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; | |
56edf7d7 VG |
303 | |
304 | /* Number of groups which are on blkcg->blkg_list */ | |
305 | unsigned int nr_blkcg_linked_grps; | |
1da177e4 LT |
306 | }; |
307 | ||
25fb5169 VG |
308 | static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd); |
309 | ||
cdb16e8f VG |
310 | static struct cfq_rb_root *service_tree_for(struct cfq_group *cfqg, |
311 | enum wl_prio_t prio, | |
65b32a57 | 312 | enum wl_type_t type) |
c0324a02 | 313 | { |
1fa8f6d6 VG |
314 | if (!cfqg) |
315 | return NULL; | |
316 | ||
c0324a02 | 317 | if (prio == IDLE_WORKLOAD) |
cdb16e8f | 318 | return &cfqg->service_tree_idle; |
c0324a02 | 319 | |
cdb16e8f | 320 | return &cfqg->service_trees[prio][type]; |
c0324a02 CZ |
321 | } |
322 | ||
3b18152c | 323 | enum cfqq_state_flags { |
b0b8d749 JA |
324 | CFQ_CFQQ_FLAG_on_rr = 0, /* on round-robin busy list */ |
325 | CFQ_CFQQ_FLAG_wait_request, /* waiting for a request */ | |
b029195d | 326 | CFQ_CFQQ_FLAG_must_dispatch, /* must be allowed a dispatch */ |
b0b8d749 | 327 | CFQ_CFQQ_FLAG_must_alloc_slice, /* per-slice must_alloc flag */ |
b0b8d749 JA |
328 | CFQ_CFQQ_FLAG_fifo_expire, /* FIFO checked in this slice */ |
329 | CFQ_CFQQ_FLAG_idle_window, /* slice idling enabled */ | |
330 | CFQ_CFQQ_FLAG_prio_changed, /* task priority has changed */ | |
44f7c160 | 331 | CFQ_CFQQ_FLAG_slice_new, /* no requests dispatched in slice */ |
91fac317 | 332 | CFQ_CFQQ_FLAG_sync, /* synchronous queue */ |
b3b6d040 | 333 | CFQ_CFQQ_FLAG_coop, /* cfqq is shared */ |
ae54abed | 334 | CFQ_CFQQ_FLAG_split_coop, /* shared cfqq will be splitted */ |
76280aff | 335 | CFQ_CFQQ_FLAG_deep, /* sync cfqq experienced large depth */ |
f75edf2d | 336 | CFQ_CFQQ_FLAG_wait_busy, /* Waiting for next request */ |
3b18152c JA |
337 | }; |
338 | ||
339 | #define CFQ_CFQQ_FNS(name) \ | |
340 | static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \ | |
341 | { \ | |
fe094d98 | 342 | (cfqq)->flags |= (1 << CFQ_CFQQ_FLAG_##name); \ |
3b18152c JA |
343 | } \ |
344 | static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \ | |
345 | { \ | |
fe094d98 | 346 | (cfqq)->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \ |
3b18152c JA |
347 | } \ |
348 | static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \ | |
349 | { \ | |
fe094d98 | 350 | return ((cfqq)->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \ |
3b18152c JA |
351 | } |
352 | ||
353 | CFQ_CFQQ_FNS(on_rr); | |
354 | CFQ_CFQQ_FNS(wait_request); | |
b029195d | 355 | CFQ_CFQQ_FNS(must_dispatch); |
3b18152c | 356 | CFQ_CFQQ_FNS(must_alloc_slice); |
3b18152c JA |
357 | CFQ_CFQQ_FNS(fifo_expire); |
358 | CFQ_CFQQ_FNS(idle_window); | |
359 | CFQ_CFQQ_FNS(prio_changed); | |
44f7c160 | 360 | CFQ_CFQQ_FNS(slice_new); |
91fac317 | 361 | CFQ_CFQQ_FNS(sync); |
a36e71f9 | 362 | CFQ_CFQQ_FNS(coop); |
ae54abed | 363 | CFQ_CFQQ_FNS(split_coop); |
76280aff | 364 | CFQ_CFQQ_FNS(deep); |
f75edf2d | 365 | CFQ_CFQQ_FNS(wait_busy); |
3b18152c JA |
366 | #undef CFQ_CFQQ_FNS |
367 | ||
afc24d49 | 368 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
2868ef7b VG |
369 | #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \ |
370 | blk_add_trace_msg((cfqd)->queue, "cfq%d%c %s " fmt, (cfqq)->pid, \ | |
371 | cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \ | |
372 | blkg_path(&(cfqq)->cfqg->blkg), ##args); | |
373 | ||
374 | #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) \ | |
375 | blk_add_trace_msg((cfqd)->queue, "%s " fmt, \ | |
376 | blkg_path(&(cfqg)->blkg), ##args); \ | |
377 | ||
378 | #else | |
7b679138 JA |
379 | #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \ |
380 | blk_add_trace_msg((cfqd)->queue, "cfq%d " fmt, (cfqq)->pid, ##args) | |
2868ef7b VG |
381 | #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) do {} while (0); |
382 | #endif | |
7b679138 JA |
383 | #define cfq_log(cfqd, fmt, args...) \ |
384 | blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args) | |
385 | ||
615f0259 VG |
386 | /* Traverses through cfq group service trees */ |
387 | #define for_each_cfqg_st(cfqg, i, j, st) \ | |
388 | for (i = 0; i <= IDLE_WORKLOAD; i++) \ | |
389 | for (j = 0, st = i < IDLE_WORKLOAD ? &cfqg->service_trees[i][j]\ | |
390 | : &cfqg->service_tree_idle; \ | |
391 | (i < IDLE_WORKLOAD && j <= SYNC_WORKLOAD) || \ | |
392 | (i == IDLE_WORKLOAD && j == 0); \ | |
393 | j++, st = i < IDLE_WORKLOAD ? \ | |
394 | &cfqg->service_trees[i][j]: NULL) \ | |
395 | ||
396 | ||
02b35081 VG |
397 | static inline bool iops_mode(struct cfq_data *cfqd) |
398 | { | |
399 | /* | |
400 | * If we are not idling on queues and it is a NCQ drive, parallel | |
401 | * execution of requests is on and measuring time is not possible | |
402 | * in most of the cases until and unless we drive shallower queue | |
403 | * depths and that becomes a performance bottleneck. In such cases | |
404 | * switch to start providing fairness in terms of number of IOs. | |
405 | */ | |
406 | if (!cfqd->cfq_slice_idle && cfqd->hw_tag) | |
407 | return true; | |
408 | else | |
409 | return false; | |
410 | } | |
411 | ||
c0324a02 CZ |
412 | static inline enum wl_prio_t cfqq_prio(struct cfq_queue *cfqq) |
413 | { | |
414 | if (cfq_class_idle(cfqq)) | |
415 | return IDLE_WORKLOAD; | |
416 | if (cfq_class_rt(cfqq)) | |
417 | return RT_WORKLOAD; | |
418 | return BE_WORKLOAD; | |
419 | } | |
420 | ||
718eee05 CZ |
421 | |
422 | static enum wl_type_t cfqq_type(struct cfq_queue *cfqq) | |
423 | { | |
424 | if (!cfq_cfqq_sync(cfqq)) | |
425 | return ASYNC_WORKLOAD; | |
426 | if (!cfq_cfqq_idle_window(cfqq)) | |
427 | return SYNC_NOIDLE_WORKLOAD; | |
428 | return SYNC_WORKLOAD; | |
429 | } | |
430 | ||
58ff82f3 VG |
431 | static inline int cfq_group_busy_queues_wl(enum wl_prio_t wl, |
432 | struct cfq_data *cfqd, | |
433 | struct cfq_group *cfqg) | |
c0324a02 CZ |
434 | { |
435 | if (wl == IDLE_WORKLOAD) | |
cdb16e8f | 436 | return cfqg->service_tree_idle.count; |
c0324a02 | 437 | |
cdb16e8f VG |
438 | return cfqg->service_trees[wl][ASYNC_WORKLOAD].count |
439 | + cfqg->service_trees[wl][SYNC_NOIDLE_WORKLOAD].count | |
440 | + cfqg->service_trees[wl][SYNC_WORKLOAD].count; | |
c0324a02 CZ |
441 | } |
442 | ||
f26bd1f0 VG |
443 | static inline int cfqg_busy_async_queues(struct cfq_data *cfqd, |
444 | struct cfq_group *cfqg) | |
445 | { | |
446 | return cfqg->service_trees[RT_WORKLOAD][ASYNC_WORKLOAD].count | |
447 | + cfqg->service_trees[BE_WORKLOAD][ASYNC_WORKLOAD].count; | |
448 | } | |
449 | ||
165125e1 | 450 | static void cfq_dispatch_insert(struct request_queue *, struct request *); |
a6151c3a | 451 | static struct cfq_queue *cfq_get_queue(struct cfq_data *, bool, |
fd0928df | 452 | struct io_context *, gfp_t); |
4ac845a2 | 453 | static struct cfq_io_context *cfq_cic_lookup(struct cfq_data *, |
91fac317 VT |
454 | struct io_context *); |
455 | ||
456 | static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_context *cic, | |
a6151c3a | 457 | bool is_sync) |
91fac317 | 458 | { |
a6151c3a | 459 | return cic->cfqq[is_sync]; |
91fac317 VT |
460 | } |
461 | ||
462 | static inline void cic_set_cfqq(struct cfq_io_context *cic, | |
a6151c3a | 463 | struct cfq_queue *cfqq, bool is_sync) |
91fac317 | 464 | { |
a6151c3a | 465 | cic->cfqq[is_sync] = cfqq; |
91fac317 VT |
466 | } |
467 | ||
bca4b914 | 468 | #define CIC_DEAD_KEY 1ul |
80b15c73 | 469 | #define CIC_DEAD_INDEX_SHIFT 1 |
bca4b914 KK |
470 | |
471 | static inline void *cfqd_dead_key(struct cfq_data *cfqd) | |
472 | { | |
80b15c73 | 473 | return (void *)(cfqd->cic_index << CIC_DEAD_INDEX_SHIFT | CIC_DEAD_KEY); |
bca4b914 KK |
474 | } |
475 | ||
476 | static inline struct cfq_data *cic_to_cfqd(struct cfq_io_context *cic) | |
477 | { | |
478 | struct cfq_data *cfqd = cic->key; | |
479 | ||
480 | if (unlikely((unsigned long) cfqd & CIC_DEAD_KEY)) | |
481 | return NULL; | |
482 | ||
483 | return cfqd; | |
484 | } | |
485 | ||
91fac317 VT |
486 | /* |
487 | * We regard a request as SYNC, if it's either a read or has the SYNC bit | |
488 | * set (in which case it could also be direct WRITE). | |
489 | */ | |
a6151c3a | 490 | static inline bool cfq_bio_sync(struct bio *bio) |
91fac317 | 491 | { |
7b6d91da | 492 | return bio_data_dir(bio) == READ || (bio->bi_rw & REQ_SYNC); |
91fac317 | 493 | } |
1da177e4 | 494 | |
99f95e52 AM |
495 | /* |
496 | * scheduler run of queue, if there are requests pending and no one in the | |
497 | * driver that will restart queueing | |
498 | */ | |
23e018a1 | 499 | static inline void cfq_schedule_dispatch(struct cfq_data *cfqd) |
99f95e52 | 500 | { |
7b679138 JA |
501 | if (cfqd->busy_queues) { |
502 | cfq_log(cfqd, "schedule dispatch"); | |
23e018a1 | 503 | kblockd_schedule_work(cfqd->queue, &cfqd->unplug_work); |
7b679138 | 504 | } |
99f95e52 AM |
505 | } |
506 | ||
44f7c160 JA |
507 | /* |
508 | * Scale schedule slice based on io priority. Use the sync time slice only | |
509 | * if a queue is marked sync and has sync io queued. A sync queue with async | |
510 | * io only, should not get full sync slice length. | |
511 | */ | |
a6151c3a | 512 | static inline int cfq_prio_slice(struct cfq_data *cfqd, bool sync, |
d9e7620e | 513 | unsigned short prio) |
44f7c160 | 514 | { |
d9e7620e | 515 | const int base_slice = cfqd->cfq_slice[sync]; |
44f7c160 | 516 | |
d9e7620e JA |
517 | WARN_ON(prio >= IOPRIO_BE_NR); |
518 | ||
519 | return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - prio)); | |
520 | } | |
44f7c160 | 521 | |
d9e7620e JA |
522 | static inline int |
523 | cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
524 | { | |
525 | return cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio); | |
44f7c160 JA |
526 | } |
527 | ||
25bc6b07 VG |
528 | static inline u64 cfq_scale_slice(unsigned long delta, struct cfq_group *cfqg) |
529 | { | |
530 | u64 d = delta << CFQ_SERVICE_SHIFT; | |
531 | ||
532 | d = d * BLKIO_WEIGHT_DEFAULT; | |
533 | do_div(d, cfqg->weight); | |
534 | return d; | |
535 | } | |
536 | ||
537 | static inline u64 max_vdisktime(u64 min_vdisktime, u64 vdisktime) | |
538 | { | |
539 | s64 delta = (s64)(vdisktime - min_vdisktime); | |
540 | if (delta > 0) | |
541 | min_vdisktime = vdisktime; | |
542 | ||
543 | return min_vdisktime; | |
544 | } | |
545 | ||
546 | static inline u64 min_vdisktime(u64 min_vdisktime, u64 vdisktime) | |
547 | { | |
548 | s64 delta = (s64)(vdisktime - min_vdisktime); | |
549 | if (delta < 0) | |
550 | min_vdisktime = vdisktime; | |
551 | ||
552 | return min_vdisktime; | |
553 | } | |
554 | ||
555 | static void update_min_vdisktime(struct cfq_rb_root *st) | |
556 | { | |
25bc6b07 VG |
557 | struct cfq_group *cfqg; |
558 | ||
25bc6b07 VG |
559 | if (st->left) { |
560 | cfqg = rb_entry_cfqg(st->left); | |
a6032710 GJ |
561 | st->min_vdisktime = max_vdisktime(st->min_vdisktime, |
562 | cfqg->vdisktime); | |
25bc6b07 | 563 | } |
25bc6b07 VG |
564 | } |
565 | ||
5db5d642 CZ |
566 | /* |
567 | * get averaged number of queues of RT/BE priority. | |
568 | * average is updated, with a formula that gives more weight to higher numbers, | |
569 | * to quickly follows sudden increases and decrease slowly | |
570 | */ | |
571 | ||
58ff82f3 VG |
572 | static inline unsigned cfq_group_get_avg_queues(struct cfq_data *cfqd, |
573 | struct cfq_group *cfqg, bool rt) | |
5869619c | 574 | { |
5db5d642 CZ |
575 | unsigned min_q, max_q; |
576 | unsigned mult = cfq_hist_divisor - 1; | |
577 | unsigned round = cfq_hist_divisor / 2; | |
58ff82f3 | 578 | unsigned busy = cfq_group_busy_queues_wl(rt, cfqd, cfqg); |
5db5d642 | 579 | |
58ff82f3 VG |
580 | min_q = min(cfqg->busy_queues_avg[rt], busy); |
581 | max_q = max(cfqg->busy_queues_avg[rt], busy); | |
582 | cfqg->busy_queues_avg[rt] = (mult * max_q + min_q + round) / | |
5db5d642 | 583 | cfq_hist_divisor; |
58ff82f3 VG |
584 | return cfqg->busy_queues_avg[rt]; |
585 | } | |
586 | ||
587 | static inline unsigned | |
588 | cfq_group_slice(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
589 | { | |
590 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
591 | ||
592 | return cfq_target_latency * cfqg->weight / st->total_weight; | |
5db5d642 CZ |
593 | } |
594 | ||
c553f8e3 | 595 | static inline unsigned |
ba5bd520 | 596 | cfq_scaled_cfqq_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
44f7c160 | 597 | { |
5db5d642 CZ |
598 | unsigned slice = cfq_prio_to_slice(cfqd, cfqq); |
599 | if (cfqd->cfq_latency) { | |
58ff82f3 VG |
600 | /* |
601 | * interested queues (we consider only the ones with the same | |
602 | * priority class in the cfq group) | |
603 | */ | |
604 | unsigned iq = cfq_group_get_avg_queues(cfqd, cfqq->cfqg, | |
605 | cfq_class_rt(cfqq)); | |
5db5d642 CZ |
606 | unsigned sync_slice = cfqd->cfq_slice[1]; |
607 | unsigned expect_latency = sync_slice * iq; | |
58ff82f3 VG |
608 | unsigned group_slice = cfq_group_slice(cfqd, cfqq->cfqg); |
609 | ||
610 | if (expect_latency > group_slice) { | |
5db5d642 CZ |
611 | unsigned base_low_slice = 2 * cfqd->cfq_slice_idle; |
612 | /* scale low_slice according to IO priority | |
613 | * and sync vs async */ | |
614 | unsigned low_slice = | |
615 | min(slice, base_low_slice * slice / sync_slice); | |
616 | /* the adapted slice value is scaled to fit all iqs | |
617 | * into the target latency */ | |
58ff82f3 | 618 | slice = max(slice * group_slice / expect_latency, |
5db5d642 CZ |
619 | low_slice); |
620 | } | |
621 | } | |
c553f8e3 SL |
622 | return slice; |
623 | } | |
624 | ||
625 | static inline void | |
626 | cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
627 | { | |
ba5bd520 | 628 | unsigned slice = cfq_scaled_cfqq_slice(cfqd, cfqq); |
c553f8e3 | 629 | |
dae739eb | 630 | cfqq->slice_start = jiffies; |
5db5d642 | 631 | cfqq->slice_end = jiffies + slice; |
f75edf2d | 632 | cfqq->allocated_slice = slice; |
7b679138 | 633 | cfq_log_cfqq(cfqd, cfqq, "set_slice=%lu", cfqq->slice_end - jiffies); |
44f7c160 JA |
634 | } |
635 | ||
636 | /* | |
637 | * We need to wrap this check in cfq_cfqq_slice_new(), since ->slice_end | |
638 | * isn't valid until the first request from the dispatch is activated | |
639 | * and the slice time set. | |
640 | */ | |
a6151c3a | 641 | static inline bool cfq_slice_used(struct cfq_queue *cfqq) |
44f7c160 JA |
642 | { |
643 | if (cfq_cfqq_slice_new(cfqq)) | |
c1e44756 | 644 | return false; |
44f7c160 | 645 | if (time_before(jiffies, cfqq->slice_end)) |
c1e44756 | 646 | return false; |
44f7c160 | 647 | |
c1e44756 | 648 | return true; |
44f7c160 JA |
649 | } |
650 | ||
1da177e4 | 651 | /* |
5e705374 | 652 | * Lifted from AS - choose which of rq1 and rq2 that is best served now. |
1da177e4 | 653 | * We choose the request that is closest to the head right now. Distance |
e8a99053 | 654 | * behind the head is penalized and only allowed to a certain extent. |
1da177e4 | 655 | */ |
5e705374 | 656 | static struct request * |
cf7c25cf | 657 | cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2, sector_t last) |
1da177e4 | 658 | { |
cf7c25cf | 659 | sector_t s1, s2, d1 = 0, d2 = 0; |
1da177e4 | 660 | unsigned long back_max; |
e8a99053 AM |
661 | #define CFQ_RQ1_WRAP 0x01 /* request 1 wraps */ |
662 | #define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */ | |
663 | unsigned wrap = 0; /* bit mask: requests behind the disk head? */ | |
1da177e4 | 664 | |
5e705374 JA |
665 | if (rq1 == NULL || rq1 == rq2) |
666 | return rq2; | |
667 | if (rq2 == NULL) | |
668 | return rq1; | |
9c2c38a1 | 669 | |
5e705374 JA |
670 | if (rq_is_sync(rq1) && !rq_is_sync(rq2)) |
671 | return rq1; | |
672 | else if (rq_is_sync(rq2) && !rq_is_sync(rq1)) | |
673 | return rq2; | |
7b6d91da | 674 | if ((rq1->cmd_flags & REQ_META) && !(rq2->cmd_flags & REQ_META)) |
374f84ac | 675 | return rq1; |
7b6d91da CH |
676 | else if ((rq2->cmd_flags & REQ_META) && |
677 | !(rq1->cmd_flags & REQ_META)) | |
374f84ac | 678 | return rq2; |
1da177e4 | 679 | |
83096ebf TH |
680 | s1 = blk_rq_pos(rq1); |
681 | s2 = blk_rq_pos(rq2); | |
1da177e4 | 682 | |
1da177e4 LT |
683 | /* |
684 | * by definition, 1KiB is 2 sectors | |
685 | */ | |
686 | back_max = cfqd->cfq_back_max * 2; | |
687 | ||
688 | /* | |
689 | * Strict one way elevator _except_ in the case where we allow | |
690 | * short backward seeks which are biased as twice the cost of a | |
691 | * similar forward seek. | |
692 | */ | |
693 | if (s1 >= last) | |
694 | d1 = s1 - last; | |
695 | else if (s1 + back_max >= last) | |
696 | d1 = (last - s1) * cfqd->cfq_back_penalty; | |
697 | else | |
e8a99053 | 698 | wrap |= CFQ_RQ1_WRAP; |
1da177e4 LT |
699 | |
700 | if (s2 >= last) | |
701 | d2 = s2 - last; | |
702 | else if (s2 + back_max >= last) | |
703 | d2 = (last - s2) * cfqd->cfq_back_penalty; | |
704 | else | |
e8a99053 | 705 | wrap |= CFQ_RQ2_WRAP; |
1da177e4 LT |
706 | |
707 | /* Found required data */ | |
e8a99053 AM |
708 | |
709 | /* | |
710 | * By doing switch() on the bit mask "wrap" we avoid having to | |
711 | * check two variables for all permutations: --> faster! | |
712 | */ | |
713 | switch (wrap) { | |
5e705374 | 714 | case 0: /* common case for CFQ: rq1 and rq2 not wrapped */ |
e8a99053 | 715 | if (d1 < d2) |
5e705374 | 716 | return rq1; |
e8a99053 | 717 | else if (d2 < d1) |
5e705374 | 718 | return rq2; |
e8a99053 AM |
719 | else { |
720 | if (s1 >= s2) | |
5e705374 | 721 | return rq1; |
e8a99053 | 722 | else |
5e705374 | 723 | return rq2; |
e8a99053 | 724 | } |
1da177e4 | 725 | |
e8a99053 | 726 | case CFQ_RQ2_WRAP: |
5e705374 | 727 | return rq1; |
e8a99053 | 728 | case CFQ_RQ1_WRAP: |
5e705374 JA |
729 | return rq2; |
730 | case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both rqs wrapped */ | |
e8a99053 AM |
731 | default: |
732 | /* | |
733 | * Since both rqs are wrapped, | |
734 | * start with the one that's further behind head | |
735 | * (--> only *one* back seek required), | |
736 | * since back seek takes more time than forward. | |
737 | */ | |
738 | if (s1 <= s2) | |
5e705374 | 739 | return rq1; |
1da177e4 | 740 | else |
5e705374 | 741 | return rq2; |
1da177e4 LT |
742 | } |
743 | } | |
744 | ||
498d3aa2 JA |
745 | /* |
746 | * The below is leftmost cache rbtree addon | |
747 | */ | |
0871714e | 748 | static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root) |
cc09e299 | 749 | { |
615f0259 VG |
750 | /* Service tree is empty */ |
751 | if (!root->count) | |
752 | return NULL; | |
753 | ||
cc09e299 JA |
754 | if (!root->left) |
755 | root->left = rb_first(&root->rb); | |
756 | ||
0871714e JA |
757 | if (root->left) |
758 | return rb_entry(root->left, struct cfq_queue, rb_node); | |
759 | ||
760 | return NULL; | |
cc09e299 JA |
761 | } |
762 | ||
1fa8f6d6 VG |
763 | static struct cfq_group *cfq_rb_first_group(struct cfq_rb_root *root) |
764 | { | |
765 | if (!root->left) | |
766 | root->left = rb_first(&root->rb); | |
767 | ||
768 | if (root->left) | |
769 | return rb_entry_cfqg(root->left); | |
770 | ||
771 | return NULL; | |
772 | } | |
773 | ||
a36e71f9 JA |
774 | static void rb_erase_init(struct rb_node *n, struct rb_root *root) |
775 | { | |
776 | rb_erase(n, root); | |
777 | RB_CLEAR_NODE(n); | |
778 | } | |
779 | ||
cc09e299 JA |
780 | static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root) |
781 | { | |
782 | if (root->left == n) | |
783 | root->left = NULL; | |
a36e71f9 | 784 | rb_erase_init(n, &root->rb); |
aa6f6a3d | 785 | --root->count; |
cc09e299 JA |
786 | } |
787 | ||
1da177e4 LT |
788 | /* |
789 | * would be nice to take fifo expire time into account as well | |
790 | */ | |
5e705374 JA |
791 | static struct request * |
792 | cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
793 | struct request *last) | |
1da177e4 | 794 | { |
21183b07 JA |
795 | struct rb_node *rbnext = rb_next(&last->rb_node); |
796 | struct rb_node *rbprev = rb_prev(&last->rb_node); | |
5e705374 | 797 | struct request *next = NULL, *prev = NULL; |
1da177e4 | 798 | |
21183b07 | 799 | BUG_ON(RB_EMPTY_NODE(&last->rb_node)); |
1da177e4 LT |
800 | |
801 | if (rbprev) | |
5e705374 | 802 | prev = rb_entry_rq(rbprev); |
1da177e4 | 803 | |
21183b07 | 804 | if (rbnext) |
5e705374 | 805 | next = rb_entry_rq(rbnext); |
21183b07 JA |
806 | else { |
807 | rbnext = rb_first(&cfqq->sort_list); | |
808 | if (rbnext && rbnext != &last->rb_node) | |
5e705374 | 809 | next = rb_entry_rq(rbnext); |
21183b07 | 810 | } |
1da177e4 | 811 | |
cf7c25cf | 812 | return cfq_choose_req(cfqd, next, prev, blk_rq_pos(last)); |
1da177e4 LT |
813 | } |
814 | ||
d9e7620e JA |
815 | static unsigned long cfq_slice_offset(struct cfq_data *cfqd, |
816 | struct cfq_queue *cfqq) | |
1da177e4 | 817 | { |
d9e7620e JA |
818 | /* |
819 | * just an approximation, should be ok. | |
820 | */ | |
cdb16e8f | 821 | return (cfqq->cfqg->nr_cfqq - 1) * (cfq_prio_slice(cfqd, 1, 0) - |
464191c6 | 822 | cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio)); |
d9e7620e JA |
823 | } |
824 | ||
1fa8f6d6 VG |
825 | static inline s64 |
826 | cfqg_key(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
827 | { | |
828 | return cfqg->vdisktime - st->min_vdisktime; | |
829 | } | |
830 | ||
831 | static void | |
832 | __cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
833 | { | |
834 | struct rb_node **node = &st->rb.rb_node; | |
835 | struct rb_node *parent = NULL; | |
836 | struct cfq_group *__cfqg; | |
837 | s64 key = cfqg_key(st, cfqg); | |
838 | int left = 1; | |
839 | ||
840 | while (*node != NULL) { | |
841 | parent = *node; | |
842 | __cfqg = rb_entry_cfqg(parent); | |
843 | ||
844 | if (key < cfqg_key(st, __cfqg)) | |
845 | node = &parent->rb_left; | |
846 | else { | |
847 | node = &parent->rb_right; | |
848 | left = 0; | |
849 | } | |
850 | } | |
851 | ||
852 | if (left) | |
853 | st->left = &cfqg->rb_node; | |
854 | ||
855 | rb_link_node(&cfqg->rb_node, parent, node); | |
856 | rb_insert_color(&cfqg->rb_node, &st->rb); | |
857 | } | |
858 | ||
859 | static void | |
8184f93e JT |
860 | cfq_update_group_weight(struct cfq_group *cfqg) |
861 | { | |
862 | BUG_ON(!RB_EMPTY_NODE(&cfqg->rb_node)); | |
863 | if (cfqg->needs_update) { | |
864 | cfqg->weight = cfqg->new_weight; | |
865 | cfqg->needs_update = false; | |
866 | } | |
867 | } | |
868 | ||
869 | static void | |
870 | cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
871 | { | |
872 | BUG_ON(!RB_EMPTY_NODE(&cfqg->rb_node)); | |
873 | ||
874 | cfq_update_group_weight(cfqg); | |
875 | __cfq_group_service_tree_add(st, cfqg); | |
876 | st->total_weight += cfqg->weight; | |
877 | } | |
878 | ||
879 | static void | |
880 | cfq_group_notify_queue_add(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
1fa8f6d6 VG |
881 | { |
882 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
883 | struct cfq_group *__cfqg; | |
884 | struct rb_node *n; | |
885 | ||
886 | cfqg->nr_cfqq++; | |
760701bf | 887 | if (!RB_EMPTY_NODE(&cfqg->rb_node)) |
1fa8f6d6 VG |
888 | return; |
889 | ||
890 | /* | |
891 | * Currently put the group at the end. Later implement something | |
892 | * so that groups get lesser vtime based on their weights, so that | |
25985edc | 893 | * if group does not loose all if it was not continuously backlogged. |
1fa8f6d6 VG |
894 | */ |
895 | n = rb_last(&st->rb); | |
896 | if (n) { | |
897 | __cfqg = rb_entry_cfqg(n); | |
898 | cfqg->vdisktime = __cfqg->vdisktime + CFQ_IDLE_DELAY; | |
899 | } else | |
900 | cfqg->vdisktime = st->min_vdisktime; | |
8184f93e JT |
901 | cfq_group_service_tree_add(st, cfqg); |
902 | } | |
1fa8f6d6 | 903 | |
8184f93e JT |
904 | static void |
905 | cfq_group_service_tree_del(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
906 | { | |
907 | st->total_weight -= cfqg->weight; | |
908 | if (!RB_EMPTY_NODE(&cfqg->rb_node)) | |
909 | cfq_rb_erase(&cfqg->rb_node, st); | |
1fa8f6d6 VG |
910 | } |
911 | ||
912 | static void | |
8184f93e | 913 | cfq_group_notify_queue_del(struct cfq_data *cfqd, struct cfq_group *cfqg) |
1fa8f6d6 VG |
914 | { |
915 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
916 | ||
917 | BUG_ON(cfqg->nr_cfqq < 1); | |
918 | cfqg->nr_cfqq--; | |
25bc6b07 | 919 | |
1fa8f6d6 VG |
920 | /* If there are other cfq queues under this group, don't delete it */ |
921 | if (cfqg->nr_cfqq) | |
922 | return; | |
923 | ||
2868ef7b | 924 | cfq_log_cfqg(cfqd, cfqg, "del_from_rr group"); |
8184f93e | 925 | cfq_group_service_tree_del(st, cfqg); |
dae739eb | 926 | cfqg->saved_workload_slice = 0; |
e98ef89b | 927 | cfq_blkiocg_update_dequeue_stats(&cfqg->blkg, 1); |
dae739eb VG |
928 | } |
929 | ||
167400d3 JT |
930 | static inline unsigned int cfq_cfqq_slice_usage(struct cfq_queue *cfqq, |
931 | unsigned int *unaccounted_time) | |
dae739eb | 932 | { |
f75edf2d | 933 | unsigned int slice_used; |
dae739eb VG |
934 | |
935 | /* | |
936 | * Queue got expired before even a single request completed or | |
937 | * got expired immediately after first request completion. | |
938 | */ | |
939 | if (!cfqq->slice_start || cfqq->slice_start == jiffies) { | |
940 | /* | |
941 | * Also charge the seek time incurred to the group, otherwise | |
942 | * if there are mutiple queues in the group, each can dispatch | |
943 | * a single request on seeky media and cause lots of seek time | |
944 | * and group will never know it. | |
945 | */ | |
946 | slice_used = max_t(unsigned, (jiffies - cfqq->dispatch_start), | |
947 | 1); | |
948 | } else { | |
949 | slice_used = jiffies - cfqq->slice_start; | |
167400d3 JT |
950 | if (slice_used > cfqq->allocated_slice) { |
951 | *unaccounted_time = slice_used - cfqq->allocated_slice; | |
f75edf2d | 952 | slice_used = cfqq->allocated_slice; |
167400d3 JT |
953 | } |
954 | if (time_after(cfqq->slice_start, cfqq->dispatch_start)) | |
955 | *unaccounted_time += cfqq->slice_start - | |
956 | cfqq->dispatch_start; | |
dae739eb VG |
957 | } |
958 | ||
dae739eb VG |
959 | return slice_used; |
960 | } | |
961 | ||
962 | static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg, | |
e5ff082e | 963 | struct cfq_queue *cfqq) |
dae739eb VG |
964 | { |
965 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
167400d3 | 966 | unsigned int used_sl, charge, unaccounted_sl = 0; |
f26bd1f0 VG |
967 | int nr_sync = cfqg->nr_cfqq - cfqg_busy_async_queues(cfqd, cfqg) |
968 | - cfqg->service_tree_idle.count; | |
969 | ||
970 | BUG_ON(nr_sync < 0); | |
167400d3 | 971 | used_sl = charge = cfq_cfqq_slice_usage(cfqq, &unaccounted_sl); |
dae739eb | 972 | |
02b35081 VG |
973 | if (iops_mode(cfqd)) |
974 | charge = cfqq->slice_dispatch; | |
975 | else if (!cfq_cfqq_sync(cfqq) && !nr_sync) | |
976 | charge = cfqq->allocated_slice; | |
dae739eb VG |
977 | |
978 | /* Can't update vdisktime while group is on service tree */ | |
8184f93e | 979 | cfq_group_service_tree_del(st, cfqg); |
02b35081 | 980 | cfqg->vdisktime += cfq_scale_slice(charge, cfqg); |
8184f93e JT |
981 | /* If a new weight was requested, update now, off tree */ |
982 | cfq_group_service_tree_add(st, cfqg); | |
dae739eb VG |
983 | |
984 | /* This group is being expired. Save the context */ | |
985 | if (time_after(cfqd->workload_expires, jiffies)) { | |
986 | cfqg->saved_workload_slice = cfqd->workload_expires | |
987 | - jiffies; | |
988 | cfqg->saved_workload = cfqd->serving_type; | |
989 | cfqg->saved_serving_prio = cfqd->serving_prio; | |
990 | } else | |
991 | cfqg->saved_workload_slice = 0; | |
2868ef7b VG |
992 | |
993 | cfq_log_cfqg(cfqd, cfqg, "served: vt=%llu min_vt=%llu", cfqg->vdisktime, | |
994 | st->min_vdisktime); | |
c4e7893e VG |
995 | cfq_log_cfqq(cfqq->cfqd, cfqq, "sl_used=%u disp=%u charge=%u iops=%u" |
996 | " sect=%u", used_sl, cfqq->slice_dispatch, charge, | |
997 | iops_mode(cfqd), cfqq->nr_sectors); | |
167400d3 JT |
998 | cfq_blkiocg_update_timeslice_used(&cfqg->blkg, used_sl, |
999 | unaccounted_sl); | |
e98ef89b | 1000 | cfq_blkiocg_set_start_empty_time(&cfqg->blkg); |
1fa8f6d6 VG |
1001 | } |
1002 | ||
25fb5169 VG |
1003 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
1004 | static inline struct cfq_group *cfqg_of_blkg(struct blkio_group *blkg) | |
1005 | { | |
1006 | if (blkg) | |
1007 | return container_of(blkg, struct cfq_group, blkg); | |
1008 | return NULL; | |
1009 | } | |
1010 | ||
fe071437 VG |
1011 | void cfq_update_blkio_group_weight(void *key, struct blkio_group *blkg, |
1012 | unsigned int weight) | |
f8d461d6 | 1013 | { |
8184f93e JT |
1014 | struct cfq_group *cfqg = cfqg_of_blkg(blkg); |
1015 | cfqg->new_weight = weight; | |
1016 | cfqg->needs_update = true; | |
f8d461d6 VG |
1017 | } |
1018 | ||
f469a7b4 VG |
1019 | static void cfq_init_add_cfqg_lists(struct cfq_data *cfqd, |
1020 | struct cfq_group *cfqg, struct blkio_cgroup *blkcg) | |
25fb5169 | 1021 | { |
22084190 VG |
1022 | struct backing_dev_info *bdi = &cfqd->queue->backing_dev_info; |
1023 | unsigned int major, minor; | |
25fb5169 | 1024 | |
f469a7b4 VG |
1025 | /* |
1026 | * Add group onto cgroup list. It might happen that bdi->dev is | |
1027 | * not initialized yet. Initialize this new group without major | |
1028 | * and minor info and this info will be filled in once a new thread | |
1029 | * comes for IO. | |
1030 | */ | |
1031 | if (bdi->dev) { | |
a74b2ada | 1032 | sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor); |
f469a7b4 VG |
1033 | cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg, |
1034 | (void *)cfqd, MKDEV(major, minor)); | |
1035 | } else | |
1036 | cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg, | |
1037 | (void *)cfqd, 0); | |
1038 | ||
1039 | cfqd->nr_blkcg_linked_grps++; | |
1040 | cfqg->weight = blkcg_get_weight(blkcg, cfqg->blkg.dev); | |
1041 | ||
1042 | /* Add group on cfqd list */ | |
1043 | hlist_add_head(&cfqg->cfqd_node, &cfqd->cfqg_list); | |
1044 | } | |
1045 | ||
1046 | /* | |
1047 | * Should be called from sleepable context. No request queue lock as per | |
1048 | * cpu stats are allocated dynamically and alloc_percpu needs to be called | |
1049 | * from sleepable context. | |
1050 | */ | |
1051 | static struct cfq_group * cfq_alloc_cfqg(struct cfq_data *cfqd) | |
1052 | { | |
1053 | struct cfq_group *cfqg = NULL; | |
5624a4e4 | 1054 | int i, j, ret; |
f469a7b4 | 1055 | struct cfq_rb_root *st; |
25fb5169 VG |
1056 | |
1057 | cfqg = kzalloc_node(sizeof(*cfqg), GFP_ATOMIC, cfqd->queue->node); | |
1058 | if (!cfqg) | |
f469a7b4 | 1059 | return NULL; |
25fb5169 | 1060 | |
25fb5169 VG |
1061 | for_each_cfqg_st(cfqg, i, j, st) |
1062 | *st = CFQ_RB_ROOT; | |
1063 | RB_CLEAR_NODE(&cfqg->rb_node); | |
1064 | ||
b1c35769 VG |
1065 | /* |
1066 | * Take the initial reference that will be released on destroy | |
1067 | * This can be thought of a joint reference by cgroup and | |
1068 | * elevator which will be dropped by either elevator exit | |
1069 | * or cgroup deletion path depending on who is exiting first. | |
1070 | */ | |
329a6781 | 1071 | cfqg->ref = 1; |
5624a4e4 VG |
1072 | |
1073 | ret = blkio_alloc_blkg_stats(&cfqg->blkg); | |
1074 | if (ret) { | |
1075 | kfree(cfqg); | |
1076 | return NULL; | |
1077 | } | |
1078 | ||
f469a7b4 VG |
1079 | return cfqg; |
1080 | } | |
1081 | ||
1082 | static struct cfq_group * | |
1083 | cfq_find_cfqg(struct cfq_data *cfqd, struct blkio_cgroup *blkcg) | |
1084 | { | |
1085 | struct cfq_group *cfqg = NULL; | |
1086 | void *key = cfqd; | |
1087 | struct backing_dev_info *bdi = &cfqd->queue->backing_dev_info; | |
1088 | unsigned int major, minor; | |
b1c35769 | 1089 | |
180be2a0 | 1090 | /* |
f469a7b4 VG |
1091 | * This is the common case when there are no blkio cgroups. |
1092 | * Avoid lookup in this case | |
180be2a0 | 1093 | */ |
f469a7b4 VG |
1094 | if (blkcg == &blkio_root_cgroup) |
1095 | cfqg = &cfqd->root_group; | |
1096 | else | |
1097 | cfqg = cfqg_of_blkg(blkiocg_lookup_group(blkcg, key)); | |
25fb5169 | 1098 | |
f469a7b4 VG |
1099 | if (cfqg && !cfqg->blkg.dev && bdi->dev && dev_name(bdi->dev)) { |
1100 | sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor); | |
1101 | cfqg->blkg.dev = MKDEV(major, minor); | |
1102 | } | |
25fb5169 | 1103 | |
25fb5169 VG |
1104 | return cfqg; |
1105 | } | |
1106 | ||
1107 | /* | |
3e59cf9d VG |
1108 | * Search for the cfq group current task belongs to. request_queue lock must |
1109 | * be held. | |
25fb5169 | 1110 | */ |
3e59cf9d | 1111 | static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd) |
25fb5169 | 1112 | { |
70087dc3 | 1113 | struct blkio_cgroup *blkcg; |
f469a7b4 VG |
1114 | struct cfq_group *cfqg = NULL, *__cfqg = NULL; |
1115 | struct request_queue *q = cfqd->queue; | |
25fb5169 VG |
1116 | |
1117 | rcu_read_lock(); | |
70087dc3 | 1118 | blkcg = task_blkio_cgroup(current); |
f469a7b4 VG |
1119 | cfqg = cfq_find_cfqg(cfqd, blkcg); |
1120 | if (cfqg) { | |
1121 | rcu_read_unlock(); | |
1122 | return cfqg; | |
1123 | } | |
1124 | ||
1125 | /* | |
1126 | * Need to allocate a group. Allocation of group also needs allocation | |
1127 | * of per cpu stats which in-turn takes a mutex() and can block. Hence | |
1128 | * we need to drop rcu lock and queue_lock before we call alloc. | |
1129 | * | |
1130 | * Not taking any queue reference here and assuming that queue is | |
1131 | * around by the time we return. CFQ queue allocation code does | |
1132 | * the same. It might be racy though. | |
1133 | */ | |
1134 | ||
1135 | rcu_read_unlock(); | |
1136 | spin_unlock_irq(q->queue_lock); | |
1137 | ||
1138 | cfqg = cfq_alloc_cfqg(cfqd); | |
1139 | ||
1140 | spin_lock_irq(q->queue_lock); | |
1141 | ||
1142 | rcu_read_lock(); | |
1143 | blkcg = task_blkio_cgroup(current); | |
1144 | ||
1145 | /* | |
1146 | * If some other thread already allocated the group while we were | |
1147 | * not holding queue lock, free up the group | |
1148 | */ | |
1149 | __cfqg = cfq_find_cfqg(cfqd, blkcg); | |
1150 | ||
1151 | if (__cfqg) { | |
1152 | kfree(cfqg); | |
1153 | rcu_read_unlock(); | |
1154 | return __cfqg; | |
1155 | } | |
1156 | ||
3e59cf9d | 1157 | if (!cfqg) |
25fb5169 | 1158 | cfqg = &cfqd->root_group; |
f469a7b4 VG |
1159 | |
1160 | cfq_init_add_cfqg_lists(cfqd, cfqg, blkcg); | |
25fb5169 VG |
1161 | rcu_read_unlock(); |
1162 | return cfqg; | |
1163 | } | |
1164 | ||
7f1dc8a2 VG |
1165 | static inline struct cfq_group *cfq_ref_get_cfqg(struct cfq_group *cfqg) |
1166 | { | |
329a6781 | 1167 | cfqg->ref++; |
7f1dc8a2 VG |
1168 | return cfqg; |
1169 | } | |
1170 | ||
25fb5169 VG |
1171 | static void cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) |
1172 | { | |
1173 | /* Currently, all async queues are mapped to root group */ | |
1174 | if (!cfq_cfqq_sync(cfqq)) | |
1175 | cfqg = &cfqq->cfqd->root_group; | |
1176 | ||
1177 | cfqq->cfqg = cfqg; | |
b1c35769 | 1178 | /* cfqq reference on cfqg */ |
329a6781 | 1179 | cfqq->cfqg->ref++; |
b1c35769 VG |
1180 | } |
1181 | ||
1182 | static void cfq_put_cfqg(struct cfq_group *cfqg) | |
1183 | { | |
1184 | struct cfq_rb_root *st; | |
1185 | int i, j; | |
1186 | ||
329a6781 SL |
1187 | BUG_ON(cfqg->ref <= 0); |
1188 | cfqg->ref--; | |
1189 | if (cfqg->ref) | |
b1c35769 VG |
1190 | return; |
1191 | for_each_cfqg_st(cfqg, i, j, st) | |
b54ce60e | 1192 | BUG_ON(!RB_EMPTY_ROOT(&st->rb)); |
5624a4e4 | 1193 | free_percpu(cfqg->blkg.stats_cpu); |
b1c35769 VG |
1194 | kfree(cfqg); |
1195 | } | |
1196 | ||
1197 | static void cfq_destroy_cfqg(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
1198 | { | |
1199 | /* Something wrong if we are trying to remove same group twice */ | |
1200 | BUG_ON(hlist_unhashed(&cfqg->cfqd_node)); | |
1201 | ||
1202 | hlist_del_init(&cfqg->cfqd_node); | |
1203 | ||
1204 | /* | |
1205 | * Put the reference taken at the time of creation so that when all | |
1206 | * queues are gone, group can be destroyed. | |
1207 | */ | |
1208 | cfq_put_cfqg(cfqg); | |
1209 | } | |
1210 | ||
1211 | static void cfq_release_cfq_groups(struct cfq_data *cfqd) | |
1212 | { | |
1213 | struct hlist_node *pos, *n; | |
1214 | struct cfq_group *cfqg; | |
1215 | ||
1216 | hlist_for_each_entry_safe(cfqg, pos, n, &cfqd->cfqg_list, cfqd_node) { | |
1217 | /* | |
1218 | * If cgroup removal path got to blk_group first and removed | |
1219 | * it from cgroup list, then it will take care of destroying | |
1220 | * cfqg also. | |
1221 | */ | |
e98ef89b | 1222 | if (!cfq_blkiocg_del_blkio_group(&cfqg->blkg)) |
b1c35769 VG |
1223 | cfq_destroy_cfqg(cfqd, cfqg); |
1224 | } | |
25fb5169 | 1225 | } |
b1c35769 VG |
1226 | |
1227 | /* | |
1228 | * Blk cgroup controller notification saying that blkio_group object is being | |
1229 | * delinked as associated cgroup object is going away. That also means that | |
1230 | * no new IO will come in this group. So get rid of this group as soon as | |
1231 | * any pending IO in the group is finished. | |
1232 | * | |
1233 | * This function is called under rcu_read_lock(). key is the rcu protected | |
1234 | * pointer. That means "key" is a valid cfq_data pointer as long as we are rcu | |
1235 | * read lock. | |
1236 | * | |
1237 | * "key" was fetched from blkio_group under blkio_cgroup->lock. That means | |
1238 | * it should not be NULL as even if elevator was exiting, cgroup deltion | |
1239 | * path got to it first. | |
1240 | */ | |
1241 | void cfq_unlink_blkio_group(void *key, struct blkio_group *blkg) | |
1242 | { | |
1243 | unsigned long flags; | |
1244 | struct cfq_data *cfqd = key; | |
1245 | ||
1246 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
1247 | cfq_destroy_cfqg(cfqd, cfqg_of_blkg(blkg)); | |
1248 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
1249 | } | |
1250 | ||
25fb5169 | 1251 | #else /* GROUP_IOSCHED */ |
3e59cf9d | 1252 | static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd) |
25fb5169 VG |
1253 | { |
1254 | return &cfqd->root_group; | |
1255 | } | |
7f1dc8a2 VG |
1256 | |
1257 | static inline struct cfq_group *cfq_ref_get_cfqg(struct cfq_group *cfqg) | |
1258 | { | |
50eaeb32 | 1259 | return cfqg; |
7f1dc8a2 VG |
1260 | } |
1261 | ||
25fb5169 VG |
1262 | static inline void |
1263 | cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) { | |
1264 | cfqq->cfqg = cfqg; | |
1265 | } | |
1266 | ||
b1c35769 VG |
1267 | static void cfq_release_cfq_groups(struct cfq_data *cfqd) {} |
1268 | static inline void cfq_put_cfqg(struct cfq_group *cfqg) {} | |
1269 | ||
25fb5169 VG |
1270 | #endif /* GROUP_IOSCHED */ |
1271 | ||
498d3aa2 | 1272 | /* |
c0324a02 | 1273 | * The cfqd->service_trees holds all pending cfq_queue's that have |
498d3aa2 JA |
1274 | * requests waiting to be processed. It is sorted in the order that |
1275 | * we will service the queues. | |
1276 | */ | |
a36e71f9 | 1277 | static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
a6151c3a | 1278 | bool add_front) |
d9e7620e | 1279 | { |
0871714e JA |
1280 | struct rb_node **p, *parent; |
1281 | struct cfq_queue *__cfqq; | |
d9e7620e | 1282 | unsigned long rb_key; |
c0324a02 | 1283 | struct cfq_rb_root *service_tree; |
498d3aa2 | 1284 | int left; |
dae739eb | 1285 | int new_cfqq = 1; |
ae30c286 VG |
1286 | int group_changed = 0; |
1287 | ||
cdb16e8f | 1288 | service_tree = service_tree_for(cfqq->cfqg, cfqq_prio(cfqq), |
65b32a57 | 1289 | cfqq_type(cfqq)); |
0871714e JA |
1290 | if (cfq_class_idle(cfqq)) { |
1291 | rb_key = CFQ_IDLE_DELAY; | |
aa6f6a3d | 1292 | parent = rb_last(&service_tree->rb); |
0871714e JA |
1293 | if (parent && parent != &cfqq->rb_node) { |
1294 | __cfqq = rb_entry(parent, struct cfq_queue, rb_node); | |
1295 | rb_key += __cfqq->rb_key; | |
1296 | } else | |
1297 | rb_key += jiffies; | |
1298 | } else if (!add_front) { | |
b9c8946b JA |
1299 | /* |
1300 | * Get our rb key offset. Subtract any residual slice | |
1301 | * value carried from last service. A negative resid | |
1302 | * count indicates slice overrun, and this should position | |
1303 | * the next service time further away in the tree. | |
1304 | */ | |
edd75ffd | 1305 | rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies; |
b9c8946b | 1306 | rb_key -= cfqq->slice_resid; |
edd75ffd | 1307 | cfqq->slice_resid = 0; |
48e025e6 CZ |
1308 | } else { |
1309 | rb_key = -HZ; | |
aa6f6a3d | 1310 | __cfqq = cfq_rb_first(service_tree); |
48e025e6 CZ |
1311 | rb_key += __cfqq ? __cfqq->rb_key : jiffies; |
1312 | } | |
1da177e4 | 1313 | |
d9e7620e | 1314 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) { |
dae739eb | 1315 | new_cfqq = 0; |
99f9628a | 1316 | /* |
d9e7620e | 1317 | * same position, nothing more to do |
99f9628a | 1318 | */ |
c0324a02 CZ |
1319 | if (rb_key == cfqq->rb_key && |
1320 | cfqq->service_tree == service_tree) | |
d9e7620e | 1321 | return; |
1da177e4 | 1322 | |
aa6f6a3d CZ |
1323 | cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree); |
1324 | cfqq->service_tree = NULL; | |
1da177e4 | 1325 | } |
d9e7620e | 1326 | |
498d3aa2 | 1327 | left = 1; |
0871714e | 1328 | parent = NULL; |
aa6f6a3d CZ |
1329 | cfqq->service_tree = service_tree; |
1330 | p = &service_tree->rb.rb_node; | |
d9e7620e | 1331 | while (*p) { |
67060e37 | 1332 | struct rb_node **n; |
cc09e299 | 1333 | |
d9e7620e JA |
1334 | parent = *p; |
1335 | __cfqq = rb_entry(parent, struct cfq_queue, rb_node); | |
1336 | ||
0c534e0a | 1337 | /* |
c0324a02 | 1338 | * sort by key, that represents service time. |
0c534e0a | 1339 | */ |
c0324a02 | 1340 | if (time_before(rb_key, __cfqq->rb_key)) |
67060e37 | 1341 | n = &(*p)->rb_left; |
c0324a02 | 1342 | else { |
67060e37 | 1343 | n = &(*p)->rb_right; |
cc09e299 | 1344 | left = 0; |
c0324a02 | 1345 | } |
67060e37 JA |
1346 | |
1347 | p = n; | |
d9e7620e JA |
1348 | } |
1349 | ||
cc09e299 | 1350 | if (left) |
aa6f6a3d | 1351 | service_tree->left = &cfqq->rb_node; |
cc09e299 | 1352 | |
d9e7620e JA |
1353 | cfqq->rb_key = rb_key; |
1354 | rb_link_node(&cfqq->rb_node, parent, p); | |
aa6f6a3d CZ |
1355 | rb_insert_color(&cfqq->rb_node, &service_tree->rb); |
1356 | service_tree->count++; | |
ae30c286 | 1357 | if ((add_front || !new_cfqq) && !group_changed) |
dae739eb | 1358 | return; |
8184f93e | 1359 | cfq_group_notify_queue_add(cfqd, cfqq->cfqg); |
1da177e4 LT |
1360 | } |
1361 | ||
a36e71f9 | 1362 | static struct cfq_queue * |
f2d1f0ae JA |
1363 | cfq_prio_tree_lookup(struct cfq_data *cfqd, struct rb_root *root, |
1364 | sector_t sector, struct rb_node **ret_parent, | |
1365 | struct rb_node ***rb_link) | |
a36e71f9 | 1366 | { |
a36e71f9 JA |
1367 | struct rb_node **p, *parent; |
1368 | struct cfq_queue *cfqq = NULL; | |
1369 | ||
1370 | parent = NULL; | |
1371 | p = &root->rb_node; | |
1372 | while (*p) { | |
1373 | struct rb_node **n; | |
1374 | ||
1375 | parent = *p; | |
1376 | cfqq = rb_entry(parent, struct cfq_queue, p_node); | |
1377 | ||
1378 | /* | |
1379 | * Sort strictly based on sector. Smallest to the left, | |
1380 | * largest to the right. | |
1381 | */ | |
2e46e8b2 | 1382 | if (sector > blk_rq_pos(cfqq->next_rq)) |
a36e71f9 | 1383 | n = &(*p)->rb_right; |
2e46e8b2 | 1384 | else if (sector < blk_rq_pos(cfqq->next_rq)) |
a36e71f9 JA |
1385 | n = &(*p)->rb_left; |
1386 | else | |
1387 | break; | |
1388 | p = n; | |
3ac6c9f8 | 1389 | cfqq = NULL; |
a36e71f9 JA |
1390 | } |
1391 | ||
1392 | *ret_parent = parent; | |
1393 | if (rb_link) | |
1394 | *rb_link = p; | |
3ac6c9f8 | 1395 | return cfqq; |
a36e71f9 JA |
1396 | } |
1397 | ||
1398 | static void cfq_prio_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1399 | { | |
a36e71f9 JA |
1400 | struct rb_node **p, *parent; |
1401 | struct cfq_queue *__cfqq; | |
1402 | ||
f2d1f0ae JA |
1403 | if (cfqq->p_root) { |
1404 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
1405 | cfqq->p_root = NULL; | |
1406 | } | |
a36e71f9 JA |
1407 | |
1408 | if (cfq_class_idle(cfqq)) | |
1409 | return; | |
1410 | if (!cfqq->next_rq) | |
1411 | return; | |
1412 | ||
f2d1f0ae | 1413 | cfqq->p_root = &cfqd->prio_trees[cfqq->org_ioprio]; |
2e46e8b2 TH |
1414 | __cfqq = cfq_prio_tree_lookup(cfqd, cfqq->p_root, |
1415 | blk_rq_pos(cfqq->next_rq), &parent, &p); | |
3ac6c9f8 JA |
1416 | if (!__cfqq) { |
1417 | rb_link_node(&cfqq->p_node, parent, p); | |
f2d1f0ae JA |
1418 | rb_insert_color(&cfqq->p_node, cfqq->p_root); |
1419 | } else | |
1420 | cfqq->p_root = NULL; | |
a36e71f9 JA |
1421 | } |
1422 | ||
498d3aa2 JA |
1423 | /* |
1424 | * Update cfqq's position in the service tree. | |
1425 | */ | |
edd75ffd | 1426 | static void cfq_resort_rr_list(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
6d048f53 | 1427 | { |
6d048f53 JA |
1428 | /* |
1429 | * Resorting requires the cfqq to be on the RR list already. | |
1430 | */ | |
a36e71f9 | 1431 | if (cfq_cfqq_on_rr(cfqq)) { |
edd75ffd | 1432 | cfq_service_tree_add(cfqd, cfqq, 0); |
a36e71f9 JA |
1433 | cfq_prio_tree_add(cfqd, cfqq); |
1434 | } | |
6d048f53 JA |
1435 | } |
1436 | ||
1da177e4 LT |
1437 | /* |
1438 | * add to busy list of queues for service, trying to be fair in ordering | |
22e2c507 | 1439 | * the pending list according to last request service |
1da177e4 | 1440 | */ |
febffd61 | 1441 | static void cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 1442 | { |
7b679138 | 1443 | cfq_log_cfqq(cfqd, cfqq, "add_to_rr"); |
3b18152c JA |
1444 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
1445 | cfq_mark_cfqq_on_rr(cfqq); | |
1da177e4 | 1446 | cfqd->busy_queues++; |
ef8a41df SL |
1447 | if (cfq_cfqq_sync(cfqq)) |
1448 | cfqd->busy_sync_queues++; | |
1da177e4 | 1449 | |
edd75ffd | 1450 | cfq_resort_rr_list(cfqd, cfqq); |
1da177e4 LT |
1451 | } |
1452 | ||
498d3aa2 JA |
1453 | /* |
1454 | * Called when the cfqq no longer has requests pending, remove it from | |
1455 | * the service tree. | |
1456 | */ | |
febffd61 | 1457 | static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 1458 | { |
7b679138 | 1459 | cfq_log_cfqq(cfqd, cfqq, "del_from_rr"); |
3b18152c JA |
1460 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
1461 | cfq_clear_cfqq_on_rr(cfqq); | |
1da177e4 | 1462 | |
aa6f6a3d CZ |
1463 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) { |
1464 | cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree); | |
1465 | cfqq->service_tree = NULL; | |
1466 | } | |
f2d1f0ae JA |
1467 | if (cfqq->p_root) { |
1468 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
1469 | cfqq->p_root = NULL; | |
1470 | } | |
d9e7620e | 1471 | |
8184f93e | 1472 | cfq_group_notify_queue_del(cfqd, cfqq->cfqg); |
1da177e4 LT |
1473 | BUG_ON(!cfqd->busy_queues); |
1474 | cfqd->busy_queues--; | |
ef8a41df SL |
1475 | if (cfq_cfqq_sync(cfqq)) |
1476 | cfqd->busy_sync_queues--; | |
1da177e4 LT |
1477 | } |
1478 | ||
1479 | /* | |
1480 | * rb tree support functions | |
1481 | */ | |
febffd61 | 1482 | static void cfq_del_rq_rb(struct request *rq) |
1da177e4 | 1483 | { |
5e705374 | 1484 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
5e705374 | 1485 | const int sync = rq_is_sync(rq); |
1da177e4 | 1486 | |
b4878f24 JA |
1487 | BUG_ON(!cfqq->queued[sync]); |
1488 | cfqq->queued[sync]--; | |
1da177e4 | 1489 | |
5e705374 | 1490 | elv_rb_del(&cfqq->sort_list, rq); |
1da177e4 | 1491 | |
f04a6424 VG |
1492 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) { |
1493 | /* | |
1494 | * Queue will be deleted from service tree when we actually | |
1495 | * expire it later. Right now just remove it from prio tree | |
1496 | * as it is empty. | |
1497 | */ | |
1498 | if (cfqq->p_root) { | |
1499 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
1500 | cfqq->p_root = NULL; | |
1501 | } | |
1502 | } | |
1da177e4 LT |
1503 | } |
1504 | ||
5e705374 | 1505 | static void cfq_add_rq_rb(struct request *rq) |
1da177e4 | 1506 | { |
5e705374 | 1507 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
1da177e4 | 1508 | struct cfq_data *cfqd = cfqq->cfqd; |
a36e71f9 | 1509 | struct request *__alias, *prev; |
1da177e4 | 1510 | |
5380a101 | 1511 | cfqq->queued[rq_is_sync(rq)]++; |
1da177e4 LT |
1512 | |
1513 | /* | |
1514 | * looks a little odd, but the first insert might return an alias. | |
1515 | * if that happens, put the alias on the dispatch list | |
1516 | */ | |
21183b07 | 1517 | while ((__alias = elv_rb_add(&cfqq->sort_list, rq)) != NULL) |
5e705374 | 1518 | cfq_dispatch_insert(cfqd->queue, __alias); |
5fccbf61 JA |
1519 | |
1520 | if (!cfq_cfqq_on_rr(cfqq)) | |
1521 | cfq_add_cfqq_rr(cfqd, cfqq); | |
5044eed4 JA |
1522 | |
1523 | /* | |
1524 | * check if this request is a better next-serve candidate | |
1525 | */ | |
a36e71f9 | 1526 | prev = cfqq->next_rq; |
cf7c25cf | 1527 | cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq, cfqd->last_position); |
a36e71f9 JA |
1528 | |
1529 | /* | |
1530 | * adjust priority tree position, if ->next_rq changes | |
1531 | */ | |
1532 | if (prev != cfqq->next_rq) | |
1533 | cfq_prio_tree_add(cfqd, cfqq); | |
1534 | ||
5044eed4 | 1535 | BUG_ON(!cfqq->next_rq); |
1da177e4 LT |
1536 | } |
1537 | ||
febffd61 | 1538 | static void cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq) |
1da177e4 | 1539 | { |
5380a101 JA |
1540 | elv_rb_del(&cfqq->sort_list, rq); |
1541 | cfqq->queued[rq_is_sync(rq)]--; | |
e98ef89b VG |
1542 | cfq_blkiocg_update_io_remove_stats(&(RQ_CFQG(rq))->blkg, |
1543 | rq_data_dir(rq), rq_is_sync(rq)); | |
5e705374 | 1544 | cfq_add_rq_rb(rq); |
e98ef89b | 1545 | cfq_blkiocg_update_io_add_stats(&(RQ_CFQG(rq))->blkg, |
7f1dc8a2 VG |
1546 | &cfqq->cfqd->serving_group->blkg, rq_data_dir(rq), |
1547 | rq_is_sync(rq)); | |
1da177e4 LT |
1548 | } |
1549 | ||
206dc69b JA |
1550 | static struct request * |
1551 | cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio) | |
1da177e4 | 1552 | { |
206dc69b | 1553 | struct task_struct *tsk = current; |
91fac317 | 1554 | struct cfq_io_context *cic; |
206dc69b | 1555 | struct cfq_queue *cfqq; |
1da177e4 | 1556 | |
4ac845a2 | 1557 | cic = cfq_cic_lookup(cfqd, tsk->io_context); |
91fac317 VT |
1558 | if (!cic) |
1559 | return NULL; | |
1560 | ||
1561 | cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); | |
89850f7e JA |
1562 | if (cfqq) { |
1563 | sector_t sector = bio->bi_sector + bio_sectors(bio); | |
1564 | ||
21183b07 | 1565 | return elv_rb_find(&cfqq->sort_list, sector); |
89850f7e | 1566 | } |
1da177e4 | 1567 | |
1da177e4 LT |
1568 | return NULL; |
1569 | } | |
1570 | ||
165125e1 | 1571 | static void cfq_activate_request(struct request_queue *q, struct request *rq) |
1da177e4 | 1572 | { |
22e2c507 | 1573 | struct cfq_data *cfqd = q->elevator->elevator_data; |
3b18152c | 1574 | |
53c583d2 | 1575 | cfqd->rq_in_driver++; |
7b679138 | 1576 | cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "activate rq, drv=%d", |
53c583d2 | 1577 | cfqd->rq_in_driver); |
25776e35 | 1578 | |
5b93629b | 1579 | cfqd->last_position = blk_rq_pos(rq) + blk_rq_sectors(rq); |
1da177e4 LT |
1580 | } |
1581 | ||
165125e1 | 1582 | static void cfq_deactivate_request(struct request_queue *q, struct request *rq) |
1da177e4 | 1583 | { |
b4878f24 JA |
1584 | struct cfq_data *cfqd = q->elevator->elevator_data; |
1585 | ||
53c583d2 CZ |
1586 | WARN_ON(!cfqd->rq_in_driver); |
1587 | cfqd->rq_in_driver--; | |
7b679138 | 1588 | cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "deactivate rq, drv=%d", |
53c583d2 | 1589 | cfqd->rq_in_driver); |
1da177e4 LT |
1590 | } |
1591 | ||
b4878f24 | 1592 | static void cfq_remove_request(struct request *rq) |
1da177e4 | 1593 | { |
5e705374 | 1594 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
21183b07 | 1595 | |
5e705374 JA |
1596 | if (cfqq->next_rq == rq) |
1597 | cfqq->next_rq = cfq_find_next_rq(cfqq->cfqd, cfqq, rq); | |
1da177e4 | 1598 | |
b4878f24 | 1599 | list_del_init(&rq->queuelist); |
5e705374 | 1600 | cfq_del_rq_rb(rq); |
374f84ac | 1601 | |
45333d5a | 1602 | cfqq->cfqd->rq_queued--; |
e98ef89b VG |
1603 | cfq_blkiocg_update_io_remove_stats(&(RQ_CFQG(rq))->blkg, |
1604 | rq_data_dir(rq), rq_is_sync(rq)); | |
7b6d91da | 1605 | if (rq->cmd_flags & REQ_META) { |
374f84ac JA |
1606 | WARN_ON(!cfqq->meta_pending); |
1607 | cfqq->meta_pending--; | |
1608 | } | |
1da177e4 LT |
1609 | } |
1610 | ||
165125e1 JA |
1611 | static int cfq_merge(struct request_queue *q, struct request **req, |
1612 | struct bio *bio) | |
1da177e4 LT |
1613 | { |
1614 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1615 | struct request *__rq; | |
1da177e4 | 1616 | |
206dc69b | 1617 | __rq = cfq_find_rq_fmerge(cfqd, bio); |
22e2c507 | 1618 | if (__rq && elv_rq_merge_ok(__rq, bio)) { |
9817064b JA |
1619 | *req = __rq; |
1620 | return ELEVATOR_FRONT_MERGE; | |
1da177e4 LT |
1621 | } |
1622 | ||
1623 | return ELEVATOR_NO_MERGE; | |
1da177e4 LT |
1624 | } |
1625 | ||
165125e1 | 1626 | static void cfq_merged_request(struct request_queue *q, struct request *req, |
21183b07 | 1627 | int type) |
1da177e4 | 1628 | { |
21183b07 | 1629 | if (type == ELEVATOR_FRONT_MERGE) { |
5e705374 | 1630 | struct cfq_queue *cfqq = RQ_CFQQ(req); |
1da177e4 | 1631 | |
5e705374 | 1632 | cfq_reposition_rq_rb(cfqq, req); |
1da177e4 | 1633 | } |
1da177e4 LT |
1634 | } |
1635 | ||
812d4026 DS |
1636 | static void cfq_bio_merged(struct request_queue *q, struct request *req, |
1637 | struct bio *bio) | |
1638 | { | |
e98ef89b VG |
1639 | cfq_blkiocg_update_io_merged_stats(&(RQ_CFQG(req))->blkg, |
1640 | bio_data_dir(bio), cfq_bio_sync(bio)); | |
812d4026 DS |
1641 | } |
1642 | ||
1da177e4 | 1643 | static void |
165125e1 | 1644 | cfq_merged_requests(struct request_queue *q, struct request *rq, |
1da177e4 LT |
1645 | struct request *next) |
1646 | { | |
cf7c25cf | 1647 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 JA |
1648 | /* |
1649 | * reposition in fifo if next is older than rq | |
1650 | */ | |
1651 | if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && | |
30996f40 | 1652 | time_before(rq_fifo_time(next), rq_fifo_time(rq))) { |
22e2c507 | 1653 | list_move(&rq->queuelist, &next->queuelist); |
30996f40 JA |
1654 | rq_set_fifo_time(rq, rq_fifo_time(next)); |
1655 | } | |
22e2c507 | 1656 | |
cf7c25cf CZ |
1657 | if (cfqq->next_rq == next) |
1658 | cfqq->next_rq = rq; | |
b4878f24 | 1659 | cfq_remove_request(next); |
e98ef89b VG |
1660 | cfq_blkiocg_update_io_merged_stats(&(RQ_CFQG(rq))->blkg, |
1661 | rq_data_dir(next), rq_is_sync(next)); | |
22e2c507 JA |
1662 | } |
1663 | ||
165125e1 | 1664 | static int cfq_allow_merge(struct request_queue *q, struct request *rq, |
da775265 JA |
1665 | struct bio *bio) |
1666 | { | |
1667 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
91fac317 | 1668 | struct cfq_io_context *cic; |
da775265 | 1669 | struct cfq_queue *cfqq; |
da775265 JA |
1670 | |
1671 | /* | |
ec8acb69 | 1672 | * Disallow merge of a sync bio into an async request. |
da775265 | 1673 | */ |
91fac317 | 1674 | if (cfq_bio_sync(bio) && !rq_is_sync(rq)) |
a6151c3a | 1675 | return false; |
da775265 JA |
1676 | |
1677 | /* | |
719d3402 JA |
1678 | * Lookup the cfqq that this bio will be queued with. Allow |
1679 | * merge only if rq is queued there. | |
da775265 | 1680 | */ |
4ac845a2 | 1681 | cic = cfq_cic_lookup(cfqd, current->io_context); |
91fac317 | 1682 | if (!cic) |
a6151c3a | 1683 | return false; |
719d3402 | 1684 | |
91fac317 | 1685 | cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); |
a6151c3a | 1686 | return cfqq == RQ_CFQQ(rq); |
da775265 JA |
1687 | } |
1688 | ||
812df48d DS |
1689 | static inline void cfq_del_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1690 | { | |
1691 | del_timer(&cfqd->idle_slice_timer); | |
e98ef89b | 1692 | cfq_blkiocg_update_idle_time_stats(&cfqq->cfqg->blkg); |
812df48d DS |
1693 | } |
1694 | ||
febffd61 JA |
1695 | static void __cfq_set_active_queue(struct cfq_data *cfqd, |
1696 | struct cfq_queue *cfqq) | |
22e2c507 JA |
1697 | { |
1698 | if (cfqq) { | |
b1ffe737 DS |
1699 | cfq_log_cfqq(cfqd, cfqq, "set_active wl_prio:%d wl_type:%d", |
1700 | cfqd->serving_prio, cfqd->serving_type); | |
62a37f6b JT |
1701 | cfq_blkiocg_update_avg_queue_size_stats(&cfqq->cfqg->blkg); |
1702 | cfqq->slice_start = 0; | |
1703 | cfqq->dispatch_start = jiffies; | |
1704 | cfqq->allocated_slice = 0; | |
1705 | cfqq->slice_end = 0; | |
1706 | cfqq->slice_dispatch = 0; | |
1707 | cfqq->nr_sectors = 0; | |
1708 | ||
1709 | cfq_clear_cfqq_wait_request(cfqq); | |
1710 | cfq_clear_cfqq_must_dispatch(cfqq); | |
1711 | cfq_clear_cfqq_must_alloc_slice(cfqq); | |
1712 | cfq_clear_cfqq_fifo_expire(cfqq); | |
1713 | cfq_mark_cfqq_slice_new(cfqq); | |
1714 | ||
1715 | cfq_del_timer(cfqd, cfqq); | |
22e2c507 JA |
1716 | } |
1717 | ||
1718 | cfqd->active_queue = cfqq; | |
1719 | } | |
1720 | ||
7b14e3b5 JA |
1721 | /* |
1722 | * current cfqq expired its slice (or was too idle), select new one | |
1723 | */ | |
1724 | static void | |
1725 | __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
e5ff082e | 1726 | bool timed_out) |
7b14e3b5 | 1727 | { |
7b679138 JA |
1728 | cfq_log_cfqq(cfqd, cfqq, "slice expired t=%d", timed_out); |
1729 | ||
7b14e3b5 | 1730 | if (cfq_cfqq_wait_request(cfqq)) |
812df48d | 1731 | cfq_del_timer(cfqd, cfqq); |
7b14e3b5 | 1732 | |
7b14e3b5 | 1733 | cfq_clear_cfqq_wait_request(cfqq); |
f75edf2d | 1734 | cfq_clear_cfqq_wait_busy(cfqq); |
7b14e3b5 | 1735 | |
ae54abed SL |
1736 | /* |
1737 | * If this cfqq is shared between multiple processes, check to | |
1738 | * make sure that those processes are still issuing I/Os within | |
1739 | * the mean seek distance. If not, it may be time to break the | |
1740 | * queues apart again. | |
1741 | */ | |
1742 | if (cfq_cfqq_coop(cfqq) && CFQQ_SEEKY(cfqq)) | |
1743 | cfq_mark_cfqq_split_coop(cfqq); | |
1744 | ||
7b14e3b5 | 1745 | /* |
6084cdda | 1746 | * store what was left of this slice, if the queue idled/timed out |
7b14e3b5 | 1747 | */ |
c553f8e3 SL |
1748 | if (timed_out) { |
1749 | if (cfq_cfqq_slice_new(cfqq)) | |
ba5bd520 | 1750 | cfqq->slice_resid = cfq_scaled_cfqq_slice(cfqd, cfqq); |
c553f8e3 SL |
1751 | else |
1752 | cfqq->slice_resid = cfqq->slice_end - jiffies; | |
7b679138 JA |
1753 | cfq_log_cfqq(cfqd, cfqq, "resid=%ld", cfqq->slice_resid); |
1754 | } | |
7b14e3b5 | 1755 | |
e5ff082e | 1756 | cfq_group_served(cfqd, cfqq->cfqg, cfqq); |
dae739eb | 1757 | |
f04a6424 VG |
1758 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) |
1759 | cfq_del_cfqq_rr(cfqd, cfqq); | |
1760 | ||
edd75ffd | 1761 | cfq_resort_rr_list(cfqd, cfqq); |
7b14e3b5 JA |
1762 | |
1763 | if (cfqq == cfqd->active_queue) | |
1764 | cfqd->active_queue = NULL; | |
1765 | ||
1766 | if (cfqd->active_cic) { | |
1767 | put_io_context(cfqd->active_cic->ioc); | |
1768 | cfqd->active_cic = NULL; | |
1769 | } | |
7b14e3b5 JA |
1770 | } |
1771 | ||
e5ff082e | 1772 | static inline void cfq_slice_expired(struct cfq_data *cfqd, bool timed_out) |
7b14e3b5 JA |
1773 | { |
1774 | struct cfq_queue *cfqq = cfqd->active_queue; | |
1775 | ||
1776 | if (cfqq) | |
e5ff082e | 1777 | __cfq_slice_expired(cfqd, cfqq, timed_out); |
7b14e3b5 JA |
1778 | } |
1779 | ||
498d3aa2 JA |
1780 | /* |
1781 | * Get next queue for service. Unless we have a queue preemption, | |
1782 | * we'll simply select the first cfqq in the service tree. | |
1783 | */ | |
6d048f53 | 1784 | static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd) |
22e2c507 | 1785 | { |
c0324a02 | 1786 | struct cfq_rb_root *service_tree = |
cdb16e8f | 1787 | service_tree_for(cfqd->serving_group, cfqd->serving_prio, |
65b32a57 | 1788 | cfqd->serving_type); |
d9e7620e | 1789 | |
f04a6424 VG |
1790 | if (!cfqd->rq_queued) |
1791 | return NULL; | |
1792 | ||
1fa8f6d6 VG |
1793 | /* There is nothing to dispatch */ |
1794 | if (!service_tree) | |
1795 | return NULL; | |
c0324a02 CZ |
1796 | if (RB_EMPTY_ROOT(&service_tree->rb)) |
1797 | return NULL; | |
1798 | return cfq_rb_first(service_tree); | |
6d048f53 JA |
1799 | } |
1800 | ||
f04a6424 VG |
1801 | static struct cfq_queue *cfq_get_next_queue_forced(struct cfq_data *cfqd) |
1802 | { | |
25fb5169 | 1803 | struct cfq_group *cfqg; |
f04a6424 VG |
1804 | struct cfq_queue *cfqq; |
1805 | int i, j; | |
1806 | struct cfq_rb_root *st; | |
1807 | ||
1808 | if (!cfqd->rq_queued) | |
1809 | return NULL; | |
1810 | ||
25fb5169 VG |
1811 | cfqg = cfq_get_next_cfqg(cfqd); |
1812 | if (!cfqg) | |
1813 | return NULL; | |
1814 | ||
f04a6424 VG |
1815 | for_each_cfqg_st(cfqg, i, j, st) |
1816 | if ((cfqq = cfq_rb_first(st)) != NULL) | |
1817 | return cfqq; | |
1818 | return NULL; | |
1819 | } | |
1820 | ||
498d3aa2 JA |
1821 | /* |
1822 | * Get and set a new active queue for service. | |
1823 | */ | |
a36e71f9 JA |
1824 | static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd, |
1825 | struct cfq_queue *cfqq) | |
6d048f53 | 1826 | { |
e00ef799 | 1827 | if (!cfqq) |
a36e71f9 | 1828 | cfqq = cfq_get_next_queue(cfqd); |
6d048f53 | 1829 | |
22e2c507 | 1830 | __cfq_set_active_queue(cfqd, cfqq); |
3b18152c | 1831 | return cfqq; |
22e2c507 JA |
1832 | } |
1833 | ||
d9e7620e JA |
1834 | static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd, |
1835 | struct request *rq) | |
1836 | { | |
83096ebf TH |
1837 | if (blk_rq_pos(rq) >= cfqd->last_position) |
1838 | return blk_rq_pos(rq) - cfqd->last_position; | |
d9e7620e | 1839 | else |
83096ebf | 1840 | return cfqd->last_position - blk_rq_pos(rq); |
d9e7620e JA |
1841 | } |
1842 | ||
b2c18e1e | 1843 | static inline int cfq_rq_close(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
e9ce335d | 1844 | struct request *rq) |
6d048f53 | 1845 | { |
e9ce335d | 1846 | return cfq_dist_from_last(cfqd, rq) <= CFQQ_CLOSE_THR; |
6d048f53 JA |
1847 | } |
1848 | ||
a36e71f9 JA |
1849 | static struct cfq_queue *cfqq_close(struct cfq_data *cfqd, |
1850 | struct cfq_queue *cur_cfqq) | |
1851 | { | |
f2d1f0ae | 1852 | struct rb_root *root = &cfqd->prio_trees[cur_cfqq->org_ioprio]; |
a36e71f9 JA |
1853 | struct rb_node *parent, *node; |
1854 | struct cfq_queue *__cfqq; | |
1855 | sector_t sector = cfqd->last_position; | |
1856 | ||
1857 | if (RB_EMPTY_ROOT(root)) | |
1858 | return NULL; | |
1859 | ||
1860 | /* | |
1861 | * First, if we find a request starting at the end of the last | |
1862 | * request, choose it. | |
1863 | */ | |
f2d1f0ae | 1864 | __cfqq = cfq_prio_tree_lookup(cfqd, root, sector, &parent, NULL); |
a36e71f9 JA |
1865 | if (__cfqq) |
1866 | return __cfqq; | |
1867 | ||
1868 | /* | |
1869 | * If the exact sector wasn't found, the parent of the NULL leaf | |
1870 | * will contain the closest sector. | |
1871 | */ | |
1872 | __cfqq = rb_entry(parent, struct cfq_queue, p_node); | |
e9ce335d | 1873 | if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq)) |
a36e71f9 JA |
1874 | return __cfqq; |
1875 | ||
2e46e8b2 | 1876 | if (blk_rq_pos(__cfqq->next_rq) < sector) |
a36e71f9 JA |
1877 | node = rb_next(&__cfqq->p_node); |
1878 | else | |
1879 | node = rb_prev(&__cfqq->p_node); | |
1880 | if (!node) | |
1881 | return NULL; | |
1882 | ||
1883 | __cfqq = rb_entry(node, struct cfq_queue, p_node); | |
e9ce335d | 1884 | if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq)) |
a36e71f9 JA |
1885 | return __cfqq; |
1886 | ||
1887 | return NULL; | |
1888 | } | |
1889 | ||
1890 | /* | |
1891 | * cfqd - obvious | |
1892 | * cur_cfqq - passed in so that we don't decide that the current queue is | |
1893 | * closely cooperating with itself. | |
1894 | * | |
1895 | * So, basically we're assuming that that cur_cfqq has dispatched at least | |
1896 | * one request, and that cfqd->last_position reflects a position on the disk | |
1897 | * associated with the I/O issued by cur_cfqq. I'm not sure this is a valid | |
1898 | * assumption. | |
1899 | */ | |
1900 | static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd, | |
b3b6d040 | 1901 | struct cfq_queue *cur_cfqq) |
6d048f53 | 1902 | { |
a36e71f9 JA |
1903 | struct cfq_queue *cfqq; |
1904 | ||
39c01b21 DS |
1905 | if (cfq_class_idle(cur_cfqq)) |
1906 | return NULL; | |
e6c5bc73 JM |
1907 | if (!cfq_cfqq_sync(cur_cfqq)) |
1908 | return NULL; | |
1909 | if (CFQQ_SEEKY(cur_cfqq)) | |
1910 | return NULL; | |
1911 | ||
b9d8f4c7 GJ |
1912 | /* |
1913 | * Don't search priority tree if it's the only queue in the group. | |
1914 | */ | |
1915 | if (cur_cfqq->cfqg->nr_cfqq == 1) | |
1916 | return NULL; | |
1917 | ||
6d048f53 | 1918 | /* |
d9e7620e JA |
1919 | * We should notice if some of the queues are cooperating, eg |
1920 | * working closely on the same area of the disk. In that case, | |
1921 | * we can group them together and don't waste time idling. | |
6d048f53 | 1922 | */ |
a36e71f9 JA |
1923 | cfqq = cfqq_close(cfqd, cur_cfqq); |
1924 | if (!cfqq) | |
1925 | return NULL; | |
1926 | ||
8682e1f1 VG |
1927 | /* If new queue belongs to different cfq_group, don't choose it */ |
1928 | if (cur_cfqq->cfqg != cfqq->cfqg) | |
1929 | return NULL; | |
1930 | ||
df5fe3e8 JM |
1931 | /* |
1932 | * It only makes sense to merge sync queues. | |
1933 | */ | |
1934 | if (!cfq_cfqq_sync(cfqq)) | |
1935 | return NULL; | |
e6c5bc73 JM |
1936 | if (CFQQ_SEEKY(cfqq)) |
1937 | return NULL; | |
df5fe3e8 | 1938 | |
c0324a02 CZ |
1939 | /* |
1940 | * Do not merge queues of different priority classes | |
1941 | */ | |
1942 | if (cfq_class_rt(cfqq) != cfq_class_rt(cur_cfqq)) | |
1943 | return NULL; | |
1944 | ||
a36e71f9 | 1945 | return cfqq; |
6d048f53 JA |
1946 | } |
1947 | ||
a6d44e98 CZ |
1948 | /* |
1949 | * Determine whether we should enforce idle window for this queue. | |
1950 | */ | |
1951 | ||
1952 | static bool cfq_should_idle(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1953 | { | |
1954 | enum wl_prio_t prio = cfqq_prio(cfqq); | |
718eee05 | 1955 | struct cfq_rb_root *service_tree = cfqq->service_tree; |
a6d44e98 | 1956 | |
f04a6424 VG |
1957 | BUG_ON(!service_tree); |
1958 | BUG_ON(!service_tree->count); | |
1959 | ||
b6508c16 VG |
1960 | if (!cfqd->cfq_slice_idle) |
1961 | return false; | |
1962 | ||
a6d44e98 CZ |
1963 | /* We never do for idle class queues. */ |
1964 | if (prio == IDLE_WORKLOAD) | |
1965 | return false; | |
1966 | ||
1967 | /* We do for queues that were marked with idle window flag. */ | |
3c764b7a SL |
1968 | if (cfq_cfqq_idle_window(cfqq) && |
1969 | !(blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag)) | |
a6d44e98 CZ |
1970 | return true; |
1971 | ||
1972 | /* | |
1973 | * Otherwise, we do only if they are the last ones | |
1974 | * in their service tree. | |
1975 | */ | |
b1ffe737 | 1976 | if (service_tree->count == 1 && cfq_cfqq_sync(cfqq)) |
c1e44756 | 1977 | return true; |
b1ffe737 DS |
1978 | cfq_log_cfqq(cfqd, cfqq, "Not idling. st->count:%d", |
1979 | service_tree->count); | |
c1e44756 | 1980 | return false; |
a6d44e98 CZ |
1981 | } |
1982 | ||
6d048f53 | 1983 | static void cfq_arm_slice_timer(struct cfq_data *cfqd) |
22e2c507 | 1984 | { |
1792669c | 1985 | struct cfq_queue *cfqq = cfqd->active_queue; |
206dc69b | 1986 | struct cfq_io_context *cic; |
80bdf0c7 | 1987 | unsigned long sl, group_idle = 0; |
7b14e3b5 | 1988 | |
a68bbddb | 1989 | /* |
f7d7b7a7 JA |
1990 | * SSD device without seek penalty, disable idling. But only do so |
1991 | * for devices that support queuing, otherwise we still have a problem | |
1992 | * with sync vs async workloads. | |
a68bbddb | 1993 | */ |
f7d7b7a7 | 1994 | if (blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag) |
a68bbddb JA |
1995 | return; |
1996 | ||
dd67d051 | 1997 | WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list)); |
6d048f53 | 1998 | WARN_ON(cfq_cfqq_slice_new(cfqq)); |
22e2c507 JA |
1999 | |
2000 | /* | |
2001 | * idle is disabled, either manually or by past process history | |
2002 | */ | |
80bdf0c7 VG |
2003 | if (!cfq_should_idle(cfqd, cfqq)) { |
2004 | /* no queue idling. Check for group idling */ | |
2005 | if (cfqd->cfq_group_idle) | |
2006 | group_idle = cfqd->cfq_group_idle; | |
2007 | else | |
2008 | return; | |
2009 | } | |
6d048f53 | 2010 | |
7b679138 | 2011 | /* |
8e550632 | 2012 | * still active requests from this queue, don't idle |
7b679138 | 2013 | */ |
8e550632 | 2014 | if (cfqq->dispatched) |
7b679138 JA |
2015 | return; |
2016 | ||
22e2c507 JA |
2017 | /* |
2018 | * task has exited, don't wait | |
2019 | */ | |
206dc69b | 2020 | cic = cfqd->active_cic; |
66dac98e | 2021 | if (!cic || !atomic_read(&cic->ioc->nr_tasks)) |
6d048f53 JA |
2022 | return; |
2023 | ||
355b659c CZ |
2024 | /* |
2025 | * If our average think time is larger than the remaining time | |
2026 | * slice, then don't idle. This avoids overrunning the allotted | |
2027 | * time slice. | |
2028 | */ | |
2029 | if (sample_valid(cic->ttime_samples) && | |
b1ffe737 DS |
2030 | (cfqq->slice_end - jiffies < cic->ttime_mean)) { |
2031 | cfq_log_cfqq(cfqd, cfqq, "Not idling. think_time:%d", | |
2032 | cic->ttime_mean); | |
355b659c | 2033 | return; |
b1ffe737 | 2034 | } |
355b659c | 2035 | |
80bdf0c7 VG |
2036 | /* There are other queues in the group, don't do group idle */ |
2037 | if (group_idle && cfqq->cfqg->nr_cfqq > 1) | |
2038 | return; | |
2039 | ||
3b18152c | 2040 | cfq_mark_cfqq_wait_request(cfqq); |
22e2c507 | 2041 | |
80bdf0c7 VG |
2042 | if (group_idle) |
2043 | sl = cfqd->cfq_group_idle; | |
2044 | else | |
2045 | sl = cfqd->cfq_slice_idle; | |
206dc69b | 2046 | |
7b14e3b5 | 2047 | mod_timer(&cfqd->idle_slice_timer, jiffies + sl); |
e98ef89b | 2048 | cfq_blkiocg_update_set_idle_time_stats(&cfqq->cfqg->blkg); |
80bdf0c7 VG |
2049 | cfq_log_cfqq(cfqd, cfqq, "arm_idle: %lu group_idle: %d", sl, |
2050 | group_idle ? 1 : 0); | |
1da177e4 LT |
2051 | } |
2052 | ||
498d3aa2 JA |
2053 | /* |
2054 | * Move request from internal lists to the request queue dispatch list. | |
2055 | */ | |
165125e1 | 2056 | static void cfq_dispatch_insert(struct request_queue *q, struct request *rq) |
1da177e4 | 2057 | { |
3ed9a296 | 2058 | struct cfq_data *cfqd = q->elevator->elevator_data; |
5e705374 | 2059 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 | 2060 | |
7b679138 JA |
2061 | cfq_log_cfqq(cfqd, cfqq, "dispatch_insert"); |
2062 | ||
06d21886 | 2063 | cfqq->next_rq = cfq_find_next_rq(cfqd, cfqq, rq); |
5380a101 | 2064 | cfq_remove_request(rq); |
6d048f53 | 2065 | cfqq->dispatched++; |
80bdf0c7 | 2066 | (RQ_CFQG(rq))->dispatched++; |
5380a101 | 2067 | elv_dispatch_sort(q, rq); |
3ed9a296 | 2068 | |
53c583d2 | 2069 | cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]++; |
c4e7893e | 2070 | cfqq->nr_sectors += blk_rq_sectors(rq); |
e98ef89b | 2071 | cfq_blkiocg_update_dispatch_stats(&cfqq->cfqg->blkg, blk_rq_bytes(rq), |
84c124da | 2072 | rq_data_dir(rq), rq_is_sync(rq)); |
1da177e4 LT |
2073 | } |
2074 | ||
2075 | /* | |
2076 | * return expired entry, or NULL to just start from scratch in rbtree | |
2077 | */ | |
febffd61 | 2078 | static struct request *cfq_check_fifo(struct cfq_queue *cfqq) |
1da177e4 | 2079 | { |
30996f40 | 2080 | struct request *rq = NULL; |
1da177e4 | 2081 | |
3b18152c | 2082 | if (cfq_cfqq_fifo_expire(cfqq)) |
1da177e4 | 2083 | return NULL; |
cb887411 JA |
2084 | |
2085 | cfq_mark_cfqq_fifo_expire(cfqq); | |
2086 | ||
89850f7e JA |
2087 | if (list_empty(&cfqq->fifo)) |
2088 | return NULL; | |
1da177e4 | 2089 | |
89850f7e | 2090 | rq = rq_entry_fifo(cfqq->fifo.next); |
30996f40 | 2091 | if (time_before(jiffies, rq_fifo_time(rq))) |
7b679138 | 2092 | rq = NULL; |
1da177e4 | 2093 | |
30996f40 | 2094 | cfq_log_cfqq(cfqq->cfqd, cfqq, "fifo=%p", rq); |
6d048f53 | 2095 | return rq; |
1da177e4 LT |
2096 | } |
2097 | ||
22e2c507 JA |
2098 | static inline int |
2099 | cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
2100 | { | |
2101 | const int base_rq = cfqd->cfq_slice_async_rq; | |
1da177e4 | 2102 | |
22e2c507 | 2103 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); |
1da177e4 | 2104 | |
22e2c507 | 2105 | return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio)); |
1da177e4 LT |
2106 | } |
2107 | ||
df5fe3e8 JM |
2108 | /* |
2109 | * Must be called with the queue_lock held. | |
2110 | */ | |
2111 | static int cfqq_process_refs(struct cfq_queue *cfqq) | |
2112 | { | |
2113 | int process_refs, io_refs; | |
2114 | ||
2115 | io_refs = cfqq->allocated[READ] + cfqq->allocated[WRITE]; | |
30d7b944 | 2116 | process_refs = cfqq->ref - io_refs; |
df5fe3e8 JM |
2117 | BUG_ON(process_refs < 0); |
2118 | return process_refs; | |
2119 | } | |
2120 | ||
2121 | static void cfq_setup_merge(struct cfq_queue *cfqq, struct cfq_queue *new_cfqq) | |
2122 | { | |
e6c5bc73 | 2123 | int process_refs, new_process_refs; |
df5fe3e8 JM |
2124 | struct cfq_queue *__cfqq; |
2125 | ||
c10b61f0 JM |
2126 | /* |
2127 | * If there are no process references on the new_cfqq, then it is | |
2128 | * unsafe to follow the ->new_cfqq chain as other cfqq's in the | |
2129 | * chain may have dropped their last reference (not just their | |
2130 | * last process reference). | |
2131 | */ | |
2132 | if (!cfqq_process_refs(new_cfqq)) | |
2133 | return; | |
2134 | ||
df5fe3e8 JM |
2135 | /* Avoid a circular list and skip interim queue merges */ |
2136 | while ((__cfqq = new_cfqq->new_cfqq)) { | |
2137 | if (__cfqq == cfqq) | |
2138 | return; | |
2139 | new_cfqq = __cfqq; | |
2140 | } | |
2141 | ||
2142 | process_refs = cfqq_process_refs(cfqq); | |
c10b61f0 | 2143 | new_process_refs = cfqq_process_refs(new_cfqq); |
df5fe3e8 JM |
2144 | /* |
2145 | * If the process for the cfqq has gone away, there is no | |
2146 | * sense in merging the queues. | |
2147 | */ | |
c10b61f0 | 2148 | if (process_refs == 0 || new_process_refs == 0) |
df5fe3e8 JM |
2149 | return; |
2150 | ||
e6c5bc73 JM |
2151 | /* |
2152 | * Merge in the direction of the lesser amount of work. | |
2153 | */ | |
e6c5bc73 JM |
2154 | if (new_process_refs >= process_refs) { |
2155 | cfqq->new_cfqq = new_cfqq; | |
30d7b944 | 2156 | new_cfqq->ref += process_refs; |
e6c5bc73 JM |
2157 | } else { |
2158 | new_cfqq->new_cfqq = cfqq; | |
30d7b944 | 2159 | cfqq->ref += new_process_refs; |
e6c5bc73 | 2160 | } |
df5fe3e8 JM |
2161 | } |
2162 | ||
cdb16e8f | 2163 | static enum wl_type_t cfq_choose_wl(struct cfq_data *cfqd, |
65b32a57 | 2164 | struct cfq_group *cfqg, enum wl_prio_t prio) |
718eee05 CZ |
2165 | { |
2166 | struct cfq_queue *queue; | |
2167 | int i; | |
2168 | bool key_valid = false; | |
2169 | unsigned long lowest_key = 0; | |
2170 | enum wl_type_t cur_best = SYNC_NOIDLE_WORKLOAD; | |
2171 | ||
65b32a57 VG |
2172 | for (i = 0; i <= SYNC_WORKLOAD; ++i) { |
2173 | /* select the one with lowest rb_key */ | |
2174 | queue = cfq_rb_first(service_tree_for(cfqg, prio, i)); | |
718eee05 CZ |
2175 | if (queue && |
2176 | (!key_valid || time_before(queue->rb_key, lowest_key))) { | |
2177 | lowest_key = queue->rb_key; | |
2178 | cur_best = i; | |
2179 | key_valid = true; | |
2180 | } | |
2181 | } | |
2182 | ||
2183 | return cur_best; | |
2184 | } | |
2185 | ||
cdb16e8f | 2186 | static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg) |
718eee05 | 2187 | { |
718eee05 CZ |
2188 | unsigned slice; |
2189 | unsigned count; | |
cdb16e8f | 2190 | struct cfq_rb_root *st; |
58ff82f3 | 2191 | unsigned group_slice; |
e4ea0c16 | 2192 | enum wl_prio_t original_prio = cfqd->serving_prio; |
1fa8f6d6 | 2193 | |
718eee05 | 2194 | /* Choose next priority. RT > BE > IDLE */ |
58ff82f3 | 2195 | if (cfq_group_busy_queues_wl(RT_WORKLOAD, cfqd, cfqg)) |
718eee05 | 2196 | cfqd->serving_prio = RT_WORKLOAD; |
58ff82f3 | 2197 | else if (cfq_group_busy_queues_wl(BE_WORKLOAD, cfqd, cfqg)) |
718eee05 CZ |
2198 | cfqd->serving_prio = BE_WORKLOAD; |
2199 | else { | |
2200 | cfqd->serving_prio = IDLE_WORKLOAD; | |
2201 | cfqd->workload_expires = jiffies + 1; | |
2202 | return; | |
2203 | } | |
2204 | ||
e4ea0c16 SL |
2205 | if (original_prio != cfqd->serving_prio) |
2206 | goto new_workload; | |
2207 | ||
718eee05 CZ |
2208 | /* |
2209 | * For RT and BE, we have to choose also the type | |
2210 | * (SYNC, SYNC_NOIDLE, ASYNC), and to compute a workload | |
2211 | * expiration time | |
2212 | */ | |
65b32a57 | 2213 | st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type); |
cdb16e8f | 2214 | count = st->count; |
718eee05 CZ |
2215 | |
2216 | /* | |
65b32a57 | 2217 | * check workload expiration, and that we still have other queues ready |
718eee05 | 2218 | */ |
65b32a57 | 2219 | if (count && !time_after(jiffies, cfqd->workload_expires)) |
718eee05 CZ |
2220 | return; |
2221 | ||
e4ea0c16 | 2222 | new_workload: |
718eee05 CZ |
2223 | /* otherwise select new workload type */ |
2224 | cfqd->serving_type = | |
65b32a57 VG |
2225 | cfq_choose_wl(cfqd, cfqg, cfqd->serving_prio); |
2226 | st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type); | |
cdb16e8f | 2227 | count = st->count; |
718eee05 CZ |
2228 | |
2229 | /* | |
2230 | * the workload slice is computed as a fraction of target latency | |
2231 | * proportional to the number of queues in that workload, over | |
2232 | * all the queues in the same priority class | |
2233 | */ | |
58ff82f3 VG |
2234 | group_slice = cfq_group_slice(cfqd, cfqg); |
2235 | ||
2236 | slice = group_slice * count / | |
2237 | max_t(unsigned, cfqg->busy_queues_avg[cfqd->serving_prio], | |
2238 | cfq_group_busy_queues_wl(cfqd->serving_prio, cfqd, cfqg)); | |
718eee05 | 2239 | |
f26bd1f0 VG |
2240 | if (cfqd->serving_type == ASYNC_WORKLOAD) { |
2241 | unsigned int tmp; | |
2242 | ||
2243 | /* | |
2244 | * Async queues are currently system wide. Just taking | |
2245 | * proportion of queues with-in same group will lead to higher | |
2246 | * async ratio system wide as generally root group is going | |
2247 | * to have higher weight. A more accurate thing would be to | |
2248 | * calculate system wide asnc/sync ratio. | |
2249 | */ | |
2250 | tmp = cfq_target_latency * cfqg_busy_async_queues(cfqd, cfqg); | |
2251 | tmp = tmp/cfqd->busy_queues; | |
2252 | slice = min_t(unsigned, slice, tmp); | |
2253 | ||
718eee05 CZ |
2254 | /* async workload slice is scaled down according to |
2255 | * the sync/async slice ratio. */ | |
2256 | slice = slice * cfqd->cfq_slice[0] / cfqd->cfq_slice[1]; | |
f26bd1f0 | 2257 | } else |
718eee05 CZ |
2258 | /* sync workload slice is at least 2 * cfq_slice_idle */ |
2259 | slice = max(slice, 2 * cfqd->cfq_slice_idle); | |
2260 | ||
2261 | slice = max_t(unsigned, slice, CFQ_MIN_TT); | |
b1ffe737 | 2262 | cfq_log(cfqd, "workload slice:%d", slice); |
718eee05 CZ |
2263 | cfqd->workload_expires = jiffies + slice; |
2264 | } | |
2265 | ||
1fa8f6d6 VG |
2266 | static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd) |
2267 | { | |
2268 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
25bc6b07 | 2269 | struct cfq_group *cfqg; |
1fa8f6d6 VG |
2270 | |
2271 | if (RB_EMPTY_ROOT(&st->rb)) | |
2272 | return NULL; | |
25bc6b07 | 2273 | cfqg = cfq_rb_first_group(st); |
25bc6b07 VG |
2274 | update_min_vdisktime(st); |
2275 | return cfqg; | |
1fa8f6d6 VG |
2276 | } |
2277 | ||
cdb16e8f VG |
2278 | static void cfq_choose_cfqg(struct cfq_data *cfqd) |
2279 | { | |
1fa8f6d6 VG |
2280 | struct cfq_group *cfqg = cfq_get_next_cfqg(cfqd); |
2281 | ||
2282 | cfqd->serving_group = cfqg; | |
dae739eb VG |
2283 | |
2284 | /* Restore the workload type data */ | |
2285 | if (cfqg->saved_workload_slice) { | |
2286 | cfqd->workload_expires = jiffies + cfqg->saved_workload_slice; | |
2287 | cfqd->serving_type = cfqg->saved_workload; | |
2288 | cfqd->serving_prio = cfqg->saved_serving_prio; | |
66ae2919 GJ |
2289 | } else |
2290 | cfqd->workload_expires = jiffies - 1; | |
2291 | ||
1fa8f6d6 | 2292 | choose_service_tree(cfqd, cfqg); |
cdb16e8f VG |
2293 | } |
2294 | ||
22e2c507 | 2295 | /* |
498d3aa2 JA |
2296 | * Select a queue for service. If we have a current active queue, |
2297 | * check whether to continue servicing it, or retrieve and set a new one. | |
22e2c507 | 2298 | */ |
1b5ed5e1 | 2299 | static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) |
1da177e4 | 2300 | { |
a36e71f9 | 2301 | struct cfq_queue *cfqq, *new_cfqq = NULL; |
1da177e4 | 2302 | |
22e2c507 JA |
2303 | cfqq = cfqd->active_queue; |
2304 | if (!cfqq) | |
2305 | goto new_queue; | |
1da177e4 | 2306 | |
f04a6424 VG |
2307 | if (!cfqd->rq_queued) |
2308 | return NULL; | |
c244bb50 VG |
2309 | |
2310 | /* | |
2311 | * We were waiting for group to get backlogged. Expire the queue | |
2312 | */ | |
2313 | if (cfq_cfqq_wait_busy(cfqq) && !RB_EMPTY_ROOT(&cfqq->sort_list)) | |
2314 | goto expire; | |
2315 | ||
22e2c507 | 2316 | /* |
6d048f53 | 2317 | * The active queue has run out of time, expire it and select new. |
22e2c507 | 2318 | */ |
7667aa06 VG |
2319 | if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq)) { |
2320 | /* | |
2321 | * If slice had not expired at the completion of last request | |
2322 | * we might not have turned on wait_busy flag. Don't expire | |
2323 | * the queue yet. Allow the group to get backlogged. | |
2324 | * | |
2325 | * The very fact that we have used the slice, that means we | |
2326 | * have been idling all along on this queue and it should be | |
2327 | * ok to wait for this request to complete. | |
2328 | */ | |
82bbbf28 VG |
2329 | if (cfqq->cfqg->nr_cfqq == 1 && RB_EMPTY_ROOT(&cfqq->sort_list) |
2330 | && cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) { | |
2331 | cfqq = NULL; | |
7667aa06 | 2332 | goto keep_queue; |
82bbbf28 | 2333 | } else |
80bdf0c7 | 2334 | goto check_group_idle; |
7667aa06 | 2335 | } |
1da177e4 | 2336 | |
22e2c507 | 2337 | /* |
6d048f53 JA |
2338 | * The active queue has requests and isn't expired, allow it to |
2339 | * dispatch. | |
22e2c507 | 2340 | */ |
dd67d051 | 2341 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
22e2c507 | 2342 | goto keep_queue; |
6d048f53 | 2343 | |
a36e71f9 JA |
2344 | /* |
2345 | * If another queue has a request waiting within our mean seek | |
2346 | * distance, let it run. The expire code will check for close | |
2347 | * cooperators and put the close queue at the front of the service | |
df5fe3e8 | 2348 | * tree. If possible, merge the expiring queue with the new cfqq. |
a36e71f9 | 2349 | */ |
b3b6d040 | 2350 | new_cfqq = cfq_close_cooperator(cfqd, cfqq); |
df5fe3e8 JM |
2351 | if (new_cfqq) { |
2352 | if (!cfqq->new_cfqq) | |
2353 | cfq_setup_merge(cfqq, new_cfqq); | |
a36e71f9 | 2354 | goto expire; |
df5fe3e8 | 2355 | } |
a36e71f9 | 2356 | |
6d048f53 JA |
2357 | /* |
2358 | * No requests pending. If the active queue still has requests in | |
2359 | * flight or is idling for a new request, allow either of these | |
2360 | * conditions to happen (or time out) before selecting a new queue. | |
2361 | */ | |
80bdf0c7 VG |
2362 | if (timer_pending(&cfqd->idle_slice_timer)) { |
2363 | cfqq = NULL; | |
2364 | goto keep_queue; | |
2365 | } | |
2366 | ||
8e1ac665 SL |
2367 | /* |
2368 | * This is a deep seek queue, but the device is much faster than | |
2369 | * the queue can deliver, don't idle | |
2370 | **/ | |
2371 | if (CFQQ_SEEKY(cfqq) && cfq_cfqq_idle_window(cfqq) && | |
2372 | (cfq_cfqq_slice_new(cfqq) || | |
2373 | (cfqq->slice_end - jiffies > jiffies - cfqq->slice_start))) { | |
2374 | cfq_clear_cfqq_deep(cfqq); | |
2375 | cfq_clear_cfqq_idle_window(cfqq); | |
2376 | } | |
2377 | ||
80bdf0c7 VG |
2378 | if (cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) { |
2379 | cfqq = NULL; | |
2380 | goto keep_queue; | |
2381 | } | |
2382 | ||
2383 | /* | |
2384 | * If group idle is enabled and there are requests dispatched from | |
2385 | * this group, wait for requests to complete. | |
2386 | */ | |
2387 | check_group_idle: | |
2388 | if (cfqd->cfq_group_idle && cfqq->cfqg->nr_cfqq == 1 | |
2389 | && cfqq->cfqg->dispatched) { | |
caaa5f9f JA |
2390 | cfqq = NULL; |
2391 | goto keep_queue; | |
22e2c507 JA |
2392 | } |
2393 | ||
3b18152c | 2394 | expire: |
e5ff082e | 2395 | cfq_slice_expired(cfqd, 0); |
3b18152c | 2396 | new_queue: |
718eee05 CZ |
2397 | /* |
2398 | * Current queue expired. Check if we have to switch to a new | |
2399 | * service tree | |
2400 | */ | |
2401 | if (!new_cfqq) | |
cdb16e8f | 2402 | cfq_choose_cfqg(cfqd); |
718eee05 | 2403 | |
a36e71f9 | 2404 | cfqq = cfq_set_active_queue(cfqd, new_cfqq); |
22e2c507 | 2405 | keep_queue: |
3b18152c | 2406 | return cfqq; |
22e2c507 JA |
2407 | } |
2408 | ||
febffd61 | 2409 | static int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq) |
d9e7620e JA |
2410 | { |
2411 | int dispatched = 0; | |
2412 | ||
2413 | while (cfqq->next_rq) { | |
2414 | cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq); | |
2415 | dispatched++; | |
2416 | } | |
2417 | ||
2418 | BUG_ON(!list_empty(&cfqq->fifo)); | |
f04a6424 VG |
2419 | |
2420 | /* By default cfqq is not expired if it is empty. Do it explicitly */ | |
e5ff082e | 2421 | __cfq_slice_expired(cfqq->cfqd, cfqq, 0); |
d9e7620e JA |
2422 | return dispatched; |
2423 | } | |
2424 | ||
498d3aa2 JA |
2425 | /* |
2426 | * Drain our current requests. Used for barriers and when switching | |
2427 | * io schedulers on-the-fly. | |
2428 | */ | |
d9e7620e | 2429 | static int cfq_forced_dispatch(struct cfq_data *cfqd) |
1b5ed5e1 | 2430 | { |
0871714e | 2431 | struct cfq_queue *cfqq; |
d9e7620e | 2432 | int dispatched = 0; |
cdb16e8f | 2433 | |
3440c49f | 2434 | /* Expire the timeslice of the current active queue first */ |
e5ff082e | 2435 | cfq_slice_expired(cfqd, 0); |
3440c49f DS |
2436 | while ((cfqq = cfq_get_next_queue_forced(cfqd)) != NULL) { |
2437 | __cfq_set_active_queue(cfqd, cfqq); | |
f04a6424 | 2438 | dispatched += __cfq_forced_dispatch_cfqq(cfqq); |
3440c49f | 2439 | } |
1b5ed5e1 | 2440 | |
1b5ed5e1 TH |
2441 | BUG_ON(cfqd->busy_queues); |
2442 | ||
6923715a | 2443 | cfq_log(cfqd, "forced_dispatch=%d", dispatched); |
1b5ed5e1 TH |
2444 | return dispatched; |
2445 | } | |
2446 | ||
abc3c744 SL |
2447 | static inline bool cfq_slice_used_soon(struct cfq_data *cfqd, |
2448 | struct cfq_queue *cfqq) | |
2449 | { | |
2450 | /* the queue hasn't finished any request, can't estimate */ | |
2451 | if (cfq_cfqq_slice_new(cfqq)) | |
c1e44756 | 2452 | return true; |
abc3c744 SL |
2453 | if (time_after(jiffies + cfqd->cfq_slice_idle * cfqq->dispatched, |
2454 | cfqq->slice_end)) | |
c1e44756 | 2455 | return true; |
abc3c744 | 2456 | |
c1e44756 | 2457 | return false; |
abc3c744 SL |
2458 | } |
2459 | ||
0b182d61 | 2460 | static bool cfq_may_dispatch(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
2f5cb738 | 2461 | { |
2f5cb738 | 2462 | unsigned int max_dispatch; |
22e2c507 | 2463 | |
5ad531db JA |
2464 | /* |
2465 | * Drain async requests before we start sync IO | |
2466 | */ | |
53c583d2 | 2467 | if (cfq_should_idle(cfqd, cfqq) && cfqd->rq_in_flight[BLK_RW_ASYNC]) |
0b182d61 | 2468 | return false; |
5ad531db | 2469 | |
2f5cb738 JA |
2470 | /* |
2471 | * If this is an async queue and we have sync IO in flight, let it wait | |
2472 | */ | |
53c583d2 | 2473 | if (cfqd->rq_in_flight[BLK_RW_SYNC] && !cfq_cfqq_sync(cfqq)) |
0b182d61 | 2474 | return false; |
2f5cb738 | 2475 | |
abc3c744 | 2476 | max_dispatch = max_t(unsigned int, cfqd->cfq_quantum / 2, 1); |
2f5cb738 JA |
2477 | if (cfq_class_idle(cfqq)) |
2478 | max_dispatch = 1; | |
b4878f24 | 2479 | |
2f5cb738 JA |
2480 | /* |
2481 | * Does this cfqq already have too much IO in flight? | |
2482 | */ | |
2483 | if (cfqq->dispatched >= max_dispatch) { | |
ef8a41df | 2484 | bool promote_sync = false; |
2f5cb738 JA |
2485 | /* |
2486 | * idle queue must always only have a single IO in flight | |
2487 | */ | |
3ed9a296 | 2488 | if (cfq_class_idle(cfqq)) |
0b182d61 | 2489 | return false; |
3ed9a296 | 2490 | |
ef8a41df | 2491 | /* |
c4ade94f LS |
2492 | * If there is only one sync queue |
2493 | * we can ignore async queue here and give the sync | |
ef8a41df SL |
2494 | * queue no dispatch limit. The reason is a sync queue can |
2495 | * preempt async queue, limiting the sync queue doesn't make | |
2496 | * sense. This is useful for aiostress test. | |
2497 | */ | |
c4ade94f LS |
2498 | if (cfq_cfqq_sync(cfqq) && cfqd->busy_sync_queues == 1) |
2499 | promote_sync = true; | |
ef8a41df | 2500 | |
2f5cb738 JA |
2501 | /* |
2502 | * We have other queues, don't allow more IO from this one | |
2503 | */ | |
ef8a41df SL |
2504 | if (cfqd->busy_queues > 1 && cfq_slice_used_soon(cfqd, cfqq) && |
2505 | !promote_sync) | |
0b182d61 | 2506 | return false; |
9ede209e | 2507 | |
365722bb | 2508 | /* |
474b18cc | 2509 | * Sole queue user, no limit |
365722bb | 2510 | */ |
ef8a41df | 2511 | if (cfqd->busy_queues == 1 || promote_sync) |
abc3c744 SL |
2512 | max_dispatch = -1; |
2513 | else | |
2514 | /* | |
2515 | * Normally we start throttling cfqq when cfq_quantum/2 | |
2516 | * requests have been dispatched. But we can drive | |
2517 | * deeper queue depths at the beginning of slice | |
2518 | * subjected to upper limit of cfq_quantum. | |
2519 | * */ | |
2520 | max_dispatch = cfqd->cfq_quantum; | |
8e296755 JA |
2521 | } |
2522 | ||
2523 | /* | |
2524 | * Async queues must wait a bit before being allowed dispatch. | |
2525 | * We also ramp up the dispatch depth gradually for async IO, | |
2526 | * based on the last sync IO we serviced | |
2527 | */ | |
963b72fc | 2528 | if (!cfq_cfqq_sync(cfqq) && cfqd->cfq_latency) { |
573412b2 | 2529 | unsigned long last_sync = jiffies - cfqd->last_delayed_sync; |
8e296755 | 2530 | unsigned int depth; |
365722bb | 2531 | |
61f0c1dc | 2532 | depth = last_sync / cfqd->cfq_slice[1]; |
e00c54c3 JA |
2533 | if (!depth && !cfqq->dispatched) |
2534 | depth = 1; | |
8e296755 JA |
2535 | if (depth < max_dispatch) |
2536 | max_dispatch = depth; | |
2f5cb738 | 2537 | } |
3ed9a296 | 2538 | |
0b182d61 JA |
2539 | /* |
2540 | * If we're below the current max, allow a dispatch | |
2541 | */ | |
2542 | return cfqq->dispatched < max_dispatch; | |
2543 | } | |
2544 | ||
2545 | /* | |
2546 | * Dispatch a request from cfqq, moving them to the request queue | |
2547 | * dispatch list. | |
2548 | */ | |
2549 | static bool cfq_dispatch_request(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
2550 | { | |
2551 | struct request *rq; | |
2552 | ||
2553 | BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list)); | |
2554 | ||
2555 | if (!cfq_may_dispatch(cfqd, cfqq)) | |
2556 | return false; | |
2557 | ||
2558 | /* | |
2559 | * follow expired path, else get first next available | |
2560 | */ | |
2561 | rq = cfq_check_fifo(cfqq); | |
2562 | if (!rq) | |
2563 | rq = cfqq->next_rq; | |
2564 | ||
2565 | /* | |
2566 | * insert request into driver dispatch list | |
2567 | */ | |
2568 | cfq_dispatch_insert(cfqd->queue, rq); | |
2569 | ||
2570 | if (!cfqd->active_cic) { | |
2571 | struct cfq_io_context *cic = RQ_CIC(rq); | |
2572 | ||
2573 | atomic_long_inc(&cic->ioc->refcount); | |
2574 | cfqd->active_cic = cic; | |
2575 | } | |
2576 | ||
2577 | return true; | |
2578 | } | |
2579 | ||
2580 | /* | |
2581 | * Find the cfqq that we need to service and move a request from that to the | |
2582 | * dispatch list | |
2583 | */ | |
2584 | static int cfq_dispatch_requests(struct request_queue *q, int force) | |
2585 | { | |
2586 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
2587 | struct cfq_queue *cfqq; | |
2588 | ||
2589 | if (!cfqd->busy_queues) | |
2590 | return 0; | |
2591 | ||
2592 | if (unlikely(force)) | |
2593 | return cfq_forced_dispatch(cfqd); | |
2594 | ||
2595 | cfqq = cfq_select_queue(cfqd); | |
2596 | if (!cfqq) | |
8e296755 JA |
2597 | return 0; |
2598 | ||
2f5cb738 | 2599 | /* |
0b182d61 | 2600 | * Dispatch a request from this cfqq, if it is allowed |
2f5cb738 | 2601 | */ |
0b182d61 JA |
2602 | if (!cfq_dispatch_request(cfqd, cfqq)) |
2603 | return 0; | |
2604 | ||
2f5cb738 | 2605 | cfqq->slice_dispatch++; |
b029195d | 2606 | cfq_clear_cfqq_must_dispatch(cfqq); |
22e2c507 | 2607 | |
2f5cb738 JA |
2608 | /* |
2609 | * expire an async queue immediately if it has used up its slice. idle | |
2610 | * queue always expire after 1 dispatch round. | |
2611 | */ | |
2612 | if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) && | |
2613 | cfqq->slice_dispatch >= cfq_prio_to_maxrq(cfqd, cfqq)) || | |
2614 | cfq_class_idle(cfqq))) { | |
2615 | cfqq->slice_end = jiffies + 1; | |
e5ff082e | 2616 | cfq_slice_expired(cfqd, 0); |
1da177e4 LT |
2617 | } |
2618 | ||
b217a903 | 2619 | cfq_log_cfqq(cfqd, cfqq, "dispatched a request"); |
2f5cb738 | 2620 | return 1; |
1da177e4 LT |
2621 | } |
2622 | ||
1da177e4 | 2623 | /* |
5e705374 JA |
2624 | * task holds one reference to the queue, dropped when task exits. each rq |
2625 | * in-flight on this queue also holds a reference, dropped when rq is freed. | |
1da177e4 | 2626 | * |
b1c35769 | 2627 | * Each cfq queue took a reference on the parent group. Drop it now. |
1da177e4 LT |
2628 | * queue lock must be held here. |
2629 | */ | |
2630 | static void cfq_put_queue(struct cfq_queue *cfqq) | |
2631 | { | |
22e2c507 | 2632 | struct cfq_data *cfqd = cfqq->cfqd; |
0bbfeb83 | 2633 | struct cfq_group *cfqg; |
22e2c507 | 2634 | |
30d7b944 | 2635 | BUG_ON(cfqq->ref <= 0); |
1da177e4 | 2636 | |
30d7b944 SL |
2637 | cfqq->ref--; |
2638 | if (cfqq->ref) | |
1da177e4 LT |
2639 | return; |
2640 | ||
7b679138 | 2641 | cfq_log_cfqq(cfqd, cfqq, "put_queue"); |
1da177e4 | 2642 | BUG_ON(rb_first(&cfqq->sort_list)); |
22e2c507 | 2643 | BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]); |
b1c35769 | 2644 | cfqg = cfqq->cfqg; |
1da177e4 | 2645 | |
28f95cbc | 2646 | if (unlikely(cfqd->active_queue == cfqq)) { |
e5ff082e | 2647 | __cfq_slice_expired(cfqd, cfqq, 0); |
23e018a1 | 2648 | cfq_schedule_dispatch(cfqd); |
28f95cbc | 2649 | } |
22e2c507 | 2650 | |
f04a6424 | 2651 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
1da177e4 | 2652 | kmem_cache_free(cfq_pool, cfqq); |
b1c35769 | 2653 | cfq_put_cfqg(cfqg); |
1da177e4 LT |
2654 | } |
2655 | ||
d6de8be7 | 2656 | /* |
5f45c695 | 2657 | * Call func for each cic attached to this ioc. |
d6de8be7 | 2658 | */ |
07416d29 | 2659 | static void |
5f45c695 JA |
2660 | call_for_each_cic(struct io_context *ioc, |
2661 | void (*func)(struct io_context *, struct cfq_io_context *)) | |
07416d29 JA |
2662 | { |
2663 | struct cfq_io_context *cic; | |
2664 | struct hlist_node *n; | |
2665 | ||
5f45c695 JA |
2666 | rcu_read_lock(); |
2667 | ||
07416d29 JA |
2668 | hlist_for_each_entry_rcu(cic, n, &ioc->cic_list, cic_list) |
2669 | func(ioc, cic); | |
07416d29 | 2670 | |
4ac845a2 | 2671 | rcu_read_unlock(); |
34e6bbf2 FC |
2672 | } |
2673 | ||
2674 | static void cfq_cic_free_rcu(struct rcu_head *head) | |
2675 | { | |
2676 | struct cfq_io_context *cic; | |
2677 | ||
2678 | cic = container_of(head, struct cfq_io_context, rcu_head); | |
2679 | ||
2680 | kmem_cache_free(cfq_ioc_pool, cic); | |
245b2e70 | 2681 | elv_ioc_count_dec(cfq_ioc_count); |
34e6bbf2 | 2682 | |
9a11b4ed JA |
2683 | if (ioc_gone) { |
2684 | /* | |
2685 | * CFQ scheduler is exiting, grab exit lock and check | |
2686 | * the pending io context count. If it hits zero, | |
2687 | * complete ioc_gone and set it back to NULL | |
2688 | */ | |
2689 | spin_lock(&ioc_gone_lock); | |
245b2e70 | 2690 | if (ioc_gone && !elv_ioc_count_read(cfq_ioc_count)) { |
9a11b4ed JA |
2691 | complete(ioc_gone); |
2692 | ioc_gone = NULL; | |
2693 | } | |
2694 | spin_unlock(&ioc_gone_lock); | |
2695 | } | |
34e6bbf2 | 2696 | } |
4ac845a2 | 2697 | |
34e6bbf2 FC |
2698 | static void cfq_cic_free(struct cfq_io_context *cic) |
2699 | { | |
2700 | call_rcu(&cic->rcu_head, cfq_cic_free_rcu); | |
4ac845a2 JA |
2701 | } |
2702 | ||
2703 | static void cic_free_func(struct io_context *ioc, struct cfq_io_context *cic) | |
2704 | { | |
2705 | unsigned long flags; | |
bca4b914 | 2706 | unsigned long dead_key = (unsigned long) cic->key; |
4ac845a2 | 2707 | |
bca4b914 | 2708 | BUG_ON(!(dead_key & CIC_DEAD_KEY)); |
4ac845a2 JA |
2709 | |
2710 | spin_lock_irqsave(&ioc->lock, flags); | |
80b15c73 | 2711 | radix_tree_delete(&ioc->radix_root, dead_key >> CIC_DEAD_INDEX_SHIFT); |
ffc4e759 | 2712 | hlist_del_rcu(&cic->cic_list); |
4ac845a2 JA |
2713 | spin_unlock_irqrestore(&ioc->lock, flags); |
2714 | ||
34e6bbf2 | 2715 | cfq_cic_free(cic); |
4ac845a2 JA |
2716 | } |
2717 | ||
d6de8be7 JA |
2718 | /* |
2719 | * Must be called with rcu_read_lock() held or preemption otherwise disabled. | |
2720 | * Only two callers of this - ->dtor() which is called with the rcu_read_lock(), | |
2721 | * and ->trim() which is called with the task lock held | |
2722 | */ | |
4ac845a2 JA |
2723 | static void cfq_free_io_context(struct io_context *ioc) |
2724 | { | |
4ac845a2 | 2725 | /* |
34e6bbf2 FC |
2726 | * ioc->refcount is zero here, or we are called from elv_unregister(), |
2727 | * so no more cic's are allowed to be linked into this ioc. So it | |
2728 | * should be ok to iterate over the known list, we will see all cic's | |
2729 | * since no new ones are added. | |
4ac845a2 | 2730 | */ |
5f45c695 | 2731 | call_for_each_cic(ioc, cic_free_func); |
1da177e4 LT |
2732 | } |
2733 | ||
d02a2c07 | 2734 | static void cfq_put_cooperator(struct cfq_queue *cfqq) |
1da177e4 | 2735 | { |
df5fe3e8 JM |
2736 | struct cfq_queue *__cfqq, *next; |
2737 | ||
df5fe3e8 JM |
2738 | /* |
2739 | * If this queue was scheduled to merge with another queue, be | |
2740 | * sure to drop the reference taken on that queue (and others in | |
2741 | * the merge chain). See cfq_setup_merge and cfq_merge_cfqqs. | |
2742 | */ | |
2743 | __cfqq = cfqq->new_cfqq; | |
2744 | while (__cfqq) { | |
2745 | if (__cfqq == cfqq) { | |
2746 | WARN(1, "cfqq->new_cfqq loop detected\n"); | |
2747 | break; | |
2748 | } | |
2749 | next = __cfqq->new_cfqq; | |
2750 | cfq_put_queue(__cfqq); | |
2751 | __cfqq = next; | |
2752 | } | |
d02a2c07 SL |
2753 | } |
2754 | ||
2755 | static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
2756 | { | |
2757 | if (unlikely(cfqq == cfqd->active_queue)) { | |
2758 | __cfq_slice_expired(cfqd, cfqq, 0); | |
2759 | cfq_schedule_dispatch(cfqd); | |
2760 | } | |
2761 | ||
2762 | cfq_put_cooperator(cfqq); | |
df5fe3e8 | 2763 | |
89850f7e JA |
2764 | cfq_put_queue(cfqq); |
2765 | } | |
22e2c507 | 2766 | |
89850f7e JA |
2767 | static void __cfq_exit_single_io_context(struct cfq_data *cfqd, |
2768 | struct cfq_io_context *cic) | |
2769 | { | |
4faa3c81 FC |
2770 | struct io_context *ioc = cic->ioc; |
2771 | ||
fc46379d | 2772 | list_del_init(&cic->queue_list); |
4ac845a2 JA |
2773 | |
2774 | /* | |
bca4b914 | 2775 | * Make sure dead mark is seen for dead queues |
4ac845a2 | 2776 | */ |
fc46379d | 2777 | smp_wmb(); |
bca4b914 | 2778 | cic->key = cfqd_dead_key(cfqd); |
fc46379d | 2779 | |
4faa3c81 FC |
2780 | if (ioc->ioc_data == cic) |
2781 | rcu_assign_pointer(ioc->ioc_data, NULL); | |
2782 | ||
ff6657c6 JA |
2783 | if (cic->cfqq[BLK_RW_ASYNC]) { |
2784 | cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_ASYNC]); | |
2785 | cic->cfqq[BLK_RW_ASYNC] = NULL; | |
12a05732 AV |
2786 | } |
2787 | ||
ff6657c6 JA |
2788 | if (cic->cfqq[BLK_RW_SYNC]) { |
2789 | cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_SYNC]); | |
2790 | cic->cfqq[BLK_RW_SYNC] = NULL; | |
12a05732 | 2791 | } |
89850f7e JA |
2792 | } |
2793 | ||
4ac845a2 JA |
2794 | static void cfq_exit_single_io_context(struct io_context *ioc, |
2795 | struct cfq_io_context *cic) | |
89850f7e | 2796 | { |
bca4b914 | 2797 | struct cfq_data *cfqd = cic_to_cfqd(cic); |
89850f7e | 2798 | |
89850f7e | 2799 | if (cfqd) { |
165125e1 | 2800 | struct request_queue *q = cfqd->queue; |
4ac845a2 | 2801 | unsigned long flags; |
89850f7e | 2802 | |
4ac845a2 | 2803 | spin_lock_irqsave(q->queue_lock, flags); |
62c1fe9d JA |
2804 | |
2805 | /* | |
2806 | * Ensure we get a fresh copy of the ->key to prevent | |
2807 | * race between exiting task and queue | |
2808 | */ | |
2809 | smp_read_barrier_depends(); | |
bca4b914 | 2810 | if (cic->key == cfqd) |
62c1fe9d JA |
2811 | __cfq_exit_single_io_context(cfqd, cic); |
2812 | ||
4ac845a2 | 2813 | spin_unlock_irqrestore(q->queue_lock, flags); |
89850f7e | 2814 | } |
1da177e4 LT |
2815 | } |
2816 | ||
498d3aa2 JA |
2817 | /* |
2818 | * The process that ioc belongs to has exited, we need to clean up | |
2819 | * and put the internal structures we have that belongs to that process. | |
2820 | */ | |
e2d74ac0 | 2821 | static void cfq_exit_io_context(struct io_context *ioc) |
1da177e4 | 2822 | { |
4ac845a2 | 2823 | call_for_each_cic(ioc, cfq_exit_single_io_context); |
1da177e4 LT |
2824 | } |
2825 | ||
22e2c507 | 2826 | static struct cfq_io_context * |
8267e268 | 2827 | cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
1da177e4 | 2828 | { |
b5deef90 | 2829 | struct cfq_io_context *cic; |
1da177e4 | 2830 | |
94f6030c CL |
2831 | cic = kmem_cache_alloc_node(cfq_ioc_pool, gfp_mask | __GFP_ZERO, |
2832 | cfqd->queue->node); | |
1da177e4 | 2833 | if (cic) { |
22e2c507 | 2834 | cic->last_end_request = jiffies; |
553698f9 | 2835 | INIT_LIST_HEAD(&cic->queue_list); |
ffc4e759 | 2836 | INIT_HLIST_NODE(&cic->cic_list); |
22e2c507 JA |
2837 | cic->dtor = cfq_free_io_context; |
2838 | cic->exit = cfq_exit_io_context; | |
245b2e70 | 2839 | elv_ioc_count_inc(cfq_ioc_count); |
1da177e4 LT |
2840 | } |
2841 | ||
2842 | return cic; | |
2843 | } | |
2844 | ||
fd0928df | 2845 | static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc) |
22e2c507 JA |
2846 | { |
2847 | struct task_struct *tsk = current; | |
2848 | int ioprio_class; | |
2849 | ||
3b18152c | 2850 | if (!cfq_cfqq_prio_changed(cfqq)) |
22e2c507 JA |
2851 | return; |
2852 | ||
fd0928df | 2853 | ioprio_class = IOPRIO_PRIO_CLASS(ioc->ioprio); |
22e2c507 | 2854 | switch (ioprio_class) { |
fe094d98 JA |
2855 | default: |
2856 | printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class); | |
2857 | case IOPRIO_CLASS_NONE: | |
2858 | /* | |
6d63c275 | 2859 | * no prio set, inherit CPU scheduling settings |
fe094d98 JA |
2860 | */ |
2861 | cfqq->ioprio = task_nice_ioprio(tsk); | |
6d63c275 | 2862 | cfqq->ioprio_class = task_nice_ioclass(tsk); |
fe094d98 JA |
2863 | break; |
2864 | case IOPRIO_CLASS_RT: | |
2865 | cfqq->ioprio = task_ioprio(ioc); | |
2866 | cfqq->ioprio_class = IOPRIO_CLASS_RT; | |
2867 | break; | |
2868 | case IOPRIO_CLASS_BE: | |
2869 | cfqq->ioprio = task_ioprio(ioc); | |
2870 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
2871 | break; | |
2872 | case IOPRIO_CLASS_IDLE: | |
2873 | cfqq->ioprio_class = IOPRIO_CLASS_IDLE; | |
2874 | cfqq->ioprio = 7; | |
2875 | cfq_clear_cfqq_idle_window(cfqq); | |
2876 | break; | |
22e2c507 JA |
2877 | } |
2878 | ||
2879 | /* | |
2880 | * keep track of original prio settings in case we have to temporarily | |
2881 | * elevate the priority of this queue | |
2882 | */ | |
2883 | cfqq->org_ioprio = cfqq->ioprio; | |
2884 | cfqq->org_ioprio_class = cfqq->ioprio_class; | |
3b18152c | 2885 | cfq_clear_cfqq_prio_changed(cfqq); |
22e2c507 JA |
2886 | } |
2887 | ||
febffd61 | 2888 | static void changed_ioprio(struct io_context *ioc, struct cfq_io_context *cic) |
22e2c507 | 2889 | { |
bca4b914 | 2890 | struct cfq_data *cfqd = cic_to_cfqd(cic); |
478a82b0 | 2891 | struct cfq_queue *cfqq; |
c1b707d2 | 2892 | unsigned long flags; |
35e6077c | 2893 | |
caaa5f9f JA |
2894 | if (unlikely(!cfqd)) |
2895 | return; | |
2896 | ||
c1b707d2 | 2897 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); |
caaa5f9f | 2898 | |
ff6657c6 | 2899 | cfqq = cic->cfqq[BLK_RW_ASYNC]; |
caaa5f9f JA |
2900 | if (cfqq) { |
2901 | struct cfq_queue *new_cfqq; | |
ff6657c6 JA |
2902 | new_cfqq = cfq_get_queue(cfqd, BLK_RW_ASYNC, cic->ioc, |
2903 | GFP_ATOMIC); | |
caaa5f9f | 2904 | if (new_cfqq) { |
ff6657c6 | 2905 | cic->cfqq[BLK_RW_ASYNC] = new_cfqq; |
caaa5f9f JA |
2906 | cfq_put_queue(cfqq); |
2907 | } | |
22e2c507 | 2908 | } |
caaa5f9f | 2909 | |
ff6657c6 | 2910 | cfqq = cic->cfqq[BLK_RW_SYNC]; |
caaa5f9f JA |
2911 | if (cfqq) |
2912 | cfq_mark_cfqq_prio_changed(cfqq); | |
2913 | ||
c1b707d2 | 2914 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); |
22e2c507 JA |
2915 | } |
2916 | ||
fc46379d | 2917 | static void cfq_ioc_set_ioprio(struct io_context *ioc) |
22e2c507 | 2918 | { |
4ac845a2 | 2919 | call_for_each_cic(ioc, changed_ioprio); |
fc46379d | 2920 | ioc->ioprio_changed = 0; |
22e2c507 JA |
2921 | } |
2922 | ||
d5036d77 | 2923 | static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
a6151c3a | 2924 | pid_t pid, bool is_sync) |
d5036d77 JA |
2925 | { |
2926 | RB_CLEAR_NODE(&cfqq->rb_node); | |
2927 | RB_CLEAR_NODE(&cfqq->p_node); | |
2928 | INIT_LIST_HEAD(&cfqq->fifo); | |
2929 | ||
30d7b944 | 2930 | cfqq->ref = 0; |
d5036d77 JA |
2931 | cfqq->cfqd = cfqd; |
2932 | ||
2933 | cfq_mark_cfqq_prio_changed(cfqq); | |
2934 | ||
2935 | if (is_sync) { | |
2936 | if (!cfq_class_idle(cfqq)) | |
2937 | cfq_mark_cfqq_idle_window(cfqq); | |
2938 | cfq_mark_cfqq_sync(cfqq); | |
2939 | } | |
2940 | cfqq->pid = pid; | |
2941 | } | |
2942 | ||
24610333 VG |
2943 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
2944 | static void changed_cgroup(struct io_context *ioc, struct cfq_io_context *cic) | |
2945 | { | |
2946 | struct cfq_queue *sync_cfqq = cic_to_cfqq(cic, 1); | |
bca4b914 | 2947 | struct cfq_data *cfqd = cic_to_cfqd(cic); |
24610333 VG |
2948 | unsigned long flags; |
2949 | struct request_queue *q; | |
2950 | ||
2951 | if (unlikely(!cfqd)) | |
2952 | return; | |
2953 | ||
2954 | q = cfqd->queue; | |
2955 | ||
2956 | spin_lock_irqsave(q->queue_lock, flags); | |
2957 | ||
2958 | if (sync_cfqq) { | |
2959 | /* | |
2960 | * Drop reference to sync queue. A new sync queue will be | |
2961 | * assigned in new group upon arrival of a fresh request. | |
2962 | */ | |
2963 | cfq_log_cfqq(cfqd, sync_cfqq, "changed cgroup"); | |
2964 | cic_set_cfqq(cic, NULL, 1); | |
2965 | cfq_put_queue(sync_cfqq); | |
2966 | } | |
2967 | ||
2968 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2969 | } | |
2970 | ||
2971 | static void cfq_ioc_set_cgroup(struct io_context *ioc) | |
2972 | { | |
2973 | call_for_each_cic(ioc, changed_cgroup); | |
2974 | ioc->cgroup_changed = 0; | |
2975 | } | |
2976 | #endif /* CONFIG_CFQ_GROUP_IOSCHED */ | |
2977 | ||
22e2c507 | 2978 | static struct cfq_queue * |
a6151c3a | 2979 | cfq_find_alloc_queue(struct cfq_data *cfqd, bool is_sync, |
fd0928df | 2980 | struct io_context *ioc, gfp_t gfp_mask) |
22e2c507 | 2981 | { |
22e2c507 | 2982 | struct cfq_queue *cfqq, *new_cfqq = NULL; |
91fac317 | 2983 | struct cfq_io_context *cic; |
cdb16e8f | 2984 | struct cfq_group *cfqg; |
22e2c507 JA |
2985 | |
2986 | retry: | |
3e59cf9d | 2987 | cfqg = cfq_get_cfqg(cfqd); |
4ac845a2 | 2988 | cic = cfq_cic_lookup(cfqd, ioc); |
91fac317 VT |
2989 | /* cic always exists here */ |
2990 | cfqq = cic_to_cfqq(cic, is_sync); | |
22e2c507 | 2991 | |
6118b70b JA |
2992 | /* |
2993 | * Always try a new alloc if we fell back to the OOM cfqq | |
2994 | * originally, since it should just be a temporary situation. | |
2995 | */ | |
2996 | if (!cfqq || cfqq == &cfqd->oom_cfqq) { | |
2997 | cfqq = NULL; | |
22e2c507 JA |
2998 | if (new_cfqq) { |
2999 | cfqq = new_cfqq; | |
3000 | new_cfqq = NULL; | |
3001 | } else if (gfp_mask & __GFP_WAIT) { | |
3002 | spin_unlock_irq(cfqd->queue->queue_lock); | |
94f6030c | 3003 | new_cfqq = kmem_cache_alloc_node(cfq_pool, |
6118b70b | 3004 | gfp_mask | __GFP_ZERO, |
94f6030c | 3005 | cfqd->queue->node); |
22e2c507 | 3006 | spin_lock_irq(cfqd->queue->queue_lock); |
6118b70b JA |
3007 | if (new_cfqq) |
3008 | goto retry; | |
22e2c507 | 3009 | } else { |
94f6030c CL |
3010 | cfqq = kmem_cache_alloc_node(cfq_pool, |
3011 | gfp_mask | __GFP_ZERO, | |
3012 | cfqd->queue->node); | |
22e2c507 JA |
3013 | } |
3014 | ||
6118b70b JA |
3015 | if (cfqq) { |
3016 | cfq_init_cfqq(cfqd, cfqq, current->pid, is_sync); | |
3017 | cfq_init_prio_data(cfqq, ioc); | |
cdb16e8f | 3018 | cfq_link_cfqq_cfqg(cfqq, cfqg); |
6118b70b JA |
3019 | cfq_log_cfqq(cfqd, cfqq, "alloced"); |
3020 | } else | |
3021 | cfqq = &cfqd->oom_cfqq; | |
22e2c507 JA |
3022 | } |
3023 | ||
3024 | if (new_cfqq) | |
3025 | kmem_cache_free(cfq_pool, new_cfqq); | |
3026 | ||
22e2c507 JA |
3027 | return cfqq; |
3028 | } | |
3029 | ||
c2dea2d1 VT |
3030 | static struct cfq_queue ** |
3031 | cfq_async_queue_prio(struct cfq_data *cfqd, int ioprio_class, int ioprio) | |
3032 | { | |
fe094d98 | 3033 | switch (ioprio_class) { |
c2dea2d1 VT |
3034 | case IOPRIO_CLASS_RT: |
3035 | return &cfqd->async_cfqq[0][ioprio]; | |
3036 | case IOPRIO_CLASS_BE: | |
3037 | return &cfqd->async_cfqq[1][ioprio]; | |
3038 | case IOPRIO_CLASS_IDLE: | |
3039 | return &cfqd->async_idle_cfqq; | |
3040 | default: | |
3041 | BUG(); | |
3042 | } | |
3043 | } | |
3044 | ||
15c31be4 | 3045 | static struct cfq_queue * |
a6151c3a | 3046 | cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct io_context *ioc, |
15c31be4 JA |
3047 | gfp_t gfp_mask) |
3048 | { | |
fd0928df JA |
3049 | const int ioprio = task_ioprio(ioc); |
3050 | const int ioprio_class = task_ioprio_class(ioc); | |
c2dea2d1 | 3051 | struct cfq_queue **async_cfqq = NULL; |
15c31be4 JA |
3052 | struct cfq_queue *cfqq = NULL; |
3053 | ||
c2dea2d1 VT |
3054 | if (!is_sync) { |
3055 | async_cfqq = cfq_async_queue_prio(cfqd, ioprio_class, ioprio); | |
3056 | cfqq = *async_cfqq; | |
3057 | } | |
3058 | ||
6118b70b | 3059 | if (!cfqq) |
fd0928df | 3060 | cfqq = cfq_find_alloc_queue(cfqd, is_sync, ioc, gfp_mask); |
15c31be4 JA |
3061 | |
3062 | /* | |
3063 | * pin the queue now that it's allocated, scheduler exit will prune it | |
3064 | */ | |
c2dea2d1 | 3065 | if (!is_sync && !(*async_cfqq)) { |
30d7b944 | 3066 | cfqq->ref++; |
c2dea2d1 | 3067 | *async_cfqq = cfqq; |
15c31be4 JA |
3068 | } |
3069 | ||
30d7b944 | 3070 | cfqq->ref++; |
15c31be4 JA |
3071 | return cfqq; |
3072 | } | |
3073 | ||
498d3aa2 JA |
3074 | /* |
3075 | * We drop cfq io contexts lazily, so we may find a dead one. | |
3076 | */ | |
dbecf3ab | 3077 | static void |
4ac845a2 JA |
3078 | cfq_drop_dead_cic(struct cfq_data *cfqd, struct io_context *ioc, |
3079 | struct cfq_io_context *cic) | |
dbecf3ab | 3080 | { |
4ac845a2 JA |
3081 | unsigned long flags; |
3082 | ||
fc46379d | 3083 | WARN_ON(!list_empty(&cic->queue_list)); |
bca4b914 | 3084 | BUG_ON(cic->key != cfqd_dead_key(cfqd)); |
597bc485 | 3085 | |
4ac845a2 JA |
3086 | spin_lock_irqsave(&ioc->lock, flags); |
3087 | ||
4faa3c81 | 3088 | BUG_ON(ioc->ioc_data == cic); |
597bc485 | 3089 | |
80b15c73 | 3090 | radix_tree_delete(&ioc->radix_root, cfqd->cic_index); |
ffc4e759 | 3091 | hlist_del_rcu(&cic->cic_list); |
4ac845a2 JA |
3092 | spin_unlock_irqrestore(&ioc->lock, flags); |
3093 | ||
3094 | cfq_cic_free(cic); | |
dbecf3ab OH |
3095 | } |
3096 | ||
e2d74ac0 | 3097 | static struct cfq_io_context * |
4ac845a2 | 3098 | cfq_cic_lookup(struct cfq_data *cfqd, struct io_context *ioc) |
e2d74ac0 | 3099 | { |
e2d74ac0 | 3100 | struct cfq_io_context *cic; |
d6de8be7 | 3101 | unsigned long flags; |
e2d74ac0 | 3102 | |
91fac317 VT |
3103 | if (unlikely(!ioc)) |
3104 | return NULL; | |
3105 | ||
d6de8be7 JA |
3106 | rcu_read_lock(); |
3107 | ||
597bc485 JA |
3108 | /* |
3109 | * we maintain a last-hit cache, to avoid browsing over the tree | |
3110 | */ | |
4ac845a2 | 3111 | cic = rcu_dereference(ioc->ioc_data); |
d6de8be7 JA |
3112 | if (cic && cic->key == cfqd) { |
3113 | rcu_read_unlock(); | |
597bc485 | 3114 | return cic; |
d6de8be7 | 3115 | } |
597bc485 | 3116 | |
4ac845a2 | 3117 | do { |
80b15c73 | 3118 | cic = radix_tree_lookup(&ioc->radix_root, cfqd->cic_index); |
4ac845a2 JA |
3119 | rcu_read_unlock(); |
3120 | if (!cic) | |
3121 | break; | |
bca4b914 | 3122 | if (unlikely(cic->key != cfqd)) { |
4ac845a2 | 3123 | cfq_drop_dead_cic(cfqd, ioc, cic); |
d6de8be7 | 3124 | rcu_read_lock(); |
4ac845a2 | 3125 | continue; |
dbecf3ab | 3126 | } |
e2d74ac0 | 3127 | |
d6de8be7 | 3128 | spin_lock_irqsave(&ioc->lock, flags); |
4ac845a2 | 3129 | rcu_assign_pointer(ioc->ioc_data, cic); |
d6de8be7 | 3130 | spin_unlock_irqrestore(&ioc->lock, flags); |
4ac845a2 JA |
3131 | break; |
3132 | } while (1); | |
e2d74ac0 | 3133 | |
4ac845a2 | 3134 | return cic; |
e2d74ac0 JA |
3135 | } |
3136 | ||
4ac845a2 JA |
3137 | /* |
3138 | * Add cic into ioc, using cfqd as the search key. This enables us to lookup | |
3139 | * the process specific cfq io context when entered from the block layer. | |
3140 | * Also adds the cic to a per-cfqd list, used when this queue is removed. | |
3141 | */ | |
febffd61 JA |
3142 | static int cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc, |
3143 | struct cfq_io_context *cic, gfp_t gfp_mask) | |
e2d74ac0 | 3144 | { |
0261d688 | 3145 | unsigned long flags; |
4ac845a2 | 3146 | int ret; |
e2d74ac0 | 3147 | |
4ac845a2 JA |
3148 | ret = radix_tree_preload(gfp_mask); |
3149 | if (!ret) { | |
3150 | cic->ioc = ioc; | |
3151 | cic->key = cfqd; | |
e2d74ac0 | 3152 | |
4ac845a2 JA |
3153 | spin_lock_irqsave(&ioc->lock, flags); |
3154 | ret = radix_tree_insert(&ioc->radix_root, | |
80b15c73 | 3155 | cfqd->cic_index, cic); |
ffc4e759 JA |
3156 | if (!ret) |
3157 | hlist_add_head_rcu(&cic->cic_list, &ioc->cic_list); | |
4ac845a2 | 3158 | spin_unlock_irqrestore(&ioc->lock, flags); |
e2d74ac0 | 3159 | |
4ac845a2 JA |
3160 | radix_tree_preload_end(); |
3161 | ||
3162 | if (!ret) { | |
3163 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
3164 | list_add(&cic->queue_list, &cfqd->cic_list); | |
3165 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
3166 | } | |
e2d74ac0 JA |
3167 | } |
3168 | ||
4ac845a2 JA |
3169 | if (ret) |
3170 | printk(KERN_ERR "cfq: cic link failed!\n"); | |
fc46379d | 3171 | |
4ac845a2 | 3172 | return ret; |
e2d74ac0 JA |
3173 | } |
3174 | ||
1da177e4 LT |
3175 | /* |
3176 | * Setup general io context and cfq io context. There can be several cfq | |
3177 | * io contexts per general io context, if this process is doing io to more | |
e2d74ac0 | 3178 | * than one device managed by cfq. |
1da177e4 LT |
3179 | */ |
3180 | static struct cfq_io_context * | |
e2d74ac0 | 3181 | cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
1da177e4 | 3182 | { |
22e2c507 | 3183 | struct io_context *ioc = NULL; |
1da177e4 | 3184 | struct cfq_io_context *cic; |
1da177e4 | 3185 | |
22e2c507 | 3186 | might_sleep_if(gfp_mask & __GFP_WAIT); |
1da177e4 | 3187 | |
b5deef90 | 3188 | ioc = get_io_context(gfp_mask, cfqd->queue->node); |
1da177e4 LT |
3189 | if (!ioc) |
3190 | return NULL; | |
3191 | ||
4ac845a2 | 3192 | cic = cfq_cic_lookup(cfqd, ioc); |
e2d74ac0 JA |
3193 | if (cic) |
3194 | goto out; | |
1da177e4 | 3195 | |
e2d74ac0 JA |
3196 | cic = cfq_alloc_io_context(cfqd, gfp_mask); |
3197 | if (cic == NULL) | |
3198 | goto err; | |
1da177e4 | 3199 | |
4ac845a2 JA |
3200 | if (cfq_cic_link(cfqd, ioc, cic, gfp_mask)) |
3201 | goto err_free; | |
3202 | ||
1da177e4 | 3203 | out: |
fc46379d JA |
3204 | smp_read_barrier_depends(); |
3205 | if (unlikely(ioc->ioprio_changed)) | |
3206 | cfq_ioc_set_ioprio(ioc); | |
3207 | ||
24610333 VG |
3208 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
3209 | if (unlikely(ioc->cgroup_changed)) | |
3210 | cfq_ioc_set_cgroup(ioc); | |
3211 | #endif | |
1da177e4 | 3212 | return cic; |
4ac845a2 JA |
3213 | err_free: |
3214 | cfq_cic_free(cic); | |
1da177e4 LT |
3215 | err: |
3216 | put_io_context(ioc); | |
3217 | return NULL; | |
3218 | } | |
3219 | ||
22e2c507 JA |
3220 | static void |
3221 | cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic) | |
1da177e4 | 3222 | { |
aaf1228d JA |
3223 | unsigned long elapsed = jiffies - cic->last_end_request; |
3224 | unsigned long ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle); | |
db3b5848 | 3225 | |
22e2c507 JA |
3226 | cic->ttime_samples = (7*cic->ttime_samples + 256) / 8; |
3227 | cic->ttime_total = (7*cic->ttime_total + 256*ttime) / 8; | |
3228 | cic->ttime_mean = (cic->ttime_total + 128) / cic->ttime_samples; | |
3229 | } | |
1da177e4 | 3230 | |
206dc69b | 3231 | static void |
b2c18e1e | 3232 | cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
6d048f53 | 3233 | struct request *rq) |
206dc69b | 3234 | { |
3dde36dd | 3235 | sector_t sdist = 0; |
41647e7a | 3236 | sector_t n_sec = blk_rq_sectors(rq); |
3dde36dd CZ |
3237 | if (cfqq->last_request_pos) { |
3238 | if (cfqq->last_request_pos < blk_rq_pos(rq)) | |
3239 | sdist = blk_rq_pos(rq) - cfqq->last_request_pos; | |
3240 | else | |
3241 | sdist = cfqq->last_request_pos - blk_rq_pos(rq); | |
3242 | } | |
206dc69b | 3243 | |
3dde36dd | 3244 | cfqq->seek_history <<= 1; |
41647e7a CZ |
3245 | if (blk_queue_nonrot(cfqd->queue)) |
3246 | cfqq->seek_history |= (n_sec < CFQQ_SECT_THR_NONROT); | |
3247 | else | |
3248 | cfqq->seek_history |= (sdist > CFQQ_SEEK_THR); | |
206dc69b | 3249 | } |
1da177e4 | 3250 | |
22e2c507 JA |
3251 | /* |
3252 | * Disable idle window if the process thinks too long or seeks so much that | |
3253 | * it doesn't matter | |
3254 | */ | |
3255 | static void | |
3256 | cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
3257 | struct cfq_io_context *cic) | |
3258 | { | |
7b679138 | 3259 | int old_idle, enable_idle; |
1be92f2f | 3260 | |
0871714e JA |
3261 | /* |
3262 | * Don't idle for async or idle io prio class | |
3263 | */ | |
3264 | if (!cfq_cfqq_sync(cfqq) || cfq_class_idle(cfqq)) | |
1be92f2f JA |
3265 | return; |
3266 | ||
c265a7f4 | 3267 | enable_idle = old_idle = cfq_cfqq_idle_window(cfqq); |
1da177e4 | 3268 | |
76280aff CZ |
3269 | if (cfqq->queued[0] + cfqq->queued[1] >= 4) |
3270 | cfq_mark_cfqq_deep(cfqq); | |
3271 | ||
749ef9f8 CZ |
3272 | if (cfqq->next_rq && (cfqq->next_rq->cmd_flags & REQ_NOIDLE)) |
3273 | enable_idle = 0; | |
3274 | else if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle || | |
3dde36dd | 3275 | (!cfq_cfqq_deep(cfqq) && CFQQ_SEEKY(cfqq))) |
22e2c507 JA |
3276 | enable_idle = 0; |
3277 | else if (sample_valid(cic->ttime_samples)) { | |
718eee05 | 3278 | if (cic->ttime_mean > cfqd->cfq_slice_idle) |
22e2c507 JA |
3279 | enable_idle = 0; |
3280 | else | |
3281 | enable_idle = 1; | |
1da177e4 LT |
3282 | } |
3283 | ||
7b679138 JA |
3284 | if (old_idle != enable_idle) { |
3285 | cfq_log_cfqq(cfqd, cfqq, "idle=%d", enable_idle); | |
3286 | if (enable_idle) | |
3287 | cfq_mark_cfqq_idle_window(cfqq); | |
3288 | else | |
3289 | cfq_clear_cfqq_idle_window(cfqq); | |
3290 | } | |
22e2c507 | 3291 | } |
1da177e4 | 3292 | |
22e2c507 JA |
3293 | /* |
3294 | * Check if new_cfqq should preempt the currently active queue. Return 0 for | |
3295 | * no or if we aren't sure, a 1 will cause a preempt. | |
3296 | */ | |
a6151c3a | 3297 | static bool |
22e2c507 | 3298 | cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, |
5e705374 | 3299 | struct request *rq) |
22e2c507 | 3300 | { |
6d048f53 | 3301 | struct cfq_queue *cfqq; |
22e2c507 | 3302 | |
6d048f53 JA |
3303 | cfqq = cfqd->active_queue; |
3304 | if (!cfqq) | |
a6151c3a | 3305 | return false; |
22e2c507 | 3306 | |
6d048f53 | 3307 | if (cfq_class_idle(new_cfqq)) |
a6151c3a | 3308 | return false; |
22e2c507 JA |
3309 | |
3310 | if (cfq_class_idle(cfqq)) | |
a6151c3a | 3311 | return true; |
1e3335de | 3312 | |
875feb63 DS |
3313 | /* |
3314 | * Don't allow a non-RT request to preempt an ongoing RT cfqq timeslice. | |
3315 | */ | |
3316 | if (cfq_class_rt(cfqq) && !cfq_class_rt(new_cfqq)) | |
3317 | return false; | |
3318 | ||
374f84ac JA |
3319 | /* |
3320 | * if the new request is sync, but the currently running queue is | |
3321 | * not, let the sync request have priority. | |
3322 | */ | |
5e705374 | 3323 | if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq)) |
a6151c3a | 3324 | return true; |
1e3335de | 3325 | |
8682e1f1 VG |
3326 | if (new_cfqq->cfqg != cfqq->cfqg) |
3327 | return false; | |
3328 | ||
3329 | if (cfq_slice_used(cfqq)) | |
3330 | return true; | |
3331 | ||
3332 | /* Allow preemption only if we are idling on sync-noidle tree */ | |
3333 | if (cfqd->serving_type == SYNC_NOIDLE_WORKLOAD && | |
3334 | cfqq_type(new_cfqq) == SYNC_NOIDLE_WORKLOAD && | |
3335 | new_cfqq->service_tree->count == 2 && | |
3336 | RB_EMPTY_ROOT(&cfqq->sort_list)) | |
3337 | return true; | |
3338 | ||
374f84ac JA |
3339 | /* |
3340 | * So both queues are sync. Let the new request get disk time if | |
3341 | * it's a metadata request and the current queue is doing regular IO. | |
3342 | */ | |
7b6d91da | 3343 | if ((rq->cmd_flags & REQ_META) && !cfqq->meta_pending) |
e6ec4fe2 | 3344 | return true; |
22e2c507 | 3345 | |
3a9a3f6c DS |
3346 | /* |
3347 | * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice. | |
3348 | */ | |
3349 | if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq)) | |
a6151c3a | 3350 | return true; |
3a9a3f6c | 3351 | |
d2d59e18 SL |
3352 | /* An idle queue should not be idle now for some reason */ |
3353 | if (RB_EMPTY_ROOT(&cfqq->sort_list) && !cfq_should_idle(cfqd, cfqq)) | |
3354 | return true; | |
3355 | ||
1e3335de | 3356 | if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq)) |
a6151c3a | 3357 | return false; |
1e3335de JA |
3358 | |
3359 | /* | |
3360 | * if this request is as-good as one we would expect from the | |
3361 | * current cfqq, let it preempt | |
3362 | */ | |
e9ce335d | 3363 | if (cfq_rq_close(cfqd, cfqq, rq)) |
a6151c3a | 3364 | return true; |
1e3335de | 3365 | |
a6151c3a | 3366 | return false; |
22e2c507 JA |
3367 | } |
3368 | ||
3369 | /* | |
3370 | * cfqq preempts the active queue. if we allowed preempt with no slice left, | |
3371 | * let it have half of its nominal slice. | |
3372 | */ | |
3373 | static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
3374 | { | |
f8ae6e3e SL |
3375 | struct cfq_queue *old_cfqq = cfqd->active_queue; |
3376 | ||
7b679138 | 3377 | cfq_log_cfqq(cfqd, cfqq, "preempt"); |
e5ff082e | 3378 | cfq_slice_expired(cfqd, 1); |
22e2c507 | 3379 | |
f8ae6e3e SL |
3380 | /* |
3381 | * workload type is changed, don't save slice, otherwise preempt | |
3382 | * doesn't happen | |
3383 | */ | |
3384 | if (cfqq_type(old_cfqq) != cfqq_type(cfqq)) | |
3385 | cfqq->cfqg->saved_workload_slice = 0; | |
3386 | ||
bf572256 JA |
3387 | /* |
3388 | * Put the new queue at the front of the of the current list, | |
3389 | * so we know that it will be selected next. | |
3390 | */ | |
3391 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); | |
edd75ffd JA |
3392 | |
3393 | cfq_service_tree_add(cfqd, cfqq, 1); | |
eda5e0c9 | 3394 | |
62a37f6b JT |
3395 | cfqq->slice_end = 0; |
3396 | cfq_mark_cfqq_slice_new(cfqq); | |
22e2c507 JA |
3397 | } |
3398 | ||
22e2c507 | 3399 | /* |
5e705374 | 3400 | * Called when a new fs request (rq) is added (to cfqq). Check if there's |
22e2c507 JA |
3401 | * something we should do about it |
3402 | */ | |
3403 | static void | |
5e705374 JA |
3404 | cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
3405 | struct request *rq) | |
22e2c507 | 3406 | { |
5e705374 | 3407 | struct cfq_io_context *cic = RQ_CIC(rq); |
12e9fddd | 3408 | |
45333d5a | 3409 | cfqd->rq_queued++; |
7b6d91da | 3410 | if (rq->cmd_flags & REQ_META) |
374f84ac JA |
3411 | cfqq->meta_pending++; |
3412 | ||
9c2c38a1 | 3413 | cfq_update_io_thinktime(cfqd, cic); |
b2c18e1e | 3414 | cfq_update_io_seektime(cfqd, cfqq, rq); |
9c2c38a1 JA |
3415 | cfq_update_idle_window(cfqd, cfqq, cic); |
3416 | ||
b2c18e1e | 3417 | cfqq->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq); |
22e2c507 JA |
3418 | |
3419 | if (cfqq == cfqd->active_queue) { | |
3420 | /* | |
b029195d JA |
3421 | * Remember that we saw a request from this process, but |
3422 | * don't start queuing just yet. Otherwise we risk seeing lots | |
3423 | * of tiny requests, because we disrupt the normal plugging | |
d6ceb25e JA |
3424 | * and merging. If the request is already larger than a single |
3425 | * page, let it rip immediately. For that case we assume that | |
2d870722 JA |
3426 | * merging is already done. Ditto for a busy system that |
3427 | * has other work pending, don't risk delaying until the | |
3428 | * idle timer unplug to continue working. | |
22e2c507 | 3429 | */ |
d6ceb25e | 3430 | if (cfq_cfqq_wait_request(cfqq)) { |
2d870722 JA |
3431 | if (blk_rq_bytes(rq) > PAGE_CACHE_SIZE || |
3432 | cfqd->busy_queues > 1) { | |
812df48d | 3433 | cfq_del_timer(cfqd, cfqq); |
554554f6 | 3434 | cfq_clear_cfqq_wait_request(cfqq); |
24ecfbe2 | 3435 | __blk_run_queue(cfqd->queue); |
a11cdaa7 | 3436 | } else { |
e98ef89b | 3437 | cfq_blkiocg_update_idle_time_stats( |
a11cdaa7 | 3438 | &cfqq->cfqg->blkg); |
bf791937 | 3439 | cfq_mark_cfqq_must_dispatch(cfqq); |
a11cdaa7 | 3440 | } |
d6ceb25e | 3441 | } |
5e705374 | 3442 | } else if (cfq_should_preempt(cfqd, cfqq, rq)) { |
22e2c507 JA |
3443 | /* |
3444 | * not the active queue - expire current slice if it is | |
3445 | * idle and has expired it's mean thinktime or this new queue | |
3a9a3f6c DS |
3446 | * has some old slice time left and is of higher priority or |
3447 | * this new queue is RT and the current one is BE | |
22e2c507 JA |
3448 | */ |
3449 | cfq_preempt_queue(cfqd, cfqq); | |
24ecfbe2 | 3450 | __blk_run_queue(cfqd->queue); |
22e2c507 | 3451 | } |
1da177e4 LT |
3452 | } |
3453 | ||
165125e1 | 3454 | static void cfq_insert_request(struct request_queue *q, struct request *rq) |
1da177e4 | 3455 | { |
b4878f24 | 3456 | struct cfq_data *cfqd = q->elevator->elevator_data; |
5e705374 | 3457 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 | 3458 | |
7b679138 | 3459 | cfq_log_cfqq(cfqd, cfqq, "insert_request"); |
fd0928df | 3460 | cfq_init_prio_data(cfqq, RQ_CIC(rq)->ioc); |
1da177e4 | 3461 | |
30996f40 | 3462 | rq_set_fifo_time(rq, jiffies + cfqd->cfq_fifo_expire[rq_is_sync(rq)]); |
22e2c507 | 3463 | list_add_tail(&rq->queuelist, &cfqq->fifo); |
aa6f6a3d | 3464 | cfq_add_rq_rb(rq); |
e98ef89b | 3465 | cfq_blkiocg_update_io_add_stats(&(RQ_CFQG(rq))->blkg, |
cdc1184c DS |
3466 | &cfqd->serving_group->blkg, rq_data_dir(rq), |
3467 | rq_is_sync(rq)); | |
5e705374 | 3468 | cfq_rq_enqueued(cfqd, cfqq, rq); |
1da177e4 LT |
3469 | } |
3470 | ||
45333d5a AC |
3471 | /* |
3472 | * Update hw_tag based on peak queue depth over 50 samples under | |
3473 | * sufficient load. | |
3474 | */ | |
3475 | static void cfq_update_hw_tag(struct cfq_data *cfqd) | |
3476 | { | |
1a1238a7 SL |
3477 | struct cfq_queue *cfqq = cfqd->active_queue; |
3478 | ||
53c583d2 CZ |
3479 | if (cfqd->rq_in_driver > cfqd->hw_tag_est_depth) |
3480 | cfqd->hw_tag_est_depth = cfqd->rq_in_driver; | |
e459dd08 CZ |
3481 | |
3482 | if (cfqd->hw_tag == 1) | |
3483 | return; | |
45333d5a AC |
3484 | |
3485 | if (cfqd->rq_queued <= CFQ_HW_QUEUE_MIN && | |
53c583d2 | 3486 | cfqd->rq_in_driver <= CFQ_HW_QUEUE_MIN) |
45333d5a AC |
3487 | return; |
3488 | ||
1a1238a7 SL |
3489 | /* |
3490 | * If active queue hasn't enough requests and can idle, cfq might not | |
3491 | * dispatch sufficient requests to hardware. Don't zero hw_tag in this | |
3492 | * case | |
3493 | */ | |
3494 | if (cfqq && cfq_cfqq_idle_window(cfqq) && | |
3495 | cfqq->dispatched + cfqq->queued[0] + cfqq->queued[1] < | |
53c583d2 | 3496 | CFQ_HW_QUEUE_MIN && cfqd->rq_in_driver < CFQ_HW_QUEUE_MIN) |
1a1238a7 SL |
3497 | return; |
3498 | ||
45333d5a AC |
3499 | if (cfqd->hw_tag_samples++ < 50) |
3500 | return; | |
3501 | ||
e459dd08 | 3502 | if (cfqd->hw_tag_est_depth >= CFQ_HW_QUEUE_MIN) |
45333d5a AC |
3503 | cfqd->hw_tag = 1; |
3504 | else | |
3505 | cfqd->hw_tag = 0; | |
45333d5a AC |
3506 | } |
3507 | ||
7667aa06 VG |
3508 | static bool cfq_should_wait_busy(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
3509 | { | |
3510 | struct cfq_io_context *cic = cfqd->active_cic; | |
3511 | ||
02a8f01b JT |
3512 | /* If the queue already has requests, don't wait */ |
3513 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) | |
3514 | return false; | |
3515 | ||
7667aa06 VG |
3516 | /* If there are other queues in the group, don't wait */ |
3517 | if (cfqq->cfqg->nr_cfqq > 1) | |
3518 | return false; | |
3519 | ||
3520 | if (cfq_slice_used(cfqq)) | |
3521 | return true; | |
3522 | ||
3523 | /* if slice left is less than think time, wait busy */ | |
3524 | if (cic && sample_valid(cic->ttime_samples) | |
3525 | && (cfqq->slice_end - jiffies < cic->ttime_mean)) | |
3526 | return true; | |
3527 | ||
3528 | /* | |
3529 | * If think times is less than a jiffy than ttime_mean=0 and above | |
3530 | * will not be true. It might happen that slice has not expired yet | |
3531 | * but will expire soon (4-5 ns) during select_queue(). To cover the | |
3532 | * case where think time is less than a jiffy, mark the queue wait | |
3533 | * busy if only 1 jiffy is left in the slice. | |
3534 | */ | |
3535 | if (cfqq->slice_end - jiffies == 1) | |
3536 | return true; | |
3537 | ||
3538 | return false; | |
3539 | } | |
3540 | ||
165125e1 | 3541 | static void cfq_completed_request(struct request_queue *q, struct request *rq) |
1da177e4 | 3542 | { |
5e705374 | 3543 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
b4878f24 | 3544 | struct cfq_data *cfqd = cfqq->cfqd; |
5380a101 | 3545 | const int sync = rq_is_sync(rq); |
b4878f24 | 3546 | unsigned long now; |
1da177e4 | 3547 | |
b4878f24 | 3548 | now = jiffies; |
33659ebb CH |
3549 | cfq_log_cfqq(cfqd, cfqq, "complete rqnoidle %d", |
3550 | !!(rq->cmd_flags & REQ_NOIDLE)); | |
1da177e4 | 3551 | |
45333d5a AC |
3552 | cfq_update_hw_tag(cfqd); |
3553 | ||
53c583d2 | 3554 | WARN_ON(!cfqd->rq_in_driver); |
6d048f53 | 3555 | WARN_ON(!cfqq->dispatched); |
53c583d2 | 3556 | cfqd->rq_in_driver--; |
6d048f53 | 3557 | cfqq->dispatched--; |
80bdf0c7 | 3558 | (RQ_CFQG(rq))->dispatched--; |
e98ef89b VG |
3559 | cfq_blkiocg_update_completion_stats(&cfqq->cfqg->blkg, |
3560 | rq_start_time_ns(rq), rq_io_start_time_ns(rq), | |
3561 | rq_data_dir(rq), rq_is_sync(rq)); | |
1da177e4 | 3562 | |
53c583d2 | 3563 | cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]--; |
3ed9a296 | 3564 | |
365722bb | 3565 | if (sync) { |
5e705374 | 3566 | RQ_CIC(rq)->last_end_request = now; |
573412b2 CZ |
3567 | if (!time_after(rq->start_time + cfqd->cfq_fifo_expire[1], now)) |
3568 | cfqd->last_delayed_sync = now; | |
365722bb | 3569 | } |
caaa5f9f JA |
3570 | |
3571 | /* | |
3572 | * If this is the active queue, check if it needs to be expired, | |
3573 | * or if we want to idle in case it has no pending requests. | |
3574 | */ | |
3575 | if (cfqd->active_queue == cfqq) { | |
a36e71f9 JA |
3576 | const bool cfqq_empty = RB_EMPTY_ROOT(&cfqq->sort_list); |
3577 | ||
44f7c160 JA |
3578 | if (cfq_cfqq_slice_new(cfqq)) { |
3579 | cfq_set_prio_slice(cfqd, cfqq); | |
3580 | cfq_clear_cfqq_slice_new(cfqq); | |
3581 | } | |
f75edf2d VG |
3582 | |
3583 | /* | |
7667aa06 VG |
3584 | * Should we wait for next request to come in before we expire |
3585 | * the queue. | |
f75edf2d | 3586 | */ |
7667aa06 | 3587 | if (cfq_should_wait_busy(cfqd, cfqq)) { |
80bdf0c7 VG |
3588 | unsigned long extend_sl = cfqd->cfq_slice_idle; |
3589 | if (!cfqd->cfq_slice_idle) | |
3590 | extend_sl = cfqd->cfq_group_idle; | |
3591 | cfqq->slice_end = jiffies + extend_sl; | |
f75edf2d | 3592 | cfq_mark_cfqq_wait_busy(cfqq); |
b1ffe737 | 3593 | cfq_log_cfqq(cfqd, cfqq, "will busy wait"); |
f75edf2d VG |
3594 | } |
3595 | ||
a36e71f9 | 3596 | /* |
8e550632 CZ |
3597 | * Idling is not enabled on: |
3598 | * - expired queues | |
3599 | * - idle-priority queues | |
3600 | * - async queues | |
3601 | * - queues with still some requests queued | |
3602 | * - when there is a close cooperator | |
a36e71f9 | 3603 | */ |
0871714e | 3604 | if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq)) |
e5ff082e | 3605 | cfq_slice_expired(cfqd, 1); |
8e550632 CZ |
3606 | else if (sync && cfqq_empty && |
3607 | !cfq_close_cooperator(cfqd, cfqq)) { | |
749ef9f8 | 3608 | cfq_arm_slice_timer(cfqd); |
8e550632 | 3609 | } |
caaa5f9f | 3610 | } |
6d048f53 | 3611 | |
53c583d2 | 3612 | if (!cfqd->rq_in_driver) |
23e018a1 | 3613 | cfq_schedule_dispatch(cfqd); |
1da177e4 LT |
3614 | } |
3615 | ||
22e2c507 JA |
3616 | /* |
3617 | * we temporarily boost lower priority queues if they are holding fs exclusive | |
3618 | * resources. they are boosted to normal prio (CLASS_BE/4) | |
3619 | */ | |
3620 | static void cfq_prio_boost(struct cfq_queue *cfqq) | |
1da177e4 | 3621 | { |
22e2c507 JA |
3622 | if (has_fs_excl()) { |
3623 | /* | |
3624 | * boost idle prio on transactions that would lock out other | |
3625 | * users of the filesystem | |
3626 | */ | |
3627 | if (cfq_class_idle(cfqq)) | |
3628 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
3629 | if (cfqq->ioprio > IOPRIO_NORM) | |
3630 | cfqq->ioprio = IOPRIO_NORM; | |
3631 | } else { | |
3632 | /* | |
dddb7451 | 3633 | * unboost the queue (if needed) |
22e2c507 | 3634 | */ |
dddb7451 CZ |
3635 | cfqq->ioprio_class = cfqq->org_ioprio_class; |
3636 | cfqq->ioprio = cfqq->org_ioprio; | |
22e2c507 | 3637 | } |
22e2c507 | 3638 | } |
1da177e4 | 3639 | |
89850f7e | 3640 | static inline int __cfq_may_queue(struct cfq_queue *cfqq) |
22e2c507 | 3641 | { |
1b379d8d | 3642 | if (cfq_cfqq_wait_request(cfqq) && !cfq_cfqq_must_alloc_slice(cfqq)) { |
3b18152c | 3643 | cfq_mark_cfqq_must_alloc_slice(cfqq); |
22e2c507 | 3644 | return ELV_MQUEUE_MUST; |
3b18152c | 3645 | } |
1da177e4 | 3646 | |
22e2c507 | 3647 | return ELV_MQUEUE_MAY; |
22e2c507 JA |
3648 | } |
3649 | ||
165125e1 | 3650 | static int cfq_may_queue(struct request_queue *q, int rw) |
22e2c507 JA |
3651 | { |
3652 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
3653 | struct task_struct *tsk = current; | |
91fac317 | 3654 | struct cfq_io_context *cic; |
22e2c507 JA |
3655 | struct cfq_queue *cfqq; |
3656 | ||
3657 | /* | |
3658 | * don't force setup of a queue from here, as a call to may_queue | |
3659 | * does not necessarily imply that a request actually will be queued. | |
3660 | * so just lookup a possibly existing queue, or return 'may queue' | |
3661 | * if that fails | |
3662 | */ | |
4ac845a2 | 3663 | cic = cfq_cic_lookup(cfqd, tsk->io_context); |
91fac317 VT |
3664 | if (!cic) |
3665 | return ELV_MQUEUE_MAY; | |
3666 | ||
b0b78f81 | 3667 | cfqq = cic_to_cfqq(cic, rw_is_sync(rw)); |
22e2c507 | 3668 | if (cfqq) { |
fd0928df | 3669 | cfq_init_prio_data(cfqq, cic->ioc); |
22e2c507 JA |
3670 | cfq_prio_boost(cfqq); |
3671 | ||
89850f7e | 3672 | return __cfq_may_queue(cfqq); |
22e2c507 JA |
3673 | } |
3674 | ||
3675 | return ELV_MQUEUE_MAY; | |
1da177e4 LT |
3676 | } |
3677 | ||
1da177e4 LT |
3678 | /* |
3679 | * queue lock held here | |
3680 | */ | |
bb37b94c | 3681 | static void cfq_put_request(struct request *rq) |
1da177e4 | 3682 | { |
5e705374 | 3683 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
1da177e4 | 3684 | |
5e705374 | 3685 | if (cfqq) { |
22e2c507 | 3686 | const int rw = rq_data_dir(rq); |
1da177e4 | 3687 | |
22e2c507 JA |
3688 | BUG_ON(!cfqq->allocated[rw]); |
3689 | cfqq->allocated[rw]--; | |
1da177e4 | 3690 | |
5e705374 | 3691 | put_io_context(RQ_CIC(rq)->ioc); |
1da177e4 | 3692 | |
c186794d MS |
3693 | rq->elevator_private[0] = NULL; |
3694 | rq->elevator_private[1] = NULL; | |
1da177e4 | 3695 | |
7f1dc8a2 VG |
3696 | /* Put down rq reference on cfqg */ |
3697 | cfq_put_cfqg(RQ_CFQG(rq)); | |
c186794d | 3698 | rq->elevator_private[2] = NULL; |
7f1dc8a2 | 3699 | |
1da177e4 LT |
3700 | cfq_put_queue(cfqq); |
3701 | } | |
3702 | } | |
3703 | ||
df5fe3e8 JM |
3704 | static struct cfq_queue * |
3705 | cfq_merge_cfqqs(struct cfq_data *cfqd, struct cfq_io_context *cic, | |
3706 | struct cfq_queue *cfqq) | |
3707 | { | |
3708 | cfq_log_cfqq(cfqd, cfqq, "merging with queue %p", cfqq->new_cfqq); | |
3709 | cic_set_cfqq(cic, cfqq->new_cfqq, 1); | |
b3b6d040 | 3710 | cfq_mark_cfqq_coop(cfqq->new_cfqq); |
df5fe3e8 JM |
3711 | cfq_put_queue(cfqq); |
3712 | return cic_to_cfqq(cic, 1); | |
3713 | } | |
3714 | ||
e6c5bc73 JM |
3715 | /* |
3716 | * Returns NULL if a new cfqq should be allocated, or the old cfqq if this | |
3717 | * was the last process referring to said cfqq. | |
3718 | */ | |
3719 | static struct cfq_queue * | |
3720 | split_cfqq(struct cfq_io_context *cic, struct cfq_queue *cfqq) | |
3721 | { | |
3722 | if (cfqq_process_refs(cfqq) == 1) { | |
e6c5bc73 JM |
3723 | cfqq->pid = current->pid; |
3724 | cfq_clear_cfqq_coop(cfqq); | |
ae54abed | 3725 | cfq_clear_cfqq_split_coop(cfqq); |
e6c5bc73 JM |
3726 | return cfqq; |
3727 | } | |
3728 | ||
3729 | cic_set_cfqq(cic, NULL, 1); | |
d02a2c07 SL |
3730 | |
3731 | cfq_put_cooperator(cfqq); | |
3732 | ||
e6c5bc73 JM |
3733 | cfq_put_queue(cfqq); |
3734 | return NULL; | |
3735 | } | |
1da177e4 | 3736 | /* |
22e2c507 | 3737 | * Allocate cfq data structures associated with this request. |
1da177e4 | 3738 | */ |
22e2c507 | 3739 | static int |
165125e1 | 3740 | cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask) |
1da177e4 LT |
3741 | { |
3742 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
3743 | struct cfq_io_context *cic; | |
3744 | const int rw = rq_data_dir(rq); | |
a6151c3a | 3745 | const bool is_sync = rq_is_sync(rq); |
22e2c507 | 3746 | struct cfq_queue *cfqq; |
1da177e4 LT |
3747 | unsigned long flags; |
3748 | ||
3749 | might_sleep_if(gfp_mask & __GFP_WAIT); | |
3750 | ||
e2d74ac0 | 3751 | cic = cfq_get_io_context(cfqd, gfp_mask); |
22e2c507 | 3752 | |
1da177e4 LT |
3753 | spin_lock_irqsave(q->queue_lock, flags); |
3754 | ||
22e2c507 JA |
3755 | if (!cic) |
3756 | goto queue_fail; | |
3757 | ||
e6c5bc73 | 3758 | new_queue: |
91fac317 | 3759 | cfqq = cic_to_cfqq(cic, is_sync); |
32f2e807 | 3760 | if (!cfqq || cfqq == &cfqd->oom_cfqq) { |
fd0928df | 3761 | cfqq = cfq_get_queue(cfqd, is_sync, cic->ioc, gfp_mask); |
91fac317 | 3762 | cic_set_cfqq(cic, cfqq, is_sync); |
df5fe3e8 | 3763 | } else { |
e6c5bc73 JM |
3764 | /* |
3765 | * If the queue was seeky for too long, break it apart. | |
3766 | */ | |
ae54abed | 3767 | if (cfq_cfqq_coop(cfqq) && cfq_cfqq_split_coop(cfqq)) { |
e6c5bc73 JM |
3768 | cfq_log_cfqq(cfqd, cfqq, "breaking apart cfqq"); |
3769 | cfqq = split_cfqq(cic, cfqq); | |
3770 | if (!cfqq) | |
3771 | goto new_queue; | |
3772 | } | |
3773 | ||
df5fe3e8 JM |
3774 | /* |
3775 | * Check to see if this queue is scheduled to merge with | |
3776 | * another, closely cooperating queue. The merging of | |
3777 | * queues happens here as it must be done in process context. | |
3778 | * The reference on new_cfqq was taken in merge_cfqqs. | |
3779 | */ | |
3780 | if (cfqq->new_cfqq) | |
3781 | cfqq = cfq_merge_cfqqs(cfqd, cic, cfqq); | |
91fac317 | 3782 | } |
1da177e4 LT |
3783 | |
3784 | cfqq->allocated[rw]++; | |
1da177e4 | 3785 | |
6fae9c25 | 3786 | cfqq->ref++; |
c186794d MS |
3787 | rq->elevator_private[0] = cic; |
3788 | rq->elevator_private[1] = cfqq; | |
3789 | rq->elevator_private[2] = cfq_ref_get_cfqg(cfqq->cfqg); | |
93803e01 | 3790 | spin_unlock_irqrestore(q->queue_lock, flags); |
5e705374 | 3791 | return 0; |
1da177e4 | 3792 | |
22e2c507 JA |
3793 | queue_fail: |
3794 | if (cic) | |
3795 | put_io_context(cic->ioc); | |
89850f7e | 3796 | |
23e018a1 | 3797 | cfq_schedule_dispatch(cfqd); |
1da177e4 | 3798 | spin_unlock_irqrestore(q->queue_lock, flags); |
7b679138 | 3799 | cfq_log(cfqd, "set_request fail"); |
1da177e4 LT |
3800 | return 1; |
3801 | } | |
3802 | ||
65f27f38 | 3803 | static void cfq_kick_queue(struct work_struct *work) |
22e2c507 | 3804 | { |
65f27f38 | 3805 | struct cfq_data *cfqd = |
23e018a1 | 3806 | container_of(work, struct cfq_data, unplug_work); |
165125e1 | 3807 | struct request_queue *q = cfqd->queue; |
22e2c507 | 3808 | |
40bb54d1 | 3809 | spin_lock_irq(q->queue_lock); |
24ecfbe2 | 3810 | __blk_run_queue(cfqd->queue); |
40bb54d1 | 3811 | spin_unlock_irq(q->queue_lock); |
22e2c507 JA |
3812 | } |
3813 | ||
3814 | /* | |
3815 | * Timer running if the active_queue is currently idling inside its time slice | |
3816 | */ | |
3817 | static void cfq_idle_slice_timer(unsigned long data) | |
3818 | { | |
3819 | struct cfq_data *cfqd = (struct cfq_data *) data; | |
3820 | struct cfq_queue *cfqq; | |
3821 | unsigned long flags; | |
3c6bd2f8 | 3822 | int timed_out = 1; |
22e2c507 | 3823 | |
7b679138 JA |
3824 | cfq_log(cfqd, "idle timer fired"); |
3825 | ||
22e2c507 JA |
3826 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); |
3827 | ||
fe094d98 JA |
3828 | cfqq = cfqd->active_queue; |
3829 | if (cfqq) { | |
3c6bd2f8 JA |
3830 | timed_out = 0; |
3831 | ||
b029195d JA |
3832 | /* |
3833 | * We saw a request before the queue expired, let it through | |
3834 | */ | |
3835 | if (cfq_cfqq_must_dispatch(cfqq)) | |
3836 | goto out_kick; | |
3837 | ||
22e2c507 JA |
3838 | /* |
3839 | * expired | |
3840 | */ | |
44f7c160 | 3841 | if (cfq_slice_used(cfqq)) |
22e2c507 JA |
3842 | goto expire; |
3843 | ||
3844 | /* | |
3845 | * only expire and reinvoke request handler, if there are | |
3846 | * other queues with pending requests | |
3847 | */ | |
caaa5f9f | 3848 | if (!cfqd->busy_queues) |
22e2c507 | 3849 | goto out_cont; |
22e2c507 JA |
3850 | |
3851 | /* | |
3852 | * not expired and it has a request pending, let it dispatch | |
3853 | */ | |
75e50984 | 3854 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
22e2c507 | 3855 | goto out_kick; |
76280aff CZ |
3856 | |
3857 | /* | |
3858 | * Queue depth flag is reset only when the idle didn't succeed | |
3859 | */ | |
3860 | cfq_clear_cfqq_deep(cfqq); | |
22e2c507 JA |
3861 | } |
3862 | expire: | |
e5ff082e | 3863 | cfq_slice_expired(cfqd, timed_out); |
22e2c507 | 3864 | out_kick: |
23e018a1 | 3865 | cfq_schedule_dispatch(cfqd); |
22e2c507 JA |
3866 | out_cont: |
3867 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
3868 | } | |
3869 | ||
3b18152c JA |
3870 | static void cfq_shutdown_timer_wq(struct cfq_data *cfqd) |
3871 | { | |
3872 | del_timer_sync(&cfqd->idle_slice_timer); | |
23e018a1 | 3873 | cancel_work_sync(&cfqd->unplug_work); |
3b18152c | 3874 | } |
22e2c507 | 3875 | |
c2dea2d1 VT |
3876 | static void cfq_put_async_queues(struct cfq_data *cfqd) |
3877 | { | |
3878 | int i; | |
3879 | ||
3880 | for (i = 0; i < IOPRIO_BE_NR; i++) { | |
3881 | if (cfqd->async_cfqq[0][i]) | |
3882 | cfq_put_queue(cfqd->async_cfqq[0][i]); | |
3883 | if (cfqd->async_cfqq[1][i]) | |
3884 | cfq_put_queue(cfqd->async_cfqq[1][i]); | |
c2dea2d1 | 3885 | } |
2389d1ef ON |
3886 | |
3887 | if (cfqd->async_idle_cfqq) | |
3888 | cfq_put_queue(cfqd->async_idle_cfqq); | |
c2dea2d1 VT |
3889 | } |
3890 | ||
b374d18a | 3891 | static void cfq_exit_queue(struct elevator_queue *e) |
1da177e4 | 3892 | { |
22e2c507 | 3893 | struct cfq_data *cfqd = e->elevator_data; |
165125e1 | 3894 | struct request_queue *q = cfqd->queue; |
56edf7d7 | 3895 | bool wait = false; |
22e2c507 | 3896 | |
3b18152c | 3897 | cfq_shutdown_timer_wq(cfqd); |
e2d74ac0 | 3898 | |
d9ff4187 | 3899 | spin_lock_irq(q->queue_lock); |
e2d74ac0 | 3900 | |
d9ff4187 | 3901 | if (cfqd->active_queue) |
e5ff082e | 3902 | __cfq_slice_expired(cfqd, cfqd->active_queue, 0); |
e2d74ac0 JA |
3903 | |
3904 | while (!list_empty(&cfqd->cic_list)) { | |
d9ff4187 AV |
3905 | struct cfq_io_context *cic = list_entry(cfqd->cic_list.next, |
3906 | struct cfq_io_context, | |
3907 | queue_list); | |
89850f7e JA |
3908 | |
3909 | __cfq_exit_single_io_context(cfqd, cic); | |
d9ff4187 | 3910 | } |
e2d74ac0 | 3911 | |
c2dea2d1 | 3912 | cfq_put_async_queues(cfqd); |
b1c35769 | 3913 | cfq_release_cfq_groups(cfqd); |
56edf7d7 VG |
3914 | |
3915 | /* | |
3916 | * If there are groups which we could not unlink from blkcg list, | |
3917 | * wait for a rcu period for them to be freed. | |
3918 | */ | |
3919 | if (cfqd->nr_blkcg_linked_grps) | |
3920 | wait = true; | |
15c31be4 | 3921 | |
d9ff4187 | 3922 | spin_unlock_irq(q->queue_lock); |
a90d742e AV |
3923 | |
3924 | cfq_shutdown_timer_wq(cfqd); | |
3925 | ||
80b15c73 KK |
3926 | spin_lock(&cic_index_lock); |
3927 | ida_remove(&cic_index_ida, cfqd->cic_index); | |
3928 | spin_unlock(&cic_index_lock); | |
3929 | ||
56edf7d7 VG |
3930 | /* |
3931 | * Wait for cfqg->blkg->key accessors to exit their grace periods. | |
3932 | * Do this wait only if there are other unlinked groups out | |
3933 | * there. This can happen if cgroup deletion path claimed the | |
3934 | * responsibility of cleaning up a group before queue cleanup code | |
3935 | * get to the group. | |
3936 | * | |
3937 | * Do not call synchronize_rcu() unconditionally as there are drivers | |
3938 | * which create/delete request queue hundreds of times during scan/boot | |
3939 | * and synchronize_rcu() can take significant time and slow down boot. | |
3940 | */ | |
3941 | if (wait) | |
3942 | synchronize_rcu(); | |
2abae55f VG |
3943 | |
3944 | #ifdef CONFIG_CFQ_GROUP_IOSCHED | |
3945 | /* Free up per cpu stats for root group */ | |
3946 | free_percpu(cfqd->root_group.blkg.stats_cpu); | |
3947 | #endif | |
56edf7d7 | 3948 | kfree(cfqd); |
1da177e4 LT |
3949 | } |
3950 | ||
80b15c73 KK |
3951 | static int cfq_alloc_cic_index(void) |
3952 | { | |
3953 | int index, error; | |
3954 | ||
3955 | do { | |
3956 | if (!ida_pre_get(&cic_index_ida, GFP_KERNEL)) | |
3957 | return -ENOMEM; | |
3958 | ||
3959 | spin_lock(&cic_index_lock); | |
3960 | error = ida_get_new(&cic_index_ida, &index); | |
3961 | spin_unlock(&cic_index_lock); | |
3962 | if (error && error != -EAGAIN) | |
3963 | return error; | |
3964 | } while (error); | |
3965 | ||
3966 | return index; | |
3967 | } | |
3968 | ||
165125e1 | 3969 | static void *cfq_init_queue(struct request_queue *q) |
1da177e4 LT |
3970 | { |
3971 | struct cfq_data *cfqd; | |
718eee05 | 3972 | int i, j; |
cdb16e8f | 3973 | struct cfq_group *cfqg; |
615f0259 | 3974 | struct cfq_rb_root *st; |
1da177e4 | 3975 | |
80b15c73 KK |
3976 | i = cfq_alloc_cic_index(); |
3977 | if (i < 0) | |
3978 | return NULL; | |
3979 | ||
94f6030c | 3980 | cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL | __GFP_ZERO, q->node); |
1da177e4 | 3981 | if (!cfqd) |
bc1c1169 | 3982 | return NULL; |
1da177e4 | 3983 | |
30d7b944 SL |
3984 | /* |
3985 | * Don't need take queue_lock in the routine, since we are | |
3986 | * initializing the ioscheduler, and nobody is using cfqd | |
3987 | */ | |
80b15c73 KK |
3988 | cfqd->cic_index = i; |
3989 | ||
1fa8f6d6 VG |
3990 | /* Init root service tree */ |
3991 | cfqd->grp_service_tree = CFQ_RB_ROOT; | |
3992 | ||
cdb16e8f VG |
3993 | /* Init root group */ |
3994 | cfqg = &cfqd->root_group; | |
615f0259 VG |
3995 | for_each_cfqg_st(cfqg, i, j, st) |
3996 | *st = CFQ_RB_ROOT; | |
1fa8f6d6 | 3997 | RB_CLEAR_NODE(&cfqg->rb_node); |
26a2ac00 | 3998 | |
25bc6b07 VG |
3999 | /* Give preference to root group over other groups */ |
4000 | cfqg->weight = 2*BLKIO_WEIGHT_DEFAULT; | |
4001 | ||
25fb5169 | 4002 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
b1c35769 | 4003 | /* |
56edf7d7 VG |
4004 | * Set root group reference to 2. One reference will be dropped when |
4005 | * all groups on cfqd->cfqg_list are being deleted during queue exit. | |
4006 | * Other reference will remain there as we don't want to delete this | |
4007 | * group as it is statically allocated and gets destroyed when | |
4008 | * throtl_data goes away. | |
b1c35769 | 4009 | */ |
56edf7d7 | 4010 | cfqg->ref = 2; |
5624a4e4 VG |
4011 | |
4012 | if (blkio_alloc_blkg_stats(&cfqg->blkg)) { | |
4013 | kfree(cfqg); | |
4014 | kfree(cfqd); | |
4015 | return NULL; | |
4016 | } | |
4017 | ||
dcf097b2 | 4018 | rcu_read_lock(); |
5624a4e4 | 4019 | |
e98ef89b VG |
4020 | cfq_blkiocg_add_blkio_group(&blkio_root_cgroup, &cfqg->blkg, |
4021 | (void *)cfqd, 0); | |
dcf097b2 | 4022 | rcu_read_unlock(); |
56edf7d7 VG |
4023 | cfqd->nr_blkcg_linked_grps++; |
4024 | ||
4025 | /* Add group on cfqd->cfqg_list */ | |
4026 | hlist_add_head(&cfqg->cfqd_node, &cfqd->cfqg_list); | |
25fb5169 | 4027 | #endif |
26a2ac00 JA |
4028 | /* |
4029 | * Not strictly needed (since RB_ROOT just clears the node and we | |
4030 | * zeroed cfqd on alloc), but better be safe in case someone decides | |
4031 | * to add magic to the rb code | |
4032 | */ | |
4033 | for (i = 0; i < CFQ_PRIO_LISTS; i++) | |
4034 | cfqd->prio_trees[i] = RB_ROOT; | |
4035 | ||
6118b70b JA |
4036 | /* |
4037 | * Our fallback cfqq if cfq_find_alloc_queue() runs into OOM issues. | |
4038 | * Grab a permanent reference to it, so that the normal code flow | |
4039 | * will not attempt to free it. | |
4040 | */ | |
4041 | cfq_init_cfqq(cfqd, &cfqd->oom_cfqq, 1, 0); | |
30d7b944 | 4042 | cfqd->oom_cfqq.ref++; |
cdb16e8f | 4043 | cfq_link_cfqq_cfqg(&cfqd->oom_cfqq, &cfqd->root_group); |
6118b70b | 4044 | |
d9ff4187 | 4045 | INIT_LIST_HEAD(&cfqd->cic_list); |
1da177e4 | 4046 | |
1da177e4 | 4047 | cfqd->queue = q; |
1da177e4 | 4048 | |
22e2c507 JA |
4049 | init_timer(&cfqd->idle_slice_timer); |
4050 | cfqd->idle_slice_timer.function = cfq_idle_slice_timer; | |
4051 | cfqd->idle_slice_timer.data = (unsigned long) cfqd; | |
4052 | ||
23e018a1 | 4053 | INIT_WORK(&cfqd->unplug_work, cfq_kick_queue); |
22e2c507 | 4054 | |
1da177e4 | 4055 | cfqd->cfq_quantum = cfq_quantum; |
22e2c507 JA |
4056 | cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; |
4057 | cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; | |
1da177e4 LT |
4058 | cfqd->cfq_back_max = cfq_back_max; |
4059 | cfqd->cfq_back_penalty = cfq_back_penalty; | |
22e2c507 JA |
4060 | cfqd->cfq_slice[0] = cfq_slice_async; |
4061 | cfqd->cfq_slice[1] = cfq_slice_sync; | |
4062 | cfqd->cfq_slice_async_rq = cfq_slice_async_rq; | |
4063 | cfqd->cfq_slice_idle = cfq_slice_idle; | |
80bdf0c7 | 4064 | cfqd->cfq_group_idle = cfq_group_idle; |
963b72fc | 4065 | cfqd->cfq_latency = 1; |
e459dd08 | 4066 | cfqd->hw_tag = -1; |
edc71131 CZ |
4067 | /* |
4068 | * we optimistically start assuming sync ops weren't delayed in last | |
4069 | * second, in order to have larger depth for async operations. | |
4070 | */ | |
573412b2 | 4071 | cfqd->last_delayed_sync = jiffies - HZ; |
bc1c1169 | 4072 | return cfqd; |
1da177e4 LT |
4073 | } |
4074 | ||
4075 | static void cfq_slab_kill(void) | |
4076 | { | |
d6de8be7 JA |
4077 | /* |
4078 | * Caller already ensured that pending RCU callbacks are completed, | |
4079 | * so we should have no busy allocations at this point. | |
4080 | */ | |
1da177e4 LT |
4081 | if (cfq_pool) |
4082 | kmem_cache_destroy(cfq_pool); | |
4083 | if (cfq_ioc_pool) | |
4084 | kmem_cache_destroy(cfq_ioc_pool); | |
4085 | } | |
4086 | ||
4087 | static int __init cfq_slab_setup(void) | |
4088 | { | |
0a31bd5f | 4089 | cfq_pool = KMEM_CACHE(cfq_queue, 0); |
1da177e4 LT |
4090 | if (!cfq_pool) |
4091 | goto fail; | |
4092 | ||
34e6bbf2 | 4093 | cfq_ioc_pool = KMEM_CACHE(cfq_io_context, 0); |
1da177e4 LT |
4094 | if (!cfq_ioc_pool) |
4095 | goto fail; | |
4096 | ||
4097 | return 0; | |
4098 | fail: | |
4099 | cfq_slab_kill(); | |
4100 | return -ENOMEM; | |
4101 | } | |
4102 | ||
1da177e4 LT |
4103 | /* |
4104 | * sysfs parts below --> | |
4105 | */ | |
1da177e4 LT |
4106 | static ssize_t |
4107 | cfq_var_show(unsigned int var, char *page) | |
4108 | { | |
4109 | return sprintf(page, "%d\n", var); | |
4110 | } | |
4111 | ||
4112 | static ssize_t | |
4113 | cfq_var_store(unsigned int *var, const char *page, size_t count) | |
4114 | { | |
4115 | char *p = (char *) page; | |
4116 | ||
4117 | *var = simple_strtoul(p, &p, 10); | |
4118 | return count; | |
4119 | } | |
4120 | ||
1da177e4 | 4121 | #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ |
b374d18a | 4122 | static ssize_t __FUNC(struct elevator_queue *e, char *page) \ |
1da177e4 | 4123 | { \ |
3d1ab40f | 4124 | struct cfq_data *cfqd = e->elevator_data; \ |
1da177e4 LT |
4125 | unsigned int __data = __VAR; \ |
4126 | if (__CONV) \ | |
4127 | __data = jiffies_to_msecs(__data); \ | |
4128 | return cfq_var_show(__data, (page)); \ | |
4129 | } | |
4130 | SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); | |
22e2c507 JA |
4131 | SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1); |
4132 | SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1); | |
e572ec7e AV |
4133 | SHOW_FUNCTION(cfq_back_seek_max_show, cfqd->cfq_back_max, 0); |
4134 | SHOW_FUNCTION(cfq_back_seek_penalty_show, cfqd->cfq_back_penalty, 0); | |
22e2c507 | 4135 | SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1); |
80bdf0c7 | 4136 | SHOW_FUNCTION(cfq_group_idle_show, cfqd->cfq_group_idle, 1); |
22e2c507 JA |
4137 | SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1); |
4138 | SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1); | |
4139 | SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0); | |
963b72fc | 4140 | SHOW_FUNCTION(cfq_low_latency_show, cfqd->cfq_latency, 0); |
1da177e4 LT |
4141 | #undef SHOW_FUNCTION |
4142 | ||
4143 | #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ | |
b374d18a | 4144 | static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \ |
1da177e4 | 4145 | { \ |
3d1ab40f | 4146 | struct cfq_data *cfqd = e->elevator_data; \ |
1da177e4 LT |
4147 | unsigned int __data; \ |
4148 | int ret = cfq_var_store(&__data, (page), count); \ | |
4149 | if (__data < (MIN)) \ | |
4150 | __data = (MIN); \ | |
4151 | else if (__data > (MAX)) \ | |
4152 | __data = (MAX); \ | |
4153 | if (__CONV) \ | |
4154 | *(__PTR) = msecs_to_jiffies(__data); \ | |
4155 | else \ | |
4156 | *(__PTR) = __data; \ | |
4157 | return ret; \ | |
4158 | } | |
4159 | STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); | |
fe094d98 JA |
4160 | STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, |
4161 | UINT_MAX, 1); | |
4162 | STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, | |
4163 | UINT_MAX, 1); | |
e572ec7e | 4164 | STORE_FUNCTION(cfq_back_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); |
fe094d98 JA |
4165 | STORE_FUNCTION(cfq_back_seek_penalty_store, &cfqd->cfq_back_penalty, 1, |
4166 | UINT_MAX, 0); | |
22e2c507 | 4167 | STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1); |
80bdf0c7 | 4168 | STORE_FUNCTION(cfq_group_idle_store, &cfqd->cfq_group_idle, 0, UINT_MAX, 1); |
22e2c507 JA |
4169 | STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1); |
4170 | STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1); | |
fe094d98 JA |
4171 | STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, |
4172 | UINT_MAX, 0); | |
963b72fc | 4173 | STORE_FUNCTION(cfq_low_latency_store, &cfqd->cfq_latency, 0, 1, 0); |
1da177e4 LT |
4174 | #undef STORE_FUNCTION |
4175 | ||
e572ec7e AV |
4176 | #define CFQ_ATTR(name) \ |
4177 | __ATTR(name, S_IRUGO|S_IWUSR, cfq_##name##_show, cfq_##name##_store) | |
4178 | ||
4179 | static struct elv_fs_entry cfq_attrs[] = { | |
4180 | CFQ_ATTR(quantum), | |
e572ec7e AV |
4181 | CFQ_ATTR(fifo_expire_sync), |
4182 | CFQ_ATTR(fifo_expire_async), | |
4183 | CFQ_ATTR(back_seek_max), | |
4184 | CFQ_ATTR(back_seek_penalty), | |
4185 | CFQ_ATTR(slice_sync), | |
4186 | CFQ_ATTR(slice_async), | |
4187 | CFQ_ATTR(slice_async_rq), | |
4188 | CFQ_ATTR(slice_idle), | |
80bdf0c7 | 4189 | CFQ_ATTR(group_idle), |
963b72fc | 4190 | CFQ_ATTR(low_latency), |
e572ec7e | 4191 | __ATTR_NULL |
1da177e4 LT |
4192 | }; |
4193 | ||
1da177e4 LT |
4194 | static struct elevator_type iosched_cfq = { |
4195 | .ops = { | |
4196 | .elevator_merge_fn = cfq_merge, | |
4197 | .elevator_merged_fn = cfq_merged_request, | |
4198 | .elevator_merge_req_fn = cfq_merged_requests, | |
da775265 | 4199 | .elevator_allow_merge_fn = cfq_allow_merge, |
812d4026 | 4200 | .elevator_bio_merged_fn = cfq_bio_merged, |
b4878f24 | 4201 | .elevator_dispatch_fn = cfq_dispatch_requests, |
1da177e4 | 4202 | .elevator_add_req_fn = cfq_insert_request, |
b4878f24 | 4203 | .elevator_activate_req_fn = cfq_activate_request, |
1da177e4 | 4204 | .elevator_deactivate_req_fn = cfq_deactivate_request, |
1da177e4 | 4205 | .elevator_completed_req_fn = cfq_completed_request, |
21183b07 JA |
4206 | .elevator_former_req_fn = elv_rb_former_request, |
4207 | .elevator_latter_req_fn = elv_rb_latter_request, | |
1da177e4 LT |
4208 | .elevator_set_req_fn = cfq_set_request, |
4209 | .elevator_put_req_fn = cfq_put_request, | |
4210 | .elevator_may_queue_fn = cfq_may_queue, | |
4211 | .elevator_init_fn = cfq_init_queue, | |
4212 | .elevator_exit_fn = cfq_exit_queue, | |
fc46379d | 4213 | .trim = cfq_free_io_context, |
1da177e4 | 4214 | }, |
3d1ab40f | 4215 | .elevator_attrs = cfq_attrs, |
1da177e4 LT |
4216 | .elevator_name = "cfq", |
4217 | .elevator_owner = THIS_MODULE, | |
4218 | }; | |
4219 | ||
3e252066 VG |
4220 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
4221 | static struct blkio_policy_type blkio_policy_cfq = { | |
4222 | .ops = { | |
4223 | .blkio_unlink_group_fn = cfq_unlink_blkio_group, | |
4224 | .blkio_update_group_weight_fn = cfq_update_blkio_group_weight, | |
4225 | }, | |
062a644d | 4226 | .plid = BLKIO_POLICY_PROP, |
3e252066 VG |
4227 | }; |
4228 | #else | |
4229 | static struct blkio_policy_type blkio_policy_cfq; | |
4230 | #endif | |
4231 | ||
1da177e4 LT |
4232 | static int __init cfq_init(void) |
4233 | { | |
22e2c507 JA |
4234 | /* |
4235 | * could be 0 on HZ < 1000 setups | |
4236 | */ | |
4237 | if (!cfq_slice_async) | |
4238 | cfq_slice_async = 1; | |
4239 | if (!cfq_slice_idle) | |
4240 | cfq_slice_idle = 1; | |
4241 | ||
80bdf0c7 VG |
4242 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
4243 | if (!cfq_group_idle) | |
4244 | cfq_group_idle = 1; | |
4245 | #else | |
4246 | cfq_group_idle = 0; | |
4247 | #endif | |
1da177e4 LT |
4248 | if (cfq_slab_setup()) |
4249 | return -ENOMEM; | |
4250 | ||
2fdd82bd | 4251 | elv_register(&iosched_cfq); |
3e252066 | 4252 | blkio_policy_register(&blkio_policy_cfq); |
1da177e4 | 4253 | |
2fdd82bd | 4254 | return 0; |
1da177e4 LT |
4255 | } |
4256 | ||
4257 | static void __exit cfq_exit(void) | |
4258 | { | |
6e9a4738 | 4259 | DECLARE_COMPLETION_ONSTACK(all_gone); |
3e252066 | 4260 | blkio_policy_unregister(&blkio_policy_cfq); |
1da177e4 | 4261 | elv_unregister(&iosched_cfq); |
334e94de | 4262 | ioc_gone = &all_gone; |
fba82272 OH |
4263 | /* ioc_gone's update must be visible before reading ioc_count */ |
4264 | smp_wmb(); | |
d6de8be7 JA |
4265 | |
4266 | /* | |
4267 | * this also protects us from entering cfq_slab_kill() with | |
4268 | * pending RCU callbacks | |
4269 | */ | |
245b2e70 | 4270 | if (elv_ioc_count_read(cfq_ioc_count)) |
9a11b4ed | 4271 | wait_for_completion(&all_gone); |
80b15c73 | 4272 | ida_destroy(&cic_index_ida); |
83521d3e | 4273 | cfq_slab_kill(); |
1da177e4 LT |
4274 | } |
4275 | ||
4276 | module_init(cfq_init); | |
4277 | module_exit(cfq_exit); | |
4278 | ||
4279 | MODULE_AUTHOR("Jens Axboe"); | |
4280 | MODULE_LICENSE("GPL"); | |
4281 | MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler"); |