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>
17 #include <linux/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)
70 /* blkio-related constants */
71 #define CFQ_WEIGHT_MIN 10
72 #define CFQ_WEIGHT_MAX 1000
73 #define CFQ_WEIGHT_DEFAULT 500
76 unsigned long last_end_request
;
78 unsigned long ttime_total
;
79 unsigned long ttime_samples
;
80 unsigned long ttime_mean
;
84 * Most of our rbtree usage is for sorting with min extraction, so
85 * if we cache the leftmost node we don't have to walk down the tree
86 * to find it. Idea borrowed from Ingo Molnars CFS scheduler. We should
87 * move this into the elevator for the rq sorting as well.
94 struct cfq_ttime ttime
;
96 #define CFQ_RB_ROOT (struct cfq_rb_root) { .rb = RB_ROOT, \
97 .ttime = {.last_end_request = jiffies,},}
100 * Per process-grouping structure
103 /* reference count */
105 /* various state flags, see below */
107 /* parent cfq_data */
108 struct cfq_data
*cfqd
;
109 /* service_tree member */
110 struct rb_node rb_node
;
111 /* service_tree key */
112 unsigned long rb_key
;
113 /* prio tree member */
114 struct rb_node p_node
;
115 /* prio tree root we belong to, if any */
116 struct rb_root
*p_root
;
117 /* sorted list of pending requests */
118 struct rb_root sort_list
;
119 /* if fifo isn't expired, next request to serve */
120 struct request
*next_rq
;
121 /* requests queued in sort_list */
123 /* currently allocated requests */
125 /* fifo list of requests in sort_list */
126 struct list_head fifo
;
128 /* time when queue got scheduled in to dispatch first request. */
129 unsigned long dispatch_start
;
130 unsigned int allocated_slice
;
131 unsigned int slice_dispatch
;
132 /* time when first request from queue completed and slice started. */
133 unsigned long slice_start
;
134 unsigned long slice_end
;
137 /* pending priority requests */
139 /* number of requests that are on the dispatch list or inside driver */
142 /* io prio of this group */
143 unsigned short ioprio
, org_ioprio
;
144 unsigned short ioprio_class
;
149 sector_t last_request_pos
;
151 struct cfq_rb_root
*service_tree
;
152 struct cfq_queue
*new_cfqq
;
153 struct cfq_group
*cfqg
;
154 /* Number of sectors dispatched from queue in single dispatch round */
155 unsigned long nr_sectors
;
159 * First index in the service_trees.
160 * IDLE is handled separately, so it has negative index
170 * Second index in the service_trees.
174 SYNC_NOIDLE_WORKLOAD
= 1,
179 #ifdef CONFIG_CFQ_GROUP_IOSCHED
180 /* number of ios merged */
181 struct blkg_rwstat merged
;
182 /* total time spent on device in ns, may not be accurate w/ queueing */
183 struct blkg_rwstat service_time
;
184 /* total time spent waiting in scheduler queue in ns */
185 struct blkg_rwstat wait_time
;
186 /* number of IOs queued up */
187 struct blkg_rwstat queued
;
188 /* total sectors transferred */
189 struct blkg_stat sectors
;
190 /* total disk time and nr sectors dispatched by this group */
191 struct blkg_stat time
;
192 #ifdef CONFIG_DEBUG_BLK_CGROUP
193 /* time not charged to this cgroup */
194 struct blkg_stat unaccounted_time
;
195 /* sum of number of ios queued across all samples */
196 struct blkg_stat avg_queue_size_sum
;
197 /* count of samples taken for average */
198 struct blkg_stat avg_queue_size_samples
;
199 /* how many times this group has been removed from service tree */
200 struct blkg_stat dequeue
;
201 /* total time spent waiting for it to be assigned a timeslice. */
202 struct blkg_stat group_wait_time
;
203 /* time spent idling for this blkcg_gq */
204 struct blkg_stat idle_time
;
205 /* total time with empty current active q with other requests queued */
206 struct blkg_stat empty_time
;
207 /* fields after this shouldn't be cleared on stat reset */
208 uint64_t start_group_wait_time
;
209 uint64_t start_idle_time
;
210 uint64_t start_empty_time
;
212 #endif /* CONFIG_DEBUG_BLK_CGROUP */
213 #endif /* CONFIG_CFQ_GROUP_IOSCHED */
216 /* Per-cgroup data */
217 struct cfq_group_data
{
218 /* must be the first member */
219 struct blkcg_policy_data cpd
;
222 unsigned int leaf_weight
;
225 /* This is per cgroup per device grouping structure */
227 /* must be the first member */
228 struct blkg_policy_data pd
;
230 /* group service_tree member */
231 struct rb_node rb_node
;
233 /* group service_tree key */
237 * The number of active cfqgs and sum of their weights under this
238 * cfqg. This covers this cfqg's leaf_weight and all children's
239 * weights, but does not cover weights of further descendants.
241 * If a cfqg is on the service tree, it's active. An active cfqg
242 * also activates its parent and contributes to the children_weight
246 unsigned int children_weight
;
249 * vfraction is the fraction of vdisktime that the tasks in this
250 * cfqg are entitled to. This is determined by compounding the
251 * ratios walking up from this cfqg to the root.
253 * It is in fixed point w/ CFQ_SERVICE_SHIFT and the sum of all
254 * vfractions on a service tree is approximately 1. The sum may
255 * deviate a bit due to rounding errors and fluctuations caused by
256 * cfqgs entering and leaving the service tree.
258 unsigned int vfraction
;
261 * There are two weights - (internal) weight is the weight of this
262 * cfqg against the sibling cfqgs. leaf_weight is the wight of
263 * this cfqg against the child cfqgs. For the root cfqg, both
264 * weights are kept in sync for backward compatibility.
267 unsigned int new_weight
;
268 unsigned int dev_weight
;
270 unsigned int leaf_weight
;
271 unsigned int new_leaf_weight
;
272 unsigned int dev_leaf_weight
;
274 /* number of cfqq currently on this group */
278 * Per group busy queues average. Useful for workload slice calc. We
279 * create the array for each prio class but at run time it is used
280 * only for RT and BE class and slot for IDLE class remains unused.
281 * This is primarily done to avoid confusion and a gcc warning.
283 unsigned int busy_queues_avg
[CFQ_PRIO_NR
];
285 * rr lists of queues with requests. We maintain service trees for
286 * RT and BE classes. These trees are subdivided in subclasses
287 * of SYNC, SYNC_NOIDLE and ASYNC based on workload type. For IDLE
288 * class there is no subclassification and all the cfq queues go on
289 * a single tree service_tree_idle.
290 * Counts are embedded in the cfq_rb_root
292 struct cfq_rb_root service_trees
[2][3];
293 struct cfq_rb_root service_tree_idle
;
295 unsigned long saved_wl_slice
;
296 enum wl_type_t saved_wl_type
;
297 enum wl_class_t saved_wl_class
;
299 /* number of requests that are on the dispatch list or inside driver */
301 struct cfq_ttime ttime
;
302 struct cfqg_stats stats
; /* stats for this cfqg */
304 /* async queue for each priority case */
305 struct cfq_queue
*async_cfqq
[2][IOPRIO_BE_NR
];
306 struct cfq_queue
*async_idle_cfqq
;
311 struct io_cq icq
; /* must be the first member */
312 struct cfq_queue
*cfqq
[2];
313 struct cfq_ttime ttime
;
314 int ioprio
; /* the current ioprio */
315 #ifdef CONFIG_CFQ_GROUP_IOSCHED
316 uint64_t blkcg_serial_nr
; /* the current blkcg serial */
321 * Per block device queue structure
324 struct request_queue
*queue
;
325 /* Root service tree for cfq_groups */
326 struct cfq_rb_root grp_service_tree
;
327 struct cfq_group
*root_group
;
330 * The priority currently being served
332 enum wl_class_t serving_wl_class
;
333 enum wl_type_t serving_wl_type
;
334 unsigned long workload_expires
;
335 struct cfq_group
*serving_group
;
338 * Each priority tree is sorted by next_request position. These
339 * trees are used when determining if two or more queues are
340 * interleaving requests (see cfq_close_cooperator).
342 struct rb_root prio_trees
[CFQ_PRIO_LISTS
];
344 unsigned int busy_queues
;
345 unsigned int busy_sync_queues
;
351 * queue-depth detection
357 * -1 => indeterminate, (cfq will behave as if NCQ is present, to allow better detection)
358 * 1 => NCQ is present (hw_tag_est_depth is the estimated max depth)
361 int hw_tag_est_depth
;
362 unsigned int hw_tag_samples
;
365 * idle window management
367 struct timer_list idle_slice_timer
;
368 struct work_struct unplug_work
;
370 struct cfq_queue
*active_queue
;
371 struct cfq_io_cq
*active_cic
;
373 sector_t last_position
;
376 * tunables, see top of file
378 unsigned int cfq_quantum
;
379 unsigned int cfq_fifo_expire
[2];
380 unsigned int cfq_back_penalty
;
381 unsigned int cfq_back_max
;
382 unsigned int cfq_slice
[2];
383 unsigned int cfq_slice_async_rq
;
384 unsigned int cfq_slice_idle
;
385 unsigned int cfq_group_idle
;
386 unsigned int cfq_latency
;
387 unsigned int cfq_target_latency
;
390 * Fallback dummy cfqq for extreme OOM conditions
392 struct cfq_queue oom_cfqq
;
394 unsigned long last_delayed_sync
;
397 static struct cfq_group
*cfq_get_next_cfqg(struct cfq_data
*cfqd
);
398 static void cfq_put_queue(struct cfq_queue
*cfqq
);
400 static struct cfq_rb_root
*st_for(struct cfq_group
*cfqg
,
401 enum wl_class_t
class,
407 if (class == IDLE_WORKLOAD
)
408 return &cfqg
->service_tree_idle
;
410 return &cfqg
->service_trees
[class][type
];
413 enum cfqq_state_flags
{
414 CFQ_CFQQ_FLAG_on_rr
= 0, /* on round-robin busy list */
415 CFQ_CFQQ_FLAG_wait_request
, /* waiting for a request */
416 CFQ_CFQQ_FLAG_must_dispatch
, /* must be allowed a dispatch */
417 CFQ_CFQQ_FLAG_must_alloc_slice
, /* per-slice must_alloc flag */
418 CFQ_CFQQ_FLAG_fifo_expire
, /* FIFO checked in this slice */
419 CFQ_CFQQ_FLAG_idle_window
, /* slice idling enabled */
420 CFQ_CFQQ_FLAG_prio_changed
, /* task priority has changed */
421 CFQ_CFQQ_FLAG_slice_new
, /* no requests dispatched in slice */
422 CFQ_CFQQ_FLAG_sync
, /* synchronous queue */
423 CFQ_CFQQ_FLAG_coop
, /* cfqq is shared */
424 CFQ_CFQQ_FLAG_split_coop
, /* shared cfqq will be splitted */
425 CFQ_CFQQ_FLAG_deep
, /* sync cfqq experienced large depth */
426 CFQ_CFQQ_FLAG_wait_busy
, /* Waiting for next request */
429 #define CFQ_CFQQ_FNS(name) \
430 static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \
432 (cfqq)->flags |= (1 << CFQ_CFQQ_FLAG_##name); \
434 static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \
436 (cfqq)->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \
438 static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \
440 return ((cfqq)->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \
444 CFQ_CFQQ_FNS(wait_request
);
445 CFQ_CFQQ_FNS(must_dispatch
);
446 CFQ_CFQQ_FNS(must_alloc_slice
);
447 CFQ_CFQQ_FNS(fifo_expire
);
448 CFQ_CFQQ_FNS(idle_window
);
449 CFQ_CFQQ_FNS(prio_changed
);
450 CFQ_CFQQ_FNS(slice_new
);
453 CFQ_CFQQ_FNS(split_coop
);
455 CFQ_CFQQ_FNS(wait_busy
);
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_total(&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_total(&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 inline struct cfq_group
*pd_to_cfqg(struct blkg_policy_data
*pd
)
604 return pd
? container_of(pd
, struct cfq_group
, pd
) : NULL
;
607 static struct cfq_group_data
608 *cpd_to_cfqgd(struct blkcg_policy_data
*cpd
)
610 return cpd
? container_of(cpd
, struct cfq_group_data
, cpd
) : NULL
;
613 static inline struct blkcg_gq
*cfqg_to_blkg(struct cfq_group
*cfqg
)
615 return pd_to_blkg(&cfqg
->pd
);
618 static struct blkcg_policy blkcg_policy_cfq
;
620 static inline struct cfq_group
*blkg_to_cfqg(struct blkcg_gq
*blkg
)
622 return pd_to_cfqg(blkg_to_pd(blkg
, &blkcg_policy_cfq
));
625 static struct cfq_group_data
*blkcg_to_cfqgd(struct blkcg
*blkcg
)
627 return cpd_to_cfqgd(blkcg_to_cpd(blkcg
, &blkcg_policy_cfq
));
630 static inline struct cfq_group
*cfqg_parent(struct cfq_group
*cfqg
)
632 struct blkcg_gq
*pblkg
= cfqg_to_blkg(cfqg
)->parent
;
634 return pblkg
? blkg_to_cfqg(pblkg
) : NULL
;
637 static inline void cfqg_get(struct cfq_group
*cfqg
)
639 return blkg_get(cfqg_to_blkg(cfqg
));
642 static inline void cfqg_put(struct cfq_group
*cfqg
)
644 return blkg_put(cfqg_to_blkg(cfqg
));
647 #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) do { \
650 blkg_path(cfqg_to_blkg((cfqq)->cfqg), __pbuf, sizeof(__pbuf)); \
651 blk_add_trace_msg((cfqd)->queue, "cfq%d%c%c %s " fmt, (cfqq)->pid, \
652 cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \
653 cfqq_type((cfqq)) == SYNC_NOIDLE_WORKLOAD ? 'N' : ' ',\
657 #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) do { \
660 blkg_path(cfqg_to_blkg(cfqg), __pbuf, sizeof(__pbuf)); \
661 blk_add_trace_msg((cfqd)->queue, "%s " fmt, __pbuf, ##args); \
664 static inline void cfqg_stats_update_io_add(struct cfq_group
*cfqg
,
665 struct cfq_group
*curr_cfqg
, int rw
)
667 blkg_rwstat_add(&cfqg
->stats
.queued
, rw
, 1);
668 cfqg_stats_end_empty_time(&cfqg
->stats
);
669 cfqg_stats_set_start_group_wait_time(cfqg
, curr_cfqg
);
672 static inline void cfqg_stats_update_timeslice_used(struct cfq_group
*cfqg
,
673 unsigned long time
, unsigned long unaccounted_time
)
675 blkg_stat_add(&cfqg
->stats
.time
, time
);
676 #ifdef CONFIG_DEBUG_BLK_CGROUP
677 blkg_stat_add(&cfqg
->stats
.unaccounted_time
, unaccounted_time
);
681 static inline void cfqg_stats_update_io_remove(struct cfq_group
*cfqg
, int rw
)
683 blkg_rwstat_add(&cfqg
->stats
.queued
, rw
, -1);
686 static inline void cfqg_stats_update_io_merged(struct cfq_group
*cfqg
, int rw
)
688 blkg_rwstat_add(&cfqg
->stats
.merged
, rw
, 1);
691 static inline void cfqg_stats_update_dispatch(struct cfq_group
*cfqg
,
692 uint64_t bytes
, int rw
)
694 blkg_stat_add(&cfqg
->stats
.sectors
, bytes
>> 9);
697 static inline void cfqg_stats_update_completion(struct cfq_group
*cfqg
,
698 uint64_t start_time
, uint64_t io_start_time
, int rw
)
700 struct cfqg_stats
*stats
= &cfqg
->stats
;
701 unsigned long long now
= sched_clock();
703 if (time_after64(now
, io_start_time
))
704 blkg_rwstat_add(&stats
->service_time
, rw
, now
- io_start_time
);
705 if (time_after64(io_start_time
, start_time
))
706 blkg_rwstat_add(&stats
->wait_time
, rw
,
707 io_start_time
- start_time
);
711 static void cfqg_stats_reset(struct cfqg_stats
*stats
)
713 /* queued stats shouldn't be cleared */
714 blkg_rwstat_reset(&stats
->merged
);
715 blkg_rwstat_reset(&stats
->service_time
);
716 blkg_rwstat_reset(&stats
->wait_time
);
717 blkg_stat_reset(&stats
->time
);
718 #ifdef CONFIG_DEBUG_BLK_CGROUP
719 blkg_stat_reset(&stats
->unaccounted_time
);
720 blkg_stat_reset(&stats
->avg_queue_size_sum
);
721 blkg_stat_reset(&stats
->avg_queue_size_samples
);
722 blkg_stat_reset(&stats
->dequeue
);
723 blkg_stat_reset(&stats
->group_wait_time
);
724 blkg_stat_reset(&stats
->idle_time
);
725 blkg_stat_reset(&stats
->empty_time
);
730 static void cfqg_stats_add_aux(struct cfqg_stats
*to
, struct cfqg_stats
*from
)
732 /* queued stats shouldn't be cleared */
733 blkg_rwstat_add_aux(&to
->merged
, &from
->merged
);
734 blkg_rwstat_add_aux(&to
->service_time
, &from
->service_time
);
735 blkg_rwstat_add_aux(&to
->wait_time
, &from
->wait_time
);
736 blkg_stat_add_aux(&from
->time
, &from
->time
);
737 #ifdef CONFIG_DEBUG_BLK_CGROUP
738 blkg_stat_add_aux(&to
->unaccounted_time
, &from
->unaccounted_time
);
739 blkg_stat_add_aux(&to
->avg_queue_size_sum
, &from
->avg_queue_size_sum
);
740 blkg_stat_add_aux(&to
->avg_queue_size_samples
, &from
->avg_queue_size_samples
);
741 blkg_stat_add_aux(&to
->dequeue
, &from
->dequeue
);
742 blkg_stat_add_aux(&to
->group_wait_time
, &from
->group_wait_time
);
743 blkg_stat_add_aux(&to
->idle_time
, &from
->idle_time
);
744 blkg_stat_add_aux(&to
->empty_time
, &from
->empty_time
);
749 * Transfer @cfqg's stats to its parent's aux counts so that the ancestors'
750 * recursive stats can still account for the amount used by this cfqg after
753 static void cfqg_stats_xfer_dead(struct cfq_group
*cfqg
)
755 struct cfq_group
*parent
= cfqg_parent(cfqg
);
757 lockdep_assert_held(cfqg_to_blkg(cfqg
)->q
->queue_lock
);
759 if (unlikely(!parent
))
762 cfqg_stats_add_aux(&parent
->stats
, &cfqg
->stats
);
763 cfqg_stats_reset(&cfqg
->stats
);
766 #else /* CONFIG_CFQ_GROUP_IOSCHED */
768 static inline struct cfq_group
*cfqg_parent(struct cfq_group
*cfqg
) { return NULL
; }
769 static inline void cfqg_get(struct cfq_group
*cfqg
) { }
770 static inline void cfqg_put(struct cfq_group
*cfqg
) { }
772 #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \
773 blk_add_trace_msg((cfqd)->queue, "cfq%d%c%c " fmt, (cfqq)->pid, \
774 cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \
775 cfqq_type((cfqq)) == SYNC_NOIDLE_WORKLOAD ? 'N' : ' ',\
777 #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) do {} while (0)
779 static inline void cfqg_stats_update_io_add(struct cfq_group
*cfqg
,
780 struct cfq_group
*curr_cfqg
, int rw
) { }
781 static inline void cfqg_stats_update_timeslice_used(struct cfq_group
*cfqg
,
782 unsigned long time
, unsigned long unaccounted_time
) { }
783 static inline void cfqg_stats_update_io_remove(struct cfq_group
*cfqg
, int rw
) { }
784 static inline void cfqg_stats_update_io_merged(struct cfq_group
*cfqg
, int rw
) { }
785 static inline void cfqg_stats_update_dispatch(struct cfq_group
*cfqg
,
786 uint64_t bytes
, int rw
) { }
787 static inline void cfqg_stats_update_completion(struct cfq_group
*cfqg
,
788 uint64_t start_time
, uint64_t io_start_time
, int rw
) { }
790 #endif /* CONFIG_CFQ_GROUP_IOSCHED */
792 #define cfq_log(cfqd, fmt, args...) \
793 blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args)
795 /* Traverses through cfq group service trees */
796 #define for_each_cfqg_st(cfqg, i, j, st) \
797 for (i = 0; i <= IDLE_WORKLOAD; i++) \
798 for (j = 0, st = i < IDLE_WORKLOAD ? &cfqg->service_trees[i][j]\
799 : &cfqg->service_tree_idle; \
800 (i < IDLE_WORKLOAD && j <= SYNC_WORKLOAD) || \
801 (i == IDLE_WORKLOAD && j == 0); \
802 j++, st = i < IDLE_WORKLOAD ? \
803 &cfqg->service_trees[i][j]: NULL) \
805 static inline bool cfq_io_thinktime_big(struct cfq_data *cfqd,
806 struct cfq_ttime
*ttime
, bool group_idle
)
809 if (!sample_valid(ttime
->ttime_samples
))
812 slice
= cfqd
->cfq_group_idle
;
814 slice
= cfqd
->cfq_slice_idle
;
815 return ttime
->ttime_mean
> slice
;
818 static inline bool iops_mode(struct cfq_data
*cfqd
)
821 * If we are not idling on queues and it is a NCQ drive, parallel
822 * execution of requests is on and measuring time is not possible
823 * in most of the cases until and unless we drive shallower queue
824 * depths and that becomes a performance bottleneck. In such cases
825 * switch to start providing fairness in terms of number of IOs.
827 if (!cfqd
->cfq_slice_idle
&& cfqd
->hw_tag
)
833 static inline enum wl_class_t
cfqq_class(struct cfq_queue
*cfqq
)
835 if (cfq_class_idle(cfqq
))
836 return IDLE_WORKLOAD
;
837 if (cfq_class_rt(cfqq
))
843 static enum wl_type_t
cfqq_type(struct cfq_queue
*cfqq
)
845 if (!cfq_cfqq_sync(cfqq
))
846 return ASYNC_WORKLOAD
;
847 if (!cfq_cfqq_idle_window(cfqq
))
848 return SYNC_NOIDLE_WORKLOAD
;
849 return SYNC_WORKLOAD
;
852 static inline int cfq_group_busy_queues_wl(enum wl_class_t wl_class
,
853 struct cfq_data
*cfqd
,
854 struct cfq_group
*cfqg
)
856 if (wl_class
== IDLE_WORKLOAD
)
857 return cfqg
->service_tree_idle
.count
;
859 return cfqg
->service_trees
[wl_class
][ASYNC_WORKLOAD
].count
+
860 cfqg
->service_trees
[wl_class
][SYNC_NOIDLE_WORKLOAD
].count
+
861 cfqg
->service_trees
[wl_class
][SYNC_WORKLOAD
].count
;
864 static inline int cfqg_busy_async_queues(struct cfq_data
*cfqd
,
865 struct cfq_group
*cfqg
)
867 return cfqg
->service_trees
[RT_WORKLOAD
][ASYNC_WORKLOAD
].count
+
868 cfqg
->service_trees
[BE_WORKLOAD
][ASYNC_WORKLOAD
].count
;
871 static void cfq_dispatch_insert(struct request_queue
*, struct request
*);
872 static struct cfq_queue
*cfq_get_queue(struct cfq_data
*cfqd
, bool is_sync
,
873 struct cfq_io_cq
*cic
, struct bio
*bio
);
875 static inline struct cfq_io_cq
*icq_to_cic(struct io_cq
*icq
)
877 /* cic->icq is the first member, %NULL will convert to %NULL */
878 return container_of(icq
, struct cfq_io_cq
, icq
);
881 static inline struct cfq_io_cq
*cfq_cic_lookup(struct cfq_data
*cfqd
,
882 struct io_context
*ioc
)
885 return icq_to_cic(ioc_lookup_icq(ioc
, cfqd
->queue
));
889 static inline struct cfq_queue
*cic_to_cfqq(struct cfq_io_cq
*cic
, bool is_sync
)
891 return cic
->cfqq
[is_sync
];
894 static inline void cic_set_cfqq(struct cfq_io_cq
*cic
, struct cfq_queue
*cfqq
,
897 cic
->cfqq
[is_sync
] = cfqq
;
900 static inline struct cfq_data
*cic_to_cfqd(struct cfq_io_cq
*cic
)
902 return cic
->icq
.q
->elevator
->elevator_data
;
906 * We regard a request as SYNC, if it's either a read or has the SYNC bit
907 * set (in which case it could also be direct WRITE).
909 static inline bool cfq_bio_sync(struct bio
*bio
)
911 return bio_data_dir(bio
) == READ
|| (bio
->bi_rw
& REQ_SYNC
);
915 * scheduler run of queue, if there are requests pending and no one in the
916 * driver that will restart queueing
918 static inline void cfq_schedule_dispatch(struct cfq_data
*cfqd
)
920 if (cfqd
->busy_queues
) {
921 cfq_log(cfqd
, "schedule dispatch");
922 kblockd_schedule_work(&cfqd
->unplug_work
);
927 * Scale schedule slice based on io priority. Use the sync time slice only
928 * if a queue is marked sync and has sync io queued. A sync queue with async
929 * io only, should not get full sync slice length.
931 static inline int cfq_prio_slice(struct cfq_data
*cfqd
, bool sync
,
934 const int base_slice
= cfqd
->cfq_slice
[sync
];
936 WARN_ON(prio
>= IOPRIO_BE_NR
);
938 return base_slice
+ (base_slice
/CFQ_SLICE_SCALE
* (4 - prio
));
942 cfq_prio_to_slice(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
944 return cfq_prio_slice(cfqd
, cfq_cfqq_sync(cfqq
), cfqq
->ioprio
);
948 * cfqg_scale_charge - scale disk time charge according to cfqg weight
949 * @charge: disk time being charged
950 * @vfraction: vfraction of the cfqg, fixed point w/ CFQ_SERVICE_SHIFT
952 * Scale @charge according to @vfraction, which is in range (0, 1]. The
953 * scaling is inversely proportional.
955 * scaled = charge / vfraction
957 * The result is also in fixed point w/ CFQ_SERVICE_SHIFT.
959 static inline u64
cfqg_scale_charge(unsigned long charge
,
960 unsigned int vfraction
)
962 u64 c
= charge
<< CFQ_SERVICE_SHIFT
; /* make it fixed point */
964 /* charge / vfraction */
965 c
<<= CFQ_SERVICE_SHIFT
;
966 do_div(c
, vfraction
);
970 static inline u64
max_vdisktime(u64 min_vdisktime
, u64 vdisktime
)
972 s64 delta
= (s64
)(vdisktime
- min_vdisktime
);
974 min_vdisktime
= vdisktime
;
976 return min_vdisktime
;
979 static inline u64
min_vdisktime(u64 min_vdisktime
, u64 vdisktime
)
981 s64 delta
= (s64
)(vdisktime
- min_vdisktime
);
983 min_vdisktime
= vdisktime
;
985 return min_vdisktime
;
988 static void update_min_vdisktime(struct cfq_rb_root
*st
)
990 struct cfq_group
*cfqg
;
993 cfqg
= rb_entry_cfqg(st
->left
);
994 st
->min_vdisktime
= max_vdisktime(st
->min_vdisktime
,
1000 * get averaged number of queues of RT/BE priority.
1001 * average is updated, with a formula that gives more weight to higher numbers,
1002 * to quickly follows sudden increases and decrease slowly
1005 static inline unsigned cfq_group_get_avg_queues(struct cfq_data
*cfqd
,
1006 struct cfq_group
*cfqg
, bool rt
)
1008 unsigned min_q
, max_q
;
1009 unsigned mult
= cfq_hist_divisor
- 1;
1010 unsigned round
= cfq_hist_divisor
/ 2;
1011 unsigned busy
= cfq_group_busy_queues_wl(rt
, cfqd
, cfqg
);
1013 min_q
= min(cfqg
->busy_queues_avg
[rt
], busy
);
1014 max_q
= max(cfqg
->busy_queues_avg
[rt
], busy
);
1015 cfqg
->busy_queues_avg
[rt
] = (mult
* max_q
+ min_q
+ round
) /
1017 return cfqg
->busy_queues_avg
[rt
];
1020 static inline unsigned
1021 cfq_group_slice(struct cfq_data
*cfqd
, struct cfq_group
*cfqg
)
1023 return cfqd
->cfq_target_latency
* cfqg
->vfraction
>> CFQ_SERVICE_SHIFT
;
1026 static inline unsigned
1027 cfq_scaled_cfqq_slice(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
1029 unsigned slice
= cfq_prio_to_slice(cfqd
, cfqq
);
1030 if (cfqd
->cfq_latency
) {
1032 * interested queues (we consider only the ones with the same
1033 * priority class in the cfq group)
1035 unsigned iq
= cfq_group_get_avg_queues(cfqd
, cfqq
->cfqg
,
1036 cfq_class_rt(cfqq
));
1037 unsigned sync_slice
= cfqd
->cfq_slice
[1];
1038 unsigned expect_latency
= sync_slice
* iq
;
1039 unsigned group_slice
= cfq_group_slice(cfqd
, cfqq
->cfqg
);
1041 if (expect_latency
> group_slice
) {
1042 unsigned base_low_slice
= 2 * cfqd
->cfq_slice_idle
;
1043 /* scale low_slice according to IO priority
1044 * and sync vs async */
1045 unsigned low_slice
=
1046 min(slice
, base_low_slice
* slice
/ sync_slice
);
1047 /* the adapted slice value is scaled to fit all iqs
1048 * into the target latency */
1049 slice
= max(slice
* group_slice
/ expect_latency
,
1057 cfq_set_prio_slice(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
1059 unsigned slice
= cfq_scaled_cfqq_slice(cfqd
, cfqq
);
1061 cfqq
->slice_start
= jiffies
;
1062 cfqq
->slice_end
= jiffies
+ slice
;
1063 cfqq
->allocated_slice
= slice
;
1064 cfq_log_cfqq(cfqd
, cfqq
, "set_slice=%lu", cfqq
->slice_end
- jiffies
);
1068 * We need to wrap this check in cfq_cfqq_slice_new(), since ->slice_end
1069 * isn't valid until the first request from the dispatch is activated
1070 * and the slice time set.
1072 static inline bool cfq_slice_used(struct cfq_queue
*cfqq
)
1074 if (cfq_cfqq_slice_new(cfqq
))
1076 if (time_before(jiffies
, cfqq
->slice_end
))
1083 * Lifted from AS - choose which of rq1 and rq2 that is best served now.
1084 * We choose the request that is closest to the head right now. Distance
1085 * behind the head is penalized and only allowed to a certain extent.
1087 static struct request
*
1088 cfq_choose_req(struct cfq_data
*cfqd
, struct request
*rq1
, struct request
*rq2
, sector_t last
)
1090 sector_t s1
, s2
, d1
= 0, d2
= 0;
1091 unsigned long back_max
;
1092 #define CFQ_RQ1_WRAP 0x01 /* request 1 wraps */
1093 #define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */
1094 unsigned wrap
= 0; /* bit mask: requests behind the disk head? */
1096 if (rq1
== NULL
|| rq1
== rq2
)
1101 if (rq_is_sync(rq1
) != rq_is_sync(rq2
))
1102 return rq_is_sync(rq1
) ? rq1
: rq2
;
1104 if ((rq1
->cmd_flags
^ rq2
->cmd_flags
) & REQ_PRIO
)
1105 return rq1
->cmd_flags
& REQ_PRIO
? rq1
: rq2
;
1107 s1
= blk_rq_pos(rq1
);
1108 s2
= blk_rq_pos(rq2
);
1111 * by definition, 1KiB is 2 sectors
1113 back_max
= cfqd
->cfq_back_max
* 2;
1116 * Strict one way elevator _except_ in the case where we allow
1117 * short backward seeks which are biased as twice the cost of a
1118 * similar forward seek.
1122 else if (s1
+ back_max
>= last
)
1123 d1
= (last
- s1
) * cfqd
->cfq_back_penalty
;
1125 wrap
|= CFQ_RQ1_WRAP
;
1129 else if (s2
+ back_max
>= last
)
1130 d2
= (last
- s2
) * cfqd
->cfq_back_penalty
;
1132 wrap
|= CFQ_RQ2_WRAP
;
1134 /* Found required data */
1137 * By doing switch() on the bit mask "wrap" we avoid having to
1138 * check two variables for all permutations: --> faster!
1141 case 0: /* common case for CFQ: rq1 and rq2 not wrapped */
1157 case (CFQ_RQ1_WRAP
|CFQ_RQ2_WRAP
): /* both rqs wrapped */
1160 * Since both rqs are wrapped,
1161 * start with the one that's further behind head
1162 * (--> only *one* back seek required),
1163 * since back seek takes more time than forward.
1173 * The below is leftmost cache rbtree addon
1175 static struct cfq_queue
*cfq_rb_first(struct cfq_rb_root
*root
)
1177 /* Service tree is empty */
1182 root
->left
= rb_first(&root
->rb
);
1185 return rb_entry(root
->left
, struct cfq_queue
, rb_node
);
1190 static struct cfq_group
*cfq_rb_first_group(struct cfq_rb_root
*root
)
1193 root
->left
= rb_first(&root
->rb
);
1196 return rb_entry_cfqg(root
->left
);
1201 static void rb_erase_init(struct rb_node
*n
, struct rb_root
*root
)
1207 static void cfq_rb_erase(struct rb_node
*n
, struct cfq_rb_root
*root
)
1209 if (root
->left
== n
)
1211 rb_erase_init(n
, &root
->rb
);
1216 * would be nice to take fifo expire time into account as well
1218 static struct request
*
1219 cfq_find_next_rq(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
1220 struct request
*last
)
1222 struct rb_node
*rbnext
= rb_next(&last
->rb_node
);
1223 struct rb_node
*rbprev
= rb_prev(&last
->rb_node
);
1224 struct request
*next
= NULL
, *prev
= NULL
;
1226 BUG_ON(RB_EMPTY_NODE(&last
->rb_node
));
1229 prev
= rb_entry_rq(rbprev
);
1232 next
= rb_entry_rq(rbnext
);
1234 rbnext
= rb_first(&cfqq
->sort_list
);
1235 if (rbnext
&& rbnext
!= &last
->rb_node
)
1236 next
= rb_entry_rq(rbnext
);
1239 return cfq_choose_req(cfqd
, next
, prev
, blk_rq_pos(last
));
1242 static unsigned long cfq_slice_offset(struct cfq_data
*cfqd
,
1243 struct cfq_queue
*cfqq
)
1246 * just an approximation, should be ok.
1248 return (cfqq
->cfqg
->nr_cfqq
- 1) * (cfq_prio_slice(cfqd
, 1, 0) -
1249 cfq_prio_slice(cfqd
, cfq_cfqq_sync(cfqq
), cfqq
->ioprio
));
1253 cfqg_key(struct cfq_rb_root
*st
, struct cfq_group
*cfqg
)
1255 return cfqg
->vdisktime
- st
->min_vdisktime
;
1259 __cfq_group_service_tree_add(struct cfq_rb_root
*st
, struct cfq_group
*cfqg
)
1261 struct rb_node
**node
= &st
->rb
.rb_node
;
1262 struct rb_node
*parent
= NULL
;
1263 struct cfq_group
*__cfqg
;
1264 s64 key
= cfqg_key(st
, cfqg
);
1267 while (*node
!= NULL
) {
1269 __cfqg
= rb_entry_cfqg(parent
);
1271 if (key
< cfqg_key(st
, __cfqg
))
1272 node
= &parent
->rb_left
;
1274 node
= &parent
->rb_right
;
1280 st
->left
= &cfqg
->rb_node
;
1282 rb_link_node(&cfqg
->rb_node
, parent
, node
);
1283 rb_insert_color(&cfqg
->rb_node
, &st
->rb
);
1287 * This has to be called only on activation of cfqg
1290 cfq_update_group_weight(struct cfq_group
*cfqg
)
1292 if (cfqg
->new_weight
) {
1293 cfqg
->weight
= cfqg
->new_weight
;
1294 cfqg
->new_weight
= 0;
1299 cfq_update_group_leaf_weight(struct cfq_group
*cfqg
)
1301 BUG_ON(!RB_EMPTY_NODE(&cfqg
->rb_node
));
1303 if (cfqg
->new_leaf_weight
) {
1304 cfqg
->leaf_weight
= cfqg
->new_leaf_weight
;
1305 cfqg
->new_leaf_weight
= 0;
1310 cfq_group_service_tree_add(struct cfq_rb_root
*st
, struct cfq_group
*cfqg
)
1312 unsigned int vfr
= 1 << CFQ_SERVICE_SHIFT
; /* start with 1 */
1313 struct cfq_group
*pos
= cfqg
;
1314 struct cfq_group
*parent
;
1317 /* add to the service tree */
1318 BUG_ON(!RB_EMPTY_NODE(&cfqg
->rb_node
));
1321 * Update leaf_weight. We cannot update weight at this point
1322 * because cfqg might already have been activated and is
1323 * contributing its current weight to the parent's child_weight.
1325 cfq_update_group_leaf_weight(cfqg
);
1326 __cfq_group_service_tree_add(st
, cfqg
);
1329 * Activate @cfqg and calculate the portion of vfraction @cfqg is
1330 * entitled to. vfraction is calculated by walking the tree
1331 * towards the root calculating the fraction it has at each level.
1332 * The compounded ratio is how much vfraction @cfqg owns.
1334 * Start with the proportion tasks in this cfqg has against active
1335 * children cfqgs - its leaf_weight against children_weight.
1337 propagate
= !pos
->nr_active
++;
1338 pos
->children_weight
+= pos
->leaf_weight
;
1339 vfr
= vfr
* pos
->leaf_weight
/ pos
->children_weight
;
1342 * Compound ->weight walking up the tree. Both activation and
1343 * vfraction calculation are done in the same loop. Propagation
1344 * stops once an already activated node is met. vfraction
1345 * calculation should always continue to the root.
1347 while ((parent
= cfqg_parent(pos
))) {
1349 cfq_update_group_weight(pos
);
1350 propagate
= !parent
->nr_active
++;
1351 parent
->children_weight
+= pos
->weight
;
1353 vfr
= vfr
* pos
->weight
/ parent
->children_weight
;
1357 cfqg
->vfraction
= max_t(unsigned, vfr
, 1);
1361 cfq_group_notify_queue_add(struct cfq_data
*cfqd
, struct cfq_group
*cfqg
)
1363 struct cfq_rb_root
*st
= &cfqd
->grp_service_tree
;
1364 struct cfq_group
*__cfqg
;
1368 if (!RB_EMPTY_NODE(&cfqg
->rb_node
))
1372 * Currently put the group at the end. Later implement something
1373 * so that groups get lesser vtime based on their weights, so that
1374 * if group does not loose all if it was not continuously backlogged.
1376 n
= rb_last(&st
->rb
);
1378 __cfqg
= rb_entry_cfqg(n
);
1379 cfqg
->vdisktime
= __cfqg
->vdisktime
+ CFQ_IDLE_DELAY
;
1381 cfqg
->vdisktime
= st
->min_vdisktime
;
1382 cfq_group_service_tree_add(st
, cfqg
);
1386 cfq_group_service_tree_del(struct cfq_rb_root
*st
, struct cfq_group
*cfqg
)
1388 struct cfq_group
*pos
= cfqg
;
1392 * Undo activation from cfq_group_service_tree_add(). Deactivate
1393 * @cfqg and propagate deactivation upwards.
1395 propagate
= !--pos
->nr_active
;
1396 pos
->children_weight
-= pos
->leaf_weight
;
1399 struct cfq_group
*parent
= cfqg_parent(pos
);
1401 /* @pos has 0 nr_active at this point */
1402 WARN_ON_ONCE(pos
->children_weight
);
1408 propagate
= !--parent
->nr_active
;
1409 parent
->children_weight
-= pos
->weight
;
1413 /* remove from the service tree */
1414 if (!RB_EMPTY_NODE(&cfqg
->rb_node
))
1415 cfq_rb_erase(&cfqg
->rb_node
, st
);
1419 cfq_group_notify_queue_del(struct cfq_data
*cfqd
, struct cfq_group
*cfqg
)
1421 struct cfq_rb_root
*st
= &cfqd
->grp_service_tree
;
1423 BUG_ON(cfqg
->nr_cfqq
< 1);
1426 /* If there are other cfq queues under this group, don't delete it */
1430 cfq_log_cfqg(cfqd
, cfqg
, "del_from_rr group");
1431 cfq_group_service_tree_del(st
, cfqg
);
1432 cfqg
->saved_wl_slice
= 0;
1433 cfqg_stats_update_dequeue(cfqg
);
1436 static inline unsigned int cfq_cfqq_slice_usage(struct cfq_queue
*cfqq
,
1437 unsigned int *unaccounted_time
)
1439 unsigned int slice_used
;
1442 * Queue got expired before even a single request completed or
1443 * got expired immediately after first request completion.
1445 if (!cfqq
->slice_start
|| cfqq
->slice_start
== jiffies
) {
1447 * Also charge the seek time incurred to the group, otherwise
1448 * if there are mutiple queues in the group, each can dispatch
1449 * a single request on seeky media and cause lots of seek time
1450 * and group will never know it.
1452 slice_used
= max_t(unsigned, (jiffies
- cfqq
->dispatch_start
),
1455 slice_used
= jiffies
- cfqq
->slice_start
;
1456 if (slice_used
> cfqq
->allocated_slice
) {
1457 *unaccounted_time
= slice_used
- cfqq
->allocated_slice
;
1458 slice_used
= cfqq
->allocated_slice
;
1460 if (time_after(cfqq
->slice_start
, cfqq
->dispatch_start
))
1461 *unaccounted_time
+= cfqq
->slice_start
-
1462 cfqq
->dispatch_start
;
1468 static void cfq_group_served(struct cfq_data
*cfqd
, struct cfq_group
*cfqg
,
1469 struct cfq_queue
*cfqq
)
1471 struct cfq_rb_root
*st
= &cfqd
->grp_service_tree
;
1472 unsigned int used_sl
, charge
, unaccounted_sl
= 0;
1473 int nr_sync
= cfqg
->nr_cfqq
- cfqg_busy_async_queues(cfqd
, cfqg
)
1474 - cfqg
->service_tree_idle
.count
;
1477 BUG_ON(nr_sync
< 0);
1478 used_sl
= charge
= cfq_cfqq_slice_usage(cfqq
, &unaccounted_sl
);
1480 if (iops_mode(cfqd
))
1481 charge
= cfqq
->slice_dispatch
;
1482 else if (!cfq_cfqq_sync(cfqq
) && !nr_sync
)
1483 charge
= cfqq
->allocated_slice
;
1486 * Can't update vdisktime while on service tree and cfqg->vfraction
1487 * is valid only while on it. Cache vfr, leave the service tree,
1488 * update vdisktime and go back on. The re-addition to the tree
1489 * will also update the weights as necessary.
1491 vfr
= cfqg
->vfraction
;
1492 cfq_group_service_tree_del(st
, cfqg
);
1493 cfqg
->vdisktime
+= cfqg_scale_charge(charge
, vfr
);
1494 cfq_group_service_tree_add(st
, cfqg
);
1496 /* This group is being expired. Save the context */
1497 if (time_after(cfqd
->workload_expires
, jiffies
)) {
1498 cfqg
->saved_wl_slice
= cfqd
->workload_expires
1500 cfqg
->saved_wl_type
= cfqd
->serving_wl_type
;
1501 cfqg
->saved_wl_class
= cfqd
->serving_wl_class
;
1503 cfqg
->saved_wl_slice
= 0;
1505 cfq_log_cfqg(cfqd
, cfqg
, "served: vt=%llu min_vt=%llu", cfqg
->vdisktime
,
1507 cfq_log_cfqq(cfqq
->cfqd
, cfqq
,
1508 "sl_used=%u disp=%u charge=%u iops=%u sect=%lu",
1509 used_sl
, cfqq
->slice_dispatch
, charge
,
1510 iops_mode(cfqd
), cfqq
->nr_sectors
);
1511 cfqg_stats_update_timeslice_used(cfqg
, used_sl
, unaccounted_sl
);
1512 cfqg_stats_set_start_empty_time(cfqg
);
1516 * cfq_init_cfqg_base - initialize base part of a cfq_group
1517 * @cfqg: cfq_group to initialize
1519 * Initialize the base part which is used whether %CONFIG_CFQ_GROUP_IOSCHED
1520 * is enabled or not.
1522 static void cfq_init_cfqg_base(struct cfq_group
*cfqg
)
1524 struct cfq_rb_root
*st
;
1527 for_each_cfqg_st(cfqg
, i
, j
, st
)
1529 RB_CLEAR_NODE(&cfqg
->rb_node
);
1531 cfqg
->ttime
.last_end_request
= jiffies
;
1534 #ifdef CONFIG_CFQ_GROUP_IOSCHED
1535 static void cfqg_stats_exit(struct cfqg_stats
*stats
)
1537 blkg_rwstat_exit(&stats
->merged
);
1538 blkg_rwstat_exit(&stats
->service_time
);
1539 blkg_rwstat_exit(&stats
->wait_time
);
1540 blkg_rwstat_exit(&stats
->queued
);
1542 blkg_stat_exit(&stats
->sectors
);
1543 blkg_stat_exit(&stats
->time
);
1544 #ifdef CONFIG_DEBUG_BLK_CGROUP
1545 blkg_stat_exit(&stats
->unaccounted_time
);
1546 blkg_stat_exit(&stats
->avg_queue_size_sum
);
1547 blkg_stat_exit(&stats
->avg_queue_size_samples
);
1548 blkg_stat_exit(&stats
->dequeue
);
1549 blkg_stat_exit(&stats
->group_wait_time
);
1550 blkg_stat_exit(&stats
->idle_time
);
1551 blkg_stat_exit(&stats
->empty_time
);
1555 static int cfqg_stats_init(struct cfqg_stats
*stats
, gfp_t gfp
)
1557 if (blkg_rwstat_init(&stats
->merged
, gfp
) ||
1558 blkg_rwstat_init(&stats
->service_time
, gfp
) ||
1559 blkg_rwstat_init(&stats
->wait_time
, gfp
) ||
1560 blkg_rwstat_init(&stats
->queued
, gfp
) ||
1562 blkg_stat_init(&stats
->sectors
, gfp
) ||
1563 blkg_stat_init(&stats
->time
, gfp
))
1566 #ifdef CONFIG_DEBUG_BLK_CGROUP
1567 if (blkg_stat_init(&stats
->unaccounted_time
, gfp
) ||
1568 blkg_stat_init(&stats
->avg_queue_size_sum
, gfp
) ||
1569 blkg_stat_init(&stats
->avg_queue_size_samples
, gfp
) ||
1570 blkg_stat_init(&stats
->dequeue
, gfp
) ||
1571 blkg_stat_init(&stats
->group_wait_time
, gfp
) ||
1572 blkg_stat_init(&stats
->idle_time
, gfp
) ||
1573 blkg_stat_init(&stats
->empty_time
, gfp
))
1578 cfqg_stats_exit(stats
);
1582 static struct blkcg_policy_data
*cfq_cpd_alloc(gfp_t gfp
)
1584 struct cfq_group_data
*cgd
;
1586 cgd
= kzalloc(sizeof(*cgd
), GFP_KERNEL
);
1592 static void cfq_cpd_init(struct blkcg_policy_data
*cpd
)
1594 struct cfq_group_data
*cgd
= cpd_to_cfqgd(cpd
);
1596 if (cpd_to_blkcg(cpd
) == &blkcg_root
) {
1597 cgd
->weight
= 2 * CFQ_WEIGHT_DEFAULT
;
1598 cgd
->leaf_weight
= 2 * CFQ_WEIGHT_DEFAULT
;
1600 cgd
->weight
= CFQ_WEIGHT_DEFAULT
;
1601 cgd
->leaf_weight
= CFQ_WEIGHT_DEFAULT
;
1605 static void cfq_cpd_free(struct blkcg_policy_data
*cpd
)
1607 kfree(cpd_to_cfqgd(cpd
));
1610 static struct blkg_policy_data
*cfq_pd_alloc(gfp_t gfp
, int node
)
1612 struct cfq_group
*cfqg
;
1614 cfqg
= kzalloc_node(sizeof(*cfqg
), gfp
, node
);
1618 cfq_init_cfqg_base(cfqg
);
1619 if (cfqg_stats_init(&cfqg
->stats
, gfp
)) {
1627 static void cfq_pd_init(struct blkg_policy_data
*pd
)
1629 struct cfq_group
*cfqg
= pd_to_cfqg(pd
);
1630 struct cfq_group_data
*cgd
= blkcg_to_cfqgd(pd
->blkg
->blkcg
);
1632 cfqg
->weight
= cgd
->weight
;
1633 cfqg
->leaf_weight
= cgd
->leaf_weight
;
1636 static void cfq_pd_offline(struct blkg_policy_data
*pd
)
1638 struct cfq_group
*cfqg
= pd_to_cfqg(pd
);
1641 for (i
= 0; i
< IOPRIO_BE_NR
; i
++) {
1642 if (cfqg
->async_cfqq
[0][i
])
1643 cfq_put_queue(cfqg
->async_cfqq
[0][i
]);
1644 if (cfqg
->async_cfqq
[1][i
])
1645 cfq_put_queue(cfqg
->async_cfqq
[1][i
]);
1648 if (cfqg
->async_idle_cfqq
)
1649 cfq_put_queue(cfqg
->async_idle_cfqq
);
1652 * @blkg is going offline and will be ignored by
1653 * blkg_[rw]stat_recursive_sum(). Transfer stats to the parent so
1654 * that they don't get lost. If IOs complete after this point, the
1655 * stats for them will be lost. Oh well...
1657 cfqg_stats_xfer_dead(cfqg
);
1660 static void cfq_pd_free(struct blkg_policy_data
*pd
)
1662 struct cfq_group
*cfqg
= pd_to_cfqg(pd
);
1664 cfqg_stats_exit(&cfqg
->stats
);
1668 static void cfq_pd_reset_stats(struct blkg_policy_data
*pd
)
1670 struct cfq_group
*cfqg
= pd_to_cfqg(pd
);
1672 cfqg_stats_reset(&cfqg
->stats
);
1675 static struct cfq_group
*cfq_lookup_cfqg(struct cfq_data
*cfqd
,
1676 struct blkcg
*blkcg
)
1678 struct blkcg_gq
*blkg
;
1680 blkg
= blkg_lookup(blkcg
, cfqd
->queue
);
1682 return blkg_to_cfqg(blkg
);
1686 static void cfq_link_cfqq_cfqg(struct cfq_queue
*cfqq
, struct cfq_group
*cfqg
)
1689 /* cfqq reference on cfqg */
1693 static u64
cfqg_prfill_weight_device(struct seq_file
*sf
,
1694 struct blkg_policy_data
*pd
, int off
)
1696 struct cfq_group
*cfqg
= pd_to_cfqg(pd
);
1698 if (!cfqg
->dev_weight
)
1700 return __blkg_prfill_u64(sf
, pd
, cfqg
->dev_weight
);
1703 static int cfqg_print_weight_device(struct seq_file
*sf
, void *v
)
1705 blkcg_print_blkgs(sf
, css_to_blkcg(seq_css(sf
)),
1706 cfqg_prfill_weight_device
, &blkcg_policy_cfq
,
1711 static u64
cfqg_prfill_leaf_weight_device(struct seq_file
*sf
,
1712 struct blkg_policy_data
*pd
, int off
)
1714 struct cfq_group
*cfqg
= pd_to_cfqg(pd
);
1716 if (!cfqg
->dev_leaf_weight
)
1718 return __blkg_prfill_u64(sf
, pd
, cfqg
->dev_leaf_weight
);
1721 static int cfqg_print_leaf_weight_device(struct seq_file
*sf
, void *v
)
1723 blkcg_print_blkgs(sf
, css_to_blkcg(seq_css(sf
)),
1724 cfqg_prfill_leaf_weight_device
, &blkcg_policy_cfq
,
1729 static int cfq_print_weight(struct seq_file
*sf
, void *v
)
1731 struct blkcg
*blkcg
= css_to_blkcg(seq_css(sf
));
1732 struct cfq_group_data
*cgd
= blkcg_to_cfqgd(blkcg
);
1733 unsigned int val
= 0;
1738 seq_printf(sf
, "%u\n", val
);
1742 static int cfq_print_leaf_weight(struct seq_file
*sf
, void *v
)
1744 struct blkcg
*blkcg
= css_to_blkcg(seq_css(sf
));
1745 struct cfq_group_data
*cgd
= blkcg_to_cfqgd(blkcg
);
1746 unsigned int val
= 0;
1749 val
= cgd
->leaf_weight
;
1751 seq_printf(sf
, "%u\n", val
);
1755 static ssize_t
__cfqg_set_weight_device(struct kernfs_open_file
*of
,
1756 char *buf
, size_t nbytes
, loff_t off
,
1757 bool is_leaf_weight
)
1759 struct blkcg
*blkcg
= css_to_blkcg(of_css(of
));
1760 struct blkg_conf_ctx ctx
;
1761 struct cfq_group
*cfqg
;
1762 struct cfq_group_data
*cfqgd
;
1765 ret
= blkg_conf_prep(blkcg
, &blkcg_policy_cfq
, buf
, &ctx
);
1770 cfqg
= blkg_to_cfqg(ctx
.blkg
);
1771 cfqgd
= blkcg_to_cfqgd(blkcg
);
1772 if (!cfqg
|| !cfqgd
)
1775 if (!ctx
.v
|| (ctx
.v
>= CFQ_WEIGHT_MIN
&& ctx
.v
<= CFQ_WEIGHT_MAX
)) {
1776 if (!is_leaf_weight
) {
1777 cfqg
->dev_weight
= ctx
.v
;
1778 cfqg
->new_weight
= ctx
.v
?: cfqgd
->weight
;
1780 cfqg
->dev_leaf_weight
= ctx
.v
;
1781 cfqg
->new_leaf_weight
= ctx
.v
?: cfqgd
->leaf_weight
;
1787 blkg_conf_finish(&ctx
);
1788 return ret
?: nbytes
;
1791 static ssize_t
cfqg_set_weight_device(struct kernfs_open_file
*of
,
1792 char *buf
, size_t nbytes
, loff_t off
)
1794 return __cfqg_set_weight_device(of
, buf
, nbytes
, off
, false);
1797 static ssize_t
cfqg_set_leaf_weight_device(struct kernfs_open_file
*of
,
1798 char *buf
, size_t nbytes
, loff_t off
)
1800 return __cfqg_set_weight_device(of
, buf
, nbytes
, off
, true);
1803 static int __cfq_set_weight(struct cgroup_subsys_state
*css
, struct cftype
*cft
,
1804 u64 val
, bool is_leaf_weight
)
1806 struct blkcg
*blkcg
= css_to_blkcg(css
);
1807 struct blkcg_gq
*blkg
;
1808 struct cfq_group_data
*cfqgd
;
1811 if (val
< CFQ_WEIGHT_MIN
|| val
> CFQ_WEIGHT_MAX
)
1814 spin_lock_irq(&blkcg
->lock
);
1815 cfqgd
= blkcg_to_cfqgd(blkcg
);
1821 if (!is_leaf_weight
)
1822 cfqgd
->weight
= val
;
1824 cfqgd
->leaf_weight
= val
;
1826 hlist_for_each_entry(blkg
, &blkcg
->blkg_list
, blkcg_node
) {
1827 struct cfq_group
*cfqg
= blkg_to_cfqg(blkg
);
1832 if (!is_leaf_weight
) {
1833 if (!cfqg
->dev_weight
)
1834 cfqg
->new_weight
= cfqgd
->weight
;
1836 if (!cfqg
->dev_leaf_weight
)
1837 cfqg
->new_leaf_weight
= cfqgd
->leaf_weight
;
1842 spin_unlock_irq(&blkcg
->lock
);
1846 static int cfq_set_weight(struct cgroup_subsys_state
*css
, struct cftype
*cft
,
1849 return __cfq_set_weight(css
, cft
, val
, false);
1852 static int cfq_set_leaf_weight(struct cgroup_subsys_state
*css
,
1853 struct cftype
*cft
, u64 val
)
1855 return __cfq_set_weight(css
, cft
, val
, true);
1858 static int cfqg_print_stat(struct seq_file
*sf
, void *v
)
1860 blkcg_print_blkgs(sf
, css_to_blkcg(seq_css(sf
)), blkg_prfill_stat
,
1861 &blkcg_policy_cfq
, seq_cft(sf
)->private, false);
1865 static int cfqg_print_rwstat(struct seq_file
*sf
, void *v
)
1867 blkcg_print_blkgs(sf
, css_to_blkcg(seq_css(sf
)), blkg_prfill_rwstat
,
1868 &blkcg_policy_cfq
, seq_cft(sf
)->private, true);
1872 static u64
cfqg_prfill_stat_recursive(struct seq_file
*sf
,
1873 struct blkg_policy_data
*pd
, int off
)
1875 u64 sum
= blkg_stat_recursive_sum(pd_to_blkg(pd
),
1876 &blkcg_policy_cfq
, off
);
1877 return __blkg_prfill_u64(sf
, pd
, sum
);
1880 static u64
cfqg_prfill_rwstat_recursive(struct seq_file
*sf
,
1881 struct blkg_policy_data
*pd
, int off
)
1883 struct blkg_rwstat sum
= blkg_rwstat_recursive_sum(pd_to_blkg(pd
),
1884 &blkcg_policy_cfq
, off
);
1885 return __blkg_prfill_rwstat(sf
, pd
, &sum
);
1888 static int cfqg_print_stat_recursive(struct seq_file
*sf
, void *v
)
1890 blkcg_print_blkgs(sf
, css_to_blkcg(seq_css(sf
)),
1891 cfqg_prfill_stat_recursive
, &blkcg_policy_cfq
,
1892 seq_cft(sf
)->private, false);
1896 static int cfqg_print_rwstat_recursive(struct seq_file
*sf
, void *v
)
1898 blkcg_print_blkgs(sf
, css_to_blkcg(seq_css(sf
)),
1899 cfqg_prfill_rwstat_recursive
, &blkcg_policy_cfq
,
1900 seq_cft(sf
)->private, true);
1904 #ifdef CONFIG_DEBUG_BLK_CGROUP
1905 static u64
cfqg_prfill_avg_queue_size(struct seq_file
*sf
,
1906 struct blkg_policy_data
*pd
, int off
)
1908 struct cfq_group
*cfqg
= pd_to_cfqg(pd
);
1909 u64 samples
= blkg_stat_read(&cfqg
->stats
.avg_queue_size_samples
);
1913 v
= blkg_stat_read(&cfqg
->stats
.avg_queue_size_sum
);
1914 v
= div64_u64(v
, samples
);
1916 __blkg_prfill_u64(sf
, pd
, v
);
1920 /* print avg_queue_size */
1921 static int cfqg_print_avg_queue_size(struct seq_file
*sf
, void *v
)
1923 blkcg_print_blkgs(sf
, css_to_blkcg(seq_css(sf
)),
1924 cfqg_prfill_avg_queue_size
, &blkcg_policy_cfq
,
1928 #endif /* CONFIG_DEBUG_BLK_CGROUP */
1930 static struct cftype cfq_blkcg_files
[] = {
1931 /* on root, weight is mapped to leaf_weight */
1933 .name
= "weight_device",
1934 .flags
= CFTYPE_ONLY_ON_ROOT
,
1935 .seq_show
= cfqg_print_leaf_weight_device
,
1936 .write
= cfqg_set_leaf_weight_device
,
1940 .flags
= CFTYPE_ONLY_ON_ROOT
,
1941 .seq_show
= cfq_print_leaf_weight
,
1942 .write_u64
= cfq_set_leaf_weight
,
1945 /* no such mapping necessary for !roots */
1947 .name
= "weight_device",
1948 .flags
= CFTYPE_NOT_ON_ROOT
,
1949 .seq_show
= cfqg_print_weight_device
,
1950 .write
= cfqg_set_weight_device
,
1954 .flags
= CFTYPE_NOT_ON_ROOT
,
1955 .seq_show
= cfq_print_weight
,
1956 .write_u64
= cfq_set_weight
,
1960 .name
= "leaf_weight_device",
1961 .seq_show
= cfqg_print_leaf_weight_device
,
1962 .write
= cfqg_set_leaf_weight_device
,
1965 .name
= "leaf_weight",
1966 .seq_show
= cfq_print_leaf_weight
,
1967 .write_u64
= cfq_set_leaf_weight
,
1970 /* statistics, covers only the tasks in the cfqg */
1973 .private = offsetof(struct cfq_group
, stats
.time
),
1974 .seq_show
= cfqg_print_stat
,
1978 .private = offsetof(struct cfq_group
, stats
.sectors
),
1979 .seq_show
= cfqg_print_stat
,
1982 .name
= "io_service_bytes",
1983 .private = (unsigned long)&blkcg_policy_cfq
,
1984 .seq_show
= blkg_print_stat_bytes
,
1987 .name
= "io_serviced",
1988 .private = (unsigned long)&blkcg_policy_cfq
,
1989 .seq_show
= blkg_print_stat_ios
,
1992 .name
= "io_service_time",
1993 .private = offsetof(struct cfq_group
, stats
.service_time
),
1994 .seq_show
= cfqg_print_rwstat
,
1997 .name
= "io_wait_time",
1998 .private = offsetof(struct cfq_group
, stats
.wait_time
),
1999 .seq_show
= cfqg_print_rwstat
,
2002 .name
= "io_merged",
2003 .private = offsetof(struct cfq_group
, stats
.merged
),
2004 .seq_show
= cfqg_print_rwstat
,
2007 .name
= "io_queued",
2008 .private = offsetof(struct cfq_group
, stats
.queued
),
2009 .seq_show
= cfqg_print_rwstat
,
2012 /* the same statictics which cover the cfqg and its descendants */
2014 .name
= "time_recursive",
2015 .private = offsetof(struct cfq_group
, stats
.time
),
2016 .seq_show
= cfqg_print_stat_recursive
,
2019 .name
= "sectors_recursive",
2020 .private = offsetof(struct cfq_group
, stats
.sectors
),
2021 .seq_show
= cfqg_print_stat_recursive
,
2024 .name
= "io_service_bytes_recursive",
2025 .private = (unsigned long)&blkcg_policy_cfq
,
2026 .seq_show
= blkg_print_stat_bytes_recursive
,
2029 .name
= "io_serviced_recursive",
2030 .private = (unsigned long)&blkcg_policy_cfq
,
2031 .seq_show
= blkg_print_stat_ios_recursive
,
2034 .name
= "io_service_time_recursive",
2035 .private = offsetof(struct cfq_group
, stats
.service_time
),
2036 .seq_show
= cfqg_print_rwstat_recursive
,
2039 .name
= "io_wait_time_recursive",
2040 .private = offsetof(struct cfq_group
, stats
.wait_time
),
2041 .seq_show
= cfqg_print_rwstat_recursive
,
2044 .name
= "io_merged_recursive",
2045 .private = offsetof(struct cfq_group
, stats
.merged
),
2046 .seq_show
= cfqg_print_rwstat_recursive
,
2049 .name
= "io_queued_recursive",
2050 .private = offsetof(struct cfq_group
, stats
.queued
),
2051 .seq_show
= cfqg_print_rwstat_recursive
,
2053 #ifdef CONFIG_DEBUG_BLK_CGROUP
2055 .name
= "avg_queue_size",
2056 .seq_show
= cfqg_print_avg_queue_size
,
2059 .name
= "group_wait_time",
2060 .private = offsetof(struct cfq_group
, stats
.group_wait_time
),
2061 .seq_show
= cfqg_print_stat
,
2064 .name
= "idle_time",
2065 .private = offsetof(struct cfq_group
, stats
.idle_time
),
2066 .seq_show
= cfqg_print_stat
,
2069 .name
= "empty_time",
2070 .private = offsetof(struct cfq_group
, stats
.empty_time
),
2071 .seq_show
= cfqg_print_stat
,
2075 .private = offsetof(struct cfq_group
, stats
.dequeue
),
2076 .seq_show
= cfqg_print_stat
,
2079 .name
= "unaccounted_time",
2080 .private = offsetof(struct cfq_group
, stats
.unaccounted_time
),
2081 .seq_show
= cfqg_print_stat
,
2083 #endif /* CONFIG_DEBUG_BLK_CGROUP */
2086 #else /* GROUP_IOSCHED */
2087 static struct cfq_group
*cfq_lookup_cfqg(struct cfq_data
*cfqd
,
2088 struct blkcg
*blkcg
)
2090 return cfqd
->root_group
;
2094 cfq_link_cfqq_cfqg(struct cfq_queue
*cfqq
, struct cfq_group
*cfqg
) {
2098 #endif /* GROUP_IOSCHED */
2101 * The cfqd->service_trees holds all pending cfq_queue's that have
2102 * requests waiting to be processed. It is sorted in the order that
2103 * we will service the queues.
2105 static void cfq_service_tree_add(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
2108 struct rb_node
**p
, *parent
;
2109 struct cfq_queue
*__cfqq
;
2110 unsigned long rb_key
;
2111 struct cfq_rb_root
*st
;
2115 st
= st_for(cfqq
->cfqg
, cfqq_class(cfqq
), cfqq_type(cfqq
));
2116 if (cfq_class_idle(cfqq
)) {
2117 rb_key
= CFQ_IDLE_DELAY
;
2118 parent
= rb_last(&st
->rb
);
2119 if (parent
&& parent
!= &cfqq
->rb_node
) {
2120 __cfqq
= rb_entry(parent
, struct cfq_queue
, rb_node
);
2121 rb_key
+= __cfqq
->rb_key
;
2124 } else if (!add_front
) {
2126 * Get our rb key offset. Subtract any residual slice
2127 * value carried from last service. A negative resid
2128 * count indicates slice overrun, and this should position
2129 * the next service time further away in the tree.
2131 rb_key
= cfq_slice_offset(cfqd
, cfqq
) + jiffies
;
2132 rb_key
-= cfqq
->slice_resid
;
2133 cfqq
->slice_resid
= 0;
2136 __cfqq
= cfq_rb_first(st
);
2137 rb_key
+= __cfqq
? __cfqq
->rb_key
: jiffies
;
2140 if (!RB_EMPTY_NODE(&cfqq
->rb_node
)) {
2143 * same position, nothing more to do
2145 if (rb_key
== cfqq
->rb_key
&& cfqq
->service_tree
== st
)
2148 cfq_rb_erase(&cfqq
->rb_node
, cfqq
->service_tree
);
2149 cfqq
->service_tree
= NULL
;
2154 cfqq
->service_tree
= st
;
2155 p
= &st
->rb
.rb_node
;
2158 __cfqq
= rb_entry(parent
, struct cfq_queue
, rb_node
);
2161 * sort by key, that represents service time.
2163 if (time_before(rb_key
, __cfqq
->rb_key
))
2164 p
= &parent
->rb_left
;
2166 p
= &parent
->rb_right
;
2172 st
->left
= &cfqq
->rb_node
;
2174 cfqq
->rb_key
= rb_key
;
2175 rb_link_node(&cfqq
->rb_node
, parent
, p
);
2176 rb_insert_color(&cfqq
->rb_node
, &st
->rb
);
2178 if (add_front
|| !new_cfqq
)
2180 cfq_group_notify_queue_add(cfqd
, cfqq
->cfqg
);
2183 static struct cfq_queue
*
2184 cfq_prio_tree_lookup(struct cfq_data
*cfqd
, struct rb_root
*root
,
2185 sector_t sector
, struct rb_node
**ret_parent
,
2186 struct rb_node
***rb_link
)
2188 struct rb_node
**p
, *parent
;
2189 struct cfq_queue
*cfqq
= NULL
;
2197 cfqq
= rb_entry(parent
, struct cfq_queue
, p_node
);
2200 * Sort strictly based on sector. Smallest to the left,
2201 * largest to the right.
2203 if (sector
> blk_rq_pos(cfqq
->next_rq
))
2204 n
= &(*p
)->rb_right
;
2205 else if (sector
< blk_rq_pos(cfqq
->next_rq
))
2213 *ret_parent
= parent
;
2219 static void cfq_prio_tree_add(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
2221 struct rb_node
**p
, *parent
;
2222 struct cfq_queue
*__cfqq
;
2225 rb_erase(&cfqq
->p_node
, cfqq
->p_root
);
2226 cfqq
->p_root
= NULL
;
2229 if (cfq_class_idle(cfqq
))
2234 cfqq
->p_root
= &cfqd
->prio_trees
[cfqq
->org_ioprio
];
2235 __cfqq
= cfq_prio_tree_lookup(cfqd
, cfqq
->p_root
,
2236 blk_rq_pos(cfqq
->next_rq
), &parent
, &p
);
2238 rb_link_node(&cfqq
->p_node
, parent
, p
);
2239 rb_insert_color(&cfqq
->p_node
, cfqq
->p_root
);
2241 cfqq
->p_root
= NULL
;
2245 * Update cfqq's position in the service tree.
2247 static void cfq_resort_rr_list(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
2250 * Resorting requires the cfqq to be on the RR list already.
2252 if (cfq_cfqq_on_rr(cfqq
)) {
2253 cfq_service_tree_add(cfqd
, cfqq
, 0);
2254 cfq_prio_tree_add(cfqd
, cfqq
);
2259 * add to busy list of queues for service, trying to be fair in ordering
2260 * the pending list according to last request service
2262 static void cfq_add_cfqq_rr(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
2264 cfq_log_cfqq(cfqd
, cfqq
, "add_to_rr");
2265 BUG_ON(cfq_cfqq_on_rr(cfqq
));
2266 cfq_mark_cfqq_on_rr(cfqq
);
2267 cfqd
->busy_queues
++;
2268 if (cfq_cfqq_sync(cfqq
))
2269 cfqd
->busy_sync_queues
++;
2271 cfq_resort_rr_list(cfqd
, cfqq
);
2275 * Called when the cfqq no longer has requests pending, remove it from
2278 static void cfq_del_cfqq_rr(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
2280 cfq_log_cfqq(cfqd
, cfqq
, "del_from_rr");
2281 BUG_ON(!cfq_cfqq_on_rr(cfqq
));
2282 cfq_clear_cfqq_on_rr(cfqq
);
2284 if (!RB_EMPTY_NODE(&cfqq
->rb_node
)) {
2285 cfq_rb_erase(&cfqq
->rb_node
, cfqq
->service_tree
);
2286 cfqq
->service_tree
= NULL
;
2289 rb_erase(&cfqq
->p_node
, cfqq
->p_root
);
2290 cfqq
->p_root
= NULL
;
2293 cfq_group_notify_queue_del(cfqd
, cfqq
->cfqg
);
2294 BUG_ON(!cfqd
->busy_queues
);
2295 cfqd
->busy_queues
--;
2296 if (cfq_cfqq_sync(cfqq
))
2297 cfqd
->busy_sync_queues
--;
2301 * rb tree support functions
2303 static void cfq_del_rq_rb(struct request
*rq
)
2305 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
2306 const int sync
= rq_is_sync(rq
);
2308 BUG_ON(!cfqq
->queued
[sync
]);
2309 cfqq
->queued
[sync
]--;
2311 elv_rb_del(&cfqq
->sort_list
, rq
);
2313 if (cfq_cfqq_on_rr(cfqq
) && RB_EMPTY_ROOT(&cfqq
->sort_list
)) {
2315 * Queue will be deleted from service tree when we actually
2316 * expire it later. Right now just remove it from prio tree
2320 rb_erase(&cfqq
->p_node
, cfqq
->p_root
);
2321 cfqq
->p_root
= NULL
;
2326 static void cfq_add_rq_rb(struct request
*rq
)
2328 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
2329 struct cfq_data
*cfqd
= cfqq
->cfqd
;
2330 struct request
*prev
;
2332 cfqq
->queued
[rq_is_sync(rq
)]++;
2334 elv_rb_add(&cfqq
->sort_list
, rq
);
2336 if (!cfq_cfqq_on_rr(cfqq
))
2337 cfq_add_cfqq_rr(cfqd
, cfqq
);
2340 * check if this request is a better next-serve candidate
2342 prev
= cfqq
->next_rq
;
2343 cfqq
->next_rq
= cfq_choose_req(cfqd
, cfqq
->next_rq
, rq
, cfqd
->last_position
);
2346 * adjust priority tree position, if ->next_rq changes
2348 if (prev
!= cfqq
->next_rq
)
2349 cfq_prio_tree_add(cfqd
, cfqq
);
2351 BUG_ON(!cfqq
->next_rq
);
2354 static void cfq_reposition_rq_rb(struct cfq_queue
*cfqq
, struct request
*rq
)
2356 elv_rb_del(&cfqq
->sort_list
, rq
);
2357 cfqq
->queued
[rq_is_sync(rq
)]--;
2358 cfqg_stats_update_io_remove(RQ_CFQG(rq
), rq
->cmd_flags
);
2360 cfqg_stats_update_io_add(RQ_CFQG(rq
), cfqq
->cfqd
->serving_group
,
2364 static struct request
*
2365 cfq_find_rq_fmerge(struct cfq_data
*cfqd
, struct bio
*bio
)
2367 struct task_struct
*tsk
= current
;
2368 struct cfq_io_cq
*cic
;
2369 struct cfq_queue
*cfqq
;
2371 cic
= cfq_cic_lookup(cfqd
, tsk
->io_context
);
2375 cfqq
= cic_to_cfqq(cic
, cfq_bio_sync(bio
));
2377 return elv_rb_find(&cfqq
->sort_list
, bio_end_sector(bio
));
2382 static void cfq_activate_request(struct request_queue
*q
, struct request
*rq
)
2384 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
2386 cfqd
->rq_in_driver
++;
2387 cfq_log_cfqq(cfqd
, RQ_CFQQ(rq
), "activate rq, drv=%d",
2388 cfqd
->rq_in_driver
);
2390 cfqd
->last_position
= blk_rq_pos(rq
) + blk_rq_sectors(rq
);
2393 static void cfq_deactivate_request(struct request_queue
*q
, struct request
*rq
)
2395 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
2397 WARN_ON(!cfqd
->rq_in_driver
);
2398 cfqd
->rq_in_driver
--;
2399 cfq_log_cfqq(cfqd
, RQ_CFQQ(rq
), "deactivate rq, drv=%d",
2400 cfqd
->rq_in_driver
);
2403 static void cfq_remove_request(struct request
*rq
)
2405 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
2407 if (cfqq
->next_rq
== rq
)
2408 cfqq
->next_rq
= cfq_find_next_rq(cfqq
->cfqd
, cfqq
, rq
);
2410 list_del_init(&rq
->queuelist
);
2413 cfqq
->cfqd
->rq_queued
--;
2414 cfqg_stats_update_io_remove(RQ_CFQG(rq
), rq
->cmd_flags
);
2415 if (rq
->cmd_flags
& REQ_PRIO
) {
2416 WARN_ON(!cfqq
->prio_pending
);
2417 cfqq
->prio_pending
--;
2421 static int cfq_merge(struct request_queue
*q
, struct request
**req
,
2424 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
2425 struct request
*__rq
;
2427 __rq
= cfq_find_rq_fmerge(cfqd
, bio
);
2428 if (__rq
&& elv_rq_merge_ok(__rq
, bio
)) {
2430 return ELEVATOR_FRONT_MERGE
;
2433 return ELEVATOR_NO_MERGE
;
2436 static void cfq_merged_request(struct request_queue
*q
, struct request
*req
,
2439 if (type
== ELEVATOR_FRONT_MERGE
) {
2440 struct cfq_queue
*cfqq
= RQ_CFQQ(req
);
2442 cfq_reposition_rq_rb(cfqq
, req
);
2446 static void cfq_bio_merged(struct request_queue
*q
, struct request
*req
,
2449 cfqg_stats_update_io_merged(RQ_CFQG(req
), bio
->bi_rw
);
2453 cfq_merged_requests(struct request_queue
*q
, struct request
*rq
,
2454 struct request
*next
)
2456 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
2457 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
2460 * reposition in fifo if next is older than rq
2462 if (!list_empty(&rq
->queuelist
) && !list_empty(&next
->queuelist
) &&
2463 time_before(next
->fifo_time
, rq
->fifo_time
) &&
2464 cfqq
== RQ_CFQQ(next
)) {
2465 list_move(&rq
->queuelist
, &next
->queuelist
);
2466 rq
->fifo_time
= next
->fifo_time
;
2469 if (cfqq
->next_rq
== next
)
2471 cfq_remove_request(next
);
2472 cfqg_stats_update_io_merged(RQ_CFQG(rq
), next
->cmd_flags
);
2474 cfqq
= RQ_CFQQ(next
);
2476 * all requests of this queue are merged to other queues, delete it
2477 * from the service tree. If it's the active_queue,
2478 * cfq_dispatch_requests() will choose to expire it or do idle
2480 if (cfq_cfqq_on_rr(cfqq
) && RB_EMPTY_ROOT(&cfqq
->sort_list
) &&
2481 cfqq
!= cfqd
->active_queue
)
2482 cfq_del_cfqq_rr(cfqd
, cfqq
);
2485 static int cfq_allow_merge(struct request_queue
*q
, struct request
*rq
,
2488 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
2489 struct cfq_io_cq
*cic
;
2490 struct cfq_queue
*cfqq
;
2493 * Disallow merge of a sync bio into an async request.
2495 if (cfq_bio_sync(bio
) && !rq_is_sync(rq
))
2499 * Lookup the cfqq that this bio will be queued with and allow
2500 * merge only if rq is queued there.
2502 cic
= cfq_cic_lookup(cfqd
, current
->io_context
);
2506 cfqq
= cic_to_cfqq(cic
, cfq_bio_sync(bio
));
2507 return cfqq
== RQ_CFQQ(rq
);
2510 static inline void cfq_del_timer(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
2512 del_timer(&cfqd
->idle_slice_timer
);
2513 cfqg_stats_update_idle_time(cfqq
->cfqg
);
2516 static void __cfq_set_active_queue(struct cfq_data
*cfqd
,
2517 struct cfq_queue
*cfqq
)
2520 cfq_log_cfqq(cfqd
, cfqq
, "set_active wl_class:%d wl_type:%d",
2521 cfqd
->serving_wl_class
, cfqd
->serving_wl_type
);
2522 cfqg_stats_update_avg_queue_size(cfqq
->cfqg
);
2523 cfqq
->slice_start
= 0;
2524 cfqq
->dispatch_start
= jiffies
;
2525 cfqq
->allocated_slice
= 0;
2526 cfqq
->slice_end
= 0;
2527 cfqq
->slice_dispatch
= 0;
2528 cfqq
->nr_sectors
= 0;
2530 cfq_clear_cfqq_wait_request(cfqq
);
2531 cfq_clear_cfqq_must_dispatch(cfqq
);
2532 cfq_clear_cfqq_must_alloc_slice(cfqq
);
2533 cfq_clear_cfqq_fifo_expire(cfqq
);
2534 cfq_mark_cfqq_slice_new(cfqq
);
2536 cfq_del_timer(cfqd
, cfqq
);
2539 cfqd
->active_queue
= cfqq
;
2543 * current cfqq expired its slice (or was too idle), select new one
2546 __cfq_slice_expired(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
2549 cfq_log_cfqq(cfqd
, cfqq
, "slice expired t=%d", timed_out
);
2551 if (cfq_cfqq_wait_request(cfqq
))
2552 cfq_del_timer(cfqd
, cfqq
);
2554 cfq_clear_cfqq_wait_request(cfqq
);
2555 cfq_clear_cfqq_wait_busy(cfqq
);
2558 * If this cfqq is shared between multiple processes, check to
2559 * make sure that those processes are still issuing I/Os within
2560 * the mean seek distance. If not, it may be time to break the
2561 * queues apart again.
2563 if (cfq_cfqq_coop(cfqq
) && CFQQ_SEEKY(cfqq
))
2564 cfq_mark_cfqq_split_coop(cfqq
);
2567 * store what was left of this slice, if the queue idled/timed out
2570 if (cfq_cfqq_slice_new(cfqq
))
2571 cfqq
->slice_resid
= cfq_scaled_cfqq_slice(cfqd
, cfqq
);
2573 cfqq
->slice_resid
= cfqq
->slice_end
- jiffies
;
2574 cfq_log_cfqq(cfqd
, cfqq
, "resid=%ld", cfqq
->slice_resid
);
2577 cfq_group_served(cfqd
, cfqq
->cfqg
, cfqq
);
2579 if (cfq_cfqq_on_rr(cfqq
) && RB_EMPTY_ROOT(&cfqq
->sort_list
))
2580 cfq_del_cfqq_rr(cfqd
, cfqq
);
2582 cfq_resort_rr_list(cfqd
, cfqq
);
2584 if (cfqq
== cfqd
->active_queue
)
2585 cfqd
->active_queue
= NULL
;
2587 if (cfqd
->active_cic
) {
2588 put_io_context(cfqd
->active_cic
->icq
.ioc
);
2589 cfqd
->active_cic
= NULL
;
2593 static inline void cfq_slice_expired(struct cfq_data
*cfqd
, bool timed_out
)
2595 struct cfq_queue
*cfqq
= cfqd
->active_queue
;
2598 __cfq_slice_expired(cfqd
, cfqq
, timed_out
);
2602 * Get next queue for service. Unless we have a queue preemption,
2603 * we'll simply select the first cfqq in the service tree.
2605 static struct cfq_queue
*cfq_get_next_queue(struct cfq_data
*cfqd
)
2607 struct cfq_rb_root
*st
= st_for(cfqd
->serving_group
,
2608 cfqd
->serving_wl_class
, cfqd
->serving_wl_type
);
2610 if (!cfqd
->rq_queued
)
2613 /* There is nothing to dispatch */
2616 if (RB_EMPTY_ROOT(&st
->rb
))
2618 return cfq_rb_first(st
);
2621 static struct cfq_queue
*cfq_get_next_queue_forced(struct cfq_data
*cfqd
)
2623 struct cfq_group
*cfqg
;
2624 struct cfq_queue
*cfqq
;
2626 struct cfq_rb_root
*st
;
2628 if (!cfqd
->rq_queued
)
2631 cfqg
= cfq_get_next_cfqg(cfqd
);
2635 for_each_cfqg_st(cfqg
, i
, j
, st
)
2636 if ((cfqq
= cfq_rb_first(st
)) != NULL
)
2642 * Get and set a new active queue for service.
2644 static struct cfq_queue
*cfq_set_active_queue(struct cfq_data
*cfqd
,
2645 struct cfq_queue
*cfqq
)
2648 cfqq
= cfq_get_next_queue(cfqd
);
2650 __cfq_set_active_queue(cfqd
, cfqq
);
2654 static inline sector_t
cfq_dist_from_last(struct cfq_data
*cfqd
,
2657 if (blk_rq_pos(rq
) >= cfqd
->last_position
)
2658 return blk_rq_pos(rq
) - cfqd
->last_position
;
2660 return cfqd
->last_position
- blk_rq_pos(rq
);
2663 static inline int cfq_rq_close(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
2666 return cfq_dist_from_last(cfqd
, rq
) <= CFQQ_CLOSE_THR
;
2669 static struct cfq_queue
*cfqq_close(struct cfq_data
*cfqd
,
2670 struct cfq_queue
*cur_cfqq
)
2672 struct rb_root
*root
= &cfqd
->prio_trees
[cur_cfqq
->org_ioprio
];
2673 struct rb_node
*parent
, *node
;
2674 struct cfq_queue
*__cfqq
;
2675 sector_t sector
= cfqd
->last_position
;
2677 if (RB_EMPTY_ROOT(root
))
2681 * First, if we find a request starting at the end of the last
2682 * request, choose it.
2684 __cfqq
= cfq_prio_tree_lookup(cfqd
, root
, sector
, &parent
, NULL
);
2689 * If the exact sector wasn't found, the parent of the NULL leaf
2690 * will contain the closest sector.
2692 __cfqq
= rb_entry(parent
, struct cfq_queue
, p_node
);
2693 if (cfq_rq_close(cfqd
, cur_cfqq
, __cfqq
->next_rq
))
2696 if (blk_rq_pos(__cfqq
->next_rq
) < sector
)
2697 node
= rb_next(&__cfqq
->p_node
);
2699 node
= rb_prev(&__cfqq
->p_node
);
2703 __cfqq
= rb_entry(node
, struct cfq_queue
, p_node
);
2704 if (cfq_rq_close(cfqd
, cur_cfqq
, __cfqq
->next_rq
))
2712 * cur_cfqq - passed in so that we don't decide that the current queue is
2713 * closely cooperating with itself.
2715 * So, basically we're assuming that that cur_cfqq has dispatched at least
2716 * one request, and that cfqd->last_position reflects a position on the disk
2717 * associated with the I/O issued by cur_cfqq. I'm not sure this is a valid
2720 static struct cfq_queue
*cfq_close_cooperator(struct cfq_data
*cfqd
,
2721 struct cfq_queue
*cur_cfqq
)
2723 struct cfq_queue
*cfqq
;
2725 if (cfq_class_idle(cur_cfqq
))
2727 if (!cfq_cfqq_sync(cur_cfqq
))
2729 if (CFQQ_SEEKY(cur_cfqq
))
2733 * Don't search priority tree if it's the only queue in the group.
2735 if (cur_cfqq
->cfqg
->nr_cfqq
== 1)
2739 * We should notice if some of the queues are cooperating, eg
2740 * working closely on the same area of the disk. In that case,
2741 * we can group them together and don't waste time idling.
2743 cfqq
= cfqq_close(cfqd
, cur_cfqq
);
2747 /* If new queue belongs to different cfq_group, don't choose it */
2748 if (cur_cfqq
->cfqg
!= cfqq
->cfqg
)
2752 * It only makes sense to merge sync queues.
2754 if (!cfq_cfqq_sync(cfqq
))
2756 if (CFQQ_SEEKY(cfqq
))
2760 * Do not merge queues of different priority classes
2762 if (cfq_class_rt(cfqq
) != cfq_class_rt(cur_cfqq
))
2769 * Determine whether we should enforce idle window for this queue.
2772 static bool cfq_should_idle(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
2774 enum wl_class_t wl_class
= cfqq_class(cfqq
);
2775 struct cfq_rb_root
*st
= cfqq
->service_tree
;
2780 if (!cfqd
->cfq_slice_idle
)
2783 /* We never do for idle class queues. */
2784 if (wl_class
== IDLE_WORKLOAD
)
2787 /* We do for queues that were marked with idle window flag. */
2788 if (cfq_cfqq_idle_window(cfqq
) &&
2789 !(blk_queue_nonrot(cfqd
->queue
) && cfqd
->hw_tag
))
2793 * Otherwise, we do only if they are the last ones
2794 * in their service tree.
2796 if (st
->count
== 1 && cfq_cfqq_sync(cfqq
) &&
2797 !cfq_io_thinktime_big(cfqd
, &st
->ttime
, false))
2799 cfq_log_cfqq(cfqd
, cfqq
, "Not idling. st->count:%d", st
->count
);
2803 static void cfq_arm_slice_timer(struct cfq_data
*cfqd
)
2805 struct cfq_queue
*cfqq
= cfqd
->active_queue
;
2806 struct cfq_io_cq
*cic
;
2807 unsigned long sl
, group_idle
= 0;
2810 * SSD device without seek penalty, disable idling. But only do so
2811 * for devices that support queuing, otherwise we still have a problem
2812 * with sync vs async workloads.
2814 if (blk_queue_nonrot(cfqd
->queue
) && cfqd
->hw_tag
)
2817 WARN_ON(!RB_EMPTY_ROOT(&cfqq
->sort_list
));
2818 WARN_ON(cfq_cfqq_slice_new(cfqq
));
2821 * idle is disabled, either manually or by past process history
2823 if (!cfq_should_idle(cfqd
, cfqq
)) {
2824 /* no queue idling. Check for group idling */
2825 if (cfqd
->cfq_group_idle
)
2826 group_idle
= cfqd
->cfq_group_idle
;
2832 * still active requests from this queue, don't idle
2834 if (cfqq
->dispatched
)
2838 * task has exited, don't wait
2840 cic
= cfqd
->active_cic
;
2841 if (!cic
|| !atomic_read(&cic
->icq
.ioc
->active_ref
))
2845 * If our average think time is larger than the remaining time
2846 * slice, then don't idle. This avoids overrunning the allotted
2849 if (sample_valid(cic
->ttime
.ttime_samples
) &&
2850 (cfqq
->slice_end
- jiffies
< cic
->ttime
.ttime_mean
)) {
2851 cfq_log_cfqq(cfqd
, cfqq
, "Not idling. think_time:%lu",
2852 cic
->ttime
.ttime_mean
);
2856 /* There are other queues in the group, don't do group idle */
2857 if (group_idle
&& cfqq
->cfqg
->nr_cfqq
> 1)
2860 cfq_mark_cfqq_wait_request(cfqq
);
2863 sl
= cfqd
->cfq_group_idle
;
2865 sl
= cfqd
->cfq_slice_idle
;
2867 mod_timer(&cfqd
->idle_slice_timer
, jiffies
+ sl
);
2868 cfqg_stats_set_start_idle_time(cfqq
->cfqg
);
2869 cfq_log_cfqq(cfqd
, cfqq
, "arm_idle: %lu group_idle: %d", sl
,
2870 group_idle
? 1 : 0);
2874 * Move request from internal lists to the request queue dispatch list.
2876 static void cfq_dispatch_insert(struct request_queue
*q
, struct request
*rq
)
2878 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
2879 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
2881 cfq_log_cfqq(cfqd
, cfqq
, "dispatch_insert");
2883 cfqq
->next_rq
= cfq_find_next_rq(cfqd
, cfqq
, rq
);
2884 cfq_remove_request(rq
);
2886 (RQ_CFQG(rq
))->dispatched
++;
2887 elv_dispatch_sort(q
, rq
);
2889 cfqd
->rq_in_flight
[cfq_cfqq_sync(cfqq
)]++;
2890 cfqq
->nr_sectors
+= blk_rq_sectors(rq
);
2891 cfqg_stats_update_dispatch(cfqq
->cfqg
, blk_rq_bytes(rq
), rq
->cmd_flags
);
2895 * return expired entry, or NULL to just start from scratch in rbtree
2897 static struct request
*cfq_check_fifo(struct cfq_queue
*cfqq
)
2899 struct request
*rq
= NULL
;
2901 if (cfq_cfqq_fifo_expire(cfqq
))
2904 cfq_mark_cfqq_fifo_expire(cfqq
);
2906 if (list_empty(&cfqq
->fifo
))
2909 rq
= rq_entry_fifo(cfqq
->fifo
.next
);
2910 if (time_before(jiffies
, rq
->fifo_time
))
2913 cfq_log_cfqq(cfqq
->cfqd
, cfqq
, "fifo=%p", rq
);
2918 cfq_prio_to_maxrq(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
2920 const int base_rq
= cfqd
->cfq_slice_async_rq
;
2922 WARN_ON(cfqq
->ioprio
>= IOPRIO_BE_NR
);
2924 return 2 * base_rq
* (IOPRIO_BE_NR
- cfqq
->ioprio
);
2928 * Must be called with the queue_lock held.
2930 static int cfqq_process_refs(struct cfq_queue
*cfqq
)
2932 int process_refs
, io_refs
;
2934 io_refs
= cfqq
->allocated
[READ
] + cfqq
->allocated
[WRITE
];
2935 process_refs
= cfqq
->ref
- io_refs
;
2936 BUG_ON(process_refs
< 0);
2937 return process_refs
;
2940 static void cfq_setup_merge(struct cfq_queue
*cfqq
, struct cfq_queue
*new_cfqq
)
2942 int process_refs
, new_process_refs
;
2943 struct cfq_queue
*__cfqq
;
2946 * If there are no process references on the new_cfqq, then it is
2947 * unsafe to follow the ->new_cfqq chain as other cfqq's in the
2948 * chain may have dropped their last reference (not just their
2949 * last process reference).
2951 if (!cfqq_process_refs(new_cfqq
))
2954 /* Avoid a circular list and skip interim queue merges */
2955 while ((__cfqq
= new_cfqq
->new_cfqq
)) {
2961 process_refs
= cfqq_process_refs(cfqq
);
2962 new_process_refs
= cfqq_process_refs(new_cfqq
);
2964 * If the process for the cfqq has gone away, there is no
2965 * sense in merging the queues.
2967 if (process_refs
== 0 || new_process_refs
== 0)
2971 * Merge in the direction of the lesser amount of work.
2973 if (new_process_refs
>= process_refs
) {
2974 cfqq
->new_cfqq
= new_cfqq
;
2975 new_cfqq
->ref
+= process_refs
;
2977 new_cfqq
->new_cfqq
= cfqq
;
2978 cfqq
->ref
+= new_process_refs
;
2982 static enum wl_type_t
cfq_choose_wl_type(struct cfq_data
*cfqd
,
2983 struct cfq_group
*cfqg
, enum wl_class_t wl_class
)
2985 struct cfq_queue
*queue
;
2987 bool key_valid
= false;
2988 unsigned long lowest_key
= 0;
2989 enum wl_type_t cur_best
= SYNC_NOIDLE_WORKLOAD
;
2991 for (i
= 0; i
<= SYNC_WORKLOAD
; ++i
) {
2992 /* select the one with lowest rb_key */
2993 queue
= cfq_rb_first(st_for(cfqg
, wl_class
, i
));
2995 (!key_valid
|| time_before(queue
->rb_key
, lowest_key
))) {
2996 lowest_key
= queue
->rb_key
;
3006 choose_wl_class_and_type(struct cfq_data
*cfqd
, struct cfq_group
*cfqg
)
3010 struct cfq_rb_root
*st
;
3011 unsigned group_slice
;
3012 enum wl_class_t original_class
= cfqd
->serving_wl_class
;
3014 /* Choose next priority. RT > BE > IDLE */
3015 if (cfq_group_busy_queues_wl(RT_WORKLOAD
, cfqd
, cfqg
))
3016 cfqd
->serving_wl_class
= RT_WORKLOAD
;
3017 else if (cfq_group_busy_queues_wl(BE_WORKLOAD
, cfqd
, cfqg
))
3018 cfqd
->serving_wl_class
= BE_WORKLOAD
;
3020 cfqd
->serving_wl_class
= IDLE_WORKLOAD
;
3021 cfqd
->workload_expires
= jiffies
+ 1;
3025 if (original_class
!= cfqd
->serving_wl_class
)
3029 * For RT and BE, we have to choose also the type
3030 * (SYNC, SYNC_NOIDLE, ASYNC), and to compute a workload
3033 st
= st_for(cfqg
, cfqd
->serving_wl_class
, cfqd
->serving_wl_type
);
3037 * check workload expiration, and that we still have other queues ready
3039 if (count
&& !time_after(jiffies
, cfqd
->workload_expires
))
3043 /* otherwise select new workload type */
3044 cfqd
->serving_wl_type
= cfq_choose_wl_type(cfqd
, cfqg
,
3045 cfqd
->serving_wl_class
);
3046 st
= st_for(cfqg
, cfqd
->serving_wl_class
, cfqd
->serving_wl_type
);
3050 * the workload slice is computed as a fraction of target latency
3051 * proportional to the number of queues in that workload, over
3052 * all the queues in the same priority class
3054 group_slice
= cfq_group_slice(cfqd
, cfqg
);
3056 slice
= group_slice
* count
/
3057 max_t(unsigned, cfqg
->busy_queues_avg
[cfqd
->serving_wl_class
],
3058 cfq_group_busy_queues_wl(cfqd
->serving_wl_class
, cfqd
,
3061 if (cfqd
->serving_wl_type
== ASYNC_WORKLOAD
) {
3065 * Async queues are currently system wide. Just taking
3066 * proportion of queues with-in same group will lead to higher
3067 * async ratio system wide as generally root group is going
3068 * to have higher weight. A more accurate thing would be to
3069 * calculate system wide asnc/sync ratio.
3071 tmp
= cfqd
->cfq_target_latency
*
3072 cfqg_busy_async_queues(cfqd
, cfqg
);
3073 tmp
= tmp
/cfqd
->busy_queues
;
3074 slice
= min_t(unsigned, slice
, tmp
);
3076 /* async workload slice is scaled down according to
3077 * the sync/async slice ratio. */
3078 slice
= slice
* cfqd
->cfq_slice
[0] / cfqd
->cfq_slice
[1];
3080 /* sync workload slice is at least 2 * cfq_slice_idle */
3081 slice
= max(slice
, 2 * cfqd
->cfq_slice_idle
);
3083 slice
= max_t(unsigned, slice
, CFQ_MIN_TT
);
3084 cfq_log(cfqd
, "workload slice:%d", slice
);
3085 cfqd
->workload_expires
= jiffies
+ slice
;
3088 static struct cfq_group
*cfq_get_next_cfqg(struct cfq_data
*cfqd
)
3090 struct cfq_rb_root
*st
= &cfqd
->grp_service_tree
;
3091 struct cfq_group
*cfqg
;
3093 if (RB_EMPTY_ROOT(&st
->rb
))
3095 cfqg
= cfq_rb_first_group(st
);
3096 update_min_vdisktime(st
);
3100 static void cfq_choose_cfqg(struct cfq_data
*cfqd
)
3102 struct cfq_group
*cfqg
= cfq_get_next_cfqg(cfqd
);
3104 cfqd
->serving_group
= cfqg
;
3106 /* Restore the workload type data */
3107 if (cfqg
->saved_wl_slice
) {
3108 cfqd
->workload_expires
= jiffies
+ cfqg
->saved_wl_slice
;
3109 cfqd
->serving_wl_type
= cfqg
->saved_wl_type
;
3110 cfqd
->serving_wl_class
= cfqg
->saved_wl_class
;
3112 cfqd
->workload_expires
= jiffies
- 1;
3114 choose_wl_class_and_type(cfqd
, cfqg
);
3118 * Select a queue for service. If we have a current active queue,
3119 * check whether to continue servicing it, or retrieve and set a new one.
3121 static struct cfq_queue
*cfq_select_queue(struct cfq_data
*cfqd
)
3123 struct cfq_queue
*cfqq
, *new_cfqq
= NULL
;
3125 cfqq
= cfqd
->active_queue
;
3129 if (!cfqd
->rq_queued
)
3133 * We were waiting for group to get backlogged. Expire the queue
3135 if (cfq_cfqq_wait_busy(cfqq
) && !RB_EMPTY_ROOT(&cfqq
->sort_list
))
3139 * The active queue has run out of time, expire it and select new.
3141 if (cfq_slice_used(cfqq
) && !cfq_cfqq_must_dispatch(cfqq
)) {
3143 * If slice had not expired at the completion of last request
3144 * we might not have turned on wait_busy flag. Don't expire
3145 * the queue yet. Allow the group to get backlogged.
3147 * The very fact that we have used the slice, that means we
3148 * have been idling all along on this queue and it should be
3149 * ok to wait for this request to complete.
3151 if (cfqq
->cfqg
->nr_cfqq
== 1 && RB_EMPTY_ROOT(&cfqq
->sort_list
)
3152 && cfqq
->dispatched
&& cfq_should_idle(cfqd
, cfqq
)) {
3156 goto check_group_idle
;
3160 * The active queue has requests and isn't expired, allow it to
3163 if (!RB_EMPTY_ROOT(&cfqq
->sort_list
))
3167 * If another queue has a request waiting within our mean seek
3168 * distance, let it run. The expire code will check for close
3169 * cooperators and put the close queue at the front of the service
3170 * tree. If possible, merge the expiring queue with the new cfqq.
3172 new_cfqq
= cfq_close_cooperator(cfqd
, cfqq
);
3174 if (!cfqq
->new_cfqq
)
3175 cfq_setup_merge(cfqq
, new_cfqq
);
3180 * No requests pending. If the active queue still has requests in
3181 * flight or is idling for a new request, allow either of these
3182 * conditions to happen (or time out) before selecting a new queue.
3184 if (timer_pending(&cfqd
->idle_slice_timer
)) {
3190 * This is a deep seek queue, but the device is much faster than
3191 * the queue can deliver, don't idle
3193 if (CFQQ_SEEKY(cfqq
) && cfq_cfqq_idle_window(cfqq
) &&
3194 (cfq_cfqq_slice_new(cfqq
) ||
3195 (cfqq
->slice_end
- jiffies
> jiffies
- cfqq
->slice_start
))) {
3196 cfq_clear_cfqq_deep(cfqq
);
3197 cfq_clear_cfqq_idle_window(cfqq
);
3200 if (cfqq
->dispatched
&& cfq_should_idle(cfqd
, cfqq
)) {
3206 * If group idle is enabled and there are requests dispatched from
3207 * this group, wait for requests to complete.
3210 if (cfqd
->cfq_group_idle
&& cfqq
->cfqg
->nr_cfqq
== 1 &&
3211 cfqq
->cfqg
->dispatched
&&
3212 !cfq_io_thinktime_big(cfqd
, &cfqq
->cfqg
->ttime
, true)) {
3218 cfq_slice_expired(cfqd
, 0);
3221 * Current queue expired. Check if we have to switch to a new
3225 cfq_choose_cfqg(cfqd
);
3227 cfqq
= cfq_set_active_queue(cfqd
, new_cfqq
);
3232 static int __cfq_forced_dispatch_cfqq(struct cfq_queue
*cfqq
)
3236 while (cfqq
->next_rq
) {
3237 cfq_dispatch_insert(cfqq
->cfqd
->queue
, cfqq
->next_rq
);
3241 BUG_ON(!list_empty(&cfqq
->fifo
));
3243 /* By default cfqq is not expired if it is empty. Do it explicitly */
3244 __cfq_slice_expired(cfqq
->cfqd
, cfqq
, 0);
3249 * Drain our current requests. Used for barriers and when switching
3250 * io schedulers on-the-fly.
3252 static int cfq_forced_dispatch(struct cfq_data
*cfqd
)
3254 struct cfq_queue
*cfqq
;
3257 /* Expire the timeslice of the current active queue first */
3258 cfq_slice_expired(cfqd
, 0);
3259 while ((cfqq
= cfq_get_next_queue_forced(cfqd
)) != NULL
) {
3260 __cfq_set_active_queue(cfqd
, cfqq
);
3261 dispatched
+= __cfq_forced_dispatch_cfqq(cfqq
);
3264 BUG_ON(cfqd
->busy_queues
);
3266 cfq_log(cfqd
, "forced_dispatch=%d", dispatched
);
3270 static inline bool cfq_slice_used_soon(struct cfq_data
*cfqd
,
3271 struct cfq_queue
*cfqq
)
3273 /* the queue hasn't finished any request, can't estimate */
3274 if (cfq_cfqq_slice_new(cfqq
))
3276 if (time_after(jiffies
+ cfqd
->cfq_slice_idle
* cfqq
->dispatched
,
3283 static bool cfq_may_dispatch(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
3285 unsigned int max_dispatch
;
3288 * Drain async requests before we start sync IO
3290 if (cfq_should_idle(cfqd
, cfqq
) && cfqd
->rq_in_flight
[BLK_RW_ASYNC
])
3294 * If this is an async queue and we have sync IO in flight, let it wait
3296 if (cfqd
->rq_in_flight
[BLK_RW_SYNC
] && !cfq_cfqq_sync(cfqq
))
3299 max_dispatch
= max_t(unsigned int, cfqd
->cfq_quantum
/ 2, 1);
3300 if (cfq_class_idle(cfqq
))
3304 * Does this cfqq already have too much IO in flight?
3306 if (cfqq
->dispatched
>= max_dispatch
) {
3307 bool promote_sync
= false;
3309 * idle queue must always only have a single IO in flight
3311 if (cfq_class_idle(cfqq
))
3315 * If there is only one sync queue
3316 * we can ignore async queue here and give the sync
3317 * queue no dispatch limit. The reason is a sync queue can
3318 * preempt async queue, limiting the sync queue doesn't make
3319 * sense. This is useful for aiostress test.
3321 if (cfq_cfqq_sync(cfqq
) && cfqd
->busy_sync_queues
== 1)
3322 promote_sync
= true;
3325 * We have other queues, don't allow more IO from this one
3327 if (cfqd
->busy_queues
> 1 && cfq_slice_used_soon(cfqd
, cfqq
) &&
3332 * Sole queue user, no limit
3334 if (cfqd
->busy_queues
== 1 || promote_sync
)
3338 * Normally we start throttling cfqq when cfq_quantum/2
3339 * requests have been dispatched. But we can drive
3340 * deeper queue depths at the beginning of slice
3341 * subjected to upper limit of cfq_quantum.
3343 max_dispatch
= cfqd
->cfq_quantum
;
3347 * Async queues must wait a bit before being allowed dispatch.
3348 * We also ramp up the dispatch depth gradually for async IO,
3349 * based on the last sync IO we serviced
3351 if (!cfq_cfqq_sync(cfqq
) && cfqd
->cfq_latency
) {
3352 unsigned long last_sync
= jiffies
- cfqd
->last_delayed_sync
;
3355 depth
= last_sync
/ cfqd
->cfq_slice
[1];
3356 if (!depth
&& !cfqq
->dispatched
)
3358 if (depth
< max_dispatch
)
3359 max_dispatch
= depth
;
3363 * If we're below the current max, allow a dispatch
3365 return cfqq
->dispatched
< max_dispatch
;
3369 * Dispatch a request from cfqq, moving them to the request queue
3372 static bool cfq_dispatch_request(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
3376 BUG_ON(RB_EMPTY_ROOT(&cfqq
->sort_list
));
3378 if (!cfq_may_dispatch(cfqd
, cfqq
))
3382 * follow expired path, else get first next available
3384 rq
= cfq_check_fifo(cfqq
);
3389 * insert request into driver dispatch list
3391 cfq_dispatch_insert(cfqd
->queue
, rq
);
3393 if (!cfqd
->active_cic
) {
3394 struct cfq_io_cq
*cic
= RQ_CIC(rq
);
3396 atomic_long_inc(&cic
->icq
.ioc
->refcount
);
3397 cfqd
->active_cic
= cic
;
3404 * Find the cfqq that we need to service and move a request from that to the
3407 static int cfq_dispatch_requests(struct request_queue
*q
, int force
)
3409 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
3410 struct cfq_queue
*cfqq
;
3412 if (!cfqd
->busy_queues
)
3415 if (unlikely(force
))
3416 return cfq_forced_dispatch(cfqd
);
3418 cfqq
= cfq_select_queue(cfqd
);
3423 * Dispatch a request from this cfqq, if it is allowed
3425 if (!cfq_dispatch_request(cfqd
, cfqq
))
3428 cfqq
->slice_dispatch
++;
3429 cfq_clear_cfqq_must_dispatch(cfqq
);
3432 * expire an async queue immediately if it has used up its slice. idle
3433 * queue always expire after 1 dispatch round.
3435 if (cfqd
->busy_queues
> 1 && ((!cfq_cfqq_sync(cfqq
) &&
3436 cfqq
->slice_dispatch
>= cfq_prio_to_maxrq(cfqd
, cfqq
)) ||
3437 cfq_class_idle(cfqq
))) {
3438 cfqq
->slice_end
= jiffies
+ 1;
3439 cfq_slice_expired(cfqd
, 0);
3442 cfq_log_cfqq(cfqd
, cfqq
, "dispatched a request");
3447 * task holds one reference to the queue, dropped when task exits. each rq
3448 * in-flight on this queue also holds a reference, dropped when rq is freed.
3450 * Each cfq queue took a reference on the parent group. Drop it now.
3451 * queue lock must be held here.
3453 static void cfq_put_queue(struct cfq_queue
*cfqq
)
3455 struct cfq_data
*cfqd
= cfqq
->cfqd
;
3456 struct cfq_group
*cfqg
;
3458 BUG_ON(cfqq
->ref
<= 0);
3464 cfq_log_cfqq(cfqd
, cfqq
, "put_queue");
3465 BUG_ON(rb_first(&cfqq
->sort_list
));
3466 BUG_ON(cfqq
->allocated
[READ
] + cfqq
->allocated
[WRITE
]);
3469 if (unlikely(cfqd
->active_queue
== cfqq
)) {
3470 __cfq_slice_expired(cfqd
, cfqq
, 0);
3471 cfq_schedule_dispatch(cfqd
);
3474 BUG_ON(cfq_cfqq_on_rr(cfqq
));
3475 kmem_cache_free(cfq_pool
, cfqq
);
3479 static void cfq_put_cooperator(struct cfq_queue
*cfqq
)
3481 struct cfq_queue
*__cfqq
, *next
;
3484 * If this queue was scheduled to merge with another queue, be
3485 * sure to drop the reference taken on that queue (and others in
3486 * the merge chain). See cfq_setup_merge and cfq_merge_cfqqs.
3488 __cfqq
= cfqq
->new_cfqq
;
3490 if (__cfqq
== cfqq
) {
3491 WARN(1, "cfqq->new_cfqq loop detected\n");
3494 next
= __cfqq
->new_cfqq
;
3495 cfq_put_queue(__cfqq
);
3500 static void cfq_exit_cfqq(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
3502 if (unlikely(cfqq
== cfqd
->active_queue
)) {
3503 __cfq_slice_expired(cfqd
, cfqq
, 0);
3504 cfq_schedule_dispatch(cfqd
);
3507 cfq_put_cooperator(cfqq
);
3509 cfq_put_queue(cfqq
);
3512 static void cfq_init_icq(struct io_cq
*icq
)
3514 struct cfq_io_cq
*cic
= icq_to_cic(icq
);
3516 cic
->ttime
.last_end_request
= jiffies
;
3519 static void cfq_exit_icq(struct io_cq
*icq
)
3521 struct cfq_io_cq
*cic
= icq_to_cic(icq
);
3522 struct cfq_data
*cfqd
= cic_to_cfqd(cic
);
3524 if (cic_to_cfqq(cic
, false)) {
3525 cfq_exit_cfqq(cfqd
, cic_to_cfqq(cic
, false));
3526 cic_set_cfqq(cic
, NULL
, false);
3529 if (cic_to_cfqq(cic
, true)) {
3530 cfq_exit_cfqq(cfqd
, cic_to_cfqq(cic
, true));
3531 cic_set_cfqq(cic
, NULL
, true);
3535 static void cfq_init_prio_data(struct cfq_queue
*cfqq
, struct cfq_io_cq
*cic
)
3537 struct task_struct
*tsk
= current
;
3540 if (!cfq_cfqq_prio_changed(cfqq
))
3543 ioprio_class
= IOPRIO_PRIO_CLASS(cic
->ioprio
);
3544 switch (ioprio_class
) {
3546 printk(KERN_ERR
"cfq: bad prio %x\n", ioprio_class
);
3547 case IOPRIO_CLASS_NONE
:
3549 * no prio set, inherit CPU scheduling settings
3551 cfqq
->ioprio
= task_nice_ioprio(tsk
);
3552 cfqq
->ioprio_class
= task_nice_ioclass(tsk
);
3554 case IOPRIO_CLASS_RT
:
3555 cfqq
->ioprio
= IOPRIO_PRIO_DATA(cic
->ioprio
);
3556 cfqq
->ioprio_class
= IOPRIO_CLASS_RT
;
3558 case IOPRIO_CLASS_BE
:
3559 cfqq
->ioprio
= IOPRIO_PRIO_DATA(cic
->ioprio
);
3560 cfqq
->ioprio_class
= IOPRIO_CLASS_BE
;
3562 case IOPRIO_CLASS_IDLE
:
3563 cfqq
->ioprio_class
= IOPRIO_CLASS_IDLE
;
3565 cfq_clear_cfqq_idle_window(cfqq
);
3570 * keep track of original prio settings in case we have to temporarily
3571 * elevate the priority of this queue
3573 cfqq
->org_ioprio
= cfqq
->ioprio
;
3574 cfq_clear_cfqq_prio_changed(cfqq
);
3577 static void check_ioprio_changed(struct cfq_io_cq
*cic
, struct bio
*bio
)
3579 int ioprio
= cic
->icq
.ioc
->ioprio
;
3580 struct cfq_data
*cfqd
= cic_to_cfqd(cic
);
3581 struct cfq_queue
*cfqq
;
3584 * Check whether ioprio has changed. The condition may trigger
3585 * spuriously on a newly created cic but there's no harm.
3587 if (unlikely(!cfqd
) || likely(cic
->ioprio
== ioprio
))
3590 cfqq
= cic_to_cfqq(cic
, false);
3592 cfq_put_queue(cfqq
);
3593 cfqq
= cfq_get_queue(cfqd
, BLK_RW_ASYNC
, cic
, bio
);
3594 cic_set_cfqq(cic
, cfqq
, false);
3597 cfqq
= cic_to_cfqq(cic
, true);
3599 cfq_mark_cfqq_prio_changed(cfqq
);
3601 cic
->ioprio
= ioprio
;
3604 static void cfq_init_cfqq(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
3605 pid_t pid
, bool is_sync
)
3607 RB_CLEAR_NODE(&cfqq
->rb_node
);
3608 RB_CLEAR_NODE(&cfqq
->p_node
);
3609 INIT_LIST_HEAD(&cfqq
->fifo
);
3614 cfq_mark_cfqq_prio_changed(cfqq
);
3617 if (!cfq_class_idle(cfqq
))
3618 cfq_mark_cfqq_idle_window(cfqq
);
3619 cfq_mark_cfqq_sync(cfqq
);
3624 #ifdef CONFIG_CFQ_GROUP_IOSCHED
3625 static void check_blkcg_changed(struct cfq_io_cq
*cic
, struct bio
*bio
)
3627 struct cfq_data
*cfqd
= cic_to_cfqd(cic
);
3628 struct cfq_queue
*cfqq
;
3632 serial_nr
= bio_blkcg(bio
)->css
.serial_nr
;
3636 * Check whether blkcg has changed. The condition may trigger
3637 * spuriously on a newly created cic but there's no harm.
3639 if (unlikely(!cfqd
) || likely(cic
->blkcg_serial_nr
== serial_nr
))
3643 * Drop reference to queues. New queues will be assigned in new
3644 * group upon arrival of fresh requests.
3646 cfqq
= cic_to_cfqq(cic
, false);
3648 cfq_log_cfqq(cfqd
, cfqq
, "changed cgroup");
3649 cic_set_cfqq(cic
, NULL
, false);
3650 cfq_put_queue(cfqq
);
3653 cfqq
= cic_to_cfqq(cic
, true);
3655 cfq_log_cfqq(cfqd
, cfqq
, "changed cgroup");
3656 cic_set_cfqq(cic
, NULL
, true);
3657 cfq_put_queue(cfqq
);
3660 cic
->blkcg_serial_nr
= serial_nr
;
3663 static inline void check_blkcg_changed(struct cfq_io_cq
*cic
, struct bio
*bio
) { }
3664 #endif /* CONFIG_CFQ_GROUP_IOSCHED */
3666 static struct cfq_queue
**
3667 cfq_async_queue_prio(struct cfq_group
*cfqg
, int ioprio_class
, int ioprio
)
3669 switch (ioprio_class
) {
3670 case IOPRIO_CLASS_RT
:
3671 return &cfqg
->async_cfqq
[0][ioprio
];
3672 case IOPRIO_CLASS_NONE
:
3673 ioprio
= IOPRIO_NORM
;
3675 case IOPRIO_CLASS_BE
:
3676 return &cfqg
->async_cfqq
[1][ioprio
];
3677 case IOPRIO_CLASS_IDLE
:
3678 return &cfqg
->async_idle_cfqq
;
3684 static struct cfq_queue
*
3685 cfq_get_queue(struct cfq_data
*cfqd
, bool is_sync
, struct cfq_io_cq
*cic
,
3688 int ioprio_class
= IOPRIO_PRIO_CLASS(cic
->ioprio
);
3689 int ioprio
= IOPRIO_PRIO_DATA(cic
->ioprio
);
3690 struct cfq_queue
**async_cfqq
= NULL
;
3691 struct cfq_queue
*cfqq
;
3692 struct cfq_group
*cfqg
;
3695 cfqg
= cfq_lookup_cfqg(cfqd
, bio_blkcg(bio
));
3697 cfqq
= &cfqd
->oom_cfqq
;
3702 if (!ioprio_valid(cic
->ioprio
)) {
3703 struct task_struct
*tsk
= current
;
3704 ioprio
= task_nice_ioprio(tsk
);
3705 ioprio_class
= task_nice_ioclass(tsk
);
3707 async_cfqq
= cfq_async_queue_prio(cfqg
, ioprio_class
, ioprio
);
3713 cfqq
= kmem_cache_alloc_node(cfq_pool
, GFP_NOWAIT
| __GFP_ZERO
,
3716 cfqq
= &cfqd
->oom_cfqq
;
3720 cfq_init_cfqq(cfqd
, cfqq
, current
->pid
, is_sync
);
3721 cfq_init_prio_data(cfqq
, cic
);
3722 cfq_link_cfqq_cfqg(cfqq
, cfqg
);
3723 cfq_log_cfqq(cfqd
, cfqq
, "alloced");
3726 /* a new async queue is created, pin and remember */
3737 __cfq_update_io_thinktime(struct cfq_ttime
*ttime
, unsigned long slice_idle
)
3739 unsigned long elapsed
= jiffies
- ttime
->last_end_request
;
3740 elapsed
= min(elapsed
, 2UL * slice_idle
);
3742 ttime
->ttime_samples
= (7*ttime
->ttime_samples
+ 256) / 8;
3743 ttime
->ttime_total
= (7*ttime
->ttime_total
+ 256*elapsed
) / 8;
3744 ttime
->ttime_mean
= (ttime
->ttime_total
+ 128) / ttime
->ttime_samples
;
3748 cfq_update_io_thinktime(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
3749 struct cfq_io_cq
*cic
)
3751 if (cfq_cfqq_sync(cfqq
)) {
3752 __cfq_update_io_thinktime(&cic
->ttime
, cfqd
->cfq_slice_idle
);
3753 __cfq_update_io_thinktime(&cfqq
->service_tree
->ttime
,
3754 cfqd
->cfq_slice_idle
);
3756 #ifdef CONFIG_CFQ_GROUP_IOSCHED
3757 __cfq_update_io_thinktime(&cfqq
->cfqg
->ttime
, cfqd
->cfq_group_idle
);
3762 cfq_update_io_seektime(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
3766 sector_t n_sec
= blk_rq_sectors(rq
);
3767 if (cfqq
->last_request_pos
) {
3768 if (cfqq
->last_request_pos
< blk_rq_pos(rq
))
3769 sdist
= blk_rq_pos(rq
) - cfqq
->last_request_pos
;
3771 sdist
= cfqq
->last_request_pos
- blk_rq_pos(rq
);
3774 cfqq
->seek_history
<<= 1;
3775 if (blk_queue_nonrot(cfqd
->queue
))
3776 cfqq
->seek_history
|= (n_sec
< CFQQ_SECT_THR_NONROT
);
3778 cfqq
->seek_history
|= (sdist
> CFQQ_SEEK_THR
);
3782 * Disable idle window if the process thinks too long or seeks so much that
3786 cfq_update_idle_window(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
3787 struct cfq_io_cq
*cic
)
3789 int old_idle
, enable_idle
;
3792 * Don't idle for async or idle io prio class
3794 if (!cfq_cfqq_sync(cfqq
) || cfq_class_idle(cfqq
))
3797 enable_idle
= old_idle
= cfq_cfqq_idle_window(cfqq
);
3799 if (cfqq
->queued
[0] + cfqq
->queued
[1] >= 4)
3800 cfq_mark_cfqq_deep(cfqq
);
3802 if (cfqq
->next_rq
&& (cfqq
->next_rq
->cmd_flags
& REQ_NOIDLE
))
3804 else if (!atomic_read(&cic
->icq
.ioc
->active_ref
) ||
3805 !cfqd
->cfq_slice_idle
||
3806 (!cfq_cfqq_deep(cfqq
) && CFQQ_SEEKY(cfqq
)))
3808 else if (sample_valid(cic
->ttime
.ttime_samples
)) {
3809 if (cic
->ttime
.ttime_mean
> cfqd
->cfq_slice_idle
)
3815 if (old_idle
!= enable_idle
) {
3816 cfq_log_cfqq(cfqd
, cfqq
, "idle=%d", enable_idle
);
3818 cfq_mark_cfqq_idle_window(cfqq
);
3820 cfq_clear_cfqq_idle_window(cfqq
);
3825 * Check if new_cfqq should preempt the currently active queue. Return 0 for
3826 * no or if we aren't sure, a 1 will cause a preempt.
3829 cfq_should_preempt(struct cfq_data
*cfqd
, struct cfq_queue
*new_cfqq
,
3832 struct cfq_queue
*cfqq
;
3834 cfqq
= cfqd
->active_queue
;
3838 if (cfq_class_idle(new_cfqq
))
3841 if (cfq_class_idle(cfqq
))
3845 * Don't allow a non-RT request to preempt an ongoing RT cfqq timeslice.
3847 if (cfq_class_rt(cfqq
) && !cfq_class_rt(new_cfqq
))
3851 * if the new request is sync, but the currently running queue is
3852 * not, let the sync request have priority.
3854 if (rq_is_sync(rq
) && !cfq_cfqq_sync(cfqq
))
3857 if (new_cfqq
->cfqg
!= cfqq
->cfqg
)
3860 if (cfq_slice_used(cfqq
))
3863 /* Allow preemption only if we are idling on sync-noidle tree */
3864 if (cfqd
->serving_wl_type
== SYNC_NOIDLE_WORKLOAD
&&
3865 cfqq_type(new_cfqq
) == SYNC_NOIDLE_WORKLOAD
&&
3866 new_cfqq
->service_tree
->count
== 2 &&
3867 RB_EMPTY_ROOT(&cfqq
->sort_list
))
3871 * So both queues are sync. Let the new request get disk time if
3872 * it's a metadata request and the current queue is doing regular IO.
3874 if ((rq
->cmd_flags
& REQ_PRIO
) && !cfqq
->prio_pending
)
3878 * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice.
3880 if (cfq_class_rt(new_cfqq
) && !cfq_class_rt(cfqq
))
3883 /* An idle queue should not be idle now for some reason */
3884 if (RB_EMPTY_ROOT(&cfqq
->sort_list
) && !cfq_should_idle(cfqd
, cfqq
))
3887 if (!cfqd
->active_cic
|| !cfq_cfqq_wait_request(cfqq
))
3891 * if this request is as-good as one we would expect from the
3892 * current cfqq, let it preempt
3894 if (cfq_rq_close(cfqd
, cfqq
, rq
))
3901 * cfqq preempts the active queue. if we allowed preempt with no slice left,
3902 * let it have half of its nominal slice.
3904 static void cfq_preempt_queue(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
3906 enum wl_type_t old_type
= cfqq_type(cfqd
->active_queue
);
3908 cfq_log_cfqq(cfqd
, cfqq
, "preempt");
3909 cfq_slice_expired(cfqd
, 1);
3912 * workload type is changed, don't save slice, otherwise preempt
3915 if (old_type
!= cfqq_type(cfqq
))
3916 cfqq
->cfqg
->saved_wl_slice
= 0;
3919 * Put the new queue at the front of the of the current list,
3920 * so we know that it will be selected next.
3922 BUG_ON(!cfq_cfqq_on_rr(cfqq
));
3924 cfq_service_tree_add(cfqd
, cfqq
, 1);
3926 cfqq
->slice_end
= 0;
3927 cfq_mark_cfqq_slice_new(cfqq
);
3931 * Called when a new fs request (rq) is added (to cfqq). Check if there's
3932 * something we should do about it
3935 cfq_rq_enqueued(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
3938 struct cfq_io_cq
*cic
= RQ_CIC(rq
);
3941 if (rq
->cmd_flags
& REQ_PRIO
)
3942 cfqq
->prio_pending
++;
3944 cfq_update_io_thinktime(cfqd
, cfqq
, cic
);
3945 cfq_update_io_seektime(cfqd
, cfqq
, rq
);
3946 cfq_update_idle_window(cfqd
, cfqq
, cic
);
3948 cfqq
->last_request_pos
= blk_rq_pos(rq
) + blk_rq_sectors(rq
);
3950 if (cfqq
== cfqd
->active_queue
) {
3952 * Remember that we saw a request from this process, but
3953 * don't start queuing just yet. Otherwise we risk seeing lots
3954 * of tiny requests, because we disrupt the normal plugging
3955 * and merging. If the request is already larger than a single
3956 * page, let it rip immediately. For that case we assume that
3957 * merging is already done. Ditto for a busy system that
3958 * has other work pending, don't risk delaying until the
3959 * idle timer unplug to continue working.
3961 if (cfq_cfqq_wait_request(cfqq
)) {
3962 if (blk_rq_bytes(rq
) > PAGE_CACHE_SIZE
||
3963 cfqd
->busy_queues
> 1) {
3964 cfq_del_timer(cfqd
, cfqq
);
3965 cfq_clear_cfqq_wait_request(cfqq
);
3966 __blk_run_queue(cfqd
->queue
);
3968 cfqg_stats_update_idle_time(cfqq
->cfqg
);
3969 cfq_mark_cfqq_must_dispatch(cfqq
);
3972 } else if (cfq_should_preempt(cfqd
, cfqq
, rq
)) {
3974 * not the active queue - expire current slice if it is
3975 * idle and has expired it's mean thinktime or this new queue
3976 * has some old slice time left and is of higher priority or
3977 * this new queue is RT and the current one is BE
3979 cfq_preempt_queue(cfqd
, cfqq
);
3980 __blk_run_queue(cfqd
->queue
);
3984 static void cfq_insert_request(struct request_queue
*q
, struct request
*rq
)
3986 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
3987 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
3989 cfq_log_cfqq(cfqd
, cfqq
, "insert_request");
3990 cfq_init_prio_data(cfqq
, RQ_CIC(rq
));
3992 rq
->fifo_time
= jiffies
+ cfqd
->cfq_fifo_expire
[rq_is_sync(rq
)];
3993 list_add_tail(&rq
->queuelist
, &cfqq
->fifo
);
3995 cfqg_stats_update_io_add(RQ_CFQG(rq
), cfqd
->serving_group
,
3997 cfq_rq_enqueued(cfqd
, cfqq
, rq
);
4001 * Update hw_tag based on peak queue depth over 50 samples under
4004 static void cfq_update_hw_tag(struct cfq_data
*cfqd
)
4006 struct cfq_queue
*cfqq
= cfqd
->active_queue
;
4008 if (cfqd
->rq_in_driver
> cfqd
->hw_tag_est_depth
)
4009 cfqd
->hw_tag_est_depth
= cfqd
->rq_in_driver
;
4011 if (cfqd
->hw_tag
== 1)
4014 if (cfqd
->rq_queued
<= CFQ_HW_QUEUE_MIN
&&
4015 cfqd
->rq_in_driver
<= CFQ_HW_QUEUE_MIN
)
4019 * If active queue hasn't enough requests and can idle, cfq might not
4020 * dispatch sufficient requests to hardware. Don't zero hw_tag in this
4023 if (cfqq
&& cfq_cfqq_idle_window(cfqq
) &&
4024 cfqq
->dispatched
+ cfqq
->queued
[0] + cfqq
->queued
[1] <
4025 CFQ_HW_QUEUE_MIN
&& cfqd
->rq_in_driver
< CFQ_HW_QUEUE_MIN
)
4028 if (cfqd
->hw_tag_samples
++ < 50)
4031 if (cfqd
->hw_tag_est_depth
>= CFQ_HW_QUEUE_MIN
)
4037 static bool cfq_should_wait_busy(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
4039 struct cfq_io_cq
*cic
= cfqd
->active_cic
;
4041 /* If the queue already has requests, don't wait */
4042 if (!RB_EMPTY_ROOT(&cfqq
->sort_list
))
4045 /* If there are other queues in the group, don't wait */
4046 if (cfqq
->cfqg
->nr_cfqq
> 1)
4049 /* the only queue in the group, but think time is big */
4050 if (cfq_io_thinktime_big(cfqd
, &cfqq
->cfqg
->ttime
, true))
4053 if (cfq_slice_used(cfqq
))
4056 /* if slice left is less than think time, wait busy */
4057 if (cic
&& sample_valid(cic
->ttime
.ttime_samples
)
4058 && (cfqq
->slice_end
- jiffies
< cic
->ttime
.ttime_mean
))
4062 * If think times is less than a jiffy than ttime_mean=0 and above
4063 * will not be true. It might happen that slice has not expired yet
4064 * but will expire soon (4-5 ns) during select_queue(). To cover the
4065 * case where think time is less than a jiffy, mark the queue wait
4066 * busy if only 1 jiffy is left in the slice.
4068 if (cfqq
->slice_end
- jiffies
== 1)
4074 static void cfq_completed_request(struct request_queue
*q
, struct request
*rq
)
4076 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
4077 struct cfq_data
*cfqd
= cfqq
->cfqd
;
4078 const int sync
= rq_is_sync(rq
);
4082 cfq_log_cfqq(cfqd
, cfqq
, "complete rqnoidle %d",
4083 !!(rq
->cmd_flags
& REQ_NOIDLE
));
4085 cfq_update_hw_tag(cfqd
);
4087 WARN_ON(!cfqd
->rq_in_driver
);
4088 WARN_ON(!cfqq
->dispatched
);
4089 cfqd
->rq_in_driver
--;
4091 (RQ_CFQG(rq
))->dispatched
--;
4092 cfqg_stats_update_completion(cfqq
->cfqg
, rq_start_time_ns(rq
),
4093 rq_io_start_time_ns(rq
), rq
->cmd_flags
);
4095 cfqd
->rq_in_flight
[cfq_cfqq_sync(cfqq
)]--;
4098 struct cfq_rb_root
*st
;
4100 RQ_CIC(rq
)->ttime
.last_end_request
= now
;
4102 if (cfq_cfqq_on_rr(cfqq
))
4103 st
= cfqq
->service_tree
;
4105 st
= st_for(cfqq
->cfqg
, cfqq_class(cfqq
),
4108 st
->ttime
.last_end_request
= now
;
4109 if (!time_after(rq
->start_time
+ cfqd
->cfq_fifo_expire
[1], now
))
4110 cfqd
->last_delayed_sync
= now
;
4113 #ifdef CONFIG_CFQ_GROUP_IOSCHED
4114 cfqq
->cfqg
->ttime
.last_end_request
= now
;
4118 * If this is the active queue, check if it needs to be expired,
4119 * or if we want to idle in case it has no pending requests.
4121 if (cfqd
->active_queue
== cfqq
) {
4122 const bool cfqq_empty
= RB_EMPTY_ROOT(&cfqq
->sort_list
);
4124 if (cfq_cfqq_slice_new(cfqq
)) {
4125 cfq_set_prio_slice(cfqd
, cfqq
);
4126 cfq_clear_cfqq_slice_new(cfqq
);
4130 * Should we wait for next request to come in before we expire
4133 if (cfq_should_wait_busy(cfqd
, cfqq
)) {
4134 unsigned long extend_sl
= cfqd
->cfq_slice_idle
;
4135 if (!cfqd
->cfq_slice_idle
)
4136 extend_sl
= cfqd
->cfq_group_idle
;
4137 cfqq
->slice_end
= jiffies
+ extend_sl
;
4138 cfq_mark_cfqq_wait_busy(cfqq
);
4139 cfq_log_cfqq(cfqd
, cfqq
, "will busy wait");
4143 * Idling is not enabled on:
4145 * - idle-priority queues
4147 * - queues with still some requests queued
4148 * - when there is a close cooperator
4150 if (cfq_slice_used(cfqq
) || cfq_class_idle(cfqq
))
4151 cfq_slice_expired(cfqd
, 1);
4152 else if (sync
&& cfqq_empty
&&
4153 !cfq_close_cooperator(cfqd
, cfqq
)) {
4154 cfq_arm_slice_timer(cfqd
);
4158 if (!cfqd
->rq_in_driver
)
4159 cfq_schedule_dispatch(cfqd
);
4162 static inline int __cfq_may_queue(struct cfq_queue
*cfqq
)
4164 if (cfq_cfqq_wait_request(cfqq
) && !cfq_cfqq_must_alloc_slice(cfqq
)) {
4165 cfq_mark_cfqq_must_alloc_slice(cfqq
);
4166 return ELV_MQUEUE_MUST
;
4169 return ELV_MQUEUE_MAY
;
4172 static int cfq_may_queue(struct request_queue
*q
, int rw
)
4174 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
4175 struct task_struct
*tsk
= current
;
4176 struct cfq_io_cq
*cic
;
4177 struct cfq_queue
*cfqq
;
4180 * don't force setup of a queue from here, as a call to may_queue
4181 * does not necessarily imply that a request actually will be queued.
4182 * so just lookup a possibly existing queue, or return 'may queue'
4185 cic
= cfq_cic_lookup(cfqd
, tsk
->io_context
);
4187 return ELV_MQUEUE_MAY
;
4189 cfqq
= cic_to_cfqq(cic
, rw_is_sync(rw
));
4191 cfq_init_prio_data(cfqq
, cic
);
4193 return __cfq_may_queue(cfqq
);
4196 return ELV_MQUEUE_MAY
;
4200 * queue lock held here
4202 static void cfq_put_request(struct request
*rq
)
4204 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
4207 const int rw
= rq_data_dir(rq
);
4209 BUG_ON(!cfqq
->allocated
[rw
]);
4210 cfqq
->allocated
[rw
]--;
4212 /* Put down rq reference on cfqg */
4213 cfqg_put(RQ_CFQG(rq
));
4214 rq
->elv
.priv
[0] = NULL
;
4215 rq
->elv
.priv
[1] = NULL
;
4217 cfq_put_queue(cfqq
);
4221 static struct cfq_queue
*
4222 cfq_merge_cfqqs(struct cfq_data
*cfqd
, struct cfq_io_cq
*cic
,
4223 struct cfq_queue
*cfqq
)
4225 cfq_log_cfqq(cfqd
, cfqq
, "merging with queue %p", cfqq
->new_cfqq
);
4226 cic_set_cfqq(cic
, cfqq
->new_cfqq
, 1);
4227 cfq_mark_cfqq_coop(cfqq
->new_cfqq
);
4228 cfq_put_queue(cfqq
);
4229 return cic_to_cfqq(cic
, 1);
4233 * Returns NULL if a new cfqq should be allocated, or the old cfqq if this
4234 * was the last process referring to said cfqq.
4236 static struct cfq_queue
*
4237 split_cfqq(struct cfq_io_cq
*cic
, struct cfq_queue
*cfqq
)
4239 if (cfqq_process_refs(cfqq
) == 1) {
4240 cfqq
->pid
= current
->pid
;
4241 cfq_clear_cfqq_coop(cfqq
);
4242 cfq_clear_cfqq_split_coop(cfqq
);
4246 cic_set_cfqq(cic
, NULL
, 1);
4248 cfq_put_cooperator(cfqq
);
4250 cfq_put_queue(cfqq
);
4254 * Allocate cfq data structures associated with this request.
4257 cfq_set_request(struct request_queue
*q
, struct request
*rq
, struct bio
*bio
,
4260 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
4261 struct cfq_io_cq
*cic
= icq_to_cic(rq
->elv
.icq
);
4262 const int rw
= rq_data_dir(rq
);
4263 const bool is_sync
= rq_is_sync(rq
);
4264 struct cfq_queue
*cfqq
;
4266 spin_lock_irq(q
->queue_lock
);
4268 check_ioprio_changed(cic
, bio
);
4269 check_blkcg_changed(cic
, bio
);
4271 cfqq
= cic_to_cfqq(cic
, is_sync
);
4272 if (!cfqq
|| cfqq
== &cfqd
->oom_cfqq
) {
4274 cfq_put_queue(cfqq
);
4275 cfqq
= cfq_get_queue(cfqd
, is_sync
, cic
, bio
);
4276 cic_set_cfqq(cic
, cfqq
, is_sync
);
4279 * If the queue was seeky for too long, break it apart.
4281 if (cfq_cfqq_coop(cfqq
) && cfq_cfqq_split_coop(cfqq
)) {
4282 cfq_log_cfqq(cfqd
, cfqq
, "breaking apart cfqq");
4283 cfqq
= split_cfqq(cic
, cfqq
);
4289 * Check to see if this queue is scheduled to merge with
4290 * another, closely cooperating queue. The merging of
4291 * queues happens here as it must be done in process context.
4292 * The reference on new_cfqq was taken in merge_cfqqs.
4295 cfqq
= cfq_merge_cfqqs(cfqd
, cic
, cfqq
);
4298 cfqq
->allocated
[rw
]++;
4301 cfqg_get(cfqq
->cfqg
);
4302 rq
->elv
.priv
[0] = cfqq
;
4303 rq
->elv
.priv
[1] = cfqq
->cfqg
;
4304 spin_unlock_irq(q
->queue_lock
);
4308 static void cfq_kick_queue(struct work_struct
*work
)
4310 struct cfq_data
*cfqd
=
4311 container_of(work
, struct cfq_data
, unplug_work
);
4312 struct request_queue
*q
= cfqd
->queue
;
4314 spin_lock_irq(q
->queue_lock
);
4315 __blk_run_queue(cfqd
->queue
);
4316 spin_unlock_irq(q
->queue_lock
);
4320 * Timer running if the active_queue is currently idling inside its time slice
4322 static void cfq_idle_slice_timer(unsigned long data
)
4324 struct cfq_data
*cfqd
= (struct cfq_data
*) data
;
4325 struct cfq_queue
*cfqq
;
4326 unsigned long flags
;
4329 cfq_log(cfqd
, "idle timer fired");
4331 spin_lock_irqsave(cfqd
->queue
->queue_lock
, flags
);
4333 cfqq
= cfqd
->active_queue
;
4338 * We saw a request before the queue expired, let it through
4340 if (cfq_cfqq_must_dispatch(cfqq
))
4346 if (cfq_slice_used(cfqq
))
4350 * only expire and reinvoke request handler, if there are
4351 * other queues with pending requests
4353 if (!cfqd
->busy_queues
)
4357 * not expired and it has a request pending, let it dispatch
4359 if (!RB_EMPTY_ROOT(&cfqq
->sort_list
))
4363 * Queue depth flag is reset only when the idle didn't succeed
4365 cfq_clear_cfqq_deep(cfqq
);
4368 cfq_slice_expired(cfqd
, timed_out
);
4370 cfq_schedule_dispatch(cfqd
);
4372 spin_unlock_irqrestore(cfqd
->queue
->queue_lock
, flags
);
4375 static void cfq_shutdown_timer_wq(struct cfq_data
*cfqd
)
4377 del_timer_sync(&cfqd
->idle_slice_timer
);
4378 cancel_work_sync(&cfqd
->unplug_work
);
4381 static void cfq_exit_queue(struct elevator_queue
*e
)
4383 struct cfq_data
*cfqd
= e
->elevator_data
;
4384 struct request_queue
*q
= cfqd
->queue
;
4386 cfq_shutdown_timer_wq(cfqd
);
4388 spin_lock_irq(q
->queue_lock
);
4390 if (cfqd
->active_queue
)
4391 __cfq_slice_expired(cfqd
, cfqd
->active_queue
, 0);
4393 spin_unlock_irq(q
->queue_lock
);
4395 cfq_shutdown_timer_wq(cfqd
);
4397 #ifdef CONFIG_CFQ_GROUP_IOSCHED
4398 blkcg_deactivate_policy(q
, &blkcg_policy_cfq
);
4400 kfree(cfqd
->root_group
);
4405 static int cfq_init_queue(struct request_queue
*q
, struct elevator_type
*e
)
4407 struct cfq_data
*cfqd
;
4408 struct blkcg_gq
*blkg __maybe_unused
;
4410 struct elevator_queue
*eq
;
4412 eq
= elevator_alloc(q
, e
);
4416 cfqd
= kzalloc_node(sizeof(*cfqd
), GFP_KERNEL
, q
->node
);
4418 kobject_put(&eq
->kobj
);
4421 eq
->elevator_data
= cfqd
;
4424 spin_lock_irq(q
->queue_lock
);
4426 spin_unlock_irq(q
->queue_lock
);
4428 /* Init root service tree */
4429 cfqd
->grp_service_tree
= CFQ_RB_ROOT
;
4431 /* Init root group and prefer root group over other groups by default */
4432 #ifdef CONFIG_CFQ_GROUP_IOSCHED
4433 ret
= blkcg_activate_policy(q
, &blkcg_policy_cfq
);
4437 cfqd
->root_group
= blkg_to_cfqg(q
->root_blkg
);
4440 cfqd
->root_group
= kzalloc_node(sizeof(*cfqd
->root_group
),
4441 GFP_KERNEL
, cfqd
->queue
->node
);
4442 if (!cfqd
->root_group
)
4445 cfq_init_cfqg_base(cfqd
->root_group
);
4447 cfqd
->root_group
->weight
= 2 * CFQ_WEIGHT_DEFAULT
;
4448 cfqd
->root_group
->leaf_weight
= 2 * CFQ_WEIGHT_DEFAULT
;
4451 * Not strictly needed (since RB_ROOT just clears the node and we
4452 * zeroed cfqd on alloc), but better be safe in case someone decides
4453 * to add magic to the rb code
4455 for (i
= 0; i
< CFQ_PRIO_LISTS
; i
++)
4456 cfqd
->prio_trees
[i
] = RB_ROOT
;
4459 * Our fallback cfqq if cfq_get_queue() runs into OOM issues.
4460 * Grab a permanent reference to it, so that the normal code flow
4461 * will not attempt to free it. oom_cfqq is linked to root_group
4462 * but shouldn't hold a reference as it'll never be unlinked. Lose
4463 * the reference from linking right away.
4465 cfq_init_cfqq(cfqd
, &cfqd
->oom_cfqq
, 1, 0);
4466 cfqd
->oom_cfqq
.ref
++;
4468 spin_lock_irq(q
->queue_lock
);
4469 cfq_link_cfqq_cfqg(&cfqd
->oom_cfqq
, cfqd
->root_group
);
4470 cfqg_put(cfqd
->root_group
);
4471 spin_unlock_irq(q
->queue_lock
);
4473 init_timer(&cfqd
->idle_slice_timer
);
4474 cfqd
->idle_slice_timer
.function
= cfq_idle_slice_timer
;
4475 cfqd
->idle_slice_timer
.data
= (unsigned long) cfqd
;
4477 INIT_WORK(&cfqd
->unplug_work
, cfq_kick_queue
);
4479 cfqd
->cfq_quantum
= cfq_quantum
;
4480 cfqd
->cfq_fifo_expire
[0] = cfq_fifo_expire
[0];
4481 cfqd
->cfq_fifo_expire
[1] = cfq_fifo_expire
[1];
4482 cfqd
->cfq_back_max
= cfq_back_max
;
4483 cfqd
->cfq_back_penalty
= cfq_back_penalty
;
4484 cfqd
->cfq_slice
[0] = cfq_slice_async
;
4485 cfqd
->cfq_slice
[1] = cfq_slice_sync
;
4486 cfqd
->cfq_target_latency
= cfq_target_latency
;
4487 cfqd
->cfq_slice_async_rq
= cfq_slice_async_rq
;
4488 cfqd
->cfq_slice_idle
= cfq_slice_idle
;
4489 cfqd
->cfq_group_idle
= cfq_group_idle
;
4490 cfqd
->cfq_latency
= 1;
4493 * we optimistically start assuming sync ops weren't delayed in last
4494 * second, in order to have larger depth for async operations.
4496 cfqd
->last_delayed_sync
= jiffies
- HZ
;
4501 kobject_put(&eq
->kobj
);
4505 static void cfq_registered_queue(struct request_queue
*q
)
4507 struct elevator_queue
*e
= q
->elevator
;
4508 struct cfq_data
*cfqd
= e
->elevator_data
;
4511 * Default to IOPS mode with no idling for SSDs
4513 if (blk_queue_nonrot(q
))
4514 cfqd
->cfq_slice_idle
= 0;
4518 * sysfs parts below -->
4521 cfq_var_show(unsigned int var
, char *page
)
4523 return sprintf(page
, "%u\n", var
);
4527 cfq_var_store(unsigned int *var
, const char *page
, size_t count
)
4529 char *p
= (char *) page
;
4531 *var
= simple_strtoul(p
, &p
, 10);
4535 #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \
4536 static ssize_t __FUNC(struct elevator_queue *e, char *page) \
4538 struct cfq_data *cfqd = e->elevator_data; \
4539 unsigned int __data = __VAR; \
4541 __data = jiffies_to_msecs(__data); \
4542 return cfq_var_show(__data, (page)); \
4544 SHOW_FUNCTION(cfq_quantum_show
, cfqd
->cfq_quantum
, 0);
4545 SHOW_FUNCTION(cfq_fifo_expire_sync_show
, cfqd
->cfq_fifo_expire
[1], 1);
4546 SHOW_FUNCTION(cfq_fifo_expire_async_show
, cfqd
->cfq_fifo_expire
[0], 1);
4547 SHOW_FUNCTION(cfq_back_seek_max_show
, cfqd
->cfq_back_max
, 0);
4548 SHOW_FUNCTION(cfq_back_seek_penalty_show
, cfqd
->cfq_back_penalty
, 0);
4549 SHOW_FUNCTION(cfq_slice_idle_show
, cfqd
->cfq_slice_idle
, 1);
4550 SHOW_FUNCTION(cfq_group_idle_show
, cfqd
->cfq_group_idle
, 1);
4551 SHOW_FUNCTION(cfq_slice_sync_show
, cfqd
->cfq_slice
[1], 1);
4552 SHOW_FUNCTION(cfq_slice_async_show
, cfqd
->cfq_slice
[0], 1);
4553 SHOW_FUNCTION(cfq_slice_async_rq_show
, cfqd
->cfq_slice_async_rq
, 0);
4554 SHOW_FUNCTION(cfq_low_latency_show
, cfqd
->cfq_latency
, 0);
4555 SHOW_FUNCTION(cfq_target_latency_show
, cfqd
->cfq_target_latency
, 1);
4556 #undef SHOW_FUNCTION
4558 #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \
4559 static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \
4561 struct cfq_data *cfqd = e->elevator_data; \
4562 unsigned int __data; \
4563 int ret = cfq_var_store(&__data, (page), count); \
4564 if (__data < (MIN)) \
4566 else if (__data > (MAX)) \
4569 *(__PTR) = msecs_to_jiffies(__data); \
4571 *(__PTR) = __data; \
4574 STORE_FUNCTION(cfq_quantum_store
, &cfqd
->cfq_quantum
, 1, UINT_MAX
, 0);
4575 STORE_FUNCTION(cfq_fifo_expire_sync_store
, &cfqd
->cfq_fifo_expire
[1], 1,
4577 STORE_FUNCTION(cfq_fifo_expire_async_store
, &cfqd
->cfq_fifo_expire
[0], 1,
4579 STORE_FUNCTION(cfq_back_seek_max_store
, &cfqd
->cfq_back_max
, 0, UINT_MAX
, 0);
4580 STORE_FUNCTION(cfq_back_seek_penalty_store
, &cfqd
->cfq_back_penalty
, 1,
4582 STORE_FUNCTION(cfq_slice_idle_store
, &cfqd
->cfq_slice_idle
, 0, UINT_MAX
, 1);
4583 STORE_FUNCTION(cfq_group_idle_store
, &cfqd
->cfq_group_idle
, 0, UINT_MAX
, 1);
4584 STORE_FUNCTION(cfq_slice_sync_store
, &cfqd
->cfq_slice
[1], 1, UINT_MAX
, 1);
4585 STORE_FUNCTION(cfq_slice_async_store
, &cfqd
->cfq_slice
[0], 1, UINT_MAX
, 1);
4586 STORE_FUNCTION(cfq_slice_async_rq_store
, &cfqd
->cfq_slice_async_rq
, 1,
4588 STORE_FUNCTION(cfq_low_latency_store
, &cfqd
->cfq_latency
, 0, 1, 0);
4589 STORE_FUNCTION(cfq_target_latency_store
, &cfqd
->cfq_target_latency
, 1, UINT_MAX
, 1);
4590 #undef STORE_FUNCTION
4592 #define CFQ_ATTR(name) \
4593 __ATTR(name, S_IRUGO|S_IWUSR, cfq_##name##_show, cfq_##name##_store)
4595 static struct elv_fs_entry cfq_attrs
[] = {
4597 CFQ_ATTR(fifo_expire_sync
),
4598 CFQ_ATTR(fifo_expire_async
),
4599 CFQ_ATTR(back_seek_max
),
4600 CFQ_ATTR(back_seek_penalty
),
4601 CFQ_ATTR(slice_sync
),
4602 CFQ_ATTR(slice_async
),
4603 CFQ_ATTR(slice_async_rq
),
4604 CFQ_ATTR(slice_idle
),
4605 CFQ_ATTR(group_idle
),
4606 CFQ_ATTR(low_latency
),
4607 CFQ_ATTR(target_latency
),
4611 static struct elevator_type iosched_cfq
= {
4613 .elevator_merge_fn
= cfq_merge
,
4614 .elevator_merged_fn
= cfq_merged_request
,
4615 .elevator_merge_req_fn
= cfq_merged_requests
,
4616 .elevator_allow_merge_fn
= cfq_allow_merge
,
4617 .elevator_bio_merged_fn
= cfq_bio_merged
,
4618 .elevator_dispatch_fn
= cfq_dispatch_requests
,
4619 .elevator_add_req_fn
= cfq_insert_request
,
4620 .elevator_activate_req_fn
= cfq_activate_request
,
4621 .elevator_deactivate_req_fn
= cfq_deactivate_request
,
4622 .elevator_completed_req_fn
= cfq_completed_request
,
4623 .elevator_former_req_fn
= elv_rb_former_request
,
4624 .elevator_latter_req_fn
= elv_rb_latter_request
,
4625 .elevator_init_icq_fn
= cfq_init_icq
,
4626 .elevator_exit_icq_fn
= cfq_exit_icq
,
4627 .elevator_set_req_fn
= cfq_set_request
,
4628 .elevator_put_req_fn
= cfq_put_request
,
4629 .elevator_may_queue_fn
= cfq_may_queue
,
4630 .elevator_init_fn
= cfq_init_queue
,
4631 .elevator_exit_fn
= cfq_exit_queue
,
4632 .elevator_registered_fn
= cfq_registered_queue
,
4634 .icq_size
= sizeof(struct cfq_io_cq
),
4635 .icq_align
= __alignof__(struct cfq_io_cq
),
4636 .elevator_attrs
= cfq_attrs
,
4637 .elevator_name
= "cfq",
4638 .elevator_owner
= THIS_MODULE
,
4641 #ifdef CONFIG_CFQ_GROUP_IOSCHED
4642 static struct blkcg_policy blkcg_policy_cfq
= {
4643 .cftypes
= cfq_blkcg_files
,
4645 .cpd_alloc_fn
= cfq_cpd_alloc
,
4646 .cpd_init_fn
= cfq_cpd_init
,
4647 .cpd_free_fn
= cfq_cpd_free
,
4649 .pd_alloc_fn
= cfq_pd_alloc
,
4650 .pd_init_fn
= cfq_pd_init
,
4651 .pd_offline_fn
= cfq_pd_offline
,
4652 .pd_free_fn
= cfq_pd_free
,
4653 .pd_reset_stats_fn
= cfq_pd_reset_stats
,
4657 static int __init
cfq_init(void)
4662 * could be 0 on HZ < 1000 setups
4664 if (!cfq_slice_async
)
4665 cfq_slice_async
= 1;
4666 if (!cfq_slice_idle
)
4669 #ifdef CONFIG_CFQ_GROUP_IOSCHED
4670 if (!cfq_group_idle
)
4673 ret
= blkcg_policy_register(&blkcg_policy_cfq
);
4681 cfq_pool
= KMEM_CACHE(cfq_queue
, 0);
4685 ret
= elv_register(&iosched_cfq
);
4692 kmem_cache_destroy(cfq_pool
);
4694 #ifdef CONFIG_CFQ_GROUP_IOSCHED
4695 blkcg_policy_unregister(&blkcg_policy_cfq
);
4700 static void __exit
cfq_exit(void)
4702 #ifdef CONFIG_CFQ_GROUP_IOSCHED
4703 blkcg_policy_unregister(&blkcg_policy_cfq
);
4705 elv_unregister(&iosched_cfq
);
4706 kmem_cache_destroy(cfq_pool
);
4709 module_init(cfq_init
);
4710 module_exit(cfq_exit
);
4712 MODULE_AUTHOR("Jens Axboe");
4713 MODULE_LICENSE("GPL");
4714 MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler");