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 disk time and nr sectors dispatched by this group */
189 struct blkg_stat time
;
190 #ifdef CONFIG_DEBUG_BLK_CGROUP
191 /* time not charged to this cgroup */
192 struct blkg_stat unaccounted_time
;
193 /* sum of number of ios queued across all samples */
194 struct blkg_stat avg_queue_size_sum
;
195 /* count of samples taken for average */
196 struct blkg_stat avg_queue_size_samples
;
197 /* how many times this group has been removed from service tree */
198 struct blkg_stat dequeue
;
199 /* total time spent waiting for it to be assigned a timeslice. */
200 struct blkg_stat group_wait_time
;
201 /* time spent idling for this blkcg_gq */
202 struct blkg_stat idle_time
;
203 /* total time with empty current active q with other requests queued */
204 struct blkg_stat empty_time
;
205 /* fields after this shouldn't be cleared on stat reset */
206 uint64_t start_group_wait_time
;
207 uint64_t start_idle_time
;
208 uint64_t start_empty_time
;
210 #endif /* CONFIG_DEBUG_BLK_CGROUP */
211 #endif /* CONFIG_CFQ_GROUP_IOSCHED */
214 /* Per-cgroup data */
215 struct cfq_group_data
{
216 /* must be the first member */
217 struct blkcg_policy_data cpd
;
220 unsigned int leaf_weight
;
223 /* This is per cgroup per device grouping structure */
225 /* must be the first member */
226 struct blkg_policy_data pd
;
228 /* group service_tree member */
229 struct rb_node rb_node
;
231 /* group service_tree key */
235 * The number of active cfqgs and sum of their weights under this
236 * cfqg. This covers this cfqg's leaf_weight and all children's
237 * weights, but does not cover weights of further descendants.
239 * If a cfqg is on the service tree, it's active. An active cfqg
240 * also activates its parent and contributes to the children_weight
244 unsigned int children_weight
;
247 * vfraction is the fraction of vdisktime that the tasks in this
248 * cfqg are entitled to. This is determined by compounding the
249 * ratios walking up from this cfqg to the root.
251 * It is in fixed point w/ CFQ_SERVICE_SHIFT and the sum of all
252 * vfractions on a service tree is approximately 1. The sum may
253 * deviate a bit due to rounding errors and fluctuations caused by
254 * cfqgs entering and leaving the service tree.
256 unsigned int vfraction
;
259 * There are two weights - (internal) weight is the weight of this
260 * cfqg against the sibling cfqgs. leaf_weight is the wight of
261 * this cfqg against the child cfqgs. For the root cfqg, both
262 * weights are kept in sync for backward compatibility.
265 unsigned int new_weight
;
266 unsigned int dev_weight
;
268 unsigned int leaf_weight
;
269 unsigned int new_leaf_weight
;
270 unsigned int dev_leaf_weight
;
272 /* number of cfqq currently on this group */
276 * Per group busy queues average. Useful for workload slice calc. We
277 * create the array for each prio class but at run time it is used
278 * only for RT and BE class and slot for IDLE class remains unused.
279 * This is primarily done to avoid confusion and a gcc warning.
281 unsigned int busy_queues_avg
[CFQ_PRIO_NR
];
283 * rr lists of queues with requests. We maintain service trees for
284 * RT and BE classes. These trees are subdivided in subclasses
285 * of SYNC, SYNC_NOIDLE and ASYNC based on workload type. For IDLE
286 * class there is no subclassification and all the cfq queues go on
287 * a single tree service_tree_idle.
288 * Counts are embedded in the cfq_rb_root
290 struct cfq_rb_root service_trees
[2][3];
291 struct cfq_rb_root service_tree_idle
;
293 unsigned long saved_wl_slice
;
294 enum wl_type_t saved_wl_type
;
295 enum wl_class_t saved_wl_class
;
297 /* number of requests that are on the dispatch list or inside driver */
299 struct cfq_ttime ttime
;
300 struct cfqg_stats stats
; /* stats for this cfqg */
302 /* async queue for each priority case */
303 struct cfq_queue
*async_cfqq
[2][IOPRIO_BE_NR
];
304 struct cfq_queue
*async_idle_cfqq
;
309 struct io_cq icq
; /* must be the first member */
310 struct cfq_queue
*cfqq
[2];
311 struct cfq_ttime ttime
;
312 int ioprio
; /* the current ioprio */
313 #ifdef CONFIG_CFQ_GROUP_IOSCHED
314 uint64_t blkcg_serial_nr
; /* the current blkcg serial */
319 * Per block device queue structure
322 struct request_queue
*queue
;
323 /* Root service tree for cfq_groups */
324 struct cfq_rb_root grp_service_tree
;
325 struct cfq_group
*root_group
;
328 * The priority currently being served
330 enum wl_class_t serving_wl_class
;
331 enum wl_type_t serving_wl_type
;
332 unsigned long workload_expires
;
333 struct cfq_group
*serving_group
;
336 * Each priority tree is sorted by next_request position. These
337 * trees are used when determining if two or more queues are
338 * interleaving requests (see cfq_close_cooperator).
340 struct rb_root prio_trees
[CFQ_PRIO_LISTS
];
342 unsigned int busy_queues
;
343 unsigned int busy_sync_queues
;
349 * queue-depth detection
355 * -1 => indeterminate, (cfq will behave as if NCQ is present, to allow better detection)
356 * 1 => NCQ is present (hw_tag_est_depth is the estimated max depth)
359 int hw_tag_est_depth
;
360 unsigned int hw_tag_samples
;
363 * idle window management
365 struct timer_list idle_slice_timer
;
366 struct work_struct unplug_work
;
368 struct cfq_queue
*active_queue
;
369 struct cfq_io_cq
*active_cic
;
371 sector_t last_position
;
374 * tunables, see top of file
376 unsigned int cfq_quantum
;
377 unsigned int cfq_fifo_expire
[2];
378 unsigned int cfq_back_penalty
;
379 unsigned int cfq_back_max
;
380 unsigned int cfq_slice
[2];
381 unsigned int cfq_slice_async_rq
;
382 unsigned int cfq_slice_idle
;
383 unsigned int cfq_group_idle
;
384 unsigned int cfq_latency
;
385 unsigned int cfq_target_latency
;
388 * Fallback dummy cfqq for extreme OOM conditions
390 struct cfq_queue oom_cfqq
;
392 unsigned long last_delayed_sync
;
395 static struct cfq_group
*cfq_get_next_cfqg(struct cfq_data
*cfqd
);
396 static void cfq_put_queue(struct cfq_queue
*cfqq
);
398 static struct cfq_rb_root
*st_for(struct cfq_group
*cfqg
,
399 enum wl_class_t
class,
405 if (class == IDLE_WORKLOAD
)
406 return &cfqg
->service_tree_idle
;
408 return &cfqg
->service_trees
[class][type
];
411 enum cfqq_state_flags
{
412 CFQ_CFQQ_FLAG_on_rr
= 0, /* on round-robin busy list */
413 CFQ_CFQQ_FLAG_wait_request
, /* waiting for a request */
414 CFQ_CFQQ_FLAG_must_dispatch
, /* must be allowed a dispatch */
415 CFQ_CFQQ_FLAG_must_alloc_slice
, /* per-slice must_alloc flag */
416 CFQ_CFQQ_FLAG_fifo_expire
, /* FIFO checked in this slice */
417 CFQ_CFQQ_FLAG_idle_window
, /* slice idling enabled */
418 CFQ_CFQQ_FLAG_prio_changed
, /* task priority has changed */
419 CFQ_CFQQ_FLAG_slice_new
, /* no requests dispatched in slice */
420 CFQ_CFQQ_FLAG_sync
, /* synchronous queue */
421 CFQ_CFQQ_FLAG_coop
, /* cfqq is shared */
422 CFQ_CFQQ_FLAG_split_coop
, /* shared cfqq will be splitted */
423 CFQ_CFQQ_FLAG_deep
, /* sync cfqq experienced large depth */
424 CFQ_CFQQ_FLAG_wait_busy
, /* Waiting for next request */
427 #define CFQ_CFQQ_FNS(name) \
428 static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \
430 (cfqq)->flags |= (1 << CFQ_CFQQ_FLAG_##name); \
432 static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \
434 (cfqq)->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \
436 static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \
438 return ((cfqq)->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \
442 CFQ_CFQQ_FNS(wait_request
);
443 CFQ_CFQQ_FNS(must_dispatch
);
444 CFQ_CFQQ_FNS(must_alloc_slice
);
445 CFQ_CFQQ_FNS(fifo_expire
);
446 CFQ_CFQQ_FNS(idle_window
);
447 CFQ_CFQQ_FNS(prio_changed
);
448 CFQ_CFQQ_FNS(slice_new
);
451 CFQ_CFQQ_FNS(split_coop
);
453 CFQ_CFQQ_FNS(wait_busy
);
456 #if defined(CONFIG_CFQ_GROUP_IOSCHED) && defined(CONFIG_DEBUG_BLK_CGROUP)
458 /* cfqg stats flags */
459 enum cfqg_stats_flags
{
460 CFQG_stats_waiting
= 0,
465 #define CFQG_FLAG_FNS(name) \
466 static inline void cfqg_stats_mark_##name(struct cfqg_stats *stats) \
468 stats->flags |= (1 << CFQG_stats_##name); \
470 static inline void cfqg_stats_clear_##name(struct cfqg_stats *stats) \
472 stats->flags &= ~(1 << CFQG_stats_##name); \
474 static inline int cfqg_stats_##name(struct cfqg_stats *stats) \
476 return (stats->flags & (1 << CFQG_stats_##name)) != 0; \
479 CFQG_FLAG_FNS(waiting)
480 CFQG_FLAG_FNS(idling
)
484 /* This should be called with the queue_lock held. */
485 static void cfqg_stats_update_group_wait_time(struct cfqg_stats
*stats
)
487 unsigned long long now
;
489 if (!cfqg_stats_waiting(stats
))
493 if (time_after64(now
, stats
->start_group_wait_time
))
494 blkg_stat_add(&stats
->group_wait_time
,
495 now
- stats
->start_group_wait_time
);
496 cfqg_stats_clear_waiting(stats
);
499 /* This should be called with the queue_lock held. */
500 static void cfqg_stats_set_start_group_wait_time(struct cfq_group
*cfqg
,
501 struct cfq_group
*curr_cfqg
)
503 struct cfqg_stats
*stats
= &cfqg
->stats
;
505 if (cfqg_stats_waiting(stats
))
507 if (cfqg
== curr_cfqg
)
509 stats
->start_group_wait_time
= sched_clock();
510 cfqg_stats_mark_waiting(stats
);
513 /* This should be called with the queue_lock held. */
514 static void cfqg_stats_end_empty_time(struct cfqg_stats
*stats
)
516 unsigned long long now
;
518 if (!cfqg_stats_empty(stats
))
522 if (time_after64(now
, stats
->start_empty_time
))
523 blkg_stat_add(&stats
->empty_time
,
524 now
- stats
->start_empty_time
);
525 cfqg_stats_clear_empty(stats
);
528 static void cfqg_stats_update_dequeue(struct cfq_group
*cfqg
)
530 blkg_stat_add(&cfqg
->stats
.dequeue
, 1);
533 static void cfqg_stats_set_start_empty_time(struct cfq_group
*cfqg
)
535 struct cfqg_stats
*stats
= &cfqg
->stats
;
537 if (blkg_rwstat_total(&stats
->queued
))
541 * group is already marked empty. This can happen if cfqq got new
542 * request in parent group and moved to this group while being added
543 * to service tree. Just ignore the event and move on.
545 if (cfqg_stats_empty(stats
))
548 stats
->start_empty_time
= sched_clock();
549 cfqg_stats_mark_empty(stats
);
552 static void cfqg_stats_update_idle_time(struct cfq_group
*cfqg
)
554 struct cfqg_stats
*stats
= &cfqg
->stats
;
556 if (cfqg_stats_idling(stats
)) {
557 unsigned long long now
= sched_clock();
559 if (time_after64(now
, stats
->start_idle_time
))
560 blkg_stat_add(&stats
->idle_time
,
561 now
- stats
->start_idle_time
);
562 cfqg_stats_clear_idling(stats
);
566 static void cfqg_stats_set_start_idle_time(struct cfq_group
*cfqg
)
568 struct cfqg_stats
*stats
= &cfqg
->stats
;
570 BUG_ON(cfqg_stats_idling(stats
));
572 stats
->start_idle_time
= sched_clock();
573 cfqg_stats_mark_idling(stats
);
576 static void cfqg_stats_update_avg_queue_size(struct cfq_group
*cfqg
)
578 struct cfqg_stats
*stats
= &cfqg
->stats
;
580 blkg_stat_add(&stats
->avg_queue_size_sum
,
581 blkg_rwstat_total(&stats
->queued
));
582 blkg_stat_add(&stats
->avg_queue_size_samples
, 1);
583 cfqg_stats_update_group_wait_time(stats
);
586 #else /* CONFIG_CFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */
588 static inline void cfqg_stats_set_start_group_wait_time(struct cfq_group
*cfqg
, struct cfq_group
*curr_cfqg
) { }
589 static inline void cfqg_stats_end_empty_time(struct cfqg_stats
*stats
) { }
590 static inline void cfqg_stats_update_dequeue(struct cfq_group
*cfqg
) { }
591 static inline void cfqg_stats_set_start_empty_time(struct cfq_group
*cfqg
) { }
592 static inline void cfqg_stats_update_idle_time(struct cfq_group
*cfqg
) { }
593 static inline void cfqg_stats_set_start_idle_time(struct cfq_group
*cfqg
) { }
594 static inline void cfqg_stats_update_avg_queue_size(struct cfq_group
*cfqg
) { }
596 #endif /* CONFIG_CFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */
598 #ifdef CONFIG_CFQ_GROUP_IOSCHED
600 static inline struct cfq_group
*pd_to_cfqg(struct blkg_policy_data
*pd
)
602 return pd
? container_of(pd
, struct cfq_group
, pd
) : NULL
;
605 static struct cfq_group_data
606 *cpd_to_cfqgd(struct blkcg_policy_data
*cpd
)
608 return cpd
? container_of(cpd
, struct cfq_group_data
, cpd
) : NULL
;
611 static inline struct blkcg_gq
*cfqg_to_blkg(struct cfq_group
*cfqg
)
613 return pd_to_blkg(&cfqg
->pd
);
616 static struct blkcg_policy blkcg_policy_cfq
;
618 static inline struct cfq_group
*blkg_to_cfqg(struct blkcg_gq
*blkg
)
620 return pd_to_cfqg(blkg_to_pd(blkg
, &blkcg_policy_cfq
));
623 static struct cfq_group_data
*blkcg_to_cfqgd(struct blkcg
*blkcg
)
625 return cpd_to_cfqgd(blkcg_to_cpd(blkcg
, &blkcg_policy_cfq
));
628 static inline struct cfq_group
*cfqg_parent(struct cfq_group
*cfqg
)
630 struct blkcg_gq
*pblkg
= cfqg_to_blkg(cfqg
)->parent
;
632 return pblkg
? blkg_to_cfqg(pblkg
) : NULL
;
635 static inline void cfqg_get(struct cfq_group
*cfqg
)
637 return blkg_get(cfqg_to_blkg(cfqg
));
640 static inline void cfqg_put(struct cfq_group
*cfqg
)
642 return blkg_put(cfqg_to_blkg(cfqg
));
645 #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) do { \
648 blkg_path(cfqg_to_blkg((cfqq)->cfqg), __pbuf, sizeof(__pbuf)); \
649 blk_add_trace_msg((cfqd)->queue, "cfq%d%c%c %s " fmt, (cfqq)->pid, \
650 cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \
651 cfqq_type((cfqq)) == SYNC_NOIDLE_WORKLOAD ? 'N' : ' ',\
655 #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) do { \
658 blkg_path(cfqg_to_blkg(cfqg), __pbuf, sizeof(__pbuf)); \
659 blk_add_trace_msg((cfqd)->queue, "%s " fmt, __pbuf, ##args); \
662 static inline void cfqg_stats_update_io_add(struct cfq_group
*cfqg
,
663 struct cfq_group
*curr_cfqg
, int rw
)
665 blkg_rwstat_add(&cfqg
->stats
.queued
, rw
, 1);
666 cfqg_stats_end_empty_time(&cfqg
->stats
);
667 cfqg_stats_set_start_group_wait_time(cfqg
, curr_cfqg
);
670 static inline void cfqg_stats_update_timeslice_used(struct cfq_group
*cfqg
,
671 unsigned long time
, unsigned long unaccounted_time
)
673 blkg_stat_add(&cfqg
->stats
.time
, time
);
674 #ifdef CONFIG_DEBUG_BLK_CGROUP
675 blkg_stat_add(&cfqg
->stats
.unaccounted_time
, unaccounted_time
);
679 static inline void cfqg_stats_update_io_remove(struct cfq_group
*cfqg
, int rw
)
681 blkg_rwstat_add(&cfqg
->stats
.queued
, rw
, -1);
684 static inline void cfqg_stats_update_io_merged(struct cfq_group
*cfqg
, int rw
)
686 blkg_rwstat_add(&cfqg
->stats
.merged
, rw
, 1);
689 static inline void cfqg_stats_update_completion(struct cfq_group
*cfqg
,
690 uint64_t start_time
, uint64_t io_start_time
, int rw
)
692 struct cfqg_stats
*stats
= &cfqg
->stats
;
693 unsigned long long now
= sched_clock();
695 if (time_after64(now
, io_start_time
))
696 blkg_rwstat_add(&stats
->service_time
, rw
, now
- io_start_time
);
697 if (time_after64(io_start_time
, start_time
))
698 blkg_rwstat_add(&stats
->wait_time
, rw
,
699 io_start_time
- start_time
);
703 static void cfqg_stats_reset(struct cfqg_stats
*stats
)
705 /* queued stats shouldn't be cleared */
706 blkg_rwstat_reset(&stats
->merged
);
707 blkg_rwstat_reset(&stats
->service_time
);
708 blkg_rwstat_reset(&stats
->wait_time
);
709 blkg_stat_reset(&stats
->time
);
710 #ifdef CONFIG_DEBUG_BLK_CGROUP
711 blkg_stat_reset(&stats
->unaccounted_time
);
712 blkg_stat_reset(&stats
->avg_queue_size_sum
);
713 blkg_stat_reset(&stats
->avg_queue_size_samples
);
714 blkg_stat_reset(&stats
->dequeue
);
715 blkg_stat_reset(&stats
->group_wait_time
);
716 blkg_stat_reset(&stats
->idle_time
);
717 blkg_stat_reset(&stats
->empty_time
);
722 static void cfqg_stats_add_aux(struct cfqg_stats
*to
, struct cfqg_stats
*from
)
724 /* queued stats shouldn't be cleared */
725 blkg_rwstat_add_aux(&to
->merged
, &from
->merged
);
726 blkg_rwstat_add_aux(&to
->service_time
, &from
->service_time
);
727 blkg_rwstat_add_aux(&to
->wait_time
, &from
->wait_time
);
728 blkg_stat_add_aux(&from
->time
, &from
->time
);
729 #ifdef CONFIG_DEBUG_BLK_CGROUP
730 blkg_stat_add_aux(&to
->unaccounted_time
, &from
->unaccounted_time
);
731 blkg_stat_add_aux(&to
->avg_queue_size_sum
, &from
->avg_queue_size_sum
);
732 blkg_stat_add_aux(&to
->avg_queue_size_samples
, &from
->avg_queue_size_samples
);
733 blkg_stat_add_aux(&to
->dequeue
, &from
->dequeue
);
734 blkg_stat_add_aux(&to
->group_wait_time
, &from
->group_wait_time
);
735 blkg_stat_add_aux(&to
->idle_time
, &from
->idle_time
);
736 blkg_stat_add_aux(&to
->empty_time
, &from
->empty_time
);
741 * Transfer @cfqg's stats to its parent's aux counts so that the ancestors'
742 * recursive stats can still account for the amount used by this cfqg after
745 static void cfqg_stats_xfer_dead(struct cfq_group
*cfqg
)
747 struct cfq_group
*parent
= cfqg_parent(cfqg
);
749 lockdep_assert_held(cfqg_to_blkg(cfqg
)->q
->queue_lock
);
751 if (unlikely(!parent
))
754 cfqg_stats_add_aux(&parent
->stats
, &cfqg
->stats
);
755 cfqg_stats_reset(&cfqg
->stats
);
758 #else /* CONFIG_CFQ_GROUP_IOSCHED */
760 static inline struct cfq_group
*cfqg_parent(struct cfq_group
*cfqg
) { return NULL
; }
761 static inline void cfqg_get(struct cfq_group
*cfqg
) { }
762 static inline void cfqg_put(struct cfq_group
*cfqg
) { }
764 #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \
765 blk_add_trace_msg((cfqd)->queue, "cfq%d%c%c " fmt, (cfqq)->pid, \
766 cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \
767 cfqq_type((cfqq)) == SYNC_NOIDLE_WORKLOAD ? 'N' : ' ',\
769 #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) do {} while (0)
771 static inline void cfqg_stats_update_io_add(struct cfq_group
*cfqg
,
772 struct cfq_group
*curr_cfqg
, int rw
) { }
773 static inline void cfqg_stats_update_timeslice_used(struct cfq_group
*cfqg
,
774 unsigned long time
, unsigned long unaccounted_time
) { }
775 static inline void cfqg_stats_update_io_remove(struct cfq_group
*cfqg
, int rw
) { }
776 static inline void cfqg_stats_update_io_merged(struct cfq_group
*cfqg
, int rw
) { }
777 static inline void cfqg_stats_update_completion(struct cfq_group
*cfqg
,
778 uint64_t start_time
, uint64_t io_start_time
, int rw
) { }
780 #endif /* CONFIG_CFQ_GROUP_IOSCHED */
782 #define cfq_log(cfqd, fmt, args...) \
783 blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args)
785 /* Traverses through cfq group service trees */
786 #define for_each_cfqg_st(cfqg, i, j, st) \
787 for (i = 0; i <= IDLE_WORKLOAD; i++) \
788 for (j = 0, st = i < IDLE_WORKLOAD ? &cfqg->service_trees[i][j]\
789 : &cfqg->service_tree_idle; \
790 (i < IDLE_WORKLOAD && j <= SYNC_WORKLOAD) || \
791 (i == IDLE_WORKLOAD && j == 0); \
792 j++, st = i < IDLE_WORKLOAD ? \
793 &cfqg->service_trees[i][j]: NULL) \
795 static inline bool cfq_io_thinktime_big(struct cfq_data *cfqd,
796 struct cfq_ttime
*ttime
, bool group_idle
)
799 if (!sample_valid(ttime
->ttime_samples
))
802 slice
= cfqd
->cfq_group_idle
;
804 slice
= cfqd
->cfq_slice_idle
;
805 return ttime
->ttime_mean
> slice
;
808 static inline bool iops_mode(struct cfq_data
*cfqd
)
811 * If we are not idling on queues and it is a NCQ drive, parallel
812 * execution of requests is on and measuring time is not possible
813 * in most of the cases until and unless we drive shallower queue
814 * depths and that becomes a performance bottleneck. In such cases
815 * switch to start providing fairness in terms of number of IOs.
817 if (!cfqd
->cfq_slice_idle
&& cfqd
->hw_tag
)
823 static inline enum wl_class_t
cfqq_class(struct cfq_queue
*cfqq
)
825 if (cfq_class_idle(cfqq
))
826 return IDLE_WORKLOAD
;
827 if (cfq_class_rt(cfqq
))
833 static enum wl_type_t
cfqq_type(struct cfq_queue
*cfqq
)
835 if (!cfq_cfqq_sync(cfqq
))
836 return ASYNC_WORKLOAD
;
837 if (!cfq_cfqq_idle_window(cfqq
))
838 return SYNC_NOIDLE_WORKLOAD
;
839 return SYNC_WORKLOAD
;
842 static inline int cfq_group_busy_queues_wl(enum wl_class_t wl_class
,
843 struct cfq_data
*cfqd
,
844 struct cfq_group
*cfqg
)
846 if (wl_class
== IDLE_WORKLOAD
)
847 return cfqg
->service_tree_idle
.count
;
849 return cfqg
->service_trees
[wl_class
][ASYNC_WORKLOAD
].count
+
850 cfqg
->service_trees
[wl_class
][SYNC_NOIDLE_WORKLOAD
].count
+
851 cfqg
->service_trees
[wl_class
][SYNC_WORKLOAD
].count
;
854 static inline int cfqg_busy_async_queues(struct cfq_data
*cfqd
,
855 struct cfq_group
*cfqg
)
857 return cfqg
->service_trees
[RT_WORKLOAD
][ASYNC_WORKLOAD
].count
+
858 cfqg
->service_trees
[BE_WORKLOAD
][ASYNC_WORKLOAD
].count
;
861 static void cfq_dispatch_insert(struct request_queue
*, struct request
*);
862 static struct cfq_queue
*cfq_get_queue(struct cfq_data
*cfqd
, bool is_sync
,
863 struct cfq_io_cq
*cic
, struct bio
*bio
);
865 static inline struct cfq_io_cq
*icq_to_cic(struct io_cq
*icq
)
867 /* cic->icq is the first member, %NULL will convert to %NULL */
868 return container_of(icq
, struct cfq_io_cq
, icq
);
871 static inline struct cfq_io_cq
*cfq_cic_lookup(struct cfq_data
*cfqd
,
872 struct io_context
*ioc
)
875 return icq_to_cic(ioc_lookup_icq(ioc
, cfqd
->queue
));
879 static inline struct cfq_queue
*cic_to_cfqq(struct cfq_io_cq
*cic
, bool is_sync
)
881 return cic
->cfqq
[is_sync
];
884 static inline void cic_set_cfqq(struct cfq_io_cq
*cic
, struct cfq_queue
*cfqq
,
887 cic
->cfqq
[is_sync
] = cfqq
;
890 static inline struct cfq_data
*cic_to_cfqd(struct cfq_io_cq
*cic
)
892 return cic
->icq
.q
->elevator
->elevator_data
;
896 * We regard a request as SYNC, if it's either a read or has the SYNC bit
897 * set (in which case it could also be direct WRITE).
899 static inline bool cfq_bio_sync(struct bio
*bio
)
901 return bio_data_dir(bio
) == READ
|| (bio
->bi_rw
& REQ_SYNC
);
905 * scheduler run of queue, if there are requests pending and no one in the
906 * driver that will restart queueing
908 static inline void cfq_schedule_dispatch(struct cfq_data
*cfqd
)
910 if (cfqd
->busy_queues
) {
911 cfq_log(cfqd
, "schedule dispatch");
912 kblockd_schedule_work(&cfqd
->unplug_work
);
917 * Scale schedule slice based on io priority. Use the sync time slice only
918 * if a queue is marked sync and has sync io queued. A sync queue with async
919 * io only, should not get full sync slice length.
921 static inline int cfq_prio_slice(struct cfq_data
*cfqd
, bool sync
,
924 const int base_slice
= cfqd
->cfq_slice
[sync
];
926 WARN_ON(prio
>= IOPRIO_BE_NR
);
928 return base_slice
+ (base_slice
/CFQ_SLICE_SCALE
* (4 - prio
));
932 cfq_prio_to_slice(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
934 return cfq_prio_slice(cfqd
, cfq_cfqq_sync(cfqq
), cfqq
->ioprio
);
938 * cfqg_scale_charge - scale disk time charge according to cfqg weight
939 * @charge: disk time being charged
940 * @vfraction: vfraction of the cfqg, fixed point w/ CFQ_SERVICE_SHIFT
942 * Scale @charge according to @vfraction, which is in range (0, 1]. The
943 * scaling is inversely proportional.
945 * scaled = charge / vfraction
947 * The result is also in fixed point w/ CFQ_SERVICE_SHIFT.
949 static inline u64
cfqg_scale_charge(unsigned long charge
,
950 unsigned int vfraction
)
952 u64 c
= charge
<< CFQ_SERVICE_SHIFT
; /* make it fixed point */
954 /* charge / vfraction */
955 c
<<= CFQ_SERVICE_SHIFT
;
956 do_div(c
, vfraction
);
960 static inline u64
max_vdisktime(u64 min_vdisktime
, u64 vdisktime
)
962 s64 delta
= (s64
)(vdisktime
- min_vdisktime
);
964 min_vdisktime
= vdisktime
;
966 return min_vdisktime
;
969 static inline u64
min_vdisktime(u64 min_vdisktime
, u64 vdisktime
)
971 s64 delta
= (s64
)(vdisktime
- min_vdisktime
);
973 min_vdisktime
= vdisktime
;
975 return min_vdisktime
;
978 static void update_min_vdisktime(struct cfq_rb_root
*st
)
980 struct cfq_group
*cfqg
;
983 cfqg
= rb_entry_cfqg(st
->left
);
984 st
->min_vdisktime
= max_vdisktime(st
->min_vdisktime
,
990 * get averaged number of queues of RT/BE priority.
991 * average is updated, with a formula that gives more weight to higher numbers,
992 * to quickly follows sudden increases and decrease slowly
995 static inline unsigned cfq_group_get_avg_queues(struct cfq_data
*cfqd
,
996 struct cfq_group
*cfqg
, bool rt
)
998 unsigned min_q
, max_q
;
999 unsigned mult
= cfq_hist_divisor
- 1;
1000 unsigned round
= cfq_hist_divisor
/ 2;
1001 unsigned busy
= cfq_group_busy_queues_wl(rt
, cfqd
, cfqg
);
1003 min_q
= min(cfqg
->busy_queues_avg
[rt
], busy
);
1004 max_q
= max(cfqg
->busy_queues_avg
[rt
], busy
);
1005 cfqg
->busy_queues_avg
[rt
] = (mult
* max_q
+ min_q
+ round
) /
1007 return cfqg
->busy_queues_avg
[rt
];
1010 static inline unsigned
1011 cfq_group_slice(struct cfq_data
*cfqd
, struct cfq_group
*cfqg
)
1013 return cfqd
->cfq_target_latency
* cfqg
->vfraction
>> CFQ_SERVICE_SHIFT
;
1016 static inline unsigned
1017 cfq_scaled_cfqq_slice(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
1019 unsigned slice
= cfq_prio_to_slice(cfqd
, cfqq
);
1020 if (cfqd
->cfq_latency
) {
1022 * interested queues (we consider only the ones with the same
1023 * priority class in the cfq group)
1025 unsigned iq
= cfq_group_get_avg_queues(cfqd
, cfqq
->cfqg
,
1026 cfq_class_rt(cfqq
));
1027 unsigned sync_slice
= cfqd
->cfq_slice
[1];
1028 unsigned expect_latency
= sync_slice
* iq
;
1029 unsigned group_slice
= cfq_group_slice(cfqd
, cfqq
->cfqg
);
1031 if (expect_latency
> group_slice
) {
1032 unsigned base_low_slice
= 2 * cfqd
->cfq_slice_idle
;
1033 /* scale low_slice according to IO priority
1034 * and sync vs async */
1035 unsigned low_slice
=
1036 min(slice
, base_low_slice
* slice
/ sync_slice
);
1037 /* the adapted slice value is scaled to fit all iqs
1038 * into the target latency */
1039 slice
= max(slice
* group_slice
/ expect_latency
,
1047 cfq_set_prio_slice(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
1049 unsigned slice
= cfq_scaled_cfqq_slice(cfqd
, cfqq
);
1051 cfqq
->slice_start
= jiffies
;
1052 cfqq
->slice_end
= jiffies
+ slice
;
1053 cfqq
->allocated_slice
= slice
;
1054 cfq_log_cfqq(cfqd
, cfqq
, "set_slice=%lu", cfqq
->slice_end
- jiffies
);
1058 * We need to wrap this check in cfq_cfqq_slice_new(), since ->slice_end
1059 * isn't valid until the first request from the dispatch is activated
1060 * and the slice time set.
1062 static inline bool cfq_slice_used(struct cfq_queue
*cfqq
)
1064 if (cfq_cfqq_slice_new(cfqq
))
1066 if (time_before(jiffies
, cfqq
->slice_end
))
1073 * Lifted from AS - choose which of rq1 and rq2 that is best served now.
1074 * We choose the request that is closest to the head right now. Distance
1075 * behind the head is penalized and only allowed to a certain extent.
1077 static struct request
*
1078 cfq_choose_req(struct cfq_data
*cfqd
, struct request
*rq1
, struct request
*rq2
, sector_t last
)
1080 sector_t s1
, s2
, d1
= 0, d2
= 0;
1081 unsigned long back_max
;
1082 #define CFQ_RQ1_WRAP 0x01 /* request 1 wraps */
1083 #define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */
1084 unsigned wrap
= 0; /* bit mask: requests behind the disk head? */
1086 if (rq1
== NULL
|| rq1
== rq2
)
1091 if (rq_is_sync(rq1
) != rq_is_sync(rq2
))
1092 return rq_is_sync(rq1
) ? rq1
: rq2
;
1094 if ((rq1
->cmd_flags
^ rq2
->cmd_flags
) & REQ_PRIO
)
1095 return rq1
->cmd_flags
& REQ_PRIO
? rq1
: rq2
;
1097 s1
= blk_rq_pos(rq1
);
1098 s2
= blk_rq_pos(rq2
);
1101 * by definition, 1KiB is 2 sectors
1103 back_max
= cfqd
->cfq_back_max
* 2;
1106 * Strict one way elevator _except_ in the case where we allow
1107 * short backward seeks which are biased as twice the cost of a
1108 * similar forward seek.
1112 else if (s1
+ back_max
>= last
)
1113 d1
= (last
- s1
) * cfqd
->cfq_back_penalty
;
1115 wrap
|= CFQ_RQ1_WRAP
;
1119 else if (s2
+ back_max
>= last
)
1120 d2
= (last
- s2
) * cfqd
->cfq_back_penalty
;
1122 wrap
|= CFQ_RQ2_WRAP
;
1124 /* Found required data */
1127 * By doing switch() on the bit mask "wrap" we avoid having to
1128 * check two variables for all permutations: --> faster!
1131 case 0: /* common case for CFQ: rq1 and rq2 not wrapped */
1147 case (CFQ_RQ1_WRAP
|CFQ_RQ2_WRAP
): /* both rqs wrapped */
1150 * Since both rqs are wrapped,
1151 * start with the one that's further behind head
1152 * (--> only *one* back seek required),
1153 * since back seek takes more time than forward.
1163 * The below is leftmost cache rbtree addon
1165 static struct cfq_queue
*cfq_rb_first(struct cfq_rb_root
*root
)
1167 /* Service tree is empty */
1172 root
->left
= rb_first(&root
->rb
);
1175 return rb_entry(root
->left
, struct cfq_queue
, rb_node
);
1180 static struct cfq_group
*cfq_rb_first_group(struct cfq_rb_root
*root
)
1183 root
->left
= rb_first(&root
->rb
);
1186 return rb_entry_cfqg(root
->left
);
1191 static void rb_erase_init(struct rb_node
*n
, struct rb_root
*root
)
1197 static void cfq_rb_erase(struct rb_node
*n
, struct cfq_rb_root
*root
)
1199 if (root
->left
== n
)
1201 rb_erase_init(n
, &root
->rb
);
1206 * would be nice to take fifo expire time into account as well
1208 static struct request
*
1209 cfq_find_next_rq(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
1210 struct request
*last
)
1212 struct rb_node
*rbnext
= rb_next(&last
->rb_node
);
1213 struct rb_node
*rbprev
= rb_prev(&last
->rb_node
);
1214 struct request
*next
= NULL
, *prev
= NULL
;
1216 BUG_ON(RB_EMPTY_NODE(&last
->rb_node
));
1219 prev
= rb_entry_rq(rbprev
);
1222 next
= rb_entry_rq(rbnext
);
1224 rbnext
= rb_first(&cfqq
->sort_list
);
1225 if (rbnext
&& rbnext
!= &last
->rb_node
)
1226 next
= rb_entry_rq(rbnext
);
1229 return cfq_choose_req(cfqd
, next
, prev
, blk_rq_pos(last
));
1232 static unsigned long cfq_slice_offset(struct cfq_data
*cfqd
,
1233 struct cfq_queue
*cfqq
)
1236 * just an approximation, should be ok.
1238 return (cfqq
->cfqg
->nr_cfqq
- 1) * (cfq_prio_slice(cfqd
, 1, 0) -
1239 cfq_prio_slice(cfqd
, cfq_cfqq_sync(cfqq
), cfqq
->ioprio
));
1243 cfqg_key(struct cfq_rb_root
*st
, struct cfq_group
*cfqg
)
1245 return cfqg
->vdisktime
- st
->min_vdisktime
;
1249 __cfq_group_service_tree_add(struct cfq_rb_root
*st
, struct cfq_group
*cfqg
)
1251 struct rb_node
**node
= &st
->rb
.rb_node
;
1252 struct rb_node
*parent
= NULL
;
1253 struct cfq_group
*__cfqg
;
1254 s64 key
= cfqg_key(st
, cfqg
);
1257 while (*node
!= NULL
) {
1259 __cfqg
= rb_entry_cfqg(parent
);
1261 if (key
< cfqg_key(st
, __cfqg
))
1262 node
= &parent
->rb_left
;
1264 node
= &parent
->rb_right
;
1270 st
->left
= &cfqg
->rb_node
;
1272 rb_link_node(&cfqg
->rb_node
, parent
, node
);
1273 rb_insert_color(&cfqg
->rb_node
, &st
->rb
);
1277 * This has to be called only on activation of cfqg
1280 cfq_update_group_weight(struct cfq_group
*cfqg
)
1282 if (cfqg
->new_weight
) {
1283 cfqg
->weight
= cfqg
->new_weight
;
1284 cfqg
->new_weight
= 0;
1289 cfq_update_group_leaf_weight(struct cfq_group
*cfqg
)
1291 BUG_ON(!RB_EMPTY_NODE(&cfqg
->rb_node
));
1293 if (cfqg
->new_leaf_weight
) {
1294 cfqg
->leaf_weight
= cfqg
->new_leaf_weight
;
1295 cfqg
->new_leaf_weight
= 0;
1300 cfq_group_service_tree_add(struct cfq_rb_root
*st
, struct cfq_group
*cfqg
)
1302 unsigned int vfr
= 1 << CFQ_SERVICE_SHIFT
; /* start with 1 */
1303 struct cfq_group
*pos
= cfqg
;
1304 struct cfq_group
*parent
;
1307 /* add to the service tree */
1308 BUG_ON(!RB_EMPTY_NODE(&cfqg
->rb_node
));
1311 * Update leaf_weight. We cannot update weight at this point
1312 * because cfqg might already have been activated and is
1313 * contributing its current weight to the parent's child_weight.
1315 cfq_update_group_leaf_weight(cfqg
);
1316 __cfq_group_service_tree_add(st
, cfqg
);
1319 * Activate @cfqg and calculate the portion of vfraction @cfqg is
1320 * entitled to. vfraction is calculated by walking the tree
1321 * towards the root calculating the fraction it has at each level.
1322 * The compounded ratio is how much vfraction @cfqg owns.
1324 * Start with the proportion tasks in this cfqg has against active
1325 * children cfqgs - its leaf_weight against children_weight.
1327 propagate
= !pos
->nr_active
++;
1328 pos
->children_weight
+= pos
->leaf_weight
;
1329 vfr
= vfr
* pos
->leaf_weight
/ pos
->children_weight
;
1332 * Compound ->weight walking up the tree. Both activation and
1333 * vfraction calculation are done in the same loop. Propagation
1334 * stops once an already activated node is met. vfraction
1335 * calculation should always continue to the root.
1337 while ((parent
= cfqg_parent(pos
))) {
1339 cfq_update_group_weight(pos
);
1340 propagate
= !parent
->nr_active
++;
1341 parent
->children_weight
+= pos
->weight
;
1343 vfr
= vfr
* pos
->weight
/ parent
->children_weight
;
1347 cfqg
->vfraction
= max_t(unsigned, vfr
, 1);
1351 cfq_group_notify_queue_add(struct cfq_data
*cfqd
, struct cfq_group
*cfqg
)
1353 struct cfq_rb_root
*st
= &cfqd
->grp_service_tree
;
1354 struct cfq_group
*__cfqg
;
1358 if (!RB_EMPTY_NODE(&cfqg
->rb_node
))
1362 * Currently put the group at the end. Later implement something
1363 * so that groups get lesser vtime based on their weights, so that
1364 * if group does not loose all if it was not continuously backlogged.
1366 n
= rb_last(&st
->rb
);
1368 __cfqg
= rb_entry_cfqg(n
);
1369 cfqg
->vdisktime
= __cfqg
->vdisktime
+ CFQ_IDLE_DELAY
;
1371 cfqg
->vdisktime
= st
->min_vdisktime
;
1372 cfq_group_service_tree_add(st
, cfqg
);
1376 cfq_group_service_tree_del(struct cfq_rb_root
*st
, struct cfq_group
*cfqg
)
1378 struct cfq_group
*pos
= cfqg
;
1382 * Undo activation from cfq_group_service_tree_add(). Deactivate
1383 * @cfqg and propagate deactivation upwards.
1385 propagate
= !--pos
->nr_active
;
1386 pos
->children_weight
-= pos
->leaf_weight
;
1389 struct cfq_group
*parent
= cfqg_parent(pos
);
1391 /* @pos has 0 nr_active at this point */
1392 WARN_ON_ONCE(pos
->children_weight
);
1398 propagate
= !--parent
->nr_active
;
1399 parent
->children_weight
-= pos
->weight
;
1403 /* remove from the service tree */
1404 if (!RB_EMPTY_NODE(&cfqg
->rb_node
))
1405 cfq_rb_erase(&cfqg
->rb_node
, st
);
1409 cfq_group_notify_queue_del(struct cfq_data
*cfqd
, struct cfq_group
*cfqg
)
1411 struct cfq_rb_root
*st
= &cfqd
->grp_service_tree
;
1413 BUG_ON(cfqg
->nr_cfqq
< 1);
1416 /* If there are other cfq queues under this group, don't delete it */
1420 cfq_log_cfqg(cfqd
, cfqg
, "del_from_rr group");
1421 cfq_group_service_tree_del(st
, cfqg
);
1422 cfqg
->saved_wl_slice
= 0;
1423 cfqg_stats_update_dequeue(cfqg
);
1426 static inline unsigned int cfq_cfqq_slice_usage(struct cfq_queue
*cfqq
,
1427 unsigned int *unaccounted_time
)
1429 unsigned int slice_used
;
1432 * Queue got expired before even a single request completed or
1433 * got expired immediately after first request completion.
1435 if (!cfqq
->slice_start
|| cfqq
->slice_start
== jiffies
) {
1437 * Also charge the seek time incurred to the group, otherwise
1438 * if there are mutiple queues in the group, each can dispatch
1439 * a single request on seeky media and cause lots of seek time
1440 * and group will never know it.
1442 slice_used
= max_t(unsigned, (jiffies
- cfqq
->dispatch_start
),
1445 slice_used
= jiffies
- cfqq
->slice_start
;
1446 if (slice_used
> cfqq
->allocated_slice
) {
1447 *unaccounted_time
= slice_used
- cfqq
->allocated_slice
;
1448 slice_used
= cfqq
->allocated_slice
;
1450 if (time_after(cfqq
->slice_start
, cfqq
->dispatch_start
))
1451 *unaccounted_time
+= cfqq
->slice_start
-
1452 cfqq
->dispatch_start
;
1458 static void cfq_group_served(struct cfq_data
*cfqd
, struct cfq_group
*cfqg
,
1459 struct cfq_queue
*cfqq
)
1461 struct cfq_rb_root
*st
= &cfqd
->grp_service_tree
;
1462 unsigned int used_sl
, charge
, unaccounted_sl
= 0;
1463 int nr_sync
= cfqg
->nr_cfqq
- cfqg_busy_async_queues(cfqd
, cfqg
)
1464 - cfqg
->service_tree_idle
.count
;
1467 BUG_ON(nr_sync
< 0);
1468 used_sl
= charge
= cfq_cfqq_slice_usage(cfqq
, &unaccounted_sl
);
1470 if (iops_mode(cfqd
))
1471 charge
= cfqq
->slice_dispatch
;
1472 else if (!cfq_cfqq_sync(cfqq
) && !nr_sync
)
1473 charge
= cfqq
->allocated_slice
;
1476 * Can't update vdisktime while on service tree and cfqg->vfraction
1477 * is valid only while on it. Cache vfr, leave the service tree,
1478 * update vdisktime and go back on. The re-addition to the tree
1479 * will also update the weights as necessary.
1481 vfr
= cfqg
->vfraction
;
1482 cfq_group_service_tree_del(st
, cfqg
);
1483 cfqg
->vdisktime
+= cfqg_scale_charge(charge
, vfr
);
1484 cfq_group_service_tree_add(st
, cfqg
);
1486 /* This group is being expired. Save the context */
1487 if (time_after(cfqd
->workload_expires
, jiffies
)) {
1488 cfqg
->saved_wl_slice
= cfqd
->workload_expires
1490 cfqg
->saved_wl_type
= cfqd
->serving_wl_type
;
1491 cfqg
->saved_wl_class
= cfqd
->serving_wl_class
;
1493 cfqg
->saved_wl_slice
= 0;
1495 cfq_log_cfqg(cfqd
, cfqg
, "served: vt=%llu min_vt=%llu", cfqg
->vdisktime
,
1497 cfq_log_cfqq(cfqq
->cfqd
, cfqq
,
1498 "sl_used=%u disp=%u charge=%u iops=%u sect=%lu",
1499 used_sl
, cfqq
->slice_dispatch
, charge
,
1500 iops_mode(cfqd
), cfqq
->nr_sectors
);
1501 cfqg_stats_update_timeslice_used(cfqg
, used_sl
, unaccounted_sl
);
1502 cfqg_stats_set_start_empty_time(cfqg
);
1506 * cfq_init_cfqg_base - initialize base part of a cfq_group
1507 * @cfqg: cfq_group to initialize
1509 * Initialize the base part which is used whether %CONFIG_CFQ_GROUP_IOSCHED
1510 * is enabled or not.
1512 static void cfq_init_cfqg_base(struct cfq_group
*cfqg
)
1514 struct cfq_rb_root
*st
;
1517 for_each_cfqg_st(cfqg
, i
, j
, st
)
1519 RB_CLEAR_NODE(&cfqg
->rb_node
);
1521 cfqg
->ttime
.last_end_request
= jiffies
;
1524 #ifdef CONFIG_CFQ_GROUP_IOSCHED
1525 static void cfqg_stats_exit(struct cfqg_stats
*stats
)
1527 blkg_rwstat_exit(&stats
->merged
);
1528 blkg_rwstat_exit(&stats
->service_time
);
1529 blkg_rwstat_exit(&stats
->wait_time
);
1530 blkg_rwstat_exit(&stats
->queued
);
1531 blkg_stat_exit(&stats
->time
);
1532 #ifdef CONFIG_DEBUG_BLK_CGROUP
1533 blkg_stat_exit(&stats
->unaccounted_time
);
1534 blkg_stat_exit(&stats
->avg_queue_size_sum
);
1535 blkg_stat_exit(&stats
->avg_queue_size_samples
);
1536 blkg_stat_exit(&stats
->dequeue
);
1537 blkg_stat_exit(&stats
->group_wait_time
);
1538 blkg_stat_exit(&stats
->idle_time
);
1539 blkg_stat_exit(&stats
->empty_time
);
1543 static int cfqg_stats_init(struct cfqg_stats
*stats
, gfp_t gfp
)
1545 if (blkg_rwstat_init(&stats
->merged
, gfp
) ||
1546 blkg_rwstat_init(&stats
->service_time
, gfp
) ||
1547 blkg_rwstat_init(&stats
->wait_time
, gfp
) ||
1548 blkg_rwstat_init(&stats
->queued
, gfp
) ||
1549 blkg_stat_init(&stats
->time
, gfp
))
1552 #ifdef CONFIG_DEBUG_BLK_CGROUP
1553 if (blkg_stat_init(&stats
->unaccounted_time
, gfp
) ||
1554 blkg_stat_init(&stats
->avg_queue_size_sum
, gfp
) ||
1555 blkg_stat_init(&stats
->avg_queue_size_samples
, gfp
) ||
1556 blkg_stat_init(&stats
->dequeue
, gfp
) ||
1557 blkg_stat_init(&stats
->group_wait_time
, gfp
) ||
1558 blkg_stat_init(&stats
->idle_time
, gfp
) ||
1559 blkg_stat_init(&stats
->empty_time
, gfp
))
1564 cfqg_stats_exit(stats
);
1568 static struct blkcg_policy_data
*cfq_cpd_alloc(gfp_t gfp
)
1570 struct cfq_group_data
*cgd
;
1572 cgd
= kzalloc(sizeof(*cgd
), GFP_KERNEL
);
1578 static void cfq_cpd_init(struct blkcg_policy_data
*cpd
)
1580 struct cfq_group_data
*cgd
= cpd_to_cfqgd(cpd
);
1582 if (cpd_to_blkcg(cpd
) == &blkcg_root
) {
1583 cgd
->weight
= 2 * CFQ_WEIGHT_DEFAULT
;
1584 cgd
->leaf_weight
= 2 * CFQ_WEIGHT_DEFAULT
;
1586 cgd
->weight
= CFQ_WEIGHT_DEFAULT
;
1587 cgd
->leaf_weight
= CFQ_WEIGHT_DEFAULT
;
1591 static void cfq_cpd_free(struct blkcg_policy_data
*cpd
)
1593 kfree(cpd_to_cfqgd(cpd
));
1596 static struct blkg_policy_data
*cfq_pd_alloc(gfp_t gfp
, int node
)
1598 struct cfq_group
*cfqg
;
1600 cfqg
= kzalloc_node(sizeof(*cfqg
), gfp
, node
);
1604 cfq_init_cfqg_base(cfqg
);
1605 if (cfqg_stats_init(&cfqg
->stats
, gfp
)) {
1613 static void cfq_pd_init(struct blkg_policy_data
*pd
)
1615 struct cfq_group
*cfqg
= pd_to_cfqg(pd
);
1616 struct cfq_group_data
*cgd
= blkcg_to_cfqgd(pd
->blkg
->blkcg
);
1618 cfqg
->weight
= cgd
->weight
;
1619 cfqg
->leaf_weight
= cgd
->leaf_weight
;
1622 static void cfq_pd_offline(struct blkg_policy_data
*pd
)
1624 struct cfq_group
*cfqg
= pd_to_cfqg(pd
);
1627 for (i
= 0; i
< IOPRIO_BE_NR
; i
++) {
1628 if (cfqg
->async_cfqq
[0][i
])
1629 cfq_put_queue(cfqg
->async_cfqq
[0][i
]);
1630 if (cfqg
->async_cfqq
[1][i
])
1631 cfq_put_queue(cfqg
->async_cfqq
[1][i
]);
1634 if (cfqg
->async_idle_cfqq
)
1635 cfq_put_queue(cfqg
->async_idle_cfqq
);
1638 * @blkg is going offline and will be ignored by
1639 * blkg_[rw]stat_recursive_sum(). Transfer stats to the parent so
1640 * that they don't get lost. If IOs complete after this point, the
1641 * stats for them will be lost. Oh well...
1643 cfqg_stats_xfer_dead(cfqg
);
1646 static void cfq_pd_free(struct blkg_policy_data
*pd
)
1648 struct cfq_group
*cfqg
= pd_to_cfqg(pd
);
1650 cfqg_stats_exit(&cfqg
->stats
);
1654 static void cfq_pd_reset_stats(struct blkg_policy_data
*pd
)
1656 struct cfq_group
*cfqg
= pd_to_cfqg(pd
);
1658 cfqg_stats_reset(&cfqg
->stats
);
1661 static struct cfq_group
*cfq_lookup_cfqg(struct cfq_data
*cfqd
,
1662 struct blkcg
*blkcg
)
1664 struct blkcg_gq
*blkg
;
1666 blkg
= blkg_lookup(blkcg
, cfqd
->queue
);
1668 return blkg_to_cfqg(blkg
);
1672 static void cfq_link_cfqq_cfqg(struct cfq_queue
*cfqq
, struct cfq_group
*cfqg
)
1675 /* cfqq reference on cfqg */
1679 static u64
cfqg_prfill_weight_device(struct seq_file
*sf
,
1680 struct blkg_policy_data
*pd
, int off
)
1682 struct cfq_group
*cfqg
= pd_to_cfqg(pd
);
1684 if (!cfqg
->dev_weight
)
1686 return __blkg_prfill_u64(sf
, pd
, cfqg
->dev_weight
);
1689 static int cfqg_print_weight_device(struct seq_file
*sf
, void *v
)
1691 blkcg_print_blkgs(sf
, css_to_blkcg(seq_css(sf
)),
1692 cfqg_prfill_weight_device
, &blkcg_policy_cfq
,
1697 static u64
cfqg_prfill_leaf_weight_device(struct seq_file
*sf
,
1698 struct blkg_policy_data
*pd
, int off
)
1700 struct cfq_group
*cfqg
= pd_to_cfqg(pd
);
1702 if (!cfqg
->dev_leaf_weight
)
1704 return __blkg_prfill_u64(sf
, pd
, cfqg
->dev_leaf_weight
);
1707 static int cfqg_print_leaf_weight_device(struct seq_file
*sf
, void *v
)
1709 blkcg_print_blkgs(sf
, css_to_blkcg(seq_css(sf
)),
1710 cfqg_prfill_leaf_weight_device
, &blkcg_policy_cfq
,
1715 static int cfq_print_weight(struct seq_file
*sf
, void *v
)
1717 struct blkcg
*blkcg
= css_to_blkcg(seq_css(sf
));
1718 struct cfq_group_data
*cgd
= blkcg_to_cfqgd(blkcg
);
1719 unsigned int val
= 0;
1724 seq_printf(sf
, "%u\n", val
);
1728 static int cfq_print_leaf_weight(struct seq_file
*sf
, void *v
)
1730 struct blkcg
*blkcg
= css_to_blkcg(seq_css(sf
));
1731 struct cfq_group_data
*cgd
= blkcg_to_cfqgd(blkcg
);
1732 unsigned int val
= 0;
1735 val
= cgd
->leaf_weight
;
1737 seq_printf(sf
, "%u\n", val
);
1741 static ssize_t
__cfqg_set_weight_device(struct kernfs_open_file
*of
,
1742 char *buf
, size_t nbytes
, loff_t off
,
1743 bool is_leaf_weight
)
1745 struct blkcg
*blkcg
= css_to_blkcg(of_css(of
));
1746 struct blkg_conf_ctx ctx
;
1747 struct cfq_group
*cfqg
;
1748 struct cfq_group_data
*cfqgd
;
1751 ret
= blkg_conf_prep(blkcg
, &blkcg_policy_cfq
, buf
, &ctx
);
1755 cfqg
= blkg_to_cfqg(ctx
.blkg
);
1756 cfqgd
= blkcg_to_cfqgd(blkcg
);
1759 if (!ctx
.v
|| (ctx
.v
>= CFQ_WEIGHT_MIN
&& ctx
.v
<= CFQ_WEIGHT_MAX
)) {
1760 if (!is_leaf_weight
) {
1761 cfqg
->dev_weight
= ctx
.v
;
1762 cfqg
->new_weight
= ctx
.v
?: cfqgd
->weight
;
1764 cfqg
->dev_leaf_weight
= ctx
.v
;
1765 cfqg
->new_leaf_weight
= ctx
.v
?: cfqgd
->leaf_weight
;
1770 blkg_conf_finish(&ctx
);
1771 return ret
?: nbytes
;
1774 static ssize_t
cfqg_set_weight_device(struct kernfs_open_file
*of
,
1775 char *buf
, size_t nbytes
, loff_t off
)
1777 return __cfqg_set_weight_device(of
, buf
, nbytes
, off
, false);
1780 static ssize_t
cfqg_set_leaf_weight_device(struct kernfs_open_file
*of
,
1781 char *buf
, size_t nbytes
, loff_t off
)
1783 return __cfqg_set_weight_device(of
, buf
, nbytes
, off
, true);
1786 static int __cfq_set_weight(struct cgroup_subsys_state
*css
, struct cftype
*cft
,
1787 u64 val
, bool is_leaf_weight
)
1789 struct blkcg
*blkcg
= css_to_blkcg(css
);
1790 struct blkcg_gq
*blkg
;
1791 struct cfq_group_data
*cfqgd
;
1794 if (val
< CFQ_WEIGHT_MIN
|| val
> CFQ_WEIGHT_MAX
)
1797 spin_lock_irq(&blkcg
->lock
);
1798 cfqgd
= blkcg_to_cfqgd(blkcg
);
1804 if (!is_leaf_weight
)
1805 cfqgd
->weight
= val
;
1807 cfqgd
->leaf_weight
= val
;
1809 hlist_for_each_entry(blkg
, &blkcg
->blkg_list
, blkcg_node
) {
1810 struct cfq_group
*cfqg
= blkg_to_cfqg(blkg
);
1815 if (!is_leaf_weight
) {
1816 if (!cfqg
->dev_weight
)
1817 cfqg
->new_weight
= cfqgd
->weight
;
1819 if (!cfqg
->dev_leaf_weight
)
1820 cfqg
->new_leaf_weight
= cfqgd
->leaf_weight
;
1825 spin_unlock_irq(&blkcg
->lock
);
1829 static int cfq_set_weight(struct cgroup_subsys_state
*css
, struct cftype
*cft
,
1832 return __cfq_set_weight(css
, cft
, val
, false);
1835 static int cfq_set_leaf_weight(struct cgroup_subsys_state
*css
,
1836 struct cftype
*cft
, u64 val
)
1838 return __cfq_set_weight(css
, cft
, val
, true);
1841 static int cfqg_print_stat(struct seq_file
*sf
, void *v
)
1843 blkcg_print_blkgs(sf
, css_to_blkcg(seq_css(sf
)), blkg_prfill_stat
,
1844 &blkcg_policy_cfq
, seq_cft(sf
)->private, false);
1848 static int cfqg_print_rwstat(struct seq_file
*sf
, void *v
)
1850 blkcg_print_blkgs(sf
, css_to_blkcg(seq_css(sf
)), blkg_prfill_rwstat
,
1851 &blkcg_policy_cfq
, seq_cft(sf
)->private, true);
1855 static u64
cfqg_prfill_stat_recursive(struct seq_file
*sf
,
1856 struct blkg_policy_data
*pd
, int off
)
1858 u64 sum
= blkg_stat_recursive_sum(pd_to_blkg(pd
),
1859 &blkcg_policy_cfq
, off
);
1860 return __blkg_prfill_u64(sf
, pd
, sum
);
1863 static u64
cfqg_prfill_rwstat_recursive(struct seq_file
*sf
,
1864 struct blkg_policy_data
*pd
, int off
)
1866 struct blkg_rwstat sum
= blkg_rwstat_recursive_sum(pd_to_blkg(pd
),
1867 &blkcg_policy_cfq
, off
);
1868 return __blkg_prfill_rwstat(sf
, pd
, &sum
);
1871 static int cfqg_print_stat_recursive(struct seq_file
*sf
, void *v
)
1873 blkcg_print_blkgs(sf
, css_to_blkcg(seq_css(sf
)),
1874 cfqg_prfill_stat_recursive
, &blkcg_policy_cfq
,
1875 seq_cft(sf
)->private, false);
1879 static int cfqg_print_rwstat_recursive(struct seq_file
*sf
, void *v
)
1881 blkcg_print_blkgs(sf
, css_to_blkcg(seq_css(sf
)),
1882 cfqg_prfill_rwstat_recursive
, &blkcg_policy_cfq
,
1883 seq_cft(sf
)->private, true);
1887 static u64
cfqg_prfill_sectors(struct seq_file
*sf
, struct blkg_policy_data
*pd
,
1890 u64 sum
= blkg_rwstat_total(&pd
->blkg
->stat_bytes
);
1892 return __blkg_prfill_u64(sf
, pd
, sum
>> 9);
1895 static int cfqg_print_stat_sectors(struct seq_file
*sf
, void *v
)
1897 blkcg_print_blkgs(sf
, css_to_blkcg(seq_css(sf
)),
1898 cfqg_prfill_sectors
, &blkcg_policy_cfq
, 0, false);
1902 static u64
cfqg_prfill_sectors_recursive(struct seq_file
*sf
,
1903 struct blkg_policy_data
*pd
, int off
)
1905 struct blkg_rwstat tmp
= blkg_rwstat_recursive_sum(pd
->blkg
, NULL
,
1906 offsetof(struct blkcg_gq
, stat_bytes
));
1907 u64 sum
= atomic64_read(&tmp
.aux_cnt
[BLKG_RWSTAT_READ
]) +
1908 atomic64_read(&tmp
.aux_cnt
[BLKG_RWSTAT_WRITE
]);
1910 return __blkg_prfill_u64(sf
, pd
, sum
>> 9);
1913 static int cfqg_print_stat_sectors_recursive(struct seq_file
*sf
, void *v
)
1915 blkcg_print_blkgs(sf
, css_to_blkcg(seq_css(sf
)),
1916 cfqg_prfill_sectors_recursive
, &blkcg_policy_cfq
, 0,
1921 #ifdef CONFIG_DEBUG_BLK_CGROUP
1922 static u64
cfqg_prfill_avg_queue_size(struct seq_file
*sf
,
1923 struct blkg_policy_data
*pd
, int off
)
1925 struct cfq_group
*cfqg
= pd_to_cfqg(pd
);
1926 u64 samples
= blkg_stat_read(&cfqg
->stats
.avg_queue_size_samples
);
1930 v
= blkg_stat_read(&cfqg
->stats
.avg_queue_size_sum
);
1931 v
= div64_u64(v
, samples
);
1933 __blkg_prfill_u64(sf
, pd
, v
);
1937 /* print avg_queue_size */
1938 static int cfqg_print_avg_queue_size(struct seq_file
*sf
, void *v
)
1940 blkcg_print_blkgs(sf
, css_to_blkcg(seq_css(sf
)),
1941 cfqg_prfill_avg_queue_size
, &blkcg_policy_cfq
,
1945 #endif /* CONFIG_DEBUG_BLK_CGROUP */
1947 static struct cftype cfq_blkcg_files
[] = {
1948 /* on root, weight is mapped to leaf_weight */
1950 .name
= "weight_device",
1951 .flags
= CFTYPE_ONLY_ON_ROOT
,
1952 .seq_show
= cfqg_print_leaf_weight_device
,
1953 .write
= cfqg_set_leaf_weight_device
,
1957 .flags
= CFTYPE_ONLY_ON_ROOT
,
1958 .seq_show
= cfq_print_leaf_weight
,
1959 .write_u64
= cfq_set_leaf_weight
,
1962 /* no such mapping necessary for !roots */
1964 .name
= "weight_device",
1965 .flags
= CFTYPE_NOT_ON_ROOT
,
1966 .seq_show
= cfqg_print_weight_device
,
1967 .write
= cfqg_set_weight_device
,
1971 .flags
= CFTYPE_NOT_ON_ROOT
,
1972 .seq_show
= cfq_print_weight
,
1973 .write_u64
= cfq_set_weight
,
1977 .name
= "leaf_weight_device",
1978 .seq_show
= cfqg_print_leaf_weight_device
,
1979 .write
= cfqg_set_leaf_weight_device
,
1982 .name
= "leaf_weight",
1983 .seq_show
= cfq_print_leaf_weight
,
1984 .write_u64
= cfq_set_leaf_weight
,
1987 /* statistics, covers only the tasks in the cfqg */
1990 .private = offsetof(struct cfq_group
, stats
.time
),
1991 .seq_show
= cfqg_print_stat
,
1995 .seq_show
= cfqg_print_stat_sectors
,
1998 .name
= "io_service_bytes",
1999 .private = (unsigned long)&blkcg_policy_cfq
,
2000 .seq_show
= blkg_print_stat_bytes
,
2003 .name
= "io_serviced",
2004 .private = (unsigned long)&blkcg_policy_cfq
,
2005 .seq_show
= blkg_print_stat_ios
,
2008 .name
= "io_service_time",
2009 .private = offsetof(struct cfq_group
, stats
.service_time
),
2010 .seq_show
= cfqg_print_rwstat
,
2013 .name
= "io_wait_time",
2014 .private = offsetof(struct cfq_group
, stats
.wait_time
),
2015 .seq_show
= cfqg_print_rwstat
,
2018 .name
= "io_merged",
2019 .private = offsetof(struct cfq_group
, stats
.merged
),
2020 .seq_show
= cfqg_print_rwstat
,
2023 .name
= "io_queued",
2024 .private = offsetof(struct cfq_group
, stats
.queued
),
2025 .seq_show
= cfqg_print_rwstat
,
2028 /* the same statictics which cover the cfqg and its descendants */
2030 .name
= "time_recursive",
2031 .private = offsetof(struct cfq_group
, stats
.time
),
2032 .seq_show
= cfqg_print_stat_recursive
,
2035 .name
= "sectors_recursive",
2036 .seq_show
= cfqg_print_stat_sectors_recursive
,
2039 .name
= "io_service_bytes_recursive",
2040 .private = (unsigned long)&blkcg_policy_cfq
,
2041 .seq_show
= blkg_print_stat_bytes_recursive
,
2044 .name
= "io_serviced_recursive",
2045 .private = (unsigned long)&blkcg_policy_cfq
,
2046 .seq_show
= blkg_print_stat_ios_recursive
,
2049 .name
= "io_service_time_recursive",
2050 .private = offsetof(struct cfq_group
, stats
.service_time
),
2051 .seq_show
= cfqg_print_rwstat_recursive
,
2054 .name
= "io_wait_time_recursive",
2055 .private = offsetof(struct cfq_group
, stats
.wait_time
),
2056 .seq_show
= cfqg_print_rwstat_recursive
,
2059 .name
= "io_merged_recursive",
2060 .private = offsetof(struct cfq_group
, stats
.merged
),
2061 .seq_show
= cfqg_print_rwstat_recursive
,
2064 .name
= "io_queued_recursive",
2065 .private = offsetof(struct cfq_group
, stats
.queued
),
2066 .seq_show
= cfqg_print_rwstat_recursive
,
2068 #ifdef CONFIG_DEBUG_BLK_CGROUP
2070 .name
= "avg_queue_size",
2071 .seq_show
= cfqg_print_avg_queue_size
,
2074 .name
= "group_wait_time",
2075 .private = offsetof(struct cfq_group
, stats
.group_wait_time
),
2076 .seq_show
= cfqg_print_stat
,
2079 .name
= "idle_time",
2080 .private = offsetof(struct cfq_group
, stats
.idle_time
),
2081 .seq_show
= cfqg_print_stat
,
2084 .name
= "empty_time",
2085 .private = offsetof(struct cfq_group
, stats
.empty_time
),
2086 .seq_show
= cfqg_print_stat
,
2090 .private = offsetof(struct cfq_group
, stats
.dequeue
),
2091 .seq_show
= cfqg_print_stat
,
2094 .name
= "unaccounted_time",
2095 .private = offsetof(struct cfq_group
, stats
.unaccounted_time
),
2096 .seq_show
= cfqg_print_stat
,
2098 #endif /* CONFIG_DEBUG_BLK_CGROUP */
2101 #else /* GROUP_IOSCHED */
2102 static struct cfq_group
*cfq_lookup_cfqg(struct cfq_data
*cfqd
,
2103 struct blkcg
*blkcg
)
2105 return cfqd
->root_group
;
2109 cfq_link_cfqq_cfqg(struct cfq_queue
*cfqq
, struct cfq_group
*cfqg
) {
2113 #endif /* GROUP_IOSCHED */
2116 * The cfqd->service_trees holds all pending cfq_queue's that have
2117 * requests waiting to be processed. It is sorted in the order that
2118 * we will service the queues.
2120 static void cfq_service_tree_add(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
2123 struct rb_node
**p
, *parent
;
2124 struct cfq_queue
*__cfqq
;
2125 unsigned long rb_key
;
2126 struct cfq_rb_root
*st
;
2130 st
= st_for(cfqq
->cfqg
, cfqq_class(cfqq
), cfqq_type(cfqq
));
2131 if (cfq_class_idle(cfqq
)) {
2132 rb_key
= CFQ_IDLE_DELAY
;
2133 parent
= rb_last(&st
->rb
);
2134 if (parent
&& parent
!= &cfqq
->rb_node
) {
2135 __cfqq
= rb_entry(parent
, struct cfq_queue
, rb_node
);
2136 rb_key
+= __cfqq
->rb_key
;
2139 } else if (!add_front
) {
2141 * Get our rb key offset. Subtract any residual slice
2142 * value carried from last service. A negative resid
2143 * count indicates slice overrun, and this should position
2144 * the next service time further away in the tree.
2146 rb_key
= cfq_slice_offset(cfqd
, cfqq
) + jiffies
;
2147 rb_key
-= cfqq
->slice_resid
;
2148 cfqq
->slice_resid
= 0;
2151 __cfqq
= cfq_rb_first(st
);
2152 rb_key
+= __cfqq
? __cfqq
->rb_key
: jiffies
;
2155 if (!RB_EMPTY_NODE(&cfqq
->rb_node
)) {
2158 * same position, nothing more to do
2160 if (rb_key
== cfqq
->rb_key
&& cfqq
->service_tree
== st
)
2163 cfq_rb_erase(&cfqq
->rb_node
, cfqq
->service_tree
);
2164 cfqq
->service_tree
= NULL
;
2169 cfqq
->service_tree
= st
;
2170 p
= &st
->rb
.rb_node
;
2173 __cfqq
= rb_entry(parent
, struct cfq_queue
, rb_node
);
2176 * sort by key, that represents service time.
2178 if (time_before(rb_key
, __cfqq
->rb_key
))
2179 p
= &parent
->rb_left
;
2181 p
= &parent
->rb_right
;
2187 st
->left
= &cfqq
->rb_node
;
2189 cfqq
->rb_key
= rb_key
;
2190 rb_link_node(&cfqq
->rb_node
, parent
, p
);
2191 rb_insert_color(&cfqq
->rb_node
, &st
->rb
);
2193 if (add_front
|| !new_cfqq
)
2195 cfq_group_notify_queue_add(cfqd
, cfqq
->cfqg
);
2198 static struct cfq_queue
*
2199 cfq_prio_tree_lookup(struct cfq_data
*cfqd
, struct rb_root
*root
,
2200 sector_t sector
, struct rb_node
**ret_parent
,
2201 struct rb_node
***rb_link
)
2203 struct rb_node
**p
, *parent
;
2204 struct cfq_queue
*cfqq
= NULL
;
2212 cfqq
= rb_entry(parent
, struct cfq_queue
, p_node
);
2215 * Sort strictly based on sector. Smallest to the left,
2216 * largest to the right.
2218 if (sector
> blk_rq_pos(cfqq
->next_rq
))
2219 n
= &(*p
)->rb_right
;
2220 else if (sector
< blk_rq_pos(cfqq
->next_rq
))
2228 *ret_parent
= parent
;
2234 static void cfq_prio_tree_add(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
2236 struct rb_node
**p
, *parent
;
2237 struct cfq_queue
*__cfqq
;
2240 rb_erase(&cfqq
->p_node
, cfqq
->p_root
);
2241 cfqq
->p_root
= NULL
;
2244 if (cfq_class_idle(cfqq
))
2249 cfqq
->p_root
= &cfqd
->prio_trees
[cfqq
->org_ioprio
];
2250 __cfqq
= cfq_prio_tree_lookup(cfqd
, cfqq
->p_root
,
2251 blk_rq_pos(cfqq
->next_rq
), &parent
, &p
);
2253 rb_link_node(&cfqq
->p_node
, parent
, p
);
2254 rb_insert_color(&cfqq
->p_node
, cfqq
->p_root
);
2256 cfqq
->p_root
= NULL
;
2260 * Update cfqq's position in the service tree.
2262 static void cfq_resort_rr_list(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
2265 * Resorting requires the cfqq to be on the RR list already.
2267 if (cfq_cfqq_on_rr(cfqq
)) {
2268 cfq_service_tree_add(cfqd
, cfqq
, 0);
2269 cfq_prio_tree_add(cfqd
, cfqq
);
2274 * add to busy list of queues for service, trying to be fair in ordering
2275 * the pending list according to last request service
2277 static void cfq_add_cfqq_rr(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
2279 cfq_log_cfqq(cfqd
, cfqq
, "add_to_rr");
2280 BUG_ON(cfq_cfqq_on_rr(cfqq
));
2281 cfq_mark_cfqq_on_rr(cfqq
);
2282 cfqd
->busy_queues
++;
2283 if (cfq_cfqq_sync(cfqq
))
2284 cfqd
->busy_sync_queues
++;
2286 cfq_resort_rr_list(cfqd
, cfqq
);
2290 * Called when the cfqq no longer has requests pending, remove it from
2293 static void cfq_del_cfqq_rr(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
2295 cfq_log_cfqq(cfqd
, cfqq
, "del_from_rr");
2296 BUG_ON(!cfq_cfqq_on_rr(cfqq
));
2297 cfq_clear_cfqq_on_rr(cfqq
);
2299 if (!RB_EMPTY_NODE(&cfqq
->rb_node
)) {
2300 cfq_rb_erase(&cfqq
->rb_node
, cfqq
->service_tree
);
2301 cfqq
->service_tree
= NULL
;
2304 rb_erase(&cfqq
->p_node
, cfqq
->p_root
);
2305 cfqq
->p_root
= NULL
;
2308 cfq_group_notify_queue_del(cfqd
, cfqq
->cfqg
);
2309 BUG_ON(!cfqd
->busy_queues
);
2310 cfqd
->busy_queues
--;
2311 if (cfq_cfqq_sync(cfqq
))
2312 cfqd
->busy_sync_queues
--;
2316 * rb tree support functions
2318 static void cfq_del_rq_rb(struct request
*rq
)
2320 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
2321 const int sync
= rq_is_sync(rq
);
2323 BUG_ON(!cfqq
->queued
[sync
]);
2324 cfqq
->queued
[sync
]--;
2326 elv_rb_del(&cfqq
->sort_list
, rq
);
2328 if (cfq_cfqq_on_rr(cfqq
) && RB_EMPTY_ROOT(&cfqq
->sort_list
)) {
2330 * Queue will be deleted from service tree when we actually
2331 * expire it later. Right now just remove it from prio tree
2335 rb_erase(&cfqq
->p_node
, cfqq
->p_root
);
2336 cfqq
->p_root
= NULL
;
2341 static void cfq_add_rq_rb(struct request
*rq
)
2343 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
2344 struct cfq_data
*cfqd
= cfqq
->cfqd
;
2345 struct request
*prev
;
2347 cfqq
->queued
[rq_is_sync(rq
)]++;
2349 elv_rb_add(&cfqq
->sort_list
, rq
);
2351 if (!cfq_cfqq_on_rr(cfqq
))
2352 cfq_add_cfqq_rr(cfqd
, cfqq
);
2355 * check if this request is a better next-serve candidate
2357 prev
= cfqq
->next_rq
;
2358 cfqq
->next_rq
= cfq_choose_req(cfqd
, cfqq
->next_rq
, rq
, cfqd
->last_position
);
2361 * adjust priority tree position, if ->next_rq changes
2363 if (prev
!= cfqq
->next_rq
)
2364 cfq_prio_tree_add(cfqd
, cfqq
);
2366 BUG_ON(!cfqq
->next_rq
);
2369 static void cfq_reposition_rq_rb(struct cfq_queue
*cfqq
, struct request
*rq
)
2371 elv_rb_del(&cfqq
->sort_list
, rq
);
2372 cfqq
->queued
[rq_is_sync(rq
)]--;
2373 cfqg_stats_update_io_remove(RQ_CFQG(rq
), rq
->cmd_flags
);
2375 cfqg_stats_update_io_add(RQ_CFQG(rq
), cfqq
->cfqd
->serving_group
,
2379 static struct request
*
2380 cfq_find_rq_fmerge(struct cfq_data
*cfqd
, struct bio
*bio
)
2382 struct task_struct
*tsk
= current
;
2383 struct cfq_io_cq
*cic
;
2384 struct cfq_queue
*cfqq
;
2386 cic
= cfq_cic_lookup(cfqd
, tsk
->io_context
);
2390 cfqq
= cic_to_cfqq(cic
, cfq_bio_sync(bio
));
2392 return elv_rb_find(&cfqq
->sort_list
, bio_end_sector(bio
));
2397 static void cfq_activate_request(struct request_queue
*q
, struct request
*rq
)
2399 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
2401 cfqd
->rq_in_driver
++;
2402 cfq_log_cfqq(cfqd
, RQ_CFQQ(rq
), "activate rq, drv=%d",
2403 cfqd
->rq_in_driver
);
2405 cfqd
->last_position
= blk_rq_pos(rq
) + blk_rq_sectors(rq
);
2408 static void cfq_deactivate_request(struct request_queue
*q
, struct request
*rq
)
2410 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
2412 WARN_ON(!cfqd
->rq_in_driver
);
2413 cfqd
->rq_in_driver
--;
2414 cfq_log_cfqq(cfqd
, RQ_CFQQ(rq
), "deactivate rq, drv=%d",
2415 cfqd
->rq_in_driver
);
2418 static void cfq_remove_request(struct request
*rq
)
2420 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
2422 if (cfqq
->next_rq
== rq
)
2423 cfqq
->next_rq
= cfq_find_next_rq(cfqq
->cfqd
, cfqq
, rq
);
2425 list_del_init(&rq
->queuelist
);
2428 cfqq
->cfqd
->rq_queued
--;
2429 cfqg_stats_update_io_remove(RQ_CFQG(rq
), rq
->cmd_flags
);
2430 if (rq
->cmd_flags
& REQ_PRIO
) {
2431 WARN_ON(!cfqq
->prio_pending
);
2432 cfqq
->prio_pending
--;
2436 static int cfq_merge(struct request_queue
*q
, struct request
**req
,
2439 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
2440 struct request
*__rq
;
2442 __rq
= cfq_find_rq_fmerge(cfqd
, bio
);
2443 if (__rq
&& elv_rq_merge_ok(__rq
, bio
)) {
2445 return ELEVATOR_FRONT_MERGE
;
2448 return ELEVATOR_NO_MERGE
;
2451 static void cfq_merged_request(struct request_queue
*q
, struct request
*req
,
2454 if (type
== ELEVATOR_FRONT_MERGE
) {
2455 struct cfq_queue
*cfqq
= RQ_CFQQ(req
);
2457 cfq_reposition_rq_rb(cfqq
, req
);
2461 static void cfq_bio_merged(struct request_queue
*q
, struct request
*req
,
2464 cfqg_stats_update_io_merged(RQ_CFQG(req
), bio
->bi_rw
);
2468 cfq_merged_requests(struct request_queue
*q
, struct request
*rq
,
2469 struct request
*next
)
2471 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
2472 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
2475 * reposition in fifo if next is older than rq
2477 if (!list_empty(&rq
->queuelist
) && !list_empty(&next
->queuelist
) &&
2478 time_before(next
->fifo_time
, rq
->fifo_time
) &&
2479 cfqq
== RQ_CFQQ(next
)) {
2480 list_move(&rq
->queuelist
, &next
->queuelist
);
2481 rq
->fifo_time
= next
->fifo_time
;
2484 if (cfqq
->next_rq
== next
)
2486 cfq_remove_request(next
);
2487 cfqg_stats_update_io_merged(RQ_CFQG(rq
), next
->cmd_flags
);
2489 cfqq
= RQ_CFQQ(next
);
2491 * all requests of this queue are merged to other queues, delete it
2492 * from the service tree. If it's the active_queue,
2493 * cfq_dispatch_requests() will choose to expire it or do idle
2495 if (cfq_cfqq_on_rr(cfqq
) && RB_EMPTY_ROOT(&cfqq
->sort_list
) &&
2496 cfqq
!= cfqd
->active_queue
)
2497 cfq_del_cfqq_rr(cfqd
, cfqq
);
2500 static int cfq_allow_merge(struct request_queue
*q
, struct request
*rq
,
2503 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
2504 struct cfq_io_cq
*cic
;
2505 struct cfq_queue
*cfqq
;
2508 * Disallow merge of a sync bio into an async request.
2510 if (cfq_bio_sync(bio
) && !rq_is_sync(rq
))
2514 * Lookup the cfqq that this bio will be queued with and allow
2515 * merge only if rq is queued there.
2517 cic
= cfq_cic_lookup(cfqd
, current
->io_context
);
2521 cfqq
= cic_to_cfqq(cic
, cfq_bio_sync(bio
));
2522 return cfqq
== RQ_CFQQ(rq
);
2525 static inline void cfq_del_timer(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
2527 del_timer(&cfqd
->idle_slice_timer
);
2528 cfqg_stats_update_idle_time(cfqq
->cfqg
);
2531 static void __cfq_set_active_queue(struct cfq_data
*cfqd
,
2532 struct cfq_queue
*cfqq
)
2535 cfq_log_cfqq(cfqd
, cfqq
, "set_active wl_class:%d wl_type:%d",
2536 cfqd
->serving_wl_class
, cfqd
->serving_wl_type
);
2537 cfqg_stats_update_avg_queue_size(cfqq
->cfqg
);
2538 cfqq
->slice_start
= 0;
2539 cfqq
->dispatch_start
= jiffies
;
2540 cfqq
->allocated_slice
= 0;
2541 cfqq
->slice_end
= 0;
2542 cfqq
->slice_dispatch
= 0;
2543 cfqq
->nr_sectors
= 0;
2545 cfq_clear_cfqq_wait_request(cfqq
);
2546 cfq_clear_cfqq_must_dispatch(cfqq
);
2547 cfq_clear_cfqq_must_alloc_slice(cfqq
);
2548 cfq_clear_cfqq_fifo_expire(cfqq
);
2549 cfq_mark_cfqq_slice_new(cfqq
);
2551 cfq_del_timer(cfqd
, cfqq
);
2554 cfqd
->active_queue
= cfqq
;
2558 * current cfqq expired its slice (or was too idle), select new one
2561 __cfq_slice_expired(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
2564 cfq_log_cfqq(cfqd
, cfqq
, "slice expired t=%d", timed_out
);
2566 if (cfq_cfqq_wait_request(cfqq
))
2567 cfq_del_timer(cfqd
, cfqq
);
2569 cfq_clear_cfqq_wait_request(cfqq
);
2570 cfq_clear_cfqq_wait_busy(cfqq
);
2573 * If this cfqq is shared between multiple processes, check to
2574 * make sure that those processes are still issuing I/Os within
2575 * the mean seek distance. If not, it may be time to break the
2576 * queues apart again.
2578 if (cfq_cfqq_coop(cfqq
) && CFQQ_SEEKY(cfqq
))
2579 cfq_mark_cfqq_split_coop(cfqq
);
2582 * store what was left of this slice, if the queue idled/timed out
2585 if (cfq_cfqq_slice_new(cfqq
))
2586 cfqq
->slice_resid
= cfq_scaled_cfqq_slice(cfqd
, cfqq
);
2588 cfqq
->slice_resid
= cfqq
->slice_end
- jiffies
;
2589 cfq_log_cfqq(cfqd
, cfqq
, "resid=%ld", cfqq
->slice_resid
);
2592 cfq_group_served(cfqd
, cfqq
->cfqg
, cfqq
);
2594 if (cfq_cfqq_on_rr(cfqq
) && RB_EMPTY_ROOT(&cfqq
->sort_list
))
2595 cfq_del_cfqq_rr(cfqd
, cfqq
);
2597 cfq_resort_rr_list(cfqd
, cfqq
);
2599 if (cfqq
== cfqd
->active_queue
)
2600 cfqd
->active_queue
= NULL
;
2602 if (cfqd
->active_cic
) {
2603 put_io_context(cfqd
->active_cic
->icq
.ioc
);
2604 cfqd
->active_cic
= NULL
;
2608 static inline void cfq_slice_expired(struct cfq_data
*cfqd
, bool timed_out
)
2610 struct cfq_queue
*cfqq
= cfqd
->active_queue
;
2613 __cfq_slice_expired(cfqd
, cfqq
, timed_out
);
2617 * Get next queue for service. Unless we have a queue preemption,
2618 * we'll simply select the first cfqq in the service tree.
2620 static struct cfq_queue
*cfq_get_next_queue(struct cfq_data
*cfqd
)
2622 struct cfq_rb_root
*st
= st_for(cfqd
->serving_group
,
2623 cfqd
->serving_wl_class
, cfqd
->serving_wl_type
);
2625 if (!cfqd
->rq_queued
)
2628 /* There is nothing to dispatch */
2631 if (RB_EMPTY_ROOT(&st
->rb
))
2633 return cfq_rb_first(st
);
2636 static struct cfq_queue
*cfq_get_next_queue_forced(struct cfq_data
*cfqd
)
2638 struct cfq_group
*cfqg
;
2639 struct cfq_queue
*cfqq
;
2641 struct cfq_rb_root
*st
;
2643 if (!cfqd
->rq_queued
)
2646 cfqg
= cfq_get_next_cfqg(cfqd
);
2650 for_each_cfqg_st(cfqg
, i
, j
, st
)
2651 if ((cfqq
= cfq_rb_first(st
)) != NULL
)
2657 * Get and set a new active queue for service.
2659 static struct cfq_queue
*cfq_set_active_queue(struct cfq_data
*cfqd
,
2660 struct cfq_queue
*cfqq
)
2663 cfqq
= cfq_get_next_queue(cfqd
);
2665 __cfq_set_active_queue(cfqd
, cfqq
);
2669 static inline sector_t
cfq_dist_from_last(struct cfq_data
*cfqd
,
2672 if (blk_rq_pos(rq
) >= cfqd
->last_position
)
2673 return blk_rq_pos(rq
) - cfqd
->last_position
;
2675 return cfqd
->last_position
- blk_rq_pos(rq
);
2678 static inline int cfq_rq_close(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
2681 return cfq_dist_from_last(cfqd
, rq
) <= CFQQ_CLOSE_THR
;
2684 static struct cfq_queue
*cfqq_close(struct cfq_data
*cfqd
,
2685 struct cfq_queue
*cur_cfqq
)
2687 struct rb_root
*root
= &cfqd
->prio_trees
[cur_cfqq
->org_ioprio
];
2688 struct rb_node
*parent
, *node
;
2689 struct cfq_queue
*__cfqq
;
2690 sector_t sector
= cfqd
->last_position
;
2692 if (RB_EMPTY_ROOT(root
))
2696 * First, if we find a request starting at the end of the last
2697 * request, choose it.
2699 __cfqq
= cfq_prio_tree_lookup(cfqd
, root
, sector
, &parent
, NULL
);
2704 * If the exact sector wasn't found, the parent of the NULL leaf
2705 * will contain the closest sector.
2707 __cfqq
= rb_entry(parent
, struct cfq_queue
, p_node
);
2708 if (cfq_rq_close(cfqd
, cur_cfqq
, __cfqq
->next_rq
))
2711 if (blk_rq_pos(__cfqq
->next_rq
) < sector
)
2712 node
= rb_next(&__cfqq
->p_node
);
2714 node
= rb_prev(&__cfqq
->p_node
);
2718 __cfqq
= rb_entry(node
, struct cfq_queue
, p_node
);
2719 if (cfq_rq_close(cfqd
, cur_cfqq
, __cfqq
->next_rq
))
2727 * cur_cfqq - passed in so that we don't decide that the current queue is
2728 * closely cooperating with itself.
2730 * So, basically we're assuming that that cur_cfqq has dispatched at least
2731 * one request, and that cfqd->last_position reflects a position on the disk
2732 * associated with the I/O issued by cur_cfqq. I'm not sure this is a valid
2735 static struct cfq_queue
*cfq_close_cooperator(struct cfq_data
*cfqd
,
2736 struct cfq_queue
*cur_cfqq
)
2738 struct cfq_queue
*cfqq
;
2740 if (cfq_class_idle(cur_cfqq
))
2742 if (!cfq_cfqq_sync(cur_cfqq
))
2744 if (CFQQ_SEEKY(cur_cfqq
))
2748 * Don't search priority tree if it's the only queue in the group.
2750 if (cur_cfqq
->cfqg
->nr_cfqq
== 1)
2754 * We should notice if some of the queues are cooperating, eg
2755 * working closely on the same area of the disk. In that case,
2756 * we can group them together and don't waste time idling.
2758 cfqq
= cfqq_close(cfqd
, cur_cfqq
);
2762 /* If new queue belongs to different cfq_group, don't choose it */
2763 if (cur_cfqq
->cfqg
!= cfqq
->cfqg
)
2767 * It only makes sense to merge sync queues.
2769 if (!cfq_cfqq_sync(cfqq
))
2771 if (CFQQ_SEEKY(cfqq
))
2775 * Do not merge queues of different priority classes
2777 if (cfq_class_rt(cfqq
) != cfq_class_rt(cur_cfqq
))
2784 * Determine whether we should enforce idle window for this queue.
2787 static bool cfq_should_idle(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
2789 enum wl_class_t wl_class
= cfqq_class(cfqq
);
2790 struct cfq_rb_root
*st
= cfqq
->service_tree
;
2795 if (!cfqd
->cfq_slice_idle
)
2798 /* We never do for idle class queues. */
2799 if (wl_class
== IDLE_WORKLOAD
)
2802 /* We do for queues that were marked with idle window flag. */
2803 if (cfq_cfqq_idle_window(cfqq
) &&
2804 !(blk_queue_nonrot(cfqd
->queue
) && cfqd
->hw_tag
))
2808 * Otherwise, we do only if they are the last ones
2809 * in their service tree.
2811 if (st
->count
== 1 && cfq_cfqq_sync(cfqq
) &&
2812 !cfq_io_thinktime_big(cfqd
, &st
->ttime
, false))
2814 cfq_log_cfqq(cfqd
, cfqq
, "Not idling. st->count:%d", st
->count
);
2818 static void cfq_arm_slice_timer(struct cfq_data
*cfqd
)
2820 struct cfq_queue
*cfqq
= cfqd
->active_queue
;
2821 struct cfq_io_cq
*cic
;
2822 unsigned long sl
, group_idle
= 0;
2825 * SSD device without seek penalty, disable idling. But only do so
2826 * for devices that support queuing, otherwise we still have a problem
2827 * with sync vs async workloads.
2829 if (blk_queue_nonrot(cfqd
->queue
) && cfqd
->hw_tag
)
2832 WARN_ON(!RB_EMPTY_ROOT(&cfqq
->sort_list
));
2833 WARN_ON(cfq_cfqq_slice_new(cfqq
));
2836 * idle is disabled, either manually or by past process history
2838 if (!cfq_should_idle(cfqd
, cfqq
)) {
2839 /* no queue idling. Check for group idling */
2840 if (cfqd
->cfq_group_idle
)
2841 group_idle
= cfqd
->cfq_group_idle
;
2847 * still active requests from this queue, don't idle
2849 if (cfqq
->dispatched
)
2853 * task has exited, don't wait
2855 cic
= cfqd
->active_cic
;
2856 if (!cic
|| !atomic_read(&cic
->icq
.ioc
->active_ref
))
2860 * If our average think time is larger than the remaining time
2861 * slice, then don't idle. This avoids overrunning the allotted
2864 if (sample_valid(cic
->ttime
.ttime_samples
) &&
2865 (cfqq
->slice_end
- jiffies
< cic
->ttime
.ttime_mean
)) {
2866 cfq_log_cfqq(cfqd
, cfqq
, "Not idling. think_time:%lu",
2867 cic
->ttime
.ttime_mean
);
2871 /* There are other queues in the group, don't do group idle */
2872 if (group_idle
&& cfqq
->cfqg
->nr_cfqq
> 1)
2875 cfq_mark_cfqq_wait_request(cfqq
);
2878 sl
= cfqd
->cfq_group_idle
;
2880 sl
= cfqd
->cfq_slice_idle
;
2882 mod_timer(&cfqd
->idle_slice_timer
, jiffies
+ sl
);
2883 cfqg_stats_set_start_idle_time(cfqq
->cfqg
);
2884 cfq_log_cfqq(cfqd
, cfqq
, "arm_idle: %lu group_idle: %d", sl
,
2885 group_idle
? 1 : 0);
2889 * Move request from internal lists to the request queue dispatch list.
2891 static void cfq_dispatch_insert(struct request_queue
*q
, struct request
*rq
)
2893 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
2894 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
2896 cfq_log_cfqq(cfqd
, cfqq
, "dispatch_insert");
2898 cfqq
->next_rq
= cfq_find_next_rq(cfqd
, cfqq
, rq
);
2899 cfq_remove_request(rq
);
2901 (RQ_CFQG(rq
))->dispatched
++;
2902 elv_dispatch_sort(q
, rq
);
2904 cfqd
->rq_in_flight
[cfq_cfqq_sync(cfqq
)]++;
2905 cfqq
->nr_sectors
+= blk_rq_sectors(rq
);
2909 * return expired entry, or NULL to just start from scratch in rbtree
2911 static struct request
*cfq_check_fifo(struct cfq_queue
*cfqq
)
2913 struct request
*rq
= NULL
;
2915 if (cfq_cfqq_fifo_expire(cfqq
))
2918 cfq_mark_cfqq_fifo_expire(cfqq
);
2920 if (list_empty(&cfqq
->fifo
))
2923 rq
= rq_entry_fifo(cfqq
->fifo
.next
);
2924 if (time_before(jiffies
, rq
->fifo_time
))
2927 cfq_log_cfqq(cfqq
->cfqd
, cfqq
, "fifo=%p", rq
);
2932 cfq_prio_to_maxrq(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
2934 const int base_rq
= cfqd
->cfq_slice_async_rq
;
2936 WARN_ON(cfqq
->ioprio
>= IOPRIO_BE_NR
);
2938 return 2 * base_rq
* (IOPRIO_BE_NR
- cfqq
->ioprio
);
2942 * Must be called with the queue_lock held.
2944 static int cfqq_process_refs(struct cfq_queue
*cfqq
)
2946 int process_refs
, io_refs
;
2948 io_refs
= cfqq
->allocated
[READ
] + cfqq
->allocated
[WRITE
];
2949 process_refs
= cfqq
->ref
- io_refs
;
2950 BUG_ON(process_refs
< 0);
2951 return process_refs
;
2954 static void cfq_setup_merge(struct cfq_queue
*cfqq
, struct cfq_queue
*new_cfqq
)
2956 int process_refs
, new_process_refs
;
2957 struct cfq_queue
*__cfqq
;
2960 * If there are no process references on the new_cfqq, then it is
2961 * unsafe to follow the ->new_cfqq chain as other cfqq's in the
2962 * chain may have dropped their last reference (not just their
2963 * last process reference).
2965 if (!cfqq_process_refs(new_cfqq
))
2968 /* Avoid a circular list and skip interim queue merges */
2969 while ((__cfqq
= new_cfqq
->new_cfqq
)) {
2975 process_refs
= cfqq_process_refs(cfqq
);
2976 new_process_refs
= cfqq_process_refs(new_cfqq
);
2978 * If the process for the cfqq has gone away, there is no
2979 * sense in merging the queues.
2981 if (process_refs
== 0 || new_process_refs
== 0)
2985 * Merge in the direction of the lesser amount of work.
2987 if (new_process_refs
>= process_refs
) {
2988 cfqq
->new_cfqq
= new_cfqq
;
2989 new_cfqq
->ref
+= process_refs
;
2991 new_cfqq
->new_cfqq
= cfqq
;
2992 cfqq
->ref
+= new_process_refs
;
2996 static enum wl_type_t
cfq_choose_wl_type(struct cfq_data
*cfqd
,
2997 struct cfq_group
*cfqg
, enum wl_class_t wl_class
)
2999 struct cfq_queue
*queue
;
3001 bool key_valid
= false;
3002 unsigned long lowest_key
= 0;
3003 enum wl_type_t cur_best
= SYNC_NOIDLE_WORKLOAD
;
3005 for (i
= 0; i
<= SYNC_WORKLOAD
; ++i
) {
3006 /* select the one with lowest rb_key */
3007 queue
= cfq_rb_first(st_for(cfqg
, wl_class
, i
));
3009 (!key_valid
|| time_before(queue
->rb_key
, lowest_key
))) {
3010 lowest_key
= queue
->rb_key
;
3020 choose_wl_class_and_type(struct cfq_data
*cfqd
, struct cfq_group
*cfqg
)
3024 struct cfq_rb_root
*st
;
3025 unsigned group_slice
;
3026 enum wl_class_t original_class
= cfqd
->serving_wl_class
;
3028 /* Choose next priority. RT > BE > IDLE */
3029 if (cfq_group_busy_queues_wl(RT_WORKLOAD
, cfqd
, cfqg
))
3030 cfqd
->serving_wl_class
= RT_WORKLOAD
;
3031 else if (cfq_group_busy_queues_wl(BE_WORKLOAD
, cfqd
, cfqg
))
3032 cfqd
->serving_wl_class
= BE_WORKLOAD
;
3034 cfqd
->serving_wl_class
= IDLE_WORKLOAD
;
3035 cfqd
->workload_expires
= jiffies
+ 1;
3039 if (original_class
!= cfqd
->serving_wl_class
)
3043 * For RT and BE, we have to choose also the type
3044 * (SYNC, SYNC_NOIDLE, ASYNC), and to compute a workload
3047 st
= st_for(cfqg
, cfqd
->serving_wl_class
, cfqd
->serving_wl_type
);
3051 * check workload expiration, and that we still have other queues ready
3053 if (count
&& !time_after(jiffies
, cfqd
->workload_expires
))
3057 /* otherwise select new workload type */
3058 cfqd
->serving_wl_type
= cfq_choose_wl_type(cfqd
, cfqg
,
3059 cfqd
->serving_wl_class
);
3060 st
= st_for(cfqg
, cfqd
->serving_wl_class
, cfqd
->serving_wl_type
);
3064 * the workload slice is computed as a fraction of target latency
3065 * proportional to the number of queues in that workload, over
3066 * all the queues in the same priority class
3068 group_slice
= cfq_group_slice(cfqd
, cfqg
);
3070 slice
= group_slice
* count
/
3071 max_t(unsigned, cfqg
->busy_queues_avg
[cfqd
->serving_wl_class
],
3072 cfq_group_busy_queues_wl(cfqd
->serving_wl_class
, cfqd
,
3075 if (cfqd
->serving_wl_type
== ASYNC_WORKLOAD
) {
3079 * Async queues are currently system wide. Just taking
3080 * proportion of queues with-in same group will lead to higher
3081 * async ratio system wide as generally root group is going
3082 * to have higher weight. A more accurate thing would be to
3083 * calculate system wide asnc/sync ratio.
3085 tmp
= cfqd
->cfq_target_latency
*
3086 cfqg_busy_async_queues(cfqd
, cfqg
);
3087 tmp
= tmp
/cfqd
->busy_queues
;
3088 slice
= min_t(unsigned, slice
, tmp
);
3090 /* async workload slice is scaled down according to
3091 * the sync/async slice ratio. */
3092 slice
= slice
* cfqd
->cfq_slice
[0] / cfqd
->cfq_slice
[1];
3094 /* sync workload slice is at least 2 * cfq_slice_idle */
3095 slice
= max(slice
, 2 * cfqd
->cfq_slice_idle
);
3097 slice
= max_t(unsigned, slice
, CFQ_MIN_TT
);
3098 cfq_log(cfqd
, "workload slice:%d", slice
);
3099 cfqd
->workload_expires
= jiffies
+ slice
;
3102 static struct cfq_group
*cfq_get_next_cfqg(struct cfq_data
*cfqd
)
3104 struct cfq_rb_root
*st
= &cfqd
->grp_service_tree
;
3105 struct cfq_group
*cfqg
;
3107 if (RB_EMPTY_ROOT(&st
->rb
))
3109 cfqg
= cfq_rb_first_group(st
);
3110 update_min_vdisktime(st
);
3114 static void cfq_choose_cfqg(struct cfq_data
*cfqd
)
3116 struct cfq_group
*cfqg
= cfq_get_next_cfqg(cfqd
);
3118 cfqd
->serving_group
= cfqg
;
3120 /* Restore the workload type data */
3121 if (cfqg
->saved_wl_slice
) {
3122 cfqd
->workload_expires
= jiffies
+ cfqg
->saved_wl_slice
;
3123 cfqd
->serving_wl_type
= cfqg
->saved_wl_type
;
3124 cfqd
->serving_wl_class
= cfqg
->saved_wl_class
;
3126 cfqd
->workload_expires
= jiffies
- 1;
3128 choose_wl_class_and_type(cfqd
, cfqg
);
3132 * Select a queue for service. If we have a current active queue,
3133 * check whether to continue servicing it, or retrieve and set a new one.
3135 static struct cfq_queue
*cfq_select_queue(struct cfq_data
*cfqd
)
3137 struct cfq_queue
*cfqq
, *new_cfqq
= NULL
;
3139 cfqq
= cfqd
->active_queue
;
3143 if (!cfqd
->rq_queued
)
3147 * We were waiting for group to get backlogged. Expire the queue
3149 if (cfq_cfqq_wait_busy(cfqq
) && !RB_EMPTY_ROOT(&cfqq
->sort_list
))
3153 * The active queue has run out of time, expire it and select new.
3155 if (cfq_slice_used(cfqq
) && !cfq_cfqq_must_dispatch(cfqq
)) {
3157 * If slice had not expired at the completion of last request
3158 * we might not have turned on wait_busy flag. Don't expire
3159 * the queue yet. Allow the group to get backlogged.
3161 * The very fact that we have used the slice, that means we
3162 * have been idling all along on this queue and it should be
3163 * ok to wait for this request to complete.
3165 if (cfqq
->cfqg
->nr_cfqq
== 1 && RB_EMPTY_ROOT(&cfqq
->sort_list
)
3166 && cfqq
->dispatched
&& cfq_should_idle(cfqd
, cfqq
)) {
3170 goto check_group_idle
;
3174 * The active queue has requests and isn't expired, allow it to
3177 if (!RB_EMPTY_ROOT(&cfqq
->sort_list
))
3181 * If another queue has a request waiting within our mean seek
3182 * distance, let it run. The expire code will check for close
3183 * cooperators and put the close queue at the front of the service
3184 * tree. If possible, merge the expiring queue with the new cfqq.
3186 new_cfqq
= cfq_close_cooperator(cfqd
, cfqq
);
3188 if (!cfqq
->new_cfqq
)
3189 cfq_setup_merge(cfqq
, new_cfqq
);
3194 * No requests pending. If the active queue still has requests in
3195 * flight or is idling for a new request, allow either of these
3196 * conditions to happen (or time out) before selecting a new queue.
3198 if (timer_pending(&cfqd
->idle_slice_timer
)) {
3204 * This is a deep seek queue, but the device is much faster than
3205 * the queue can deliver, don't idle
3207 if (CFQQ_SEEKY(cfqq
) && cfq_cfqq_idle_window(cfqq
) &&
3208 (cfq_cfqq_slice_new(cfqq
) ||
3209 (cfqq
->slice_end
- jiffies
> jiffies
- cfqq
->slice_start
))) {
3210 cfq_clear_cfqq_deep(cfqq
);
3211 cfq_clear_cfqq_idle_window(cfqq
);
3214 if (cfqq
->dispatched
&& cfq_should_idle(cfqd
, cfqq
)) {
3220 * If group idle is enabled and there are requests dispatched from
3221 * this group, wait for requests to complete.
3224 if (cfqd
->cfq_group_idle
&& cfqq
->cfqg
->nr_cfqq
== 1 &&
3225 cfqq
->cfqg
->dispatched
&&
3226 !cfq_io_thinktime_big(cfqd
, &cfqq
->cfqg
->ttime
, true)) {
3232 cfq_slice_expired(cfqd
, 0);
3235 * Current queue expired. Check if we have to switch to a new
3239 cfq_choose_cfqg(cfqd
);
3241 cfqq
= cfq_set_active_queue(cfqd
, new_cfqq
);
3246 static int __cfq_forced_dispatch_cfqq(struct cfq_queue
*cfqq
)
3250 while (cfqq
->next_rq
) {
3251 cfq_dispatch_insert(cfqq
->cfqd
->queue
, cfqq
->next_rq
);
3255 BUG_ON(!list_empty(&cfqq
->fifo
));
3257 /* By default cfqq is not expired if it is empty. Do it explicitly */
3258 __cfq_slice_expired(cfqq
->cfqd
, cfqq
, 0);
3263 * Drain our current requests. Used for barriers and when switching
3264 * io schedulers on-the-fly.
3266 static int cfq_forced_dispatch(struct cfq_data
*cfqd
)
3268 struct cfq_queue
*cfqq
;
3271 /* Expire the timeslice of the current active queue first */
3272 cfq_slice_expired(cfqd
, 0);
3273 while ((cfqq
= cfq_get_next_queue_forced(cfqd
)) != NULL
) {
3274 __cfq_set_active_queue(cfqd
, cfqq
);
3275 dispatched
+= __cfq_forced_dispatch_cfqq(cfqq
);
3278 BUG_ON(cfqd
->busy_queues
);
3280 cfq_log(cfqd
, "forced_dispatch=%d", dispatched
);
3284 static inline bool cfq_slice_used_soon(struct cfq_data
*cfqd
,
3285 struct cfq_queue
*cfqq
)
3287 /* the queue hasn't finished any request, can't estimate */
3288 if (cfq_cfqq_slice_new(cfqq
))
3290 if (time_after(jiffies
+ cfqd
->cfq_slice_idle
* cfqq
->dispatched
,
3297 static bool cfq_may_dispatch(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
3299 unsigned int max_dispatch
;
3302 * Drain async requests before we start sync IO
3304 if (cfq_should_idle(cfqd
, cfqq
) && cfqd
->rq_in_flight
[BLK_RW_ASYNC
])
3308 * If this is an async queue and we have sync IO in flight, let it wait
3310 if (cfqd
->rq_in_flight
[BLK_RW_SYNC
] && !cfq_cfqq_sync(cfqq
))
3313 max_dispatch
= max_t(unsigned int, cfqd
->cfq_quantum
/ 2, 1);
3314 if (cfq_class_idle(cfqq
))
3318 * Does this cfqq already have too much IO in flight?
3320 if (cfqq
->dispatched
>= max_dispatch
) {
3321 bool promote_sync
= false;
3323 * idle queue must always only have a single IO in flight
3325 if (cfq_class_idle(cfqq
))
3329 * If there is only one sync queue
3330 * we can ignore async queue here and give the sync
3331 * queue no dispatch limit. The reason is a sync queue can
3332 * preempt async queue, limiting the sync queue doesn't make
3333 * sense. This is useful for aiostress test.
3335 if (cfq_cfqq_sync(cfqq
) && cfqd
->busy_sync_queues
== 1)
3336 promote_sync
= true;
3339 * We have other queues, don't allow more IO from this one
3341 if (cfqd
->busy_queues
> 1 && cfq_slice_used_soon(cfqd
, cfqq
) &&
3346 * Sole queue user, no limit
3348 if (cfqd
->busy_queues
== 1 || promote_sync
)
3352 * Normally we start throttling cfqq when cfq_quantum/2
3353 * requests have been dispatched. But we can drive
3354 * deeper queue depths at the beginning of slice
3355 * subjected to upper limit of cfq_quantum.
3357 max_dispatch
= cfqd
->cfq_quantum
;
3361 * Async queues must wait a bit before being allowed dispatch.
3362 * We also ramp up the dispatch depth gradually for async IO,
3363 * based on the last sync IO we serviced
3365 if (!cfq_cfqq_sync(cfqq
) && cfqd
->cfq_latency
) {
3366 unsigned long last_sync
= jiffies
- cfqd
->last_delayed_sync
;
3369 depth
= last_sync
/ cfqd
->cfq_slice
[1];
3370 if (!depth
&& !cfqq
->dispatched
)
3372 if (depth
< max_dispatch
)
3373 max_dispatch
= depth
;
3377 * If we're below the current max, allow a dispatch
3379 return cfqq
->dispatched
< max_dispatch
;
3383 * Dispatch a request from cfqq, moving them to the request queue
3386 static bool cfq_dispatch_request(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
3390 BUG_ON(RB_EMPTY_ROOT(&cfqq
->sort_list
));
3392 if (!cfq_may_dispatch(cfqd
, cfqq
))
3396 * follow expired path, else get first next available
3398 rq
= cfq_check_fifo(cfqq
);
3403 * insert request into driver dispatch list
3405 cfq_dispatch_insert(cfqd
->queue
, rq
);
3407 if (!cfqd
->active_cic
) {
3408 struct cfq_io_cq
*cic
= RQ_CIC(rq
);
3410 atomic_long_inc(&cic
->icq
.ioc
->refcount
);
3411 cfqd
->active_cic
= cic
;
3418 * Find the cfqq that we need to service and move a request from that to the
3421 static int cfq_dispatch_requests(struct request_queue
*q
, int force
)
3423 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
3424 struct cfq_queue
*cfqq
;
3426 if (!cfqd
->busy_queues
)
3429 if (unlikely(force
))
3430 return cfq_forced_dispatch(cfqd
);
3432 cfqq
= cfq_select_queue(cfqd
);
3437 * Dispatch a request from this cfqq, if it is allowed
3439 if (!cfq_dispatch_request(cfqd
, cfqq
))
3442 cfqq
->slice_dispatch
++;
3443 cfq_clear_cfqq_must_dispatch(cfqq
);
3446 * expire an async queue immediately if it has used up its slice. idle
3447 * queue always expire after 1 dispatch round.
3449 if (cfqd
->busy_queues
> 1 && ((!cfq_cfqq_sync(cfqq
) &&
3450 cfqq
->slice_dispatch
>= cfq_prio_to_maxrq(cfqd
, cfqq
)) ||
3451 cfq_class_idle(cfqq
))) {
3452 cfqq
->slice_end
= jiffies
+ 1;
3453 cfq_slice_expired(cfqd
, 0);
3456 cfq_log_cfqq(cfqd
, cfqq
, "dispatched a request");
3461 * task holds one reference to the queue, dropped when task exits. each rq
3462 * in-flight on this queue also holds a reference, dropped when rq is freed.
3464 * Each cfq queue took a reference on the parent group. Drop it now.
3465 * queue lock must be held here.
3467 static void cfq_put_queue(struct cfq_queue
*cfqq
)
3469 struct cfq_data
*cfqd
= cfqq
->cfqd
;
3470 struct cfq_group
*cfqg
;
3472 BUG_ON(cfqq
->ref
<= 0);
3478 cfq_log_cfqq(cfqd
, cfqq
, "put_queue");
3479 BUG_ON(rb_first(&cfqq
->sort_list
));
3480 BUG_ON(cfqq
->allocated
[READ
] + cfqq
->allocated
[WRITE
]);
3483 if (unlikely(cfqd
->active_queue
== cfqq
)) {
3484 __cfq_slice_expired(cfqd
, cfqq
, 0);
3485 cfq_schedule_dispatch(cfqd
);
3488 BUG_ON(cfq_cfqq_on_rr(cfqq
));
3489 kmem_cache_free(cfq_pool
, cfqq
);
3493 static void cfq_put_cooperator(struct cfq_queue
*cfqq
)
3495 struct cfq_queue
*__cfqq
, *next
;
3498 * If this queue was scheduled to merge with another queue, be
3499 * sure to drop the reference taken on that queue (and others in
3500 * the merge chain). See cfq_setup_merge and cfq_merge_cfqqs.
3502 __cfqq
= cfqq
->new_cfqq
;
3504 if (__cfqq
== cfqq
) {
3505 WARN(1, "cfqq->new_cfqq loop detected\n");
3508 next
= __cfqq
->new_cfqq
;
3509 cfq_put_queue(__cfqq
);
3514 static void cfq_exit_cfqq(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
3516 if (unlikely(cfqq
== cfqd
->active_queue
)) {
3517 __cfq_slice_expired(cfqd
, cfqq
, 0);
3518 cfq_schedule_dispatch(cfqd
);
3521 cfq_put_cooperator(cfqq
);
3523 cfq_put_queue(cfqq
);
3526 static void cfq_init_icq(struct io_cq
*icq
)
3528 struct cfq_io_cq
*cic
= icq_to_cic(icq
);
3530 cic
->ttime
.last_end_request
= jiffies
;
3533 static void cfq_exit_icq(struct io_cq
*icq
)
3535 struct cfq_io_cq
*cic
= icq_to_cic(icq
);
3536 struct cfq_data
*cfqd
= cic_to_cfqd(cic
);
3538 if (cic_to_cfqq(cic
, false)) {
3539 cfq_exit_cfqq(cfqd
, cic_to_cfqq(cic
, false));
3540 cic_set_cfqq(cic
, NULL
, false);
3543 if (cic_to_cfqq(cic
, true)) {
3544 cfq_exit_cfqq(cfqd
, cic_to_cfqq(cic
, true));
3545 cic_set_cfqq(cic
, NULL
, true);
3549 static void cfq_init_prio_data(struct cfq_queue
*cfqq
, struct cfq_io_cq
*cic
)
3551 struct task_struct
*tsk
= current
;
3554 if (!cfq_cfqq_prio_changed(cfqq
))
3557 ioprio_class
= IOPRIO_PRIO_CLASS(cic
->ioprio
);
3558 switch (ioprio_class
) {
3560 printk(KERN_ERR
"cfq: bad prio %x\n", ioprio_class
);
3561 case IOPRIO_CLASS_NONE
:
3563 * no prio set, inherit CPU scheduling settings
3565 cfqq
->ioprio
= task_nice_ioprio(tsk
);
3566 cfqq
->ioprio_class
= task_nice_ioclass(tsk
);
3568 case IOPRIO_CLASS_RT
:
3569 cfqq
->ioprio
= IOPRIO_PRIO_DATA(cic
->ioprio
);
3570 cfqq
->ioprio_class
= IOPRIO_CLASS_RT
;
3572 case IOPRIO_CLASS_BE
:
3573 cfqq
->ioprio
= IOPRIO_PRIO_DATA(cic
->ioprio
);
3574 cfqq
->ioprio_class
= IOPRIO_CLASS_BE
;
3576 case IOPRIO_CLASS_IDLE
:
3577 cfqq
->ioprio_class
= IOPRIO_CLASS_IDLE
;
3579 cfq_clear_cfqq_idle_window(cfqq
);
3584 * keep track of original prio settings in case we have to temporarily
3585 * elevate the priority of this queue
3587 cfqq
->org_ioprio
= cfqq
->ioprio
;
3588 cfq_clear_cfqq_prio_changed(cfqq
);
3591 static void check_ioprio_changed(struct cfq_io_cq
*cic
, struct bio
*bio
)
3593 int ioprio
= cic
->icq
.ioc
->ioprio
;
3594 struct cfq_data
*cfqd
= cic_to_cfqd(cic
);
3595 struct cfq_queue
*cfqq
;
3598 * Check whether ioprio has changed. The condition may trigger
3599 * spuriously on a newly created cic but there's no harm.
3601 if (unlikely(!cfqd
) || likely(cic
->ioprio
== ioprio
))
3604 cfqq
= cic_to_cfqq(cic
, false);
3606 cfq_put_queue(cfqq
);
3607 cfqq
= cfq_get_queue(cfqd
, BLK_RW_ASYNC
, cic
, bio
);
3608 cic_set_cfqq(cic
, cfqq
, false);
3611 cfqq
= cic_to_cfqq(cic
, true);
3613 cfq_mark_cfqq_prio_changed(cfqq
);
3615 cic
->ioprio
= ioprio
;
3618 static void cfq_init_cfqq(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
3619 pid_t pid
, bool is_sync
)
3621 RB_CLEAR_NODE(&cfqq
->rb_node
);
3622 RB_CLEAR_NODE(&cfqq
->p_node
);
3623 INIT_LIST_HEAD(&cfqq
->fifo
);
3628 cfq_mark_cfqq_prio_changed(cfqq
);
3631 if (!cfq_class_idle(cfqq
))
3632 cfq_mark_cfqq_idle_window(cfqq
);
3633 cfq_mark_cfqq_sync(cfqq
);
3638 #ifdef CONFIG_CFQ_GROUP_IOSCHED
3639 static void check_blkcg_changed(struct cfq_io_cq
*cic
, struct bio
*bio
)
3641 struct cfq_data
*cfqd
= cic_to_cfqd(cic
);
3642 struct cfq_queue
*cfqq
;
3646 serial_nr
= bio_blkcg(bio
)->css
.serial_nr
;
3650 * Check whether blkcg has changed. The condition may trigger
3651 * spuriously on a newly created cic but there's no harm.
3653 if (unlikely(!cfqd
) || likely(cic
->blkcg_serial_nr
== serial_nr
))
3657 * Drop reference to queues. New queues will be assigned in new
3658 * group upon arrival of fresh requests.
3660 cfqq
= cic_to_cfqq(cic
, false);
3662 cfq_log_cfqq(cfqd
, cfqq
, "changed cgroup");
3663 cic_set_cfqq(cic
, NULL
, false);
3664 cfq_put_queue(cfqq
);
3667 cfqq
= cic_to_cfqq(cic
, true);
3669 cfq_log_cfqq(cfqd
, cfqq
, "changed cgroup");
3670 cic_set_cfqq(cic
, NULL
, true);
3671 cfq_put_queue(cfqq
);
3674 cic
->blkcg_serial_nr
= serial_nr
;
3677 static inline void check_blkcg_changed(struct cfq_io_cq
*cic
, struct bio
*bio
) { }
3678 #endif /* CONFIG_CFQ_GROUP_IOSCHED */
3680 static struct cfq_queue
**
3681 cfq_async_queue_prio(struct cfq_group
*cfqg
, int ioprio_class
, int ioprio
)
3683 switch (ioprio_class
) {
3684 case IOPRIO_CLASS_RT
:
3685 return &cfqg
->async_cfqq
[0][ioprio
];
3686 case IOPRIO_CLASS_NONE
:
3687 ioprio
= IOPRIO_NORM
;
3689 case IOPRIO_CLASS_BE
:
3690 return &cfqg
->async_cfqq
[1][ioprio
];
3691 case IOPRIO_CLASS_IDLE
:
3692 return &cfqg
->async_idle_cfqq
;
3698 static struct cfq_queue
*
3699 cfq_get_queue(struct cfq_data
*cfqd
, bool is_sync
, struct cfq_io_cq
*cic
,
3702 int ioprio_class
= IOPRIO_PRIO_CLASS(cic
->ioprio
);
3703 int ioprio
= IOPRIO_PRIO_DATA(cic
->ioprio
);
3704 struct cfq_queue
**async_cfqq
= NULL
;
3705 struct cfq_queue
*cfqq
;
3706 struct cfq_group
*cfqg
;
3709 cfqg
= cfq_lookup_cfqg(cfqd
, bio_blkcg(bio
));
3711 cfqq
= &cfqd
->oom_cfqq
;
3716 if (!ioprio_valid(cic
->ioprio
)) {
3717 struct task_struct
*tsk
= current
;
3718 ioprio
= task_nice_ioprio(tsk
);
3719 ioprio_class
= task_nice_ioclass(tsk
);
3721 async_cfqq
= cfq_async_queue_prio(cfqg
, ioprio_class
, ioprio
);
3727 cfqq
= kmem_cache_alloc_node(cfq_pool
, GFP_NOWAIT
| __GFP_ZERO
,
3730 cfqq
= &cfqd
->oom_cfqq
;
3734 cfq_init_cfqq(cfqd
, cfqq
, current
->pid
, is_sync
);
3735 cfq_init_prio_data(cfqq
, cic
);
3736 cfq_link_cfqq_cfqg(cfqq
, cfqg
);
3737 cfq_log_cfqq(cfqd
, cfqq
, "alloced");
3740 /* a new async queue is created, pin and remember */
3751 __cfq_update_io_thinktime(struct cfq_ttime
*ttime
, unsigned long slice_idle
)
3753 unsigned long elapsed
= jiffies
- ttime
->last_end_request
;
3754 elapsed
= min(elapsed
, 2UL * slice_idle
);
3756 ttime
->ttime_samples
= (7*ttime
->ttime_samples
+ 256) / 8;
3757 ttime
->ttime_total
= (7*ttime
->ttime_total
+ 256*elapsed
) / 8;
3758 ttime
->ttime_mean
= (ttime
->ttime_total
+ 128) / ttime
->ttime_samples
;
3762 cfq_update_io_thinktime(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
3763 struct cfq_io_cq
*cic
)
3765 if (cfq_cfqq_sync(cfqq
)) {
3766 __cfq_update_io_thinktime(&cic
->ttime
, cfqd
->cfq_slice_idle
);
3767 __cfq_update_io_thinktime(&cfqq
->service_tree
->ttime
,
3768 cfqd
->cfq_slice_idle
);
3770 #ifdef CONFIG_CFQ_GROUP_IOSCHED
3771 __cfq_update_io_thinktime(&cfqq
->cfqg
->ttime
, cfqd
->cfq_group_idle
);
3776 cfq_update_io_seektime(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
3780 sector_t n_sec
= blk_rq_sectors(rq
);
3781 if (cfqq
->last_request_pos
) {
3782 if (cfqq
->last_request_pos
< blk_rq_pos(rq
))
3783 sdist
= blk_rq_pos(rq
) - cfqq
->last_request_pos
;
3785 sdist
= cfqq
->last_request_pos
- blk_rq_pos(rq
);
3788 cfqq
->seek_history
<<= 1;
3789 if (blk_queue_nonrot(cfqd
->queue
))
3790 cfqq
->seek_history
|= (n_sec
< CFQQ_SECT_THR_NONROT
);
3792 cfqq
->seek_history
|= (sdist
> CFQQ_SEEK_THR
);
3796 * Disable idle window if the process thinks too long or seeks so much that
3800 cfq_update_idle_window(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
3801 struct cfq_io_cq
*cic
)
3803 int old_idle
, enable_idle
;
3806 * Don't idle for async or idle io prio class
3808 if (!cfq_cfqq_sync(cfqq
) || cfq_class_idle(cfqq
))
3811 enable_idle
= old_idle
= cfq_cfqq_idle_window(cfqq
);
3813 if (cfqq
->queued
[0] + cfqq
->queued
[1] >= 4)
3814 cfq_mark_cfqq_deep(cfqq
);
3816 if (cfqq
->next_rq
&& (cfqq
->next_rq
->cmd_flags
& REQ_NOIDLE
))
3818 else if (!atomic_read(&cic
->icq
.ioc
->active_ref
) ||
3819 !cfqd
->cfq_slice_idle
||
3820 (!cfq_cfqq_deep(cfqq
) && CFQQ_SEEKY(cfqq
)))
3822 else if (sample_valid(cic
->ttime
.ttime_samples
)) {
3823 if (cic
->ttime
.ttime_mean
> cfqd
->cfq_slice_idle
)
3829 if (old_idle
!= enable_idle
) {
3830 cfq_log_cfqq(cfqd
, cfqq
, "idle=%d", enable_idle
);
3832 cfq_mark_cfqq_idle_window(cfqq
);
3834 cfq_clear_cfqq_idle_window(cfqq
);
3839 * Check if new_cfqq should preempt the currently active queue. Return 0 for
3840 * no or if we aren't sure, a 1 will cause a preempt.
3843 cfq_should_preempt(struct cfq_data
*cfqd
, struct cfq_queue
*new_cfqq
,
3846 struct cfq_queue
*cfqq
;
3848 cfqq
= cfqd
->active_queue
;
3852 if (cfq_class_idle(new_cfqq
))
3855 if (cfq_class_idle(cfqq
))
3859 * Don't allow a non-RT request to preempt an ongoing RT cfqq timeslice.
3861 if (cfq_class_rt(cfqq
) && !cfq_class_rt(new_cfqq
))
3865 * if the new request is sync, but the currently running queue is
3866 * not, let the sync request have priority.
3868 if (rq_is_sync(rq
) && !cfq_cfqq_sync(cfqq
))
3871 if (new_cfqq
->cfqg
!= cfqq
->cfqg
)
3874 if (cfq_slice_used(cfqq
))
3877 /* Allow preemption only if we are idling on sync-noidle tree */
3878 if (cfqd
->serving_wl_type
== SYNC_NOIDLE_WORKLOAD
&&
3879 cfqq_type(new_cfqq
) == SYNC_NOIDLE_WORKLOAD
&&
3880 new_cfqq
->service_tree
->count
== 2 &&
3881 RB_EMPTY_ROOT(&cfqq
->sort_list
))
3885 * So both queues are sync. Let the new request get disk time if
3886 * it's a metadata request and the current queue is doing regular IO.
3888 if ((rq
->cmd_flags
& REQ_PRIO
) && !cfqq
->prio_pending
)
3892 * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice.
3894 if (cfq_class_rt(new_cfqq
) && !cfq_class_rt(cfqq
))
3897 /* An idle queue should not be idle now for some reason */
3898 if (RB_EMPTY_ROOT(&cfqq
->sort_list
) && !cfq_should_idle(cfqd
, cfqq
))
3901 if (!cfqd
->active_cic
|| !cfq_cfqq_wait_request(cfqq
))
3905 * if this request is as-good as one we would expect from the
3906 * current cfqq, let it preempt
3908 if (cfq_rq_close(cfqd
, cfqq
, rq
))
3915 * cfqq preempts the active queue. if we allowed preempt with no slice left,
3916 * let it have half of its nominal slice.
3918 static void cfq_preempt_queue(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
3920 enum wl_type_t old_type
= cfqq_type(cfqd
->active_queue
);
3922 cfq_log_cfqq(cfqd
, cfqq
, "preempt");
3923 cfq_slice_expired(cfqd
, 1);
3926 * workload type is changed, don't save slice, otherwise preempt
3929 if (old_type
!= cfqq_type(cfqq
))
3930 cfqq
->cfqg
->saved_wl_slice
= 0;
3933 * Put the new queue at the front of the of the current list,
3934 * so we know that it will be selected next.
3936 BUG_ON(!cfq_cfqq_on_rr(cfqq
));
3938 cfq_service_tree_add(cfqd
, cfqq
, 1);
3940 cfqq
->slice_end
= 0;
3941 cfq_mark_cfqq_slice_new(cfqq
);
3945 * Called when a new fs request (rq) is added (to cfqq). Check if there's
3946 * something we should do about it
3949 cfq_rq_enqueued(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
,
3952 struct cfq_io_cq
*cic
= RQ_CIC(rq
);
3955 if (rq
->cmd_flags
& REQ_PRIO
)
3956 cfqq
->prio_pending
++;
3958 cfq_update_io_thinktime(cfqd
, cfqq
, cic
);
3959 cfq_update_io_seektime(cfqd
, cfqq
, rq
);
3960 cfq_update_idle_window(cfqd
, cfqq
, cic
);
3962 cfqq
->last_request_pos
= blk_rq_pos(rq
) + blk_rq_sectors(rq
);
3964 if (cfqq
== cfqd
->active_queue
) {
3966 * Remember that we saw a request from this process, but
3967 * don't start queuing just yet. Otherwise we risk seeing lots
3968 * of tiny requests, because we disrupt the normal plugging
3969 * and merging. If the request is already larger than a single
3970 * page, let it rip immediately. For that case we assume that
3971 * merging is already done. Ditto for a busy system that
3972 * has other work pending, don't risk delaying until the
3973 * idle timer unplug to continue working.
3975 if (cfq_cfqq_wait_request(cfqq
)) {
3976 if (blk_rq_bytes(rq
) > PAGE_CACHE_SIZE
||
3977 cfqd
->busy_queues
> 1) {
3978 cfq_del_timer(cfqd
, cfqq
);
3979 cfq_clear_cfqq_wait_request(cfqq
);
3980 __blk_run_queue(cfqd
->queue
);
3982 cfqg_stats_update_idle_time(cfqq
->cfqg
);
3983 cfq_mark_cfqq_must_dispatch(cfqq
);
3986 } else if (cfq_should_preempt(cfqd
, cfqq
, rq
)) {
3988 * not the active queue - expire current slice if it is
3989 * idle and has expired it's mean thinktime or this new queue
3990 * has some old slice time left and is of higher priority or
3991 * this new queue is RT and the current one is BE
3993 cfq_preempt_queue(cfqd
, cfqq
);
3994 __blk_run_queue(cfqd
->queue
);
3998 static void cfq_insert_request(struct request_queue
*q
, struct request
*rq
)
4000 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
4001 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
4003 cfq_log_cfqq(cfqd
, cfqq
, "insert_request");
4004 cfq_init_prio_data(cfqq
, RQ_CIC(rq
));
4006 rq
->fifo_time
= jiffies
+ cfqd
->cfq_fifo_expire
[rq_is_sync(rq
)];
4007 list_add_tail(&rq
->queuelist
, &cfqq
->fifo
);
4009 cfqg_stats_update_io_add(RQ_CFQG(rq
), cfqd
->serving_group
,
4011 cfq_rq_enqueued(cfqd
, cfqq
, rq
);
4015 * Update hw_tag based on peak queue depth over 50 samples under
4018 static void cfq_update_hw_tag(struct cfq_data
*cfqd
)
4020 struct cfq_queue
*cfqq
= cfqd
->active_queue
;
4022 if (cfqd
->rq_in_driver
> cfqd
->hw_tag_est_depth
)
4023 cfqd
->hw_tag_est_depth
= cfqd
->rq_in_driver
;
4025 if (cfqd
->hw_tag
== 1)
4028 if (cfqd
->rq_queued
<= CFQ_HW_QUEUE_MIN
&&
4029 cfqd
->rq_in_driver
<= CFQ_HW_QUEUE_MIN
)
4033 * If active queue hasn't enough requests and can idle, cfq might not
4034 * dispatch sufficient requests to hardware. Don't zero hw_tag in this
4037 if (cfqq
&& cfq_cfqq_idle_window(cfqq
) &&
4038 cfqq
->dispatched
+ cfqq
->queued
[0] + cfqq
->queued
[1] <
4039 CFQ_HW_QUEUE_MIN
&& cfqd
->rq_in_driver
< CFQ_HW_QUEUE_MIN
)
4042 if (cfqd
->hw_tag_samples
++ < 50)
4045 if (cfqd
->hw_tag_est_depth
>= CFQ_HW_QUEUE_MIN
)
4051 static bool cfq_should_wait_busy(struct cfq_data
*cfqd
, struct cfq_queue
*cfqq
)
4053 struct cfq_io_cq
*cic
= cfqd
->active_cic
;
4055 /* If the queue already has requests, don't wait */
4056 if (!RB_EMPTY_ROOT(&cfqq
->sort_list
))
4059 /* If there are other queues in the group, don't wait */
4060 if (cfqq
->cfqg
->nr_cfqq
> 1)
4063 /* the only queue in the group, but think time is big */
4064 if (cfq_io_thinktime_big(cfqd
, &cfqq
->cfqg
->ttime
, true))
4067 if (cfq_slice_used(cfqq
))
4070 /* if slice left is less than think time, wait busy */
4071 if (cic
&& sample_valid(cic
->ttime
.ttime_samples
)
4072 && (cfqq
->slice_end
- jiffies
< cic
->ttime
.ttime_mean
))
4076 * If think times is less than a jiffy than ttime_mean=0 and above
4077 * will not be true. It might happen that slice has not expired yet
4078 * but will expire soon (4-5 ns) during select_queue(). To cover the
4079 * case where think time is less than a jiffy, mark the queue wait
4080 * busy if only 1 jiffy is left in the slice.
4082 if (cfqq
->slice_end
- jiffies
== 1)
4088 static void cfq_completed_request(struct request_queue
*q
, struct request
*rq
)
4090 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
4091 struct cfq_data
*cfqd
= cfqq
->cfqd
;
4092 const int sync
= rq_is_sync(rq
);
4096 cfq_log_cfqq(cfqd
, cfqq
, "complete rqnoidle %d",
4097 !!(rq
->cmd_flags
& REQ_NOIDLE
));
4099 cfq_update_hw_tag(cfqd
);
4101 WARN_ON(!cfqd
->rq_in_driver
);
4102 WARN_ON(!cfqq
->dispatched
);
4103 cfqd
->rq_in_driver
--;
4105 (RQ_CFQG(rq
))->dispatched
--;
4106 cfqg_stats_update_completion(cfqq
->cfqg
, rq_start_time_ns(rq
),
4107 rq_io_start_time_ns(rq
), rq
->cmd_flags
);
4109 cfqd
->rq_in_flight
[cfq_cfqq_sync(cfqq
)]--;
4112 struct cfq_rb_root
*st
;
4114 RQ_CIC(rq
)->ttime
.last_end_request
= now
;
4116 if (cfq_cfqq_on_rr(cfqq
))
4117 st
= cfqq
->service_tree
;
4119 st
= st_for(cfqq
->cfqg
, cfqq_class(cfqq
),
4122 st
->ttime
.last_end_request
= now
;
4123 if (!time_after(rq
->start_time
+ cfqd
->cfq_fifo_expire
[1], now
))
4124 cfqd
->last_delayed_sync
= now
;
4127 #ifdef CONFIG_CFQ_GROUP_IOSCHED
4128 cfqq
->cfqg
->ttime
.last_end_request
= now
;
4132 * If this is the active queue, check if it needs to be expired,
4133 * or if we want to idle in case it has no pending requests.
4135 if (cfqd
->active_queue
== cfqq
) {
4136 const bool cfqq_empty
= RB_EMPTY_ROOT(&cfqq
->sort_list
);
4138 if (cfq_cfqq_slice_new(cfqq
)) {
4139 cfq_set_prio_slice(cfqd
, cfqq
);
4140 cfq_clear_cfqq_slice_new(cfqq
);
4144 * Should we wait for next request to come in before we expire
4147 if (cfq_should_wait_busy(cfqd
, cfqq
)) {
4148 unsigned long extend_sl
= cfqd
->cfq_slice_idle
;
4149 if (!cfqd
->cfq_slice_idle
)
4150 extend_sl
= cfqd
->cfq_group_idle
;
4151 cfqq
->slice_end
= jiffies
+ extend_sl
;
4152 cfq_mark_cfqq_wait_busy(cfqq
);
4153 cfq_log_cfqq(cfqd
, cfqq
, "will busy wait");
4157 * Idling is not enabled on:
4159 * - idle-priority queues
4161 * - queues with still some requests queued
4162 * - when there is a close cooperator
4164 if (cfq_slice_used(cfqq
) || cfq_class_idle(cfqq
))
4165 cfq_slice_expired(cfqd
, 1);
4166 else if (sync
&& cfqq_empty
&&
4167 !cfq_close_cooperator(cfqd
, cfqq
)) {
4168 cfq_arm_slice_timer(cfqd
);
4172 if (!cfqd
->rq_in_driver
)
4173 cfq_schedule_dispatch(cfqd
);
4176 static inline int __cfq_may_queue(struct cfq_queue
*cfqq
)
4178 if (cfq_cfqq_wait_request(cfqq
) && !cfq_cfqq_must_alloc_slice(cfqq
)) {
4179 cfq_mark_cfqq_must_alloc_slice(cfqq
);
4180 return ELV_MQUEUE_MUST
;
4183 return ELV_MQUEUE_MAY
;
4186 static int cfq_may_queue(struct request_queue
*q
, int rw
)
4188 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
4189 struct task_struct
*tsk
= current
;
4190 struct cfq_io_cq
*cic
;
4191 struct cfq_queue
*cfqq
;
4194 * don't force setup of a queue from here, as a call to may_queue
4195 * does not necessarily imply that a request actually will be queued.
4196 * so just lookup a possibly existing queue, or return 'may queue'
4199 cic
= cfq_cic_lookup(cfqd
, tsk
->io_context
);
4201 return ELV_MQUEUE_MAY
;
4203 cfqq
= cic_to_cfqq(cic
, rw_is_sync(rw
));
4205 cfq_init_prio_data(cfqq
, cic
);
4207 return __cfq_may_queue(cfqq
);
4210 return ELV_MQUEUE_MAY
;
4214 * queue lock held here
4216 static void cfq_put_request(struct request
*rq
)
4218 struct cfq_queue
*cfqq
= RQ_CFQQ(rq
);
4221 const int rw
= rq_data_dir(rq
);
4223 BUG_ON(!cfqq
->allocated
[rw
]);
4224 cfqq
->allocated
[rw
]--;
4226 /* Put down rq reference on cfqg */
4227 cfqg_put(RQ_CFQG(rq
));
4228 rq
->elv
.priv
[0] = NULL
;
4229 rq
->elv
.priv
[1] = NULL
;
4231 cfq_put_queue(cfqq
);
4235 static struct cfq_queue
*
4236 cfq_merge_cfqqs(struct cfq_data
*cfqd
, struct cfq_io_cq
*cic
,
4237 struct cfq_queue
*cfqq
)
4239 cfq_log_cfqq(cfqd
, cfqq
, "merging with queue %p", cfqq
->new_cfqq
);
4240 cic_set_cfqq(cic
, cfqq
->new_cfqq
, 1);
4241 cfq_mark_cfqq_coop(cfqq
->new_cfqq
);
4242 cfq_put_queue(cfqq
);
4243 return cic_to_cfqq(cic
, 1);
4247 * Returns NULL if a new cfqq should be allocated, or the old cfqq if this
4248 * was the last process referring to said cfqq.
4250 static struct cfq_queue
*
4251 split_cfqq(struct cfq_io_cq
*cic
, struct cfq_queue
*cfqq
)
4253 if (cfqq_process_refs(cfqq
) == 1) {
4254 cfqq
->pid
= current
->pid
;
4255 cfq_clear_cfqq_coop(cfqq
);
4256 cfq_clear_cfqq_split_coop(cfqq
);
4260 cic_set_cfqq(cic
, NULL
, 1);
4262 cfq_put_cooperator(cfqq
);
4264 cfq_put_queue(cfqq
);
4268 * Allocate cfq data structures associated with this request.
4271 cfq_set_request(struct request_queue
*q
, struct request
*rq
, struct bio
*bio
,
4274 struct cfq_data
*cfqd
= q
->elevator
->elevator_data
;
4275 struct cfq_io_cq
*cic
= icq_to_cic(rq
->elv
.icq
);
4276 const int rw
= rq_data_dir(rq
);
4277 const bool is_sync
= rq_is_sync(rq
);
4278 struct cfq_queue
*cfqq
;
4280 spin_lock_irq(q
->queue_lock
);
4282 check_ioprio_changed(cic
, bio
);
4283 check_blkcg_changed(cic
, bio
);
4285 cfqq
= cic_to_cfqq(cic
, is_sync
);
4286 if (!cfqq
|| cfqq
== &cfqd
->oom_cfqq
) {
4288 cfq_put_queue(cfqq
);
4289 cfqq
= cfq_get_queue(cfqd
, is_sync
, cic
, bio
);
4290 cic_set_cfqq(cic
, cfqq
, is_sync
);
4293 * If the queue was seeky for too long, break it apart.
4295 if (cfq_cfqq_coop(cfqq
) && cfq_cfqq_split_coop(cfqq
)) {
4296 cfq_log_cfqq(cfqd
, cfqq
, "breaking apart cfqq");
4297 cfqq
= split_cfqq(cic
, cfqq
);
4303 * Check to see if this queue is scheduled to merge with
4304 * another, closely cooperating queue. The merging of
4305 * queues happens here as it must be done in process context.
4306 * The reference on new_cfqq was taken in merge_cfqqs.
4309 cfqq
= cfq_merge_cfqqs(cfqd
, cic
, cfqq
);
4312 cfqq
->allocated
[rw
]++;
4315 cfqg_get(cfqq
->cfqg
);
4316 rq
->elv
.priv
[0] = cfqq
;
4317 rq
->elv
.priv
[1] = cfqq
->cfqg
;
4318 spin_unlock_irq(q
->queue_lock
);
4322 static void cfq_kick_queue(struct work_struct
*work
)
4324 struct cfq_data
*cfqd
=
4325 container_of(work
, struct cfq_data
, unplug_work
);
4326 struct request_queue
*q
= cfqd
->queue
;
4328 spin_lock_irq(q
->queue_lock
);
4329 __blk_run_queue(cfqd
->queue
);
4330 spin_unlock_irq(q
->queue_lock
);
4334 * Timer running if the active_queue is currently idling inside its time slice
4336 static void cfq_idle_slice_timer(unsigned long data
)
4338 struct cfq_data
*cfqd
= (struct cfq_data
*) data
;
4339 struct cfq_queue
*cfqq
;
4340 unsigned long flags
;
4343 cfq_log(cfqd
, "idle timer fired");
4345 spin_lock_irqsave(cfqd
->queue
->queue_lock
, flags
);
4347 cfqq
= cfqd
->active_queue
;
4352 * We saw a request before the queue expired, let it through
4354 if (cfq_cfqq_must_dispatch(cfqq
))
4360 if (cfq_slice_used(cfqq
))
4364 * only expire and reinvoke request handler, if there are
4365 * other queues with pending requests
4367 if (!cfqd
->busy_queues
)
4371 * not expired and it has a request pending, let it dispatch
4373 if (!RB_EMPTY_ROOT(&cfqq
->sort_list
))
4377 * Queue depth flag is reset only when the idle didn't succeed
4379 cfq_clear_cfqq_deep(cfqq
);
4382 cfq_slice_expired(cfqd
, timed_out
);
4384 cfq_schedule_dispatch(cfqd
);
4386 spin_unlock_irqrestore(cfqd
->queue
->queue_lock
, flags
);
4389 static void cfq_shutdown_timer_wq(struct cfq_data
*cfqd
)
4391 del_timer_sync(&cfqd
->idle_slice_timer
);
4392 cancel_work_sync(&cfqd
->unplug_work
);
4395 static void cfq_exit_queue(struct elevator_queue
*e
)
4397 struct cfq_data
*cfqd
= e
->elevator_data
;
4398 struct request_queue
*q
= cfqd
->queue
;
4400 cfq_shutdown_timer_wq(cfqd
);
4402 spin_lock_irq(q
->queue_lock
);
4404 if (cfqd
->active_queue
)
4405 __cfq_slice_expired(cfqd
, cfqd
->active_queue
, 0);
4407 spin_unlock_irq(q
->queue_lock
);
4409 cfq_shutdown_timer_wq(cfqd
);
4411 #ifdef CONFIG_CFQ_GROUP_IOSCHED
4412 blkcg_deactivate_policy(q
, &blkcg_policy_cfq
);
4414 kfree(cfqd
->root_group
);
4419 static int cfq_init_queue(struct request_queue
*q
, struct elevator_type
*e
)
4421 struct cfq_data
*cfqd
;
4422 struct blkcg_gq
*blkg __maybe_unused
;
4424 struct elevator_queue
*eq
;
4426 eq
= elevator_alloc(q
, e
);
4430 cfqd
= kzalloc_node(sizeof(*cfqd
), GFP_KERNEL
, q
->node
);
4432 kobject_put(&eq
->kobj
);
4435 eq
->elevator_data
= cfqd
;
4438 spin_lock_irq(q
->queue_lock
);
4440 spin_unlock_irq(q
->queue_lock
);
4442 /* Init root service tree */
4443 cfqd
->grp_service_tree
= CFQ_RB_ROOT
;
4445 /* Init root group and prefer root group over other groups by default */
4446 #ifdef CONFIG_CFQ_GROUP_IOSCHED
4447 ret
= blkcg_activate_policy(q
, &blkcg_policy_cfq
);
4451 cfqd
->root_group
= blkg_to_cfqg(q
->root_blkg
);
4454 cfqd
->root_group
= kzalloc_node(sizeof(*cfqd
->root_group
),
4455 GFP_KERNEL
, cfqd
->queue
->node
);
4456 if (!cfqd
->root_group
)
4459 cfq_init_cfqg_base(cfqd
->root_group
);
4461 cfqd
->root_group
->weight
= 2 * CFQ_WEIGHT_DEFAULT
;
4462 cfqd
->root_group
->leaf_weight
= 2 * CFQ_WEIGHT_DEFAULT
;
4465 * Not strictly needed (since RB_ROOT just clears the node and we
4466 * zeroed cfqd on alloc), but better be safe in case someone decides
4467 * to add magic to the rb code
4469 for (i
= 0; i
< CFQ_PRIO_LISTS
; i
++)
4470 cfqd
->prio_trees
[i
] = RB_ROOT
;
4473 * Our fallback cfqq if cfq_get_queue() runs into OOM issues.
4474 * Grab a permanent reference to it, so that the normal code flow
4475 * will not attempt to free it. oom_cfqq is linked to root_group
4476 * but shouldn't hold a reference as it'll never be unlinked. Lose
4477 * the reference from linking right away.
4479 cfq_init_cfqq(cfqd
, &cfqd
->oom_cfqq
, 1, 0);
4480 cfqd
->oom_cfqq
.ref
++;
4482 spin_lock_irq(q
->queue_lock
);
4483 cfq_link_cfqq_cfqg(&cfqd
->oom_cfqq
, cfqd
->root_group
);
4484 cfqg_put(cfqd
->root_group
);
4485 spin_unlock_irq(q
->queue_lock
);
4487 init_timer(&cfqd
->idle_slice_timer
);
4488 cfqd
->idle_slice_timer
.function
= cfq_idle_slice_timer
;
4489 cfqd
->idle_slice_timer
.data
= (unsigned long) cfqd
;
4491 INIT_WORK(&cfqd
->unplug_work
, cfq_kick_queue
);
4493 cfqd
->cfq_quantum
= cfq_quantum
;
4494 cfqd
->cfq_fifo_expire
[0] = cfq_fifo_expire
[0];
4495 cfqd
->cfq_fifo_expire
[1] = cfq_fifo_expire
[1];
4496 cfqd
->cfq_back_max
= cfq_back_max
;
4497 cfqd
->cfq_back_penalty
= cfq_back_penalty
;
4498 cfqd
->cfq_slice
[0] = cfq_slice_async
;
4499 cfqd
->cfq_slice
[1] = cfq_slice_sync
;
4500 cfqd
->cfq_target_latency
= cfq_target_latency
;
4501 cfqd
->cfq_slice_async_rq
= cfq_slice_async_rq
;
4502 cfqd
->cfq_slice_idle
= cfq_slice_idle
;
4503 cfqd
->cfq_group_idle
= cfq_group_idle
;
4504 cfqd
->cfq_latency
= 1;
4507 * we optimistically start assuming sync ops weren't delayed in last
4508 * second, in order to have larger depth for async operations.
4510 cfqd
->last_delayed_sync
= jiffies
- HZ
;
4515 kobject_put(&eq
->kobj
);
4519 static void cfq_registered_queue(struct request_queue
*q
)
4521 struct elevator_queue
*e
= q
->elevator
;
4522 struct cfq_data
*cfqd
= e
->elevator_data
;
4525 * Default to IOPS mode with no idling for SSDs
4527 if (blk_queue_nonrot(q
))
4528 cfqd
->cfq_slice_idle
= 0;
4532 * sysfs parts below -->
4535 cfq_var_show(unsigned int var
, char *page
)
4537 return sprintf(page
, "%u\n", var
);
4541 cfq_var_store(unsigned int *var
, const char *page
, size_t count
)
4543 char *p
= (char *) page
;
4545 *var
= simple_strtoul(p
, &p
, 10);
4549 #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \
4550 static ssize_t __FUNC(struct elevator_queue *e, char *page) \
4552 struct cfq_data *cfqd = e->elevator_data; \
4553 unsigned int __data = __VAR; \
4555 __data = jiffies_to_msecs(__data); \
4556 return cfq_var_show(__data, (page)); \
4558 SHOW_FUNCTION(cfq_quantum_show
, cfqd
->cfq_quantum
, 0);
4559 SHOW_FUNCTION(cfq_fifo_expire_sync_show
, cfqd
->cfq_fifo_expire
[1], 1);
4560 SHOW_FUNCTION(cfq_fifo_expire_async_show
, cfqd
->cfq_fifo_expire
[0], 1);
4561 SHOW_FUNCTION(cfq_back_seek_max_show
, cfqd
->cfq_back_max
, 0);
4562 SHOW_FUNCTION(cfq_back_seek_penalty_show
, cfqd
->cfq_back_penalty
, 0);
4563 SHOW_FUNCTION(cfq_slice_idle_show
, cfqd
->cfq_slice_idle
, 1);
4564 SHOW_FUNCTION(cfq_group_idle_show
, cfqd
->cfq_group_idle
, 1);
4565 SHOW_FUNCTION(cfq_slice_sync_show
, cfqd
->cfq_slice
[1], 1);
4566 SHOW_FUNCTION(cfq_slice_async_show
, cfqd
->cfq_slice
[0], 1);
4567 SHOW_FUNCTION(cfq_slice_async_rq_show
, cfqd
->cfq_slice_async_rq
, 0);
4568 SHOW_FUNCTION(cfq_low_latency_show
, cfqd
->cfq_latency
, 0);
4569 SHOW_FUNCTION(cfq_target_latency_show
, cfqd
->cfq_target_latency
, 1);
4570 #undef SHOW_FUNCTION
4572 #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \
4573 static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \
4575 struct cfq_data *cfqd = e->elevator_data; \
4576 unsigned int __data; \
4577 int ret = cfq_var_store(&__data, (page), count); \
4578 if (__data < (MIN)) \
4580 else if (__data > (MAX)) \
4583 *(__PTR) = msecs_to_jiffies(__data); \
4585 *(__PTR) = __data; \
4588 STORE_FUNCTION(cfq_quantum_store
, &cfqd
->cfq_quantum
, 1, UINT_MAX
, 0);
4589 STORE_FUNCTION(cfq_fifo_expire_sync_store
, &cfqd
->cfq_fifo_expire
[1], 1,
4591 STORE_FUNCTION(cfq_fifo_expire_async_store
, &cfqd
->cfq_fifo_expire
[0], 1,
4593 STORE_FUNCTION(cfq_back_seek_max_store
, &cfqd
->cfq_back_max
, 0, UINT_MAX
, 0);
4594 STORE_FUNCTION(cfq_back_seek_penalty_store
, &cfqd
->cfq_back_penalty
, 1,
4596 STORE_FUNCTION(cfq_slice_idle_store
, &cfqd
->cfq_slice_idle
, 0, UINT_MAX
, 1);
4597 STORE_FUNCTION(cfq_group_idle_store
, &cfqd
->cfq_group_idle
, 0, UINT_MAX
, 1);
4598 STORE_FUNCTION(cfq_slice_sync_store
, &cfqd
->cfq_slice
[1], 1, UINT_MAX
, 1);
4599 STORE_FUNCTION(cfq_slice_async_store
, &cfqd
->cfq_slice
[0], 1, UINT_MAX
, 1);
4600 STORE_FUNCTION(cfq_slice_async_rq_store
, &cfqd
->cfq_slice_async_rq
, 1,
4602 STORE_FUNCTION(cfq_low_latency_store
, &cfqd
->cfq_latency
, 0, 1, 0);
4603 STORE_FUNCTION(cfq_target_latency_store
, &cfqd
->cfq_target_latency
, 1, UINT_MAX
, 1);
4604 #undef STORE_FUNCTION
4606 #define CFQ_ATTR(name) \
4607 __ATTR(name, S_IRUGO|S_IWUSR, cfq_##name##_show, cfq_##name##_store)
4609 static struct elv_fs_entry cfq_attrs
[] = {
4611 CFQ_ATTR(fifo_expire_sync
),
4612 CFQ_ATTR(fifo_expire_async
),
4613 CFQ_ATTR(back_seek_max
),
4614 CFQ_ATTR(back_seek_penalty
),
4615 CFQ_ATTR(slice_sync
),
4616 CFQ_ATTR(slice_async
),
4617 CFQ_ATTR(slice_async_rq
),
4618 CFQ_ATTR(slice_idle
),
4619 CFQ_ATTR(group_idle
),
4620 CFQ_ATTR(low_latency
),
4621 CFQ_ATTR(target_latency
),
4625 static struct elevator_type iosched_cfq
= {
4627 .elevator_merge_fn
= cfq_merge
,
4628 .elevator_merged_fn
= cfq_merged_request
,
4629 .elevator_merge_req_fn
= cfq_merged_requests
,
4630 .elevator_allow_merge_fn
= cfq_allow_merge
,
4631 .elevator_bio_merged_fn
= cfq_bio_merged
,
4632 .elevator_dispatch_fn
= cfq_dispatch_requests
,
4633 .elevator_add_req_fn
= cfq_insert_request
,
4634 .elevator_activate_req_fn
= cfq_activate_request
,
4635 .elevator_deactivate_req_fn
= cfq_deactivate_request
,
4636 .elevator_completed_req_fn
= cfq_completed_request
,
4637 .elevator_former_req_fn
= elv_rb_former_request
,
4638 .elevator_latter_req_fn
= elv_rb_latter_request
,
4639 .elevator_init_icq_fn
= cfq_init_icq
,
4640 .elevator_exit_icq_fn
= cfq_exit_icq
,
4641 .elevator_set_req_fn
= cfq_set_request
,
4642 .elevator_put_req_fn
= cfq_put_request
,
4643 .elevator_may_queue_fn
= cfq_may_queue
,
4644 .elevator_init_fn
= cfq_init_queue
,
4645 .elevator_exit_fn
= cfq_exit_queue
,
4646 .elevator_registered_fn
= cfq_registered_queue
,
4648 .icq_size
= sizeof(struct cfq_io_cq
),
4649 .icq_align
= __alignof__(struct cfq_io_cq
),
4650 .elevator_attrs
= cfq_attrs
,
4651 .elevator_name
= "cfq",
4652 .elevator_owner
= THIS_MODULE
,
4655 #ifdef CONFIG_CFQ_GROUP_IOSCHED
4656 static struct blkcg_policy blkcg_policy_cfq
= {
4657 .cftypes
= cfq_blkcg_files
,
4659 .cpd_alloc_fn
= cfq_cpd_alloc
,
4660 .cpd_init_fn
= cfq_cpd_init
,
4661 .cpd_free_fn
= cfq_cpd_free
,
4663 .pd_alloc_fn
= cfq_pd_alloc
,
4664 .pd_init_fn
= cfq_pd_init
,
4665 .pd_offline_fn
= cfq_pd_offline
,
4666 .pd_free_fn
= cfq_pd_free
,
4667 .pd_reset_stats_fn
= cfq_pd_reset_stats
,
4671 static int __init
cfq_init(void)
4676 * could be 0 on HZ < 1000 setups
4678 if (!cfq_slice_async
)
4679 cfq_slice_async
= 1;
4680 if (!cfq_slice_idle
)
4683 #ifdef CONFIG_CFQ_GROUP_IOSCHED
4684 if (!cfq_group_idle
)
4687 ret
= blkcg_policy_register(&blkcg_policy_cfq
);
4695 cfq_pool
= KMEM_CACHE(cfq_queue
, 0);
4699 ret
= elv_register(&iosched_cfq
);
4706 kmem_cache_destroy(cfq_pool
);
4708 #ifdef CONFIG_CFQ_GROUP_IOSCHED
4709 blkcg_policy_unregister(&blkcg_policy_cfq
);
4714 static void __exit
cfq_exit(void)
4716 #ifdef CONFIG_CFQ_GROUP_IOSCHED
4717 blkcg_policy_unregister(&blkcg_policy_cfq
);
4719 elv_unregister(&iosched_cfq
);
4720 kmem_cache_destroy(cfq_pool
);
4723 module_init(cfq_init
);
4724 module_exit(cfq_exit
);
4726 MODULE_AUTHOR("Jens Axboe");
4727 MODULE_LICENSE("GPL");
4728 MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler");