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Commit | Line | Data |
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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/sched/clock.h> | |
12 | #include <linux/blkdev.h> | |
13 | #include <linux/elevator.h> | |
14 | #include <linux/ktime.h> | |
15 | #include <linux/rbtree.h> | |
16 | #include <linux/ioprio.h> | |
17 | #include <linux/blktrace_api.h> | |
18 | #include <linux/blk-cgroup.h> | |
19 | #include "blk.h" | |
20 | #include "blk-wbt.h" | |
21 | ||
22 | /* | |
23 | * tunables | |
24 | */ | |
25 | /* max queue in one round of service */ | |
26 | static const int cfq_quantum = 8; | |
27 | static const u64 cfq_fifo_expire[2] = { NSEC_PER_SEC / 4, NSEC_PER_SEC / 8 }; | |
28 | /* maximum backwards seek, in KiB */ | |
29 | static const int cfq_back_max = 16 * 1024; | |
30 | /* penalty of a backwards seek */ | |
31 | static const int cfq_back_penalty = 2; | |
32 | static const u64 cfq_slice_sync = NSEC_PER_SEC / 10; | |
33 | static u64 cfq_slice_async = NSEC_PER_SEC / 25; | |
34 | static const int cfq_slice_async_rq = 2; | |
35 | static u64 cfq_slice_idle = NSEC_PER_SEC / 125; | |
36 | static u64 cfq_group_idle = NSEC_PER_SEC / 125; | |
37 | static const u64 cfq_target_latency = (u64)NSEC_PER_SEC * 3/10; /* 300 ms */ | |
38 | static const int cfq_hist_divisor = 4; | |
39 | ||
40 | /* | |
41 | * offset from end of queue service tree for idle class | |
42 | */ | |
43 | #define CFQ_IDLE_DELAY (NSEC_PER_SEC / 5) | |
44 | /* offset from end of group service tree under time slice mode */ | |
45 | #define CFQ_SLICE_MODE_GROUP_DELAY (NSEC_PER_SEC / 5) | |
46 | /* offset from end of group service under IOPS mode */ | |
47 | #define CFQ_IOPS_MODE_GROUP_DELAY (HZ / 5) | |
48 | ||
49 | /* | |
50 | * below this threshold, we consider thinktime immediate | |
51 | */ | |
52 | #define CFQ_MIN_TT (2 * NSEC_PER_SEC / HZ) | |
53 | ||
54 | #define CFQ_SLICE_SCALE (5) | |
55 | #define CFQ_HW_QUEUE_MIN (5) | |
56 | #define CFQ_SERVICE_SHIFT 12 | |
57 | ||
58 | #define CFQQ_SEEK_THR (sector_t)(8 * 100) | |
59 | #define CFQQ_CLOSE_THR (sector_t)(8 * 1024) | |
60 | #define CFQQ_SECT_THR_NONROT (sector_t)(2 * 32) | |
61 | #define CFQQ_SEEKY(cfqq) (hweight32(cfqq->seek_history) > 32/8) | |
62 | ||
63 | #define RQ_CIC(rq) icq_to_cic((rq)->elv.icq) | |
64 | #define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elv.priv[0]) | |
65 | #define RQ_CFQG(rq) (struct cfq_group *) ((rq)->elv.priv[1]) | |
66 | ||
67 | static struct kmem_cache *cfq_pool; | |
68 | ||
69 | #define CFQ_PRIO_LISTS IOPRIO_BE_NR | |
70 | #define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE) | |
71 | #define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT) | |
72 | ||
73 | #define sample_valid(samples) ((samples) > 80) | |
74 | #define rb_entry_cfqg(node) rb_entry((node), struct cfq_group, rb_node) | |
75 | ||
76 | /* blkio-related constants */ | |
77 | #define CFQ_WEIGHT_LEGACY_MIN 10 | |
78 | #define CFQ_WEIGHT_LEGACY_DFL 500 | |
79 | #define CFQ_WEIGHT_LEGACY_MAX 1000 | |
80 | ||
81 | struct cfq_ttime { | |
82 | u64 last_end_request; | |
83 | ||
84 | u64 ttime_total; | |
85 | u64 ttime_mean; | |
86 | unsigned long ttime_samples; | |
87 | }; | |
88 | ||
89 | /* | |
90 | * Most of our rbtree usage is for sorting with min extraction, so | |
91 | * if we cache the leftmost node we don't have to walk down the tree | |
92 | * to find it. Idea borrowed from Ingo Molnars CFS scheduler. We should | |
93 | * move this into the elevator for the rq sorting as well. | |
94 | */ | |
95 | struct cfq_rb_root { | |
96 | struct rb_root_cached rb; | |
97 | struct rb_node *rb_rightmost; | |
98 | unsigned count; | |
99 | u64 min_vdisktime; | |
100 | struct cfq_ttime ttime; | |
101 | }; | |
102 | #define CFQ_RB_ROOT (struct cfq_rb_root) { .rb = RB_ROOT_CACHED, \ | |
103 | .rb_rightmost = NULL, \ | |
104 | .ttime = {.last_end_request = ktime_get_ns(),},} | |
105 | ||
106 | /* | |
107 | * Per process-grouping structure | |
108 | */ | |
109 | struct cfq_queue { | |
110 | /* reference count */ | |
111 | int ref; | |
112 | /* various state flags, see below */ | |
113 | unsigned int flags; | |
114 | /* parent cfq_data */ | |
115 | struct cfq_data *cfqd; | |
116 | /* service_tree member */ | |
117 | struct rb_node rb_node; | |
118 | /* service_tree key */ | |
119 | u64 rb_key; | |
120 | /* prio tree member */ | |
121 | struct rb_node p_node; | |
122 | /* prio tree root we belong to, if any */ | |
123 | struct rb_root *p_root; | |
124 | /* sorted list of pending requests */ | |
125 | struct rb_root sort_list; | |
126 | /* if fifo isn't expired, next request to serve */ | |
127 | struct request *next_rq; | |
128 | /* requests queued in sort_list */ | |
129 | int queued[2]; | |
130 | /* currently allocated requests */ | |
131 | int allocated[2]; | |
132 | /* fifo list of requests in sort_list */ | |
133 | struct list_head fifo; | |
134 | ||
135 | /* time when queue got scheduled in to dispatch first request. */ | |
136 | u64 dispatch_start; | |
137 | u64 allocated_slice; | |
138 | u64 slice_dispatch; | |
139 | /* time when first request from queue completed and slice started. */ | |
140 | u64 slice_start; | |
141 | u64 slice_end; | |
142 | s64 slice_resid; | |
143 | ||
144 | /* pending priority requests */ | |
145 | int prio_pending; | |
146 | /* number of requests that are on the dispatch list or inside driver */ | |
147 | int dispatched; | |
148 | ||
149 | /* io prio of this group */ | |
150 | unsigned short ioprio, org_ioprio; | |
151 | unsigned short ioprio_class, org_ioprio_class; | |
152 | ||
153 | pid_t pid; | |
154 | ||
155 | u32 seek_history; | |
156 | sector_t last_request_pos; | |
157 | ||
158 | struct cfq_rb_root *service_tree; | |
159 | struct cfq_queue *new_cfqq; | |
160 | struct cfq_group *cfqg; | |
161 | /* Number of sectors dispatched from queue in single dispatch round */ | |
162 | unsigned long nr_sectors; | |
163 | }; | |
164 | ||
165 | /* | |
166 | * First index in the service_trees. | |
167 | * IDLE is handled separately, so it has negative index | |
168 | */ | |
169 | enum wl_class_t { | |
170 | BE_WORKLOAD = 0, | |
171 | RT_WORKLOAD = 1, | |
172 | IDLE_WORKLOAD = 2, | |
173 | CFQ_PRIO_NR, | |
174 | }; | |
175 | ||
176 | /* | |
177 | * Second index in the service_trees. | |
178 | */ | |
179 | enum wl_type_t { | |
180 | ASYNC_WORKLOAD = 0, | |
181 | SYNC_NOIDLE_WORKLOAD = 1, | |
182 | SYNC_WORKLOAD = 2 | |
183 | }; | |
184 | ||
185 | struct cfqg_stats { | |
186 | #ifdef CONFIG_CFQ_GROUP_IOSCHED | |
187 | /* number of ios merged */ | |
188 | struct blkg_rwstat merged; | |
189 | /* total time spent on device in ns, may not be accurate w/ queueing */ | |
190 | struct blkg_rwstat service_time; | |
191 | /* total time spent waiting in scheduler queue in ns */ | |
192 | struct blkg_rwstat wait_time; | |
193 | /* number of IOs queued up */ | |
194 | struct blkg_rwstat queued; | |
195 | /* total disk time and nr sectors dispatched by this group */ | |
196 | struct blkg_stat time; | |
197 | #ifdef CONFIG_DEBUG_BLK_CGROUP | |
198 | /* time not charged to this cgroup */ | |
199 | struct blkg_stat unaccounted_time; | |
200 | /* sum of number of ios queued across all samples */ | |
201 | struct blkg_stat avg_queue_size_sum; | |
202 | /* count of samples taken for average */ | |
203 | struct blkg_stat avg_queue_size_samples; | |
204 | /* how many times this group has been removed from service tree */ | |
205 | struct blkg_stat dequeue; | |
206 | /* total time spent waiting for it to be assigned a timeslice. */ | |
207 | struct blkg_stat group_wait_time; | |
208 | /* time spent idling for this blkcg_gq */ | |
209 | struct blkg_stat idle_time; | |
210 | /* total time with empty current active q with other requests queued */ | |
211 | struct blkg_stat empty_time; | |
212 | /* fields after this shouldn't be cleared on stat reset */ | |
213 | uint64_t start_group_wait_time; | |
214 | uint64_t start_idle_time; | |
215 | uint64_t start_empty_time; | |
216 | uint16_t flags; | |
217 | #endif /* CONFIG_DEBUG_BLK_CGROUP */ | |
218 | #endif /* CONFIG_CFQ_GROUP_IOSCHED */ | |
219 | }; | |
220 | ||
221 | /* Per-cgroup data */ | |
222 | struct cfq_group_data { | |
223 | /* must be the first member */ | |
224 | struct blkcg_policy_data cpd; | |
225 | ||
226 | unsigned int weight; | |
227 | unsigned int leaf_weight; | |
228 | }; | |
229 | ||
230 | /* This is per cgroup per device grouping structure */ | |
231 | struct cfq_group { | |
232 | /* must be the first member */ | |
233 | struct blkg_policy_data pd; | |
234 | ||
235 | /* group service_tree member */ | |
236 | struct rb_node rb_node; | |
237 | ||
238 | /* group service_tree key */ | |
239 | u64 vdisktime; | |
240 | ||
241 | /* | |
242 | * The number of active cfqgs and sum of their weights under this | |
243 | * cfqg. This covers this cfqg's leaf_weight and all children's | |
244 | * weights, but does not cover weights of further descendants. | |
245 | * | |
246 | * If a cfqg is on the service tree, it's active. An active cfqg | |
247 | * also activates its parent and contributes to the children_weight | |
248 | * of the parent. | |
249 | */ | |
250 | int nr_active; | |
251 | unsigned int children_weight; | |
252 | ||
253 | /* | |
254 | * vfraction is the fraction of vdisktime that the tasks in this | |
255 | * cfqg are entitled to. This is determined by compounding the | |
256 | * ratios walking up from this cfqg to the root. | |
257 | * | |
258 | * It is in fixed point w/ CFQ_SERVICE_SHIFT and the sum of all | |
259 | * vfractions on a service tree is approximately 1. The sum may | |
260 | * deviate a bit due to rounding errors and fluctuations caused by | |
261 | * cfqgs entering and leaving the service tree. | |
262 | */ | |
263 | unsigned int vfraction; | |
264 | ||
265 | /* | |
266 | * There are two weights - (internal) weight is the weight of this | |
267 | * cfqg against the sibling cfqgs. leaf_weight is the wight of | |
268 | * this cfqg against the child cfqgs. For the root cfqg, both | |
269 | * weights are kept in sync for backward compatibility. | |
270 | */ | |
271 | unsigned int weight; | |
272 | unsigned int new_weight; | |
273 | unsigned int dev_weight; | |
274 | ||
275 | unsigned int leaf_weight; | |
276 | unsigned int new_leaf_weight; | |
277 | unsigned int dev_leaf_weight; | |
278 | ||
279 | /* number of cfqq currently on this group */ | |
280 | int nr_cfqq; | |
281 | ||
282 | /* | |
283 | * Per group busy queues average. Useful for workload slice calc. We | |
284 | * create the array for each prio class but at run time it is used | |
285 | * only for RT and BE class and slot for IDLE class remains unused. | |
286 | * This is primarily done to avoid confusion and a gcc warning. | |
287 | */ | |
288 | unsigned int busy_queues_avg[CFQ_PRIO_NR]; | |
289 | /* | |
290 | * rr lists of queues with requests. We maintain service trees for | |
291 | * RT and BE classes. These trees are subdivided in subclasses | |
292 | * of SYNC, SYNC_NOIDLE and ASYNC based on workload type. For IDLE | |
293 | * class there is no subclassification and all the cfq queues go on | |
294 | * a single tree service_tree_idle. | |
295 | * Counts are embedded in the cfq_rb_root | |
296 | */ | |
297 | struct cfq_rb_root service_trees[2][3]; | |
298 | struct cfq_rb_root service_tree_idle; | |
299 | ||
300 | u64 saved_wl_slice; | |
301 | enum wl_type_t saved_wl_type; | |
302 | enum wl_class_t saved_wl_class; | |
303 | ||
304 | /* number of requests that are on the dispatch list or inside driver */ | |
305 | int dispatched; | |
306 | struct cfq_ttime ttime; | |
307 | struct cfqg_stats stats; /* stats for this cfqg */ | |
308 | ||
309 | /* async queue for each priority case */ | |
310 | struct cfq_queue *async_cfqq[2][IOPRIO_BE_NR]; | |
311 | struct cfq_queue *async_idle_cfqq; | |
312 | ||
313 | }; | |
314 | ||
315 | struct cfq_io_cq { | |
316 | struct io_cq icq; /* must be the first member */ | |
317 | struct cfq_queue *cfqq[2]; | |
318 | struct cfq_ttime ttime; | |
319 | int ioprio; /* the current ioprio */ | |
320 | #ifdef CONFIG_CFQ_GROUP_IOSCHED | |
321 | uint64_t blkcg_serial_nr; /* the current blkcg serial */ | |
322 | #endif | |
323 | }; | |
324 | ||
325 | /* | |
326 | * Per block device queue structure | |
327 | */ | |
328 | struct cfq_data { | |
329 | struct request_queue *queue; | |
330 | /* Root service tree for cfq_groups */ | |
331 | struct cfq_rb_root grp_service_tree; | |
332 | struct cfq_group *root_group; | |
333 | ||
334 | /* | |
335 | * The priority currently being served | |
336 | */ | |
337 | enum wl_class_t serving_wl_class; | |
338 | enum wl_type_t serving_wl_type; | |
339 | u64 workload_expires; | |
340 | struct cfq_group *serving_group; | |
341 | ||
342 | /* | |
343 | * Each priority tree is sorted by next_request position. These | |
344 | * trees are used when determining if two or more queues are | |
345 | * interleaving requests (see cfq_close_cooperator). | |
346 | */ | |
347 | struct rb_root prio_trees[CFQ_PRIO_LISTS]; | |
348 | ||
349 | unsigned int busy_queues; | |
350 | unsigned int busy_sync_queues; | |
351 | ||
352 | int rq_in_driver; | |
353 | int rq_in_flight[2]; | |
354 | ||
355 | /* | |
356 | * queue-depth detection | |
357 | */ | |
358 | int rq_queued; | |
359 | int hw_tag; | |
360 | /* | |
361 | * hw_tag can be | |
362 | * -1 => indeterminate, (cfq will behave as if NCQ is present, to allow better detection) | |
363 | * 1 => NCQ is present (hw_tag_est_depth is the estimated max depth) | |
364 | * 0 => no NCQ | |
365 | */ | |
366 | int hw_tag_est_depth; | |
367 | unsigned int hw_tag_samples; | |
368 | ||
369 | /* | |
370 | * idle window management | |
371 | */ | |
372 | struct hrtimer idle_slice_timer; | |
373 | struct work_struct unplug_work; | |
374 | ||
375 | struct cfq_queue *active_queue; | |
376 | struct cfq_io_cq *active_cic; | |
377 | ||
378 | sector_t last_position; | |
379 | ||
380 | /* | |
381 | * tunables, see top of file | |
382 | */ | |
383 | unsigned int cfq_quantum; | |
384 | unsigned int cfq_back_penalty; | |
385 | unsigned int cfq_back_max; | |
386 | unsigned int cfq_slice_async_rq; | |
387 | unsigned int cfq_latency; | |
388 | u64 cfq_fifo_expire[2]; | |
389 | u64 cfq_slice[2]; | |
390 | u64 cfq_slice_idle; | |
391 | u64 cfq_group_idle; | |
392 | u64 cfq_target_latency; | |
393 | ||
394 | /* | |
395 | * Fallback dummy cfqq for extreme OOM conditions | |
396 | */ | |
397 | struct cfq_queue oom_cfqq; | |
398 | ||
399 | u64 last_delayed_sync; | |
400 | }; | |
401 | ||
402 | static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd); | |
403 | static void cfq_put_queue(struct cfq_queue *cfqq); | |
404 | ||
405 | static struct cfq_rb_root *st_for(struct cfq_group *cfqg, | |
406 | enum wl_class_t class, | |
407 | enum wl_type_t type) | |
408 | { | |
409 | if (!cfqg) | |
410 | return NULL; | |
411 | ||
412 | if (class == IDLE_WORKLOAD) | |
413 | return &cfqg->service_tree_idle; | |
414 | ||
415 | return &cfqg->service_trees[class][type]; | |
416 | } | |
417 | ||
418 | enum cfqq_state_flags { | |
419 | CFQ_CFQQ_FLAG_on_rr = 0, /* on round-robin busy list */ | |
420 | CFQ_CFQQ_FLAG_wait_request, /* waiting for a request */ | |
421 | CFQ_CFQQ_FLAG_must_dispatch, /* must be allowed a dispatch */ | |
422 | CFQ_CFQQ_FLAG_must_alloc_slice, /* per-slice must_alloc flag */ | |
423 | CFQ_CFQQ_FLAG_fifo_expire, /* FIFO checked in this slice */ | |
424 | CFQ_CFQQ_FLAG_idle_window, /* slice idling enabled */ | |
425 | CFQ_CFQQ_FLAG_prio_changed, /* task priority has changed */ | |
426 | CFQ_CFQQ_FLAG_slice_new, /* no requests dispatched in slice */ | |
427 | CFQ_CFQQ_FLAG_sync, /* synchronous queue */ | |
428 | CFQ_CFQQ_FLAG_coop, /* cfqq is shared */ | |
429 | CFQ_CFQQ_FLAG_split_coop, /* shared cfqq will be splitted */ | |
430 | CFQ_CFQQ_FLAG_deep, /* sync cfqq experienced large depth */ | |
431 | CFQ_CFQQ_FLAG_wait_busy, /* Waiting for next request */ | |
432 | }; | |
433 | ||
434 | #define CFQ_CFQQ_FNS(name) \ | |
435 | static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \ | |
436 | { \ | |
437 | (cfqq)->flags |= (1 << CFQ_CFQQ_FLAG_##name); \ | |
438 | } \ | |
439 | static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \ | |
440 | { \ | |
441 | (cfqq)->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \ | |
442 | } \ | |
443 | static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \ | |
444 | { \ | |
445 | return ((cfqq)->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \ | |
446 | } | |
447 | ||
448 | CFQ_CFQQ_FNS(on_rr); | |
449 | CFQ_CFQQ_FNS(wait_request); | |
450 | CFQ_CFQQ_FNS(must_dispatch); | |
451 | CFQ_CFQQ_FNS(must_alloc_slice); | |
452 | CFQ_CFQQ_FNS(fifo_expire); | |
453 | CFQ_CFQQ_FNS(idle_window); | |
454 | CFQ_CFQQ_FNS(prio_changed); | |
455 | CFQ_CFQQ_FNS(slice_new); | |
456 | CFQ_CFQQ_FNS(sync); | |
457 | CFQ_CFQQ_FNS(coop); | |
458 | CFQ_CFQQ_FNS(split_coop); | |
459 | CFQ_CFQQ_FNS(deep); | |
460 | CFQ_CFQQ_FNS(wait_busy); | |
461 | #undef CFQ_CFQQ_FNS | |
462 | ||
463 | #if defined(CONFIG_CFQ_GROUP_IOSCHED) && defined(CONFIG_DEBUG_BLK_CGROUP) | |
464 | ||
465 | /* cfqg stats flags */ | |
466 | enum cfqg_stats_flags { | |
467 | CFQG_stats_waiting = 0, | |
468 | CFQG_stats_idling, | |
469 | CFQG_stats_empty, | |
470 | }; | |
471 | ||
472 | #define CFQG_FLAG_FNS(name) \ | |
473 | static inline void cfqg_stats_mark_##name(struct cfqg_stats *stats) \ | |
474 | { \ | |
475 | stats->flags |= (1 << CFQG_stats_##name); \ | |
476 | } \ | |
477 | static inline void cfqg_stats_clear_##name(struct cfqg_stats *stats) \ | |
478 | { \ | |
479 | stats->flags &= ~(1 << CFQG_stats_##name); \ | |
480 | } \ | |
481 | static inline int cfqg_stats_##name(struct cfqg_stats *stats) \ | |
482 | { \ | |
483 | return (stats->flags & (1 << CFQG_stats_##name)) != 0; \ | |
484 | } \ | |
485 | ||
486 | CFQG_FLAG_FNS(waiting) | |
487 | CFQG_FLAG_FNS(idling) | |
488 | CFQG_FLAG_FNS(empty) | |
489 | #undef CFQG_FLAG_FNS | |
490 | ||
491 | /* This should be called with the queue_lock held. */ | |
492 | static void cfqg_stats_update_group_wait_time(struct cfqg_stats *stats) | |
493 | { | |
494 | unsigned long long now; | |
495 | ||
496 | if (!cfqg_stats_waiting(stats)) | |
497 | return; | |
498 | ||
499 | now = sched_clock(); | |
500 | if (time_after64(now, stats->start_group_wait_time)) | |
501 | blkg_stat_add(&stats->group_wait_time, | |
502 | now - stats->start_group_wait_time); | |
503 | cfqg_stats_clear_waiting(stats); | |
504 | } | |
505 | ||
506 | /* This should be called with the queue_lock held. */ | |
507 | static void cfqg_stats_set_start_group_wait_time(struct cfq_group *cfqg, | |
508 | struct cfq_group *curr_cfqg) | |
509 | { | |
510 | struct cfqg_stats *stats = &cfqg->stats; | |
511 | ||
512 | if (cfqg_stats_waiting(stats)) | |
513 | return; | |
514 | if (cfqg == curr_cfqg) | |
515 | return; | |
516 | stats->start_group_wait_time = sched_clock(); | |
517 | cfqg_stats_mark_waiting(stats); | |
518 | } | |
519 | ||
520 | /* This should be called with the queue_lock held. */ | |
521 | static void cfqg_stats_end_empty_time(struct cfqg_stats *stats) | |
522 | { | |
523 | unsigned long long now; | |
524 | ||
525 | if (!cfqg_stats_empty(stats)) | |
526 | return; | |
527 | ||
528 | now = sched_clock(); | |
529 | if (time_after64(now, stats->start_empty_time)) | |
530 | blkg_stat_add(&stats->empty_time, | |
531 | now - stats->start_empty_time); | |
532 | cfqg_stats_clear_empty(stats); | |
533 | } | |
534 | ||
535 | static void cfqg_stats_update_dequeue(struct cfq_group *cfqg) | |
536 | { | |
537 | blkg_stat_add(&cfqg->stats.dequeue, 1); | |
538 | } | |
539 | ||
540 | static void cfqg_stats_set_start_empty_time(struct cfq_group *cfqg) | |
541 | { | |
542 | struct cfqg_stats *stats = &cfqg->stats; | |
543 | ||
544 | if (blkg_rwstat_total(&stats->queued)) | |
545 | return; | |
546 | ||
547 | /* | |
548 | * group is already marked empty. This can happen if cfqq got new | |
549 | * request in parent group and moved to this group while being added | |
550 | * to service tree. Just ignore the event and move on. | |
551 | */ | |
552 | if (cfqg_stats_empty(stats)) | |
553 | return; | |
554 | ||
555 | stats->start_empty_time = sched_clock(); | |
556 | cfqg_stats_mark_empty(stats); | |
557 | } | |
558 | ||
559 | static void cfqg_stats_update_idle_time(struct cfq_group *cfqg) | |
560 | { | |
561 | struct cfqg_stats *stats = &cfqg->stats; | |
562 | ||
563 | if (cfqg_stats_idling(stats)) { | |
564 | unsigned long long now = sched_clock(); | |
565 | ||
566 | if (time_after64(now, stats->start_idle_time)) | |
567 | blkg_stat_add(&stats->idle_time, | |
568 | now - stats->start_idle_time); | |
569 | cfqg_stats_clear_idling(stats); | |
570 | } | |
571 | } | |
572 | ||
573 | static void cfqg_stats_set_start_idle_time(struct cfq_group *cfqg) | |
574 | { | |
575 | struct cfqg_stats *stats = &cfqg->stats; | |
576 | ||
577 | BUG_ON(cfqg_stats_idling(stats)); | |
578 | ||
579 | stats->start_idle_time = sched_clock(); | |
580 | cfqg_stats_mark_idling(stats); | |
581 | } | |
582 | ||
583 | static void cfqg_stats_update_avg_queue_size(struct cfq_group *cfqg) | |
584 | { | |
585 | struct cfqg_stats *stats = &cfqg->stats; | |
586 | ||
587 | blkg_stat_add(&stats->avg_queue_size_sum, | |
588 | blkg_rwstat_total(&stats->queued)); | |
589 | blkg_stat_add(&stats->avg_queue_size_samples, 1); | |
590 | cfqg_stats_update_group_wait_time(stats); | |
591 | } | |
592 | ||
593 | #else /* CONFIG_CFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */ | |
594 | ||
595 | static inline void cfqg_stats_set_start_group_wait_time(struct cfq_group *cfqg, struct cfq_group *curr_cfqg) { } | |
596 | static inline void cfqg_stats_end_empty_time(struct cfqg_stats *stats) { } | |
597 | static inline void cfqg_stats_update_dequeue(struct cfq_group *cfqg) { } | |
598 | static inline void cfqg_stats_set_start_empty_time(struct cfq_group *cfqg) { } | |
599 | static inline void cfqg_stats_update_idle_time(struct cfq_group *cfqg) { } | |
600 | static inline void cfqg_stats_set_start_idle_time(struct cfq_group *cfqg) { } | |
601 | static inline void cfqg_stats_update_avg_queue_size(struct cfq_group *cfqg) { } | |
602 | ||
603 | #endif /* CONFIG_CFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */ | |
604 | ||
605 | #ifdef CONFIG_CFQ_GROUP_IOSCHED | |
606 | ||
607 | static inline struct cfq_group *pd_to_cfqg(struct blkg_policy_data *pd) | |
608 | { | |
609 | return pd ? container_of(pd, struct cfq_group, pd) : NULL; | |
610 | } | |
611 | ||
612 | static struct cfq_group_data | |
613 | *cpd_to_cfqgd(struct blkcg_policy_data *cpd) | |
614 | { | |
615 | return cpd ? container_of(cpd, struct cfq_group_data, cpd) : NULL; | |
616 | } | |
617 | ||
618 | static inline struct blkcg_gq *cfqg_to_blkg(struct cfq_group *cfqg) | |
619 | { | |
620 | return pd_to_blkg(&cfqg->pd); | |
621 | } | |
622 | ||
623 | static struct blkcg_policy blkcg_policy_cfq; | |
624 | ||
625 | static inline struct cfq_group *blkg_to_cfqg(struct blkcg_gq *blkg) | |
626 | { | |
627 | return pd_to_cfqg(blkg_to_pd(blkg, &blkcg_policy_cfq)); | |
628 | } | |
629 | ||
630 | static struct cfq_group_data *blkcg_to_cfqgd(struct blkcg *blkcg) | |
631 | { | |
632 | return cpd_to_cfqgd(blkcg_to_cpd(blkcg, &blkcg_policy_cfq)); | |
633 | } | |
634 | ||
635 | static inline struct cfq_group *cfqg_parent(struct cfq_group *cfqg) | |
636 | { | |
637 | struct blkcg_gq *pblkg = cfqg_to_blkg(cfqg)->parent; | |
638 | ||
639 | return pblkg ? blkg_to_cfqg(pblkg) : NULL; | |
640 | } | |
641 | ||
642 | static inline bool cfqg_is_descendant(struct cfq_group *cfqg, | |
643 | struct cfq_group *ancestor) | |
644 | { | |
645 | return cgroup_is_descendant(cfqg_to_blkg(cfqg)->blkcg->css.cgroup, | |
646 | cfqg_to_blkg(ancestor)->blkcg->css.cgroup); | |
647 | } | |
648 | ||
649 | static inline void cfqg_get(struct cfq_group *cfqg) | |
650 | { | |
651 | return blkg_get(cfqg_to_blkg(cfqg)); | |
652 | } | |
653 | ||
654 | static inline void cfqg_put(struct cfq_group *cfqg) | |
655 | { | |
656 | return blkg_put(cfqg_to_blkg(cfqg)); | |
657 | } | |
658 | ||
659 | #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) do { \ | |
660 | blk_add_cgroup_trace_msg((cfqd)->queue, \ | |
661 | cfqg_to_blkg((cfqq)->cfqg)->blkcg, \ | |
662 | "cfq%d%c%c " fmt, (cfqq)->pid, \ | |
663 | cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \ | |
664 | cfqq_type((cfqq)) == SYNC_NOIDLE_WORKLOAD ? 'N' : ' ',\ | |
665 | ##args); \ | |
666 | } while (0) | |
667 | ||
668 | #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) do { \ | |
669 | blk_add_cgroup_trace_msg((cfqd)->queue, \ | |
670 | cfqg_to_blkg(cfqg)->blkcg, fmt, ##args); \ | |
671 | } while (0) | |
672 | ||
673 | static inline void cfqg_stats_update_io_add(struct cfq_group *cfqg, | |
674 | struct cfq_group *curr_cfqg, | |
675 | unsigned int op) | |
676 | { | |
677 | blkg_rwstat_add(&cfqg->stats.queued, op, 1); | |
678 | cfqg_stats_end_empty_time(&cfqg->stats); | |
679 | cfqg_stats_set_start_group_wait_time(cfqg, curr_cfqg); | |
680 | } | |
681 | ||
682 | static inline void cfqg_stats_update_timeslice_used(struct cfq_group *cfqg, | |
683 | uint64_t time, unsigned long unaccounted_time) | |
684 | { | |
685 | blkg_stat_add(&cfqg->stats.time, time); | |
686 | #ifdef CONFIG_DEBUG_BLK_CGROUP | |
687 | blkg_stat_add(&cfqg->stats.unaccounted_time, unaccounted_time); | |
688 | #endif | |
689 | } | |
690 | ||
691 | static inline void cfqg_stats_update_io_remove(struct cfq_group *cfqg, | |
692 | unsigned int op) | |
693 | { | |
694 | blkg_rwstat_add(&cfqg->stats.queued, op, -1); | |
695 | } | |
696 | ||
697 | static inline void cfqg_stats_update_io_merged(struct cfq_group *cfqg, | |
698 | unsigned int op) | |
699 | { | |
700 | blkg_rwstat_add(&cfqg->stats.merged, op, 1); | |
701 | } | |
702 | ||
703 | static inline void cfqg_stats_update_completion(struct cfq_group *cfqg, | |
704 | uint64_t start_time, uint64_t io_start_time, | |
705 | unsigned int op) | |
706 | { | |
707 | struct cfqg_stats *stats = &cfqg->stats; | |
708 | unsigned long long now = sched_clock(); | |
709 | ||
710 | if (time_after64(now, io_start_time)) | |
711 | blkg_rwstat_add(&stats->service_time, op, now - io_start_time); | |
712 | if (time_after64(io_start_time, start_time)) | |
713 | blkg_rwstat_add(&stats->wait_time, op, | |
714 | io_start_time - start_time); | |
715 | } | |
716 | ||
717 | /* @stats = 0 */ | |
718 | static void cfqg_stats_reset(struct cfqg_stats *stats) | |
719 | { | |
720 | /* queued stats shouldn't be cleared */ | |
721 | blkg_rwstat_reset(&stats->merged); | |
722 | blkg_rwstat_reset(&stats->service_time); | |
723 | blkg_rwstat_reset(&stats->wait_time); | |
724 | blkg_stat_reset(&stats->time); | |
725 | #ifdef CONFIG_DEBUG_BLK_CGROUP | |
726 | blkg_stat_reset(&stats->unaccounted_time); | |
727 | blkg_stat_reset(&stats->avg_queue_size_sum); | |
728 | blkg_stat_reset(&stats->avg_queue_size_samples); | |
729 | blkg_stat_reset(&stats->dequeue); | |
730 | blkg_stat_reset(&stats->group_wait_time); | |
731 | blkg_stat_reset(&stats->idle_time); | |
732 | blkg_stat_reset(&stats->empty_time); | |
733 | #endif | |
734 | } | |
735 | ||
736 | /* @to += @from */ | |
737 | static void cfqg_stats_add_aux(struct cfqg_stats *to, struct cfqg_stats *from) | |
738 | { | |
739 | /* queued stats shouldn't be cleared */ | |
740 | blkg_rwstat_add_aux(&to->merged, &from->merged); | |
741 | blkg_rwstat_add_aux(&to->service_time, &from->service_time); | |
742 | blkg_rwstat_add_aux(&to->wait_time, &from->wait_time); | |
743 | blkg_stat_add_aux(&from->time, &from->time); | |
744 | #ifdef CONFIG_DEBUG_BLK_CGROUP | |
745 | blkg_stat_add_aux(&to->unaccounted_time, &from->unaccounted_time); | |
746 | blkg_stat_add_aux(&to->avg_queue_size_sum, &from->avg_queue_size_sum); | |
747 | blkg_stat_add_aux(&to->avg_queue_size_samples, &from->avg_queue_size_samples); | |
748 | blkg_stat_add_aux(&to->dequeue, &from->dequeue); | |
749 | blkg_stat_add_aux(&to->group_wait_time, &from->group_wait_time); | |
750 | blkg_stat_add_aux(&to->idle_time, &from->idle_time); | |
751 | blkg_stat_add_aux(&to->empty_time, &from->empty_time); | |
752 | #endif | |
753 | } | |
754 | ||
755 | /* | |
756 | * Transfer @cfqg's stats to its parent's aux counts so that the ancestors' | |
757 | * recursive stats can still account for the amount used by this cfqg after | |
758 | * it's gone. | |
759 | */ | |
760 | static void cfqg_stats_xfer_dead(struct cfq_group *cfqg) | |
761 | { | |
762 | struct cfq_group *parent = cfqg_parent(cfqg); | |
763 | ||
764 | lockdep_assert_held(cfqg_to_blkg(cfqg)->q->queue_lock); | |
765 | ||
766 | if (unlikely(!parent)) | |
767 | return; | |
768 | ||
769 | cfqg_stats_add_aux(&parent->stats, &cfqg->stats); | |
770 | cfqg_stats_reset(&cfqg->stats); | |
771 | } | |
772 | ||
773 | #else /* CONFIG_CFQ_GROUP_IOSCHED */ | |
774 | ||
775 | static inline struct cfq_group *cfqg_parent(struct cfq_group *cfqg) { return NULL; } | |
776 | static inline bool cfqg_is_descendant(struct cfq_group *cfqg, | |
777 | struct cfq_group *ancestor) | |
778 | { | |
779 | return true; | |
780 | } | |
781 | static inline void cfqg_get(struct cfq_group *cfqg) { } | |
782 | static inline void cfqg_put(struct cfq_group *cfqg) { } | |
783 | ||
784 | #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \ | |
785 | blk_add_trace_msg((cfqd)->queue, "cfq%d%c%c " fmt, (cfqq)->pid, \ | |
786 | cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \ | |
787 | cfqq_type((cfqq)) == SYNC_NOIDLE_WORKLOAD ? 'N' : ' ',\ | |
788 | ##args) | |
789 | #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) do {} while (0) | |
790 | ||
791 | static inline void cfqg_stats_update_io_add(struct cfq_group *cfqg, | |
792 | struct cfq_group *curr_cfqg, unsigned int op) { } | |
793 | static inline void cfqg_stats_update_timeslice_used(struct cfq_group *cfqg, | |
794 | uint64_t time, unsigned long unaccounted_time) { } | |
795 | static inline void cfqg_stats_update_io_remove(struct cfq_group *cfqg, | |
796 | unsigned int op) { } | |
797 | static inline void cfqg_stats_update_io_merged(struct cfq_group *cfqg, | |
798 | unsigned int op) { } | |
799 | static inline void cfqg_stats_update_completion(struct cfq_group *cfqg, | |
800 | uint64_t start_time, uint64_t io_start_time, | |
801 | unsigned int op) { } | |
802 | ||
803 | #endif /* CONFIG_CFQ_GROUP_IOSCHED */ | |
804 | ||
805 | #define cfq_log(cfqd, fmt, args...) \ | |
806 | blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args) | |
807 | ||
808 | /* Traverses through cfq group service trees */ | |
809 | #define for_each_cfqg_st(cfqg, i, j, st) \ | |
810 | for (i = 0; i <= IDLE_WORKLOAD; i++) \ | |
811 | for (j = 0, st = i < IDLE_WORKLOAD ? &cfqg->service_trees[i][j]\ | |
812 | : &cfqg->service_tree_idle; \ | |
813 | (i < IDLE_WORKLOAD && j <= SYNC_WORKLOAD) || \ | |
814 | (i == IDLE_WORKLOAD && j == 0); \ | |
815 | j++, st = i < IDLE_WORKLOAD ? \ | |
816 | &cfqg->service_trees[i][j]: NULL) \ | |
817 | ||
818 | static inline bool cfq_io_thinktime_big(struct cfq_data *cfqd, | |
819 | struct cfq_ttime *ttime, bool group_idle) | |
820 | { | |
821 | u64 slice; | |
822 | if (!sample_valid(ttime->ttime_samples)) | |
823 | return false; | |
824 | if (group_idle) | |
825 | slice = cfqd->cfq_group_idle; | |
826 | else | |
827 | slice = cfqd->cfq_slice_idle; | |
828 | return ttime->ttime_mean > slice; | |
829 | } | |
830 | ||
831 | static inline bool iops_mode(struct cfq_data *cfqd) | |
832 | { | |
833 | /* | |
834 | * If we are not idling on queues and it is a NCQ drive, parallel | |
835 | * execution of requests is on and measuring time is not possible | |
836 | * in most of the cases until and unless we drive shallower queue | |
837 | * depths and that becomes a performance bottleneck. In such cases | |
838 | * switch to start providing fairness in terms of number of IOs. | |
839 | */ | |
840 | if (!cfqd->cfq_slice_idle && cfqd->hw_tag) | |
841 | return true; | |
842 | else | |
843 | return false; | |
844 | } | |
845 | ||
846 | static inline enum wl_class_t cfqq_class(struct cfq_queue *cfqq) | |
847 | { | |
848 | if (cfq_class_idle(cfqq)) | |
849 | return IDLE_WORKLOAD; | |
850 | if (cfq_class_rt(cfqq)) | |
851 | return RT_WORKLOAD; | |
852 | return BE_WORKLOAD; | |
853 | } | |
854 | ||
855 | ||
856 | static enum wl_type_t cfqq_type(struct cfq_queue *cfqq) | |
857 | { | |
858 | if (!cfq_cfqq_sync(cfqq)) | |
859 | return ASYNC_WORKLOAD; | |
860 | if (!cfq_cfqq_idle_window(cfqq)) | |
861 | return SYNC_NOIDLE_WORKLOAD; | |
862 | return SYNC_WORKLOAD; | |
863 | } | |
864 | ||
865 | static inline int cfq_group_busy_queues_wl(enum wl_class_t wl_class, | |
866 | struct cfq_data *cfqd, | |
867 | struct cfq_group *cfqg) | |
868 | { | |
869 | if (wl_class == IDLE_WORKLOAD) | |
870 | return cfqg->service_tree_idle.count; | |
871 | ||
872 | return cfqg->service_trees[wl_class][ASYNC_WORKLOAD].count + | |
873 | cfqg->service_trees[wl_class][SYNC_NOIDLE_WORKLOAD].count + | |
874 | cfqg->service_trees[wl_class][SYNC_WORKLOAD].count; | |
875 | } | |
876 | ||
877 | static inline int cfqg_busy_async_queues(struct cfq_data *cfqd, | |
878 | struct cfq_group *cfqg) | |
879 | { | |
880 | return cfqg->service_trees[RT_WORKLOAD][ASYNC_WORKLOAD].count + | |
881 | cfqg->service_trees[BE_WORKLOAD][ASYNC_WORKLOAD].count; | |
882 | } | |
883 | ||
884 | static void cfq_dispatch_insert(struct request_queue *, struct request *); | |
885 | static struct cfq_queue *cfq_get_queue(struct cfq_data *cfqd, bool is_sync, | |
886 | struct cfq_io_cq *cic, struct bio *bio); | |
887 | ||
888 | static inline struct cfq_io_cq *icq_to_cic(struct io_cq *icq) | |
889 | { | |
890 | /* cic->icq is the first member, %NULL will convert to %NULL */ | |
891 | return container_of(icq, struct cfq_io_cq, icq); | |
892 | } | |
893 | ||
894 | static inline struct cfq_io_cq *cfq_cic_lookup(struct cfq_data *cfqd, | |
895 | struct io_context *ioc) | |
896 | { | |
897 | if (ioc) | |
898 | return icq_to_cic(ioc_lookup_icq(ioc, cfqd->queue)); | |
899 | return NULL; | |
900 | } | |
901 | ||
902 | static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_cq *cic, bool is_sync) | |
903 | { | |
904 | return cic->cfqq[is_sync]; | |
905 | } | |
906 | ||
907 | static inline void cic_set_cfqq(struct cfq_io_cq *cic, struct cfq_queue *cfqq, | |
908 | bool is_sync) | |
909 | { | |
910 | cic->cfqq[is_sync] = cfqq; | |
911 | } | |
912 | ||
913 | static inline struct cfq_data *cic_to_cfqd(struct cfq_io_cq *cic) | |
914 | { | |
915 | return cic->icq.q->elevator->elevator_data; | |
916 | } | |
917 | ||
918 | /* | |
919 | * scheduler run of queue, if there are requests pending and no one in the | |
920 | * driver that will restart queueing | |
921 | */ | |
922 | static inline void cfq_schedule_dispatch(struct cfq_data *cfqd) | |
923 | { | |
924 | if (cfqd->busy_queues) { | |
925 | cfq_log(cfqd, "schedule dispatch"); | |
926 | kblockd_schedule_work(&cfqd->unplug_work); | |
927 | } | |
928 | } | |
929 | ||
930 | /* | |
931 | * Scale schedule slice based on io priority. Use the sync time slice only | |
932 | * if a queue is marked sync and has sync io queued. A sync queue with async | |
933 | * io only, should not get full sync slice length. | |
934 | */ | |
935 | static inline u64 cfq_prio_slice(struct cfq_data *cfqd, bool sync, | |
936 | unsigned short prio) | |
937 | { | |
938 | u64 base_slice = cfqd->cfq_slice[sync]; | |
939 | u64 slice = div_u64(base_slice, CFQ_SLICE_SCALE); | |
940 | ||
941 | WARN_ON(prio >= IOPRIO_BE_NR); | |
942 | ||
943 | return base_slice + (slice * (4 - prio)); | |
944 | } | |
945 | ||
946 | static inline u64 | |
947 | cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
948 | { | |
949 | return cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio); | |
950 | } | |
951 | ||
952 | /** | |
953 | * cfqg_scale_charge - scale disk time charge according to cfqg weight | |
954 | * @charge: disk time being charged | |
955 | * @vfraction: vfraction of the cfqg, fixed point w/ CFQ_SERVICE_SHIFT | |
956 | * | |
957 | * Scale @charge according to @vfraction, which is in range (0, 1]. The | |
958 | * scaling is inversely proportional. | |
959 | * | |
960 | * scaled = charge / vfraction | |
961 | * | |
962 | * The result is also in fixed point w/ CFQ_SERVICE_SHIFT. | |
963 | */ | |
964 | static inline u64 cfqg_scale_charge(u64 charge, | |
965 | unsigned int vfraction) | |
966 | { | |
967 | u64 c = charge << CFQ_SERVICE_SHIFT; /* make it fixed point */ | |
968 | ||
969 | /* charge / vfraction */ | |
970 | c <<= CFQ_SERVICE_SHIFT; | |
971 | return div_u64(c, vfraction); | |
972 | } | |
973 | ||
974 | static inline u64 max_vdisktime(u64 min_vdisktime, u64 vdisktime) | |
975 | { | |
976 | s64 delta = (s64)(vdisktime - min_vdisktime); | |
977 | if (delta > 0) | |
978 | min_vdisktime = vdisktime; | |
979 | ||
980 | return min_vdisktime; | |
981 | } | |
982 | ||
983 | static void update_min_vdisktime(struct cfq_rb_root *st) | |
984 | { | |
985 | if (!RB_EMPTY_ROOT(&st->rb.rb_root)) { | |
986 | struct cfq_group *cfqg = rb_entry_cfqg(st->rb.rb_leftmost); | |
987 | ||
988 | st->min_vdisktime = max_vdisktime(st->min_vdisktime, | |
989 | cfqg->vdisktime); | |
990 | } | |
991 | } | |
992 | ||
993 | /* | |
994 | * get averaged number of queues of RT/BE priority. | |
995 | * average is updated, with a formula that gives more weight to higher numbers, | |
996 | * to quickly follows sudden increases and decrease slowly | |
997 | */ | |
998 | ||
999 | static inline unsigned cfq_group_get_avg_queues(struct cfq_data *cfqd, | |
1000 | struct cfq_group *cfqg, bool rt) | |
1001 | { | |
1002 | unsigned min_q, max_q; | |
1003 | unsigned mult = cfq_hist_divisor - 1; | |
1004 | unsigned round = cfq_hist_divisor / 2; | |
1005 | unsigned busy = cfq_group_busy_queues_wl(rt, cfqd, cfqg); | |
1006 | ||
1007 | min_q = min(cfqg->busy_queues_avg[rt], busy); | |
1008 | max_q = max(cfqg->busy_queues_avg[rt], busy); | |
1009 | cfqg->busy_queues_avg[rt] = (mult * max_q + min_q + round) / | |
1010 | cfq_hist_divisor; | |
1011 | return cfqg->busy_queues_avg[rt]; | |
1012 | } | |
1013 | ||
1014 | static inline u64 | |
1015 | cfq_group_slice(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
1016 | { | |
1017 | return cfqd->cfq_target_latency * cfqg->vfraction >> CFQ_SERVICE_SHIFT; | |
1018 | } | |
1019 | ||
1020 | static inline u64 | |
1021 | cfq_scaled_cfqq_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1022 | { | |
1023 | u64 slice = cfq_prio_to_slice(cfqd, cfqq); | |
1024 | if (cfqd->cfq_latency) { | |
1025 | /* | |
1026 | * interested queues (we consider only the ones with the same | |
1027 | * priority class in the cfq group) | |
1028 | */ | |
1029 | unsigned iq = cfq_group_get_avg_queues(cfqd, cfqq->cfqg, | |
1030 | cfq_class_rt(cfqq)); | |
1031 | u64 sync_slice = cfqd->cfq_slice[1]; | |
1032 | u64 expect_latency = sync_slice * iq; | |
1033 | u64 group_slice = cfq_group_slice(cfqd, cfqq->cfqg); | |
1034 | ||
1035 | if (expect_latency > group_slice) { | |
1036 | u64 base_low_slice = 2 * cfqd->cfq_slice_idle; | |
1037 | u64 low_slice; | |
1038 | ||
1039 | /* scale low_slice according to IO priority | |
1040 | * and sync vs async */ | |
1041 | low_slice = div64_u64(base_low_slice*slice, sync_slice); | |
1042 | low_slice = min(slice, low_slice); | |
1043 | /* the adapted slice value is scaled to fit all iqs | |
1044 | * into the target latency */ | |
1045 | slice = div64_u64(slice*group_slice, expect_latency); | |
1046 | slice = max(slice, low_slice); | |
1047 | } | |
1048 | } | |
1049 | return slice; | |
1050 | } | |
1051 | ||
1052 | static inline void | |
1053 | cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1054 | { | |
1055 | u64 slice = cfq_scaled_cfqq_slice(cfqd, cfqq); | |
1056 | u64 now = ktime_get_ns(); | |
1057 | ||
1058 | cfqq->slice_start = now; | |
1059 | cfqq->slice_end = now + slice; | |
1060 | cfqq->allocated_slice = slice; | |
1061 | cfq_log_cfqq(cfqd, cfqq, "set_slice=%llu", cfqq->slice_end - now); | |
1062 | } | |
1063 | ||
1064 | /* | |
1065 | * We need to wrap this check in cfq_cfqq_slice_new(), since ->slice_end | |
1066 | * isn't valid until the first request from the dispatch is activated | |
1067 | * and the slice time set. | |
1068 | */ | |
1069 | static inline bool cfq_slice_used(struct cfq_queue *cfqq) | |
1070 | { | |
1071 | if (cfq_cfqq_slice_new(cfqq)) | |
1072 | return false; | |
1073 | if (ktime_get_ns() < cfqq->slice_end) | |
1074 | return false; | |
1075 | ||
1076 | return true; | |
1077 | } | |
1078 | ||
1079 | /* | |
1080 | * Lifted from AS - choose which of rq1 and rq2 that is best served now. | |
1081 | * We choose the request that is closest to the head right now. Distance | |
1082 | * behind the head is penalized and only allowed to a certain extent. | |
1083 | */ | |
1084 | static struct request * | |
1085 | cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2, sector_t last) | |
1086 | { | |
1087 | sector_t s1, s2, d1 = 0, d2 = 0; | |
1088 | unsigned long back_max; | |
1089 | #define CFQ_RQ1_WRAP 0x01 /* request 1 wraps */ | |
1090 | #define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */ | |
1091 | unsigned wrap = 0; /* bit mask: requests behind the disk head? */ | |
1092 | ||
1093 | if (rq1 == NULL || rq1 == rq2) | |
1094 | return rq2; | |
1095 | if (rq2 == NULL) | |
1096 | return rq1; | |
1097 | ||
1098 | if (rq_is_sync(rq1) != rq_is_sync(rq2)) | |
1099 | return rq_is_sync(rq1) ? rq1 : rq2; | |
1100 | ||
1101 | if ((rq1->cmd_flags ^ rq2->cmd_flags) & REQ_PRIO) | |
1102 | return rq1->cmd_flags & REQ_PRIO ? rq1 : rq2; | |
1103 | ||
1104 | s1 = blk_rq_pos(rq1); | |
1105 | s2 = blk_rq_pos(rq2); | |
1106 | ||
1107 | /* | |
1108 | * by definition, 1KiB is 2 sectors | |
1109 | */ | |
1110 | back_max = cfqd->cfq_back_max * 2; | |
1111 | ||
1112 | /* | |
1113 | * Strict one way elevator _except_ in the case where we allow | |
1114 | * short backward seeks which are biased as twice the cost of a | |
1115 | * similar forward seek. | |
1116 | */ | |
1117 | if (s1 >= last) | |
1118 | d1 = s1 - last; | |
1119 | else if (s1 + back_max >= last) | |
1120 | d1 = (last - s1) * cfqd->cfq_back_penalty; | |
1121 | else | |
1122 | wrap |= CFQ_RQ1_WRAP; | |
1123 | ||
1124 | if (s2 >= last) | |
1125 | d2 = s2 - last; | |
1126 | else if (s2 + back_max >= last) | |
1127 | d2 = (last - s2) * cfqd->cfq_back_penalty; | |
1128 | else | |
1129 | wrap |= CFQ_RQ2_WRAP; | |
1130 | ||
1131 | /* Found required data */ | |
1132 | ||
1133 | /* | |
1134 | * By doing switch() on the bit mask "wrap" we avoid having to | |
1135 | * check two variables for all permutations: --> faster! | |
1136 | */ | |
1137 | switch (wrap) { | |
1138 | case 0: /* common case for CFQ: rq1 and rq2 not wrapped */ | |
1139 | if (d1 < d2) | |
1140 | return rq1; | |
1141 | else if (d2 < d1) | |
1142 | return rq2; | |
1143 | else { | |
1144 | if (s1 >= s2) | |
1145 | return rq1; | |
1146 | else | |
1147 | return rq2; | |
1148 | } | |
1149 | ||
1150 | case CFQ_RQ2_WRAP: | |
1151 | return rq1; | |
1152 | case CFQ_RQ1_WRAP: | |
1153 | return rq2; | |
1154 | case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both rqs wrapped */ | |
1155 | default: | |
1156 | /* | |
1157 | * Since both rqs are wrapped, | |
1158 | * start with the one that's further behind head | |
1159 | * (--> only *one* back seek required), | |
1160 | * since back seek takes more time than forward. | |
1161 | */ | |
1162 | if (s1 <= s2) | |
1163 | return rq1; | |
1164 | else | |
1165 | return rq2; | |
1166 | } | |
1167 | } | |
1168 | ||
1169 | static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root) | |
1170 | { | |
1171 | /* Service tree is empty */ | |
1172 | if (!root->count) | |
1173 | return NULL; | |
1174 | ||
1175 | return rb_entry(rb_first_cached(&root->rb), struct cfq_queue, rb_node); | |
1176 | } | |
1177 | ||
1178 | static struct cfq_group *cfq_rb_first_group(struct cfq_rb_root *root) | |
1179 | { | |
1180 | return rb_entry_cfqg(rb_first_cached(&root->rb)); | |
1181 | } | |
1182 | ||
1183 | static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root) | |
1184 | { | |
1185 | if (root->rb_rightmost == n) | |
1186 | root->rb_rightmost = rb_prev(n); | |
1187 | ||
1188 | rb_erase_cached(n, &root->rb); | |
1189 | RB_CLEAR_NODE(n); | |
1190 | ||
1191 | --root->count; | |
1192 | } | |
1193 | ||
1194 | /* | |
1195 | * would be nice to take fifo expire time into account as well | |
1196 | */ | |
1197 | static struct request * | |
1198 | cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
1199 | struct request *last) | |
1200 | { | |
1201 | struct rb_node *rbnext = rb_next(&last->rb_node); | |
1202 | struct rb_node *rbprev = rb_prev(&last->rb_node); | |
1203 | struct request *next = NULL, *prev = NULL; | |
1204 | ||
1205 | BUG_ON(RB_EMPTY_NODE(&last->rb_node)); | |
1206 | ||
1207 | if (rbprev) | |
1208 | prev = rb_entry_rq(rbprev); | |
1209 | ||
1210 | if (rbnext) | |
1211 | next = rb_entry_rq(rbnext); | |
1212 | else { | |
1213 | rbnext = rb_first(&cfqq->sort_list); | |
1214 | if (rbnext && rbnext != &last->rb_node) | |
1215 | next = rb_entry_rq(rbnext); | |
1216 | } | |
1217 | ||
1218 | return cfq_choose_req(cfqd, next, prev, blk_rq_pos(last)); | |
1219 | } | |
1220 | ||
1221 | static u64 cfq_slice_offset(struct cfq_data *cfqd, | |
1222 | struct cfq_queue *cfqq) | |
1223 | { | |
1224 | /* | |
1225 | * just an approximation, should be ok. | |
1226 | */ | |
1227 | return (cfqq->cfqg->nr_cfqq - 1) * (cfq_prio_slice(cfqd, 1, 0) - | |
1228 | cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio)); | |
1229 | } | |
1230 | ||
1231 | static inline s64 | |
1232 | cfqg_key(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
1233 | { | |
1234 | return cfqg->vdisktime - st->min_vdisktime; | |
1235 | } | |
1236 | ||
1237 | static void | |
1238 | __cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
1239 | { | |
1240 | struct rb_node **node = &st->rb.rb_root.rb_node; | |
1241 | struct rb_node *parent = NULL; | |
1242 | struct cfq_group *__cfqg; | |
1243 | s64 key = cfqg_key(st, cfqg); | |
1244 | bool leftmost = true, rightmost = true; | |
1245 | ||
1246 | while (*node != NULL) { | |
1247 | parent = *node; | |
1248 | __cfqg = rb_entry_cfqg(parent); | |
1249 | ||
1250 | if (key < cfqg_key(st, __cfqg)) { | |
1251 | node = &parent->rb_left; | |
1252 | rightmost = false; | |
1253 | } else { | |
1254 | node = &parent->rb_right; | |
1255 | leftmost = false; | |
1256 | } | |
1257 | } | |
1258 | ||
1259 | if (rightmost) | |
1260 | st->rb_rightmost = &cfqg->rb_node; | |
1261 | ||
1262 | rb_link_node(&cfqg->rb_node, parent, node); | |
1263 | rb_insert_color_cached(&cfqg->rb_node, &st->rb, leftmost); | |
1264 | } | |
1265 | ||
1266 | /* | |
1267 | * This has to be called only on activation of cfqg | |
1268 | */ | |
1269 | static void | |
1270 | cfq_update_group_weight(struct cfq_group *cfqg) | |
1271 | { | |
1272 | if (cfqg->new_weight) { | |
1273 | cfqg->weight = cfqg->new_weight; | |
1274 | cfqg->new_weight = 0; | |
1275 | } | |
1276 | } | |
1277 | ||
1278 | static void | |
1279 | cfq_update_group_leaf_weight(struct cfq_group *cfqg) | |
1280 | { | |
1281 | BUG_ON(!RB_EMPTY_NODE(&cfqg->rb_node)); | |
1282 | ||
1283 | if (cfqg->new_leaf_weight) { | |
1284 | cfqg->leaf_weight = cfqg->new_leaf_weight; | |
1285 | cfqg->new_leaf_weight = 0; | |
1286 | } | |
1287 | } | |
1288 | ||
1289 | static void | |
1290 | cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
1291 | { | |
1292 | unsigned int vfr = 1 << CFQ_SERVICE_SHIFT; /* start with 1 */ | |
1293 | struct cfq_group *pos = cfqg; | |
1294 | struct cfq_group *parent; | |
1295 | bool propagate; | |
1296 | ||
1297 | /* add to the service tree */ | |
1298 | BUG_ON(!RB_EMPTY_NODE(&cfqg->rb_node)); | |
1299 | ||
1300 | /* | |
1301 | * Update leaf_weight. We cannot update weight at this point | |
1302 | * because cfqg might already have been activated and is | |
1303 | * contributing its current weight to the parent's child_weight. | |
1304 | */ | |
1305 | cfq_update_group_leaf_weight(cfqg); | |
1306 | __cfq_group_service_tree_add(st, cfqg); | |
1307 | ||
1308 | /* | |
1309 | * Activate @cfqg and calculate the portion of vfraction @cfqg is | |
1310 | * entitled to. vfraction is calculated by walking the tree | |
1311 | * towards the root calculating the fraction it has at each level. | |
1312 | * The compounded ratio is how much vfraction @cfqg owns. | |
1313 | * | |
1314 | * Start with the proportion tasks in this cfqg has against active | |
1315 | * children cfqgs - its leaf_weight against children_weight. | |
1316 | */ | |
1317 | propagate = !pos->nr_active++; | |
1318 | pos->children_weight += pos->leaf_weight; | |
1319 | vfr = vfr * pos->leaf_weight / pos->children_weight; | |
1320 | ||
1321 | /* | |
1322 | * Compound ->weight walking up the tree. Both activation and | |
1323 | * vfraction calculation are done in the same loop. Propagation | |
1324 | * stops once an already activated node is met. vfraction | |
1325 | * calculation should always continue to the root. | |
1326 | */ | |
1327 | while ((parent = cfqg_parent(pos))) { | |
1328 | if (propagate) { | |
1329 | cfq_update_group_weight(pos); | |
1330 | propagate = !parent->nr_active++; | |
1331 | parent->children_weight += pos->weight; | |
1332 | } | |
1333 | vfr = vfr * pos->weight / parent->children_weight; | |
1334 | pos = parent; | |
1335 | } | |
1336 | ||
1337 | cfqg->vfraction = max_t(unsigned, vfr, 1); | |
1338 | } | |
1339 | ||
1340 | static inline u64 cfq_get_cfqg_vdisktime_delay(struct cfq_data *cfqd) | |
1341 | { | |
1342 | if (!iops_mode(cfqd)) | |
1343 | return CFQ_SLICE_MODE_GROUP_DELAY; | |
1344 | else | |
1345 | return CFQ_IOPS_MODE_GROUP_DELAY; | |
1346 | } | |
1347 | ||
1348 | static void | |
1349 | cfq_group_notify_queue_add(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
1350 | { | |
1351 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
1352 | struct cfq_group *__cfqg; | |
1353 | struct rb_node *n; | |
1354 | ||
1355 | cfqg->nr_cfqq++; | |
1356 | if (!RB_EMPTY_NODE(&cfqg->rb_node)) | |
1357 | return; | |
1358 | ||
1359 | /* | |
1360 | * Currently put the group at the end. Later implement something | |
1361 | * so that groups get lesser vtime based on their weights, so that | |
1362 | * if group does not loose all if it was not continuously backlogged. | |
1363 | */ | |
1364 | n = st->rb_rightmost; | |
1365 | if (n) { | |
1366 | __cfqg = rb_entry_cfqg(n); | |
1367 | cfqg->vdisktime = __cfqg->vdisktime + | |
1368 | cfq_get_cfqg_vdisktime_delay(cfqd); | |
1369 | } else | |
1370 | cfqg->vdisktime = st->min_vdisktime; | |
1371 | cfq_group_service_tree_add(st, cfqg); | |
1372 | } | |
1373 | ||
1374 | static void | |
1375 | cfq_group_service_tree_del(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
1376 | { | |
1377 | struct cfq_group *pos = cfqg; | |
1378 | bool propagate; | |
1379 | ||
1380 | /* | |
1381 | * Undo activation from cfq_group_service_tree_add(). Deactivate | |
1382 | * @cfqg and propagate deactivation upwards. | |
1383 | */ | |
1384 | propagate = !--pos->nr_active; | |
1385 | pos->children_weight -= pos->leaf_weight; | |
1386 | ||
1387 | while (propagate) { | |
1388 | struct cfq_group *parent = cfqg_parent(pos); | |
1389 | ||
1390 | /* @pos has 0 nr_active at this point */ | |
1391 | WARN_ON_ONCE(pos->children_weight); | |
1392 | pos->vfraction = 0; | |
1393 | ||
1394 | if (!parent) | |
1395 | break; | |
1396 | ||
1397 | propagate = !--parent->nr_active; | |
1398 | parent->children_weight -= pos->weight; | |
1399 | pos = parent; | |
1400 | } | |
1401 | ||
1402 | /* remove from the service tree */ | |
1403 | if (!RB_EMPTY_NODE(&cfqg->rb_node)) | |
1404 | cfq_rb_erase(&cfqg->rb_node, st); | |
1405 | } | |
1406 | ||
1407 | static void | |
1408 | cfq_group_notify_queue_del(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
1409 | { | |
1410 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
1411 | ||
1412 | BUG_ON(cfqg->nr_cfqq < 1); | |
1413 | cfqg->nr_cfqq--; | |
1414 | ||
1415 | /* If there are other cfq queues under this group, don't delete it */ | |
1416 | if (cfqg->nr_cfqq) | |
1417 | return; | |
1418 | ||
1419 | cfq_log_cfqg(cfqd, cfqg, "del_from_rr group"); | |
1420 | cfq_group_service_tree_del(st, cfqg); | |
1421 | cfqg->saved_wl_slice = 0; | |
1422 | cfqg_stats_update_dequeue(cfqg); | |
1423 | } | |
1424 | ||
1425 | static inline u64 cfq_cfqq_slice_usage(struct cfq_queue *cfqq, | |
1426 | u64 *unaccounted_time) | |
1427 | { | |
1428 | u64 slice_used; | |
1429 | u64 now = ktime_get_ns(); | |
1430 | ||
1431 | /* | |
1432 | * Queue got expired before even a single request completed or | |
1433 | * got expired immediately after first request completion. | |
1434 | */ | |
1435 | if (!cfqq->slice_start || cfqq->slice_start == now) { | |
1436 | /* | |
1437 | * Also charge the seek time incurred to the group, otherwise | |
1438 | * if there are mutiple queues in the group, each can dispatch | |
1439 | * a single request on seeky media and cause lots of seek time | |
1440 | * and group will never know it. | |
1441 | */ | |
1442 | slice_used = max_t(u64, (now - cfqq->dispatch_start), | |
1443 | jiffies_to_nsecs(1)); | |
1444 | } else { | |
1445 | slice_used = now - cfqq->slice_start; | |
1446 | if (slice_used > cfqq->allocated_slice) { | |
1447 | *unaccounted_time = slice_used - cfqq->allocated_slice; | |
1448 | slice_used = cfqq->allocated_slice; | |
1449 | } | |
1450 | if (cfqq->slice_start > cfqq->dispatch_start) | |
1451 | *unaccounted_time += cfqq->slice_start - | |
1452 | cfqq->dispatch_start; | |
1453 | } | |
1454 | ||
1455 | return slice_used; | |
1456 | } | |
1457 | ||
1458 | static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg, | |
1459 | struct cfq_queue *cfqq) | |
1460 | { | |
1461 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
1462 | u64 used_sl, charge, unaccounted_sl = 0; | |
1463 | int nr_sync = cfqg->nr_cfqq - cfqg_busy_async_queues(cfqd, cfqg) | |
1464 | - cfqg->service_tree_idle.count; | |
1465 | unsigned int vfr; | |
1466 | u64 now = ktime_get_ns(); | |
1467 | ||
1468 | BUG_ON(nr_sync < 0); | |
1469 | used_sl = charge = cfq_cfqq_slice_usage(cfqq, &unaccounted_sl); | |
1470 | ||
1471 | if (iops_mode(cfqd)) | |
1472 | charge = cfqq->slice_dispatch; | |
1473 | else if (!cfq_cfqq_sync(cfqq) && !nr_sync) | |
1474 | charge = cfqq->allocated_slice; | |
1475 | ||
1476 | /* | |
1477 | * Can't update vdisktime while on service tree and cfqg->vfraction | |
1478 | * is valid only while on it. Cache vfr, leave the service tree, | |
1479 | * update vdisktime and go back on. The re-addition to the tree | |
1480 | * will also update the weights as necessary. | |
1481 | */ | |
1482 | vfr = cfqg->vfraction; | |
1483 | cfq_group_service_tree_del(st, cfqg); | |
1484 | cfqg->vdisktime += cfqg_scale_charge(charge, vfr); | |
1485 | cfq_group_service_tree_add(st, cfqg); | |
1486 | ||
1487 | /* This group is being expired. Save the context */ | |
1488 | if (cfqd->workload_expires > now) { | |
1489 | cfqg->saved_wl_slice = cfqd->workload_expires - now; | |
1490 | cfqg->saved_wl_type = cfqd->serving_wl_type; | |
1491 | cfqg->saved_wl_class = cfqd->serving_wl_class; | |
1492 | } else | |
1493 | cfqg->saved_wl_slice = 0; | |
1494 | ||
1495 | cfq_log_cfqg(cfqd, cfqg, "served: vt=%llu min_vt=%llu", cfqg->vdisktime, | |
1496 | st->min_vdisktime); | |
1497 | cfq_log_cfqq(cfqq->cfqd, cfqq, | |
1498 | "sl_used=%llu disp=%llu charge=%llu iops=%u sect=%lu", | |
1499 | used_sl, cfqq->slice_dispatch, charge, | |
1500 | iops_mode(cfqd), cfqq->nr_sectors); | |
1501 | cfqg_stats_update_timeslice_used(cfqg, used_sl, unaccounted_sl); | |
1502 | cfqg_stats_set_start_empty_time(cfqg); | |
1503 | } | |
1504 | ||
1505 | /** | |
1506 | * cfq_init_cfqg_base - initialize base part of a cfq_group | |
1507 | * @cfqg: cfq_group to initialize | |
1508 | * | |
1509 | * Initialize the base part which is used whether %CONFIG_CFQ_GROUP_IOSCHED | |
1510 | * is enabled or not. | |
1511 | */ | |
1512 | static void cfq_init_cfqg_base(struct cfq_group *cfqg) | |
1513 | { | |
1514 | struct cfq_rb_root *st; | |
1515 | int i, j; | |
1516 | ||
1517 | for_each_cfqg_st(cfqg, i, j, st) | |
1518 | *st = CFQ_RB_ROOT; | |
1519 | RB_CLEAR_NODE(&cfqg->rb_node); | |
1520 | ||
1521 | cfqg->ttime.last_end_request = ktime_get_ns(); | |
1522 | } | |
1523 | ||
1524 | #ifdef CONFIG_CFQ_GROUP_IOSCHED | |
1525 | static int __cfq_set_weight(struct cgroup_subsys_state *css, u64 val, | |
1526 | bool on_dfl, bool reset_dev, bool is_leaf_weight); | |
1527 | ||
1528 | static void cfqg_stats_exit(struct cfqg_stats *stats) | |
1529 | { | |
1530 | blkg_rwstat_exit(&stats->merged); | |
1531 | blkg_rwstat_exit(&stats->service_time); | |
1532 | blkg_rwstat_exit(&stats->wait_time); | |
1533 | blkg_rwstat_exit(&stats->queued); | |
1534 | blkg_stat_exit(&stats->time); | |
1535 | #ifdef CONFIG_DEBUG_BLK_CGROUP | |
1536 | blkg_stat_exit(&stats->unaccounted_time); | |
1537 | blkg_stat_exit(&stats->avg_queue_size_sum); | |
1538 | blkg_stat_exit(&stats->avg_queue_size_samples); | |
1539 | blkg_stat_exit(&stats->dequeue); | |
1540 | blkg_stat_exit(&stats->group_wait_time); | |
1541 | blkg_stat_exit(&stats->idle_time); | |
1542 | blkg_stat_exit(&stats->empty_time); | |
1543 | #endif | |
1544 | } | |
1545 | ||
1546 | static int cfqg_stats_init(struct cfqg_stats *stats, gfp_t gfp) | |
1547 | { | |
1548 | if (blkg_rwstat_init(&stats->merged, gfp) || | |
1549 | blkg_rwstat_init(&stats->service_time, gfp) || | |
1550 | blkg_rwstat_init(&stats->wait_time, gfp) || | |
1551 | blkg_rwstat_init(&stats->queued, gfp) || | |
1552 | blkg_stat_init(&stats->time, gfp)) | |
1553 | goto err; | |
1554 | ||
1555 | #ifdef CONFIG_DEBUG_BLK_CGROUP | |
1556 | if (blkg_stat_init(&stats->unaccounted_time, gfp) || | |
1557 | blkg_stat_init(&stats->avg_queue_size_sum, gfp) || | |
1558 | blkg_stat_init(&stats->avg_queue_size_samples, gfp) || | |
1559 | blkg_stat_init(&stats->dequeue, gfp) || | |
1560 | blkg_stat_init(&stats->group_wait_time, gfp) || | |
1561 | blkg_stat_init(&stats->idle_time, gfp) || | |
1562 | blkg_stat_init(&stats->empty_time, gfp)) | |
1563 | goto err; | |
1564 | #endif | |
1565 | return 0; | |
1566 | err: | |
1567 | cfqg_stats_exit(stats); | |
1568 | return -ENOMEM; | |
1569 | } | |
1570 | ||
1571 | static struct blkcg_policy_data *cfq_cpd_alloc(gfp_t gfp) | |
1572 | { | |
1573 | struct cfq_group_data *cgd; | |
1574 | ||
1575 | cgd = kzalloc(sizeof(*cgd), gfp); | |
1576 | if (!cgd) | |
1577 | return NULL; | |
1578 | return &cgd->cpd; | |
1579 | } | |
1580 | ||
1581 | static void cfq_cpd_init(struct blkcg_policy_data *cpd) | |
1582 | { | |
1583 | struct cfq_group_data *cgd = cpd_to_cfqgd(cpd); | |
1584 | unsigned int weight = cgroup_subsys_on_dfl(io_cgrp_subsys) ? | |
1585 | CGROUP_WEIGHT_DFL : CFQ_WEIGHT_LEGACY_DFL; | |
1586 | ||
1587 | if (cpd_to_blkcg(cpd) == &blkcg_root) | |
1588 | weight *= 2; | |
1589 | ||
1590 | cgd->weight = weight; | |
1591 | cgd->leaf_weight = weight; | |
1592 | } | |
1593 | ||
1594 | static void cfq_cpd_free(struct blkcg_policy_data *cpd) | |
1595 | { | |
1596 | kfree(cpd_to_cfqgd(cpd)); | |
1597 | } | |
1598 | ||
1599 | static void cfq_cpd_bind(struct blkcg_policy_data *cpd) | |
1600 | { | |
1601 | struct blkcg *blkcg = cpd_to_blkcg(cpd); | |
1602 | bool on_dfl = cgroup_subsys_on_dfl(io_cgrp_subsys); | |
1603 | unsigned int weight = on_dfl ? CGROUP_WEIGHT_DFL : CFQ_WEIGHT_LEGACY_DFL; | |
1604 | ||
1605 | if (blkcg == &blkcg_root) | |
1606 | weight *= 2; | |
1607 | ||
1608 | WARN_ON_ONCE(__cfq_set_weight(&blkcg->css, weight, on_dfl, true, false)); | |
1609 | WARN_ON_ONCE(__cfq_set_weight(&blkcg->css, weight, on_dfl, true, true)); | |
1610 | } | |
1611 | ||
1612 | static struct blkg_policy_data *cfq_pd_alloc(gfp_t gfp, int node) | |
1613 | { | |
1614 | struct cfq_group *cfqg; | |
1615 | ||
1616 | cfqg = kzalloc_node(sizeof(*cfqg), gfp, node); | |
1617 | if (!cfqg) | |
1618 | return NULL; | |
1619 | ||
1620 | cfq_init_cfqg_base(cfqg); | |
1621 | if (cfqg_stats_init(&cfqg->stats, gfp)) { | |
1622 | kfree(cfqg); | |
1623 | return NULL; | |
1624 | } | |
1625 | ||
1626 | return &cfqg->pd; | |
1627 | } | |
1628 | ||
1629 | static void cfq_pd_init(struct blkg_policy_data *pd) | |
1630 | { | |
1631 | struct cfq_group *cfqg = pd_to_cfqg(pd); | |
1632 | struct cfq_group_data *cgd = blkcg_to_cfqgd(pd->blkg->blkcg); | |
1633 | ||
1634 | cfqg->weight = cgd->weight; | |
1635 | cfqg->leaf_weight = cgd->leaf_weight; | |
1636 | } | |
1637 | ||
1638 | static void cfq_pd_offline(struct blkg_policy_data *pd) | |
1639 | { | |
1640 | struct cfq_group *cfqg = pd_to_cfqg(pd); | |
1641 | int i; | |
1642 | ||
1643 | for (i = 0; i < IOPRIO_BE_NR; i++) { | |
1644 | if (cfqg->async_cfqq[0][i]) | |
1645 | cfq_put_queue(cfqg->async_cfqq[0][i]); | |
1646 | if (cfqg->async_cfqq[1][i]) | |
1647 | cfq_put_queue(cfqg->async_cfqq[1][i]); | |
1648 | } | |
1649 | ||
1650 | if (cfqg->async_idle_cfqq) | |
1651 | cfq_put_queue(cfqg->async_idle_cfqq); | |
1652 | ||
1653 | /* | |
1654 | * @blkg is going offline and will be ignored by | |
1655 | * blkg_[rw]stat_recursive_sum(). Transfer stats to the parent so | |
1656 | * that they don't get lost. If IOs complete after this point, the | |
1657 | * stats for them will be lost. Oh well... | |
1658 | */ | |
1659 | cfqg_stats_xfer_dead(cfqg); | |
1660 | } | |
1661 | ||
1662 | static void cfq_pd_free(struct blkg_policy_data *pd) | |
1663 | { | |
1664 | struct cfq_group *cfqg = pd_to_cfqg(pd); | |
1665 | ||
1666 | cfqg_stats_exit(&cfqg->stats); | |
1667 | return kfree(cfqg); | |
1668 | } | |
1669 | ||
1670 | static void cfq_pd_reset_stats(struct blkg_policy_data *pd) | |
1671 | { | |
1672 | struct cfq_group *cfqg = pd_to_cfqg(pd); | |
1673 | ||
1674 | cfqg_stats_reset(&cfqg->stats); | |
1675 | } | |
1676 | ||
1677 | static struct cfq_group *cfq_lookup_cfqg(struct cfq_data *cfqd, | |
1678 | struct blkcg *blkcg) | |
1679 | { | |
1680 | struct blkcg_gq *blkg; | |
1681 | ||
1682 | blkg = blkg_lookup(blkcg, cfqd->queue); | |
1683 | if (likely(blkg)) | |
1684 | return blkg_to_cfqg(blkg); | |
1685 | return NULL; | |
1686 | } | |
1687 | ||
1688 | static void cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) | |
1689 | { | |
1690 | cfqq->cfqg = cfqg; | |
1691 | /* cfqq reference on cfqg */ | |
1692 | cfqg_get(cfqg); | |
1693 | } | |
1694 | ||
1695 | static u64 cfqg_prfill_weight_device(struct seq_file *sf, | |
1696 | struct blkg_policy_data *pd, int off) | |
1697 | { | |
1698 | struct cfq_group *cfqg = pd_to_cfqg(pd); | |
1699 | ||
1700 | if (!cfqg->dev_weight) | |
1701 | return 0; | |
1702 | return __blkg_prfill_u64(sf, pd, cfqg->dev_weight); | |
1703 | } | |
1704 | ||
1705 | static int cfqg_print_weight_device(struct seq_file *sf, void *v) | |
1706 | { | |
1707 | blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), | |
1708 | cfqg_prfill_weight_device, &blkcg_policy_cfq, | |
1709 | 0, false); | |
1710 | return 0; | |
1711 | } | |
1712 | ||
1713 | static u64 cfqg_prfill_leaf_weight_device(struct seq_file *sf, | |
1714 | struct blkg_policy_data *pd, int off) | |
1715 | { | |
1716 | struct cfq_group *cfqg = pd_to_cfqg(pd); | |
1717 | ||
1718 | if (!cfqg->dev_leaf_weight) | |
1719 | return 0; | |
1720 | return __blkg_prfill_u64(sf, pd, cfqg->dev_leaf_weight); | |
1721 | } | |
1722 | ||
1723 | static int cfqg_print_leaf_weight_device(struct seq_file *sf, void *v) | |
1724 | { | |
1725 | blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), | |
1726 | cfqg_prfill_leaf_weight_device, &blkcg_policy_cfq, | |
1727 | 0, false); | |
1728 | return 0; | |
1729 | } | |
1730 | ||
1731 | static int cfq_print_weight(struct seq_file *sf, void *v) | |
1732 | { | |
1733 | struct blkcg *blkcg = css_to_blkcg(seq_css(sf)); | |
1734 | struct cfq_group_data *cgd = blkcg_to_cfqgd(blkcg); | |
1735 | unsigned int val = 0; | |
1736 | ||
1737 | if (cgd) | |
1738 | val = cgd->weight; | |
1739 | ||
1740 | seq_printf(sf, "%u\n", val); | |
1741 | return 0; | |
1742 | } | |
1743 | ||
1744 | static int cfq_print_leaf_weight(struct seq_file *sf, void *v) | |
1745 | { | |
1746 | struct blkcg *blkcg = css_to_blkcg(seq_css(sf)); | |
1747 | struct cfq_group_data *cgd = blkcg_to_cfqgd(blkcg); | |
1748 | unsigned int val = 0; | |
1749 | ||
1750 | if (cgd) | |
1751 | val = cgd->leaf_weight; | |
1752 | ||
1753 | seq_printf(sf, "%u\n", val); | |
1754 | return 0; | |
1755 | } | |
1756 | ||
1757 | static ssize_t __cfqg_set_weight_device(struct kernfs_open_file *of, | |
1758 | char *buf, size_t nbytes, loff_t off, | |
1759 | bool on_dfl, bool is_leaf_weight) | |
1760 | { | |
1761 | unsigned int min = on_dfl ? CGROUP_WEIGHT_MIN : CFQ_WEIGHT_LEGACY_MIN; | |
1762 | unsigned int max = on_dfl ? CGROUP_WEIGHT_MAX : CFQ_WEIGHT_LEGACY_MAX; | |
1763 | struct blkcg *blkcg = css_to_blkcg(of_css(of)); | |
1764 | struct blkg_conf_ctx ctx; | |
1765 | struct cfq_group *cfqg; | |
1766 | struct cfq_group_data *cfqgd; | |
1767 | int ret; | |
1768 | u64 v; | |
1769 | ||
1770 | ret = blkg_conf_prep(blkcg, &blkcg_policy_cfq, buf, &ctx); | |
1771 | if (ret) | |
1772 | return ret; | |
1773 | ||
1774 | if (sscanf(ctx.body, "%llu", &v) == 1) { | |
1775 | /* require "default" on dfl */ | |
1776 | ret = -ERANGE; | |
1777 | if (!v && on_dfl) | |
1778 | goto out_finish; | |
1779 | } else if (!strcmp(strim(ctx.body), "default")) { | |
1780 | v = 0; | |
1781 | } else { | |
1782 | ret = -EINVAL; | |
1783 | goto out_finish; | |
1784 | } | |
1785 | ||
1786 | cfqg = blkg_to_cfqg(ctx.blkg); | |
1787 | cfqgd = blkcg_to_cfqgd(blkcg); | |
1788 | ||
1789 | ret = -ERANGE; | |
1790 | if (!v || (v >= min && v <= max)) { | |
1791 | if (!is_leaf_weight) { | |
1792 | cfqg->dev_weight = v; | |
1793 | cfqg->new_weight = v ?: cfqgd->weight; | |
1794 | } else { | |
1795 | cfqg->dev_leaf_weight = v; | |
1796 | cfqg->new_leaf_weight = v ?: cfqgd->leaf_weight; | |
1797 | } | |
1798 | ret = 0; | |
1799 | } | |
1800 | out_finish: | |
1801 | blkg_conf_finish(&ctx); | |
1802 | return ret ?: nbytes; | |
1803 | } | |
1804 | ||
1805 | static ssize_t cfqg_set_weight_device(struct kernfs_open_file *of, | |
1806 | char *buf, size_t nbytes, loff_t off) | |
1807 | { | |
1808 | return __cfqg_set_weight_device(of, buf, nbytes, off, false, false); | |
1809 | } | |
1810 | ||
1811 | static ssize_t cfqg_set_leaf_weight_device(struct kernfs_open_file *of, | |
1812 | char *buf, size_t nbytes, loff_t off) | |
1813 | { | |
1814 | return __cfqg_set_weight_device(of, buf, nbytes, off, false, true); | |
1815 | } | |
1816 | ||
1817 | static int __cfq_set_weight(struct cgroup_subsys_state *css, u64 val, | |
1818 | bool on_dfl, bool reset_dev, bool is_leaf_weight) | |
1819 | { | |
1820 | unsigned int min = on_dfl ? CGROUP_WEIGHT_MIN : CFQ_WEIGHT_LEGACY_MIN; | |
1821 | unsigned int max = on_dfl ? CGROUP_WEIGHT_MAX : CFQ_WEIGHT_LEGACY_MAX; | |
1822 | struct blkcg *blkcg = css_to_blkcg(css); | |
1823 | struct blkcg_gq *blkg; | |
1824 | struct cfq_group_data *cfqgd; | |
1825 | int ret = 0; | |
1826 | ||
1827 | if (val < min || val > max) | |
1828 | return -ERANGE; | |
1829 | ||
1830 | spin_lock_irq(&blkcg->lock); | |
1831 | cfqgd = blkcg_to_cfqgd(blkcg); | |
1832 | if (!cfqgd) { | |
1833 | ret = -EINVAL; | |
1834 | goto out; | |
1835 | } | |
1836 | ||
1837 | if (!is_leaf_weight) | |
1838 | cfqgd->weight = val; | |
1839 | else | |
1840 | cfqgd->leaf_weight = val; | |
1841 | ||
1842 | hlist_for_each_entry(blkg, &blkcg->blkg_list, blkcg_node) { | |
1843 | struct cfq_group *cfqg = blkg_to_cfqg(blkg); | |
1844 | ||
1845 | if (!cfqg) | |
1846 | continue; | |
1847 | ||
1848 | if (!is_leaf_weight) { | |
1849 | if (reset_dev) | |
1850 | cfqg->dev_weight = 0; | |
1851 | if (!cfqg->dev_weight) | |
1852 | cfqg->new_weight = cfqgd->weight; | |
1853 | } else { | |
1854 | if (reset_dev) | |
1855 | cfqg->dev_leaf_weight = 0; | |
1856 | if (!cfqg->dev_leaf_weight) | |
1857 | cfqg->new_leaf_weight = cfqgd->leaf_weight; | |
1858 | } | |
1859 | } | |
1860 | ||
1861 | out: | |
1862 | spin_unlock_irq(&blkcg->lock); | |
1863 | return ret; | |
1864 | } | |
1865 | ||
1866 | static int cfq_set_weight(struct cgroup_subsys_state *css, struct cftype *cft, | |
1867 | u64 val) | |
1868 | { | |
1869 | return __cfq_set_weight(css, val, false, false, false); | |
1870 | } | |
1871 | ||
1872 | static int cfq_set_leaf_weight(struct cgroup_subsys_state *css, | |
1873 | struct cftype *cft, u64 val) | |
1874 | { | |
1875 | return __cfq_set_weight(css, val, false, false, true); | |
1876 | } | |
1877 | ||
1878 | static int cfqg_print_stat(struct seq_file *sf, void *v) | |
1879 | { | |
1880 | blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), blkg_prfill_stat, | |
1881 | &blkcg_policy_cfq, seq_cft(sf)->private, false); | |
1882 | return 0; | |
1883 | } | |
1884 | ||
1885 | static int cfqg_print_rwstat(struct seq_file *sf, void *v) | |
1886 | { | |
1887 | blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), blkg_prfill_rwstat, | |
1888 | &blkcg_policy_cfq, seq_cft(sf)->private, true); | |
1889 | return 0; | |
1890 | } | |
1891 | ||
1892 | static u64 cfqg_prfill_stat_recursive(struct seq_file *sf, | |
1893 | struct blkg_policy_data *pd, int off) | |
1894 | { | |
1895 | u64 sum = blkg_stat_recursive_sum(pd_to_blkg(pd), | |
1896 | &blkcg_policy_cfq, off); | |
1897 | return __blkg_prfill_u64(sf, pd, sum); | |
1898 | } | |
1899 | ||
1900 | static u64 cfqg_prfill_rwstat_recursive(struct seq_file *sf, | |
1901 | struct blkg_policy_data *pd, int off) | |
1902 | { | |
1903 | struct blkg_rwstat sum = blkg_rwstat_recursive_sum(pd_to_blkg(pd), | |
1904 | &blkcg_policy_cfq, off); | |
1905 | return __blkg_prfill_rwstat(sf, pd, &sum); | |
1906 | } | |
1907 | ||
1908 | static int cfqg_print_stat_recursive(struct seq_file *sf, void *v) | |
1909 | { | |
1910 | blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), | |
1911 | cfqg_prfill_stat_recursive, &blkcg_policy_cfq, | |
1912 | seq_cft(sf)->private, false); | |
1913 | return 0; | |
1914 | } | |
1915 | ||
1916 | static int cfqg_print_rwstat_recursive(struct seq_file *sf, void *v) | |
1917 | { | |
1918 | blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), | |
1919 | cfqg_prfill_rwstat_recursive, &blkcg_policy_cfq, | |
1920 | seq_cft(sf)->private, true); | |
1921 | return 0; | |
1922 | } | |
1923 | ||
1924 | static u64 cfqg_prfill_sectors(struct seq_file *sf, struct blkg_policy_data *pd, | |
1925 | int off) | |
1926 | { | |
1927 | u64 sum = blkg_rwstat_total(&pd->blkg->stat_bytes); | |
1928 | ||
1929 | return __blkg_prfill_u64(sf, pd, sum >> 9); | |
1930 | } | |
1931 | ||
1932 | static int cfqg_print_stat_sectors(struct seq_file *sf, void *v) | |
1933 | { | |
1934 | blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), | |
1935 | cfqg_prfill_sectors, &blkcg_policy_cfq, 0, false); | |
1936 | return 0; | |
1937 | } | |
1938 | ||
1939 | static u64 cfqg_prfill_sectors_recursive(struct seq_file *sf, | |
1940 | struct blkg_policy_data *pd, int off) | |
1941 | { | |
1942 | struct blkg_rwstat tmp = blkg_rwstat_recursive_sum(pd->blkg, NULL, | |
1943 | offsetof(struct blkcg_gq, stat_bytes)); | |
1944 | u64 sum = atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_READ]) + | |
1945 | atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_WRITE]); | |
1946 | ||
1947 | return __blkg_prfill_u64(sf, pd, sum >> 9); | |
1948 | } | |
1949 | ||
1950 | static int cfqg_print_stat_sectors_recursive(struct seq_file *sf, void *v) | |
1951 | { | |
1952 | blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), | |
1953 | cfqg_prfill_sectors_recursive, &blkcg_policy_cfq, 0, | |
1954 | false); | |
1955 | return 0; | |
1956 | } | |
1957 | ||
1958 | #ifdef CONFIG_DEBUG_BLK_CGROUP | |
1959 | static u64 cfqg_prfill_avg_queue_size(struct seq_file *sf, | |
1960 | struct blkg_policy_data *pd, int off) | |
1961 | { | |
1962 | struct cfq_group *cfqg = pd_to_cfqg(pd); | |
1963 | u64 samples = blkg_stat_read(&cfqg->stats.avg_queue_size_samples); | |
1964 | u64 v = 0; | |
1965 | ||
1966 | if (samples) { | |
1967 | v = blkg_stat_read(&cfqg->stats.avg_queue_size_sum); | |
1968 | v = div64_u64(v, samples); | |
1969 | } | |
1970 | __blkg_prfill_u64(sf, pd, v); | |
1971 | return 0; | |
1972 | } | |
1973 | ||
1974 | /* print avg_queue_size */ | |
1975 | static int cfqg_print_avg_queue_size(struct seq_file *sf, void *v) | |
1976 | { | |
1977 | blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), | |
1978 | cfqg_prfill_avg_queue_size, &blkcg_policy_cfq, | |
1979 | 0, false); | |
1980 | return 0; | |
1981 | } | |
1982 | #endif /* CONFIG_DEBUG_BLK_CGROUP */ | |
1983 | ||
1984 | static struct cftype cfq_blkcg_legacy_files[] = { | |
1985 | /* on root, weight is mapped to leaf_weight */ | |
1986 | { | |
1987 | .name = "weight_device", | |
1988 | .flags = CFTYPE_ONLY_ON_ROOT, | |
1989 | .seq_show = cfqg_print_leaf_weight_device, | |
1990 | .write = cfqg_set_leaf_weight_device, | |
1991 | }, | |
1992 | { | |
1993 | .name = "weight", | |
1994 | .flags = CFTYPE_ONLY_ON_ROOT, | |
1995 | .seq_show = cfq_print_leaf_weight, | |
1996 | .write_u64 = cfq_set_leaf_weight, | |
1997 | }, | |
1998 | ||
1999 | /* no such mapping necessary for !roots */ | |
2000 | { | |
2001 | .name = "weight_device", | |
2002 | .flags = CFTYPE_NOT_ON_ROOT, | |
2003 | .seq_show = cfqg_print_weight_device, | |
2004 | .write = cfqg_set_weight_device, | |
2005 | }, | |
2006 | { | |
2007 | .name = "weight", | |
2008 | .flags = CFTYPE_NOT_ON_ROOT, | |
2009 | .seq_show = cfq_print_weight, | |
2010 | .write_u64 = cfq_set_weight, | |
2011 | }, | |
2012 | ||
2013 | { | |
2014 | .name = "leaf_weight_device", | |
2015 | .seq_show = cfqg_print_leaf_weight_device, | |
2016 | .write = cfqg_set_leaf_weight_device, | |
2017 | }, | |
2018 | { | |
2019 | .name = "leaf_weight", | |
2020 | .seq_show = cfq_print_leaf_weight, | |
2021 | .write_u64 = cfq_set_leaf_weight, | |
2022 | }, | |
2023 | ||
2024 | /* statistics, covers only the tasks in the cfqg */ | |
2025 | { | |
2026 | .name = "time", | |
2027 | .private = offsetof(struct cfq_group, stats.time), | |
2028 | .seq_show = cfqg_print_stat, | |
2029 | }, | |
2030 | { | |
2031 | .name = "sectors", | |
2032 | .seq_show = cfqg_print_stat_sectors, | |
2033 | }, | |
2034 | { | |
2035 | .name = "io_service_bytes", | |
2036 | .private = (unsigned long)&blkcg_policy_cfq, | |
2037 | .seq_show = blkg_print_stat_bytes, | |
2038 | }, | |
2039 | { | |
2040 | .name = "io_serviced", | |
2041 | .private = (unsigned long)&blkcg_policy_cfq, | |
2042 | .seq_show = blkg_print_stat_ios, | |
2043 | }, | |
2044 | { | |
2045 | .name = "io_service_time", | |
2046 | .private = offsetof(struct cfq_group, stats.service_time), | |
2047 | .seq_show = cfqg_print_rwstat, | |
2048 | }, | |
2049 | { | |
2050 | .name = "io_wait_time", | |
2051 | .private = offsetof(struct cfq_group, stats.wait_time), | |
2052 | .seq_show = cfqg_print_rwstat, | |
2053 | }, | |
2054 | { | |
2055 | .name = "io_merged", | |
2056 | .private = offsetof(struct cfq_group, stats.merged), | |
2057 | .seq_show = cfqg_print_rwstat, | |
2058 | }, | |
2059 | { | |
2060 | .name = "io_queued", | |
2061 | .private = offsetof(struct cfq_group, stats.queued), | |
2062 | .seq_show = cfqg_print_rwstat, | |
2063 | }, | |
2064 | ||
2065 | /* the same statictics which cover the cfqg and its descendants */ | |
2066 | { | |
2067 | .name = "time_recursive", | |
2068 | .private = offsetof(struct cfq_group, stats.time), | |
2069 | .seq_show = cfqg_print_stat_recursive, | |
2070 | }, | |
2071 | { | |
2072 | .name = "sectors_recursive", | |
2073 | .seq_show = cfqg_print_stat_sectors_recursive, | |
2074 | }, | |
2075 | { | |
2076 | .name = "io_service_bytes_recursive", | |
2077 | .private = (unsigned long)&blkcg_policy_cfq, | |
2078 | .seq_show = blkg_print_stat_bytes_recursive, | |
2079 | }, | |
2080 | { | |
2081 | .name = "io_serviced_recursive", | |
2082 | .private = (unsigned long)&blkcg_policy_cfq, | |
2083 | .seq_show = blkg_print_stat_ios_recursive, | |
2084 | }, | |
2085 | { | |
2086 | .name = "io_service_time_recursive", | |
2087 | .private = offsetof(struct cfq_group, stats.service_time), | |
2088 | .seq_show = cfqg_print_rwstat_recursive, | |
2089 | }, | |
2090 | { | |
2091 | .name = "io_wait_time_recursive", | |
2092 | .private = offsetof(struct cfq_group, stats.wait_time), | |
2093 | .seq_show = cfqg_print_rwstat_recursive, | |
2094 | }, | |
2095 | { | |
2096 | .name = "io_merged_recursive", | |
2097 | .private = offsetof(struct cfq_group, stats.merged), | |
2098 | .seq_show = cfqg_print_rwstat_recursive, | |
2099 | }, | |
2100 | { | |
2101 | .name = "io_queued_recursive", | |
2102 | .private = offsetof(struct cfq_group, stats.queued), | |
2103 | .seq_show = cfqg_print_rwstat_recursive, | |
2104 | }, | |
2105 | #ifdef CONFIG_DEBUG_BLK_CGROUP | |
2106 | { | |
2107 | .name = "avg_queue_size", | |
2108 | .seq_show = cfqg_print_avg_queue_size, | |
2109 | }, | |
2110 | { | |
2111 | .name = "group_wait_time", | |
2112 | .private = offsetof(struct cfq_group, stats.group_wait_time), | |
2113 | .seq_show = cfqg_print_stat, | |
2114 | }, | |
2115 | { | |
2116 | .name = "idle_time", | |
2117 | .private = offsetof(struct cfq_group, stats.idle_time), | |
2118 | .seq_show = cfqg_print_stat, | |
2119 | }, | |
2120 | { | |
2121 | .name = "empty_time", | |
2122 | .private = offsetof(struct cfq_group, stats.empty_time), | |
2123 | .seq_show = cfqg_print_stat, | |
2124 | }, | |
2125 | { | |
2126 | .name = "dequeue", | |
2127 | .private = offsetof(struct cfq_group, stats.dequeue), | |
2128 | .seq_show = cfqg_print_stat, | |
2129 | }, | |
2130 | { | |
2131 | .name = "unaccounted_time", | |
2132 | .private = offsetof(struct cfq_group, stats.unaccounted_time), | |
2133 | .seq_show = cfqg_print_stat, | |
2134 | }, | |
2135 | #endif /* CONFIG_DEBUG_BLK_CGROUP */ | |
2136 | { } /* terminate */ | |
2137 | }; | |
2138 | ||
2139 | static int cfq_print_weight_on_dfl(struct seq_file *sf, void *v) | |
2140 | { | |
2141 | struct blkcg *blkcg = css_to_blkcg(seq_css(sf)); | |
2142 | struct cfq_group_data *cgd = blkcg_to_cfqgd(blkcg); | |
2143 | ||
2144 | seq_printf(sf, "default %u\n", cgd->weight); | |
2145 | blkcg_print_blkgs(sf, blkcg, cfqg_prfill_weight_device, | |
2146 | &blkcg_policy_cfq, 0, false); | |
2147 | return 0; | |
2148 | } | |
2149 | ||
2150 | static ssize_t cfq_set_weight_on_dfl(struct kernfs_open_file *of, | |
2151 | char *buf, size_t nbytes, loff_t off) | |
2152 | { | |
2153 | char *endp; | |
2154 | int ret; | |
2155 | u64 v; | |
2156 | ||
2157 | buf = strim(buf); | |
2158 | ||
2159 | /* "WEIGHT" or "default WEIGHT" sets the default weight */ | |
2160 | v = simple_strtoull(buf, &endp, 0); | |
2161 | if (*endp == '\0' || sscanf(buf, "default %llu", &v) == 1) { | |
2162 | ret = __cfq_set_weight(of_css(of), v, true, false, false); | |
2163 | return ret ?: nbytes; | |
2164 | } | |
2165 | ||
2166 | /* "MAJ:MIN WEIGHT" */ | |
2167 | return __cfqg_set_weight_device(of, buf, nbytes, off, true, false); | |
2168 | } | |
2169 | ||
2170 | static struct cftype cfq_blkcg_files[] = { | |
2171 | { | |
2172 | .name = "weight", | |
2173 | .flags = CFTYPE_NOT_ON_ROOT, | |
2174 | .seq_show = cfq_print_weight_on_dfl, | |
2175 | .write = cfq_set_weight_on_dfl, | |
2176 | }, | |
2177 | { } /* terminate */ | |
2178 | }; | |
2179 | ||
2180 | #else /* GROUP_IOSCHED */ | |
2181 | static struct cfq_group *cfq_lookup_cfqg(struct cfq_data *cfqd, | |
2182 | struct blkcg *blkcg) | |
2183 | { | |
2184 | return cfqd->root_group; | |
2185 | } | |
2186 | ||
2187 | static inline void | |
2188 | cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) { | |
2189 | cfqq->cfqg = cfqg; | |
2190 | } | |
2191 | ||
2192 | #endif /* GROUP_IOSCHED */ | |
2193 | ||
2194 | /* | |
2195 | * The cfqd->service_trees holds all pending cfq_queue's that have | |
2196 | * requests waiting to be processed. It is sorted in the order that | |
2197 | * we will service the queues. | |
2198 | */ | |
2199 | static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
2200 | bool add_front) | |
2201 | { | |
2202 | struct rb_node **p, *parent; | |
2203 | struct cfq_queue *__cfqq; | |
2204 | u64 rb_key; | |
2205 | struct cfq_rb_root *st; | |
2206 | bool leftmost = true; | |
2207 | int new_cfqq = 1; | |
2208 | u64 now = ktime_get_ns(); | |
2209 | ||
2210 | st = st_for(cfqq->cfqg, cfqq_class(cfqq), cfqq_type(cfqq)); | |
2211 | if (cfq_class_idle(cfqq)) { | |
2212 | rb_key = CFQ_IDLE_DELAY; | |
2213 | parent = st->rb_rightmost; | |
2214 | if (parent && parent != &cfqq->rb_node) { | |
2215 | __cfqq = rb_entry(parent, struct cfq_queue, rb_node); | |
2216 | rb_key += __cfqq->rb_key; | |
2217 | } else | |
2218 | rb_key += now; | |
2219 | } else if (!add_front) { | |
2220 | /* | |
2221 | * Get our rb key offset. Subtract any residual slice | |
2222 | * value carried from last service. A negative resid | |
2223 | * count indicates slice overrun, and this should position | |
2224 | * the next service time further away in the tree. | |
2225 | */ | |
2226 | rb_key = cfq_slice_offset(cfqd, cfqq) + now; | |
2227 | rb_key -= cfqq->slice_resid; | |
2228 | cfqq->slice_resid = 0; | |
2229 | } else { | |
2230 | rb_key = -NSEC_PER_SEC; | |
2231 | __cfqq = cfq_rb_first(st); | |
2232 | rb_key += __cfqq ? __cfqq->rb_key : now; | |
2233 | } | |
2234 | ||
2235 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) { | |
2236 | new_cfqq = 0; | |
2237 | /* | |
2238 | * same position, nothing more to do | |
2239 | */ | |
2240 | if (rb_key == cfqq->rb_key && cfqq->service_tree == st) | |
2241 | return; | |
2242 | ||
2243 | cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree); | |
2244 | cfqq->service_tree = NULL; | |
2245 | } | |
2246 | ||
2247 | parent = NULL; | |
2248 | cfqq->service_tree = st; | |
2249 | p = &st->rb.rb_root.rb_node; | |
2250 | while (*p) { | |
2251 | parent = *p; | |
2252 | __cfqq = rb_entry(parent, struct cfq_queue, rb_node); | |
2253 | ||
2254 | /* | |
2255 | * sort by key, that represents service time. | |
2256 | */ | |
2257 | if (rb_key < __cfqq->rb_key) | |
2258 | p = &parent->rb_left; | |
2259 | else { | |
2260 | p = &parent->rb_right; | |
2261 | leftmost = false; | |
2262 | } | |
2263 | } | |
2264 | ||
2265 | cfqq->rb_key = rb_key; | |
2266 | rb_link_node(&cfqq->rb_node, parent, p); | |
2267 | rb_insert_color_cached(&cfqq->rb_node, &st->rb, leftmost); | |
2268 | st->count++; | |
2269 | if (add_front || !new_cfqq) | |
2270 | return; | |
2271 | cfq_group_notify_queue_add(cfqd, cfqq->cfqg); | |
2272 | } | |
2273 | ||
2274 | static struct cfq_queue * | |
2275 | cfq_prio_tree_lookup(struct cfq_data *cfqd, struct rb_root *root, | |
2276 | sector_t sector, struct rb_node **ret_parent, | |
2277 | struct rb_node ***rb_link) | |
2278 | { | |
2279 | struct rb_node **p, *parent; | |
2280 | struct cfq_queue *cfqq = NULL; | |
2281 | ||
2282 | parent = NULL; | |
2283 | p = &root->rb_node; | |
2284 | while (*p) { | |
2285 | struct rb_node **n; | |
2286 | ||
2287 | parent = *p; | |
2288 | cfqq = rb_entry(parent, struct cfq_queue, p_node); | |
2289 | ||
2290 | /* | |
2291 | * Sort strictly based on sector. Smallest to the left, | |
2292 | * largest to the right. | |
2293 | */ | |
2294 | if (sector > blk_rq_pos(cfqq->next_rq)) | |
2295 | n = &(*p)->rb_right; | |
2296 | else if (sector < blk_rq_pos(cfqq->next_rq)) | |
2297 | n = &(*p)->rb_left; | |
2298 | else | |
2299 | break; | |
2300 | p = n; | |
2301 | cfqq = NULL; | |
2302 | } | |
2303 | ||
2304 | *ret_parent = parent; | |
2305 | if (rb_link) | |
2306 | *rb_link = p; | |
2307 | return cfqq; | |
2308 | } | |
2309 | ||
2310 | static void cfq_prio_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
2311 | { | |
2312 | struct rb_node **p, *parent; | |
2313 | struct cfq_queue *__cfqq; | |
2314 | ||
2315 | if (cfqq->p_root) { | |
2316 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
2317 | cfqq->p_root = NULL; | |
2318 | } | |
2319 | ||
2320 | if (cfq_class_idle(cfqq)) | |
2321 | return; | |
2322 | if (!cfqq->next_rq) | |
2323 | return; | |
2324 | ||
2325 | cfqq->p_root = &cfqd->prio_trees[cfqq->org_ioprio]; | |
2326 | __cfqq = cfq_prio_tree_lookup(cfqd, cfqq->p_root, | |
2327 | blk_rq_pos(cfqq->next_rq), &parent, &p); | |
2328 | if (!__cfqq) { | |
2329 | rb_link_node(&cfqq->p_node, parent, p); | |
2330 | rb_insert_color(&cfqq->p_node, cfqq->p_root); | |
2331 | } else | |
2332 | cfqq->p_root = NULL; | |
2333 | } | |
2334 | ||
2335 | /* | |
2336 | * Update cfqq's position in the service tree. | |
2337 | */ | |
2338 | static void cfq_resort_rr_list(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
2339 | { | |
2340 | /* | |
2341 | * Resorting requires the cfqq to be on the RR list already. | |
2342 | */ | |
2343 | if (cfq_cfqq_on_rr(cfqq)) { | |
2344 | cfq_service_tree_add(cfqd, cfqq, 0); | |
2345 | cfq_prio_tree_add(cfqd, cfqq); | |
2346 | } | |
2347 | } | |
2348 | ||
2349 | /* | |
2350 | * add to busy list of queues for service, trying to be fair in ordering | |
2351 | * the pending list according to last request service | |
2352 | */ | |
2353 | static void cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
2354 | { | |
2355 | cfq_log_cfqq(cfqd, cfqq, "add_to_rr"); | |
2356 | BUG_ON(cfq_cfqq_on_rr(cfqq)); | |
2357 | cfq_mark_cfqq_on_rr(cfqq); | |
2358 | cfqd->busy_queues++; | |
2359 | if (cfq_cfqq_sync(cfqq)) | |
2360 | cfqd->busy_sync_queues++; | |
2361 | ||
2362 | cfq_resort_rr_list(cfqd, cfqq); | |
2363 | } | |
2364 | ||
2365 | /* | |
2366 | * Called when the cfqq no longer has requests pending, remove it from | |
2367 | * the service tree. | |
2368 | */ | |
2369 | static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
2370 | { | |
2371 | cfq_log_cfqq(cfqd, cfqq, "del_from_rr"); | |
2372 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); | |
2373 | cfq_clear_cfqq_on_rr(cfqq); | |
2374 | ||
2375 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) { | |
2376 | cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree); | |
2377 | cfqq->service_tree = NULL; | |
2378 | } | |
2379 | if (cfqq->p_root) { | |
2380 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
2381 | cfqq->p_root = NULL; | |
2382 | } | |
2383 | ||
2384 | cfq_group_notify_queue_del(cfqd, cfqq->cfqg); | |
2385 | BUG_ON(!cfqd->busy_queues); | |
2386 | cfqd->busy_queues--; | |
2387 | if (cfq_cfqq_sync(cfqq)) | |
2388 | cfqd->busy_sync_queues--; | |
2389 | } | |
2390 | ||
2391 | /* | |
2392 | * rb tree support functions | |
2393 | */ | |
2394 | static void cfq_del_rq_rb(struct request *rq) | |
2395 | { | |
2396 | struct cfq_queue *cfqq = RQ_CFQQ(rq); | |
2397 | const int sync = rq_is_sync(rq); | |
2398 | ||
2399 | BUG_ON(!cfqq->queued[sync]); | |
2400 | cfqq->queued[sync]--; | |
2401 | ||
2402 | elv_rb_del(&cfqq->sort_list, rq); | |
2403 | ||
2404 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) { | |
2405 | /* | |
2406 | * Queue will be deleted from service tree when we actually | |
2407 | * expire it later. Right now just remove it from prio tree | |
2408 | * as it is empty. | |
2409 | */ | |
2410 | if (cfqq->p_root) { | |
2411 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
2412 | cfqq->p_root = NULL; | |
2413 | } | |
2414 | } | |
2415 | } | |
2416 | ||
2417 | static void cfq_add_rq_rb(struct request *rq) | |
2418 | { | |
2419 | struct cfq_queue *cfqq = RQ_CFQQ(rq); | |
2420 | struct cfq_data *cfqd = cfqq->cfqd; | |
2421 | struct request *prev; | |
2422 | ||
2423 | cfqq->queued[rq_is_sync(rq)]++; | |
2424 | ||
2425 | elv_rb_add(&cfqq->sort_list, rq); | |
2426 | ||
2427 | if (!cfq_cfqq_on_rr(cfqq)) | |
2428 | cfq_add_cfqq_rr(cfqd, cfqq); | |
2429 | ||
2430 | /* | |
2431 | * check if this request is a better next-serve candidate | |
2432 | */ | |
2433 | prev = cfqq->next_rq; | |
2434 | cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq, cfqd->last_position); | |
2435 | ||
2436 | /* | |
2437 | * adjust priority tree position, if ->next_rq changes | |
2438 | */ | |
2439 | if (prev != cfqq->next_rq) | |
2440 | cfq_prio_tree_add(cfqd, cfqq); | |
2441 | ||
2442 | BUG_ON(!cfqq->next_rq); | |
2443 | } | |
2444 | ||
2445 | static void cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq) | |
2446 | { | |
2447 | elv_rb_del(&cfqq->sort_list, rq); | |
2448 | cfqq->queued[rq_is_sync(rq)]--; | |
2449 | cfqg_stats_update_io_remove(RQ_CFQG(rq), rq->cmd_flags); | |
2450 | cfq_add_rq_rb(rq); | |
2451 | cfqg_stats_update_io_add(RQ_CFQG(rq), cfqq->cfqd->serving_group, | |
2452 | rq->cmd_flags); | |
2453 | } | |
2454 | ||
2455 | static struct request * | |
2456 | cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio) | |
2457 | { | |
2458 | struct task_struct *tsk = current; | |
2459 | struct cfq_io_cq *cic; | |
2460 | struct cfq_queue *cfqq; | |
2461 | ||
2462 | cic = cfq_cic_lookup(cfqd, tsk->io_context); | |
2463 | if (!cic) | |
2464 | return NULL; | |
2465 | ||
2466 | cfqq = cic_to_cfqq(cic, op_is_sync(bio->bi_opf)); | |
2467 | if (cfqq) | |
2468 | return elv_rb_find(&cfqq->sort_list, bio_end_sector(bio)); | |
2469 | ||
2470 | return NULL; | |
2471 | } | |
2472 | ||
2473 | static void cfq_activate_request(struct request_queue *q, struct request *rq) | |
2474 | { | |
2475 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
2476 | ||
2477 | cfqd->rq_in_driver++; | |
2478 | cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "activate rq, drv=%d", | |
2479 | cfqd->rq_in_driver); | |
2480 | ||
2481 | cfqd->last_position = blk_rq_pos(rq) + blk_rq_sectors(rq); | |
2482 | } | |
2483 | ||
2484 | static void cfq_deactivate_request(struct request_queue *q, struct request *rq) | |
2485 | { | |
2486 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
2487 | ||
2488 | WARN_ON(!cfqd->rq_in_driver); | |
2489 | cfqd->rq_in_driver--; | |
2490 | cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "deactivate rq, drv=%d", | |
2491 | cfqd->rq_in_driver); | |
2492 | } | |
2493 | ||
2494 | static void cfq_remove_request(struct request *rq) | |
2495 | { | |
2496 | struct cfq_queue *cfqq = RQ_CFQQ(rq); | |
2497 | ||
2498 | if (cfqq->next_rq == rq) | |
2499 | cfqq->next_rq = cfq_find_next_rq(cfqq->cfqd, cfqq, rq); | |
2500 | ||
2501 | list_del_init(&rq->queuelist); | |
2502 | cfq_del_rq_rb(rq); | |
2503 | ||
2504 | cfqq->cfqd->rq_queued--; | |
2505 | cfqg_stats_update_io_remove(RQ_CFQG(rq), rq->cmd_flags); | |
2506 | if (rq->cmd_flags & REQ_PRIO) { | |
2507 | WARN_ON(!cfqq->prio_pending); | |
2508 | cfqq->prio_pending--; | |
2509 | } | |
2510 | } | |
2511 | ||
2512 | static enum elv_merge cfq_merge(struct request_queue *q, struct request **req, | |
2513 | struct bio *bio) | |
2514 | { | |
2515 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
2516 | struct request *__rq; | |
2517 | ||
2518 | __rq = cfq_find_rq_fmerge(cfqd, bio); | |
2519 | if (__rq && elv_bio_merge_ok(__rq, bio)) { | |
2520 | *req = __rq; | |
2521 | return ELEVATOR_FRONT_MERGE; | |
2522 | } | |
2523 | ||
2524 | return ELEVATOR_NO_MERGE; | |
2525 | } | |
2526 | ||
2527 | static void cfq_merged_request(struct request_queue *q, struct request *req, | |
2528 | enum elv_merge type) | |
2529 | { | |
2530 | if (type == ELEVATOR_FRONT_MERGE) { | |
2531 | struct cfq_queue *cfqq = RQ_CFQQ(req); | |
2532 | ||
2533 | cfq_reposition_rq_rb(cfqq, req); | |
2534 | } | |
2535 | } | |
2536 | ||
2537 | static void cfq_bio_merged(struct request_queue *q, struct request *req, | |
2538 | struct bio *bio) | |
2539 | { | |
2540 | cfqg_stats_update_io_merged(RQ_CFQG(req), bio->bi_opf); | |
2541 | } | |
2542 | ||
2543 | static void | |
2544 | cfq_merged_requests(struct request_queue *q, struct request *rq, | |
2545 | struct request *next) | |
2546 | { | |
2547 | struct cfq_queue *cfqq = RQ_CFQQ(rq); | |
2548 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
2549 | ||
2550 | /* | |
2551 | * reposition in fifo if next is older than rq | |
2552 | */ | |
2553 | if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && | |
2554 | next->fifo_time < rq->fifo_time && | |
2555 | cfqq == RQ_CFQQ(next)) { | |
2556 | list_move(&rq->queuelist, &next->queuelist); | |
2557 | rq->fifo_time = next->fifo_time; | |
2558 | } | |
2559 | ||
2560 | if (cfqq->next_rq == next) | |
2561 | cfqq->next_rq = rq; | |
2562 | cfq_remove_request(next); | |
2563 | cfqg_stats_update_io_merged(RQ_CFQG(rq), next->cmd_flags); | |
2564 | ||
2565 | cfqq = RQ_CFQQ(next); | |
2566 | /* | |
2567 | * all requests of this queue are merged to other queues, delete it | |
2568 | * from the service tree. If it's the active_queue, | |
2569 | * cfq_dispatch_requests() will choose to expire it or do idle | |
2570 | */ | |
2571 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list) && | |
2572 | cfqq != cfqd->active_queue) | |
2573 | cfq_del_cfqq_rr(cfqd, cfqq); | |
2574 | } | |
2575 | ||
2576 | static int cfq_allow_bio_merge(struct request_queue *q, struct request *rq, | |
2577 | struct bio *bio) | |
2578 | { | |
2579 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
2580 | bool is_sync = op_is_sync(bio->bi_opf); | |
2581 | struct cfq_io_cq *cic; | |
2582 | struct cfq_queue *cfqq; | |
2583 | ||
2584 | /* | |
2585 | * Disallow merge of a sync bio into an async request. | |
2586 | */ | |
2587 | if (is_sync && !rq_is_sync(rq)) | |
2588 | return false; | |
2589 | ||
2590 | /* | |
2591 | * Lookup the cfqq that this bio will be queued with and allow | |
2592 | * merge only if rq is queued there. | |
2593 | */ | |
2594 | cic = cfq_cic_lookup(cfqd, current->io_context); | |
2595 | if (!cic) | |
2596 | return false; | |
2597 | ||
2598 | cfqq = cic_to_cfqq(cic, is_sync); | |
2599 | return cfqq == RQ_CFQQ(rq); | |
2600 | } | |
2601 | ||
2602 | static int cfq_allow_rq_merge(struct request_queue *q, struct request *rq, | |
2603 | struct request *next) | |
2604 | { | |
2605 | return RQ_CFQQ(rq) == RQ_CFQQ(next); | |
2606 | } | |
2607 | ||
2608 | static inline void cfq_del_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
2609 | { | |
2610 | hrtimer_try_to_cancel(&cfqd->idle_slice_timer); | |
2611 | cfqg_stats_update_idle_time(cfqq->cfqg); | |
2612 | } | |
2613 | ||
2614 | static void __cfq_set_active_queue(struct cfq_data *cfqd, | |
2615 | struct cfq_queue *cfqq) | |
2616 | { | |
2617 | if (cfqq) { | |
2618 | cfq_log_cfqq(cfqd, cfqq, "set_active wl_class:%d wl_type:%d", | |
2619 | cfqd->serving_wl_class, cfqd->serving_wl_type); | |
2620 | cfqg_stats_update_avg_queue_size(cfqq->cfqg); | |
2621 | cfqq->slice_start = 0; | |
2622 | cfqq->dispatch_start = ktime_get_ns(); | |
2623 | cfqq->allocated_slice = 0; | |
2624 | cfqq->slice_end = 0; | |
2625 | cfqq->slice_dispatch = 0; | |
2626 | cfqq->nr_sectors = 0; | |
2627 | ||
2628 | cfq_clear_cfqq_wait_request(cfqq); | |
2629 | cfq_clear_cfqq_must_dispatch(cfqq); | |
2630 | cfq_clear_cfqq_must_alloc_slice(cfqq); | |
2631 | cfq_clear_cfqq_fifo_expire(cfqq); | |
2632 | cfq_mark_cfqq_slice_new(cfqq); | |
2633 | ||
2634 | cfq_del_timer(cfqd, cfqq); | |
2635 | } | |
2636 | ||
2637 | cfqd->active_queue = cfqq; | |
2638 | } | |
2639 | ||
2640 | /* | |
2641 | * current cfqq expired its slice (or was too idle), select new one | |
2642 | */ | |
2643 | static void | |
2644 | __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
2645 | bool timed_out) | |
2646 | { | |
2647 | cfq_log_cfqq(cfqd, cfqq, "slice expired t=%d", timed_out); | |
2648 | ||
2649 | if (cfq_cfqq_wait_request(cfqq)) | |
2650 | cfq_del_timer(cfqd, cfqq); | |
2651 | ||
2652 | cfq_clear_cfqq_wait_request(cfqq); | |
2653 | cfq_clear_cfqq_wait_busy(cfqq); | |
2654 | ||
2655 | /* | |
2656 | * If this cfqq is shared between multiple processes, check to | |
2657 | * make sure that those processes are still issuing I/Os within | |
2658 | * the mean seek distance. If not, it may be time to break the | |
2659 | * queues apart again. | |
2660 | */ | |
2661 | if (cfq_cfqq_coop(cfqq) && CFQQ_SEEKY(cfqq)) | |
2662 | cfq_mark_cfqq_split_coop(cfqq); | |
2663 | ||
2664 | /* | |
2665 | * store what was left of this slice, if the queue idled/timed out | |
2666 | */ | |
2667 | if (timed_out) { | |
2668 | if (cfq_cfqq_slice_new(cfqq)) | |
2669 | cfqq->slice_resid = cfq_scaled_cfqq_slice(cfqd, cfqq); | |
2670 | else | |
2671 | cfqq->slice_resid = cfqq->slice_end - ktime_get_ns(); | |
2672 | cfq_log_cfqq(cfqd, cfqq, "resid=%lld", cfqq->slice_resid); | |
2673 | } | |
2674 | ||
2675 | cfq_group_served(cfqd, cfqq->cfqg, cfqq); | |
2676 | ||
2677 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) | |
2678 | cfq_del_cfqq_rr(cfqd, cfqq); | |
2679 | ||
2680 | cfq_resort_rr_list(cfqd, cfqq); | |
2681 | ||
2682 | if (cfqq == cfqd->active_queue) | |
2683 | cfqd->active_queue = NULL; | |
2684 | ||
2685 | if (cfqd->active_cic) { | |
2686 | put_io_context(cfqd->active_cic->icq.ioc); | |
2687 | cfqd->active_cic = NULL; | |
2688 | } | |
2689 | } | |
2690 | ||
2691 | static inline void cfq_slice_expired(struct cfq_data *cfqd, bool timed_out) | |
2692 | { | |
2693 | struct cfq_queue *cfqq = cfqd->active_queue; | |
2694 | ||
2695 | if (cfqq) | |
2696 | __cfq_slice_expired(cfqd, cfqq, timed_out); | |
2697 | } | |
2698 | ||
2699 | /* | |
2700 | * Get next queue for service. Unless we have a queue preemption, | |
2701 | * we'll simply select the first cfqq in the service tree. | |
2702 | */ | |
2703 | static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd) | |
2704 | { | |
2705 | struct cfq_rb_root *st = st_for(cfqd->serving_group, | |
2706 | cfqd->serving_wl_class, cfqd->serving_wl_type); | |
2707 | ||
2708 | if (!cfqd->rq_queued) | |
2709 | return NULL; | |
2710 | ||
2711 | /* There is nothing to dispatch */ | |
2712 | if (!st) | |
2713 | return NULL; | |
2714 | if (RB_EMPTY_ROOT(&st->rb.rb_root)) | |
2715 | return NULL; | |
2716 | return cfq_rb_first(st); | |
2717 | } | |
2718 | ||
2719 | static struct cfq_queue *cfq_get_next_queue_forced(struct cfq_data *cfqd) | |
2720 | { | |
2721 | struct cfq_group *cfqg; | |
2722 | struct cfq_queue *cfqq; | |
2723 | int i, j; | |
2724 | struct cfq_rb_root *st; | |
2725 | ||
2726 | if (!cfqd->rq_queued) | |
2727 | return NULL; | |
2728 | ||
2729 | cfqg = cfq_get_next_cfqg(cfqd); | |
2730 | if (!cfqg) | |
2731 | return NULL; | |
2732 | ||
2733 | for_each_cfqg_st(cfqg, i, j, st) { | |
2734 | cfqq = cfq_rb_first(st); | |
2735 | if (cfqq) | |
2736 | return cfqq; | |
2737 | } | |
2738 | return NULL; | |
2739 | } | |
2740 | ||
2741 | /* | |
2742 | * Get and set a new active queue for service. | |
2743 | */ | |
2744 | static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd, | |
2745 | struct cfq_queue *cfqq) | |
2746 | { | |
2747 | if (!cfqq) | |
2748 | cfqq = cfq_get_next_queue(cfqd); | |
2749 | ||
2750 | __cfq_set_active_queue(cfqd, cfqq); | |
2751 | return cfqq; | |
2752 | } | |
2753 | ||
2754 | static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd, | |
2755 | struct request *rq) | |
2756 | { | |
2757 | if (blk_rq_pos(rq) >= cfqd->last_position) | |
2758 | return blk_rq_pos(rq) - cfqd->last_position; | |
2759 | else | |
2760 | return cfqd->last_position - blk_rq_pos(rq); | |
2761 | } | |
2762 | ||
2763 | static inline int cfq_rq_close(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
2764 | struct request *rq) | |
2765 | { | |
2766 | return cfq_dist_from_last(cfqd, rq) <= CFQQ_CLOSE_THR; | |
2767 | } | |
2768 | ||
2769 | static struct cfq_queue *cfqq_close(struct cfq_data *cfqd, | |
2770 | struct cfq_queue *cur_cfqq) | |
2771 | { | |
2772 | struct rb_root *root = &cfqd->prio_trees[cur_cfqq->org_ioprio]; | |
2773 | struct rb_node *parent, *node; | |
2774 | struct cfq_queue *__cfqq; | |
2775 | sector_t sector = cfqd->last_position; | |
2776 | ||
2777 | if (RB_EMPTY_ROOT(root)) | |
2778 | return NULL; | |
2779 | ||
2780 | /* | |
2781 | * First, if we find a request starting at the end of the last | |
2782 | * request, choose it. | |
2783 | */ | |
2784 | __cfqq = cfq_prio_tree_lookup(cfqd, root, sector, &parent, NULL); | |
2785 | if (__cfqq) | |
2786 | return __cfqq; | |
2787 | ||
2788 | /* | |
2789 | * If the exact sector wasn't found, the parent of the NULL leaf | |
2790 | * will contain the closest sector. | |
2791 | */ | |
2792 | __cfqq = rb_entry(parent, struct cfq_queue, p_node); | |
2793 | if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq)) | |
2794 | return __cfqq; | |
2795 | ||
2796 | if (blk_rq_pos(__cfqq->next_rq) < sector) | |
2797 | node = rb_next(&__cfqq->p_node); | |
2798 | else | |
2799 | node = rb_prev(&__cfqq->p_node); | |
2800 | if (!node) | |
2801 | return NULL; | |
2802 | ||
2803 | __cfqq = rb_entry(node, struct cfq_queue, p_node); | |
2804 | if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq)) | |
2805 | return __cfqq; | |
2806 | ||
2807 | return NULL; | |
2808 | } | |
2809 | ||
2810 | /* | |
2811 | * cfqd - obvious | |
2812 | * cur_cfqq - passed in so that we don't decide that the current queue is | |
2813 | * closely cooperating with itself. | |
2814 | * | |
2815 | * So, basically we're assuming that that cur_cfqq has dispatched at least | |
2816 | * one request, and that cfqd->last_position reflects a position on the disk | |
2817 | * associated with the I/O issued by cur_cfqq. I'm not sure this is a valid | |
2818 | * assumption. | |
2819 | */ | |
2820 | static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd, | |
2821 | struct cfq_queue *cur_cfqq) | |
2822 | { | |
2823 | struct cfq_queue *cfqq; | |
2824 | ||
2825 | if (cfq_class_idle(cur_cfqq)) | |
2826 | return NULL; | |
2827 | if (!cfq_cfqq_sync(cur_cfqq)) | |
2828 | return NULL; | |
2829 | if (CFQQ_SEEKY(cur_cfqq)) | |
2830 | return NULL; | |
2831 | ||
2832 | /* | |
2833 | * Don't search priority tree if it's the only queue in the group. | |
2834 | */ | |
2835 | if (cur_cfqq->cfqg->nr_cfqq == 1) | |
2836 | return NULL; | |
2837 | ||
2838 | /* | |
2839 | * We should notice if some of the queues are cooperating, eg | |
2840 | * working closely on the same area of the disk. In that case, | |
2841 | * we can group them together and don't waste time idling. | |
2842 | */ | |
2843 | cfqq = cfqq_close(cfqd, cur_cfqq); | |
2844 | if (!cfqq) | |
2845 | return NULL; | |
2846 | ||
2847 | /* If new queue belongs to different cfq_group, don't choose it */ | |
2848 | if (cur_cfqq->cfqg != cfqq->cfqg) | |
2849 | return NULL; | |
2850 | ||
2851 | /* | |
2852 | * It only makes sense to merge sync queues. | |
2853 | */ | |
2854 | if (!cfq_cfqq_sync(cfqq)) | |
2855 | return NULL; | |
2856 | if (CFQQ_SEEKY(cfqq)) | |
2857 | return NULL; | |
2858 | ||
2859 | /* | |
2860 | * Do not merge queues of different priority classes | |
2861 | */ | |
2862 | if (cfq_class_rt(cfqq) != cfq_class_rt(cur_cfqq)) | |
2863 | return NULL; | |
2864 | ||
2865 | return cfqq; | |
2866 | } | |
2867 | ||
2868 | /* | |
2869 | * Determine whether we should enforce idle window for this queue. | |
2870 | */ | |
2871 | ||
2872 | static bool cfq_should_idle(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
2873 | { | |
2874 | enum wl_class_t wl_class = cfqq_class(cfqq); | |
2875 | struct cfq_rb_root *st = cfqq->service_tree; | |
2876 | ||
2877 | BUG_ON(!st); | |
2878 | BUG_ON(!st->count); | |
2879 | ||
2880 | if (!cfqd->cfq_slice_idle) | |
2881 | return false; | |
2882 | ||
2883 | /* We never do for idle class queues. */ | |
2884 | if (wl_class == IDLE_WORKLOAD) | |
2885 | return false; | |
2886 | ||
2887 | /* We do for queues that were marked with idle window flag. */ | |
2888 | if (cfq_cfqq_idle_window(cfqq) && | |
2889 | !(blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag)) | |
2890 | return true; | |
2891 | ||
2892 | /* | |
2893 | * Otherwise, we do only if they are the last ones | |
2894 | * in their service tree. | |
2895 | */ | |
2896 | if (st->count == 1 && cfq_cfqq_sync(cfqq) && | |
2897 | !cfq_io_thinktime_big(cfqd, &st->ttime, false)) | |
2898 | return true; | |
2899 | cfq_log_cfqq(cfqd, cfqq, "Not idling. st->count:%d", st->count); | |
2900 | return false; | |
2901 | } | |
2902 | ||
2903 | static void cfq_arm_slice_timer(struct cfq_data *cfqd) | |
2904 | { | |
2905 | struct cfq_queue *cfqq = cfqd->active_queue; | |
2906 | struct cfq_rb_root *st = cfqq->service_tree; | |
2907 | struct cfq_io_cq *cic; | |
2908 | u64 sl, group_idle = 0; | |
2909 | u64 now = ktime_get_ns(); | |
2910 | ||
2911 | /* | |
2912 | * SSD device without seek penalty, disable idling. But only do so | |
2913 | * for devices that support queuing, otherwise we still have a problem | |
2914 | * with sync vs async workloads. | |
2915 | */ | |
2916 | if (blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag && | |
2917 | !cfqd->cfq_group_idle) | |
2918 | return; | |
2919 | ||
2920 | WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list)); | |
2921 | WARN_ON(cfq_cfqq_slice_new(cfqq)); | |
2922 | ||
2923 | /* | |
2924 | * idle is disabled, either manually or by past process history | |
2925 | */ | |
2926 | if (!cfq_should_idle(cfqd, cfqq)) { | |
2927 | /* no queue idling. Check for group idling */ | |
2928 | if (cfqd->cfq_group_idle) | |
2929 | group_idle = cfqd->cfq_group_idle; | |
2930 | else | |
2931 | return; | |
2932 | } | |
2933 | ||
2934 | /* | |
2935 | * still active requests from this queue, don't idle | |
2936 | */ | |
2937 | if (cfqq->dispatched) | |
2938 | return; | |
2939 | ||
2940 | /* | |
2941 | * task has exited, don't wait | |
2942 | */ | |
2943 | cic = cfqd->active_cic; | |
2944 | if (!cic || !atomic_read(&cic->icq.ioc->active_ref)) | |
2945 | return; | |
2946 | ||
2947 | /* | |
2948 | * If our average think time is larger than the remaining time | |
2949 | * slice, then don't idle. This avoids overrunning the allotted | |
2950 | * time slice. | |
2951 | */ | |
2952 | if (sample_valid(cic->ttime.ttime_samples) && | |
2953 | (cfqq->slice_end - now < cic->ttime.ttime_mean)) { | |
2954 | cfq_log_cfqq(cfqd, cfqq, "Not idling. think_time:%llu", | |
2955 | cic->ttime.ttime_mean); | |
2956 | return; | |
2957 | } | |
2958 | ||
2959 | /* | |
2960 | * There are other queues in the group or this is the only group and | |
2961 | * it has too big thinktime, don't do group idle. | |
2962 | */ | |
2963 | if (group_idle && | |
2964 | (cfqq->cfqg->nr_cfqq > 1 || | |
2965 | cfq_io_thinktime_big(cfqd, &st->ttime, true))) | |
2966 | return; | |
2967 | ||
2968 | cfq_mark_cfqq_wait_request(cfqq); | |
2969 | ||
2970 | if (group_idle) | |
2971 | sl = cfqd->cfq_group_idle; | |
2972 | else | |
2973 | sl = cfqd->cfq_slice_idle; | |
2974 | ||
2975 | hrtimer_start(&cfqd->idle_slice_timer, ns_to_ktime(sl), | |
2976 | HRTIMER_MODE_REL); | |
2977 | cfqg_stats_set_start_idle_time(cfqq->cfqg); | |
2978 | cfq_log_cfqq(cfqd, cfqq, "arm_idle: %llu group_idle: %d", sl, | |
2979 | group_idle ? 1 : 0); | |
2980 | } | |
2981 | ||
2982 | /* | |
2983 | * Move request from internal lists to the request queue dispatch list. | |
2984 | */ | |
2985 | static void cfq_dispatch_insert(struct request_queue *q, struct request *rq) | |
2986 | { | |
2987 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
2988 | struct cfq_queue *cfqq = RQ_CFQQ(rq); | |
2989 | ||
2990 | cfq_log_cfqq(cfqd, cfqq, "dispatch_insert"); | |
2991 | ||
2992 | cfqq->next_rq = cfq_find_next_rq(cfqd, cfqq, rq); | |
2993 | cfq_remove_request(rq); | |
2994 | cfqq->dispatched++; | |
2995 | (RQ_CFQG(rq))->dispatched++; | |
2996 | elv_dispatch_sort(q, rq); | |
2997 | ||
2998 | cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]++; | |
2999 | cfqq->nr_sectors += blk_rq_sectors(rq); | |
3000 | } | |
3001 | ||
3002 | /* | |
3003 | * return expired entry, or NULL to just start from scratch in rbtree | |
3004 | */ | |
3005 | static struct request *cfq_check_fifo(struct cfq_queue *cfqq) | |
3006 | { | |
3007 | struct request *rq = NULL; | |
3008 | ||
3009 | if (cfq_cfqq_fifo_expire(cfqq)) | |
3010 | return NULL; | |
3011 | ||
3012 | cfq_mark_cfqq_fifo_expire(cfqq); | |
3013 | ||
3014 | if (list_empty(&cfqq->fifo)) | |
3015 | return NULL; | |
3016 | ||
3017 | rq = rq_entry_fifo(cfqq->fifo.next); | |
3018 | if (ktime_get_ns() < rq->fifo_time) | |
3019 | rq = NULL; | |
3020 | ||
3021 | return rq; | |
3022 | } | |
3023 | ||
3024 | static inline int | |
3025 | cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
3026 | { | |
3027 | const int base_rq = cfqd->cfq_slice_async_rq; | |
3028 | ||
3029 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); | |
3030 | ||
3031 | return 2 * base_rq * (IOPRIO_BE_NR - cfqq->ioprio); | |
3032 | } | |
3033 | ||
3034 | /* | |
3035 | * Must be called with the queue_lock held. | |
3036 | */ | |
3037 | static int cfqq_process_refs(struct cfq_queue *cfqq) | |
3038 | { | |
3039 | int process_refs, io_refs; | |
3040 | ||
3041 | io_refs = cfqq->allocated[READ] + cfqq->allocated[WRITE]; | |
3042 | process_refs = cfqq->ref - io_refs; | |
3043 | BUG_ON(process_refs < 0); | |
3044 | return process_refs; | |
3045 | } | |
3046 | ||
3047 | static void cfq_setup_merge(struct cfq_queue *cfqq, struct cfq_queue *new_cfqq) | |
3048 | { | |
3049 | int process_refs, new_process_refs; | |
3050 | struct cfq_queue *__cfqq; | |
3051 | ||
3052 | /* | |
3053 | * If there are no process references on the new_cfqq, then it is | |
3054 | * unsafe to follow the ->new_cfqq chain as other cfqq's in the | |
3055 | * chain may have dropped their last reference (not just their | |
3056 | * last process reference). | |
3057 | */ | |
3058 | if (!cfqq_process_refs(new_cfqq)) | |
3059 | return; | |
3060 | ||
3061 | /* Avoid a circular list and skip interim queue merges */ | |
3062 | while ((__cfqq = new_cfqq->new_cfqq)) { | |
3063 | if (__cfqq == cfqq) | |
3064 | return; | |
3065 | new_cfqq = __cfqq; | |
3066 | } | |
3067 | ||
3068 | process_refs = cfqq_process_refs(cfqq); | |
3069 | new_process_refs = cfqq_process_refs(new_cfqq); | |
3070 | /* | |
3071 | * If the process for the cfqq has gone away, there is no | |
3072 | * sense in merging the queues. | |
3073 | */ | |
3074 | if (process_refs == 0 || new_process_refs == 0) | |
3075 | return; | |
3076 | ||
3077 | /* | |
3078 | * Merge in the direction of the lesser amount of work. | |
3079 | */ | |
3080 | if (new_process_refs >= process_refs) { | |
3081 | cfqq->new_cfqq = new_cfqq; | |
3082 | new_cfqq->ref += process_refs; | |
3083 | } else { | |
3084 | new_cfqq->new_cfqq = cfqq; | |
3085 | cfqq->ref += new_process_refs; | |
3086 | } | |
3087 | } | |
3088 | ||
3089 | static enum wl_type_t cfq_choose_wl_type(struct cfq_data *cfqd, | |
3090 | struct cfq_group *cfqg, enum wl_class_t wl_class) | |
3091 | { | |
3092 | struct cfq_queue *queue; | |
3093 | int i; | |
3094 | bool key_valid = false; | |
3095 | u64 lowest_key = 0; | |
3096 | enum wl_type_t cur_best = SYNC_NOIDLE_WORKLOAD; | |
3097 | ||
3098 | for (i = 0; i <= SYNC_WORKLOAD; ++i) { | |
3099 | /* select the one with lowest rb_key */ | |
3100 | queue = cfq_rb_first(st_for(cfqg, wl_class, i)); | |
3101 | if (queue && | |
3102 | (!key_valid || queue->rb_key < lowest_key)) { | |
3103 | lowest_key = queue->rb_key; | |
3104 | cur_best = i; | |
3105 | key_valid = true; | |
3106 | } | |
3107 | } | |
3108 | ||
3109 | return cur_best; | |
3110 | } | |
3111 | ||
3112 | static void | |
3113 | choose_wl_class_and_type(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
3114 | { | |
3115 | u64 slice; | |
3116 | unsigned count; | |
3117 | struct cfq_rb_root *st; | |
3118 | u64 group_slice; | |
3119 | enum wl_class_t original_class = cfqd->serving_wl_class; | |
3120 | u64 now = ktime_get_ns(); | |
3121 | ||
3122 | /* Choose next priority. RT > BE > IDLE */ | |
3123 | if (cfq_group_busy_queues_wl(RT_WORKLOAD, cfqd, cfqg)) | |
3124 | cfqd->serving_wl_class = RT_WORKLOAD; | |
3125 | else if (cfq_group_busy_queues_wl(BE_WORKLOAD, cfqd, cfqg)) | |
3126 | cfqd->serving_wl_class = BE_WORKLOAD; | |
3127 | else { | |
3128 | cfqd->serving_wl_class = IDLE_WORKLOAD; | |
3129 | cfqd->workload_expires = now + jiffies_to_nsecs(1); | |
3130 | return; | |
3131 | } | |
3132 | ||
3133 | if (original_class != cfqd->serving_wl_class) | |
3134 | goto new_workload; | |
3135 | ||
3136 | /* | |
3137 | * For RT and BE, we have to choose also the type | |
3138 | * (SYNC, SYNC_NOIDLE, ASYNC), and to compute a workload | |
3139 | * expiration time | |
3140 | */ | |
3141 | st = st_for(cfqg, cfqd->serving_wl_class, cfqd->serving_wl_type); | |
3142 | count = st->count; | |
3143 | ||
3144 | /* | |
3145 | * check workload expiration, and that we still have other queues ready | |
3146 | */ | |
3147 | if (count && !(now > cfqd->workload_expires)) | |
3148 | return; | |
3149 | ||
3150 | new_workload: | |
3151 | /* otherwise select new workload type */ | |
3152 | cfqd->serving_wl_type = cfq_choose_wl_type(cfqd, cfqg, | |
3153 | cfqd->serving_wl_class); | |
3154 | st = st_for(cfqg, cfqd->serving_wl_class, cfqd->serving_wl_type); | |
3155 | count = st->count; | |
3156 | ||
3157 | /* | |
3158 | * the workload slice is computed as a fraction of target latency | |
3159 | * proportional to the number of queues in that workload, over | |
3160 | * all the queues in the same priority class | |
3161 | */ | |
3162 | group_slice = cfq_group_slice(cfqd, cfqg); | |
3163 | ||
3164 | slice = div_u64(group_slice * count, | |
3165 | max_t(unsigned, cfqg->busy_queues_avg[cfqd->serving_wl_class], | |
3166 | cfq_group_busy_queues_wl(cfqd->serving_wl_class, cfqd, | |
3167 | cfqg))); | |
3168 | ||
3169 | if (cfqd->serving_wl_type == ASYNC_WORKLOAD) { | |
3170 | u64 tmp; | |
3171 | ||
3172 | /* | |
3173 | * Async queues are currently system wide. Just taking | |
3174 | * proportion of queues with-in same group will lead to higher | |
3175 | * async ratio system wide as generally root group is going | |
3176 | * to have higher weight. A more accurate thing would be to | |
3177 | * calculate system wide asnc/sync ratio. | |
3178 | */ | |
3179 | tmp = cfqd->cfq_target_latency * | |
3180 | cfqg_busy_async_queues(cfqd, cfqg); | |
3181 | tmp = div_u64(tmp, cfqd->busy_queues); | |
3182 | slice = min_t(u64, slice, tmp); | |
3183 | ||
3184 | /* async workload slice is scaled down according to | |
3185 | * the sync/async slice ratio. */ | |
3186 | slice = div64_u64(slice*cfqd->cfq_slice[0], cfqd->cfq_slice[1]); | |
3187 | } else | |
3188 | /* sync workload slice is at least 2 * cfq_slice_idle */ | |
3189 | slice = max(slice, 2 * cfqd->cfq_slice_idle); | |
3190 | ||
3191 | slice = max_t(u64, slice, CFQ_MIN_TT); | |
3192 | cfq_log(cfqd, "workload slice:%llu", slice); | |
3193 | cfqd->workload_expires = now + slice; | |
3194 | } | |
3195 | ||
3196 | static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd) | |
3197 | { | |
3198 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
3199 | struct cfq_group *cfqg; | |
3200 | ||
3201 | if (RB_EMPTY_ROOT(&st->rb.rb_root)) | |
3202 | return NULL; | |
3203 | cfqg = cfq_rb_first_group(st); | |
3204 | update_min_vdisktime(st); | |
3205 | return cfqg; | |
3206 | } | |
3207 | ||
3208 | static void cfq_choose_cfqg(struct cfq_data *cfqd) | |
3209 | { | |
3210 | struct cfq_group *cfqg = cfq_get_next_cfqg(cfqd); | |
3211 | u64 now = ktime_get_ns(); | |
3212 | ||
3213 | cfqd->serving_group = cfqg; | |
3214 | ||
3215 | /* Restore the workload type data */ | |
3216 | if (cfqg->saved_wl_slice) { | |
3217 | cfqd->workload_expires = now + cfqg->saved_wl_slice; | |
3218 | cfqd->serving_wl_type = cfqg->saved_wl_type; | |
3219 | cfqd->serving_wl_class = cfqg->saved_wl_class; | |
3220 | } else | |
3221 | cfqd->workload_expires = now - 1; | |
3222 | ||
3223 | choose_wl_class_and_type(cfqd, cfqg); | |
3224 | } | |
3225 | ||
3226 | /* | |
3227 | * Select a queue for service. If we have a current active queue, | |
3228 | * check whether to continue servicing it, or retrieve and set a new one. | |
3229 | */ | |
3230 | static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) | |
3231 | { | |
3232 | struct cfq_queue *cfqq, *new_cfqq = NULL; | |
3233 | u64 now = ktime_get_ns(); | |
3234 | ||
3235 | cfqq = cfqd->active_queue; | |
3236 | if (!cfqq) | |
3237 | goto new_queue; | |
3238 | ||
3239 | if (!cfqd->rq_queued) | |
3240 | return NULL; | |
3241 | ||
3242 | /* | |
3243 | * We were waiting for group to get backlogged. Expire the queue | |
3244 | */ | |
3245 | if (cfq_cfqq_wait_busy(cfqq) && !RB_EMPTY_ROOT(&cfqq->sort_list)) | |
3246 | goto expire; | |
3247 | ||
3248 | /* | |
3249 | * The active queue has run out of time, expire it and select new. | |
3250 | */ | |
3251 | if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq)) { | |
3252 | /* | |
3253 | * If slice had not expired at the completion of last request | |
3254 | * we might not have turned on wait_busy flag. Don't expire | |
3255 | * the queue yet. Allow the group to get backlogged. | |
3256 | * | |
3257 | * The very fact that we have used the slice, that means we | |
3258 | * have been idling all along on this queue and it should be | |
3259 | * ok to wait for this request to complete. | |
3260 | */ | |
3261 | if (cfqq->cfqg->nr_cfqq == 1 && RB_EMPTY_ROOT(&cfqq->sort_list) | |
3262 | && cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) { | |
3263 | cfqq = NULL; | |
3264 | goto keep_queue; | |
3265 | } else | |
3266 | goto check_group_idle; | |
3267 | } | |
3268 | ||
3269 | /* | |
3270 | * The active queue has requests and isn't expired, allow it to | |
3271 | * dispatch. | |
3272 | */ | |
3273 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) | |
3274 | goto keep_queue; | |
3275 | ||
3276 | /* | |
3277 | * If another queue has a request waiting within our mean seek | |
3278 | * distance, let it run. The expire code will check for close | |
3279 | * cooperators and put the close queue at the front of the service | |
3280 | * tree. If possible, merge the expiring queue with the new cfqq. | |
3281 | */ | |
3282 | new_cfqq = cfq_close_cooperator(cfqd, cfqq); | |
3283 | if (new_cfqq) { | |
3284 | if (!cfqq->new_cfqq) | |
3285 | cfq_setup_merge(cfqq, new_cfqq); | |
3286 | goto expire; | |
3287 | } | |
3288 | ||
3289 | /* | |
3290 | * No requests pending. If the active queue still has requests in | |
3291 | * flight or is idling for a new request, allow either of these | |
3292 | * conditions to happen (or time out) before selecting a new queue. | |
3293 | */ | |
3294 | if (hrtimer_active(&cfqd->idle_slice_timer)) { | |
3295 | cfqq = NULL; | |
3296 | goto keep_queue; | |
3297 | } | |
3298 | ||
3299 | /* | |
3300 | * This is a deep seek queue, but the device is much faster than | |
3301 | * the queue can deliver, don't idle | |
3302 | **/ | |
3303 | if (CFQQ_SEEKY(cfqq) && cfq_cfqq_idle_window(cfqq) && | |
3304 | (cfq_cfqq_slice_new(cfqq) || | |
3305 | (cfqq->slice_end - now > now - cfqq->slice_start))) { | |
3306 | cfq_clear_cfqq_deep(cfqq); | |
3307 | cfq_clear_cfqq_idle_window(cfqq); | |
3308 | } | |
3309 | ||
3310 | if (cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) { | |
3311 | cfqq = NULL; | |
3312 | goto keep_queue; | |
3313 | } | |
3314 | ||
3315 | /* | |
3316 | * If group idle is enabled and there are requests dispatched from | |
3317 | * this group, wait for requests to complete. | |
3318 | */ | |
3319 | check_group_idle: | |
3320 | if (cfqd->cfq_group_idle && cfqq->cfqg->nr_cfqq == 1 && | |
3321 | cfqq->cfqg->dispatched && | |
3322 | !cfq_io_thinktime_big(cfqd, &cfqq->cfqg->ttime, true)) { | |
3323 | cfqq = NULL; | |
3324 | goto keep_queue; | |
3325 | } | |
3326 | ||
3327 | expire: | |
3328 | cfq_slice_expired(cfqd, 0); | |
3329 | new_queue: | |
3330 | /* | |
3331 | * Current queue expired. Check if we have to switch to a new | |
3332 | * service tree | |
3333 | */ | |
3334 | if (!new_cfqq) | |
3335 | cfq_choose_cfqg(cfqd); | |
3336 | ||
3337 | cfqq = cfq_set_active_queue(cfqd, new_cfqq); | |
3338 | keep_queue: | |
3339 | return cfqq; | |
3340 | } | |
3341 | ||
3342 | static int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq) | |
3343 | { | |
3344 | int dispatched = 0; | |
3345 | ||
3346 | while (cfqq->next_rq) { | |
3347 | cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq); | |
3348 | dispatched++; | |
3349 | } | |
3350 | ||
3351 | BUG_ON(!list_empty(&cfqq->fifo)); | |
3352 | ||
3353 | /* By default cfqq is not expired if it is empty. Do it explicitly */ | |
3354 | __cfq_slice_expired(cfqq->cfqd, cfqq, 0); | |
3355 | return dispatched; | |
3356 | } | |
3357 | ||
3358 | /* | |
3359 | * Drain our current requests. Used for barriers and when switching | |
3360 | * io schedulers on-the-fly. | |
3361 | */ | |
3362 | static int cfq_forced_dispatch(struct cfq_data *cfqd) | |
3363 | { | |
3364 | struct cfq_queue *cfqq; | |
3365 | int dispatched = 0; | |
3366 | ||
3367 | /* Expire the timeslice of the current active queue first */ | |
3368 | cfq_slice_expired(cfqd, 0); | |
3369 | while ((cfqq = cfq_get_next_queue_forced(cfqd)) != NULL) { | |
3370 | __cfq_set_active_queue(cfqd, cfqq); | |
3371 | dispatched += __cfq_forced_dispatch_cfqq(cfqq); | |
3372 | } | |
3373 | ||
3374 | BUG_ON(cfqd->busy_queues); | |
3375 | ||
3376 | cfq_log(cfqd, "forced_dispatch=%d", dispatched); | |
3377 | return dispatched; | |
3378 | } | |
3379 | ||
3380 | static inline bool cfq_slice_used_soon(struct cfq_data *cfqd, | |
3381 | struct cfq_queue *cfqq) | |
3382 | { | |
3383 | u64 now = ktime_get_ns(); | |
3384 | ||
3385 | /* the queue hasn't finished any request, can't estimate */ | |
3386 | if (cfq_cfqq_slice_new(cfqq)) | |
3387 | return true; | |
3388 | if (now + cfqd->cfq_slice_idle * cfqq->dispatched > cfqq->slice_end) | |
3389 | return true; | |
3390 | ||
3391 | return false; | |
3392 | } | |
3393 | ||
3394 | static bool cfq_may_dispatch(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
3395 | { | |
3396 | unsigned int max_dispatch; | |
3397 | ||
3398 | if (cfq_cfqq_must_dispatch(cfqq)) | |
3399 | return true; | |
3400 | ||
3401 | /* | |
3402 | * Drain async requests before we start sync IO | |
3403 | */ | |
3404 | if (cfq_should_idle(cfqd, cfqq) && cfqd->rq_in_flight[BLK_RW_ASYNC]) | |
3405 | return false; | |
3406 | ||
3407 | /* | |
3408 | * If this is an async queue and we have sync IO in flight, let it wait | |
3409 | */ | |
3410 | if (cfqd->rq_in_flight[BLK_RW_SYNC] && !cfq_cfqq_sync(cfqq)) | |
3411 | return false; | |
3412 | ||
3413 | max_dispatch = max_t(unsigned int, cfqd->cfq_quantum / 2, 1); | |
3414 | if (cfq_class_idle(cfqq)) | |
3415 | max_dispatch = 1; | |
3416 | ||
3417 | /* | |
3418 | * Does this cfqq already have too much IO in flight? | |
3419 | */ | |
3420 | if (cfqq->dispatched >= max_dispatch) { | |
3421 | bool promote_sync = false; | |
3422 | /* | |
3423 | * idle queue must always only have a single IO in flight | |
3424 | */ | |
3425 | if (cfq_class_idle(cfqq)) | |
3426 | return false; | |
3427 | ||
3428 | /* | |
3429 | * If there is only one sync queue | |
3430 | * we can ignore async queue here and give the sync | |
3431 | * queue no dispatch limit. The reason is a sync queue can | |
3432 | * preempt async queue, limiting the sync queue doesn't make | |
3433 | * sense. This is useful for aiostress test. | |
3434 | */ | |
3435 | if (cfq_cfqq_sync(cfqq) && cfqd->busy_sync_queues == 1) | |
3436 | promote_sync = true; | |
3437 | ||
3438 | /* | |
3439 | * We have other queues, don't allow more IO from this one | |
3440 | */ | |
3441 | if (cfqd->busy_queues > 1 && cfq_slice_used_soon(cfqd, cfqq) && | |
3442 | !promote_sync) | |
3443 | return false; | |
3444 | ||
3445 | /* | |
3446 | * Sole queue user, no limit | |
3447 | */ | |
3448 | if (cfqd->busy_queues == 1 || promote_sync) | |
3449 | max_dispatch = -1; | |
3450 | else | |
3451 | /* | |
3452 | * Normally we start throttling cfqq when cfq_quantum/2 | |
3453 | * requests have been dispatched. But we can drive | |
3454 | * deeper queue depths at the beginning of slice | |
3455 | * subjected to upper limit of cfq_quantum. | |
3456 | * */ | |
3457 | max_dispatch = cfqd->cfq_quantum; | |
3458 | } | |
3459 | ||
3460 | /* | |
3461 | * Async queues must wait a bit before being allowed dispatch. | |
3462 | * We also ramp up the dispatch depth gradually for async IO, | |
3463 | * based on the last sync IO we serviced | |
3464 | */ | |
3465 | if (!cfq_cfqq_sync(cfqq) && cfqd->cfq_latency) { | |
3466 | u64 last_sync = ktime_get_ns() - cfqd->last_delayed_sync; | |
3467 | unsigned int depth; | |
3468 | ||
3469 | depth = div64_u64(last_sync, cfqd->cfq_slice[1]); | |
3470 | if (!depth && !cfqq->dispatched) | |
3471 | depth = 1; | |
3472 | if (depth < max_dispatch) | |
3473 | max_dispatch = depth; | |
3474 | } | |
3475 | ||
3476 | /* | |
3477 | * If we're below the current max, allow a dispatch | |
3478 | */ | |
3479 | return cfqq->dispatched < max_dispatch; | |
3480 | } | |
3481 | ||
3482 | /* | |
3483 | * Dispatch a request from cfqq, moving them to the request queue | |
3484 | * dispatch list. | |
3485 | */ | |
3486 | static bool cfq_dispatch_request(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
3487 | { | |
3488 | struct request *rq; | |
3489 | ||
3490 | BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list)); | |
3491 | ||
3492 | rq = cfq_check_fifo(cfqq); | |
3493 | if (rq) | |
3494 | cfq_mark_cfqq_must_dispatch(cfqq); | |
3495 | ||
3496 | if (!cfq_may_dispatch(cfqd, cfqq)) | |
3497 | return false; | |
3498 | ||
3499 | /* | |
3500 | * follow expired path, else get first next available | |
3501 | */ | |
3502 | if (!rq) | |
3503 | rq = cfqq->next_rq; | |
3504 | else | |
3505 | cfq_log_cfqq(cfqq->cfqd, cfqq, "fifo=%p", rq); | |
3506 | ||
3507 | /* | |
3508 | * insert request into driver dispatch list | |
3509 | */ | |
3510 | cfq_dispatch_insert(cfqd->queue, rq); | |
3511 | ||
3512 | if (!cfqd->active_cic) { | |
3513 | struct cfq_io_cq *cic = RQ_CIC(rq); | |
3514 | ||
3515 | atomic_long_inc(&cic->icq.ioc->refcount); | |
3516 | cfqd->active_cic = cic; | |
3517 | } | |
3518 | ||
3519 | return true; | |
3520 | } | |
3521 | ||
3522 | /* | |
3523 | * Find the cfqq that we need to service and move a request from that to the | |
3524 | * dispatch list | |
3525 | */ | |
3526 | static int cfq_dispatch_requests(struct request_queue *q, int force) | |
3527 | { | |
3528 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
3529 | struct cfq_queue *cfqq; | |
3530 | ||
3531 | if (!cfqd->busy_queues) | |
3532 | return 0; | |
3533 | ||
3534 | if (unlikely(force)) | |
3535 | return cfq_forced_dispatch(cfqd); | |
3536 | ||
3537 | cfqq = cfq_select_queue(cfqd); | |
3538 | if (!cfqq) | |
3539 | return 0; | |
3540 | ||
3541 | /* | |
3542 | * Dispatch a request from this cfqq, if it is allowed | |
3543 | */ | |
3544 | if (!cfq_dispatch_request(cfqd, cfqq)) | |
3545 | return 0; | |
3546 | ||
3547 | cfqq->slice_dispatch++; | |
3548 | cfq_clear_cfqq_must_dispatch(cfqq); | |
3549 | ||
3550 | /* | |
3551 | * expire an async queue immediately if it has used up its slice. idle | |
3552 | * queue always expire after 1 dispatch round. | |
3553 | */ | |
3554 | if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) && | |
3555 | cfqq->slice_dispatch >= cfq_prio_to_maxrq(cfqd, cfqq)) || | |
3556 | cfq_class_idle(cfqq))) { | |
3557 | cfqq->slice_end = ktime_get_ns() + 1; | |
3558 | cfq_slice_expired(cfqd, 0); | |
3559 | } | |
3560 | ||
3561 | cfq_log_cfqq(cfqd, cfqq, "dispatched a request"); | |
3562 | return 1; | |
3563 | } | |
3564 | ||
3565 | /* | |
3566 | * task holds one reference to the queue, dropped when task exits. each rq | |
3567 | * in-flight on this queue also holds a reference, dropped when rq is freed. | |
3568 | * | |
3569 | * Each cfq queue took a reference on the parent group. Drop it now. | |
3570 | * queue lock must be held here. | |
3571 | */ | |
3572 | static void cfq_put_queue(struct cfq_queue *cfqq) | |
3573 | { | |
3574 | struct cfq_data *cfqd = cfqq->cfqd; | |
3575 | struct cfq_group *cfqg; | |
3576 | ||
3577 | BUG_ON(cfqq->ref <= 0); | |
3578 | ||
3579 | cfqq->ref--; | |
3580 | if (cfqq->ref) | |
3581 | return; | |
3582 | ||
3583 | cfq_log_cfqq(cfqd, cfqq, "put_queue"); | |
3584 | BUG_ON(rb_first(&cfqq->sort_list)); | |
3585 | BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]); | |
3586 | cfqg = cfqq->cfqg; | |
3587 | ||
3588 | if (unlikely(cfqd->active_queue == cfqq)) { | |
3589 | __cfq_slice_expired(cfqd, cfqq, 0); | |
3590 | cfq_schedule_dispatch(cfqd); | |
3591 | } | |
3592 | ||
3593 | BUG_ON(cfq_cfqq_on_rr(cfqq)); | |
3594 | kmem_cache_free(cfq_pool, cfqq); | |
3595 | cfqg_put(cfqg); | |
3596 | } | |
3597 | ||
3598 | static void cfq_put_cooperator(struct cfq_queue *cfqq) | |
3599 | { | |
3600 | struct cfq_queue *__cfqq, *next; | |
3601 | ||
3602 | /* | |
3603 | * If this queue was scheduled to merge with another queue, be | |
3604 | * sure to drop the reference taken on that queue (and others in | |
3605 | * the merge chain). See cfq_setup_merge and cfq_merge_cfqqs. | |
3606 | */ | |
3607 | __cfqq = cfqq->new_cfqq; | |
3608 | while (__cfqq) { | |
3609 | if (__cfqq == cfqq) { | |
3610 | WARN(1, "cfqq->new_cfqq loop detected\n"); | |
3611 | break; | |
3612 | } | |
3613 | next = __cfqq->new_cfqq; | |
3614 | cfq_put_queue(__cfqq); | |
3615 | __cfqq = next; | |
3616 | } | |
3617 | } | |
3618 | ||
3619 | static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
3620 | { | |
3621 | if (unlikely(cfqq == cfqd->active_queue)) { | |
3622 | __cfq_slice_expired(cfqd, cfqq, 0); | |
3623 | cfq_schedule_dispatch(cfqd); | |
3624 | } | |
3625 | ||
3626 | cfq_put_cooperator(cfqq); | |
3627 | ||
3628 | cfq_put_queue(cfqq); | |
3629 | } | |
3630 | ||
3631 | static void cfq_init_icq(struct io_cq *icq) | |
3632 | { | |
3633 | struct cfq_io_cq *cic = icq_to_cic(icq); | |
3634 | ||
3635 | cic->ttime.last_end_request = ktime_get_ns(); | |
3636 | } | |
3637 | ||
3638 | static void cfq_exit_icq(struct io_cq *icq) | |
3639 | { | |
3640 | struct cfq_io_cq *cic = icq_to_cic(icq); | |
3641 | struct cfq_data *cfqd = cic_to_cfqd(cic); | |
3642 | ||
3643 | if (cic_to_cfqq(cic, false)) { | |
3644 | cfq_exit_cfqq(cfqd, cic_to_cfqq(cic, false)); | |
3645 | cic_set_cfqq(cic, NULL, false); | |
3646 | } | |
3647 | ||
3648 | if (cic_to_cfqq(cic, true)) { | |
3649 | cfq_exit_cfqq(cfqd, cic_to_cfqq(cic, true)); | |
3650 | cic_set_cfqq(cic, NULL, true); | |
3651 | } | |
3652 | } | |
3653 | ||
3654 | static void cfq_init_prio_data(struct cfq_queue *cfqq, struct cfq_io_cq *cic) | |
3655 | { | |
3656 | struct task_struct *tsk = current; | |
3657 | int ioprio_class; | |
3658 | ||
3659 | if (!cfq_cfqq_prio_changed(cfqq)) | |
3660 | return; | |
3661 | ||
3662 | ioprio_class = IOPRIO_PRIO_CLASS(cic->ioprio); | |
3663 | switch (ioprio_class) { | |
3664 | default: | |
3665 | printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class); | |
3666 | case IOPRIO_CLASS_NONE: | |
3667 | /* | |
3668 | * no prio set, inherit CPU scheduling settings | |
3669 | */ | |
3670 | cfqq->ioprio = task_nice_ioprio(tsk); | |
3671 | cfqq->ioprio_class = task_nice_ioclass(tsk); | |
3672 | break; | |
3673 | case IOPRIO_CLASS_RT: | |
3674 | cfqq->ioprio = IOPRIO_PRIO_DATA(cic->ioprio); | |
3675 | cfqq->ioprio_class = IOPRIO_CLASS_RT; | |
3676 | break; | |
3677 | case IOPRIO_CLASS_BE: | |
3678 | cfqq->ioprio = IOPRIO_PRIO_DATA(cic->ioprio); | |
3679 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
3680 | break; | |
3681 | case IOPRIO_CLASS_IDLE: | |
3682 | cfqq->ioprio_class = IOPRIO_CLASS_IDLE; | |
3683 | cfqq->ioprio = 7; | |
3684 | cfq_clear_cfqq_idle_window(cfqq); | |
3685 | break; | |
3686 | } | |
3687 | ||
3688 | /* | |
3689 | * keep track of original prio settings in case we have to temporarily | |
3690 | * elevate the priority of this queue | |
3691 | */ | |
3692 | cfqq->org_ioprio = cfqq->ioprio; | |
3693 | cfqq->org_ioprio_class = cfqq->ioprio_class; | |
3694 | cfq_clear_cfqq_prio_changed(cfqq); | |
3695 | } | |
3696 | ||
3697 | static void check_ioprio_changed(struct cfq_io_cq *cic, struct bio *bio) | |
3698 | { | |
3699 | int ioprio = cic->icq.ioc->ioprio; | |
3700 | struct cfq_data *cfqd = cic_to_cfqd(cic); | |
3701 | struct cfq_queue *cfqq; | |
3702 | ||
3703 | /* | |
3704 | * Check whether ioprio has changed. The condition may trigger | |
3705 | * spuriously on a newly created cic but there's no harm. | |
3706 | */ | |
3707 | if (unlikely(!cfqd) || likely(cic->ioprio == ioprio)) | |
3708 | return; | |
3709 | ||
3710 | cfqq = cic_to_cfqq(cic, false); | |
3711 | if (cfqq) { | |
3712 | cfq_put_queue(cfqq); | |
3713 | cfqq = cfq_get_queue(cfqd, BLK_RW_ASYNC, cic, bio); | |
3714 | cic_set_cfqq(cic, cfqq, false); | |
3715 | } | |
3716 | ||
3717 | cfqq = cic_to_cfqq(cic, true); | |
3718 | if (cfqq) | |
3719 | cfq_mark_cfqq_prio_changed(cfqq); | |
3720 | ||
3721 | cic->ioprio = ioprio; | |
3722 | } | |
3723 | ||
3724 | static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
3725 | pid_t pid, bool is_sync) | |
3726 | { | |
3727 | RB_CLEAR_NODE(&cfqq->rb_node); | |
3728 | RB_CLEAR_NODE(&cfqq->p_node); | |
3729 | INIT_LIST_HEAD(&cfqq->fifo); | |
3730 | ||
3731 | cfqq->ref = 0; | |
3732 | cfqq->cfqd = cfqd; | |
3733 | ||
3734 | cfq_mark_cfqq_prio_changed(cfqq); | |
3735 | ||
3736 | if (is_sync) { | |
3737 | if (!cfq_class_idle(cfqq)) | |
3738 | cfq_mark_cfqq_idle_window(cfqq); | |
3739 | cfq_mark_cfqq_sync(cfqq); | |
3740 | } | |
3741 | cfqq->pid = pid; | |
3742 | } | |
3743 | ||
3744 | #ifdef CONFIG_CFQ_GROUP_IOSCHED | |
3745 | static void check_blkcg_changed(struct cfq_io_cq *cic, struct bio *bio) | |
3746 | { | |
3747 | struct cfq_data *cfqd = cic_to_cfqd(cic); | |
3748 | struct cfq_queue *cfqq; | |
3749 | uint64_t serial_nr; | |
3750 | ||
3751 | rcu_read_lock(); | |
3752 | serial_nr = bio_blkcg(bio)->css.serial_nr; | |
3753 | rcu_read_unlock(); | |
3754 | ||
3755 | /* | |
3756 | * Check whether blkcg has changed. The condition may trigger | |
3757 | * spuriously on a newly created cic but there's no harm. | |
3758 | */ | |
3759 | if (unlikely(!cfqd) || likely(cic->blkcg_serial_nr == serial_nr)) | |
3760 | return; | |
3761 | ||
3762 | /* | |
3763 | * Drop reference to queues. New queues will be assigned in new | |
3764 | * group upon arrival of fresh requests. | |
3765 | */ | |
3766 | cfqq = cic_to_cfqq(cic, false); | |
3767 | if (cfqq) { | |
3768 | cfq_log_cfqq(cfqd, cfqq, "changed cgroup"); | |
3769 | cic_set_cfqq(cic, NULL, false); | |
3770 | cfq_put_queue(cfqq); | |
3771 | } | |
3772 | ||
3773 | cfqq = cic_to_cfqq(cic, true); | |
3774 | if (cfqq) { | |
3775 | cfq_log_cfqq(cfqd, cfqq, "changed cgroup"); | |
3776 | cic_set_cfqq(cic, NULL, true); | |
3777 | cfq_put_queue(cfqq); | |
3778 | } | |
3779 | ||
3780 | cic->blkcg_serial_nr = serial_nr; | |
3781 | } | |
3782 | #else | |
3783 | static inline void check_blkcg_changed(struct cfq_io_cq *cic, struct bio *bio) | |
3784 | { | |
3785 | } | |
3786 | #endif /* CONFIG_CFQ_GROUP_IOSCHED */ | |
3787 | ||
3788 | static struct cfq_queue ** | |
3789 | cfq_async_queue_prio(struct cfq_group *cfqg, int ioprio_class, int ioprio) | |
3790 | { | |
3791 | switch (ioprio_class) { | |
3792 | case IOPRIO_CLASS_RT: | |
3793 | return &cfqg->async_cfqq[0][ioprio]; | |
3794 | case IOPRIO_CLASS_NONE: | |
3795 | ioprio = IOPRIO_NORM; | |
3796 | /* fall through */ | |
3797 | case IOPRIO_CLASS_BE: | |
3798 | return &cfqg->async_cfqq[1][ioprio]; | |
3799 | case IOPRIO_CLASS_IDLE: | |
3800 | return &cfqg->async_idle_cfqq; | |
3801 | default: | |
3802 | BUG(); | |
3803 | } | |
3804 | } | |
3805 | ||
3806 | static struct cfq_queue * | |
3807 | cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct cfq_io_cq *cic, | |
3808 | struct bio *bio) | |
3809 | { | |
3810 | int ioprio_class = IOPRIO_PRIO_CLASS(cic->ioprio); | |
3811 | int ioprio = IOPRIO_PRIO_DATA(cic->ioprio); | |
3812 | struct cfq_queue **async_cfqq = NULL; | |
3813 | struct cfq_queue *cfqq; | |
3814 | struct cfq_group *cfqg; | |
3815 | ||
3816 | rcu_read_lock(); | |
3817 | cfqg = cfq_lookup_cfqg(cfqd, bio_blkcg(bio)); | |
3818 | if (!cfqg) { | |
3819 | cfqq = &cfqd->oom_cfqq; | |
3820 | goto out; | |
3821 | } | |
3822 | ||
3823 | if (!is_sync) { | |
3824 | if (!ioprio_valid(cic->ioprio)) { | |
3825 | struct task_struct *tsk = current; | |
3826 | ioprio = task_nice_ioprio(tsk); | |
3827 | ioprio_class = task_nice_ioclass(tsk); | |
3828 | } | |
3829 | async_cfqq = cfq_async_queue_prio(cfqg, ioprio_class, ioprio); | |
3830 | cfqq = *async_cfqq; | |
3831 | if (cfqq) | |
3832 | goto out; | |
3833 | } | |
3834 | ||
3835 | cfqq = kmem_cache_alloc_node(cfq_pool, | |
3836 | GFP_NOWAIT | __GFP_ZERO | __GFP_NOWARN, | |
3837 | cfqd->queue->node); | |
3838 | if (!cfqq) { | |
3839 | cfqq = &cfqd->oom_cfqq; | |
3840 | goto out; | |
3841 | } | |
3842 | ||
3843 | /* cfq_init_cfqq() assumes cfqq->ioprio_class is initialized. */ | |
3844 | cfqq->ioprio_class = IOPRIO_CLASS_NONE; | |
3845 | cfq_init_cfqq(cfqd, cfqq, current->pid, is_sync); | |
3846 | cfq_init_prio_data(cfqq, cic); | |
3847 | cfq_link_cfqq_cfqg(cfqq, cfqg); | |
3848 | cfq_log_cfqq(cfqd, cfqq, "alloced"); | |
3849 | ||
3850 | if (async_cfqq) { | |
3851 | /* a new async queue is created, pin and remember */ | |
3852 | cfqq->ref++; | |
3853 | *async_cfqq = cfqq; | |
3854 | } | |
3855 | out: | |
3856 | cfqq->ref++; | |
3857 | rcu_read_unlock(); | |
3858 | return cfqq; | |
3859 | } | |
3860 | ||
3861 | static void | |
3862 | __cfq_update_io_thinktime(struct cfq_ttime *ttime, u64 slice_idle) | |
3863 | { | |
3864 | u64 elapsed = ktime_get_ns() - ttime->last_end_request; | |
3865 | elapsed = min(elapsed, 2UL * slice_idle); | |
3866 | ||
3867 | ttime->ttime_samples = (7*ttime->ttime_samples + 256) / 8; | |
3868 | ttime->ttime_total = div_u64(7*ttime->ttime_total + 256*elapsed, 8); | |
3869 | ttime->ttime_mean = div64_ul(ttime->ttime_total + 128, | |
3870 | ttime->ttime_samples); | |
3871 | } | |
3872 | ||
3873 | static void | |
3874 | cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
3875 | struct cfq_io_cq *cic) | |
3876 | { | |
3877 | if (cfq_cfqq_sync(cfqq)) { | |
3878 | __cfq_update_io_thinktime(&cic->ttime, cfqd->cfq_slice_idle); | |
3879 | __cfq_update_io_thinktime(&cfqq->service_tree->ttime, | |
3880 | cfqd->cfq_slice_idle); | |
3881 | } | |
3882 | #ifdef CONFIG_CFQ_GROUP_IOSCHED | |
3883 | __cfq_update_io_thinktime(&cfqq->cfqg->ttime, cfqd->cfq_group_idle); | |
3884 | #endif | |
3885 | } | |
3886 | ||
3887 | static void | |
3888 | cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
3889 | struct request *rq) | |
3890 | { | |
3891 | sector_t sdist = 0; | |
3892 | sector_t n_sec = blk_rq_sectors(rq); | |
3893 | if (cfqq->last_request_pos) { | |
3894 | if (cfqq->last_request_pos < blk_rq_pos(rq)) | |
3895 | sdist = blk_rq_pos(rq) - cfqq->last_request_pos; | |
3896 | else | |
3897 | sdist = cfqq->last_request_pos - blk_rq_pos(rq); | |
3898 | } | |
3899 | ||
3900 | cfqq->seek_history <<= 1; | |
3901 | if (blk_queue_nonrot(cfqd->queue)) | |
3902 | cfqq->seek_history |= (n_sec < CFQQ_SECT_THR_NONROT); | |
3903 | else | |
3904 | cfqq->seek_history |= (sdist > CFQQ_SEEK_THR); | |
3905 | } | |
3906 | ||
3907 | static inline bool req_noidle(struct request *req) | |
3908 | { | |
3909 | return req_op(req) == REQ_OP_WRITE && | |
3910 | (req->cmd_flags & (REQ_SYNC | REQ_IDLE)) == REQ_SYNC; | |
3911 | } | |
3912 | ||
3913 | /* | |
3914 | * Disable idle window if the process thinks too long or seeks so much that | |
3915 | * it doesn't matter | |
3916 | */ | |
3917 | static void | |
3918 | cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
3919 | struct cfq_io_cq *cic) | |
3920 | { | |
3921 | int old_idle, enable_idle; | |
3922 | ||
3923 | /* | |
3924 | * Don't idle for async or idle io prio class | |
3925 | */ | |
3926 | if (!cfq_cfqq_sync(cfqq) || cfq_class_idle(cfqq)) | |
3927 | return; | |
3928 | ||
3929 | enable_idle = old_idle = cfq_cfqq_idle_window(cfqq); | |
3930 | ||
3931 | if (cfqq->queued[0] + cfqq->queued[1] >= 4) | |
3932 | cfq_mark_cfqq_deep(cfqq); | |
3933 | ||
3934 | if (cfqq->next_rq && req_noidle(cfqq->next_rq)) | |
3935 | enable_idle = 0; | |
3936 | else if (!atomic_read(&cic->icq.ioc->active_ref) || | |
3937 | !cfqd->cfq_slice_idle || | |
3938 | (!cfq_cfqq_deep(cfqq) && CFQQ_SEEKY(cfqq))) | |
3939 | enable_idle = 0; | |
3940 | else if (sample_valid(cic->ttime.ttime_samples)) { | |
3941 | if (cic->ttime.ttime_mean > cfqd->cfq_slice_idle) | |
3942 | enable_idle = 0; | |
3943 | else | |
3944 | enable_idle = 1; | |
3945 | } | |
3946 | ||
3947 | if (old_idle != enable_idle) { | |
3948 | cfq_log_cfqq(cfqd, cfqq, "idle=%d", enable_idle); | |
3949 | if (enable_idle) | |
3950 | cfq_mark_cfqq_idle_window(cfqq); | |
3951 | else | |
3952 | cfq_clear_cfqq_idle_window(cfqq); | |
3953 | } | |
3954 | } | |
3955 | ||
3956 | /* | |
3957 | * Check if new_cfqq should preempt the currently active queue. Return 0 for | |
3958 | * no or if we aren't sure, a 1 will cause a preempt. | |
3959 | */ | |
3960 | static bool | |
3961 | cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, | |
3962 | struct request *rq) | |
3963 | { | |
3964 | struct cfq_queue *cfqq; | |
3965 | ||
3966 | cfqq = cfqd->active_queue; | |
3967 | if (!cfqq) | |
3968 | return false; | |
3969 | ||
3970 | if (cfq_class_idle(new_cfqq)) | |
3971 | return false; | |
3972 | ||
3973 | if (cfq_class_idle(cfqq)) | |
3974 | return true; | |
3975 | ||
3976 | /* | |
3977 | * Don't allow a non-RT request to preempt an ongoing RT cfqq timeslice. | |
3978 | */ | |
3979 | if (cfq_class_rt(cfqq) && !cfq_class_rt(new_cfqq)) | |
3980 | return false; | |
3981 | ||
3982 | /* | |
3983 | * if the new request is sync, but the currently running queue is | |
3984 | * not, let the sync request have priority. | |
3985 | */ | |
3986 | if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq) && !cfq_cfqq_must_dispatch(cfqq)) | |
3987 | return true; | |
3988 | ||
3989 | /* | |
3990 | * Treat ancestors of current cgroup the same way as current cgroup. | |
3991 | * For anybody else we disallow preemption to guarantee service | |
3992 | * fairness among cgroups. | |
3993 | */ | |
3994 | if (!cfqg_is_descendant(cfqq->cfqg, new_cfqq->cfqg)) | |
3995 | return false; | |
3996 | ||
3997 | if (cfq_slice_used(cfqq)) | |
3998 | return true; | |
3999 | ||
4000 | /* | |
4001 | * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice. | |
4002 | */ | |
4003 | if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq)) | |
4004 | return true; | |
4005 | ||
4006 | WARN_ON_ONCE(cfqq->ioprio_class != new_cfqq->ioprio_class); | |
4007 | /* Allow preemption only if we are idling on sync-noidle tree */ | |
4008 | if (cfqd->serving_wl_type == SYNC_NOIDLE_WORKLOAD && | |
4009 | cfqq_type(new_cfqq) == SYNC_NOIDLE_WORKLOAD && | |
4010 | RB_EMPTY_ROOT(&cfqq->sort_list)) | |
4011 | return true; | |
4012 | ||
4013 | /* | |
4014 | * So both queues are sync. Let the new request get disk time if | |
4015 | * it's a metadata request and the current queue is doing regular IO. | |
4016 | */ | |
4017 | if ((rq->cmd_flags & REQ_PRIO) && !cfqq->prio_pending) | |
4018 | return true; | |
4019 | ||
4020 | /* An idle queue should not be idle now for some reason */ | |
4021 | if (RB_EMPTY_ROOT(&cfqq->sort_list) && !cfq_should_idle(cfqd, cfqq)) | |
4022 | return true; | |
4023 | ||
4024 | if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq)) | |
4025 | return false; | |
4026 | ||
4027 | /* | |
4028 | * if this request is as-good as one we would expect from the | |
4029 | * current cfqq, let it preempt | |
4030 | */ | |
4031 | if (cfq_rq_close(cfqd, cfqq, rq)) | |
4032 | return true; | |
4033 | ||
4034 | return false; | |
4035 | } | |
4036 | ||
4037 | /* | |
4038 | * cfqq preempts the active queue. if we allowed preempt with no slice left, | |
4039 | * let it have half of its nominal slice. | |
4040 | */ | |
4041 | static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
4042 | { | |
4043 | enum wl_type_t old_type = cfqq_type(cfqd->active_queue); | |
4044 | ||
4045 | cfq_log_cfqq(cfqd, cfqq, "preempt"); | |
4046 | cfq_slice_expired(cfqd, 1); | |
4047 | ||
4048 | /* | |
4049 | * workload type is changed, don't save slice, otherwise preempt | |
4050 | * doesn't happen | |
4051 | */ | |
4052 | if (old_type != cfqq_type(cfqq)) | |
4053 | cfqq->cfqg->saved_wl_slice = 0; | |
4054 | ||
4055 | /* | |
4056 | * Put the new queue at the front of the of the current list, | |
4057 | * so we know that it will be selected next. | |
4058 | */ | |
4059 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); | |
4060 | ||
4061 | cfq_service_tree_add(cfqd, cfqq, 1); | |
4062 | ||
4063 | cfqq->slice_end = 0; | |
4064 | cfq_mark_cfqq_slice_new(cfqq); | |
4065 | } | |
4066 | ||
4067 | /* | |
4068 | * Called when a new fs request (rq) is added (to cfqq). Check if there's | |
4069 | * something we should do about it | |
4070 | */ | |
4071 | static void | |
4072 | cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
4073 | struct request *rq) | |
4074 | { | |
4075 | struct cfq_io_cq *cic = RQ_CIC(rq); | |
4076 | ||
4077 | cfqd->rq_queued++; | |
4078 | if (rq->cmd_flags & REQ_PRIO) | |
4079 | cfqq->prio_pending++; | |
4080 | ||
4081 | cfq_update_io_thinktime(cfqd, cfqq, cic); | |
4082 | cfq_update_io_seektime(cfqd, cfqq, rq); | |
4083 | cfq_update_idle_window(cfqd, cfqq, cic); | |
4084 | ||
4085 | cfqq->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq); | |
4086 | ||
4087 | if (cfqq == cfqd->active_queue) { | |
4088 | /* | |
4089 | * Remember that we saw a request from this process, but | |
4090 | * don't start queuing just yet. Otherwise we risk seeing lots | |
4091 | * of tiny requests, because we disrupt the normal plugging | |
4092 | * and merging. If the request is already larger than a single | |
4093 | * page, let it rip immediately. For that case we assume that | |
4094 | * merging is already done. Ditto for a busy system that | |
4095 | * has other work pending, don't risk delaying until the | |
4096 | * idle timer unplug to continue working. | |
4097 | */ | |
4098 | if (cfq_cfqq_wait_request(cfqq)) { | |
4099 | if (blk_rq_bytes(rq) > PAGE_SIZE || | |
4100 | cfqd->busy_queues > 1) { | |
4101 | cfq_del_timer(cfqd, cfqq); | |
4102 | cfq_clear_cfqq_wait_request(cfqq); | |
4103 | __blk_run_queue(cfqd->queue); | |
4104 | } else { | |
4105 | cfqg_stats_update_idle_time(cfqq->cfqg); | |
4106 | cfq_mark_cfqq_must_dispatch(cfqq); | |
4107 | } | |
4108 | } | |
4109 | } else if (cfq_should_preempt(cfqd, cfqq, rq)) { | |
4110 | /* | |
4111 | * not the active queue - expire current slice if it is | |
4112 | * idle and has expired it's mean thinktime or this new queue | |
4113 | * has some old slice time left and is of higher priority or | |
4114 | * this new queue is RT and the current one is BE | |
4115 | */ | |
4116 | cfq_preempt_queue(cfqd, cfqq); | |
4117 | __blk_run_queue(cfqd->queue); | |
4118 | } | |
4119 | } | |
4120 | ||
4121 | static void cfq_insert_request(struct request_queue *q, struct request *rq) | |
4122 | { | |
4123 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
4124 | struct cfq_queue *cfqq = RQ_CFQQ(rq); | |
4125 | ||
4126 | cfq_log_cfqq(cfqd, cfqq, "insert_request"); | |
4127 | cfq_init_prio_data(cfqq, RQ_CIC(rq)); | |
4128 | ||
4129 | rq->fifo_time = ktime_get_ns() + cfqd->cfq_fifo_expire[rq_is_sync(rq)]; | |
4130 | list_add_tail(&rq->queuelist, &cfqq->fifo); | |
4131 | cfq_add_rq_rb(rq); | |
4132 | cfqg_stats_update_io_add(RQ_CFQG(rq), cfqd->serving_group, | |
4133 | rq->cmd_flags); | |
4134 | cfq_rq_enqueued(cfqd, cfqq, rq); | |
4135 | } | |
4136 | ||
4137 | /* | |
4138 | * Update hw_tag based on peak queue depth over 50 samples under | |
4139 | * sufficient load. | |
4140 | */ | |
4141 | static void cfq_update_hw_tag(struct cfq_data *cfqd) | |
4142 | { | |
4143 | struct cfq_queue *cfqq = cfqd->active_queue; | |
4144 | ||
4145 | if (cfqd->rq_in_driver > cfqd->hw_tag_est_depth) | |
4146 | cfqd->hw_tag_est_depth = cfqd->rq_in_driver; | |
4147 | ||
4148 | if (cfqd->hw_tag == 1) | |
4149 | return; | |
4150 | ||
4151 | if (cfqd->rq_queued <= CFQ_HW_QUEUE_MIN && | |
4152 | cfqd->rq_in_driver <= CFQ_HW_QUEUE_MIN) | |
4153 | return; | |
4154 | ||
4155 | /* | |
4156 | * If active queue hasn't enough requests and can idle, cfq might not | |
4157 | * dispatch sufficient requests to hardware. Don't zero hw_tag in this | |
4158 | * case | |
4159 | */ | |
4160 | if (cfqq && cfq_cfqq_idle_window(cfqq) && | |
4161 | cfqq->dispatched + cfqq->queued[0] + cfqq->queued[1] < | |
4162 | CFQ_HW_QUEUE_MIN && cfqd->rq_in_driver < CFQ_HW_QUEUE_MIN) | |
4163 | return; | |
4164 | ||
4165 | if (cfqd->hw_tag_samples++ < 50) | |
4166 | return; | |
4167 | ||
4168 | if (cfqd->hw_tag_est_depth >= CFQ_HW_QUEUE_MIN) | |
4169 | cfqd->hw_tag = 1; | |
4170 | else | |
4171 | cfqd->hw_tag = 0; | |
4172 | } | |
4173 | ||
4174 | static bool cfq_should_wait_busy(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
4175 | { | |
4176 | struct cfq_io_cq *cic = cfqd->active_cic; | |
4177 | u64 now = ktime_get_ns(); | |
4178 | ||
4179 | /* If the queue already has requests, don't wait */ | |
4180 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) | |
4181 | return false; | |
4182 | ||
4183 | /* If there are other queues in the group, don't wait */ | |
4184 | if (cfqq->cfqg->nr_cfqq > 1) | |
4185 | return false; | |
4186 | ||
4187 | /* the only queue in the group, but think time is big */ | |
4188 | if (cfq_io_thinktime_big(cfqd, &cfqq->cfqg->ttime, true)) | |
4189 | return false; | |
4190 | ||
4191 | if (cfq_slice_used(cfqq)) | |
4192 | return true; | |
4193 | ||
4194 | /* if slice left is less than think time, wait busy */ | |
4195 | if (cic && sample_valid(cic->ttime.ttime_samples) | |
4196 | && (cfqq->slice_end - now < cic->ttime.ttime_mean)) | |
4197 | return true; | |
4198 | ||
4199 | /* | |
4200 | * If think times is less than a jiffy than ttime_mean=0 and above | |
4201 | * will not be true. It might happen that slice has not expired yet | |
4202 | * but will expire soon (4-5 ns) during select_queue(). To cover the | |
4203 | * case where think time is less than a jiffy, mark the queue wait | |
4204 | * busy if only 1 jiffy is left in the slice. | |
4205 | */ | |
4206 | if (cfqq->slice_end - now <= jiffies_to_nsecs(1)) | |
4207 | return true; | |
4208 | ||
4209 | return false; | |
4210 | } | |
4211 | ||
4212 | static void cfq_completed_request(struct request_queue *q, struct request *rq) | |
4213 | { | |
4214 | struct cfq_queue *cfqq = RQ_CFQQ(rq); | |
4215 | struct cfq_data *cfqd = cfqq->cfqd; | |
4216 | const int sync = rq_is_sync(rq); | |
4217 | u64 now = ktime_get_ns(); | |
4218 | ||
4219 | cfq_log_cfqq(cfqd, cfqq, "complete rqnoidle %d", req_noidle(rq)); | |
4220 | ||
4221 | cfq_update_hw_tag(cfqd); | |
4222 | ||
4223 | WARN_ON(!cfqd->rq_in_driver); | |
4224 | WARN_ON(!cfqq->dispatched); | |
4225 | cfqd->rq_in_driver--; | |
4226 | cfqq->dispatched--; | |
4227 | (RQ_CFQG(rq))->dispatched--; | |
4228 | cfqg_stats_update_completion(cfqq->cfqg, rq_start_time_ns(rq), | |
4229 | rq_io_start_time_ns(rq), rq->cmd_flags); | |
4230 | ||
4231 | cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]--; | |
4232 | ||
4233 | if (sync) { | |
4234 | struct cfq_rb_root *st; | |
4235 | ||
4236 | RQ_CIC(rq)->ttime.last_end_request = now; | |
4237 | ||
4238 | if (cfq_cfqq_on_rr(cfqq)) | |
4239 | st = cfqq->service_tree; | |
4240 | else | |
4241 | st = st_for(cfqq->cfqg, cfqq_class(cfqq), | |
4242 | cfqq_type(cfqq)); | |
4243 | ||
4244 | st->ttime.last_end_request = now; | |
4245 | /* | |
4246 | * We have to do this check in jiffies since start_time is in | |
4247 | * jiffies and it is not trivial to convert to ns. If | |
4248 | * cfq_fifo_expire[1] ever comes close to 1 jiffie, this test | |
4249 | * will become problematic but so far we are fine (the default | |
4250 | * is 128 ms). | |
4251 | */ | |
4252 | if (!time_after(rq->start_time + | |
4253 | nsecs_to_jiffies(cfqd->cfq_fifo_expire[1]), | |
4254 | jiffies)) | |
4255 | cfqd->last_delayed_sync = now; | |
4256 | } | |
4257 | ||
4258 | #ifdef CONFIG_CFQ_GROUP_IOSCHED | |
4259 | cfqq->cfqg->ttime.last_end_request = now; | |
4260 | #endif | |
4261 | ||
4262 | /* | |
4263 | * If this is the active queue, check if it needs to be expired, | |
4264 | * or if we want to idle in case it has no pending requests. | |
4265 | */ | |
4266 | if (cfqd->active_queue == cfqq) { | |
4267 | const bool cfqq_empty = RB_EMPTY_ROOT(&cfqq->sort_list); | |
4268 | ||
4269 | if (cfq_cfqq_slice_new(cfqq)) { | |
4270 | cfq_set_prio_slice(cfqd, cfqq); | |
4271 | cfq_clear_cfqq_slice_new(cfqq); | |
4272 | } | |
4273 | ||
4274 | /* | |
4275 | * Should we wait for next request to come in before we expire | |
4276 | * the queue. | |
4277 | */ | |
4278 | if (cfq_should_wait_busy(cfqd, cfqq)) { | |
4279 | u64 extend_sl = cfqd->cfq_slice_idle; | |
4280 | if (!cfqd->cfq_slice_idle) | |
4281 | extend_sl = cfqd->cfq_group_idle; | |
4282 | cfqq->slice_end = now + extend_sl; | |
4283 | cfq_mark_cfqq_wait_busy(cfqq); | |
4284 | cfq_log_cfqq(cfqd, cfqq, "will busy wait"); | |
4285 | } | |
4286 | ||
4287 | /* | |
4288 | * Idling is not enabled on: | |
4289 | * - expired queues | |
4290 | * - idle-priority queues | |
4291 | * - async queues | |
4292 | * - queues with still some requests queued | |
4293 | * - when there is a close cooperator | |
4294 | */ | |
4295 | if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq)) | |
4296 | cfq_slice_expired(cfqd, 1); | |
4297 | else if (sync && cfqq_empty && | |
4298 | !cfq_close_cooperator(cfqd, cfqq)) { | |
4299 | cfq_arm_slice_timer(cfqd); | |
4300 | } | |
4301 | } | |
4302 | ||
4303 | if (!cfqd->rq_in_driver) | |
4304 | cfq_schedule_dispatch(cfqd); | |
4305 | } | |
4306 | ||
4307 | static void cfqq_boost_on_prio(struct cfq_queue *cfqq, unsigned int op) | |
4308 | { | |
4309 | /* | |
4310 | * If REQ_PRIO is set, boost class and prio level, if it's below | |
4311 | * BE/NORM. If prio is not set, restore the potentially boosted | |
4312 | * class/prio level. | |
4313 | */ | |
4314 | if (!(op & REQ_PRIO)) { | |
4315 | cfqq->ioprio_class = cfqq->org_ioprio_class; | |
4316 | cfqq->ioprio = cfqq->org_ioprio; | |
4317 | } else { | |
4318 | if (cfq_class_idle(cfqq)) | |
4319 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
4320 | if (cfqq->ioprio > IOPRIO_NORM) | |
4321 | cfqq->ioprio = IOPRIO_NORM; | |
4322 | } | |
4323 | } | |
4324 | ||
4325 | static inline int __cfq_may_queue(struct cfq_queue *cfqq) | |
4326 | { | |
4327 | if (cfq_cfqq_wait_request(cfqq) && !cfq_cfqq_must_alloc_slice(cfqq)) { | |
4328 | cfq_mark_cfqq_must_alloc_slice(cfqq); | |
4329 | return ELV_MQUEUE_MUST; | |
4330 | } | |
4331 | ||
4332 | return ELV_MQUEUE_MAY; | |
4333 | } | |
4334 | ||
4335 | static int cfq_may_queue(struct request_queue *q, unsigned int op) | |
4336 | { | |
4337 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
4338 | struct task_struct *tsk = current; | |
4339 | struct cfq_io_cq *cic; | |
4340 | struct cfq_queue *cfqq; | |
4341 | ||
4342 | /* | |
4343 | * don't force setup of a queue from here, as a call to may_queue | |
4344 | * does not necessarily imply that a request actually will be queued. | |
4345 | * so just lookup a possibly existing queue, or return 'may queue' | |
4346 | * if that fails | |
4347 | */ | |
4348 | cic = cfq_cic_lookup(cfqd, tsk->io_context); | |
4349 | if (!cic) | |
4350 | return ELV_MQUEUE_MAY; | |
4351 | ||
4352 | cfqq = cic_to_cfqq(cic, op_is_sync(op)); | |
4353 | if (cfqq) { | |
4354 | cfq_init_prio_data(cfqq, cic); | |
4355 | cfqq_boost_on_prio(cfqq, op); | |
4356 | ||
4357 | return __cfq_may_queue(cfqq); | |
4358 | } | |
4359 | ||
4360 | return ELV_MQUEUE_MAY; | |
4361 | } | |
4362 | ||
4363 | /* | |
4364 | * queue lock held here | |
4365 | */ | |
4366 | static void cfq_put_request(struct request *rq) | |
4367 | { | |
4368 | struct cfq_queue *cfqq = RQ_CFQQ(rq); | |
4369 | ||
4370 | if (cfqq) { | |
4371 | const int rw = rq_data_dir(rq); | |
4372 | ||
4373 | BUG_ON(!cfqq->allocated[rw]); | |
4374 | cfqq->allocated[rw]--; | |
4375 | ||
4376 | /* Put down rq reference on cfqg */ | |
4377 | cfqg_put(RQ_CFQG(rq)); | |
4378 | rq->elv.priv[0] = NULL; | |
4379 | rq->elv.priv[1] = NULL; | |
4380 | ||
4381 | cfq_put_queue(cfqq); | |
4382 | } | |
4383 | } | |
4384 | ||
4385 | static struct cfq_queue * | |
4386 | cfq_merge_cfqqs(struct cfq_data *cfqd, struct cfq_io_cq *cic, | |
4387 | struct cfq_queue *cfqq) | |
4388 | { | |
4389 | cfq_log_cfqq(cfqd, cfqq, "merging with queue %p", cfqq->new_cfqq); | |
4390 | cic_set_cfqq(cic, cfqq->new_cfqq, 1); | |
4391 | cfq_mark_cfqq_coop(cfqq->new_cfqq); | |
4392 | cfq_put_queue(cfqq); | |
4393 | return cic_to_cfqq(cic, 1); | |
4394 | } | |
4395 | ||
4396 | /* | |
4397 | * Returns NULL if a new cfqq should be allocated, or the old cfqq if this | |
4398 | * was the last process referring to said cfqq. | |
4399 | */ | |
4400 | static struct cfq_queue * | |
4401 | split_cfqq(struct cfq_io_cq *cic, struct cfq_queue *cfqq) | |
4402 | { | |
4403 | if (cfqq_process_refs(cfqq) == 1) { | |
4404 | cfqq->pid = current->pid; | |
4405 | cfq_clear_cfqq_coop(cfqq); | |
4406 | cfq_clear_cfqq_split_coop(cfqq); | |
4407 | return cfqq; | |
4408 | } | |
4409 | ||
4410 | cic_set_cfqq(cic, NULL, 1); | |
4411 | ||
4412 | cfq_put_cooperator(cfqq); | |
4413 | ||
4414 | cfq_put_queue(cfqq); | |
4415 | return NULL; | |
4416 | } | |
4417 | /* | |
4418 | * Allocate cfq data structures associated with this request. | |
4419 | */ | |
4420 | static int | |
4421 | cfq_set_request(struct request_queue *q, struct request *rq, struct bio *bio, | |
4422 | gfp_t gfp_mask) | |
4423 | { | |
4424 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
4425 | struct cfq_io_cq *cic = icq_to_cic(rq->elv.icq); | |
4426 | const int rw = rq_data_dir(rq); | |
4427 | const bool is_sync = rq_is_sync(rq); | |
4428 | struct cfq_queue *cfqq; | |
4429 | ||
4430 | spin_lock_irq(q->queue_lock); | |
4431 | ||
4432 | check_ioprio_changed(cic, bio); | |
4433 | check_blkcg_changed(cic, bio); | |
4434 | new_queue: | |
4435 | cfqq = cic_to_cfqq(cic, is_sync); | |
4436 | if (!cfqq || cfqq == &cfqd->oom_cfqq) { | |
4437 | if (cfqq) | |
4438 | cfq_put_queue(cfqq); | |
4439 | cfqq = cfq_get_queue(cfqd, is_sync, cic, bio); | |
4440 | cic_set_cfqq(cic, cfqq, is_sync); | |
4441 | } else { | |
4442 | /* | |
4443 | * If the queue was seeky for too long, break it apart. | |
4444 | */ | |
4445 | if (cfq_cfqq_coop(cfqq) && cfq_cfqq_split_coop(cfqq)) { | |
4446 | cfq_log_cfqq(cfqd, cfqq, "breaking apart cfqq"); | |
4447 | cfqq = split_cfqq(cic, cfqq); | |
4448 | if (!cfqq) | |
4449 | goto new_queue; | |
4450 | } | |
4451 | ||
4452 | /* | |
4453 | * Check to see if this queue is scheduled to merge with | |
4454 | * another, closely cooperating queue. The merging of | |
4455 | * queues happens here as it must be done in process context. | |
4456 | * The reference on new_cfqq was taken in merge_cfqqs. | |
4457 | */ | |
4458 | if (cfqq->new_cfqq) | |
4459 | cfqq = cfq_merge_cfqqs(cfqd, cic, cfqq); | |
4460 | } | |
4461 | ||
4462 | cfqq->allocated[rw]++; | |
4463 | ||
4464 | cfqq->ref++; | |
4465 | cfqg_get(cfqq->cfqg); | |
4466 | rq->elv.priv[0] = cfqq; | |
4467 | rq->elv.priv[1] = cfqq->cfqg; | |
4468 | spin_unlock_irq(q->queue_lock); | |
4469 | ||
4470 | return 0; | |
4471 | } | |
4472 | ||
4473 | static void cfq_kick_queue(struct work_struct *work) | |
4474 | { | |
4475 | struct cfq_data *cfqd = | |
4476 | container_of(work, struct cfq_data, unplug_work); | |
4477 | struct request_queue *q = cfqd->queue; | |
4478 | ||
4479 | spin_lock_irq(q->queue_lock); | |
4480 | __blk_run_queue(cfqd->queue); | |
4481 | spin_unlock_irq(q->queue_lock); | |
4482 | } | |
4483 | ||
4484 | /* | |
4485 | * Timer running if the active_queue is currently idling inside its time slice | |
4486 | */ | |
4487 | static enum hrtimer_restart cfq_idle_slice_timer(struct hrtimer *timer) | |
4488 | { | |
4489 | struct cfq_data *cfqd = container_of(timer, struct cfq_data, | |
4490 | idle_slice_timer); | |
4491 | struct cfq_queue *cfqq; | |
4492 | unsigned long flags; | |
4493 | int timed_out = 1; | |
4494 | ||
4495 | cfq_log(cfqd, "idle timer fired"); | |
4496 | ||
4497 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
4498 | ||
4499 | cfqq = cfqd->active_queue; | |
4500 | if (cfqq) { | |
4501 | timed_out = 0; | |
4502 | ||
4503 | /* | |
4504 | * We saw a request before the queue expired, let it through | |
4505 | */ | |
4506 | if (cfq_cfqq_must_dispatch(cfqq)) | |
4507 | goto out_kick; | |
4508 | ||
4509 | /* | |
4510 | * expired | |
4511 | */ | |
4512 | if (cfq_slice_used(cfqq)) | |
4513 | goto expire; | |
4514 | ||
4515 | /* | |
4516 | * only expire and reinvoke request handler, if there are | |
4517 | * other queues with pending requests | |
4518 | */ | |
4519 | if (!cfqd->busy_queues) | |
4520 | goto out_cont; | |
4521 | ||
4522 | /* | |
4523 | * not expired and it has a request pending, let it dispatch | |
4524 | */ | |
4525 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) | |
4526 | goto out_kick; | |
4527 | ||
4528 | /* | |
4529 | * Queue depth flag is reset only when the idle didn't succeed | |
4530 | */ | |
4531 | cfq_clear_cfqq_deep(cfqq); | |
4532 | } | |
4533 | expire: | |
4534 | cfq_slice_expired(cfqd, timed_out); | |
4535 | out_kick: | |
4536 | cfq_schedule_dispatch(cfqd); | |
4537 | out_cont: | |
4538 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
4539 | return HRTIMER_NORESTART; | |
4540 | } | |
4541 | ||
4542 | static void cfq_shutdown_timer_wq(struct cfq_data *cfqd) | |
4543 | { | |
4544 | hrtimer_cancel(&cfqd->idle_slice_timer); | |
4545 | cancel_work_sync(&cfqd->unplug_work); | |
4546 | } | |
4547 | ||
4548 | static void cfq_exit_queue(struct elevator_queue *e) | |
4549 | { | |
4550 | struct cfq_data *cfqd = e->elevator_data; | |
4551 | struct request_queue *q = cfqd->queue; | |
4552 | ||
4553 | cfq_shutdown_timer_wq(cfqd); | |
4554 | ||
4555 | spin_lock_irq(q->queue_lock); | |
4556 | ||
4557 | if (cfqd->active_queue) | |
4558 | __cfq_slice_expired(cfqd, cfqd->active_queue, 0); | |
4559 | ||
4560 | spin_unlock_irq(q->queue_lock); | |
4561 | ||
4562 | cfq_shutdown_timer_wq(cfqd); | |
4563 | ||
4564 | #ifdef CONFIG_CFQ_GROUP_IOSCHED | |
4565 | blkcg_deactivate_policy(q, &blkcg_policy_cfq); | |
4566 | #else | |
4567 | kfree(cfqd->root_group); | |
4568 | #endif | |
4569 | kfree(cfqd); | |
4570 | } | |
4571 | ||
4572 | static int cfq_init_queue(struct request_queue *q, struct elevator_type *e) | |
4573 | { | |
4574 | struct cfq_data *cfqd; | |
4575 | struct blkcg_gq *blkg __maybe_unused; | |
4576 | int i, ret; | |
4577 | struct elevator_queue *eq; | |
4578 | ||
4579 | eq = elevator_alloc(q, e); | |
4580 | if (!eq) | |
4581 | return -ENOMEM; | |
4582 | ||
4583 | cfqd = kzalloc_node(sizeof(*cfqd), GFP_KERNEL, q->node); | |
4584 | if (!cfqd) { | |
4585 | kobject_put(&eq->kobj); | |
4586 | return -ENOMEM; | |
4587 | } | |
4588 | eq->elevator_data = cfqd; | |
4589 | ||
4590 | cfqd->queue = q; | |
4591 | spin_lock_irq(q->queue_lock); | |
4592 | q->elevator = eq; | |
4593 | spin_unlock_irq(q->queue_lock); | |
4594 | ||
4595 | /* Init root service tree */ | |
4596 | cfqd->grp_service_tree = CFQ_RB_ROOT; | |
4597 | ||
4598 | /* Init root group and prefer root group over other groups by default */ | |
4599 | #ifdef CONFIG_CFQ_GROUP_IOSCHED | |
4600 | ret = blkcg_activate_policy(q, &blkcg_policy_cfq); | |
4601 | if (ret) | |
4602 | goto out_free; | |
4603 | ||
4604 | cfqd->root_group = blkg_to_cfqg(q->root_blkg); | |
4605 | #else | |
4606 | ret = -ENOMEM; | |
4607 | cfqd->root_group = kzalloc_node(sizeof(*cfqd->root_group), | |
4608 | GFP_KERNEL, cfqd->queue->node); | |
4609 | if (!cfqd->root_group) | |
4610 | goto out_free; | |
4611 | ||
4612 | cfq_init_cfqg_base(cfqd->root_group); | |
4613 | cfqd->root_group->weight = 2 * CFQ_WEIGHT_LEGACY_DFL; | |
4614 | cfqd->root_group->leaf_weight = 2 * CFQ_WEIGHT_LEGACY_DFL; | |
4615 | #endif | |
4616 | ||
4617 | /* | |
4618 | * Not strictly needed (since RB_ROOT just clears the node and we | |
4619 | * zeroed cfqd on alloc), but better be safe in case someone decides | |
4620 | * to add magic to the rb code | |
4621 | */ | |
4622 | for (i = 0; i < CFQ_PRIO_LISTS; i++) | |
4623 | cfqd->prio_trees[i] = RB_ROOT; | |
4624 | ||
4625 | /* | |
4626 | * Our fallback cfqq if cfq_get_queue() runs into OOM issues. | |
4627 | * Grab a permanent reference to it, so that the normal code flow | |
4628 | * will not attempt to free it. oom_cfqq is linked to root_group | |
4629 | * but shouldn't hold a reference as it'll never be unlinked. Lose | |
4630 | * the reference from linking right away. | |
4631 | */ | |
4632 | cfq_init_cfqq(cfqd, &cfqd->oom_cfqq, 1, 0); | |
4633 | cfqd->oom_cfqq.ref++; | |
4634 | ||
4635 | spin_lock_irq(q->queue_lock); | |
4636 | cfq_link_cfqq_cfqg(&cfqd->oom_cfqq, cfqd->root_group); | |
4637 | cfqg_put(cfqd->root_group); | |
4638 | spin_unlock_irq(q->queue_lock); | |
4639 | ||
4640 | hrtimer_init(&cfqd->idle_slice_timer, CLOCK_MONOTONIC, | |
4641 | HRTIMER_MODE_REL); | |
4642 | cfqd->idle_slice_timer.function = cfq_idle_slice_timer; | |
4643 | ||
4644 | INIT_WORK(&cfqd->unplug_work, cfq_kick_queue); | |
4645 | ||
4646 | cfqd->cfq_quantum = cfq_quantum; | |
4647 | cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; | |
4648 | cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; | |
4649 | cfqd->cfq_back_max = cfq_back_max; | |
4650 | cfqd->cfq_back_penalty = cfq_back_penalty; | |
4651 | cfqd->cfq_slice[0] = cfq_slice_async; | |
4652 | cfqd->cfq_slice[1] = cfq_slice_sync; | |
4653 | cfqd->cfq_target_latency = cfq_target_latency; | |
4654 | cfqd->cfq_slice_async_rq = cfq_slice_async_rq; | |
4655 | cfqd->cfq_slice_idle = cfq_slice_idle; | |
4656 | cfqd->cfq_group_idle = cfq_group_idle; | |
4657 | cfqd->cfq_latency = 1; | |
4658 | cfqd->hw_tag = -1; | |
4659 | /* | |
4660 | * we optimistically start assuming sync ops weren't delayed in last | |
4661 | * second, in order to have larger depth for async operations. | |
4662 | */ | |
4663 | cfqd->last_delayed_sync = ktime_get_ns() - NSEC_PER_SEC; | |
4664 | return 0; | |
4665 | ||
4666 | out_free: | |
4667 | kfree(cfqd); | |
4668 | kobject_put(&eq->kobj); | |
4669 | return ret; | |
4670 | } | |
4671 | ||
4672 | static void cfq_registered_queue(struct request_queue *q) | |
4673 | { | |
4674 | struct elevator_queue *e = q->elevator; | |
4675 | struct cfq_data *cfqd = e->elevator_data; | |
4676 | ||
4677 | /* | |
4678 | * Default to IOPS mode with no idling for SSDs | |
4679 | */ | |
4680 | if (blk_queue_nonrot(q)) | |
4681 | cfqd->cfq_slice_idle = 0; | |
4682 | wbt_disable_default(q); | |
4683 | } | |
4684 | ||
4685 | /* | |
4686 | * sysfs parts below --> | |
4687 | */ | |
4688 | static ssize_t | |
4689 | cfq_var_show(unsigned int var, char *page) | |
4690 | { | |
4691 | return sprintf(page, "%u\n", var); | |
4692 | } | |
4693 | ||
4694 | static void | |
4695 | cfq_var_store(unsigned int *var, const char *page) | |
4696 | { | |
4697 | char *p = (char *) page; | |
4698 | ||
4699 | *var = simple_strtoul(p, &p, 10); | |
4700 | } | |
4701 | ||
4702 | #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ | |
4703 | static ssize_t __FUNC(struct elevator_queue *e, char *page) \ | |
4704 | { \ | |
4705 | struct cfq_data *cfqd = e->elevator_data; \ | |
4706 | u64 __data = __VAR; \ | |
4707 | if (__CONV) \ | |
4708 | __data = div_u64(__data, NSEC_PER_MSEC); \ | |
4709 | return cfq_var_show(__data, (page)); \ | |
4710 | } | |
4711 | SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); | |
4712 | SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1); | |
4713 | SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1); | |
4714 | SHOW_FUNCTION(cfq_back_seek_max_show, cfqd->cfq_back_max, 0); | |
4715 | SHOW_FUNCTION(cfq_back_seek_penalty_show, cfqd->cfq_back_penalty, 0); | |
4716 | SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1); | |
4717 | SHOW_FUNCTION(cfq_group_idle_show, cfqd->cfq_group_idle, 1); | |
4718 | SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1); | |
4719 | SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1); | |
4720 | SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0); | |
4721 | SHOW_FUNCTION(cfq_low_latency_show, cfqd->cfq_latency, 0); | |
4722 | SHOW_FUNCTION(cfq_target_latency_show, cfqd->cfq_target_latency, 1); | |
4723 | #undef SHOW_FUNCTION | |
4724 | ||
4725 | #define USEC_SHOW_FUNCTION(__FUNC, __VAR) \ | |
4726 | static ssize_t __FUNC(struct elevator_queue *e, char *page) \ | |
4727 | { \ | |
4728 | struct cfq_data *cfqd = e->elevator_data; \ | |
4729 | u64 __data = __VAR; \ | |
4730 | __data = div_u64(__data, NSEC_PER_USEC); \ | |
4731 | return cfq_var_show(__data, (page)); \ | |
4732 | } | |
4733 | USEC_SHOW_FUNCTION(cfq_slice_idle_us_show, cfqd->cfq_slice_idle); | |
4734 | USEC_SHOW_FUNCTION(cfq_group_idle_us_show, cfqd->cfq_group_idle); | |
4735 | USEC_SHOW_FUNCTION(cfq_slice_sync_us_show, cfqd->cfq_slice[1]); | |
4736 | USEC_SHOW_FUNCTION(cfq_slice_async_us_show, cfqd->cfq_slice[0]); | |
4737 | USEC_SHOW_FUNCTION(cfq_target_latency_us_show, cfqd->cfq_target_latency); | |
4738 | #undef USEC_SHOW_FUNCTION | |
4739 | ||
4740 | #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ | |
4741 | static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \ | |
4742 | { \ | |
4743 | struct cfq_data *cfqd = e->elevator_data; \ | |
4744 | unsigned int __data; \ | |
4745 | cfq_var_store(&__data, (page)); \ | |
4746 | if (__data < (MIN)) \ | |
4747 | __data = (MIN); \ | |
4748 | else if (__data > (MAX)) \ | |
4749 | __data = (MAX); \ | |
4750 | if (__CONV) \ | |
4751 | *(__PTR) = (u64)__data * NSEC_PER_MSEC; \ | |
4752 | else \ | |
4753 | *(__PTR) = __data; \ | |
4754 | return count; \ | |
4755 | } | |
4756 | STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); | |
4757 | STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, | |
4758 | UINT_MAX, 1); | |
4759 | STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, | |
4760 | UINT_MAX, 1); | |
4761 | STORE_FUNCTION(cfq_back_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); | |
4762 | STORE_FUNCTION(cfq_back_seek_penalty_store, &cfqd->cfq_back_penalty, 1, | |
4763 | UINT_MAX, 0); | |
4764 | STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1); | |
4765 | STORE_FUNCTION(cfq_group_idle_store, &cfqd->cfq_group_idle, 0, UINT_MAX, 1); | |
4766 | STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1); | |
4767 | STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1); | |
4768 | STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, | |
4769 | UINT_MAX, 0); | |
4770 | STORE_FUNCTION(cfq_low_latency_store, &cfqd->cfq_latency, 0, 1, 0); | |
4771 | STORE_FUNCTION(cfq_target_latency_store, &cfqd->cfq_target_latency, 1, UINT_MAX, 1); | |
4772 | #undef STORE_FUNCTION | |
4773 | ||
4774 | #define USEC_STORE_FUNCTION(__FUNC, __PTR, MIN, MAX) \ | |
4775 | static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \ | |
4776 | { \ | |
4777 | struct cfq_data *cfqd = e->elevator_data; \ | |
4778 | unsigned int __data; \ | |
4779 | cfq_var_store(&__data, (page)); \ | |
4780 | if (__data < (MIN)) \ | |
4781 | __data = (MIN); \ | |
4782 | else if (__data > (MAX)) \ | |
4783 | __data = (MAX); \ | |
4784 | *(__PTR) = (u64)__data * NSEC_PER_USEC; \ | |
4785 | return count; \ | |
4786 | } | |
4787 | USEC_STORE_FUNCTION(cfq_slice_idle_us_store, &cfqd->cfq_slice_idle, 0, UINT_MAX); | |
4788 | USEC_STORE_FUNCTION(cfq_group_idle_us_store, &cfqd->cfq_group_idle, 0, UINT_MAX); | |
4789 | USEC_STORE_FUNCTION(cfq_slice_sync_us_store, &cfqd->cfq_slice[1], 1, UINT_MAX); | |
4790 | USEC_STORE_FUNCTION(cfq_slice_async_us_store, &cfqd->cfq_slice[0], 1, UINT_MAX); | |
4791 | USEC_STORE_FUNCTION(cfq_target_latency_us_store, &cfqd->cfq_target_latency, 1, UINT_MAX); | |
4792 | #undef USEC_STORE_FUNCTION | |
4793 | ||
4794 | #define CFQ_ATTR(name) \ | |
4795 | __ATTR(name, S_IRUGO|S_IWUSR, cfq_##name##_show, cfq_##name##_store) | |
4796 | ||
4797 | static struct elv_fs_entry cfq_attrs[] = { | |
4798 | CFQ_ATTR(quantum), | |
4799 | CFQ_ATTR(fifo_expire_sync), | |
4800 | CFQ_ATTR(fifo_expire_async), | |
4801 | CFQ_ATTR(back_seek_max), | |
4802 | CFQ_ATTR(back_seek_penalty), | |
4803 | CFQ_ATTR(slice_sync), | |
4804 | CFQ_ATTR(slice_sync_us), | |
4805 | CFQ_ATTR(slice_async), | |
4806 | CFQ_ATTR(slice_async_us), | |
4807 | CFQ_ATTR(slice_async_rq), | |
4808 | CFQ_ATTR(slice_idle), | |
4809 | CFQ_ATTR(slice_idle_us), | |
4810 | CFQ_ATTR(group_idle), | |
4811 | CFQ_ATTR(group_idle_us), | |
4812 | CFQ_ATTR(low_latency), | |
4813 | CFQ_ATTR(target_latency), | |
4814 | CFQ_ATTR(target_latency_us), | |
4815 | __ATTR_NULL | |
4816 | }; | |
4817 | ||
4818 | static struct elevator_type iosched_cfq = { | |
4819 | .ops.sq = { | |
4820 | .elevator_merge_fn = cfq_merge, | |
4821 | .elevator_merged_fn = cfq_merged_request, | |
4822 | .elevator_merge_req_fn = cfq_merged_requests, | |
4823 | .elevator_allow_bio_merge_fn = cfq_allow_bio_merge, | |
4824 | .elevator_allow_rq_merge_fn = cfq_allow_rq_merge, | |
4825 | .elevator_bio_merged_fn = cfq_bio_merged, | |
4826 | .elevator_dispatch_fn = cfq_dispatch_requests, | |
4827 | .elevator_add_req_fn = cfq_insert_request, | |
4828 | .elevator_activate_req_fn = cfq_activate_request, | |
4829 | .elevator_deactivate_req_fn = cfq_deactivate_request, | |
4830 | .elevator_completed_req_fn = cfq_completed_request, | |
4831 | .elevator_former_req_fn = elv_rb_former_request, | |
4832 | .elevator_latter_req_fn = elv_rb_latter_request, | |
4833 | .elevator_init_icq_fn = cfq_init_icq, | |
4834 | .elevator_exit_icq_fn = cfq_exit_icq, | |
4835 | .elevator_set_req_fn = cfq_set_request, | |
4836 | .elevator_put_req_fn = cfq_put_request, | |
4837 | .elevator_may_queue_fn = cfq_may_queue, | |
4838 | .elevator_init_fn = cfq_init_queue, | |
4839 | .elevator_exit_fn = cfq_exit_queue, | |
4840 | .elevator_registered_fn = cfq_registered_queue, | |
4841 | }, | |
4842 | .icq_size = sizeof(struct cfq_io_cq), | |
4843 | .icq_align = __alignof__(struct cfq_io_cq), | |
4844 | .elevator_attrs = cfq_attrs, | |
4845 | .elevator_name = "cfq", | |
4846 | .elevator_owner = THIS_MODULE, | |
4847 | }; | |
4848 | ||
4849 | #ifdef CONFIG_CFQ_GROUP_IOSCHED | |
4850 | static struct blkcg_policy blkcg_policy_cfq = { | |
4851 | .dfl_cftypes = cfq_blkcg_files, | |
4852 | .legacy_cftypes = cfq_blkcg_legacy_files, | |
4853 | ||
4854 | .cpd_alloc_fn = cfq_cpd_alloc, | |
4855 | .cpd_init_fn = cfq_cpd_init, | |
4856 | .cpd_free_fn = cfq_cpd_free, | |
4857 | .cpd_bind_fn = cfq_cpd_bind, | |
4858 | ||
4859 | .pd_alloc_fn = cfq_pd_alloc, | |
4860 | .pd_init_fn = cfq_pd_init, | |
4861 | .pd_offline_fn = cfq_pd_offline, | |
4862 | .pd_free_fn = cfq_pd_free, | |
4863 | .pd_reset_stats_fn = cfq_pd_reset_stats, | |
4864 | }; | |
4865 | #endif | |
4866 | ||
4867 | static int __init cfq_init(void) | |
4868 | { | |
4869 | int ret; | |
4870 | ||
4871 | #ifdef CONFIG_CFQ_GROUP_IOSCHED | |
4872 | ret = blkcg_policy_register(&blkcg_policy_cfq); | |
4873 | if (ret) | |
4874 | return ret; | |
4875 | #else | |
4876 | cfq_group_idle = 0; | |
4877 | #endif | |
4878 | ||
4879 | ret = -ENOMEM; | |
4880 | cfq_pool = KMEM_CACHE(cfq_queue, 0); | |
4881 | if (!cfq_pool) | |
4882 | goto err_pol_unreg; | |
4883 | ||
4884 | ret = elv_register(&iosched_cfq); | |
4885 | if (ret) | |
4886 | goto err_free_pool; | |
4887 | ||
4888 | return 0; | |
4889 | ||
4890 | err_free_pool: | |
4891 | kmem_cache_destroy(cfq_pool); | |
4892 | err_pol_unreg: | |
4893 | #ifdef CONFIG_CFQ_GROUP_IOSCHED | |
4894 | blkcg_policy_unregister(&blkcg_policy_cfq); | |
4895 | #endif | |
4896 | return ret; | |
4897 | } | |
4898 | ||
4899 | static void __exit cfq_exit(void) | |
4900 | { | |
4901 | #ifdef CONFIG_CFQ_GROUP_IOSCHED | |
4902 | blkcg_policy_unregister(&blkcg_policy_cfq); | |
4903 | #endif | |
4904 | elv_unregister(&iosched_cfq); | |
4905 | kmem_cache_destroy(cfq_pool); | |
4906 | } | |
4907 | ||
4908 | module_init(cfq_init); | |
4909 | module_exit(cfq_exit); | |
4910 | ||
4911 | MODULE_AUTHOR("Jens Axboe"); | |
4912 | MODULE_LICENSE("GPL"); | |
4913 | MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler"); |