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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> |
e98ef89b | 17 | #include "cfq.h" |
1da177e4 LT |
18 | |
19 | /* | |
20 | * tunables | |
21 | */ | |
fe094d98 | 22 | /* max queue in one round of service */ |
abc3c744 | 23 | static const int cfq_quantum = 8; |
64100099 | 24 | static const int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 }; |
fe094d98 JA |
25 | /* maximum backwards seek, in KiB */ |
26 | static const int cfq_back_max = 16 * 1024; | |
27 | /* penalty of a backwards seek */ | |
28 | static const int cfq_back_penalty = 2; | |
64100099 | 29 | static const int cfq_slice_sync = HZ / 10; |
3b18152c | 30 | static int cfq_slice_async = HZ / 25; |
64100099 | 31 | static const int cfq_slice_async_rq = 2; |
caaa5f9f | 32 | static int cfq_slice_idle = HZ / 125; |
80bdf0c7 | 33 | static int cfq_group_idle = HZ / 125; |
5db5d642 CZ |
34 | static const int cfq_target_latency = HZ * 3/10; /* 300 ms */ |
35 | static const int cfq_hist_divisor = 4; | |
22e2c507 | 36 | |
d9e7620e | 37 | /* |
0871714e | 38 | * offset from end of service tree |
d9e7620e | 39 | */ |
0871714e | 40 | #define CFQ_IDLE_DELAY (HZ / 5) |
d9e7620e JA |
41 | |
42 | /* | |
43 | * below this threshold, we consider thinktime immediate | |
44 | */ | |
45 | #define CFQ_MIN_TT (2) | |
46 | ||
22e2c507 | 47 | #define CFQ_SLICE_SCALE (5) |
45333d5a | 48 | #define CFQ_HW_QUEUE_MIN (5) |
25bc6b07 | 49 | #define CFQ_SERVICE_SHIFT 12 |
22e2c507 | 50 | |
3dde36dd | 51 | #define CFQQ_SEEK_THR (sector_t)(8 * 100) |
e9ce335d | 52 | #define CFQQ_CLOSE_THR (sector_t)(8 * 1024) |
41647e7a | 53 | #define CFQQ_SECT_THR_NONROT (sector_t)(2 * 32) |
3dde36dd | 54 | #define CFQQ_SEEKY(cfqq) (hweight32(cfqq->seek_history) > 32/8) |
ae54abed | 55 | |
fe094d98 | 56 | #define RQ_CIC(rq) \ |
c186794d MS |
57 | ((struct cfq_io_context *) (rq)->elevator_private[0]) |
58 | #define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elevator_private[1]) | |
59 | #define RQ_CFQG(rq) (struct cfq_group *) ((rq)->elevator_private[2]) | |
1da177e4 | 60 | |
e18b890b CL |
61 | static struct kmem_cache *cfq_pool; |
62 | static struct kmem_cache *cfq_ioc_pool; | |
1da177e4 | 63 | |
245b2e70 | 64 | static DEFINE_PER_CPU(unsigned long, cfq_ioc_count); |
334e94de | 65 | static struct completion *ioc_gone; |
9a11b4ed | 66 | static DEFINE_SPINLOCK(ioc_gone_lock); |
334e94de | 67 | |
80b15c73 KK |
68 | static DEFINE_SPINLOCK(cic_index_lock); |
69 | static DEFINE_IDA(cic_index_ida); | |
70 | ||
22e2c507 JA |
71 | #define CFQ_PRIO_LISTS IOPRIO_BE_NR |
72 | #define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE) | |
22e2c507 JA |
73 | #define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT) |
74 | ||
206dc69b | 75 | #define sample_valid(samples) ((samples) > 80) |
1fa8f6d6 | 76 | #define rb_entry_cfqg(node) rb_entry((node), struct cfq_group, rb_node) |
206dc69b | 77 | |
cc09e299 JA |
78 | /* |
79 | * Most of our rbtree usage is for sorting with min extraction, so | |
80 | * if we cache the leftmost node we don't have to walk down the tree | |
81 | * to find it. Idea borrowed from Ingo Molnars CFS scheduler. We should | |
82 | * move this into the elevator for the rq sorting as well. | |
83 | */ | |
84 | struct cfq_rb_root { | |
85 | struct rb_root rb; | |
86 | struct rb_node *left; | |
aa6f6a3d | 87 | unsigned count; |
73e9ffdd | 88 | unsigned total_weight; |
1fa8f6d6 | 89 | u64 min_vdisktime; |
cc09e299 | 90 | }; |
73e9ffdd RK |
91 | #define CFQ_RB_ROOT (struct cfq_rb_root) { .rb = RB_ROOT, .left = NULL, \ |
92 | .count = 0, .min_vdisktime = 0, } | |
cc09e299 | 93 | |
6118b70b JA |
94 | /* |
95 | * Per process-grouping structure | |
96 | */ | |
97 | struct cfq_queue { | |
98 | /* reference count */ | |
30d7b944 | 99 | int ref; |
6118b70b JA |
100 | /* various state flags, see below */ |
101 | unsigned int flags; | |
102 | /* parent cfq_data */ | |
103 | struct cfq_data *cfqd; | |
104 | /* service_tree member */ | |
105 | struct rb_node rb_node; | |
106 | /* service_tree key */ | |
107 | unsigned long rb_key; | |
108 | /* prio tree member */ | |
109 | struct rb_node p_node; | |
110 | /* prio tree root we belong to, if any */ | |
111 | struct rb_root *p_root; | |
112 | /* sorted list of pending requests */ | |
113 | struct rb_root sort_list; | |
114 | /* if fifo isn't expired, next request to serve */ | |
115 | struct request *next_rq; | |
116 | /* requests queued in sort_list */ | |
117 | int queued[2]; | |
118 | /* currently allocated requests */ | |
119 | int allocated[2]; | |
120 | /* fifo list of requests in sort_list */ | |
121 | struct list_head fifo; | |
122 | ||
dae739eb VG |
123 | /* time when queue got scheduled in to dispatch first request. */ |
124 | unsigned long dispatch_start; | |
f75edf2d | 125 | unsigned int allocated_slice; |
c4081ba5 | 126 | unsigned int slice_dispatch; |
dae739eb VG |
127 | /* time when first request from queue completed and slice started. */ |
128 | unsigned long slice_start; | |
6118b70b JA |
129 | unsigned long slice_end; |
130 | long slice_resid; | |
6118b70b JA |
131 | |
132 | /* pending metadata requests */ | |
133 | int meta_pending; | |
134 | /* number of requests that are on the dispatch list or inside driver */ | |
135 | int dispatched; | |
136 | ||
137 | /* io prio of this group */ | |
138 | unsigned short ioprio, org_ioprio; | |
139 | unsigned short ioprio_class, org_ioprio_class; | |
140 | ||
c4081ba5 RK |
141 | pid_t pid; |
142 | ||
3dde36dd | 143 | u32 seek_history; |
b2c18e1e JM |
144 | sector_t last_request_pos; |
145 | ||
aa6f6a3d | 146 | struct cfq_rb_root *service_tree; |
df5fe3e8 | 147 | struct cfq_queue *new_cfqq; |
cdb16e8f | 148 | struct cfq_group *cfqg; |
c4e7893e VG |
149 | /* Number of sectors dispatched from queue in single dispatch round */ |
150 | unsigned long nr_sectors; | |
6118b70b JA |
151 | }; |
152 | ||
c0324a02 | 153 | /* |
718eee05 | 154 | * First index in the service_trees. |
c0324a02 CZ |
155 | * IDLE is handled separately, so it has negative index |
156 | */ | |
157 | enum wl_prio_t { | |
c0324a02 | 158 | BE_WORKLOAD = 0, |
615f0259 VG |
159 | RT_WORKLOAD = 1, |
160 | IDLE_WORKLOAD = 2, | |
b4627321 | 161 | CFQ_PRIO_NR, |
c0324a02 CZ |
162 | }; |
163 | ||
718eee05 CZ |
164 | /* |
165 | * Second index in the service_trees. | |
166 | */ | |
167 | enum wl_type_t { | |
168 | ASYNC_WORKLOAD = 0, | |
169 | SYNC_NOIDLE_WORKLOAD = 1, | |
170 | SYNC_WORKLOAD = 2 | |
171 | }; | |
172 | ||
cdb16e8f VG |
173 | /* This is per cgroup per device grouping structure */ |
174 | struct cfq_group { | |
1fa8f6d6 VG |
175 | /* group service_tree member */ |
176 | struct rb_node rb_node; | |
177 | ||
178 | /* group service_tree key */ | |
179 | u64 vdisktime; | |
25bc6b07 | 180 | unsigned int weight; |
8184f93e JT |
181 | unsigned int new_weight; |
182 | bool needs_update; | |
1fa8f6d6 VG |
183 | |
184 | /* number of cfqq currently on this group */ | |
185 | int nr_cfqq; | |
186 | ||
cdb16e8f | 187 | /* |
b4627321 VG |
188 | * Per group busy queus average. Useful for workload slice calc. We |
189 | * create the array for each prio class but at run time it is used | |
190 | * only for RT and BE class and slot for IDLE class remains unused. | |
191 | * This is primarily done to avoid confusion and a gcc warning. | |
192 | */ | |
193 | unsigned int busy_queues_avg[CFQ_PRIO_NR]; | |
194 | /* | |
195 | * rr lists of queues with requests. We maintain service trees for | |
196 | * RT and BE classes. These trees are subdivided in subclasses | |
197 | * of SYNC, SYNC_NOIDLE and ASYNC based on workload type. For IDLE | |
198 | * class there is no subclassification and all the cfq queues go on | |
199 | * a single tree service_tree_idle. | |
cdb16e8f VG |
200 | * Counts are embedded in the cfq_rb_root |
201 | */ | |
202 | struct cfq_rb_root service_trees[2][3]; | |
203 | struct cfq_rb_root service_tree_idle; | |
dae739eb VG |
204 | |
205 | unsigned long saved_workload_slice; | |
206 | enum wl_type_t saved_workload; | |
207 | enum wl_prio_t saved_serving_prio; | |
25fb5169 VG |
208 | struct blkio_group blkg; |
209 | #ifdef CONFIG_CFQ_GROUP_IOSCHED | |
210 | struct hlist_node cfqd_node; | |
329a6781 | 211 | int ref; |
25fb5169 | 212 | #endif |
80bdf0c7 VG |
213 | /* number of requests that are on the dispatch list or inside driver */ |
214 | int dispatched; | |
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 | 290 | |
80b15c73 | 291 | unsigned int cic_index; |
d9ff4187 | 292 | struct list_head cic_list; |
1da177e4 | 293 | |
6118b70b JA |
294 | /* |
295 | * Fallback dummy cfqq for extreme OOM conditions | |
296 | */ | |
297 | struct cfq_queue oom_cfqq; | |
365722bb | 298 | |
573412b2 | 299 | unsigned long last_delayed_sync; |
25fb5169 VG |
300 | |
301 | /* List of cfq groups being managed on this device*/ | |
302 | struct hlist_head cfqg_list; | |
bb729bc9 | 303 | struct rcu_head rcu; |
1da177e4 LT |
304 | }; |
305 | ||
25fb5169 VG |
306 | static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd); |
307 | ||
cdb16e8f VG |
308 | static struct cfq_rb_root *service_tree_for(struct cfq_group *cfqg, |
309 | enum wl_prio_t prio, | |
65b32a57 | 310 | enum wl_type_t type) |
c0324a02 | 311 | { |
1fa8f6d6 VG |
312 | if (!cfqg) |
313 | return NULL; | |
314 | ||
c0324a02 | 315 | if (prio == IDLE_WORKLOAD) |
cdb16e8f | 316 | return &cfqg->service_tree_idle; |
c0324a02 | 317 | |
cdb16e8f | 318 | return &cfqg->service_trees[prio][type]; |
c0324a02 CZ |
319 | } |
320 | ||
3b18152c | 321 | enum cfqq_state_flags { |
b0b8d749 JA |
322 | CFQ_CFQQ_FLAG_on_rr = 0, /* on round-robin busy list */ |
323 | CFQ_CFQQ_FLAG_wait_request, /* waiting for a request */ | |
b029195d | 324 | CFQ_CFQQ_FLAG_must_dispatch, /* must be allowed a dispatch */ |
b0b8d749 | 325 | CFQ_CFQQ_FLAG_must_alloc_slice, /* per-slice must_alloc flag */ |
b0b8d749 JA |
326 | CFQ_CFQQ_FLAG_fifo_expire, /* FIFO checked in this slice */ |
327 | CFQ_CFQQ_FLAG_idle_window, /* slice idling enabled */ | |
328 | CFQ_CFQQ_FLAG_prio_changed, /* task priority has changed */ | |
44f7c160 | 329 | CFQ_CFQQ_FLAG_slice_new, /* no requests dispatched in slice */ |
91fac317 | 330 | CFQ_CFQQ_FLAG_sync, /* synchronous queue */ |
b3b6d040 | 331 | CFQ_CFQQ_FLAG_coop, /* cfqq is shared */ |
ae54abed | 332 | CFQ_CFQQ_FLAG_split_coop, /* shared cfqq will be splitted */ |
76280aff | 333 | CFQ_CFQQ_FLAG_deep, /* sync cfqq experienced large depth */ |
f75edf2d | 334 | CFQ_CFQQ_FLAG_wait_busy, /* Waiting for next request */ |
3b18152c JA |
335 | }; |
336 | ||
337 | #define CFQ_CFQQ_FNS(name) \ | |
338 | static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \ | |
339 | { \ | |
fe094d98 | 340 | (cfqq)->flags |= (1 << CFQ_CFQQ_FLAG_##name); \ |
3b18152c JA |
341 | } \ |
342 | static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \ | |
343 | { \ | |
fe094d98 | 344 | (cfqq)->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \ |
3b18152c JA |
345 | } \ |
346 | static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \ | |
347 | { \ | |
fe094d98 | 348 | return ((cfqq)->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \ |
3b18152c JA |
349 | } |
350 | ||
351 | CFQ_CFQQ_FNS(on_rr); | |
352 | CFQ_CFQQ_FNS(wait_request); | |
b029195d | 353 | CFQ_CFQQ_FNS(must_dispatch); |
3b18152c | 354 | CFQ_CFQQ_FNS(must_alloc_slice); |
3b18152c JA |
355 | CFQ_CFQQ_FNS(fifo_expire); |
356 | CFQ_CFQQ_FNS(idle_window); | |
357 | CFQ_CFQQ_FNS(prio_changed); | |
44f7c160 | 358 | CFQ_CFQQ_FNS(slice_new); |
91fac317 | 359 | CFQ_CFQQ_FNS(sync); |
a36e71f9 | 360 | CFQ_CFQQ_FNS(coop); |
ae54abed | 361 | CFQ_CFQQ_FNS(split_coop); |
76280aff | 362 | CFQ_CFQQ_FNS(deep); |
f75edf2d | 363 | CFQ_CFQQ_FNS(wait_busy); |
3b18152c JA |
364 | #undef CFQ_CFQQ_FNS |
365 | ||
afc24d49 | 366 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
2868ef7b VG |
367 | #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \ |
368 | blk_add_trace_msg((cfqd)->queue, "cfq%d%c %s " fmt, (cfqq)->pid, \ | |
369 | cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \ | |
370 | blkg_path(&(cfqq)->cfqg->blkg), ##args); | |
371 | ||
372 | #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) \ | |
373 | blk_add_trace_msg((cfqd)->queue, "%s " fmt, \ | |
374 | blkg_path(&(cfqg)->blkg), ##args); \ | |
375 | ||
376 | #else | |
7b679138 JA |
377 | #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \ |
378 | blk_add_trace_msg((cfqd)->queue, "cfq%d " fmt, (cfqq)->pid, ##args) | |
2868ef7b VG |
379 | #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) do {} while (0); |
380 | #endif | |
7b679138 JA |
381 | #define cfq_log(cfqd, fmt, args...) \ |
382 | blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args) | |
383 | ||
615f0259 VG |
384 | /* Traverses through cfq group service trees */ |
385 | #define for_each_cfqg_st(cfqg, i, j, st) \ | |
386 | for (i = 0; i <= IDLE_WORKLOAD; i++) \ | |
387 | for (j = 0, st = i < IDLE_WORKLOAD ? &cfqg->service_trees[i][j]\ | |
388 | : &cfqg->service_tree_idle; \ | |
389 | (i < IDLE_WORKLOAD && j <= SYNC_WORKLOAD) || \ | |
390 | (i == IDLE_WORKLOAD && j == 0); \ | |
391 | j++, st = i < IDLE_WORKLOAD ? \ | |
392 | &cfqg->service_trees[i][j]: NULL) \ | |
393 | ||
394 | ||
02b35081 VG |
395 | static inline bool iops_mode(struct cfq_data *cfqd) |
396 | { | |
397 | /* | |
398 | * If we are not idling on queues and it is a NCQ drive, parallel | |
399 | * execution of requests is on and measuring time is not possible | |
400 | * in most of the cases until and unless we drive shallower queue | |
401 | * depths and that becomes a performance bottleneck. In such cases | |
402 | * switch to start providing fairness in terms of number of IOs. | |
403 | */ | |
404 | if (!cfqd->cfq_slice_idle && cfqd->hw_tag) | |
405 | return true; | |
406 | else | |
407 | return false; | |
408 | } | |
409 | ||
c0324a02 CZ |
410 | static inline enum wl_prio_t cfqq_prio(struct cfq_queue *cfqq) |
411 | { | |
412 | if (cfq_class_idle(cfqq)) | |
413 | return IDLE_WORKLOAD; | |
414 | if (cfq_class_rt(cfqq)) | |
415 | return RT_WORKLOAD; | |
416 | return BE_WORKLOAD; | |
417 | } | |
418 | ||
718eee05 CZ |
419 | |
420 | static enum wl_type_t cfqq_type(struct cfq_queue *cfqq) | |
421 | { | |
422 | if (!cfq_cfqq_sync(cfqq)) | |
423 | return ASYNC_WORKLOAD; | |
424 | if (!cfq_cfqq_idle_window(cfqq)) | |
425 | return SYNC_NOIDLE_WORKLOAD; | |
426 | return SYNC_WORKLOAD; | |
427 | } | |
428 | ||
58ff82f3 VG |
429 | static inline int cfq_group_busy_queues_wl(enum wl_prio_t wl, |
430 | struct cfq_data *cfqd, | |
431 | struct cfq_group *cfqg) | |
c0324a02 CZ |
432 | { |
433 | if (wl == IDLE_WORKLOAD) | |
cdb16e8f | 434 | return cfqg->service_tree_idle.count; |
c0324a02 | 435 | |
cdb16e8f VG |
436 | return cfqg->service_trees[wl][ASYNC_WORKLOAD].count |
437 | + cfqg->service_trees[wl][SYNC_NOIDLE_WORKLOAD].count | |
438 | + cfqg->service_trees[wl][SYNC_WORKLOAD].count; | |
c0324a02 CZ |
439 | } |
440 | ||
f26bd1f0 VG |
441 | static inline int cfqg_busy_async_queues(struct cfq_data *cfqd, |
442 | struct cfq_group *cfqg) | |
443 | { | |
444 | return cfqg->service_trees[RT_WORKLOAD][ASYNC_WORKLOAD].count | |
445 | + cfqg->service_trees[BE_WORKLOAD][ASYNC_WORKLOAD].count; | |
446 | } | |
447 | ||
165125e1 | 448 | static void cfq_dispatch_insert(struct request_queue *, struct request *); |
a6151c3a | 449 | static struct cfq_queue *cfq_get_queue(struct cfq_data *, bool, |
fd0928df | 450 | struct io_context *, gfp_t); |
4ac845a2 | 451 | static struct cfq_io_context *cfq_cic_lookup(struct cfq_data *, |
91fac317 VT |
452 | struct io_context *); |
453 | ||
454 | static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_context *cic, | |
a6151c3a | 455 | bool is_sync) |
91fac317 | 456 | { |
a6151c3a | 457 | return cic->cfqq[is_sync]; |
91fac317 VT |
458 | } |
459 | ||
460 | static inline void cic_set_cfqq(struct cfq_io_context *cic, | |
a6151c3a | 461 | struct cfq_queue *cfqq, bool is_sync) |
91fac317 | 462 | { |
a6151c3a | 463 | cic->cfqq[is_sync] = cfqq; |
91fac317 VT |
464 | } |
465 | ||
bca4b914 | 466 | #define CIC_DEAD_KEY 1ul |
80b15c73 | 467 | #define CIC_DEAD_INDEX_SHIFT 1 |
bca4b914 KK |
468 | |
469 | static inline void *cfqd_dead_key(struct cfq_data *cfqd) | |
470 | { | |
80b15c73 | 471 | return (void *)(cfqd->cic_index << CIC_DEAD_INDEX_SHIFT | CIC_DEAD_KEY); |
bca4b914 KK |
472 | } |
473 | ||
474 | static inline struct cfq_data *cic_to_cfqd(struct cfq_io_context *cic) | |
475 | { | |
476 | struct cfq_data *cfqd = cic->key; | |
477 | ||
478 | if (unlikely((unsigned long) cfqd & CIC_DEAD_KEY)) | |
479 | return NULL; | |
480 | ||
481 | return cfqd; | |
482 | } | |
483 | ||
91fac317 VT |
484 | /* |
485 | * We regard a request as SYNC, if it's either a read or has the SYNC bit | |
486 | * set (in which case it could also be direct WRITE). | |
487 | */ | |
a6151c3a | 488 | static inline bool cfq_bio_sync(struct bio *bio) |
91fac317 | 489 | { |
7b6d91da | 490 | return bio_data_dir(bio) == READ || (bio->bi_rw & REQ_SYNC); |
91fac317 | 491 | } |
1da177e4 | 492 | |
99f95e52 AM |
493 | /* |
494 | * scheduler run of queue, if there are requests pending and no one in the | |
495 | * driver that will restart queueing | |
496 | */ | |
23e018a1 | 497 | static inline void cfq_schedule_dispatch(struct cfq_data *cfqd) |
99f95e52 | 498 | { |
7b679138 JA |
499 | if (cfqd->busy_queues) { |
500 | cfq_log(cfqd, "schedule dispatch"); | |
23e018a1 | 501 | kblockd_schedule_work(cfqd->queue, &cfqd->unplug_work); |
7b679138 | 502 | } |
99f95e52 AM |
503 | } |
504 | ||
44f7c160 JA |
505 | /* |
506 | * Scale schedule slice based on io priority. Use the sync time slice only | |
507 | * if a queue is marked sync and has sync io queued. A sync queue with async | |
508 | * io only, should not get full sync slice length. | |
509 | */ | |
a6151c3a | 510 | static inline int cfq_prio_slice(struct cfq_data *cfqd, bool sync, |
d9e7620e | 511 | unsigned short prio) |
44f7c160 | 512 | { |
d9e7620e | 513 | const int base_slice = cfqd->cfq_slice[sync]; |
44f7c160 | 514 | |
d9e7620e JA |
515 | WARN_ON(prio >= IOPRIO_BE_NR); |
516 | ||
517 | return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - prio)); | |
518 | } | |
44f7c160 | 519 | |
d9e7620e JA |
520 | static inline int |
521 | cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
522 | { | |
523 | return cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio); | |
44f7c160 JA |
524 | } |
525 | ||
25bc6b07 VG |
526 | static inline u64 cfq_scale_slice(unsigned long delta, struct cfq_group *cfqg) |
527 | { | |
528 | u64 d = delta << CFQ_SERVICE_SHIFT; | |
529 | ||
530 | d = d * BLKIO_WEIGHT_DEFAULT; | |
531 | do_div(d, cfqg->weight); | |
532 | return d; | |
533 | } | |
534 | ||
535 | static inline u64 max_vdisktime(u64 min_vdisktime, u64 vdisktime) | |
536 | { | |
537 | s64 delta = (s64)(vdisktime - min_vdisktime); | |
538 | if (delta > 0) | |
539 | min_vdisktime = vdisktime; | |
540 | ||
541 | return min_vdisktime; | |
542 | } | |
543 | ||
544 | static inline u64 min_vdisktime(u64 min_vdisktime, u64 vdisktime) | |
545 | { | |
546 | s64 delta = (s64)(vdisktime - min_vdisktime); | |
547 | if (delta < 0) | |
548 | min_vdisktime = vdisktime; | |
549 | ||
550 | return min_vdisktime; | |
551 | } | |
552 | ||
553 | static void update_min_vdisktime(struct cfq_rb_root *st) | |
554 | { | |
25bc6b07 VG |
555 | struct cfq_group *cfqg; |
556 | ||
25bc6b07 VG |
557 | if (st->left) { |
558 | cfqg = rb_entry_cfqg(st->left); | |
a6032710 GJ |
559 | st->min_vdisktime = max_vdisktime(st->min_vdisktime, |
560 | cfqg->vdisktime); | |
25bc6b07 | 561 | } |
25bc6b07 VG |
562 | } |
563 | ||
5db5d642 CZ |
564 | /* |
565 | * get averaged number of queues of RT/BE priority. | |
566 | * average is updated, with a formula that gives more weight to higher numbers, | |
567 | * to quickly follows sudden increases and decrease slowly | |
568 | */ | |
569 | ||
58ff82f3 VG |
570 | static inline unsigned cfq_group_get_avg_queues(struct cfq_data *cfqd, |
571 | struct cfq_group *cfqg, bool rt) | |
5869619c | 572 | { |
5db5d642 CZ |
573 | unsigned min_q, max_q; |
574 | unsigned mult = cfq_hist_divisor - 1; | |
575 | unsigned round = cfq_hist_divisor / 2; | |
58ff82f3 | 576 | unsigned busy = cfq_group_busy_queues_wl(rt, cfqd, cfqg); |
5db5d642 | 577 | |
58ff82f3 VG |
578 | min_q = min(cfqg->busy_queues_avg[rt], busy); |
579 | max_q = max(cfqg->busy_queues_avg[rt], busy); | |
580 | cfqg->busy_queues_avg[rt] = (mult * max_q + min_q + round) / | |
5db5d642 | 581 | cfq_hist_divisor; |
58ff82f3 VG |
582 | return cfqg->busy_queues_avg[rt]; |
583 | } | |
584 | ||
585 | static inline unsigned | |
586 | cfq_group_slice(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
587 | { | |
588 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
589 | ||
590 | return cfq_target_latency * cfqg->weight / st->total_weight; | |
5db5d642 CZ |
591 | } |
592 | ||
c553f8e3 | 593 | static inline unsigned |
ba5bd520 | 594 | cfq_scaled_cfqq_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
44f7c160 | 595 | { |
5db5d642 CZ |
596 | unsigned slice = cfq_prio_to_slice(cfqd, cfqq); |
597 | if (cfqd->cfq_latency) { | |
58ff82f3 VG |
598 | /* |
599 | * interested queues (we consider only the ones with the same | |
600 | * priority class in the cfq group) | |
601 | */ | |
602 | unsigned iq = cfq_group_get_avg_queues(cfqd, cfqq->cfqg, | |
603 | cfq_class_rt(cfqq)); | |
5db5d642 CZ |
604 | unsigned sync_slice = cfqd->cfq_slice[1]; |
605 | unsigned expect_latency = sync_slice * iq; | |
58ff82f3 VG |
606 | unsigned group_slice = cfq_group_slice(cfqd, cfqq->cfqg); |
607 | ||
608 | if (expect_latency > group_slice) { | |
5db5d642 CZ |
609 | unsigned base_low_slice = 2 * cfqd->cfq_slice_idle; |
610 | /* scale low_slice according to IO priority | |
611 | * and sync vs async */ | |
612 | unsigned low_slice = | |
613 | min(slice, base_low_slice * slice / sync_slice); | |
614 | /* the adapted slice value is scaled to fit all iqs | |
615 | * into the target latency */ | |
58ff82f3 | 616 | slice = max(slice * group_slice / expect_latency, |
5db5d642 CZ |
617 | low_slice); |
618 | } | |
619 | } | |
c553f8e3 SL |
620 | return slice; |
621 | } | |
622 | ||
623 | static inline void | |
624 | cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
625 | { | |
ba5bd520 | 626 | unsigned slice = cfq_scaled_cfqq_slice(cfqd, cfqq); |
c553f8e3 | 627 | |
dae739eb | 628 | cfqq->slice_start = jiffies; |
5db5d642 | 629 | cfqq->slice_end = jiffies + slice; |
f75edf2d | 630 | cfqq->allocated_slice = slice; |
7b679138 | 631 | cfq_log_cfqq(cfqd, cfqq, "set_slice=%lu", cfqq->slice_end - jiffies); |
44f7c160 JA |
632 | } |
633 | ||
634 | /* | |
635 | * We need to wrap this check in cfq_cfqq_slice_new(), since ->slice_end | |
636 | * isn't valid until the first request from the dispatch is activated | |
637 | * and the slice time set. | |
638 | */ | |
a6151c3a | 639 | static inline bool cfq_slice_used(struct cfq_queue *cfqq) |
44f7c160 JA |
640 | { |
641 | if (cfq_cfqq_slice_new(cfqq)) | |
c1e44756 | 642 | return false; |
44f7c160 | 643 | if (time_before(jiffies, cfqq->slice_end)) |
c1e44756 | 644 | return false; |
44f7c160 | 645 | |
c1e44756 | 646 | return true; |
44f7c160 JA |
647 | } |
648 | ||
1da177e4 | 649 | /* |
5e705374 | 650 | * Lifted from AS - choose which of rq1 and rq2 that is best served now. |
1da177e4 | 651 | * We choose the request that is closest to the head right now. Distance |
e8a99053 | 652 | * behind the head is penalized and only allowed to a certain extent. |
1da177e4 | 653 | */ |
5e705374 | 654 | static struct request * |
cf7c25cf | 655 | cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2, sector_t last) |
1da177e4 | 656 | { |
cf7c25cf | 657 | sector_t s1, s2, d1 = 0, d2 = 0; |
1da177e4 | 658 | unsigned long back_max; |
e8a99053 AM |
659 | #define CFQ_RQ1_WRAP 0x01 /* request 1 wraps */ |
660 | #define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */ | |
661 | unsigned wrap = 0; /* bit mask: requests behind the disk head? */ | |
1da177e4 | 662 | |
5e705374 JA |
663 | if (rq1 == NULL || rq1 == rq2) |
664 | return rq2; | |
665 | if (rq2 == NULL) | |
666 | return rq1; | |
9c2c38a1 | 667 | |
5e705374 JA |
668 | if (rq_is_sync(rq1) && !rq_is_sync(rq2)) |
669 | return rq1; | |
670 | else if (rq_is_sync(rq2) && !rq_is_sync(rq1)) | |
671 | return rq2; | |
7b6d91da | 672 | if ((rq1->cmd_flags & REQ_META) && !(rq2->cmd_flags & REQ_META)) |
374f84ac | 673 | return rq1; |
7b6d91da CH |
674 | else if ((rq2->cmd_flags & REQ_META) && |
675 | !(rq1->cmd_flags & REQ_META)) | |
374f84ac | 676 | return rq2; |
1da177e4 | 677 | |
83096ebf TH |
678 | s1 = blk_rq_pos(rq1); |
679 | s2 = blk_rq_pos(rq2); | |
1da177e4 | 680 | |
1da177e4 LT |
681 | /* |
682 | * by definition, 1KiB is 2 sectors | |
683 | */ | |
684 | back_max = cfqd->cfq_back_max * 2; | |
685 | ||
686 | /* | |
687 | * Strict one way elevator _except_ in the case where we allow | |
688 | * short backward seeks which are biased as twice the cost of a | |
689 | * similar forward seek. | |
690 | */ | |
691 | if (s1 >= last) | |
692 | d1 = s1 - last; | |
693 | else if (s1 + back_max >= last) | |
694 | d1 = (last - s1) * cfqd->cfq_back_penalty; | |
695 | else | |
e8a99053 | 696 | wrap |= CFQ_RQ1_WRAP; |
1da177e4 LT |
697 | |
698 | if (s2 >= last) | |
699 | d2 = s2 - last; | |
700 | else if (s2 + back_max >= last) | |
701 | d2 = (last - s2) * cfqd->cfq_back_penalty; | |
702 | else | |
e8a99053 | 703 | wrap |= CFQ_RQ2_WRAP; |
1da177e4 LT |
704 | |
705 | /* Found required data */ | |
e8a99053 AM |
706 | |
707 | /* | |
708 | * By doing switch() on the bit mask "wrap" we avoid having to | |
709 | * check two variables for all permutations: --> faster! | |
710 | */ | |
711 | switch (wrap) { | |
5e705374 | 712 | case 0: /* common case for CFQ: rq1 and rq2 not wrapped */ |
e8a99053 | 713 | if (d1 < d2) |
5e705374 | 714 | return rq1; |
e8a99053 | 715 | else if (d2 < d1) |
5e705374 | 716 | return rq2; |
e8a99053 AM |
717 | else { |
718 | if (s1 >= s2) | |
5e705374 | 719 | return rq1; |
e8a99053 | 720 | else |
5e705374 | 721 | return rq2; |
e8a99053 | 722 | } |
1da177e4 | 723 | |
e8a99053 | 724 | case CFQ_RQ2_WRAP: |
5e705374 | 725 | return rq1; |
e8a99053 | 726 | case CFQ_RQ1_WRAP: |
5e705374 JA |
727 | return rq2; |
728 | case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both rqs wrapped */ | |
e8a99053 AM |
729 | default: |
730 | /* | |
731 | * Since both rqs are wrapped, | |
732 | * start with the one that's further behind head | |
733 | * (--> only *one* back seek required), | |
734 | * since back seek takes more time than forward. | |
735 | */ | |
736 | if (s1 <= s2) | |
5e705374 | 737 | return rq1; |
1da177e4 | 738 | else |
5e705374 | 739 | return rq2; |
1da177e4 LT |
740 | } |
741 | } | |
742 | ||
498d3aa2 JA |
743 | /* |
744 | * The below is leftmost cache rbtree addon | |
745 | */ | |
0871714e | 746 | static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root) |
cc09e299 | 747 | { |
615f0259 VG |
748 | /* Service tree is empty */ |
749 | if (!root->count) | |
750 | return NULL; | |
751 | ||
cc09e299 JA |
752 | if (!root->left) |
753 | root->left = rb_first(&root->rb); | |
754 | ||
0871714e JA |
755 | if (root->left) |
756 | return rb_entry(root->left, struct cfq_queue, rb_node); | |
757 | ||
758 | return NULL; | |
cc09e299 JA |
759 | } |
760 | ||
1fa8f6d6 VG |
761 | static struct cfq_group *cfq_rb_first_group(struct cfq_rb_root *root) |
762 | { | |
763 | if (!root->left) | |
764 | root->left = rb_first(&root->rb); | |
765 | ||
766 | if (root->left) | |
767 | return rb_entry_cfqg(root->left); | |
768 | ||
769 | return NULL; | |
770 | } | |
771 | ||
a36e71f9 JA |
772 | static void rb_erase_init(struct rb_node *n, struct rb_root *root) |
773 | { | |
774 | rb_erase(n, root); | |
775 | RB_CLEAR_NODE(n); | |
776 | } | |
777 | ||
cc09e299 JA |
778 | static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root) |
779 | { | |
780 | if (root->left == n) | |
781 | root->left = NULL; | |
a36e71f9 | 782 | rb_erase_init(n, &root->rb); |
aa6f6a3d | 783 | --root->count; |
cc09e299 JA |
784 | } |
785 | ||
1da177e4 LT |
786 | /* |
787 | * would be nice to take fifo expire time into account as well | |
788 | */ | |
5e705374 JA |
789 | static struct request * |
790 | cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
791 | struct request *last) | |
1da177e4 | 792 | { |
21183b07 JA |
793 | struct rb_node *rbnext = rb_next(&last->rb_node); |
794 | struct rb_node *rbprev = rb_prev(&last->rb_node); | |
5e705374 | 795 | struct request *next = NULL, *prev = NULL; |
1da177e4 | 796 | |
21183b07 | 797 | BUG_ON(RB_EMPTY_NODE(&last->rb_node)); |
1da177e4 LT |
798 | |
799 | if (rbprev) | |
5e705374 | 800 | prev = rb_entry_rq(rbprev); |
1da177e4 | 801 | |
21183b07 | 802 | if (rbnext) |
5e705374 | 803 | next = rb_entry_rq(rbnext); |
21183b07 JA |
804 | else { |
805 | rbnext = rb_first(&cfqq->sort_list); | |
806 | if (rbnext && rbnext != &last->rb_node) | |
5e705374 | 807 | next = rb_entry_rq(rbnext); |
21183b07 | 808 | } |
1da177e4 | 809 | |
cf7c25cf | 810 | return cfq_choose_req(cfqd, next, prev, blk_rq_pos(last)); |
1da177e4 LT |
811 | } |
812 | ||
d9e7620e JA |
813 | static unsigned long cfq_slice_offset(struct cfq_data *cfqd, |
814 | struct cfq_queue *cfqq) | |
1da177e4 | 815 | { |
d9e7620e JA |
816 | /* |
817 | * just an approximation, should be ok. | |
818 | */ | |
cdb16e8f | 819 | return (cfqq->cfqg->nr_cfqq - 1) * (cfq_prio_slice(cfqd, 1, 0) - |
464191c6 | 820 | cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio)); |
d9e7620e JA |
821 | } |
822 | ||
1fa8f6d6 VG |
823 | static inline s64 |
824 | cfqg_key(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
825 | { | |
826 | return cfqg->vdisktime - st->min_vdisktime; | |
827 | } | |
828 | ||
829 | static void | |
830 | __cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
831 | { | |
832 | struct rb_node **node = &st->rb.rb_node; | |
833 | struct rb_node *parent = NULL; | |
834 | struct cfq_group *__cfqg; | |
835 | s64 key = cfqg_key(st, cfqg); | |
836 | int left = 1; | |
837 | ||
838 | while (*node != NULL) { | |
839 | parent = *node; | |
840 | __cfqg = rb_entry_cfqg(parent); | |
841 | ||
842 | if (key < cfqg_key(st, __cfqg)) | |
843 | node = &parent->rb_left; | |
844 | else { | |
845 | node = &parent->rb_right; | |
846 | left = 0; | |
847 | } | |
848 | } | |
849 | ||
850 | if (left) | |
851 | st->left = &cfqg->rb_node; | |
852 | ||
853 | rb_link_node(&cfqg->rb_node, parent, node); | |
854 | rb_insert_color(&cfqg->rb_node, &st->rb); | |
855 | } | |
856 | ||
857 | static void | |
8184f93e JT |
858 | cfq_update_group_weight(struct cfq_group *cfqg) |
859 | { | |
860 | BUG_ON(!RB_EMPTY_NODE(&cfqg->rb_node)); | |
861 | if (cfqg->needs_update) { | |
862 | cfqg->weight = cfqg->new_weight; | |
863 | cfqg->needs_update = false; | |
864 | } | |
865 | } | |
866 | ||
867 | static void | |
868 | cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
869 | { | |
870 | BUG_ON(!RB_EMPTY_NODE(&cfqg->rb_node)); | |
871 | ||
872 | cfq_update_group_weight(cfqg); | |
873 | __cfq_group_service_tree_add(st, cfqg); | |
874 | st->total_weight += cfqg->weight; | |
875 | } | |
876 | ||
877 | static void | |
878 | cfq_group_notify_queue_add(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
1fa8f6d6 VG |
879 | { |
880 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
881 | struct cfq_group *__cfqg; | |
882 | struct rb_node *n; | |
883 | ||
884 | cfqg->nr_cfqq++; | |
760701bf | 885 | if (!RB_EMPTY_NODE(&cfqg->rb_node)) |
1fa8f6d6 VG |
886 | return; |
887 | ||
888 | /* | |
889 | * Currently put the group at the end. Later implement something | |
890 | * so that groups get lesser vtime based on their weights, so that | |
25985edc | 891 | * if group does not loose all if it was not continuously backlogged. |
1fa8f6d6 VG |
892 | */ |
893 | n = rb_last(&st->rb); | |
894 | if (n) { | |
895 | __cfqg = rb_entry_cfqg(n); | |
896 | cfqg->vdisktime = __cfqg->vdisktime + CFQ_IDLE_DELAY; | |
897 | } else | |
898 | cfqg->vdisktime = st->min_vdisktime; | |
8184f93e JT |
899 | cfq_group_service_tree_add(st, cfqg); |
900 | } | |
1fa8f6d6 | 901 | |
8184f93e JT |
902 | static void |
903 | cfq_group_service_tree_del(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
904 | { | |
905 | st->total_weight -= cfqg->weight; | |
906 | if (!RB_EMPTY_NODE(&cfqg->rb_node)) | |
907 | cfq_rb_erase(&cfqg->rb_node, st); | |
1fa8f6d6 VG |
908 | } |
909 | ||
910 | static void | |
8184f93e | 911 | cfq_group_notify_queue_del(struct cfq_data *cfqd, struct cfq_group *cfqg) |
1fa8f6d6 VG |
912 | { |
913 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
914 | ||
915 | BUG_ON(cfqg->nr_cfqq < 1); | |
916 | cfqg->nr_cfqq--; | |
25bc6b07 | 917 | |
1fa8f6d6 VG |
918 | /* If there are other cfq queues under this group, don't delete it */ |
919 | if (cfqg->nr_cfqq) | |
920 | return; | |
921 | ||
2868ef7b | 922 | cfq_log_cfqg(cfqd, cfqg, "del_from_rr group"); |
8184f93e | 923 | cfq_group_service_tree_del(st, cfqg); |
dae739eb | 924 | cfqg->saved_workload_slice = 0; |
e98ef89b | 925 | cfq_blkiocg_update_dequeue_stats(&cfqg->blkg, 1); |
dae739eb VG |
926 | } |
927 | ||
167400d3 JT |
928 | static inline unsigned int cfq_cfqq_slice_usage(struct cfq_queue *cfqq, |
929 | unsigned int *unaccounted_time) | |
dae739eb | 930 | { |
f75edf2d | 931 | unsigned int slice_used; |
dae739eb VG |
932 | |
933 | /* | |
934 | * Queue got expired before even a single request completed or | |
935 | * got expired immediately after first request completion. | |
936 | */ | |
937 | if (!cfqq->slice_start || cfqq->slice_start == jiffies) { | |
938 | /* | |
939 | * Also charge the seek time incurred to the group, otherwise | |
940 | * if there are mutiple queues in the group, each can dispatch | |
941 | * a single request on seeky media and cause lots of seek time | |
942 | * and group will never know it. | |
943 | */ | |
944 | slice_used = max_t(unsigned, (jiffies - cfqq->dispatch_start), | |
945 | 1); | |
946 | } else { | |
947 | slice_used = jiffies - cfqq->slice_start; | |
167400d3 JT |
948 | if (slice_used > cfqq->allocated_slice) { |
949 | *unaccounted_time = slice_used - cfqq->allocated_slice; | |
f75edf2d | 950 | slice_used = cfqq->allocated_slice; |
167400d3 JT |
951 | } |
952 | if (time_after(cfqq->slice_start, cfqq->dispatch_start)) | |
953 | *unaccounted_time += cfqq->slice_start - | |
954 | cfqq->dispatch_start; | |
dae739eb VG |
955 | } |
956 | ||
dae739eb VG |
957 | return slice_used; |
958 | } | |
959 | ||
960 | static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg, | |
e5ff082e | 961 | struct cfq_queue *cfqq) |
dae739eb VG |
962 | { |
963 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
167400d3 | 964 | unsigned int used_sl, charge, unaccounted_sl = 0; |
f26bd1f0 VG |
965 | int nr_sync = cfqg->nr_cfqq - cfqg_busy_async_queues(cfqd, cfqg) |
966 | - cfqg->service_tree_idle.count; | |
967 | ||
968 | BUG_ON(nr_sync < 0); | |
167400d3 | 969 | used_sl = charge = cfq_cfqq_slice_usage(cfqq, &unaccounted_sl); |
dae739eb | 970 | |
02b35081 VG |
971 | if (iops_mode(cfqd)) |
972 | charge = cfqq->slice_dispatch; | |
973 | else if (!cfq_cfqq_sync(cfqq) && !nr_sync) | |
974 | charge = cfqq->allocated_slice; | |
dae739eb VG |
975 | |
976 | /* Can't update vdisktime while group is on service tree */ | |
8184f93e | 977 | cfq_group_service_tree_del(st, cfqg); |
02b35081 | 978 | cfqg->vdisktime += cfq_scale_slice(charge, cfqg); |
8184f93e JT |
979 | /* If a new weight was requested, update now, off tree */ |
980 | cfq_group_service_tree_add(st, cfqg); | |
dae739eb VG |
981 | |
982 | /* This group is being expired. Save the context */ | |
983 | if (time_after(cfqd->workload_expires, jiffies)) { | |
984 | cfqg->saved_workload_slice = cfqd->workload_expires | |
985 | - jiffies; | |
986 | cfqg->saved_workload = cfqd->serving_type; | |
987 | cfqg->saved_serving_prio = cfqd->serving_prio; | |
988 | } else | |
989 | cfqg->saved_workload_slice = 0; | |
2868ef7b VG |
990 | |
991 | cfq_log_cfqg(cfqd, cfqg, "served: vt=%llu min_vt=%llu", cfqg->vdisktime, | |
992 | st->min_vdisktime); | |
c4e7893e VG |
993 | cfq_log_cfqq(cfqq->cfqd, cfqq, "sl_used=%u disp=%u charge=%u iops=%u" |
994 | " sect=%u", used_sl, cfqq->slice_dispatch, charge, | |
995 | iops_mode(cfqd), cfqq->nr_sectors); | |
167400d3 JT |
996 | cfq_blkiocg_update_timeslice_used(&cfqg->blkg, used_sl, |
997 | unaccounted_sl); | |
e98ef89b | 998 | cfq_blkiocg_set_start_empty_time(&cfqg->blkg); |
1fa8f6d6 VG |
999 | } |
1000 | ||
25fb5169 VG |
1001 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
1002 | static inline struct cfq_group *cfqg_of_blkg(struct blkio_group *blkg) | |
1003 | { | |
1004 | if (blkg) | |
1005 | return container_of(blkg, struct cfq_group, blkg); | |
1006 | return NULL; | |
1007 | } | |
1008 | ||
fe071437 VG |
1009 | void cfq_update_blkio_group_weight(void *key, struct blkio_group *blkg, |
1010 | unsigned int weight) | |
f8d461d6 | 1011 | { |
8184f93e JT |
1012 | struct cfq_group *cfqg = cfqg_of_blkg(blkg); |
1013 | cfqg->new_weight = weight; | |
1014 | cfqg->needs_update = true; | |
f8d461d6 VG |
1015 | } |
1016 | ||
25fb5169 VG |
1017 | static struct cfq_group * |
1018 | cfq_find_alloc_cfqg(struct cfq_data *cfqd, struct cgroup *cgroup, int create) | |
1019 | { | |
1020 | struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup); | |
1021 | struct cfq_group *cfqg = NULL; | |
1022 | void *key = cfqd; | |
1023 | int i, j; | |
1024 | struct cfq_rb_root *st; | |
22084190 VG |
1025 | struct backing_dev_info *bdi = &cfqd->queue->backing_dev_info; |
1026 | unsigned int major, minor; | |
25fb5169 | 1027 | |
25fb5169 | 1028 | cfqg = cfqg_of_blkg(blkiocg_lookup_group(blkcg, key)); |
a74b2ada RB |
1029 | if (cfqg && !cfqg->blkg.dev && bdi->dev && dev_name(bdi->dev)) { |
1030 | sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor); | |
1031 | cfqg->blkg.dev = MKDEV(major, minor); | |
1032 | goto done; | |
1033 | } | |
25fb5169 VG |
1034 | if (cfqg || !create) |
1035 | goto done; | |
1036 | ||
1037 | cfqg = kzalloc_node(sizeof(*cfqg), GFP_ATOMIC, cfqd->queue->node); | |
1038 | if (!cfqg) | |
1039 | goto done; | |
1040 | ||
25fb5169 VG |
1041 | for_each_cfqg_st(cfqg, i, j, st) |
1042 | *st = CFQ_RB_ROOT; | |
1043 | RB_CLEAR_NODE(&cfqg->rb_node); | |
1044 | ||
b1c35769 VG |
1045 | /* |
1046 | * Take the initial reference that will be released on destroy | |
1047 | * This can be thought of a joint reference by cgroup and | |
1048 | * elevator which will be dropped by either elevator exit | |
1049 | * or cgroup deletion path depending on who is exiting first. | |
1050 | */ | |
329a6781 | 1051 | cfqg->ref = 1; |
b1c35769 | 1052 | |
180be2a0 VG |
1053 | /* |
1054 | * Add group onto cgroup list. It might happen that bdi->dev is | |
b595076a | 1055 | * not initialized yet. Initialize this new group without major |
180be2a0 VG |
1056 | * and minor info and this info will be filled in once a new thread |
1057 | * comes for IO. See code above. | |
1058 | */ | |
1059 | if (bdi->dev) { | |
1060 | sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor); | |
1061 | cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg, (void *)cfqd, | |
22084190 | 1062 | MKDEV(major, minor)); |
180be2a0 VG |
1063 | } else |
1064 | cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg, (void *)cfqd, | |
1065 | 0); | |
1066 | ||
34d0f179 | 1067 | cfqg->weight = blkcg_get_weight(blkcg, cfqg->blkg.dev); |
25fb5169 VG |
1068 | |
1069 | /* Add group on cfqd list */ | |
1070 | hlist_add_head(&cfqg->cfqd_node, &cfqd->cfqg_list); | |
1071 | ||
1072 | done: | |
25fb5169 VG |
1073 | return cfqg; |
1074 | } | |
1075 | ||
1076 | /* | |
1077 | * Search for the cfq group current task belongs to. If create = 1, then also | |
1078 | * create the cfq group if it does not exist. request_queue lock must be held. | |
1079 | */ | |
1080 | static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd, int create) | |
1081 | { | |
1082 | struct cgroup *cgroup; | |
1083 | struct cfq_group *cfqg = NULL; | |
1084 | ||
1085 | rcu_read_lock(); | |
1086 | cgroup = task_cgroup(current, blkio_subsys_id); | |
1087 | cfqg = cfq_find_alloc_cfqg(cfqd, cgroup, create); | |
1088 | if (!cfqg && create) | |
1089 | cfqg = &cfqd->root_group; | |
1090 | rcu_read_unlock(); | |
1091 | return cfqg; | |
1092 | } | |
1093 | ||
7f1dc8a2 VG |
1094 | static inline struct cfq_group *cfq_ref_get_cfqg(struct cfq_group *cfqg) |
1095 | { | |
329a6781 | 1096 | cfqg->ref++; |
7f1dc8a2 VG |
1097 | return cfqg; |
1098 | } | |
1099 | ||
25fb5169 VG |
1100 | static void cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) |
1101 | { | |
1102 | /* Currently, all async queues are mapped to root group */ | |
1103 | if (!cfq_cfqq_sync(cfqq)) | |
1104 | cfqg = &cfqq->cfqd->root_group; | |
1105 | ||
1106 | cfqq->cfqg = cfqg; | |
b1c35769 | 1107 | /* cfqq reference on cfqg */ |
329a6781 | 1108 | cfqq->cfqg->ref++; |
b1c35769 VG |
1109 | } |
1110 | ||
1111 | static void cfq_put_cfqg(struct cfq_group *cfqg) | |
1112 | { | |
1113 | struct cfq_rb_root *st; | |
1114 | int i, j; | |
1115 | ||
329a6781 SL |
1116 | BUG_ON(cfqg->ref <= 0); |
1117 | cfqg->ref--; | |
1118 | if (cfqg->ref) | |
b1c35769 VG |
1119 | return; |
1120 | for_each_cfqg_st(cfqg, i, j, st) | |
b54ce60e | 1121 | BUG_ON(!RB_EMPTY_ROOT(&st->rb)); |
b1c35769 VG |
1122 | kfree(cfqg); |
1123 | } | |
1124 | ||
1125 | static void cfq_destroy_cfqg(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
1126 | { | |
1127 | /* Something wrong if we are trying to remove same group twice */ | |
1128 | BUG_ON(hlist_unhashed(&cfqg->cfqd_node)); | |
1129 | ||
1130 | hlist_del_init(&cfqg->cfqd_node); | |
1131 | ||
1132 | /* | |
1133 | * Put the reference taken at the time of creation so that when all | |
1134 | * queues are gone, group can be destroyed. | |
1135 | */ | |
1136 | cfq_put_cfqg(cfqg); | |
1137 | } | |
1138 | ||
1139 | static void cfq_release_cfq_groups(struct cfq_data *cfqd) | |
1140 | { | |
1141 | struct hlist_node *pos, *n; | |
1142 | struct cfq_group *cfqg; | |
1143 | ||
1144 | hlist_for_each_entry_safe(cfqg, pos, n, &cfqd->cfqg_list, cfqd_node) { | |
1145 | /* | |
1146 | * If cgroup removal path got to blk_group first and removed | |
1147 | * it from cgroup list, then it will take care of destroying | |
1148 | * cfqg also. | |
1149 | */ | |
e98ef89b | 1150 | if (!cfq_blkiocg_del_blkio_group(&cfqg->blkg)) |
b1c35769 VG |
1151 | cfq_destroy_cfqg(cfqd, cfqg); |
1152 | } | |
25fb5169 | 1153 | } |
b1c35769 VG |
1154 | |
1155 | /* | |
1156 | * Blk cgroup controller notification saying that blkio_group object is being | |
1157 | * delinked as associated cgroup object is going away. That also means that | |
1158 | * no new IO will come in this group. So get rid of this group as soon as | |
1159 | * any pending IO in the group is finished. | |
1160 | * | |
1161 | * This function is called under rcu_read_lock(). key is the rcu protected | |
1162 | * pointer. That means "key" is a valid cfq_data pointer as long as we are rcu | |
1163 | * read lock. | |
1164 | * | |
1165 | * "key" was fetched from blkio_group under blkio_cgroup->lock. That means | |
1166 | * it should not be NULL as even if elevator was exiting, cgroup deltion | |
1167 | * path got to it first. | |
1168 | */ | |
1169 | void cfq_unlink_blkio_group(void *key, struct blkio_group *blkg) | |
1170 | { | |
1171 | unsigned long flags; | |
1172 | struct cfq_data *cfqd = key; | |
1173 | ||
1174 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
1175 | cfq_destroy_cfqg(cfqd, cfqg_of_blkg(blkg)); | |
1176 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
1177 | } | |
1178 | ||
25fb5169 VG |
1179 | #else /* GROUP_IOSCHED */ |
1180 | static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd, int create) | |
1181 | { | |
1182 | return &cfqd->root_group; | |
1183 | } | |
7f1dc8a2 VG |
1184 | |
1185 | static inline struct cfq_group *cfq_ref_get_cfqg(struct cfq_group *cfqg) | |
1186 | { | |
50eaeb32 | 1187 | return cfqg; |
7f1dc8a2 VG |
1188 | } |
1189 | ||
25fb5169 VG |
1190 | static inline void |
1191 | cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) { | |
1192 | cfqq->cfqg = cfqg; | |
1193 | } | |
1194 | ||
b1c35769 VG |
1195 | static void cfq_release_cfq_groups(struct cfq_data *cfqd) {} |
1196 | static inline void cfq_put_cfqg(struct cfq_group *cfqg) {} | |
1197 | ||
25fb5169 VG |
1198 | #endif /* GROUP_IOSCHED */ |
1199 | ||
498d3aa2 | 1200 | /* |
c0324a02 | 1201 | * The cfqd->service_trees holds all pending cfq_queue's that have |
498d3aa2 JA |
1202 | * requests waiting to be processed. It is sorted in the order that |
1203 | * we will service the queues. | |
1204 | */ | |
a36e71f9 | 1205 | static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
a6151c3a | 1206 | bool add_front) |
d9e7620e | 1207 | { |
0871714e JA |
1208 | struct rb_node **p, *parent; |
1209 | struct cfq_queue *__cfqq; | |
d9e7620e | 1210 | unsigned long rb_key; |
c0324a02 | 1211 | struct cfq_rb_root *service_tree; |
498d3aa2 | 1212 | int left; |
dae739eb | 1213 | int new_cfqq = 1; |
ae30c286 VG |
1214 | int group_changed = 0; |
1215 | ||
cdb16e8f | 1216 | service_tree = service_tree_for(cfqq->cfqg, cfqq_prio(cfqq), |
65b32a57 | 1217 | cfqq_type(cfqq)); |
0871714e JA |
1218 | if (cfq_class_idle(cfqq)) { |
1219 | rb_key = CFQ_IDLE_DELAY; | |
aa6f6a3d | 1220 | parent = rb_last(&service_tree->rb); |
0871714e JA |
1221 | if (parent && parent != &cfqq->rb_node) { |
1222 | __cfqq = rb_entry(parent, struct cfq_queue, rb_node); | |
1223 | rb_key += __cfqq->rb_key; | |
1224 | } else | |
1225 | rb_key += jiffies; | |
1226 | } else if (!add_front) { | |
b9c8946b JA |
1227 | /* |
1228 | * Get our rb key offset. Subtract any residual slice | |
1229 | * value carried from last service. A negative resid | |
1230 | * count indicates slice overrun, and this should position | |
1231 | * the next service time further away in the tree. | |
1232 | */ | |
edd75ffd | 1233 | rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies; |
b9c8946b | 1234 | rb_key -= cfqq->slice_resid; |
edd75ffd | 1235 | cfqq->slice_resid = 0; |
48e025e6 CZ |
1236 | } else { |
1237 | rb_key = -HZ; | |
aa6f6a3d | 1238 | __cfqq = cfq_rb_first(service_tree); |
48e025e6 CZ |
1239 | rb_key += __cfqq ? __cfqq->rb_key : jiffies; |
1240 | } | |
1da177e4 | 1241 | |
d9e7620e | 1242 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) { |
dae739eb | 1243 | new_cfqq = 0; |
99f9628a | 1244 | /* |
d9e7620e | 1245 | * same position, nothing more to do |
99f9628a | 1246 | */ |
c0324a02 CZ |
1247 | if (rb_key == cfqq->rb_key && |
1248 | cfqq->service_tree == service_tree) | |
d9e7620e | 1249 | return; |
1da177e4 | 1250 | |
aa6f6a3d CZ |
1251 | cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree); |
1252 | cfqq->service_tree = NULL; | |
1da177e4 | 1253 | } |
d9e7620e | 1254 | |
498d3aa2 | 1255 | left = 1; |
0871714e | 1256 | parent = NULL; |
aa6f6a3d CZ |
1257 | cfqq->service_tree = service_tree; |
1258 | p = &service_tree->rb.rb_node; | |
d9e7620e | 1259 | while (*p) { |
67060e37 | 1260 | struct rb_node **n; |
cc09e299 | 1261 | |
d9e7620e JA |
1262 | parent = *p; |
1263 | __cfqq = rb_entry(parent, struct cfq_queue, rb_node); | |
1264 | ||
0c534e0a | 1265 | /* |
c0324a02 | 1266 | * sort by key, that represents service time. |
0c534e0a | 1267 | */ |
c0324a02 | 1268 | if (time_before(rb_key, __cfqq->rb_key)) |
67060e37 | 1269 | n = &(*p)->rb_left; |
c0324a02 | 1270 | else { |
67060e37 | 1271 | n = &(*p)->rb_right; |
cc09e299 | 1272 | left = 0; |
c0324a02 | 1273 | } |
67060e37 JA |
1274 | |
1275 | p = n; | |
d9e7620e JA |
1276 | } |
1277 | ||
cc09e299 | 1278 | if (left) |
aa6f6a3d | 1279 | service_tree->left = &cfqq->rb_node; |
cc09e299 | 1280 | |
d9e7620e JA |
1281 | cfqq->rb_key = rb_key; |
1282 | rb_link_node(&cfqq->rb_node, parent, p); | |
aa6f6a3d CZ |
1283 | rb_insert_color(&cfqq->rb_node, &service_tree->rb); |
1284 | service_tree->count++; | |
ae30c286 | 1285 | if ((add_front || !new_cfqq) && !group_changed) |
dae739eb | 1286 | return; |
8184f93e | 1287 | cfq_group_notify_queue_add(cfqd, cfqq->cfqg); |
1da177e4 LT |
1288 | } |
1289 | ||
a36e71f9 | 1290 | static struct cfq_queue * |
f2d1f0ae JA |
1291 | cfq_prio_tree_lookup(struct cfq_data *cfqd, struct rb_root *root, |
1292 | sector_t sector, struct rb_node **ret_parent, | |
1293 | struct rb_node ***rb_link) | |
a36e71f9 | 1294 | { |
a36e71f9 JA |
1295 | struct rb_node **p, *parent; |
1296 | struct cfq_queue *cfqq = NULL; | |
1297 | ||
1298 | parent = NULL; | |
1299 | p = &root->rb_node; | |
1300 | while (*p) { | |
1301 | struct rb_node **n; | |
1302 | ||
1303 | parent = *p; | |
1304 | cfqq = rb_entry(parent, struct cfq_queue, p_node); | |
1305 | ||
1306 | /* | |
1307 | * Sort strictly based on sector. Smallest to the left, | |
1308 | * largest to the right. | |
1309 | */ | |
2e46e8b2 | 1310 | if (sector > blk_rq_pos(cfqq->next_rq)) |
a36e71f9 | 1311 | n = &(*p)->rb_right; |
2e46e8b2 | 1312 | else if (sector < blk_rq_pos(cfqq->next_rq)) |
a36e71f9 JA |
1313 | n = &(*p)->rb_left; |
1314 | else | |
1315 | break; | |
1316 | p = n; | |
3ac6c9f8 | 1317 | cfqq = NULL; |
a36e71f9 JA |
1318 | } |
1319 | ||
1320 | *ret_parent = parent; | |
1321 | if (rb_link) | |
1322 | *rb_link = p; | |
3ac6c9f8 | 1323 | return cfqq; |
a36e71f9 JA |
1324 | } |
1325 | ||
1326 | static void cfq_prio_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1327 | { | |
a36e71f9 JA |
1328 | struct rb_node **p, *parent; |
1329 | struct cfq_queue *__cfqq; | |
1330 | ||
f2d1f0ae JA |
1331 | if (cfqq->p_root) { |
1332 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
1333 | cfqq->p_root = NULL; | |
1334 | } | |
a36e71f9 JA |
1335 | |
1336 | if (cfq_class_idle(cfqq)) | |
1337 | return; | |
1338 | if (!cfqq->next_rq) | |
1339 | return; | |
1340 | ||
f2d1f0ae | 1341 | cfqq->p_root = &cfqd->prio_trees[cfqq->org_ioprio]; |
2e46e8b2 TH |
1342 | __cfqq = cfq_prio_tree_lookup(cfqd, cfqq->p_root, |
1343 | blk_rq_pos(cfqq->next_rq), &parent, &p); | |
3ac6c9f8 JA |
1344 | if (!__cfqq) { |
1345 | rb_link_node(&cfqq->p_node, parent, p); | |
f2d1f0ae JA |
1346 | rb_insert_color(&cfqq->p_node, cfqq->p_root); |
1347 | } else | |
1348 | cfqq->p_root = NULL; | |
a36e71f9 JA |
1349 | } |
1350 | ||
498d3aa2 JA |
1351 | /* |
1352 | * Update cfqq's position in the service tree. | |
1353 | */ | |
edd75ffd | 1354 | static void cfq_resort_rr_list(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
6d048f53 | 1355 | { |
6d048f53 JA |
1356 | /* |
1357 | * Resorting requires the cfqq to be on the RR list already. | |
1358 | */ | |
a36e71f9 | 1359 | if (cfq_cfqq_on_rr(cfqq)) { |
edd75ffd | 1360 | cfq_service_tree_add(cfqd, cfqq, 0); |
a36e71f9 JA |
1361 | cfq_prio_tree_add(cfqd, cfqq); |
1362 | } | |
6d048f53 JA |
1363 | } |
1364 | ||
1da177e4 LT |
1365 | /* |
1366 | * add to busy list of queues for service, trying to be fair in ordering | |
22e2c507 | 1367 | * the pending list according to last request service |
1da177e4 | 1368 | */ |
febffd61 | 1369 | static void cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 1370 | { |
7b679138 | 1371 | cfq_log_cfqq(cfqd, cfqq, "add_to_rr"); |
3b18152c JA |
1372 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
1373 | cfq_mark_cfqq_on_rr(cfqq); | |
1da177e4 | 1374 | cfqd->busy_queues++; |
ef8a41df SL |
1375 | if (cfq_cfqq_sync(cfqq)) |
1376 | cfqd->busy_sync_queues++; | |
1da177e4 | 1377 | |
edd75ffd | 1378 | cfq_resort_rr_list(cfqd, cfqq); |
1da177e4 LT |
1379 | } |
1380 | ||
498d3aa2 JA |
1381 | /* |
1382 | * Called when the cfqq no longer has requests pending, remove it from | |
1383 | * the service tree. | |
1384 | */ | |
febffd61 | 1385 | static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 1386 | { |
7b679138 | 1387 | cfq_log_cfqq(cfqd, cfqq, "del_from_rr"); |
3b18152c JA |
1388 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
1389 | cfq_clear_cfqq_on_rr(cfqq); | |
1da177e4 | 1390 | |
aa6f6a3d CZ |
1391 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) { |
1392 | cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree); | |
1393 | cfqq->service_tree = NULL; | |
1394 | } | |
f2d1f0ae JA |
1395 | if (cfqq->p_root) { |
1396 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
1397 | cfqq->p_root = NULL; | |
1398 | } | |
d9e7620e | 1399 | |
8184f93e | 1400 | cfq_group_notify_queue_del(cfqd, cfqq->cfqg); |
1da177e4 LT |
1401 | BUG_ON(!cfqd->busy_queues); |
1402 | cfqd->busy_queues--; | |
ef8a41df SL |
1403 | if (cfq_cfqq_sync(cfqq)) |
1404 | cfqd->busy_sync_queues--; | |
1da177e4 LT |
1405 | } |
1406 | ||
1407 | /* | |
1408 | * rb tree support functions | |
1409 | */ | |
febffd61 | 1410 | static void cfq_del_rq_rb(struct request *rq) |
1da177e4 | 1411 | { |
5e705374 | 1412 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
5e705374 | 1413 | const int sync = rq_is_sync(rq); |
1da177e4 | 1414 | |
b4878f24 JA |
1415 | BUG_ON(!cfqq->queued[sync]); |
1416 | cfqq->queued[sync]--; | |
1da177e4 | 1417 | |
5e705374 | 1418 | elv_rb_del(&cfqq->sort_list, rq); |
1da177e4 | 1419 | |
f04a6424 VG |
1420 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) { |
1421 | /* | |
1422 | * Queue will be deleted from service tree when we actually | |
1423 | * expire it later. Right now just remove it from prio tree | |
1424 | * as it is empty. | |
1425 | */ | |
1426 | if (cfqq->p_root) { | |
1427 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
1428 | cfqq->p_root = NULL; | |
1429 | } | |
1430 | } | |
1da177e4 LT |
1431 | } |
1432 | ||
5e705374 | 1433 | static void cfq_add_rq_rb(struct request *rq) |
1da177e4 | 1434 | { |
5e705374 | 1435 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
1da177e4 | 1436 | struct cfq_data *cfqd = cfqq->cfqd; |
a36e71f9 | 1437 | struct request *__alias, *prev; |
1da177e4 | 1438 | |
5380a101 | 1439 | cfqq->queued[rq_is_sync(rq)]++; |
1da177e4 LT |
1440 | |
1441 | /* | |
1442 | * looks a little odd, but the first insert might return an alias. | |
1443 | * if that happens, put the alias on the dispatch list | |
1444 | */ | |
21183b07 | 1445 | while ((__alias = elv_rb_add(&cfqq->sort_list, rq)) != NULL) |
5e705374 | 1446 | cfq_dispatch_insert(cfqd->queue, __alias); |
5fccbf61 JA |
1447 | |
1448 | if (!cfq_cfqq_on_rr(cfqq)) | |
1449 | cfq_add_cfqq_rr(cfqd, cfqq); | |
5044eed4 JA |
1450 | |
1451 | /* | |
1452 | * check if this request is a better next-serve candidate | |
1453 | */ | |
a36e71f9 | 1454 | prev = cfqq->next_rq; |
cf7c25cf | 1455 | cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq, cfqd->last_position); |
a36e71f9 JA |
1456 | |
1457 | /* | |
1458 | * adjust priority tree position, if ->next_rq changes | |
1459 | */ | |
1460 | if (prev != cfqq->next_rq) | |
1461 | cfq_prio_tree_add(cfqd, cfqq); | |
1462 | ||
5044eed4 | 1463 | BUG_ON(!cfqq->next_rq); |
1da177e4 LT |
1464 | } |
1465 | ||
febffd61 | 1466 | static void cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq) |
1da177e4 | 1467 | { |
5380a101 JA |
1468 | elv_rb_del(&cfqq->sort_list, rq); |
1469 | cfqq->queued[rq_is_sync(rq)]--; | |
e98ef89b VG |
1470 | cfq_blkiocg_update_io_remove_stats(&(RQ_CFQG(rq))->blkg, |
1471 | rq_data_dir(rq), rq_is_sync(rq)); | |
5e705374 | 1472 | cfq_add_rq_rb(rq); |
e98ef89b | 1473 | cfq_blkiocg_update_io_add_stats(&(RQ_CFQG(rq))->blkg, |
7f1dc8a2 VG |
1474 | &cfqq->cfqd->serving_group->blkg, rq_data_dir(rq), |
1475 | rq_is_sync(rq)); | |
1da177e4 LT |
1476 | } |
1477 | ||
206dc69b JA |
1478 | static struct request * |
1479 | cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio) | |
1da177e4 | 1480 | { |
206dc69b | 1481 | struct task_struct *tsk = current; |
91fac317 | 1482 | struct cfq_io_context *cic; |
206dc69b | 1483 | struct cfq_queue *cfqq; |
1da177e4 | 1484 | |
4ac845a2 | 1485 | cic = cfq_cic_lookup(cfqd, tsk->io_context); |
91fac317 VT |
1486 | if (!cic) |
1487 | return NULL; | |
1488 | ||
1489 | cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); | |
89850f7e JA |
1490 | if (cfqq) { |
1491 | sector_t sector = bio->bi_sector + bio_sectors(bio); | |
1492 | ||
21183b07 | 1493 | return elv_rb_find(&cfqq->sort_list, sector); |
89850f7e | 1494 | } |
1da177e4 | 1495 | |
1da177e4 LT |
1496 | return NULL; |
1497 | } | |
1498 | ||
165125e1 | 1499 | static void cfq_activate_request(struct request_queue *q, struct request *rq) |
1da177e4 | 1500 | { |
22e2c507 | 1501 | struct cfq_data *cfqd = q->elevator->elevator_data; |
3b18152c | 1502 | |
53c583d2 | 1503 | cfqd->rq_in_driver++; |
7b679138 | 1504 | cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "activate rq, drv=%d", |
53c583d2 | 1505 | cfqd->rq_in_driver); |
25776e35 | 1506 | |
5b93629b | 1507 | cfqd->last_position = blk_rq_pos(rq) + blk_rq_sectors(rq); |
1da177e4 LT |
1508 | } |
1509 | ||
165125e1 | 1510 | static void cfq_deactivate_request(struct request_queue *q, struct request *rq) |
1da177e4 | 1511 | { |
b4878f24 JA |
1512 | struct cfq_data *cfqd = q->elevator->elevator_data; |
1513 | ||
53c583d2 CZ |
1514 | WARN_ON(!cfqd->rq_in_driver); |
1515 | cfqd->rq_in_driver--; | |
7b679138 | 1516 | cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "deactivate rq, drv=%d", |
53c583d2 | 1517 | cfqd->rq_in_driver); |
1da177e4 LT |
1518 | } |
1519 | ||
b4878f24 | 1520 | static void cfq_remove_request(struct request *rq) |
1da177e4 | 1521 | { |
5e705374 | 1522 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
21183b07 | 1523 | |
5e705374 JA |
1524 | if (cfqq->next_rq == rq) |
1525 | cfqq->next_rq = cfq_find_next_rq(cfqq->cfqd, cfqq, rq); | |
1da177e4 | 1526 | |
b4878f24 | 1527 | list_del_init(&rq->queuelist); |
5e705374 | 1528 | cfq_del_rq_rb(rq); |
374f84ac | 1529 | |
45333d5a | 1530 | cfqq->cfqd->rq_queued--; |
e98ef89b VG |
1531 | cfq_blkiocg_update_io_remove_stats(&(RQ_CFQG(rq))->blkg, |
1532 | rq_data_dir(rq), rq_is_sync(rq)); | |
7b6d91da | 1533 | if (rq->cmd_flags & REQ_META) { |
374f84ac JA |
1534 | WARN_ON(!cfqq->meta_pending); |
1535 | cfqq->meta_pending--; | |
1536 | } | |
1da177e4 LT |
1537 | } |
1538 | ||
165125e1 JA |
1539 | static int cfq_merge(struct request_queue *q, struct request **req, |
1540 | struct bio *bio) | |
1da177e4 LT |
1541 | { |
1542 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1543 | struct request *__rq; | |
1da177e4 | 1544 | |
206dc69b | 1545 | __rq = cfq_find_rq_fmerge(cfqd, bio); |
22e2c507 | 1546 | if (__rq && elv_rq_merge_ok(__rq, bio)) { |
9817064b JA |
1547 | *req = __rq; |
1548 | return ELEVATOR_FRONT_MERGE; | |
1da177e4 LT |
1549 | } |
1550 | ||
1551 | return ELEVATOR_NO_MERGE; | |
1da177e4 LT |
1552 | } |
1553 | ||
165125e1 | 1554 | static void cfq_merged_request(struct request_queue *q, struct request *req, |
21183b07 | 1555 | int type) |
1da177e4 | 1556 | { |
21183b07 | 1557 | if (type == ELEVATOR_FRONT_MERGE) { |
5e705374 | 1558 | struct cfq_queue *cfqq = RQ_CFQQ(req); |
1da177e4 | 1559 | |
5e705374 | 1560 | cfq_reposition_rq_rb(cfqq, req); |
1da177e4 | 1561 | } |
1da177e4 LT |
1562 | } |
1563 | ||
812d4026 DS |
1564 | static void cfq_bio_merged(struct request_queue *q, struct request *req, |
1565 | struct bio *bio) | |
1566 | { | |
e98ef89b VG |
1567 | cfq_blkiocg_update_io_merged_stats(&(RQ_CFQG(req))->blkg, |
1568 | bio_data_dir(bio), cfq_bio_sync(bio)); | |
812d4026 DS |
1569 | } |
1570 | ||
1da177e4 | 1571 | static void |
165125e1 | 1572 | cfq_merged_requests(struct request_queue *q, struct request *rq, |
1da177e4 LT |
1573 | struct request *next) |
1574 | { | |
cf7c25cf | 1575 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 JA |
1576 | /* |
1577 | * reposition in fifo if next is older than rq | |
1578 | */ | |
1579 | if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && | |
30996f40 | 1580 | time_before(rq_fifo_time(next), rq_fifo_time(rq))) { |
22e2c507 | 1581 | list_move(&rq->queuelist, &next->queuelist); |
30996f40 JA |
1582 | rq_set_fifo_time(rq, rq_fifo_time(next)); |
1583 | } | |
22e2c507 | 1584 | |
cf7c25cf CZ |
1585 | if (cfqq->next_rq == next) |
1586 | cfqq->next_rq = rq; | |
b4878f24 | 1587 | cfq_remove_request(next); |
e98ef89b VG |
1588 | cfq_blkiocg_update_io_merged_stats(&(RQ_CFQG(rq))->blkg, |
1589 | rq_data_dir(next), rq_is_sync(next)); | |
22e2c507 JA |
1590 | } |
1591 | ||
165125e1 | 1592 | static int cfq_allow_merge(struct request_queue *q, struct request *rq, |
da775265 JA |
1593 | struct bio *bio) |
1594 | { | |
1595 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
91fac317 | 1596 | struct cfq_io_context *cic; |
da775265 | 1597 | struct cfq_queue *cfqq; |
da775265 JA |
1598 | |
1599 | /* | |
ec8acb69 | 1600 | * Disallow merge of a sync bio into an async request. |
da775265 | 1601 | */ |
91fac317 | 1602 | if (cfq_bio_sync(bio) && !rq_is_sync(rq)) |
a6151c3a | 1603 | return false; |
da775265 JA |
1604 | |
1605 | /* | |
719d3402 JA |
1606 | * Lookup the cfqq that this bio will be queued with. Allow |
1607 | * merge only if rq is queued there. | |
da775265 | 1608 | */ |
4ac845a2 | 1609 | cic = cfq_cic_lookup(cfqd, current->io_context); |
91fac317 | 1610 | if (!cic) |
a6151c3a | 1611 | return false; |
719d3402 | 1612 | |
91fac317 | 1613 | cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); |
a6151c3a | 1614 | return cfqq == RQ_CFQQ(rq); |
da775265 JA |
1615 | } |
1616 | ||
812df48d DS |
1617 | static inline void cfq_del_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1618 | { | |
1619 | del_timer(&cfqd->idle_slice_timer); | |
e98ef89b | 1620 | cfq_blkiocg_update_idle_time_stats(&cfqq->cfqg->blkg); |
812df48d DS |
1621 | } |
1622 | ||
febffd61 JA |
1623 | static void __cfq_set_active_queue(struct cfq_data *cfqd, |
1624 | struct cfq_queue *cfqq) | |
22e2c507 JA |
1625 | { |
1626 | if (cfqq) { | |
b1ffe737 DS |
1627 | cfq_log_cfqq(cfqd, cfqq, "set_active wl_prio:%d wl_type:%d", |
1628 | cfqd->serving_prio, cfqd->serving_type); | |
62a37f6b JT |
1629 | cfq_blkiocg_update_avg_queue_size_stats(&cfqq->cfqg->blkg); |
1630 | cfqq->slice_start = 0; | |
1631 | cfqq->dispatch_start = jiffies; | |
1632 | cfqq->allocated_slice = 0; | |
1633 | cfqq->slice_end = 0; | |
1634 | cfqq->slice_dispatch = 0; | |
1635 | cfqq->nr_sectors = 0; | |
1636 | ||
1637 | cfq_clear_cfqq_wait_request(cfqq); | |
1638 | cfq_clear_cfqq_must_dispatch(cfqq); | |
1639 | cfq_clear_cfqq_must_alloc_slice(cfqq); | |
1640 | cfq_clear_cfqq_fifo_expire(cfqq); | |
1641 | cfq_mark_cfqq_slice_new(cfqq); | |
1642 | ||
1643 | cfq_del_timer(cfqd, cfqq); | |
22e2c507 JA |
1644 | } |
1645 | ||
1646 | cfqd->active_queue = cfqq; | |
1647 | } | |
1648 | ||
7b14e3b5 JA |
1649 | /* |
1650 | * current cfqq expired its slice (or was too idle), select new one | |
1651 | */ | |
1652 | static void | |
1653 | __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
e5ff082e | 1654 | bool timed_out) |
7b14e3b5 | 1655 | { |
7b679138 JA |
1656 | cfq_log_cfqq(cfqd, cfqq, "slice expired t=%d", timed_out); |
1657 | ||
7b14e3b5 | 1658 | if (cfq_cfqq_wait_request(cfqq)) |
812df48d | 1659 | cfq_del_timer(cfqd, cfqq); |
7b14e3b5 | 1660 | |
7b14e3b5 | 1661 | cfq_clear_cfqq_wait_request(cfqq); |
f75edf2d | 1662 | cfq_clear_cfqq_wait_busy(cfqq); |
7b14e3b5 | 1663 | |
ae54abed SL |
1664 | /* |
1665 | * If this cfqq is shared between multiple processes, check to | |
1666 | * make sure that those processes are still issuing I/Os within | |
1667 | * the mean seek distance. If not, it may be time to break the | |
1668 | * queues apart again. | |
1669 | */ | |
1670 | if (cfq_cfqq_coop(cfqq) && CFQQ_SEEKY(cfqq)) | |
1671 | cfq_mark_cfqq_split_coop(cfqq); | |
1672 | ||
7b14e3b5 | 1673 | /* |
6084cdda | 1674 | * store what was left of this slice, if the queue idled/timed out |
7b14e3b5 | 1675 | */ |
c553f8e3 SL |
1676 | if (timed_out) { |
1677 | if (cfq_cfqq_slice_new(cfqq)) | |
ba5bd520 | 1678 | cfqq->slice_resid = cfq_scaled_cfqq_slice(cfqd, cfqq); |
c553f8e3 SL |
1679 | else |
1680 | cfqq->slice_resid = cfqq->slice_end - jiffies; | |
7b679138 JA |
1681 | cfq_log_cfqq(cfqd, cfqq, "resid=%ld", cfqq->slice_resid); |
1682 | } | |
7b14e3b5 | 1683 | |
e5ff082e | 1684 | cfq_group_served(cfqd, cfqq->cfqg, cfqq); |
dae739eb | 1685 | |
f04a6424 VG |
1686 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) |
1687 | cfq_del_cfqq_rr(cfqd, cfqq); | |
1688 | ||
edd75ffd | 1689 | cfq_resort_rr_list(cfqd, cfqq); |
7b14e3b5 JA |
1690 | |
1691 | if (cfqq == cfqd->active_queue) | |
1692 | cfqd->active_queue = NULL; | |
1693 | ||
1694 | if (cfqd->active_cic) { | |
1695 | put_io_context(cfqd->active_cic->ioc); | |
1696 | cfqd->active_cic = NULL; | |
1697 | } | |
7b14e3b5 JA |
1698 | } |
1699 | ||
e5ff082e | 1700 | static inline void cfq_slice_expired(struct cfq_data *cfqd, bool timed_out) |
7b14e3b5 JA |
1701 | { |
1702 | struct cfq_queue *cfqq = cfqd->active_queue; | |
1703 | ||
1704 | if (cfqq) | |
e5ff082e | 1705 | __cfq_slice_expired(cfqd, cfqq, timed_out); |
7b14e3b5 JA |
1706 | } |
1707 | ||
498d3aa2 JA |
1708 | /* |
1709 | * Get next queue for service. Unless we have a queue preemption, | |
1710 | * we'll simply select the first cfqq in the service tree. | |
1711 | */ | |
6d048f53 | 1712 | static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd) |
22e2c507 | 1713 | { |
c0324a02 | 1714 | struct cfq_rb_root *service_tree = |
cdb16e8f | 1715 | service_tree_for(cfqd->serving_group, cfqd->serving_prio, |
65b32a57 | 1716 | cfqd->serving_type); |
d9e7620e | 1717 | |
f04a6424 VG |
1718 | if (!cfqd->rq_queued) |
1719 | return NULL; | |
1720 | ||
1fa8f6d6 VG |
1721 | /* There is nothing to dispatch */ |
1722 | if (!service_tree) | |
1723 | return NULL; | |
c0324a02 CZ |
1724 | if (RB_EMPTY_ROOT(&service_tree->rb)) |
1725 | return NULL; | |
1726 | return cfq_rb_first(service_tree); | |
6d048f53 JA |
1727 | } |
1728 | ||
f04a6424 VG |
1729 | static struct cfq_queue *cfq_get_next_queue_forced(struct cfq_data *cfqd) |
1730 | { | |
25fb5169 | 1731 | struct cfq_group *cfqg; |
f04a6424 VG |
1732 | struct cfq_queue *cfqq; |
1733 | int i, j; | |
1734 | struct cfq_rb_root *st; | |
1735 | ||
1736 | if (!cfqd->rq_queued) | |
1737 | return NULL; | |
1738 | ||
25fb5169 VG |
1739 | cfqg = cfq_get_next_cfqg(cfqd); |
1740 | if (!cfqg) | |
1741 | return NULL; | |
1742 | ||
f04a6424 VG |
1743 | for_each_cfqg_st(cfqg, i, j, st) |
1744 | if ((cfqq = cfq_rb_first(st)) != NULL) | |
1745 | return cfqq; | |
1746 | return NULL; | |
1747 | } | |
1748 | ||
498d3aa2 JA |
1749 | /* |
1750 | * Get and set a new active queue for service. | |
1751 | */ | |
a36e71f9 JA |
1752 | static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd, |
1753 | struct cfq_queue *cfqq) | |
6d048f53 | 1754 | { |
e00ef799 | 1755 | if (!cfqq) |
a36e71f9 | 1756 | cfqq = cfq_get_next_queue(cfqd); |
6d048f53 | 1757 | |
22e2c507 | 1758 | __cfq_set_active_queue(cfqd, cfqq); |
3b18152c | 1759 | return cfqq; |
22e2c507 JA |
1760 | } |
1761 | ||
d9e7620e JA |
1762 | static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd, |
1763 | struct request *rq) | |
1764 | { | |
83096ebf TH |
1765 | if (blk_rq_pos(rq) >= cfqd->last_position) |
1766 | return blk_rq_pos(rq) - cfqd->last_position; | |
d9e7620e | 1767 | else |
83096ebf | 1768 | return cfqd->last_position - blk_rq_pos(rq); |
d9e7620e JA |
1769 | } |
1770 | ||
b2c18e1e | 1771 | static inline int cfq_rq_close(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
e9ce335d | 1772 | struct request *rq) |
6d048f53 | 1773 | { |
e9ce335d | 1774 | return cfq_dist_from_last(cfqd, rq) <= CFQQ_CLOSE_THR; |
6d048f53 JA |
1775 | } |
1776 | ||
a36e71f9 JA |
1777 | static struct cfq_queue *cfqq_close(struct cfq_data *cfqd, |
1778 | struct cfq_queue *cur_cfqq) | |
1779 | { | |
f2d1f0ae | 1780 | struct rb_root *root = &cfqd->prio_trees[cur_cfqq->org_ioprio]; |
a36e71f9 JA |
1781 | struct rb_node *parent, *node; |
1782 | struct cfq_queue *__cfqq; | |
1783 | sector_t sector = cfqd->last_position; | |
1784 | ||
1785 | if (RB_EMPTY_ROOT(root)) | |
1786 | return NULL; | |
1787 | ||
1788 | /* | |
1789 | * First, if we find a request starting at the end of the last | |
1790 | * request, choose it. | |
1791 | */ | |
f2d1f0ae | 1792 | __cfqq = cfq_prio_tree_lookup(cfqd, root, sector, &parent, NULL); |
a36e71f9 JA |
1793 | if (__cfqq) |
1794 | return __cfqq; | |
1795 | ||
1796 | /* | |
1797 | * If the exact sector wasn't found, the parent of the NULL leaf | |
1798 | * will contain the closest sector. | |
1799 | */ | |
1800 | __cfqq = rb_entry(parent, struct cfq_queue, p_node); | |
e9ce335d | 1801 | if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq)) |
a36e71f9 JA |
1802 | return __cfqq; |
1803 | ||
2e46e8b2 | 1804 | if (blk_rq_pos(__cfqq->next_rq) < sector) |
a36e71f9 JA |
1805 | node = rb_next(&__cfqq->p_node); |
1806 | else | |
1807 | node = rb_prev(&__cfqq->p_node); | |
1808 | if (!node) | |
1809 | return NULL; | |
1810 | ||
1811 | __cfqq = rb_entry(node, struct cfq_queue, p_node); | |
e9ce335d | 1812 | if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq)) |
a36e71f9 JA |
1813 | return __cfqq; |
1814 | ||
1815 | return NULL; | |
1816 | } | |
1817 | ||
1818 | /* | |
1819 | * cfqd - obvious | |
1820 | * cur_cfqq - passed in so that we don't decide that the current queue is | |
1821 | * closely cooperating with itself. | |
1822 | * | |
1823 | * So, basically we're assuming that that cur_cfqq has dispatched at least | |
1824 | * one request, and that cfqd->last_position reflects a position on the disk | |
1825 | * associated with the I/O issued by cur_cfqq. I'm not sure this is a valid | |
1826 | * assumption. | |
1827 | */ | |
1828 | static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd, | |
b3b6d040 | 1829 | struct cfq_queue *cur_cfqq) |
6d048f53 | 1830 | { |
a36e71f9 JA |
1831 | struct cfq_queue *cfqq; |
1832 | ||
39c01b21 DS |
1833 | if (cfq_class_idle(cur_cfqq)) |
1834 | return NULL; | |
e6c5bc73 JM |
1835 | if (!cfq_cfqq_sync(cur_cfqq)) |
1836 | return NULL; | |
1837 | if (CFQQ_SEEKY(cur_cfqq)) | |
1838 | return NULL; | |
1839 | ||
b9d8f4c7 GJ |
1840 | /* |
1841 | * Don't search priority tree if it's the only queue in the group. | |
1842 | */ | |
1843 | if (cur_cfqq->cfqg->nr_cfqq == 1) | |
1844 | return NULL; | |
1845 | ||
6d048f53 | 1846 | /* |
d9e7620e JA |
1847 | * We should notice if some of the queues are cooperating, eg |
1848 | * working closely on the same area of the disk. In that case, | |
1849 | * we can group them together and don't waste time idling. | |
6d048f53 | 1850 | */ |
a36e71f9 JA |
1851 | cfqq = cfqq_close(cfqd, cur_cfqq); |
1852 | if (!cfqq) | |
1853 | return NULL; | |
1854 | ||
8682e1f1 VG |
1855 | /* If new queue belongs to different cfq_group, don't choose it */ |
1856 | if (cur_cfqq->cfqg != cfqq->cfqg) | |
1857 | return NULL; | |
1858 | ||
df5fe3e8 JM |
1859 | /* |
1860 | * It only makes sense to merge sync queues. | |
1861 | */ | |
1862 | if (!cfq_cfqq_sync(cfqq)) | |
1863 | return NULL; | |
e6c5bc73 JM |
1864 | if (CFQQ_SEEKY(cfqq)) |
1865 | return NULL; | |
df5fe3e8 | 1866 | |
c0324a02 CZ |
1867 | /* |
1868 | * Do not merge queues of different priority classes | |
1869 | */ | |
1870 | if (cfq_class_rt(cfqq) != cfq_class_rt(cur_cfqq)) | |
1871 | return NULL; | |
1872 | ||
a36e71f9 | 1873 | return cfqq; |
6d048f53 JA |
1874 | } |
1875 | ||
a6d44e98 CZ |
1876 | /* |
1877 | * Determine whether we should enforce idle window for this queue. | |
1878 | */ | |
1879 | ||
1880 | static bool cfq_should_idle(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1881 | { | |
1882 | enum wl_prio_t prio = cfqq_prio(cfqq); | |
718eee05 | 1883 | struct cfq_rb_root *service_tree = cfqq->service_tree; |
a6d44e98 | 1884 | |
f04a6424 VG |
1885 | BUG_ON(!service_tree); |
1886 | BUG_ON(!service_tree->count); | |
1887 | ||
b6508c16 VG |
1888 | if (!cfqd->cfq_slice_idle) |
1889 | return false; | |
1890 | ||
a6d44e98 CZ |
1891 | /* We never do for idle class queues. */ |
1892 | if (prio == IDLE_WORKLOAD) | |
1893 | return false; | |
1894 | ||
1895 | /* We do for queues that were marked with idle window flag. */ | |
3c764b7a SL |
1896 | if (cfq_cfqq_idle_window(cfqq) && |
1897 | !(blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag)) | |
a6d44e98 CZ |
1898 | return true; |
1899 | ||
1900 | /* | |
1901 | * Otherwise, we do only if they are the last ones | |
1902 | * in their service tree. | |
1903 | */ | |
b1ffe737 | 1904 | if (service_tree->count == 1 && cfq_cfqq_sync(cfqq)) |
c1e44756 | 1905 | return true; |
b1ffe737 DS |
1906 | cfq_log_cfqq(cfqd, cfqq, "Not idling. st->count:%d", |
1907 | service_tree->count); | |
c1e44756 | 1908 | return false; |
a6d44e98 CZ |
1909 | } |
1910 | ||
6d048f53 | 1911 | static void cfq_arm_slice_timer(struct cfq_data *cfqd) |
22e2c507 | 1912 | { |
1792669c | 1913 | struct cfq_queue *cfqq = cfqd->active_queue; |
206dc69b | 1914 | struct cfq_io_context *cic; |
80bdf0c7 | 1915 | unsigned long sl, group_idle = 0; |
7b14e3b5 | 1916 | |
a68bbddb | 1917 | /* |
f7d7b7a7 JA |
1918 | * SSD device without seek penalty, disable idling. But only do so |
1919 | * for devices that support queuing, otherwise we still have a problem | |
1920 | * with sync vs async workloads. | |
a68bbddb | 1921 | */ |
f7d7b7a7 | 1922 | if (blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag) |
a68bbddb JA |
1923 | return; |
1924 | ||
dd67d051 | 1925 | WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list)); |
6d048f53 | 1926 | WARN_ON(cfq_cfqq_slice_new(cfqq)); |
22e2c507 JA |
1927 | |
1928 | /* | |
1929 | * idle is disabled, either manually or by past process history | |
1930 | */ | |
80bdf0c7 VG |
1931 | if (!cfq_should_idle(cfqd, cfqq)) { |
1932 | /* no queue idling. Check for group idling */ | |
1933 | if (cfqd->cfq_group_idle) | |
1934 | group_idle = cfqd->cfq_group_idle; | |
1935 | else | |
1936 | return; | |
1937 | } | |
6d048f53 | 1938 | |
7b679138 | 1939 | /* |
8e550632 | 1940 | * still active requests from this queue, don't idle |
7b679138 | 1941 | */ |
8e550632 | 1942 | if (cfqq->dispatched) |
7b679138 JA |
1943 | return; |
1944 | ||
22e2c507 JA |
1945 | /* |
1946 | * task has exited, don't wait | |
1947 | */ | |
206dc69b | 1948 | cic = cfqd->active_cic; |
66dac98e | 1949 | if (!cic || !atomic_read(&cic->ioc->nr_tasks)) |
6d048f53 JA |
1950 | return; |
1951 | ||
355b659c CZ |
1952 | /* |
1953 | * If our average think time is larger than the remaining time | |
1954 | * slice, then don't idle. This avoids overrunning the allotted | |
1955 | * time slice. | |
1956 | */ | |
1957 | if (sample_valid(cic->ttime_samples) && | |
b1ffe737 DS |
1958 | (cfqq->slice_end - jiffies < cic->ttime_mean)) { |
1959 | cfq_log_cfqq(cfqd, cfqq, "Not idling. think_time:%d", | |
1960 | cic->ttime_mean); | |
355b659c | 1961 | return; |
b1ffe737 | 1962 | } |
355b659c | 1963 | |
80bdf0c7 VG |
1964 | /* There are other queues in the group, don't do group idle */ |
1965 | if (group_idle && cfqq->cfqg->nr_cfqq > 1) | |
1966 | return; | |
1967 | ||
3b18152c | 1968 | cfq_mark_cfqq_wait_request(cfqq); |
22e2c507 | 1969 | |
80bdf0c7 VG |
1970 | if (group_idle) |
1971 | sl = cfqd->cfq_group_idle; | |
1972 | else | |
1973 | sl = cfqd->cfq_slice_idle; | |
206dc69b | 1974 | |
7b14e3b5 | 1975 | mod_timer(&cfqd->idle_slice_timer, jiffies + sl); |
e98ef89b | 1976 | cfq_blkiocg_update_set_idle_time_stats(&cfqq->cfqg->blkg); |
80bdf0c7 VG |
1977 | cfq_log_cfqq(cfqd, cfqq, "arm_idle: %lu group_idle: %d", sl, |
1978 | group_idle ? 1 : 0); | |
1da177e4 LT |
1979 | } |
1980 | ||
498d3aa2 JA |
1981 | /* |
1982 | * Move request from internal lists to the request queue dispatch list. | |
1983 | */ | |
165125e1 | 1984 | static void cfq_dispatch_insert(struct request_queue *q, struct request *rq) |
1da177e4 | 1985 | { |
3ed9a296 | 1986 | struct cfq_data *cfqd = q->elevator->elevator_data; |
5e705374 | 1987 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 | 1988 | |
7b679138 JA |
1989 | cfq_log_cfqq(cfqd, cfqq, "dispatch_insert"); |
1990 | ||
06d21886 | 1991 | cfqq->next_rq = cfq_find_next_rq(cfqd, cfqq, rq); |
5380a101 | 1992 | cfq_remove_request(rq); |
6d048f53 | 1993 | cfqq->dispatched++; |
80bdf0c7 | 1994 | (RQ_CFQG(rq))->dispatched++; |
5380a101 | 1995 | elv_dispatch_sort(q, rq); |
3ed9a296 | 1996 | |
53c583d2 | 1997 | cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]++; |
c4e7893e | 1998 | cfqq->nr_sectors += blk_rq_sectors(rq); |
e98ef89b | 1999 | cfq_blkiocg_update_dispatch_stats(&cfqq->cfqg->blkg, blk_rq_bytes(rq), |
84c124da | 2000 | rq_data_dir(rq), rq_is_sync(rq)); |
1da177e4 LT |
2001 | } |
2002 | ||
2003 | /* | |
2004 | * return expired entry, or NULL to just start from scratch in rbtree | |
2005 | */ | |
febffd61 | 2006 | static struct request *cfq_check_fifo(struct cfq_queue *cfqq) |
1da177e4 | 2007 | { |
30996f40 | 2008 | struct request *rq = NULL; |
1da177e4 | 2009 | |
3b18152c | 2010 | if (cfq_cfqq_fifo_expire(cfqq)) |
1da177e4 | 2011 | return NULL; |
cb887411 JA |
2012 | |
2013 | cfq_mark_cfqq_fifo_expire(cfqq); | |
2014 | ||
89850f7e JA |
2015 | if (list_empty(&cfqq->fifo)) |
2016 | return NULL; | |
1da177e4 | 2017 | |
89850f7e | 2018 | rq = rq_entry_fifo(cfqq->fifo.next); |
30996f40 | 2019 | if (time_before(jiffies, rq_fifo_time(rq))) |
7b679138 | 2020 | rq = NULL; |
1da177e4 | 2021 | |
30996f40 | 2022 | cfq_log_cfqq(cfqq->cfqd, cfqq, "fifo=%p", rq); |
6d048f53 | 2023 | return rq; |
1da177e4 LT |
2024 | } |
2025 | ||
22e2c507 JA |
2026 | static inline int |
2027 | cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
2028 | { | |
2029 | const int base_rq = cfqd->cfq_slice_async_rq; | |
1da177e4 | 2030 | |
22e2c507 | 2031 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); |
1da177e4 | 2032 | |
22e2c507 | 2033 | return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio)); |
1da177e4 LT |
2034 | } |
2035 | ||
df5fe3e8 JM |
2036 | /* |
2037 | * Must be called with the queue_lock held. | |
2038 | */ | |
2039 | static int cfqq_process_refs(struct cfq_queue *cfqq) | |
2040 | { | |
2041 | int process_refs, io_refs; | |
2042 | ||
2043 | io_refs = cfqq->allocated[READ] + cfqq->allocated[WRITE]; | |
30d7b944 | 2044 | process_refs = cfqq->ref - io_refs; |
df5fe3e8 JM |
2045 | BUG_ON(process_refs < 0); |
2046 | return process_refs; | |
2047 | } | |
2048 | ||
2049 | static void cfq_setup_merge(struct cfq_queue *cfqq, struct cfq_queue *new_cfqq) | |
2050 | { | |
e6c5bc73 | 2051 | int process_refs, new_process_refs; |
df5fe3e8 JM |
2052 | struct cfq_queue *__cfqq; |
2053 | ||
c10b61f0 JM |
2054 | /* |
2055 | * If there are no process references on the new_cfqq, then it is | |
2056 | * unsafe to follow the ->new_cfqq chain as other cfqq's in the | |
2057 | * chain may have dropped their last reference (not just their | |
2058 | * last process reference). | |
2059 | */ | |
2060 | if (!cfqq_process_refs(new_cfqq)) | |
2061 | return; | |
2062 | ||
df5fe3e8 JM |
2063 | /* Avoid a circular list and skip interim queue merges */ |
2064 | while ((__cfqq = new_cfqq->new_cfqq)) { | |
2065 | if (__cfqq == cfqq) | |
2066 | return; | |
2067 | new_cfqq = __cfqq; | |
2068 | } | |
2069 | ||
2070 | process_refs = cfqq_process_refs(cfqq); | |
c10b61f0 | 2071 | new_process_refs = cfqq_process_refs(new_cfqq); |
df5fe3e8 JM |
2072 | /* |
2073 | * If the process for the cfqq has gone away, there is no | |
2074 | * sense in merging the queues. | |
2075 | */ | |
c10b61f0 | 2076 | if (process_refs == 0 || new_process_refs == 0) |
df5fe3e8 JM |
2077 | return; |
2078 | ||
e6c5bc73 JM |
2079 | /* |
2080 | * Merge in the direction of the lesser amount of work. | |
2081 | */ | |
e6c5bc73 JM |
2082 | if (new_process_refs >= process_refs) { |
2083 | cfqq->new_cfqq = new_cfqq; | |
30d7b944 | 2084 | new_cfqq->ref += process_refs; |
e6c5bc73 JM |
2085 | } else { |
2086 | new_cfqq->new_cfqq = cfqq; | |
30d7b944 | 2087 | cfqq->ref += new_process_refs; |
e6c5bc73 | 2088 | } |
df5fe3e8 JM |
2089 | } |
2090 | ||
cdb16e8f | 2091 | static enum wl_type_t cfq_choose_wl(struct cfq_data *cfqd, |
65b32a57 | 2092 | struct cfq_group *cfqg, enum wl_prio_t prio) |
718eee05 CZ |
2093 | { |
2094 | struct cfq_queue *queue; | |
2095 | int i; | |
2096 | bool key_valid = false; | |
2097 | unsigned long lowest_key = 0; | |
2098 | enum wl_type_t cur_best = SYNC_NOIDLE_WORKLOAD; | |
2099 | ||
65b32a57 VG |
2100 | for (i = 0; i <= SYNC_WORKLOAD; ++i) { |
2101 | /* select the one with lowest rb_key */ | |
2102 | queue = cfq_rb_first(service_tree_for(cfqg, prio, i)); | |
718eee05 CZ |
2103 | if (queue && |
2104 | (!key_valid || time_before(queue->rb_key, lowest_key))) { | |
2105 | lowest_key = queue->rb_key; | |
2106 | cur_best = i; | |
2107 | key_valid = true; | |
2108 | } | |
2109 | } | |
2110 | ||
2111 | return cur_best; | |
2112 | } | |
2113 | ||
cdb16e8f | 2114 | static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg) |
718eee05 | 2115 | { |
718eee05 CZ |
2116 | unsigned slice; |
2117 | unsigned count; | |
cdb16e8f | 2118 | struct cfq_rb_root *st; |
58ff82f3 | 2119 | unsigned group_slice; |
e4ea0c16 | 2120 | enum wl_prio_t original_prio = cfqd->serving_prio; |
1fa8f6d6 | 2121 | |
718eee05 | 2122 | /* Choose next priority. RT > BE > IDLE */ |
58ff82f3 | 2123 | if (cfq_group_busy_queues_wl(RT_WORKLOAD, cfqd, cfqg)) |
718eee05 | 2124 | cfqd->serving_prio = RT_WORKLOAD; |
58ff82f3 | 2125 | else if (cfq_group_busy_queues_wl(BE_WORKLOAD, cfqd, cfqg)) |
718eee05 CZ |
2126 | cfqd->serving_prio = BE_WORKLOAD; |
2127 | else { | |
2128 | cfqd->serving_prio = IDLE_WORKLOAD; | |
2129 | cfqd->workload_expires = jiffies + 1; | |
2130 | return; | |
2131 | } | |
2132 | ||
e4ea0c16 SL |
2133 | if (original_prio != cfqd->serving_prio) |
2134 | goto new_workload; | |
2135 | ||
718eee05 CZ |
2136 | /* |
2137 | * For RT and BE, we have to choose also the type | |
2138 | * (SYNC, SYNC_NOIDLE, ASYNC), and to compute a workload | |
2139 | * expiration time | |
2140 | */ | |
65b32a57 | 2141 | st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type); |
cdb16e8f | 2142 | count = st->count; |
718eee05 CZ |
2143 | |
2144 | /* | |
65b32a57 | 2145 | * check workload expiration, and that we still have other queues ready |
718eee05 | 2146 | */ |
65b32a57 | 2147 | if (count && !time_after(jiffies, cfqd->workload_expires)) |
718eee05 CZ |
2148 | return; |
2149 | ||
e4ea0c16 | 2150 | new_workload: |
718eee05 CZ |
2151 | /* otherwise select new workload type */ |
2152 | cfqd->serving_type = | |
65b32a57 VG |
2153 | cfq_choose_wl(cfqd, cfqg, cfqd->serving_prio); |
2154 | st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type); | |
cdb16e8f | 2155 | count = st->count; |
718eee05 CZ |
2156 | |
2157 | /* | |
2158 | * the workload slice is computed as a fraction of target latency | |
2159 | * proportional to the number of queues in that workload, over | |
2160 | * all the queues in the same priority class | |
2161 | */ | |
58ff82f3 VG |
2162 | group_slice = cfq_group_slice(cfqd, cfqg); |
2163 | ||
2164 | slice = group_slice * count / | |
2165 | max_t(unsigned, cfqg->busy_queues_avg[cfqd->serving_prio], | |
2166 | cfq_group_busy_queues_wl(cfqd->serving_prio, cfqd, cfqg)); | |
718eee05 | 2167 | |
f26bd1f0 VG |
2168 | if (cfqd->serving_type == ASYNC_WORKLOAD) { |
2169 | unsigned int tmp; | |
2170 | ||
2171 | /* | |
2172 | * Async queues are currently system wide. Just taking | |
2173 | * proportion of queues with-in same group will lead to higher | |
2174 | * async ratio system wide as generally root group is going | |
2175 | * to have higher weight. A more accurate thing would be to | |
2176 | * calculate system wide asnc/sync ratio. | |
2177 | */ | |
2178 | tmp = cfq_target_latency * cfqg_busy_async_queues(cfqd, cfqg); | |
2179 | tmp = tmp/cfqd->busy_queues; | |
2180 | slice = min_t(unsigned, slice, tmp); | |
2181 | ||
718eee05 CZ |
2182 | /* async workload slice is scaled down according to |
2183 | * the sync/async slice ratio. */ | |
2184 | slice = slice * cfqd->cfq_slice[0] / cfqd->cfq_slice[1]; | |
f26bd1f0 | 2185 | } else |
718eee05 CZ |
2186 | /* sync workload slice is at least 2 * cfq_slice_idle */ |
2187 | slice = max(slice, 2 * cfqd->cfq_slice_idle); | |
2188 | ||
2189 | slice = max_t(unsigned, slice, CFQ_MIN_TT); | |
b1ffe737 | 2190 | cfq_log(cfqd, "workload slice:%d", slice); |
718eee05 CZ |
2191 | cfqd->workload_expires = jiffies + slice; |
2192 | } | |
2193 | ||
1fa8f6d6 VG |
2194 | static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd) |
2195 | { | |
2196 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
25bc6b07 | 2197 | struct cfq_group *cfqg; |
1fa8f6d6 VG |
2198 | |
2199 | if (RB_EMPTY_ROOT(&st->rb)) | |
2200 | return NULL; | |
25bc6b07 | 2201 | cfqg = cfq_rb_first_group(st); |
25bc6b07 VG |
2202 | update_min_vdisktime(st); |
2203 | return cfqg; | |
1fa8f6d6 VG |
2204 | } |
2205 | ||
cdb16e8f VG |
2206 | static void cfq_choose_cfqg(struct cfq_data *cfqd) |
2207 | { | |
1fa8f6d6 VG |
2208 | struct cfq_group *cfqg = cfq_get_next_cfqg(cfqd); |
2209 | ||
2210 | cfqd->serving_group = cfqg; | |
dae739eb VG |
2211 | |
2212 | /* Restore the workload type data */ | |
2213 | if (cfqg->saved_workload_slice) { | |
2214 | cfqd->workload_expires = jiffies + cfqg->saved_workload_slice; | |
2215 | cfqd->serving_type = cfqg->saved_workload; | |
2216 | cfqd->serving_prio = cfqg->saved_serving_prio; | |
66ae2919 GJ |
2217 | } else |
2218 | cfqd->workload_expires = jiffies - 1; | |
2219 | ||
1fa8f6d6 | 2220 | choose_service_tree(cfqd, cfqg); |
cdb16e8f VG |
2221 | } |
2222 | ||
22e2c507 | 2223 | /* |
498d3aa2 JA |
2224 | * Select a queue for service. If we have a current active queue, |
2225 | * check whether to continue servicing it, or retrieve and set a new one. | |
22e2c507 | 2226 | */ |
1b5ed5e1 | 2227 | static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) |
1da177e4 | 2228 | { |
a36e71f9 | 2229 | struct cfq_queue *cfqq, *new_cfqq = NULL; |
1da177e4 | 2230 | |
22e2c507 JA |
2231 | cfqq = cfqd->active_queue; |
2232 | if (!cfqq) | |
2233 | goto new_queue; | |
1da177e4 | 2234 | |
f04a6424 VG |
2235 | if (!cfqd->rq_queued) |
2236 | return NULL; | |
c244bb50 VG |
2237 | |
2238 | /* | |
2239 | * We were waiting for group to get backlogged. Expire the queue | |
2240 | */ | |
2241 | if (cfq_cfqq_wait_busy(cfqq) && !RB_EMPTY_ROOT(&cfqq->sort_list)) | |
2242 | goto expire; | |
2243 | ||
22e2c507 | 2244 | /* |
6d048f53 | 2245 | * The active queue has run out of time, expire it and select new. |
22e2c507 | 2246 | */ |
7667aa06 VG |
2247 | if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq)) { |
2248 | /* | |
2249 | * If slice had not expired at the completion of last request | |
2250 | * we might not have turned on wait_busy flag. Don't expire | |
2251 | * the queue yet. Allow the group to get backlogged. | |
2252 | * | |
2253 | * The very fact that we have used the slice, that means we | |
2254 | * have been idling all along on this queue and it should be | |
2255 | * ok to wait for this request to complete. | |
2256 | */ | |
82bbbf28 VG |
2257 | if (cfqq->cfqg->nr_cfqq == 1 && RB_EMPTY_ROOT(&cfqq->sort_list) |
2258 | && cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) { | |
2259 | cfqq = NULL; | |
7667aa06 | 2260 | goto keep_queue; |
82bbbf28 | 2261 | } else |
80bdf0c7 | 2262 | goto check_group_idle; |
7667aa06 | 2263 | } |
1da177e4 | 2264 | |
22e2c507 | 2265 | /* |
6d048f53 JA |
2266 | * The active queue has requests and isn't expired, allow it to |
2267 | * dispatch. | |
22e2c507 | 2268 | */ |
dd67d051 | 2269 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
22e2c507 | 2270 | goto keep_queue; |
6d048f53 | 2271 | |
a36e71f9 JA |
2272 | /* |
2273 | * If another queue has a request waiting within our mean seek | |
2274 | * distance, let it run. The expire code will check for close | |
2275 | * cooperators and put the close queue at the front of the service | |
df5fe3e8 | 2276 | * tree. If possible, merge the expiring queue with the new cfqq. |
a36e71f9 | 2277 | */ |
b3b6d040 | 2278 | new_cfqq = cfq_close_cooperator(cfqd, cfqq); |
df5fe3e8 JM |
2279 | if (new_cfqq) { |
2280 | if (!cfqq->new_cfqq) | |
2281 | cfq_setup_merge(cfqq, new_cfqq); | |
a36e71f9 | 2282 | goto expire; |
df5fe3e8 | 2283 | } |
a36e71f9 | 2284 | |
6d048f53 JA |
2285 | /* |
2286 | * No requests pending. If the active queue still has requests in | |
2287 | * flight or is idling for a new request, allow either of these | |
2288 | * conditions to happen (or time out) before selecting a new queue. | |
2289 | */ | |
80bdf0c7 VG |
2290 | if (timer_pending(&cfqd->idle_slice_timer)) { |
2291 | cfqq = NULL; | |
2292 | goto keep_queue; | |
2293 | } | |
2294 | ||
8e1ac665 SL |
2295 | /* |
2296 | * This is a deep seek queue, but the device is much faster than | |
2297 | * the queue can deliver, don't idle | |
2298 | **/ | |
2299 | if (CFQQ_SEEKY(cfqq) && cfq_cfqq_idle_window(cfqq) && | |
2300 | (cfq_cfqq_slice_new(cfqq) || | |
2301 | (cfqq->slice_end - jiffies > jiffies - cfqq->slice_start))) { | |
2302 | cfq_clear_cfqq_deep(cfqq); | |
2303 | cfq_clear_cfqq_idle_window(cfqq); | |
2304 | } | |
2305 | ||
80bdf0c7 VG |
2306 | if (cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) { |
2307 | cfqq = NULL; | |
2308 | goto keep_queue; | |
2309 | } | |
2310 | ||
2311 | /* | |
2312 | * If group idle is enabled and there are requests dispatched from | |
2313 | * this group, wait for requests to complete. | |
2314 | */ | |
2315 | check_group_idle: | |
2316 | if (cfqd->cfq_group_idle && cfqq->cfqg->nr_cfqq == 1 | |
2317 | && cfqq->cfqg->dispatched) { | |
caaa5f9f JA |
2318 | cfqq = NULL; |
2319 | goto keep_queue; | |
22e2c507 JA |
2320 | } |
2321 | ||
3b18152c | 2322 | expire: |
e5ff082e | 2323 | cfq_slice_expired(cfqd, 0); |
3b18152c | 2324 | new_queue: |
718eee05 CZ |
2325 | /* |
2326 | * Current queue expired. Check if we have to switch to a new | |
2327 | * service tree | |
2328 | */ | |
2329 | if (!new_cfqq) | |
cdb16e8f | 2330 | cfq_choose_cfqg(cfqd); |
718eee05 | 2331 | |
a36e71f9 | 2332 | cfqq = cfq_set_active_queue(cfqd, new_cfqq); |
22e2c507 | 2333 | keep_queue: |
3b18152c | 2334 | return cfqq; |
22e2c507 JA |
2335 | } |
2336 | ||
febffd61 | 2337 | static int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq) |
d9e7620e JA |
2338 | { |
2339 | int dispatched = 0; | |
2340 | ||
2341 | while (cfqq->next_rq) { | |
2342 | cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq); | |
2343 | dispatched++; | |
2344 | } | |
2345 | ||
2346 | BUG_ON(!list_empty(&cfqq->fifo)); | |
f04a6424 VG |
2347 | |
2348 | /* By default cfqq is not expired if it is empty. Do it explicitly */ | |
e5ff082e | 2349 | __cfq_slice_expired(cfqq->cfqd, cfqq, 0); |
d9e7620e JA |
2350 | return dispatched; |
2351 | } | |
2352 | ||
498d3aa2 JA |
2353 | /* |
2354 | * Drain our current requests. Used for barriers and when switching | |
2355 | * io schedulers on-the-fly. | |
2356 | */ | |
d9e7620e | 2357 | static int cfq_forced_dispatch(struct cfq_data *cfqd) |
1b5ed5e1 | 2358 | { |
0871714e | 2359 | struct cfq_queue *cfqq; |
d9e7620e | 2360 | int dispatched = 0; |
cdb16e8f | 2361 | |
3440c49f | 2362 | /* Expire the timeslice of the current active queue first */ |
e5ff082e | 2363 | cfq_slice_expired(cfqd, 0); |
3440c49f DS |
2364 | while ((cfqq = cfq_get_next_queue_forced(cfqd)) != NULL) { |
2365 | __cfq_set_active_queue(cfqd, cfqq); | |
f04a6424 | 2366 | dispatched += __cfq_forced_dispatch_cfqq(cfqq); |
3440c49f | 2367 | } |
1b5ed5e1 | 2368 | |
1b5ed5e1 TH |
2369 | BUG_ON(cfqd->busy_queues); |
2370 | ||
6923715a | 2371 | cfq_log(cfqd, "forced_dispatch=%d", dispatched); |
1b5ed5e1 TH |
2372 | return dispatched; |
2373 | } | |
2374 | ||
abc3c744 SL |
2375 | static inline bool cfq_slice_used_soon(struct cfq_data *cfqd, |
2376 | struct cfq_queue *cfqq) | |
2377 | { | |
2378 | /* the queue hasn't finished any request, can't estimate */ | |
2379 | if (cfq_cfqq_slice_new(cfqq)) | |
c1e44756 | 2380 | return true; |
abc3c744 SL |
2381 | if (time_after(jiffies + cfqd->cfq_slice_idle * cfqq->dispatched, |
2382 | cfqq->slice_end)) | |
c1e44756 | 2383 | return true; |
abc3c744 | 2384 | |
c1e44756 | 2385 | return false; |
abc3c744 SL |
2386 | } |
2387 | ||
0b182d61 | 2388 | static bool cfq_may_dispatch(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
2f5cb738 | 2389 | { |
2f5cb738 | 2390 | unsigned int max_dispatch; |
22e2c507 | 2391 | |
5ad531db JA |
2392 | /* |
2393 | * Drain async requests before we start sync IO | |
2394 | */ | |
53c583d2 | 2395 | if (cfq_should_idle(cfqd, cfqq) && cfqd->rq_in_flight[BLK_RW_ASYNC]) |
0b182d61 | 2396 | return false; |
5ad531db | 2397 | |
2f5cb738 JA |
2398 | /* |
2399 | * If this is an async queue and we have sync IO in flight, let it wait | |
2400 | */ | |
53c583d2 | 2401 | if (cfqd->rq_in_flight[BLK_RW_SYNC] && !cfq_cfqq_sync(cfqq)) |
0b182d61 | 2402 | return false; |
2f5cb738 | 2403 | |
abc3c744 | 2404 | max_dispatch = max_t(unsigned int, cfqd->cfq_quantum / 2, 1); |
2f5cb738 JA |
2405 | if (cfq_class_idle(cfqq)) |
2406 | max_dispatch = 1; | |
b4878f24 | 2407 | |
2f5cb738 JA |
2408 | /* |
2409 | * Does this cfqq already have too much IO in flight? | |
2410 | */ | |
2411 | if (cfqq->dispatched >= max_dispatch) { | |
ef8a41df | 2412 | bool promote_sync = false; |
2f5cb738 JA |
2413 | /* |
2414 | * idle queue must always only have a single IO in flight | |
2415 | */ | |
3ed9a296 | 2416 | if (cfq_class_idle(cfqq)) |
0b182d61 | 2417 | return false; |
3ed9a296 | 2418 | |
ef8a41df | 2419 | /* |
c4ade94f LS |
2420 | * If there is only one sync queue |
2421 | * we can ignore async queue here and give the sync | |
ef8a41df SL |
2422 | * queue no dispatch limit. The reason is a sync queue can |
2423 | * preempt async queue, limiting the sync queue doesn't make | |
2424 | * sense. This is useful for aiostress test. | |
2425 | */ | |
c4ade94f LS |
2426 | if (cfq_cfqq_sync(cfqq) && cfqd->busy_sync_queues == 1) |
2427 | promote_sync = true; | |
ef8a41df | 2428 | |
2f5cb738 JA |
2429 | /* |
2430 | * We have other queues, don't allow more IO from this one | |
2431 | */ | |
ef8a41df SL |
2432 | if (cfqd->busy_queues > 1 && cfq_slice_used_soon(cfqd, cfqq) && |
2433 | !promote_sync) | |
0b182d61 | 2434 | return false; |
9ede209e | 2435 | |
365722bb | 2436 | /* |
474b18cc | 2437 | * Sole queue user, no limit |
365722bb | 2438 | */ |
ef8a41df | 2439 | if (cfqd->busy_queues == 1 || promote_sync) |
abc3c744 SL |
2440 | max_dispatch = -1; |
2441 | else | |
2442 | /* | |
2443 | * Normally we start throttling cfqq when cfq_quantum/2 | |
2444 | * requests have been dispatched. But we can drive | |
2445 | * deeper queue depths at the beginning of slice | |
2446 | * subjected to upper limit of cfq_quantum. | |
2447 | * */ | |
2448 | max_dispatch = cfqd->cfq_quantum; | |
8e296755 JA |
2449 | } |
2450 | ||
2451 | /* | |
2452 | * Async queues must wait a bit before being allowed dispatch. | |
2453 | * We also ramp up the dispatch depth gradually for async IO, | |
2454 | * based on the last sync IO we serviced | |
2455 | */ | |
963b72fc | 2456 | if (!cfq_cfqq_sync(cfqq) && cfqd->cfq_latency) { |
573412b2 | 2457 | unsigned long last_sync = jiffies - cfqd->last_delayed_sync; |
8e296755 | 2458 | unsigned int depth; |
365722bb | 2459 | |
61f0c1dc | 2460 | depth = last_sync / cfqd->cfq_slice[1]; |
e00c54c3 JA |
2461 | if (!depth && !cfqq->dispatched) |
2462 | depth = 1; | |
8e296755 JA |
2463 | if (depth < max_dispatch) |
2464 | max_dispatch = depth; | |
2f5cb738 | 2465 | } |
3ed9a296 | 2466 | |
0b182d61 JA |
2467 | /* |
2468 | * If we're below the current max, allow a dispatch | |
2469 | */ | |
2470 | return cfqq->dispatched < max_dispatch; | |
2471 | } | |
2472 | ||
2473 | /* | |
2474 | * Dispatch a request from cfqq, moving them to the request queue | |
2475 | * dispatch list. | |
2476 | */ | |
2477 | static bool cfq_dispatch_request(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
2478 | { | |
2479 | struct request *rq; | |
2480 | ||
2481 | BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list)); | |
2482 | ||
2483 | if (!cfq_may_dispatch(cfqd, cfqq)) | |
2484 | return false; | |
2485 | ||
2486 | /* | |
2487 | * follow expired path, else get first next available | |
2488 | */ | |
2489 | rq = cfq_check_fifo(cfqq); | |
2490 | if (!rq) | |
2491 | rq = cfqq->next_rq; | |
2492 | ||
2493 | /* | |
2494 | * insert request into driver dispatch list | |
2495 | */ | |
2496 | cfq_dispatch_insert(cfqd->queue, rq); | |
2497 | ||
2498 | if (!cfqd->active_cic) { | |
2499 | struct cfq_io_context *cic = RQ_CIC(rq); | |
2500 | ||
2501 | atomic_long_inc(&cic->ioc->refcount); | |
2502 | cfqd->active_cic = cic; | |
2503 | } | |
2504 | ||
2505 | return true; | |
2506 | } | |
2507 | ||
2508 | /* | |
2509 | * Find the cfqq that we need to service and move a request from that to the | |
2510 | * dispatch list | |
2511 | */ | |
2512 | static int cfq_dispatch_requests(struct request_queue *q, int force) | |
2513 | { | |
2514 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
2515 | struct cfq_queue *cfqq; | |
2516 | ||
2517 | if (!cfqd->busy_queues) | |
2518 | return 0; | |
2519 | ||
2520 | if (unlikely(force)) | |
2521 | return cfq_forced_dispatch(cfqd); | |
2522 | ||
2523 | cfqq = cfq_select_queue(cfqd); | |
2524 | if (!cfqq) | |
8e296755 JA |
2525 | return 0; |
2526 | ||
2f5cb738 | 2527 | /* |
0b182d61 | 2528 | * Dispatch a request from this cfqq, if it is allowed |
2f5cb738 | 2529 | */ |
0b182d61 JA |
2530 | if (!cfq_dispatch_request(cfqd, cfqq)) |
2531 | return 0; | |
2532 | ||
2f5cb738 | 2533 | cfqq->slice_dispatch++; |
b029195d | 2534 | cfq_clear_cfqq_must_dispatch(cfqq); |
22e2c507 | 2535 | |
2f5cb738 JA |
2536 | /* |
2537 | * expire an async queue immediately if it has used up its slice. idle | |
2538 | * queue always expire after 1 dispatch round. | |
2539 | */ | |
2540 | if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) && | |
2541 | cfqq->slice_dispatch >= cfq_prio_to_maxrq(cfqd, cfqq)) || | |
2542 | cfq_class_idle(cfqq))) { | |
2543 | cfqq->slice_end = jiffies + 1; | |
e5ff082e | 2544 | cfq_slice_expired(cfqd, 0); |
1da177e4 LT |
2545 | } |
2546 | ||
b217a903 | 2547 | cfq_log_cfqq(cfqd, cfqq, "dispatched a request"); |
2f5cb738 | 2548 | return 1; |
1da177e4 LT |
2549 | } |
2550 | ||
1da177e4 | 2551 | /* |
5e705374 JA |
2552 | * task holds one reference to the queue, dropped when task exits. each rq |
2553 | * in-flight on this queue also holds a reference, dropped when rq is freed. | |
1da177e4 | 2554 | * |
b1c35769 | 2555 | * Each cfq queue took a reference on the parent group. Drop it now. |
1da177e4 LT |
2556 | * queue lock must be held here. |
2557 | */ | |
2558 | static void cfq_put_queue(struct cfq_queue *cfqq) | |
2559 | { | |
22e2c507 | 2560 | struct cfq_data *cfqd = cfqq->cfqd; |
0bbfeb83 | 2561 | struct cfq_group *cfqg; |
22e2c507 | 2562 | |
30d7b944 | 2563 | BUG_ON(cfqq->ref <= 0); |
1da177e4 | 2564 | |
30d7b944 SL |
2565 | cfqq->ref--; |
2566 | if (cfqq->ref) | |
1da177e4 LT |
2567 | return; |
2568 | ||
7b679138 | 2569 | cfq_log_cfqq(cfqd, cfqq, "put_queue"); |
1da177e4 | 2570 | BUG_ON(rb_first(&cfqq->sort_list)); |
22e2c507 | 2571 | BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]); |
b1c35769 | 2572 | cfqg = cfqq->cfqg; |
1da177e4 | 2573 | |
28f95cbc | 2574 | if (unlikely(cfqd->active_queue == cfqq)) { |
e5ff082e | 2575 | __cfq_slice_expired(cfqd, cfqq, 0); |
23e018a1 | 2576 | cfq_schedule_dispatch(cfqd); |
28f95cbc | 2577 | } |
22e2c507 | 2578 | |
f04a6424 | 2579 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
1da177e4 | 2580 | kmem_cache_free(cfq_pool, cfqq); |
b1c35769 | 2581 | cfq_put_cfqg(cfqg); |
1da177e4 LT |
2582 | } |
2583 | ||
d6de8be7 JA |
2584 | /* |
2585 | * Must always be called with the rcu_read_lock() held | |
2586 | */ | |
07416d29 JA |
2587 | static void |
2588 | __call_for_each_cic(struct io_context *ioc, | |
2589 | void (*func)(struct io_context *, struct cfq_io_context *)) | |
2590 | { | |
2591 | struct cfq_io_context *cic; | |
2592 | struct hlist_node *n; | |
2593 | ||
2594 | hlist_for_each_entry_rcu(cic, n, &ioc->cic_list, cic_list) | |
2595 | func(ioc, cic); | |
2596 | } | |
2597 | ||
4ac845a2 | 2598 | /* |
34e6bbf2 | 2599 | * Call func for each cic attached to this ioc. |
4ac845a2 | 2600 | */ |
34e6bbf2 | 2601 | static void |
4ac845a2 JA |
2602 | call_for_each_cic(struct io_context *ioc, |
2603 | void (*func)(struct io_context *, struct cfq_io_context *)) | |
1da177e4 | 2604 | { |
4ac845a2 | 2605 | rcu_read_lock(); |
07416d29 | 2606 | __call_for_each_cic(ioc, func); |
4ac845a2 | 2607 | rcu_read_unlock(); |
34e6bbf2 FC |
2608 | } |
2609 | ||
2610 | static void cfq_cic_free_rcu(struct rcu_head *head) | |
2611 | { | |
2612 | struct cfq_io_context *cic; | |
2613 | ||
2614 | cic = container_of(head, struct cfq_io_context, rcu_head); | |
2615 | ||
2616 | kmem_cache_free(cfq_ioc_pool, cic); | |
245b2e70 | 2617 | elv_ioc_count_dec(cfq_ioc_count); |
34e6bbf2 | 2618 | |
9a11b4ed JA |
2619 | if (ioc_gone) { |
2620 | /* | |
2621 | * CFQ scheduler is exiting, grab exit lock and check | |
2622 | * the pending io context count. If it hits zero, | |
2623 | * complete ioc_gone and set it back to NULL | |
2624 | */ | |
2625 | spin_lock(&ioc_gone_lock); | |
245b2e70 | 2626 | if (ioc_gone && !elv_ioc_count_read(cfq_ioc_count)) { |
9a11b4ed JA |
2627 | complete(ioc_gone); |
2628 | ioc_gone = NULL; | |
2629 | } | |
2630 | spin_unlock(&ioc_gone_lock); | |
2631 | } | |
34e6bbf2 | 2632 | } |
4ac845a2 | 2633 | |
34e6bbf2 FC |
2634 | static void cfq_cic_free(struct cfq_io_context *cic) |
2635 | { | |
2636 | call_rcu(&cic->rcu_head, cfq_cic_free_rcu); | |
4ac845a2 JA |
2637 | } |
2638 | ||
2639 | static void cic_free_func(struct io_context *ioc, struct cfq_io_context *cic) | |
2640 | { | |
2641 | unsigned long flags; | |
bca4b914 | 2642 | unsigned long dead_key = (unsigned long) cic->key; |
4ac845a2 | 2643 | |
bca4b914 | 2644 | BUG_ON(!(dead_key & CIC_DEAD_KEY)); |
4ac845a2 JA |
2645 | |
2646 | spin_lock_irqsave(&ioc->lock, flags); | |
80b15c73 | 2647 | radix_tree_delete(&ioc->radix_root, dead_key >> CIC_DEAD_INDEX_SHIFT); |
ffc4e759 | 2648 | hlist_del_rcu(&cic->cic_list); |
4ac845a2 JA |
2649 | spin_unlock_irqrestore(&ioc->lock, flags); |
2650 | ||
34e6bbf2 | 2651 | cfq_cic_free(cic); |
4ac845a2 JA |
2652 | } |
2653 | ||
d6de8be7 JA |
2654 | /* |
2655 | * Must be called with rcu_read_lock() held or preemption otherwise disabled. | |
2656 | * Only two callers of this - ->dtor() which is called with the rcu_read_lock(), | |
2657 | * and ->trim() which is called with the task lock held | |
2658 | */ | |
4ac845a2 JA |
2659 | static void cfq_free_io_context(struct io_context *ioc) |
2660 | { | |
4ac845a2 | 2661 | /* |
34e6bbf2 FC |
2662 | * ioc->refcount is zero here, or we are called from elv_unregister(), |
2663 | * so no more cic's are allowed to be linked into this ioc. So it | |
2664 | * should be ok to iterate over the known list, we will see all cic's | |
2665 | * since no new ones are added. | |
4ac845a2 | 2666 | */ |
07416d29 | 2667 | __call_for_each_cic(ioc, cic_free_func); |
1da177e4 LT |
2668 | } |
2669 | ||
d02a2c07 | 2670 | static void cfq_put_cooperator(struct cfq_queue *cfqq) |
1da177e4 | 2671 | { |
df5fe3e8 JM |
2672 | struct cfq_queue *__cfqq, *next; |
2673 | ||
df5fe3e8 JM |
2674 | /* |
2675 | * If this queue was scheduled to merge with another queue, be | |
2676 | * sure to drop the reference taken on that queue (and others in | |
2677 | * the merge chain). See cfq_setup_merge and cfq_merge_cfqqs. | |
2678 | */ | |
2679 | __cfqq = cfqq->new_cfqq; | |
2680 | while (__cfqq) { | |
2681 | if (__cfqq == cfqq) { | |
2682 | WARN(1, "cfqq->new_cfqq loop detected\n"); | |
2683 | break; | |
2684 | } | |
2685 | next = __cfqq->new_cfqq; | |
2686 | cfq_put_queue(__cfqq); | |
2687 | __cfqq = next; | |
2688 | } | |
d02a2c07 SL |
2689 | } |
2690 | ||
2691 | static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
2692 | { | |
2693 | if (unlikely(cfqq == cfqd->active_queue)) { | |
2694 | __cfq_slice_expired(cfqd, cfqq, 0); | |
2695 | cfq_schedule_dispatch(cfqd); | |
2696 | } | |
2697 | ||
2698 | cfq_put_cooperator(cfqq); | |
df5fe3e8 | 2699 | |
89850f7e JA |
2700 | cfq_put_queue(cfqq); |
2701 | } | |
22e2c507 | 2702 | |
89850f7e JA |
2703 | static void __cfq_exit_single_io_context(struct cfq_data *cfqd, |
2704 | struct cfq_io_context *cic) | |
2705 | { | |
4faa3c81 FC |
2706 | struct io_context *ioc = cic->ioc; |
2707 | ||
fc46379d | 2708 | list_del_init(&cic->queue_list); |
4ac845a2 JA |
2709 | |
2710 | /* | |
bca4b914 | 2711 | * Make sure dead mark is seen for dead queues |
4ac845a2 | 2712 | */ |
fc46379d | 2713 | smp_wmb(); |
bca4b914 | 2714 | cic->key = cfqd_dead_key(cfqd); |
fc46379d | 2715 | |
4faa3c81 FC |
2716 | if (ioc->ioc_data == cic) |
2717 | rcu_assign_pointer(ioc->ioc_data, NULL); | |
2718 | ||
ff6657c6 JA |
2719 | if (cic->cfqq[BLK_RW_ASYNC]) { |
2720 | cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_ASYNC]); | |
2721 | cic->cfqq[BLK_RW_ASYNC] = NULL; | |
12a05732 AV |
2722 | } |
2723 | ||
ff6657c6 JA |
2724 | if (cic->cfqq[BLK_RW_SYNC]) { |
2725 | cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_SYNC]); | |
2726 | cic->cfqq[BLK_RW_SYNC] = NULL; | |
12a05732 | 2727 | } |
89850f7e JA |
2728 | } |
2729 | ||
4ac845a2 JA |
2730 | static void cfq_exit_single_io_context(struct io_context *ioc, |
2731 | struct cfq_io_context *cic) | |
89850f7e | 2732 | { |
bca4b914 | 2733 | struct cfq_data *cfqd = cic_to_cfqd(cic); |
89850f7e | 2734 | |
89850f7e | 2735 | if (cfqd) { |
165125e1 | 2736 | struct request_queue *q = cfqd->queue; |
4ac845a2 | 2737 | unsigned long flags; |
89850f7e | 2738 | |
4ac845a2 | 2739 | spin_lock_irqsave(q->queue_lock, flags); |
62c1fe9d JA |
2740 | |
2741 | /* | |
2742 | * Ensure we get a fresh copy of the ->key to prevent | |
2743 | * race between exiting task and queue | |
2744 | */ | |
2745 | smp_read_barrier_depends(); | |
bca4b914 | 2746 | if (cic->key == cfqd) |
62c1fe9d JA |
2747 | __cfq_exit_single_io_context(cfqd, cic); |
2748 | ||
4ac845a2 | 2749 | spin_unlock_irqrestore(q->queue_lock, flags); |
89850f7e | 2750 | } |
1da177e4 LT |
2751 | } |
2752 | ||
498d3aa2 JA |
2753 | /* |
2754 | * The process that ioc belongs to has exited, we need to clean up | |
2755 | * and put the internal structures we have that belongs to that process. | |
2756 | */ | |
e2d74ac0 | 2757 | static void cfq_exit_io_context(struct io_context *ioc) |
1da177e4 | 2758 | { |
4ac845a2 | 2759 | call_for_each_cic(ioc, cfq_exit_single_io_context); |
1da177e4 LT |
2760 | } |
2761 | ||
22e2c507 | 2762 | static struct cfq_io_context * |
8267e268 | 2763 | cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
1da177e4 | 2764 | { |
b5deef90 | 2765 | struct cfq_io_context *cic; |
1da177e4 | 2766 | |
94f6030c CL |
2767 | cic = kmem_cache_alloc_node(cfq_ioc_pool, gfp_mask | __GFP_ZERO, |
2768 | cfqd->queue->node); | |
1da177e4 | 2769 | if (cic) { |
22e2c507 | 2770 | cic->last_end_request = jiffies; |
553698f9 | 2771 | INIT_LIST_HEAD(&cic->queue_list); |
ffc4e759 | 2772 | INIT_HLIST_NODE(&cic->cic_list); |
22e2c507 JA |
2773 | cic->dtor = cfq_free_io_context; |
2774 | cic->exit = cfq_exit_io_context; | |
245b2e70 | 2775 | elv_ioc_count_inc(cfq_ioc_count); |
1da177e4 LT |
2776 | } |
2777 | ||
2778 | return cic; | |
2779 | } | |
2780 | ||
fd0928df | 2781 | static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc) |
22e2c507 JA |
2782 | { |
2783 | struct task_struct *tsk = current; | |
2784 | int ioprio_class; | |
2785 | ||
3b18152c | 2786 | if (!cfq_cfqq_prio_changed(cfqq)) |
22e2c507 JA |
2787 | return; |
2788 | ||
fd0928df | 2789 | ioprio_class = IOPRIO_PRIO_CLASS(ioc->ioprio); |
22e2c507 | 2790 | switch (ioprio_class) { |
fe094d98 JA |
2791 | default: |
2792 | printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class); | |
2793 | case IOPRIO_CLASS_NONE: | |
2794 | /* | |
6d63c275 | 2795 | * no prio set, inherit CPU scheduling settings |
fe094d98 JA |
2796 | */ |
2797 | cfqq->ioprio = task_nice_ioprio(tsk); | |
6d63c275 | 2798 | cfqq->ioprio_class = task_nice_ioclass(tsk); |
fe094d98 JA |
2799 | break; |
2800 | case IOPRIO_CLASS_RT: | |
2801 | cfqq->ioprio = task_ioprio(ioc); | |
2802 | cfqq->ioprio_class = IOPRIO_CLASS_RT; | |
2803 | break; | |
2804 | case IOPRIO_CLASS_BE: | |
2805 | cfqq->ioprio = task_ioprio(ioc); | |
2806 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
2807 | break; | |
2808 | case IOPRIO_CLASS_IDLE: | |
2809 | cfqq->ioprio_class = IOPRIO_CLASS_IDLE; | |
2810 | cfqq->ioprio = 7; | |
2811 | cfq_clear_cfqq_idle_window(cfqq); | |
2812 | break; | |
22e2c507 JA |
2813 | } |
2814 | ||
2815 | /* | |
2816 | * keep track of original prio settings in case we have to temporarily | |
2817 | * elevate the priority of this queue | |
2818 | */ | |
2819 | cfqq->org_ioprio = cfqq->ioprio; | |
2820 | cfqq->org_ioprio_class = cfqq->ioprio_class; | |
3b18152c | 2821 | cfq_clear_cfqq_prio_changed(cfqq); |
22e2c507 JA |
2822 | } |
2823 | ||
febffd61 | 2824 | static void changed_ioprio(struct io_context *ioc, struct cfq_io_context *cic) |
22e2c507 | 2825 | { |
bca4b914 | 2826 | struct cfq_data *cfqd = cic_to_cfqd(cic); |
478a82b0 | 2827 | struct cfq_queue *cfqq; |
c1b707d2 | 2828 | unsigned long flags; |
35e6077c | 2829 | |
caaa5f9f JA |
2830 | if (unlikely(!cfqd)) |
2831 | return; | |
2832 | ||
c1b707d2 | 2833 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); |
caaa5f9f | 2834 | |
ff6657c6 | 2835 | cfqq = cic->cfqq[BLK_RW_ASYNC]; |
caaa5f9f JA |
2836 | if (cfqq) { |
2837 | struct cfq_queue *new_cfqq; | |
ff6657c6 JA |
2838 | new_cfqq = cfq_get_queue(cfqd, BLK_RW_ASYNC, cic->ioc, |
2839 | GFP_ATOMIC); | |
caaa5f9f | 2840 | if (new_cfqq) { |
ff6657c6 | 2841 | cic->cfqq[BLK_RW_ASYNC] = new_cfqq; |
caaa5f9f JA |
2842 | cfq_put_queue(cfqq); |
2843 | } | |
22e2c507 | 2844 | } |
caaa5f9f | 2845 | |
ff6657c6 | 2846 | cfqq = cic->cfqq[BLK_RW_SYNC]; |
caaa5f9f JA |
2847 | if (cfqq) |
2848 | cfq_mark_cfqq_prio_changed(cfqq); | |
2849 | ||
c1b707d2 | 2850 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); |
22e2c507 JA |
2851 | } |
2852 | ||
fc46379d | 2853 | static void cfq_ioc_set_ioprio(struct io_context *ioc) |
22e2c507 | 2854 | { |
4ac845a2 | 2855 | call_for_each_cic(ioc, changed_ioprio); |
fc46379d | 2856 | ioc->ioprio_changed = 0; |
22e2c507 JA |
2857 | } |
2858 | ||
d5036d77 | 2859 | static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
a6151c3a | 2860 | pid_t pid, bool is_sync) |
d5036d77 JA |
2861 | { |
2862 | RB_CLEAR_NODE(&cfqq->rb_node); | |
2863 | RB_CLEAR_NODE(&cfqq->p_node); | |
2864 | INIT_LIST_HEAD(&cfqq->fifo); | |
2865 | ||
30d7b944 | 2866 | cfqq->ref = 0; |
d5036d77 JA |
2867 | cfqq->cfqd = cfqd; |
2868 | ||
2869 | cfq_mark_cfqq_prio_changed(cfqq); | |
2870 | ||
2871 | if (is_sync) { | |
2872 | if (!cfq_class_idle(cfqq)) | |
2873 | cfq_mark_cfqq_idle_window(cfqq); | |
2874 | cfq_mark_cfqq_sync(cfqq); | |
2875 | } | |
2876 | cfqq->pid = pid; | |
2877 | } | |
2878 | ||
24610333 VG |
2879 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
2880 | static void changed_cgroup(struct io_context *ioc, struct cfq_io_context *cic) | |
2881 | { | |
2882 | struct cfq_queue *sync_cfqq = cic_to_cfqq(cic, 1); | |
bca4b914 | 2883 | struct cfq_data *cfqd = cic_to_cfqd(cic); |
24610333 VG |
2884 | unsigned long flags; |
2885 | struct request_queue *q; | |
2886 | ||
2887 | if (unlikely(!cfqd)) | |
2888 | return; | |
2889 | ||
2890 | q = cfqd->queue; | |
2891 | ||
2892 | spin_lock_irqsave(q->queue_lock, flags); | |
2893 | ||
2894 | if (sync_cfqq) { | |
2895 | /* | |
2896 | * Drop reference to sync queue. A new sync queue will be | |
2897 | * assigned in new group upon arrival of a fresh request. | |
2898 | */ | |
2899 | cfq_log_cfqq(cfqd, sync_cfqq, "changed cgroup"); | |
2900 | cic_set_cfqq(cic, NULL, 1); | |
2901 | cfq_put_queue(sync_cfqq); | |
2902 | } | |
2903 | ||
2904 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2905 | } | |
2906 | ||
2907 | static void cfq_ioc_set_cgroup(struct io_context *ioc) | |
2908 | { | |
2909 | call_for_each_cic(ioc, changed_cgroup); | |
2910 | ioc->cgroup_changed = 0; | |
2911 | } | |
2912 | #endif /* CONFIG_CFQ_GROUP_IOSCHED */ | |
2913 | ||
22e2c507 | 2914 | static struct cfq_queue * |
a6151c3a | 2915 | cfq_find_alloc_queue(struct cfq_data *cfqd, bool is_sync, |
fd0928df | 2916 | struct io_context *ioc, gfp_t gfp_mask) |
22e2c507 | 2917 | { |
22e2c507 | 2918 | struct cfq_queue *cfqq, *new_cfqq = NULL; |
91fac317 | 2919 | struct cfq_io_context *cic; |
cdb16e8f | 2920 | struct cfq_group *cfqg; |
22e2c507 JA |
2921 | |
2922 | retry: | |
cdb16e8f | 2923 | cfqg = cfq_get_cfqg(cfqd, 1); |
4ac845a2 | 2924 | cic = cfq_cic_lookup(cfqd, ioc); |
91fac317 VT |
2925 | /* cic always exists here */ |
2926 | cfqq = cic_to_cfqq(cic, is_sync); | |
22e2c507 | 2927 | |
6118b70b JA |
2928 | /* |
2929 | * Always try a new alloc if we fell back to the OOM cfqq | |
2930 | * originally, since it should just be a temporary situation. | |
2931 | */ | |
2932 | if (!cfqq || cfqq == &cfqd->oom_cfqq) { | |
2933 | cfqq = NULL; | |
22e2c507 JA |
2934 | if (new_cfqq) { |
2935 | cfqq = new_cfqq; | |
2936 | new_cfqq = NULL; | |
2937 | } else if (gfp_mask & __GFP_WAIT) { | |
2938 | spin_unlock_irq(cfqd->queue->queue_lock); | |
94f6030c | 2939 | new_cfqq = kmem_cache_alloc_node(cfq_pool, |
6118b70b | 2940 | gfp_mask | __GFP_ZERO, |
94f6030c | 2941 | cfqd->queue->node); |
22e2c507 | 2942 | spin_lock_irq(cfqd->queue->queue_lock); |
6118b70b JA |
2943 | if (new_cfqq) |
2944 | goto retry; | |
22e2c507 | 2945 | } else { |
94f6030c CL |
2946 | cfqq = kmem_cache_alloc_node(cfq_pool, |
2947 | gfp_mask | __GFP_ZERO, | |
2948 | cfqd->queue->node); | |
22e2c507 JA |
2949 | } |
2950 | ||
6118b70b JA |
2951 | if (cfqq) { |
2952 | cfq_init_cfqq(cfqd, cfqq, current->pid, is_sync); | |
2953 | cfq_init_prio_data(cfqq, ioc); | |
cdb16e8f | 2954 | cfq_link_cfqq_cfqg(cfqq, cfqg); |
6118b70b JA |
2955 | cfq_log_cfqq(cfqd, cfqq, "alloced"); |
2956 | } else | |
2957 | cfqq = &cfqd->oom_cfqq; | |
22e2c507 JA |
2958 | } |
2959 | ||
2960 | if (new_cfqq) | |
2961 | kmem_cache_free(cfq_pool, new_cfqq); | |
2962 | ||
22e2c507 JA |
2963 | return cfqq; |
2964 | } | |
2965 | ||
c2dea2d1 VT |
2966 | static struct cfq_queue ** |
2967 | cfq_async_queue_prio(struct cfq_data *cfqd, int ioprio_class, int ioprio) | |
2968 | { | |
fe094d98 | 2969 | switch (ioprio_class) { |
c2dea2d1 VT |
2970 | case IOPRIO_CLASS_RT: |
2971 | return &cfqd->async_cfqq[0][ioprio]; | |
2972 | case IOPRIO_CLASS_BE: | |
2973 | return &cfqd->async_cfqq[1][ioprio]; | |
2974 | case IOPRIO_CLASS_IDLE: | |
2975 | return &cfqd->async_idle_cfqq; | |
2976 | default: | |
2977 | BUG(); | |
2978 | } | |
2979 | } | |
2980 | ||
15c31be4 | 2981 | static struct cfq_queue * |
a6151c3a | 2982 | cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct io_context *ioc, |
15c31be4 JA |
2983 | gfp_t gfp_mask) |
2984 | { | |
fd0928df JA |
2985 | const int ioprio = task_ioprio(ioc); |
2986 | const int ioprio_class = task_ioprio_class(ioc); | |
c2dea2d1 | 2987 | struct cfq_queue **async_cfqq = NULL; |
15c31be4 JA |
2988 | struct cfq_queue *cfqq = NULL; |
2989 | ||
c2dea2d1 VT |
2990 | if (!is_sync) { |
2991 | async_cfqq = cfq_async_queue_prio(cfqd, ioprio_class, ioprio); | |
2992 | cfqq = *async_cfqq; | |
2993 | } | |
2994 | ||
6118b70b | 2995 | if (!cfqq) |
fd0928df | 2996 | cfqq = cfq_find_alloc_queue(cfqd, is_sync, ioc, gfp_mask); |
15c31be4 JA |
2997 | |
2998 | /* | |
2999 | * pin the queue now that it's allocated, scheduler exit will prune it | |
3000 | */ | |
c2dea2d1 | 3001 | if (!is_sync && !(*async_cfqq)) { |
30d7b944 | 3002 | cfqq->ref++; |
c2dea2d1 | 3003 | *async_cfqq = cfqq; |
15c31be4 JA |
3004 | } |
3005 | ||
30d7b944 | 3006 | cfqq->ref++; |
15c31be4 JA |
3007 | return cfqq; |
3008 | } | |
3009 | ||
498d3aa2 JA |
3010 | /* |
3011 | * We drop cfq io contexts lazily, so we may find a dead one. | |
3012 | */ | |
dbecf3ab | 3013 | static void |
4ac845a2 JA |
3014 | cfq_drop_dead_cic(struct cfq_data *cfqd, struct io_context *ioc, |
3015 | struct cfq_io_context *cic) | |
dbecf3ab | 3016 | { |
4ac845a2 JA |
3017 | unsigned long flags; |
3018 | ||
fc46379d | 3019 | WARN_ON(!list_empty(&cic->queue_list)); |
bca4b914 | 3020 | BUG_ON(cic->key != cfqd_dead_key(cfqd)); |
597bc485 | 3021 | |
4ac845a2 JA |
3022 | spin_lock_irqsave(&ioc->lock, flags); |
3023 | ||
4faa3c81 | 3024 | BUG_ON(ioc->ioc_data == cic); |
597bc485 | 3025 | |
80b15c73 | 3026 | radix_tree_delete(&ioc->radix_root, cfqd->cic_index); |
ffc4e759 | 3027 | hlist_del_rcu(&cic->cic_list); |
4ac845a2 JA |
3028 | spin_unlock_irqrestore(&ioc->lock, flags); |
3029 | ||
3030 | cfq_cic_free(cic); | |
dbecf3ab OH |
3031 | } |
3032 | ||
e2d74ac0 | 3033 | static struct cfq_io_context * |
4ac845a2 | 3034 | cfq_cic_lookup(struct cfq_data *cfqd, struct io_context *ioc) |
e2d74ac0 | 3035 | { |
e2d74ac0 | 3036 | struct cfq_io_context *cic; |
d6de8be7 | 3037 | unsigned long flags; |
e2d74ac0 | 3038 | |
91fac317 VT |
3039 | if (unlikely(!ioc)) |
3040 | return NULL; | |
3041 | ||
d6de8be7 JA |
3042 | rcu_read_lock(); |
3043 | ||
597bc485 JA |
3044 | /* |
3045 | * we maintain a last-hit cache, to avoid browsing over the tree | |
3046 | */ | |
4ac845a2 | 3047 | cic = rcu_dereference(ioc->ioc_data); |
d6de8be7 JA |
3048 | if (cic && cic->key == cfqd) { |
3049 | rcu_read_unlock(); | |
597bc485 | 3050 | return cic; |
d6de8be7 | 3051 | } |
597bc485 | 3052 | |
4ac845a2 | 3053 | do { |
80b15c73 | 3054 | cic = radix_tree_lookup(&ioc->radix_root, cfqd->cic_index); |
4ac845a2 JA |
3055 | rcu_read_unlock(); |
3056 | if (!cic) | |
3057 | break; | |
bca4b914 | 3058 | if (unlikely(cic->key != cfqd)) { |
4ac845a2 | 3059 | cfq_drop_dead_cic(cfqd, ioc, cic); |
d6de8be7 | 3060 | rcu_read_lock(); |
4ac845a2 | 3061 | continue; |
dbecf3ab | 3062 | } |
e2d74ac0 | 3063 | |
d6de8be7 | 3064 | spin_lock_irqsave(&ioc->lock, flags); |
4ac845a2 | 3065 | rcu_assign_pointer(ioc->ioc_data, cic); |
d6de8be7 | 3066 | spin_unlock_irqrestore(&ioc->lock, flags); |
4ac845a2 JA |
3067 | break; |
3068 | } while (1); | |
e2d74ac0 | 3069 | |
4ac845a2 | 3070 | return cic; |
e2d74ac0 JA |
3071 | } |
3072 | ||
4ac845a2 JA |
3073 | /* |
3074 | * Add cic into ioc, using cfqd as the search key. This enables us to lookup | |
3075 | * the process specific cfq io context when entered from the block layer. | |
3076 | * Also adds the cic to a per-cfqd list, used when this queue is removed. | |
3077 | */ | |
febffd61 JA |
3078 | static int cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc, |
3079 | struct cfq_io_context *cic, gfp_t gfp_mask) | |
e2d74ac0 | 3080 | { |
0261d688 | 3081 | unsigned long flags; |
4ac845a2 | 3082 | int ret; |
e2d74ac0 | 3083 | |
4ac845a2 JA |
3084 | ret = radix_tree_preload(gfp_mask); |
3085 | if (!ret) { | |
3086 | cic->ioc = ioc; | |
3087 | cic->key = cfqd; | |
e2d74ac0 | 3088 | |
4ac845a2 JA |
3089 | spin_lock_irqsave(&ioc->lock, flags); |
3090 | ret = radix_tree_insert(&ioc->radix_root, | |
80b15c73 | 3091 | cfqd->cic_index, cic); |
ffc4e759 JA |
3092 | if (!ret) |
3093 | hlist_add_head_rcu(&cic->cic_list, &ioc->cic_list); | |
4ac845a2 | 3094 | spin_unlock_irqrestore(&ioc->lock, flags); |
e2d74ac0 | 3095 | |
4ac845a2 JA |
3096 | radix_tree_preload_end(); |
3097 | ||
3098 | if (!ret) { | |
3099 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
3100 | list_add(&cic->queue_list, &cfqd->cic_list); | |
3101 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
3102 | } | |
e2d74ac0 JA |
3103 | } |
3104 | ||
4ac845a2 JA |
3105 | if (ret) |
3106 | printk(KERN_ERR "cfq: cic link failed!\n"); | |
fc46379d | 3107 | |
4ac845a2 | 3108 | return ret; |
e2d74ac0 JA |
3109 | } |
3110 | ||
1da177e4 LT |
3111 | /* |
3112 | * Setup general io context and cfq io context. There can be several cfq | |
3113 | * io contexts per general io context, if this process is doing io to more | |
e2d74ac0 | 3114 | * than one device managed by cfq. |
1da177e4 LT |
3115 | */ |
3116 | static struct cfq_io_context * | |
e2d74ac0 | 3117 | cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
1da177e4 | 3118 | { |
22e2c507 | 3119 | struct io_context *ioc = NULL; |
1da177e4 | 3120 | struct cfq_io_context *cic; |
1da177e4 | 3121 | |
22e2c507 | 3122 | might_sleep_if(gfp_mask & __GFP_WAIT); |
1da177e4 | 3123 | |
b5deef90 | 3124 | ioc = get_io_context(gfp_mask, cfqd->queue->node); |
1da177e4 LT |
3125 | if (!ioc) |
3126 | return NULL; | |
3127 | ||
4ac845a2 | 3128 | cic = cfq_cic_lookup(cfqd, ioc); |
e2d74ac0 JA |
3129 | if (cic) |
3130 | goto out; | |
1da177e4 | 3131 | |
e2d74ac0 JA |
3132 | cic = cfq_alloc_io_context(cfqd, gfp_mask); |
3133 | if (cic == NULL) | |
3134 | goto err; | |
1da177e4 | 3135 | |
4ac845a2 JA |
3136 | if (cfq_cic_link(cfqd, ioc, cic, gfp_mask)) |
3137 | goto err_free; | |
3138 | ||
1da177e4 | 3139 | out: |
fc46379d JA |
3140 | smp_read_barrier_depends(); |
3141 | if (unlikely(ioc->ioprio_changed)) | |
3142 | cfq_ioc_set_ioprio(ioc); | |
3143 | ||
24610333 VG |
3144 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
3145 | if (unlikely(ioc->cgroup_changed)) | |
3146 | cfq_ioc_set_cgroup(ioc); | |
3147 | #endif | |
1da177e4 | 3148 | return cic; |
4ac845a2 JA |
3149 | err_free: |
3150 | cfq_cic_free(cic); | |
1da177e4 LT |
3151 | err: |
3152 | put_io_context(ioc); | |
3153 | return NULL; | |
3154 | } | |
3155 | ||
22e2c507 JA |
3156 | static void |
3157 | cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic) | |
1da177e4 | 3158 | { |
aaf1228d JA |
3159 | unsigned long elapsed = jiffies - cic->last_end_request; |
3160 | unsigned long ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle); | |
db3b5848 | 3161 | |
22e2c507 JA |
3162 | cic->ttime_samples = (7*cic->ttime_samples + 256) / 8; |
3163 | cic->ttime_total = (7*cic->ttime_total + 256*ttime) / 8; | |
3164 | cic->ttime_mean = (cic->ttime_total + 128) / cic->ttime_samples; | |
3165 | } | |
1da177e4 | 3166 | |
206dc69b | 3167 | static void |
b2c18e1e | 3168 | cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
6d048f53 | 3169 | struct request *rq) |
206dc69b | 3170 | { |
3dde36dd | 3171 | sector_t sdist = 0; |
41647e7a | 3172 | sector_t n_sec = blk_rq_sectors(rq); |
3dde36dd CZ |
3173 | if (cfqq->last_request_pos) { |
3174 | if (cfqq->last_request_pos < blk_rq_pos(rq)) | |
3175 | sdist = blk_rq_pos(rq) - cfqq->last_request_pos; | |
3176 | else | |
3177 | sdist = cfqq->last_request_pos - blk_rq_pos(rq); | |
3178 | } | |
206dc69b | 3179 | |
3dde36dd | 3180 | cfqq->seek_history <<= 1; |
41647e7a CZ |
3181 | if (blk_queue_nonrot(cfqd->queue)) |
3182 | cfqq->seek_history |= (n_sec < CFQQ_SECT_THR_NONROT); | |
3183 | else | |
3184 | cfqq->seek_history |= (sdist > CFQQ_SEEK_THR); | |
206dc69b | 3185 | } |
1da177e4 | 3186 | |
22e2c507 JA |
3187 | /* |
3188 | * Disable idle window if the process thinks too long or seeks so much that | |
3189 | * it doesn't matter | |
3190 | */ | |
3191 | static void | |
3192 | cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
3193 | struct cfq_io_context *cic) | |
3194 | { | |
7b679138 | 3195 | int old_idle, enable_idle; |
1be92f2f | 3196 | |
0871714e JA |
3197 | /* |
3198 | * Don't idle for async or idle io prio class | |
3199 | */ | |
3200 | if (!cfq_cfqq_sync(cfqq) || cfq_class_idle(cfqq)) | |
1be92f2f JA |
3201 | return; |
3202 | ||
c265a7f4 | 3203 | enable_idle = old_idle = cfq_cfqq_idle_window(cfqq); |
1da177e4 | 3204 | |
76280aff CZ |
3205 | if (cfqq->queued[0] + cfqq->queued[1] >= 4) |
3206 | cfq_mark_cfqq_deep(cfqq); | |
3207 | ||
749ef9f8 CZ |
3208 | if (cfqq->next_rq && (cfqq->next_rq->cmd_flags & REQ_NOIDLE)) |
3209 | enable_idle = 0; | |
3210 | else if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle || | |
3dde36dd | 3211 | (!cfq_cfqq_deep(cfqq) && CFQQ_SEEKY(cfqq))) |
22e2c507 JA |
3212 | enable_idle = 0; |
3213 | else if (sample_valid(cic->ttime_samples)) { | |
718eee05 | 3214 | if (cic->ttime_mean > cfqd->cfq_slice_idle) |
22e2c507 JA |
3215 | enable_idle = 0; |
3216 | else | |
3217 | enable_idle = 1; | |
1da177e4 LT |
3218 | } |
3219 | ||
7b679138 JA |
3220 | if (old_idle != enable_idle) { |
3221 | cfq_log_cfqq(cfqd, cfqq, "idle=%d", enable_idle); | |
3222 | if (enable_idle) | |
3223 | cfq_mark_cfqq_idle_window(cfqq); | |
3224 | else | |
3225 | cfq_clear_cfqq_idle_window(cfqq); | |
3226 | } | |
22e2c507 | 3227 | } |
1da177e4 | 3228 | |
22e2c507 JA |
3229 | /* |
3230 | * Check if new_cfqq should preempt the currently active queue. Return 0 for | |
3231 | * no or if we aren't sure, a 1 will cause a preempt. | |
3232 | */ | |
a6151c3a | 3233 | static bool |
22e2c507 | 3234 | cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, |
5e705374 | 3235 | struct request *rq) |
22e2c507 | 3236 | { |
6d048f53 | 3237 | struct cfq_queue *cfqq; |
22e2c507 | 3238 | |
6d048f53 JA |
3239 | cfqq = cfqd->active_queue; |
3240 | if (!cfqq) | |
a6151c3a | 3241 | return false; |
22e2c507 | 3242 | |
6d048f53 | 3243 | if (cfq_class_idle(new_cfqq)) |
a6151c3a | 3244 | return false; |
22e2c507 JA |
3245 | |
3246 | if (cfq_class_idle(cfqq)) | |
a6151c3a | 3247 | return true; |
1e3335de | 3248 | |
875feb63 DS |
3249 | /* |
3250 | * Don't allow a non-RT request to preempt an ongoing RT cfqq timeslice. | |
3251 | */ | |
3252 | if (cfq_class_rt(cfqq) && !cfq_class_rt(new_cfqq)) | |
3253 | return false; | |
3254 | ||
374f84ac JA |
3255 | /* |
3256 | * if the new request is sync, but the currently running queue is | |
3257 | * not, let the sync request have priority. | |
3258 | */ | |
5e705374 | 3259 | if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq)) |
a6151c3a | 3260 | return true; |
1e3335de | 3261 | |
8682e1f1 VG |
3262 | if (new_cfqq->cfqg != cfqq->cfqg) |
3263 | return false; | |
3264 | ||
3265 | if (cfq_slice_used(cfqq)) | |
3266 | return true; | |
3267 | ||
3268 | /* Allow preemption only if we are idling on sync-noidle tree */ | |
3269 | if (cfqd->serving_type == SYNC_NOIDLE_WORKLOAD && | |
3270 | cfqq_type(new_cfqq) == SYNC_NOIDLE_WORKLOAD && | |
3271 | new_cfqq->service_tree->count == 2 && | |
3272 | RB_EMPTY_ROOT(&cfqq->sort_list)) | |
3273 | return true; | |
3274 | ||
374f84ac JA |
3275 | /* |
3276 | * So both queues are sync. Let the new request get disk time if | |
3277 | * it's a metadata request and the current queue is doing regular IO. | |
3278 | */ | |
7b6d91da | 3279 | if ((rq->cmd_flags & REQ_META) && !cfqq->meta_pending) |
e6ec4fe2 | 3280 | return true; |
22e2c507 | 3281 | |
3a9a3f6c DS |
3282 | /* |
3283 | * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice. | |
3284 | */ | |
3285 | if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq)) | |
a6151c3a | 3286 | return true; |
3a9a3f6c | 3287 | |
d2d59e18 SL |
3288 | /* An idle queue should not be idle now for some reason */ |
3289 | if (RB_EMPTY_ROOT(&cfqq->sort_list) && !cfq_should_idle(cfqd, cfqq)) | |
3290 | return true; | |
3291 | ||
1e3335de | 3292 | if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq)) |
a6151c3a | 3293 | return false; |
1e3335de JA |
3294 | |
3295 | /* | |
3296 | * if this request is as-good as one we would expect from the | |
3297 | * current cfqq, let it preempt | |
3298 | */ | |
e9ce335d | 3299 | if (cfq_rq_close(cfqd, cfqq, rq)) |
a6151c3a | 3300 | return true; |
1e3335de | 3301 | |
a6151c3a | 3302 | return false; |
22e2c507 JA |
3303 | } |
3304 | ||
3305 | /* | |
3306 | * cfqq preempts the active queue. if we allowed preempt with no slice left, | |
3307 | * let it have half of its nominal slice. | |
3308 | */ | |
3309 | static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
3310 | { | |
f8ae6e3e SL |
3311 | struct cfq_queue *old_cfqq = cfqd->active_queue; |
3312 | ||
7b679138 | 3313 | cfq_log_cfqq(cfqd, cfqq, "preempt"); |
e5ff082e | 3314 | cfq_slice_expired(cfqd, 1); |
22e2c507 | 3315 | |
f8ae6e3e SL |
3316 | /* |
3317 | * workload type is changed, don't save slice, otherwise preempt | |
3318 | * doesn't happen | |
3319 | */ | |
3320 | if (cfqq_type(old_cfqq) != cfqq_type(cfqq)) | |
3321 | cfqq->cfqg->saved_workload_slice = 0; | |
3322 | ||
bf572256 JA |
3323 | /* |
3324 | * Put the new queue at the front of the of the current list, | |
3325 | * so we know that it will be selected next. | |
3326 | */ | |
3327 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); | |
edd75ffd JA |
3328 | |
3329 | cfq_service_tree_add(cfqd, cfqq, 1); | |
eda5e0c9 | 3330 | |
62a37f6b JT |
3331 | cfqq->slice_end = 0; |
3332 | cfq_mark_cfqq_slice_new(cfqq); | |
22e2c507 JA |
3333 | } |
3334 | ||
22e2c507 | 3335 | /* |
5e705374 | 3336 | * Called when a new fs request (rq) is added (to cfqq). Check if there's |
22e2c507 JA |
3337 | * something we should do about it |
3338 | */ | |
3339 | static void | |
5e705374 JA |
3340 | cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
3341 | struct request *rq) | |
22e2c507 | 3342 | { |
5e705374 | 3343 | struct cfq_io_context *cic = RQ_CIC(rq); |
12e9fddd | 3344 | |
45333d5a | 3345 | cfqd->rq_queued++; |
7b6d91da | 3346 | if (rq->cmd_flags & REQ_META) |
374f84ac JA |
3347 | cfqq->meta_pending++; |
3348 | ||
9c2c38a1 | 3349 | cfq_update_io_thinktime(cfqd, cic); |
b2c18e1e | 3350 | cfq_update_io_seektime(cfqd, cfqq, rq); |
9c2c38a1 JA |
3351 | cfq_update_idle_window(cfqd, cfqq, cic); |
3352 | ||
b2c18e1e | 3353 | cfqq->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq); |
22e2c507 JA |
3354 | |
3355 | if (cfqq == cfqd->active_queue) { | |
3356 | /* | |
b029195d JA |
3357 | * Remember that we saw a request from this process, but |
3358 | * don't start queuing just yet. Otherwise we risk seeing lots | |
3359 | * of tiny requests, because we disrupt the normal plugging | |
d6ceb25e JA |
3360 | * and merging. If the request is already larger than a single |
3361 | * page, let it rip immediately. For that case we assume that | |
2d870722 JA |
3362 | * merging is already done. Ditto for a busy system that |
3363 | * has other work pending, don't risk delaying until the | |
3364 | * idle timer unplug to continue working. | |
22e2c507 | 3365 | */ |
d6ceb25e | 3366 | if (cfq_cfqq_wait_request(cfqq)) { |
2d870722 JA |
3367 | if (blk_rq_bytes(rq) > PAGE_CACHE_SIZE || |
3368 | cfqd->busy_queues > 1) { | |
812df48d | 3369 | cfq_del_timer(cfqd, cfqq); |
554554f6 | 3370 | cfq_clear_cfqq_wait_request(cfqq); |
1654e741 | 3371 | __blk_run_queue(cfqd->queue, false); |
a11cdaa7 | 3372 | } else { |
e98ef89b | 3373 | cfq_blkiocg_update_idle_time_stats( |
a11cdaa7 | 3374 | &cfqq->cfqg->blkg); |
bf791937 | 3375 | cfq_mark_cfqq_must_dispatch(cfqq); |
a11cdaa7 | 3376 | } |
d6ceb25e | 3377 | } |
5e705374 | 3378 | } else if (cfq_should_preempt(cfqd, cfqq, rq)) { |
22e2c507 JA |
3379 | /* |
3380 | * not the active queue - expire current slice if it is | |
3381 | * idle and has expired it's mean thinktime or this new queue | |
3a9a3f6c DS |
3382 | * has some old slice time left and is of higher priority or |
3383 | * this new queue is RT and the current one is BE | |
22e2c507 JA |
3384 | */ |
3385 | cfq_preempt_queue(cfqd, cfqq); | |
1654e741 | 3386 | __blk_run_queue(cfqd->queue, false); |
22e2c507 | 3387 | } |
1da177e4 LT |
3388 | } |
3389 | ||
165125e1 | 3390 | static void cfq_insert_request(struct request_queue *q, struct request *rq) |
1da177e4 | 3391 | { |
b4878f24 | 3392 | struct cfq_data *cfqd = q->elevator->elevator_data; |
5e705374 | 3393 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 | 3394 | |
7b679138 | 3395 | cfq_log_cfqq(cfqd, cfqq, "insert_request"); |
fd0928df | 3396 | cfq_init_prio_data(cfqq, RQ_CIC(rq)->ioc); |
1da177e4 | 3397 | |
30996f40 | 3398 | rq_set_fifo_time(rq, jiffies + cfqd->cfq_fifo_expire[rq_is_sync(rq)]); |
22e2c507 | 3399 | list_add_tail(&rq->queuelist, &cfqq->fifo); |
aa6f6a3d | 3400 | cfq_add_rq_rb(rq); |
e98ef89b | 3401 | cfq_blkiocg_update_io_add_stats(&(RQ_CFQG(rq))->blkg, |
cdc1184c DS |
3402 | &cfqd->serving_group->blkg, rq_data_dir(rq), |
3403 | rq_is_sync(rq)); | |
5e705374 | 3404 | cfq_rq_enqueued(cfqd, cfqq, rq); |
1da177e4 LT |
3405 | } |
3406 | ||
45333d5a AC |
3407 | /* |
3408 | * Update hw_tag based on peak queue depth over 50 samples under | |
3409 | * sufficient load. | |
3410 | */ | |
3411 | static void cfq_update_hw_tag(struct cfq_data *cfqd) | |
3412 | { | |
1a1238a7 SL |
3413 | struct cfq_queue *cfqq = cfqd->active_queue; |
3414 | ||
53c583d2 CZ |
3415 | if (cfqd->rq_in_driver > cfqd->hw_tag_est_depth) |
3416 | cfqd->hw_tag_est_depth = cfqd->rq_in_driver; | |
e459dd08 CZ |
3417 | |
3418 | if (cfqd->hw_tag == 1) | |
3419 | return; | |
45333d5a AC |
3420 | |
3421 | if (cfqd->rq_queued <= CFQ_HW_QUEUE_MIN && | |
53c583d2 | 3422 | cfqd->rq_in_driver <= CFQ_HW_QUEUE_MIN) |
45333d5a AC |
3423 | return; |
3424 | ||
1a1238a7 SL |
3425 | /* |
3426 | * If active queue hasn't enough requests and can idle, cfq might not | |
3427 | * dispatch sufficient requests to hardware. Don't zero hw_tag in this | |
3428 | * case | |
3429 | */ | |
3430 | if (cfqq && cfq_cfqq_idle_window(cfqq) && | |
3431 | cfqq->dispatched + cfqq->queued[0] + cfqq->queued[1] < | |
53c583d2 | 3432 | CFQ_HW_QUEUE_MIN && cfqd->rq_in_driver < CFQ_HW_QUEUE_MIN) |
1a1238a7 SL |
3433 | return; |
3434 | ||
45333d5a AC |
3435 | if (cfqd->hw_tag_samples++ < 50) |
3436 | return; | |
3437 | ||
e459dd08 | 3438 | if (cfqd->hw_tag_est_depth >= CFQ_HW_QUEUE_MIN) |
45333d5a AC |
3439 | cfqd->hw_tag = 1; |
3440 | else | |
3441 | cfqd->hw_tag = 0; | |
45333d5a AC |
3442 | } |
3443 | ||
7667aa06 VG |
3444 | static bool cfq_should_wait_busy(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
3445 | { | |
3446 | struct cfq_io_context *cic = cfqd->active_cic; | |
3447 | ||
02a8f01b JT |
3448 | /* If the queue already has requests, don't wait */ |
3449 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) | |
3450 | return false; | |
3451 | ||
7667aa06 VG |
3452 | /* If there are other queues in the group, don't wait */ |
3453 | if (cfqq->cfqg->nr_cfqq > 1) | |
3454 | return false; | |
3455 | ||
3456 | if (cfq_slice_used(cfqq)) | |
3457 | return true; | |
3458 | ||
3459 | /* if slice left is less than think time, wait busy */ | |
3460 | if (cic && sample_valid(cic->ttime_samples) | |
3461 | && (cfqq->slice_end - jiffies < cic->ttime_mean)) | |
3462 | return true; | |
3463 | ||
3464 | /* | |
3465 | * If think times is less than a jiffy than ttime_mean=0 and above | |
3466 | * will not be true. It might happen that slice has not expired yet | |
3467 | * but will expire soon (4-5 ns) during select_queue(). To cover the | |
3468 | * case where think time is less than a jiffy, mark the queue wait | |
3469 | * busy if only 1 jiffy is left in the slice. | |
3470 | */ | |
3471 | if (cfqq->slice_end - jiffies == 1) | |
3472 | return true; | |
3473 | ||
3474 | return false; | |
3475 | } | |
3476 | ||
165125e1 | 3477 | static void cfq_completed_request(struct request_queue *q, struct request *rq) |
1da177e4 | 3478 | { |
5e705374 | 3479 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
b4878f24 | 3480 | struct cfq_data *cfqd = cfqq->cfqd; |
5380a101 | 3481 | const int sync = rq_is_sync(rq); |
b4878f24 | 3482 | unsigned long now; |
1da177e4 | 3483 | |
b4878f24 | 3484 | now = jiffies; |
33659ebb CH |
3485 | cfq_log_cfqq(cfqd, cfqq, "complete rqnoidle %d", |
3486 | !!(rq->cmd_flags & REQ_NOIDLE)); | |
1da177e4 | 3487 | |
45333d5a AC |
3488 | cfq_update_hw_tag(cfqd); |
3489 | ||
53c583d2 | 3490 | WARN_ON(!cfqd->rq_in_driver); |
6d048f53 | 3491 | WARN_ON(!cfqq->dispatched); |
53c583d2 | 3492 | cfqd->rq_in_driver--; |
6d048f53 | 3493 | cfqq->dispatched--; |
80bdf0c7 | 3494 | (RQ_CFQG(rq))->dispatched--; |
e98ef89b VG |
3495 | cfq_blkiocg_update_completion_stats(&cfqq->cfqg->blkg, |
3496 | rq_start_time_ns(rq), rq_io_start_time_ns(rq), | |
3497 | rq_data_dir(rq), rq_is_sync(rq)); | |
1da177e4 | 3498 | |
53c583d2 | 3499 | cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]--; |
3ed9a296 | 3500 | |
365722bb | 3501 | if (sync) { |
5e705374 | 3502 | RQ_CIC(rq)->last_end_request = now; |
573412b2 CZ |
3503 | if (!time_after(rq->start_time + cfqd->cfq_fifo_expire[1], now)) |
3504 | cfqd->last_delayed_sync = now; | |
365722bb | 3505 | } |
caaa5f9f JA |
3506 | |
3507 | /* | |
3508 | * If this is the active queue, check if it needs to be expired, | |
3509 | * or if we want to idle in case it has no pending requests. | |
3510 | */ | |
3511 | if (cfqd->active_queue == cfqq) { | |
a36e71f9 JA |
3512 | const bool cfqq_empty = RB_EMPTY_ROOT(&cfqq->sort_list); |
3513 | ||
44f7c160 JA |
3514 | if (cfq_cfqq_slice_new(cfqq)) { |
3515 | cfq_set_prio_slice(cfqd, cfqq); | |
3516 | cfq_clear_cfqq_slice_new(cfqq); | |
3517 | } | |
f75edf2d VG |
3518 | |
3519 | /* | |
7667aa06 VG |
3520 | * Should we wait for next request to come in before we expire |
3521 | * the queue. | |
f75edf2d | 3522 | */ |
7667aa06 | 3523 | if (cfq_should_wait_busy(cfqd, cfqq)) { |
80bdf0c7 VG |
3524 | unsigned long extend_sl = cfqd->cfq_slice_idle; |
3525 | if (!cfqd->cfq_slice_idle) | |
3526 | extend_sl = cfqd->cfq_group_idle; | |
3527 | cfqq->slice_end = jiffies + extend_sl; | |
f75edf2d | 3528 | cfq_mark_cfqq_wait_busy(cfqq); |
b1ffe737 | 3529 | cfq_log_cfqq(cfqd, cfqq, "will busy wait"); |
f75edf2d VG |
3530 | } |
3531 | ||
a36e71f9 | 3532 | /* |
8e550632 CZ |
3533 | * Idling is not enabled on: |
3534 | * - expired queues | |
3535 | * - idle-priority queues | |
3536 | * - async queues | |
3537 | * - queues with still some requests queued | |
3538 | * - when there is a close cooperator | |
a36e71f9 | 3539 | */ |
0871714e | 3540 | if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq)) |
e5ff082e | 3541 | cfq_slice_expired(cfqd, 1); |
8e550632 CZ |
3542 | else if (sync && cfqq_empty && |
3543 | !cfq_close_cooperator(cfqd, cfqq)) { | |
749ef9f8 | 3544 | cfq_arm_slice_timer(cfqd); |
8e550632 | 3545 | } |
caaa5f9f | 3546 | } |
6d048f53 | 3547 | |
53c583d2 | 3548 | if (!cfqd->rq_in_driver) |
23e018a1 | 3549 | cfq_schedule_dispatch(cfqd); |
1da177e4 LT |
3550 | } |
3551 | ||
22e2c507 JA |
3552 | /* |
3553 | * we temporarily boost lower priority queues if they are holding fs exclusive | |
3554 | * resources. they are boosted to normal prio (CLASS_BE/4) | |
3555 | */ | |
3556 | static void cfq_prio_boost(struct cfq_queue *cfqq) | |
1da177e4 | 3557 | { |
22e2c507 JA |
3558 | if (has_fs_excl()) { |
3559 | /* | |
3560 | * boost idle prio on transactions that would lock out other | |
3561 | * users of the filesystem | |
3562 | */ | |
3563 | if (cfq_class_idle(cfqq)) | |
3564 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
3565 | if (cfqq->ioprio > IOPRIO_NORM) | |
3566 | cfqq->ioprio = IOPRIO_NORM; | |
3567 | } else { | |
3568 | /* | |
dddb7451 | 3569 | * unboost the queue (if needed) |
22e2c507 | 3570 | */ |
dddb7451 CZ |
3571 | cfqq->ioprio_class = cfqq->org_ioprio_class; |
3572 | cfqq->ioprio = cfqq->org_ioprio; | |
22e2c507 | 3573 | } |
22e2c507 | 3574 | } |
1da177e4 | 3575 | |
89850f7e | 3576 | static inline int __cfq_may_queue(struct cfq_queue *cfqq) |
22e2c507 | 3577 | { |
1b379d8d | 3578 | if (cfq_cfqq_wait_request(cfqq) && !cfq_cfqq_must_alloc_slice(cfqq)) { |
3b18152c | 3579 | cfq_mark_cfqq_must_alloc_slice(cfqq); |
22e2c507 | 3580 | return ELV_MQUEUE_MUST; |
3b18152c | 3581 | } |
1da177e4 | 3582 | |
22e2c507 | 3583 | return ELV_MQUEUE_MAY; |
22e2c507 JA |
3584 | } |
3585 | ||
165125e1 | 3586 | static int cfq_may_queue(struct request_queue *q, int rw) |
22e2c507 JA |
3587 | { |
3588 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
3589 | struct task_struct *tsk = current; | |
91fac317 | 3590 | struct cfq_io_context *cic; |
22e2c507 JA |
3591 | struct cfq_queue *cfqq; |
3592 | ||
3593 | /* | |
3594 | * don't force setup of a queue from here, as a call to may_queue | |
3595 | * does not necessarily imply that a request actually will be queued. | |
3596 | * so just lookup a possibly existing queue, or return 'may queue' | |
3597 | * if that fails | |
3598 | */ | |
4ac845a2 | 3599 | cic = cfq_cic_lookup(cfqd, tsk->io_context); |
91fac317 VT |
3600 | if (!cic) |
3601 | return ELV_MQUEUE_MAY; | |
3602 | ||
b0b78f81 | 3603 | cfqq = cic_to_cfqq(cic, rw_is_sync(rw)); |
22e2c507 | 3604 | if (cfqq) { |
fd0928df | 3605 | cfq_init_prio_data(cfqq, cic->ioc); |
22e2c507 JA |
3606 | cfq_prio_boost(cfqq); |
3607 | ||
89850f7e | 3608 | return __cfq_may_queue(cfqq); |
22e2c507 JA |
3609 | } |
3610 | ||
3611 | return ELV_MQUEUE_MAY; | |
1da177e4 LT |
3612 | } |
3613 | ||
1da177e4 LT |
3614 | /* |
3615 | * queue lock held here | |
3616 | */ | |
bb37b94c | 3617 | static void cfq_put_request(struct request *rq) |
1da177e4 | 3618 | { |
5e705374 | 3619 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
1da177e4 | 3620 | |
5e705374 | 3621 | if (cfqq) { |
22e2c507 | 3622 | const int rw = rq_data_dir(rq); |
1da177e4 | 3623 | |
22e2c507 JA |
3624 | BUG_ON(!cfqq->allocated[rw]); |
3625 | cfqq->allocated[rw]--; | |
1da177e4 | 3626 | |
5e705374 | 3627 | put_io_context(RQ_CIC(rq)->ioc); |
1da177e4 | 3628 | |
c186794d MS |
3629 | rq->elevator_private[0] = NULL; |
3630 | rq->elevator_private[1] = NULL; | |
1da177e4 | 3631 | |
7f1dc8a2 VG |
3632 | /* Put down rq reference on cfqg */ |
3633 | cfq_put_cfqg(RQ_CFQG(rq)); | |
c186794d | 3634 | rq->elevator_private[2] = NULL; |
7f1dc8a2 | 3635 | |
1da177e4 LT |
3636 | cfq_put_queue(cfqq); |
3637 | } | |
3638 | } | |
3639 | ||
df5fe3e8 JM |
3640 | static struct cfq_queue * |
3641 | cfq_merge_cfqqs(struct cfq_data *cfqd, struct cfq_io_context *cic, | |
3642 | struct cfq_queue *cfqq) | |
3643 | { | |
3644 | cfq_log_cfqq(cfqd, cfqq, "merging with queue %p", cfqq->new_cfqq); | |
3645 | cic_set_cfqq(cic, cfqq->new_cfqq, 1); | |
b3b6d040 | 3646 | cfq_mark_cfqq_coop(cfqq->new_cfqq); |
df5fe3e8 JM |
3647 | cfq_put_queue(cfqq); |
3648 | return cic_to_cfqq(cic, 1); | |
3649 | } | |
3650 | ||
e6c5bc73 JM |
3651 | /* |
3652 | * Returns NULL if a new cfqq should be allocated, or the old cfqq if this | |
3653 | * was the last process referring to said cfqq. | |
3654 | */ | |
3655 | static struct cfq_queue * | |
3656 | split_cfqq(struct cfq_io_context *cic, struct cfq_queue *cfqq) | |
3657 | { | |
3658 | if (cfqq_process_refs(cfqq) == 1) { | |
e6c5bc73 JM |
3659 | cfqq->pid = current->pid; |
3660 | cfq_clear_cfqq_coop(cfqq); | |
ae54abed | 3661 | cfq_clear_cfqq_split_coop(cfqq); |
e6c5bc73 JM |
3662 | return cfqq; |
3663 | } | |
3664 | ||
3665 | cic_set_cfqq(cic, NULL, 1); | |
d02a2c07 SL |
3666 | |
3667 | cfq_put_cooperator(cfqq); | |
3668 | ||
e6c5bc73 JM |
3669 | cfq_put_queue(cfqq); |
3670 | return NULL; | |
3671 | } | |
1da177e4 | 3672 | /* |
22e2c507 | 3673 | * Allocate cfq data structures associated with this request. |
1da177e4 | 3674 | */ |
22e2c507 | 3675 | static int |
165125e1 | 3676 | cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask) |
1da177e4 LT |
3677 | { |
3678 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
3679 | struct cfq_io_context *cic; | |
3680 | const int rw = rq_data_dir(rq); | |
a6151c3a | 3681 | const bool is_sync = rq_is_sync(rq); |
22e2c507 | 3682 | struct cfq_queue *cfqq; |
1da177e4 LT |
3683 | unsigned long flags; |
3684 | ||
3685 | might_sleep_if(gfp_mask & __GFP_WAIT); | |
3686 | ||
e2d74ac0 | 3687 | cic = cfq_get_io_context(cfqd, gfp_mask); |
22e2c507 | 3688 | |
1da177e4 LT |
3689 | spin_lock_irqsave(q->queue_lock, flags); |
3690 | ||
22e2c507 JA |
3691 | if (!cic) |
3692 | goto queue_fail; | |
3693 | ||
e6c5bc73 | 3694 | new_queue: |
91fac317 | 3695 | cfqq = cic_to_cfqq(cic, is_sync); |
32f2e807 | 3696 | if (!cfqq || cfqq == &cfqd->oom_cfqq) { |
fd0928df | 3697 | cfqq = cfq_get_queue(cfqd, is_sync, cic->ioc, gfp_mask); |
91fac317 | 3698 | cic_set_cfqq(cic, cfqq, is_sync); |
df5fe3e8 | 3699 | } else { |
e6c5bc73 JM |
3700 | /* |
3701 | * If the queue was seeky for too long, break it apart. | |
3702 | */ | |
ae54abed | 3703 | if (cfq_cfqq_coop(cfqq) && cfq_cfqq_split_coop(cfqq)) { |
e6c5bc73 JM |
3704 | cfq_log_cfqq(cfqd, cfqq, "breaking apart cfqq"); |
3705 | cfqq = split_cfqq(cic, cfqq); | |
3706 | if (!cfqq) | |
3707 | goto new_queue; | |
3708 | } | |
3709 | ||
df5fe3e8 JM |
3710 | /* |
3711 | * Check to see if this queue is scheduled to merge with | |
3712 | * another, closely cooperating queue. The merging of | |
3713 | * queues happens here as it must be done in process context. | |
3714 | * The reference on new_cfqq was taken in merge_cfqqs. | |
3715 | */ | |
3716 | if (cfqq->new_cfqq) | |
3717 | cfqq = cfq_merge_cfqqs(cfqd, cic, cfqq); | |
91fac317 | 3718 | } |
1da177e4 LT |
3719 | |
3720 | cfqq->allocated[rw]++; | |
1da177e4 | 3721 | |
6fae9c25 | 3722 | cfqq->ref++; |
c186794d MS |
3723 | rq->elevator_private[0] = cic; |
3724 | rq->elevator_private[1] = cfqq; | |
3725 | rq->elevator_private[2] = cfq_ref_get_cfqg(cfqq->cfqg); | |
93803e01 | 3726 | spin_unlock_irqrestore(q->queue_lock, flags); |
5e705374 | 3727 | return 0; |
1da177e4 | 3728 | |
22e2c507 JA |
3729 | queue_fail: |
3730 | if (cic) | |
3731 | put_io_context(cic->ioc); | |
89850f7e | 3732 | |
23e018a1 | 3733 | cfq_schedule_dispatch(cfqd); |
1da177e4 | 3734 | spin_unlock_irqrestore(q->queue_lock, flags); |
7b679138 | 3735 | cfq_log(cfqd, "set_request fail"); |
1da177e4 LT |
3736 | return 1; |
3737 | } | |
3738 | ||
65f27f38 | 3739 | static void cfq_kick_queue(struct work_struct *work) |
22e2c507 | 3740 | { |
65f27f38 | 3741 | struct cfq_data *cfqd = |
23e018a1 | 3742 | container_of(work, struct cfq_data, unplug_work); |
165125e1 | 3743 | struct request_queue *q = cfqd->queue; |
22e2c507 | 3744 | |
40bb54d1 | 3745 | spin_lock_irq(q->queue_lock); |
1654e741 | 3746 | __blk_run_queue(cfqd->queue, false); |
40bb54d1 | 3747 | spin_unlock_irq(q->queue_lock); |
22e2c507 JA |
3748 | } |
3749 | ||
3750 | /* | |
3751 | * Timer running if the active_queue is currently idling inside its time slice | |
3752 | */ | |
3753 | static void cfq_idle_slice_timer(unsigned long data) | |
3754 | { | |
3755 | struct cfq_data *cfqd = (struct cfq_data *) data; | |
3756 | struct cfq_queue *cfqq; | |
3757 | unsigned long flags; | |
3c6bd2f8 | 3758 | int timed_out = 1; |
22e2c507 | 3759 | |
7b679138 JA |
3760 | cfq_log(cfqd, "idle timer fired"); |
3761 | ||
22e2c507 JA |
3762 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); |
3763 | ||
fe094d98 JA |
3764 | cfqq = cfqd->active_queue; |
3765 | if (cfqq) { | |
3c6bd2f8 JA |
3766 | timed_out = 0; |
3767 | ||
b029195d JA |
3768 | /* |
3769 | * We saw a request before the queue expired, let it through | |
3770 | */ | |
3771 | if (cfq_cfqq_must_dispatch(cfqq)) | |
3772 | goto out_kick; | |
3773 | ||
22e2c507 JA |
3774 | /* |
3775 | * expired | |
3776 | */ | |
44f7c160 | 3777 | if (cfq_slice_used(cfqq)) |
22e2c507 JA |
3778 | goto expire; |
3779 | ||
3780 | /* | |
3781 | * only expire and reinvoke request handler, if there are | |
3782 | * other queues with pending requests | |
3783 | */ | |
caaa5f9f | 3784 | if (!cfqd->busy_queues) |
22e2c507 | 3785 | goto out_cont; |
22e2c507 JA |
3786 | |
3787 | /* | |
3788 | * not expired and it has a request pending, let it dispatch | |
3789 | */ | |
75e50984 | 3790 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
22e2c507 | 3791 | goto out_kick; |
76280aff CZ |
3792 | |
3793 | /* | |
3794 | * Queue depth flag is reset only when the idle didn't succeed | |
3795 | */ | |
3796 | cfq_clear_cfqq_deep(cfqq); | |
22e2c507 JA |
3797 | } |
3798 | expire: | |
e5ff082e | 3799 | cfq_slice_expired(cfqd, timed_out); |
22e2c507 | 3800 | out_kick: |
23e018a1 | 3801 | cfq_schedule_dispatch(cfqd); |
22e2c507 JA |
3802 | out_cont: |
3803 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
3804 | } | |
3805 | ||
3b18152c JA |
3806 | static void cfq_shutdown_timer_wq(struct cfq_data *cfqd) |
3807 | { | |
3808 | del_timer_sync(&cfqd->idle_slice_timer); | |
23e018a1 | 3809 | cancel_work_sync(&cfqd->unplug_work); |
3b18152c | 3810 | } |
22e2c507 | 3811 | |
c2dea2d1 VT |
3812 | static void cfq_put_async_queues(struct cfq_data *cfqd) |
3813 | { | |
3814 | int i; | |
3815 | ||
3816 | for (i = 0; i < IOPRIO_BE_NR; i++) { | |
3817 | if (cfqd->async_cfqq[0][i]) | |
3818 | cfq_put_queue(cfqd->async_cfqq[0][i]); | |
3819 | if (cfqd->async_cfqq[1][i]) | |
3820 | cfq_put_queue(cfqd->async_cfqq[1][i]); | |
c2dea2d1 | 3821 | } |
2389d1ef ON |
3822 | |
3823 | if (cfqd->async_idle_cfqq) | |
3824 | cfq_put_queue(cfqd->async_idle_cfqq); | |
c2dea2d1 VT |
3825 | } |
3826 | ||
bb729bc9 JA |
3827 | static void cfq_cfqd_free(struct rcu_head *head) |
3828 | { | |
3829 | kfree(container_of(head, struct cfq_data, rcu)); | |
3830 | } | |
3831 | ||
b374d18a | 3832 | static void cfq_exit_queue(struct elevator_queue *e) |
1da177e4 | 3833 | { |
22e2c507 | 3834 | struct cfq_data *cfqd = e->elevator_data; |
165125e1 | 3835 | struct request_queue *q = cfqd->queue; |
22e2c507 | 3836 | |
3b18152c | 3837 | cfq_shutdown_timer_wq(cfqd); |
e2d74ac0 | 3838 | |
d9ff4187 | 3839 | spin_lock_irq(q->queue_lock); |
e2d74ac0 | 3840 | |
d9ff4187 | 3841 | if (cfqd->active_queue) |
e5ff082e | 3842 | __cfq_slice_expired(cfqd, cfqd->active_queue, 0); |
e2d74ac0 JA |
3843 | |
3844 | while (!list_empty(&cfqd->cic_list)) { | |
d9ff4187 AV |
3845 | struct cfq_io_context *cic = list_entry(cfqd->cic_list.next, |
3846 | struct cfq_io_context, | |
3847 | queue_list); | |
89850f7e JA |
3848 | |
3849 | __cfq_exit_single_io_context(cfqd, cic); | |
d9ff4187 | 3850 | } |
e2d74ac0 | 3851 | |
c2dea2d1 | 3852 | cfq_put_async_queues(cfqd); |
b1c35769 | 3853 | cfq_release_cfq_groups(cfqd); |
e98ef89b | 3854 | cfq_blkiocg_del_blkio_group(&cfqd->root_group.blkg); |
15c31be4 | 3855 | |
d9ff4187 | 3856 | spin_unlock_irq(q->queue_lock); |
a90d742e AV |
3857 | |
3858 | cfq_shutdown_timer_wq(cfqd); | |
3859 | ||
80b15c73 KK |
3860 | spin_lock(&cic_index_lock); |
3861 | ida_remove(&cic_index_ida, cfqd->cic_index); | |
3862 | spin_unlock(&cic_index_lock); | |
3863 | ||
b1c35769 | 3864 | /* Wait for cfqg->blkg->key accessors to exit their grace periods. */ |
bb729bc9 | 3865 | call_rcu(&cfqd->rcu, cfq_cfqd_free); |
1da177e4 LT |
3866 | } |
3867 | ||
80b15c73 KK |
3868 | static int cfq_alloc_cic_index(void) |
3869 | { | |
3870 | int index, error; | |
3871 | ||
3872 | do { | |
3873 | if (!ida_pre_get(&cic_index_ida, GFP_KERNEL)) | |
3874 | return -ENOMEM; | |
3875 | ||
3876 | spin_lock(&cic_index_lock); | |
3877 | error = ida_get_new(&cic_index_ida, &index); | |
3878 | spin_unlock(&cic_index_lock); | |
3879 | if (error && error != -EAGAIN) | |
3880 | return error; | |
3881 | } while (error); | |
3882 | ||
3883 | return index; | |
3884 | } | |
3885 | ||
165125e1 | 3886 | static void *cfq_init_queue(struct request_queue *q) |
1da177e4 LT |
3887 | { |
3888 | struct cfq_data *cfqd; | |
718eee05 | 3889 | int i, j; |
cdb16e8f | 3890 | struct cfq_group *cfqg; |
615f0259 | 3891 | struct cfq_rb_root *st; |
1da177e4 | 3892 | |
80b15c73 KK |
3893 | i = cfq_alloc_cic_index(); |
3894 | if (i < 0) | |
3895 | return NULL; | |
3896 | ||
94f6030c | 3897 | cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL | __GFP_ZERO, q->node); |
1da177e4 | 3898 | if (!cfqd) |
bc1c1169 | 3899 | return NULL; |
1da177e4 | 3900 | |
30d7b944 SL |
3901 | /* |
3902 | * Don't need take queue_lock in the routine, since we are | |
3903 | * initializing the ioscheduler, and nobody is using cfqd | |
3904 | */ | |
80b15c73 KK |
3905 | cfqd->cic_index = i; |
3906 | ||
1fa8f6d6 VG |
3907 | /* Init root service tree */ |
3908 | cfqd->grp_service_tree = CFQ_RB_ROOT; | |
3909 | ||
cdb16e8f VG |
3910 | /* Init root group */ |
3911 | cfqg = &cfqd->root_group; | |
615f0259 VG |
3912 | for_each_cfqg_st(cfqg, i, j, st) |
3913 | *st = CFQ_RB_ROOT; | |
1fa8f6d6 | 3914 | RB_CLEAR_NODE(&cfqg->rb_node); |
26a2ac00 | 3915 | |
25bc6b07 VG |
3916 | /* Give preference to root group over other groups */ |
3917 | cfqg->weight = 2*BLKIO_WEIGHT_DEFAULT; | |
3918 | ||
25fb5169 | 3919 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
b1c35769 VG |
3920 | /* |
3921 | * Take a reference to root group which we never drop. This is just | |
3922 | * to make sure that cfq_put_cfqg() does not try to kfree root group | |
3923 | */ | |
329a6781 | 3924 | cfqg->ref = 1; |
dcf097b2 | 3925 | rcu_read_lock(); |
e98ef89b VG |
3926 | cfq_blkiocg_add_blkio_group(&blkio_root_cgroup, &cfqg->blkg, |
3927 | (void *)cfqd, 0); | |
dcf097b2 | 3928 | rcu_read_unlock(); |
25fb5169 | 3929 | #endif |
26a2ac00 JA |
3930 | /* |
3931 | * Not strictly needed (since RB_ROOT just clears the node and we | |
3932 | * zeroed cfqd on alloc), but better be safe in case someone decides | |
3933 | * to add magic to the rb code | |
3934 | */ | |
3935 | for (i = 0; i < CFQ_PRIO_LISTS; i++) | |
3936 | cfqd->prio_trees[i] = RB_ROOT; | |
3937 | ||
6118b70b JA |
3938 | /* |
3939 | * Our fallback cfqq if cfq_find_alloc_queue() runs into OOM issues. | |
3940 | * Grab a permanent reference to it, so that the normal code flow | |
3941 | * will not attempt to free it. | |
3942 | */ | |
3943 | cfq_init_cfqq(cfqd, &cfqd->oom_cfqq, 1, 0); | |
30d7b944 | 3944 | cfqd->oom_cfqq.ref++; |
cdb16e8f | 3945 | cfq_link_cfqq_cfqg(&cfqd->oom_cfqq, &cfqd->root_group); |
6118b70b | 3946 | |
d9ff4187 | 3947 | INIT_LIST_HEAD(&cfqd->cic_list); |
1da177e4 | 3948 | |
1da177e4 | 3949 | cfqd->queue = q; |
1da177e4 | 3950 | |
22e2c507 JA |
3951 | init_timer(&cfqd->idle_slice_timer); |
3952 | cfqd->idle_slice_timer.function = cfq_idle_slice_timer; | |
3953 | cfqd->idle_slice_timer.data = (unsigned long) cfqd; | |
3954 | ||
23e018a1 | 3955 | INIT_WORK(&cfqd->unplug_work, cfq_kick_queue); |
22e2c507 | 3956 | |
1da177e4 | 3957 | cfqd->cfq_quantum = cfq_quantum; |
22e2c507 JA |
3958 | cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; |
3959 | cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; | |
1da177e4 LT |
3960 | cfqd->cfq_back_max = cfq_back_max; |
3961 | cfqd->cfq_back_penalty = cfq_back_penalty; | |
22e2c507 JA |
3962 | cfqd->cfq_slice[0] = cfq_slice_async; |
3963 | cfqd->cfq_slice[1] = cfq_slice_sync; | |
3964 | cfqd->cfq_slice_async_rq = cfq_slice_async_rq; | |
3965 | cfqd->cfq_slice_idle = cfq_slice_idle; | |
80bdf0c7 | 3966 | cfqd->cfq_group_idle = cfq_group_idle; |
963b72fc | 3967 | cfqd->cfq_latency = 1; |
e459dd08 | 3968 | cfqd->hw_tag = -1; |
edc71131 CZ |
3969 | /* |
3970 | * we optimistically start assuming sync ops weren't delayed in last | |
3971 | * second, in order to have larger depth for async operations. | |
3972 | */ | |
573412b2 | 3973 | cfqd->last_delayed_sync = jiffies - HZ; |
bc1c1169 | 3974 | return cfqd; |
1da177e4 LT |
3975 | } |
3976 | ||
3977 | static void cfq_slab_kill(void) | |
3978 | { | |
d6de8be7 JA |
3979 | /* |
3980 | * Caller already ensured that pending RCU callbacks are completed, | |
3981 | * so we should have no busy allocations at this point. | |
3982 | */ | |
1da177e4 LT |
3983 | if (cfq_pool) |
3984 | kmem_cache_destroy(cfq_pool); | |
3985 | if (cfq_ioc_pool) | |
3986 | kmem_cache_destroy(cfq_ioc_pool); | |
3987 | } | |
3988 | ||
3989 | static int __init cfq_slab_setup(void) | |
3990 | { | |
0a31bd5f | 3991 | cfq_pool = KMEM_CACHE(cfq_queue, 0); |
1da177e4 LT |
3992 | if (!cfq_pool) |
3993 | goto fail; | |
3994 | ||
34e6bbf2 | 3995 | cfq_ioc_pool = KMEM_CACHE(cfq_io_context, 0); |
1da177e4 LT |
3996 | if (!cfq_ioc_pool) |
3997 | goto fail; | |
3998 | ||
3999 | return 0; | |
4000 | fail: | |
4001 | cfq_slab_kill(); | |
4002 | return -ENOMEM; | |
4003 | } | |
4004 | ||
1da177e4 LT |
4005 | /* |
4006 | * sysfs parts below --> | |
4007 | */ | |
1da177e4 LT |
4008 | static ssize_t |
4009 | cfq_var_show(unsigned int var, char *page) | |
4010 | { | |
4011 | return sprintf(page, "%d\n", var); | |
4012 | } | |
4013 | ||
4014 | static ssize_t | |
4015 | cfq_var_store(unsigned int *var, const char *page, size_t count) | |
4016 | { | |
4017 | char *p = (char *) page; | |
4018 | ||
4019 | *var = simple_strtoul(p, &p, 10); | |
4020 | return count; | |
4021 | } | |
4022 | ||
1da177e4 | 4023 | #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ |
b374d18a | 4024 | static ssize_t __FUNC(struct elevator_queue *e, char *page) \ |
1da177e4 | 4025 | { \ |
3d1ab40f | 4026 | struct cfq_data *cfqd = e->elevator_data; \ |
1da177e4 LT |
4027 | unsigned int __data = __VAR; \ |
4028 | if (__CONV) \ | |
4029 | __data = jiffies_to_msecs(__data); \ | |
4030 | return cfq_var_show(__data, (page)); \ | |
4031 | } | |
4032 | SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); | |
22e2c507 JA |
4033 | SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1); |
4034 | SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1); | |
e572ec7e AV |
4035 | SHOW_FUNCTION(cfq_back_seek_max_show, cfqd->cfq_back_max, 0); |
4036 | SHOW_FUNCTION(cfq_back_seek_penalty_show, cfqd->cfq_back_penalty, 0); | |
22e2c507 | 4037 | SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1); |
80bdf0c7 | 4038 | SHOW_FUNCTION(cfq_group_idle_show, cfqd->cfq_group_idle, 1); |
22e2c507 JA |
4039 | SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1); |
4040 | SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1); | |
4041 | SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0); | |
963b72fc | 4042 | SHOW_FUNCTION(cfq_low_latency_show, cfqd->cfq_latency, 0); |
1da177e4 LT |
4043 | #undef SHOW_FUNCTION |
4044 | ||
4045 | #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ | |
b374d18a | 4046 | static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \ |
1da177e4 | 4047 | { \ |
3d1ab40f | 4048 | struct cfq_data *cfqd = e->elevator_data; \ |
1da177e4 LT |
4049 | unsigned int __data; \ |
4050 | int ret = cfq_var_store(&__data, (page), count); \ | |
4051 | if (__data < (MIN)) \ | |
4052 | __data = (MIN); \ | |
4053 | else if (__data > (MAX)) \ | |
4054 | __data = (MAX); \ | |
4055 | if (__CONV) \ | |
4056 | *(__PTR) = msecs_to_jiffies(__data); \ | |
4057 | else \ | |
4058 | *(__PTR) = __data; \ | |
4059 | return ret; \ | |
4060 | } | |
4061 | STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); | |
fe094d98 JA |
4062 | STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, |
4063 | UINT_MAX, 1); | |
4064 | STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, | |
4065 | UINT_MAX, 1); | |
e572ec7e | 4066 | STORE_FUNCTION(cfq_back_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); |
fe094d98 JA |
4067 | STORE_FUNCTION(cfq_back_seek_penalty_store, &cfqd->cfq_back_penalty, 1, |
4068 | UINT_MAX, 0); | |
22e2c507 | 4069 | STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1); |
80bdf0c7 | 4070 | STORE_FUNCTION(cfq_group_idle_store, &cfqd->cfq_group_idle, 0, UINT_MAX, 1); |
22e2c507 JA |
4071 | STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1); |
4072 | STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1); | |
fe094d98 JA |
4073 | STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, |
4074 | UINT_MAX, 0); | |
963b72fc | 4075 | STORE_FUNCTION(cfq_low_latency_store, &cfqd->cfq_latency, 0, 1, 0); |
1da177e4 LT |
4076 | #undef STORE_FUNCTION |
4077 | ||
e572ec7e AV |
4078 | #define CFQ_ATTR(name) \ |
4079 | __ATTR(name, S_IRUGO|S_IWUSR, cfq_##name##_show, cfq_##name##_store) | |
4080 | ||
4081 | static struct elv_fs_entry cfq_attrs[] = { | |
4082 | CFQ_ATTR(quantum), | |
e572ec7e AV |
4083 | CFQ_ATTR(fifo_expire_sync), |
4084 | CFQ_ATTR(fifo_expire_async), | |
4085 | CFQ_ATTR(back_seek_max), | |
4086 | CFQ_ATTR(back_seek_penalty), | |
4087 | CFQ_ATTR(slice_sync), | |
4088 | CFQ_ATTR(slice_async), | |
4089 | CFQ_ATTR(slice_async_rq), | |
4090 | CFQ_ATTR(slice_idle), | |
80bdf0c7 | 4091 | CFQ_ATTR(group_idle), |
963b72fc | 4092 | CFQ_ATTR(low_latency), |
e572ec7e | 4093 | __ATTR_NULL |
1da177e4 LT |
4094 | }; |
4095 | ||
1da177e4 LT |
4096 | static struct elevator_type iosched_cfq = { |
4097 | .ops = { | |
4098 | .elevator_merge_fn = cfq_merge, | |
4099 | .elevator_merged_fn = cfq_merged_request, | |
4100 | .elevator_merge_req_fn = cfq_merged_requests, | |
da775265 | 4101 | .elevator_allow_merge_fn = cfq_allow_merge, |
812d4026 | 4102 | .elevator_bio_merged_fn = cfq_bio_merged, |
b4878f24 | 4103 | .elevator_dispatch_fn = cfq_dispatch_requests, |
1da177e4 | 4104 | .elevator_add_req_fn = cfq_insert_request, |
b4878f24 | 4105 | .elevator_activate_req_fn = cfq_activate_request, |
1da177e4 | 4106 | .elevator_deactivate_req_fn = cfq_deactivate_request, |
1da177e4 | 4107 | .elevator_completed_req_fn = cfq_completed_request, |
21183b07 JA |
4108 | .elevator_former_req_fn = elv_rb_former_request, |
4109 | .elevator_latter_req_fn = elv_rb_latter_request, | |
1da177e4 LT |
4110 | .elevator_set_req_fn = cfq_set_request, |
4111 | .elevator_put_req_fn = cfq_put_request, | |
4112 | .elevator_may_queue_fn = cfq_may_queue, | |
4113 | .elevator_init_fn = cfq_init_queue, | |
4114 | .elevator_exit_fn = cfq_exit_queue, | |
fc46379d | 4115 | .trim = cfq_free_io_context, |
1da177e4 | 4116 | }, |
3d1ab40f | 4117 | .elevator_attrs = cfq_attrs, |
1da177e4 LT |
4118 | .elevator_name = "cfq", |
4119 | .elevator_owner = THIS_MODULE, | |
4120 | }; | |
4121 | ||
3e252066 VG |
4122 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
4123 | static struct blkio_policy_type blkio_policy_cfq = { | |
4124 | .ops = { | |
4125 | .blkio_unlink_group_fn = cfq_unlink_blkio_group, | |
4126 | .blkio_update_group_weight_fn = cfq_update_blkio_group_weight, | |
4127 | }, | |
062a644d | 4128 | .plid = BLKIO_POLICY_PROP, |
3e252066 VG |
4129 | }; |
4130 | #else | |
4131 | static struct blkio_policy_type blkio_policy_cfq; | |
4132 | #endif | |
4133 | ||
1da177e4 LT |
4134 | static int __init cfq_init(void) |
4135 | { | |
22e2c507 JA |
4136 | /* |
4137 | * could be 0 on HZ < 1000 setups | |
4138 | */ | |
4139 | if (!cfq_slice_async) | |
4140 | cfq_slice_async = 1; | |
4141 | if (!cfq_slice_idle) | |
4142 | cfq_slice_idle = 1; | |
4143 | ||
80bdf0c7 VG |
4144 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
4145 | if (!cfq_group_idle) | |
4146 | cfq_group_idle = 1; | |
4147 | #else | |
4148 | cfq_group_idle = 0; | |
4149 | #endif | |
1da177e4 LT |
4150 | if (cfq_slab_setup()) |
4151 | return -ENOMEM; | |
4152 | ||
2fdd82bd | 4153 | elv_register(&iosched_cfq); |
3e252066 | 4154 | blkio_policy_register(&blkio_policy_cfq); |
1da177e4 | 4155 | |
2fdd82bd | 4156 | return 0; |
1da177e4 LT |
4157 | } |
4158 | ||
4159 | static void __exit cfq_exit(void) | |
4160 | { | |
6e9a4738 | 4161 | DECLARE_COMPLETION_ONSTACK(all_gone); |
3e252066 | 4162 | blkio_policy_unregister(&blkio_policy_cfq); |
1da177e4 | 4163 | elv_unregister(&iosched_cfq); |
334e94de | 4164 | ioc_gone = &all_gone; |
fba82272 OH |
4165 | /* ioc_gone's update must be visible before reading ioc_count */ |
4166 | smp_wmb(); | |
d6de8be7 JA |
4167 | |
4168 | /* | |
4169 | * this also protects us from entering cfq_slab_kill() with | |
4170 | * pending RCU callbacks | |
4171 | */ | |
245b2e70 | 4172 | if (elv_ioc_count_read(cfq_ioc_count)) |
9a11b4ed | 4173 | wait_for_completion(&all_gone); |
80b15c73 | 4174 | ida_destroy(&cic_index_ida); |
83521d3e | 4175 | cfq_slab_kill(); |
1da177e4 LT |
4176 | } |
4177 | ||
4178 | module_init(cfq_init); | |
4179 | module_exit(cfq_exit); | |
4180 | ||
4181 | MODULE_AUTHOR("Jens Axboe"); | |
4182 | MODULE_LICENSE("GPL"); | |
4183 | MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler"); |