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 | |
fe094d98 | 57 | #define RQ_CIC(rq) \ |
c186794d MS |
58 | ((struct cfq_io_context *) (rq)->elevator_private[0]) |
59 | #define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elevator_private[1]) | |
60 | #define RQ_CFQG(rq) (struct cfq_group *) ((rq)->elevator_private[2]) | |
1da177e4 | 61 | |
e18b890b CL |
62 | static struct kmem_cache *cfq_pool; |
63 | static struct kmem_cache *cfq_ioc_pool; | |
1da177e4 | 64 | |
245b2e70 | 65 | static DEFINE_PER_CPU(unsigned long, cfq_ioc_count); |
334e94de | 66 | static struct completion *ioc_gone; |
9a11b4ed | 67 | static DEFINE_SPINLOCK(ioc_gone_lock); |
334e94de | 68 | |
22e2c507 JA |
69 | #define CFQ_PRIO_LISTS IOPRIO_BE_NR |
70 | #define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE) | |
22e2c507 JA |
71 | #define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT) |
72 | ||
206dc69b | 73 | #define sample_valid(samples) ((samples) > 80) |
1fa8f6d6 | 74 | #define rb_entry_cfqg(node) rb_entry((node), struct cfq_group, rb_node) |
206dc69b | 75 | |
cc09e299 JA |
76 | /* |
77 | * Most of our rbtree usage is for sorting with min extraction, so | |
78 | * if we cache the leftmost node we don't have to walk down the tree | |
79 | * to find it. Idea borrowed from Ingo Molnars CFS scheduler. We should | |
80 | * move this into the elevator for the rq sorting as well. | |
81 | */ | |
82 | struct cfq_rb_root { | |
83 | struct rb_root rb; | |
84 | struct rb_node *left; | |
aa6f6a3d | 85 | unsigned count; |
73e9ffdd | 86 | unsigned total_weight; |
1fa8f6d6 | 87 | u64 min_vdisktime; |
f5f2b6ce | 88 | struct cfq_ttime ttime; |
cc09e299 | 89 | }; |
f5f2b6ce SL |
90 | #define CFQ_RB_ROOT (struct cfq_rb_root) { .rb = RB_ROOT, \ |
91 | .ttime = {.last_end_request = jiffies,},} | |
cc09e299 | 92 | |
6118b70b JA |
93 | /* |
94 | * Per process-grouping structure | |
95 | */ | |
96 | struct cfq_queue { | |
97 | /* reference count */ | |
30d7b944 | 98 | int ref; |
6118b70b JA |
99 | /* various state flags, see below */ |
100 | unsigned int flags; | |
101 | /* parent cfq_data */ | |
102 | struct cfq_data *cfqd; | |
103 | /* service_tree member */ | |
104 | struct rb_node rb_node; | |
105 | /* service_tree key */ | |
106 | unsigned long rb_key; | |
107 | /* prio tree member */ | |
108 | struct rb_node p_node; | |
109 | /* prio tree root we belong to, if any */ | |
110 | struct rb_root *p_root; | |
111 | /* sorted list of pending requests */ | |
112 | struct rb_root sort_list; | |
113 | /* if fifo isn't expired, next request to serve */ | |
114 | struct request *next_rq; | |
115 | /* requests queued in sort_list */ | |
116 | int queued[2]; | |
117 | /* currently allocated requests */ | |
118 | int allocated[2]; | |
119 | /* fifo list of requests in sort_list */ | |
120 | struct list_head fifo; | |
121 | ||
dae739eb VG |
122 | /* time when queue got scheduled in to dispatch first request. */ |
123 | unsigned long dispatch_start; | |
f75edf2d | 124 | unsigned int allocated_slice; |
c4081ba5 | 125 | unsigned int slice_dispatch; |
dae739eb VG |
126 | /* time when first request from queue completed and slice started. */ |
127 | unsigned long slice_start; | |
6118b70b JA |
128 | unsigned long slice_end; |
129 | long slice_resid; | |
6118b70b | 130 | |
65299a3b CH |
131 | /* pending priority requests */ |
132 | int prio_pending; | |
6118b70b JA |
133 | /* number of requests that are on the dispatch list or inside driver */ |
134 | int dispatched; | |
135 | ||
136 | /* io prio of this group */ | |
137 | unsigned short ioprio, org_ioprio; | |
4aede84b | 138 | unsigned short ioprio_class; |
6118b70b | 139 | |
c4081ba5 RK |
140 | pid_t pid; |
141 | ||
3dde36dd | 142 | u32 seek_history; |
b2c18e1e JM |
143 | sector_t last_request_pos; |
144 | ||
aa6f6a3d | 145 | struct cfq_rb_root *service_tree; |
df5fe3e8 | 146 | struct cfq_queue *new_cfqq; |
cdb16e8f | 147 | struct cfq_group *cfqg; |
c4e7893e VG |
148 | /* Number of sectors dispatched from queue in single dispatch round */ |
149 | unsigned long nr_sectors; | |
6118b70b JA |
150 | }; |
151 | ||
c0324a02 | 152 | /* |
718eee05 | 153 | * First index in the service_trees. |
c0324a02 CZ |
154 | * IDLE is handled separately, so it has negative index |
155 | */ | |
156 | enum wl_prio_t { | |
c0324a02 | 157 | BE_WORKLOAD = 0, |
615f0259 VG |
158 | RT_WORKLOAD = 1, |
159 | IDLE_WORKLOAD = 2, | |
b4627321 | 160 | CFQ_PRIO_NR, |
c0324a02 CZ |
161 | }; |
162 | ||
718eee05 CZ |
163 | /* |
164 | * Second index in the service_trees. | |
165 | */ | |
166 | enum wl_type_t { | |
167 | ASYNC_WORKLOAD = 0, | |
168 | SYNC_NOIDLE_WORKLOAD = 1, | |
169 | SYNC_WORKLOAD = 2 | |
170 | }; | |
171 | ||
cdb16e8f VG |
172 | /* This is per cgroup per device grouping structure */ |
173 | struct cfq_group { | |
1fa8f6d6 VG |
174 | /* group service_tree member */ |
175 | struct rb_node rb_node; | |
176 | ||
177 | /* group service_tree key */ | |
178 | u64 vdisktime; | |
25bc6b07 | 179 | unsigned int weight; |
8184f93e JT |
180 | unsigned int new_weight; |
181 | bool needs_update; | |
1fa8f6d6 VG |
182 | |
183 | /* number of cfqq currently on this group */ | |
184 | int nr_cfqq; | |
185 | ||
cdb16e8f | 186 | /* |
4495a7d4 | 187 | * Per group busy queues average. Useful for workload slice calc. We |
b4627321 VG |
188 | * create the array for each prio class but at run time it is used |
189 | * only for RT and BE class and slot for IDLE class remains unused. | |
190 | * This is primarily done to avoid confusion and a gcc warning. | |
191 | */ | |
192 | unsigned int busy_queues_avg[CFQ_PRIO_NR]; | |
193 | /* | |
194 | * rr lists of queues with requests. We maintain service trees for | |
195 | * RT and BE classes. These trees are subdivided in subclasses | |
196 | * of SYNC, SYNC_NOIDLE and ASYNC based on workload type. For IDLE | |
197 | * class there is no subclassification and all the cfq queues go on | |
198 | * a single tree service_tree_idle. | |
cdb16e8f VG |
199 | * Counts are embedded in the cfq_rb_root |
200 | */ | |
201 | struct cfq_rb_root service_trees[2][3]; | |
202 | struct cfq_rb_root service_tree_idle; | |
dae739eb VG |
203 | |
204 | unsigned long saved_workload_slice; | |
205 | enum wl_type_t saved_workload; | |
206 | enum wl_prio_t saved_serving_prio; | |
25fb5169 VG |
207 | struct blkio_group blkg; |
208 | #ifdef CONFIG_CFQ_GROUP_IOSCHED | |
209 | struct hlist_node cfqd_node; | |
329a6781 | 210 | int ref; |
25fb5169 | 211 | #endif |
80bdf0c7 VG |
212 | /* number of requests that are on the dispatch list or inside driver */ |
213 | int dispatched; | |
7700fc4f | 214 | struct cfq_ttime ttime; |
cdb16e8f | 215 | }; |
718eee05 | 216 | |
22e2c507 JA |
217 | /* |
218 | * Per block device queue structure | |
219 | */ | |
1da177e4 | 220 | struct cfq_data { |
165125e1 | 221 | struct request_queue *queue; |
1fa8f6d6 VG |
222 | /* Root service tree for cfq_groups */ |
223 | struct cfq_rb_root grp_service_tree; | |
cdb16e8f | 224 | struct cfq_group root_group; |
22e2c507 | 225 | |
c0324a02 CZ |
226 | /* |
227 | * The priority currently being served | |
22e2c507 | 228 | */ |
c0324a02 | 229 | enum wl_prio_t serving_prio; |
718eee05 CZ |
230 | enum wl_type_t serving_type; |
231 | unsigned long workload_expires; | |
cdb16e8f | 232 | struct cfq_group *serving_group; |
a36e71f9 JA |
233 | |
234 | /* | |
235 | * Each priority tree is sorted by next_request position. These | |
236 | * trees are used when determining if two or more queues are | |
237 | * interleaving requests (see cfq_close_cooperator). | |
238 | */ | |
239 | struct rb_root prio_trees[CFQ_PRIO_LISTS]; | |
240 | ||
22e2c507 | 241 | unsigned int busy_queues; |
ef8a41df | 242 | unsigned int busy_sync_queues; |
22e2c507 | 243 | |
53c583d2 CZ |
244 | int rq_in_driver; |
245 | int rq_in_flight[2]; | |
45333d5a AC |
246 | |
247 | /* | |
248 | * queue-depth detection | |
249 | */ | |
250 | int rq_queued; | |
25776e35 | 251 | int hw_tag; |
e459dd08 CZ |
252 | /* |
253 | * hw_tag can be | |
254 | * -1 => indeterminate, (cfq will behave as if NCQ is present, to allow better detection) | |
255 | * 1 => NCQ is present (hw_tag_est_depth is the estimated max depth) | |
256 | * 0 => no NCQ | |
257 | */ | |
258 | int hw_tag_est_depth; | |
259 | unsigned int hw_tag_samples; | |
1da177e4 | 260 | |
22e2c507 JA |
261 | /* |
262 | * idle window management | |
263 | */ | |
264 | struct timer_list idle_slice_timer; | |
23e018a1 | 265 | struct work_struct unplug_work; |
1da177e4 | 266 | |
22e2c507 JA |
267 | struct cfq_queue *active_queue; |
268 | struct cfq_io_context *active_cic; | |
22e2c507 | 269 | |
c2dea2d1 VT |
270 | /* |
271 | * async queue for each priority case | |
272 | */ | |
273 | struct cfq_queue *async_cfqq[2][IOPRIO_BE_NR]; | |
274 | struct cfq_queue *async_idle_cfqq; | |
15c31be4 | 275 | |
6d048f53 | 276 | sector_t last_position; |
1da177e4 | 277 | |
1da177e4 LT |
278 | /* |
279 | * tunables, see top of file | |
280 | */ | |
281 | unsigned int cfq_quantum; | |
22e2c507 | 282 | unsigned int cfq_fifo_expire[2]; |
1da177e4 LT |
283 | unsigned int cfq_back_penalty; |
284 | unsigned int cfq_back_max; | |
22e2c507 JA |
285 | unsigned int cfq_slice[2]; |
286 | unsigned int cfq_slice_async_rq; | |
287 | unsigned int cfq_slice_idle; | |
80bdf0c7 | 288 | unsigned int cfq_group_idle; |
963b72fc | 289 | unsigned int cfq_latency; |
d9ff4187 AV |
290 | |
291 | struct list_head cic_list; | |
1da177e4 | 292 | |
6118b70b JA |
293 | /* |
294 | * Fallback dummy cfqq for extreme OOM conditions | |
295 | */ | |
296 | struct cfq_queue oom_cfqq; | |
365722bb | 297 | |
573412b2 | 298 | unsigned long last_delayed_sync; |
25fb5169 VG |
299 | |
300 | /* List of cfq groups being managed on this device*/ | |
301 | struct hlist_head cfqg_list; | |
56edf7d7 VG |
302 | |
303 | /* Number of groups which are on blkcg->blkg_list */ | |
304 | unsigned int nr_blkcg_linked_grps; | |
1da177e4 LT |
305 | }; |
306 | ||
25fb5169 VG |
307 | static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd); |
308 | ||
cdb16e8f VG |
309 | static struct cfq_rb_root *service_tree_for(struct cfq_group *cfqg, |
310 | enum wl_prio_t prio, | |
65b32a57 | 311 | enum wl_type_t type) |
c0324a02 | 312 | { |
1fa8f6d6 VG |
313 | if (!cfqg) |
314 | return NULL; | |
315 | ||
c0324a02 | 316 | if (prio == IDLE_WORKLOAD) |
cdb16e8f | 317 | return &cfqg->service_tree_idle; |
c0324a02 | 318 | |
cdb16e8f | 319 | return &cfqg->service_trees[prio][type]; |
c0324a02 CZ |
320 | } |
321 | ||
3b18152c | 322 | enum cfqq_state_flags { |
b0b8d749 JA |
323 | CFQ_CFQQ_FLAG_on_rr = 0, /* on round-robin busy list */ |
324 | CFQ_CFQQ_FLAG_wait_request, /* waiting for a request */ | |
b029195d | 325 | CFQ_CFQQ_FLAG_must_dispatch, /* must be allowed a dispatch */ |
b0b8d749 | 326 | CFQ_CFQQ_FLAG_must_alloc_slice, /* per-slice must_alloc flag */ |
b0b8d749 JA |
327 | CFQ_CFQQ_FLAG_fifo_expire, /* FIFO checked in this slice */ |
328 | CFQ_CFQQ_FLAG_idle_window, /* slice idling enabled */ | |
329 | CFQ_CFQQ_FLAG_prio_changed, /* task priority has changed */ | |
44f7c160 | 330 | CFQ_CFQQ_FLAG_slice_new, /* no requests dispatched in slice */ |
91fac317 | 331 | CFQ_CFQQ_FLAG_sync, /* synchronous queue */ |
b3b6d040 | 332 | CFQ_CFQQ_FLAG_coop, /* cfqq is shared */ |
ae54abed | 333 | CFQ_CFQQ_FLAG_split_coop, /* shared cfqq will be splitted */ |
76280aff | 334 | CFQ_CFQQ_FLAG_deep, /* sync cfqq experienced large depth */ |
f75edf2d | 335 | CFQ_CFQQ_FLAG_wait_busy, /* Waiting for next request */ |
3b18152c JA |
336 | }; |
337 | ||
338 | #define CFQ_CFQQ_FNS(name) \ | |
339 | static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \ | |
340 | { \ | |
fe094d98 | 341 | (cfqq)->flags |= (1 << CFQ_CFQQ_FLAG_##name); \ |
3b18152c JA |
342 | } \ |
343 | static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \ | |
344 | { \ | |
fe094d98 | 345 | (cfqq)->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \ |
3b18152c JA |
346 | } \ |
347 | static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \ | |
348 | { \ | |
fe094d98 | 349 | return ((cfqq)->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \ |
3b18152c JA |
350 | } |
351 | ||
352 | CFQ_CFQQ_FNS(on_rr); | |
353 | CFQ_CFQQ_FNS(wait_request); | |
b029195d | 354 | CFQ_CFQQ_FNS(must_dispatch); |
3b18152c | 355 | CFQ_CFQQ_FNS(must_alloc_slice); |
3b18152c JA |
356 | CFQ_CFQQ_FNS(fifo_expire); |
357 | CFQ_CFQQ_FNS(idle_window); | |
358 | CFQ_CFQQ_FNS(prio_changed); | |
44f7c160 | 359 | CFQ_CFQQ_FNS(slice_new); |
91fac317 | 360 | CFQ_CFQQ_FNS(sync); |
a36e71f9 | 361 | CFQ_CFQQ_FNS(coop); |
ae54abed | 362 | CFQ_CFQQ_FNS(split_coop); |
76280aff | 363 | CFQ_CFQQ_FNS(deep); |
f75edf2d | 364 | CFQ_CFQQ_FNS(wait_busy); |
3b18152c JA |
365 | #undef CFQ_CFQQ_FNS |
366 | ||
afc24d49 | 367 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
2868ef7b VG |
368 | #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \ |
369 | blk_add_trace_msg((cfqd)->queue, "cfq%d%c %s " fmt, (cfqq)->pid, \ | |
370 | cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \ | |
4495a7d4 | 371 | blkg_path(&(cfqq)->cfqg->blkg), ##args) |
2868ef7b VG |
372 | |
373 | #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) \ | |
374 | blk_add_trace_msg((cfqd)->queue, "%s " fmt, \ | |
4495a7d4 | 375 | blkg_path(&(cfqg)->blkg), ##args) \ |
2868ef7b VG |
376 | |
377 | #else | |
7b679138 JA |
378 | #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \ |
379 | blk_add_trace_msg((cfqd)->queue, "cfq%d " fmt, (cfqq)->pid, ##args) | |
4495a7d4 | 380 | #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) do {} while (0) |
2868ef7b | 381 | #endif |
7b679138 JA |
382 | #define cfq_log(cfqd, fmt, args...) \ |
383 | blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args) | |
384 | ||
615f0259 VG |
385 | /* Traverses through cfq group service trees */ |
386 | #define for_each_cfqg_st(cfqg, i, j, st) \ | |
387 | for (i = 0; i <= IDLE_WORKLOAD; i++) \ | |
388 | for (j = 0, st = i < IDLE_WORKLOAD ? &cfqg->service_trees[i][j]\ | |
389 | : &cfqg->service_tree_idle; \ | |
390 | (i < IDLE_WORKLOAD && j <= SYNC_WORKLOAD) || \ | |
391 | (i == IDLE_WORKLOAD && j == 0); \ | |
392 | j++, st = i < IDLE_WORKLOAD ? \ | |
393 | &cfqg->service_trees[i][j]: NULL) \ | |
394 | ||
f5f2b6ce SL |
395 | static inline bool cfq_io_thinktime_big(struct cfq_data *cfqd, |
396 | struct cfq_ttime *ttime, bool group_idle) | |
397 | { | |
398 | unsigned long slice; | |
399 | if (!sample_valid(ttime->ttime_samples)) | |
400 | return false; | |
401 | if (group_idle) | |
402 | slice = cfqd->cfq_group_idle; | |
403 | else | |
404 | slice = cfqd->cfq_slice_idle; | |
405 | return ttime->ttime_mean > slice; | |
406 | } | |
615f0259 | 407 | |
02b35081 VG |
408 | static inline bool iops_mode(struct cfq_data *cfqd) |
409 | { | |
410 | /* | |
411 | * If we are not idling on queues and it is a NCQ drive, parallel | |
412 | * execution of requests is on and measuring time is not possible | |
413 | * in most of the cases until and unless we drive shallower queue | |
414 | * depths and that becomes a performance bottleneck. In such cases | |
415 | * switch to start providing fairness in terms of number of IOs. | |
416 | */ | |
417 | if (!cfqd->cfq_slice_idle && cfqd->hw_tag) | |
418 | return true; | |
419 | else | |
420 | return false; | |
421 | } | |
422 | ||
c0324a02 CZ |
423 | static inline enum wl_prio_t cfqq_prio(struct cfq_queue *cfqq) |
424 | { | |
425 | if (cfq_class_idle(cfqq)) | |
426 | return IDLE_WORKLOAD; | |
427 | if (cfq_class_rt(cfqq)) | |
428 | return RT_WORKLOAD; | |
429 | return BE_WORKLOAD; | |
430 | } | |
431 | ||
718eee05 CZ |
432 | |
433 | static enum wl_type_t cfqq_type(struct cfq_queue *cfqq) | |
434 | { | |
435 | if (!cfq_cfqq_sync(cfqq)) | |
436 | return ASYNC_WORKLOAD; | |
437 | if (!cfq_cfqq_idle_window(cfqq)) | |
438 | return SYNC_NOIDLE_WORKLOAD; | |
439 | return SYNC_WORKLOAD; | |
440 | } | |
441 | ||
58ff82f3 VG |
442 | static inline int cfq_group_busy_queues_wl(enum wl_prio_t wl, |
443 | struct cfq_data *cfqd, | |
444 | struct cfq_group *cfqg) | |
c0324a02 CZ |
445 | { |
446 | if (wl == IDLE_WORKLOAD) | |
cdb16e8f | 447 | return cfqg->service_tree_idle.count; |
c0324a02 | 448 | |
cdb16e8f VG |
449 | return cfqg->service_trees[wl][ASYNC_WORKLOAD].count |
450 | + cfqg->service_trees[wl][SYNC_NOIDLE_WORKLOAD].count | |
451 | + cfqg->service_trees[wl][SYNC_WORKLOAD].count; | |
c0324a02 CZ |
452 | } |
453 | ||
f26bd1f0 VG |
454 | static inline int cfqg_busy_async_queues(struct cfq_data *cfqd, |
455 | struct cfq_group *cfqg) | |
456 | { | |
457 | return cfqg->service_trees[RT_WORKLOAD][ASYNC_WORKLOAD].count | |
458 | + cfqg->service_trees[BE_WORKLOAD][ASYNC_WORKLOAD].count; | |
459 | } | |
460 | ||
165125e1 | 461 | static void cfq_dispatch_insert(struct request_queue *, struct request *); |
a6151c3a | 462 | static struct cfq_queue *cfq_get_queue(struct cfq_data *, bool, |
fd0928df | 463 | struct io_context *, gfp_t); |
4ac845a2 | 464 | static struct cfq_io_context *cfq_cic_lookup(struct cfq_data *, |
91fac317 VT |
465 | struct io_context *); |
466 | ||
467 | static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_context *cic, | |
a6151c3a | 468 | bool is_sync) |
91fac317 | 469 | { |
a6151c3a | 470 | return cic->cfqq[is_sync]; |
91fac317 VT |
471 | } |
472 | ||
473 | static inline void cic_set_cfqq(struct cfq_io_context *cic, | |
a6151c3a | 474 | struct cfq_queue *cfqq, bool is_sync) |
91fac317 | 475 | { |
a6151c3a | 476 | cic->cfqq[is_sync] = cfqq; |
91fac317 VT |
477 | } |
478 | ||
bca4b914 | 479 | #define CIC_DEAD_KEY 1ul |
80b15c73 | 480 | #define CIC_DEAD_INDEX_SHIFT 1 |
bca4b914 KK |
481 | |
482 | static inline void *cfqd_dead_key(struct cfq_data *cfqd) | |
483 | { | |
a73f730d | 484 | return (void *)(cfqd->queue->id << CIC_DEAD_INDEX_SHIFT | CIC_DEAD_KEY); |
bca4b914 KK |
485 | } |
486 | ||
487 | static inline struct cfq_data *cic_to_cfqd(struct cfq_io_context *cic) | |
488 | { | |
489 | struct cfq_data *cfqd = cic->key; | |
490 | ||
491 | if (unlikely((unsigned long) cfqd & CIC_DEAD_KEY)) | |
492 | return NULL; | |
493 | ||
494 | return cfqd; | |
495 | } | |
496 | ||
91fac317 VT |
497 | /* |
498 | * We regard a request as SYNC, if it's either a read or has the SYNC bit | |
499 | * set (in which case it could also be direct WRITE). | |
500 | */ | |
a6151c3a | 501 | static inline bool cfq_bio_sync(struct bio *bio) |
91fac317 | 502 | { |
7b6d91da | 503 | return bio_data_dir(bio) == READ || (bio->bi_rw & REQ_SYNC); |
91fac317 | 504 | } |
1da177e4 | 505 | |
99f95e52 AM |
506 | /* |
507 | * scheduler run of queue, if there are requests pending and no one in the | |
508 | * driver that will restart queueing | |
509 | */ | |
23e018a1 | 510 | static inline void cfq_schedule_dispatch(struct cfq_data *cfqd) |
99f95e52 | 511 | { |
7b679138 JA |
512 | if (cfqd->busy_queues) { |
513 | cfq_log(cfqd, "schedule dispatch"); | |
23e018a1 | 514 | kblockd_schedule_work(cfqd->queue, &cfqd->unplug_work); |
7b679138 | 515 | } |
99f95e52 AM |
516 | } |
517 | ||
44f7c160 JA |
518 | /* |
519 | * Scale schedule slice based on io priority. Use the sync time slice only | |
520 | * if a queue is marked sync and has sync io queued. A sync queue with async | |
521 | * io only, should not get full sync slice length. | |
522 | */ | |
a6151c3a | 523 | static inline int cfq_prio_slice(struct cfq_data *cfqd, bool sync, |
d9e7620e | 524 | unsigned short prio) |
44f7c160 | 525 | { |
d9e7620e | 526 | const int base_slice = cfqd->cfq_slice[sync]; |
44f7c160 | 527 | |
d9e7620e JA |
528 | WARN_ON(prio >= IOPRIO_BE_NR); |
529 | ||
530 | return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - prio)); | |
531 | } | |
44f7c160 | 532 | |
d9e7620e JA |
533 | static inline int |
534 | cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
535 | { | |
536 | return cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio); | |
44f7c160 JA |
537 | } |
538 | ||
25bc6b07 VG |
539 | static inline u64 cfq_scale_slice(unsigned long delta, struct cfq_group *cfqg) |
540 | { | |
541 | u64 d = delta << CFQ_SERVICE_SHIFT; | |
542 | ||
543 | d = d * BLKIO_WEIGHT_DEFAULT; | |
544 | do_div(d, cfqg->weight); | |
545 | return d; | |
546 | } | |
547 | ||
548 | static inline u64 max_vdisktime(u64 min_vdisktime, u64 vdisktime) | |
549 | { | |
550 | s64 delta = (s64)(vdisktime - min_vdisktime); | |
551 | if (delta > 0) | |
552 | min_vdisktime = vdisktime; | |
553 | ||
554 | return min_vdisktime; | |
555 | } | |
556 | ||
557 | static inline u64 min_vdisktime(u64 min_vdisktime, u64 vdisktime) | |
558 | { | |
559 | s64 delta = (s64)(vdisktime - min_vdisktime); | |
560 | if (delta < 0) | |
561 | min_vdisktime = vdisktime; | |
562 | ||
563 | return min_vdisktime; | |
564 | } | |
565 | ||
566 | static void update_min_vdisktime(struct cfq_rb_root *st) | |
567 | { | |
25bc6b07 VG |
568 | struct cfq_group *cfqg; |
569 | ||
25bc6b07 VG |
570 | if (st->left) { |
571 | cfqg = rb_entry_cfqg(st->left); | |
a6032710 GJ |
572 | st->min_vdisktime = max_vdisktime(st->min_vdisktime, |
573 | cfqg->vdisktime); | |
25bc6b07 | 574 | } |
25bc6b07 VG |
575 | } |
576 | ||
5db5d642 CZ |
577 | /* |
578 | * get averaged number of queues of RT/BE priority. | |
579 | * average is updated, with a formula that gives more weight to higher numbers, | |
580 | * to quickly follows sudden increases and decrease slowly | |
581 | */ | |
582 | ||
58ff82f3 VG |
583 | static inline unsigned cfq_group_get_avg_queues(struct cfq_data *cfqd, |
584 | struct cfq_group *cfqg, bool rt) | |
5869619c | 585 | { |
5db5d642 CZ |
586 | unsigned min_q, max_q; |
587 | unsigned mult = cfq_hist_divisor - 1; | |
588 | unsigned round = cfq_hist_divisor / 2; | |
58ff82f3 | 589 | unsigned busy = cfq_group_busy_queues_wl(rt, cfqd, cfqg); |
5db5d642 | 590 | |
58ff82f3 VG |
591 | min_q = min(cfqg->busy_queues_avg[rt], busy); |
592 | max_q = max(cfqg->busy_queues_avg[rt], busy); | |
593 | cfqg->busy_queues_avg[rt] = (mult * max_q + min_q + round) / | |
5db5d642 | 594 | cfq_hist_divisor; |
58ff82f3 VG |
595 | return cfqg->busy_queues_avg[rt]; |
596 | } | |
597 | ||
598 | static inline unsigned | |
599 | cfq_group_slice(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
600 | { | |
601 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
602 | ||
603 | return cfq_target_latency * cfqg->weight / st->total_weight; | |
5db5d642 CZ |
604 | } |
605 | ||
c553f8e3 | 606 | static inline unsigned |
ba5bd520 | 607 | cfq_scaled_cfqq_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
44f7c160 | 608 | { |
5db5d642 CZ |
609 | unsigned slice = cfq_prio_to_slice(cfqd, cfqq); |
610 | if (cfqd->cfq_latency) { | |
58ff82f3 VG |
611 | /* |
612 | * interested queues (we consider only the ones with the same | |
613 | * priority class in the cfq group) | |
614 | */ | |
615 | unsigned iq = cfq_group_get_avg_queues(cfqd, cfqq->cfqg, | |
616 | cfq_class_rt(cfqq)); | |
5db5d642 CZ |
617 | unsigned sync_slice = cfqd->cfq_slice[1]; |
618 | unsigned expect_latency = sync_slice * iq; | |
58ff82f3 VG |
619 | unsigned group_slice = cfq_group_slice(cfqd, cfqq->cfqg); |
620 | ||
621 | if (expect_latency > group_slice) { | |
5db5d642 CZ |
622 | unsigned base_low_slice = 2 * cfqd->cfq_slice_idle; |
623 | /* scale low_slice according to IO priority | |
624 | * and sync vs async */ | |
625 | unsigned low_slice = | |
626 | min(slice, base_low_slice * slice / sync_slice); | |
627 | /* the adapted slice value is scaled to fit all iqs | |
628 | * into the target latency */ | |
58ff82f3 | 629 | slice = max(slice * group_slice / expect_latency, |
5db5d642 CZ |
630 | low_slice); |
631 | } | |
632 | } | |
c553f8e3 SL |
633 | return slice; |
634 | } | |
635 | ||
636 | static inline void | |
637 | cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
638 | { | |
ba5bd520 | 639 | unsigned slice = cfq_scaled_cfqq_slice(cfqd, cfqq); |
c553f8e3 | 640 | |
dae739eb | 641 | cfqq->slice_start = jiffies; |
5db5d642 | 642 | cfqq->slice_end = jiffies + slice; |
f75edf2d | 643 | cfqq->allocated_slice = slice; |
7b679138 | 644 | cfq_log_cfqq(cfqd, cfqq, "set_slice=%lu", cfqq->slice_end - jiffies); |
44f7c160 JA |
645 | } |
646 | ||
647 | /* | |
648 | * We need to wrap this check in cfq_cfqq_slice_new(), since ->slice_end | |
649 | * isn't valid until the first request from the dispatch is activated | |
650 | * and the slice time set. | |
651 | */ | |
a6151c3a | 652 | static inline bool cfq_slice_used(struct cfq_queue *cfqq) |
44f7c160 JA |
653 | { |
654 | if (cfq_cfqq_slice_new(cfqq)) | |
c1e44756 | 655 | return false; |
44f7c160 | 656 | if (time_before(jiffies, cfqq->slice_end)) |
c1e44756 | 657 | return false; |
44f7c160 | 658 | |
c1e44756 | 659 | return true; |
44f7c160 JA |
660 | } |
661 | ||
1da177e4 | 662 | /* |
5e705374 | 663 | * Lifted from AS - choose which of rq1 and rq2 that is best served now. |
1da177e4 | 664 | * We choose the request that is closest to the head right now. Distance |
e8a99053 | 665 | * behind the head is penalized and only allowed to a certain extent. |
1da177e4 | 666 | */ |
5e705374 | 667 | static struct request * |
cf7c25cf | 668 | cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2, sector_t last) |
1da177e4 | 669 | { |
cf7c25cf | 670 | sector_t s1, s2, d1 = 0, d2 = 0; |
1da177e4 | 671 | unsigned long back_max; |
e8a99053 AM |
672 | #define CFQ_RQ1_WRAP 0x01 /* request 1 wraps */ |
673 | #define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */ | |
674 | unsigned wrap = 0; /* bit mask: requests behind the disk head? */ | |
1da177e4 | 675 | |
5e705374 JA |
676 | if (rq1 == NULL || rq1 == rq2) |
677 | return rq2; | |
678 | if (rq2 == NULL) | |
679 | return rq1; | |
9c2c38a1 | 680 | |
229836bd NK |
681 | if (rq_is_sync(rq1) != rq_is_sync(rq2)) |
682 | return rq_is_sync(rq1) ? rq1 : rq2; | |
683 | ||
65299a3b CH |
684 | if ((rq1->cmd_flags ^ rq2->cmd_flags) & REQ_PRIO) |
685 | return rq1->cmd_flags & REQ_PRIO ? rq1 : rq2; | |
b53d1ed7 | 686 | |
83096ebf TH |
687 | s1 = blk_rq_pos(rq1); |
688 | s2 = blk_rq_pos(rq2); | |
1da177e4 | 689 | |
1da177e4 LT |
690 | /* |
691 | * by definition, 1KiB is 2 sectors | |
692 | */ | |
693 | back_max = cfqd->cfq_back_max * 2; | |
694 | ||
695 | /* | |
696 | * Strict one way elevator _except_ in the case where we allow | |
697 | * short backward seeks which are biased as twice the cost of a | |
698 | * similar forward seek. | |
699 | */ | |
700 | if (s1 >= last) | |
701 | d1 = s1 - last; | |
702 | else if (s1 + back_max >= last) | |
703 | d1 = (last - s1) * cfqd->cfq_back_penalty; | |
704 | else | |
e8a99053 | 705 | wrap |= CFQ_RQ1_WRAP; |
1da177e4 LT |
706 | |
707 | if (s2 >= last) | |
708 | d2 = s2 - last; | |
709 | else if (s2 + back_max >= last) | |
710 | d2 = (last - s2) * cfqd->cfq_back_penalty; | |
711 | else | |
e8a99053 | 712 | wrap |= CFQ_RQ2_WRAP; |
1da177e4 LT |
713 | |
714 | /* Found required data */ | |
e8a99053 AM |
715 | |
716 | /* | |
717 | * By doing switch() on the bit mask "wrap" we avoid having to | |
718 | * check two variables for all permutations: --> faster! | |
719 | */ | |
720 | switch (wrap) { | |
5e705374 | 721 | case 0: /* common case for CFQ: rq1 and rq2 not wrapped */ |
e8a99053 | 722 | if (d1 < d2) |
5e705374 | 723 | return rq1; |
e8a99053 | 724 | else if (d2 < d1) |
5e705374 | 725 | return rq2; |
e8a99053 AM |
726 | else { |
727 | if (s1 >= s2) | |
5e705374 | 728 | return rq1; |
e8a99053 | 729 | else |
5e705374 | 730 | return rq2; |
e8a99053 | 731 | } |
1da177e4 | 732 | |
e8a99053 | 733 | case CFQ_RQ2_WRAP: |
5e705374 | 734 | return rq1; |
e8a99053 | 735 | case CFQ_RQ1_WRAP: |
5e705374 JA |
736 | return rq2; |
737 | case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both rqs wrapped */ | |
e8a99053 AM |
738 | default: |
739 | /* | |
740 | * Since both rqs are wrapped, | |
741 | * start with the one that's further behind head | |
742 | * (--> only *one* back seek required), | |
743 | * since back seek takes more time than forward. | |
744 | */ | |
745 | if (s1 <= s2) | |
5e705374 | 746 | return rq1; |
1da177e4 | 747 | else |
5e705374 | 748 | return rq2; |
1da177e4 LT |
749 | } |
750 | } | |
751 | ||
498d3aa2 JA |
752 | /* |
753 | * The below is leftmost cache rbtree addon | |
754 | */ | |
0871714e | 755 | static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root) |
cc09e299 | 756 | { |
615f0259 VG |
757 | /* Service tree is empty */ |
758 | if (!root->count) | |
759 | return NULL; | |
760 | ||
cc09e299 JA |
761 | if (!root->left) |
762 | root->left = rb_first(&root->rb); | |
763 | ||
0871714e JA |
764 | if (root->left) |
765 | return rb_entry(root->left, struct cfq_queue, rb_node); | |
766 | ||
767 | return NULL; | |
cc09e299 JA |
768 | } |
769 | ||
1fa8f6d6 VG |
770 | static struct cfq_group *cfq_rb_first_group(struct cfq_rb_root *root) |
771 | { | |
772 | if (!root->left) | |
773 | root->left = rb_first(&root->rb); | |
774 | ||
775 | if (root->left) | |
776 | return rb_entry_cfqg(root->left); | |
777 | ||
778 | return NULL; | |
779 | } | |
780 | ||
a36e71f9 JA |
781 | static void rb_erase_init(struct rb_node *n, struct rb_root *root) |
782 | { | |
783 | rb_erase(n, root); | |
784 | RB_CLEAR_NODE(n); | |
785 | } | |
786 | ||
cc09e299 JA |
787 | static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root) |
788 | { | |
789 | if (root->left == n) | |
790 | root->left = NULL; | |
a36e71f9 | 791 | rb_erase_init(n, &root->rb); |
aa6f6a3d | 792 | --root->count; |
cc09e299 JA |
793 | } |
794 | ||
1da177e4 LT |
795 | /* |
796 | * would be nice to take fifo expire time into account as well | |
797 | */ | |
5e705374 JA |
798 | static struct request * |
799 | cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
800 | struct request *last) | |
1da177e4 | 801 | { |
21183b07 JA |
802 | struct rb_node *rbnext = rb_next(&last->rb_node); |
803 | struct rb_node *rbprev = rb_prev(&last->rb_node); | |
5e705374 | 804 | struct request *next = NULL, *prev = NULL; |
1da177e4 | 805 | |
21183b07 | 806 | BUG_ON(RB_EMPTY_NODE(&last->rb_node)); |
1da177e4 LT |
807 | |
808 | if (rbprev) | |
5e705374 | 809 | prev = rb_entry_rq(rbprev); |
1da177e4 | 810 | |
21183b07 | 811 | if (rbnext) |
5e705374 | 812 | next = rb_entry_rq(rbnext); |
21183b07 JA |
813 | else { |
814 | rbnext = rb_first(&cfqq->sort_list); | |
815 | if (rbnext && rbnext != &last->rb_node) | |
5e705374 | 816 | next = rb_entry_rq(rbnext); |
21183b07 | 817 | } |
1da177e4 | 818 | |
cf7c25cf | 819 | return cfq_choose_req(cfqd, next, prev, blk_rq_pos(last)); |
1da177e4 LT |
820 | } |
821 | ||
d9e7620e JA |
822 | static unsigned long cfq_slice_offset(struct cfq_data *cfqd, |
823 | struct cfq_queue *cfqq) | |
1da177e4 | 824 | { |
d9e7620e JA |
825 | /* |
826 | * just an approximation, should be ok. | |
827 | */ | |
cdb16e8f | 828 | return (cfqq->cfqg->nr_cfqq - 1) * (cfq_prio_slice(cfqd, 1, 0) - |
464191c6 | 829 | cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio)); |
d9e7620e JA |
830 | } |
831 | ||
1fa8f6d6 VG |
832 | static inline s64 |
833 | cfqg_key(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
834 | { | |
835 | return cfqg->vdisktime - st->min_vdisktime; | |
836 | } | |
837 | ||
838 | static void | |
839 | __cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
840 | { | |
841 | struct rb_node **node = &st->rb.rb_node; | |
842 | struct rb_node *parent = NULL; | |
843 | struct cfq_group *__cfqg; | |
844 | s64 key = cfqg_key(st, cfqg); | |
845 | int left = 1; | |
846 | ||
847 | while (*node != NULL) { | |
848 | parent = *node; | |
849 | __cfqg = rb_entry_cfqg(parent); | |
850 | ||
851 | if (key < cfqg_key(st, __cfqg)) | |
852 | node = &parent->rb_left; | |
853 | else { | |
854 | node = &parent->rb_right; | |
855 | left = 0; | |
856 | } | |
857 | } | |
858 | ||
859 | if (left) | |
860 | st->left = &cfqg->rb_node; | |
861 | ||
862 | rb_link_node(&cfqg->rb_node, parent, node); | |
863 | rb_insert_color(&cfqg->rb_node, &st->rb); | |
864 | } | |
865 | ||
866 | static void | |
8184f93e JT |
867 | cfq_update_group_weight(struct cfq_group *cfqg) |
868 | { | |
869 | BUG_ON(!RB_EMPTY_NODE(&cfqg->rb_node)); | |
870 | if (cfqg->needs_update) { | |
871 | cfqg->weight = cfqg->new_weight; | |
872 | cfqg->needs_update = false; | |
873 | } | |
874 | } | |
875 | ||
876 | static void | |
877 | cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
878 | { | |
879 | BUG_ON(!RB_EMPTY_NODE(&cfqg->rb_node)); | |
880 | ||
881 | cfq_update_group_weight(cfqg); | |
882 | __cfq_group_service_tree_add(st, cfqg); | |
883 | st->total_weight += cfqg->weight; | |
884 | } | |
885 | ||
886 | static void | |
887 | cfq_group_notify_queue_add(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
1fa8f6d6 VG |
888 | { |
889 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
890 | struct cfq_group *__cfqg; | |
891 | struct rb_node *n; | |
892 | ||
893 | cfqg->nr_cfqq++; | |
760701bf | 894 | if (!RB_EMPTY_NODE(&cfqg->rb_node)) |
1fa8f6d6 VG |
895 | return; |
896 | ||
897 | /* | |
898 | * Currently put the group at the end. Later implement something | |
899 | * so that groups get lesser vtime based on their weights, so that | |
25985edc | 900 | * if group does not loose all if it was not continuously backlogged. |
1fa8f6d6 VG |
901 | */ |
902 | n = rb_last(&st->rb); | |
903 | if (n) { | |
904 | __cfqg = rb_entry_cfqg(n); | |
905 | cfqg->vdisktime = __cfqg->vdisktime + CFQ_IDLE_DELAY; | |
906 | } else | |
907 | cfqg->vdisktime = st->min_vdisktime; | |
8184f93e JT |
908 | cfq_group_service_tree_add(st, cfqg); |
909 | } | |
1fa8f6d6 | 910 | |
8184f93e JT |
911 | static void |
912 | cfq_group_service_tree_del(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
913 | { | |
914 | st->total_weight -= cfqg->weight; | |
915 | if (!RB_EMPTY_NODE(&cfqg->rb_node)) | |
916 | cfq_rb_erase(&cfqg->rb_node, st); | |
1fa8f6d6 VG |
917 | } |
918 | ||
919 | static void | |
8184f93e | 920 | cfq_group_notify_queue_del(struct cfq_data *cfqd, struct cfq_group *cfqg) |
1fa8f6d6 VG |
921 | { |
922 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
923 | ||
924 | BUG_ON(cfqg->nr_cfqq < 1); | |
925 | cfqg->nr_cfqq--; | |
25bc6b07 | 926 | |
1fa8f6d6 VG |
927 | /* If there are other cfq queues under this group, don't delete it */ |
928 | if (cfqg->nr_cfqq) | |
929 | return; | |
930 | ||
2868ef7b | 931 | cfq_log_cfqg(cfqd, cfqg, "del_from_rr group"); |
8184f93e | 932 | cfq_group_service_tree_del(st, cfqg); |
dae739eb | 933 | cfqg->saved_workload_slice = 0; |
e98ef89b | 934 | cfq_blkiocg_update_dequeue_stats(&cfqg->blkg, 1); |
dae739eb VG |
935 | } |
936 | ||
167400d3 JT |
937 | static inline unsigned int cfq_cfqq_slice_usage(struct cfq_queue *cfqq, |
938 | unsigned int *unaccounted_time) | |
dae739eb | 939 | { |
f75edf2d | 940 | unsigned int slice_used; |
dae739eb VG |
941 | |
942 | /* | |
943 | * Queue got expired before even a single request completed or | |
944 | * got expired immediately after first request completion. | |
945 | */ | |
946 | if (!cfqq->slice_start || cfqq->slice_start == jiffies) { | |
947 | /* | |
948 | * Also charge the seek time incurred to the group, otherwise | |
949 | * if there are mutiple queues in the group, each can dispatch | |
950 | * a single request on seeky media and cause lots of seek time | |
951 | * and group will never know it. | |
952 | */ | |
953 | slice_used = max_t(unsigned, (jiffies - cfqq->dispatch_start), | |
954 | 1); | |
955 | } else { | |
956 | slice_used = jiffies - cfqq->slice_start; | |
167400d3 JT |
957 | if (slice_used > cfqq->allocated_slice) { |
958 | *unaccounted_time = slice_used - cfqq->allocated_slice; | |
f75edf2d | 959 | slice_used = cfqq->allocated_slice; |
167400d3 JT |
960 | } |
961 | if (time_after(cfqq->slice_start, cfqq->dispatch_start)) | |
962 | *unaccounted_time += cfqq->slice_start - | |
963 | cfqq->dispatch_start; | |
dae739eb VG |
964 | } |
965 | ||
dae739eb VG |
966 | return slice_used; |
967 | } | |
968 | ||
969 | static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg, | |
e5ff082e | 970 | struct cfq_queue *cfqq) |
dae739eb VG |
971 | { |
972 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
167400d3 | 973 | unsigned int used_sl, charge, unaccounted_sl = 0; |
f26bd1f0 VG |
974 | int nr_sync = cfqg->nr_cfqq - cfqg_busy_async_queues(cfqd, cfqg) |
975 | - cfqg->service_tree_idle.count; | |
976 | ||
977 | BUG_ON(nr_sync < 0); | |
167400d3 | 978 | used_sl = charge = cfq_cfqq_slice_usage(cfqq, &unaccounted_sl); |
dae739eb | 979 | |
02b35081 VG |
980 | if (iops_mode(cfqd)) |
981 | charge = cfqq->slice_dispatch; | |
982 | else if (!cfq_cfqq_sync(cfqq) && !nr_sync) | |
983 | charge = cfqq->allocated_slice; | |
dae739eb VG |
984 | |
985 | /* Can't update vdisktime while group is on service tree */ | |
8184f93e | 986 | cfq_group_service_tree_del(st, cfqg); |
02b35081 | 987 | cfqg->vdisktime += cfq_scale_slice(charge, cfqg); |
8184f93e JT |
988 | /* If a new weight was requested, update now, off tree */ |
989 | cfq_group_service_tree_add(st, cfqg); | |
dae739eb VG |
990 | |
991 | /* This group is being expired. Save the context */ | |
992 | if (time_after(cfqd->workload_expires, jiffies)) { | |
993 | cfqg->saved_workload_slice = cfqd->workload_expires | |
994 | - jiffies; | |
995 | cfqg->saved_workload = cfqd->serving_type; | |
996 | cfqg->saved_serving_prio = cfqd->serving_prio; | |
997 | } else | |
998 | cfqg->saved_workload_slice = 0; | |
2868ef7b VG |
999 | |
1000 | cfq_log_cfqg(cfqd, cfqg, "served: vt=%llu min_vt=%llu", cfqg->vdisktime, | |
1001 | st->min_vdisktime); | |
fd16d263 JP |
1002 | cfq_log_cfqq(cfqq->cfqd, cfqq, |
1003 | "sl_used=%u disp=%u charge=%u iops=%u sect=%lu", | |
1004 | used_sl, cfqq->slice_dispatch, charge, | |
1005 | iops_mode(cfqd), cfqq->nr_sectors); | |
167400d3 JT |
1006 | cfq_blkiocg_update_timeslice_used(&cfqg->blkg, used_sl, |
1007 | unaccounted_sl); | |
e98ef89b | 1008 | cfq_blkiocg_set_start_empty_time(&cfqg->blkg); |
1fa8f6d6 VG |
1009 | } |
1010 | ||
25fb5169 VG |
1011 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
1012 | static inline struct cfq_group *cfqg_of_blkg(struct blkio_group *blkg) | |
1013 | { | |
1014 | if (blkg) | |
1015 | return container_of(blkg, struct cfq_group, blkg); | |
1016 | return NULL; | |
1017 | } | |
1018 | ||
8aea4545 PB |
1019 | static void cfq_update_blkio_group_weight(void *key, struct blkio_group *blkg, |
1020 | unsigned int weight) | |
f8d461d6 | 1021 | { |
8184f93e JT |
1022 | struct cfq_group *cfqg = cfqg_of_blkg(blkg); |
1023 | cfqg->new_weight = weight; | |
1024 | cfqg->needs_update = true; | |
f8d461d6 VG |
1025 | } |
1026 | ||
f469a7b4 VG |
1027 | static void cfq_init_add_cfqg_lists(struct cfq_data *cfqd, |
1028 | struct cfq_group *cfqg, struct blkio_cgroup *blkcg) | |
25fb5169 | 1029 | { |
22084190 VG |
1030 | struct backing_dev_info *bdi = &cfqd->queue->backing_dev_info; |
1031 | unsigned int major, minor; | |
25fb5169 | 1032 | |
f469a7b4 VG |
1033 | /* |
1034 | * Add group onto cgroup list. It might happen that bdi->dev is | |
1035 | * not initialized yet. Initialize this new group without major | |
1036 | * and minor info and this info will be filled in once a new thread | |
1037 | * comes for IO. | |
1038 | */ | |
1039 | if (bdi->dev) { | |
a74b2ada | 1040 | sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor); |
f469a7b4 VG |
1041 | cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg, |
1042 | (void *)cfqd, MKDEV(major, minor)); | |
1043 | } else | |
1044 | cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg, | |
1045 | (void *)cfqd, 0); | |
1046 | ||
1047 | cfqd->nr_blkcg_linked_grps++; | |
1048 | cfqg->weight = blkcg_get_weight(blkcg, cfqg->blkg.dev); | |
1049 | ||
1050 | /* Add group on cfqd list */ | |
1051 | hlist_add_head(&cfqg->cfqd_node, &cfqd->cfqg_list); | |
1052 | } | |
1053 | ||
1054 | /* | |
1055 | * Should be called from sleepable context. No request queue lock as per | |
1056 | * cpu stats are allocated dynamically and alloc_percpu needs to be called | |
1057 | * from sleepable context. | |
1058 | */ | |
1059 | static struct cfq_group * cfq_alloc_cfqg(struct cfq_data *cfqd) | |
1060 | { | |
1061 | struct cfq_group *cfqg = NULL; | |
5624a4e4 | 1062 | int i, j, ret; |
f469a7b4 | 1063 | struct cfq_rb_root *st; |
25fb5169 VG |
1064 | |
1065 | cfqg = kzalloc_node(sizeof(*cfqg), GFP_ATOMIC, cfqd->queue->node); | |
1066 | if (!cfqg) | |
f469a7b4 | 1067 | return NULL; |
25fb5169 | 1068 | |
25fb5169 VG |
1069 | for_each_cfqg_st(cfqg, i, j, st) |
1070 | *st = CFQ_RB_ROOT; | |
1071 | RB_CLEAR_NODE(&cfqg->rb_node); | |
1072 | ||
7700fc4f SL |
1073 | cfqg->ttime.last_end_request = jiffies; |
1074 | ||
b1c35769 VG |
1075 | /* |
1076 | * Take the initial reference that will be released on destroy | |
1077 | * This can be thought of a joint reference by cgroup and | |
1078 | * elevator which will be dropped by either elevator exit | |
1079 | * or cgroup deletion path depending on who is exiting first. | |
1080 | */ | |
329a6781 | 1081 | cfqg->ref = 1; |
5624a4e4 VG |
1082 | |
1083 | ret = blkio_alloc_blkg_stats(&cfqg->blkg); | |
1084 | if (ret) { | |
1085 | kfree(cfqg); | |
1086 | return NULL; | |
1087 | } | |
1088 | ||
f469a7b4 VG |
1089 | return cfqg; |
1090 | } | |
1091 | ||
1092 | static struct cfq_group * | |
1093 | cfq_find_cfqg(struct cfq_data *cfqd, struct blkio_cgroup *blkcg) | |
1094 | { | |
1095 | struct cfq_group *cfqg = NULL; | |
1096 | void *key = cfqd; | |
1097 | struct backing_dev_info *bdi = &cfqd->queue->backing_dev_info; | |
1098 | unsigned int major, minor; | |
b1c35769 | 1099 | |
180be2a0 | 1100 | /* |
f469a7b4 VG |
1101 | * This is the common case when there are no blkio cgroups. |
1102 | * Avoid lookup in this case | |
180be2a0 | 1103 | */ |
f469a7b4 VG |
1104 | if (blkcg == &blkio_root_cgroup) |
1105 | cfqg = &cfqd->root_group; | |
1106 | else | |
1107 | cfqg = cfqg_of_blkg(blkiocg_lookup_group(blkcg, key)); | |
25fb5169 | 1108 | |
f469a7b4 VG |
1109 | if (cfqg && !cfqg->blkg.dev && bdi->dev && dev_name(bdi->dev)) { |
1110 | sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor); | |
1111 | cfqg->blkg.dev = MKDEV(major, minor); | |
1112 | } | |
25fb5169 | 1113 | |
25fb5169 VG |
1114 | return cfqg; |
1115 | } | |
1116 | ||
1117 | /* | |
3e59cf9d VG |
1118 | * Search for the cfq group current task belongs to. request_queue lock must |
1119 | * be held. | |
25fb5169 | 1120 | */ |
3e59cf9d | 1121 | static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd) |
25fb5169 | 1122 | { |
70087dc3 | 1123 | struct blkio_cgroup *blkcg; |
f469a7b4 VG |
1124 | struct cfq_group *cfqg = NULL, *__cfqg = NULL; |
1125 | struct request_queue *q = cfqd->queue; | |
25fb5169 VG |
1126 | |
1127 | rcu_read_lock(); | |
70087dc3 | 1128 | blkcg = task_blkio_cgroup(current); |
f469a7b4 VG |
1129 | cfqg = cfq_find_cfqg(cfqd, blkcg); |
1130 | if (cfqg) { | |
1131 | rcu_read_unlock(); | |
1132 | return cfqg; | |
1133 | } | |
1134 | ||
1135 | /* | |
1136 | * Need to allocate a group. Allocation of group also needs allocation | |
1137 | * of per cpu stats which in-turn takes a mutex() and can block. Hence | |
1138 | * we need to drop rcu lock and queue_lock before we call alloc. | |
1139 | * | |
1140 | * Not taking any queue reference here and assuming that queue is | |
1141 | * around by the time we return. CFQ queue allocation code does | |
1142 | * the same. It might be racy though. | |
1143 | */ | |
1144 | ||
1145 | rcu_read_unlock(); | |
1146 | spin_unlock_irq(q->queue_lock); | |
1147 | ||
1148 | cfqg = cfq_alloc_cfqg(cfqd); | |
1149 | ||
1150 | spin_lock_irq(q->queue_lock); | |
1151 | ||
1152 | rcu_read_lock(); | |
1153 | blkcg = task_blkio_cgroup(current); | |
1154 | ||
1155 | /* | |
1156 | * If some other thread already allocated the group while we were | |
1157 | * not holding queue lock, free up the group | |
1158 | */ | |
1159 | __cfqg = cfq_find_cfqg(cfqd, blkcg); | |
1160 | ||
1161 | if (__cfqg) { | |
1162 | kfree(cfqg); | |
1163 | rcu_read_unlock(); | |
1164 | return __cfqg; | |
1165 | } | |
1166 | ||
3e59cf9d | 1167 | if (!cfqg) |
25fb5169 | 1168 | cfqg = &cfqd->root_group; |
f469a7b4 VG |
1169 | |
1170 | cfq_init_add_cfqg_lists(cfqd, cfqg, blkcg); | |
25fb5169 VG |
1171 | rcu_read_unlock(); |
1172 | return cfqg; | |
1173 | } | |
1174 | ||
7f1dc8a2 VG |
1175 | static inline struct cfq_group *cfq_ref_get_cfqg(struct cfq_group *cfqg) |
1176 | { | |
329a6781 | 1177 | cfqg->ref++; |
7f1dc8a2 VG |
1178 | return cfqg; |
1179 | } | |
1180 | ||
25fb5169 VG |
1181 | static void cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) |
1182 | { | |
1183 | /* Currently, all async queues are mapped to root group */ | |
1184 | if (!cfq_cfqq_sync(cfqq)) | |
1185 | cfqg = &cfqq->cfqd->root_group; | |
1186 | ||
1187 | cfqq->cfqg = cfqg; | |
b1c35769 | 1188 | /* cfqq reference on cfqg */ |
329a6781 | 1189 | cfqq->cfqg->ref++; |
b1c35769 VG |
1190 | } |
1191 | ||
1192 | static void cfq_put_cfqg(struct cfq_group *cfqg) | |
1193 | { | |
1194 | struct cfq_rb_root *st; | |
1195 | int i, j; | |
1196 | ||
329a6781 SL |
1197 | BUG_ON(cfqg->ref <= 0); |
1198 | cfqg->ref--; | |
1199 | if (cfqg->ref) | |
b1c35769 VG |
1200 | return; |
1201 | for_each_cfqg_st(cfqg, i, j, st) | |
b54ce60e | 1202 | BUG_ON(!RB_EMPTY_ROOT(&st->rb)); |
5624a4e4 | 1203 | free_percpu(cfqg->blkg.stats_cpu); |
b1c35769 VG |
1204 | kfree(cfqg); |
1205 | } | |
1206 | ||
1207 | static void cfq_destroy_cfqg(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
1208 | { | |
1209 | /* Something wrong if we are trying to remove same group twice */ | |
1210 | BUG_ON(hlist_unhashed(&cfqg->cfqd_node)); | |
1211 | ||
1212 | hlist_del_init(&cfqg->cfqd_node); | |
1213 | ||
a5395b83 VG |
1214 | BUG_ON(cfqd->nr_blkcg_linked_grps <= 0); |
1215 | cfqd->nr_blkcg_linked_grps--; | |
1216 | ||
b1c35769 VG |
1217 | /* |
1218 | * Put the reference taken at the time of creation so that when all | |
1219 | * queues are gone, group can be destroyed. | |
1220 | */ | |
1221 | cfq_put_cfqg(cfqg); | |
1222 | } | |
1223 | ||
1224 | static void cfq_release_cfq_groups(struct cfq_data *cfqd) | |
1225 | { | |
1226 | struct hlist_node *pos, *n; | |
1227 | struct cfq_group *cfqg; | |
1228 | ||
1229 | hlist_for_each_entry_safe(cfqg, pos, n, &cfqd->cfqg_list, cfqd_node) { | |
1230 | /* | |
1231 | * If cgroup removal path got to blk_group first and removed | |
1232 | * it from cgroup list, then it will take care of destroying | |
1233 | * cfqg also. | |
1234 | */ | |
e98ef89b | 1235 | if (!cfq_blkiocg_del_blkio_group(&cfqg->blkg)) |
b1c35769 VG |
1236 | cfq_destroy_cfqg(cfqd, cfqg); |
1237 | } | |
25fb5169 | 1238 | } |
b1c35769 VG |
1239 | |
1240 | /* | |
1241 | * Blk cgroup controller notification saying that blkio_group object is being | |
1242 | * delinked as associated cgroup object is going away. That also means that | |
1243 | * no new IO will come in this group. So get rid of this group as soon as | |
1244 | * any pending IO in the group is finished. | |
1245 | * | |
1246 | * This function is called under rcu_read_lock(). key is the rcu protected | |
1247 | * pointer. That means "key" is a valid cfq_data pointer as long as we are rcu | |
1248 | * read lock. | |
1249 | * | |
1250 | * "key" was fetched from blkio_group under blkio_cgroup->lock. That means | |
1251 | * it should not be NULL as even if elevator was exiting, cgroup deltion | |
1252 | * path got to it first. | |
1253 | */ | |
8aea4545 | 1254 | static void cfq_unlink_blkio_group(void *key, struct blkio_group *blkg) |
b1c35769 VG |
1255 | { |
1256 | unsigned long flags; | |
1257 | struct cfq_data *cfqd = key; | |
1258 | ||
1259 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
1260 | cfq_destroy_cfqg(cfqd, cfqg_of_blkg(blkg)); | |
1261 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
1262 | } | |
1263 | ||
25fb5169 | 1264 | #else /* GROUP_IOSCHED */ |
3e59cf9d | 1265 | static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd) |
25fb5169 VG |
1266 | { |
1267 | return &cfqd->root_group; | |
1268 | } | |
7f1dc8a2 VG |
1269 | |
1270 | static inline struct cfq_group *cfq_ref_get_cfqg(struct cfq_group *cfqg) | |
1271 | { | |
50eaeb32 | 1272 | return cfqg; |
7f1dc8a2 VG |
1273 | } |
1274 | ||
25fb5169 VG |
1275 | static inline void |
1276 | cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) { | |
1277 | cfqq->cfqg = cfqg; | |
1278 | } | |
1279 | ||
b1c35769 VG |
1280 | static void cfq_release_cfq_groups(struct cfq_data *cfqd) {} |
1281 | static inline void cfq_put_cfqg(struct cfq_group *cfqg) {} | |
1282 | ||
25fb5169 VG |
1283 | #endif /* GROUP_IOSCHED */ |
1284 | ||
498d3aa2 | 1285 | /* |
c0324a02 | 1286 | * The cfqd->service_trees holds all pending cfq_queue's that have |
498d3aa2 JA |
1287 | * requests waiting to be processed. It is sorted in the order that |
1288 | * we will service the queues. | |
1289 | */ | |
a36e71f9 | 1290 | static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
a6151c3a | 1291 | bool add_front) |
d9e7620e | 1292 | { |
0871714e JA |
1293 | struct rb_node **p, *parent; |
1294 | struct cfq_queue *__cfqq; | |
d9e7620e | 1295 | unsigned long rb_key; |
c0324a02 | 1296 | struct cfq_rb_root *service_tree; |
498d3aa2 | 1297 | int left; |
dae739eb | 1298 | int new_cfqq = 1; |
ae30c286 | 1299 | |
cdb16e8f | 1300 | service_tree = service_tree_for(cfqq->cfqg, cfqq_prio(cfqq), |
65b32a57 | 1301 | cfqq_type(cfqq)); |
0871714e JA |
1302 | if (cfq_class_idle(cfqq)) { |
1303 | rb_key = CFQ_IDLE_DELAY; | |
aa6f6a3d | 1304 | parent = rb_last(&service_tree->rb); |
0871714e JA |
1305 | if (parent && parent != &cfqq->rb_node) { |
1306 | __cfqq = rb_entry(parent, struct cfq_queue, rb_node); | |
1307 | rb_key += __cfqq->rb_key; | |
1308 | } else | |
1309 | rb_key += jiffies; | |
1310 | } else if (!add_front) { | |
b9c8946b JA |
1311 | /* |
1312 | * Get our rb key offset. Subtract any residual slice | |
1313 | * value carried from last service. A negative resid | |
1314 | * count indicates slice overrun, and this should position | |
1315 | * the next service time further away in the tree. | |
1316 | */ | |
edd75ffd | 1317 | rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies; |
b9c8946b | 1318 | rb_key -= cfqq->slice_resid; |
edd75ffd | 1319 | cfqq->slice_resid = 0; |
48e025e6 CZ |
1320 | } else { |
1321 | rb_key = -HZ; | |
aa6f6a3d | 1322 | __cfqq = cfq_rb_first(service_tree); |
48e025e6 CZ |
1323 | rb_key += __cfqq ? __cfqq->rb_key : jiffies; |
1324 | } | |
1da177e4 | 1325 | |
d9e7620e | 1326 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) { |
dae739eb | 1327 | new_cfqq = 0; |
99f9628a | 1328 | /* |
d9e7620e | 1329 | * same position, nothing more to do |
99f9628a | 1330 | */ |
c0324a02 CZ |
1331 | if (rb_key == cfqq->rb_key && |
1332 | cfqq->service_tree == service_tree) | |
d9e7620e | 1333 | return; |
1da177e4 | 1334 | |
aa6f6a3d CZ |
1335 | cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree); |
1336 | cfqq->service_tree = NULL; | |
1da177e4 | 1337 | } |
d9e7620e | 1338 | |
498d3aa2 | 1339 | left = 1; |
0871714e | 1340 | parent = NULL; |
aa6f6a3d CZ |
1341 | cfqq->service_tree = service_tree; |
1342 | p = &service_tree->rb.rb_node; | |
d9e7620e | 1343 | while (*p) { |
67060e37 | 1344 | struct rb_node **n; |
cc09e299 | 1345 | |
d9e7620e JA |
1346 | parent = *p; |
1347 | __cfqq = rb_entry(parent, struct cfq_queue, rb_node); | |
1348 | ||
0c534e0a | 1349 | /* |
c0324a02 | 1350 | * sort by key, that represents service time. |
0c534e0a | 1351 | */ |
c0324a02 | 1352 | if (time_before(rb_key, __cfqq->rb_key)) |
67060e37 | 1353 | n = &(*p)->rb_left; |
c0324a02 | 1354 | else { |
67060e37 | 1355 | n = &(*p)->rb_right; |
cc09e299 | 1356 | left = 0; |
c0324a02 | 1357 | } |
67060e37 JA |
1358 | |
1359 | p = n; | |
d9e7620e JA |
1360 | } |
1361 | ||
cc09e299 | 1362 | if (left) |
aa6f6a3d | 1363 | service_tree->left = &cfqq->rb_node; |
cc09e299 | 1364 | |
d9e7620e JA |
1365 | cfqq->rb_key = rb_key; |
1366 | rb_link_node(&cfqq->rb_node, parent, p); | |
aa6f6a3d CZ |
1367 | rb_insert_color(&cfqq->rb_node, &service_tree->rb); |
1368 | service_tree->count++; | |
20359f27 | 1369 | if (add_front || !new_cfqq) |
dae739eb | 1370 | return; |
8184f93e | 1371 | cfq_group_notify_queue_add(cfqd, cfqq->cfqg); |
1da177e4 LT |
1372 | } |
1373 | ||
a36e71f9 | 1374 | static struct cfq_queue * |
f2d1f0ae JA |
1375 | cfq_prio_tree_lookup(struct cfq_data *cfqd, struct rb_root *root, |
1376 | sector_t sector, struct rb_node **ret_parent, | |
1377 | struct rb_node ***rb_link) | |
a36e71f9 | 1378 | { |
a36e71f9 JA |
1379 | struct rb_node **p, *parent; |
1380 | struct cfq_queue *cfqq = NULL; | |
1381 | ||
1382 | parent = NULL; | |
1383 | p = &root->rb_node; | |
1384 | while (*p) { | |
1385 | struct rb_node **n; | |
1386 | ||
1387 | parent = *p; | |
1388 | cfqq = rb_entry(parent, struct cfq_queue, p_node); | |
1389 | ||
1390 | /* | |
1391 | * Sort strictly based on sector. Smallest to the left, | |
1392 | * largest to the right. | |
1393 | */ | |
2e46e8b2 | 1394 | if (sector > blk_rq_pos(cfqq->next_rq)) |
a36e71f9 | 1395 | n = &(*p)->rb_right; |
2e46e8b2 | 1396 | else if (sector < blk_rq_pos(cfqq->next_rq)) |
a36e71f9 JA |
1397 | n = &(*p)->rb_left; |
1398 | else | |
1399 | break; | |
1400 | p = n; | |
3ac6c9f8 | 1401 | cfqq = NULL; |
a36e71f9 JA |
1402 | } |
1403 | ||
1404 | *ret_parent = parent; | |
1405 | if (rb_link) | |
1406 | *rb_link = p; | |
3ac6c9f8 | 1407 | return cfqq; |
a36e71f9 JA |
1408 | } |
1409 | ||
1410 | static void cfq_prio_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1411 | { | |
a36e71f9 JA |
1412 | struct rb_node **p, *parent; |
1413 | struct cfq_queue *__cfqq; | |
1414 | ||
f2d1f0ae JA |
1415 | if (cfqq->p_root) { |
1416 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
1417 | cfqq->p_root = NULL; | |
1418 | } | |
a36e71f9 JA |
1419 | |
1420 | if (cfq_class_idle(cfqq)) | |
1421 | return; | |
1422 | if (!cfqq->next_rq) | |
1423 | return; | |
1424 | ||
f2d1f0ae | 1425 | cfqq->p_root = &cfqd->prio_trees[cfqq->org_ioprio]; |
2e46e8b2 TH |
1426 | __cfqq = cfq_prio_tree_lookup(cfqd, cfqq->p_root, |
1427 | blk_rq_pos(cfqq->next_rq), &parent, &p); | |
3ac6c9f8 JA |
1428 | if (!__cfqq) { |
1429 | rb_link_node(&cfqq->p_node, parent, p); | |
f2d1f0ae JA |
1430 | rb_insert_color(&cfqq->p_node, cfqq->p_root); |
1431 | } else | |
1432 | cfqq->p_root = NULL; | |
a36e71f9 JA |
1433 | } |
1434 | ||
498d3aa2 JA |
1435 | /* |
1436 | * Update cfqq's position in the service tree. | |
1437 | */ | |
edd75ffd | 1438 | static void cfq_resort_rr_list(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
6d048f53 | 1439 | { |
6d048f53 JA |
1440 | /* |
1441 | * Resorting requires the cfqq to be on the RR list already. | |
1442 | */ | |
a36e71f9 | 1443 | if (cfq_cfqq_on_rr(cfqq)) { |
edd75ffd | 1444 | cfq_service_tree_add(cfqd, cfqq, 0); |
a36e71f9 JA |
1445 | cfq_prio_tree_add(cfqd, cfqq); |
1446 | } | |
6d048f53 JA |
1447 | } |
1448 | ||
1da177e4 LT |
1449 | /* |
1450 | * add to busy list of queues for service, trying to be fair in ordering | |
22e2c507 | 1451 | * the pending list according to last request service |
1da177e4 | 1452 | */ |
febffd61 | 1453 | static void cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 1454 | { |
7b679138 | 1455 | cfq_log_cfqq(cfqd, cfqq, "add_to_rr"); |
3b18152c JA |
1456 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
1457 | cfq_mark_cfqq_on_rr(cfqq); | |
1da177e4 | 1458 | cfqd->busy_queues++; |
ef8a41df SL |
1459 | if (cfq_cfqq_sync(cfqq)) |
1460 | cfqd->busy_sync_queues++; | |
1da177e4 | 1461 | |
edd75ffd | 1462 | cfq_resort_rr_list(cfqd, cfqq); |
1da177e4 LT |
1463 | } |
1464 | ||
498d3aa2 JA |
1465 | /* |
1466 | * Called when the cfqq no longer has requests pending, remove it from | |
1467 | * the service tree. | |
1468 | */ | |
febffd61 | 1469 | static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 1470 | { |
7b679138 | 1471 | cfq_log_cfqq(cfqd, cfqq, "del_from_rr"); |
3b18152c JA |
1472 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
1473 | cfq_clear_cfqq_on_rr(cfqq); | |
1da177e4 | 1474 | |
aa6f6a3d CZ |
1475 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) { |
1476 | cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree); | |
1477 | cfqq->service_tree = NULL; | |
1478 | } | |
f2d1f0ae JA |
1479 | if (cfqq->p_root) { |
1480 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
1481 | cfqq->p_root = NULL; | |
1482 | } | |
d9e7620e | 1483 | |
8184f93e | 1484 | cfq_group_notify_queue_del(cfqd, cfqq->cfqg); |
1da177e4 LT |
1485 | BUG_ON(!cfqd->busy_queues); |
1486 | cfqd->busy_queues--; | |
ef8a41df SL |
1487 | if (cfq_cfqq_sync(cfqq)) |
1488 | cfqd->busy_sync_queues--; | |
1da177e4 LT |
1489 | } |
1490 | ||
1491 | /* | |
1492 | * rb tree support functions | |
1493 | */ | |
febffd61 | 1494 | static void cfq_del_rq_rb(struct request *rq) |
1da177e4 | 1495 | { |
5e705374 | 1496 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
5e705374 | 1497 | const int sync = rq_is_sync(rq); |
1da177e4 | 1498 | |
b4878f24 JA |
1499 | BUG_ON(!cfqq->queued[sync]); |
1500 | cfqq->queued[sync]--; | |
1da177e4 | 1501 | |
5e705374 | 1502 | elv_rb_del(&cfqq->sort_list, rq); |
1da177e4 | 1503 | |
f04a6424 VG |
1504 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) { |
1505 | /* | |
1506 | * Queue will be deleted from service tree when we actually | |
1507 | * expire it later. Right now just remove it from prio tree | |
1508 | * as it is empty. | |
1509 | */ | |
1510 | if (cfqq->p_root) { | |
1511 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
1512 | cfqq->p_root = NULL; | |
1513 | } | |
1514 | } | |
1da177e4 LT |
1515 | } |
1516 | ||
5e705374 | 1517 | static void cfq_add_rq_rb(struct request *rq) |
1da177e4 | 1518 | { |
5e705374 | 1519 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
1da177e4 | 1520 | struct cfq_data *cfqd = cfqq->cfqd; |
796d5116 | 1521 | struct request *prev; |
1da177e4 | 1522 | |
5380a101 | 1523 | cfqq->queued[rq_is_sync(rq)]++; |
1da177e4 | 1524 | |
796d5116 | 1525 | elv_rb_add(&cfqq->sort_list, rq); |
5fccbf61 JA |
1526 | |
1527 | if (!cfq_cfqq_on_rr(cfqq)) | |
1528 | cfq_add_cfqq_rr(cfqd, cfqq); | |
5044eed4 JA |
1529 | |
1530 | /* | |
1531 | * check if this request is a better next-serve candidate | |
1532 | */ | |
a36e71f9 | 1533 | prev = cfqq->next_rq; |
cf7c25cf | 1534 | cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq, cfqd->last_position); |
a36e71f9 JA |
1535 | |
1536 | /* | |
1537 | * adjust priority tree position, if ->next_rq changes | |
1538 | */ | |
1539 | if (prev != cfqq->next_rq) | |
1540 | cfq_prio_tree_add(cfqd, cfqq); | |
1541 | ||
5044eed4 | 1542 | BUG_ON(!cfqq->next_rq); |
1da177e4 LT |
1543 | } |
1544 | ||
febffd61 | 1545 | static void cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq) |
1da177e4 | 1546 | { |
5380a101 JA |
1547 | elv_rb_del(&cfqq->sort_list, rq); |
1548 | cfqq->queued[rq_is_sync(rq)]--; | |
e98ef89b VG |
1549 | cfq_blkiocg_update_io_remove_stats(&(RQ_CFQG(rq))->blkg, |
1550 | rq_data_dir(rq), rq_is_sync(rq)); | |
5e705374 | 1551 | cfq_add_rq_rb(rq); |
e98ef89b | 1552 | cfq_blkiocg_update_io_add_stats(&(RQ_CFQG(rq))->blkg, |
7f1dc8a2 VG |
1553 | &cfqq->cfqd->serving_group->blkg, rq_data_dir(rq), |
1554 | rq_is_sync(rq)); | |
1da177e4 LT |
1555 | } |
1556 | ||
206dc69b JA |
1557 | static struct request * |
1558 | cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio) | |
1da177e4 | 1559 | { |
206dc69b | 1560 | struct task_struct *tsk = current; |
91fac317 | 1561 | struct cfq_io_context *cic; |
206dc69b | 1562 | struct cfq_queue *cfqq; |
1da177e4 | 1563 | |
4ac845a2 | 1564 | cic = cfq_cic_lookup(cfqd, tsk->io_context); |
91fac317 VT |
1565 | if (!cic) |
1566 | return NULL; | |
1567 | ||
1568 | cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); | |
89850f7e JA |
1569 | if (cfqq) { |
1570 | sector_t sector = bio->bi_sector + bio_sectors(bio); | |
1571 | ||
21183b07 | 1572 | return elv_rb_find(&cfqq->sort_list, sector); |
89850f7e | 1573 | } |
1da177e4 | 1574 | |
1da177e4 LT |
1575 | return NULL; |
1576 | } | |
1577 | ||
165125e1 | 1578 | static void cfq_activate_request(struct request_queue *q, struct request *rq) |
1da177e4 | 1579 | { |
22e2c507 | 1580 | struct cfq_data *cfqd = q->elevator->elevator_data; |
3b18152c | 1581 | |
53c583d2 | 1582 | cfqd->rq_in_driver++; |
7b679138 | 1583 | cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "activate rq, drv=%d", |
53c583d2 | 1584 | cfqd->rq_in_driver); |
25776e35 | 1585 | |
5b93629b | 1586 | cfqd->last_position = blk_rq_pos(rq) + blk_rq_sectors(rq); |
1da177e4 LT |
1587 | } |
1588 | ||
165125e1 | 1589 | static void cfq_deactivate_request(struct request_queue *q, struct request *rq) |
1da177e4 | 1590 | { |
b4878f24 JA |
1591 | struct cfq_data *cfqd = q->elevator->elevator_data; |
1592 | ||
53c583d2 CZ |
1593 | WARN_ON(!cfqd->rq_in_driver); |
1594 | cfqd->rq_in_driver--; | |
7b679138 | 1595 | cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "deactivate rq, drv=%d", |
53c583d2 | 1596 | cfqd->rq_in_driver); |
1da177e4 LT |
1597 | } |
1598 | ||
b4878f24 | 1599 | static void cfq_remove_request(struct request *rq) |
1da177e4 | 1600 | { |
5e705374 | 1601 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
21183b07 | 1602 | |
5e705374 JA |
1603 | if (cfqq->next_rq == rq) |
1604 | cfqq->next_rq = cfq_find_next_rq(cfqq->cfqd, cfqq, rq); | |
1da177e4 | 1605 | |
b4878f24 | 1606 | list_del_init(&rq->queuelist); |
5e705374 | 1607 | cfq_del_rq_rb(rq); |
374f84ac | 1608 | |
45333d5a | 1609 | cfqq->cfqd->rq_queued--; |
e98ef89b VG |
1610 | cfq_blkiocg_update_io_remove_stats(&(RQ_CFQG(rq))->blkg, |
1611 | rq_data_dir(rq), rq_is_sync(rq)); | |
65299a3b CH |
1612 | if (rq->cmd_flags & REQ_PRIO) { |
1613 | WARN_ON(!cfqq->prio_pending); | |
1614 | cfqq->prio_pending--; | |
b53d1ed7 | 1615 | } |
1da177e4 LT |
1616 | } |
1617 | ||
165125e1 JA |
1618 | static int cfq_merge(struct request_queue *q, struct request **req, |
1619 | struct bio *bio) | |
1da177e4 LT |
1620 | { |
1621 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1622 | struct request *__rq; | |
1da177e4 | 1623 | |
206dc69b | 1624 | __rq = cfq_find_rq_fmerge(cfqd, bio); |
22e2c507 | 1625 | if (__rq && elv_rq_merge_ok(__rq, bio)) { |
9817064b JA |
1626 | *req = __rq; |
1627 | return ELEVATOR_FRONT_MERGE; | |
1da177e4 LT |
1628 | } |
1629 | ||
1630 | return ELEVATOR_NO_MERGE; | |
1da177e4 LT |
1631 | } |
1632 | ||
165125e1 | 1633 | static void cfq_merged_request(struct request_queue *q, struct request *req, |
21183b07 | 1634 | int type) |
1da177e4 | 1635 | { |
21183b07 | 1636 | if (type == ELEVATOR_FRONT_MERGE) { |
5e705374 | 1637 | struct cfq_queue *cfqq = RQ_CFQQ(req); |
1da177e4 | 1638 | |
5e705374 | 1639 | cfq_reposition_rq_rb(cfqq, req); |
1da177e4 | 1640 | } |
1da177e4 LT |
1641 | } |
1642 | ||
812d4026 DS |
1643 | static void cfq_bio_merged(struct request_queue *q, struct request *req, |
1644 | struct bio *bio) | |
1645 | { | |
e98ef89b VG |
1646 | cfq_blkiocg_update_io_merged_stats(&(RQ_CFQG(req))->blkg, |
1647 | bio_data_dir(bio), cfq_bio_sync(bio)); | |
812d4026 DS |
1648 | } |
1649 | ||
1da177e4 | 1650 | static void |
165125e1 | 1651 | cfq_merged_requests(struct request_queue *q, struct request *rq, |
1da177e4 LT |
1652 | struct request *next) |
1653 | { | |
cf7c25cf | 1654 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 JA |
1655 | /* |
1656 | * reposition in fifo if next is older than rq | |
1657 | */ | |
1658 | if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && | |
30996f40 | 1659 | time_before(rq_fifo_time(next), rq_fifo_time(rq))) { |
22e2c507 | 1660 | list_move(&rq->queuelist, &next->queuelist); |
30996f40 JA |
1661 | rq_set_fifo_time(rq, rq_fifo_time(next)); |
1662 | } | |
22e2c507 | 1663 | |
cf7c25cf CZ |
1664 | if (cfqq->next_rq == next) |
1665 | cfqq->next_rq = rq; | |
b4878f24 | 1666 | cfq_remove_request(next); |
e98ef89b VG |
1667 | cfq_blkiocg_update_io_merged_stats(&(RQ_CFQG(rq))->blkg, |
1668 | rq_data_dir(next), rq_is_sync(next)); | |
22e2c507 JA |
1669 | } |
1670 | ||
165125e1 | 1671 | static int cfq_allow_merge(struct request_queue *q, struct request *rq, |
da775265 JA |
1672 | struct bio *bio) |
1673 | { | |
1674 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
91fac317 | 1675 | struct cfq_io_context *cic; |
da775265 | 1676 | struct cfq_queue *cfqq; |
da775265 JA |
1677 | |
1678 | /* | |
ec8acb69 | 1679 | * Disallow merge of a sync bio into an async request. |
da775265 | 1680 | */ |
91fac317 | 1681 | if (cfq_bio_sync(bio) && !rq_is_sync(rq)) |
a6151c3a | 1682 | return false; |
da775265 JA |
1683 | |
1684 | /* | |
719d3402 JA |
1685 | * Lookup the cfqq that this bio will be queued with. Allow |
1686 | * merge only if rq is queued there. | |
da775265 | 1687 | */ |
4ac845a2 | 1688 | cic = cfq_cic_lookup(cfqd, current->io_context); |
91fac317 | 1689 | if (!cic) |
a6151c3a | 1690 | return false; |
719d3402 | 1691 | |
91fac317 | 1692 | cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); |
a6151c3a | 1693 | return cfqq == RQ_CFQQ(rq); |
da775265 JA |
1694 | } |
1695 | ||
812df48d DS |
1696 | static inline void cfq_del_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1697 | { | |
1698 | del_timer(&cfqd->idle_slice_timer); | |
e98ef89b | 1699 | cfq_blkiocg_update_idle_time_stats(&cfqq->cfqg->blkg); |
812df48d DS |
1700 | } |
1701 | ||
febffd61 JA |
1702 | static void __cfq_set_active_queue(struct cfq_data *cfqd, |
1703 | struct cfq_queue *cfqq) | |
22e2c507 JA |
1704 | { |
1705 | if (cfqq) { | |
b1ffe737 DS |
1706 | cfq_log_cfqq(cfqd, cfqq, "set_active wl_prio:%d wl_type:%d", |
1707 | cfqd->serving_prio, cfqd->serving_type); | |
62a37f6b JT |
1708 | cfq_blkiocg_update_avg_queue_size_stats(&cfqq->cfqg->blkg); |
1709 | cfqq->slice_start = 0; | |
1710 | cfqq->dispatch_start = jiffies; | |
1711 | cfqq->allocated_slice = 0; | |
1712 | cfqq->slice_end = 0; | |
1713 | cfqq->slice_dispatch = 0; | |
1714 | cfqq->nr_sectors = 0; | |
1715 | ||
1716 | cfq_clear_cfqq_wait_request(cfqq); | |
1717 | cfq_clear_cfqq_must_dispatch(cfqq); | |
1718 | cfq_clear_cfqq_must_alloc_slice(cfqq); | |
1719 | cfq_clear_cfqq_fifo_expire(cfqq); | |
1720 | cfq_mark_cfqq_slice_new(cfqq); | |
1721 | ||
1722 | cfq_del_timer(cfqd, cfqq); | |
22e2c507 JA |
1723 | } |
1724 | ||
1725 | cfqd->active_queue = cfqq; | |
1726 | } | |
1727 | ||
7b14e3b5 JA |
1728 | /* |
1729 | * current cfqq expired its slice (or was too idle), select new one | |
1730 | */ | |
1731 | static void | |
1732 | __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
e5ff082e | 1733 | bool timed_out) |
7b14e3b5 | 1734 | { |
7b679138 JA |
1735 | cfq_log_cfqq(cfqd, cfqq, "slice expired t=%d", timed_out); |
1736 | ||
7b14e3b5 | 1737 | if (cfq_cfqq_wait_request(cfqq)) |
812df48d | 1738 | cfq_del_timer(cfqd, cfqq); |
7b14e3b5 | 1739 | |
7b14e3b5 | 1740 | cfq_clear_cfqq_wait_request(cfqq); |
f75edf2d | 1741 | cfq_clear_cfqq_wait_busy(cfqq); |
7b14e3b5 | 1742 | |
ae54abed SL |
1743 | /* |
1744 | * If this cfqq is shared between multiple processes, check to | |
1745 | * make sure that those processes are still issuing I/Os within | |
1746 | * the mean seek distance. If not, it may be time to break the | |
1747 | * queues apart again. | |
1748 | */ | |
1749 | if (cfq_cfqq_coop(cfqq) && CFQQ_SEEKY(cfqq)) | |
1750 | cfq_mark_cfqq_split_coop(cfqq); | |
1751 | ||
7b14e3b5 | 1752 | /* |
6084cdda | 1753 | * store what was left of this slice, if the queue idled/timed out |
7b14e3b5 | 1754 | */ |
c553f8e3 SL |
1755 | if (timed_out) { |
1756 | if (cfq_cfqq_slice_new(cfqq)) | |
ba5bd520 | 1757 | cfqq->slice_resid = cfq_scaled_cfqq_slice(cfqd, cfqq); |
c553f8e3 SL |
1758 | else |
1759 | cfqq->slice_resid = cfqq->slice_end - jiffies; | |
7b679138 JA |
1760 | cfq_log_cfqq(cfqd, cfqq, "resid=%ld", cfqq->slice_resid); |
1761 | } | |
7b14e3b5 | 1762 | |
e5ff082e | 1763 | cfq_group_served(cfqd, cfqq->cfqg, cfqq); |
dae739eb | 1764 | |
f04a6424 VG |
1765 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) |
1766 | cfq_del_cfqq_rr(cfqd, cfqq); | |
1767 | ||
edd75ffd | 1768 | cfq_resort_rr_list(cfqd, cfqq); |
7b14e3b5 JA |
1769 | |
1770 | if (cfqq == cfqd->active_queue) | |
1771 | cfqd->active_queue = NULL; | |
1772 | ||
1773 | if (cfqd->active_cic) { | |
1774 | put_io_context(cfqd->active_cic->ioc); | |
1775 | cfqd->active_cic = NULL; | |
1776 | } | |
7b14e3b5 JA |
1777 | } |
1778 | ||
e5ff082e | 1779 | static inline void cfq_slice_expired(struct cfq_data *cfqd, bool timed_out) |
7b14e3b5 JA |
1780 | { |
1781 | struct cfq_queue *cfqq = cfqd->active_queue; | |
1782 | ||
1783 | if (cfqq) | |
e5ff082e | 1784 | __cfq_slice_expired(cfqd, cfqq, timed_out); |
7b14e3b5 JA |
1785 | } |
1786 | ||
498d3aa2 JA |
1787 | /* |
1788 | * Get next queue for service. Unless we have a queue preemption, | |
1789 | * we'll simply select the first cfqq in the service tree. | |
1790 | */ | |
6d048f53 | 1791 | static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd) |
22e2c507 | 1792 | { |
c0324a02 | 1793 | struct cfq_rb_root *service_tree = |
cdb16e8f | 1794 | service_tree_for(cfqd->serving_group, cfqd->serving_prio, |
65b32a57 | 1795 | cfqd->serving_type); |
d9e7620e | 1796 | |
f04a6424 VG |
1797 | if (!cfqd->rq_queued) |
1798 | return NULL; | |
1799 | ||
1fa8f6d6 VG |
1800 | /* There is nothing to dispatch */ |
1801 | if (!service_tree) | |
1802 | return NULL; | |
c0324a02 CZ |
1803 | if (RB_EMPTY_ROOT(&service_tree->rb)) |
1804 | return NULL; | |
1805 | return cfq_rb_first(service_tree); | |
6d048f53 JA |
1806 | } |
1807 | ||
f04a6424 VG |
1808 | static struct cfq_queue *cfq_get_next_queue_forced(struct cfq_data *cfqd) |
1809 | { | |
25fb5169 | 1810 | struct cfq_group *cfqg; |
f04a6424 VG |
1811 | struct cfq_queue *cfqq; |
1812 | int i, j; | |
1813 | struct cfq_rb_root *st; | |
1814 | ||
1815 | if (!cfqd->rq_queued) | |
1816 | return NULL; | |
1817 | ||
25fb5169 VG |
1818 | cfqg = cfq_get_next_cfqg(cfqd); |
1819 | if (!cfqg) | |
1820 | return NULL; | |
1821 | ||
f04a6424 VG |
1822 | for_each_cfqg_st(cfqg, i, j, st) |
1823 | if ((cfqq = cfq_rb_first(st)) != NULL) | |
1824 | return cfqq; | |
1825 | return NULL; | |
1826 | } | |
1827 | ||
498d3aa2 JA |
1828 | /* |
1829 | * Get and set a new active queue for service. | |
1830 | */ | |
a36e71f9 JA |
1831 | static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd, |
1832 | struct cfq_queue *cfqq) | |
6d048f53 | 1833 | { |
e00ef799 | 1834 | if (!cfqq) |
a36e71f9 | 1835 | cfqq = cfq_get_next_queue(cfqd); |
6d048f53 | 1836 | |
22e2c507 | 1837 | __cfq_set_active_queue(cfqd, cfqq); |
3b18152c | 1838 | return cfqq; |
22e2c507 JA |
1839 | } |
1840 | ||
d9e7620e JA |
1841 | static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd, |
1842 | struct request *rq) | |
1843 | { | |
83096ebf TH |
1844 | if (blk_rq_pos(rq) >= cfqd->last_position) |
1845 | return blk_rq_pos(rq) - cfqd->last_position; | |
d9e7620e | 1846 | else |
83096ebf | 1847 | return cfqd->last_position - blk_rq_pos(rq); |
d9e7620e JA |
1848 | } |
1849 | ||
b2c18e1e | 1850 | static inline int cfq_rq_close(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
e9ce335d | 1851 | struct request *rq) |
6d048f53 | 1852 | { |
e9ce335d | 1853 | return cfq_dist_from_last(cfqd, rq) <= CFQQ_CLOSE_THR; |
6d048f53 JA |
1854 | } |
1855 | ||
a36e71f9 JA |
1856 | static struct cfq_queue *cfqq_close(struct cfq_data *cfqd, |
1857 | struct cfq_queue *cur_cfqq) | |
1858 | { | |
f2d1f0ae | 1859 | struct rb_root *root = &cfqd->prio_trees[cur_cfqq->org_ioprio]; |
a36e71f9 JA |
1860 | struct rb_node *parent, *node; |
1861 | struct cfq_queue *__cfqq; | |
1862 | sector_t sector = cfqd->last_position; | |
1863 | ||
1864 | if (RB_EMPTY_ROOT(root)) | |
1865 | return NULL; | |
1866 | ||
1867 | /* | |
1868 | * First, if we find a request starting at the end of the last | |
1869 | * request, choose it. | |
1870 | */ | |
f2d1f0ae | 1871 | __cfqq = cfq_prio_tree_lookup(cfqd, root, sector, &parent, NULL); |
a36e71f9 JA |
1872 | if (__cfqq) |
1873 | return __cfqq; | |
1874 | ||
1875 | /* | |
1876 | * If the exact sector wasn't found, the parent of the NULL leaf | |
1877 | * will contain the closest sector. | |
1878 | */ | |
1879 | __cfqq = rb_entry(parent, struct cfq_queue, p_node); | |
e9ce335d | 1880 | if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq)) |
a36e71f9 JA |
1881 | return __cfqq; |
1882 | ||
2e46e8b2 | 1883 | if (blk_rq_pos(__cfqq->next_rq) < sector) |
a36e71f9 JA |
1884 | node = rb_next(&__cfqq->p_node); |
1885 | else | |
1886 | node = rb_prev(&__cfqq->p_node); | |
1887 | if (!node) | |
1888 | return NULL; | |
1889 | ||
1890 | __cfqq = rb_entry(node, struct cfq_queue, p_node); | |
e9ce335d | 1891 | if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq)) |
a36e71f9 JA |
1892 | return __cfqq; |
1893 | ||
1894 | return NULL; | |
1895 | } | |
1896 | ||
1897 | /* | |
1898 | * cfqd - obvious | |
1899 | * cur_cfqq - passed in so that we don't decide that the current queue is | |
1900 | * closely cooperating with itself. | |
1901 | * | |
1902 | * So, basically we're assuming that that cur_cfqq has dispatched at least | |
1903 | * one request, and that cfqd->last_position reflects a position on the disk | |
1904 | * associated with the I/O issued by cur_cfqq. I'm not sure this is a valid | |
1905 | * assumption. | |
1906 | */ | |
1907 | static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd, | |
b3b6d040 | 1908 | struct cfq_queue *cur_cfqq) |
6d048f53 | 1909 | { |
a36e71f9 JA |
1910 | struct cfq_queue *cfqq; |
1911 | ||
39c01b21 DS |
1912 | if (cfq_class_idle(cur_cfqq)) |
1913 | return NULL; | |
e6c5bc73 JM |
1914 | if (!cfq_cfqq_sync(cur_cfqq)) |
1915 | return NULL; | |
1916 | if (CFQQ_SEEKY(cur_cfqq)) | |
1917 | return NULL; | |
1918 | ||
b9d8f4c7 GJ |
1919 | /* |
1920 | * Don't search priority tree if it's the only queue in the group. | |
1921 | */ | |
1922 | if (cur_cfqq->cfqg->nr_cfqq == 1) | |
1923 | return NULL; | |
1924 | ||
6d048f53 | 1925 | /* |
d9e7620e JA |
1926 | * We should notice if some of the queues are cooperating, eg |
1927 | * working closely on the same area of the disk. In that case, | |
1928 | * we can group them together and don't waste time idling. | |
6d048f53 | 1929 | */ |
a36e71f9 JA |
1930 | cfqq = cfqq_close(cfqd, cur_cfqq); |
1931 | if (!cfqq) | |
1932 | return NULL; | |
1933 | ||
8682e1f1 VG |
1934 | /* If new queue belongs to different cfq_group, don't choose it */ |
1935 | if (cur_cfqq->cfqg != cfqq->cfqg) | |
1936 | return NULL; | |
1937 | ||
df5fe3e8 JM |
1938 | /* |
1939 | * It only makes sense to merge sync queues. | |
1940 | */ | |
1941 | if (!cfq_cfqq_sync(cfqq)) | |
1942 | return NULL; | |
e6c5bc73 JM |
1943 | if (CFQQ_SEEKY(cfqq)) |
1944 | return NULL; | |
df5fe3e8 | 1945 | |
c0324a02 CZ |
1946 | /* |
1947 | * Do not merge queues of different priority classes | |
1948 | */ | |
1949 | if (cfq_class_rt(cfqq) != cfq_class_rt(cur_cfqq)) | |
1950 | return NULL; | |
1951 | ||
a36e71f9 | 1952 | return cfqq; |
6d048f53 JA |
1953 | } |
1954 | ||
a6d44e98 CZ |
1955 | /* |
1956 | * Determine whether we should enforce idle window for this queue. | |
1957 | */ | |
1958 | ||
1959 | static bool cfq_should_idle(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1960 | { | |
1961 | enum wl_prio_t prio = cfqq_prio(cfqq); | |
718eee05 | 1962 | struct cfq_rb_root *service_tree = cfqq->service_tree; |
a6d44e98 | 1963 | |
f04a6424 VG |
1964 | BUG_ON(!service_tree); |
1965 | BUG_ON(!service_tree->count); | |
1966 | ||
b6508c16 VG |
1967 | if (!cfqd->cfq_slice_idle) |
1968 | return false; | |
1969 | ||
a6d44e98 CZ |
1970 | /* We never do for idle class queues. */ |
1971 | if (prio == IDLE_WORKLOAD) | |
1972 | return false; | |
1973 | ||
1974 | /* We do for queues that were marked with idle window flag. */ | |
3c764b7a SL |
1975 | if (cfq_cfqq_idle_window(cfqq) && |
1976 | !(blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag)) | |
a6d44e98 CZ |
1977 | return true; |
1978 | ||
1979 | /* | |
1980 | * Otherwise, we do only if they are the last ones | |
1981 | * in their service tree. | |
1982 | */ | |
f5f2b6ce SL |
1983 | if (service_tree->count == 1 && cfq_cfqq_sync(cfqq) && |
1984 | !cfq_io_thinktime_big(cfqd, &service_tree->ttime, false)) | |
c1e44756 | 1985 | return true; |
b1ffe737 DS |
1986 | cfq_log_cfqq(cfqd, cfqq, "Not idling. st->count:%d", |
1987 | service_tree->count); | |
c1e44756 | 1988 | return false; |
a6d44e98 CZ |
1989 | } |
1990 | ||
6d048f53 | 1991 | static void cfq_arm_slice_timer(struct cfq_data *cfqd) |
22e2c507 | 1992 | { |
1792669c | 1993 | struct cfq_queue *cfqq = cfqd->active_queue; |
206dc69b | 1994 | struct cfq_io_context *cic; |
80bdf0c7 | 1995 | unsigned long sl, group_idle = 0; |
7b14e3b5 | 1996 | |
a68bbddb | 1997 | /* |
f7d7b7a7 JA |
1998 | * SSD device without seek penalty, disable idling. But only do so |
1999 | * for devices that support queuing, otherwise we still have a problem | |
2000 | * with sync vs async workloads. | |
a68bbddb | 2001 | */ |
f7d7b7a7 | 2002 | if (blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag) |
a68bbddb JA |
2003 | return; |
2004 | ||
dd67d051 | 2005 | WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list)); |
6d048f53 | 2006 | WARN_ON(cfq_cfqq_slice_new(cfqq)); |
22e2c507 JA |
2007 | |
2008 | /* | |
2009 | * idle is disabled, either manually or by past process history | |
2010 | */ | |
80bdf0c7 VG |
2011 | if (!cfq_should_idle(cfqd, cfqq)) { |
2012 | /* no queue idling. Check for group idling */ | |
2013 | if (cfqd->cfq_group_idle) | |
2014 | group_idle = cfqd->cfq_group_idle; | |
2015 | else | |
2016 | return; | |
2017 | } | |
6d048f53 | 2018 | |
7b679138 | 2019 | /* |
8e550632 | 2020 | * still active requests from this queue, don't idle |
7b679138 | 2021 | */ |
8e550632 | 2022 | if (cfqq->dispatched) |
7b679138 JA |
2023 | return; |
2024 | ||
22e2c507 JA |
2025 | /* |
2026 | * task has exited, don't wait | |
2027 | */ | |
206dc69b | 2028 | cic = cfqd->active_cic; |
66dac98e | 2029 | if (!cic || !atomic_read(&cic->ioc->nr_tasks)) |
6d048f53 JA |
2030 | return; |
2031 | ||
355b659c CZ |
2032 | /* |
2033 | * If our average think time is larger than the remaining time | |
2034 | * slice, then don't idle. This avoids overrunning the allotted | |
2035 | * time slice. | |
2036 | */ | |
383cd721 SL |
2037 | if (sample_valid(cic->ttime.ttime_samples) && |
2038 | (cfqq->slice_end - jiffies < cic->ttime.ttime_mean)) { | |
fd16d263 | 2039 | cfq_log_cfqq(cfqd, cfqq, "Not idling. think_time:%lu", |
383cd721 | 2040 | cic->ttime.ttime_mean); |
355b659c | 2041 | return; |
b1ffe737 | 2042 | } |
355b659c | 2043 | |
80bdf0c7 VG |
2044 | /* There are other queues in the group, don't do group idle */ |
2045 | if (group_idle && cfqq->cfqg->nr_cfqq > 1) | |
2046 | return; | |
2047 | ||
3b18152c | 2048 | cfq_mark_cfqq_wait_request(cfqq); |
22e2c507 | 2049 | |
80bdf0c7 VG |
2050 | if (group_idle) |
2051 | sl = cfqd->cfq_group_idle; | |
2052 | else | |
2053 | sl = cfqd->cfq_slice_idle; | |
206dc69b | 2054 | |
7b14e3b5 | 2055 | mod_timer(&cfqd->idle_slice_timer, jiffies + sl); |
e98ef89b | 2056 | cfq_blkiocg_update_set_idle_time_stats(&cfqq->cfqg->blkg); |
80bdf0c7 VG |
2057 | cfq_log_cfqq(cfqd, cfqq, "arm_idle: %lu group_idle: %d", sl, |
2058 | group_idle ? 1 : 0); | |
1da177e4 LT |
2059 | } |
2060 | ||
498d3aa2 JA |
2061 | /* |
2062 | * Move request from internal lists to the request queue dispatch list. | |
2063 | */ | |
165125e1 | 2064 | static void cfq_dispatch_insert(struct request_queue *q, struct request *rq) |
1da177e4 | 2065 | { |
3ed9a296 | 2066 | struct cfq_data *cfqd = q->elevator->elevator_data; |
5e705374 | 2067 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 | 2068 | |
7b679138 JA |
2069 | cfq_log_cfqq(cfqd, cfqq, "dispatch_insert"); |
2070 | ||
06d21886 | 2071 | cfqq->next_rq = cfq_find_next_rq(cfqd, cfqq, rq); |
5380a101 | 2072 | cfq_remove_request(rq); |
6d048f53 | 2073 | cfqq->dispatched++; |
80bdf0c7 | 2074 | (RQ_CFQG(rq))->dispatched++; |
5380a101 | 2075 | elv_dispatch_sort(q, rq); |
3ed9a296 | 2076 | |
53c583d2 | 2077 | cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]++; |
c4e7893e | 2078 | cfqq->nr_sectors += blk_rq_sectors(rq); |
e98ef89b | 2079 | cfq_blkiocg_update_dispatch_stats(&cfqq->cfqg->blkg, blk_rq_bytes(rq), |
84c124da | 2080 | rq_data_dir(rq), rq_is_sync(rq)); |
1da177e4 LT |
2081 | } |
2082 | ||
2083 | /* | |
2084 | * return expired entry, or NULL to just start from scratch in rbtree | |
2085 | */ | |
febffd61 | 2086 | static struct request *cfq_check_fifo(struct cfq_queue *cfqq) |
1da177e4 | 2087 | { |
30996f40 | 2088 | struct request *rq = NULL; |
1da177e4 | 2089 | |
3b18152c | 2090 | if (cfq_cfqq_fifo_expire(cfqq)) |
1da177e4 | 2091 | return NULL; |
cb887411 JA |
2092 | |
2093 | cfq_mark_cfqq_fifo_expire(cfqq); | |
2094 | ||
89850f7e JA |
2095 | if (list_empty(&cfqq->fifo)) |
2096 | return NULL; | |
1da177e4 | 2097 | |
89850f7e | 2098 | rq = rq_entry_fifo(cfqq->fifo.next); |
30996f40 | 2099 | if (time_before(jiffies, rq_fifo_time(rq))) |
7b679138 | 2100 | rq = NULL; |
1da177e4 | 2101 | |
30996f40 | 2102 | cfq_log_cfqq(cfqq->cfqd, cfqq, "fifo=%p", rq); |
6d048f53 | 2103 | return rq; |
1da177e4 LT |
2104 | } |
2105 | ||
22e2c507 JA |
2106 | static inline int |
2107 | cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
2108 | { | |
2109 | const int base_rq = cfqd->cfq_slice_async_rq; | |
1da177e4 | 2110 | |
22e2c507 | 2111 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); |
1da177e4 | 2112 | |
b9f8ce05 | 2113 | return 2 * base_rq * (IOPRIO_BE_NR - cfqq->ioprio); |
1da177e4 LT |
2114 | } |
2115 | ||
df5fe3e8 JM |
2116 | /* |
2117 | * Must be called with the queue_lock held. | |
2118 | */ | |
2119 | static int cfqq_process_refs(struct cfq_queue *cfqq) | |
2120 | { | |
2121 | int process_refs, io_refs; | |
2122 | ||
2123 | io_refs = cfqq->allocated[READ] + cfqq->allocated[WRITE]; | |
30d7b944 | 2124 | process_refs = cfqq->ref - io_refs; |
df5fe3e8 JM |
2125 | BUG_ON(process_refs < 0); |
2126 | return process_refs; | |
2127 | } | |
2128 | ||
2129 | static void cfq_setup_merge(struct cfq_queue *cfqq, struct cfq_queue *new_cfqq) | |
2130 | { | |
e6c5bc73 | 2131 | int process_refs, new_process_refs; |
df5fe3e8 JM |
2132 | struct cfq_queue *__cfqq; |
2133 | ||
c10b61f0 JM |
2134 | /* |
2135 | * If there are no process references on the new_cfqq, then it is | |
2136 | * unsafe to follow the ->new_cfqq chain as other cfqq's in the | |
2137 | * chain may have dropped their last reference (not just their | |
2138 | * last process reference). | |
2139 | */ | |
2140 | if (!cfqq_process_refs(new_cfqq)) | |
2141 | return; | |
2142 | ||
df5fe3e8 JM |
2143 | /* Avoid a circular list and skip interim queue merges */ |
2144 | while ((__cfqq = new_cfqq->new_cfqq)) { | |
2145 | if (__cfqq == cfqq) | |
2146 | return; | |
2147 | new_cfqq = __cfqq; | |
2148 | } | |
2149 | ||
2150 | process_refs = cfqq_process_refs(cfqq); | |
c10b61f0 | 2151 | new_process_refs = cfqq_process_refs(new_cfqq); |
df5fe3e8 JM |
2152 | /* |
2153 | * If the process for the cfqq has gone away, there is no | |
2154 | * sense in merging the queues. | |
2155 | */ | |
c10b61f0 | 2156 | if (process_refs == 0 || new_process_refs == 0) |
df5fe3e8 JM |
2157 | return; |
2158 | ||
e6c5bc73 JM |
2159 | /* |
2160 | * Merge in the direction of the lesser amount of work. | |
2161 | */ | |
e6c5bc73 JM |
2162 | if (new_process_refs >= process_refs) { |
2163 | cfqq->new_cfqq = new_cfqq; | |
30d7b944 | 2164 | new_cfqq->ref += process_refs; |
e6c5bc73 JM |
2165 | } else { |
2166 | new_cfqq->new_cfqq = cfqq; | |
30d7b944 | 2167 | cfqq->ref += new_process_refs; |
e6c5bc73 | 2168 | } |
df5fe3e8 JM |
2169 | } |
2170 | ||
cdb16e8f | 2171 | static enum wl_type_t cfq_choose_wl(struct cfq_data *cfqd, |
65b32a57 | 2172 | struct cfq_group *cfqg, enum wl_prio_t prio) |
718eee05 CZ |
2173 | { |
2174 | struct cfq_queue *queue; | |
2175 | int i; | |
2176 | bool key_valid = false; | |
2177 | unsigned long lowest_key = 0; | |
2178 | enum wl_type_t cur_best = SYNC_NOIDLE_WORKLOAD; | |
2179 | ||
65b32a57 VG |
2180 | for (i = 0; i <= SYNC_WORKLOAD; ++i) { |
2181 | /* select the one with lowest rb_key */ | |
2182 | queue = cfq_rb_first(service_tree_for(cfqg, prio, i)); | |
718eee05 CZ |
2183 | if (queue && |
2184 | (!key_valid || time_before(queue->rb_key, lowest_key))) { | |
2185 | lowest_key = queue->rb_key; | |
2186 | cur_best = i; | |
2187 | key_valid = true; | |
2188 | } | |
2189 | } | |
2190 | ||
2191 | return cur_best; | |
2192 | } | |
2193 | ||
cdb16e8f | 2194 | static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg) |
718eee05 | 2195 | { |
718eee05 CZ |
2196 | unsigned slice; |
2197 | unsigned count; | |
cdb16e8f | 2198 | struct cfq_rb_root *st; |
58ff82f3 | 2199 | unsigned group_slice; |
e4ea0c16 | 2200 | enum wl_prio_t original_prio = cfqd->serving_prio; |
1fa8f6d6 | 2201 | |
718eee05 | 2202 | /* Choose next priority. RT > BE > IDLE */ |
58ff82f3 | 2203 | if (cfq_group_busy_queues_wl(RT_WORKLOAD, cfqd, cfqg)) |
718eee05 | 2204 | cfqd->serving_prio = RT_WORKLOAD; |
58ff82f3 | 2205 | else if (cfq_group_busy_queues_wl(BE_WORKLOAD, cfqd, cfqg)) |
718eee05 CZ |
2206 | cfqd->serving_prio = BE_WORKLOAD; |
2207 | else { | |
2208 | cfqd->serving_prio = IDLE_WORKLOAD; | |
2209 | cfqd->workload_expires = jiffies + 1; | |
2210 | return; | |
2211 | } | |
2212 | ||
e4ea0c16 SL |
2213 | if (original_prio != cfqd->serving_prio) |
2214 | goto new_workload; | |
2215 | ||
718eee05 CZ |
2216 | /* |
2217 | * For RT and BE, we have to choose also the type | |
2218 | * (SYNC, SYNC_NOIDLE, ASYNC), and to compute a workload | |
2219 | * expiration time | |
2220 | */ | |
65b32a57 | 2221 | st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type); |
cdb16e8f | 2222 | count = st->count; |
718eee05 CZ |
2223 | |
2224 | /* | |
65b32a57 | 2225 | * check workload expiration, and that we still have other queues ready |
718eee05 | 2226 | */ |
65b32a57 | 2227 | if (count && !time_after(jiffies, cfqd->workload_expires)) |
718eee05 CZ |
2228 | return; |
2229 | ||
e4ea0c16 | 2230 | new_workload: |
718eee05 CZ |
2231 | /* otherwise select new workload type */ |
2232 | cfqd->serving_type = | |
65b32a57 VG |
2233 | cfq_choose_wl(cfqd, cfqg, cfqd->serving_prio); |
2234 | st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type); | |
cdb16e8f | 2235 | count = st->count; |
718eee05 CZ |
2236 | |
2237 | /* | |
2238 | * the workload slice is computed as a fraction of target latency | |
2239 | * proportional to the number of queues in that workload, over | |
2240 | * all the queues in the same priority class | |
2241 | */ | |
58ff82f3 VG |
2242 | group_slice = cfq_group_slice(cfqd, cfqg); |
2243 | ||
2244 | slice = group_slice * count / | |
2245 | max_t(unsigned, cfqg->busy_queues_avg[cfqd->serving_prio], | |
2246 | cfq_group_busy_queues_wl(cfqd->serving_prio, cfqd, cfqg)); | |
718eee05 | 2247 | |
f26bd1f0 VG |
2248 | if (cfqd->serving_type == ASYNC_WORKLOAD) { |
2249 | unsigned int tmp; | |
2250 | ||
2251 | /* | |
2252 | * Async queues are currently system wide. Just taking | |
2253 | * proportion of queues with-in same group will lead to higher | |
2254 | * async ratio system wide as generally root group is going | |
2255 | * to have higher weight. A more accurate thing would be to | |
2256 | * calculate system wide asnc/sync ratio. | |
2257 | */ | |
2258 | tmp = cfq_target_latency * cfqg_busy_async_queues(cfqd, cfqg); | |
2259 | tmp = tmp/cfqd->busy_queues; | |
2260 | slice = min_t(unsigned, slice, tmp); | |
2261 | ||
718eee05 CZ |
2262 | /* async workload slice is scaled down according to |
2263 | * the sync/async slice ratio. */ | |
2264 | slice = slice * cfqd->cfq_slice[0] / cfqd->cfq_slice[1]; | |
f26bd1f0 | 2265 | } else |
718eee05 CZ |
2266 | /* sync workload slice is at least 2 * cfq_slice_idle */ |
2267 | slice = max(slice, 2 * cfqd->cfq_slice_idle); | |
2268 | ||
2269 | slice = max_t(unsigned, slice, CFQ_MIN_TT); | |
b1ffe737 | 2270 | cfq_log(cfqd, "workload slice:%d", slice); |
718eee05 CZ |
2271 | cfqd->workload_expires = jiffies + slice; |
2272 | } | |
2273 | ||
1fa8f6d6 VG |
2274 | static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd) |
2275 | { | |
2276 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
25bc6b07 | 2277 | struct cfq_group *cfqg; |
1fa8f6d6 VG |
2278 | |
2279 | if (RB_EMPTY_ROOT(&st->rb)) | |
2280 | return NULL; | |
25bc6b07 | 2281 | cfqg = cfq_rb_first_group(st); |
25bc6b07 VG |
2282 | update_min_vdisktime(st); |
2283 | return cfqg; | |
1fa8f6d6 VG |
2284 | } |
2285 | ||
cdb16e8f VG |
2286 | static void cfq_choose_cfqg(struct cfq_data *cfqd) |
2287 | { | |
1fa8f6d6 VG |
2288 | struct cfq_group *cfqg = cfq_get_next_cfqg(cfqd); |
2289 | ||
2290 | cfqd->serving_group = cfqg; | |
dae739eb VG |
2291 | |
2292 | /* Restore the workload type data */ | |
2293 | if (cfqg->saved_workload_slice) { | |
2294 | cfqd->workload_expires = jiffies + cfqg->saved_workload_slice; | |
2295 | cfqd->serving_type = cfqg->saved_workload; | |
2296 | cfqd->serving_prio = cfqg->saved_serving_prio; | |
66ae2919 GJ |
2297 | } else |
2298 | cfqd->workload_expires = jiffies - 1; | |
2299 | ||
1fa8f6d6 | 2300 | choose_service_tree(cfqd, cfqg); |
cdb16e8f VG |
2301 | } |
2302 | ||
22e2c507 | 2303 | /* |
498d3aa2 JA |
2304 | * Select a queue for service. If we have a current active queue, |
2305 | * check whether to continue servicing it, or retrieve and set a new one. | |
22e2c507 | 2306 | */ |
1b5ed5e1 | 2307 | static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) |
1da177e4 | 2308 | { |
a36e71f9 | 2309 | struct cfq_queue *cfqq, *new_cfqq = NULL; |
1da177e4 | 2310 | |
22e2c507 JA |
2311 | cfqq = cfqd->active_queue; |
2312 | if (!cfqq) | |
2313 | goto new_queue; | |
1da177e4 | 2314 | |
f04a6424 VG |
2315 | if (!cfqd->rq_queued) |
2316 | return NULL; | |
c244bb50 VG |
2317 | |
2318 | /* | |
2319 | * We were waiting for group to get backlogged. Expire the queue | |
2320 | */ | |
2321 | if (cfq_cfqq_wait_busy(cfqq) && !RB_EMPTY_ROOT(&cfqq->sort_list)) | |
2322 | goto expire; | |
2323 | ||
22e2c507 | 2324 | /* |
6d048f53 | 2325 | * The active queue has run out of time, expire it and select new. |
22e2c507 | 2326 | */ |
7667aa06 VG |
2327 | if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq)) { |
2328 | /* | |
2329 | * If slice had not expired at the completion of last request | |
2330 | * we might not have turned on wait_busy flag. Don't expire | |
2331 | * the queue yet. Allow the group to get backlogged. | |
2332 | * | |
2333 | * The very fact that we have used the slice, that means we | |
2334 | * have been idling all along on this queue and it should be | |
2335 | * ok to wait for this request to complete. | |
2336 | */ | |
82bbbf28 VG |
2337 | if (cfqq->cfqg->nr_cfqq == 1 && RB_EMPTY_ROOT(&cfqq->sort_list) |
2338 | && cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) { | |
2339 | cfqq = NULL; | |
7667aa06 | 2340 | goto keep_queue; |
82bbbf28 | 2341 | } else |
80bdf0c7 | 2342 | goto check_group_idle; |
7667aa06 | 2343 | } |
1da177e4 | 2344 | |
22e2c507 | 2345 | /* |
6d048f53 JA |
2346 | * The active queue has requests and isn't expired, allow it to |
2347 | * dispatch. | |
22e2c507 | 2348 | */ |
dd67d051 | 2349 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
22e2c507 | 2350 | goto keep_queue; |
6d048f53 | 2351 | |
a36e71f9 JA |
2352 | /* |
2353 | * If another queue has a request waiting within our mean seek | |
2354 | * distance, let it run. The expire code will check for close | |
2355 | * cooperators and put the close queue at the front of the service | |
df5fe3e8 | 2356 | * tree. If possible, merge the expiring queue with the new cfqq. |
a36e71f9 | 2357 | */ |
b3b6d040 | 2358 | new_cfqq = cfq_close_cooperator(cfqd, cfqq); |
df5fe3e8 JM |
2359 | if (new_cfqq) { |
2360 | if (!cfqq->new_cfqq) | |
2361 | cfq_setup_merge(cfqq, new_cfqq); | |
a36e71f9 | 2362 | goto expire; |
df5fe3e8 | 2363 | } |
a36e71f9 | 2364 | |
6d048f53 JA |
2365 | /* |
2366 | * No requests pending. If the active queue still has requests in | |
2367 | * flight or is idling for a new request, allow either of these | |
2368 | * conditions to happen (or time out) before selecting a new queue. | |
2369 | */ | |
80bdf0c7 VG |
2370 | if (timer_pending(&cfqd->idle_slice_timer)) { |
2371 | cfqq = NULL; | |
2372 | goto keep_queue; | |
2373 | } | |
2374 | ||
8e1ac665 SL |
2375 | /* |
2376 | * This is a deep seek queue, but the device is much faster than | |
2377 | * the queue can deliver, don't idle | |
2378 | **/ | |
2379 | if (CFQQ_SEEKY(cfqq) && cfq_cfqq_idle_window(cfqq) && | |
2380 | (cfq_cfqq_slice_new(cfqq) || | |
2381 | (cfqq->slice_end - jiffies > jiffies - cfqq->slice_start))) { | |
2382 | cfq_clear_cfqq_deep(cfqq); | |
2383 | cfq_clear_cfqq_idle_window(cfqq); | |
2384 | } | |
2385 | ||
80bdf0c7 VG |
2386 | if (cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) { |
2387 | cfqq = NULL; | |
2388 | goto keep_queue; | |
2389 | } | |
2390 | ||
2391 | /* | |
2392 | * If group idle is enabled and there are requests dispatched from | |
2393 | * this group, wait for requests to complete. | |
2394 | */ | |
2395 | check_group_idle: | |
7700fc4f SL |
2396 | if (cfqd->cfq_group_idle && cfqq->cfqg->nr_cfqq == 1 && |
2397 | cfqq->cfqg->dispatched && | |
2398 | !cfq_io_thinktime_big(cfqd, &cfqq->cfqg->ttime, true)) { | |
caaa5f9f JA |
2399 | cfqq = NULL; |
2400 | goto keep_queue; | |
22e2c507 JA |
2401 | } |
2402 | ||
3b18152c | 2403 | expire: |
e5ff082e | 2404 | cfq_slice_expired(cfqd, 0); |
3b18152c | 2405 | new_queue: |
718eee05 CZ |
2406 | /* |
2407 | * Current queue expired. Check if we have to switch to a new | |
2408 | * service tree | |
2409 | */ | |
2410 | if (!new_cfqq) | |
cdb16e8f | 2411 | cfq_choose_cfqg(cfqd); |
718eee05 | 2412 | |
a36e71f9 | 2413 | cfqq = cfq_set_active_queue(cfqd, new_cfqq); |
22e2c507 | 2414 | keep_queue: |
3b18152c | 2415 | return cfqq; |
22e2c507 JA |
2416 | } |
2417 | ||
febffd61 | 2418 | static int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq) |
d9e7620e JA |
2419 | { |
2420 | int dispatched = 0; | |
2421 | ||
2422 | while (cfqq->next_rq) { | |
2423 | cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq); | |
2424 | dispatched++; | |
2425 | } | |
2426 | ||
2427 | BUG_ON(!list_empty(&cfqq->fifo)); | |
f04a6424 VG |
2428 | |
2429 | /* By default cfqq is not expired if it is empty. Do it explicitly */ | |
e5ff082e | 2430 | __cfq_slice_expired(cfqq->cfqd, cfqq, 0); |
d9e7620e JA |
2431 | return dispatched; |
2432 | } | |
2433 | ||
498d3aa2 JA |
2434 | /* |
2435 | * Drain our current requests. Used for barriers and when switching | |
2436 | * io schedulers on-the-fly. | |
2437 | */ | |
d9e7620e | 2438 | static int cfq_forced_dispatch(struct cfq_data *cfqd) |
1b5ed5e1 | 2439 | { |
0871714e | 2440 | struct cfq_queue *cfqq; |
d9e7620e | 2441 | int dispatched = 0; |
cdb16e8f | 2442 | |
3440c49f | 2443 | /* Expire the timeslice of the current active queue first */ |
e5ff082e | 2444 | cfq_slice_expired(cfqd, 0); |
3440c49f DS |
2445 | while ((cfqq = cfq_get_next_queue_forced(cfqd)) != NULL) { |
2446 | __cfq_set_active_queue(cfqd, cfqq); | |
f04a6424 | 2447 | dispatched += __cfq_forced_dispatch_cfqq(cfqq); |
3440c49f | 2448 | } |
1b5ed5e1 | 2449 | |
1b5ed5e1 TH |
2450 | BUG_ON(cfqd->busy_queues); |
2451 | ||
6923715a | 2452 | cfq_log(cfqd, "forced_dispatch=%d", dispatched); |
1b5ed5e1 TH |
2453 | return dispatched; |
2454 | } | |
2455 | ||
abc3c744 SL |
2456 | static inline bool cfq_slice_used_soon(struct cfq_data *cfqd, |
2457 | struct cfq_queue *cfqq) | |
2458 | { | |
2459 | /* the queue hasn't finished any request, can't estimate */ | |
2460 | if (cfq_cfqq_slice_new(cfqq)) | |
c1e44756 | 2461 | return true; |
abc3c744 SL |
2462 | if (time_after(jiffies + cfqd->cfq_slice_idle * cfqq->dispatched, |
2463 | cfqq->slice_end)) | |
c1e44756 | 2464 | return true; |
abc3c744 | 2465 | |
c1e44756 | 2466 | return false; |
abc3c744 SL |
2467 | } |
2468 | ||
0b182d61 | 2469 | static bool cfq_may_dispatch(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
2f5cb738 | 2470 | { |
2f5cb738 | 2471 | unsigned int max_dispatch; |
22e2c507 | 2472 | |
5ad531db JA |
2473 | /* |
2474 | * Drain async requests before we start sync IO | |
2475 | */ | |
53c583d2 | 2476 | if (cfq_should_idle(cfqd, cfqq) && cfqd->rq_in_flight[BLK_RW_ASYNC]) |
0b182d61 | 2477 | return false; |
5ad531db | 2478 | |
2f5cb738 JA |
2479 | /* |
2480 | * If this is an async queue and we have sync IO in flight, let it wait | |
2481 | */ | |
53c583d2 | 2482 | if (cfqd->rq_in_flight[BLK_RW_SYNC] && !cfq_cfqq_sync(cfqq)) |
0b182d61 | 2483 | return false; |
2f5cb738 | 2484 | |
abc3c744 | 2485 | max_dispatch = max_t(unsigned int, cfqd->cfq_quantum / 2, 1); |
2f5cb738 JA |
2486 | if (cfq_class_idle(cfqq)) |
2487 | max_dispatch = 1; | |
b4878f24 | 2488 | |
2f5cb738 JA |
2489 | /* |
2490 | * Does this cfqq already have too much IO in flight? | |
2491 | */ | |
2492 | if (cfqq->dispatched >= max_dispatch) { | |
ef8a41df | 2493 | bool promote_sync = false; |
2f5cb738 JA |
2494 | /* |
2495 | * idle queue must always only have a single IO in flight | |
2496 | */ | |
3ed9a296 | 2497 | if (cfq_class_idle(cfqq)) |
0b182d61 | 2498 | return false; |
3ed9a296 | 2499 | |
ef8a41df | 2500 | /* |
c4ade94f LS |
2501 | * If there is only one sync queue |
2502 | * we can ignore async queue here and give the sync | |
ef8a41df SL |
2503 | * queue no dispatch limit. The reason is a sync queue can |
2504 | * preempt async queue, limiting the sync queue doesn't make | |
2505 | * sense. This is useful for aiostress test. | |
2506 | */ | |
c4ade94f LS |
2507 | if (cfq_cfqq_sync(cfqq) && cfqd->busy_sync_queues == 1) |
2508 | promote_sync = true; | |
ef8a41df | 2509 | |
2f5cb738 JA |
2510 | /* |
2511 | * We have other queues, don't allow more IO from this one | |
2512 | */ | |
ef8a41df SL |
2513 | if (cfqd->busy_queues > 1 && cfq_slice_used_soon(cfqd, cfqq) && |
2514 | !promote_sync) | |
0b182d61 | 2515 | return false; |
9ede209e | 2516 | |
365722bb | 2517 | /* |
474b18cc | 2518 | * Sole queue user, no limit |
365722bb | 2519 | */ |
ef8a41df | 2520 | if (cfqd->busy_queues == 1 || promote_sync) |
abc3c744 SL |
2521 | max_dispatch = -1; |
2522 | else | |
2523 | /* | |
2524 | * Normally we start throttling cfqq when cfq_quantum/2 | |
2525 | * requests have been dispatched. But we can drive | |
2526 | * deeper queue depths at the beginning of slice | |
2527 | * subjected to upper limit of cfq_quantum. | |
2528 | * */ | |
2529 | max_dispatch = cfqd->cfq_quantum; | |
8e296755 JA |
2530 | } |
2531 | ||
2532 | /* | |
2533 | * Async queues must wait a bit before being allowed dispatch. | |
2534 | * We also ramp up the dispatch depth gradually for async IO, | |
2535 | * based on the last sync IO we serviced | |
2536 | */ | |
963b72fc | 2537 | if (!cfq_cfqq_sync(cfqq) && cfqd->cfq_latency) { |
573412b2 | 2538 | unsigned long last_sync = jiffies - cfqd->last_delayed_sync; |
8e296755 | 2539 | unsigned int depth; |
365722bb | 2540 | |
61f0c1dc | 2541 | depth = last_sync / cfqd->cfq_slice[1]; |
e00c54c3 JA |
2542 | if (!depth && !cfqq->dispatched) |
2543 | depth = 1; | |
8e296755 JA |
2544 | if (depth < max_dispatch) |
2545 | max_dispatch = depth; | |
2f5cb738 | 2546 | } |
3ed9a296 | 2547 | |
0b182d61 JA |
2548 | /* |
2549 | * If we're below the current max, allow a dispatch | |
2550 | */ | |
2551 | return cfqq->dispatched < max_dispatch; | |
2552 | } | |
2553 | ||
2554 | /* | |
2555 | * Dispatch a request from cfqq, moving them to the request queue | |
2556 | * dispatch list. | |
2557 | */ | |
2558 | static bool cfq_dispatch_request(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
2559 | { | |
2560 | struct request *rq; | |
2561 | ||
2562 | BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list)); | |
2563 | ||
2564 | if (!cfq_may_dispatch(cfqd, cfqq)) | |
2565 | return false; | |
2566 | ||
2567 | /* | |
2568 | * follow expired path, else get first next available | |
2569 | */ | |
2570 | rq = cfq_check_fifo(cfqq); | |
2571 | if (!rq) | |
2572 | rq = cfqq->next_rq; | |
2573 | ||
2574 | /* | |
2575 | * insert request into driver dispatch list | |
2576 | */ | |
2577 | cfq_dispatch_insert(cfqd->queue, rq); | |
2578 | ||
2579 | if (!cfqd->active_cic) { | |
2580 | struct cfq_io_context *cic = RQ_CIC(rq); | |
2581 | ||
2582 | atomic_long_inc(&cic->ioc->refcount); | |
2583 | cfqd->active_cic = cic; | |
2584 | } | |
2585 | ||
2586 | return true; | |
2587 | } | |
2588 | ||
2589 | /* | |
2590 | * Find the cfqq that we need to service and move a request from that to the | |
2591 | * dispatch list | |
2592 | */ | |
2593 | static int cfq_dispatch_requests(struct request_queue *q, int force) | |
2594 | { | |
2595 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
2596 | struct cfq_queue *cfqq; | |
2597 | ||
2598 | if (!cfqd->busy_queues) | |
2599 | return 0; | |
2600 | ||
2601 | if (unlikely(force)) | |
2602 | return cfq_forced_dispatch(cfqd); | |
2603 | ||
2604 | cfqq = cfq_select_queue(cfqd); | |
2605 | if (!cfqq) | |
8e296755 JA |
2606 | return 0; |
2607 | ||
2f5cb738 | 2608 | /* |
0b182d61 | 2609 | * Dispatch a request from this cfqq, if it is allowed |
2f5cb738 | 2610 | */ |
0b182d61 JA |
2611 | if (!cfq_dispatch_request(cfqd, cfqq)) |
2612 | return 0; | |
2613 | ||
2f5cb738 | 2614 | cfqq->slice_dispatch++; |
b029195d | 2615 | cfq_clear_cfqq_must_dispatch(cfqq); |
22e2c507 | 2616 | |
2f5cb738 JA |
2617 | /* |
2618 | * expire an async queue immediately if it has used up its slice. idle | |
2619 | * queue always expire after 1 dispatch round. | |
2620 | */ | |
2621 | if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) && | |
2622 | cfqq->slice_dispatch >= cfq_prio_to_maxrq(cfqd, cfqq)) || | |
2623 | cfq_class_idle(cfqq))) { | |
2624 | cfqq->slice_end = jiffies + 1; | |
e5ff082e | 2625 | cfq_slice_expired(cfqd, 0); |
1da177e4 LT |
2626 | } |
2627 | ||
b217a903 | 2628 | cfq_log_cfqq(cfqd, cfqq, "dispatched a request"); |
2f5cb738 | 2629 | return 1; |
1da177e4 LT |
2630 | } |
2631 | ||
1da177e4 | 2632 | /* |
5e705374 JA |
2633 | * task holds one reference to the queue, dropped when task exits. each rq |
2634 | * in-flight on this queue also holds a reference, dropped when rq is freed. | |
1da177e4 | 2635 | * |
b1c35769 | 2636 | * Each cfq queue took a reference on the parent group. Drop it now. |
1da177e4 LT |
2637 | * queue lock must be held here. |
2638 | */ | |
2639 | static void cfq_put_queue(struct cfq_queue *cfqq) | |
2640 | { | |
22e2c507 | 2641 | struct cfq_data *cfqd = cfqq->cfqd; |
0bbfeb83 | 2642 | struct cfq_group *cfqg; |
22e2c507 | 2643 | |
30d7b944 | 2644 | BUG_ON(cfqq->ref <= 0); |
1da177e4 | 2645 | |
30d7b944 SL |
2646 | cfqq->ref--; |
2647 | if (cfqq->ref) | |
1da177e4 LT |
2648 | return; |
2649 | ||
7b679138 | 2650 | cfq_log_cfqq(cfqd, cfqq, "put_queue"); |
1da177e4 | 2651 | BUG_ON(rb_first(&cfqq->sort_list)); |
22e2c507 | 2652 | BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]); |
b1c35769 | 2653 | cfqg = cfqq->cfqg; |
1da177e4 | 2654 | |
28f95cbc | 2655 | if (unlikely(cfqd->active_queue == cfqq)) { |
e5ff082e | 2656 | __cfq_slice_expired(cfqd, cfqq, 0); |
23e018a1 | 2657 | cfq_schedule_dispatch(cfqd); |
28f95cbc | 2658 | } |
22e2c507 | 2659 | |
f04a6424 | 2660 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
1da177e4 | 2661 | kmem_cache_free(cfq_pool, cfqq); |
b1c35769 | 2662 | cfq_put_cfqg(cfqg); |
1da177e4 LT |
2663 | } |
2664 | ||
d6de8be7 | 2665 | /* |
5f45c695 | 2666 | * Call func for each cic attached to this ioc. |
d6de8be7 | 2667 | */ |
07416d29 | 2668 | static void |
5f45c695 JA |
2669 | call_for_each_cic(struct io_context *ioc, |
2670 | void (*func)(struct io_context *, struct cfq_io_context *)) | |
07416d29 JA |
2671 | { |
2672 | struct cfq_io_context *cic; | |
2673 | struct hlist_node *n; | |
2674 | ||
5f45c695 JA |
2675 | rcu_read_lock(); |
2676 | ||
07416d29 JA |
2677 | hlist_for_each_entry_rcu(cic, n, &ioc->cic_list, cic_list) |
2678 | func(ioc, cic); | |
07416d29 | 2679 | |
4ac845a2 | 2680 | rcu_read_unlock(); |
34e6bbf2 FC |
2681 | } |
2682 | ||
2683 | static void cfq_cic_free_rcu(struct rcu_head *head) | |
2684 | { | |
2685 | struct cfq_io_context *cic; | |
2686 | ||
2687 | cic = container_of(head, struct cfq_io_context, rcu_head); | |
2688 | ||
2689 | kmem_cache_free(cfq_ioc_pool, cic); | |
245b2e70 | 2690 | elv_ioc_count_dec(cfq_ioc_count); |
34e6bbf2 | 2691 | |
9a11b4ed JA |
2692 | if (ioc_gone) { |
2693 | /* | |
2694 | * CFQ scheduler is exiting, grab exit lock and check | |
2695 | * the pending io context count. If it hits zero, | |
2696 | * complete ioc_gone and set it back to NULL | |
2697 | */ | |
2698 | spin_lock(&ioc_gone_lock); | |
245b2e70 | 2699 | if (ioc_gone && !elv_ioc_count_read(cfq_ioc_count)) { |
9a11b4ed JA |
2700 | complete(ioc_gone); |
2701 | ioc_gone = NULL; | |
2702 | } | |
2703 | spin_unlock(&ioc_gone_lock); | |
2704 | } | |
34e6bbf2 | 2705 | } |
4ac845a2 | 2706 | |
34e6bbf2 FC |
2707 | static void cfq_cic_free(struct cfq_io_context *cic) |
2708 | { | |
2709 | call_rcu(&cic->rcu_head, cfq_cic_free_rcu); | |
4ac845a2 JA |
2710 | } |
2711 | ||
283287a5 | 2712 | static void cfq_release_cic(struct cfq_io_context *cic) |
4ac845a2 | 2713 | { |
283287a5 | 2714 | struct io_context *ioc = cic->ioc; |
bca4b914 | 2715 | unsigned long dead_key = (unsigned long) cic->key; |
4ac845a2 | 2716 | |
bca4b914 | 2717 | BUG_ON(!(dead_key & CIC_DEAD_KEY)); |
80b15c73 | 2718 | radix_tree_delete(&ioc->radix_root, dead_key >> CIC_DEAD_INDEX_SHIFT); |
ffc4e759 | 2719 | hlist_del_rcu(&cic->cic_list); |
34e6bbf2 | 2720 | cfq_cic_free(cic); |
4ac845a2 JA |
2721 | } |
2722 | ||
283287a5 TH |
2723 | static void cic_free_func(struct io_context *ioc, struct cfq_io_context *cic) |
2724 | { | |
2725 | unsigned long flags; | |
2726 | ||
2727 | spin_lock_irqsave(&ioc->lock, flags); | |
2728 | cfq_release_cic(cic); | |
2729 | spin_unlock_irqrestore(&ioc->lock, flags); | |
2730 | } | |
2731 | ||
d6de8be7 JA |
2732 | /* |
2733 | * Must be called with rcu_read_lock() held or preemption otherwise disabled. | |
2734 | * Only two callers of this - ->dtor() which is called with the rcu_read_lock(), | |
2735 | * and ->trim() which is called with the task lock held | |
2736 | */ | |
4ac845a2 JA |
2737 | static void cfq_free_io_context(struct io_context *ioc) |
2738 | { | |
4ac845a2 | 2739 | /* |
34e6bbf2 FC |
2740 | * ioc->refcount is zero here, or we are called from elv_unregister(), |
2741 | * so no more cic's are allowed to be linked into this ioc. So it | |
2742 | * should be ok to iterate over the known list, we will see all cic's | |
2743 | * since no new ones are added. | |
4ac845a2 | 2744 | */ |
5f45c695 | 2745 | call_for_each_cic(ioc, cic_free_func); |
1da177e4 LT |
2746 | } |
2747 | ||
d02a2c07 | 2748 | static void cfq_put_cooperator(struct cfq_queue *cfqq) |
1da177e4 | 2749 | { |
df5fe3e8 JM |
2750 | struct cfq_queue *__cfqq, *next; |
2751 | ||
df5fe3e8 JM |
2752 | /* |
2753 | * If this queue was scheduled to merge with another queue, be | |
2754 | * sure to drop the reference taken on that queue (and others in | |
2755 | * the merge chain). See cfq_setup_merge and cfq_merge_cfqqs. | |
2756 | */ | |
2757 | __cfqq = cfqq->new_cfqq; | |
2758 | while (__cfqq) { | |
2759 | if (__cfqq == cfqq) { | |
2760 | WARN(1, "cfqq->new_cfqq loop detected\n"); | |
2761 | break; | |
2762 | } | |
2763 | next = __cfqq->new_cfqq; | |
2764 | cfq_put_queue(__cfqq); | |
2765 | __cfqq = next; | |
2766 | } | |
d02a2c07 SL |
2767 | } |
2768 | ||
2769 | static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
2770 | { | |
2771 | if (unlikely(cfqq == cfqd->active_queue)) { | |
2772 | __cfq_slice_expired(cfqd, cfqq, 0); | |
2773 | cfq_schedule_dispatch(cfqd); | |
2774 | } | |
2775 | ||
2776 | cfq_put_cooperator(cfqq); | |
df5fe3e8 | 2777 | |
89850f7e JA |
2778 | cfq_put_queue(cfqq); |
2779 | } | |
22e2c507 | 2780 | |
283287a5 | 2781 | static void cfq_exit_cic(struct cfq_io_context *cic) |
89850f7e | 2782 | { |
283287a5 | 2783 | struct cfq_data *cfqd = cic_to_cfqd(cic); |
4faa3c81 FC |
2784 | struct io_context *ioc = cic->ioc; |
2785 | ||
fc46379d | 2786 | list_del_init(&cic->queue_list); |
4ac845a2 JA |
2787 | |
2788 | /* | |
bca4b914 | 2789 | * Make sure dead mark is seen for dead queues |
4ac845a2 | 2790 | */ |
fc46379d | 2791 | smp_wmb(); |
bca4b914 | 2792 | cic->key = cfqd_dead_key(cfqd); |
fc46379d | 2793 | |
3181faa8 | 2794 | rcu_read_lock(); |
9b50902d | 2795 | if (rcu_dereference(ioc->ioc_data) == cic) { |
3181faa8 | 2796 | rcu_read_unlock(); |
9b50902d | 2797 | spin_lock(&ioc->lock); |
4faa3c81 | 2798 | rcu_assign_pointer(ioc->ioc_data, NULL); |
9b50902d | 2799 | spin_unlock(&ioc->lock); |
3181faa8 SL |
2800 | } else |
2801 | rcu_read_unlock(); | |
4faa3c81 | 2802 | |
ff6657c6 JA |
2803 | if (cic->cfqq[BLK_RW_ASYNC]) { |
2804 | cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_ASYNC]); | |
2805 | cic->cfqq[BLK_RW_ASYNC] = NULL; | |
12a05732 AV |
2806 | } |
2807 | ||
ff6657c6 JA |
2808 | if (cic->cfqq[BLK_RW_SYNC]) { |
2809 | cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_SYNC]); | |
2810 | cic->cfqq[BLK_RW_SYNC] = NULL; | |
12a05732 | 2811 | } |
89850f7e JA |
2812 | } |
2813 | ||
4ac845a2 JA |
2814 | static void cfq_exit_single_io_context(struct io_context *ioc, |
2815 | struct cfq_io_context *cic) | |
89850f7e | 2816 | { |
bca4b914 | 2817 | struct cfq_data *cfqd = cic_to_cfqd(cic); |
89850f7e | 2818 | |
89850f7e | 2819 | if (cfqd) { |
165125e1 | 2820 | struct request_queue *q = cfqd->queue; |
4ac845a2 | 2821 | unsigned long flags; |
89850f7e | 2822 | |
4ac845a2 | 2823 | spin_lock_irqsave(q->queue_lock, flags); |
62c1fe9d JA |
2824 | |
2825 | /* | |
2826 | * Ensure we get a fresh copy of the ->key to prevent | |
2827 | * race between exiting task and queue | |
2828 | */ | |
2829 | smp_read_barrier_depends(); | |
bca4b914 | 2830 | if (cic->key == cfqd) |
283287a5 | 2831 | cfq_exit_cic(cic); |
62c1fe9d | 2832 | |
4ac845a2 | 2833 | spin_unlock_irqrestore(q->queue_lock, flags); |
89850f7e | 2834 | } |
1da177e4 LT |
2835 | } |
2836 | ||
498d3aa2 JA |
2837 | /* |
2838 | * The process that ioc belongs to has exited, we need to clean up | |
2839 | * and put the internal structures we have that belongs to that process. | |
2840 | */ | |
e2d74ac0 | 2841 | static void cfq_exit_io_context(struct io_context *ioc) |
1da177e4 | 2842 | { |
4ac845a2 | 2843 | call_for_each_cic(ioc, cfq_exit_single_io_context); |
1da177e4 LT |
2844 | } |
2845 | ||
22e2c507 | 2846 | static struct cfq_io_context * |
8267e268 | 2847 | cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
1da177e4 | 2848 | { |
b5deef90 | 2849 | struct cfq_io_context *cic; |
1da177e4 | 2850 | |
94f6030c CL |
2851 | cic = kmem_cache_alloc_node(cfq_ioc_pool, gfp_mask | __GFP_ZERO, |
2852 | cfqd->queue->node); | |
1da177e4 | 2853 | if (cic) { |
383cd721 | 2854 | cic->ttime.last_end_request = jiffies; |
553698f9 | 2855 | INIT_LIST_HEAD(&cic->queue_list); |
ffc4e759 | 2856 | INIT_HLIST_NODE(&cic->cic_list); |
22e2c507 JA |
2857 | cic->dtor = cfq_free_io_context; |
2858 | cic->exit = cfq_exit_io_context; | |
245b2e70 | 2859 | elv_ioc_count_inc(cfq_ioc_count); |
1da177e4 LT |
2860 | } |
2861 | ||
2862 | return cic; | |
2863 | } | |
2864 | ||
fd0928df | 2865 | static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc) |
22e2c507 JA |
2866 | { |
2867 | struct task_struct *tsk = current; | |
2868 | int ioprio_class; | |
2869 | ||
3b18152c | 2870 | if (!cfq_cfqq_prio_changed(cfqq)) |
22e2c507 JA |
2871 | return; |
2872 | ||
fd0928df | 2873 | ioprio_class = IOPRIO_PRIO_CLASS(ioc->ioprio); |
22e2c507 | 2874 | switch (ioprio_class) { |
fe094d98 JA |
2875 | default: |
2876 | printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class); | |
2877 | case IOPRIO_CLASS_NONE: | |
2878 | /* | |
6d63c275 | 2879 | * no prio set, inherit CPU scheduling settings |
fe094d98 JA |
2880 | */ |
2881 | cfqq->ioprio = task_nice_ioprio(tsk); | |
6d63c275 | 2882 | cfqq->ioprio_class = task_nice_ioclass(tsk); |
fe094d98 JA |
2883 | break; |
2884 | case IOPRIO_CLASS_RT: | |
2885 | cfqq->ioprio = task_ioprio(ioc); | |
2886 | cfqq->ioprio_class = IOPRIO_CLASS_RT; | |
2887 | break; | |
2888 | case IOPRIO_CLASS_BE: | |
2889 | cfqq->ioprio = task_ioprio(ioc); | |
2890 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
2891 | break; | |
2892 | case IOPRIO_CLASS_IDLE: | |
2893 | cfqq->ioprio_class = IOPRIO_CLASS_IDLE; | |
2894 | cfqq->ioprio = 7; | |
2895 | cfq_clear_cfqq_idle_window(cfqq); | |
2896 | break; | |
22e2c507 JA |
2897 | } |
2898 | ||
2899 | /* | |
2900 | * keep track of original prio settings in case we have to temporarily | |
2901 | * elevate the priority of this queue | |
2902 | */ | |
2903 | cfqq->org_ioprio = cfqq->ioprio; | |
3b18152c | 2904 | cfq_clear_cfqq_prio_changed(cfqq); |
22e2c507 JA |
2905 | } |
2906 | ||
dc86900e | 2907 | static void changed_ioprio(struct cfq_io_context *cic) |
22e2c507 | 2908 | { |
bca4b914 | 2909 | struct cfq_data *cfqd = cic_to_cfqd(cic); |
478a82b0 | 2910 | struct cfq_queue *cfqq; |
c1b707d2 | 2911 | unsigned long flags; |
35e6077c | 2912 | |
caaa5f9f JA |
2913 | if (unlikely(!cfqd)) |
2914 | return; | |
2915 | ||
c1b707d2 | 2916 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); |
caaa5f9f | 2917 | |
ff6657c6 | 2918 | cfqq = cic->cfqq[BLK_RW_ASYNC]; |
caaa5f9f JA |
2919 | if (cfqq) { |
2920 | struct cfq_queue *new_cfqq; | |
ff6657c6 JA |
2921 | new_cfqq = cfq_get_queue(cfqd, BLK_RW_ASYNC, cic->ioc, |
2922 | GFP_ATOMIC); | |
caaa5f9f | 2923 | if (new_cfqq) { |
ff6657c6 | 2924 | cic->cfqq[BLK_RW_ASYNC] = new_cfqq; |
caaa5f9f JA |
2925 | cfq_put_queue(cfqq); |
2926 | } | |
22e2c507 | 2927 | } |
caaa5f9f | 2928 | |
ff6657c6 | 2929 | cfqq = cic->cfqq[BLK_RW_SYNC]; |
caaa5f9f JA |
2930 | if (cfqq) |
2931 | cfq_mark_cfqq_prio_changed(cfqq); | |
2932 | ||
c1b707d2 | 2933 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); |
22e2c507 JA |
2934 | } |
2935 | ||
d5036d77 | 2936 | static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
a6151c3a | 2937 | pid_t pid, bool is_sync) |
d5036d77 JA |
2938 | { |
2939 | RB_CLEAR_NODE(&cfqq->rb_node); | |
2940 | RB_CLEAR_NODE(&cfqq->p_node); | |
2941 | INIT_LIST_HEAD(&cfqq->fifo); | |
2942 | ||
30d7b944 | 2943 | cfqq->ref = 0; |
d5036d77 JA |
2944 | cfqq->cfqd = cfqd; |
2945 | ||
2946 | cfq_mark_cfqq_prio_changed(cfqq); | |
2947 | ||
2948 | if (is_sync) { | |
2949 | if (!cfq_class_idle(cfqq)) | |
2950 | cfq_mark_cfqq_idle_window(cfqq); | |
2951 | cfq_mark_cfqq_sync(cfqq); | |
2952 | } | |
2953 | cfqq->pid = pid; | |
2954 | } | |
2955 | ||
24610333 | 2956 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
dc86900e | 2957 | static void changed_cgroup(struct cfq_io_context *cic) |
24610333 VG |
2958 | { |
2959 | struct cfq_queue *sync_cfqq = cic_to_cfqq(cic, 1); | |
bca4b914 | 2960 | struct cfq_data *cfqd = cic_to_cfqd(cic); |
24610333 VG |
2961 | unsigned long flags; |
2962 | struct request_queue *q; | |
2963 | ||
2964 | if (unlikely(!cfqd)) | |
2965 | return; | |
2966 | ||
2967 | q = cfqd->queue; | |
2968 | ||
2969 | spin_lock_irqsave(q->queue_lock, flags); | |
2970 | ||
2971 | if (sync_cfqq) { | |
2972 | /* | |
2973 | * Drop reference to sync queue. A new sync queue will be | |
2974 | * assigned in new group upon arrival of a fresh request. | |
2975 | */ | |
2976 | cfq_log_cfqq(cfqd, sync_cfqq, "changed cgroup"); | |
2977 | cic_set_cfqq(cic, NULL, 1); | |
2978 | cfq_put_queue(sync_cfqq); | |
2979 | } | |
2980 | ||
2981 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2982 | } | |
24610333 VG |
2983 | #endif /* CONFIG_CFQ_GROUP_IOSCHED */ |
2984 | ||
22e2c507 | 2985 | static struct cfq_queue * |
a6151c3a | 2986 | cfq_find_alloc_queue(struct cfq_data *cfqd, bool is_sync, |
fd0928df | 2987 | struct io_context *ioc, gfp_t gfp_mask) |
22e2c507 | 2988 | { |
22e2c507 | 2989 | struct cfq_queue *cfqq, *new_cfqq = NULL; |
91fac317 | 2990 | struct cfq_io_context *cic; |
cdb16e8f | 2991 | struct cfq_group *cfqg; |
22e2c507 JA |
2992 | |
2993 | retry: | |
3e59cf9d | 2994 | cfqg = cfq_get_cfqg(cfqd); |
4ac845a2 | 2995 | cic = cfq_cic_lookup(cfqd, ioc); |
91fac317 VT |
2996 | /* cic always exists here */ |
2997 | cfqq = cic_to_cfqq(cic, is_sync); | |
22e2c507 | 2998 | |
6118b70b JA |
2999 | /* |
3000 | * Always try a new alloc if we fell back to the OOM cfqq | |
3001 | * originally, since it should just be a temporary situation. | |
3002 | */ | |
3003 | if (!cfqq || cfqq == &cfqd->oom_cfqq) { | |
3004 | cfqq = NULL; | |
22e2c507 JA |
3005 | if (new_cfqq) { |
3006 | cfqq = new_cfqq; | |
3007 | new_cfqq = NULL; | |
3008 | } else if (gfp_mask & __GFP_WAIT) { | |
3009 | spin_unlock_irq(cfqd->queue->queue_lock); | |
94f6030c | 3010 | new_cfqq = kmem_cache_alloc_node(cfq_pool, |
6118b70b | 3011 | gfp_mask | __GFP_ZERO, |
94f6030c | 3012 | cfqd->queue->node); |
22e2c507 | 3013 | spin_lock_irq(cfqd->queue->queue_lock); |
6118b70b JA |
3014 | if (new_cfqq) |
3015 | goto retry; | |
22e2c507 | 3016 | } else { |
94f6030c CL |
3017 | cfqq = kmem_cache_alloc_node(cfq_pool, |
3018 | gfp_mask | __GFP_ZERO, | |
3019 | cfqd->queue->node); | |
22e2c507 JA |
3020 | } |
3021 | ||
6118b70b JA |
3022 | if (cfqq) { |
3023 | cfq_init_cfqq(cfqd, cfqq, current->pid, is_sync); | |
3024 | cfq_init_prio_data(cfqq, ioc); | |
cdb16e8f | 3025 | cfq_link_cfqq_cfqg(cfqq, cfqg); |
6118b70b JA |
3026 | cfq_log_cfqq(cfqd, cfqq, "alloced"); |
3027 | } else | |
3028 | cfqq = &cfqd->oom_cfqq; | |
22e2c507 JA |
3029 | } |
3030 | ||
3031 | if (new_cfqq) | |
3032 | kmem_cache_free(cfq_pool, new_cfqq); | |
3033 | ||
22e2c507 JA |
3034 | return cfqq; |
3035 | } | |
3036 | ||
c2dea2d1 VT |
3037 | static struct cfq_queue ** |
3038 | cfq_async_queue_prio(struct cfq_data *cfqd, int ioprio_class, int ioprio) | |
3039 | { | |
fe094d98 | 3040 | switch (ioprio_class) { |
c2dea2d1 VT |
3041 | case IOPRIO_CLASS_RT: |
3042 | return &cfqd->async_cfqq[0][ioprio]; | |
3043 | case IOPRIO_CLASS_BE: | |
3044 | return &cfqd->async_cfqq[1][ioprio]; | |
3045 | case IOPRIO_CLASS_IDLE: | |
3046 | return &cfqd->async_idle_cfqq; | |
3047 | default: | |
3048 | BUG(); | |
3049 | } | |
3050 | } | |
3051 | ||
15c31be4 | 3052 | static struct cfq_queue * |
a6151c3a | 3053 | cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct io_context *ioc, |
15c31be4 JA |
3054 | gfp_t gfp_mask) |
3055 | { | |
fd0928df JA |
3056 | const int ioprio = task_ioprio(ioc); |
3057 | const int ioprio_class = task_ioprio_class(ioc); | |
c2dea2d1 | 3058 | struct cfq_queue **async_cfqq = NULL; |
15c31be4 JA |
3059 | struct cfq_queue *cfqq = NULL; |
3060 | ||
c2dea2d1 VT |
3061 | if (!is_sync) { |
3062 | async_cfqq = cfq_async_queue_prio(cfqd, ioprio_class, ioprio); | |
3063 | cfqq = *async_cfqq; | |
3064 | } | |
3065 | ||
6118b70b | 3066 | if (!cfqq) |
fd0928df | 3067 | cfqq = cfq_find_alloc_queue(cfqd, is_sync, ioc, gfp_mask); |
15c31be4 JA |
3068 | |
3069 | /* | |
3070 | * pin the queue now that it's allocated, scheduler exit will prune it | |
3071 | */ | |
c2dea2d1 | 3072 | if (!is_sync && !(*async_cfqq)) { |
30d7b944 | 3073 | cfqq->ref++; |
c2dea2d1 | 3074 | *async_cfqq = cfqq; |
15c31be4 JA |
3075 | } |
3076 | ||
30d7b944 | 3077 | cfqq->ref++; |
15c31be4 JA |
3078 | return cfqq; |
3079 | } | |
3080 | ||
498d3aa2 JA |
3081 | /* |
3082 | * We drop cfq io contexts lazily, so we may find a dead one. | |
3083 | */ | |
dbecf3ab | 3084 | static void |
4ac845a2 JA |
3085 | cfq_drop_dead_cic(struct cfq_data *cfqd, struct io_context *ioc, |
3086 | struct cfq_io_context *cic) | |
dbecf3ab | 3087 | { |
4ac845a2 JA |
3088 | unsigned long flags; |
3089 | ||
fc46379d | 3090 | WARN_ON(!list_empty(&cic->queue_list)); |
bca4b914 | 3091 | BUG_ON(cic->key != cfqd_dead_key(cfqd)); |
597bc485 | 3092 | |
4ac845a2 JA |
3093 | spin_lock_irqsave(&ioc->lock, flags); |
3094 | ||
726e99ab SL |
3095 | BUG_ON(rcu_dereference_check(ioc->ioc_data, |
3096 | lockdep_is_held(&ioc->lock)) == cic); | |
597bc485 | 3097 | |
a73f730d | 3098 | radix_tree_delete(&ioc->radix_root, cfqd->queue->id); |
ffc4e759 | 3099 | hlist_del_rcu(&cic->cic_list); |
4ac845a2 JA |
3100 | spin_unlock_irqrestore(&ioc->lock, flags); |
3101 | ||
3102 | cfq_cic_free(cic); | |
dbecf3ab OH |
3103 | } |
3104 | ||
e2d74ac0 | 3105 | static struct cfq_io_context * |
4ac845a2 | 3106 | cfq_cic_lookup(struct cfq_data *cfqd, struct io_context *ioc) |
e2d74ac0 | 3107 | { |
e2d74ac0 | 3108 | struct cfq_io_context *cic; |
d6de8be7 | 3109 | unsigned long flags; |
e2d74ac0 | 3110 | |
91fac317 VT |
3111 | if (unlikely(!ioc)) |
3112 | return NULL; | |
3113 | ||
d6de8be7 JA |
3114 | rcu_read_lock(); |
3115 | ||
597bc485 JA |
3116 | /* |
3117 | * we maintain a last-hit cache, to avoid browsing over the tree | |
3118 | */ | |
4ac845a2 | 3119 | cic = rcu_dereference(ioc->ioc_data); |
d6de8be7 JA |
3120 | if (cic && cic->key == cfqd) { |
3121 | rcu_read_unlock(); | |
597bc485 | 3122 | return cic; |
d6de8be7 | 3123 | } |
597bc485 | 3124 | |
4ac845a2 | 3125 | do { |
a73f730d | 3126 | cic = radix_tree_lookup(&ioc->radix_root, cfqd->queue->id); |
4ac845a2 JA |
3127 | rcu_read_unlock(); |
3128 | if (!cic) | |
3129 | break; | |
bca4b914 | 3130 | if (unlikely(cic->key != cfqd)) { |
4ac845a2 | 3131 | cfq_drop_dead_cic(cfqd, ioc, cic); |
d6de8be7 | 3132 | rcu_read_lock(); |
4ac845a2 | 3133 | continue; |
dbecf3ab | 3134 | } |
e2d74ac0 | 3135 | |
d6de8be7 | 3136 | spin_lock_irqsave(&ioc->lock, flags); |
4ac845a2 | 3137 | rcu_assign_pointer(ioc->ioc_data, cic); |
d6de8be7 | 3138 | spin_unlock_irqrestore(&ioc->lock, flags); |
4ac845a2 JA |
3139 | break; |
3140 | } while (1); | |
e2d74ac0 | 3141 | |
4ac845a2 | 3142 | return cic; |
e2d74ac0 JA |
3143 | } |
3144 | ||
4ac845a2 JA |
3145 | /* |
3146 | * Add cic into ioc, using cfqd as the search key. This enables us to lookup | |
3147 | * the process specific cfq io context when entered from the block layer. | |
3148 | * Also adds the cic to a per-cfqd list, used when this queue is removed. | |
3149 | */ | |
febffd61 JA |
3150 | static int cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc, |
3151 | struct cfq_io_context *cic, gfp_t gfp_mask) | |
e2d74ac0 | 3152 | { |
0261d688 | 3153 | unsigned long flags; |
4ac845a2 | 3154 | int ret; |
e2d74ac0 | 3155 | |
4ac845a2 | 3156 | ret = radix_tree_preload(gfp_mask); |
283287a5 TH |
3157 | if (ret) |
3158 | goto out; | |
e2d74ac0 | 3159 | |
283287a5 TH |
3160 | cic->ioc = ioc; |
3161 | cic->key = cfqd; | |
3162 | cic->q = cfqd->queue; | |
3163 | ||
3164 | spin_lock_irqsave(&ioc->lock, flags); | |
3165 | ret = radix_tree_insert(&ioc->radix_root, cfqd->queue->id, cic); | |
3166 | if (!ret) | |
3167 | hlist_add_head_rcu(&cic->cic_list, &ioc->cic_list); | |
3168 | spin_unlock_irqrestore(&ioc->lock, flags); | |
e2d74ac0 | 3169 | |
283287a5 | 3170 | radix_tree_preload_end(); |
4ac845a2 | 3171 | |
283287a5 TH |
3172 | if (!ret) { |
3173 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
3174 | list_add(&cic->queue_list, &cfqd->cic_list); | |
3175 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
e2d74ac0 | 3176 | } |
283287a5 | 3177 | out: |
4ac845a2 JA |
3178 | if (ret) |
3179 | printk(KERN_ERR "cfq: cic link failed!\n"); | |
4ac845a2 | 3180 | return ret; |
e2d74ac0 JA |
3181 | } |
3182 | ||
1da177e4 LT |
3183 | /* |
3184 | * Setup general io context and cfq io context. There can be several cfq | |
3185 | * io contexts per general io context, if this process is doing io to more | |
e2d74ac0 | 3186 | * than one device managed by cfq. |
1da177e4 LT |
3187 | */ |
3188 | static struct cfq_io_context * | |
e2d74ac0 | 3189 | cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
1da177e4 | 3190 | { |
22e2c507 | 3191 | struct io_context *ioc = NULL; |
6e736be7 | 3192 | struct cfq_io_context *cic = NULL; |
1da177e4 | 3193 | |
22e2c507 | 3194 | might_sleep_if(gfp_mask & __GFP_WAIT); |
1da177e4 | 3195 | |
6e736be7 | 3196 | ioc = current_io_context(gfp_mask, cfqd->queue->node); |
1da177e4 | 3197 | if (!ioc) |
6e736be7 | 3198 | goto err; |
1da177e4 | 3199 | |
4ac845a2 | 3200 | cic = cfq_cic_lookup(cfqd, ioc); |
e2d74ac0 JA |
3201 | if (cic) |
3202 | goto out; | |
1da177e4 | 3203 | |
e2d74ac0 JA |
3204 | cic = cfq_alloc_io_context(cfqd, gfp_mask); |
3205 | if (cic == NULL) | |
3206 | goto err; | |
1da177e4 | 3207 | |
4ac845a2 | 3208 | if (cfq_cic_link(cfqd, ioc, cic, gfp_mask)) |
6e736be7 | 3209 | goto err; |
1da177e4 | 3210 | out: |
6e736be7 TH |
3211 | get_io_context(ioc); |
3212 | ||
dc86900e TH |
3213 | if (unlikely(cic->changed)) { |
3214 | if (test_and_clear_bit(CIC_IOPRIO_CHANGED, &cic->changed)) | |
3215 | changed_ioprio(cic); | |
24610333 | 3216 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
dc86900e TH |
3217 | if (test_and_clear_bit(CIC_CGROUP_CHANGED, &cic->changed)) |
3218 | changed_cgroup(cic); | |
24610333 | 3219 | #endif |
dc86900e TH |
3220 | } |
3221 | ||
1da177e4 LT |
3222 | return cic; |
3223 | err: | |
6e736be7 TH |
3224 | if (cic) |
3225 | cfq_cic_free(cic); | |
1da177e4 LT |
3226 | return NULL; |
3227 | } | |
3228 | ||
22e2c507 | 3229 | static void |
383cd721 | 3230 | __cfq_update_io_thinktime(struct cfq_ttime *ttime, unsigned long slice_idle) |
1da177e4 | 3231 | { |
383cd721 SL |
3232 | unsigned long elapsed = jiffies - ttime->last_end_request; |
3233 | elapsed = min(elapsed, 2UL * slice_idle); | |
db3b5848 | 3234 | |
383cd721 SL |
3235 | ttime->ttime_samples = (7*ttime->ttime_samples + 256) / 8; |
3236 | ttime->ttime_total = (7*ttime->ttime_total + 256*elapsed) / 8; | |
3237 | ttime->ttime_mean = (ttime->ttime_total + 128) / ttime->ttime_samples; | |
3238 | } | |
3239 | ||
3240 | static void | |
3241 | cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
3242 | struct cfq_io_context *cic) | |
3243 | { | |
f5f2b6ce | 3244 | if (cfq_cfqq_sync(cfqq)) { |
383cd721 | 3245 | __cfq_update_io_thinktime(&cic->ttime, cfqd->cfq_slice_idle); |
f5f2b6ce SL |
3246 | __cfq_update_io_thinktime(&cfqq->service_tree->ttime, |
3247 | cfqd->cfq_slice_idle); | |
3248 | } | |
7700fc4f SL |
3249 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
3250 | __cfq_update_io_thinktime(&cfqq->cfqg->ttime, cfqd->cfq_group_idle); | |
3251 | #endif | |
22e2c507 | 3252 | } |
1da177e4 | 3253 | |
206dc69b | 3254 | static void |
b2c18e1e | 3255 | cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
6d048f53 | 3256 | struct request *rq) |
206dc69b | 3257 | { |
3dde36dd | 3258 | sector_t sdist = 0; |
41647e7a | 3259 | sector_t n_sec = blk_rq_sectors(rq); |
3dde36dd CZ |
3260 | if (cfqq->last_request_pos) { |
3261 | if (cfqq->last_request_pos < blk_rq_pos(rq)) | |
3262 | sdist = blk_rq_pos(rq) - cfqq->last_request_pos; | |
3263 | else | |
3264 | sdist = cfqq->last_request_pos - blk_rq_pos(rq); | |
3265 | } | |
206dc69b | 3266 | |
3dde36dd | 3267 | cfqq->seek_history <<= 1; |
41647e7a CZ |
3268 | if (blk_queue_nonrot(cfqd->queue)) |
3269 | cfqq->seek_history |= (n_sec < CFQQ_SECT_THR_NONROT); | |
3270 | else | |
3271 | cfqq->seek_history |= (sdist > CFQQ_SEEK_THR); | |
206dc69b | 3272 | } |
1da177e4 | 3273 | |
22e2c507 JA |
3274 | /* |
3275 | * Disable idle window if the process thinks too long or seeks so much that | |
3276 | * it doesn't matter | |
3277 | */ | |
3278 | static void | |
3279 | cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
3280 | struct cfq_io_context *cic) | |
3281 | { | |
7b679138 | 3282 | int old_idle, enable_idle; |
1be92f2f | 3283 | |
0871714e JA |
3284 | /* |
3285 | * Don't idle for async or idle io prio class | |
3286 | */ | |
3287 | if (!cfq_cfqq_sync(cfqq) || cfq_class_idle(cfqq)) | |
1be92f2f JA |
3288 | return; |
3289 | ||
c265a7f4 | 3290 | enable_idle = old_idle = cfq_cfqq_idle_window(cfqq); |
1da177e4 | 3291 | |
76280aff CZ |
3292 | if (cfqq->queued[0] + cfqq->queued[1] >= 4) |
3293 | cfq_mark_cfqq_deep(cfqq); | |
3294 | ||
749ef9f8 CZ |
3295 | if (cfqq->next_rq && (cfqq->next_rq->cmd_flags & REQ_NOIDLE)) |
3296 | enable_idle = 0; | |
3297 | else if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle || | |
3dde36dd | 3298 | (!cfq_cfqq_deep(cfqq) && CFQQ_SEEKY(cfqq))) |
22e2c507 | 3299 | enable_idle = 0; |
383cd721 SL |
3300 | else if (sample_valid(cic->ttime.ttime_samples)) { |
3301 | if (cic->ttime.ttime_mean > cfqd->cfq_slice_idle) | |
22e2c507 JA |
3302 | enable_idle = 0; |
3303 | else | |
3304 | enable_idle = 1; | |
1da177e4 LT |
3305 | } |
3306 | ||
7b679138 JA |
3307 | if (old_idle != enable_idle) { |
3308 | cfq_log_cfqq(cfqd, cfqq, "idle=%d", enable_idle); | |
3309 | if (enable_idle) | |
3310 | cfq_mark_cfqq_idle_window(cfqq); | |
3311 | else | |
3312 | cfq_clear_cfqq_idle_window(cfqq); | |
3313 | } | |
22e2c507 | 3314 | } |
1da177e4 | 3315 | |
22e2c507 JA |
3316 | /* |
3317 | * Check if new_cfqq should preempt the currently active queue. Return 0 for | |
3318 | * no or if we aren't sure, a 1 will cause a preempt. | |
3319 | */ | |
a6151c3a | 3320 | static bool |
22e2c507 | 3321 | cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, |
5e705374 | 3322 | struct request *rq) |
22e2c507 | 3323 | { |
6d048f53 | 3324 | struct cfq_queue *cfqq; |
22e2c507 | 3325 | |
6d048f53 JA |
3326 | cfqq = cfqd->active_queue; |
3327 | if (!cfqq) | |
a6151c3a | 3328 | return false; |
22e2c507 | 3329 | |
6d048f53 | 3330 | if (cfq_class_idle(new_cfqq)) |
a6151c3a | 3331 | return false; |
22e2c507 JA |
3332 | |
3333 | if (cfq_class_idle(cfqq)) | |
a6151c3a | 3334 | return true; |
1e3335de | 3335 | |
875feb63 DS |
3336 | /* |
3337 | * Don't allow a non-RT request to preempt an ongoing RT cfqq timeslice. | |
3338 | */ | |
3339 | if (cfq_class_rt(cfqq) && !cfq_class_rt(new_cfqq)) | |
3340 | return false; | |
3341 | ||
374f84ac JA |
3342 | /* |
3343 | * if the new request is sync, but the currently running queue is | |
3344 | * not, let the sync request have priority. | |
3345 | */ | |
5e705374 | 3346 | if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq)) |
a6151c3a | 3347 | return true; |
1e3335de | 3348 | |
8682e1f1 VG |
3349 | if (new_cfqq->cfqg != cfqq->cfqg) |
3350 | return false; | |
3351 | ||
3352 | if (cfq_slice_used(cfqq)) | |
3353 | return true; | |
3354 | ||
3355 | /* Allow preemption only if we are idling on sync-noidle tree */ | |
3356 | if (cfqd->serving_type == SYNC_NOIDLE_WORKLOAD && | |
3357 | cfqq_type(new_cfqq) == SYNC_NOIDLE_WORKLOAD && | |
3358 | new_cfqq->service_tree->count == 2 && | |
3359 | RB_EMPTY_ROOT(&cfqq->sort_list)) | |
3360 | return true; | |
3361 | ||
b53d1ed7 JA |
3362 | /* |
3363 | * So both queues are sync. Let the new request get disk time if | |
3364 | * it's a metadata request and the current queue is doing regular IO. | |
3365 | */ | |
65299a3b | 3366 | if ((rq->cmd_flags & REQ_PRIO) && !cfqq->prio_pending) |
b53d1ed7 JA |
3367 | return true; |
3368 | ||
3a9a3f6c DS |
3369 | /* |
3370 | * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice. | |
3371 | */ | |
3372 | if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq)) | |
a6151c3a | 3373 | return true; |
3a9a3f6c | 3374 | |
d2d59e18 SL |
3375 | /* An idle queue should not be idle now for some reason */ |
3376 | if (RB_EMPTY_ROOT(&cfqq->sort_list) && !cfq_should_idle(cfqd, cfqq)) | |
3377 | return true; | |
3378 | ||
1e3335de | 3379 | if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq)) |
a6151c3a | 3380 | return false; |
1e3335de JA |
3381 | |
3382 | /* | |
3383 | * if this request is as-good as one we would expect from the | |
3384 | * current cfqq, let it preempt | |
3385 | */ | |
e9ce335d | 3386 | if (cfq_rq_close(cfqd, cfqq, rq)) |
a6151c3a | 3387 | return true; |
1e3335de | 3388 | |
a6151c3a | 3389 | return false; |
22e2c507 JA |
3390 | } |
3391 | ||
3392 | /* | |
3393 | * cfqq preempts the active queue. if we allowed preempt with no slice left, | |
3394 | * let it have half of its nominal slice. | |
3395 | */ | |
3396 | static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
3397 | { | |
f8ae6e3e SL |
3398 | struct cfq_queue *old_cfqq = cfqd->active_queue; |
3399 | ||
7b679138 | 3400 | cfq_log_cfqq(cfqd, cfqq, "preempt"); |
e5ff082e | 3401 | cfq_slice_expired(cfqd, 1); |
22e2c507 | 3402 | |
f8ae6e3e SL |
3403 | /* |
3404 | * workload type is changed, don't save slice, otherwise preempt | |
3405 | * doesn't happen | |
3406 | */ | |
3407 | if (cfqq_type(old_cfqq) != cfqq_type(cfqq)) | |
3408 | cfqq->cfqg->saved_workload_slice = 0; | |
3409 | ||
bf572256 JA |
3410 | /* |
3411 | * Put the new queue at the front of the of the current list, | |
3412 | * so we know that it will be selected next. | |
3413 | */ | |
3414 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); | |
edd75ffd JA |
3415 | |
3416 | cfq_service_tree_add(cfqd, cfqq, 1); | |
eda5e0c9 | 3417 | |
62a37f6b JT |
3418 | cfqq->slice_end = 0; |
3419 | cfq_mark_cfqq_slice_new(cfqq); | |
22e2c507 JA |
3420 | } |
3421 | ||
22e2c507 | 3422 | /* |
5e705374 | 3423 | * Called when a new fs request (rq) is added (to cfqq). Check if there's |
22e2c507 JA |
3424 | * something we should do about it |
3425 | */ | |
3426 | static void | |
5e705374 JA |
3427 | cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
3428 | struct request *rq) | |
22e2c507 | 3429 | { |
5e705374 | 3430 | struct cfq_io_context *cic = RQ_CIC(rq); |
12e9fddd | 3431 | |
45333d5a | 3432 | cfqd->rq_queued++; |
65299a3b CH |
3433 | if (rq->cmd_flags & REQ_PRIO) |
3434 | cfqq->prio_pending++; | |
374f84ac | 3435 | |
383cd721 | 3436 | cfq_update_io_thinktime(cfqd, cfqq, cic); |
b2c18e1e | 3437 | cfq_update_io_seektime(cfqd, cfqq, rq); |
9c2c38a1 JA |
3438 | cfq_update_idle_window(cfqd, cfqq, cic); |
3439 | ||
b2c18e1e | 3440 | cfqq->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq); |
22e2c507 JA |
3441 | |
3442 | if (cfqq == cfqd->active_queue) { | |
3443 | /* | |
b029195d JA |
3444 | * Remember that we saw a request from this process, but |
3445 | * don't start queuing just yet. Otherwise we risk seeing lots | |
3446 | * of tiny requests, because we disrupt the normal plugging | |
d6ceb25e JA |
3447 | * and merging. If the request is already larger than a single |
3448 | * page, let it rip immediately. For that case we assume that | |
2d870722 JA |
3449 | * merging is already done. Ditto for a busy system that |
3450 | * has other work pending, don't risk delaying until the | |
3451 | * idle timer unplug to continue working. | |
22e2c507 | 3452 | */ |
d6ceb25e | 3453 | if (cfq_cfqq_wait_request(cfqq)) { |
2d870722 JA |
3454 | if (blk_rq_bytes(rq) > PAGE_CACHE_SIZE || |
3455 | cfqd->busy_queues > 1) { | |
812df48d | 3456 | cfq_del_timer(cfqd, cfqq); |
554554f6 | 3457 | cfq_clear_cfqq_wait_request(cfqq); |
24ecfbe2 | 3458 | __blk_run_queue(cfqd->queue); |
a11cdaa7 | 3459 | } else { |
e98ef89b | 3460 | cfq_blkiocg_update_idle_time_stats( |
a11cdaa7 | 3461 | &cfqq->cfqg->blkg); |
bf791937 | 3462 | cfq_mark_cfqq_must_dispatch(cfqq); |
a11cdaa7 | 3463 | } |
d6ceb25e | 3464 | } |
5e705374 | 3465 | } else if (cfq_should_preempt(cfqd, cfqq, rq)) { |
22e2c507 JA |
3466 | /* |
3467 | * not the active queue - expire current slice if it is | |
3468 | * idle and has expired it's mean thinktime or this new queue | |
3a9a3f6c DS |
3469 | * has some old slice time left and is of higher priority or |
3470 | * this new queue is RT and the current one is BE | |
22e2c507 JA |
3471 | */ |
3472 | cfq_preempt_queue(cfqd, cfqq); | |
24ecfbe2 | 3473 | __blk_run_queue(cfqd->queue); |
22e2c507 | 3474 | } |
1da177e4 LT |
3475 | } |
3476 | ||
165125e1 | 3477 | static void cfq_insert_request(struct request_queue *q, struct request *rq) |
1da177e4 | 3478 | { |
b4878f24 | 3479 | struct cfq_data *cfqd = q->elevator->elevator_data; |
5e705374 | 3480 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 | 3481 | |
7b679138 | 3482 | cfq_log_cfqq(cfqd, cfqq, "insert_request"); |
fd0928df | 3483 | cfq_init_prio_data(cfqq, RQ_CIC(rq)->ioc); |
1da177e4 | 3484 | |
30996f40 | 3485 | rq_set_fifo_time(rq, jiffies + cfqd->cfq_fifo_expire[rq_is_sync(rq)]); |
22e2c507 | 3486 | list_add_tail(&rq->queuelist, &cfqq->fifo); |
aa6f6a3d | 3487 | cfq_add_rq_rb(rq); |
e98ef89b | 3488 | cfq_blkiocg_update_io_add_stats(&(RQ_CFQG(rq))->blkg, |
cdc1184c DS |
3489 | &cfqd->serving_group->blkg, rq_data_dir(rq), |
3490 | rq_is_sync(rq)); | |
5e705374 | 3491 | cfq_rq_enqueued(cfqd, cfqq, rq); |
1da177e4 LT |
3492 | } |
3493 | ||
45333d5a AC |
3494 | /* |
3495 | * Update hw_tag based on peak queue depth over 50 samples under | |
3496 | * sufficient load. | |
3497 | */ | |
3498 | static void cfq_update_hw_tag(struct cfq_data *cfqd) | |
3499 | { | |
1a1238a7 SL |
3500 | struct cfq_queue *cfqq = cfqd->active_queue; |
3501 | ||
53c583d2 CZ |
3502 | if (cfqd->rq_in_driver > cfqd->hw_tag_est_depth) |
3503 | cfqd->hw_tag_est_depth = cfqd->rq_in_driver; | |
e459dd08 CZ |
3504 | |
3505 | if (cfqd->hw_tag == 1) | |
3506 | return; | |
45333d5a AC |
3507 | |
3508 | if (cfqd->rq_queued <= CFQ_HW_QUEUE_MIN && | |
53c583d2 | 3509 | cfqd->rq_in_driver <= CFQ_HW_QUEUE_MIN) |
45333d5a AC |
3510 | return; |
3511 | ||
1a1238a7 SL |
3512 | /* |
3513 | * If active queue hasn't enough requests and can idle, cfq might not | |
3514 | * dispatch sufficient requests to hardware. Don't zero hw_tag in this | |
3515 | * case | |
3516 | */ | |
3517 | if (cfqq && cfq_cfqq_idle_window(cfqq) && | |
3518 | cfqq->dispatched + cfqq->queued[0] + cfqq->queued[1] < | |
53c583d2 | 3519 | CFQ_HW_QUEUE_MIN && cfqd->rq_in_driver < CFQ_HW_QUEUE_MIN) |
1a1238a7 SL |
3520 | return; |
3521 | ||
45333d5a AC |
3522 | if (cfqd->hw_tag_samples++ < 50) |
3523 | return; | |
3524 | ||
e459dd08 | 3525 | if (cfqd->hw_tag_est_depth >= CFQ_HW_QUEUE_MIN) |
45333d5a AC |
3526 | cfqd->hw_tag = 1; |
3527 | else | |
3528 | cfqd->hw_tag = 0; | |
45333d5a AC |
3529 | } |
3530 | ||
7667aa06 VG |
3531 | static bool cfq_should_wait_busy(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
3532 | { | |
3533 | struct cfq_io_context *cic = cfqd->active_cic; | |
3534 | ||
02a8f01b JT |
3535 | /* If the queue already has requests, don't wait */ |
3536 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) | |
3537 | return false; | |
3538 | ||
7667aa06 VG |
3539 | /* If there are other queues in the group, don't wait */ |
3540 | if (cfqq->cfqg->nr_cfqq > 1) | |
3541 | return false; | |
3542 | ||
7700fc4f SL |
3543 | /* the only queue in the group, but think time is big */ |
3544 | if (cfq_io_thinktime_big(cfqd, &cfqq->cfqg->ttime, true)) | |
3545 | return false; | |
3546 | ||
7667aa06 VG |
3547 | if (cfq_slice_used(cfqq)) |
3548 | return true; | |
3549 | ||
3550 | /* if slice left is less than think time, wait busy */ | |
383cd721 SL |
3551 | if (cic && sample_valid(cic->ttime.ttime_samples) |
3552 | && (cfqq->slice_end - jiffies < cic->ttime.ttime_mean)) | |
7667aa06 VG |
3553 | return true; |
3554 | ||
3555 | /* | |
3556 | * If think times is less than a jiffy than ttime_mean=0 and above | |
3557 | * will not be true. It might happen that slice has not expired yet | |
3558 | * but will expire soon (4-5 ns) during select_queue(). To cover the | |
3559 | * case where think time is less than a jiffy, mark the queue wait | |
3560 | * busy if only 1 jiffy is left in the slice. | |
3561 | */ | |
3562 | if (cfqq->slice_end - jiffies == 1) | |
3563 | return true; | |
3564 | ||
3565 | return false; | |
3566 | } | |
3567 | ||
165125e1 | 3568 | static void cfq_completed_request(struct request_queue *q, struct request *rq) |
1da177e4 | 3569 | { |
5e705374 | 3570 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
b4878f24 | 3571 | struct cfq_data *cfqd = cfqq->cfqd; |
5380a101 | 3572 | const int sync = rq_is_sync(rq); |
b4878f24 | 3573 | unsigned long now; |
1da177e4 | 3574 | |
b4878f24 | 3575 | now = jiffies; |
33659ebb CH |
3576 | cfq_log_cfqq(cfqd, cfqq, "complete rqnoidle %d", |
3577 | !!(rq->cmd_flags & REQ_NOIDLE)); | |
1da177e4 | 3578 | |
45333d5a AC |
3579 | cfq_update_hw_tag(cfqd); |
3580 | ||
53c583d2 | 3581 | WARN_ON(!cfqd->rq_in_driver); |
6d048f53 | 3582 | WARN_ON(!cfqq->dispatched); |
53c583d2 | 3583 | cfqd->rq_in_driver--; |
6d048f53 | 3584 | cfqq->dispatched--; |
80bdf0c7 | 3585 | (RQ_CFQG(rq))->dispatched--; |
e98ef89b VG |
3586 | cfq_blkiocg_update_completion_stats(&cfqq->cfqg->blkg, |
3587 | rq_start_time_ns(rq), rq_io_start_time_ns(rq), | |
3588 | rq_data_dir(rq), rq_is_sync(rq)); | |
1da177e4 | 3589 | |
53c583d2 | 3590 | cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]--; |
3ed9a296 | 3591 | |
365722bb | 3592 | if (sync) { |
f5f2b6ce SL |
3593 | struct cfq_rb_root *service_tree; |
3594 | ||
383cd721 | 3595 | RQ_CIC(rq)->ttime.last_end_request = now; |
f5f2b6ce SL |
3596 | |
3597 | if (cfq_cfqq_on_rr(cfqq)) | |
3598 | service_tree = cfqq->service_tree; | |
3599 | else | |
3600 | service_tree = service_tree_for(cfqq->cfqg, | |
3601 | cfqq_prio(cfqq), cfqq_type(cfqq)); | |
3602 | service_tree->ttime.last_end_request = now; | |
573412b2 CZ |
3603 | if (!time_after(rq->start_time + cfqd->cfq_fifo_expire[1], now)) |
3604 | cfqd->last_delayed_sync = now; | |
365722bb | 3605 | } |
caaa5f9f | 3606 | |
7700fc4f SL |
3607 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
3608 | cfqq->cfqg->ttime.last_end_request = now; | |
3609 | #endif | |
3610 | ||
caaa5f9f JA |
3611 | /* |
3612 | * If this is the active queue, check if it needs to be expired, | |
3613 | * or if we want to idle in case it has no pending requests. | |
3614 | */ | |
3615 | if (cfqd->active_queue == cfqq) { | |
a36e71f9 JA |
3616 | const bool cfqq_empty = RB_EMPTY_ROOT(&cfqq->sort_list); |
3617 | ||
44f7c160 JA |
3618 | if (cfq_cfqq_slice_new(cfqq)) { |
3619 | cfq_set_prio_slice(cfqd, cfqq); | |
3620 | cfq_clear_cfqq_slice_new(cfqq); | |
3621 | } | |
f75edf2d VG |
3622 | |
3623 | /* | |
7667aa06 VG |
3624 | * Should we wait for next request to come in before we expire |
3625 | * the queue. | |
f75edf2d | 3626 | */ |
7667aa06 | 3627 | if (cfq_should_wait_busy(cfqd, cfqq)) { |
80bdf0c7 VG |
3628 | unsigned long extend_sl = cfqd->cfq_slice_idle; |
3629 | if (!cfqd->cfq_slice_idle) | |
3630 | extend_sl = cfqd->cfq_group_idle; | |
3631 | cfqq->slice_end = jiffies + extend_sl; | |
f75edf2d | 3632 | cfq_mark_cfqq_wait_busy(cfqq); |
b1ffe737 | 3633 | cfq_log_cfqq(cfqd, cfqq, "will busy wait"); |
f75edf2d VG |
3634 | } |
3635 | ||
a36e71f9 | 3636 | /* |
8e550632 CZ |
3637 | * Idling is not enabled on: |
3638 | * - expired queues | |
3639 | * - idle-priority queues | |
3640 | * - async queues | |
3641 | * - queues with still some requests queued | |
3642 | * - when there is a close cooperator | |
a36e71f9 | 3643 | */ |
0871714e | 3644 | if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq)) |
e5ff082e | 3645 | cfq_slice_expired(cfqd, 1); |
8e550632 CZ |
3646 | else if (sync && cfqq_empty && |
3647 | !cfq_close_cooperator(cfqd, cfqq)) { | |
749ef9f8 | 3648 | cfq_arm_slice_timer(cfqd); |
8e550632 | 3649 | } |
caaa5f9f | 3650 | } |
6d048f53 | 3651 | |
53c583d2 | 3652 | if (!cfqd->rq_in_driver) |
23e018a1 | 3653 | cfq_schedule_dispatch(cfqd); |
1da177e4 LT |
3654 | } |
3655 | ||
89850f7e | 3656 | static inline int __cfq_may_queue(struct cfq_queue *cfqq) |
22e2c507 | 3657 | { |
1b379d8d | 3658 | if (cfq_cfqq_wait_request(cfqq) && !cfq_cfqq_must_alloc_slice(cfqq)) { |
3b18152c | 3659 | cfq_mark_cfqq_must_alloc_slice(cfqq); |
22e2c507 | 3660 | return ELV_MQUEUE_MUST; |
3b18152c | 3661 | } |
1da177e4 | 3662 | |
22e2c507 | 3663 | return ELV_MQUEUE_MAY; |
22e2c507 JA |
3664 | } |
3665 | ||
165125e1 | 3666 | static int cfq_may_queue(struct request_queue *q, int rw) |
22e2c507 JA |
3667 | { |
3668 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
3669 | struct task_struct *tsk = current; | |
91fac317 | 3670 | struct cfq_io_context *cic; |
22e2c507 JA |
3671 | struct cfq_queue *cfqq; |
3672 | ||
3673 | /* | |
3674 | * don't force setup of a queue from here, as a call to may_queue | |
3675 | * does not necessarily imply that a request actually will be queued. | |
3676 | * so just lookup a possibly existing queue, or return 'may queue' | |
3677 | * if that fails | |
3678 | */ | |
4ac845a2 | 3679 | cic = cfq_cic_lookup(cfqd, tsk->io_context); |
91fac317 VT |
3680 | if (!cic) |
3681 | return ELV_MQUEUE_MAY; | |
3682 | ||
b0b78f81 | 3683 | cfqq = cic_to_cfqq(cic, rw_is_sync(rw)); |
22e2c507 | 3684 | if (cfqq) { |
fd0928df | 3685 | cfq_init_prio_data(cfqq, cic->ioc); |
22e2c507 | 3686 | |
89850f7e | 3687 | return __cfq_may_queue(cfqq); |
22e2c507 JA |
3688 | } |
3689 | ||
3690 | return ELV_MQUEUE_MAY; | |
1da177e4 LT |
3691 | } |
3692 | ||
1da177e4 LT |
3693 | /* |
3694 | * queue lock held here | |
3695 | */ | |
bb37b94c | 3696 | static void cfq_put_request(struct request *rq) |
1da177e4 | 3697 | { |
5e705374 | 3698 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
1da177e4 | 3699 | |
5e705374 | 3700 | if (cfqq) { |
22e2c507 | 3701 | const int rw = rq_data_dir(rq); |
1da177e4 | 3702 | |
22e2c507 JA |
3703 | BUG_ON(!cfqq->allocated[rw]); |
3704 | cfqq->allocated[rw]--; | |
1da177e4 | 3705 | |
5e705374 | 3706 | put_io_context(RQ_CIC(rq)->ioc); |
1da177e4 | 3707 | |
c186794d MS |
3708 | rq->elevator_private[0] = NULL; |
3709 | rq->elevator_private[1] = NULL; | |
1da177e4 | 3710 | |
7f1dc8a2 VG |
3711 | /* Put down rq reference on cfqg */ |
3712 | cfq_put_cfqg(RQ_CFQG(rq)); | |
c186794d | 3713 | rq->elevator_private[2] = NULL; |
7f1dc8a2 | 3714 | |
1da177e4 LT |
3715 | cfq_put_queue(cfqq); |
3716 | } | |
3717 | } | |
3718 | ||
df5fe3e8 JM |
3719 | static struct cfq_queue * |
3720 | cfq_merge_cfqqs(struct cfq_data *cfqd, struct cfq_io_context *cic, | |
3721 | struct cfq_queue *cfqq) | |
3722 | { | |
3723 | cfq_log_cfqq(cfqd, cfqq, "merging with queue %p", cfqq->new_cfqq); | |
3724 | cic_set_cfqq(cic, cfqq->new_cfqq, 1); | |
b3b6d040 | 3725 | cfq_mark_cfqq_coop(cfqq->new_cfqq); |
df5fe3e8 JM |
3726 | cfq_put_queue(cfqq); |
3727 | return cic_to_cfqq(cic, 1); | |
3728 | } | |
3729 | ||
e6c5bc73 JM |
3730 | /* |
3731 | * Returns NULL if a new cfqq should be allocated, or the old cfqq if this | |
3732 | * was the last process referring to said cfqq. | |
3733 | */ | |
3734 | static struct cfq_queue * | |
3735 | split_cfqq(struct cfq_io_context *cic, struct cfq_queue *cfqq) | |
3736 | { | |
3737 | if (cfqq_process_refs(cfqq) == 1) { | |
e6c5bc73 JM |
3738 | cfqq->pid = current->pid; |
3739 | cfq_clear_cfqq_coop(cfqq); | |
ae54abed | 3740 | cfq_clear_cfqq_split_coop(cfqq); |
e6c5bc73 JM |
3741 | return cfqq; |
3742 | } | |
3743 | ||
3744 | cic_set_cfqq(cic, NULL, 1); | |
d02a2c07 SL |
3745 | |
3746 | cfq_put_cooperator(cfqq); | |
3747 | ||
e6c5bc73 JM |
3748 | cfq_put_queue(cfqq); |
3749 | return NULL; | |
3750 | } | |
1da177e4 | 3751 | /* |
22e2c507 | 3752 | * Allocate cfq data structures associated with this request. |
1da177e4 | 3753 | */ |
22e2c507 | 3754 | static int |
165125e1 | 3755 | cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask) |
1da177e4 LT |
3756 | { |
3757 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
3758 | struct cfq_io_context *cic; | |
3759 | const int rw = rq_data_dir(rq); | |
a6151c3a | 3760 | const bool is_sync = rq_is_sync(rq); |
22e2c507 | 3761 | struct cfq_queue *cfqq; |
1da177e4 LT |
3762 | unsigned long flags; |
3763 | ||
3764 | might_sleep_if(gfp_mask & __GFP_WAIT); | |
3765 | ||
e2d74ac0 | 3766 | cic = cfq_get_io_context(cfqd, gfp_mask); |
22e2c507 | 3767 | |
1da177e4 LT |
3768 | spin_lock_irqsave(q->queue_lock, flags); |
3769 | ||
22e2c507 JA |
3770 | if (!cic) |
3771 | goto queue_fail; | |
3772 | ||
e6c5bc73 | 3773 | new_queue: |
91fac317 | 3774 | cfqq = cic_to_cfqq(cic, is_sync); |
32f2e807 | 3775 | if (!cfqq || cfqq == &cfqd->oom_cfqq) { |
fd0928df | 3776 | cfqq = cfq_get_queue(cfqd, is_sync, cic->ioc, gfp_mask); |
91fac317 | 3777 | cic_set_cfqq(cic, cfqq, is_sync); |
df5fe3e8 | 3778 | } else { |
e6c5bc73 JM |
3779 | /* |
3780 | * If the queue was seeky for too long, break it apart. | |
3781 | */ | |
ae54abed | 3782 | if (cfq_cfqq_coop(cfqq) && cfq_cfqq_split_coop(cfqq)) { |
e6c5bc73 JM |
3783 | cfq_log_cfqq(cfqd, cfqq, "breaking apart cfqq"); |
3784 | cfqq = split_cfqq(cic, cfqq); | |
3785 | if (!cfqq) | |
3786 | goto new_queue; | |
3787 | } | |
3788 | ||
df5fe3e8 JM |
3789 | /* |
3790 | * Check to see if this queue is scheduled to merge with | |
3791 | * another, closely cooperating queue. The merging of | |
3792 | * queues happens here as it must be done in process context. | |
3793 | * The reference on new_cfqq was taken in merge_cfqqs. | |
3794 | */ | |
3795 | if (cfqq->new_cfqq) | |
3796 | cfqq = cfq_merge_cfqqs(cfqd, cic, cfqq); | |
91fac317 | 3797 | } |
1da177e4 LT |
3798 | |
3799 | cfqq->allocated[rw]++; | |
1da177e4 | 3800 | |
6fae9c25 | 3801 | cfqq->ref++; |
c186794d MS |
3802 | rq->elevator_private[0] = cic; |
3803 | rq->elevator_private[1] = cfqq; | |
3804 | rq->elevator_private[2] = cfq_ref_get_cfqg(cfqq->cfqg); | |
93803e01 | 3805 | spin_unlock_irqrestore(q->queue_lock, flags); |
5e705374 | 3806 | return 0; |
1da177e4 | 3807 | |
22e2c507 | 3808 | queue_fail: |
23e018a1 | 3809 | cfq_schedule_dispatch(cfqd); |
1da177e4 | 3810 | spin_unlock_irqrestore(q->queue_lock, flags); |
7b679138 | 3811 | cfq_log(cfqd, "set_request fail"); |
1da177e4 LT |
3812 | return 1; |
3813 | } | |
3814 | ||
65f27f38 | 3815 | static void cfq_kick_queue(struct work_struct *work) |
22e2c507 | 3816 | { |
65f27f38 | 3817 | struct cfq_data *cfqd = |
23e018a1 | 3818 | container_of(work, struct cfq_data, unplug_work); |
165125e1 | 3819 | struct request_queue *q = cfqd->queue; |
22e2c507 | 3820 | |
40bb54d1 | 3821 | spin_lock_irq(q->queue_lock); |
24ecfbe2 | 3822 | __blk_run_queue(cfqd->queue); |
40bb54d1 | 3823 | spin_unlock_irq(q->queue_lock); |
22e2c507 JA |
3824 | } |
3825 | ||
3826 | /* | |
3827 | * Timer running if the active_queue is currently idling inside its time slice | |
3828 | */ | |
3829 | static void cfq_idle_slice_timer(unsigned long data) | |
3830 | { | |
3831 | struct cfq_data *cfqd = (struct cfq_data *) data; | |
3832 | struct cfq_queue *cfqq; | |
3833 | unsigned long flags; | |
3c6bd2f8 | 3834 | int timed_out = 1; |
22e2c507 | 3835 | |
7b679138 JA |
3836 | cfq_log(cfqd, "idle timer fired"); |
3837 | ||
22e2c507 JA |
3838 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); |
3839 | ||
fe094d98 JA |
3840 | cfqq = cfqd->active_queue; |
3841 | if (cfqq) { | |
3c6bd2f8 JA |
3842 | timed_out = 0; |
3843 | ||
b029195d JA |
3844 | /* |
3845 | * We saw a request before the queue expired, let it through | |
3846 | */ | |
3847 | if (cfq_cfqq_must_dispatch(cfqq)) | |
3848 | goto out_kick; | |
3849 | ||
22e2c507 JA |
3850 | /* |
3851 | * expired | |
3852 | */ | |
44f7c160 | 3853 | if (cfq_slice_used(cfqq)) |
22e2c507 JA |
3854 | goto expire; |
3855 | ||
3856 | /* | |
3857 | * only expire and reinvoke request handler, if there are | |
3858 | * other queues with pending requests | |
3859 | */ | |
caaa5f9f | 3860 | if (!cfqd->busy_queues) |
22e2c507 | 3861 | goto out_cont; |
22e2c507 JA |
3862 | |
3863 | /* | |
3864 | * not expired and it has a request pending, let it dispatch | |
3865 | */ | |
75e50984 | 3866 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
22e2c507 | 3867 | goto out_kick; |
76280aff CZ |
3868 | |
3869 | /* | |
3870 | * Queue depth flag is reset only when the idle didn't succeed | |
3871 | */ | |
3872 | cfq_clear_cfqq_deep(cfqq); | |
22e2c507 JA |
3873 | } |
3874 | expire: | |
e5ff082e | 3875 | cfq_slice_expired(cfqd, timed_out); |
22e2c507 | 3876 | out_kick: |
23e018a1 | 3877 | cfq_schedule_dispatch(cfqd); |
22e2c507 JA |
3878 | out_cont: |
3879 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
3880 | } | |
3881 | ||
3b18152c JA |
3882 | static void cfq_shutdown_timer_wq(struct cfq_data *cfqd) |
3883 | { | |
3884 | del_timer_sync(&cfqd->idle_slice_timer); | |
23e018a1 | 3885 | cancel_work_sync(&cfqd->unplug_work); |
3b18152c | 3886 | } |
22e2c507 | 3887 | |
c2dea2d1 VT |
3888 | static void cfq_put_async_queues(struct cfq_data *cfqd) |
3889 | { | |
3890 | int i; | |
3891 | ||
3892 | for (i = 0; i < IOPRIO_BE_NR; i++) { | |
3893 | if (cfqd->async_cfqq[0][i]) | |
3894 | cfq_put_queue(cfqd->async_cfqq[0][i]); | |
3895 | if (cfqd->async_cfqq[1][i]) | |
3896 | cfq_put_queue(cfqd->async_cfqq[1][i]); | |
c2dea2d1 | 3897 | } |
2389d1ef ON |
3898 | |
3899 | if (cfqd->async_idle_cfqq) | |
3900 | cfq_put_queue(cfqd->async_idle_cfqq); | |
c2dea2d1 VT |
3901 | } |
3902 | ||
b374d18a | 3903 | static void cfq_exit_queue(struct elevator_queue *e) |
1da177e4 | 3904 | { |
22e2c507 | 3905 | struct cfq_data *cfqd = e->elevator_data; |
165125e1 | 3906 | struct request_queue *q = cfqd->queue; |
56edf7d7 | 3907 | bool wait = false; |
22e2c507 | 3908 | |
3b18152c | 3909 | cfq_shutdown_timer_wq(cfqd); |
e2d74ac0 | 3910 | |
d9ff4187 | 3911 | spin_lock_irq(q->queue_lock); |
e2d74ac0 | 3912 | |
d9ff4187 | 3913 | if (cfqd->active_queue) |
e5ff082e | 3914 | __cfq_slice_expired(cfqd, cfqd->active_queue, 0); |
e2d74ac0 JA |
3915 | |
3916 | while (!list_empty(&cfqd->cic_list)) { | |
d9ff4187 AV |
3917 | struct cfq_io_context *cic = list_entry(cfqd->cic_list.next, |
3918 | struct cfq_io_context, | |
3919 | queue_list); | |
89850f7e | 3920 | |
283287a5 | 3921 | cfq_exit_cic(cic); |
d9ff4187 | 3922 | } |
e2d74ac0 | 3923 | |
c2dea2d1 | 3924 | cfq_put_async_queues(cfqd); |
b1c35769 | 3925 | cfq_release_cfq_groups(cfqd); |
56edf7d7 VG |
3926 | |
3927 | /* | |
3928 | * If there are groups which we could not unlink from blkcg list, | |
3929 | * wait for a rcu period for them to be freed. | |
3930 | */ | |
3931 | if (cfqd->nr_blkcg_linked_grps) | |
3932 | wait = true; | |
15c31be4 | 3933 | |
d9ff4187 | 3934 | spin_unlock_irq(q->queue_lock); |
a90d742e AV |
3935 | |
3936 | cfq_shutdown_timer_wq(cfqd); | |
3937 | ||
56edf7d7 VG |
3938 | /* |
3939 | * Wait for cfqg->blkg->key accessors to exit their grace periods. | |
3940 | * Do this wait only if there are other unlinked groups out | |
3941 | * there. This can happen if cgroup deletion path claimed the | |
3942 | * responsibility of cleaning up a group before queue cleanup code | |
3943 | * get to the group. | |
3944 | * | |
3945 | * Do not call synchronize_rcu() unconditionally as there are drivers | |
3946 | * which create/delete request queue hundreds of times during scan/boot | |
3947 | * and synchronize_rcu() can take significant time and slow down boot. | |
3948 | */ | |
3949 | if (wait) | |
3950 | synchronize_rcu(); | |
2abae55f VG |
3951 | |
3952 | #ifdef CONFIG_CFQ_GROUP_IOSCHED | |
3953 | /* Free up per cpu stats for root group */ | |
3954 | free_percpu(cfqd->root_group.blkg.stats_cpu); | |
3955 | #endif | |
56edf7d7 | 3956 | kfree(cfqd); |
1da177e4 LT |
3957 | } |
3958 | ||
165125e1 | 3959 | static void *cfq_init_queue(struct request_queue *q) |
1da177e4 LT |
3960 | { |
3961 | struct cfq_data *cfqd; | |
718eee05 | 3962 | int i, j; |
cdb16e8f | 3963 | struct cfq_group *cfqg; |
615f0259 | 3964 | struct cfq_rb_root *st; |
1da177e4 | 3965 | |
94f6030c | 3966 | cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL | __GFP_ZERO, q->node); |
a73f730d | 3967 | if (!cfqd) |
bc1c1169 | 3968 | return NULL; |
80b15c73 | 3969 | |
1fa8f6d6 VG |
3970 | /* Init root service tree */ |
3971 | cfqd->grp_service_tree = CFQ_RB_ROOT; | |
3972 | ||
cdb16e8f VG |
3973 | /* Init root group */ |
3974 | cfqg = &cfqd->root_group; | |
615f0259 VG |
3975 | for_each_cfqg_st(cfqg, i, j, st) |
3976 | *st = CFQ_RB_ROOT; | |
1fa8f6d6 | 3977 | RB_CLEAR_NODE(&cfqg->rb_node); |
26a2ac00 | 3978 | |
25bc6b07 VG |
3979 | /* Give preference to root group over other groups */ |
3980 | cfqg->weight = 2*BLKIO_WEIGHT_DEFAULT; | |
3981 | ||
25fb5169 | 3982 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
b1c35769 | 3983 | /* |
56edf7d7 VG |
3984 | * Set root group reference to 2. One reference will be dropped when |
3985 | * all groups on cfqd->cfqg_list are being deleted during queue exit. | |
3986 | * Other reference will remain there as we don't want to delete this | |
3987 | * group as it is statically allocated and gets destroyed when | |
3988 | * throtl_data goes away. | |
b1c35769 | 3989 | */ |
56edf7d7 | 3990 | cfqg->ref = 2; |
5624a4e4 VG |
3991 | |
3992 | if (blkio_alloc_blkg_stats(&cfqg->blkg)) { | |
3993 | kfree(cfqg); | |
3994 | kfree(cfqd); | |
3995 | return NULL; | |
3996 | } | |
3997 | ||
dcf097b2 | 3998 | rcu_read_lock(); |
5624a4e4 | 3999 | |
e98ef89b VG |
4000 | cfq_blkiocg_add_blkio_group(&blkio_root_cgroup, &cfqg->blkg, |
4001 | (void *)cfqd, 0); | |
dcf097b2 | 4002 | rcu_read_unlock(); |
56edf7d7 VG |
4003 | cfqd->nr_blkcg_linked_grps++; |
4004 | ||
4005 | /* Add group on cfqd->cfqg_list */ | |
4006 | hlist_add_head(&cfqg->cfqd_node, &cfqd->cfqg_list); | |
25fb5169 | 4007 | #endif |
26a2ac00 JA |
4008 | /* |
4009 | * Not strictly needed (since RB_ROOT just clears the node and we | |
4010 | * zeroed cfqd on alloc), but better be safe in case someone decides | |
4011 | * to add magic to the rb code | |
4012 | */ | |
4013 | for (i = 0; i < CFQ_PRIO_LISTS; i++) | |
4014 | cfqd->prio_trees[i] = RB_ROOT; | |
4015 | ||
6118b70b JA |
4016 | /* |
4017 | * Our fallback cfqq if cfq_find_alloc_queue() runs into OOM issues. | |
4018 | * Grab a permanent reference to it, so that the normal code flow | |
4019 | * will not attempt to free it. | |
4020 | */ | |
4021 | cfq_init_cfqq(cfqd, &cfqd->oom_cfqq, 1, 0); | |
30d7b944 | 4022 | cfqd->oom_cfqq.ref++; |
cdb16e8f | 4023 | cfq_link_cfqq_cfqg(&cfqd->oom_cfqq, &cfqd->root_group); |
6118b70b | 4024 | |
d9ff4187 | 4025 | INIT_LIST_HEAD(&cfqd->cic_list); |
1da177e4 | 4026 | |
1da177e4 | 4027 | cfqd->queue = q; |
1da177e4 | 4028 | |
22e2c507 JA |
4029 | init_timer(&cfqd->idle_slice_timer); |
4030 | cfqd->idle_slice_timer.function = cfq_idle_slice_timer; | |
4031 | cfqd->idle_slice_timer.data = (unsigned long) cfqd; | |
4032 | ||
23e018a1 | 4033 | INIT_WORK(&cfqd->unplug_work, cfq_kick_queue); |
22e2c507 | 4034 | |
1da177e4 | 4035 | cfqd->cfq_quantum = cfq_quantum; |
22e2c507 JA |
4036 | cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; |
4037 | cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; | |
1da177e4 LT |
4038 | cfqd->cfq_back_max = cfq_back_max; |
4039 | cfqd->cfq_back_penalty = cfq_back_penalty; | |
22e2c507 JA |
4040 | cfqd->cfq_slice[0] = cfq_slice_async; |
4041 | cfqd->cfq_slice[1] = cfq_slice_sync; | |
4042 | cfqd->cfq_slice_async_rq = cfq_slice_async_rq; | |
4043 | cfqd->cfq_slice_idle = cfq_slice_idle; | |
80bdf0c7 | 4044 | cfqd->cfq_group_idle = cfq_group_idle; |
963b72fc | 4045 | cfqd->cfq_latency = 1; |
e459dd08 | 4046 | cfqd->hw_tag = -1; |
edc71131 CZ |
4047 | /* |
4048 | * we optimistically start assuming sync ops weren't delayed in last | |
4049 | * second, in order to have larger depth for async operations. | |
4050 | */ | |
573412b2 | 4051 | cfqd->last_delayed_sync = jiffies - HZ; |
bc1c1169 | 4052 | return cfqd; |
1da177e4 LT |
4053 | } |
4054 | ||
4055 | static void cfq_slab_kill(void) | |
4056 | { | |
d6de8be7 JA |
4057 | /* |
4058 | * Caller already ensured that pending RCU callbacks are completed, | |
4059 | * so we should have no busy allocations at this point. | |
4060 | */ | |
1da177e4 LT |
4061 | if (cfq_pool) |
4062 | kmem_cache_destroy(cfq_pool); | |
4063 | if (cfq_ioc_pool) | |
4064 | kmem_cache_destroy(cfq_ioc_pool); | |
4065 | } | |
4066 | ||
4067 | static int __init cfq_slab_setup(void) | |
4068 | { | |
0a31bd5f | 4069 | cfq_pool = KMEM_CACHE(cfq_queue, 0); |
1da177e4 LT |
4070 | if (!cfq_pool) |
4071 | goto fail; | |
4072 | ||
34e6bbf2 | 4073 | cfq_ioc_pool = KMEM_CACHE(cfq_io_context, 0); |
1da177e4 LT |
4074 | if (!cfq_ioc_pool) |
4075 | goto fail; | |
4076 | ||
4077 | return 0; | |
4078 | fail: | |
4079 | cfq_slab_kill(); | |
4080 | return -ENOMEM; | |
4081 | } | |
4082 | ||
1da177e4 LT |
4083 | /* |
4084 | * sysfs parts below --> | |
4085 | */ | |
1da177e4 LT |
4086 | static ssize_t |
4087 | cfq_var_show(unsigned int var, char *page) | |
4088 | { | |
4089 | return sprintf(page, "%d\n", var); | |
4090 | } | |
4091 | ||
4092 | static ssize_t | |
4093 | cfq_var_store(unsigned int *var, const char *page, size_t count) | |
4094 | { | |
4095 | char *p = (char *) page; | |
4096 | ||
4097 | *var = simple_strtoul(p, &p, 10); | |
4098 | return count; | |
4099 | } | |
4100 | ||
1da177e4 | 4101 | #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ |
b374d18a | 4102 | static ssize_t __FUNC(struct elevator_queue *e, char *page) \ |
1da177e4 | 4103 | { \ |
3d1ab40f | 4104 | struct cfq_data *cfqd = e->elevator_data; \ |
1da177e4 LT |
4105 | unsigned int __data = __VAR; \ |
4106 | if (__CONV) \ | |
4107 | __data = jiffies_to_msecs(__data); \ | |
4108 | return cfq_var_show(__data, (page)); \ | |
4109 | } | |
4110 | SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); | |
22e2c507 JA |
4111 | SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1); |
4112 | SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1); | |
e572ec7e AV |
4113 | SHOW_FUNCTION(cfq_back_seek_max_show, cfqd->cfq_back_max, 0); |
4114 | SHOW_FUNCTION(cfq_back_seek_penalty_show, cfqd->cfq_back_penalty, 0); | |
22e2c507 | 4115 | SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1); |
80bdf0c7 | 4116 | SHOW_FUNCTION(cfq_group_idle_show, cfqd->cfq_group_idle, 1); |
22e2c507 JA |
4117 | SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1); |
4118 | SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1); | |
4119 | SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0); | |
963b72fc | 4120 | SHOW_FUNCTION(cfq_low_latency_show, cfqd->cfq_latency, 0); |
1da177e4 LT |
4121 | #undef SHOW_FUNCTION |
4122 | ||
4123 | #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ | |
b374d18a | 4124 | static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \ |
1da177e4 | 4125 | { \ |
3d1ab40f | 4126 | struct cfq_data *cfqd = e->elevator_data; \ |
1da177e4 LT |
4127 | unsigned int __data; \ |
4128 | int ret = cfq_var_store(&__data, (page), count); \ | |
4129 | if (__data < (MIN)) \ | |
4130 | __data = (MIN); \ | |
4131 | else if (__data > (MAX)) \ | |
4132 | __data = (MAX); \ | |
4133 | if (__CONV) \ | |
4134 | *(__PTR) = msecs_to_jiffies(__data); \ | |
4135 | else \ | |
4136 | *(__PTR) = __data; \ | |
4137 | return ret; \ | |
4138 | } | |
4139 | STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); | |
fe094d98 JA |
4140 | STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, |
4141 | UINT_MAX, 1); | |
4142 | STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, | |
4143 | UINT_MAX, 1); | |
e572ec7e | 4144 | STORE_FUNCTION(cfq_back_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); |
fe094d98 JA |
4145 | STORE_FUNCTION(cfq_back_seek_penalty_store, &cfqd->cfq_back_penalty, 1, |
4146 | UINT_MAX, 0); | |
22e2c507 | 4147 | STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1); |
80bdf0c7 | 4148 | STORE_FUNCTION(cfq_group_idle_store, &cfqd->cfq_group_idle, 0, UINT_MAX, 1); |
22e2c507 JA |
4149 | STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1); |
4150 | STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1); | |
fe094d98 JA |
4151 | STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, |
4152 | UINT_MAX, 0); | |
963b72fc | 4153 | STORE_FUNCTION(cfq_low_latency_store, &cfqd->cfq_latency, 0, 1, 0); |
1da177e4 LT |
4154 | #undef STORE_FUNCTION |
4155 | ||
e572ec7e AV |
4156 | #define CFQ_ATTR(name) \ |
4157 | __ATTR(name, S_IRUGO|S_IWUSR, cfq_##name##_show, cfq_##name##_store) | |
4158 | ||
4159 | static struct elv_fs_entry cfq_attrs[] = { | |
4160 | CFQ_ATTR(quantum), | |
e572ec7e AV |
4161 | CFQ_ATTR(fifo_expire_sync), |
4162 | CFQ_ATTR(fifo_expire_async), | |
4163 | CFQ_ATTR(back_seek_max), | |
4164 | CFQ_ATTR(back_seek_penalty), | |
4165 | CFQ_ATTR(slice_sync), | |
4166 | CFQ_ATTR(slice_async), | |
4167 | CFQ_ATTR(slice_async_rq), | |
4168 | CFQ_ATTR(slice_idle), | |
80bdf0c7 | 4169 | CFQ_ATTR(group_idle), |
963b72fc | 4170 | CFQ_ATTR(low_latency), |
e572ec7e | 4171 | __ATTR_NULL |
1da177e4 LT |
4172 | }; |
4173 | ||
1da177e4 LT |
4174 | static struct elevator_type iosched_cfq = { |
4175 | .ops = { | |
4176 | .elevator_merge_fn = cfq_merge, | |
4177 | .elevator_merged_fn = cfq_merged_request, | |
4178 | .elevator_merge_req_fn = cfq_merged_requests, | |
da775265 | 4179 | .elevator_allow_merge_fn = cfq_allow_merge, |
812d4026 | 4180 | .elevator_bio_merged_fn = cfq_bio_merged, |
b4878f24 | 4181 | .elevator_dispatch_fn = cfq_dispatch_requests, |
1da177e4 | 4182 | .elevator_add_req_fn = cfq_insert_request, |
b4878f24 | 4183 | .elevator_activate_req_fn = cfq_activate_request, |
1da177e4 | 4184 | .elevator_deactivate_req_fn = cfq_deactivate_request, |
1da177e4 | 4185 | .elevator_completed_req_fn = cfq_completed_request, |
21183b07 JA |
4186 | .elevator_former_req_fn = elv_rb_former_request, |
4187 | .elevator_latter_req_fn = elv_rb_latter_request, | |
1da177e4 LT |
4188 | .elevator_set_req_fn = cfq_set_request, |
4189 | .elevator_put_req_fn = cfq_put_request, | |
4190 | .elevator_may_queue_fn = cfq_may_queue, | |
4191 | .elevator_init_fn = cfq_init_queue, | |
4192 | .elevator_exit_fn = cfq_exit_queue, | |
fc46379d | 4193 | .trim = cfq_free_io_context, |
1da177e4 | 4194 | }, |
3d1ab40f | 4195 | .elevator_attrs = cfq_attrs, |
1da177e4 LT |
4196 | .elevator_name = "cfq", |
4197 | .elevator_owner = THIS_MODULE, | |
4198 | }; | |
4199 | ||
3e252066 VG |
4200 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
4201 | static struct blkio_policy_type blkio_policy_cfq = { | |
4202 | .ops = { | |
4203 | .blkio_unlink_group_fn = cfq_unlink_blkio_group, | |
4204 | .blkio_update_group_weight_fn = cfq_update_blkio_group_weight, | |
4205 | }, | |
062a644d | 4206 | .plid = BLKIO_POLICY_PROP, |
3e252066 VG |
4207 | }; |
4208 | #else | |
4209 | static struct blkio_policy_type blkio_policy_cfq; | |
4210 | #endif | |
4211 | ||
1da177e4 LT |
4212 | static int __init cfq_init(void) |
4213 | { | |
22e2c507 JA |
4214 | /* |
4215 | * could be 0 on HZ < 1000 setups | |
4216 | */ | |
4217 | if (!cfq_slice_async) | |
4218 | cfq_slice_async = 1; | |
4219 | if (!cfq_slice_idle) | |
4220 | cfq_slice_idle = 1; | |
4221 | ||
80bdf0c7 VG |
4222 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
4223 | if (!cfq_group_idle) | |
4224 | cfq_group_idle = 1; | |
4225 | #else | |
4226 | cfq_group_idle = 0; | |
4227 | #endif | |
1da177e4 LT |
4228 | if (cfq_slab_setup()) |
4229 | return -ENOMEM; | |
4230 | ||
2fdd82bd | 4231 | elv_register(&iosched_cfq); |
3e252066 | 4232 | blkio_policy_register(&blkio_policy_cfq); |
1da177e4 | 4233 | |
2fdd82bd | 4234 | return 0; |
1da177e4 LT |
4235 | } |
4236 | ||
4237 | static void __exit cfq_exit(void) | |
4238 | { | |
6e9a4738 | 4239 | DECLARE_COMPLETION_ONSTACK(all_gone); |
3e252066 | 4240 | blkio_policy_unregister(&blkio_policy_cfq); |
1da177e4 | 4241 | elv_unregister(&iosched_cfq); |
334e94de | 4242 | ioc_gone = &all_gone; |
fba82272 OH |
4243 | /* ioc_gone's update must be visible before reading ioc_count */ |
4244 | smp_wmb(); | |
d6de8be7 JA |
4245 | |
4246 | /* | |
4247 | * this also protects us from entering cfq_slab_kill() with | |
4248 | * pending RCU callbacks | |
4249 | */ | |
245b2e70 | 4250 | if (elv_ioc_count_read(cfq_ioc_count)) |
9a11b4ed | 4251 | wait_for_completion(&all_gone); |
83521d3e | 4252 | cfq_slab_kill(); |
1da177e4 LT |
4253 | } |
4254 | ||
4255 | module_init(cfq_init); | |
4256 | module_exit(cfq_exit); | |
4257 | ||
4258 | MODULE_AUTHOR("Jens Axboe"); | |
4259 | MODULE_LICENSE("GPL"); | |
4260 | MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler"); |