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Source at commit 2604e7f9a98c27be50a0c3ff7503b6a5ea8f6cfe created 12 years 7 months ago. By Maarten ter Huurne, cpufreq_stats: Support runtime changes to frequency table | |
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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 | unsigned total_weight; |
89 | u64 min_vdisktime; |
90 | struct cfq_ttime ttime; |
91 | }; |
92 | #define CFQ_RB_ROOT (struct cfq_rb_root) { .rb = RB_ROOT, \ |
93 | .ttime = {.last_end_request = jiffies,},} |
94 | |
95 | /* |
96 | * Per process-grouping structure |
97 | */ |
98 | struct cfq_queue { |
99 | /* reference count */ |
100 | int ref; |
101 | /* various state flags, see below */ |
102 | unsigned int flags; |
103 | /* parent cfq_data */ |
104 | struct cfq_data *cfqd; |
105 | /* service_tree member */ |
106 | struct rb_node rb_node; |
107 | /* service_tree key */ |
108 | unsigned long rb_key; |
109 | /* prio tree member */ |
110 | struct rb_node p_node; |
111 | /* prio tree root we belong to, if any */ |
112 | struct rb_root *p_root; |
113 | /* sorted list of pending requests */ |
114 | struct rb_root sort_list; |
115 | /* if fifo isn't expired, next request to serve */ |
116 | struct request *next_rq; |
117 | /* requests queued in sort_list */ |
118 | int queued[2]; |
119 | /* currently allocated requests */ |
120 | int allocated[2]; |
121 | /* fifo list of requests in sort_list */ |
122 | struct list_head fifo; |
123 | |
124 | /* time when queue got scheduled in to dispatch first request. */ |
125 | unsigned long dispatch_start; |
126 | unsigned int allocated_slice; |
127 | unsigned int slice_dispatch; |
128 | /* time when first request from queue completed and slice started. */ |
129 | unsigned long slice_start; |
130 | unsigned long slice_end; |
131 | long slice_resid; |
132 | |
133 | /* pending priority requests */ |
134 | int prio_pending; |
135 | /* number of requests that are on the dispatch list or inside driver */ |
136 | int dispatched; |
137 | |
138 | /* io prio of this group */ |
139 | unsigned short ioprio, org_ioprio; |
140 | unsigned short ioprio_class; |
141 | |
142 | pid_t pid; |
143 | |
144 | u32 seek_history; |
145 | sector_t last_request_pos; |
146 | |
147 | struct cfq_rb_root *service_tree; |
148 | struct cfq_queue *new_cfqq; |
149 | struct cfq_group *cfqg; |
150 | /* Number of sectors dispatched from queue in single dispatch round */ |
151 | unsigned long nr_sectors; |
152 | }; |
153 | |
154 | /* |
155 | * First index in the service_trees. |
156 | * IDLE is handled separately, so it has negative index |
157 | */ |
158 | enum wl_prio_t { |
159 | BE_WORKLOAD = 0, |
160 | RT_WORKLOAD = 1, |
161 | IDLE_WORKLOAD = 2, |
162 | CFQ_PRIO_NR, |
163 | }; |
164 | |
165 | /* |
166 | * Second index in the service_trees. |
167 | */ |
168 | enum wl_type_t { |
169 | ASYNC_WORKLOAD = 0, |
170 | SYNC_NOIDLE_WORKLOAD = 1, |
171 | SYNC_WORKLOAD = 2 |
172 | }; |
173 | |
174 | struct cfqg_stats { |
175 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
176 | /* total bytes transferred */ |
177 | struct blkg_rwstat service_bytes; |
178 | /* total IOs serviced, post merge */ |
179 | struct blkg_rwstat serviced; |
180 | /* number of ios merged */ |
181 | struct blkg_rwstat merged; |
182 | /* total time spent on device in ns, may not be accurate w/ queueing */ |
183 | struct blkg_rwstat service_time; |
184 | /* total time spent waiting in scheduler queue in ns */ |
185 | struct blkg_rwstat wait_time; |
186 | /* number of IOs queued up */ |
187 | struct blkg_rwstat queued; |
188 | /* total sectors transferred */ |
189 | struct blkg_stat sectors; |
190 | /* total disk time and nr sectors dispatched by this group */ |
191 | struct blkg_stat time; |
192 | #ifdef CONFIG_DEBUG_BLK_CGROUP |
193 | /* time not charged to this cgroup */ |
194 | struct blkg_stat unaccounted_time; |
195 | /* sum of number of ios queued across all samples */ |
196 | struct blkg_stat avg_queue_size_sum; |
197 | /* count of samples taken for average */ |
198 | struct blkg_stat avg_queue_size_samples; |
199 | /* how many times this group has been removed from service tree */ |
200 | struct blkg_stat dequeue; |
201 | /* total time spent waiting for it to be assigned a timeslice. */ |
202 | struct blkg_stat group_wait_time; |
203 | /* time spent idling for this blkcg_gq */ |
204 | struct blkg_stat idle_time; |
205 | /* total time with empty current active q with other requests queued */ |
206 | struct blkg_stat empty_time; |
207 | /* fields after this shouldn't be cleared on stat reset */ |
208 | uint64_t start_group_wait_time; |
209 | uint64_t start_idle_time; |
210 | uint64_t start_empty_time; |
211 | uint16_t flags; |
212 | #endif /* CONFIG_DEBUG_BLK_CGROUP */ |
213 | #endif /* CONFIG_CFQ_GROUP_IOSCHED */ |
214 | }; |
215 | |
216 | /* This is per cgroup per device grouping structure */ |
217 | struct cfq_group { |
218 | /* must be the first member */ |
219 | struct blkg_policy_data pd; |
220 | |
221 | /* group service_tree member */ |
222 | struct rb_node rb_node; |
223 | |
224 | /* group service_tree key */ |
225 | u64 vdisktime; |
226 | unsigned int weight; |
227 | unsigned int new_weight; |
228 | unsigned int dev_weight; |
229 | |
230 | /* number of cfqq currently on this group */ |
231 | int nr_cfqq; |
232 | |
233 | /* |
234 | * Per group busy queues average. Useful for workload slice calc. We |
235 | * create the array for each prio class but at run time it is used |
236 | * only for RT and BE class and slot for IDLE class remains unused. |
237 | * This is primarily done to avoid confusion and a gcc warning. |
238 | */ |
239 | unsigned int busy_queues_avg[CFQ_PRIO_NR]; |
240 | /* |
241 | * rr lists of queues with requests. We maintain service trees for |
242 | * RT and BE classes. These trees are subdivided in subclasses |
243 | * of SYNC, SYNC_NOIDLE and ASYNC based on workload type. For IDLE |
244 | * class there is no subclassification and all the cfq queues go on |
245 | * a single tree service_tree_idle. |
246 | * Counts are embedded in the cfq_rb_root |
247 | */ |
248 | struct cfq_rb_root service_trees[2][3]; |
249 | struct cfq_rb_root service_tree_idle; |
250 | |
251 | unsigned long saved_workload_slice; |
252 | enum wl_type_t saved_workload; |
253 | enum wl_prio_t saved_serving_prio; |
254 | |
255 | /* number of requests that are on the dispatch list or inside driver */ |
256 | int dispatched; |
257 | struct cfq_ttime ttime; |
258 | struct cfqg_stats stats; |
259 | }; |
260 | |
261 | struct cfq_io_cq { |
262 | struct io_cq icq; /* must be the first member */ |
263 | struct cfq_queue *cfqq[2]; |
264 | struct cfq_ttime ttime; |
265 | int ioprio; /* the current ioprio */ |
266 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
267 | uint64_t blkcg_id; /* the current blkcg ID */ |
268 | #endif |
269 | }; |
270 | |
271 | /* |
272 | * Per block device queue structure |
273 | */ |
274 | struct cfq_data { |
275 | struct request_queue *queue; |
276 | /* Root service tree for cfq_groups */ |
277 | struct cfq_rb_root grp_service_tree; |
278 | struct cfq_group *root_group; |
279 | |
280 | /* |
281 | * The priority currently being served |
282 | */ |
283 | enum wl_prio_t serving_prio; |
284 | enum wl_type_t serving_type; |
285 | unsigned long workload_expires; |
286 | struct cfq_group *serving_group; |
287 | |
288 | /* |
289 | * Each priority tree is sorted by next_request position. These |
290 | * trees are used when determining if two or more queues are |
291 | * interleaving requests (see cfq_close_cooperator). |
292 | */ |
293 | struct rb_root prio_trees[CFQ_PRIO_LISTS]; |
294 | |
295 | unsigned int busy_queues; |
296 | unsigned int busy_sync_queues; |
297 | |
298 | int rq_in_driver; |
299 | int rq_in_flight[2]; |
300 | |
301 | /* |
302 | * queue-depth detection |
303 | */ |
304 | int rq_queued; |
305 | int hw_tag; |
306 | /* |
307 | * hw_tag can be |
308 | * -1 => indeterminate, (cfq will behave as if NCQ is present, to allow better detection) |
309 | * 1 => NCQ is present (hw_tag_est_depth is the estimated max depth) |
310 | * 0 => no NCQ |
311 | */ |
312 | int hw_tag_est_depth; |
313 | unsigned int hw_tag_samples; |
314 | |
315 | /* |
316 | * idle window management |
317 | */ |
318 | struct timer_list idle_slice_timer; |
319 | struct work_struct unplug_work; |
320 | |
321 | struct cfq_queue *active_queue; |
322 | struct cfq_io_cq *active_cic; |
323 | |
324 | /* |
325 | * async queue for each priority case |
326 | */ |
327 | struct cfq_queue *async_cfqq[2][IOPRIO_BE_NR]; |
328 | struct cfq_queue *async_idle_cfqq; |
329 | |
330 | sector_t last_position; |
331 | |
332 | /* |
333 | * tunables, see top of file |
334 | */ |
335 | unsigned int cfq_quantum; |
336 | unsigned int cfq_fifo_expire[2]; |
337 | unsigned int cfq_back_penalty; |
338 | unsigned int cfq_back_max; |
339 | unsigned int cfq_slice[2]; |
340 | unsigned int cfq_slice_async_rq; |
341 | unsigned int cfq_slice_idle; |
342 | unsigned int cfq_group_idle; |
343 | unsigned int cfq_latency; |
344 | unsigned int cfq_target_latency; |
345 | |
346 | /* |
347 | * Fallback dummy cfqq for extreme OOM conditions |
348 | */ |
349 | struct cfq_queue oom_cfqq; |
350 | |
351 | unsigned long last_delayed_sync; |
352 | }; |
353 | |
354 | static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd); |
355 | |
356 | static struct cfq_rb_root *service_tree_for(struct cfq_group *cfqg, |
357 | enum wl_prio_t prio, |
358 | enum wl_type_t type) |
359 | { |
360 | if (!cfqg) |
361 | return NULL; |
362 | |
363 | if (prio == IDLE_WORKLOAD) |
364 | return &cfqg->service_tree_idle; |
365 | |
366 | return &cfqg->service_trees[prio][type]; |
367 | } |
368 | |
369 | enum cfqq_state_flags { |
370 | CFQ_CFQQ_FLAG_on_rr = 0, /* on round-robin busy list */ |
371 | CFQ_CFQQ_FLAG_wait_request, /* waiting for a request */ |
372 | CFQ_CFQQ_FLAG_must_dispatch, /* must be allowed a dispatch */ |
373 | CFQ_CFQQ_FLAG_must_alloc_slice, /* per-slice must_alloc flag */ |
374 | CFQ_CFQQ_FLAG_fifo_expire, /* FIFO checked in this slice */ |
375 | CFQ_CFQQ_FLAG_idle_window, /* slice idling enabled */ |
376 | CFQ_CFQQ_FLAG_prio_changed, /* task priority has changed */ |
377 | CFQ_CFQQ_FLAG_slice_new, /* no requests dispatched in slice */ |
378 | CFQ_CFQQ_FLAG_sync, /* synchronous queue */ |
379 | CFQ_CFQQ_FLAG_coop, /* cfqq is shared */ |
380 | CFQ_CFQQ_FLAG_split_coop, /* shared cfqq will be splitted */ |
381 | CFQ_CFQQ_FLAG_deep, /* sync cfqq experienced large depth */ |
382 | CFQ_CFQQ_FLAG_wait_busy, /* Waiting for next request */ |
383 | }; |
384 | |
385 | #define CFQ_CFQQ_FNS(name) \ |
386 | static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \ |
387 | { \ |
388 | (cfqq)->flags |= (1 << CFQ_CFQQ_FLAG_##name); \ |
389 | } \ |
390 | static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \ |
391 | { \ |
392 | (cfqq)->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \ |
393 | } \ |
394 | static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \ |
395 | { \ |
396 | return ((cfqq)->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \ |
397 | } |
398 | |
399 | CFQ_CFQQ_FNS(on_rr); |
400 | CFQ_CFQQ_FNS(wait_request); |
401 | CFQ_CFQQ_FNS(must_dispatch); |
402 | CFQ_CFQQ_FNS(must_alloc_slice); |
403 | CFQ_CFQQ_FNS(fifo_expire); |
404 | CFQ_CFQQ_FNS(idle_window); |
405 | CFQ_CFQQ_FNS(prio_changed); |
406 | CFQ_CFQQ_FNS(slice_new); |
407 | CFQ_CFQQ_FNS(sync); |
408 | CFQ_CFQQ_FNS(coop); |
409 | CFQ_CFQQ_FNS(split_coop); |
410 | CFQ_CFQQ_FNS(deep); |
411 | CFQ_CFQQ_FNS(wait_busy); |
412 | #undef CFQ_CFQQ_FNS |
413 | |
414 | static inline struct cfq_group *pd_to_cfqg(struct blkg_policy_data *pd) |
415 | { |
416 | return pd ? container_of(pd, struct cfq_group, pd) : NULL; |
417 | } |
418 | |
419 | static inline struct blkcg_gq *cfqg_to_blkg(struct cfq_group *cfqg) |
420 | { |
421 | return pd_to_blkg(&cfqg->pd); |
422 | } |
423 | |
424 | #if defined(CONFIG_CFQ_GROUP_IOSCHED) && defined(CONFIG_DEBUG_BLK_CGROUP) |
425 | |
426 | /* cfqg stats flags */ |
427 | enum cfqg_stats_flags { |
428 | CFQG_stats_waiting = 0, |
429 | CFQG_stats_idling, |
430 | CFQG_stats_empty, |
431 | }; |
432 | |
433 | #define CFQG_FLAG_FNS(name) \ |
434 | static inline void cfqg_stats_mark_##name(struct cfqg_stats *stats) \ |
435 | { \ |
436 | stats->flags |= (1 << CFQG_stats_##name); \ |
437 | } \ |
438 | static inline void cfqg_stats_clear_##name(struct cfqg_stats *stats) \ |
439 | { \ |
440 | stats->flags &= ~(1 << CFQG_stats_##name); \ |
441 | } \ |
442 | static inline int cfqg_stats_##name(struct cfqg_stats *stats) \ |
443 | { \ |
444 | return (stats->flags & (1 << CFQG_stats_##name)) != 0; \ |
445 | } \ |
446 | |
447 | CFQG_FLAG_FNS(waiting) |
448 | CFQG_FLAG_FNS(idling) |
449 | CFQG_FLAG_FNS(empty) |
450 | #undef CFQG_FLAG_FNS |
451 | |
452 | /* This should be called with the queue_lock held. */ |
453 | static void cfqg_stats_update_group_wait_time(struct cfqg_stats *stats) |
454 | { |
455 | unsigned long long now; |
456 | |
457 | if (!cfqg_stats_waiting(stats)) |
458 | return; |
459 | |
460 | now = sched_clock(); |
461 | if (time_after64(now, stats->start_group_wait_time)) |
462 | blkg_stat_add(&stats->group_wait_time, |
463 | now - stats->start_group_wait_time); |
464 | cfqg_stats_clear_waiting(stats); |
465 | } |
466 | |
467 | /* This should be called with the queue_lock held. */ |
468 | static void cfqg_stats_set_start_group_wait_time(struct cfq_group *cfqg, |
469 | struct cfq_group *curr_cfqg) |
470 | { |
471 | struct cfqg_stats *stats = &cfqg->stats; |
472 | |
473 | if (cfqg_stats_waiting(stats)) |
474 | return; |
475 | if (cfqg == curr_cfqg) |
476 | return; |
477 | stats->start_group_wait_time = sched_clock(); |
478 | cfqg_stats_mark_waiting(stats); |
479 | } |
480 | |
481 | /* This should be called with the queue_lock held. */ |
482 | static void cfqg_stats_end_empty_time(struct cfqg_stats *stats) |
483 | { |
484 | unsigned long long now; |
485 | |
486 | if (!cfqg_stats_empty(stats)) |
487 | return; |
488 | |
489 | now = sched_clock(); |
490 | if (time_after64(now, stats->start_empty_time)) |
491 | blkg_stat_add(&stats->empty_time, |
492 | now - stats->start_empty_time); |
493 | cfqg_stats_clear_empty(stats); |
494 | } |
495 | |
496 | static void cfqg_stats_update_dequeue(struct cfq_group *cfqg) |
497 | { |
498 | blkg_stat_add(&cfqg->stats.dequeue, 1); |
499 | } |
500 | |
501 | static void cfqg_stats_set_start_empty_time(struct cfq_group *cfqg) |
502 | { |
503 | struct cfqg_stats *stats = &cfqg->stats; |
504 | |
505 | if (blkg_rwstat_sum(&stats->queued)) |
506 | return; |
507 | |
508 | /* |
509 | * group is already marked empty. This can happen if cfqq got new |
510 | * request in parent group and moved to this group while being added |
511 | * to service tree. Just ignore the event and move on. |
512 | */ |
513 | if (cfqg_stats_empty(stats)) |
514 | return; |
515 | |
516 | stats->start_empty_time = sched_clock(); |
517 | cfqg_stats_mark_empty(stats); |
518 | } |
519 | |
520 | static void cfqg_stats_update_idle_time(struct cfq_group *cfqg) |
521 | { |
522 | struct cfqg_stats *stats = &cfqg->stats; |
523 | |
524 | if (cfqg_stats_idling(stats)) { |
525 | unsigned long long now = sched_clock(); |
526 | |
527 | if (time_after64(now, stats->start_idle_time)) |
528 | blkg_stat_add(&stats->idle_time, |
529 | now - stats->start_idle_time); |
530 | cfqg_stats_clear_idling(stats); |
531 | } |
532 | } |
533 | |
534 | static void cfqg_stats_set_start_idle_time(struct cfq_group *cfqg) |
535 | { |
536 | struct cfqg_stats *stats = &cfqg->stats; |
537 | |
538 | BUG_ON(cfqg_stats_idling(stats)); |
539 | |
540 | stats->start_idle_time = sched_clock(); |
541 | cfqg_stats_mark_idling(stats); |
542 | } |
543 | |
544 | static void cfqg_stats_update_avg_queue_size(struct cfq_group *cfqg) |
545 | { |
546 | struct cfqg_stats *stats = &cfqg->stats; |
547 | |
548 | blkg_stat_add(&stats->avg_queue_size_sum, |
549 | blkg_rwstat_sum(&stats->queued)); |
550 | blkg_stat_add(&stats->avg_queue_size_samples, 1); |
551 | cfqg_stats_update_group_wait_time(stats); |
552 | } |
553 | |
554 | #else /* CONFIG_CFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */ |
555 | |
556 | static inline void cfqg_stats_set_start_group_wait_time(struct cfq_group *cfqg, struct cfq_group *curr_cfqg) { } |
557 | static inline void cfqg_stats_end_empty_time(struct cfqg_stats *stats) { } |
558 | static inline void cfqg_stats_update_dequeue(struct cfq_group *cfqg) { } |
559 | static inline void cfqg_stats_set_start_empty_time(struct cfq_group *cfqg) { } |
560 | static inline void cfqg_stats_update_idle_time(struct cfq_group *cfqg) { } |
561 | static inline void cfqg_stats_set_start_idle_time(struct cfq_group *cfqg) { } |
562 | static inline void cfqg_stats_update_avg_queue_size(struct cfq_group *cfqg) { } |
563 | |
564 | #endif /* CONFIG_CFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */ |
565 | |
566 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
567 | |
568 | static struct blkcg_policy blkcg_policy_cfq; |
569 | |
570 | static inline struct cfq_group *blkg_to_cfqg(struct blkcg_gq *blkg) |
571 | { |
572 | return pd_to_cfqg(blkg_to_pd(blkg, &blkcg_policy_cfq)); |
573 | } |
574 | |
575 | static inline void cfqg_get(struct cfq_group *cfqg) |
576 | { |
577 | return blkg_get(cfqg_to_blkg(cfqg)); |
578 | } |
579 | |
580 | static inline void cfqg_put(struct cfq_group *cfqg) |
581 | { |
582 | return blkg_put(cfqg_to_blkg(cfqg)); |
583 | } |
584 | |
585 | #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) do { \ |
586 | char __pbuf[128]; \ |
587 | \ |
588 | blkg_path(cfqg_to_blkg((cfqq)->cfqg), __pbuf, sizeof(__pbuf)); \ |
589 | blk_add_trace_msg((cfqd)->queue, "cfq%d%c %s " fmt, (cfqq)->pid, \ |
590 | cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \ |
591 | __pbuf, ##args); \ |
592 | } while (0) |
593 | |
594 | #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) do { \ |
595 | char __pbuf[128]; \ |
596 | \ |
597 | blkg_path(cfqg_to_blkg(cfqg), __pbuf, sizeof(__pbuf)); \ |
598 | blk_add_trace_msg((cfqd)->queue, "%s " fmt, __pbuf, ##args); \ |
599 | } while (0) |
600 | |
601 | static inline void cfqg_stats_update_io_add(struct cfq_group *cfqg, |
602 | struct cfq_group *curr_cfqg, int rw) |
603 | { |
604 | blkg_rwstat_add(&cfqg->stats.queued, rw, 1); |
605 | cfqg_stats_end_empty_time(&cfqg->stats); |
606 | cfqg_stats_set_start_group_wait_time(cfqg, curr_cfqg); |
607 | } |
608 | |
609 | static inline void cfqg_stats_update_timeslice_used(struct cfq_group *cfqg, |
610 | unsigned long time, unsigned long unaccounted_time) |
611 | { |
612 | blkg_stat_add(&cfqg->stats.time, time); |
613 | #ifdef CONFIG_DEBUG_BLK_CGROUP |
614 | blkg_stat_add(&cfqg->stats.unaccounted_time, unaccounted_time); |
615 | #endif |
616 | } |
617 | |
618 | static inline void cfqg_stats_update_io_remove(struct cfq_group *cfqg, int rw) |
619 | { |
620 | blkg_rwstat_add(&cfqg->stats.queued, rw, -1); |
621 | } |
622 | |
623 | static inline void cfqg_stats_update_io_merged(struct cfq_group *cfqg, int rw) |
624 | { |
625 | blkg_rwstat_add(&cfqg->stats.merged, rw, 1); |
626 | } |
627 | |
628 | static inline void cfqg_stats_update_dispatch(struct cfq_group *cfqg, |
629 | uint64_t bytes, int rw) |
630 | { |
631 | blkg_stat_add(&cfqg->stats.sectors, bytes >> 9); |
632 | blkg_rwstat_add(&cfqg->stats.serviced, rw, 1); |
633 | blkg_rwstat_add(&cfqg->stats.service_bytes, rw, bytes); |
634 | } |
635 | |
636 | static inline void cfqg_stats_update_completion(struct cfq_group *cfqg, |
637 | uint64_t start_time, uint64_t io_start_time, int rw) |
638 | { |
639 | struct cfqg_stats *stats = &cfqg->stats; |
640 | unsigned long long now = sched_clock(); |
641 | |
642 | if (time_after64(now, io_start_time)) |
643 | blkg_rwstat_add(&stats->service_time, rw, now - io_start_time); |
644 | if (time_after64(io_start_time, start_time)) |
645 | blkg_rwstat_add(&stats->wait_time, rw, |
646 | io_start_time - start_time); |
647 | } |
648 | |
649 | static void cfq_pd_reset_stats(struct blkcg_gq *blkg) |
650 | { |
651 | struct cfq_group *cfqg = blkg_to_cfqg(blkg); |
652 | struct cfqg_stats *stats = &cfqg->stats; |
653 | |
654 | /* queued stats shouldn't be cleared */ |
655 | blkg_rwstat_reset(&stats->service_bytes); |
656 | blkg_rwstat_reset(&stats->serviced); |
657 | blkg_rwstat_reset(&stats->merged); |
658 | blkg_rwstat_reset(&stats->service_time); |
659 | blkg_rwstat_reset(&stats->wait_time); |
660 | blkg_stat_reset(&stats->time); |
661 | #ifdef CONFIG_DEBUG_BLK_CGROUP |
662 | blkg_stat_reset(&stats->unaccounted_time); |
663 | blkg_stat_reset(&stats->avg_queue_size_sum); |
664 | blkg_stat_reset(&stats->avg_queue_size_samples); |
665 | blkg_stat_reset(&stats->dequeue); |
666 | blkg_stat_reset(&stats->group_wait_time); |
667 | blkg_stat_reset(&stats->idle_time); |
668 | blkg_stat_reset(&stats->empty_time); |
669 | #endif |
670 | } |
671 | |
672 | #else /* CONFIG_CFQ_GROUP_IOSCHED */ |
673 | |
674 | static inline void cfqg_get(struct cfq_group *cfqg) { } |
675 | static inline void cfqg_put(struct cfq_group *cfqg) { } |
676 | |
677 | #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \ |
678 | blk_add_trace_msg((cfqd)->queue, "cfq%d " fmt, (cfqq)->pid, ##args) |
679 | #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) do {} while (0) |
680 | |
681 | static inline void cfqg_stats_update_io_add(struct cfq_group *cfqg, |
682 | struct cfq_group *curr_cfqg, int rw) { } |
683 | static inline void cfqg_stats_update_timeslice_used(struct cfq_group *cfqg, |
684 | unsigned long time, unsigned long unaccounted_time) { } |
685 | static inline void cfqg_stats_update_io_remove(struct cfq_group *cfqg, int rw) { } |
686 | static inline void cfqg_stats_update_io_merged(struct cfq_group *cfqg, int rw) { } |
687 | static inline void cfqg_stats_update_dispatch(struct cfq_group *cfqg, |
688 | uint64_t bytes, int rw) { } |
689 | static inline void cfqg_stats_update_completion(struct cfq_group *cfqg, |
690 | uint64_t start_time, uint64_t io_start_time, int rw) { } |
691 | |
692 | #endif /* CONFIG_CFQ_GROUP_IOSCHED */ |
693 | |
694 | #define cfq_log(cfqd, fmt, args...) \ |
695 | blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args) |
696 | |
697 | /* Traverses through cfq group service trees */ |
698 | #define for_each_cfqg_st(cfqg, i, j, st) \ |
699 | for (i = 0; i <= IDLE_WORKLOAD; i++) \ |
700 | for (j = 0, st = i < IDLE_WORKLOAD ? &cfqg->service_trees[i][j]\ |
701 | : &cfqg->service_tree_idle; \ |
702 | (i < IDLE_WORKLOAD && j <= SYNC_WORKLOAD) || \ |
703 | (i == IDLE_WORKLOAD && j == 0); \ |
704 | j++, st = i < IDLE_WORKLOAD ? \ |
705 | &cfqg->service_trees[i][j]: NULL) \ |
706 | |
707 | static inline bool cfq_io_thinktime_big(struct cfq_data *cfqd, |
708 | struct cfq_ttime *ttime, bool group_idle) |
709 | { |
710 | unsigned long slice; |
711 | if (!sample_valid(ttime->ttime_samples)) |
712 | return false; |
713 | if (group_idle) |
714 | slice = cfqd->cfq_group_idle; |
715 | else |
716 | slice = cfqd->cfq_slice_idle; |
717 | return ttime->ttime_mean > slice; |
718 | } |
719 | |
720 | static inline bool iops_mode(struct cfq_data *cfqd) |
721 | { |
722 | /* |
723 | * If we are not idling on queues and it is a NCQ drive, parallel |
724 | * execution of requests is on and measuring time is not possible |
725 | * in most of the cases until and unless we drive shallower queue |
726 | * depths and that becomes a performance bottleneck. In such cases |
727 | * switch to start providing fairness in terms of number of IOs. |
728 | */ |
729 | if (!cfqd->cfq_slice_idle && cfqd->hw_tag) |
730 | return true; |
731 | else |
732 | return false; |
733 | } |
734 | |
735 | static inline enum wl_prio_t cfqq_prio(struct cfq_queue *cfqq) |
736 | { |
737 | if (cfq_class_idle(cfqq)) |
738 | return IDLE_WORKLOAD; |
739 | if (cfq_class_rt(cfqq)) |
740 | return RT_WORKLOAD; |
741 | return BE_WORKLOAD; |
742 | } |
743 | |
744 | |
745 | static enum wl_type_t cfqq_type(struct cfq_queue *cfqq) |
746 | { |
747 | if (!cfq_cfqq_sync(cfqq)) |
748 | return ASYNC_WORKLOAD; |
749 | if (!cfq_cfqq_idle_window(cfqq)) |
750 | return SYNC_NOIDLE_WORKLOAD; |
751 | return SYNC_WORKLOAD; |
752 | } |
753 | |
754 | static inline int cfq_group_busy_queues_wl(enum wl_prio_t wl, |
755 | struct cfq_data *cfqd, |
756 | struct cfq_group *cfqg) |
757 | { |
758 | if (wl == IDLE_WORKLOAD) |
759 | return cfqg->service_tree_idle.count; |
760 | |
761 | return cfqg->service_trees[wl][ASYNC_WORKLOAD].count |
762 | + cfqg->service_trees[wl][SYNC_NOIDLE_WORKLOAD].count |
763 | + cfqg->service_trees[wl][SYNC_WORKLOAD].count; |
764 | } |
765 | |
766 | static inline int cfqg_busy_async_queues(struct cfq_data *cfqd, |
767 | struct cfq_group *cfqg) |
768 | { |
769 | return cfqg->service_trees[RT_WORKLOAD][ASYNC_WORKLOAD].count |
770 | + cfqg->service_trees[BE_WORKLOAD][ASYNC_WORKLOAD].count; |
771 | } |
772 | |
773 | static void cfq_dispatch_insert(struct request_queue *, struct request *); |
774 | static struct cfq_queue *cfq_get_queue(struct cfq_data *cfqd, bool is_sync, |
775 | struct cfq_io_cq *cic, struct bio *bio, |
776 | gfp_t gfp_mask); |
777 | |
778 | static inline struct cfq_io_cq *icq_to_cic(struct io_cq *icq) |
779 | { |
780 | /* cic->icq is the first member, %NULL will convert to %NULL */ |
781 | return container_of(icq, struct cfq_io_cq, icq); |
782 | } |
783 | |
784 | static inline struct cfq_io_cq *cfq_cic_lookup(struct cfq_data *cfqd, |
785 | struct io_context *ioc) |
786 | { |
787 | if (ioc) |
788 | return icq_to_cic(ioc_lookup_icq(ioc, cfqd->queue)); |
789 | return NULL; |
790 | } |
791 | |
792 | static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_cq *cic, bool is_sync) |
793 | { |
794 | return cic->cfqq[is_sync]; |
795 | } |
796 | |
797 | static inline void cic_set_cfqq(struct cfq_io_cq *cic, struct cfq_queue *cfqq, |
798 | bool is_sync) |
799 | { |
800 | cic->cfqq[is_sync] = cfqq; |
801 | } |
802 | |
803 | static inline struct cfq_data *cic_to_cfqd(struct cfq_io_cq *cic) |
804 | { |
805 | return cic->icq.q->elevator->elevator_data; |
806 | } |
807 | |
808 | /* |
809 | * We regard a request as SYNC, if it's either a read or has the SYNC bit |
810 | * set (in which case it could also be direct WRITE). |
811 | */ |
812 | static inline bool cfq_bio_sync(struct bio *bio) |
813 | { |
814 | return bio_data_dir(bio) == READ || (bio->bi_rw & REQ_SYNC); |
815 | } |
816 | |
817 | /* |
818 | * scheduler run of queue, if there are requests pending and no one in the |
819 | * driver that will restart queueing |
820 | */ |
821 | static inline void cfq_schedule_dispatch(struct cfq_data *cfqd) |
822 | { |
823 | if (cfqd->busy_queues) { |
824 | cfq_log(cfqd, "schedule dispatch"); |
825 | kblockd_schedule_work(cfqd->queue, &cfqd->unplug_work); |
826 | } |
827 | } |
828 | |
829 | /* |
830 | * Scale schedule slice based on io priority. Use the sync time slice only |
831 | * if a queue is marked sync and has sync io queued. A sync queue with async |
832 | * io only, should not get full sync slice length. |
833 | */ |
834 | static inline int cfq_prio_slice(struct cfq_data *cfqd, bool sync, |
835 | unsigned short prio) |
836 | { |
837 | const int base_slice = cfqd->cfq_slice[sync]; |
838 | |
839 | WARN_ON(prio >= IOPRIO_BE_NR); |
840 | |
841 | return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - prio)); |
842 | } |
843 | |
844 | static inline int |
845 | cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
846 | { |
847 | return cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio); |
848 | } |
849 | |
850 | static inline u64 cfq_scale_slice(unsigned long delta, struct cfq_group *cfqg) |
851 | { |
852 | u64 d = delta << CFQ_SERVICE_SHIFT; |
853 | |
854 | d = d * CFQ_WEIGHT_DEFAULT; |
855 | do_div(d, cfqg->weight); |
856 | return d; |
857 | } |
858 | |
859 | static inline u64 max_vdisktime(u64 min_vdisktime, u64 vdisktime) |
860 | { |
861 | s64 delta = (s64)(vdisktime - min_vdisktime); |
862 | if (delta > 0) |
863 | min_vdisktime = vdisktime; |
864 | |
865 | return min_vdisktime; |
866 | } |
867 | |
868 | static inline u64 min_vdisktime(u64 min_vdisktime, u64 vdisktime) |
869 | { |
870 | s64 delta = (s64)(vdisktime - min_vdisktime); |
871 | if (delta < 0) |
872 | min_vdisktime = vdisktime; |
873 | |
874 | return min_vdisktime; |
875 | } |
876 | |
877 | static void update_min_vdisktime(struct cfq_rb_root *st) |
878 | { |
879 | struct cfq_group *cfqg; |
880 | |
881 | if (st->left) { |
882 | cfqg = rb_entry_cfqg(st->left); |
883 | st->min_vdisktime = max_vdisktime(st->min_vdisktime, |
884 | cfqg->vdisktime); |
885 | } |
886 | } |
887 | |
888 | /* |
889 | * get averaged number of queues of RT/BE priority. |
890 | * average is updated, with a formula that gives more weight to higher numbers, |
891 | * to quickly follows sudden increases and decrease slowly |
892 | */ |
893 | |
894 | static inline unsigned cfq_group_get_avg_queues(struct cfq_data *cfqd, |
895 | struct cfq_group *cfqg, bool rt) |
896 | { |
897 | unsigned min_q, max_q; |
898 | unsigned mult = cfq_hist_divisor - 1; |
899 | unsigned round = cfq_hist_divisor / 2; |
900 | unsigned busy = cfq_group_busy_queues_wl(rt, cfqd, cfqg); |
901 | |
902 | min_q = min(cfqg->busy_queues_avg[rt], busy); |
903 | max_q = max(cfqg->busy_queues_avg[rt], busy); |
904 | cfqg->busy_queues_avg[rt] = (mult * max_q + min_q + round) / |
905 | cfq_hist_divisor; |
906 | return cfqg->busy_queues_avg[rt]; |
907 | } |
908 | |
909 | static inline unsigned |
910 | cfq_group_slice(struct cfq_data *cfqd, struct cfq_group *cfqg) |
911 | { |
912 | struct cfq_rb_root *st = &cfqd->grp_service_tree; |
913 | |
914 | return cfqd->cfq_target_latency * cfqg->weight / st->total_weight; |
915 | } |
916 | |
917 | static inline unsigned |
918 | cfq_scaled_cfqq_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
919 | { |
920 | unsigned slice = cfq_prio_to_slice(cfqd, cfqq); |
921 | if (cfqd->cfq_latency) { |
922 | /* |
923 | * interested queues (we consider only the ones with the same |
924 | * priority class in the cfq group) |
925 | */ |
926 | unsigned iq = cfq_group_get_avg_queues(cfqd, cfqq->cfqg, |
927 | cfq_class_rt(cfqq)); |
928 | unsigned sync_slice = cfqd->cfq_slice[1]; |
929 | unsigned expect_latency = sync_slice * iq; |
930 | unsigned group_slice = cfq_group_slice(cfqd, cfqq->cfqg); |
931 | |
932 | if (expect_latency > group_slice) { |
933 | unsigned base_low_slice = 2 * cfqd->cfq_slice_idle; |
934 | /* scale low_slice according to IO priority |
935 | * and sync vs async */ |
936 | unsigned low_slice = |
937 | min(slice, base_low_slice * slice / sync_slice); |
938 | /* the adapted slice value is scaled to fit all iqs |
939 | * into the target latency */ |
940 | slice = max(slice * group_slice / expect_latency, |
941 | low_slice); |
942 | } |
943 | } |
944 | return slice; |
945 | } |
946 | |
947 | static inline void |
948 | cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
949 | { |
950 | unsigned slice = cfq_scaled_cfqq_slice(cfqd, cfqq); |
951 | |
952 | cfqq->slice_start = jiffies; |
953 | cfqq->slice_end = jiffies + slice; |
954 | cfqq->allocated_slice = slice; |
955 | cfq_log_cfqq(cfqd, cfqq, "set_slice=%lu", cfqq->slice_end - jiffies); |
956 | } |
957 | |
958 | /* |
959 | * We need to wrap this check in cfq_cfqq_slice_new(), since ->slice_end |
960 | * isn't valid until the first request from the dispatch is activated |
961 | * and the slice time set. |
962 | */ |
963 | static inline bool cfq_slice_used(struct cfq_queue *cfqq) |
964 | { |
965 | if (cfq_cfqq_slice_new(cfqq)) |
966 | return false; |
967 | if (time_before(jiffies, cfqq->slice_end)) |
968 | return false; |
969 | |
970 | return true; |
971 | } |
972 | |
973 | /* |
974 | * Lifted from AS - choose which of rq1 and rq2 that is best served now. |
975 | * We choose the request that is closest to the head right now. Distance |
976 | * behind the head is penalized and only allowed to a certain extent. |
977 | */ |
978 | static struct request * |
979 | cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2, sector_t last) |
980 | { |
981 | sector_t s1, s2, d1 = 0, d2 = 0; |
982 | unsigned long back_max; |
983 | #define CFQ_RQ1_WRAP 0x01 /* request 1 wraps */ |
984 | #define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */ |
985 | unsigned wrap = 0; /* bit mask: requests behind the disk head? */ |
986 | |
987 | if (rq1 == NULL || rq1 == rq2) |
988 | return rq2; |
989 | if (rq2 == NULL) |
990 | return rq1; |
991 | |
992 | if (rq_is_sync(rq1) != rq_is_sync(rq2)) |
993 | return rq_is_sync(rq1) ? rq1 : rq2; |
994 | |
995 | if ((rq1->cmd_flags ^ rq2->cmd_flags) & REQ_PRIO) |
996 | return rq1->cmd_flags & REQ_PRIO ? rq1 : rq2; |
997 | |
998 | s1 = blk_rq_pos(rq1); |
999 | s2 = blk_rq_pos(rq2); |
1000 | |
1001 | /* |
1002 | * by definition, 1KiB is 2 sectors |
1003 | */ |
1004 | back_max = cfqd->cfq_back_max * 2; |
1005 | |
1006 | /* |
1007 | * Strict one way elevator _except_ in the case where we allow |
1008 | * short backward seeks which are biased as twice the cost of a |
1009 | * similar forward seek. |
1010 | */ |
1011 | if (s1 >= last) |
1012 | d1 = s1 - last; |
1013 | else if (s1 + back_max >= last) |
1014 | d1 = (last - s1) * cfqd->cfq_back_penalty; |
1015 | else |
1016 | wrap |= CFQ_RQ1_WRAP; |
1017 | |
1018 | if (s2 >= last) |
1019 | d2 = s2 - last; |
1020 | else if (s2 + back_max >= last) |
1021 | d2 = (last - s2) * cfqd->cfq_back_penalty; |
1022 | else |
1023 | wrap |= CFQ_RQ2_WRAP; |
1024 | |
1025 | /* Found required data */ |
1026 | |
1027 | /* |
1028 | * By doing switch() on the bit mask "wrap" we avoid having to |
1029 | * check two variables for all permutations: --> faster! |
1030 | */ |
1031 | switch (wrap) { |
1032 | case 0: /* common case for CFQ: rq1 and rq2 not wrapped */ |
1033 | if (d1 < d2) |
1034 | return rq1; |
1035 | else if (d2 < d1) |
1036 | return rq2; |
1037 | else { |
1038 | if (s1 >= s2) |
1039 | return rq1; |
1040 | else |
1041 | return rq2; |
1042 | } |
1043 | |
1044 | case CFQ_RQ2_WRAP: |
1045 | return rq1; |
1046 | case CFQ_RQ1_WRAP: |
1047 | return rq2; |
1048 | case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both rqs wrapped */ |
1049 | default: |
1050 | /* |
1051 | * Since both rqs are wrapped, |
1052 | * start with the one that's further behind head |
1053 | * (--> only *one* back seek required), |
1054 | * since back seek takes more time than forward. |
1055 | */ |
1056 | if (s1 <= s2) |
1057 | return rq1; |
1058 | else |
1059 | return rq2; |
1060 | } |
1061 | } |
1062 | |
1063 | /* |
1064 | * The below is leftmost cache rbtree addon |
1065 | */ |
1066 | static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root) |
1067 | { |
1068 | /* Service tree is empty */ |
1069 | if (!root->count) |
1070 | return NULL; |
1071 | |
1072 | if (!root->left) |
1073 | root->left = rb_first(&root->rb); |
1074 | |
1075 | if (root->left) |
1076 | return rb_entry(root->left, struct cfq_queue, rb_node); |
1077 | |
1078 | return NULL; |
1079 | } |
1080 | |
1081 | static struct cfq_group *cfq_rb_first_group(struct cfq_rb_root *root) |
1082 | { |
1083 | if (!root->left) |
1084 | root->left = rb_first(&root->rb); |
1085 | |
1086 | if (root->left) |
1087 | return rb_entry_cfqg(root->left); |
1088 | |
1089 | return NULL; |
1090 | } |
1091 | |
1092 | static void rb_erase_init(struct rb_node *n, struct rb_root *root) |
1093 | { |
1094 | rb_erase(n, root); |
1095 | RB_CLEAR_NODE(n); |
1096 | } |
1097 | |
1098 | static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root) |
1099 | { |
1100 | if (root->left == n) |
1101 | root->left = NULL; |
1102 | rb_erase_init(n, &root->rb); |
1103 | --root->count; |
1104 | } |
1105 | |
1106 | /* |
1107 | * would be nice to take fifo expire time into account as well |
1108 | */ |
1109 | static struct request * |
1110 | cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
1111 | struct request *last) |
1112 | { |
1113 | struct rb_node *rbnext = rb_next(&last->rb_node); |
1114 | struct rb_node *rbprev = rb_prev(&last->rb_node); |
1115 | struct request *next = NULL, *prev = NULL; |
1116 | |
1117 | BUG_ON(RB_EMPTY_NODE(&last->rb_node)); |
1118 | |
1119 | if (rbprev) |
1120 | prev = rb_entry_rq(rbprev); |
1121 | |
1122 | if (rbnext) |
1123 | next = rb_entry_rq(rbnext); |
1124 | else { |
1125 | rbnext = rb_first(&cfqq->sort_list); |
1126 | if (rbnext && rbnext != &last->rb_node) |
1127 | next = rb_entry_rq(rbnext); |
1128 | } |
1129 | |
1130 | return cfq_choose_req(cfqd, next, prev, blk_rq_pos(last)); |
1131 | } |
1132 | |
1133 | static unsigned long cfq_slice_offset(struct cfq_data *cfqd, |
1134 | struct cfq_queue *cfqq) |
1135 | { |
1136 | /* |
1137 | * just an approximation, should be ok. |
1138 | */ |
1139 | return (cfqq->cfqg->nr_cfqq - 1) * (cfq_prio_slice(cfqd, 1, 0) - |
1140 | cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio)); |
1141 | } |
1142 | |
1143 | static inline s64 |
1144 | cfqg_key(struct cfq_rb_root *st, struct cfq_group *cfqg) |
1145 | { |
1146 | return cfqg->vdisktime - st->min_vdisktime; |
1147 | } |
1148 | |
1149 | static void |
1150 | __cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg) |
1151 | { |
1152 | struct rb_node **node = &st->rb.rb_node; |
1153 | struct rb_node *parent = NULL; |
1154 | struct cfq_group *__cfqg; |
1155 | s64 key = cfqg_key(st, cfqg); |
1156 | int left = 1; |
1157 | |
1158 | while (*node != NULL) { |
1159 | parent = *node; |
1160 | __cfqg = rb_entry_cfqg(parent); |
1161 | |
1162 | if (key < cfqg_key(st, __cfqg)) |
1163 | node = &parent->rb_left; |
1164 | else { |
1165 | node = &parent->rb_right; |
1166 | left = 0; |
1167 | } |
1168 | } |
1169 | |
1170 | if (left) |
1171 | st->left = &cfqg->rb_node; |
1172 | |
1173 | rb_link_node(&cfqg->rb_node, parent, node); |
1174 | rb_insert_color(&cfqg->rb_node, &st->rb); |
1175 | } |
1176 | |
1177 | static void |
1178 | cfq_update_group_weight(struct cfq_group *cfqg) |
1179 | { |
1180 | BUG_ON(!RB_EMPTY_NODE(&cfqg->rb_node)); |
1181 | if (cfqg->new_weight) { |
1182 | cfqg->weight = cfqg->new_weight; |
1183 | cfqg->new_weight = 0; |
1184 | } |
1185 | } |
1186 | |
1187 | static void |
1188 | cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg) |
1189 | { |
1190 | BUG_ON(!RB_EMPTY_NODE(&cfqg->rb_node)); |
1191 | |
1192 | cfq_update_group_weight(cfqg); |
1193 | __cfq_group_service_tree_add(st, cfqg); |
1194 | st->total_weight += cfqg->weight; |
1195 | } |
1196 | |
1197 | static void |
1198 | cfq_group_notify_queue_add(struct cfq_data *cfqd, struct cfq_group *cfqg) |
1199 | { |
1200 | struct cfq_rb_root *st = &cfqd->grp_service_tree; |
1201 | struct cfq_group *__cfqg; |
1202 | struct rb_node *n; |
1203 | |
1204 | cfqg->nr_cfqq++; |
1205 | if (!RB_EMPTY_NODE(&cfqg->rb_node)) |
1206 | return; |
1207 | |
1208 | /* |
1209 | * Currently put the group at the end. Later implement something |
1210 | * so that groups get lesser vtime based on their weights, so that |
1211 | * if group does not loose all if it was not continuously backlogged. |
1212 | */ |
1213 | n = rb_last(&st->rb); |
1214 | if (n) { |
1215 | __cfqg = rb_entry_cfqg(n); |
1216 | cfqg->vdisktime = __cfqg->vdisktime + CFQ_IDLE_DELAY; |
1217 | } else |
1218 | cfqg->vdisktime = st->min_vdisktime; |
1219 | cfq_group_service_tree_add(st, cfqg); |
1220 | } |
1221 | |
1222 | static void |
1223 | cfq_group_service_tree_del(struct cfq_rb_root *st, struct cfq_group *cfqg) |
1224 | { |
1225 | st->total_weight -= cfqg->weight; |
1226 | if (!RB_EMPTY_NODE(&cfqg->rb_node)) |
1227 | cfq_rb_erase(&cfqg->rb_node, st); |
1228 | } |
1229 | |
1230 | static void |
1231 | cfq_group_notify_queue_del(struct cfq_data *cfqd, struct cfq_group *cfqg) |
1232 | { |
1233 | struct cfq_rb_root *st = &cfqd->grp_service_tree; |
1234 | |
1235 | BUG_ON(cfqg->nr_cfqq < 1); |
1236 | cfqg->nr_cfqq--; |
1237 | |
1238 | /* If there are other cfq queues under this group, don't delete it */ |
1239 | if (cfqg->nr_cfqq) |
1240 | return; |
1241 | |
1242 | cfq_log_cfqg(cfqd, cfqg, "del_from_rr group"); |
1243 | cfq_group_service_tree_del(st, cfqg); |
1244 | cfqg->saved_workload_slice = 0; |
1245 | cfqg_stats_update_dequeue(cfqg); |
1246 | } |
1247 | |
1248 | static inline unsigned int cfq_cfqq_slice_usage(struct cfq_queue *cfqq, |
1249 | unsigned int *unaccounted_time) |
1250 | { |
1251 | unsigned int slice_used; |
1252 | |
1253 | /* |
1254 | * Queue got expired before even a single request completed or |
1255 | * got expired immediately after first request completion. |
1256 | */ |
1257 | if (!cfqq->slice_start || cfqq->slice_start == jiffies) { |
1258 | /* |
1259 | * Also charge the seek time incurred to the group, otherwise |
1260 | * if there are mutiple queues in the group, each can dispatch |
1261 | * a single request on seeky media and cause lots of seek time |
1262 | * and group will never know it. |
1263 | */ |
1264 | slice_used = max_t(unsigned, (jiffies - cfqq->dispatch_start), |
1265 | 1); |
1266 | } else { |
1267 | slice_used = jiffies - cfqq->slice_start; |
1268 | if (slice_used > cfqq->allocated_slice) { |
1269 | *unaccounted_time = slice_used - cfqq->allocated_slice; |
1270 | slice_used = cfqq->allocated_slice; |
1271 | } |
1272 | if (time_after(cfqq->slice_start, cfqq->dispatch_start)) |
1273 | *unaccounted_time += cfqq->slice_start - |
1274 | cfqq->dispatch_start; |
1275 | } |
1276 | |
1277 | return slice_used; |
1278 | } |
1279 | |
1280 | static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg, |
1281 | struct cfq_queue *cfqq) |
1282 | { |
1283 | struct cfq_rb_root *st = &cfqd->grp_service_tree; |
1284 | unsigned int used_sl, charge, unaccounted_sl = 0; |
1285 | int nr_sync = cfqg->nr_cfqq - cfqg_busy_async_queues(cfqd, cfqg) |
1286 | - cfqg->service_tree_idle.count; |
1287 | |
1288 | BUG_ON(nr_sync < 0); |
1289 | used_sl = charge = cfq_cfqq_slice_usage(cfqq, &unaccounted_sl); |
1290 | |
1291 | if (iops_mode(cfqd)) |
1292 | charge = cfqq->slice_dispatch; |
1293 | else if (!cfq_cfqq_sync(cfqq) && !nr_sync) |
1294 | charge = cfqq->allocated_slice; |
1295 | |
1296 | /* Can't update vdisktime while group is on service tree */ |
1297 | cfq_group_service_tree_del(st, cfqg); |
1298 | cfqg->vdisktime += cfq_scale_slice(charge, cfqg); |
1299 | /* If a new weight was requested, update now, off tree */ |
1300 | cfq_group_service_tree_add(st, cfqg); |
1301 | |
1302 | /* This group is being expired. Save the context */ |
1303 | if (time_after(cfqd->workload_expires, jiffies)) { |
1304 | cfqg->saved_workload_slice = cfqd->workload_expires |
1305 | - jiffies; |
1306 | cfqg->saved_workload = cfqd->serving_type; |
1307 | cfqg->saved_serving_prio = cfqd->serving_prio; |
1308 | } else |
1309 | cfqg->saved_workload_slice = 0; |
1310 | |
1311 | cfq_log_cfqg(cfqd, cfqg, "served: vt=%llu min_vt=%llu", cfqg->vdisktime, |
1312 | st->min_vdisktime); |
1313 | cfq_log_cfqq(cfqq->cfqd, cfqq, |
1314 | "sl_used=%u disp=%u charge=%u iops=%u sect=%lu", |
1315 | used_sl, cfqq->slice_dispatch, charge, |
1316 | iops_mode(cfqd), cfqq->nr_sectors); |
1317 | cfqg_stats_update_timeslice_used(cfqg, used_sl, unaccounted_sl); |
1318 | cfqg_stats_set_start_empty_time(cfqg); |
1319 | } |
1320 | |
1321 | /** |
1322 | * cfq_init_cfqg_base - initialize base part of a cfq_group |
1323 | * @cfqg: cfq_group to initialize |
1324 | * |
1325 | * Initialize the base part which is used whether %CONFIG_CFQ_GROUP_IOSCHED |
1326 | * is enabled or not. |
1327 | */ |
1328 | static void cfq_init_cfqg_base(struct cfq_group *cfqg) |
1329 | { |
1330 | struct cfq_rb_root *st; |
1331 | int i, j; |
1332 | |
1333 | for_each_cfqg_st(cfqg, i, j, st) |
1334 | *st = CFQ_RB_ROOT; |
1335 | RB_CLEAR_NODE(&cfqg->rb_node); |
1336 | |
1337 | cfqg->ttime.last_end_request = jiffies; |
1338 | } |
1339 | |
1340 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
1341 | static void cfq_pd_init(struct blkcg_gq *blkg) |
1342 | { |
1343 | struct cfq_group *cfqg = blkg_to_cfqg(blkg); |
1344 | |
1345 | cfq_init_cfqg_base(cfqg); |
1346 | cfqg->weight = blkg->blkcg->cfq_weight; |
1347 | } |
1348 | |
1349 | /* |
1350 | * Search for the cfq group current task belongs to. request_queue lock must |
1351 | * be held. |
1352 | */ |
1353 | static struct cfq_group *cfq_lookup_create_cfqg(struct cfq_data *cfqd, |
1354 | struct blkcg *blkcg) |
1355 | { |
1356 | struct request_queue *q = cfqd->queue; |
1357 | struct cfq_group *cfqg = NULL; |
1358 | |
1359 | /* avoid lookup for the common case where there's no blkcg */ |
1360 | if (blkcg == &blkcg_root) { |
1361 | cfqg = cfqd->root_group; |
1362 | } else { |
1363 | struct blkcg_gq *blkg; |
1364 | |
1365 | blkg = blkg_lookup_create(blkcg, q); |
1366 | if (!IS_ERR(blkg)) |
1367 | cfqg = blkg_to_cfqg(blkg); |
1368 | } |
1369 | |
1370 | return cfqg; |
1371 | } |
1372 | |
1373 | static void cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) |
1374 | { |
1375 | /* Currently, all async queues are mapped to root group */ |
1376 | if (!cfq_cfqq_sync(cfqq)) |
1377 | cfqg = cfqq->cfqd->root_group; |
1378 | |
1379 | cfqq->cfqg = cfqg; |
1380 | /* cfqq reference on cfqg */ |
1381 | cfqg_get(cfqg); |
1382 | } |
1383 | |
1384 | static u64 cfqg_prfill_weight_device(struct seq_file *sf, |
1385 | struct blkg_policy_data *pd, int off) |
1386 | { |
1387 | struct cfq_group *cfqg = pd_to_cfqg(pd); |
1388 | |
1389 | if (!cfqg->dev_weight) |
1390 | return 0; |
1391 | return __blkg_prfill_u64(sf, pd, cfqg->dev_weight); |
1392 | } |
1393 | |
1394 | static int cfqg_print_weight_device(struct cgroup *cgrp, struct cftype *cft, |
1395 | struct seq_file *sf) |
1396 | { |
1397 | blkcg_print_blkgs(sf, cgroup_to_blkcg(cgrp), |
1398 | cfqg_prfill_weight_device, &blkcg_policy_cfq, 0, |
1399 | false); |
1400 | return 0; |
1401 | } |
1402 | |
1403 | static int cfq_print_weight(struct cgroup *cgrp, struct cftype *cft, |
1404 | struct seq_file *sf) |
1405 | { |
1406 | seq_printf(sf, "%u\n", cgroup_to_blkcg(cgrp)->cfq_weight); |
1407 | return 0; |
1408 | } |
1409 | |
1410 | static int cfqg_set_weight_device(struct cgroup *cgrp, struct cftype *cft, |
1411 | const char *buf) |
1412 | { |
1413 | struct blkcg *blkcg = cgroup_to_blkcg(cgrp); |
1414 | struct blkg_conf_ctx ctx; |
1415 | struct cfq_group *cfqg; |
1416 | int ret; |
1417 | |
1418 | ret = blkg_conf_prep(blkcg, &blkcg_policy_cfq, buf, &ctx); |
1419 | if (ret) |
1420 | return ret; |
1421 | |
1422 | ret = -EINVAL; |
1423 | cfqg = blkg_to_cfqg(ctx.blkg); |
1424 | if (!ctx.v || (ctx.v >= CFQ_WEIGHT_MIN && ctx.v <= CFQ_WEIGHT_MAX)) { |
1425 | cfqg->dev_weight = ctx.v; |
1426 | cfqg->new_weight = cfqg->dev_weight ?: blkcg->cfq_weight; |
1427 | ret = 0; |
1428 | } |
1429 | |
1430 | blkg_conf_finish(&ctx); |
1431 | return ret; |
1432 | } |
1433 | |
1434 | static int cfq_set_weight(struct cgroup *cgrp, struct cftype *cft, u64 val) |
1435 | { |
1436 | struct blkcg *blkcg = cgroup_to_blkcg(cgrp); |
1437 | struct blkcg_gq *blkg; |
1438 | struct hlist_node *n; |
1439 | |
1440 | if (val < CFQ_WEIGHT_MIN || val > CFQ_WEIGHT_MAX) |
1441 | return -EINVAL; |
1442 | |
1443 | spin_lock_irq(&blkcg->lock); |
1444 | blkcg->cfq_weight = (unsigned int)val; |
1445 | |
1446 | hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) { |
1447 | struct cfq_group *cfqg = blkg_to_cfqg(blkg); |
1448 | |
1449 | if (cfqg && !cfqg->dev_weight) |
1450 | cfqg->new_weight = blkcg->cfq_weight; |
1451 | } |
1452 | |
1453 | spin_unlock_irq(&blkcg->lock); |
1454 | return 0; |
1455 | } |
1456 | |
1457 | static int cfqg_print_stat(struct cgroup *cgrp, struct cftype *cft, |
1458 | struct seq_file *sf) |
1459 | { |
1460 | struct blkcg *blkcg = cgroup_to_blkcg(cgrp); |
1461 | |
1462 | blkcg_print_blkgs(sf, blkcg, blkg_prfill_stat, &blkcg_policy_cfq, |
1463 | cft->private, false); |
1464 | return 0; |
1465 | } |
1466 | |
1467 | static int cfqg_print_rwstat(struct cgroup *cgrp, struct cftype *cft, |
1468 | struct seq_file *sf) |
1469 | { |
1470 | struct blkcg *blkcg = cgroup_to_blkcg(cgrp); |
1471 | |
1472 | blkcg_print_blkgs(sf, blkcg, blkg_prfill_rwstat, &blkcg_policy_cfq, |
1473 | cft->private, true); |
1474 | return 0; |
1475 | } |
1476 | |
1477 | #ifdef CONFIG_DEBUG_BLK_CGROUP |
1478 | static u64 cfqg_prfill_avg_queue_size(struct seq_file *sf, |
1479 | struct blkg_policy_data *pd, int off) |
1480 | { |
1481 | struct cfq_group *cfqg = pd_to_cfqg(pd); |
1482 | u64 samples = blkg_stat_read(&cfqg->stats.avg_queue_size_samples); |
1483 | u64 v = 0; |
1484 | |
1485 | if (samples) { |
1486 | v = blkg_stat_read(&cfqg->stats.avg_queue_size_sum); |
1487 | do_div(v, samples); |
1488 | } |
1489 | __blkg_prfill_u64(sf, pd, v); |
1490 | return 0; |
1491 | } |
1492 | |
1493 | /* print avg_queue_size */ |
1494 | static int cfqg_print_avg_queue_size(struct cgroup *cgrp, struct cftype *cft, |
1495 | struct seq_file *sf) |
1496 | { |
1497 | struct blkcg *blkcg = cgroup_to_blkcg(cgrp); |
1498 | |
1499 | blkcg_print_blkgs(sf, blkcg, cfqg_prfill_avg_queue_size, |
1500 | &blkcg_policy_cfq, 0, false); |
1501 | return 0; |
1502 | } |
1503 | #endif /* CONFIG_DEBUG_BLK_CGROUP */ |
1504 | |
1505 | static struct cftype cfq_blkcg_files[] = { |
1506 | { |
1507 | .name = "weight_device", |
1508 | .read_seq_string = cfqg_print_weight_device, |
1509 | .write_string = cfqg_set_weight_device, |
1510 | .max_write_len = 256, |
1511 | }, |
1512 | { |
1513 | .name = "weight", |
1514 | .read_seq_string = cfq_print_weight, |
1515 | .write_u64 = cfq_set_weight, |
1516 | }, |
1517 | { |
1518 | .name = "time", |
1519 | .private = offsetof(struct cfq_group, stats.time), |
1520 | .read_seq_string = cfqg_print_stat, |
1521 | }, |
1522 | { |
1523 | .name = "sectors", |
1524 | .private = offsetof(struct cfq_group, stats.sectors), |
1525 | .read_seq_string = cfqg_print_stat, |
1526 | }, |
1527 | { |
1528 | .name = "io_service_bytes", |
1529 | .private = offsetof(struct cfq_group, stats.service_bytes), |
1530 | .read_seq_string = cfqg_print_rwstat, |
1531 | }, |
1532 | { |
1533 | .name = "io_serviced", |
1534 | .private = offsetof(struct cfq_group, stats.serviced), |
1535 | .read_seq_string = cfqg_print_rwstat, |
1536 | }, |
1537 | { |
1538 | .name = "io_service_time", |
1539 | .private = offsetof(struct cfq_group, stats.service_time), |
1540 | .read_seq_string = cfqg_print_rwstat, |
1541 | }, |
1542 | { |
1543 | .name = "io_wait_time", |
1544 | .private = offsetof(struct cfq_group, stats.wait_time), |
1545 | .read_seq_string = cfqg_print_rwstat, |
1546 | }, |
1547 | { |
1548 | .name = "io_merged", |
1549 | .private = offsetof(struct cfq_group, stats.merged), |
1550 | .read_seq_string = cfqg_print_rwstat, |
1551 | }, |
1552 | { |
1553 | .name = "io_queued", |
1554 | .private = offsetof(struct cfq_group, stats.queued), |
1555 | .read_seq_string = cfqg_print_rwstat, |
1556 | }, |
1557 | #ifdef CONFIG_DEBUG_BLK_CGROUP |
1558 | { |
1559 | .name = "avg_queue_size", |
1560 | .read_seq_string = cfqg_print_avg_queue_size, |
1561 | }, |
1562 | { |
1563 | .name = "group_wait_time", |
1564 | .private = offsetof(struct cfq_group, stats.group_wait_time), |
1565 | .read_seq_string = cfqg_print_stat, |
1566 | }, |
1567 | { |
1568 | .name = "idle_time", |
1569 | .private = offsetof(struct cfq_group, stats.idle_time), |
1570 | .read_seq_string = cfqg_print_stat, |
1571 | }, |
1572 | { |
1573 | .name = "empty_time", |
1574 | .private = offsetof(struct cfq_group, stats.empty_time), |
1575 | .read_seq_string = cfqg_print_stat, |
1576 | }, |
1577 | { |
1578 | .name = "dequeue", |
1579 | .private = offsetof(struct cfq_group, stats.dequeue), |
1580 | .read_seq_string = cfqg_print_stat, |
1581 | }, |
1582 | { |
1583 | .name = "unaccounted_time", |
1584 | .private = offsetof(struct cfq_group, stats.unaccounted_time), |
1585 | .read_seq_string = cfqg_print_stat, |
1586 | }, |
1587 | #endif /* CONFIG_DEBUG_BLK_CGROUP */ |
1588 | { } /* terminate */ |
1589 | }; |
1590 | #else /* GROUP_IOSCHED */ |
1591 | static struct cfq_group *cfq_lookup_create_cfqg(struct cfq_data *cfqd, |
1592 | struct blkcg *blkcg) |
1593 | { |
1594 | return cfqd->root_group; |
1595 | } |
1596 | |
1597 | static inline void |
1598 | cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) { |
1599 | cfqq->cfqg = cfqg; |
1600 | } |
1601 | |
1602 | #endif /* GROUP_IOSCHED */ |
1603 | |
1604 | /* |
1605 | * The cfqd->service_trees holds all pending cfq_queue's that have |
1606 | * requests waiting to be processed. It is sorted in the order that |
1607 | * we will service the queues. |
1608 | */ |
1609 | static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
1610 | bool add_front) |
1611 | { |
1612 | struct rb_node **p, *parent; |
1613 | struct cfq_queue *__cfqq; |
1614 | unsigned long rb_key; |
1615 | struct cfq_rb_root *service_tree; |
1616 | int left; |
1617 | int new_cfqq = 1; |
1618 | |
1619 | service_tree = service_tree_for(cfqq->cfqg, cfqq_prio(cfqq), |
1620 | cfqq_type(cfqq)); |
1621 | if (cfq_class_idle(cfqq)) { |
1622 | rb_key = CFQ_IDLE_DELAY; |
1623 | parent = rb_last(&service_tree->rb); |
1624 | if (parent && parent != &cfqq->rb_node) { |
1625 | __cfqq = rb_entry(parent, struct cfq_queue, rb_node); |
1626 | rb_key += __cfqq->rb_key; |
1627 | } else |
1628 | rb_key += jiffies; |
1629 | } else if (!add_front) { |
1630 | /* |
1631 | * Get our rb key offset. Subtract any residual slice |
1632 | * value carried from last service. A negative resid |
1633 | * count indicates slice overrun, and this should position |
1634 | * the next service time further away in the tree. |
1635 | */ |
1636 | rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies; |
1637 | rb_key -= cfqq->slice_resid; |
1638 | cfqq->slice_resid = 0; |
1639 | } else { |
1640 | rb_key = -HZ; |
1641 | __cfqq = cfq_rb_first(service_tree); |
1642 | rb_key += __cfqq ? __cfqq->rb_key : jiffies; |
1643 | } |
1644 | |
1645 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) { |
1646 | new_cfqq = 0; |
1647 | /* |
1648 | * same position, nothing more to do |
1649 | */ |
1650 | if (rb_key == cfqq->rb_key && |
1651 | cfqq->service_tree == service_tree) |
1652 | return; |
1653 | |
1654 | cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree); |
1655 | cfqq->service_tree = NULL; |
1656 | } |
1657 | |
1658 | left = 1; |
1659 | parent = NULL; |
1660 | cfqq->service_tree = service_tree; |
1661 | p = &service_tree->rb.rb_node; |
1662 | while (*p) { |
1663 | struct rb_node **n; |
1664 | |
1665 | parent = *p; |
1666 | __cfqq = rb_entry(parent, struct cfq_queue, rb_node); |
1667 | |
1668 | /* |
1669 | * sort by key, that represents service time. |
1670 | */ |
1671 | if (time_before(rb_key, __cfqq->rb_key)) |
1672 | n = &(*p)->rb_left; |
1673 | else { |
1674 | n = &(*p)->rb_right; |
1675 | left = 0; |
1676 | } |
1677 | |
1678 | p = n; |
1679 | } |
1680 | |
1681 | if (left) |
1682 | service_tree->left = &cfqq->rb_node; |
1683 | |
1684 | cfqq->rb_key = rb_key; |
1685 | rb_link_node(&cfqq->rb_node, parent, p); |
1686 | rb_insert_color(&cfqq->rb_node, &service_tree->rb); |
1687 | service_tree->count++; |
1688 | if (add_front || !new_cfqq) |
1689 | return; |
1690 | cfq_group_notify_queue_add(cfqd, cfqq->cfqg); |
1691 | } |
1692 | |
1693 | static struct cfq_queue * |
1694 | cfq_prio_tree_lookup(struct cfq_data *cfqd, struct rb_root *root, |
1695 | sector_t sector, struct rb_node **ret_parent, |
1696 | struct rb_node ***rb_link) |
1697 | { |
1698 | struct rb_node **p, *parent; |
1699 | struct cfq_queue *cfqq = NULL; |
1700 | |
1701 | parent = NULL; |
1702 | p = &root->rb_node; |
1703 | while (*p) { |
1704 | struct rb_node **n; |
1705 | |
1706 | parent = *p; |
1707 | cfqq = rb_entry(parent, struct cfq_queue, p_node); |
1708 | |
1709 | /* |
1710 | * Sort strictly based on sector. Smallest to the left, |
1711 | * largest to the right. |
1712 | */ |
1713 | if (sector > blk_rq_pos(cfqq->next_rq)) |
1714 | n = &(*p)->rb_right; |
1715 | else if (sector < blk_rq_pos(cfqq->next_rq)) |
1716 | n = &(*p)->rb_left; |
1717 | else |
1718 | break; |
1719 | p = n; |
1720 | cfqq = NULL; |
1721 | } |
1722 | |
1723 | *ret_parent = parent; |
1724 | if (rb_link) |
1725 | *rb_link = p; |
1726 | return cfqq; |
1727 | } |
1728 | |
1729 | static void cfq_prio_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1730 | { |
1731 | struct rb_node **p, *parent; |
1732 | struct cfq_queue *__cfqq; |
1733 | |
1734 | if (cfqq->p_root) { |
1735 | rb_erase(&cfqq->p_node, cfqq->p_root); |
1736 | cfqq->p_root = NULL; |
1737 | } |
1738 | |
1739 | if (cfq_class_idle(cfqq)) |
1740 | return; |
1741 | if (!cfqq->next_rq) |
1742 | return; |
1743 | |
1744 | cfqq->p_root = &cfqd->prio_trees[cfqq->org_ioprio]; |
1745 | __cfqq = cfq_prio_tree_lookup(cfqd, cfqq->p_root, |
1746 | blk_rq_pos(cfqq->next_rq), &parent, &p); |
1747 | if (!__cfqq) { |
1748 | rb_link_node(&cfqq->p_node, parent, p); |
1749 | rb_insert_color(&cfqq->p_node, cfqq->p_root); |
1750 | } else |
1751 | cfqq->p_root = NULL; |
1752 | } |
1753 | |
1754 | /* |
1755 | * Update cfqq's position in the service tree. |
1756 | */ |
1757 | static void cfq_resort_rr_list(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1758 | { |
1759 | /* |
1760 | * Resorting requires the cfqq to be on the RR list already. |
1761 | */ |
1762 | if (cfq_cfqq_on_rr(cfqq)) { |
1763 | cfq_service_tree_add(cfqd, cfqq, 0); |
1764 | cfq_prio_tree_add(cfqd, cfqq); |
1765 | } |
1766 | } |
1767 | |
1768 | /* |
1769 | * add to busy list of queues for service, trying to be fair in ordering |
1770 | * the pending list according to last request service |
1771 | */ |
1772 | static void cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1773 | { |
1774 | cfq_log_cfqq(cfqd, cfqq, "add_to_rr"); |
1775 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
1776 | cfq_mark_cfqq_on_rr(cfqq); |
1777 | cfqd->busy_queues++; |
1778 | if (cfq_cfqq_sync(cfqq)) |
1779 | cfqd->busy_sync_queues++; |
1780 | |
1781 | cfq_resort_rr_list(cfqd, cfqq); |
1782 | } |
1783 | |
1784 | /* |
1785 | * Called when the cfqq no longer has requests pending, remove it from |
1786 | * the service tree. |
1787 | */ |
1788 | static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1789 | { |
1790 | cfq_log_cfqq(cfqd, cfqq, "del_from_rr"); |
1791 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
1792 | cfq_clear_cfqq_on_rr(cfqq); |
1793 | |
1794 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) { |
1795 | cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree); |
1796 | cfqq->service_tree = NULL; |
1797 | } |
1798 | if (cfqq->p_root) { |
1799 | rb_erase(&cfqq->p_node, cfqq->p_root); |
1800 | cfqq->p_root = NULL; |
1801 | } |
1802 | |
1803 | cfq_group_notify_queue_del(cfqd, cfqq->cfqg); |
1804 | BUG_ON(!cfqd->busy_queues); |
1805 | cfqd->busy_queues--; |
1806 | if (cfq_cfqq_sync(cfqq)) |
1807 | cfqd->busy_sync_queues--; |
1808 | } |
1809 | |
1810 | /* |
1811 | * rb tree support functions |
1812 | */ |
1813 | static void cfq_del_rq_rb(struct request *rq) |
1814 | { |
1815 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
1816 | const int sync = rq_is_sync(rq); |
1817 | |
1818 | BUG_ON(!cfqq->queued[sync]); |
1819 | cfqq->queued[sync]--; |
1820 | |
1821 | elv_rb_del(&cfqq->sort_list, rq); |
1822 | |
1823 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) { |
1824 | /* |
1825 | * Queue will be deleted from service tree when we actually |
1826 | * expire it later. Right now just remove it from prio tree |
1827 | * as it is empty. |
1828 | */ |
1829 | if (cfqq->p_root) { |
1830 | rb_erase(&cfqq->p_node, cfqq->p_root); |
1831 | cfqq->p_root = NULL; |
1832 | } |
1833 | } |
1834 | } |
1835 | |
1836 | static void cfq_add_rq_rb(struct request *rq) |
1837 | { |
1838 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
1839 | struct cfq_data *cfqd = cfqq->cfqd; |
1840 | struct request *prev; |
1841 | |
1842 | cfqq->queued[rq_is_sync(rq)]++; |
1843 | |
1844 | elv_rb_add(&cfqq->sort_list, rq); |
1845 | |
1846 | if (!cfq_cfqq_on_rr(cfqq)) |
1847 | cfq_add_cfqq_rr(cfqd, cfqq); |
1848 | |
1849 | /* |
1850 | * check if this request is a better next-serve candidate |
1851 | */ |
1852 | prev = cfqq->next_rq; |
1853 | cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq, cfqd->last_position); |
1854 | |
1855 | /* |
1856 | * adjust priority tree position, if ->next_rq changes |
1857 | */ |
1858 | if (prev != cfqq->next_rq) |
1859 | cfq_prio_tree_add(cfqd, cfqq); |
1860 | |
1861 | BUG_ON(!cfqq->next_rq); |
1862 | } |
1863 | |
1864 | static void cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq) |
1865 | { |
1866 | elv_rb_del(&cfqq->sort_list, rq); |
1867 | cfqq->queued[rq_is_sync(rq)]--; |
1868 | cfqg_stats_update_io_remove(RQ_CFQG(rq), rq->cmd_flags); |
1869 | cfq_add_rq_rb(rq); |
1870 | cfqg_stats_update_io_add(RQ_CFQG(rq), cfqq->cfqd->serving_group, |
1871 | rq->cmd_flags); |
1872 | } |
1873 | |
1874 | static struct request * |
1875 | cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio) |
1876 | { |
1877 | struct task_struct *tsk = current; |
1878 | struct cfq_io_cq *cic; |
1879 | struct cfq_queue *cfqq; |
1880 | |
1881 | cic = cfq_cic_lookup(cfqd, tsk->io_context); |
1882 | if (!cic) |
1883 | return NULL; |
1884 | |
1885 | cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); |
1886 | if (cfqq) { |
1887 | sector_t sector = bio->bi_sector + bio_sectors(bio); |
1888 | |
1889 | return elv_rb_find(&cfqq->sort_list, sector); |
1890 | } |
1891 | |
1892 | return NULL; |
1893 | } |
1894 | |
1895 | static void cfq_activate_request(struct request_queue *q, struct request *rq) |
1896 | { |
1897 | struct cfq_data *cfqd = q->elevator->elevator_data; |
1898 | |
1899 | cfqd->rq_in_driver++; |
1900 | cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "activate rq, drv=%d", |
1901 | cfqd->rq_in_driver); |
1902 | |
1903 | cfqd->last_position = blk_rq_pos(rq) + blk_rq_sectors(rq); |
1904 | } |
1905 | |
1906 | static void cfq_deactivate_request(struct request_queue *q, struct request *rq) |
1907 | { |
1908 | struct cfq_data *cfqd = q->elevator->elevator_data; |
1909 | |
1910 | WARN_ON(!cfqd->rq_in_driver); |
1911 | cfqd->rq_in_driver--; |
1912 | cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "deactivate rq, drv=%d", |
1913 | cfqd->rq_in_driver); |
1914 | } |
1915 | |
1916 | static void cfq_remove_request(struct request *rq) |
1917 | { |
1918 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
1919 | |
1920 | if (cfqq->next_rq == rq) |
1921 | cfqq->next_rq = cfq_find_next_rq(cfqq->cfqd, cfqq, rq); |
1922 | |
1923 | list_del_init(&rq->queuelist); |
1924 | cfq_del_rq_rb(rq); |
1925 | |
1926 | cfqq->cfqd->rq_queued--; |
1927 | cfqg_stats_update_io_remove(RQ_CFQG(rq), rq->cmd_flags); |
1928 | if (rq->cmd_flags & REQ_PRIO) { |
1929 | WARN_ON(!cfqq->prio_pending); |
1930 | cfqq->prio_pending--; |
1931 | } |
1932 | } |
1933 | |
1934 | static int cfq_merge(struct request_queue *q, struct request **req, |
1935 | struct bio *bio) |
1936 | { |
1937 | struct cfq_data *cfqd = q->elevator->elevator_data; |
1938 | struct request *__rq; |
1939 | |
1940 | __rq = cfq_find_rq_fmerge(cfqd, bio); |
1941 | if (__rq && elv_rq_merge_ok(__rq, bio)) { |
1942 | *req = __rq; |
1943 | return ELEVATOR_FRONT_MERGE; |
1944 | } |
1945 | |
1946 | return ELEVATOR_NO_MERGE; |
1947 | } |
1948 | |
1949 | static void cfq_merged_request(struct request_queue *q, struct request *req, |
1950 | int type) |
1951 | { |
1952 | if (type == ELEVATOR_FRONT_MERGE) { |
1953 | struct cfq_queue *cfqq = RQ_CFQQ(req); |
1954 | |
1955 | cfq_reposition_rq_rb(cfqq, req); |
1956 | } |
1957 | } |
1958 | |
1959 | static void cfq_bio_merged(struct request_queue *q, struct request *req, |
1960 | struct bio *bio) |
1961 | { |
1962 | cfqg_stats_update_io_merged(RQ_CFQG(req), bio->bi_rw); |
1963 | } |
1964 | |
1965 | static void |
1966 | cfq_merged_requests(struct request_queue *q, struct request *rq, |
1967 | struct request *next) |
1968 | { |
1969 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
1970 | struct cfq_data *cfqd = q->elevator->elevator_data; |
1971 | |
1972 | /* |
1973 | * reposition in fifo if next is older than rq |
1974 | */ |
1975 | if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && |
1976 | time_before(rq_fifo_time(next), rq_fifo_time(rq))) { |
1977 | list_move(&rq->queuelist, &next->queuelist); |
1978 | rq_set_fifo_time(rq, rq_fifo_time(next)); |
1979 | } |
1980 | |
1981 | if (cfqq->next_rq == next) |
1982 | cfqq->next_rq = rq; |
1983 | cfq_remove_request(next); |
1984 | cfqg_stats_update_io_merged(RQ_CFQG(rq), next->cmd_flags); |
1985 | |
1986 | cfqq = RQ_CFQQ(next); |
1987 | /* |
1988 | * all requests of this queue are merged to other queues, delete it |
1989 | * from the service tree. If it's the active_queue, |
1990 | * cfq_dispatch_requests() will choose to expire it or do idle |
1991 | */ |
1992 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list) && |
1993 | cfqq != cfqd->active_queue) |
1994 | cfq_del_cfqq_rr(cfqd, cfqq); |
1995 | } |
1996 | |
1997 | static int cfq_allow_merge(struct request_queue *q, struct request *rq, |
1998 | struct bio *bio) |
1999 | { |
2000 | struct cfq_data *cfqd = q->elevator->elevator_data; |
2001 | struct cfq_io_cq *cic; |
2002 | struct cfq_queue *cfqq; |
2003 | |
2004 | /* |
2005 | * Disallow merge of a sync bio into an async request. |
2006 | */ |
2007 | if (cfq_bio_sync(bio) && !rq_is_sync(rq)) |
2008 | return false; |
2009 | |
2010 | /* |
2011 | * Lookup the cfqq that this bio will be queued with and allow |
2012 | * merge only if rq is queued there. |
2013 | */ |
2014 | cic = cfq_cic_lookup(cfqd, current->io_context); |
2015 | if (!cic) |
2016 | return false; |
2017 | |
2018 | cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); |
2019 | return cfqq == RQ_CFQQ(rq); |
2020 | } |
2021 | |
2022 | static inline void cfq_del_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
2023 | { |
2024 | del_timer(&cfqd->idle_slice_timer); |
2025 | cfqg_stats_update_idle_time(cfqq->cfqg); |
2026 | } |
2027 | |
2028 | static void __cfq_set_active_queue(struct cfq_data *cfqd, |
2029 | struct cfq_queue *cfqq) |
2030 | { |
2031 | if (cfqq) { |
2032 | cfq_log_cfqq(cfqd, cfqq, "set_active wl_prio:%d wl_type:%d", |
2033 | cfqd->serving_prio, cfqd->serving_type); |
2034 | cfqg_stats_update_avg_queue_size(cfqq->cfqg); |
2035 | cfqq->slice_start = 0; |
2036 | cfqq->dispatch_start = jiffies; |
2037 | cfqq->allocated_slice = 0; |
2038 | cfqq->slice_end = 0; |
2039 | cfqq->slice_dispatch = 0; |
2040 | cfqq->nr_sectors = 0; |
2041 | |
2042 | cfq_clear_cfqq_wait_request(cfqq); |
2043 | cfq_clear_cfqq_must_dispatch(cfqq); |
2044 | cfq_clear_cfqq_must_alloc_slice(cfqq); |
2045 | cfq_clear_cfqq_fifo_expire(cfqq); |
2046 | cfq_mark_cfqq_slice_new(cfqq); |
2047 | |
2048 | cfq_del_timer(cfqd, cfqq); |
2049 | } |
2050 | |
2051 | cfqd->active_queue = cfqq; |
2052 | } |
2053 | |
2054 | /* |
2055 | * current cfqq expired its slice (or was too idle), select new one |
2056 | */ |
2057 | static void |
2058 | __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
2059 | bool timed_out) |
2060 | { |
2061 | cfq_log_cfqq(cfqd, cfqq, "slice expired t=%d", timed_out); |
2062 | |
2063 | if (cfq_cfqq_wait_request(cfqq)) |
2064 | cfq_del_timer(cfqd, cfqq); |
2065 | |
2066 | cfq_clear_cfqq_wait_request(cfqq); |
2067 | cfq_clear_cfqq_wait_busy(cfqq); |
2068 | |
2069 | /* |
2070 | * If this cfqq is shared between multiple processes, check to |
2071 | * make sure that those processes are still issuing I/Os within |
2072 | * the mean seek distance. If not, it may be time to break the |
2073 | * queues apart again. |
2074 | */ |
2075 | if (cfq_cfqq_coop(cfqq) && CFQQ_SEEKY(cfqq)) |
2076 | cfq_mark_cfqq_split_coop(cfqq); |
2077 | |
2078 | /* |
2079 | * store what was left of this slice, if the queue idled/timed out |
2080 | */ |
2081 | if (timed_out) { |
2082 | if (cfq_cfqq_slice_new(cfqq)) |
2083 | cfqq->slice_resid = cfq_scaled_cfqq_slice(cfqd, cfqq); |
2084 | else |
2085 | cfqq->slice_resid = cfqq->slice_end - jiffies; |
2086 | cfq_log_cfqq(cfqd, cfqq, "resid=%ld", cfqq->slice_resid); |
2087 | } |
2088 | |
2089 | cfq_group_served(cfqd, cfqq->cfqg, cfqq); |
2090 | |
2091 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) |
2092 | cfq_del_cfqq_rr(cfqd, cfqq); |
2093 | |
2094 | cfq_resort_rr_list(cfqd, cfqq); |
2095 | |
2096 | if (cfqq == cfqd->active_queue) |
2097 | cfqd->active_queue = NULL; |
2098 | |
2099 | if (cfqd->active_cic) { |
2100 | put_io_context(cfqd->active_cic->icq.ioc); |
2101 | cfqd->active_cic = NULL; |
2102 | } |
2103 | } |
2104 | |
2105 | static inline void cfq_slice_expired(struct cfq_data *cfqd, bool timed_out) |
2106 | { |
2107 | struct cfq_queue *cfqq = cfqd->active_queue; |
2108 | |
2109 | if (cfqq) |
2110 | __cfq_slice_expired(cfqd, cfqq, timed_out); |
2111 | } |
2112 | |
2113 | /* |
2114 | * Get next queue for service. Unless we have a queue preemption, |
2115 | * we'll simply select the first cfqq in the service tree. |
2116 | */ |
2117 | static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd) |
2118 | { |
2119 | struct cfq_rb_root *service_tree = |
2120 | service_tree_for(cfqd->serving_group, cfqd->serving_prio, |
2121 | cfqd->serving_type); |
2122 | |
2123 | if (!cfqd->rq_queued) |
2124 | return NULL; |
2125 | |
2126 | /* There is nothing to dispatch */ |
2127 | if (!service_tree) |
2128 | return NULL; |
2129 | if (RB_EMPTY_ROOT(&service_tree->rb)) |
2130 | return NULL; |
2131 | return cfq_rb_first(service_tree); |
2132 | } |
2133 | |
2134 | static struct cfq_queue *cfq_get_next_queue_forced(struct cfq_data *cfqd) |
2135 | { |
2136 | struct cfq_group *cfqg; |
2137 | struct cfq_queue *cfqq; |
2138 | int i, j; |
2139 | struct cfq_rb_root *st; |
2140 | |
2141 | if (!cfqd->rq_queued) |
2142 | return NULL; |
2143 | |
2144 | cfqg = cfq_get_next_cfqg(cfqd); |
2145 | if (!cfqg) |
2146 | return NULL; |
2147 | |
2148 | for_each_cfqg_st(cfqg, i, j, st) |
2149 | if ((cfqq = cfq_rb_first(st)) != NULL) |
2150 | return cfqq; |
2151 | return NULL; |
2152 | } |
2153 | |
2154 | /* |
2155 | * Get and set a new active queue for service. |
2156 | */ |
2157 | static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd, |
2158 | struct cfq_queue *cfqq) |
2159 | { |
2160 | if (!cfqq) |
2161 | cfqq = cfq_get_next_queue(cfqd); |
2162 | |
2163 | __cfq_set_active_queue(cfqd, cfqq); |
2164 | return cfqq; |
2165 | } |
2166 | |
2167 | static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd, |
2168 | struct request *rq) |
2169 | { |
2170 | if (blk_rq_pos(rq) >= cfqd->last_position) |
2171 | return blk_rq_pos(rq) - cfqd->last_position; |
2172 | else |
2173 | return cfqd->last_position - blk_rq_pos(rq); |
2174 | } |
2175 | |
2176 | static inline int cfq_rq_close(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
2177 | struct request *rq) |
2178 | { |
2179 | return cfq_dist_from_last(cfqd, rq) <= CFQQ_CLOSE_THR; |
2180 | } |
2181 | |
2182 | static struct cfq_queue *cfqq_close(struct cfq_data *cfqd, |
2183 | struct cfq_queue *cur_cfqq) |
2184 | { |
2185 | struct rb_root *root = &cfqd->prio_trees[cur_cfqq->org_ioprio]; |
2186 | struct rb_node *parent, *node; |
2187 | struct cfq_queue *__cfqq; |
2188 | sector_t sector = cfqd->last_position; |
2189 | |
2190 | if (RB_EMPTY_ROOT(root)) |
2191 | return NULL; |
2192 | |
2193 | /* |
2194 | * First, if we find a request starting at the end of the last |
2195 | * request, choose it. |
2196 | */ |
2197 | __cfqq = cfq_prio_tree_lookup(cfqd, root, sector, &parent, NULL); |
2198 | if (__cfqq) |
2199 | return __cfqq; |
2200 | |
2201 | /* |
2202 | * If the exact sector wasn't found, the parent of the NULL leaf |
2203 | * will contain the closest sector. |
2204 | */ |
2205 | __cfqq = rb_entry(parent, struct cfq_queue, p_node); |
2206 | if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq)) |
2207 | return __cfqq; |
2208 | |
2209 | if (blk_rq_pos(__cfqq->next_rq) < sector) |
2210 | node = rb_next(&__cfqq->p_node); |
2211 | else |
2212 | node = rb_prev(&__cfqq->p_node); |
2213 | if (!node) |
2214 | return NULL; |
2215 | |
2216 | __cfqq = rb_entry(node, struct cfq_queue, p_node); |
2217 | if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq)) |
2218 | return __cfqq; |
2219 | |
2220 | return NULL; |
2221 | } |
2222 | |
2223 | /* |
2224 | * cfqd - obvious |
2225 | * cur_cfqq - passed in so that we don't decide that the current queue is |
2226 | * closely cooperating with itself. |
2227 | * |
2228 | * So, basically we're assuming that that cur_cfqq has dispatched at least |
2229 | * one request, and that cfqd->last_position reflects a position on the disk |
2230 | * associated with the I/O issued by cur_cfqq. I'm not sure this is a valid |
2231 | * assumption. |
2232 | */ |
2233 | static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd, |
2234 | struct cfq_queue *cur_cfqq) |
2235 | { |
2236 | struct cfq_queue *cfqq; |
2237 | |
2238 | if (cfq_class_idle(cur_cfqq)) |
2239 | return NULL; |
2240 | if (!cfq_cfqq_sync(cur_cfqq)) |
2241 | return NULL; |
2242 | if (CFQQ_SEEKY(cur_cfqq)) |
2243 | return NULL; |
2244 | |
2245 | /* |
2246 | * Don't search priority tree if it's the only queue in the group. |
2247 | */ |
2248 | if (cur_cfqq->cfqg->nr_cfqq == 1) |
2249 | return NULL; |
2250 | |
2251 | /* |
2252 | * We should notice if some of the queues are cooperating, eg |
2253 | * working closely on the same area of the disk. In that case, |
2254 | * we can group them together and don't waste time idling. |
2255 | */ |
2256 | cfqq = cfqq_close(cfqd, cur_cfqq); |
2257 | if (!cfqq) |
2258 | return NULL; |
2259 | |
2260 | /* If new queue belongs to different cfq_group, don't choose it */ |
2261 | if (cur_cfqq->cfqg != cfqq->cfqg) |
2262 | return NULL; |
2263 | |
2264 | /* |
2265 | * It only makes sense to merge sync queues. |
2266 | */ |
2267 | if (!cfq_cfqq_sync(cfqq)) |
2268 | return NULL; |
2269 | if (CFQQ_SEEKY(cfqq)) |
2270 | return NULL; |
2271 | |
2272 | /* |
2273 | * Do not merge queues of different priority classes |
2274 | */ |
2275 | if (cfq_class_rt(cfqq) != cfq_class_rt(cur_cfqq)) |
2276 | return NULL; |
2277 | |
2278 | return cfqq; |
2279 | } |
2280 | |
2281 | /* |
2282 | * Determine whether we should enforce idle window for this queue. |
2283 | */ |
2284 | |
2285 | static bool cfq_should_idle(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
2286 | { |
2287 | enum wl_prio_t prio = cfqq_prio(cfqq); |
2288 | struct cfq_rb_root *service_tree = cfqq->service_tree; |
2289 | |
2290 | BUG_ON(!service_tree); |
2291 | BUG_ON(!service_tree->count); |
2292 | |
2293 | if (!cfqd->cfq_slice_idle) |
2294 | return false; |
2295 | |
2296 | /* We never do for idle class queues. */ |
2297 | if (prio == IDLE_WORKLOAD) |
2298 | return false; |
2299 | |
2300 | /* We do for queues that were marked with idle window flag. */ |
2301 | if (cfq_cfqq_idle_window(cfqq) && |
2302 | !(blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag)) |
2303 | return true; |
2304 | |
2305 | /* |
2306 | * Otherwise, we do only if they are the last ones |
2307 | * in their service tree. |
2308 | */ |
2309 | if (service_tree->count == 1 && cfq_cfqq_sync(cfqq) && |
2310 | !cfq_io_thinktime_big(cfqd, &service_tree->ttime, false)) |
2311 | return true; |
2312 | cfq_log_cfqq(cfqd, cfqq, "Not idling. st->count:%d", |
2313 | service_tree->count); |
2314 | return false; |
2315 | } |
2316 | |
2317 | static void cfq_arm_slice_timer(struct cfq_data *cfqd) |
2318 | { |
2319 | struct cfq_queue *cfqq = cfqd->active_queue; |
2320 | struct cfq_io_cq *cic; |
2321 | unsigned long sl, group_idle = 0; |
2322 | |
2323 | /* |
2324 | * SSD device without seek penalty, disable idling. But only do so |
2325 | * for devices that support queuing, otherwise we still have a problem |
2326 | * with sync vs async workloads. |
2327 | */ |
2328 | if (blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag) |
2329 | return; |
2330 | |
2331 | WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list)); |
2332 | WARN_ON(cfq_cfqq_slice_new(cfqq)); |
2333 | |
2334 | /* |
2335 | * idle is disabled, either manually or by past process history |
2336 | */ |
2337 | if (!cfq_should_idle(cfqd, cfqq)) { |
2338 | /* no queue idling. Check for group idling */ |
2339 | if (cfqd->cfq_group_idle) |
2340 | group_idle = cfqd->cfq_group_idle; |
2341 | else |
2342 | return; |
2343 | } |
2344 | |
2345 | /* |
2346 | * still active requests from this queue, don't idle |
2347 | */ |
2348 | if (cfqq->dispatched) |
2349 | return; |
2350 | |
2351 | /* |
2352 | * task has exited, don't wait |
2353 | */ |
2354 | cic = cfqd->active_cic; |
2355 | if (!cic || !atomic_read(&cic->icq.ioc->active_ref)) |
2356 | return; |
2357 | |
2358 | /* |
2359 | * If our average think time is larger than the remaining time |
2360 | * slice, then don't idle. This avoids overrunning the allotted |
2361 | * time slice. |
2362 | */ |
2363 | if (sample_valid(cic->ttime.ttime_samples) && |
2364 | (cfqq->slice_end - jiffies < cic->ttime.ttime_mean)) { |
2365 | cfq_log_cfqq(cfqd, cfqq, "Not idling. think_time:%lu", |
2366 | cic->ttime.ttime_mean); |
2367 | return; |
2368 | } |
2369 | |
2370 | /* There are other queues in the group, don't do group idle */ |
2371 | if (group_idle && cfqq->cfqg->nr_cfqq > 1) |
2372 | return; |
2373 | |
2374 | cfq_mark_cfqq_wait_request(cfqq); |
2375 | |
2376 | if (group_idle) |
2377 | sl = cfqd->cfq_group_idle; |
2378 | else |
2379 | sl = cfqd->cfq_slice_idle; |
2380 | |
2381 | mod_timer(&cfqd->idle_slice_timer, jiffies + sl); |
2382 | cfqg_stats_set_start_idle_time(cfqq->cfqg); |
2383 | cfq_log_cfqq(cfqd, cfqq, "arm_idle: %lu group_idle: %d", sl, |
2384 | group_idle ? 1 : 0); |
2385 | } |
2386 | |
2387 | /* |
2388 | * Move request from internal lists to the request queue dispatch list. |
2389 | */ |
2390 | static void cfq_dispatch_insert(struct request_queue *q, struct request *rq) |
2391 | { |
2392 | struct cfq_data *cfqd = q->elevator->elevator_data; |
2393 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
2394 | |
2395 | cfq_log_cfqq(cfqd, cfqq, "dispatch_insert"); |
2396 | |
2397 | cfqq->next_rq = cfq_find_next_rq(cfqd, cfqq, rq); |
2398 | cfq_remove_request(rq); |
2399 | cfqq->dispatched++; |
2400 | (RQ_CFQG(rq))->dispatched++; |
2401 | elv_dispatch_sort(q, rq); |
2402 | |
2403 | cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]++; |
2404 | cfqq->nr_sectors += blk_rq_sectors(rq); |
2405 | cfqg_stats_update_dispatch(cfqq->cfqg, blk_rq_bytes(rq), rq->cmd_flags); |
2406 | } |
2407 | |
2408 | /* |
2409 | * return expired entry, or NULL to just start from scratch in rbtree |
2410 | */ |
2411 | static struct request *cfq_check_fifo(struct cfq_queue *cfqq) |
2412 | { |
2413 | struct request *rq = NULL; |
2414 | |
2415 | if (cfq_cfqq_fifo_expire(cfqq)) |
2416 | return NULL; |
2417 | |
2418 | cfq_mark_cfqq_fifo_expire(cfqq); |
2419 | |
2420 | if (list_empty(&cfqq->fifo)) |
2421 | return NULL; |
2422 | |
2423 | rq = rq_entry_fifo(cfqq->fifo.next); |
2424 | if (time_before(jiffies, rq_fifo_time(rq))) |
2425 | rq = NULL; |
2426 | |
2427 | cfq_log_cfqq(cfqq->cfqd, cfqq, "fifo=%p", rq); |
2428 | return rq; |
2429 | } |
2430 | |
2431 | static inline int |
2432 | cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
2433 | { |
2434 | const int base_rq = cfqd->cfq_slice_async_rq; |
2435 | |
2436 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); |
2437 | |
2438 | return 2 * base_rq * (IOPRIO_BE_NR - cfqq->ioprio); |
2439 | } |
2440 | |
2441 | /* |
2442 | * Must be called with the queue_lock held. |
2443 | */ |
2444 | static int cfqq_process_refs(struct cfq_queue *cfqq) |
2445 | { |
2446 | int process_refs, io_refs; |
2447 | |
2448 | io_refs = cfqq->allocated[READ] + cfqq->allocated[WRITE]; |
2449 | process_refs = cfqq->ref - io_refs; |
2450 | BUG_ON(process_refs < 0); |
2451 | return process_refs; |
2452 | } |
2453 | |
2454 | static void cfq_setup_merge(struct cfq_queue *cfqq, struct cfq_queue *new_cfqq) |
2455 | { |
2456 | int process_refs, new_process_refs; |
2457 | struct cfq_queue *__cfqq; |
2458 | |
2459 | /* |
2460 | * If there are no process references on the new_cfqq, then it is |
2461 | * unsafe to follow the ->new_cfqq chain as other cfqq's in the |
2462 | * chain may have dropped their last reference (not just their |
2463 | * last process reference). |
2464 | */ |
2465 | if (!cfqq_process_refs(new_cfqq)) |
2466 | return; |
2467 | |
2468 | /* Avoid a circular list and skip interim queue merges */ |
2469 | while ((__cfqq = new_cfqq->new_cfqq)) { |
2470 | if (__cfqq == cfqq) |
2471 | return; |
2472 | new_cfqq = __cfqq; |
2473 | } |
2474 | |
2475 | process_refs = cfqq_process_refs(cfqq); |
2476 | new_process_refs = cfqq_process_refs(new_cfqq); |
2477 | /* |
2478 | * If the process for the cfqq has gone away, there is no |
2479 | * sense in merging the queues. |
2480 | */ |
2481 | if (process_refs == 0 || new_process_refs == 0) |
2482 | return; |
2483 | |
2484 | /* |
2485 | * Merge in the direction of the lesser amount of work. |
2486 | */ |
2487 | if (new_process_refs >= process_refs) { |
2488 | cfqq->new_cfqq = new_cfqq; |
2489 | new_cfqq->ref += process_refs; |
2490 | } else { |
2491 | new_cfqq->new_cfqq = cfqq; |
2492 | cfqq->ref += new_process_refs; |
2493 | } |
2494 | } |
2495 | |
2496 | static enum wl_type_t cfq_choose_wl(struct cfq_data *cfqd, |
2497 | struct cfq_group *cfqg, enum wl_prio_t prio) |
2498 | { |
2499 | struct cfq_queue *queue; |
2500 | int i; |
2501 | bool key_valid = false; |
2502 | unsigned long lowest_key = 0; |
2503 | enum wl_type_t cur_best = SYNC_NOIDLE_WORKLOAD; |
2504 | |
2505 | for (i = 0; i <= SYNC_WORKLOAD; ++i) { |
2506 | /* select the one with lowest rb_key */ |
2507 | queue = cfq_rb_first(service_tree_for(cfqg, prio, i)); |
2508 | if (queue && |
2509 | (!key_valid || time_before(queue->rb_key, lowest_key))) { |
2510 | lowest_key = queue->rb_key; |
2511 | cur_best = i; |
2512 | key_valid = true; |
2513 | } |
2514 | } |
2515 | |
2516 | return cur_best; |
2517 | } |
2518 | |
2519 | static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg) |
2520 | { |
2521 | unsigned slice; |
2522 | unsigned count; |
2523 | struct cfq_rb_root *st; |
2524 | unsigned group_slice; |
2525 | enum wl_prio_t original_prio = cfqd->serving_prio; |
2526 | |
2527 | /* Choose next priority. RT > BE > IDLE */ |
2528 | if (cfq_group_busy_queues_wl(RT_WORKLOAD, cfqd, cfqg)) |
2529 | cfqd->serving_prio = RT_WORKLOAD; |
2530 | else if (cfq_group_busy_queues_wl(BE_WORKLOAD, cfqd, cfqg)) |
2531 | cfqd->serving_prio = BE_WORKLOAD; |
2532 | else { |
2533 | cfqd->serving_prio = IDLE_WORKLOAD; |
2534 | cfqd->workload_expires = jiffies + 1; |
2535 | return; |
2536 | } |
2537 | |
2538 | if (original_prio != cfqd->serving_prio) |
2539 | goto new_workload; |
2540 | |
2541 | /* |
2542 | * For RT and BE, we have to choose also the type |
2543 | * (SYNC, SYNC_NOIDLE, ASYNC), and to compute a workload |
2544 | * expiration time |
2545 | */ |
2546 | st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type); |
2547 | count = st->count; |
2548 | |
2549 | /* |
2550 | * check workload expiration, and that we still have other queues ready |
2551 | */ |
2552 | if (count && !time_after(jiffies, cfqd->workload_expires)) |
2553 | return; |
2554 | |
2555 | new_workload: |
2556 | /* otherwise select new workload type */ |
2557 | cfqd->serving_type = |
2558 | cfq_choose_wl(cfqd, cfqg, cfqd->serving_prio); |
2559 | st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type); |
2560 | count = st->count; |
2561 | |
2562 | /* |
2563 | * the workload slice is computed as a fraction of target latency |
2564 | * proportional to the number of queues in that workload, over |
2565 | * all the queues in the same priority class |
2566 | */ |
2567 | group_slice = cfq_group_slice(cfqd, cfqg); |
2568 | |
2569 | slice = group_slice * count / |
2570 | max_t(unsigned, cfqg->busy_queues_avg[cfqd->serving_prio], |
2571 | cfq_group_busy_queues_wl(cfqd->serving_prio, cfqd, cfqg)); |
2572 | |
2573 | if (cfqd->serving_type == ASYNC_WORKLOAD) { |
2574 | unsigned int tmp; |
2575 | |
2576 | /* |
2577 | * Async queues are currently system wide. Just taking |
2578 | * proportion of queues with-in same group will lead to higher |
2579 | * async ratio system wide as generally root group is going |
2580 | * to have higher weight. A more accurate thing would be to |
2581 | * calculate system wide asnc/sync ratio. |
2582 | */ |
2583 | tmp = cfqd->cfq_target_latency * |
2584 | cfqg_busy_async_queues(cfqd, cfqg); |
2585 | tmp = tmp/cfqd->busy_queues; |
2586 | slice = min_t(unsigned, slice, tmp); |
2587 | |
2588 | /* async workload slice is scaled down according to |
2589 | * the sync/async slice ratio. */ |
2590 | slice = slice * cfqd->cfq_slice[0] / cfqd->cfq_slice[1]; |
2591 | } else |
2592 | /* sync workload slice is at least 2 * cfq_slice_idle */ |
2593 | slice = max(slice, 2 * cfqd->cfq_slice_idle); |
2594 | |
2595 | slice = max_t(unsigned, slice, CFQ_MIN_TT); |
2596 | cfq_log(cfqd, "workload slice:%d", slice); |
2597 | cfqd->workload_expires = jiffies + slice; |
2598 | } |
2599 | |
2600 | static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd) |
2601 | { |
2602 | struct cfq_rb_root *st = &cfqd->grp_service_tree; |
2603 | struct cfq_group *cfqg; |
2604 | |
2605 | if (RB_EMPTY_ROOT(&st->rb)) |
2606 | return NULL; |
2607 | cfqg = cfq_rb_first_group(st); |
2608 | update_min_vdisktime(st); |
2609 | return cfqg; |
2610 | } |
2611 | |
2612 | static void cfq_choose_cfqg(struct cfq_data *cfqd) |
2613 | { |
2614 | struct cfq_group *cfqg = cfq_get_next_cfqg(cfqd); |
2615 | |
2616 | cfqd->serving_group = cfqg; |
2617 | |
2618 | /* Restore the workload type data */ |
2619 | if (cfqg->saved_workload_slice) { |
2620 | cfqd->workload_expires = jiffies + cfqg->saved_workload_slice; |
2621 | cfqd->serving_type = cfqg->saved_workload; |
2622 | cfqd->serving_prio = cfqg->saved_serving_prio; |
2623 | } else |
2624 | cfqd->workload_expires = jiffies - 1; |
2625 | |
2626 | choose_service_tree(cfqd, cfqg); |
2627 | } |
2628 | |
2629 | /* |
2630 | * Select a queue for service. If we have a current active queue, |
2631 | * check whether to continue servicing it, or retrieve and set a new one. |
2632 | */ |
2633 | static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) |
2634 | { |
2635 | struct cfq_queue *cfqq, *new_cfqq = NULL; |
2636 | |
2637 | cfqq = cfqd->active_queue; |
2638 | if (!cfqq) |
2639 | goto new_queue; |
2640 | |
2641 | if (!cfqd->rq_queued) |
2642 | return NULL; |
2643 | |
2644 | /* |
2645 | * We were waiting for group to get backlogged. Expire the queue |
2646 | */ |
2647 | if (cfq_cfqq_wait_busy(cfqq) && !RB_EMPTY_ROOT(&cfqq->sort_list)) |
2648 | goto expire; |
2649 | |
2650 | /* |
2651 | * The active queue has run out of time, expire it and select new. |
2652 | */ |
2653 | if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq)) { |
2654 | /* |
2655 | * If slice had not expired at the completion of last request |
2656 | * we might not have turned on wait_busy flag. Don't expire |
2657 | * the queue yet. Allow the group to get backlogged. |
2658 | * |
2659 | * The very fact that we have used the slice, that means we |
2660 | * have been idling all along on this queue and it should be |
2661 | * ok to wait for this request to complete. |
2662 | */ |
2663 | if (cfqq->cfqg->nr_cfqq == 1 && RB_EMPTY_ROOT(&cfqq->sort_list) |
2664 | && cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) { |
2665 | cfqq = NULL; |
2666 | goto keep_queue; |
2667 | } else |
2668 | goto check_group_idle; |
2669 | } |
2670 | |
2671 | /* |
2672 | * The active queue has requests and isn't expired, allow it to |
2673 | * dispatch. |
2674 | */ |
2675 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
2676 | goto keep_queue; |
2677 | |
2678 | /* |
2679 | * If another queue has a request waiting within our mean seek |
2680 | * distance, let it run. The expire code will check for close |
2681 | * cooperators and put the close queue at the front of the service |
2682 | * tree. If possible, merge the expiring queue with the new cfqq. |
2683 | */ |
2684 | new_cfqq = cfq_close_cooperator(cfqd, cfqq); |
2685 | if (new_cfqq) { |
2686 | if (!cfqq->new_cfqq) |
2687 | cfq_setup_merge(cfqq, new_cfqq); |
2688 | goto expire; |
2689 | } |
2690 | |
2691 | /* |
2692 | * No requests pending. If the active queue still has requests in |
2693 | * flight or is idling for a new request, allow either of these |
2694 | * conditions to happen (or time out) before selecting a new queue. |
2695 | */ |
2696 | if (timer_pending(&cfqd->idle_slice_timer)) { |
2697 | cfqq = NULL; |
2698 | goto keep_queue; |
2699 | } |
2700 | |
2701 | /* |
2702 | * This is a deep seek queue, but the device is much faster than |
2703 | * the queue can deliver, don't idle |
2704 | **/ |
2705 | if (CFQQ_SEEKY(cfqq) && cfq_cfqq_idle_window(cfqq) && |
2706 | (cfq_cfqq_slice_new(cfqq) || |
2707 | (cfqq->slice_end - jiffies > jiffies - cfqq->slice_start))) { |
2708 | cfq_clear_cfqq_deep(cfqq); |
2709 | cfq_clear_cfqq_idle_window(cfqq); |
2710 | } |
2711 | |
2712 | if (cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) { |
2713 | cfqq = NULL; |
2714 | goto keep_queue; |
2715 | } |
2716 | |
2717 | /* |
2718 | * If group idle is enabled and there are requests dispatched from |
2719 | * this group, wait for requests to complete. |
2720 | */ |
2721 | check_group_idle: |
2722 | if (cfqd->cfq_group_idle && cfqq->cfqg->nr_cfqq == 1 && |
2723 | cfqq->cfqg->dispatched && |
2724 | !cfq_io_thinktime_big(cfqd, &cfqq->cfqg->ttime, true)) { |
2725 | cfqq = NULL; |
2726 | goto keep_queue; |
2727 | } |
2728 | |
2729 | expire: |
2730 | cfq_slice_expired(cfqd, 0); |
2731 | new_queue: |
2732 | /* |
2733 | * Current queue expired. Check if we have to switch to a new |
2734 | * service tree |
2735 | */ |
2736 | if (!new_cfqq) |
2737 | cfq_choose_cfqg(cfqd); |
2738 | |
2739 | cfqq = cfq_set_active_queue(cfqd, new_cfqq); |
2740 | keep_queue: |
2741 | return cfqq; |
2742 | } |
2743 | |
2744 | static int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq) |
2745 | { |
2746 | int dispatched = 0; |
2747 | |
2748 | while (cfqq->next_rq) { |
2749 | cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq); |
2750 | dispatched++; |
2751 | } |
2752 | |
2753 | BUG_ON(!list_empty(&cfqq->fifo)); |
2754 | |
2755 | /* By default cfqq is not expired if it is empty. Do it explicitly */ |
2756 | __cfq_slice_expired(cfqq->cfqd, cfqq, 0); |
2757 | return dispatched; |
2758 | } |
2759 | |
2760 | /* |
2761 | * Drain our current requests. Used for barriers and when switching |
2762 | * io schedulers on-the-fly. |
2763 | */ |
2764 | static int cfq_forced_dispatch(struct cfq_data *cfqd) |
2765 | { |
2766 | struct cfq_queue *cfqq; |
2767 | int dispatched = 0; |
2768 | |
2769 | /* Expire the timeslice of the current active queue first */ |
2770 | cfq_slice_expired(cfqd, 0); |
2771 | while ((cfqq = cfq_get_next_queue_forced(cfqd)) != NULL) { |
2772 | __cfq_set_active_queue(cfqd, cfqq); |
2773 | dispatched += __cfq_forced_dispatch_cfqq(cfqq); |
2774 | } |
2775 | |
2776 | BUG_ON(cfqd->busy_queues); |
2777 | |
2778 | cfq_log(cfqd, "forced_dispatch=%d", dispatched); |
2779 | return dispatched; |
2780 | } |
2781 | |
2782 | static inline bool cfq_slice_used_soon(struct cfq_data *cfqd, |
2783 | struct cfq_queue *cfqq) |
2784 | { |
2785 | /* the queue hasn't finished any request, can't estimate */ |
2786 | if (cfq_cfqq_slice_new(cfqq)) |
2787 | return true; |
2788 | if (time_after(jiffies + cfqd->cfq_slice_idle * cfqq->dispatched, |
2789 | cfqq->slice_end)) |
2790 | return true; |
2791 | |
2792 | return false; |
2793 | } |
2794 | |
2795 | static bool cfq_may_dispatch(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
2796 | { |
2797 | unsigned int max_dispatch; |
2798 | |
2799 | /* |
2800 | * Drain async requests before we start sync IO |
2801 | */ |
2802 | if (cfq_should_idle(cfqd, cfqq) && cfqd->rq_in_flight[BLK_RW_ASYNC]) |
2803 | return false; |
2804 | |
2805 | /* |
2806 | * If this is an async queue and we have sync IO in flight, let it wait |
2807 | */ |
2808 | if (cfqd->rq_in_flight[BLK_RW_SYNC] && !cfq_cfqq_sync(cfqq)) |
2809 | return false; |
2810 | |
2811 | max_dispatch = max_t(unsigned int, cfqd->cfq_quantum / 2, 1); |
2812 | if (cfq_class_idle(cfqq)) |
2813 | max_dispatch = 1; |
2814 | |
2815 | /* |
2816 | * Does this cfqq already have too much IO in flight? |
2817 | */ |
2818 | if (cfqq->dispatched >= max_dispatch) { |
2819 | bool promote_sync = false; |
2820 | /* |
2821 | * idle queue must always only have a single IO in flight |
2822 | */ |
2823 | if (cfq_class_idle(cfqq)) |
2824 | return false; |
2825 | |
2826 | /* |
2827 | * If there is only one sync queue |
2828 | * we can ignore async queue here and give the sync |
2829 | * queue no dispatch limit. The reason is a sync queue can |
2830 | * preempt async queue, limiting the sync queue doesn't make |
2831 | * sense. This is useful for aiostress test. |
2832 | */ |
2833 | if (cfq_cfqq_sync(cfqq) && cfqd->busy_sync_queues == 1) |
2834 | promote_sync = true; |
2835 | |
2836 | /* |
2837 | * We have other queues, don't allow more IO from this one |
2838 | */ |
2839 | if (cfqd->busy_queues > 1 && cfq_slice_used_soon(cfqd, cfqq) && |
2840 | !promote_sync) |
2841 | return false; |
2842 | |
2843 | /* |
2844 | * Sole queue user, no limit |
2845 | */ |
2846 | if (cfqd->busy_queues == 1 || promote_sync) |
2847 | max_dispatch = -1; |
2848 | else |
2849 | /* |
2850 | * Normally we start throttling cfqq when cfq_quantum/2 |
2851 | * requests have been dispatched. But we can drive |
2852 | * deeper queue depths at the beginning of slice |
2853 | * subjected to upper limit of cfq_quantum. |
2854 | * */ |
2855 | max_dispatch = cfqd->cfq_quantum; |
2856 | } |
2857 | |
2858 | /* |
2859 | * Async queues must wait a bit before being allowed dispatch. |
2860 | * We also ramp up the dispatch depth gradually for async IO, |
2861 | * based on the last sync IO we serviced |
2862 | */ |
2863 | if (!cfq_cfqq_sync(cfqq) && cfqd->cfq_latency) { |
2864 | unsigned long last_sync = jiffies - cfqd->last_delayed_sync; |
2865 | unsigned int depth; |
2866 | |
2867 | depth = last_sync / cfqd->cfq_slice[1]; |
2868 | if (!depth && !cfqq->dispatched) |
2869 | depth = 1; |
2870 | if (depth < max_dispatch) |
2871 | max_dispatch = depth; |
2872 | } |
2873 | |
2874 | /* |
2875 | * If we're below the current max, allow a dispatch |
2876 | */ |
2877 | return cfqq->dispatched < max_dispatch; |
2878 | } |
2879 | |
2880 | /* |
2881 | * Dispatch a request from cfqq, moving them to the request queue |
2882 | * dispatch list. |
2883 | */ |
2884 | static bool cfq_dispatch_request(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
2885 | { |
2886 | struct request *rq; |
2887 | |
2888 | BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list)); |
2889 | |
2890 | if (!cfq_may_dispatch(cfqd, cfqq)) |
2891 | return false; |
2892 | |
2893 | /* |
2894 | * follow expired path, else get first next available |
2895 | */ |
2896 | rq = cfq_check_fifo(cfqq); |
2897 | if (!rq) |
2898 | rq = cfqq->next_rq; |
2899 | |
2900 | /* |
2901 | * insert request into driver dispatch list |
2902 | */ |
2903 | cfq_dispatch_insert(cfqd->queue, rq); |
2904 | |
2905 | if (!cfqd->active_cic) { |
2906 | struct cfq_io_cq *cic = RQ_CIC(rq); |
2907 | |
2908 | atomic_long_inc(&cic->icq.ioc->refcount); |
2909 | cfqd->active_cic = cic; |
2910 | } |
2911 | |
2912 | return true; |
2913 | } |
2914 | |
2915 | /* |
2916 | * Find the cfqq that we need to service and move a request from that to the |
2917 | * dispatch list |
2918 | */ |
2919 | static int cfq_dispatch_requests(struct request_queue *q, int force) |
2920 | { |
2921 | struct cfq_data *cfqd = q->elevator->elevator_data; |
2922 | struct cfq_queue *cfqq; |
2923 | |
2924 | if (!cfqd->busy_queues) |
2925 | return 0; |
2926 | |
2927 | if (unlikely(force)) |
2928 | return cfq_forced_dispatch(cfqd); |
2929 | |
2930 | cfqq = cfq_select_queue(cfqd); |
2931 | if (!cfqq) |
2932 | return 0; |
2933 | |
2934 | /* |
2935 | * Dispatch a request from this cfqq, if it is allowed |
2936 | */ |
2937 | if (!cfq_dispatch_request(cfqd, cfqq)) |
2938 | return 0; |
2939 | |
2940 | cfqq->slice_dispatch++; |
2941 | cfq_clear_cfqq_must_dispatch(cfqq); |
2942 | |
2943 | /* |
2944 | * expire an async queue immediately if it has used up its slice. idle |
2945 | * queue always expire after 1 dispatch round. |
2946 | */ |
2947 | if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) && |
2948 | cfqq->slice_dispatch >= cfq_prio_to_maxrq(cfqd, cfqq)) || |
2949 | cfq_class_idle(cfqq))) { |
2950 | cfqq->slice_end = jiffies + 1; |
2951 | cfq_slice_expired(cfqd, 0); |
2952 | } |
2953 | |
2954 | cfq_log_cfqq(cfqd, cfqq, "dispatched a request"); |
2955 | return 1; |
2956 | } |
2957 | |
2958 | /* |
2959 | * task holds one reference to the queue, dropped when task exits. each rq |
2960 | * in-flight on this queue also holds a reference, dropped when rq is freed. |
2961 | * |
2962 | * Each cfq queue took a reference on the parent group. Drop it now. |
2963 | * queue lock must be held here. |
2964 | */ |
2965 | static void cfq_put_queue(struct cfq_queue *cfqq) |
2966 | { |
2967 | struct cfq_data *cfqd = cfqq->cfqd; |
2968 | struct cfq_group *cfqg; |
2969 | |
2970 | BUG_ON(cfqq->ref <= 0); |
2971 | |
2972 | cfqq->ref--; |
2973 | if (cfqq->ref) |
2974 | return; |
2975 | |
2976 | cfq_log_cfqq(cfqd, cfqq, "put_queue"); |
2977 | BUG_ON(rb_first(&cfqq->sort_list)); |
2978 | BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]); |
2979 | cfqg = cfqq->cfqg; |
2980 | |
2981 | if (unlikely(cfqd->active_queue == cfqq)) { |
2982 | __cfq_slice_expired(cfqd, cfqq, 0); |
2983 | cfq_schedule_dispatch(cfqd); |
2984 | } |
2985 | |
2986 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
2987 | kmem_cache_free(cfq_pool, cfqq); |
2988 | cfqg_put(cfqg); |
2989 | } |
2990 | |
2991 | static void cfq_put_cooperator(struct cfq_queue *cfqq) |
2992 | { |
2993 | struct cfq_queue *__cfqq, *next; |
2994 | |
2995 | /* |
2996 | * If this queue was scheduled to merge with another queue, be |
2997 | * sure to drop the reference taken on that queue (and others in |
2998 | * the merge chain). See cfq_setup_merge and cfq_merge_cfqqs. |
2999 | */ |
3000 | __cfqq = cfqq->new_cfqq; |
3001 | while (__cfqq) { |
3002 | if (__cfqq == cfqq) { |
3003 | WARN(1, "cfqq->new_cfqq loop detected\n"); |
3004 | break; |
3005 | } |
3006 | next = __cfqq->new_cfqq; |
3007 | cfq_put_queue(__cfqq); |
3008 | __cfqq = next; |
3009 | } |
3010 | } |
3011 | |
3012 | static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
3013 | { |
3014 | if (unlikely(cfqq == cfqd->active_queue)) { |
3015 | __cfq_slice_expired(cfqd, cfqq, 0); |
3016 | cfq_schedule_dispatch(cfqd); |
3017 | } |
3018 | |
3019 | cfq_put_cooperator(cfqq); |
3020 | |
3021 | cfq_put_queue(cfqq); |
3022 | } |
3023 | |
3024 | static void cfq_init_icq(struct io_cq *icq) |
3025 | { |
3026 | struct cfq_io_cq *cic = icq_to_cic(icq); |
3027 | |
3028 | cic->ttime.last_end_request = jiffies; |
3029 | } |
3030 | |
3031 | static void cfq_exit_icq(struct io_cq *icq) |
3032 | { |
3033 | struct cfq_io_cq *cic = icq_to_cic(icq); |
3034 | struct cfq_data *cfqd = cic_to_cfqd(cic); |
3035 | |
3036 | if (cic->cfqq[BLK_RW_ASYNC]) { |
3037 | cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_ASYNC]); |
3038 | cic->cfqq[BLK_RW_ASYNC] = NULL; |
3039 | } |
3040 | |
3041 | if (cic->cfqq[BLK_RW_SYNC]) { |
3042 | cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_SYNC]); |
3043 | cic->cfqq[BLK_RW_SYNC] = NULL; |
3044 | } |
3045 | } |
3046 | |
3047 | static void cfq_init_prio_data(struct cfq_queue *cfqq, struct cfq_io_cq *cic) |
3048 | { |
3049 | struct task_struct *tsk = current; |
3050 | int ioprio_class; |
3051 | |
3052 | if (!cfq_cfqq_prio_changed(cfqq)) |
3053 | return; |
3054 | |
3055 | ioprio_class = IOPRIO_PRIO_CLASS(cic->ioprio); |
3056 | switch (ioprio_class) { |
3057 | default: |
3058 | printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class); |
3059 | case IOPRIO_CLASS_NONE: |
3060 | /* |
3061 | * no prio set, inherit CPU scheduling settings |
3062 | */ |
3063 | cfqq->ioprio = task_nice_ioprio(tsk); |
3064 | cfqq->ioprio_class = task_nice_ioclass(tsk); |
3065 | break; |
3066 | case IOPRIO_CLASS_RT: |
3067 | cfqq->ioprio = IOPRIO_PRIO_DATA(cic->ioprio); |
3068 | cfqq->ioprio_class = IOPRIO_CLASS_RT; |
3069 | break; |
3070 | case IOPRIO_CLASS_BE: |
3071 | cfqq->ioprio = IOPRIO_PRIO_DATA(cic->ioprio); |
3072 | cfqq->ioprio_class = IOPRIO_CLASS_BE; |
3073 | break; |
3074 | case IOPRIO_CLASS_IDLE: |
3075 | cfqq->ioprio_class = IOPRIO_CLASS_IDLE; |
3076 | cfqq->ioprio = 7; |
3077 | cfq_clear_cfqq_idle_window(cfqq); |
3078 | break; |
3079 | } |
3080 | |
3081 | /* |
3082 | * keep track of original prio settings in case we have to temporarily |
3083 | * elevate the priority of this queue |
3084 | */ |
3085 | cfqq->org_ioprio = cfqq->ioprio; |
3086 | cfq_clear_cfqq_prio_changed(cfqq); |
3087 | } |
3088 | |
3089 | static void check_ioprio_changed(struct cfq_io_cq *cic, struct bio *bio) |
3090 | { |
3091 | int ioprio = cic->icq.ioc->ioprio; |
3092 | struct cfq_data *cfqd = cic_to_cfqd(cic); |
3093 | struct cfq_queue *cfqq; |
3094 | |
3095 | /* |
3096 | * Check whether ioprio has changed. The condition may trigger |
3097 | * spuriously on a newly created cic but there's no harm. |
3098 | */ |
3099 | if (unlikely(!cfqd) || likely(cic->ioprio == ioprio)) |
3100 | return; |
3101 | |
3102 | cfqq = cic->cfqq[BLK_RW_ASYNC]; |
3103 | if (cfqq) { |
3104 | struct cfq_queue *new_cfqq; |
3105 | new_cfqq = cfq_get_queue(cfqd, BLK_RW_ASYNC, cic, bio, |
3106 | GFP_ATOMIC); |
3107 | if (new_cfqq) { |
3108 | cic->cfqq[BLK_RW_ASYNC] = new_cfqq; |
3109 | cfq_put_queue(cfqq); |
3110 | } |
3111 | } |
3112 | |
3113 | cfqq = cic->cfqq[BLK_RW_SYNC]; |
3114 | if (cfqq) |
3115 | cfq_mark_cfqq_prio_changed(cfqq); |
3116 | |
3117 | cic->ioprio = ioprio; |
3118 | } |
3119 | |
3120 | static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
3121 | pid_t pid, bool is_sync) |
3122 | { |
3123 | RB_CLEAR_NODE(&cfqq->rb_node); |
3124 | RB_CLEAR_NODE(&cfqq->p_node); |
3125 | INIT_LIST_HEAD(&cfqq->fifo); |
3126 | |
3127 | cfqq->ref = 0; |
3128 | cfqq->cfqd = cfqd; |
3129 | |
3130 | cfq_mark_cfqq_prio_changed(cfqq); |
3131 | |
3132 | if (is_sync) { |
3133 | if (!cfq_class_idle(cfqq)) |
3134 | cfq_mark_cfqq_idle_window(cfqq); |
3135 | cfq_mark_cfqq_sync(cfqq); |
3136 | } |
3137 | cfqq->pid = pid; |
3138 | } |
3139 | |
3140 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
3141 | static void check_blkcg_changed(struct cfq_io_cq *cic, struct bio *bio) |
3142 | { |
3143 | struct cfq_data *cfqd = cic_to_cfqd(cic); |
3144 | struct cfq_queue *sync_cfqq; |
3145 | uint64_t id; |
3146 | |
3147 | rcu_read_lock(); |
3148 | id = bio_blkcg(bio)->id; |
3149 | rcu_read_unlock(); |
3150 | |
3151 | /* |
3152 | * Check whether blkcg has changed. The condition may trigger |
3153 | * spuriously on a newly created cic but there's no harm. |
3154 | */ |
3155 | if (unlikely(!cfqd) || likely(cic->blkcg_id == id)) |
3156 | return; |
3157 | |
3158 | sync_cfqq = cic_to_cfqq(cic, 1); |
3159 | if (sync_cfqq) { |
3160 | /* |
3161 | * Drop reference to sync queue. A new sync queue will be |
3162 | * assigned in new group upon arrival of a fresh request. |
3163 | */ |
3164 | cfq_log_cfqq(cfqd, sync_cfqq, "changed cgroup"); |
3165 | cic_set_cfqq(cic, NULL, 1); |
3166 | cfq_put_queue(sync_cfqq); |
3167 | } |
3168 | |
3169 | cic->blkcg_id = id; |
3170 | } |
3171 | #else |
3172 | static inline void check_blkcg_changed(struct cfq_io_cq *cic, struct bio *bio) { } |
3173 | #endif /* CONFIG_CFQ_GROUP_IOSCHED */ |
3174 | |
3175 | static struct cfq_queue * |
3176 | cfq_find_alloc_queue(struct cfq_data *cfqd, bool is_sync, struct cfq_io_cq *cic, |
3177 | struct bio *bio, gfp_t gfp_mask) |
3178 | { |
3179 | struct blkcg *blkcg; |
3180 | struct cfq_queue *cfqq, *new_cfqq = NULL; |
3181 | struct cfq_group *cfqg; |
3182 | |
3183 | retry: |
3184 | rcu_read_lock(); |
3185 | |
3186 | blkcg = bio_blkcg(bio); |
3187 | cfqg = cfq_lookup_create_cfqg(cfqd, blkcg); |
3188 | cfqq = cic_to_cfqq(cic, is_sync); |
3189 | |
3190 | /* |
3191 | * Always try a new alloc if we fell back to the OOM cfqq |
3192 | * originally, since it should just be a temporary situation. |
3193 | */ |
3194 | if (!cfqq || cfqq == &cfqd->oom_cfqq) { |
3195 | cfqq = NULL; |
3196 | if (new_cfqq) { |
3197 | cfqq = new_cfqq; |
3198 | new_cfqq = NULL; |
3199 | } else if (gfp_mask & __GFP_WAIT) { |
3200 | rcu_read_unlock(); |
3201 | spin_unlock_irq(cfqd->queue->queue_lock); |
3202 | new_cfqq = kmem_cache_alloc_node(cfq_pool, |
3203 | gfp_mask | __GFP_ZERO, |
3204 | cfqd->queue->node); |
3205 | spin_lock_irq(cfqd->queue->queue_lock); |
3206 | if (new_cfqq) |
3207 | goto retry; |
3208 | } else { |
3209 | cfqq = kmem_cache_alloc_node(cfq_pool, |
3210 | gfp_mask | __GFP_ZERO, |
3211 | cfqd->queue->node); |
3212 | } |
3213 | |
3214 | if (cfqq) { |
3215 | cfq_init_cfqq(cfqd, cfqq, current->pid, is_sync); |
3216 | cfq_init_prio_data(cfqq, cic); |
3217 | cfq_link_cfqq_cfqg(cfqq, cfqg); |
3218 | cfq_log_cfqq(cfqd, cfqq, "alloced"); |
3219 | } else |
3220 | cfqq = &cfqd->oom_cfqq; |
3221 | } |
3222 | |
3223 | if (new_cfqq) |
3224 | kmem_cache_free(cfq_pool, new_cfqq); |
3225 | |
3226 | rcu_read_unlock(); |
3227 | return cfqq; |
3228 | } |
3229 | |
3230 | static struct cfq_queue ** |
3231 | cfq_async_queue_prio(struct cfq_data *cfqd, int ioprio_class, int ioprio) |
3232 | { |
3233 | switch (ioprio_class) { |
3234 | case IOPRIO_CLASS_RT: |
3235 | return &cfqd->async_cfqq[0][ioprio]; |
3236 | case IOPRIO_CLASS_NONE: |
3237 | ioprio = IOPRIO_NORM; |
3238 | /* fall through */ |
3239 | case IOPRIO_CLASS_BE: |
3240 | return &cfqd->async_cfqq[1][ioprio]; |
3241 | case IOPRIO_CLASS_IDLE: |
3242 | return &cfqd->async_idle_cfqq; |
3243 | default: |
3244 | BUG(); |
3245 | } |
3246 | } |
3247 | |
3248 | static struct cfq_queue * |
3249 | cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct cfq_io_cq *cic, |
3250 | struct bio *bio, gfp_t gfp_mask) |
3251 | { |
3252 | const int ioprio_class = IOPRIO_PRIO_CLASS(cic->ioprio); |
3253 | const int ioprio = IOPRIO_PRIO_DATA(cic->ioprio); |
3254 | struct cfq_queue **async_cfqq = NULL; |
3255 | struct cfq_queue *cfqq = NULL; |
3256 | |
3257 | if (!is_sync) { |
3258 | async_cfqq = cfq_async_queue_prio(cfqd, ioprio_class, ioprio); |
3259 | cfqq = *async_cfqq; |
3260 | } |
3261 | |
3262 | if (!cfqq) |
3263 | cfqq = cfq_find_alloc_queue(cfqd, is_sync, cic, bio, gfp_mask); |
3264 | |
3265 | /* |
3266 | * pin the queue now that it's allocated, scheduler exit will prune it |
3267 | */ |
3268 | if (!is_sync && !(*async_cfqq)) { |
3269 | cfqq->ref++; |
3270 | *async_cfqq = cfqq; |
3271 | } |
3272 | |
3273 | cfqq->ref++; |
3274 | return cfqq; |
3275 | } |
3276 | |
3277 | static void |
3278 | __cfq_update_io_thinktime(struct cfq_ttime *ttime, unsigned long slice_idle) |
3279 | { |
3280 | unsigned long elapsed = jiffies - ttime->last_end_request; |
3281 | elapsed = min(elapsed, 2UL * slice_idle); |
3282 | |
3283 | ttime->ttime_samples = (7*ttime->ttime_samples + 256) / 8; |
3284 | ttime->ttime_total = (7*ttime->ttime_total + 256*elapsed) / 8; |
3285 | ttime->ttime_mean = (ttime->ttime_total + 128) / ttime->ttime_samples; |
3286 | } |
3287 | |
3288 | static void |
3289 | cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
3290 | struct cfq_io_cq *cic) |
3291 | { |
3292 | if (cfq_cfqq_sync(cfqq)) { |
3293 | __cfq_update_io_thinktime(&cic->ttime, cfqd->cfq_slice_idle); |
3294 | __cfq_update_io_thinktime(&cfqq->service_tree->ttime, |
3295 | cfqd->cfq_slice_idle); |
3296 | } |
3297 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
3298 | __cfq_update_io_thinktime(&cfqq->cfqg->ttime, cfqd->cfq_group_idle); |
3299 | #endif |
3300 | } |
3301 | |
3302 | static void |
3303 | cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
3304 | struct request *rq) |
3305 | { |
3306 | sector_t sdist = 0; |
3307 | sector_t n_sec = blk_rq_sectors(rq); |
3308 | if (cfqq->last_request_pos) { |
3309 | if (cfqq->last_request_pos < blk_rq_pos(rq)) |
3310 | sdist = blk_rq_pos(rq) - cfqq->last_request_pos; |
3311 | else |
3312 | sdist = cfqq->last_request_pos - blk_rq_pos(rq); |
3313 | } |
3314 | |
3315 | cfqq->seek_history <<= 1; |
3316 | if (blk_queue_nonrot(cfqd->queue)) |
3317 | cfqq->seek_history |= (n_sec < CFQQ_SECT_THR_NONROT); |
3318 | else |
3319 | cfqq->seek_history |= (sdist > CFQQ_SEEK_THR); |
3320 | } |
3321 | |
3322 | /* |
3323 | * Disable idle window if the process thinks too long or seeks so much that |
3324 | * it doesn't matter |
3325 | */ |
3326 | static void |
3327 | cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
3328 | struct cfq_io_cq *cic) |
3329 | { |
3330 | int old_idle, enable_idle; |
3331 | |
3332 | /* |
3333 | * Don't idle for async or idle io prio class |
3334 | */ |
3335 | if (!cfq_cfqq_sync(cfqq) || cfq_class_idle(cfqq)) |
3336 | return; |
3337 | |
3338 | enable_idle = old_idle = cfq_cfqq_idle_window(cfqq); |
3339 | |
3340 | if (cfqq->queued[0] + cfqq->queued[1] >= 4) |
3341 | cfq_mark_cfqq_deep(cfqq); |
3342 | |
3343 | if (cfqq->next_rq && (cfqq->next_rq->cmd_flags & REQ_NOIDLE)) |
3344 | enable_idle = 0; |
3345 | else if (!atomic_read(&cic->icq.ioc->active_ref) || |
3346 | !cfqd->cfq_slice_idle || |
3347 | (!cfq_cfqq_deep(cfqq) && CFQQ_SEEKY(cfqq))) |
3348 | enable_idle = 0; |
3349 | else if (sample_valid(cic->ttime.ttime_samples)) { |
3350 | if (cic->ttime.ttime_mean > cfqd->cfq_slice_idle) |
3351 | enable_idle = 0; |
3352 | else |
3353 | enable_idle = 1; |
3354 | } |
3355 | |
3356 | if (old_idle != enable_idle) { |
3357 | cfq_log_cfqq(cfqd, cfqq, "idle=%d", enable_idle); |
3358 | if (enable_idle) |
3359 | cfq_mark_cfqq_idle_window(cfqq); |
3360 | else |
3361 | cfq_clear_cfqq_idle_window(cfqq); |
3362 | } |
3363 | } |
3364 | |
3365 | /* |
3366 | * Check if new_cfqq should preempt the currently active queue. Return 0 for |
3367 | * no or if we aren't sure, a 1 will cause a preempt. |
3368 | */ |
3369 | static bool |
3370 | cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, |
3371 | struct request *rq) |
3372 | { |
3373 | struct cfq_queue *cfqq; |
3374 | |
3375 | cfqq = cfqd->active_queue; |
3376 | if (!cfqq) |
3377 | return false; |
3378 | |
3379 | if (cfq_class_idle(new_cfqq)) |
3380 | return false; |
3381 | |
3382 | if (cfq_class_idle(cfqq)) |
3383 | return true; |
3384 | |
3385 | /* |
3386 | * Don't allow a non-RT request to preempt an ongoing RT cfqq timeslice. |
3387 | */ |
3388 | if (cfq_class_rt(cfqq) && !cfq_class_rt(new_cfqq)) |
3389 | return false; |
3390 | |
3391 | /* |
3392 | * if the new request is sync, but the currently running queue is |
3393 | * not, let the sync request have priority. |
3394 | */ |
3395 | if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq)) |
3396 | return true; |
3397 | |
3398 | if (new_cfqq->cfqg != cfqq->cfqg) |
3399 | return false; |
3400 | |
3401 | if (cfq_slice_used(cfqq)) |
3402 | return true; |
3403 | |
3404 | /* Allow preemption only if we are idling on sync-noidle tree */ |
3405 | if (cfqd->serving_type == SYNC_NOIDLE_WORKLOAD && |
3406 | cfqq_type(new_cfqq) == SYNC_NOIDLE_WORKLOAD && |
3407 | new_cfqq->service_tree->count == 2 && |
3408 | RB_EMPTY_ROOT(&cfqq->sort_list)) |
3409 | return true; |
3410 | |
3411 | /* |
3412 | * So both queues are sync. Let the new request get disk time if |
3413 | * it's a metadata request and the current queue is doing regular IO. |
3414 | */ |
3415 | if ((rq->cmd_flags & REQ_PRIO) && !cfqq->prio_pending) |
3416 | return true; |
3417 | |
3418 | /* |
3419 | * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice. |
3420 | */ |
3421 | if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq)) |
3422 | return true; |
3423 | |
3424 | /* An idle queue should not be idle now for some reason */ |
3425 | if (RB_EMPTY_ROOT(&cfqq->sort_list) && !cfq_should_idle(cfqd, cfqq)) |
3426 | return true; |
3427 | |
3428 | if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq)) |
3429 | return false; |
3430 | |
3431 | /* |
3432 | * if this request is as-good as one we would expect from the |
3433 | * current cfqq, let it preempt |
3434 | */ |
3435 | if (cfq_rq_close(cfqd, cfqq, rq)) |
3436 | return true; |
3437 | |
3438 | return false; |
3439 | } |
3440 | |
3441 | /* |
3442 | * cfqq preempts the active queue. if we allowed preempt with no slice left, |
3443 | * let it have half of its nominal slice. |
3444 | */ |
3445 | static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
3446 | { |
3447 | enum wl_type_t old_type = cfqq_type(cfqd->active_queue); |
3448 | |
3449 | cfq_log_cfqq(cfqd, cfqq, "preempt"); |
3450 | cfq_slice_expired(cfqd, 1); |
3451 | |
3452 | /* |
3453 | * workload type is changed, don't save slice, otherwise preempt |
3454 | * doesn't happen |
3455 | */ |
3456 | if (old_type != cfqq_type(cfqq)) |
3457 | cfqq->cfqg->saved_workload_slice = 0; |
3458 | |
3459 | /* |
3460 | * Put the new queue at the front of the of the current list, |
3461 | * so we know that it will be selected next. |
3462 | */ |
3463 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
3464 | |
3465 | cfq_service_tree_add(cfqd, cfqq, 1); |
3466 | |
3467 | cfqq->slice_end = 0; |
3468 | cfq_mark_cfqq_slice_new(cfqq); |
3469 | } |
3470 | |
3471 | /* |
3472 | * Called when a new fs request (rq) is added (to cfqq). Check if there's |
3473 | * something we should do about it |
3474 | */ |
3475 | static void |
3476 | cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
3477 | struct request *rq) |
3478 | { |
3479 | struct cfq_io_cq *cic = RQ_CIC(rq); |
3480 | |
3481 | cfqd->rq_queued++; |
3482 | if (rq->cmd_flags & REQ_PRIO) |
3483 | cfqq->prio_pending++; |
3484 | |
3485 | cfq_update_io_thinktime(cfqd, cfqq, cic); |
3486 | cfq_update_io_seektime(cfqd, cfqq, rq); |
3487 | cfq_update_idle_window(cfqd, cfqq, cic); |
3488 | |
3489 | cfqq->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq); |
3490 | |
3491 | if (cfqq == cfqd->active_queue) { |
3492 | /* |
3493 | * Remember that we saw a request from this process, but |
3494 | * don't start queuing just yet. Otherwise we risk seeing lots |
3495 | * of tiny requests, because we disrupt the normal plugging |
3496 | * and merging. If the request is already larger than a single |
3497 | * page, let it rip immediately. For that case we assume that |
3498 | * merging is already done. Ditto for a busy system that |
3499 | * has other work pending, don't risk delaying until the |
3500 | * idle timer unplug to continue working. |
3501 | */ |
3502 | if (cfq_cfqq_wait_request(cfqq)) { |
3503 | if (blk_rq_bytes(rq) > PAGE_CACHE_SIZE || |
3504 | cfqd->busy_queues > 1) { |
3505 | cfq_del_timer(cfqd, cfqq); |
3506 | cfq_clear_cfqq_wait_request(cfqq); |
3507 | __blk_run_queue(cfqd->queue); |
3508 | } else { |
3509 | cfqg_stats_update_idle_time(cfqq->cfqg); |
3510 | cfq_mark_cfqq_must_dispatch(cfqq); |
3511 | } |
3512 | } |
3513 | } else if (cfq_should_preempt(cfqd, cfqq, rq)) { |
3514 | /* |
3515 | * not the active queue - expire current slice if it is |
3516 | * idle and has expired it's mean thinktime or this new queue |
3517 | * has some old slice time left and is of higher priority or |
3518 | * this new queue is RT and the current one is BE |
3519 | */ |
3520 | cfq_preempt_queue(cfqd, cfqq); |
3521 | __blk_run_queue(cfqd->queue); |
3522 | } |
3523 | } |
3524 | |
3525 | static void cfq_insert_request(struct request_queue *q, struct request *rq) |
3526 | { |
3527 | struct cfq_data *cfqd = q->elevator->elevator_data; |
3528 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
3529 | |
3530 | cfq_log_cfqq(cfqd, cfqq, "insert_request"); |
3531 | cfq_init_prio_data(cfqq, RQ_CIC(rq)); |
3532 | |
3533 | rq_set_fifo_time(rq, jiffies + cfqd->cfq_fifo_expire[rq_is_sync(rq)]); |
3534 | list_add_tail(&rq->queuelist, &cfqq->fifo); |
3535 | cfq_add_rq_rb(rq); |
3536 | cfqg_stats_update_io_add(RQ_CFQG(rq), cfqd->serving_group, |
3537 | rq->cmd_flags); |
3538 | cfq_rq_enqueued(cfqd, cfqq, rq); |
3539 | } |
3540 | |
3541 | /* |
3542 | * Update hw_tag based on peak queue depth over 50 samples under |
3543 | * sufficient load. |
3544 | */ |
3545 | static void cfq_update_hw_tag(struct cfq_data *cfqd) |
3546 | { |
3547 | struct cfq_queue *cfqq = cfqd->active_queue; |
3548 | |
3549 | if (cfqd->rq_in_driver > cfqd->hw_tag_est_depth) |
3550 | cfqd->hw_tag_est_depth = cfqd->rq_in_driver; |
3551 | |
3552 | if (cfqd->hw_tag == 1) |
3553 | return; |
3554 | |
3555 | if (cfqd->rq_queued <= CFQ_HW_QUEUE_MIN && |
3556 | cfqd->rq_in_driver <= CFQ_HW_QUEUE_MIN) |
3557 | return; |
3558 | |
3559 | /* |
3560 | * If active queue hasn't enough requests and can idle, cfq might not |
3561 | * dispatch sufficient requests to hardware. Don't zero hw_tag in this |
3562 | * case |
3563 | */ |
3564 | if (cfqq && cfq_cfqq_idle_window(cfqq) && |
3565 | cfqq->dispatched + cfqq->queued[0] + cfqq->queued[1] < |
3566 | CFQ_HW_QUEUE_MIN && cfqd->rq_in_driver < CFQ_HW_QUEUE_MIN) |
3567 | return; |
3568 | |
3569 | if (cfqd->hw_tag_samples++ < 50) |
3570 | return; |
3571 | |
3572 | if (cfqd->hw_tag_est_depth >= CFQ_HW_QUEUE_MIN) |
3573 | cfqd->hw_tag = 1; |
3574 | else |
3575 | cfqd->hw_tag = 0; |
3576 | } |
3577 | |
3578 | static bool cfq_should_wait_busy(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
3579 | { |
3580 | struct cfq_io_cq *cic = cfqd->active_cic; |
3581 | |
3582 | /* If the queue already has requests, don't wait */ |
3583 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
3584 | return false; |
3585 | |
3586 | /* If there are other queues in the group, don't wait */ |
3587 | if (cfqq->cfqg->nr_cfqq > 1) |
3588 | return false; |
3589 | |
3590 | /* the only queue in the group, but think time is big */ |
3591 | if (cfq_io_thinktime_big(cfqd, &cfqq->cfqg->ttime, true)) |
3592 | return false; |
3593 | |
3594 | if (cfq_slice_used(cfqq)) |
3595 | return true; |
3596 | |
3597 | /* if slice left is less than think time, wait busy */ |
3598 | if (cic && sample_valid(cic->ttime.ttime_samples) |
3599 | && (cfqq->slice_end - jiffies < cic->ttime.ttime_mean)) |
3600 | return true; |
3601 | |
3602 | /* |
3603 | * If think times is less than a jiffy than ttime_mean=0 and above |
3604 | * will not be true. It might happen that slice has not expired yet |
3605 | * but will expire soon (4-5 ns) during select_queue(). To cover the |
3606 | * case where think time is less than a jiffy, mark the queue wait |
3607 | * busy if only 1 jiffy is left in the slice. |
3608 | */ |
3609 | if (cfqq->slice_end - jiffies == 1) |
3610 | return true; |
3611 | |
3612 | return false; |
3613 | } |
3614 | |
3615 | static void cfq_completed_request(struct request_queue *q, struct request *rq) |
3616 | { |
3617 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
3618 | struct cfq_data *cfqd = cfqq->cfqd; |
3619 | const int sync = rq_is_sync(rq); |
3620 | unsigned long now; |
3621 | |
3622 | now = jiffies; |
3623 | cfq_log_cfqq(cfqd, cfqq, "complete rqnoidle %d", |
3624 | !!(rq->cmd_flags & REQ_NOIDLE)); |
3625 | |
3626 | cfq_update_hw_tag(cfqd); |
3627 | |
3628 | WARN_ON(!cfqd->rq_in_driver); |
3629 | WARN_ON(!cfqq->dispatched); |
3630 | cfqd->rq_in_driver--; |
3631 | cfqq->dispatched--; |
3632 | (RQ_CFQG(rq))->dispatched--; |
3633 | cfqg_stats_update_completion(cfqq->cfqg, rq_start_time_ns(rq), |
3634 | rq_io_start_time_ns(rq), rq->cmd_flags); |
3635 | |
3636 | cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]--; |
3637 | |
3638 | if (sync) { |
3639 | struct cfq_rb_root *service_tree; |
3640 | |
3641 | RQ_CIC(rq)->ttime.last_end_request = now; |
3642 | |
3643 | if (cfq_cfqq_on_rr(cfqq)) |
3644 | service_tree = cfqq->service_tree; |
3645 | else |
3646 | service_tree = service_tree_for(cfqq->cfqg, |
3647 | cfqq_prio(cfqq), cfqq_type(cfqq)); |
3648 | service_tree->ttime.last_end_request = now; |
3649 | if (!time_after(rq->start_time + cfqd->cfq_fifo_expire[1], now)) |
3650 | cfqd->last_delayed_sync = now; |
3651 | } |
3652 | |
3653 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
3654 | cfqq->cfqg->ttime.last_end_request = now; |
3655 | #endif |
3656 | |
3657 | /* |
3658 | * If this is the active queue, check if it needs to be expired, |
3659 | * or if we want to idle in case it has no pending requests. |
3660 | */ |
3661 | if (cfqd->active_queue == cfqq) { |
3662 | const bool cfqq_empty = RB_EMPTY_ROOT(&cfqq->sort_list); |
3663 | |
3664 | if (cfq_cfqq_slice_new(cfqq)) { |
3665 | cfq_set_prio_slice(cfqd, cfqq); |
3666 | cfq_clear_cfqq_slice_new(cfqq); |
3667 | } |
3668 | |
3669 | /* |
3670 | * Should we wait for next request to come in before we expire |
3671 | * the queue. |
3672 | */ |
3673 | if (cfq_should_wait_busy(cfqd, cfqq)) { |
3674 | unsigned long extend_sl = cfqd->cfq_slice_idle; |
3675 | if (!cfqd->cfq_slice_idle) |
3676 | extend_sl = cfqd->cfq_group_idle; |
3677 | cfqq->slice_end = jiffies + extend_sl; |
3678 | cfq_mark_cfqq_wait_busy(cfqq); |
3679 | cfq_log_cfqq(cfqd, cfqq, "will busy wait"); |
3680 | } |
3681 | |
3682 | /* |
3683 | * Idling is not enabled on: |
3684 | * - expired queues |
3685 | * - idle-priority queues |
3686 | * - async queues |
3687 | * - queues with still some requests queued |
3688 | * - when there is a close cooperator |
3689 | */ |
3690 | if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq)) |
3691 | cfq_slice_expired(cfqd, 1); |
3692 | else if (sync && cfqq_empty && |
3693 | !cfq_close_cooperator(cfqd, cfqq)) { |
3694 | cfq_arm_slice_timer(cfqd); |
3695 | } |
3696 | } |
3697 | |
3698 | if (!cfqd->rq_in_driver) |
3699 | cfq_schedule_dispatch(cfqd); |
3700 | } |
3701 | |
3702 | static inline int __cfq_may_queue(struct cfq_queue *cfqq) |
3703 | { |
3704 | if (cfq_cfqq_wait_request(cfqq) && !cfq_cfqq_must_alloc_slice(cfqq)) { |
3705 | cfq_mark_cfqq_must_alloc_slice(cfqq); |
3706 | return ELV_MQUEUE_MUST; |
3707 | } |
3708 | |
3709 | return ELV_MQUEUE_MAY; |
3710 | } |
3711 | |
3712 | static int cfq_may_queue(struct request_queue *q, int rw) |
3713 | { |
3714 | struct cfq_data *cfqd = q->elevator->elevator_data; |
3715 | struct task_struct *tsk = current; |
3716 | struct cfq_io_cq *cic; |
3717 | struct cfq_queue *cfqq; |
3718 | |
3719 | /* |
3720 | * don't force setup of a queue from here, as a call to may_queue |
3721 | * does not necessarily imply that a request actually will be queued. |
3722 | * so just lookup a possibly existing queue, or return 'may queue' |
3723 | * if that fails |
3724 | */ |
3725 | cic = cfq_cic_lookup(cfqd, tsk->io_context); |
3726 | if (!cic) |
3727 | return ELV_MQUEUE_MAY; |
3728 | |
3729 | cfqq = cic_to_cfqq(cic, rw_is_sync(rw)); |
3730 | if (cfqq) { |
3731 | cfq_init_prio_data(cfqq, cic); |
3732 | |
3733 | return __cfq_may_queue(cfqq); |
3734 | } |
3735 | |
3736 | return ELV_MQUEUE_MAY; |
3737 | } |
3738 | |
3739 | /* |
3740 | * queue lock held here |
3741 | */ |
3742 | static void cfq_put_request(struct request *rq) |
3743 | { |
3744 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
3745 | |
3746 | if (cfqq) { |
3747 | const int rw = rq_data_dir(rq); |
3748 | |
3749 | BUG_ON(!cfqq->allocated[rw]); |
3750 | cfqq->allocated[rw]--; |
3751 | |
3752 | /* Put down rq reference on cfqg */ |
3753 | cfqg_put(RQ_CFQG(rq)); |
3754 | rq->elv.priv[0] = NULL; |
3755 | rq->elv.priv[1] = NULL; |
3756 | |
3757 | cfq_put_queue(cfqq); |
3758 | } |
3759 | } |
3760 | |
3761 | static struct cfq_queue * |
3762 | cfq_merge_cfqqs(struct cfq_data *cfqd, struct cfq_io_cq *cic, |
3763 | struct cfq_queue *cfqq) |
3764 | { |
3765 | cfq_log_cfqq(cfqd, cfqq, "merging with queue %p", cfqq->new_cfqq); |
3766 | cic_set_cfqq(cic, cfqq->new_cfqq, 1); |
3767 | cfq_mark_cfqq_coop(cfqq->new_cfqq); |
3768 | cfq_put_queue(cfqq); |
3769 | return cic_to_cfqq(cic, 1); |
3770 | } |
3771 | |
3772 | /* |
3773 | * Returns NULL if a new cfqq should be allocated, or the old cfqq if this |
3774 | * was the last process referring to said cfqq. |
3775 | */ |
3776 | static struct cfq_queue * |
3777 | split_cfqq(struct cfq_io_cq *cic, struct cfq_queue *cfqq) |
3778 | { |
3779 | if (cfqq_process_refs(cfqq) == 1) { |
3780 | cfqq->pid = current->pid; |
3781 | cfq_clear_cfqq_coop(cfqq); |
3782 | cfq_clear_cfqq_split_coop(cfqq); |
3783 | return cfqq; |
3784 | } |
3785 | |
3786 | cic_set_cfqq(cic, NULL, 1); |
3787 | |
3788 | cfq_put_cooperator(cfqq); |
3789 | |
3790 | cfq_put_queue(cfqq); |
3791 | return NULL; |
3792 | } |
3793 | /* |
3794 | * Allocate cfq data structures associated with this request. |
3795 | */ |
3796 | static int |
3797 | cfq_set_request(struct request_queue *q, struct request *rq, struct bio *bio, |
3798 | gfp_t gfp_mask) |
3799 | { |
3800 | struct cfq_data *cfqd = q->elevator->elevator_data; |
3801 | struct cfq_io_cq *cic = icq_to_cic(rq->elv.icq); |
3802 | const int rw = rq_data_dir(rq); |
3803 | const bool is_sync = rq_is_sync(rq); |
3804 | struct cfq_queue *cfqq; |
3805 | |
3806 | might_sleep_if(gfp_mask & __GFP_WAIT); |
3807 | |
3808 | spin_lock_irq(q->queue_lock); |
3809 | |
3810 | check_ioprio_changed(cic, bio); |
3811 | check_blkcg_changed(cic, bio); |
3812 | new_queue: |
3813 | cfqq = cic_to_cfqq(cic, is_sync); |
3814 | if (!cfqq || cfqq == &cfqd->oom_cfqq) { |
3815 | cfqq = cfq_get_queue(cfqd, is_sync, cic, bio, gfp_mask); |
3816 | cic_set_cfqq(cic, cfqq, is_sync); |
3817 | } else { |
3818 | /* |
3819 | * If the queue was seeky for too long, break it apart. |
3820 | */ |
3821 | if (cfq_cfqq_coop(cfqq) && cfq_cfqq_split_coop(cfqq)) { |
3822 | cfq_log_cfqq(cfqd, cfqq, "breaking apart cfqq"); |
3823 | cfqq = split_cfqq(cic, cfqq); |
3824 | if (!cfqq) |
3825 | goto new_queue; |
3826 | } |
3827 | |
3828 | /* |
3829 | * Check to see if this queue is scheduled to merge with |
3830 | * another, closely cooperating queue. The merging of |
3831 | * queues happens here as it must be done in process context. |
3832 | * The reference on new_cfqq was taken in merge_cfqqs. |
3833 | */ |
3834 | if (cfqq->new_cfqq) |
3835 | cfqq = cfq_merge_cfqqs(cfqd, cic, cfqq); |
3836 | } |
3837 | |
3838 | cfqq->allocated[rw]++; |
3839 | |
3840 | cfqq->ref++; |
3841 | cfqg_get(cfqq->cfqg); |
3842 | rq->elv.priv[0] = cfqq; |
3843 | rq->elv.priv[1] = cfqq->cfqg; |
3844 | spin_unlock_irq(q->queue_lock); |
3845 | return 0; |
3846 | } |
3847 | |
3848 | static void cfq_kick_queue(struct work_struct *work) |
3849 | { |
3850 | struct cfq_data *cfqd = |
3851 | container_of(work, struct cfq_data, unplug_work); |
3852 | struct request_queue *q = cfqd->queue; |
3853 | |
3854 | spin_lock_irq(q->queue_lock); |
3855 | __blk_run_queue(cfqd->queue); |
3856 | spin_unlock_irq(q->queue_lock); |
3857 | } |
3858 | |
3859 | /* |
3860 | * Timer running if the active_queue is currently idling inside its time slice |
3861 | */ |
3862 | static void cfq_idle_slice_timer(unsigned long data) |
3863 | { |
3864 | struct cfq_data *cfqd = (struct cfq_data *) data; |
3865 | struct cfq_queue *cfqq; |
3866 | unsigned long flags; |
3867 | int timed_out = 1; |
3868 | |
3869 | cfq_log(cfqd, "idle timer fired"); |
3870 | |
3871 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); |
3872 | |
3873 | cfqq = cfqd->active_queue; |
3874 | if (cfqq) { |
3875 | timed_out = 0; |
3876 | |
3877 | /* |
3878 | * We saw a request before the queue expired, let it through |
3879 | */ |
3880 | if (cfq_cfqq_must_dispatch(cfqq)) |
3881 | goto out_kick; |
3882 | |
3883 | /* |
3884 | * expired |
3885 | */ |
3886 | if (cfq_slice_used(cfqq)) |
3887 | goto expire; |
3888 | |
3889 | /* |
3890 | * only expire and reinvoke request handler, if there are |
3891 | * other queues with pending requests |
3892 | */ |
3893 | if (!cfqd->busy_queues) |
3894 | goto out_cont; |
3895 | |
3896 | /* |
3897 | * not expired and it has a request pending, let it dispatch |
3898 | */ |
3899 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
3900 | goto out_kick; |
3901 | |
3902 | /* |
3903 | * Queue depth flag is reset only when the idle didn't succeed |
3904 | */ |
3905 | cfq_clear_cfqq_deep(cfqq); |
3906 | } |
3907 | expire: |
3908 | cfq_slice_expired(cfqd, timed_out); |
3909 | out_kick: |
3910 | cfq_schedule_dispatch(cfqd); |
3911 | out_cont: |
3912 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); |
3913 | } |
3914 | |
3915 | static void cfq_shutdown_timer_wq(struct cfq_data *cfqd) |
3916 | { |
3917 | del_timer_sync(&cfqd->idle_slice_timer); |
3918 | cancel_work_sync(&cfqd->unplug_work); |
3919 | } |
3920 | |
3921 | static void cfq_put_async_queues(struct cfq_data *cfqd) |
3922 | { |
3923 | int i; |
3924 | |
3925 | for (i = 0; i < IOPRIO_BE_NR; i++) { |
3926 | if (cfqd->async_cfqq[0][i]) |
3927 | cfq_put_queue(cfqd->async_cfqq[0][i]); |
3928 | if (cfqd->async_cfqq[1][i]) |
3929 | cfq_put_queue(cfqd->async_cfqq[1][i]); |
3930 | } |
3931 | |
3932 | if (cfqd->async_idle_cfqq) |
3933 | cfq_put_queue(cfqd->async_idle_cfqq); |
3934 | } |
3935 | |
3936 | static void cfq_exit_queue(struct elevator_queue *e) |
3937 | { |
3938 | struct cfq_data *cfqd = e->elevator_data; |
3939 | struct request_queue *q = cfqd->queue; |
3940 | |
3941 | cfq_shutdown_timer_wq(cfqd); |
3942 | |
3943 | spin_lock_irq(q->queue_lock); |
3944 | |
3945 | if (cfqd->active_queue) |
3946 | __cfq_slice_expired(cfqd, cfqd->active_queue, 0); |
3947 | |
3948 | cfq_put_async_queues(cfqd); |
3949 | |
3950 | spin_unlock_irq(q->queue_lock); |
3951 | |
3952 | cfq_shutdown_timer_wq(cfqd); |
3953 | |
3954 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
3955 | blkcg_deactivate_policy(q, &blkcg_policy_cfq); |
3956 | #else |
3957 | kfree(cfqd->root_group); |
3958 | #endif |
3959 | kfree(cfqd); |
3960 | } |
3961 | |
3962 | static int cfq_init_queue(struct request_queue *q) |
3963 | { |
3964 | struct cfq_data *cfqd; |
3965 | struct blkcg_gq *blkg __maybe_unused; |
3966 | int i, ret; |
3967 | |
3968 | cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL | __GFP_ZERO, q->node); |
3969 | if (!cfqd) |
3970 | return -ENOMEM; |
3971 | |
3972 | cfqd->queue = q; |
3973 | q->elevator->elevator_data = cfqd; |
3974 | |
3975 | /* Init root service tree */ |
3976 | cfqd->grp_service_tree = CFQ_RB_ROOT; |
3977 | |
3978 | /* Init root group and prefer root group over other groups by default */ |
3979 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
3980 | ret = blkcg_activate_policy(q, &blkcg_policy_cfq); |
3981 | if (ret) |
3982 | goto out_free; |
3983 | |
3984 | cfqd->root_group = blkg_to_cfqg(q->root_blkg); |
3985 | #else |
3986 | ret = -ENOMEM; |
3987 | cfqd->root_group = kzalloc_node(sizeof(*cfqd->root_group), |
3988 | GFP_KERNEL, cfqd->queue->node); |
3989 | if (!cfqd->root_group) |
3990 | goto out_free; |
3991 | |
3992 | cfq_init_cfqg_base(cfqd->root_group); |
3993 | #endif |
3994 | cfqd->root_group->weight = 2 * CFQ_WEIGHT_DEFAULT; |
3995 | |
3996 | /* |
3997 | * Not strictly needed (since RB_ROOT just clears the node and we |
3998 | * zeroed cfqd on alloc), but better be safe in case someone decides |
3999 | * to add magic to the rb code |
4000 | */ |
4001 | for (i = 0; i < CFQ_PRIO_LISTS; i++) |
4002 | cfqd->prio_trees[i] = RB_ROOT; |
4003 | |
4004 | /* |
4005 | * Our fallback cfqq if cfq_find_alloc_queue() runs into OOM issues. |
4006 | * Grab a permanent reference to it, so that the normal code flow |
4007 | * will not attempt to free it. oom_cfqq is linked to root_group |
4008 | * but shouldn't hold a reference as it'll never be unlinked. Lose |
4009 | * the reference from linking right away. |
4010 | */ |
4011 | cfq_init_cfqq(cfqd, &cfqd->oom_cfqq, 1, 0); |
4012 | cfqd->oom_cfqq.ref++; |
4013 | |
4014 | spin_lock_irq(q->queue_lock); |
4015 | cfq_link_cfqq_cfqg(&cfqd->oom_cfqq, cfqd->root_group); |
4016 | cfqg_put(cfqd->root_group); |
4017 | spin_unlock_irq(q->queue_lock); |
4018 | |
4019 | init_timer(&cfqd->idle_slice_timer); |
4020 | cfqd->idle_slice_timer.function = cfq_idle_slice_timer; |
4021 | cfqd->idle_slice_timer.data = (unsigned long) cfqd; |
4022 | |
4023 | INIT_WORK(&cfqd->unplug_work, cfq_kick_queue); |
4024 | |
4025 | cfqd->cfq_quantum = cfq_quantum; |
4026 | cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; |
4027 | cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; |
4028 | cfqd->cfq_back_max = cfq_back_max; |
4029 | cfqd->cfq_back_penalty = cfq_back_penalty; |
4030 | cfqd->cfq_slice[0] = cfq_slice_async; |
4031 | cfqd->cfq_slice[1] = cfq_slice_sync; |
4032 | cfqd->cfq_target_latency = cfq_target_latency; |
4033 | cfqd->cfq_slice_async_rq = cfq_slice_async_rq; |
4034 | cfqd->cfq_slice_idle = cfq_slice_idle; |
4035 | cfqd->cfq_group_idle = cfq_group_idle; |
4036 | cfqd->cfq_latency = 1; |
4037 | cfqd->hw_tag = -1; |
4038 | /* |
4039 | * we optimistically start assuming sync ops weren't delayed in last |
4040 | * second, in order to have larger depth for async operations. |
4041 | */ |
4042 | cfqd->last_delayed_sync = jiffies - HZ; |
4043 | return 0; |
4044 | |
4045 | out_free: |
4046 | kfree(cfqd); |
4047 | return ret; |
4048 | } |
4049 | |
4050 | /* |
4051 | * sysfs parts below --> |
4052 | */ |
4053 | static ssize_t |
4054 | cfq_var_show(unsigned int var, char *page) |
4055 | { |
4056 | return sprintf(page, "%d\n", var); |
4057 | } |
4058 | |
4059 | static ssize_t |
4060 | cfq_var_store(unsigned int *var, const char *page, size_t count) |
4061 | { |
4062 | char *p = (char *) page; |
4063 | |
4064 | *var = simple_strtoul(p, &p, 10); |
4065 | return count; |
4066 | } |
4067 | |
4068 | #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ |
4069 | static ssize_t __FUNC(struct elevator_queue *e, char *page) \ |
4070 | { \ |
4071 | struct cfq_data *cfqd = e->elevator_data; \ |
4072 | unsigned int __data = __VAR; \ |
4073 | if (__CONV) \ |
4074 | __data = jiffies_to_msecs(__data); \ |
4075 | return cfq_var_show(__data, (page)); \ |
4076 | } |
4077 | SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); |
4078 | SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1); |
4079 | SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1); |
4080 | SHOW_FUNCTION(cfq_back_seek_max_show, cfqd->cfq_back_max, 0); |
4081 | SHOW_FUNCTION(cfq_back_seek_penalty_show, cfqd->cfq_back_penalty, 0); |
4082 | SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1); |
4083 | SHOW_FUNCTION(cfq_group_idle_show, cfqd->cfq_group_idle, 1); |
4084 | SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1); |
4085 | SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1); |
4086 | SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0); |
4087 | SHOW_FUNCTION(cfq_low_latency_show, cfqd->cfq_latency, 0); |
4088 | SHOW_FUNCTION(cfq_target_latency_show, cfqd->cfq_target_latency, 1); |
4089 | #undef SHOW_FUNCTION |
4090 | |
4091 | #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ |
4092 | static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \ |
4093 | { \ |
4094 | struct cfq_data *cfqd = e->elevator_data; \ |
4095 | unsigned int __data; \ |
4096 | int ret = cfq_var_store(&__data, (page), count); \ |
4097 | if (__data < (MIN)) \ |
4098 | __data = (MIN); \ |
4099 | else if (__data > (MAX)) \ |
4100 | __data = (MAX); \ |
4101 | if (__CONV) \ |
4102 | *(__PTR) = msecs_to_jiffies(__data); \ |
4103 | else \ |
4104 | *(__PTR) = __data; \ |
4105 | return ret; \ |
4106 | } |
4107 | STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); |
4108 | STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, |
4109 | UINT_MAX, 1); |
4110 | STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, |
4111 | UINT_MAX, 1); |
4112 | STORE_FUNCTION(cfq_back_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); |
4113 | STORE_FUNCTION(cfq_back_seek_penalty_store, &cfqd->cfq_back_penalty, 1, |
4114 | UINT_MAX, 0); |
4115 | STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1); |
4116 | STORE_FUNCTION(cfq_group_idle_store, &cfqd->cfq_group_idle, 0, UINT_MAX, 1); |
4117 | STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1); |
4118 | STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1); |
4119 | STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, |
4120 | UINT_MAX, 0); |
4121 | STORE_FUNCTION(cfq_low_latency_store, &cfqd->cfq_latency, 0, 1, 0); |
4122 | STORE_FUNCTION(cfq_target_latency_store, &cfqd->cfq_target_latency, 1, UINT_MAX, 1); |
4123 | #undef STORE_FUNCTION |
4124 | |
4125 | #define CFQ_ATTR(name) \ |
4126 | __ATTR(name, S_IRUGO|S_IWUSR, cfq_##name##_show, cfq_##name##_store) |
4127 | |
4128 | static struct elv_fs_entry cfq_attrs[] = { |
4129 | CFQ_ATTR(quantum), |
4130 | CFQ_ATTR(fifo_expire_sync), |
4131 | CFQ_ATTR(fifo_expire_async), |
4132 | CFQ_ATTR(back_seek_max), |
4133 | CFQ_ATTR(back_seek_penalty), |
4134 | CFQ_ATTR(slice_sync), |
4135 | CFQ_ATTR(slice_async), |
4136 | CFQ_ATTR(slice_async_rq), |
4137 | CFQ_ATTR(slice_idle), |
4138 | CFQ_ATTR(group_idle), |
4139 | CFQ_ATTR(low_latency), |
4140 | CFQ_ATTR(target_latency), |
4141 | __ATTR_NULL |
4142 | }; |
4143 | |
4144 | static struct elevator_type iosched_cfq = { |
4145 | .ops = { |
4146 | .elevator_merge_fn = cfq_merge, |
4147 | .elevator_merged_fn = cfq_merged_request, |
4148 | .elevator_merge_req_fn = cfq_merged_requests, |
4149 | .elevator_allow_merge_fn = cfq_allow_merge, |
4150 | .elevator_bio_merged_fn = cfq_bio_merged, |
4151 | .elevator_dispatch_fn = cfq_dispatch_requests, |
4152 | .elevator_add_req_fn = cfq_insert_request, |
4153 | .elevator_activate_req_fn = cfq_activate_request, |
4154 | .elevator_deactivate_req_fn = cfq_deactivate_request, |
4155 | .elevator_completed_req_fn = cfq_completed_request, |
4156 | .elevator_former_req_fn = elv_rb_former_request, |
4157 | .elevator_latter_req_fn = elv_rb_latter_request, |
4158 | .elevator_init_icq_fn = cfq_init_icq, |
4159 | .elevator_exit_icq_fn = cfq_exit_icq, |
4160 | .elevator_set_req_fn = cfq_set_request, |
4161 | .elevator_put_req_fn = cfq_put_request, |
4162 | .elevator_may_queue_fn = cfq_may_queue, |
4163 | .elevator_init_fn = cfq_init_queue, |
4164 | .elevator_exit_fn = cfq_exit_queue, |
4165 | }, |
4166 | .icq_size = sizeof(struct cfq_io_cq), |
4167 | .icq_align = __alignof__(struct cfq_io_cq), |
4168 | .elevator_attrs = cfq_attrs, |
4169 | .elevator_name = "cfq", |
4170 | .elevator_owner = THIS_MODULE, |
4171 | }; |
4172 | |
4173 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
4174 | static struct blkcg_policy blkcg_policy_cfq = { |
4175 | .pd_size = sizeof(struct cfq_group), |
4176 | .cftypes = cfq_blkcg_files, |
4177 | |
4178 | .pd_init_fn = cfq_pd_init, |
4179 | .pd_reset_stats_fn = cfq_pd_reset_stats, |
4180 | }; |
4181 | #endif |
4182 | |
4183 | static int __init cfq_init(void) |
4184 | { |
4185 | int ret; |
4186 | |
4187 | /* |
4188 | * could be 0 on HZ < 1000 setups |
4189 | */ |
4190 | if (!cfq_slice_async) |
4191 | cfq_slice_async = 1; |
4192 | if (!cfq_slice_idle) |
4193 | cfq_slice_idle = 1; |
4194 | |
4195 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
4196 | if (!cfq_group_idle) |
4197 | cfq_group_idle = 1; |
4198 | |
4199 | ret = blkcg_policy_register(&blkcg_policy_cfq); |
4200 | if (ret) |
4201 | return ret; |
4202 | #else |
4203 | cfq_group_idle = 0; |
4204 | #endif |
4205 | |
4206 | ret = -ENOMEM; |
4207 | cfq_pool = KMEM_CACHE(cfq_queue, 0); |
4208 | if (!cfq_pool) |
4209 | goto err_pol_unreg; |
4210 | |
4211 | ret = elv_register(&iosched_cfq); |
4212 | if (ret) |
4213 | goto err_free_pool; |
4214 | |
4215 | return 0; |
4216 | |
4217 | err_free_pool: |
4218 | kmem_cache_destroy(cfq_pool); |
4219 | err_pol_unreg: |
4220 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
4221 | blkcg_policy_unregister(&blkcg_policy_cfq); |
4222 | #endif |
4223 | return ret; |
4224 | } |
4225 | |
4226 | static void __exit cfq_exit(void) |
4227 | { |
4228 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
4229 | blkcg_policy_unregister(&blkcg_policy_cfq); |
4230 | #endif |
4231 | elv_unregister(&iosched_cfq); |
4232 | kmem_cache_destroy(cfq_pool); |
4233 | } |
4234 | |
4235 | module_init(cfq_init); |
4236 | module_exit(cfq_exit); |
4237 | |
4238 | MODULE_AUTHOR("Jens Axboe"); |
4239 | MODULE_LICENSE("GPL"); |
4240 | MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler"); |
4241 |
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