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.
89 struct cfq_ttime ttime
;
91 #define CFQ_RB_ROOT (struct cfq_rb_root) { .rb = RB_ROOT, \
92 .ttime = {.last_end_request = jiffies,},}
95 * Per process-grouping structure
100 /* various state flags, see below */
102 /* parent cfq_data */
103 struct cfq_data
*cfqd
;
104 /* service_tree member */
105 struct rb_node rb_node
;
106 /* service_tree key */
107 unsigned long rb_key
;
108 /* prio tree member */
109 struct rb_node p_node
;
110 /* prio tree root we belong to, if any */
111 struct rb_root
*p_root
;
112 /* sorted list of pending requests */
113 struct rb_root sort_list
;
114 /* if fifo isn't expired, next request to serve */
115 struct request
*next_rq
;
116 /* requests queued in sort_list */
118 /* currently allocated requests */
120 /* fifo list of requests in sort_list */
121 struct list_head fifo
;
123 /* time when queue got scheduled in to dispatch first request. */
124 unsigned long dispatch_start
;
125 unsigned int allocated_slice
;
126 unsigned int slice_dispatch
;
127 /* time when first request from queue completed and slice started. */
128 unsigned long slice_start
;
129 unsigned long slice_end
;
132 /* pending priority requests */
134 /* number of requests that are on the dispatch list or inside driver */
137 /* io prio of this group */
138 unsigned short ioprio
, org_ioprio
;
139 unsigned short ioprio_class
;
144 sector_t last_request_pos
;
146 struct cfq_rb_root
*service_tree
;
147 struct cfq_queue
*new_cfqq
;
148 struct cfq_group
*cfqg
;
149 /* Number of sectors dispatched from queue in single dispatch round */
150 unsigned long nr_sectors
;
154 * First index in the service_trees.
155 * IDLE is handled separately, so it has negative index
165 * Second index in the service_trees.
169 SYNC_NOIDLE_WORKLOAD
= 1,
174 #ifdef CONFIG_CFQ_GROUP_IOSCHED
175 /* total bytes transferred */
176 struct blkg_rwstat service_bytes
;
177 /* total IOs serviced, post merge */
178 struct blkg_rwstat serviced
;
179 /* number of ios merged */
180 struct blkg_rwstat merged
;
181 /* total time spent on device in ns, may not be accurate w/ queueing */
182 struct blkg_rwstat service_time
;
183 /* total time spent waiting in scheduler queue in ns */
184 struct blkg_rwstat wait_time
;
185 /* number of IOs queued up */
186 struct blkg_rwstat queued
;
187 /* total sectors transferred */
188 struct blkg_stat sectors
;
189 /* total disk time and nr sectors dispatched by this group */
190 struct blkg_stat time
;
191 #ifdef CONFIG_DEBUG_BLK_CGROUP
192 /* time not charged to this cgroup */
193 struct blkg_stat unaccounted_time
;
194 /* sum of number of ios queued across all samples */
195 struct blkg_stat avg_queue_size_sum
;
196 /* count of samples taken for average */
197 struct blkg_stat avg_queue_size_samples
;
198 /* how many times this group has been removed from service tree */
199 struct blkg_stat dequeue
;
200 /* total time spent waiting for it to be assigned a timeslice. */
201 struct blkg_stat group_wait_time
;
202 /* time spent idling for this blkcg_gq */
203 struct blkg_stat idle_time
;
204 /* total time with empty current active q with other requests queued */
205 struct blkg_stat empty_time
;
206 /* fields after this shouldn't be cleared on stat reset */
207 uint64_t start_group_wait_time
;
208 uint64_t start_idle_time
;
209 uint64_t start_empty_time
;
211 #endif /* CONFIG_DEBUG_BLK_CGROUP */
212 #endif /* CONFIG_CFQ_GROUP_IOSCHED */
215 /* This is per cgroup per device grouping structure */
217 /* must be the first member */
218 struct blkg_policy_data pd
;
220 /* group service_tree member */
221 struct rb_node rb_node
;
223 /* group service_tree key */
227 * The number of active cfqgs and sum of their weights under this
228 * cfqg. This covers this cfqg's leaf_weight and all children's
229 * weights, but does not cover weights of further descendants.
231 * If a cfqg is on the service tree, it's active. An active cfqg
232 * also activates its parent and contributes to the children_weight
236 unsigned int children_weight
;
239 * vfraction is the fraction of vdisktime that the tasks in this
240 * cfqg are entitled to. This is determined by compounding the
241 * ratios walking up from this cfqg to the root.
243 * It is in fixed point w/ CFQ_SERVICE_SHIFT and the sum of all
244 * vfractions on a service tree is approximately 1. The sum may
245 * deviate a bit due to rounding errors and fluctuations caused by
246 * cfqgs entering and leaving the service tree.
248 unsigned int vfraction
;
251 * There are two weights - (internal) weight is the weight of this
252 * cfqg against the sibling cfqgs. leaf_weight is the wight of
253 * this cfqg against the child cfqgs. For the root cfqg, both
254 * weights are kept in sync for backward compatibility.
257 unsigned int new_weight
;
258 unsigned int dev_weight
;
260 unsigned int leaf_weight
;
261 unsigned int new_leaf_weight
;
262 unsigned int dev_leaf_weight
;
264 /* number of cfqq currently on this group */
268 * Per group busy queues average. Useful for workload slice calc. We
269 * create the array for each prio class but at run time it is used
270 * only for RT and BE class and slot for IDLE class remains unused.
271 * This is primarily done to avoid confusion and a gcc warning.
273 unsigned int busy_queues_avg
[CFQ_PRIO_NR
];
275 * rr lists of queues with requests. We maintain service trees for
276 * RT and BE classes. These trees are subdivided in subclasses
277 * of SYNC, SYNC_NOIDLE and ASYNC based on workload type. For IDLE
278 * class there is no subclassification and all the cfq queues go on
279 * a single tree service_tree_idle.
280 * Counts are embedded in the cfq_rb_root
282 struct cfq_rb_root service_trees
[2][3];
283 struct cfq_rb_root service_tree_idle
;
285 unsigned long saved_wl_slice
;
286 enum wl_type_t saved_wl_type
;
287 enum wl_class_t saved_wl_class
;
289 /* number of requests that are on the dispatch list or inside driver */
291 struct cfq_ttime ttime
;
292 struct cfqg_stats stats
;
296 struct io_cq icq
; /* must be the first member */
297 struct cfq_queue
*cfqq
[2];
298 struct cfq_ttime ttime
;
299 int ioprio
; /* the current ioprio */
300 #ifdef CONFIG_CFQ_GROUP_IOSCHED
301 uint64_t blkcg_id
; /* the current blkcg ID */
306 * Per block device queue structure
309 struct request_queue
*queue
;
310 /* Root service tree for cfq_groups */
311 struct cfq_rb_root grp_service_tree
;
312 struct cfq_group
*root_group
;
315 * The priority currently being served
317 enum wl_class_t serving_wl_class
;
318 enum wl_type_t serving_wl_type
;
319 unsigned long workload_expires
;
320 struct cfq_group
*serving_group
;
323 * Each priority tree is sorted by next_request position. These
324 * trees are used when determining if two or more queues are
325 * interleaving requests (see cfq_close_cooperator).
327 struct rb_root prio_trees
[CFQ_PRIO_LISTS
];
329 unsigned int busy_queues
;
330 unsigned int busy_sync_queues
;
336 * queue-depth detection
342 * -1 => indeterminate, (cfq will behave as if NCQ is present, to allow better detection)
343 * 1 => NCQ is present (hw_tag_est_depth is the estimated max depth)
346 int hw_tag_est_depth
;
347 unsigned int hw_tag_samples
;
350 * idle window management
352 struct timer_list idle_slice_timer
;
353 struct work_struct unplug_work
;
355 struct cfq_queue
*active_queue
;
356 struct cfq_io_cq
*active_cic
;
359 * async queue for each priority case
361 struct cfq_queue
*async_cfqq
[2][IOPRIO_BE_NR
];
362 struct cfq_queue
*async_idle_cfqq
;
364 sector_t last_position
;
367 * tunables, see top of file
369 unsigned int cfq_quantum
;
370 unsigned int cfq_fifo_expire
[2];
371 unsigned int cfq_back_penalty
;
372 unsigned int cfq_back_max
;
373 unsigned int cfq_slice
[2];
374 unsigned int cfq_slice_async_rq
;
375 unsigned int cfq_slice_idle
;
376 unsigned int cfq_group_idle
;
377 unsigned int cfq_latency
;
378 unsigned int cfq_target_latency
;
381 * Fallback dummy cfqq for extreme OOM conditions
383 struct cfq_queue oom_cfqq
;
385 unsigned long last_delayed_sync
;
388 static struct cfq_group
*cfq_get_next_cfqg(struct cfq_data
*cfqd
);
390 static struct cfq_rb_root
*st_for(struct cfq_group
*cfqg
,
391 enum wl_class_t
class,
397 if (class == IDLE_WORKLOAD
)
398 return &cfqg
->service_tree_idle
;
400 return &cfqg
->service_trees
[class][type
];
403 enum cfqq_state_flags
{
404 CFQ_CFQQ_FLAG_on_rr
= 0, /* on round-robin busy list */
405 CFQ_CFQQ_FLAG_wait_request
, /* waiting for a request */
406 CFQ_CFQQ_FLAG_must_dispatch
, /* must be allowed a dispatch */
407 CFQ_CFQQ_FLAG_must_alloc_slice
, /* per-slice must_alloc flag */
408 CFQ_CFQQ_FLAG_fifo_expire
, /* FIFO checked in this slice */
409 CFQ_CFQQ_FLAG_idle_window
, /* slice idling enabled */
410 CFQ_CFQQ_FLAG_prio_changed
, /* task priority has changed */
411 CFQ_CFQQ_FLAG_slice_new
, /* no requests dispatched in slice */
412 CFQ_CFQQ_FLAG_sync
, /* synchronous queue */
413 CFQ_CFQQ_FLAG_coop
, /* cfqq is shared */
414 CFQ_CFQQ_FLAG_split_coop
, /* shared cfqq will be splitted */
415 CFQ_CFQQ_FLAG_deep
, /* sync cfqq experienced large depth */
416 CFQ_CFQQ_FLAG_wait_busy
, /* Waiting for next request */
419 #define CFQ_CFQQ_FNS(name) \
420 static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \
422 (cfqq)->flags |= (1 << CFQ_CFQQ_FLAG_##name); \
424 static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \
426 (cfqq)->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \
428 static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \
430 return ((cfqq)->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \
434 CFQ_CFQQ_FNS(wait_request
);
435 CFQ_CFQQ_FNS(must_dispatch
);
436 CFQ_CFQQ_FNS(must_alloc_slice
);
437 CFQ_CFQQ_FNS(fifo_expire
);
438 CFQ_CFQQ_FNS(idle_window
);
439 CFQ_CFQQ_FNS(prio_changed
);
440 CFQ_CFQQ_FNS(slice_new
);
443 CFQ_CFQQ_FNS(split_coop
);
445 CFQ_CFQQ_FNS(wait_busy
);
448 static inline struct cfq_group
*pd_to_cfqg(struct blkg_policy_data
*pd
)
450 return pd
? container_of(pd
, struct cfq_group
, pd
) : NULL
;
453 static inline struct blkcg_gq
*cfqg_to_blkg(struct cfq_group
*cfqg
)
455 return pd_to_blkg(&cfqg
->pd
);
458 #if defined(CONFIG_CFQ_GROUP_IOSCHED) && defined(CONFIG_DEBUG_BLK_CGROUP)
460 /* cfqg stats flags */
461 enum cfqg_stats_flags
{
462 CFQG_stats_waiting
= 0,
467 #define CFQG_FLAG_FNS(name) \
468 static inline void cfqg_stats_mark_##name(struct cfqg_stats *stats) \
470 stats->flags |= (1 << CFQG_stats_##name); \
472 static inline void cfqg_stats_clear_##name(struct cfqg_stats *stats) \
474 stats->flags &= ~(1 << CFQG_stats_##name); \
476 static inline int cfqg_stats_##name(struct cfqg_stats *stats) \
478 return (stats->flags & (1 << CFQG_stats_##name)) != 0; \
481 CFQG_FLAG_FNS(waiting)
482 CFQG_FLAG_FNS(idling
)
486 /* This should be called with the queue_lock held. */
487 static void cfqg_stats_update_group_wait_time(struct cfqg_stats
*stats
)
489 unsigned long long now
;
491 if (!cfqg_stats_waiting(stats
))
495 if (time_after64(now
, stats
->start_group_wait_time
))
496 blkg_stat_add(&stats
->group_wait_time
,
497 now
- stats
->start_group_wait_time
);
498 cfqg_stats_clear_waiting(stats
);
501 /* This should be called with the queue_lock held. */
502 static void cfqg_stats_set_start_group_wait_time(struct cfq_group
*cfqg
,
503 struct cfq_group
*curr_cfqg
)
505 struct cfqg_stats
*stats
= &cfqg
->stats
;
507 if (cfqg_stats_waiting(stats
))
509 if (cfqg
== curr_cfqg
)
511 stats
->start_group_wait_time
= sched_clock();
512 cfqg_stats_mark_waiting(stats
);
515 /* This should be called with the queue_lock held. */
516 static void cfqg_stats_end_empty_time(struct cfqg_stats
*stats
)
518 unsigned long long now
;
520 if (!cfqg_stats_empty(stats
))
524 if (time_after64(now
, stats
->start_empty_time
))
525 blkg_stat_add(&stats
->empty_time
,
526 now
- stats
->start_empty_time
);
527 cfqg_stats_clear_empty(stats
);
530 static void cfqg_stats_update_dequeue(struct cfq_group
*cfqg
)
532 blkg_stat_add(&cfqg
->stats
.dequeue
, 1);
535 static void cfqg_stats_set_start_empty_time(struct cfq_group
*cfqg
)
537 struct cfqg_stats
*stats
= &cfqg
->stats
;
539 if (blkg_rwstat_sum(&stats
->queued
))
543 * group is already marked empty. This can happen if cfqq got new
544 * request in parent group and moved to this group while being added
545 * to service tree. Just ignore the event and move on.
547 if (cfqg_stats_empty(stats
))
550 stats
->start_empty_time
= sched_clock();
551 cfqg_stats_mark_empty(stats
);
554 static void cfqg_stats_update_idle_time(struct cfq_group
*cfqg
)
556 struct cfqg_stats
*stats
= &cfqg
->stats
;
558 if (cfqg_stats_idling(stats
)) {
559 unsigned long long now
= sched_clock();
561 if (time_after64(now
, stats
->start_idle_time
))
562 blkg_stat_add(&stats
->idle_time
,
563 now
- stats
->start_idle_time
);
564 cfqg_stats_clear_idling(stats
);
568 static void cfqg_stats_set_start_idle_time(struct cfq_group
*cfqg
)
570 struct cfqg_stats
*stats
= &cfqg
->stats
;
572 BUG_ON(cfqg_stats_idling(stats
));
574 stats
->start_idle_time
= sched_clock();
575 cfqg_stats_mark_idling(stats
);
578 static void cfqg_stats_update_avg_queue_size(struct cfq_group
*cfqg
)
580 struct cfqg_stats
*stats
= &cfqg
->stats
;
582 blkg_stat_add(&stats
->avg_queue_size_sum
,
583 blkg_rwstat_sum(&stats
->queued
));
584 blkg_stat_add(&stats
->avg_queue_size_samples
, 1);
585 cfqg_stats_update_group_wait_time(stats
);
588 #else /* CONFIG_CFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */
590 static inline void cfqg_stats_set_start_group_wait_time(struct cfq_group
*cfqg
, struct cfq_group
*curr_cfqg
) { }
591 static inline void cfqg_stats_end_empty_time(struct cfqg_stats
*stats
) { }
592 static inline void cfqg_stats_update_dequeue(struct cfq_group
*cfqg
) { }
593 static inline void cfqg_stats_set_start_empty_time(struct cfq_group
*cfqg
) { }
594 static inline void cfqg_stats_update_idle_time(struct cfq_group
*cfqg
) { }
595 static inline void cfqg_stats_set_start_idle_time(struct cfq_group
*cfqg
) { }
596 static inline void cfqg_stats_update_avg_queue_size(struct cfq_group
*cfqg
) { }
598 #endif /* CONFIG_CFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */
600 #ifdef CONFIG_CFQ_GROUP_IOSCHED
602 static struct blkcg_policy blkcg_policy_cfq
;
604 static inline struct cfq_group
*blkg_to_cfqg(struct blkcg_gq
*blkg
)
606 return pd_to_cfqg(blkg_to_pd(blkg
, &blkcg_policy_cfq
));
610 * Determine the parent cfqg for weight calculation. Currently, cfqg
611 * scheduling is flat and the root is the parent of everyone else.
613 static inline struct cfq_group
*cfqg_flat_parent(struct cfq_group
*cfqg
)
615 struct blkcg_gq
*blkg
= cfqg_to_blkg(cfqg
);
616 struct cfq_group
*root
;
620 root
= blkg_to_cfqg(blkg
);
622 return root
!= cfqg
? root
: NULL
;
625 static inline void cfqg_get(struct cfq_group
*cfqg
)
627 return blkg_get(cfqg_to_blkg(cfqg
));
630 static inline void cfqg_put(struct cfq_group
*cfqg
)
632 return blkg_put(cfqg_to_blkg(cfqg
));
635 #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) do { \
638 blkg_path(cfqg_to_blkg((cfqq)->cfqg), __pbuf, sizeof(__pbuf)); \
639 blk_add_trace_msg((cfqd)->queue, "cfq%d%c%c %s " fmt, (cfqq)->pid, \
640 cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \
641 cfqq_type((cfqq)) == SYNC_NOIDLE_WORKLOAD ? 'N' : ' ',\
645 #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) do { \
648 blkg_path(cfqg_to_blkg(cfqg), __pbuf, sizeof(__pbuf)); \
649 blk_add_trace_msg((cfqd)->queue, "%s " fmt, __pbuf, ##args); \
652 static inline void cfqg_stats_update_io_add(struct cfq_group
*cfqg
,
653 struct cfq_group
*curr_cfqg
, int rw
)
655 blkg_rwstat_add(&cfqg
->stats
.queued
, rw
, 1);
656 cfqg_stats_end_empty_time(&cfqg
->stats
);
657 cfqg_stats_set_start_group_wait_time(cfqg
, curr_cfqg
);
660 static inline void cfqg_stats_update_timeslice_used(struct cfq_group
*cfqg
,
661 unsigned long time
, unsigned long unaccounted_time
)
663 blkg_stat_add(&cfqg
->stats
.time
, time
);
664 #ifdef CONFIG_DEBUG_BLK_CGROUP
665 blkg_stat_add(&cfqg
->stats
.unaccounted_time
, unaccounted_time
);
669 static inline void cfqg_stats_update_io_remove(struct cfq_group
*cfqg
, int rw
)
671 blkg_rwstat_add(&cfqg
->stats
.queued
, rw
, -1);
674 static inline void cfqg_stats_update_io_merged(struct cfq_group
*cfqg
, int rw
)
676 blkg_rwstat_add(&cfqg
->stats
.merged
, rw
, 1);
679 static inline void cfqg_stats_update_dispatch(struct cfq_group
*cfqg
,
680 uint64_t bytes
, int rw
)
682 blkg_stat_add(&cfqg
->stats
.sectors
, bytes
>> 9);
683 blkg_rwstat_add(&cfqg
->stats
.serviced
, rw
, 1);
684 blkg_rwstat_add(&cfqg
->stats
.service_bytes
, rw
, bytes
);
687 static inline void cfqg_stats_update_completion(struct cfq_group
*cfqg
,
688 uint64_t start_time
, uint64_t io_start_time
, int rw
)
690 struct cfqg_stats
*stats
= &cfqg
->stats
;
691 unsigned long long now
= sched_clock();
693 if (time_after64(now
, io_start_time
))
694 blkg_rwstat_add(&stats
->service_time
, rw
, now
- io_start_time
);
695 if (time_after64(io_start_time
, start_time
))
696 blkg_rwstat_add(&stats
->wait_time
, rw
,
697 io_start_time
- start_time
);
700 static void cfq_pd_reset_stats(struct blkcg_gq
*blkg
)
702 struct cfq_group
*cfqg
= blkg_to_cfqg(blkg
);
703 struct cfqg_stats
*stats
= &cfqg
->stats
;
705 /* queued stats shouldn't be cleared */
706 blkg_rwstat_reset(&stats
->service_bytes
);
707 blkg_rwstat_reset(&stats
->serviced
);
708 blkg_rwstat_reset(&stats
->merged
);
709 blkg_rwstat_reset(&stats
->service_time
);
710 blkg_rwstat_reset(&stats
->wait_time
);
711 blkg_stat_reset(&stats
->time
);
712 #ifdef CONFIG_DEBUG_BLK_CGROUP
713 blkg_stat_reset(&stats
->unaccounted_time
);
714 blkg_stat_reset(&stats
->avg_queue_size_sum
);
715 blkg_stat_reset(&stats
->avg_queue_size_samples
);
716 blkg_stat_reset(&stats
->dequeue
);
717 blkg_stat_reset(&stats
->group_wait_time
);
718 blkg_stat_reset(&stats
->idle_time
);
719 blkg_stat_reset(&stats
->empty_time
);
723 #else /* CONFIG_CFQ_GROUP_IOSCHED */
725 static inline struct cfq_group
*cfqg_flat_parent(struct cfq_group
*cfqg
) { return NULL
; }
726 static inline void cfqg_get(struct cfq_group
*cfqg
) { }
727 static inline void cfqg_put(struct cfq_group
*cfqg
) { }
729 #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \
730 blk_add_trace_msg((cfqd)->queue, "cfq%d%c%c " fmt, (cfqq)->pid, \
731 cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \
732 cfqq_type((cfqq)) == SYNC_NOIDLE_WORKLOAD ? 'N' : ' ',\
734 #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) do {} while (0)
736 static inline void cfqg_stats_update_io_add(struct cfq_group
*cfqg
,
737 struct cfq_group
*curr_cfqg
, int rw
) { }
738 static inline void cfqg_stats_update_timeslice_used(struct cfq_group
*cfqg
,
739 unsigned long time
, unsigned long unaccounted_time
) { }
740 static inline void cfqg_stats_update_io_remove(struct cfq_group
*cfqg
, int rw
) { }
741 static inline void cfqg_stats_update_io_merged(struct cfq_group
*cfqg
, int rw
) { }
742 static inline void cfqg_stats_update_dispatch(struct cfq_group
*cfqg
,
743 uint64_t bytes
, int rw
) { }
744 static inline void cfqg_stats_update_completion(struct cfq_group
*cfqg
,
745 uint64_t start_time
, uint64_t io_start_time
, int rw
) { }
747 #endif /* CONFIG_CFQ_GROUP_IOSCHED */
749 #define cfq_log(cfqd, fmt, args...) \
750 blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args)
752 /* Traverses through cfq group service trees */
753 #define for_each_cfqg_st(cfqg, i, j, st) \
754 for (i = 0; i <= IDLE_WORKLOAD; i++) \
755 for (j = 0, st = i < IDLE_WORKLOAD ? &cfqg->service_trees[i][j]\
756 : &cfqg->service_tree_idle; \
757 (i < IDLE_WORKLOAD && j <= SYNC_WORKLOAD) || \
758 (i == IDLE_WORKLOAD && j == 0); \
759 j++, st = i < IDLE_WORKLOAD ? \
760 &cfqg->service_trees[i][j]: NULL) \
762 static inline bool cfq_io_thinktime_big(struct cfq_data *cfqd,
763 struct cfq_ttime
*ttime
, bool group_idle
)
766 if (!sample_valid(ttime
->ttime_samples
))
769 slice
= cfqd
->cfq_group_idle
;
771 slice
= cfqd
->cfq_slice_idle
;
772 return ttime
->ttime_mean
> slice
;
775 static inline bool iops_mode(struct cfq_data
*cfqd
)
778 * If we are not idling on queues and it is a NCQ drive, parallel
779 * execution of requests is on and measuring time is not possible
780 * in most of the cases until and unless we drive shallower queue
781 * depths and that becomes a performance bottleneck. In such cases
782 * switch to start providing fairness in terms of number of IOs.
784 if (!cfqd
->cfq_slice_idle
&& cfqd
->hw_tag
)
790 static inline enum wl_class_t
cfqq_class(struct cfq_queue
*cfqq
)
792 if (cfq_class_idle(cfqq
))
793 return IDLE_WORKLOAD
;
794 if (cfq_class_rt(cfqq
))
800 static enum wl_type_t
cfqq_type(struct cfq_queue
*cfqq
)
802 if (!cfq_cfqq_sync(cfqq
))
803 return ASYNC_WORKLOAD
;
804 if (!cfq_cfqq_idle_window(cfqq
))
805 return SYNC_NOIDLE_WORKLOAD
;
806 return SYNC_WORKLOAD
;
809 static inline int cfq_group_busy_queues_wl(enum wl_class_t wl_class
,
810 struct cfq_data
*cfqd
,
811 struct cfq_group
*cfqg
)
813 if (wl_class
== IDLE_WORKLOAD
)
814 return cfqg
->service_tree_idle
.count
;
816 return cfqg
->service_trees
[wl_class
][ASYNC_WORKLOAD
].count
+
817 cfqg
->service_trees
[wl_class
][SYNC_NOIDLE_WORKLOAD
].count
+
818 cfqg
->service_trees
[wl_class
][SYNC_WORKLOAD
].count
;
821 static inline int cfqg_busy_async_queues(struct cfq_data
*cfqd
,
822 struct cfq_group
*cfqg
)
824 return cfqg
->service_trees
[RT_WORKLOAD
][ASYNC_WORKLOAD
].count
+
825 cfqg
->service_trees
[BE_WORKLOAD
][ASYNC_WORKLOAD
].count
;
828 static void cfq_dispatch_insert(struct request_queue
*, struct request
*);
829 static struct cfq_queue
*cfq_get_queue(struct cfq_data
*cfqd
, bool is_sync
,
830 struct cfq_io_cq
*cic
, struct bio
*bio
,
833 static inline struct cfq_io_cq
*icq_to_cic(struct io_cq
*icq
)
835 /* cic->icq is the first member, %NULL will convert to %NULL */
836 return container_of(icq
, struct cfq_io_cq
, icq
);
839 static inline struct cfq_io_cq
*cfq_cic_lookup(struct cfq_data
*cfqd
,
840 struct io_context
*ioc
)
843 return icq_to_cic(ioc_lookup_icq(ioc
, cfqd
->queue
));
847 static inline struct cfq_queue
*cic_to_cfqq(struct cfq_io_cq
*cic
, bool is_sync
)
849 return cic
->cfqq
[is_sync
];
852 static inline void cic_set_cfqq(struct cfq_io_cq
*cic
, struct cfq_queue
*cfqq
,
855 cic
->cfqq
[is_sync
] = cfqq
;
858 static inline struct cfq_data
*cic_to_cfqd(struct cfq_io_cq
*cic
)
860 return cic
->icq
.q
->elevator
->elevator_data
;
864 * We regard a request as SYNC, if it's either a read or has the SYNC bit
865 * set (in which case it could also be direct WRITE).
867 static inline bool cfq_bio_sync(struct bio
*bio
)
869 return bio_data_dir(bio
) == READ
|| (bio
->bi_rw
& REQ_SYNC
);
873 * scheduler run of queue, if there are requests pending and no one in the
874 * driver that will restart queueing
876 static inline void cfq_schedule_dispatch(struct cfq_data
*cfqd
)
878 if (cfqd
->busy_queues
) {
879 cfq_log(cfqd
, "schedule dispatch");
880 kblockd_schedule_work(cfqd
->queue
, &cfqd
->unplug_work
);
885 * Scale schedule slice based on io priority. Use the sync time slice only
886 * if a queue is marked sync and has sync io queued. A sync queue with async
887 * io only, should not get full sync slice length.
889 static inline int cfq_prio_slice(struct cfq_data
*cfqd
, bool sync
,
892 const int base_slice
= cfqd
->cfq_slice
[sync
];
894 WARN_ON(prio
>= IOPRIO_BE_NR
);
896 return base_slice
+ (base_slice
/CFQ_SLICE_SCALE
* (4 - prio
));
900 cfq_prio_to_slice(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
902 return cfq_prio_slice(cfqd
, cfq_cfqq_sync(cfqq
), cfqq
->ioprio
);
906 * cfqg_scale_charge - scale disk time charge according to cfqg weight
907 * @charge: disk time being charged
908 * @vfraction: vfraction of the cfqg, fixed point w/ CFQ_SERVICE_SHIFT
910 * Scale @charge according to @vfraction, which is in range (0, 1]. The
911 * scaling is inversely proportional.
913 * scaled = charge / vfraction
915 * The result is also in fixed point w/ CFQ_SERVICE_SHIFT.
917 static inline u64
cfqg_scale_charge(unsigned long charge
,
918 unsigned int vfraction
)
920 u64 c
= charge
<< CFQ_SERVICE_SHIFT
; /* make it fixed point */
922 /* charge / vfraction */
923 c
<<= CFQ_SERVICE_SHIFT
;
924 do_div(c
, vfraction
);
928 static inline u64
max_vdisktime(u64 min_vdisktime
, u64 vdisktime
)
930 s64 delta
= (s64
)(vdisktime
- min_vdisktime
);
932 min_vdisktime
= vdisktime
;
934 return min_vdisktime
;
937 static inline u64
min_vdisktime(u64 min_vdisktime
, u64 vdisktime
)
939 s64 delta
= (s64
)(vdisktime
- min_vdisktime
);
941 min_vdisktime
= vdisktime
;
943 return min_vdisktime
;
946 static void update_min_vdisktime(struct cfq_rb_root
*st
)
948 struct cfq_group
*cfqg
;
951 cfqg
= rb_entry_cfqg(st
->left
);
952 st
->min_vdisktime
= max_vdisktime(st
->min_vdisktime
,
958 * get averaged number of queues of RT/BE priority.
959 * average is updated, with a formula that gives more weight to higher numbers,
960 * to quickly follows sudden increases and decrease slowly
963 static inline unsigned cfq_group_get_avg_queues(struct cfq_data
*cfqd
,
964 struct cfq_group
*cfqg
, bool rt
)
966 unsigned min_q
, max_q
;
967 unsigned mult
= cfq_hist_divisor
- 1;
968 unsigned round
= cfq_hist_divisor
/ 2;
969 unsigned busy
= cfq_group_busy_queues_wl(rt
, cfqd
, cfqg
);
971 min_q
= min(cfqg
->busy_queues_avg
[rt
], busy
);
972 max_q
= max(cfqg
->busy_queues_avg
[rt
], busy
);
973 cfqg
->busy_queues_avg
[rt
] = (mult
* max_q
+ min_q
+ round
) /
975 return cfqg
->busy_queues_avg
[rt
];
978 static inline unsigned
979 cfq_group_slice(struct cfq_data
*cfqd
, struct cfq_group
*cfqg
)
981 return cfqd
->cfq_target_latency
* cfqg
->vfraction
>> CFQ_SERVICE_SHIFT
;
984 static inline unsigned
985 cfq_scaled_cfqq_slice(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
987 unsigned slice
= cfq_prio_to_slice(cfqd
, cfqq
);
988 if (cfqd
->cfq_latency
) {
990 * interested queues (we consider only the ones with the same
991 * priority class in the cfq group)
993 unsigned iq
= cfq_group_get_avg_queues(cfqd
, cfqq
->cfqg
,
995 unsigned sync_slice
= cfqd
->cfq_slice
[1];
996 unsigned expect_latency
= sync_slice
* iq
;
997 unsigned group_slice
= cfq_group_slice(cfqd
, cfqq
->cfqg
);
999 if (expect_latency
> group_slice
) {
1000 unsigned base_low_slice
= 2 * cfqd
->cfq_slice_idle
;
1001 /* scale low_slice according to IO priority
1002 * and sync vs async */
1003 unsigned low_slice
=
1004 min(slice
, base_low_slice
* slice
/ sync_slice
);
1005 /* the adapted slice value is scaled to fit all iqs
1006 * into the target latency */
1007 slice
= max(slice
* group_slice
/ expect_latency
,
1015 cfq_set_prio_slice(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
1017 unsigned slice
= cfq_scaled_cfqq_slice(cfqd
, cfqq
);
1019 cfqq
->slice_start
= jiffies
;
1020 cfqq
->slice_end
= jiffies
+ slice
;
1021 cfqq
->allocated_slice
= slice
;
1022 cfq_log_cfqq(cfqd
, cfqq
, "set_slice=%lu", cfqq
->slice_end
- jiffies
);
1026 * We need to wrap this check in cfq_cfqq_slice_new(), since ->slice_end
1027 * isn't valid until the first request from the dispatch is activated
1028 * and the slice time set.
1030 static inline bool cfq_slice_used(struct cfq_queue
*cfqq
)
1032 if (cfq_cfqq_slice_new(cfqq
))
1034 if (time_before(jiffies
, cfqq
->slice_end
))
1041 * Lifted from AS - choose which of rq1 and rq2 that is best served now.
1042 * We choose the request that is closest to the head right now. Distance
1043 * behind the head is penalized and only allowed to a certain extent.
1045 static struct request
*
1046 cfq_choose_req(struct cfq_data
*cfqd
, struct request
*rq1
, struct request
*rq2
, sector_t last
)
1048 sector_t s1
, s2
, d1
= 0, d2
= 0;
1049 unsigned long back_max
;
1050 #define CFQ_RQ1_WRAP 0x01 /* request 1 wraps */
1051 #define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */
1052 unsigned wrap
= 0; /* bit mask: requests behind the disk head? */
1054 if (rq1
== NULL
|| rq1
== rq2
)
1059 if (rq_is_sync(rq1
) != rq_is_sync(rq2
))
1060 return rq_is_sync(rq1
) ? rq1
: rq2
;
1062 if ((rq1
->cmd_flags
^ rq2
->cmd_flags
) & REQ_PRIO
)
1063 return rq1
->cmd_flags
& REQ_PRIO
? rq1
: rq2
;
1065 s1
= blk_rq_pos(rq1
);
1066 s2
= blk_rq_pos(rq2
);
1069 * by definition, 1KiB is 2 sectors
1071 back_max
= cfqd
->cfq_back_max
* 2;
1074 * Strict one way elevator _except_ in the case where we allow
1075 * short backward seeks which are biased as twice the cost of a
1076 * similar forward seek.
1080 else if (s1
+ back_max
>= last
)
1081 d1
= (last
- s1
) * cfqd
->cfq_back_penalty
;
1083 wrap
|= CFQ_RQ1_WRAP
;
1087 else if (s2
+ back_max
>= last
)
1088 d2
= (last
- s2
) * cfqd
->cfq_back_penalty
;
1090 wrap
|= CFQ_RQ2_WRAP
;
1092 /* Found required data */
1095 * By doing switch() on the bit mask "wrap" we avoid having to
1096 * check two variables for all permutations: --> faster!
1099 case 0: /* common case for CFQ: rq1 and rq2 not wrapped */
1115 case (CFQ_RQ1_WRAP
|CFQ_RQ2_WRAP
): /* both rqs wrapped */
1118 * Since both rqs are wrapped,
1119 * start with the one that's further behind head
1120 * (--> only *one* back seek required),
1121 * since back seek takes more time than forward.
1131 * The below is leftmost cache rbtree addon
1133 static struct cfq_queue
*cfq_rb_first(struct cfq_rb_root
*root
)
1135 /* Service tree is empty */
1140 root
->left
= rb_first(&root
->rb
);
1143 return rb_entry(root
->left
, struct cfq_queue
, rb_node
);
1148 static struct cfq_group
*cfq_rb_first_group(struct cfq_rb_root
*root
)
1151 root
->left
= rb_first(&root
->rb
);
1154 return rb_entry_cfqg(root
->left
);
1159 static void rb_erase_init(struct rb_node
*n
, struct rb_root
*root
)
1165 static void cfq_rb_erase(struct rb_node
*n
, struct cfq_rb_root
*root
)
1167 if (root
->left
== n
)
1169 rb_erase_init(n
, &root
->rb
);
1174 * would be nice to take fifo expire time into account as well
1176 static struct request
*
1177 cfq_find_next_rq(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
1178 struct request
*last
)
1180 struct rb_node
*rbnext
= rb_next(&last
->rb_node
);
1181 struct rb_node
*rbprev
= rb_prev(&last
->rb_node
);
1182 struct request
*next
= NULL
, *prev
= NULL
;
1184 BUG_ON(RB_EMPTY_NODE(&last
->rb_node
));
1187 prev
= rb_entry_rq(rbprev
);
1190 next
= rb_entry_rq(rbnext
);
1192 rbnext
= rb_first(&cfqq
->sort_list
);
1193 if (rbnext
&& rbnext
!= &last
->rb_node
)
1194 next
= rb_entry_rq(rbnext
);
1197 return cfq_choose_req(cfqd
, next
, prev
, blk_rq_pos(last
));
1200 static unsigned long cfq_slice_offset(struct cfq_data
*cfqd
,
1201 struct cfq_queue
*cfqq
)
1204 * just an approximation, should be ok.
1206 return (cfqq
->cfqg
->nr_cfqq
- 1) * (cfq_prio_slice(cfqd
, 1, 0) -
1207 cfq_prio_slice(cfqd
, cfq_cfqq_sync(cfqq
), cfqq
->ioprio
));
1211 cfqg_key(struct cfq_rb_root
*st
, struct cfq_group
*cfqg
)
1213 return cfqg
->vdisktime
- st
->min_vdisktime
;
1217 __cfq_group_service_tree_add(struct cfq_rb_root
*st
, struct cfq_group
*cfqg
)
1219 struct rb_node
**node
= &st
->rb
.rb_node
;
1220 struct rb_node
*parent
= NULL
;
1221 struct cfq_group
*__cfqg
;
1222 s64 key
= cfqg_key(st
, cfqg
);
1225 while (*node
!= NULL
) {
1227 __cfqg
= rb_entry_cfqg(parent
);
1229 if (key
< cfqg_key(st
, __cfqg
))
1230 node
= &parent
->rb_left
;
1232 node
= &parent
->rb_right
;
1238 st
->left
= &cfqg
->rb_node
;
1240 rb_link_node(&cfqg
->rb_node
, parent
, node
);
1241 rb_insert_color(&cfqg
->rb_node
, &st
->rb
);
1245 cfq_update_group_weight(struct cfq_group
*cfqg
)
1247 BUG_ON(!RB_EMPTY_NODE(&cfqg
->rb_node
));
1249 if (cfqg
->new_weight
) {
1250 cfqg
->weight
= cfqg
->new_weight
;
1251 cfqg
->new_weight
= 0;
1254 if (cfqg
->new_leaf_weight
) {
1255 cfqg
->leaf_weight
= cfqg
->new_leaf_weight
;
1256 cfqg
->new_leaf_weight
= 0;
1261 cfq_group_service_tree_add(struct cfq_rb_root
*st
, struct cfq_group
*cfqg
)
1263 unsigned int vfr
= 1 << CFQ_SERVICE_SHIFT
; /* start with 1 */
1264 struct cfq_group
*pos
= cfqg
;
1265 struct cfq_group
*parent
;
1268 /* add to the service tree */
1269 BUG_ON(!RB_EMPTY_NODE(&cfqg
->rb_node
));
1271 cfq_update_group_weight(cfqg
);
1272 __cfq_group_service_tree_add(st
, cfqg
);
1275 * Activate @cfqg and calculate the portion of vfraction @cfqg is
1276 * entitled to. vfraction is calculated by walking the tree
1277 * towards the root calculating the fraction it has at each level.
1278 * The compounded ratio is how much vfraction @cfqg owns.
1280 * Start with the proportion tasks in this cfqg has against active
1281 * children cfqgs - its leaf_weight against children_weight.
1283 propagate
= !pos
->nr_active
++;
1284 pos
->children_weight
+= pos
->leaf_weight
;
1285 vfr
= vfr
* pos
->leaf_weight
/ pos
->children_weight
;
1288 * Compound ->weight walking up the tree. Both activation and
1289 * vfraction calculation are done in the same loop. Propagation
1290 * stops once an already activated node is met. vfraction
1291 * calculation should always continue to the root.
1293 while ((parent
= cfqg_flat_parent(pos
))) {
1295 propagate
= !parent
->nr_active
++;
1296 parent
->children_weight
+= pos
->weight
;
1298 vfr
= vfr
* pos
->weight
/ parent
->children_weight
;
1302 cfqg
->vfraction
= max_t(unsigned, vfr
, 1);
1306 cfq_group_notify_queue_add(struct cfq_data
*cfqd
, struct cfq_group
*cfqg
)
1308 struct cfq_rb_root
*st
= &cfqd
->grp_service_tree
;
1309 struct cfq_group
*__cfqg
;
1313 if (!RB_EMPTY_NODE(&cfqg
->rb_node
))
1317 * Currently put the group at the end. Later implement something
1318 * so that groups get lesser vtime based on their weights, so that
1319 * if group does not loose all if it was not continuously backlogged.
1321 n
= rb_last(&st
->rb
);
1323 __cfqg
= rb_entry_cfqg(n
);
1324 cfqg
->vdisktime
= __cfqg
->vdisktime
+ CFQ_IDLE_DELAY
;
1326 cfqg
->vdisktime
= st
->min_vdisktime
;
1327 cfq_group_service_tree_add(st
, cfqg
);
1331 cfq_group_service_tree_del(struct cfq_rb_root
*st
, struct cfq_group
*cfqg
)
1333 struct cfq_group
*pos
= cfqg
;
1337 * Undo activation from cfq_group_service_tree_add(). Deactivate
1338 * @cfqg and propagate deactivation upwards.
1340 propagate
= !--pos
->nr_active
;
1341 pos
->children_weight
-= pos
->leaf_weight
;
1344 struct cfq_group
*parent
= cfqg_flat_parent(pos
);
1346 /* @pos has 0 nr_active at this point */
1347 WARN_ON_ONCE(pos
->children_weight
);
1353 propagate
= !--parent
->nr_active
;
1354 parent
->children_weight
-= pos
->weight
;
1358 /* remove from the service tree */
1359 if (!RB_EMPTY_NODE(&cfqg
->rb_node
))
1360 cfq_rb_erase(&cfqg
->rb_node
, st
);
1364 cfq_group_notify_queue_del(struct cfq_data
*cfqd
, struct cfq_group
*cfqg
)
1366 struct cfq_rb_root
*st
= &cfqd
->grp_service_tree
;
1368 BUG_ON(cfqg
->nr_cfqq
< 1);
1371 /* If there are other cfq queues under this group, don't delete it */
1375 cfq_log_cfqg(cfqd
, cfqg
, "del_from_rr group");
1376 cfq_group_service_tree_del(st
, cfqg
);
1377 cfqg
->saved_wl_slice
= 0;
1378 cfqg_stats_update_dequeue(cfqg
);
1381 static inline unsigned int cfq_cfqq_slice_usage(struct cfq_queue
*cfqq
,
1382 unsigned int *unaccounted_time
)
1384 unsigned int slice_used
;
1387 * Queue got expired before even a single request completed or
1388 * got expired immediately after first request completion.
1390 if (!cfqq
->slice_start
|| cfqq
->slice_start
== jiffies
) {
1392 * Also charge the seek time incurred to the group, otherwise
1393 * if there are mutiple queues in the group, each can dispatch
1394 * a single request on seeky media and cause lots of seek time
1395 * and group will never know it.
1397 slice_used
= max_t(unsigned, (jiffies
- cfqq
->dispatch_start
),
1400 slice_used
= jiffies
- cfqq
->slice_start
;
1401 if (slice_used
> cfqq
->allocated_slice
) {
1402 *unaccounted_time
= slice_used
- cfqq
->allocated_slice
;
1403 slice_used
= cfqq
->allocated_slice
;
1405 if (time_after(cfqq
->slice_start
, cfqq
->dispatch_start
))
1406 *unaccounted_time
+= cfqq
->slice_start
-
1407 cfqq
->dispatch_start
;
1413 static void cfq_group_served(struct cfq_data
*cfqd
, struct cfq_group
*cfqg
,
1414 struct cfq_queue
*cfqq
)
1416 struct cfq_rb_root
*st
= &cfqd
->grp_service_tree
;
1417 unsigned int used_sl
, charge
, unaccounted_sl
= 0;
1418 int nr_sync
= cfqg
->nr_cfqq
- cfqg_busy_async_queues(cfqd
, cfqg
)
1419 - cfqg
->service_tree_idle
.count
;
1422 BUG_ON(nr_sync
< 0);
1423 used_sl
= charge
= cfq_cfqq_slice_usage(cfqq
, &unaccounted_sl
);
1425 if (iops_mode(cfqd
))
1426 charge
= cfqq
->slice_dispatch
;
1427 else if (!cfq_cfqq_sync(cfqq
) && !nr_sync
)
1428 charge
= cfqq
->allocated_slice
;
1431 * Can't update vdisktime while on service tree and cfqg->vfraction
1432 * is valid only while on it. Cache vfr, leave the service tree,
1433 * update vdisktime and go back on. The re-addition to the tree
1434 * will also update the weights as necessary.
1436 vfr
= cfqg
->vfraction
;
1437 cfq_group_service_tree_del(st
, cfqg
);
1438 cfqg
->vdisktime
+= cfqg_scale_charge(charge
, vfr
);
1439 cfq_group_service_tree_add(st
, cfqg
);
1441 /* This group is being expired. Save the context */
1442 if (time_after(cfqd
->workload_expires
, jiffies
)) {
1443 cfqg
->saved_wl_slice
= cfqd
->workload_expires
1445 cfqg
->saved_wl_type
= cfqd
->serving_wl_type
;
1446 cfqg
->saved_wl_class
= cfqd
->serving_wl_class
;
1448 cfqg
->saved_wl_slice
= 0;
1450 cfq_log_cfqg(cfqd
, cfqg
, "served: vt=%llu min_vt=%llu", cfqg
->vdisktime
,
1452 cfq_log_cfqq(cfqq
->cfqd
, cfqq
,
1453 "sl_used=%u disp=%u charge=%u iops=%u sect=%lu",
1454 used_sl
, cfqq
->slice_dispatch
, charge
,
1455 iops_mode(cfqd
), cfqq
->nr_sectors
);
1456 cfqg_stats_update_timeslice_used(cfqg
, used_sl
, unaccounted_sl
);
1457 cfqg_stats_set_start_empty_time(cfqg
);
1461 * cfq_init_cfqg_base - initialize base part of a cfq_group
1462 * @cfqg: cfq_group to initialize
1464 * Initialize the base part which is used whether %CONFIG_CFQ_GROUP_IOSCHED
1465 * is enabled or not.
1467 static void cfq_init_cfqg_base(struct cfq_group
*cfqg
)
1469 struct cfq_rb_root
*st
;
1472 for_each_cfqg_st(cfqg
, i
, j
, st
)
1474 RB_CLEAR_NODE(&cfqg
->rb_node
);
1476 cfqg
->ttime
.last_end_request
= jiffies
;
1479 #ifdef CONFIG_CFQ_GROUP_IOSCHED
1480 static void cfq_pd_init(struct blkcg_gq
*blkg
)
1482 struct cfq_group
*cfqg
= blkg_to_cfqg(blkg
);
1484 cfq_init_cfqg_base(cfqg
);
1485 cfqg
->weight
= blkg
->blkcg
->cfq_weight
;
1486 cfqg
->leaf_weight
= blkg
->blkcg
->cfq_leaf_weight
;
1490 * Search for the cfq group current task belongs to. request_queue lock must
1493 static struct cfq_group
*cfq_lookup_create_cfqg(struct cfq_data
*cfqd
,
1494 struct blkcg
*blkcg
)
1496 struct request_queue
*q
= cfqd
->queue
;
1497 struct cfq_group
*cfqg
= NULL
;
1499 /* avoid lookup for the common case where there's no blkcg */
1500 if (blkcg
== &blkcg_root
) {
1501 cfqg
= cfqd
->root_group
;
1503 struct blkcg_gq
*blkg
;
1505 blkg
= blkg_lookup_create(blkcg
, q
);
1507 cfqg
= blkg_to_cfqg(blkg
);
1513 static void cfq_link_cfqq_cfqg(struct cfq_queue
*cfqq
, struct cfq_group
*cfqg
)
1515 /* Currently, all async queues are mapped to root group */
1516 if (!cfq_cfqq_sync(cfqq
))
1517 cfqg
= cfqq
->cfqd
->root_group
;
1520 /* cfqq reference on cfqg */
1524 static u64
cfqg_prfill_weight_device(struct seq_file
*sf
,
1525 struct blkg_policy_data
*pd
, int off
)
1527 struct cfq_group
*cfqg
= pd_to_cfqg(pd
);
1529 if (!cfqg
->dev_weight
)
1531 return __blkg_prfill_u64(sf
, pd
, cfqg
->dev_weight
);
1534 static int cfqg_print_weight_device(struct cgroup
*cgrp
, struct cftype
*cft
,
1535 struct seq_file
*sf
)
1537 blkcg_print_blkgs(sf
, cgroup_to_blkcg(cgrp
),
1538 cfqg_prfill_weight_device
, &blkcg_policy_cfq
, 0,
1543 static u64
cfqg_prfill_leaf_weight_device(struct seq_file
*sf
,
1544 struct blkg_policy_data
*pd
, int off
)
1546 struct cfq_group
*cfqg
= pd_to_cfqg(pd
);
1548 if (!cfqg
->dev_leaf_weight
)
1550 return __blkg_prfill_u64(sf
, pd
, cfqg
->dev_leaf_weight
);
1553 static int cfqg_print_leaf_weight_device(struct cgroup
*cgrp
,
1555 struct seq_file
*sf
)
1557 blkcg_print_blkgs(sf
, cgroup_to_blkcg(cgrp
),
1558 cfqg_prfill_leaf_weight_device
, &blkcg_policy_cfq
, 0,
1563 static int cfq_print_weight(struct cgroup
*cgrp
, struct cftype
*cft
,
1564 struct seq_file
*sf
)
1566 seq_printf(sf
, "%u\n", cgroup_to_blkcg(cgrp
)->cfq_weight
);
1570 static int cfq_print_leaf_weight(struct cgroup
*cgrp
, struct cftype
*cft
,
1571 struct seq_file
*sf
)
1573 seq_printf(sf
, "%u\n",
1574 cgroup_to_blkcg(cgrp
)->cfq_leaf_weight
);
1578 static int __cfqg_set_weight_device(struct cgroup
*cgrp
, struct cftype
*cft
,
1579 const char *buf
, bool is_leaf_weight
)
1581 struct blkcg
*blkcg
= cgroup_to_blkcg(cgrp
);
1582 struct blkg_conf_ctx ctx
;
1583 struct cfq_group
*cfqg
;
1586 ret
= blkg_conf_prep(blkcg
, &blkcg_policy_cfq
, buf
, &ctx
);
1591 cfqg
= blkg_to_cfqg(ctx
.blkg
);
1592 if (!ctx
.v
|| (ctx
.v
>= CFQ_WEIGHT_MIN
&& ctx
.v
<= CFQ_WEIGHT_MAX
)) {
1593 if (!is_leaf_weight
) {
1594 cfqg
->dev_weight
= ctx
.v
;
1595 cfqg
->new_weight
= ctx
.v
?: blkcg
->cfq_weight
;
1597 cfqg
->dev_leaf_weight
= ctx
.v
;
1598 cfqg
->new_leaf_weight
= ctx
.v
?: blkcg
->cfq_leaf_weight
;
1603 blkg_conf_finish(&ctx
);
1607 static int cfqg_set_weight_device(struct cgroup
*cgrp
, struct cftype
*cft
,
1610 return __cfqg_set_weight_device(cgrp
, cft
, buf
, false);
1613 static int cfqg_set_leaf_weight_device(struct cgroup
*cgrp
, struct cftype
*cft
,
1616 return __cfqg_set_weight_device(cgrp
, cft
, buf
, true);
1619 static int __cfq_set_weight(struct cgroup
*cgrp
, struct cftype
*cft
, u64 val
,
1620 bool is_leaf_weight
)
1622 struct blkcg
*blkcg
= cgroup_to_blkcg(cgrp
);
1623 struct blkcg_gq
*blkg
;
1624 struct hlist_node
*n
;
1626 if (val
< CFQ_WEIGHT_MIN
|| val
> CFQ_WEIGHT_MAX
)
1629 spin_lock_irq(&blkcg
->lock
);
1631 if (!is_leaf_weight
)
1632 blkcg
->cfq_weight
= val
;
1634 blkcg
->cfq_leaf_weight
= val
;
1636 hlist_for_each_entry(blkg
, n
, &blkcg
->blkg_list
, blkcg_node
) {
1637 struct cfq_group
*cfqg
= blkg_to_cfqg(blkg
);
1642 if (!is_leaf_weight
) {
1643 if (!cfqg
->dev_weight
)
1644 cfqg
->new_weight
= blkcg
->cfq_weight
;
1646 if (!cfqg
->dev_leaf_weight
)
1647 cfqg
->new_leaf_weight
= blkcg
->cfq_leaf_weight
;
1651 spin_unlock_irq(&blkcg
->lock
);
1655 static int cfq_set_weight(struct cgroup
*cgrp
, struct cftype
*cft
, u64 val
)
1657 return __cfq_set_weight(cgrp
, cft
, val
, false);
1660 static int cfq_set_leaf_weight(struct cgroup
*cgrp
, struct cftype
*cft
, u64 val
)
1662 return __cfq_set_weight(cgrp
, cft
, val
, true);
1665 static int cfqg_print_stat(struct cgroup
*cgrp
, struct cftype
*cft
,
1666 struct seq_file
*sf
)
1668 struct blkcg
*blkcg
= cgroup_to_blkcg(cgrp
);
1670 blkcg_print_blkgs(sf
, blkcg
, blkg_prfill_stat
, &blkcg_policy_cfq
,
1671 cft
->private, false);
1675 static int cfqg_print_rwstat(struct cgroup
*cgrp
, struct cftype
*cft
,
1676 struct seq_file
*sf
)
1678 struct blkcg
*blkcg
= cgroup_to_blkcg(cgrp
);
1680 blkcg_print_blkgs(sf
, blkcg
, blkg_prfill_rwstat
, &blkcg_policy_cfq
,
1681 cft
->private, true);
1685 #ifdef CONFIG_DEBUG_BLK_CGROUP
1686 static u64
cfqg_prfill_avg_queue_size(struct seq_file
*sf
,
1687 struct blkg_policy_data
*pd
, int off
)
1689 struct cfq_group
*cfqg
= pd_to_cfqg(pd
);
1690 u64 samples
= blkg_stat_read(&cfqg
->stats
.avg_queue_size_samples
);
1694 v
= blkg_stat_read(&cfqg
->stats
.avg_queue_size_sum
);
1697 __blkg_prfill_u64(sf
, pd
, v
);
1701 /* print avg_queue_size */
1702 static int cfqg_print_avg_queue_size(struct cgroup
*cgrp
, struct cftype
*cft
,
1703 struct seq_file
*sf
)
1705 struct blkcg
*blkcg
= cgroup_to_blkcg(cgrp
);
1707 blkcg_print_blkgs(sf
, blkcg
, cfqg_prfill_avg_queue_size
,
1708 &blkcg_policy_cfq
, 0, false);
1711 #endif /* CONFIG_DEBUG_BLK_CGROUP */
1713 static struct cftype cfq_blkcg_files
[] = {
1714 /* on root, weight is mapped to leaf_weight */
1716 .name
= "weight_device",
1717 .flags
= CFTYPE_ONLY_ON_ROOT
,
1718 .read_seq_string
= cfqg_print_leaf_weight_device
,
1719 .write_string
= cfqg_set_leaf_weight_device
,
1720 .max_write_len
= 256,
1724 .flags
= CFTYPE_ONLY_ON_ROOT
,
1725 .read_seq_string
= cfq_print_leaf_weight
,
1726 .write_u64
= cfq_set_leaf_weight
,
1729 /* no such mapping necessary for !roots */
1731 .name
= "weight_device",
1732 .flags
= CFTYPE_NOT_ON_ROOT
,
1733 .read_seq_string
= cfqg_print_weight_device
,
1734 .write_string
= cfqg_set_weight_device
,
1735 .max_write_len
= 256,
1739 .flags
= CFTYPE_NOT_ON_ROOT
,
1740 .read_seq_string
= cfq_print_weight
,
1741 .write_u64
= cfq_set_weight
,
1745 .name
= "leaf_weight_device",
1746 .read_seq_string
= cfqg_print_leaf_weight_device
,
1747 .write_string
= cfqg_set_leaf_weight_device
,
1748 .max_write_len
= 256,
1751 .name
= "leaf_weight",
1752 .read_seq_string
= cfq_print_leaf_weight
,
1753 .write_u64
= cfq_set_leaf_weight
,
1758 .private = offsetof(struct cfq_group
, stats
.time
),
1759 .read_seq_string
= cfqg_print_stat
,
1763 .private = offsetof(struct cfq_group
, stats
.sectors
),
1764 .read_seq_string
= cfqg_print_stat
,
1767 .name
= "io_service_bytes",
1768 .private = offsetof(struct cfq_group
, stats
.service_bytes
),
1769 .read_seq_string
= cfqg_print_rwstat
,
1772 .name
= "io_serviced",
1773 .private = offsetof(struct cfq_group
, stats
.serviced
),
1774 .read_seq_string
= cfqg_print_rwstat
,
1777 .name
= "io_service_time",
1778 .private = offsetof(struct cfq_group
, stats
.service_time
),
1779 .read_seq_string
= cfqg_print_rwstat
,
1782 .name
= "io_wait_time",
1783 .private = offsetof(struct cfq_group
, stats
.wait_time
),
1784 .read_seq_string
= cfqg_print_rwstat
,
1787 .name
= "io_merged",
1788 .private = offsetof(struct cfq_group
, stats
.merged
),
1789 .read_seq_string
= cfqg_print_rwstat
,
1792 .name
= "io_queued",
1793 .private = offsetof(struct cfq_group
, stats
.queued
),
1794 .read_seq_string
= cfqg_print_rwstat
,
1796 #ifdef CONFIG_DEBUG_BLK_CGROUP
1798 .name
= "avg_queue_size",
1799 .read_seq_string
= cfqg_print_avg_queue_size
,
1802 .name
= "group_wait_time",
1803 .private = offsetof(struct cfq_group
, stats
.group_wait_time
),
1804 .read_seq_string
= cfqg_print_stat
,
1807 .name
= "idle_time",
1808 .private = offsetof(struct cfq_group
, stats
.idle_time
),
1809 .read_seq_string
= cfqg_print_stat
,
1812 .name
= "empty_time",
1813 .private = offsetof(struct cfq_group
, stats
.empty_time
),
1814 .read_seq_string
= cfqg_print_stat
,
1818 .private = offsetof(struct cfq_group
, stats
.dequeue
),
1819 .read_seq_string
= cfqg_print_stat
,
1822 .name
= "unaccounted_time",
1823 .private = offsetof(struct cfq_group
, stats
.unaccounted_time
),
1824 .read_seq_string
= cfqg_print_stat
,
1826 #endif /* CONFIG_DEBUG_BLK_CGROUP */
1829 #else /* GROUP_IOSCHED */
1830 static struct cfq_group
*cfq_lookup_create_cfqg(struct cfq_data
*cfqd
,
1831 struct blkcg
*blkcg
)
1833 return cfqd
->root_group
;
1837 cfq_link_cfqq_cfqg(struct cfq_queue
*cfqq
, struct cfq_group
*cfqg
) {
1841 #endif /* GROUP_IOSCHED */
1844 * The cfqd->service_trees holds all pending cfq_queue's that have
1845 * requests waiting to be processed. It is sorted in the order that
1846 * we will service the queues.
1848 static void cfq_service_tree_add(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
1851 struct rb_node
**p
, *parent
;
1852 struct cfq_queue
*__cfqq
;
1853 unsigned long rb_key
;
1854 struct cfq_rb_root
*st
;
1858 st
= st_for(cfqq
->cfqg
, cfqq_class(cfqq
), cfqq_type(cfqq
));
1859 if (cfq_class_idle(cfqq
)) {
1860 rb_key
= CFQ_IDLE_DELAY
;
1861 parent
= rb_last(&st
->rb
);
1862 if (parent
&& parent
!= &cfqq
->rb_node
) {
1863 __cfqq
= rb_entry(parent
, struct cfq_queue
, rb_node
);
1864 rb_key
+= __cfqq
->rb_key
;
1867 } else if (!add_front
) {
1869 * Get our rb key offset. Subtract any residual slice
1870 * value carried from last service. A negative resid
1871 * count indicates slice overrun, and this should position
1872 * the next service time further away in the tree.
1874 rb_key
= cfq_slice_offset(cfqd
, cfqq
) + jiffies
;
1875 rb_key
-= cfqq
->slice_resid
;
1876 cfqq
->slice_resid
= 0;
1879 __cfqq
= cfq_rb_first(st
);
1880 rb_key
+= __cfqq
? __cfqq
->rb_key
: jiffies
;
1883 if (!RB_EMPTY_NODE(&cfqq
->rb_node
)) {
1886 * same position, nothing more to do
1888 if (rb_key
== cfqq
->rb_key
&& cfqq
->service_tree
== st
)
1891 cfq_rb_erase(&cfqq
->rb_node
, cfqq
->service_tree
);
1892 cfqq
->service_tree
= NULL
;
1897 cfqq
->service_tree
= st
;
1898 p
= &st
->rb
.rb_node
;
1901 __cfqq
= rb_entry(parent
, struct cfq_queue
, rb_node
);
1904 * sort by key, that represents service time.
1906 if (time_before(rb_key
, __cfqq
->rb_key
))
1907 p
= &parent
->rb_left
;
1909 p
= &parent
->rb_right
;
1915 st
->left
= &cfqq
->rb_node
;
1917 cfqq
->rb_key
= rb_key
;
1918 rb_link_node(&cfqq
->rb_node
, parent
, p
);
1919 rb_insert_color(&cfqq
->rb_node
, &st
->rb
);
1921 if (add_front
|| !new_cfqq
)
1923 cfq_group_notify_queue_add(cfqd
, cfqq
->cfqg
);
1926 static struct cfq_queue
*
1927 cfq_prio_tree_lookup(struct cfq_data
*cfqd
, struct rb_root
*root
,
1928 sector_t sector
, struct rb_node
**ret_parent
,
1929 struct rb_node
***rb_link
)
1931 struct rb_node
**p
, *parent
;
1932 struct cfq_queue
*cfqq
= NULL
;
1940 cfqq
= rb_entry(parent
, struct cfq_queue
, p_node
);
1943 * Sort strictly based on sector. Smallest to the left,
1944 * largest to the right.
1946 if (sector
> blk_rq_pos(cfqq
->next_rq
))
1947 n
= &(*p
)->rb_right
;
1948 else if (sector
< blk_rq_pos(cfqq
->next_rq
))
1956 *ret_parent
= parent
;
1962 static void cfq_prio_tree_add(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
1964 struct rb_node
**p
, *parent
;
1965 struct cfq_queue
*__cfqq
;
1968 rb_erase(&cfqq
->p_node
, cfqq
->p_root
);
1969 cfqq
->p_root
= NULL
;
1972 if (cfq_class_idle(cfqq
))
1977 cfqq
->p_root
= &cfqd
->prio_trees
[cfqq
->org_ioprio
];
1978 __cfqq
= cfq_prio_tree_lookup(cfqd
, cfqq
->p_root
,
1979 blk_rq_pos(cfqq
->next_rq
), &parent
, &p
);
1981 rb_link_node(&cfqq
->p_node
, parent
, p
);
1982 rb_insert_color(&cfqq
->p_node
, cfqq
->p_root
);
1984 cfqq
->p_root
= NULL
;
1988 * Update cfqq's position in the service tree.
1990 static void cfq_resort_rr_list(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
1993 * Resorting requires the cfqq to be on the RR list already.
1995 if (cfq_cfqq_on_rr(cfqq
)) {
1996 cfq_service_tree_add(cfqd
, cfqq
, 0);
1997 cfq_prio_tree_add(cfqd
, cfqq
);
2002 * add to busy list of queues for service, trying to be fair in ordering
2003 * the pending list according to last request service
2005 static void cfq_add_cfqq_rr(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
2007 cfq_log_cfqq(cfqd
, cfqq
, "add_to_rr");
2008 BUG_ON(cfq_cfqq_on_rr(cfqq
));
2009 cfq_mark_cfqq_on_rr(cfqq
);
2010 cfqd
->busy_queues
++;
2011 if (cfq_cfqq_sync(cfqq
))
2012 cfqd
->busy_sync_queues
++;
2014 cfq_resort_rr_list(cfqd
, cfqq
);
2018 * Called when the cfqq no longer has requests pending, remove it from
2021 static void cfq_del_cfqq_rr(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
2023 cfq_log_cfqq(cfqd
, cfqq
, "del_from_rr");
2024 BUG_ON(!cfq_cfqq_on_rr(cfqq
));
2025 cfq_clear_cfqq_on_rr(cfqq
);
2027 if (!RB_EMPTY_NODE(&cfqq
->rb_node
)) {
2028 cfq_rb_erase(&cfqq
->rb_node
, cfqq
->service_tree
);
2029 cfqq
->service_tree
= NULL
;
2032 rb_erase(&cfqq
->p_node
, cfqq
->p_root
);
2033 cfqq
->p_root
= NULL
;
2036 cfq_group_notify_queue_del(cfqd
, cfqq
->cfqg
);
2037 BUG_ON(!cfqd
->busy_queues
);
2038 cfqd
->busy_queues
--;
2039 if (cfq_cfqq_sync(cfqq
))
2040 cfqd
->busy_sync_queues
--;
2044 * rb tree support functions
2046 static void cfq_del_rq_rb(struct request
*rq
)
2048 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
2049 const int sync
= rq_is_sync(rq
);
2051 BUG_ON(!cfqq
->queued
[sync
]);
2052 cfqq
->queued
[sync
]--;
2054 elv_rb_del(&cfqq
->sort_list
, rq
);
2056 if (cfq_cfqq_on_rr(cfqq
) && RB_EMPTY_ROOT(&cfqq
->sort_list
)) {
2058 * Queue will be deleted from service tree when we actually
2059 * expire it later. Right now just remove it from prio tree
2063 rb_erase(&cfqq
->p_node
, cfqq
->p_root
);
2064 cfqq
->p_root
= NULL
;
2069 static void cfq_add_rq_rb(struct request
*rq
)
2071 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
2072 struct cfq_data
*cfqd
= cfqq
->cfqd
;
2073 struct request
*prev
;
2075 cfqq
->queued
[rq_is_sync(rq
)]++;
2077 elv_rb_add(&cfqq
->sort_list
, rq
);
2079 if (!cfq_cfqq_on_rr(cfqq
))
2080 cfq_add_cfqq_rr(cfqd
, cfqq
);
2083 * check if this request is a better next-serve candidate
2085 prev
= cfqq
->next_rq
;
2086 cfqq
->next_rq
= cfq_choose_req(cfqd
, cfqq
->next_rq
, rq
, cfqd
->last_position
);
2089 * adjust priority tree position, if ->next_rq changes
2091 if (prev
!= cfqq
->next_rq
)
2092 cfq_prio_tree_add(cfqd
, cfqq
);
2094 BUG_ON(!cfqq
->next_rq
);
2097 static void cfq_reposition_rq_rb(struct cfq_queue
*cfqq
, struct request
*rq
)
2099 elv_rb_del(&cfqq
->sort_list
, rq
);
2100 cfqq
->queued
[rq_is_sync(rq
)]--;
2101 cfqg_stats_update_io_remove(RQ_CFQG(rq
), rq
->cmd_flags
);
2103 cfqg_stats_update_io_add(RQ_CFQG(rq
), cfqq
->cfqd
->serving_group
,
2107 static struct request
*
2108 cfq_find_rq_fmerge(struct cfq_data
*cfqd
, struct bio
*bio
)
2110 struct task_struct
*tsk
= current
;
2111 struct cfq_io_cq
*cic
;
2112 struct cfq_queue
*cfqq
;
2114 cic
= cfq_cic_lookup(cfqd
, tsk
->io_context
);
2118 cfqq
= cic_to_cfqq(cic
, cfq_bio_sync(bio
));
2120 sector_t sector
= bio
->bi_sector
+ bio_sectors(bio
);
2122 return elv_rb_find(&cfqq
->sort_list
, sector
);
2128 static void cfq_activate_request(struct request_queue
*q
, struct request
*rq
)
2130 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
2132 cfqd
->rq_in_driver
++;
2133 cfq_log_cfqq(cfqd
, RQ_CFQQ(rq
), "activate rq, drv=%d",
2134 cfqd
->rq_in_driver
);
2136 cfqd
->last_position
= blk_rq_pos(rq
) + blk_rq_sectors(rq
);
2139 static void cfq_deactivate_request(struct request_queue
*q
, struct request
*rq
)
2141 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
2143 WARN_ON(!cfqd
->rq_in_driver
);
2144 cfqd
->rq_in_driver
--;
2145 cfq_log_cfqq(cfqd
, RQ_CFQQ(rq
), "deactivate rq, drv=%d",
2146 cfqd
->rq_in_driver
);
2149 static void cfq_remove_request(struct request
*rq
)
2151 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
2153 if (cfqq
->next_rq
== rq
)
2154 cfqq
->next_rq
= cfq_find_next_rq(cfqq
->cfqd
, cfqq
, rq
);
2156 list_del_init(&rq
->queuelist
);
2159 cfqq
->cfqd
->rq_queued
--;
2160 cfqg_stats_update_io_remove(RQ_CFQG(rq
), rq
->cmd_flags
);
2161 if (rq
->cmd_flags
& REQ_PRIO
) {
2162 WARN_ON(!cfqq
->prio_pending
);
2163 cfqq
->prio_pending
--;
2167 static int cfq_merge(struct request_queue
*q
, struct request
**req
,
2170 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
2171 struct request
*__rq
;
2173 __rq
= cfq_find_rq_fmerge(cfqd
, bio
);
2174 if (__rq
&& elv_rq_merge_ok(__rq
, bio
)) {
2176 return ELEVATOR_FRONT_MERGE
;
2179 return ELEVATOR_NO_MERGE
;
2182 static void cfq_merged_request(struct request_queue
*q
, struct request
*req
,
2185 if (type
== ELEVATOR_FRONT_MERGE
) {
2186 struct cfq_queue
*cfqq
= RQ_CFQQ(req
);
2188 cfq_reposition_rq_rb(cfqq
, req
);
2192 static void cfq_bio_merged(struct request_queue
*q
, struct request
*req
,
2195 cfqg_stats_update_io_merged(RQ_CFQG(req
), bio
->bi_rw
);
2199 cfq_merged_requests(struct request_queue
*q
, struct request
*rq
,
2200 struct request
*next
)
2202 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
2203 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
2206 * reposition in fifo if next is older than rq
2208 if (!list_empty(&rq
->queuelist
) && !list_empty(&next
->queuelist
) &&
2209 time_before(rq_fifo_time(next
), rq_fifo_time(rq
)) &&
2210 cfqq
== RQ_CFQQ(next
)) {
2211 list_move(&rq
->queuelist
, &next
->queuelist
);
2212 rq_set_fifo_time(rq
, rq_fifo_time(next
));
2215 if (cfqq
->next_rq
== next
)
2217 cfq_remove_request(next
);
2218 cfqg_stats_update_io_merged(RQ_CFQG(rq
), next
->cmd_flags
);
2220 cfqq
= RQ_CFQQ(next
);
2222 * all requests of this queue are merged to other queues, delete it
2223 * from the service tree. If it's the active_queue,
2224 * cfq_dispatch_requests() will choose to expire it or do idle
2226 if (cfq_cfqq_on_rr(cfqq
) && RB_EMPTY_ROOT(&cfqq
->sort_list
) &&
2227 cfqq
!= cfqd
->active_queue
)
2228 cfq_del_cfqq_rr(cfqd
, cfqq
);
2231 static int cfq_allow_merge(struct request_queue
*q
, struct request
*rq
,
2234 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
2235 struct cfq_io_cq
*cic
;
2236 struct cfq_queue
*cfqq
;
2239 * Disallow merge of a sync bio into an async request.
2241 if (cfq_bio_sync(bio
) && !rq_is_sync(rq
))
2245 * Lookup the cfqq that this bio will be queued with and allow
2246 * merge only if rq is queued there.
2248 cic
= cfq_cic_lookup(cfqd
, current
->io_context
);
2252 cfqq
= cic_to_cfqq(cic
, cfq_bio_sync(bio
));
2253 return cfqq
== RQ_CFQQ(rq
);
2256 static inline void cfq_del_timer(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
2258 del_timer(&cfqd
->idle_slice_timer
);
2259 cfqg_stats_update_idle_time(cfqq
->cfqg
);
2262 static void __cfq_set_active_queue(struct cfq_data
*cfqd
,
2263 struct cfq_queue
*cfqq
)
2266 cfq_log_cfqq(cfqd
, cfqq
, "set_active wl_class:%d wl_type:%d",
2267 cfqd
->serving_wl_class
, cfqd
->serving_wl_type
);
2268 cfqg_stats_update_avg_queue_size(cfqq
->cfqg
);
2269 cfqq
->slice_start
= 0;
2270 cfqq
->dispatch_start
= jiffies
;
2271 cfqq
->allocated_slice
= 0;
2272 cfqq
->slice_end
= 0;
2273 cfqq
->slice_dispatch
= 0;
2274 cfqq
->nr_sectors
= 0;
2276 cfq_clear_cfqq_wait_request(cfqq
);
2277 cfq_clear_cfqq_must_dispatch(cfqq
);
2278 cfq_clear_cfqq_must_alloc_slice(cfqq
);
2279 cfq_clear_cfqq_fifo_expire(cfqq
);
2280 cfq_mark_cfqq_slice_new(cfqq
);
2282 cfq_del_timer(cfqd
, cfqq
);
2285 cfqd
->active_queue
= cfqq
;
2289 * current cfqq expired its slice (or was too idle), select new one
2292 __cfq_slice_expired(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
2295 cfq_log_cfqq(cfqd
, cfqq
, "slice expired t=%d", timed_out
);
2297 if (cfq_cfqq_wait_request(cfqq
))
2298 cfq_del_timer(cfqd
, cfqq
);
2300 cfq_clear_cfqq_wait_request(cfqq
);
2301 cfq_clear_cfqq_wait_busy(cfqq
);
2304 * If this cfqq is shared between multiple processes, check to
2305 * make sure that those processes are still issuing I/Os within
2306 * the mean seek distance. If not, it may be time to break the
2307 * queues apart again.
2309 if (cfq_cfqq_coop(cfqq
) && CFQQ_SEEKY(cfqq
))
2310 cfq_mark_cfqq_split_coop(cfqq
);
2313 * store what was left of this slice, if the queue idled/timed out
2316 if (cfq_cfqq_slice_new(cfqq
))
2317 cfqq
->slice_resid
= cfq_scaled_cfqq_slice(cfqd
, cfqq
);
2319 cfqq
->slice_resid
= cfqq
->slice_end
- jiffies
;
2320 cfq_log_cfqq(cfqd
, cfqq
, "resid=%ld", cfqq
->slice_resid
);
2323 cfq_group_served(cfqd
, cfqq
->cfqg
, cfqq
);
2325 if (cfq_cfqq_on_rr(cfqq
) && RB_EMPTY_ROOT(&cfqq
->sort_list
))
2326 cfq_del_cfqq_rr(cfqd
, cfqq
);
2328 cfq_resort_rr_list(cfqd
, cfqq
);
2330 if (cfqq
== cfqd
->active_queue
)
2331 cfqd
->active_queue
= NULL
;
2333 if (cfqd
->active_cic
) {
2334 put_io_context(cfqd
->active_cic
->icq
.ioc
);
2335 cfqd
->active_cic
= NULL
;
2339 static inline void cfq_slice_expired(struct cfq_data
*cfqd
, bool timed_out
)
2341 struct cfq_queue
*cfqq
= cfqd
->active_queue
;
2344 __cfq_slice_expired(cfqd
, cfqq
, timed_out
);
2348 * Get next queue for service. Unless we have a queue preemption,
2349 * we'll simply select the first cfqq in the service tree.
2351 static struct cfq_queue
*cfq_get_next_queue(struct cfq_data
*cfqd
)
2353 struct cfq_rb_root
*st
= st_for(cfqd
->serving_group
,
2354 cfqd
->serving_wl_class
, cfqd
->serving_wl_type
);
2356 if (!cfqd
->rq_queued
)
2359 /* There is nothing to dispatch */
2362 if (RB_EMPTY_ROOT(&st
->rb
))
2364 return cfq_rb_first(st
);
2367 static struct cfq_queue
*cfq_get_next_queue_forced(struct cfq_data
*cfqd
)
2369 struct cfq_group
*cfqg
;
2370 struct cfq_queue
*cfqq
;
2372 struct cfq_rb_root
*st
;
2374 if (!cfqd
->rq_queued
)
2377 cfqg
= cfq_get_next_cfqg(cfqd
);
2381 for_each_cfqg_st(cfqg
, i
, j
, st
)
2382 if ((cfqq
= cfq_rb_first(st
)) != NULL
)
2388 * Get and set a new active queue for service.
2390 static struct cfq_queue
*cfq_set_active_queue(struct cfq_data
*cfqd
,
2391 struct cfq_queue
*cfqq
)
2394 cfqq
= cfq_get_next_queue(cfqd
);
2396 __cfq_set_active_queue(cfqd
, cfqq
);
2400 static inline sector_t
cfq_dist_from_last(struct cfq_data
*cfqd
,
2403 if (blk_rq_pos(rq
) >= cfqd
->last_position
)
2404 return blk_rq_pos(rq
) - cfqd
->last_position
;
2406 return cfqd
->last_position
- blk_rq_pos(rq
);
2409 static inline int cfq_rq_close(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
2412 return cfq_dist_from_last(cfqd
, rq
) <= CFQQ_CLOSE_THR
;
2415 static struct cfq_queue
*cfqq_close(struct cfq_data
*cfqd
,
2416 struct cfq_queue
*cur_cfqq
)
2418 struct rb_root
*root
= &cfqd
->prio_trees
[cur_cfqq
->org_ioprio
];
2419 struct rb_node
*parent
, *node
;
2420 struct cfq_queue
*__cfqq
;
2421 sector_t sector
= cfqd
->last_position
;
2423 if (RB_EMPTY_ROOT(root
))
2427 * First, if we find a request starting at the end of the last
2428 * request, choose it.
2430 __cfqq
= cfq_prio_tree_lookup(cfqd
, root
, sector
, &parent
, NULL
);
2435 * If the exact sector wasn't found, the parent of the NULL leaf
2436 * will contain the closest sector.
2438 __cfqq
= rb_entry(parent
, struct cfq_queue
, p_node
);
2439 if (cfq_rq_close(cfqd
, cur_cfqq
, __cfqq
->next_rq
))
2442 if (blk_rq_pos(__cfqq
->next_rq
) < sector
)
2443 node
= rb_next(&__cfqq
->p_node
);
2445 node
= rb_prev(&__cfqq
->p_node
);
2449 __cfqq
= rb_entry(node
, struct cfq_queue
, p_node
);
2450 if (cfq_rq_close(cfqd
, cur_cfqq
, __cfqq
->next_rq
))
2458 * cur_cfqq - passed in so that we don't decide that the current queue is
2459 * closely cooperating with itself.
2461 * So, basically we're assuming that that cur_cfqq has dispatched at least
2462 * one request, and that cfqd->last_position reflects a position on the disk
2463 * associated with the I/O issued by cur_cfqq. I'm not sure this is a valid
2466 static struct cfq_queue
*cfq_close_cooperator(struct cfq_data
*cfqd
,
2467 struct cfq_queue
*cur_cfqq
)
2469 struct cfq_queue
*cfqq
;
2471 if (cfq_class_idle(cur_cfqq
))
2473 if (!cfq_cfqq_sync(cur_cfqq
))
2475 if (CFQQ_SEEKY(cur_cfqq
))
2479 * Don't search priority tree if it's the only queue in the group.
2481 if (cur_cfqq
->cfqg
->nr_cfqq
== 1)
2485 * We should notice if some of the queues are cooperating, eg
2486 * working closely on the same area of the disk. In that case,
2487 * we can group them together and don't waste time idling.
2489 cfqq
= cfqq_close(cfqd
, cur_cfqq
);
2493 /* If new queue belongs to different cfq_group, don't choose it */
2494 if (cur_cfqq
->cfqg
!= cfqq
->cfqg
)
2498 * It only makes sense to merge sync queues.
2500 if (!cfq_cfqq_sync(cfqq
))
2502 if (CFQQ_SEEKY(cfqq
))
2506 * Do not merge queues of different priority classes
2508 if (cfq_class_rt(cfqq
) != cfq_class_rt(cur_cfqq
))
2515 * Determine whether we should enforce idle window for this queue.
2518 static bool cfq_should_idle(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
2520 enum wl_class_t wl_class
= cfqq_class(cfqq
);
2521 struct cfq_rb_root
*st
= cfqq
->service_tree
;
2526 if (!cfqd
->cfq_slice_idle
)
2529 /* We never do for idle class queues. */
2530 if (wl_class
== IDLE_WORKLOAD
)
2533 /* We do for queues that were marked with idle window flag. */
2534 if (cfq_cfqq_idle_window(cfqq
) &&
2535 !(blk_queue_nonrot(cfqd
->queue
) && cfqd
->hw_tag
))
2539 * Otherwise, we do only if they are the last ones
2540 * in their service tree.
2542 if (st
->count
== 1 && cfq_cfqq_sync(cfqq
) &&
2543 !cfq_io_thinktime_big(cfqd
, &st
->ttime
, false))
2545 cfq_log_cfqq(cfqd
, cfqq
, "Not idling. st->count:%d", st
->count
);
2549 static void cfq_arm_slice_timer(struct cfq_data
*cfqd
)
2551 struct cfq_queue
*cfqq
= cfqd
->active_queue
;
2552 struct cfq_io_cq
*cic
;
2553 unsigned long sl
, group_idle
= 0;
2556 * SSD device without seek penalty, disable idling. But only do so
2557 * for devices that support queuing, otherwise we still have a problem
2558 * with sync vs async workloads.
2560 if (blk_queue_nonrot(cfqd
->queue
) && cfqd
->hw_tag
)
2563 WARN_ON(!RB_EMPTY_ROOT(&cfqq
->sort_list
));
2564 WARN_ON(cfq_cfqq_slice_new(cfqq
));
2567 * idle is disabled, either manually or by past process history
2569 if (!cfq_should_idle(cfqd
, cfqq
)) {
2570 /* no queue idling. Check for group idling */
2571 if (cfqd
->cfq_group_idle
)
2572 group_idle
= cfqd
->cfq_group_idle
;
2578 * still active requests from this queue, don't idle
2580 if (cfqq
->dispatched
)
2584 * task has exited, don't wait
2586 cic
= cfqd
->active_cic
;
2587 if (!cic
|| !atomic_read(&cic
->icq
.ioc
->active_ref
))
2591 * If our average think time is larger than the remaining time
2592 * slice, then don't idle. This avoids overrunning the allotted
2595 if (sample_valid(cic
->ttime
.ttime_samples
) &&
2596 (cfqq
->slice_end
- jiffies
< cic
->ttime
.ttime_mean
)) {
2597 cfq_log_cfqq(cfqd
, cfqq
, "Not idling. think_time:%lu",
2598 cic
->ttime
.ttime_mean
);
2602 /* There are other queues in the group, don't do group idle */
2603 if (group_idle
&& cfqq
->cfqg
->nr_cfqq
> 1)
2606 cfq_mark_cfqq_wait_request(cfqq
);
2609 sl
= cfqd
->cfq_group_idle
;
2611 sl
= cfqd
->cfq_slice_idle
;
2613 mod_timer(&cfqd
->idle_slice_timer
, jiffies
+ sl
);
2614 cfqg_stats_set_start_idle_time(cfqq
->cfqg
);
2615 cfq_log_cfqq(cfqd
, cfqq
, "arm_idle: %lu group_idle: %d", sl
,
2616 group_idle
? 1 : 0);
2620 * Move request from internal lists to the request queue dispatch list.
2622 static void cfq_dispatch_insert(struct request_queue
*q
, struct request
*rq
)
2624 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
2625 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
2627 cfq_log_cfqq(cfqd
, cfqq
, "dispatch_insert");
2629 cfqq
->next_rq
= cfq_find_next_rq(cfqd
, cfqq
, rq
);
2630 cfq_remove_request(rq
);
2632 (RQ_CFQG(rq
))->dispatched
++;
2633 elv_dispatch_sort(q
, rq
);
2635 cfqd
->rq_in_flight
[cfq_cfqq_sync(cfqq
)]++;
2636 cfqq
->nr_sectors
+= blk_rq_sectors(rq
);
2637 cfqg_stats_update_dispatch(cfqq
->cfqg
, blk_rq_bytes(rq
), rq
->cmd_flags
);
2641 * return expired entry, or NULL to just start from scratch in rbtree
2643 static struct request
*cfq_check_fifo(struct cfq_queue
*cfqq
)
2645 struct request
*rq
= NULL
;
2647 if (cfq_cfqq_fifo_expire(cfqq
))
2650 cfq_mark_cfqq_fifo_expire(cfqq
);
2652 if (list_empty(&cfqq
->fifo
))
2655 rq
= rq_entry_fifo(cfqq
->fifo
.next
);
2656 if (time_before(jiffies
, rq_fifo_time(rq
)))
2659 cfq_log_cfqq(cfqq
->cfqd
, cfqq
, "fifo=%p", rq
);
2664 cfq_prio_to_maxrq(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
2666 const int base_rq
= cfqd
->cfq_slice_async_rq
;
2668 WARN_ON(cfqq
->ioprio
>= IOPRIO_BE_NR
);
2670 return 2 * base_rq
* (IOPRIO_BE_NR
- cfqq
->ioprio
);
2674 * Must be called with the queue_lock held.
2676 static int cfqq_process_refs(struct cfq_queue
*cfqq
)
2678 int process_refs
, io_refs
;
2680 io_refs
= cfqq
->allocated
[READ
] + cfqq
->allocated
[WRITE
];
2681 process_refs
= cfqq
->ref
- io_refs
;
2682 BUG_ON(process_refs
< 0);
2683 return process_refs
;
2686 static void cfq_setup_merge(struct cfq_queue
*cfqq
, struct cfq_queue
*new_cfqq
)
2688 int process_refs
, new_process_refs
;
2689 struct cfq_queue
*__cfqq
;
2692 * If there are no process references on the new_cfqq, then it is
2693 * unsafe to follow the ->new_cfqq chain as other cfqq's in the
2694 * chain may have dropped their last reference (not just their
2695 * last process reference).
2697 if (!cfqq_process_refs(new_cfqq
))
2700 /* Avoid a circular list and skip interim queue merges */
2701 while ((__cfqq
= new_cfqq
->new_cfqq
)) {
2707 process_refs
= cfqq_process_refs(cfqq
);
2708 new_process_refs
= cfqq_process_refs(new_cfqq
);
2710 * If the process for the cfqq has gone away, there is no
2711 * sense in merging the queues.
2713 if (process_refs
== 0 || new_process_refs
== 0)
2717 * Merge in the direction of the lesser amount of work.
2719 if (new_process_refs
>= process_refs
) {
2720 cfqq
->new_cfqq
= new_cfqq
;
2721 new_cfqq
->ref
+= process_refs
;
2723 new_cfqq
->new_cfqq
= cfqq
;
2724 cfqq
->ref
+= new_process_refs
;
2728 static enum wl_type_t
cfq_choose_wl_type(struct cfq_data
*cfqd
,
2729 struct cfq_group
*cfqg
, enum wl_class_t wl_class
)
2731 struct cfq_queue
*queue
;
2733 bool key_valid
= false;
2734 unsigned long lowest_key
= 0;
2735 enum wl_type_t cur_best
= SYNC_NOIDLE_WORKLOAD
;
2737 for (i
= 0; i
<= SYNC_WORKLOAD
; ++i
) {
2738 /* select the one with lowest rb_key */
2739 queue
= cfq_rb_first(st_for(cfqg
, wl_class
, i
));
2741 (!key_valid
|| time_before(queue
->rb_key
, lowest_key
))) {
2742 lowest_key
= queue
->rb_key
;
2752 choose_wl_class_and_type(struct cfq_data
*cfqd
, struct cfq_group
*cfqg
)
2756 struct cfq_rb_root
*st
;
2757 unsigned group_slice
;
2758 enum wl_class_t original_class
= cfqd
->serving_wl_class
;
2760 /* Choose next priority. RT > BE > IDLE */
2761 if (cfq_group_busy_queues_wl(RT_WORKLOAD
, cfqd
, cfqg
))
2762 cfqd
->serving_wl_class
= RT_WORKLOAD
;
2763 else if (cfq_group_busy_queues_wl(BE_WORKLOAD
, cfqd
, cfqg
))
2764 cfqd
->serving_wl_class
= BE_WORKLOAD
;
2766 cfqd
->serving_wl_class
= IDLE_WORKLOAD
;
2767 cfqd
->workload_expires
= jiffies
+ 1;
2771 if (original_class
!= cfqd
->serving_wl_class
)
2775 * For RT and BE, we have to choose also the type
2776 * (SYNC, SYNC_NOIDLE, ASYNC), and to compute a workload
2779 st
= st_for(cfqg
, cfqd
->serving_wl_class
, cfqd
->serving_wl_type
);
2783 * check workload expiration, and that we still have other queues ready
2785 if (count
&& !time_after(jiffies
, cfqd
->workload_expires
))
2789 /* otherwise select new workload type */
2790 cfqd
->serving_wl_type
= cfq_choose_wl_type(cfqd
, cfqg
,
2791 cfqd
->serving_wl_class
);
2792 st
= st_for(cfqg
, cfqd
->serving_wl_class
, cfqd
->serving_wl_type
);
2796 * the workload slice is computed as a fraction of target latency
2797 * proportional to the number of queues in that workload, over
2798 * all the queues in the same priority class
2800 group_slice
= cfq_group_slice(cfqd
, cfqg
);
2802 slice
= group_slice
* count
/
2803 max_t(unsigned, cfqg
->busy_queues_avg
[cfqd
->serving_wl_class
],
2804 cfq_group_busy_queues_wl(cfqd
->serving_wl_class
, cfqd
,
2807 if (cfqd
->serving_wl_type
== ASYNC_WORKLOAD
) {
2811 * Async queues are currently system wide. Just taking
2812 * proportion of queues with-in same group will lead to higher
2813 * async ratio system wide as generally root group is going
2814 * to have higher weight. A more accurate thing would be to
2815 * calculate system wide asnc/sync ratio.
2817 tmp
= cfqd
->cfq_target_latency
*
2818 cfqg_busy_async_queues(cfqd
, cfqg
);
2819 tmp
= tmp
/cfqd
->busy_queues
;
2820 slice
= min_t(unsigned, slice
, tmp
);
2822 /* async workload slice is scaled down according to
2823 * the sync/async slice ratio. */
2824 slice
= slice
* cfqd
->cfq_slice
[0] / cfqd
->cfq_slice
[1];
2826 /* sync workload slice is at least 2 * cfq_slice_idle */
2827 slice
= max(slice
, 2 * cfqd
->cfq_slice_idle
);
2829 slice
= max_t(unsigned, slice
, CFQ_MIN_TT
);
2830 cfq_log(cfqd
, "workload slice:%d", slice
);
2831 cfqd
->workload_expires
= jiffies
+ slice
;
2834 static struct cfq_group
*cfq_get_next_cfqg(struct cfq_data
*cfqd
)
2836 struct cfq_rb_root
*st
= &cfqd
->grp_service_tree
;
2837 struct cfq_group
*cfqg
;
2839 if (RB_EMPTY_ROOT(&st
->rb
))
2841 cfqg
= cfq_rb_first_group(st
);
2842 update_min_vdisktime(st
);
2846 static void cfq_choose_cfqg(struct cfq_data
*cfqd
)
2848 struct cfq_group
*cfqg
= cfq_get_next_cfqg(cfqd
);
2850 cfqd
->serving_group
= cfqg
;
2852 /* Restore the workload type data */
2853 if (cfqg
->saved_wl_slice
) {
2854 cfqd
->workload_expires
= jiffies
+ cfqg
->saved_wl_slice
;
2855 cfqd
->serving_wl_type
= cfqg
->saved_wl_type
;
2856 cfqd
->serving_wl_class
= cfqg
->saved_wl_class
;
2858 cfqd
->workload_expires
= jiffies
- 1;
2860 choose_wl_class_and_type(cfqd
, cfqg
);
2864 * Select a queue for service. If we have a current active queue,
2865 * check whether to continue servicing it, or retrieve and set a new one.
2867 static struct cfq_queue
*cfq_select_queue(struct cfq_data
*cfqd
)
2869 struct cfq_queue
*cfqq
, *new_cfqq
= NULL
;
2871 cfqq
= cfqd
->active_queue
;
2875 if (!cfqd
->rq_queued
)
2879 * We were waiting for group to get backlogged. Expire the queue
2881 if (cfq_cfqq_wait_busy(cfqq
) && !RB_EMPTY_ROOT(&cfqq
->sort_list
))
2885 * The active queue has run out of time, expire it and select new.
2887 if (cfq_slice_used(cfqq
) && !cfq_cfqq_must_dispatch(cfqq
)) {
2889 * If slice had not expired at the completion of last request
2890 * we might not have turned on wait_busy flag. Don't expire
2891 * the queue yet. Allow the group to get backlogged.
2893 * The very fact that we have used the slice, that means we
2894 * have been idling all along on this queue and it should be
2895 * ok to wait for this request to complete.
2897 if (cfqq
->cfqg
->nr_cfqq
== 1 && RB_EMPTY_ROOT(&cfqq
->sort_list
)
2898 && cfqq
->dispatched
&& cfq_should_idle(cfqd
, cfqq
)) {
2902 goto check_group_idle
;
2906 * The active queue has requests and isn't expired, allow it to
2909 if (!RB_EMPTY_ROOT(&cfqq
->sort_list
))
2913 * If another queue has a request waiting within our mean seek
2914 * distance, let it run. The expire code will check for close
2915 * cooperators and put the close queue at the front of the service
2916 * tree. If possible, merge the expiring queue with the new cfqq.
2918 new_cfqq
= cfq_close_cooperator(cfqd
, cfqq
);
2920 if (!cfqq
->new_cfqq
)
2921 cfq_setup_merge(cfqq
, new_cfqq
);
2926 * No requests pending. If the active queue still has requests in
2927 * flight or is idling for a new request, allow either of these
2928 * conditions to happen (or time out) before selecting a new queue.
2930 if (timer_pending(&cfqd
->idle_slice_timer
)) {
2936 * This is a deep seek queue, but the device is much faster than
2937 * the queue can deliver, don't idle
2939 if (CFQQ_SEEKY(cfqq
) && cfq_cfqq_idle_window(cfqq
) &&
2940 (cfq_cfqq_slice_new(cfqq
) ||
2941 (cfqq
->slice_end
- jiffies
> jiffies
- cfqq
->slice_start
))) {
2942 cfq_clear_cfqq_deep(cfqq
);
2943 cfq_clear_cfqq_idle_window(cfqq
);
2946 if (cfqq
->dispatched
&& cfq_should_idle(cfqd
, cfqq
)) {
2952 * If group idle is enabled and there are requests dispatched from
2953 * this group, wait for requests to complete.
2956 if (cfqd
->cfq_group_idle
&& cfqq
->cfqg
->nr_cfqq
== 1 &&
2957 cfqq
->cfqg
->dispatched
&&
2958 !cfq_io_thinktime_big(cfqd
, &cfqq
->cfqg
->ttime
, true)) {
2964 cfq_slice_expired(cfqd
, 0);
2967 * Current queue expired. Check if we have to switch to a new
2971 cfq_choose_cfqg(cfqd
);
2973 cfqq
= cfq_set_active_queue(cfqd
, new_cfqq
);
2978 static int __cfq_forced_dispatch_cfqq(struct cfq_queue
*cfqq
)
2982 while (cfqq
->next_rq
) {
2983 cfq_dispatch_insert(cfqq
->cfqd
->queue
, cfqq
->next_rq
);
2987 BUG_ON(!list_empty(&cfqq
->fifo
));
2989 /* By default cfqq is not expired if it is empty. Do it explicitly */
2990 __cfq_slice_expired(cfqq
->cfqd
, cfqq
, 0);
2995 * Drain our current requests. Used for barriers and when switching
2996 * io schedulers on-the-fly.
2998 static int cfq_forced_dispatch(struct cfq_data
*cfqd
)
3000 struct cfq_queue
*cfqq
;
3003 /* Expire the timeslice of the current active queue first */
3004 cfq_slice_expired(cfqd
, 0);
3005 while ((cfqq
= cfq_get_next_queue_forced(cfqd
)) != NULL
) {
3006 __cfq_set_active_queue(cfqd
, cfqq
);
3007 dispatched
+= __cfq_forced_dispatch_cfqq(cfqq
);
3010 BUG_ON(cfqd
->busy_queues
);
3012 cfq_log(cfqd
, "forced_dispatch=%d", dispatched
);
3016 static inline bool cfq_slice_used_soon(struct cfq_data
*cfqd
,
3017 struct cfq_queue
*cfqq
)
3019 /* the queue hasn't finished any request, can't estimate */
3020 if (cfq_cfqq_slice_new(cfqq
))
3022 if (time_after(jiffies
+ cfqd
->cfq_slice_idle
* cfqq
->dispatched
,
3029 static bool cfq_may_dispatch(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
3031 unsigned int max_dispatch
;
3034 * Drain async requests before we start sync IO
3036 if (cfq_should_idle(cfqd
, cfqq
) && cfqd
->rq_in_flight
[BLK_RW_ASYNC
])
3040 * If this is an async queue and we have sync IO in flight, let it wait
3042 if (cfqd
->rq_in_flight
[BLK_RW_SYNC
] && !cfq_cfqq_sync(cfqq
))
3045 max_dispatch
= max_t(unsigned int, cfqd
->cfq_quantum
/ 2, 1);
3046 if (cfq_class_idle(cfqq
))
3050 * Does this cfqq already have too much IO in flight?
3052 if (cfqq
->dispatched
>= max_dispatch
) {
3053 bool promote_sync
= false;
3055 * idle queue must always only have a single IO in flight
3057 if (cfq_class_idle(cfqq
))
3061 * If there is only one sync queue
3062 * we can ignore async queue here and give the sync
3063 * queue no dispatch limit. The reason is a sync queue can
3064 * preempt async queue, limiting the sync queue doesn't make
3065 * sense. This is useful for aiostress test.
3067 if (cfq_cfqq_sync(cfqq
) && cfqd
->busy_sync_queues
== 1)
3068 promote_sync
= true;
3071 * We have other queues, don't allow more IO from this one
3073 if (cfqd
->busy_queues
> 1 && cfq_slice_used_soon(cfqd
, cfqq
) &&
3078 * Sole queue user, no limit
3080 if (cfqd
->busy_queues
== 1 || promote_sync
)
3084 * Normally we start throttling cfqq when cfq_quantum/2
3085 * requests have been dispatched. But we can drive
3086 * deeper queue depths at the beginning of slice
3087 * subjected to upper limit of cfq_quantum.
3089 max_dispatch
= cfqd
->cfq_quantum
;
3093 * Async queues must wait a bit before being allowed dispatch.
3094 * We also ramp up the dispatch depth gradually for async IO,
3095 * based on the last sync IO we serviced
3097 if (!cfq_cfqq_sync(cfqq
) && cfqd
->cfq_latency
) {
3098 unsigned long last_sync
= jiffies
- cfqd
->last_delayed_sync
;
3101 depth
= last_sync
/ cfqd
->cfq_slice
[1];
3102 if (!depth
&& !cfqq
->dispatched
)
3104 if (depth
< max_dispatch
)
3105 max_dispatch
= depth
;
3109 * If we're below the current max, allow a dispatch
3111 return cfqq
->dispatched
< max_dispatch
;
3115 * Dispatch a request from cfqq, moving them to the request queue
3118 static bool cfq_dispatch_request(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
3122 BUG_ON(RB_EMPTY_ROOT(&cfqq
->sort_list
));
3124 if (!cfq_may_dispatch(cfqd
, cfqq
))
3128 * follow expired path, else get first next available
3130 rq
= cfq_check_fifo(cfqq
);
3135 * insert request into driver dispatch list
3137 cfq_dispatch_insert(cfqd
->queue
, rq
);
3139 if (!cfqd
->active_cic
) {
3140 struct cfq_io_cq
*cic
= RQ_CIC(rq
);
3142 atomic_long_inc(&cic
->icq
.ioc
->refcount
);
3143 cfqd
->active_cic
= cic
;
3150 * Find the cfqq that we need to service and move a request from that to the
3153 static int cfq_dispatch_requests(struct request_queue
*q
, int force
)
3155 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
3156 struct cfq_queue
*cfqq
;
3158 if (!cfqd
->busy_queues
)
3161 if (unlikely(force
))
3162 return cfq_forced_dispatch(cfqd
);
3164 cfqq
= cfq_select_queue(cfqd
);
3169 * Dispatch a request from this cfqq, if it is allowed
3171 if (!cfq_dispatch_request(cfqd
, cfqq
))
3174 cfqq
->slice_dispatch
++;
3175 cfq_clear_cfqq_must_dispatch(cfqq
);
3178 * expire an async queue immediately if it has used up its slice. idle
3179 * queue always expire after 1 dispatch round.
3181 if (cfqd
->busy_queues
> 1 && ((!cfq_cfqq_sync(cfqq
) &&
3182 cfqq
->slice_dispatch
>= cfq_prio_to_maxrq(cfqd
, cfqq
)) ||
3183 cfq_class_idle(cfqq
))) {
3184 cfqq
->slice_end
= jiffies
+ 1;
3185 cfq_slice_expired(cfqd
, 0);
3188 cfq_log_cfqq(cfqd
, cfqq
, "dispatched a request");
3193 * task holds one reference to the queue, dropped when task exits. each rq
3194 * in-flight on this queue also holds a reference, dropped when rq is freed.
3196 * Each cfq queue took a reference on the parent group. Drop it now.
3197 * queue lock must be held here.
3199 static void cfq_put_queue(struct cfq_queue
*cfqq
)
3201 struct cfq_data
*cfqd
= cfqq
->cfqd
;
3202 struct cfq_group
*cfqg
;
3204 BUG_ON(cfqq
->ref
<= 0);
3210 cfq_log_cfqq(cfqd
, cfqq
, "put_queue");
3211 BUG_ON(rb_first(&cfqq
->sort_list
));
3212 BUG_ON(cfqq
->allocated
[READ
] + cfqq
->allocated
[WRITE
]);
3215 if (unlikely(cfqd
->active_queue
== cfqq
)) {
3216 __cfq_slice_expired(cfqd
, cfqq
, 0);
3217 cfq_schedule_dispatch(cfqd
);
3220 BUG_ON(cfq_cfqq_on_rr(cfqq
));
3221 kmem_cache_free(cfq_pool
, cfqq
);
3225 static void cfq_put_cooperator(struct cfq_queue
*cfqq
)
3227 struct cfq_queue
*__cfqq
, *next
;
3230 * If this queue was scheduled to merge with another queue, be
3231 * sure to drop the reference taken on that queue (and others in
3232 * the merge chain). See cfq_setup_merge and cfq_merge_cfqqs.
3234 __cfqq
= cfqq
->new_cfqq
;
3236 if (__cfqq
== cfqq
) {
3237 WARN(1, "cfqq->new_cfqq loop detected\n");
3240 next
= __cfqq
->new_cfqq
;
3241 cfq_put_queue(__cfqq
);
3246 static void cfq_exit_cfqq(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
3248 if (unlikely(cfqq
== cfqd
->active_queue
)) {
3249 __cfq_slice_expired(cfqd
, cfqq
, 0);
3250 cfq_schedule_dispatch(cfqd
);
3253 cfq_put_cooperator(cfqq
);
3255 cfq_put_queue(cfqq
);
3258 static void cfq_init_icq(struct io_cq
*icq
)
3260 struct cfq_io_cq
*cic
= icq_to_cic(icq
);
3262 cic
->ttime
.last_end_request
= jiffies
;
3265 static void cfq_exit_icq(struct io_cq
*icq
)
3267 struct cfq_io_cq
*cic
= icq_to_cic(icq
);
3268 struct cfq_data
*cfqd
= cic_to_cfqd(cic
);
3270 if (cic
->cfqq
[BLK_RW_ASYNC
]) {
3271 cfq_exit_cfqq(cfqd
, cic
->cfqq
[BLK_RW_ASYNC
]);
3272 cic
->cfqq
[BLK_RW_ASYNC
] = NULL
;
3275 if (cic
->cfqq
[BLK_RW_SYNC
]) {
3276 cfq_exit_cfqq(cfqd
, cic
->cfqq
[BLK_RW_SYNC
]);
3277 cic
->cfqq
[BLK_RW_SYNC
] = NULL
;
3281 static void cfq_init_prio_data(struct cfq_queue
*cfqq
, struct cfq_io_cq
*cic
)
3283 struct task_struct
*tsk
= current
;
3286 if (!cfq_cfqq_prio_changed(cfqq
))
3289 ioprio_class
= IOPRIO_PRIO_CLASS(cic
->ioprio
);
3290 switch (ioprio_class
) {
3292 printk(KERN_ERR
"cfq: bad prio %x\n", ioprio_class
);
3293 case IOPRIO_CLASS_NONE
:
3295 * no prio set, inherit CPU scheduling settings
3297 cfqq
->ioprio
= task_nice_ioprio(tsk
);
3298 cfqq
->ioprio_class
= task_nice_ioclass(tsk
);
3300 case IOPRIO_CLASS_RT
:
3301 cfqq
->ioprio
= IOPRIO_PRIO_DATA(cic
->ioprio
);
3302 cfqq
->ioprio_class
= IOPRIO_CLASS_RT
;
3304 case IOPRIO_CLASS_BE
:
3305 cfqq
->ioprio
= IOPRIO_PRIO_DATA(cic
->ioprio
);
3306 cfqq
->ioprio_class
= IOPRIO_CLASS_BE
;
3308 case IOPRIO_CLASS_IDLE
:
3309 cfqq
->ioprio_class
= IOPRIO_CLASS_IDLE
;
3311 cfq_clear_cfqq_idle_window(cfqq
);
3316 * keep track of original prio settings in case we have to temporarily
3317 * elevate the priority of this queue
3319 cfqq
->org_ioprio
= cfqq
->ioprio
;
3320 cfq_clear_cfqq_prio_changed(cfqq
);
3323 static void check_ioprio_changed(struct cfq_io_cq
*cic
, struct bio
*bio
)
3325 int ioprio
= cic
->icq
.ioc
->ioprio
;
3326 struct cfq_data
*cfqd
= cic_to_cfqd(cic
);
3327 struct cfq_queue
*cfqq
;
3330 * Check whether ioprio has changed. The condition may trigger
3331 * spuriously on a newly created cic but there's no harm.
3333 if (unlikely(!cfqd
) || likely(cic
->ioprio
== ioprio
))
3336 cfqq
= cic
->cfqq
[BLK_RW_ASYNC
];
3338 struct cfq_queue
*new_cfqq
;
3339 new_cfqq
= cfq_get_queue(cfqd
, BLK_RW_ASYNC
, cic
, bio
,
3342 cic
->cfqq
[BLK_RW_ASYNC
] = new_cfqq
;
3343 cfq_put_queue(cfqq
);
3347 cfqq
= cic
->cfqq
[BLK_RW_SYNC
];
3349 cfq_mark_cfqq_prio_changed(cfqq
);
3351 cic
->ioprio
= ioprio
;
3354 static void cfq_init_cfqq(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
3355 pid_t pid
, bool is_sync
)
3357 RB_CLEAR_NODE(&cfqq
->rb_node
);
3358 RB_CLEAR_NODE(&cfqq
->p_node
);
3359 INIT_LIST_HEAD(&cfqq
->fifo
);
3364 cfq_mark_cfqq_prio_changed(cfqq
);
3367 if (!cfq_class_idle(cfqq
))
3368 cfq_mark_cfqq_idle_window(cfqq
);
3369 cfq_mark_cfqq_sync(cfqq
);
3374 #ifdef CONFIG_CFQ_GROUP_IOSCHED
3375 static void check_blkcg_changed(struct cfq_io_cq
*cic
, struct bio
*bio
)
3377 struct cfq_data
*cfqd
= cic_to_cfqd(cic
);
3378 struct cfq_queue
*sync_cfqq
;
3382 id
= bio_blkcg(bio
)->id
;
3386 * Check whether blkcg has changed. The condition may trigger
3387 * spuriously on a newly created cic but there's no harm.
3389 if (unlikely(!cfqd
) || likely(cic
->blkcg_id
== id
))
3392 sync_cfqq
= cic_to_cfqq(cic
, 1);
3395 * Drop reference to sync queue. A new sync queue will be
3396 * assigned in new group upon arrival of a fresh request.
3398 cfq_log_cfqq(cfqd
, sync_cfqq
, "changed cgroup");
3399 cic_set_cfqq(cic
, NULL
, 1);
3400 cfq_put_queue(sync_cfqq
);
3406 static inline void check_blkcg_changed(struct cfq_io_cq
*cic
, struct bio
*bio
) { }
3407 #endif /* CONFIG_CFQ_GROUP_IOSCHED */
3409 static struct cfq_queue
*
3410 cfq_find_alloc_queue(struct cfq_data
*cfqd
, bool is_sync
, struct cfq_io_cq
*cic
,
3411 struct bio
*bio
, gfp_t gfp_mask
)
3413 struct blkcg
*blkcg
;
3414 struct cfq_queue
*cfqq
, *new_cfqq
= NULL
;
3415 struct cfq_group
*cfqg
;
3420 blkcg
= bio_blkcg(bio
);
3421 cfqg
= cfq_lookup_create_cfqg(cfqd
, blkcg
);
3422 cfqq
= cic_to_cfqq(cic
, is_sync
);
3425 * Always try a new alloc if we fell back to the OOM cfqq
3426 * originally, since it should just be a temporary situation.
3428 if (!cfqq
|| cfqq
== &cfqd
->oom_cfqq
) {
3433 } else if (gfp_mask
& __GFP_WAIT
) {
3435 spin_unlock_irq(cfqd
->queue
->queue_lock
);
3436 new_cfqq
= kmem_cache_alloc_node(cfq_pool
,
3437 gfp_mask
| __GFP_ZERO
,
3439 spin_lock_irq(cfqd
->queue
->queue_lock
);
3443 cfqq
= kmem_cache_alloc_node(cfq_pool
,
3444 gfp_mask
| __GFP_ZERO
,
3449 cfq_init_cfqq(cfqd
, cfqq
, current
->pid
, is_sync
);
3450 cfq_init_prio_data(cfqq
, cic
);
3451 cfq_link_cfqq_cfqg(cfqq
, cfqg
);
3452 cfq_log_cfqq(cfqd
, cfqq
, "alloced");
3454 cfqq
= &cfqd
->oom_cfqq
;
3458 kmem_cache_free(cfq_pool
, new_cfqq
);
3464 static struct cfq_queue
**
3465 cfq_async_queue_prio(struct cfq_data
*cfqd
, int ioprio_class
, int ioprio
)
3467 switch (ioprio_class
) {
3468 case IOPRIO_CLASS_RT
:
3469 return &cfqd
->async_cfqq
[0][ioprio
];
3470 case IOPRIO_CLASS_NONE
:
3471 ioprio
= IOPRIO_NORM
;
3473 case IOPRIO_CLASS_BE
:
3474 return &cfqd
->async_cfqq
[1][ioprio
];
3475 case IOPRIO_CLASS_IDLE
:
3476 return &cfqd
->async_idle_cfqq
;
3482 static struct cfq_queue
*
3483 cfq_get_queue(struct cfq_data
*cfqd
, bool is_sync
, struct cfq_io_cq
*cic
,
3484 struct bio
*bio
, gfp_t gfp_mask
)
3486 const int ioprio_class
= IOPRIO_PRIO_CLASS(cic
->ioprio
);
3487 const int ioprio
= IOPRIO_PRIO_DATA(cic
->ioprio
);
3488 struct cfq_queue
**async_cfqq
= NULL
;
3489 struct cfq_queue
*cfqq
= NULL
;
3492 async_cfqq
= cfq_async_queue_prio(cfqd
, ioprio_class
, ioprio
);
3497 cfqq
= cfq_find_alloc_queue(cfqd
, is_sync
, cic
, bio
, gfp_mask
);
3500 * pin the queue now that it's allocated, scheduler exit will prune it
3502 if (!is_sync
&& !(*async_cfqq
)) {
3512 __cfq_update_io_thinktime(struct cfq_ttime
*ttime
, unsigned long slice_idle
)
3514 unsigned long elapsed
= jiffies
- ttime
->last_end_request
;
3515 elapsed
= min(elapsed
, 2UL * slice_idle
);
3517 ttime
->ttime_samples
= (7*ttime
->ttime_samples
+ 256) / 8;
3518 ttime
->ttime_total
= (7*ttime
->ttime_total
+ 256*elapsed
) / 8;
3519 ttime
->ttime_mean
= (ttime
->ttime_total
+ 128) / ttime
->ttime_samples
;
3523 cfq_update_io_thinktime(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
3524 struct cfq_io_cq
*cic
)
3526 if (cfq_cfqq_sync(cfqq
)) {
3527 __cfq_update_io_thinktime(&cic
->ttime
, cfqd
->cfq_slice_idle
);
3528 __cfq_update_io_thinktime(&cfqq
->service_tree
->ttime
,
3529 cfqd
->cfq_slice_idle
);
3531 #ifdef CONFIG_CFQ_GROUP_IOSCHED
3532 __cfq_update_io_thinktime(&cfqq
->cfqg
->ttime
, cfqd
->cfq_group_idle
);
3537 cfq_update_io_seektime(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
3541 sector_t n_sec
= blk_rq_sectors(rq
);
3542 if (cfqq
->last_request_pos
) {
3543 if (cfqq
->last_request_pos
< blk_rq_pos(rq
))
3544 sdist
= blk_rq_pos(rq
) - cfqq
->last_request_pos
;
3546 sdist
= cfqq
->last_request_pos
- blk_rq_pos(rq
);
3549 cfqq
->seek_history
<<= 1;
3550 if (blk_queue_nonrot(cfqd
->queue
))
3551 cfqq
->seek_history
|= (n_sec
< CFQQ_SECT_THR_NONROT
);
3553 cfqq
->seek_history
|= (sdist
> CFQQ_SEEK_THR
);
3557 * Disable idle window if the process thinks too long or seeks so much that
3561 cfq_update_idle_window(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
3562 struct cfq_io_cq
*cic
)
3564 int old_idle
, enable_idle
;
3567 * Don't idle for async or idle io prio class
3569 if (!cfq_cfqq_sync(cfqq
) || cfq_class_idle(cfqq
))
3572 enable_idle
= old_idle
= cfq_cfqq_idle_window(cfqq
);
3574 if (cfqq
->queued
[0] + cfqq
->queued
[1] >= 4)
3575 cfq_mark_cfqq_deep(cfqq
);
3577 if (cfqq
->next_rq
&& (cfqq
->next_rq
->cmd_flags
& REQ_NOIDLE
))
3579 else if (!atomic_read(&cic
->icq
.ioc
->active_ref
) ||
3580 !cfqd
->cfq_slice_idle
||
3581 (!cfq_cfqq_deep(cfqq
) && CFQQ_SEEKY(cfqq
)))
3583 else if (sample_valid(cic
->ttime
.ttime_samples
)) {
3584 if (cic
->ttime
.ttime_mean
> cfqd
->cfq_slice_idle
)
3590 if (old_idle
!= enable_idle
) {
3591 cfq_log_cfqq(cfqd
, cfqq
, "idle=%d", enable_idle
);
3593 cfq_mark_cfqq_idle_window(cfqq
);
3595 cfq_clear_cfqq_idle_window(cfqq
);
3600 * Check if new_cfqq should preempt the currently active queue. Return 0 for
3601 * no or if we aren't sure, a 1 will cause a preempt.
3604 cfq_should_preempt(struct cfq_data
*cfqd
, struct cfq_queue
*new_cfqq
,
3607 struct cfq_queue
*cfqq
;
3609 cfqq
= cfqd
->active_queue
;
3613 if (cfq_class_idle(new_cfqq
))
3616 if (cfq_class_idle(cfqq
))
3620 * Don't allow a non-RT request to preempt an ongoing RT cfqq timeslice.
3622 if (cfq_class_rt(cfqq
) && !cfq_class_rt(new_cfqq
))
3626 * if the new request is sync, but the currently running queue is
3627 * not, let the sync request have priority.
3629 if (rq_is_sync(rq
) && !cfq_cfqq_sync(cfqq
))
3632 if (new_cfqq
->cfqg
!= cfqq
->cfqg
)
3635 if (cfq_slice_used(cfqq
))
3638 /* Allow preemption only if we are idling on sync-noidle tree */
3639 if (cfqd
->serving_wl_type
== SYNC_NOIDLE_WORKLOAD
&&
3640 cfqq_type(new_cfqq
) == SYNC_NOIDLE_WORKLOAD
&&
3641 new_cfqq
->service_tree
->count
== 2 &&
3642 RB_EMPTY_ROOT(&cfqq
->sort_list
))
3646 * So both queues are sync. Let the new request get disk time if
3647 * it's a metadata request and the current queue is doing regular IO.
3649 if ((rq
->cmd_flags
& REQ_PRIO
) && !cfqq
->prio_pending
)
3653 * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice.
3655 if (cfq_class_rt(new_cfqq
) && !cfq_class_rt(cfqq
))
3658 /* An idle queue should not be idle now for some reason */
3659 if (RB_EMPTY_ROOT(&cfqq
->sort_list
) && !cfq_should_idle(cfqd
, cfqq
))
3662 if (!cfqd
->active_cic
|| !cfq_cfqq_wait_request(cfqq
))
3666 * if this request is as-good as one we would expect from the
3667 * current cfqq, let it preempt
3669 if (cfq_rq_close(cfqd
, cfqq
, rq
))
3676 * cfqq preempts the active queue. if we allowed preempt with no slice left,
3677 * let it have half of its nominal slice.
3679 static void cfq_preempt_queue(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
3681 enum wl_type_t old_type
= cfqq_type(cfqd
->active_queue
);
3683 cfq_log_cfqq(cfqd
, cfqq
, "preempt");
3684 cfq_slice_expired(cfqd
, 1);
3687 * workload type is changed, don't save slice, otherwise preempt
3690 if (old_type
!= cfqq_type(cfqq
))
3691 cfqq
->cfqg
->saved_wl_slice
= 0;
3694 * Put the new queue at the front of the of the current list,
3695 * so we know that it will be selected next.
3697 BUG_ON(!cfq_cfqq_on_rr(cfqq
));
3699 cfq_service_tree_add(cfqd
, cfqq
, 1);
3701 cfqq
->slice_end
= 0;
3702 cfq_mark_cfqq_slice_new(cfqq
);
3706 * Called when a new fs request (rq) is added (to cfqq). Check if there's
3707 * something we should do about it
3710 cfq_rq_enqueued(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
3713 struct cfq_io_cq
*cic
= RQ_CIC(rq
);
3716 if (rq
->cmd_flags
& REQ_PRIO
)
3717 cfqq
->prio_pending
++;
3719 cfq_update_io_thinktime(cfqd
, cfqq
, cic
);
3720 cfq_update_io_seektime(cfqd
, cfqq
, rq
);
3721 cfq_update_idle_window(cfqd
, cfqq
, cic
);
3723 cfqq
->last_request_pos
= blk_rq_pos(rq
) + blk_rq_sectors(rq
);
3725 if (cfqq
== cfqd
->active_queue
) {
3727 * Remember that we saw a request from this process, but
3728 * don't start queuing just yet. Otherwise we risk seeing lots
3729 * of tiny requests, because we disrupt the normal plugging
3730 * and merging. If the request is already larger than a single
3731 * page, let it rip immediately. For that case we assume that
3732 * merging is already done. Ditto for a busy system that
3733 * has other work pending, don't risk delaying until the
3734 * idle timer unplug to continue working.
3736 if (cfq_cfqq_wait_request(cfqq
)) {
3737 if (blk_rq_bytes(rq
) > PAGE_CACHE_SIZE
||
3738 cfqd
->busy_queues
> 1) {
3739 cfq_del_timer(cfqd
, cfqq
);
3740 cfq_clear_cfqq_wait_request(cfqq
);
3741 __blk_run_queue(cfqd
->queue
);
3743 cfqg_stats_update_idle_time(cfqq
->cfqg
);
3744 cfq_mark_cfqq_must_dispatch(cfqq
);
3747 } else if (cfq_should_preempt(cfqd
, cfqq
, rq
)) {
3749 * not the active queue - expire current slice if it is
3750 * idle and has expired it's mean thinktime or this new queue
3751 * has some old slice time left and is of higher priority or
3752 * this new queue is RT and the current one is BE
3754 cfq_preempt_queue(cfqd
, cfqq
);
3755 __blk_run_queue(cfqd
->queue
);
3759 static void cfq_insert_request(struct request_queue
*q
, struct request
*rq
)
3761 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
3762 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
3764 cfq_log_cfqq(cfqd
, cfqq
, "insert_request");
3765 cfq_init_prio_data(cfqq
, RQ_CIC(rq
));
3767 rq_set_fifo_time(rq
, jiffies
+ cfqd
->cfq_fifo_expire
[rq_is_sync(rq
)]);
3768 list_add_tail(&rq
->queuelist
, &cfqq
->fifo
);
3770 cfqg_stats_update_io_add(RQ_CFQG(rq
), cfqd
->serving_group
,
3772 cfq_rq_enqueued(cfqd
, cfqq
, rq
);
3776 * Update hw_tag based on peak queue depth over 50 samples under
3779 static void cfq_update_hw_tag(struct cfq_data
*cfqd
)
3781 struct cfq_queue
*cfqq
= cfqd
->active_queue
;
3783 if (cfqd
->rq_in_driver
> cfqd
->hw_tag_est_depth
)
3784 cfqd
->hw_tag_est_depth
= cfqd
->rq_in_driver
;
3786 if (cfqd
->hw_tag
== 1)
3789 if (cfqd
->rq_queued
<= CFQ_HW_QUEUE_MIN
&&
3790 cfqd
->rq_in_driver
<= CFQ_HW_QUEUE_MIN
)
3794 * If active queue hasn't enough requests and can idle, cfq might not
3795 * dispatch sufficient requests to hardware. Don't zero hw_tag in this
3798 if (cfqq
&& cfq_cfqq_idle_window(cfqq
) &&
3799 cfqq
->dispatched
+ cfqq
->queued
[0] + cfqq
->queued
[1] <
3800 CFQ_HW_QUEUE_MIN
&& cfqd
->rq_in_driver
< CFQ_HW_QUEUE_MIN
)
3803 if (cfqd
->hw_tag_samples
++ < 50)
3806 if (cfqd
->hw_tag_est_depth
>= CFQ_HW_QUEUE_MIN
)
3812 static bool cfq_should_wait_busy(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
3814 struct cfq_io_cq
*cic
= cfqd
->active_cic
;
3816 /* If the queue already has requests, don't wait */
3817 if (!RB_EMPTY_ROOT(&cfqq
->sort_list
))
3820 /* If there are other queues in the group, don't wait */
3821 if (cfqq
->cfqg
->nr_cfqq
> 1)
3824 /* the only queue in the group, but think time is big */
3825 if (cfq_io_thinktime_big(cfqd
, &cfqq
->cfqg
->ttime
, true))
3828 if (cfq_slice_used(cfqq
))
3831 /* if slice left is less than think time, wait busy */
3832 if (cic
&& sample_valid(cic
->ttime
.ttime_samples
)
3833 && (cfqq
->slice_end
- jiffies
< cic
->ttime
.ttime_mean
))
3837 * If think times is less than a jiffy than ttime_mean=0 and above
3838 * will not be true. It might happen that slice has not expired yet
3839 * but will expire soon (4-5 ns) during select_queue(). To cover the
3840 * case where think time is less than a jiffy, mark the queue wait
3841 * busy if only 1 jiffy is left in the slice.
3843 if (cfqq
->slice_end
- jiffies
== 1)
3849 static void cfq_completed_request(struct request_queue
*q
, struct request
*rq
)
3851 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
3852 struct cfq_data
*cfqd
= cfqq
->cfqd
;
3853 const int sync
= rq_is_sync(rq
);
3857 cfq_log_cfqq(cfqd
, cfqq
, "complete rqnoidle %d",
3858 !!(rq
->cmd_flags
& REQ_NOIDLE
));
3860 cfq_update_hw_tag(cfqd
);
3862 WARN_ON(!cfqd
->rq_in_driver
);
3863 WARN_ON(!cfqq
->dispatched
);
3864 cfqd
->rq_in_driver
--;
3866 (RQ_CFQG(rq
))->dispatched
--;
3867 cfqg_stats_update_completion(cfqq
->cfqg
, rq_start_time_ns(rq
),
3868 rq_io_start_time_ns(rq
), rq
->cmd_flags
);
3870 cfqd
->rq_in_flight
[cfq_cfqq_sync(cfqq
)]--;
3873 struct cfq_rb_root
*st
;
3875 RQ_CIC(rq
)->ttime
.last_end_request
= now
;
3877 if (cfq_cfqq_on_rr(cfqq
))
3878 st
= cfqq
->service_tree
;
3880 st
= st_for(cfqq
->cfqg
, cfqq_class(cfqq
),
3883 st
->ttime
.last_end_request
= now
;
3884 if (!time_after(rq
->start_time
+ cfqd
->cfq_fifo_expire
[1], now
))
3885 cfqd
->last_delayed_sync
= now
;
3888 #ifdef CONFIG_CFQ_GROUP_IOSCHED
3889 cfqq
->cfqg
->ttime
.last_end_request
= now
;
3893 * If this is the active queue, check if it needs to be expired,
3894 * or if we want to idle in case it has no pending requests.
3896 if (cfqd
->active_queue
== cfqq
) {
3897 const bool cfqq_empty
= RB_EMPTY_ROOT(&cfqq
->sort_list
);
3899 if (cfq_cfqq_slice_new(cfqq
)) {
3900 cfq_set_prio_slice(cfqd
, cfqq
);
3901 cfq_clear_cfqq_slice_new(cfqq
);
3905 * Should we wait for next request to come in before we expire
3908 if (cfq_should_wait_busy(cfqd
, cfqq
)) {
3909 unsigned long extend_sl
= cfqd
->cfq_slice_idle
;
3910 if (!cfqd
->cfq_slice_idle
)
3911 extend_sl
= cfqd
->cfq_group_idle
;
3912 cfqq
->slice_end
= jiffies
+ extend_sl
;
3913 cfq_mark_cfqq_wait_busy(cfqq
);
3914 cfq_log_cfqq(cfqd
, cfqq
, "will busy wait");
3918 * Idling is not enabled on:
3920 * - idle-priority queues
3922 * - queues with still some requests queued
3923 * - when there is a close cooperator
3925 if (cfq_slice_used(cfqq
) || cfq_class_idle(cfqq
))
3926 cfq_slice_expired(cfqd
, 1);
3927 else if (sync
&& cfqq_empty
&&
3928 !cfq_close_cooperator(cfqd
, cfqq
)) {
3929 cfq_arm_slice_timer(cfqd
);
3933 if (!cfqd
->rq_in_driver
)
3934 cfq_schedule_dispatch(cfqd
);
3937 static inline int __cfq_may_queue(struct cfq_queue
*cfqq
)
3939 if (cfq_cfqq_wait_request(cfqq
) && !cfq_cfqq_must_alloc_slice(cfqq
)) {
3940 cfq_mark_cfqq_must_alloc_slice(cfqq
);
3941 return ELV_MQUEUE_MUST
;
3944 return ELV_MQUEUE_MAY
;
3947 static int cfq_may_queue(struct request_queue
*q
, int rw
)
3949 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
3950 struct task_struct
*tsk
= current
;
3951 struct cfq_io_cq
*cic
;
3952 struct cfq_queue
*cfqq
;
3955 * don't force setup of a queue from here, as a call to may_queue
3956 * does not necessarily imply that a request actually will be queued.
3957 * so just lookup a possibly existing queue, or return 'may queue'
3960 cic
= cfq_cic_lookup(cfqd
, tsk
->io_context
);
3962 return ELV_MQUEUE_MAY
;
3964 cfqq
= cic_to_cfqq(cic
, rw_is_sync(rw
));
3966 cfq_init_prio_data(cfqq
, cic
);
3968 return __cfq_may_queue(cfqq
);
3971 return ELV_MQUEUE_MAY
;
3975 * queue lock held here
3977 static void cfq_put_request(struct request
*rq
)
3979 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
3982 const int rw
= rq_data_dir(rq
);
3984 BUG_ON(!cfqq
->allocated
[rw
]);
3985 cfqq
->allocated
[rw
]--;
3987 /* Put down rq reference on cfqg */
3988 cfqg_put(RQ_CFQG(rq
));
3989 rq
->elv
.priv
[0] = NULL
;
3990 rq
->elv
.priv
[1] = NULL
;
3992 cfq_put_queue(cfqq
);
3996 static struct cfq_queue
*
3997 cfq_merge_cfqqs(struct cfq_data
*cfqd
, struct cfq_io_cq
*cic
,
3998 struct cfq_queue
*cfqq
)
4000 cfq_log_cfqq(cfqd
, cfqq
, "merging with queue %p", cfqq
->new_cfqq
);
4001 cic_set_cfqq(cic
, cfqq
->new_cfqq
, 1);
4002 cfq_mark_cfqq_coop(cfqq
->new_cfqq
);
4003 cfq_put_queue(cfqq
);
4004 return cic_to_cfqq(cic
, 1);
4008 * Returns NULL if a new cfqq should be allocated, or the old cfqq if this
4009 * was the last process referring to said cfqq.
4011 static struct cfq_queue
*
4012 split_cfqq(struct cfq_io_cq
*cic
, struct cfq_queue
*cfqq
)
4014 if (cfqq_process_refs(cfqq
) == 1) {
4015 cfqq
->pid
= current
->pid
;
4016 cfq_clear_cfqq_coop(cfqq
);
4017 cfq_clear_cfqq_split_coop(cfqq
);
4021 cic_set_cfqq(cic
, NULL
, 1);
4023 cfq_put_cooperator(cfqq
);
4025 cfq_put_queue(cfqq
);
4029 * Allocate cfq data structures associated with this request.
4032 cfq_set_request(struct request_queue
*q
, struct request
*rq
, struct bio
*bio
,
4035 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
4036 struct cfq_io_cq
*cic
= icq_to_cic(rq
->elv
.icq
);
4037 const int rw
= rq_data_dir(rq
);
4038 const bool is_sync
= rq_is_sync(rq
);
4039 struct cfq_queue
*cfqq
;
4041 might_sleep_if(gfp_mask
& __GFP_WAIT
);
4043 spin_lock_irq(q
->queue_lock
);
4045 check_ioprio_changed(cic
, bio
);
4046 check_blkcg_changed(cic
, bio
);
4048 cfqq
= cic_to_cfqq(cic
, is_sync
);
4049 if (!cfqq
|| cfqq
== &cfqd
->oom_cfqq
) {
4050 cfqq
= cfq_get_queue(cfqd
, is_sync
, cic
, bio
, gfp_mask
);
4051 cic_set_cfqq(cic
, cfqq
, is_sync
);
4054 * If the queue was seeky for too long, break it apart.
4056 if (cfq_cfqq_coop(cfqq
) && cfq_cfqq_split_coop(cfqq
)) {
4057 cfq_log_cfqq(cfqd
, cfqq
, "breaking apart cfqq");
4058 cfqq
= split_cfqq(cic
, cfqq
);
4064 * Check to see if this queue is scheduled to merge with
4065 * another, closely cooperating queue. The merging of
4066 * queues happens here as it must be done in process context.
4067 * The reference on new_cfqq was taken in merge_cfqqs.
4070 cfqq
= cfq_merge_cfqqs(cfqd
, cic
, cfqq
);
4073 cfqq
->allocated
[rw
]++;
4076 cfqg_get(cfqq
->cfqg
);
4077 rq
->elv
.priv
[0] = cfqq
;
4078 rq
->elv
.priv
[1] = cfqq
->cfqg
;
4079 spin_unlock_irq(q
->queue_lock
);
4083 static void cfq_kick_queue(struct work_struct
*work
)
4085 struct cfq_data
*cfqd
=
4086 container_of(work
, struct cfq_data
, unplug_work
);
4087 struct request_queue
*q
= cfqd
->queue
;
4089 spin_lock_irq(q
->queue_lock
);
4090 __blk_run_queue(cfqd
->queue
);
4091 spin_unlock_irq(q
->queue_lock
);
4095 * Timer running if the active_queue is currently idling inside its time slice
4097 static void cfq_idle_slice_timer(unsigned long data
)
4099 struct cfq_data
*cfqd
= (struct cfq_data
*) data
;
4100 struct cfq_queue
*cfqq
;
4101 unsigned long flags
;
4104 cfq_log(cfqd
, "idle timer fired");
4106 spin_lock_irqsave(cfqd
->queue
->queue_lock
, flags
);
4108 cfqq
= cfqd
->active_queue
;
4113 * We saw a request before the queue expired, let it through
4115 if (cfq_cfqq_must_dispatch(cfqq
))
4121 if (cfq_slice_used(cfqq
))
4125 * only expire and reinvoke request handler, if there are
4126 * other queues with pending requests
4128 if (!cfqd
->busy_queues
)
4132 * not expired and it has a request pending, let it dispatch
4134 if (!RB_EMPTY_ROOT(&cfqq
->sort_list
))
4138 * Queue depth flag is reset only when the idle didn't succeed
4140 cfq_clear_cfqq_deep(cfqq
);
4143 cfq_slice_expired(cfqd
, timed_out
);
4145 cfq_schedule_dispatch(cfqd
);
4147 spin_unlock_irqrestore(cfqd
->queue
->queue_lock
, flags
);
4150 static void cfq_shutdown_timer_wq(struct cfq_data
*cfqd
)
4152 del_timer_sync(&cfqd
->idle_slice_timer
);
4153 cancel_work_sync(&cfqd
->unplug_work
);
4156 static void cfq_put_async_queues(struct cfq_data
*cfqd
)
4160 for (i
= 0; i
< IOPRIO_BE_NR
; i
++) {
4161 if (cfqd
->async_cfqq
[0][i
])
4162 cfq_put_queue(cfqd
->async_cfqq
[0][i
]);
4163 if (cfqd
->async_cfqq
[1][i
])
4164 cfq_put_queue(cfqd
->async_cfqq
[1][i
]);
4167 if (cfqd
->async_idle_cfqq
)
4168 cfq_put_queue(cfqd
->async_idle_cfqq
);
4171 static void cfq_exit_queue(struct elevator_queue
*e
)
4173 struct cfq_data
*cfqd
= e
->elevator_data
;
4174 struct request_queue
*q
= cfqd
->queue
;
4176 cfq_shutdown_timer_wq(cfqd
);
4178 spin_lock_irq(q
->queue_lock
);
4180 if (cfqd
->active_queue
)
4181 __cfq_slice_expired(cfqd
, cfqd
->active_queue
, 0);
4183 cfq_put_async_queues(cfqd
);
4185 spin_unlock_irq(q
->queue_lock
);
4187 cfq_shutdown_timer_wq(cfqd
);
4189 #ifdef CONFIG_CFQ_GROUP_IOSCHED
4190 blkcg_deactivate_policy(q
, &blkcg_policy_cfq
);
4192 kfree(cfqd
->root_group
);
4197 static int cfq_init_queue(struct request_queue
*q
)
4199 struct cfq_data
*cfqd
;
4200 struct blkcg_gq
*blkg __maybe_unused
;
4203 cfqd
= kmalloc_node(sizeof(*cfqd
), GFP_KERNEL
| __GFP_ZERO
, q
->node
);
4208 q
->elevator
->elevator_data
= cfqd
;
4210 /* Init root service tree */
4211 cfqd
->grp_service_tree
= CFQ_RB_ROOT
;
4213 /* Init root group and prefer root group over other groups by default */
4214 #ifdef CONFIG_CFQ_GROUP_IOSCHED
4215 ret
= blkcg_activate_policy(q
, &blkcg_policy_cfq
);
4219 cfqd
->root_group
= blkg_to_cfqg(q
->root_blkg
);
4222 cfqd
->root_group
= kzalloc_node(sizeof(*cfqd
->root_group
),
4223 GFP_KERNEL
, cfqd
->queue
->node
);
4224 if (!cfqd
->root_group
)
4227 cfq_init_cfqg_base(cfqd
->root_group
);
4229 cfqd
->root_group
->weight
= 2 * CFQ_WEIGHT_DEFAULT
;
4230 cfqd
->root_group
->leaf_weight
= 2 * CFQ_WEIGHT_DEFAULT
;
4233 * Not strictly needed (since RB_ROOT just clears the node and we
4234 * zeroed cfqd on alloc), but better be safe in case someone decides
4235 * to add magic to the rb code
4237 for (i
= 0; i
< CFQ_PRIO_LISTS
; i
++)
4238 cfqd
->prio_trees
[i
] = RB_ROOT
;
4241 * Our fallback cfqq if cfq_find_alloc_queue() runs into OOM issues.
4242 * Grab a permanent reference to it, so that the normal code flow
4243 * will not attempt to free it. oom_cfqq is linked to root_group
4244 * but shouldn't hold a reference as it'll never be unlinked. Lose
4245 * the reference from linking right away.
4247 cfq_init_cfqq(cfqd
, &cfqd
->oom_cfqq
, 1, 0);
4248 cfqd
->oom_cfqq
.ref
++;
4250 spin_lock_irq(q
->queue_lock
);
4251 cfq_link_cfqq_cfqg(&cfqd
->oom_cfqq
, cfqd
->root_group
);
4252 cfqg_put(cfqd
->root_group
);
4253 spin_unlock_irq(q
->queue_lock
);
4255 init_timer(&cfqd
->idle_slice_timer
);
4256 cfqd
->idle_slice_timer
.function
= cfq_idle_slice_timer
;
4257 cfqd
->idle_slice_timer
.data
= (unsigned long) cfqd
;
4259 INIT_WORK(&cfqd
->unplug_work
, cfq_kick_queue
);
4261 cfqd
->cfq_quantum
= cfq_quantum
;
4262 cfqd
->cfq_fifo_expire
[0] = cfq_fifo_expire
[0];
4263 cfqd
->cfq_fifo_expire
[1] = cfq_fifo_expire
[1];
4264 cfqd
->cfq_back_max
= cfq_back_max
;
4265 cfqd
->cfq_back_penalty
= cfq_back_penalty
;
4266 cfqd
->cfq_slice
[0] = cfq_slice_async
;
4267 cfqd
->cfq_slice
[1] = cfq_slice_sync
;
4268 cfqd
->cfq_target_latency
= cfq_target_latency
;
4269 cfqd
->cfq_slice_async_rq
= cfq_slice_async_rq
;
4270 cfqd
->cfq_slice_idle
= cfq_slice_idle
;
4271 cfqd
->cfq_group_idle
= cfq_group_idle
;
4272 cfqd
->cfq_latency
= 1;
4275 * we optimistically start assuming sync ops weren't delayed in last
4276 * second, in order to have larger depth for async operations.
4278 cfqd
->last_delayed_sync
= jiffies
- HZ
;
4287 * sysfs parts below -->
4290 cfq_var_show(unsigned int var
, char *page
)
4292 return sprintf(page
, "%d\n", var
);
4296 cfq_var_store(unsigned int *var
, const char *page
, size_t count
)
4298 char *p
= (char *) page
;
4300 *var
= simple_strtoul(p
, &p
, 10);
4304 #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \
4305 static ssize_t __FUNC(struct elevator_queue *e, char *page) \
4307 struct cfq_data *cfqd = e->elevator_data; \
4308 unsigned int __data = __VAR; \
4310 __data = jiffies_to_msecs(__data); \
4311 return cfq_var_show(__data, (page)); \
4313 SHOW_FUNCTION(cfq_quantum_show
, cfqd
->cfq_quantum
, 0);
4314 SHOW_FUNCTION(cfq_fifo_expire_sync_show
, cfqd
->cfq_fifo_expire
[1], 1);
4315 SHOW_FUNCTION(cfq_fifo_expire_async_show
, cfqd
->cfq_fifo_expire
[0], 1);
4316 SHOW_FUNCTION(cfq_back_seek_max_show
, cfqd
->cfq_back_max
, 0);
4317 SHOW_FUNCTION(cfq_back_seek_penalty_show
, cfqd
->cfq_back_penalty
, 0);
4318 SHOW_FUNCTION(cfq_slice_idle_show
, cfqd
->cfq_slice_idle
, 1);
4319 SHOW_FUNCTION(cfq_group_idle_show
, cfqd
->cfq_group_idle
, 1);
4320 SHOW_FUNCTION(cfq_slice_sync_show
, cfqd
->cfq_slice
[1], 1);
4321 SHOW_FUNCTION(cfq_slice_async_show
, cfqd
->cfq_slice
[0], 1);
4322 SHOW_FUNCTION(cfq_slice_async_rq_show
, cfqd
->cfq_slice_async_rq
, 0);
4323 SHOW_FUNCTION(cfq_low_latency_show
, cfqd
->cfq_latency
, 0);
4324 SHOW_FUNCTION(cfq_target_latency_show
, cfqd
->cfq_target_latency
, 1);
4325 #undef SHOW_FUNCTION
4327 #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \
4328 static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \
4330 struct cfq_data *cfqd = e->elevator_data; \
4331 unsigned int __data; \
4332 int ret = cfq_var_store(&__data, (page), count); \
4333 if (__data < (MIN)) \
4335 else if (__data > (MAX)) \
4338 *(__PTR) = msecs_to_jiffies(__data); \
4340 *(__PTR) = __data; \
4343 STORE_FUNCTION(cfq_quantum_store
, &cfqd
->cfq_quantum
, 1, UINT_MAX
, 0);
4344 STORE_FUNCTION(cfq_fifo_expire_sync_store
, &cfqd
->cfq_fifo_expire
[1], 1,
4346 STORE_FUNCTION(cfq_fifo_expire_async_store
, &cfqd
->cfq_fifo_expire
[0], 1,
4348 STORE_FUNCTION(cfq_back_seek_max_store
, &cfqd
->cfq_back_max
, 0, UINT_MAX
, 0);
4349 STORE_FUNCTION(cfq_back_seek_penalty_store
, &cfqd
->cfq_back_penalty
, 1,
4351 STORE_FUNCTION(cfq_slice_idle_store
, &cfqd
->cfq_slice_idle
, 0, UINT_MAX
, 1);
4352 STORE_FUNCTION(cfq_group_idle_store
, &cfqd
->cfq_group_idle
, 0, UINT_MAX
, 1);
4353 STORE_FUNCTION(cfq_slice_sync_store
, &cfqd
->cfq_slice
[1], 1, UINT_MAX
, 1);
4354 STORE_FUNCTION(cfq_slice_async_store
, &cfqd
->cfq_slice
[0], 1, UINT_MAX
, 1);
4355 STORE_FUNCTION(cfq_slice_async_rq_store
, &cfqd
->cfq_slice_async_rq
, 1,
4357 STORE_FUNCTION(cfq_low_latency_store
, &cfqd
->cfq_latency
, 0, 1, 0);
4358 STORE_FUNCTION(cfq_target_latency_store
, &cfqd
->cfq_target_latency
, 1, UINT_MAX
, 1);
4359 #undef STORE_FUNCTION
4361 #define CFQ_ATTR(name) \
4362 __ATTR(name, S_IRUGO|S_IWUSR, cfq_##name##_show, cfq_##name##_store)
4364 static struct elv_fs_entry cfq_attrs
[] = {
4366 CFQ_ATTR(fifo_expire_sync
),
4367 CFQ_ATTR(fifo_expire_async
),
4368 CFQ_ATTR(back_seek_max
),
4369 CFQ_ATTR(back_seek_penalty
),
4370 CFQ_ATTR(slice_sync
),
4371 CFQ_ATTR(slice_async
),
4372 CFQ_ATTR(slice_async_rq
),
4373 CFQ_ATTR(slice_idle
),
4374 CFQ_ATTR(group_idle
),
4375 CFQ_ATTR(low_latency
),
4376 CFQ_ATTR(target_latency
),
4380 static struct elevator_type iosched_cfq
= {
4382 .elevator_merge_fn
= cfq_merge
,
4383 .elevator_merged_fn
= cfq_merged_request
,
4384 .elevator_merge_req_fn
= cfq_merged_requests
,
4385 .elevator_allow_merge_fn
= cfq_allow_merge
,
4386 .elevator_bio_merged_fn
= cfq_bio_merged
,
4387 .elevator_dispatch_fn
= cfq_dispatch_requests
,
4388 .elevator_add_req_fn
= cfq_insert_request
,
4389 .elevator_activate_req_fn
= cfq_activate_request
,
4390 .elevator_deactivate_req_fn
= cfq_deactivate_request
,
4391 .elevator_completed_req_fn
= cfq_completed_request
,
4392 .elevator_former_req_fn
= elv_rb_former_request
,
4393 .elevator_latter_req_fn
= elv_rb_latter_request
,
4394 .elevator_init_icq_fn
= cfq_init_icq
,
4395 .elevator_exit_icq_fn
= cfq_exit_icq
,
4396 .elevator_set_req_fn
= cfq_set_request
,
4397 .elevator_put_req_fn
= cfq_put_request
,
4398 .elevator_may_queue_fn
= cfq_may_queue
,
4399 .elevator_init_fn
= cfq_init_queue
,
4400 .elevator_exit_fn
= cfq_exit_queue
,
4402 .icq_size
= sizeof(struct cfq_io_cq
),
4403 .icq_align
= __alignof__(struct cfq_io_cq
),
4404 .elevator_attrs
= cfq_attrs
,
4405 .elevator_name
= "cfq",
4406 .elevator_owner
= THIS_MODULE
,
4409 #ifdef CONFIG_CFQ_GROUP_IOSCHED
4410 static struct blkcg_policy blkcg_policy_cfq
= {
4411 .pd_size
= sizeof(struct cfq_group
),
4412 .cftypes
= cfq_blkcg_files
,
4414 .pd_init_fn
= cfq_pd_init
,
4415 .pd_reset_stats_fn
= cfq_pd_reset_stats
,
4419 static int __init
cfq_init(void)
4424 * could be 0 on HZ < 1000 setups
4426 if (!cfq_slice_async
)
4427 cfq_slice_async
= 1;
4428 if (!cfq_slice_idle
)
4431 #ifdef CONFIG_CFQ_GROUP_IOSCHED
4432 if (!cfq_group_idle
)
4435 ret
= blkcg_policy_register(&blkcg_policy_cfq
);
4443 cfq_pool
= KMEM_CACHE(cfq_queue
, 0);
4447 ret
= elv_register(&iosched_cfq
);
4454 kmem_cache_destroy(cfq_pool
);
4456 #ifdef CONFIG_CFQ_GROUP_IOSCHED
4457 blkcg_policy_unregister(&blkcg_policy_cfq
);
4462 static void __exit
cfq_exit(void)
4464 #ifdef CONFIG_CFQ_GROUP_IOSCHED
4465 blkcg_policy_unregister(&blkcg_policy_cfq
);
4467 elv_unregister(&iosched_cfq
);
4468 kmem_cache_destroy(cfq_pool
);
4471 module_init(cfq_init
);
4472 module_exit(cfq_exit
);
4474 MODULE_AUTHOR("Jens Axboe");
4475 MODULE_LICENSE("GPL");
4476 MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler");