summaryrefslogtreecommitdiffstats
path: root/block/bfq-iosched.c
diff options
context:
space:
mode:
authorPaolo Valente <paolo.valente@linaro.org>2017-04-19 10:48:24 -0400
committerJens Axboe <axboe@fb.com>2017-04-19 10:48:24 -0400
commitea25da48086d3bbebf3a2eeff387ea00ed96f5c4 (patch)
tree1e7858910a647ae1a174ad019304bc3ffc2b5926 /block/bfq-iosched.c
parent6fa3e8d34204d532268ddb4dc5d2a904197c972d (diff)
block, bfq: split bfq-iosched.c into multiple source files
The BFQ I/O scheduler features an optimal fair-queuing (proportional-share) scheduling algorithm, enriched with several mechanisms to boost throughput and reduce latency for interactive and real-time applications. This makes BFQ a large and complex piece of code. This commit addresses this issue by splitting BFQ into three main, independent components, and by moving each component into a separate source file: 1. Main algorithm: handles the interaction with the kernel, and decides which requests to dispatch; it uses the following two further components to achieve its goals. 2. Scheduling engine (Hierarchical B-WF2Q+ scheduling algorithm): computes the schedule, using weights and budgets provided by the above component. 3. cgroups support: handles group operations (creation, destruction, move, ...). Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block/bfq-iosched.c')
-rw-r--r--block/bfq-iosched.c3663
1 files changed, 39 insertions, 3624 deletions
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 30bb8f905733..6d14f18c0d45 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -102,646 +102,18 @@
102#include "blk-mq.h" 102#include "blk-mq.h"
103#include "blk-mq-tag.h" 103#include "blk-mq-tag.h"
104#include "blk-mq-sched.h" 104#include "blk-mq-sched.h"
105#include <linux/blktrace_api.h> 105#include "bfq-iosched.h"
106#include <linux/hrtimer.h>
107#include <linux/blk-cgroup.h>
108
109#define BFQ_IOPRIO_CLASSES 3
110#define BFQ_CL_IDLE_TIMEOUT (HZ/5)
111
112#define BFQ_MIN_WEIGHT 1
113#define BFQ_MAX_WEIGHT 1000
114#define BFQ_WEIGHT_CONVERSION_COEFF 10
115
116#define BFQ_DEFAULT_QUEUE_IOPRIO 4
117
118#define BFQ_WEIGHT_LEGACY_DFL 100
119#define BFQ_DEFAULT_GRP_IOPRIO 0
120#define BFQ_DEFAULT_GRP_CLASS IOPRIO_CLASS_BE
121
122/*
123 * Soft real-time applications are extremely more latency sensitive
124 * than interactive ones. Over-raise the weight of the former to
125 * privilege them against the latter.
126 */
127#define BFQ_SOFTRT_WEIGHT_FACTOR 100
128
129struct bfq_entity;
130
131/**
132 * struct bfq_service_tree - per ioprio_class service tree.
133 *
134 * Each service tree represents a B-WF2Q+ scheduler on its own. Each
135 * ioprio_class has its own independent scheduler, and so its own
136 * bfq_service_tree. All the fields are protected by the queue lock
137 * of the containing bfqd.
138 */
139struct bfq_service_tree {
140 /* tree for active entities (i.e., those backlogged) */
141 struct rb_root active;
142 /* tree for idle entities (i.e., not backlogged, with V <= F_i)*/
143 struct rb_root idle;
144
145 /* idle entity with minimum F_i */
146 struct bfq_entity *first_idle;
147 /* idle entity with maximum F_i */
148 struct bfq_entity *last_idle;
149
150 /* scheduler virtual time */
151 u64 vtime;
152 /* scheduler weight sum; active and idle entities contribute to it */
153 unsigned long wsum;
154};
155
156/**
157 * struct bfq_sched_data - multi-class scheduler.
158 *
159 * bfq_sched_data is the basic scheduler queue. It supports three
160 * ioprio_classes, and can be used either as a toplevel queue or as an
161 * intermediate queue on a hierarchical setup. @next_in_service
162 * points to the active entity of the sched_data service trees that
163 * will be scheduled next. It is used to reduce the number of steps
164 * needed for each hierarchical-schedule update.
165 *
166 * The supported ioprio_classes are the same as in CFQ, in descending
167 * priority order, IOPRIO_CLASS_RT, IOPRIO_CLASS_BE, IOPRIO_CLASS_IDLE.
168 * Requests from higher priority queues are served before all the
169 * requests from lower priority queues; among requests of the same
170 * queue requests are served according to B-WF2Q+.
171 * All the fields are protected by the queue lock of the containing bfqd.
172 */
173struct bfq_sched_data {
174 /* entity in service */
175 struct bfq_entity *in_service_entity;
176 /* head-of-line entity (see comments above) */
177 struct bfq_entity *next_in_service;
178 /* array of service trees, one per ioprio_class */
179 struct bfq_service_tree service_tree[BFQ_IOPRIO_CLASSES];
180 /* last time CLASS_IDLE was served */
181 unsigned long bfq_class_idle_last_service;
182
183};
184
185/**
186 * struct bfq_weight_counter - counter of the number of all active entities
187 * with a given weight.
188 */
189struct bfq_weight_counter {
190 unsigned int weight; /* weight of the entities this counter refers to */
191 unsigned int num_active; /* nr of active entities with this weight */
192 /*
193 * Weights tree member (see bfq_data's @queue_weights_tree and
194 * @group_weights_tree)
195 */
196 struct rb_node weights_node;
197};
198
199/**
200 * struct bfq_entity - schedulable entity.
201 *
202 * A bfq_entity is used to represent either a bfq_queue (leaf node in the
203 * cgroup hierarchy) or a bfq_group into the upper level scheduler. Each
204 * entity belongs to the sched_data of the parent group in the cgroup
205 * hierarchy. Non-leaf entities have also their own sched_data, stored
206 * in @my_sched_data.
207 *
208 * Each entity stores independently its priority values; this would
209 * allow different weights on different devices, but this
210 * functionality is not exported to userspace by now. Priorities and
211 * weights are updated lazily, first storing the new values into the
212 * new_* fields, then setting the @prio_changed flag. As soon as
213 * there is a transition in the entity state that allows the priority
214 * update to take place the effective and the requested priority
215 * values are synchronized.
216 *
217 * Unless cgroups are used, the weight value is calculated from the
218 * ioprio to export the same interface as CFQ. When dealing with
219 * ``well-behaved'' queues (i.e., queues that do not spend too much
220 * time to consume their budget and have true sequential behavior, and
221 * when there are no external factors breaking anticipation) the
222 * relative weights at each level of the cgroups hierarchy should be
223 * guaranteed. All the fields are protected by the queue lock of the
224 * containing bfqd.
225 */
226struct bfq_entity {
227 /* service_tree member */
228 struct rb_node rb_node;
229 /* pointer to the weight counter associated with this entity */
230 struct bfq_weight_counter *weight_counter;
231
232 /*
233 * Flag, true if the entity is on a tree (either the active or
234 * the idle one of its service_tree) or is in service.
235 */
236 bool on_st;
237
238 /* B-WF2Q+ start and finish timestamps [sectors/weight] */
239 u64 start, finish;
240
241 /* tree the entity is enqueued into; %NULL if not on a tree */
242 struct rb_root *tree;
243
244 /*
245 * minimum start time of the (active) subtree rooted at this
246 * entity; used for O(log N) lookups into active trees
247 */
248 u64 min_start;
249
250 /* amount of service received during the last service slot */
251 int service;
252
253 /* budget, used also to calculate F_i: F_i = S_i + @budget / @weight */
254 int budget;
255
256 /* weight of the queue */
257 int weight;
258 /* next weight if a change is in progress */
259 int new_weight;
260
261 /* original weight, used to implement weight boosting */
262 int orig_weight;
263
264 /* parent entity, for hierarchical scheduling */
265 struct bfq_entity *parent;
266
267 /*
268 * For non-leaf nodes in the hierarchy, the associated
269 * scheduler queue, %NULL on leaf nodes.
270 */
271 struct bfq_sched_data *my_sched_data;
272 /* the scheduler queue this entity belongs to */
273 struct bfq_sched_data *sched_data;
274
275 /* flag, set to request a weight, ioprio or ioprio_class change */
276 int prio_changed;
277};
278
279struct bfq_group;
280
281/**
282 * struct bfq_ttime - per process thinktime stats.
283 */
284struct bfq_ttime {
285 /* completion time of the last request */
286 u64 last_end_request;
287
288 /* total process thinktime */
289 u64 ttime_total;
290 /* number of thinktime samples */
291 unsigned long ttime_samples;
292 /* average process thinktime */
293 u64 ttime_mean;
294};
295
296/**
297 * struct bfq_queue - leaf schedulable entity.
298 *
299 * A bfq_queue is a leaf request queue; it can be associated with an
300 * io_context or more, if it is async or shared between cooperating
301 * processes. @cgroup holds a reference to the cgroup, to be sure that it
302 * does not disappear while a bfqq still references it (mostly to avoid
303 * races between request issuing and task migration followed by cgroup
304 * destruction).
305 * All the fields are protected by the queue lock of the containing bfqd.
306 */
307struct bfq_queue {
308 /* reference counter */
309 int ref;
310 /* parent bfq_data */
311 struct bfq_data *bfqd;
312
313 /* current ioprio and ioprio class */
314 unsigned short ioprio, ioprio_class;
315 /* next ioprio and ioprio class if a change is in progress */
316 unsigned short new_ioprio, new_ioprio_class;
317
318 /*
319 * Shared bfq_queue if queue is cooperating with one or more
320 * other queues.
321 */
322 struct bfq_queue *new_bfqq;
323 /* request-position tree member (see bfq_group's @rq_pos_tree) */
324 struct rb_node pos_node;
325 /* request-position tree root (see bfq_group's @rq_pos_tree) */
326 struct rb_root *pos_root;
327
328 /* sorted list of pending requests */
329 struct rb_root sort_list;
330 /* if fifo isn't expired, next request to serve */
331 struct request *next_rq;
332 /* number of sync and async requests queued */
333 int queued[2];
334 /* number of requests currently allocated */
335 int allocated;
336 /* number of pending metadata requests */
337 int meta_pending;
338 /* fifo list of requests in sort_list */
339 struct list_head fifo;
340
341 /* entity representing this queue in the scheduler */
342 struct bfq_entity entity;
343
344 /* maximum budget allowed from the feedback mechanism */
345 int max_budget;
346 /* budget expiration (in jiffies) */
347 unsigned long budget_timeout;
348
349 /* number of requests on the dispatch list or inside driver */
350 int dispatched;
351
352 /* status flags */
353 unsigned long flags;
354
355 /* node for active/idle bfqq list inside parent bfqd */
356 struct list_head bfqq_list;
357
358 /* associated @bfq_ttime struct */
359 struct bfq_ttime ttime;
360
361 /* bit vector: a 1 for each seeky requests in history */
362 u32 seek_history;
363
364 /* node for the device's burst list */
365 struct hlist_node burst_list_node;
366
367 /* position of the last request enqueued */
368 sector_t last_request_pos;
369
370 /* Number of consecutive pairs of request completion and
371 * arrival, such that the queue becomes idle after the
372 * completion, but the next request arrives within an idle
373 * time slice; used only if the queue's IO_bound flag has been
374 * cleared.
375 */
376 unsigned int requests_within_timer;
377
378 /* pid of the process owning the queue, used for logging purposes */
379 pid_t pid;
380
381 /*
382 * Pointer to the bfq_io_cq owning the bfq_queue, set to %NULL
383 * if the queue is shared.
384 */
385 struct bfq_io_cq *bic;
386
387 /* current maximum weight-raising time for this queue */
388 unsigned long wr_cur_max_time;
389 /*
390 * Minimum time instant such that, only if a new request is
391 * enqueued after this time instant in an idle @bfq_queue with
392 * no outstanding requests, then the task associated with the
393 * queue it is deemed as soft real-time (see the comments on
394 * the function bfq_bfqq_softrt_next_start())
395 */
396 unsigned long soft_rt_next_start;
397 /*
398 * Start time of the current weight-raising period if
399 * the @bfq-queue is being weight-raised, otherwise
400 * finish time of the last weight-raising period.
401 */
402 unsigned long last_wr_start_finish;
403 /* factor by which the weight of this queue is multiplied */
404 unsigned int wr_coeff;
405 /*
406 * Time of the last transition of the @bfq_queue from idle to
407 * backlogged.
408 */
409 unsigned long last_idle_bklogged;
410 /*
411 * Cumulative service received from the @bfq_queue since the
412 * last transition from idle to backlogged.
413 */
414 unsigned long service_from_backlogged;
415
416 /*
417 * Value of wr start time when switching to soft rt
418 */
419 unsigned long wr_start_at_switch_to_srt;
420
421 unsigned long split_time; /* time of last split */
422};
423
424/**
425 * struct bfq_io_cq - per (request_queue, io_context) structure.
426 */
427struct bfq_io_cq {
428 /* associated io_cq structure */
429 struct io_cq icq; /* must be the first member */
430 /* array of two process queues, the sync and the async */
431 struct bfq_queue *bfqq[2];
432 /* per (request_queue, blkcg) ioprio */
433 int ioprio;
434#ifdef CONFIG_BFQ_GROUP_IOSCHED
435 uint64_t blkcg_serial_nr; /* the current blkcg serial */
436#endif
437 /*
438 * Snapshot of the idle window before merging; taken to
439 * remember this value while the queue is merged, so as to be
440 * able to restore it in case of split.
441 */
442 bool saved_idle_window;
443 /*
444 * Same purpose as the previous two fields for the I/O bound
445 * classification of a queue.
446 */
447 bool saved_IO_bound;
448
449 /*
450 * Same purpose as the previous fields for the value of the
451 * field keeping the queue's belonging to a large burst
452 */
453 bool saved_in_large_burst;
454 /*
455 * True if the queue belonged to a burst list before its merge
456 * with another cooperating queue.
457 */
458 bool was_in_burst_list;
459
460 /*
461 * Similar to previous fields: save wr information.
462 */
463 unsigned long saved_wr_coeff;
464 unsigned long saved_last_wr_start_finish;
465 unsigned long saved_wr_start_at_switch_to_srt;
466 unsigned int saved_wr_cur_max_time;
467 struct bfq_ttime saved_ttime;
468};
469
470enum bfq_device_speed {
471 BFQ_BFQD_FAST,
472 BFQ_BFQD_SLOW,
473};
474
475/**
476 * struct bfq_data - per-device data structure.
477 *
478 * All the fields are protected by @lock.
479 */
480struct bfq_data {
481 /* device request queue */
482 struct request_queue *queue;
483 /* dispatch queue */
484 struct list_head dispatch;
485
486 /* root bfq_group for the device */
487 struct bfq_group *root_group;
488
489 /*
490 * rbtree of weight counters of @bfq_queues, sorted by
491 * weight. Used to keep track of whether all @bfq_queues have
492 * the same weight. The tree contains one counter for each
493 * distinct weight associated to some active and not
494 * weight-raised @bfq_queue (see the comments to the functions
495 * bfq_weights_tree_[add|remove] for further details).
496 */
497 struct rb_root queue_weights_tree;
498 /*
499 * rbtree of non-queue @bfq_entity weight counters, sorted by
500 * weight. Used to keep track of whether all @bfq_groups have
501 * the same weight. The tree contains one counter for each
502 * distinct weight associated to some active @bfq_group (see
503 * the comments to the functions bfq_weights_tree_[add|remove]
504 * for further details).
505 */
506 struct rb_root group_weights_tree;
507
508 /*
509 * Number of bfq_queues containing requests (including the
510 * queue in service, even if it is idling).
511 */
512 int busy_queues;
513 /* number of weight-raised busy @bfq_queues */
514 int wr_busy_queues;
515 /* number of queued requests */
516 int queued;
517 /* number of requests dispatched and waiting for completion */
518 int rq_in_driver;
519
520 /*
521 * Maximum number of requests in driver in the last
522 * @hw_tag_samples completed requests.
523 */
524 int max_rq_in_driver;
525 /* number of samples used to calculate hw_tag */
526 int hw_tag_samples;
527 /* flag set to one if the driver is showing a queueing behavior */
528 int hw_tag;
529
530 /* number of budgets assigned */
531 int budgets_assigned;
532
533 /*
534 * Timer set when idling (waiting) for the next request from
535 * the queue in service.
536 */
537 struct hrtimer idle_slice_timer;
538
539 /* bfq_queue in service */
540 struct bfq_queue *in_service_queue;
541
542 /* on-disk position of the last served request */
543 sector_t last_position;
544
545 /* time of last request completion (ns) */
546 u64 last_completion;
547
548 /* time of first rq dispatch in current observation interval (ns) */
549 u64 first_dispatch;
550 /* time of last rq dispatch in current observation interval (ns) */
551 u64 last_dispatch;
552
553 /* beginning of the last budget */
554 ktime_t last_budget_start;
555 /* beginning of the last idle slice */
556 ktime_t last_idling_start;
557
558 /* number of samples in current observation interval */
559 int peak_rate_samples;
560 /* num of samples of seq dispatches in current observation interval */
561 u32 sequential_samples;
562 /* total num of sectors transferred in current observation interval */
563 u64 tot_sectors_dispatched;
564 /* max rq size seen during current observation interval (sectors) */
565 u32 last_rq_max_size;
566 /* time elapsed from first dispatch in current observ. interval (us) */
567 u64 delta_from_first;
568 /*
569 * Current estimate of the device peak rate, measured in
570 * [BFQ_RATE_SHIFT * sectors/usec]. The left-shift by
571 * BFQ_RATE_SHIFT is performed to increase precision in
572 * fixed-point calculations.
573 */
574 u32 peak_rate;
575
576 /* maximum budget allotted to a bfq_queue before rescheduling */
577 int bfq_max_budget;
578
579 /* list of all the bfq_queues active on the device */
580 struct list_head active_list;
581 /* list of all the bfq_queues idle on the device */
582 struct list_head idle_list;
583
584 /*
585 * Timeout for async/sync requests; when it fires, requests
586 * are served in fifo order.
587 */
588 u64 bfq_fifo_expire[2];
589 /* weight of backward seeks wrt forward ones */
590 unsigned int bfq_back_penalty;
591 /* maximum allowed backward seek */
592 unsigned int bfq_back_max;
593 /* maximum idling time */
594 u32 bfq_slice_idle;
595
596 /* user-configured max budget value (0 for auto-tuning) */
597 int bfq_user_max_budget;
598 /*
599 * Timeout for bfq_queues to consume their budget; used to
600 * prevent seeky queues from imposing long latencies to
601 * sequential or quasi-sequential ones (this also implies that
602 * seeky queues cannot receive guarantees in the service
603 * domain; after a timeout they are charged for the time they
604 * have been in service, to preserve fairness among them, but
605 * without service-domain guarantees).
606 */
607 unsigned int bfq_timeout;
608
609 /*
610 * Number of consecutive requests that must be issued within
611 * the idle time slice to set again idling to a queue which
612 * was marked as non-I/O-bound (see the definition of the
613 * IO_bound flag for further details).
614 */
615 unsigned int bfq_requests_within_timer;
616
617 /*
618 * Force device idling whenever needed to provide accurate
619 * service guarantees, without caring about throughput
620 * issues. CAVEAT: this may even increase latencies, in case
621 * of useless idling for processes that did stop doing I/O.
622 */
623 bool strict_guarantees;
624
625 /*
626 * Last time at which a queue entered the current burst of
627 * queues being activated shortly after each other; for more
628 * details about this and the following parameters related to
629 * a burst of activations, see the comments on the function
630 * bfq_handle_burst.
631 */
632 unsigned long last_ins_in_burst;
633 /*
634 * Reference time interval used to decide whether a queue has
635 * been activated shortly after @last_ins_in_burst.
636 */
637 unsigned long bfq_burst_interval;
638 /* number of queues in the current burst of queue activations */
639 int burst_size;
640
641 /* common parent entity for the queues in the burst */
642 struct bfq_entity *burst_parent_entity;
643 /* Maximum burst size above which the current queue-activation
644 * burst is deemed as 'large'.
645 */
646 unsigned long bfq_large_burst_thresh;
647 /* true if a large queue-activation burst is in progress */
648 bool large_burst;
649 /*
650 * Head of the burst list (as for the above fields, more
651 * details in the comments on the function bfq_handle_burst).
652 */
653 struct hlist_head burst_list;
654
655 /* if set to true, low-latency heuristics are enabled */
656 bool low_latency;
657 /*
658 * Maximum factor by which the weight of a weight-raised queue
659 * is multiplied.
660 */
661 unsigned int bfq_wr_coeff;
662 /* maximum duration of a weight-raising period (jiffies) */
663 unsigned int bfq_wr_max_time;
664
665 /* Maximum weight-raising duration for soft real-time processes */
666 unsigned int bfq_wr_rt_max_time;
667 /*
668 * Minimum idle period after which weight-raising may be
669 * reactivated for a queue (in jiffies).
670 */
671 unsigned int bfq_wr_min_idle_time;
672 /*
673 * Minimum period between request arrivals after which
674 * weight-raising may be reactivated for an already busy async
675 * queue (in jiffies).
676 */
677 unsigned long bfq_wr_min_inter_arr_async;
678
679 /* Max service-rate for a soft real-time queue, in sectors/sec */
680 unsigned int bfq_wr_max_softrt_rate;
681 /*
682 * Cached value of the product R*T, used for computing the
683 * maximum duration of weight raising automatically.
684 */
685 u64 RT_prod;
686 /* device-speed class for the low-latency heuristic */
687 enum bfq_device_speed device_speed;
688
689 /* fallback dummy bfqq for extreme OOM conditions */
690 struct bfq_queue oom_bfqq;
691
692 spinlock_t lock;
693
694 /*
695 * bic associated with the task issuing current bio for
696 * merging. This and the next field are used as a support to
697 * be able to perform the bic lookup, needed by bio-merge
698 * functions, before the scheduler lock is taken, and thus
699 * avoid taking the request-queue lock while the scheduler
700 * lock is being held.
701 */
702 struct bfq_io_cq *bio_bic;
703 /* bfqq associated with the task issuing current bio for merging */
704 struct bfq_queue *bio_bfqq;
705};
706
707enum bfqq_state_flags {
708 BFQQF_just_created = 0, /* queue just allocated */
709 BFQQF_busy, /* has requests or is in service */
710 BFQQF_wait_request, /* waiting for a request */
711 BFQQF_non_blocking_wait_rq, /*
712 * waiting for a request
713 * without idling the device
714 */
715 BFQQF_fifo_expire, /* FIFO checked in this slice */
716 BFQQF_idle_window, /* slice idling enabled */
717 BFQQF_sync, /* synchronous queue */
718 BFQQF_IO_bound, /*
719 * bfqq has timed-out at least once
720 * having consumed at most 2/10 of
721 * its budget
722 */
723 BFQQF_in_large_burst, /*
724 * bfqq activated in a large burst,
725 * see comments to bfq_handle_burst.
726 */
727 BFQQF_softrt_update, /*
728 * may need softrt-next-start
729 * update
730 */
731 BFQQF_coop, /* bfqq is shared */
732 BFQQF_split_coop /* shared bfqq will be split */
733};
734 106
735#define BFQ_BFQQ_FNS(name) \ 107#define BFQ_BFQQ_FNS(name) \
736static void bfq_mark_bfqq_##name(struct bfq_queue *bfqq) \ 108void bfq_mark_bfqq_##name(struct bfq_queue *bfqq) \
737{ \ 109{ \
738 __set_bit(BFQQF_##name, &(bfqq)->flags); \ 110 __set_bit(BFQQF_##name, &(bfqq)->flags); \
739} \ 111} \
740static void bfq_clear_bfqq_##name(struct bfq_queue *bfqq) \ 112void bfq_clear_bfqq_##name(struct bfq_queue *bfqq) \
741{ \ 113{ \
742 __clear_bit(BFQQF_##name, &(bfqq)->flags); \ 114 __clear_bit(BFQQF_##name, &(bfqq)->flags); \
743} \ 115} \
744static int bfq_bfqq_##name(const struct bfq_queue *bfqq) \ 116int bfq_bfqq_##name(const struct bfq_queue *bfqq) \
745{ \ 117{ \
746 return test_bit(BFQQF_##name, &(bfqq)->flags); \ 118 return test_bit(BFQQF_##name, &(bfqq)->flags); \
747} 119}
@@ -758,230 +130,7 @@ BFQ_BFQQ_FNS(in_large_burst);
758BFQ_BFQQ_FNS(coop); 130BFQ_BFQQ_FNS(coop);
759BFQ_BFQQ_FNS(split_coop); 131BFQ_BFQQ_FNS(split_coop);
760BFQ_BFQQ_FNS(softrt_update); 132BFQ_BFQQ_FNS(softrt_update);
761#undef BFQ_BFQQ_FNS 133#undef BFQ_BFQQ_FNS \
762
763/* Logging facilities. */
764#ifdef CONFIG_BFQ_GROUP_IOSCHED
765static struct bfq_group *bfqq_group(struct bfq_queue *bfqq);
766static struct blkcg_gq *bfqg_to_blkg(struct bfq_group *bfqg);
767
768#define bfq_log_bfqq(bfqd, bfqq, fmt, args...) do { \
769 char __pbuf[128]; \
770 \
771 blkg_path(bfqg_to_blkg(bfqq_group(bfqq)), __pbuf, sizeof(__pbuf)); \
772 blk_add_trace_msg((bfqd)->queue, "bfq%d%c %s " fmt, (bfqq)->pid, \
773 bfq_bfqq_sync((bfqq)) ? 'S' : 'A', \
774 __pbuf, ##args); \
775} while (0)
776
777#define bfq_log_bfqg(bfqd, bfqg, fmt, args...) do { \
778 char __pbuf[128]; \
779 \
780 blkg_path(bfqg_to_blkg(bfqg), __pbuf, sizeof(__pbuf)); \
781 blk_add_trace_msg((bfqd)->queue, "%s " fmt, __pbuf, ##args); \
782} while (0)
783
784#else /* CONFIG_BFQ_GROUP_IOSCHED */
785
786#define bfq_log_bfqq(bfqd, bfqq, fmt, args...) \
787 blk_add_trace_msg((bfqd)->queue, "bfq%d%c " fmt, (bfqq)->pid, \
788 bfq_bfqq_sync((bfqq)) ? 'S' : 'A', \
789 ##args)
790#define bfq_log_bfqg(bfqd, bfqg, fmt, args...) do {} while (0)
791
792#endif /* CONFIG_BFQ_GROUP_IOSCHED */
793
794#define bfq_log(bfqd, fmt, args...) \
795 blk_add_trace_msg((bfqd)->queue, "bfq " fmt, ##args)
796
797/* Expiration reasons. */
798enum bfqq_expiration {
799 BFQQE_TOO_IDLE = 0, /*
800 * queue has been idling for
801 * too long
802 */
803 BFQQE_BUDGET_TIMEOUT, /* budget took too long to be used */
804 BFQQE_BUDGET_EXHAUSTED, /* budget consumed */
805 BFQQE_NO_MORE_REQUESTS, /* the queue has no more requests */
806 BFQQE_PREEMPTED /* preemption in progress */
807};
808
809struct bfqg_stats {
810#ifdef CONFIG_BFQ_GROUP_IOSCHED
811 /* number of ios merged */
812 struct blkg_rwstat merged;
813 /* total time spent on device in ns, may not be accurate w/ queueing */
814 struct blkg_rwstat service_time;
815 /* total time spent waiting in scheduler queue in ns */
816 struct blkg_rwstat wait_time;
817 /* number of IOs queued up */
818 struct blkg_rwstat queued;
819 /* total disk time and nr sectors dispatched by this group */
820 struct blkg_stat time;
821 /* sum of number of ios queued across all samples */
822 struct blkg_stat avg_queue_size_sum;
823 /* count of samples taken for average */
824 struct blkg_stat avg_queue_size_samples;
825 /* how many times this group has been removed from service tree */
826 struct blkg_stat dequeue;
827 /* total time spent waiting for it to be assigned a timeslice. */
828 struct blkg_stat group_wait_time;
829 /* time spent idling for this blkcg_gq */
830 struct blkg_stat idle_time;
831 /* total time with empty current active q with other requests queued */
832 struct blkg_stat empty_time;
833 /* fields after this shouldn't be cleared on stat reset */
834 uint64_t start_group_wait_time;
835 uint64_t start_idle_time;
836 uint64_t start_empty_time;
837 uint16_t flags;
838#endif /* CONFIG_BFQ_GROUP_IOSCHED */
839};
840
841#ifdef CONFIG_BFQ_GROUP_IOSCHED
842
843/*
844 * struct bfq_group_data - per-blkcg storage for the blkio subsystem.
845 *
846 * @ps: @blkcg_policy_storage that this structure inherits
847 * @weight: weight of the bfq_group
848 */
849struct bfq_group_data {
850 /* must be the first member */
851 struct blkcg_policy_data pd;
852
853 unsigned int weight;
854};
855
856/**
857 * struct bfq_group - per (device, cgroup) data structure.
858 * @entity: schedulable entity to insert into the parent group sched_data.
859 * @sched_data: own sched_data, to contain child entities (they may be
860 * both bfq_queues and bfq_groups).
861 * @bfqd: the bfq_data for the device this group acts upon.
862 * @async_bfqq: array of async queues for all the tasks belonging to
863 * the group, one queue per ioprio value per ioprio_class,
864 * except for the idle class that has only one queue.
865 * @async_idle_bfqq: async queue for the idle class (ioprio is ignored).
866 * @my_entity: pointer to @entity, %NULL for the toplevel group; used
867 * to avoid too many special cases during group creation/
868 * migration.
869 * @stats: stats for this bfqg.
870 * @active_entities: number of active entities belonging to the group;
871 * unused for the root group. Used to know whether there
872 * are groups with more than one active @bfq_entity
873 * (see the comments to the function
874 * bfq_bfqq_may_idle()).
875 * @rq_pos_tree: rbtree sorted by next_request position, used when
876 * determining if two or more queues have interleaving
877 * requests (see bfq_find_close_cooperator()).
878 *
879 * Each (device, cgroup) pair has its own bfq_group, i.e., for each cgroup
880 * there is a set of bfq_groups, each one collecting the lower-level
881 * entities belonging to the group that are acting on the same device.
882 *
883 * Locking works as follows:
884 * o @bfqd is protected by the queue lock, RCU is used to access it
885 * from the readers.
886 * o All the other fields are protected by the @bfqd queue lock.
887 */
888struct bfq_group {
889 /* must be the first member */
890 struct blkg_policy_data pd;
891
892 struct bfq_entity entity;
893 struct bfq_sched_data sched_data;
894
895 void *bfqd;
896
897 struct bfq_queue *async_bfqq[2][IOPRIO_BE_NR];
898 struct bfq_queue *async_idle_bfqq;
899
900 struct bfq_entity *my_entity;
901
902 int active_entities;
903
904 struct rb_root rq_pos_tree;
905
906 struct bfqg_stats stats;
907};
908
909#else
910struct bfq_group {
911 struct bfq_sched_data sched_data;
912
913 struct bfq_queue *async_bfqq[2][IOPRIO_BE_NR];
914 struct bfq_queue *async_idle_bfqq;
915
916 struct rb_root rq_pos_tree;
917};
918#endif
919
920static struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity);
921
922static unsigned int bfq_class_idx(struct bfq_entity *entity)
923{
924 struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity);
925
926 return bfqq ? bfqq->ioprio_class - 1 :
927 BFQ_DEFAULT_GRP_CLASS - 1;
928}
929
930static struct bfq_service_tree *
931bfq_entity_service_tree(struct bfq_entity *entity)
932{
933 struct bfq_sched_data *sched_data = entity->sched_data;
934 unsigned int idx = bfq_class_idx(entity);
935
936 return sched_data->service_tree + idx;
937}
938
939static struct bfq_queue *bic_to_bfqq(struct bfq_io_cq *bic, bool is_sync)
940{
941 return bic->bfqq[is_sync];
942}
943
944static void bic_set_bfqq(struct bfq_io_cq *bic, struct bfq_queue *bfqq,
945 bool is_sync)
946{
947 bic->bfqq[is_sync] = bfqq;
948}
949
950static struct bfq_data *bic_to_bfqd(struct bfq_io_cq *bic)
951{
952 return bic->icq.q->elevator->elevator_data;
953}
954
955#ifdef CONFIG_BFQ_GROUP_IOSCHED
956
957static struct bfq_group *bfq_bfqq_to_bfqg(struct bfq_queue *bfqq)
958{
959 struct bfq_entity *group_entity = bfqq->entity.parent;
960
961 if (!group_entity)
962 group_entity = &bfqq->bfqd->root_group->entity;
963
964 return container_of(group_entity, struct bfq_group, entity);
965}
966
967#else
968
969static struct bfq_group *bfq_bfqq_to_bfqg(struct bfq_queue *bfqq)
970{
971 return bfqq->bfqd->root_group;
972}
973
974#endif
975
976static void bfq_check_ioprio_change(struct bfq_io_cq *bic, struct bio *bio);
977static void bfq_put_queue(struct bfq_queue *bfqq);
978static struct bfq_queue *bfq_get_queue(struct bfq_data *bfqd,
979 struct bio *bio, bool is_sync,
980 struct bfq_io_cq *bic);
981static void bfq_end_wr_async_queues(struct bfq_data *bfqd,
982 struct bfq_group *bfqg);
983static void bfq_put_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg);
984static void bfq_exit_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq);
985 134
986/* Expiration time of sync (0) and async (1) requests, in ns. */ 135/* Expiration time of sync (0) and async (1) requests, in ns. */
987static const u64 bfq_fifo_expire[2] = { NSEC_PER_SEC / 4, NSEC_PER_SEC / 8 }; 136static const u64 bfq_fifo_expire[2] = { NSEC_PER_SEC / 4, NSEC_PER_SEC / 8 };
@@ -1009,7 +158,7 @@ static const int bfq_default_max_budget = 16 * 1024;
1009static const int bfq_async_charge_factor = 10; 158static const int bfq_async_charge_factor = 10;
1010 159
1011/* Default timeout values, in jiffies, approximating CFQ defaults. */ 160/* Default timeout values, in jiffies, approximating CFQ defaults. */
1012static const int bfq_timeout = HZ / 8; 161const int bfq_timeout = HZ / 8;
1013 162
1014static struct kmem_cache *bfq_pool; 163static struct kmem_cache *bfq_pool;
1015 164
@@ -1085,12 +234,24 @@ static int T_slow[2];
1085static int T_fast[2]; 234static int T_fast[2];
1086static int device_speed_thresh[2]; 235static int device_speed_thresh[2];
1087 236
1088#define BFQ_SERVICE_TREE_INIT ((struct bfq_service_tree) \
1089 { RB_ROOT, RB_ROOT, NULL, NULL, 0, 0 })
1090
1091#define RQ_BIC(rq) ((struct bfq_io_cq *) (rq)->elv.priv[0]) 237#define RQ_BIC(rq) ((struct bfq_io_cq *) (rq)->elv.priv[0])
1092#define RQ_BFQQ(rq) ((rq)->elv.priv[1]) 238#define RQ_BFQQ(rq) ((rq)->elv.priv[1])
1093 239
240struct bfq_queue *bic_to_bfqq(struct bfq_io_cq *bic, bool is_sync)
241{
242 return bic->bfqq[is_sync];
243}
244
245void bic_set_bfqq(struct bfq_io_cq *bic, struct bfq_queue *bfqq, bool is_sync)
246{
247 bic->bfqq[is_sync] = bfqq;
248}
249
250struct bfq_data *bic_to_bfqd(struct bfq_io_cq *bic)
251{
252 return bic->icq.q->elevator->elevator_data;
253}
254
1094/** 255/**
1095 * icq_to_bic - convert iocontext queue structure to bfq_io_cq. 256 * icq_to_bic - convert iocontext queue structure to bfq_io_cq.
1096 * @icq: the iocontext queue. 257 * @icq: the iocontext queue.
@@ -1129,7 +290,7 @@ static struct bfq_io_cq *bfq_bic_lookup(struct bfq_data *bfqd,
1129 * Scheduler run of queue, if there are requests pending and no one in the 290 * Scheduler run of queue, if there are requests pending and no one in the
1130 * driver that will restart queueing. 291 * driver that will restart queueing.
1131 */ 292 */
1132static void bfq_schedule_dispatch(struct bfq_data *bfqd) 293void bfq_schedule_dispatch(struct bfq_data *bfqd)
1133{ 294{
1134 if (bfqd->queued != 0) { 295 if (bfqd->queued != 0) {
1135 bfq_log(bfqd, "schedule dispatch"); 296 bfq_log(bfqd, "schedule dispatch");
@@ -1137,2731 +298,6 @@ static void bfq_schedule_dispatch(struct bfq_data *bfqd)
1137 } 298 }
1138} 299}
1139 300
1140/**
1141 * bfq_gt - compare two timestamps.
1142 * @a: first ts.
1143 * @b: second ts.
1144 *
1145 * Return @a > @b, dealing with wrapping correctly.
1146 */
1147static int bfq_gt(u64 a, u64 b)
1148{
1149 return (s64)(a - b) > 0;
1150}
1151
1152static struct bfq_entity *bfq_root_active_entity(struct rb_root *tree)
1153{
1154 struct rb_node *node = tree->rb_node;
1155
1156 return rb_entry(node, struct bfq_entity, rb_node);
1157}
1158
1159static struct bfq_entity *bfq_lookup_next_entity(struct bfq_sched_data *sd);
1160
1161static bool bfq_update_parent_budget(struct bfq_entity *next_in_service);
1162
1163/**
1164 * bfq_update_next_in_service - update sd->next_in_service
1165 * @sd: sched_data for which to perform the update.
1166 * @new_entity: if not NULL, pointer to the entity whose activation,
1167 * requeueing or repositionig triggered the invocation of
1168 * this function.
1169 *
1170 * This function is called to update sd->next_in_service, which, in
1171 * its turn, may change as a consequence of the insertion or
1172 * extraction of an entity into/from one of the active trees of
1173 * sd. These insertions/extractions occur as a consequence of
1174 * activations/deactivations of entities, with some activations being
1175 * 'true' activations, and other activations being requeueings (i.e.,
1176 * implementing the second, requeueing phase of the mechanism used to
1177 * reposition an entity in its active tree; see comments on
1178 * __bfq_activate_entity and __bfq_requeue_entity for details). In
1179 * both the last two activation sub-cases, new_entity points to the
1180 * just activated or requeued entity.
1181 *
1182 * Returns true if sd->next_in_service changes in such a way that
1183 * entity->parent may become the next_in_service for its parent
1184 * entity.
1185 */
1186static bool bfq_update_next_in_service(struct bfq_sched_data *sd,
1187 struct bfq_entity *new_entity)
1188{
1189 struct bfq_entity *next_in_service = sd->next_in_service;
1190 bool parent_sched_may_change = false;
1191
1192 /*
1193 * If this update is triggered by the activation, requeueing
1194 * or repositiong of an entity that does not coincide with
1195 * sd->next_in_service, then a full lookup in the active tree
1196 * can be avoided. In fact, it is enough to check whether the
1197 * just-modified entity has a higher priority than
1198 * sd->next_in_service, or, even if it has the same priority
1199 * as sd->next_in_service, is eligible and has a lower virtual
1200 * finish time than sd->next_in_service. If this compound
1201 * condition holds, then the new entity becomes the new
1202 * next_in_service. Otherwise no change is needed.
1203 */
1204 if (new_entity && new_entity != sd->next_in_service) {
1205 /*
1206 * Flag used to decide whether to replace
1207 * sd->next_in_service with new_entity. Tentatively
1208 * set to true, and left as true if
1209 * sd->next_in_service is NULL.
1210 */
1211 bool replace_next = true;
1212
1213 /*
1214 * If there is already a next_in_service candidate
1215 * entity, then compare class priorities or timestamps
1216 * to decide whether to replace sd->service_tree with
1217 * new_entity.
1218 */
1219 if (next_in_service) {
1220 unsigned int new_entity_class_idx =
1221 bfq_class_idx(new_entity);
1222 struct bfq_service_tree *st =
1223 sd->service_tree + new_entity_class_idx;
1224
1225 /*
1226 * For efficiency, evaluate the most likely
1227 * sub-condition first.
1228 */
1229 replace_next =
1230 (new_entity_class_idx ==
1231 bfq_class_idx(next_in_service)
1232 &&
1233 !bfq_gt(new_entity->start, st->vtime)
1234 &&
1235 bfq_gt(next_in_service->finish,
1236 new_entity->finish))
1237 ||
1238 new_entity_class_idx <
1239 bfq_class_idx(next_in_service);
1240 }
1241
1242 if (replace_next)
1243 next_in_service = new_entity;
1244 } else /* invoked because of a deactivation: lookup needed */
1245 next_in_service = bfq_lookup_next_entity(sd);
1246
1247 if (next_in_service) {
1248 parent_sched_may_change = !sd->next_in_service ||
1249 bfq_update_parent_budget(next_in_service);
1250 }
1251
1252 sd->next_in_service = next_in_service;
1253
1254 if (!next_in_service)
1255 return parent_sched_may_change;
1256
1257 return parent_sched_may_change;
1258}
1259
1260#ifdef CONFIG_BFQ_GROUP_IOSCHED
1261/* both next loops stop at one of the child entities of the root group */
1262#define for_each_entity(entity) \
1263 for (; entity ; entity = entity->parent)
1264
1265/*
1266 * For each iteration, compute parent in advance, so as to be safe if
1267 * entity is deallocated during the iteration. Such a deallocation may
1268 * happen as a consequence of a bfq_put_queue that frees the bfq_queue
1269 * containing entity.
1270 */
1271#define for_each_entity_safe(entity, parent) \
1272 for (; entity && ({ parent = entity->parent; 1; }); entity = parent)
1273
1274/*
1275 * Returns true if this budget changes may let next_in_service->parent
1276 * become the next_in_service entity for its parent entity.
1277 */
1278static bool bfq_update_parent_budget(struct bfq_entity *next_in_service)
1279{
1280 struct bfq_entity *bfqg_entity;
1281 struct bfq_group *bfqg;
1282 struct bfq_sched_data *group_sd;
1283 bool ret = false;
1284
1285 group_sd = next_in_service->sched_data;
1286
1287 bfqg = container_of(group_sd, struct bfq_group, sched_data);
1288 /*
1289 * bfq_group's my_entity field is not NULL only if the group
1290 * is not the root group. We must not touch the root entity
1291 * as it must never become an in-service entity.
1292 */
1293 bfqg_entity = bfqg->my_entity;
1294 if (bfqg_entity) {
1295 if (bfqg_entity->budget > next_in_service->budget)
1296 ret = true;
1297 bfqg_entity->budget = next_in_service->budget;
1298 }
1299
1300 return ret;
1301}
1302
1303/*
1304 * This function tells whether entity stops being a candidate for next
1305 * service, according to the following logic.
1306 *
1307 * This function is invoked for an entity that is about to be set in
1308 * service. If such an entity is a queue, then the entity is no longer
1309 * a candidate for next service (i.e, a candidate entity to serve
1310 * after the in-service entity is expired). The function then returns
1311 * true.
1312 *
1313 * In contrast, the entity could stil be a candidate for next service
1314 * if it is not a queue, and has more than one child. In fact, even if
1315 * one of its children is about to be set in service, other children
1316 * may still be the next to serve. As a consequence, a non-queue
1317 * entity is not a candidate for next-service only if it has only one
1318 * child. And only if this condition holds, then the function returns
1319 * true for a non-queue entity.
1320 */
1321static bool bfq_no_longer_next_in_service(struct bfq_entity *entity)
1322{
1323 struct bfq_group *bfqg;
1324
1325 if (bfq_entity_to_bfqq(entity))
1326 return true;
1327
1328 bfqg = container_of(entity, struct bfq_group, entity);
1329
1330 if (bfqg->active_entities == 1)
1331 return true;
1332
1333 return false;
1334}
1335
1336#else /* CONFIG_BFQ_GROUP_IOSCHED */
1337/*
1338 * Next two macros are fake loops when cgroups support is not
1339 * enabled. I fact, in such a case, there is only one level to go up
1340 * (to reach the root group).
1341 */
1342#define for_each_entity(entity) \
1343 for (; entity ; entity = NULL)
1344
1345#define for_each_entity_safe(entity, parent) \
1346 for (parent = NULL; entity ; entity = parent)
1347
1348static bool bfq_update_parent_budget(struct bfq_entity *next_in_service)
1349{
1350 return false;
1351}
1352
1353static bool bfq_no_longer_next_in_service(struct bfq_entity *entity)
1354{
1355 return true;
1356}
1357
1358#endif /* CONFIG_BFQ_GROUP_IOSCHED */
1359
1360/*
1361 * Shift for timestamp calculations. This actually limits the maximum
1362 * service allowed in one timestamp delta (small shift values increase it),
1363 * the maximum total weight that can be used for the queues in the system
1364 * (big shift values increase it), and the period of virtual time
1365 * wraparounds.
1366 */
1367#define WFQ_SERVICE_SHIFT 22
1368
1369static struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity)
1370{
1371 struct bfq_queue *bfqq = NULL;
1372
1373 if (!entity->my_sched_data)
1374 bfqq = container_of(entity, struct bfq_queue, entity);
1375
1376 return bfqq;
1377}
1378
1379
1380/**
1381 * bfq_delta - map service into the virtual time domain.
1382 * @service: amount of service.
1383 * @weight: scale factor (weight of an entity or weight sum).
1384 */
1385static u64 bfq_delta(unsigned long service, unsigned long weight)
1386{
1387 u64 d = (u64)service << WFQ_SERVICE_SHIFT;
1388
1389 do_div(d, weight);
1390 return d;
1391}
1392
1393/**
1394 * bfq_calc_finish - assign the finish time to an entity.
1395 * @entity: the entity to act upon.
1396 * @service: the service to be charged to the entity.
1397 */
1398static void bfq_calc_finish(struct bfq_entity *entity, unsigned long service)
1399{
1400 struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity);
1401
1402 entity->finish = entity->start +
1403 bfq_delta(service, entity->weight);
1404
1405 if (bfqq) {
1406 bfq_log_bfqq(bfqq->bfqd, bfqq,
1407 "calc_finish: serv %lu, w %d",
1408 service, entity->weight);
1409 bfq_log_bfqq(bfqq->bfqd, bfqq,
1410 "calc_finish: start %llu, finish %llu, delta %llu",
1411 entity->start, entity->finish,
1412 bfq_delta(service, entity->weight));
1413 }
1414}
1415
1416/**
1417 * bfq_entity_of - get an entity from a node.
1418 * @node: the node field of the entity.
1419 *
1420 * Convert a node pointer to the relative entity. This is used only
1421 * to simplify the logic of some functions and not as the generic
1422 * conversion mechanism because, e.g., in the tree walking functions,
1423 * the check for a %NULL value would be redundant.
1424 */
1425static struct bfq_entity *bfq_entity_of(struct rb_node *node)
1426{
1427 struct bfq_entity *entity = NULL;
1428
1429 if (node)
1430 entity = rb_entry(node, struct bfq_entity, rb_node);
1431
1432 return entity;
1433}
1434
1435/**
1436 * bfq_extract - remove an entity from a tree.
1437 * @root: the tree root.
1438 * @entity: the entity to remove.
1439 */
1440static void bfq_extract(struct rb_root *root, struct bfq_entity *entity)
1441{
1442 entity->tree = NULL;
1443 rb_erase(&entity->rb_node, root);
1444}
1445
1446/**
1447 * bfq_idle_extract - extract an entity from the idle tree.
1448 * @st: the service tree of the owning @entity.
1449 * @entity: the entity being removed.
1450 */
1451static void bfq_idle_extract(struct bfq_service_tree *st,
1452 struct bfq_entity *entity)
1453{
1454 struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity);
1455 struct rb_node *next;
1456
1457 if (entity == st->first_idle) {
1458 next = rb_next(&entity->rb_node);
1459 st->first_idle = bfq_entity_of(next);
1460 }
1461
1462 if (entity == st->last_idle) {
1463 next = rb_prev(&entity->rb_node);
1464 st->last_idle = bfq_entity_of(next);
1465 }
1466
1467 bfq_extract(&st->idle, entity);
1468
1469 if (bfqq)
1470 list_del(&bfqq->bfqq_list);
1471}
1472
1473/**
1474 * bfq_insert - generic tree insertion.
1475 * @root: tree root.
1476 * @entity: entity to insert.
1477 *
1478 * This is used for the idle and the active tree, since they are both
1479 * ordered by finish time.
1480 */
1481static void bfq_insert(struct rb_root *root, struct bfq_entity *entity)
1482{
1483 struct bfq_entity *entry;
1484 struct rb_node **node = &root->rb_node;
1485 struct rb_node *parent = NULL;
1486
1487 while (*node) {
1488 parent = *node;
1489 entry = rb_entry(parent, struct bfq_entity, rb_node);
1490
1491 if (bfq_gt(entry->finish, entity->finish))
1492 node = &parent->rb_left;
1493 else
1494 node = &parent->rb_right;
1495 }
1496
1497 rb_link_node(&entity->rb_node, parent, node);
1498 rb_insert_color(&entity->rb_node, root);
1499
1500 entity->tree = root;
1501}
1502
1503/**
1504 * bfq_update_min - update the min_start field of a entity.
1505 * @entity: the entity to update.
1506 * @node: one of its children.
1507 *
1508 * This function is called when @entity may store an invalid value for
1509 * min_start due to updates to the active tree. The function assumes
1510 * that the subtree rooted at @node (which may be its left or its right
1511 * child) has a valid min_start value.
1512 */
1513static void bfq_update_min(struct bfq_entity *entity, struct rb_node *node)
1514{
1515 struct bfq_entity *child;
1516
1517 if (node) {
1518 child = rb_entry(node, struct bfq_entity, rb_node);
1519 if (bfq_gt(entity->min_start, child->min_start))
1520 entity->min_start = child->min_start;
1521 }
1522}
1523
1524/**
1525 * bfq_update_active_node - recalculate min_start.
1526 * @node: the node to update.
1527 *
1528 * @node may have changed position or one of its children may have moved,
1529 * this function updates its min_start value. The left and right subtrees
1530 * are assumed to hold a correct min_start value.
1531 */
1532static void bfq_update_active_node(struct rb_node *node)
1533{
1534 struct bfq_entity *entity = rb_entry(node, struct bfq_entity, rb_node);
1535
1536 entity->min_start = entity->start;
1537 bfq_update_min(entity, node->rb_right);
1538 bfq_update_min(entity, node->rb_left);
1539}
1540
1541/**
1542 * bfq_update_active_tree - update min_start for the whole active tree.
1543 * @node: the starting node.
1544 *
1545 * @node must be the deepest modified node after an update. This function
1546 * updates its min_start using the values held by its children, assuming
1547 * that they did not change, and then updates all the nodes that may have
1548 * changed in the path to the root. The only nodes that may have changed
1549 * are the ones in the path or their siblings.
1550 */
1551static void bfq_update_active_tree(struct rb_node *node)
1552{
1553 struct rb_node *parent;
1554
1555up:
1556 bfq_update_active_node(node);
1557
1558 parent = rb_parent(node);
1559 if (!parent)
1560 return;
1561
1562 if (node == parent->rb_left && parent->rb_right)
1563 bfq_update_active_node(parent->rb_right);
1564 else if (parent->rb_left)
1565 bfq_update_active_node(parent->rb_left);
1566
1567 node = parent;
1568 goto up;
1569}
1570
1571static void bfq_weights_tree_add(struct bfq_data *bfqd,
1572 struct bfq_entity *entity,
1573 struct rb_root *root);
1574
1575static void bfq_weights_tree_remove(struct bfq_data *bfqd,
1576 struct bfq_entity *entity,
1577 struct rb_root *root);
1578
1579
1580/**
1581 * bfq_active_insert - insert an entity in the active tree of its
1582 * group/device.
1583 * @st: the service tree of the entity.
1584 * @entity: the entity being inserted.
1585 *
1586 * The active tree is ordered by finish time, but an extra key is kept
1587 * per each node, containing the minimum value for the start times of
1588 * its children (and the node itself), so it's possible to search for
1589 * the eligible node with the lowest finish time in logarithmic time.
1590 */
1591static void bfq_active_insert(struct bfq_service_tree *st,
1592 struct bfq_entity *entity)
1593{
1594 struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity);
1595 struct rb_node *node = &entity->rb_node;
1596#ifdef CONFIG_BFQ_GROUP_IOSCHED
1597 struct bfq_sched_data *sd = NULL;
1598 struct bfq_group *bfqg = NULL;
1599 struct bfq_data *bfqd = NULL;
1600#endif
1601
1602 bfq_insert(&st->active, entity);
1603
1604 if (node->rb_left)
1605 node = node->rb_left;
1606 else if (node->rb_right)
1607 node = node->rb_right;
1608
1609 bfq_update_active_tree(node);
1610
1611#ifdef CONFIG_BFQ_GROUP_IOSCHED
1612 sd = entity->sched_data;
1613 bfqg = container_of(sd, struct bfq_group, sched_data);
1614 bfqd = (struct bfq_data *)bfqg->bfqd;
1615#endif
1616 if (bfqq)
1617 list_add(&bfqq->bfqq_list, &bfqq->bfqd->active_list);
1618#ifdef CONFIG_BFQ_GROUP_IOSCHED
1619 else /* bfq_group */
1620 bfq_weights_tree_add(bfqd, entity, &bfqd->group_weights_tree);
1621
1622 if (bfqg != bfqd->root_group)
1623 bfqg->active_entities++;
1624#endif
1625}
1626
1627/**
1628 * bfq_ioprio_to_weight - calc a weight from an ioprio.
1629 * @ioprio: the ioprio value to convert.
1630 */
1631static unsigned short bfq_ioprio_to_weight(int ioprio)
1632{
1633 return (IOPRIO_BE_NR - ioprio) * BFQ_WEIGHT_CONVERSION_COEFF;
1634}
1635
1636/**
1637 * bfq_weight_to_ioprio - calc an ioprio from a weight.
1638 * @weight: the weight value to convert.
1639 *
1640 * To preserve as much as possible the old only-ioprio user interface,
1641 * 0 is used as an escape ioprio value for weights (numerically) equal or
1642 * larger than IOPRIO_BE_NR * BFQ_WEIGHT_CONVERSION_COEFF.
1643 */
1644static unsigned short bfq_weight_to_ioprio(int weight)
1645{
1646 return max_t(int, 0,
1647 IOPRIO_BE_NR * BFQ_WEIGHT_CONVERSION_COEFF - weight);
1648}
1649
1650static void bfq_get_entity(struct bfq_entity *entity)
1651{
1652 struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity);
1653
1654 if (bfqq) {
1655 bfqq->ref++;
1656 bfq_log_bfqq(bfqq->bfqd, bfqq, "get_entity: %p %d",
1657 bfqq, bfqq->ref);
1658 }
1659}
1660
1661/**
1662 * bfq_find_deepest - find the deepest node that an extraction can modify.
1663 * @node: the node being removed.
1664 *
1665 * Do the first step of an extraction in an rb tree, looking for the
1666 * node that will replace @node, and returning the deepest node that
1667 * the following modifications to the tree can touch. If @node is the
1668 * last node in the tree return %NULL.
1669 */
1670static struct rb_node *bfq_find_deepest(struct rb_node *node)
1671{
1672 struct rb_node *deepest;
1673
1674 if (!node->rb_right && !node->rb_left)
1675 deepest = rb_parent(node);
1676 else if (!node->rb_right)
1677 deepest = node->rb_left;
1678 else if (!node->rb_left)
1679 deepest = node->rb_right;
1680 else {
1681 deepest = rb_next(node);
1682 if (deepest->rb_right)
1683 deepest = deepest->rb_right;
1684 else if (rb_parent(deepest) != node)
1685 deepest = rb_parent(deepest);
1686 }
1687
1688 return deepest;
1689}
1690
1691/**
1692 * bfq_active_extract - remove an entity from the active tree.
1693 * @st: the service_tree containing the tree.
1694 * @entity: the entity being removed.
1695 */
1696static void bfq_active_extract(struct bfq_service_tree *st,
1697 struct bfq_entity *entity)
1698{
1699 struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity);
1700 struct rb_node *node;
1701#ifdef CONFIG_BFQ_GROUP_IOSCHED
1702 struct bfq_sched_data *sd = NULL;
1703 struct bfq_group *bfqg = NULL;
1704 struct bfq_data *bfqd = NULL;
1705#endif
1706
1707 node = bfq_find_deepest(&entity->rb_node);
1708 bfq_extract(&st->active, entity);
1709
1710 if (node)
1711 bfq_update_active_tree(node);
1712
1713#ifdef CONFIG_BFQ_GROUP_IOSCHED
1714 sd = entity->sched_data;
1715 bfqg = container_of(sd, struct bfq_group, sched_data);
1716 bfqd = (struct bfq_data *)bfqg->bfqd;
1717#endif
1718 if (bfqq)
1719 list_del(&bfqq->bfqq_list);
1720#ifdef CONFIG_BFQ_GROUP_IOSCHED
1721 else /* bfq_group */
1722 bfq_weights_tree_remove(bfqd, entity,
1723 &bfqd->group_weights_tree);
1724
1725 if (bfqg != bfqd->root_group)
1726 bfqg->active_entities--;
1727#endif
1728}
1729
1730/**
1731 * bfq_idle_insert - insert an entity into the idle tree.
1732 * @st: the service tree containing the tree.
1733 * @entity: the entity to insert.
1734 */
1735static void bfq_idle_insert(struct bfq_service_tree *st,
1736 struct bfq_entity *entity)
1737{
1738 struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity);
1739 struct bfq_entity *first_idle = st->first_idle;
1740 struct bfq_entity *last_idle = st->last_idle;
1741
1742 if (!first_idle || bfq_gt(first_idle->finish, entity->finish))
1743 st->first_idle = entity;
1744 if (!last_idle || bfq_gt(entity->finish, last_idle->finish))
1745 st->last_idle = entity;
1746
1747 bfq_insert(&st->idle, entity);
1748
1749 if (bfqq)
1750 list_add(&bfqq->bfqq_list, &bfqq->bfqd->idle_list);
1751}
1752
1753/**
1754 * bfq_forget_entity - do not consider entity any longer for scheduling
1755 * @st: the service tree.
1756 * @entity: the entity being removed.
1757 * @is_in_service: true if entity is currently the in-service entity.
1758 *
1759 * Forget everything about @entity. In addition, if entity represents
1760 * a queue, and the latter is not in service, then release the service
1761 * reference to the queue (the one taken through bfq_get_entity). In
1762 * fact, in this case, there is really no more service reference to
1763 * the queue, as the latter is also outside any service tree. If,
1764 * instead, the queue is in service, then __bfq_bfqd_reset_in_service
1765 * will take care of putting the reference when the queue finally
1766 * stops being served.
1767 */
1768static void bfq_forget_entity(struct bfq_service_tree *st,
1769 struct bfq_entity *entity,
1770 bool is_in_service)
1771{
1772 struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity);
1773
1774 entity->on_st = false;
1775 st->wsum -= entity->weight;
1776 if (bfqq && !is_in_service)
1777 bfq_put_queue(bfqq);
1778}
1779
1780/**
1781 * bfq_put_idle_entity - release the idle tree ref of an entity.
1782 * @st: service tree for the entity.
1783 * @entity: the entity being released.
1784 */
1785static void bfq_put_idle_entity(struct bfq_service_tree *st,
1786 struct bfq_entity *entity)
1787{
1788 bfq_idle_extract(st, entity);
1789 bfq_forget_entity(st, entity,
1790 entity == entity->sched_data->in_service_entity);
1791}
1792
1793/**
1794 * bfq_forget_idle - update the idle tree if necessary.
1795 * @st: the service tree to act upon.
1796 *
1797 * To preserve the global O(log N) complexity we only remove one entry here;
1798 * as the idle tree will not grow indefinitely this can be done safely.
1799 */
1800static void bfq_forget_idle(struct bfq_service_tree *st)
1801{
1802 struct bfq_entity *first_idle = st->first_idle;
1803 struct bfq_entity *last_idle = st->last_idle;
1804
1805 if (RB_EMPTY_ROOT(&st->active) && last_idle &&
1806 !bfq_gt(last_idle->finish, st->vtime)) {
1807 /*
1808 * Forget the whole idle tree, increasing the vtime past
1809 * the last finish time of idle entities.
1810 */
1811 st->vtime = last_idle->finish;
1812 }
1813
1814 if (first_idle && !bfq_gt(first_idle->finish, st->vtime))
1815 bfq_put_idle_entity(st, first_idle);
1816}
1817
1818static struct bfq_service_tree *
1819__bfq_entity_update_weight_prio(struct bfq_service_tree *old_st,
1820 struct bfq_entity *entity)
1821{
1822 struct bfq_service_tree *new_st = old_st;
1823
1824 if (entity->prio_changed) {
1825 struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity);
1826 unsigned int prev_weight, new_weight;
1827 struct bfq_data *bfqd = NULL;
1828 struct rb_root *root;
1829#ifdef CONFIG_BFQ_GROUP_IOSCHED
1830 struct bfq_sched_data *sd;
1831 struct bfq_group *bfqg;
1832#endif
1833
1834 if (bfqq)
1835 bfqd = bfqq->bfqd;
1836#ifdef CONFIG_BFQ_GROUP_IOSCHED
1837 else {
1838 sd = entity->my_sched_data;
1839 bfqg = container_of(sd, struct bfq_group, sched_data);
1840 bfqd = (struct bfq_data *)bfqg->bfqd;
1841 }
1842#endif
1843
1844 old_st->wsum -= entity->weight;
1845
1846 if (entity->new_weight != entity->orig_weight) {
1847 if (entity->new_weight < BFQ_MIN_WEIGHT ||
1848 entity->new_weight > BFQ_MAX_WEIGHT) {
1849 pr_crit("update_weight_prio: new_weight %d\n",
1850 entity->new_weight);
1851 if (entity->new_weight < BFQ_MIN_WEIGHT)
1852 entity->new_weight = BFQ_MIN_WEIGHT;
1853 else
1854 entity->new_weight = BFQ_MAX_WEIGHT;
1855 }
1856 entity->orig_weight = entity->new_weight;
1857 if (bfqq)
1858 bfqq->ioprio =
1859 bfq_weight_to_ioprio(entity->orig_weight);
1860 }
1861
1862 if (bfqq)
1863 bfqq->ioprio_class = bfqq->new_ioprio_class;
1864 entity->prio_changed = 0;
1865
1866 /*
1867 * NOTE: here we may be changing the weight too early,
1868 * this will cause unfairness. The correct approach
1869 * would have required additional complexity to defer
1870 * weight changes to the proper time instants (i.e.,
1871 * when entity->finish <= old_st->vtime).
1872 */
1873 new_st = bfq_entity_service_tree(entity);
1874
1875 prev_weight = entity->weight;
1876 new_weight = entity->orig_weight *
1877 (bfqq ? bfqq->wr_coeff : 1);
1878 /*
1879 * If the weight of the entity changes, remove the entity
1880 * from its old weight counter (if there is a counter
1881 * associated with the entity), and add it to the counter
1882 * associated with its new weight.
1883 */
1884 if (prev_weight != new_weight) {
1885 root = bfqq ? &bfqd->queue_weights_tree :
1886 &bfqd->group_weights_tree;
1887 bfq_weights_tree_remove(bfqd, entity, root);
1888 }
1889 entity->weight = new_weight;
1890 /*
1891 * Add the entity to its weights tree only if it is
1892 * not associated with a weight-raised queue.
1893 */
1894 if (prev_weight != new_weight &&
1895 (bfqq ? bfqq->wr_coeff == 1 : 1))
1896 /* If we get here, root has been initialized. */
1897 bfq_weights_tree_add(bfqd, entity, root);
1898
1899 new_st->wsum += entity->weight;
1900
1901 if (new_st != old_st)
1902 entity->start = new_st->vtime;
1903 }
1904
1905 return new_st;
1906}
1907
1908static void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg);
1909static struct bfq_group *bfqq_group(struct bfq_queue *bfqq);
1910
1911/**
1912 * bfq_bfqq_served - update the scheduler status after selection for
1913 * service.
1914 * @bfqq: the queue being served.
1915 * @served: bytes to transfer.
1916 *
1917 * NOTE: this can be optimized, as the timestamps of upper level entities
1918 * are synchronized every time a new bfqq is selected for service. By now,
1919 * we keep it to better check consistency.
1920 */
1921static void bfq_bfqq_served(struct bfq_queue *bfqq, int served)
1922{
1923 struct bfq_entity *entity = &bfqq->entity;
1924 struct bfq_service_tree *st;
1925
1926 for_each_entity(entity) {
1927 st = bfq_entity_service_tree(entity);
1928
1929 entity->service += served;
1930
1931 st->vtime += bfq_delta(served, st->wsum);
1932 bfq_forget_idle(st);
1933 }
1934 bfqg_stats_set_start_empty_time(bfqq_group(bfqq));
1935 bfq_log_bfqq(bfqq->bfqd, bfqq, "bfqq_served %d secs", served);
1936}
1937
1938/**
1939 * bfq_bfqq_charge_time - charge an amount of service equivalent to the length
1940 * of the time interval during which bfqq has been in
1941 * service.
1942 * @bfqd: the device
1943 * @bfqq: the queue that needs a service update.
1944 * @time_ms: the amount of time during which the queue has received service
1945 *
1946 * If a queue does not consume its budget fast enough, then providing
1947 * the queue with service fairness may impair throughput, more or less
1948 * severely. For this reason, queues that consume their budget slowly
1949 * are provided with time fairness instead of service fairness. This
1950 * goal is achieved through the BFQ scheduling engine, even if such an
1951 * engine works in the service, and not in the time domain. The trick
1952 * is charging these queues with an inflated amount of service, equal
1953 * to the amount of service that they would have received during their
1954 * service slot if they had been fast, i.e., if their requests had
1955 * been dispatched at a rate equal to the estimated peak rate.
1956 *
1957 * It is worth noting that time fairness can cause important
1958 * distortions in terms of bandwidth distribution, on devices with
1959 * internal queueing. The reason is that I/O requests dispatched
1960 * during the service slot of a queue may be served after that service
1961 * slot is finished, and may have a total processing time loosely
1962 * correlated with the duration of the service slot. This is
1963 * especially true for short service slots.
1964 */
1965static void bfq_bfqq_charge_time(struct bfq_data *bfqd, struct bfq_queue *bfqq,
1966 unsigned long time_ms)
1967{
1968 struct bfq_entity *entity = &bfqq->entity;
1969 int tot_serv_to_charge = entity->service;
1970 unsigned int timeout_ms = jiffies_to_msecs(bfq_timeout);
1971
1972 if (time_ms > 0 && time_ms < timeout_ms)
1973 tot_serv_to_charge =
1974 (bfqd->bfq_max_budget * time_ms) / timeout_ms;
1975
1976 if (tot_serv_to_charge < entity->service)
1977 tot_serv_to_charge = entity->service;
1978
1979 /* Increase budget to avoid inconsistencies */
1980 if (tot_serv_to_charge > entity->budget)
1981 entity->budget = tot_serv_to_charge;
1982
1983 bfq_bfqq_served(bfqq,
1984 max_t(int, 0, tot_serv_to_charge - entity->service));
1985}
1986
1987static void bfq_update_fin_time_enqueue(struct bfq_entity *entity,
1988 struct bfq_service_tree *st,
1989 bool backshifted)
1990{
1991 struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity);
1992
1993 st = __bfq_entity_update_weight_prio(st, entity);
1994 bfq_calc_finish(entity, entity->budget);
1995
1996 /*
1997 * If some queues enjoy backshifting for a while, then their
1998 * (virtual) finish timestamps may happen to become lower and
1999 * lower than the system virtual time. In particular, if
2000 * these queues often happen to be idle for short time
2001 * periods, and during such time periods other queues with
2002 * higher timestamps happen to be busy, then the backshifted
2003 * timestamps of the former queues can become much lower than
2004 * the system virtual time. In fact, to serve the queues with
2005 * higher timestamps while the ones with lower timestamps are
2006 * idle, the system virtual time may be pushed-up to much
2007 * higher values than the finish timestamps of the idle
2008 * queues. As a consequence, the finish timestamps of all new
2009 * or newly activated queues may end up being much larger than
2010 * those of lucky queues with backshifted timestamps. The
2011 * latter queues may then monopolize the device for a lot of
2012 * time. This would simply break service guarantees.
2013 *
2014 * To reduce this problem, push up a little bit the
2015 * backshifted timestamps of the queue associated with this
2016 * entity (only a queue can happen to have the backshifted
2017 * flag set): just enough to let the finish timestamp of the
2018 * queue be equal to the current value of the system virtual
2019 * time. This may introduce a little unfairness among queues
2020 * with backshifted timestamps, but it does not break
2021 * worst-case fairness guarantees.
2022 *
2023 * As a special case, if bfqq is weight-raised, push up
2024 * timestamps much less, to keep very low the probability that
2025 * this push up causes the backshifted finish timestamps of
2026 * weight-raised queues to become higher than the backshifted
2027 * finish timestamps of non weight-raised queues.
2028 */
2029 if (backshifted && bfq_gt(st->vtime, entity->finish)) {
2030 unsigned long delta = st->vtime - entity->finish;
2031
2032 if (bfqq)
2033 delta /= bfqq->wr_coeff;
2034
2035 entity->start += delta;
2036 entity->finish += delta;
2037 }
2038
2039 bfq_active_insert(st, entity);
2040}
2041
2042/**
2043 * __bfq_activate_entity - handle activation of entity.
2044 * @entity: the entity being activated.
2045 * @non_blocking_wait_rq: true if entity was waiting for a request
2046 *
2047 * Called for a 'true' activation, i.e., if entity is not active and
2048 * one of its children receives a new request.
2049 *
2050 * Basically, this function updates the timestamps of entity and
2051 * inserts entity into its active tree, ater possible extracting it
2052 * from its idle tree.
2053 */
2054static void __bfq_activate_entity(struct bfq_entity *entity,
2055 bool non_blocking_wait_rq)
2056{
2057 struct bfq_service_tree *st = bfq_entity_service_tree(entity);
2058 bool backshifted = false;
2059 unsigned long long min_vstart;
2060
2061 /* See comments on bfq_fqq_update_budg_for_activation */
2062 if (non_blocking_wait_rq && bfq_gt(st->vtime, entity->finish)) {
2063 backshifted = true;
2064 min_vstart = entity->finish;
2065 } else
2066 min_vstart = st->vtime;
2067
2068 if (entity->tree == &st->idle) {
2069 /*
2070 * Must be on the idle tree, bfq_idle_extract() will
2071 * check for that.
2072 */
2073 bfq_idle_extract(st, entity);
2074 entity->start = bfq_gt(min_vstart, entity->finish) ?
2075 min_vstart : entity->finish;
2076 } else {
2077 /*
2078 * The finish time of the entity may be invalid, and
2079 * it is in the past for sure, otherwise the queue
2080 * would have been on the idle tree.
2081 */
2082 entity->start = min_vstart;
2083 st->wsum += entity->weight;
2084 /*
2085 * entity is about to be inserted into a service tree,
2086 * and then set in service: get a reference to make
2087 * sure entity does not disappear until it is no
2088 * longer in service or scheduled for service.
2089 */
2090 bfq_get_entity(entity);
2091
2092 entity->on_st = true;
2093 }
2094
2095 bfq_update_fin_time_enqueue(entity, st, backshifted);
2096}
2097
2098/**
2099 * __bfq_requeue_entity - handle requeueing or repositioning of an entity.
2100 * @entity: the entity being requeued or repositioned.
2101 *
2102 * Requeueing is needed if this entity stops being served, which
2103 * happens if a leaf descendant entity has expired. On the other hand,
2104 * repositioning is needed if the next_inservice_entity for the child
2105 * entity has changed. See the comments inside the function for
2106 * details.
2107 *
2108 * Basically, this function: 1) removes entity from its active tree if
2109 * present there, 2) updates the timestamps of entity and 3) inserts
2110 * entity back into its active tree (in the new, right position for
2111 * the new values of the timestamps).
2112 */
2113static void __bfq_requeue_entity(struct bfq_entity *entity)
2114{
2115 struct bfq_sched_data *sd = entity->sched_data;
2116 struct bfq_service_tree *st = bfq_entity_service_tree(entity);
2117
2118 if (entity == sd->in_service_entity) {
2119 /*
2120 * We are requeueing the current in-service entity,
2121 * which may have to be done for one of the following
2122 * reasons:
2123 * - entity represents the in-service queue, and the
2124 * in-service queue is being requeued after an
2125 * expiration;
2126 * - entity represents a group, and its budget has
2127 * changed because one of its child entities has
2128 * just been either activated or requeued for some
2129 * reason; the timestamps of the entity need then to
2130 * be updated, and the entity needs to be enqueued
2131 * or repositioned accordingly.
2132 *
2133 * In particular, before requeueing, the start time of
2134 * the entity must be moved forward to account for the
2135 * service that the entity has received while in
2136 * service. This is done by the next instructions. The
2137 * finish time will then be updated according to this
2138 * new value of the start time, and to the budget of
2139 * the entity.
2140 */
2141 bfq_calc_finish(entity, entity->service);
2142 entity->start = entity->finish;
2143 /*
2144 * In addition, if the entity had more than one child
2145 * when set in service, then was not extracted from
2146 * the active tree. This implies that the position of
2147 * the entity in the active tree may need to be
2148 * changed now, because we have just updated the start
2149 * time of the entity, and we will update its finish
2150 * time in a moment (the requeueing is then, more
2151 * precisely, a repositioning in this case). To
2152 * implement this repositioning, we: 1) dequeue the
2153 * entity here, 2) update the finish time and
2154 * requeue the entity according to the new
2155 * timestamps below.
2156 */
2157 if (entity->tree)
2158 bfq_active_extract(st, entity);
2159 } else { /* The entity is already active, and not in service */
2160 /*
2161 * In this case, this function gets called only if the
2162 * next_in_service entity below this entity has
2163 * changed, and this change has caused the budget of
2164 * this entity to change, which, finally implies that
2165 * the finish time of this entity must be
2166 * updated. Such an update may cause the scheduling,
2167 * i.e., the position in the active tree, of this
2168 * entity to change. We handle this change by: 1)
2169 * dequeueing the entity here, 2) updating the finish
2170 * time and requeueing the entity according to the new
2171 * timestamps below. This is the same approach as the
2172 * non-extracted-entity sub-case above.
2173 */
2174 bfq_active_extract(st, entity);
2175 }
2176
2177 bfq_update_fin_time_enqueue(entity, st, false);
2178}
2179
2180static void __bfq_activate_requeue_entity(struct bfq_entity *entity,
2181 struct bfq_sched_data *sd,
2182 bool non_blocking_wait_rq)
2183{
2184 struct bfq_service_tree *st = bfq_entity_service_tree(entity);
2185
2186 if (sd->in_service_entity == entity || entity->tree == &st->active)
2187 /*
2188 * in service or already queued on the active tree,
2189 * requeue or reposition
2190 */
2191 __bfq_requeue_entity(entity);
2192 else
2193 /*
2194 * Not in service and not queued on its active tree:
2195 * the activity is idle and this is a true activation.
2196 */
2197 __bfq_activate_entity(entity, non_blocking_wait_rq);
2198}
2199
2200
2201/**
2202 * bfq_activate_entity - activate or requeue an entity representing a bfq_queue,
2203 * and activate, requeue or reposition all ancestors
2204 * for which such an update becomes necessary.
2205 * @entity: the entity to activate.
2206 * @non_blocking_wait_rq: true if this entity was waiting for a request
2207 * @requeue: true if this is a requeue, which implies that bfqq is
2208 * being expired; thus ALL its ancestors stop being served and must
2209 * therefore be requeued
2210 */
2211static void bfq_activate_requeue_entity(struct bfq_entity *entity,
2212 bool non_blocking_wait_rq,
2213 bool requeue)
2214{
2215 struct bfq_sched_data *sd;
2216
2217 for_each_entity(entity) {
2218 sd = entity->sched_data;
2219 __bfq_activate_requeue_entity(entity, sd, non_blocking_wait_rq);
2220
2221 if (!bfq_update_next_in_service(sd, entity) && !requeue)
2222 break;
2223 }
2224}
2225
2226/**
2227 * __bfq_deactivate_entity - deactivate an entity from its service tree.
2228 * @entity: the entity to deactivate.
2229 * @ins_into_idle_tree: if false, the entity will not be put into the
2230 * idle tree.
2231 *
2232 * Deactivates an entity, independently from its previous state. Must
2233 * be invoked only if entity is on a service tree. Extracts the entity
2234 * from that tree, and if necessary and allowed, puts it on the idle
2235 * tree.
2236 */
2237static bool __bfq_deactivate_entity(struct bfq_entity *entity,
2238 bool ins_into_idle_tree)
2239{
2240 struct bfq_sched_data *sd = entity->sched_data;
2241 struct bfq_service_tree *st = bfq_entity_service_tree(entity);
2242 int is_in_service = entity == sd->in_service_entity;
2243
2244 if (!entity->on_st) /* entity never activated, or already inactive */
2245 return false;
2246
2247 if (is_in_service)
2248 bfq_calc_finish(entity, entity->service);
2249
2250 if (entity->tree == &st->active)
2251 bfq_active_extract(st, entity);
2252 else if (!is_in_service && entity->tree == &st->idle)
2253 bfq_idle_extract(st, entity);
2254
2255 if (!ins_into_idle_tree || !bfq_gt(entity->finish, st->vtime))
2256 bfq_forget_entity(st, entity, is_in_service);
2257 else
2258 bfq_idle_insert(st, entity);
2259
2260 return true;
2261}
2262
2263/**
2264 * bfq_deactivate_entity - deactivate an entity representing a bfq_queue.
2265 * @entity: the entity to deactivate.
2266 * @ins_into_idle_tree: true if the entity can be put on the idle tree
2267 */
2268static void bfq_deactivate_entity(struct bfq_entity *entity,
2269 bool ins_into_idle_tree,
2270 bool expiration)
2271{
2272 struct bfq_sched_data *sd;
2273 struct bfq_entity *parent = NULL;
2274
2275 for_each_entity_safe(entity, parent) {
2276 sd = entity->sched_data;
2277
2278 if (!__bfq_deactivate_entity(entity, ins_into_idle_tree)) {
2279 /*
2280 * entity is not in any tree any more, so
2281 * this deactivation is a no-op, and there is
2282 * nothing to change for upper-level entities
2283 * (in case of expiration, this can never
2284 * happen).
2285 */
2286 return;
2287 }
2288
2289 if (sd->next_in_service == entity)
2290 /*
2291 * entity was the next_in_service entity,
2292 * then, since entity has just been
2293 * deactivated, a new one must be found.
2294 */
2295 bfq_update_next_in_service(sd, NULL);
2296
2297 if (sd->next_in_service)
2298 /*
2299 * The parent entity is still backlogged,
2300 * because next_in_service is not NULL. So, no
2301 * further upwards deactivation must be
2302 * performed. Yet, next_in_service has
2303 * changed. Then the schedule does need to be
2304 * updated upwards.
2305 */
2306 break;
2307
2308 /*
2309 * If we get here, then the parent is no more
2310 * backlogged and we need to propagate the
2311 * deactivation upwards. Thus let the loop go on.
2312 */
2313
2314 /*
2315 * Also let parent be queued into the idle tree on
2316 * deactivation, to preserve service guarantees, and
2317 * assuming that who invoked this function does not
2318 * need parent entities too to be removed completely.
2319 */
2320 ins_into_idle_tree = true;
2321 }
2322
2323 /*
2324 * If the deactivation loop is fully executed, then there are
2325 * no more entities to touch and next loop is not executed at
2326 * all. Otherwise, requeue remaining entities if they are
2327 * about to stop receiving service, or reposition them if this
2328 * is not the case.
2329 */
2330 entity = parent;
2331 for_each_entity(entity) {
2332 /*
2333 * Invoke __bfq_requeue_entity on entity, even if
2334 * already active, to requeue/reposition it in the
2335 * active tree (because sd->next_in_service has
2336 * changed)
2337 */
2338 __bfq_requeue_entity(entity);
2339
2340 sd = entity->sched_data;
2341 if (!bfq_update_next_in_service(sd, entity) &&
2342 !expiration)
2343 /*
2344 * next_in_service unchanged or not causing
2345 * any change in entity->parent->sd, and no
2346 * requeueing needed for expiration: stop
2347 * here.
2348 */
2349 break;
2350 }
2351}
2352
2353/**
2354 * bfq_calc_vtime_jump - compute the value to which the vtime should jump,
2355 * if needed, to have at least one entity eligible.
2356 * @st: the service tree to act upon.
2357 *
2358 * Assumes that st is not empty.
2359 */
2360static u64 bfq_calc_vtime_jump(struct bfq_service_tree *st)
2361{
2362 struct bfq_entity *root_entity = bfq_root_active_entity(&st->active);
2363
2364 if (bfq_gt(root_entity->min_start, st->vtime))
2365 return root_entity->min_start;
2366
2367 return st->vtime;
2368}
2369
2370static void bfq_update_vtime(struct bfq_service_tree *st, u64 new_value)
2371{
2372 if (new_value > st->vtime) {
2373 st->vtime = new_value;
2374 bfq_forget_idle(st);
2375 }
2376}
2377
2378/**
2379 * bfq_first_active_entity - find the eligible entity with
2380 * the smallest finish time
2381 * @st: the service tree to select from.
2382 * @vtime: the system virtual to use as a reference for eligibility
2383 *
2384 * This function searches the first schedulable entity, starting from the
2385 * root of the tree and going on the left every time on this side there is
2386 * a subtree with at least one eligible (start >= vtime) entity. The path on
2387 * the right is followed only if a) the left subtree contains no eligible
2388 * entities and b) no eligible entity has been found yet.
2389 */
2390static struct bfq_entity *bfq_first_active_entity(struct bfq_service_tree *st,
2391 u64 vtime)
2392{
2393 struct bfq_entity *entry, *first = NULL;
2394 struct rb_node *node = st->active.rb_node;
2395
2396 while (node) {
2397 entry = rb_entry(node, struct bfq_entity, rb_node);
2398left:
2399 if (!bfq_gt(entry->start, vtime))
2400 first = entry;
2401
2402 if (node->rb_left) {
2403 entry = rb_entry(node->rb_left,
2404 struct bfq_entity, rb_node);
2405 if (!bfq_gt(entry->min_start, vtime)) {
2406 node = node->rb_left;
2407 goto left;
2408 }
2409 }
2410 if (first)
2411 break;
2412 node = node->rb_right;
2413 }
2414
2415 return first;
2416}
2417
2418/**
2419 * __bfq_lookup_next_entity - return the first eligible entity in @st.
2420 * @st: the service tree.
2421 *
2422 * If there is no in-service entity for the sched_data st belongs to,
2423 * then return the entity that will be set in service if:
2424 * 1) the parent entity this st belongs to is set in service;
2425 * 2) no entity belonging to such parent entity undergoes a state change
2426 * that would influence the timestamps of the entity (e.g., becomes idle,
2427 * becomes backlogged, changes its budget, ...).
2428 *
2429 * In this first case, update the virtual time in @st too (see the
2430 * comments on this update inside the function).
2431 *
2432 * In constrast, if there is an in-service entity, then return the
2433 * entity that would be set in service if not only the above
2434 * conditions, but also the next one held true: the currently
2435 * in-service entity, on expiration,
2436 * 1) gets a finish time equal to the current one, or
2437 * 2) is not eligible any more, or
2438 * 3) is idle.
2439 */
2440static struct bfq_entity *
2441__bfq_lookup_next_entity(struct bfq_service_tree *st, bool in_service)
2442{
2443 struct bfq_entity *entity;
2444 u64 new_vtime;
2445
2446 if (RB_EMPTY_ROOT(&st->active))
2447 return NULL;
2448
2449 /*
2450 * Get the value of the system virtual time for which at
2451 * least one entity is eligible.
2452 */
2453 new_vtime = bfq_calc_vtime_jump(st);
2454
2455 /*
2456 * If there is no in-service entity for the sched_data this
2457 * active tree belongs to, then push the system virtual time
2458 * up to the value that guarantees that at least one entity is
2459 * eligible. If, instead, there is an in-service entity, then
2460 * do not make any such update, because there is already an
2461 * eligible entity, namely the in-service one (even if the
2462 * entity is not on st, because it was extracted when set in
2463 * service).
2464 */
2465 if (!in_service)
2466 bfq_update_vtime(st, new_vtime);
2467
2468 entity = bfq_first_active_entity(st, new_vtime);
2469
2470 return entity;
2471}
2472
2473/**
2474 * bfq_lookup_next_entity - return the first eligible entity in @sd.
2475 * @sd: the sched_data.
2476 *
2477 * This function is invoked when there has been a change in the trees
2478 * for sd, and we need know what is the new next entity after this
2479 * change.
2480 */
2481static struct bfq_entity *bfq_lookup_next_entity(struct bfq_sched_data *sd)
2482{
2483 struct bfq_service_tree *st = sd->service_tree;
2484 struct bfq_service_tree *idle_class_st = st + (BFQ_IOPRIO_CLASSES - 1);
2485 struct bfq_entity *entity = NULL;
2486 int class_idx = 0;
2487
2488 /*
2489 * Choose from idle class, if needed to guarantee a minimum
2490 * bandwidth to this class (and if there is some active entity
2491 * in idle class). This should also mitigate
2492 * priority-inversion problems in case a low priority task is
2493 * holding file system resources.
2494 */
2495 if (time_is_before_jiffies(sd->bfq_class_idle_last_service +
2496 BFQ_CL_IDLE_TIMEOUT)) {
2497 if (!RB_EMPTY_ROOT(&idle_class_st->active))
2498 class_idx = BFQ_IOPRIO_CLASSES - 1;
2499 /* About to be served if backlogged, or not yet backlogged */
2500 sd->bfq_class_idle_last_service = jiffies;
2501 }
2502
2503 /*
2504 * Find the next entity to serve for the highest-priority
2505 * class, unless the idle class needs to be served.
2506 */
2507 for (; class_idx < BFQ_IOPRIO_CLASSES; class_idx++) {
2508 entity = __bfq_lookup_next_entity(st + class_idx,
2509 sd->in_service_entity);
2510
2511 if (entity)
2512 break;
2513 }
2514
2515 if (!entity)
2516 return NULL;
2517
2518 return entity;
2519}
2520
2521static bool next_queue_may_preempt(struct bfq_data *bfqd)
2522{
2523 struct bfq_sched_data *sd = &bfqd->root_group->sched_data;
2524
2525 return sd->next_in_service != sd->in_service_entity;
2526}
2527
2528/*
2529 * Get next queue for service.
2530 */
2531static struct bfq_queue *bfq_get_next_queue(struct bfq_data *bfqd)
2532{
2533 struct bfq_entity *entity = NULL;
2534 struct bfq_sched_data *sd;
2535 struct bfq_queue *bfqq;
2536
2537 if (bfqd->busy_queues == 0)
2538 return NULL;
2539
2540 /*
2541 * Traverse the path from the root to the leaf entity to
2542 * serve. Set in service all the entities visited along the
2543 * way.
2544 */
2545 sd = &bfqd->root_group->sched_data;
2546 for (; sd ; sd = entity->my_sched_data) {
2547 /*
2548 * WARNING. We are about to set the in-service entity
2549 * to sd->next_in_service, i.e., to the (cached) value
2550 * returned by bfq_lookup_next_entity(sd) the last
2551 * time it was invoked, i.e., the last time when the
2552 * service order in sd changed as a consequence of the
2553 * activation or deactivation of an entity. In this
2554 * respect, if we execute bfq_lookup_next_entity(sd)
2555 * in this very moment, it may, although with low
2556 * probability, yield a different entity than that
2557 * pointed to by sd->next_in_service. This rare event
2558 * happens in case there was no CLASS_IDLE entity to
2559 * serve for sd when bfq_lookup_next_entity(sd) was
2560 * invoked for the last time, while there is now one
2561 * such entity.
2562 *
2563 * If the above event happens, then the scheduling of
2564 * such entity in CLASS_IDLE is postponed until the
2565 * service of the sd->next_in_service entity
2566 * finishes. In fact, when the latter is expired,
2567 * bfq_lookup_next_entity(sd) gets called again,
2568 * exactly to update sd->next_in_service.
2569 */
2570
2571 /* Make next_in_service entity become in_service_entity */
2572 entity = sd->next_in_service;
2573 sd->in_service_entity = entity;
2574
2575 /*
2576 * Reset the accumulator of the amount of service that
2577 * the entity is about to receive.
2578 */
2579 entity->service = 0;
2580
2581 /*
2582 * If entity is no longer a candidate for next
2583 * service, then we extract it from its active tree,
2584 * for the following reason. To further boost the
2585 * throughput in some special case, BFQ needs to know
2586 * which is the next candidate entity to serve, while
2587 * there is already an entity in service. In this
2588 * respect, to make it easy to compute/update the next
2589 * candidate entity to serve after the current
2590 * candidate has been set in service, there is a case
2591 * where it is necessary to extract the current
2592 * candidate from its service tree. Such a case is
2593 * when the entity just set in service cannot be also
2594 * a candidate for next service. Details about when
2595 * this conditions holds are reported in the comments
2596 * on the function bfq_no_longer_next_in_service()
2597 * invoked below.
2598 */
2599 if (bfq_no_longer_next_in_service(entity))
2600 bfq_active_extract(bfq_entity_service_tree(entity),
2601 entity);
2602
2603 /*
2604 * For the same reason why we may have just extracted
2605 * entity from its active tree, we may need to update
2606 * next_in_service for the sched_data of entity too,
2607 * regardless of whether entity has been extracted.
2608 * In fact, even if entity has not been extracted, a
2609 * descendant entity may get extracted. Such an event
2610 * would cause a change in next_in_service for the
2611 * level of the descendant entity, and thus possibly
2612 * back to upper levels.
2613 *
2614 * We cannot perform the resulting needed update
2615 * before the end of this loop, because, to know which
2616 * is the correct next-to-serve candidate entity for
2617 * each level, we need first to find the leaf entity
2618 * to set in service. In fact, only after we know
2619 * which is the next-to-serve leaf entity, we can
2620 * discover whether the parent entity of the leaf
2621 * entity becomes the next-to-serve, and so on.
2622 */
2623
2624 }
2625
2626 bfqq = bfq_entity_to_bfqq(entity);
2627
2628 /*
2629 * We can finally update all next-to-serve entities along the
2630 * path from the leaf entity just set in service to the root.
2631 */
2632 for_each_entity(entity) {
2633 struct bfq_sched_data *sd = entity->sched_data;
2634
2635 if (!bfq_update_next_in_service(sd, NULL))
2636 break;
2637 }
2638
2639 return bfqq;
2640}
2641
2642static void __bfq_bfqd_reset_in_service(struct bfq_data *bfqd)
2643{
2644 struct bfq_queue *in_serv_bfqq = bfqd->in_service_queue;
2645 struct bfq_entity *in_serv_entity = &in_serv_bfqq->entity;
2646 struct bfq_entity *entity = in_serv_entity;
2647
2648 bfq_clear_bfqq_wait_request(in_serv_bfqq);
2649 hrtimer_try_to_cancel(&bfqd->idle_slice_timer);
2650 bfqd->in_service_queue = NULL;
2651
2652 /*
2653 * When this function is called, all in-service entities have
2654 * been properly deactivated or requeued, so we can safely
2655 * execute the final step: reset in_service_entity along the
2656 * path from entity to the root.
2657 */
2658 for_each_entity(entity)
2659 entity->sched_data->in_service_entity = NULL;
2660
2661 /*
2662 * in_serv_entity is no longer in service, so, if it is in no
2663 * service tree either, then release the service reference to
2664 * the queue it represents (taken with bfq_get_entity).
2665 */
2666 if (!in_serv_entity->on_st)
2667 bfq_put_queue(in_serv_bfqq);
2668}
2669
2670static void bfq_deactivate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq,
2671 bool ins_into_idle_tree, bool expiration)
2672{
2673 struct bfq_entity *entity = &bfqq->entity;
2674
2675 bfq_deactivate_entity(entity, ins_into_idle_tree, expiration);
2676}
2677
2678static void bfq_activate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq)
2679{
2680 struct bfq_entity *entity = &bfqq->entity;
2681
2682 bfq_activate_requeue_entity(entity, bfq_bfqq_non_blocking_wait_rq(bfqq),
2683 false);
2684 bfq_clear_bfqq_non_blocking_wait_rq(bfqq);
2685}
2686
2687static void bfq_requeue_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq)
2688{
2689 struct bfq_entity *entity = &bfqq->entity;
2690
2691 bfq_activate_requeue_entity(entity, false,
2692 bfqq == bfqd->in_service_queue);
2693}
2694
2695static void bfqg_stats_update_dequeue(struct bfq_group *bfqg);
2696
2697/*
2698 * Called when the bfqq no longer has requests pending, remove it from
2699 * the service tree. As a special case, it can be invoked during an
2700 * expiration.
2701 */
2702static void bfq_del_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq,
2703 bool expiration)
2704{
2705 bfq_log_bfqq(bfqd, bfqq, "del from busy");
2706
2707 bfq_clear_bfqq_busy(bfqq);
2708
2709 bfqd->busy_queues--;
2710
2711 if (!bfqq->dispatched)
2712 bfq_weights_tree_remove(bfqd, &bfqq->entity,
2713 &bfqd->queue_weights_tree);
2714
2715 if (bfqq->wr_coeff > 1)
2716 bfqd->wr_busy_queues--;
2717
2718 bfqg_stats_update_dequeue(bfqq_group(bfqq));
2719
2720 bfq_deactivate_bfqq(bfqd, bfqq, true, expiration);
2721}
2722
2723/*
2724 * Called when an inactive queue receives a new request.
2725 */
2726static void bfq_add_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq)
2727{
2728 bfq_log_bfqq(bfqd, bfqq, "add to busy");
2729
2730 bfq_activate_bfqq(bfqd, bfqq);
2731
2732 bfq_mark_bfqq_busy(bfqq);
2733 bfqd->busy_queues++;
2734
2735 if (!bfqq->dispatched)
2736 if (bfqq->wr_coeff == 1)
2737 bfq_weights_tree_add(bfqd, &bfqq->entity,
2738 &bfqd->queue_weights_tree);
2739
2740 if (bfqq->wr_coeff > 1)
2741 bfqd->wr_busy_queues++;
2742}
2743
2744#ifdef CONFIG_BFQ_GROUP_IOSCHED
2745
2746/* bfqg stats flags */
2747enum bfqg_stats_flags {
2748 BFQG_stats_waiting = 0,
2749 BFQG_stats_idling,
2750 BFQG_stats_empty,
2751};
2752
2753#define BFQG_FLAG_FNS(name) \
2754static void bfqg_stats_mark_##name(struct bfqg_stats *stats) \
2755{ \
2756 stats->flags |= (1 << BFQG_stats_##name); \
2757} \
2758static void bfqg_stats_clear_##name(struct bfqg_stats *stats) \
2759{ \
2760 stats->flags &= ~(1 << BFQG_stats_##name); \
2761} \
2762static int bfqg_stats_##name(struct bfqg_stats *stats) \
2763{ \
2764 return (stats->flags & (1 << BFQG_stats_##name)) != 0; \
2765} \
2766
2767BFQG_FLAG_FNS(waiting)
2768BFQG_FLAG_FNS(idling)
2769BFQG_FLAG_FNS(empty)
2770#undef BFQG_FLAG_FNS
2771
2772/* This should be called with the queue_lock held. */
2773static void bfqg_stats_update_group_wait_time(struct bfqg_stats *stats)
2774{
2775 unsigned long long now;
2776
2777 if (!bfqg_stats_waiting(stats))
2778 return;
2779
2780 now = sched_clock();
2781 if (time_after64(now, stats->start_group_wait_time))
2782 blkg_stat_add(&stats->group_wait_time,
2783 now - stats->start_group_wait_time);
2784 bfqg_stats_clear_waiting(stats);
2785}
2786
2787/* This should be called with the queue_lock held. */
2788static void bfqg_stats_set_start_group_wait_time(struct bfq_group *bfqg,
2789 struct bfq_group *curr_bfqg)
2790{
2791 struct bfqg_stats *stats = &bfqg->stats;
2792
2793 if (bfqg_stats_waiting(stats))
2794 return;
2795 if (bfqg == curr_bfqg)
2796 return;
2797 stats->start_group_wait_time = sched_clock();
2798 bfqg_stats_mark_waiting(stats);
2799}
2800
2801/* This should be called with the queue_lock held. */
2802static void bfqg_stats_end_empty_time(struct bfqg_stats *stats)
2803{
2804 unsigned long long now;
2805
2806 if (!bfqg_stats_empty(stats))
2807 return;
2808
2809 now = sched_clock();
2810 if (time_after64(now, stats->start_empty_time))
2811 blkg_stat_add(&stats->empty_time,
2812 now - stats->start_empty_time);
2813 bfqg_stats_clear_empty(stats);
2814}
2815
2816static void bfqg_stats_update_dequeue(struct bfq_group *bfqg)
2817{
2818 blkg_stat_add(&bfqg->stats.dequeue, 1);
2819}
2820
2821static void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg)
2822{
2823 struct bfqg_stats *stats = &bfqg->stats;
2824
2825 if (blkg_rwstat_total(&stats->queued))
2826 return;
2827
2828 /*
2829 * group is already marked empty. This can happen if bfqq got new
2830 * request in parent group and moved to this group while being added
2831 * to service tree. Just ignore the event and move on.
2832 */
2833 if (bfqg_stats_empty(stats))
2834 return;
2835
2836 stats->start_empty_time = sched_clock();
2837 bfqg_stats_mark_empty(stats);
2838}
2839
2840static void bfqg_stats_update_idle_time(struct bfq_group *bfqg)
2841{
2842 struct bfqg_stats *stats = &bfqg->stats;
2843
2844 if (bfqg_stats_idling(stats)) {
2845 unsigned long long now = sched_clock();
2846
2847 if (time_after64(now, stats->start_idle_time))
2848 blkg_stat_add(&stats->idle_time,
2849 now - stats->start_idle_time);
2850 bfqg_stats_clear_idling(stats);
2851 }
2852}
2853
2854static void bfqg_stats_set_start_idle_time(struct bfq_group *bfqg)
2855{
2856 struct bfqg_stats *stats = &bfqg->stats;
2857
2858 stats->start_idle_time = sched_clock();
2859 bfqg_stats_mark_idling(stats);
2860}
2861
2862static void bfqg_stats_update_avg_queue_size(struct bfq_group *bfqg)
2863{
2864 struct bfqg_stats *stats = &bfqg->stats;
2865
2866 blkg_stat_add(&stats->avg_queue_size_sum,
2867 blkg_rwstat_total(&stats->queued));
2868 blkg_stat_add(&stats->avg_queue_size_samples, 1);
2869 bfqg_stats_update_group_wait_time(stats);
2870}
2871
2872/*
2873 * blk-cgroup policy-related handlers
2874 * The following functions help in converting between blk-cgroup
2875 * internal structures and BFQ-specific structures.
2876 */
2877
2878static struct bfq_group *pd_to_bfqg(struct blkg_policy_data *pd)
2879{
2880 return pd ? container_of(pd, struct bfq_group, pd) : NULL;
2881}
2882
2883static struct blkcg_gq *bfqg_to_blkg(struct bfq_group *bfqg)
2884{
2885 return pd_to_blkg(&bfqg->pd);
2886}
2887
2888static struct blkcg_policy blkcg_policy_bfq;
2889
2890static struct bfq_group *blkg_to_bfqg(struct blkcg_gq *blkg)
2891{
2892 return pd_to_bfqg(blkg_to_pd(blkg, &blkcg_policy_bfq));
2893}
2894
2895/*
2896 * bfq_group handlers
2897 * The following functions help in navigating the bfq_group hierarchy
2898 * by allowing to find the parent of a bfq_group or the bfq_group
2899 * associated to a bfq_queue.
2900 */
2901
2902static struct bfq_group *bfqg_parent(struct bfq_group *bfqg)
2903{
2904 struct blkcg_gq *pblkg = bfqg_to_blkg(bfqg)->parent;
2905
2906 return pblkg ? blkg_to_bfqg(pblkg) : NULL;
2907}
2908
2909static struct bfq_group *bfqq_group(struct bfq_queue *bfqq)
2910{
2911 struct bfq_entity *group_entity = bfqq->entity.parent;
2912
2913 return group_entity ? container_of(group_entity, struct bfq_group,
2914 entity) :
2915 bfqq->bfqd->root_group;
2916}
2917
2918/*
2919 * The following two functions handle get and put of a bfq_group by
2920 * wrapping the related blk-cgroup hooks.
2921 */
2922
2923static void bfqg_get(struct bfq_group *bfqg)
2924{
2925 return blkg_get(bfqg_to_blkg(bfqg));
2926}
2927
2928static void bfqg_put(struct bfq_group *bfqg)
2929{
2930 return blkg_put(bfqg_to_blkg(bfqg));
2931}
2932
2933static void bfqg_stats_update_io_add(struct bfq_group *bfqg,
2934 struct bfq_queue *bfqq,
2935 unsigned int op)
2936{
2937 blkg_rwstat_add(&bfqg->stats.queued, op, 1);
2938 bfqg_stats_end_empty_time(&bfqg->stats);
2939 if (!(bfqq == ((struct bfq_data *)bfqg->bfqd)->in_service_queue))
2940 bfqg_stats_set_start_group_wait_time(bfqg, bfqq_group(bfqq));
2941}
2942
2943static void bfqg_stats_update_io_remove(struct bfq_group *bfqg, unsigned int op)
2944{
2945 blkg_rwstat_add(&bfqg->stats.queued, op, -1);
2946}
2947
2948static void bfqg_stats_update_io_merged(struct bfq_group *bfqg, unsigned int op)
2949{
2950 blkg_rwstat_add(&bfqg->stats.merged, op, 1);
2951}
2952
2953static void bfqg_stats_update_completion(struct bfq_group *bfqg,
2954 uint64_t start_time, uint64_t io_start_time,
2955 unsigned int op)
2956{
2957 struct bfqg_stats *stats = &bfqg->stats;
2958 unsigned long long now = sched_clock();
2959
2960 if (time_after64(now, io_start_time))
2961 blkg_rwstat_add(&stats->service_time, op,
2962 now - io_start_time);
2963 if (time_after64(io_start_time, start_time))
2964 blkg_rwstat_add(&stats->wait_time, op,
2965 io_start_time - start_time);
2966}
2967
2968/* @stats = 0 */
2969static void bfqg_stats_reset(struct bfqg_stats *stats)
2970{
2971 /* queued stats shouldn't be cleared */
2972 blkg_rwstat_reset(&stats->merged);
2973 blkg_rwstat_reset(&stats->service_time);
2974 blkg_rwstat_reset(&stats->wait_time);
2975 blkg_stat_reset(&stats->time);
2976 blkg_stat_reset(&stats->avg_queue_size_sum);
2977 blkg_stat_reset(&stats->avg_queue_size_samples);
2978 blkg_stat_reset(&stats->dequeue);
2979 blkg_stat_reset(&stats->group_wait_time);
2980 blkg_stat_reset(&stats->idle_time);
2981 blkg_stat_reset(&stats->empty_time);
2982}
2983
2984/* @to += @from */
2985static void bfqg_stats_add_aux(struct bfqg_stats *to, struct bfqg_stats *from)
2986{
2987 if (!to || !from)
2988 return;
2989
2990 /* queued stats shouldn't be cleared */
2991 blkg_rwstat_add_aux(&to->merged, &from->merged);
2992 blkg_rwstat_add_aux(&to->service_time, &from->service_time);
2993 blkg_rwstat_add_aux(&to->wait_time, &from->wait_time);
2994 blkg_stat_add_aux(&from->time, &from->time);
2995 blkg_stat_add_aux(&to->avg_queue_size_sum, &from->avg_queue_size_sum);
2996 blkg_stat_add_aux(&to->avg_queue_size_samples,
2997 &from->avg_queue_size_samples);
2998 blkg_stat_add_aux(&to->dequeue, &from->dequeue);
2999 blkg_stat_add_aux(&to->group_wait_time, &from->group_wait_time);
3000 blkg_stat_add_aux(&to->idle_time, &from->idle_time);
3001 blkg_stat_add_aux(&to->empty_time, &from->empty_time);
3002}
3003
3004/*
3005 * Transfer @bfqg's stats to its parent's aux counts so that the ancestors'
3006 * recursive stats can still account for the amount used by this bfqg after
3007 * it's gone.
3008 */
3009static void bfqg_stats_xfer_dead(struct bfq_group *bfqg)
3010{
3011 struct bfq_group *parent;
3012
3013 if (!bfqg) /* root_group */
3014 return;
3015
3016 parent = bfqg_parent(bfqg);
3017
3018 lockdep_assert_held(bfqg_to_blkg(bfqg)->q->queue_lock);
3019
3020 if (unlikely(!parent))
3021 return;
3022
3023 bfqg_stats_add_aux(&parent->stats, &bfqg->stats);
3024 bfqg_stats_reset(&bfqg->stats);
3025}
3026
3027static void bfq_init_entity(struct bfq_entity *entity,
3028 struct bfq_group *bfqg)
3029{
3030 struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity);
3031
3032 entity->weight = entity->new_weight;
3033 entity->orig_weight = entity->new_weight;
3034 if (bfqq) {
3035 bfqq->ioprio = bfqq->new_ioprio;
3036 bfqq->ioprio_class = bfqq->new_ioprio_class;
3037 bfqg_get(bfqg);
3038 }
3039 entity->parent = bfqg->my_entity; /* NULL for root group */
3040 entity->sched_data = &bfqg->sched_data;
3041}
3042
3043static void bfqg_stats_exit(struct bfqg_stats *stats)
3044{
3045 blkg_rwstat_exit(&stats->merged);
3046 blkg_rwstat_exit(&stats->service_time);
3047 blkg_rwstat_exit(&stats->wait_time);
3048 blkg_rwstat_exit(&stats->queued);
3049 blkg_stat_exit(&stats->time);
3050 blkg_stat_exit(&stats->avg_queue_size_sum);
3051 blkg_stat_exit(&stats->avg_queue_size_samples);
3052 blkg_stat_exit(&stats->dequeue);
3053 blkg_stat_exit(&stats->group_wait_time);
3054 blkg_stat_exit(&stats->idle_time);
3055 blkg_stat_exit(&stats->empty_time);
3056}
3057
3058static int bfqg_stats_init(struct bfqg_stats *stats, gfp_t gfp)
3059{
3060 if (blkg_rwstat_init(&stats->merged, gfp) ||
3061 blkg_rwstat_init(&stats->service_time, gfp) ||
3062 blkg_rwstat_init(&stats->wait_time, gfp) ||
3063 blkg_rwstat_init(&stats->queued, gfp) ||
3064 blkg_stat_init(&stats->time, gfp) ||
3065 blkg_stat_init(&stats->avg_queue_size_sum, gfp) ||
3066 blkg_stat_init(&stats->avg_queue_size_samples, gfp) ||
3067 blkg_stat_init(&stats->dequeue, gfp) ||
3068 blkg_stat_init(&stats->group_wait_time, gfp) ||
3069 blkg_stat_init(&stats->idle_time, gfp) ||
3070 blkg_stat_init(&stats->empty_time, gfp)) {
3071 bfqg_stats_exit(stats);
3072 return -ENOMEM;
3073 }
3074
3075 return 0;
3076}
3077
3078static struct bfq_group_data *cpd_to_bfqgd(struct blkcg_policy_data *cpd)
3079{
3080 return cpd ? container_of(cpd, struct bfq_group_data, pd) : NULL;
3081}
3082
3083static struct bfq_group_data *blkcg_to_bfqgd(struct blkcg *blkcg)
3084{
3085 return cpd_to_bfqgd(blkcg_to_cpd(blkcg, &blkcg_policy_bfq));
3086}
3087
3088static struct blkcg_policy_data *bfq_cpd_alloc(gfp_t gfp)
3089{
3090 struct bfq_group_data *bgd;
3091
3092 bgd = kzalloc(sizeof(*bgd), gfp);
3093 if (!bgd)
3094 return NULL;
3095 return &bgd->pd;
3096}
3097
3098static void bfq_cpd_init(struct blkcg_policy_data *cpd)
3099{
3100 struct bfq_group_data *d = cpd_to_bfqgd(cpd);
3101
3102 d->weight = cgroup_subsys_on_dfl(io_cgrp_subsys) ?
3103 CGROUP_WEIGHT_DFL : BFQ_WEIGHT_LEGACY_DFL;
3104}
3105
3106static void bfq_cpd_free(struct blkcg_policy_data *cpd)
3107{
3108 kfree(cpd_to_bfqgd(cpd));
3109}
3110
3111static struct blkg_policy_data *bfq_pd_alloc(gfp_t gfp, int node)
3112{
3113 struct bfq_group *bfqg;
3114
3115 bfqg = kzalloc_node(sizeof(*bfqg), gfp, node);
3116 if (!bfqg)
3117 return NULL;
3118
3119 if (bfqg_stats_init(&bfqg->stats, gfp)) {
3120 kfree(bfqg);
3121 return NULL;
3122 }
3123
3124 return &bfqg->pd;
3125}
3126
3127static void bfq_pd_init(struct blkg_policy_data *pd)
3128{
3129 struct blkcg_gq *blkg = pd_to_blkg(pd);
3130 struct bfq_group *bfqg = blkg_to_bfqg(blkg);
3131 struct bfq_data *bfqd = blkg->q->elevator->elevator_data;
3132 struct bfq_entity *entity = &bfqg->entity;
3133 struct bfq_group_data *d = blkcg_to_bfqgd(blkg->blkcg);
3134
3135 entity->orig_weight = entity->weight = entity->new_weight = d->weight;
3136 entity->my_sched_data = &bfqg->sched_data;
3137 bfqg->my_entity = entity; /*
3138 * the root_group's will be set to NULL
3139 * in bfq_init_queue()
3140 */
3141 bfqg->bfqd = bfqd;
3142 bfqg->active_entities = 0;
3143 bfqg->rq_pos_tree = RB_ROOT;
3144}
3145
3146static void bfq_pd_free(struct blkg_policy_data *pd)
3147{
3148 struct bfq_group *bfqg = pd_to_bfqg(pd);
3149
3150 bfqg_stats_exit(&bfqg->stats);
3151 return kfree(bfqg);
3152}
3153
3154static void bfq_pd_reset_stats(struct blkg_policy_data *pd)
3155{
3156 struct bfq_group *bfqg = pd_to_bfqg(pd);
3157
3158 bfqg_stats_reset(&bfqg->stats);
3159}
3160
3161static void bfq_group_set_parent(struct bfq_group *bfqg,
3162 struct bfq_group *parent)
3163{
3164 struct bfq_entity *entity;
3165
3166 entity = &bfqg->entity;
3167 entity->parent = parent->my_entity;
3168 entity->sched_data = &parent->sched_data;
3169}
3170
3171static struct bfq_group *bfq_lookup_bfqg(struct bfq_data *bfqd,
3172 struct blkcg *blkcg)
3173{
3174 struct blkcg_gq *blkg;
3175
3176 blkg = blkg_lookup(blkcg, bfqd->queue);
3177 if (likely(blkg))
3178 return blkg_to_bfqg(blkg);
3179 return NULL;
3180}
3181
3182static struct bfq_group *bfq_find_set_group(struct bfq_data *bfqd,
3183 struct blkcg *blkcg)
3184{
3185 struct bfq_group *bfqg, *parent;
3186 struct bfq_entity *entity;
3187
3188 bfqg = bfq_lookup_bfqg(bfqd, blkcg);
3189
3190 if (unlikely(!bfqg))
3191 return NULL;
3192
3193 /*
3194 * Update chain of bfq_groups as we might be handling a leaf group
3195 * which, along with some of its relatives, has not been hooked yet
3196 * to the private hierarchy of BFQ.
3197 */
3198 entity = &bfqg->entity;
3199 for_each_entity(entity) {
3200 bfqg = container_of(entity, struct bfq_group, entity);
3201 if (bfqg != bfqd->root_group) {
3202 parent = bfqg_parent(bfqg);
3203 if (!parent)
3204 parent = bfqd->root_group;
3205 bfq_group_set_parent(bfqg, parent);
3206 }
3207 }
3208
3209 return bfqg;
3210}
3211
3212static void bfq_pos_tree_add_move(struct bfq_data *bfqd,
3213 struct bfq_queue *bfqq);
3214static void bfq_bfqq_expire(struct bfq_data *bfqd,
3215 struct bfq_queue *bfqq,
3216 bool compensate,
3217 enum bfqq_expiration reason);
3218
3219/**
3220 * bfq_bfqq_move - migrate @bfqq to @bfqg.
3221 * @bfqd: queue descriptor.
3222 * @bfqq: the queue to move.
3223 * @bfqg: the group to move to.
3224 *
3225 * Move @bfqq to @bfqg, deactivating it from its old group and reactivating
3226 * it on the new one. Avoid putting the entity on the old group idle tree.
3227 *
3228 * Must be called under the queue lock; the cgroup owning @bfqg must
3229 * not disappear (by now this just means that we are called under
3230 * rcu_read_lock()).
3231 */
3232static void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq,
3233 struct bfq_group *bfqg)
3234{
3235 struct bfq_entity *entity = &bfqq->entity;
3236
3237 /* If bfqq is empty, then bfq_bfqq_expire also invokes
3238 * bfq_del_bfqq_busy, thereby removing bfqq and its entity
3239 * from data structures related to current group. Otherwise we
3240 * need to remove bfqq explicitly with bfq_deactivate_bfqq, as
3241 * we do below.
3242 */
3243 if (bfqq == bfqd->in_service_queue)
3244 bfq_bfqq_expire(bfqd, bfqd->in_service_queue,
3245 false, BFQQE_PREEMPTED);
3246
3247 if (bfq_bfqq_busy(bfqq))
3248 bfq_deactivate_bfqq(bfqd, bfqq, false, false);
3249 else if (entity->on_st)
3250 bfq_put_idle_entity(bfq_entity_service_tree(entity), entity);
3251 bfqg_put(bfqq_group(bfqq));
3252
3253 /*
3254 * Here we use a reference to bfqg. We don't need a refcounter
3255 * as the cgroup reference will not be dropped, so that its
3256 * destroy() callback will not be invoked.
3257 */
3258 entity->parent = bfqg->my_entity;
3259 entity->sched_data = &bfqg->sched_data;
3260 bfqg_get(bfqg);
3261
3262 if (bfq_bfqq_busy(bfqq)) {
3263 bfq_pos_tree_add_move(bfqd, bfqq);
3264 bfq_activate_bfqq(bfqd, bfqq);
3265 }
3266
3267 if (!bfqd->in_service_queue && !bfqd->rq_in_driver)
3268 bfq_schedule_dispatch(bfqd);
3269}
3270
3271/**
3272 * __bfq_bic_change_cgroup - move @bic to @cgroup.
3273 * @bfqd: the queue descriptor.
3274 * @bic: the bic to move.
3275 * @blkcg: the blk-cgroup to move to.
3276 *
3277 * Move bic to blkcg, assuming that bfqd->queue is locked; the caller
3278 * has to make sure that the reference to cgroup is valid across the call.
3279 *
3280 * NOTE: an alternative approach might have been to store the current
3281 * cgroup in bfqq and getting a reference to it, reducing the lookup
3282 * time here, at the price of slightly more complex code.
3283 */
3284static struct bfq_group *__bfq_bic_change_cgroup(struct bfq_data *bfqd,
3285 struct bfq_io_cq *bic,
3286 struct blkcg *blkcg)
3287{
3288 struct bfq_queue *async_bfqq = bic_to_bfqq(bic, 0);
3289 struct bfq_queue *sync_bfqq = bic_to_bfqq(bic, 1);
3290 struct bfq_group *bfqg;
3291 struct bfq_entity *entity;
3292
3293 bfqg = bfq_find_set_group(bfqd, blkcg);
3294
3295 if (unlikely(!bfqg))
3296 bfqg = bfqd->root_group;
3297
3298 if (async_bfqq) {
3299 entity = &async_bfqq->entity;
3300
3301 if (entity->sched_data != &bfqg->sched_data) {
3302 bic_set_bfqq(bic, NULL, 0);
3303 bfq_log_bfqq(bfqd, async_bfqq,
3304 "bic_change_group: %p %d",
3305 async_bfqq, async_bfqq->ref);
3306 bfq_put_queue(async_bfqq);
3307 }
3308 }
3309
3310 if (sync_bfqq) {
3311 entity = &sync_bfqq->entity;
3312 if (entity->sched_data != &bfqg->sched_data)
3313 bfq_bfqq_move(bfqd, sync_bfqq, bfqg);
3314 }
3315
3316 return bfqg;
3317}
3318
3319static void bfq_bic_update_cgroup(struct bfq_io_cq *bic, struct bio *bio)
3320{
3321 struct bfq_data *bfqd = bic_to_bfqd(bic);
3322 struct bfq_group *bfqg = NULL;
3323 uint64_t serial_nr;
3324
3325 rcu_read_lock();
3326 serial_nr = bio_blkcg(bio)->css.serial_nr;
3327
3328 /*
3329 * Check whether blkcg has changed. The condition may trigger
3330 * spuriously on a newly created cic but there's no harm.
3331 */
3332 if (unlikely(!bfqd) || likely(bic->blkcg_serial_nr == serial_nr))
3333 goto out;
3334
3335 bfqg = __bfq_bic_change_cgroup(bfqd, bic, bio_blkcg(bio));
3336 bic->blkcg_serial_nr = serial_nr;
3337out:
3338 rcu_read_unlock();
3339}
3340
3341/**
3342 * bfq_flush_idle_tree - deactivate any entity on the idle tree of @st.
3343 * @st: the service tree being flushed.
3344 */
3345static void bfq_flush_idle_tree(struct bfq_service_tree *st)
3346{
3347 struct bfq_entity *entity = st->first_idle;
3348
3349 for (; entity ; entity = st->first_idle)
3350 __bfq_deactivate_entity(entity, false);
3351}
3352
3353/**
3354 * bfq_reparent_leaf_entity - move leaf entity to the root_group.
3355 * @bfqd: the device data structure with the root group.
3356 * @entity: the entity to move.
3357 */
3358static void bfq_reparent_leaf_entity(struct bfq_data *bfqd,
3359 struct bfq_entity *entity)
3360{
3361 struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity);
3362
3363 bfq_bfqq_move(bfqd, bfqq, bfqd->root_group);
3364}
3365
3366/**
3367 * bfq_reparent_active_entities - move to the root group all active
3368 * entities.
3369 * @bfqd: the device data structure with the root group.
3370 * @bfqg: the group to move from.
3371 * @st: the service tree with the entities.
3372 *
3373 * Needs queue_lock to be taken and reference to be valid over the call.
3374 */
3375static void bfq_reparent_active_entities(struct bfq_data *bfqd,
3376 struct bfq_group *bfqg,
3377 struct bfq_service_tree *st)
3378{
3379 struct rb_root *active = &st->active;
3380 struct bfq_entity *entity = NULL;
3381
3382 if (!RB_EMPTY_ROOT(&st->active))
3383 entity = bfq_entity_of(rb_first(active));
3384
3385 for (; entity ; entity = bfq_entity_of(rb_first(active)))
3386 bfq_reparent_leaf_entity(bfqd, entity);
3387
3388 if (bfqg->sched_data.in_service_entity)
3389 bfq_reparent_leaf_entity(bfqd,
3390 bfqg->sched_data.in_service_entity);
3391}
3392
3393/**
3394 * bfq_pd_offline - deactivate the entity associated with @pd,
3395 * and reparent its children entities.
3396 * @pd: descriptor of the policy going offline.
3397 *
3398 * blkio already grabs the queue_lock for us, so no need to use
3399 * RCU-based magic
3400 */
3401static void bfq_pd_offline(struct blkg_policy_data *pd)
3402{
3403 struct bfq_service_tree *st;
3404 struct bfq_group *bfqg = pd_to_bfqg(pd);
3405 struct bfq_data *bfqd = bfqg->bfqd;
3406 struct bfq_entity *entity = bfqg->my_entity;
3407 unsigned long flags;
3408 int i;
3409
3410 if (!entity) /* root group */
3411 return;
3412
3413 spin_lock_irqsave(&bfqd->lock, flags);
3414 /*
3415 * Empty all service_trees belonging to this group before
3416 * deactivating the group itself.
3417 */
3418 for (i = 0; i < BFQ_IOPRIO_CLASSES; i++) {
3419 st = bfqg->sched_data.service_tree + i;
3420
3421 /*
3422 * The idle tree may still contain bfq_queues belonging
3423 * to exited task because they never migrated to a different
3424 * cgroup from the one being destroyed now. No one else
3425 * can access them so it's safe to act without any lock.
3426 */
3427 bfq_flush_idle_tree(st);
3428
3429 /*
3430 * It may happen that some queues are still active
3431 * (busy) upon group destruction (if the corresponding
3432 * processes have been forced to terminate). We move
3433 * all the leaf entities corresponding to these queues
3434 * to the root_group.
3435 * Also, it may happen that the group has an entity
3436 * in service, which is disconnected from the active
3437 * tree: it must be moved, too.
3438 * There is no need to put the sync queues, as the
3439 * scheduler has taken no reference.
3440 */
3441 bfq_reparent_active_entities(bfqd, bfqg, st);
3442 }
3443
3444 __bfq_deactivate_entity(entity, false);
3445 bfq_put_async_queues(bfqd, bfqg);
3446
3447 spin_unlock_irqrestore(&bfqd->lock, flags);
3448 /*
3449 * @blkg is going offline and will be ignored by
3450 * blkg_[rw]stat_recursive_sum(). Transfer stats to the parent so
3451 * that they don't get lost. If IOs complete after this point, the
3452 * stats for them will be lost. Oh well...
3453 */
3454 bfqg_stats_xfer_dead(bfqg);
3455}
3456
3457static void bfq_end_wr_async(struct bfq_data *bfqd)
3458{
3459 struct blkcg_gq *blkg;
3460
3461 list_for_each_entry(blkg, &bfqd->queue->blkg_list, q_node) {
3462 struct bfq_group *bfqg = blkg_to_bfqg(blkg);
3463
3464 bfq_end_wr_async_queues(bfqd, bfqg);
3465 }
3466 bfq_end_wr_async_queues(bfqd, bfqd->root_group);
3467}
3468
3469static int bfq_io_show_weight(struct seq_file *sf, void *v)
3470{
3471 struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
3472 struct bfq_group_data *bfqgd = blkcg_to_bfqgd(blkcg);
3473 unsigned int val = 0;
3474
3475 if (bfqgd)
3476 val = bfqgd->weight;
3477
3478 seq_printf(sf, "%u\n", val);
3479
3480 return 0;
3481}
3482
3483static int bfq_io_set_weight_legacy(struct cgroup_subsys_state *css,
3484 struct cftype *cftype,
3485 u64 val)
3486{
3487 struct blkcg *blkcg = css_to_blkcg(css);
3488 struct bfq_group_data *bfqgd = blkcg_to_bfqgd(blkcg);
3489 struct blkcg_gq *blkg;
3490 int ret = -ERANGE;
3491
3492 if (val < BFQ_MIN_WEIGHT || val > BFQ_MAX_WEIGHT)
3493 return ret;
3494
3495 ret = 0;
3496 spin_lock_irq(&blkcg->lock);
3497 bfqgd->weight = (unsigned short)val;
3498 hlist_for_each_entry(blkg, &blkcg->blkg_list, blkcg_node) {
3499 struct bfq_group *bfqg = blkg_to_bfqg(blkg);
3500
3501 if (!bfqg)
3502 continue;
3503 /*
3504 * Setting the prio_changed flag of the entity
3505 * to 1 with new_weight == weight would re-set
3506 * the value of the weight to its ioprio mapping.
3507 * Set the flag only if necessary.
3508 */
3509 if ((unsigned short)val != bfqg->entity.new_weight) {
3510 bfqg->entity.new_weight = (unsigned short)val;
3511 /*
3512 * Make sure that the above new value has been
3513 * stored in bfqg->entity.new_weight before
3514 * setting the prio_changed flag. In fact,
3515 * this flag may be read asynchronously (in
3516 * critical sections protected by a different
3517 * lock than that held here), and finding this
3518 * flag set may cause the execution of the code
3519 * for updating parameters whose value may
3520 * depend also on bfqg->entity.new_weight (in
3521 * __bfq_entity_update_weight_prio).
3522 * This barrier makes sure that the new value
3523 * of bfqg->entity.new_weight is correctly
3524 * seen in that code.
3525 */
3526 smp_wmb();
3527 bfqg->entity.prio_changed = 1;
3528 }
3529 }
3530 spin_unlock_irq(&blkcg->lock);
3531
3532 return ret;
3533}
3534
3535static ssize_t bfq_io_set_weight(struct kernfs_open_file *of,
3536 char *buf, size_t nbytes,
3537 loff_t off)
3538{
3539 u64 weight;
3540 /* First unsigned long found in the file is used */
3541 int ret = kstrtoull(strim(buf), 0, &weight);
3542
3543 if (ret)
3544 return ret;
3545
3546 return bfq_io_set_weight_legacy(of_css(of), NULL, weight);
3547}
3548
3549static int bfqg_print_stat(struct seq_file *sf, void *v)
3550{
3551 blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), blkg_prfill_stat,
3552 &blkcg_policy_bfq, seq_cft(sf)->private, false);
3553 return 0;
3554}
3555
3556static int bfqg_print_rwstat(struct seq_file *sf, void *v)
3557{
3558 blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), blkg_prfill_rwstat,
3559 &blkcg_policy_bfq, seq_cft(sf)->private, true);
3560 return 0;
3561}
3562
3563static u64 bfqg_prfill_stat_recursive(struct seq_file *sf,
3564 struct blkg_policy_data *pd, int off)
3565{
3566 u64 sum = blkg_stat_recursive_sum(pd_to_blkg(pd),
3567 &blkcg_policy_bfq, off);
3568 return __blkg_prfill_u64(sf, pd, sum);
3569}
3570
3571static u64 bfqg_prfill_rwstat_recursive(struct seq_file *sf,
3572 struct blkg_policy_data *pd, int off)
3573{
3574 struct blkg_rwstat sum = blkg_rwstat_recursive_sum(pd_to_blkg(pd),
3575 &blkcg_policy_bfq,
3576 off);
3577 return __blkg_prfill_rwstat(sf, pd, &sum);
3578}
3579
3580static int bfqg_print_stat_recursive(struct seq_file *sf, void *v)
3581{
3582 blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
3583 bfqg_prfill_stat_recursive, &blkcg_policy_bfq,
3584 seq_cft(sf)->private, false);
3585 return 0;
3586}
3587
3588static int bfqg_print_rwstat_recursive(struct seq_file *sf, void *v)
3589{
3590 blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
3591 bfqg_prfill_rwstat_recursive, &blkcg_policy_bfq,
3592 seq_cft(sf)->private, true);
3593 return 0;
3594}
3595
3596static u64 bfqg_prfill_sectors(struct seq_file *sf, struct blkg_policy_data *pd,
3597 int off)
3598{
3599 u64 sum = blkg_rwstat_total(&pd->blkg->stat_bytes);
3600
3601 return __blkg_prfill_u64(sf, pd, sum >> 9);
3602}
3603
3604static int bfqg_print_stat_sectors(struct seq_file *sf, void *v)
3605{
3606 blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
3607 bfqg_prfill_sectors, &blkcg_policy_bfq, 0, false);
3608 return 0;
3609}
3610
3611static u64 bfqg_prfill_sectors_recursive(struct seq_file *sf,
3612 struct blkg_policy_data *pd, int off)
3613{
3614 struct blkg_rwstat tmp = blkg_rwstat_recursive_sum(pd->blkg, NULL,
3615 offsetof(struct blkcg_gq, stat_bytes));
3616 u64 sum = atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_READ]) +
3617 atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_WRITE]);
3618
3619 return __blkg_prfill_u64(sf, pd, sum >> 9);
3620}
3621
3622static int bfqg_print_stat_sectors_recursive(struct seq_file *sf, void *v)
3623{
3624 blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
3625 bfqg_prfill_sectors_recursive, &blkcg_policy_bfq, 0,
3626 false);
3627 return 0;
3628}
3629
3630static u64 bfqg_prfill_avg_queue_size(struct seq_file *sf,
3631 struct blkg_policy_data *pd, int off)
3632{
3633 struct bfq_group *bfqg = pd_to_bfqg(pd);
3634 u64 samples = blkg_stat_read(&bfqg->stats.avg_queue_size_samples);
3635 u64 v = 0;
3636
3637 if (samples) {
3638 v = blkg_stat_read(&bfqg->stats.avg_queue_size_sum);
3639 v = div64_u64(v, samples);
3640 }
3641 __blkg_prfill_u64(sf, pd, v);
3642 return 0;
3643}
3644
3645/* print avg_queue_size */
3646static int bfqg_print_avg_queue_size(struct seq_file *sf, void *v)
3647{
3648 blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
3649 bfqg_prfill_avg_queue_size, &blkcg_policy_bfq,
3650 0, false);
3651 return 0;
3652}
3653
3654static struct bfq_group *
3655bfq_create_group_hierarchy(struct bfq_data *bfqd, int node)
3656{
3657 int ret;
3658
3659 ret = blkcg_activate_policy(bfqd->queue, &blkcg_policy_bfq);
3660 if (ret)
3661 return NULL;
3662
3663 return blkg_to_bfqg(bfqd->queue->root_blkg);
3664}
3665
3666static struct cftype bfq_blkcg_legacy_files[] = {
3667 {
3668 .name = "bfq.weight",
3669 .flags = CFTYPE_NOT_ON_ROOT,
3670 .seq_show = bfq_io_show_weight,
3671 .write_u64 = bfq_io_set_weight_legacy,
3672 },
3673
3674 /* statistics, covers only the tasks in the bfqg */
3675 {
3676 .name = "bfq.time",
3677 .private = offsetof(struct bfq_group, stats.time),
3678 .seq_show = bfqg_print_stat,
3679 },
3680 {
3681 .name = "bfq.sectors",
3682 .seq_show = bfqg_print_stat_sectors,
3683 },
3684 {
3685 .name = "bfq.io_service_bytes",
3686 .private = (unsigned long)&blkcg_policy_bfq,
3687 .seq_show = blkg_print_stat_bytes,
3688 },
3689 {
3690 .name = "bfq.io_serviced",
3691 .private = (unsigned long)&blkcg_policy_bfq,
3692 .seq_show = blkg_print_stat_ios,
3693 },
3694 {
3695 .name = "bfq.io_service_time",
3696 .private = offsetof(struct bfq_group, stats.service_time),
3697 .seq_show = bfqg_print_rwstat,
3698 },
3699 {
3700 .name = "bfq.io_wait_time",
3701 .private = offsetof(struct bfq_group, stats.wait_time),
3702 .seq_show = bfqg_print_rwstat,
3703 },
3704 {
3705 .name = "bfq.io_merged",
3706 .private = offsetof(struct bfq_group, stats.merged),
3707 .seq_show = bfqg_print_rwstat,
3708 },
3709 {
3710 .name = "bfq.io_queued",
3711 .private = offsetof(struct bfq_group, stats.queued),
3712 .seq_show = bfqg_print_rwstat,
3713 },
3714
3715 /* the same statictics which cover the bfqg and its descendants */
3716 {
3717 .name = "bfq.time_recursive",
3718 .private = offsetof(struct bfq_group, stats.time),
3719 .seq_show = bfqg_print_stat_recursive,
3720 },
3721 {
3722 .name = "bfq.sectors_recursive",
3723 .seq_show = bfqg_print_stat_sectors_recursive,
3724 },
3725 {
3726 .name = "bfq.io_service_bytes_recursive",
3727 .private = (unsigned long)&blkcg_policy_bfq,
3728 .seq_show = blkg_print_stat_bytes_recursive,
3729 },
3730 {
3731 .name = "bfq.io_serviced_recursive",
3732 .private = (unsigned long)&blkcg_policy_bfq,
3733 .seq_show = blkg_print_stat_ios_recursive,
3734 },
3735 {
3736 .name = "bfq.io_service_time_recursive",
3737 .private = offsetof(struct bfq_group, stats.service_time),
3738 .seq_show = bfqg_print_rwstat_recursive,
3739 },
3740 {
3741 .name = "bfq.io_wait_time_recursive",
3742 .private = offsetof(struct bfq_group, stats.wait_time),
3743 .seq_show = bfqg_print_rwstat_recursive,
3744 },
3745 {
3746 .name = "bfq.io_merged_recursive",
3747 .private = offsetof(struct bfq_group, stats.merged),
3748 .seq_show = bfqg_print_rwstat_recursive,
3749 },
3750 {
3751 .name = "bfq.io_queued_recursive",
3752 .private = offsetof(struct bfq_group, stats.queued),
3753 .seq_show = bfqg_print_rwstat_recursive,
3754 },
3755 {
3756 .name = "bfq.avg_queue_size",
3757 .seq_show = bfqg_print_avg_queue_size,
3758 },
3759 {
3760 .name = "bfq.group_wait_time",
3761 .private = offsetof(struct bfq_group, stats.group_wait_time),
3762 .seq_show = bfqg_print_stat,
3763 },
3764 {
3765 .name = "bfq.idle_time",
3766 .private = offsetof(struct bfq_group, stats.idle_time),
3767 .seq_show = bfqg_print_stat,
3768 },
3769 {
3770 .name = "bfq.empty_time",
3771 .private = offsetof(struct bfq_group, stats.empty_time),
3772 .seq_show = bfqg_print_stat,
3773 },
3774 {
3775 .name = "bfq.dequeue",
3776 .private = offsetof(struct bfq_group, stats.dequeue),
3777 .seq_show = bfqg_print_stat,
3778 },
3779 { } /* terminate */
3780};
3781
3782static struct cftype bfq_blkg_files[] = {
3783 {
3784 .name = "bfq.weight",
3785 .flags = CFTYPE_NOT_ON_ROOT,
3786 .seq_show = bfq_io_show_weight,
3787 .write = bfq_io_set_weight,
3788 },
3789 {} /* terminate */
3790};
3791
3792#else /* CONFIG_BFQ_GROUP_IOSCHED */
3793
3794static inline void bfqg_stats_update_io_add(struct bfq_group *bfqg,
3795 struct bfq_queue *bfqq, unsigned int op) { }
3796static inline void
3797bfqg_stats_update_io_remove(struct bfq_group *bfqg, unsigned int op) { }
3798static inline void
3799bfqg_stats_update_io_merged(struct bfq_group *bfqg, unsigned int op) { }
3800static inline void bfqg_stats_update_completion(struct bfq_group *bfqg,
3801 uint64_t start_time, uint64_t io_start_time,
3802 unsigned int op) { }
3803static inline void
3804bfqg_stats_set_start_group_wait_time(struct bfq_group *bfqg,
3805 struct bfq_group *curr_bfqg) { }
3806static inline void bfqg_stats_end_empty_time(struct bfqg_stats *stats) { }
3807static inline void bfqg_stats_update_dequeue(struct bfq_group *bfqg) { }
3808static inline void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg) { }
3809static inline void bfqg_stats_update_idle_time(struct bfq_group *bfqg) { }
3810static inline void bfqg_stats_set_start_idle_time(struct bfq_group *bfqg) { }
3811static inline void bfqg_stats_update_avg_queue_size(struct bfq_group *bfqg) { }
3812
3813static void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq,
3814 struct bfq_group *bfqg) {}
3815
3816static void bfq_init_entity(struct bfq_entity *entity,
3817 struct bfq_group *bfqg)
3818{
3819 struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity);
3820
3821 entity->weight = entity->new_weight;
3822 entity->orig_weight = entity->new_weight;
3823 if (bfqq) {
3824 bfqq->ioprio = bfqq->new_ioprio;
3825 bfqq->ioprio_class = bfqq->new_ioprio_class;
3826 }
3827 entity->sched_data = &bfqg->sched_data;
3828}
3829
3830static void bfq_bic_update_cgroup(struct bfq_io_cq *bic, struct bio *bio) {}
3831
3832static void bfq_end_wr_async(struct bfq_data *bfqd)
3833{
3834 bfq_end_wr_async_queues(bfqd, bfqd->root_group);
3835}
3836
3837static struct bfq_group *bfq_find_set_group(struct bfq_data *bfqd,
3838 struct blkcg *blkcg)
3839{
3840 return bfqd->root_group;
3841}
3842
3843static struct bfq_group *bfqq_group(struct bfq_queue *bfqq)
3844{
3845 return bfqq->bfqd->root_group;
3846}
3847
3848static struct bfq_group *bfq_create_group_hierarchy(struct bfq_data *bfqd,
3849 int node)
3850{
3851 struct bfq_group *bfqg;
3852 int i;
3853
3854 bfqg = kmalloc_node(sizeof(*bfqg), GFP_KERNEL | __GFP_ZERO, node);
3855 if (!bfqg)
3856 return NULL;
3857
3858 for (i = 0; i < BFQ_IOPRIO_CLASSES; i++)
3859 bfqg->sched_data.service_tree[i] = BFQ_SERVICE_TREE_INIT;
3860
3861 return bfqg;
3862}
3863#endif /* CONFIG_BFQ_GROUP_IOSCHED */
3864
3865#define bfq_class_idle(bfqq) ((bfqq)->ioprio_class == IOPRIO_CLASS_IDLE) 301#define bfq_class_idle(bfqq) ((bfqq)->ioprio_class == IOPRIO_CLASS_IDLE)
3866#define bfq_class_rt(bfqq) ((bfqq)->ioprio_class == IOPRIO_CLASS_RT) 302#define bfq_class_rt(bfqq) ((bfqq)->ioprio_class == IOPRIO_CLASS_RT)
3867 303
@@ -4002,7 +438,7 @@ bfq_rq_pos_tree_lookup(struct bfq_data *bfqd, struct rb_root *root,
4002 return bfqq; 438 return bfqq;
4003} 439}
4004 440
4005static void bfq_pos_tree_add_move(struct bfq_data *bfqd, struct bfq_queue *bfqq) 441void bfq_pos_tree_add_move(struct bfq_data *bfqd, struct bfq_queue *bfqq)
4006{ 442{
4007 struct rb_node **p, *parent; 443 struct rb_node **p, *parent;
4008 struct bfq_queue *__bfqq; 444 struct bfq_queue *__bfqq;
@@ -4091,9 +527,8 @@ static bool bfq_symmetric_scenario(struct bfq_data *bfqd)
4091 * In most scenarios, the rate at which nodes are created/destroyed 527 * In most scenarios, the rate at which nodes are created/destroyed
4092 * should be low too. 528 * should be low too.
4093 */ 529 */
4094static void bfq_weights_tree_add(struct bfq_data *bfqd, 530void bfq_weights_tree_add(struct bfq_data *bfqd, struct bfq_entity *entity,
4095 struct bfq_entity *entity, 531 struct rb_root *root)
4096 struct rb_root *root)
4097{ 532{
4098 struct rb_node **new = &(root->rb_node), *parent = NULL; 533 struct rb_node **new = &(root->rb_node), *parent = NULL;
4099 534
@@ -4161,9 +596,8 @@ inc_counter:
4161 * See the comments to the function bfq_weights_tree_add() for considerations 596 * See the comments to the function bfq_weights_tree_add() for considerations
4162 * about overhead. 597 * about overhead.
4163 */ 598 */
4164static void bfq_weights_tree_remove(struct bfq_data *bfqd, 599void bfq_weights_tree_remove(struct bfq_data *bfqd, struct bfq_entity *entity,
4165 struct bfq_entity *entity, 600 struct rb_root *root)
4166 struct rb_root *root)
4167{ 601{
4168 if (!entity->weight_counter) 602 if (!entity->weight_counter)
4169 return; 603 return;
@@ -4580,11 +1014,6 @@ static int bfq_min_budget(struct bfq_data *bfqd)
4580 return bfqd->bfq_max_budget / 32; 1014 return bfqd->bfq_max_budget / 32;
4581} 1015}
4582 1016
4583static void bfq_bfqq_expire(struct bfq_data *bfqd,
4584 struct bfq_queue *bfqq,
4585 bool compensate,
4586 enum bfqq_expiration reason);
4587
4588/* 1017/*
4589 * The next function, invoked after the input queue bfqq switches from 1018 * The next function, invoked after the input queue bfqq switches from
4590 * idle to busy, updates the budget of bfqq. The function also tells 1019 * idle to busy, updates the budget of bfqq. The function also tells
@@ -5275,8 +1704,8 @@ static void bfq_bfqq_end_wr(struct bfq_queue *bfqq)
5275 bfqq->entity.prio_changed = 1; 1704 bfqq->entity.prio_changed = 1;
5276} 1705}
5277 1706
5278static void bfq_end_wr_async_queues(struct bfq_data *bfqd, 1707void bfq_end_wr_async_queues(struct bfq_data *bfqd,
5279 struct bfq_group *bfqg) 1708 struct bfq_group *bfqg)
5280{ 1709{
5281 int i, j; 1710 int i, j;
5282 1711
@@ -6495,10 +2924,10 @@ static unsigned long bfq_smallest_from_now(void)
6495 * former on a timeslice basis, without violating service domain 2924 * former on a timeslice basis, without violating service domain
6496 * guarantees among the latter. 2925 * guarantees among the latter.
6497 */ 2926 */
6498static void bfq_bfqq_expire(struct bfq_data *bfqd, 2927void bfq_bfqq_expire(struct bfq_data *bfqd,
6499 struct bfq_queue *bfqq, 2928 struct bfq_queue *bfqq,
6500 bool compensate, 2929 bool compensate,
6501 enum bfqq_expiration reason) 2930 enum bfqq_expiration reason)
6502{ 2931{
6503 bool slow; 2932 bool slow;
6504 unsigned long delta = 0; 2933 unsigned long delta = 0;
@@ -7204,7 +3633,7 @@ static struct request *bfq_dispatch_request(struct blk_mq_hw_ctx *hctx)
7204 * Scheduler lock must be held here. Recall not to use bfqq after calling 3633 * Scheduler lock must be held here. Recall not to use bfqq after calling
7205 * this function on it. 3634 * this function on it.
7206 */ 3635 */
7207static void bfq_put_queue(struct bfq_queue *bfqq) 3636void bfq_put_queue(struct bfq_queue *bfqq)
7208{ 3637{
7209#ifdef CONFIG_BFQ_GROUP_IOSCHED 3638#ifdef CONFIG_BFQ_GROUP_IOSCHED
7210 struct bfq_group *bfqg = bfqq_group(bfqq); 3639 struct bfq_group *bfqg = bfqq_group(bfqq);
@@ -7345,6 +3774,10 @@ bfq_set_next_ioprio_data(struct bfq_queue *bfqq, struct bfq_io_cq *bic)
7345 bfqq->entity.prio_changed = 1; 3774 bfqq->entity.prio_changed = 1;
7346} 3775}
7347 3776
3777static struct bfq_queue *bfq_get_queue(struct bfq_data *bfqd,
3778 struct bio *bio, bool is_sync,
3779 struct bfq_io_cq *bic);
3780
7348static void bfq_check_ioprio_change(struct bfq_io_cq *bic, struct bio *bio) 3781static void bfq_check_ioprio_change(struct bfq_io_cq *bic, struct bio *bio)
7349{ 3782{
7350 struct bfq_data *bfqd = bic_to_bfqd(bic); 3783 struct bfq_data *bfqd = bic_to_bfqd(bic);
@@ -8121,7 +4554,7 @@ static void __bfq_put_async_bfqq(struct bfq_data *bfqd,
8121 * we reparent them to the root cgroup (i.e., the only one that will 4554 * we reparent them to the root cgroup (i.e., the only one that will
8122 * exist for sure until all the requests on a device are gone). 4555 * exist for sure until all the requests on a device are gone).
8123 */ 4556 */
8124static void bfq_put_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg) 4557void bfq_put_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg)
8125{ 4558{
8126 int i, j; 4559 int i, j;
8127 4560
@@ -8537,24 +4970,6 @@ static struct elevator_type iosched_bfq_mq = {
8537 .elevator_owner = THIS_MODULE, 4970 .elevator_owner = THIS_MODULE,
8538}; 4971};
8539 4972
8540#ifdef CONFIG_BFQ_GROUP_IOSCHED
8541static struct blkcg_policy blkcg_policy_bfq = {
8542 .dfl_cftypes = bfq_blkg_files,
8543 .legacy_cftypes = bfq_blkcg_legacy_files,
8544
8545 .cpd_alloc_fn = bfq_cpd_alloc,
8546 .cpd_init_fn = bfq_cpd_init,
8547 .cpd_bind_fn = bfq_cpd_init,
8548 .cpd_free_fn = bfq_cpd_free,
8549
8550 .pd_alloc_fn = bfq_pd_alloc,
8551 .pd_init_fn = bfq_pd_init,
8552 .pd_offline_fn = bfq_pd_offline,
8553 .pd_free_fn = bfq_pd_free,
8554 .pd_reset_stats_fn = bfq_pd_reset_stats,
8555};
8556#endif
8557
8558static int __init bfq_init(void) 4973static int __init bfq_init(void)
8559{ 4974{
8560 int ret; 4975 int ret;
generated by cgit v1.2.2 (git 2.25.0) at 2025-09-17 08:38:27 -0400