rb_insert_color(&crq
->rb_node
, &cfqq
->sort_list
);
597 if (!cfq_cfqq_on_rr(cfqq
))
598 cfq_add_cfqq_rr(cfqd
, cfqq
);
601 * check if this request is a better next-serve candidate
603 cfqq
->next_crq
= cfq_choose_req(cfqd
, cfqq
->next_crq
, crq
);
607 cfq_reposition_crq_rb(struct cfq_queue
*cfqq
, struct cfq_rq
*crq
)
609 rb_erase(&crq
->rb_node
, &cfqq
->sort_list
);
610 cfqq
->queued
[cfq_crq_is_sync(crq
)]--;
615 static struct request
*cfq_find_rq_rb(struct cfq_data
*cfqd
, sector_t sector
)
618 struct cfq_queue
*cfqq
= cfq_find_cfq_hash(cfqd
, current
->pid
, CFQ_KEY_ANY
);
624 n
= cfqq
->sort_list
.rb_node
;
626 struct cfq_rq
*crq
= rb_entry_crq(n
);
628 if (sector
< crq
->rb_key
)
630 else if (sector
> crq
->rb_key
)
640 static void cfq_activate_request(request_queue_t
*q
, struct request
*rq
)
642 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
644 cfqd
->rq_in_driver
++;
647 static void cfq_deactivate_request(request_queue_t
*q
, struct request
*rq
)
649 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
651 WARN_ON(!cfqd
->rq_in_driver
);
652 cfqd
->rq_in_driver
--;
655 static void cfq_remove_request(struct request
*rq
)
657 struct cfq_rq
*crq
= RQ_DATA(rq
);
659 list_del_init(&rq
->queuelist
);
661 cfq_del_crq_hash(crq
);
665 cfq_merge(request_queue_t
*q
, struct request
**req
, struct bio
*bio
)
667 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
668 struct request
*__rq
;
671 __rq
= cfq_find_rq_hash(cfqd
, bio
->bi_sector
);
672 if (__rq
&& elv_rq_merge_ok(__rq
, bio
)) {
673 ret
= ELEVATOR_BACK_MERGE
;
677 __rq
= cfq_find_rq_rb(cfqd
, bio
->bi_sector
+ bio_sectors(bio
));
678 if (__rq
&& elv_rq_merge_ok(__rq
, bio
)) {
679 ret
= ELEVATOR_FRONT_MERGE
;
683 return ELEVATOR_NO_MERGE
;
689 static void cfq_merged_request(request_queue_t
*q
, struct request
*req
)
691 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
692 struct cfq_rq
*crq
= RQ_DATA(req
);
694 cfq_del_crq_hash(crq
);
695 cfq_add_crq_hash(cfqd
, crq
);
697 if (rq_rb_key(req
) != crq
->rb_key
) {
698 struct cfq_queue
*cfqq
= crq
->cfq_queue
;
700 cfq_update_next_crq(crq
);
701 cfq_reposition_crq_rb(cfqq
, crq
);
706 cfq_merged_requests(request_queue_t
*q
, struct request
*rq
,
707 struct request
*next
)
709 cfq_merged_request(q
, rq
);
712 * reposition in fifo if next is older than rq
714 if (!list_empty(&rq
->queuelist
) && !list_empty(&next
->queuelist
) &&
715 time_before(next
->start_time
, rq
->start_time
))
716 list_move(&rq
->queuelist
, &next
->queuelist
);
718 cfq_remove_request(next
);
722 __cfq_set_active_queue(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
726 * stop potential idle class queues waiting service
728 del_timer(&cfqd
->idle_class_timer
);
730 cfqq
->slice_start
= jiffies
;
732 cfqq
->slice_left
= 0;
733 cfq_clear_cfqq_must_alloc_slice(cfqq
);
734 cfq_clear_cfqq_fifo_expire(cfqq
);
737 cfqd
->active_queue
= cfqq
;
741 * current cfqq expired its slice (or was too idle), select new one
744 __cfq_slice_expired(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
747 unsigned long now
= jiffies
;
749 if (cfq_cfqq_wait_request(cfqq
))
750 del_timer(&cfqd
->idle_slice_timer
);
752 if (!preempted
&& !cfq_cfqq_dispatched(cfqq
)) {
753 cfqq
->service_last
= now
;
754 cfq_schedule_dispatch(cfqd
);
757 cfq_clear_cfqq_must_dispatch(cfqq
);
758 cfq_clear_cfqq_wait_request(cfqq
);
761 * store what was left of this slice, if the queue idled out
764 if (time_after(cfqq
->slice_end
, now
))
765 cfqq
->slice_left
= cfqq
->slice_end
- now
;
767 cfqq
->slice_left
= 0;
769 if (cfq_cfqq_on_rr(cfqq
))
770 cfq_resort_rr_list(cfqq
, preempted
);
772 if (cfqq
== cfqd
->active_queue
)
773 cfqd
->active_queue
= NULL
;
775 if (cfqd
->active_cic
) {
776 put_io_context(cfqd
->active_cic
->ioc
);
777 cfqd
->active_cic
= NULL
;
780 cfqd
->dispatch_slice
= 0;
783 static inline void cfq_slice_expired(struct cfq_data
*cfqd
, int preempted
)
785 struct cfq_queue
*cfqq
= cfqd
->active_queue
;
788 __cfq_slice_expired(cfqd
, cfqq
, preempted
);
801 static int cfq_get_next_prio_level(struct cfq_data
*cfqd
)
810 for (p
= cfqd
->cur_prio
; p
<= cfqd
->cur_end_prio
; p
++) {
811 if (!list_empty(&cfqd
->rr_list
[p
])) {
820 if (++cfqd
->cur_end_prio
== CFQ_PRIO_LISTS
) {
821 cfqd
->cur_end_prio
= 0;
828 if (unlikely(prio
== -1))
831 BUG_ON(prio
>= CFQ_PRIO_LISTS
);
833 list_splice_init(&cfqd
->rr_list
[prio
], &cfqd
->cur_rr
);
835 cfqd
->cur_prio
= prio
+ 1;
836 if (cfqd
->cur_prio
> cfqd
->cur_end_prio
) {
837 cfqd
->cur_end_prio
= cfqd
->cur_prio
;
840 if (cfqd
->cur_end_prio
== CFQ_PRIO_LISTS
) {
842 cfqd
->cur_end_prio
= 0;
848 static struct cfq_queue
*cfq_set_active_queue(struct cfq_data
*cfqd
)
850 struct cfq_queue
*cfqq
= NULL
;
853 * if current list is non-empty, grab first entry. if it is empty,
854 * get next prio level and grab first entry then if any are spliced
856 if (!list_empty(&cfqd
->cur_rr
) || cfq_get_next_prio_level(cfqd
) != -1)
857 cfqq
= list_entry_cfqq(cfqd
->cur_rr
.next
);
860 * if we have idle queues and no rt or be queues had pending
861 * requests, either allow immediate service if the grace period
862 * has passed or arm the idle grace timer
864 if (!cfqq
&& !list_empty(&cfqd
->idle_rr
)) {
865 unsigned long end
= cfqd
->last_end_request
+ CFQ_IDLE_GRACE
;
867 if (time_after_eq(jiffies
, end
))
868 cfqq
= list_entry_cfqq(cfqd
->idle_rr
.next
);
870 mod_timer(&cfqd
->idle_class_timer
, end
);
873 __cfq_set_active_queue(cfqd
, cfqq
);
877 static int cfq_arm_slice_timer(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
882 WARN_ON(!RB_EMPTY(&cfqq
->sort_list
));
883 WARN_ON(cfqq
!= cfqd
->active_queue
);
886 * idle is disabled, either manually or by past process history
888 if (!cfqd
->cfq_slice_idle
)
890 if (!cfq_cfqq_idle_window(cfqq
))
893 * task has exited, don't wait
895 if (cfqd
->active_cic
&& !cfqd
->active_cic
->ioc
->task
)
898 cfq_mark_cfqq_must_dispatch(cfqq
);
899 cfq_mark_cfqq_wait_request(cfqq
);
901 sl
= min(cfqq
->slice_end
- 1, (unsigned long) cfqd
->cfq_slice_idle
);
902 mod_timer(&cfqd
->idle_slice_timer
, jiffies
+ sl
);
906 static void cfq_dispatch_insert(request_queue_t
*q
, struct cfq_rq
*crq
)
908 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
909 struct cfq_queue
*cfqq
= crq
->cfq_queue
;
911 cfqq
->next_crq
= cfq_find_next_crq(cfqd
, cfqq
, crq
);
912 cfq_remove_request(crq
->request
);
913 cfqq
->on_dispatch
[cfq_crq_is_sync(crq
)]++;
914 elv_dispatch_sort(q
, crq
->request
);
918 * return expired entry, or NULL to just start from scratch in rbtree
920 static inline struct cfq_rq
*cfq_check_fifo(struct cfq_queue
*cfqq
)
922 struct cfq_data
*cfqd
= cfqq
->cfqd
;
926 if (cfq_cfqq_fifo_expire(cfqq
))
929 if (!list_empty(&cfqq
->fifo
)) {
930 int fifo
= cfq_cfqq_class_sync(cfqq
);
932 crq
= RQ_DATA(list_entry_fifo(cfqq
->fifo
.next
));
934 if (time_after(jiffies
, rq
->start_time
+ cfqd
->cfq_fifo_expire
[fifo
])) {
935 cfq_mark_cfqq_fifo_expire(cfqq
);
944 * Scale schedule slice based on io priority. Use the sync time slice only
945 * if a queue is marked sync and has sync io queued. A sync queue with async
946 * io only, should not get full sync slice length.
949 cfq_prio_to_slice(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
951 const int base_slice
= cfqd
->cfq_slice
[cfq_cfqq_sync(cfqq
)];
953 WARN_ON(cfqq
->ioprio
>= IOPRIO_BE_NR
);
955 return base_slice
+ (base_slice
/CFQ_SLICE_SCALE
* (4 - cfqq
->ioprio
));
959 cfq_set_prio_slice(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
961 cfqq
->slice_end
= cfq_prio_to_slice(cfqd
, cfqq
) + jiffies
;
965 cfq_prio_to_maxrq(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
967 const int base_rq
= cfqd
->cfq_slice_async_rq
;
969 WARN_ON(cfqq
->ioprio
>= IOPRIO_BE_NR
);
971 return 2 * (base_rq
+ base_rq
* (CFQ_PRIO_LISTS
- 1 - cfqq
->ioprio
));
975 * get next queue for service
977 static struct cfq_queue
*cfq_select_queue(struct cfq_data
*cfqd
)
979 unsigned long now
= jiffies
;
980 struct cfq_queue
*cfqq
;
982 cfqq
= cfqd
->active_queue
;
989 if (!cfq_cfqq_must_dispatch(cfqq
) && time_after(now
, cfqq
->slice_end
))
993 * if queue has requests, dispatch one. if not, check if
994 * enough slice is left to wait for one
996 if (!RB_EMPTY(&cfqq
->sort_list
))
998 else if (cfq_cfqq_class_sync(cfqq
) &&
999 time_before(now
, cfqq
->slice_end
)) {
1000 if (cfq_arm_slice_timer(cfqd
, cfqq
))
1005 cfq_slice_expired(cfqd
, 0);
1007 cfqq
= cfq_set_active_queue(cfqd
);
1013 __cfq_dispatch_requests(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
1018 BUG_ON(RB_EMPTY(&cfqq
->sort_list
));
1024 * follow expired path, else get first next available
1026 if ((crq
= cfq_check_fifo(cfqq
)) == NULL
)
1027 crq
= cfqq
->next_crq
;
1030 * finally, insert request into driver dispatch list
1032 cfq_dispatch_insert(cfqd
->queue
, crq
);
1034 cfqd
->dispatch_slice
++;
1037 if (!cfqd
->active_cic
) {
1038 atomic_inc(&crq
->io_context
->ioc
->refcount
);
1039 cfqd
->active_cic
= crq
->io_context
;
1042 if (RB_EMPTY(&cfqq
->sort_list
))
1045 } while (dispatched
< max_dispatch
);
1048 * if slice end isn't set yet, set it. if at least one request was
1049 * sync, use the sync time slice value
1051 if (!cfqq
->slice_end
)
1052 cfq_set_prio_slice(cfqd
, cfqq
);
1055 * expire an async queue immediately if it has used up its slice. idle
1056 * queue always expire after 1 dispatch round.
1058 if ((!cfq_cfqq_sync(cfqq
) &&
1059 cfqd
->dispatch_slice
>= cfq_prio_to_maxrq(cfqd
, cfqq
)) ||
1060 cfq_class_idle(cfqq
))
1061 cfq_slice_expired(cfqd
, 0);
1067 cfq_forced_dispatch_cfqqs(struct list_head
*list
)
1070 struct cfq_queue
*cfqq
, *next
;
1073 list_for_each_entry_safe(cfqq
, next
, list
, cfq_list
) {
1074 while ((crq
= cfqq
->next_crq
)) {
1075 cfq_dispatch_insert(cfqq
->cfqd
->queue
, crq
);
1078 BUG_ON(!list_empty(&cfqq
->fifo
));
1084 cfq_forced_dispatch(struct cfq_data
*cfqd
)
1086 int i
, dispatched
= 0;
1088 for (i
= 0; i
< CFQ_PRIO_LISTS
; i
++)
1089 dispatched
+= cfq_forced_dispatch_cfqqs(&cfqd
->rr_list
[i
]);
1091 dispatched
+= cfq_forced_dispatch_cfqqs(&cfqd
->busy_rr
);
1092 dispatched
+= cfq_forced_dispatch_cfqqs(&cfqd
->cur_rr
);
1093 dispatched
+= cfq_forced_dispatch_cfqqs(&cfqd
->idle_rr
);
1095 cfq_slice_expired(cfqd
, 0);
1097 BUG_ON(cfqd
->busy_queues
);
1103 cfq_dispatch_requests(request_queue_t
*q
, int force
)
1105 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
1106 struct cfq_queue
*cfqq
;
1108 if (!cfqd
->busy_queues
)
1111 if (unlikely(force
))
1112 return cfq_forced_dispatch(cfqd
);
1114 cfqq
= cfq_select_queue(cfqd
);
1119 * if idle window is disabled, allow queue buildup
1121 if (!cfq_cfqq_idle_window(cfqq
) &&
1122 cfqd
->rq_in_driver
>= cfqd
->cfq_max_depth
)
1125 cfq_clear_cfqq_must_dispatch(cfqq
);
1126 cfq_clear_cfqq_wait_request(cfqq
);
1127 del_timer(&cfqd
->idle_slice_timer
);
1129 max_dispatch
= cfqd
->cfq_quantum
;
1130 if (cfq_class_idle(cfqq
))
1133 return __cfq_dispatch_requests(cfqd
, cfqq
, max_dispatch
);
1140 * task holds one reference to the queue, dropped when task exits. each crq
1141 * in-flight on this queue also holds a reference, dropped when crq is freed.
1143 * queue lock must be held here.
1145 static void cfq_put_queue(struct cfq_queue
*cfqq
)
1147 struct cfq_data
*cfqd
= cfqq
->cfqd
;
1149 BUG_ON(atomic_read(&cfqq
->ref
) <= 0);
1151 if (!atomic_dec_and_test(&cfqq
->ref
))
1154 BUG_ON(rb_first(&cfqq
->sort_list
));
1155 BUG_ON(cfqq
->allocated
[READ
] + cfqq
->allocated
[WRITE
]);
1156 BUG_ON(cfq_cfqq_on_rr(cfqq
));
1158 if (unlikely(cfqd
->active_queue
== cfqq
))
1159 __cfq_slice_expired(cfqd
, cfqq
, 0);
1162 * it's on the empty list and still hashed
1164 list_del(&cfqq
->cfq_list
);
1165 hlist_del(&cfqq
->cfq_hash
);
1166 kmem_cache_free(cfq_pool
, cfqq
);
1169 static inline struct cfq_queue
*
1170 __cfq_find_cfq_hash(struct cfq_data
*cfqd
, unsigned int key
, unsigned int prio
,
1173 struct hlist_head
*hash_list
= &cfqd
->cfq_hash
[hashval
];
1174 struct hlist_node
*entry
, *next
;
1176 hlist_for_each_safe(entry
, next
, hash_list
) {
1177 struct cfq_queue
*__cfqq
= list_entry_qhash(entry
);
1178 const unsigned short __p
= IOPRIO_PRIO_VALUE(__cfqq
->org_ioprio_class
, __cfqq
->org_ioprio
);
1180 if (__cfqq
->key
== key
&& (__p
== prio
|| prio
== CFQ_KEY_ANY
))
1187 static struct cfq_queue
*
1188 cfq_find_cfq_hash(struct cfq_data
*cfqd
, unsigned int key
, unsigned short prio
)
1190 return __cfq_find_cfq_hash(cfqd
, key
, prio
, hash_long(key
, CFQ_QHASH_SHIFT
));
1193 static void cfq_free_io_context(struct io_context
*ioc
)
1195 struct cfq_io_context
*__cic
;
1199 while ((n
= rb_first(&ioc
->cic_root
)) != NULL
) {
1200 __cic
= rb_entry(n
, struct cfq_io_context
, rb_node
);
1201 rb_erase(&__cic
->rb_node
, &ioc
->cic_root
);
1202 kmem_cache_free(cfq_ioc_pool
, __cic
);
1206 if (atomic_sub_and_test(freed
, &ioc_count
) && ioc_gone
)
1210 static void cfq_trim(struct io_context
*ioc
)
1212 ioc
->set_ioprio
= NULL
;
1213 cfq_free_io_context(ioc
);
1217 * Called with interrupts disabled
1219 static void cfq_exit_single_io_context(struct cfq_io_context
*cic
)
1221 struct cfq_data
*cfqd
= cic
->key
;
1229 WARN_ON(!irqs_disabled());
1231 spin_lock(q
->queue_lock
);
1233 if (cic
->cfqq
[ASYNC
]) {
1234 if (unlikely(cic
->cfqq
[ASYNC
] == cfqd
->active_queue
))
1235 __cfq_slice_expired(cfqd
, cic
->cfqq
[ASYNC
], 0);
1236 cfq_put_queue(cic
->cfqq
[ASYNC
]);
1237 cic
->cfqq
[ASYNC
] = NULL
;
1240 if (cic
->cfqq
[SYNC
]) {
1241 if (unlikely(cic
->cfqq
[SYNC
] == cfqd
->active_queue
))
1242 __cfq_slice_expired(cfqd
, cic
->cfqq
[SYNC
], 0);
1243 cfq_put_queue(cic
->cfqq
[SYNC
]);
1244 cic
->cfqq
[SYNC
] = NULL
;
1248 list_del_init(&cic
->queue_list
);
1249 spin_unlock(q
->queue_lock
);
1252 static void cfq_exit_io_context(struct io_context
*ioc
)
1254 struct cfq_io_context
*__cic
;
1255 unsigned long flags
;
1259 * put the reference this task is holding to the various queues
1261 read_lock_irqsave(&cfq_exit_lock
, flags
);
1263 n
= rb_first(&ioc
->cic_root
);
1265 __cic
= rb_entry(n
, struct cfq_io_context
, rb_node
);
1267 cfq_exit_single_io_context(__cic
);
1271 read_unlock_irqrestore(&cfq_exit_lock
, flags
);
1274 static struct cfq_io_context
*
1275 cfq_alloc_io_context(struct cfq_data
*cfqd
, gfp_t gfp_mask
)
1277 struct cfq_io_context
*cic
= kmem_cache_alloc(cfq_ioc_pool
, gfp_mask
);
1280 RB_CLEAR(&cic
->rb_node
);
1282 cic
->cfqq
[ASYNC
] = NULL
;
1283 cic
->cfqq
[SYNC
] = NULL
;
1284 cic
->last_end_request
= jiffies
;
1285 cic
->ttime_total
= 0;
1286 cic
->ttime_samples
= 0;
1287 cic
->ttime_mean
= 0;
1288 cic
->dtor
= cfq_free_io_context
;
1289 cic
->exit
= cfq_exit_io_context
;
1290 INIT_LIST_HEAD(&cic
->queue_list
);
1291 atomic_inc(&ioc_count
);
1297 static void cfq_init_prio_data(struct cfq_queue
*cfqq
)
1299 struct task_struct
*tsk
= current
;
1302 if (!cfq_cfqq_prio_changed(cfqq
))
1305 ioprio_class
= IOPRIO_PRIO_CLASS(tsk
->ioprio
);
1306 switch (ioprio_class
) {
1308 printk(KERN_ERR
"cfq: bad prio %x\n", ioprio_class
);
1309 case IOPRIO_CLASS_NONE
:
1311 * no prio set, place us in the middle of the BE classes
1313 cfqq
->ioprio
= task_nice_ioprio(tsk
);
1314 cfqq
->ioprio_class
= IOPRIO_CLASS_BE
;
1316 case IOPRIO_CLASS_RT
:
1317 cfqq
->ioprio
= task_ioprio(tsk
);
1318 cfqq
->ioprio_class
= IOPRIO_CLASS_RT
;
1320 case IOPRIO_CLASS_BE
:
1321 cfqq
->ioprio
= task_ioprio(tsk
);
1322 cfqq
->ioprio_class
= IOPRIO_CLASS_BE
;
1324 case IOPRIO_CLASS_IDLE
:
1325 cfqq
->ioprio_class
= IOPRIO_CLASS_IDLE
;
1327 cfq_clear_cfqq_idle_window(cfqq
);
1332 * keep track of original prio settings in case we have to temporarily
1333 * elevate the priority of this queue
1335 cfqq
->org_ioprio
= cfqq
->ioprio
;
1336 cfqq
->org_ioprio_class
= cfqq
->ioprio_class
;
1338 if (cfq_cfqq_on_rr(cfqq
))
1339 cfq_resort_rr_list(cfqq
, 0);
1341 cfq_clear_cfqq_prio_changed(cfqq
);
1344 static inline void changed_ioprio(struct cfq_io_context
*cic
)
1346 struct cfq_data
*cfqd
= cic
->key
;
1347 struct cfq_queue
*cfqq
;
1349 spin_lock(cfqd
->queue
->queue_lock
);
1350 cfqq
= cic
->cfqq
[ASYNC
];
1352 struct cfq_queue
*new_cfqq
;
1353 new_cfqq
= cfq_get_queue(cfqd
, CFQ_KEY_ASYNC
,
1354 cic
->ioc
->task
, GFP_ATOMIC
);
1356 cic
->cfqq
[ASYNC
] = new_cfqq
;
1357 cfq_put_queue(cfqq
);
1360 cfqq
= cic
->cfqq
[SYNC
];
1362 cfq_mark_cfqq_prio_changed(cfqq
);
1363 cfq_init_prio_data(cfqq
);
1365 spin_unlock(cfqd
->queue
->queue_lock
);
1370 * callback from sys_ioprio_set, irqs are disabled
1372 static int cfq_ioc_set_ioprio(struct io_context
*ioc
, unsigned int ioprio
)
1374 struct cfq_io_context
*cic
;
1377 write_lock(&cfq_exit_lock
);
1379 n
= rb_first(&ioc
->cic_root
);
1381 cic
= rb_entry(n
, struct cfq_io_context
, rb_node
);
1383 changed_ioprio(cic
);
1387 write_unlock(&cfq_exit_lock
);
1392 static struct cfq_queue
*
1393 cfq_get_queue(struct cfq_data
*cfqd
, unsigned int key
, struct task_struct
*tsk
,
1396 const int hashval
= hash_long(key
, CFQ_QHASH_SHIFT
);
1397 struct cfq_queue
*cfqq
, *new_cfqq
= NULL
;
1398 unsigned short ioprio
;
1401 ioprio
= tsk
->ioprio
;
1402 cfqq
= __cfq_find_cfq_hash(cfqd
, key
, ioprio
, hashval
);
1408 } else if (gfp_mask
& __GFP_WAIT
) {
1409 spin_unlock_irq(cfqd
->queue
->queue_lock
);
1410 new_cfqq
= kmem_cache_alloc(cfq_pool
, gfp_mask
);
1411 spin_lock_irq(cfqd
->queue
->queue_lock
);
1414 cfqq
= kmem_cache_alloc(cfq_pool
, gfp_mask
);
1419 memset(cfqq
, 0, sizeof(*cfqq
));
1421 INIT_HLIST_NODE(&cfqq
->cfq_hash
);
1422 INIT_LIST_HEAD(&cfqq
->cfq_list
);
1423 RB_CLEAR_ROOT(&cfqq
->sort_list
);
1424 INIT_LIST_HEAD(&cfqq
->fifo
);
1427 hlist_add_head(&cfqq
->cfq_hash
, &cfqd
->cfq_hash
[hashval
]);
1428 atomic_set(&cfqq
->ref
, 0);
1430 cfqq
->service_last
= 0;
1432 * set ->slice_left to allow preemption for a new process
1434 cfqq
->slice_left
= 2 * cfqd
->cfq_slice_idle
;
1435 cfq_mark_cfqq_idle_window(cfqq
);
1436 cfq_mark_cfqq_prio_changed(cfqq
);
1437 cfq_init_prio_data(cfqq
);
1441 kmem_cache_free(cfq_pool
, new_cfqq
);
1443 atomic_inc(&cfqq
->ref
);
1445 WARN_ON((gfp_mask
& __GFP_WAIT
) && !cfqq
);
1449 static struct cfq_io_context
*
1450 cfq_cic_rb_lookup(struct cfq_data
*cfqd
, struct io_context
*ioc
)
1452 struct rb_node
*n
= ioc
->cic_root
.rb_node
;
1453 struct cfq_io_context
*cic
;
1457 cic
= rb_entry(n
, struct cfq_io_context
, rb_node
);
1461 else if (key
> cic
->key
)
1471 cfq_cic_link(struct cfq_data
*cfqd
, struct io_context
*ioc
,
1472 struct cfq_io_context
*cic
)
1474 struct rb_node
**p
= &ioc
->cic_root
.rb_node
;
1475 struct rb_node
*parent
= NULL
;
1476 struct cfq_io_context
*__cic
;
1478 read_lock(&cfq_exit_lock
);
1483 ioc
->set_ioprio
= cfq_ioc_set_ioprio
;
1487 __cic
= rb_entry(parent
, struct cfq_io_context
, rb_node
);
1489 if (cic
->key
< __cic
->key
)
1491 else if (cic
->key
> __cic
->key
)
1492 p
= &(*p
)->rb_right
;
1497 rb_link_node(&cic
->rb_node
, parent
, p
);
1498 rb_insert_color(&cic
->rb_node
, &ioc
->cic_root
);
1499 list_add(&cic
->queue_list
, &cfqd
->cic_list
);
1500 read_unlock(&cfq_exit_lock
);
1504 * Setup general io context and cfq io context. There can be several cfq
1505 * io contexts per general io context, if this process is doing io to more
1506 * than one device managed by cfq.
1508 static struct cfq_io_context
*
1509 cfq_get_io_context(struct cfq_data
*cfqd
, gfp_t gfp_mask
)
1511 struct io_context
*ioc
= NULL
;
1512 struct cfq_io_context
*cic
;
1514 might_sleep_if(gfp_mask
& __GFP_WAIT
);
1516 ioc
= get_io_context(gfp_mask
);
1520 cic
= cfq_cic_rb_lookup(cfqd
, ioc
);
1524 cic
= cfq_alloc_io_context(cfqd
, gfp_mask
);
1528 cfq_cic_link(cfqd
, ioc
, cic
);
1532 put_io_context(ioc
);
1537 cfq_update_io_thinktime(struct cfq_data
*cfqd
, struct cfq_io_context
*cic
)
1539 unsigned long elapsed
, ttime
;
1542 * if this context already has stuff queued, thinktime is from
1543 * last queue not last end
1546 if (time_after(cic
->last_end_request
, cic
->last_queue
))
1547 elapsed
= jiffies
- cic
->last_end_request
;
1549 elapsed
= jiffies
- cic
->last_queue
;
1551 elapsed
= jiffies
- cic
->last_end_request
;
1554 ttime
= min(elapsed
, 2UL * cfqd
->cfq_slice_idle
);
1556 cic
->ttime_samples
= (7*cic
->ttime_samples
+ 256) / 8;
1557 cic
->ttime_total
= (7*cic
->ttime_total
+ 256*ttime
) / 8;
1558 cic
->ttime_mean
= (cic
->ttime_total
+ 128) / cic
->ttime_samples
;
1561 #define sample_valid(samples) ((samples) > 80)
1564 * Disable idle window if the process thinks too long or seeks so much that
1568 cfq_update_idle_window(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
1569 struct cfq_io_context
*cic
)
1571 int enable_idle
= cfq_cfqq_idle_window(cfqq
);
1573 if (!cic
->ioc
->task
|| !cfqd
->cfq_slice_idle
)
1575 else if (sample_valid(cic
->ttime_samples
)) {
1576 if (cic
->ttime_mean
> cfqd
->cfq_slice_idle
)
1583 cfq_mark_cfqq_idle_window(cfqq
);
1585 cfq_clear_cfqq_idle_window(cfqq
);
1590 * Check if new_cfqq should preempt the currently active queue. Return 0 for
1591 * no or if we aren't sure, a 1 will cause a preempt.
1594 cfq_should_preempt(struct cfq_data
*cfqd
, struct cfq_queue
*new_cfqq
,
1597 struct cfq_queue
*cfqq
= cfqd
->active_queue
;
1599 if (cfq_class_idle(new_cfqq
))
1605 if (cfq_class_idle(cfqq
))
1607 if (!cfq_cfqq_wait_request(new_cfqq
))
1610 * if it doesn't have slice left, forget it
1612 if (new_cfqq
->slice_left
< cfqd
->cfq_slice_idle
)
1614 if (cfq_crq_is_sync(crq
) && !cfq_cfqq_sync(cfqq
))
1621 * cfqq preempts the active queue. if we allowed preempt with no slice left,
1622 * let it have half of its nominal slice.
1624 static void cfq_preempt_queue(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
1626 struct cfq_queue
*__cfqq
, *next
;
1628 list_for_each_entry_safe(__cfqq
, next
, &cfqd
->cur_rr
, cfq_list
)
1629 cfq_resort_rr_list(__cfqq
, 1);
1631 if (!cfqq
->slice_left
)
1632 cfqq
->slice_left
= cfq_prio_to_slice(cfqd
, cfqq
) / 2;
1634 cfqq
->slice_end
= cfqq
->slice_left
+ jiffies
;
1635 __cfq_slice_expired(cfqd
, cfqq
, 1);
1636 __cfq_set_active_queue(cfqd
, cfqq
);
1640 * should really be a ll_rw_blk.c helper
1642 static void cfq_start_queueing(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
1644 request_queue_t
*q
= cfqd
->queue
;
1646 if (!blk_queue_plugged(q
))
1649 __generic_unplug_device(q
);
1653 * Called when a new fs request (crq) is added (to cfqq). Check if there's
1654 * something we should do about it
1657 cfq_crq_enqueued(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
1660 struct cfq_io_context
*cic
;
1662 cfqq
->next_crq
= cfq_choose_req(cfqd
, cfqq
->next_crq
, crq
);
1665 * we never wait for an async request and we don't allow preemption
1666 * of an async request. so just return early
1668 if (!cfq_crq_is_sync(crq
))
1671 cic
= crq
->io_context
;
1673 cfq_update_io_thinktime(cfqd
, cic
);
1674 cfq_update_idle_window(cfqd
, cfqq
, cic
);
1676 cic
->last_queue
= jiffies
;
1678 if (cfqq
== cfqd
->active_queue
) {
1680 * if we are waiting for a request for this queue, let it rip
1681 * immediately and flag that we must not expire this queue
1684 if (cfq_cfqq_wait_request(cfqq
)) {
1685 cfq_mark_cfqq_must_dispatch(cfqq
);
1686 del_timer(&cfqd
->idle_slice_timer
);
1687 cfq_start_queueing(cfqd
, cfqq
);
1689 } else if (cfq_should_preempt(cfqd
, cfqq
, crq
)) {
1691 * not the active queue - expire current slice if it is
1692 * idle and has expired it's mean thinktime or this new queue
1693 * has some old slice time left and is of higher priority
1695 cfq_preempt_queue(cfqd
, cfqq
);
1696 cfq_mark_cfqq_must_dispatch(cfqq
);
1697 cfq_start_queueing(cfqd
, cfqq
);
1701 static void cfq_insert_request(request_queue_t
*q
, struct request
*rq
)
1703 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
1704 struct cfq_rq
*crq
= RQ_DATA(rq
);
1705 struct cfq_queue
*cfqq
= crq
->cfq_queue
;
1707 cfq_init_prio_data(cfqq
);
1709 cfq_add_crq_rb(crq
);
1711 list_add_tail(&rq
->queuelist
, &cfqq
->fifo
);
1713 if (rq_mergeable(rq
))
1714 cfq_add_crq_hash(cfqd
, crq
);
1716 cfq_crq_enqueued(cfqd
, cfqq
, crq
);
1719 static void cfq_completed_request(request_queue_t
*q
, struct request
*rq
)
1721 struct cfq_rq
*crq
= RQ_DATA(rq
);
1722 struct cfq_queue
*cfqq
= crq
->cfq_queue
;
1723 struct cfq_data
*cfqd
= cfqq
->cfqd
;
1724 const int sync
= cfq_crq_is_sync(crq
);
1729 WARN_ON(!cfqd
->rq_in_driver
);
1730 WARN_ON(!cfqq
->on_dispatch
[sync
]);
1731 cfqd
->rq_in_driver
--;
1732 cfqq
->on_dispatch
[sync
]--;
1734 if (!cfq_class_idle(cfqq
))
1735 cfqd
->last_end_request
= now
;
1737 if (!cfq_cfqq_dispatched(cfqq
)) {
1738 if (cfq_cfqq_on_rr(cfqq
)) {
1739 cfqq
->service_last
= now
;
1740 cfq_resort_rr_list(cfqq
, 0);
1742 cfq_schedule_dispatch(cfqd
);
1745 if (cfq_crq_is_sync(crq
))
1746 crq
->io_context
->last_end_request
= now
;
1749 static struct request
*
1750 cfq_former_request(request_queue_t
*q
, struct request
*rq
)
1752 struct cfq_rq
*crq
= RQ_DATA(rq
);
1753 struct rb_node
*rbprev
= rb_prev(&crq
->rb_node
);
1756 return rb_entry_crq(rbprev
)->request
;
1761 static struct request
*
1762 cfq_latter_request(request_queue_t
*q
, struct request
*rq
)
1764 struct cfq_rq
*crq
= RQ_DATA(rq
);
1765 struct rb_node
*rbnext
= rb_next(&crq
->rb_node
);
1768 return rb_entry_crq(rbnext
)->request
;
1774 * we temporarily boost lower priority queues if they are holding fs exclusive
1775 * resources. they are boosted to normal prio (CLASS_BE/4)
1777 static void cfq_prio_boost(struct cfq_queue
*cfqq
)
1779 const int ioprio_class
= cfqq
->ioprio_class
;
1780 const int ioprio
= cfqq
->ioprio
;
1782 if (has_fs_excl()) {
1784 * boost idle prio on transactions that would lock out other
1785 * users of the filesystem
1787 if (cfq_class_idle(cfqq
))
1788 cfqq
->ioprio_class
= IOPRIO_CLASS_BE
;
1789 if (cfqq
->ioprio
> IOPRIO_NORM
)
1790 cfqq
->ioprio
= IOPRIO_NORM
;
1793 * check if we need to unboost the queue
1795 if (cfqq
->ioprio_class
!= cfqq
->org_ioprio_class
)
1796 cfqq
->ioprio_class
= cfqq
->org_ioprio_class
;
1797 if (cfqq
->ioprio
!= cfqq
->org_ioprio
)
1798 cfqq
->ioprio
= cfqq
->org_ioprio
;
1802 * refile between round-robin lists if we moved the priority class
1804 if ((ioprio_class
!= cfqq
->ioprio_class
|| ioprio
!= cfqq
->ioprio
) &&
1805 cfq_cfqq_on_rr(cfqq
))
1806 cfq_resort_rr_list(cfqq
, 0);
1809 static inline pid_t
cfq_queue_pid(struct task_struct
*task
, int rw
)
1811 if (rw
== READ
|| process_sync(task
))
1814 return CFQ_KEY_ASYNC
;
1818 __cfq_may_queue(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
1819 struct task_struct
*task
, int rw
)
1822 if ((cfq_cfqq_wait_request(cfqq
) || cfq_cfqq_must_alloc(cfqq
)) &&
1823 !cfq_cfqq_must_alloc_slice(cfqq
)) {
1824 cfq_mark_cfqq_must_alloc_slice(cfqq
);
1825 return ELV_MQUEUE_MUST
;
1828 return ELV_MQUEUE_MAY
;
1830 if (!cfqq
|| task
->flags
& PF_MEMALLOC
)
1831 return ELV_MQUEUE_MAY
;
1832 if (!cfqq
->allocated
[rw
] || cfq_cfqq_must_alloc(cfqq
)) {
1833 if (cfq_cfqq_wait_request(cfqq
))
1834 return ELV_MQUEUE_MUST
;
1837 * only allow 1 ELV_MQUEUE_MUST per slice, otherwise we
1838 * can quickly flood the queue with writes from a single task
1840 if (rw
== READ
|| !cfq_cfqq_must_alloc_slice(cfqq
)) {
1841 cfq_mark_cfqq_must_alloc_slice(cfqq
);
1842 return ELV_MQUEUE_MUST
;
1845 return ELV_MQUEUE_MAY
;
1847 if (cfq_class_idle(cfqq
))
1848 return ELV_MQUEUE_NO
;
1849 if (cfqq
->allocated
[rw
] >= cfqd
->max_queued
) {
1850 struct io_context
*ioc
= get_io_context(GFP_ATOMIC
);
1851 int ret
= ELV_MQUEUE_NO
;
1853 if (ioc
&& ioc
->nr_batch_requests
)
1854 ret
= ELV_MQUEUE_MAY
;
1856 put_io_context(ioc
);
1860 return ELV_MQUEUE_MAY
;
1864 static int cfq_may_queue(request_queue_t
*q
, int rw
, struct bio
*bio
)
1866 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
1867 struct task_struct
*tsk
= current
;
1868 struct cfq_queue
*cfqq
;
1871 * don't force setup of a queue from here, as a call to may_queue
1872 * does not necessarily imply that a request actually will be queued.
1873 * so just lookup a possibly existing queue, or return 'may queue'
1876 cfqq
= cfq_find_cfq_hash(cfqd
, cfq_queue_pid(tsk
, rw
), tsk
->ioprio
);
1878 cfq_init_prio_data(cfqq
);
1879 cfq_prio_boost(cfqq
);
1881 return __cfq_may_queue(cfqd
, cfqq
, tsk
, rw
);
1884 return ELV_MQUEUE_MAY
;
1887 static void cfq_check_waiters(request_queue_t
*q
, struct cfq_queue
*cfqq
)
1889 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
1890 struct request_list
*rl
= &q
->rq
;
1892 if (cfqq
->allocated
[READ
] <= cfqd
->max_queued
|| cfqd
->rq_starved
) {
1894 if (waitqueue_active(&rl
->wait
[READ
]))
1895 wake_up(&rl
->wait
[READ
]);
1898 if (cfqq
->allocated
[WRITE
] <= cfqd
->max_queued
|| cfqd
->rq_starved
) {
1900 if (waitqueue_active(&rl
->wait
[WRITE
]))
1901 wake_up(&rl
->wait
[WRITE
]);
1906 * queue lock held here
1908 static void cfq_put_request(request_queue_t
*q
, struct request
*rq
)
1910 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
1911 struct cfq_rq
*crq
= RQ_DATA(rq
);
1914 struct cfq_queue
*cfqq
= crq
->cfq_queue
;
1915 const int rw
= rq_data_dir(rq
);
1917 BUG_ON(!cfqq
->allocated
[rw
]);
1918 cfqq
->allocated
[rw
]--;
1920 put_io_context(crq
->io_context
->ioc
);
1922 mempool_free(crq
, cfqd
->crq_pool
);
1923 rq
->elevator_private
= NULL
;
1925 cfq_check_waiters(q
, cfqq
);
1926 cfq_put_queue(cfqq
);
1931 * Allocate cfq data structures associated with this request.
1934 cfq_set_request(request_queue_t
*q
, struct request
*rq
, struct bio
*bio
,
1937 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
1938 struct task_struct
*tsk
= current
;
1939 struct cfq_io_context
*cic
;
1940 const int rw
= rq_data_dir(rq
);
1941 pid_t key
= cfq_queue_pid(tsk
, rw
);
1942 struct cfq_queue
*cfqq
;
1944 unsigned long flags
;
1945 int is_sync
= key
!= CFQ_KEY_ASYNC
;
1947 might_sleep_if(gfp_mask
& __GFP_WAIT
);
1949 cic
= cfq_get_io_context(cfqd
, gfp_mask
);
1951 spin_lock_irqsave(q
->queue_lock
, flags
);
1956 if (!cic
->cfqq
[is_sync
]) {
1957 cfqq
= cfq_get_queue(cfqd
, key
, tsk
, gfp_mask
);
1961 cic
->cfqq
[is_sync
] = cfqq
;
1963 cfqq
= cic
->cfqq
[is_sync
];
1965 cfqq
->allocated
[rw
]++;
1966 cfq_clear_cfqq_must_alloc(cfqq
);
1967 cfqd
->rq_starved
= 0;
1968 atomic_inc(&cfqq
->ref
);
1969 spin_unlock_irqrestore(q
->queue_lock
, flags
);
1971 crq
= mempool_alloc(cfqd
->crq_pool
, gfp_mask
);
1973 RB_CLEAR(&crq
->rb_node
);
1976 INIT_HLIST_NODE(&crq
->hash
);
1977 crq
->cfq_queue
= cfqq
;
1978 crq
->io_context
= cic
;
1981 cfq_mark_crq_is_sync(crq
);
1983 cfq_clear_crq_is_sync(crq
);
1985 rq
->elevator_private
= crq
;
1989 spin_lock_irqsave(q
->queue_lock
, flags
);
1990 cfqq
->allocated
[rw
]--;
1991 if (!(cfqq
->allocated
[0] + cfqq
->allocated
[1]))
1992 cfq_mark_cfqq_must_alloc(cfqq
);
1993 cfq_put_queue(cfqq
);
1996 put_io_context(cic
->ioc
);
1998 * mark us rq allocation starved. we need to kickstart the process
1999 * ourselves if there are no pending requests that can do it for us.
2000 * that would be an extremely rare OOM situation
2002 cfqd
->rq_starved
= 1;
2003 cfq_schedule_dispatch(cfqd
);
2004 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2008 static void cfq_kick_queue(void *data
)
2010 request_queue_t
*q
= data
;
2011 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
2012 unsigned long flags
;
2014 spin_lock_irqsave(q
->queue_lock
, flags
);
2016 if (cfqd
->rq_starved
) {
2017 struct request_list
*rl
= &q
->rq
;
2020 * we aren't guaranteed to get a request after this, but we
2021 * have to be opportunistic
2024 if (waitqueue_active(&rl
->wait
[READ
]))
2025 wake_up(&rl
->wait
[READ
]);
2026 if (waitqueue_active(&rl
->wait
[WRITE
]))
2027 wake_up(&rl
->wait
[WRITE
]);
2032 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2036 * Timer running if the active_queue is currently idling inside its time slice
2038 static void cfq_idle_slice_timer(unsigned long data
)
2040 struct cfq_data
*cfqd
= (struct cfq_data
*) data
;
2041 struct cfq_queue
*cfqq
;
2042 unsigned long flags
;
2044 spin_lock_irqsave(cfqd
->queue
->queue_lock
, flags
);
2046 if ((cfqq
= cfqd
->active_queue
) != NULL
) {
2047 unsigned long now
= jiffies
;
2052 if (time_after(now
, cfqq
->slice_end
))
2056 * only expire and reinvoke request handler, if there are
2057 * other queues with pending requests
2059 if (!cfqd
->busy_queues
) {
2060 cfqd
->idle_slice_timer
.expires
= min(now
+ cfqd
->cfq_slice_idle
, cfqq
->slice_end
);
2061 add_timer(&cfqd
->idle_slice_timer
);
2066 * not expired and it has a request pending, let it dispatch
2068 if (!RB_EMPTY(&cfqq
->sort_list
)) {
2069 cfq_mark_cfqq_must_dispatch(cfqq
);
2074 cfq_slice_expired(cfqd
, 0);
2076 cfq_schedule_dispatch(cfqd
);
2078 spin_unlock_irqrestore(cfqd
->queue
->queue_lock
, flags
);
2082 * Timer running if an idle class queue is waiting for service
2084 static void cfq_idle_class_timer(unsigned long data
)
2086 struct cfq_data
*cfqd
= (struct cfq_data
*) data
;
2087 unsigned long flags
, end
;
2089 spin_lock_irqsave(cfqd
->queue
->queue_lock
, flags
);
2092 * race with a non-idle queue, reset timer
2094 end
= cfqd
->last_end_request
+ CFQ_IDLE_GRACE
;
2095 if (!time_after_eq(jiffies
, end
)) {
2096 cfqd
->idle_class_timer
.expires
= end
;
2097 add_timer(&cfqd
->idle_class_timer
);
2099 cfq_schedule_dispatch(cfqd
);
2101 spin_unlock_irqrestore(cfqd
->queue
->queue_lock
, flags
);
2104 static void cfq_shutdown_timer_wq(struct cfq_data
*cfqd
)
2106 del_timer_sync(&cfqd
->idle_slice_timer
);
2107 del_timer_sync(&cfqd
->idle_class_timer
);
2108 blk_sync_queue(cfqd
->queue
);
2111 static void cfq_exit_queue(elevator_t
*e
)
2113 struct cfq_data
*cfqd
= e
->elevator_data
;
2114 request_queue_t
*q
= cfqd
->queue
;
2116 cfq_shutdown_timer_wq(cfqd
);
2118 write_lock(&cfq_exit_lock
);
2119 spin_lock_irq(q
->queue_lock
);
2121 if (cfqd
->active_queue
)
2122 __cfq_slice_expired(cfqd
, cfqd
->active_queue
, 0);
2124 while (!list_empty(&cfqd
->cic_list
)) {
2125 struct cfq_io_context
*cic
= list_entry(cfqd
->cic_list
.next
,
2126 struct cfq_io_context
,
2128 if (cic
->cfqq
[ASYNC
]) {
2129 cfq_put_queue(cic
->cfqq
[ASYNC
]);
2130 cic
->cfqq
[ASYNC
] = NULL
;
2132 if (cic
->cfqq
[SYNC
]) {
2133 cfq_put_queue(cic
->cfqq
[SYNC
]);
2134 cic
->cfqq
[SYNC
] = NULL
;
2137 list_del_init(&cic
->queue_list
);
2140 spin_unlock_irq(q
->queue_lock
);
2141 write_unlock(&cfq_exit_lock
);
2143 cfq_shutdown_timer_wq(cfqd
);
2145 mempool_destroy(cfqd
->crq_pool
);
2146 kfree(cfqd
->crq_hash
);
2147 kfree(cfqd
->cfq_hash
);
2151 static int cfq_init_queue(request_queue_t
*q
, elevator_t
*e
)
2153 struct cfq_data
*cfqd
;
2156 cfqd
= kmalloc(sizeof(*cfqd
), GFP_KERNEL
);
2160 memset(cfqd
, 0, sizeof(*cfqd
));
2162 for (i
= 0; i
< CFQ_PRIO_LISTS
; i
++)
2163 INIT_LIST_HEAD(&cfqd
->rr_list
[i
]);
2165 INIT_LIST_HEAD(&cfqd
->busy_rr
);
2166 INIT_LIST_HEAD(&cfqd
->cur_rr
);
2167 INIT_LIST_HEAD(&cfqd
->idle_rr
);
2168 INIT_LIST_HEAD(&cfqd
->empty_list
);
2169 INIT_LIST_HEAD(&cfqd
->cic_list
);
2171 cfqd
->crq_hash
= kmalloc(sizeof(struct hlist_head
) * CFQ_MHASH_ENTRIES
, GFP_KERNEL
);
2172 if (!cfqd
->crq_hash
)
2175 cfqd
->cfq_hash
= kmalloc(sizeof(struct hlist_head
) * CFQ_QHASH_ENTRIES
, GFP_KERNEL
);
2176 if (!cfqd
->cfq_hash
)
2179 cfqd
->crq_pool
= mempool_create_slab_pool(BLKDEV_MIN_RQ
, crq_pool
);
2180 if (!cfqd
->crq_pool
)
2183 for (i
= 0; i
< CFQ_MHASH_ENTRIES
; i
++)
2184 INIT_HLIST_HEAD(&cfqd
->crq_hash
[i
]);
2185 for (i
= 0; i
< CFQ_QHASH_ENTRIES
; i
++)
2186 INIT_HLIST_HEAD(&cfqd
->cfq_hash
[i
]);
2188 e
->elevator_data
= cfqd
;
2192 cfqd
->max_queued
= q
->nr_requests
/ 4;
2193 q
->nr_batching
= cfq_queued
;
2195 init_timer(&cfqd
->idle_slice_timer
);
2196 cfqd
->idle_slice_timer
.function
= cfq_idle_slice_timer
;
2197 cfqd
->idle_slice_timer
.data
= (unsigned long) cfqd
;
2199 init_timer(&cfqd
->idle_class_timer
);
2200 cfqd
->idle_class_timer
.function
= cfq_idle_class_timer
;
2201 cfqd
->idle_class_timer
.data
= (unsigned long) cfqd
;
2203 INIT_WORK(&cfqd
->unplug_work
, cfq_kick_queue
, q
);
2205 cfqd
->cfq_queued
= cfq_queued
;
2206 cfqd
->cfq_quantum
= cfq_quantum
;
2207 cfqd
->cfq_fifo_expire
[0] = cfq_fifo_expire
[0];
2208 cfqd
->cfq_fifo_expire
[1] = cfq_fifo_expire
[1];
2209 cfqd
->cfq_back_max
= cfq_back_max
;
2210 cfqd
->cfq_back_penalty
= cfq_back_penalty
;
2211 cfqd
->cfq_slice
[0] = cfq_slice_async
;
2212 cfqd
->cfq_slice
[1] = cfq_slice_sync
;
2213 cfqd
->cfq_slice_async_rq
= cfq_slice_async_rq
;
2214 cfqd
->cfq_slice_idle
= cfq_slice_idle
;
2215 cfqd
->cfq_max_depth
= cfq_max_depth
;
2219 kfree(cfqd
->cfq_hash
);
2221 kfree(cfqd
->crq_hash
);
2227 static void cfq_slab_kill(void)
2230 kmem_cache_destroy(crq_pool
);
2232 kmem_cache_destroy(cfq_pool
);
2234 kmem_cache_destroy(cfq_ioc_pool
);
2237 static int __init
cfq_slab_setup(void)
2239 crq_pool
= kmem_cache_create("crq_pool", sizeof(struct cfq_rq
), 0, 0,
2244 cfq_pool
= kmem_cache_create("cfq_pool", sizeof(struct cfq_queue
), 0, 0,
2249 cfq_ioc_pool
= kmem_cache_create("cfq_ioc_pool",
2250 sizeof(struct cfq_io_context
), 0, 0, NULL
, NULL
);
2261 * sysfs parts below -->
2265 cfq_var_show(unsigned int var
, char *page
)
2267 return sprintf(page
, "%d\n", var
);
2271 cfq_var_store(unsigned int *var
, const char *page
, size_t count
)
2273 char *p
= (char *) page
;
2275 *var
= simple_strtoul(p
, &p
, 10);
2279 #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \
2280 static ssize_t __FUNC(elevator_t *e, char *page) \
2282 struct cfq_data *cfqd = e->elevator_data; \
2283 unsigned int __data = __VAR; \
2285 __data = jiffies_to_msecs(__data); \
2286 return cfq_var_show(__data, (page)); \
2288 SHOW_FUNCTION(cfq_quantum_show
, cfqd
->cfq_quantum
, 0);
2289 SHOW_FUNCTION(cfq_queued_show
, cfqd
->cfq_queued
, 0);
2290 SHOW_FUNCTION(cfq_fifo_expire_sync_show
, cfqd
->cfq_fifo_expire
[1], 1);
2291 SHOW_FUNCTION(cfq_fifo_expire_async_show
, cfqd
->cfq_fifo_expire
[0], 1);
2292 SHOW_FUNCTION(cfq_back_seek_max_show
, cfqd
->cfq_back_max
, 0);
2293 SHOW_FUNCTION(cfq_back_seek_penalty_show
, cfqd
->cfq_back_penalty
, 0);
2294 SHOW_FUNCTION(cfq_slice_idle_show
, cfqd
->cfq_slice_idle
, 1);
2295 SHOW_FUNCTION(cfq_slice_sync_show
, cfqd
->cfq_slice
[1], 1);
2296 SHOW_FUNCTION(cfq_slice_async_show
, cfqd
->cfq_slice
[0], 1);
2297 SHOW_FUNCTION(cfq_slice_async_rq_show
, cfqd
->cfq_slice_async_rq
, 0);
2298 SHOW_FUNCTION(cfq_max_depth_show
, cfqd
->cfq_max_depth
, 0);
2299 #undef SHOW_FUNCTION
2301 #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \
2302 static ssize_t __FUNC(elevator_t *e, const char *page, size_t count) \
2304 struct cfq_data *cfqd = e->elevator_data; \
2305 unsigned int __data; \
2306 int ret = cfq_var_store(&__data, (page), count); \
2307 if (__data < (MIN)) \
2309 else if (__data > (MAX)) \
2312 *(__PTR) = msecs_to_jiffies(__data); \
2314 *(__PTR) = __data; \
2317 STORE_FUNCTION(cfq_quantum_store
, &cfqd
->cfq_quantum
, 1, UINT_MAX
, 0);
2318 STORE_FUNCTION(cfq_queued_store
, &cfqd
->cfq_queued
, 1, UINT_MAX
, 0);
2319 STORE_FUNCTION(cfq_fifo_expire_sync_store
, &cfqd
->cfq_fifo_expire
[1], 1, UINT_MAX
, 1);
2320 STORE_FUNCTION(cfq_fifo_expire_async_store
, &cfqd
->cfq_fifo_expire
[0], 1, UINT_MAX
, 1);
2321 STORE_FUNCTION(cfq_back_seek_max_store
, &cfqd
->cfq_back_max
, 0, UINT_MAX
, 0);
2322 STORE_FUNCTION(cfq_back_seek_penalty_store
, &cfqd
->cfq_back_penalty
, 1, UINT_MAX
, 0);
2323 STORE_FUNCTION(cfq_slice_idle_store
, &cfqd
->cfq_slice_idle
, 0, UINT_MAX
, 1);
2324 STORE_FUNCTION(cfq_slice_sync_store
, &cfqd
->cfq_slice
[1], 1, UINT_MAX
, 1);
2325 STORE_FUNCTION(cfq_slice_async_store
, &cfqd
->cfq_slice
[0], 1, UINT_MAX
, 1);
2326 STORE_FUNCTION(cfq_slice_async_rq_store
, &cfqd
->cfq_slice_async_rq
, 1, UINT_MAX
, 0);
2327 STORE_FUNCTION(cfq_max_depth_store
, &cfqd
->cfq_max_depth
, 1, UINT_MAX
, 0);
2328 #undef STORE_FUNCTION
2330 #define CFQ_ATTR(name) \
2331 __ATTR(name, S_IRUGO|S_IWUSR, cfq_##name##_show, cfq_##name##_store)
2333 static struct elv_fs_entry cfq_attrs
[] = {
2336 CFQ_ATTR(fifo_expire_sync
),
2337 CFQ_ATTR(fifo_expire_async
),
2338 CFQ_ATTR(back_seek_max
),
2339 CFQ_ATTR(back_seek_penalty
),
2340 CFQ_ATTR(slice_sync
),
2341 CFQ_ATTR(slice_async
),
2342 CFQ_ATTR(slice_async_rq
),
2343 CFQ_ATTR(slice_idle
),
2344 CFQ_ATTR(max_depth
),
2348 static struct elevator_type iosched_cfq
= {
2350 .elevator_merge_fn
= cfq_merge
,
2351 .elevator_merged_fn
= cfq_merged_request
,
2352 .elevator_merge_req_fn
= cfq_merged_requests
,
2353 .elevator_dispatch_fn
= cfq_dispatch_requests
,
2354 .elevator_add_req_fn
= cfq_insert_request
,
2355 .elevator_activate_req_fn
= cfq_activate_request
,
2356 .elevator_deactivate_req_fn
= cfq_deactivate_request
,
2357 .elevator_queue_empty_fn
= cfq_queue_empty
,
2358 .elevator_completed_req_fn
= cfq_completed_request
,
2359 .elevator_former_req_fn
= cfq_former_request
,
2360 .elevator_latter_req_fn
= cfq_latter_request
,
2361 .elevator_set_req_fn
= cfq_set_request
,
2362 .elevator_put_req_fn
= cfq_put_request
,
2363 .elevator_may_queue_fn
= cfq_may_queue
,
2364 .elevator_init_fn
= cfq_init_queue
,
2365 .elevator_exit_fn
= cfq_exit_queue
,
2368 .elevator_attrs
= cfq_attrs
,
2369 .elevator_name
= "cfq",
2370 .elevator_owner
= THIS_MODULE
,
2373 static int __init
cfq_init(void)
2378 * could be 0 on HZ < 1000 setups
2380 if (!cfq_slice_async
)
2381 cfq_slice_async
= 1;
2382 if (!cfq_slice_idle
)
2385 if (cfq_slab_setup())
2388 ret
= elv_register(&iosched_cfq
);
2395 static void __exit
cfq_exit(void)
2397 DECLARE_COMPLETION(all_gone
);
2398 elv_unregister(&iosched_cfq
);
2399 ioc_gone
= &all_gone
;
2401 if (atomic_read(&ioc_count
))
2407 module_init(cfq_init
);
2408 module_exit(cfq_exit
);
2410 MODULE_AUTHOR("Jens Axboe");
2411 MODULE_LICENSE("GPL");
2412 MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler");