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 JA |
56 | #define RQ_CIC(rq) \ |
57 | ((struct cfq_io_context *) (rq)->elevator_private) | |
7b679138 | 58 | #define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elevator_private2) |
7f1dc8a2 | 59 | #define RQ_CFQG(rq) (struct cfq_group *) ((rq)->elevator_private3) |
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; |
ae30c286 | 149 | struct cfq_group *orig_cfqg; |
c4e7893e VG |
150 | /* Number of sectors dispatched from queue in single dispatch round */ |
151 | unsigned long nr_sectors; | |
6118b70b JA |
152 | }; |
153 | ||
c0324a02 | 154 | /* |
718eee05 | 155 | * First index in the service_trees. |
c0324a02 CZ |
156 | * IDLE is handled separately, so it has negative index |
157 | */ | |
158 | enum wl_prio_t { | |
c0324a02 | 159 | BE_WORKLOAD = 0, |
615f0259 VG |
160 | RT_WORKLOAD = 1, |
161 | IDLE_WORKLOAD = 2, | |
b4627321 | 162 | CFQ_PRIO_NR, |
c0324a02 CZ |
163 | }; |
164 | ||
718eee05 CZ |
165 | /* |
166 | * Second index in the service_trees. | |
167 | */ | |
168 | enum wl_type_t { | |
169 | ASYNC_WORKLOAD = 0, | |
170 | SYNC_NOIDLE_WORKLOAD = 1, | |
171 | SYNC_WORKLOAD = 2 | |
172 | }; | |
173 | ||
cdb16e8f VG |
174 | /* This is per cgroup per device grouping structure */ |
175 | struct cfq_group { | |
1fa8f6d6 VG |
176 | /* group service_tree member */ |
177 | struct rb_node rb_node; | |
178 | ||
179 | /* group service_tree key */ | |
180 | u64 vdisktime; | |
25bc6b07 | 181 | unsigned int weight; |
1fa8f6d6 VG |
182 | |
183 | /* number of cfqq currently on this group */ | |
184 | int nr_cfqq; | |
185 | ||
cdb16e8f | 186 | /* |
b4627321 VG |
187 | * Per group busy queus average. Useful for workload slice calc. We |
188 | * create the array for each prio class but at run time it is used | |
189 | * only for RT and BE class and slot for IDLE class remains unused. | |
190 | * This is primarily done to avoid confusion and a gcc warning. | |
191 | */ | |
192 | unsigned int busy_queues_avg[CFQ_PRIO_NR]; | |
193 | /* | |
194 | * rr lists of queues with requests. We maintain service trees for | |
195 | * RT and BE classes. These trees are subdivided in subclasses | |
196 | * of SYNC, SYNC_NOIDLE and ASYNC based on workload type. For IDLE | |
197 | * class there is no subclassification and all the cfq queues go on | |
198 | * a single tree service_tree_idle. | |
cdb16e8f VG |
199 | * Counts are embedded in the cfq_rb_root |
200 | */ | |
201 | struct cfq_rb_root service_trees[2][3]; | |
202 | struct cfq_rb_root service_tree_idle; | |
dae739eb VG |
203 | |
204 | unsigned long saved_workload_slice; | |
205 | enum wl_type_t saved_workload; | |
206 | enum wl_prio_t saved_serving_prio; | |
25fb5169 VG |
207 | struct blkio_group blkg; |
208 | #ifdef CONFIG_CFQ_GROUP_IOSCHED | |
209 | struct hlist_node cfqd_node; | |
329a6781 | 210 | int ref; |
25fb5169 | 211 | #endif |
80bdf0c7 VG |
212 | /* number of requests that are on the dispatch list or inside driver */ |
213 | int dispatched; | |
cdb16e8f | 214 | }; |
718eee05 | 215 | |
22e2c507 JA |
216 | /* |
217 | * Per block device queue structure | |
218 | */ | |
1da177e4 | 219 | struct cfq_data { |
165125e1 | 220 | struct request_queue *queue; |
1fa8f6d6 VG |
221 | /* Root service tree for cfq_groups */ |
222 | struct cfq_rb_root grp_service_tree; | |
cdb16e8f | 223 | struct cfq_group root_group; |
22e2c507 | 224 | |
c0324a02 CZ |
225 | /* |
226 | * The priority currently being served | |
22e2c507 | 227 | */ |
c0324a02 | 228 | enum wl_prio_t serving_prio; |
718eee05 CZ |
229 | enum wl_type_t serving_type; |
230 | unsigned long workload_expires; | |
cdb16e8f | 231 | struct cfq_group *serving_group; |
a36e71f9 JA |
232 | |
233 | /* | |
234 | * Each priority tree is sorted by next_request position. These | |
235 | * trees are used when determining if two or more queues are | |
236 | * interleaving requests (see cfq_close_cooperator). | |
237 | */ | |
238 | struct rb_root prio_trees[CFQ_PRIO_LISTS]; | |
239 | ||
22e2c507 JA |
240 | unsigned int busy_queues; |
241 | ||
53c583d2 CZ |
242 | int rq_in_driver; |
243 | int rq_in_flight[2]; | |
45333d5a AC |
244 | |
245 | /* | |
246 | * queue-depth detection | |
247 | */ | |
248 | int rq_queued; | |
25776e35 | 249 | int hw_tag; |
e459dd08 CZ |
250 | /* |
251 | * hw_tag can be | |
252 | * -1 => indeterminate, (cfq will behave as if NCQ is present, to allow better detection) | |
253 | * 1 => NCQ is present (hw_tag_est_depth is the estimated max depth) | |
254 | * 0 => no NCQ | |
255 | */ | |
256 | int hw_tag_est_depth; | |
257 | unsigned int hw_tag_samples; | |
1da177e4 | 258 | |
22e2c507 JA |
259 | /* |
260 | * idle window management | |
261 | */ | |
262 | struct timer_list idle_slice_timer; | |
23e018a1 | 263 | struct work_struct unplug_work; |
1da177e4 | 264 | |
22e2c507 JA |
265 | struct cfq_queue *active_queue; |
266 | struct cfq_io_context *active_cic; | |
22e2c507 | 267 | |
c2dea2d1 VT |
268 | /* |
269 | * async queue for each priority case | |
270 | */ | |
271 | struct cfq_queue *async_cfqq[2][IOPRIO_BE_NR]; | |
272 | struct cfq_queue *async_idle_cfqq; | |
15c31be4 | 273 | |
6d048f53 | 274 | sector_t last_position; |
1da177e4 | 275 | |
1da177e4 LT |
276 | /* |
277 | * tunables, see top of file | |
278 | */ | |
279 | unsigned int cfq_quantum; | |
22e2c507 | 280 | unsigned int cfq_fifo_expire[2]; |
1da177e4 LT |
281 | unsigned int cfq_back_penalty; |
282 | unsigned int cfq_back_max; | |
22e2c507 JA |
283 | unsigned int cfq_slice[2]; |
284 | unsigned int cfq_slice_async_rq; | |
285 | unsigned int cfq_slice_idle; | |
80bdf0c7 | 286 | unsigned int cfq_group_idle; |
963b72fc | 287 | unsigned int cfq_latency; |
ae30c286 | 288 | unsigned int cfq_group_isolation; |
d9ff4187 | 289 | |
80b15c73 | 290 | unsigned int cic_index; |
d9ff4187 | 291 | struct list_head cic_list; |
1da177e4 | 292 | |
6118b70b JA |
293 | /* |
294 | * Fallback dummy cfqq for extreme OOM conditions | |
295 | */ | |
296 | struct cfq_queue oom_cfqq; | |
365722bb | 297 | |
573412b2 | 298 | unsigned long last_delayed_sync; |
25fb5169 VG |
299 | |
300 | /* List of cfq groups being managed on this device*/ | |
301 | struct hlist_head cfqg_list; | |
bb729bc9 | 302 | struct rcu_head rcu; |
1da177e4 LT |
303 | }; |
304 | ||
25fb5169 VG |
305 | static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd); |
306 | ||
cdb16e8f VG |
307 | static struct cfq_rb_root *service_tree_for(struct cfq_group *cfqg, |
308 | enum wl_prio_t prio, | |
65b32a57 | 309 | enum wl_type_t type) |
c0324a02 | 310 | { |
1fa8f6d6 VG |
311 | if (!cfqg) |
312 | return NULL; | |
313 | ||
c0324a02 | 314 | if (prio == IDLE_WORKLOAD) |
cdb16e8f | 315 | return &cfqg->service_tree_idle; |
c0324a02 | 316 | |
cdb16e8f | 317 | return &cfqg->service_trees[prio][type]; |
c0324a02 CZ |
318 | } |
319 | ||
3b18152c | 320 | enum cfqq_state_flags { |
b0b8d749 JA |
321 | CFQ_CFQQ_FLAG_on_rr = 0, /* on round-robin busy list */ |
322 | CFQ_CFQQ_FLAG_wait_request, /* waiting for a request */ | |
b029195d | 323 | CFQ_CFQQ_FLAG_must_dispatch, /* must be allowed a dispatch */ |
b0b8d749 | 324 | CFQ_CFQQ_FLAG_must_alloc_slice, /* per-slice must_alloc flag */ |
b0b8d749 JA |
325 | CFQ_CFQQ_FLAG_fifo_expire, /* FIFO checked in this slice */ |
326 | CFQ_CFQQ_FLAG_idle_window, /* slice idling enabled */ | |
327 | CFQ_CFQQ_FLAG_prio_changed, /* task priority has changed */ | |
44f7c160 | 328 | CFQ_CFQQ_FLAG_slice_new, /* no requests dispatched in slice */ |
91fac317 | 329 | CFQ_CFQQ_FLAG_sync, /* synchronous queue */ |
b3b6d040 | 330 | CFQ_CFQQ_FLAG_coop, /* cfqq is shared */ |
ae54abed | 331 | CFQ_CFQQ_FLAG_split_coop, /* shared cfqq will be splitted */ |
76280aff | 332 | CFQ_CFQQ_FLAG_deep, /* sync cfqq experienced large depth */ |
f75edf2d | 333 | CFQ_CFQQ_FLAG_wait_busy, /* Waiting for next request */ |
3b18152c JA |
334 | }; |
335 | ||
336 | #define CFQ_CFQQ_FNS(name) \ | |
337 | static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \ | |
338 | { \ | |
fe094d98 | 339 | (cfqq)->flags |= (1 << CFQ_CFQQ_FLAG_##name); \ |
3b18152c JA |
340 | } \ |
341 | static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \ | |
342 | { \ | |
fe094d98 | 343 | (cfqq)->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \ |
3b18152c JA |
344 | } \ |
345 | static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \ | |
346 | { \ | |
fe094d98 | 347 | return ((cfqq)->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \ |
3b18152c JA |
348 | } |
349 | ||
350 | CFQ_CFQQ_FNS(on_rr); | |
351 | CFQ_CFQQ_FNS(wait_request); | |
b029195d | 352 | CFQ_CFQQ_FNS(must_dispatch); |
3b18152c | 353 | CFQ_CFQQ_FNS(must_alloc_slice); |
3b18152c JA |
354 | CFQ_CFQQ_FNS(fifo_expire); |
355 | CFQ_CFQQ_FNS(idle_window); | |
356 | CFQ_CFQQ_FNS(prio_changed); | |
44f7c160 | 357 | CFQ_CFQQ_FNS(slice_new); |
91fac317 | 358 | CFQ_CFQQ_FNS(sync); |
a36e71f9 | 359 | CFQ_CFQQ_FNS(coop); |
ae54abed | 360 | CFQ_CFQQ_FNS(split_coop); |
76280aff | 361 | CFQ_CFQQ_FNS(deep); |
f75edf2d | 362 | CFQ_CFQQ_FNS(wait_busy); |
3b18152c JA |
363 | #undef CFQ_CFQQ_FNS |
364 | ||
afc24d49 | 365 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
2868ef7b VG |
366 | #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \ |
367 | blk_add_trace_msg((cfqd)->queue, "cfq%d%c %s " fmt, (cfqq)->pid, \ | |
368 | cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \ | |
369 | blkg_path(&(cfqq)->cfqg->blkg), ##args); | |
370 | ||
371 | #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) \ | |
372 | blk_add_trace_msg((cfqd)->queue, "%s " fmt, \ | |
373 | blkg_path(&(cfqg)->blkg), ##args); \ | |
374 | ||
375 | #else | |
7b679138 JA |
376 | #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \ |
377 | blk_add_trace_msg((cfqd)->queue, "cfq%d " fmt, (cfqq)->pid, ##args) | |
2868ef7b VG |
378 | #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) do {} while (0); |
379 | #endif | |
7b679138 JA |
380 | #define cfq_log(cfqd, fmt, args...) \ |
381 | blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args) | |
382 | ||
615f0259 VG |
383 | /* Traverses through cfq group service trees */ |
384 | #define for_each_cfqg_st(cfqg, i, j, st) \ | |
385 | for (i = 0; i <= IDLE_WORKLOAD; i++) \ | |
386 | for (j = 0, st = i < IDLE_WORKLOAD ? &cfqg->service_trees[i][j]\ | |
387 | : &cfqg->service_tree_idle; \ | |
388 | (i < IDLE_WORKLOAD && j <= SYNC_WORKLOAD) || \ | |
389 | (i == IDLE_WORKLOAD && j == 0); \ | |
390 | j++, st = i < IDLE_WORKLOAD ? \ | |
391 | &cfqg->service_trees[i][j]: NULL) \ | |
392 | ||
393 | ||
02b35081 VG |
394 | static inline bool iops_mode(struct cfq_data *cfqd) |
395 | { | |
396 | /* | |
397 | * If we are not idling on queues and it is a NCQ drive, parallel | |
398 | * execution of requests is on and measuring time is not possible | |
399 | * in most of the cases until and unless we drive shallower queue | |
400 | * depths and that becomes a performance bottleneck. In such cases | |
401 | * switch to start providing fairness in terms of number of IOs. | |
402 | */ | |
403 | if (!cfqd->cfq_slice_idle && cfqd->hw_tag) | |
404 | return true; | |
405 | else | |
406 | return false; | |
407 | } | |
408 | ||
c0324a02 CZ |
409 | static inline enum wl_prio_t cfqq_prio(struct cfq_queue *cfqq) |
410 | { | |
411 | if (cfq_class_idle(cfqq)) | |
412 | return IDLE_WORKLOAD; | |
413 | if (cfq_class_rt(cfqq)) | |
414 | return RT_WORKLOAD; | |
415 | return BE_WORKLOAD; | |
416 | } | |
417 | ||
718eee05 CZ |
418 | |
419 | static enum wl_type_t cfqq_type(struct cfq_queue *cfqq) | |
420 | { | |
421 | if (!cfq_cfqq_sync(cfqq)) | |
422 | return ASYNC_WORKLOAD; | |
423 | if (!cfq_cfqq_idle_window(cfqq)) | |
424 | return SYNC_NOIDLE_WORKLOAD; | |
425 | return SYNC_WORKLOAD; | |
426 | } | |
427 | ||
58ff82f3 VG |
428 | static inline int cfq_group_busy_queues_wl(enum wl_prio_t wl, |
429 | struct cfq_data *cfqd, | |
430 | struct cfq_group *cfqg) | |
c0324a02 CZ |
431 | { |
432 | if (wl == IDLE_WORKLOAD) | |
cdb16e8f | 433 | return cfqg->service_tree_idle.count; |
c0324a02 | 434 | |
cdb16e8f VG |
435 | return cfqg->service_trees[wl][ASYNC_WORKLOAD].count |
436 | + cfqg->service_trees[wl][SYNC_NOIDLE_WORKLOAD].count | |
437 | + cfqg->service_trees[wl][SYNC_WORKLOAD].count; | |
c0324a02 CZ |
438 | } |
439 | ||
f26bd1f0 VG |
440 | static inline int cfqg_busy_async_queues(struct cfq_data *cfqd, |
441 | struct cfq_group *cfqg) | |
442 | { | |
443 | return cfqg->service_trees[RT_WORKLOAD][ASYNC_WORKLOAD].count | |
444 | + cfqg->service_trees[BE_WORKLOAD][ASYNC_WORKLOAD].count; | |
445 | } | |
446 | ||
165125e1 | 447 | static void cfq_dispatch_insert(struct request_queue *, struct request *); |
a6151c3a | 448 | static struct cfq_queue *cfq_get_queue(struct cfq_data *, bool, |
fd0928df | 449 | struct io_context *, gfp_t); |
4ac845a2 | 450 | static struct cfq_io_context *cfq_cic_lookup(struct cfq_data *, |
91fac317 VT |
451 | struct io_context *); |
452 | ||
453 | static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_context *cic, | |
a6151c3a | 454 | bool is_sync) |
91fac317 | 455 | { |
a6151c3a | 456 | return cic->cfqq[is_sync]; |
91fac317 VT |
457 | } |
458 | ||
459 | static inline void cic_set_cfqq(struct cfq_io_context *cic, | |
a6151c3a | 460 | struct cfq_queue *cfqq, bool is_sync) |
91fac317 | 461 | { |
a6151c3a | 462 | cic->cfqq[is_sync] = cfqq; |
91fac317 VT |
463 | } |
464 | ||
bca4b914 | 465 | #define CIC_DEAD_KEY 1ul |
80b15c73 | 466 | #define CIC_DEAD_INDEX_SHIFT 1 |
bca4b914 KK |
467 | |
468 | static inline void *cfqd_dead_key(struct cfq_data *cfqd) | |
469 | { | |
80b15c73 | 470 | return (void *)(cfqd->cic_index << CIC_DEAD_INDEX_SHIFT | CIC_DEAD_KEY); |
bca4b914 KK |
471 | } |
472 | ||
473 | static inline struct cfq_data *cic_to_cfqd(struct cfq_io_context *cic) | |
474 | { | |
475 | struct cfq_data *cfqd = cic->key; | |
476 | ||
477 | if (unlikely((unsigned long) cfqd & CIC_DEAD_KEY)) | |
478 | return NULL; | |
479 | ||
480 | return cfqd; | |
481 | } | |
482 | ||
91fac317 VT |
483 | /* |
484 | * We regard a request as SYNC, if it's either a read or has the SYNC bit | |
485 | * set (in which case it could also be direct WRITE). | |
486 | */ | |
a6151c3a | 487 | static inline bool cfq_bio_sync(struct bio *bio) |
91fac317 | 488 | { |
7b6d91da | 489 | return bio_data_dir(bio) == READ || (bio->bi_rw & REQ_SYNC); |
91fac317 | 490 | } |
1da177e4 | 491 | |
99f95e52 AM |
492 | /* |
493 | * scheduler run of queue, if there are requests pending and no one in the | |
494 | * driver that will restart queueing | |
495 | */ | |
23e018a1 | 496 | static inline void cfq_schedule_dispatch(struct cfq_data *cfqd) |
99f95e52 | 497 | { |
7b679138 JA |
498 | if (cfqd->busy_queues) { |
499 | cfq_log(cfqd, "schedule dispatch"); | |
23e018a1 | 500 | kblockd_schedule_work(cfqd->queue, &cfqd->unplug_work); |
7b679138 | 501 | } |
99f95e52 AM |
502 | } |
503 | ||
165125e1 | 504 | static int cfq_queue_empty(struct request_queue *q) |
99f95e52 AM |
505 | { |
506 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
507 | ||
f04a6424 | 508 | return !cfqd->rq_queued; |
99f95e52 AM |
509 | } |
510 | ||
44f7c160 JA |
511 | /* |
512 | * Scale schedule slice based on io priority. Use the sync time slice only | |
513 | * if a queue is marked sync and has sync io queued. A sync queue with async | |
514 | * io only, should not get full sync slice length. | |
515 | */ | |
a6151c3a | 516 | static inline int cfq_prio_slice(struct cfq_data *cfqd, bool sync, |
d9e7620e | 517 | unsigned short prio) |
44f7c160 | 518 | { |
d9e7620e | 519 | const int base_slice = cfqd->cfq_slice[sync]; |
44f7c160 | 520 | |
d9e7620e JA |
521 | WARN_ON(prio >= IOPRIO_BE_NR); |
522 | ||
523 | return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - prio)); | |
524 | } | |
44f7c160 | 525 | |
d9e7620e JA |
526 | static inline int |
527 | cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
528 | { | |
529 | return cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio); | |
44f7c160 JA |
530 | } |
531 | ||
25bc6b07 VG |
532 | static inline u64 cfq_scale_slice(unsigned long delta, struct cfq_group *cfqg) |
533 | { | |
534 | u64 d = delta << CFQ_SERVICE_SHIFT; | |
535 | ||
536 | d = d * BLKIO_WEIGHT_DEFAULT; | |
537 | do_div(d, cfqg->weight); | |
538 | return d; | |
539 | } | |
540 | ||
541 | static inline u64 max_vdisktime(u64 min_vdisktime, u64 vdisktime) | |
542 | { | |
543 | s64 delta = (s64)(vdisktime - min_vdisktime); | |
544 | if (delta > 0) | |
545 | min_vdisktime = vdisktime; | |
546 | ||
547 | return min_vdisktime; | |
548 | } | |
549 | ||
550 | static inline u64 min_vdisktime(u64 min_vdisktime, u64 vdisktime) | |
551 | { | |
552 | s64 delta = (s64)(vdisktime - min_vdisktime); | |
553 | if (delta < 0) | |
554 | min_vdisktime = vdisktime; | |
555 | ||
556 | return min_vdisktime; | |
557 | } | |
558 | ||
559 | static void update_min_vdisktime(struct cfq_rb_root *st) | |
560 | { | |
561 | u64 vdisktime = st->min_vdisktime; | |
562 | struct cfq_group *cfqg; | |
563 | ||
25bc6b07 VG |
564 | if (st->left) { |
565 | cfqg = rb_entry_cfqg(st->left); | |
566 | vdisktime = min_vdisktime(vdisktime, cfqg->vdisktime); | |
567 | } | |
568 | ||
569 | st->min_vdisktime = max_vdisktime(st->min_vdisktime, vdisktime); | |
570 | } | |
571 | ||
5db5d642 CZ |
572 | /* |
573 | * get averaged number of queues of RT/BE priority. | |
574 | * average is updated, with a formula that gives more weight to higher numbers, | |
575 | * to quickly follows sudden increases and decrease slowly | |
576 | */ | |
577 | ||
58ff82f3 VG |
578 | static inline unsigned cfq_group_get_avg_queues(struct cfq_data *cfqd, |
579 | struct cfq_group *cfqg, bool rt) | |
5869619c | 580 | { |
5db5d642 CZ |
581 | unsigned min_q, max_q; |
582 | unsigned mult = cfq_hist_divisor - 1; | |
583 | unsigned round = cfq_hist_divisor / 2; | |
58ff82f3 | 584 | unsigned busy = cfq_group_busy_queues_wl(rt, cfqd, cfqg); |
5db5d642 | 585 | |
58ff82f3 VG |
586 | min_q = min(cfqg->busy_queues_avg[rt], busy); |
587 | max_q = max(cfqg->busy_queues_avg[rt], busy); | |
588 | cfqg->busy_queues_avg[rt] = (mult * max_q + min_q + round) / | |
5db5d642 | 589 | cfq_hist_divisor; |
58ff82f3 VG |
590 | return cfqg->busy_queues_avg[rt]; |
591 | } | |
592 | ||
593 | static inline unsigned | |
594 | cfq_group_slice(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
595 | { | |
596 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
597 | ||
598 | return cfq_target_latency * cfqg->weight / st->total_weight; | |
5db5d642 CZ |
599 | } |
600 | ||
44f7c160 JA |
601 | static inline void |
602 | cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
603 | { | |
5db5d642 CZ |
604 | unsigned slice = cfq_prio_to_slice(cfqd, cfqq); |
605 | if (cfqd->cfq_latency) { | |
58ff82f3 VG |
606 | /* |
607 | * interested queues (we consider only the ones with the same | |
608 | * priority class in the cfq group) | |
609 | */ | |
610 | unsigned iq = cfq_group_get_avg_queues(cfqd, cfqq->cfqg, | |
611 | cfq_class_rt(cfqq)); | |
5db5d642 CZ |
612 | unsigned sync_slice = cfqd->cfq_slice[1]; |
613 | unsigned expect_latency = sync_slice * iq; | |
58ff82f3 VG |
614 | unsigned group_slice = cfq_group_slice(cfqd, cfqq->cfqg); |
615 | ||
616 | if (expect_latency > group_slice) { | |
5db5d642 CZ |
617 | unsigned base_low_slice = 2 * cfqd->cfq_slice_idle; |
618 | /* scale low_slice according to IO priority | |
619 | * and sync vs async */ | |
620 | unsigned low_slice = | |
621 | min(slice, base_low_slice * slice / sync_slice); | |
622 | /* the adapted slice value is scaled to fit all iqs | |
623 | * into the target latency */ | |
58ff82f3 | 624 | slice = max(slice * group_slice / expect_latency, |
5db5d642 CZ |
625 | low_slice); |
626 | } | |
627 | } | |
dae739eb | 628 | cfqq->slice_start = jiffies; |
5db5d642 | 629 | cfqq->slice_end = jiffies + slice; |
f75edf2d | 630 | cfqq->allocated_slice = slice; |
7b679138 | 631 | cfq_log_cfqq(cfqd, cfqq, "set_slice=%lu", cfqq->slice_end - jiffies); |
44f7c160 JA |
632 | } |
633 | ||
634 | /* | |
635 | * We need to wrap this check in cfq_cfqq_slice_new(), since ->slice_end | |
636 | * isn't valid until the first request from the dispatch is activated | |
637 | * and the slice time set. | |
638 | */ | |
a6151c3a | 639 | static inline bool cfq_slice_used(struct cfq_queue *cfqq) |
44f7c160 JA |
640 | { |
641 | if (cfq_cfqq_slice_new(cfqq)) | |
c1e44756 | 642 | return false; |
44f7c160 | 643 | if (time_before(jiffies, cfqq->slice_end)) |
c1e44756 | 644 | return false; |
44f7c160 | 645 | |
c1e44756 | 646 | return true; |
44f7c160 JA |
647 | } |
648 | ||
1da177e4 | 649 | /* |
5e705374 | 650 | * Lifted from AS - choose which of rq1 and rq2 that is best served now. |
1da177e4 | 651 | * We choose the request that is closest to the head right now. Distance |
e8a99053 | 652 | * behind the head is penalized and only allowed to a certain extent. |
1da177e4 | 653 | */ |
5e705374 | 654 | static struct request * |
cf7c25cf | 655 | cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2, sector_t last) |
1da177e4 | 656 | { |
cf7c25cf | 657 | sector_t s1, s2, d1 = 0, d2 = 0; |
1da177e4 | 658 | unsigned long back_max; |
e8a99053 AM |
659 | #define CFQ_RQ1_WRAP 0x01 /* request 1 wraps */ |
660 | #define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */ | |
661 | unsigned wrap = 0; /* bit mask: requests behind the disk head? */ | |
1da177e4 | 662 | |
5e705374 JA |
663 | if (rq1 == NULL || rq1 == rq2) |
664 | return rq2; | |
665 | if (rq2 == NULL) | |
666 | return rq1; | |
9c2c38a1 | 667 | |
5e705374 JA |
668 | if (rq_is_sync(rq1) && !rq_is_sync(rq2)) |
669 | return rq1; | |
670 | else if (rq_is_sync(rq2) && !rq_is_sync(rq1)) | |
671 | return rq2; | |
7b6d91da | 672 | if ((rq1->cmd_flags & REQ_META) && !(rq2->cmd_flags & REQ_META)) |
374f84ac | 673 | return rq1; |
7b6d91da CH |
674 | else if ((rq2->cmd_flags & REQ_META) && |
675 | !(rq1->cmd_flags & REQ_META)) | |
374f84ac | 676 | return rq2; |
1da177e4 | 677 | |
83096ebf TH |
678 | s1 = blk_rq_pos(rq1); |
679 | s2 = blk_rq_pos(rq2); | |
1da177e4 | 680 | |
1da177e4 LT |
681 | /* |
682 | * by definition, 1KiB is 2 sectors | |
683 | */ | |
684 | back_max = cfqd->cfq_back_max * 2; | |
685 | ||
686 | /* | |
687 | * Strict one way elevator _except_ in the case where we allow | |
688 | * short backward seeks which are biased as twice the cost of a | |
689 | * similar forward seek. | |
690 | */ | |
691 | if (s1 >= last) | |
692 | d1 = s1 - last; | |
693 | else if (s1 + back_max >= last) | |
694 | d1 = (last - s1) * cfqd->cfq_back_penalty; | |
695 | else | |
e8a99053 | 696 | wrap |= CFQ_RQ1_WRAP; |
1da177e4 LT |
697 | |
698 | if (s2 >= last) | |
699 | d2 = s2 - last; | |
700 | else if (s2 + back_max >= last) | |
701 | d2 = (last - s2) * cfqd->cfq_back_penalty; | |
702 | else | |
e8a99053 | 703 | wrap |= CFQ_RQ2_WRAP; |
1da177e4 LT |
704 | |
705 | /* Found required data */ | |
e8a99053 AM |
706 | |
707 | /* | |
708 | * By doing switch() on the bit mask "wrap" we avoid having to | |
709 | * check two variables for all permutations: --> faster! | |
710 | */ | |
711 | switch (wrap) { | |
5e705374 | 712 | case 0: /* common case for CFQ: rq1 and rq2 not wrapped */ |
e8a99053 | 713 | if (d1 < d2) |
5e705374 | 714 | return rq1; |
e8a99053 | 715 | else if (d2 < d1) |
5e705374 | 716 | return rq2; |
e8a99053 AM |
717 | else { |
718 | if (s1 >= s2) | |
5e705374 | 719 | return rq1; |
e8a99053 | 720 | else |
5e705374 | 721 | return rq2; |
e8a99053 | 722 | } |
1da177e4 | 723 | |
e8a99053 | 724 | case CFQ_RQ2_WRAP: |
5e705374 | 725 | return rq1; |
e8a99053 | 726 | case CFQ_RQ1_WRAP: |
5e705374 JA |
727 | return rq2; |
728 | case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both rqs wrapped */ | |
e8a99053 AM |
729 | default: |
730 | /* | |
731 | * Since both rqs are wrapped, | |
732 | * start with the one that's further behind head | |
733 | * (--> only *one* back seek required), | |
734 | * since back seek takes more time than forward. | |
735 | */ | |
736 | if (s1 <= s2) | |
5e705374 | 737 | return rq1; |
1da177e4 | 738 | else |
5e705374 | 739 | return rq2; |
1da177e4 LT |
740 | } |
741 | } | |
742 | ||
498d3aa2 JA |
743 | /* |
744 | * The below is leftmost cache rbtree addon | |
745 | */ | |
0871714e | 746 | static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root) |
cc09e299 | 747 | { |
615f0259 VG |
748 | /* Service tree is empty */ |
749 | if (!root->count) | |
750 | return NULL; | |
751 | ||
cc09e299 JA |
752 | if (!root->left) |
753 | root->left = rb_first(&root->rb); | |
754 | ||
0871714e JA |
755 | if (root->left) |
756 | return rb_entry(root->left, struct cfq_queue, rb_node); | |
757 | ||
758 | return NULL; | |
cc09e299 JA |
759 | } |
760 | ||
1fa8f6d6 VG |
761 | static struct cfq_group *cfq_rb_first_group(struct cfq_rb_root *root) |
762 | { | |
763 | if (!root->left) | |
764 | root->left = rb_first(&root->rb); | |
765 | ||
766 | if (root->left) | |
767 | return rb_entry_cfqg(root->left); | |
768 | ||
769 | return NULL; | |
770 | } | |
771 | ||
a36e71f9 JA |
772 | static void rb_erase_init(struct rb_node *n, struct rb_root *root) |
773 | { | |
774 | rb_erase(n, root); | |
775 | RB_CLEAR_NODE(n); | |
776 | } | |
777 | ||
cc09e299 JA |
778 | static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root) |
779 | { | |
780 | if (root->left == n) | |
781 | root->left = NULL; | |
a36e71f9 | 782 | rb_erase_init(n, &root->rb); |
aa6f6a3d | 783 | --root->count; |
cc09e299 JA |
784 | } |
785 | ||
1da177e4 LT |
786 | /* |
787 | * would be nice to take fifo expire time into account as well | |
788 | */ | |
5e705374 JA |
789 | static struct request * |
790 | cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
791 | struct request *last) | |
1da177e4 | 792 | { |
21183b07 JA |
793 | struct rb_node *rbnext = rb_next(&last->rb_node); |
794 | struct rb_node *rbprev = rb_prev(&last->rb_node); | |
5e705374 | 795 | struct request *next = NULL, *prev = NULL; |
1da177e4 | 796 | |
21183b07 | 797 | BUG_ON(RB_EMPTY_NODE(&last->rb_node)); |
1da177e4 LT |
798 | |
799 | if (rbprev) | |
5e705374 | 800 | prev = rb_entry_rq(rbprev); |
1da177e4 | 801 | |
21183b07 | 802 | if (rbnext) |
5e705374 | 803 | next = rb_entry_rq(rbnext); |
21183b07 JA |
804 | else { |
805 | rbnext = rb_first(&cfqq->sort_list); | |
806 | if (rbnext && rbnext != &last->rb_node) | |
5e705374 | 807 | next = rb_entry_rq(rbnext); |
21183b07 | 808 | } |
1da177e4 | 809 | |
cf7c25cf | 810 | return cfq_choose_req(cfqd, next, prev, blk_rq_pos(last)); |
1da177e4 LT |
811 | } |
812 | ||
d9e7620e JA |
813 | static unsigned long cfq_slice_offset(struct cfq_data *cfqd, |
814 | struct cfq_queue *cfqq) | |
1da177e4 | 815 | { |
d9e7620e JA |
816 | /* |
817 | * just an approximation, should be ok. | |
818 | */ | |
cdb16e8f | 819 | return (cfqq->cfqg->nr_cfqq - 1) * (cfq_prio_slice(cfqd, 1, 0) - |
464191c6 | 820 | cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio)); |
d9e7620e JA |
821 | } |
822 | ||
1fa8f6d6 VG |
823 | static inline s64 |
824 | cfqg_key(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
825 | { | |
826 | return cfqg->vdisktime - st->min_vdisktime; | |
827 | } | |
828 | ||
829 | static void | |
830 | __cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
831 | { | |
832 | struct rb_node **node = &st->rb.rb_node; | |
833 | struct rb_node *parent = NULL; | |
834 | struct cfq_group *__cfqg; | |
835 | s64 key = cfqg_key(st, cfqg); | |
836 | int left = 1; | |
837 | ||
838 | while (*node != NULL) { | |
839 | parent = *node; | |
840 | __cfqg = rb_entry_cfqg(parent); | |
841 | ||
842 | if (key < cfqg_key(st, __cfqg)) | |
843 | node = &parent->rb_left; | |
844 | else { | |
845 | node = &parent->rb_right; | |
846 | left = 0; | |
847 | } | |
848 | } | |
849 | ||
850 | if (left) | |
851 | st->left = &cfqg->rb_node; | |
852 | ||
853 | rb_link_node(&cfqg->rb_node, parent, node); | |
854 | rb_insert_color(&cfqg->rb_node, &st->rb); | |
855 | } | |
856 | ||
857 | static void | |
858 | cfq_group_service_tree_add(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
859 | { | |
860 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
861 | struct cfq_group *__cfqg; | |
862 | struct rb_node *n; | |
863 | ||
864 | cfqg->nr_cfqq++; | |
760701bf | 865 | if (!RB_EMPTY_NODE(&cfqg->rb_node)) |
1fa8f6d6 VG |
866 | return; |
867 | ||
868 | /* | |
869 | * Currently put the group at the end. Later implement something | |
870 | * so that groups get lesser vtime based on their weights, so that | |
871 | * if group does not loose all if it was not continously backlogged. | |
872 | */ | |
873 | n = rb_last(&st->rb); | |
874 | if (n) { | |
875 | __cfqg = rb_entry_cfqg(n); | |
876 | cfqg->vdisktime = __cfqg->vdisktime + CFQ_IDLE_DELAY; | |
877 | } else | |
878 | cfqg->vdisktime = st->min_vdisktime; | |
879 | ||
880 | __cfq_group_service_tree_add(st, cfqg); | |
58ff82f3 | 881 | st->total_weight += cfqg->weight; |
1fa8f6d6 VG |
882 | } |
883 | ||
884 | static void | |
885 | cfq_group_service_tree_del(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
886 | { | |
887 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
888 | ||
889 | BUG_ON(cfqg->nr_cfqq < 1); | |
890 | cfqg->nr_cfqq--; | |
25bc6b07 | 891 | |
1fa8f6d6 VG |
892 | /* If there are other cfq queues under this group, don't delete it */ |
893 | if (cfqg->nr_cfqq) | |
894 | return; | |
895 | ||
2868ef7b | 896 | cfq_log_cfqg(cfqd, cfqg, "del_from_rr group"); |
58ff82f3 | 897 | st->total_weight -= cfqg->weight; |
1fa8f6d6 VG |
898 | if (!RB_EMPTY_NODE(&cfqg->rb_node)) |
899 | cfq_rb_erase(&cfqg->rb_node, st); | |
dae739eb | 900 | cfqg->saved_workload_slice = 0; |
e98ef89b | 901 | cfq_blkiocg_update_dequeue_stats(&cfqg->blkg, 1); |
dae739eb VG |
902 | } |
903 | ||
904 | static inline unsigned int cfq_cfqq_slice_usage(struct cfq_queue *cfqq) | |
905 | { | |
f75edf2d | 906 | unsigned int slice_used; |
dae739eb VG |
907 | |
908 | /* | |
909 | * Queue got expired before even a single request completed or | |
910 | * got expired immediately after first request completion. | |
911 | */ | |
912 | if (!cfqq->slice_start || cfqq->slice_start == jiffies) { | |
913 | /* | |
914 | * Also charge the seek time incurred to the group, otherwise | |
915 | * if there are mutiple queues in the group, each can dispatch | |
916 | * a single request on seeky media and cause lots of seek time | |
917 | * and group will never know it. | |
918 | */ | |
919 | slice_used = max_t(unsigned, (jiffies - cfqq->dispatch_start), | |
920 | 1); | |
921 | } else { | |
922 | slice_used = jiffies - cfqq->slice_start; | |
f75edf2d VG |
923 | if (slice_used > cfqq->allocated_slice) |
924 | slice_used = cfqq->allocated_slice; | |
dae739eb VG |
925 | } |
926 | ||
dae739eb VG |
927 | return slice_used; |
928 | } | |
929 | ||
930 | static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg, | |
e5ff082e | 931 | struct cfq_queue *cfqq) |
dae739eb VG |
932 | { |
933 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
02b35081 | 934 | unsigned int used_sl, charge; |
f26bd1f0 VG |
935 | int nr_sync = cfqg->nr_cfqq - cfqg_busy_async_queues(cfqd, cfqg) |
936 | - cfqg->service_tree_idle.count; | |
937 | ||
938 | BUG_ON(nr_sync < 0); | |
02b35081 | 939 | used_sl = charge = cfq_cfqq_slice_usage(cfqq); |
dae739eb | 940 | |
02b35081 VG |
941 | if (iops_mode(cfqd)) |
942 | charge = cfqq->slice_dispatch; | |
943 | else if (!cfq_cfqq_sync(cfqq) && !nr_sync) | |
944 | charge = cfqq->allocated_slice; | |
dae739eb VG |
945 | |
946 | /* Can't update vdisktime while group is on service tree */ | |
947 | cfq_rb_erase(&cfqg->rb_node, st); | |
02b35081 | 948 | cfqg->vdisktime += cfq_scale_slice(charge, cfqg); |
dae739eb VG |
949 | __cfq_group_service_tree_add(st, cfqg); |
950 | ||
951 | /* This group is being expired. Save the context */ | |
952 | if (time_after(cfqd->workload_expires, jiffies)) { | |
953 | cfqg->saved_workload_slice = cfqd->workload_expires | |
954 | - jiffies; | |
955 | cfqg->saved_workload = cfqd->serving_type; | |
956 | cfqg->saved_serving_prio = cfqd->serving_prio; | |
957 | } else | |
958 | cfqg->saved_workload_slice = 0; | |
2868ef7b VG |
959 | |
960 | cfq_log_cfqg(cfqd, cfqg, "served: vt=%llu min_vt=%llu", cfqg->vdisktime, | |
961 | st->min_vdisktime); | |
c4e7893e VG |
962 | cfq_log_cfqq(cfqq->cfqd, cfqq, "sl_used=%u disp=%u charge=%u iops=%u" |
963 | " sect=%u", used_sl, cfqq->slice_dispatch, charge, | |
964 | iops_mode(cfqd), cfqq->nr_sectors); | |
e98ef89b VG |
965 | cfq_blkiocg_update_timeslice_used(&cfqg->blkg, used_sl); |
966 | cfq_blkiocg_set_start_empty_time(&cfqg->blkg); | |
1fa8f6d6 VG |
967 | } |
968 | ||
25fb5169 VG |
969 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
970 | static inline struct cfq_group *cfqg_of_blkg(struct blkio_group *blkg) | |
971 | { | |
972 | if (blkg) | |
973 | return container_of(blkg, struct cfq_group, blkg); | |
974 | return NULL; | |
975 | } | |
976 | ||
fe071437 VG |
977 | void cfq_update_blkio_group_weight(void *key, struct blkio_group *blkg, |
978 | unsigned int weight) | |
f8d461d6 VG |
979 | { |
980 | cfqg_of_blkg(blkg)->weight = weight; | |
981 | } | |
982 | ||
25fb5169 VG |
983 | static struct cfq_group * |
984 | cfq_find_alloc_cfqg(struct cfq_data *cfqd, struct cgroup *cgroup, int create) | |
985 | { | |
986 | struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup); | |
987 | struct cfq_group *cfqg = NULL; | |
988 | void *key = cfqd; | |
989 | int i, j; | |
990 | struct cfq_rb_root *st; | |
22084190 VG |
991 | struct backing_dev_info *bdi = &cfqd->queue->backing_dev_info; |
992 | unsigned int major, minor; | |
25fb5169 | 993 | |
25fb5169 | 994 | cfqg = cfqg_of_blkg(blkiocg_lookup_group(blkcg, key)); |
a74b2ada RB |
995 | if (cfqg && !cfqg->blkg.dev && bdi->dev && dev_name(bdi->dev)) { |
996 | sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor); | |
997 | cfqg->blkg.dev = MKDEV(major, minor); | |
998 | goto done; | |
999 | } | |
25fb5169 VG |
1000 | if (cfqg || !create) |
1001 | goto done; | |
1002 | ||
1003 | cfqg = kzalloc_node(sizeof(*cfqg), GFP_ATOMIC, cfqd->queue->node); | |
1004 | if (!cfqg) | |
1005 | goto done; | |
1006 | ||
25fb5169 VG |
1007 | for_each_cfqg_st(cfqg, i, j, st) |
1008 | *st = CFQ_RB_ROOT; | |
1009 | RB_CLEAR_NODE(&cfqg->rb_node); | |
1010 | ||
b1c35769 VG |
1011 | /* |
1012 | * Take the initial reference that will be released on destroy | |
1013 | * This can be thought of a joint reference by cgroup and | |
1014 | * elevator which will be dropped by either elevator exit | |
1015 | * or cgroup deletion path depending on who is exiting first. | |
1016 | */ | |
329a6781 | 1017 | cfqg->ref = 1; |
b1c35769 | 1018 | |
180be2a0 VG |
1019 | /* |
1020 | * Add group onto cgroup list. It might happen that bdi->dev is | |
b595076a | 1021 | * not initialized yet. Initialize this new group without major |
180be2a0 VG |
1022 | * and minor info and this info will be filled in once a new thread |
1023 | * comes for IO. See code above. | |
1024 | */ | |
1025 | if (bdi->dev) { | |
1026 | sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor); | |
1027 | cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg, (void *)cfqd, | |
22084190 | 1028 | MKDEV(major, minor)); |
180be2a0 VG |
1029 | } else |
1030 | cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg, (void *)cfqd, | |
1031 | 0); | |
1032 | ||
34d0f179 | 1033 | cfqg->weight = blkcg_get_weight(blkcg, cfqg->blkg.dev); |
25fb5169 VG |
1034 | |
1035 | /* Add group on cfqd list */ | |
1036 | hlist_add_head(&cfqg->cfqd_node, &cfqd->cfqg_list); | |
1037 | ||
1038 | done: | |
25fb5169 VG |
1039 | return cfqg; |
1040 | } | |
1041 | ||
1042 | /* | |
1043 | * Search for the cfq group current task belongs to. If create = 1, then also | |
1044 | * create the cfq group if it does not exist. request_queue lock must be held. | |
1045 | */ | |
1046 | static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd, int create) | |
1047 | { | |
1048 | struct cgroup *cgroup; | |
1049 | struct cfq_group *cfqg = NULL; | |
1050 | ||
1051 | rcu_read_lock(); | |
1052 | cgroup = task_cgroup(current, blkio_subsys_id); | |
1053 | cfqg = cfq_find_alloc_cfqg(cfqd, cgroup, create); | |
1054 | if (!cfqg && create) | |
1055 | cfqg = &cfqd->root_group; | |
1056 | rcu_read_unlock(); | |
1057 | return cfqg; | |
1058 | } | |
1059 | ||
7f1dc8a2 VG |
1060 | static inline struct cfq_group *cfq_ref_get_cfqg(struct cfq_group *cfqg) |
1061 | { | |
329a6781 | 1062 | cfqg->ref++; |
7f1dc8a2 VG |
1063 | return cfqg; |
1064 | } | |
1065 | ||
25fb5169 VG |
1066 | static void cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) |
1067 | { | |
1068 | /* Currently, all async queues are mapped to root group */ | |
1069 | if (!cfq_cfqq_sync(cfqq)) | |
1070 | cfqg = &cfqq->cfqd->root_group; | |
1071 | ||
1072 | cfqq->cfqg = cfqg; | |
b1c35769 | 1073 | /* cfqq reference on cfqg */ |
329a6781 | 1074 | cfqq->cfqg->ref++; |
b1c35769 VG |
1075 | } |
1076 | ||
1077 | static void cfq_put_cfqg(struct cfq_group *cfqg) | |
1078 | { | |
1079 | struct cfq_rb_root *st; | |
1080 | int i, j; | |
1081 | ||
329a6781 SL |
1082 | BUG_ON(cfqg->ref <= 0); |
1083 | cfqg->ref--; | |
1084 | if (cfqg->ref) | |
b1c35769 VG |
1085 | return; |
1086 | for_each_cfqg_st(cfqg, i, j, st) | |
b54ce60e | 1087 | BUG_ON(!RB_EMPTY_ROOT(&st->rb)); |
b1c35769 VG |
1088 | kfree(cfqg); |
1089 | } | |
1090 | ||
1091 | static void cfq_destroy_cfqg(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
1092 | { | |
1093 | /* Something wrong if we are trying to remove same group twice */ | |
1094 | BUG_ON(hlist_unhashed(&cfqg->cfqd_node)); | |
1095 | ||
1096 | hlist_del_init(&cfqg->cfqd_node); | |
1097 | ||
1098 | /* | |
1099 | * Put the reference taken at the time of creation so that when all | |
1100 | * queues are gone, group can be destroyed. | |
1101 | */ | |
1102 | cfq_put_cfqg(cfqg); | |
1103 | } | |
1104 | ||
1105 | static void cfq_release_cfq_groups(struct cfq_data *cfqd) | |
1106 | { | |
1107 | struct hlist_node *pos, *n; | |
1108 | struct cfq_group *cfqg; | |
1109 | ||
1110 | hlist_for_each_entry_safe(cfqg, pos, n, &cfqd->cfqg_list, cfqd_node) { | |
1111 | /* | |
1112 | * If cgroup removal path got to blk_group first and removed | |
1113 | * it from cgroup list, then it will take care of destroying | |
1114 | * cfqg also. | |
1115 | */ | |
e98ef89b | 1116 | if (!cfq_blkiocg_del_blkio_group(&cfqg->blkg)) |
b1c35769 VG |
1117 | cfq_destroy_cfqg(cfqd, cfqg); |
1118 | } | |
25fb5169 | 1119 | } |
b1c35769 VG |
1120 | |
1121 | /* | |
1122 | * Blk cgroup controller notification saying that blkio_group object is being | |
1123 | * delinked as associated cgroup object is going away. That also means that | |
1124 | * no new IO will come in this group. So get rid of this group as soon as | |
1125 | * any pending IO in the group is finished. | |
1126 | * | |
1127 | * This function is called under rcu_read_lock(). key is the rcu protected | |
1128 | * pointer. That means "key" is a valid cfq_data pointer as long as we are rcu | |
1129 | * read lock. | |
1130 | * | |
1131 | * "key" was fetched from blkio_group under blkio_cgroup->lock. That means | |
1132 | * it should not be NULL as even if elevator was exiting, cgroup deltion | |
1133 | * path got to it first. | |
1134 | */ | |
1135 | void cfq_unlink_blkio_group(void *key, struct blkio_group *blkg) | |
1136 | { | |
1137 | unsigned long flags; | |
1138 | struct cfq_data *cfqd = key; | |
1139 | ||
1140 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
1141 | cfq_destroy_cfqg(cfqd, cfqg_of_blkg(blkg)); | |
1142 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
1143 | } | |
1144 | ||
25fb5169 VG |
1145 | #else /* GROUP_IOSCHED */ |
1146 | static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd, int create) | |
1147 | { | |
1148 | return &cfqd->root_group; | |
1149 | } | |
7f1dc8a2 VG |
1150 | |
1151 | static inline struct cfq_group *cfq_ref_get_cfqg(struct cfq_group *cfqg) | |
1152 | { | |
50eaeb32 | 1153 | return cfqg; |
7f1dc8a2 VG |
1154 | } |
1155 | ||
25fb5169 VG |
1156 | static inline void |
1157 | cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) { | |
1158 | cfqq->cfqg = cfqg; | |
1159 | } | |
1160 | ||
b1c35769 VG |
1161 | static void cfq_release_cfq_groups(struct cfq_data *cfqd) {} |
1162 | static inline void cfq_put_cfqg(struct cfq_group *cfqg) {} | |
1163 | ||
25fb5169 VG |
1164 | #endif /* GROUP_IOSCHED */ |
1165 | ||
498d3aa2 | 1166 | /* |
c0324a02 | 1167 | * The cfqd->service_trees holds all pending cfq_queue's that have |
498d3aa2 JA |
1168 | * requests waiting to be processed. It is sorted in the order that |
1169 | * we will service the queues. | |
1170 | */ | |
a36e71f9 | 1171 | static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
a6151c3a | 1172 | bool add_front) |
d9e7620e | 1173 | { |
0871714e JA |
1174 | struct rb_node **p, *parent; |
1175 | struct cfq_queue *__cfqq; | |
d9e7620e | 1176 | unsigned long rb_key; |
c0324a02 | 1177 | struct cfq_rb_root *service_tree; |
498d3aa2 | 1178 | int left; |
dae739eb | 1179 | int new_cfqq = 1; |
ae30c286 VG |
1180 | int group_changed = 0; |
1181 | ||
1182 | #ifdef CONFIG_CFQ_GROUP_IOSCHED | |
1183 | if (!cfqd->cfq_group_isolation | |
1184 | && cfqq_type(cfqq) == SYNC_NOIDLE_WORKLOAD | |
1185 | && cfqq->cfqg && cfqq->cfqg != &cfqd->root_group) { | |
1186 | /* Move this cfq to root group */ | |
1187 | cfq_log_cfqq(cfqd, cfqq, "moving to root group"); | |
1188 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) | |
1189 | cfq_group_service_tree_del(cfqd, cfqq->cfqg); | |
1190 | cfqq->orig_cfqg = cfqq->cfqg; | |
1191 | cfqq->cfqg = &cfqd->root_group; | |
329a6781 | 1192 | cfqd->root_group.ref++; |
ae30c286 VG |
1193 | group_changed = 1; |
1194 | } else if (!cfqd->cfq_group_isolation | |
1195 | && cfqq_type(cfqq) == SYNC_WORKLOAD && cfqq->orig_cfqg) { | |
1196 | /* cfqq is sequential now needs to go to its original group */ | |
1197 | BUG_ON(cfqq->cfqg != &cfqd->root_group); | |
1198 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) | |
1199 | cfq_group_service_tree_del(cfqd, cfqq->cfqg); | |
1200 | cfq_put_cfqg(cfqq->cfqg); | |
1201 | cfqq->cfqg = cfqq->orig_cfqg; | |
1202 | cfqq->orig_cfqg = NULL; | |
1203 | group_changed = 1; | |
1204 | cfq_log_cfqq(cfqd, cfqq, "moved to origin group"); | |
1205 | } | |
1206 | #endif | |
d9e7620e | 1207 | |
cdb16e8f | 1208 | service_tree = service_tree_for(cfqq->cfqg, cfqq_prio(cfqq), |
65b32a57 | 1209 | cfqq_type(cfqq)); |
0871714e JA |
1210 | if (cfq_class_idle(cfqq)) { |
1211 | rb_key = CFQ_IDLE_DELAY; | |
aa6f6a3d | 1212 | parent = rb_last(&service_tree->rb); |
0871714e JA |
1213 | if (parent && parent != &cfqq->rb_node) { |
1214 | __cfqq = rb_entry(parent, struct cfq_queue, rb_node); | |
1215 | rb_key += __cfqq->rb_key; | |
1216 | } else | |
1217 | rb_key += jiffies; | |
1218 | } else if (!add_front) { | |
b9c8946b JA |
1219 | /* |
1220 | * Get our rb key offset. Subtract any residual slice | |
1221 | * value carried from last service. A negative resid | |
1222 | * count indicates slice overrun, and this should position | |
1223 | * the next service time further away in the tree. | |
1224 | */ | |
edd75ffd | 1225 | rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies; |
b9c8946b | 1226 | rb_key -= cfqq->slice_resid; |
edd75ffd | 1227 | cfqq->slice_resid = 0; |
48e025e6 CZ |
1228 | } else { |
1229 | rb_key = -HZ; | |
aa6f6a3d | 1230 | __cfqq = cfq_rb_first(service_tree); |
48e025e6 CZ |
1231 | rb_key += __cfqq ? __cfqq->rb_key : jiffies; |
1232 | } | |
1da177e4 | 1233 | |
d9e7620e | 1234 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) { |
dae739eb | 1235 | new_cfqq = 0; |
99f9628a | 1236 | /* |
d9e7620e | 1237 | * same position, nothing more to do |
99f9628a | 1238 | */ |
c0324a02 CZ |
1239 | if (rb_key == cfqq->rb_key && |
1240 | cfqq->service_tree == service_tree) | |
d9e7620e | 1241 | return; |
1da177e4 | 1242 | |
aa6f6a3d CZ |
1243 | cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree); |
1244 | cfqq->service_tree = NULL; | |
1da177e4 | 1245 | } |
d9e7620e | 1246 | |
498d3aa2 | 1247 | left = 1; |
0871714e | 1248 | parent = NULL; |
aa6f6a3d CZ |
1249 | cfqq->service_tree = service_tree; |
1250 | p = &service_tree->rb.rb_node; | |
d9e7620e | 1251 | while (*p) { |
67060e37 | 1252 | struct rb_node **n; |
cc09e299 | 1253 | |
d9e7620e JA |
1254 | parent = *p; |
1255 | __cfqq = rb_entry(parent, struct cfq_queue, rb_node); | |
1256 | ||
0c534e0a | 1257 | /* |
c0324a02 | 1258 | * sort by key, that represents service time. |
0c534e0a | 1259 | */ |
c0324a02 | 1260 | if (time_before(rb_key, __cfqq->rb_key)) |
67060e37 | 1261 | n = &(*p)->rb_left; |
c0324a02 | 1262 | else { |
67060e37 | 1263 | n = &(*p)->rb_right; |
cc09e299 | 1264 | left = 0; |
c0324a02 | 1265 | } |
67060e37 JA |
1266 | |
1267 | p = n; | |
d9e7620e JA |
1268 | } |
1269 | ||
cc09e299 | 1270 | if (left) |
aa6f6a3d | 1271 | service_tree->left = &cfqq->rb_node; |
cc09e299 | 1272 | |
d9e7620e JA |
1273 | cfqq->rb_key = rb_key; |
1274 | rb_link_node(&cfqq->rb_node, parent, p); | |
aa6f6a3d CZ |
1275 | rb_insert_color(&cfqq->rb_node, &service_tree->rb); |
1276 | service_tree->count++; | |
ae30c286 | 1277 | if ((add_front || !new_cfqq) && !group_changed) |
dae739eb | 1278 | return; |
1fa8f6d6 | 1279 | cfq_group_service_tree_add(cfqd, cfqq->cfqg); |
1da177e4 LT |
1280 | } |
1281 | ||
a36e71f9 | 1282 | static struct cfq_queue * |
f2d1f0ae JA |
1283 | cfq_prio_tree_lookup(struct cfq_data *cfqd, struct rb_root *root, |
1284 | sector_t sector, struct rb_node **ret_parent, | |
1285 | struct rb_node ***rb_link) | |
a36e71f9 | 1286 | { |
a36e71f9 JA |
1287 | struct rb_node **p, *parent; |
1288 | struct cfq_queue *cfqq = NULL; | |
1289 | ||
1290 | parent = NULL; | |
1291 | p = &root->rb_node; | |
1292 | while (*p) { | |
1293 | struct rb_node **n; | |
1294 | ||
1295 | parent = *p; | |
1296 | cfqq = rb_entry(parent, struct cfq_queue, p_node); | |
1297 | ||
1298 | /* | |
1299 | * Sort strictly based on sector. Smallest to the left, | |
1300 | * largest to the right. | |
1301 | */ | |
2e46e8b2 | 1302 | if (sector > blk_rq_pos(cfqq->next_rq)) |
a36e71f9 | 1303 | n = &(*p)->rb_right; |
2e46e8b2 | 1304 | else if (sector < blk_rq_pos(cfqq->next_rq)) |
a36e71f9 JA |
1305 | n = &(*p)->rb_left; |
1306 | else | |
1307 | break; | |
1308 | p = n; | |
3ac6c9f8 | 1309 | cfqq = NULL; |
a36e71f9 JA |
1310 | } |
1311 | ||
1312 | *ret_parent = parent; | |
1313 | if (rb_link) | |
1314 | *rb_link = p; | |
3ac6c9f8 | 1315 | return cfqq; |
a36e71f9 JA |
1316 | } |
1317 | ||
1318 | static void cfq_prio_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1319 | { | |
a36e71f9 JA |
1320 | struct rb_node **p, *parent; |
1321 | struct cfq_queue *__cfqq; | |
1322 | ||
f2d1f0ae JA |
1323 | if (cfqq->p_root) { |
1324 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
1325 | cfqq->p_root = NULL; | |
1326 | } | |
a36e71f9 JA |
1327 | |
1328 | if (cfq_class_idle(cfqq)) | |
1329 | return; | |
1330 | if (!cfqq->next_rq) | |
1331 | return; | |
1332 | ||
f2d1f0ae | 1333 | cfqq->p_root = &cfqd->prio_trees[cfqq->org_ioprio]; |
2e46e8b2 TH |
1334 | __cfqq = cfq_prio_tree_lookup(cfqd, cfqq->p_root, |
1335 | blk_rq_pos(cfqq->next_rq), &parent, &p); | |
3ac6c9f8 JA |
1336 | if (!__cfqq) { |
1337 | rb_link_node(&cfqq->p_node, parent, p); | |
f2d1f0ae JA |
1338 | rb_insert_color(&cfqq->p_node, cfqq->p_root); |
1339 | } else | |
1340 | cfqq->p_root = NULL; | |
a36e71f9 JA |
1341 | } |
1342 | ||
498d3aa2 JA |
1343 | /* |
1344 | * Update cfqq's position in the service tree. | |
1345 | */ | |
edd75ffd | 1346 | static void cfq_resort_rr_list(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
6d048f53 | 1347 | { |
6d048f53 JA |
1348 | /* |
1349 | * Resorting requires the cfqq to be on the RR list already. | |
1350 | */ | |
a36e71f9 | 1351 | if (cfq_cfqq_on_rr(cfqq)) { |
edd75ffd | 1352 | cfq_service_tree_add(cfqd, cfqq, 0); |
a36e71f9 JA |
1353 | cfq_prio_tree_add(cfqd, cfqq); |
1354 | } | |
6d048f53 JA |
1355 | } |
1356 | ||
1da177e4 LT |
1357 | /* |
1358 | * add to busy list of queues for service, trying to be fair in ordering | |
22e2c507 | 1359 | * the pending list according to last request service |
1da177e4 | 1360 | */ |
febffd61 | 1361 | static void cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 1362 | { |
7b679138 | 1363 | cfq_log_cfqq(cfqd, cfqq, "add_to_rr"); |
3b18152c JA |
1364 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
1365 | cfq_mark_cfqq_on_rr(cfqq); | |
1da177e4 LT |
1366 | cfqd->busy_queues++; |
1367 | ||
edd75ffd | 1368 | cfq_resort_rr_list(cfqd, cfqq); |
1da177e4 LT |
1369 | } |
1370 | ||
498d3aa2 JA |
1371 | /* |
1372 | * Called when the cfqq no longer has requests pending, remove it from | |
1373 | * the service tree. | |
1374 | */ | |
febffd61 | 1375 | static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 1376 | { |
7b679138 | 1377 | cfq_log_cfqq(cfqd, cfqq, "del_from_rr"); |
3b18152c JA |
1378 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
1379 | cfq_clear_cfqq_on_rr(cfqq); | |
1da177e4 | 1380 | |
aa6f6a3d CZ |
1381 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) { |
1382 | cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree); | |
1383 | cfqq->service_tree = NULL; | |
1384 | } | |
f2d1f0ae JA |
1385 | if (cfqq->p_root) { |
1386 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
1387 | cfqq->p_root = NULL; | |
1388 | } | |
d9e7620e | 1389 | |
1fa8f6d6 | 1390 | cfq_group_service_tree_del(cfqd, cfqq->cfqg); |
1da177e4 LT |
1391 | BUG_ON(!cfqd->busy_queues); |
1392 | cfqd->busy_queues--; | |
1393 | } | |
1394 | ||
1395 | /* | |
1396 | * rb tree support functions | |
1397 | */ | |
febffd61 | 1398 | static void cfq_del_rq_rb(struct request *rq) |
1da177e4 | 1399 | { |
5e705374 | 1400 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
5e705374 | 1401 | const int sync = rq_is_sync(rq); |
1da177e4 | 1402 | |
b4878f24 JA |
1403 | BUG_ON(!cfqq->queued[sync]); |
1404 | cfqq->queued[sync]--; | |
1da177e4 | 1405 | |
5e705374 | 1406 | elv_rb_del(&cfqq->sort_list, rq); |
1da177e4 | 1407 | |
f04a6424 VG |
1408 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) { |
1409 | /* | |
1410 | * Queue will be deleted from service tree when we actually | |
1411 | * expire it later. Right now just remove it from prio tree | |
1412 | * as it is empty. | |
1413 | */ | |
1414 | if (cfqq->p_root) { | |
1415 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
1416 | cfqq->p_root = NULL; | |
1417 | } | |
1418 | } | |
1da177e4 LT |
1419 | } |
1420 | ||
5e705374 | 1421 | static void cfq_add_rq_rb(struct request *rq) |
1da177e4 | 1422 | { |
5e705374 | 1423 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
1da177e4 | 1424 | struct cfq_data *cfqd = cfqq->cfqd; |
a36e71f9 | 1425 | struct request *__alias, *prev; |
1da177e4 | 1426 | |
5380a101 | 1427 | cfqq->queued[rq_is_sync(rq)]++; |
1da177e4 LT |
1428 | |
1429 | /* | |
1430 | * looks a little odd, but the first insert might return an alias. | |
1431 | * if that happens, put the alias on the dispatch list | |
1432 | */ | |
21183b07 | 1433 | while ((__alias = elv_rb_add(&cfqq->sort_list, rq)) != NULL) |
5e705374 | 1434 | cfq_dispatch_insert(cfqd->queue, __alias); |
5fccbf61 JA |
1435 | |
1436 | if (!cfq_cfqq_on_rr(cfqq)) | |
1437 | cfq_add_cfqq_rr(cfqd, cfqq); | |
5044eed4 JA |
1438 | |
1439 | /* | |
1440 | * check if this request is a better next-serve candidate | |
1441 | */ | |
a36e71f9 | 1442 | prev = cfqq->next_rq; |
cf7c25cf | 1443 | cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq, cfqd->last_position); |
a36e71f9 JA |
1444 | |
1445 | /* | |
1446 | * adjust priority tree position, if ->next_rq changes | |
1447 | */ | |
1448 | if (prev != cfqq->next_rq) | |
1449 | cfq_prio_tree_add(cfqd, cfqq); | |
1450 | ||
5044eed4 | 1451 | BUG_ON(!cfqq->next_rq); |
1da177e4 LT |
1452 | } |
1453 | ||
febffd61 | 1454 | static void cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq) |
1da177e4 | 1455 | { |
5380a101 JA |
1456 | elv_rb_del(&cfqq->sort_list, rq); |
1457 | cfqq->queued[rq_is_sync(rq)]--; | |
e98ef89b VG |
1458 | cfq_blkiocg_update_io_remove_stats(&(RQ_CFQG(rq))->blkg, |
1459 | rq_data_dir(rq), rq_is_sync(rq)); | |
5e705374 | 1460 | cfq_add_rq_rb(rq); |
e98ef89b | 1461 | cfq_blkiocg_update_io_add_stats(&(RQ_CFQG(rq))->blkg, |
7f1dc8a2 VG |
1462 | &cfqq->cfqd->serving_group->blkg, rq_data_dir(rq), |
1463 | rq_is_sync(rq)); | |
1da177e4 LT |
1464 | } |
1465 | ||
206dc69b JA |
1466 | static struct request * |
1467 | cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio) | |
1da177e4 | 1468 | { |
206dc69b | 1469 | struct task_struct *tsk = current; |
91fac317 | 1470 | struct cfq_io_context *cic; |
206dc69b | 1471 | struct cfq_queue *cfqq; |
1da177e4 | 1472 | |
4ac845a2 | 1473 | cic = cfq_cic_lookup(cfqd, tsk->io_context); |
91fac317 VT |
1474 | if (!cic) |
1475 | return NULL; | |
1476 | ||
1477 | cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); | |
89850f7e JA |
1478 | if (cfqq) { |
1479 | sector_t sector = bio->bi_sector + bio_sectors(bio); | |
1480 | ||
21183b07 | 1481 | return elv_rb_find(&cfqq->sort_list, sector); |
89850f7e | 1482 | } |
1da177e4 | 1483 | |
1da177e4 LT |
1484 | return NULL; |
1485 | } | |
1486 | ||
165125e1 | 1487 | static void cfq_activate_request(struct request_queue *q, struct request *rq) |
1da177e4 | 1488 | { |
22e2c507 | 1489 | struct cfq_data *cfqd = q->elevator->elevator_data; |
3b18152c | 1490 | |
53c583d2 | 1491 | cfqd->rq_in_driver++; |
7b679138 | 1492 | cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "activate rq, drv=%d", |
53c583d2 | 1493 | cfqd->rq_in_driver); |
25776e35 | 1494 | |
5b93629b | 1495 | cfqd->last_position = blk_rq_pos(rq) + blk_rq_sectors(rq); |
1da177e4 LT |
1496 | } |
1497 | ||
165125e1 | 1498 | static void cfq_deactivate_request(struct request_queue *q, struct request *rq) |
1da177e4 | 1499 | { |
b4878f24 JA |
1500 | struct cfq_data *cfqd = q->elevator->elevator_data; |
1501 | ||
53c583d2 CZ |
1502 | WARN_ON(!cfqd->rq_in_driver); |
1503 | cfqd->rq_in_driver--; | |
7b679138 | 1504 | cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "deactivate rq, drv=%d", |
53c583d2 | 1505 | cfqd->rq_in_driver); |
1da177e4 LT |
1506 | } |
1507 | ||
b4878f24 | 1508 | static void cfq_remove_request(struct request *rq) |
1da177e4 | 1509 | { |
5e705374 | 1510 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
21183b07 | 1511 | |
5e705374 JA |
1512 | if (cfqq->next_rq == rq) |
1513 | cfqq->next_rq = cfq_find_next_rq(cfqq->cfqd, cfqq, rq); | |
1da177e4 | 1514 | |
b4878f24 | 1515 | list_del_init(&rq->queuelist); |
5e705374 | 1516 | cfq_del_rq_rb(rq); |
374f84ac | 1517 | |
45333d5a | 1518 | cfqq->cfqd->rq_queued--; |
e98ef89b VG |
1519 | cfq_blkiocg_update_io_remove_stats(&(RQ_CFQG(rq))->blkg, |
1520 | rq_data_dir(rq), rq_is_sync(rq)); | |
7b6d91da | 1521 | if (rq->cmd_flags & REQ_META) { |
374f84ac JA |
1522 | WARN_ON(!cfqq->meta_pending); |
1523 | cfqq->meta_pending--; | |
1524 | } | |
1da177e4 LT |
1525 | } |
1526 | ||
165125e1 JA |
1527 | static int cfq_merge(struct request_queue *q, struct request **req, |
1528 | struct bio *bio) | |
1da177e4 LT |
1529 | { |
1530 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1531 | struct request *__rq; | |
1da177e4 | 1532 | |
206dc69b | 1533 | __rq = cfq_find_rq_fmerge(cfqd, bio); |
22e2c507 | 1534 | if (__rq && elv_rq_merge_ok(__rq, bio)) { |
9817064b JA |
1535 | *req = __rq; |
1536 | return ELEVATOR_FRONT_MERGE; | |
1da177e4 LT |
1537 | } |
1538 | ||
1539 | return ELEVATOR_NO_MERGE; | |
1da177e4 LT |
1540 | } |
1541 | ||
165125e1 | 1542 | static void cfq_merged_request(struct request_queue *q, struct request *req, |
21183b07 | 1543 | int type) |
1da177e4 | 1544 | { |
21183b07 | 1545 | if (type == ELEVATOR_FRONT_MERGE) { |
5e705374 | 1546 | struct cfq_queue *cfqq = RQ_CFQQ(req); |
1da177e4 | 1547 | |
5e705374 | 1548 | cfq_reposition_rq_rb(cfqq, req); |
1da177e4 | 1549 | } |
1da177e4 LT |
1550 | } |
1551 | ||
812d4026 DS |
1552 | static void cfq_bio_merged(struct request_queue *q, struct request *req, |
1553 | struct bio *bio) | |
1554 | { | |
e98ef89b VG |
1555 | cfq_blkiocg_update_io_merged_stats(&(RQ_CFQG(req))->blkg, |
1556 | bio_data_dir(bio), cfq_bio_sync(bio)); | |
812d4026 DS |
1557 | } |
1558 | ||
1da177e4 | 1559 | static void |
165125e1 | 1560 | cfq_merged_requests(struct request_queue *q, struct request *rq, |
1da177e4 LT |
1561 | struct request *next) |
1562 | { | |
cf7c25cf | 1563 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 JA |
1564 | /* |
1565 | * reposition in fifo if next is older than rq | |
1566 | */ | |
1567 | if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && | |
30996f40 | 1568 | time_before(rq_fifo_time(next), rq_fifo_time(rq))) { |
22e2c507 | 1569 | list_move(&rq->queuelist, &next->queuelist); |
30996f40 JA |
1570 | rq_set_fifo_time(rq, rq_fifo_time(next)); |
1571 | } | |
22e2c507 | 1572 | |
cf7c25cf CZ |
1573 | if (cfqq->next_rq == next) |
1574 | cfqq->next_rq = rq; | |
b4878f24 | 1575 | cfq_remove_request(next); |
e98ef89b VG |
1576 | cfq_blkiocg_update_io_merged_stats(&(RQ_CFQG(rq))->blkg, |
1577 | rq_data_dir(next), rq_is_sync(next)); | |
22e2c507 JA |
1578 | } |
1579 | ||
165125e1 | 1580 | static int cfq_allow_merge(struct request_queue *q, struct request *rq, |
da775265 JA |
1581 | struct bio *bio) |
1582 | { | |
1583 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
91fac317 | 1584 | struct cfq_io_context *cic; |
da775265 | 1585 | struct cfq_queue *cfqq; |
da775265 JA |
1586 | |
1587 | /* | |
ec8acb69 | 1588 | * Disallow merge of a sync bio into an async request. |
da775265 | 1589 | */ |
91fac317 | 1590 | if (cfq_bio_sync(bio) && !rq_is_sync(rq)) |
a6151c3a | 1591 | return false; |
da775265 JA |
1592 | |
1593 | /* | |
719d3402 JA |
1594 | * Lookup the cfqq that this bio will be queued with. Allow |
1595 | * merge only if rq is queued there. | |
da775265 | 1596 | */ |
4ac845a2 | 1597 | cic = cfq_cic_lookup(cfqd, current->io_context); |
91fac317 | 1598 | if (!cic) |
a6151c3a | 1599 | return false; |
719d3402 | 1600 | |
91fac317 | 1601 | cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); |
a6151c3a | 1602 | return cfqq == RQ_CFQQ(rq); |
da775265 JA |
1603 | } |
1604 | ||
812df48d DS |
1605 | static inline void cfq_del_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1606 | { | |
1607 | del_timer(&cfqd->idle_slice_timer); | |
e98ef89b | 1608 | cfq_blkiocg_update_idle_time_stats(&cfqq->cfqg->blkg); |
812df48d DS |
1609 | } |
1610 | ||
febffd61 JA |
1611 | static void __cfq_set_active_queue(struct cfq_data *cfqd, |
1612 | struct cfq_queue *cfqq) | |
22e2c507 JA |
1613 | { |
1614 | if (cfqq) { | |
b1ffe737 DS |
1615 | cfq_log_cfqq(cfqd, cfqq, "set_active wl_prio:%d wl_type:%d", |
1616 | cfqd->serving_prio, cfqd->serving_type); | |
e98ef89b | 1617 | cfq_blkiocg_update_avg_queue_size_stats(&cfqq->cfqg->blkg); |
dae739eb VG |
1618 | cfqq->slice_start = 0; |
1619 | cfqq->dispatch_start = jiffies; | |
f75edf2d | 1620 | cfqq->allocated_slice = 0; |
22e2c507 | 1621 | cfqq->slice_end = 0; |
2f5cb738 | 1622 | cfqq->slice_dispatch = 0; |
c4e7893e | 1623 | cfqq->nr_sectors = 0; |
2f5cb738 | 1624 | |
2f5cb738 | 1625 | cfq_clear_cfqq_wait_request(cfqq); |
b029195d | 1626 | cfq_clear_cfqq_must_dispatch(cfqq); |
3b18152c JA |
1627 | cfq_clear_cfqq_must_alloc_slice(cfqq); |
1628 | cfq_clear_cfqq_fifo_expire(cfqq); | |
44f7c160 | 1629 | cfq_mark_cfqq_slice_new(cfqq); |
2f5cb738 | 1630 | |
812df48d | 1631 | cfq_del_timer(cfqd, cfqq); |
22e2c507 JA |
1632 | } |
1633 | ||
1634 | cfqd->active_queue = cfqq; | |
1635 | } | |
1636 | ||
7b14e3b5 JA |
1637 | /* |
1638 | * current cfqq expired its slice (or was too idle), select new one | |
1639 | */ | |
1640 | static void | |
1641 | __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
e5ff082e | 1642 | bool timed_out) |
7b14e3b5 | 1643 | { |
7b679138 JA |
1644 | cfq_log_cfqq(cfqd, cfqq, "slice expired t=%d", timed_out); |
1645 | ||
7b14e3b5 | 1646 | if (cfq_cfqq_wait_request(cfqq)) |
812df48d | 1647 | cfq_del_timer(cfqd, cfqq); |
7b14e3b5 | 1648 | |
7b14e3b5 | 1649 | cfq_clear_cfqq_wait_request(cfqq); |
f75edf2d | 1650 | cfq_clear_cfqq_wait_busy(cfqq); |
7b14e3b5 | 1651 | |
ae54abed SL |
1652 | /* |
1653 | * If this cfqq is shared between multiple processes, check to | |
1654 | * make sure that those processes are still issuing I/Os within | |
1655 | * the mean seek distance. If not, it may be time to break the | |
1656 | * queues apart again. | |
1657 | */ | |
1658 | if (cfq_cfqq_coop(cfqq) && CFQQ_SEEKY(cfqq)) | |
1659 | cfq_mark_cfqq_split_coop(cfqq); | |
1660 | ||
7b14e3b5 | 1661 | /* |
6084cdda | 1662 | * store what was left of this slice, if the queue idled/timed out |
7b14e3b5 | 1663 | */ |
7b679138 | 1664 | if (timed_out && !cfq_cfqq_slice_new(cfqq)) { |
c5b680f3 | 1665 | cfqq->slice_resid = cfqq->slice_end - jiffies; |
7b679138 JA |
1666 | cfq_log_cfqq(cfqd, cfqq, "resid=%ld", cfqq->slice_resid); |
1667 | } | |
7b14e3b5 | 1668 | |
e5ff082e | 1669 | cfq_group_served(cfqd, cfqq->cfqg, cfqq); |
dae739eb | 1670 | |
f04a6424 VG |
1671 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) |
1672 | cfq_del_cfqq_rr(cfqd, cfqq); | |
1673 | ||
edd75ffd | 1674 | cfq_resort_rr_list(cfqd, cfqq); |
7b14e3b5 JA |
1675 | |
1676 | if (cfqq == cfqd->active_queue) | |
1677 | cfqd->active_queue = NULL; | |
1678 | ||
1679 | if (cfqd->active_cic) { | |
1680 | put_io_context(cfqd->active_cic->ioc); | |
1681 | cfqd->active_cic = NULL; | |
1682 | } | |
7b14e3b5 JA |
1683 | } |
1684 | ||
e5ff082e | 1685 | static inline void cfq_slice_expired(struct cfq_data *cfqd, bool timed_out) |
7b14e3b5 JA |
1686 | { |
1687 | struct cfq_queue *cfqq = cfqd->active_queue; | |
1688 | ||
1689 | if (cfqq) | |
e5ff082e | 1690 | __cfq_slice_expired(cfqd, cfqq, timed_out); |
7b14e3b5 JA |
1691 | } |
1692 | ||
498d3aa2 JA |
1693 | /* |
1694 | * Get next queue for service. Unless we have a queue preemption, | |
1695 | * we'll simply select the first cfqq in the service tree. | |
1696 | */ | |
6d048f53 | 1697 | static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd) |
22e2c507 | 1698 | { |
c0324a02 | 1699 | struct cfq_rb_root *service_tree = |
cdb16e8f | 1700 | service_tree_for(cfqd->serving_group, cfqd->serving_prio, |
65b32a57 | 1701 | cfqd->serving_type); |
d9e7620e | 1702 | |
f04a6424 VG |
1703 | if (!cfqd->rq_queued) |
1704 | return NULL; | |
1705 | ||
1fa8f6d6 VG |
1706 | /* There is nothing to dispatch */ |
1707 | if (!service_tree) | |
1708 | return NULL; | |
c0324a02 CZ |
1709 | if (RB_EMPTY_ROOT(&service_tree->rb)) |
1710 | return NULL; | |
1711 | return cfq_rb_first(service_tree); | |
6d048f53 JA |
1712 | } |
1713 | ||
f04a6424 VG |
1714 | static struct cfq_queue *cfq_get_next_queue_forced(struct cfq_data *cfqd) |
1715 | { | |
25fb5169 | 1716 | struct cfq_group *cfqg; |
f04a6424 VG |
1717 | struct cfq_queue *cfqq; |
1718 | int i, j; | |
1719 | struct cfq_rb_root *st; | |
1720 | ||
1721 | if (!cfqd->rq_queued) | |
1722 | return NULL; | |
1723 | ||
25fb5169 VG |
1724 | cfqg = cfq_get_next_cfqg(cfqd); |
1725 | if (!cfqg) | |
1726 | return NULL; | |
1727 | ||
f04a6424 VG |
1728 | for_each_cfqg_st(cfqg, i, j, st) |
1729 | if ((cfqq = cfq_rb_first(st)) != NULL) | |
1730 | return cfqq; | |
1731 | return NULL; | |
1732 | } | |
1733 | ||
498d3aa2 JA |
1734 | /* |
1735 | * Get and set a new active queue for service. | |
1736 | */ | |
a36e71f9 JA |
1737 | static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd, |
1738 | struct cfq_queue *cfqq) | |
6d048f53 | 1739 | { |
e00ef799 | 1740 | if (!cfqq) |
a36e71f9 | 1741 | cfqq = cfq_get_next_queue(cfqd); |
6d048f53 | 1742 | |
22e2c507 | 1743 | __cfq_set_active_queue(cfqd, cfqq); |
3b18152c | 1744 | return cfqq; |
22e2c507 JA |
1745 | } |
1746 | ||
d9e7620e JA |
1747 | static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd, |
1748 | struct request *rq) | |
1749 | { | |
83096ebf TH |
1750 | if (blk_rq_pos(rq) >= cfqd->last_position) |
1751 | return blk_rq_pos(rq) - cfqd->last_position; | |
d9e7620e | 1752 | else |
83096ebf | 1753 | return cfqd->last_position - blk_rq_pos(rq); |
d9e7620e JA |
1754 | } |
1755 | ||
b2c18e1e | 1756 | static inline int cfq_rq_close(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
e9ce335d | 1757 | struct request *rq) |
6d048f53 | 1758 | { |
e9ce335d | 1759 | return cfq_dist_from_last(cfqd, rq) <= CFQQ_CLOSE_THR; |
6d048f53 JA |
1760 | } |
1761 | ||
a36e71f9 JA |
1762 | static struct cfq_queue *cfqq_close(struct cfq_data *cfqd, |
1763 | struct cfq_queue *cur_cfqq) | |
1764 | { | |
f2d1f0ae | 1765 | struct rb_root *root = &cfqd->prio_trees[cur_cfqq->org_ioprio]; |
a36e71f9 JA |
1766 | struct rb_node *parent, *node; |
1767 | struct cfq_queue *__cfqq; | |
1768 | sector_t sector = cfqd->last_position; | |
1769 | ||
1770 | if (RB_EMPTY_ROOT(root)) | |
1771 | return NULL; | |
1772 | ||
1773 | /* | |
1774 | * First, if we find a request starting at the end of the last | |
1775 | * request, choose it. | |
1776 | */ | |
f2d1f0ae | 1777 | __cfqq = cfq_prio_tree_lookup(cfqd, root, sector, &parent, NULL); |
a36e71f9 JA |
1778 | if (__cfqq) |
1779 | return __cfqq; | |
1780 | ||
1781 | /* | |
1782 | * If the exact sector wasn't found, the parent of the NULL leaf | |
1783 | * will contain the closest sector. | |
1784 | */ | |
1785 | __cfqq = rb_entry(parent, struct cfq_queue, p_node); | |
e9ce335d | 1786 | if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq)) |
a36e71f9 JA |
1787 | return __cfqq; |
1788 | ||
2e46e8b2 | 1789 | if (blk_rq_pos(__cfqq->next_rq) < sector) |
a36e71f9 JA |
1790 | node = rb_next(&__cfqq->p_node); |
1791 | else | |
1792 | node = rb_prev(&__cfqq->p_node); | |
1793 | if (!node) | |
1794 | return NULL; | |
1795 | ||
1796 | __cfqq = rb_entry(node, struct cfq_queue, p_node); | |
e9ce335d | 1797 | if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq)) |
a36e71f9 JA |
1798 | return __cfqq; |
1799 | ||
1800 | return NULL; | |
1801 | } | |
1802 | ||
1803 | /* | |
1804 | * cfqd - obvious | |
1805 | * cur_cfqq - passed in so that we don't decide that the current queue is | |
1806 | * closely cooperating with itself. | |
1807 | * | |
1808 | * So, basically we're assuming that that cur_cfqq has dispatched at least | |
1809 | * one request, and that cfqd->last_position reflects a position on the disk | |
1810 | * associated with the I/O issued by cur_cfqq. I'm not sure this is a valid | |
1811 | * assumption. | |
1812 | */ | |
1813 | static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd, | |
b3b6d040 | 1814 | struct cfq_queue *cur_cfqq) |
6d048f53 | 1815 | { |
a36e71f9 JA |
1816 | struct cfq_queue *cfqq; |
1817 | ||
39c01b21 DS |
1818 | if (cfq_class_idle(cur_cfqq)) |
1819 | return NULL; | |
e6c5bc73 JM |
1820 | if (!cfq_cfqq_sync(cur_cfqq)) |
1821 | return NULL; | |
1822 | if (CFQQ_SEEKY(cur_cfqq)) | |
1823 | return NULL; | |
1824 | ||
b9d8f4c7 GJ |
1825 | /* |
1826 | * Don't search priority tree if it's the only queue in the group. | |
1827 | */ | |
1828 | if (cur_cfqq->cfqg->nr_cfqq == 1) | |
1829 | return NULL; | |
1830 | ||
6d048f53 | 1831 | /* |
d9e7620e JA |
1832 | * We should notice if some of the queues are cooperating, eg |
1833 | * working closely on the same area of the disk. In that case, | |
1834 | * we can group them together and don't waste time idling. | |
6d048f53 | 1835 | */ |
a36e71f9 JA |
1836 | cfqq = cfqq_close(cfqd, cur_cfqq); |
1837 | if (!cfqq) | |
1838 | return NULL; | |
1839 | ||
8682e1f1 VG |
1840 | /* If new queue belongs to different cfq_group, don't choose it */ |
1841 | if (cur_cfqq->cfqg != cfqq->cfqg) | |
1842 | return NULL; | |
1843 | ||
df5fe3e8 JM |
1844 | /* |
1845 | * It only makes sense to merge sync queues. | |
1846 | */ | |
1847 | if (!cfq_cfqq_sync(cfqq)) | |
1848 | return NULL; | |
e6c5bc73 JM |
1849 | if (CFQQ_SEEKY(cfqq)) |
1850 | return NULL; | |
df5fe3e8 | 1851 | |
c0324a02 CZ |
1852 | /* |
1853 | * Do not merge queues of different priority classes | |
1854 | */ | |
1855 | if (cfq_class_rt(cfqq) != cfq_class_rt(cur_cfqq)) | |
1856 | return NULL; | |
1857 | ||
a36e71f9 | 1858 | return cfqq; |
6d048f53 JA |
1859 | } |
1860 | ||
a6d44e98 CZ |
1861 | /* |
1862 | * Determine whether we should enforce idle window for this queue. | |
1863 | */ | |
1864 | ||
1865 | static bool cfq_should_idle(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1866 | { | |
1867 | enum wl_prio_t prio = cfqq_prio(cfqq); | |
718eee05 | 1868 | struct cfq_rb_root *service_tree = cfqq->service_tree; |
a6d44e98 | 1869 | |
f04a6424 VG |
1870 | BUG_ON(!service_tree); |
1871 | BUG_ON(!service_tree->count); | |
1872 | ||
b6508c16 VG |
1873 | if (!cfqd->cfq_slice_idle) |
1874 | return false; | |
1875 | ||
a6d44e98 CZ |
1876 | /* We never do for idle class queues. */ |
1877 | if (prio == IDLE_WORKLOAD) | |
1878 | return false; | |
1879 | ||
1880 | /* We do for queues that were marked with idle window flag. */ | |
3c764b7a SL |
1881 | if (cfq_cfqq_idle_window(cfqq) && |
1882 | !(blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag)) | |
a6d44e98 CZ |
1883 | return true; |
1884 | ||
1885 | /* | |
1886 | * Otherwise, we do only if they are the last ones | |
1887 | * in their service tree. | |
1888 | */ | |
b1ffe737 | 1889 | if (service_tree->count == 1 && cfq_cfqq_sync(cfqq)) |
c1e44756 | 1890 | return true; |
b1ffe737 DS |
1891 | cfq_log_cfqq(cfqd, cfqq, "Not idling. st->count:%d", |
1892 | service_tree->count); | |
c1e44756 | 1893 | return false; |
a6d44e98 CZ |
1894 | } |
1895 | ||
6d048f53 | 1896 | static void cfq_arm_slice_timer(struct cfq_data *cfqd) |
22e2c507 | 1897 | { |
1792669c | 1898 | struct cfq_queue *cfqq = cfqd->active_queue; |
206dc69b | 1899 | struct cfq_io_context *cic; |
80bdf0c7 | 1900 | unsigned long sl, group_idle = 0; |
7b14e3b5 | 1901 | |
a68bbddb | 1902 | /* |
f7d7b7a7 JA |
1903 | * SSD device without seek penalty, disable idling. But only do so |
1904 | * for devices that support queuing, otherwise we still have a problem | |
1905 | * with sync vs async workloads. | |
a68bbddb | 1906 | */ |
f7d7b7a7 | 1907 | if (blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag) |
a68bbddb JA |
1908 | return; |
1909 | ||
dd67d051 | 1910 | WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list)); |
6d048f53 | 1911 | WARN_ON(cfq_cfqq_slice_new(cfqq)); |
22e2c507 JA |
1912 | |
1913 | /* | |
1914 | * idle is disabled, either manually or by past process history | |
1915 | */ | |
80bdf0c7 VG |
1916 | if (!cfq_should_idle(cfqd, cfqq)) { |
1917 | /* no queue idling. Check for group idling */ | |
1918 | if (cfqd->cfq_group_idle) | |
1919 | group_idle = cfqd->cfq_group_idle; | |
1920 | else | |
1921 | return; | |
1922 | } | |
6d048f53 | 1923 | |
7b679138 | 1924 | /* |
8e550632 | 1925 | * still active requests from this queue, don't idle |
7b679138 | 1926 | */ |
8e550632 | 1927 | if (cfqq->dispatched) |
7b679138 JA |
1928 | return; |
1929 | ||
22e2c507 JA |
1930 | /* |
1931 | * task has exited, don't wait | |
1932 | */ | |
206dc69b | 1933 | cic = cfqd->active_cic; |
66dac98e | 1934 | if (!cic || !atomic_read(&cic->ioc->nr_tasks)) |
6d048f53 JA |
1935 | return; |
1936 | ||
355b659c CZ |
1937 | /* |
1938 | * If our average think time is larger than the remaining time | |
1939 | * slice, then don't idle. This avoids overrunning the allotted | |
1940 | * time slice. | |
1941 | */ | |
1942 | if (sample_valid(cic->ttime_samples) && | |
b1ffe737 DS |
1943 | (cfqq->slice_end - jiffies < cic->ttime_mean)) { |
1944 | cfq_log_cfqq(cfqd, cfqq, "Not idling. think_time:%d", | |
1945 | cic->ttime_mean); | |
355b659c | 1946 | return; |
b1ffe737 | 1947 | } |
355b659c | 1948 | |
80bdf0c7 VG |
1949 | /* There are other queues in the group, don't do group idle */ |
1950 | if (group_idle && cfqq->cfqg->nr_cfqq > 1) | |
1951 | return; | |
1952 | ||
3b18152c | 1953 | cfq_mark_cfqq_wait_request(cfqq); |
22e2c507 | 1954 | |
80bdf0c7 VG |
1955 | if (group_idle) |
1956 | sl = cfqd->cfq_group_idle; | |
1957 | else | |
1958 | sl = cfqd->cfq_slice_idle; | |
206dc69b | 1959 | |
7b14e3b5 | 1960 | mod_timer(&cfqd->idle_slice_timer, jiffies + sl); |
e98ef89b | 1961 | cfq_blkiocg_update_set_idle_time_stats(&cfqq->cfqg->blkg); |
80bdf0c7 VG |
1962 | cfq_log_cfqq(cfqd, cfqq, "arm_idle: %lu group_idle: %d", sl, |
1963 | group_idle ? 1 : 0); | |
1da177e4 LT |
1964 | } |
1965 | ||
498d3aa2 JA |
1966 | /* |
1967 | * Move request from internal lists to the request queue dispatch list. | |
1968 | */ | |
165125e1 | 1969 | static void cfq_dispatch_insert(struct request_queue *q, struct request *rq) |
1da177e4 | 1970 | { |
3ed9a296 | 1971 | struct cfq_data *cfqd = q->elevator->elevator_data; |
5e705374 | 1972 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 | 1973 | |
7b679138 JA |
1974 | cfq_log_cfqq(cfqd, cfqq, "dispatch_insert"); |
1975 | ||
06d21886 | 1976 | cfqq->next_rq = cfq_find_next_rq(cfqd, cfqq, rq); |
5380a101 | 1977 | cfq_remove_request(rq); |
6d048f53 | 1978 | cfqq->dispatched++; |
80bdf0c7 | 1979 | (RQ_CFQG(rq))->dispatched++; |
5380a101 | 1980 | elv_dispatch_sort(q, rq); |
3ed9a296 | 1981 | |
53c583d2 | 1982 | cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]++; |
c4e7893e | 1983 | cfqq->nr_sectors += blk_rq_sectors(rq); |
e98ef89b | 1984 | cfq_blkiocg_update_dispatch_stats(&cfqq->cfqg->blkg, blk_rq_bytes(rq), |
84c124da | 1985 | rq_data_dir(rq), rq_is_sync(rq)); |
1da177e4 LT |
1986 | } |
1987 | ||
1988 | /* | |
1989 | * return expired entry, or NULL to just start from scratch in rbtree | |
1990 | */ | |
febffd61 | 1991 | static struct request *cfq_check_fifo(struct cfq_queue *cfqq) |
1da177e4 | 1992 | { |
30996f40 | 1993 | struct request *rq = NULL; |
1da177e4 | 1994 | |
3b18152c | 1995 | if (cfq_cfqq_fifo_expire(cfqq)) |
1da177e4 | 1996 | return NULL; |
cb887411 JA |
1997 | |
1998 | cfq_mark_cfqq_fifo_expire(cfqq); | |
1999 | ||
89850f7e JA |
2000 | if (list_empty(&cfqq->fifo)) |
2001 | return NULL; | |
1da177e4 | 2002 | |
89850f7e | 2003 | rq = rq_entry_fifo(cfqq->fifo.next); |
30996f40 | 2004 | if (time_before(jiffies, rq_fifo_time(rq))) |
7b679138 | 2005 | rq = NULL; |
1da177e4 | 2006 | |
30996f40 | 2007 | cfq_log_cfqq(cfqq->cfqd, cfqq, "fifo=%p", rq); |
6d048f53 | 2008 | return rq; |
1da177e4 LT |
2009 | } |
2010 | ||
22e2c507 JA |
2011 | static inline int |
2012 | cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
2013 | { | |
2014 | const int base_rq = cfqd->cfq_slice_async_rq; | |
1da177e4 | 2015 | |
22e2c507 | 2016 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); |
1da177e4 | 2017 | |
22e2c507 | 2018 | return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio)); |
1da177e4 LT |
2019 | } |
2020 | ||
df5fe3e8 JM |
2021 | /* |
2022 | * Must be called with the queue_lock held. | |
2023 | */ | |
2024 | static int cfqq_process_refs(struct cfq_queue *cfqq) | |
2025 | { | |
2026 | int process_refs, io_refs; | |
2027 | ||
2028 | io_refs = cfqq->allocated[READ] + cfqq->allocated[WRITE]; | |
30d7b944 | 2029 | process_refs = cfqq->ref - io_refs; |
df5fe3e8 JM |
2030 | BUG_ON(process_refs < 0); |
2031 | return process_refs; | |
2032 | } | |
2033 | ||
2034 | static void cfq_setup_merge(struct cfq_queue *cfqq, struct cfq_queue *new_cfqq) | |
2035 | { | |
e6c5bc73 | 2036 | int process_refs, new_process_refs; |
df5fe3e8 JM |
2037 | struct cfq_queue *__cfqq; |
2038 | ||
c10b61f0 JM |
2039 | /* |
2040 | * If there are no process references on the new_cfqq, then it is | |
2041 | * unsafe to follow the ->new_cfqq chain as other cfqq's in the | |
2042 | * chain may have dropped their last reference (not just their | |
2043 | * last process reference). | |
2044 | */ | |
2045 | if (!cfqq_process_refs(new_cfqq)) | |
2046 | return; | |
2047 | ||
df5fe3e8 JM |
2048 | /* Avoid a circular list and skip interim queue merges */ |
2049 | while ((__cfqq = new_cfqq->new_cfqq)) { | |
2050 | if (__cfqq == cfqq) | |
2051 | return; | |
2052 | new_cfqq = __cfqq; | |
2053 | } | |
2054 | ||
2055 | process_refs = cfqq_process_refs(cfqq); | |
c10b61f0 | 2056 | new_process_refs = cfqq_process_refs(new_cfqq); |
df5fe3e8 JM |
2057 | /* |
2058 | * If the process for the cfqq has gone away, there is no | |
2059 | * sense in merging the queues. | |
2060 | */ | |
c10b61f0 | 2061 | if (process_refs == 0 || new_process_refs == 0) |
df5fe3e8 JM |
2062 | return; |
2063 | ||
e6c5bc73 JM |
2064 | /* |
2065 | * Merge in the direction of the lesser amount of work. | |
2066 | */ | |
e6c5bc73 JM |
2067 | if (new_process_refs >= process_refs) { |
2068 | cfqq->new_cfqq = new_cfqq; | |
30d7b944 | 2069 | new_cfqq->ref += process_refs; |
e6c5bc73 JM |
2070 | } else { |
2071 | new_cfqq->new_cfqq = cfqq; | |
30d7b944 | 2072 | cfqq->ref += new_process_refs; |
e6c5bc73 | 2073 | } |
df5fe3e8 JM |
2074 | } |
2075 | ||
cdb16e8f | 2076 | static enum wl_type_t cfq_choose_wl(struct cfq_data *cfqd, |
65b32a57 | 2077 | struct cfq_group *cfqg, enum wl_prio_t prio) |
718eee05 CZ |
2078 | { |
2079 | struct cfq_queue *queue; | |
2080 | int i; | |
2081 | bool key_valid = false; | |
2082 | unsigned long lowest_key = 0; | |
2083 | enum wl_type_t cur_best = SYNC_NOIDLE_WORKLOAD; | |
2084 | ||
65b32a57 VG |
2085 | for (i = 0; i <= SYNC_WORKLOAD; ++i) { |
2086 | /* select the one with lowest rb_key */ | |
2087 | queue = cfq_rb_first(service_tree_for(cfqg, prio, i)); | |
718eee05 CZ |
2088 | if (queue && |
2089 | (!key_valid || time_before(queue->rb_key, lowest_key))) { | |
2090 | lowest_key = queue->rb_key; | |
2091 | cur_best = i; | |
2092 | key_valid = true; | |
2093 | } | |
2094 | } | |
2095 | ||
2096 | return cur_best; | |
2097 | } | |
2098 | ||
cdb16e8f | 2099 | static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg) |
718eee05 | 2100 | { |
718eee05 CZ |
2101 | unsigned slice; |
2102 | unsigned count; | |
cdb16e8f | 2103 | struct cfq_rb_root *st; |
58ff82f3 | 2104 | unsigned group_slice; |
e4ea0c16 | 2105 | enum wl_prio_t original_prio = cfqd->serving_prio; |
1fa8f6d6 | 2106 | |
718eee05 | 2107 | /* Choose next priority. RT > BE > IDLE */ |
58ff82f3 | 2108 | if (cfq_group_busy_queues_wl(RT_WORKLOAD, cfqd, cfqg)) |
718eee05 | 2109 | cfqd->serving_prio = RT_WORKLOAD; |
58ff82f3 | 2110 | else if (cfq_group_busy_queues_wl(BE_WORKLOAD, cfqd, cfqg)) |
718eee05 CZ |
2111 | cfqd->serving_prio = BE_WORKLOAD; |
2112 | else { | |
2113 | cfqd->serving_prio = IDLE_WORKLOAD; | |
2114 | cfqd->workload_expires = jiffies + 1; | |
2115 | return; | |
2116 | } | |
2117 | ||
e4ea0c16 SL |
2118 | if (original_prio != cfqd->serving_prio) |
2119 | goto new_workload; | |
2120 | ||
718eee05 CZ |
2121 | /* |
2122 | * For RT and BE, we have to choose also the type | |
2123 | * (SYNC, SYNC_NOIDLE, ASYNC), and to compute a workload | |
2124 | * expiration time | |
2125 | */ | |
65b32a57 | 2126 | st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type); |
cdb16e8f | 2127 | count = st->count; |
718eee05 CZ |
2128 | |
2129 | /* | |
65b32a57 | 2130 | * check workload expiration, and that we still have other queues ready |
718eee05 | 2131 | */ |
65b32a57 | 2132 | if (count && !time_after(jiffies, cfqd->workload_expires)) |
718eee05 CZ |
2133 | return; |
2134 | ||
e4ea0c16 | 2135 | new_workload: |
718eee05 CZ |
2136 | /* otherwise select new workload type */ |
2137 | cfqd->serving_type = | |
65b32a57 VG |
2138 | cfq_choose_wl(cfqd, cfqg, cfqd->serving_prio); |
2139 | st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type); | |
cdb16e8f | 2140 | count = st->count; |
718eee05 CZ |
2141 | |
2142 | /* | |
2143 | * the workload slice is computed as a fraction of target latency | |
2144 | * proportional to the number of queues in that workload, over | |
2145 | * all the queues in the same priority class | |
2146 | */ | |
58ff82f3 VG |
2147 | group_slice = cfq_group_slice(cfqd, cfqg); |
2148 | ||
2149 | slice = group_slice * count / | |
2150 | max_t(unsigned, cfqg->busy_queues_avg[cfqd->serving_prio], | |
2151 | cfq_group_busy_queues_wl(cfqd->serving_prio, cfqd, cfqg)); | |
718eee05 | 2152 | |
f26bd1f0 VG |
2153 | if (cfqd->serving_type == ASYNC_WORKLOAD) { |
2154 | unsigned int tmp; | |
2155 | ||
2156 | /* | |
2157 | * Async queues are currently system wide. Just taking | |
2158 | * proportion of queues with-in same group will lead to higher | |
2159 | * async ratio system wide as generally root group is going | |
2160 | * to have higher weight. A more accurate thing would be to | |
2161 | * calculate system wide asnc/sync ratio. | |
2162 | */ | |
2163 | tmp = cfq_target_latency * cfqg_busy_async_queues(cfqd, cfqg); | |
2164 | tmp = tmp/cfqd->busy_queues; | |
2165 | slice = min_t(unsigned, slice, tmp); | |
2166 | ||
718eee05 CZ |
2167 | /* async workload slice is scaled down according to |
2168 | * the sync/async slice ratio. */ | |
2169 | slice = slice * cfqd->cfq_slice[0] / cfqd->cfq_slice[1]; | |
f26bd1f0 | 2170 | } else |
718eee05 CZ |
2171 | /* sync workload slice is at least 2 * cfq_slice_idle */ |
2172 | slice = max(slice, 2 * cfqd->cfq_slice_idle); | |
2173 | ||
2174 | slice = max_t(unsigned, slice, CFQ_MIN_TT); | |
b1ffe737 | 2175 | cfq_log(cfqd, "workload slice:%d", slice); |
718eee05 CZ |
2176 | cfqd->workload_expires = jiffies + slice; |
2177 | } | |
2178 | ||
1fa8f6d6 VG |
2179 | static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd) |
2180 | { | |
2181 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
25bc6b07 | 2182 | struct cfq_group *cfqg; |
1fa8f6d6 VG |
2183 | |
2184 | if (RB_EMPTY_ROOT(&st->rb)) | |
2185 | return NULL; | |
25bc6b07 | 2186 | cfqg = cfq_rb_first_group(st); |
25bc6b07 VG |
2187 | update_min_vdisktime(st); |
2188 | return cfqg; | |
1fa8f6d6 VG |
2189 | } |
2190 | ||
cdb16e8f VG |
2191 | static void cfq_choose_cfqg(struct cfq_data *cfqd) |
2192 | { | |
1fa8f6d6 VG |
2193 | struct cfq_group *cfqg = cfq_get_next_cfqg(cfqd); |
2194 | ||
2195 | cfqd->serving_group = cfqg; | |
dae739eb VG |
2196 | |
2197 | /* Restore the workload type data */ | |
2198 | if (cfqg->saved_workload_slice) { | |
2199 | cfqd->workload_expires = jiffies + cfqg->saved_workload_slice; | |
2200 | cfqd->serving_type = cfqg->saved_workload; | |
2201 | cfqd->serving_prio = cfqg->saved_serving_prio; | |
66ae2919 GJ |
2202 | } else |
2203 | cfqd->workload_expires = jiffies - 1; | |
2204 | ||
1fa8f6d6 | 2205 | choose_service_tree(cfqd, cfqg); |
cdb16e8f VG |
2206 | } |
2207 | ||
22e2c507 | 2208 | /* |
498d3aa2 JA |
2209 | * Select a queue for service. If we have a current active queue, |
2210 | * check whether to continue servicing it, or retrieve and set a new one. | |
22e2c507 | 2211 | */ |
1b5ed5e1 | 2212 | static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) |
1da177e4 | 2213 | { |
a36e71f9 | 2214 | struct cfq_queue *cfqq, *new_cfqq = NULL; |
1da177e4 | 2215 | |
22e2c507 JA |
2216 | cfqq = cfqd->active_queue; |
2217 | if (!cfqq) | |
2218 | goto new_queue; | |
1da177e4 | 2219 | |
f04a6424 VG |
2220 | if (!cfqd->rq_queued) |
2221 | return NULL; | |
c244bb50 VG |
2222 | |
2223 | /* | |
2224 | * We were waiting for group to get backlogged. Expire the queue | |
2225 | */ | |
2226 | if (cfq_cfqq_wait_busy(cfqq) && !RB_EMPTY_ROOT(&cfqq->sort_list)) | |
2227 | goto expire; | |
2228 | ||
22e2c507 | 2229 | /* |
6d048f53 | 2230 | * The active queue has run out of time, expire it and select new. |
22e2c507 | 2231 | */ |
7667aa06 VG |
2232 | if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq)) { |
2233 | /* | |
2234 | * If slice had not expired at the completion of last request | |
2235 | * we might not have turned on wait_busy flag. Don't expire | |
2236 | * the queue yet. Allow the group to get backlogged. | |
2237 | * | |
2238 | * The very fact that we have used the slice, that means we | |
2239 | * have been idling all along on this queue and it should be | |
2240 | * ok to wait for this request to complete. | |
2241 | */ | |
82bbbf28 VG |
2242 | if (cfqq->cfqg->nr_cfqq == 1 && RB_EMPTY_ROOT(&cfqq->sort_list) |
2243 | && cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) { | |
2244 | cfqq = NULL; | |
7667aa06 | 2245 | goto keep_queue; |
82bbbf28 | 2246 | } else |
80bdf0c7 | 2247 | goto check_group_idle; |
7667aa06 | 2248 | } |
1da177e4 | 2249 | |
22e2c507 | 2250 | /* |
6d048f53 JA |
2251 | * The active queue has requests and isn't expired, allow it to |
2252 | * dispatch. | |
22e2c507 | 2253 | */ |
dd67d051 | 2254 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
22e2c507 | 2255 | goto keep_queue; |
6d048f53 | 2256 | |
a36e71f9 JA |
2257 | /* |
2258 | * If another queue has a request waiting within our mean seek | |
2259 | * distance, let it run. The expire code will check for close | |
2260 | * cooperators and put the close queue at the front of the service | |
df5fe3e8 | 2261 | * tree. If possible, merge the expiring queue with the new cfqq. |
a36e71f9 | 2262 | */ |
b3b6d040 | 2263 | new_cfqq = cfq_close_cooperator(cfqd, cfqq); |
df5fe3e8 JM |
2264 | if (new_cfqq) { |
2265 | if (!cfqq->new_cfqq) | |
2266 | cfq_setup_merge(cfqq, new_cfqq); | |
a36e71f9 | 2267 | goto expire; |
df5fe3e8 | 2268 | } |
a36e71f9 | 2269 | |
6d048f53 JA |
2270 | /* |
2271 | * No requests pending. If the active queue still has requests in | |
2272 | * flight or is idling for a new request, allow either of these | |
2273 | * conditions to happen (or time out) before selecting a new queue. | |
2274 | */ | |
80bdf0c7 VG |
2275 | if (timer_pending(&cfqd->idle_slice_timer)) { |
2276 | cfqq = NULL; | |
2277 | goto keep_queue; | |
2278 | } | |
2279 | ||
8e1ac665 SL |
2280 | /* |
2281 | * This is a deep seek queue, but the device is much faster than | |
2282 | * the queue can deliver, don't idle | |
2283 | **/ | |
2284 | if (CFQQ_SEEKY(cfqq) && cfq_cfqq_idle_window(cfqq) && | |
2285 | (cfq_cfqq_slice_new(cfqq) || | |
2286 | (cfqq->slice_end - jiffies > jiffies - cfqq->slice_start))) { | |
2287 | cfq_clear_cfqq_deep(cfqq); | |
2288 | cfq_clear_cfqq_idle_window(cfqq); | |
2289 | } | |
2290 | ||
80bdf0c7 VG |
2291 | if (cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) { |
2292 | cfqq = NULL; | |
2293 | goto keep_queue; | |
2294 | } | |
2295 | ||
2296 | /* | |
2297 | * If group idle is enabled and there are requests dispatched from | |
2298 | * this group, wait for requests to complete. | |
2299 | */ | |
2300 | check_group_idle: | |
2301 | if (cfqd->cfq_group_idle && cfqq->cfqg->nr_cfqq == 1 | |
2302 | && cfqq->cfqg->dispatched) { | |
caaa5f9f JA |
2303 | cfqq = NULL; |
2304 | goto keep_queue; | |
22e2c507 JA |
2305 | } |
2306 | ||
3b18152c | 2307 | expire: |
e5ff082e | 2308 | cfq_slice_expired(cfqd, 0); |
3b18152c | 2309 | new_queue: |
718eee05 CZ |
2310 | /* |
2311 | * Current queue expired. Check if we have to switch to a new | |
2312 | * service tree | |
2313 | */ | |
2314 | if (!new_cfqq) | |
cdb16e8f | 2315 | cfq_choose_cfqg(cfqd); |
718eee05 | 2316 | |
a36e71f9 | 2317 | cfqq = cfq_set_active_queue(cfqd, new_cfqq); |
22e2c507 | 2318 | keep_queue: |
3b18152c | 2319 | return cfqq; |
22e2c507 JA |
2320 | } |
2321 | ||
febffd61 | 2322 | static int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq) |
d9e7620e JA |
2323 | { |
2324 | int dispatched = 0; | |
2325 | ||
2326 | while (cfqq->next_rq) { | |
2327 | cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq); | |
2328 | dispatched++; | |
2329 | } | |
2330 | ||
2331 | BUG_ON(!list_empty(&cfqq->fifo)); | |
f04a6424 VG |
2332 | |
2333 | /* By default cfqq is not expired if it is empty. Do it explicitly */ | |
e5ff082e | 2334 | __cfq_slice_expired(cfqq->cfqd, cfqq, 0); |
d9e7620e JA |
2335 | return dispatched; |
2336 | } | |
2337 | ||
498d3aa2 JA |
2338 | /* |
2339 | * Drain our current requests. Used for barriers and when switching | |
2340 | * io schedulers on-the-fly. | |
2341 | */ | |
d9e7620e | 2342 | static int cfq_forced_dispatch(struct cfq_data *cfqd) |
1b5ed5e1 | 2343 | { |
0871714e | 2344 | struct cfq_queue *cfqq; |
d9e7620e | 2345 | int dispatched = 0; |
cdb16e8f | 2346 | |
3440c49f | 2347 | /* Expire the timeslice of the current active queue first */ |
e5ff082e | 2348 | cfq_slice_expired(cfqd, 0); |
3440c49f DS |
2349 | while ((cfqq = cfq_get_next_queue_forced(cfqd)) != NULL) { |
2350 | __cfq_set_active_queue(cfqd, cfqq); | |
f04a6424 | 2351 | dispatched += __cfq_forced_dispatch_cfqq(cfqq); |
3440c49f | 2352 | } |
1b5ed5e1 | 2353 | |
1b5ed5e1 TH |
2354 | BUG_ON(cfqd->busy_queues); |
2355 | ||
6923715a | 2356 | cfq_log(cfqd, "forced_dispatch=%d", dispatched); |
1b5ed5e1 TH |
2357 | return dispatched; |
2358 | } | |
2359 | ||
abc3c744 SL |
2360 | static inline bool cfq_slice_used_soon(struct cfq_data *cfqd, |
2361 | struct cfq_queue *cfqq) | |
2362 | { | |
2363 | /* the queue hasn't finished any request, can't estimate */ | |
2364 | if (cfq_cfqq_slice_new(cfqq)) | |
c1e44756 | 2365 | return true; |
abc3c744 SL |
2366 | if (time_after(jiffies + cfqd->cfq_slice_idle * cfqq->dispatched, |
2367 | cfqq->slice_end)) | |
c1e44756 | 2368 | return true; |
abc3c744 | 2369 | |
c1e44756 | 2370 | return false; |
abc3c744 SL |
2371 | } |
2372 | ||
0b182d61 | 2373 | static bool cfq_may_dispatch(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
2f5cb738 | 2374 | { |
2f5cb738 | 2375 | unsigned int max_dispatch; |
22e2c507 | 2376 | |
5ad531db JA |
2377 | /* |
2378 | * Drain async requests before we start sync IO | |
2379 | */ | |
53c583d2 | 2380 | if (cfq_should_idle(cfqd, cfqq) && cfqd->rq_in_flight[BLK_RW_ASYNC]) |
0b182d61 | 2381 | return false; |
5ad531db | 2382 | |
2f5cb738 JA |
2383 | /* |
2384 | * If this is an async queue and we have sync IO in flight, let it wait | |
2385 | */ | |
53c583d2 | 2386 | if (cfqd->rq_in_flight[BLK_RW_SYNC] && !cfq_cfqq_sync(cfqq)) |
0b182d61 | 2387 | return false; |
2f5cb738 | 2388 | |
abc3c744 | 2389 | max_dispatch = max_t(unsigned int, cfqd->cfq_quantum / 2, 1); |
2f5cb738 JA |
2390 | if (cfq_class_idle(cfqq)) |
2391 | max_dispatch = 1; | |
b4878f24 | 2392 | |
2f5cb738 JA |
2393 | /* |
2394 | * Does this cfqq already have too much IO in flight? | |
2395 | */ | |
2396 | if (cfqq->dispatched >= max_dispatch) { | |
2397 | /* | |
2398 | * idle queue must always only have a single IO in flight | |
2399 | */ | |
3ed9a296 | 2400 | if (cfq_class_idle(cfqq)) |
0b182d61 | 2401 | return false; |
3ed9a296 | 2402 | |
2f5cb738 JA |
2403 | /* |
2404 | * We have other queues, don't allow more IO from this one | |
2405 | */ | |
abc3c744 | 2406 | if (cfqd->busy_queues > 1 && cfq_slice_used_soon(cfqd, cfqq)) |
0b182d61 | 2407 | return false; |
9ede209e | 2408 | |
365722bb | 2409 | /* |
474b18cc | 2410 | * Sole queue user, no limit |
365722bb | 2411 | */ |
abc3c744 SL |
2412 | if (cfqd->busy_queues == 1) |
2413 | max_dispatch = -1; | |
2414 | else | |
2415 | /* | |
2416 | * Normally we start throttling cfqq when cfq_quantum/2 | |
2417 | * requests have been dispatched. But we can drive | |
2418 | * deeper queue depths at the beginning of slice | |
2419 | * subjected to upper limit of cfq_quantum. | |
2420 | * */ | |
2421 | max_dispatch = cfqd->cfq_quantum; | |
8e296755 JA |
2422 | } |
2423 | ||
2424 | /* | |
2425 | * Async queues must wait a bit before being allowed dispatch. | |
2426 | * We also ramp up the dispatch depth gradually for async IO, | |
2427 | * based on the last sync IO we serviced | |
2428 | */ | |
963b72fc | 2429 | if (!cfq_cfqq_sync(cfqq) && cfqd->cfq_latency) { |
573412b2 | 2430 | unsigned long last_sync = jiffies - cfqd->last_delayed_sync; |
8e296755 | 2431 | unsigned int depth; |
365722bb | 2432 | |
61f0c1dc | 2433 | depth = last_sync / cfqd->cfq_slice[1]; |
e00c54c3 JA |
2434 | if (!depth && !cfqq->dispatched) |
2435 | depth = 1; | |
8e296755 JA |
2436 | if (depth < max_dispatch) |
2437 | max_dispatch = depth; | |
2f5cb738 | 2438 | } |
3ed9a296 | 2439 | |
0b182d61 JA |
2440 | /* |
2441 | * If we're below the current max, allow a dispatch | |
2442 | */ | |
2443 | return cfqq->dispatched < max_dispatch; | |
2444 | } | |
2445 | ||
2446 | /* | |
2447 | * Dispatch a request from cfqq, moving them to the request queue | |
2448 | * dispatch list. | |
2449 | */ | |
2450 | static bool cfq_dispatch_request(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
2451 | { | |
2452 | struct request *rq; | |
2453 | ||
2454 | BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list)); | |
2455 | ||
2456 | if (!cfq_may_dispatch(cfqd, cfqq)) | |
2457 | return false; | |
2458 | ||
2459 | /* | |
2460 | * follow expired path, else get first next available | |
2461 | */ | |
2462 | rq = cfq_check_fifo(cfqq); | |
2463 | if (!rq) | |
2464 | rq = cfqq->next_rq; | |
2465 | ||
2466 | /* | |
2467 | * insert request into driver dispatch list | |
2468 | */ | |
2469 | cfq_dispatch_insert(cfqd->queue, rq); | |
2470 | ||
2471 | if (!cfqd->active_cic) { | |
2472 | struct cfq_io_context *cic = RQ_CIC(rq); | |
2473 | ||
2474 | atomic_long_inc(&cic->ioc->refcount); | |
2475 | cfqd->active_cic = cic; | |
2476 | } | |
2477 | ||
2478 | return true; | |
2479 | } | |
2480 | ||
2481 | /* | |
2482 | * Find the cfqq that we need to service and move a request from that to the | |
2483 | * dispatch list | |
2484 | */ | |
2485 | static int cfq_dispatch_requests(struct request_queue *q, int force) | |
2486 | { | |
2487 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
2488 | struct cfq_queue *cfqq; | |
2489 | ||
2490 | if (!cfqd->busy_queues) | |
2491 | return 0; | |
2492 | ||
2493 | if (unlikely(force)) | |
2494 | return cfq_forced_dispatch(cfqd); | |
2495 | ||
2496 | cfqq = cfq_select_queue(cfqd); | |
2497 | if (!cfqq) | |
8e296755 JA |
2498 | return 0; |
2499 | ||
2f5cb738 | 2500 | /* |
0b182d61 | 2501 | * Dispatch a request from this cfqq, if it is allowed |
2f5cb738 | 2502 | */ |
0b182d61 JA |
2503 | if (!cfq_dispatch_request(cfqd, cfqq)) |
2504 | return 0; | |
2505 | ||
2f5cb738 | 2506 | cfqq->slice_dispatch++; |
b029195d | 2507 | cfq_clear_cfqq_must_dispatch(cfqq); |
22e2c507 | 2508 | |
2f5cb738 JA |
2509 | /* |
2510 | * expire an async queue immediately if it has used up its slice. idle | |
2511 | * queue always expire after 1 dispatch round. | |
2512 | */ | |
2513 | if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) && | |
2514 | cfqq->slice_dispatch >= cfq_prio_to_maxrq(cfqd, cfqq)) || | |
2515 | cfq_class_idle(cfqq))) { | |
2516 | cfqq->slice_end = jiffies + 1; | |
e5ff082e | 2517 | cfq_slice_expired(cfqd, 0); |
1da177e4 LT |
2518 | } |
2519 | ||
b217a903 | 2520 | cfq_log_cfqq(cfqd, cfqq, "dispatched a request"); |
2f5cb738 | 2521 | return 1; |
1da177e4 LT |
2522 | } |
2523 | ||
1da177e4 | 2524 | /* |
5e705374 JA |
2525 | * task holds one reference to the queue, dropped when task exits. each rq |
2526 | * in-flight on this queue also holds a reference, dropped when rq is freed. | |
1da177e4 | 2527 | * |
b1c35769 | 2528 | * Each cfq queue took a reference on the parent group. Drop it now. |
1da177e4 LT |
2529 | * queue lock must be held here. |
2530 | */ | |
2531 | static void cfq_put_queue(struct cfq_queue *cfqq) | |
2532 | { | |
22e2c507 | 2533 | struct cfq_data *cfqd = cfqq->cfqd; |
878eaddd | 2534 | struct cfq_group *cfqg, *orig_cfqg; |
22e2c507 | 2535 | |
30d7b944 | 2536 | BUG_ON(cfqq->ref <= 0); |
1da177e4 | 2537 | |
30d7b944 SL |
2538 | cfqq->ref--; |
2539 | if (cfqq->ref) | |
1da177e4 LT |
2540 | return; |
2541 | ||
7b679138 | 2542 | cfq_log_cfqq(cfqd, cfqq, "put_queue"); |
1da177e4 | 2543 | BUG_ON(rb_first(&cfqq->sort_list)); |
22e2c507 | 2544 | BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]); |
b1c35769 | 2545 | cfqg = cfqq->cfqg; |
878eaddd | 2546 | orig_cfqg = cfqq->orig_cfqg; |
1da177e4 | 2547 | |
28f95cbc | 2548 | if (unlikely(cfqd->active_queue == cfqq)) { |
e5ff082e | 2549 | __cfq_slice_expired(cfqd, cfqq, 0); |
23e018a1 | 2550 | cfq_schedule_dispatch(cfqd); |
28f95cbc | 2551 | } |
22e2c507 | 2552 | |
f04a6424 | 2553 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
1da177e4 | 2554 | kmem_cache_free(cfq_pool, cfqq); |
b1c35769 | 2555 | cfq_put_cfqg(cfqg); |
878eaddd VG |
2556 | if (orig_cfqg) |
2557 | cfq_put_cfqg(orig_cfqg); | |
1da177e4 LT |
2558 | } |
2559 | ||
d6de8be7 JA |
2560 | /* |
2561 | * Must always be called with the rcu_read_lock() held | |
2562 | */ | |
07416d29 JA |
2563 | static void |
2564 | __call_for_each_cic(struct io_context *ioc, | |
2565 | void (*func)(struct io_context *, struct cfq_io_context *)) | |
2566 | { | |
2567 | struct cfq_io_context *cic; | |
2568 | struct hlist_node *n; | |
2569 | ||
2570 | hlist_for_each_entry_rcu(cic, n, &ioc->cic_list, cic_list) | |
2571 | func(ioc, cic); | |
2572 | } | |
2573 | ||
4ac845a2 | 2574 | /* |
34e6bbf2 | 2575 | * Call func for each cic attached to this ioc. |
4ac845a2 | 2576 | */ |
34e6bbf2 | 2577 | static void |
4ac845a2 JA |
2578 | call_for_each_cic(struct io_context *ioc, |
2579 | void (*func)(struct io_context *, struct cfq_io_context *)) | |
1da177e4 | 2580 | { |
4ac845a2 | 2581 | rcu_read_lock(); |
07416d29 | 2582 | __call_for_each_cic(ioc, func); |
4ac845a2 | 2583 | rcu_read_unlock(); |
34e6bbf2 FC |
2584 | } |
2585 | ||
2586 | static void cfq_cic_free_rcu(struct rcu_head *head) | |
2587 | { | |
2588 | struct cfq_io_context *cic; | |
2589 | ||
2590 | cic = container_of(head, struct cfq_io_context, rcu_head); | |
2591 | ||
2592 | kmem_cache_free(cfq_ioc_pool, cic); | |
245b2e70 | 2593 | elv_ioc_count_dec(cfq_ioc_count); |
34e6bbf2 | 2594 | |
9a11b4ed JA |
2595 | if (ioc_gone) { |
2596 | /* | |
2597 | * CFQ scheduler is exiting, grab exit lock and check | |
2598 | * the pending io context count. If it hits zero, | |
2599 | * complete ioc_gone and set it back to NULL | |
2600 | */ | |
2601 | spin_lock(&ioc_gone_lock); | |
245b2e70 | 2602 | if (ioc_gone && !elv_ioc_count_read(cfq_ioc_count)) { |
9a11b4ed JA |
2603 | complete(ioc_gone); |
2604 | ioc_gone = NULL; | |
2605 | } | |
2606 | spin_unlock(&ioc_gone_lock); | |
2607 | } | |
34e6bbf2 | 2608 | } |
4ac845a2 | 2609 | |
34e6bbf2 FC |
2610 | static void cfq_cic_free(struct cfq_io_context *cic) |
2611 | { | |
2612 | call_rcu(&cic->rcu_head, cfq_cic_free_rcu); | |
4ac845a2 JA |
2613 | } |
2614 | ||
2615 | static void cic_free_func(struct io_context *ioc, struct cfq_io_context *cic) | |
2616 | { | |
2617 | unsigned long flags; | |
bca4b914 | 2618 | unsigned long dead_key = (unsigned long) cic->key; |
4ac845a2 | 2619 | |
bca4b914 | 2620 | BUG_ON(!(dead_key & CIC_DEAD_KEY)); |
4ac845a2 JA |
2621 | |
2622 | spin_lock_irqsave(&ioc->lock, flags); | |
80b15c73 | 2623 | radix_tree_delete(&ioc->radix_root, dead_key >> CIC_DEAD_INDEX_SHIFT); |
ffc4e759 | 2624 | hlist_del_rcu(&cic->cic_list); |
4ac845a2 JA |
2625 | spin_unlock_irqrestore(&ioc->lock, flags); |
2626 | ||
34e6bbf2 | 2627 | cfq_cic_free(cic); |
4ac845a2 JA |
2628 | } |
2629 | ||
d6de8be7 JA |
2630 | /* |
2631 | * Must be called with rcu_read_lock() held or preemption otherwise disabled. | |
2632 | * Only two callers of this - ->dtor() which is called with the rcu_read_lock(), | |
2633 | * and ->trim() which is called with the task lock held | |
2634 | */ | |
4ac845a2 JA |
2635 | static void cfq_free_io_context(struct io_context *ioc) |
2636 | { | |
4ac845a2 | 2637 | /* |
34e6bbf2 FC |
2638 | * ioc->refcount is zero here, or we are called from elv_unregister(), |
2639 | * so no more cic's are allowed to be linked into this ioc. So it | |
2640 | * should be ok to iterate over the known list, we will see all cic's | |
2641 | * since no new ones are added. | |
4ac845a2 | 2642 | */ |
07416d29 | 2643 | __call_for_each_cic(ioc, cic_free_func); |
1da177e4 LT |
2644 | } |
2645 | ||
d02a2c07 | 2646 | static void cfq_put_cooperator(struct cfq_queue *cfqq) |
1da177e4 | 2647 | { |
df5fe3e8 JM |
2648 | struct cfq_queue *__cfqq, *next; |
2649 | ||
df5fe3e8 JM |
2650 | /* |
2651 | * If this queue was scheduled to merge with another queue, be | |
2652 | * sure to drop the reference taken on that queue (and others in | |
2653 | * the merge chain). See cfq_setup_merge and cfq_merge_cfqqs. | |
2654 | */ | |
2655 | __cfqq = cfqq->new_cfqq; | |
2656 | while (__cfqq) { | |
2657 | if (__cfqq == cfqq) { | |
2658 | WARN(1, "cfqq->new_cfqq loop detected\n"); | |
2659 | break; | |
2660 | } | |
2661 | next = __cfqq->new_cfqq; | |
2662 | cfq_put_queue(__cfqq); | |
2663 | __cfqq = next; | |
2664 | } | |
d02a2c07 SL |
2665 | } |
2666 | ||
2667 | static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
2668 | { | |
2669 | if (unlikely(cfqq == cfqd->active_queue)) { | |
2670 | __cfq_slice_expired(cfqd, cfqq, 0); | |
2671 | cfq_schedule_dispatch(cfqd); | |
2672 | } | |
2673 | ||
2674 | cfq_put_cooperator(cfqq); | |
df5fe3e8 | 2675 | |
89850f7e JA |
2676 | cfq_put_queue(cfqq); |
2677 | } | |
22e2c507 | 2678 | |
89850f7e JA |
2679 | static void __cfq_exit_single_io_context(struct cfq_data *cfqd, |
2680 | struct cfq_io_context *cic) | |
2681 | { | |
4faa3c81 FC |
2682 | struct io_context *ioc = cic->ioc; |
2683 | ||
fc46379d | 2684 | list_del_init(&cic->queue_list); |
4ac845a2 JA |
2685 | |
2686 | /* | |
bca4b914 | 2687 | * Make sure dead mark is seen for dead queues |
4ac845a2 | 2688 | */ |
fc46379d | 2689 | smp_wmb(); |
bca4b914 | 2690 | cic->key = cfqd_dead_key(cfqd); |
fc46379d | 2691 | |
4faa3c81 FC |
2692 | if (ioc->ioc_data == cic) |
2693 | rcu_assign_pointer(ioc->ioc_data, NULL); | |
2694 | ||
ff6657c6 JA |
2695 | if (cic->cfqq[BLK_RW_ASYNC]) { |
2696 | cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_ASYNC]); | |
2697 | cic->cfqq[BLK_RW_ASYNC] = NULL; | |
12a05732 AV |
2698 | } |
2699 | ||
ff6657c6 JA |
2700 | if (cic->cfqq[BLK_RW_SYNC]) { |
2701 | cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_SYNC]); | |
2702 | cic->cfqq[BLK_RW_SYNC] = NULL; | |
12a05732 | 2703 | } |
89850f7e JA |
2704 | } |
2705 | ||
4ac845a2 JA |
2706 | static void cfq_exit_single_io_context(struct io_context *ioc, |
2707 | struct cfq_io_context *cic) | |
89850f7e | 2708 | { |
bca4b914 | 2709 | struct cfq_data *cfqd = cic_to_cfqd(cic); |
89850f7e | 2710 | |
89850f7e | 2711 | if (cfqd) { |
165125e1 | 2712 | struct request_queue *q = cfqd->queue; |
4ac845a2 | 2713 | unsigned long flags; |
89850f7e | 2714 | |
4ac845a2 | 2715 | spin_lock_irqsave(q->queue_lock, flags); |
62c1fe9d JA |
2716 | |
2717 | /* | |
2718 | * Ensure we get a fresh copy of the ->key to prevent | |
2719 | * race between exiting task and queue | |
2720 | */ | |
2721 | smp_read_barrier_depends(); | |
bca4b914 | 2722 | if (cic->key == cfqd) |
62c1fe9d JA |
2723 | __cfq_exit_single_io_context(cfqd, cic); |
2724 | ||
4ac845a2 | 2725 | spin_unlock_irqrestore(q->queue_lock, flags); |
89850f7e | 2726 | } |
1da177e4 LT |
2727 | } |
2728 | ||
498d3aa2 JA |
2729 | /* |
2730 | * The process that ioc belongs to has exited, we need to clean up | |
2731 | * and put the internal structures we have that belongs to that process. | |
2732 | */ | |
e2d74ac0 | 2733 | static void cfq_exit_io_context(struct io_context *ioc) |
1da177e4 | 2734 | { |
4ac845a2 | 2735 | call_for_each_cic(ioc, cfq_exit_single_io_context); |
1da177e4 LT |
2736 | } |
2737 | ||
22e2c507 | 2738 | static struct cfq_io_context * |
8267e268 | 2739 | cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
1da177e4 | 2740 | { |
b5deef90 | 2741 | struct cfq_io_context *cic; |
1da177e4 | 2742 | |
94f6030c CL |
2743 | cic = kmem_cache_alloc_node(cfq_ioc_pool, gfp_mask | __GFP_ZERO, |
2744 | cfqd->queue->node); | |
1da177e4 | 2745 | if (cic) { |
22e2c507 | 2746 | cic->last_end_request = jiffies; |
553698f9 | 2747 | INIT_LIST_HEAD(&cic->queue_list); |
ffc4e759 | 2748 | INIT_HLIST_NODE(&cic->cic_list); |
22e2c507 JA |
2749 | cic->dtor = cfq_free_io_context; |
2750 | cic->exit = cfq_exit_io_context; | |
245b2e70 | 2751 | elv_ioc_count_inc(cfq_ioc_count); |
1da177e4 LT |
2752 | } |
2753 | ||
2754 | return cic; | |
2755 | } | |
2756 | ||
fd0928df | 2757 | static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc) |
22e2c507 JA |
2758 | { |
2759 | struct task_struct *tsk = current; | |
2760 | int ioprio_class; | |
2761 | ||
3b18152c | 2762 | if (!cfq_cfqq_prio_changed(cfqq)) |
22e2c507 JA |
2763 | return; |
2764 | ||
fd0928df | 2765 | ioprio_class = IOPRIO_PRIO_CLASS(ioc->ioprio); |
22e2c507 | 2766 | switch (ioprio_class) { |
fe094d98 JA |
2767 | default: |
2768 | printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class); | |
2769 | case IOPRIO_CLASS_NONE: | |
2770 | /* | |
6d63c275 | 2771 | * no prio set, inherit CPU scheduling settings |
fe094d98 JA |
2772 | */ |
2773 | cfqq->ioprio = task_nice_ioprio(tsk); | |
6d63c275 | 2774 | cfqq->ioprio_class = task_nice_ioclass(tsk); |
fe094d98 JA |
2775 | break; |
2776 | case IOPRIO_CLASS_RT: | |
2777 | cfqq->ioprio = task_ioprio(ioc); | |
2778 | cfqq->ioprio_class = IOPRIO_CLASS_RT; | |
2779 | break; | |
2780 | case IOPRIO_CLASS_BE: | |
2781 | cfqq->ioprio = task_ioprio(ioc); | |
2782 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
2783 | break; | |
2784 | case IOPRIO_CLASS_IDLE: | |
2785 | cfqq->ioprio_class = IOPRIO_CLASS_IDLE; | |
2786 | cfqq->ioprio = 7; | |
2787 | cfq_clear_cfqq_idle_window(cfqq); | |
2788 | break; | |
22e2c507 JA |
2789 | } |
2790 | ||
2791 | /* | |
2792 | * keep track of original prio settings in case we have to temporarily | |
2793 | * elevate the priority of this queue | |
2794 | */ | |
2795 | cfqq->org_ioprio = cfqq->ioprio; | |
2796 | cfqq->org_ioprio_class = cfqq->ioprio_class; | |
3b18152c | 2797 | cfq_clear_cfqq_prio_changed(cfqq); |
22e2c507 JA |
2798 | } |
2799 | ||
febffd61 | 2800 | static void changed_ioprio(struct io_context *ioc, struct cfq_io_context *cic) |
22e2c507 | 2801 | { |
bca4b914 | 2802 | struct cfq_data *cfqd = cic_to_cfqd(cic); |
478a82b0 | 2803 | struct cfq_queue *cfqq; |
c1b707d2 | 2804 | unsigned long flags; |
35e6077c | 2805 | |
caaa5f9f JA |
2806 | if (unlikely(!cfqd)) |
2807 | return; | |
2808 | ||
c1b707d2 | 2809 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); |
caaa5f9f | 2810 | |
ff6657c6 | 2811 | cfqq = cic->cfqq[BLK_RW_ASYNC]; |
caaa5f9f JA |
2812 | if (cfqq) { |
2813 | struct cfq_queue *new_cfqq; | |
ff6657c6 JA |
2814 | new_cfqq = cfq_get_queue(cfqd, BLK_RW_ASYNC, cic->ioc, |
2815 | GFP_ATOMIC); | |
caaa5f9f | 2816 | if (new_cfqq) { |
ff6657c6 | 2817 | cic->cfqq[BLK_RW_ASYNC] = new_cfqq; |
caaa5f9f JA |
2818 | cfq_put_queue(cfqq); |
2819 | } | |
22e2c507 | 2820 | } |
caaa5f9f | 2821 | |
ff6657c6 | 2822 | cfqq = cic->cfqq[BLK_RW_SYNC]; |
caaa5f9f JA |
2823 | if (cfqq) |
2824 | cfq_mark_cfqq_prio_changed(cfqq); | |
2825 | ||
c1b707d2 | 2826 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); |
22e2c507 JA |
2827 | } |
2828 | ||
fc46379d | 2829 | static void cfq_ioc_set_ioprio(struct io_context *ioc) |
22e2c507 | 2830 | { |
4ac845a2 | 2831 | call_for_each_cic(ioc, changed_ioprio); |
fc46379d | 2832 | ioc->ioprio_changed = 0; |
22e2c507 JA |
2833 | } |
2834 | ||
d5036d77 | 2835 | static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
a6151c3a | 2836 | pid_t pid, bool is_sync) |
d5036d77 JA |
2837 | { |
2838 | RB_CLEAR_NODE(&cfqq->rb_node); | |
2839 | RB_CLEAR_NODE(&cfqq->p_node); | |
2840 | INIT_LIST_HEAD(&cfqq->fifo); | |
2841 | ||
30d7b944 | 2842 | cfqq->ref = 0; |
d5036d77 JA |
2843 | cfqq->cfqd = cfqd; |
2844 | ||
2845 | cfq_mark_cfqq_prio_changed(cfqq); | |
2846 | ||
2847 | if (is_sync) { | |
2848 | if (!cfq_class_idle(cfqq)) | |
2849 | cfq_mark_cfqq_idle_window(cfqq); | |
2850 | cfq_mark_cfqq_sync(cfqq); | |
2851 | } | |
2852 | cfqq->pid = pid; | |
2853 | } | |
2854 | ||
24610333 VG |
2855 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
2856 | static void changed_cgroup(struct io_context *ioc, struct cfq_io_context *cic) | |
2857 | { | |
2858 | struct cfq_queue *sync_cfqq = cic_to_cfqq(cic, 1); | |
bca4b914 | 2859 | struct cfq_data *cfqd = cic_to_cfqd(cic); |
24610333 VG |
2860 | unsigned long flags; |
2861 | struct request_queue *q; | |
2862 | ||
2863 | if (unlikely(!cfqd)) | |
2864 | return; | |
2865 | ||
2866 | q = cfqd->queue; | |
2867 | ||
2868 | spin_lock_irqsave(q->queue_lock, flags); | |
2869 | ||
2870 | if (sync_cfqq) { | |
2871 | /* | |
2872 | * Drop reference to sync queue. A new sync queue will be | |
2873 | * assigned in new group upon arrival of a fresh request. | |
2874 | */ | |
2875 | cfq_log_cfqq(cfqd, sync_cfqq, "changed cgroup"); | |
2876 | cic_set_cfqq(cic, NULL, 1); | |
2877 | cfq_put_queue(sync_cfqq); | |
2878 | } | |
2879 | ||
2880 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2881 | } | |
2882 | ||
2883 | static void cfq_ioc_set_cgroup(struct io_context *ioc) | |
2884 | { | |
2885 | call_for_each_cic(ioc, changed_cgroup); | |
2886 | ioc->cgroup_changed = 0; | |
2887 | } | |
2888 | #endif /* CONFIG_CFQ_GROUP_IOSCHED */ | |
2889 | ||
22e2c507 | 2890 | static struct cfq_queue * |
a6151c3a | 2891 | cfq_find_alloc_queue(struct cfq_data *cfqd, bool is_sync, |
fd0928df | 2892 | struct io_context *ioc, gfp_t gfp_mask) |
22e2c507 | 2893 | { |
22e2c507 | 2894 | struct cfq_queue *cfqq, *new_cfqq = NULL; |
91fac317 | 2895 | struct cfq_io_context *cic; |
cdb16e8f | 2896 | struct cfq_group *cfqg; |
22e2c507 JA |
2897 | |
2898 | retry: | |
cdb16e8f | 2899 | cfqg = cfq_get_cfqg(cfqd, 1); |
4ac845a2 | 2900 | cic = cfq_cic_lookup(cfqd, ioc); |
91fac317 VT |
2901 | /* cic always exists here */ |
2902 | cfqq = cic_to_cfqq(cic, is_sync); | |
22e2c507 | 2903 | |
6118b70b JA |
2904 | /* |
2905 | * Always try a new alloc if we fell back to the OOM cfqq | |
2906 | * originally, since it should just be a temporary situation. | |
2907 | */ | |
2908 | if (!cfqq || cfqq == &cfqd->oom_cfqq) { | |
2909 | cfqq = NULL; | |
22e2c507 JA |
2910 | if (new_cfqq) { |
2911 | cfqq = new_cfqq; | |
2912 | new_cfqq = NULL; | |
2913 | } else if (gfp_mask & __GFP_WAIT) { | |
2914 | spin_unlock_irq(cfqd->queue->queue_lock); | |
94f6030c | 2915 | new_cfqq = kmem_cache_alloc_node(cfq_pool, |
6118b70b | 2916 | gfp_mask | __GFP_ZERO, |
94f6030c | 2917 | cfqd->queue->node); |
22e2c507 | 2918 | spin_lock_irq(cfqd->queue->queue_lock); |
6118b70b JA |
2919 | if (new_cfqq) |
2920 | goto retry; | |
22e2c507 | 2921 | } else { |
94f6030c CL |
2922 | cfqq = kmem_cache_alloc_node(cfq_pool, |
2923 | gfp_mask | __GFP_ZERO, | |
2924 | cfqd->queue->node); | |
22e2c507 JA |
2925 | } |
2926 | ||
6118b70b JA |
2927 | if (cfqq) { |
2928 | cfq_init_cfqq(cfqd, cfqq, current->pid, is_sync); | |
2929 | cfq_init_prio_data(cfqq, ioc); | |
cdb16e8f | 2930 | cfq_link_cfqq_cfqg(cfqq, cfqg); |
6118b70b JA |
2931 | cfq_log_cfqq(cfqd, cfqq, "alloced"); |
2932 | } else | |
2933 | cfqq = &cfqd->oom_cfqq; | |
22e2c507 JA |
2934 | } |
2935 | ||
2936 | if (new_cfqq) | |
2937 | kmem_cache_free(cfq_pool, new_cfqq); | |
2938 | ||
22e2c507 JA |
2939 | return cfqq; |
2940 | } | |
2941 | ||
c2dea2d1 VT |
2942 | static struct cfq_queue ** |
2943 | cfq_async_queue_prio(struct cfq_data *cfqd, int ioprio_class, int ioprio) | |
2944 | { | |
fe094d98 | 2945 | switch (ioprio_class) { |
c2dea2d1 VT |
2946 | case IOPRIO_CLASS_RT: |
2947 | return &cfqd->async_cfqq[0][ioprio]; | |
2948 | case IOPRIO_CLASS_BE: | |
2949 | return &cfqd->async_cfqq[1][ioprio]; | |
2950 | case IOPRIO_CLASS_IDLE: | |
2951 | return &cfqd->async_idle_cfqq; | |
2952 | default: | |
2953 | BUG(); | |
2954 | } | |
2955 | } | |
2956 | ||
15c31be4 | 2957 | static struct cfq_queue * |
a6151c3a | 2958 | cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct io_context *ioc, |
15c31be4 JA |
2959 | gfp_t gfp_mask) |
2960 | { | |
fd0928df JA |
2961 | const int ioprio = task_ioprio(ioc); |
2962 | const int ioprio_class = task_ioprio_class(ioc); | |
c2dea2d1 | 2963 | struct cfq_queue **async_cfqq = NULL; |
15c31be4 JA |
2964 | struct cfq_queue *cfqq = NULL; |
2965 | ||
c2dea2d1 VT |
2966 | if (!is_sync) { |
2967 | async_cfqq = cfq_async_queue_prio(cfqd, ioprio_class, ioprio); | |
2968 | cfqq = *async_cfqq; | |
2969 | } | |
2970 | ||
6118b70b | 2971 | if (!cfqq) |
fd0928df | 2972 | cfqq = cfq_find_alloc_queue(cfqd, is_sync, ioc, gfp_mask); |
15c31be4 JA |
2973 | |
2974 | /* | |
2975 | * pin the queue now that it's allocated, scheduler exit will prune it | |
2976 | */ | |
c2dea2d1 | 2977 | if (!is_sync && !(*async_cfqq)) { |
30d7b944 | 2978 | cfqq->ref++; |
c2dea2d1 | 2979 | *async_cfqq = cfqq; |
15c31be4 JA |
2980 | } |
2981 | ||
30d7b944 | 2982 | cfqq->ref++; |
15c31be4 JA |
2983 | return cfqq; |
2984 | } | |
2985 | ||
498d3aa2 JA |
2986 | /* |
2987 | * We drop cfq io contexts lazily, so we may find a dead one. | |
2988 | */ | |
dbecf3ab | 2989 | static void |
4ac845a2 JA |
2990 | cfq_drop_dead_cic(struct cfq_data *cfqd, struct io_context *ioc, |
2991 | struct cfq_io_context *cic) | |
dbecf3ab | 2992 | { |
4ac845a2 JA |
2993 | unsigned long flags; |
2994 | ||
fc46379d | 2995 | WARN_ON(!list_empty(&cic->queue_list)); |
bca4b914 | 2996 | BUG_ON(cic->key != cfqd_dead_key(cfqd)); |
597bc485 | 2997 | |
4ac845a2 JA |
2998 | spin_lock_irqsave(&ioc->lock, flags); |
2999 | ||
4faa3c81 | 3000 | BUG_ON(ioc->ioc_data == cic); |
597bc485 | 3001 | |
80b15c73 | 3002 | radix_tree_delete(&ioc->radix_root, cfqd->cic_index); |
ffc4e759 | 3003 | hlist_del_rcu(&cic->cic_list); |
4ac845a2 JA |
3004 | spin_unlock_irqrestore(&ioc->lock, flags); |
3005 | ||
3006 | cfq_cic_free(cic); | |
dbecf3ab OH |
3007 | } |
3008 | ||
e2d74ac0 | 3009 | static struct cfq_io_context * |
4ac845a2 | 3010 | cfq_cic_lookup(struct cfq_data *cfqd, struct io_context *ioc) |
e2d74ac0 | 3011 | { |
e2d74ac0 | 3012 | struct cfq_io_context *cic; |
d6de8be7 | 3013 | unsigned long flags; |
e2d74ac0 | 3014 | |
91fac317 VT |
3015 | if (unlikely(!ioc)) |
3016 | return NULL; | |
3017 | ||
d6de8be7 JA |
3018 | rcu_read_lock(); |
3019 | ||
597bc485 JA |
3020 | /* |
3021 | * we maintain a last-hit cache, to avoid browsing over the tree | |
3022 | */ | |
4ac845a2 | 3023 | cic = rcu_dereference(ioc->ioc_data); |
d6de8be7 JA |
3024 | if (cic && cic->key == cfqd) { |
3025 | rcu_read_unlock(); | |
597bc485 | 3026 | return cic; |
d6de8be7 | 3027 | } |
597bc485 | 3028 | |
4ac845a2 | 3029 | do { |
80b15c73 | 3030 | cic = radix_tree_lookup(&ioc->radix_root, cfqd->cic_index); |
4ac845a2 JA |
3031 | rcu_read_unlock(); |
3032 | if (!cic) | |
3033 | break; | |
bca4b914 | 3034 | if (unlikely(cic->key != cfqd)) { |
4ac845a2 | 3035 | cfq_drop_dead_cic(cfqd, ioc, cic); |
d6de8be7 | 3036 | rcu_read_lock(); |
4ac845a2 | 3037 | continue; |
dbecf3ab | 3038 | } |
e2d74ac0 | 3039 | |
d6de8be7 | 3040 | spin_lock_irqsave(&ioc->lock, flags); |
4ac845a2 | 3041 | rcu_assign_pointer(ioc->ioc_data, cic); |
d6de8be7 | 3042 | spin_unlock_irqrestore(&ioc->lock, flags); |
4ac845a2 JA |
3043 | break; |
3044 | } while (1); | |
e2d74ac0 | 3045 | |
4ac845a2 | 3046 | return cic; |
e2d74ac0 JA |
3047 | } |
3048 | ||
4ac845a2 JA |
3049 | /* |
3050 | * Add cic into ioc, using cfqd as the search key. This enables us to lookup | |
3051 | * the process specific cfq io context when entered from the block layer. | |
3052 | * Also adds the cic to a per-cfqd list, used when this queue is removed. | |
3053 | */ | |
febffd61 JA |
3054 | static int cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc, |
3055 | struct cfq_io_context *cic, gfp_t gfp_mask) | |
e2d74ac0 | 3056 | { |
0261d688 | 3057 | unsigned long flags; |
4ac845a2 | 3058 | int ret; |
e2d74ac0 | 3059 | |
4ac845a2 JA |
3060 | ret = radix_tree_preload(gfp_mask); |
3061 | if (!ret) { | |
3062 | cic->ioc = ioc; | |
3063 | cic->key = cfqd; | |
e2d74ac0 | 3064 | |
4ac845a2 JA |
3065 | spin_lock_irqsave(&ioc->lock, flags); |
3066 | ret = radix_tree_insert(&ioc->radix_root, | |
80b15c73 | 3067 | cfqd->cic_index, cic); |
ffc4e759 JA |
3068 | if (!ret) |
3069 | hlist_add_head_rcu(&cic->cic_list, &ioc->cic_list); | |
4ac845a2 | 3070 | spin_unlock_irqrestore(&ioc->lock, flags); |
e2d74ac0 | 3071 | |
4ac845a2 JA |
3072 | radix_tree_preload_end(); |
3073 | ||
3074 | if (!ret) { | |
3075 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
3076 | list_add(&cic->queue_list, &cfqd->cic_list); | |
3077 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
3078 | } | |
e2d74ac0 JA |
3079 | } |
3080 | ||
4ac845a2 JA |
3081 | if (ret) |
3082 | printk(KERN_ERR "cfq: cic link failed!\n"); | |
fc46379d | 3083 | |
4ac845a2 | 3084 | return ret; |
e2d74ac0 JA |
3085 | } |
3086 | ||
1da177e4 LT |
3087 | /* |
3088 | * Setup general io context and cfq io context. There can be several cfq | |
3089 | * io contexts per general io context, if this process is doing io to more | |
e2d74ac0 | 3090 | * than one device managed by cfq. |
1da177e4 LT |
3091 | */ |
3092 | static struct cfq_io_context * | |
e2d74ac0 | 3093 | cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
1da177e4 | 3094 | { |
22e2c507 | 3095 | struct io_context *ioc = NULL; |
1da177e4 | 3096 | struct cfq_io_context *cic; |
1da177e4 | 3097 | |
22e2c507 | 3098 | might_sleep_if(gfp_mask & __GFP_WAIT); |
1da177e4 | 3099 | |
b5deef90 | 3100 | ioc = get_io_context(gfp_mask, cfqd->queue->node); |
1da177e4 LT |
3101 | if (!ioc) |
3102 | return NULL; | |
3103 | ||
4ac845a2 | 3104 | cic = cfq_cic_lookup(cfqd, ioc); |
e2d74ac0 JA |
3105 | if (cic) |
3106 | goto out; | |
1da177e4 | 3107 | |
e2d74ac0 JA |
3108 | cic = cfq_alloc_io_context(cfqd, gfp_mask); |
3109 | if (cic == NULL) | |
3110 | goto err; | |
1da177e4 | 3111 | |
4ac845a2 JA |
3112 | if (cfq_cic_link(cfqd, ioc, cic, gfp_mask)) |
3113 | goto err_free; | |
3114 | ||
1da177e4 | 3115 | out: |
fc46379d JA |
3116 | smp_read_barrier_depends(); |
3117 | if (unlikely(ioc->ioprio_changed)) | |
3118 | cfq_ioc_set_ioprio(ioc); | |
3119 | ||
24610333 VG |
3120 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
3121 | if (unlikely(ioc->cgroup_changed)) | |
3122 | cfq_ioc_set_cgroup(ioc); | |
3123 | #endif | |
1da177e4 | 3124 | return cic; |
4ac845a2 JA |
3125 | err_free: |
3126 | cfq_cic_free(cic); | |
1da177e4 LT |
3127 | err: |
3128 | put_io_context(ioc); | |
3129 | return NULL; | |
3130 | } | |
3131 | ||
22e2c507 JA |
3132 | static void |
3133 | cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic) | |
1da177e4 | 3134 | { |
aaf1228d JA |
3135 | unsigned long elapsed = jiffies - cic->last_end_request; |
3136 | unsigned long ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle); | |
db3b5848 | 3137 | |
22e2c507 JA |
3138 | cic->ttime_samples = (7*cic->ttime_samples + 256) / 8; |
3139 | cic->ttime_total = (7*cic->ttime_total + 256*ttime) / 8; | |
3140 | cic->ttime_mean = (cic->ttime_total + 128) / cic->ttime_samples; | |
3141 | } | |
1da177e4 | 3142 | |
206dc69b | 3143 | static void |
b2c18e1e | 3144 | cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
6d048f53 | 3145 | struct request *rq) |
206dc69b | 3146 | { |
3dde36dd | 3147 | sector_t sdist = 0; |
41647e7a | 3148 | sector_t n_sec = blk_rq_sectors(rq); |
3dde36dd CZ |
3149 | if (cfqq->last_request_pos) { |
3150 | if (cfqq->last_request_pos < blk_rq_pos(rq)) | |
3151 | sdist = blk_rq_pos(rq) - cfqq->last_request_pos; | |
3152 | else | |
3153 | sdist = cfqq->last_request_pos - blk_rq_pos(rq); | |
3154 | } | |
206dc69b | 3155 | |
3dde36dd | 3156 | cfqq->seek_history <<= 1; |
41647e7a CZ |
3157 | if (blk_queue_nonrot(cfqd->queue)) |
3158 | cfqq->seek_history |= (n_sec < CFQQ_SECT_THR_NONROT); | |
3159 | else | |
3160 | cfqq->seek_history |= (sdist > CFQQ_SEEK_THR); | |
206dc69b | 3161 | } |
1da177e4 | 3162 | |
22e2c507 JA |
3163 | /* |
3164 | * Disable idle window if the process thinks too long or seeks so much that | |
3165 | * it doesn't matter | |
3166 | */ | |
3167 | static void | |
3168 | cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
3169 | struct cfq_io_context *cic) | |
3170 | { | |
7b679138 | 3171 | int old_idle, enable_idle; |
1be92f2f | 3172 | |
0871714e JA |
3173 | /* |
3174 | * Don't idle for async or idle io prio class | |
3175 | */ | |
3176 | if (!cfq_cfqq_sync(cfqq) || cfq_class_idle(cfqq)) | |
1be92f2f JA |
3177 | return; |
3178 | ||
c265a7f4 | 3179 | enable_idle = old_idle = cfq_cfqq_idle_window(cfqq); |
1da177e4 | 3180 | |
76280aff CZ |
3181 | if (cfqq->queued[0] + cfqq->queued[1] >= 4) |
3182 | cfq_mark_cfqq_deep(cfqq); | |
3183 | ||
749ef9f8 CZ |
3184 | if (cfqq->next_rq && (cfqq->next_rq->cmd_flags & REQ_NOIDLE)) |
3185 | enable_idle = 0; | |
3186 | else if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle || | |
3dde36dd | 3187 | (!cfq_cfqq_deep(cfqq) && CFQQ_SEEKY(cfqq))) |
22e2c507 JA |
3188 | enable_idle = 0; |
3189 | else if (sample_valid(cic->ttime_samples)) { | |
718eee05 | 3190 | if (cic->ttime_mean > cfqd->cfq_slice_idle) |
22e2c507 JA |
3191 | enable_idle = 0; |
3192 | else | |
3193 | enable_idle = 1; | |
1da177e4 LT |
3194 | } |
3195 | ||
7b679138 JA |
3196 | if (old_idle != enable_idle) { |
3197 | cfq_log_cfqq(cfqd, cfqq, "idle=%d", enable_idle); | |
3198 | if (enable_idle) | |
3199 | cfq_mark_cfqq_idle_window(cfqq); | |
3200 | else | |
3201 | cfq_clear_cfqq_idle_window(cfqq); | |
3202 | } | |
22e2c507 | 3203 | } |
1da177e4 | 3204 | |
22e2c507 JA |
3205 | /* |
3206 | * Check if new_cfqq should preempt the currently active queue. Return 0 for | |
3207 | * no or if we aren't sure, a 1 will cause a preempt. | |
3208 | */ | |
a6151c3a | 3209 | static bool |
22e2c507 | 3210 | cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, |
5e705374 | 3211 | struct request *rq) |
22e2c507 | 3212 | { |
6d048f53 | 3213 | struct cfq_queue *cfqq; |
22e2c507 | 3214 | |
6d048f53 JA |
3215 | cfqq = cfqd->active_queue; |
3216 | if (!cfqq) | |
a6151c3a | 3217 | return false; |
22e2c507 | 3218 | |
6d048f53 | 3219 | if (cfq_class_idle(new_cfqq)) |
a6151c3a | 3220 | return false; |
22e2c507 JA |
3221 | |
3222 | if (cfq_class_idle(cfqq)) | |
a6151c3a | 3223 | return true; |
1e3335de | 3224 | |
875feb63 DS |
3225 | /* |
3226 | * Don't allow a non-RT request to preempt an ongoing RT cfqq timeslice. | |
3227 | */ | |
3228 | if (cfq_class_rt(cfqq) && !cfq_class_rt(new_cfqq)) | |
3229 | return false; | |
3230 | ||
374f84ac JA |
3231 | /* |
3232 | * if the new request is sync, but the currently running queue is | |
3233 | * not, let the sync request have priority. | |
3234 | */ | |
5e705374 | 3235 | if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq)) |
a6151c3a | 3236 | return true; |
1e3335de | 3237 | |
8682e1f1 VG |
3238 | if (new_cfqq->cfqg != cfqq->cfqg) |
3239 | return false; | |
3240 | ||
3241 | if (cfq_slice_used(cfqq)) | |
3242 | return true; | |
3243 | ||
3244 | /* Allow preemption only if we are idling on sync-noidle tree */ | |
3245 | if (cfqd->serving_type == SYNC_NOIDLE_WORKLOAD && | |
3246 | cfqq_type(new_cfqq) == SYNC_NOIDLE_WORKLOAD && | |
3247 | new_cfqq->service_tree->count == 2 && | |
3248 | RB_EMPTY_ROOT(&cfqq->sort_list)) | |
3249 | return true; | |
3250 | ||
374f84ac JA |
3251 | /* |
3252 | * So both queues are sync. Let the new request get disk time if | |
3253 | * it's a metadata request and the current queue is doing regular IO. | |
3254 | */ | |
7b6d91da | 3255 | if ((rq->cmd_flags & REQ_META) && !cfqq->meta_pending) |
e6ec4fe2 | 3256 | return true; |
22e2c507 | 3257 | |
3a9a3f6c DS |
3258 | /* |
3259 | * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice. | |
3260 | */ | |
3261 | if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq)) | |
a6151c3a | 3262 | return true; |
3a9a3f6c | 3263 | |
d2d59e18 SL |
3264 | /* An idle queue should not be idle now for some reason */ |
3265 | if (RB_EMPTY_ROOT(&cfqq->sort_list) && !cfq_should_idle(cfqd, cfqq)) | |
3266 | return true; | |
3267 | ||
1e3335de | 3268 | if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq)) |
a6151c3a | 3269 | return false; |
1e3335de JA |
3270 | |
3271 | /* | |
3272 | * if this request is as-good as one we would expect from the | |
3273 | * current cfqq, let it preempt | |
3274 | */ | |
e9ce335d | 3275 | if (cfq_rq_close(cfqd, cfqq, rq)) |
a6151c3a | 3276 | return true; |
1e3335de | 3277 | |
a6151c3a | 3278 | return false; |
22e2c507 JA |
3279 | } |
3280 | ||
3281 | /* | |
3282 | * cfqq preempts the active queue. if we allowed preempt with no slice left, | |
3283 | * let it have half of its nominal slice. | |
3284 | */ | |
3285 | static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
3286 | { | |
7b679138 | 3287 | cfq_log_cfqq(cfqd, cfqq, "preempt"); |
e5ff082e | 3288 | cfq_slice_expired(cfqd, 1); |
22e2c507 | 3289 | |
bf572256 JA |
3290 | /* |
3291 | * Put the new queue at the front of the of the current list, | |
3292 | * so we know that it will be selected next. | |
3293 | */ | |
3294 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); | |
edd75ffd JA |
3295 | |
3296 | cfq_service_tree_add(cfqd, cfqq, 1); | |
bf572256 | 3297 | |
44f7c160 JA |
3298 | cfqq->slice_end = 0; |
3299 | cfq_mark_cfqq_slice_new(cfqq); | |
22e2c507 JA |
3300 | } |
3301 | ||
22e2c507 | 3302 | /* |
5e705374 | 3303 | * Called when a new fs request (rq) is added (to cfqq). Check if there's |
22e2c507 JA |
3304 | * something we should do about it |
3305 | */ | |
3306 | static void | |
5e705374 JA |
3307 | cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
3308 | struct request *rq) | |
22e2c507 | 3309 | { |
5e705374 | 3310 | struct cfq_io_context *cic = RQ_CIC(rq); |
12e9fddd | 3311 | |
45333d5a | 3312 | cfqd->rq_queued++; |
7b6d91da | 3313 | if (rq->cmd_flags & REQ_META) |
374f84ac JA |
3314 | cfqq->meta_pending++; |
3315 | ||
9c2c38a1 | 3316 | cfq_update_io_thinktime(cfqd, cic); |
b2c18e1e | 3317 | cfq_update_io_seektime(cfqd, cfqq, rq); |
9c2c38a1 JA |
3318 | cfq_update_idle_window(cfqd, cfqq, cic); |
3319 | ||
b2c18e1e | 3320 | cfqq->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq); |
22e2c507 JA |
3321 | |
3322 | if (cfqq == cfqd->active_queue) { | |
3323 | /* | |
b029195d JA |
3324 | * Remember that we saw a request from this process, but |
3325 | * don't start queuing just yet. Otherwise we risk seeing lots | |
3326 | * of tiny requests, because we disrupt the normal plugging | |
d6ceb25e JA |
3327 | * and merging. If the request is already larger than a single |
3328 | * page, let it rip immediately. For that case we assume that | |
2d870722 JA |
3329 | * merging is already done. Ditto for a busy system that |
3330 | * has other work pending, don't risk delaying until the | |
3331 | * idle timer unplug to continue working. | |
22e2c507 | 3332 | */ |
d6ceb25e | 3333 | if (cfq_cfqq_wait_request(cfqq)) { |
2d870722 JA |
3334 | if (blk_rq_bytes(rq) > PAGE_CACHE_SIZE || |
3335 | cfqd->busy_queues > 1) { | |
812df48d | 3336 | cfq_del_timer(cfqd, cfqq); |
554554f6 | 3337 | cfq_clear_cfqq_wait_request(cfqq); |
bf791937 | 3338 | __blk_run_queue(cfqd->queue); |
a11cdaa7 | 3339 | } else { |
e98ef89b | 3340 | cfq_blkiocg_update_idle_time_stats( |
a11cdaa7 | 3341 | &cfqq->cfqg->blkg); |
bf791937 | 3342 | cfq_mark_cfqq_must_dispatch(cfqq); |
a11cdaa7 | 3343 | } |
d6ceb25e | 3344 | } |
5e705374 | 3345 | } else if (cfq_should_preempt(cfqd, cfqq, rq)) { |
22e2c507 JA |
3346 | /* |
3347 | * not the active queue - expire current slice if it is | |
3348 | * idle and has expired it's mean thinktime or this new queue | |
3a9a3f6c DS |
3349 | * has some old slice time left and is of higher priority or |
3350 | * this new queue is RT and the current one is BE | |
22e2c507 JA |
3351 | */ |
3352 | cfq_preempt_queue(cfqd, cfqq); | |
a7f55792 | 3353 | __blk_run_queue(cfqd->queue); |
22e2c507 | 3354 | } |
1da177e4 LT |
3355 | } |
3356 | ||
165125e1 | 3357 | static void cfq_insert_request(struct request_queue *q, struct request *rq) |
1da177e4 | 3358 | { |
b4878f24 | 3359 | struct cfq_data *cfqd = q->elevator->elevator_data; |
5e705374 | 3360 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 | 3361 | |
7b679138 | 3362 | cfq_log_cfqq(cfqd, cfqq, "insert_request"); |
fd0928df | 3363 | cfq_init_prio_data(cfqq, RQ_CIC(rq)->ioc); |
1da177e4 | 3364 | |
30996f40 | 3365 | rq_set_fifo_time(rq, jiffies + cfqd->cfq_fifo_expire[rq_is_sync(rq)]); |
22e2c507 | 3366 | list_add_tail(&rq->queuelist, &cfqq->fifo); |
aa6f6a3d | 3367 | cfq_add_rq_rb(rq); |
e98ef89b | 3368 | cfq_blkiocg_update_io_add_stats(&(RQ_CFQG(rq))->blkg, |
cdc1184c DS |
3369 | &cfqd->serving_group->blkg, rq_data_dir(rq), |
3370 | rq_is_sync(rq)); | |
5e705374 | 3371 | cfq_rq_enqueued(cfqd, cfqq, rq); |
1da177e4 LT |
3372 | } |
3373 | ||
45333d5a AC |
3374 | /* |
3375 | * Update hw_tag based on peak queue depth over 50 samples under | |
3376 | * sufficient load. | |
3377 | */ | |
3378 | static void cfq_update_hw_tag(struct cfq_data *cfqd) | |
3379 | { | |
1a1238a7 SL |
3380 | struct cfq_queue *cfqq = cfqd->active_queue; |
3381 | ||
53c583d2 CZ |
3382 | if (cfqd->rq_in_driver > cfqd->hw_tag_est_depth) |
3383 | cfqd->hw_tag_est_depth = cfqd->rq_in_driver; | |
e459dd08 CZ |
3384 | |
3385 | if (cfqd->hw_tag == 1) | |
3386 | return; | |
45333d5a AC |
3387 | |
3388 | if (cfqd->rq_queued <= CFQ_HW_QUEUE_MIN && | |
53c583d2 | 3389 | cfqd->rq_in_driver <= CFQ_HW_QUEUE_MIN) |
45333d5a AC |
3390 | return; |
3391 | ||
1a1238a7 SL |
3392 | /* |
3393 | * If active queue hasn't enough requests and can idle, cfq might not | |
3394 | * dispatch sufficient requests to hardware. Don't zero hw_tag in this | |
3395 | * case | |
3396 | */ | |
3397 | if (cfqq && cfq_cfqq_idle_window(cfqq) && | |
3398 | cfqq->dispatched + cfqq->queued[0] + cfqq->queued[1] < | |
53c583d2 | 3399 | CFQ_HW_QUEUE_MIN && cfqd->rq_in_driver < CFQ_HW_QUEUE_MIN) |
1a1238a7 SL |
3400 | return; |
3401 | ||
45333d5a AC |
3402 | if (cfqd->hw_tag_samples++ < 50) |
3403 | return; | |
3404 | ||
e459dd08 | 3405 | if (cfqd->hw_tag_est_depth >= CFQ_HW_QUEUE_MIN) |
45333d5a AC |
3406 | cfqd->hw_tag = 1; |
3407 | else | |
3408 | cfqd->hw_tag = 0; | |
45333d5a AC |
3409 | } |
3410 | ||
7667aa06 VG |
3411 | static bool cfq_should_wait_busy(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
3412 | { | |
3413 | struct cfq_io_context *cic = cfqd->active_cic; | |
3414 | ||
3415 | /* If there are other queues in the group, don't wait */ | |
3416 | if (cfqq->cfqg->nr_cfqq > 1) | |
3417 | return false; | |
3418 | ||
3419 | if (cfq_slice_used(cfqq)) | |
3420 | return true; | |
3421 | ||
3422 | /* if slice left is less than think time, wait busy */ | |
3423 | if (cic && sample_valid(cic->ttime_samples) | |
3424 | && (cfqq->slice_end - jiffies < cic->ttime_mean)) | |
3425 | return true; | |
3426 | ||
3427 | /* | |
3428 | * If think times is less than a jiffy than ttime_mean=0 and above | |
3429 | * will not be true. It might happen that slice has not expired yet | |
3430 | * but will expire soon (4-5 ns) during select_queue(). To cover the | |
3431 | * case where think time is less than a jiffy, mark the queue wait | |
3432 | * busy if only 1 jiffy is left in the slice. | |
3433 | */ | |
3434 | if (cfqq->slice_end - jiffies == 1) | |
3435 | return true; | |
3436 | ||
3437 | return false; | |
3438 | } | |
3439 | ||
165125e1 | 3440 | static void cfq_completed_request(struct request_queue *q, struct request *rq) |
1da177e4 | 3441 | { |
5e705374 | 3442 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
b4878f24 | 3443 | struct cfq_data *cfqd = cfqq->cfqd; |
5380a101 | 3444 | const int sync = rq_is_sync(rq); |
b4878f24 | 3445 | unsigned long now; |
1da177e4 | 3446 | |
b4878f24 | 3447 | now = jiffies; |
33659ebb CH |
3448 | cfq_log_cfqq(cfqd, cfqq, "complete rqnoidle %d", |
3449 | !!(rq->cmd_flags & REQ_NOIDLE)); | |
1da177e4 | 3450 | |
45333d5a AC |
3451 | cfq_update_hw_tag(cfqd); |
3452 | ||
53c583d2 | 3453 | WARN_ON(!cfqd->rq_in_driver); |
6d048f53 | 3454 | WARN_ON(!cfqq->dispatched); |
53c583d2 | 3455 | cfqd->rq_in_driver--; |
6d048f53 | 3456 | cfqq->dispatched--; |
80bdf0c7 | 3457 | (RQ_CFQG(rq))->dispatched--; |
e98ef89b VG |
3458 | cfq_blkiocg_update_completion_stats(&cfqq->cfqg->blkg, |
3459 | rq_start_time_ns(rq), rq_io_start_time_ns(rq), | |
3460 | rq_data_dir(rq), rq_is_sync(rq)); | |
1da177e4 | 3461 | |
53c583d2 | 3462 | cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]--; |
3ed9a296 | 3463 | |
365722bb | 3464 | if (sync) { |
5e705374 | 3465 | RQ_CIC(rq)->last_end_request = now; |
573412b2 CZ |
3466 | if (!time_after(rq->start_time + cfqd->cfq_fifo_expire[1], now)) |
3467 | cfqd->last_delayed_sync = now; | |
365722bb | 3468 | } |
caaa5f9f JA |
3469 | |
3470 | /* | |
3471 | * If this is the active queue, check if it needs to be expired, | |
3472 | * or if we want to idle in case it has no pending requests. | |
3473 | */ | |
3474 | if (cfqd->active_queue == cfqq) { | |
a36e71f9 JA |
3475 | const bool cfqq_empty = RB_EMPTY_ROOT(&cfqq->sort_list); |
3476 | ||
44f7c160 JA |
3477 | if (cfq_cfqq_slice_new(cfqq)) { |
3478 | cfq_set_prio_slice(cfqd, cfqq); | |
3479 | cfq_clear_cfqq_slice_new(cfqq); | |
3480 | } | |
f75edf2d VG |
3481 | |
3482 | /* | |
7667aa06 VG |
3483 | * Should we wait for next request to come in before we expire |
3484 | * the queue. | |
f75edf2d | 3485 | */ |
7667aa06 | 3486 | if (cfq_should_wait_busy(cfqd, cfqq)) { |
80bdf0c7 VG |
3487 | unsigned long extend_sl = cfqd->cfq_slice_idle; |
3488 | if (!cfqd->cfq_slice_idle) | |
3489 | extend_sl = cfqd->cfq_group_idle; | |
3490 | cfqq->slice_end = jiffies + extend_sl; | |
f75edf2d | 3491 | cfq_mark_cfqq_wait_busy(cfqq); |
b1ffe737 | 3492 | cfq_log_cfqq(cfqd, cfqq, "will busy wait"); |
f75edf2d VG |
3493 | } |
3494 | ||
a36e71f9 | 3495 | /* |
8e550632 CZ |
3496 | * Idling is not enabled on: |
3497 | * - expired queues | |
3498 | * - idle-priority queues | |
3499 | * - async queues | |
3500 | * - queues with still some requests queued | |
3501 | * - when there is a close cooperator | |
a36e71f9 | 3502 | */ |
0871714e | 3503 | if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq)) |
e5ff082e | 3504 | cfq_slice_expired(cfqd, 1); |
8e550632 CZ |
3505 | else if (sync && cfqq_empty && |
3506 | !cfq_close_cooperator(cfqd, cfqq)) { | |
749ef9f8 | 3507 | cfq_arm_slice_timer(cfqd); |
8e550632 | 3508 | } |
caaa5f9f | 3509 | } |
6d048f53 | 3510 | |
53c583d2 | 3511 | if (!cfqd->rq_in_driver) |
23e018a1 | 3512 | cfq_schedule_dispatch(cfqd); |
1da177e4 LT |
3513 | } |
3514 | ||
22e2c507 JA |
3515 | /* |
3516 | * we temporarily boost lower priority queues if they are holding fs exclusive | |
3517 | * resources. they are boosted to normal prio (CLASS_BE/4) | |
3518 | */ | |
3519 | static void cfq_prio_boost(struct cfq_queue *cfqq) | |
1da177e4 | 3520 | { |
22e2c507 JA |
3521 | if (has_fs_excl()) { |
3522 | /* | |
3523 | * boost idle prio on transactions that would lock out other | |
3524 | * users of the filesystem | |
3525 | */ | |
3526 | if (cfq_class_idle(cfqq)) | |
3527 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
3528 | if (cfqq->ioprio > IOPRIO_NORM) | |
3529 | cfqq->ioprio = IOPRIO_NORM; | |
3530 | } else { | |
3531 | /* | |
dddb7451 | 3532 | * unboost the queue (if needed) |
22e2c507 | 3533 | */ |
dddb7451 CZ |
3534 | cfqq->ioprio_class = cfqq->org_ioprio_class; |
3535 | cfqq->ioprio = cfqq->org_ioprio; | |
22e2c507 | 3536 | } |
22e2c507 | 3537 | } |
1da177e4 | 3538 | |
89850f7e | 3539 | static inline int __cfq_may_queue(struct cfq_queue *cfqq) |
22e2c507 | 3540 | { |
1b379d8d | 3541 | if (cfq_cfqq_wait_request(cfqq) && !cfq_cfqq_must_alloc_slice(cfqq)) { |
3b18152c | 3542 | cfq_mark_cfqq_must_alloc_slice(cfqq); |
22e2c507 | 3543 | return ELV_MQUEUE_MUST; |
3b18152c | 3544 | } |
1da177e4 | 3545 | |
22e2c507 | 3546 | return ELV_MQUEUE_MAY; |
22e2c507 JA |
3547 | } |
3548 | ||
165125e1 | 3549 | static int cfq_may_queue(struct request_queue *q, int rw) |
22e2c507 JA |
3550 | { |
3551 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
3552 | struct task_struct *tsk = current; | |
91fac317 | 3553 | struct cfq_io_context *cic; |
22e2c507 JA |
3554 | struct cfq_queue *cfqq; |
3555 | ||
3556 | /* | |
3557 | * don't force setup of a queue from here, as a call to may_queue | |
3558 | * does not necessarily imply that a request actually will be queued. | |
3559 | * so just lookup a possibly existing queue, or return 'may queue' | |
3560 | * if that fails | |
3561 | */ | |
4ac845a2 | 3562 | cic = cfq_cic_lookup(cfqd, tsk->io_context); |
91fac317 VT |
3563 | if (!cic) |
3564 | return ELV_MQUEUE_MAY; | |
3565 | ||
b0b78f81 | 3566 | cfqq = cic_to_cfqq(cic, rw_is_sync(rw)); |
22e2c507 | 3567 | if (cfqq) { |
fd0928df | 3568 | cfq_init_prio_data(cfqq, cic->ioc); |
22e2c507 JA |
3569 | cfq_prio_boost(cfqq); |
3570 | ||
89850f7e | 3571 | return __cfq_may_queue(cfqq); |
22e2c507 JA |
3572 | } |
3573 | ||
3574 | return ELV_MQUEUE_MAY; | |
1da177e4 LT |
3575 | } |
3576 | ||
1da177e4 LT |
3577 | /* |
3578 | * queue lock held here | |
3579 | */ | |
bb37b94c | 3580 | static void cfq_put_request(struct request *rq) |
1da177e4 | 3581 | { |
5e705374 | 3582 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
1da177e4 | 3583 | |
5e705374 | 3584 | if (cfqq) { |
22e2c507 | 3585 | const int rw = rq_data_dir(rq); |
1da177e4 | 3586 | |
22e2c507 JA |
3587 | BUG_ON(!cfqq->allocated[rw]); |
3588 | cfqq->allocated[rw]--; | |
1da177e4 | 3589 | |
5e705374 | 3590 | put_io_context(RQ_CIC(rq)->ioc); |
1da177e4 | 3591 | |
1da177e4 | 3592 | rq->elevator_private = NULL; |
5e705374 | 3593 | rq->elevator_private2 = NULL; |
1da177e4 | 3594 | |
7f1dc8a2 VG |
3595 | /* Put down rq reference on cfqg */ |
3596 | cfq_put_cfqg(RQ_CFQG(rq)); | |
3597 | rq->elevator_private3 = NULL; | |
3598 | ||
1da177e4 LT |
3599 | cfq_put_queue(cfqq); |
3600 | } | |
3601 | } | |
3602 | ||
df5fe3e8 JM |
3603 | static struct cfq_queue * |
3604 | cfq_merge_cfqqs(struct cfq_data *cfqd, struct cfq_io_context *cic, | |
3605 | struct cfq_queue *cfqq) | |
3606 | { | |
3607 | cfq_log_cfqq(cfqd, cfqq, "merging with queue %p", cfqq->new_cfqq); | |
3608 | cic_set_cfqq(cic, cfqq->new_cfqq, 1); | |
b3b6d040 | 3609 | cfq_mark_cfqq_coop(cfqq->new_cfqq); |
df5fe3e8 JM |
3610 | cfq_put_queue(cfqq); |
3611 | return cic_to_cfqq(cic, 1); | |
3612 | } | |
3613 | ||
e6c5bc73 JM |
3614 | /* |
3615 | * Returns NULL if a new cfqq should be allocated, or the old cfqq if this | |
3616 | * was the last process referring to said cfqq. | |
3617 | */ | |
3618 | static struct cfq_queue * | |
3619 | split_cfqq(struct cfq_io_context *cic, struct cfq_queue *cfqq) | |
3620 | { | |
3621 | if (cfqq_process_refs(cfqq) == 1) { | |
e6c5bc73 JM |
3622 | cfqq->pid = current->pid; |
3623 | cfq_clear_cfqq_coop(cfqq); | |
ae54abed | 3624 | cfq_clear_cfqq_split_coop(cfqq); |
e6c5bc73 JM |
3625 | return cfqq; |
3626 | } | |
3627 | ||
3628 | cic_set_cfqq(cic, NULL, 1); | |
d02a2c07 SL |
3629 | |
3630 | cfq_put_cooperator(cfqq); | |
3631 | ||
e6c5bc73 JM |
3632 | cfq_put_queue(cfqq); |
3633 | return NULL; | |
3634 | } | |
1da177e4 | 3635 | /* |
22e2c507 | 3636 | * Allocate cfq data structures associated with this request. |
1da177e4 | 3637 | */ |
22e2c507 | 3638 | static int |
165125e1 | 3639 | cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask) |
1da177e4 LT |
3640 | { |
3641 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
3642 | struct cfq_io_context *cic; | |
3643 | const int rw = rq_data_dir(rq); | |
a6151c3a | 3644 | const bool is_sync = rq_is_sync(rq); |
22e2c507 | 3645 | struct cfq_queue *cfqq; |
1da177e4 LT |
3646 | unsigned long flags; |
3647 | ||
3648 | might_sleep_if(gfp_mask & __GFP_WAIT); | |
3649 | ||
e2d74ac0 | 3650 | cic = cfq_get_io_context(cfqd, gfp_mask); |
22e2c507 | 3651 | |
1da177e4 LT |
3652 | spin_lock_irqsave(q->queue_lock, flags); |
3653 | ||
22e2c507 JA |
3654 | if (!cic) |
3655 | goto queue_fail; | |
3656 | ||
e6c5bc73 | 3657 | new_queue: |
91fac317 | 3658 | cfqq = cic_to_cfqq(cic, is_sync); |
32f2e807 | 3659 | if (!cfqq || cfqq == &cfqd->oom_cfqq) { |
fd0928df | 3660 | cfqq = cfq_get_queue(cfqd, is_sync, cic->ioc, gfp_mask); |
91fac317 | 3661 | cic_set_cfqq(cic, cfqq, is_sync); |
df5fe3e8 | 3662 | } else { |
e6c5bc73 JM |
3663 | /* |
3664 | * If the queue was seeky for too long, break it apart. | |
3665 | */ | |
ae54abed | 3666 | if (cfq_cfqq_coop(cfqq) && cfq_cfqq_split_coop(cfqq)) { |
e6c5bc73 JM |
3667 | cfq_log_cfqq(cfqd, cfqq, "breaking apart cfqq"); |
3668 | cfqq = split_cfqq(cic, cfqq); | |
3669 | if (!cfqq) | |
3670 | goto new_queue; | |
3671 | } | |
3672 | ||
df5fe3e8 JM |
3673 | /* |
3674 | * Check to see if this queue is scheduled to merge with | |
3675 | * another, closely cooperating queue. The merging of | |
3676 | * queues happens here as it must be done in process context. | |
3677 | * The reference on new_cfqq was taken in merge_cfqqs. | |
3678 | */ | |
3679 | if (cfqq->new_cfqq) | |
3680 | cfqq = cfq_merge_cfqqs(cfqd, cic, cfqq); | |
91fac317 | 3681 | } |
1da177e4 LT |
3682 | |
3683 | cfqq->allocated[rw]++; | |
30d7b944 | 3684 | cfqq->ref++; |
5e705374 JA |
3685 | rq->elevator_private = cic; |
3686 | rq->elevator_private2 = cfqq; | |
7f1dc8a2 | 3687 | rq->elevator_private3 = cfq_ref_get_cfqg(cfqq->cfqg); |
329a6781 SL |
3688 | |
3689 | spin_unlock_irqrestore(q->queue_lock, flags); | |
3690 | ||
5e705374 | 3691 | return 0; |
1da177e4 | 3692 | |
22e2c507 JA |
3693 | queue_fail: |
3694 | if (cic) | |
3695 | put_io_context(cic->ioc); | |
89850f7e | 3696 | |
23e018a1 | 3697 | cfq_schedule_dispatch(cfqd); |
1da177e4 | 3698 | spin_unlock_irqrestore(q->queue_lock, flags); |
7b679138 | 3699 | cfq_log(cfqd, "set_request fail"); |
1da177e4 LT |
3700 | return 1; |
3701 | } | |
3702 | ||
65f27f38 | 3703 | static void cfq_kick_queue(struct work_struct *work) |
22e2c507 | 3704 | { |
65f27f38 | 3705 | struct cfq_data *cfqd = |
23e018a1 | 3706 | container_of(work, struct cfq_data, unplug_work); |
165125e1 | 3707 | struct request_queue *q = cfqd->queue; |
22e2c507 | 3708 | |
40bb54d1 | 3709 | spin_lock_irq(q->queue_lock); |
a7f55792 | 3710 | __blk_run_queue(cfqd->queue); |
40bb54d1 | 3711 | spin_unlock_irq(q->queue_lock); |
22e2c507 JA |
3712 | } |
3713 | ||
3714 | /* | |
3715 | * Timer running if the active_queue is currently idling inside its time slice | |
3716 | */ | |
3717 | static void cfq_idle_slice_timer(unsigned long data) | |
3718 | { | |
3719 | struct cfq_data *cfqd = (struct cfq_data *) data; | |
3720 | struct cfq_queue *cfqq; | |
3721 | unsigned long flags; | |
3c6bd2f8 | 3722 | int timed_out = 1; |
22e2c507 | 3723 | |
7b679138 JA |
3724 | cfq_log(cfqd, "idle timer fired"); |
3725 | ||
22e2c507 JA |
3726 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); |
3727 | ||
fe094d98 JA |
3728 | cfqq = cfqd->active_queue; |
3729 | if (cfqq) { | |
3c6bd2f8 JA |
3730 | timed_out = 0; |
3731 | ||
b029195d JA |
3732 | /* |
3733 | * We saw a request before the queue expired, let it through | |
3734 | */ | |
3735 | if (cfq_cfqq_must_dispatch(cfqq)) | |
3736 | goto out_kick; | |
3737 | ||
22e2c507 JA |
3738 | /* |
3739 | * expired | |
3740 | */ | |
44f7c160 | 3741 | if (cfq_slice_used(cfqq)) |
22e2c507 JA |
3742 | goto expire; |
3743 | ||
3744 | /* | |
3745 | * only expire and reinvoke request handler, if there are | |
3746 | * other queues with pending requests | |
3747 | */ | |
caaa5f9f | 3748 | if (!cfqd->busy_queues) |
22e2c507 | 3749 | goto out_cont; |
22e2c507 JA |
3750 | |
3751 | /* | |
3752 | * not expired and it has a request pending, let it dispatch | |
3753 | */ | |
75e50984 | 3754 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
22e2c507 | 3755 | goto out_kick; |
76280aff CZ |
3756 | |
3757 | /* | |
3758 | * Queue depth flag is reset only when the idle didn't succeed | |
3759 | */ | |
3760 | cfq_clear_cfqq_deep(cfqq); | |
22e2c507 JA |
3761 | } |
3762 | expire: | |
e5ff082e | 3763 | cfq_slice_expired(cfqd, timed_out); |
22e2c507 | 3764 | out_kick: |
23e018a1 | 3765 | cfq_schedule_dispatch(cfqd); |
22e2c507 JA |
3766 | out_cont: |
3767 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
3768 | } | |
3769 | ||
3b18152c JA |
3770 | static void cfq_shutdown_timer_wq(struct cfq_data *cfqd) |
3771 | { | |
3772 | del_timer_sync(&cfqd->idle_slice_timer); | |
23e018a1 | 3773 | cancel_work_sync(&cfqd->unplug_work); |
3b18152c | 3774 | } |
22e2c507 | 3775 | |
c2dea2d1 VT |
3776 | static void cfq_put_async_queues(struct cfq_data *cfqd) |
3777 | { | |
3778 | int i; | |
3779 | ||
3780 | for (i = 0; i < IOPRIO_BE_NR; i++) { | |
3781 | if (cfqd->async_cfqq[0][i]) | |
3782 | cfq_put_queue(cfqd->async_cfqq[0][i]); | |
3783 | if (cfqd->async_cfqq[1][i]) | |
3784 | cfq_put_queue(cfqd->async_cfqq[1][i]); | |
c2dea2d1 | 3785 | } |
2389d1ef ON |
3786 | |
3787 | if (cfqd->async_idle_cfqq) | |
3788 | cfq_put_queue(cfqd->async_idle_cfqq); | |
c2dea2d1 VT |
3789 | } |
3790 | ||
bb729bc9 JA |
3791 | static void cfq_cfqd_free(struct rcu_head *head) |
3792 | { | |
3793 | kfree(container_of(head, struct cfq_data, rcu)); | |
3794 | } | |
3795 | ||
b374d18a | 3796 | static void cfq_exit_queue(struct elevator_queue *e) |
1da177e4 | 3797 | { |
22e2c507 | 3798 | struct cfq_data *cfqd = e->elevator_data; |
165125e1 | 3799 | struct request_queue *q = cfqd->queue; |
22e2c507 | 3800 | |
3b18152c | 3801 | cfq_shutdown_timer_wq(cfqd); |
e2d74ac0 | 3802 | |
d9ff4187 | 3803 | spin_lock_irq(q->queue_lock); |
e2d74ac0 | 3804 | |
d9ff4187 | 3805 | if (cfqd->active_queue) |
e5ff082e | 3806 | __cfq_slice_expired(cfqd, cfqd->active_queue, 0); |
e2d74ac0 JA |
3807 | |
3808 | while (!list_empty(&cfqd->cic_list)) { | |
d9ff4187 AV |
3809 | struct cfq_io_context *cic = list_entry(cfqd->cic_list.next, |
3810 | struct cfq_io_context, | |
3811 | queue_list); | |
89850f7e JA |
3812 | |
3813 | __cfq_exit_single_io_context(cfqd, cic); | |
d9ff4187 | 3814 | } |
e2d74ac0 | 3815 | |
c2dea2d1 | 3816 | cfq_put_async_queues(cfqd); |
b1c35769 | 3817 | cfq_release_cfq_groups(cfqd); |
e98ef89b | 3818 | cfq_blkiocg_del_blkio_group(&cfqd->root_group.blkg); |
15c31be4 | 3819 | |
d9ff4187 | 3820 | spin_unlock_irq(q->queue_lock); |
a90d742e AV |
3821 | |
3822 | cfq_shutdown_timer_wq(cfqd); | |
3823 | ||
80b15c73 KK |
3824 | spin_lock(&cic_index_lock); |
3825 | ida_remove(&cic_index_ida, cfqd->cic_index); | |
3826 | spin_unlock(&cic_index_lock); | |
3827 | ||
b1c35769 | 3828 | /* Wait for cfqg->blkg->key accessors to exit their grace periods. */ |
bb729bc9 | 3829 | call_rcu(&cfqd->rcu, cfq_cfqd_free); |
1da177e4 LT |
3830 | } |
3831 | ||
80b15c73 KK |
3832 | static int cfq_alloc_cic_index(void) |
3833 | { | |
3834 | int index, error; | |
3835 | ||
3836 | do { | |
3837 | if (!ida_pre_get(&cic_index_ida, GFP_KERNEL)) | |
3838 | return -ENOMEM; | |
3839 | ||
3840 | spin_lock(&cic_index_lock); | |
3841 | error = ida_get_new(&cic_index_ida, &index); | |
3842 | spin_unlock(&cic_index_lock); | |
3843 | if (error && error != -EAGAIN) | |
3844 | return error; | |
3845 | } while (error); | |
3846 | ||
3847 | return index; | |
3848 | } | |
3849 | ||
165125e1 | 3850 | static void *cfq_init_queue(struct request_queue *q) |
1da177e4 LT |
3851 | { |
3852 | struct cfq_data *cfqd; | |
718eee05 | 3853 | int i, j; |
cdb16e8f | 3854 | struct cfq_group *cfqg; |
615f0259 | 3855 | struct cfq_rb_root *st; |
1da177e4 | 3856 | |
80b15c73 KK |
3857 | i = cfq_alloc_cic_index(); |
3858 | if (i < 0) | |
3859 | return NULL; | |
3860 | ||
94f6030c | 3861 | cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL | __GFP_ZERO, q->node); |
1da177e4 | 3862 | if (!cfqd) |
bc1c1169 | 3863 | return NULL; |
1da177e4 | 3864 | |
30d7b944 SL |
3865 | /* |
3866 | * Don't need take queue_lock in the routine, since we are | |
3867 | * initializing the ioscheduler, and nobody is using cfqd | |
3868 | */ | |
80b15c73 KK |
3869 | cfqd->cic_index = i; |
3870 | ||
1fa8f6d6 VG |
3871 | /* Init root service tree */ |
3872 | cfqd->grp_service_tree = CFQ_RB_ROOT; | |
3873 | ||
cdb16e8f VG |
3874 | /* Init root group */ |
3875 | cfqg = &cfqd->root_group; | |
615f0259 VG |
3876 | for_each_cfqg_st(cfqg, i, j, st) |
3877 | *st = CFQ_RB_ROOT; | |
1fa8f6d6 | 3878 | RB_CLEAR_NODE(&cfqg->rb_node); |
26a2ac00 | 3879 | |
25bc6b07 VG |
3880 | /* Give preference to root group over other groups */ |
3881 | cfqg->weight = 2*BLKIO_WEIGHT_DEFAULT; | |
3882 | ||
25fb5169 | 3883 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
b1c35769 VG |
3884 | /* |
3885 | * Take a reference to root group which we never drop. This is just | |
3886 | * to make sure that cfq_put_cfqg() does not try to kfree root group | |
3887 | */ | |
329a6781 | 3888 | cfqg->ref = 1; |
dcf097b2 | 3889 | rcu_read_lock(); |
e98ef89b VG |
3890 | cfq_blkiocg_add_blkio_group(&blkio_root_cgroup, &cfqg->blkg, |
3891 | (void *)cfqd, 0); | |
dcf097b2 | 3892 | rcu_read_unlock(); |
25fb5169 | 3893 | #endif |
26a2ac00 JA |
3894 | /* |
3895 | * Not strictly needed (since RB_ROOT just clears the node and we | |
3896 | * zeroed cfqd on alloc), but better be safe in case someone decides | |
3897 | * to add magic to the rb code | |
3898 | */ | |
3899 | for (i = 0; i < CFQ_PRIO_LISTS; i++) | |
3900 | cfqd->prio_trees[i] = RB_ROOT; | |
3901 | ||
6118b70b JA |
3902 | /* |
3903 | * Our fallback cfqq if cfq_find_alloc_queue() runs into OOM issues. | |
3904 | * Grab a permanent reference to it, so that the normal code flow | |
3905 | * will not attempt to free it. | |
3906 | */ | |
3907 | cfq_init_cfqq(cfqd, &cfqd->oom_cfqq, 1, 0); | |
30d7b944 | 3908 | cfqd->oom_cfqq.ref++; |
cdb16e8f | 3909 | cfq_link_cfqq_cfqg(&cfqd->oom_cfqq, &cfqd->root_group); |
6118b70b | 3910 | |
d9ff4187 | 3911 | INIT_LIST_HEAD(&cfqd->cic_list); |
1da177e4 | 3912 | |
1da177e4 | 3913 | cfqd->queue = q; |
1da177e4 | 3914 | |
22e2c507 JA |
3915 | init_timer(&cfqd->idle_slice_timer); |
3916 | cfqd->idle_slice_timer.function = cfq_idle_slice_timer; | |
3917 | cfqd->idle_slice_timer.data = (unsigned long) cfqd; | |
3918 | ||
23e018a1 | 3919 | INIT_WORK(&cfqd->unplug_work, cfq_kick_queue); |
22e2c507 | 3920 | |
1da177e4 | 3921 | cfqd->cfq_quantum = cfq_quantum; |
22e2c507 JA |
3922 | cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; |
3923 | cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; | |
1da177e4 LT |
3924 | cfqd->cfq_back_max = cfq_back_max; |
3925 | cfqd->cfq_back_penalty = cfq_back_penalty; | |
22e2c507 JA |
3926 | cfqd->cfq_slice[0] = cfq_slice_async; |
3927 | cfqd->cfq_slice[1] = cfq_slice_sync; | |
3928 | cfqd->cfq_slice_async_rq = cfq_slice_async_rq; | |
3929 | cfqd->cfq_slice_idle = cfq_slice_idle; | |
80bdf0c7 | 3930 | cfqd->cfq_group_idle = cfq_group_idle; |
963b72fc | 3931 | cfqd->cfq_latency = 1; |
ae30c286 | 3932 | cfqd->cfq_group_isolation = 0; |
e459dd08 | 3933 | cfqd->hw_tag = -1; |
edc71131 CZ |
3934 | /* |
3935 | * we optimistically start assuming sync ops weren't delayed in last | |
3936 | * second, in order to have larger depth for async operations. | |
3937 | */ | |
573412b2 | 3938 | cfqd->last_delayed_sync = jiffies - HZ; |
bc1c1169 | 3939 | return cfqd; |
1da177e4 LT |
3940 | } |
3941 | ||
3942 | static void cfq_slab_kill(void) | |
3943 | { | |
d6de8be7 JA |
3944 | /* |
3945 | * Caller already ensured that pending RCU callbacks are completed, | |
3946 | * so we should have no busy allocations at this point. | |
3947 | */ | |
1da177e4 LT |
3948 | if (cfq_pool) |
3949 | kmem_cache_destroy(cfq_pool); | |
3950 | if (cfq_ioc_pool) | |
3951 | kmem_cache_destroy(cfq_ioc_pool); | |
3952 | } | |
3953 | ||
3954 | static int __init cfq_slab_setup(void) | |
3955 | { | |
0a31bd5f | 3956 | cfq_pool = KMEM_CACHE(cfq_queue, 0); |
1da177e4 LT |
3957 | if (!cfq_pool) |
3958 | goto fail; | |
3959 | ||
34e6bbf2 | 3960 | cfq_ioc_pool = KMEM_CACHE(cfq_io_context, 0); |
1da177e4 LT |
3961 | if (!cfq_ioc_pool) |
3962 | goto fail; | |
3963 | ||
3964 | return 0; | |
3965 | fail: | |
3966 | cfq_slab_kill(); | |
3967 | return -ENOMEM; | |
3968 | } | |
3969 | ||
1da177e4 LT |
3970 | /* |
3971 | * sysfs parts below --> | |
3972 | */ | |
1da177e4 LT |
3973 | static ssize_t |
3974 | cfq_var_show(unsigned int var, char *page) | |
3975 | { | |
3976 | return sprintf(page, "%d\n", var); | |
3977 | } | |
3978 | ||
3979 | static ssize_t | |
3980 | cfq_var_store(unsigned int *var, const char *page, size_t count) | |
3981 | { | |
3982 | char *p = (char *) page; | |
3983 | ||
3984 | *var = simple_strtoul(p, &p, 10); | |
3985 | return count; | |
3986 | } | |
3987 | ||
1da177e4 | 3988 | #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ |
b374d18a | 3989 | static ssize_t __FUNC(struct elevator_queue *e, char *page) \ |
1da177e4 | 3990 | { \ |
3d1ab40f | 3991 | struct cfq_data *cfqd = e->elevator_data; \ |
1da177e4 LT |
3992 | unsigned int __data = __VAR; \ |
3993 | if (__CONV) \ | |
3994 | __data = jiffies_to_msecs(__data); \ | |
3995 | return cfq_var_show(__data, (page)); \ | |
3996 | } | |
3997 | SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); | |
22e2c507 JA |
3998 | SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1); |
3999 | SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1); | |
e572ec7e AV |
4000 | SHOW_FUNCTION(cfq_back_seek_max_show, cfqd->cfq_back_max, 0); |
4001 | SHOW_FUNCTION(cfq_back_seek_penalty_show, cfqd->cfq_back_penalty, 0); | |
22e2c507 | 4002 | SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1); |
80bdf0c7 | 4003 | SHOW_FUNCTION(cfq_group_idle_show, cfqd->cfq_group_idle, 1); |
22e2c507 JA |
4004 | SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1); |
4005 | SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1); | |
4006 | SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0); | |
963b72fc | 4007 | SHOW_FUNCTION(cfq_low_latency_show, cfqd->cfq_latency, 0); |
ae30c286 | 4008 | SHOW_FUNCTION(cfq_group_isolation_show, cfqd->cfq_group_isolation, 0); |
1da177e4 LT |
4009 | #undef SHOW_FUNCTION |
4010 | ||
4011 | #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ | |
b374d18a | 4012 | static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \ |
1da177e4 | 4013 | { \ |
3d1ab40f | 4014 | struct cfq_data *cfqd = e->elevator_data; \ |
1da177e4 LT |
4015 | unsigned int __data; \ |
4016 | int ret = cfq_var_store(&__data, (page), count); \ | |
4017 | if (__data < (MIN)) \ | |
4018 | __data = (MIN); \ | |
4019 | else if (__data > (MAX)) \ | |
4020 | __data = (MAX); \ | |
4021 | if (__CONV) \ | |
4022 | *(__PTR) = msecs_to_jiffies(__data); \ | |
4023 | else \ | |
4024 | *(__PTR) = __data; \ | |
4025 | return ret; \ | |
4026 | } | |
4027 | STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); | |
fe094d98 JA |
4028 | STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, |
4029 | UINT_MAX, 1); | |
4030 | STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, | |
4031 | UINT_MAX, 1); | |
e572ec7e | 4032 | STORE_FUNCTION(cfq_back_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); |
fe094d98 JA |
4033 | STORE_FUNCTION(cfq_back_seek_penalty_store, &cfqd->cfq_back_penalty, 1, |
4034 | UINT_MAX, 0); | |
22e2c507 | 4035 | STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1); |
80bdf0c7 | 4036 | STORE_FUNCTION(cfq_group_idle_store, &cfqd->cfq_group_idle, 0, UINT_MAX, 1); |
22e2c507 JA |
4037 | STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1); |
4038 | STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1); | |
fe094d98 JA |
4039 | STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, |
4040 | UINT_MAX, 0); | |
963b72fc | 4041 | STORE_FUNCTION(cfq_low_latency_store, &cfqd->cfq_latency, 0, 1, 0); |
ae30c286 | 4042 | STORE_FUNCTION(cfq_group_isolation_store, &cfqd->cfq_group_isolation, 0, 1, 0); |
1da177e4 LT |
4043 | #undef STORE_FUNCTION |
4044 | ||
e572ec7e AV |
4045 | #define CFQ_ATTR(name) \ |
4046 | __ATTR(name, S_IRUGO|S_IWUSR, cfq_##name##_show, cfq_##name##_store) | |
4047 | ||
4048 | static struct elv_fs_entry cfq_attrs[] = { | |
4049 | CFQ_ATTR(quantum), | |
e572ec7e AV |
4050 | CFQ_ATTR(fifo_expire_sync), |
4051 | CFQ_ATTR(fifo_expire_async), | |
4052 | CFQ_ATTR(back_seek_max), | |
4053 | CFQ_ATTR(back_seek_penalty), | |
4054 | CFQ_ATTR(slice_sync), | |
4055 | CFQ_ATTR(slice_async), | |
4056 | CFQ_ATTR(slice_async_rq), | |
4057 | CFQ_ATTR(slice_idle), | |
80bdf0c7 | 4058 | CFQ_ATTR(group_idle), |
963b72fc | 4059 | CFQ_ATTR(low_latency), |
ae30c286 | 4060 | CFQ_ATTR(group_isolation), |
e572ec7e | 4061 | __ATTR_NULL |
1da177e4 LT |
4062 | }; |
4063 | ||
1da177e4 LT |
4064 | static struct elevator_type iosched_cfq = { |
4065 | .ops = { | |
4066 | .elevator_merge_fn = cfq_merge, | |
4067 | .elevator_merged_fn = cfq_merged_request, | |
4068 | .elevator_merge_req_fn = cfq_merged_requests, | |
da775265 | 4069 | .elevator_allow_merge_fn = cfq_allow_merge, |
812d4026 | 4070 | .elevator_bio_merged_fn = cfq_bio_merged, |
b4878f24 | 4071 | .elevator_dispatch_fn = cfq_dispatch_requests, |
1da177e4 | 4072 | .elevator_add_req_fn = cfq_insert_request, |
b4878f24 | 4073 | .elevator_activate_req_fn = cfq_activate_request, |
1da177e4 LT |
4074 | .elevator_deactivate_req_fn = cfq_deactivate_request, |
4075 | .elevator_queue_empty_fn = cfq_queue_empty, | |
4076 | .elevator_completed_req_fn = cfq_completed_request, | |
21183b07 JA |
4077 | .elevator_former_req_fn = elv_rb_former_request, |
4078 | .elevator_latter_req_fn = elv_rb_latter_request, | |
1da177e4 LT |
4079 | .elevator_set_req_fn = cfq_set_request, |
4080 | .elevator_put_req_fn = cfq_put_request, | |
4081 | .elevator_may_queue_fn = cfq_may_queue, | |
4082 | .elevator_init_fn = cfq_init_queue, | |
4083 | .elevator_exit_fn = cfq_exit_queue, | |
fc46379d | 4084 | .trim = cfq_free_io_context, |
1da177e4 | 4085 | }, |
3d1ab40f | 4086 | .elevator_attrs = cfq_attrs, |
1da177e4 LT |
4087 | .elevator_name = "cfq", |
4088 | .elevator_owner = THIS_MODULE, | |
4089 | }; | |
4090 | ||
3e252066 VG |
4091 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
4092 | static struct blkio_policy_type blkio_policy_cfq = { | |
4093 | .ops = { | |
4094 | .blkio_unlink_group_fn = cfq_unlink_blkio_group, | |
4095 | .blkio_update_group_weight_fn = cfq_update_blkio_group_weight, | |
4096 | }, | |
062a644d | 4097 | .plid = BLKIO_POLICY_PROP, |
3e252066 VG |
4098 | }; |
4099 | #else | |
4100 | static struct blkio_policy_type blkio_policy_cfq; | |
4101 | #endif | |
4102 | ||
1da177e4 LT |
4103 | static int __init cfq_init(void) |
4104 | { | |
22e2c507 JA |
4105 | /* |
4106 | * could be 0 on HZ < 1000 setups | |
4107 | */ | |
4108 | if (!cfq_slice_async) | |
4109 | cfq_slice_async = 1; | |
4110 | if (!cfq_slice_idle) | |
4111 | cfq_slice_idle = 1; | |
4112 | ||
80bdf0c7 VG |
4113 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
4114 | if (!cfq_group_idle) | |
4115 | cfq_group_idle = 1; | |
4116 | #else | |
4117 | cfq_group_idle = 0; | |
4118 | #endif | |
1da177e4 LT |
4119 | if (cfq_slab_setup()) |
4120 | return -ENOMEM; | |
4121 | ||
2fdd82bd | 4122 | elv_register(&iosched_cfq); |
3e252066 | 4123 | blkio_policy_register(&blkio_policy_cfq); |
1da177e4 | 4124 | |
2fdd82bd | 4125 | return 0; |
1da177e4 LT |
4126 | } |
4127 | ||
4128 | static void __exit cfq_exit(void) | |
4129 | { | |
6e9a4738 | 4130 | DECLARE_COMPLETION_ONSTACK(all_gone); |
3e252066 | 4131 | blkio_policy_unregister(&blkio_policy_cfq); |
1da177e4 | 4132 | elv_unregister(&iosched_cfq); |
334e94de | 4133 | ioc_gone = &all_gone; |
fba82272 OH |
4134 | /* ioc_gone's update must be visible before reading ioc_count */ |
4135 | smp_wmb(); | |
d6de8be7 JA |
4136 | |
4137 | /* | |
4138 | * this also protects us from entering cfq_slab_kill() with | |
4139 | * pending RCU callbacks | |
4140 | */ | |
245b2e70 | 4141 | if (elv_ioc_count_read(cfq_ioc_count)) |
9a11b4ed | 4142 | wait_for_completion(&all_gone); |
80b15c73 | 4143 | ida_destroy(&cic_index_ida); |
83521d3e | 4144 | cfq_slab_kill(); |
1da177e4 LT |
4145 | } |
4146 | ||
4147 | module_init(cfq_init); | |
4148 | module_exit(cfq_exit); | |
4149 | ||
4150 | MODULE_AUTHOR("Jens Axboe"); | |
4151 | MODULE_LICENSE("GPL"); | |
4152 | MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler"); |