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Commit | Line | Data |
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1da177e4 | 1 | /* |
1da177e4 LT |
2 | * CFQ, or complete fairness queueing, disk scheduler. |
3 | * | |
4 | * Based on ideas from a previously unfinished io | |
5 | * scheduler (round robin per-process disk scheduling) and Andrea Arcangeli. | |
6 | * | |
0fe23479 | 7 | * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk> |
1da177e4 | 8 | */ |
1da177e4 | 9 | #include <linux/module.h> |
1cc9be68 AV |
10 | #include <linux/blkdev.h> |
11 | #include <linux/elevator.h> | |
ad5ebd2f | 12 | #include <linux/jiffies.h> |
1da177e4 | 13 | #include <linux/rbtree.h> |
22e2c507 | 14 | #include <linux/ioprio.h> |
7b679138 | 15 | #include <linux/blktrace_api.h> |
25bc6b07 | 16 | #include "blk-cgroup.h" |
1da177e4 LT |
17 | |
18 | /* | |
19 | * tunables | |
20 | */ | |
fe094d98 JA |
21 | /* max queue in one round of service */ |
22 | static const int cfq_quantum = 4; | |
64100099 | 23 | static const int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 }; |
fe094d98 JA |
24 | /* maximum backwards seek, in KiB */ |
25 | static const int cfq_back_max = 16 * 1024; | |
26 | /* penalty of a backwards seek */ | |
27 | static const int cfq_back_penalty = 2; | |
64100099 | 28 | static const int cfq_slice_sync = HZ / 10; |
3b18152c | 29 | static int cfq_slice_async = HZ / 25; |
64100099 | 30 | static const int cfq_slice_async_rq = 2; |
caaa5f9f | 31 | static int cfq_slice_idle = HZ / 125; |
5db5d642 CZ |
32 | static const int cfq_target_latency = HZ * 3/10; /* 300 ms */ |
33 | static const int cfq_hist_divisor = 4; | |
22e2c507 | 34 | |
d9e7620e | 35 | /* |
0871714e | 36 | * offset from end of service tree |
d9e7620e | 37 | */ |
0871714e | 38 | #define CFQ_IDLE_DELAY (HZ / 5) |
d9e7620e JA |
39 | |
40 | /* | |
41 | * below this threshold, we consider thinktime immediate | |
42 | */ | |
43 | #define CFQ_MIN_TT (2) | |
44 | ||
e6c5bc73 JM |
45 | /* |
46 | * Allow merged cfqqs to perform this amount of seeky I/O before | |
47 | * deciding to break the queues up again. | |
48 | */ | |
49 | #define CFQQ_COOP_TOUT (HZ) | |
50 | ||
22e2c507 | 51 | #define CFQ_SLICE_SCALE (5) |
45333d5a | 52 | #define CFQ_HW_QUEUE_MIN (5) |
25bc6b07 | 53 | #define CFQ_SERVICE_SHIFT 12 |
22e2c507 | 54 | |
fe094d98 JA |
55 | #define RQ_CIC(rq) \ |
56 | ((struct cfq_io_context *) (rq)->elevator_private) | |
7b679138 | 57 | #define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elevator_private2) |
1da177e4 | 58 | |
e18b890b CL |
59 | static struct kmem_cache *cfq_pool; |
60 | static struct kmem_cache *cfq_ioc_pool; | |
1da177e4 | 61 | |
245b2e70 | 62 | static DEFINE_PER_CPU(unsigned long, cfq_ioc_count); |
334e94de | 63 | static struct completion *ioc_gone; |
9a11b4ed | 64 | static DEFINE_SPINLOCK(ioc_gone_lock); |
334e94de | 65 | |
22e2c507 JA |
66 | #define CFQ_PRIO_LISTS IOPRIO_BE_NR |
67 | #define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE) | |
22e2c507 JA |
68 | #define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT) |
69 | ||
206dc69b | 70 | #define sample_valid(samples) ((samples) > 80) |
1fa8f6d6 | 71 | #define rb_entry_cfqg(node) rb_entry((node), struct cfq_group, rb_node) |
206dc69b | 72 | |
cc09e299 JA |
73 | /* |
74 | * Most of our rbtree usage is for sorting with min extraction, so | |
75 | * if we cache the leftmost node we don't have to walk down the tree | |
76 | * to find it. Idea borrowed from Ingo Molnars CFS scheduler. We should | |
77 | * move this into the elevator for the rq sorting as well. | |
78 | */ | |
79 | struct cfq_rb_root { | |
80 | struct rb_root rb; | |
81 | struct rb_node *left; | |
aa6f6a3d | 82 | unsigned count; |
1fa8f6d6 | 83 | u64 min_vdisktime; |
25bc6b07 | 84 | struct rb_node *active; |
58ff82f3 | 85 | unsigned total_weight; |
cc09e299 | 86 | }; |
1fa8f6d6 | 87 | #define CFQ_RB_ROOT (struct cfq_rb_root) { RB_ROOT, NULL, 0, 0, } |
cc09e299 | 88 | |
6118b70b JA |
89 | /* |
90 | * Per process-grouping structure | |
91 | */ | |
92 | struct cfq_queue { | |
93 | /* reference count */ | |
94 | atomic_t ref; | |
95 | /* various state flags, see below */ | |
96 | unsigned int flags; | |
97 | /* parent cfq_data */ | |
98 | struct cfq_data *cfqd; | |
99 | /* service_tree member */ | |
100 | struct rb_node rb_node; | |
101 | /* service_tree key */ | |
102 | unsigned long rb_key; | |
103 | /* prio tree member */ | |
104 | struct rb_node p_node; | |
105 | /* prio tree root we belong to, if any */ | |
106 | struct rb_root *p_root; | |
107 | /* sorted list of pending requests */ | |
108 | struct rb_root sort_list; | |
109 | /* if fifo isn't expired, next request to serve */ | |
110 | struct request *next_rq; | |
111 | /* requests queued in sort_list */ | |
112 | int queued[2]; | |
113 | /* currently allocated requests */ | |
114 | int allocated[2]; | |
115 | /* fifo list of requests in sort_list */ | |
116 | struct list_head fifo; | |
117 | ||
dae739eb VG |
118 | /* time when queue got scheduled in to dispatch first request. */ |
119 | unsigned long dispatch_start; | |
f75edf2d | 120 | unsigned int allocated_slice; |
dae739eb VG |
121 | /* time when first request from queue completed and slice started. */ |
122 | unsigned long slice_start; | |
6118b70b JA |
123 | unsigned long slice_end; |
124 | long slice_resid; | |
125 | unsigned int slice_dispatch; | |
126 | ||
127 | /* pending metadata requests */ | |
128 | int meta_pending; | |
129 | /* number of requests that are on the dispatch list or inside driver */ | |
130 | int dispatched; | |
131 | ||
132 | /* io prio of this group */ | |
133 | unsigned short ioprio, org_ioprio; | |
134 | unsigned short ioprio_class, org_ioprio_class; | |
135 | ||
b2c18e1e JM |
136 | unsigned int seek_samples; |
137 | u64 seek_total; | |
138 | sector_t seek_mean; | |
139 | sector_t last_request_pos; | |
e6c5bc73 | 140 | unsigned long seeky_start; |
b2c18e1e | 141 | |
6118b70b | 142 | pid_t pid; |
df5fe3e8 | 143 | |
aa6f6a3d | 144 | struct cfq_rb_root *service_tree; |
df5fe3e8 | 145 | struct cfq_queue *new_cfqq; |
cdb16e8f | 146 | struct cfq_group *cfqg; |
ae30c286 | 147 | struct cfq_group *orig_cfqg; |
22084190 VG |
148 | /* Sectors dispatched in current dispatch round */ |
149 | unsigned long nr_sectors; | |
6118b70b JA |
150 | }; |
151 | ||
c0324a02 | 152 | /* |
718eee05 | 153 | * First index in the service_trees. |
c0324a02 CZ |
154 | * IDLE is handled separately, so it has negative index |
155 | */ | |
156 | enum wl_prio_t { | |
c0324a02 | 157 | BE_WORKLOAD = 0, |
615f0259 VG |
158 | RT_WORKLOAD = 1, |
159 | IDLE_WORKLOAD = 2, | |
c0324a02 CZ |
160 | }; |
161 | ||
718eee05 CZ |
162 | /* |
163 | * Second index in the service_trees. | |
164 | */ | |
165 | enum wl_type_t { | |
166 | ASYNC_WORKLOAD = 0, | |
167 | SYNC_NOIDLE_WORKLOAD = 1, | |
168 | SYNC_WORKLOAD = 2 | |
169 | }; | |
170 | ||
cdb16e8f VG |
171 | /* This is per cgroup per device grouping structure */ |
172 | struct cfq_group { | |
1fa8f6d6 VG |
173 | /* group service_tree member */ |
174 | struct rb_node rb_node; | |
175 | ||
176 | /* group service_tree key */ | |
177 | u64 vdisktime; | |
25bc6b07 | 178 | unsigned int weight; |
1fa8f6d6 VG |
179 | bool on_st; |
180 | ||
181 | /* number of cfqq currently on this group */ | |
182 | int nr_cfqq; | |
183 | ||
58ff82f3 VG |
184 | /* Per group busy queus average. Useful for workload slice calc. */ |
185 | unsigned int busy_queues_avg[2]; | |
cdb16e8f VG |
186 | /* |
187 | * rr lists of queues with requests, onle rr for each priority class. | |
188 | * Counts are embedded in the cfq_rb_root | |
189 | */ | |
190 | struct cfq_rb_root service_trees[2][3]; | |
191 | struct cfq_rb_root service_tree_idle; | |
dae739eb VG |
192 | |
193 | unsigned long saved_workload_slice; | |
194 | enum wl_type_t saved_workload; | |
195 | enum wl_prio_t saved_serving_prio; | |
25fb5169 VG |
196 | struct blkio_group blkg; |
197 | #ifdef CONFIG_CFQ_GROUP_IOSCHED | |
198 | struct hlist_node cfqd_node; | |
b1c35769 | 199 | atomic_t ref; |
25fb5169 | 200 | #endif |
cdb16e8f | 201 | }; |
718eee05 | 202 | |
22e2c507 JA |
203 | /* |
204 | * Per block device queue structure | |
205 | */ | |
1da177e4 | 206 | struct cfq_data { |
165125e1 | 207 | struct request_queue *queue; |
1fa8f6d6 VG |
208 | /* Root service tree for cfq_groups */ |
209 | struct cfq_rb_root grp_service_tree; | |
cdb16e8f | 210 | struct cfq_group root_group; |
22e2c507 | 211 | |
c0324a02 CZ |
212 | /* |
213 | * The priority currently being served | |
22e2c507 | 214 | */ |
c0324a02 | 215 | enum wl_prio_t serving_prio; |
718eee05 CZ |
216 | enum wl_type_t serving_type; |
217 | unsigned long workload_expires; | |
cdb16e8f | 218 | struct cfq_group *serving_group; |
8e550632 | 219 | bool noidle_tree_requires_idle; |
a36e71f9 JA |
220 | |
221 | /* | |
222 | * Each priority tree is sorted by next_request position. These | |
223 | * trees are used when determining if two or more queues are | |
224 | * interleaving requests (see cfq_close_cooperator). | |
225 | */ | |
226 | struct rb_root prio_trees[CFQ_PRIO_LISTS]; | |
227 | ||
22e2c507 JA |
228 | unsigned int busy_queues; |
229 | ||
5ad531db | 230 | int rq_in_driver[2]; |
3ed9a296 | 231 | int sync_flight; |
45333d5a AC |
232 | |
233 | /* | |
234 | * queue-depth detection | |
235 | */ | |
236 | int rq_queued; | |
25776e35 | 237 | int hw_tag; |
e459dd08 CZ |
238 | /* |
239 | * hw_tag can be | |
240 | * -1 => indeterminate, (cfq will behave as if NCQ is present, to allow better detection) | |
241 | * 1 => NCQ is present (hw_tag_est_depth is the estimated max depth) | |
242 | * 0 => no NCQ | |
243 | */ | |
244 | int hw_tag_est_depth; | |
245 | unsigned int hw_tag_samples; | |
1da177e4 | 246 | |
22e2c507 JA |
247 | /* |
248 | * idle window management | |
249 | */ | |
250 | struct timer_list idle_slice_timer; | |
23e018a1 | 251 | struct work_struct unplug_work; |
1da177e4 | 252 | |
22e2c507 JA |
253 | struct cfq_queue *active_queue; |
254 | struct cfq_io_context *active_cic; | |
22e2c507 | 255 | |
c2dea2d1 VT |
256 | /* |
257 | * async queue for each priority case | |
258 | */ | |
259 | struct cfq_queue *async_cfqq[2][IOPRIO_BE_NR]; | |
260 | struct cfq_queue *async_idle_cfqq; | |
15c31be4 | 261 | |
6d048f53 | 262 | sector_t last_position; |
1da177e4 | 263 | |
1da177e4 LT |
264 | /* |
265 | * tunables, see top of file | |
266 | */ | |
267 | unsigned int cfq_quantum; | |
22e2c507 | 268 | unsigned int cfq_fifo_expire[2]; |
1da177e4 LT |
269 | unsigned int cfq_back_penalty; |
270 | unsigned int cfq_back_max; | |
22e2c507 JA |
271 | unsigned int cfq_slice[2]; |
272 | unsigned int cfq_slice_async_rq; | |
273 | unsigned int cfq_slice_idle; | |
963b72fc | 274 | unsigned int cfq_latency; |
ae30c286 | 275 | unsigned int cfq_group_isolation; |
d9ff4187 AV |
276 | |
277 | struct list_head cic_list; | |
1da177e4 | 278 | |
6118b70b JA |
279 | /* |
280 | * Fallback dummy cfqq for extreme OOM conditions | |
281 | */ | |
282 | struct cfq_queue oom_cfqq; | |
365722bb | 283 | |
573412b2 | 284 | unsigned long last_delayed_sync; |
25fb5169 VG |
285 | |
286 | /* List of cfq groups being managed on this device*/ | |
287 | struct hlist_head cfqg_list; | |
bb729bc9 | 288 | struct rcu_head rcu; |
1da177e4 LT |
289 | }; |
290 | ||
25fb5169 VG |
291 | static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd); |
292 | ||
cdb16e8f VG |
293 | static struct cfq_rb_root *service_tree_for(struct cfq_group *cfqg, |
294 | enum wl_prio_t prio, | |
65b32a57 | 295 | enum wl_type_t type) |
c0324a02 | 296 | { |
1fa8f6d6 VG |
297 | if (!cfqg) |
298 | return NULL; | |
299 | ||
c0324a02 | 300 | if (prio == IDLE_WORKLOAD) |
cdb16e8f | 301 | return &cfqg->service_tree_idle; |
c0324a02 | 302 | |
cdb16e8f | 303 | return &cfqg->service_trees[prio][type]; |
c0324a02 CZ |
304 | } |
305 | ||
3b18152c | 306 | enum cfqq_state_flags { |
b0b8d749 JA |
307 | CFQ_CFQQ_FLAG_on_rr = 0, /* on round-robin busy list */ |
308 | CFQ_CFQQ_FLAG_wait_request, /* waiting for a request */ | |
b029195d | 309 | CFQ_CFQQ_FLAG_must_dispatch, /* must be allowed a dispatch */ |
b0b8d749 | 310 | CFQ_CFQQ_FLAG_must_alloc_slice, /* per-slice must_alloc flag */ |
b0b8d749 JA |
311 | CFQ_CFQQ_FLAG_fifo_expire, /* FIFO checked in this slice */ |
312 | CFQ_CFQQ_FLAG_idle_window, /* slice idling enabled */ | |
313 | CFQ_CFQQ_FLAG_prio_changed, /* task priority has changed */ | |
44f7c160 | 314 | CFQ_CFQQ_FLAG_slice_new, /* no requests dispatched in slice */ |
91fac317 | 315 | CFQ_CFQQ_FLAG_sync, /* synchronous queue */ |
b3b6d040 | 316 | CFQ_CFQQ_FLAG_coop, /* cfqq is shared */ |
76280aff | 317 | CFQ_CFQQ_FLAG_deep, /* sync cfqq experienced large depth */ |
f75edf2d | 318 | CFQ_CFQQ_FLAG_wait_busy, /* Waiting for next request */ |
3b18152c JA |
319 | }; |
320 | ||
321 | #define CFQ_CFQQ_FNS(name) \ | |
322 | static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \ | |
323 | { \ | |
fe094d98 | 324 | (cfqq)->flags |= (1 << CFQ_CFQQ_FLAG_##name); \ |
3b18152c JA |
325 | } \ |
326 | static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \ | |
327 | { \ | |
fe094d98 | 328 | (cfqq)->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \ |
3b18152c JA |
329 | } \ |
330 | static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \ | |
331 | { \ | |
fe094d98 | 332 | return ((cfqq)->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \ |
3b18152c JA |
333 | } |
334 | ||
335 | CFQ_CFQQ_FNS(on_rr); | |
336 | CFQ_CFQQ_FNS(wait_request); | |
b029195d | 337 | CFQ_CFQQ_FNS(must_dispatch); |
3b18152c | 338 | CFQ_CFQQ_FNS(must_alloc_slice); |
3b18152c JA |
339 | CFQ_CFQQ_FNS(fifo_expire); |
340 | CFQ_CFQQ_FNS(idle_window); | |
341 | CFQ_CFQQ_FNS(prio_changed); | |
44f7c160 | 342 | CFQ_CFQQ_FNS(slice_new); |
91fac317 | 343 | CFQ_CFQQ_FNS(sync); |
a36e71f9 | 344 | CFQ_CFQQ_FNS(coop); |
76280aff | 345 | CFQ_CFQQ_FNS(deep); |
f75edf2d | 346 | CFQ_CFQQ_FNS(wait_busy); |
3b18152c JA |
347 | #undef CFQ_CFQQ_FNS |
348 | ||
2868ef7b VG |
349 | #ifdef CONFIG_DEBUG_CFQ_IOSCHED |
350 | #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \ | |
351 | blk_add_trace_msg((cfqd)->queue, "cfq%d%c %s " fmt, (cfqq)->pid, \ | |
352 | cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \ | |
353 | blkg_path(&(cfqq)->cfqg->blkg), ##args); | |
354 | ||
355 | #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) \ | |
356 | blk_add_trace_msg((cfqd)->queue, "%s " fmt, \ | |
357 | blkg_path(&(cfqg)->blkg), ##args); \ | |
358 | ||
359 | #else | |
7b679138 JA |
360 | #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \ |
361 | blk_add_trace_msg((cfqd)->queue, "cfq%d " fmt, (cfqq)->pid, ##args) | |
2868ef7b VG |
362 | #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) do {} while (0); |
363 | #endif | |
7b679138 JA |
364 | #define cfq_log(cfqd, fmt, args...) \ |
365 | blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args) | |
366 | ||
615f0259 VG |
367 | /* Traverses through cfq group service trees */ |
368 | #define for_each_cfqg_st(cfqg, i, j, st) \ | |
369 | for (i = 0; i <= IDLE_WORKLOAD; i++) \ | |
370 | for (j = 0, st = i < IDLE_WORKLOAD ? &cfqg->service_trees[i][j]\ | |
371 | : &cfqg->service_tree_idle; \ | |
372 | (i < IDLE_WORKLOAD && j <= SYNC_WORKLOAD) || \ | |
373 | (i == IDLE_WORKLOAD && j == 0); \ | |
374 | j++, st = i < IDLE_WORKLOAD ? \ | |
375 | &cfqg->service_trees[i][j]: NULL) \ | |
376 | ||
377 | ||
c0324a02 CZ |
378 | static inline enum wl_prio_t cfqq_prio(struct cfq_queue *cfqq) |
379 | { | |
380 | if (cfq_class_idle(cfqq)) | |
381 | return IDLE_WORKLOAD; | |
382 | if (cfq_class_rt(cfqq)) | |
383 | return RT_WORKLOAD; | |
384 | return BE_WORKLOAD; | |
385 | } | |
386 | ||
718eee05 CZ |
387 | |
388 | static enum wl_type_t cfqq_type(struct cfq_queue *cfqq) | |
389 | { | |
390 | if (!cfq_cfqq_sync(cfqq)) | |
391 | return ASYNC_WORKLOAD; | |
392 | if (!cfq_cfqq_idle_window(cfqq)) | |
393 | return SYNC_NOIDLE_WORKLOAD; | |
394 | return SYNC_WORKLOAD; | |
395 | } | |
396 | ||
58ff82f3 VG |
397 | static inline int cfq_group_busy_queues_wl(enum wl_prio_t wl, |
398 | struct cfq_data *cfqd, | |
399 | struct cfq_group *cfqg) | |
c0324a02 CZ |
400 | { |
401 | if (wl == IDLE_WORKLOAD) | |
cdb16e8f | 402 | return cfqg->service_tree_idle.count; |
c0324a02 | 403 | |
cdb16e8f VG |
404 | return cfqg->service_trees[wl][ASYNC_WORKLOAD].count |
405 | + cfqg->service_trees[wl][SYNC_NOIDLE_WORKLOAD].count | |
406 | + cfqg->service_trees[wl][SYNC_WORKLOAD].count; | |
c0324a02 CZ |
407 | } |
408 | ||
f26bd1f0 VG |
409 | static inline int cfqg_busy_async_queues(struct cfq_data *cfqd, |
410 | struct cfq_group *cfqg) | |
411 | { | |
412 | return cfqg->service_trees[RT_WORKLOAD][ASYNC_WORKLOAD].count | |
413 | + cfqg->service_trees[BE_WORKLOAD][ASYNC_WORKLOAD].count; | |
414 | } | |
415 | ||
165125e1 | 416 | static void cfq_dispatch_insert(struct request_queue *, struct request *); |
a6151c3a | 417 | static struct cfq_queue *cfq_get_queue(struct cfq_data *, bool, |
fd0928df | 418 | struct io_context *, gfp_t); |
4ac845a2 | 419 | static struct cfq_io_context *cfq_cic_lookup(struct cfq_data *, |
91fac317 VT |
420 | struct io_context *); |
421 | ||
5ad531db JA |
422 | static inline int rq_in_driver(struct cfq_data *cfqd) |
423 | { | |
424 | return cfqd->rq_in_driver[0] + cfqd->rq_in_driver[1]; | |
425 | } | |
426 | ||
91fac317 | 427 | static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_context *cic, |
a6151c3a | 428 | bool is_sync) |
91fac317 | 429 | { |
a6151c3a | 430 | return cic->cfqq[is_sync]; |
91fac317 VT |
431 | } |
432 | ||
433 | static inline void cic_set_cfqq(struct cfq_io_context *cic, | |
a6151c3a | 434 | struct cfq_queue *cfqq, bool is_sync) |
91fac317 | 435 | { |
a6151c3a | 436 | cic->cfqq[is_sync] = cfqq; |
91fac317 VT |
437 | } |
438 | ||
439 | /* | |
440 | * We regard a request as SYNC, if it's either a read or has the SYNC bit | |
441 | * set (in which case it could also be direct WRITE). | |
442 | */ | |
a6151c3a | 443 | static inline bool cfq_bio_sync(struct bio *bio) |
91fac317 | 444 | { |
a6151c3a | 445 | return bio_data_dir(bio) == READ || bio_rw_flagged(bio, BIO_RW_SYNCIO); |
91fac317 | 446 | } |
1da177e4 | 447 | |
99f95e52 AM |
448 | /* |
449 | * scheduler run of queue, if there are requests pending and no one in the | |
450 | * driver that will restart queueing | |
451 | */ | |
23e018a1 | 452 | static inline void cfq_schedule_dispatch(struct cfq_data *cfqd) |
99f95e52 | 453 | { |
7b679138 JA |
454 | if (cfqd->busy_queues) { |
455 | cfq_log(cfqd, "schedule dispatch"); | |
23e018a1 | 456 | kblockd_schedule_work(cfqd->queue, &cfqd->unplug_work); |
7b679138 | 457 | } |
99f95e52 AM |
458 | } |
459 | ||
165125e1 | 460 | static int cfq_queue_empty(struct request_queue *q) |
99f95e52 AM |
461 | { |
462 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
463 | ||
f04a6424 | 464 | return !cfqd->rq_queued; |
99f95e52 AM |
465 | } |
466 | ||
44f7c160 JA |
467 | /* |
468 | * Scale schedule slice based on io priority. Use the sync time slice only | |
469 | * if a queue is marked sync and has sync io queued. A sync queue with async | |
470 | * io only, should not get full sync slice length. | |
471 | */ | |
a6151c3a | 472 | static inline int cfq_prio_slice(struct cfq_data *cfqd, bool sync, |
d9e7620e | 473 | unsigned short prio) |
44f7c160 | 474 | { |
d9e7620e | 475 | const int base_slice = cfqd->cfq_slice[sync]; |
44f7c160 | 476 | |
d9e7620e JA |
477 | WARN_ON(prio >= IOPRIO_BE_NR); |
478 | ||
479 | return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - prio)); | |
480 | } | |
44f7c160 | 481 | |
d9e7620e JA |
482 | static inline int |
483 | cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
484 | { | |
485 | return cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio); | |
44f7c160 JA |
486 | } |
487 | ||
25bc6b07 VG |
488 | static inline u64 cfq_scale_slice(unsigned long delta, struct cfq_group *cfqg) |
489 | { | |
490 | u64 d = delta << CFQ_SERVICE_SHIFT; | |
491 | ||
492 | d = d * BLKIO_WEIGHT_DEFAULT; | |
493 | do_div(d, cfqg->weight); | |
494 | return d; | |
495 | } | |
496 | ||
497 | static inline u64 max_vdisktime(u64 min_vdisktime, u64 vdisktime) | |
498 | { | |
499 | s64 delta = (s64)(vdisktime - min_vdisktime); | |
500 | if (delta > 0) | |
501 | min_vdisktime = vdisktime; | |
502 | ||
503 | return min_vdisktime; | |
504 | } | |
505 | ||
506 | static inline u64 min_vdisktime(u64 min_vdisktime, u64 vdisktime) | |
507 | { | |
508 | s64 delta = (s64)(vdisktime - min_vdisktime); | |
509 | if (delta < 0) | |
510 | min_vdisktime = vdisktime; | |
511 | ||
512 | return min_vdisktime; | |
513 | } | |
514 | ||
515 | static void update_min_vdisktime(struct cfq_rb_root *st) | |
516 | { | |
517 | u64 vdisktime = st->min_vdisktime; | |
518 | struct cfq_group *cfqg; | |
519 | ||
520 | if (st->active) { | |
521 | cfqg = rb_entry_cfqg(st->active); | |
522 | vdisktime = cfqg->vdisktime; | |
523 | } | |
524 | ||
525 | if (st->left) { | |
526 | cfqg = rb_entry_cfqg(st->left); | |
527 | vdisktime = min_vdisktime(vdisktime, cfqg->vdisktime); | |
528 | } | |
529 | ||
530 | st->min_vdisktime = max_vdisktime(st->min_vdisktime, vdisktime); | |
531 | } | |
532 | ||
5db5d642 CZ |
533 | /* |
534 | * get averaged number of queues of RT/BE priority. | |
535 | * average is updated, with a formula that gives more weight to higher numbers, | |
536 | * to quickly follows sudden increases and decrease slowly | |
537 | */ | |
538 | ||
58ff82f3 VG |
539 | static inline unsigned cfq_group_get_avg_queues(struct cfq_data *cfqd, |
540 | struct cfq_group *cfqg, bool rt) | |
5869619c | 541 | { |
5db5d642 CZ |
542 | unsigned min_q, max_q; |
543 | unsigned mult = cfq_hist_divisor - 1; | |
544 | unsigned round = cfq_hist_divisor / 2; | |
58ff82f3 | 545 | unsigned busy = cfq_group_busy_queues_wl(rt, cfqd, cfqg); |
5db5d642 | 546 | |
58ff82f3 VG |
547 | min_q = min(cfqg->busy_queues_avg[rt], busy); |
548 | max_q = max(cfqg->busy_queues_avg[rt], busy); | |
549 | cfqg->busy_queues_avg[rt] = (mult * max_q + min_q + round) / | |
5db5d642 | 550 | cfq_hist_divisor; |
58ff82f3 VG |
551 | return cfqg->busy_queues_avg[rt]; |
552 | } | |
553 | ||
554 | static inline unsigned | |
555 | cfq_group_slice(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
556 | { | |
557 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
558 | ||
559 | return cfq_target_latency * cfqg->weight / st->total_weight; | |
5db5d642 CZ |
560 | } |
561 | ||
44f7c160 JA |
562 | static inline void |
563 | cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
564 | { | |
5db5d642 CZ |
565 | unsigned slice = cfq_prio_to_slice(cfqd, cfqq); |
566 | if (cfqd->cfq_latency) { | |
58ff82f3 VG |
567 | /* |
568 | * interested queues (we consider only the ones with the same | |
569 | * priority class in the cfq group) | |
570 | */ | |
571 | unsigned iq = cfq_group_get_avg_queues(cfqd, cfqq->cfqg, | |
572 | cfq_class_rt(cfqq)); | |
5db5d642 CZ |
573 | unsigned sync_slice = cfqd->cfq_slice[1]; |
574 | unsigned expect_latency = sync_slice * iq; | |
58ff82f3 VG |
575 | unsigned group_slice = cfq_group_slice(cfqd, cfqq->cfqg); |
576 | ||
577 | if (expect_latency > group_slice) { | |
5db5d642 CZ |
578 | unsigned base_low_slice = 2 * cfqd->cfq_slice_idle; |
579 | /* scale low_slice according to IO priority | |
580 | * and sync vs async */ | |
581 | unsigned low_slice = | |
582 | min(slice, base_low_slice * slice / sync_slice); | |
583 | /* the adapted slice value is scaled to fit all iqs | |
584 | * into the target latency */ | |
58ff82f3 | 585 | slice = max(slice * group_slice / expect_latency, |
5db5d642 CZ |
586 | low_slice); |
587 | } | |
588 | } | |
dae739eb | 589 | cfqq->slice_start = jiffies; |
5db5d642 | 590 | cfqq->slice_end = jiffies + slice; |
f75edf2d | 591 | cfqq->allocated_slice = slice; |
7b679138 | 592 | cfq_log_cfqq(cfqd, cfqq, "set_slice=%lu", cfqq->slice_end - jiffies); |
44f7c160 JA |
593 | } |
594 | ||
595 | /* | |
596 | * We need to wrap this check in cfq_cfqq_slice_new(), since ->slice_end | |
597 | * isn't valid until the first request from the dispatch is activated | |
598 | * and the slice time set. | |
599 | */ | |
a6151c3a | 600 | static inline bool cfq_slice_used(struct cfq_queue *cfqq) |
44f7c160 JA |
601 | { |
602 | if (cfq_cfqq_slice_new(cfqq)) | |
603 | return 0; | |
604 | if (time_before(jiffies, cfqq->slice_end)) | |
605 | return 0; | |
606 | ||
607 | return 1; | |
608 | } | |
609 | ||
1da177e4 | 610 | /* |
5e705374 | 611 | * Lifted from AS - choose which of rq1 and rq2 that is best served now. |
1da177e4 | 612 | * We choose the request that is closest to the head right now. Distance |
e8a99053 | 613 | * behind the head is penalized and only allowed to a certain extent. |
1da177e4 | 614 | */ |
5e705374 | 615 | static struct request * |
cf7c25cf | 616 | cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2, sector_t last) |
1da177e4 | 617 | { |
cf7c25cf | 618 | sector_t s1, s2, d1 = 0, d2 = 0; |
1da177e4 | 619 | unsigned long back_max; |
e8a99053 AM |
620 | #define CFQ_RQ1_WRAP 0x01 /* request 1 wraps */ |
621 | #define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */ | |
622 | unsigned wrap = 0; /* bit mask: requests behind the disk head? */ | |
1da177e4 | 623 | |
5e705374 JA |
624 | if (rq1 == NULL || rq1 == rq2) |
625 | return rq2; | |
626 | if (rq2 == NULL) | |
627 | return rq1; | |
9c2c38a1 | 628 | |
5e705374 JA |
629 | if (rq_is_sync(rq1) && !rq_is_sync(rq2)) |
630 | return rq1; | |
631 | else if (rq_is_sync(rq2) && !rq_is_sync(rq1)) | |
632 | return rq2; | |
374f84ac JA |
633 | if (rq_is_meta(rq1) && !rq_is_meta(rq2)) |
634 | return rq1; | |
635 | else if (rq_is_meta(rq2) && !rq_is_meta(rq1)) | |
636 | return rq2; | |
1da177e4 | 637 | |
83096ebf TH |
638 | s1 = blk_rq_pos(rq1); |
639 | s2 = blk_rq_pos(rq2); | |
1da177e4 | 640 | |
1da177e4 LT |
641 | /* |
642 | * by definition, 1KiB is 2 sectors | |
643 | */ | |
644 | back_max = cfqd->cfq_back_max * 2; | |
645 | ||
646 | /* | |
647 | * Strict one way elevator _except_ in the case where we allow | |
648 | * short backward seeks which are biased as twice the cost of a | |
649 | * similar forward seek. | |
650 | */ | |
651 | if (s1 >= last) | |
652 | d1 = s1 - last; | |
653 | else if (s1 + back_max >= last) | |
654 | d1 = (last - s1) * cfqd->cfq_back_penalty; | |
655 | else | |
e8a99053 | 656 | wrap |= CFQ_RQ1_WRAP; |
1da177e4 LT |
657 | |
658 | if (s2 >= last) | |
659 | d2 = s2 - last; | |
660 | else if (s2 + back_max >= last) | |
661 | d2 = (last - s2) * cfqd->cfq_back_penalty; | |
662 | else | |
e8a99053 | 663 | wrap |= CFQ_RQ2_WRAP; |
1da177e4 LT |
664 | |
665 | /* Found required data */ | |
e8a99053 AM |
666 | |
667 | /* | |
668 | * By doing switch() on the bit mask "wrap" we avoid having to | |
669 | * check two variables for all permutations: --> faster! | |
670 | */ | |
671 | switch (wrap) { | |
5e705374 | 672 | case 0: /* common case for CFQ: rq1 and rq2 not wrapped */ |
e8a99053 | 673 | if (d1 < d2) |
5e705374 | 674 | return rq1; |
e8a99053 | 675 | else if (d2 < d1) |
5e705374 | 676 | return rq2; |
e8a99053 AM |
677 | else { |
678 | if (s1 >= s2) | |
5e705374 | 679 | return rq1; |
e8a99053 | 680 | else |
5e705374 | 681 | return rq2; |
e8a99053 | 682 | } |
1da177e4 | 683 | |
e8a99053 | 684 | case CFQ_RQ2_WRAP: |
5e705374 | 685 | return rq1; |
e8a99053 | 686 | case CFQ_RQ1_WRAP: |
5e705374 JA |
687 | return rq2; |
688 | case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both rqs wrapped */ | |
e8a99053 AM |
689 | default: |
690 | /* | |
691 | * Since both rqs are wrapped, | |
692 | * start with the one that's further behind head | |
693 | * (--> only *one* back seek required), | |
694 | * since back seek takes more time than forward. | |
695 | */ | |
696 | if (s1 <= s2) | |
5e705374 | 697 | return rq1; |
1da177e4 | 698 | else |
5e705374 | 699 | return rq2; |
1da177e4 LT |
700 | } |
701 | } | |
702 | ||
498d3aa2 JA |
703 | /* |
704 | * The below is leftmost cache rbtree addon | |
705 | */ | |
0871714e | 706 | static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root) |
cc09e299 | 707 | { |
615f0259 VG |
708 | /* Service tree is empty */ |
709 | if (!root->count) | |
710 | return NULL; | |
711 | ||
cc09e299 JA |
712 | if (!root->left) |
713 | root->left = rb_first(&root->rb); | |
714 | ||
0871714e JA |
715 | if (root->left) |
716 | return rb_entry(root->left, struct cfq_queue, rb_node); | |
717 | ||
718 | return NULL; | |
cc09e299 JA |
719 | } |
720 | ||
1fa8f6d6 VG |
721 | static struct cfq_group *cfq_rb_first_group(struct cfq_rb_root *root) |
722 | { | |
723 | if (!root->left) | |
724 | root->left = rb_first(&root->rb); | |
725 | ||
726 | if (root->left) | |
727 | return rb_entry_cfqg(root->left); | |
728 | ||
729 | return NULL; | |
730 | } | |
731 | ||
a36e71f9 JA |
732 | static void rb_erase_init(struct rb_node *n, struct rb_root *root) |
733 | { | |
734 | rb_erase(n, root); | |
735 | RB_CLEAR_NODE(n); | |
736 | } | |
737 | ||
cc09e299 JA |
738 | static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root) |
739 | { | |
740 | if (root->left == n) | |
741 | root->left = NULL; | |
a36e71f9 | 742 | rb_erase_init(n, &root->rb); |
aa6f6a3d | 743 | --root->count; |
cc09e299 JA |
744 | } |
745 | ||
1da177e4 LT |
746 | /* |
747 | * would be nice to take fifo expire time into account as well | |
748 | */ | |
5e705374 JA |
749 | static struct request * |
750 | cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
751 | struct request *last) | |
1da177e4 | 752 | { |
21183b07 JA |
753 | struct rb_node *rbnext = rb_next(&last->rb_node); |
754 | struct rb_node *rbprev = rb_prev(&last->rb_node); | |
5e705374 | 755 | struct request *next = NULL, *prev = NULL; |
1da177e4 | 756 | |
21183b07 | 757 | BUG_ON(RB_EMPTY_NODE(&last->rb_node)); |
1da177e4 LT |
758 | |
759 | if (rbprev) | |
5e705374 | 760 | prev = rb_entry_rq(rbprev); |
1da177e4 | 761 | |
21183b07 | 762 | if (rbnext) |
5e705374 | 763 | next = rb_entry_rq(rbnext); |
21183b07 JA |
764 | else { |
765 | rbnext = rb_first(&cfqq->sort_list); | |
766 | if (rbnext && rbnext != &last->rb_node) | |
5e705374 | 767 | next = rb_entry_rq(rbnext); |
21183b07 | 768 | } |
1da177e4 | 769 | |
cf7c25cf | 770 | return cfq_choose_req(cfqd, next, prev, blk_rq_pos(last)); |
1da177e4 LT |
771 | } |
772 | ||
d9e7620e JA |
773 | static unsigned long cfq_slice_offset(struct cfq_data *cfqd, |
774 | struct cfq_queue *cfqq) | |
1da177e4 | 775 | { |
d9e7620e JA |
776 | /* |
777 | * just an approximation, should be ok. | |
778 | */ | |
cdb16e8f | 779 | return (cfqq->cfqg->nr_cfqq - 1) * (cfq_prio_slice(cfqd, 1, 0) - |
464191c6 | 780 | cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio)); |
d9e7620e JA |
781 | } |
782 | ||
1fa8f6d6 VG |
783 | static inline s64 |
784 | cfqg_key(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
785 | { | |
786 | return cfqg->vdisktime - st->min_vdisktime; | |
787 | } | |
788 | ||
789 | static void | |
790 | __cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
791 | { | |
792 | struct rb_node **node = &st->rb.rb_node; | |
793 | struct rb_node *parent = NULL; | |
794 | struct cfq_group *__cfqg; | |
795 | s64 key = cfqg_key(st, cfqg); | |
796 | int left = 1; | |
797 | ||
798 | while (*node != NULL) { | |
799 | parent = *node; | |
800 | __cfqg = rb_entry_cfqg(parent); | |
801 | ||
802 | if (key < cfqg_key(st, __cfqg)) | |
803 | node = &parent->rb_left; | |
804 | else { | |
805 | node = &parent->rb_right; | |
806 | left = 0; | |
807 | } | |
808 | } | |
809 | ||
810 | if (left) | |
811 | st->left = &cfqg->rb_node; | |
812 | ||
813 | rb_link_node(&cfqg->rb_node, parent, node); | |
814 | rb_insert_color(&cfqg->rb_node, &st->rb); | |
815 | } | |
816 | ||
817 | static void | |
818 | cfq_group_service_tree_add(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
819 | { | |
820 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
821 | struct cfq_group *__cfqg; | |
822 | struct rb_node *n; | |
823 | ||
824 | cfqg->nr_cfqq++; | |
825 | if (cfqg->on_st) | |
826 | return; | |
827 | ||
828 | /* | |
829 | * Currently put the group at the end. Later implement something | |
830 | * so that groups get lesser vtime based on their weights, so that | |
831 | * if group does not loose all if it was not continously backlogged. | |
832 | */ | |
833 | n = rb_last(&st->rb); | |
834 | if (n) { | |
835 | __cfqg = rb_entry_cfqg(n); | |
836 | cfqg->vdisktime = __cfqg->vdisktime + CFQ_IDLE_DELAY; | |
837 | } else | |
838 | cfqg->vdisktime = st->min_vdisktime; | |
839 | ||
840 | __cfq_group_service_tree_add(st, cfqg); | |
841 | cfqg->on_st = true; | |
58ff82f3 | 842 | st->total_weight += cfqg->weight; |
1fa8f6d6 VG |
843 | } |
844 | ||
845 | static void | |
846 | cfq_group_service_tree_del(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
847 | { | |
848 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
849 | ||
25bc6b07 VG |
850 | if (st->active == &cfqg->rb_node) |
851 | st->active = NULL; | |
852 | ||
1fa8f6d6 VG |
853 | BUG_ON(cfqg->nr_cfqq < 1); |
854 | cfqg->nr_cfqq--; | |
25bc6b07 | 855 | |
1fa8f6d6 VG |
856 | /* If there are other cfq queues under this group, don't delete it */ |
857 | if (cfqg->nr_cfqq) | |
858 | return; | |
859 | ||
2868ef7b | 860 | cfq_log_cfqg(cfqd, cfqg, "del_from_rr group"); |
1fa8f6d6 | 861 | cfqg->on_st = false; |
58ff82f3 | 862 | st->total_weight -= cfqg->weight; |
1fa8f6d6 VG |
863 | if (!RB_EMPTY_NODE(&cfqg->rb_node)) |
864 | cfq_rb_erase(&cfqg->rb_node, st); | |
dae739eb | 865 | cfqg->saved_workload_slice = 0; |
22084190 | 866 | blkiocg_update_blkio_group_dequeue_stats(&cfqg->blkg, 1); |
dae739eb VG |
867 | } |
868 | ||
869 | static inline unsigned int cfq_cfqq_slice_usage(struct cfq_queue *cfqq) | |
870 | { | |
f75edf2d | 871 | unsigned int slice_used; |
dae739eb VG |
872 | |
873 | /* | |
874 | * Queue got expired before even a single request completed or | |
875 | * got expired immediately after first request completion. | |
876 | */ | |
877 | if (!cfqq->slice_start || cfqq->slice_start == jiffies) { | |
878 | /* | |
879 | * Also charge the seek time incurred to the group, otherwise | |
880 | * if there are mutiple queues in the group, each can dispatch | |
881 | * a single request on seeky media and cause lots of seek time | |
882 | * and group will never know it. | |
883 | */ | |
884 | slice_used = max_t(unsigned, (jiffies - cfqq->dispatch_start), | |
885 | 1); | |
886 | } else { | |
887 | slice_used = jiffies - cfqq->slice_start; | |
f75edf2d VG |
888 | if (slice_used > cfqq->allocated_slice) |
889 | slice_used = cfqq->allocated_slice; | |
dae739eb VG |
890 | } |
891 | ||
22084190 VG |
892 | cfq_log_cfqq(cfqq->cfqd, cfqq, "sl_used=%u sect=%lu", slice_used, |
893 | cfqq->nr_sectors); | |
dae739eb VG |
894 | return slice_used; |
895 | } | |
896 | ||
897 | static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg, | |
898 | struct cfq_queue *cfqq) | |
899 | { | |
900 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
f26bd1f0 VG |
901 | unsigned int used_sl, charge_sl; |
902 | int nr_sync = cfqg->nr_cfqq - cfqg_busy_async_queues(cfqd, cfqg) | |
903 | - cfqg->service_tree_idle.count; | |
904 | ||
905 | BUG_ON(nr_sync < 0); | |
906 | used_sl = charge_sl = cfq_cfqq_slice_usage(cfqq); | |
dae739eb | 907 | |
f26bd1f0 VG |
908 | if (!cfq_cfqq_sync(cfqq) && !nr_sync) |
909 | charge_sl = cfqq->allocated_slice; | |
dae739eb VG |
910 | |
911 | /* Can't update vdisktime while group is on service tree */ | |
912 | cfq_rb_erase(&cfqg->rb_node, st); | |
f26bd1f0 | 913 | cfqg->vdisktime += cfq_scale_slice(charge_sl, cfqg); |
dae739eb VG |
914 | __cfq_group_service_tree_add(st, cfqg); |
915 | ||
916 | /* This group is being expired. Save the context */ | |
917 | if (time_after(cfqd->workload_expires, jiffies)) { | |
918 | cfqg->saved_workload_slice = cfqd->workload_expires | |
919 | - jiffies; | |
920 | cfqg->saved_workload = cfqd->serving_type; | |
921 | cfqg->saved_serving_prio = cfqd->serving_prio; | |
922 | } else | |
923 | cfqg->saved_workload_slice = 0; | |
2868ef7b VG |
924 | |
925 | cfq_log_cfqg(cfqd, cfqg, "served: vt=%llu min_vt=%llu", cfqg->vdisktime, | |
926 | st->min_vdisktime); | |
22084190 VG |
927 | blkiocg_update_blkio_group_stats(&cfqg->blkg, used_sl, |
928 | cfqq->nr_sectors); | |
1fa8f6d6 VG |
929 | } |
930 | ||
25fb5169 VG |
931 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
932 | static inline struct cfq_group *cfqg_of_blkg(struct blkio_group *blkg) | |
933 | { | |
934 | if (blkg) | |
935 | return container_of(blkg, struct cfq_group, blkg); | |
936 | return NULL; | |
937 | } | |
938 | ||
f8d461d6 VG |
939 | void |
940 | cfq_update_blkio_group_weight(struct blkio_group *blkg, unsigned int weight) | |
941 | { | |
942 | cfqg_of_blkg(blkg)->weight = weight; | |
943 | } | |
944 | ||
25fb5169 VG |
945 | static struct cfq_group * |
946 | cfq_find_alloc_cfqg(struct cfq_data *cfqd, struct cgroup *cgroup, int create) | |
947 | { | |
948 | struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup); | |
949 | struct cfq_group *cfqg = NULL; | |
950 | void *key = cfqd; | |
951 | int i, j; | |
952 | struct cfq_rb_root *st; | |
22084190 VG |
953 | struct backing_dev_info *bdi = &cfqd->queue->backing_dev_info; |
954 | unsigned int major, minor; | |
25fb5169 VG |
955 | |
956 | /* Do we need to take this reference */ | |
9d6a986c | 957 | if (!blkiocg_css_tryget(blkcg)) |
25fb5169 VG |
958 | return NULL;; |
959 | ||
960 | cfqg = cfqg_of_blkg(blkiocg_lookup_group(blkcg, key)); | |
961 | if (cfqg || !create) | |
962 | goto done; | |
963 | ||
964 | cfqg = kzalloc_node(sizeof(*cfqg), GFP_ATOMIC, cfqd->queue->node); | |
965 | if (!cfqg) | |
966 | goto done; | |
967 | ||
968 | cfqg->weight = blkcg->weight; | |
969 | for_each_cfqg_st(cfqg, i, j, st) | |
970 | *st = CFQ_RB_ROOT; | |
971 | RB_CLEAR_NODE(&cfqg->rb_node); | |
972 | ||
b1c35769 VG |
973 | /* |
974 | * Take the initial reference that will be released on destroy | |
975 | * This can be thought of a joint reference by cgroup and | |
976 | * elevator which will be dropped by either elevator exit | |
977 | * or cgroup deletion path depending on who is exiting first. | |
978 | */ | |
979 | atomic_set(&cfqg->ref, 1); | |
980 | ||
25fb5169 | 981 | /* Add group onto cgroup list */ |
22084190 VG |
982 | sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor); |
983 | blkiocg_add_blkio_group(blkcg, &cfqg->blkg, (void *)cfqd, | |
984 | MKDEV(major, minor)); | |
25fb5169 VG |
985 | |
986 | /* Add group on cfqd list */ | |
987 | hlist_add_head(&cfqg->cfqd_node, &cfqd->cfqg_list); | |
988 | ||
989 | done: | |
9d6a986c | 990 | blkiocg_css_put(blkcg); |
25fb5169 VG |
991 | return cfqg; |
992 | } | |
993 | ||
994 | /* | |
995 | * Search for the cfq group current task belongs to. If create = 1, then also | |
996 | * create the cfq group if it does not exist. request_queue lock must be held. | |
997 | */ | |
998 | static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd, int create) | |
999 | { | |
1000 | struct cgroup *cgroup; | |
1001 | struct cfq_group *cfqg = NULL; | |
1002 | ||
1003 | rcu_read_lock(); | |
1004 | cgroup = task_cgroup(current, blkio_subsys_id); | |
1005 | cfqg = cfq_find_alloc_cfqg(cfqd, cgroup, create); | |
1006 | if (!cfqg && create) | |
1007 | cfqg = &cfqd->root_group; | |
1008 | rcu_read_unlock(); | |
1009 | return cfqg; | |
1010 | } | |
1011 | ||
1012 | static void cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) | |
1013 | { | |
1014 | /* Currently, all async queues are mapped to root group */ | |
1015 | if (!cfq_cfqq_sync(cfqq)) | |
1016 | cfqg = &cfqq->cfqd->root_group; | |
1017 | ||
1018 | cfqq->cfqg = cfqg; | |
b1c35769 VG |
1019 | /* cfqq reference on cfqg */ |
1020 | atomic_inc(&cfqq->cfqg->ref); | |
1021 | } | |
1022 | ||
1023 | static void cfq_put_cfqg(struct cfq_group *cfqg) | |
1024 | { | |
1025 | struct cfq_rb_root *st; | |
1026 | int i, j; | |
1027 | ||
1028 | BUG_ON(atomic_read(&cfqg->ref) <= 0); | |
1029 | if (!atomic_dec_and_test(&cfqg->ref)) | |
1030 | return; | |
1031 | for_each_cfqg_st(cfqg, i, j, st) | |
1032 | BUG_ON(!RB_EMPTY_ROOT(&st->rb) || st->active != NULL); | |
1033 | kfree(cfqg); | |
1034 | } | |
1035 | ||
1036 | static void cfq_destroy_cfqg(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
1037 | { | |
1038 | /* Something wrong if we are trying to remove same group twice */ | |
1039 | BUG_ON(hlist_unhashed(&cfqg->cfqd_node)); | |
1040 | ||
1041 | hlist_del_init(&cfqg->cfqd_node); | |
1042 | ||
1043 | /* | |
1044 | * Put the reference taken at the time of creation so that when all | |
1045 | * queues are gone, group can be destroyed. | |
1046 | */ | |
1047 | cfq_put_cfqg(cfqg); | |
1048 | } | |
1049 | ||
1050 | static void cfq_release_cfq_groups(struct cfq_data *cfqd) | |
1051 | { | |
1052 | struct hlist_node *pos, *n; | |
1053 | struct cfq_group *cfqg; | |
1054 | ||
1055 | hlist_for_each_entry_safe(cfqg, pos, n, &cfqd->cfqg_list, cfqd_node) { | |
1056 | /* | |
1057 | * If cgroup removal path got to blk_group first and removed | |
1058 | * it from cgroup list, then it will take care of destroying | |
1059 | * cfqg also. | |
1060 | */ | |
1061 | if (!blkiocg_del_blkio_group(&cfqg->blkg)) | |
1062 | cfq_destroy_cfqg(cfqd, cfqg); | |
1063 | } | |
25fb5169 | 1064 | } |
b1c35769 VG |
1065 | |
1066 | /* | |
1067 | * Blk cgroup controller notification saying that blkio_group object is being | |
1068 | * delinked as associated cgroup object is going away. That also means that | |
1069 | * no new IO will come in this group. So get rid of this group as soon as | |
1070 | * any pending IO in the group is finished. | |
1071 | * | |
1072 | * This function is called under rcu_read_lock(). key is the rcu protected | |
1073 | * pointer. That means "key" is a valid cfq_data pointer as long as we are rcu | |
1074 | * read lock. | |
1075 | * | |
1076 | * "key" was fetched from blkio_group under blkio_cgroup->lock. That means | |
1077 | * it should not be NULL as even if elevator was exiting, cgroup deltion | |
1078 | * path got to it first. | |
1079 | */ | |
1080 | void cfq_unlink_blkio_group(void *key, struct blkio_group *blkg) | |
1081 | { | |
1082 | unsigned long flags; | |
1083 | struct cfq_data *cfqd = key; | |
1084 | ||
1085 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
1086 | cfq_destroy_cfqg(cfqd, cfqg_of_blkg(blkg)); | |
1087 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
1088 | } | |
1089 | ||
25fb5169 VG |
1090 | #else /* GROUP_IOSCHED */ |
1091 | static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd, int create) | |
1092 | { | |
1093 | return &cfqd->root_group; | |
1094 | } | |
1095 | static inline void | |
1096 | cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) { | |
1097 | cfqq->cfqg = cfqg; | |
1098 | } | |
1099 | ||
b1c35769 VG |
1100 | static void cfq_release_cfq_groups(struct cfq_data *cfqd) {} |
1101 | static inline void cfq_put_cfqg(struct cfq_group *cfqg) {} | |
1102 | ||
25fb5169 VG |
1103 | #endif /* GROUP_IOSCHED */ |
1104 | ||
498d3aa2 | 1105 | /* |
c0324a02 | 1106 | * The cfqd->service_trees holds all pending cfq_queue's that have |
498d3aa2 JA |
1107 | * requests waiting to be processed. It is sorted in the order that |
1108 | * we will service the queues. | |
1109 | */ | |
a36e71f9 | 1110 | static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
a6151c3a | 1111 | bool add_front) |
d9e7620e | 1112 | { |
0871714e JA |
1113 | struct rb_node **p, *parent; |
1114 | struct cfq_queue *__cfqq; | |
d9e7620e | 1115 | unsigned long rb_key; |
c0324a02 | 1116 | struct cfq_rb_root *service_tree; |
498d3aa2 | 1117 | int left; |
dae739eb | 1118 | int new_cfqq = 1; |
ae30c286 VG |
1119 | int group_changed = 0; |
1120 | ||
1121 | #ifdef CONFIG_CFQ_GROUP_IOSCHED | |
1122 | if (!cfqd->cfq_group_isolation | |
1123 | && cfqq_type(cfqq) == SYNC_NOIDLE_WORKLOAD | |
1124 | && cfqq->cfqg && cfqq->cfqg != &cfqd->root_group) { | |
1125 | /* Move this cfq to root group */ | |
1126 | cfq_log_cfqq(cfqd, cfqq, "moving to root group"); | |
1127 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) | |
1128 | cfq_group_service_tree_del(cfqd, cfqq->cfqg); | |
1129 | cfqq->orig_cfqg = cfqq->cfqg; | |
1130 | cfqq->cfqg = &cfqd->root_group; | |
1131 | atomic_inc(&cfqd->root_group.ref); | |
1132 | group_changed = 1; | |
1133 | } else if (!cfqd->cfq_group_isolation | |
1134 | && cfqq_type(cfqq) == SYNC_WORKLOAD && cfqq->orig_cfqg) { | |
1135 | /* cfqq is sequential now needs to go to its original group */ | |
1136 | BUG_ON(cfqq->cfqg != &cfqd->root_group); | |
1137 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) | |
1138 | cfq_group_service_tree_del(cfqd, cfqq->cfqg); | |
1139 | cfq_put_cfqg(cfqq->cfqg); | |
1140 | cfqq->cfqg = cfqq->orig_cfqg; | |
1141 | cfqq->orig_cfqg = NULL; | |
1142 | group_changed = 1; | |
1143 | cfq_log_cfqq(cfqd, cfqq, "moved to origin group"); | |
1144 | } | |
1145 | #endif | |
d9e7620e | 1146 | |
cdb16e8f | 1147 | service_tree = service_tree_for(cfqq->cfqg, cfqq_prio(cfqq), |
65b32a57 | 1148 | cfqq_type(cfqq)); |
0871714e JA |
1149 | if (cfq_class_idle(cfqq)) { |
1150 | rb_key = CFQ_IDLE_DELAY; | |
aa6f6a3d | 1151 | parent = rb_last(&service_tree->rb); |
0871714e JA |
1152 | if (parent && parent != &cfqq->rb_node) { |
1153 | __cfqq = rb_entry(parent, struct cfq_queue, rb_node); | |
1154 | rb_key += __cfqq->rb_key; | |
1155 | } else | |
1156 | rb_key += jiffies; | |
1157 | } else if (!add_front) { | |
b9c8946b JA |
1158 | /* |
1159 | * Get our rb key offset. Subtract any residual slice | |
1160 | * value carried from last service. A negative resid | |
1161 | * count indicates slice overrun, and this should position | |
1162 | * the next service time further away in the tree. | |
1163 | */ | |
edd75ffd | 1164 | rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies; |
b9c8946b | 1165 | rb_key -= cfqq->slice_resid; |
edd75ffd | 1166 | cfqq->slice_resid = 0; |
48e025e6 CZ |
1167 | } else { |
1168 | rb_key = -HZ; | |
aa6f6a3d | 1169 | __cfqq = cfq_rb_first(service_tree); |
48e025e6 CZ |
1170 | rb_key += __cfqq ? __cfqq->rb_key : jiffies; |
1171 | } | |
1da177e4 | 1172 | |
d9e7620e | 1173 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) { |
dae739eb | 1174 | new_cfqq = 0; |
99f9628a | 1175 | /* |
d9e7620e | 1176 | * same position, nothing more to do |
99f9628a | 1177 | */ |
c0324a02 CZ |
1178 | if (rb_key == cfqq->rb_key && |
1179 | cfqq->service_tree == service_tree) | |
d9e7620e | 1180 | return; |
1da177e4 | 1181 | |
aa6f6a3d CZ |
1182 | cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree); |
1183 | cfqq->service_tree = NULL; | |
1da177e4 | 1184 | } |
d9e7620e | 1185 | |
498d3aa2 | 1186 | left = 1; |
0871714e | 1187 | parent = NULL; |
aa6f6a3d CZ |
1188 | cfqq->service_tree = service_tree; |
1189 | p = &service_tree->rb.rb_node; | |
d9e7620e | 1190 | while (*p) { |
67060e37 | 1191 | struct rb_node **n; |
cc09e299 | 1192 | |
d9e7620e JA |
1193 | parent = *p; |
1194 | __cfqq = rb_entry(parent, struct cfq_queue, rb_node); | |
1195 | ||
0c534e0a | 1196 | /* |
c0324a02 | 1197 | * sort by key, that represents service time. |
0c534e0a | 1198 | */ |
c0324a02 | 1199 | if (time_before(rb_key, __cfqq->rb_key)) |
67060e37 | 1200 | n = &(*p)->rb_left; |
c0324a02 | 1201 | else { |
67060e37 | 1202 | n = &(*p)->rb_right; |
cc09e299 | 1203 | left = 0; |
c0324a02 | 1204 | } |
67060e37 JA |
1205 | |
1206 | p = n; | |
d9e7620e JA |
1207 | } |
1208 | ||
cc09e299 | 1209 | if (left) |
aa6f6a3d | 1210 | service_tree->left = &cfqq->rb_node; |
cc09e299 | 1211 | |
d9e7620e JA |
1212 | cfqq->rb_key = rb_key; |
1213 | rb_link_node(&cfqq->rb_node, parent, p); | |
aa6f6a3d CZ |
1214 | rb_insert_color(&cfqq->rb_node, &service_tree->rb); |
1215 | service_tree->count++; | |
ae30c286 | 1216 | if ((add_front || !new_cfqq) && !group_changed) |
dae739eb | 1217 | return; |
1fa8f6d6 | 1218 | cfq_group_service_tree_add(cfqd, cfqq->cfqg); |
1da177e4 LT |
1219 | } |
1220 | ||
a36e71f9 | 1221 | static struct cfq_queue * |
f2d1f0ae JA |
1222 | cfq_prio_tree_lookup(struct cfq_data *cfqd, struct rb_root *root, |
1223 | sector_t sector, struct rb_node **ret_parent, | |
1224 | struct rb_node ***rb_link) | |
a36e71f9 | 1225 | { |
a36e71f9 JA |
1226 | struct rb_node **p, *parent; |
1227 | struct cfq_queue *cfqq = NULL; | |
1228 | ||
1229 | parent = NULL; | |
1230 | p = &root->rb_node; | |
1231 | while (*p) { | |
1232 | struct rb_node **n; | |
1233 | ||
1234 | parent = *p; | |
1235 | cfqq = rb_entry(parent, struct cfq_queue, p_node); | |
1236 | ||
1237 | /* | |
1238 | * Sort strictly based on sector. Smallest to the left, | |
1239 | * largest to the right. | |
1240 | */ | |
2e46e8b2 | 1241 | if (sector > blk_rq_pos(cfqq->next_rq)) |
a36e71f9 | 1242 | n = &(*p)->rb_right; |
2e46e8b2 | 1243 | else if (sector < blk_rq_pos(cfqq->next_rq)) |
a36e71f9 JA |
1244 | n = &(*p)->rb_left; |
1245 | else | |
1246 | break; | |
1247 | p = n; | |
3ac6c9f8 | 1248 | cfqq = NULL; |
a36e71f9 JA |
1249 | } |
1250 | ||
1251 | *ret_parent = parent; | |
1252 | if (rb_link) | |
1253 | *rb_link = p; | |
3ac6c9f8 | 1254 | return cfqq; |
a36e71f9 JA |
1255 | } |
1256 | ||
1257 | static void cfq_prio_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1258 | { | |
a36e71f9 JA |
1259 | struct rb_node **p, *parent; |
1260 | struct cfq_queue *__cfqq; | |
1261 | ||
f2d1f0ae JA |
1262 | if (cfqq->p_root) { |
1263 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
1264 | cfqq->p_root = NULL; | |
1265 | } | |
a36e71f9 JA |
1266 | |
1267 | if (cfq_class_idle(cfqq)) | |
1268 | return; | |
1269 | if (!cfqq->next_rq) | |
1270 | return; | |
1271 | ||
f2d1f0ae | 1272 | cfqq->p_root = &cfqd->prio_trees[cfqq->org_ioprio]; |
2e46e8b2 TH |
1273 | __cfqq = cfq_prio_tree_lookup(cfqd, cfqq->p_root, |
1274 | blk_rq_pos(cfqq->next_rq), &parent, &p); | |
3ac6c9f8 JA |
1275 | if (!__cfqq) { |
1276 | rb_link_node(&cfqq->p_node, parent, p); | |
f2d1f0ae JA |
1277 | rb_insert_color(&cfqq->p_node, cfqq->p_root); |
1278 | } else | |
1279 | cfqq->p_root = NULL; | |
a36e71f9 JA |
1280 | } |
1281 | ||
498d3aa2 JA |
1282 | /* |
1283 | * Update cfqq's position in the service tree. | |
1284 | */ | |
edd75ffd | 1285 | static void cfq_resort_rr_list(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
6d048f53 | 1286 | { |
6d048f53 JA |
1287 | /* |
1288 | * Resorting requires the cfqq to be on the RR list already. | |
1289 | */ | |
a36e71f9 | 1290 | if (cfq_cfqq_on_rr(cfqq)) { |
edd75ffd | 1291 | cfq_service_tree_add(cfqd, cfqq, 0); |
a36e71f9 JA |
1292 | cfq_prio_tree_add(cfqd, cfqq); |
1293 | } | |
6d048f53 JA |
1294 | } |
1295 | ||
1da177e4 LT |
1296 | /* |
1297 | * add to busy list of queues for service, trying to be fair in ordering | |
22e2c507 | 1298 | * the pending list according to last request service |
1da177e4 | 1299 | */ |
febffd61 | 1300 | static void cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 1301 | { |
7b679138 | 1302 | cfq_log_cfqq(cfqd, cfqq, "add_to_rr"); |
3b18152c JA |
1303 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
1304 | cfq_mark_cfqq_on_rr(cfqq); | |
1da177e4 LT |
1305 | cfqd->busy_queues++; |
1306 | ||
edd75ffd | 1307 | cfq_resort_rr_list(cfqd, cfqq); |
1da177e4 LT |
1308 | } |
1309 | ||
498d3aa2 JA |
1310 | /* |
1311 | * Called when the cfqq no longer has requests pending, remove it from | |
1312 | * the service tree. | |
1313 | */ | |
febffd61 | 1314 | static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 1315 | { |
7b679138 | 1316 | cfq_log_cfqq(cfqd, cfqq, "del_from_rr"); |
3b18152c JA |
1317 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
1318 | cfq_clear_cfqq_on_rr(cfqq); | |
1da177e4 | 1319 | |
aa6f6a3d CZ |
1320 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) { |
1321 | cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree); | |
1322 | cfqq->service_tree = NULL; | |
1323 | } | |
f2d1f0ae JA |
1324 | if (cfqq->p_root) { |
1325 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
1326 | cfqq->p_root = NULL; | |
1327 | } | |
d9e7620e | 1328 | |
1fa8f6d6 | 1329 | cfq_group_service_tree_del(cfqd, cfqq->cfqg); |
1da177e4 LT |
1330 | BUG_ON(!cfqd->busy_queues); |
1331 | cfqd->busy_queues--; | |
1332 | } | |
1333 | ||
1334 | /* | |
1335 | * rb tree support functions | |
1336 | */ | |
febffd61 | 1337 | static void cfq_del_rq_rb(struct request *rq) |
1da177e4 | 1338 | { |
5e705374 | 1339 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
5e705374 | 1340 | const int sync = rq_is_sync(rq); |
1da177e4 | 1341 | |
b4878f24 JA |
1342 | BUG_ON(!cfqq->queued[sync]); |
1343 | cfqq->queued[sync]--; | |
1da177e4 | 1344 | |
5e705374 | 1345 | elv_rb_del(&cfqq->sort_list, rq); |
1da177e4 | 1346 | |
f04a6424 VG |
1347 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) { |
1348 | /* | |
1349 | * Queue will be deleted from service tree when we actually | |
1350 | * expire it later. Right now just remove it from prio tree | |
1351 | * as it is empty. | |
1352 | */ | |
1353 | if (cfqq->p_root) { | |
1354 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
1355 | cfqq->p_root = NULL; | |
1356 | } | |
1357 | } | |
1da177e4 LT |
1358 | } |
1359 | ||
5e705374 | 1360 | static void cfq_add_rq_rb(struct request *rq) |
1da177e4 | 1361 | { |
5e705374 | 1362 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
1da177e4 | 1363 | struct cfq_data *cfqd = cfqq->cfqd; |
a36e71f9 | 1364 | struct request *__alias, *prev; |
1da177e4 | 1365 | |
5380a101 | 1366 | cfqq->queued[rq_is_sync(rq)]++; |
1da177e4 LT |
1367 | |
1368 | /* | |
1369 | * looks a little odd, but the first insert might return an alias. | |
1370 | * if that happens, put the alias on the dispatch list | |
1371 | */ | |
21183b07 | 1372 | while ((__alias = elv_rb_add(&cfqq->sort_list, rq)) != NULL) |
5e705374 | 1373 | cfq_dispatch_insert(cfqd->queue, __alias); |
5fccbf61 JA |
1374 | |
1375 | if (!cfq_cfqq_on_rr(cfqq)) | |
1376 | cfq_add_cfqq_rr(cfqd, cfqq); | |
5044eed4 JA |
1377 | |
1378 | /* | |
1379 | * check if this request is a better next-serve candidate | |
1380 | */ | |
a36e71f9 | 1381 | prev = cfqq->next_rq; |
cf7c25cf | 1382 | cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq, cfqd->last_position); |
a36e71f9 JA |
1383 | |
1384 | /* | |
1385 | * adjust priority tree position, if ->next_rq changes | |
1386 | */ | |
1387 | if (prev != cfqq->next_rq) | |
1388 | cfq_prio_tree_add(cfqd, cfqq); | |
1389 | ||
5044eed4 | 1390 | BUG_ON(!cfqq->next_rq); |
1da177e4 LT |
1391 | } |
1392 | ||
febffd61 | 1393 | static void cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq) |
1da177e4 | 1394 | { |
5380a101 JA |
1395 | elv_rb_del(&cfqq->sort_list, rq); |
1396 | cfqq->queued[rq_is_sync(rq)]--; | |
5e705374 | 1397 | cfq_add_rq_rb(rq); |
1da177e4 LT |
1398 | } |
1399 | ||
206dc69b JA |
1400 | static struct request * |
1401 | cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio) | |
1da177e4 | 1402 | { |
206dc69b | 1403 | struct task_struct *tsk = current; |
91fac317 | 1404 | struct cfq_io_context *cic; |
206dc69b | 1405 | struct cfq_queue *cfqq; |
1da177e4 | 1406 | |
4ac845a2 | 1407 | cic = cfq_cic_lookup(cfqd, tsk->io_context); |
91fac317 VT |
1408 | if (!cic) |
1409 | return NULL; | |
1410 | ||
1411 | cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); | |
89850f7e JA |
1412 | if (cfqq) { |
1413 | sector_t sector = bio->bi_sector + bio_sectors(bio); | |
1414 | ||
21183b07 | 1415 | return elv_rb_find(&cfqq->sort_list, sector); |
89850f7e | 1416 | } |
1da177e4 | 1417 | |
1da177e4 LT |
1418 | return NULL; |
1419 | } | |
1420 | ||
165125e1 | 1421 | static void cfq_activate_request(struct request_queue *q, struct request *rq) |
1da177e4 | 1422 | { |
22e2c507 | 1423 | struct cfq_data *cfqd = q->elevator->elevator_data; |
3b18152c | 1424 | |
5ad531db | 1425 | cfqd->rq_in_driver[rq_is_sync(rq)]++; |
7b679138 | 1426 | cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "activate rq, drv=%d", |
5ad531db | 1427 | rq_in_driver(cfqd)); |
25776e35 | 1428 | |
5b93629b | 1429 | cfqd->last_position = blk_rq_pos(rq) + blk_rq_sectors(rq); |
1da177e4 LT |
1430 | } |
1431 | ||
165125e1 | 1432 | static void cfq_deactivate_request(struct request_queue *q, struct request *rq) |
1da177e4 | 1433 | { |
b4878f24 | 1434 | struct cfq_data *cfqd = q->elevator->elevator_data; |
5ad531db | 1435 | const int sync = rq_is_sync(rq); |
b4878f24 | 1436 | |
5ad531db JA |
1437 | WARN_ON(!cfqd->rq_in_driver[sync]); |
1438 | cfqd->rq_in_driver[sync]--; | |
7b679138 | 1439 | cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "deactivate rq, drv=%d", |
5ad531db | 1440 | rq_in_driver(cfqd)); |
1da177e4 LT |
1441 | } |
1442 | ||
b4878f24 | 1443 | static void cfq_remove_request(struct request *rq) |
1da177e4 | 1444 | { |
5e705374 | 1445 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
21183b07 | 1446 | |
5e705374 JA |
1447 | if (cfqq->next_rq == rq) |
1448 | cfqq->next_rq = cfq_find_next_rq(cfqq->cfqd, cfqq, rq); | |
1da177e4 | 1449 | |
b4878f24 | 1450 | list_del_init(&rq->queuelist); |
5e705374 | 1451 | cfq_del_rq_rb(rq); |
374f84ac | 1452 | |
45333d5a | 1453 | cfqq->cfqd->rq_queued--; |
374f84ac JA |
1454 | if (rq_is_meta(rq)) { |
1455 | WARN_ON(!cfqq->meta_pending); | |
1456 | cfqq->meta_pending--; | |
1457 | } | |
1da177e4 LT |
1458 | } |
1459 | ||
165125e1 JA |
1460 | static int cfq_merge(struct request_queue *q, struct request **req, |
1461 | struct bio *bio) | |
1da177e4 LT |
1462 | { |
1463 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1464 | struct request *__rq; | |
1da177e4 | 1465 | |
206dc69b | 1466 | __rq = cfq_find_rq_fmerge(cfqd, bio); |
22e2c507 | 1467 | if (__rq && elv_rq_merge_ok(__rq, bio)) { |
9817064b JA |
1468 | *req = __rq; |
1469 | return ELEVATOR_FRONT_MERGE; | |
1da177e4 LT |
1470 | } |
1471 | ||
1472 | return ELEVATOR_NO_MERGE; | |
1da177e4 LT |
1473 | } |
1474 | ||
165125e1 | 1475 | static void cfq_merged_request(struct request_queue *q, struct request *req, |
21183b07 | 1476 | int type) |
1da177e4 | 1477 | { |
21183b07 | 1478 | if (type == ELEVATOR_FRONT_MERGE) { |
5e705374 | 1479 | struct cfq_queue *cfqq = RQ_CFQQ(req); |
1da177e4 | 1480 | |
5e705374 | 1481 | cfq_reposition_rq_rb(cfqq, req); |
1da177e4 | 1482 | } |
1da177e4 LT |
1483 | } |
1484 | ||
1485 | static void | |
165125e1 | 1486 | cfq_merged_requests(struct request_queue *q, struct request *rq, |
1da177e4 LT |
1487 | struct request *next) |
1488 | { | |
cf7c25cf | 1489 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 JA |
1490 | /* |
1491 | * reposition in fifo if next is older than rq | |
1492 | */ | |
1493 | if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && | |
30996f40 | 1494 | time_before(rq_fifo_time(next), rq_fifo_time(rq))) { |
22e2c507 | 1495 | list_move(&rq->queuelist, &next->queuelist); |
30996f40 JA |
1496 | rq_set_fifo_time(rq, rq_fifo_time(next)); |
1497 | } | |
22e2c507 | 1498 | |
cf7c25cf CZ |
1499 | if (cfqq->next_rq == next) |
1500 | cfqq->next_rq = rq; | |
b4878f24 | 1501 | cfq_remove_request(next); |
22e2c507 JA |
1502 | } |
1503 | ||
165125e1 | 1504 | static int cfq_allow_merge(struct request_queue *q, struct request *rq, |
da775265 JA |
1505 | struct bio *bio) |
1506 | { | |
1507 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
91fac317 | 1508 | struct cfq_io_context *cic; |
da775265 | 1509 | struct cfq_queue *cfqq; |
da775265 JA |
1510 | |
1511 | /* | |
ec8acb69 | 1512 | * Disallow merge of a sync bio into an async request. |
da775265 | 1513 | */ |
91fac317 | 1514 | if (cfq_bio_sync(bio) && !rq_is_sync(rq)) |
a6151c3a | 1515 | return false; |
da775265 JA |
1516 | |
1517 | /* | |
719d3402 JA |
1518 | * Lookup the cfqq that this bio will be queued with. Allow |
1519 | * merge only if rq is queued there. | |
da775265 | 1520 | */ |
4ac845a2 | 1521 | cic = cfq_cic_lookup(cfqd, current->io_context); |
91fac317 | 1522 | if (!cic) |
a6151c3a | 1523 | return false; |
719d3402 | 1524 | |
91fac317 | 1525 | cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); |
a6151c3a | 1526 | return cfqq == RQ_CFQQ(rq); |
da775265 JA |
1527 | } |
1528 | ||
febffd61 JA |
1529 | static void __cfq_set_active_queue(struct cfq_data *cfqd, |
1530 | struct cfq_queue *cfqq) | |
22e2c507 JA |
1531 | { |
1532 | if (cfqq) { | |
7b679138 | 1533 | cfq_log_cfqq(cfqd, cfqq, "set_active"); |
dae739eb VG |
1534 | cfqq->slice_start = 0; |
1535 | cfqq->dispatch_start = jiffies; | |
f75edf2d | 1536 | cfqq->allocated_slice = 0; |
22e2c507 | 1537 | cfqq->slice_end = 0; |
2f5cb738 | 1538 | cfqq->slice_dispatch = 0; |
22084190 | 1539 | cfqq->nr_sectors = 0; |
2f5cb738 | 1540 | |
2f5cb738 | 1541 | cfq_clear_cfqq_wait_request(cfqq); |
b029195d | 1542 | cfq_clear_cfqq_must_dispatch(cfqq); |
3b18152c JA |
1543 | cfq_clear_cfqq_must_alloc_slice(cfqq); |
1544 | cfq_clear_cfqq_fifo_expire(cfqq); | |
44f7c160 | 1545 | cfq_mark_cfqq_slice_new(cfqq); |
2f5cb738 JA |
1546 | |
1547 | del_timer(&cfqd->idle_slice_timer); | |
22e2c507 JA |
1548 | } |
1549 | ||
1550 | cfqd->active_queue = cfqq; | |
1551 | } | |
1552 | ||
7b14e3b5 JA |
1553 | /* |
1554 | * current cfqq expired its slice (or was too idle), select new one | |
1555 | */ | |
1556 | static void | |
1557 | __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
a6151c3a | 1558 | bool timed_out) |
7b14e3b5 | 1559 | { |
7b679138 JA |
1560 | cfq_log_cfqq(cfqd, cfqq, "slice expired t=%d", timed_out); |
1561 | ||
7b14e3b5 JA |
1562 | if (cfq_cfqq_wait_request(cfqq)) |
1563 | del_timer(&cfqd->idle_slice_timer); | |
1564 | ||
7b14e3b5 | 1565 | cfq_clear_cfqq_wait_request(cfqq); |
f75edf2d | 1566 | cfq_clear_cfqq_wait_busy(cfqq); |
7b14e3b5 JA |
1567 | |
1568 | /* | |
6084cdda | 1569 | * store what was left of this slice, if the queue idled/timed out |
7b14e3b5 | 1570 | */ |
7b679138 | 1571 | if (timed_out && !cfq_cfqq_slice_new(cfqq)) { |
c5b680f3 | 1572 | cfqq->slice_resid = cfqq->slice_end - jiffies; |
7b679138 JA |
1573 | cfq_log_cfqq(cfqd, cfqq, "resid=%ld", cfqq->slice_resid); |
1574 | } | |
7b14e3b5 | 1575 | |
dae739eb VG |
1576 | cfq_group_served(cfqd, cfqq->cfqg, cfqq); |
1577 | ||
f04a6424 VG |
1578 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) |
1579 | cfq_del_cfqq_rr(cfqd, cfqq); | |
1580 | ||
edd75ffd | 1581 | cfq_resort_rr_list(cfqd, cfqq); |
7b14e3b5 JA |
1582 | |
1583 | if (cfqq == cfqd->active_queue) | |
1584 | cfqd->active_queue = NULL; | |
1585 | ||
dae739eb VG |
1586 | if (&cfqq->cfqg->rb_node == cfqd->grp_service_tree.active) |
1587 | cfqd->grp_service_tree.active = NULL; | |
1588 | ||
7b14e3b5 JA |
1589 | if (cfqd->active_cic) { |
1590 | put_io_context(cfqd->active_cic->ioc); | |
1591 | cfqd->active_cic = NULL; | |
1592 | } | |
7b14e3b5 JA |
1593 | } |
1594 | ||
a6151c3a | 1595 | static inline void cfq_slice_expired(struct cfq_data *cfqd, bool timed_out) |
7b14e3b5 JA |
1596 | { |
1597 | struct cfq_queue *cfqq = cfqd->active_queue; | |
1598 | ||
1599 | if (cfqq) | |
6084cdda | 1600 | __cfq_slice_expired(cfqd, cfqq, timed_out); |
7b14e3b5 JA |
1601 | } |
1602 | ||
498d3aa2 JA |
1603 | /* |
1604 | * Get next queue for service. Unless we have a queue preemption, | |
1605 | * we'll simply select the first cfqq in the service tree. | |
1606 | */ | |
6d048f53 | 1607 | static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd) |
22e2c507 | 1608 | { |
c0324a02 | 1609 | struct cfq_rb_root *service_tree = |
cdb16e8f | 1610 | service_tree_for(cfqd->serving_group, cfqd->serving_prio, |
65b32a57 | 1611 | cfqd->serving_type); |
d9e7620e | 1612 | |
f04a6424 VG |
1613 | if (!cfqd->rq_queued) |
1614 | return NULL; | |
1615 | ||
1fa8f6d6 VG |
1616 | /* There is nothing to dispatch */ |
1617 | if (!service_tree) | |
1618 | return NULL; | |
c0324a02 CZ |
1619 | if (RB_EMPTY_ROOT(&service_tree->rb)) |
1620 | return NULL; | |
1621 | return cfq_rb_first(service_tree); | |
6d048f53 JA |
1622 | } |
1623 | ||
f04a6424 VG |
1624 | static struct cfq_queue *cfq_get_next_queue_forced(struct cfq_data *cfqd) |
1625 | { | |
25fb5169 | 1626 | struct cfq_group *cfqg; |
f04a6424 VG |
1627 | struct cfq_queue *cfqq; |
1628 | int i, j; | |
1629 | struct cfq_rb_root *st; | |
1630 | ||
1631 | if (!cfqd->rq_queued) | |
1632 | return NULL; | |
1633 | ||
25fb5169 VG |
1634 | cfqg = cfq_get_next_cfqg(cfqd); |
1635 | if (!cfqg) | |
1636 | return NULL; | |
1637 | ||
f04a6424 VG |
1638 | for_each_cfqg_st(cfqg, i, j, st) |
1639 | if ((cfqq = cfq_rb_first(st)) != NULL) | |
1640 | return cfqq; | |
1641 | return NULL; | |
1642 | } | |
1643 | ||
498d3aa2 JA |
1644 | /* |
1645 | * Get and set a new active queue for service. | |
1646 | */ | |
a36e71f9 JA |
1647 | static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd, |
1648 | struct cfq_queue *cfqq) | |
6d048f53 | 1649 | { |
e00ef799 | 1650 | if (!cfqq) |
a36e71f9 | 1651 | cfqq = cfq_get_next_queue(cfqd); |
6d048f53 | 1652 | |
22e2c507 | 1653 | __cfq_set_active_queue(cfqd, cfqq); |
3b18152c | 1654 | return cfqq; |
22e2c507 JA |
1655 | } |
1656 | ||
d9e7620e JA |
1657 | static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd, |
1658 | struct request *rq) | |
1659 | { | |
83096ebf TH |
1660 | if (blk_rq_pos(rq) >= cfqd->last_position) |
1661 | return blk_rq_pos(rq) - cfqd->last_position; | |
d9e7620e | 1662 | else |
83096ebf | 1663 | return cfqd->last_position - blk_rq_pos(rq); |
d9e7620e JA |
1664 | } |
1665 | ||
b2c18e1e JM |
1666 | #define CFQQ_SEEK_THR 8 * 1024 |
1667 | #define CFQQ_SEEKY(cfqq) ((cfqq)->seek_mean > CFQQ_SEEK_THR) | |
04dc6e71 | 1668 | |
b2c18e1e | 1669 | static inline int cfq_rq_close(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
2f7a2d89 | 1670 | struct request *rq, bool for_preempt) |
6d048f53 | 1671 | { |
b2c18e1e | 1672 | sector_t sdist = cfqq->seek_mean; |
6d048f53 | 1673 | |
b2c18e1e JM |
1674 | if (!sample_valid(cfqq->seek_samples)) |
1675 | sdist = CFQQ_SEEK_THR; | |
6d048f53 | 1676 | |
2f7a2d89 SL |
1677 | /* if seek_mean is big, using it as close criteria is meaningless */ |
1678 | if (sdist > CFQQ_SEEK_THR && !for_preempt) | |
1679 | sdist = CFQQ_SEEK_THR; | |
1680 | ||
04dc6e71 | 1681 | return cfq_dist_from_last(cfqd, rq) <= sdist; |
6d048f53 JA |
1682 | } |
1683 | ||
a36e71f9 JA |
1684 | static struct cfq_queue *cfqq_close(struct cfq_data *cfqd, |
1685 | struct cfq_queue *cur_cfqq) | |
1686 | { | |
f2d1f0ae | 1687 | struct rb_root *root = &cfqd->prio_trees[cur_cfqq->org_ioprio]; |
a36e71f9 JA |
1688 | struct rb_node *parent, *node; |
1689 | struct cfq_queue *__cfqq; | |
1690 | sector_t sector = cfqd->last_position; | |
1691 | ||
1692 | if (RB_EMPTY_ROOT(root)) | |
1693 | return NULL; | |
1694 | ||
1695 | /* | |
1696 | * First, if we find a request starting at the end of the last | |
1697 | * request, choose it. | |
1698 | */ | |
f2d1f0ae | 1699 | __cfqq = cfq_prio_tree_lookup(cfqd, root, sector, &parent, NULL); |
a36e71f9 JA |
1700 | if (__cfqq) |
1701 | return __cfqq; | |
1702 | ||
1703 | /* | |
1704 | * If the exact sector wasn't found, the parent of the NULL leaf | |
1705 | * will contain the closest sector. | |
1706 | */ | |
1707 | __cfqq = rb_entry(parent, struct cfq_queue, p_node); | |
2f7a2d89 | 1708 | if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq, false)) |
a36e71f9 JA |
1709 | return __cfqq; |
1710 | ||
2e46e8b2 | 1711 | if (blk_rq_pos(__cfqq->next_rq) < sector) |
a36e71f9 JA |
1712 | node = rb_next(&__cfqq->p_node); |
1713 | else | |
1714 | node = rb_prev(&__cfqq->p_node); | |
1715 | if (!node) | |
1716 | return NULL; | |
1717 | ||
1718 | __cfqq = rb_entry(node, struct cfq_queue, p_node); | |
2f7a2d89 | 1719 | if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq, false)) |
a36e71f9 JA |
1720 | return __cfqq; |
1721 | ||
1722 | return NULL; | |
1723 | } | |
1724 | ||
1725 | /* | |
1726 | * cfqd - obvious | |
1727 | * cur_cfqq - passed in so that we don't decide that the current queue is | |
1728 | * closely cooperating with itself. | |
1729 | * | |
1730 | * So, basically we're assuming that that cur_cfqq has dispatched at least | |
1731 | * one request, and that cfqd->last_position reflects a position on the disk | |
1732 | * associated with the I/O issued by cur_cfqq. I'm not sure this is a valid | |
1733 | * assumption. | |
1734 | */ | |
1735 | static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd, | |
b3b6d040 | 1736 | struct cfq_queue *cur_cfqq) |
6d048f53 | 1737 | { |
a36e71f9 JA |
1738 | struct cfq_queue *cfqq; |
1739 | ||
e6c5bc73 JM |
1740 | if (!cfq_cfqq_sync(cur_cfqq)) |
1741 | return NULL; | |
1742 | if (CFQQ_SEEKY(cur_cfqq)) | |
1743 | return NULL; | |
1744 | ||
b9d8f4c7 GJ |
1745 | /* |
1746 | * Don't search priority tree if it's the only queue in the group. | |
1747 | */ | |
1748 | if (cur_cfqq->cfqg->nr_cfqq == 1) | |
1749 | return NULL; | |
1750 | ||
6d048f53 | 1751 | /* |
d9e7620e JA |
1752 | * We should notice if some of the queues are cooperating, eg |
1753 | * working closely on the same area of the disk. In that case, | |
1754 | * we can group them together and don't waste time idling. | |
6d048f53 | 1755 | */ |
a36e71f9 JA |
1756 | cfqq = cfqq_close(cfqd, cur_cfqq); |
1757 | if (!cfqq) | |
1758 | return NULL; | |
1759 | ||
8682e1f1 VG |
1760 | /* If new queue belongs to different cfq_group, don't choose it */ |
1761 | if (cur_cfqq->cfqg != cfqq->cfqg) | |
1762 | return NULL; | |
1763 | ||
df5fe3e8 JM |
1764 | /* |
1765 | * It only makes sense to merge sync queues. | |
1766 | */ | |
1767 | if (!cfq_cfqq_sync(cfqq)) | |
1768 | return NULL; | |
e6c5bc73 JM |
1769 | if (CFQQ_SEEKY(cfqq)) |
1770 | return NULL; | |
df5fe3e8 | 1771 | |
c0324a02 CZ |
1772 | /* |
1773 | * Do not merge queues of different priority classes | |
1774 | */ | |
1775 | if (cfq_class_rt(cfqq) != cfq_class_rt(cur_cfqq)) | |
1776 | return NULL; | |
1777 | ||
a36e71f9 | 1778 | return cfqq; |
6d048f53 JA |
1779 | } |
1780 | ||
a6d44e98 CZ |
1781 | /* |
1782 | * Determine whether we should enforce idle window for this queue. | |
1783 | */ | |
1784 | ||
1785 | static bool cfq_should_idle(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1786 | { | |
1787 | enum wl_prio_t prio = cfqq_prio(cfqq); | |
718eee05 | 1788 | struct cfq_rb_root *service_tree = cfqq->service_tree; |
a6d44e98 | 1789 | |
f04a6424 VG |
1790 | BUG_ON(!service_tree); |
1791 | BUG_ON(!service_tree->count); | |
1792 | ||
a6d44e98 CZ |
1793 | /* We never do for idle class queues. */ |
1794 | if (prio == IDLE_WORKLOAD) | |
1795 | return false; | |
1796 | ||
1797 | /* We do for queues that were marked with idle window flag. */ | |
3c764b7a SL |
1798 | if (cfq_cfqq_idle_window(cfqq) && |
1799 | !(blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag)) | |
a6d44e98 CZ |
1800 | return true; |
1801 | ||
1802 | /* | |
1803 | * Otherwise, we do only if they are the last ones | |
1804 | * in their service tree. | |
1805 | */ | |
f04a6424 | 1806 | return service_tree->count == 1; |
a6d44e98 CZ |
1807 | } |
1808 | ||
6d048f53 | 1809 | static void cfq_arm_slice_timer(struct cfq_data *cfqd) |
22e2c507 | 1810 | { |
1792669c | 1811 | struct cfq_queue *cfqq = cfqd->active_queue; |
206dc69b | 1812 | struct cfq_io_context *cic; |
7b14e3b5 JA |
1813 | unsigned long sl; |
1814 | ||
a68bbddb | 1815 | /* |
f7d7b7a7 JA |
1816 | * SSD device without seek penalty, disable idling. But only do so |
1817 | * for devices that support queuing, otherwise we still have a problem | |
1818 | * with sync vs async workloads. | |
a68bbddb | 1819 | */ |
f7d7b7a7 | 1820 | if (blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag) |
a68bbddb JA |
1821 | return; |
1822 | ||
dd67d051 | 1823 | WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list)); |
6d048f53 | 1824 | WARN_ON(cfq_cfqq_slice_new(cfqq)); |
22e2c507 JA |
1825 | |
1826 | /* | |
1827 | * idle is disabled, either manually or by past process history | |
1828 | */ | |
a6d44e98 | 1829 | if (!cfqd->cfq_slice_idle || !cfq_should_idle(cfqd, cfqq)) |
6d048f53 JA |
1830 | return; |
1831 | ||
7b679138 | 1832 | /* |
8e550632 | 1833 | * still active requests from this queue, don't idle |
7b679138 | 1834 | */ |
8e550632 | 1835 | if (cfqq->dispatched) |
7b679138 JA |
1836 | return; |
1837 | ||
22e2c507 JA |
1838 | /* |
1839 | * task has exited, don't wait | |
1840 | */ | |
206dc69b | 1841 | cic = cfqd->active_cic; |
66dac98e | 1842 | if (!cic || !atomic_read(&cic->ioc->nr_tasks)) |
6d048f53 JA |
1843 | return; |
1844 | ||
355b659c CZ |
1845 | /* |
1846 | * If our average think time is larger than the remaining time | |
1847 | * slice, then don't idle. This avoids overrunning the allotted | |
1848 | * time slice. | |
1849 | */ | |
1850 | if (sample_valid(cic->ttime_samples) && | |
1851 | (cfqq->slice_end - jiffies < cic->ttime_mean)) | |
1852 | return; | |
1853 | ||
3b18152c | 1854 | cfq_mark_cfqq_wait_request(cfqq); |
22e2c507 | 1855 | |
6d048f53 | 1856 | sl = cfqd->cfq_slice_idle; |
206dc69b | 1857 | |
7b14e3b5 | 1858 | mod_timer(&cfqd->idle_slice_timer, jiffies + sl); |
9481ffdc | 1859 | cfq_log_cfqq(cfqd, cfqq, "arm_idle: %lu", sl); |
1da177e4 LT |
1860 | } |
1861 | ||
498d3aa2 JA |
1862 | /* |
1863 | * Move request from internal lists to the request queue dispatch list. | |
1864 | */ | |
165125e1 | 1865 | static void cfq_dispatch_insert(struct request_queue *q, struct request *rq) |
1da177e4 | 1866 | { |
3ed9a296 | 1867 | struct cfq_data *cfqd = q->elevator->elevator_data; |
5e705374 | 1868 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 | 1869 | |
7b679138 JA |
1870 | cfq_log_cfqq(cfqd, cfqq, "dispatch_insert"); |
1871 | ||
06d21886 | 1872 | cfqq->next_rq = cfq_find_next_rq(cfqd, cfqq, rq); |
5380a101 | 1873 | cfq_remove_request(rq); |
6d048f53 | 1874 | cfqq->dispatched++; |
5380a101 | 1875 | elv_dispatch_sort(q, rq); |
3ed9a296 JA |
1876 | |
1877 | if (cfq_cfqq_sync(cfqq)) | |
1878 | cfqd->sync_flight++; | |
22084190 | 1879 | cfqq->nr_sectors += blk_rq_sectors(rq); |
1da177e4 LT |
1880 | } |
1881 | ||
1882 | /* | |
1883 | * return expired entry, or NULL to just start from scratch in rbtree | |
1884 | */ | |
febffd61 | 1885 | static struct request *cfq_check_fifo(struct cfq_queue *cfqq) |
1da177e4 | 1886 | { |
30996f40 | 1887 | struct request *rq = NULL; |
1da177e4 | 1888 | |
3b18152c | 1889 | if (cfq_cfqq_fifo_expire(cfqq)) |
1da177e4 | 1890 | return NULL; |
cb887411 JA |
1891 | |
1892 | cfq_mark_cfqq_fifo_expire(cfqq); | |
1893 | ||
89850f7e JA |
1894 | if (list_empty(&cfqq->fifo)) |
1895 | return NULL; | |
1da177e4 | 1896 | |
89850f7e | 1897 | rq = rq_entry_fifo(cfqq->fifo.next); |
30996f40 | 1898 | if (time_before(jiffies, rq_fifo_time(rq))) |
7b679138 | 1899 | rq = NULL; |
1da177e4 | 1900 | |
30996f40 | 1901 | cfq_log_cfqq(cfqq->cfqd, cfqq, "fifo=%p", rq); |
6d048f53 | 1902 | return rq; |
1da177e4 LT |
1903 | } |
1904 | ||
22e2c507 JA |
1905 | static inline int |
1906 | cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1907 | { | |
1908 | const int base_rq = cfqd->cfq_slice_async_rq; | |
1da177e4 | 1909 | |
22e2c507 | 1910 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); |
1da177e4 | 1911 | |
22e2c507 | 1912 | return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio)); |
1da177e4 LT |
1913 | } |
1914 | ||
df5fe3e8 JM |
1915 | /* |
1916 | * Must be called with the queue_lock held. | |
1917 | */ | |
1918 | static int cfqq_process_refs(struct cfq_queue *cfqq) | |
1919 | { | |
1920 | int process_refs, io_refs; | |
1921 | ||
1922 | io_refs = cfqq->allocated[READ] + cfqq->allocated[WRITE]; | |
1923 | process_refs = atomic_read(&cfqq->ref) - io_refs; | |
1924 | BUG_ON(process_refs < 0); | |
1925 | return process_refs; | |
1926 | } | |
1927 | ||
1928 | static void cfq_setup_merge(struct cfq_queue *cfqq, struct cfq_queue *new_cfqq) | |
1929 | { | |
e6c5bc73 | 1930 | int process_refs, new_process_refs; |
df5fe3e8 JM |
1931 | struct cfq_queue *__cfqq; |
1932 | ||
1933 | /* Avoid a circular list and skip interim queue merges */ | |
1934 | while ((__cfqq = new_cfqq->new_cfqq)) { | |
1935 | if (__cfqq == cfqq) | |
1936 | return; | |
1937 | new_cfqq = __cfqq; | |
1938 | } | |
1939 | ||
1940 | process_refs = cfqq_process_refs(cfqq); | |
1941 | /* | |
1942 | * If the process for the cfqq has gone away, there is no | |
1943 | * sense in merging the queues. | |
1944 | */ | |
1945 | if (process_refs == 0) | |
1946 | return; | |
1947 | ||
e6c5bc73 JM |
1948 | /* |
1949 | * Merge in the direction of the lesser amount of work. | |
1950 | */ | |
1951 | new_process_refs = cfqq_process_refs(new_cfqq); | |
1952 | if (new_process_refs >= process_refs) { | |
1953 | cfqq->new_cfqq = new_cfqq; | |
1954 | atomic_add(process_refs, &new_cfqq->ref); | |
1955 | } else { | |
1956 | new_cfqq->new_cfqq = cfqq; | |
1957 | atomic_add(new_process_refs, &cfqq->ref); | |
1958 | } | |
df5fe3e8 JM |
1959 | } |
1960 | ||
cdb16e8f | 1961 | static enum wl_type_t cfq_choose_wl(struct cfq_data *cfqd, |
65b32a57 | 1962 | struct cfq_group *cfqg, enum wl_prio_t prio) |
718eee05 CZ |
1963 | { |
1964 | struct cfq_queue *queue; | |
1965 | int i; | |
1966 | bool key_valid = false; | |
1967 | unsigned long lowest_key = 0; | |
1968 | enum wl_type_t cur_best = SYNC_NOIDLE_WORKLOAD; | |
1969 | ||
65b32a57 VG |
1970 | for (i = 0; i <= SYNC_WORKLOAD; ++i) { |
1971 | /* select the one with lowest rb_key */ | |
1972 | queue = cfq_rb_first(service_tree_for(cfqg, prio, i)); | |
718eee05 CZ |
1973 | if (queue && |
1974 | (!key_valid || time_before(queue->rb_key, lowest_key))) { | |
1975 | lowest_key = queue->rb_key; | |
1976 | cur_best = i; | |
1977 | key_valid = true; | |
1978 | } | |
1979 | } | |
1980 | ||
1981 | return cur_best; | |
1982 | } | |
1983 | ||
cdb16e8f | 1984 | static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg) |
718eee05 | 1985 | { |
718eee05 CZ |
1986 | unsigned slice; |
1987 | unsigned count; | |
cdb16e8f | 1988 | struct cfq_rb_root *st; |
58ff82f3 | 1989 | unsigned group_slice; |
718eee05 | 1990 | |
1fa8f6d6 VG |
1991 | if (!cfqg) { |
1992 | cfqd->serving_prio = IDLE_WORKLOAD; | |
1993 | cfqd->workload_expires = jiffies + 1; | |
1994 | return; | |
1995 | } | |
1996 | ||
718eee05 | 1997 | /* Choose next priority. RT > BE > IDLE */ |
58ff82f3 | 1998 | if (cfq_group_busy_queues_wl(RT_WORKLOAD, cfqd, cfqg)) |
718eee05 | 1999 | cfqd->serving_prio = RT_WORKLOAD; |
58ff82f3 | 2000 | else if (cfq_group_busy_queues_wl(BE_WORKLOAD, cfqd, cfqg)) |
718eee05 CZ |
2001 | cfqd->serving_prio = BE_WORKLOAD; |
2002 | else { | |
2003 | cfqd->serving_prio = IDLE_WORKLOAD; | |
2004 | cfqd->workload_expires = jiffies + 1; | |
2005 | return; | |
2006 | } | |
2007 | ||
2008 | /* | |
2009 | * For RT and BE, we have to choose also the type | |
2010 | * (SYNC, SYNC_NOIDLE, ASYNC), and to compute a workload | |
2011 | * expiration time | |
2012 | */ | |
65b32a57 | 2013 | st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type); |
cdb16e8f | 2014 | count = st->count; |
718eee05 CZ |
2015 | |
2016 | /* | |
65b32a57 | 2017 | * check workload expiration, and that we still have other queues ready |
718eee05 | 2018 | */ |
65b32a57 | 2019 | if (count && !time_after(jiffies, cfqd->workload_expires)) |
718eee05 CZ |
2020 | return; |
2021 | ||
2022 | /* otherwise select new workload type */ | |
2023 | cfqd->serving_type = | |
65b32a57 VG |
2024 | cfq_choose_wl(cfqd, cfqg, cfqd->serving_prio); |
2025 | st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type); | |
cdb16e8f | 2026 | count = st->count; |
718eee05 CZ |
2027 | |
2028 | /* | |
2029 | * the workload slice is computed as a fraction of target latency | |
2030 | * proportional to the number of queues in that workload, over | |
2031 | * all the queues in the same priority class | |
2032 | */ | |
58ff82f3 VG |
2033 | group_slice = cfq_group_slice(cfqd, cfqg); |
2034 | ||
2035 | slice = group_slice * count / | |
2036 | max_t(unsigned, cfqg->busy_queues_avg[cfqd->serving_prio], | |
2037 | cfq_group_busy_queues_wl(cfqd->serving_prio, cfqd, cfqg)); | |
718eee05 | 2038 | |
f26bd1f0 VG |
2039 | if (cfqd->serving_type == ASYNC_WORKLOAD) { |
2040 | unsigned int tmp; | |
2041 | ||
2042 | /* | |
2043 | * Async queues are currently system wide. Just taking | |
2044 | * proportion of queues with-in same group will lead to higher | |
2045 | * async ratio system wide as generally root group is going | |
2046 | * to have higher weight. A more accurate thing would be to | |
2047 | * calculate system wide asnc/sync ratio. | |
2048 | */ | |
2049 | tmp = cfq_target_latency * cfqg_busy_async_queues(cfqd, cfqg); | |
2050 | tmp = tmp/cfqd->busy_queues; | |
2051 | slice = min_t(unsigned, slice, tmp); | |
2052 | ||
718eee05 CZ |
2053 | /* async workload slice is scaled down according to |
2054 | * the sync/async slice ratio. */ | |
2055 | slice = slice * cfqd->cfq_slice[0] / cfqd->cfq_slice[1]; | |
f26bd1f0 | 2056 | } else |
718eee05 CZ |
2057 | /* sync workload slice is at least 2 * cfq_slice_idle */ |
2058 | slice = max(slice, 2 * cfqd->cfq_slice_idle); | |
2059 | ||
2060 | slice = max_t(unsigned, slice, CFQ_MIN_TT); | |
2061 | cfqd->workload_expires = jiffies + slice; | |
8e550632 | 2062 | cfqd->noidle_tree_requires_idle = false; |
718eee05 CZ |
2063 | } |
2064 | ||
1fa8f6d6 VG |
2065 | static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd) |
2066 | { | |
2067 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
25bc6b07 | 2068 | struct cfq_group *cfqg; |
1fa8f6d6 VG |
2069 | |
2070 | if (RB_EMPTY_ROOT(&st->rb)) | |
2071 | return NULL; | |
25bc6b07 VG |
2072 | cfqg = cfq_rb_first_group(st); |
2073 | st->active = &cfqg->rb_node; | |
2074 | update_min_vdisktime(st); | |
2075 | return cfqg; | |
1fa8f6d6 VG |
2076 | } |
2077 | ||
cdb16e8f VG |
2078 | static void cfq_choose_cfqg(struct cfq_data *cfqd) |
2079 | { | |
1fa8f6d6 VG |
2080 | struct cfq_group *cfqg = cfq_get_next_cfqg(cfqd); |
2081 | ||
2082 | cfqd->serving_group = cfqg; | |
dae739eb VG |
2083 | |
2084 | /* Restore the workload type data */ | |
2085 | if (cfqg->saved_workload_slice) { | |
2086 | cfqd->workload_expires = jiffies + cfqg->saved_workload_slice; | |
2087 | cfqd->serving_type = cfqg->saved_workload; | |
2088 | cfqd->serving_prio = cfqg->saved_serving_prio; | |
66ae2919 GJ |
2089 | } else |
2090 | cfqd->workload_expires = jiffies - 1; | |
2091 | ||
1fa8f6d6 | 2092 | choose_service_tree(cfqd, cfqg); |
cdb16e8f VG |
2093 | } |
2094 | ||
22e2c507 | 2095 | /* |
498d3aa2 JA |
2096 | * Select a queue for service. If we have a current active queue, |
2097 | * check whether to continue servicing it, or retrieve and set a new one. | |
22e2c507 | 2098 | */ |
1b5ed5e1 | 2099 | static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) |
1da177e4 | 2100 | { |
a36e71f9 | 2101 | struct cfq_queue *cfqq, *new_cfqq = NULL; |
1da177e4 | 2102 | |
22e2c507 JA |
2103 | cfqq = cfqd->active_queue; |
2104 | if (!cfqq) | |
2105 | goto new_queue; | |
1da177e4 | 2106 | |
f04a6424 VG |
2107 | if (!cfqd->rq_queued) |
2108 | return NULL; | |
c244bb50 VG |
2109 | |
2110 | /* | |
2111 | * We were waiting for group to get backlogged. Expire the queue | |
2112 | */ | |
2113 | if (cfq_cfqq_wait_busy(cfqq) && !RB_EMPTY_ROOT(&cfqq->sort_list)) | |
2114 | goto expire; | |
2115 | ||
22e2c507 | 2116 | /* |
6d048f53 | 2117 | * The active queue has run out of time, expire it and select new. |
22e2c507 | 2118 | */ |
7667aa06 VG |
2119 | if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq)) { |
2120 | /* | |
2121 | * If slice had not expired at the completion of last request | |
2122 | * we might not have turned on wait_busy flag. Don't expire | |
2123 | * the queue yet. Allow the group to get backlogged. | |
2124 | * | |
2125 | * The very fact that we have used the slice, that means we | |
2126 | * have been idling all along on this queue and it should be | |
2127 | * ok to wait for this request to complete. | |
2128 | */ | |
82bbbf28 VG |
2129 | if (cfqq->cfqg->nr_cfqq == 1 && RB_EMPTY_ROOT(&cfqq->sort_list) |
2130 | && cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) { | |
2131 | cfqq = NULL; | |
7667aa06 | 2132 | goto keep_queue; |
82bbbf28 | 2133 | } else |
7667aa06 VG |
2134 | goto expire; |
2135 | } | |
1da177e4 | 2136 | |
22e2c507 | 2137 | /* |
6d048f53 JA |
2138 | * The active queue has requests and isn't expired, allow it to |
2139 | * dispatch. | |
22e2c507 | 2140 | */ |
dd67d051 | 2141 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
22e2c507 | 2142 | goto keep_queue; |
6d048f53 | 2143 | |
a36e71f9 JA |
2144 | /* |
2145 | * If another queue has a request waiting within our mean seek | |
2146 | * distance, let it run. The expire code will check for close | |
2147 | * cooperators and put the close queue at the front of the service | |
df5fe3e8 | 2148 | * tree. If possible, merge the expiring queue with the new cfqq. |
a36e71f9 | 2149 | */ |
b3b6d040 | 2150 | new_cfqq = cfq_close_cooperator(cfqd, cfqq); |
df5fe3e8 JM |
2151 | if (new_cfqq) { |
2152 | if (!cfqq->new_cfqq) | |
2153 | cfq_setup_merge(cfqq, new_cfqq); | |
a36e71f9 | 2154 | goto expire; |
df5fe3e8 | 2155 | } |
a36e71f9 | 2156 | |
6d048f53 JA |
2157 | /* |
2158 | * No requests pending. If the active queue still has requests in | |
2159 | * flight or is idling for a new request, allow either of these | |
2160 | * conditions to happen (or time out) before selecting a new queue. | |
2161 | */ | |
cc197479 | 2162 | if (timer_pending(&cfqd->idle_slice_timer) || |
a6d44e98 | 2163 | (cfqq->dispatched && cfq_should_idle(cfqd, cfqq))) { |
caaa5f9f JA |
2164 | cfqq = NULL; |
2165 | goto keep_queue; | |
22e2c507 JA |
2166 | } |
2167 | ||
3b18152c | 2168 | expire: |
6084cdda | 2169 | cfq_slice_expired(cfqd, 0); |
3b18152c | 2170 | new_queue: |
718eee05 CZ |
2171 | /* |
2172 | * Current queue expired. Check if we have to switch to a new | |
2173 | * service tree | |
2174 | */ | |
2175 | if (!new_cfqq) | |
cdb16e8f | 2176 | cfq_choose_cfqg(cfqd); |
718eee05 | 2177 | |
a36e71f9 | 2178 | cfqq = cfq_set_active_queue(cfqd, new_cfqq); |
22e2c507 | 2179 | keep_queue: |
3b18152c | 2180 | return cfqq; |
22e2c507 JA |
2181 | } |
2182 | ||
febffd61 | 2183 | static int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq) |
d9e7620e JA |
2184 | { |
2185 | int dispatched = 0; | |
2186 | ||
2187 | while (cfqq->next_rq) { | |
2188 | cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq); | |
2189 | dispatched++; | |
2190 | } | |
2191 | ||
2192 | BUG_ON(!list_empty(&cfqq->fifo)); | |
f04a6424 VG |
2193 | |
2194 | /* By default cfqq is not expired if it is empty. Do it explicitly */ | |
2195 | __cfq_slice_expired(cfqq->cfqd, cfqq, 0); | |
d9e7620e JA |
2196 | return dispatched; |
2197 | } | |
2198 | ||
498d3aa2 JA |
2199 | /* |
2200 | * Drain our current requests. Used for barriers and when switching | |
2201 | * io schedulers on-the-fly. | |
2202 | */ | |
d9e7620e | 2203 | static int cfq_forced_dispatch(struct cfq_data *cfqd) |
1b5ed5e1 | 2204 | { |
0871714e | 2205 | struct cfq_queue *cfqq; |
d9e7620e | 2206 | int dispatched = 0; |
cdb16e8f | 2207 | |
f04a6424 VG |
2208 | while ((cfqq = cfq_get_next_queue_forced(cfqd)) != NULL) |
2209 | dispatched += __cfq_forced_dispatch_cfqq(cfqq); | |
1b5ed5e1 | 2210 | |
6084cdda | 2211 | cfq_slice_expired(cfqd, 0); |
1b5ed5e1 TH |
2212 | BUG_ON(cfqd->busy_queues); |
2213 | ||
6923715a | 2214 | cfq_log(cfqd, "forced_dispatch=%d", dispatched); |
1b5ed5e1 TH |
2215 | return dispatched; |
2216 | } | |
2217 | ||
0b182d61 | 2218 | static bool cfq_may_dispatch(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
2f5cb738 | 2219 | { |
2f5cb738 | 2220 | unsigned int max_dispatch; |
22e2c507 | 2221 | |
5ad531db JA |
2222 | /* |
2223 | * Drain async requests before we start sync IO | |
2224 | */ | |
a6d44e98 | 2225 | if (cfq_should_idle(cfqd, cfqq) && cfqd->rq_in_driver[BLK_RW_ASYNC]) |
0b182d61 | 2226 | return false; |
5ad531db | 2227 | |
2f5cb738 JA |
2228 | /* |
2229 | * If this is an async queue and we have sync IO in flight, let it wait | |
2230 | */ | |
2231 | if (cfqd->sync_flight && !cfq_cfqq_sync(cfqq)) | |
0b182d61 | 2232 | return false; |
2f5cb738 JA |
2233 | |
2234 | max_dispatch = cfqd->cfq_quantum; | |
2235 | if (cfq_class_idle(cfqq)) | |
2236 | max_dispatch = 1; | |
b4878f24 | 2237 | |
2f5cb738 JA |
2238 | /* |
2239 | * Does this cfqq already have too much IO in flight? | |
2240 | */ | |
2241 | if (cfqq->dispatched >= max_dispatch) { | |
2242 | /* | |
2243 | * idle queue must always only have a single IO in flight | |
2244 | */ | |
3ed9a296 | 2245 | if (cfq_class_idle(cfqq)) |
0b182d61 | 2246 | return false; |
3ed9a296 | 2247 | |
2f5cb738 JA |
2248 | /* |
2249 | * We have other queues, don't allow more IO from this one | |
2250 | */ | |
2251 | if (cfqd->busy_queues > 1) | |
0b182d61 | 2252 | return false; |
9ede209e | 2253 | |
365722bb | 2254 | /* |
474b18cc | 2255 | * Sole queue user, no limit |
365722bb | 2256 | */ |
474b18cc | 2257 | max_dispatch = -1; |
8e296755 JA |
2258 | } |
2259 | ||
2260 | /* | |
2261 | * Async queues must wait a bit before being allowed dispatch. | |
2262 | * We also ramp up the dispatch depth gradually for async IO, | |
2263 | * based on the last sync IO we serviced | |
2264 | */ | |
963b72fc | 2265 | if (!cfq_cfqq_sync(cfqq) && cfqd->cfq_latency) { |
573412b2 | 2266 | unsigned long last_sync = jiffies - cfqd->last_delayed_sync; |
8e296755 | 2267 | unsigned int depth; |
365722bb | 2268 | |
61f0c1dc | 2269 | depth = last_sync / cfqd->cfq_slice[1]; |
e00c54c3 JA |
2270 | if (!depth && !cfqq->dispatched) |
2271 | depth = 1; | |
8e296755 JA |
2272 | if (depth < max_dispatch) |
2273 | max_dispatch = depth; | |
2f5cb738 | 2274 | } |
3ed9a296 | 2275 | |
0b182d61 JA |
2276 | /* |
2277 | * If we're below the current max, allow a dispatch | |
2278 | */ | |
2279 | return cfqq->dispatched < max_dispatch; | |
2280 | } | |
2281 | ||
2282 | /* | |
2283 | * Dispatch a request from cfqq, moving them to the request queue | |
2284 | * dispatch list. | |
2285 | */ | |
2286 | static bool cfq_dispatch_request(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
2287 | { | |
2288 | struct request *rq; | |
2289 | ||
2290 | BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list)); | |
2291 | ||
2292 | if (!cfq_may_dispatch(cfqd, cfqq)) | |
2293 | return false; | |
2294 | ||
2295 | /* | |
2296 | * follow expired path, else get first next available | |
2297 | */ | |
2298 | rq = cfq_check_fifo(cfqq); | |
2299 | if (!rq) | |
2300 | rq = cfqq->next_rq; | |
2301 | ||
2302 | /* | |
2303 | * insert request into driver dispatch list | |
2304 | */ | |
2305 | cfq_dispatch_insert(cfqd->queue, rq); | |
2306 | ||
2307 | if (!cfqd->active_cic) { | |
2308 | struct cfq_io_context *cic = RQ_CIC(rq); | |
2309 | ||
2310 | atomic_long_inc(&cic->ioc->refcount); | |
2311 | cfqd->active_cic = cic; | |
2312 | } | |
2313 | ||
2314 | return true; | |
2315 | } | |
2316 | ||
2317 | /* | |
2318 | * Find the cfqq that we need to service and move a request from that to the | |
2319 | * dispatch list | |
2320 | */ | |
2321 | static int cfq_dispatch_requests(struct request_queue *q, int force) | |
2322 | { | |
2323 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
2324 | struct cfq_queue *cfqq; | |
2325 | ||
2326 | if (!cfqd->busy_queues) | |
2327 | return 0; | |
2328 | ||
2329 | if (unlikely(force)) | |
2330 | return cfq_forced_dispatch(cfqd); | |
2331 | ||
2332 | cfqq = cfq_select_queue(cfqd); | |
2333 | if (!cfqq) | |
8e296755 JA |
2334 | return 0; |
2335 | ||
2f5cb738 | 2336 | /* |
0b182d61 | 2337 | * Dispatch a request from this cfqq, if it is allowed |
2f5cb738 | 2338 | */ |
0b182d61 JA |
2339 | if (!cfq_dispatch_request(cfqd, cfqq)) |
2340 | return 0; | |
2341 | ||
2f5cb738 | 2342 | cfqq->slice_dispatch++; |
b029195d | 2343 | cfq_clear_cfqq_must_dispatch(cfqq); |
22e2c507 | 2344 | |
2f5cb738 JA |
2345 | /* |
2346 | * expire an async queue immediately if it has used up its slice. idle | |
2347 | * queue always expire after 1 dispatch round. | |
2348 | */ | |
2349 | if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) && | |
2350 | cfqq->slice_dispatch >= cfq_prio_to_maxrq(cfqd, cfqq)) || | |
2351 | cfq_class_idle(cfqq))) { | |
2352 | cfqq->slice_end = jiffies + 1; | |
2353 | cfq_slice_expired(cfqd, 0); | |
1da177e4 LT |
2354 | } |
2355 | ||
b217a903 | 2356 | cfq_log_cfqq(cfqd, cfqq, "dispatched a request"); |
2f5cb738 | 2357 | return 1; |
1da177e4 LT |
2358 | } |
2359 | ||
1da177e4 | 2360 | /* |
5e705374 JA |
2361 | * task holds one reference to the queue, dropped when task exits. each rq |
2362 | * in-flight on this queue also holds a reference, dropped when rq is freed. | |
1da177e4 | 2363 | * |
b1c35769 | 2364 | * Each cfq queue took a reference on the parent group. Drop it now. |
1da177e4 LT |
2365 | * queue lock must be held here. |
2366 | */ | |
2367 | static void cfq_put_queue(struct cfq_queue *cfqq) | |
2368 | { | |
22e2c507 | 2369 | struct cfq_data *cfqd = cfqq->cfqd; |
878eaddd | 2370 | struct cfq_group *cfqg, *orig_cfqg; |
22e2c507 JA |
2371 | |
2372 | BUG_ON(atomic_read(&cfqq->ref) <= 0); | |
1da177e4 LT |
2373 | |
2374 | if (!atomic_dec_and_test(&cfqq->ref)) | |
2375 | return; | |
2376 | ||
7b679138 | 2377 | cfq_log_cfqq(cfqd, cfqq, "put_queue"); |
1da177e4 | 2378 | BUG_ON(rb_first(&cfqq->sort_list)); |
22e2c507 | 2379 | BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]); |
b1c35769 | 2380 | cfqg = cfqq->cfqg; |
878eaddd | 2381 | orig_cfqg = cfqq->orig_cfqg; |
1da177e4 | 2382 | |
28f95cbc | 2383 | if (unlikely(cfqd->active_queue == cfqq)) { |
6084cdda | 2384 | __cfq_slice_expired(cfqd, cfqq, 0); |
23e018a1 | 2385 | cfq_schedule_dispatch(cfqd); |
28f95cbc | 2386 | } |
22e2c507 | 2387 | |
f04a6424 | 2388 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
1da177e4 | 2389 | kmem_cache_free(cfq_pool, cfqq); |
b1c35769 | 2390 | cfq_put_cfqg(cfqg); |
878eaddd VG |
2391 | if (orig_cfqg) |
2392 | cfq_put_cfqg(orig_cfqg); | |
1da177e4 LT |
2393 | } |
2394 | ||
d6de8be7 JA |
2395 | /* |
2396 | * Must always be called with the rcu_read_lock() held | |
2397 | */ | |
07416d29 JA |
2398 | static void |
2399 | __call_for_each_cic(struct io_context *ioc, | |
2400 | void (*func)(struct io_context *, struct cfq_io_context *)) | |
2401 | { | |
2402 | struct cfq_io_context *cic; | |
2403 | struct hlist_node *n; | |
2404 | ||
2405 | hlist_for_each_entry_rcu(cic, n, &ioc->cic_list, cic_list) | |
2406 | func(ioc, cic); | |
2407 | } | |
2408 | ||
4ac845a2 | 2409 | /* |
34e6bbf2 | 2410 | * Call func for each cic attached to this ioc. |
4ac845a2 | 2411 | */ |
34e6bbf2 | 2412 | static void |
4ac845a2 JA |
2413 | call_for_each_cic(struct io_context *ioc, |
2414 | void (*func)(struct io_context *, struct cfq_io_context *)) | |
1da177e4 | 2415 | { |
4ac845a2 | 2416 | rcu_read_lock(); |
07416d29 | 2417 | __call_for_each_cic(ioc, func); |
4ac845a2 | 2418 | rcu_read_unlock(); |
34e6bbf2 FC |
2419 | } |
2420 | ||
2421 | static void cfq_cic_free_rcu(struct rcu_head *head) | |
2422 | { | |
2423 | struct cfq_io_context *cic; | |
2424 | ||
2425 | cic = container_of(head, struct cfq_io_context, rcu_head); | |
2426 | ||
2427 | kmem_cache_free(cfq_ioc_pool, cic); | |
245b2e70 | 2428 | elv_ioc_count_dec(cfq_ioc_count); |
34e6bbf2 | 2429 | |
9a11b4ed JA |
2430 | if (ioc_gone) { |
2431 | /* | |
2432 | * CFQ scheduler is exiting, grab exit lock and check | |
2433 | * the pending io context count. If it hits zero, | |
2434 | * complete ioc_gone and set it back to NULL | |
2435 | */ | |
2436 | spin_lock(&ioc_gone_lock); | |
245b2e70 | 2437 | if (ioc_gone && !elv_ioc_count_read(cfq_ioc_count)) { |
9a11b4ed JA |
2438 | complete(ioc_gone); |
2439 | ioc_gone = NULL; | |
2440 | } | |
2441 | spin_unlock(&ioc_gone_lock); | |
2442 | } | |
34e6bbf2 | 2443 | } |
4ac845a2 | 2444 | |
34e6bbf2 FC |
2445 | static void cfq_cic_free(struct cfq_io_context *cic) |
2446 | { | |
2447 | call_rcu(&cic->rcu_head, cfq_cic_free_rcu); | |
4ac845a2 JA |
2448 | } |
2449 | ||
2450 | static void cic_free_func(struct io_context *ioc, struct cfq_io_context *cic) | |
2451 | { | |
2452 | unsigned long flags; | |
2453 | ||
2454 | BUG_ON(!cic->dead_key); | |
2455 | ||
2456 | spin_lock_irqsave(&ioc->lock, flags); | |
2457 | radix_tree_delete(&ioc->radix_root, cic->dead_key); | |
ffc4e759 | 2458 | hlist_del_rcu(&cic->cic_list); |
4ac845a2 JA |
2459 | spin_unlock_irqrestore(&ioc->lock, flags); |
2460 | ||
34e6bbf2 | 2461 | cfq_cic_free(cic); |
4ac845a2 JA |
2462 | } |
2463 | ||
d6de8be7 JA |
2464 | /* |
2465 | * Must be called with rcu_read_lock() held or preemption otherwise disabled. | |
2466 | * Only two callers of this - ->dtor() which is called with the rcu_read_lock(), | |
2467 | * and ->trim() which is called with the task lock held | |
2468 | */ | |
4ac845a2 JA |
2469 | static void cfq_free_io_context(struct io_context *ioc) |
2470 | { | |
4ac845a2 | 2471 | /* |
34e6bbf2 FC |
2472 | * ioc->refcount is zero here, or we are called from elv_unregister(), |
2473 | * so no more cic's are allowed to be linked into this ioc. So it | |
2474 | * should be ok to iterate over the known list, we will see all cic's | |
2475 | * since no new ones are added. | |
4ac845a2 | 2476 | */ |
07416d29 | 2477 | __call_for_each_cic(ioc, cic_free_func); |
1da177e4 LT |
2478 | } |
2479 | ||
89850f7e | 2480 | static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 2481 | { |
df5fe3e8 JM |
2482 | struct cfq_queue *__cfqq, *next; |
2483 | ||
28f95cbc | 2484 | if (unlikely(cfqq == cfqd->active_queue)) { |
6084cdda | 2485 | __cfq_slice_expired(cfqd, cfqq, 0); |
23e018a1 | 2486 | cfq_schedule_dispatch(cfqd); |
28f95cbc | 2487 | } |
22e2c507 | 2488 | |
df5fe3e8 JM |
2489 | /* |
2490 | * If this queue was scheduled to merge with another queue, be | |
2491 | * sure to drop the reference taken on that queue (and others in | |
2492 | * the merge chain). See cfq_setup_merge and cfq_merge_cfqqs. | |
2493 | */ | |
2494 | __cfqq = cfqq->new_cfqq; | |
2495 | while (__cfqq) { | |
2496 | if (__cfqq == cfqq) { | |
2497 | WARN(1, "cfqq->new_cfqq loop detected\n"); | |
2498 | break; | |
2499 | } | |
2500 | next = __cfqq->new_cfqq; | |
2501 | cfq_put_queue(__cfqq); | |
2502 | __cfqq = next; | |
2503 | } | |
2504 | ||
89850f7e JA |
2505 | cfq_put_queue(cfqq); |
2506 | } | |
22e2c507 | 2507 | |
89850f7e JA |
2508 | static void __cfq_exit_single_io_context(struct cfq_data *cfqd, |
2509 | struct cfq_io_context *cic) | |
2510 | { | |
4faa3c81 FC |
2511 | struct io_context *ioc = cic->ioc; |
2512 | ||
fc46379d | 2513 | list_del_init(&cic->queue_list); |
4ac845a2 JA |
2514 | |
2515 | /* | |
2516 | * Make sure key == NULL is seen for dead queues | |
2517 | */ | |
fc46379d | 2518 | smp_wmb(); |
4ac845a2 | 2519 | cic->dead_key = (unsigned long) cic->key; |
fc46379d JA |
2520 | cic->key = NULL; |
2521 | ||
4faa3c81 FC |
2522 | if (ioc->ioc_data == cic) |
2523 | rcu_assign_pointer(ioc->ioc_data, NULL); | |
2524 | ||
ff6657c6 JA |
2525 | if (cic->cfqq[BLK_RW_ASYNC]) { |
2526 | cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_ASYNC]); | |
2527 | cic->cfqq[BLK_RW_ASYNC] = NULL; | |
12a05732 AV |
2528 | } |
2529 | ||
ff6657c6 JA |
2530 | if (cic->cfqq[BLK_RW_SYNC]) { |
2531 | cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_SYNC]); | |
2532 | cic->cfqq[BLK_RW_SYNC] = NULL; | |
12a05732 | 2533 | } |
89850f7e JA |
2534 | } |
2535 | ||
4ac845a2 JA |
2536 | static void cfq_exit_single_io_context(struct io_context *ioc, |
2537 | struct cfq_io_context *cic) | |
89850f7e JA |
2538 | { |
2539 | struct cfq_data *cfqd = cic->key; | |
2540 | ||
89850f7e | 2541 | if (cfqd) { |
165125e1 | 2542 | struct request_queue *q = cfqd->queue; |
4ac845a2 | 2543 | unsigned long flags; |
89850f7e | 2544 | |
4ac845a2 | 2545 | spin_lock_irqsave(q->queue_lock, flags); |
62c1fe9d JA |
2546 | |
2547 | /* | |
2548 | * Ensure we get a fresh copy of the ->key to prevent | |
2549 | * race between exiting task and queue | |
2550 | */ | |
2551 | smp_read_barrier_depends(); | |
2552 | if (cic->key) | |
2553 | __cfq_exit_single_io_context(cfqd, cic); | |
2554 | ||
4ac845a2 | 2555 | spin_unlock_irqrestore(q->queue_lock, flags); |
89850f7e | 2556 | } |
1da177e4 LT |
2557 | } |
2558 | ||
498d3aa2 JA |
2559 | /* |
2560 | * The process that ioc belongs to has exited, we need to clean up | |
2561 | * and put the internal structures we have that belongs to that process. | |
2562 | */ | |
e2d74ac0 | 2563 | static void cfq_exit_io_context(struct io_context *ioc) |
1da177e4 | 2564 | { |
4ac845a2 | 2565 | call_for_each_cic(ioc, cfq_exit_single_io_context); |
1da177e4 LT |
2566 | } |
2567 | ||
22e2c507 | 2568 | static struct cfq_io_context * |
8267e268 | 2569 | cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
1da177e4 | 2570 | { |
b5deef90 | 2571 | struct cfq_io_context *cic; |
1da177e4 | 2572 | |
94f6030c CL |
2573 | cic = kmem_cache_alloc_node(cfq_ioc_pool, gfp_mask | __GFP_ZERO, |
2574 | cfqd->queue->node); | |
1da177e4 | 2575 | if (cic) { |
22e2c507 | 2576 | cic->last_end_request = jiffies; |
553698f9 | 2577 | INIT_LIST_HEAD(&cic->queue_list); |
ffc4e759 | 2578 | INIT_HLIST_NODE(&cic->cic_list); |
22e2c507 JA |
2579 | cic->dtor = cfq_free_io_context; |
2580 | cic->exit = cfq_exit_io_context; | |
245b2e70 | 2581 | elv_ioc_count_inc(cfq_ioc_count); |
1da177e4 LT |
2582 | } |
2583 | ||
2584 | return cic; | |
2585 | } | |
2586 | ||
fd0928df | 2587 | static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc) |
22e2c507 JA |
2588 | { |
2589 | struct task_struct *tsk = current; | |
2590 | int ioprio_class; | |
2591 | ||
3b18152c | 2592 | if (!cfq_cfqq_prio_changed(cfqq)) |
22e2c507 JA |
2593 | return; |
2594 | ||
fd0928df | 2595 | ioprio_class = IOPRIO_PRIO_CLASS(ioc->ioprio); |
22e2c507 | 2596 | switch (ioprio_class) { |
fe094d98 JA |
2597 | default: |
2598 | printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class); | |
2599 | case IOPRIO_CLASS_NONE: | |
2600 | /* | |
6d63c275 | 2601 | * no prio set, inherit CPU scheduling settings |
fe094d98 JA |
2602 | */ |
2603 | cfqq->ioprio = task_nice_ioprio(tsk); | |
6d63c275 | 2604 | cfqq->ioprio_class = task_nice_ioclass(tsk); |
fe094d98 JA |
2605 | break; |
2606 | case IOPRIO_CLASS_RT: | |
2607 | cfqq->ioprio = task_ioprio(ioc); | |
2608 | cfqq->ioprio_class = IOPRIO_CLASS_RT; | |
2609 | break; | |
2610 | case IOPRIO_CLASS_BE: | |
2611 | cfqq->ioprio = task_ioprio(ioc); | |
2612 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
2613 | break; | |
2614 | case IOPRIO_CLASS_IDLE: | |
2615 | cfqq->ioprio_class = IOPRIO_CLASS_IDLE; | |
2616 | cfqq->ioprio = 7; | |
2617 | cfq_clear_cfqq_idle_window(cfqq); | |
2618 | break; | |
22e2c507 JA |
2619 | } |
2620 | ||
2621 | /* | |
2622 | * keep track of original prio settings in case we have to temporarily | |
2623 | * elevate the priority of this queue | |
2624 | */ | |
2625 | cfqq->org_ioprio = cfqq->ioprio; | |
2626 | cfqq->org_ioprio_class = cfqq->ioprio_class; | |
3b18152c | 2627 | cfq_clear_cfqq_prio_changed(cfqq); |
22e2c507 JA |
2628 | } |
2629 | ||
febffd61 | 2630 | static void changed_ioprio(struct io_context *ioc, struct cfq_io_context *cic) |
22e2c507 | 2631 | { |
478a82b0 AV |
2632 | struct cfq_data *cfqd = cic->key; |
2633 | struct cfq_queue *cfqq; | |
c1b707d2 | 2634 | unsigned long flags; |
35e6077c | 2635 | |
caaa5f9f JA |
2636 | if (unlikely(!cfqd)) |
2637 | return; | |
2638 | ||
c1b707d2 | 2639 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); |
caaa5f9f | 2640 | |
ff6657c6 | 2641 | cfqq = cic->cfqq[BLK_RW_ASYNC]; |
caaa5f9f JA |
2642 | if (cfqq) { |
2643 | struct cfq_queue *new_cfqq; | |
ff6657c6 JA |
2644 | new_cfqq = cfq_get_queue(cfqd, BLK_RW_ASYNC, cic->ioc, |
2645 | GFP_ATOMIC); | |
caaa5f9f | 2646 | if (new_cfqq) { |
ff6657c6 | 2647 | cic->cfqq[BLK_RW_ASYNC] = new_cfqq; |
caaa5f9f JA |
2648 | cfq_put_queue(cfqq); |
2649 | } | |
22e2c507 | 2650 | } |
caaa5f9f | 2651 | |
ff6657c6 | 2652 | cfqq = cic->cfqq[BLK_RW_SYNC]; |
caaa5f9f JA |
2653 | if (cfqq) |
2654 | cfq_mark_cfqq_prio_changed(cfqq); | |
2655 | ||
c1b707d2 | 2656 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); |
22e2c507 JA |
2657 | } |
2658 | ||
fc46379d | 2659 | static void cfq_ioc_set_ioprio(struct io_context *ioc) |
22e2c507 | 2660 | { |
4ac845a2 | 2661 | call_for_each_cic(ioc, changed_ioprio); |
fc46379d | 2662 | ioc->ioprio_changed = 0; |
22e2c507 JA |
2663 | } |
2664 | ||
d5036d77 | 2665 | static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
a6151c3a | 2666 | pid_t pid, bool is_sync) |
d5036d77 JA |
2667 | { |
2668 | RB_CLEAR_NODE(&cfqq->rb_node); | |
2669 | RB_CLEAR_NODE(&cfqq->p_node); | |
2670 | INIT_LIST_HEAD(&cfqq->fifo); | |
2671 | ||
2672 | atomic_set(&cfqq->ref, 0); | |
2673 | cfqq->cfqd = cfqd; | |
2674 | ||
2675 | cfq_mark_cfqq_prio_changed(cfqq); | |
2676 | ||
2677 | if (is_sync) { | |
2678 | if (!cfq_class_idle(cfqq)) | |
2679 | cfq_mark_cfqq_idle_window(cfqq); | |
2680 | cfq_mark_cfqq_sync(cfqq); | |
2681 | } | |
2682 | cfqq->pid = pid; | |
2683 | } | |
2684 | ||
24610333 VG |
2685 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
2686 | static void changed_cgroup(struct io_context *ioc, struct cfq_io_context *cic) | |
2687 | { | |
2688 | struct cfq_queue *sync_cfqq = cic_to_cfqq(cic, 1); | |
2689 | struct cfq_data *cfqd = cic->key; | |
2690 | unsigned long flags; | |
2691 | struct request_queue *q; | |
2692 | ||
2693 | if (unlikely(!cfqd)) | |
2694 | return; | |
2695 | ||
2696 | q = cfqd->queue; | |
2697 | ||
2698 | spin_lock_irqsave(q->queue_lock, flags); | |
2699 | ||
2700 | if (sync_cfqq) { | |
2701 | /* | |
2702 | * Drop reference to sync queue. A new sync queue will be | |
2703 | * assigned in new group upon arrival of a fresh request. | |
2704 | */ | |
2705 | cfq_log_cfqq(cfqd, sync_cfqq, "changed cgroup"); | |
2706 | cic_set_cfqq(cic, NULL, 1); | |
2707 | cfq_put_queue(sync_cfqq); | |
2708 | } | |
2709 | ||
2710 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2711 | } | |
2712 | ||
2713 | static void cfq_ioc_set_cgroup(struct io_context *ioc) | |
2714 | { | |
2715 | call_for_each_cic(ioc, changed_cgroup); | |
2716 | ioc->cgroup_changed = 0; | |
2717 | } | |
2718 | #endif /* CONFIG_CFQ_GROUP_IOSCHED */ | |
2719 | ||
22e2c507 | 2720 | static struct cfq_queue * |
a6151c3a | 2721 | cfq_find_alloc_queue(struct cfq_data *cfqd, bool is_sync, |
fd0928df | 2722 | struct io_context *ioc, gfp_t gfp_mask) |
22e2c507 | 2723 | { |
22e2c507 | 2724 | struct cfq_queue *cfqq, *new_cfqq = NULL; |
91fac317 | 2725 | struct cfq_io_context *cic; |
cdb16e8f | 2726 | struct cfq_group *cfqg; |
22e2c507 JA |
2727 | |
2728 | retry: | |
cdb16e8f | 2729 | cfqg = cfq_get_cfqg(cfqd, 1); |
4ac845a2 | 2730 | cic = cfq_cic_lookup(cfqd, ioc); |
91fac317 VT |
2731 | /* cic always exists here */ |
2732 | cfqq = cic_to_cfqq(cic, is_sync); | |
22e2c507 | 2733 | |
6118b70b JA |
2734 | /* |
2735 | * Always try a new alloc if we fell back to the OOM cfqq | |
2736 | * originally, since it should just be a temporary situation. | |
2737 | */ | |
2738 | if (!cfqq || cfqq == &cfqd->oom_cfqq) { | |
2739 | cfqq = NULL; | |
22e2c507 JA |
2740 | if (new_cfqq) { |
2741 | cfqq = new_cfqq; | |
2742 | new_cfqq = NULL; | |
2743 | } else if (gfp_mask & __GFP_WAIT) { | |
2744 | spin_unlock_irq(cfqd->queue->queue_lock); | |
94f6030c | 2745 | new_cfqq = kmem_cache_alloc_node(cfq_pool, |
6118b70b | 2746 | gfp_mask | __GFP_ZERO, |
94f6030c | 2747 | cfqd->queue->node); |
22e2c507 | 2748 | spin_lock_irq(cfqd->queue->queue_lock); |
6118b70b JA |
2749 | if (new_cfqq) |
2750 | goto retry; | |
22e2c507 | 2751 | } else { |
94f6030c CL |
2752 | cfqq = kmem_cache_alloc_node(cfq_pool, |
2753 | gfp_mask | __GFP_ZERO, | |
2754 | cfqd->queue->node); | |
22e2c507 JA |
2755 | } |
2756 | ||
6118b70b JA |
2757 | if (cfqq) { |
2758 | cfq_init_cfqq(cfqd, cfqq, current->pid, is_sync); | |
2759 | cfq_init_prio_data(cfqq, ioc); | |
cdb16e8f | 2760 | cfq_link_cfqq_cfqg(cfqq, cfqg); |
6118b70b JA |
2761 | cfq_log_cfqq(cfqd, cfqq, "alloced"); |
2762 | } else | |
2763 | cfqq = &cfqd->oom_cfqq; | |
22e2c507 JA |
2764 | } |
2765 | ||
2766 | if (new_cfqq) | |
2767 | kmem_cache_free(cfq_pool, new_cfqq); | |
2768 | ||
22e2c507 JA |
2769 | return cfqq; |
2770 | } | |
2771 | ||
c2dea2d1 VT |
2772 | static struct cfq_queue ** |
2773 | cfq_async_queue_prio(struct cfq_data *cfqd, int ioprio_class, int ioprio) | |
2774 | { | |
fe094d98 | 2775 | switch (ioprio_class) { |
c2dea2d1 VT |
2776 | case IOPRIO_CLASS_RT: |
2777 | return &cfqd->async_cfqq[0][ioprio]; | |
2778 | case IOPRIO_CLASS_BE: | |
2779 | return &cfqd->async_cfqq[1][ioprio]; | |
2780 | case IOPRIO_CLASS_IDLE: | |
2781 | return &cfqd->async_idle_cfqq; | |
2782 | default: | |
2783 | BUG(); | |
2784 | } | |
2785 | } | |
2786 | ||
15c31be4 | 2787 | static struct cfq_queue * |
a6151c3a | 2788 | cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct io_context *ioc, |
15c31be4 JA |
2789 | gfp_t gfp_mask) |
2790 | { | |
fd0928df JA |
2791 | const int ioprio = task_ioprio(ioc); |
2792 | const int ioprio_class = task_ioprio_class(ioc); | |
c2dea2d1 | 2793 | struct cfq_queue **async_cfqq = NULL; |
15c31be4 JA |
2794 | struct cfq_queue *cfqq = NULL; |
2795 | ||
c2dea2d1 VT |
2796 | if (!is_sync) { |
2797 | async_cfqq = cfq_async_queue_prio(cfqd, ioprio_class, ioprio); | |
2798 | cfqq = *async_cfqq; | |
2799 | } | |
2800 | ||
6118b70b | 2801 | if (!cfqq) |
fd0928df | 2802 | cfqq = cfq_find_alloc_queue(cfqd, is_sync, ioc, gfp_mask); |
15c31be4 JA |
2803 | |
2804 | /* | |
2805 | * pin the queue now that it's allocated, scheduler exit will prune it | |
2806 | */ | |
c2dea2d1 | 2807 | if (!is_sync && !(*async_cfqq)) { |
15c31be4 | 2808 | atomic_inc(&cfqq->ref); |
c2dea2d1 | 2809 | *async_cfqq = cfqq; |
15c31be4 JA |
2810 | } |
2811 | ||
2812 | atomic_inc(&cfqq->ref); | |
2813 | return cfqq; | |
2814 | } | |
2815 | ||
498d3aa2 JA |
2816 | /* |
2817 | * We drop cfq io contexts lazily, so we may find a dead one. | |
2818 | */ | |
dbecf3ab | 2819 | static void |
4ac845a2 JA |
2820 | cfq_drop_dead_cic(struct cfq_data *cfqd, struct io_context *ioc, |
2821 | struct cfq_io_context *cic) | |
dbecf3ab | 2822 | { |
4ac845a2 JA |
2823 | unsigned long flags; |
2824 | ||
fc46379d | 2825 | WARN_ON(!list_empty(&cic->queue_list)); |
597bc485 | 2826 | |
4ac845a2 JA |
2827 | spin_lock_irqsave(&ioc->lock, flags); |
2828 | ||
4faa3c81 | 2829 | BUG_ON(ioc->ioc_data == cic); |
597bc485 | 2830 | |
4ac845a2 | 2831 | radix_tree_delete(&ioc->radix_root, (unsigned long) cfqd); |
ffc4e759 | 2832 | hlist_del_rcu(&cic->cic_list); |
4ac845a2 JA |
2833 | spin_unlock_irqrestore(&ioc->lock, flags); |
2834 | ||
2835 | cfq_cic_free(cic); | |
dbecf3ab OH |
2836 | } |
2837 | ||
e2d74ac0 | 2838 | static struct cfq_io_context * |
4ac845a2 | 2839 | cfq_cic_lookup(struct cfq_data *cfqd, struct io_context *ioc) |
e2d74ac0 | 2840 | { |
e2d74ac0 | 2841 | struct cfq_io_context *cic; |
d6de8be7 | 2842 | unsigned long flags; |
4ac845a2 | 2843 | void *k; |
e2d74ac0 | 2844 | |
91fac317 VT |
2845 | if (unlikely(!ioc)) |
2846 | return NULL; | |
2847 | ||
d6de8be7 JA |
2848 | rcu_read_lock(); |
2849 | ||
597bc485 JA |
2850 | /* |
2851 | * we maintain a last-hit cache, to avoid browsing over the tree | |
2852 | */ | |
4ac845a2 | 2853 | cic = rcu_dereference(ioc->ioc_data); |
d6de8be7 JA |
2854 | if (cic && cic->key == cfqd) { |
2855 | rcu_read_unlock(); | |
597bc485 | 2856 | return cic; |
d6de8be7 | 2857 | } |
597bc485 | 2858 | |
4ac845a2 | 2859 | do { |
4ac845a2 JA |
2860 | cic = radix_tree_lookup(&ioc->radix_root, (unsigned long) cfqd); |
2861 | rcu_read_unlock(); | |
2862 | if (!cic) | |
2863 | break; | |
be3b0753 OH |
2864 | /* ->key must be copied to avoid race with cfq_exit_queue() */ |
2865 | k = cic->key; | |
2866 | if (unlikely(!k)) { | |
4ac845a2 | 2867 | cfq_drop_dead_cic(cfqd, ioc, cic); |
d6de8be7 | 2868 | rcu_read_lock(); |
4ac845a2 | 2869 | continue; |
dbecf3ab | 2870 | } |
e2d74ac0 | 2871 | |
d6de8be7 | 2872 | spin_lock_irqsave(&ioc->lock, flags); |
4ac845a2 | 2873 | rcu_assign_pointer(ioc->ioc_data, cic); |
d6de8be7 | 2874 | spin_unlock_irqrestore(&ioc->lock, flags); |
4ac845a2 JA |
2875 | break; |
2876 | } while (1); | |
e2d74ac0 | 2877 | |
4ac845a2 | 2878 | return cic; |
e2d74ac0 JA |
2879 | } |
2880 | ||
4ac845a2 JA |
2881 | /* |
2882 | * Add cic into ioc, using cfqd as the search key. This enables us to lookup | |
2883 | * the process specific cfq io context when entered from the block layer. | |
2884 | * Also adds the cic to a per-cfqd list, used when this queue is removed. | |
2885 | */ | |
febffd61 JA |
2886 | static int cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc, |
2887 | struct cfq_io_context *cic, gfp_t gfp_mask) | |
e2d74ac0 | 2888 | { |
0261d688 | 2889 | unsigned long flags; |
4ac845a2 | 2890 | int ret; |
e2d74ac0 | 2891 | |
4ac845a2 JA |
2892 | ret = radix_tree_preload(gfp_mask); |
2893 | if (!ret) { | |
2894 | cic->ioc = ioc; | |
2895 | cic->key = cfqd; | |
e2d74ac0 | 2896 | |
4ac845a2 JA |
2897 | spin_lock_irqsave(&ioc->lock, flags); |
2898 | ret = radix_tree_insert(&ioc->radix_root, | |
2899 | (unsigned long) cfqd, cic); | |
ffc4e759 JA |
2900 | if (!ret) |
2901 | hlist_add_head_rcu(&cic->cic_list, &ioc->cic_list); | |
4ac845a2 | 2902 | spin_unlock_irqrestore(&ioc->lock, flags); |
e2d74ac0 | 2903 | |
4ac845a2 JA |
2904 | radix_tree_preload_end(); |
2905 | ||
2906 | if (!ret) { | |
2907 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
2908 | list_add(&cic->queue_list, &cfqd->cic_list); | |
2909 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
2910 | } | |
e2d74ac0 JA |
2911 | } |
2912 | ||
4ac845a2 JA |
2913 | if (ret) |
2914 | printk(KERN_ERR "cfq: cic link failed!\n"); | |
fc46379d | 2915 | |
4ac845a2 | 2916 | return ret; |
e2d74ac0 JA |
2917 | } |
2918 | ||
1da177e4 LT |
2919 | /* |
2920 | * Setup general io context and cfq io context. There can be several cfq | |
2921 | * io contexts per general io context, if this process is doing io to more | |
e2d74ac0 | 2922 | * than one device managed by cfq. |
1da177e4 LT |
2923 | */ |
2924 | static struct cfq_io_context * | |
e2d74ac0 | 2925 | cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
1da177e4 | 2926 | { |
22e2c507 | 2927 | struct io_context *ioc = NULL; |
1da177e4 | 2928 | struct cfq_io_context *cic; |
1da177e4 | 2929 | |
22e2c507 | 2930 | might_sleep_if(gfp_mask & __GFP_WAIT); |
1da177e4 | 2931 | |
b5deef90 | 2932 | ioc = get_io_context(gfp_mask, cfqd->queue->node); |
1da177e4 LT |
2933 | if (!ioc) |
2934 | return NULL; | |
2935 | ||
4ac845a2 | 2936 | cic = cfq_cic_lookup(cfqd, ioc); |
e2d74ac0 JA |
2937 | if (cic) |
2938 | goto out; | |
1da177e4 | 2939 | |
e2d74ac0 JA |
2940 | cic = cfq_alloc_io_context(cfqd, gfp_mask); |
2941 | if (cic == NULL) | |
2942 | goto err; | |
1da177e4 | 2943 | |
4ac845a2 JA |
2944 | if (cfq_cic_link(cfqd, ioc, cic, gfp_mask)) |
2945 | goto err_free; | |
2946 | ||
1da177e4 | 2947 | out: |
fc46379d JA |
2948 | smp_read_barrier_depends(); |
2949 | if (unlikely(ioc->ioprio_changed)) | |
2950 | cfq_ioc_set_ioprio(ioc); | |
2951 | ||
24610333 VG |
2952 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
2953 | if (unlikely(ioc->cgroup_changed)) | |
2954 | cfq_ioc_set_cgroup(ioc); | |
2955 | #endif | |
1da177e4 | 2956 | return cic; |
4ac845a2 JA |
2957 | err_free: |
2958 | cfq_cic_free(cic); | |
1da177e4 LT |
2959 | err: |
2960 | put_io_context(ioc); | |
2961 | return NULL; | |
2962 | } | |
2963 | ||
22e2c507 JA |
2964 | static void |
2965 | cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic) | |
1da177e4 | 2966 | { |
aaf1228d JA |
2967 | unsigned long elapsed = jiffies - cic->last_end_request; |
2968 | unsigned long ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle); | |
db3b5848 | 2969 | |
22e2c507 JA |
2970 | cic->ttime_samples = (7*cic->ttime_samples + 256) / 8; |
2971 | cic->ttime_total = (7*cic->ttime_total + 256*ttime) / 8; | |
2972 | cic->ttime_mean = (cic->ttime_total + 128) / cic->ttime_samples; | |
2973 | } | |
1da177e4 | 2974 | |
206dc69b | 2975 | static void |
b2c18e1e | 2976 | cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
6d048f53 | 2977 | struct request *rq) |
206dc69b JA |
2978 | { |
2979 | sector_t sdist; | |
2980 | u64 total; | |
2981 | ||
b2c18e1e | 2982 | if (!cfqq->last_request_pos) |
4d00aa47 | 2983 | sdist = 0; |
b2c18e1e JM |
2984 | else if (cfqq->last_request_pos < blk_rq_pos(rq)) |
2985 | sdist = blk_rq_pos(rq) - cfqq->last_request_pos; | |
206dc69b | 2986 | else |
b2c18e1e | 2987 | sdist = cfqq->last_request_pos - blk_rq_pos(rq); |
206dc69b JA |
2988 | |
2989 | /* | |
2990 | * Don't allow the seek distance to get too large from the | |
2991 | * odd fragment, pagein, etc | |
2992 | */ | |
b2c18e1e JM |
2993 | if (cfqq->seek_samples <= 60) /* second&third seek */ |
2994 | sdist = min(sdist, (cfqq->seek_mean * 4) + 2*1024*1024); | |
206dc69b | 2995 | else |
b2c18e1e | 2996 | sdist = min(sdist, (cfqq->seek_mean * 4) + 2*1024*64); |
206dc69b | 2997 | |
b2c18e1e JM |
2998 | cfqq->seek_samples = (7*cfqq->seek_samples + 256) / 8; |
2999 | cfqq->seek_total = (7*cfqq->seek_total + (u64)256*sdist) / 8; | |
3000 | total = cfqq->seek_total + (cfqq->seek_samples/2); | |
3001 | do_div(total, cfqq->seek_samples); | |
3002 | cfqq->seek_mean = (sector_t)total; | |
e6c5bc73 JM |
3003 | |
3004 | /* | |
3005 | * If this cfqq is shared between multiple processes, check to | |
3006 | * make sure that those processes are still issuing I/Os within | |
3007 | * the mean seek distance. If not, it may be time to break the | |
3008 | * queues apart again. | |
3009 | */ | |
3010 | if (cfq_cfqq_coop(cfqq)) { | |
3011 | if (CFQQ_SEEKY(cfqq) && !cfqq->seeky_start) | |
3012 | cfqq->seeky_start = jiffies; | |
3013 | else if (!CFQQ_SEEKY(cfqq)) | |
3014 | cfqq->seeky_start = 0; | |
3015 | } | |
206dc69b | 3016 | } |
1da177e4 | 3017 | |
22e2c507 JA |
3018 | /* |
3019 | * Disable idle window if the process thinks too long or seeks so much that | |
3020 | * it doesn't matter | |
3021 | */ | |
3022 | static void | |
3023 | cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
3024 | struct cfq_io_context *cic) | |
3025 | { | |
7b679138 | 3026 | int old_idle, enable_idle; |
1be92f2f | 3027 | |
0871714e JA |
3028 | /* |
3029 | * Don't idle for async or idle io prio class | |
3030 | */ | |
3031 | if (!cfq_cfqq_sync(cfqq) || cfq_class_idle(cfqq)) | |
1be92f2f JA |
3032 | return; |
3033 | ||
c265a7f4 | 3034 | enable_idle = old_idle = cfq_cfqq_idle_window(cfqq); |
1da177e4 | 3035 | |
76280aff CZ |
3036 | if (cfqq->queued[0] + cfqq->queued[1] >= 4) |
3037 | cfq_mark_cfqq_deep(cfqq); | |
3038 | ||
66dac98e | 3039 | if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle || |
76280aff CZ |
3040 | (!cfq_cfqq_deep(cfqq) && sample_valid(cfqq->seek_samples) |
3041 | && CFQQ_SEEKY(cfqq))) | |
22e2c507 JA |
3042 | enable_idle = 0; |
3043 | else if (sample_valid(cic->ttime_samples)) { | |
718eee05 | 3044 | if (cic->ttime_mean > cfqd->cfq_slice_idle) |
22e2c507 JA |
3045 | enable_idle = 0; |
3046 | else | |
3047 | enable_idle = 1; | |
1da177e4 LT |
3048 | } |
3049 | ||
7b679138 JA |
3050 | if (old_idle != enable_idle) { |
3051 | cfq_log_cfqq(cfqd, cfqq, "idle=%d", enable_idle); | |
3052 | if (enable_idle) | |
3053 | cfq_mark_cfqq_idle_window(cfqq); | |
3054 | else | |
3055 | cfq_clear_cfqq_idle_window(cfqq); | |
3056 | } | |
22e2c507 | 3057 | } |
1da177e4 | 3058 | |
22e2c507 JA |
3059 | /* |
3060 | * Check if new_cfqq should preempt the currently active queue. Return 0 for | |
3061 | * no or if we aren't sure, a 1 will cause a preempt. | |
3062 | */ | |
a6151c3a | 3063 | static bool |
22e2c507 | 3064 | cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, |
5e705374 | 3065 | struct request *rq) |
22e2c507 | 3066 | { |
6d048f53 | 3067 | struct cfq_queue *cfqq; |
22e2c507 | 3068 | |
6d048f53 JA |
3069 | cfqq = cfqd->active_queue; |
3070 | if (!cfqq) | |
a6151c3a | 3071 | return false; |
22e2c507 | 3072 | |
6d048f53 | 3073 | if (cfq_class_idle(new_cfqq)) |
a6151c3a | 3074 | return false; |
22e2c507 JA |
3075 | |
3076 | if (cfq_class_idle(cfqq)) | |
a6151c3a | 3077 | return true; |
1e3335de | 3078 | |
875feb63 DS |
3079 | /* |
3080 | * Don't allow a non-RT request to preempt an ongoing RT cfqq timeslice. | |
3081 | */ | |
3082 | if (cfq_class_rt(cfqq) && !cfq_class_rt(new_cfqq)) | |
3083 | return false; | |
3084 | ||
374f84ac JA |
3085 | /* |
3086 | * if the new request is sync, but the currently running queue is | |
3087 | * not, let the sync request have priority. | |
3088 | */ | |
5e705374 | 3089 | if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq)) |
a6151c3a | 3090 | return true; |
1e3335de | 3091 | |
8682e1f1 VG |
3092 | if (new_cfqq->cfqg != cfqq->cfqg) |
3093 | return false; | |
3094 | ||
3095 | if (cfq_slice_used(cfqq)) | |
3096 | return true; | |
3097 | ||
3098 | /* Allow preemption only if we are idling on sync-noidle tree */ | |
3099 | if (cfqd->serving_type == SYNC_NOIDLE_WORKLOAD && | |
3100 | cfqq_type(new_cfqq) == SYNC_NOIDLE_WORKLOAD && | |
3101 | new_cfqq->service_tree->count == 2 && | |
3102 | RB_EMPTY_ROOT(&cfqq->sort_list)) | |
3103 | return true; | |
3104 | ||
374f84ac JA |
3105 | /* |
3106 | * So both queues are sync. Let the new request get disk time if | |
3107 | * it's a metadata request and the current queue is doing regular IO. | |
3108 | */ | |
3109 | if (rq_is_meta(rq) && !cfqq->meta_pending) | |
e6ec4fe2 | 3110 | return true; |
22e2c507 | 3111 | |
3a9a3f6c DS |
3112 | /* |
3113 | * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice. | |
3114 | */ | |
3115 | if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq)) | |
a6151c3a | 3116 | return true; |
3a9a3f6c | 3117 | |
1e3335de | 3118 | if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq)) |
a6151c3a | 3119 | return false; |
1e3335de JA |
3120 | |
3121 | /* | |
3122 | * if this request is as-good as one we would expect from the | |
3123 | * current cfqq, let it preempt | |
3124 | */ | |
2f7a2d89 | 3125 | if (cfq_rq_close(cfqd, cfqq, rq, true)) |
a6151c3a | 3126 | return true; |
1e3335de | 3127 | |
a6151c3a | 3128 | return false; |
22e2c507 JA |
3129 | } |
3130 | ||
3131 | /* | |
3132 | * cfqq preempts the active queue. if we allowed preempt with no slice left, | |
3133 | * let it have half of its nominal slice. | |
3134 | */ | |
3135 | static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
3136 | { | |
7b679138 | 3137 | cfq_log_cfqq(cfqd, cfqq, "preempt"); |
6084cdda | 3138 | cfq_slice_expired(cfqd, 1); |
22e2c507 | 3139 | |
bf572256 JA |
3140 | /* |
3141 | * Put the new queue at the front of the of the current list, | |
3142 | * so we know that it will be selected next. | |
3143 | */ | |
3144 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); | |
edd75ffd JA |
3145 | |
3146 | cfq_service_tree_add(cfqd, cfqq, 1); | |
bf572256 | 3147 | |
44f7c160 JA |
3148 | cfqq->slice_end = 0; |
3149 | cfq_mark_cfqq_slice_new(cfqq); | |
22e2c507 JA |
3150 | } |
3151 | ||
22e2c507 | 3152 | /* |
5e705374 | 3153 | * Called when a new fs request (rq) is added (to cfqq). Check if there's |
22e2c507 JA |
3154 | * something we should do about it |
3155 | */ | |
3156 | static void | |
5e705374 JA |
3157 | cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
3158 | struct request *rq) | |
22e2c507 | 3159 | { |
5e705374 | 3160 | struct cfq_io_context *cic = RQ_CIC(rq); |
12e9fddd | 3161 | |
45333d5a | 3162 | cfqd->rq_queued++; |
374f84ac JA |
3163 | if (rq_is_meta(rq)) |
3164 | cfqq->meta_pending++; | |
3165 | ||
9c2c38a1 | 3166 | cfq_update_io_thinktime(cfqd, cic); |
b2c18e1e | 3167 | cfq_update_io_seektime(cfqd, cfqq, rq); |
9c2c38a1 JA |
3168 | cfq_update_idle_window(cfqd, cfqq, cic); |
3169 | ||
b2c18e1e | 3170 | cfqq->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq); |
22e2c507 JA |
3171 | |
3172 | if (cfqq == cfqd->active_queue) { | |
3173 | /* | |
b029195d JA |
3174 | * Remember that we saw a request from this process, but |
3175 | * don't start queuing just yet. Otherwise we risk seeing lots | |
3176 | * of tiny requests, because we disrupt the normal plugging | |
d6ceb25e JA |
3177 | * and merging. If the request is already larger than a single |
3178 | * page, let it rip immediately. For that case we assume that | |
2d870722 JA |
3179 | * merging is already done. Ditto for a busy system that |
3180 | * has other work pending, don't risk delaying until the | |
3181 | * idle timer unplug to continue working. | |
22e2c507 | 3182 | */ |
d6ceb25e | 3183 | if (cfq_cfqq_wait_request(cfqq)) { |
2d870722 JA |
3184 | if (blk_rq_bytes(rq) > PAGE_CACHE_SIZE || |
3185 | cfqd->busy_queues > 1) { | |
d6ceb25e | 3186 | del_timer(&cfqd->idle_slice_timer); |
554554f6 | 3187 | cfq_clear_cfqq_wait_request(cfqq); |
bf791937 VG |
3188 | __blk_run_queue(cfqd->queue); |
3189 | } else | |
3190 | cfq_mark_cfqq_must_dispatch(cfqq); | |
d6ceb25e | 3191 | } |
5e705374 | 3192 | } else if (cfq_should_preempt(cfqd, cfqq, rq)) { |
22e2c507 JA |
3193 | /* |
3194 | * not the active queue - expire current slice if it is | |
3195 | * idle and has expired it's mean thinktime or this new queue | |
3a9a3f6c DS |
3196 | * has some old slice time left and is of higher priority or |
3197 | * this new queue is RT and the current one is BE | |
22e2c507 JA |
3198 | */ |
3199 | cfq_preempt_queue(cfqd, cfqq); | |
a7f55792 | 3200 | __blk_run_queue(cfqd->queue); |
22e2c507 | 3201 | } |
1da177e4 LT |
3202 | } |
3203 | ||
165125e1 | 3204 | static void cfq_insert_request(struct request_queue *q, struct request *rq) |
1da177e4 | 3205 | { |
b4878f24 | 3206 | struct cfq_data *cfqd = q->elevator->elevator_data; |
5e705374 | 3207 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 | 3208 | |
7b679138 | 3209 | cfq_log_cfqq(cfqd, cfqq, "insert_request"); |
fd0928df | 3210 | cfq_init_prio_data(cfqq, RQ_CIC(rq)->ioc); |
1da177e4 | 3211 | |
30996f40 | 3212 | rq_set_fifo_time(rq, jiffies + cfqd->cfq_fifo_expire[rq_is_sync(rq)]); |
22e2c507 | 3213 | list_add_tail(&rq->queuelist, &cfqq->fifo); |
aa6f6a3d | 3214 | cfq_add_rq_rb(rq); |
22e2c507 | 3215 | |
5e705374 | 3216 | cfq_rq_enqueued(cfqd, cfqq, rq); |
1da177e4 LT |
3217 | } |
3218 | ||
45333d5a AC |
3219 | /* |
3220 | * Update hw_tag based on peak queue depth over 50 samples under | |
3221 | * sufficient load. | |
3222 | */ | |
3223 | static void cfq_update_hw_tag(struct cfq_data *cfqd) | |
3224 | { | |
1a1238a7 SL |
3225 | struct cfq_queue *cfqq = cfqd->active_queue; |
3226 | ||
e459dd08 CZ |
3227 | if (rq_in_driver(cfqd) > cfqd->hw_tag_est_depth) |
3228 | cfqd->hw_tag_est_depth = rq_in_driver(cfqd); | |
3229 | ||
3230 | if (cfqd->hw_tag == 1) | |
3231 | return; | |
45333d5a AC |
3232 | |
3233 | if (cfqd->rq_queued <= CFQ_HW_QUEUE_MIN && | |
5ad531db | 3234 | rq_in_driver(cfqd) <= CFQ_HW_QUEUE_MIN) |
45333d5a AC |
3235 | return; |
3236 | ||
1a1238a7 SL |
3237 | /* |
3238 | * If active queue hasn't enough requests and can idle, cfq might not | |
3239 | * dispatch sufficient requests to hardware. Don't zero hw_tag in this | |
3240 | * case | |
3241 | */ | |
3242 | if (cfqq && cfq_cfqq_idle_window(cfqq) && | |
3243 | cfqq->dispatched + cfqq->queued[0] + cfqq->queued[1] < | |
3244 | CFQ_HW_QUEUE_MIN && rq_in_driver(cfqd) < CFQ_HW_QUEUE_MIN) | |
3245 | return; | |
3246 | ||
45333d5a AC |
3247 | if (cfqd->hw_tag_samples++ < 50) |
3248 | return; | |
3249 | ||
e459dd08 | 3250 | if (cfqd->hw_tag_est_depth >= CFQ_HW_QUEUE_MIN) |
45333d5a AC |
3251 | cfqd->hw_tag = 1; |
3252 | else | |
3253 | cfqd->hw_tag = 0; | |
45333d5a AC |
3254 | } |
3255 | ||
7667aa06 VG |
3256 | static bool cfq_should_wait_busy(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
3257 | { | |
3258 | struct cfq_io_context *cic = cfqd->active_cic; | |
3259 | ||
3260 | /* If there are other queues in the group, don't wait */ | |
3261 | if (cfqq->cfqg->nr_cfqq > 1) | |
3262 | return false; | |
3263 | ||
3264 | if (cfq_slice_used(cfqq)) | |
3265 | return true; | |
3266 | ||
3267 | /* if slice left is less than think time, wait busy */ | |
3268 | if (cic && sample_valid(cic->ttime_samples) | |
3269 | && (cfqq->slice_end - jiffies < cic->ttime_mean)) | |
3270 | return true; | |
3271 | ||
3272 | /* | |
3273 | * If think times is less than a jiffy than ttime_mean=0 and above | |
3274 | * will not be true. It might happen that slice has not expired yet | |
3275 | * but will expire soon (4-5 ns) during select_queue(). To cover the | |
3276 | * case where think time is less than a jiffy, mark the queue wait | |
3277 | * busy if only 1 jiffy is left in the slice. | |
3278 | */ | |
3279 | if (cfqq->slice_end - jiffies == 1) | |
3280 | return true; | |
3281 | ||
3282 | return false; | |
3283 | } | |
3284 | ||
165125e1 | 3285 | static void cfq_completed_request(struct request_queue *q, struct request *rq) |
1da177e4 | 3286 | { |
5e705374 | 3287 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
b4878f24 | 3288 | struct cfq_data *cfqd = cfqq->cfqd; |
5380a101 | 3289 | const int sync = rq_is_sync(rq); |
b4878f24 | 3290 | unsigned long now; |
1da177e4 | 3291 | |
b4878f24 | 3292 | now = jiffies; |
2868ef7b | 3293 | cfq_log_cfqq(cfqd, cfqq, "complete rqnoidle %d", !!rq_noidle(rq)); |
1da177e4 | 3294 | |
45333d5a AC |
3295 | cfq_update_hw_tag(cfqd); |
3296 | ||
5ad531db | 3297 | WARN_ON(!cfqd->rq_in_driver[sync]); |
6d048f53 | 3298 | WARN_ON(!cfqq->dispatched); |
5ad531db | 3299 | cfqd->rq_in_driver[sync]--; |
6d048f53 | 3300 | cfqq->dispatched--; |
1da177e4 | 3301 | |
3ed9a296 JA |
3302 | if (cfq_cfqq_sync(cfqq)) |
3303 | cfqd->sync_flight--; | |
3304 | ||
365722bb | 3305 | if (sync) { |
5e705374 | 3306 | RQ_CIC(rq)->last_end_request = now; |
573412b2 CZ |
3307 | if (!time_after(rq->start_time + cfqd->cfq_fifo_expire[1], now)) |
3308 | cfqd->last_delayed_sync = now; | |
365722bb | 3309 | } |
caaa5f9f JA |
3310 | |
3311 | /* | |
3312 | * If this is the active queue, check if it needs to be expired, | |
3313 | * or if we want to idle in case it has no pending requests. | |
3314 | */ | |
3315 | if (cfqd->active_queue == cfqq) { | |
a36e71f9 JA |
3316 | const bool cfqq_empty = RB_EMPTY_ROOT(&cfqq->sort_list); |
3317 | ||
44f7c160 JA |
3318 | if (cfq_cfqq_slice_new(cfqq)) { |
3319 | cfq_set_prio_slice(cfqd, cfqq); | |
3320 | cfq_clear_cfqq_slice_new(cfqq); | |
3321 | } | |
f75edf2d VG |
3322 | |
3323 | /* | |
7667aa06 VG |
3324 | * Should we wait for next request to come in before we expire |
3325 | * the queue. | |
f75edf2d | 3326 | */ |
7667aa06 | 3327 | if (cfq_should_wait_busy(cfqd, cfqq)) { |
f75edf2d VG |
3328 | cfqq->slice_end = jiffies + cfqd->cfq_slice_idle; |
3329 | cfq_mark_cfqq_wait_busy(cfqq); | |
3330 | } | |
3331 | ||
a36e71f9 | 3332 | /* |
8e550632 CZ |
3333 | * Idling is not enabled on: |
3334 | * - expired queues | |
3335 | * - idle-priority queues | |
3336 | * - async queues | |
3337 | * - queues with still some requests queued | |
3338 | * - when there is a close cooperator | |
a36e71f9 | 3339 | */ |
0871714e | 3340 | if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq)) |
6084cdda | 3341 | cfq_slice_expired(cfqd, 1); |
8e550632 CZ |
3342 | else if (sync && cfqq_empty && |
3343 | !cfq_close_cooperator(cfqd, cfqq)) { | |
3344 | cfqd->noidle_tree_requires_idle |= !rq_noidle(rq); | |
3345 | /* | |
3346 | * Idling is enabled for SYNC_WORKLOAD. | |
3347 | * SYNC_NOIDLE_WORKLOAD idles at the end of the tree | |
3348 | * only if we processed at least one !rq_noidle request | |
3349 | */ | |
3350 | if (cfqd->serving_type == SYNC_WORKLOAD | |
c04645e5 VG |
3351 | || cfqd->noidle_tree_requires_idle |
3352 | || cfqq->cfqg->nr_cfqq == 1) | |
8e550632 CZ |
3353 | cfq_arm_slice_timer(cfqd); |
3354 | } | |
caaa5f9f | 3355 | } |
6d048f53 | 3356 | |
5ad531db | 3357 | if (!rq_in_driver(cfqd)) |
23e018a1 | 3358 | cfq_schedule_dispatch(cfqd); |
1da177e4 LT |
3359 | } |
3360 | ||
22e2c507 JA |
3361 | /* |
3362 | * we temporarily boost lower priority queues if they are holding fs exclusive | |
3363 | * resources. they are boosted to normal prio (CLASS_BE/4) | |
3364 | */ | |
3365 | static void cfq_prio_boost(struct cfq_queue *cfqq) | |
1da177e4 | 3366 | { |
22e2c507 JA |
3367 | if (has_fs_excl()) { |
3368 | /* | |
3369 | * boost idle prio on transactions that would lock out other | |
3370 | * users of the filesystem | |
3371 | */ | |
3372 | if (cfq_class_idle(cfqq)) | |
3373 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
3374 | if (cfqq->ioprio > IOPRIO_NORM) | |
3375 | cfqq->ioprio = IOPRIO_NORM; | |
3376 | } else { | |
3377 | /* | |
dddb7451 | 3378 | * unboost the queue (if needed) |
22e2c507 | 3379 | */ |
dddb7451 CZ |
3380 | cfqq->ioprio_class = cfqq->org_ioprio_class; |
3381 | cfqq->ioprio = cfqq->org_ioprio; | |
22e2c507 | 3382 | } |
22e2c507 | 3383 | } |
1da177e4 | 3384 | |
89850f7e | 3385 | static inline int __cfq_may_queue(struct cfq_queue *cfqq) |
22e2c507 | 3386 | { |
1b379d8d | 3387 | if (cfq_cfqq_wait_request(cfqq) && !cfq_cfqq_must_alloc_slice(cfqq)) { |
3b18152c | 3388 | cfq_mark_cfqq_must_alloc_slice(cfqq); |
22e2c507 | 3389 | return ELV_MQUEUE_MUST; |
3b18152c | 3390 | } |
1da177e4 | 3391 | |
22e2c507 | 3392 | return ELV_MQUEUE_MAY; |
22e2c507 JA |
3393 | } |
3394 | ||
165125e1 | 3395 | static int cfq_may_queue(struct request_queue *q, int rw) |
22e2c507 JA |
3396 | { |
3397 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
3398 | struct task_struct *tsk = current; | |
91fac317 | 3399 | struct cfq_io_context *cic; |
22e2c507 JA |
3400 | struct cfq_queue *cfqq; |
3401 | ||
3402 | /* | |
3403 | * don't force setup of a queue from here, as a call to may_queue | |
3404 | * does not necessarily imply that a request actually will be queued. | |
3405 | * so just lookup a possibly existing queue, or return 'may queue' | |
3406 | * if that fails | |
3407 | */ | |
4ac845a2 | 3408 | cic = cfq_cic_lookup(cfqd, tsk->io_context); |
91fac317 VT |
3409 | if (!cic) |
3410 | return ELV_MQUEUE_MAY; | |
3411 | ||
b0b78f81 | 3412 | cfqq = cic_to_cfqq(cic, rw_is_sync(rw)); |
22e2c507 | 3413 | if (cfqq) { |
fd0928df | 3414 | cfq_init_prio_data(cfqq, cic->ioc); |
22e2c507 JA |
3415 | cfq_prio_boost(cfqq); |
3416 | ||
89850f7e | 3417 | return __cfq_may_queue(cfqq); |
22e2c507 JA |
3418 | } |
3419 | ||
3420 | return ELV_MQUEUE_MAY; | |
1da177e4 LT |
3421 | } |
3422 | ||
1da177e4 LT |
3423 | /* |
3424 | * queue lock held here | |
3425 | */ | |
bb37b94c | 3426 | static void cfq_put_request(struct request *rq) |
1da177e4 | 3427 | { |
5e705374 | 3428 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
1da177e4 | 3429 | |
5e705374 | 3430 | if (cfqq) { |
22e2c507 | 3431 | const int rw = rq_data_dir(rq); |
1da177e4 | 3432 | |
22e2c507 JA |
3433 | BUG_ON(!cfqq->allocated[rw]); |
3434 | cfqq->allocated[rw]--; | |
1da177e4 | 3435 | |
5e705374 | 3436 | put_io_context(RQ_CIC(rq)->ioc); |
1da177e4 | 3437 | |
1da177e4 | 3438 | rq->elevator_private = NULL; |
5e705374 | 3439 | rq->elevator_private2 = NULL; |
1da177e4 | 3440 | |
1da177e4 LT |
3441 | cfq_put_queue(cfqq); |
3442 | } | |
3443 | } | |
3444 | ||
df5fe3e8 JM |
3445 | static struct cfq_queue * |
3446 | cfq_merge_cfqqs(struct cfq_data *cfqd, struct cfq_io_context *cic, | |
3447 | struct cfq_queue *cfqq) | |
3448 | { | |
3449 | cfq_log_cfqq(cfqd, cfqq, "merging with queue %p", cfqq->new_cfqq); | |
3450 | cic_set_cfqq(cic, cfqq->new_cfqq, 1); | |
b3b6d040 | 3451 | cfq_mark_cfqq_coop(cfqq->new_cfqq); |
df5fe3e8 JM |
3452 | cfq_put_queue(cfqq); |
3453 | return cic_to_cfqq(cic, 1); | |
3454 | } | |
3455 | ||
e6c5bc73 JM |
3456 | static int should_split_cfqq(struct cfq_queue *cfqq) |
3457 | { | |
3458 | if (cfqq->seeky_start && | |
3459 | time_after(jiffies, cfqq->seeky_start + CFQQ_COOP_TOUT)) | |
3460 | return 1; | |
3461 | return 0; | |
3462 | } | |
3463 | ||
3464 | /* | |
3465 | * Returns NULL if a new cfqq should be allocated, or the old cfqq if this | |
3466 | * was the last process referring to said cfqq. | |
3467 | */ | |
3468 | static struct cfq_queue * | |
3469 | split_cfqq(struct cfq_io_context *cic, struct cfq_queue *cfqq) | |
3470 | { | |
3471 | if (cfqq_process_refs(cfqq) == 1) { | |
3472 | cfqq->seeky_start = 0; | |
3473 | cfqq->pid = current->pid; | |
3474 | cfq_clear_cfqq_coop(cfqq); | |
3475 | return cfqq; | |
3476 | } | |
3477 | ||
3478 | cic_set_cfqq(cic, NULL, 1); | |
3479 | cfq_put_queue(cfqq); | |
3480 | return NULL; | |
3481 | } | |
1da177e4 | 3482 | /* |
22e2c507 | 3483 | * Allocate cfq data structures associated with this request. |
1da177e4 | 3484 | */ |
22e2c507 | 3485 | static int |
165125e1 | 3486 | cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask) |
1da177e4 LT |
3487 | { |
3488 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
3489 | struct cfq_io_context *cic; | |
3490 | const int rw = rq_data_dir(rq); | |
a6151c3a | 3491 | const bool is_sync = rq_is_sync(rq); |
22e2c507 | 3492 | struct cfq_queue *cfqq; |
1da177e4 LT |
3493 | unsigned long flags; |
3494 | ||
3495 | might_sleep_if(gfp_mask & __GFP_WAIT); | |
3496 | ||
e2d74ac0 | 3497 | cic = cfq_get_io_context(cfqd, gfp_mask); |
22e2c507 | 3498 | |
1da177e4 LT |
3499 | spin_lock_irqsave(q->queue_lock, flags); |
3500 | ||
22e2c507 JA |
3501 | if (!cic) |
3502 | goto queue_fail; | |
3503 | ||
e6c5bc73 | 3504 | new_queue: |
91fac317 | 3505 | cfqq = cic_to_cfqq(cic, is_sync); |
32f2e807 | 3506 | if (!cfqq || cfqq == &cfqd->oom_cfqq) { |
fd0928df | 3507 | cfqq = cfq_get_queue(cfqd, is_sync, cic->ioc, gfp_mask); |
91fac317 | 3508 | cic_set_cfqq(cic, cfqq, is_sync); |
df5fe3e8 | 3509 | } else { |
e6c5bc73 JM |
3510 | /* |
3511 | * If the queue was seeky for too long, break it apart. | |
3512 | */ | |
3513 | if (cfq_cfqq_coop(cfqq) && should_split_cfqq(cfqq)) { | |
3514 | cfq_log_cfqq(cfqd, cfqq, "breaking apart cfqq"); | |
3515 | cfqq = split_cfqq(cic, cfqq); | |
3516 | if (!cfqq) | |
3517 | goto new_queue; | |
3518 | } | |
3519 | ||
df5fe3e8 JM |
3520 | /* |
3521 | * Check to see if this queue is scheduled to merge with | |
3522 | * another, closely cooperating queue. The merging of | |
3523 | * queues happens here as it must be done in process context. | |
3524 | * The reference on new_cfqq was taken in merge_cfqqs. | |
3525 | */ | |
3526 | if (cfqq->new_cfqq) | |
3527 | cfqq = cfq_merge_cfqqs(cfqd, cic, cfqq); | |
91fac317 | 3528 | } |
1da177e4 LT |
3529 | |
3530 | cfqq->allocated[rw]++; | |
22e2c507 | 3531 | atomic_inc(&cfqq->ref); |
1da177e4 | 3532 | |
5e705374 | 3533 | spin_unlock_irqrestore(q->queue_lock, flags); |
3b18152c | 3534 | |
5e705374 JA |
3535 | rq->elevator_private = cic; |
3536 | rq->elevator_private2 = cfqq; | |
3537 | return 0; | |
1da177e4 | 3538 | |
22e2c507 JA |
3539 | queue_fail: |
3540 | if (cic) | |
3541 | put_io_context(cic->ioc); | |
89850f7e | 3542 | |
23e018a1 | 3543 | cfq_schedule_dispatch(cfqd); |
1da177e4 | 3544 | spin_unlock_irqrestore(q->queue_lock, flags); |
7b679138 | 3545 | cfq_log(cfqd, "set_request fail"); |
1da177e4 LT |
3546 | return 1; |
3547 | } | |
3548 | ||
65f27f38 | 3549 | static void cfq_kick_queue(struct work_struct *work) |
22e2c507 | 3550 | { |
65f27f38 | 3551 | struct cfq_data *cfqd = |
23e018a1 | 3552 | container_of(work, struct cfq_data, unplug_work); |
165125e1 | 3553 | struct request_queue *q = cfqd->queue; |
22e2c507 | 3554 | |
40bb54d1 | 3555 | spin_lock_irq(q->queue_lock); |
a7f55792 | 3556 | __blk_run_queue(cfqd->queue); |
40bb54d1 | 3557 | spin_unlock_irq(q->queue_lock); |
22e2c507 JA |
3558 | } |
3559 | ||
3560 | /* | |
3561 | * Timer running if the active_queue is currently idling inside its time slice | |
3562 | */ | |
3563 | static void cfq_idle_slice_timer(unsigned long data) | |
3564 | { | |
3565 | struct cfq_data *cfqd = (struct cfq_data *) data; | |
3566 | struct cfq_queue *cfqq; | |
3567 | unsigned long flags; | |
3c6bd2f8 | 3568 | int timed_out = 1; |
22e2c507 | 3569 | |
7b679138 JA |
3570 | cfq_log(cfqd, "idle timer fired"); |
3571 | ||
22e2c507 JA |
3572 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); |
3573 | ||
fe094d98 JA |
3574 | cfqq = cfqd->active_queue; |
3575 | if (cfqq) { | |
3c6bd2f8 JA |
3576 | timed_out = 0; |
3577 | ||
b029195d JA |
3578 | /* |
3579 | * We saw a request before the queue expired, let it through | |
3580 | */ | |
3581 | if (cfq_cfqq_must_dispatch(cfqq)) | |
3582 | goto out_kick; | |
3583 | ||
22e2c507 JA |
3584 | /* |
3585 | * expired | |
3586 | */ | |
44f7c160 | 3587 | if (cfq_slice_used(cfqq)) |
22e2c507 JA |
3588 | goto expire; |
3589 | ||
3590 | /* | |
3591 | * only expire and reinvoke request handler, if there are | |
3592 | * other queues with pending requests | |
3593 | */ | |
caaa5f9f | 3594 | if (!cfqd->busy_queues) |
22e2c507 | 3595 | goto out_cont; |
22e2c507 JA |
3596 | |
3597 | /* | |
3598 | * not expired and it has a request pending, let it dispatch | |
3599 | */ | |
75e50984 | 3600 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
22e2c507 | 3601 | goto out_kick; |
76280aff CZ |
3602 | |
3603 | /* | |
3604 | * Queue depth flag is reset only when the idle didn't succeed | |
3605 | */ | |
3606 | cfq_clear_cfqq_deep(cfqq); | |
22e2c507 JA |
3607 | } |
3608 | expire: | |
6084cdda | 3609 | cfq_slice_expired(cfqd, timed_out); |
22e2c507 | 3610 | out_kick: |
23e018a1 | 3611 | cfq_schedule_dispatch(cfqd); |
22e2c507 JA |
3612 | out_cont: |
3613 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
3614 | } | |
3615 | ||
3b18152c JA |
3616 | static void cfq_shutdown_timer_wq(struct cfq_data *cfqd) |
3617 | { | |
3618 | del_timer_sync(&cfqd->idle_slice_timer); | |
23e018a1 | 3619 | cancel_work_sync(&cfqd->unplug_work); |
3b18152c | 3620 | } |
22e2c507 | 3621 | |
c2dea2d1 VT |
3622 | static void cfq_put_async_queues(struct cfq_data *cfqd) |
3623 | { | |
3624 | int i; | |
3625 | ||
3626 | for (i = 0; i < IOPRIO_BE_NR; i++) { | |
3627 | if (cfqd->async_cfqq[0][i]) | |
3628 | cfq_put_queue(cfqd->async_cfqq[0][i]); | |
3629 | if (cfqd->async_cfqq[1][i]) | |
3630 | cfq_put_queue(cfqd->async_cfqq[1][i]); | |
c2dea2d1 | 3631 | } |
2389d1ef ON |
3632 | |
3633 | if (cfqd->async_idle_cfqq) | |
3634 | cfq_put_queue(cfqd->async_idle_cfqq); | |
c2dea2d1 VT |
3635 | } |
3636 | ||
bb729bc9 JA |
3637 | static void cfq_cfqd_free(struct rcu_head *head) |
3638 | { | |
3639 | kfree(container_of(head, struct cfq_data, rcu)); | |
3640 | } | |
3641 | ||
b374d18a | 3642 | static void cfq_exit_queue(struct elevator_queue *e) |
1da177e4 | 3643 | { |
22e2c507 | 3644 | struct cfq_data *cfqd = e->elevator_data; |
165125e1 | 3645 | struct request_queue *q = cfqd->queue; |
22e2c507 | 3646 | |
3b18152c | 3647 | cfq_shutdown_timer_wq(cfqd); |
e2d74ac0 | 3648 | |
d9ff4187 | 3649 | spin_lock_irq(q->queue_lock); |
e2d74ac0 | 3650 | |
d9ff4187 | 3651 | if (cfqd->active_queue) |
6084cdda | 3652 | __cfq_slice_expired(cfqd, cfqd->active_queue, 0); |
e2d74ac0 JA |
3653 | |
3654 | while (!list_empty(&cfqd->cic_list)) { | |
d9ff4187 AV |
3655 | struct cfq_io_context *cic = list_entry(cfqd->cic_list.next, |
3656 | struct cfq_io_context, | |
3657 | queue_list); | |
89850f7e JA |
3658 | |
3659 | __cfq_exit_single_io_context(cfqd, cic); | |
d9ff4187 | 3660 | } |
e2d74ac0 | 3661 | |
c2dea2d1 | 3662 | cfq_put_async_queues(cfqd); |
b1c35769 VG |
3663 | cfq_release_cfq_groups(cfqd); |
3664 | blkiocg_del_blkio_group(&cfqd->root_group.blkg); | |
15c31be4 | 3665 | |
d9ff4187 | 3666 | spin_unlock_irq(q->queue_lock); |
a90d742e AV |
3667 | |
3668 | cfq_shutdown_timer_wq(cfqd); | |
3669 | ||
b1c35769 | 3670 | /* Wait for cfqg->blkg->key accessors to exit their grace periods. */ |
bb729bc9 | 3671 | call_rcu(&cfqd->rcu, cfq_cfqd_free); |
1da177e4 LT |
3672 | } |
3673 | ||
165125e1 | 3674 | static void *cfq_init_queue(struct request_queue *q) |
1da177e4 LT |
3675 | { |
3676 | struct cfq_data *cfqd; | |
718eee05 | 3677 | int i, j; |
cdb16e8f | 3678 | struct cfq_group *cfqg; |
615f0259 | 3679 | struct cfq_rb_root *st; |
1da177e4 | 3680 | |
94f6030c | 3681 | cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL | __GFP_ZERO, q->node); |
1da177e4 | 3682 | if (!cfqd) |
bc1c1169 | 3683 | return NULL; |
1da177e4 | 3684 | |
1fa8f6d6 VG |
3685 | /* Init root service tree */ |
3686 | cfqd->grp_service_tree = CFQ_RB_ROOT; | |
3687 | ||
cdb16e8f VG |
3688 | /* Init root group */ |
3689 | cfqg = &cfqd->root_group; | |
615f0259 VG |
3690 | for_each_cfqg_st(cfqg, i, j, st) |
3691 | *st = CFQ_RB_ROOT; | |
1fa8f6d6 | 3692 | RB_CLEAR_NODE(&cfqg->rb_node); |
26a2ac00 | 3693 | |
25bc6b07 VG |
3694 | /* Give preference to root group over other groups */ |
3695 | cfqg->weight = 2*BLKIO_WEIGHT_DEFAULT; | |
3696 | ||
25fb5169 | 3697 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
b1c35769 VG |
3698 | /* |
3699 | * Take a reference to root group which we never drop. This is just | |
3700 | * to make sure that cfq_put_cfqg() does not try to kfree root group | |
3701 | */ | |
3702 | atomic_set(&cfqg->ref, 1); | |
22084190 VG |
3703 | blkiocg_add_blkio_group(&blkio_root_cgroup, &cfqg->blkg, (void *)cfqd, |
3704 | 0); | |
25fb5169 | 3705 | #endif |
26a2ac00 JA |
3706 | /* |
3707 | * Not strictly needed (since RB_ROOT just clears the node and we | |
3708 | * zeroed cfqd on alloc), but better be safe in case someone decides | |
3709 | * to add magic to the rb code | |
3710 | */ | |
3711 | for (i = 0; i < CFQ_PRIO_LISTS; i++) | |
3712 | cfqd->prio_trees[i] = RB_ROOT; | |
3713 | ||
6118b70b JA |
3714 | /* |
3715 | * Our fallback cfqq if cfq_find_alloc_queue() runs into OOM issues. | |
3716 | * Grab a permanent reference to it, so that the normal code flow | |
3717 | * will not attempt to free it. | |
3718 | */ | |
3719 | cfq_init_cfqq(cfqd, &cfqd->oom_cfqq, 1, 0); | |
3720 | atomic_inc(&cfqd->oom_cfqq.ref); | |
cdb16e8f | 3721 | cfq_link_cfqq_cfqg(&cfqd->oom_cfqq, &cfqd->root_group); |
6118b70b | 3722 | |
d9ff4187 | 3723 | INIT_LIST_HEAD(&cfqd->cic_list); |
1da177e4 | 3724 | |
1da177e4 | 3725 | cfqd->queue = q; |
1da177e4 | 3726 | |
22e2c507 JA |
3727 | init_timer(&cfqd->idle_slice_timer); |
3728 | cfqd->idle_slice_timer.function = cfq_idle_slice_timer; | |
3729 | cfqd->idle_slice_timer.data = (unsigned long) cfqd; | |
3730 | ||
23e018a1 | 3731 | INIT_WORK(&cfqd->unplug_work, cfq_kick_queue); |
22e2c507 | 3732 | |
1da177e4 | 3733 | cfqd->cfq_quantum = cfq_quantum; |
22e2c507 JA |
3734 | cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; |
3735 | cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; | |
1da177e4 LT |
3736 | cfqd->cfq_back_max = cfq_back_max; |
3737 | cfqd->cfq_back_penalty = cfq_back_penalty; | |
22e2c507 JA |
3738 | cfqd->cfq_slice[0] = cfq_slice_async; |
3739 | cfqd->cfq_slice[1] = cfq_slice_sync; | |
3740 | cfqd->cfq_slice_async_rq = cfq_slice_async_rq; | |
3741 | cfqd->cfq_slice_idle = cfq_slice_idle; | |
963b72fc | 3742 | cfqd->cfq_latency = 1; |
ae30c286 | 3743 | cfqd->cfq_group_isolation = 0; |
e459dd08 | 3744 | cfqd->hw_tag = -1; |
edc71131 CZ |
3745 | /* |
3746 | * we optimistically start assuming sync ops weren't delayed in last | |
3747 | * second, in order to have larger depth for async operations. | |
3748 | */ | |
573412b2 | 3749 | cfqd->last_delayed_sync = jiffies - HZ; |
bb729bc9 | 3750 | INIT_RCU_HEAD(&cfqd->rcu); |
bc1c1169 | 3751 | return cfqd; |
1da177e4 LT |
3752 | } |
3753 | ||
3754 | static void cfq_slab_kill(void) | |
3755 | { | |
d6de8be7 JA |
3756 | /* |
3757 | * Caller already ensured that pending RCU callbacks are completed, | |
3758 | * so we should have no busy allocations at this point. | |
3759 | */ | |
1da177e4 LT |
3760 | if (cfq_pool) |
3761 | kmem_cache_destroy(cfq_pool); | |
3762 | if (cfq_ioc_pool) | |
3763 | kmem_cache_destroy(cfq_ioc_pool); | |
3764 | } | |
3765 | ||
3766 | static int __init cfq_slab_setup(void) | |
3767 | { | |
0a31bd5f | 3768 | cfq_pool = KMEM_CACHE(cfq_queue, 0); |
1da177e4 LT |
3769 | if (!cfq_pool) |
3770 | goto fail; | |
3771 | ||
34e6bbf2 | 3772 | cfq_ioc_pool = KMEM_CACHE(cfq_io_context, 0); |
1da177e4 LT |
3773 | if (!cfq_ioc_pool) |
3774 | goto fail; | |
3775 | ||
3776 | return 0; | |
3777 | fail: | |
3778 | cfq_slab_kill(); | |
3779 | return -ENOMEM; | |
3780 | } | |
3781 | ||
1da177e4 LT |
3782 | /* |
3783 | * sysfs parts below --> | |
3784 | */ | |
1da177e4 LT |
3785 | static ssize_t |
3786 | cfq_var_show(unsigned int var, char *page) | |
3787 | { | |
3788 | return sprintf(page, "%d\n", var); | |
3789 | } | |
3790 | ||
3791 | static ssize_t | |
3792 | cfq_var_store(unsigned int *var, const char *page, size_t count) | |
3793 | { | |
3794 | char *p = (char *) page; | |
3795 | ||
3796 | *var = simple_strtoul(p, &p, 10); | |
3797 | return count; | |
3798 | } | |
3799 | ||
1da177e4 | 3800 | #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ |
b374d18a | 3801 | static ssize_t __FUNC(struct elevator_queue *e, char *page) \ |
1da177e4 | 3802 | { \ |
3d1ab40f | 3803 | struct cfq_data *cfqd = e->elevator_data; \ |
1da177e4 LT |
3804 | unsigned int __data = __VAR; \ |
3805 | if (__CONV) \ | |
3806 | __data = jiffies_to_msecs(__data); \ | |
3807 | return cfq_var_show(__data, (page)); \ | |
3808 | } | |
3809 | SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); | |
22e2c507 JA |
3810 | SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1); |
3811 | SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1); | |
e572ec7e AV |
3812 | SHOW_FUNCTION(cfq_back_seek_max_show, cfqd->cfq_back_max, 0); |
3813 | SHOW_FUNCTION(cfq_back_seek_penalty_show, cfqd->cfq_back_penalty, 0); | |
22e2c507 JA |
3814 | SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1); |
3815 | SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1); | |
3816 | SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1); | |
3817 | SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0); | |
963b72fc | 3818 | SHOW_FUNCTION(cfq_low_latency_show, cfqd->cfq_latency, 0); |
ae30c286 | 3819 | SHOW_FUNCTION(cfq_group_isolation_show, cfqd->cfq_group_isolation, 0); |
1da177e4 LT |
3820 | #undef SHOW_FUNCTION |
3821 | ||
3822 | #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ | |
b374d18a | 3823 | static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \ |
1da177e4 | 3824 | { \ |
3d1ab40f | 3825 | struct cfq_data *cfqd = e->elevator_data; \ |
1da177e4 LT |
3826 | unsigned int __data; \ |
3827 | int ret = cfq_var_store(&__data, (page), count); \ | |
3828 | if (__data < (MIN)) \ | |
3829 | __data = (MIN); \ | |
3830 | else if (__data > (MAX)) \ | |
3831 | __data = (MAX); \ | |
3832 | if (__CONV) \ | |
3833 | *(__PTR) = msecs_to_jiffies(__data); \ | |
3834 | else \ | |
3835 | *(__PTR) = __data; \ | |
3836 | return ret; \ | |
3837 | } | |
3838 | STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); | |
fe094d98 JA |
3839 | STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, |
3840 | UINT_MAX, 1); | |
3841 | STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, | |
3842 | UINT_MAX, 1); | |
e572ec7e | 3843 | STORE_FUNCTION(cfq_back_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); |
fe094d98 JA |
3844 | STORE_FUNCTION(cfq_back_seek_penalty_store, &cfqd->cfq_back_penalty, 1, |
3845 | UINT_MAX, 0); | |
22e2c507 JA |
3846 | STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1); |
3847 | STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1); | |
3848 | STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1); | |
fe094d98 JA |
3849 | STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, |
3850 | UINT_MAX, 0); | |
963b72fc | 3851 | STORE_FUNCTION(cfq_low_latency_store, &cfqd->cfq_latency, 0, 1, 0); |
ae30c286 | 3852 | STORE_FUNCTION(cfq_group_isolation_store, &cfqd->cfq_group_isolation, 0, 1, 0); |
1da177e4 LT |
3853 | #undef STORE_FUNCTION |
3854 | ||
e572ec7e AV |
3855 | #define CFQ_ATTR(name) \ |
3856 | __ATTR(name, S_IRUGO|S_IWUSR, cfq_##name##_show, cfq_##name##_store) | |
3857 | ||
3858 | static struct elv_fs_entry cfq_attrs[] = { | |
3859 | CFQ_ATTR(quantum), | |
e572ec7e AV |
3860 | CFQ_ATTR(fifo_expire_sync), |
3861 | CFQ_ATTR(fifo_expire_async), | |
3862 | CFQ_ATTR(back_seek_max), | |
3863 | CFQ_ATTR(back_seek_penalty), | |
3864 | CFQ_ATTR(slice_sync), | |
3865 | CFQ_ATTR(slice_async), | |
3866 | CFQ_ATTR(slice_async_rq), | |
3867 | CFQ_ATTR(slice_idle), | |
963b72fc | 3868 | CFQ_ATTR(low_latency), |
ae30c286 | 3869 | CFQ_ATTR(group_isolation), |
e572ec7e | 3870 | __ATTR_NULL |
1da177e4 LT |
3871 | }; |
3872 | ||
1da177e4 LT |
3873 | static struct elevator_type iosched_cfq = { |
3874 | .ops = { | |
3875 | .elevator_merge_fn = cfq_merge, | |
3876 | .elevator_merged_fn = cfq_merged_request, | |
3877 | .elevator_merge_req_fn = cfq_merged_requests, | |
da775265 | 3878 | .elevator_allow_merge_fn = cfq_allow_merge, |
b4878f24 | 3879 | .elevator_dispatch_fn = cfq_dispatch_requests, |
1da177e4 | 3880 | .elevator_add_req_fn = cfq_insert_request, |
b4878f24 | 3881 | .elevator_activate_req_fn = cfq_activate_request, |
1da177e4 LT |
3882 | .elevator_deactivate_req_fn = cfq_deactivate_request, |
3883 | .elevator_queue_empty_fn = cfq_queue_empty, | |
3884 | .elevator_completed_req_fn = cfq_completed_request, | |
21183b07 JA |
3885 | .elevator_former_req_fn = elv_rb_former_request, |
3886 | .elevator_latter_req_fn = elv_rb_latter_request, | |
1da177e4 LT |
3887 | .elevator_set_req_fn = cfq_set_request, |
3888 | .elevator_put_req_fn = cfq_put_request, | |
3889 | .elevator_may_queue_fn = cfq_may_queue, | |
3890 | .elevator_init_fn = cfq_init_queue, | |
3891 | .elevator_exit_fn = cfq_exit_queue, | |
fc46379d | 3892 | .trim = cfq_free_io_context, |
1da177e4 | 3893 | }, |
3d1ab40f | 3894 | .elevator_attrs = cfq_attrs, |
1da177e4 LT |
3895 | .elevator_name = "cfq", |
3896 | .elevator_owner = THIS_MODULE, | |
3897 | }; | |
3898 | ||
3e252066 VG |
3899 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
3900 | static struct blkio_policy_type blkio_policy_cfq = { | |
3901 | .ops = { | |
3902 | .blkio_unlink_group_fn = cfq_unlink_blkio_group, | |
3903 | .blkio_update_group_weight_fn = cfq_update_blkio_group_weight, | |
3904 | }, | |
3905 | }; | |
3906 | #else | |
3907 | static struct blkio_policy_type blkio_policy_cfq; | |
3908 | #endif | |
3909 | ||
1da177e4 LT |
3910 | static int __init cfq_init(void) |
3911 | { | |
22e2c507 JA |
3912 | /* |
3913 | * could be 0 on HZ < 1000 setups | |
3914 | */ | |
3915 | if (!cfq_slice_async) | |
3916 | cfq_slice_async = 1; | |
3917 | if (!cfq_slice_idle) | |
3918 | cfq_slice_idle = 1; | |
3919 | ||
1da177e4 LT |
3920 | if (cfq_slab_setup()) |
3921 | return -ENOMEM; | |
3922 | ||
2fdd82bd | 3923 | elv_register(&iosched_cfq); |
3e252066 | 3924 | blkio_policy_register(&blkio_policy_cfq); |
1da177e4 | 3925 | |
2fdd82bd | 3926 | return 0; |
1da177e4 LT |
3927 | } |
3928 | ||
3929 | static void __exit cfq_exit(void) | |
3930 | { | |
6e9a4738 | 3931 | DECLARE_COMPLETION_ONSTACK(all_gone); |
3e252066 | 3932 | blkio_policy_unregister(&blkio_policy_cfq); |
1da177e4 | 3933 | elv_unregister(&iosched_cfq); |
334e94de | 3934 | ioc_gone = &all_gone; |
fba82272 OH |
3935 | /* ioc_gone's update must be visible before reading ioc_count */ |
3936 | smp_wmb(); | |
d6de8be7 JA |
3937 | |
3938 | /* | |
3939 | * this also protects us from entering cfq_slab_kill() with | |
3940 | * pending RCU callbacks | |
3941 | */ | |
245b2e70 | 3942 | if (elv_ioc_count_read(cfq_ioc_count)) |
9a11b4ed | 3943 | wait_for_completion(&all_gone); |
83521d3e | 3944 | cfq_slab_kill(); |
1da177e4 LT |
3945 | } |
3946 | ||
3947 | module_init(cfq_init); | |
3948 | module_exit(cfq_exit); | |
3949 | ||
3950 | MODULE_AUTHOR("Jens Axboe"); | |
3951 | MODULE_LICENSE("GPL"); | |
3952 | MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler"); |