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@kernel.dk>
9 #include <linux/module.h>
10 #include <linux/slab.h>
11 #include <linux/blkdev.h>
12 #include <linux/elevator.h>
13 #include <linux/jiffies.h>
14 #include <linux/rbtree.h>
15 #include <linux/ioprio.h>
16 #include <linux/blktrace_api.h>
18 #include "blk-cgroup.h"
23 /* max queue in one round of service */
24 static const int cfq_quantum
= 8;
25 static const int cfq_fifo_expire
[2] = { HZ
/ 4, HZ
/ 8 };
26 /* maximum backwards seek, in KiB */
27 static const int cfq_back_max
= 16 * 1024;
28 /* penalty of a backwards seek */
29 static const int cfq_back_penalty
= 2;
30 static const int cfq_slice_sync
= HZ
/ 10;
31 static int cfq_slice_async
= HZ
/ 25;
32 static const int cfq_slice_async_rq
= 2;
33 static int cfq_slice_idle
= HZ
/ 125;
34 static int cfq_group_idle
= HZ
/ 125;
35 static const int cfq_target_latency
= HZ
* 3/10; /* 300 ms */
36 static const int cfq_hist_divisor
= 4;
39 * offset from end of service tree
41 #define CFQ_IDLE_DELAY (HZ / 5)
44 * below this threshold, we consider thinktime immediate
46 #define CFQ_MIN_TT (2)
48 #define CFQ_SLICE_SCALE (5)
49 #define CFQ_HW_QUEUE_MIN (5)
50 #define CFQ_SERVICE_SHIFT 12
52 #define CFQQ_SEEK_THR (sector_t)(8 * 100)
53 #define CFQQ_CLOSE_THR (sector_t)(8 * 1024)
54 #define CFQQ_SECT_THR_NONROT (sector_t)(2 * 32)
55 #define CFQQ_SEEKY(cfqq) (hweight32(cfqq->seek_history) > 32/8)
57 #define RQ_CIC(rq) icq_to_cic((rq)->elv.icq)
58 #define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elv.priv[0])
59 #define RQ_CFQG(rq) (struct cfq_group *) ((rq)->elv.priv[1])
61 static struct kmem_cache
*cfq_pool
;
63 #define CFQ_PRIO_LISTS IOPRIO_BE_NR
64 #define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE)
65 #define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT)
67 #define sample_valid(samples) ((samples) > 80)
68 #define rb_entry_cfqg(node) rb_entry((node), struct cfq_group, rb_node)
71 unsigned long last_end_request
;
73 unsigned long ttime_total
;
74 unsigned long ttime_samples
;
75 unsigned long ttime_mean
;
79 * Most of our rbtree usage is for sorting with min extraction, so
80 * if we cache the leftmost node we don't have to walk down the tree
81 * to find it. Idea borrowed from Ingo Molnars CFS scheduler. We should
82 * move this into the elevator for the rq sorting as well.
88 unsigned total_weight
;
90 struct cfq_ttime ttime
;
92 #define CFQ_RB_ROOT (struct cfq_rb_root) { .rb = RB_ROOT, \
93 .ttime = {.last_end_request = jiffies,},}
96 * Per process-grouping structure
101 /* various state flags, see below */
103 /* parent cfq_data */
104 struct cfq_data
*cfqd
;
105 /* service_tree member */
106 struct rb_node rb_node
;
107 /* service_tree key */
108 unsigned long rb_key
;
109 /* prio tree member */
110 struct rb_node p_node
;
111 /* prio tree root we belong to, if any */
112 struct rb_root
*p_root
;
113 /* sorted list of pending requests */
114 struct rb_root sort_list
;
115 /* if fifo isn't expired, next request to serve */
116 struct request
*next_rq
;
117 /* requests queued in sort_list */
119 /* currently allocated requests */
121 /* fifo list of requests in sort_list */
122 struct list_head fifo
;
124 /* time when queue got scheduled in to dispatch first request. */
125 unsigned long dispatch_start
;
126 unsigned int allocated_slice
;
127 unsigned int slice_dispatch
;
128 /* time when first request from queue completed and slice started. */
129 unsigned long slice_start
;
130 unsigned long slice_end
;
133 /* pending priority requests */
135 /* number of requests that are on the dispatch list or inside driver */
138 /* io prio of this group */
139 unsigned short ioprio
, org_ioprio
;
140 unsigned short ioprio_class
;
145 sector_t last_request_pos
;
147 struct cfq_rb_root
*service_tree
;
148 struct cfq_queue
*new_cfqq
;
149 struct cfq_group
*cfqg
;
150 /* Number of sectors dispatched from queue in single dispatch round */
151 unsigned long nr_sectors
;
155 * First index in the service_trees.
156 * IDLE is handled separately, so it has negative index
166 * Second index in the service_trees.
170 SYNC_NOIDLE_WORKLOAD
= 1,
175 #ifdef CONFIG_CFQ_GROUP_IOSCHED
176 /* total bytes transferred */
177 struct blkg_rwstat service_bytes
;
178 /* total IOs serviced, post merge */
179 struct blkg_rwstat serviced
;
180 /* number of ios merged */
181 struct blkg_rwstat merged
;
182 /* total time spent on device in ns, may not be accurate w/ queueing */
183 struct blkg_rwstat service_time
;
184 /* total time spent waiting in scheduler queue in ns */
185 struct blkg_rwstat wait_time
;
186 /* number of IOs queued up */
187 struct blkg_rwstat queued
;
188 /* total sectors transferred */
189 struct blkg_stat sectors
;
190 /* total disk time and nr sectors dispatched by this group */
191 struct blkg_stat time
;
192 #ifdef CONFIG_DEBUG_BLK_CGROUP
193 /* time not charged to this cgroup */
194 struct blkg_stat unaccounted_time
;
195 /* sum of number of ios queued across all samples */
196 struct blkg_stat avg_queue_size_sum
;
197 /* count of samples taken for average */
198 struct blkg_stat avg_queue_size_samples
;
199 /* how many times this group has been removed from service tree */
200 struct blkg_stat dequeue
;
201 /* total time spent waiting for it to be assigned a timeslice. */
202 struct blkg_stat group_wait_time
;
203 /* time spent idling for this blkcg_gq */
204 struct blkg_stat idle_time
;
205 /* total time with empty current active q with other requests queued */
206 struct blkg_stat empty_time
;
207 /* fields after this shouldn't be cleared on stat reset */
208 uint64_t start_group_wait_time
;
209 uint64_t start_idle_time
;
210 uint64_t start_empty_time
;
212 #endif /* CONFIG_DEBUG_BLK_CGROUP */
213 #endif /* CONFIG_CFQ_GROUP_IOSCHED */
216 /* This is per cgroup per device grouping structure */
218 /* must be the first member */
219 struct blkg_policy_data pd
;
221 /* group service_tree member */
222 struct rb_node rb_node
;
224 /* group service_tree key */
228 * There are two weights - (internal) weight is the weight of this
229 * cfqg against the sibling cfqgs. leaf_weight is the wight of
230 * this cfqg against the child cfqgs. For the root cfqg, both
231 * weights are kept in sync for backward compatibility.
234 unsigned int new_weight
;
235 unsigned int dev_weight
;
237 unsigned int leaf_weight
;
238 unsigned int new_leaf_weight
;
239 unsigned int dev_leaf_weight
;
241 /* number of cfqq currently on this group */
245 * Per group busy queues average. Useful for workload slice calc. We
246 * create the array for each prio class but at run time it is used
247 * only for RT and BE class and slot for IDLE class remains unused.
248 * This is primarily done to avoid confusion and a gcc warning.
250 unsigned int busy_queues_avg
[CFQ_PRIO_NR
];
252 * rr lists of queues with requests. We maintain service trees for
253 * RT and BE classes. These trees are subdivided in subclasses
254 * of SYNC, SYNC_NOIDLE and ASYNC based on workload type. For IDLE
255 * class there is no subclassification and all the cfq queues go on
256 * a single tree service_tree_idle.
257 * Counts are embedded in the cfq_rb_root
259 struct cfq_rb_root service_trees
[2][3];
260 struct cfq_rb_root service_tree_idle
;
262 unsigned long saved_wl_slice
;
263 enum wl_type_t saved_wl_type
;
264 enum wl_class_t saved_wl_class
;
266 /* number of requests that are on the dispatch list or inside driver */
268 struct cfq_ttime ttime
;
269 struct cfqg_stats stats
;
273 struct io_cq icq
; /* must be the first member */
274 struct cfq_queue
*cfqq
[2];
275 struct cfq_ttime ttime
;
276 int ioprio
; /* the current ioprio */
277 #ifdef CONFIG_CFQ_GROUP_IOSCHED
278 uint64_t blkcg_id
; /* the current blkcg ID */
283 * Per block device queue structure
286 struct request_queue
*queue
;
287 /* Root service tree for cfq_groups */
288 struct cfq_rb_root grp_service_tree
;
289 struct cfq_group
*root_group
;
292 * The priority currently being served
294 enum wl_class_t serving_wl_class
;
295 enum wl_type_t serving_wl_type
;
296 unsigned long workload_expires
;
297 struct cfq_group
*serving_group
;
300 * Each priority tree is sorted by next_request position. These
301 * trees are used when determining if two or more queues are
302 * interleaving requests (see cfq_close_cooperator).
304 struct rb_root prio_trees
[CFQ_PRIO_LISTS
];
306 unsigned int busy_queues
;
307 unsigned int busy_sync_queues
;
313 * queue-depth detection
319 * -1 => indeterminate, (cfq will behave as if NCQ is present, to allow better detection)
320 * 1 => NCQ is present (hw_tag_est_depth is the estimated max depth)
323 int hw_tag_est_depth
;
324 unsigned int hw_tag_samples
;
327 * idle window management
329 struct timer_list idle_slice_timer
;
330 struct work_struct unplug_work
;
332 struct cfq_queue
*active_queue
;
333 struct cfq_io_cq
*active_cic
;
336 * async queue for each priority case
338 struct cfq_queue
*async_cfqq
[2][IOPRIO_BE_NR
];
339 struct cfq_queue
*async_idle_cfqq
;
341 sector_t last_position
;
344 * tunables, see top of file
346 unsigned int cfq_quantum
;
347 unsigned int cfq_fifo_expire
[2];
348 unsigned int cfq_back_penalty
;
349 unsigned int cfq_back_max
;
350 unsigned int cfq_slice
[2];
351 unsigned int cfq_slice_async_rq
;
352 unsigned int cfq_slice_idle
;
353 unsigned int cfq_group_idle
;
354 unsigned int cfq_latency
;
355 unsigned int cfq_target_latency
;
358 * Fallback dummy cfqq for extreme OOM conditions
360 struct cfq_queue oom_cfqq
;
362 unsigned long last_delayed_sync
;
365 static struct cfq_group
*cfq_get_next_cfqg(struct cfq_data
*cfqd
);
367 static struct cfq_rb_root
*st_for(struct cfq_group
*cfqg
,
368 enum wl_class_t
class,
374 if (class == IDLE_WORKLOAD
)
375 return &cfqg
->service_tree_idle
;
377 return &cfqg
->service_trees
[class][type
];
380 enum cfqq_state_flags
{
381 CFQ_CFQQ_FLAG_on_rr
= 0, /* on round-robin busy list */
382 CFQ_CFQQ_FLAG_wait_request
, /* waiting for a request */
383 CFQ_CFQQ_FLAG_must_dispatch
, /* must be allowed a dispatch */
384 CFQ_CFQQ_FLAG_must_alloc_slice
, /* per-slice must_alloc flag */
385 CFQ_CFQQ_FLAG_fifo_expire
, /* FIFO checked in this slice */
386 CFQ_CFQQ_FLAG_idle_window
, /* slice idling enabled */
387 CFQ_CFQQ_FLAG_prio_changed
, /* task priority has changed */
388 CFQ_CFQQ_FLAG_slice_new
, /* no requests dispatched in slice */
389 CFQ_CFQQ_FLAG_sync
, /* synchronous queue */
390 CFQ_CFQQ_FLAG_coop
, /* cfqq is shared */
391 CFQ_CFQQ_FLAG_split_coop
, /* shared cfqq will be splitted */
392 CFQ_CFQQ_FLAG_deep
, /* sync cfqq experienced large depth */
393 CFQ_CFQQ_FLAG_wait_busy
, /* Waiting for next request */
396 #define CFQ_CFQQ_FNS(name) \
397 static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \
399 (cfqq)->flags |= (1 << CFQ_CFQQ_FLAG_##name); \
401 static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \
403 (cfqq)->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \
405 static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \
407 return ((cfqq)->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \
411 CFQ_CFQQ_FNS(wait_request
);
412 CFQ_CFQQ_FNS(must_dispatch
);
413 CFQ_CFQQ_FNS(must_alloc_slice
);
414 CFQ_CFQQ_FNS(fifo_expire
);
415 CFQ_CFQQ_FNS(idle_window
);
416 CFQ_CFQQ_FNS(prio_changed
);
417 CFQ_CFQQ_FNS(slice_new
);
420 CFQ_CFQQ_FNS(split_coop
);
422 CFQ_CFQQ_FNS(wait_busy
);
425 static inline struct cfq_group
*pd_to_cfqg(struct blkg_policy_data
*pd
)
427 return pd
? container_of(pd
, struct cfq_group
, pd
) : NULL
;
430 static inline struct blkcg_gq
*cfqg_to_blkg(struct cfq_group
*cfqg
)
432 return pd_to_blkg(&cfqg
->pd
);
435 #if defined(CONFIG_CFQ_GROUP_IOSCHED) && defined(CONFIG_DEBUG_BLK_CGROUP)
437 /* cfqg stats flags */
438 enum cfqg_stats_flags
{
439 CFQG_stats_waiting
= 0,
444 #define CFQG_FLAG_FNS(name) \
445 static inline void cfqg_stats_mark_##name(struct cfqg_stats *stats) \
447 stats->flags |= (1 << CFQG_stats_##name); \
449 static inline void cfqg_stats_clear_##name(struct cfqg_stats *stats) \
451 stats->flags &= ~(1 << CFQG_stats_##name); \
453 static inline int cfqg_stats_##name(struct cfqg_stats *stats) \
455 return (stats->flags & (1 << CFQG_stats_##name)) != 0; \
458 CFQG_FLAG_FNS(waiting)
459 CFQG_FLAG_FNS(idling
)
463 /* This should be called with the queue_lock held. */
464 static void cfqg_stats_update_group_wait_time(struct cfqg_stats
*stats
)
466 unsigned long long now
;
468 if (!cfqg_stats_waiting(stats
))
472 if (time_after64(now
, stats
->start_group_wait_time
))
473 blkg_stat_add(&stats
->group_wait_time
,
474 now
- stats
->start_group_wait_time
);
475 cfqg_stats_clear_waiting(stats
);
478 /* This should be called with the queue_lock held. */
479 static void cfqg_stats_set_start_group_wait_time(struct cfq_group
*cfqg
,
480 struct cfq_group
*curr_cfqg
)
482 struct cfqg_stats
*stats
= &cfqg
->stats
;
484 if (cfqg_stats_waiting(stats
))
486 if (cfqg
== curr_cfqg
)
488 stats
->start_group_wait_time
= sched_clock();
489 cfqg_stats_mark_waiting(stats
);
492 /* This should be called with the queue_lock held. */
493 static void cfqg_stats_end_empty_time(struct cfqg_stats
*stats
)
495 unsigned long long now
;
497 if (!cfqg_stats_empty(stats
))
501 if (time_after64(now
, stats
->start_empty_time
))
502 blkg_stat_add(&stats
->empty_time
,
503 now
- stats
->start_empty_time
);
504 cfqg_stats_clear_empty(stats
);
507 static void cfqg_stats_update_dequeue(struct cfq_group
*cfqg
)
509 blkg_stat_add(&cfqg
->stats
.dequeue
, 1);
512 static void cfqg_stats_set_start_empty_time(struct cfq_group
*cfqg
)
514 struct cfqg_stats
*stats
= &cfqg
->stats
;
516 if (blkg_rwstat_sum(&stats
->queued
))
520 * group is already marked empty. This can happen if cfqq got new
521 * request in parent group and moved to this group while being added
522 * to service tree. Just ignore the event and move on.
524 if (cfqg_stats_empty(stats
))
527 stats
->start_empty_time
= sched_clock();
528 cfqg_stats_mark_empty(stats
);
531 static void cfqg_stats_update_idle_time(struct cfq_group
*cfqg
)
533 struct cfqg_stats
*stats
= &cfqg
->stats
;
535 if (cfqg_stats_idling(stats
)) {
536 unsigned long long now
= sched_clock();
538 if (time_after64(now
, stats
->start_idle_time
))
539 blkg_stat_add(&stats
->idle_time
,
540 now
- stats
->start_idle_time
);
541 cfqg_stats_clear_idling(stats
);
545 static void cfqg_stats_set_start_idle_time(struct cfq_group
*cfqg
)
547 struct cfqg_stats
*stats
= &cfqg
->stats
;
549 BUG_ON(cfqg_stats_idling(stats
));
551 stats
->start_idle_time
= sched_clock();
552 cfqg_stats_mark_idling(stats
);
555 static void cfqg_stats_update_avg_queue_size(struct cfq_group
*cfqg
)
557 struct cfqg_stats
*stats
= &cfqg
->stats
;
559 blkg_stat_add(&stats
->avg_queue_size_sum
,
560 blkg_rwstat_sum(&stats
->queued
));
561 blkg_stat_add(&stats
->avg_queue_size_samples
, 1);
562 cfqg_stats_update_group_wait_time(stats
);
565 #else /* CONFIG_CFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */
567 static inline void cfqg_stats_set_start_group_wait_time(struct cfq_group
*cfqg
, struct cfq_group
*curr_cfqg
) { }
568 static inline void cfqg_stats_end_empty_time(struct cfqg_stats
*stats
) { }
569 static inline void cfqg_stats_update_dequeue(struct cfq_group
*cfqg
) { }
570 static inline void cfqg_stats_set_start_empty_time(struct cfq_group
*cfqg
) { }
571 static inline void cfqg_stats_update_idle_time(struct cfq_group
*cfqg
) { }
572 static inline void cfqg_stats_set_start_idle_time(struct cfq_group
*cfqg
) { }
573 static inline void cfqg_stats_update_avg_queue_size(struct cfq_group
*cfqg
) { }
575 #endif /* CONFIG_CFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */
577 #ifdef CONFIG_CFQ_GROUP_IOSCHED
579 static struct blkcg_policy blkcg_policy_cfq
;
581 static inline struct cfq_group
*blkg_to_cfqg(struct blkcg_gq
*blkg
)
583 return pd_to_cfqg(blkg_to_pd(blkg
, &blkcg_policy_cfq
));
586 static inline void cfqg_get(struct cfq_group
*cfqg
)
588 return blkg_get(cfqg_to_blkg(cfqg
));
591 static inline void cfqg_put(struct cfq_group
*cfqg
)
593 return blkg_put(cfqg_to_blkg(cfqg
));
596 #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) do { \
599 blkg_path(cfqg_to_blkg((cfqq)->cfqg), __pbuf, sizeof(__pbuf)); \
600 blk_add_trace_msg((cfqd)->queue, "cfq%d%c%c %s " fmt, (cfqq)->pid, \
601 cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \
602 cfqq_type((cfqq)) == SYNC_NOIDLE_WORKLOAD ? 'N' : ' ',\
606 #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) do { \
609 blkg_path(cfqg_to_blkg(cfqg), __pbuf, sizeof(__pbuf)); \
610 blk_add_trace_msg((cfqd)->queue, "%s " fmt, __pbuf, ##args); \
613 static inline void cfqg_stats_update_io_add(struct cfq_group
*cfqg
,
614 struct cfq_group
*curr_cfqg
, int rw
)
616 blkg_rwstat_add(&cfqg
->stats
.queued
, rw
, 1);
617 cfqg_stats_end_empty_time(&cfqg
->stats
);
618 cfqg_stats_set_start_group_wait_time(cfqg
, curr_cfqg
);
621 static inline void cfqg_stats_update_timeslice_used(struct cfq_group
*cfqg
,
622 unsigned long time
, unsigned long unaccounted_time
)
624 blkg_stat_add(&cfqg
->stats
.time
, time
);
625 #ifdef CONFIG_DEBUG_BLK_CGROUP
626 blkg_stat_add(&cfqg
->stats
.unaccounted_time
, unaccounted_time
);
630 static inline void cfqg_stats_update_io_remove(struct cfq_group
*cfqg
, int rw
)
632 blkg_rwstat_add(&cfqg
->stats
.queued
, rw
, -1);
635 static inline void cfqg_stats_update_io_merged(struct cfq_group
*cfqg
, int rw
)
637 blkg_rwstat_add(&cfqg
->stats
.merged
, rw
, 1);
640 static inline void cfqg_stats_update_dispatch(struct cfq_group
*cfqg
,
641 uint64_t bytes
, int rw
)
643 blkg_stat_add(&cfqg
->stats
.sectors
, bytes
>> 9);
644 blkg_rwstat_add(&cfqg
->stats
.serviced
, rw
, 1);
645 blkg_rwstat_add(&cfqg
->stats
.service_bytes
, rw
, bytes
);
648 static inline void cfqg_stats_update_completion(struct cfq_group
*cfqg
,
649 uint64_t start_time
, uint64_t io_start_time
, int rw
)
651 struct cfqg_stats
*stats
= &cfqg
->stats
;
652 unsigned long long now
= sched_clock();
654 if (time_after64(now
, io_start_time
))
655 blkg_rwstat_add(&stats
->service_time
, rw
, now
- io_start_time
);
656 if (time_after64(io_start_time
, start_time
))
657 blkg_rwstat_add(&stats
->wait_time
, rw
,
658 io_start_time
- start_time
);
661 static void cfq_pd_reset_stats(struct blkcg_gq
*blkg
)
663 struct cfq_group
*cfqg
= blkg_to_cfqg(blkg
);
664 struct cfqg_stats
*stats
= &cfqg
->stats
;
666 /* queued stats shouldn't be cleared */
667 blkg_rwstat_reset(&stats
->service_bytes
);
668 blkg_rwstat_reset(&stats
->serviced
);
669 blkg_rwstat_reset(&stats
->merged
);
670 blkg_rwstat_reset(&stats
->service_time
);
671 blkg_rwstat_reset(&stats
->wait_time
);
672 blkg_stat_reset(&stats
->time
);
673 #ifdef CONFIG_DEBUG_BLK_CGROUP
674 blkg_stat_reset(&stats
->unaccounted_time
);
675 blkg_stat_reset(&stats
->avg_queue_size_sum
);
676 blkg_stat_reset(&stats
->avg_queue_size_samples
);
677 blkg_stat_reset(&stats
->dequeue
);
678 blkg_stat_reset(&stats
->group_wait_time
);
679 blkg_stat_reset(&stats
->idle_time
);
680 blkg_stat_reset(&stats
->empty_time
);
684 #else /* CONFIG_CFQ_GROUP_IOSCHED */
686 static inline void cfqg_get(struct cfq_group
*cfqg
) { }
687 static inline void cfqg_put(struct cfq_group
*cfqg
) { }
689 #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \
690 blk_add_trace_msg((cfqd)->queue, "cfq%d%c%c " fmt, (cfqq)->pid, \
691 cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \
692 cfqq_type((cfqq)) == SYNC_NOIDLE_WORKLOAD ? 'N' : ' ',\
694 #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) do {} while (0)
696 static inline void cfqg_stats_update_io_add(struct cfq_group
*cfqg
,
697 struct cfq_group
*curr_cfqg
, int rw
) { }
698 static inline void cfqg_stats_update_timeslice_used(struct cfq_group
*cfqg
,
699 unsigned long time
, unsigned long unaccounted_time
) { }
700 static inline void cfqg_stats_update_io_remove(struct cfq_group
*cfqg
, int rw
) { }
701 static inline void cfqg_stats_update_io_merged(struct cfq_group
*cfqg
, int rw
) { }
702 static inline void cfqg_stats_update_dispatch(struct cfq_group
*cfqg
,
703 uint64_t bytes
, int rw
) { }
704 static inline void cfqg_stats_update_completion(struct cfq_group
*cfqg
,
705 uint64_t start_time
, uint64_t io_start_time
, int rw
) { }
707 #endif /* CONFIG_CFQ_GROUP_IOSCHED */
709 #define cfq_log(cfqd, fmt, args...) \
710 blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args)
712 /* Traverses through cfq group service trees */
713 #define for_each_cfqg_st(cfqg, i, j, st) \
714 for (i = 0; i <= IDLE_WORKLOAD; i++) \
715 for (j = 0, st = i < IDLE_WORKLOAD ? &cfqg->service_trees[i][j]\
716 : &cfqg->service_tree_idle; \
717 (i < IDLE_WORKLOAD && j <= SYNC_WORKLOAD) || \
718 (i == IDLE_WORKLOAD && j == 0); \
719 j++, st = i < IDLE_WORKLOAD ? \
720 &cfqg->service_trees[i][j]: NULL) \
722 static inline bool cfq_io_thinktime_big(struct cfq_data *cfqd,
723 struct cfq_ttime
*ttime
, bool group_idle
)
726 if (!sample_valid(ttime
->ttime_samples
))
729 slice
= cfqd
->cfq_group_idle
;
731 slice
= cfqd
->cfq_slice_idle
;
732 return ttime
->ttime_mean
> slice
;
735 static inline bool iops_mode(struct cfq_data
*cfqd
)
738 * If we are not idling on queues and it is a NCQ drive, parallel
739 * execution of requests is on and measuring time is not possible
740 * in most of the cases until and unless we drive shallower queue
741 * depths and that becomes a performance bottleneck. In such cases
742 * switch to start providing fairness in terms of number of IOs.
744 if (!cfqd
->cfq_slice_idle
&& cfqd
->hw_tag
)
750 static inline enum wl_class_t
cfqq_class(struct cfq_queue
*cfqq
)
752 if (cfq_class_idle(cfqq
))
753 return IDLE_WORKLOAD
;
754 if (cfq_class_rt(cfqq
))
760 static enum wl_type_t
cfqq_type(struct cfq_queue
*cfqq
)
762 if (!cfq_cfqq_sync(cfqq
))
763 return ASYNC_WORKLOAD
;
764 if (!cfq_cfqq_idle_window(cfqq
))
765 return SYNC_NOIDLE_WORKLOAD
;
766 return SYNC_WORKLOAD
;
769 static inline int cfq_group_busy_queues_wl(enum wl_class_t wl_class
,
770 struct cfq_data
*cfqd
,
771 struct cfq_group
*cfqg
)
773 if (wl_class
== IDLE_WORKLOAD
)
774 return cfqg
->service_tree_idle
.count
;
776 return cfqg
->service_trees
[wl_class
][ASYNC_WORKLOAD
].count
+
777 cfqg
->service_trees
[wl_class
][SYNC_NOIDLE_WORKLOAD
].count
+
778 cfqg
->service_trees
[wl_class
][SYNC_WORKLOAD
].count
;
781 static inline int cfqg_busy_async_queues(struct cfq_data
*cfqd
,
782 struct cfq_group
*cfqg
)
784 return cfqg
->service_trees
[RT_WORKLOAD
][ASYNC_WORKLOAD
].count
+
785 cfqg
->service_trees
[BE_WORKLOAD
][ASYNC_WORKLOAD
].count
;
788 static void cfq_dispatch_insert(struct request_queue
*, struct request
*);
789 static struct cfq_queue
*cfq_get_queue(struct cfq_data
*cfqd
, bool is_sync
,
790 struct cfq_io_cq
*cic
, struct bio
*bio
,
793 static inline struct cfq_io_cq
*icq_to_cic(struct io_cq
*icq
)
795 /* cic->icq is the first member, %NULL will convert to %NULL */
796 return container_of(icq
, struct cfq_io_cq
, icq
);
799 static inline struct cfq_io_cq
*cfq_cic_lookup(struct cfq_data
*cfqd
,
800 struct io_context
*ioc
)
803 return icq_to_cic(ioc_lookup_icq(ioc
, cfqd
->queue
));
807 static inline struct cfq_queue
*cic_to_cfqq(struct cfq_io_cq
*cic
, bool is_sync
)
809 return cic
->cfqq
[is_sync
];
812 static inline void cic_set_cfqq(struct cfq_io_cq
*cic
, struct cfq_queue
*cfqq
,
815 cic
->cfqq
[is_sync
] = cfqq
;
818 static inline struct cfq_data
*cic_to_cfqd(struct cfq_io_cq
*cic
)
820 return cic
->icq
.q
->elevator
->elevator_data
;
824 * We regard a request as SYNC, if it's either a read or has the SYNC bit
825 * set (in which case it could also be direct WRITE).
827 static inline bool cfq_bio_sync(struct bio
*bio
)
829 return bio_data_dir(bio
) == READ
|| (bio
->bi_rw
& REQ_SYNC
);
833 * scheduler run of queue, if there are requests pending and no one in the
834 * driver that will restart queueing
836 static inline void cfq_schedule_dispatch(struct cfq_data
*cfqd
)
838 if (cfqd
->busy_queues
) {
839 cfq_log(cfqd
, "schedule dispatch");
840 kblockd_schedule_work(cfqd
->queue
, &cfqd
->unplug_work
);
845 * Scale schedule slice based on io priority. Use the sync time slice only
846 * if a queue is marked sync and has sync io queued. A sync queue with async
847 * io only, should not get full sync slice length.
849 static inline int cfq_prio_slice(struct cfq_data
*cfqd
, bool sync
,
852 const int base_slice
= cfqd
->cfq_slice
[sync
];
854 WARN_ON(prio
>= IOPRIO_BE_NR
);
856 return base_slice
+ (base_slice
/CFQ_SLICE_SCALE
* (4 - prio
));
860 cfq_prio_to_slice(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
862 return cfq_prio_slice(cfqd
, cfq_cfqq_sync(cfqq
), cfqq
->ioprio
);
865 static inline u64
cfq_scale_slice(unsigned long delta
, struct cfq_group
*cfqg
)
867 u64 d
= delta
<< CFQ_SERVICE_SHIFT
;
869 d
= d
* CFQ_WEIGHT_DEFAULT
;
870 do_div(d
, cfqg
->weight
);
874 static inline u64
max_vdisktime(u64 min_vdisktime
, u64 vdisktime
)
876 s64 delta
= (s64
)(vdisktime
- min_vdisktime
);
878 min_vdisktime
= vdisktime
;
880 return min_vdisktime
;
883 static inline u64
min_vdisktime(u64 min_vdisktime
, u64 vdisktime
)
885 s64 delta
= (s64
)(vdisktime
- min_vdisktime
);
887 min_vdisktime
= vdisktime
;
889 return min_vdisktime
;
892 static void update_min_vdisktime(struct cfq_rb_root
*st
)
894 struct cfq_group
*cfqg
;
897 cfqg
= rb_entry_cfqg(st
->left
);
898 st
->min_vdisktime
= max_vdisktime(st
->min_vdisktime
,
904 * get averaged number of queues of RT/BE priority.
905 * average is updated, with a formula that gives more weight to higher numbers,
906 * to quickly follows sudden increases and decrease slowly
909 static inline unsigned cfq_group_get_avg_queues(struct cfq_data
*cfqd
,
910 struct cfq_group
*cfqg
, bool rt
)
912 unsigned min_q
, max_q
;
913 unsigned mult
= cfq_hist_divisor
- 1;
914 unsigned round
= cfq_hist_divisor
/ 2;
915 unsigned busy
= cfq_group_busy_queues_wl(rt
, cfqd
, cfqg
);
917 min_q
= min(cfqg
->busy_queues_avg
[rt
], busy
);
918 max_q
= max(cfqg
->busy_queues_avg
[rt
], busy
);
919 cfqg
->busy_queues_avg
[rt
] = (mult
* max_q
+ min_q
+ round
) /
921 return cfqg
->busy_queues_avg
[rt
];
924 static inline unsigned
925 cfq_group_slice(struct cfq_data
*cfqd
, struct cfq_group
*cfqg
)
927 struct cfq_rb_root
*st
= &cfqd
->grp_service_tree
;
929 return cfqd
->cfq_target_latency
* cfqg
->weight
/ st
->total_weight
;
932 static inline unsigned
933 cfq_scaled_cfqq_slice(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
935 unsigned slice
= cfq_prio_to_slice(cfqd
, cfqq
);
936 if (cfqd
->cfq_latency
) {
938 * interested queues (we consider only the ones with the same
939 * priority class in the cfq group)
941 unsigned iq
= cfq_group_get_avg_queues(cfqd
, cfqq
->cfqg
,
943 unsigned sync_slice
= cfqd
->cfq_slice
[1];
944 unsigned expect_latency
= sync_slice
* iq
;
945 unsigned group_slice
= cfq_group_slice(cfqd
, cfqq
->cfqg
);
947 if (expect_latency
> group_slice
) {
948 unsigned base_low_slice
= 2 * cfqd
->cfq_slice_idle
;
949 /* scale low_slice according to IO priority
950 * and sync vs async */
952 min(slice
, base_low_slice
* slice
/ sync_slice
);
953 /* the adapted slice value is scaled to fit all iqs
954 * into the target latency */
955 slice
= max(slice
* group_slice
/ expect_latency
,
963 cfq_set_prio_slice(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
965 unsigned slice
= cfq_scaled_cfqq_slice(cfqd
, cfqq
);
967 cfqq
->slice_start
= jiffies
;
968 cfqq
->slice_end
= jiffies
+ slice
;
969 cfqq
->allocated_slice
= slice
;
970 cfq_log_cfqq(cfqd
, cfqq
, "set_slice=%lu", cfqq
->slice_end
- jiffies
);
974 * We need to wrap this check in cfq_cfqq_slice_new(), since ->slice_end
975 * isn't valid until the first request from the dispatch is activated
976 * and the slice time set.
978 static inline bool cfq_slice_used(struct cfq_queue
*cfqq
)
980 if (cfq_cfqq_slice_new(cfqq
))
982 if (time_before(jiffies
, cfqq
->slice_end
))
989 * Lifted from AS - choose which of rq1 and rq2 that is best served now.
990 * We choose the request that is closest to the head right now. Distance
991 * behind the head is penalized and only allowed to a certain extent.
993 static struct request
*
994 cfq_choose_req(struct cfq_data
*cfqd
, struct request
*rq1
, struct request
*rq2
, sector_t last
)
996 sector_t s1
, s2
, d1
= 0, d2
= 0;
997 unsigned long back_max
;
998 #define CFQ_RQ1_WRAP 0x01 /* request 1 wraps */
999 #define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */
1000 unsigned wrap
= 0; /* bit mask: requests behind the disk head? */
1002 if (rq1
== NULL
|| rq1
== rq2
)
1007 if (rq_is_sync(rq1
) != rq_is_sync(rq2
))
1008 return rq_is_sync(rq1
) ? rq1
: rq2
;
1010 if ((rq1
->cmd_flags
^ rq2
->cmd_flags
) & REQ_PRIO
)
1011 return rq1
->cmd_flags
& REQ_PRIO
? rq1
: rq2
;
1013 s1
= blk_rq_pos(rq1
);
1014 s2
= blk_rq_pos(rq2
);
1017 * by definition, 1KiB is 2 sectors
1019 back_max
= cfqd
->cfq_back_max
* 2;
1022 * Strict one way elevator _except_ in the case where we allow
1023 * short backward seeks which are biased as twice the cost of a
1024 * similar forward seek.
1028 else if (s1
+ back_max
>= last
)
1029 d1
= (last
- s1
) * cfqd
->cfq_back_penalty
;
1031 wrap
|= CFQ_RQ1_WRAP
;
1035 else if (s2
+ back_max
>= last
)
1036 d2
= (last
- s2
) * cfqd
->cfq_back_penalty
;
1038 wrap
|= CFQ_RQ2_WRAP
;
1040 /* Found required data */
1043 * By doing switch() on the bit mask "wrap" we avoid having to
1044 * check two variables for all permutations: --> faster!
1047 case 0: /* common case for CFQ: rq1 and rq2 not wrapped */
1063 case (CFQ_RQ1_WRAP
|CFQ_RQ2_WRAP
): /* both rqs wrapped */
1066 * Since both rqs are wrapped,
1067 * start with the one that's further behind head
1068 * (--> only *one* back seek required),
1069 * since back seek takes more time than forward.
1079 * The below is leftmost cache rbtree addon
1081 static struct cfq_queue
*cfq_rb_first(struct cfq_rb_root
*root
)
1083 /* Service tree is empty */
1088 root
->left
= rb_first(&root
->rb
);
1091 return rb_entry(root
->left
, struct cfq_queue
, rb_node
);
1096 static struct cfq_group
*cfq_rb_first_group(struct cfq_rb_root
*root
)
1099 root
->left
= rb_first(&root
->rb
);
1102 return rb_entry_cfqg(root
->left
);
1107 static void rb_erase_init(struct rb_node
*n
, struct rb_root
*root
)
1113 static void cfq_rb_erase(struct rb_node
*n
, struct cfq_rb_root
*root
)
1115 if (root
->left
== n
)
1117 rb_erase_init(n
, &root
->rb
);
1122 * would be nice to take fifo expire time into account as well
1124 static struct request
*
1125 cfq_find_next_rq(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
1126 struct request
*last
)
1128 struct rb_node
*rbnext
= rb_next(&last
->rb_node
);
1129 struct rb_node
*rbprev
= rb_prev(&last
->rb_node
);
1130 struct request
*next
= NULL
, *prev
= NULL
;
1132 BUG_ON(RB_EMPTY_NODE(&last
->rb_node
));
1135 prev
= rb_entry_rq(rbprev
);
1138 next
= rb_entry_rq(rbnext
);
1140 rbnext
= rb_first(&cfqq
->sort_list
);
1141 if (rbnext
&& rbnext
!= &last
->rb_node
)
1142 next
= rb_entry_rq(rbnext
);
1145 return cfq_choose_req(cfqd
, next
, prev
, blk_rq_pos(last
));
1148 static unsigned long cfq_slice_offset(struct cfq_data
*cfqd
,
1149 struct cfq_queue
*cfqq
)
1152 * just an approximation, should be ok.
1154 return (cfqq
->cfqg
->nr_cfqq
- 1) * (cfq_prio_slice(cfqd
, 1, 0) -
1155 cfq_prio_slice(cfqd
, cfq_cfqq_sync(cfqq
), cfqq
->ioprio
));
1159 cfqg_key(struct cfq_rb_root
*st
, struct cfq_group
*cfqg
)
1161 return cfqg
->vdisktime
- st
->min_vdisktime
;
1165 __cfq_group_service_tree_add(struct cfq_rb_root
*st
, struct cfq_group
*cfqg
)
1167 struct rb_node
**node
= &st
->rb
.rb_node
;
1168 struct rb_node
*parent
= NULL
;
1169 struct cfq_group
*__cfqg
;
1170 s64 key
= cfqg_key(st
, cfqg
);
1173 while (*node
!= NULL
) {
1175 __cfqg
= rb_entry_cfqg(parent
);
1177 if (key
< cfqg_key(st
, __cfqg
))
1178 node
= &parent
->rb_left
;
1180 node
= &parent
->rb_right
;
1186 st
->left
= &cfqg
->rb_node
;
1188 rb_link_node(&cfqg
->rb_node
, parent
, node
);
1189 rb_insert_color(&cfqg
->rb_node
, &st
->rb
);
1193 cfq_update_group_weight(struct cfq_group
*cfqg
)
1195 BUG_ON(!RB_EMPTY_NODE(&cfqg
->rb_node
));
1197 if (cfqg
->new_weight
) {
1198 cfqg
->weight
= cfqg
->new_weight
;
1199 cfqg
->new_weight
= 0;
1202 if (cfqg
->new_leaf_weight
) {
1203 cfqg
->leaf_weight
= cfqg
->new_leaf_weight
;
1204 cfqg
->new_leaf_weight
= 0;
1209 cfq_group_service_tree_add(struct cfq_rb_root
*st
, struct cfq_group
*cfqg
)
1211 BUG_ON(!RB_EMPTY_NODE(&cfqg
->rb_node
));
1213 cfq_update_group_weight(cfqg
);
1214 __cfq_group_service_tree_add(st
, cfqg
);
1215 st
->total_weight
+= cfqg
->weight
;
1219 cfq_group_notify_queue_add(struct cfq_data
*cfqd
, struct cfq_group
*cfqg
)
1221 struct cfq_rb_root
*st
= &cfqd
->grp_service_tree
;
1222 struct cfq_group
*__cfqg
;
1226 if (!RB_EMPTY_NODE(&cfqg
->rb_node
))
1230 * Currently put the group at the end. Later implement something
1231 * so that groups get lesser vtime based on their weights, so that
1232 * if group does not loose all if it was not continuously backlogged.
1234 n
= rb_last(&st
->rb
);
1236 __cfqg
= rb_entry_cfqg(n
);
1237 cfqg
->vdisktime
= __cfqg
->vdisktime
+ CFQ_IDLE_DELAY
;
1239 cfqg
->vdisktime
= st
->min_vdisktime
;
1240 cfq_group_service_tree_add(st
, cfqg
);
1244 cfq_group_service_tree_del(struct cfq_rb_root
*st
, struct cfq_group
*cfqg
)
1246 st
->total_weight
-= cfqg
->weight
;
1247 if (!RB_EMPTY_NODE(&cfqg
->rb_node
))
1248 cfq_rb_erase(&cfqg
->rb_node
, st
);
1252 cfq_group_notify_queue_del(struct cfq_data
*cfqd
, struct cfq_group
*cfqg
)
1254 struct cfq_rb_root
*st
= &cfqd
->grp_service_tree
;
1256 BUG_ON(cfqg
->nr_cfqq
< 1);
1259 /* If there are other cfq queues under this group, don't delete it */
1263 cfq_log_cfqg(cfqd
, cfqg
, "del_from_rr group");
1264 cfq_group_service_tree_del(st
, cfqg
);
1265 cfqg
->saved_wl_slice
= 0;
1266 cfqg_stats_update_dequeue(cfqg
);
1269 static inline unsigned int cfq_cfqq_slice_usage(struct cfq_queue
*cfqq
,
1270 unsigned int *unaccounted_time
)
1272 unsigned int slice_used
;
1275 * Queue got expired before even a single request completed or
1276 * got expired immediately after first request completion.
1278 if (!cfqq
->slice_start
|| cfqq
->slice_start
== jiffies
) {
1280 * Also charge the seek time incurred to the group, otherwise
1281 * if there are mutiple queues in the group, each can dispatch
1282 * a single request on seeky media and cause lots of seek time
1283 * and group will never know it.
1285 slice_used
= max_t(unsigned, (jiffies
- cfqq
->dispatch_start
),
1288 slice_used
= jiffies
- cfqq
->slice_start
;
1289 if (slice_used
> cfqq
->allocated_slice
) {
1290 *unaccounted_time
= slice_used
- cfqq
->allocated_slice
;
1291 slice_used
= cfqq
->allocated_slice
;
1293 if (time_after(cfqq
->slice_start
, cfqq
->dispatch_start
))
1294 *unaccounted_time
+= cfqq
->slice_start
-
1295 cfqq
->dispatch_start
;
1301 static void cfq_group_served(struct cfq_data
*cfqd
, struct cfq_group
*cfqg
,
1302 struct cfq_queue
*cfqq
)
1304 struct cfq_rb_root
*st
= &cfqd
->grp_service_tree
;
1305 unsigned int used_sl
, charge
, unaccounted_sl
= 0;
1306 int nr_sync
= cfqg
->nr_cfqq
- cfqg_busy_async_queues(cfqd
, cfqg
)
1307 - cfqg
->service_tree_idle
.count
;
1309 BUG_ON(nr_sync
< 0);
1310 used_sl
= charge
= cfq_cfqq_slice_usage(cfqq
, &unaccounted_sl
);
1312 if (iops_mode(cfqd
))
1313 charge
= cfqq
->slice_dispatch
;
1314 else if (!cfq_cfqq_sync(cfqq
) && !nr_sync
)
1315 charge
= cfqq
->allocated_slice
;
1317 /* Can't update vdisktime while group is on service tree */
1318 cfq_group_service_tree_del(st
, cfqg
);
1319 cfqg
->vdisktime
+= cfq_scale_slice(charge
, cfqg
);
1320 /* If a new weight was requested, update now, off tree */
1321 cfq_group_service_tree_add(st
, cfqg
);
1323 /* This group is being expired. Save the context */
1324 if (time_after(cfqd
->workload_expires
, jiffies
)) {
1325 cfqg
->saved_wl_slice
= cfqd
->workload_expires
1327 cfqg
->saved_wl_type
= cfqd
->serving_wl_type
;
1328 cfqg
->saved_wl_class
= cfqd
->serving_wl_class
;
1330 cfqg
->saved_wl_slice
= 0;
1332 cfq_log_cfqg(cfqd
, cfqg
, "served: vt=%llu min_vt=%llu", cfqg
->vdisktime
,
1334 cfq_log_cfqq(cfqq
->cfqd
, cfqq
,
1335 "sl_used=%u disp=%u charge=%u iops=%u sect=%lu",
1336 used_sl
, cfqq
->slice_dispatch
, charge
,
1337 iops_mode(cfqd
), cfqq
->nr_sectors
);
1338 cfqg_stats_update_timeslice_used(cfqg
, used_sl
, unaccounted_sl
);
1339 cfqg_stats_set_start_empty_time(cfqg
);
1343 * cfq_init_cfqg_base - initialize base part of a cfq_group
1344 * @cfqg: cfq_group to initialize
1346 * Initialize the base part which is used whether %CONFIG_CFQ_GROUP_IOSCHED
1347 * is enabled or not.
1349 static void cfq_init_cfqg_base(struct cfq_group
*cfqg
)
1351 struct cfq_rb_root
*st
;
1354 for_each_cfqg_st(cfqg
, i
, j
, st
)
1356 RB_CLEAR_NODE(&cfqg
->rb_node
);
1358 cfqg
->ttime
.last_end_request
= jiffies
;
1361 #ifdef CONFIG_CFQ_GROUP_IOSCHED
1362 static void cfq_pd_init(struct blkcg_gq
*blkg
)
1364 struct cfq_group
*cfqg
= blkg_to_cfqg(blkg
);
1366 cfq_init_cfqg_base(cfqg
);
1367 cfqg
->weight
= blkg
->blkcg
->cfq_weight
;
1368 cfqg
->leaf_weight
= blkg
->blkcg
->cfq_leaf_weight
;
1372 * Search for the cfq group current task belongs to. request_queue lock must
1375 static struct cfq_group
*cfq_lookup_create_cfqg(struct cfq_data
*cfqd
,
1376 struct blkcg
*blkcg
)
1378 struct request_queue
*q
= cfqd
->queue
;
1379 struct cfq_group
*cfqg
= NULL
;
1381 /* avoid lookup for the common case where there's no blkcg */
1382 if (blkcg
== &blkcg_root
) {
1383 cfqg
= cfqd
->root_group
;
1385 struct blkcg_gq
*blkg
;
1387 blkg
= blkg_lookup_create(blkcg
, q
);
1389 cfqg
= blkg_to_cfqg(blkg
);
1395 static void cfq_link_cfqq_cfqg(struct cfq_queue
*cfqq
, struct cfq_group
*cfqg
)
1397 /* Currently, all async queues are mapped to root group */
1398 if (!cfq_cfqq_sync(cfqq
))
1399 cfqg
= cfqq
->cfqd
->root_group
;
1402 /* cfqq reference on cfqg */
1406 static u64
cfqg_prfill_weight_device(struct seq_file
*sf
,
1407 struct blkg_policy_data
*pd
, int off
)
1409 struct cfq_group
*cfqg
= pd_to_cfqg(pd
);
1411 if (!cfqg
->dev_weight
)
1413 return __blkg_prfill_u64(sf
, pd
, cfqg
->dev_weight
);
1416 static int cfqg_print_weight_device(struct cgroup
*cgrp
, struct cftype
*cft
,
1417 struct seq_file
*sf
)
1419 blkcg_print_blkgs(sf
, cgroup_to_blkcg(cgrp
),
1420 cfqg_prfill_weight_device
, &blkcg_policy_cfq
, 0,
1425 static u64
cfqg_prfill_leaf_weight_device(struct seq_file
*sf
,
1426 struct blkg_policy_data
*pd
, int off
)
1428 struct cfq_group
*cfqg
= pd_to_cfqg(pd
);
1430 if (!cfqg
->dev_leaf_weight
)
1432 return __blkg_prfill_u64(sf
, pd
, cfqg
->dev_leaf_weight
);
1435 static int cfqg_print_leaf_weight_device(struct cgroup
*cgrp
,
1437 struct seq_file
*sf
)
1439 blkcg_print_blkgs(sf
, cgroup_to_blkcg(cgrp
),
1440 cfqg_prfill_leaf_weight_device
, &blkcg_policy_cfq
, 0,
1445 static int cfq_print_weight(struct cgroup
*cgrp
, struct cftype
*cft
,
1446 struct seq_file
*sf
)
1448 seq_printf(sf
, "%u\n", cgroup_to_blkcg(cgrp
)->cfq_weight
);
1452 static int cfq_print_leaf_weight(struct cgroup
*cgrp
, struct cftype
*cft
,
1453 struct seq_file
*sf
)
1455 seq_printf(sf
, "%u\n",
1456 cgroup_to_blkcg(cgrp
)->cfq_leaf_weight
);
1460 static int __cfqg_set_weight_device(struct cgroup
*cgrp
, struct cftype
*cft
,
1461 const char *buf
, bool is_leaf_weight
)
1463 struct blkcg
*blkcg
= cgroup_to_blkcg(cgrp
);
1464 struct blkg_conf_ctx ctx
;
1465 struct cfq_group
*cfqg
;
1468 ret
= blkg_conf_prep(blkcg
, &blkcg_policy_cfq
, buf
, &ctx
);
1473 cfqg
= blkg_to_cfqg(ctx
.blkg
);
1474 if (!ctx
.v
|| (ctx
.v
>= CFQ_WEIGHT_MIN
&& ctx
.v
<= CFQ_WEIGHT_MAX
)) {
1475 if (!is_leaf_weight
) {
1476 cfqg
->dev_weight
= ctx
.v
;
1477 cfqg
->new_weight
= ctx
.v
?: blkcg
->cfq_weight
;
1479 cfqg
->dev_leaf_weight
= ctx
.v
;
1480 cfqg
->new_leaf_weight
= ctx
.v
?: blkcg
->cfq_leaf_weight
;
1485 blkg_conf_finish(&ctx
);
1489 static int cfqg_set_weight_device(struct cgroup
*cgrp
, struct cftype
*cft
,
1492 return __cfqg_set_weight_device(cgrp
, cft
, buf
, false);
1495 static int cfqg_set_leaf_weight_device(struct cgroup
*cgrp
, struct cftype
*cft
,
1498 return __cfqg_set_weight_device(cgrp
, cft
, buf
, true);
1501 static int __cfq_set_weight(struct cgroup
*cgrp
, struct cftype
*cft
, u64 val
,
1502 bool is_leaf_weight
)
1504 struct blkcg
*blkcg
= cgroup_to_blkcg(cgrp
);
1505 struct blkcg_gq
*blkg
;
1506 struct hlist_node
*n
;
1508 if (val
< CFQ_WEIGHT_MIN
|| val
> CFQ_WEIGHT_MAX
)
1511 spin_lock_irq(&blkcg
->lock
);
1513 if (!is_leaf_weight
)
1514 blkcg
->cfq_weight
= val
;
1516 blkcg
->cfq_leaf_weight
= val
;
1518 hlist_for_each_entry(blkg
, n
, &blkcg
->blkg_list
, blkcg_node
) {
1519 struct cfq_group
*cfqg
= blkg_to_cfqg(blkg
);
1524 if (!is_leaf_weight
) {
1525 if (!cfqg
->dev_weight
)
1526 cfqg
->new_weight
= blkcg
->cfq_weight
;
1528 if (!cfqg
->dev_leaf_weight
)
1529 cfqg
->new_leaf_weight
= blkcg
->cfq_leaf_weight
;
1533 spin_unlock_irq(&blkcg
->lock
);
1537 static int cfq_set_weight(struct cgroup
*cgrp
, struct cftype
*cft
, u64 val
)
1539 return __cfq_set_weight(cgrp
, cft
, val
, false);
1542 static int cfq_set_leaf_weight(struct cgroup
*cgrp
, struct cftype
*cft
, u64 val
)
1544 return __cfq_set_weight(cgrp
, cft
, val
, true);
1547 static int cfqg_print_stat(struct cgroup
*cgrp
, struct cftype
*cft
,
1548 struct seq_file
*sf
)
1550 struct blkcg
*blkcg
= cgroup_to_blkcg(cgrp
);
1552 blkcg_print_blkgs(sf
, blkcg
, blkg_prfill_stat
, &blkcg_policy_cfq
,
1553 cft
->private, false);
1557 static int cfqg_print_rwstat(struct cgroup
*cgrp
, struct cftype
*cft
,
1558 struct seq_file
*sf
)
1560 struct blkcg
*blkcg
= cgroup_to_blkcg(cgrp
);
1562 blkcg_print_blkgs(sf
, blkcg
, blkg_prfill_rwstat
, &blkcg_policy_cfq
,
1563 cft
->private, true);
1567 #ifdef CONFIG_DEBUG_BLK_CGROUP
1568 static u64
cfqg_prfill_avg_queue_size(struct seq_file
*sf
,
1569 struct blkg_policy_data
*pd
, int off
)
1571 struct cfq_group
*cfqg
= pd_to_cfqg(pd
);
1572 u64 samples
= blkg_stat_read(&cfqg
->stats
.avg_queue_size_samples
);
1576 v
= blkg_stat_read(&cfqg
->stats
.avg_queue_size_sum
);
1579 __blkg_prfill_u64(sf
, pd
, v
);
1583 /* print avg_queue_size */
1584 static int cfqg_print_avg_queue_size(struct cgroup
*cgrp
, struct cftype
*cft
,
1585 struct seq_file
*sf
)
1587 struct blkcg
*blkcg
= cgroup_to_blkcg(cgrp
);
1589 blkcg_print_blkgs(sf
, blkcg
, cfqg_prfill_avg_queue_size
,
1590 &blkcg_policy_cfq
, 0, false);
1593 #endif /* CONFIG_DEBUG_BLK_CGROUP */
1595 static struct cftype cfq_blkcg_files
[] = {
1597 .name
= "weight_device",
1598 .read_seq_string
= cfqg_print_weight_device
,
1599 .write_string
= cfqg_set_weight_device
,
1600 .max_write_len
= 256,
1604 .read_seq_string
= cfq_print_weight
,
1605 .write_u64
= cfq_set_weight
,
1608 /* on root, leaf_weight is mapped to weight */
1610 .name
= "leaf_weight_device",
1611 .flags
= CFTYPE_ONLY_ON_ROOT
,
1612 .read_seq_string
= cfqg_print_weight_device
,
1613 .write_string
= cfqg_set_weight_device
,
1614 .max_write_len
= 256,
1617 .name
= "leaf_weight",
1618 .flags
= CFTYPE_ONLY_ON_ROOT
,
1619 .read_seq_string
= cfq_print_weight
,
1620 .write_u64
= cfq_set_weight
,
1623 /* no such mapping necessary for !roots */
1625 .name
= "leaf_weight_device",
1626 .flags
= CFTYPE_NOT_ON_ROOT
,
1627 .read_seq_string
= cfqg_print_leaf_weight_device
,
1628 .write_string
= cfqg_set_leaf_weight_device
,
1629 .max_write_len
= 256,
1632 .name
= "leaf_weight",
1633 .flags
= CFTYPE_NOT_ON_ROOT
,
1634 .read_seq_string
= cfq_print_leaf_weight
,
1635 .write_u64
= cfq_set_leaf_weight
,
1640 .private = offsetof(struct cfq_group
, stats
.time
),
1641 .read_seq_string
= cfqg_print_stat
,
1645 .private = offsetof(struct cfq_group
, stats
.sectors
),
1646 .read_seq_string
= cfqg_print_stat
,
1649 .name
= "io_service_bytes",
1650 .private = offsetof(struct cfq_group
, stats
.service_bytes
),
1651 .read_seq_string
= cfqg_print_rwstat
,
1654 .name
= "io_serviced",
1655 .private = offsetof(struct cfq_group
, stats
.serviced
),
1656 .read_seq_string
= cfqg_print_rwstat
,
1659 .name
= "io_service_time",
1660 .private = offsetof(struct cfq_group
, stats
.service_time
),
1661 .read_seq_string
= cfqg_print_rwstat
,
1664 .name
= "io_wait_time",
1665 .private = offsetof(struct cfq_group
, stats
.wait_time
),
1666 .read_seq_string
= cfqg_print_rwstat
,
1669 .name
= "io_merged",
1670 .private = offsetof(struct cfq_group
, stats
.merged
),
1671 .read_seq_string
= cfqg_print_rwstat
,
1674 .name
= "io_queued",
1675 .private = offsetof(struct cfq_group
, stats
.queued
),
1676 .read_seq_string
= cfqg_print_rwstat
,
1678 #ifdef CONFIG_DEBUG_BLK_CGROUP
1680 .name
= "avg_queue_size",
1681 .read_seq_string
= cfqg_print_avg_queue_size
,
1684 .name
= "group_wait_time",
1685 .private = offsetof(struct cfq_group
, stats
.group_wait_time
),
1686 .read_seq_string
= cfqg_print_stat
,
1689 .name
= "idle_time",
1690 .private = offsetof(struct cfq_group
, stats
.idle_time
),
1691 .read_seq_string
= cfqg_print_stat
,
1694 .name
= "empty_time",
1695 .private = offsetof(struct cfq_group
, stats
.empty_time
),
1696 .read_seq_string
= cfqg_print_stat
,
1700 .private = offsetof(struct cfq_group
, stats
.dequeue
),
1701 .read_seq_string
= cfqg_print_stat
,
1704 .name
= "unaccounted_time",
1705 .private = offsetof(struct cfq_group
, stats
.unaccounted_time
),
1706 .read_seq_string
= cfqg_print_stat
,
1708 #endif /* CONFIG_DEBUG_BLK_CGROUP */
1711 #else /* GROUP_IOSCHED */
1712 static struct cfq_group
*cfq_lookup_create_cfqg(struct cfq_data
*cfqd
,
1713 struct blkcg
*blkcg
)
1715 return cfqd
->root_group
;
1719 cfq_link_cfqq_cfqg(struct cfq_queue
*cfqq
, struct cfq_group
*cfqg
) {
1723 #endif /* GROUP_IOSCHED */
1726 * The cfqd->service_trees holds all pending cfq_queue's that have
1727 * requests waiting to be processed. It is sorted in the order that
1728 * we will service the queues.
1730 static void cfq_service_tree_add(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
1733 struct rb_node
**p
, *parent
;
1734 struct cfq_queue
*__cfqq
;
1735 unsigned long rb_key
;
1736 struct cfq_rb_root
*st
;
1740 st
= st_for(cfqq
->cfqg
, cfqq_class(cfqq
), cfqq_type(cfqq
));
1741 if (cfq_class_idle(cfqq
)) {
1742 rb_key
= CFQ_IDLE_DELAY
;
1743 parent
= rb_last(&st
->rb
);
1744 if (parent
&& parent
!= &cfqq
->rb_node
) {
1745 __cfqq
= rb_entry(parent
, struct cfq_queue
, rb_node
);
1746 rb_key
+= __cfqq
->rb_key
;
1749 } else if (!add_front
) {
1751 * Get our rb key offset. Subtract any residual slice
1752 * value carried from last service. A negative resid
1753 * count indicates slice overrun, and this should position
1754 * the next service time further away in the tree.
1756 rb_key
= cfq_slice_offset(cfqd
, cfqq
) + jiffies
;
1757 rb_key
-= cfqq
->slice_resid
;
1758 cfqq
->slice_resid
= 0;
1761 __cfqq
= cfq_rb_first(st
);
1762 rb_key
+= __cfqq
? __cfqq
->rb_key
: jiffies
;
1765 if (!RB_EMPTY_NODE(&cfqq
->rb_node
)) {
1768 * same position, nothing more to do
1770 if (rb_key
== cfqq
->rb_key
&& cfqq
->service_tree
== st
)
1773 cfq_rb_erase(&cfqq
->rb_node
, cfqq
->service_tree
);
1774 cfqq
->service_tree
= NULL
;
1779 cfqq
->service_tree
= st
;
1780 p
= &st
->rb
.rb_node
;
1783 __cfqq
= rb_entry(parent
, struct cfq_queue
, rb_node
);
1786 * sort by key, that represents service time.
1788 if (time_before(rb_key
, __cfqq
->rb_key
))
1789 p
= &parent
->rb_left
;
1791 p
= &parent
->rb_right
;
1797 st
->left
= &cfqq
->rb_node
;
1799 cfqq
->rb_key
= rb_key
;
1800 rb_link_node(&cfqq
->rb_node
, parent
, p
);
1801 rb_insert_color(&cfqq
->rb_node
, &st
->rb
);
1803 if (add_front
|| !new_cfqq
)
1805 cfq_group_notify_queue_add(cfqd
, cfqq
->cfqg
);
1808 static struct cfq_queue
*
1809 cfq_prio_tree_lookup(struct cfq_data
*cfqd
, struct rb_root
*root
,
1810 sector_t sector
, struct rb_node
**ret_parent
,
1811 struct rb_node
***rb_link
)
1813 struct rb_node
**p
, *parent
;
1814 struct cfq_queue
*cfqq
= NULL
;
1822 cfqq
= rb_entry(parent
, struct cfq_queue
, p_node
);
1825 * Sort strictly based on sector. Smallest to the left,
1826 * largest to the right.
1828 if (sector
> blk_rq_pos(cfqq
->next_rq
))
1829 n
= &(*p
)->rb_right
;
1830 else if (sector
< blk_rq_pos(cfqq
->next_rq
))
1838 *ret_parent
= parent
;
1844 static void cfq_prio_tree_add(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
1846 struct rb_node
**p
, *parent
;
1847 struct cfq_queue
*__cfqq
;
1850 rb_erase(&cfqq
->p_node
, cfqq
->p_root
);
1851 cfqq
->p_root
= NULL
;
1854 if (cfq_class_idle(cfqq
))
1859 cfqq
->p_root
= &cfqd
->prio_trees
[cfqq
->org_ioprio
];
1860 __cfqq
= cfq_prio_tree_lookup(cfqd
, cfqq
->p_root
,
1861 blk_rq_pos(cfqq
->next_rq
), &parent
, &p
);
1863 rb_link_node(&cfqq
->p_node
, parent
, p
);
1864 rb_insert_color(&cfqq
->p_node
, cfqq
->p_root
);
1866 cfqq
->p_root
= NULL
;
1870 * Update cfqq's position in the service tree.
1872 static void cfq_resort_rr_list(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
1875 * Resorting requires the cfqq to be on the RR list already.
1877 if (cfq_cfqq_on_rr(cfqq
)) {
1878 cfq_service_tree_add(cfqd
, cfqq
, 0);
1879 cfq_prio_tree_add(cfqd
, cfqq
);
1884 * add to busy list of queues for service, trying to be fair in ordering
1885 * the pending list according to last request service
1887 static void cfq_add_cfqq_rr(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
1889 cfq_log_cfqq(cfqd
, cfqq
, "add_to_rr");
1890 BUG_ON(cfq_cfqq_on_rr(cfqq
));
1891 cfq_mark_cfqq_on_rr(cfqq
);
1892 cfqd
->busy_queues
++;
1893 if (cfq_cfqq_sync(cfqq
))
1894 cfqd
->busy_sync_queues
++;
1896 cfq_resort_rr_list(cfqd
, cfqq
);
1900 * Called when the cfqq no longer has requests pending, remove it from
1903 static void cfq_del_cfqq_rr(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
1905 cfq_log_cfqq(cfqd
, cfqq
, "del_from_rr");
1906 BUG_ON(!cfq_cfqq_on_rr(cfqq
));
1907 cfq_clear_cfqq_on_rr(cfqq
);
1909 if (!RB_EMPTY_NODE(&cfqq
->rb_node
)) {
1910 cfq_rb_erase(&cfqq
->rb_node
, cfqq
->service_tree
);
1911 cfqq
->service_tree
= NULL
;
1914 rb_erase(&cfqq
->p_node
, cfqq
->p_root
);
1915 cfqq
->p_root
= NULL
;
1918 cfq_group_notify_queue_del(cfqd
, cfqq
->cfqg
);
1919 BUG_ON(!cfqd
->busy_queues
);
1920 cfqd
->busy_queues
--;
1921 if (cfq_cfqq_sync(cfqq
))
1922 cfqd
->busy_sync_queues
--;
1926 * rb tree support functions
1928 static void cfq_del_rq_rb(struct request
*rq
)
1930 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
1931 const int sync
= rq_is_sync(rq
);
1933 BUG_ON(!cfqq
->queued
[sync
]);
1934 cfqq
->queued
[sync
]--;
1936 elv_rb_del(&cfqq
->sort_list
, rq
);
1938 if (cfq_cfqq_on_rr(cfqq
) && RB_EMPTY_ROOT(&cfqq
->sort_list
)) {
1940 * Queue will be deleted from service tree when we actually
1941 * expire it later. Right now just remove it from prio tree
1945 rb_erase(&cfqq
->p_node
, cfqq
->p_root
);
1946 cfqq
->p_root
= NULL
;
1951 static void cfq_add_rq_rb(struct request
*rq
)
1953 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
1954 struct cfq_data
*cfqd
= cfqq
->cfqd
;
1955 struct request
*prev
;
1957 cfqq
->queued
[rq_is_sync(rq
)]++;
1959 elv_rb_add(&cfqq
->sort_list
, rq
);
1961 if (!cfq_cfqq_on_rr(cfqq
))
1962 cfq_add_cfqq_rr(cfqd
, cfqq
);
1965 * check if this request is a better next-serve candidate
1967 prev
= cfqq
->next_rq
;
1968 cfqq
->next_rq
= cfq_choose_req(cfqd
, cfqq
->next_rq
, rq
, cfqd
->last_position
);
1971 * adjust priority tree position, if ->next_rq changes
1973 if (prev
!= cfqq
->next_rq
)
1974 cfq_prio_tree_add(cfqd
, cfqq
);
1976 BUG_ON(!cfqq
->next_rq
);
1979 static void cfq_reposition_rq_rb(struct cfq_queue
*cfqq
, struct request
*rq
)
1981 elv_rb_del(&cfqq
->sort_list
, rq
);
1982 cfqq
->queued
[rq_is_sync(rq
)]--;
1983 cfqg_stats_update_io_remove(RQ_CFQG(rq
), rq
->cmd_flags
);
1985 cfqg_stats_update_io_add(RQ_CFQG(rq
), cfqq
->cfqd
->serving_group
,
1989 static struct request
*
1990 cfq_find_rq_fmerge(struct cfq_data
*cfqd
, struct bio
*bio
)
1992 struct task_struct
*tsk
= current
;
1993 struct cfq_io_cq
*cic
;
1994 struct cfq_queue
*cfqq
;
1996 cic
= cfq_cic_lookup(cfqd
, tsk
->io_context
);
2000 cfqq
= cic_to_cfqq(cic
, cfq_bio_sync(bio
));
2002 sector_t sector
= bio
->bi_sector
+ bio_sectors(bio
);
2004 return elv_rb_find(&cfqq
->sort_list
, sector
);
2010 static void cfq_activate_request(struct request_queue
*q
, struct request
*rq
)
2012 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
2014 cfqd
->rq_in_driver
++;
2015 cfq_log_cfqq(cfqd
, RQ_CFQQ(rq
), "activate rq, drv=%d",
2016 cfqd
->rq_in_driver
);
2018 cfqd
->last_position
= blk_rq_pos(rq
) + blk_rq_sectors(rq
);
2021 static void cfq_deactivate_request(struct request_queue
*q
, struct request
*rq
)
2023 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
2025 WARN_ON(!cfqd
->rq_in_driver
);
2026 cfqd
->rq_in_driver
--;
2027 cfq_log_cfqq(cfqd
, RQ_CFQQ(rq
), "deactivate rq, drv=%d",
2028 cfqd
->rq_in_driver
);
2031 static void cfq_remove_request(struct request
*rq
)
2033 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
2035 if (cfqq
->next_rq
== rq
)
2036 cfqq
->next_rq
= cfq_find_next_rq(cfqq
->cfqd
, cfqq
, rq
);
2038 list_del_init(&rq
->queuelist
);
2041 cfqq
->cfqd
->rq_queued
--;
2042 cfqg_stats_update_io_remove(RQ_CFQG(rq
), rq
->cmd_flags
);
2043 if (rq
->cmd_flags
& REQ_PRIO
) {
2044 WARN_ON(!cfqq
->prio_pending
);
2045 cfqq
->prio_pending
--;
2049 static int cfq_merge(struct request_queue
*q
, struct request
**req
,
2052 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
2053 struct request
*__rq
;
2055 __rq
= cfq_find_rq_fmerge(cfqd
, bio
);
2056 if (__rq
&& elv_rq_merge_ok(__rq
, bio
)) {
2058 return ELEVATOR_FRONT_MERGE
;
2061 return ELEVATOR_NO_MERGE
;
2064 static void cfq_merged_request(struct request_queue
*q
, struct request
*req
,
2067 if (type
== ELEVATOR_FRONT_MERGE
) {
2068 struct cfq_queue
*cfqq
= RQ_CFQQ(req
);
2070 cfq_reposition_rq_rb(cfqq
, req
);
2074 static void cfq_bio_merged(struct request_queue
*q
, struct request
*req
,
2077 cfqg_stats_update_io_merged(RQ_CFQG(req
), bio
->bi_rw
);
2081 cfq_merged_requests(struct request_queue
*q
, struct request
*rq
,
2082 struct request
*next
)
2084 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
2085 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
2088 * reposition in fifo if next is older than rq
2090 if (!list_empty(&rq
->queuelist
) && !list_empty(&next
->queuelist
) &&
2091 time_before(rq_fifo_time(next
), rq_fifo_time(rq
)) &&
2092 cfqq
== RQ_CFQQ(next
)) {
2093 list_move(&rq
->queuelist
, &next
->queuelist
);
2094 rq_set_fifo_time(rq
, rq_fifo_time(next
));
2097 if (cfqq
->next_rq
== next
)
2099 cfq_remove_request(next
);
2100 cfqg_stats_update_io_merged(RQ_CFQG(rq
), next
->cmd_flags
);
2102 cfqq
= RQ_CFQQ(next
);
2104 * all requests of this queue are merged to other queues, delete it
2105 * from the service tree. If it's the active_queue,
2106 * cfq_dispatch_requests() will choose to expire it or do idle
2108 if (cfq_cfqq_on_rr(cfqq
) && RB_EMPTY_ROOT(&cfqq
->sort_list
) &&
2109 cfqq
!= cfqd
->active_queue
)
2110 cfq_del_cfqq_rr(cfqd
, cfqq
);
2113 static int cfq_allow_merge(struct request_queue
*q
, struct request
*rq
,
2116 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
2117 struct cfq_io_cq
*cic
;
2118 struct cfq_queue
*cfqq
;
2121 * Disallow merge of a sync bio into an async request.
2123 if (cfq_bio_sync(bio
) && !rq_is_sync(rq
))
2127 * Lookup the cfqq that this bio will be queued with and allow
2128 * merge only if rq is queued there.
2130 cic
= cfq_cic_lookup(cfqd
, current
->io_context
);
2134 cfqq
= cic_to_cfqq(cic
, cfq_bio_sync(bio
));
2135 return cfqq
== RQ_CFQQ(rq
);
2138 static inline void cfq_del_timer(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
2140 del_timer(&cfqd
->idle_slice_timer
);
2141 cfqg_stats_update_idle_time(cfqq
->cfqg
);
2144 static void __cfq_set_active_queue(struct cfq_data
*cfqd
,
2145 struct cfq_queue
*cfqq
)
2148 cfq_log_cfqq(cfqd
, cfqq
, "set_active wl_class:%d wl_type:%d",
2149 cfqd
->serving_wl_class
, cfqd
->serving_wl_type
);
2150 cfqg_stats_update_avg_queue_size(cfqq
->cfqg
);
2151 cfqq
->slice_start
= 0;
2152 cfqq
->dispatch_start
= jiffies
;
2153 cfqq
->allocated_slice
= 0;
2154 cfqq
->slice_end
= 0;
2155 cfqq
->slice_dispatch
= 0;
2156 cfqq
->nr_sectors
= 0;
2158 cfq_clear_cfqq_wait_request(cfqq
);
2159 cfq_clear_cfqq_must_dispatch(cfqq
);
2160 cfq_clear_cfqq_must_alloc_slice(cfqq
);
2161 cfq_clear_cfqq_fifo_expire(cfqq
);
2162 cfq_mark_cfqq_slice_new(cfqq
);
2164 cfq_del_timer(cfqd
, cfqq
);
2167 cfqd
->active_queue
= cfqq
;
2171 * current cfqq expired its slice (or was too idle), select new one
2174 __cfq_slice_expired(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
2177 cfq_log_cfqq(cfqd
, cfqq
, "slice expired t=%d", timed_out
);
2179 if (cfq_cfqq_wait_request(cfqq
))
2180 cfq_del_timer(cfqd
, cfqq
);
2182 cfq_clear_cfqq_wait_request(cfqq
);
2183 cfq_clear_cfqq_wait_busy(cfqq
);
2186 * If this cfqq is shared between multiple processes, check to
2187 * make sure that those processes are still issuing I/Os within
2188 * the mean seek distance. If not, it may be time to break the
2189 * queues apart again.
2191 if (cfq_cfqq_coop(cfqq
) && CFQQ_SEEKY(cfqq
))
2192 cfq_mark_cfqq_split_coop(cfqq
);
2195 * store what was left of this slice, if the queue idled/timed out
2198 if (cfq_cfqq_slice_new(cfqq
))
2199 cfqq
->slice_resid
= cfq_scaled_cfqq_slice(cfqd
, cfqq
);
2201 cfqq
->slice_resid
= cfqq
->slice_end
- jiffies
;
2202 cfq_log_cfqq(cfqd
, cfqq
, "resid=%ld", cfqq
->slice_resid
);
2205 cfq_group_served(cfqd
, cfqq
->cfqg
, cfqq
);
2207 if (cfq_cfqq_on_rr(cfqq
) && RB_EMPTY_ROOT(&cfqq
->sort_list
))
2208 cfq_del_cfqq_rr(cfqd
, cfqq
);
2210 cfq_resort_rr_list(cfqd
, cfqq
);
2212 if (cfqq
== cfqd
->active_queue
)
2213 cfqd
->active_queue
= NULL
;
2215 if (cfqd
->active_cic
) {
2216 put_io_context(cfqd
->active_cic
->icq
.ioc
);
2217 cfqd
->active_cic
= NULL
;
2221 static inline void cfq_slice_expired(struct cfq_data
*cfqd
, bool timed_out
)
2223 struct cfq_queue
*cfqq
= cfqd
->active_queue
;
2226 __cfq_slice_expired(cfqd
, cfqq
, timed_out
);
2230 * Get next queue for service. Unless we have a queue preemption,
2231 * we'll simply select the first cfqq in the service tree.
2233 static struct cfq_queue
*cfq_get_next_queue(struct cfq_data
*cfqd
)
2235 struct cfq_rb_root
*st
= st_for(cfqd
->serving_group
,
2236 cfqd
->serving_wl_class
, cfqd
->serving_wl_type
);
2238 if (!cfqd
->rq_queued
)
2241 /* There is nothing to dispatch */
2244 if (RB_EMPTY_ROOT(&st
->rb
))
2246 return cfq_rb_first(st
);
2249 static struct cfq_queue
*cfq_get_next_queue_forced(struct cfq_data
*cfqd
)
2251 struct cfq_group
*cfqg
;
2252 struct cfq_queue
*cfqq
;
2254 struct cfq_rb_root
*st
;
2256 if (!cfqd
->rq_queued
)
2259 cfqg
= cfq_get_next_cfqg(cfqd
);
2263 for_each_cfqg_st(cfqg
, i
, j
, st
)
2264 if ((cfqq
= cfq_rb_first(st
)) != NULL
)
2270 * Get and set a new active queue for service.
2272 static struct cfq_queue
*cfq_set_active_queue(struct cfq_data
*cfqd
,
2273 struct cfq_queue
*cfqq
)
2276 cfqq
= cfq_get_next_queue(cfqd
);
2278 __cfq_set_active_queue(cfqd
, cfqq
);
2282 static inline sector_t
cfq_dist_from_last(struct cfq_data
*cfqd
,
2285 if (blk_rq_pos(rq
) >= cfqd
->last_position
)
2286 return blk_rq_pos(rq
) - cfqd
->last_position
;
2288 return cfqd
->last_position
- blk_rq_pos(rq
);
2291 static inline int cfq_rq_close(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
2294 return cfq_dist_from_last(cfqd
, rq
) <= CFQQ_CLOSE_THR
;
2297 static struct cfq_queue
*cfqq_close(struct cfq_data
*cfqd
,
2298 struct cfq_queue
*cur_cfqq
)
2300 struct rb_root
*root
= &cfqd
->prio_trees
[cur_cfqq
->org_ioprio
];
2301 struct rb_node
*parent
, *node
;
2302 struct cfq_queue
*__cfqq
;
2303 sector_t sector
= cfqd
->last_position
;
2305 if (RB_EMPTY_ROOT(root
))
2309 * First, if we find a request starting at the end of the last
2310 * request, choose it.
2312 __cfqq
= cfq_prio_tree_lookup(cfqd
, root
, sector
, &parent
, NULL
);
2317 * If the exact sector wasn't found, the parent of the NULL leaf
2318 * will contain the closest sector.
2320 __cfqq
= rb_entry(parent
, struct cfq_queue
, p_node
);
2321 if (cfq_rq_close(cfqd
, cur_cfqq
, __cfqq
->next_rq
))
2324 if (blk_rq_pos(__cfqq
->next_rq
) < sector
)
2325 node
= rb_next(&__cfqq
->p_node
);
2327 node
= rb_prev(&__cfqq
->p_node
);
2331 __cfqq
= rb_entry(node
, struct cfq_queue
, p_node
);
2332 if (cfq_rq_close(cfqd
, cur_cfqq
, __cfqq
->next_rq
))
2340 * cur_cfqq - passed in so that we don't decide that the current queue is
2341 * closely cooperating with itself.
2343 * So, basically we're assuming that that cur_cfqq has dispatched at least
2344 * one request, and that cfqd->last_position reflects a position on the disk
2345 * associated with the I/O issued by cur_cfqq. I'm not sure this is a valid
2348 static struct cfq_queue
*cfq_close_cooperator(struct cfq_data
*cfqd
,
2349 struct cfq_queue
*cur_cfqq
)
2351 struct cfq_queue
*cfqq
;
2353 if (cfq_class_idle(cur_cfqq
))
2355 if (!cfq_cfqq_sync(cur_cfqq
))
2357 if (CFQQ_SEEKY(cur_cfqq
))
2361 * Don't search priority tree if it's the only queue in the group.
2363 if (cur_cfqq
->cfqg
->nr_cfqq
== 1)
2367 * We should notice if some of the queues are cooperating, eg
2368 * working closely on the same area of the disk. In that case,
2369 * we can group them together and don't waste time idling.
2371 cfqq
= cfqq_close(cfqd
, cur_cfqq
);
2375 /* If new queue belongs to different cfq_group, don't choose it */
2376 if (cur_cfqq
->cfqg
!= cfqq
->cfqg
)
2380 * It only makes sense to merge sync queues.
2382 if (!cfq_cfqq_sync(cfqq
))
2384 if (CFQQ_SEEKY(cfqq
))
2388 * Do not merge queues of different priority classes
2390 if (cfq_class_rt(cfqq
) != cfq_class_rt(cur_cfqq
))
2397 * Determine whether we should enforce idle window for this queue.
2400 static bool cfq_should_idle(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
2402 enum wl_class_t wl_class
= cfqq_class(cfqq
);
2403 struct cfq_rb_root
*st
= cfqq
->service_tree
;
2408 if (!cfqd
->cfq_slice_idle
)
2411 /* We never do for idle class queues. */
2412 if (wl_class
== IDLE_WORKLOAD
)
2415 /* We do for queues that were marked with idle window flag. */
2416 if (cfq_cfqq_idle_window(cfqq
) &&
2417 !(blk_queue_nonrot(cfqd
->queue
) && cfqd
->hw_tag
))
2421 * Otherwise, we do only if they are the last ones
2422 * in their service tree.
2424 if (st
->count
== 1 && cfq_cfqq_sync(cfqq
) &&
2425 !cfq_io_thinktime_big(cfqd
, &st
->ttime
, false))
2427 cfq_log_cfqq(cfqd
, cfqq
, "Not idling. st->count:%d", st
->count
);
2431 static void cfq_arm_slice_timer(struct cfq_data
*cfqd
)
2433 struct cfq_queue
*cfqq
= cfqd
->active_queue
;
2434 struct cfq_io_cq
*cic
;
2435 unsigned long sl
, group_idle
= 0;
2438 * SSD device without seek penalty, disable idling. But only do so
2439 * for devices that support queuing, otherwise we still have a problem
2440 * with sync vs async workloads.
2442 if (blk_queue_nonrot(cfqd
->queue
) && cfqd
->hw_tag
)
2445 WARN_ON(!RB_EMPTY_ROOT(&cfqq
->sort_list
));
2446 WARN_ON(cfq_cfqq_slice_new(cfqq
));
2449 * idle is disabled, either manually or by past process history
2451 if (!cfq_should_idle(cfqd
, cfqq
)) {
2452 /* no queue idling. Check for group idling */
2453 if (cfqd
->cfq_group_idle
)
2454 group_idle
= cfqd
->cfq_group_idle
;
2460 * still active requests from this queue, don't idle
2462 if (cfqq
->dispatched
)
2466 * task has exited, don't wait
2468 cic
= cfqd
->active_cic
;
2469 if (!cic
|| !atomic_read(&cic
->icq
.ioc
->active_ref
))
2473 * If our average think time is larger than the remaining time
2474 * slice, then don't idle. This avoids overrunning the allotted
2477 if (sample_valid(cic
->ttime
.ttime_samples
) &&
2478 (cfqq
->slice_end
- jiffies
< cic
->ttime
.ttime_mean
)) {
2479 cfq_log_cfqq(cfqd
, cfqq
, "Not idling. think_time:%lu",
2480 cic
->ttime
.ttime_mean
);
2484 /* There are other queues in the group, don't do group idle */
2485 if (group_idle
&& cfqq
->cfqg
->nr_cfqq
> 1)
2488 cfq_mark_cfqq_wait_request(cfqq
);
2491 sl
= cfqd
->cfq_group_idle
;
2493 sl
= cfqd
->cfq_slice_idle
;
2495 mod_timer(&cfqd
->idle_slice_timer
, jiffies
+ sl
);
2496 cfqg_stats_set_start_idle_time(cfqq
->cfqg
);
2497 cfq_log_cfqq(cfqd
, cfqq
, "arm_idle: %lu group_idle: %d", sl
,
2498 group_idle
? 1 : 0);
2502 * Move request from internal lists to the request queue dispatch list.
2504 static void cfq_dispatch_insert(struct request_queue
*q
, struct request
*rq
)
2506 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
2507 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
2509 cfq_log_cfqq(cfqd
, cfqq
, "dispatch_insert");
2511 cfqq
->next_rq
= cfq_find_next_rq(cfqd
, cfqq
, rq
);
2512 cfq_remove_request(rq
);
2514 (RQ_CFQG(rq
))->dispatched
++;
2515 elv_dispatch_sort(q
, rq
);
2517 cfqd
->rq_in_flight
[cfq_cfqq_sync(cfqq
)]++;
2518 cfqq
->nr_sectors
+= blk_rq_sectors(rq
);
2519 cfqg_stats_update_dispatch(cfqq
->cfqg
, blk_rq_bytes(rq
), rq
->cmd_flags
);
2523 * return expired entry, or NULL to just start from scratch in rbtree
2525 static struct request
*cfq_check_fifo(struct cfq_queue
*cfqq
)
2527 struct request
*rq
= NULL
;
2529 if (cfq_cfqq_fifo_expire(cfqq
))
2532 cfq_mark_cfqq_fifo_expire(cfqq
);
2534 if (list_empty(&cfqq
->fifo
))
2537 rq
= rq_entry_fifo(cfqq
->fifo
.next
);
2538 if (time_before(jiffies
, rq_fifo_time(rq
)))
2541 cfq_log_cfqq(cfqq
->cfqd
, cfqq
, "fifo=%p", rq
);
2546 cfq_prio_to_maxrq(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
2548 const int base_rq
= cfqd
->cfq_slice_async_rq
;
2550 WARN_ON(cfqq
->ioprio
>= IOPRIO_BE_NR
);
2552 return 2 * base_rq
* (IOPRIO_BE_NR
- cfqq
->ioprio
);
2556 * Must be called with the queue_lock held.
2558 static int cfqq_process_refs(struct cfq_queue
*cfqq
)
2560 int process_refs
, io_refs
;
2562 io_refs
= cfqq
->allocated
[READ
] + cfqq
->allocated
[WRITE
];
2563 process_refs
= cfqq
->ref
- io_refs
;
2564 BUG_ON(process_refs
< 0);
2565 return process_refs
;
2568 static void cfq_setup_merge(struct cfq_queue
*cfqq
, struct cfq_queue
*new_cfqq
)
2570 int process_refs
, new_process_refs
;
2571 struct cfq_queue
*__cfqq
;
2574 * If there are no process references on the new_cfqq, then it is
2575 * unsafe to follow the ->new_cfqq chain as other cfqq's in the
2576 * chain may have dropped their last reference (not just their
2577 * last process reference).
2579 if (!cfqq_process_refs(new_cfqq
))
2582 /* Avoid a circular list and skip interim queue merges */
2583 while ((__cfqq
= new_cfqq
->new_cfqq
)) {
2589 process_refs
= cfqq_process_refs(cfqq
);
2590 new_process_refs
= cfqq_process_refs(new_cfqq
);
2592 * If the process for the cfqq has gone away, there is no
2593 * sense in merging the queues.
2595 if (process_refs
== 0 || new_process_refs
== 0)
2599 * Merge in the direction of the lesser amount of work.
2601 if (new_process_refs
>= process_refs
) {
2602 cfqq
->new_cfqq
= new_cfqq
;
2603 new_cfqq
->ref
+= process_refs
;
2605 new_cfqq
->new_cfqq
= cfqq
;
2606 cfqq
->ref
+= new_process_refs
;
2610 static enum wl_type_t
cfq_choose_wl_type(struct cfq_data
*cfqd
,
2611 struct cfq_group
*cfqg
, enum wl_class_t wl_class
)
2613 struct cfq_queue
*queue
;
2615 bool key_valid
= false;
2616 unsigned long lowest_key
= 0;
2617 enum wl_type_t cur_best
= SYNC_NOIDLE_WORKLOAD
;
2619 for (i
= 0; i
<= SYNC_WORKLOAD
; ++i
) {
2620 /* select the one with lowest rb_key */
2621 queue
= cfq_rb_first(st_for(cfqg
, wl_class
, i
));
2623 (!key_valid
|| time_before(queue
->rb_key
, lowest_key
))) {
2624 lowest_key
= queue
->rb_key
;
2634 choose_wl_class_and_type(struct cfq_data
*cfqd
, struct cfq_group
*cfqg
)
2638 struct cfq_rb_root
*st
;
2639 unsigned group_slice
;
2640 enum wl_class_t original_class
= cfqd
->serving_wl_class
;
2642 /* Choose next priority. RT > BE > IDLE */
2643 if (cfq_group_busy_queues_wl(RT_WORKLOAD
, cfqd
, cfqg
))
2644 cfqd
->serving_wl_class
= RT_WORKLOAD
;
2645 else if (cfq_group_busy_queues_wl(BE_WORKLOAD
, cfqd
, cfqg
))
2646 cfqd
->serving_wl_class
= BE_WORKLOAD
;
2648 cfqd
->serving_wl_class
= IDLE_WORKLOAD
;
2649 cfqd
->workload_expires
= jiffies
+ 1;
2653 if (original_class
!= cfqd
->serving_wl_class
)
2657 * For RT and BE, we have to choose also the type
2658 * (SYNC, SYNC_NOIDLE, ASYNC), and to compute a workload
2661 st
= st_for(cfqg
, cfqd
->serving_wl_class
, cfqd
->serving_wl_type
);
2665 * check workload expiration, and that we still have other queues ready
2667 if (count
&& !time_after(jiffies
, cfqd
->workload_expires
))
2671 /* otherwise select new workload type */
2672 cfqd
->serving_wl_type
= cfq_choose_wl_type(cfqd
, cfqg
,
2673 cfqd
->serving_wl_class
);
2674 st
= st_for(cfqg
, cfqd
->serving_wl_class
, cfqd
->serving_wl_type
);
2678 * the workload slice is computed as a fraction of target latency
2679 * proportional to the number of queues in that workload, over
2680 * all the queues in the same priority class
2682 group_slice
= cfq_group_slice(cfqd
, cfqg
);
2684 slice
= group_slice
* count
/
2685 max_t(unsigned, cfqg
->busy_queues_avg
[cfqd
->serving_wl_class
],
2686 cfq_group_busy_queues_wl(cfqd
->serving_wl_class
, cfqd
,
2689 if (cfqd
->serving_wl_type
== ASYNC_WORKLOAD
) {
2693 * Async queues are currently system wide. Just taking
2694 * proportion of queues with-in same group will lead to higher
2695 * async ratio system wide as generally root group is going
2696 * to have higher weight. A more accurate thing would be to
2697 * calculate system wide asnc/sync ratio.
2699 tmp
= cfqd
->cfq_target_latency
*
2700 cfqg_busy_async_queues(cfqd
, cfqg
);
2701 tmp
= tmp
/cfqd
->busy_queues
;
2702 slice
= min_t(unsigned, slice
, tmp
);
2704 /* async workload slice is scaled down according to
2705 * the sync/async slice ratio. */
2706 slice
= slice
* cfqd
->cfq_slice
[0] / cfqd
->cfq_slice
[1];
2708 /* sync workload slice is at least 2 * cfq_slice_idle */
2709 slice
= max(slice
, 2 * cfqd
->cfq_slice_idle
);
2711 slice
= max_t(unsigned, slice
, CFQ_MIN_TT
);
2712 cfq_log(cfqd
, "workload slice:%d", slice
);
2713 cfqd
->workload_expires
= jiffies
+ slice
;
2716 static struct cfq_group
*cfq_get_next_cfqg(struct cfq_data
*cfqd
)
2718 struct cfq_rb_root
*st
= &cfqd
->grp_service_tree
;
2719 struct cfq_group
*cfqg
;
2721 if (RB_EMPTY_ROOT(&st
->rb
))
2723 cfqg
= cfq_rb_first_group(st
);
2724 update_min_vdisktime(st
);
2728 static void cfq_choose_cfqg(struct cfq_data
*cfqd
)
2730 struct cfq_group
*cfqg
= cfq_get_next_cfqg(cfqd
);
2732 cfqd
->serving_group
= cfqg
;
2734 /* Restore the workload type data */
2735 if (cfqg
->saved_wl_slice
) {
2736 cfqd
->workload_expires
= jiffies
+ cfqg
->saved_wl_slice
;
2737 cfqd
->serving_wl_type
= cfqg
->saved_wl_type
;
2738 cfqd
->serving_wl_class
= cfqg
->saved_wl_class
;
2740 cfqd
->workload_expires
= jiffies
- 1;
2742 choose_wl_class_and_type(cfqd
, cfqg
);
2746 * Select a queue for service. If we have a current active queue,
2747 * check whether to continue servicing it, or retrieve and set a new one.
2749 static struct cfq_queue
*cfq_select_queue(struct cfq_data
*cfqd
)
2751 struct cfq_queue
*cfqq
, *new_cfqq
= NULL
;
2753 cfqq
= cfqd
->active_queue
;
2757 if (!cfqd
->rq_queued
)
2761 * We were waiting for group to get backlogged. Expire the queue
2763 if (cfq_cfqq_wait_busy(cfqq
) && !RB_EMPTY_ROOT(&cfqq
->sort_list
))
2767 * The active queue has run out of time, expire it and select new.
2769 if (cfq_slice_used(cfqq
) && !cfq_cfqq_must_dispatch(cfqq
)) {
2771 * If slice had not expired at the completion of last request
2772 * we might not have turned on wait_busy flag. Don't expire
2773 * the queue yet. Allow the group to get backlogged.
2775 * The very fact that we have used the slice, that means we
2776 * have been idling all along on this queue and it should be
2777 * ok to wait for this request to complete.
2779 if (cfqq
->cfqg
->nr_cfqq
== 1 && RB_EMPTY_ROOT(&cfqq
->sort_list
)
2780 && cfqq
->dispatched
&& cfq_should_idle(cfqd
, cfqq
)) {
2784 goto check_group_idle
;
2788 * The active queue has requests and isn't expired, allow it to
2791 if (!RB_EMPTY_ROOT(&cfqq
->sort_list
))
2795 * If another queue has a request waiting within our mean seek
2796 * distance, let it run. The expire code will check for close
2797 * cooperators and put the close queue at the front of the service
2798 * tree. If possible, merge the expiring queue with the new cfqq.
2800 new_cfqq
= cfq_close_cooperator(cfqd
, cfqq
);
2802 if (!cfqq
->new_cfqq
)
2803 cfq_setup_merge(cfqq
, new_cfqq
);
2808 * No requests pending. If the active queue still has requests in
2809 * flight or is idling for a new request, allow either of these
2810 * conditions to happen (or time out) before selecting a new queue.
2812 if (timer_pending(&cfqd
->idle_slice_timer
)) {
2818 * This is a deep seek queue, but the device is much faster than
2819 * the queue can deliver, don't idle
2821 if (CFQQ_SEEKY(cfqq
) && cfq_cfqq_idle_window(cfqq
) &&
2822 (cfq_cfqq_slice_new(cfqq
) ||
2823 (cfqq
->slice_end
- jiffies
> jiffies
- cfqq
->slice_start
))) {
2824 cfq_clear_cfqq_deep(cfqq
);
2825 cfq_clear_cfqq_idle_window(cfqq
);
2828 if (cfqq
->dispatched
&& cfq_should_idle(cfqd
, cfqq
)) {
2834 * If group idle is enabled and there are requests dispatched from
2835 * this group, wait for requests to complete.
2838 if (cfqd
->cfq_group_idle
&& cfqq
->cfqg
->nr_cfqq
== 1 &&
2839 cfqq
->cfqg
->dispatched
&&
2840 !cfq_io_thinktime_big(cfqd
, &cfqq
->cfqg
->ttime
, true)) {
2846 cfq_slice_expired(cfqd
, 0);
2849 * Current queue expired. Check if we have to switch to a new
2853 cfq_choose_cfqg(cfqd
);
2855 cfqq
= cfq_set_active_queue(cfqd
, new_cfqq
);
2860 static int __cfq_forced_dispatch_cfqq(struct cfq_queue
*cfqq
)
2864 while (cfqq
->next_rq
) {
2865 cfq_dispatch_insert(cfqq
->cfqd
->queue
, cfqq
->next_rq
);
2869 BUG_ON(!list_empty(&cfqq
->fifo
));
2871 /* By default cfqq is not expired if it is empty. Do it explicitly */
2872 __cfq_slice_expired(cfqq
->cfqd
, cfqq
, 0);
2877 * Drain our current requests. Used for barriers and when switching
2878 * io schedulers on-the-fly.
2880 static int cfq_forced_dispatch(struct cfq_data
*cfqd
)
2882 struct cfq_queue
*cfqq
;
2885 /* Expire the timeslice of the current active queue first */
2886 cfq_slice_expired(cfqd
, 0);
2887 while ((cfqq
= cfq_get_next_queue_forced(cfqd
)) != NULL
) {
2888 __cfq_set_active_queue(cfqd
, cfqq
);
2889 dispatched
+= __cfq_forced_dispatch_cfqq(cfqq
);
2892 BUG_ON(cfqd
->busy_queues
);
2894 cfq_log(cfqd
, "forced_dispatch=%d", dispatched
);
2898 static inline bool cfq_slice_used_soon(struct cfq_data
*cfqd
,
2899 struct cfq_queue
*cfqq
)
2901 /* the queue hasn't finished any request, can't estimate */
2902 if (cfq_cfqq_slice_new(cfqq
))
2904 if (time_after(jiffies
+ cfqd
->cfq_slice_idle
* cfqq
->dispatched
,
2911 static bool cfq_may_dispatch(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
2913 unsigned int max_dispatch
;
2916 * Drain async requests before we start sync IO
2918 if (cfq_should_idle(cfqd
, cfqq
) && cfqd
->rq_in_flight
[BLK_RW_ASYNC
])
2922 * If this is an async queue and we have sync IO in flight, let it wait
2924 if (cfqd
->rq_in_flight
[BLK_RW_SYNC
] && !cfq_cfqq_sync(cfqq
))
2927 max_dispatch
= max_t(unsigned int, cfqd
->cfq_quantum
/ 2, 1);
2928 if (cfq_class_idle(cfqq
))
2932 * Does this cfqq already have too much IO in flight?
2934 if (cfqq
->dispatched
>= max_dispatch
) {
2935 bool promote_sync
= false;
2937 * idle queue must always only have a single IO in flight
2939 if (cfq_class_idle(cfqq
))
2943 * If there is only one sync queue
2944 * we can ignore async queue here and give the sync
2945 * queue no dispatch limit. The reason is a sync queue can
2946 * preempt async queue, limiting the sync queue doesn't make
2947 * sense. This is useful for aiostress test.
2949 if (cfq_cfqq_sync(cfqq
) && cfqd
->busy_sync_queues
== 1)
2950 promote_sync
= true;
2953 * We have other queues, don't allow more IO from this one
2955 if (cfqd
->busy_queues
> 1 && cfq_slice_used_soon(cfqd
, cfqq
) &&
2960 * Sole queue user, no limit
2962 if (cfqd
->busy_queues
== 1 || promote_sync
)
2966 * Normally we start throttling cfqq when cfq_quantum/2
2967 * requests have been dispatched. But we can drive
2968 * deeper queue depths at the beginning of slice
2969 * subjected to upper limit of cfq_quantum.
2971 max_dispatch
= cfqd
->cfq_quantum
;
2975 * Async queues must wait a bit before being allowed dispatch.
2976 * We also ramp up the dispatch depth gradually for async IO,
2977 * based on the last sync IO we serviced
2979 if (!cfq_cfqq_sync(cfqq
) && cfqd
->cfq_latency
) {
2980 unsigned long last_sync
= jiffies
- cfqd
->last_delayed_sync
;
2983 depth
= last_sync
/ cfqd
->cfq_slice
[1];
2984 if (!depth
&& !cfqq
->dispatched
)
2986 if (depth
< max_dispatch
)
2987 max_dispatch
= depth
;
2991 * If we're below the current max, allow a dispatch
2993 return cfqq
->dispatched
< max_dispatch
;
2997 * Dispatch a request from cfqq, moving them to the request queue
3000 static bool cfq_dispatch_request(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
3004 BUG_ON(RB_EMPTY_ROOT(&cfqq
->sort_list
));
3006 if (!cfq_may_dispatch(cfqd
, cfqq
))
3010 * follow expired path, else get first next available
3012 rq
= cfq_check_fifo(cfqq
);
3017 * insert request into driver dispatch list
3019 cfq_dispatch_insert(cfqd
->queue
, rq
);
3021 if (!cfqd
->active_cic
) {
3022 struct cfq_io_cq
*cic
= RQ_CIC(rq
);
3024 atomic_long_inc(&cic
->icq
.ioc
->refcount
);
3025 cfqd
->active_cic
= cic
;
3032 * Find the cfqq that we need to service and move a request from that to the
3035 static int cfq_dispatch_requests(struct request_queue
*q
, int force
)
3037 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
3038 struct cfq_queue
*cfqq
;
3040 if (!cfqd
->busy_queues
)
3043 if (unlikely(force
))
3044 return cfq_forced_dispatch(cfqd
);
3046 cfqq
= cfq_select_queue(cfqd
);
3051 * Dispatch a request from this cfqq, if it is allowed
3053 if (!cfq_dispatch_request(cfqd
, cfqq
))
3056 cfqq
->slice_dispatch
++;
3057 cfq_clear_cfqq_must_dispatch(cfqq
);
3060 * expire an async queue immediately if it has used up its slice. idle
3061 * queue always expire after 1 dispatch round.
3063 if (cfqd
->busy_queues
> 1 && ((!cfq_cfqq_sync(cfqq
) &&
3064 cfqq
->slice_dispatch
>= cfq_prio_to_maxrq(cfqd
, cfqq
)) ||
3065 cfq_class_idle(cfqq
))) {
3066 cfqq
->slice_end
= jiffies
+ 1;
3067 cfq_slice_expired(cfqd
, 0);
3070 cfq_log_cfqq(cfqd
, cfqq
, "dispatched a request");
3075 * task holds one reference to the queue, dropped when task exits. each rq
3076 * in-flight on this queue also holds a reference, dropped when rq is freed.
3078 * Each cfq queue took a reference on the parent group. Drop it now.
3079 * queue lock must be held here.
3081 static void cfq_put_queue(struct cfq_queue
*cfqq
)
3083 struct cfq_data
*cfqd
= cfqq
->cfqd
;
3084 struct cfq_group
*cfqg
;
3086 BUG_ON(cfqq
->ref
<= 0);
3092 cfq_log_cfqq(cfqd
, cfqq
, "put_queue");
3093 BUG_ON(rb_first(&cfqq
->sort_list
));
3094 BUG_ON(cfqq
->allocated
[READ
] + cfqq
->allocated
[WRITE
]);
3097 if (unlikely(cfqd
->active_queue
== cfqq
)) {
3098 __cfq_slice_expired(cfqd
, cfqq
, 0);
3099 cfq_schedule_dispatch(cfqd
);
3102 BUG_ON(cfq_cfqq_on_rr(cfqq
));
3103 kmem_cache_free(cfq_pool
, cfqq
);
3107 static void cfq_put_cooperator(struct cfq_queue
*cfqq
)
3109 struct cfq_queue
*__cfqq
, *next
;
3112 * If this queue was scheduled to merge with another queue, be
3113 * sure to drop the reference taken on that queue (and others in
3114 * the merge chain). See cfq_setup_merge and cfq_merge_cfqqs.
3116 __cfqq
= cfqq
->new_cfqq
;
3118 if (__cfqq
== cfqq
) {
3119 WARN(1, "cfqq->new_cfqq loop detected\n");
3122 next
= __cfqq
->new_cfqq
;
3123 cfq_put_queue(__cfqq
);
3128 static void cfq_exit_cfqq(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
3130 if (unlikely(cfqq
== cfqd
->active_queue
)) {
3131 __cfq_slice_expired(cfqd
, cfqq
, 0);
3132 cfq_schedule_dispatch(cfqd
);
3135 cfq_put_cooperator(cfqq
);
3137 cfq_put_queue(cfqq
);
3140 static void cfq_init_icq(struct io_cq
*icq
)
3142 struct cfq_io_cq
*cic
= icq_to_cic(icq
);
3144 cic
->ttime
.last_end_request
= jiffies
;
3147 static void cfq_exit_icq(struct io_cq
*icq
)
3149 struct cfq_io_cq
*cic
= icq_to_cic(icq
);
3150 struct cfq_data
*cfqd
= cic_to_cfqd(cic
);
3152 if (cic
->cfqq
[BLK_RW_ASYNC
]) {
3153 cfq_exit_cfqq(cfqd
, cic
->cfqq
[BLK_RW_ASYNC
]);
3154 cic
->cfqq
[BLK_RW_ASYNC
] = NULL
;
3157 if (cic
->cfqq
[BLK_RW_SYNC
]) {
3158 cfq_exit_cfqq(cfqd
, cic
->cfqq
[BLK_RW_SYNC
]);
3159 cic
->cfqq
[BLK_RW_SYNC
] = NULL
;
3163 static void cfq_init_prio_data(struct cfq_queue
*cfqq
, struct cfq_io_cq
*cic
)
3165 struct task_struct
*tsk
= current
;
3168 if (!cfq_cfqq_prio_changed(cfqq
))
3171 ioprio_class
= IOPRIO_PRIO_CLASS(cic
->ioprio
);
3172 switch (ioprio_class
) {
3174 printk(KERN_ERR
"cfq: bad prio %x\n", ioprio_class
);
3175 case IOPRIO_CLASS_NONE
:
3177 * no prio set, inherit CPU scheduling settings
3179 cfqq
->ioprio
= task_nice_ioprio(tsk
);
3180 cfqq
->ioprio_class
= task_nice_ioclass(tsk
);
3182 case IOPRIO_CLASS_RT
:
3183 cfqq
->ioprio
= IOPRIO_PRIO_DATA(cic
->ioprio
);
3184 cfqq
->ioprio_class
= IOPRIO_CLASS_RT
;
3186 case IOPRIO_CLASS_BE
:
3187 cfqq
->ioprio
= IOPRIO_PRIO_DATA(cic
->ioprio
);
3188 cfqq
->ioprio_class
= IOPRIO_CLASS_BE
;
3190 case IOPRIO_CLASS_IDLE
:
3191 cfqq
->ioprio_class
= IOPRIO_CLASS_IDLE
;
3193 cfq_clear_cfqq_idle_window(cfqq
);
3198 * keep track of original prio settings in case we have to temporarily
3199 * elevate the priority of this queue
3201 cfqq
->org_ioprio
= cfqq
->ioprio
;
3202 cfq_clear_cfqq_prio_changed(cfqq
);
3205 static void check_ioprio_changed(struct cfq_io_cq
*cic
, struct bio
*bio
)
3207 int ioprio
= cic
->icq
.ioc
->ioprio
;
3208 struct cfq_data
*cfqd
= cic_to_cfqd(cic
);
3209 struct cfq_queue
*cfqq
;
3212 * Check whether ioprio has changed. The condition may trigger
3213 * spuriously on a newly created cic but there's no harm.
3215 if (unlikely(!cfqd
) || likely(cic
->ioprio
== ioprio
))
3218 cfqq
= cic
->cfqq
[BLK_RW_ASYNC
];
3220 struct cfq_queue
*new_cfqq
;
3221 new_cfqq
= cfq_get_queue(cfqd
, BLK_RW_ASYNC
, cic
, bio
,
3224 cic
->cfqq
[BLK_RW_ASYNC
] = new_cfqq
;
3225 cfq_put_queue(cfqq
);
3229 cfqq
= cic
->cfqq
[BLK_RW_SYNC
];
3231 cfq_mark_cfqq_prio_changed(cfqq
);
3233 cic
->ioprio
= ioprio
;
3236 static void cfq_init_cfqq(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
3237 pid_t pid
, bool is_sync
)
3239 RB_CLEAR_NODE(&cfqq
->rb_node
);
3240 RB_CLEAR_NODE(&cfqq
->p_node
);
3241 INIT_LIST_HEAD(&cfqq
->fifo
);
3246 cfq_mark_cfqq_prio_changed(cfqq
);
3249 if (!cfq_class_idle(cfqq
))
3250 cfq_mark_cfqq_idle_window(cfqq
);
3251 cfq_mark_cfqq_sync(cfqq
);
3256 #ifdef CONFIG_CFQ_GROUP_IOSCHED
3257 static void check_blkcg_changed(struct cfq_io_cq
*cic
, struct bio
*bio
)
3259 struct cfq_data
*cfqd
= cic_to_cfqd(cic
);
3260 struct cfq_queue
*sync_cfqq
;
3264 id
= bio_blkcg(bio
)->id
;
3268 * Check whether blkcg has changed. The condition may trigger
3269 * spuriously on a newly created cic but there's no harm.
3271 if (unlikely(!cfqd
) || likely(cic
->blkcg_id
== id
))
3274 sync_cfqq
= cic_to_cfqq(cic
, 1);
3277 * Drop reference to sync queue. A new sync queue will be
3278 * assigned in new group upon arrival of a fresh request.
3280 cfq_log_cfqq(cfqd
, sync_cfqq
, "changed cgroup");
3281 cic_set_cfqq(cic
, NULL
, 1);
3282 cfq_put_queue(sync_cfqq
);
3288 static inline void check_blkcg_changed(struct cfq_io_cq
*cic
, struct bio
*bio
) { }
3289 #endif /* CONFIG_CFQ_GROUP_IOSCHED */
3291 static struct cfq_queue
*
3292 cfq_find_alloc_queue(struct cfq_data
*cfqd
, bool is_sync
, struct cfq_io_cq
*cic
,
3293 struct bio
*bio
, gfp_t gfp_mask
)
3295 struct blkcg
*blkcg
;
3296 struct cfq_queue
*cfqq
, *new_cfqq
= NULL
;
3297 struct cfq_group
*cfqg
;
3302 blkcg
= bio_blkcg(bio
);
3303 cfqg
= cfq_lookup_create_cfqg(cfqd
, blkcg
);
3304 cfqq
= cic_to_cfqq(cic
, is_sync
);
3307 * Always try a new alloc if we fell back to the OOM cfqq
3308 * originally, since it should just be a temporary situation.
3310 if (!cfqq
|| cfqq
== &cfqd
->oom_cfqq
) {
3315 } else if (gfp_mask
& __GFP_WAIT
) {
3317 spin_unlock_irq(cfqd
->queue
->queue_lock
);
3318 new_cfqq
= kmem_cache_alloc_node(cfq_pool
,
3319 gfp_mask
| __GFP_ZERO
,
3321 spin_lock_irq(cfqd
->queue
->queue_lock
);
3325 cfqq
= kmem_cache_alloc_node(cfq_pool
,
3326 gfp_mask
| __GFP_ZERO
,
3331 cfq_init_cfqq(cfqd
, cfqq
, current
->pid
, is_sync
);
3332 cfq_init_prio_data(cfqq
, cic
);
3333 cfq_link_cfqq_cfqg(cfqq
, cfqg
);
3334 cfq_log_cfqq(cfqd
, cfqq
, "alloced");
3336 cfqq
= &cfqd
->oom_cfqq
;
3340 kmem_cache_free(cfq_pool
, new_cfqq
);
3346 static struct cfq_queue
**
3347 cfq_async_queue_prio(struct cfq_data
*cfqd
, int ioprio_class
, int ioprio
)
3349 switch (ioprio_class
) {
3350 case IOPRIO_CLASS_RT
:
3351 return &cfqd
->async_cfqq
[0][ioprio
];
3352 case IOPRIO_CLASS_NONE
:
3353 ioprio
= IOPRIO_NORM
;
3355 case IOPRIO_CLASS_BE
:
3356 return &cfqd
->async_cfqq
[1][ioprio
];
3357 case IOPRIO_CLASS_IDLE
:
3358 return &cfqd
->async_idle_cfqq
;
3364 static struct cfq_queue
*
3365 cfq_get_queue(struct cfq_data
*cfqd
, bool is_sync
, struct cfq_io_cq
*cic
,
3366 struct bio
*bio
, gfp_t gfp_mask
)
3368 const int ioprio_class
= IOPRIO_PRIO_CLASS(cic
->ioprio
);
3369 const int ioprio
= IOPRIO_PRIO_DATA(cic
->ioprio
);
3370 struct cfq_queue
**async_cfqq
= NULL
;
3371 struct cfq_queue
*cfqq
= NULL
;
3374 async_cfqq
= cfq_async_queue_prio(cfqd
, ioprio_class
, ioprio
);
3379 cfqq
= cfq_find_alloc_queue(cfqd
, is_sync
, cic
, bio
, gfp_mask
);
3382 * pin the queue now that it's allocated, scheduler exit will prune it
3384 if (!is_sync
&& !(*async_cfqq
)) {
3394 __cfq_update_io_thinktime(struct cfq_ttime
*ttime
, unsigned long slice_idle
)
3396 unsigned long elapsed
= jiffies
- ttime
->last_end_request
;
3397 elapsed
= min(elapsed
, 2UL * slice_idle
);
3399 ttime
->ttime_samples
= (7*ttime
->ttime_samples
+ 256) / 8;
3400 ttime
->ttime_total
= (7*ttime
->ttime_total
+ 256*elapsed
) / 8;
3401 ttime
->ttime_mean
= (ttime
->ttime_total
+ 128) / ttime
->ttime_samples
;
3405 cfq_update_io_thinktime(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
3406 struct cfq_io_cq
*cic
)
3408 if (cfq_cfqq_sync(cfqq
)) {
3409 __cfq_update_io_thinktime(&cic
->ttime
, cfqd
->cfq_slice_idle
);
3410 __cfq_update_io_thinktime(&cfqq
->service_tree
->ttime
,
3411 cfqd
->cfq_slice_idle
);
3413 #ifdef CONFIG_CFQ_GROUP_IOSCHED
3414 __cfq_update_io_thinktime(&cfqq
->cfqg
->ttime
, cfqd
->cfq_group_idle
);
3419 cfq_update_io_seektime(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
3423 sector_t n_sec
= blk_rq_sectors(rq
);
3424 if (cfqq
->last_request_pos
) {
3425 if (cfqq
->last_request_pos
< blk_rq_pos(rq
))
3426 sdist
= blk_rq_pos(rq
) - cfqq
->last_request_pos
;
3428 sdist
= cfqq
->last_request_pos
- blk_rq_pos(rq
);
3431 cfqq
->seek_history
<<= 1;
3432 if (blk_queue_nonrot(cfqd
->queue
))
3433 cfqq
->seek_history
|= (n_sec
< CFQQ_SECT_THR_NONROT
);
3435 cfqq
->seek_history
|= (sdist
> CFQQ_SEEK_THR
);
3439 * Disable idle window if the process thinks too long or seeks so much that
3443 cfq_update_idle_window(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
3444 struct cfq_io_cq
*cic
)
3446 int old_idle
, enable_idle
;
3449 * Don't idle for async or idle io prio class
3451 if (!cfq_cfqq_sync(cfqq
) || cfq_class_idle(cfqq
))
3454 enable_idle
= old_idle
= cfq_cfqq_idle_window(cfqq
);
3456 if (cfqq
->queued
[0] + cfqq
->queued
[1] >= 4)
3457 cfq_mark_cfqq_deep(cfqq
);
3459 if (cfqq
->next_rq
&& (cfqq
->next_rq
->cmd_flags
& REQ_NOIDLE
))
3461 else if (!atomic_read(&cic
->icq
.ioc
->active_ref
) ||
3462 !cfqd
->cfq_slice_idle
||
3463 (!cfq_cfqq_deep(cfqq
) && CFQQ_SEEKY(cfqq
)))
3465 else if (sample_valid(cic
->ttime
.ttime_samples
)) {
3466 if (cic
->ttime
.ttime_mean
> cfqd
->cfq_slice_idle
)
3472 if (old_idle
!= enable_idle
) {
3473 cfq_log_cfqq(cfqd
, cfqq
, "idle=%d", enable_idle
);
3475 cfq_mark_cfqq_idle_window(cfqq
);
3477 cfq_clear_cfqq_idle_window(cfqq
);
3482 * Check if new_cfqq should preempt the currently active queue. Return 0 for
3483 * no or if we aren't sure, a 1 will cause a preempt.
3486 cfq_should_preempt(struct cfq_data
*cfqd
, struct cfq_queue
*new_cfqq
,
3489 struct cfq_queue
*cfqq
;
3491 cfqq
= cfqd
->active_queue
;
3495 if (cfq_class_idle(new_cfqq
))
3498 if (cfq_class_idle(cfqq
))
3502 * Don't allow a non-RT request to preempt an ongoing RT cfqq timeslice.
3504 if (cfq_class_rt(cfqq
) && !cfq_class_rt(new_cfqq
))
3508 * if the new request is sync, but the currently running queue is
3509 * not, let the sync request have priority.
3511 if (rq_is_sync(rq
) && !cfq_cfqq_sync(cfqq
))
3514 if (new_cfqq
->cfqg
!= cfqq
->cfqg
)
3517 if (cfq_slice_used(cfqq
))
3520 /* Allow preemption only if we are idling on sync-noidle tree */
3521 if (cfqd
->serving_wl_type
== SYNC_NOIDLE_WORKLOAD
&&
3522 cfqq_type(new_cfqq
) == SYNC_NOIDLE_WORKLOAD
&&
3523 new_cfqq
->service_tree
->count
== 2 &&
3524 RB_EMPTY_ROOT(&cfqq
->sort_list
))
3528 * So both queues are sync. Let the new request get disk time if
3529 * it's a metadata request and the current queue is doing regular IO.
3531 if ((rq
->cmd_flags
& REQ_PRIO
) && !cfqq
->prio_pending
)
3535 * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice.
3537 if (cfq_class_rt(new_cfqq
) && !cfq_class_rt(cfqq
))
3540 /* An idle queue should not be idle now for some reason */
3541 if (RB_EMPTY_ROOT(&cfqq
->sort_list
) && !cfq_should_idle(cfqd
, cfqq
))
3544 if (!cfqd
->active_cic
|| !cfq_cfqq_wait_request(cfqq
))
3548 * if this request is as-good as one we would expect from the
3549 * current cfqq, let it preempt
3551 if (cfq_rq_close(cfqd
, cfqq
, rq
))
3558 * cfqq preempts the active queue. if we allowed preempt with no slice left,
3559 * let it have half of its nominal slice.
3561 static void cfq_preempt_queue(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
3563 enum wl_type_t old_type
= cfqq_type(cfqd
->active_queue
);
3565 cfq_log_cfqq(cfqd
, cfqq
, "preempt");
3566 cfq_slice_expired(cfqd
, 1);
3569 * workload type is changed, don't save slice, otherwise preempt
3572 if (old_type
!= cfqq_type(cfqq
))
3573 cfqq
->cfqg
->saved_wl_slice
= 0;
3576 * Put the new queue at the front of the of the current list,
3577 * so we know that it will be selected next.
3579 BUG_ON(!cfq_cfqq_on_rr(cfqq
));
3581 cfq_service_tree_add(cfqd
, cfqq
, 1);
3583 cfqq
->slice_end
= 0;
3584 cfq_mark_cfqq_slice_new(cfqq
);
3588 * Called when a new fs request (rq) is added (to cfqq). Check if there's
3589 * something we should do about it
3592 cfq_rq_enqueued(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
3595 struct cfq_io_cq
*cic
= RQ_CIC(rq
);
3598 if (rq
->cmd_flags
& REQ_PRIO
)
3599 cfqq
->prio_pending
++;
3601 cfq_update_io_thinktime(cfqd
, cfqq
, cic
);
3602 cfq_update_io_seektime(cfqd
, cfqq
, rq
);
3603 cfq_update_idle_window(cfqd
, cfqq
, cic
);
3605 cfqq
->last_request_pos
= blk_rq_pos(rq
) + blk_rq_sectors(rq
);
3607 if (cfqq
== cfqd
->active_queue
) {
3609 * Remember that we saw a request from this process, but
3610 * don't start queuing just yet. Otherwise we risk seeing lots
3611 * of tiny requests, because we disrupt the normal plugging
3612 * and merging. If the request is already larger than a single
3613 * page, let it rip immediately. For that case we assume that
3614 * merging is already done. Ditto for a busy system that
3615 * has other work pending, don't risk delaying until the
3616 * idle timer unplug to continue working.
3618 if (cfq_cfqq_wait_request(cfqq
)) {
3619 if (blk_rq_bytes(rq
) > PAGE_CACHE_SIZE
||
3620 cfqd
->busy_queues
> 1) {
3621 cfq_del_timer(cfqd
, cfqq
);
3622 cfq_clear_cfqq_wait_request(cfqq
);
3623 __blk_run_queue(cfqd
->queue
);
3625 cfqg_stats_update_idle_time(cfqq
->cfqg
);
3626 cfq_mark_cfqq_must_dispatch(cfqq
);
3629 } else if (cfq_should_preempt(cfqd
, cfqq
, rq
)) {
3631 * not the active queue - expire current slice if it is
3632 * idle and has expired it's mean thinktime or this new queue
3633 * has some old slice time left and is of higher priority or
3634 * this new queue is RT and the current one is BE
3636 cfq_preempt_queue(cfqd
, cfqq
);
3637 __blk_run_queue(cfqd
->queue
);
3641 static void cfq_insert_request(struct request_queue
*q
, struct request
*rq
)
3643 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
3644 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
3646 cfq_log_cfqq(cfqd
, cfqq
, "insert_request");
3647 cfq_init_prio_data(cfqq
, RQ_CIC(rq
));
3649 rq_set_fifo_time(rq
, jiffies
+ cfqd
->cfq_fifo_expire
[rq_is_sync(rq
)]);
3650 list_add_tail(&rq
->queuelist
, &cfqq
->fifo
);
3652 cfqg_stats_update_io_add(RQ_CFQG(rq
), cfqd
->serving_group
,
3654 cfq_rq_enqueued(cfqd
, cfqq
, rq
);
3658 * Update hw_tag based on peak queue depth over 50 samples under
3661 static void cfq_update_hw_tag(struct cfq_data
*cfqd
)
3663 struct cfq_queue
*cfqq
= cfqd
->active_queue
;
3665 if (cfqd
->rq_in_driver
> cfqd
->hw_tag_est_depth
)
3666 cfqd
->hw_tag_est_depth
= cfqd
->rq_in_driver
;
3668 if (cfqd
->hw_tag
== 1)
3671 if (cfqd
->rq_queued
<= CFQ_HW_QUEUE_MIN
&&
3672 cfqd
->rq_in_driver
<= CFQ_HW_QUEUE_MIN
)
3676 * If active queue hasn't enough requests and can idle, cfq might not
3677 * dispatch sufficient requests to hardware. Don't zero hw_tag in this
3680 if (cfqq
&& cfq_cfqq_idle_window(cfqq
) &&
3681 cfqq
->dispatched
+ cfqq
->queued
[0] + cfqq
->queued
[1] <
3682 CFQ_HW_QUEUE_MIN
&& cfqd
->rq_in_driver
< CFQ_HW_QUEUE_MIN
)
3685 if (cfqd
->hw_tag_samples
++ < 50)
3688 if (cfqd
->hw_tag_est_depth
>= CFQ_HW_QUEUE_MIN
)
3694 static bool cfq_should_wait_busy(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
3696 struct cfq_io_cq
*cic
= cfqd
->active_cic
;
3698 /* If the queue already has requests, don't wait */
3699 if (!RB_EMPTY_ROOT(&cfqq
->sort_list
))
3702 /* If there are other queues in the group, don't wait */
3703 if (cfqq
->cfqg
->nr_cfqq
> 1)
3706 /* the only queue in the group, but think time is big */
3707 if (cfq_io_thinktime_big(cfqd
, &cfqq
->cfqg
->ttime
, true))
3710 if (cfq_slice_used(cfqq
))
3713 /* if slice left is less than think time, wait busy */
3714 if (cic
&& sample_valid(cic
->ttime
.ttime_samples
)
3715 && (cfqq
->slice_end
- jiffies
< cic
->ttime
.ttime_mean
))
3719 * If think times is less than a jiffy than ttime_mean=0 and above
3720 * will not be true. It might happen that slice has not expired yet
3721 * but will expire soon (4-5 ns) during select_queue(). To cover the
3722 * case where think time is less than a jiffy, mark the queue wait
3723 * busy if only 1 jiffy is left in the slice.
3725 if (cfqq
->slice_end
- jiffies
== 1)
3731 static void cfq_completed_request(struct request_queue
*q
, struct request
*rq
)
3733 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
3734 struct cfq_data
*cfqd
= cfqq
->cfqd
;
3735 const int sync
= rq_is_sync(rq
);
3739 cfq_log_cfqq(cfqd
, cfqq
, "complete rqnoidle %d",
3740 !!(rq
->cmd_flags
& REQ_NOIDLE
));
3742 cfq_update_hw_tag(cfqd
);
3744 WARN_ON(!cfqd
->rq_in_driver
);
3745 WARN_ON(!cfqq
->dispatched
);
3746 cfqd
->rq_in_driver
--;
3748 (RQ_CFQG(rq
))->dispatched
--;
3749 cfqg_stats_update_completion(cfqq
->cfqg
, rq_start_time_ns(rq
),
3750 rq_io_start_time_ns(rq
), rq
->cmd_flags
);
3752 cfqd
->rq_in_flight
[cfq_cfqq_sync(cfqq
)]--;
3755 struct cfq_rb_root
*st
;
3757 RQ_CIC(rq
)->ttime
.last_end_request
= now
;
3759 if (cfq_cfqq_on_rr(cfqq
))
3760 st
= cfqq
->service_tree
;
3762 st
= st_for(cfqq
->cfqg
, cfqq_class(cfqq
),
3765 st
->ttime
.last_end_request
= now
;
3766 if (!time_after(rq
->start_time
+ cfqd
->cfq_fifo_expire
[1], now
))
3767 cfqd
->last_delayed_sync
= now
;
3770 #ifdef CONFIG_CFQ_GROUP_IOSCHED
3771 cfqq
->cfqg
->ttime
.last_end_request
= now
;
3775 * If this is the active queue, check if it needs to be expired,
3776 * or if we want to idle in case it has no pending requests.
3778 if (cfqd
->active_queue
== cfqq
) {
3779 const bool cfqq_empty
= RB_EMPTY_ROOT(&cfqq
->sort_list
);
3781 if (cfq_cfqq_slice_new(cfqq
)) {
3782 cfq_set_prio_slice(cfqd
, cfqq
);
3783 cfq_clear_cfqq_slice_new(cfqq
);
3787 * Should we wait for next request to come in before we expire
3790 if (cfq_should_wait_busy(cfqd
, cfqq
)) {
3791 unsigned long extend_sl
= cfqd
->cfq_slice_idle
;
3792 if (!cfqd
->cfq_slice_idle
)
3793 extend_sl
= cfqd
->cfq_group_idle
;
3794 cfqq
->slice_end
= jiffies
+ extend_sl
;
3795 cfq_mark_cfqq_wait_busy(cfqq
);
3796 cfq_log_cfqq(cfqd
, cfqq
, "will busy wait");
3800 * Idling is not enabled on:
3802 * - idle-priority queues
3804 * - queues with still some requests queued
3805 * - when there is a close cooperator
3807 if (cfq_slice_used(cfqq
) || cfq_class_idle(cfqq
))
3808 cfq_slice_expired(cfqd
, 1);
3809 else if (sync
&& cfqq_empty
&&
3810 !cfq_close_cooperator(cfqd
, cfqq
)) {
3811 cfq_arm_slice_timer(cfqd
);
3815 if (!cfqd
->rq_in_driver
)
3816 cfq_schedule_dispatch(cfqd
);
3819 static inline int __cfq_may_queue(struct cfq_queue
*cfqq
)
3821 if (cfq_cfqq_wait_request(cfqq
) && !cfq_cfqq_must_alloc_slice(cfqq
)) {
3822 cfq_mark_cfqq_must_alloc_slice(cfqq
);
3823 return ELV_MQUEUE_MUST
;
3826 return ELV_MQUEUE_MAY
;
3829 static int cfq_may_queue(struct request_queue
*q
, int rw
)
3831 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
3832 struct task_struct
*tsk
= current
;
3833 struct cfq_io_cq
*cic
;
3834 struct cfq_queue
*cfqq
;
3837 * don't force setup of a queue from here, as a call to may_queue
3838 * does not necessarily imply that a request actually will be queued.
3839 * so just lookup a possibly existing queue, or return 'may queue'
3842 cic
= cfq_cic_lookup(cfqd
, tsk
->io_context
);
3844 return ELV_MQUEUE_MAY
;
3846 cfqq
= cic_to_cfqq(cic
, rw_is_sync(rw
));
3848 cfq_init_prio_data(cfqq
, cic
);
3850 return __cfq_may_queue(cfqq
);
3853 return ELV_MQUEUE_MAY
;
3857 * queue lock held here
3859 static void cfq_put_request(struct request
*rq
)
3861 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
3864 const int rw
= rq_data_dir(rq
);
3866 BUG_ON(!cfqq
->allocated
[rw
]);
3867 cfqq
->allocated
[rw
]--;
3869 /* Put down rq reference on cfqg */
3870 cfqg_put(RQ_CFQG(rq
));
3871 rq
->elv
.priv
[0] = NULL
;
3872 rq
->elv
.priv
[1] = NULL
;
3874 cfq_put_queue(cfqq
);
3878 static struct cfq_queue
*
3879 cfq_merge_cfqqs(struct cfq_data
*cfqd
, struct cfq_io_cq
*cic
,
3880 struct cfq_queue
*cfqq
)
3882 cfq_log_cfqq(cfqd
, cfqq
, "merging with queue %p", cfqq
->new_cfqq
);
3883 cic_set_cfqq(cic
, cfqq
->new_cfqq
, 1);
3884 cfq_mark_cfqq_coop(cfqq
->new_cfqq
);
3885 cfq_put_queue(cfqq
);
3886 return cic_to_cfqq(cic
, 1);
3890 * Returns NULL if a new cfqq should be allocated, or the old cfqq if this
3891 * was the last process referring to said cfqq.
3893 static struct cfq_queue
*
3894 split_cfqq(struct cfq_io_cq
*cic
, struct cfq_queue
*cfqq
)
3896 if (cfqq_process_refs(cfqq
) == 1) {
3897 cfqq
->pid
= current
->pid
;
3898 cfq_clear_cfqq_coop(cfqq
);
3899 cfq_clear_cfqq_split_coop(cfqq
);
3903 cic_set_cfqq(cic
, NULL
, 1);
3905 cfq_put_cooperator(cfqq
);
3907 cfq_put_queue(cfqq
);
3911 * Allocate cfq data structures associated with this request.
3914 cfq_set_request(struct request_queue
*q
, struct request
*rq
, struct bio
*bio
,
3917 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
3918 struct cfq_io_cq
*cic
= icq_to_cic(rq
->elv
.icq
);
3919 const int rw
= rq_data_dir(rq
);
3920 const bool is_sync
= rq_is_sync(rq
);
3921 struct cfq_queue
*cfqq
;
3923 might_sleep_if(gfp_mask
& __GFP_WAIT
);
3925 spin_lock_irq(q
->queue_lock
);
3927 check_ioprio_changed(cic
, bio
);
3928 check_blkcg_changed(cic
, bio
);
3930 cfqq
= cic_to_cfqq(cic
, is_sync
);
3931 if (!cfqq
|| cfqq
== &cfqd
->oom_cfqq
) {
3932 cfqq
= cfq_get_queue(cfqd
, is_sync
, cic
, bio
, gfp_mask
);
3933 cic_set_cfqq(cic
, cfqq
, is_sync
);
3936 * If the queue was seeky for too long, break it apart.
3938 if (cfq_cfqq_coop(cfqq
) && cfq_cfqq_split_coop(cfqq
)) {
3939 cfq_log_cfqq(cfqd
, cfqq
, "breaking apart cfqq");
3940 cfqq
= split_cfqq(cic
, cfqq
);
3946 * Check to see if this queue is scheduled to merge with
3947 * another, closely cooperating queue. The merging of
3948 * queues happens here as it must be done in process context.
3949 * The reference on new_cfqq was taken in merge_cfqqs.
3952 cfqq
= cfq_merge_cfqqs(cfqd
, cic
, cfqq
);
3955 cfqq
->allocated
[rw
]++;
3958 cfqg_get(cfqq
->cfqg
);
3959 rq
->elv
.priv
[0] = cfqq
;
3960 rq
->elv
.priv
[1] = cfqq
->cfqg
;
3961 spin_unlock_irq(q
->queue_lock
);
3965 static void cfq_kick_queue(struct work_struct
*work
)
3967 struct cfq_data
*cfqd
=
3968 container_of(work
, struct cfq_data
, unplug_work
);
3969 struct request_queue
*q
= cfqd
->queue
;
3971 spin_lock_irq(q
->queue_lock
);
3972 __blk_run_queue(cfqd
->queue
);
3973 spin_unlock_irq(q
->queue_lock
);
3977 * Timer running if the active_queue is currently idling inside its time slice
3979 static void cfq_idle_slice_timer(unsigned long data
)
3981 struct cfq_data
*cfqd
= (struct cfq_data
*) data
;
3982 struct cfq_queue
*cfqq
;
3983 unsigned long flags
;
3986 cfq_log(cfqd
, "idle timer fired");
3988 spin_lock_irqsave(cfqd
->queue
->queue_lock
, flags
);
3990 cfqq
= cfqd
->active_queue
;
3995 * We saw a request before the queue expired, let it through
3997 if (cfq_cfqq_must_dispatch(cfqq
))
4003 if (cfq_slice_used(cfqq
))
4007 * only expire and reinvoke request handler, if there are
4008 * other queues with pending requests
4010 if (!cfqd
->busy_queues
)
4014 * not expired and it has a request pending, let it dispatch
4016 if (!RB_EMPTY_ROOT(&cfqq
->sort_list
))
4020 * Queue depth flag is reset only when the idle didn't succeed
4022 cfq_clear_cfqq_deep(cfqq
);
4025 cfq_slice_expired(cfqd
, timed_out
);
4027 cfq_schedule_dispatch(cfqd
);
4029 spin_unlock_irqrestore(cfqd
->queue
->queue_lock
, flags
);
4032 static void cfq_shutdown_timer_wq(struct cfq_data
*cfqd
)
4034 del_timer_sync(&cfqd
->idle_slice_timer
);
4035 cancel_work_sync(&cfqd
->unplug_work
);
4038 static void cfq_put_async_queues(struct cfq_data
*cfqd
)
4042 for (i
= 0; i
< IOPRIO_BE_NR
; i
++) {
4043 if (cfqd
->async_cfqq
[0][i
])
4044 cfq_put_queue(cfqd
->async_cfqq
[0][i
]);
4045 if (cfqd
->async_cfqq
[1][i
])
4046 cfq_put_queue(cfqd
->async_cfqq
[1][i
]);
4049 if (cfqd
->async_idle_cfqq
)
4050 cfq_put_queue(cfqd
->async_idle_cfqq
);
4053 static void cfq_exit_queue(struct elevator_queue
*e
)
4055 struct cfq_data
*cfqd
= e
->elevator_data
;
4056 struct request_queue
*q
= cfqd
->queue
;
4058 cfq_shutdown_timer_wq(cfqd
);
4060 spin_lock_irq(q
->queue_lock
);
4062 if (cfqd
->active_queue
)
4063 __cfq_slice_expired(cfqd
, cfqd
->active_queue
, 0);
4065 cfq_put_async_queues(cfqd
);
4067 spin_unlock_irq(q
->queue_lock
);
4069 cfq_shutdown_timer_wq(cfqd
);
4071 #ifdef CONFIG_CFQ_GROUP_IOSCHED
4072 blkcg_deactivate_policy(q
, &blkcg_policy_cfq
);
4074 kfree(cfqd
->root_group
);
4079 static int cfq_init_queue(struct request_queue
*q
)
4081 struct cfq_data
*cfqd
;
4082 struct blkcg_gq
*blkg __maybe_unused
;
4085 cfqd
= kmalloc_node(sizeof(*cfqd
), GFP_KERNEL
| __GFP_ZERO
, q
->node
);
4090 q
->elevator
->elevator_data
= cfqd
;
4092 /* Init root service tree */
4093 cfqd
->grp_service_tree
= CFQ_RB_ROOT
;
4095 /* Init root group and prefer root group over other groups by default */
4096 #ifdef CONFIG_CFQ_GROUP_IOSCHED
4097 ret
= blkcg_activate_policy(q
, &blkcg_policy_cfq
);
4101 cfqd
->root_group
= blkg_to_cfqg(q
->root_blkg
);
4104 cfqd
->root_group
= kzalloc_node(sizeof(*cfqd
->root_group
),
4105 GFP_KERNEL
, cfqd
->queue
->node
);
4106 if (!cfqd
->root_group
)
4109 cfq_init_cfqg_base(cfqd
->root_group
);
4111 cfqd
->root_group
->weight
= 2 * CFQ_WEIGHT_DEFAULT
;
4112 cfqd
->root_group
->leaf_weight
= 2 * CFQ_WEIGHT_DEFAULT
;
4115 * Not strictly needed (since RB_ROOT just clears the node and we
4116 * zeroed cfqd on alloc), but better be safe in case someone decides
4117 * to add magic to the rb code
4119 for (i
= 0; i
< CFQ_PRIO_LISTS
; i
++)
4120 cfqd
->prio_trees
[i
] = RB_ROOT
;
4123 * Our fallback cfqq if cfq_find_alloc_queue() runs into OOM issues.
4124 * Grab a permanent reference to it, so that the normal code flow
4125 * will not attempt to free it. oom_cfqq is linked to root_group
4126 * but shouldn't hold a reference as it'll never be unlinked. Lose
4127 * the reference from linking right away.
4129 cfq_init_cfqq(cfqd
, &cfqd
->oom_cfqq
, 1, 0);
4130 cfqd
->oom_cfqq
.ref
++;
4132 spin_lock_irq(q
->queue_lock
);
4133 cfq_link_cfqq_cfqg(&cfqd
->oom_cfqq
, cfqd
->root_group
);
4134 cfqg_put(cfqd
->root_group
);
4135 spin_unlock_irq(q
->queue_lock
);
4137 init_timer(&cfqd
->idle_slice_timer
);
4138 cfqd
->idle_slice_timer
.function
= cfq_idle_slice_timer
;
4139 cfqd
->idle_slice_timer
.data
= (unsigned long) cfqd
;
4141 INIT_WORK(&cfqd
->unplug_work
, cfq_kick_queue
);
4143 cfqd
->cfq_quantum
= cfq_quantum
;
4144 cfqd
->cfq_fifo_expire
[0] = cfq_fifo_expire
[0];
4145 cfqd
->cfq_fifo_expire
[1] = cfq_fifo_expire
[1];
4146 cfqd
->cfq_back_max
= cfq_back_max
;
4147 cfqd
->cfq_back_penalty
= cfq_back_penalty
;
4148 cfqd
->cfq_slice
[0] = cfq_slice_async
;
4149 cfqd
->cfq_slice
[1] = cfq_slice_sync
;
4150 cfqd
->cfq_target_latency
= cfq_target_latency
;
4151 cfqd
->cfq_slice_async_rq
= cfq_slice_async_rq
;
4152 cfqd
->cfq_slice_idle
= cfq_slice_idle
;
4153 cfqd
->cfq_group_idle
= cfq_group_idle
;
4154 cfqd
->cfq_latency
= 1;
4157 * we optimistically start assuming sync ops weren't delayed in last
4158 * second, in order to have larger depth for async operations.
4160 cfqd
->last_delayed_sync
= jiffies
- HZ
;
4169 * sysfs parts below -->
4172 cfq_var_show(unsigned int var
, char *page
)
4174 return sprintf(page
, "%d\n", var
);
4178 cfq_var_store(unsigned int *var
, const char *page
, size_t count
)
4180 char *p
= (char *) page
;
4182 *var
= simple_strtoul(p
, &p
, 10);
4186 #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \
4187 static ssize_t __FUNC(struct elevator_queue *e, char *page) \
4189 struct cfq_data *cfqd = e->elevator_data; \
4190 unsigned int __data = __VAR; \
4192 __data = jiffies_to_msecs(__data); \
4193 return cfq_var_show(__data, (page)); \
4195 SHOW_FUNCTION(cfq_quantum_show
, cfqd
->cfq_quantum
, 0);
4196 SHOW_FUNCTION(cfq_fifo_expire_sync_show
, cfqd
->cfq_fifo_expire
[1], 1);
4197 SHOW_FUNCTION(cfq_fifo_expire_async_show
, cfqd
->cfq_fifo_expire
[0], 1);
4198 SHOW_FUNCTION(cfq_back_seek_max_show
, cfqd
->cfq_back_max
, 0);
4199 SHOW_FUNCTION(cfq_back_seek_penalty_show
, cfqd
->cfq_back_penalty
, 0);
4200 SHOW_FUNCTION(cfq_slice_idle_show
, cfqd
->cfq_slice_idle
, 1);
4201 SHOW_FUNCTION(cfq_group_idle_show
, cfqd
->cfq_group_idle
, 1);
4202 SHOW_FUNCTION(cfq_slice_sync_show
, cfqd
->cfq_slice
[1], 1);
4203 SHOW_FUNCTION(cfq_slice_async_show
, cfqd
->cfq_slice
[0], 1);
4204 SHOW_FUNCTION(cfq_slice_async_rq_show
, cfqd
->cfq_slice_async_rq
, 0);
4205 SHOW_FUNCTION(cfq_low_latency_show
, cfqd
->cfq_latency
, 0);
4206 SHOW_FUNCTION(cfq_target_latency_show
, cfqd
->cfq_target_latency
, 1);
4207 #undef SHOW_FUNCTION
4209 #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \
4210 static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \
4212 struct cfq_data *cfqd = e->elevator_data; \
4213 unsigned int __data; \
4214 int ret = cfq_var_store(&__data, (page), count); \
4215 if (__data < (MIN)) \
4217 else if (__data > (MAX)) \
4220 *(__PTR) = msecs_to_jiffies(__data); \
4222 *(__PTR) = __data; \
4225 STORE_FUNCTION(cfq_quantum_store
, &cfqd
->cfq_quantum
, 1, UINT_MAX
, 0);
4226 STORE_FUNCTION(cfq_fifo_expire_sync_store
, &cfqd
->cfq_fifo_expire
[1], 1,
4228 STORE_FUNCTION(cfq_fifo_expire_async_store
, &cfqd
->cfq_fifo_expire
[0], 1,
4230 STORE_FUNCTION(cfq_back_seek_max_store
, &cfqd
->cfq_back_max
, 0, UINT_MAX
, 0);
4231 STORE_FUNCTION(cfq_back_seek_penalty_store
, &cfqd
->cfq_back_penalty
, 1,
4233 STORE_FUNCTION(cfq_slice_idle_store
, &cfqd
->cfq_slice_idle
, 0, UINT_MAX
, 1);
4234 STORE_FUNCTION(cfq_group_idle_store
, &cfqd
->cfq_group_idle
, 0, UINT_MAX
, 1);
4235 STORE_FUNCTION(cfq_slice_sync_store
, &cfqd
->cfq_slice
[1], 1, UINT_MAX
, 1);
4236 STORE_FUNCTION(cfq_slice_async_store
, &cfqd
->cfq_slice
[0], 1, UINT_MAX
, 1);
4237 STORE_FUNCTION(cfq_slice_async_rq_store
, &cfqd
->cfq_slice_async_rq
, 1,
4239 STORE_FUNCTION(cfq_low_latency_store
, &cfqd
->cfq_latency
, 0, 1, 0);
4240 STORE_FUNCTION(cfq_target_latency_store
, &cfqd
->cfq_target_latency
, 1, UINT_MAX
, 1);
4241 #undef STORE_FUNCTION
4243 #define CFQ_ATTR(name) \
4244 __ATTR(name, S_IRUGO|S_IWUSR, cfq_##name##_show, cfq_##name##_store)
4246 static struct elv_fs_entry cfq_attrs
[] = {
4248 CFQ_ATTR(fifo_expire_sync
),
4249 CFQ_ATTR(fifo_expire_async
),
4250 CFQ_ATTR(back_seek_max
),
4251 CFQ_ATTR(back_seek_penalty
),
4252 CFQ_ATTR(slice_sync
),
4253 CFQ_ATTR(slice_async
),
4254 CFQ_ATTR(slice_async_rq
),
4255 CFQ_ATTR(slice_idle
),
4256 CFQ_ATTR(group_idle
),
4257 CFQ_ATTR(low_latency
),
4258 CFQ_ATTR(target_latency
),
4262 static struct elevator_type iosched_cfq
= {
4264 .elevator_merge_fn
= cfq_merge
,
4265 .elevator_merged_fn
= cfq_merged_request
,
4266 .elevator_merge_req_fn
= cfq_merged_requests
,
4267 .elevator_allow_merge_fn
= cfq_allow_merge
,
4268 .elevator_bio_merged_fn
= cfq_bio_merged
,
4269 .elevator_dispatch_fn
= cfq_dispatch_requests
,
4270 .elevator_add_req_fn
= cfq_insert_request
,
4271 .elevator_activate_req_fn
= cfq_activate_request
,
4272 .elevator_deactivate_req_fn
= cfq_deactivate_request
,
4273 .elevator_completed_req_fn
= cfq_completed_request
,
4274 .elevator_former_req_fn
= elv_rb_former_request
,
4275 .elevator_latter_req_fn
= elv_rb_latter_request
,
4276 .elevator_init_icq_fn
= cfq_init_icq
,
4277 .elevator_exit_icq_fn
= cfq_exit_icq
,
4278 .elevator_set_req_fn
= cfq_set_request
,
4279 .elevator_put_req_fn
= cfq_put_request
,
4280 .elevator_may_queue_fn
= cfq_may_queue
,
4281 .elevator_init_fn
= cfq_init_queue
,
4282 .elevator_exit_fn
= cfq_exit_queue
,
4284 .icq_size
= sizeof(struct cfq_io_cq
),
4285 .icq_align
= __alignof__(struct cfq_io_cq
),
4286 .elevator_attrs
= cfq_attrs
,
4287 .elevator_name
= "cfq",
4288 .elevator_owner
= THIS_MODULE
,
4291 #ifdef CONFIG_CFQ_GROUP_IOSCHED
4292 static struct blkcg_policy blkcg_policy_cfq
= {
4293 .pd_size
= sizeof(struct cfq_group
),
4294 .cftypes
= cfq_blkcg_files
,
4296 .pd_init_fn
= cfq_pd_init
,
4297 .pd_reset_stats_fn
= cfq_pd_reset_stats
,
4301 static int __init
cfq_init(void)
4306 * could be 0 on HZ < 1000 setups
4308 if (!cfq_slice_async
)
4309 cfq_slice_async
= 1;
4310 if (!cfq_slice_idle
)
4313 #ifdef CONFIG_CFQ_GROUP_IOSCHED
4314 if (!cfq_group_idle
)
4317 ret
= blkcg_policy_register(&blkcg_policy_cfq
);
4325 cfq_pool
= KMEM_CACHE(cfq_queue
, 0);
4329 ret
= elv_register(&iosched_cfq
);
4336 kmem_cache_destroy(cfq_pool
);
4338 #ifdef CONFIG_CFQ_GROUP_IOSCHED
4339 blkcg_policy_unregister(&blkcg_policy_cfq
);
4344 static void __exit
cfq_exit(void)
4346 #ifdef CONFIG_CFQ_GROUP_IOSCHED
4347 blkcg_policy_unregister(&blkcg_policy_cfq
);
4349 elv_unregister(&iosched_cfq
);
4350 kmem_cache_destroy(cfq_pool
);
4353 module_init(cfq_init
);
4354 module_exit(cfq_exit
);
4356 MODULE_AUTHOR("Jens Axboe");
4357 MODULE_LICENSE("GPL");
4358 MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler");