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/kernel.h>
11 #include <linux/blkdev.h>
12 #include <linux/elevator.h>
13 #include <linux/bio.h>
14 #include <linux/config.h>
15 #include <linux/module.h>
16 #include <linux/slab.h>
17 #include <linux/init.h>
18 #include <linux/compiler.h>
19 #include <linux/hash.h>
20 #include <linux/rbtree.h>
21 #include <linux/mempool.h>
22 #include <linux/ioprio.h>
23 #include <linux/writeback.h>
28 static const int cfq_quantum
= 4; /* max queue in one round of service */
29 static const int cfq_queued
= 8; /* minimum rq allocate limit per-queue*/
30 static const int cfq_fifo_expire
[2] = { HZ
/ 4, HZ
/ 8 };
31 static const int cfq_back_max
= 16 * 1024; /* maximum backwards seek, in KiB */
32 static const int cfq_back_penalty
= 2; /* penalty of a backwards seek */
34 static const int cfq_slice_sync
= HZ
/ 10;
35 static int cfq_slice_async
= HZ
/ 25;
36 static const int cfq_slice_async_rq
= 2;
37 static int cfq_slice_idle
= HZ
/ 100;
39 #define CFQ_IDLE_GRACE (HZ / 10)
40 #define CFQ_SLICE_SCALE (5)
42 #define CFQ_KEY_ASYNC (0)
43 #define CFQ_KEY_ANY (0xffff)
46 * disable queueing at the driver/hardware level
48 static const int cfq_max_depth
= 2;
50 static DEFINE_RWLOCK(cfq_exit_lock
);
53 * for the hash of cfqq inside the cfqd
55 #define CFQ_QHASH_SHIFT 6
56 #define CFQ_QHASH_ENTRIES (1 << CFQ_QHASH_SHIFT)
57 #define list_entry_qhash(entry) hlist_entry((entry), struct cfq_queue, cfq_hash)
60 * for the hash of crq inside the cfqq
62 #define CFQ_MHASH_SHIFT 6
63 #define CFQ_MHASH_BLOCK(sec) ((sec) >> 3)
64 #define CFQ_MHASH_ENTRIES (1 << CFQ_MHASH_SHIFT)
65 #define CFQ_MHASH_FN(sec) hash_long(CFQ_MHASH_BLOCK(sec), CFQ_MHASH_SHIFT)
66 #define rq_hash_key(rq) ((rq)->sector + (rq)->nr_sectors)
67 #define list_entry_hash(ptr) hlist_entry((ptr), struct cfq_rq, hash)
69 #define list_entry_cfqq(ptr) list_entry((ptr), struct cfq_queue, cfq_list)
70 #define list_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
72 #define RQ_DATA(rq) (rq)->elevator_private
78 #define RB_EMPTY(node) ((node)->rb_node == NULL)
79 #define RB_CLEAR_COLOR(node) (node)->rb_color = RB_NONE
80 #define RB_CLEAR(node) do { \
81 (node)->rb_parent = NULL; \
82 RB_CLEAR_COLOR((node)); \
83 (node)->rb_right = NULL; \
84 (node)->rb_left = NULL; \
86 #define RB_CLEAR_ROOT(root) ((root)->rb_node = NULL)
87 #define rb_entry_crq(node) rb_entry((node), struct cfq_rq, rb_node)
88 #define rq_rb_key(rq) (rq)->sector
90 static kmem_cache_t
*crq_pool
;
91 static kmem_cache_t
*cfq_pool
;
92 static kmem_cache_t
*cfq_ioc_pool
;
94 static atomic_t ioc_count
= ATOMIC_INIT(0);
95 static struct completion
*ioc_gone
;
97 #define CFQ_PRIO_LISTS IOPRIO_BE_NR
98 #define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE)
99 #define cfq_class_be(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_BE)
100 #define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT)
105 #define cfq_cfqq_dispatched(cfqq) \
106 ((cfqq)->on_dispatch[ASYNC] + (cfqq)->on_dispatch[SYNC])
108 #define cfq_cfqq_class_sync(cfqq) ((cfqq)->key != CFQ_KEY_ASYNC)
110 #define cfq_cfqq_sync(cfqq) \
111 (cfq_cfqq_class_sync(cfqq) || (cfqq)->on_dispatch[SYNC])
114 * Per block device queue structure
117 request_queue_t
*queue
;
120 * rr list of queues with requests and the count of them
122 struct list_head rr_list
[CFQ_PRIO_LISTS
];
123 struct list_head busy_rr
;
124 struct list_head cur_rr
;
125 struct list_head idle_rr
;
126 unsigned int busy_queues
;
129 * non-ordered list of empty cfqq's
131 struct list_head empty_list
;
136 struct hlist_head
*cfq_hash
;
139 * global crq hash for all queues
141 struct hlist_head
*crq_hash
;
143 unsigned int max_queued
;
150 * schedule slice state info
153 * idle window management
155 struct timer_list idle_slice_timer
;
156 struct work_struct unplug_work
;
158 struct cfq_queue
*active_queue
;
159 struct cfq_io_context
*active_cic
;
160 int cur_prio
, cur_end_prio
;
161 unsigned int dispatch_slice
;
163 struct timer_list idle_class_timer
;
165 sector_t last_sector
;
166 unsigned long last_end_request
;
168 unsigned int rq_starved
;
171 * tunables, see top of file
173 unsigned int cfq_quantum
;
174 unsigned int cfq_queued
;
175 unsigned int cfq_fifo_expire
[2];
176 unsigned int cfq_back_penalty
;
177 unsigned int cfq_back_max
;
178 unsigned int cfq_slice
[2];
179 unsigned int cfq_slice_async_rq
;
180 unsigned int cfq_slice_idle
;
181 unsigned int cfq_max_depth
;
183 struct list_head cic_list
;
187 * Per process-grouping structure
190 /* reference count */
192 /* parent cfq_data */
193 struct cfq_data
*cfqd
;
194 /* cfqq lookup hash */
195 struct hlist_node cfq_hash
;
198 /* on either rr or empty list of cfqd */
199 struct list_head cfq_list
;
200 /* sorted list of pending requests */
201 struct rb_root sort_list
;
202 /* if fifo isn't expired, next request to serve */
203 struct cfq_rq
*next_crq
;
204 /* requests queued in sort_list */
206 /* currently allocated requests */
208 /* fifo list of requests in sort_list */
209 struct list_head fifo
;
211 unsigned long slice_start
;
212 unsigned long slice_end
;
213 unsigned long slice_left
;
214 unsigned long service_last
;
216 /* number of requests that are on the dispatch list */
219 /* io prio of this group */
220 unsigned short ioprio
, org_ioprio
;
221 unsigned short ioprio_class
, org_ioprio_class
;
223 /* various state flags, see below */
228 struct rb_node rb_node
;
230 struct request
*request
;
231 struct hlist_node hash
;
233 struct cfq_queue
*cfq_queue
;
234 struct cfq_io_context
*io_context
;
236 unsigned int crq_flags
;
239 enum cfqq_state_flags
{
240 CFQ_CFQQ_FLAG_on_rr
= 0,
241 CFQ_CFQQ_FLAG_wait_request
,
242 CFQ_CFQQ_FLAG_must_alloc
,
243 CFQ_CFQQ_FLAG_must_alloc_slice
,
244 CFQ_CFQQ_FLAG_must_dispatch
,
245 CFQ_CFQQ_FLAG_fifo_expire
,
246 CFQ_CFQQ_FLAG_idle_window
,
247 CFQ_CFQQ_FLAG_prio_changed
,
250 #define CFQ_CFQQ_FNS(name) \
251 static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \
253 cfqq->flags |= (1 << CFQ_CFQQ_FLAG_##name); \
255 static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \
257 cfqq->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \
259 static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \
261 return (cfqq->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \
265 CFQ_CFQQ_FNS(wait_request
);
266 CFQ_CFQQ_FNS(must_alloc
);
267 CFQ_CFQQ_FNS(must_alloc_slice
);
268 CFQ_CFQQ_FNS(must_dispatch
);
269 CFQ_CFQQ_FNS(fifo_expire
);
270 CFQ_CFQQ_FNS(idle_window
);
271 CFQ_CFQQ_FNS(prio_changed
);
274 enum cfq_rq_state_flags
{
275 CFQ_CRQ_FLAG_is_sync
= 0,
278 #define CFQ_CRQ_FNS(name) \
279 static inline void cfq_mark_crq_##name(struct cfq_rq *crq) \
281 crq->crq_flags |= (1 << CFQ_CRQ_FLAG_##name); \
283 static inline void cfq_clear_crq_##name(struct cfq_rq *crq) \
285 crq->crq_flags &= ~(1 << CFQ_CRQ_FLAG_##name); \
287 static inline int cfq_crq_##name(const struct cfq_rq *crq) \
289 return (crq->crq_flags & (1 << CFQ_CRQ_FLAG_##name)) != 0; \
292 CFQ_CRQ_FNS(is_sync
);
295 static struct cfq_queue
*cfq_find_cfq_hash(struct cfq_data
*, unsigned int, unsigned short);
296 static void cfq_dispatch_insert(request_queue_t
*, struct cfq_rq
*);
297 static struct cfq_queue
*cfq_get_queue(struct cfq_data
*cfqd
, unsigned int key
, struct task_struct
*tsk
, gfp_t gfp_mask
);
299 #define process_sync(tsk) ((tsk)->flags & PF_SYNCWRITE)
302 * lots of deadline iosched dupes, can be abstracted later...
304 static inline void cfq_del_crq_hash(struct cfq_rq
*crq
)
306 hlist_del_init(&crq
->hash
);
309 static inline void cfq_add_crq_hash(struct cfq_data
*cfqd
, struct cfq_rq
*crq
)
311 const int hash_idx
= CFQ_MHASH_FN(rq_hash_key(crq
->request
));
313 hlist_add_head(&crq
->hash
, &cfqd
->crq_hash
[hash_idx
]);
316 static struct request
*cfq_find_rq_hash(struct cfq_data
*cfqd
, sector_t offset
)
318 struct hlist_head
*hash_list
= &cfqd
->crq_hash
[CFQ_MHASH_FN(offset
)];
319 struct hlist_node
*entry
, *next
;
321 hlist_for_each_safe(entry
, next
, hash_list
) {
322 struct cfq_rq
*crq
= list_entry_hash(entry
);
323 struct request
*__rq
= crq
->request
;
325 if (!rq_mergeable(__rq
)) {
326 cfq_del_crq_hash(crq
);
330 if (rq_hash_key(__rq
) == offset
)
338 * scheduler run of queue, if there are requests pending and no one in the
339 * driver that will restart queueing
341 static inline void cfq_schedule_dispatch(struct cfq_data
*cfqd
)
343 if (cfqd
->busy_queues
)
344 kblockd_schedule_work(&cfqd
->unplug_work
);
347 static int cfq_queue_empty(request_queue_t
*q
)
349 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
351 return !cfqd
->busy_queues
;
355 * Lifted from AS - choose which of crq1 and crq2 that is best served now.
356 * We choose the request that is closest to the head right now. Distance
357 * behind the head are penalized and only allowed to a certain extent.
359 static struct cfq_rq
*
360 cfq_choose_req(struct cfq_data
*cfqd
, struct cfq_rq
*crq1
, struct cfq_rq
*crq2
)
362 sector_t last
, s1
, s2
, d1
= 0, d2
= 0;
363 int r1_wrap
= 0, r2_wrap
= 0; /* requests are behind the disk head */
364 unsigned long back_max
;
366 if (crq1
== NULL
|| crq1
== crq2
)
371 if (cfq_crq_is_sync(crq1
) && !cfq_crq_is_sync(crq2
))
373 else if (cfq_crq_is_sync(crq2
) && !cfq_crq_is_sync(crq1
))
376 s1
= crq1
->request
->sector
;
377 s2
= crq2
->request
->sector
;
379 last
= cfqd
->last_sector
;
382 * by definition, 1KiB is 2 sectors
384 back_max
= cfqd
->cfq_back_max
* 2;
387 * Strict one way elevator _except_ in the case where we allow
388 * short backward seeks which are biased as twice the cost of a
389 * similar forward seek.
393 else if (s1
+ back_max
>= last
)
394 d1
= (last
- s1
) * cfqd
->cfq_back_penalty
;
400 else if (s2
+ back_max
>= last
)
401 d2
= (last
- s2
) * cfqd
->cfq_back_penalty
;
405 /* Found required data */
406 if (!r1_wrap
&& r2_wrap
)
408 else if (!r2_wrap
&& r1_wrap
)
410 else if (r1_wrap
&& r2_wrap
) {
411 /* both behind the head */
418 /* Both requests in front of the head */
432 * would be nice to take fifo expire time into account as well
434 static struct cfq_rq
*
435 cfq_find_next_crq(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
438 struct cfq_rq
*crq_next
= NULL
, *crq_prev
= NULL
;
439 struct rb_node
*rbnext
, *rbprev
;
441 if (!(rbnext
= rb_next(&last
->rb_node
))) {
442 rbnext
= rb_first(&cfqq
->sort_list
);
443 if (rbnext
== &last
->rb_node
)
447 rbprev
= rb_prev(&last
->rb_node
);
450 crq_prev
= rb_entry_crq(rbprev
);
452 crq_next
= rb_entry_crq(rbnext
);
454 return cfq_choose_req(cfqd
, crq_next
, crq_prev
);
457 static void cfq_update_next_crq(struct cfq_rq
*crq
)
459 struct cfq_queue
*cfqq
= crq
->cfq_queue
;
461 if (cfqq
->next_crq
== crq
)
462 cfqq
->next_crq
= cfq_find_next_crq(cfqq
->cfqd
, cfqq
, crq
);
465 static void cfq_resort_rr_list(struct cfq_queue
*cfqq
, int preempted
)
467 struct cfq_data
*cfqd
= cfqq
->cfqd
;
468 struct list_head
*list
, *entry
;
470 BUG_ON(!cfq_cfqq_on_rr(cfqq
));
472 list_del(&cfqq
->cfq_list
);
474 if (cfq_class_rt(cfqq
))
475 list
= &cfqd
->cur_rr
;
476 else if (cfq_class_idle(cfqq
))
477 list
= &cfqd
->idle_rr
;
480 * if cfqq has requests in flight, don't allow it to be
481 * found in cfq_set_active_queue before it has finished them.
482 * this is done to increase fairness between a process that
483 * has lots of io pending vs one that only generates one
484 * sporadically or synchronously
486 if (cfq_cfqq_dispatched(cfqq
))
487 list
= &cfqd
->busy_rr
;
489 list
= &cfqd
->rr_list
[cfqq
->ioprio
];
493 * if queue was preempted, just add to front to be fair. busy_rr
496 if (preempted
|| list
== &cfqd
->busy_rr
) {
497 list_add(&cfqq
->cfq_list
, list
);
502 * sort by when queue was last serviced
505 while ((entry
= entry
->prev
) != list
) {
506 struct cfq_queue
*__cfqq
= list_entry_cfqq(entry
);
508 if (!__cfqq
->service_last
)
510 if (time_before(__cfqq
->service_last
, cfqq
->service_last
))
514 list_add(&cfqq
->cfq_list
, entry
);
518 * add to busy list of queues for service, trying to be fair in ordering
519 * the pending list according to last request service
522 cfq_add_cfqq_rr(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
524 BUG_ON(cfq_cfqq_on_rr(cfqq
));
525 cfq_mark_cfqq_on_rr(cfqq
);
528 cfq_resort_rr_list(cfqq
, 0);
532 cfq_del_cfqq_rr(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
534 BUG_ON(!cfq_cfqq_on_rr(cfqq
));
535 cfq_clear_cfqq_on_rr(cfqq
);
536 list_move(&cfqq
->cfq_list
, &cfqd
->empty_list
);
538 BUG_ON(!cfqd
->busy_queues
);
543 * rb tree support functions
545 static inline void cfq_del_crq_rb(struct cfq_rq
*crq
)
547 struct cfq_queue
*cfqq
= crq
->cfq_queue
;
548 struct cfq_data
*cfqd
= cfqq
->cfqd
;
549 const int sync
= cfq_crq_is_sync(crq
);
551 BUG_ON(!cfqq
->queued
[sync
]);
552 cfqq
->queued
[sync
]--;
554 cfq_update_next_crq(crq
);
556 rb_erase(&crq
->rb_node
, &cfqq
->sort_list
);
557 RB_CLEAR_COLOR(&crq
->rb_node
);
559 if (cfq_cfqq_on_rr(cfqq
) && RB_EMPTY(&cfqq
->sort_list
))
560 cfq_del_cfqq_rr(cfqd
, cfqq
);
563 static struct cfq_rq
*
564 __cfq_add_crq_rb(struct cfq_rq
*crq
)
566 struct rb_node
**p
= &crq
->cfq_queue
->sort_list
.rb_node
;
567 struct rb_node
*parent
= NULL
;
568 struct cfq_rq
*__crq
;
572 __crq
= rb_entry_crq(parent
);
574 if (crq
->rb_key
< __crq
->rb_key
)
576 else if (crq
->rb_key
> __crq
->rb_key
)
582 rb_link_node(&crq
->rb_node
, parent
, p
);
586 static void cfq_add_crq_rb(struct cfq_rq
*crq
)
588 struct cfq_queue
*cfqq
= crq
->cfq_queue
;
589 struct cfq_data
*cfqd
= cfqq
->cfqd
;
590 struct request
*rq
= crq
->request
;
591 struct cfq_rq
*__alias
;
593 crq
->rb_key
= rq_rb_key(rq
);
594 cfqq
->queued
[cfq_crq_is_sync(crq
)]++;
597 * looks a little odd, but the first insert might return an alias.
598 * if that happens, put the alias on the dispatch list
600 while ((__alias
= __cfq_add_crq_rb(crq
)) != NULL
)
601 cfq_dispatch_insert(cfqd
->queue
, __alias
);
603 rb_insert_color(&crq
->rb_node
, &cfqq
->sort_list
);
605 if (!cfq_cfqq_on_rr(cfqq
))
606 cfq_add_cfqq_rr(cfqd
, cfqq
);
609 * check if this request is a better next-serve candidate
611 cfqq
->next_crq
= cfq_choose_req(cfqd
, cfqq
->next_crq
, crq
);
615 cfq_reposition_crq_rb(struct cfq_queue
*cfqq
, struct cfq_rq
*crq
)
617 rb_erase(&crq
->rb_node
, &cfqq
->sort_list
);
618 cfqq
->queued
[cfq_crq_is_sync(crq
)]--;
623 static struct request
*cfq_find_rq_rb(struct cfq_data
*cfqd
, sector_t sector
)
626 struct cfq_queue
*cfqq
= cfq_find_cfq_hash(cfqd
, current
->pid
, CFQ_KEY_ANY
);
632 n
= cfqq
->sort_list
.rb_node
;
634 struct cfq_rq
*crq
= rb_entry_crq(n
);
636 if (sector
< crq
->rb_key
)
638 else if (sector
> crq
->rb_key
)
648 static void cfq_activate_request(request_queue_t
*q
, struct request
*rq
)
650 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
652 cfqd
->rq_in_driver
++;
655 static void cfq_deactivate_request(request_queue_t
*q
, struct request
*rq
)
657 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
659 WARN_ON(!cfqd
->rq_in_driver
);
660 cfqd
->rq_in_driver
--;
663 static void cfq_remove_request(struct request
*rq
)
665 struct cfq_rq
*crq
= RQ_DATA(rq
);
667 list_del_init(&rq
->queuelist
);
669 cfq_del_crq_hash(crq
);
673 cfq_merge(request_queue_t
*q
, struct request
**req
, struct bio
*bio
)
675 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
676 struct request
*__rq
;
679 __rq
= cfq_find_rq_hash(cfqd
, bio
->bi_sector
);
680 if (__rq
&& elv_rq_merge_ok(__rq
, bio
)) {
681 ret
= ELEVATOR_BACK_MERGE
;
685 __rq
= cfq_find_rq_rb(cfqd
, bio
->bi_sector
+ bio_sectors(bio
));
686 if (__rq
&& elv_rq_merge_ok(__rq
, bio
)) {
687 ret
= ELEVATOR_FRONT_MERGE
;
691 return ELEVATOR_NO_MERGE
;
697 static void cfq_merged_request(request_queue_t
*q
, struct request
*req
)
699 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
700 struct cfq_rq
*crq
= RQ_DATA(req
);
702 cfq_del_crq_hash(crq
);
703 cfq_add_crq_hash(cfqd
, crq
);
705 if (rq_rb_key(req
) != crq
->rb_key
) {
706 struct cfq_queue
*cfqq
= crq
->cfq_queue
;
708 cfq_update_next_crq(crq
);
709 cfq_reposition_crq_rb(cfqq
, crq
);
714 cfq_merged_requests(request_queue_t
*q
, struct request
*rq
,
715 struct request
*next
)
717 cfq_merged_request(q
, rq
);
720 * reposition in fifo if next is older than rq
722 if (!list_empty(&rq
->queuelist
) && !list_empty(&next
->queuelist
) &&
723 time_before(next
->start_time
, rq
->start_time
))
724 list_move(&rq
->queuelist
, &next
->queuelist
);
726 cfq_remove_request(next
);
730 __cfq_set_active_queue(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
734 * stop potential idle class queues waiting service
736 del_timer(&cfqd
->idle_class_timer
);
738 cfqq
->slice_start
= jiffies
;
740 cfqq
->slice_left
= 0;
741 cfq_clear_cfqq_must_alloc_slice(cfqq
);
742 cfq_clear_cfqq_fifo_expire(cfqq
);
745 cfqd
->active_queue
= cfqq
;
749 * current cfqq expired its slice (or was too idle), select new one
752 __cfq_slice_expired(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
755 unsigned long now
= jiffies
;
757 if (cfq_cfqq_wait_request(cfqq
))
758 del_timer(&cfqd
->idle_slice_timer
);
760 if (!preempted
&& !cfq_cfqq_dispatched(cfqq
)) {
761 cfqq
->service_last
= now
;
762 cfq_schedule_dispatch(cfqd
);
765 cfq_clear_cfqq_must_dispatch(cfqq
);
766 cfq_clear_cfqq_wait_request(cfqq
);
769 * store what was left of this slice, if the queue idled out
772 if (time_after(cfqq
->slice_end
, now
))
773 cfqq
->slice_left
= cfqq
->slice_end
- now
;
775 cfqq
->slice_left
= 0;
777 if (cfq_cfqq_on_rr(cfqq
))
778 cfq_resort_rr_list(cfqq
, preempted
);
780 if (cfqq
== cfqd
->active_queue
)
781 cfqd
->active_queue
= NULL
;
783 if (cfqd
->active_cic
) {
784 put_io_context(cfqd
->active_cic
->ioc
);
785 cfqd
->active_cic
= NULL
;
788 cfqd
->dispatch_slice
= 0;
791 static inline void cfq_slice_expired(struct cfq_data
*cfqd
, int preempted
)
793 struct cfq_queue
*cfqq
= cfqd
->active_queue
;
796 __cfq_slice_expired(cfqd
, cfqq
, preempted
);
809 static int cfq_get_next_prio_level(struct cfq_data
*cfqd
)
818 for (p
= cfqd
->cur_prio
; p
<= cfqd
->cur_end_prio
; p
++) {
819 if (!list_empty(&cfqd
->rr_list
[p
])) {
828 if (++cfqd
->cur_end_prio
== CFQ_PRIO_LISTS
) {
829 cfqd
->cur_end_prio
= 0;
836 if (unlikely(prio
== -1))
839 BUG_ON(prio
>= CFQ_PRIO_LISTS
);
841 list_splice_init(&cfqd
->rr_list
[prio
], &cfqd
->cur_rr
);
843 cfqd
->cur_prio
= prio
+ 1;
844 if (cfqd
->cur_prio
> cfqd
->cur_end_prio
) {
845 cfqd
->cur_end_prio
= cfqd
->cur_prio
;
848 if (cfqd
->cur_end_prio
== CFQ_PRIO_LISTS
) {
850 cfqd
->cur_end_prio
= 0;
856 static struct cfq_queue
*cfq_set_active_queue(struct cfq_data
*cfqd
)
858 struct cfq_queue
*cfqq
= NULL
;
861 * if current list is non-empty, grab first entry. if it is empty,
862 * get next prio level and grab first entry then if any are spliced
864 if (!list_empty(&cfqd
->cur_rr
) || cfq_get_next_prio_level(cfqd
) != -1)
865 cfqq
= list_entry_cfqq(cfqd
->cur_rr
.next
);
868 * if we have idle queues and no rt or be queues had pending
869 * requests, either allow immediate service if the grace period
870 * has passed or arm the idle grace timer
872 if (!cfqq
&& !list_empty(&cfqd
->idle_rr
)) {
873 unsigned long end
= cfqd
->last_end_request
+ CFQ_IDLE_GRACE
;
875 if (time_after_eq(jiffies
, end
))
876 cfqq
= list_entry_cfqq(cfqd
->idle_rr
.next
);
878 mod_timer(&cfqd
->idle_class_timer
, end
);
881 __cfq_set_active_queue(cfqd
, cfqq
);
885 static int cfq_arm_slice_timer(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
890 WARN_ON(!RB_EMPTY(&cfqq
->sort_list
));
891 WARN_ON(cfqq
!= cfqd
->active_queue
);
894 * idle is disabled, either manually or by past process history
896 if (!cfqd
->cfq_slice_idle
)
898 if (!cfq_cfqq_idle_window(cfqq
))
901 * task has exited, don't wait
903 if (cfqd
->active_cic
&& !cfqd
->active_cic
->ioc
->task
)
906 cfq_mark_cfqq_must_dispatch(cfqq
);
907 cfq_mark_cfqq_wait_request(cfqq
);
909 sl
= min(cfqq
->slice_end
- 1, (unsigned long) cfqd
->cfq_slice_idle
);
910 mod_timer(&cfqd
->idle_slice_timer
, jiffies
+ sl
);
914 static void cfq_dispatch_insert(request_queue_t
*q
, struct cfq_rq
*crq
)
916 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
917 struct cfq_queue
*cfqq
= crq
->cfq_queue
;
919 cfqq
->next_crq
= cfq_find_next_crq(cfqd
, cfqq
, crq
);
920 cfq_remove_request(crq
->request
);
921 cfqq
->on_dispatch
[cfq_crq_is_sync(crq
)]++;
922 elv_dispatch_sort(q
, crq
->request
);
926 * return expired entry, or NULL to just start from scratch in rbtree
928 static inline struct cfq_rq
*cfq_check_fifo(struct cfq_queue
*cfqq
)
930 struct cfq_data
*cfqd
= cfqq
->cfqd
;
934 if (cfq_cfqq_fifo_expire(cfqq
))
937 if (!list_empty(&cfqq
->fifo
)) {
938 int fifo
= cfq_cfqq_class_sync(cfqq
);
940 crq
= RQ_DATA(list_entry_fifo(cfqq
->fifo
.next
));
942 if (time_after(jiffies
, rq
->start_time
+ cfqd
->cfq_fifo_expire
[fifo
])) {
943 cfq_mark_cfqq_fifo_expire(cfqq
);
952 * Scale schedule slice based on io priority. Use the sync time slice only
953 * if a queue is marked sync and has sync io queued. A sync queue with async
954 * io only, should not get full sync slice length.
957 cfq_prio_to_slice(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
959 const int base_slice
= cfqd
->cfq_slice
[cfq_cfqq_sync(cfqq
)];
961 WARN_ON(cfqq
->ioprio
>= IOPRIO_BE_NR
);
963 return base_slice
+ (base_slice
/CFQ_SLICE_SCALE
* (4 - cfqq
->ioprio
));
967 cfq_set_prio_slice(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
969 cfqq
->slice_end
= cfq_prio_to_slice(cfqd
, cfqq
) + jiffies
;
973 cfq_prio_to_maxrq(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
975 const int base_rq
= cfqd
->cfq_slice_async_rq
;
977 WARN_ON(cfqq
->ioprio
>= IOPRIO_BE_NR
);
979 return 2 * (base_rq
+ base_rq
* (CFQ_PRIO_LISTS
- 1 - cfqq
->ioprio
));
983 * get next queue for service
985 static struct cfq_queue
*cfq_select_queue(struct cfq_data
*cfqd
)
987 unsigned long now
= jiffies
;
988 struct cfq_queue
*cfqq
;
990 cfqq
= cfqd
->active_queue
;
997 if (!cfq_cfqq_must_dispatch(cfqq
) && time_after(now
, cfqq
->slice_end
))
1001 * if queue has requests, dispatch one. if not, check if
1002 * enough slice is left to wait for one
1004 if (!RB_EMPTY(&cfqq
->sort_list
))
1006 else if (cfq_cfqq_class_sync(cfqq
) &&
1007 time_before(now
, cfqq
->slice_end
)) {
1008 if (cfq_arm_slice_timer(cfqd
, cfqq
))
1013 cfq_slice_expired(cfqd
, 0);
1015 cfqq
= cfq_set_active_queue(cfqd
);
1021 __cfq_dispatch_requests(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
1026 BUG_ON(RB_EMPTY(&cfqq
->sort_list
));
1032 * follow expired path, else get first next available
1034 if ((crq
= cfq_check_fifo(cfqq
)) == NULL
)
1035 crq
= cfqq
->next_crq
;
1038 * finally, insert request into driver dispatch list
1040 cfq_dispatch_insert(cfqd
->queue
, crq
);
1042 cfqd
->dispatch_slice
++;
1045 if (!cfqd
->active_cic
) {
1046 atomic_inc(&crq
->io_context
->ioc
->refcount
);
1047 cfqd
->active_cic
= crq
->io_context
;
1050 if (RB_EMPTY(&cfqq
->sort_list
))
1053 } while (dispatched
< max_dispatch
);
1056 * if slice end isn't set yet, set it. if at least one request was
1057 * sync, use the sync time slice value
1059 if (!cfqq
->slice_end
)
1060 cfq_set_prio_slice(cfqd
, cfqq
);
1063 * expire an async queue immediately if it has used up its slice. idle
1064 * queue always expire after 1 dispatch round.
1066 if ((!cfq_cfqq_sync(cfqq
) &&
1067 cfqd
->dispatch_slice
>= cfq_prio_to_maxrq(cfqd
, cfqq
)) ||
1068 cfq_class_idle(cfqq
))
1069 cfq_slice_expired(cfqd
, 0);
1075 cfq_forced_dispatch_cfqqs(struct list_head
*list
)
1078 struct cfq_queue
*cfqq
, *next
;
1081 list_for_each_entry_safe(cfqq
, next
, list
, cfq_list
) {
1082 while ((crq
= cfqq
->next_crq
)) {
1083 cfq_dispatch_insert(cfqq
->cfqd
->queue
, crq
);
1086 BUG_ON(!list_empty(&cfqq
->fifo
));
1092 cfq_forced_dispatch(struct cfq_data
*cfqd
)
1094 int i
, dispatched
= 0;
1096 for (i
= 0; i
< CFQ_PRIO_LISTS
; i
++)
1097 dispatched
+= cfq_forced_dispatch_cfqqs(&cfqd
->rr_list
[i
]);
1099 dispatched
+= cfq_forced_dispatch_cfqqs(&cfqd
->busy_rr
);
1100 dispatched
+= cfq_forced_dispatch_cfqqs(&cfqd
->cur_rr
);
1101 dispatched
+= cfq_forced_dispatch_cfqqs(&cfqd
->idle_rr
);
1103 cfq_slice_expired(cfqd
, 0);
1105 BUG_ON(cfqd
->busy_queues
);
1111 cfq_dispatch_requests(request_queue_t
*q
, int force
)
1113 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
1114 struct cfq_queue
*cfqq
;
1116 if (!cfqd
->busy_queues
)
1119 if (unlikely(force
))
1120 return cfq_forced_dispatch(cfqd
);
1122 cfqq
= cfq_select_queue(cfqd
);
1127 * if idle window is disabled, allow queue buildup
1129 if (!cfq_cfqq_idle_window(cfqq
) &&
1130 cfqd
->rq_in_driver
>= cfqd
->cfq_max_depth
)
1133 cfq_clear_cfqq_must_dispatch(cfqq
);
1134 cfq_clear_cfqq_wait_request(cfqq
);
1135 del_timer(&cfqd
->idle_slice_timer
);
1137 max_dispatch
= cfqd
->cfq_quantum
;
1138 if (cfq_class_idle(cfqq
))
1141 return __cfq_dispatch_requests(cfqd
, cfqq
, max_dispatch
);
1148 * task holds one reference to the queue, dropped when task exits. each crq
1149 * in-flight on this queue also holds a reference, dropped when crq is freed.
1151 * queue lock must be held here.
1153 static void cfq_put_queue(struct cfq_queue
*cfqq
)
1155 struct cfq_data
*cfqd
= cfqq
->cfqd
;
1157 BUG_ON(atomic_read(&cfqq
->ref
) <= 0);
1159 if (!atomic_dec_and_test(&cfqq
->ref
))
1162 BUG_ON(rb_first(&cfqq
->sort_list
));
1163 BUG_ON(cfqq
->allocated
[READ
] + cfqq
->allocated
[WRITE
]);
1164 BUG_ON(cfq_cfqq_on_rr(cfqq
));
1166 if (unlikely(cfqd
->active_queue
== cfqq
))
1167 __cfq_slice_expired(cfqd
, cfqq
, 0);
1170 * it's on the empty list and still hashed
1172 list_del(&cfqq
->cfq_list
);
1173 hlist_del(&cfqq
->cfq_hash
);
1174 kmem_cache_free(cfq_pool
, cfqq
);
1177 static inline struct cfq_queue
*
1178 __cfq_find_cfq_hash(struct cfq_data
*cfqd
, unsigned int key
, unsigned int prio
,
1181 struct hlist_head
*hash_list
= &cfqd
->cfq_hash
[hashval
];
1182 struct hlist_node
*entry
, *next
;
1184 hlist_for_each_safe(entry
, next
, hash_list
) {
1185 struct cfq_queue
*__cfqq
= list_entry_qhash(entry
);
1186 const unsigned short __p
= IOPRIO_PRIO_VALUE(__cfqq
->org_ioprio_class
, __cfqq
->org_ioprio
);
1188 if (__cfqq
->key
== key
&& (__p
== prio
|| prio
== CFQ_KEY_ANY
))
1195 static struct cfq_queue
*
1196 cfq_find_cfq_hash(struct cfq_data
*cfqd
, unsigned int key
, unsigned short prio
)
1198 return __cfq_find_cfq_hash(cfqd
, key
, prio
, hash_long(key
, CFQ_QHASH_SHIFT
));
1201 static void cfq_free_io_context(struct cfq_io_context
*cic
)
1203 struct cfq_io_context
*__cic
;
1204 struct list_head
*entry
, *next
;
1207 list_for_each_safe(entry
, next
, &cic
->list
) {
1208 __cic
= list_entry(entry
, struct cfq_io_context
, list
);
1209 kmem_cache_free(cfq_ioc_pool
, __cic
);
1213 kmem_cache_free(cfq_ioc_pool
, cic
);
1214 if (atomic_sub_and_test(freed
, &ioc_count
) && ioc_gone
)
1218 static void cfq_trim(struct io_context
*ioc
)
1220 ioc
->set_ioprio
= NULL
;
1222 cfq_free_io_context(ioc
->cic
);
1226 * Called with interrupts disabled
1228 static void cfq_exit_single_io_context(struct cfq_io_context
*cic
)
1230 struct cfq_data
*cfqd
= cic
->key
;
1238 WARN_ON(!irqs_disabled());
1240 spin_lock(q
->queue_lock
);
1242 if (cic
->cfqq
[ASYNC
]) {
1243 if (unlikely(cic
->cfqq
[ASYNC
] == cfqd
->active_queue
))
1244 __cfq_slice_expired(cfqd
, cic
->cfqq
[ASYNC
], 0);
1245 cfq_put_queue(cic
->cfqq
[ASYNC
]);
1246 cic
->cfqq
[ASYNC
] = NULL
;
1249 if (cic
->cfqq
[SYNC
]) {
1250 if (unlikely(cic
->cfqq
[SYNC
] == cfqd
->active_queue
))
1251 __cfq_slice_expired(cfqd
, cic
->cfqq
[SYNC
], 0);
1252 cfq_put_queue(cic
->cfqq
[SYNC
]);
1253 cic
->cfqq
[SYNC
] = NULL
;
1257 list_del_init(&cic
->queue_list
);
1258 spin_unlock(q
->queue_lock
);
1262 * Another task may update the task cic list, if it is doing a queue lookup
1263 * on its behalf. cfq_cic_lock excludes such concurrent updates
1265 static void cfq_exit_io_context(struct cfq_io_context
*cic
)
1267 struct cfq_io_context
*__cic
;
1268 struct list_head
*entry
;
1269 unsigned long flags
;
1271 local_irq_save(flags
);
1274 * put the reference this task is holding to the various queues
1276 read_lock(&cfq_exit_lock
);
1277 list_for_each(entry
, &cic
->list
) {
1278 __cic
= list_entry(entry
, struct cfq_io_context
, list
);
1279 cfq_exit_single_io_context(__cic
);
1282 cfq_exit_single_io_context(cic
);
1283 read_unlock(&cfq_exit_lock
);
1284 local_irq_restore(flags
);
1287 static struct cfq_io_context
*
1288 cfq_alloc_io_context(struct cfq_data
*cfqd
, gfp_t gfp_mask
)
1290 struct cfq_io_context
*cic
= kmem_cache_alloc(cfq_ioc_pool
, gfp_mask
);
1293 INIT_LIST_HEAD(&cic
->list
);
1294 cic
->cfqq
[ASYNC
] = NULL
;
1295 cic
->cfqq
[SYNC
] = NULL
;
1297 cic
->last_end_request
= jiffies
;
1298 cic
->ttime_total
= 0;
1299 cic
->ttime_samples
= 0;
1300 cic
->ttime_mean
= 0;
1301 cic
->dtor
= cfq_free_io_context
;
1302 cic
->exit
= cfq_exit_io_context
;
1303 INIT_LIST_HEAD(&cic
->queue_list
);
1304 atomic_inc(&ioc_count
);
1310 static void cfq_init_prio_data(struct cfq_queue
*cfqq
)
1312 struct task_struct
*tsk
= current
;
1315 if (!cfq_cfqq_prio_changed(cfqq
))
1318 ioprio_class
= IOPRIO_PRIO_CLASS(tsk
->ioprio
);
1319 switch (ioprio_class
) {
1321 printk(KERN_ERR
"cfq: bad prio %x\n", ioprio_class
);
1322 case IOPRIO_CLASS_NONE
:
1324 * no prio set, place us in the middle of the BE classes
1326 cfqq
->ioprio
= task_nice_ioprio(tsk
);
1327 cfqq
->ioprio_class
= IOPRIO_CLASS_BE
;
1329 case IOPRIO_CLASS_RT
:
1330 cfqq
->ioprio
= task_ioprio(tsk
);
1331 cfqq
->ioprio_class
= IOPRIO_CLASS_RT
;
1333 case IOPRIO_CLASS_BE
:
1334 cfqq
->ioprio
= task_ioprio(tsk
);
1335 cfqq
->ioprio_class
= IOPRIO_CLASS_BE
;
1337 case IOPRIO_CLASS_IDLE
:
1338 cfqq
->ioprio_class
= IOPRIO_CLASS_IDLE
;
1340 cfq_clear_cfqq_idle_window(cfqq
);
1345 * keep track of original prio settings in case we have to temporarily
1346 * elevate the priority of this queue
1348 cfqq
->org_ioprio
= cfqq
->ioprio
;
1349 cfqq
->org_ioprio_class
= cfqq
->ioprio_class
;
1351 if (cfq_cfqq_on_rr(cfqq
))
1352 cfq_resort_rr_list(cfqq
, 0);
1354 cfq_clear_cfqq_prio_changed(cfqq
);
1357 static inline void changed_ioprio(struct cfq_io_context
*cic
)
1359 struct cfq_data
*cfqd
= cic
->key
;
1360 struct cfq_queue
*cfqq
;
1362 spin_lock(cfqd
->queue
->queue_lock
);
1363 cfqq
= cic
->cfqq
[ASYNC
];
1365 struct cfq_queue
*new_cfqq
;
1366 new_cfqq
= cfq_get_queue(cfqd
, CFQ_KEY_ASYNC
,
1367 cic
->ioc
->task
, GFP_ATOMIC
);
1369 cic
->cfqq
[ASYNC
] = new_cfqq
;
1370 cfq_put_queue(cfqq
);
1373 cfqq
= cic
->cfqq
[SYNC
];
1375 cfq_mark_cfqq_prio_changed(cfqq
);
1376 cfq_init_prio_data(cfqq
);
1378 spin_unlock(cfqd
->queue
->queue_lock
);
1383 * callback from sys_ioprio_set, irqs are disabled
1385 static int cfq_ioc_set_ioprio(struct io_context
*ioc
, unsigned int ioprio
)
1387 struct cfq_io_context
*cic
;
1389 write_lock(&cfq_exit_lock
);
1393 changed_ioprio(cic
);
1395 list_for_each_entry(cic
, &cic
->list
, list
)
1396 changed_ioprio(cic
);
1398 write_unlock(&cfq_exit_lock
);
1403 static struct cfq_queue
*
1404 cfq_get_queue(struct cfq_data
*cfqd
, unsigned int key
, struct task_struct
*tsk
,
1407 const int hashval
= hash_long(key
, CFQ_QHASH_SHIFT
);
1408 struct cfq_queue
*cfqq
, *new_cfqq
= NULL
;
1409 unsigned short ioprio
;
1412 ioprio
= tsk
->ioprio
;
1413 cfqq
= __cfq_find_cfq_hash(cfqd
, key
, ioprio
, hashval
);
1419 } else if (gfp_mask
& __GFP_WAIT
) {
1420 spin_unlock_irq(cfqd
->queue
->queue_lock
);
1421 new_cfqq
= kmem_cache_alloc(cfq_pool
, gfp_mask
);
1422 spin_lock_irq(cfqd
->queue
->queue_lock
);
1425 cfqq
= kmem_cache_alloc(cfq_pool
, gfp_mask
);
1430 memset(cfqq
, 0, sizeof(*cfqq
));
1432 INIT_HLIST_NODE(&cfqq
->cfq_hash
);
1433 INIT_LIST_HEAD(&cfqq
->cfq_list
);
1434 RB_CLEAR_ROOT(&cfqq
->sort_list
);
1435 INIT_LIST_HEAD(&cfqq
->fifo
);
1438 hlist_add_head(&cfqq
->cfq_hash
, &cfqd
->cfq_hash
[hashval
]);
1439 atomic_set(&cfqq
->ref
, 0);
1441 cfqq
->service_last
= 0;
1443 * set ->slice_left to allow preemption for a new process
1445 cfqq
->slice_left
= 2 * cfqd
->cfq_slice_idle
;
1446 cfq_mark_cfqq_idle_window(cfqq
);
1447 cfq_mark_cfqq_prio_changed(cfqq
);
1448 cfq_init_prio_data(cfqq
);
1452 kmem_cache_free(cfq_pool
, new_cfqq
);
1454 atomic_inc(&cfqq
->ref
);
1456 WARN_ON((gfp_mask
& __GFP_WAIT
) && !cfqq
);
1461 * Setup general io context and cfq io context. There can be several cfq
1462 * io contexts per general io context, if this process is doing io to more
1463 * than one device managed by cfq. Note that caller is holding a reference to
1464 * cfqq, so we don't need to worry about it disappearing
1466 static struct cfq_io_context
*
1467 cfq_get_io_context(struct cfq_data
*cfqd
, pid_t pid
, gfp_t gfp_mask
)
1469 struct io_context
*ioc
= NULL
;
1470 struct cfq_io_context
*cic
;
1472 might_sleep_if(gfp_mask
& __GFP_WAIT
);
1474 ioc
= get_io_context(gfp_mask
);
1479 if ((cic
= ioc
->cic
) == NULL
) {
1480 cic
= cfq_alloc_io_context(cfqd
, gfp_mask
);
1486 * manually increment generic io_context usage count, it
1487 * cannot go away since we are already holding one ref to it
1491 read_lock(&cfq_exit_lock
);
1492 ioc
->set_ioprio
= cfq_ioc_set_ioprio
;
1494 list_add(&cic
->queue_list
, &cfqd
->cic_list
);
1495 read_unlock(&cfq_exit_lock
);
1497 struct cfq_io_context
*__cic
;
1500 * the first cic on the list is actually the head itself
1502 if (cic
->key
== cfqd
)
1505 if (unlikely(!cic
->key
)) {
1506 read_lock(&cfq_exit_lock
);
1507 if (list_empty(&cic
->list
))
1510 ioc
->cic
= list_entry(cic
->list
.next
,
1511 struct cfq_io_context
,
1513 read_unlock(&cfq_exit_lock
);
1514 kmem_cache_free(cfq_ioc_pool
, cic
);
1515 atomic_dec(&ioc_count
);
1520 * cic exists, check if we already are there. linear search
1521 * should be ok here, the list will usually not be more than
1522 * 1 or a few entries long
1524 list_for_each_entry(__cic
, &cic
->list
, list
) {
1526 * this process is already holding a reference to
1527 * this queue, so no need to get one more
1529 if (__cic
->key
== cfqd
) {
1533 if (unlikely(!__cic
->key
)) {
1534 read_lock(&cfq_exit_lock
);
1535 list_del(&__cic
->list
);
1536 read_unlock(&cfq_exit_lock
);
1537 kmem_cache_free(cfq_ioc_pool
, __cic
);
1538 atomic_dec(&ioc_count
);
1544 * nope, process doesn't have a cic assoicated with this
1545 * cfqq yet. get a new one and add to list
1547 __cic
= cfq_alloc_io_context(cfqd
, gfp_mask
);
1553 read_lock(&cfq_exit_lock
);
1554 list_add(&__cic
->list
, &cic
->list
);
1555 list_add(&__cic
->queue_list
, &cfqd
->cic_list
);
1556 read_unlock(&cfq_exit_lock
);
1563 put_io_context(ioc
);
1568 cfq_update_io_thinktime(struct cfq_data
*cfqd
, struct cfq_io_context
*cic
)
1570 unsigned long elapsed
, ttime
;
1573 * if this context already has stuff queued, thinktime is from
1574 * last queue not last end
1577 if (time_after(cic
->last_end_request
, cic
->last_queue
))
1578 elapsed
= jiffies
- cic
->last_end_request
;
1580 elapsed
= jiffies
- cic
->last_queue
;
1582 elapsed
= jiffies
- cic
->last_end_request
;
1585 ttime
= min(elapsed
, 2UL * cfqd
->cfq_slice_idle
);
1587 cic
->ttime_samples
= (7*cic
->ttime_samples
+ 256) / 8;
1588 cic
->ttime_total
= (7*cic
->ttime_total
+ 256*ttime
) / 8;
1589 cic
->ttime_mean
= (cic
->ttime_total
+ 128) / cic
->ttime_samples
;
1592 #define sample_valid(samples) ((samples) > 80)
1595 * Disable idle window if the process thinks too long or seeks so much that
1599 cfq_update_idle_window(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
1600 struct cfq_io_context
*cic
)
1602 int enable_idle
= cfq_cfqq_idle_window(cfqq
);
1604 if (!cic
->ioc
->task
|| !cfqd
->cfq_slice_idle
)
1606 else if (sample_valid(cic
->ttime_samples
)) {
1607 if (cic
->ttime_mean
> cfqd
->cfq_slice_idle
)
1614 cfq_mark_cfqq_idle_window(cfqq
);
1616 cfq_clear_cfqq_idle_window(cfqq
);
1621 * Check if new_cfqq should preempt the currently active queue. Return 0 for
1622 * no or if we aren't sure, a 1 will cause a preempt.
1625 cfq_should_preempt(struct cfq_data
*cfqd
, struct cfq_queue
*new_cfqq
,
1628 struct cfq_queue
*cfqq
= cfqd
->active_queue
;
1630 if (cfq_class_idle(new_cfqq
))
1636 if (cfq_class_idle(cfqq
))
1638 if (!cfq_cfqq_wait_request(new_cfqq
))
1641 * if it doesn't have slice left, forget it
1643 if (new_cfqq
->slice_left
< cfqd
->cfq_slice_idle
)
1645 if (cfq_crq_is_sync(crq
) && !cfq_cfqq_sync(cfqq
))
1652 * cfqq preempts the active queue. if we allowed preempt with no slice left,
1653 * let it have half of its nominal slice.
1655 static void cfq_preempt_queue(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
1657 struct cfq_queue
*__cfqq
, *next
;
1659 list_for_each_entry_safe(__cfqq
, next
, &cfqd
->cur_rr
, cfq_list
)
1660 cfq_resort_rr_list(__cfqq
, 1);
1662 if (!cfqq
->slice_left
)
1663 cfqq
->slice_left
= cfq_prio_to_slice(cfqd
, cfqq
) / 2;
1665 cfqq
->slice_end
= cfqq
->slice_left
+ jiffies
;
1666 __cfq_slice_expired(cfqd
, cfqq
, 1);
1667 __cfq_set_active_queue(cfqd
, cfqq
);
1671 * should really be a ll_rw_blk.c helper
1673 static void cfq_start_queueing(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
1675 request_queue_t
*q
= cfqd
->queue
;
1677 if (!blk_queue_plugged(q
))
1680 __generic_unplug_device(q
);
1684 * Called when a new fs request (crq) is added (to cfqq). Check if there's
1685 * something we should do about it
1688 cfq_crq_enqueued(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
1691 struct cfq_io_context
*cic
;
1693 cfqq
->next_crq
= cfq_choose_req(cfqd
, cfqq
->next_crq
, crq
);
1696 * we never wait for an async request and we don't allow preemption
1697 * of an async request. so just return early
1699 if (!cfq_crq_is_sync(crq
))
1702 cic
= crq
->io_context
;
1704 cfq_update_io_thinktime(cfqd
, cic
);
1705 cfq_update_idle_window(cfqd
, cfqq
, cic
);
1707 cic
->last_queue
= jiffies
;
1709 if (cfqq
== cfqd
->active_queue
) {
1711 * if we are waiting for a request for this queue, let it rip
1712 * immediately and flag that we must not expire this queue
1715 if (cfq_cfqq_wait_request(cfqq
)) {
1716 cfq_mark_cfqq_must_dispatch(cfqq
);
1717 del_timer(&cfqd
->idle_slice_timer
);
1718 cfq_start_queueing(cfqd
, cfqq
);
1720 } else if (cfq_should_preempt(cfqd
, cfqq
, crq
)) {
1722 * not the active queue - expire current slice if it is
1723 * idle and has expired it's mean thinktime or this new queue
1724 * has some old slice time left and is of higher priority
1726 cfq_preempt_queue(cfqd
, cfqq
);
1727 cfq_mark_cfqq_must_dispatch(cfqq
);
1728 cfq_start_queueing(cfqd
, cfqq
);
1732 static void cfq_insert_request(request_queue_t
*q
, struct request
*rq
)
1734 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
1735 struct cfq_rq
*crq
= RQ_DATA(rq
);
1736 struct cfq_queue
*cfqq
= crq
->cfq_queue
;
1738 cfq_init_prio_data(cfqq
);
1740 cfq_add_crq_rb(crq
);
1742 list_add_tail(&rq
->queuelist
, &cfqq
->fifo
);
1744 if (rq_mergeable(rq
))
1745 cfq_add_crq_hash(cfqd
, crq
);
1747 cfq_crq_enqueued(cfqd
, cfqq
, crq
);
1750 static void cfq_completed_request(request_queue_t
*q
, struct request
*rq
)
1752 struct cfq_rq
*crq
= RQ_DATA(rq
);
1753 struct cfq_queue
*cfqq
= crq
->cfq_queue
;
1754 struct cfq_data
*cfqd
= cfqq
->cfqd
;
1755 const int sync
= cfq_crq_is_sync(crq
);
1760 WARN_ON(!cfqd
->rq_in_driver
);
1761 WARN_ON(!cfqq
->on_dispatch
[sync
]);
1762 cfqd
->rq_in_driver
--;
1763 cfqq
->on_dispatch
[sync
]--;
1765 if (!cfq_class_idle(cfqq
))
1766 cfqd
->last_end_request
= now
;
1768 if (!cfq_cfqq_dispatched(cfqq
)) {
1769 if (cfq_cfqq_on_rr(cfqq
)) {
1770 cfqq
->service_last
= now
;
1771 cfq_resort_rr_list(cfqq
, 0);
1773 cfq_schedule_dispatch(cfqd
);
1776 if (cfq_crq_is_sync(crq
))
1777 crq
->io_context
->last_end_request
= now
;
1780 static struct request
*
1781 cfq_former_request(request_queue_t
*q
, struct request
*rq
)
1783 struct cfq_rq
*crq
= RQ_DATA(rq
);
1784 struct rb_node
*rbprev
= rb_prev(&crq
->rb_node
);
1787 return rb_entry_crq(rbprev
)->request
;
1792 static struct request
*
1793 cfq_latter_request(request_queue_t
*q
, struct request
*rq
)
1795 struct cfq_rq
*crq
= RQ_DATA(rq
);
1796 struct rb_node
*rbnext
= rb_next(&crq
->rb_node
);
1799 return rb_entry_crq(rbnext
)->request
;
1805 * we temporarily boost lower priority queues if they are holding fs exclusive
1806 * resources. they are boosted to normal prio (CLASS_BE/4)
1808 static void cfq_prio_boost(struct cfq_queue
*cfqq
)
1810 const int ioprio_class
= cfqq
->ioprio_class
;
1811 const int ioprio
= cfqq
->ioprio
;
1813 if (has_fs_excl()) {
1815 * boost idle prio on transactions that would lock out other
1816 * users of the filesystem
1818 if (cfq_class_idle(cfqq
))
1819 cfqq
->ioprio_class
= IOPRIO_CLASS_BE
;
1820 if (cfqq
->ioprio
> IOPRIO_NORM
)
1821 cfqq
->ioprio
= IOPRIO_NORM
;
1824 * check if we need to unboost the queue
1826 if (cfqq
->ioprio_class
!= cfqq
->org_ioprio_class
)
1827 cfqq
->ioprio_class
= cfqq
->org_ioprio_class
;
1828 if (cfqq
->ioprio
!= cfqq
->org_ioprio
)
1829 cfqq
->ioprio
= cfqq
->org_ioprio
;
1833 * refile between round-robin lists if we moved the priority class
1835 if ((ioprio_class
!= cfqq
->ioprio_class
|| ioprio
!= cfqq
->ioprio
) &&
1836 cfq_cfqq_on_rr(cfqq
))
1837 cfq_resort_rr_list(cfqq
, 0);
1840 static inline pid_t
cfq_queue_pid(struct task_struct
*task
, int rw
)
1842 if (rw
== READ
|| process_sync(task
))
1845 return CFQ_KEY_ASYNC
;
1849 __cfq_may_queue(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
1850 struct task_struct
*task
, int rw
)
1853 if ((cfq_cfqq_wait_request(cfqq
) || cfq_cfqq_must_alloc(cfqq
)) &&
1854 !cfq_cfqq_must_alloc_slice(cfqq
)) {
1855 cfq_mark_cfqq_must_alloc_slice(cfqq
);
1856 return ELV_MQUEUE_MUST
;
1859 return ELV_MQUEUE_MAY
;
1861 if (!cfqq
|| task
->flags
& PF_MEMALLOC
)
1862 return ELV_MQUEUE_MAY
;
1863 if (!cfqq
->allocated
[rw
] || cfq_cfqq_must_alloc(cfqq
)) {
1864 if (cfq_cfqq_wait_request(cfqq
))
1865 return ELV_MQUEUE_MUST
;
1868 * only allow 1 ELV_MQUEUE_MUST per slice, otherwise we
1869 * can quickly flood the queue with writes from a single task
1871 if (rw
== READ
|| !cfq_cfqq_must_alloc_slice(cfqq
)) {
1872 cfq_mark_cfqq_must_alloc_slice(cfqq
);
1873 return ELV_MQUEUE_MUST
;
1876 return ELV_MQUEUE_MAY
;
1878 if (cfq_class_idle(cfqq
))
1879 return ELV_MQUEUE_NO
;
1880 if (cfqq
->allocated
[rw
] >= cfqd
->max_queued
) {
1881 struct io_context
*ioc
= get_io_context(GFP_ATOMIC
);
1882 int ret
= ELV_MQUEUE_NO
;
1884 if (ioc
&& ioc
->nr_batch_requests
)
1885 ret
= ELV_MQUEUE_MAY
;
1887 put_io_context(ioc
);
1891 return ELV_MQUEUE_MAY
;
1895 static int cfq_may_queue(request_queue_t
*q
, int rw
, struct bio
*bio
)
1897 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
1898 struct task_struct
*tsk
= current
;
1899 struct cfq_queue
*cfqq
;
1902 * don't force setup of a queue from here, as a call to may_queue
1903 * does not necessarily imply that a request actually will be queued.
1904 * so just lookup a possibly existing queue, or return 'may queue'
1907 cfqq
= cfq_find_cfq_hash(cfqd
, cfq_queue_pid(tsk
, rw
), tsk
->ioprio
);
1909 cfq_init_prio_data(cfqq
);
1910 cfq_prio_boost(cfqq
);
1912 return __cfq_may_queue(cfqd
, cfqq
, tsk
, rw
);
1915 return ELV_MQUEUE_MAY
;
1918 static void cfq_check_waiters(request_queue_t
*q
, struct cfq_queue
*cfqq
)
1920 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
1921 struct request_list
*rl
= &q
->rq
;
1923 if (cfqq
->allocated
[READ
] <= cfqd
->max_queued
|| cfqd
->rq_starved
) {
1925 if (waitqueue_active(&rl
->wait
[READ
]))
1926 wake_up(&rl
->wait
[READ
]);
1929 if (cfqq
->allocated
[WRITE
] <= cfqd
->max_queued
|| cfqd
->rq_starved
) {
1931 if (waitqueue_active(&rl
->wait
[WRITE
]))
1932 wake_up(&rl
->wait
[WRITE
]);
1937 * queue lock held here
1939 static void cfq_put_request(request_queue_t
*q
, struct request
*rq
)
1941 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
1942 struct cfq_rq
*crq
= RQ_DATA(rq
);
1945 struct cfq_queue
*cfqq
= crq
->cfq_queue
;
1946 const int rw
= rq_data_dir(rq
);
1948 BUG_ON(!cfqq
->allocated
[rw
]);
1949 cfqq
->allocated
[rw
]--;
1951 put_io_context(crq
->io_context
->ioc
);
1953 mempool_free(crq
, cfqd
->crq_pool
);
1954 rq
->elevator_private
= NULL
;
1956 cfq_check_waiters(q
, cfqq
);
1957 cfq_put_queue(cfqq
);
1962 * Allocate cfq data structures associated with this request.
1965 cfq_set_request(request_queue_t
*q
, struct request
*rq
, struct bio
*bio
,
1968 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
1969 struct task_struct
*tsk
= current
;
1970 struct cfq_io_context
*cic
;
1971 const int rw
= rq_data_dir(rq
);
1972 pid_t key
= cfq_queue_pid(tsk
, rw
);
1973 struct cfq_queue
*cfqq
;
1975 unsigned long flags
;
1976 int is_sync
= key
!= CFQ_KEY_ASYNC
;
1978 might_sleep_if(gfp_mask
& __GFP_WAIT
);
1980 cic
= cfq_get_io_context(cfqd
, key
, gfp_mask
);
1982 spin_lock_irqsave(q
->queue_lock
, flags
);
1987 if (!cic
->cfqq
[is_sync
]) {
1988 cfqq
= cfq_get_queue(cfqd
, key
, tsk
, gfp_mask
);
1992 cic
->cfqq
[is_sync
] = cfqq
;
1994 cfqq
= cic
->cfqq
[is_sync
];
1996 cfqq
->allocated
[rw
]++;
1997 cfq_clear_cfqq_must_alloc(cfqq
);
1998 cfqd
->rq_starved
= 0;
1999 atomic_inc(&cfqq
->ref
);
2000 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2002 crq
= mempool_alloc(cfqd
->crq_pool
, gfp_mask
);
2004 RB_CLEAR(&crq
->rb_node
);
2007 INIT_HLIST_NODE(&crq
->hash
);
2008 crq
->cfq_queue
= cfqq
;
2009 crq
->io_context
= cic
;
2012 cfq_mark_crq_is_sync(crq
);
2014 cfq_clear_crq_is_sync(crq
);
2016 rq
->elevator_private
= crq
;
2020 spin_lock_irqsave(q
->queue_lock
, flags
);
2021 cfqq
->allocated
[rw
]--;
2022 if (!(cfqq
->allocated
[0] + cfqq
->allocated
[1]))
2023 cfq_mark_cfqq_must_alloc(cfqq
);
2024 cfq_put_queue(cfqq
);
2027 put_io_context(cic
->ioc
);
2029 * mark us rq allocation starved. we need to kickstart the process
2030 * ourselves if there are no pending requests that can do it for us.
2031 * that would be an extremely rare OOM situation
2033 cfqd
->rq_starved
= 1;
2034 cfq_schedule_dispatch(cfqd
);
2035 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2039 static void cfq_kick_queue(void *data
)
2041 request_queue_t
*q
= data
;
2042 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
2043 unsigned long flags
;
2045 spin_lock_irqsave(q
->queue_lock
, flags
);
2047 if (cfqd
->rq_starved
) {
2048 struct request_list
*rl
= &q
->rq
;
2051 * we aren't guaranteed to get a request after this, but we
2052 * have to be opportunistic
2055 if (waitqueue_active(&rl
->wait
[READ
]))
2056 wake_up(&rl
->wait
[READ
]);
2057 if (waitqueue_active(&rl
->wait
[WRITE
]))
2058 wake_up(&rl
->wait
[WRITE
]);
2063 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2067 * Timer running if the active_queue is currently idling inside its time slice
2069 static void cfq_idle_slice_timer(unsigned long data
)
2071 struct cfq_data
*cfqd
= (struct cfq_data
*) data
;
2072 struct cfq_queue
*cfqq
;
2073 unsigned long flags
;
2075 spin_lock_irqsave(cfqd
->queue
->queue_lock
, flags
);
2077 if ((cfqq
= cfqd
->active_queue
) != NULL
) {
2078 unsigned long now
= jiffies
;
2083 if (time_after(now
, cfqq
->slice_end
))
2087 * only expire and reinvoke request handler, if there are
2088 * other queues with pending requests
2090 if (!cfqd
->busy_queues
) {
2091 cfqd
->idle_slice_timer
.expires
= min(now
+ cfqd
->cfq_slice_idle
, cfqq
->slice_end
);
2092 add_timer(&cfqd
->idle_slice_timer
);
2097 * not expired and it has a request pending, let it dispatch
2099 if (!RB_EMPTY(&cfqq
->sort_list
)) {
2100 cfq_mark_cfqq_must_dispatch(cfqq
);
2105 cfq_slice_expired(cfqd
, 0);
2107 cfq_schedule_dispatch(cfqd
);
2109 spin_unlock_irqrestore(cfqd
->queue
->queue_lock
, flags
);
2113 * Timer running if an idle class queue is waiting for service
2115 static void cfq_idle_class_timer(unsigned long data
)
2117 struct cfq_data
*cfqd
= (struct cfq_data
*) data
;
2118 unsigned long flags
, end
;
2120 spin_lock_irqsave(cfqd
->queue
->queue_lock
, flags
);
2123 * race with a non-idle queue, reset timer
2125 end
= cfqd
->last_end_request
+ CFQ_IDLE_GRACE
;
2126 if (!time_after_eq(jiffies
, end
)) {
2127 cfqd
->idle_class_timer
.expires
= end
;
2128 add_timer(&cfqd
->idle_class_timer
);
2130 cfq_schedule_dispatch(cfqd
);
2132 spin_unlock_irqrestore(cfqd
->queue
->queue_lock
, flags
);
2135 static void cfq_shutdown_timer_wq(struct cfq_data
*cfqd
)
2137 del_timer_sync(&cfqd
->idle_slice_timer
);
2138 del_timer_sync(&cfqd
->idle_class_timer
);
2139 blk_sync_queue(cfqd
->queue
);
2142 static void cfq_exit_queue(elevator_t
*e
)
2144 struct cfq_data
*cfqd
= e
->elevator_data
;
2145 request_queue_t
*q
= cfqd
->queue
;
2147 cfq_shutdown_timer_wq(cfqd
);
2148 write_lock(&cfq_exit_lock
);
2149 spin_lock_irq(q
->queue_lock
);
2150 if (cfqd
->active_queue
)
2151 __cfq_slice_expired(cfqd
, cfqd
->active_queue
, 0);
2152 while(!list_empty(&cfqd
->cic_list
)) {
2153 struct cfq_io_context
*cic
= list_entry(cfqd
->cic_list
.next
,
2154 struct cfq_io_context
,
2156 if (cic
->cfqq
[ASYNC
]) {
2157 cfq_put_queue(cic
->cfqq
[ASYNC
]);
2158 cic
->cfqq
[ASYNC
] = NULL
;
2160 if (cic
->cfqq
[SYNC
]) {
2161 cfq_put_queue(cic
->cfqq
[SYNC
]);
2162 cic
->cfqq
[SYNC
] = NULL
;
2165 list_del_init(&cic
->queue_list
);
2167 spin_unlock_irq(q
->queue_lock
);
2168 write_unlock(&cfq_exit_lock
);
2170 cfq_shutdown_timer_wq(cfqd
);
2172 mempool_destroy(cfqd
->crq_pool
);
2173 kfree(cfqd
->crq_hash
);
2174 kfree(cfqd
->cfq_hash
);
2178 static int cfq_init_queue(request_queue_t
*q
, elevator_t
*e
)
2180 struct cfq_data
*cfqd
;
2183 cfqd
= kmalloc(sizeof(*cfqd
), GFP_KERNEL
);
2187 memset(cfqd
, 0, sizeof(*cfqd
));
2189 for (i
= 0; i
< CFQ_PRIO_LISTS
; i
++)
2190 INIT_LIST_HEAD(&cfqd
->rr_list
[i
]);
2192 INIT_LIST_HEAD(&cfqd
->busy_rr
);
2193 INIT_LIST_HEAD(&cfqd
->cur_rr
);
2194 INIT_LIST_HEAD(&cfqd
->idle_rr
);
2195 INIT_LIST_HEAD(&cfqd
->empty_list
);
2196 INIT_LIST_HEAD(&cfqd
->cic_list
);
2198 cfqd
->crq_hash
= kmalloc(sizeof(struct hlist_head
) * CFQ_MHASH_ENTRIES
, GFP_KERNEL
);
2199 if (!cfqd
->crq_hash
)
2202 cfqd
->cfq_hash
= kmalloc(sizeof(struct hlist_head
) * CFQ_QHASH_ENTRIES
, GFP_KERNEL
);
2203 if (!cfqd
->cfq_hash
)
2206 cfqd
->crq_pool
= mempool_create(BLKDEV_MIN_RQ
, mempool_alloc_slab
, mempool_free_slab
, crq_pool
);
2207 if (!cfqd
->crq_pool
)
2210 for (i
= 0; i
< CFQ_MHASH_ENTRIES
; i
++)
2211 INIT_HLIST_HEAD(&cfqd
->crq_hash
[i
]);
2212 for (i
= 0; i
< CFQ_QHASH_ENTRIES
; i
++)
2213 INIT_HLIST_HEAD(&cfqd
->cfq_hash
[i
]);
2215 e
->elevator_data
= cfqd
;
2219 cfqd
->max_queued
= q
->nr_requests
/ 4;
2220 q
->nr_batching
= cfq_queued
;
2222 init_timer(&cfqd
->idle_slice_timer
);
2223 cfqd
->idle_slice_timer
.function
= cfq_idle_slice_timer
;
2224 cfqd
->idle_slice_timer
.data
= (unsigned long) cfqd
;
2226 init_timer(&cfqd
->idle_class_timer
);
2227 cfqd
->idle_class_timer
.function
= cfq_idle_class_timer
;
2228 cfqd
->idle_class_timer
.data
= (unsigned long) cfqd
;
2230 INIT_WORK(&cfqd
->unplug_work
, cfq_kick_queue
, q
);
2232 cfqd
->cfq_queued
= cfq_queued
;
2233 cfqd
->cfq_quantum
= cfq_quantum
;
2234 cfqd
->cfq_fifo_expire
[0] = cfq_fifo_expire
[0];
2235 cfqd
->cfq_fifo_expire
[1] = cfq_fifo_expire
[1];
2236 cfqd
->cfq_back_max
= cfq_back_max
;
2237 cfqd
->cfq_back_penalty
= cfq_back_penalty
;
2238 cfqd
->cfq_slice
[0] = cfq_slice_async
;
2239 cfqd
->cfq_slice
[1] = cfq_slice_sync
;
2240 cfqd
->cfq_slice_async_rq
= cfq_slice_async_rq
;
2241 cfqd
->cfq_slice_idle
= cfq_slice_idle
;
2242 cfqd
->cfq_max_depth
= cfq_max_depth
;
2246 kfree(cfqd
->cfq_hash
);
2248 kfree(cfqd
->crq_hash
);
2254 static void cfq_slab_kill(void)
2257 kmem_cache_destroy(crq_pool
);
2259 kmem_cache_destroy(cfq_pool
);
2261 kmem_cache_destroy(cfq_ioc_pool
);
2264 static int __init
cfq_slab_setup(void)
2266 crq_pool
= kmem_cache_create("crq_pool", sizeof(struct cfq_rq
), 0, 0,
2271 cfq_pool
= kmem_cache_create("cfq_pool", sizeof(struct cfq_queue
), 0, 0,
2276 cfq_ioc_pool
= kmem_cache_create("cfq_ioc_pool",
2277 sizeof(struct cfq_io_context
), 0, 0, NULL
, NULL
);
2288 * sysfs parts below -->
2290 struct cfq_fs_entry
{
2291 struct attribute attr
;
2292 ssize_t (*show
)(struct cfq_data
*, char *);
2293 ssize_t (*store
)(struct cfq_data
*, const char *, size_t);
2297 cfq_var_show(unsigned int var
, char *page
)
2299 return sprintf(page
, "%d\n", var
);
2303 cfq_var_store(unsigned int *var
, const char *page
, size_t count
)
2305 char *p
= (char *) page
;
2307 *var
= simple_strtoul(p
, &p
, 10);
2311 #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \
2312 static ssize_t __FUNC(struct cfq_data *cfqd, char *page) \
2314 unsigned int __data = __VAR; \
2316 __data = jiffies_to_msecs(__data); \
2317 return cfq_var_show(__data, (page)); \
2319 SHOW_FUNCTION(cfq_quantum_show
, cfqd
->cfq_quantum
, 0);
2320 SHOW_FUNCTION(cfq_queued_show
, cfqd
->cfq_queued
, 0);
2321 SHOW_FUNCTION(cfq_fifo_expire_sync_show
, cfqd
->cfq_fifo_expire
[1], 1);
2322 SHOW_FUNCTION(cfq_fifo_expire_async_show
, cfqd
->cfq_fifo_expire
[0], 1);
2323 SHOW_FUNCTION(cfq_back_max_show
, cfqd
->cfq_back_max
, 0);
2324 SHOW_FUNCTION(cfq_back_penalty_show
, cfqd
->cfq_back_penalty
, 0);
2325 SHOW_FUNCTION(cfq_slice_idle_show
, cfqd
->cfq_slice_idle
, 1);
2326 SHOW_FUNCTION(cfq_slice_sync_show
, cfqd
->cfq_slice
[1], 1);
2327 SHOW_FUNCTION(cfq_slice_async_show
, cfqd
->cfq_slice
[0], 1);
2328 SHOW_FUNCTION(cfq_slice_async_rq_show
, cfqd
->cfq_slice_async_rq
, 0);
2329 SHOW_FUNCTION(cfq_max_depth_show
, cfqd
->cfq_max_depth
, 0);
2330 #undef SHOW_FUNCTION
2332 #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \
2333 static ssize_t __FUNC(struct cfq_data *cfqd, const char *page, size_t count) \
2335 unsigned int __data; \
2336 int ret = cfq_var_store(&__data, (page), count); \
2337 if (__data < (MIN)) \
2339 else if (__data > (MAX)) \
2342 *(__PTR) = msecs_to_jiffies(__data); \
2344 *(__PTR) = __data; \
2347 STORE_FUNCTION(cfq_quantum_store
, &cfqd
->cfq_quantum
, 1, UINT_MAX
, 0);
2348 STORE_FUNCTION(cfq_queued_store
, &cfqd
->cfq_queued
, 1, UINT_MAX
, 0);
2349 STORE_FUNCTION(cfq_fifo_expire_sync_store
, &cfqd
->cfq_fifo_expire
[1], 1, UINT_MAX
, 1);
2350 STORE_FUNCTION(cfq_fifo_expire_async_store
, &cfqd
->cfq_fifo_expire
[0], 1, UINT_MAX
, 1);
2351 STORE_FUNCTION(cfq_back_max_store
, &cfqd
->cfq_back_max
, 0, UINT_MAX
, 0);
2352 STORE_FUNCTION(cfq_back_penalty_store
, &cfqd
->cfq_back_penalty
, 1, UINT_MAX
, 0);
2353 STORE_FUNCTION(cfq_slice_idle_store
, &cfqd
->cfq_slice_idle
, 0, UINT_MAX
, 1);
2354 STORE_FUNCTION(cfq_slice_sync_store
, &cfqd
->cfq_slice
[1], 1, UINT_MAX
, 1);
2355 STORE_FUNCTION(cfq_slice_async_store
, &cfqd
->cfq_slice
[0], 1, UINT_MAX
, 1);
2356 STORE_FUNCTION(cfq_slice_async_rq_store
, &cfqd
->cfq_slice_async_rq
, 1, UINT_MAX
, 0);
2357 STORE_FUNCTION(cfq_max_depth_store
, &cfqd
->cfq_max_depth
, 1, UINT_MAX
, 0);
2358 #undef STORE_FUNCTION
2360 static struct cfq_fs_entry cfq_quantum_entry
= {
2361 .attr
= {.name
= "quantum", .mode
= S_IRUGO
| S_IWUSR
},
2362 .show
= cfq_quantum_show
,
2363 .store
= cfq_quantum_store
,
2365 static struct cfq_fs_entry cfq_queued_entry
= {
2366 .attr
= {.name
= "queued", .mode
= S_IRUGO
| S_IWUSR
},
2367 .show
= cfq_queued_show
,
2368 .store
= cfq_queued_store
,
2370 static struct cfq_fs_entry cfq_fifo_expire_sync_entry
= {
2371 .attr
= {.name
= "fifo_expire_sync", .mode
= S_IRUGO
| S_IWUSR
},
2372 .show
= cfq_fifo_expire_sync_show
,
2373 .store
= cfq_fifo_expire_sync_store
,
2375 static struct cfq_fs_entry cfq_fifo_expire_async_entry
= {
2376 .attr
= {.name
= "fifo_expire_async", .mode
= S_IRUGO
| S_IWUSR
},
2377 .show
= cfq_fifo_expire_async_show
,
2378 .store
= cfq_fifo_expire_async_store
,
2380 static struct cfq_fs_entry cfq_back_max_entry
= {
2381 .attr
= {.name
= "back_seek_max", .mode
= S_IRUGO
| S_IWUSR
},
2382 .show
= cfq_back_max_show
,
2383 .store
= cfq_back_max_store
,
2385 static struct cfq_fs_entry cfq_back_penalty_entry
= {
2386 .attr
= {.name
= "back_seek_penalty", .mode
= S_IRUGO
| S_IWUSR
},
2387 .show
= cfq_back_penalty_show
,
2388 .store
= cfq_back_penalty_store
,
2390 static struct cfq_fs_entry cfq_slice_sync_entry
= {
2391 .attr
= {.name
= "slice_sync", .mode
= S_IRUGO
| S_IWUSR
},
2392 .show
= cfq_slice_sync_show
,
2393 .store
= cfq_slice_sync_store
,
2395 static struct cfq_fs_entry cfq_slice_async_entry
= {
2396 .attr
= {.name
= "slice_async", .mode
= S_IRUGO
| S_IWUSR
},
2397 .show
= cfq_slice_async_show
,
2398 .store
= cfq_slice_async_store
,
2400 static struct cfq_fs_entry cfq_slice_async_rq_entry
= {
2401 .attr
= {.name
= "slice_async_rq", .mode
= S_IRUGO
| S_IWUSR
},
2402 .show
= cfq_slice_async_rq_show
,
2403 .store
= cfq_slice_async_rq_store
,
2405 static struct cfq_fs_entry cfq_slice_idle_entry
= {
2406 .attr
= {.name
= "slice_idle", .mode
= S_IRUGO
| S_IWUSR
},
2407 .show
= cfq_slice_idle_show
,
2408 .store
= cfq_slice_idle_store
,
2410 static struct cfq_fs_entry cfq_max_depth_entry
= {
2411 .attr
= {.name
= "max_depth", .mode
= S_IRUGO
| S_IWUSR
},
2412 .show
= cfq_max_depth_show
,
2413 .store
= cfq_max_depth_store
,
2416 static struct attribute
*default_attrs
[] = {
2417 &cfq_quantum_entry
.attr
,
2418 &cfq_queued_entry
.attr
,
2419 &cfq_fifo_expire_sync_entry
.attr
,
2420 &cfq_fifo_expire_async_entry
.attr
,
2421 &cfq_back_max_entry
.attr
,
2422 &cfq_back_penalty_entry
.attr
,
2423 &cfq_slice_sync_entry
.attr
,
2424 &cfq_slice_async_entry
.attr
,
2425 &cfq_slice_async_rq_entry
.attr
,
2426 &cfq_slice_idle_entry
.attr
,
2427 &cfq_max_depth_entry
.attr
,
2431 #define to_cfq(atr) container_of((atr), struct cfq_fs_entry, attr)
2434 cfq_attr_show(struct kobject
*kobj
, struct attribute
*attr
, char *page
)
2436 elevator_t
*e
= container_of(kobj
, elevator_t
, kobj
);
2437 struct cfq_fs_entry
*entry
= to_cfq(attr
);
2442 return entry
->show(e
->elevator_data
, page
);
2446 cfq_attr_store(struct kobject
*kobj
, struct attribute
*attr
,
2447 const char *page
, size_t length
)
2449 elevator_t
*e
= container_of(kobj
, elevator_t
, kobj
);
2450 struct cfq_fs_entry
*entry
= to_cfq(attr
);
2455 return entry
->store(e
->elevator_data
, page
, length
);
2458 static struct sysfs_ops cfq_sysfs_ops
= {
2459 .show
= cfq_attr_show
,
2460 .store
= cfq_attr_store
,
2463 static struct kobj_type cfq_ktype
= {
2464 .sysfs_ops
= &cfq_sysfs_ops
,
2465 .default_attrs
= default_attrs
,
2468 static struct elevator_type iosched_cfq
= {
2470 .elevator_merge_fn
= cfq_merge
,
2471 .elevator_merged_fn
= cfq_merged_request
,
2472 .elevator_merge_req_fn
= cfq_merged_requests
,
2473 .elevator_dispatch_fn
= cfq_dispatch_requests
,
2474 .elevator_add_req_fn
= cfq_insert_request
,
2475 .elevator_activate_req_fn
= cfq_activate_request
,
2476 .elevator_deactivate_req_fn
= cfq_deactivate_request
,
2477 .elevator_queue_empty_fn
= cfq_queue_empty
,
2478 .elevator_completed_req_fn
= cfq_completed_request
,
2479 .elevator_former_req_fn
= cfq_former_request
,
2480 .elevator_latter_req_fn
= cfq_latter_request
,
2481 .elevator_set_req_fn
= cfq_set_request
,
2482 .elevator_put_req_fn
= cfq_put_request
,
2483 .elevator_may_queue_fn
= cfq_may_queue
,
2484 .elevator_init_fn
= cfq_init_queue
,
2485 .elevator_exit_fn
= cfq_exit_queue
,
2488 .elevator_ktype
= &cfq_ktype
,
2489 .elevator_name
= "cfq",
2490 .elevator_owner
= THIS_MODULE
,
2493 static int __init
cfq_init(void)
2498 * could be 0 on HZ < 1000 setups
2500 if (!cfq_slice_async
)
2501 cfq_slice_async
= 1;
2502 if (!cfq_slice_idle
)
2505 if (cfq_slab_setup())
2508 ret
= elv_register(&iosched_cfq
);
2515 static void __exit
cfq_exit(void)
2517 DECLARE_COMPLETION(all_gone
);
2518 elv_unregister(&iosched_cfq
);
2519 ioc_gone
= &all_gone
;
2521 if (atomic_read(&ioc_count
))
2527 module_init(cfq_init
);
2528 module_exit(cfq_exit
);
2530 MODULE_AUTHOR("Jens Axboe");
2531 MODULE_LICENSE("GPL");
2532 MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler");