Commit | Line | Data |
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1da177e4 | 1 | /* |
1da177e4 LT |
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 | * | |
0fe23479 | 7 | * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk> |
1da177e4 | 8 | */ |
1da177e4 | 9 | #include <linux/module.h> |
5a0e3ad6 | 10 | #include <linux/slab.h> |
1cc9be68 AV |
11 | #include <linux/blkdev.h> |
12 | #include <linux/elevator.h> | |
ad5ebd2f | 13 | #include <linux/jiffies.h> |
1da177e4 | 14 | #include <linux/rbtree.h> |
22e2c507 | 15 | #include <linux/ioprio.h> |
7b679138 | 16 | #include <linux/blktrace_api.h> |
6e736be7 | 17 | #include "blk.h" |
e98ef89b | 18 | #include "cfq.h" |
1da177e4 LT |
19 | |
20 | /* | |
21 | * tunables | |
22 | */ | |
fe094d98 | 23 | /* max queue in one round of service */ |
abc3c744 | 24 | static const int cfq_quantum = 8; |
64100099 | 25 | static const int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 }; |
fe094d98 JA |
26 | /* maximum backwards seek, in KiB */ |
27 | static const int cfq_back_max = 16 * 1024; | |
28 | /* penalty of a backwards seek */ | |
29 | static const int cfq_back_penalty = 2; | |
64100099 | 30 | static const int cfq_slice_sync = HZ / 10; |
3b18152c | 31 | static int cfq_slice_async = HZ / 25; |
64100099 | 32 | static const int cfq_slice_async_rq = 2; |
caaa5f9f | 33 | static int cfq_slice_idle = HZ / 125; |
80bdf0c7 | 34 | static int cfq_group_idle = HZ / 125; |
5db5d642 CZ |
35 | static const int cfq_target_latency = HZ * 3/10; /* 300 ms */ |
36 | static const int cfq_hist_divisor = 4; | |
22e2c507 | 37 | |
d9e7620e | 38 | /* |
0871714e | 39 | * offset from end of service tree |
d9e7620e | 40 | */ |
0871714e | 41 | #define CFQ_IDLE_DELAY (HZ / 5) |
d9e7620e JA |
42 | |
43 | /* | |
44 | * below this threshold, we consider thinktime immediate | |
45 | */ | |
46 | #define CFQ_MIN_TT (2) | |
47 | ||
22e2c507 | 48 | #define CFQ_SLICE_SCALE (5) |
45333d5a | 49 | #define CFQ_HW_QUEUE_MIN (5) |
25bc6b07 | 50 | #define CFQ_SERVICE_SHIFT 12 |
22e2c507 | 51 | |
3dde36dd | 52 | #define CFQQ_SEEK_THR (sector_t)(8 * 100) |
e9ce335d | 53 | #define CFQQ_CLOSE_THR (sector_t)(8 * 1024) |
41647e7a | 54 | #define CFQQ_SECT_THR_NONROT (sector_t)(2 * 32) |
3dde36dd | 55 | #define CFQQ_SEEKY(cfqq) (hweight32(cfqq->seek_history) > 32/8) |
ae54abed | 56 | |
a612fddf TH |
57 | #define RQ_CIC(rq) icq_to_cic((rq)->elv.icq) |
58 | #define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elv.priv[0]) | |
59 | #define RQ_CFQG(rq) (struct cfq_group *) ((rq)->elv.priv[1]) | |
1da177e4 | 60 | |
e18b890b | 61 | static struct kmem_cache *cfq_pool; |
1da177e4 | 62 | |
22e2c507 JA |
63 | #define CFQ_PRIO_LISTS IOPRIO_BE_NR |
64 | #define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE) | |
22e2c507 JA |
65 | #define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT) |
66 | ||
206dc69b | 67 | #define sample_valid(samples) ((samples) > 80) |
1fa8f6d6 | 68 | #define rb_entry_cfqg(node) rb_entry((node), struct cfq_group, rb_node) |
206dc69b | 69 | |
c5869807 TH |
70 | struct cfq_ttime { |
71 | unsigned long last_end_request; | |
72 | ||
73 | unsigned long ttime_total; | |
74 | unsigned long ttime_samples; | |
75 | unsigned long ttime_mean; | |
76 | }; | |
77 | ||
cc09e299 JA |
78 | /* |
79 | * Most of our rbtree usage is for sorting with min extraction, so | |
80 | * if we cache the leftmost node we don't have to walk down the tree | |
81 | * to find it. Idea borrowed from Ingo Molnars CFS scheduler. We should | |
82 | * move this into the elevator for the rq sorting as well. | |
83 | */ | |
84 | struct cfq_rb_root { | |
85 | struct rb_root rb; | |
86 | struct rb_node *left; | |
aa6f6a3d | 87 | unsigned count; |
73e9ffdd | 88 | unsigned total_weight; |
1fa8f6d6 | 89 | u64 min_vdisktime; |
f5f2b6ce | 90 | struct cfq_ttime ttime; |
cc09e299 | 91 | }; |
f5f2b6ce SL |
92 | #define CFQ_RB_ROOT (struct cfq_rb_root) { .rb = RB_ROOT, \ |
93 | .ttime = {.last_end_request = jiffies,},} | |
cc09e299 | 94 | |
6118b70b JA |
95 | /* |
96 | * Per process-grouping structure | |
97 | */ | |
98 | struct cfq_queue { | |
99 | /* reference count */ | |
30d7b944 | 100 | int ref; |
6118b70b JA |
101 | /* various state flags, see below */ |
102 | unsigned int flags; | |
103 | /* parent cfq_data */ | |
104 | struct cfq_data *cfqd; | |
105 | /* service_tree member */ | |
106 | struct rb_node rb_node; | |
107 | /* service_tree key */ | |
108 | unsigned long rb_key; | |
109 | /* prio tree member */ | |
110 | struct rb_node p_node; | |
111 | /* prio tree root we belong to, if any */ | |
112 | struct rb_root *p_root; | |
113 | /* sorted list of pending requests */ | |
114 | struct rb_root sort_list; | |
115 | /* if fifo isn't expired, next request to serve */ | |
116 | struct request *next_rq; | |
117 | /* requests queued in sort_list */ | |
118 | int queued[2]; | |
119 | /* currently allocated requests */ | |
120 | int allocated[2]; | |
121 | /* fifo list of requests in sort_list */ | |
122 | struct list_head fifo; | |
123 | ||
dae739eb VG |
124 | /* time when queue got scheduled in to dispatch first request. */ |
125 | unsigned long dispatch_start; | |
f75edf2d | 126 | unsigned int allocated_slice; |
c4081ba5 | 127 | unsigned int slice_dispatch; |
dae739eb VG |
128 | /* time when first request from queue completed and slice started. */ |
129 | unsigned long slice_start; | |
6118b70b JA |
130 | unsigned long slice_end; |
131 | long slice_resid; | |
6118b70b | 132 | |
65299a3b CH |
133 | /* pending priority requests */ |
134 | int prio_pending; | |
6118b70b JA |
135 | /* number of requests that are on the dispatch list or inside driver */ |
136 | int dispatched; | |
137 | ||
138 | /* io prio of this group */ | |
139 | unsigned short ioprio, org_ioprio; | |
4aede84b | 140 | unsigned short ioprio_class; |
6118b70b | 141 | |
c4081ba5 RK |
142 | pid_t pid; |
143 | ||
3dde36dd | 144 | u32 seek_history; |
b2c18e1e JM |
145 | sector_t last_request_pos; |
146 | ||
aa6f6a3d | 147 | struct cfq_rb_root *service_tree; |
df5fe3e8 | 148 | struct cfq_queue *new_cfqq; |
cdb16e8f | 149 | struct cfq_group *cfqg; |
c4e7893e VG |
150 | /* Number of sectors dispatched from queue in single dispatch round */ |
151 | unsigned long nr_sectors; | |
6118b70b JA |
152 | }; |
153 | ||
c0324a02 | 154 | /* |
718eee05 | 155 | * First index in the service_trees. |
c0324a02 CZ |
156 | * IDLE is handled separately, so it has negative index |
157 | */ | |
158 | enum wl_prio_t { | |
c0324a02 | 159 | BE_WORKLOAD = 0, |
615f0259 VG |
160 | RT_WORKLOAD = 1, |
161 | IDLE_WORKLOAD = 2, | |
b4627321 | 162 | CFQ_PRIO_NR, |
c0324a02 CZ |
163 | }; |
164 | ||
718eee05 CZ |
165 | /* |
166 | * Second index in the service_trees. | |
167 | */ | |
168 | enum wl_type_t { | |
169 | ASYNC_WORKLOAD = 0, | |
170 | SYNC_NOIDLE_WORKLOAD = 1, | |
171 | SYNC_WORKLOAD = 2 | |
172 | }; | |
173 | ||
cdb16e8f VG |
174 | /* This is per cgroup per device grouping structure */ |
175 | struct cfq_group { | |
1fa8f6d6 VG |
176 | /* group service_tree member */ |
177 | struct rb_node rb_node; | |
178 | ||
179 | /* group service_tree key */ | |
180 | u64 vdisktime; | |
25bc6b07 | 181 | unsigned int weight; |
8184f93e JT |
182 | unsigned int new_weight; |
183 | bool needs_update; | |
1fa8f6d6 VG |
184 | |
185 | /* number of cfqq currently on this group */ | |
186 | int nr_cfqq; | |
187 | ||
cdb16e8f | 188 | /* |
4495a7d4 | 189 | * Per group busy queues average. Useful for workload slice calc. We |
b4627321 VG |
190 | * create the array for each prio class but at run time it is used |
191 | * only for RT and BE class and slot for IDLE class remains unused. | |
192 | * This is primarily done to avoid confusion and a gcc warning. | |
193 | */ | |
194 | unsigned int busy_queues_avg[CFQ_PRIO_NR]; | |
195 | /* | |
196 | * rr lists of queues with requests. We maintain service trees for | |
197 | * RT and BE classes. These trees are subdivided in subclasses | |
198 | * of SYNC, SYNC_NOIDLE and ASYNC based on workload type. For IDLE | |
199 | * class there is no subclassification and all the cfq queues go on | |
200 | * a single tree service_tree_idle. | |
cdb16e8f VG |
201 | * Counts are embedded in the cfq_rb_root |
202 | */ | |
203 | struct cfq_rb_root service_trees[2][3]; | |
204 | struct cfq_rb_root service_tree_idle; | |
dae739eb VG |
205 | |
206 | unsigned long saved_workload_slice; | |
207 | enum wl_type_t saved_workload; | |
208 | enum wl_prio_t saved_serving_prio; | |
25fb5169 VG |
209 | struct blkio_group blkg; |
210 | #ifdef CONFIG_CFQ_GROUP_IOSCHED | |
211 | struct hlist_node cfqd_node; | |
329a6781 | 212 | int ref; |
25fb5169 | 213 | #endif |
80bdf0c7 VG |
214 | /* number of requests that are on the dispatch list or inside driver */ |
215 | int dispatched; | |
7700fc4f | 216 | struct cfq_ttime ttime; |
cdb16e8f | 217 | }; |
718eee05 | 218 | |
c5869807 TH |
219 | struct cfq_io_cq { |
220 | struct io_cq icq; /* must be the first member */ | |
221 | struct cfq_queue *cfqq[2]; | |
222 | struct cfq_ttime ttime; | |
223 | }; | |
224 | ||
22e2c507 JA |
225 | /* |
226 | * Per block device queue structure | |
227 | */ | |
1da177e4 | 228 | struct cfq_data { |
165125e1 | 229 | struct request_queue *queue; |
1fa8f6d6 VG |
230 | /* Root service tree for cfq_groups */ |
231 | struct cfq_rb_root grp_service_tree; | |
cdb16e8f | 232 | struct cfq_group root_group; |
22e2c507 | 233 | |
c0324a02 CZ |
234 | /* |
235 | * The priority currently being served | |
22e2c507 | 236 | */ |
c0324a02 | 237 | enum wl_prio_t serving_prio; |
718eee05 CZ |
238 | enum wl_type_t serving_type; |
239 | unsigned long workload_expires; | |
cdb16e8f | 240 | struct cfq_group *serving_group; |
a36e71f9 JA |
241 | |
242 | /* | |
243 | * Each priority tree is sorted by next_request position. These | |
244 | * trees are used when determining if two or more queues are | |
245 | * interleaving requests (see cfq_close_cooperator). | |
246 | */ | |
247 | struct rb_root prio_trees[CFQ_PRIO_LISTS]; | |
248 | ||
22e2c507 | 249 | unsigned int busy_queues; |
ef8a41df | 250 | unsigned int busy_sync_queues; |
22e2c507 | 251 | |
53c583d2 CZ |
252 | int rq_in_driver; |
253 | int rq_in_flight[2]; | |
45333d5a AC |
254 | |
255 | /* | |
256 | * queue-depth detection | |
257 | */ | |
258 | int rq_queued; | |
25776e35 | 259 | int hw_tag; |
e459dd08 CZ |
260 | /* |
261 | * hw_tag can be | |
262 | * -1 => indeterminate, (cfq will behave as if NCQ is present, to allow better detection) | |
263 | * 1 => NCQ is present (hw_tag_est_depth is the estimated max depth) | |
264 | * 0 => no NCQ | |
265 | */ | |
266 | int hw_tag_est_depth; | |
267 | unsigned int hw_tag_samples; | |
1da177e4 | 268 | |
22e2c507 JA |
269 | /* |
270 | * idle window management | |
271 | */ | |
272 | struct timer_list idle_slice_timer; | |
23e018a1 | 273 | struct work_struct unplug_work; |
1da177e4 | 274 | |
22e2c507 | 275 | struct cfq_queue *active_queue; |
c5869807 | 276 | struct cfq_io_cq *active_cic; |
22e2c507 | 277 | |
c2dea2d1 VT |
278 | /* |
279 | * async queue for each priority case | |
280 | */ | |
281 | struct cfq_queue *async_cfqq[2][IOPRIO_BE_NR]; | |
282 | struct cfq_queue *async_idle_cfqq; | |
15c31be4 | 283 | |
6d048f53 | 284 | sector_t last_position; |
1da177e4 | 285 | |
1da177e4 LT |
286 | /* |
287 | * tunables, see top of file | |
288 | */ | |
289 | unsigned int cfq_quantum; | |
22e2c507 | 290 | unsigned int cfq_fifo_expire[2]; |
1da177e4 LT |
291 | unsigned int cfq_back_penalty; |
292 | unsigned int cfq_back_max; | |
22e2c507 JA |
293 | unsigned int cfq_slice[2]; |
294 | unsigned int cfq_slice_async_rq; | |
295 | unsigned int cfq_slice_idle; | |
80bdf0c7 | 296 | unsigned int cfq_group_idle; |
963b72fc | 297 | unsigned int cfq_latency; |
5bf14c07 | 298 | unsigned int cfq_target_latency; |
d9ff4187 | 299 | |
6118b70b JA |
300 | /* |
301 | * Fallback dummy cfqq for extreme OOM conditions | |
302 | */ | |
303 | struct cfq_queue oom_cfqq; | |
365722bb | 304 | |
573412b2 | 305 | unsigned long last_delayed_sync; |
25fb5169 VG |
306 | |
307 | /* List of cfq groups being managed on this device*/ | |
308 | struct hlist_head cfqg_list; | |
56edf7d7 VG |
309 | |
310 | /* Number of groups which are on blkcg->blkg_list */ | |
311 | unsigned int nr_blkcg_linked_grps; | |
1da177e4 LT |
312 | }; |
313 | ||
25fb5169 VG |
314 | static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd); |
315 | ||
cdb16e8f VG |
316 | static struct cfq_rb_root *service_tree_for(struct cfq_group *cfqg, |
317 | enum wl_prio_t prio, | |
65b32a57 | 318 | enum wl_type_t type) |
c0324a02 | 319 | { |
1fa8f6d6 VG |
320 | if (!cfqg) |
321 | return NULL; | |
322 | ||
c0324a02 | 323 | if (prio == IDLE_WORKLOAD) |
cdb16e8f | 324 | return &cfqg->service_tree_idle; |
c0324a02 | 325 | |
cdb16e8f | 326 | return &cfqg->service_trees[prio][type]; |
c0324a02 CZ |
327 | } |
328 | ||
3b18152c | 329 | enum cfqq_state_flags { |
b0b8d749 JA |
330 | CFQ_CFQQ_FLAG_on_rr = 0, /* on round-robin busy list */ |
331 | CFQ_CFQQ_FLAG_wait_request, /* waiting for a request */ | |
b029195d | 332 | CFQ_CFQQ_FLAG_must_dispatch, /* must be allowed a dispatch */ |
b0b8d749 | 333 | CFQ_CFQQ_FLAG_must_alloc_slice, /* per-slice must_alloc flag */ |
b0b8d749 JA |
334 | CFQ_CFQQ_FLAG_fifo_expire, /* FIFO checked in this slice */ |
335 | CFQ_CFQQ_FLAG_idle_window, /* slice idling enabled */ | |
336 | CFQ_CFQQ_FLAG_prio_changed, /* task priority has changed */ | |
44f7c160 | 337 | CFQ_CFQQ_FLAG_slice_new, /* no requests dispatched in slice */ |
91fac317 | 338 | CFQ_CFQQ_FLAG_sync, /* synchronous queue */ |
b3b6d040 | 339 | CFQ_CFQQ_FLAG_coop, /* cfqq is shared */ |
ae54abed | 340 | CFQ_CFQQ_FLAG_split_coop, /* shared cfqq will be splitted */ |
76280aff | 341 | CFQ_CFQQ_FLAG_deep, /* sync cfqq experienced large depth */ |
f75edf2d | 342 | CFQ_CFQQ_FLAG_wait_busy, /* Waiting for next request */ |
3b18152c JA |
343 | }; |
344 | ||
345 | #define CFQ_CFQQ_FNS(name) \ | |
346 | static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \ | |
347 | { \ | |
fe094d98 | 348 | (cfqq)->flags |= (1 << CFQ_CFQQ_FLAG_##name); \ |
3b18152c JA |
349 | } \ |
350 | static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \ | |
351 | { \ | |
fe094d98 | 352 | (cfqq)->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \ |
3b18152c JA |
353 | } \ |
354 | static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \ | |
355 | { \ | |
fe094d98 | 356 | return ((cfqq)->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \ |
3b18152c JA |
357 | } |
358 | ||
359 | CFQ_CFQQ_FNS(on_rr); | |
360 | CFQ_CFQQ_FNS(wait_request); | |
b029195d | 361 | CFQ_CFQQ_FNS(must_dispatch); |
3b18152c | 362 | CFQ_CFQQ_FNS(must_alloc_slice); |
3b18152c JA |
363 | CFQ_CFQQ_FNS(fifo_expire); |
364 | CFQ_CFQQ_FNS(idle_window); | |
365 | CFQ_CFQQ_FNS(prio_changed); | |
44f7c160 | 366 | CFQ_CFQQ_FNS(slice_new); |
91fac317 | 367 | CFQ_CFQQ_FNS(sync); |
a36e71f9 | 368 | CFQ_CFQQ_FNS(coop); |
ae54abed | 369 | CFQ_CFQQ_FNS(split_coop); |
76280aff | 370 | CFQ_CFQQ_FNS(deep); |
f75edf2d | 371 | CFQ_CFQQ_FNS(wait_busy); |
3b18152c JA |
372 | #undef CFQ_CFQQ_FNS |
373 | ||
afc24d49 | 374 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
2868ef7b VG |
375 | #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \ |
376 | blk_add_trace_msg((cfqd)->queue, "cfq%d%c %s " fmt, (cfqq)->pid, \ | |
377 | cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \ | |
4495a7d4 | 378 | blkg_path(&(cfqq)->cfqg->blkg), ##args) |
2868ef7b VG |
379 | |
380 | #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) \ | |
381 | blk_add_trace_msg((cfqd)->queue, "%s " fmt, \ | |
4495a7d4 | 382 | blkg_path(&(cfqg)->blkg), ##args) \ |
2868ef7b VG |
383 | |
384 | #else | |
7b679138 JA |
385 | #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \ |
386 | blk_add_trace_msg((cfqd)->queue, "cfq%d " fmt, (cfqq)->pid, ##args) | |
4495a7d4 | 387 | #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) do {} while (0) |
2868ef7b | 388 | #endif |
7b679138 JA |
389 | #define cfq_log(cfqd, fmt, args...) \ |
390 | blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args) | |
391 | ||
615f0259 VG |
392 | /* Traverses through cfq group service trees */ |
393 | #define for_each_cfqg_st(cfqg, i, j, st) \ | |
394 | for (i = 0; i <= IDLE_WORKLOAD; i++) \ | |
395 | for (j = 0, st = i < IDLE_WORKLOAD ? &cfqg->service_trees[i][j]\ | |
396 | : &cfqg->service_tree_idle; \ | |
397 | (i < IDLE_WORKLOAD && j <= SYNC_WORKLOAD) || \ | |
398 | (i == IDLE_WORKLOAD && j == 0); \ | |
399 | j++, st = i < IDLE_WORKLOAD ? \ | |
400 | &cfqg->service_trees[i][j]: NULL) \ | |
401 | ||
f5f2b6ce SL |
402 | static inline bool cfq_io_thinktime_big(struct cfq_data *cfqd, |
403 | struct cfq_ttime *ttime, bool group_idle) | |
404 | { | |
405 | unsigned long slice; | |
406 | if (!sample_valid(ttime->ttime_samples)) | |
407 | return false; | |
408 | if (group_idle) | |
409 | slice = cfqd->cfq_group_idle; | |
410 | else | |
411 | slice = cfqd->cfq_slice_idle; | |
412 | return ttime->ttime_mean > slice; | |
413 | } | |
615f0259 | 414 | |
02b35081 VG |
415 | static inline bool iops_mode(struct cfq_data *cfqd) |
416 | { | |
417 | /* | |
418 | * If we are not idling on queues and it is a NCQ drive, parallel | |
419 | * execution of requests is on and measuring time is not possible | |
420 | * in most of the cases until and unless we drive shallower queue | |
421 | * depths and that becomes a performance bottleneck. In such cases | |
422 | * switch to start providing fairness in terms of number of IOs. | |
423 | */ | |
424 | if (!cfqd->cfq_slice_idle && cfqd->hw_tag) | |
425 | return true; | |
426 | else | |
427 | return false; | |
428 | } | |
429 | ||
c0324a02 CZ |
430 | static inline enum wl_prio_t cfqq_prio(struct cfq_queue *cfqq) |
431 | { | |
432 | if (cfq_class_idle(cfqq)) | |
433 | return IDLE_WORKLOAD; | |
434 | if (cfq_class_rt(cfqq)) | |
435 | return RT_WORKLOAD; | |
436 | return BE_WORKLOAD; | |
437 | } | |
438 | ||
718eee05 CZ |
439 | |
440 | static enum wl_type_t cfqq_type(struct cfq_queue *cfqq) | |
441 | { | |
442 | if (!cfq_cfqq_sync(cfqq)) | |
443 | return ASYNC_WORKLOAD; | |
444 | if (!cfq_cfqq_idle_window(cfqq)) | |
445 | return SYNC_NOIDLE_WORKLOAD; | |
446 | return SYNC_WORKLOAD; | |
447 | } | |
448 | ||
58ff82f3 VG |
449 | static inline int cfq_group_busy_queues_wl(enum wl_prio_t wl, |
450 | struct cfq_data *cfqd, | |
451 | struct cfq_group *cfqg) | |
c0324a02 CZ |
452 | { |
453 | if (wl == IDLE_WORKLOAD) | |
cdb16e8f | 454 | return cfqg->service_tree_idle.count; |
c0324a02 | 455 | |
cdb16e8f VG |
456 | return cfqg->service_trees[wl][ASYNC_WORKLOAD].count |
457 | + cfqg->service_trees[wl][SYNC_NOIDLE_WORKLOAD].count | |
458 | + cfqg->service_trees[wl][SYNC_WORKLOAD].count; | |
c0324a02 CZ |
459 | } |
460 | ||
f26bd1f0 VG |
461 | static inline int cfqg_busy_async_queues(struct cfq_data *cfqd, |
462 | struct cfq_group *cfqg) | |
463 | { | |
464 | return cfqg->service_trees[RT_WORKLOAD][ASYNC_WORKLOAD].count | |
465 | + cfqg->service_trees[BE_WORKLOAD][ASYNC_WORKLOAD].count; | |
466 | } | |
467 | ||
165125e1 | 468 | static void cfq_dispatch_insert(struct request_queue *, struct request *); |
a6151c3a | 469 | static struct cfq_queue *cfq_get_queue(struct cfq_data *, bool, |
fd0928df | 470 | struct io_context *, gfp_t); |
91fac317 | 471 | |
c5869807 TH |
472 | static inline struct cfq_io_cq *icq_to_cic(struct io_cq *icq) |
473 | { | |
474 | /* cic->icq is the first member, %NULL will convert to %NULL */ | |
475 | return container_of(icq, struct cfq_io_cq, icq); | |
476 | } | |
477 | ||
47fdd4ca TH |
478 | static inline struct cfq_io_cq *cfq_cic_lookup(struct cfq_data *cfqd, |
479 | struct io_context *ioc) | |
480 | { | |
481 | if (ioc) | |
482 | return icq_to_cic(ioc_lookup_icq(ioc, cfqd->queue)); | |
483 | return NULL; | |
484 | } | |
485 | ||
c5869807 | 486 | static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_cq *cic, bool is_sync) |
91fac317 | 487 | { |
a6151c3a | 488 | return cic->cfqq[is_sync]; |
91fac317 VT |
489 | } |
490 | ||
c5869807 TH |
491 | static inline void cic_set_cfqq(struct cfq_io_cq *cic, struct cfq_queue *cfqq, |
492 | bool is_sync) | |
91fac317 | 493 | { |
a6151c3a | 494 | cic->cfqq[is_sync] = cfqq; |
91fac317 VT |
495 | } |
496 | ||
c5869807 | 497 | static inline struct cfq_data *cic_to_cfqd(struct cfq_io_cq *cic) |
bca4b914 | 498 | { |
c5869807 | 499 | return cic->icq.q->elevator->elevator_data; |
bca4b914 KK |
500 | } |
501 | ||
91fac317 VT |
502 | /* |
503 | * We regard a request as SYNC, if it's either a read or has the SYNC bit | |
504 | * set (in which case it could also be direct WRITE). | |
505 | */ | |
a6151c3a | 506 | static inline bool cfq_bio_sync(struct bio *bio) |
91fac317 | 507 | { |
7b6d91da | 508 | return bio_data_dir(bio) == READ || (bio->bi_rw & REQ_SYNC); |
91fac317 | 509 | } |
1da177e4 | 510 | |
99f95e52 AM |
511 | /* |
512 | * scheduler run of queue, if there are requests pending and no one in the | |
513 | * driver that will restart queueing | |
514 | */ | |
23e018a1 | 515 | static inline void cfq_schedule_dispatch(struct cfq_data *cfqd) |
99f95e52 | 516 | { |
7b679138 JA |
517 | if (cfqd->busy_queues) { |
518 | cfq_log(cfqd, "schedule dispatch"); | |
23e018a1 | 519 | kblockd_schedule_work(cfqd->queue, &cfqd->unplug_work); |
7b679138 | 520 | } |
99f95e52 AM |
521 | } |
522 | ||
44f7c160 JA |
523 | /* |
524 | * Scale schedule slice based on io priority. Use the sync time slice only | |
525 | * if a queue is marked sync and has sync io queued. A sync queue with async | |
526 | * io only, should not get full sync slice length. | |
527 | */ | |
a6151c3a | 528 | static inline int cfq_prio_slice(struct cfq_data *cfqd, bool sync, |
d9e7620e | 529 | unsigned short prio) |
44f7c160 | 530 | { |
d9e7620e | 531 | const int base_slice = cfqd->cfq_slice[sync]; |
44f7c160 | 532 | |
d9e7620e JA |
533 | WARN_ON(prio >= IOPRIO_BE_NR); |
534 | ||
535 | return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - prio)); | |
536 | } | |
44f7c160 | 537 | |
d9e7620e JA |
538 | static inline int |
539 | cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
540 | { | |
541 | return cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio); | |
44f7c160 JA |
542 | } |
543 | ||
25bc6b07 VG |
544 | static inline u64 cfq_scale_slice(unsigned long delta, struct cfq_group *cfqg) |
545 | { | |
546 | u64 d = delta << CFQ_SERVICE_SHIFT; | |
547 | ||
548 | d = d * BLKIO_WEIGHT_DEFAULT; | |
549 | do_div(d, cfqg->weight); | |
550 | return d; | |
551 | } | |
552 | ||
553 | static inline u64 max_vdisktime(u64 min_vdisktime, u64 vdisktime) | |
554 | { | |
555 | s64 delta = (s64)(vdisktime - min_vdisktime); | |
556 | if (delta > 0) | |
557 | min_vdisktime = vdisktime; | |
558 | ||
559 | return min_vdisktime; | |
560 | } | |
561 | ||
562 | static inline u64 min_vdisktime(u64 min_vdisktime, u64 vdisktime) | |
563 | { | |
564 | s64 delta = (s64)(vdisktime - min_vdisktime); | |
565 | if (delta < 0) | |
566 | min_vdisktime = vdisktime; | |
567 | ||
568 | return min_vdisktime; | |
569 | } | |
570 | ||
571 | static void update_min_vdisktime(struct cfq_rb_root *st) | |
572 | { | |
25bc6b07 VG |
573 | struct cfq_group *cfqg; |
574 | ||
25bc6b07 VG |
575 | if (st->left) { |
576 | cfqg = rb_entry_cfqg(st->left); | |
a6032710 GJ |
577 | st->min_vdisktime = max_vdisktime(st->min_vdisktime, |
578 | cfqg->vdisktime); | |
25bc6b07 | 579 | } |
25bc6b07 VG |
580 | } |
581 | ||
5db5d642 CZ |
582 | /* |
583 | * get averaged number of queues of RT/BE priority. | |
584 | * average is updated, with a formula that gives more weight to higher numbers, | |
585 | * to quickly follows sudden increases and decrease slowly | |
586 | */ | |
587 | ||
58ff82f3 VG |
588 | static inline unsigned cfq_group_get_avg_queues(struct cfq_data *cfqd, |
589 | struct cfq_group *cfqg, bool rt) | |
5869619c | 590 | { |
5db5d642 CZ |
591 | unsigned min_q, max_q; |
592 | unsigned mult = cfq_hist_divisor - 1; | |
593 | unsigned round = cfq_hist_divisor / 2; | |
58ff82f3 | 594 | unsigned busy = cfq_group_busy_queues_wl(rt, cfqd, cfqg); |
5db5d642 | 595 | |
58ff82f3 VG |
596 | min_q = min(cfqg->busy_queues_avg[rt], busy); |
597 | max_q = max(cfqg->busy_queues_avg[rt], busy); | |
598 | cfqg->busy_queues_avg[rt] = (mult * max_q + min_q + round) / | |
5db5d642 | 599 | cfq_hist_divisor; |
58ff82f3 VG |
600 | return cfqg->busy_queues_avg[rt]; |
601 | } | |
602 | ||
603 | static inline unsigned | |
604 | cfq_group_slice(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
605 | { | |
606 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
607 | ||
5bf14c07 | 608 | return cfqd->cfq_target_latency * cfqg->weight / st->total_weight; |
5db5d642 CZ |
609 | } |
610 | ||
c553f8e3 | 611 | static inline unsigned |
ba5bd520 | 612 | cfq_scaled_cfqq_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
44f7c160 | 613 | { |
5db5d642 CZ |
614 | unsigned slice = cfq_prio_to_slice(cfqd, cfqq); |
615 | if (cfqd->cfq_latency) { | |
58ff82f3 VG |
616 | /* |
617 | * interested queues (we consider only the ones with the same | |
618 | * priority class in the cfq group) | |
619 | */ | |
620 | unsigned iq = cfq_group_get_avg_queues(cfqd, cfqq->cfqg, | |
621 | cfq_class_rt(cfqq)); | |
5db5d642 CZ |
622 | unsigned sync_slice = cfqd->cfq_slice[1]; |
623 | unsigned expect_latency = sync_slice * iq; | |
58ff82f3 VG |
624 | unsigned group_slice = cfq_group_slice(cfqd, cfqq->cfqg); |
625 | ||
626 | if (expect_latency > group_slice) { | |
5db5d642 CZ |
627 | unsigned base_low_slice = 2 * cfqd->cfq_slice_idle; |
628 | /* scale low_slice according to IO priority | |
629 | * and sync vs async */ | |
630 | unsigned low_slice = | |
631 | min(slice, base_low_slice * slice / sync_slice); | |
632 | /* the adapted slice value is scaled to fit all iqs | |
633 | * into the target latency */ | |
58ff82f3 | 634 | slice = max(slice * group_slice / expect_latency, |
5db5d642 CZ |
635 | low_slice); |
636 | } | |
637 | } | |
c553f8e3 SL |
638 | return slice; |
639 | } | |
640 | ||
641 | static inline void | |
642 | cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
643 | { | |
ba5bd520 | 644 | unsigned slice = cfq_scaled_cfqq_slice(cfqd, cfqq); |
c553f8e3 | 645 | |
dae739eb | 646 | cfqq->slice_start = jiffies; |
5db5d642 | 647 | cfqq->slice_end = jiffies + slice; |
f75edf2d | 648 | cfqq->allocated_slice = slice; |
7b679138 | 649 | cfq_log_cfqq(cfqd, cfqq, "set_slice=%lu", cfqq->slice_end - jiffies); |
44f7c160 JA |
650 | } |
651 | ||
652 | /* | |
653 | * We need to wrap this check in cfq_cfqq_slice_new(), since ->slice_end | |
654 | * isn't valid until the first request from the dispatch is activated | |
655 | * and the slice time set. | |
656 | */ | |
a6151c3a | 657 | static inline bool cfq_slice_used(struct cfq_queue *cfqq) |
44f7c160 JA |
658 | { |
659 | if (cfq_cfqq_slice_new(cfqq)) | |
c1e44756 | 660 | return false; |
44f7c160 | 661 | if (time_before(jiffies, cfqq->slice_end)) |
c1e44756 | 662 | return false; |
44f7c160 | 663 | |
c1e44756 | 664 | return true; |
44f7c160 JA |
665 | } |
666 | ||
1da177e4 | 667 | /* |
5e705374 | 668 | * Lifted from AS - choose which of rq1 and rq2 that is best served now. |
1da177e4 | 669 | * We choose the request that is closest to the head right now. Distance |
e8a99053 | 670 | * behind the head is penalized and only allowed to a certain extent. |
1da177e4 | 671 | */ |
5e705374 | 672 | static struct request * |
cf7c25cf | 673 | cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2, sector_t last) |
1da177e4 | 674 | { |
cf7c25cf | 675 | sector_t s1, s2, d1 = 0, d2 = 0; |
1da177e4 | 676 | unsigned long back_max; |
e8a99053 AM |
677 | #define CFQ_RQ1_WRAP 0x01 /* request 1 wraps */ |
678 | #define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */ | |
679 | unsigned wrap = 0; /* bit mask: requests behind the disk head? */ | |
1da177e4 | 680 | |
5e705374 JA |
681 | if (rq1 == NULL || rq1 == rq2) |
682 | return rq2; | |
683 | if (rq2 == NULL) | |
684 | return rq1; | |
9c2c38a1 | 685 | |
229836bd NK |
686 | if (rq_is_sync(rq1) != rq_is_sync(rq2)) |
687 | return rq_is_sync(rq1) ? rq1 : rq2; | |
688 | ||
65299a3b CH |
689 | if ((rq1->cmd_flags ^ rq2->cmd_flags) & REQ_PRIO) |
690 | return rq1->cmd_flags & REQ_PRIO ? rq1 : rq2; | |
b53d1ed7 | 691 | |
83096ebf TH |
692 | s1 = blk_rq_pos(rq1); |
693 | s2 = blk_rq_pos(rq2); | |
1da177e4 | 694 | |
1da177e4 LT |
695 | /* |
696 | * by definition, 1KiB is 2 sectors | |
697 | */ | |
698 | back_max = cfqd->cfq_back_max * 2; | |
699 | ||
700 | /* | |
701 | * Strict one way elevator _except_ in the case where we allow | |
702 | * short backward seeks which are biased as twice the cost of a | |
703 | * similar forward seek. | |
704 | */ | |
705 | if (s1 >= last) | |
706 | d1 = s1 - last; | |
707 | else if (s1 + back_max >= last) | |
708 | d1 = (last - s1) * cfqd->cfq_back_penalty; | |
709 | else | |
e8a99053 | 710 | wrap |= CFQ_RQ1_WRAP; |
1da177e4 LT |
711 | |
712 | if (s2 >= last) | |
713 | d2 = s2 - last; | |
714 | else if (s2 + back_max >= last) | |
715 | d2 = (last - s2) * cfqd->cfq_back_penalty; | |
716 | else | |
e8a99053 | 717 | wrap |= CFQ_RQ2_WRAP; |
1da177e4 LT |
718 | |
719 | /* Found required data */ | |
e8a99053 AM |
720 | |
721 | /* | |
722 | * By doing switch() on the bit mask "wrap" we avoid having to | |
723 | * check two variables for all permutations: --> faster! | |
724 | */ | |
725 | switch (wrap) { | |
5e705374 | 726 | case 0: /* common case for CFQ: rq1 and rq2 not wrapped */ |
e8a99053 | 727 | if (d1 < d2) |
5e705374 | 728 | return rq1; |
e8a99053 | 729 | else if (d2 < d1) |
5e705374 | 730 | return rq2; |
e8a99053 AM |
731 | else { |
732 | if (s1 >= s2) | |
5e705374 | 733 | return rq1; |
e8a99053 | 734 | else |
5e705374 | 735 | return rq2; |
e8a99053 | 736 | } |
1da177e4 | 737 | |
e8a99053 | 738 | case CFQ_RQ2_WRAP: |
5e705374 | 739 | return rq1; |
e8a99053 | 740 | case CFQ_RQ1_WRAP: |
5e705374 JA |
741 | return rq2; |
742 | case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both rqs wrapped */ | |
e8a99053 AM |
743 | default: |
744 | /* | |
745 | * Since both rqs are wrapped, | |
746 | * start with the one that's further behind head | |
747 | * (--> only *one* back seek required), | |
748 | * since back seek takes more time than forward. | |
749 | */ | |
750 | if (s1 <= s2) | |
5e705374 | 751 | return rq1; |
1da177e4 | 752 | else |
5e705374 | 753 | return rq2; |
1da177e4 LT |
754 | } |
755 | } | |
756 | ||
498d3aa2 JA |
757 | /* |
758 | * The below is leftmost cache rbtree addon | |
759 | */ | |
0871714e | 760 | static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root) |
cc09e299 | 761 | { |
615f0259 VG |
762 | /* Service tree is empty */ |
763 | if (!root->count) | |
764 | return NULL; | |
765 | ||
cc09e299 JA |
766 | if (!root->left) |
767 | root->left = rb_first(&root->rb); | |
768 | ||
0871714e JA |
769 | if (root->left) |
770 | return rb_entry(root->left, struct cfq_queue, rb_node); | |
771 | ||
772 | return NULL; | |
cc09e299 JA |
773 | } |
774 | ||
1fa8f6d6 VG |
775 | static struct cfq_group *cfq_rb_first_group(struct cfq_rb_root *root) |
776 | { | |
777 | if (!root->left) | |
778 | root->left = rb_first(&root->rb); | |
779 | ||
780 | if (root->left) | |
781 | return rb_entry_cfqg(root->left); | |
782 | ||
783 | return NULL; | |
784 | } | |
785 | ||
a36e71f9 JA |
786 | static void rb_erase_init(struct rb_node *n, struct rb_root *root) |
787 | { | |
788 | rb_erase(n, root); | |
789 | RB_CLEAR_NODE(n); | |
790 | } | |
791 | ||
cc09e299 JA |
792 | static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root) |
793 | { | |
794 | if (root->left == n) | |
795 | root->left = NULL; | |
a36e71f9 | 796 | rb_erase_init(n, &root->rb); |
aa6f6a3d | 797 | --root->count; |
cc09e299 JA |
798 | } |
799 | ||
1da177e4 LT |
800 | /* |
801 | * would be nice to take fifo expire time into account as well | |
802 | */ | |
5e705374 JA |
803 | static struct request * |
804 | cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
805 | struct request *last) | |
1da177e4 | 806 | { |
21183b07 JA |
807 | struct rb_node *rbnext = rb_next(&last->rb_node); |
808 | struct rb_node *rbprev = rb_prev(&last->rb_node); | |
5e705374 | 809 | struct request *next = NULL, *prev = NULL; |
1da177e4 | 810 | |
21183b07 | 811 | BUG_ON(RB_EMPTY_NODE(&last->rb_node)); |
1da177e4 LT |
812 | |
813 | if (rbprev) | |
5e705374 | 814 | prev = rb_entry_rq(rbprev); |
1da177e4 | 815 | |
21183b07 | 816 | if (rbnext) |
5e705374 | 817 | next = rb_entry_rq(rbnext); |
21183b07 JA |
818 | else { |
819 | rbnext = rb_first(&cfqq->sort_list); | |
820 | if (rbnext && rbnext != &last->rb_node) | |
5e705374 | 821 | next = rb_entry_rq(rbnext); |
21183b07 | 822 | } |
1da177e4 | 823 | |
cf7c25cf | 824 | return cfq_choose_req(cfqd, next, prev, blk_rq_pos(last)); |
1da177e4 LT |
825 | } |
826 | ||
d9e7620e JA |
827 | static unsigned long cfq_slice_offset(struct cfq_data *cfqd, |
828 | struct cfq_queue *cfqq) | |
1da177e4 | 829 | { |
d9e7620e JA |
830 | /* |
831 | * just an approximation, should be ok. | |
832 | */ | |
cdb16e8f | 833 | return (cfqq->cfqg->nr_cfqq - 1) * (cfq_prio_slice(cfqd, 1, 0) - |
464191c6 | 834 | cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio)); |
d9e7620e JA |
835 | } |
836 | ||
1fa8f6d6 VG |
837 | static inline s64 |
838 | cfqg_key(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
839 | { | |
840 | return cfqg->vdisktime - st->min_vdisktime; | |
841 | } | |
842 | ||
843 | static void | |
844 | __cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
845 | { | |
846 | struct rb_node **node = &st->rb.rb_node; | |
847 | struct rb_node *parent = NULL; | |
848 | struct cfq_group *__cfqg; | |
849 | s64 key = cfqg_key(st, cfqg); | |
850 | int left = 1; | |
851 | ||
852 | while (*node != NULL) { | |
853 | parent = *node; | |
854 | __cfqg = rb_entry_cfqg(parent); | |
855 | ||
856 | if (key < cfqg_key(st, __cfqg)) | |
857 | node = &parent->rb_left; | |
858 | else { | |
859 | node = &parent->rb_right; | |
860 | left = 0; | |
861 | } | |
862 | } | |
863 | ||
864 | if (left) | |
865 | st->left = &cfqg->rb_node; | |
866 | ||
867 | rb_link_node(&cfqg->rb_node, parent, node); | |
868 | rb_insert_color(&cfqg->rb_node, &st->rb); | |
869 | } | |
870 | ||
871 | static void | |
8184f93e JT |
872 | cfq_update_group_weight(struct cfq_group *cfqg) |
873 | { | |
874 | BUG_ON(!RB_EMPTY_NODE(&cfqg->rb_node)); | |
875 | if (cfqg->needs_update) { | |
876 | cfqg->weight = cfqg->new_weight; | |
877 | cfqg->needs_update = false; | |
878 | } | |
879 | } | |
880 | ||
881 | static void | |
882 | cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
883 | { | |
884 | BUG_ON(!RB_EMPTY_NODE(&cfqg->rb_node)); | |
885 | ||
886 | cfq_update_group_weight(cfqg); | |
887 | __cfq_group_service_tree_add(st, cfqg); | |
888 | st->total_weight += cfqg->weight; | |
889 | } | |
890 | ||
891 | static void | |
892 | cfq_group_notify_queue_add(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
1fa8f6d6 VG |
893 | { |
894 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
895 | struct cfq_group *__cfqg; | |
896 | struct rb_node *n; | |
897 | ||
898 | cfqg->nr_cfqq++; | |
760701bf | 899 | if (!RB_EMPTY_NODE(&cfqg->rb_node)) |
1fa8f6d6 VG |
900 | return; |
901 | ||
902 | /* | |
903 | * Currently put the group at the end. Later implement something | |
904 | * so that groups get lesser vtime based on their weights, so that | |
25985edc | 905 | * if group does not loose all if it was not continuously backlogged. |
1fa8f6d6 VG |
906 | */ |
907 | n = rb_last(&st->rb); | |
908 | if (n) { | |
909 | __cfqg = rb_entry_cfqg(n); | |
910 | cfqg->vdisktime = __cfqg->vdisktime + CFQ_IDLE_DELAY; | |
911 | } else | |
912 | cfqg->vdisktime = st->min_vdisktime; | |
8184f93e JT |
913 | cfq_group_service_tree_add(st, cfqg); |
914 | } | |
1fa8f6d6 | 915 | |
8184f93e JT |
916 | static void |
917 | cfq_group_service_tree_del(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
918 | { | |
919 | st->total_weight -= cfqg->weight; | |
920 | if (!RB_EMPTY_NODE(&cfqg->rb_node)) | |
921 | cfq_rb_erase(&cfqg->rb_node, st); | |
1fa8f6d6 VG |
922 | } |
923 | ||
924 | static void | |
8184f93e | 925 | cfq_group_notify_queue_del(struct cfq_data *cfqd, struct cfq_group *cfqg) |
1fa8f6d6 VG |
926 | { |
927 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
928 | ||
929 | BUG_ON(cfqg->nr_cfqq < 1); | |
930 | cfqg->nr_cfqq--; | |
25bc6b07 | 931 | |
1fa8f6d6 VG |
932 | /* If there are other cfq queues under this group, don't delete it */ |
933 | if (cfqg->nr_cfqq) | |
934 | return; | |
935 | ||
2868ef7b | 936 | cfq_log_cfqg(cfqd, cfqg, "del_from_rr group"); |
8184f93e | 937 | cfq_group_service_tree_del(st, cfqg); |
dae739eb | 938 | cfqg->saved_workload_slice = 0; |
e98ef89b | 939 | cfq_blkiocg_update_dequeue_stats(&cfqg->blkg, 1); |
dae739eb VG |
940 | } |
941 | ||
167400d3 JT |
942 | static inline unsigned int cfq_cfqq_slice_usage(struct cfq_queue *cfqq, |
943 | unsigned int *unaccounted_time) | |
dae739eb | 944 | { |
f75edf2d | 945 | unsigned int slice_used; |
dae739eb VG |
946 | |
947 | /* | |
948 | * Queue got expired before even a single request completed or | |
949 | * got expired immediately after first request completion. | |
950 | */ | |
951 | if (!cfqq->slice_start || cfqq->slice_start == jiffies) { | |
952 | /* | |
953 | * Also charge the seek time incurred to the group, otherwise | |
954 | * if there are mutiple queues in the group, each can dispatch | |
955 | * a single request on seeky media and cause lots of seek time | |
956 | * and group will never know it. | |
957 | */ | |
958 | slice_used = max_t(unsigned, (jiffies - cfqq->dispatch_start), | |
959 | 1); | |
960 | } else { | |
961 | slice_used = jiffies - cfqq->slice_start; | |
167400d3 JT |
962 | if (slice_used > cfqq->allocated_slice) { |
963 | *unaccounted_time = slice_used - cfqq->allocated_slice; | |
f75edf2d | 964 | slice_used = cfqq->allocated_slice; |
167400d3 JT |
965 | } |
966 | if (time_after(cfqq->slice_start, cfqq->dispatch_start)) | |
967 | *unaccounted_time += cfqq->slice_start - | |
968 | cfqq->dispatch_start; | |
dae739eb VG |
969 | } |
970 | ||
dae739eb VG |
971 | return slice_used; |
972 | } | |
973 | ||
974 | static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg, | |
e5ff082e | 975 | struct cfq_queue *cfqq) |
dae739eb VG |
976 | { |
977 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
167400d3 | 978 | unsigned int used_sl, charge, unaccounted_sl = 0; |
f26bd1f0 VG |
979 | int nr_sync = cfqg->nr_cfqq - cfqg_busy_async_queues(cfqd, cfqg) |
980 | - cfqg->service_tree_idle.count; | |
981 | ||
982 | BUG_ON(nr_sync < 0); | |
167400d3 | 983 | used_sl = charge = cfq_cfqq_slice_usage(cfqq, &unaccounted_sl); |
dae739eb | 984 | |
02b35081 VG |
985 | if (iops_mode(cfqd)) |
986 | charge = cfqq->slice_dispatch; | |
987 | else if (!cfq_cfqq_sync(cfqq) && !nr_sync) | |
988 | charge = cfqq->allocated_slice; | |
dae739eb VG |
989 | |
990 | /* Can't update vdisktime while group is on service tree */ | |
8184f93e | 991 | cfq_group_service_tree_del(st, cfqg); |
02b35081 | 992 | cfqg->vdisktime += cfq_scale_slice(charge, cfqg); |
8184f93e JT |
993 | /* If a new weight was requested, update now, off tree */ |
994 | cfq_group_service_tree_add(st, cfqg); | |
dae739eb VG |
995 | |
996 | /* This group is being expired. Save the context */ | |
997 | if (time_after(cfqd->workload_expires, jiffies)) { | |
998 | cfqg->saved_workload_slice = cfqd->workload_expires | |
999 | - jiffies; | |
1000 | cfqg->saved_workload = cfqd->serving_type; | |
1001 | cfqg->saved_serving_prio = cfqd->serving_prio; | |
1002 | } else | |
1003 | cfqg->saved_workload_slice = 0; | |
2868ef7b VG |
1004 | |
1005 | cfq_log_cfqg(cfqd, cfqg, "served: vt=%llu min_vt=%llu", cfqg->vdisktime, | |
1006 | st->min_vdisktime); | |
fd16d263 JP |
1007 | cfq_log_cfqq(cfqq->cfqd, cfqq, |
1008 | "sl_used=%u disp=%u charge=%u iops=%u sect=%lu", | |
1009 | used_sl, cfqq->slice_dispatch, charge, | |
1010 | iops_mode(cfqd), cfqq->nr_sectors); | |
167400d3 JT |
1011 | cfq_blkiocg_update_timeslice_used(&cfqg->blkg, used_sl, |
1012 | unaccounted_sl); | |
e98ef89b | 1013 | cfq_blkiocg_set_start_empty_time(&cfqg->blkg); |
1fa8f6d6 VG |
1014 | } |
1015 | ||
25fb5169 VG |
1016 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
1017 | static inline struct cfq_group *cfqg_of_blkg(struct blkio_group *blkg) | |
1018 | { | |
1019 | if (blkg) | |
1020 | return container_of(blkg, struct cfq_group, blkg); | |
1021 | return NULL; | |
1022 | } | |
1023 | ||
8aea4545 PB |
1024 | static void cfq_update_blkio_group_weight(void *key, struct blkio_group *blkg, |
1025 | unsigned int weight) | |
f8d461d6 | 1026 | { |
8184f93e JT |
1027 | struct cfq_group *cfqg = cfqg_of_blkg(blkg); |
1028 | cfqg->new_weight = weight; | |
1029 | cfqg->needs_update = true; | |
f8d461d6 VG |
1030 | } |
1031 | ||
f469a7b4 VG |
1032 | static void cfq_init_add_cfqg_lists(struct cfq_data *cfqd, |
1033 | struct cfq_group *cfqg, struct blkio_cgroup *blkcg) | |
25fb5169 | 1034 | { |
22084190 VG |
1035 | struct backing_dev_info *bdi = &cfqd->queue->backing_dev_info; |
1036 | unsigned int major, minor; | |
25fb5169 | 1037 | |
f469a7b4 VG |
1038 | /* |
1039 | * Add group onto cgroup list. It might happen that bdi->dev is | |
1040 | * not initialized yet. Initialize this new group without major | |
1041 | * and minor info and this info will be filled in once a new thread | |
1042 | * comes for IO. | |
1043 | */ | |
1044 | if (bdi->dev) { | |
a74b2ada | 1045 | sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor); |
f469a7b4 VG |
1046 | cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg, |
1047 | (void *)cfqd, MKDEV(major, minor)); | |
1048 | } else | |
1049 | cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg, | |
1050 | (void *)cfqd, 0); | |
1051 | ||
1052 | cfqd->nr_blkcg_linked_grps++; | |
1053 | cfqg->weight = blkcg_get_weight(blkcg, cfqg->blkg.dev); | |
1054 | ||
1055 | /* Add group on cfqd list */ | |
1056 | hlist_add_head(&cfqg->cfqd_node, &cfqd->cfqg_list); | |
1057 | } | |
1058 | ||
1059 | /* | |
1060 | * Should be called from sleepable context. No request queue lock as per | |
1061 | * cpu stats are allocated dynamically and alloc_percpu needs to be called | |
1062 | * from sleepable context. | |
1063 | */ | |
1064 | static struct cfq_group * cfq_alloc_cfqg(struct cfq_data *cfqd) | |
1065 | { | |
1066 | struct cfq_group *cfqg = NULL; | |
5624a4e4 | 1067 | int i, j, ret; |
f469a7b4 | 1068 | struct cfq_rb_root *st; |
25fb5169 VG |
1069 | |
1070 | cfqg = kzalloc_node(sizeof(*cfqg), GFP_ATOMIC, cfqd->queue->node); | |
1071 | if (!cfqg) | |
f469a7b4 | 1072 | return NULL; |
25fb5169 | 1073 | |
25fb5169 VG |
1074 | for_each_cfqg_st(cfqg, i, j, st) |
1075 | *st = CFQ_RB_ROOT; | |
1076 | RB_CLEAR_NODE(&cfqg->rb_node); | |
1077 | ||
7700fc4f SL |
1078 | cfqg->ttime.last_end_request = jiffies; |
1079 | ||
b1c35769 VG |
1080 | /* |
1081 | * Take the initial reference that will be released on destroy | |
1082 | * This can be thought of a joint reference by cgroup and | |
1083 | * elevator which will be dropped by either elevator exit | |
1084 | * or cgroup deletion path depending on who is exiting first. | |
1085 | */ | |
329a6781 | 1086 | cfqg->ref = 1; |
5624a4e4 VG |
1087 | |
1088 | ret = blkio_alloc_blkg_stats(&cfqg->blkg); | |
1089 | if (ret) { | |
1090 | kfree(cfqg); | |
1091 | return NULL; | |
1092 | } | |
1093 | ||
f469a7b4 VG |
1094 | return cfqg; |
1095 | } | |
1096 | ||
1097 | static struct cfq_group * | |
1098 | cfq_find_cfqg(struct cfq_data *cfqd, struct blkio_cgroup *blkcg) | |
1099 | { | |
1100 | struct cfq_group *cfqg = NULL; | |
1101 | void *key = cfqd; | |
1102 | struct backing_dev_info *bdi = &cfqd->queue->backing_dev_info; | |
1103 | unsigned int major, minor; | |
b1c35769 | 1104 | |
180be2a0 | 1105 | /* |
f469a7b4 VG |
1106 | * This is the common case when there are no blkio cgroups. |
1107 | * Avoid lookup in this case | |
180be2a0 | 1108 | */ |
f469a7b4 VG |
1109 | if (blkcg == &blkio_root_cgroup) |
1110 | cfqg = &cfqd->root_group; | |
1111 | else | |
1112 | cfqg = cfqg_of_blkg(blkiocg_lookup_group(blkcg, key)); | |
25fb5169 | 1113 | |
f469a7b4 VG |
1114 | if (cfqg && !cfqg->blkg.dev && bdi->dev && dev_name(bdi->dev)) { |
1115 | sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor); | |
1116 | cfqg->blkg.dev = MKDEV(major, minor); | |
1117 | } | |
25fb5169 | 1118 | |
25fb5169 VG |
1119 | return cfqg; |
1120 | } | |
1121 | ||
1122 | /* | |
3e59cf9d VG |
1123 | * Search for the cfq group current task belongs to. request_queue lock must |
1124 | * be held. | |
25fb5169 | 1125 | */ |
3e59cf9d | 1126 | static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd) |
25fb5169 | 1127 | { |
70087dc3 | 1128 | struct blkio_cgroup *blkcg; |
f469a7b4 VG |
1129 | struct cfq_group *cfqg = NULL, *__cfqg = NULL; |
1130 | struct request_queue *q = cfqd->queue; | |
25fb5169 VG |
1131 | |
1132 | rcu_read_lock(); | |
70087dc3 | 1133 | blkcg = task_blkio_cgroup(current); |
f469a7b4 VG |
1134 | cfqg = cfq_find_cfqg(cfqd, blkcg); |
1135 | if (cfqg) { | |
1136 | rcu_read_unlock(); | |
1137 | return cfqg; | |
1138 | } | |
1139 | ||
1140 | /* | |
1141 | * Need to allocate a group. Allocation of group also needs allocation | |
1142 | * of per cpu stats which in-turn takes a mutex() and can block. Hence | |
1143 | * we need to drop rcu lock and queue_lock before we call alloc. | |
1144 | * | |
1145 | * Not taking any queue reference here and assuming that queue is | |
1146 | * around by the time we return. CFQ queue allocation code does | |
1147 | * the same. It might be racy though. | |
1148 | */ | |
1149 | ||
1150 | rcu_read_unlock(); | |
1151 | spin_unlock_irq(q->queue_lock); | |
1152 | ||
1153 | cfqg = cfq_alloc_cfqg(cfqd); | |
1154 | ||
1155 | spin_lock_irq(q->queue_lock); | |
1156 | ||
1157 | rcu_read_lock(); | |
1158 | blkcg = task_blkio_cgroup(current); | |
1159 | ||
1160 | /* | |
1161 | * If some other thread already allocated the group while we were | |
1162 | * not holding queue lock, free up the group | |
1163 | */ | |
1164 | __cfqg = cfq_find_cfqg(cfqd, blkcg); | |
1165 | ||
1166 | if (__cfqg) { | |
1167 | kfree(cfqg); | |
1168 | rcu_read_unlock(); | |
1169 | return __cfqg; | |
1170 | } | |
1171 | ||
3e59cf9d | 1172 | if (!cfqg) |
25fb5169 | 1173 | cfqg = &cfqd->root_group; |
f469a7b4 VG |
1174 | |
1175 | cfq_init_add_cfqg_lists(cfqd, cfqg, blkcg); | |
25fb5169 VG |
1176 | rcu_read_unlock(); |
1177 | return cfqg; | |
1178 | } | |
1179 | ||
7f1dc8a2 VG |
1180 | static inline struct cfq_group *cfq_ref_get_cfqg(struct cfq_group *cfqg) |
1181 | { | |
329a6781 | 1182 | cfqg->ref++; |
7f1dc8a2 VG |
1183 | return cfqg; |
1184 | } | |
1185 | ||
25fb5169 VG |
1186 | static void cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) |
1187 | { | |
1188 | /* Currently, all async queues are mapped to root group */ | |
1189 | if (!cfq_cfqq_sync(cfqq)) | |
1190 | cfqg = &cfqq->cfqd->root_group; | |
1191 | ||
1192 | cfqq->cfqg = cfqg; | |
b1c35769 | 1193 | /* cfqq reference on cfqg */ |
329a6781 | 1194 | cfqq->cfqg->ref++; |
b1c35769 VG |
1195 | } |
1196 | ||
1197 | static void cfq_put_cfqg(struct cfq_group *cfqg) | |
1198 | { | |
1199 | struct cfq_rb_root *st; | |
1200 | int i, j; | |
1201 | ||
329a6781 SL |
1202 | BUG_ON(cfqg->ref <= 0); |
1203 | cfqg->ref--; | |
1204 | if (cfqg->ref) | |
b1c35769 VG |
1205 | return; |
1206 | for_each_cfqg_st(cfqg, i, j, st) | |
b54ce60e | 1207 | BUG_ON(!RB_EMPTY_ROOT(&st->rb)); |
5624a4e4 | 1208 | free_percpu(cfqg->blkg.stats_cpu); |
b1c35769 VG |
1209 | kfree(cfqg); |
1210 | } | |
1211 | ||
1212 | static void cfq_destroy_cfqg(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
1213 | { | |
1214 | /* Something wrong if we are trying to remove same group twice */ | |
1215 | BUG_ON(hlist_unhashed(&cfqg->cfqd_node)); | |
1216 | ||
1217 | hlist_del_init(&cfqg->cfqd_node); | |
1218 | ||
a5395b83 VG |
1219 | BUG_ON(cfqd->nr_blkcg_linked_grps <= 0); |
1220 | cfqd->nr_blkcg_linked_grps--; | |
1221 | ||
b1c35769 VG |
1222 | /* |
1223 | * Put the reference taken at the time of creation so that when all | |
1224 | * queues are gone, group can be destroyed. | |
1225 | */ | |
1226 | cfq_put_cfqg(cfqg); | |
1227 | } | |
1228 | ||
1229 | static void cfq_release_cfq_groups(struct cfq_data *cfqd) | |
1230 | { | |
1231 | struct hlist_node *pos, *n; | |
1232 | struct cfq_group *cfqg; | |
1233 | ||
1234 | hlist_for_each_entry_safe(cfqg, pos, n, &cfqd->cfqg_list, cfqd_node) { | |
1235 | /* | |
1236 | * If cgroup removal path got to blk_group first and removed | |
1237 | * it from cgroup list, then it will take care of destroying | |
1238 | * cfqg also. | |
1239 | */ | |
e98ef89b | 1240 | if (!cfq_blkiocg_del_blkio_group(&cfqg->blkg)) |
b1c35769 VG |
1241 | cfq_destroy_cfqg(cfqd, cfqg); |
1242 | } | |
25fb5169 | 1243 | } |
b1c35769 VG |
1244 | |
1245 | /* | |
1246 | * Blk cgroup controller notification saying that blkio_group object is being | |
1247 | * delinked as associated cgroup object is going away. That also means that | |
1248 | * no new IO will come in this group. So get rid of this group as soon as | |
1249 | * any pending IO in the group is finished. | |
1250 | * | |
1251 | * This function is called under rcu_read_lock(). key is the rcu protected | |
1252 | * pointer. That means "key" is a valid cfq_data pointer as long as we are rcu | |
1253 | * read lock. | |
1254 | * | |
1255 | * "key" was fetched from blkio_group under blkio_cgroup->lock. That means | |
1256 | * it should not be NULL as even if elevator was exiting, cgroup deltion | |
1257 | * path got to it first. | |
1258 | */ | |
8aea4545 | 1259 | static void cfq_unlink_blkio_group(void *key, struct blkio_group *blkg) |
b1c35769 VG |
1260 | { |
1261 | unsigned long flags; | |
1262 | struct cfq_data *cfqd = key; | |
1263 | ||
1264 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
1265 | cfq_destroy_cfqg(cfqd, cfqg_of_blkg(blkg)); | |
1266 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
1267 | } | |
1268 | ||
25fb5169 | 1269 | #else /* GROUP_IOSCHED */ |
3e59cf9d | 1270 | static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd) |
25fb5169 VG |
1271 | { |
1272 | return &cfqd->root_group; | |
1273 | } | |
7f1dc8a2 VG |
1274 | |
1275 | static inline struct cfq_group *cfq_ref_get_cfqg(struct cfq_group *cfqg) | |
1276 | { | |
50eaeb32 | 1277 | return cfqg; |
7f1dc8a2 VG |
1278 | } |
1279 | ||
25fb5169 VG |
1280 | static inline void |
1281 | cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) { | |
1282 | cfqq->cfqg = cfqg; | |
1283 | } | |
1284 | ||
b1c35769 VG |
1285 | static void cfq_release_cfq_groups(struct cfq_data *cfqd) {} |
1286 | static inline void cfq_put_cfqg(struct cfq_group *cfqg) {} | |
1287 | ||
25fb5169 VG |
1288 | #endif /* GROUP_IOSCHED */ |
1289 | ||
498d3aa2 | 1290 | /* |
c0324a02 | 1291 | * The cfqd->service_trees holds all pending cfq_queue's that have |
498d3aa2 JA |
1292 | * requests waiting to be processed. It is sorted in the order that |
1293 | * we will service the queues. | |
1294 | */ | |
a36e71f9 | 1295 | static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
a6151c3a | 1296 | bool add_front) |
d9e7620e | 1297 | { |
0871714e JA |
1298 | struct rb_node **p, *parent; |
1299 | struct cfq_queue *__cfqq; | |
d9e7620e | 1300 | unsigned long rb_key; |
c0324a02 | 1301 | struct cfq_rb_root *service_tree; |
498d3aa2 | 1302 | int left; |
dae739eb | 1303 | int new_cfqq = 1; |
ae30c286 | 1304 | |
cdb16e8f | 1305 | service_tree = service_tree_for(cfqq->cfqg, cfqq_prio(cfqq), |
65b32a57 | 1306 | cfqq_type(cfqq)); |
0871714e JA |
1307 | if (cfq_class_idle(cfqq)) { |
1308 | rb_key = CFQ_IDLE_DELAY; | |
aa6f6a3d | 1309 | parent = rb_last(&service_tree->rb); |
0871714e JA |
1310 | if (parent && parent != &cfqq->rb_node) { |
1311 | __cfqq = rb_entry(parent, struct cfq_queue, rb_node); | |
1312 | rb_key += __cfqq->rb_key; | |
1313 | } else | |
1314 | rb_key += jiffies; | |
1315 | } else if (!add_front) { | |
b9c8946b JA |
1316 | /* |
1317 | * Get our rb key offset. Subtract any residual slice | |
1318 | * value carried from last service. A negative resid | |
1319 | * count indicates slice overrun, and this should position | |
1320 | * the next service time further away in the tree. | |
1321 | */ | |
edd75ffd | 1322 | rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies; |
b9c8946b | 1323 | rb_key -= cfqq->slice_resid; |
edd75ffd | 1324 | cfqq->slice_resid = 0; |
48e025e6 CZ |
1325 | } else { |
1326 | rb_key = -HZ; | |
aa6f6a3d | 1327 | __cfqq = cfq_rb_first(service_tree); |
48e025e6 CZ |
1328 | rb_key += __cfqq ? __cfqq->rb_key : jiffies; |
1329 | } | |
1da177e4 | 1330 | |
d9e7620e | 1331 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) { |
dae739eb | 1332 | new_cfqq = 0; |
99f9628a | 1333 | /* |
d9e7620e | 1334 | * same position, nothing more to do |
99f9628a | 1335 | */ |
c0324a02 CZ |
1336 | if (rb_key == cfqq->rb_key && |
1337 | cfqq->service_tree == service_tree) | |
d9e7620e | 1338 | return; |
1da177e4 | 1339 | |
aa6f6a3d CZ |
1340 | cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree); |
1341 | cfqq->service_tree = NULL; | |
1da177e4 | 1342 | } |
d9e7620e | 1343 | |
498d3aa2 | 1344 | left = 1; |
0871714e | 1345 | parent = NULL; |
aa6f6a3d CZ |
1346 | cfqq->service_tree = service_tree; |
1347 | p = &service_tree->rb.rb_node; | |
d9e7620e | 1348 | while (*p) { |
67060e37 | 1349 | struct rb_node **n; |
cc09e299 | 1350 | |
d9e7620e JA |
1351 | parent = *p; |
1352 | __cfqq = rb_entry(parent, struct cfq_queue, rb_node); | |
1353 | ||
0c534e0a | 1354 | /* |
c0324a02 | 1355 | * sort by key, that represents service time. |
0c534e0a | 1356 | */ |
c0324a02 | 1357 | if (time_before(rb_key, __cfqq->rb_key)) |
67060e37 | 1358 | n = &(*p)->rb_left; |
c0324a02 | 1359 | else { |
67060e37 | 1360 | n = &(*p)->rb_right; |
cc09e299 | 1361 | left = 0; |
c0324a02 | 1362 | } |
67060e37 JA |
1363 | |
1364 | p = n; | |
d9e7620e JA |
1365 | } |
1366 | ||
cc09e299 | 1367 | if (left) |
aa6f6a3d | 1368 | service_tree->left = &cfqq->rb_node; |
cc09e299 | 1369 | |
d9e7620e JA |
1370 | cfqq->rb_key = rb_key; |
1371 | rb_link_node(&cfqq->rb_node, parent, p); | |
aa6f6a3d CZ |
1372 | rb_insert_color(&cfqq->rb_node, &service_tree->rb); |
1373 | service_tree->count++; | |
20359f27 | 1374 | if (add_front || !new_cfqq) |
dae739eb | 1375 | return; |
8184f93e | 1376 | cfq_group_notify_queue_add(cfqd, cfqq->cfqg); |
1da177e4 LT |
1377 | } |
1378 | ||
a36e71f9 | 1379 | static struct cfq_queue * |
f2d1f0ae JA |
1380 | cfq_prio_tree_lookup(struct cfq_data *cfqd, struct rb_root *root, |
1381 | sector_t sector, struct rb_node **ret_parent, | |
1382 | struct rb_node ***rb_link) | |
a36e71f9 | 1383 | { |
a36e71f9 JA |
1384 | struct rb_node **p, *parent; |
1385 | struct cfq_queue *cfqq = NULL; | |
1386 | ||
1387 | parent = NULL; | |
1388 | p = &root->rb_node; | |
1389 | while (*p) { | |
1390 | struct rb_node **n; | |
1391 | ||
1392 | parent = *p; | |
1393 | cfqq = rb_entry(parent, struct cfq_queue, p_node); | |
1394 | ||
1395 | /* | |
1396 | * Sort strictly based on sector. Smallest to the left, | |
1397 | * largest to the right. | |
1398 | */ | |
2e46e8b2 | 1399 | if (sector > blk_rq_pos(cfqq->next_rq)) |
a36e71f9 | 1400 | n = &(*p)->rb_right; |
2e46e8b2 | 1401 | else if (sector < blk_rq_pos(cfqq->next_rq)) |
a36e71f9 JA |
1402 | n = &(*p)->rb_left; |
1403 | else | |
1404 | break; | |
1405 | p = n; | |
3ac6c9f8 | 1406 | cfqq = NULL; |
a36e71f9 JA |
1407 | } |
1408 | ||
1409 | *ret_parent = parent; | |
1410 | if (rb_link) | |
1411 | *rb_link = p; | |
3ac6c9f8 | 1412 | return cfqq; |
a36e71f9 JA |
1413 | } |
1414 | ||
1415 | static void cfq_prio_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1416 | { | |
a36e71f9 JA |
1417 | struct rb_node **p, *parent; |
1418 | struct cfq_queue *__cfqq; | |
1419 | ||
f2d1f0ae JA |
1420 | if (cfqq->p_root) { |
1421 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
1422 | cfqq->p_root = NULL; | |
1423 | } | |
a36e71f9 JA |
1424 | |
1425 | if (cfq_class_idle(cfqq)) | |
1426 | return; | |
1427 | if (!cfqq->next_rq) | |
1428 | return; | |
1429 | ||
f2d1f0ae | 1430 | cfqq->p_root = &cfqd->prio_trees[cfqq->org_ioprio]; |
2e46e8b2 TH |
1431 | __cfqq = cfq_prio_tree_lookup(cfqd, cfqq->p_root, |
1432 | blk_rq_pos(cfqq->next_rq), &parent, &p); | |
3ac6c9f8 JA |
1433 | if (!__cfqq) { |
1434 | rb_link_node(&cfqq->p_node, parent, p); | |
f2d1f0ae JA |
1435 | rb_insert_color(&cfqq->p_node, cfqq->p_root); |
1436 | } else | |
1437 | cfqq->p_root = NULL; | |
a36e71f9 JA |
1438 | } |
1439 | ||
498d3aa2 JA |
1440 | /* |
1441 | * Update cfqq's position in the service tree. | |
1442 | */ | |
edd75ffd | 1443 | static void cfq_resort_rr_list(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
6d048f53 | 1444 | { |
6d048f53 JA |
1445 | /* |
1446 | * Resorting requires the cfqq to be on the RR list already. | |
1447 | */ | |
a36e71f9 | 1448 | if (cfq_cfqq_on_rr(cfqq)) { |
edd75ffd | 1449 | cfq_service_tree_add(cfqd, cfqq, 0); |
a36e71f9 JA |
1450 | cfq_prio_tree_add(cfqd, cfqq); |
1451 | } | |
6d048f53 JA |
1452 | } |
1453 | ||
1da177e4 LT |
1454 | /* |
1455 | * add to busy list of queues for service, trying to be fair in ordering | |
22e2c507 | 1456 | * the pending list according to last request service |
1da177e4 | 1457 | */ |
febffd61 | 1458 | static void cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 1459 | { |
7b679138 | 1460 | cfq_log_cfqq(cfqd, cfqq, "add_to_rr"); |
3b18152c JA |
1461 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
1462 | cfq_mark_cfqq_on_rr(cfqq); | |
1da177e4 | 1463 | cfqd->busy_queues++; |
ef8a41df SL |
1464 | if (cfq_cfqq_sync(cfqq)) |
1465 | cfqd->busy_sync_queues++; | |
1da177e4 | 1466 | |
edd75ffd | 1467 | cfq_resort_rr_list(cfqd, cfqq); |
1da177e4 LT |
1468 | } |
1469 | ||
498d3aa2 JA |
1470 | /* |
1471 | * Called when the cfqq no longer has requests pending, remove it from | |
1472 | * the service tree. | |
1473 | */ | |
febffd61 | 1474 | static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 1475 | { |
7b679138 | 1476 | cfq_log_cfqq(cfqd, cfqq, "del_from_rr"); |
3b18152c JA |
1477 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
1478 | cfq_clear_cfqq_on_rr(cfqq); | |
1da177e4 | 1479 | |
aa6f6a3d CZ |
1480 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) { |
1481 | cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree); | |
1482 | cfqq->service_tree = NULL; | |
1483 | } | |
f2d1f0ae JA |
1484 | if (cfqq->p_root) { |
1485 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
1486 | cfqq->p_root = NULL; | |
1487 | } | |
d9e7620e | 1488 | |
8184f93e | 1489 | cfq_group_notify_queue_del(cfqd, cfqq->cfqg); |
1da177e4 LT |
1490 | BUG_ON(!cfqd->busy_queues); |
1491 | cfqd->busy_queues--; | |
ef8a41df SL |
1492 | if (cfq_cfqq_sync(cfqq)) |
1493 | cfqd->busy_sync_queues--; | |
1da177e4 LT |
1494 | } |
1495 | ||
1496 | /* | |
1497 | * rb tree support functions | |
1498 | */ | |
febffd61 | 1499 | static void cfq_del_rq_rb(struct request *rq) |
1da177e4 | 1500 | { |
5e705374 | 1501 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
5e705374 | 1502 | const int sync = rq_is_sync(rq); |
1da177e4 | 1503 | |
b4878f24 JA |
1504 | BUG_ON(!cfqq->queued[sync]); |
1505 | cfqq->queued[sync]--; | |
1da177e4 | 1506 | |
5e705374 | 1507 | elv_rb_del(&cfqq->sort_list, rq); |
1da177e4 | 1508 | |
f04a6424 VG |
1509 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) { |
1510 | /* | |
1511 | * Queue will be deleted from service tree when we actually | |
1512 | * expire it later. Right now just remove it from prio tree | |
1513 | * as it is empty. | |
1514 | */ | |
1515 | if (cfqq->p_root) { | |
1516 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
1517 | cfqq->p_root = NULL; | |
1518 | } | |
1519 | } | |
1da177e4 LT |
1520 | } |
1521 | ||
5e705374 | 1522 | static void cfq_add_rq_rb(struct request *rq) |
1da177e4 | 1523 | { |
5e705374 | 1524 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
1da177e4 | 1525 | struct cfq_data *cfqd = cfqq->cfqd; |
796d5116 | 1526 | struct request *prev; |
1da177e4 | 1527 | |
5380a101 | 1528 | cfqq->queued[rq_is_sync(rq)]++; |
1da177e4 | 1529 | |
796d5116 | 1530 | elv_rb_add(&cfqq->sort_list, rq); |
5fccbf61 JA |
1531 | |
1532 | if (!cfq_cfqq_on_rr(cfqq)) | |
1533 | cfq_add_cfqq_rr(cfqd, cfqq); | |
5044eed4 JA |
1534 | |
1535 | /* | |
1536 | * check if this request is a better next-serve candidate | |
1537 | */ | |
a36e71f9 | 1538 | prev = cfqq->next_rq; |
cf7c25cf | 1539 | cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq, cfqd->last_position); |
a36e71f9 JA |
1540 | |
1541 | /* | |
1542 | * adjust priority tree position, if ->next_rq changes | |
1543 | */ | |
1544 | if (prev != cfqq->next_rq) | |
1545 | cfq_prio_tree_add(cfqd, cfqq); | |
1546 | ||
5044eed4 | 1547 | BUG_ON(!cfqq->next_rq); |
1da177e4 LT |
1548 | } |
1549 | ||
febffd61 | 1550 | static void cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq) |
1da177e4 | 1551 | { |
5380a101 JA |
1552 | elv_rb_del(&cfqq->sort_list, rq); |
1553 | cfqq->queued[rq_is_sync(rq)]--; | |
e98ef89b VG |
1554 | cfq_blkiocg_update_io_remove_stats(&(RQ_CFQG(rq))->blkg, |
1555 | rq_data_dir(rq), rq_is_sync(rq)); | |
5e705374 | 1556 | cfq_add_rq_rb(rq); |
e98ef89b | 1557 | cfq_blkiocg_update_io_add_stats(&(RQ_CFQG(rq))->blkg, |
7f1dc8a2 VG |
1558 | &cfqq->cfqd->serving_group->blkg, rq_data_dir(rq), |
1559 | rq_is_sync(rq)); | |
1da177e4 LT |
1560 | } |
1561 | ||
206dc69b JA |
1562 | static struct request * |
1563 | cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio) | |
1da177e4 | 1564 | { |
206dc69b | 1565 | struct task_struct *tsk = current; |
c5869807 | 1566 | struct cfq_io_cq *cic; |
206dc69b | 1567 | struct cfq_queue *cfqq; |
1da177e4 | 1568 | |
4ac845a2 | 1569 | cic = cfq_cic_lookup(cfqd, tsk->io_context); |
91fac317 VT |
1570 | if (!cic) |
1571 | return NULL; | |
1572 | ||
1573 | cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); | |
89850f7e JA |
1574 | if (cfqq) { |
1575 | sector_t sector = bio->bi_sector + bio_sectors(bio); | |
1576 | ||
21183b07 | 1577 | return elv_rb_find(&cfqq->sort_list, sector); |
89850f7e | 1578 | } |
1da177e4 | 1579 | |
1da177e4 LT |
1580 | return NULL; |
1581 | } | |
1582 | ||
165125e1 | 1583 | static void cfq_activate_request(struct request_queue *q, struct request *rq) |
1da177e4 | 1584 | { |
22e2c507 | 1585 | struct cfq_data *cfqd = q->elevator->elevator_data; |
3b18152c | 1586 | |
53c583d2 | 1587 | cfqd->rq_in_driver++; |
7b679138 | 1588 | cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "activate rq, drv=%d", |
53c583d2 | 1589 | cfqd->rq_in_driver); |
25776e35 | 1590 | |
5b93629b | 1591 | cfqd->last_position = blk_rq_pos(rq) + blk_rq_sectors(rq); |
1da177e4 LT |
1592 | } |
1593 | ||
165125e1 | 1594 | static void cfq_deactivate_request(struct request_queue *q, struct request *rq) |
1da177e4 | 1595 | { |
b4878f24 JA |
1596 | struct cfq_data *cfqd = q->elevator->elevator_data; |
1597 | ||
53c583d2 CZ |
1598 | WARN_ON(!cfqd->rq_in_driver); |
1599 | cfqd->rq_in_driver--; | |
7b679138 | 1600 | cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "deactivate rq, drv=%d", |
53c583d2 | 1601 | cfqd->rq_in_driver); |
1da177e4 LT |
1602 | } |
1603 | ||
b4878f24 | 1604 | static void cfq_remove_request(struct request *rq) |
1da177e4 | 1605 | { |
5e705374 | 1606 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
21183b07 | 1607 | |
5e705374 JA |
1608 | if (cfqq->next_rq == rq) |
1609 | cfqq->next_rq = cfq_find_next_rq(cfqq->cfqd, cfqq, rq); | |
1da177e4 | 1610 | |
b4878f24 | 1611 | list_del_init(&rq->queuelist); |
5e705374 | 1612 | cfq_del_rq_rb(rq); |
374f84ac | 1613 | |
45333d5a | 1614 | cfqq->cfqd->rq_queued--; |
e98ef89b VG |
1615 | cfq_blkiocg_update_io_remove_stats(&(RQ_CFQG(rq))->blkg, |
1616 | rq_data_dir(rq), rq_is_sync(rq)); | |
65299a3b CH |
1617 | if (rq->cmd_flags & REQ_PRIO) { |
1618 | WARN_ON(!cfqq->prio_pending); | |
1619 | cfqq->prio_pending--; | |
b53d1ed7 | 1620 | } |
1da177e4 LT |
1621 | } |
1622 | ||
165125e1 JA |
1623 | static int cfq_merge(struct request_queue *q, struct request **req, |
1624 | struct bio *bio) | |
1da177e4 LT |
1625 | { |
1626 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1627 | struct request *__rq; | |
1da177e4 | 1628 | |
206dc69b | 1629 | __rq = cfq_find_rq_fmerge(cfqd, bio); |
22e2c507 | 1630 | if (__rq && elv_rq_merge_ok(__rq, bio)) { |
9817064b JA |
1631 | *req = __rq; |
1632 | return ELEVATOR_FRONT_MERGE; | |
1da177e4 LT |
1633 | } |
1634 | ||
1635 | return ELEVATOR_NO_MERGE; | |
1da177e4 LT |
1636 | } |
1637 | ||
165125e1 | 1638 | static void cfq_merged_request(struct request_queue *q, struct request *req, |
21183b07 | 1639 | int type) |
1da177e4 | 1640 | { |
21183b07 | 1641 | if (type == ELEVATOR_FRONT_MERGE) { |
5e705374 | 1642 | struct cfq_queue *cfqq = RQ_CFQQ(req); |
1da177e4 | 1643 | |
5e705374 | 1644 | cfq_reposition_rq_rb(cfqq, req); |
1da177e4 | 1645 | } |
1da177e4 LT |
1646 | } |
1647 | ||
812d4026 DS |
1648 | static void cfq_bio_merged(struct request_queue *q, struct request *req, |
1649 | struct bio *bio) | |
1650 | { | |
e98ef89b VG |
1651 | cfq_blkiocg_update_io_merged_stats(&(RQ_CFQG(req))->blkg, |
1652 | bio_data_dir(bio), cfq_bio_sync(bio)); | |
812d4026 DS |
1653 | } |
1654 | ||
1da177e4 | 1655 | static void |
165125e1 | 1656 | cfq_merged_requests(struct request_queue *q, struct request *rq, |
1da177e4 LT |
1657 | struct request *next) |
1658 | { | |
cf7c25cf | 1659 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
4a0b75c7 SL |
1660 | struct cfq_data *cfqd = q->elevator->elevator_data; |
1661 | ||
22e2c507 JA |
1662 | /* |
1663 | * reposition in fifo if next is older than rq | |
1664 | */ | |
1665 | if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && | |
30996f40 | 1666 | time_before(rq_fifo_time(next), rq_fifo_time(rq))) { |
22e2c507 | 1667 | list_move(&rq->queuelist, &next->queuelist); |
30996f40 JA |
1668 | rq_set_fifo_time(rq, rq_fifo_time(next)); |
1669 | } | |
22e2c507 | 1670 | |
cf7c25cf CZ |
1671 | if (cfqq->next_rq == next) |
1672 | cfqq->next_rq = rq; | |
b4878f24 | 1673 | cfq_remove_request(next); |
e98ef89b VG |
1674 | cfq_blkiocg_update_io_merged_stats(&(RQ_CFQG(rq))->blkg, |
1675 | rq_data_dir(next), rq_is_sync(next)); | |
4a0b75c7 SL |
1676 | |
1677 | cfqq = RQ_CFQQ(next); | |
1678 | /* | |
1679 | * all requests of this queue are merged to other queues, delete it | |
1680 | * from the service tree. If it's the active_queue, | |
1681 | * cfq_dispatch_requests() will choose to expire it or do idle | |
1682 | */ | |
1683 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list) && | |
1684 | cfqq != cfqd->active_queue) | |
1685 | cfq_del_cfqq_rr(cfqd, cfqq); | |
22e2c507 JA |
1686 | } |
1687 | ||
165125e1 | 1688 | static int cfq_allow_merge(struct request_queue *q, struct request *rq, |
da775265 JA |
1689 | struct bio *bio) |
1690 | { | |
1691 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
c5869807 | 1692 | struct cfq_io_cq *cic; |
da775265 | 1693 | struct cfq_queue *cfqq; |
da775265 JA |
1694 | |
1695 | /* | |
ec8acb69 | 1696 | * Disallow merge of a sync bio into an async request. |
da775265 | 1697 | */ |
91fac317 | 1698 | if (cfq_bio_sync(bio) && !rq_is_sync(rq)) |
a6151c3a | 1699 | return false; |
da775265 JA |
1700 | |
1701 | /* | |
f1a4f4d3 | 1702 | * Lookup the cfqq that this bio will be queued with and allow |
07c2bd37 | 1703 | * merge only if rq is queued there. |
f1a4f4d3 | 1704 | */ |
07c2bd37 TH |
1705 | cic = cfq_cic_lookup(cfqd, current->io_context); |
1706 | if (!cic) | |
1707 | return false; | |
719d3402 | 1708 | |
91fac317 | 1709 | cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); |
a6151c3a | 1710 | return cfqq == RQ_CFQQ(rq); |
da775265 JA |
1711 | } |
1712 | ||
812df48d DS |
1713 | static inline void cfq_del_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1714 | { | |
1715 | del_timer(&cfqd->idle_slice_timer); | |
e98ef89b | 1716 | cfq_blkiocg_update_idle_time_stats(&cfqq->cfqg->blkg); |
812df48d DS |
1717 | } |
1718 | ||
febffd61 JA |
1719 | static void __cfq_set_active_queue(struct cfq_data *cfqd, |
1720 | struct cfq_queue *cfqq) | |
22e2c507 JA |
1721 | { |
1722 | if (cfqq) { | |
b1ffe737 DS |
1723 | cfq_log_cfqq(cfqd, cfqq, "set_active wl_prio:%d wl_type:%d", |
1724 | cfqd->serving_prio, cfqd->serving_type); | |
62a37f6b JT |
1725 | cfq_blkiocg_update_avg_queue_size_stats(&cfqq->cfqg->blkg); |
1726 | cfqq->slice_start = 0; | |
1727 | cfqq->dispatch_start = jiffies; | |
1728 | cfqq->allocated_slice = 0; | |
1729 | cfqq->slice_end = 0; | |
1730 | cfqq->slice_dispatch = 0; | |
1731 | cfqq->nr_sectors = 0; | |
1732 | ||
1733 | cfq_clear_cfqq_wait_request(cfqq); | |
1734 | cfq_clear_cfqq_must_dispatch(cfqq); | |
1735 | cfq_clear_cfqq_must_alloc_slice(cfqq); | |
1736 | cfq_clear_cfqq_fifo_expire(cfqq); | |
1737 | cfq_mark_cfqq_slice_new(cfqq); | |
1738 | ||
1739 | cfq_del_timer(cfqd, cfqq); | |
22e2c507 JA |
1740 | } |
1741 | ||
1742 | cfqd->active_queue = cfqq; | |
1743 | } | |
1744 | ||
7b14e3b5 JA |
1745 | /* |
1746 | * current cfqq expired its slice (or was too idle), select new one | |
1747 | */ | |
1748 | static void | |
1749 | __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
e5ff082e | 1750 | bool timed_out) |
7b14e3b5 | 1751 | { |
7b679138 JA |
1752 | cfq_log_cfqq(cfqd, cfqq, "slice expired t=%d", timed_out); |
1753 | ||
7b14e3b5 | 1754 | if (cfq_cfqq_wait_request(cfqq)) |
812df48d | 1755 | cfq_del_timer(cfqd, cfqq); |
7b14e3b5 | 1756 | |
7b14e3b5 | 1757 | cfq_clear_cfqq_wait_request(cfqq); |
f75edf2d | 1758 | cfq_clear_cfqq_wait_busy(cfqq); |
7b14e3b5 | 1759 | |
ae54abed SL |
1760 | /* |
1761 | * If this cfqq is shared between multiple processes, check to | |
1762 | * make sure that those processes are still issuing I/Os within | |
1763 | * the mean seek distance. If not, it may be time to break the | |
1764 | * queues apart again. | |
1765 | */ | |
1766 | if (cfq_cfqq_coop(cfqq) && CFQQ_SEEKY(cfqq)) | |
1767 | cfq_mark_cfqq_split_coop(cfqq); | |
1768 | ||
7b14e3b5 | 1769 | /* |
6084cdda | 1770 | * store what was left of this slice, if the queue idled/timed out |
7b14e3b5 | 1771 | */ |
c553f8e3 SL |
1772 | if (timed_out) { |
1773 | if (cfq_cfqq_slice_new(cfqq)) | |
ba5bd520 | 1774 | cfqq->slice_resid = cfq_scaled_cfqq_slice(cfqd, cfqq); |
c553f8e3 SL |
1775 | else |
1776 | cfqq->slice_resid = cfqq->slice_end - jiffies; | |
7b679138 JA |
1777 | cfq_log_cfqq(cfqd, cfqq, "resid=%ld", cfqq->slice_resid); |
1778 | } | |
7b14e3b5 | 1779 | |
e5ff082e | 1780 | cfq_group_served(cfqd, cfqq->cfqg, cfqq); |
dae739eb | 1781 | |
f04a6424 VG |
1782 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) |
1783 | cfq_del_cfqq_rr(cfqd, cfqq); | |
1784 | ||
edd75ffd | 1785 | cfq_resort_rr_list(cfqd, cfqq); |
7b14e3b5 JA |
1786 | |
1787 | if (cfqq == cfqd->active_queue) | |
1788 | cfqd->active_queue = NULL; | |
1789 | ||
1790 | if (cfqd->active_cic) { | |
11a3122f | 1791 | put_io_context(cfqd->active_cic->icq.ioc); |
7b14e3b5 JA |
1792 | cfqd->active_cic = NULL; |
1793 | } | |
7b14e3b5 JA |
1794 | } |
1795 | ||
e5ff082e | 1796 | static inline void cfq_slice_expired(struct cfq_data *cfqd, bool timed_out) |
7b14e3b5 JA |
1797 | { |
1798 | struct cfq_queue *cfqq = cfqd->active_queue; | |
1799 | ||
1800 | if (cfqq) | |
e5ff082e | 1801 | __cfq_slice_expired(cfqd, cfqq, timed_out); |
7b14e3b5 JA |
1802 | } |
1803 | ||
498d3aa2 JA |
1804 | /* |
1805 | * Get next queue for service. Unless we have a queue preemption, | |
1806 | * we'll simply select the first cfqq in the service tree. | |
1807 | */ | |
6d048f53 | 1808 | static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd) |
22e2c507 | 1809 | { |
c0324a02 | 1810 | struct cfq_rb_root *service_tree = |
cdb16e8f | 1811 | service_tree_for(cfqd->serving_group, cfqd->serving_prio, |
65b32a57 | 1812 | cfqd->serving_type); |
d9e7620e | 1813 | |
f04a6424 VG |
1814 | if (!cfqd->rq_queued) |
1815 | return NULL; | |
1816 | ||
1fa8f6d6 VG |
1817 | /* There is nothing to dispatch */ |
1818 | if (!service_tree) | |
1819 | return NULL; | |
c0324a02 CZ |
1820 | if (RB_EMPTY_ROOT(&service_tree->rb)) |
1821 | return NULL; | |
1822 | return cfq_rb_first(service_tree); | |
6d048f53 JA |
1823 | } |
1824 | ||
f04a6424 VG |
1825 | static struct cfq_queue *cfq_get_next_queue_forced(struct cfq_data *cfqd) |
1826 | { | |
25fb5169 | 1827 | struct cfq_group *cfqg; |
f04a6424 VG |
1828 | struct cfq_queue *cfqq; |
1829 | int i, j; | |
1830 | struct cfq_rb_root *st; | |
1831 | ||
1832 | if (!cfqd->rq_queued) | |
1833 | return NULL; | |
1834 | ||
25fb5169 VG |
1835 | cfqg = cfq_get_next_cfqg(cfqd); |
1836 | if (!cfqg) | |
1837 | return NULL; | |
1838 | ||
f04a6424 VG |
1839 | for_each_cfqg_st(cfqg, i, j, st) |
1840 | if ((cfqq = cfq_rb_first(st)) != NULL) | |
1841 | return cfqq; | |
1842 | return NULL; | |
1843 | } | |
1844 | ||
498d3aa2 JA |
1845 | /* |
1846 | * Get and set a new active queue for service. | |
1847 | */ | |
a36e71f9 JA |
1848 | static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd, |
1849 | struct cfq_queue *cfqq) | |
6d048f53 | 1850 | { |
e00ef799 | 1851 | if (!cfqq) |
a36e71f9 | 1852 | cfqq = cfq_get_next_queue(cfqd); |
6d048f53 | 1853 | |
22e2c507 | 1854 | __cfq_set_active_queue(cfqd, cfqq); |
3b18152c | 1855 | return cfqq; |
22e2c507 JA |
1856 | } |
1857 | ||
d9e7620e JA |
1858 | static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd, |
1859 | struct request *rq) | |
1860 | { | |
83096ebf TH |
1861 | if (blk_rq_pos(rq) >= cfqd->last_position) |
1862 | return blk_rq_pos(rq) - cfqd->last_position; | |
d9e7620e | 1863 | else |
83096ebf | 1864 | return cfqd->last_position - blk_rq_pos(rq); |
d9e7620e JA |
1865 | } |
1866 | ||
b2c18e1e | 1867 | static inline int cfq_rq_close(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
e9ce335d | 1868 | struct request *rq) |
6d048f53 | 1869 | { |
e9ce335d | 1870 | return cfq_dist_from_last(cfqd, rq) <= CFQQ_CLOSE_THR; |
6d048f53 JA |
1871 | } |
1872 | ||
a36e71f9 JA |
1873 | static struct cfq_queue *cfqq_close(struct cfq_data *cfqd, |
1874 | struct cfq_queue *cur_cfqq) | |
1875 | { | |
f2d1f0ae | 1876 | struct rb_root *root = &cfqd->prio_trees[cur_cfqq->org_ioprio]; |
a36e71f9 JA |
1877 | struct rb_node *parent, *node; |
1878 | struct cfq_queue *__cfqq; | |
1879 | sector_t sector = cfqd->last_position; | |
1880 | ||
1881 | if (RB_EMPTY_ROOT(root)) | |
1882 | return NULL; | |
1883 | ||
1884 | /* | |
1885 | * First, if we find a request starting at the end of the last | |
1886 | * request, choose it. | |
1887 | */ | |
f2d1f0ae | 1888 | __cfqq = cfq_prio_tree_lookup(cfqd, root, sector, &parent, NULL); |
a36e71f9 JA |
1889 | if (__cfqq) |
1890 | return __cfqq; | |
1891 | ||
1892 | /* | |
1893 | * If the exact sector wasn't found, the parent of the NULL leaf | |
1894 | * will contain the closest sector. | |
1895 | */ | |
1896 | __cfqq = rb_entry(parent, struct cfq_queue, p_node); | |
e9ce335d | 1897 | if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq)) |
a36e71f9 JA |
1898 | return __cfqq; |
1899 | ||
2e46e8b2 | 1900 | if (blk_rq_pos(__cfqq->next_rq) < sector) |
a36e71f9 JA |
1901 | node = rb_next(&__cfqq->p_node); |
1902 | else | |
1903 | node = rb_prev(&__cfqq->p_node); | |
1904 | if (!node) | |
1905 | return NULL; | |
1906 | ||
1907 | __cfqq = rb_entry(node, struct cfq_queue, p_node); | |
e9ce335d | 1908 | if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq)) |
a36e71f9 JA |
1909 | return __cfqq; |
1910 | ||
1911 | return NULL; | |
1912 | } | |
1913 | ||
1914 | /* | |
1915 | * cfqd - obvious | |
1916 | * cur_cfqq - passed in so that we don't decide that the current queue is | |
1917 | * closely cooperating with itself. | |
1918 | * | |
1919 | * So, basically we're assuming that that cur_cfqq has dispatched at least | |
1920 | * one request, and that cfqd->last_position reflects a position on the disk | |
1921 | * associated with the I/O issued by cur_cfqq. I'm not sure this is a valid | |
1922 | * assumption. | |
1923 | */ | |
1924 | static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd, | |
b3b6d040 | 1925 | struct cfq_queue *cur_cfqq) |
6d048f53 | 1926 | { |
a36e71f9 JA |
1927 | struct cfq_queue *cfqq; |
1928 | ||
39c01b21 DS |
1929 | if (cfq_class_idle(cur_cfqq)) |
1930 | return NULL; | |
e6c5bc73 JM |
1931 | if (!cfq_cfqq_sync(cur_cfqq)) |
1932 | return NULL; | |
1933 | if (CFQQ_SEEKY(cur_cfqq)) | |
1934 | return NULL; | |
1935 | ||
b9d8f4c7 GJ |
1936 | /* |
1937 | * Don't search priority tree if it's the only queue in the group. | |
1938 | */ | |
1939 | if (cur_cfqq->cfqg->nr_cfqq == 1) | |
1940 | return NULL; | |
1941 | ||
6d048f53 | 1942 | /* |
d9e7620e JA |
1943 | * We should notice if some of the queues are cooperating, eg |
1944 | * working closely on the same area of the disk. In that case, | |
1945 | * we can group them together and don't waste time idling. | |
6d048f53 | 1946 | */ |
a36e71f9 JA |
1947 | cfqq = cfqq_close(cfqd, cur_cfqq); |
1948 | if (!cfqq) | |
1949 | return NULL; | |
1950 | ||
8682e1f1 VG |
1951 | /* If new queue belongs to different cfq_group, don't choose it */ |
1952 | if (cur_cfqq->cfqg != cfqq->cfqg) | |
1953 | return NULL; | |
1954 | ||
df5fe3e8 JM |
1955 | /* |
1956 | * It only makes sense to merge sync queues. | |
1957 | */ | |
1958 | if (!cfq_cfqq_sync(cfqq)) | |
1959 | return NULL; | |
e6c5bc73 JM |
1960 | if (CFQQ_SEEKY(cfqq)) |
1961 | return NULL; | |
df5fe3e8 | 1962 | |
c0324a02 CZ |
1963 | /* |
1964 | * Do not merge queues of different priority classes | |
1965 | */ | |
1966 | if (cfq_class_rt(cfqq) != cfq_class_rt(cur_cfqq)) | |
1967 | return NULL; | |
1968 | ||
a36e71f9 | 1969 | return cfqq; |
6d048f53 JA |
1970 | } |
1971 | ||
a6d44e98 CZ |
1972 | /* |
1973 | * Determine whether we should enforce idle window for this queue. | |
1974 | */ | |
1975 | ||
1976 | static bool cfq_should_idle(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1977 | { | |
1978 | enum wl_prio_t prio = cfqq_prio(cfqq); | |
718eee05 | 1979 | struct cfq_rb_root *service_tree = cfqq->service_tree; |
a6d44e98 | 1980 | |
f04a6424 VG |
1981 | BUG_ON(!service_tree); |
1982 | BUG_ON(!service_tree->count); | |
1983 | ||
b6508c16 VG |
1984 | if (!cfqd->cfq_slice_idle) |
1985 | return false; | |
1986 | ||
a6d44e98 CZ |
1987 | /* We never do for idle class queues. */ |
1988 | if (prio == IDLE_WORKLOAD) | |
1989 | return false; | |
1990 | ||
1991 | /* We do for queues that were marked with idle window flag. */ | |
3c764b7a SL |
1992 | if (cfq_cfqq_idle_window(cfqq) && |
1993 | !(blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag)) | |
a6d44e98 CZ |
1994 | return true; |
1995 | ||
1996 | /* | |
1997 | * Otherwise, we do only if they are the last ones | |
1998 | * in their service tree. | |
1999 | */ | |
f5f2b6ce SL |
2000 | if (service_tree->count == 1 && cfq_cfqq_sync(cfqq) && |
2001 | !cfq_io_thinktime_big(cfqd, &service_tree->ttime, false)) | |
c1e44756 | 2002 | return true; |
b1ffe737 DS |
2003 | cfq_log_cfqq(cfqd, cfqq, "Not idling. st->count:%d", |
2004 | service_tree->count); | |
c1e44756 | 2005 | return false; |
a6d44e98 CZ |
2006 | } |
2007 | ||
6d048f53 | 2008 | static void cfq_arm_slice_timer(struct cfq_data *cfqd) |
22e2c507 | 2009 | { |
1792669c | 2010 | struct cfq_queue *cfqq = cfqd->active_queue; |
c5869807 | 2011 | struct cfq_io_cq *cic; |
80bdf0c7 | 2012 | unsigned long sl, group_idle = 0; |
7b14e3b5 | 2013 | |
a68bbddb | 2014 | /* |
f7d7b7a7 JA |
2015 | * SSD device without seek penalty, disable idling. But only do so |
2016 | * for devices that support queuing, otherwise we still have a problem | |
2017 | * with sync vs async workloads. | |
a68bbddb | 2018 | */ |
f7d7b7a7 | 2019 | if (blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag) |
a68bbddb JA |
2020 | return; |
2021 | ||
dd67d051 | 2022 | WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list)); |
6d048f53 | 2023 | WARN_ON(cfq_cfqq_slice_new(cfqq)); |
22e2c507 JA |
2024 | |
2025 | /* | |
2026 | * idle is disabled, either manually or by past process history | |
2027 | */ | |
80bdf0c7 VG |
2028 | if (!cfq_should_idle(cfqd, cfqq)) { |
2029 | /* no queue idling. Check for group idling */ | |
2030 | if (cfqd->cfq_group_idle) | |
2031 | group_idle = cfqd->cfq_group_idle; | |
2032 | else | |
2033 | return; | |
2034 | } | |
6d048f53 | 2035 | |
7b679138 | 2036 | /* |
8e550632 | 2037 | * still active requests from this queue, don't idle |
7b679138 | 2038 | */ |
8e550632 | 2039 | if (cfqq->dispatched) |
7b679138 JA |
2040 | return; |
2041 | ||
22e2c507 JA |
2042 | /* |
2043 | * task has exited, don't wait | |
2044 | */ | |
206dc69b | 2045 | cic = cfqd->active_cic; |
c5869807 | 2046 | if (!cic || !atomic_read(&cic->icq.ioc->nr_tasks)) |
6d048f53 JA |
2047 | return; |
2048 | ||
355b659c CZ |
2049 | /* |
2050 | * If our average think time is larger than the remaining time | |
2051 | * slice, then don't idle. This avoids overrunning the allotted | |
2052 | * time slice. | |
2053 | */ | |
383cd721 SL |
2054 | if (sample_valid(cic->ttime.ttime_samples) && |
2055 | (cfqq->slice_end - jiffies < cic->ttime.ttime_mean)) { | |
fd16d263 | 2056 | cfq_log_cfqq(cfqd, cfqq, "Not idling. think_time:%lu", |
383cd721 | 2057 | cic->ttime.ttime_mean); |
355b659c | 2058 | return; |
b1ffe737 | 2059 | } |
355b659c | 2060 | |
80bdf0c7 VG |
2061 | /* There are other queues in the group, don't do group idle */ |
2062 | if (group_idle && cfqq->cfqg->nr_cfqq > 1) | |
2063 | return; | |
2064 | ||
3b18152c | 2065 | cfq_mark_cfqq_wait_request(cfqq); |
22e2c507 | 2066 | |
80bdf0c7 VG |
2067 | if (group_idle) |
2068 | sl = cfqd->cfq_group_idle; | |
2069 | else | |
2070 | sl = cfqd->cfq_slice_idle; | |
206dc69b | 2071 | |
7b14e3b5 | 2072 | mod_timer(&cfqd->idle_slice_timer, jiffies + sl); |
e98ef89b | 2073 | cfq_blkiocg_update_set_idle_time_stats(&cfqq->cfqg->blkg); |
80bdf0c7 VG |
2074 | cfq_log_cfqq(cfqd, cfqq, "arm_idle: %lu group_idle: %d", sl, |
2075 | group_idle ? 1 : 0); | |
1da177e4 LT |
2076 | } |
2077 | ||
498d3aa2 JA |
2078 | /* |
2079 | * Move request from internal lists to the request queue dispatch list. | |
2080 | */ | |
165125e1 | 2081 | static void cfq_dispatch_insert(struct request_queue *q, struct request *rq) |
1da177e4 | 2082 | { |
3ed9a296 | 2083 | struct cfq_data *cfqd = q->elevator->elevator_data; |
5e705374 | 2084 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 | 2085 | |
7b679138 JA |
2086 | cfq_log_cfqq(cfqd, cfqq, "dispatch_insert"); |
2087 | ||
06d21886 | 2088 | cfqq->next_rq = cfq_find_next_rq(cfqd, cfqq, rq); |
5380a101 | 2089 | cfq_remove_request(rq); |
6d048f53 | 2090 | cfqq->dispatched++; |
80bdf0c7 | 2091 | (RQ_CFQG(rq))->dispatched++; |
5380a101 | 2092 | elv_dispatch_sort(q, rq); |
3ed9a296 | 2093 | |
53c583d2 | 2094 | cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]++; |
c4e7893e | 2095 | cfqq->nr_sectors += blk_rq_sectors(rq); |
e98ef89b | 2096 | cfq_blkiocg_update_dispatch_stats(&cfqq->cfqg->blkg, blk_rq_bytes(rq), |
84c124da | 2097 | rq_data_dir(rq), rq_is_sync(rq)); |
1da177e4 LT |
2098 | } |
2099 | ||
2100 | /* | |
2101 | * return expired entry, or NULL to just start from scratch in rbtree | |
2102 | */ | |
febffd61 | 2103 | static struct request *cfq_check_fifo(struct cfq_queue *cfqq) |
1da177e4 | 2104 | { |
30996f40 | 2105 | struct request *rq = NULL; |
1da177e4 | 2106 | |
3b18152c | 2107 | if (cfq_cfqq_fifo_expire(cfqq)) |
1da177e4 | 2108 | return NULL; |
cb887411 JA |
2109 | |
2110 | cfq_mark_cfqq_fifo_expire(cfqq); | |
2111 | ||
89850f7e JA |
2112 | if (list_empty(&cfqq->fifo)) |
2113 | return NULL; | |
1da177e4 | 2114 | |
89850f7e | 2115 | rq = rq_entry_fifo(cfqq->fifo.next); |
30996f40 | 2116 | if (time_before(jiffies, rq_fifo_time(rq))) |
7b679138 | 2117 | rq = NULL; |
1da177e4 | 2118 | |
30996f40 | 2119 | cfq_log_cfqq(cfqq->cfqd, cfqq, "fifo=%p", rq); |
6d048f53 | 2120 | return rq; |
1da177e4 LT |
2121 | } |
2122 | ||
22e2c507 JA |
2123 | static inline int |
2124 | cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
2125 | { | |
2126 | const int base_rq = cfqd->cfq_slice_async_rq; | |
1da177e4 | 2127 | |
22e2c507 | 2128 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); |
1da177e4 | 2129 | |
b9f8ce05 | 2130 | return 2 * base_rq * (IOPRIO_BE_NR - cfqq->ioprio); |
1da177e4 LT |
2131 | } |
2132 | ||
df5fe3e8 JM |
2133 | /* |
2134 | * Must be called with the queue_lock held. | |
2135 | */ | |
2136 | static int cfqq_process_refs(struct cfq_queue *cfqq) | |
2137 | { | |
2138 | int process_refs, io_refs; | |
2139 | ||
2140 | io_refs = cfqq->allocated[READ] + cfqq->allocated[WRITE]; | |
30d7b944 | 2141 | process_refs = cfqq->ref - io_refs; |
df5fe3e8 JM |
2142 | BUG_ON(process_refs < 0); |
2143 | return process_refs; | |
2144 | } | |
2145 | ||
2146 | static void cfq_setup_merge(struct cfq_queue *cfqq, struct cfq_queue *new_cfqq) | |
2147 | { | |
e6c5bc73 | 2148 | int process_refs, new_process_refs; |
df5fe3e8 JM |
2149 | struct cfq_queue *__cfqq; |
2150 | ||
c10b61f0 JM |
2151 | /* |
2152 | * If there are no process references on the new_cfqq, then it is | |
2153 | * unsafe to follow the ->new_cfqq chain as other cfqq's in the | |
2154 | * chain may have dropped their last reference (not just their | |
2155 | * last process reference). | |
2156 | */ | |
2157 | if (!cfqq_process_refs(new_cfqq)) | |
2158 | return; | |
2159 | ||
df5fe3e8 JM |
2160 | /* Avoid a circular list and skip interim queue merges */ |
2161 | while ((__cfqq = new_cfqq->new_cfqq)) { | |
2162 | if (__cfqq == cfqq) | |
2163 | return; | |
2164 | new_cfqq = __cfqq; | |
2165 | } | |
2166 | ||
2167 | process_refs = cfqq_process_refs(cfqq); | |
c10b61f0 | 2168 | new_process_refs = cfqq_process_refs(new_cfqq); |
df5fe3e8 JM |
2169 | /* |
2170 | * If the process for the cfqq has gone away, there is no | |
2171 | * sense in merging the queues. | |
2172 | */ | |
c10b61f0 | 2173 | if (process_refs == 0 || new_process_refs == 0) |
df5fe3e8 JM |
2174 | return; |
2175 | ||
e6c5bc73 JM |
2176 | /* |
2177 | * Merge in the direction of the lesser amount of work. | |
2178 | */ | |
e6c5bc73 JM |
2179 | if (new_process_refs >= process_refs) { |
2180 | cfqq->new_cfqq = new_cfqq; | |
30d7b944 | 2181 | new_cfqq->ref += process_refs; |
e6c5bc73 JM |
2182 | } else { |
2183 | new_cfqq->new_cfqq = cfqq; | |
30d7b944 | 2184 | cfqq->ref += new_process_refs; |
e6c5bc73 | 2185 | } |
df5fe3e8 JM |
2186 | } |
2187 | ||
cdb16e8f | 2188 | static enum wl_type_t cfq_choose_wl(struct cfq_data *cfqd, |
65b32a57 | 2189 | struct cfq_group *cfqg, enum wl_prio_t prio) |
718eee05 CZ |
2190 | { |
2191 | struct cfq_queue *queue; | |
2192 | int i; | |
2193 | bool key_valid = false; | |
2194 | unsigned long lowest_key = 0; | |
2195 | enum wl_type_t cur_best = SYNC_NOIDLE_WORKLOAD; | |
2196 | ||
65b32a57 VG |
2197 | for (i = 0; i <= SYNC_WORKLOAD; ++i) { |
2198 | /* select the one with lowest rb_key */ | |
2199 | queue = cfq_rb_first(service_tree_for(cfqg, prio, i)); | |
718eee05 CZ |
2200 | if (queue && |
2201 | (!key_valid || time_before(queue->rb_key, lowest_key))) { | |
2202 | lowest_key = queue->rb_key; | |
2203 | cur_best = i; | |
2204 | key_valid = true; | |
2205 | } | |
2206 | } | |
2207 | ||
2208 | return cur_best; | |
2209 | } | |
2210 | ||
cdb16e8f | 2211 | static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg) |
718eee05 | 2212 | { |
718eee05 CZ |
2213 | unsigned slice; |
2214 | unsigned count; | |
cdb16e8f | 2215 | struct cfq_rb_root *st; |
58ff82f3 | 2216 | unsigned group_slice; |
e4ea0c16 | 2217 | enum wl_prio_t original_prio = cfqd->serving_prio; |
1fa8f6d6 | 2218 | |
718eee05 | 2219 | /* Choose next priority. RT > BE > IDLE */ |
58ff82f3 | 2220 | if (cfq_group_busy_queues_wl(RT_WORKLOAD, cfqd, cfqg)) |
718eee05 | 2221 | cfqd->serving_prio = RT_WORKLOAD; |
58ff82f3 | 2222 | else if (cfq_group_busy_queues_wl(BE_WORKLOAD, cfqd, cfqg)) |
718eee05 CZ |
2223 | cfqd->serving_prio = BE_WORKLOAD; |
2224 | else { | |
2225 | cfqd->serving_prio = IDLE_WORKLOAD; | |
2226 | cfqd->workload_expires = jiffies + 1; | |
2227 | return; | |
2228 | } | |
2229 | ||
e4ea0c16 SL |
2230 | if (original_prio != cfqd->serving_prio) |
2231 | goto new_workload; | |
2232 | ||
718eee05 CZ |
2233 | /* |
2234 | * For RT and BE, we have to choose also the type | |
2235 | * (SYNC, SYNC_NOIDLE, ASYNC), and to compute a workload | |
2236 | * expiration time | |
2237 | */ | |
65b32a57 | 2238 | st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type); |
cdb16e8f | 2239 | count = st->count; |
718eee05 CZ |
2240 | |
2241 | /* | |
65b32a57 | 2242 | * check workload expiration, and that we still have other queues ready |
718eee05 | 2243 | */ |
65b32a57 | 2244 | if (count && !time_after(jiffies, cfqd->workload_expires)) |
718eee05 CZ |
2245 | return; |
2246 | ||
e4ea0c16 | 2247 | new_workload: |
718eee05 CZ |
2248 | /* otherwise select new workload type */ |
2249 | cfqd->serving_type = | |
65b32a57 VG |
2250 | cfq_choose_wl(cfqd, cfqg, cfqd->serving_prio); |
2251 | st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type); | |
cdb16e8f | 2252 | count = st->count; |
718eee05 CZ |
2253 | |
2254 | /* | |
2255 | * the workload slice is computed as a fraction of target latency | |
2256 | * proportional to the number of queues in that workload, over | |
2257 | * all the queues in the same priority class | |
2258 | */ | |
58ff82f3 VG |
2259 | group_slice = cfq_group_slice(cfqd, cfqg); |
2260 | ||
2261 | slice = group_slice * count / | |
2262 | max_t(unsigned, cfqg->busy_queues_avg[cfqd->serving_prio], | |
2263 | cfq_group_busy_queues_wl(cfqd->serving_prio, cfqd, cfqg)); | |
718eee05 | 2264 | |
f26bd1f0 VG |
2265 | if (cfqd->serving_type == ASYNC_WORKLOAD) { |
2266 | unsigned int tmp; | |
2267 | ||
2268 | /* | |
2269 | * Async queues are currently system wide. Just taking | |
2270 | * proportion of queues with-in same group will lead to higher | |
2271 | * async ratio system wide as generally root group is going | |
2272 | * to have higher weight. A more accurate thing would be to | |
2273 | * calculate system wide asnc/sync ratio. | |
2274 | */ | |
5bf14c07 TM |
2275 | tmp = cfqd->cfq_target_latency * |
2276 | cfqg_busy_async_queues(cfqd, cfqg); | |
f26bd1f0 VG |
2277 | tmp = tmp/cfqd->busy_queues; |
2278 | slice = min_t(unsigned, slice, tmp); | |
2279 | ||
718eee05 CZ |
2280 | /* async workload slice is scaled down according to |
2281 | * the sync/async slice ratio. */ | |
2282 | slice = slice * cfqd->cfq_slice[0] / cfqd->cfq_slice[1]; | |
f26bd1f0 | 2283 | } else |
718eee05 CZ |
2284 | /* sync workload slice is at least 2 * cfq_slice_idle */ |
2285 | slice = max(slice, 2 * cfqd->cfq_slice_idle); | |
2286 | ||
2287 | slice = max_t(unsigned, slice, CFQ_MIN_TT); | |
b1ffe737 | 2288 | cfq_log(cfqd, "workload slice:%d", slice); |
718eee05 CZ |
2289 | cfqd->workload_expires = jiffies + slice; |
2290 | } | |
2291 | ||
1fa8f6d6 VG |
2292 | static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd) |
2293 | { | |
2294 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
25bc6b07 | 2295 | struct cfq_group *cfqg; |
1fa8f6d6 VG |
2296 | |
2297 | if (RB_EMPTY_ROOT(&st->rb)) | |
2298 | return NULL; | |
25bc6b07 | 2299 | cfqg = cfq_rb_first_group(st); |
25bc6b07 VG |
2300 | update_min_vdisktime(st); |
2301 | return cfqg; | |
1fa8f6d6 VG |
2302 | } |
2303 | ||
cdb16e8f VG |
2304 | static void cfq_choose_cfqg(struct cfq_data *cfqd) |
2305 | { | |
1fa8f6d6 VG |
2306 | struct cfq_group *cfqg = cfq_get_next_cfqg(cfqd); |
2307 | ||
2308 | cfqd->serving_group = cfqg; | |
dae739eb VG |
2309 | |
2310 | /* Restore the workload type data */ | |
2311 | if (cfqg->saved_workload_slice) { | |
2312 | cfqd->workload_expires = jiffies + cfqg->saved_workload_slice; | |
2313 | cfqd->serving_type = cfqg->saved_workload; | |
2314 | cfqd->serving_prio = cfqg->saved_serving_prio; | |
66ae2919 GJ |
2315 | } else |
2316 | cfqd->workload_expires = jiffies - 1; | |
2317 | ||
1fa8f6d6 | 2318 | choose_service_tree(cfqd, cfqg); |
cdb16e8f VG |
2319 | } |
2320 | ||
22e2c507 | 2321 | /* |
498d3aa2 JA |
2322 | * Select a queue for service. If we have a current active queue, |
2323 | * check whether to continue servicing it, or retrieve and set a new one. | |
22e2c507 | 2324 | */ |
1b5ed5e1 | 2325 | static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) |
1da177e4 | 2326 | { |
a36e71f9 | 2327 | struct cfq_queue *cfqq, *new_cfqq = NULL; |
1da177e4 | 2328 | |
22e2c507 JA |
2329 | cfqq = cfqd->active_queue; |
2330 | if (!cfqq) | |
2331 | goto new_queue; | |
1da177e4 | 2332 | |
f04a6424 VG |
2333 | if (!cfqd->rq_queued) |
2334 | return NULL; | |
c244bb50 VG |
2335 | |
2336 | /* | |
2337 | * We were waiting for group to get backlogged. Expire the queue | |
2338 | */ | |
2339 | if (cfq_cfqq_wait_busy(cfqq) && !RB_EMPTY_ROOT(&cfqq->sort_list)) | |
2340 | goto expire; | |
2341 | ||
22e2c507 | 2342 | /* |
6d048f53 | 2343 | * The active queue has run out of time, expire it and select new. |
22e2c507 | 2344 | */ |
7667aa06 VG |
2345 | if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq)) { |
2346 | /* | |
2347 | * If slice had not expired at the completion of last request | |
2348 | * we might not have turned on wait_busy flag. Don't expire | |
2349 | * the queue yet. Allow the group to get backlogged. | |
2350 | * | |
2351 | * The very fact that we have used the slice, that means we | |
2352 | * have been idling all along on this queue and it should be | |
2353 | * ok to wait for this request to complete. | |
2354 | */ | |
82bbbf28 VG |
2355 | if (cfqq->cfqg->nr_cfqq == 1 && RB_EMPTY_ROOT(&cfqq->sort_list) |
2356 | && cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) { | |
2357 | cfqq = NULL; | |
7667aa06 | 2358 | goto keep_queue; |
82bbbf28 | 2359 | } else |
80bdf0c7 | 2360 | goto check_group_idle; |
7667aa06 | 2361 | } |
1da177e4 | 2362 | |
22e2c507 | 2363 | /* |
6d048f53 JA |
2364 | * The active queue has requests and isn't expired, allow it to |
2365 | * dispatch. | |
22e2c507 | 2366 | */ |
dd67d051 | 2367 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
22e2c507 | 2368 | goto keep_queue; |
6d048f53 | 2369 | |
a36e71f9 JA |
2370 | /* |
2371 | * If another queue has a request waiting within our mean seek | |
2372 | * distance, let it run. The expire code will check for close | |
2373 | * cooperators and put the close queue at the front of the service | |
df5fe3e8 | 2374 | * tree. If possible, merge the expiring queue with the new cfqq. |
a36e71f9 | 2375 | */ |
b3b6d040 | 2376 | new_cfqq = cfq_close_cooperator(cfqd, cfqq); |
df5fe3e8 JM |
2377 | if (new_cfqq) { |
2378 | if (!cfqq->new_cfqq) | |
2379 | cfq_setup_merge(cfqq, new_cfqq); | |
a36e71f9 | 2380 | goto expire; |
df5fe3e8 | 2381 | } |
a36e71f9 | 2382 | |
6d048f53 JA |
2383 | /* |
2384 | * No requests pending. If the active queue still has requests in | |
2385 | * flight or is idling for a new request, allow either of these | |
2386 | * conditions to happen (or time out) before selecting a new queue. | |
2387 | */ | |
80bdf0c7 VG |
2388 | if (timer_pending(&cfqd->idle_slice_timer)) { |
2389 | cfqq = NULL; | |
2390 | goto keep_queue; | |
2391 | } | |
2392 | ||
8e1ac665 SL |
2393 | /* |
2394 | * This is a deep seek queue, but the device is much faster than | |
2395 | * the queue can deliver, don't idle | |
2396 | **/ | |
2397 | if (CFQQ_SEEKY(cfqq) && cfq_cfqq_idle_window(cfqq) && | |
2398 | (cfq_cfqq_slice_new(cfqq) || | |
2399 | (cfqq->slice_end - jiffies > jiffies - cfqq->slice_start))) { | |
2400 | cfq_clear_cfqq_deep(cfqq); | |
2401 | cfq_clear_cfqq_idle_window(cfqq); | |
2402 | } | |
2403 | ||
80bdf0c7 VG |
2404 | if (cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) { |
2405 | cfqq = NULL; | |
2406 | goto keep_queue; | |
2407 | } | |
2408 | ||
2409 | /* | |
2410 | * If group idle is enabled and there are requests dispatched from | |
2411 | * this group, wait for requests to complete. | |
2412 | */ | |
2413 | check_group_idle: | |
7700fc4f SL |
2414 | if (cfqd->cfq_group_idle && cfqq->cfqg->nr_cfqq == 1 && |
2415 | cfqq->cfqg->dispatched && | |
2416 | !cfq_io_thinktime_big(cfqd, &cfqq->cfqg->ttime, true)) { | |
caaa5f9f JA |
2417 | cfqq = NULL; |
2418 | goto keep_queue; | |
22e2c507 JA |
2419 | } |
2420 | ||
3b18152c | 2421 | expire: |
e5ff082e | 2422 | cfq_slice_expired(cfqd, 0); |
3b18152c | 2423 | new_queue: |
718eee05 CZ |
2424 | /* |
2425 | * Current queue expired. Check if we have to switch to a new | |
2426 | * service tree | |
2427 | */ | |
2428 | if (!new_cfqq) | |
cdb16e8f | 2429 | cfq_choose_cfqg(cfqd); |
718eee05 | 2430 | |
a36e71f9 | 2431 | cfqq = cfq_set_active_queue(cfqd, new_cfqq); |
22e2c507 | 2432 | keep_queue: |
3b18152c | 2433 | return cfqq; |
22e2c507 JA |
2434 | } |
2435 | ||
febffd61 | 2436 | static int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq) |
d9e7620e JA |
2437 | { |
2438 | int dispatched = 0; | |
2439 | ||
2440 | while (cfqq->next_rq) { | |
2441 | cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq); | |
2442 | dispatched++; | |
2443 | } | |
2444 | ||
2445 | BUG_ON(!list_empty(&cfqq->fifo)); | |
f04a6424 VG |
2446 | |
2447 | /* By default cfqq is not expired if it is empty. Do it explicitly */ | |
e5ff082e | 2448 | __cfq_slice_expired(cfqq->cfqd, cfqq, 0); |
d9e7620e JA |
2449 | return dispatched; |
2450 | } | |
2451 | ||
498d3aa2 JA |
2452 | /* |
2453 | * Drain our current requests. Used for barriers and when switching | |
2454 | * io schedulers on-the-fly. | |
2455 | */ | |
d9e7620e | 2456 | static int cfq_forced_dispatch(struct cfq_data *cfqd) |
1b5ed5e1 | 2457 | { |
0871714e | 2458 | struct cfq_queue *cfqq; |
d9e7620e | 2459 | int dispatched = 0; |
cdb16e8f | 2460 | |
3440c49f | 2461 | /* Expire the timeslice of the current active queue first */ |
e5ff082e | 2462 | cfq_slice_expired(cfqd, 0); |
3440c49f DS |
2463 | while ((cfqq = cfq_get_next_queue_forced(cfqd)) != NULL) { |
2464 | __cfq_set_active_queue(cfqd, cfqq); | |
f04a6424 | 2465 | dispatched += __cfq_forced_dispatch_cfqq(cfqq); |
3440c49f | 2466 | } |
1b5ed5e1 | 2467 | |
1b5ed5e1 TH |
2468 | BUG_ON(cfqd->busy_queues); |
2469 | ||
6923715a | 2470 | cfq_log(cfqd, "forced_dispatch=%d", dispatched); |
1b5ed5e1 TH |
2471 | return dispatched; |
2472 | } | |
2473 | ||
abc3c744 SL |
2474 | static inline bool cfq_slice_used_soon(struct cfq_data *cfqd, |
2475 | struct cfq_queue *cfqq) | |
2476 | { | |
2477 | /* the queue hasn't finished any request, can't estimate */ | |
2478 | if (cfq_cfqq_slice_new(cfqq)) | |
c1e44756 | 2479 | return true; |
abc3c744 SL |
2480 | if (time_after(jiffies + cfqd->cfq_slice_idle * cfqq->dispatched, |
2481 | cfqq->slice_end)) | |
c1e44756 | 2482 | return true; |
abc3c744 | 2483 | |
c1e44756 | 2484 | return false; |
abc3c744 SL |
2485 | } |
2486 | ||
0b182d61 | 2487 | static bool cfq_may_dispatch(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
2f5cb738 | 2488 | { |
2f5cb738 | 2489 | unsigned int max_dispatch; |
22e2c507 | 2490 | |
5ad531db JA |
2491 | /* |
2492 | * Drain async requests before we start sync IO | |
2493 | */ | |
53c583d2 | 2494 | if (cfq_should_idle(cfqd, cfqq) && cfqd->rq_in_flight[BLK_RW_ASYNC]) |
0b182d61 | 2495 | return false; |
5ad531db | 2496 | |
2f5cb738 JA |
2497 | /* |
2498 | * If this is an async queue and we have sync IO in flight, let it wait | |
2499 | */ | |
53c583d2 | 2500 | if (cfqd->rq_in_flight[BLK_RW_SYNC] && !cfq_cfqq_sync(cfqq)) |
0b182d61 | 2501 | return false; |
2f5cb738 | 2502 | |
abc3c744 | 2503 | max_dispatch = max_t(unsigned int, cfqd->cfq_quantum / 2, 1); |
2f5cb738 JA |
2504 | if (cfq_class_idle(cfqq)) |
2505 | max_dispatch = 1; | |
b4878f24 | 2506 | |
2f5cb738 JA |
2507 | /* |
2508 | * Does this cfqq already have too much IO in flight? | |
2509 | */ | |
2510 | if (cfqq->dispatched >= max_dispatch) { | |
ef8a41df | 2511 | bool promote_sync = false; |
2f5cb738 JA |
2512 | /* |
2513 | * idle queue must always only have a single IO in flight | |
2514 | */ | |
3ed9a296 | 2515 | if (cfq_class_idle(cfqq)) |
0b182d61 | 2516 | return false; |
3ed9a296 | 2517 | |
ef8a41df | 2518 | /* |
c4ade94f LS |
2519 | * If there is only one sync queue |
2520 | * we can ignore async queue here and give the sync | |
ef8a41df SL |
2521 | * queue no dispatch limit. The reason is a sync queue can |
2522 | * preempt async queue, limiting the sync queue doesn't make | |
2523 | * sense. This is useful for aiostress test. | |
2524 | */ | |
c4ade94f LS |
2525 | if (cfq_cfqq_sync(cfqq) && cfqd->busy_sync_queues == 1) |
2526 | promote_sync = true; | |
ef8a41df | 2527 | |
2f5cb738 JA |
2528 | /* |
2529 | * We have other queues, don't allow more IO from this one | |
2530 | */ | |
ef8a41df SL |
2531 | if (cfqd->busy_queues > 1 && cfq_slice_used_soon(cfqd, cfqq) && |
2532 | !promote_sync) | |
0b182d61 | 2533 | return false; |
9ede209e | 2534 | |
365722bb | 2535 | /* |
474b18cc | 2536 | * Sole queue user, no limit |
365722bb | 2537 | */ |
ef8a41df | 2538 | if (cfqd->busy_queues == 1 || promote_sync) |
abc3c744 SL |
2539 | max_dispatch = -1; |
2540 | else | |
2541 | /* | |
2542 | * Normally we start throttling cfqq when cfq_quantum/2 | |
2543 | * requests have been dispatched. But we can drive | |
2544 | * deeper queue depths at the beginning of slice | |
2545 | * subjected to upper limit of cfq_quantum. | |
2546 | * */ | |
2547 | max_dispatch = cfqd->cfq_quantum; | |
8e296755 JA |
2548 | } |
2549 | ||
2550 | /* | |
2551 | * Async queues must wait a bit before being allowed dispatch. | |
2552 | * We also ramp up the dispatch depth gradually for async IO, | |
2553 | * based on the last sync IO we serviced | |
2554 | */ | |
963b72fc | 2555 | if (!cfq_cfqq_sync(cfqq) && cfqd->cfq_latency) { |
573412b2 | 2556 | unsigned long last_sync = jiffies - cfqd->last_delayed_sync; |
8e296755 | 2557 | unsigned int depth; |
365722bb | 2558 | |
61f0c1dc | 2559 | depth = last_sync / cfqd->cfq_slice[1]; |
e00c54c3 JA |
2560 | if (!depth && !cfqq->dispatched) |
2561 | depth = 1; | |
8e296755 JA |
2562 | if (depth < max_dispatch) |
2563 | max_dispatch = depth; | |
2f5cb738 | 2564 | } |
3ed9a296 | 2565 | |
0b182d61 JA |
2566 | /* |
2567 | * If we're below the current max, allow a dispatch | |
2568 | */ | |
2569 | return cfqq->dispatched < max_dispatch; | |
2570 | } | |
2571 | ||
2572 | /* | |
2573 | * Dispatch a request from cfqq, moving them to the request queue | |
2574 | * dispatch list. | |
2575 | */ | |
2576 | static bool cfq_dispatch_request(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
2577 | { | |
2578 | struct request *rq; | |
2579 | ||
2580 | BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list)); | |
2581 | ||
2582 | if (!cfq_may_dispatch(cfqd, cfqq)) | |
2583 | return false; | |
2584 | ||
2585 | /* | |
2586 | * follow expired path, else get first next available | |
2587 | */ | |
2588 | rq = cfq_check_fifo(cfqq); | |
2589 | if (!rq) | |
2590 | rq = cfqq->next_rq; | |
2591 | ||
2592 | /* | |
2593 | * insert request into driver dispatch list | |
2594 | */ | |
2595 | cfq_dispatch_insert(cfqd->queue, rq); | |
2596 | ||
2597 | if (!cfqd->active_cic) { | |
c5869807 | 2598 | struct cfq_io_cq *cic = RQ_CIC(rq); |
0b182d61 | 2599 | |
c5869807 | 2600 | atomic_long_inc(&cic->icq.ioc->refcount); |
0b182d61 JA |
2601 | cfqd->active_cic = cic; |
2602 | } | |
2603 | ||
2604 | return true; | |
2605 | } | |
2606 | ||
2607 | /* | |
2608 | * Find the cfqq that we need to service and move a request from that to the | |
2609 | * dispatch list | |
2610 | */ | |
2611 | static int cfq_dispatch_requests(struct request_queue *q, int force) | |
2612 | { | |
2613 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
2614 | struct cfq_queue *cfqq; | |
2615 | ||
2616 | if (!cfqd->busy_queues) | |
2617 | return 0; | |
2618 | ||
2619 | if (unlikely(force)) | |
2620 | return cfq_forced_dispatch(cfqd); | |
2621 | ||
2622 | cfqq = cfq_select_queue(cfqd); | |
2623 | if (!cfqq) | |
8e296755 JA |
2624 | return 0; |
2625 | ||
2f5cb738 | 2626 | /* |
0b182d61 | 2627 | * Dispatch a request from this cfqq, if it is allowed |
2f5cb738 | 2628 | */ |
0b182d61 JA |
2629 | if (!cfq_dispatch_request(cfqd, cfqq)) |
2630 | return 0; | |
2631 | ||
2f5cb738 | 2632 | cfqq->slice_dispatch++; |
b029195d | 2633 | cfq_clear_cfqq_must_dispatch(cfqq); |
22e2c507 | 2634 | |
2f5cb738 JA |
2635 | /* |
2636 | * expire an async queue immediately if it has used up its slice. idle | |
2637 | * queue always expire after 1 dispatch round. | |
2638 | */ | |
2639 | if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) && | |
2640 | cfqq->slice_dispatch >= cfq_prio_to_maxrq(cfqd, cfqq)) || | |
2641 | cfq_class_idle(cfqq))) { | |
2642 | cfqq->slice_end = jiffies + 1; | |
e5ff082e | 2643 | cfq_slice_expired(cfqd, 0); |
1da177e4 LT |
2644 | } |
2645 | ||
b217a903 | 2646 | cfq_log_cfqq(cfqd, cfqq, "dispatched a request"); |
2f5cb738 | 2647 | return 1; |
1da177e4 LT |
2648 | } |
2649 | ||
1da177e4 | 2650 | /* |
5e705374 JA |
2651 | * task holds one reference to the queue, dropped when task exits. each rq |
2652 | * in-flight on this queue also holds a reference, dropped when rq is freed. | |
1da177e4 | 2653 | * |
b1c35769 | 2654 | * Each cfq queue took a reference on the parent group. Drop it now. |
1da177e4 LT |
2655 | * queue lock must be held here. |
2656 | */ | |
2657 | static void cfq_put_queue(struct cfq_queue *cfqq) | |
2658 | { | |
22e2c507 | 2659 | struct cfq_data *cfqd = cfqq->cfqd; |
0bbfeb83 | 2660 | struct cfq_group *cfqg; |
22e2c507 | 2661 | |
30d7b944 | 2662 | BUG_ON(cfqq->ref <= 0); |
1da177e4 | 2663 | |
30d7b944 SL |
2664 | cfqq->ref--; |
2665 | if (cfqq->ref) | |
1da177e4 LT |
2666 | return; |
2667 | ||
7b679138 | 2668 | cfq_log_cfqq(cfqd, cfqq, "put_queue"); |
1da177e4 | 2669 | BUG_ON(rb_first(&cfqq->sort_list)); |
22e2c507 | 2670 | BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]); |
b1c35769 | 2671 | cfqg = cfqq->cfqg; |
1da177e4 | 2672 | |
28f95cbc | 2673 | if (unlikely(cfqd->active_queue == cfqq)) { |
e5ff082e | 2674 | __cfq_slice_expired(cfqd, cfqq, 0); |
23e018a1 | 2675 | cfq_schedule_dispatch(cfqd); |
28f95cbc | 2676 | } |
22e2c507 | 2677 | |
f04a6424 | 2678 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
1da177e4 | 2679 | kmem_cache_free(cfq_pool, cfqq); |
b1c35769 | 2680 | cfq_put_cfqg(cfqg); |
1da177e4 LT |
2681 | } |
2682 | ||
d02a2c07 | 2683 | static void cfq_put_cooperator(struct cfq_queue *cfqq) |
1da177e4 | 2684 | { |
df5fe3e8 JM |
2685 | struct cfq_queue *__cfqq, *next; |
2686 | ||
df5fe3e8 JM |
2687 | /* |
2688 | * If this queue was scheduled to merge with another queue, be | |
2689 | * sure to drop the reference taken on that queue (and others in | |
2690 | * the merge chain). See cfq_setup_merge and cfq_merge_cfqqs. | |
2691 | */ | |
2692 | __cfqq = cfqq->new_cfqq; | |
2693 | while (__cfqq) { | |
2694 | if (__cfqq == cfqq) { | |
2695 | WARN(1, "cfqq->new_cfqq loop detected\n"); | |
2696 | break; | |
2697 | } | |
2698 | next = __cfqq->new_cfqq; | |
2699 | cfq_put_queue(__cfqq); | |
2700 | __cfqq = next; | |
2701 | } | |
d02a2c07 SL |
2702 | } |
2703 | ||
2704 | static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
2705 | { | |
2706 | if (unlikely(cfqq == cfqd->active_queue)) { | |
2707 | __cfq_slice_expired(cfqd, cfqq, 0); | |
2708 | cfq_schedule_dispatch(cfqd); | |
2709 | } | |
2710 | ||
2711 | cfq_put_cooperator(cfqq); | |
df5fe3e8 | 2712 | |
89850f7e JA |
2713 | cfq_put_queue(cfqq); |
2714 | } | |
22e2c507 | 2715 | |
9b84cacd TH |
2716 | static void cfq_init_icq(struct io_cq *icq) |
2717 | { | |
2718 | struct cfq_io_cq *cic = icq_to_cic(icq); | |
2719 | ||
2720 | cic->ttime.last_end_request = jiffies; | |
2721 | } | |
2722 | ||
c5869807 | 2723 | static void cfq_exit_icq(struct io_cq *icq) |
89850f7e | 2724 | { |
c5869807 | 2725 | struct cfq_io_cq *cic = icq_to_cic(icq); |
283287a5 | 2726 | struct cfq_data *cfqd = cic_to_cfqd(cic); |
4faa3c81 | 2727 | |
ff6657c6 JA |
2728 | if (cic->cfqq[BLK_RW_ASYNC]) { |
2729 | cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_ASYNC]); | |
2730 | cic->cfqq[BLK_RW_ASYNC] = NULL; | |
12a05732 AV |
2731 | } |
2732 | ||
ff6657c6 JA |
2733 | if (cic->cfqq[BLK_RW_SYNC]) { |
2734 | cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_SYNC]); | |
2735 | cic->cfqq[BLK_RW_SYNC] = NULL; | |
12a05732 | 2736 | } |
89850f7e JA |
2737 | } |
2738 | ||
fd0928df | 2739 | static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc) |
22e2c507 JA |
2740 | { |
2741 | struct task_struct *tsk = current; | |
2742 | int ioprio_class; | |
2743 | ||
3b18152c | 2744 | if (!cfq_cfqq_prio_changed(cfqq)) |
22e2c507 JA |
2745 | return; |
2746 | ||
fd0928df | 2747 | ioprio_class = IOPRIO_PRIO_CLASS(ioc->ioprio); |
22e2c507 | 2748 | switch (ioprio_class) { |
fe094d98 JA |
2749 | default: |
2750 | printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class); | |
2751 | case IOPRIO_CLASS_NONE: | |
2752 | /* | |
6d63c275 | 2753 | * no prio set, inherit CPU scheduling settings |
fe094d98 JA |
2754 | */ |
2755 | cfqq->ioprio = task_nice_ioprio(tsk); | |
6d63c275 | 2756 | cfqq->ioprio_class = task_nice_ioclass(tsk); |
fe094d98 JA |
2757 | break; |
2758 | case IOPRIO_CLASS_RT: | |
2759 | cfqq->ioprio = task_ioprio(ioc); | |
2760 | cfqq->ioprio_class = IOPRIO_CLASS_RT; | |
2761 | break; | |
2762 | case IOPRIO_CLASS_BE: | |
2763 | cfqq->ioprio = task_ioprio(ioc); | |
2764 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
2765 | break; | |
2766 | case IOPRIO_CLASS_IDLE: | |
2767 | cfqq->ioprio_class = IOPRIO_CLASS_IDLE; | |
2768 | cfqq->ioprio = 7; | |
2769 | cfq_clear_cfqq_idle_window(cfqq); | |
2770 | break; | |
22e2c507 JA |
2771 | } |
2772 | ||
2773 | /* | |
2774 | * keep track of original prio settings in case we have to temporarily | |
2775 | * elevate the priority of this queue | |
2776 | */ | |
2777 | cfqq->org_ioprio = cfqq->ioprio; | |
3b18152c | 2778 | cfq_clear_cfqq_prio_changed(cfqq); |
22e2c507 JA |
2779 | } |
2780 | ||
c5869807 | 2781 | static void changed_ioprio(struct cfq_io_cq *cic) |
22e2c507 | 2782 | { |
bca4b914 | 2783 | struct cfq_data *cfqd = cic_to_cfqd(cic); |
478a82b0 | 2784 | struct cfq_queue *cfqq; |
35e6077c | 2785 | |
caaa5f9f JA |
2786 | if (unlikely(!cfqd)) |
2787 | return; | |
2788 | ||
ff6657c6 | 2789 | cfqq = cic->cfqq[BLK_RW_ASYNC]; |
caaa5f9f JA |
2790 | if (cfqq) { |
2791 | struct cfq_queue *new_cfqq; | |
c5869807 | 2792 | new_cfqq = cfq_get_queue(cfqd, BLK_RW_ASYNC, cic->icq.ioc, |
ff6657c6 | 2793 | GFP_ATOMIC); |
caaa5f9f | 2794 | if (new_cfqq) { |
ff6657c6 | 2795 | cic->cfqq[BLK_RW_ASYNC] = new_cfqq; |
caaa5f9f JA |
2796 | cfq_put_queue(cfqq); |
2797 | } | |
22e2c507 | 2798 | } |
caaa5f9f | 2799 | |
ff6657c6 | 2800 | cfqq = cic->cfqq[BLK_RW_SYNC]; |
caaa5f9f JA |
2801 | if (cfqq) |
2802 | cfq_mark_cfqq_prio_changed(cfqq); | |
22e2c507 JA |
2803 | } |
2804 | ||
d5036d77 | 2805 | static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
a6151c3a | 2806 | pid_t pid, bool is_sync) |
d5036d77 JA |
2807 | { |
2808 | RB_CLEAR_NODE(&cfqq->rb_node); | |
2809 | RB_CLEAR_NODE(&cfqq->p_node); | |
2810 | INIT_LIST_HEAD(&cfqq->fifo); | |
2811 | ||
30d7b944 | 2812 | cfqq->ref = 0; |
d5036d77 JA |
2813 | cfqq->cfqd = cfqd; |
2814 | ||
2815 | cfq_mark_cfqq_prio_changed(cfqq); | |
2816 | ||
2817 | if (is_sync) { | |
2818 | if (!cfq_class_idle(cfqq)) | |
2819 | cfq_mark_cfqq_idle_window(cfqq); | |
2820 | cfq_mark_cfqq_sync(cfqq); | |
2821 | } | |
2822 | cfqq->pid = pid; | |
2823 | } | |
2824 | ||
24610333 | 2825 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
c5869807 | 2826 | static void changed_cgroup(struct cfq_io_cq *cic) |
24610333 VG |
2827 | { |
2828 | struct cfq_queue *sync_cfqq = cic_to_cfqq(cic, 1); | |
bca4b914 | 2829 | struct cfq_data *cfqd = cic_to_cfqd(cic); |
24610333 VG |
2830 | struct request_queue *q; |
2831 | ||
2832 | if (unlikely(!cfqd)) | |
2833 | return; | |
2834 | ||
2835 | q = cfqd->queue; | |
2836 | ||
24610333 VG |
2837 | if (sync_cfqq) { |
2838 | /* | |
2839 | * Drop reference to sync queue. A new sync queue will be | |
2840 | * assigned in new group upon arrival of a fresh request. | |
2841 | */ | |
2842 | cfq_log_cfqq(cfqd, sync_cfqq, "changed cgroup"); | |
2843 | cic_set_cfqq(cic, NULL, 1); | |
2844 | cfq_put_queue(sync_cfqq); | |
2845 | } | |
24610333 | 2846 | } |
24610333 VG |
2847 | #endif /* CONFIG_CFQ_GROUP_IOSCHED */ |
2848 | ||
22e2c507 | 2849 | static struct cfq_queue * |
a6151c3a | 2850 | cfq_find_alloc_queue(struct cfq_data *cfqd, bool is_sync, |
fd0928df | 2851 | struct io_context *ioc, gfp_t gfp_mask) |
22e2c507 | 2852 | { |
22e2c507 | 2853 | struct cfq_queue *cfqq, *new_cfqq = NULL; |
c5869807 | 2854 | struct cfq_io_cq *cic; |
cdb16e8f | 2855 | struct cfq_group *cfqg; |
22e2c507 JA |
2856 | |
2857 | retry: | |
3e59cf9d | 2858 | cfqg = cfq_get_cfqg(cfqd); |
4ac845a2 | 2859 | cic = cfq_cic_lookup(cfqd, ioc); |
91fac317 VT |
2860 | /* cic always exists here */ |
2861 | cfqq = cic_to_cfqq(cic, is_sync); | |
22e2c507 | 2862 | |
6118b70b JA |
2863 | /* |
2864 | * Always try a new alloc if we fell back to the OOM cfqq | |
2865 | * originally, since it should just be a temporary situation. | |
2866 | */ | |
2867 | if (!cfqq || cfqq == &cfqd->oom_cfqq) { | |
2868 | cfqq = NULL; | |
22e2c507 JA |
2869 | if (new_cfqq) { |
2870 | cfqq = new_cfqq; | |
2871 | new_cfqq = NULL; | |
2872 | } else if (gfp_mask & __GFP_WAIT) { | |
2873 | spin_unlock_irq(cfqd->queue->queue_lock); | |
94f6030c | 2874 | new_cfqq = kmem_cache_alloc_node(cfq_pool, |
6118b70b | 2875 | gfp_mask | __GFP_ZERO, |
94f6030c | 2876 | cfqd->queue->node); |
22e2c507 | 2877 | spin_lock_irq(cfqd->queue->queue_lock); |
6118b70b JA |
2878 | if (new_cfqq) |
2879 | goto retry; | |
22e2c507 | 2880 | } else { |
94f6030c CL |
2881 | cfqq = kmem_cache_alloc_node(cfq_pool, |
2882 | gfp_mask | __GFP_ZERO, | |
2883 | cfqd->queue->node); | |
22e2c507 JA |
2884 | } |
2885 | ||
6118b70b JA |
2886 | if (cfqq) { |
2887 | cfq_init_cfqq(cfqd, cfqq, current->pid, is_sync); | |
2888 | cfq_init_prio_data(cfqq, ioc); | |
cdb16e8f | 2889 | cfq_link_cfqq_cfqg(cfqq, cfqg); |
6118b70b JA |
2890 | cfq_log_cfqq(cfqd, cfqq, "alloced"); |
2891 | } else | |
2892 | cfqq = &cfqd->oom_cfqq; | |
22e2c507 JA |
2893 | } |
2894 | ||
2895 | if (new_cfqq) | |
2896 | kmem_cache_free(cfq_pool, new_cfqq); | |
2897 | ||
22e2c507 JA |
2898 | return cfqq; |
2899 | } | |
2900 | ||
c2dea2d1 VT |
2901 | static struct cfq_queue ** |
2902 | cfq_async_queue_prio(struct cfq_data *cfqd, int ioprio_class, int ioprio) | |
2903 | { | |
fe094d98 | 2904 | switch (ioprio_class) { |
c2dea2d1 VT |
2905 | case IOPRIO_CLASS_RT: |
2906 | return &cfqd->async_cfqq[0][ioprio]; | |
2907 | case IOPRIO_CLASS_BE: | |
2908 | return &cfqd->async_cfqq[1][ioprio]; | |
2909 | case IOPRIO_CLASS_IDLE: | |
2910 | return &cfqd->async_idle_cfqq; | |
2911 | default: | |
2912 | BUG(); | |
2913 | } | |
2914 | } | |
2915 | ||
15c31be4 | 2916 | static struct cfq_queue * |
a6151c3a | 2917 | cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct io_context *ioc, |
15c31be4 JA |
2918 | gfp_t gfp_mask) |
2919 | { | |
fd0928df JA |
2920 | const int ioprio = task_ioprio(ioc); |
2921 | const int ioprio_class = task_ioprio_class(ioc); | |
c2dea2d1 | 2922 | struct cfq_queue **async_cfqq = NULL; |
15c31be4 JA |
2923 | struct cfq_queue *cfqq = NULL; |
2924 | ||
c2dea2d1 VT |
2925 | if (!is_sync) { |
2926 | async_cfqq = cfq_async_queue_prio(cfqd, ioprio_class, ioprio); | |
2927 | cfqq = *async_cfqq; | |
2928 | } | |
2929 | ||
6118b70b | 2930 | if (!cfqq) |
fd0928df | 2931 | cfqq = cfq_find_alloc_queue(cfqd, is_sync, ioc, gfp_mask); |
15c31be4 JA |
2932 | |
2933 | /* | |
2934 | * pin the queue now that it's allocated, scheduler exit will prune it | |
2935 | */ | |
c2dea2d1 | 2936 | if (!is_sync && !(*async_cfqq)) { |
30d7b944 | 2937 | cfqq->ref++; |
c2dea2d1 | 2938 | *async_cfqq = cfqq; |
15c31be4 JA |
2939 | } |
2940 | ||
30d7b944 | 2941 | cfqq->ref++; |
15c31be4 JA |
2942 | return cfqq; |
2943 | } | |
2944 | ||
22e2c507 | 2945 | static void |
383cd721 | 2946 | __cfq_update_io_thinktime(struct cfq_ttime *ttime, unsigned long slice_idle) |
1da177e4 | 2947 | { |
383cd721 SL |
2948 | unsigned long elapsed = jiffies - ttime->last_end_request; |
2949 | elapsed = min(elapsed, 2UL * slice_idle); | |
db3b5848 | 2950 | |
383cd721 SL |
2951 | ttime->ttime_samples = (7*ttime->ttime_samples + 256) / 8; |
2952 | ttime->ttime_total = (7*ttime->ttime_total + 256*elapsed) / 8; | |
2953 | ttime->ttime_mean = (ttime->ttime_total + 128) / ttime->ttime_samples; | |
2954 | } | |
2955 | ||
2956 | static void | |
2957 | cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
c5869807 | 2958 | struct cfq_io_cq *cic) |
383cd721 | 2959 | { |
f5f2b6ce | 2960 | if (cfq_cfqq_sync(cfqq)) { |
383cd721 | 2961 | __cfq_update_io_thinktime(&cic->ttime, cfqd->cfq_slice_idle); |
f5f2b6ce SL |
2962 | __cfq_update_io_thinktime(&cfqq->service_tree->ttime, |
2963 | cfqd->cfq_slice_idle); | |
2964 | } | |
7700fc4f SL |
2965 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
2966 | __cfq_update_io_thinktime(&cfqq->cfqg->ttime, cfqd->cfq_group_idle); | |
2967 | #endif | |
22e2c507 | 2968 | } |
1da177e4 | 2969 | |
206dc69b | 2970 | static void |
b2c18e1e | 2971 | cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
6d048f53 | 2972 | struct request *rq) |
206dc69b | 2973 | { |
3dde36dd | 2974 | sector_t sdist = 0; |
41647e7a | 2975 | sector_t n_sec = blk_rq_sectors(rq); |
3dde36dd CZ |
2976 | if (cfqq->last_request_pos) { |
2977 | if (cfqq->last_request_pos < blk_rq_pos(rq)) | |
2978 | sdist = blk_rq_pos(rq) - cfqq->last_request_pos; | |
2979 | else | |
2980 | sdist = cfqq->last_request_pos - blk_rq_pos(rq); | |
2981 | } | |
206dc69b | 2982 | |
3dde36dd | 2983 | cfqq->seek_history <<= 1; |
41647e7a CZ |
2984 | if (blk_queue_nonrot(cfqd->queue)) |
2985 | cfqq->seek_history |= (n_sec < CFQQ_SECT_THR_NONROT); | |
2986 | else | |
2987 | cfqq->seek_history |= (sdist > CFQQ_SEEK_THR); | |
206dc69b | 2988 | } |
1da177e4 | 2989 | |
22e2c507 JA |
2990 | /* |
2991 | * Disable idle window if the process thinks too long or seeks so much that | |
2992 | * it doesn't matter | |
2993 | */ | |
2994 | static void | |
2995 | cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
c5869807 | 2996 | struct cfq_io_cq *cic) |
22e2c507 | 2997 | { |
7b679138 | 2998 | int old_idle, enable_idle; |
1be92f2f | 2999 | |
0871714e JA |
3000 | /* |
3001 | * Don't idle for async or idle io prio class | |
3002 | */ | |
3003 | if (!cfq_cfqq_sync(cfqq) || cfq_class_idle(cfqq)) | |
1be92f2f JA |
3004 | return; |
3005 | ||
c265a7f4 | 3006 | enable_idle = old_idle = cfq_cfqq_idle_window(cfqq); |
1da177e4 | 3007 | |
76280aff CZ |
3008 | if (cfqq->queued[0] + cfqq->queued[1] >= 4) |
3009 | cfq_mark_cfqq_deep(cfqq); | |
3010 | ||
749ef9f8 CZ |
3011 | if (cfqq->next_rq && (cfqq->next_rq->cmd_flags & REQ_NOIDLE)) |
3012 | enable_idle = 0; | |
c5869807 TH |
3013 | else if (!atomic_read(&cic->icq.ioc->nr_tasks) || |
3014 | !cfqd->cfq_slice_idle || | |
3015 | (!cfq_cfqq_deep(cfqq) && CFQQ_SEEKY(cfqq))) | |
22e2c507 | 3016 | enable_idle = 0; |
383cd721 SL |
3017 | else if (sample_valid(cic->ttime.ttime_samples)) { |
3018 | if (cic->ttime.ttime_mean > cfqd->cfq_slice_idle) | |
22e2c507 JA |
3019 | enable_idle = 0; |
3020 | else | |
3021 | enable_idle = 1; | |
1da177e4 LT |
3022 | } |
3023 | ||
7b679138 JA |
3024 | if (old_idle != enable_idle) { |
3025 | cfq_log_cfqq(cfqd, cfqq, "idle=%d", enable_idle); | |
3026 | if (enable_idle) | |
3027 | cfq_mark_cfqq_idle_window(cfqq); | |
3028 | else | |
3029 | cfq_clear_cfqq_idle_window(cfqq); | |
3030 | } | |
22e2c507 | 3031 | } |
1da177e4 | 3032 | |
22e2c507 JA |
3033 | /* |
3034 | * Check if new_cfqq should preempt the currently active queue. Return 0 for | |
3035 | * no or if we aren't sure, a 1 will cause a preempt. | |
3036 | */ | |
a6151c3a | 3037 | static bool |
22e2c507 | 3038 | cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, |
5e705374 | 3039 | struct request *rq) |
22e2c507 | 3040 | { |
6d048f53 | 3041 | struct cfq_queue *cfqq; |
22e2c507 | 3042 | |
6d048f53 JA |
3043 | cfqq = cfqd->active_queue; |
3044 | if (!cfqq) | |
a6151c3a | 3045 | return false; |
22e2c507 | 3046 | |
6d048f53 | 3047 | if (cfq_class_idle(new_cfqq)) |
a6151c3a | 3048 | return false; |
22e2c507 JA |
3049 | |
3050 | if (cfq_class_idle(cfqq)) | |
a6151c3a | 3051 | return true; |
1e3335de | 3052 | |
875feb63 DS |
3053 | /* |
3054 | * Don't allow a non-RT request to preempt an ongoing RT cfqq timeslice. | |
3055 | */ | |
3056 | if (cfq_class_rt(cfqq) && !cfq_class_rt(new_cfqq)) | |
3057 | return false; | |
3058 | ||
374f84ac JA |
3059 | /* |
3060 | * if the new request is sync, but the currently running queue is | |
3061 | * not, let the sync request have priority. | |
3062 | */ | |
5e705374 | 3063 | if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq)) |
a6151c3a | 3064 | return true; |
1e3335de | 3065 | |
8682e1f1 VG |
3066 | if (new_cfqq->cfqg != cfqq->cfqg) |
3067 | return false; | |
3068 | ||
3069 | if (cfq_slice_used(cfqq)) | |
3070 | return true; | |
3071 | ||
3072 | /* Allow preemption only if we are idling on sync-noidle tree */ | |
3073 | if (cfqd->serving_type == SYNC_NOIDLE_WORKLOAD && | |
3074 | cfqq_type(new_cfqq) == SYNC_NOIDLE_WORKLOAD && | |
3075 | new_cfqq->service_tree->count == 2 && | |
3076 | RB_EMPTY_ROOT(&cfqq->sort_list)) | |
3077 | return true; | |
3078 | ||
b53d1ed7 JA |
3079 | /* |
3080 | * So both queues are sync. Let the new request get disk time if | |
3081 | * it's a metadata request and the current queue is doing regular IO. | |
3082 | */ | |
65299a3b | 3083 | if ((rq->cmd_flags & REQ_PRIO) && !cfqq->prio_pending) |
b53d1ed7 JA |
3084 | return true; |
3085 | ||
3a9a3f6c DS |
3086 | /* |
3087 | * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice. | |
3088 | */ | |
3089 | if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq)) | |
a6151c3a | 3090 | return true; |
3a9a3f6c | 3091 | |
d2d59e18 SL |
3092 | /* An idle queue should not be idle now for some reason */ |
3093 | if (RB_EMPTY_ROOT(&cfqq->sort_list) && !cfq_should_idle(cfqd, cfqq)) | |
3094 | return true; | |
3095 | ||
1e3335de | 3096 | if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq)) |
a6151c3a | 3097 | return false; |
1e3335de JA |
3098 | |
3099 | /* | |
3100 | * if this request is as-good as one we would expect from the | |
3101 | * current cfqq, let it preempt | |
3102 | */ | |
e9ce335d | 3103 | if (cfq_rq_close(cfqd, cfqq, rq)) |
a6151c3a | 3104 | return true; |
1e3335de | 3105 | |
a6151c3a | 3106 | return false; |
22e2c507 JA |
3107 | } |
3108 | ||
3109 | /* | |
3110 | * cfqq preempts the active queue. if we allowed preempt with no slice left, | |
3111 | * let it have half of its nominal slice. | |
3112 | */ | |
3113 | static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
3114 | { | |
df0793ab SL |
3115 | enum wl_type_t old_type = cfqq_type(cfqd->active_queue); |
3116 | ||
7b679138 | 3117 | cfq_log_cfqq(cfqd, cfqq, "preempt"); |
df0793ab | 3118 | cfq_slice_expired(cfqd, 1); |
22e2c507 | 3119 | |
f8ae6e3e SL |
3120 | /* |
3121 | * workload type is changed, don't save slice, otherwise preempt | |
3122 | * doesn't happen | |
3123 | */ | |
df0793ab | 3124 | if (old_type != cfqq_type(cfqq)) |
f8ae6e3e SL |
3125 | cfqq->cfqg->saved_workload_slice = 0; |
3126 | ||
bf572256 JA |
3127 | /* |
3128 | * Put the new queue at the front of the of the current list, | |
3129 | * so we know that it will be selected next. | |
3130 | */ | |
3131 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); | |
edd75ffd JA |
3132 | |
3133 | cfq_service_tree_add(cfqd, cfqq, 1); | |
eda5e0c9 | 3134 | |
62a37f6b JT |
3135 | cfqq->slice_end = 0; |
3136 | cfq_mark_cfqq_slice_new(cfqq); | |
22e2c507 JA |
3137 | } |
3138 | ||
22e2c507 | 3139 | /* |
5e705374 | 3140 | * Called when a new fs request (rq) is added (to cfqq). Check if there's |
22e2c507 JA |
3141 | * something we should do about it |
3142 | */ | |
3143 | static void | |
5e705374 JA |
3144 | cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
3145 | struct request *rq) | |
22e2c507 | 3146 | { |
c5869807 | 3147 | struct cfq_io_cq *cic = RQ_CIC(rq); |
12e9fddd | 3148 | |
45333d5a | 3149 | cfqd->rq_queued++; |
65299a3b CH |
3150 | if (rq->cmd_flags & REQ_PRIO) |
3151 | cfqq->prio_pending++; | |
374f84ac | 3152 | |
383cd721 | 3153 | cfq_update_io_thinktime(cfqd, cfqq, cic); |
b2c18e1e | 3154 | cfq_update_io_seektime(cfqd, cfqq, rq); |
9c2c38a1 JA |
3155 | cfq_update_idle_window(cfqd, cfqq, cic); |
3156 | ||
b2c18e1e | 3157 | cfqq->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq); |
22e2c507 JA |
3158 | |
3159 | if (cfqq == cfqd->active_queue) { | |
3160 | /* | |
b029195d JA |
3161 | * Remember that we saw a request from this process, but |
3162 | * don't start queuing just yet. Otherwise we risk seeing lots | |
3163 | * of tiny requests, because we disrupt the normal plugging | |
d6ceb25e JA |
3164 | * and merging. If the request is already larger than a single |
3165 | * page, let it rip immediately. For that case we assume that | |
2d870722 JA |
3166 | * merging is already done. Ditto for a busy system that |
3167 | * has other work pending, don't risk delaying until the | |
3168 | * idle timer unplug to continue working. | |
22e2c507 | 3169 | */ |
d6ceb25e | 3170 | if (cfq_cfqq_wait_request(cfqq)) { |
2d870722 JA |
3171 | if (blk_rq_bytes(rq) > PAGE_CACHE_SIZE || |
3172 | cfqd->busy_queues > 1) { | |
812df48d | 3173 | cfq_del_timer(cfqd, cfqq); |
554554f6 | 3174 | cfq_clear_cfqq_wait_request(cfqq); |
24ecfbe2 | 3175 | __blk_run_queue(cfqd->queue); |
a11cdaa7 | 3176 | } else { |
e98ef89b | 3177 | cfq_blkiocg_update_idle_time_stats( |
a11cdaa7 | 3178 | &cfqq->cfqg->blkg); |
bf791937 | 3179 | cfq_mark_cfqq_must_dispatch(cfqq); |
a11cdaa7 | 3180 | } |
d6ceb25e | 3181 | } |
5e705374 | 3182 | } else if (cfq_should_preempt(cfqd, cfqq, rq)) { |
22e2c507 JA |
3183 | /* |
3184 | * not the active queue - expire current slice if it is | |
3185 | * idle and has expired it's mean thinktime or this new queue | |
3a9a3f6c DS |
3186 | * has some old slice time left and is of higher priority or |
3187 | * this new queue is RT and the current one is BE | |
22e2c507 JA |
3188 | */ |
3189 | cfq_preempt_queue(cfqd, cfqq); | |
24ecfbe2 | 3190 | __blk_run_queue(cfqd->queue); |
22e2c507 | 3191 | } |
1da177e4 LT |
3192 | } |
3193 | ||
165125e1 | 3194 | static void cfq_insert_request(struct request_queue *q, struct request *rq) |
1da177e4 | 3195 | { |
b4878f24 | 3196 | struct cfq_data *cfqd = q->elevator->elevator_data; |
5e705374 | 3197 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 | 3198 | |
7b679138 | 3199 | cfq_log_cfqq(cfqd, cfqq, "insert_request"); |
c5869807 | 3200 | cfq_init_prio_data(cfqq, RQ_CIC(rq)->icq.ioc); |
1da177e4 | 3201 | |
30996f40 | 3202 | rq_set_fifo_time(rq, jiffies + cfqd->cfq_fifo_expire[rq_is_sync(rq)]); |
22e2c507 | 3203 | list_add_tail(&rq->queuelist, &cfqq->fifo); |
aa6f6a3d | 3204 | cfq_add_rq_rb(rq); |
e98ef89b | 3205 | cfq_blkiocg_update_io_add_stats(&(RQ_CFQG(rq))->blkg, |
cdc1184c DS |
3206 | &cfqd->serving_group->blkg, rq_data_dir(rq), |
3207 | rq_is_sync(rq)); | |
5e705374 | 3208 | cfq_rq_enqueued(cfqd, cfqq, rq); |
1da177e4 LT |
3209 | } |
3210 | ||
45333d5a AC |
3211 | /* |
3212 | * Update hw_tag based on peak queue depth over 50 samples under | |
3213 | * sufficient load. | |
3214 | */ | |
3215 | static void cfq_update_hw_tag(struct cfq_data *cfqd) | |
3216 | { | |
1a1238a7 SL |
3217 | struct cfq_queue *cfqq = cfqd->active_queue; |
3218 | ||
53c583d2 CZ |
3219 | if (cfqd->rq_in_driver > cfqd->hw_tag_est_depth) |
3220 | cfqd->hw_tag_est_depth = cfqd->rq_in_driver; | |
e459dd08 CZ |
3221 | |
3222 | if (cfqd->hw_tag == 1) | |
3223 | return; | |
45333d5a AC |
3224 | |
3225 | if (cfqd->rq_queued <= CFQ_HW_QUEUE_MIN && | |
53c583d2 | 3226 | cfqd->rq_in_driver <= CFQ_HW_QUEUE_MIN) |
45333d5a AC |
3227 | return; |
3228 | ||
1a1238a7 SL |
3229 | /* |
3230 | * If active queue hasn't enough requests and can idle, cfq might not | |
3231 | * dispatch sufficient requests to hardware. Don't zero hw_tag in this | |
3232 | * case | |
3233 | */ | |
3234 | if (cfqq && cfq_cfqq_idle_window(cfqq) && | |
3235 | cfqq->dispatched + cfqq->queued[0] + cfqq->queued[1] < | |
53c583d2 | 3236 | CFQ_HW_QUEUE_MIN && cfqd->rq_in_driver < CFQ_HW_QUEUE_MIN) |
1a1238a7 SL |
3237 | return; |
3238 | ||
45333d5a AC |
3239 | if (cfqd->hw_tag_samples++ < 50) |
3240 | return; | |
3241 | ||
e459dd08 | 3242 | if (cfqd->hw_tag_est_depth >= CFQ_HW_QUEUE_MIN) |
45333d5a AC |
3243 | cfqd->hw_tag = 1; |
3244 | else | |
3245 | cfqd->hw_tag = 0; | |
45333d5a AC |
3246 | } |
3247 | ||
7667aa06 VG |
3248 | static bool cfq_should_wait_busy(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
3249 | { | |
c5869807 | 3250 | struct cfq_io_cq *cic = cfqd->active_cic; |
7667aa06 | 3251 | |
02a8f01b JT |
3252 | /* If the queue already has requests, don't wait */ |
3253 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) | |
3254 | return false; | |
3255 | ||
7667aa06 VG |
3256 | /* If there are other queues in the group, don't wait */ |
3257 | if (cfqq->cfqg->nr_cfqq > 1) | |
3258 | return false; | |
3259 | ||
7700fc4f SL |
3260 | /* the only queue in the group, but think time is big */ |
3261 | if (cfq_io_thinktime_big(cfqd, &cfqq->cfqg->ttime, true)) | |
3262 | return false; | |
3263 | ||
7667aa06 VG |
3264 | if (cfq_slice_used(cfqq)) |
3265 | return true; | |
3266 | ||
3267 | /* if slice left is less than think time, wait busy */ | |
383cd721 SL |
3268 | if (cic && sample_valid(cic->ttime.ttime_samples) |
3269 | && (cfqq->slice_end - jiffies < cic->ttime.ttime_mean)) | |
7667aa06 VG |
3270 | return true; |
3271 | ||
3272 | /* | |
3273 | * If think times is less than a jiffy than ttime_mean=0 and above | |
3274 | * will not be true. It might happen that slice has not expired yet | |
3275 | * but will expire soon (4-5 ns) during select_queue(). To cover the | |
3276 | * case where think time is less than a jiffy, mark the queue wait | |
3277 | * busy if only 1 jiffy is left in the slice. | |
3278 | */ | |
3279 | if (cfqq->slice_end - jiffies == 1) | |
3280 | return true; | |
3281 | ||
3282 | return false; | |
3283 | } | |
3284 | ||
165125e1 | 3285 | static void cfq_completed_request(struct request_queue *q, struct request *rq) |
1da177e4 | 3286 | { |
5e705374 | 3287 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
b4878f24 | 3288 | struct cfq_data *cfqd = cfqq->cfqd; |
5380a101 | 3289 | const int sync = rq_is_sync(rq); |
b4878f24 | 3290 | unsigned long now; |
1da177e4 | 3291 | |
b4878f24 | 3292 | now = jiffies; |
33659ebb CH |
3293 | cfq_log_cfqq(cfqd, cfqq, "complete rqnoidle %d", |
3294 | !!(rq->cmd_flags & REQ_NOIDLE)); | |
1da177e4 | 3295 | |
45333d5a AC |
3296 | cfq_update_hw_tag(cfqd); |
3297 | ||
53c583d2 | 3298 | WARN_ON(!cfqd->rq_in_driver); |
6d048f53 | 3299 | WARN_ON(!cfqq->dispatched); |
53c583d2 | 3300 | cfqd->rq_in_driver--; |
6d048f53 | 3301 | cfqq->dispatched--; |
80bdf0c7 | 3302 | (RQ_CFQG(rq))->dispatched--; |
e98ef89b VG |
3303 | cfq_blkiocg_update_completion_stats(&cfqq->cfqg->blkg, |
3304 | rq_start_time_ns(rq), rq_io_start_time_ns(rq), | |
3305 | rq_data_dir(rq), rq_is_sync(rq)); | |
1da177e4 | 3306 | |
53c583d2 | 3307 | cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]--; |
3ed9a296 | 3308 | |
365722bb | 3309 | if (sync) { |
f5f2b6ce SL |
3310 | struct cfq_rb_root *service_tree; |
3311 | ||
383cd721 | 3312 | RQ_CIC(rq)->ttime.last_end_request = now; |
f5f2b6ce SL |
3313 | |
3314 | if (cfq_cfqq_on_rr(cfqq)) | |
3315 | service_tree = cfqq->service_tree; | |
3316 | else | |
3317 | service_tree = service_tree_for(cfqq->cfqg, | |
3318 | cfqq_prio(cfqq), cfqq_type(cfqq)); | |
3319 | service_tree->ttime.last_end_request = now; | |
573412b2 CZ |
3320 | if (!time_after(rq->start_time + cfqd->cfq_fifo_expire[1], now)) |
3321 | cfqd->last_delayed_sync = now; | |
365722bb | 3322 | } |
caaa5f9f | 3323 | |
7700fc4f SL |
3324 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
3325 | cfqq->cfqg->ttime.last_end_request = now; | |
3326 | #endif | |
3327 | ||
caaa5f9f JA |
3328 | /* |
3329 | * If this is the active queue, check if it needs to be expired, | |
3330 | * or if we want to idle in case it has no pending requests. | |
3331 | */ | |
3332 | if (cfqd->active_queue == cfqq) { | |
a36e71f9 JA |
3333 | const bool cfqq_empty = RB_EMPTY_ROOT(&cfqq->sort_list); |
3334 | ||
44f7c160 JA |
3335 | if (cfq_cfqq_slice_new(cfqq)) { |
3336 | cfq_set_prio_slice(cfqd, cfqq); | |
3337 | cfq_clear_cfqq_slice_new(cfqq); | |
3338 | } | |
f75edf2d VG |
3339 | |
3340 | /* | |
7667aa06 VG |
3341 | * Should we wait for next request to come in before we expire |
3342 | * the queue. | |
f75edf2d | 3343 | */ |
7667aa06 | 3344 | if (cfq_should_wait_busy(cfqd, cfqq)) { |
80bdf0c7 VG |
3345 | unsigned long extend_sl = cfqd->cfq_slice_idle; |
3346 | if (!cfqd->cfq_slice_idle) | |
3347 | extend_sl = cfqd->cfq_group_idle; | |
3348 | cfqq->slice_end = jiffies + extend_sl; | |
f75edf2d | 3349 | cfq_mark_cfqq_wait_busy(cfqq); |
b1ffe737 | 3350 | cfq_log_cfqq(cfqd, cfqq, "will busy wait"); |
f75edf2d VG |
3351 | } |
3352 | ||
a36e71f9 | 3353 | /* |
8e550632 CZ |
3354 | * Idling is not enabled on: |
3355 | * - expired queues | |
3356 | * - idle-priority queues | |
3357 | * - async queues | |
3358 | * - queues with still some requests queued | |
3359 | * - when there is a close cooperator | |
a36e71f9 | 3360 | */ |
0871714e | 3361 | if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq)) |
e5ff082e | 3362 | cfq_slice_expired(cfqd, 1); |
8e550632 CZ |
3363 | else if (sync && cfqq_empty && |
3364 | !cfq_close_cooperator(cfqd, cfqq)) { | |
749ef9f8 | 3365 | cfq_arm_slice_timer(cfqd); |
8e550632 | 3366 | } |
caaa5f9f | 3367 | } |
6d048f53 | 3368 | |
53c583d2 | 3369 | if (!cfqd->rq_in_driver) |
23e018a1 | 3370 | cfq_schedule_dispatch(cfqd); |
1da177e4 LT |
3371 | } |
3372 | ||
89850f7e | 3373 | static inline int __cfq_may_queue(struct cfq_queue *cfqq) |
22e2c507 | 3374 | { |
1b379d8d | 3375 | if (cfq_cfqq_wait_request(cfqq) && !cfq_cfqq_must_alloc_slice(cfqq)) { |
3b18152c | 3376 | cfq_mark_cfqq_must_alloc_slice(cfqq); |
22e2c507 | 3377 | return ELV_MQUEUE_MUST; |
3b18152c | 3378 | } |
1da177e4 | 3379 | |
22e2c507 | 3380 | return ELV_MQUEUE_MAY; |
22e2c507 JA |
3381 | } |
3382 | ||
165125e1 | 3383 | static int cfq_may_queue(struct request_queue *q, int rw) |
22e2c507 JA |
3384 | { |
3385 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
3386 | struct task_struct *tsk = current; | |
c5869807 | 3387 | struct cfq_io_cq *cic; |
22e2c507 JA |
3388 | struct cfq_queue *cfqq; |
3389 | ||
3390 | /* | |
3391 | * don't force setup of a queue from here, as a call to may_queue | |
3392 | * does not necessarily imply that a request actually will be queued. | |
3393 | * so just lookup a possibly existing queue, or return 'may queue' | |
3394 | * if that fails | |
3395 | */ | |
4ac845a2 | 3396 | cic = cfq_cic_lookup(cfqd, tsk->io_context); |
91fac317 VT |
3397 | if (!cic) |
3398 | return ELV_MQUEUE_MAY; | |
3399 | ||
b0b78f81 | 3400 | cfqq = cic_to_cfqq(cic, rw_is_sync(rw)); |
22e2c507 | 3401 | if (cfqq) { |
c5869807 | 3402 | cfq_init_prio_data(cfqq, cic->icq.ioc); |
22e2c507 | 3403 | |
89850f7e | 3404 | return __cfq_may_queue(cfqq); |
22e2c507 JA |
3405 | } |
3406 | ||
3407 | return ELV_MQUEUE_MAY; | |
1da177e4 LT |
3408 | } |
3409 | ||
1da177e4 LT |
3410 | /* |
3411 | * queue lock held here | |
3412 | */ | |
bb37b94c | 3413 | static void cfq_put_request(struct request *rq) |
1da177e4 | 3414 | { |
5e705374 | 3415 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
1da177e4 | 3416 | |
5e705374 | 3417 | if (cfqq) { |
22e2c507 | 3418 | const int rw = rq_data_dir(rq); |
1da177e4 | 3419 | |
22e2c507 JA |
3420 | BUG_ON(!cfqq->allocated[rw]); |
3421 | cfqq->allocated[rw]--; | |
1da177e4 | 3422 | |
7f1dc8a2 VG |
3423 | /* Put down rq reference on cfqg */ |
3424 | cfq_put_cfqg(RQ_CFQG(rq)); | |
a612fddf TH |
3425 | rq->elv.priv[0] = NULL; |
3426 | rq->elv.priv[1] = NULL; | |
7f1dc8a2 | 3427 | |
1da177e4 LT |
3428 | cfq_put_queue(cfqq); |
3429 | } | |
3430 | } | |
3431 | ||
df5fe3e8 | 3432 | static struct cfq_queue * |
c5869807 | 3433 | cfq_merge_cfqqs(struct cfq_data *cfqd, struct cfq_io_cq *cic, |
df5fe3e8 JM |
3434 | struct cfq_queue *cfqq) |
3435 | { | |
3436 | cfq_log_cfqq(cfqd, cfqq, "merging with queue %p", cfqq->new_cfqq); | |
3437 | cic_set_cfqq(cic, cfqq->new_cfqq, 1); | |
b3b6d040 | 3438 | cfq_mark_cfqq_coop(cfqq->new_cfqq); |
df5fe3e8 JM |
3439 | cfq_put_queue(cfqq); |
3440 | return cic_to_cfqq(cic, 1); | |
3441 | } | |
3442 | ||
e6c5bc73 JM |
3443 | /* |
3444 | * Returns NULL if a new cfqq should be allocated, or the old cfqq if this | |
3445 | * was the last process referring to said cfqq. | |
3446 | */ | |
3447 | static struct cfq_queue * | |
c5869807 | 3448 | split_cfqq(struct cfq_io_cq *cic, struct cfq_queue *cfqq) |
e6c5bc73 JM |
3449 | { |
3450 | if (cfqq_process_refs(cfqq) == 1) { | |
e6c5bc73 JM |
3451 | cfqq->pid = current->pid; |
3452 | cfq_clear_cfqq_coop(cfqq); | |
ae54abed | 3453 | cfq_clear_cfqq_split_coop(cfqq); |
e6c5bc73 JM |
3454 | return cfqq; |
3455 | } | |
3456 | ||
3457 | cic_set_cfqq(cic, NULL, 1); | |
d02a2c07 SL |
3458 | |
3459 | cfq_put_cooperator(cfqq); | |
3460 | ||
e6c5bc73 JM |
3461 | cfq_put_queue(cfqq); |
3462 | return NULL; | |
3463 | } | |
1da177e4 | 3464 | /* |
22e2c507 | 3465 | * Allocate cfq data structures associated with this request. |
1da177e4 | 3466 | */ |
22e2c507 | 3467 | static int |
165125e1 | 3468 | cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask) |
1da177e4 LT |
3469 | { |
3470 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
f1f8cc94 | 3471 | struct cfq_io_cq *cic = icq_to_cic(rq->elv.icq); |
1da177e4 | 3472 | const int rw = rq_data_dir(rq); |
a6151c3a | 3473 | const bool is_sync = rq_is_sync(rq); |
22e2c507 | 3474 | struct cfq_queue *cfqq; |
d705ae6b | 3475 | unsigned int changed; |
1da177e4 LT |
3476 | |
3477 | might_sleep_if(gfp_mask & __GFP_WAIT); | |
3478 | ||
216284c3 | 3479 | spin_lock_irq(q->queue_lock); |
f1f8cc94 TH |
3480 | |
3481 | /* handle changed notifications */ | |
d705ae6b TH |
3482 | changed = icq_get_changed(&cic->icq); |
3483 | if (unlikely(changed & ICQ_IOPRIO_CHANGED)) | |
3484 | changed_ioprio(cic); | |
f1f8cc94 | 3485 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
d705ae6b TH |
3486 | if (unlikely(changed & ICQ_CGROUP_CHANGED)) |
3487 | changed_cgroup(cic); | |
f1f8cc94 | 3488 | #endif |
22e2c507 | 3489 | |
e6c5bc73 | 3490 | new_queue: |
91fac317 | 3491 | cfqq = cic_to_cfqq(cic, is_sync); |
32f2e807 | 3492 | if (!cfqq || cfqq == &cfqd->oom_cfqq) { |
c5869807 | 3493 | cfqq = cfq_get_queue(cfqd, is_sync, cic->icq.ioc, gfp_mask); |
91fac317 | 3494 | cic_set_cfqq(cic, cfqq, is_sync); |
df5fe3e8 | 3495 | } else { |
e6c5bc73 JM |
3496 | /* |
3497 | * If the queue was seeky for too long, break it apart. | |
3498 | */ | |
ae54abed | 3499 | if (cfq_cfqq_coop(cfqq) && cfq_cfqq_split_coop(cfqq)) { |
e6c5bc73 JM |
3500 | cfq_log_cfqq(cfqd, cfqq, "breaking apart cfqq"); |
3501 | cfqq = split_cfqq(cic, cfqq); | |
3502 | if (!cfqq) | |
3503 | goto new_queue; | |
3504 | } | |
3505 | ||
df5fe3e8 JM |
3506 | /* |
3507 | * Check to see if this queue is scheduled to merge with | |
3508 | * another, closely cooperating queue. The merging of | |
3509 | * queues happens here as it must be done in process context. | |
3510 | * The reference on new_cfqq was taken in merge_cfqqs. | |
3511 | */ | |
3512 | if (cfqq->new_cfqq) | |
3513 | cfqq = cfq_merge_cfqqs(cfqd, cic, cfqq); | |
91fac317 | 3514 | } |
1da177e4 LT |
3515 | |
3516 | cfqq->allocated[rw]++; | |
1da177e4 | 3517 | |
6fae9c25 | 3518 | cfqq->ref++; |
a612fddf TH |
3519 | rq->elv.priv[0] = cfqq; |
3520 | rq->elv.priv[1] = cfq_ref_get_cfqg(cfqq->cfqg); | |
216284c3 | 3521 | spin_unlock_irq(q->queue_lock); |
5e705374 | 3522 | return 0; |
1da177e4 LT |
3523 | } |
3524 | ||
65f27f38 | 3525 | static void cfq_kick_queue(struct work_struct *work) |
22e2c507 | 3526 | { |
65f27f38 | 3527 | struct cfq_data *cfqd = |
23e018a1 | 3528 | container_of(work, struct cfq_data, unplug_work); |
165125e1 | 3529 | struct request_queue *q = cfqd->queue; |
22e2c507 | 3530 | |
40bb54d1 | 3531 | spin_lock_irq(q->queue_lock); |
24ecfbe2 | 3532 | __blk_run_queue(cfqd->queue); |
40bb54d1 | 3533 | spin_unlock_irq(q->queue_lock); |
22e2c507 JA |
3534 | } |
3535 | ||
3536 | /* | |
3537 | * Timer running if the active_queue is currently idling inside its time slice | |
3538 | */ | |
3539 | static void cfq_idle_slice_timer(unsigned long data) | |
3540 | { | |
3541 | struct cfq_data *cfqd = (struct cfq_data *) data; | |
3542 | struct cfq_queue *cfqq; | |
3543 | unsigned long flags; | |
3c6bd2f8 | 3544 | int timed_out = 1; |
22e2c507 | 3545 | |
7b679138 JA |
3546 | cfq_log(cfqd, "idle timer fired"); |
3547 | ||
22e2c507 JA |
3548 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); |
3549 | ||
fe094d98 JA |
3550 | cfqq = cfqd->active_queue; |
3551 | if (cfqq) { | |
3c6bd2f8 JA |
3552 | timed_out = 0; |
3553 | ||
b029195d JA |
3554 | /* |
3555 | * We saw a request before the queue expired, let it through | |
3556 | */ | |
3557 | if (cfq_cfqq_must_dispatch(cfqq)) | |
3558 | goto out_kick; | |
3559 | ||
22e2c507 JA |
3560 | /* |
3561 | * expired | |
3562 | */ | |
44f7c160 | 3563 | if (cfq_slice_used(cfqq)) |
22e2c507 JA |
3564 | goto expire; |
3565 | ||
3566 | /* | |
3567 | * only expire and reinvoke request handler, if there are | |
3568 | * other queues with pending requests | |
3569 | */ | |
caaa5f9f | 3570 | if (!cfqd->busy_queues) |
22e2c507 | 3571 | goto out_cont; |
22e2c507 JA |
3572 | |
3573 | /* | |
3574 | * not expired and it has a request pending, let it dispatch | |
3575 | */ | |
75e50984 | 3576 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
22e2c507 | 3577 | goto out_kick; |
76280aff CZ |
3578 | |
3579 | /* | |
3580 | * Queue depth flag is reset only when the idle didn't succeed | |
3581 | */ | |
3582 | cfq_clear_cfqq_deep(cfqq); | |
22e2c507 JA |
3583 | } |
3584 | expire: | |
e5ff082e | 3585 | cfq_slice_expired(cfqd, timed_out); |
22e2c507 | 3586 | out_kick: |
23e018a1 | 3587 | cfq_schedule_dispatch(cfqd); |
22e2c507 JA |
3588 | out_cont: |
3589 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
3590 | } | |
3591 | ||
3b18152c JA |
3592 | static void cfq_shutdown_timer_wq(struct cfq_data *cfqd) |
3593 | { | |
3594 | del_timer_sync(&cfqd->idle_slice_timer); | |
23e018a1 | 3595 | cancel_work_sync(&cfqd->unplug_work); |
3b18152c | 3596 | } |
22e2c507 | 3597 | |
c2dea2d1 VT |
3598 | static void cfq_put_async_queues(struct cfq_data *cfqd) |
3599 | { | |
3600 | int i; | |
3601 | ||
3602 | for (i = 0; i < IOPRIO_BE_NR; i++) { | |
3603 | if (cfqd->async_cfqq[0][i]) | |
3604 | cfq_put_queue(cfqd->async_cfqq[0][i]); | |
3605 | if (cfqd->async_cfqq[1][i]) | |
3606 | cfq_put_queue(cfqd->async_cfqq[1][i]); | |
c2dea2d1 | 3607 | } |
2389d1ef ON |
3608 | |
3609 | if (cfqd->async_idle_cfqq) | |
3610 | cfq_put_queue(cfqd->async_idle_cfqq); | |
c2dea2d1 VT |
3611 | } |
3612 | ||
b374d18a | 3613 | static void cfq_exit_queue(struct elevator_queue *e) |
1da177e4 | 3614 | { |
22e2c507 | 3615 | struct cfq_data *cfqd = e->elevator_data; |
165125e1 | 3616 | struct request_queue *q = cfqd->queue; |
56edf7d7 | 3617 | bool wait = false; |
22e2c507 | 3618 | |
3b18152c | 3619 | cfq_shutdown_timer_wq(cfqd); |
e2d74ac0 | 3620 | |
d9ff4187 | 3621 | spin_lock_irq(q->queue_lock); |
e2d74ac0 | 3622 | |
d9ff4187 | 3623 | if (cfqd->active_queue) |
e5ff082e | 3624 | __cfq_slice_expired(cfqd, cfqd->active_queue, 0); |
e2d74ac0 | 3625 | |
c2dea2d1 | 3626 | cfq_put_async_queues(cfqd); |
b1c35769 | 3627 | cfq_release_cfq_groups(cfqd); |
56edf7d7 VG |
3628 | |
3629 | /* | |
3630 | * If there are groups which we could not unlink from blkcg list, | |
3631 | * wait for a rcu period for them to be freed. | |
3632 | */ | |
3633 | if (cfqd->nr_blkcg_linked_grps) | |
3634 | wait = true; | |
15c31be4 | 3635 | |
d9ff4187 | 3636 | spin_unlock_irq(q->queue_lock); |
a90d742e AV |
3637 | |
3638 | cfq_shutdown_timer_wq(cfqd); | |
3639 | ||
56edf7d7 VG |
3640 | /* |
3641 | * Wait for cfqg->blkg->key accessors to exit their grace periods. | |
3642 | * Do this wait only if there are other unlinked groups out | |
3643 | * there. This can happen if cgroup deletion path claimed the | |
3644 | * responsibility of cleaning up a group before queue cleanup code | |
3645 | * get to the group. | |
3646 | * | |
3647 | * Do not call synchronize_rcu() unconditionally as there are drivers | |
3648 | * which create/delete request queue hundreds of times during scan/boot | |
3649 | * and synchronize_rcu() can take significant time and slow down boot. | |
3650 | */ | |
3651 | if (wait) | |
3652 | synchronize_rcu(); | |
2abae55f VG |
3653 | |
3654 | #ifdef CONFIG_CFQ_GROUP_IOSCHED | |
3655 | /* Free up per cpu stats for root group */ | |
3656 | free_percpu(cfqd->root_group.blkg.stats_cpu); | |
3657 | #endif | |
56edf7d7 | 3658 | kfree(cfqd); |
1da177e4 LT |
3659 | } |
3660 | ||
165125e1 | 3661 | static void *cfq_init_queue(struct request_queue *q) |
1da177e4 LT |
3662 | { |
3663 | struct cfq_data *cfqd; | |
718eee05 | 3664 | int i, j; |
cdb16e8f | 3665 | struct cfq_group *cfqg; |
615f0259 | 3666 | struct cfq_rb_root *st; |
1da177e4 | 3667 | |
94f6030c | 3668 | cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL | __GFP_ZERO, q->node); |
a73f730d | 3669 | if (!cfqd) |
bc1c1169 | 3670 | return NULL; |
80b15c73 | 3671 | |
1fa8f6d6 VG |
3672 | /* Init root service tree */ |
3673 | cfqd->grp_service_tree = CFQ_RB_ROOT; | |
3674 | ||
cdb16e8f VG |
3675 | /* Init root group */ |
3676 | cfqg = &cfqd->root_group; | |
615f0259 VG |
3677 | for_each_cfqg_st(cfqg, i, j, st) |
3678 | *st = CFQ_RB_ROOT; | |
1fa8f6d6 | 3679 | RB_CLEAR_NODE(&cfqg->rb_node); |
26a2ac00 | 3680 | |
25bc6b07 VG |
3681 | /* Give preference to root group over other groups */ |
3682 | cfqg->weight = 2*BLKIO_WEIGHT_DEFAULT; | |
3683 | ||
25fb5169 | 3684 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
b1c35769 | 3685 | /* |
56edf7d7 VG |
3686 | * Set root group reference to 2. One reference will be dropped when |
3687 | * all groups on cfqd->cfqg_list are being deleted during queue exit. | |
3688 | * Other reference will remain there as we don't want to delete this | |
3689 | * group as it is statically allocated and gets destroyed when | |
3690 | * throtl_data goes away. | |
b1c35769 | 3691 | */ |
56edf7d7 | 3692 | cfqg->ref = 2; |
5624a4e4 VG |
3693 | |
3694 | if (blkio_alloc_blkg_stats(&cfqg->blkg)) { | |
3695 | kfree(cfqg); | |
3696 | kfree(cfqd); | |
3697 | return NULL; | |
3698 | } | |
3699 | ||
dcf097b2 | 3700 | rcu_read_lock(); |
5624a4e4 | 3701 | |
e98ef89b VG |
3702 | cfq_blkiocg_add_blkio_group(&blkio_root_cgroup, &cfqg->blkg, |
3703 | (void *)cfqd, 0); | |
dcf097b2 | 3704 | rcu_read_unlock(); |
56edf7d7 VG |
3705 | cfqd->nr_blkcg_linked_grps++; |
3706 | ||
3707 | /* Add group on cfqd->cfqg_list */ | |
3708 | hlist_add_head(&cfqg->cfqd_node, &cfqd->cfqg_list); | |
25fb5169 | 3709 | #endif |
26a2ac00 JA |
3710 | /* |
3711 | * Not strictly needed (since RB_ROOT just clears the node and we | |
3712 | * zeroed cfqd on alloc), but better be safe in case someone decides | |
3713 | * to add magic to the rb code | |
3714 | */ | |
3715 | for (i = 0; i < CFQ_PRIO_LISTS; i++) | |
3716 | cfqd->prio_trees[i] = RB_ROOT; | |
3717 | ||
6118b70b JA |
3718 | /* |
3719 | * Our fallback cfqq if cfq_find_alloc_queue() runs into OOM issues. | |
3720 | * Grab a permanent reference to it, so that the normal code flow | |
3721 | * will not attempt to free it. | |
3722 | */ | |
3723 | cfq_init_cfqq(cfqd, &cfqd->oom_cfqq, 1, 0); | |
30d7b944 | 3724 | cfqd->oom_cfqq.ref++; |
cdb16e8f | 3725 | cfq_link_cfqq_cfqg(&cfqd->oom_cfqq, &cfqd->root_group); |
6118b70b | 3726 | |
1da177e4 | 3727 | cfqd->queue = q; |
1da177e4 | 3728 | |
22e2c507 JA |
3729 | init_timer(&cfqd->idle_slice_timer); |
3730 | cfqd->idle_slice_timer.function = cfq_idle_slice_timer; | |
3731 | cfqd->idle_slice_timer.data = (unsigned long) cfqd; | |
3732 | ||
23e018a1 | 3733 | INIT_WORK(&cfqd->unplug_work, cfq_kick_queue); |
22e2c507 | 3734 | |
1da177e4 | 3735 | cfqd->cfq_quantum = cfq_quantum; |
22e2c507 JA |
3736 | cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; |
3737 | cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; | |
1da177e4 LT |
3738 | cfqd->cfq_back_max = cfq_back_max; |
3739 | cfqd->cfq_back_penalty = cfq_back_penalty; | |
22e2c507 JA |
3740 | cfqd->cfq_slice[0] = cfq_slice_async; |
3741 | cfqd->cfq_slice[1] = cfq_slice_sync; | |
5bf14c07 | 3742 | cfqd->cfq_target_latency = cfq_target_latency; |
22e2c507 JA |
3743 | cfqd->cfq_slice_async_rq = cfq_slice_async_rq; |
3744 | cfqd->cfq_slice_idle = cfq_slice_idle; | |
80bdf0c7 | 3745 | cfqd->cfq_group_idle = cfq_group_idle; |
963b72fc | 3746 | cfqd->cfq_latency = 1; |
e459dd08 | 3747 | cfqd->hw_tag = -1; |
edc71131 CZ |
3748 | /* |
3749 | * we optimistically start assuming sync ops weren't delayed in last | |
3750 | * second, in order to have larger depth for async operations. | |
3751 | */ | |
573412b2 | 3752 | cfqd->last_delayed_sync = jiffies - HZ; |
bc1c1169 | 3753 | return cfqd; |
1da177e4 LT |
3754 | } |
3755 | ||
1da177e4 LT |
3756 | /* |
3757 | * sysfs parts below --> | |
3758 | */ | |
1da177e4 LT |
3759 | static ssize_t |
3760 | cfq_var_show(unsigned int var, char *page) | |
3761 | { | |
3762 | return sprintf(page, "%d\n", var); | |
3763 | } | |
3764 | ||
3765 | static ssize_t | |
3766 | cfq_var_store(unsigned int *var, const char *page, size_t count) | |
3767 | { | |
3768 | char *p = (char *) page; | |
3769 | ||
3770 | *var = simple_strtoul(p, &p, 10); | |
3771 | return count; | |
3772 | } | |
3773 | ||
1da177e4 | 3774 | #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ |
b374d18a | 3775 | static ssize_t __FUNC(struct elevator_queue *e, char *page) \ |
1da177e4 | 3776 | { \ |
3d1ab40f | 3777 | struct cfq_data *cfqd = e->elevator_data; \ |
1da177e4 LT |
3778 | unsigned int __data = __VAR; \ |
3779 | if (__CONV) \ | |
3780 | __data = jiffies_to_msecs(__data); \ | |
3781 | return cfq_var_show(__data, (page)); \ | |
3782 | } | |
3783 | SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); | |
22e2c507 JA |
3784 | SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1); |
3785 | SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1); | |
e572ec7e AV |
3786 | SHOW_FUNCTION(cfq_back_seek_max_show, cfqd->cfq_back_max, 0); |
3787 | SHOW_FUNCTION(cfq_back_seek_penalty_show, cfqd->cfq_back_penalty, 0); | |
22e2c507 | 3788 | SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1); |
80bdf0c7 | 3789 | SHOW_FUNCTION(cfq_group_idle_show, cfqd->cfq_group_idle, 1); |
22e2c507 JA |
3790 | SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1); |
3791 | SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1); | |
3792 | SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0); | |
963b72fc | 3793 | SHOW_FUNCTION(cfq_low_latency_show, cfqd->cfq_latency, 0); |
5bf14c07 | 3794 | SHOW_FUNCTION(cfq_target_latency_show, cfqd->cfq_target_latency, 1); |
1da177e4 LT |
3795 | #undef SHOW_FUNCTION |
3796 | ||
3797 | #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ | |
b374d18a | 3798 | static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \ |
1da177e4 | 3799 | { \ |
3d1ab40f | 3800 | struct cfq_data *cfqd = e->elevator_data; \ |
1da177e4 LT |
3801 | unsigned int __data; \ |
3802 | int ret = cfq_var_store(&__data, (page), count); \ | |
3803 | if (__data < (MIN)) \ | |
3804 | __data = (MIN); \ | |
3805 | else if (__data > (MAX)) \ | |
3806 | __data = (MAX); \ | |
3807 | if (__CONV) \ | |
3808 | *(__PTR) = msecs_to_jiffies(__data); \ | |
3809 | else \ | |
3810 | *(__PTR) = __data; \ | |
3811 | return ret; \ | |
3812 | } | |
3813 | STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); | |
fe094d98 JA |
3814 | STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, |
3815 | UINT_MAX, 1); | |
3816 | STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, | |
3817 | UINT_MAX, 1); | |
e572ec7e | 3818 | STORE_FUNCTION(cfq_back_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); |
fe094d98 JA |
3819 | STORE_FUNCTION(cfq_back_seek_penalty_store, &cfqd->cfq_back_penalty, 1, |
3820 | UINT_MAX, 0); | |
22e2c507 | 3821 | STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1); |
80bdf0c7 | 3822 | STORE_FUNCTION(cfq_group_idle_store, &cfqd->cfq_group_idle, 0, UINT_MAX, 1); |
22e2c507 JA |
3823 | STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1); |
3824 | STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1); | |
fe094d98 JA |
3825 | STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, |
3826 | UINT_MAX, 0); | |
963b72fc | 3827 | STORE_FUNCTION(cfq_low_latency_store, &cfqd->cfq_latency, 0, 1, 0); |
5bf14c07 | 3828 | STORE_FUNCTION(cfq_target_latency_store, &cfqd->cfq_target_latency, 1, UINT_MAX, 1); |
1da177e4 LT |
3829 | #undef STORE_FUNCTION |
3830 | ||
e572ec7e AV |
3831 | #define CFQ_ATTR(name) \ |
3832 | __ATTR(name, S_IRUGO|S_IWUSR, cfq_##name##_show, cfq_##name##_store) | |
3833 | ||
3834 | static struct elv_fs_entry cfq_attrs[] = { | |
3835 | CFQ_ATTR(quantum), | |
e572ec7e AV |
3836 | CFQ_ATTR(fifo_expire_sync), |
3837 | CFQ_ATTR(fifo_expire_async), | |
3838 | CFQ_ATTR(back_seek_max), | |
3839 | CFQ_ATTR(back_seek_penalty), | |
3840 | CFQ_ATTR(slice_sync), | |
3841 | CFQ_ATTR(slice_async), | |
3842 | CFQ_ATTR(slice_async_rq), | |
3843 | CFQ_ATTR(slice_idle), | |
80bdf0c7 | 3844 | CFQ_ATTR(group_idle), |
963b72fc | 3845 | CFQ_ATTR(low_latency), |
5bf14c07 | 3846 | CFQ_ATTR(target_latency), |
e572ec7e | 3847 | __ATTR_NULL |
1da177e4 LT |
3848 | }; |
3849 | ||
1da177e4 LT |
3850 | static struct elevator_type iosched_cfq = { |
3851 | .ops = { | |
3852 | .elevator_merge_fn = cfq_merge, | |
3853 | .elevator_merged_fn = cfq_merged_request, | |
3854 | .elevator_merge_req_fn = cfq_merged_requests, | |
da775265 | 3855 | .elevator_allow_merge_fn = cfq_allow_merge, |
812d4026 | 3856 | .elevator_bio_merged_fn = cfq_bio_merged, |
b4878f24 | 3857 | .elevator_dispatch_fn = cfq_dispatch_requests, |
1da177e4 | 3858 | .elevator_add_req_fn = cfq_insert_request, |
b4878f24 | 3859 | .elevator_activate_req_fn = cfq_activate_request, |
1da177e4 | 3860 | .elevator_deactivate_req_fn = cfq_deactivate_request, |
1da177e4 | 3861 | .elevator_completed_req_fn = cfq_completed_request, |
21183b07 JA |
3862 | .elevator_former_req_fn = elv_rb_former_request, |
3863 | .elevator_latter_req_fn = elv_rb_latter_request, | |
9b84cacd | 3864 | .elevator_init_icq_fn = cfq_init_icq, |
7e5a8794 | 3865 | .elevator_exit_icq_fn = cfq_exit_icq, |
1da177e4 LT |
3866 | .elevator_set_req_fn = cfq_set_request, |
3867 | .elevator_put_req_fn = cfq_put_request, | |
3868 | .elevator_may_queue_fn = cfq_may_queue, | |
3869 | .elevator_init_fn = cfq_init_queue, | |
3870 | .elevator_exit_fn = cfq_exit_queue, | |
3871 | }, | |
3d3c2379 TH |
3872 | .icq_size = sizeof(struct cfq_io_cq), |
3873 | .icq_align = __alignof__(struct cfq_io_cq), | |
3d1ab40f | 3874 | .elevator_attrs = cfq_attrs, |
3d3c2379 | 3875 | .elevator_name = "cfq", |
1da177e4 LT |
3876 | .elevator_owner = THIS_MODULE, |
3877 | }; | |
3878 | ||
3e252066 VG |
3879 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
3880 | static struct blkio_policy_type blkio_policy_cfq = { | |
3881 | .ops = { | |
3882 | .blkio_unlink_group_fn = cfq_unlink_blkio_group, | |
3883 | .blkio_update_group_weight_fn = cfq_update_blkio_group_weight, | |
3884 | }, | |
062a644d | 3885 | .plid = BLKIO_POLICY_PROP, |
3e252066 VG |
3886 | }; |
3887 | #else | |
3888 | static struct blkio_policy_type blkio_policy_cfq; | |
3889 | #endif | |
3890 | ||
1da177e4 LT |
3891 | static int __init cfq_init(void) |
3892 | { | |
3d3c2379 TH |
3893 | int ret; |
3894 | ||
22e2c507 JA |
3895 | /* |
3896 | * could be 0 on HZ < 1000 setups | |
3897 | */ | |
3898 | if (!cfq_slice_async) | |
3899 | cfq_slice_async = 1; | |
3900 | if (!cfq_slice_idle) | |
3901 | cfq_slice_idle = 1; | |
3902 | ||
80bdf0c7 VG |
3903 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
3904 | if (!cfq_group_idle) | |
3905 | cfq_group_idle = 1; | |
3906 | #else | |
3907 | cfq_group_idle = 0; | |
3908 | #endif | |
3d3c2379 TH |
3909 | cfq_pool = KMEM_CACHE(cfq_queue, 0); |
3910 | if (!cfq_pool) | |
1da177e4 LT |
3911 | return -ENOMEM; |
3912 | ||
3d3c2379 TH |
3913 | ret = elv_register(&iosched_cfq); |
3914 | if (ret) { | |
3915 | kmem_cache_destroy(cfq_pool); | |
3916 | return ret; | |
3917 | } | |
3d3c2379 | 3918 | |
3e252066 | 3919 | blkio_policy_register(&blkio_policy_cfq); |
1da177e4 | 3920 | |
2fdd82bd | 3921 | return 0; |
1da177e4 LT |
3922 | } |
3923 | ||
3924 | static void __exit cfq_exit(void) | |
3925 | { | |
3e252066 | 3926 | blkio_policy_unregister(&blkio_policy_cfq); |
1da177e4 | 3927 | elv_unregister(&iosched_cfq); |
3d3c2379 | 3928 | kmem_cache_destroy(cfq_pool); |
1da177e4 LT |
3929 | } |
3930 | ||
3931 | module_init(cfq_init); | |
3932 | module_exit(cfq_exit); | |
3933 | ||
3934 | MODULE_AUTHOR("Jens Axboe"); | |
3935 | MODULE_LICENSE("GPL"); | |
3936 | MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler"); |