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1 | /* |
2 | * CFQ, or complete fairness queueing, disk scheduler. |
3 | * |
4 | * Based on ideas from a previously unfinished io |
5 | * scheduler (round robin per-process disk scheduling) and Andrea Arcangeli. |
6 | * |
7 | * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk> |
8 | */ |
9 | #include <linux/module.h> |
10 | #include <linux/slab.h> |
11 | #include <linux/blkdev.h> |
12 | #include <linux/elevator.h> |
13 | #include <linux/jiffies.h> |
14 | #include <linux/rbtree.h> |
15 | #include <linux/ioprio.h> |
16 | #include <linux/blktrace_api.h> |
17 | #include "blk.h" |
18 | #include "blk-cgroup.h" |
19 | |
20 | /* |
21 | * tunables |
22 | */ |
23 | /* max queue in one round of service */ |
24 | static const int cfq_quantum = 8; |
25 | static const int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 }; |
26 | /* maximum backwards seek, in KiB */ |
27 | static const int cfq_back_max = 16 * 1024; |
28 | /* penalty of a backwards seek */ |
29 | static const int cfq_back_penalty = 2; |
30 | static const int cfq_slice_sync = HZ / 10; |
31 | static int cfq_slice_async = HZ / 25; |
32 | static const int cfq_slice_async_rq = 2; |
33 | static int cfq_slice_idle = HZ / 125; |
34 | static int cfq_group_idle = HZ / 125; |
35 | static const int cfq_target_latency = HZ * 3/10; /* 300 ms */ |
36 | static const int cfq_hist_divisor = 4; |
37 | |
38 | /* |
39 | * offset from end of service tree |
40 | */ |
41 | #define CFQ_IDLE_DELAY (HZ / 5) |
42 | |
43 | /* |
44 | * below this threshold, we consider thinktime immediate |
45 | */ |
46 | #define CFQ_MIN_TT (2) |
47 | |
48 | #define CFQ_SLICE_SCALE (5) |
49 | #define CFQ_HW_QUEUE_MIN (5) |
50 | #define CFQ_SERVICE_SHIFT 12 |
51 | |
52 | #define CFQQ_SEEK_THR (sector_t)(8 * 100) |
53 | #define CFQQ_CLOSE_THR (sector_t)(8 * 1024) |
54 | #define CFQQ_SECT_THR_NONROT (sector_t)(2 * 32) |
55 | #define CFQQ_SEEKY(cfqq) (hweight32(cfqq->seek_history) > 32/8) |
56 | |
57 | #define RQ_CIC(rq) icq_to_cic((rq)->elv.icq) |
58 | #define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elv.priv[0]) |
59 | #define RQ_CFQG(rq) (struct cfq_group *) ((rq)->elv.priv[1]) |
60 | |
61 | static struct kmem_cache *cfq_pool; |
62 | |
63 | #define CFQ_PRIO_LISTS IOPRIO_BE_NR |
64 | #define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE) |
65 | #define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT) |
66 | |
67 | #define sample_valid(samples) ((samples) > 80) |
68 | #define rb_entry_cfqg(node) rb_entry((node), struct cfq_group, rb_node) |
69 | |
70 | struct cfq_ttime { |
71 | unsigned long last_end_request; |
72 | |
73 | unsigned long ttime_total; |
74 | unsigned long ttime_samples; |
75 | unsigned long ttime_mean; |
76 | }; |
77 | |
78 | /* |
79 | * Most of our rbtree usage is for sorting with min extraction, so |
80 | * if we cache the leftmost node we don't have to walk down the tree |
81 | * to find it. Idea borrowed from Ingo Molnars CFS scheduler. We should |
82 | * move this into the elevator for the rq sorting as well. |
83 | */ |
84 | struct cfq_rb_root { |
85 | struct rb_root rb; |
86 | struct rb_node *left; |
87 | unsigned count; |
88 | u64 min_vdisktime; |
89 | struct cfq_ttime ttime; |
90 | }; |
91 | #define CFQ_RB_ROOT (struct cfq_rb_root) { .rb = RB_ROOT, \ |
92 | .ttime = {.last_end_request = jiffies,},} |
93 | |
94 | /* |
95 | * Per process-grouping structure |
96 | */ |
97 | struct cfq_queue { |
98 | /* reference count */ |
99 | int ref; |
100 | /* various state flags, see below */ |
101 | unsigned int flags; |
102 | /* parent cfq_data */ |
103 | struct cfq_data *cfqd; |
104 | /* service_tree member */ |
105 | struct rb_node rb_node; |
106 | /* service_tree key */ |
107 | unsigned long rb_key; |
108 | /* prio tree member */ |
109 | struct rb_node p_node; |
110 | /* prio tree root we belong to, if any */ |
111 | struct rb_root *p_root; |
112 | /* sorted list of pending requests */ |
113 | struct rb_root sort_list; |
114 | /* if fifo isn't expired, next request to serve */ |
115 | struct request *next_rq; |
116 | /* requests queued in sort_list */ |
117 | int queued[2]; |
118 | /* currently allocated requests */ |
119 | int allocated[2]; |
120 | /* fifo list of requests in sort_list */ |
121 | struct list_head fifo; |
122 | |
123 | /* time when queue got scheduled in to dispatch first request. */ |
124 | unsigned long dispatch_start; |
125 | unsigned int allocated_slice; |
126 | unsigned int slice_dispatch; |
127 | /* time when first request from queue completed and slice started. */ |
128 | unsigned long slice_start; |
129 | unsigned long slice_end; |
130 | long slice_resid; |
131 | |
132 | /* pending priority requests */ |
133 | int prio_pending; |
134 | /* number of requests that are on the dispatch list or inside driver */ |
135 | int dispatched; |
136 | |
137 | /* io prio of this group */ |
138 | unsigned short ioprio, org_ioprio; |
139 | unsigned short ioprio_class; |
140 | |
141 | pid_t pid; |
142 | |
143 | u32 seek_history; |
144 | sector_t last_request_pos; |
145 | |
146 | struct cfq_rb_root *service_tree; |
147 | struct cfq_queue *new_cfqq; |
148 | struct cfq_group *cfqg; |
149 | /* Number of sectors dispatched from queue in single dispatch round */ |
150 | unsigned long nr_sectors; |
151 | }; |
152 | |
153 | /* |
154 | * First index in the service_trees. |
155 | * IDLE is handled separately, so it has negative index |
156 | */ |
157 | enum wl_class_t { |
158 | BE_WORKLOAD = 0, |
159 | RT_WORKLOAD = 1, |
160 | IDLE_WORKLOAD = 2, |
161 | CFQ_PRIO_NR, |
162 | }; |
163 | |
164 | /* |
165 | * Second index in the service_trees. |
166 | */ |
167 | enum wl_type_t { |
168 | ASYNC_WORKLOAD = 0, |
169 | SYNC_NOIDLE_WORKLOAD = 1, |
170 | SYNC_WORKLOAD = 2 |
171 | }; |
172 | |
173 | struct cfqg_stats { |
174 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
175 | /* total bytes transferred */ |
176 | struct blkg_rwstat service_bytes; |
177 | /* total IOs serviced, post merge */ |
178 | struct blkg_rwstat serviced; |
179 | /* number of ios merged */ |
180 | struct blkg_rwstat merged; |
181 | /* total time spent on device in ns, may not be accurate w/ queueing */ |
182 | struct blkg_rwstat service_time; |
183 | /* total time spent waiting in scheduler queue in ns */ |
184 | struct blkg_rwstat wait_time; |
185 | /* number of IOs queued up */ |
186 | struct blkg_rwstat queued; |
187 | /* total sectors transferred */ |
188 | struct blkg_stat sectors; |
189 | /* total disk time and nr sectors dispatched by this group */ |
190 | struct blkg_stat time; |
191 | #ifdef CONFIG_DEBUG_BLK_CGROUP |
192 | /* time not charged to this cgroup */ |
193 | struct blkg_stat unaccounted_time; |
194 | /* sum of number of ios queued across all samples */ |
195 | struct blkg_stat avg_queue_size_sum; |
196 | /* count of samples taken for average */ |
197 | struct blkg_stat avg_queue_size_samples; |
198 | /* how many times this group has been removed from service tree */ |
199 | struct blkg_stat dequeue; |
200 | /* total time spent waiting for it to be assigned a timeslice. */ |
201 | struct blkg_stat group_wait_time; |
202 | /* time spent idling for this blkcg_gq */ |
203 | struct blkg_stat idle_time; |
204 | /* total time with empty current active q with other requests queued */ |
205 | struct blkg_stat empty_time; |
206 | /* fields after this shouldn't be cleared on stat reset */ |
207 | uint64_t start_group_wait_time; |
208 | uint64_t start_idle_time; |
209 | uint64_t start_empty_time; |
210 | uint16_t flags; |
211 | #endif /* CONFIG_DEBUG_BLK_CGROUP */ |
212 | #endif /* CONFIG_CFQ_GROUP_IOSCHED */ |
213 | }; |
214 | |
215 | /* This is per cgroup per device grouping structure */ |
216 | struct cfq_group { |
217 | /* must be the first member */ |
218 | struct blkg_policy_data pd; |
219 | |
220 | /* group service_tree member */ |
221 | struct rb_node rb_node; |
222 | |
223 | /* group service_tree key */ |
224 | u64 vdisktime; |
225 | |
226 | /* |
227 | * The number of active cfqgs and sum of their weights under this |
228 | * cfqg. This covers this cfqg's leaf_weight and all children's |
229 | * weights, but does not cover weights of further descendants. |
230 | * |
231 | * If a cfqg is on the service tree, it's active. An active cfqg |
232 | * also activates its parent and contributes to the children_weight |
233 | * of the parent. |
234 | */ |
235 | int nr_active; |
236 | unsigned int children_weight; |
237 | |
238 | /* |
239 | * vfraction is the fraction of vdisktime that the tasks in this |
240 | * cfqg are entitled to. This is determined by compounding the |
241 | * ratios walking up from this cfqg to the root. |
242 | * |
243 | * It is in fixed point w/ CFQ_SERVICE_SHIFT and the sum of all |
244 | * vfractions on a service tree is approximately 1. The sum may |
245 | * deviate a bit due to rounding errors and fluctuations caused by |
246 | * cfqgs entering and leaving the service tree. |
247 | */ |
248 | unsigned int vfraction; |
249 | |
250 | /* |
251 | * There are two weights - (internal) weight is the weight of this |
252 | * cfqg against the sibling cfqgs. leaf_weight is the wight of |
253 | * this cfqg against the child cfqgs. For the root cfqg, both |
254 | * weights are kept in sync for backward compatibility. |
255 | */ |
256 | unsigned int weight; |
257 | unsigned int new_weight; |
258 | unsigned int dev_weight; |
259 | |
260 | unsigned int leaf_weight; |
261 | unsigned int new_leaf_weight; |
262 | unsigned int dev_leaf_weight; |
263 | |
264 | /* number of cfqq currently on this group */ |
265 | int nr_cfqq; |
266 | |
267 | /* |
268 | * Per group busy queues average. Useful for workload slice calc. We |
269 | * create the array for each prio class but at run time it is used |
270 | * only for RT and BE class and slot for IDLE class remains unused. |
271 | * This is primarily done to avoid confusion and a gcc warning. |
272 | */ |
273 | unsigned int busy_queues_avg[CFQ_PRIO_NR]; |
274 | /* |
275 | * rr lists of queues with requests. We maintain service trees for |
276 | * RT and BE classes. These trees are subdivided in subclasses |
277 | * of SYNC, SYNC_NOIDLE and ASYNC based on workload type. For IDLE |
278 | * class there is no subclassification and all the cfq queues go on |
279 | * a single tree service_tree_idle. |
280 | * Counts are embedded in the cfq_rb_root |
281 | */ |
282 | struct cfq_rb_root service_trees[2][3]; |
283 | struct cfq_rb_root service_tree_idle; |
284 | |
285 | unsigned long saved_wl_slice; |
286 | enum wl_type_t saved_wl_type; |
287 | enum wl_class_t saved_wl_class; |
288 | |
289 | /* number of requests that are on the dispatch list or inside driver */ |
290 | int dispatched; |
291 | struct cfq_ttime ttime; |
292 | struct cfqg_stats stats; /* stats for this cfqg */ |
293 | struct cfqg_stats dead_stats; /* stats pushed from dead children */ |
294 | }; |
295 | |
296 | struct cfq_io_cq { |
297 | struct io_cq icq; /* must be the first member */ |
298 | struct cfq_queue *cfqq[2]; |
299 | struct cfq_ttime ttime; |
300 | int ioprio; /* the current ioprio */ |
301 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
302 | uint64_t blkcg_id; /* the current blkcg ID */ |
303 | #endif |
304 | }; |
305 | |
306 | /* |
307 | * Per block device queue structure |
308 | */ |
309 | struct cfq_data { |
310 | struct request_queue *queue; |
311 | /* Root service tree for cfq_groups */ |
312 | struct cfq_rb_root grp_service_tree; |
313 | struct cfq_group *root_group; |
314 | |
315 | /* |
316 | * The priority currently being served |
317 | */ |
318 | enum wl_class_t serving_wl_class; |
319 | enum wl_type_t serving_wl_type; |
320 | unsigned long workload_expires; |
321 | struct cfq_group *serving_group; |
322 | |
323 | /* |
324 | * Each priority tree is sorted by next_request position. These |
325 | * trees are used when determining if two or more queues are |
326 | * interleaving requests (see cfq_close_cooperator). |
327 | */ |
328 | struct rb_root prio_trees[CFQ_PRIO_LISTS]; |
329 | |
330 | unsigned int busy_queues; |
331 | unsigned int busy_sync_queues; |
332 | |
333 | int rq_in_driver; |
334 | int rq_in_flight[2]; |
335 | |
336 | /* |
337 | * queue-depth detection |
338 | */ |
339 | int rq_queued; |
340 | int hw_tag; |
341 | /* |
342 | * hw_tag can be |
343 | * -1 => indeterminate, (cfq will behave as if NCQ is present, to allow better detection) |
344 | * 1 => NCQ is present (hw_tag_est_depth is the estimated max depth) |
345 | * 0 => no NCQ |
346 | */ |
347 | int hw_tag_est_depth; |
348 | unsigned int hw_tag_samples; |
349 | |
350 | /* |
351 | * idle window management |
352 | */ |
353 | struct timer_list idle_slice_timer; |
354 | struct work_struct unplug_work; |
355 | |
356 | struct cfq_queue *active_queue; |
357 | struct cfq_io_cq *active_cic; |
358 | |
359 | /* |
360 | * async queue for each priority case |
361 | */ |
362 | struct cfq_queue *async_cfqq[2][IOPRIO_BE_NR]; |
363 | struct cfq_queue *async_idle_cfqq; |
364 | |
365 | sector_t last_position; |
366 | |
367 | /* |
368 | * tunables, see top of file |
369 | */ |
370 | unsigned int cfq_quantum; |
371 | unsigned int cfq_fifo_expire[2]; |
372 | unsigned int cfq_back_penalty; |
373 | unsigned int cfq_back_max; |
374 | unsigned int cfq_slice[2]; |
375 | unsigned int cfq_slice_async_rq; |
376 | unsigned int cfq_slice_idle; |
377 | unsigned int cfq_group_idle; |
378 | unsigned int cfq_latency; |
379 | unsigned int cfq_target_latency; |
380 | |
381 | /* |
382 | * Fallback dummy cfqq for extreme OOM conditions |
383 | */ |
384 | struct cfq_queue oom_cfqq; |
385 | |
386 | unsigned long last_delayed_sync; |
387 | }; |
388 | |
389 | static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd); |
390 | |
391 | static struct cfq_rb_root *st_for(struct cfq_group *cfqg, |
392 | enum wl_class_t class, |
393 | enum wl_type_t type) |
394 | { |
395 | if (!cfqg) |
396 | return NULL; |
397 | |
398 | if (class == IDLE_WORKLOAD) |
399 | return &cfqg->service_tree_idle; |
400 | |
401 | return &cfqg->service_trees[class][type]; |
402 | } |
403 | |
404 | enum cfqq_state_flags { |
405 | CFQ_CFQQ_FLAG_on_rr = 0, /* on round-robin busy list */ |
406 | CFQ_CFQQ_FLAG_wait_request, /* waiting for a request */ |
407 | CFQ_CFQQ_FLAG_must_dispatch, /* must be allowed a dispatch */ |
408 | CFQ_CFQQ_FLAG_must_alloc_slice, /* per-slice must_alloc flag */ |
409 | CFQ_CFQQ_FLAG_fifo_expire, /* FIFO checked in this slice */ |
410 | CFQ_CFQQ_FLAG_idle_window, /* slice idling enabled */ |
411 | CFQ_CFQQ_FLAG_prio_changed, /* task priority has changed */ |
412 | CFQ_CFQQ_FLAG_slice_new, /* no requests dispatched in slice */ |
413 | CFQ_CFQQ_FLAG_sync, /* synchronous queue */ |
414 | CFQ_CFQQ_FLAG_coop, /* cfqq is shared */ |
415 | CFQ_CFQQ_FLAG_split_coop, /* shared cfqq will be splitted */ |
416 | CFQ_CFQQ_FLAG_deep, /* sync cfqq experienced large depth */ |
417 | CFQ_CFQQ_FLAG_wait_busy, /* Waiting for next request */ |
418 | }; |
419 | |
420 | #define CFQ_CFQQ_FNS(name) \ |
421 | static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \ |
422 | { \ |
423 | (cfqq)->flags |= (1 << CFQ_CFQQ_FLAG_##name); \ |
424 | } \ |
425 | static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \ |
426 | { \ |
427 | (cfqq)->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \ |
428 | } \ |
429 | static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \ |
430 | { \ |
431 | return ((cfqq)->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \ |
432 | } |
433 | |
434 | CFQ_CFQQ_FNS(on_rr); |
435 | CFQ_CFQQ_FNS(wait_request); |
436 | CFQ_CFQQ_FNS(must_dispatch); |
437 | CFQ_CFQQ_FNS(must_alloc_slice); |
438 | CFQ_CFQQ_FNS(fifo_expire); |
439 | CFQ_CFQQ_FNS(idle_window); |
440 | CFQ_CFQQ_FNS(prio_changed); |
441 | CFQ_CFQQ_FNS(slice_new); |
442 | CFQ_CFQQ_FNS(sync); |
443 | CFQ_CFQQ_FNS(coop); |
444 | CFQ_CFQQ_FNS(split_coop); |
445 | CFQ_CFQQ_FNS(deep); |
446 | CFQ_CFQQ_FNS(wait_busy); |
447 | #undef CFQ_CFQQ_FNS |
448 | |
449 | static inline struct cfq_group *pd_to_cfqg(struct blkg_policy_data *pd) |
450 | { |
451 | return pd ? container_of(pd, struct cfq_group, pd) : NULL; |
452 | } |
453 | |
454 | static inline struct blkcg_gq *cfqg_to_blkg(struct cfq_group *cfqg) |
455 | { |
456 | return pd_to_blkg(&cfqg->pd); |
457 | } |
458 | |
459 | #if defined(CONFIG_CFQ_GROUP_IOSCHED) && defined(CONFIG_DEBUG_BLK_CGROUP) |
460 | |
461 | /* cfqg stats flags */ |
462 | enum cfqg_stats_flags { |
463 | CFQG_stats_waiting = 0, |
464 | CFQG_stats_idling, |
465 | CFQG_stats_empty, |
466 | }; |
467 | |
468 | #define CFQG_FLAG_FNS(name) \ |
469 | static inline void cfqg_stats_mark_##name(struct cfqg_stats *stats) \ |
470 | { \ |
471 | stats->flags |= (1 << CFQG_stats_##name); \ |
472 | } \ |
473 | static inline void cfqg_stats_clear_##name(struct cfqg_stats *stats) \ |
474 | { \ |
475 | stats->flags &= ~(1 << CFQG_stats_##name); \ |
476 | } \ |
477 | static inline int cfqg_stats_##name(struct cfqg_stats *stats) \ |
478 | { \ |
479 | return (stats->flags & (1 << CFQG_stats_##name)) != 0; \ |
480 | } \ |
481 | |
482 | CFQG_FLAG_FNS(waiting) |
483 | CFQG_FLAG_FNS(idling) |
484 | CFQG_FLAG_FNS(empty) |
485 | #undef CFQG_FLAG_FNS |
486 | |
487 | /* This should be called with the queue_lock held. */ |
488 | static void cfqg_stats_update_group_wait_time(struct cfqg_stats *stats) |
489 | { |
490 | unsigned long long now; |
491 | |
492 | if (!cfqg_stats_waiting(stats)) |
493 | return; |
494 | |
495 | now = sched_clock(); |
496 | if (time_after64(now, stats->start_group_wait_time)) |
497 | blkg_stat_add(&stats->group_wait_time, |
498 | now - stats->start_group_wait_time); |
499 | cfqg_stats_clear_waiting(stats); |
500 | } |
501 | |
502 | /* This should be called with the queue_lock held. */ |
503 | static void cfqg_stats_set_start_group_wait_time(struct cfq_group *cfqg, |
504 | struct cfq_group *curr_cfqg) |
505 | { |
506 | struct cfqg_stats *stats = &cfqg->stats; |
507 | |
508 | if (cfqg_stats_waiting(stats)) |
509 | return; |
510 | if (cfqg == curr_cfqg) |
511 | return; |
512 | stats->start_group_wait_time = sched_clock(); |
513 | cfqg_stats_mark_waiting(stats); |
514 | } |
515 | |
516 | /* This should be called with the queue_lock held. */ |
517 | static void cfqg_stats_end_empty_time(struct cfqg_stats *stats) |
518 | { |
519 | unsigned long long now; |
520 | |
521 | if (!cfqg_stats_empty(stats)) |
522 | return; |
523 | |
524 | now = sched_clock(); |
525 | if (time_after64(now, stats->start_empty_time)) |
526 | blkg_stat_add(&stats->empty_time, |
527 | now - stats->start_empty_time); |
528 | cfqg_stats_clear_empty(stats); |
529 | } |
530 | |
531 | static void cfqg_stats_update_dequeue(struct cfq_group *cfqg) |
532 | { |
533 | blkg_stat_add(&cfqg->stats.dequeue, 1); |
534 | } |
535 | |
536 | static void cfqg_stats_set_start_empty_time(struct cfq_group *cfqg) |
537 | { |
538 | struct cfqg_stats *stats = &cfqg->stats; |
539 | |
540 | if (blkg_rwstat_total(&stats->queued)) |
541 | return; |
542 | |
543 | /* |
544 | * group is already marked empty. This can happen if cfqq got new |
545 | * request in parent group and moved to this group while being added |
546 | * to service tree. Just ignore the event and move on. |
547 | */ |
548 | if (cfqg_stats_empty(stats)) |
549 | return; |
550 | |
551 | stats->start_empty_time = sched_clock(); |
552 | cfqg_stats_mark_empty(stats); |
553 | } |
554 | |
555 | static void cfqg_stats_update_idle_time(struct cfq_group *cfqg) |
556 | { |
557 | struct cfqg_stats *stats = &cfqg->stats; |
558 | |
559 | if (cfqg_stats_idling(stats)) { |
560 | unsigned long long now = sched_clock(); |
561 | |
562 | if (time_after64(now, stats->start_idle_time)) |
563 | blkg_stat_add(&stats->idle_time, |
564 | now - stats->start_idle_time); |
565 | cfqg_stats_clear_idling(stats); |
566 | } |
567 | } |
568 | |
569 | static void cfqg_stats_set_start_idle_time(struct cfq_group *cfqg) |
570 | { |
571 | struct cfqg_stats *stats = &cfqg->stats; |
572 | |
573 | BUG_ON(cfqg_stats_idling(stats)); |
574 | |
575 | stats->start_idle_time = sched_clock(); |
576 | cfqg_stats_mark_idling(stats); |
577 | } |
578 | |
579 | static void cfqg_stats_update_avg_queue_size(struct cfq_group *cfqg) |
580 | { |
581 | struct cfqg_stats *stats = &cfqg->stats; |
582 | |
583 | blkg_stat_add(&stats->avg_queue_size_sum, |
584 | blkg_rwstat_total(&stats->queued)); |
585 | blkg_stat_add(&stats->avg_queue_size_samples, 1); |
586 | cfqg_stats_update_group_wait_time(stats); |
587 | } |
588 | |
589 | #else /* CONFIG_CFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */ |
590 | |
591 | static inline void cfqg_stats_set_start_group_wait_time(struct cfq_group *cfqg, struct cfq_group *curr_cfqg) { } |
592 | static inline void cfqg_stats_end_empty_time(struct cfqg_stats *stats) { } |
593 | static inline void cfqg_stats_update_dequeue(struct cfq_group *cfqg) { } |
594 | static inline void cfqg_stats_set_start_empty_time(struct cfq_group *cfqg) { } |
595 | static inline void cfqg_stats_update_idle_time(struct cfq_group *cfqg) { } |
596 | static inline void cfqg_stats_set_start_idle_time(struct cfq_group *cfqg) { } |
597 | static inline void cfqg_stats_update_avg_queue_size(struct cfq_group *cfqg) { } |
598 | |
599 | #endif /* CONFIG_CFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */ |
600 | |
601 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
602 | |
603 | static struct blkcg_policy blkcg_policy_cfq; |
604 | |
605 | static inline struct cfq_group *blkg_to_cfqg(struct blkcg_gq *blkg) |
606 | { |
607 | return pd_to_cfqg(blkg_to_pd(blkg, &blkcg_policy_cfq)); |
608 | } |
609 | |
610 | static inline struct cfq_group *cfqg_parent(struct cfq_group *cfqg) |
611 | { |
612 | struct blkcg_gq *pblkg = cfqg_to_blkg(cfqg)->parent; |
613 | |
614 | return pblkg ? blkg_to_cfqg(pblkg) : NULL; |
615 | } |
616 | |
617 | static inline void cfqg_get(struct cfq_group *cfqg) |
618 | { |
619 | return blkg_get(cfqg_to_blkg(cfqg)); |
620 | } |
621 | |
622 | static inline void cfqg_put(struct cfq_group *cfqg) |
623 | { |
624 | return blkg_put(cfqg_to_blkg(cfqg)); |
625 | } |
626 | |
627 | #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) do { \ |
628 | char __pbuf[128]; \ |
629 | \ |
630 | blkg_path(cfqg_to_blkg((cfqq)->cfqg), __pbuf, sizeof(__pbuf)); \ |
631 | blk_add_trace_msg((cfqd)->queue, "cfq%d%c%c %s " fmt, (cfqq)->pid, \ |
632 | cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \ |
633 | cfqq_type((cfqq)) == SYNC_NOIDLE_WORKLOAD ? 'N' : ' ',\ |
634 | __pbuf, ##args); \ |
635 | } while (0) |
636 | |
637 | #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) do { \ |
638 | char __pbuf[128]; \ |
639 | \ |
640 | blkg_path(cfqg_to_blkg(cfqg), __pbuf, sizeof(__pbuf)); \ |
641 | blk_add_trace_msg((cfqd)->queue, "%s " fmt, __pbuf, ##args); \ |
642 | } while (0) |
643 | |
644 | static inline void cfqg_stats_update_io_add(struct cfq_group *cfqg, |
645 | struct cfq_group *curr_cfqg, int rw) |
646 | { |
647 | blkg_rwstat_add(&cfqg->stats.queued, rw, 1); |
648 | cfqg_stats_end_empty_time(&cfqg->stats); |
649 | cfqg_stats_set_start_group_wait_time(cfqg, curr_cfqg); |
650 | } |
651 | |
652 | static inline void cfqg_stats_update_timeslice_used(struct cfq_group *cfqg, |
653 | unsigned long time, unsigned long unaccounted_time) |
654 | { |
655 | blkg_stat_add(&cfqg->stats.time, time); |
656 | #ifdef CONFIG_DEBUG_BLK_CGROUP |
657 | blkg_stat_add(&cfqg->stats.unaccounted_time, unaccounted_time); |
658 | #endif |
659 | } |
660 | |
661 | static inline void cfqg_stats_update_io_remove(struct cfq_group *cfqg, int rw) |
662 | { |
663 | blkg_rwstat_add(&cfqg->stats.queued, rw, -1); |
664 | } |
665 | |
666 | static inline void cfqg_stats_update_io_merged(struct cfq_group *cfqg, int rw) |
667 | { |
668 | blkg_rwstat_add(&cfqg->stats.merged, rw, 1); |
669 | } |
670 | |
671 | static inline void cfqg_stats_update_dispatch(struct cfq_group *cfqg, |
672 | uint64_t bytes, int rw) |
673 | { |
674 | blkg_stat_add(&cfqg->stats.sectors, bytes >> 9); |
675 | blkg_rwstat_add(&cfqg->stats.serviced, rw, 1); |
676 | blkg_rwstat_add(&cfqg->stats.service_bytes, rw, bytes); |
677 | } |
678 | |
679 | static inline void cfqg_stats_update_completion(struct cfq_group *cfqg, |
680 | uint64_t start_time, uint64_t io_start_time, int rw) |
681 | { |
682 | struct cfqg_stats *stats = &cfqg->stats; |
683 | unsigned long long now = sched_clock(); |
684 | |
685 | if (time_after64(now, io_start_time)) |
686 | blkg_rwstat_add(&stats->service_time, rw, now - io_start_time); |
687 | if (time_after64(io_start_time, start_time)) |
688 | blkg_rwstat_add(&stats->wait_time, rw, |
689 | io_start_time - start_time); |
690 | } |
691 | |
692 | /* @stats = 0 */ |
693 | static void cfqg_stats_reset(struct cfqg_stats *stats) |
694 | { |
695 | /* queued stats shouldn't be cleared */ |
696 | blkg_rwstat_reset(&stats->service_bytes); |
697 | blkg_rwstat_reset(&stats->serviced); |
698 | blkg_rwstat_reset(&stats->merged); |
699 | blkg_rwstat_reset(&stats->service_time); |
700 | blkg_rwstat_reset(&stats->wait_time); |
701 | blkg_stat_reset(&stats->time); |
702 | #ifdef CONFIG_DEBUG_BLK_CGROUP |
703 | blkg_stat_reset(&stats->unaccounted_time); |
704 | blkg_stat_reset(&stats->avg_queue_size_sum); |
705 | blkg_stat_reset(&stats->avg_queue_size_samples); |
706 | blkg_stat_reset(&stats->dequeue); |
707 | blkg_stat_reset(&stats->group_wait_time); |
708 | blkg_stat_reset(&stats->idle_time); |
709 | blkg_stat_reset(&stats->empty_time); |
710 | #endif |
711 | } |
712 | |
713 | /* @to += @from */ |
714 | static void cfqg_stats_merge(struct cfqg_stats *to, struct cfqg_stats *from) |
715 | { |
716 | /* queued stats shouldn't be cleared */ |
717 | blkg_rwstat_merge(&to->service_bytes, &from->service_bytes); |
718 | blkg_rwstat_merge(&to->serviced, &from->serviced); |
719 | blkg_rwstat_merge(&to->merged, &from->merged); |
720 | blkg_rwstat_merge(&to->service_time, &from->service_time); |
721 | blkg_rwstat_merge(&to->wait_time, &from->wait_time); |
722 | blkg_stat_merge(&from->time, &from->time); |
723 | #ifdef CONFIG_DEBUG_BLK_CGROUP |
724 | blkg_stat_merge(&to->unaccounted_time, &from->unaccounted_time); |
725 | blkg_stat_merge(&to->avg_queue_size_sum, &from->avg_queue_size_sum); |
726 | blkg_stat_merge(&to->avg_queue_size_samples, &from->avg_queue_size_samples); |
727 | blkg_stat_merge(&to->dequeue, &from->dequeue); |
728 | blkg_stat_merge(&to->group_wait_time, &from->group_wait_time); |
729 | blkg_stat_merge(&to->idle_time, &from->idle_time); |
730 | blkg_stat_merge(&to->empty_time, &from->empty_time); |
731 | #endif |
732 | } |
733 | |
734 | /* |
735 | * Transfer @cfqg's stats to its parent's dead_stats so that the ancestors' |
736 | * recursive stats can still account for the amount used by this cfqg after |
737 | * it's gone. |
738 | */ |
739 | static void cfqg_stats_xfer_dead(struct cfq_group *cfqg) |
740 | { |
741 | struct cfq_group *parent = cfqg_parent(cfqg); |
742 | |
743 | lockdep_assert_held(cfqg_to_blkg(cfqg)->q->queue_lock); |
744 | |
745 | if (unlikely(!parent)) |
746 | return; |
747 | |
748 | cfqg_stats_merge(&parent->dead_stats, &cfqg->stats); |
749 | cfqg_stats_merge(&parent->dead_stats, &cfqg->dead_stats); |
750 | cfqg_stats_reset(&cfqg->stats); |
751 | cfqg_stats_reset(&cfqg->dead_stats); |
752 | } |
753 | |
754 | #else /* CONFIG_CFQ_GROUP_IOSCHED */ |
755 | |
756 | static inline struct cfq_group *cfqg_parent(struct cfq_group *cfqg) { return NULL; } |
757 | static inline void cfqg_get(struct cfq_group *cfqg) { } |
758 | static inline void cfqg_put(struct cfq_group *cfqg) { } |
759 | |
760 | #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \ |
761 | blk_add_trace_msg((cfqd)->queue, "cfq%d%c%c " fmt, (cfqq)->pid, \ |
762 | cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \ |
763 | cfqq_type((cfqq)) == SYNC_NOIDLE_WORKLOAD ? 'N' : ' ',\ |
764 | ##args) |
765 | #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) do {} while (0) |
766 | |
767 | static inline void cfqg_stats_update_io_add(struct cfq_group *cfqg, |
768 | struct cfq_group *curr_cfqg, int rw) { } |
769 | static inline void cfqg_stats_update_timeslice_used(struct cfq_group *cfqg, |
770 | unsigned long time, unsigned long unaccounted_time) { } |
771 | static inline void cfqg_stats_update_io_remove(struct cfq_group *cfqg, int rw) { } |
772 | static inline void cfqg_stats_update_io_merged(struct cfq_group *cfqg, int rw) { } |
773 | static inline void cfqg_stats_update_dispatch(struct cfq_group *cfqg, |
774 | uint64_t bytes, int rw) { } |
775 | static inline void cfqg_stats_update_completion(struct cfq_group *cfqg, |
776 | uint64_t start_time, uint64_t io_start_time, int rw) { } |
777 | |
778 | #endif /* CONFIG_CFQ_GROUP_IOSCHED */ |
779 | |
780 | #define cfq_log(cfqd, fmt, args...) \ |
781 | blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args) |
782 | |
783 | /* Traverses through cfq group service trees */ |
784 | #define for_each_cfqg_st(cfqg, i, j, st) \ |
785 | for (i = 0; i <= IDLE_WORKLOAD; i++) \ |
786 | for (j = 0, st = i < IDLE_WORKLOAD ? &cfqg->service_trees[i][j]\ |
787 | : &cfqg->service_tree_idle; \ |
788 | (i < IDLE_WORKLOAD && j <= SYNC_WORKLOAD) || \ |
789 | (i == IDLE_WORKLOAD && j == 0); \ |
790 | j++, st = i < IDLE_WORKLOAD ? \ |
791 | &cfqg->service_trees[i][j]: NULL) \ |
792 | |
793 | static inline bool cfq_io_thinktime_big(struct cfq_data *cfqd, |
794 | struct cfq_ttime *ttime, bool group_idle) |
795 | { |
796 | unsigned long slice; |
797 | if (!sample_valid(ttime->ttime_samples)) |
798 | return false; |
799 | if (group_idle) |
800 | slice = cfqd->cfq_group_idle; |
801 | else |
802 | slice = cfqd->cfq_slice_idle; |
803 | return ttime->ttime_mean > slice; |
804 | } |
805 | |
806 | static inline bool iops_mode(struct cfq_data *cfqd) |
807 | { |
808 | /* |
809 | * If we are not idling on queues and it is a NCQ drive, parallel |
810 | * execution of requests is on and measuring time is not possible |
811 | * in most of the cases until and unless we drive shallower queue |
812 | * depths and that becomes a performance bottleneck. In such cases |
813 | * switch to start providing fairness in terms of number of IOs. |
814 | */ |
815 | if (!cfqd->cfq_slice_idle && cfqd->hw_tag) |
816 | return true; |
817 | else |
818 | return false; |
819 | } |
820 | |
821 | static inline enum wl_class_t cfqq_class(struct cfq_queue *cfqq) |
822 | { |
823 | if (cfq_class_idle(cfqq)) |
824 | return IDLE_WORKLOAD; |
825 | if (cfq_class_rt(cfqq)) |
826 | return RT_WORKLOAD; |
827 | return BE_WORKLOAD; |
828 | } |
829 | |
830 | |
831 | static enum wl_type_t cfqq_type(struct cfq_queue *cfqq) |
832 | { |
833 | if (!cfq_cfqq_sync(cfqq)) |
834 | return ASYNC_WORKLOAD; |
835 | if (!cfq_cfqq_idle_window(cfqq)) |
836 | return SYNC_NOIDLE_WORKLOAD; |
837 | return SYNC_WORKLOAD; |
838 | } |
839 | |
840 | static inline int cfq_group_busy_queues_wl(enum wl_class_t wl_class, |
841 | struct cfq_data *cfqd, |
842 | struct cfq_group *cfqg) |
843 | { |
844 | if (wl_class == IDLE_WORKLOAD) |
845 | return cfqg->service_tree_idle.count; |
846 | |
847 | return cfqg->service_trees[wl_class][ASYNC_WORKLOAD].count + |
848 | cfqg->service_trees[wl_class][SYNC_NOIDLE_WORKLOAD].count + |
849 | cfqg->service_trees[wl_class][SYNC_WORKLOAD].count; |
850 | } |
851 | |
852 | static inline int cfqg_busy_async_queues(struct cfq_data *cfqd, |
853 | struct cfq_group *cfqg) |
854 | { |
855 | return cfqg->service_trees[RT_WORKLOAD][ASYNC_WORKLOAD].count + |
856 | cfqg->service_trees[BE_WORKLOAD][ASYNC_WORKLOAD].count; |
857 | } |
858 | |
859 | static void cfq_dispatch_insert(struct request_queue *, struct request *); |
860 | static struct cfq_queue *cfq_get_queue(struct cfq_data *cfqd, bool is_sync, |
861 | struct cfq_io_cq *cic, struct bio *bio, |
862 | gfp_t gfp_mask); |
863 | |
864 | static inline struct cfq_io_cq *icq_to_cic(struct io_cq *icq) |
865 | { |
866 | /* cic->icq is the first member, %NULL will convert to %NULL */ |
867 | return container_of(icq, struct cfq_io_cq, icq); |
868 | } |
869 | |
870 | static inline struct cfq_io_cq *cfq_cic_lookup(struct cfq_data *cfqd, |
871 | struct io_context *ioc) |
872 | { |
873 | if (ioc) |
874 | return icq_to_cic(ioc_lookup_icq(ioc, cfqd->queue)); |
875 | return NULL; |
876 | } |
877 | |
878 | static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_cq *cic, bool is_sync) |
879 | { |
880 | return cic->cfqq[is_sync]; |
881 | } |
882 | |
883 | static inline void cic_set_cfqq(struct cfq_io_cq *cic, struct cfq_queue *cfqq, |
884 | bool is_sync) |
885 | { |
886 | cic->cfqq[is_sync] = cfqq; |
887 | } |
888 | |
889 | static inline struct cfq_data *cic_to_cfqd(struct cfq_io_cq *cic) |
890 | { |
891 | return cic->icq.q->elevator->elevator_data; |
892 | } |
893 | |
894 | /* |
895 | * We regard a request as SYNC, if it's either a read or has the SYNC bit |
896 | * set (in which case it could also be direct WRITE). |
897 | */ |
898 | static inline bool cfq_bio_sync(struct bio *bio) |
899 | { |
900 | return bio_data_dir(bio) == READ || (bio->bi_rw & REQ_SYNC); |
901 | } |
902 | |
903 | /* |
904 | * scheduler run of queue, if there are requests pending and no one in the |
905 | * driver that will restart queueing |
906 | */ |
907 | static inline void cfq_schedule_dispatch(struct cfq_data *cfqd) |
908 | { |
909 | if (cfqd->busy_queues) { |
910 | cfq_log(cfqd, "schedule dispatch"); |
911 | kblockd_schedule_work(cfqd->queue, &cfqd->unplug_work); |
912 | } |
913 | } |
914 | |
915 | /* |
916 | * Scale schedule slice based on io priority. Use the sync time slice only |
917 | * if a queue is marked sync and has sync io queued. A sync queue with async |
918 | * io only, should not get full sync slice length. |
919 | */ |
920 | static inline int cfq_prio_slice(struct cfq_data *cfqd, bool sync, |
921 | unsigned short prio) |
922 | { |
923 | const int base_slice = cfqd->cfq_slice[sync]; |
924 | |
925 | WARN_ON(prio >= IOPRIO_BE_NR); |
926 | |
927 | return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - prio)); |
928 | } |
929 | |
930 | static inline int |
931 | cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
932 | { |
933 | return cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio); |
934 | } |
935 | |
936 | /** |
937 | * cfqg_scale_charge - scale disk time charge according to cfqg weight |
938 | * @charge: disk time being charged |
939 | * @vfraction: vfraction of the cfqg, fixed point w/ CFQ_SERVICE_SHIFT |
940 | * |
941 | * Scale @charge according to @vfraction, which is in range (0, 1]. The |
942 | * scaling is inversely proportional. |
943 | * |
944 | * scaled = charge / vfraction |
945 | * |
946 | * The result is also in fixed point w/ CFQ_SERVICE_SHIFT. |
947 | */ |
948 | static inline u64 cfqg_scale_charge(unsigned long charge, |
949 | unsigned int vfraction) |
950 | { |
951 | u64 c = charge << CFQ_SERVICE_SHIFT; /* make it fixed point */ |
952 | |
953 | /* charge / vfraction */ |
954 | c <<= CFQ_SERVICE_SHIFT; |
955 | do_div(c, vfraction); |
956 | return c; |
957 | } |
958 | |
959 | static inline u64 max_vdisktime(u64 min_vdisktime, u64 vdisktime) |
960 | { |
961 | s64 delta = (s64)(vdisktime - min_vdisktime); |
962 | if (delta > 0) |
963 | min_vdisktime = vdisktime; |
964 | |
965 | return min_vdisktime; |
966 | } |
967 | |
968 | static inline u64 min_vdisktime(u64 min_vdisktime, u64 vdisktime) |
969 | { |
970 | s64 delta = (s64)(vdisktime - min_vdisktime); |
971 | if (delta < 0) |
972 | min_vdisktime = vdisktime; |
973 | |
974 | return min_vdisktime; |
975 | } |
976 | |
977 | static void update_min_vdisktime(struct cfq_rb_root *st) |
978 | { |
979 | struct cfq_group *cfqg; |
980 | |
981 | if (st->left) { |
982 | cfqg = rb_entry_cfqg(st->left); |
983 | st->min_vdisktime = max_vdisktime(st->min_vdisktime, |
984 | cfqg->vdisktime); |
985 | } |
986 | } |
987 | |
988 | /* |
989 | * get averaged number of queues of RT/BE priority. |
990 | * average is updated, with a formula that gives more weight to higher numbers, |
991 | * to quickly follows sudden increases and decrease slowly |
992 | */ |
993 | |
994 | static inline unsigned cfq_group_get_avg_queues(struct cfq_data *cfqd, |
995 | struct cfq_group *cfqg, bool rt) |
996 | { |
997 | unsigned min_q, max_q; |
998 | unsigned mult = cfq_hist_divisor - 1; |
999 | unsigned round = cfq_hist_divisor / 2; |
1000 | unsigned busy = cfq_group_busy_queues_wl(rt, cfqd, cfqg); |
1001 | |
1002 | min_q = min(cfqg->busy_queues_avg[rt], busy); |
1003 | max_q = max(cfqg->busy_queues_avg[rt], busy); |
1004 | cfqg->busy_queues_avg[rt] = (mult * max_q + min_q + round) / |
1005 | cfq_hist_divisor; |
1006 | return cfqg->busy_queues_avg[rt]; |
1007 | } |
1008 | |
1009 | static inline unsigned |
1010 | cfq_group_slice(struct cfq_data *cfqd, struct cfq_group *cfqg) |
1011 | { |
1012 | return cfqd->cfq_target_latency * cfqg->vfraction >> CFQ_SERVICE_SHIFT; |
1013 | } |
1014 | |
1015 | static inline unsigned |
1016 | cfq_scaled_cfqq_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1017 | { |
1018 | unsigned slice = cfq_prio_to_slice(cfqd, cfqq); |
1019 | if (cfqd->cfq_latency) { |
1020 | /* |
1021 | * interested queues (we consider only the ones with the same |
1022 | * priority class in the cfq group) |
1023 | */ |
1024 | unsigned iq = cfq_group_get_avg_queues(cfqd, cfqq->cfqg, |
1025 | cfq_class_rt(cfqq)); |
1026 | unsigned sync_slice = cfqd->cfq_slice[1]; |
1027 | unsigned expect_latency = sync_slice * iq; |
1028 | unsigned group_slice = cfq_group_slice(cfqd, cfqq->cfqg); |
1029 | |
1030 | if (expect_latency > group_slice) { |
1031 | unsigned base_low_slice = 2 * cfqd->cfq_slice_idle; |
1032 | /* scale low_slice according to IO priority |
1033 | * and sync vs async */ |
1034 | unsigned low_slice = |
1035 | min(slice, base_low_slice * slice / sync_slice); |
1036 | /* the adapted slice value is scaled to fit all iqs |
1037 | * into the target latency */ |
1038 | slice = max(slice * group_slice / expect_latency, |
1039 | low_slice); |
1040 | } |
1041 | } |
1042 | return slice; |
1043 | } |
1044 | |
1045 | static inline void |
1046 | cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1047 | { |
1048 | unsigned slice = cfq_scaled_cfqq_slice(cfqd, cfqq); |
1049 | |
1050 | cfqq->slice_start = jiffies; |
1051 | cfqq->slice_end = jiffies + slice; |
1052 | cfqq->allocated_slice = slice; |
1053 | cfq_log_cfqq(cfqd, cfqq, "set_slice=%lu", cfqq->slice_end - jiffies); |
1054 | } |
1055 | |
1056 | /* |
1057 | * We need to wrap this check in cfq_cfqq_slice_new(), since ->slice_end |
1058 | * isn't valid until the first request from the dispatch is activated |
1059 | * and the slice time set. |
1060 | */ |
1061 | static inline bool cfq_slice_used(struct cfq_queue *cfqq) |
1062 | { |
1063 | if (cfq_cfqq_slice_new(cfqq)) |
1064 | return false; |
1065 | if (time_before(jiffies, cfqq->slice_end)) |
1066 | return false; |
1067 | |
1068 | return true; |
1069 | } |
1070 | |
1071 | /* |
1072 | * Lifted from AS - choose which of rq1 and rq2 that is best served now. |
1073 | * We choose the request that is closest to the head right now. Distance |
1074 | * behind the head is penalized and only allowed to a certain extent. |
1075 | */ |
1076 | static struct request * |
1077 | cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2, sector_t last) |
1078 | { |
1079 | sector_t s1, s2, d1 = 0, d2 = 0; |
1080 | unsigned long back_max; |
1081 | #define CFQ_RQ1_WRAP 0x01 /* request 1 wraps */ |
1082 | #define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */ |
1083 | unsigned wrap = 0; /* bit mask: requests behind the disk head? */ |
1084 | |
1085 | if (rq1 == NULL || rq1 == rq2) |
1086 | return rq2; |
1087 | if (rq2 == NULL) |
1088 | return rq1; |
1089 | |
1090 | if (rq_is_sync(rq1) != rq_is_sync(rq2)) |
1091 | return rq_is_sync(rq1) ? rq1 : rq2; |
1092 | |
1093 | if ((rq1->cmd_flags ^ rq2->cmd_flags) & REQ_PRIO) |
1094 | return rq1->cmd_flags & REQ_PRIO ? rq1 : rq2; |
1095 | |
1096 | s1 = blk_rq_pos(rq1); |
1097 | s2 = blk_rq_pos(rq2); |
1098 | |
1099 | /* |
1100 | * by definition, 1KiB is 2 sectors |
1101 | */ |
1102 | back_max = cfqd->cfq_back_max * 2; |
1103 | |
1104 | /* |
1105 | * Strict one way elevator _except_ in the case where we allow |
1106 | * short backward seeks which are biased as twice the cost of a |
1107 | * similar forward seek. |
1108 | */ |
1109 | if (s1 >= last) |
1110 | d1 = s1 - last; |
1111 | else if (s1 + back_max >= last) |
1112 | d1 = (last - s1) * cfqd->cfq_back_penalty; |
1113 | else |
1114 | wrap |= CFQ_RQ1_WRAP; |
1115 | |
1116 | if (s2 >= last) |
1117 | d2 = s2 - last; |
1118 | else if (s2 + back_max >= last) |
1119 | d2 = (last - s2) * cfqd->cfq_back_penalty; |
1120 | else |
1121 | wrap |= CFQ_RQ2_WRAP; |
1122 | |
1123 | /* Found required data */ |
1124 | |
1125 | /* |
1126 | * By doing switch() on the bit mask "wrap" we avoid having to |
1127 | * check two variables for all permutations: --> faster! |
1128 | */ |
1129 | switch (wrap) { |
1130 | case 0: /* common case for CFQ: rq1 and rq2 not wrapped */ |
1131 | if (d1 < d2) |
1132 | return rq1; |
1133 | else if (d2 < d1) |
1134 | return rq2; |
1135 | else { |
1136 | if (s1 >= s2) |
1137 | return rq1; |
1138 | else |
1139 | return rq2; |
1140 | } |
1141 | |
1142 | case CFQ_RQ2_WRAP: |
1143 | return rq1; |
1144 | case CFQ_RQ1_WRAP: |
1145 | return rq2; |
1146 | case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both rqs wrapped */ |
1147 | default: |
1148 | /* |
1149 | * Since both rqs are wrapped, |
1150 | * start with the one that's further behind head |
1151 | * (--> only *one* back seek required), |
1152 | * since back seek takes more time than forward. |
1153 | */ |
1154 | if (s1 <= s2) |
1155 | return rq1; |
1156 | else |
1157 | return rq2; |
1158 | } |
1159 | } |
1160 | |
1161 | /* |
1162 | * The below is leftmost cache rbtree addon |
1163 | */ |
1164 | static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root) |
1165 | { |
1166 | /* Service tree is empty */ |
1167 | if (!root->count) |
1168 | return NULL; |
1169 | |
1170 | if (!root->left) |
1171 | root->left = rb_first(&root->rb); |
1172 | |
1173 | if (root->left) |
1174 | return rb_entry(root->left, struct cfq_queue, rb_node); |
1175 | |
1176 | return NULL; |
1177 | } |
1178 | |
1179 | static struct cfq_group *cfq_rb_first_group(struct cfq_rb_root *root) |
1180 | { |
1181 | if (!root->left) |
1182 | root->left = rb_first(&root->rb); |
1183 | |
1184 | if (root->left) |
1185 | return rb_entry_cfqg(root->left); |
1186 | |
1187 | return NULL; |
1188 | } |
1189 | |
1190 | static void rb_erase_init(struct rb_node *n, struct rb_root *root) |
1191 | { |
1192 | rb_erase(n, root); |
1193 | RB_CLEAR_NODE(n); |
1194 | } |
1195 | |
1196 | static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root) |
1197 | { |
1198 | if (root->left == n) |
1199 | root->left = NULL; |
1200 | rb_erase_init(n, &root->rb); |
1201 | --root->count; |
1202 | } |
1203 | |
1204 | /* |
1205 | * would be nice to take fifo expire time into account as well |
1206 | */ |
1207 | static struct request * |
1208 | cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
1209 | struct request *last) |
1210 | { |
1211 | struct rb_node *rbnext = rb_next(&last->rb_node); |
1212 | struct rb_node *rbprev = rb_prev(&last->rb_node); |
1213 | struct request *next = NULL, *prev = NULL; |
1214 | |
1215 | BUG_ON(RB_EMPTY_NODE(&last->rb_node)); |
1216 | |
1217 | if (rbprev) |
1218 | prev = rb_entry_rq(rbprev); |
1219 | |
1220 | if (rbnext) |
1221 | next = rb_entry_rq(rbnext); |
1222 | else { |
1223 | rbnext = rb_first(&cfqq->sort_list); |
1224 | if (rbnext && rbnext != &last->rb_node) |
1225 | next = rb_entry_rq(rbnext); |
1226 | } |
1227 | |
1228 | return cfq_choose_req(cfqd, next, prev, blk_rq_pos(last)); |
1229 | } |
1230 | |
1231 | static unsigned long cfq_slice_offset(struct cfq_data *cfqd, |
1232 | struct cfq_queue *cfqq) |
1233 | { |
1234 | /* |
1235 | * just an approximation, should be ok. |
1236 | */ |
1237 | return (cfqq->cfqg->nr_cfqq - 1) * (cfq_prio_slice(cfqd, 1, 0) - |
1238 | cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio)); |
1239 | } |
1240 | |
1241 | static inline s64 |
1242 | cfqg_key(struct cfq_rb_root *st, struct cfq_group *cfqg) |
1243 | { |
1244 | return cfqg->vdisktime - st->min_vdisktime; |
1245 | } |
1246 | |
1247 | static void |
1248 | __cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg) |
1249 | { |
1250 | struct rb_node **node = &st->rb.rb_node; |
1251 | struct rb_node *parent = NULL; |
1252 | struct cfq_group *__cfqg; |
1253 | s64 key = cfqg_key(st, cfqg); |
1254 | int left = 1; |
1255 | |
1256 | while (*node != NULL) { |
1257 | parent = *node; |
1258 | __cfqg = rb_entry_cfqg(parent); |
1259 | |
1260 | if (key < cfqg_key(st, __cfqg)) |
1261 | node = &parent->rb_left; |
1262 | else { |
1263 | node = &parent->rb_right; |
1264 | left = 0; |
1265 | } |
1266 | } |
1267 | |
1268 | if (left) |
1269 | st->left = &cfqg->rb_node; |
1270 | |
1271 | rb_link_node(&cfqg->rb_node, parent, node); |
1272 | rb_insert_color(&cfqg->rb_node, &st->rb); |
1273 | } |
1274 | |
1275 | static void |
1276 | cfq_update_group_weight(struct cfq_group *cfqg) |
1277 | { |
1278 | BUG_ON(!RB_EMPTY_NODE(&cfqg->rb_node)); |
1279 | |
1280 | if (cfqg->new_weight) { |
1281 | cfqg->weight = cfqg->new_weight; |
1282 | cfqg->new_weight = 0; |
1283 | } |
1284 | |
1285 | if (cfqg->new_leaf_weight) { |
1286 | cfqg->leaf_weight = cfqg->new_leaf_weight; |
1287 | cfqg->new_leaf_weight = 0; |
1288 | } |
1289 | } |
1290 | |
1291 | static void |
1292 | cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg) |
1293 | { |
1294 | unsigned int vfr = 1 << CFQ_SERVICE_SHIFT; /* start with 1 */ |
1295 | struct cfq_group *pos = cfqg; |
1296 | struct cfq_group *parent; |
1297 | bool propagate; |
1298 | |
1299 | /* add to the service tree */ |
1300 | BUG_ON(!RB_EMPTY_NODE(&cfqg->rb_node)); |
1301 | |
1302 | cfq_update_group_weight(cfqg); |
1303 | __cfq_group_service_tree_add(st, cfqg); |
1304 | |
1305 | /* |
1306 | * Activate @cfqg and calculate the portion of vfraction @cfqg is |
1307 | * entitled to. vfraction is calculated by walking the tree |
1308 | * towards the root calculating the fraction it has at each level. |
1309 | * The compounded ratio is how much vfraction @cfqg owns. |
1310 | * |
1311 | * Start with the proportion tasks in this cfqg has against active |
1312 | * children cfqgs - its leaf_weight against children_weight. |
1313 | */ |
1314 | propagate = !pos->nr_active++; |
1315 | pos->children_weight += pos->leaf_weight; |
1316 | vfr = vfr * pos->leaf_weight / pos->children_weight; |
1317 | |
1318 | /* |
1319 | * Compound ->weight walking up the tree. Both activation and |
1320 | * vfraction calculation are done in the same loop. Propagation |
1321 | * stops once an already activated node is met. vfraction |
1322 | * calculation should always continue to the root. |
1323 | */ |
1324 | while ((parent = cfqg_parent(pos))) { |
1325 | if (propagate) { |
1326 | propagate = !parent->nr_active++; |
1327 | parent->children_weight += pos->weight; |
1328 | } |
1329 | vfr = vfr * pos->weight / parent->children_weight; |
1330 | pos = parent; |
1331 | } |
1332 | |
1333 | cfqg->vfraction = max_t(unsigned, vfr, 1); |
1334 | } |
1335 | |
1336 | static void |
1337 | cfq_group_notify_queue_add(struct cfq_data *cfqd, struct cfq_group *cfqg) |
1338 | { |
1339 | struct cfq_rb_root *st = &cfqd->grp_service_tree; |
1340 | struct cfq_group *__cfqg; |
1341 | struct rb_node *n; |
1342 | |
1343 | cfqg->nr_cfqq++; |
1344 | if (!RB_EMPTY_NODE(&cfqg->rb_node)) |
1345 | return; |
1346 | |
1347 | /* |
1348 | * Currently put the group at the end. Later implement something |
1349 | * so that groups get lesser vtime based on their weights, so that |
1350 | * if group does not loose all if it was not continuously backlogged. |
1351 | */ |
1352 | n = rb_last(&st->rb); |
1353 | if (n) { |
1354 | __cfqg = rb_entry_cfqg(n); |
1355 | cfqg->vdisktime = __cfqg->vdisktime + CFQ_IDLE_DELAY; |
1356 | } else |
1357 | cfqg->vdisktime = st->min_vdisktime; |
1358 | cfq_group_service_tree_add(st, cfqg); |
1359 | } |
1360 | |
1361 | static void |
1362 | cfq_group_service_tree_del(struct cfq_rb_root *st, struct cfq_group *cfqg) |
1363 | { |
1364 | struct cfq_group *pos = cfqg; |
1365 | bool propagate; |
1366 | |
1367 | /* |
1368 | * Undo activation from cfq_group_service_tree_add(). Deactivate |
1369 | * @cfqg and propagate deactivation upwards. |
1370 | */ |
1371 | propagate = !--pos->nr_active; |
1372 | pos->children_weight -= pos->leaf_weight; |
1373 | |
1374 | while (propagate) { |
1375 | struct cfq_group *parent = cfqg_parent(pos); |
1376 | |
1377 | /* @pos has 0 nr_active at this point */ |
1378 | WARN_ON_ONCE(pos->children_weight); |
1379 | pos->vfraction = 0; |
1380 | |
1381 | if (!parent) |
1382 | break; |
1383 | |
1384 | propagate = !--parent->nr_active; |
1385 | parent->children_weight -= pos->weight; |
1386 | pos = parent; |
1387 | } |
1388 | |
1389 | /* remove from the service tree */ |
1390 | if (!RB_EMPTY_NODE(&cfqg->rb_node)) |
1391 | cfq_rb_erase(&cfqg->rb_node, st); |
1392 | } |
1393 | |
1394 | static void |
1395 | cfq_group_notify_queue_del(struct cfq_data *cfqd, struct cfq_group *cfqg) |
1396 | { |
1397 | struct cfq_rb_root *st = &cfqd->grp_service_tree; |
1398 | |
1399 | BUG_ON(cfqg->nr_cfqq < 1); |
1400 | cfqg->nr_cfqq--; |
1401 | |
1402 | /* If there are other cfq queues under this group, don't delete it */ |
1403 | if (cfqg->nr_cfqq) |
1404 | return; |
1405 | |
1406 | cfq_log_cfqg(cfqd, cfqg, "del_from_rr group"); |
1407 | cfq_group_service_tree_del(st, cfqg); |
1408 | cfqg->saved_wl_slice = 0; |
1409 | cfqg_stats_update_dequeue(cfqg); |
1410 | } |
1411 | |
1412 | static inline unsigned int cfq_cfqq_slice_usage(struct cfq_queue *cfqq, |
1413 | unsigned int *unaccounted_time) |
1414 | { |
1415 | unsigned int slice_used; |
1416 | |
1417 | /* |
1418 | * Queue got expired before even a single request completed or |
1419 | * got expired immediately after first request completion. |
1420 | */ |
1421 | if (!cfqq->slice_start || cfqq->slice_start == jiffies) { |
1422 | /* |
1423 | * Also charge the seek time incurred to the group, otherwise |
1424 | * if there are mutiple queues in the group, each can dispatch |
1425 | * a single request on seeky media and cause lots of seek time |
1426 | * and group will never know it. |
1427 | */ |
1428 | slice_used = max_t(unsigned, (jiffies - cfqq->dispatch_start), |
1429 | 1); |
1430 | } else { |
1431 | slice_used = jiffies - cfqq->slice_start; |
1432 | if (slice_used > cfqq->allocated_slice) { |
1433 | *unaccounted_time = slice_used - cfqq->allocated_slice; |
1434 | slice_used = cfqq->allocated_slice; |
1435 | } |
1436 | if (time_after(cfqq->slice_start, cfqq->dispatch_start)) |
1437 | *unaccounted_time += cfqq->slice_start - |
1438 | cfqq->dispatch_start; |
1439 | } |
1440 | |
1441 | return slice_used; |
1442 | } |
1443 | |
1444 | static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg, |
1445 | struct cfq_queue *cfqq) |
1446 | { |
1447 | struct cfq_rb_root *st = &cfqd->grp_service_tree; |
1448 | unsigned int used_sl, charge, unaccounted_sl = 0; |
1449 | int nr_sync = cfqg->nr_cfqq - cfqg_busy_async_queues(cfqd, cfqg) |
1450 | - cfqg->service_tree_idle.count; |
1451 | unsigned int vfr; |
1452 | |
1453 | BUG_ON(nr_sync < 0); |
1454 | used_sl = charge = cfq_cfqq_slice_usage(cfqq, &unaccounted_sl); |
1455 | |
1456 | if (iops_mode(cfqd)) |
1457 | charge = cfqq->slice_dispatch; |
1458 | else if (!cfq_cfqq_sync(cfqq) && !nr_sync) |
1459 | charge = cfqq->allocated_slice; |
1460 | |
1461 | /* |
1462 | * Can't update vdisktime while on service tree and cfqg->vfraction |
1463 | * is valid only while on it. Cache vfr, leave the service tree, |
1464 | * update vdisktime and go back on. The re-addition to the tree |
1465 | * will also update the weights as necessary. |
1466 | */ |
1467 | vfr = cfqg->vfraction; |
1468 | cfq_group_service_tree_del(st, cfqg); |
1469 | cfqg->vdisktime += cfqg_scale_charge(charge, vfr); |
1470 | cfq_group_service_tree_add(st, cfqg); |
1471 | |
1472 | /* This group is being expired. Save the context */ |
1473 | if (time_after(cfqd->workload_expires, jiffies)) { |
1474 | cfqg->saved_wl_slice = cfqd->workload_expires |
1475 | - jiffies; |
1476 | cfqg->saved_wl_type = cfqd->serving_wl_type; |
1477 | cfqg->saved_wl_class = cfqd->serving_wl_class; |
1478 | } else |
1479 | cfqg->saved_wl_slice = 0; |
1480 | |
1481 | cfq_log_cfqg(cfqd, cfqg, "served: vt=%llu min_vt=%llu", cfqg->vdisktime, |
1482 | st->min_vdisktime); |
1483 | cfq_log_cfqq(cfqq->cfqd, cfqq, |
1484 | "sl_used=%u disp=%u charge=%u iops=%u sect=%lu", |
1485 | used_sl, cfqq->slice_dispatch, charge, |
1486 | iops_mode(cfqd), cfqq->nr_sectors); |
1487 | cfqg_stats_update_timeslice_used(cfqg, used_sl, unaccounted_sl); |
1488 | cfqg_stats_set_start_empty_time(cfqg); |
1489 | } |
1490 | |
1491 | /** |
1492 | * cfq_init_cfqg_base - initialize base part of a cfq_group |
1493 | * @cfqg: cfq_group to initialize |
1494 | * |
1495 | * Initialize the base part which is used whether %CONFIG_CFQ_GROUP_IOSCHED |
1496 | * is enabled or not. |
1497 | */ |
1498 | static void cfq_init_cfqg_base(struct cfq_group *cfqg) |
1499 | { |
1500 | struct cfq_rb_root *st; |
1501 | int i, j; |
1502 | |
1503 | for_each_cfqg_st(cfqg, i, j, st) |
1504 | *st = CFQ_RB_ROOT; |
1505 | RB_CLEAR_NODE(&cfqg->rb_node); |
1506 | |
1507 | cfqg->ttime.last_end_request = jiffies; |
1508 | } |
1509 | |
1510 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
1511 | static void cfq_pd_init(struct blkcg_gq *blkg) |
1512 | { |
1513 | struct cfq_group *cfqg = blkg_to_cfqg(blkg); |
1514 | |
1515 | cfq_init_cfqg_base(cfqg); |
1516 | cfqg->weight = blkg->blkcg->cfq_weight; |
1517 | cfqg->leaf_weight = blkg->blkcg->cfq_leaf_weight; |
1518 | } |
1519 | |
1520 | static void cfq_pd_offline(struct blkcg_gq *blkg) |
1521 | { |
1522 | /* |
1523 | * @blkg is going offline and will be ignored by |
1524 | * blkg_[rw]stat_recursive_sum(). Transfer stats to the parent so |
1525 | * that they don't get lost. If IOs complete after this point, the |
1526 | * stats for them will be lost. Oh well... |
1527 | */ |
1528 | cfqg_stats_xfer_dead(blkg_to_cfqg(blkg)); |
1529 | } |
1530 | |
1531 | /* offset delta from cfqg->stats to cfqg->dead_stats */ |
1532 | static const int dead_stats_off_delta = offsetof(struct cfq_group, dead_stats) - |
1533 | offsetof(struct cfq_group, stats); |
1534 | |
1535 | /* to be used by recursive prfill, sums live and dead stats recursively */ |
1536 | static u64 cfqg_stat_pd_recursive_sum(struct blkg_policy_data *pd, int off) |
1537 | { |
1538 | u64 sum = 0; |
1539 | |
1540 | sum += blkg_stat_recursive_sum(pd, off); |
1541 | sum += blkg_stat_recursive_sum(pd, off + dead_stats_off_delta); |
1542 | return sum; |
1543 | } |
1544 | |
1545 | /* to be used by recursive prfill, sums live and dead rwstats recursively */ |
1546 | static struct blkg_rwstat cfqg_rwstat_pd_recursive_sum(struct blkg_policy_data *pd, |
1547 | int off) |
1548 | { |
1549 | struct blkg_rwstat a, b; |
1550 | |
1551 | a = blkg_rwstat_recursive_sum(pd, off); |
1552 | b = blkg_rwstat_recursive_sum(pd, off + dead_stats_off_delta); |
1553 | blkg_rwstat_merge(&a, &b); |
1554 | return a; |
1555 | } |
1556 | |
1557 | static void cfq_pd_reset_stats(struct blkcg_gq *blkg) |
1558 | { |
1559 | struct cfq_group *cfqg = blkg_to_cfqg(blkg); |
1560 | |
1561 | cfqg_stats_reset(&cfqg->stats); |
1562 | cfqg_stats_reset(&cfqg->dead_stats); |
1563 | } |
1564 | |
1565 | /* |
1566 | * Search for the cfq group current task belongs to. request_queue lock must |
1567 | * be held. |
1568 | */ |
1569 | static struct cfq_group *cfq_lookup_create_cfqg(struct cfq_data *cfqd, |
1570 | struct blkcg *blkcg) |
1571 | { |
1572 | struct request_queue *q = cfqd->queue; |
1573 | struct cfq_group *cfqg = NULL; |
1574 | |
1575 | /* avoid lookup for the common case where there's no blkcg */ |
1576 | if (blkcg == &blkcg_root) { |
1577 | cfqg = cfqd->root_group; |
1578 | } else { |
1579 | struct blkcg_gq *blkg; |
1580 | |
1581 | blkg = blkg_lookup_create(blkcg, q); |
1582 | if (!IS_ERR(blkg)) |
1583 | cfqg = blkg_to_cfqg(blkg); |
1584 | } |
1585 | |
1586 | return cfqg; |
1587 | } |
1588 | |
1589 | static void cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) |
1590 | { |
1591 | /* Currently, all async queues are mapped to root group */ |
1592 | if (!cfq_cfqq_sync(cfqq)) |
1593 | cfqg = cfqq->cfqd->root_group; |
1594 | |
1595 | cfqq->cfqg = cfqg; |
1596 | /* cfqq reference on cfqg */ |
1597 | cfqg_get(cfqg); |
1598 | } |
1599 | |
1600 | static u64 cfqg_prfill_weight_device(struct seq_file *sf, |
1601 | struct blkg_policy_data *pd, int off) |
1602 | { |
1603 | struct cfq_group *cfqg = pd_to_cfqg(pd); |
1604 | |
1605 | if (!cfqg->dev_weight) |
1606 | return 0; |
1607 | return __blkg_prfill_u64(sf, pd, cfqg->dev_weight); |
1608 | } |
1609 | |
1610 | static int cfqg_print_weight_device(struct cgroup *cgrp, struct cftype *cft, |
1611 | struct seq_file *sf) |
1612 | { |
1613 | blkcg_print_blkgs(sf, cgroup_to_blkcg(cgrp), |
1614 | cfqg_prfill_weight_device, &blkcg_policy_cfq, 0, |
1615 | false); |
1616 | return 0; |
1617 | } |
1618 | |
1619 | static u64 cfqg_prfill_leaf_weight_device(struct seq_file *sf, |
1620 | struct blkg_policy_data *pd, int off) |
1621 | { |
1622 | struct cfq_group *cfqg = pd_to_cfqg(pd); |
1623 | |
1624 | if (!cfqg->dev_leaf_weight) |
1625 | return 0; |
1626 | return __blkg_prfill_u64(sf, pd, cfqg->dev_leaf_weight); |
1627 | } |
1628 | |
1629 | static int cfqg_print_leaf_weight_device(struct cgroup *cgrp, |
1630 | struct cftype *cft, |
1631 | struct seq_file *sf) |
1632 | { |
1633 | blkcg_print_blkgs(sf, cgroup_to_blkcg(cgrp), |
1634 | cfqg_prfill_leaf_weight_device, &blkcg_policy_cfq, 0, |
1635 | false); |
1636 | return 0; |
1637 | } |
1638 | |
1639 | static int cfq_print_weight(struct cgroup *cgrp, struct cftype *cft, |
1640 | struct seq_file *sf) |
1641 | { |
1642 | seq_printf(sf, "%u\n", cgroup_to_blkcg(cgrp)->cfq_weight); |
1643 | return 0; |
1644 | } |
1645 | |
1646 | static int cfq_print_leaf_weight(struct cgroup *cgrp, struct cftype *cft, |
1647 | struct seq_file *sf) |
1648 | { |
1649 | seq_printf(sf, "%u\n", |
1650 | cgroup_to_blkcg(cgrp)->cfq_leaf_weight); |
1651 | return 0; |
1652 | } |
1653 | |
1654 | static int __cfqg_set_weight_device(struct cgroup *cgrp, struct cftype *cft, |
1655 | const char *buf, bool is_leaf_weight) |
1656 | { |
1657 | struct blkcg *blkcg = cgroup_to_blkcg(cgrp); |
1658 | struct blkg_conf_ctx ctx; |
1659 | struct cfq_group *cfqg; |
1660 | int ret; |
1661 | |
1662 | ret = blkg_conf_prep(blkcg, &blkcg_policy_cfq, buf, &ctx); |
1663 | if (ret) |
1664 | return ret; |
1665 | |
1666 | ret = -EINVAL; |
1667 | cfqg = blkg_to_cfqg(ctx.blkg); |
1668 | if (!ctx.v || (ctx.v >= CFQ_WEIGHT_MIN && ctx.v <= CFQ_WEIGHT_MAX)) { |
1669 | if (!is_leaf_weight) { |
1670 | cfqg->dev_weight = ctx.v; |
1671 | cfqg->new_weight = ctx.v ?: blkcg->cfq_weight; |
1672 | } else { |
1673 | cfqg->dev_leaf_weight = ctx.v; |
1674 | cfqg->new_leaf_weight = ctx.v ?: blkcg->cfq_leaf_weight; |
1675 | } |
1676 | ret = 0; |
1677 | } |
1678 | |
1679 | blkg_conf_finish(&ctx); |
1680 | return ret; |
1681 | } |
1682 | |
1683 | static int cfqg_set_weight_device(struct cgroup *cgrp, struct cftype *cft, |
1684 | const char *buf) |
1685 | { |
1686 | return __cfqg_set_weight_device(cgrp, cft, buf, false); |
1687 | } |
1688 | |
1689 | static int cfqg_set_leaf_weight_device(struct cgroup *cgrp, struct cftype *cft, |
1690 | const char *buf) |
1691 | { |
1692 | return __cfqg_set_weight_device(cgrp, cft, buf, true); |
1693 | } |
1694 | |
1695 | static int __cfq_set_weight(struct cgroup *cgrp, struct cftype *cft, u64 val, |
1696 | bool is_leaf_weight) |
1697 | { |
1698 | struct blkcg *blkcg = cgroup_to_blkcg(cgrp); |
1699 | struct blkcg_gq *blkg; |
1700 | |
1701 | if (val < CFQ_WEIGHT_MIN || val > CFQ_WEIGHT_MAX) |
1702 | return -EINVAL; |
1703 | |
1704 | spin_lock_irq(&blkcg->lock); |
1705 | |
1706 | if (!is_leaf_weight) |
1707 | blkcg->cfq_weight = val; |
1708 | else |
1709 | blkcg->cfq_leaf_weight = val; |
1710 | |
1711 | hlist_for_each_entry(blkg, &blkcg->blkg_list, blkcg_node) { |
1712 | struct cfq_group *cfqg = blkg_to_cfqg(blkg); |
1713 | |
1714 | if (!cfqg) |
1715 | continue; |
1716 | |
1717 | if (!is_leaf_weight) { |
1718 | if (!cfqg->dev_weight) |
1719 | cfqg->new_weight = blkcg->cfq_weight; |
1720 | } else { |
1721 | if (!cfqg->dev_leaf_weight) |
1722 | cfqg->new_leaf_weight = blkcg->cfq_leaf_weight; |
1723 | } |
1724 | } |
1725 | |
1726 | spin_unlock_irq(&blkcg->lock); |
1727 | return 0; |
1728 | } |
1729 | |
1730 | static int cfq_set_weight(struct cgroup *cgrp, struct cftype *cft, u64 val) |
1731 | { |
1732 | return __cfq_set_weight(cgrp, cft, val, false); |
1733 | } |
1734 | |
1735 | static int cfq_set_leaf_weight(struct cgroup *cgrp, struct cftype *cft, u64 val) |
1736 | { |
1737 | return __cfq_set_weight(cgrp, cft, val, true); |
1738 | } |
1739 | |
1740 | static int cfqg_print_stat(struct cgroup *cgrp, struct cftype *cft, |
1741 | struct seq_file *sf) |
1742 | { |
1743 | struct blkcg *blkcg = cgroup_to_blkcg(cgrp); |
1744 | |
1745 | blkcg_print_blkgs(sf, blkcg, blkg_prfill_stat, &blkcg_policy_cfq, |
1746 | cft->private, false); |
1747 | return 0; |
1748 | } |
1749 | |
1750 | static int cfqg_print_rwstat(struct cgroup *cgrp, struct cftype *cft, |
1751 | struct seq_file *sf) |
1752 | { |
1753 | struct blkcg *blkcg = cgroup_to_blkcg(cgrp); |
1754 | |
1755 | blkcg_print_blkgs(sf, blkcg, blkg_prfill_rwstat, &blkcg_policy_cfq, |
1756 | cft->private, true); |
1757 | return 0; |
1758 | } |
1759 | |
1760 | static u64 cfqg_prfill_stat_recursive(struct seq_file *sf, |
1761 | struct blkg_policy_data *pd, int off) |
1762 | { |
1763 | u64 sum = cfqg_stat_pd_recursive_sum(pd, off); |
1764 | |
1765 | return __blkg_prfill_u64(sf, pd, sum); |
1766 | } |
1767 | |
1768 | static u64 cfqg_prfill_rwstat_recursive(struct seq_file *sf, |
1769 | struct blkg_policy_data *pd, int off) |
1770 | { |
1771 | struct blkg_rwstat sum = cfqg_rwstat_pd_recursive_sum(pd, off); |
1772 | |
1773 | return __blkg_prfill_rwstat(sf, pd, &sum); |
1774 | } |
1775 | |
1776 | static int cfqg_print_stat_recursive(struct cgroup *cgrp, struct cftype *cft, |
1777 | struct seq_file *sf) |
1778 | { |
1779 | struct blkcg *blkcg = cgroup_to_blkcg(cgrp); |
1780 | |
1781 | blkcg_print_blkgs(sf, blkcg, cfqg_prfill_stat_recursive, |
1782 | &blkcg_policy_cfq, cft->private, false); |
1783 | return 0; |
1784 | } |
1785 | |
1786 | static int cfqg_print_rwstat_recursive(struct cgroup *cgrp, struct cftype *cft, |
1787 | struct seq_file *sf) |
1788 | { |
1789 | struct blkcg *blkcg = cgroup_to_blkcg(cgrp); |
1790 | |
1791 | blkcg_print_blkgs(sf, blkcg, cfqg_prfill_rwstat_recursive, |
1792 | &blkcg_policy_cfq, cft->private, true); |
1793 | return 0; |
1794 | } |
1795 | |
1796 | #ifdef CONFIG_DEBUG_BLK_CGROUP |
1797 | static u64 cfqg_prfill_avg_queue_size(struct seq_file *sf, |
1798 | struct blkg_policy_data *pd, int off) |
1799 | { |
1800 | struct cfq_group *cfqg = pd_to_cfqg(pd); |
1801 | u64 samples = blkg_stat_read(&cfqg->stats.avg_queue_size_samples); |
1802 | u64 v = 0; |
1803 | |
1804 | if (samples) { |
1805 | v = blkg_stat_read(&cfqg->stats.avg_queue_size_sum); |
1806 | do_div(v, samples); |
1807 | } |
1808 | __blkg_prfill_u64(sf, pd, v); |
1809 | return 0; |
1810 | } |
1811 | |
1812 | /* print avg_queue_size */ |
1813 | static int cfqg_print_avg_queue_size(struct cgroup *cgrp, struct cftype *cft, |
1814 | struct seq_file *sf) |
1815 | { |
1816 | struct blkcg *blkcg = cgroup_to_blkcg(cgrp); |
1817 | |
1818 | blkcg_print_blkgs(sf, blkcg, cfqg_prfill_avg_queue_size, |
1819 | &blkcg_policy_cfq, 0, false); |
1820 | return 0; |
1821 | } |
1822 | #endif /* CONFIG_DEBUG_BLK_CGROUP */ |
1823 | |
1824 | static struct cftype cfq_blkcg_files[] = { |
1825 | /* on root, weight is mapped to leaf_weight */ |
1826 | { |
1827 | .name = "weight_device", |
1828 | .flags = CFTYPE_ONLY_ON_ROOT, |
1829 | .read_seq_string = cfqg_print_leaf_weight_device, |
1830 | .write_string = cfqg_set_leaf_weight_device, |
1831 | .max_write_len = 256, |
1832 | }, |
1833 | { |
1834 | .name = "weight", |
1835 | .flags = CFTYPE_ONLY_ON_ROOT, |
1836 | .read_seq_string = cfq_print_leaf_weight, |
1837 | .write_u64 = cfq_set_leaf_weight, |
1838 | }, |
1839 | |
1840 | /* no such mapping necessary for !roots */ |
1841 | { |
1842 | .name = "weight_device", |
1843 | .flags = CFTYPE_NOT_ON_ROOT, |
1844 | .read_seq_string = cfqg_print_weight_device, |
1845 | .write_string = cfqg_set_weight_device, |
1846 | .max_write_len = 256, |
1847 | }, |
1848 | { |
1849 | .name = "weight", |
1850 | .flags = CFTYPE_NOT_ON_ROOT, |
1851 | .read_seq_string = cfq_print_weight, |
1852 | .write_u64 = cfq_set_weight, |
1853 | }, |
1854 | |
1855 | { |
1856 | .name = "leaf_weight_device", |
1857 | .read_seq_string = cfqg_print_leaf_weight_device, |
1858 | .write_string = cfqg_set_leaf_weight_device, |
1859 | .max_write_len = 256, |
1860 | }, |
1861 | { |
1862 | .name = "leaf_weight", |
1863 | .read_seq_string = cfq_print_leaf_weight, |
1864 | .write_u64 = cfq_set_leaf_weight, |
1865 | }, |
1866 | |
1867 | /* statistics, covers only the tasks in the cfqg */ |
1868 | { |
1869 | .name = "time", |
1870 | .private = offsetof(struct cfq_group, stats.time), |
1871 | .read_seq_string = cfqg_print_stat, |
1872 | }, |
1873 | { |
1874 | .name = "sectors", |
1875 | .private = offsetof(struct cfq_group, stats.sectors), |
1876 | .read_seq_string = cfqg_print_stat, |
1877 | }, |
1878 | { |
1879 | .name = "io_service_bytes", |
1880 | .private = offsetof(struct cfq_group, stats.service_bytes), |
1881 | .read_seq_string = cfqg_print_rwstat, |
1882 | }, |
1883 | { |
1884 | .name = "io_serviced", |
1885 | .private = offsetof(struct cfq_group, stats.serviced), |
1886 | .read_seq_string = cfqg_print_rwstat, |
1887 | }, |
1888 | { |
1889 | .name = "io_service_time", |
1890 | .private = offsetof(struct cfq_group, stats.service_time), |
1891 | .read_seq_string = cfqg_print_rwstat, |
1892 | }, |
1893 | { |
1894 | .name = "io_wait_time", |
1895 | .private = offsetof(struct cfq_group, stats.wait_time), |
1896 | .read_seq_string = cfqg_print_rwstat, |
1897 | }, |
1898 | { |
1899 | .name = "io_merged", |
1900 | .private = offsetof(struct cfq_group, stats.merged), |
1901 | .read_seq_string = cfqg_print_rwstat, |
1902 | }, |
1903 | { |
1904 | .name = "io_queued", |
1905 | .private = offsetof(struct cfq_group, stats.queued), |
1906 | .read_seq_string = cfqg_print_rwstat, |
1907 | }, |
1908 | |
1909 | /* the same statictics which cover the cfqg and its descendants */ |
1910 | { |
1911 | .name = "time_recursive", |
1912 | .private = offsetof(struct cfq_group, stats.time), |
1913 | .read_seq_string = cfqg_print_stat_recursive, |
1914 | }, |
1915 | { |
1916 | .name = "sectors_recursive", |
1917 | .private = offsetof(struct cfq_group, stats.sectors), |
1918 | .read_seq_string = cfqg_print_stat_recursive, |
1919 | }, |
1920 | { |
1921 | .name = "io_service_bytes_recursive", |
1922 | .private = offsetof(struct cfq_group, stats.service_bytes), |
1923 | .read_seq_string = cfqg_print_rwstat_recursive, |
1924 | }, |
1925 | { |
1926 | .name = "io_serviced_recursive", |
1927 | .private = offsetof(struct cfq_group, stats.serviced), |
1928 | .read_seq_string = cfqg_print_rwstat_recursive, |
1929 | }, |
1930 | { |
1931 | .name = "io_service_time_recursive", |
1932 | .private = offsetof(struct cfq_group, stats.service_time), |
1933 | .read_seq_string = cfqg_print_rwstat_recursive, |
1934 | }, |
1935 | { |
1936 | .name = "io_wait_time_recursive", |
1937 | .private = offsetof(struct cfq_group, stats.wait_time), |
1938 | .read_seq_string = cfqg_print_rwstat_recursive, |
1939 | }, |
1940 | { |
1941 | .name = "io_merged_recursive", |
1942 | .private = offsetof(struct cfq_group, stats.merged), |
1943 | .read_seq_string = cfqg_print_rwstat_recursive, |
1944 | }, |
1945 | { |
1946 | .name = "io_queued_recursive", |
1947 | .private = offsetof(struct cfq_group, stats.queued), |
1948 | .read_seq_string = cfqg_print_rwstat_recursive, |
1949 | }, |
1950 | #ifdef CONFIG_DEBUG_BLK_CGROUP |
1951 | { |
1952 | .name = "avg_queue_size", |
1953 | .read_seq_string = cfqg_print_avg_queue_size, |
1954 | }, |
1955 | { |
1956 | .name = "group_wait_time", |
1957 | .private = offsetof(struct cfq_group, stats.group_wait_time), |
1958 | .read_seq_string = cfqg_print_stat, |
1959 | }, |
1960 | { |
1961 | .name = "idle_time", |
1962 | .private = offsetof(struct cfq_group, stats.idle_time), |
1963 | .read_seq_string = cfqg_print_stat, |
1964 | }, |
1965 | { |
1966 | .name = "empty_time", |
1967 | .private = offsetof(struct cfq_group, stats.empty_time), |
1968 | .read_seq_string = cfqg_print_stat, |
1969 | }, |
1970 | { |
1971 | .name = "dequeue", |
1972 | .private = offsetof(struct cfq_group, stats.dequeue), |
1973 | .read_seq_string = cfqg_print_stat, |
1974 | }, |
1975 | { |
1976 | .name = "unaccounted_time", |
1977 | .private = offsetof(struct cfq_group, stats.unaccounted_time), |
1978 | .read_seq_string = cfqg_print_stat, |
1979 | }, |
1980 | #endif /* CONFIG_DEBUG_BLK_CGROUP */ |
1981 | { } /* terminate */ |
1982 | }; |
1983 | #else /* GROUP_IOSCHED */ |
1984 | static struct cfq_group *cfq_lookup_create_cfqg(struct cfq_data *cfqd, |
1985 | struct blkcg *blkcg) |
1986 | { |
1987 | return cfqd->root_group; |
1988 | } |
1989 | |
1990 | static inline void |
1991 | cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) { |
1992 | cfqq->cfqg = cfqg; |
1993 | } |
1994 | |
1995 | #endif /* GROUP_IOSCHED */ |
1996 | |
1997 | /* |
1998 | * The cfqd->service_trees holds all pending cfq_queue's that have |
1999 | * requests waiting to be processed. It is sorted in the order that |
2000 | * we will service the queues. |
2001 | */ |
2002 | static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
2003 | bool add_front) |
2004 | { |
2005 | struct rb_node **p, *parent; |
2006 | struct cfq_queue *__cfqq; |
2007 | unsigned long rb_key; |
2008 | struct cfq_rb_root *st; |
2009 | int left; |
2010 | int new_cfqq = 1; |
2011 | |
2012 | st = st_for(cfqq->cfqg, cfqq_class(cfqq), cfqq_type(cfqq)); |
2013 | if (cfq_class_idle(cfqq)) { |
2014 | rb_key = CFQ_IDLE_DELAY; |
2015 | parent = rb_last(&st->rb); |
2016 | if (parent && parent != &cfqq->rb_node) { |
2017 | __cfqq = rb_entry(parent, struct cfq_queue, rb_node); |
2018 | rb_key += __cfqq->rb_key; |
2019 | } else |
2020 | rb_key += jiffies; |
2021 | } else if (!add_front) { |
2022 | /* |
2023 | * Get our rb key offset. Subtract any residual slice |
2024 | * value carried from last service. A negative resid |
2025 | * count indicates slice overrun, and this should position |
2026 | * the next service time further away in the tree. |
2027 | */ |
2028 | rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies; |
2029 | rb_key -= cfqq->slice_resid; |
2030 | cfqq->slice_resid = 0; |
2031 | } else { |
2032 | rb_key = -HZ; |
2033 | __cfqq = cfq_rb_first(st); |
2034 | rb_key += __cfqq ? __cfqq->rb_key : jiffies; |
2035 | } |
2036 | |
2037 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) { |
2038 | new_cfqq = 0; |
2039 | /* |
2040 | * same position, nothing more to do |
2041 | */ |
2042 | if (rb_key == cfqq->rb_key && cfqq->service_tree == st) |
2043 | return; |
2044 | |
2045 | cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree); |
2046 | cfqq->service_tree = NULL; |
2047 | } |
2048 | |
2049 | left = 1; |
2050 | parent = NULL; |
2051 | cfqq->service_tree = st; |
2052 | p = &st->rb.rb_node; |
2053 | while (*p) { |
2054 | parent = *p; |
2055 | __cfqq = rb_entry(parent, struct cfq_queue, rb_node); |
2056 | |
2057 | /* |
2058 | * sort by key, that represents service time. |
2059 | */ |
2060 | if (time_before(rb_key, __cfqq->rb_key)) |
2061 | p = &parent->rb_left; |
2062 | else { |
2063 | p = &parent->rb_right; |
2064 | left = 0; |
2065 | } |
2066 | } |
2067 | |
2068 | if (left) |
2069 | st->left = &cfqq->rb_node; |
2070 | |
2071 | cfqq->rb_key = rb_key; |
2072 | rb_link_node(&cfqq->rb_node, parent, p); |
2073 | rb_insert_color(&cfqq->rb_node, &st->rb); |
2074 | st->count++; |
2075 | if (add_front || !new_cfqq) |
2076 | return; |
2077 | cfq_group_notify_queue_add(cfqd, cfqq->cfqg); |
2078 | } |
2079 | |
2080 | static struct cfq_queue * |
2081 | cfq_prio_tree_lookup(struct cfq_data *cfqd, struct rb_root *root, |
2082 | sector_t sector, struct rb_node **ret_parent, |
2083 | struct rb_node ***rb_link) |
2084 | { |
2085 | struct rb_node **p, *parent; |
2086 | struct cfq_queue *cfqq = NULL; |
2087 | |
2088 | parent = NULL; |
2089 | p = &root->rb_node; |
2090 | while (*p) { |
2091 | struct rb_node **n; |
2092 | |
2093 | parent = *p; |
2094 | cfqq = rb_entry(parent, struct cfq_queue, p_node); |
2095 | |
2096 | /* |
2097 | * Sort strictly based on sector. Smallest to the left, |
2098 | * largest to the right. |
2099 | */ |
2100 | if (sector > blk_rq_pos(cfqq->next_rq)) |
2101 | n = &(*p)->rb_right; |
2102 | else if (sector < blk_rq_pos(cfqq->next_rq)) |
2103 | n = &(*p)->rb_left; |
2104 | else |
2105 | break; |
2106 | p = n; |
2107 | cfqq = NULL; |
2108 | } |
2109 | |
2110 | *ret_parent = parent; |
2111 | if (rb_link) |
2112 | *rb_link = p; |
2113 | return cfqq; |
2114 | } |
2115 | |
2116 | static void cfq_prio_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
2117 | { |
2118 | struct rb_node **p, *parent; |
2119 | struct cfq_queue *__cfqq; |
2120 | |
2121 | if (cfqq->p_root) { |
2122 | rb_erase(&cfqq->p_node, cfqq->p_root); |
2123 | cfqq->p_root = NULL; |
2124 | } |
2125 | |
2126 | if (cfq_class_idle(cfqq)) |
2127 | return; |
2128 | if (!cfqq->next_rq) |
2129 | return; |
2130 | |
2131 | cfqq->p_root = &cfqd->prio_trees[cfqq->org_ioprio]; |
2132 | __cfqq = cfq_prio_tree_lookup(cfqd, cfqq->p_root, |
2133 | blk_rq_pos(cfqq->next_rq), &parent, &p); |
2134 | if (!__cfqq) { |
2135 | rb_link_node(&cfqq->p_node, parent, p); |
2136 | rb_insert_color(&cfqq->p_node, cfqq->p_root); |
2137 | } else |
2138 | cfqq->p_root = NULL; |
2139 | } |
2140 | |
2141 | /* |
2142 | * Update cfqq's position in the service tree. |
2143 | */ |
2144 | static void cfq_resort_rr_list(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
2145 | { |
2146 | /* |
2147 | * Resorting requires the cfqq to be on the RR list already. |
2148 | */ |
2149 | if (cfq_cfqq_on_rr(cfqq)) { |
2150 | cfq_service_tree_add(cfqd, cfqq, 0); |
2151 | cfq_prio_tree_add(cfqd, cfqq); |
2152 | } |
2153 | } |
2154 | |
2155 | /* |
2156 | * add to busy list of queues for service, trying to be fair in ordering |
2157 | * the pending list according to last request service |
2158 | */ |
2159 | static void cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
2160 | { |
2161 | cfq_log_cfqq(cfqd, cfqq, "add_to_rr"); |
2162 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
2163 | cfq_mark_cfqq_on_rr(cfqq); |
2164 | cfqd->busy_queues++; |
2165 | if (cfq_cfqq_sync(cfqq)) |
2166 | cfqd->busy_sync_queues++; |
2167 | |
2168 | cfq_resort_rr_list(cfqd, cfqq); |
2169 | } |
2170 | |
2171 | /* |
2172 | * Called when the cfqq no longer has requests pending, remove it from |
2173 | * the service tree. |
2174 | */ |
2175 | static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
2176 | { |
2177 | cfq_log_cfqq(cfqd, cfqq, "del_from_rr"); |
2178 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
2179 | cfq_clear_cfqq_on_rr(cfqq); |
2180 | |
2181 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) { |
2182 | cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree); |
2183 | cfqq->service_tree = NULL; |
2184 | } |
2185 | if (cfqq->p_root) { |
2186 | rb_erase(&cfqq->p_node, cfqq->p_root); |
2187 | cfqq->p_root = NULL; |
2188 | } |
2189 | |
2190 | cfq_group_notify_queue_del(cfqd, cfqq->cfqg); |
2191 | BUG_ON(!cfqd->busy_queues); |
2192 | cfqd->busy_queues--; |
2193 | if (cfq_cfqq_sync(cfqq)) |
2194 | cfqd->busy_sync_queues--; |
2195 | } |
2196 | |
2197 | /* |
2198 | * rb tree support functions |
2199 | */ |
2200 | static void cfq_del_rq_rb(struct request *rq) |
2201 | { |
2202 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
2203 | const int sync = rq_is_sync(rq); |
2204 | |
2205 | BUG_ON(!cfqq->queued[sync]); |
2206 | cfqq->queued[sync]--; |
2207 | |
2208 | elv_rb_del(&cfqq->sort_list, rq); |
2209 | |
2210 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) { |
2211 | /* |
2212 | * Queue will be deleted from service tree when we actually |
2213 | * expire it later. Right now just remove it from prio tree |
2214 | * as it is empty. |
2215 | */ |
2216 | if (cfqq->p_root) { |
2217 | rb_erase(&cfqq->p_node, cfqq->p_root); |
2218 | cfqq->p_root = NULL; |
2219 | } |
2220 | } |
2221 | } |
2222 | |
2223 | static void cfq_add_rq_rb(struct request *rq) |
2224 | { |
2225 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
2226 | struct cfq_data *cfqd = cfqq->cfqd; |
2227 | struct request *prev; |
2228 | |
2229 | cfqq->queued[rq_is_sync(rq)]++; |
2230 | |
2231 | elv_rb_add(&cfqq->sort_list, rq); |
2232 | |
2233 | if (!cfq_cfqq_on_rr(cfqq)) |
2234 | cfq_add_cfqq_rr(cfqd, cfqq); |
2235 | |
2236 | /* |
2237 | * check if this request is a better next-serve candidate |
2238 | */ |
2239 | prev = cfqq->next_rq; |
2240 | cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq, cfqd->last_position); |
2241 | |
2242 | /* |
2243 | * adjust priority tree position, if ->next_rq changes |
2244 | */ |
2245 | if (prev != cfqq->next_rq) |
2246 | cfq_prio_tree_add(cfqd, cfqq); |
2247 | |
2248 | BUG_ON(!cfqq->next_rq); |
2249 | } |
2250 | |
2251 | static void cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq) |
2252 | { |
2253 | elv_rb_del(&cfqq->sort_list, rq); |
2254 | cfqq->queued[rq_is_sync(rq)]--; |
2255 | cfqg_stats_update_io_remove(RQ_CFQG(rq), rq->cmd_flags); |
2256 | cfq_add_rq_rb(rq); |
2257 | cfqg_stats_update_io_add(RQ_CFQG(rq), cfqq->cfqd->serving_group, |
2258 | rq->cmd_flags); |
2259 | } |
2260 | |
2261 | static struct request * |
2262 | cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio) |
2263 | { |
2264 | struct task_struct *tsk = current; |
2265 | struct cfq_io_cq *cic; |
2266 | struct cfq_queue *cfqq; |
2267 | |
2268 | cic = cfq_cic_lookup(cfqd, tsk->io_context); |
2269 | if (!cic) |
2270 | return NULL; |
2271 | |
2272 | cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); |
2273 | if (cfqq) { |
2274 | sector_t sector = bio->bi_sector + bio_sectors(bio); |
2275 | |
2276 | return elv_rb_find(&cfqq->sort_list, sector); |
2277 | } |
2278 | |
2279 | return NULL; |
2280 | } |
2281 | |
2282 | static void cfq_activate_request(struct request_queue *q, struct request *rq) |
2283 | { |
2284 | struct cfq_data *cfqd = q->elevator->elevator_data; |
2285 | |
2286 | cfqd->rq_in_driver++; |
2287 | cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "activate rq, drv=%d", |
2288 | cfqd->rq_in_driver); |
2289 | |
2290 | cfqd->last_position = blk_rq_pos(rq) + blk_rq_sectors(rq); |
2291 | } |
2292 | |
2293 | static void cfq_deactivate_request(struct request_queue *q, struct request *rq) |
2294 | { |
2295 | struct cfq_data *cfqd = q->elevator->elevator_data; |
2296 | |
2297 | WARN_ON(!cfqd->rq_in_driver); |
2298 | cfqd->rq_in_driver--; |
2299 | cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "deactivate rq, drv=%d", |
2300 | cfqd->rq_in_driver); |
2301 | } |
2302 | |
2303 | static void cfq_remove_request(struct request *rq) |
2304 | { |
2305 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
2306 | |
2307 | if (cfqq->next_rq == rq) |
2308 | cfqq->next_rq = cfq_find_next_rq(cfqq->cfqd, cfqq, rq); |
2309 | |
2310 | list_del_init(&rq->queuelist); |
2311 | cfq_del_rq_rb(rq); |
2312 | |
2313 | cfqq->cfqd->rq_queued--; |
2314 | cfqg_stats_update_io_remove(RQ_CFQG(rq), rq->cmd_flags); |
2315 | if (rq->cmd_flags & REQ_PRIO) { |
2316 | WARN_ON(!cfqq->prio_pending); |
2317 | cfqq->prio_pending--; |
2318 | } |
2319 | } |
2320 | |
2321 | static int cfq_merge(struct request_queue *q, struct request **req, |
2322 | struct bio *bio) |
2323 | { |
2324 | struct cfq_data *cfqd = q->elevator->elevator_data; |
2325 | struct request *__rq; |
2326 | |
2327 | __rq = cfq_find_rq_fmerge(cfqd, bio); |
2328 | if (__rq && elv_rq_merge_ok(__rq, bio)) { |
2329 | *req = __rq; |
2330 | return ELEVATOR_FRONT_MERGE; |
2331 | } |
2332 | |
2333 | return ELEVATOR_NO_MERGE; |
2334 | } |
2335 | |
2336 | static void cfq_merged_request(struct request_queue *q, struct request *req, |
2337 | int type) |
2338 | { |
2339 | if (type == ELEVATOR_FRONT_MERGE) { |
2340 | struct cfq_queue *cfqq = RQ_CFQQ(req); |
2341 | |
2342 | cfq_reposition_rq_rb(cfqq, req); |
2343 | } |
2344 | } |
2345 | |
2346 | static void cfq_bio_merged(struct request_queue *q, struct request *req, |
2347 | struct bio *bio) |
2348 | { |
2349 | cfqg_stats_update_io_merged(RQ_CFQG(req), bio->bi_rw); |
2350 | } |
2351 | |
2352 | static void |
2353 | cfq_merged_requests(struct request_queue *q, struct request *rq, |
2354 | struct request *next) |
2355 | { |
2356 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
2357 | struct cfq_data *cfqd = q->elevator->elevator_data; |
2358 | |
2359 | /* |
2360 | * reposition in fifo if next is older than rq |
2361 | */ |
2362 | if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && |
2363 | time_before(rq_fifo_time(next), rq_fifo_time(rq)) && |
2364 | cfqq == RQ_CFQQ(next)) { |
2365 | list_move(&rq->queuelist, &next->queuelist); |
2366 | rq_set_fifo_time(rq, rq_fifo_time(next)); |
2367 | } |
2368 | |
2369 | if (cfqq->next_rq == next) |
2370 | cfqq->next_rq = rq; |
2371 | cfq_remove_request(next); |
2372 | cfqg_stats_update_io_merged(RQ_CFQG(rq), next->cmd_flags); |
2373 | |
2374 | cfqq = RQ_CFQQ(next); |
2375 | /* |
2376 | * all requests of this queue are merged to other queues, delete it |
2377 | * from the service tree. If it's the active_queue, |
2378 | * cfq_dispatch_requests() will choose to expire it or do idle |
2379 | */ |
2380 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list) && |
2381 | cfqq != cfqd->active_queue) |
2382 | cfq_del_cfqq_rr(cfqd, cfqq); |
2383 | } |
2384 | |
2385 | static int cfq_allow_merge(struct request_queue *q, struct request *rq, |
2386 | struct bio *bio) |
2387 | { |
2388 | struct cfq_data *cfqd = q->elevator->elevator_data; |
2389 | struct cfq_io_cq *cic; |
2390 | struct cfq_queue *cfqq; |
2391 | |
2392 | /* |
2393 | * Disallow merge of a sync bio into an async request. |
2394 | */ |
2395 | if (cfq_bio_sync(bio) && !rq_is_sync(rq)) |
2396 | return false; |
2397 | |
2398 | /* |
2399 | * Lookup the cfqq that this bio will be queued with and allow |
2400 | * merge only if rq is queued there. |
2401 | */ |
2402 | cic = cfq_cic_lookup(cfqd, current->io_context); |
2403 | if (!cic) |
2404 | return false; |
2405 | |
2406 | cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); |
2407 | return cfqq == RQ_CFQQ(rq); |
2408 | } |
2409 | |
2410 | static inline void cfq_del_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
2411 | { |
2412 | del_timer(&cfqd->idle_slice_timer); |
2413 | cfqg_stats_update_idle_time(cfqq->cfqg); |
2414 | } |
2415 | |
2416 | static void __cfq_set_active_queue(struct cfq_data *cfqd, |
2417 | struct cfq_queue *cfqq) |
2418 | { |
2419 | if (cfqq) { |
2420 | cfq_log_cfqq(cfqd, cfqq, "set_active wl_class:%d wl_type:%d", |
2421 | cfqd->serving_wl_class, cfqd->serving_wl_type); |
2422 | cfqg_stats_update_avg_queue_size(cfqq->cfqg); |
2423 | cfqq->slice_start = 0; |
2424 | cfqq->dispatch_start = jiffies; |
2425 | cfqq->allocated_slice = 0; |
2426 | cfqq->slice_end = 0; |
2427 | cfqq->slice_dispatch = 0; |
2428 | cfqq->nr_sectors = 0; |
2429 | |
2430 | cfq_clear_cfqq_wait_request(cfqq); |
2431 | cfq_clear_cfqq_must_dispatch(cfqq); |
2432 | cfq_clear_cfqq_must_alloc_slice(cfqq); |
2433 | cfq_clear_cfqq_fifo_expire(cfqq); |
2434 | cfq_mark_cfqq_slice_new(cfqq); |
2435 | |
2436 | cfq_del_timer(cfqd, cfqq); |
2437 | } |
2438 | |
2439 | cfqd->active_queue = cfqq; |
2440 | } |
2441 | |
2442 | /* |
2443 | * current cfqq expired its slice (or was too idle), select new one |
2444 | */ |
2445 | static void |
2446 | __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
2447 | bool timed_out) |
2448 | { |
2449 | cfq_log_cfqq(cfqd, cfqq, "slice expired t=%d", timed_out); |
2450 | |
2451 | if (cfq_cfqq_wait_request(cfqq)) |
2452 | cfq_del_timer(cfqd, cfqq); |
2453 | |
2454 | cfq_clear_cfqq_wait_request(cfqq); |
2455 | cfq_clear_cfqq_wait_busy(cfqq); |
2456 | |
2457 | /* |
2458 | * If this cfqq is shared between multiple processes, check to |
2459 | * make sure that those processes are still issuing I/Os within |
2460 | * the mean seek distance. If not, it may be time to break the |
2461 | * queues apart again. |
2462 | */ |
2463 | if (cfq_cfqq_coop(cfqq) && CFQQ_SEEKY(cfqq)) |
2464 | cfq_mark_cfqq_split_coop(cfqq); |
2465 | |
2466 | /* |
2467 | * store what was left of this slice, if the queue idled/timed out |
2468 | */ |
2469 | if (timed_out) { |
2470 | if (cfq_cfqq_slice_new(cfqq)) |
2471 | cfqq->slice_resid = cfq_scaled_cfqq_slice(cfqd, cfqq); |
2472 | else |
2473 | cfqq->slice_resid = cfqq->slice_end - jiffies; |
2474 | cfq_log_cfqq(cfqd, cfqq, "resid=%ld", cfqq->slice_resid); |
2475 | } |
2476 | |
2477 | cfq_group_served(cfqd, cfqq->cfqg, cfqq); |
2478 | |
2479 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) |
2480 | cfq_del_cfqq_rr(cfqd, cfqq); |
2481 | |
2482 | cfq_resort_rr_list(cfqd, cfqq); |
2483 | |
2484 | if (cfqq == cfqd->active_queue) |
2485 | cfqd->active_queue = NULL; |
2486 | |
2487 | if (cfqd->active_cic) { |
2488 | put_io_context(cfqd->active_cic->icq.ioc); |
2489 | cfqd->active_cic = NULL; |
2490 | } |
2491 | } |
2492 | |
2493 | static inline void cfq_slice_expired(struct cfq_data *cfqd, bool timed_out) |
2494 | { |
2495 | struct cfq_queue *cfqq = cfqd->active_queue; |
2496 | |
2497 | if (cfqq) |
2498 | __cfq_slice_expired(cfqd, cfqq, timed_out); |
2499 | } |
2500 | |
2501 | /* |
2502 | * Get next queue for service. Unless we have a queue preemption, |
2503 | * we'll simply select the first cfqq in the service tree. |
2504 | */ |
2505 | static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd) |
2506 | { |
2507 | struct cfq_rb_root *st = st_for(cfqd->serving_group, |
2508 | cfqd->serving_wl_class, cfqd->serving_wl_type); |
2509 | |
2510 | if (!cfqd->rq_queued) |
2511 | return NULL; |
2512 | |
2513 | /* There is nothing to dispatch */ |
2514 | if (!st) |
2515 | return NULL; |
2516 | if (RB_EMPTY_ROOT(&st->rb)) |
2517 | return NULL; |
2518 | return cfq_rb_first(st); |
2519 | } |
2520 | |
2521 | static struct cfq_queue *cfq_get_next_queue_forced(struct cfq_data *cfqd) |
2522 | { |
2523 | struct cfq_group *cfqg; |
2524 | struct cfq_queue *cfqq; |
2525 | int i, j; |
2526 | struct cfq_rb_root *st; |
2527 | |
2528 | if (!cfqd->rq_queued) |
2529 | return NULL; |
2530 | |
2531 | cfqg = cfq_get_next_cfqg(cfqd); |
2532 | if (!cfqg) |
2533 | return NULL; |
2534 | |
2535 | for_each_cfqg_st(cfqg, i, j, st) |
2536 | if ((cfqq = cfq_rb_first(st)) != NULL) |
2537 | return cfqq; |
2538 | return NULL; |
2539 | } |
2540 | |
2541 | /* |
2542 | * Get and set a new active queue for service. |
2543 | */ |
2544 | static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd, |
2545 | struct cfq_queue *cfqq) |
2546 | { |
2547 | if (!cfqq) |
2548 | cfqq = cfq_get_next_queue(cfqd); |
2549 | |
2550 | __cfq_set_active_queue(cfqd, cfqq); |
2551 | return cfqq; |
2552 | } |
2553 | |
2554 | static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd, |
2555 | struct request *rq) |
2556 | { |
2557 | if (blk_rq_pos(rq) >= cfqd->last_position) |
2558 | return blk_rq_pos(rq) - cfqd->last_position; |
2559 | else |
2560 | return cfqd->last_position - blk_rq_pos(rq); |
2561 | } |
2562 | |
2563 | static inline int cfq_rq_close(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
2564 | struct request *rq) |
2565 | { |
2566 | return cfq_dist_from_last(cfqd, rq) <= CFQQ_CLOSE_THR; |
2567 | } |
2568 | |
2569 | static struct cfq_queue *cfqq_close(struct cfq_data *cfqd, |
2570 | struct cfq_queue *cur_cfqq) |
2571 | { |
2572 | struct rb_root *root = &cfqd->prio_trees[cur_cfqq->org_ioprio]; |
2573 | struct rb_node *parent, *node; |
2574 | struct cfq_queue *__cfqq; |
2575 | sector_t sector = cfqd->last_position; |
2576 | |
2577 | if (RB_EMPTY_ROOT(root)) |
2578 | return NULL; |
2579 | |
2580 | /* |
2581 | * First, if we find a request starting at the end of the last |
2582 | * request, choose it. |
2583 | */ |
2584 | __cfqq = cfq_prio_tree_lookup(cfqd, root, sector, &parent, NULL); |
2585 | if (__cfqq) |
2586 | return __cfqq; |
2587 | |
2588 | /* |
2589 | * If the exact sector wasn't found, the parent of the NULL leaf |
2590 | * will contain the closest sector. |
2591 | */ |
2592 | __cfqq = rb_entry(parent, struct cfq_queue, p_node); |
2593 | if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq)) |
2594 | return __cfqq; |
2595 | |
2596 | if (blk_rq_pos(__cfqq->next_rq) < sector) |
2597 | node = rb_next(&__cfqq->p_node); |
2598 | else |
2599 | node = rb_prev(&__cfqq->p_node); |
2600 | if (!node) |
2601 | return NULL; |
2602 | |
2603 | __cfqq = rb_entry(node, struct cfq_queue, p_node); |
2604 | if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq)) |
2605 | return __cfqq; |
2606 | |
2607 | return NULL; |
2608 | } |
2609 | |
2610 | /* |
2611 | * cfqd - obvious |
2612 | * cur_cfqq - passed in so that we don't decide that the current queue is |
2613 | * closely cooperating with itself. |
2614 | * |
2615 | * So, basically we're assuming that that cur_cfqq has dispatched at least |
2616 | * one request, and that cfqd->last_position reflects a position on the disk |
2617 | * associated with the I/O issued by cur_cfqq. I'm not sure this is a valid |
2618 | * assumption. |
2619 | */ |
2620 | static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd, |
2621 | struct cfq_queue *cur_cfqq) |
2622 | { |
2623 | struct cfq_queue *cfqq; |
2624 | |
2625 | if (cfq_class_idle(cur_cfqq)) |
2626 | return NULL; |
2627 | if (!cfq_cfqq_sync(cur_cfqq)) |
2628 | return NULL; |
2629 | if (CFQQ_SEEKY(cur_cfqq)) |
2630 | return NULL; |
2631 | |
2632 | /* |
2633 | * Don't search priority tree if it's the only queue in the group. |
2634 | */ |
2635 | if (cur_cfqq->cfqg->nr_cfqq == 1) |
2636 | return NULL; |
2637 | |
2638 | /* |
2639 | * We should notice if some of the queues are cooperating, eg |
2640 | * working closely on the same area of the disk. In that case, |
2641 | * we can group them together and don't waste time idling. |
2642 | */ |
2643 | cfqq = cfqq_close(cfqd, cur_cfqq); |
2644 | if (!cfqq) |
2645 | return NULL; |
2646 | |
2647 | /* If new queue belongs to different cfq_group, don't choose it */ |
2648 | if (cur_cfqq->cfqg != cfqq->cfqg) |
2649 | return NULL; |
2650 | |
2651 | /* |
2652 | * It only makes sense to merge sync queues. |
2653 | */ |
2654 | if (!cfq_cfqq_sync(cfqq)) |
2655 | return NULL; |
2656 | if (CFQQ_SEEKY(cfqq)) |
2657 | return NULL; |
2658 | |
2659 | /* |
2660 | * Do not merge queues of different priority classes |
2661 | */ |
2662 | if (cfq_class_rt(cfqq) != cfq_class_rt(cur_cfqq)) |
2663 | return NULL; |
2664 | |
2665 | return cfqq; |
2666 | } |
2667 | |
2668 | /* |
2669 | * Determine whether we should enforce idle window for this queue. |
2670 | */ |
2671 | |
2672 | static bool cfq_should_idle(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
2673 | { |
2674 | enum wl_class_t wl_class = cfqq_class(cfqq); |
2675 | struct cfq_rb_root *st = cfqq->service_tree; |
2676 | |
2677 | BUG_ON(!st); |
2678 | BUG_ON(!st->count); |
2679 | |
2680 | if (!cfqd->cfq_slice_idle) |
2681 | return false; |
2682 | |
2683 | /* We never do for idle class queues. */ |
2684 | if (wl_class == IDLE_WORKLOAD) |
2685 | return false; |
2686 | |
2687 | /* We do for queues that were marked with idle window flag. */ |
2688 | if (cfq_cfqq_idle_window(cfqq) && |
2689 | !(blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag)) |
2690 | return true; |
2691 | |
2692 | /* |
2693 | * Otherwise, we do only if they are the last ones |
2694 | * in their service tree. |
2695 | */ |
2696 | if (st->count == 1 && cfq_cfqq_sync(cfqq) && |
2697 | !cfq_io_thinktime_big(cfqd, &st->ttime, false)) |
2698 | return true; |
2699 | cfq_log_cfqq(cfqd, cfqq, "Not idling. st->count:%d", st->count); |
2700 | return false; |
2701 | } |
2702 | |
2703 | static void cfq_arm_slice_timer(struct cfq_data *cfqd) |
2704 | { |
2705 | struct cfq_queue *cfqq = cfqd->active_queue; |
2706 | struct cfq_io_cq *cic; |
2707 | unsigned long sl, group_idle = 0; |
2708 | |
2709 | /* |
2710 | * SSD device without seek penalty, disable idling. But only do so |
2711 | * for devices that support queuing, otherwise we still have a problem |
2712 | * with sync vs async workloads. |
2713 | */ |
2714 | if (blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag) |
2715 | return; |
2716 | |
2717 | WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list)); |
2718 | WARN_ON(cfq_cfqq_slice_new(cfqq)); |
2719 | |
2720 | /* |
2721 | * idle is disabled, either manually or by past process history |
2722 | */ |
2723 | if (!cfq_should_idle(cfqd, cfqq)) { |
2724 | /* no queue idling. Check for group idling */ |
2725 | if (cfqd->cfq_group_idle) |
2726 | group_idle = cfqd->cfq_group_idle; |
2727 | else |
2728 | return; |
2729 | } |
2730 | |
2731 | /* |
2732 | * still active requests from this queue, don't idle |
2733 | */ |
2734 | if (cfqq->dispatched) |
2735 | return; |
2736 | |
2737 | /* |
2738 | * task has exited, don't wait |
2739 | */ |
2740 | cic = cfqd->active_cic; |
2741 | if (!cic || !atomic_read(&cic->icq.ioc->active_ref)) |
2742 | return; |
2743 | |
2744 | /* |
2745 | * If our average think time is larger than the remaining time |
2746 | * slice, then don't idle. This avoids overrunning the allotted |
2747 | * time slice. |
2748 | */ |
2749 | if (sample_valid(cic->ttime.ttime_samples) && |
2750 | (cfqq->slice_end - jiffies < cic->ttime.ttime_mean)) { |
2751 | cfq_log_cfqq(cfqd, cfqq, "Not idling. think_time:%lu", |
2752 | cic->ttime.ttime_mean); |
2753 | return; |
2754 | } |
2755 | |
2756 | /* There are other queues in the group, don't do group idle */ |
2757 | if (group_idle && cfqq->cfqg->nr_cfqq > 1) |
2758 | return; |
2759 | |
2760 | cfq_mark_cfqq_wait_request(cfqq); |
2761 | |
2762 | if (group_idle) |
2763 | sl = cfqd->cfq_group_idle; |
2764 | else |
2765 | sl = cfqd->cfq_slice_idle; |
2766 | |
2767 | mod_timer(&cfqd->idle_slice_timer, jiffies + sl); |
2768 | cfqg_stats_set_start_idle_time(cfqq->cfqg); |
2769 | cfq_log_cfqq(cfqd, cfqq, "arm_idle: %lu group_idle: %d", sl, |
2770 | group_idle ? 1 : 0); |
2771 | } |
2772 | |
2773 | /* |
2774 | * Move request from internal lists to the request queue dispatch list. |
2775 | */ |
2776 | static void cfq_dispatch_insert(struct request_queue *q, struct request *rq) |
2777 | { |
2778 | struct cfq_data *cfqd = q->elevator->elevator_data; |
2779 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
2780 | |
2781 | cfq_log_cfqq(cfqd, cfqq, "dispatch_insert"); |
2782 | |
2783 | cfqq->next_rq = cfq_find_next_rq(cfqd, cfqq, rq); |
2784 | cfq_remove_request(rq); |
2785 | cfqq->dispatched++; |
2786 | (RQ_CFQG(rq))->dispatched++; |
2787 | elv_dispatch_sort(q, rq); |
2788 | |
2789 | cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]++; |
2790 | cfqq->nr_sectors += blk_rq_sectors(rq); |
2791 | cfqg_stats_update_dispatch(cfqq->cfqg, blk_rq_bytes(rq), rq->cmd_flags); |
2792 | } |
2793 | |
2794 | /* |
2795 | * return expired entry, or NULL to just start from scratch in rbtree |
2796 | */ |
2797 | static struct request *cfq_check_fifo(struct cfq_queue *cfqq) |
2798 | { |
2799 | struct request *rq = NULL; |
2800 | |
2801 | if (cfq_cfqq_fifo_expire(cfqq)) |
2802 | return NULL; |
2803 | |
2804 | cfq_mark_cfqq_fifo_expire(cfqq); |
2805 | |
2806 | if (list_empty(&cfqq->fifo)) |
2807 | return NULL; |
2808 | |
2809 | rq = rq_entry_fifo(cfqq->fifo.next); |
2810 | if (time_before(jiffies, rq_fifo_time(rq))) |
2811 | rq = NULL; |
2812 | |
2813 | cfq_log_cfqq(cfqq->cfqd, cfqq, "fifo=%p", rq); |
2814 | return rq; |
2815 | } |
2816 | |
2817 | static inline int |
2818 | cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
2819 | { |
2820 | const int base_rq = cfqd->cfq_slice_async_rq; |
2821 | |
2822 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); |
2823 | |
2824 | return 2 * base_rq * (IOPRIO_BE_NR - cfqq->ioprio); |
2825 | } |
2826 | |
2827 | /* |
2828 | * Must be called with the queue_lock held. |
2829 | */ |
2830 | static int cfqq_process_refs(struct cfq_queue *cfqq) |
2831 | { |
2832 | int process_refs, io_refs; |
2833 | |
2834 | io_refs = cfqq->allocated[READ] + cfqq->allocated[WRITE]; |
2835 | process_refs = cfqq->ref - io_refs; |
2836 | BUG_ON(process_refs < 0); |
2837 | return process_refs; |
2838 | } |
2839 | |
2840 | static void cfq_setup_merge(struct cfq_queue *cfqq, struct cfq_queue *new_cfqq) |
2841 | { |
2842 | int process_refs, new_process_refs; |
2843 | struct cfq_queue *__cfqq; |
2844 | |
2845 | /* |
2846 | * If there are no process references on the new_cfqq, then it is |
2847 | * unsafe to follow the ->new_cfqq chain as other cfqq's in the |
2848 | * chain may have dropped their last reference (not just their |
2849 | * last process reference). |
2850 | */ |
2851 | if (!cfqq_process_refs(new_cfqq)) |
2852 | return; |
2853 | |
2854 | /* Avoid a circular list and skip interim queue merges */ |
2855 | while ((__cfqq = new_cfqq->new_cfqq)) { |
2856 | if (__cfqq == cfqq) |
2857 | return; |
2858 | new_cfqq = __cfqq; |
2859 | } |
2860 | |
2861 | process_refs = cfqq_process_refs(cfqq); |
2862 | new_process_refs = cfqq_process_refs(new_cfqq); |
2863 | /* |
2864 | * If the process for the cfqq has gone away, there is no |
2865 | * sense in merging the queues. |
2866 | */ |
2867 | if (process_refs == 0 || new_process_refs == 0) |
2868 | return; |
2869 | |
2870 | /* |
2871 | * Merge in the direction of the lesser amount of work. |
2872 | */ |
2873 | if (new_process_refs >= process_refs) { |
2874 | cfqq->new_cfqq = new_cfqq; |
2875 | new_cfqq->ref += process_refs; |
2876 | } else { |
2877 | new_cfqq->new_cfqq = cfqq; |
2878 | cfqq->ref += new_process_refs; |
2879 | } |
2880 | } |
2881 | |
2882 | static enum wl_type_t cfq_choose_wl_type(struct cfq_data *cfqd, |
2883 | struct cfq_group *cfqg, enum wl_class_t wl_class) |
2884 | { |
2885 | struct cfq_queue *queue; |
2886 | int i; |
2887 | bool key_valid = false; |
2888 | unsigned long lowest_key = 0; |
2889 | enum wl_type_t cur_best = SYNC_NOIDLE_WORKLOAD; |
2890 | |
2891 | for (i = 0; i <= SYNC_WORKLOAD; ++i) { |
2892 | /* select the one with lowest rb_key */ |
2893 | queue = cfq_rb_first(st_for(cfqg, wl_class, i)); |
2894 | if (queue && |
2895 | (!key_valid || time_before(queue->rb_key, lowest_key))) { |
2896 | lowest_key = queue->rb_key; |
2897 | cur_best = i; |
2898 | key_valid = true; |
2899 | } |
2900 | } |
2901 | |
2902 | return cur_best; |
2903 | } |
2904 | |
2905 | static void |
2906 | choose_wl_class_and_type(struct cfq_data *cfqd, struct cfq_group *cfqg) |
2907 | { |
2908 | unsigned slice; |
2909 | unsigned count; |
2910 | struct cfq_rb_root *st; |
2911 | unsigned group_slice; |
2912 | enum wl_class_t original_class = cfqd->serving_wl_class; |
2913 | |
2914 | /* Choose next priority. RT > BE > IDLE */ |
2915 | if (cfq_group_busy_queues_wl(RT_WORKLOAD, cfqd, cfqg)) |
2916 | cfqd->serving_wl_class = RT_WORKLOAD; |
2917 | else if (cfq_group_busy_queues_wl(BE_WORKLOAD, cfqd, cfqg)) |
2918 | cfqd->serving_wl_class = BE_WORKLOAD; |
2919 | else { |
2920 | cfqd->serving_wl_class = IDLE_WORKLOAD; |
2921 | cfqd->workload_expires = jiffies + 1; |
2922 | return; |
2923 | } |
2924 | |
2925 | if (original_class != cfqd->serving_wl_class) |
2926 | goto new_workload; |
2927 | |
2928 | /* |
2929 | * For RT and BE, we have to choose also the type |
2930 | * (SYNC, SYNC_NOIDLE, ASYNC), and to compute a workload |
2931 | * expiration time |
2932 | */ |
2933 | st = st_for(cfqg, cfqd->serving_wl_class, cfqd->serving_wl_type); |
2934 | count = st->count; |
2935 | |
2936 | /* |
2937 | * check workload expiration, and that we still have other queues ready |
2938 | */ |
2939 | if (count && !time_after(jiffies, cfqd->workload_expires)) |
2940 | return; |
2941 | |
2942 | new_workload: |
2943 | /* otherwise select new workload type */ |
2944 | cfqd->serving_wl_type = cfq_choose_wl_type(cfqd, cfqg, |
2945 | cfqd->serving_wl_class); |
2946 | st = st_for(cfqg, cfqd->serving_wl_class, cfqd->serving_wl_type); |
2947 | count = st->count; |
2948 | |
2949 | /* |
2950 | * the workload slice is computed as a fraction of target latency |
2951 | * proportional to the number of queues in that workload, over |
2952 | * all the queues in the same priority class |
2953 | */ |
2954 | group_slice = cfq_group_slice(cfqd, cfqg); |
2955 | |
2956 | slice = group_slice * count / |
2957 | max_t(unsigned, cfqg->busy_queues_avg[cfqd->serving_wl_class], |
2958 | cfq_group_busy_queues_wl(cfqd->serving_wl_class, cfqd, |
2959 | cfqg)); |
2960 | |
2961 | if (cfqd->serving_wl_type == ASYNC_WORKLOAD) { |
2962 | unsigned int tmp; |
2963 | |
2964 | /* |
2965 | * Async queues are currently system wide. Just taking |
2966 | * proportion of queues with-in same group will lead to higher |
2967 | * async ratio system wide as generally root group is going |
2968 | * to have higher weight. A more accurate thing would be to |
2969 | * calculate system wide asnc/sync ratio. |
2970 | */ |
2971 | tmp = cfqd->cfq_target_latency * |
2972 | cfqg_busy_async_queues(cfqd, cfqg); |
2973 | tmp = tmp/cfqd->busy_queues; |
2974 | slice = min_t(unsigned, slice, tmp); |
2975 | |
2976 | /* async workload slice is scaled down according to |
2977 | * the sync/async slice ratio. */ |
2978 | slice = slice * cfqd->cfq_slice[0] / cfqd->cfq_slice[1]; |
2979 | } else |
2980 | /* sync workload slice is at least 2 * cfq_slice_idle */ |
2981 | slice = max(slice, 2 * cfqd->cfq_slice_idle); |
2982 | |
2983 | slice = max_t(unsigned, slice, CFQ_MIN_TT); |
2984 | cfq_log(cfqd, "workload slice:%d", slice); |
2985 | cfqd->workload_expires = jiffies + slice; |
2986 | } |
2987 | |
2988 | static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd) |
2989 | { |
2990 | struct cfq_rb_root *st = &cfqd->grp_service_tree; |
2991 | struct cfq_group *cfqg; |
2992 | |
2993 | if (RB_EMPTY_ROOT(&st->rb)) |
2994 | return NULL; |
2995 | cfqg = cfq_rb_first_group(st); |
2996 | update_min_vdisktime(st); |
2997 | return cfqg; |
2998 | } |
2999 | |
3000 | static void cfq_choose_cfqg(struct cfq_data *cfqd) |
3001 | { |
3002 | struct cfq_group *cfqg = cfq_get_next_cfqg(cfqd); |
3003 | |
3004 | cfqd->serving_group = cfqg; |
3005 | |
3006 | /* Restore the workload type data */ |
3007 | if (cfqg->saved_wl_slice) { |
3008 | cfqd->workload_expires = jiffies + cfqg->saved_wl_slice; |
3009 | cfqd->serving_wl_type = cfqg->saved_wl_type; |
3010 | cfqd->serving_wl_class = cfqg->saved_wl_class; |
3011 | } else |
3012 | cfqd->workload_expires = jiffies - 1; |
3013 | |
3014 | choose_wl_class_and_type(cfqd, cfqg); |
3015 | } |
3016 | |
3017 | /* |
3018 | * Select a queue for service. If we have a current active queue, |
3019 | * check whether to continue servicing it, or retrieve and set a new one. |
3020 | */ |
3021 | static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) |
3022 | { |
3023 | struct cfq_queue *cfqq, *new_cfqq = NULL; |
3024 | |
3025 | cfqq = cfqd->active_queue; |
3026 | if (!cfqq) |
3027 | goto new_queue; |
3028 | |
3029 | if (!cfqd->rq_queued) |
3030 | return NULL; |
3031 | |
3032 | /* |
3033 | * We were waiting for group to get backlogged. Expire the queue |
3034 | */ |
3035 | if (cfq_cfqq_wait_busy(cfqq) && !RB_EMPTY_ROOT(&cfqq->sort_list)) |
3036 | goto expire; |
3037 | |
3038 | /* |
3039 | * The active queue has run out of time, expire it and select new. |
3040 | */ |
3041 | if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq)) { |
3042 | /* |
3043 | * If slice had not expired at the completion of last request |
3044 | * we might not have turned on wait_busy flag. Don't expire |
3045 | * the queue yet. Allow the group to get backlogged. |
3046 | * |
3047 | * The very fact that we have used the slice, that means we |
3048 | * have been idling all along on this queue and it should be |
3049 | * ok to wait for this request to complete. |
3050 | */ |
3051 | if (cfqq->cfqg->nr_cfqq == 1 && RB_EMPTY_ROOT(&cfqq->sort_list) |
3052 | && cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) { |
3053 | cfqq = NULL; |
3054 | goto keep_queue; |
3055 | } else |
3056 | goto check_group_idle; |
3057 | } |
3058 | |
3059 | /* |
3060 | * The active queue has requests and isn't expired, allow it to |
3061 | * dispatch. |
3062 | */ |
3063 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
3064 | goto keep_queue; |
3065 | |
3066 | /* |
3067 | * If another queue has a request waiting within our mean seek |
3068 | * distance, let it run. The expire code will check for close |
3069 | * cooperators and put the close queue at the front of the service |
3070 | * tree. If possible, merge the expiring queue with the new cfqq. |
3071 | */ |
3072 | new_cfqq = cfq_close_cooperator(cfqd, cfqq); |
3073 | if (new_cfqq) { |
3074 | if (!cfqq->new_cfqq) |
3075 | cfq_setup_merge(cfqq, new_cfqq); |
3076 | goto expire; |
3077 | } |
3078 | |
3079 | /* |
3080 | * No requests pending. If the active queue still has requests in |
3081 | * flight or is idling for a new request, allow either of these |
3082 | * conditions to happen (or time out) before selecting a new queue. |
3083 | */ |
3084 | if (timer_pending(&cfqd->idle_slice_timer)) { |
3085 | cfqq = NULL; |
3086 | goto keep_queue; |
3087 | } |
3088 | |
3089 | /* |
3090 | * This is a deep seek queue, but the device is much faster than |
3091 | * the queue can deliver, don't idle |
3092 | **/ |
3093 | if (CFQQ_SEEKY(cfqq) && cfq_cfqq_idle_window(cfqq) && |
3094 | (cfq_cfqq_slice_new(cfqq) || |
3095 | (cfqq->slice_end - jiffies > jiffies - cfqq->slice_start))) { |
3096 | cfq_clear_cfqq_deep(cfqq); |
3097 | cfq_clear_cfqq_idle_window(cfqq); |
3098 | } |
3099 | |
3100 | if (cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) { |
3101 | cfqq = NULL; |
3102 | goto keep_queue; |
3103 | } |
3104 | |
3105 | /* |
3106 | * If group idle is enabled and there are requests dispatched from |
3107 | * this group, wait for requests to complete. |
3108 | */ |
3109 | check_group_idle: |
3110 | if (cfqd->cfq_group_idle && cfqq->cfqg->nr_cfqq == 1 && |
3111 | cfqq->cfqg->dispatched && |
3112 | !cfq_io_thinktime_big(cfqd, &cfqq->cfqg->ttime, true)) { |
3113 | cfqq = NULL; |
3114 | goto keep_queue; |
3115 | } |
3116 | |
3117 | expire: |
3118 | cfq_slice_expired(cfqd, 0); |
3119 | new_queue: |
3120 | /* |
3121 | * Current queue expired. Check if we have to switch to a new |
3122 | * service tree |
3123 | */ |
3124 | if (!new_cfqq) |
3125 | cfq_choose_cfqg(cfqd); |
3126 | |
3127 | cfqq = cfq_set_active_queue(cfqd, new_cfqq); |
3128 | keep_queue: |
3129 | return cfqq; |
3130 | } |
3131 | |
3132 | static int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq) |
3133 | { |
3134 | int dispatched = 0; |
3135 | |
3136 | while (cfqq->next_rq) { |
3137 | cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq); |
3138 | dispatched++; |
3139 | } |
3140 | |
3141 | BUG_ON(!list_empty(&cfqq->fifo)); |
3142 | |
3143 | /* By default cfqq is not expired if it is empty. Do it explicitly */ |
3144 | __cfq_slice_expired(cfqq->cfqd, cfqq, 0); |
3145 | return dispatched; |
3146 | } |
3147 | |
3148 | /* |
3149 | * Drain our current requests. Used for barriers and when switching |
3150 | * io schedulers on-the-fly. |
3151 | */ |
3152 | static int cfq_forced_dispatch(struct cfq_data *cfqd) |
3153 | { |
3154 | struct cfq_queue *cfqq; |
3155 | int dispatched = 0; |
3156 | |
3157 | /* Expire the timeslice of the current active queue first */ |
3158 | cfq_slice_expired(cfqd, 0); |
3159 | while ((cfqq = cfq_get_next_queue_forced(cfqd)) != NULL) { |
3160 | __cfq_set_active_queue(cfqd, cfqq); |
3161 | dispatched += __cfq_forced_dispatch_cfqq(cfqq); |
3162 | } |
3163 | |
3164 | BUG_ON(cfqd->busy_queues); |
3165 | |
3166 | cfq_log(cfqd, "forced_dispatch=%d", dispatched); |
3167 | return dispatched; |
3168 | } |
3169 | |
3170 | static inline bool cfq_slice_used_soon(struct cfq_data *cfqd, |
3171 | struct cfq_queue *cfqq) |
3172 | { |
3173 | /* the queue hasn't finished any request, can't estimate */ |
3174 | if (cfq_cfqq_slice_new(cfqq)) |
3175 | return true; |
3176 | if (time_after(jiffies + cfqd->cfq_slice_idle * cfqq->dispatched, |
3177 | cfqq->slice_end)) |
3178 | return true; |
3179 | |
3180 | return false; |
3181 | } |
3182 | |
3183 | static bool cfq_may_dispatch(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
3184 | { |
3185 | unsigned int max_dispatch; |
3186 | |
3187 | /* |
3188 | * Drain async requests before we start sync IO |
3189 | */ |
3190 | if (cfq_should_idle(cfqd, cfqq) && cfqd->rq_in_flight[BLK_RW_ASYNC]) |
3191 | return false; |
3192 | |
3193 | /* |
3194 | * If this is an async queue and we have sync IO in flight, let it wait |
3195 | */ |
3196 | if (cfqd->rq_in_flight[BLK_RW_SYNC] && !cfq_cfqq_sync(cfqq)) |
3197 | return false; |
3198 | |
3199 | max_dispatch = max_t(unsigned int, cfqd->cfq_quantum / 2, 1); |
3200 | if (cfq_class_idle(cfqq)) |
3201 | max_dispatch = 1; |
3202 | |
3203 | /* |
3204 | * Does this cfqq already have too much IO in flight? |
3205 | */ |
3206 | if (cfqq->dispatched >= max_dispatch) { |
3207 | bool promote_sync = false; |
3208 | /* |
3209 | * idle queue must always only have a single IO in flight |
3210 | */ |
3211 | if (cfq_class_idle(cfqq)) |
3212 | return false; |
3213 | |
3214 | /* |
3215 | * If there is only one sync queue |
3216 | * we can ignore async queue here and give the sync |
3217 | * queue no dispatch limit. The reason is a sync queue can |
3218 | * preempt async queue, limiting the sync queue doesn't make |
3219 | * sense. This is useful for aiostress test. |
3220 | */ |
3221 | if (cfq_cfqq_sync(cfqq) && cfqd->busy_sync_queues == 1) |
3222 | promote_sync = true; |
3223 | |
3224 | /* |
3225 | * We have other queues, don't allow more IO from this one |
3226 | */ |
3227 | if (cfqd->busy_queues > 1 && cfq_slice_used_soon(cfqd, cfqq) && |
3228 | !promote_sync) |
3229 | return false; |
3230 | |
3231 | /* |
3232 | * Sole queue user, no limit |
3233 | */ |
3234 | if (cfqd->busy_queues == 1 || promote_sync) |
3235 | max_dispatch = -1; |
3236 | else |
3237 | /* |
3238 | * Normally we start throttling cfqq when cfq_quantum/2 |
3239 | * requests have been dispatched. But we can drive |
3240 | * deeper queue depths at the beginning of slice |
3241 | * subjected to upper limit of cfq_quantum. |
3242 | * */ |
3243 | max_dispatch = cfqd->cfq_quantum; |
3244 | } |
3245 | |
3246 | /* |
3247 | * Async queues must wait a bit before being allowed dispatch. |
3248 | * We also ramp up the dispatch depth gradually for async IO, |
3249 | * based on the last sync IO we serviced |
3250 | */ |
3251 | if (!cfq_cfqq_sync(cfqq) && cfqd->cfq_latency) { |
3252 | unsigned long last_sync = jiffies - cfqd->last_delayed_sync; |
3253 | unsigned int depth; |
3254 | |
3255 | depth = last_sync / cfqd->cfq_slice[1]; |
3256 | if (!depth && !cfqq->dispatched) |
3257 | depth = 1; |
3258 | if (depth < max_dispatch) |
3259 | max_dispatch = depth; |
3260 | } |
3261 | |
3262 | /* |
3263 | * If we're below the current max, allow a dispatch |
3264 | */ |
3265 | return cfqq->dispatched < max_dispatch; |
3266 | } |
3267 | |
3268 | /* |
3269 | * Dispatch a request from cfqq, moving them to the request queue |
3270 | * dispatch list. |
3271 | */ |
3272 | static bool cfq_dispatch_request(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
3273 | { |
3274 | struct request *rq; |
3275 | |
3276 | BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list)); |
3277 | |
3278 | if (!cfq_may_dispatch(cfqd, cfqq)) |
3279 | return false; |
3280 | |
3281 | /* |
3282 | * follow expired path, else get first next available |
3283 | */ |
3284 | rq = cfq_check_fifo(cfqq); |
3285 | if (!rq) |
3286 | rq = cfqq->next_rq; |
3287 | |
3288 | /* |
3289 | * insert request into driver dispatch list |
3290 | */ |
3291 | cfq_dispatch_insert(cfqd->queue, rq); |
3292 | |
3293 | if (!cfqd->active_cic) { |
3294 | struct cfq_io_cq *cic = RQ_CIC(rq); |
3295 | |
3296 | atomic_long_inc(&cic->icq.ioc->refcount); |
3297 | cfqd->active_cic = cic; |
3298 | } |
3299 | |
3300 | return true; |
3301 | } |
3302 | |
3303 | /* |
3304 | * Find the cfqq that we need to service and move a request from that to the |
3305 | * dispatch list |
3306 | */ |
3307 | static int cfq_dispatch_requests(struct request_queue *q, int force) |
3308 | { |
3309 | struct cfq_data *cfqd = q->elevator->elevator_data; |
3310 | struct cfq_queue *cfqq; |
3311 | |
3312 | if (!cfqd->busy_queues) |
3313 | return 0; |
3314 | |
3315 | if (unlikely(force)) |
3316 | return cfq_forced_dispatch(cfqd); |
3317 | |
3318 | cfqq = cfq_select_queue(cfqd); |
3319 | if (!cfqq) |
3320 | return 0; |
3321 | |
3322 | /* |
3323 | * Dispatch a request from this cfqq, if it is allowed |
3324 | */ |
3325 | if (!cfq_dispatch_request(cfqd, cfqq)) |
3326 | return 0; |
3327 | |
3328 | cfqq->slice_dispatch++; |
3329 | cfq_clear_cfqq_must_dispatch(cfqq); |
3330 | |
3331 | /* |
3332 | * expire an async queue immediately if it has used up its slice. idle |
3333 | * queue always expire after 1 dispatch round. |
3334 | */ |
3335 | if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) && |
3336 | cfqq->slice_dispatch >= cfq_prio_to_maxrq(cfqd, cfqq)) || |
3337 | cfq_class_idle(cfqq))) { |
3338 | cfqq->slice_end = jiffies + 1; |
3339 | cfq_slice_expired(cfqd, 0); |
3340 | } |
3341 | |
3342 | cfq_log_cfqq(cfqd, cfqq, "dispatched a request"); |
3343 | return 1; |
3344 | } |
3345 | |
3346 | /* |
3347 | * task holds one reference to the queue, dropped when task exits. each rq |
3348 | * in-flight on this queue also holds a reference, dropped when rq is freed. |
3349 | * |
3350 | * Each cfq queue took a reference on the parent group. Drop it now. |
3351 | * queue lock must be held here. |
3352 | */ |
3353 | static void cfq_put_queue(struct cfq_queue *cfqq) |
3354 | { |
3355 | struct cfq_data *cfqd = cfqq->cfqd; |
3356 | struct cfq_group *cfqg; |
3357 | |
3358 | BUG_ON(cfqq->ref <= 0); |
3359 | |
3360 | cfqq->ref--; |
3361 | if (cfqq->ref) |
3362 | return; |
3363 | |
3364 | cfq_log_cfqq(cfqd, cfqq, "put_queue"); |
3365 | BUG_ON(rb_first(&cfqq->sort_list)); |
3366 | BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]); |
3367 | cfqg = cfqq->cfqg; |
3368 | |
3369 | if (unlikely(cfqd->active_queue == cfqq)) { |
3370 | __cfq_slice_expired(cfqd, cfqq, 0); |
3371 | cfq_schedule_dispatch(cfqd); |
3372 | } |
3373 | |
3374 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
3375 | kmem_cache_free(cfq_pool, cfqq); |
3376 | cfqg_put(cfqg); |
3377 | } |
3378 | |
3379 | static void cfq_put_cooperator(struct cfq_queue *cfqq) |
3380 | { |
3381 | struct cfq_queue *__cfqq, *next; |
3382 | |
3383 | /* |
3384 | * If this queue was scheduled to merge with another queue, be |
3385 | * sure to drop the reference taken on that queue (and others in |
3386 | * the merge chain). See cfq_setup_merge and cfq_merge_cfqqs. |
3387 | */ |
3388 | __cfqq = cfqq->new_cfqq; |
3389 | while (__cfqq) { |
3390 | if (__cfqq == cfqq) { |
3391 | WARN(1, "cfqq->new_cfqq loop detected\n"); |
3392 | break; |
3393 | } |
3394 | next = __cfqq->new_cfqq; |
3395 | cfq_put_queue(__cfqq); |
3396 | __cfqq = next; |
3397 | } |
3398 | } |
3399 | |
3400 | static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
3401 | { |
3402 | if (unlikely(cfqq == cfqd->active_queue)) { |
3403 | __cfq_slice_expired(cfqd, cfqq, 0); |
3404 | cfq_schedule_dispatch(cfqd); |
3405 | } |
3406 | |
3407 | cfq_put_cooperator(cfqq); |
3408 | |
3409 | cfq_put_queue(cfqq); |
3410 | } |
3411 | |
3412 | static void cfq_init_icq(struct io_cq *icq) |
3413 | { |
3414 | struct cfq_io_cq *cic = icq_to_cic(icq); |
3415 | |
3416 | cic->ttime.last_end_request = jiffies; |
3417 | } |
3418 | |
3419 | static void cfq_exit_icq(struct io_cq *icq) |
3420 | { |
3421 | struct cfq_io_cq *cic = icq_to_cic(icq); |
3422 | struct cfq_data *cfqd = cic_to_cfqd(cic); |
3423 | |
3424 | if (cic->cfqq[BLK_RW_ASYNC]) { |
3425 | cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_ASYNC]); |
3426 | cic->cfqq[BLK_RW_ASYNC] = NULL; |
3427 | } |
3428 | |
3429 | if (cic->cfqq[BLK_RW_SYNC]) { |
3430 | cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_SYNC]); |
3431 | cic->cfqq[BLK_RW_SYNC] = NULL; |
3432 | } |
3433 | } |
3434 | |
3435 | static void cfq_init_prio_data(struct cfq_queue *cfqq, struct cfq_io_cq *cic) |
3436 | { |
3437 | struct task_struct *tsk = current; |
3438 | int ioprio_class; |
3439 | |
3440 | if (!cfq_cfqq_prio_changed(cfqq)) |
3441 | return; |
3442 | |
3443 | ioprio_class = IOPRIO_PRIO_CLASS(cic->ioprio); |
3444 | switch (ioprio_class) { |
3445 | default: |
3446 | printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class); |
3447 | case IOPRIO_CLASS_NONE: |
3448 | /* |
3449 | * no prio set, inherit CPU scheduling settings |
3450 | */ |
3451 | cfqq->ioprio = task_nice_ioprio(tsk); |
3452 | cfqq->ioprio_class = task_nice_ioclass(tsk); |
3453 | break; |
3454 | case IOPRIO_CLASS_RT: |
3455 | cfqq->ioprio = IOPRIO_PRIO_DATA(cic->ioprio); |
3456 | cfqq->ioprio_class = IOPRIO_CLASS_RT; |
3457 | break; |
3458 | case IOPRIO_CLASS_BE: |
3459 | cfqq->ioprio = IOPRIO_PRIO_DATA(cic->ioprio); |
3460 | cfqq->ioprio_class = IOPRIO_CLASS_BE; |
3461 | break; |
3462 | case IOPRIO_CLASS_IDLE: |
3463 | cfqq->ioprio_class = IOPRIO_CLASS_IDLE; |
3464 | cfqq->ioprio = 7; |
3465 | cfq_clear_cfqq_idle_window(cfqq); |
3466 | break; |
3467 | } |
3468 | |
3469 | /* |
3470 | * keep track of original prio settings in case we have to temporarily |
3471 | * elevate the priority of this queue |
3472 | */ |
3473 | cfqq->org_ioprio = cfqq->ioprio; |
3474 | cfq_clear_cfqq_prio_changed(cfqq); |
3475 | } |
3476 | |
3477 | static void check_ioprio_changed(struct cfq_io_cq *cic, struct bio *bio) |
3478 | { |
3479 | int ioprio = cic->icq.ioc->ioprio; |
3480 | struct cfq_data *cfqd = cic_to_cfqd(cic); |
3481 | struct cfq_queue *cfqq; |
3482 | |
3483 | /* |
3484 | * Check whether ioprio has changed. The condition may trigger |
3485 | * spuriously on a newly created cic but there's no harm. |
3486 | */ |
3487 | if (unlikely(!cfqd) || likely(cic->ioprio == ioprio)) |
3488 | return; |
3489 | |
3490 | cfqq = cic->cfqq[BLK_RW_ASYNC]; |
3491 | if (cfqq) { |
3492 | struct cfq_queue *new_cfqq; |
3493 | new_cfqq = cfq_get_queue(cfqd, BLK_RW_ASYNC, cic, bio, |
3494 | GFP_ATOMIC); |
3495 | if (new_cfqq) { |
3496 | cic->cfqq[BLK_RW_ASYNC] = new_cfqq; |
3497 | cfq_put_queue(cfqq); |
3498 | } |
3499 | } |
3500 | |
3501 | cfqq = cic->cfqq[BLK_RW_SYNC]; |
3502 | if (cfqq) |
3503 | cfq_mark_cfqq_prio_changed(cfqq); |
3504 | |
3505 | cic->ioprio = ioprio; |
3506 | } |
3507 | |
3508 | static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
3509 | pid_t pid, bool is_sync) |
3510 | { |
3511 | RB_CLEAR_NODE(&cfqq->rb_node); |
3512 | RB_CLEAR_NODE(&cfqq->p_node); |
3513 | INIT_LIST_HEAD(&cfqq->fifo); |
3514 | |
3515 | cfqq->ref = 0; |
3516 | cfqq->cfqd = cfqd; |
3517 | |
3518 | cfq_mark_cfqq_prio_changed(cfqq); |
3519 | |
3520 | if (is_sync) { |
3521 | if (!cfq_class_idle(cfqq)) |
3522 | cfq_mark_cfqq_idle_window(cfqq); |
3523 | cfq_mark_cfqq_sync(cfqq); |
3524 | } |
3525 | cfqq->pid = pid; |
3526 | } |
3527 | |
3528 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
3529 | static void check_blkcg_changed(struct cfq_io_cq *cic, struct bio *bio) |
3530 | { |
3531 | struct cfq_data *cfqd = cic_to_cfqd(cic); |
3532 | struct cfq_queue *sync_cfqq; |
3533 | uint64_t id; |
3534 | |
3535 | rcu_read_lock(); |
3536 | id = bio_blkcg(bio)->id; |
3537 | rcu_read_unlock(); |
3538 | |
3539 | /* |
3540 | * Check whether blkcg has changed. The condition may trigger |
3541 | * spuriously on a newly created cic but there's no harm. |
3542 | */ |
3543 | if (unlikely(!cfqd) || likely(cic->blkcg_id == id)) |
3544 | return; |
3545 | |
3546 | sync_cfqq = cic_to_cfqq(cic, 1); |
3547 | if (sync_cfqq) { |
3548 | /* |
3549 | * Drop reference to sync queue. A new sync queue will be |
3550 | * assigned in new group upon arrival of a fresh request. |
3551 | */ |
3552 | cfq_log_cfqq(cfqd, sync_cfqq, "changed cgroup"); |
3553 | cic_set_cfqq(cic, NULL, 1); |
3554 | cfq_put_queue(sync_cfqq); |
3555 | } |
3556 | |
3557 | cic->blkcg_id = id; |
3558 | } |
3559 | #else |
3560 | static inline void check_blkcg_changed(struct cfq_io_cq *cic, struct bio *bio) { } |
3561 | #endif /* CONFIG_CFQ_GROUP_IOSCHED */ |
3562 | |
3563 | static struct cfq_queue * |
3564 | cfq_find_alloc_queue(struct cfq_data *cfqd, bool is_sync, struct cfq_io_cq *cic, |
3565 | struct bio *bio, gfp_t gfp_mask) |
3566 | { |
3567 | struct blkcg *blkcg; |
3568 | struct cfq_queue *cfqq, *new_cfqq = NULL; |
3569 | struct cfq_group *cfqg; |
3570 | |
3571 | retry: |
3572 | rcu_read_lock(); |
3573 | |
3574 | blkcg = bio_blkcg(bio); |
3575 | cfqg = cfq_lookup_create_cfqg(cfqd, blkcg); |
3576 | cfqq = cic_to_cfqq(cic, is_sync); |
3577 | |
3578 | /* |
3579 | * Always try a new alloc if we fell back to the OOM cfqq |
3580 | * originally, since it should just be a temporary situation. |
3581 | */ |
3582 | if (!cfqq || cfqq == &cfqd->oom_cfqq) { |
3583 | cfqq = NULL; |
3584 | if (new_cfqq) { |
3585 | cfqq = new_cfqq; |
3586 | new_cfqq = NULL; |
3587 | } else if (gfp_mask & __GFP_WAIT) { |
3588 | rcu_read_unlock(); |
3589 | spin_unlock_irq(cfqd->queue->queue_lock); |
3590 | new_cfqq = kmem_cache_alloc_node(cfq_pool, |
3591 | gfp_mask | __GFP_ZERO, |
3592 | cfqd->queue->node); |
3593 | spin_lock_irq(cfqd->queue->queue_lock); |
3594 | if (new_cfqq) |
3595 | goto retry; |
3596 | else |
3597 | return &cfqd->oom_cfqq; |
3598 | } else { |
3599 | cfqq = kmem_cache_alloc_node(cfq_pool, |
3600 | gfp_mask | __GFP_ZERO, |
3601 | cfqd->queue->node); |
3602 | } |
3603 | |
3604 | if (cfqq) { |
3605 | cfq_init_cfqq(cfqd, cfqq, current->pid, is_sync); |
3606 | cfq_init_prio_data(cfqq, cic); |
3607 | cfq_link_cfqq_cfqg(cfqq, cfqg); |
3608 | cfq_log_cfqq(cfqd, cfqq, "alloced"); |
3609 | } else |
3610 | cfqq = &cfqd->oom_cfqq; |
3611 | } |
3612 | |
3613 | if (new_cfqq) |
3614 | kmem_cache_free(cfq_pool, new_cfqq); |
3615 | |
3616 | rcu_read_unlock(); |
3617 | return cfqq; |
3618 | } |
3619 | |
3620 | static struct cfq_queue ** |
3621 | cfq_async_queue_prio(struct cfq_data *cfqd, int ioprio_class, int ioprio) |
3622 | { |
3623 | switch (ioprio_class) { |
3624 | case IOPRIO_CLASS_RT: |
3625 | return &cfqd->async_cfqq[0][ioprio]; |
3626 | case IOPRIO_CLASS_NONE: |
3627 | ioprio = IOPRIO_NORM; |
3628 | /* fall through */ |
3629 | case IOPRIO_CLASS_BE: |
3630 | return &cfqd->async_cfqq[1][ioprio]; |
3631 | case IOPRIO_CLASS_IDLE: |
3632 | return &cfqd->async_idle_cfqq; |
3633 | default: |
3634 | BUG(); |
3635 | } |
3636 | } |
3637 | |
3638 | static struct cfq_queue * |
3639 | cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct cfq_io_cq *cic, |
3640 | struct bio *bio, gfp_t gfp_mask) |
3641 | { |
3642 | const int ioprio_class = IOPRIO_PRIO_CLASS(cic->ioprio); |
3643 | const int ioprio = IOPRIO_PRIO_DATA(cic->ioprio); |
3644 | struct cfq_queue **async_cfqq = NULL; |
3645 | struct cfq_queue *cfqq = NULL; |
3646 | |
3647 | if (!is_sync) { |
3648 | async_cfqq = cfq_async_queue_prio(cfqd, ioprio_class, ioprio); |
3649 | cfqq = *async_cfqq; |
3650 | } |
3651 | |
3652 | if (!cfqq) |
3653 | cfqq = cfq_find_alloc_queue(cfqd, is_sync, cic, bio, gfp_mask); |
3654 | |
3655 | /* |
3656 | * pin the queue now that it's allocated, scheduler exit will prune it |
3657 | */ |
3658 | if (!is_sync && !(*async_cfqq)) { |
3659 | cfqq->ref++; |
3660 | *async_cfqq = cfqq; |
3661 | } |
3662 | |
3663 | cfqq->ref++; |
3664 | return cfqq; |
3665 | } |
3666 | |
3667 | static void |
3668 | __cfq_update_io_thinktime(struct cfq_ttime *ttime, unsigned long slice_idle) |
3669 | { |
3670 | unsigned long elapsed = jiffies - ttime->last_end_request; |
3671 | elapsed = min(elapsed, 2UL * slice_idle); |
3672 | |
3673 | ttime->ttime_samples = (7*ttime->ttime_samples + 256) / 8; |
3674 | ttime->ttime_total = (7*ttime->ttime_total + 256*elapsed) / 8; |
3675 | ttime->ttime_mean = (ttime->ttime_total + 128) / ttime->ttime_samples; |
3676 | } |
3677 | |
3678 | static void |
3679 | cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
3680 | struct cfq_io_cq *cic) |
3681 | { |
3682 | if (cfq_cfqq_sync(cfqq)) { |
3683 | __cfq_update_io_thinktime(&cic->ttime, cfqd->cfq_slice_idle); |
3684 | __cfq_update_io_thinktime(&cfqq->service_tree->ttime, |
3685 | cfqd->cfq_slice_idle); |
3686 | } |
3687 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
3688 | __cfq_update_io_thinktime(&cfqq->cfqg->ttime, cfqd->cfq_group_idle); |
3689 | #endif |
3690 | } |
3691 | |
3692 | static void |
3693 | cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
3694 | struct request *rq) |
3695 | { |
3696 | sector_t sdist = 0; |
3697 | sector_t n_sec = blk_rq_sectors(rq); |
3698 | if (cfqq->last_request_pos) { |
3699 | if (cfqq->last_request_pos < blk_rq_pos(rq)) |
3700 | sdist = blk_rq_pos(rq) - cfqq->last_request_pos; |
3701 | else |
3702 | sdist = cfqq->last_request_pos - blk_rq_pos(rq); |
3703 | } |
3704 | |
3705 | cfqq->seek_history <<= 1; |
3706 | if (blk_queue_nonrot(cfqd->queue)) |
3707 | cfqq->seek_history |= (n_sec < CFQQ_SECT_THR_NONROT); |
3708 | else |
3709 | cfqq->seek_history |= (sdist > CFQQ_SEEK_THR); |
3710 | } |
3711 | |
3712 | /* |
3713 | * Disable idle window if the process thinks too long or seeks so much that |
3714 | * it doesn't matter |
3715 | */ |
3716 | static void |
3717 | cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
3718 | struct cfq_io_cq *cic) |
3719 | { |
3720 | int old_idle, enable_idle; |
3721 | |
3722 | /* |
3723 | * Don't idle for async or idle io prio class |
3724 | */ |
3725 | if (!cfq_cfqq_sync(cfqq) || cfq_class_idle(cfqq)) |
3726 | return; |
3727 | |
3728 | enable_idle = old_idle = cfq_cfqq_idle_window(cfqq); |
3729 | |
3730 | if (cfqq->queued[0] + cfqq->queued[1] >= 4) |
3731 | cfq_mark_cfqq_deep(cfqq); |
3732 | |
3733 | if (cfqq->next_rq && (cfqq->next_rq->cmd_flags & REQ_NOIDLE)) |
3734 | enable_idle = 0; |
3735 | else if (!atomic_read(&cic->icq.ioc->active_ref) || |
3736 | !cfqd->cfq_slice_idle || |
3737 | (!cfq_cfqq_deep(cfqq) && CFQQ_SEEKY(cfqq))) |
3738 | enable_idle = 0; |
3739 | else if (sample_valid(cic->ttime.ttime_samples)) { |
3740 | if (cic->ttime.ttime_mean > cfqd->cfq_slice_idle) |
3741 | enable_idle = 0; |
3742 | else |
3743 | enable_idle = 1; |
3744 | } |
3745 | |
3746 | if (old_idle != enable_idle) { |
3747 | cfq_log_cfqq(cfqd, cfqq, "idle=%d", enable_idle); |
3748 | if (enable_idle) |
3749 | cfq_mark_cfqq_idle_window(cfqq); |
3750 | else |
3751 | cfq_clear_cfqq_idle_window(cfqq); |
3752 | } |
3753 | } |
3754 | |
3755 | /* |
3756 | * Check if new_cfqq should preempt the currently active queue. Return 0 for |
3757 | * no or if we aren't sure, a 1 will cause a preempt. |
3758 | */ |
3759 | static bool |
3760 | cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, |
3761 | struct request *rq) |
3762 | { |
3763 | struct cfq_queue *cfqq; |
3764 | |
3765 | cfqq = cfqd->active_queue; |
3766 | if (!cfqq) |
3767 | return false; |
3768 | |
3769 | if (cfq_class_idle(new_cfqq)) |
3770 | return false; |
3771 | |
3772 | if (cfq_class_idle(cfqq)) |
3773 | return true; |
3774 | |
3775 | /* |
3776 | * Don't allow a non-RT request to preempt an ongoing RT cfqq timeslice. |
3777 | */ |
3778 | if (cfq_class_rt(cfqq) && !cfq_class_rt(new_cfqq)) |
3779 | return false; |
3780 | |
3781 | /* |
3782 | * if the new request is sync, but the currently running queue is |
3783 | * not, let the sync request have priority. |
3784 | */ |
3785 | if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq)) |
3786 | return true; |
3787 | |
3788 | if (new_cfqq->cfqg != cfqq->cfqg) |
3789 | return false; |
3790 | |
3791 | if (cfq_slice_used(cfqq)) |
3792 | return true; |
3793 | |
3794 | /* Allow preemption only if we are idling on sync-noidle tree */ |
3795 | if (cfqd->serving_wl_type == SYNC_NOIDLE_WORKLOAD && |
3796 | cfqq_type(new_cfqq) == SYNC_NOIDLE_WORKLOAD && |
3797 | new_cfqq->service_tree->count == 2 && |
3798 | RB_EMPTY_ROOT(&cfqq->sort_list)) |
3799 | return true; |
3800 | |
3801 | /* |
3802 | * So both queues are sync. Let the new request get disk time if |
3803 | * it's a metadata request and the current queue is doing regular IO. |
3804 | */ |
3805 | if ((rq->cmd_flags & REQ_PRIO) && !cfqq->prio_pending) |
3806 | return true; |
3807 | |
3808 | /* |
3809 | * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice. |
3810 | */ |
3811 | if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq)) |
3812 | return true; |
3813 | |
3814 | /* An idle queue should not be idle now for some reason */ |
3815 | if (RB_EMPTY_ROOT(&cfqq->sort_list) && !cfq_should_idle(cfqd, cfqq)) |
3816 | return true; |
3817 | |
3818 | if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq)) |
3819 | return false; |
3820 | |
3821 | /* |
3822 | * if this request is as-good as one we would expect from the |
3823 | * current cfqq, let it preempt |
3824 | */ |
3825 | if (cfq_rq_close(cfqd, cfqq, rq)) |
3826 | return true; |
3827 | |
3828 | return false; |
3829 | } |
3830 | |
3831 | /* |
3832 | * cfqq preempts the active queue. if we allowed preempt with no slice left, |
3833 | * let it have half of its nominal slice. |
3834 | */ |
3835 | static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
3836 | { |
3837 | enum wl_type_t old_type = cfqq_type(cfqd->active_queue); |
3838 | |
3839 | cfq_log_cfqq(cfqd, cfqq, "preempt"); |
3840 | cfq_slice_expired(cfqd, 1); |
3841 | |
3842 | /* |
3843 | * workload type is changed, don't save slice, otherwise preempt |
3844 | * doesn't happen |
3845 | */ |
3846 | if (old_type != cfqq_type(cfqq)) |
3847 | cfqq->cfqg->saved_wl_slice = 0; |
3848 | |
3849 | /* |
3850 | * Put the new queue at the front of the of the current list, |
3851 | * so we know that it will be selected next. |
3852 | */ |
3853 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
3854 | |
3855 | cfq_service_tree_add(cfqd, cfqq, 1); |
3856 | |
3857 | cfqq->slice_end = 0; |
3858 | cfq_mark_cfqq_slice_new(cfqq); |
3859 | } |
3860 | |
3861 | /* |
3862 | * Called when a new fs request (rq) is added (to cfqq). Check if there's |
3863 | * something we should do about it |
3864 | */ |
3865 | static void |
3866 | cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
3867 | struct request *rq) |
3868 | { |
3869 | struct cfq_io_cq *cic = RQ_CIC(rq); |
3870 | |
3871 | cfqd->rq_queued++; |
3872 | if (rq->cmd_flags & REQ_PRIO) |
3873 | cfqq->prio_pending++; |
3874 | |
3875 | cfq_update_io_thinktime(cfqd, cfqq, cic); |
3876 | cfq_update_io_seektime(cfqd, cfqq, rq); |
3877 | cfq_update_idle_window(cfqd, cfqq, cic); |
3878 | |
3879 | cfqq->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq); |
3880 | |
3881 | if (cfqq == cfqd->active_queue) { |
3882 | /* |
3883 | * Remember that we saw a request from this process, but |
3884 | * don't start queuing just yet. Otherwise we risk seeing lots |
3885 | * of tiny requests, because we disrupt the normal plugging |
3886 | * and merging. If the request is already larger than a single |
3887 | * page, let it rip immediately. For that case we assume that |
3888 | * merging is already done. Ditto for a busy system that |
3889 | * has other work pending, don't risk delaying until the |
3890 | * idle timer unplug to continue working. |
3891 | */ |
3892 | if (cfq_cfqq_wait_request(cfqq)) { |
3893 | if (blk_rq_bytes(rq) > PAGE_CACHE_SIZE || |
3894 | cfqd->busy_queues > 1) { |
3895 | cfq_del_timer(cfqd, cfqq); |
3896 | cfq_clear_cfqq_wait_request(cfqq); |
3897 | __blk_run_queue(cfqd->queue); |
3898 | } else { |
3899 | cfqg_stats_update_idle_time(cfqq->cfqg); |
3900 | cfq_mark_cfqq_must_dispatch(cfqq); |
3901 | } |
3902 | } |
3903 | } else if (cfq_should_preempt(cfqd, cfqq, rq)) { |
3904 | /* |
3905 | * not the active queue - expire current slice if it is |
3906 | * idle and has expired it's mean thinktime or this new queue |
3907 | * has some old slice time left and is of higher priority or |
3908 | * this new queue is RT and the current one is BE |
3909 | */ |
3910 | cfq_preempt_queue(cfqd, cfqq); |
3911 | __blk_run_queue(cfqd->queue); |
3912 | } |
3913 | } |
3914 | |
3915 | static void cfq_insert_request(struct request_queue *q, struct request *rq) |
3916 | { |
3917 | struct cfq_data *cfqd = q->elevator->elevator_data; |
3918 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
3919 | |
3920 | cfq_log_cfqq(cfqd, cfqq, "insert_request"); |
3921 | cfq_init_prio_data(cfqq, RQ_CIC(rq)); |
3922 | |
3923 | rq_set_fifo_time(rq, jiffies + cfqd->cfq_fifo_expire[rq_is_sync(rq)]); |
3924 | list_add_tail(&rq->queuelist, &cfqq->fifo); |
3925 | cfq_add_rq_rb(rq); |
3926 | cfqg_stats_update_io_add(RQ_CFQG(rq), cfqd->serving_group, |
3927 | rq->cmd_flags); |
3928 | cfq_rq_enqueued(cfqd, cfqq, rq); |
3929 | } |
3930 | |
3931 | /* |
3932 | * Update hw_tag based on peak queue depth over 50 samples under |
3933 | * sufficient load. |
3934 | */ |
3935 | static void cfq_update_hw_tag(struct cfq_data *cfqd) |
3936 | { |
3937 | struct cfq_queue *cfqq = cfqd->active_queue; |
3938 | |
3939 | if (cfqd->rq_in_driver > cfqd->hw_tag_est_depth) |
3940 | cfqd->hw_tag_est_depth = cfqd->rq_in_driver; |
3941 | |
3942 | if (cfqd->hw_tag == 1) |
3943 | return; |
3944 | |
3945 | if (cfqd->rq_queued <= CFQ_HW_QUEUE_MIN && |
3946 | cfqd->rq_in_driver <= CFQ_HW_QUEUE_MIN) |
3947 | return; |
3948 | |
3949 | /* |
3950 | * If active queue hasn't enough requests and can idle, cfq might not |
3951 | * dispatch sufficient requests to hardware. Don't zero hw_tag in this |
3952 | * case |
3953 | */ |
3954 | if (cfqq && cfq_cfqq_idle_window(cfqq) && |
3955 | cfqq->dispatched + cfqq->queued[0] + cfqq->queued[1] < |
3956 | CFQ_HW_QUEUE_MIN && cfqd->rq_in_driver < CFQ_HW_QUEUE_MIN) |
3957 | return; |
3958 | |
3959 | if (cfqd->hw_tag_samples++ < 50) |
3960 | return; |
3961 | |
3962 | if (cfqd->hw_tag_est_depth >= CFQ_HW_QUEUE_MIN) |
3963 | cfqd->hw_tag = 1; |
3964 | else |
3965 | cfqd->hw_tag = 0; |
3966 | } |
3967 | |
3968 | static bool cfq_should_wait_busy(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
3969 | { |
3970 | struct cfq_io_cq *cic = cfqd->active_cic; |
3971 | |
3972 | /* If the queue already has requests, don't wait */ |
3973 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
3974 | return false; |
3975 | |
3976 | /* If there are other queues in the group, don't wait */ |
3977 | if (cfqq->cfqg->nr_cfqq > 1) |
3978 | return false; |
3979 | |
3980 | /* the only queue in the group, but think time is big */ |
3981 | if (cfq_io_thinktime_big(cfqd, &cfqq->cfqg->ttime, true)) |
3982 | return false; |
3983 | |
3984 | if (cfq_slice_used(cfqq)) |
3985 | return true; |
3986 | |
3987 | /* if slice left is less than think time, wait busy */ |
3988 | if (cic && sample_valid(cic->ttime.ttime_samples) |
3989 | && (cfqq->slice_end - jiffies < cic->ttime.ttime_mean)) |
3990 | return true; |
3991 | |
3992 | /* |
3993 | * If think times is less than a jiffy than ttime_mean=0 and above |
3994 | * will not be true. It might happen that slice has not expired yet |
3995 | * but will expire soon (4-5 ns) during select_queue(). To cover the |
3996 | * case where think time is less than a jiffy, mark the queue wait |
3997 | * busy if only 1 jiffy is left in the slice. |
3998 | */ |
3999 | if (cfqq->slice_end - jiffies == 1) |
4000 | return true; |
4001 | |
4002 | return false; |
4003 | } |
4004 | |
4005 | static void cfq_completed_request(struct request_queue *q, struct request *rq) |
4006 | { |
4007 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
4008 | struct cfq_data *cfqd = cfqq->cfqd; |
4009 | const int sync = rq_is_sync(rq); |
4010 | unsigned long now; |
4011 | |
4012 | now = jiffies; |
4013 | cfq_log_cfqq(cfqd, cfqq, "complete rqnoidle %d", |
4014 | !!(rq->cmd_flags & REQ_NOIDLE)); |
4015 | |
4016 | cfq_update_hw_tag(cfqd); |
4017 | |
4018 | WARN_ON(!cfqd->rq_in_driver); |
4019 | WARN_ON(!cfqq->dispatched); |
4020 | cfqd->rq_in_driver--; |
4021 | cfqq->dispatched--; |
4022 | (RQ_CFQG(rq))->dispatched--; |
4023 | cfqg_stats_update_completion(cfqq->cfqg, rq_start_time_ns(rq), |
4024 | rq_io_start_time_ns(rq), rq->cmd_flags); |
4025 | |
4026 | cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]--; |
4027 | |
4028 | if (sync) { |
4029 | struct cfq_rb_root *st; |
4030 | |
4031 | RQ_CIC(rq)->ttime.last_end_request = now; |
4032 | |
4033 | if (cfq_cfqq_on_rr(cfqq)) |
4034 | st = cfqq->service_tree; |
4035 | else |
4036 | st = st_for(cfqq->cfqg, cfqq_class(cfqq), |
4037 | cfqq_type(cfqq)); |
4038 | |
4039 | st->ttime.last_end_request = now; |
4040 | if (!time_after(rq->start_time + cfqd->cfq_fifo_expire[1], now)) |
4041 | cfqd->last_delayed_sync = now; |
4042 | } |
4043 | |
4044 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
4045 | cfqq->cfqg->ttime.last_end_request = now; |
4046 | #endif |
4047 | |
4048 | /* |
4049 | * If this is the active queue, check if it needs to be expired, |
4050 | * or if we want to idle in case it has no pending requests. |
4051 | */ |
4052 | if (cfqd->active_queue == cfqq) { |
4053 | const bool cfqq_empty = RB_EMPTY_ROOT(&cfqq->sort_list); |
4054 | |
4055 | if (cfq_cfqq_slice_new(cfqq)) { |
4056 | cfq_set_prio_slice(cfqd, cfqq); |
4057 | cfq_clear_cfqq_slice_new(cfqq); |
4058 | } |
4059 | |
4060 | /* |
4061 | * Should we wait for next request to come in before we expire |
4062 | * the queue. |
4063 | */ |
4064 | if (cfq_should_wait_busy(cfqd, cfqq)) { |
4065 | unsigned long extend_sl = cfqd->cfq_slice_idle; |
4066 | if (!cfqd->cfq_slice_idle) |
4067 | extend_sl = cfqd->cfq_group_idle; |
4068 | cfqq->slice_end = jiffies + extend_sl; |
4069 | cfq_mark_cfqq_wait_busy(cfqq); |
4070 | cfq_log_cfqq(cfqd, cfqq, "will busy wait"); |
4071 | } |
4072 | |
4073 | /* |
4074 | * Idling is not enabled on: |
4075 | * - expired queues |
4076 | * - idle-priority queues |
4077 | * - async queues |
4078 | * - queues with still some requests queued |
4079 | * - when there is a close cooperator |
4080 | */ |
4081 | if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq)) |
4082 | cfq_slice_expired(cfqd, 1); |
4083 | else if (sync && cfqq_empty && |
4084 | !cfq_close_cooperator(cfqd, cfqq)) { |
4085 | cfq_arm_slice_timer(cfqd); |
4086 | } |
4087 | } |
4088 | |
4089 | if (!cfqd->rq_in_driver) |
4090 | cfq_schedule_dispatch(cfqd); |
4091 | } |
4092 | |
4093 | static inline int __cfq_may_queue(struct cfq_queue *cfqq) |
4094 | { |
4095 | if (cfq_cfqq_wait_request(cfqq) && !cfq_cfqq_must_alloc_slice(cfqq)) { |
4096 | cfq_mark_cfqq_must_alloc_slice(cfqq); |
4097 | return ELV_MQUEUE_MUST; |
4098 | } |
4099 | |
4100 | return ELV_MQUEUE_MAY; |
4101 | } |
4102 | |
4103 | static int cfq_may_queue(struct request_queue *q, int rw) |
4104 | { |
4105 | struct cfq_data *cfqd = q->elevator->elevator_data; |
4106 | struct task_struct *tsk = current; |
4107 | struct cfq_io_cq *cic; |
4108 | struct cfq_queue *cfqq; |
4109 | |
4110 | /* |
4111 | * don't force setup of a queue from here, as a call to may_queue |
4112 | * does not necessarily imply that a request actually will be queued. |
4113 | * so just lookup a possibly existing queue, or return 'may queue' |
4114 | * if that fails |
4115 | */ |
4116 | cic = cfq_cic_lookup(cfqd, tsk->io_context); |
4117 | if (!cic) |
4118 | return ELV_MQUEUE_MAY; |
4119 | |
4120 | cfqq = cic_to_cfqq(cic, rw_is_sync(rw)); |
4121 | if (cfqq) { |
4122 | cfq_init_prio_data(cfqq, cic); |
4123 | |
4124 | return __cfq_may_queue(cfqq); |
4125 | } |
4126 | |
4127 | return ELV_MQUEUE_MAY; |
4128 | } |
4129 | |
4130 | /* |
4131 | * queue lock held here |
4132 | */ |
4133 | static void cfq_put_request(struct request *rq) |
4134 | { |
4135 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
4136 | |
4137 | if (cfqq) { |
4138 | const int rw = rq_data_dir(rq); |
4139 | |
4140 | BUG_ON(!cfqq->allocated[rw]); |
4141 | cfqq->allocated[rw]--; |
4142 | |
4143 | /* Put down rq reference on cfqg */ |
4144 | cfqg_put(RQ_CFQG(rq)); |
4145 | rq->elv.priv[0] = NULL; |
4146 | rq->elv.priv[1] = NULL; |
4147 | |
4148 | cfq_put_queue(cfqq); |
4149 | } |
4150 | } |
4151 | |
4152 | static struct cfq_queue * |
4153 | cfq_merge_cfqqs(struct cfq_data *cfqd, struct cfq_io_cq *cic, |
4154 | struct cfq_queue *cfqq) |
4155 | { |
4156 | cfq_log_cfqq(cfqd, cfqq, "merging with queue %p", cfqq->new_cfqq); |
4157 | cic_set_cfqq(cic, cfqq->new_cfqq, 1); |
4158 | cfq_mark_cfqq_coop(cfqq->new_cfqq); |
4159 | cfq_put_queue(cfqq); |
4160 | return cic_to_cfqq(cic, 1); |
4161 | } |
4162 | |
4163 | /* |
4164 | * Returns NULL if a new cfqq should be allocated, or the old cfqq if this |
4165 | * was the last process referring to said cfqq. |
4166 | */ |
4167 | static struct cfq_queue * |
4168 | split_cfqq(struct cfq_io_cq *cic, struct cfq_queue *cfqq) |
4169 | { |
4170 | if (cfqq_process_refs(cfqq) == 1) { |
4171 | cfqq->pid = current->pid; |
4172 | cfq_clear_cfqq_coop(cfqq); |
4173 | cfq_clear_cfqq_split_coop(cfqq); |
4174 | return cfqq; |
4175 | } |
4176 | |
4177 | cic_set_cfqq(cic, NULL, 1); |
4178 | |
4179 | cfq_put_cooperator(cfqq); |
4180 | |
4181 | cfq_put_queue(cfqq); |
4182 | return NULL; |
4183 | } |
4184 | /* |
4185 | * Allocate cfq data structures associated with this request. |
4186 | */ |
4187 | static int |
4188 | cfq_set_request(struct request_queue *q, struct request *rq, struct bio *bio, |
4189 | gfp_t gfp_mask) |
4190 | { |
4191 | struct cfq_data *cfqd = q->elevator->elevator_data; |
4192 | struct cfq_io_cq *cic = icq_to_cic(rq->elv.icq); |
4193 | const int rw = rq_data_dir(rq); |
4194 | const bool is_sync = rq_is_sync(rq); |
4195 | struct cfq_queue *cfqq; |
4196 | |
4197 | might_sleep_if(gfp_mask & __GFP_WAIT); |
4198 | |
4199 | spin_lock_irq(q->queue_lock); |
4200 | |
4201 | check_ioprio_changed(cic, bio); |
4202 | check_blkcg_changed(cic, bio); |
4203 | new_queue: |
4204 | cfqq = cic_to_cfqq(cic, is_sync); |
4205 | if (!cfqq || cfqq == &cfqd->oom_cfqq) { |
4206 | cfqq = cfq_get_queue(cfqd, is_sync, cic, bio, gfp_mask); |
4207 | cic_set_cfqq(cic, cfqq, is_sync); |
4208 | } else { |
4209 | /* |
4210 | * If the queue was seeky for too long, break it apart. |
4211 | */ |
4212 | if (cfq_cfqq_coop(cfqq) && cfq_cfqq_split_coop(cfqq)) { |
4213 | cfq_log_cfqq(cfqd, cfqq, "breaking apart cfqq"); |
4214 | cfqq = split_cfqq(cic, cfqq); |
4215 | if (!cfqq) |
4216 | goto new_queue; |
4217 | } |
4218 | |
4219 | /* |
4220 | * Check to see if this queue is scheduled to merge with |
4221 | * another, closely cooperating queue. The merging of |
4222 | * queues happens here as it must be done in process context. |
4223 | * The reference on new_cfqq was taken in merge_cfqqs. |
4224 | */ |
4225 | if (cfqq->new_cfqq) |
4226 | cfqq = cfq_merge_cfqqs(cfqd, cic, cfqq); |
4227 | } |
4228 | |
4229 | cfqq->allocated[rw]++; |
4230 | |
4231 | cfqq->ref++; |
4232 | cfqg_get(cfqq->cfqg); |
4233 | rq->elv.priv[0] = cfqq; |
4234 | rq->elv.priv[1] = cfqq->cfqg; |
4235 | spin_unlock_irq(q->queue_lock); |
4236 | return 0; |
4237 | } |
4238 | |
4239 | static void cfq_kick_queue(struct work_struct *work) |
4240 | { |
4241 | struct cfq_data *cfqd = |
4242 | container_of(work, struct cfq_data, unplug_work); |
4243 | struct request_queue *q = cfqd->queue; |
4244 | |
4245 | spin_lock_irq(q->queue_lock); |
4246 | __blk_run_queue(cfqd->queue); |
4247 | spin_unlock_irq(q->queue_lock); |
4248 | } |
4249 | |
4250 | /* |
4251 | * Timer running if the active_queue is currently idling inside its time slice |
4252 | */ |
4253 | static void cfq_idle_slice_timer(unsigned long data) |
4254 | { |
4255 | struct cfq_data *cfqd = (struct cfq_data *) data; |
4256 | struct cfq_queue *cfqq; |
4257 | unsigned long flags; |
4258 | int timed_out = 1; |
4259 | |
4260 | cfq_log(cfqd, "idle timer fired"); |
4261 | |
4262 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); |
4263 | |
4264 | cfqq = cfqd->active_queue; |
4265 | if (cfqq) { |
4266 | timed_out = 0; |
4267 | |
4268 | /* |
4269 | * We saw a request before the queue expired, let it through |
4270 | */ |
4271 | if (cfq_cfqq_must_dispatch(cfqq)) |
4272 | goto out_kick; |
4273 | |
4274 | /* |
4275 | * expired |
4276 | */ |
4277 | if (cfq_slice_used(cfqq)) |
4278 | goto expire; |
4279 | |
4280 | /* |
4281 | * only expire and reinvoke request handler, if there are |
4282 | * other queues with pending requests |
4283 | */ |
4284 | if (!cfqd->busy_queues) |
4285 | goto out_cont; |
4286 | |
4287 | /* |
4288 | * not expired and it has a request pending, let it dispatch |
4289 | */ |
4290 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
4291 | goto out_kick; |
4292 | |
4293 | /* |
4294 | * Queue depth flag is reset only when the idle didn't succeed |
4295 | */ |
4296 | cfq_clear_cfqq_deep(cfqq); |
4297 | } |
4298 | expire: |
4299 | cfq_slice_expired(cfqd, timed_out); |
4300 | out_kick: |
4301 | cfq_schedule_dispatch(cfqd); |
4302 | out_cont: |
4303 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); |
4304 | } |
4305 | |
4306 | static void cfq_shutdown_timer_wq(struct cfq_data *cfqd) |
4307 | { |
4308 | del_timer_sync(&cfqd->idle_slice_timer); |
4309 | cancel_work_sync(&cfqd->unplug_work); |
4310 | } |
4311 | |
4312 | static void cfq_put_async_queues(struct cfq_data *cfqd) |
4313 | { |
4314 | int i; |
4315 | |
4316 | for (i = 0; i < IOPRIO_BE_NR; i++) { |
4317 | if (cfqd->async_cfqq[0][i]) |
4318 | cfq_put_queue(cfqd->async_cfqq[0][i]); |
4319 | if (cfqd->async_cfqq[1][i]) |
4320 | cfq_put_queue(cfqd->async_cfqq[1][i]); |
4321 | } |
4322 | |
4323 | if (cfqd->async_idle_cfqq) |
4324 | cfq_put_queue(cfqd->async_idle_cfqq); |
4325 | } |
4326 | |
4327 | static void cfq_exit_queue(struct elevator_queue *e) |
4328 | { |
4329 | struct cfq_data *cfqd = e->elevator_data; |
4330 | struct request_queue *q = cfqd->queue; |
4331 | |
4332 | cfq_shutdown_timer_wq(cfqd); |
4333 | |
4334 | spin_lock_irq(q->queue_lock); |
4335 | |
4336 | if (cfqd->active_queue) |
4337 | __cfq_slice_expired(cfqd, cfqd->active_queue, 0); |
4338 | |
4339 | cfq_put_async_queues(cfqd); |
4340 | |
4341 | spin_unlock_irq(q->queue_lock); |
4342 | |
4343 | cfq_shutdown_timer_wq(cfqd); |
4344 | |
4345 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
4346 | blkcg_deactivate_policy(q, &blkcg_policy_cfq); |
4347 | #else |
4348 | kfree(cfqd->root_group); |
4349 | #endif |
4350 | kfree(cfqd); |
4351 | } |
4352 | |
4353 | static int cfq_init_queue(struct request_queue *q) |
4354 | { |
4355 | struct cfq_data *cfqd; |
4356 | struct blkcg_gq *blkg __maybe_unused; |
4357 | int i, ret; |
4358 | |
4359 | cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL | __GFP_ZERO, q->node); |
4360 | if (!cfqd) |
4361 | return -ENOMEM; |
4362 | |
4363 | cfqd->queue = q; |
4364 | q->elevator->elevator_data = cfqd; |
4365 | |
4366 | /* Init root service tree */ |
4367 | cfqd->grp_service_tree = CFQ_RB_ROOT; |
4368 | |
4369 | /* Init root group and prefer root group over other groups by default */ |
4370 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
4371 | ret = blkcg_activate_policy(q, &blkcg_policy_cfq); |
4372 | if (ret) |
4373 | goto out_free; |
4374 | |
4375 | cfqd->root_group = blkg_to_cfqg(q->root_blkg); |
4376 | #else |
4377 | ret = -ENOMEM; |
4378 | cfqd->root_group = kzalloc_node(sizeof(*cfqd->root_group), |
4379 | GFP_KERNEL, cfqd->queue->node); |
4380 | if (!cfqd->root_group) |
4381 | goto out_free; |
4382 | |
4383 | cfq_init_cfqg_base(cfqd->root_group); |
4384 | #endif |
4385 | cfqd->root_group->weight = 2 * CFQ_WEIGHT_DEFAULT; |
4386 | cfqd->root_group->leaf_weight = 2 * CFQ_WEIGHT_DEFAULT; |
4387 | |
4388 | /* |
4389 | * Not strictly needed (since RB_ROOT just clears the node and we |
4390 | * zeroed cfqd on alloc), but better be safe in case someone decides |
4391 | * to add magic to the rb code |
4392 | */ |
4393 | for (i = 0; i < CFQ_PRIO_LISTS; i++) |
4394 | cfqd->prio_trees[i] = RB_ROOT; |
4395 | |
4396 | /* |
4397 | * Our fallback cfqq if cfq_find_alloc_queue() runs into OOM issues. |
4398 | * Grab a permanent reference to it, so that the normal code flow |
4399 | * will not attempt to free it. oom_cfqq is linked to root_group |
4400 | * but shouldn't hold a reference as it'll never be unlinked. Lose |
4401 | * the reference from linking right away. |
4402 | */ |
4403 | cfq_init_cfqq(cfqd, &cfqd->oom_cfqq, 1, 0); |
4404 | cfqd->oom_cfqq.ref++; |
4405 | |
4406 | spin_lock_irq(q->queue_lock); |
4407 | cfq_link_cfqq_cfqg(&cfqd->oom_cfqq, cfqd->root_group); |
4408 | cfqg_put(cfqd->root_group); |
4409 | spin_unlock_irq(q->queue_lock); |
4410 | |
4411 | init_timer(&cfqd->idle_slice_timer); |
4412 | cfqd->idle_slice_timer.function = cfq_idle_slice_timer; |
4413 | cfqd->idle_slice_timer.data = (unsigned long) cfqd; |
4414 | |
4415 | INIT_WORK(&cfqd->unplug_work, cfq_kick_queue); |
4416 | |
4417 | cfqd->cfq_quantum = cfq_quantum; |
4418 | cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; |
4419 | cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; |
4420 | cfqd->cfq_back_max = cfq_back_max; |
4421 | cfqd->cfq_back_penalty = cfq_back_penalty; |
4422 | cfqd->cfq_slice[0] = cfq_slice_async; |
4423 | cfqd->cfq_slice[1] = cfq_slice_sync; |
4424 | cfqd->cfq_target_latency = cfq_target_latency; |
4425 | cfqd->cfq_slice_async_rq = cfq_slice_async_rq; |
4426 | cfqd->cfq_slice_idle = cfq_slice_idle; |
4427 | cfqd->cfq_group_idle = cfq_group_idle; |
4428 | cfqd->cfq_latency = 1; |
4429 | cfqd->hw_tag = -1; |
4430 | /* |
4431 | * we optimistically start assuming sync ops weren't delayed in last |
4432 | * second, in order to have larger depth for async operations. |
4433 | */ |
4434 | cfqd->last_delayed_sync = jiffies - HZ; |
4435 | return 0; |
4436 | |
4437 | out_free: |
4438 | kfree(cfqd); |
4439 | return ret; |
4440 | } |
4441 | |
4442 | /* |
4443 | * sysfs parts below --> |
4444 | */ |
4445 | static ssize_t |
4446 | cfq_var_show(unsigned int var, char *page) |
4447 | { |
4448 | return sprintf(page, "%d\n", var); |
4449 | } |
4450 | |
4451 | static ssize_t |
4452 | cfq_var_store(unsigned int *var, const char *page, size_t count) |
4453 | { |
4454 | char *p = (char *) page; |
4455 | |
4456 | *var = simple_strtoul(p, &p, 10); |
4457 | return count; |
4458 | } |
4459 | |
4460 | #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ |
4461 | static ssize_t __FUNC(struct elevator_queue *e, char *page) \ |
4462 | { \ |
4463 | struct cfq_data *cfqd = e->elevator_data; \ |
4464 | unsigned int __data = __VAR; \ |
4465 | if (__CONV) \ |
4466 | __data = jiffies_to_msecs(__data); \ |
4467 | return cfq_var_show(__data, (page)); \ |
4468 | } |
4469 | SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); |
4470 | SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1); |
4471 | SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1); |
4472 | SHOW_FUNCTION(cfq_back_seek_max_show, cfqd->cfq_back_max, 0); |
4473 | SHOW_FUNCTION(cfq_back_seek_penalty_show, cfqd->cfq_back_penalty, 0); |
4474 | SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1); |
4475 | SHOW_FUNCTION(cfq_group_idle_show, cfqd->cfq_group_idle, 1); |
4476 | SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1); |
4477 | SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1); |
4478 | SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0); |
4479 | SHOW_FUNCTION(cfq_low_latency_show, cfqd->cfq_latency, 0); |
4480 | SHOW_FUNCTION(cfq_target_latency_show, cfqd->cfq_target_latency, 1); |
4481 | #undef SHOW_FUNCTION |
4482 | |
4483 | #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ |
4484 | static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \ |
4485 | { \ |
4486 | struct cfq_data *cfqd = e->elevator_data; \ |
4487 | unsigned int __data; \ |
4488 | int ret = cfq_var_store(&__data, (page), count); \ |
4489 | if (__data < (MIN)) \ |
4490 | __data = (MIN); \ |
4491 | else if (__data > (MAX)) \ |
4492 | __data = (MAX); \ |
4493 | if (__CONV) \ |
4494 | *(__PTR) = msecs_to_jiffies(__data); \ |
4495 | else \ |
4496 | *(__PTR) = __data; \ |
4497 | return ret; \ |
4498 | } |
4499 | STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); |
4500 | STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, |
4501 | UINT_MAX, 1); |
4502 | STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, |
4503 | UINT_MAX, 1); |
4504 | STORE_FUNCTION(cfq_back_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); |
4505 | STORE_FUNCTION(cfq_back_seek_penalty_store, &cfqd->cfq_back_penalty, 1, |
4506 | UINT_MAX, 0); |
4507 | STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1); |
4508 | STORE_FUNCTION(cfq_group_idle_store, &cfqd->cfq_group_idle, 0, UINT_MAX, 1); |
4509 | STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1); |
4510 | STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1); |
4511 | STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, |
4512 | UINT_MAX, 0); |
4513 | STORE_FUNCTION(cfq_low_latency_store, &cfqd->cfq_latency, 0, 1, 0); |
4514 | STORE_FUNCTION(cfq_target_latency_store, &cfqd->cfq_target_latency, 1, UINT_MAX, 1); |
4515 | #undef STORE_FUNCTION |
4516 | |
4517 | #define CFQ_ATTR(name) \ |
4518 | __ATTR(name, S_IRUGO|S_IWUSR, cfq_##name##_show, cfq_##name##_store) |
4519 | |
4520 | static struct elv_fs_entry cfq_attrs[] = { |
4521 | CFQ_ATTR(quantum), |
4522 | CFQ_ATTR(fifo_expire_sync), |
4523 | CFQ_ATTR(fifo_expire_async), |
4524 | CFQ_ATTR(back_seek_max), |
4525 | CFQ_ATTR(back_seek_penalty), |
4526 | CFQ_ATTR(slice_sync), |
4527 | CFQ_ATTR(slice_async), |
4528 | CFQ_ATTR(slice_async_rq), |
4529 | CFQ_ATTR(slice_idle), |
4530 | CFQ_ATTR(group_idle), |
4531 | CFQ_ATTR(low_latency), |
4532 | CFQ_ATTR(target_latency), |
4533 | __ATTR_NULL |
4534 | }; |
4535 | |
4536 | static struct elevator_type iosched_cfq = { |
4537 | .ops = { |
4538 | .elevator_merge_fn = cfq_merge, |
4539 | .elevator_merged_fn = cfq_merged_request, |
4540 | .elevator_merge_req_fn = cfq_merged_requests, |
4541 | .elevator_allow_merge_fn = cfq_allow_merge, |
4542 | .elevator_bio_merged_fn = cfq_bio_merged, |
4543 | .elevator_dispatch_fn = cfq_dispatch_requests, |
4544 | .elevator_add_req_fn = cfq_insert_request, |
4545 | .elevator_activate_req_fn = cfq_activate_request, |
4546 | .elevator_deactivate_req_fn = cfq_deactivate_request, |
4547 | .elevator_completed_req_fn = cfq_completed_request, |
4548 | .elevator_former_req_fn = elv_rb_former_request, |
4549 | .elevator_latter_req_fn = elv_rb_latter_request, |
4550 | .elevator_init_icq_fn = cfq_init_icq, |
4551 | .elevator_exit_icq_fn = cfq_exit_icq, |
4552 | .elevator_set_req_fn = cfq_set_request, |
4553 | .elevator_put_req_fn = cfq_put_request, |
4554 | .elevator_may_queue_fn = cfq_may_queue, |
4555 | .elevator_init_fn = cfq_init_queue, |
4556 | .elevator_exit_fn = cfq_exit_queue, |
4557 | }, |
4558 | .icq_size = sizeof(struct cfq_io_cq), |
4559 | .icq_align = __alignof__(struct cfq_io_cq), |
4560 | .elevator_attrs = cfq_attrs, |
4561 | .elevator_name = "cfq", |
4562 | .elevator_owner = THIS_MODULE, |
4563 | }; |
4564 | |
4565 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
4566 | static struct blkcg_policy blkcg_policy_cfq = { |
4567 | .pd_size = sizeof(struct cfq_group), |
4568 | .cftypes = cfq_blkcg_files, |
4569 | |
4570 | .pd_init_fn = cfq_pd_init, |
4571 | .pd_offline_fn = cfq_pd_offline, |
4572 | .pd_reset_stats_fn = cfq_pd_reset_stats, |
4573 | }; |
4574 | #endif |
4575 | |
4576 | static int __init cfq_init(void) |
4577 | { |
4578 | int ret; |
4579 | |
4580 | /* |
4581 | * could be 0 on HZ < 1000 setups |
4582 | */ |
4583 | if (!cfq_slice_async) |
4584 | cfq_slice_async = 1; |
4585 | if (!cfq_slice_idle) |
4586 | cfq_slice_idle = 1; |
4587 | |
4588 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
4589 | if (!cfq_group_idle) |
4590 | cfq_group_idle = 1; |
4591 | |
4592 | ret = blkcg_policy_register(&blkcg_policy_cfq); |
4593 | if (ret) |
4594 | return ret; |
4595 | #else |
4596 | cfq_group_idle = 0; |
4597 | #endif |
4598 | |
4599 | ret = -ENOMEM; |
4600 | cfq_pool = KMEM_CACHE(cfq_queue, 0); |
4601 | if (!cfq_pool) |
4602 | goto err_pol_unreg; |
4603 | |
4604 | ret = elv_register(&iosched_cfq); |
4605 | if (ret) |
4606 | goto err_free_pool; |
4607 | |
4608 | return 0; |
4609 | |
4610 | err_free_pool: |
4611 | kmem_cache_destroy(cfq_pool); |
4612 | err_pol_unreg: |
4613 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
4614 | blkcg_policy_unregister(&blkcg_policy_cfq); |
4615 | #endif |
4616 | return ret; |
4617 | } |
4618 | |
4619 | static void __exit cfq_exit(void) |
4620 | { |
4621 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
4622 | blkcg_policy_unregister(&blkcg_policy_cfq); |
4623 | #endif |
4624 | elv_unregister(&iosched_cfq); |
4625 | kmem_cache_destroy(cfq_pool); |
4626 | } |
4627 | |
4628 | module_init(cfq_init); |
4629 | module_exit(cfq_exit); |
4630 | |
4631 | MODULE_AUTHOR("Jens Axboe"); |
4632 | MODULE_LICENSE("GPL"); |
4633 | MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler"); |
4634 |
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