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
/ 70;
31 #define CFQ_IDLE_GRACE (HZ / 10)
32 #define CFQ_SLICE_SCALE (5)
34 #define CFQ_KEY_ASYNC (0)
36 static DEFINE_SPINLOCK(cfq_exit_lock
);
39 * for the hash of cfqq inside the cfqd
41 #define CFQ_QHASH_SHIFT 6
42 #define CFQ_QHASH_ENTRIES (1 << CFQ_QHASH_SHIFT)
43 #define list_entry_qhash(entry) hlist_entry((entry), struct cfq_queue, cfq_hash)
46 * for the hash of crq inside the cfqq
48 #define CFQ_MHASH_SHIFT 6
49 #define CFQ_MHASH_BLOCK(sec) ((sec) >> 3)
50 #define CFQ_MHASH_ENTRIES (1 << CFQ_MHASH_SHIFT)
51 #define CFQ_MHASH_FN(sec) hash_long(CFQ_MHASH_BLOCK(sec), CFQ_MHASH_SHIFT)
52 #define rq_hash_key(rq) ((rq)->sector + (rq)->nr_sectors)
53 #define list_entry_hash(ptr) hlist_entry((ptr), struct cfq_rq, hash)
55 #define list_entry_cfqq(ptr) list_entry((ptr), struct cfq_queue, cfq_list)
56 #define list_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
58 #define RQ_DATA(rq) (rq)->elevator_private
64 #define RB_EMPTY(node) ((node)->rb_node == NULL)
65 #define RB_CLEAR_COLOR(node) (node)->rb_color = RB_NONE
66 #define RB_CLEAR(node) do { \
67 (node)->rb_parent = NULL; \
68 RB_CLEAR_COLOR((node)); \
69 (node)->rb_right = NULL; \
70 (node)->rb_left = NULL; \
72 #define RB_CLEAR_ROOT(root) ((root)->rb_node = NULL)
73 #define rb_entry_crq(node) rb_entry((node), struct cfq_rq, rb_node)
74 #define rq_rb_key(rq) (rq)->sector
76 static kmem_cache_t
*crq_pool
;
77 static kmem_cache_t
*cfq_pool
;
78 static kmem_cache_t
*cfq_ioc_pool
;
80 static atomic_t ioc_count
= ATOMIC_INIT(0);
81 static struct completion
*ioc_gone
;
83 #define CFQ_PRIO_LISTS IOPRIO_BE_NR
84 #define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE)
85 #define cfq_class_be(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_BE)
86 #define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT)
91 #define cfq_cfqq_dispatched(cfqq) \
92 ((cfqq)->on_dispatch[ASYNC] + (cfqq)->on_dispatch[SYNC])
94 #define cfq_cfqq_class_sync(cfqq) ((cfqq)->key != CFQ_KEY_ASYNC)
96 #define cfq_cfqq_sync(cfqq) \
97 (cfq_cfqq_class_sync(cfqq) || (cfqq)->on_dispatch[SYNC])
99 #define sample_valid(samples) ((samples) > 80)
102 * Per block device queue structure
105 request_queue_t
*queue
;
108 * rr list of queues with requests and the count of them
110 struct list_head rr_list
[CFQ_PRIO_LISTS
];
111 struct list_head busy_rr
;
112 struct list_head cur_rr
;
113 struct list_head idle_rr
;
114 unsigned int busy_queues
;
117 * non-ordered list of empty cfqq's
119 struct list_head empty_list
;
124 struct hlist_head
*cfq_hash
;
127 * global crq hash for all queues
129 struct hlist_head
*crq_hash
;
131 unsigned int max_queued
;
139 * schedule slice state info
142 * idle window management
144 struct timer_list idle_slice_timer
;
145 struct work_struct unplug_work
;
147 struct cfq_queue
*active_queue
;
148 struct cfq_io_context
*active_cic
;
149 int cur_prio
, cur_end_prio
;
150 unsigned int dispatch_slice
;
152 struct timer_list idle_class_timer
;
154 sector_t last_sector
;
155 unsigned long last_end_request
;
157 unsigned int rq_starved
;
160 * tunables, see top of file
162 unsigned int cfq_quantum
;
163 unsigned int cfq_queued
;
164 unsigned int cfq_fifo_expire
[2];
165 unsigned int cfq_back_penalty
;
166 unsigned int cfq_back_max
;
167 unsigned int cfq_slice
[2];
168 unsigned int cfq_slice_async_rq
;
169 unsigned int cfq_slice_idle
;
171 struct list_head cic_list
;
175 * Per process-grouping structure
178 /* reference count */
180 /* parent cfq_data */
181 struct cfq_data
*cfqd
;
182 /* cfqq lookup hash */
183 struct hlist_node cfq_hash
;
186 /* on either rr or empty list of cfqd */
187 struct list_head cfq_list
;
188 /* sorted list of pending requests */
189 struct rb_root sort_list
;
190 /* if fifo isn't expired, next request to serve */
191 struct cfq_rq
*next_crq
;
192 /* requests queued in sort_list */
194 /* currently allocated requests */
196 /* fifo list of requests in sort_list */
197 struct list_head fifo
;
199 unsigned long slice_start
;
200 unsigned long slice_end
;
201 unsigned long slice_left
;
202 unsigned long service_last
;
204 /* number of requests that are on the dispatch list */
207 /* io prio of this group */
208 unsigned short ioprio
, org_ioprio
;
209 unsigned short ioprio_class
, org_ioprio_class
;
211 /* various state flags, see below */
216 struct rb_node rb_node
;
218 struct request
*request
;
219 struct hlist_node hash
;
221 struct cfq_queue
*cfq_queue
;
222 struct cfq_io_context
*io_context
;
224 unsigned int crq_flags
;
227 enum cfqq_state_flags
{
228 CFQ_CFQQ_FLAG_on_rr
= 0,
229 CFQ_CFQQ_FLAG_wait_request
,
230 CFQ_CFQQ_FLAG_must_alloc
,
231 CFQ_CFQQ_FLAG_must_alloc_slice
,
232 CFQ_CFQQ_FLAG_must_dispatch
,
233 CFQ_CFQQ_FLAG_fifo_expire
,
234 CFQ_CFQQ_FLAG_idle_window
,
235 CFQ_CFQQ_FLAG_prio_changed
,
238 #define CFQ_CFQQ_FNS(name) \
239 static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \
241 cfqq->flags |= (1 << CFQ_CFQQ_FLAG_##name); \
243 static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \
245 cfqq->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \
247 static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \
249 return (cfqq->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \
253 CFQ_CFQQ_FNS(wait_request
);
254 CFQ_CFQQ_FNS(must_alloc
);
255 CFQ_CFQQ_FNS(must_alloc_slice
);
256 CFQ_CFQQ_FNS(must_dispatch
);
257 CFQ_CFQQ_FNS(fifo_expire
);
258 CFQ_CFQQ_FNS(idle_window
);
259 CFQ_CFQQ_FNS(prio_changed
);
262 enum cfq_rq_state_flags
{
263 CFQ_CRQ_FLAG_is_sync
= 0,
266 #define CFQ_CRQ_FNS(name) \
267 static inline void cfq_mark_crq_##name(struct cfq_rq *crq) \
269 crq->crq_flags |= (1 << CFQ_CRQ_FLAG_##name); \
271 static inline void cfq_clear_crq_##name(struct cfq_rq *crq) \
273 crq->crq_flags &= ~(1 << CFQ_CRQ_FLAG_##name); \
275 static inline int cfq_crq_##name(const struct cfq_rq *crq) \
277 return (crq->crq_flags & (1 << CFQ_CRQ_FLAG_##name)) != 0; \
280 CFQ_CRQ_FNS(is_sync
);
283 static struct cfq_queue
*cfq_find_cfq_hash(struct cfq_data
*, unsigned int, unsigned short);
284 static void cfq_dispatch_insert(request_queue_t
*, struct cfq_rq
*);
285 static struct cfq_queue
*cfq_get_queue(struct cfq_data
*cfqd
, unsigned int key
, struct task_struct
*tsk
, gfp_t gfp_mask
);
287 #define process_sync(tsk) ((tsk)->flags & PF_SYNCWRITE)
290 * lots of deadline iosched dupes, can be abstracted later...
292 static inline void cfq_del_crq_hash(struct cfq_rq
*crq
)
294 hlist_del_init(&crq
->hash
);
297 static inline void cfq_add_crq_hash(struct cfq_data
*cfqd
, struct cfq_rq
*crq
)
299 const int hash_idx
= CFQ_MHASH_FN(rq_hash_key(crq
->request
));
301 hlist_add_head(&crq
->hash
, &cfqd
->crq_hash
[hash_idx
]);
304 static struct request
*cfq_find_rq_hash(struct cfq_data
*cfqd
, sector_t offset
)
306 struct hlist_head
*hash_list
= &cfqd
->crq_hash
[CFQ_MHASH_FN(offset
)];
307 struct hlist_node
*entry
, *next
;
309 hlist_for_each_safe(entry
, next
, hash_list
) {
310 struct cfq_rq
*crq
= list_entry_hash(entry
);
311 struct request
*__rq
= crq
->request
;
313 if (!rq_mergeable(__rq
)) {
314 cfq_del_crq_hash(crq
);
318 if (rq_hash_key(__rq
) == offset
)
326 * scheduler run of queue, if there are requests pending and no one in the
327 * driver that will restart queueing
329 static inline void cfq_schedule_dispatch(struct cfq_data
*cfqd
)
331 if (cfqd
->busy_queues
)
332 kblockd_schedule_work(&cfqd
->unplug_work
);
335 static int cfq_queue_empty(request_queue_t
*q
)
337 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
339 return !cfqd
->busy_queues
;
342 static inline pid_t
cfq_queue_pid(struct task_struct
*task
, int rw
)
344 if (rw
== READ
|| process_sync(task
))
347 return CFQ_KEY_ASYNC
;
351 * Lifted from AS - choose which of crq1 and crq2 that is best served now.
352 * We choose the request that is closest to the head right now. Distance
353 * behind the head is penalized and only allowed to a certain extent.
355 static struct cfq_rq
*
356 cfq_choose_req(struct cfq_data
*cfqd
, struct cfq_rq
*crq1
, struct cfq_rq
*crq2
)
358 sector_t last
, s1
, s2
, d1
= 0, d2
= 0;
359 unsigned long back_max
;
360 #define CFQ_RQ1_WRAP 0x01 /* request 1 wraps */
361 #define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */
362 unsigned wrap
= 0; /* bit mask: requests behind the disk head? */
364 if (crq1
== NULL
|| crq1
== crq2
)
369 if (cfq_crq_is_sync(crq1
) && !cfq_crq_is_sync(crq2
))
371 else if (cfq_crq_is_sync(crq2
) && !cfq_crq_is_sync(crq1
))
374 s1
= crq1
->request
->sector
;
375 s2
= crq2
->request
->sector
;
377 last
= cfqd
->last_sector
;
380 * by definition, 1KiB is 2 sectors
382 back_max
= cfqd
->cfq_back_max
* 2;
385 * Strict one way elevator _except_ in the case where we allow
386 * short backward seeks which are biased as twice the cost of a
387 * similar forward seek.
391 else if (s1
+ back_max
>= last
)
392 d1
= (last
- s1
) * cfqd
->cfq_back_penalty
;
394 wrap
|= CFQ_RQ1_WRAP
;
398 else if (s2
+ back_max
>= last
)
399 d2
= (last
- s2
) * cfqd
->cfq_back_penalty
;
401 wrap
|= CFQ_RQ2_WRAP
;
403 /* Found required data */
406 * By doing switch() on the bit mask "wrap" we avoid having to
407 * check two variables for all permutations: --> faster!
410 case 0: /* common case for CFQ: crq1 and crq2 not wrapped */
426 case (CFQ_RQ1_WRAP
|CFQ_RQ2_WRAP
): /* both crqs wrapped */
429 * Since both rqs are wrapped,
430 * start with the one that's further behind head
431 * (--> only *one* back seek required),
432 * since back seek takes more time than forward.
442 * would be nice to take fifo expire time into account as well
444 static struct cfq_rq
*
445 cfq_find_next_crq(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
448 struct cfq_rq
*crq_next
= NULL
, *crq_prev
= NULL
;
449 struct rb_node
*rbnext
, *rbprev
;
451 if (!(rbnext
= rb_next(&last
->rb_node
))) {
452 rbnext
= rb_first(&cfqq
->sort_list
);
453 if (rbnext
== &last
->rb_node
)
457 rbprev
= rb_prev(&last
->rb_node
);
460 crq_prev
= rb_entry_crq(rbprev
);
462 crq_next
= rb_entry_crq(rbnext
);
464 return cfq_choose_req(cfqd
, crq_next
, crq_prev
);
467 static void cfq_update_next_crq(struct cfq_rq
*crq
)
469 struct cfq_queue
*cfqq
= crq
->cfq_queue
;
471 if (cfqq
->next_crq
== crq
)
472 cfqq
->next_crq
= cfq_find_next_crq(cfqq
->cfqd
, cfqq
, crq
);
475 static void cfq_resort_rr_list(struct cfq_queue
*cfqq
, int preempted
)
477 struct cfq_data
*cfqd
= cfqq
->cfqd
;
478 struct list_head
*list
, *entry
;
480 BUG_ON(!cfq_cfqq_on_rr(cfqq
));
482 list_del(&cfqq
->cfq_list
);
484 if (cfq_class_rt(cfqq
))
485 list
= &cfqd
->cur_rr
;
486 else if (cfq_class_idle(cfqq
))
487 list
= &cfqd
->idle_rr
;
490 * if cfqq has requests in flight, don't allow it to be
491 * found in cfq_set_active_queue before it has finished them.
492 * this is done to increase fairness between a process that
493 * has lots of io pending vs one that only generates one
494 * sporadically or synchronously
496 if (cfq_cfqq_dispatched(cfqq
))
497 list
= &cfqd
->busy_rr
;
499 list
= &cfqd
->rr_list
[cfqq
->ioprio
];
503 * if queue was preempted, just add to front to be fair. busy_rr
506 if (preempted
|| list
== &cfqd
->busy_rr
) {
507 list_add(&cfqq
->cfq_list
, list
);
512 * sort by when queue was last serviced
515 while ((entry
= entry
->prev
) != list
) {
516 struct cfq_queue
*__cfqq
= list_entry_cfqq(entry
);
518 if (!__cfqq
->service_last
)
520 if (time_before(__cfqq
->service_last
, cfqq
->service_last
))
524 list_add(&cfqq
->cfq_list
, entry
);
528 * add to busy list of queues for service, trying to be fair in ordering
529 * the pending list according to last request service
532 cfq_add_cfqq_rr(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
534 BUG_ON(cfq_cfqq_on_rr(cfqq
));
535 cfq_mark_cfqq_on_rr(cfqq
);
538 cfq_resort_rr_list(cfqq
, 0);
542 cfq_del_cfqq_rr(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
544 BUG_ON(!cfq_cfqq_on_rr(cfqq
));
545 cfq_clear_cfqq_on_rr(cfqq
);
546 list_move(&cfqq
->cfq_list
, &cfqd
->empty_list
);
548 BUG_ON(!cfqd
->busy_queues
);
553 * rb tree support functions
555 static inline void cfq_del_crq_rb(struct cfq_rq
*crq
)
557 struct cfq_queue
*cfqq
= crq
->cfq_queue
;
558 struct cfq_data
*cfqd
= cfqq
->cfqd
;
559 const int sync
= cfq_crq_is_sync(crq
);
561 BUG_ON(!cfqq
->queued
[sync
]);
562 cfqq
->queued
[sync
]--;
564 cfq_update_next_crq(crq
);
566 rb_erase(&crq
->rb_node
, &cfqq
->sort_list
);
567 RB_CLEAR_COLOR(&crq
->rb_node
);
569 if (cfq_cfqq_on_rr(cfqq
) && RB_EMPTY(&cfqq
->sort_list
))
570 cfq_del_cfqq_rr(cfqd
, cfqq
);
573 static struct cfq_rq
*
574 __cfq_add_crq_rb(struct cfq_rq
*crq
)
576 struct rb_node
**p
= &crq
->cfq_queue
->sort_list
.rb_node
;
577 struct rb_node
*parent
= NULL
;
578 struct cfq_rq
*__crq
;
582 __crq
= rb_entry_crq(parent
);
584 if (crq
->rb_key
< __crq
->rb_key
)
586 else if (crq
->rb_key
> __crq
->rb_key
)
592 rb_link_node(&crq
->rb_node
, parent
, p
);
596 static void cfq_add_crq_rb(struct cfq_rq
*crq
)
598 struct cfq_queue
*cfqq
= crq
->cfq_queue
;
599 struct cfq_data
*cfqd
= cfqq
->cfqd
;
600 struct request
*rq
= crq
->request
;
601 struct cfq_rq
*__alias
;
603 crq
->rb_key
= rq_rb_key(rq
);
604 cfqq
->queued
[cfq_crq_is_sync(crq
)]++;
607 * looks a little odd, but the first insert might return an alias.
608 * if that happens, put the alias on the dispatch list
610 while ((__alias
= __cfq_add_crq_rb(crq
)) != NULL
)
611 cfq_dispatch_insert(cfqd
->queue
, __alias
);
613 rb_insert_color(&crq
->rb_node
, &cfqq
->sort_list
);
615 if (!cfq_cfqq_on_rr(cfqq
))
616 cfq_add_cfqq_rr(cfqd
, cfqq
);
619 * check if this request is a better next-serve candidate
621 cfqq
->next_crq
= cfq_choose_req(cfqd
, cfqq
->next_crq
, crq
);
625 cfq_reposition_crq_rb(struct cfq_queue
*cfqq
, struct cfq_rq
*crq
)
627 rb_erase(&crq
->rb_node
, &cfqq
->sort_list
);
628 cfqq
->queued
[cfq_crq_is_sync(crq
)]--;
633 static struct request
*
634 cfq_find_rq_fmerge(struct cfq_data
*cfqd
, struct bio
*bio
)
636 struct task_struct
*tsk
= current
;
637 pid_t key
= cfq_queue_pid(tsk
, bio_data_dir(bio
));
638 struct cfq_queue
*cfqq
;
642 cfqq
= cfq_find_cfq_hash(cfqd
, key
, tsk
->ioprio
);
646 sector
= bio
->bi_sector
+ bio_sectors(bio
);
647 n
= cfqq
->sort_list
.rb_node
;
649 struct cfq_rq
*crq
= rb_entry_crq(n
);
651 if (sector
< crq
->rb_key
)
653 else if (sector
> crq
->rb_key
)
663 static void cfq_activate_request(request_queue_t
*q
, struct request
*rq
)
665 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
667 cfqd
->rq_in_driver
++;
670 * If the depth is larger 1, it really could be queueing. But lets
671 * make the mark a little higher - idling could still be good for
672 * low queueing, and a low queueing number could also just indicate
673 * a SCSI mid layer like behaviour where limit+1 is often seen.
675 if (!cfqd
->hw_tag
&& cfqd
->rq_in_driver
> 4)
679 static void cfq_deactivate_request(request_queue_t
*q
, struct request
*rq
)
681 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
683 WARN_ON(!cfqd
->rq_in_driver
);
684 cfqd
->rq_in_driver
--;
687 static void cfq_remove_request(struct request
*rq
)
689 struct cfq_rq
*crq
= RQ_DATA(rq
);
691 list_del_init(&rq
->queuelist
);
693 cfq_del_crq_hash(crq
);
697 cfq_merge(request_queue_t
*q
, struct request
**req
, struct bio
*bio
)
699 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
700 struct request
*__rq
;
703 __rq
= cfq_find_rq_hash(cfqd
, bio
->bi_sector
);
704 if (__rq
&& elv_rq_merge_ok(__rq
, bio
)) {
705 ret
= ELEVATOR_BACK_MERGE
;
709 __rq
= cfq_find_rq_fmerge(cfqd
, bio
);
710 if (__rq
&& elv_rq_merge_ok(__rq
, bio
)) {
711 ret
= ELEVATOR_FRONT_MERGE
;
715 return ELEVATOR_NO_MERGE
;
721 static void cfq_merged_request(request_queue_t
*q
, struct request
*req
)
723 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
724 struct cfq_rq
*crq
= RQ_DATA(req
);
726 cfq_del_crq_hash(crq
);
727 cfq_add_crq_hash(cfqd
, crq
);
729 if (rq_rb_key(req
) != crq
->rb_key
) {
730 struct cfq_queue
*cfqq
= crq
->cfq_queue
;
732 cfq_update_next_crq(crq
);
733 cfq_reposition_crq_rb(cfqq
, crq
);
738 cfq_merged_requests(request_queue_t
*q
, struct request
*rq
,
739 struct request
*next
)
741 cfq_merged_request(q
, rq
);
744 * reposition in fifo if next is older than rq
746 if (!list_empty(&rq
->queuelist
) && !list_empty(&next
->queuelist
) &&
747 time_before(next
->start_time
, rq
->start_time
))
748 list_move(&rq
->queuelist
, &next
->queuelist
);
750 cfq_remove_request(next
);
754 __cfq_set_active_queue(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
758 * stop potential idle class queues waiting service
760 del_timer(&cfqd
->idle_class_timer
);
762 cfqq
->slice_start
= jiffies
;
764 cfqq
->slice_left
= 0;
765 cfq_clear_cfqq_must_alloc_slice(cfqq
);
766 cfq_clear_cfqq_fifo_expire(cfqq
);
769 cfqd
->active_queue
= cfqq
;
773 * current cfqq expired its slice (or was too idle), select new one
776 __cfq_slice_expired(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
779 unsigned long now
= jiffies
;
781 if (cfq_cfqq_wait_request(cfqq
))
782 del_timer(&cfqd
->idle_slice_timer
);
784 if (!preempted
&& !cfq_cfqq_dispatched(cfqq
)) {
785 cfqq
->service_last
= now
;
786 cfq_schedule_dispatch(cfqd
);
789 cfq_clear_cfqq_must_dispatch(cfqq
);
790 cfq_clear_cfqq_wait_request(cfqq
);
793 * store what was left of this slice, if the queue idled out
796 if (time_after(cfqq
->slice_end
, now
))
797 cfqq
->slice_left
= cfqq
->slice_end
- now
;
799 cfqq
->slice_left
= 0;
801 if (cfq_cfqq_on_rr(cfqq
))
802 cfq_resort_rr_list(cfqq
, preempted
);
804 if (cfqq
== cfqd
->active_queue
)
805 cfqd
->active_queue
= NULL
;
807 if (cfqd
->active_cic
) {
808 put_io_context(cfqd
->active_cic
->ioc
);
809 cfqd
->active_cic
= NULL
;
812 cfqd
->dispatch_slice
= 0;
815 static inline void cfq_slice_expired(struct cfq_data
*cfqd
, int preempted
)
817 struct cfq_queue
*cfqq
= cfqd
->active_queue
;
820 __cfq_slice_expired(cfqd
, cfqq
, preempted
);
833 static int cfq_get_next_prio_level(struct cfq_data
*cfqd
)
842 for (p
= cfqd
->cur_prio
; p
<= cfqd
->cur_end_prio
; p
++) {
843 if (!list_empty(&cfqd
->rr_list
[p
])) {
852 if (++cfqd
->cur_end_prio
== CFQ_PRIO_LISTS
) {
853 cfqd
->cur_end_prio
= 0;
860 if (unlikely(prio
== -1))
863 BUG_ON(prio
>= CFQ_PRIO_LISTS
);
865 list_splice_init(&cfqd
->rr_list
[prio
], &cfqd
->cur_rr
);
867 cfqd
->cur_prio
= prio
+ 1;
868 if (cfqd
->cur_prio
> cfqd
->cur_end_prio
) {
869 cfqd
->cur_end_prio
= cfqd
->cur_prio
;
872 if (cfqd
->cur_end_prio
== CFQ_PRIO_LISTS
) {
874 cfqd
->cur_end_prio
= 0;
880 static struct cfq_queue
*cfq_set_active_queue(struct cfq_data
*cfqd
)
882 struct cfq_queue
*cfqq
= NULL
;
885 * if current list is non-empty, grab first entry. if it is empty,
886 * get next prio level and grab first entry then if any are spliced
888 if (!list_empty(&cfqd
->cur_rr
) || cfq_get_next_prio_level(cfqd
) != -1)
889 cfqq
= list_entry_cfqq(cfqd
->cur_rr
.next
);
892 * If no new queues are available, check if the busy list has some
893 * before falling back to idle io.
895 if (!cfqq
&& !list_empty(&cfqd
->busy_rr
))
896 cfqq
= list_entry_cfqq(cfqd
->busy_rr
.next
);
899 * if we have idle queues and no rt or be queues had pending
900 * requests, either allow immediate service if the grace period
901 * has passed or arm the idle grace timer
903 if (!cfqq
&& !list_empty(&cfqd
->idle_rr
)) {
904 unsigned long end
= cfqd
->last_end_request
+ CFQ_IDLE_GRACE
;
906 if (time_after_eq(jiffies
, end
))
907 cfqq
= list_entry_cfqq(cfqd
->idle_rr
.next
);
909 mod_timer(&cfqd
->idle_class_timer
, end
);
912 __cfq_set_active_queue(cfqd
, cfqq
);
916 static int cfq_arm_slice_timer(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
919 struct cfq_io_context
*cic
;
922 WARN_ON(!RB_EMPTY(&cfqq
->sort_list
));
923 WARN_ON(cfqq
!= cfqd
->active_queue
);
926 * idle is disabled, either manually or by past process history
928 if (!cfqd
->cfq_slice_idle
)
930 if (!cfq_cfqq_idle_window(cfqq
))
933 * task has exited, don't wait
935 cic
= cfqd
->active_cic
;
936 if (!cic
|| !cic
->ioc
->task
)
939 cfq_mark_cfqq_must_dispatch(cfqq
);
940 cfq_mark_cfqq_wait_request(cfqq
);
942 sl
= min(cfqq
->slice_end
- 1, (unsigned long) cfqd
->cfq_slice_idle
);
945 * we don't want to idle for seeks, but we do want to allow
946 * fair distribution of slice time for a process doing back-to-back
947 * seeks. so allow a little bit of time for him to submit a new rq
949 if (sample_valid(cic
->seek_samples
) && cic
->seek_mean
> 131072)
952 mod_timer(&cfqd
->idle_slice_timer
, jiffies
+ sl
);
956 static void cfq_dispatch_insert(request_queue_t
*q
, struct cfq_rq
*crq
)
958 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
959 struct cfq_queue
*cfqq
= crq
->cfq_queue
;
961 cfqq
->next_crq
= cfq_find_next_crq(cfqd
, cfqq
, crq
);
962 cfq_remove_request(crq
->request
);
963 cfqq
->on_dispatch
[cfq_crq_is_sync(crq
)]++;
964 elv_dispatch_sort(q
, crq
->request
);
968 * return expired entry, or NULL to just start from scratch in rbtree
970 static inline struct cfq_rq
*cfq_check_fifo(struct cfq_queue
*cfqq
)
972 struct cfq_data
*cfqd
= cfqq
->cfqd
;
976 if (cfq_cfqq_fifo_expire(cfqq
))
979 if (!list_empty(&cfqq
->fifo
)) {
980 int fifo
= cfq_cfqq_class_sync(cfqq
);
982 crq
= RQ_DATA(list_entry_fifo(cfqq
->fifo
.next
));
984 if (time_after(jiffies
, rq
->start_time
+ cfqd
->cfq_fifo_expire
[fifo
])) {
985 cfq_mark_cfqq_fifo_expire(cfqq
);
994 * Scale schedule slice based on io priority. Use the sync time slice only
995 * if a queue is marked sync and has sync io queued. A sync queue with async
996 * io only, should not get full sync slice length.
999 cfq_prio_to_slice(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
1001 const int base_slice
= cfqd
->cfq_slice
[cfq_cfqq_sync(cfqq
)];
1003 WARN_ON(cfqq
->ioprio
>= IOPRIO_BE_NR
);
1005 return base_slice
+ (base_slice
/CFQ_SLICE_SCALE
* (4 - cfqq
->ioprio
));
1009 cfq_set_prio_slice(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
1011 cfqq
->slice_end
= cfq_prio_to_slice(cfqd
, cfqq
) + jiffies
;
1015 cfq_prio_to_maxrq(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
1017 const int base_rq
= cfqd
->cfq_slice_async_rq
;
1019 WARN_ON(cfqq
->ioprio
>= IOPRIO_BE_NR
);
1021 return 2 * (base_rq
+ base_rq
* (CFQ_PRIO_LISTS
- 1 - cfqq
->ioprio
));
1025 * get next queue for service
1027 static struct cfq_queue
*cfq_select_queue(struct cfq_data
*cfqd
)
1029 unsigned long now
= jiffies
;
1030 struct cfq_queue
*cfqq
;
1032 cfqq
= cfqd
->active_queue
;
1039 if (!cfq_cfqq_must_dispatch(cfqq
) && time_after(now
, cfqq
->slice_end
))
1043 * if queue has requests, dispatch one. if not, check if
1044 * enough slice is left to wait for one
1046 if (!RB_EMPTY(&cfqq
->sort_list
))
1048 else if (cfq_cfqq_class_sync(cfqq
) &&
1049 time_before(now
, cfqq
->slice_end
)) {
1050 if (cfq_arm_slice_timer(cfqd
, cfqq
))
1055 cfq_slice_expired(cfqd
, 0);
1057 cfqq
= cfq_set_active_queue(cfqd
);
1063 __cfq_dispatch_requests(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
1068 BUG_ON(RB_EMPTY(&cfqq
->sort_list
));
1074 * follow expired path, else get first next available
1076 if ((crq
= cfq_check_fifo(cfqq
)) == NULL
)
1077 crq
= cfqq
->next_crq
;
1080 * finally, insert request into driver dispatch list
1082 cfq_dispatch_insert(cfqd
->queue
, crq
);
1084 cfqd
->dispatch_slice
++;
1087 if (!cfqd
->active_cic
) {
1088 atomic_inc(&crq
->io_context
->ioc
->refcount
);
1089 cfqd
->active_cic
= crq
->io_context
;
1092 if (RB_EMPTY(&cfqq
->sort_list
))
1095 } while (dispatched
< max_dispatch
);
1098 * if slice end isn't set yet, set it. if at least one request was
1099 * sync, use the sync time slice value
1101 if (!cfqq
->slice_end
)
1102 cfq_set_prio_slice(cfqd
, cfqq
);
1105 * expire an async queue immediately if it has used up its slice. idle
1106 * queue always expire after 1 dispatch round.
1108 if ((!cfq_cfqq_sync(cfqq
) &&
1109 cfqd
->dispatch_slice
>= cfq_prio_to_maxrq(cfqd
, cfqq
)) ||
1110 cfq_class_idle(cfqq
))
1111 cfq_slice_expired(cfqd
, 0);
1117 cfq_forced_dispatch_cfqqs(struct list_head
*list
)
1120 struct cfq_queue
*cfqq
, *next
;
1123 list_for_each_entry_safe(cfqq
, next
, list
, cfq_list
) {
1124 while ((crq
= cfqq
->next_crq
)) {
1125 cfq_dispatch_insert(cfqq
->cfqd
->queue
, crq
);
1128 BUG_ON(!list_empty(&cfqq
->fifo
));
1134 cfq_forced_dispatch(struct cfq_data
*cfqd
)
1136 int i
, dispatched
= 0;
1138 for (i
= 0; i
< CFQ_PRIO_LISTS
; i
++)
1139 dispatched
+= cfq_forced_dispatch_cfqqs(&cfqd
->rr_list
[i
]);
1141 dispatched
+= cfq_forced_dispatch_cfqqs(&cfqd
->busy_rr
);
1142 dispatched
+= cfq_forced_dispatch_cfqqs(&cfqd
->cur_rr
);
1143 dispatched
+= cfq_forced_dispatch_cfqqs(&cfqd
->idle_rr
);
1145 cfq_slice_expired(cfqd
, 0);
1147 BUG_ON(cfqd
->busy_queues
);
1153 cfq_dispatch_requests(request_queue_t
*q
, int force
)
1155 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
1156 struct cfq_queue
*cfqq
;
1158 if (!cfqd
->busy_queues
)
1161 if (unlikely(force
))
1162 return cfq_forced_dispatch(cfqd
);
1164 cfqq
= cfq_select_queue(cfqd
);
1168 cfq_clear_cfqq_must_dispatch(cfqq
);
1169 cfq_clear_cfqq_wait_request(cfqq
);
1170 del_timer(&cfqd
->idle_slice_timer
);
1172 max_dispatch
= cfqd
->cfq_quantum
;
1173 if (cfq_class_idle(cfqq
))
1176 return __cfq_dispatch_requests(cfqd
, cfqq
, max_dispatch
);
1183 * task holds one reference to the queue, dropped when task exits. each crq
1184 * in-flight on this queue also holds a reference, dropped when crq is freed.
1186 * queue lock must be held here.
1188 static void cfq_put_queue(struct cfq_queue
*cfqq
)
1190 struct cfq_data
*cfqd
= cfqq
->cfqd
;
1192 BUG_ON(atomic_read(&cfqq
->ref
) <= 0);
1194 if (!atomic_dec_and_test(&cfqq
->ref
))
1197 BUG_ON(rb_first(&cfqq
->sort_list
));
1198 BUG_ON(cfqq
->allocated
[READ
] + cfqq
->allocated
[WRITE
]);
1199 BUG_ON(cfq_cfqq_on_rr(cfqq
));
1201 if (unlikely(cfqd
->active_queue
== cfqq
))
1202 __cfq_slice_expired(cfqd
, cfqq
, 0);
1205 * it's on the empty list and still hashed
1207 list_del(&cfqq
->cfq_list
);
1208 hlist_del(&cfqq
->cfq_hash
);
1209 kmem_cache_free(cfq_pool
, cfqq
);
1212 static inline struct cfq_queue
*
1213 __cfq_find_cfq_hash(struct cfq_data
*cfqd
, unsigned int key
, unsigned int prio
,
1216 struct hlist_head
*hash_list
= &cfqd
->cfq_hash
[hashval
];
1217 struct hlist_node
*entry
;
1218 struct cfq_queue
*__cfqq
;
1220 hlist_for_each_entry(__cfqq
, entry
, hash_list
, cfq_hash
) {
1221 const unsigned short __p
= IOPRIO_PRIO_VALUE(__cfqq
->org_ioprio_class
, __cfqq
->org_ioprio
);
1223 if (__cfqq
->key
== key
&& (__p
== prio
|| !prio
))
1230 static struct cfq_queue
*
1231 cfq_find_cfq_hash(struct cfq_data
*cfqd
, unsigned int key
, unsigned short prio
)
1233 return __cfq_find_cfq_hash(cfqd
, key
, prio
, hash_long(key
, CFQ_QHASH_SHIFT
));
1236 static void cfq_free_io_context(struct io_context
*ioc
)
1238 struct cfq_io_context
*__cic
;
1242 while ((n
= rb_first(&ioc
->cic_root
)) != NULL
) {
1243 __cic
= rb_entry(n
, struct cfq_io_context
, rb_node
);
1244 rb_erase(&__cic
->rb_node
, &ioc
->cic_root
);
1245 kmem_cache_free(cfq_ioc_pool
, __cic
);
1249 if (atomic_sub_and_test(freed
, &ioc_count
) && ioc_gone
)
1253 static void cfq_trim(struct io_context
*ioc
)
1255 ioc
->set_ioprio
= NULL
;
1256 cfq_free_io_context(ioc
);
1260 * Called with interrupts disabled
1262 static void cfq_exit_single_io_context(struct cfq_io_context
*cic
)
1264 struct cfq_data
*cfqd
= cic
->key
;
1272 WARN_ON(!irqs_disabled());
1274 spin_lock(q
->queue_lock
);
1276 if (cic
->cfqq
[ASYNC
]) {
1277 if (unlikely(cic
->cfqq
[ASYNC
] == cfqd
->active_queue
))
1278 __cfq_slice_expired(cfqd
, cic
->cfqq
[ASYNC
], 0);
1279 cfq_put_queue(cic
->cfqq
[ASYNC
]);
1280 cic
->cfqq
[ASYNC
] = NULL
;
1283 if (cic
->cfqq
[SYNC
]) {
1284 if (unlikely(cic
->cfqq
[SYNC
] == cfqd
->active_queue
))
1285 __cfq_slice_expired(cfqd
, cic
->cfqq
[SYNC
], 0);
1286 cfq_put_queue(cic
->cfqq
[SYNC
]);
1287 cic
->cfqq
[SYNC
] = NULL
;
1291 list_del_init(&cic
->queue_list
);
1292 spin_unlock(q
->queue_lock
);
1295 static void cfq_exit_io_context(struct io_context
*ioc
)
1297 struct cfq_io_context
*__cic
;
1298 unsigned long flags
;
1302 * put the reference this task is holding to the various queues
1304 spin_lock_irqsave(&cfq_exit_lock
, flags
);
1306 n
= rb_first(&ioc
->cic_root
);
1308 __cic
= rb_entry(n
, struct cfq_io_context
, rb_node
);
1310 cfq_exit_single_io_context(__cic
);
1314 spin_unlock_irqrestore(&cfq_exit_lock
, flags
);
1317 static struct cfq_io_context
*
1318 cfq_alloc_io_context(struct cfq_data
*cfqd
, gfp_t gfp_mask
)
1320 struct cfq_io_context
*cic
= kmem_cache_alloc(cfq_ioc_pool
, gfp_mask
);
1323 RB_CLEAR(&cic
->rb_node
);
1325 cic
->cfqq
[ASYNC
] = NULL
;
1326 cic
->cfqq
[SYNC
] = NULL
;
1327 cic
->last_end_request
= jiffies
;
1328 cic
->ttime_total
= 0;
1329 cic
->ttime_samples
= 0;
1330 cic
->ttime_mean
= 0;
1331 cic
->dtor
= cfq_free_io_context
;
1332 cic
->exit
= cfq_exit_io_context
;
1333 INIT_LIST_HEAD(&cic
->queue_list
);
1334 atomic_inc(&ioc_count
);
1340 static void cfq_init_prio_data(struct cfq_queue
*cfqq
)
1342 struct task_struct
*tsk
= current
;
1345 if (!cfq_cfqq_prio_changed(cfqq
))
1348 ioprio_class
= IOPRIO_PRIO_CLASS(tsk
->ioprio
);
1349 switch (ioprio_class
) {
1351 printk(KERN_ERR
"cfq: bad prio %x\n", ioprio_class
);
1352 case IOPRIO_CLASS_NONE
:
1354 * no prio set, place us in the middle of the BE classes
1356 cfqq
->ioprio
= task_nice_ioprio(tsk
);
1357 cfqq
->ioprio_class
= IOPRIO_CLASS_BE
;
1359 case IOPRIO_CLASS_RT
:
1360 cfqq
->ioprio
= task_ioprio(tsk
);
1361 cfqq
->ioprio_class
= IOPRIO_CLASS_RT
;
1363 case IOPRIO_CLASS_BE
:
1364 cfqq
->ioprio
= task_ioprio(tsk
);
1365 cfqq
->ioprio_class
= IOPRIO_CLASS_BE
;
1367 case IOPRIO_CLASS_IDLE
:
1368 cfqq
->ioprio_class
= IOPRIO_CLASS_IDLE
;
1370 cfq_clear_cfqq_idle_window(cfqq
);
1375 * keep track of original prio settings in case we have to temporarily
1376 * elevate the priority of this queue
1378 cfqq
->org_ioprio
= cfqq
->ioprio
;
1379 cfqq
->org_ioprio_class
= cfqq
->ioprio_class
;
1381 if (cfq_cfqq_on_rr(cfqq
))
1382 cfq_resort_rr_list(cfqq
, 0);
1384 cfq_clear_cfqq_prio_changed(cfqq
);
1387 static inline void changed_ioprio(struct cfq_io_context
*cic
)
1389 struct cfq_data
*cfqd
= cic
->key
;
1390 struct cfq_queue
*cfqq
;
1392 spin_lock(cfqd
->queue
->queue_lock
);
1393 cfqq
= cic
->cfqq
[ASYNC
];
1395 struct cfq_queue
*new_cfqq
;
1396 new_cfqq
= cfq_get_queue(cfqd
, CFQ_KEY_ASYNC
,
1397 cic
->ioc
->task
, GFP_ATOMIC
);
1399 cic
->cfqq
[ASYNC
] = new_cfqq
;
1400 cfq_put_queue(cfqq
);
1403 cfqq
= cic
->cfqq
[SYNC
];
1405 cfq_mark_cfqq_prio_changed(cfqq
);
1406 cfq_init_prio_data(cfqq
);
1408 spin_unlock(cfqd
->queue
->queue_lock
);
1413 * callback from sys_ioprio_set, irqs are disabled
1415 static int cfq_ioc_set_ioprio(struct io_context
*ioc
, unsigned int ioprio
)
1417 struct cfq_io_context
*cic
;
1420 spin_lock(&cfq_exit_lock
);
1422 n
= rb_first(&ioc
->cic_root
);
1424 cic
= rb_entry(n
, struct cfq_io_context
, rb_node
);
1426 changed_ioprio(cic
);
1430 spin_unlock(&cfq_exit_lock
);
1435 static struct cfq_queue
*
1436 cfq_get_queue(struct cfq_data
*cfqd
, unsigned int key
, struct task_struct
*tsk
,
1439 const int hashval
= hash_long(key
, CFQ_QHASH_SHIFT
);
1440 struct cfq_queue
*cfqq
, *new_cfqq
= NULL
;
1441 unsigned short ioprio
;
1444 ioprio
= tsk
->ioprio
;
1445 cfqq
= __cfq_find_cfq_hash(cfqd
, key
, ioprio
, hashval
);
1451 } else if (gfp_mask
& __GFP_WAIT
) {
1452 spin_unlock_irq(cfqd
->queue
->queue_lock
);
1453 new_cfqq
= kmem_cache_alloc(cfq_pool
, gfp_mask
);
1454 spin_lock_irq(cfqd
->queue
->queue_lock
);
1457 cfqq
= kmem_cache_alloc(cfq_pool
, gfp_mask
);
1462 memset(cfqq
, 0, sizeof(*cfqq
));
1464 INIT_HLIST_NODE(&cfqq
->cfq_hash
);
1465 INIT_LIST_HEAD(&cfqq
->cfq_list
);
1466 RB_CLEAR_ROOT(&cfqq
->sort_list
);
1467 INIT_LIST_HEAD(&cfqq
->fifo
);
1470 hlist_add_head(&cfqq
->cfq_hash
, &cfqd
->cfq_hash
[hashval
]);
1471 atomic_set(&cfqq
->ref
, 0);
1473 cfqq
->service_last
= 0;
1475 * set ->slice_left to allow preemption for a new process
1477 cfqq
->slice_left
= 2 * cfqd
->cfq_slice_idle
;
1479 cfq_mark_cfqq_idle_window(cfqq
);
1480 cfq_mark_cfqq_prio_changed(cfqq
);
1481 cfq_init_prio_data(cfqq
);
1485 kmem_cache_free(cfq_pool
, new_cfqq
);
1487 atomic_inc(&cfqq
->ref
);
1489 WARN_ON((gfp_mask
& __GFP_WAIT
) && !cfqq
);
1494 cfq_drop_dead_cic(struct io_context
*ioc
, struct cfq_io_context
*cic
)
1496 spin_lock(&cfq_exit_lock
);
1497 rb_erase(&cic
->rb_node
, &ioc
->cic_root
);
1498 list_del_init(&cic
->queue_list
);
1499 spin_unlock(&cfq_exit_lock
);
1500 kmem_cache_free(cfq_ioc_pool
, cic
);
1501 atomic_dec(&ioc_count
);
1504 static struct cfq_io_context
*
1505 cfq_cic_rb_lookup(struct cfq_data
*cfqd
, struct io_context
*ioc
)
1508 struct cfq_io_context
*cic
;
1509 void *k
, *key
= cfqd
;
1512 n
= ioc
->cic_root
.rb_node
;
1514 cic
= rb_entry(n
, struct cfq_io_context
, rb_node
);
1515 /* ->key must be copied to avoid race with cfq_exit_queue() */
1518 cfq_drop_dead_cic(ioc
, cic
);
1534 cfq_cic_link(struct cfq_data
*cfqd
, struct io_context
*ioc
,
1535 struct cfq_io_context
*cic
)
1538 struct rb_node
*parent
;
1539 struct cfq_io_context
*__cic
;
1545 ioc
->set_ioprio
= cfq_ioc_set_ioprio
;
1548 p
= &ioc
->cic_root
.rb_node
;
1551 __cic
= rb_entry(parent
, struct cfq_io_context
, rb_node
);
1552 /* ->key must be copied to avoid race with cfq_exit_queue() */
1555 cfq_drop_dead_cic(ioc
, cic
);
1561 else if (cic
->key
> k
)
1562 p
= &(*p
)->rb_right
;
1567 spin_lock(&cfq_exit_lock
);
1568 rb_link_node(&cic
->rb_node
, parent
, p
);
1569 rb_insert_color(&cic
->rb_node
, &ioc
->cic_root
);
1570 list_add(&cic
->queue_list
, &cfqd
->cic_list
);
1571 spin_unlock(&cfq_exit_lock
);
1575 * Setup general io context and cfq io context. There can be several cfq
1576 * io contexts per general io context, if this process is doing io to more
1577 * than one device managed by cfq.
1579 static struct cfq_io_context
*
1580 cfq_get_io_context(struct cfq_data
*cfqd
, gfp_t gfp_mask
)
1582 struct io_context
*ioc
= NULL
;
1583 struct cfq_io_context
*cic
;
1585 might_sleep_if(gfp_mask
& __GFP_WAIT
);
1587 ioc
= get_io_context(gfp_mask
);
1591 cic
= cfq_cic_rb_lookup(cfqd
, ioc
);
1595 cic
= cfq_alloc_io_context(cfqd
, gfp_mask
);
1599 cfq_cic_link(cfqd
, ioc
, cic
);
1603 put_io_context(ioc
);
1608 cfq_update_io_thinktime(struct cfq_data
*cfqd
, struct cfq_io_context
*cic
)
1610 unsigned long elapsed
, ttime
;
1613 * if this context already has stuff queued, thinktime is from
1614 * last queue not last end
1617 if (time_after(cic
->last_end_request
, cic
->last_queue
))
1618 elapsed
= jiffies
- cic
->last_end_request
;
1620 elapsed
= jiffies
- cic
->last_queue
;
1622 elapsed
= jiffies
- cic
->last_end_request
;
1625 ttime
= min(elapsed
, 2UL * cfqd
->cfq_slice_idle
);
1627 cic
->ttime_samples
= (7*cic
->ttime_samples
+ 256) / 8;
1628 cic
->ttime_total
= (7*cic
->ttime_total
+ 256*ttime
) / 8;
1629 cic
->ttime_mean
= (cic
->ttime_total
+ 128) / cic
->ttime_samples
;
1633 cfq_update_io_seektime(struct cfq_data
*cfqd
, struct cfq_io_context
*cic
,
1639 if (cic
->last_request_pos
< crq
->request
->sector
)
1640 sdist
= crq
->request
->sector
- cic
->last_request_pos
;
1642 sdist
= cic
->last_request_pos
- crq
->request
->sector
;
1645 * Don't allow the seek distance to get too large from the
1646 * odd fragment, pagein, etc
1648 if (cic
->seek_samples
<= 60) /* second&third seek */
1649 sdist
= min(sdist
, (cic
->seek_mean
* 4) + 2*1024*1024);
1651 sdist
= min(sdist
, (cic
->seek_mean
* 4) + 2*1024*64);
1653 cic
->seek_samples
= (7*cic
->seek_samples
+ 256) / 8;
1654 cic
->seek_total
= (7*cic
->seek_total
+ (u64
)256*sdist
) / 8;
1655 total
= cic
->seek_total
+ (cic
->seek_samples
/2);
1656 do_div(total
, cic
->seek_samples
);
1657 cic
->seek_mean
= (sector_t
)total
;
1661 * Disable idle window if the process thinks too long or seeks so much that
1665 cfq_update_idle_window(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
1666 struct cfq_io_context
*cic
)
1668 int enable_idle
= cfq_cfqq_idle_window(cfqq
);
1670 if (!cic
->ioc
->task
|| !cfqd
->cfq_slice_idle
|| cfqd
->hw_tag
)
1672 else if (sample_valid(cic
->ttime_samples
)) {
1673 if (cic
->ttime_mean
> cfqd
->cfq_slice_idle
)
1680 cfq_mark_cfqq_idle_window(cfqq
);
1682 cfq_clear_cfqq_idle_window(cfqq
);
1687 * Check if new_cfqq should preempt the currently active queue. Return 0 for
1688 * no or if we aren't sure, a 1 will cause a preempt.
1691 cfq_should_preempt(struct cfq_data
*cfqd
, struct cfq_queue
*new_cfqq
,
1694 struct cfq_queue
*cfqq
= cfqd
->active_queue
;
1696 if (cfq_class_idle(new_cfqq
))
1702 if (cfq_class_idle(cfqq
))
1704 if (!cfq_cfqq_wait_request(new_cfqq
))
1707 * if it doesn't have slice left, forget it
1709 if (new_cfqq
->slice_left
< cfqd
->cfq_slice_idle
)
1711 if (cfq_crq_is_sync(crq
) && !cfq_cfqq_sync(cfqq
))
1718 * cfqq preempts the active queue. if we allowed preempt with no slice left,
1719 * let it have half of its nominal slice.
1721 static void cfq_preempt_queue(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
1723 struct cfq_queue
*__cfqq
, *next
;
1725 list_for_each_entry_safe(__cfqq
, next
, &cfqd
->cur_rr
, cfq_list
)
1726 cfq_resort_rr_list(__cfqq
, 1);
1728 if (!cfqq
->slice_left
)
1729 cfqq
->slice_left
= cfq_prio_to_slice(cfqd
, cfqq
) / 2;
1731 cfqq
->slice_end
= cfqq
->slice_left
+ jiffies
;
1732 __cfq_slice_expired(cfqd
, cfqq
, 1);
1733 __cfq_set_active_queue(cfqd
, cfqq
);
1737 * should really be a ll_rw_blk.c helper
1739 static void cfq_start_queueing(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
1741 request_queue_t
*q
= cfqd
->queue
;
1743 if (!blk_queue_plugged(q
))
1746 __generic_unplug_device(q
);
1750 * Called when a new fs request (crq) is added (to cfqq). Check if there's
1751 * something we should do about it
1754 cfq_crq_enqueued(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
1757 struct cfq_io_context
*cic
;
1759 cfqq
->next_crq
= cfq_choose_req(cfqd
, cfqq
->next_crq
, crq
);
1761 cic
= crq
->io_context
;
1764 * we never wait for an async request and we don't allow preemption
1765 * of an async request. so just return early
1767 if (!cfq_crq_is_sync(crq
)) {
1769 * sync process issued an async request, if it's waiting
1770 * then expire it and kick rq handling.
1772 if (cic
== cfqd
->active_cic
&&
1773 del_timer(&cfqd
->idle_slice_timer
)) {
1774 cfq_slice_expired(cfqd
, 0);
1775 cfq_start_queueing(cfqd
, cfqq
);
1780 cfq_update_io_thinktime(cfqd
, cic
);
1781 cfq_update_io_seektime(cfqd
, cic
, crq
);
1782 cfq_update_idle_window(cfqd
, cfqq
, cic
);
1784 cic
->last_queue
= jiffies
;
1785 cic
->last_request_pos
= crq
->request
->sector
+ crq
->request
->nr_sectors
;
1787 if (cfqq
== cfqd
->active_queue
) {
1789 * if we are waiting for a request for this queue, let it rip
1790 * immediately and flag that we must not expire this queue
1793 if (cfq_cfqq_wait_request(cfqq
)) {
1794 cfq_mark_cfqq_must_dispatch(cfqq
);
1795 del_timer(&cfqd
->idle_slice_timer
);
1796 cfq_start_queueing(cfqd
, cfqq
);
1798 } else if (cfq_should_preempt(cfqd
, cfqq
, crq
)) {
1800 * not the active queue - expire current slice if it is
1801 * idle and has expired it's mean thinktime or this new queue
1802 * has some old slice time left and is of higher priority
1804 cfq_preempt_queue(cfqd
, cfqq
);
1805 cfq_mark_cfqq_must_dispatch(cfqq
);
1806 cfq_start_queueing(cfqd
, cfqq
);
1810 static void cfq_insert_request(request_queue_t
*q
, struct request
*rq
)
1812 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
1813 struct cfq_rq
*crq
= RQ_DATA(rq
);
1814 struct cfq_queue
*cfqq
= crq
->cfq_queue
;
1816 cfq_init_prio_data(cfqq
);
1818 cfq_add_crq_rb(crq
);
1820 list_add_tail(&rq
->queuelist
, &cfqq
->fifo
);
1822 if (rq_mergeable(rq
))
1823 cfq_add_crq_hash(cfqd
, crq
);
1825 cfq_crq_enqueued(cfqd
, cfqq
, crq
);
1828 static void cfq_completed_request(request_queue_t
*q
, struct request
*rq
)
1830 struct cfq_rq
*crq
= RQ_DATA(rq
);
1831 struct cfq_queue
*cfqq
= crq
->cfq_queue
;
1832 struct cfq_data
*cfqd
= cfqq
->cfqd
;
1833 const int sync
= cfq_crq_is_sync(crq
);
1838 WARN_ON(!cfqd
->rq_in_driver
);
1839 WARN_ON(!cfqq
->on_dispatch
[sync
]);
1840 cfqd
->rq_in_driver
--;
1841 cfqq
->on_dispatch
[sync
]--;
1843 if (!cfq_class_idle(cfqq
))
1844 cfqd
->last_end_request
= now
;
1846 if (!cfq_cfqq_dispatched(cfqq
)) {
1847 if (cfq_cfqq_on_rr(cfqq
)) {
1848 cfqq
->service_last
= now
;
1849 cfq_resort_rr_list(cfqq
, 0);
1851 cfq_schedule_dispatch(cfqd
);
1854 if (cfq_crq_is_sync(crq
))
1855 crq
->io_context
->last_end_request
= now
;
1858 static struct request
*
1859 cfq_former_request(request_queue_t
*q
, struct request
*rq
)
1861 struct cfq_rq
*crq
= RQ_DATA(rq
);
1862 struct rb_node
*rbprev
= rb_prev(&crq
->rb_node
);
1865 return rb_entry_crq(rbprev
)->request
;
1870 static struct request
*
1871 cfq_latter_request(request_queue_t
*q
, struct request
*rq
)
1873 struct cfq_rq
*crq
= RQ_DATA(rq
);
1874 struct rb_node
*rbnext
= rb_next(&crq
->rb_node
);
1877 return rb_entry_crq(rbnext
)->request
;
1883 * we temporarily boost lower priority queues if they are holding fs exclusive
1884 * resources. they are boosted to normal prio (CLASS_BE/4)
1886 static void cfq_prio_boost(struct cfq_queue
*cfqq
)
1888 const int ioprio_class
= cfqq
->ioprio_class
;
1889 const int ioprio
= cfqq
->ioprio
;
1891 if (has_fs_excl()) {
1893 * boost idle prio on transactions that would lock out other
1894 * users of the filesystem
1896 if (cfq_class_idle(cfqq
))
1897 cfqq
->ioprio_class
= IOPRIO_CLASS_BE
;
1898 if (cfqq
->ioprio
> IOPRIO_NORM
)
1899 cfqq
->ioprio
= IOPRIO_NORM
;
1902 * check if we need to unboost the queue
1904 if (cfqq
->ioprio_class
!= cfqq
->org_ioprio_class
)
1905 cfqq
->ioprio_class
= cfqq
->org_ioprio_class
;
1906 if (cfqq
->ioprio
!= cfqq
->org_ioprio
)
1907 cfqq
->ioprio
= cfqq
->org_ioprio
;
1911 * refile between round-robin lists if we moved the priority class
1913 if ((ioprio_class
!= cfqq
->ioprio_class
|| ioprio
!= cfqq
->ioprio
) &&
1914 cfq_cfqq_on_rr(cfqq
))
1915 cfq_resort_rr_list(cfqq
, 0);
1919 __cfq_may_queue(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
1920 struct task_struct
*task
, int rw
)
1923 if ((cfq_cfqq_wait_request(cfqq
) || cfq_cfqq_must_alloc(cfqq
)) &&
1924 !cfq_cfqq_must_alloc_slice(cfqq
)) {
1925 cfq_mark_cfqq_must_alloc_slice(cfqq
);
1926 return ELV_MQUEUE_MUST
;
1929 return ELV_MQUEUE_MAY
;
1931 if (!cfqq
|| task
->flags
& PF_MEMALLOC
)
1932 return ELV_MQUEUE_MAY
;
1933 if (!cfqq
->allocated
[rw
] || cfq_cfqq_must_alloc(cfqq
)) {
1934 if (cfq_cfqq_wait_request(cfqq
))
1935 return ELV_MQUEUE_MUST
;
1938 * only allow 1 ELV_MQUEUE_MUST per slice, otherwise we
1939 * can quickly flood the queue with writes from a single task
1941 if (rw
== READ
|| !cfq_cfqq_must_alloc_slice(cfqq
)) {
1942 cfq_mark_cfqq_must_alloc_slice(cfqq
);
1943 return ELV_MQUEUE_MUST
;
1946 return ELV_MQUEUE_MAY
;
1948 if (cfq_class_idle(cfqq
))
1949 return ELV_MQUEUE_NO
;
1950 if (cfqq
->allocated
[rw
] >= cfqd
->max_queued
) {
1951 struct io_context
*ioc
= get_io_context(GFP_ATOMIC
);
1952 int ret
= ELV_MQUEUE_NO
;
1954 if (ioc
&& ioc
->nr_batch_requests
)
1955 ret
= ELV_MQUEUE_MAY
;
1957 put_io_context(ioc
);
1961 return ELV_MQUEUE_MAY
;
1965 static int cfq_may_queue(request_queue_t
*q
, int rw
, struct bio
*bio
)
1967 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
1968 struct task_struct
*tsk
= current
;
1969 struct cfq_queue
*cfqq
;
1972 * don't force setup of a queue from here, as a call to may_queue
1973 * does not necessarily imply that a request actually will be queued.
1974 * so just lookup a possibly existing queue, or return 'may queue'
1977 cfqq
= cfq_find_cfq_hash(cfqd
, cfq_queue_pid(tsk
, rw
), tsk
->ioprio
);
1979 cfq_init_prio_data(cfqq
);
1980 cfq_prio_boost(cfqq
);
1982 return __cfq_may_queue(cfqd
, cfqq
, tsk
, rw
);
1985 return ELV_MQUEUE_MAY
;
1988 static void cfq_check_waiters(request_queue_t
*q
, struct cfq_queue
*cfqq
)
1990 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
1991 struct request_list
*rl
= &q
->rq
;
1993 if (cfqq
->allocated
[READ
] <= cfqd
->max_queued
|| cfqd
->rq_starved
) {
1995 if (waitqueue_active(&rl
->wait
[READ
]))
1996 wake_up(&rl
->wait
[READ
]);
1999 if (cfqq
->allocated
[WRITE
] <= cfqd
->max_queued
|| cfqd
->rq_starved
) {
2001 if (waitqueue_active(&rl
->wait
[WRITE
]))
2002 wake_up(&rl
->wait
[WRITE
]);
2007 * queue lock held here
2009 static void cfq_put_request(request_queue_t
*q
, struct request
*rq
)
2011 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
2012 struct cfq_rq
*crq
= RQ_DATA(rq
);
2015 struct cfq_queue
*cfqq
= crq
->cfq_queue
;
2016 const int rw
= rq_data_dir(rq
);
2018 BUG_ON(!cfqq
->allocated
[rw
]);
2019 cfqq
->allocated
[rw
]--;
2021 put_io_context(crq
->io_context
->ioc
);
2023 mempool_free(crq
, cfqd
->crq_pool
);
2024 rq
->elevator_private
= NULL
;
2026 cfq_check_waiters(q
, cfqq
);
2027 cfq_put_queue(cfqq
);
2032 * Allocate cfq data structures associated with this request.
2035 cfq_set_request(request_queue_t
*q
, struct request
*rq
, struct bio
*bio
,
2038 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
2039 struct task_struct
*tsk
= current
;
2040 struct cfq_io_context
*cic
;
2041 const int rw
= rq_data_dir(rq
);
2042 pid_t key
= cfq_queue_pid(tsk
, rw
);
2043 struct cfq_queue
*cfqq
;
2045 unsigned long flags
;
2046 int is_sync
= key
!= CFQ_KEY_ASYNC
;
2048 might_sleep_if(gfp_mask
& __GFP_WAIT
);
2050 cic
= cfq_get_io_context(cfqd
, gfp_mask
);
2052 spin_lock_irqsave(q
->queue_lock
, flags
);
2057 if (!cic
->cfqq
[is_sync
]) {
2058 cfqq
= cfq_get_queue(cfqd
, key
, tsk
, gfp_mask
);
2062 cic
->cfqq
[is_sync
] = cfqq
;
2064 cfqq
= cic
->cfqq
[is_sync
];
2066 cfqq
->allocated
[rw
]++;
2067 cfq_clear_cfqq_must_alloc(cfqq
);
2068 cfqd
->rq_starved
= 0;
2069 atomic_inc(&cfqq
->ref
);
2070 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2072 crq
= mempool_alloc(cfqd
->crq_pool
, gfp_mask
);
2074 RB_CLEAR(&crq
->rb_node
);
2077 INIT_HLIST_NODE(&crq
->hash
);
2078 crq
->cfq_queue
= cfqq
;
2079 crq
->io_context
= cic
;
2082 cfq_mark_crq_is_sync(crq
);
2084 cfq_clear_crq_is_sync(crq
);
2086 rq
->elevator_private
= crq
;
2090 spin_lock_irqsave(q
->queue_lock
, flags
);
2091 cfqq
->allocated
[rw
]--;
2092 if (!(cfqq
->allocated
[0] + cfqq
->allocated
[1]))
2093 cfq_mark_cfqq_must_alloc(cfqq
);
2094 cfq_put_queue(cfqq
);
2097 put_io_context(cic
->ioc
);
2099 * mark us rq allocation starved. we need to kickstart the process
2100 * ourselves if there are no pending requests that can do it for us.
2101 * that would be an extremely rare OOM situation
2103 cfqd
->rq_starved
= 1;
2104 cfq_schedule_dispatch(cfqd
);
2105 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2109 static void cfq_kick_queue(void *data
)
2111 request_queue_t
*q
= data
;
2112 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
2113 unsigned long flags
;
2115 spin_lock_irqsave(q
->queue_lock
, flags
);
2117 if (cfqd
->rq_starved
) {
2118 struct request_list
*rl
= &q
->rq
;
2121 * we aren't guaranteed to get a request after this, but we
2122 * have to be opportunistic
2125 if (waitqueue_active(&rl
->wait
[READ
]))
2126 wake_up(&rl
->wait
[READ
]);
2127 if (waitqueue_active(&rl
->wait
[WRITE
]))
2128 wake_up(&rl
->wait
[WRITE
]);
2133 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2137 * Timer running if the active_queue is currently idling inside its time slice
2139 static void cfq_idle_slice_timer(unsigned long data
)
2141 struct cfq_data
*cfqd
= (struct cfq_data
*) data
;
2142 struct cfq_queue
*cfqq
;
2143 unsigned long flags
;
2145 spin_lock_irqsave(cfqd
->queue
->queue_lock
, flags
);
2147 if ((cfqq
= cfqd
->active_queue
) != NULL
) {
2148 unsigned long now
= jiffies
;
2153 if (time_after(now
, cfqq
->slice_end
))
2157 * only expire and reinvoke request handler, if there are
2158 * other queues with pending requests
2160 if (!cfqd
->busy_queues
) {
2161 cfqd
->idle_slice_timer
.expires
= min(now
+ cfqd
->cfq_slice_idle
, cfqq
->slice_end
);
2162 add_timer(&cfqd
->idle_slice_timer
);
2167 * not expired and it has a request pending, let it dispatch
2169 if (!RB_EMPTY(&cfqq
->sort_list
)) {
2170 cfq_mark_cfqq_must_dispatch(cfqq
);
2175 cfq_slice_expired(cfqd
, 0);
2177 cfq_schedule_dispatch(cfqd
);
2179 spin_unlock_irqrestore(cfqd
->queue
->queue_lock
, flags
);
2183 * Timer running if an idle class queue is waiting for service
2185 static void cfq_idle_class_timer(unsigned long data
)
2187 struct cfq_data
*cfqd
= (struct cfq_data
*) data
;
2188 unsigned long flags
, end
;
2190 spin_lock_irqsave(cfqd
->queue
->queue_lock
, flags
);
2193 * race with a non-idle queue, reset timer
2195 end
= cfqd
->last_end_request
+ CFQ_IDLE_GRACE
;
2196 if (!time_after_eq(jiffies
, end
)) {
2197 cfqd
->idle_class_timer
.expires
= end
;
2198 add_timer(&cfqd
->idle_class_timer
);
2200 cfq_schedule_dispatch(cfqd
);
2202 spin_unlock_irqrestore(cfqd
->queue
->queue_lock
, flags
);
2205 static void cfq_shutdown_timer_wq(struct cfq_data
*cfqd
)
2207 del_timer_sync(&cfqd
->idle_slice_timer
);
2208 del_timer_sync(&cfqd
->idle_class_timer
);
2209 blk_sync_queue(cfqd
->queue
);
2212 static void cfq_exit_queue(elevator_t
*e
)
2214 struct cfq_data
*cfqd
= e
->elevator_data
;
2215 request_queue_t
*q
= cfqd
->queue
;
2217 cfq_shutdown_timer_wq(cfqd
);
2219 spin_lock(&cfq_exit_lock
);
2220 spin_lock_irq(q
->queue_lock
);
2222 if (cfqd
->active_queue
)
2223 __cfq_slice_expired(cfqd
, cfqd
->active_queue
, 0);
2225 while (!list_empty(&cfqd
->cic_list
)) {
2226 struct cfq_io_context
*cic
= list_entry(cfqd
->cic_list
.next
,
2227 struct cfq_io_context
,
2229 if (cic
->cfqq
[ASYNC
]) {
2230 cfq_put_queue(cic
->cfqq
[ASYNC
]);
2231 cic
->cfqq
[ASYNC
] = NULL
;
2233 if (cic
->cfqq
[SYNC
]) {
2234 cfq_put_queue(cic
->cfqq
[SYNC
]);
2235 cic
->cfqq
[SYNC
] = NULL
;
2238 list_del_init(&cic
->queue_list
);
2241 spin_unlock_irq(q
->queue_lock
);
2242 spin_unlock(&cfq_exit_lock
);
2244 cfq_shutdown_timer_wq(cfqd
);
2246 mempool_destroy(cfqd
->crq_pool
);
2247 kfree(cfqd
->crq_hash
);
2248 kfree(cfqd
->cfq_hash
);
2252 static int cfq_init_queue(request_queue_t
*q
, elevator_t
*e
)
2254 struct cfq_data
*cfqd
;
2257 cfqd
= kmalloc(sizeof(*cfqd
), GFP_KERNEL
);
2261 memset(cfqd
, 0, sizeof(*cfqd
));
2263 for (i
= 0; i
< CFQ_PRIO_LISTS
; i
++)
2264 INIT_LIST_HEAD(&cfqd
->rr_list
[i
]);
2266 INIT_LIST_HEAD(&cfqd
->busy_rr
);
2267 INIT_LIST_HEAD(&cfqd
->cur_rr
);
2268 INIT_LIST_HEAD(&cfqd
->idle_rr
);
2269 INIT_LIST_HEAD(&cfqd
->empty_list
);
2270 INIT_LIST_HEAD(&cfqd
->cic_list
);
2272 cfqd
->crq_hash
= kmalloc(sizeof(struct hlist_head
) * CFQ_MHASH_ENTRIES
, GFP_KERNEL
);
2273 if (!cfqd
->crq_hash
)
2276 cfqd
->cfq_hash
= kmalloc(sizeof(struct hlist_head
) * CFQ_QHASH_ENTRIES
, GFP_KERNEL
);
2277 if (!cfqd
->cfq_hash
)
2280 cfqd
->crq_pool
= mempool_create_slab_pool(BLKDEV_MIN_RQ
, crq_pool
);
2281 if (!cfqd
->crq_pool
)
2284 for (i
= 0; i
< CFQ_MHASH_ENTRIES
; i
++)
2285 INIT_HLIST_HEAD(&cfqd
->crq_hash
[i
]);
2286 for (i
= 0; i
< CFQ_QHASH_ENTRIES
; i
++)
2287 INIT_HLIST_HEAD(&cfqd
->cfq_hash
[i
]);
2289 e
->elevator_data
= cfqd
;
2293 cfqd
->max_queued
= q
->nr_requests
/ 4;
2294 q
->nr_batching
= cfq_queued
;
2296 init_timer(&cfqd
->idle_slice_timer
);
2297 cfqd
->idle_slice_timer
.function
= cfq_idle_slice_timer
;
2298 cfqd
->idle_slice_timer
.data
= (unsigned long) cfqd
;
2300 init_timer(&cfqd
->idle_class_timer
);
2301 cfqd
->idle_class_timer
.function
= cfq_idle_class_timer
;
2302 cfqd
->idle_class_timer
.data
= (unsigned long) cfqd
;
2304 INIT_WORK(&cfqd
->unplug_work
, cfq_kick_queue
, q
);
2306 cfqd
->cfq_queued
= cfq_queued
;
2307 cfqd
->cfq_quantum
= cfq_quantum
;
2308 cfqd
->cfq_fifo_expire
[0] = cfq_fifo_expire
[0];
2309 cfqd
->cfq_fifo_expire
[1] = cfq_fifo_expire
[1];
2310 cfqd
->cfq_back_max
= cfq_back_max
;
2311 cfqd
->cfq_back_penalty
= cfq_back_penalty
;
2312 cfqd
->cfq_slice
[0] = cfq_slice_async
;
2313 cfqd
->cfq_slice
[1] = cfq_slice_sync
;
2314 cfqd
->cfq_slice_async_rq
= cfq_slice_async_rq
;
2315 cfqd
->cfq_slice_idle
= cfq_slice_idle
;
2319 kfree(cfqd
->cfq_hash
);
2321 kfree(cfqd
->crq_hash
);
2327 static void cfq_slab_kill(void)
2330 kmem_cache_destroy(crq_pool
);
2332 kmem_cache_destroy(cfq_pool
);
2334 kmem_cache_destroy(cfq_ioc_pool
);
2337 static int __init
cfq_slab_setup(void)
2339 crq_pool
= kmem_cache_create("crq_pool", sizeof(struct cfq_rq
), 0, 0,
2344 cfq_pool
= kmem_cache_create("cfq_pool", sizeof(struct cfq_queue
), 0, 0,
2349 cfq_ioc_pool
= kmem_cache_create("cfq_ioc_pool",
2350 sizeof(struct cfq_io_context
), 0, 0, NULL
, NULL
);
2361 * sysfs parts below -->
2365 cfq_var_show(unsigned int var
, char *page
)
2367 return sprintf(page
, "%d\n", var
);
2371 cfq_var_store(unsigned int *var
, const char *page
, size_t count
)
2373 char *p
= (char *) page
;
2375 *var
= simple_strtoul(p
, &p
, 10);
2379 #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \
2380 static ssize_t __FUNC(elevator_t *e, char *page) \
2382 struct cfq_data *cfqd = e->elevator_data; \
2383 unsigned int __data = __VAR; \
2385 __data = jiffies_to_msecs(__data); \
2386 return cfq_var_show(__data, (page)); \
2388 SHOW_FUNCTION(cfq_quantum_show
, cfqd
->cfq_quantum
, 0);
2389 SHOW_FUNCTION(cfq_queued_show
, cfqd
->cfq_queued
, 0);
2390 SHOW_FUNCTION(cfq_fifo_expire_sync_show
, cfqd
->cfq_fifo_expire
[1], 1);
2391 SHOW_FUNCTION(cfq_fifo_expire_async_show
, cfqd
->cfq_fifo_expire
[0], 1);
2392 SHOW_FUNCTION(cfq_back_seek_max_show
, cfqd
->cfq_back_max
, 0);
2393 SHOW_FUNCTION(cfq_back_seek_penalty_show
, cfqd
->cfq_back_penalty
, 0);
2394 SHOW_FUNCTION(cfq_slice_idle_show
, cfqd
->cfq_slice_idle
, 1);
2395 SHOW_FUNCTION(cfq_slice_sync_show
, cfqd
->cfq_slice
[1], 1);
2396 SHOW_FUNCTION(cfq_slice_async_show
, cfqd
->cfq_slice
[0], 1);
2397 SHOW_FUNCTION(cfq_slice_async_rq_show
, cfqd
->cfq_slice_async_rq
, 0);
2398 #undef SHOW_FUNCTION
2400 #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \
2401 static ssize_t __FUNC(elevator_t *e, const char *page, size_t count) \
2403 struct cfq_data *cfqd = e->elevator_data; \
2404 unsigned int __data; \
2405 int ret = cfq_var_store(&__data, (page), count); \
2406 if (__data < (MIN)) \
2408 else if (__data > (MAX)) \
2411 *(__PTR) = msecs_to_jiffies(__data); \
2413 *(__PTR) = __data; \
2416 STORE_FUNCTION(cfq_quantum_store
, &cfqd
->cfq_quantum
, 1, UINT_MAX
, 0);
2417 STORE_FUNCTION(cfq_queued_store
, &cfqd
->cfq_queued
, 1, UINT_MAX
, 0);
2418 STORE_FUNCTION(cfq_fifo_expire_sync_store
, &cfqd
->cfq_fifo_expire
[1], 1, UINT_MAX
, 1);
2419 STORE_FUNCTION(cfq_fifo_expire_async_store
, &cfqd
->cfq_fifo_expire
[0], 1, UINT_MAX
, 1);
2420 STORE_FUNCTION(cfq_back_seek_max_store
, &cfqd
->cfq_back_max
, 0, UINT_MAX
, 0);
2421 STORE_FUNCTION(cfq_back_seek_penalty_store
, &cfqd
->cfq_back_penalty
, 1, UINT_MAX
, 0);
2422 STORE_FUNCTION(cfq_slice_idle_store
, &cfqd
->cfq_slice_idle
, 0, UINT_MAX
, 1);
2423 STORE_FUNCTION(cfq_slice_sync_store
, &cfqd
->cfq_slice
[1], 1, UINT_MAX
, 1);
2424 STORE_FUNCTION(cfq_slice_async_store
, &cfqd
->cfq_slice
[0], 1, UINT_MAX
, 1);
2425 STORE_FUNCTION(cfq_slice_async_rq_store
, &cfqd
->cfq_slice_async_rq
, 1, UINT_MAX
, 0);
2426 #undef STORE_FUNCTION
2428 #define CFQ_ATTR(name) \
2429 __ATTR(name, S_IRUGO|S_IWUSR, cfq_##name##_show, cfq_##name##_store)
2431 static struct elv_fs_entry cfq_attrs
[] = {
2434 CFQ_ATTR(fifo_expire_sync
),
2435 CFQ_ATTR(fifo_expire_async
),
2436 CFQ_ATTR(back_seek_max
),
2437 CFQ_ATTR(back_seek_penalty
),
2438 CFQ_ATTR(slice_sync
),
2439 CFQ_ATTR(slice_async
),
2440 CFQ_ATTR(slice_async_rq
),
2441 CFQ_ATTR(slice_idle
),
2445 static struct elevator_type iosched_cfq
= {
2447 .elevator_merge_fn
= cfq_merge
,
2448 .elevator_merged_fn
= cfq_merged_request
,
2449 .elevator_merge_req_fn
= cfq_merged_requests
,
2450 .elevator_dispatch_fn
= cfq_dispatch_requests
,
2451 .elevator_add_req_fn
= cfq_insert_request
,
2452 .elevator_activate_req_fn
= cfq_activate_request
,
2453 .elevator_deactivate_req_fn
= cfq_deactivate_request
,
2454 .elevator_queue_empty_fn
= cfq_queue_empty
,
2455 .elevator_completed_req_fn
= cfq_completed_request
,
2456 .elevator_former_req_fn
= cfq_former_request
,
2457 .elevator_latter_req_fn
= cfq_latter_request
,
2458 .elevator_set_req_fn
= cfq_set_request
,
2459 .elevator_put_req_fn
= cfq_put_request
,
2460 .elevator_may_queue_fn
= cfq_may_queue
,
2461 .elevator_init_fn
= cfq_init_queue
,
2462 .elevator_exit_fn
= cfq_exit_queue
,
2465 .elevator_attrs
= cfq_attrs
,
2466 .elevator_name
= "cfq",
2467 .elevator_owner
= THIS_MODULE
,
2470 static int __init
cfq_init(void)
2475 * could be 0 on HZ < 1000 setups
2477 if (!cfq_slice_async
)
2478 cfq_slice_async
= 1;
2479 if (!cfq_slice_idle
)
2482 if (cfq_slab_setup())
2485 ret
= elv_register(&iosched_cfq
);
2492 static void __exit
cfq_exit(void)
2494 DECLARE_COMPLETION(all_gone
);
2495 elv_unregister(&iosched_cfq
);
2496 ioc_gone
= &all_gone
;
2497 /* ioc_gone's update must be visible before reading ioc_count */
2499 if (atomic_read(&ioc_count
))
2500 wait_for_completion(ioc_gone
);
2505 module_init(cfq_init
);
2506 module_exit(cfq_exit
);
2508 MODULE_AUTHOR("Jens Axboe");
2509 MODULE_LICENSE("GPL");
2510 MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler");