Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
1da177e4 LT |
2 | * CFQ, or complete fairness queueing, disk scheduler. |
3 | * | |
4 | * Based on ideas from a previously unfinished io | |
5 | * scheduler (round robin per-process disk scheduling) and Andrea Arcangeli. | |
6 | * | |
0fe23479 | 7 | * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk> |
1da177e4 | 8 | */ |
1da177e4 | 9 | #include <linux/module.h> |
5a0e3ad6 | 10 | #include <linux/slab.h> |
1cc9be68 AV |
11 | #include <linux/blkdev.h> |
12 | #include <linux/elevator.h> | |
ad5ebd2f | 13 | #include <linux/jiffies.h> |
1da177e4 | 14 | #include <linux/rbtree.h> |
22e2c507 | 15 | #include <linux/ioprio.h> |
7b679138 | 16 | #include <linux/blktrace_api.h> |
e98ef89b | 17 | #include "cfq.h" |
1da177e4 LT |
18 | |
19 | /* | |
20 | * tunables | |
21 | */ | |
fe094d98 | 22 | /* max queue in one round of service */ |
abc3c744 | 23 | static const int cfq_quantum = 8; |
64100099 | 24 | static const int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 }; |
fe094d98 JA |
25 | /* maximum backwards seek, in KiB */ |
26 | static const int cfq_back_max = 16 * 1024; | |
27 | /* penalty of a backwards seek */ | |
28 | static const int cfq_back_penalty = 2; | |
64100099 | 29 | static const int cfq_slice_sync = HZ / 10; |
3b18152c | 30 | static int cfq_slice_async = HZ / 25; |
64100099 | 31 | static const int cfq_slice_async_rq = 2; |
caaa5f9f | 32 | static int cfq_slice_idle = HZ / 125; |
5db5d642 CZ |
33 | static const int cfq_target_latency = HZ * 3/10; /* 300 ms */ |
34 | static const int cfq_hist_divisor = 4; | |
22e2c507 | 35 | |
d9e7620e | 36 | /* |
0871714e | 37 | * offset from end of service tree |
d9e7620e | 38 | */ |
0871714e | 39 | #define CFQ_IDLE_DELAY (HZ / 5) |
d9e7620e JA |
40 | |
41 | /* | |
42 | * below this threshold, we consider thinktime immediate | |
43 | */ | |
44 | #define CFQ_MIN_TT (2) | |
45 | ||
22e2c507 | 46 | #define CFQ_SLICE_SCALE (5) |
45333d5a | 47 | #define CFQ_HW_QUEUE_MIN (5) |
25bc6b07 | 48 | #define CFQ_SERVICE_SHIFT 12 |
22e2c507 | 49 | |
3dde36dd | 50 | #define CFQQ_SEEK_THR (sector_t)(8 * 100) |
e9ce335d | 51 | #define CFQQ_CLOSE_THR (sector_t)(8 * 1024) |
41647e7a | 52 | #define CFQQ_SECT_THR_NONROT (sector_t)(2 * 32) |
3dde36dd | 53 | #define CFQQ_SEEKY(cfqq) (hweight32(cfqq->seek_history) > 32/8) |
ae54abed | 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) |
7f1dc8a2 | 58 | #define RQ_CFQG(rq) (struct cfq_group *) ((rq)->elevator_private3) |
1da177e4 | 59 | |
e18b890b CL |
60 | static struct kmem_cache *cfq_pool; |
61 | static struct kmem_cache *cfq_ioc_pool; | |
1da177e4 | 62 | |
245b2e70 | 63 | static DEFINE_PER_CPU(unsigned long, cfq_ioc_count); |
334e94de | 64 | static struct completion *ioc_gone; |
9a11b4ed | 65 | static DEFINE_SPINLOCK(ioc_gone_lock); |
334e94de | 66 | |
80b15c73 KK |
67 | static DEFINE_SPINLOCK(cic_index_lock); |
68 | static DEFINE_IDA(cic_index_ida); | |
69 | ||
22e2c507 JA |
70 | #define CFQ_PRIO_LISTS IOPRIO_BE_NR |
71 | #define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE) | |
22e2c507 JA |
72 | #define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT) |
73 | ||
206dc69b | 74 | #define sample_valid(samples) ((samples) > 80) |
1fa8f6d6 | 75 | #define rb_entry_cfqg(node) rb_entry((node), struct cfq_group, rb_node) |
206dc69b | 76 | |
cc09e299 JA |
77 | /* |
78 | * Most of our rbtree usage is for sorting with min extraction, so | |
79 | * if we cache the leftmost node we don't have to walk down the tree | |
80 | * to find it. Idea borrowed from Ingo Molnars CFS scheduler. We should | |
81 | * move this into the elevator for the rq sorting as well. | |
82 | */ | |
83 | struct cfq_rb_root { | |
84 | struct rb_root rb; | |
85 | struct rb_node *left; | |
aa6f6a3d | 86 | unsigned count; |
73e9ffdd | 87 | unsigned total_weight; |
1fa8f6d6 | 88 | u64 min_vdisktime; |
25bc6b07 | 89 | struct rb_node *active; |
cc09e299 | 90 | }; |
73e9ffdd RK |
91 | #define CFQ_RB_ROOT (struct cfq_rb_root) { .rb = RB_ROOT, .left = NULL, \ |
92 | .count = 0, .min_vdisktime = 0, } | |
cc09e299 | 93 | |
6118b70b JA |
94 | /* |
95 | * Per process-grouping structure | |
96 | */ | |
97 | struct cfq_queue { | |
98 | /* reference count */ | |
99 | atomic_t ref; | |
100 | /* various state flags, see below */ | |
101 | unsigned int flags; | |
102 | /* parent cfq_data */ | |
103 | struct cfq_data *cfqd; | |
104 | /* service_tree member */ | |
105 | struct rb_node rb_node; | |
106 | /* service_tree key */ | |
107 | unsigned long rb_key; | |
108 | /* prio tree member */ | |
109 | struct rb_node p_node; | |
110 | /* prio tree root we belong to, if any */ | |
111 | struct rb_root *p_root; | |
112 | /* sorted list of pending requests */ | |
113 | struct rb_root sort_list; | |
114 | /* if fifo isn't expired, next request to serve */ | |
115 | struct request *next_rq; | |
116 | /* requests queued in sort_list */ | |
117 | int queued[2]; | |
118 | /* currently allocated requests */ | |
119 | int allocated[2]; | |
120 | /* fifo list of requests in sort_list */ | |
121 | struct list_head fifo; | |
122 | ||
dae739eb VG |
123 | /* time when queue got scheduled in to dispatch first request. */ |
124 | unsigned long dispatch_start; | |
f75edf2d | 125 | unsigned int allocated_slice; |
c4081ba5 | 126 | unsigned int slice_dispatch; |
dae739eb VG |
127 | /* time when first request from queue completed and slice started. */ |
128 | unsigned long slice_start; | |
6118b70b JA |
129 | unsigned long slice_end; |
130 | long slice_resid; | |
6118b70b JA |
131 | |
132 | /* pending metadata requests */ | |
133 | int meta_pending; | |
134 | /* number of requests that are on the dispatch list or inside driver */ | |
135 | int dispatched; | |
136 | ||
137 | /* io prio of this group */ | |
138 | unsigned short ioprio, org_ioprio; | |
139 | unsigned short ioprio_class, org_ioprio_class; | |
140 | ||
c4081ba5 RK |
141 | pid_t pid; |
142 | ||
3dde36dd | 143 | u32 seek_history; |
b2c18e1e JM |
144 | sector_t last_request_pos; |
145 | ||
aa6f6a3d | 146 | struct cfq_rb_root *service_tree; |
df5fe3e8 | 147 | struct cfq_queue *new_cfqq; |
cdb16e8f | 148 | struct cfq_group *cfqg; |
ae30c286 | 149 | struct cfq_group *orig_cfqg; |
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 | ||
53c583d2 CZ |
230 | int rq_in_driver; |
231 | int rq_in_flight[2]; | |
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 | 276 | |
80b15c73 | 277 | unsigned int cic_index; |
d9ff4187 | 278 | struct list_head cic_list; |
1da177e4 | 279 | |
6118b70b JA |
280 | /* |
281 | * Fallback dummy cfqq for extreme OOM conditions | |
282 | */ | |
283 | struct cfq_queue oom_cfqq; | |
365722bb | 284 | |
573412b2 | 285 | unsigned long last_delayed_sync; |
25fb5169 VG |
286 | |
287 | /* List of cfq groups being managed on this device*/ | |
288 | struct hlist_head cfqg_list; | |
bb729bc9 | 289 | struct rcu_head rcu; |
1da177e4 LT |
290 | }; |
291 | ||
25fb5169 VG |
292 | static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd); |
293 | ||
cdb16e8f VG |
294 | static struct cfq_rb_root *service_tree_for(struct cfq_group *cfqg, |
295 | enum wl_prio_t prio, | |
65b32a57 | 296 | enum wl_type_t type) |
c0324a02 | 297 | { |
1fa8f6d6 VG |
298 | if (!cfqg) |
299 | return NULL; | |
300 | ||
c0324a02 | 301 | if (prio == IDLE_WORKLOAD) |
cdb16e8f | 302 | return &cfqg->service_tree_idle; |
c0324a02 | 303 | |
cdb16e8f | 304 | return &cfqg->service_trees[prio][type]; |
c0324a02 CZ |
305 | } |
306 | ||
3b18152c | 307 | enum cfqq_state_flags { |
b0b8d749 JA |
308 | CFQ_CFQQ_FLAG_on_rr = 0, /* on round-robin busy list */ |
309 | CFQ_CFQQ_FLAG_wait_request, /* waiting for a request */ | |
b029195d | 310 | CFQ_CFQQ_FLAG_must_dispatch, /* must be allowed a dispatch */ |
b0b8d749 | 311 | CFQ_CFQQ_FLAG_must_alloc_slice, /* per-slice must_alloc flag */ |
b0b8d749 JA |
312 | CFQ_CFQQ_FLAG_fifo_expire, /* FIFO checked in this slice */ |
313 | CFQ_CFQQ_FLAG_idle_window, /* slice idling enabled */ | |
314 | CFQ_CFQQ_FLAG_prio_changed, /* task priority has changed */ | |
44f7c160 | 315 | CFQ_CFQQ_FLAG_slice_new, /* no requests dispatched in slice */ |
91fac317 | 316 | CFQ_CFQQ_FLAG_sync, /* synchronous queue */ |
b3b6d040 | 317 | CFQ_CFQQ_FLAG_coop, /* cfqq is shared */ |
ae54abed | 318 | CFQ_CFQQ_FLAG_split_coop, /* shared cfqq will be splitted */ |
76280aff | 319 | CFQ_CFQQ_FLAG_deep, /* sync cfqq experienced large depth */ |
f75edf2d | 320 | CFQ_CFQQ_FLAG_wait_busy, /* Waiting for next request */ |
3b18152c JA |
321 | }; |
322 | ||
323 | #define CFQ_CFQQ_FNS(name) \ | |
324 | static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \ | |
325 | { \ | |
fe094d98 | 326 | (cfqq)->flags |= (1 << CFQ_CFQQ_FLAG_##name); \ |
3b18152c JA |
327 | } \ |
328 | static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \ | |
329 | { \ | |
fe094d98 | 330 | (cfqq)->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \ |
3b18152c JA |
331 | } \ |
332 | static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \ | |
333 | { \ | |
fe094d98 | 334 | return ((cfqq)->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \ |
3b18152c JA |
335 | } |
336 | ||
337 | CFQ_CFQQ_FNS(on_rr); | |
338 | CFQ_CFQQ_FNS(wait_request); | |
b029195d | 339 | CFQ_CFQQ_FNS(must_dispatch); |
3b18152c | 340 | CFQ_CFQQ_FNS(must_alloc_slice); |
3b18152c JA |
341 | CFQ_CFQQ_FNS(fifo_expire); |
342 | CFQ_CFQQ_FNS(idle_window); | |
343 | CFQ_CFQQ_FNS(prio_changed); | |
44f7c160 | 344 | CFQ_CFQQ_FNS(slice_new); |
91fac317 | 345 | CFQ_CFQQ_FNS(sync); |
a36e71f9 | 346 | CFQ_CFQQ_FNS(coop); |
ae54abed | 347 | CFQ_CFQQ_FNS(split_coop); |
76280aff | 348 | CFQ_CFQQ_FNS(deep); |
f75edf2d | 349 | CFQ_CFQQ_FNS(wait_busy); |
3b18152c JA |
350 | #undef CFQ_CFQQ_FNS |
351 | ||
afc24d49 | 352 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
2868ef7b VG |
353 | #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \ |
354 | blk_add_trace_msg((cfqd)->queue, "cfq%d%c %s " fmt, (cfqq)->pid, \ | |
355 | cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \ | |
356 | blkg_path(&(cfqq)->cfqg->blkg), ##args); | |
357 | ||
358 | #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) \ | |
359 | blk_add_trace_msg((cfqd)->queue, "%s " fmt, \ | |
360 | blkg_path(&(cfqg)->blkg), ##args); \ | |
361 | ||
362 | #else | |
7b679138 JA |
363 | #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \ |
364 | blk_add_trace_msg((cfqd)->queue, "cfq%d " fmt, (cfqq)->pid, ##args) | |
2868ef7b VG |
365 | #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) do {} while (0); |
366 | #endif | |
7b679138 JA |
367 | #define cfq_log(cfqd, fmt, args...) \ |
368 | blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args) | |
369 | ||
615f0259 VG |
370 | /* Traverses through cfq group service trees */ |
371 | #define for_each_cfqg_st(cfqg, i, j, st) \ | |
372 | for (i = 0; i <= IDLE_WORKLOAD; i++) \ | |
373 | for (j = 0, st = i < IDLE_WORKLOAD ? &cfqg->service_trees[i][j]\ | |
374 | : &cfqg->service_tree_idle; \ | |
375 | (i < IDLE_WORKLOAD && j <= SYNC_WORKLOAD) || \ | |
376 | (i == IDLE_WORKLOAD && j == 0); \ | |
377 | j++, st = i < IDLE_WORKLOAD ? \ | |
378 | &cfqg->service_trees[i][j]: NULL) \ | |
379 | ||
380 | ||
c0324a02 CZ |
381 | static inline enum wl_prio_t cfqq_prio(struct cfq_queue *cfqq) |
382 | { | |
383 | if (cfq_class_idle(cfqq)) | |
384 | return IDLE_WORKLOAD; | |
385 | if (cfq_class_rt(cfqq)) | |
386 | return RT_WORKLOAD; | |
387 | return BE_WORKLOAD; | |
388 | } | |
389 | ||
718eee05 CZ |
390 | |
391 | static enum wl_type_t cfqq_type(struct cfq_queue *cfqq) | |
392 | { | |
393 | if (!cfq_cfqq_sync(cfqq)) | |
394 | return ASYNC_WORKLOAD; | |
395 | if (!cfq_cfqq_idle_window(cfqq)) | |
396 | return SYNC_NOIDLE_WORKLOAD; | |
397 | return SYNC_WORKLOAD; | |
398 | } | |
399 | ||
58ff82f3 VG |
400 | static inline int cfq_group_busy_queues_wl(enum wl_prio_t wl, |
401 | struct cfq_data *cfqd, | |
402 | struct cfq_group *cfqg) | |
c0324a02 CZ |
403 | { |
404 | if (wl == IDLE_WORKLOAD) | |
cdb16e8f | 405 | return cfqg->service_tree_idle.count; |
c0324a02 | 406 | |
cdb16e8f VG |
407 | return cfqg->service_trees[wl][ASYNC_WORKLOAD].count |
408 | + cfqg->service_trees[wl][SYNC_NOIDLE_WORKLOAD].count | |
409 | + cfqg->service_trees[wl][SYNC_WORKLOAD].count; | |
c0324a02 CZ |
410 | } |
411 | ||
f26bd1f0 VG |
412 | static inline int cfqg_busy_async_queues(struct cfq_data *cfqd, |
413 | struct cfq_group *cfqg) | |
414 | { | |
415 | return cfqg->service_trees[RT_WORKLOAD][ASYNC_WORKLOAD].count | |
416 | + cfqg->service_trees[BE_WORKLOAD][ASYNC_WORKLOAD].count; | |
417 | } | |
418 | ||
165125e1 | 419 | static void cfq_dispatch_insert(struct request_queue *, struct request *); |
a6151c3a | 420 | static struct cfq_queue *cfq_get_queue(struct cfq_data *, bool, |
fd0928df | 421 | struct io_context *, gfp_t); |
4ac845a2 | 422 | static struct cfq_io_context *cfq_cic_lookup(struct cfq_data *, |
91fac317 VT |
423 | struct io_context *); |
424 | ||
425 | static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_context *cic, | |
a6151c3a | 426 | bool is_sync) |
91fac317 | 427 | { |
a6151c3a | 428 | return cic->cfqq[is_sync]; |
91fac317 VT |
429 | } |
430 | ||
431 | static inline void cic_set_cfqq(struct cfq_io_context *cic, | |
a6151c3a | 432 | struct cfq_queue *cfqq, bool is_sync) |
91fac317 | 433 | { |
a6151c3a | 434 | cic->cfqq[is_sync] = cfqq; |
91fac317 VT |
435 | } |
436 | ||
bca4b914 | 437 | #define CIC_DEAD_KEY 1ul |
80b15c73 | 438 | #define CIC_DEAD_INDEX_SHIFT 1 |
bca4b914 KK |
439 | |
440 | static inline void *cfqd_dead_key(struct cfq_data *cfqd) | |
441 | { | |
80b15c73 | 442 | return (void *)(cfqd->cic_index << CIC_DEAD_INDEX_SHIFT | CIC_DEAD_KEY); |
bca4b914 KK |
443 | } |
444 | ||
445 | static inline struct cfq_data *cic_to_cfqd(struct cfq_io_context *cic) | |
446 | { | |
447 | struct cfq_data *cfqd = cic->key; | |
448 | ||
449 | if (unlikely((unsigned long) cfqd & CIC_DEAD_KEY)) | |
450 | return NULL; | |
451 | ||
452 | return cfqd; | |
453 | } | |
454 | ||
91fac317 VT |
455 | /* |
456 | * We regard a request as SYNC, if it's either a read or has the SYNC bit | |
457 | * set (in which case it could also be direct WRITE). | |
458 | */ | |
a6151c3a | 459 | static inline bool cfq_bio_sync(struct bio *bio) |
91fac317 | 460 | { |
7b6d91da | 461 | return bio_data_dir(bio) == READ || (bio->bi_rw & REQ_SYNC); |
91fac317 | 462 | } |
1da177e4 | 463 | |
99f95e52 AM |
464 | /* |
465 | * scheduler run of queue, if there are requests pending and no one in the | |
466 | * driver that will restart queueing | |
467 | */ | |
23e018a1 | 468 | static inline void cfq_schedule_dispatch(struct cfq_data *cfqd) |
99f95e52 | 469 | { |
7b679138 JA |
470 | if (cfqd->busy_queues) { |
471 | cfq_log(cfqd, "schedule dispatch"); | |
23e018a1 | 472 | kblockd_schedule_work(cfqd->queue, &cfqd->unplug_work); |
7b679138 | 473 | } |
99f95e52 AM |
474 | } |
475 | ||
165125e1 | 476 | static int cfq_queue_empty(struct request_queue *q) |
99f95e52 AM |
477 | { |
478 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
479 | ||
f04a6424 | 480 | return !cfqd->rq_queued; |
99f95e52 AM |
481 | } |
482 | ||
44f7c160 JA |
483 | /* |
484 | * Scale schedule slice based on io priority. Use the sync time slice only | |
485 | * if a queue is marked sync and has sync io queued. A sync queue with async | |
486 | * io only, should not get full sync slice length. | |
487 | */ | |
a6151c3a | 488 | static inline int cfq_prio_slice(struct cfq_data *cfqd, bool sync, |
d9e7620e | 489 | unsigned short prio) |
44f7c160 | 490 | { |
d9e7620e | 491 | const int base_slice = cfqd->cfq_slice[sync]; |
44f7c160 | 492 | |
d9e7620e JA |
493 | WARN_ON(prio >= IOPRIO_BE_NR); |
494 | ||
495 | return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - prio)); | |
496 | } | |
44f7c160 | 497 | |
d9e7620e JA |
498 | static inline int |
499 | cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
500 | { | |
501 | return cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio); | |
44f7c160 JA |
502 | } |
503 | ||
25bc6b07 VG |
504 | static inline u64 cfq_scale_slice(unsigned long delta, struct cfq_group *cfqg) |
505 | { | |
506 | u64 d = delta << CFQ_SERVICE_SHIFT; | |
507 | ||
508 | d = d * BLKIO_WEIGHT_DEFAULT; | |
509 | do_div(d, cfqg->weight); | |
510 | return d; | |
511 | } | |
512 | ||
513 | static inline u64 max_vdisktime(u64 min_vdisktime, u64 vdisktime) | |
514 | { | |
515 | s64 delta = (s64)(vdisktime - min_vdisktime); | |
516 | if (delta > 0) | |
517 | min_vdisktime = vdisktime; | |
518 | ||
519 | return min_vdisktime; | |
520 | } | |
521 | ||
522 | static inline u64 min_vdisktime(u64 min_vdisktime, u64 vdisktime) | |
523 | { | |
524 | s64 delta = (s64)(vdisktime - min_vdisktime); | |
525 | if (delta < 0) | |
526 | min_vdisktime = vdisktime; | |
527 | ||
528 | return min_vdisktime; | |
529 | } | |
530 | ||
531 | static void update_min_vdisktime(struct cfq_rb_root *st) | |
532 | { | |
533 | u64 vdisktime = st->min_vdisktime; | |
534 | struct cfq_group *cfqg; | |
535 | ||
536 | if (st->active) { | |
537 | cfqg = rb_entry_cfqg(st->active); | |
538 | vdisktime = cfqg->vdisktime; | |
539 | } | |
540 | ||
541 | if (st->left) { | |
542 | cfqg = rb_entry_cfqg(st->left); | |
543 | vdisktime = min_vdisktime(vdisktime, cfqg->vdisktime); | |
544 | } | |
545 | ||
546 | st->min_vdisktime = max_vdisktime(st->min_vdisktime, vdisktime); | |
547 | } | |
548 | ||
5db5d642 CZ |
549 | /* |
550 | * get averaged number of queues of RT/BE priority. | |
551 | * average is updated, with a formula that gives more weight to higher numbers, | |
552 | * to quickly follows sudden increases and decrease slowly | |
553 | */ | |
554 | ||
58ff82f3 VG |
555 | static inline unsigned cfq_group_get_avg_queues(struct cfq_data *cfqd, |
556 | struct cfq_group *cfqg, bool rt) | |
5869619c | 557 | { |
5db5d642 CZ |
558 | unsigned min_q, max_q; |
559 | unsigned mult = cfq_hist_divisor - 1; | |
560 | unsigned round = cfq_hist_divisor / 2; | |
58ff82f3 | 561 | unsigned busy = cfq_group_busy_queues_wl(rt, cfqd, cfqg); |
5db5d642 | 562 | |
58ff82f3 VG |
563 | min_q = min(cfqg->busy_queues_avg[rt], busy); |
564 | max_q = max(cfqg->busy_queues_avg[rt], busy); | |
565 | cfqg->busy_queues_avg[rt] = (mult * max_q + min_q + round) / | |
5db5d642 | 566 | cfq_hist_divisor; |
58ff82f3 VG |
567 | return cfqg->busy_queues_avg[rt]; |
568 | } | |
569 | ||
570 | static inline unsigned | |
571 | cfq_group_slice(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
572 | { | |
573 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
574 | ||
575 | return cfq_target_latency * cfqg->weight / st->total_weight; | |
5db5d642 CZ |
576 | } |
577 | ||
44f7c160 JA |
578 | static inline void |
579 | cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
580 | { | |
5db5d642 CZ |
581 | unsigned slice = cfq_prio_to_slice(cfqd, cfqq); |
582 | if (cfqd->cfq_latency) { | |
58ff82f3 VG |
583 | /* |
584 | * interested queues (we consider only the ones with the same | |
585 | * priority class in the cfq group) | |
586 | */ | |
587 | unsigned iq = cfq_group_get_avg_queues(cfqd, cfqq->cfqg, | |
588 | cfq_class_rt(cfqq)); | |
5db5d642 CZ |
589 | unsigned sync_slice = cfqd->cfq_slice[1]; |
590 | unsigned expect_latency = sync_slice * iq; | |
58ff82f3 VG |
591 | unsigned group_slice = cfq_group_slice(cfqd, cfqq->cfqg); |
592 | ||
593 | if (expect_latency > group_slice) { | |
5db5d642 CZ |
594 | unsigned base_low_slice = 2 * cfqd->cfq_slice_idle; |
595 | /* scale low_slice according to IO priority | |
596 | * and sync vs async */ | |
597 | unsigned low_slice = | |
598 | min(slice, base_low_slice * slice / sync_slice); | |
599 | /* the adapted slice value is scaled to fit all iqs | |
600 | * into the target latency */ | |
58ff82f3 | 601 | slice = max(slice * group_slice / expect_latency, |
5db5d642 CZ |
602 | low_slice); |
603 | } | |
604 | } | |
dae739eb | 605 | cfqq->slice_start = jiffies; |
5db5d642 | 606 | cfqq->slice_end = jiffies + slice; |
f75edf2d | 607 | cfqq->allocated_slice = slice; |
7b679138 | 608 | cfq_log_cfqq(cfqd, cfqq, "set_slice=%lu", cfqq->slice_end - jiffies); |
44f7c160 JA |
609 | } |
610 | ||
611 | /* | |
612 | * We need to wrap this check in cfq_cfqq_slice_new(), since ->slice_end | |
613 | * isn't valid until the first request from the dispatch is activated | |
614 | * and the slice time set. | |
615 | */ | |
a6151c3a | 616 | static inline bool cfq_slice_used(struct cfq_queue *cfqq) |
44f7c160 JA |
617 | { |
618 | if (cfq_cfqq_slice_new(cfqq)) | |
619 | return 0; | |
620 | if (time_before(jiffies, cfqq->slice_end)) | |
621 | return 0; | |
622 | ||
623 | return 1; | |
624 | } | |
625 | ||
1da177e4 | 626 | /* |
5e705374 | 627 | * Lifted from AS - choose which of rq1 and rq2 that is best served now. |
1da177e4 | 628 | * We choose the request that is closest to the head right now. Distance |
e8a99053 | 629 | * behind the head is penalized and only allowed to a certain extent. |
1da177e4 | 630 | */ |
5e705374 | 631 | static struct request * |
cf7c25cf | 632 | cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2, sector_t last) |
1da177e4 | 633 | { |
cf7c25cf | 634 | sector_t s1, s2, d1 = 0, d2 = 0; |
1da177e4 | 635 | unsigned long back_max; |
e8a99053 AM |
636 | #define CFQ_RQ1_WRAP 0x01 /* request 1 wraps */ |
637 | #define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */ | |
638 | unsigned wrap = 0; /* bit mask: requests behind the disk head? */ | |
1da177e4 | 639 | |
5e705374 JA |
640 | if (rq1 == NULL || rq1 == rq2) |
641 | return rq2; | |
642 | if (rq2 == NULL) | |
643 | return rq1; | |
9c2c38a1 | 644 | |
5e705374 JA |
645 | if (rq_is_sync(rq1) && !rq_is_sync(rq2)) |
646 | return rq1; | |
647 | else if (rq_is_sync(rq2) && !rq_is_sync(rq1)) | |
648 | return rq2; | |
7b6d91da | 649 | if ((rq1->cmd_flags & REQ_META) && !(rq2->cmd_flags & REQ_META)) |
374f84ac | 650 | return rq1; |
7b6d91da CH |
651 | else if ((rq2->cmd_flags & REQ_META) && |
652 | !(rq1->cmd_flags & REQ_META)) | |
374f84ac | 653 | return rq2; |
1da177e4 | 654 | |
83096ebf TH |
655 | s1 = blk_rq_pos(rq1); |
656 | s2 = blk_rq_pos(rq2); | |
1da177e4 | 657 | |
1da177e4 LT |
658 | /* |
659 | * by definition, 1KiB is 2 sectors | |
660 | */ | |
661 | back_max = cfqd->cfq_back_max * 2; | |
662 | ||
663 | /* | |
664 | * Strict one way elevator _except_ in the case where we allow | |
665 | * short backward seeks which are biased as twice the cost of a | |
666 | * similar forward seek. | |
667 | */ | |
668 | if (s1 >= last) | |
669 | d1 = s1 - last; | |
670 | else if (s1 + back_max >= last) | |
671 | d1 = (last - s1) * cfqd->cfq_back_penalty; | |
672 | else | |
e8a99053 | 673 | wrap |= CFQ_RQ1_WRAP; |
1da177e4 LT |
674 | |
675 | if (s2 >= last) | |
676 | d2 = s2 - last; | |
677 | else if (s2 + back_max >= last) | |
678 | d2 = (last - s2) * cfqd->cfq_back_penalty; | |
679 | else | |
e8a99053 | 680 | wrap |= CFQ_RQ2_WRAP; |
1da177e4 LT |
681 | |
682 | /* Found required data */ | |
e8a99053 AM |
683 | |
684 | /* | |
685 | * By doing switch() on the bit mask "wrap" we avoid having to | |
686 | * check two variables for all permutations: --> faster! | |
687 | */ | |
688 | switch (wrap) { | |
5e705374 | 689 | case 0: /* common case for CFQ: rq1 and rq2 not wrapped */ |
e8a99053 | 690 | if (d1 < d2) |
5e705374 | 691 | return rq1; |
e8a99053 | 692 | else if (d2 < d1) |
5e705374 | 693 | return rq2; |
e8a99053 AM |
694 | else { |
695 | if (s1 >= s2) | |
5e705374 | 696 | return rq1; |
e8a99053 | 697 | else |
5e705374 | 698 | return rq2; |
e8a99053 | 699 | } |
1da177e4 | 700 | |
e8a99053 | 701 | case CFQ_RQ2_WRAP: |
5e705374 | 702 | return rq1; |
e8a99053 | 703 | case CFQ_RQ1_WRAP: |
5e705374 JA |
704 | return rq2; |
705 | case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both rqs wrapped */ | |
e8a99053 AM |
706 | default: |
707 | /* | |
708 | * Since both rqs are wrapped, | |
709 | * start with the one that's further behind head | |
710 | * (--> only *one* back seek required), | |
711 | * since back seek takes more time than forward. | |
712 | */ | |
713 | if (s1 <= s2) | |
5e705374 | 714 | return rq1; |
1da177e4 | 715 | else |
5e705374 | 716 | return rq2; |
1da177e4 LT |
717 | } |
718 | } | |
719 | ||
498d3aa2 JA |
720 | /* |
721 | * The below is leftmost cache rbtree addon | |
722 | */ | |
0871714e | 723 | static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root) |
cc09e299 | 724 | { |
615f0259 VG |
725 | /* Service tree is empty */ |
726 | if (!root->count) | |
727 | return NULL; | |
728 | ||
cc09e299 JA |
729 | if (!root->left) |
730 | root->left = rb_first(&root->rb); | |
731 | ||
0871714e JA |
732 | if (root->left) |
733 | return rb_entry(root->left, struct cfq_queue, rb_node); | |
734 | ||
735 | return NULL; | |
cc09e299 JA |
736 | } |
737 | ||
1fa8f6d6 VG |
738 | static struct cfq_group *cfq_rb_first_group(struct cfq_rb_root *root) |
739 | { | |
740 | if (!root->left) | |
741 | root->left = rb_first(&root->rb); | |
742 | ||
743 | if (root->left) | |
744 | return rb_entry_cfqg(root->left); | |
745 | ||
746 | return NULL; | |
747 | } | |
748 | ||
a36e71f9 JA |
749 | static void rb_erase_init(struct rb_node *n, struct rb_root *root) |
750 | { | |
751 | rb_erase(n, root); | |
752 | RB_CLEAR_NODE(n); | |
753 | } | |
754 | ||
cc09e299 JA |
755 | static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root) |
756 | { | |
757 | if (root->left == n) | |
758 | root->left = NULL; | |
a36e71f9 | 759 | rb_erase_init(n, &root->rb); |
aa6f6a3d | 760 | --root->count; |
cc09e299 JA |
761 | } |
762 | ||
1da177e4 LT |
763 | /* |
764 | * would be nice to take fifo expire time into account as well | |
765 | */ | |
5e705374 JA |
766 | static struct request * |
767 | cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
768 | struct request *last) | |
1da177e4 | 769 | { |
21183b07 JA |
770 | struct rb_node *rbnext = rb_next(&last->rb_node); |
771 | struct rb_node *rbprev = rb_prev(&last->rb_node); | |
5e705374 | 772 | struct request *next = NULL, *prev = NULL; |
1da177e4 | 773 | |
21183b07 | 774 | BUG_ON(RB_EMPTY_NODE(&last->rb_node)); |
1da177e4 LT |
775 | |
776 | if (rbprev) | |
5e705374 | 777 | prev = rb_entry_rq(rbprev); |
1da177e4 | 778 | |
21183b07 | 779 | if (rbnext) |
5e705374 | 780 | next = rb_entry_rq(rbnext); |
21183b07 JA |
781 | else { |
782 | rbnext = rb_first(&cfqq->sort_list); | |
783 | if (rbnext && rbnext != &last->rb_node) | |
5e705374 | 784 | next = rb_entry_rq(rbnext); |
21183b07 | 785 | } |
1da177e4 | 786 | |
cf7c25cf | 787 | return cfq_choose_req(cfqd, next, prev, blk_rq_pos(last)); |
1da177e4 LT |
788 | } |
789 | ||
d9e7620e JA |
790 | static unsigned long cfq_slice_offset(struct cfq_data *cfqd, |
791 | struct cfq_queue *cfqq) | |
1da177e4 | 792 | { |
d9e7620e JA |
793 | /* |
794 | * just an approximation, should be ok. | |
795 | */ | |
cdb16e8f | 796 | return (cfqq->cfqg->nr_cfqq - 1) * (cfq_prio_slice(cfqd, 1, 0) - |
464191c6 | 797 | cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio)); |
d9e7620e JA |
798 | } |
799 | ||
1fa8f6d6 VG |
800 | static inline s64 |
801 | cfqg_key(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
802 | { | |
803 | return cfqg->vdisktime - st->min_vdisktime; | |
804 | } | |
805 | ||
806 | static void | |
807 | __cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
808 | { | |
809 | struct rb_node **node = &st->rb.rb_node; | |
810 | struct rb_node *parent = NULL; | |
811 | struct cfq_group *__cfqg; | |
812 | s64 key = cfqg_key(st, cfqg); | |
813 | int left = 1; | |
814 | ||
815 | while (*node != NULL) { | |
816 | parent = *node; | |
817 | __cfqg = rb_entry_cfqg(parent); | |
818 | ||
819 | if (key < cfqg_key(st, __cfqg)) | |
820 | node = &parent->rb_left; | |
821 | else { | |
822 | node = &parent->rb_right; | |
823 | left = 0; | |
824 | } | |
825 | } | |
826 | ||
827 | if (left) | |
828 | st->left = &cfqg->rb_node; | |
829 | ||
830 | rb_link_node(&cfqg->rb_node, parent, node); | |
831 | rb_insert_color(&cfqg->rb_node, &st->rb); | |
832 | } | |
833 | ||
834 | static void | |
835 | cfq_group_service_tree_add(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
836 | { | |
837 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
838 | struct cfq_group *__cfqg; | |
839 | struct rb_node *n; | |
840 | ||
841 | cfqg->nr_cfqq++; | |
842 | if (cfqg->on_st) | |
843 | return; | |
844 | ||
845 | /* | |
846 | * Currently put the group at the end. Later implement something | |
847 | * so that groups get lesser vtime based on their weights, so that | |
848 | * if group does not loose all if it was not continously backlogged. | |
849 | */ | |
850 | n = rb_last(&st->rb); | |
851 | if (n) { | |
852 | __cfqg = rb_entry_cfqg(n); | |
853 | cfqg->vdisktime = __cfqg->vdisktime + CFQ_IDLE_DELAY; | |
854 | } else | |
855 | cfqg->vdisktime = st->min_vdisktime; | |
856 | ||
857 | __cfq_group_service_tree_add(st, cfqg); | |
858 | cfqg->on_st = true; | |
58ff82f3 | 859 | st->total_weight += cfqg->weight; |
1fa8f6d6 VG |
860 | } |
861 | ||
862 | static void | |
863 | cfq_group_service_tree_del(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
864 | { | |
865 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
866 | ||
25bc6b07 VG |
867 | if (st->active == &cfqg->rb_node) |
868 | st->active = NULL; | |
869 | ||
1fa8f6d6 VG |
870 | BUG_ON(cfqg->nr_cfqq < 1); |
871 | cfqg->nr_cfqq--; | |
25bc6b07 | 872 | |
1fa8f6d6 VG |
873 | /* If there are other cfq queues under this group, don't delete it */ |
874 | if (cfqg->nr_cfqq) | |
875 | return; | |
876 | ||
2868ef7b | 877 | cfq_log_cfqg(cfqd, cfqg, "del_from_rr group"); |
1fa8f6d6 | 878 | cfqg->on_st = false; |
58ff82f3 | 879 | st->total_weight -= cfqg->weight; |
1fa8f6d6 VG |
880 | if (!RB_EMPTY_NODE(&cfqg->rb_node)) |
881 | cfq_rb_erase(&cfqg->rb_node, st); | |
dae739eb | 882 | cfqg->saved_workload_slice = 0; |
e98ef89b | 883 | cfq_blkiocg_update_dequeue_stats(&cfqg->blkg, 1); |
dae739eb VG |
884 | } |
885 | ||
886 | static inline unsigned int cfq_cfqq_slice_usage(struct cfq_queue *cfqq) | |
887 | { | |
f75edf2d | 888 | unsigned int slice_used; |
dae739eb VG |
889 | |
890 | /* | |
891 | * Queue got expired before even a single request completed or | |
892 | * got expired immediately after first request completion. | |
893 | */ | |
894 | if (!cfqq->slice_start || cfqq->slice_start == jiffies) { | |
895 | /* | |
896 | * Also charge the seek time incurred to the group, otherwise | |
897 | * if there are mutiple queues in the group, each can dispatch | |
898 | * a single request on seeky media and cause lots of seek time | |
899 | * and group will never know it. | |
900 | */ | |
901 | slice_used = max_t(unsigned, (jiffies - cfqq->dispatch_start), | |
902 | 1); | |
903 | } else { | |
904 | slice_used = jiffies - cfqq->slice_start; | |
f75edf2d VG |
905 | if (slice_used > cfqq->allocated_slice) |
906 | slice_used = cfqq->allocated_slice; | |
dae739eb VG |
907 | } |
908 | ||
9a0785b0 | 909 | cfq_log_cfqq(cfqq->cfqd, cfqq, "sl_used=%u", slice_used); |
dae739eb VG |
910 | return slice_used; |
911 | } | |
912 | ||
913 | static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg, | |
e5ff082e | 914 | struct cfq_queue *cfqq) |
dae739eb VG |
915 | { |
916 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
f26bd1f0 VG |
917 | unsigned int used_sl, charge_sl; |
918 | int nr_sync = cfqg->nr_cfqq - cfqg_busy_async_queues(cfqd, cfqg) | |
919 | - cfqg->service_tree_idle.count; | |
920 | ||
921 | BUG_ON(nr_sync < 0); | |
922 | used_sl = charge_sl = cfq_cfqq_slice_usage(cfqq); | |
dae739eb | 923 | |
f26bd1f0 VG |
924 | if (!cfq_cfqq_sync(cfqq) && !nr_sync) |
925 | charge_sl = cfqq->allocated_slice; | |
dae739eb VG |
926 | |
927 | /* Can't update vdisktime while group is on service tree */ | |
928 | cfq_rb_erase(&cfqg->rb_node, st); | |
f26bd1f0 | 929 | cfqg->vdisktime += cfq_scale_slice(charge_sl, cfqg); |
dae739eb VG |
930 | __cfq_group_service_tree_add(st, cfqg); |
931 | ||
932 | /* This group is being expired. Save the context */ | |
933 | if (time_after(cfqd->workload_expires, jiffies)) { | |
934 | cfqg->saved_workload_slice = cfqd->workload_expires | |
935 | - jiffies; | |
936 | cfqg->saved_workload = cfqd->serving_type; | |
937 | cfqg->saved_serving_prio = cfqd->serving_prio; | |
938 | } else | |
939 | cfqg->saved_workload_slice = 0; | |
2868ef7b VG |
940 | |
941 | cfq_log_cfqg(cfqd, cfqg, "served: vt=%llu min_vt=%llu", cfqg->vdisktime, | |
942 | st->min_vdisktime); | |
e98ef89b VG |
943 | cfq_blkiocg_update_timeslice_used(&cfqg->blkg, used_sl); |
944 | cfq_blkiocg_set_start_empty_time(&cfqg->blkg); | |
1fa8f6d6 VG |
945 | } |
946 | ||
25fb5169 VG |
947 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
948 | static inline struct cfq_group *cfqg_of_blkg(struct blkio_group *blkg) | |
949 | { | |
950 | if (blkg) | |
951 | return container_of(blkg, struct cfq_group, blkg); | |
952 | return NULL; | |
953 | } | |
954 | ||
f8d461d6 VG |
955 | void |
956 | cfq_update_blkio_group_weight(struct blkio_group *blkg, unsigned int weight) | |
957 | { | |
958 | cfqg_of_blkg(blkg)->weight = weight; | |
959 | } | |
960 | ||
25fb5169 VG |
961 | static struct cfq_group * |
962 | cfq_find_alloc_cfqg(struct cfq_data *cfqd, struct cgroup *cgroup, int create) | |
963 | { | |
964 | struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup); | |
965 | struct cfq_group *cfqg = NULL; | |
966 | void *key = cfqd; | |
967 | int i, j; | |
968 | struct cfq_rb_root *st; | |
22084190 VG |
969 | struct backing_dev_info *bdi = &cfqd->queue->backing_dev_info; |
970 | unsigned int major, minor; | |
25fb5169 | 971 | |
25fb5169 | 972 | cfqg = cfqg_of_blkg(blkiocg_lookup_group(blkcg, key)); |
a74b2ada RB |
973 | if (cfqg && !cfqg->blkg.dev && bdi->dev && dev_name(bdi->dev)) { |
974 | sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor); | |
975 | cfqg->blkg.dev = MKDEV(major, minor); | |
976 | goto done; | |
977 | } | |
25fb5169 VG |
978 | if (cfqg || !create) |
979 | goto done; | |
980 | ||
981 | cfqg = kzalloc_node(sizeof(*cfqg), GFP_ATOMIC, cfqd->queue->node); | |
982 | if (!cfqg) | |
983 | goto done; | |
984 | ||
25fb5169 VG |
985 | for_each_cfqg_st(cfqg, i, j, st) |
986 | *st = CFQ_RB_ROOT; | |
987 | RB_CLEAR_NODE(&cfqg->rb_node); | |
988 | ||
b1c35769 VG |
989 | /* |
990 | * Take the initial reference that will be released on destroy | |
991 | * This can be thought of a joint reference by cgroup and | |
992 | * elevator which will be dropped by either elevator exit | |
993 | * or cgroup deletion path depending on who is exiting first. | |
994 | */ | |
995 | atomic_set(&cfqg->ref, 1); | |
996 | ||
25fb5169 | 997 | /* Add group onto cgroup list */ |
22084190 | 998 | sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor); |
e98ef89b | 999 | cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg, (void *)cfqd, |
22084190 | 1000 | MKDEV(major, minor)); |
34d0f179 | 1001 | cfqg->weight = blkcg_get_weight(blkcg, cfqg->blkg.dev); |
25fb5169 VG |
1002 | |
1003 | /* Add group on cfqd list */ | |
1004 | hlist_add_head(&cfqg->cfqd_node, &cfqd->cfqg_list); | |
1005 | ||
1006 | done: | |
25fb5169 VG |
1007 | return cfqg; |
1008 | } | |
1009 | ||
1010 | /* | |
1011 | * Search for the cfq group current task belongs to. If create = 1, then also | |
1012 | * create the cfq group if it does not exist. request_queue lock must be held. | |
1013 | */ | |
1014 | static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd, int create) | |
1015 | { | |
1016 | struct cgroup *cgroup; | |
1017 | struct cfq_group *cfqg = NULL; | |
1018 | ||
1019 | rcu_read_lock(); | |
1020 | cgroup = task_cgroup(current, blkio_subsys_id); | |
1021 | cfqg = cfq_find_alloc_cfqg(cfqd, cgroup, create); | |
1022 | if (!cfqg && create) | |
1023 | cfqg = &cfqd->root_group; | |
1024 | rcu_read_unlock(); | |
1025 | return cfqg; | |
1026 | } | |
1027 | ||
7f1dc8a2 VG |
1028 | static inline struct cfq_group *cfq_ref_get_cfqg(struct cfq_group *cfqg) |
1029 | { | |
1030 | atomic_inc(&cfqg->ref); | |
1031 | return cfqg; | |
1032 | } | |
1033 | ||
25fb5169 VG |
1034 | static void cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) |
1035 | { | |
1036 | /* Currently, all async queues are mapped to root group */ | |
1037 | if (!cfq_cfqq_sync(cfqq)) | |
1038 | cfqg = &cfqq->cfqd->root_group; | |
1039 | ||
1040 | cfqq->cfqg = cfqg; | |
b1c35769 VG |
1041 | /* cfqq reference on cfqg */ |
1042 | atomic_inc(&cfqq->cfqg->ref); | |
1043 | } | |
1044 | ||
1045 | static void cfq_put_cfqg(struct cfq_group *cfqg) | |
1046 | { | |
1047 | struct cfq_rb_root *st; | |
1048 | int i, j; | |
1049 | ||
1050 | BUG_ON(atomic_read(&cfqg->ref) <= 0); | |
1051 | if (!atomic_dec_and_test(&cfqg->ref)) | |
1052 | return; | |
1053 | for_each_cfqg_st(cfqg, i, j, st) | |
1054 | BUG_ON(!RB_EMPTY_ROOT(&st->rb) || st->active != NULL); | |
1055 | kfree(cfqg); | |
1056 | } | |
1057 | ||
1058 | static void cfq_destroy_cfqg(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
1059 | { | |
1060 | /* Something wrong if we are trying to remove same group twice */ | |
1061 | BUG_ON(hlist_unhashed(&cfqg->cfqd_node)); | |
1062 | ||
1063 | hlist_del_init(&cfqg->cfqd_node); | |
1064 | ||
1065 | /* | |
1066 | * Put the reference taken at the time of creation so that when all | |
1067 | * queues are gone, group can be destroyed. | |
1068 | */ | |
1069 | cfq_put_cfqg(cfqg); | |
1070 | } | |
1071 | ||
1072 | static void cfq_release_cfq_groups(struct cfq_data *cfqd) | |
1073 | { | |
1074 | struct hlist_node *pos, *n; | |
1075 | struct cfq_group *cfqg; | |
1076 | ||
1077 | hlist_for_each_entry_safe(cfqg, pos, n, &cfqd->cfqg_list, cfqd_node) { | |
1078 | /* | |
1079 | * If cgroup removal path got to blk_group first and removed | |
1080 | * it from cgroup list, then it will take care of destroying | |
1081 | * cfqg also. | |
1082 | */ | |
e98ef89b | 1083 | if (!cfq_blkiocg_del_blkio_group(&cfqg->blkg)) |
b1c35769 VG |
1084 | cfq_destroy_cfqg(cfqd, cfqg); |
1085 | } | |
25fb5169 | 1086 | } |
b1c35769 VG |
1087 | |
1088 | /* | |
1089 | * Blk cgroup controller notification saying that blkio_group object is being | |
1090 | * delinked as associated cgroup object is going away. That also means that | |
1091 | * no new IO will come in this group. So get rid of this group as soon as | |
1092 | * any pending IO in the group is finished. | |
1093 | * | |
1094 | * This function is called under rcu_read_lock(). key is the rcu protected | |
1095 | * pointer. That means "key" is a valid cfq_data pointer as long as we are rcu | |
1096 | * read lock. | |
1097 | * | |
1098 | * "key" was fetched from blkio_group under blkio_cgroup->lock. That means | |
1099 | * it should not be NULL as even if elevator was exiting, cgroup deltion | |
1100 | * path got to it first. | |
1101 | */ | |
1102 | void cfq_unlink_blkio_group(void *key, struct blkio_group *blkg) | |
1103 | { | |
1104 | unsigned long flags; | |
1105 | struct cfq_data *cfqd = key; | |
1106 | ||
1107 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
1108 | cfq_destroy_cfqg(cfqd, cfqg_of_blkg(blkg)); | |
1109 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
1110 | } | |
1111 | ||
25fb5169 VG |
1112 | #else /* GROUP_IOSCHED */ |
1113 | static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd, int create) | |
1114 | { | |
1115 | return &cfqd->root_group; | |
1116 | } | |
7f1dc8a2 VG |
1117 | |
1118 | static inline struct cfq_group *cfq_ref_get_cfqg(struct cfq_group *cfqg) | |
1119 | { | |
50eaeb32 | 1120 | return cfqg; |
7f1dc8a2 VG |
1121 | } |
1122 | ||
25fb5169 VG |
1123 | static inline void |
1124 | cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) { | |
1125 | cfqq->cfqg = cfqg; | |
1126 | } | |
1127 | ||
b1c35769 VG |
1128 | static void cfq_release_cfq_groups(struct cfq_data *cfqd) {} |
1129 | static inline void cfq_put_cfqg(struct cfq_group *cfqg) {} | |
1130 | ||
25fb5169 VG |
1131 | #endif /* GROUP_IOSCHED */ |
1132 | ||
498d3aa2 | 1133 | /* |
c0324a02 | 1134 | * The cfqd->service_trees holds all pending cfq_queue's that have |
498d3aa2 JA |
1135 | * requests waiting to be processed. It is sorted in the order that |
1136 | * we will service the queues. | |
1137 | */ | |
a36e71f9 | 1138 | static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
a6151c3a | 1139 | bool add_front) |
d9e7620e | 1140 | { |
0871714e JA |
1141 | struct rb_node **p, *parent; |
1142 | struct cfq_queue *__cfqq; | |
d9e7620e | 1143 | unsigned long rb_key; |
c0324a02 | 1144 | struct cfq_rb_root *service_tree; |
498d3aa2 | 1145 | int left; |
dae739eb | 1146 | int new_cfqq = 1; |
ae30c286 VG |
1147 | int group_changed = 0; |
1148 | ||
1149 | #ifdef CONFIG_CFQ_GROUP_IOSCHED | |
1150 | if (!cfqd->cfq_group_isolation | |
1151 | && cfqq_type(cfqq) == SYNC_NOIDLE_WORKLOAD | |
1152 | && cfqq->cfqg && cfqq->cfqg != &cfqd->root_group) { | |
1153 | /* Move this cfq to root group */ | |
1154 | cfq_log_cfqq(cfqd, cfqq, "moving to root group"); | |
1155 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) | |
1156 | cfq_group_service_tree_del(cfqd, cfqq->cfqg); | |
1157 | cfqq->orig_cfqg = cfqq->cfqg; | |
1158 | cfqq->cfqg = &cfqd->root_group; | |
1159 | atomic_inc(&cfqd->root_group.ref); | |
1160 | group_changed = 1; | |
1161 | } else if (!cfqd->cfq_group_isolation | |
1162 | && cfqq_type(cfqq) == SYNC_WORKLOAD && cfqq->orig_cfqg) { | |
1163 | /* cfqq is sequential now needs to go to its original group */ | |
1164 | BUG_ON(cfqq->cfqg != &cfqd->root_group); | |
1165 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) | |
1166 | cfq_group_service_tree_del(cfqd, cfqq->cfqg); | |
1167 | cfq_put_cfqg(cfqq->cfqg); | |
1168 | cfqq->cfqg = cfqq->orig_cfqg; | |
1169 | cfqq->orig_cfqg = NULL; | |
1170 | group_changed = 1; | |
1171 | cfq_log_cfqq(cfqd, cfqq, "moved to origin group"); | |
1172 | } | |
1173 | #endif | |
d9e7620e | 1174 | |
cdb16e8f | 1175 | service_tree = service_tree_for(cfqq->cfqg, cfqq_prio(cfqq), |
65b32a57 | 1176 | cfqq_type(cfqq)); |
0871714e JA |
1177 | if (cfq_class_idle(cfqq)) { |
1178 | rb_key = CFQ_IDLE_DELAY; | |
aa6f6a3d | 1179 | parent = rb_last(&service_tree->rb); |
0871714e JA |
1180 | if (parent && parent != &cfqq->rb_node) { |
1181 | __cfqq = rb_entry(parent, struct cfq_queue, rb_node); | |
1182 | rb_key += __cfqq->rb_key; | |
1183 | } else | |
1184 | rb_key += jiffies; | |
1185 | } else if (!add_front) { | |
b9c8946b JA |
1186 | /* |
1187 | * Get our rb key offset. Subtract any residual slice | |
1188 | * value carried from last service. A negative resid | |
1189 | * count indicates slice overrun, and this should position | |
1190 | * the next service time further away in the tree. | |
1191 | */ | |
edd75ffd | 1192 | rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies; |
b9c8946b | 1193 | rb_key -= cfqq->slice_resid; |
edd75ffd | 1194 | cfqq->slice_resid = 0; |
48e025e6 CZ |
1195 | } else { |
1196 | rb_key = -HZ; | |
aa6f6a3d | 1197 | __cfqq = cfq_rb_first(service_tree); |
48e025e6 CZ |
1198 | rb_key += __cfqq ? __cfqq->rb_key : jiffies; |
1199 | } | |
1da177e4 | 1200 | |
d9e7620e | 1201 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) { |
dae739eb | 1202 | new_cfqq = 0; |
99f9628a | 1203 | /* |
d9e7620e | 1204 | * same position, nothing more to do |
99f9628a | 1205 | */ |
c0324a02 CZ |
1206 | if (rb_key == cfqq->rb_key && |
1207 | cfqq->service_tree == service_tree) | |
d9e7620e | 1208 | return; |
1da177e4 | 1209 | |
aa6f6a3d CZ |
1210 | cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree); |
1211 | cfqq->service_tree = NULL; | |
1da177e4 | 1212 | } |
d9e7620e | 1213 | |
498d3aa2 | 1214 | left = 1; |
0871714e | 1215 | parent = NULL; |
aa6f6a3d CZ |
1216 | cfqq->service_tree = service_tree; |
1217 | p = &service_tree->rb.rb_node; | |
d9e7620e | 1218 | while (*p) { |
67060e37 | 1219 | struct rb_node **n; |
cc09e299 | 1220 | |
d9e7620e JA |
1221 | parent = *p; |
1222 | __cfqq = rb_entry(parent, struct cfq_queue, rb_node); | |
1223 | ||
0c534e0a | 1224 | /* |
c0324a02 | 1225 | * sort by key, that represents service time. |
0c534e0a | 1226 | */ |
c0324a02 | 1227 | if (time_before(rb_key, __cfqq->rb_key)) |
67060e37 | 1228 | n = &(*p)->rb_left; |
c0324a02 | 1229 | else { |
67060e37 | 1230 | n = &(*p)->rb_right; |
cc09e299 | 1231 | left = 0; |
c0324a02 | 1232 | } |
67060e37 JA |
1233 | |
1234 | p = n; | |
d9e7620e JA |
1235 | } |
1236 | ||
cc09e299 | 1237 | if (left) |
aa6f6a3d | 1238 | service_tree->left = &cfqq->rb_node; |
cc09e299 | 1239 | |
d9e7620e JA |
1240 | cfqq->rb_key = rb_key; |
1241 | rb_link_node(&cfqq->rb_node, parent, p); | |
aa6f6a3d CZ |
1242 | rb_insert_color(&cfqq->rb_node, &service_tree->rb); |
1243 | service_tree->count++; | |
ae30c286 | 1244 | if ((add_front || !new_cfqq) && !group_changed) |
dae739eb | 1245 | return; |
1fa8f6d6 | 1246 | cfq_group_service_tree_add(cfqd, cfqq->cfqg); |
1da177e4 LT |
1247 | } |
1248 | ||
a36e71f9 | 1249 | static struct cfq_queue * |
f2d1f0ae JA |
1250 | cfq_prio_tree_lookup(struct cfq_data *cfqd, struct rb_root *root, |
1251 | sector_t sector, struct rb_node **ret_parent, | |
1252 | struct rb_node ***rb_link) | |
a36e71f9 | 1253 | { |
a36e71f9 JA |
1254 | struct rb_node **p, *parent; |
1255 | struct cfq_queue *cfqq = NULL; | |
1256 | ||
1257 | parent = NULL; | |
1258 | p = &root->rb_node; | |
1259 | while (*p) { | |
1260 | struct rb_node **n; | |
1261 | ||
1262 | parent = *p; | |
1263 | cfqq = rb_entry(parent, struct cfq_queue, p_node); | |
1264 | ||
1265 | /* | |
1266 | * Sort strictly based on sector. Smallest to the left, | |
1267 | * largest to the right. | |
1268 | */ | |
2e46e8b2 | 1269 | if (sector > blk_rq_pos(cfqq->next_rq)) |
a36e71f9 | 1270 | n = &(*p)->rb_right; |
2e46e8b2 | 1271 | else if (sector < blk_rq_pos(cfqq->next_rq)) |
a36e71f9 JA |
1272 | n = &(*p)->rb_left; |
1273 | else | |
1274 | break; | |
1275 | p = n; | |
3ac6c9f8 | 1276 | cfqq = NULL; |
a36e71f9 JA |
1277 | } |
1278 | ||
1279 | *ret_parent = parent; | |
1280 | if (rb_link) | |
1281 | *rb_link = p; | |
3ac6c9f8 | 1282 | return cfqq; |
a36e71f9 JA |
1283 | } |
1284 | ||
1285 | static void cfq_prio_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1286 | { | |
a36e71f9 JA |
1287 | struct rb_node **p, *parent; |
1288 | struct cfq_queue *__cfqq; | |
1289 | ||
f2d1f0ae JA |
1290 | if (cfqq->p_root) { |
1291 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
1292 | cfqq->p_root = NULL; | |
1293 | } | |
a36e71f9 JA |
1294 | |
1295 | if (cfq_class_idle(cfqq)) | |
1296 | return; | |
1297 | if (!cfqq->next_rq) | |
1298 | return; | |
1299 | ||
f2d1f0ae | 1300 | cfqq->p_root = &cfqd->prio_trees[cfqq->org_ioprio]; |
2e46e8b2 TH |
1301 | __cfqq = cfq_prio_tree_lookup(cfqd, cfqq->p_root, |
1302 | blk_rq_pos(cfqq->next_rq), &parent, &p); | |
3ac6c9f8 JA |
1303 | if (!__cfqq) { |
1304 | rb_link_node(&cfqq->p_node, parent, p); | |
f2d1f0ae JA |
1305 | rb_insert_color(&cfqq->p_node, cfqq->p_root); |
1306 | } else | |
1307 | cfqq->p_root = NULL; | |
a36e71f9 JA |
1308 | } |
1309 | ||
498d3aa2 JA |
1310 | /* |
1311 | * Update cfqq's position in the service tree. | |
1312 | */ | |
edd75ffd | 1313 | static void cfq_resort_rr_list(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
6d048f53 | 1314 | { |
6d048f53 JA |
1315 | /* |
1316 | * Resorting requires the cfqq to be on the RR list already. | |
1317 | */ | |
a36e71f9 | 1318 | if (cfq_cfqq_on_rr(cfqq)) { |
edd75ffd | 1319 | cfq_service_tree_add(cfqd, cfqq, 0); |
a36e71f9 JA |
1320 | cfq_prio_tree_add(cfqd, cfqq); |
1321 | } | |
6d048f53 JA |
1322 | } |
1323 | ||
1da177e4 LT |
1324 | /* |
1325 | * add to busy list of queues for service, trying to be fair in ordering | |
22e2c507 | 1326 | * the pending list according to last request service |
1da177e4 | 1327 | */ |
febffd61 | 1328 | static void cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 1329 | { |
7b679138 | 1330 | cfq_log_cfqq(cfqd, cfqq, "add_to_rr"); |
3b18152c JA |
1331 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
1332 | cfq_mark_cfqq_on_rr(cfqq); | |
1da177e4 LT |
1333 | cfqd->busy_queues++; |
1334 | ||
edd75ffd | 1335 | cfq_resort_rr_list(cfqd, cfqq); |
1da177e4 LT |
1336 | } |
1337 | ||
498d3aa2 JA |
1338 | /* |
1339 | * Called when the cfqq no longer has requests pending, remove it from | |
1340 | * the service tree. | |
1341 | */ | |
febffd61 | 1342 | static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 1343 | { |
7b679138 | 1344 | cfq_log_cfqq(cfqd, cfqq, "del_from_rr"); |
3b18152c JA |
1345 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
1346 | cfq_clear_cfqq_on_rr(cfqq); | |
1da177e4 | 1347 | |
aa6f6a3d CZ |
1348 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) { |
1349 | cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree); | |
1350 | cfqq->service_tree = NULL; | |
1351 | } | |
f2d1f0ae JA |
1352 | if (cfqq->p_root) { |
1353 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
1354 | cfqq->p_root = NULL; | |
1355 | } | |
d9e7620e | 1356 | |
1fa8f6d6 | 1357 | cfq_group_service_tree_del(cfqd, cfqq->cfqg); |
1da177e4 LT |
1358 | BUG_ON(!cfqd->busy_queues); |
1359 | cfqd->busy_queues--; | |
1360 | } | |
1361 | ||
1362 | /* | |
1363 | * rb tree support functions | |
1364 | */ | |
febffd61 | 1365 | static void cfq_del_rq_rb(struct request *rq) |
1da177e4 | 1366 | { |
5e705374 | 1367 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
5e705374 | 1368 | const int sync = rq_is_sync(rq); |
1da177e4 | 1369 | |
b4878f24 JA |
1370 | BUG_ON(!cfqq->queued[sync]); |
1371 | cfqq->queued[sync]--; | |
1da177e4 | 1372 | |
5e705374 | 1373 | elv_rb_del(&cfqq->sort_list, rq); |
1da177e4 | 1374 | |
f04a6424 VG |
1375 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) { |
1376 | /* | |
1377 | * Queue will be deleted from service tree when we actually | |
1378 | * expire it later. Right now just remove it from prio tree | |
1379 | * as it is empty. | |
1380 | */ | |
1381 | if (cfqq->p_root) { | |
1382 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
1383 | cfqq->p_root = NULL; | |
1384 | } | |
1385 | } | |
1da177e4 LT |
1386 | } |
1387 | ||
5e705374 | 1388 | static void cfq_add_rq_rb(struct request *rq) |
1da177e4 | 1389 | { |
5e705374 | 1390 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
1da177e4 | 1391 | struct cfq_data *cfqd = cfqq->cfqd; |
a36e71f9 | 1392 | struct request *__alias, *prev; |
1da177e4 | 1393 | |
5380a101 | 1394 | cfqq->queued[rq_is_sync(rq)]++; |
1da177e4 LT |
1395 | |
1396 | /* | |
1397 | * looks a little odd, but the first insert might return an alias. | |
1398 | * if that happens, put the alias on the dispatch list | |
1399 | */ | |
21183b07 | 1400 | while ((__alias = elv_rb_add(&cfqq->sort_list, rq)) != NULL) |
5e705374 | 1401 | cfq_dispatch_insert(cfqd->queue, __alias); |
5fccbf61 JA |
1402 | |
1403 | if (!cfq_cfqq_on_rr(cfqq)) | |
1404 | cfq_add_cfqq_rr(cfqd, cfqq); | |
5044eed4 JA |
1405 | |
1406 | /* | |
1407 | * check if this request is a better next-serve candidate | |
1408 | */ | |
a36e71f9 | 1409 | prev = cfqq->next_rq; |
cf7c25cf | 1410 | cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq, cfqd->last_position); |
a36e71f9 JA |
1411 | |
1412 | /* | |
1413 | * adjust priority tree position, if ->next_rq changes | |
1414 | */ | |
1415 | if (prev != cfqq->next_rq) | |
1416 | cfq_prio_tree_add(cfqd, cfqq); | |
1417 | ||
5044eed4 | 1418 | BUG_ON(!cfqq->next_rq); |
1da177e4 LT |
1419 | } |
1420 | ||
febffd61 | 1421 | static void cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq) |
1da177e4 | 1422 | { |
5380a101 JA |
1423 | elv_rb_del(&cfqq->sort_list, rq); |
1424 | cfqq->queued[rq_is_sync(rq)]--; | |
e98ef89b VG |
1425 | cfq_blkiocg_update_io_remove_stats(&(RQ_CFQG(rq))->blkg, |
1426 | rq_data_dir(rq), rq_is_sync(rq)); | |
5e705374 | 1427 | cfq_add_rq_rb(rq); |
e98ef89b | 1428 | cfq_blkiocg_update_io_add_stats(&(RQ_CFQG(rq))->blkg, |
7f1dc8a2 VG |
1429 | &cfqq->cfqd->serving_group->blkg, rq_data_dir(rq), |
1430 | rq_is_sync(rq)); | |
1da177e4 LT |
1431 | } |
1432 | ||
206dc69b JA |
1433 | static struct request * |
1434 | cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio) | |
1da177e4 | 1435 | { |
206dc69b | 1436 | struct task_struct *tsk = current; |
91fac317 | 1437 | struct cfq_io_context *cic; |
206dc69b | 1438 | struct cfq_queue *cfqq; |
1da177e4 | 1439 | |
4ac845a2 | 1440 | cic = cfq_cic_lookup(cfqd, tsk->io_context); |
91fac317 VT |
1441 | if (!cic) |
1442 | return NULL; | |
1443 | ||
1444 | cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); | |
89850f7e JA |
1445 | if (cfqq) { |
1446 | sector_t sector = bio->bi_sector + bio_sectors(bio); | |
1447 | ||
21183b07 | 1448 | return elv_rb_find(&cfqq->sort_list, sector); |
89850f7e | 1449 | } |
1da177e4 | 1450 | |
1da177e4 LT |
1451 | return NULL; |
1452 | } | |
1453 | ||
165125e1 | 1454 | static void cfq_activate_request(struct request_queue *q, struct request *rq) |
1da177e4 | 1455 | { |
22e2c507 | 1456 | struct cfq_data *cfqd = q->elevator->elevator_data; |
3b18152c | 1457 | |
53c583d2 | 1458 | cfqd->rq_in_driver++; |
7b679138 | 1459 | cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "activate rq, drv=%d", |
53c583d2 | 1460 | cfqd->rq_in_driver); |
25776e35 | 1461 | |
5b93629b | 1462 | cfqd->last_position = blk_rq_pos(rq) + blk_rq_sectors(rq); |
1da177e4 LT |
1463 | } |
1464 | ||
165125e1 | 1465 | static void cfq_deactivate_request(struct request_queue *q, struct request *rq) |
1da177e4 | 1466 | { |
b4878f24 JA |
1467 | struct cfq_data *cfqd = q->elevator->elevator_data; |
1468 | ||
53c583d2 CZ |
1469 | WARN_ON(!cfqd->rq_in_driver); |
1470 | cfqd->rq_in_driver--; | |
7b679138 | 1471 | cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "deactivate rq, drv=%d", |
53c583d2 | 1472 | cfqd->rq_in_driver); |
1da177e4 LT |
1473 | } |
1474 | ||
b4878f24 | 1475 | static void cfq_remove_request(struct request *rq) |
1da177e4 | 1476 | { |
5e705374 | 1477 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
21183b07 | 1478 | |
5e705374 JA |
1479 | if (cfqq->next_rq == rq) |
1480 | cfqq->next_rq = cfq_find_next_rq(cfqq->cfqd, cfqq, rq); | |
1da177e4 | 1481 | |
b4878f24 | 1482 | list_del_init(&rq->queuelist); |
5e705374 | 1483 | cfq_del_rq_rb(rq); |
374f84ac | 1484 | |
45333d5a | 1485 | cfqq->cfqd->rq_queued--; |
e98ef89b VG |
1486 | cfq_blkiocg_update_io_remove_stats(&(RQ_CFQG(rq))->blkg, |
1487 | rq_data_dir(rq), rq_is_sync(rq)); | |
7b6d91da | 1488 | if (rq->cmd_flags & REQ_META) { |
374f84ac JA |
1489 | WARN_ON(!cfqq->meta_pending); |
1490 | cfqq->meta_pending--; | |
1491 | } | |
1da177e4 LT |
1492 | } |
1493 | ||
165125e1 JA |
1494 | static int cfq_merge(struct request_queue *q, struct request **req, |
1495 | struct bio *bio) | |
1da177e4 LT |
1496 | { |
1497 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1498 | struct request *__rq; | |
1da177e4 | 1499 | |
206dc69b | 1500 | __rq = cfq_find_rq_fmerge(cfqd, bio); |
22e2c507 | 1501 | if (__rq && elv_rq_merge_ok(__rq, bio)) { |
9817064b JA |
1502 | *req = __rq; |
1503 | return ELEVATOR_FRONT_MERGE; | |
1da177e4 LT |
1504 | } |
1505 | ||
1506 | return ELEVATOR_NO_MERGE; | |
1da177e4 LT |
1507 | } |
1508 | ||
165125e1 | 1509 | static void cfq_merged_request(struct request_queue *q, struct request *req, |
21183b07 | 1510 | int type) |
1da177e4 | 1511 | { |
21183b07 | 1512 | if (type == ELEVATOR_FRONT_MERGE) { |
5e705374 | 1513 | struct cfq_queue *cfqq = RQ_CFQQ(req); |
1da177e4 | 1514 | |
5e705374 | 1515 | cfq_reposition_rq_rb(cfqq, req); |
1da177e4 | 1516 | } |
1da177e4 LT |
1517 | } |
1518 | ||
812d4026 DS |
1519 | static void cfq_bio_merged(struct request_queue *q, struct request *req, |
1520 | struct bio *bio) | |
1521 | { | |
e98ef89b VG |
1522 | cfq_blkiocg_update_io_merged_stats(&(RQ_CFQG(req))->blkg, |
1523 | bio_data_dir(bio), cfq_bio_sync(bio)); | |
812d4026 DS |
1524 | } |
1525 | ||
1da177e4 | 1526 | static void |
165125e1 | 1527 | cfq_merged_requests(struct request_queue *q, struct request *rq, |
1da177e4 LT |
1528 | struct request *next) |
1529 | { | |
cf7c25cf | 1530 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 JA |
1531 | /* |
1532 | * reposition in fifo if next is older than rq | |
1533 | */ | |
1534 | if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && | |
30996f40 | 1535 | time_before(rq_fifo_time(next), rq_fifo_time(rq))) { |
22e2c507 | 1536 | list_move(&rq->queuelist, &next->queuelist); |
30996f40 JA |
1537 | rq_set_fifo_time(rq, rq_fifo_time(next)); |
1538 | } | |
22e2c507 | 1539 | |
cf7c25cf CZ |
1540 | if (cfqq->next_rq == next) |
1541 | cfqq->next_rq = rq; | |
b4878f24 | 1542 | cfq_remove_request(next); |
e98ef89b VG |
1543 | cfq_blkiocg_update_io_merged_stats(&(RQ_CFQG(rq))->blkg, |
1544 | rq_data_dir(next), rq_is_sync(next)); | |
22e2c507 JA |
1545 | } |
1546 | ||
165125e1 | 1547 | static int cfq_allow_merge(struct request_queue *q, struct request *rq, |
da775265 JA |
1548 | struct bio *bio) |
1549 | { | |
1550 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
91fac317 | 1551 | struct cfq_io_context *cic; |
da775265 | 1552 | struct cfq_queue *cfqq; |
da775265 JA |
1553 | |
1554 | /* | |
ec8acb69 | 1555 | * Disallow merge of a sync bio into an async request. |
da775265 | 1556 | */ |
91fac317 | 1557 | if (cfq_bio_sync(bio) && !rq_is_sync(rq)) |
a6151c3a | 1558 | return false; |
da775265 JA |
1559 | |
1560 | /* | |
719d3402 JA |
1561 | * Lookup the cfqq that this bio will be queued with. Allow |
1562 | * merge only if rq is queued there. | |
da775265 | 1563 | */ |
4ac845a2 | 1564 | cic = cfq_cic_lookup(cfqd, current->io_context); |
91fac317 | 1565 | if (!cic) |
a6151c3a | 1566 | return false; |
719d3402 | 1567 | |
91fac317 | 1568 | cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); |
a6151c3a | 1569 | return cfqq == RQ_CFQQ(rq); |
da775265 JA |
1570 | } |
1571 | ||
812df48d DS |
1572 | static inline void cfq_del_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1573 | { | |
1574 | del_timer(&cfqd->idle_slice_timer); | |
e98ef89b | 1575 | cfq_blkiocg_update_idle_time_stats(&cfqq->cfqg->blkg); |
812df48d DS |
1576 | } |
1577 | ||
febffd61 JA |
1578 | static void __cfq_set_active_queue(struct cfq_data *cfqd, |
1579 | struct cfq_queue *cfqq) | |
22e2c507 JA |
1580 | { |
1581 | if (cfqq) { | |
b1ffe737 DS |
1582 | cfq_log_cfqq(cfqd, cfqq, "set_active wl_prio:%d wl_type:%d", |
1583 | cfqd->serving_prio, cfqd->serving_type); | |
e98ef89b | 1584 | cfq_blkiocg_update_avg_queue_size_stats(&cfqq->cfqg->blkg); |
dae739eb VG |
1585 | cfqq->slice_start = 0; |
1586 | cfqq->dispatch_start = jiffies; | |
f75edf2d | 1587 | cfqq->allocated_slice = 0; |
22e2c507 | 1588 | cfqq->slice_end = 0; |
2f5cb738 JA |
1589 | cfqq->slice_dispatch = 0; |
1590 | ||
2f5cb738 | 1591 | cfq_clear_cfqq_wait_request(cfqq); |
b029195d | 1592 | cfq_clear_cfqq_must_dispatch(cfqq); |
3b18152c JA |
1593 | cfq_clear_cfqq_must_alloc_slice(cfqq); |
1594 | cfq_clear_cfqq_fifo_expire(cfqq); | |
44f7c160 | 1595 | cfq_mark_cfqq_slice_new(cfqq); |
2f5cb738 | 1596 | |
812df48d | 1597 | cfq_del_timer(cfqd, cfqq); |
22e2c507 JA |
1598 | } |
1599 | ||
1600 | cfqd->active_queue = cfqq; | |
1601 | } | |
1602 | ||
7b14e3b5 JA |
1603 | /* |
1604 | * current cfqq expired its slice (or was too idle), select new one | |
1605 | */ | |
1606 | static void | |
1607 | __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
e5ff082e | 1608 | bool timed_out) |
7b14e3b5 | 1609 | { |
7b679138 JA |
1610 | cfq_log_cfqq(cfqd, cfqq, "slice expired t=%d", timed_out); |
1611 | ||
7b14e3b5 | 1612 | if (cfq_cfqq_wait_request(cfqq)) |
812df48d | 1613 | cfq_del_timer(cfqd, cfqq); |
7b14e3b5 | 1614 | |
7b14e3b5 | 1615 | cfq_clear_cfqq_wait_request(cfqq); |
f75edf2d | 1616 | cfq_clear_cfqq_wait_busy(cfqq); |
7b14e3b5 | 1617 | |
ae54abed SL |
1618 | /* |
1619 | * If this cfqq is shared between multiple processes, check to | |
1620 | * make sure that those processes are still issuing I/Os within | |
1621 | * the mean seek distance. If not, it may be time to break the | |
1622 | * queues apart again. | |
1623 | */ | |
1624 | if (cfq_cfqq_coop(cfqq) && CFQQ_SEEKY(cfqq)) | |
1625 | cfq_mark_cfqq_split_coop(cfqq); | |
1626 | ||
7b14e3b5 | 1627 | /* |
6084cdda | 1628 | * store what was left of this slice, if the queue idled/timed out |
7b14e3b5 | 1629 | */ |
7b679138 | 1630 | if (timed_out && !cfq_cfqq_slice_new(cfqq)) { |
c5b680f3 | 1631 | cfqq->slice_resid = cfqq->slice_end - jiffies; |
7b679138 JA |
1632 | cfq_log_cfqq(cfqd, cfqq, "resid=%ld", cfqq->slice_resid); |
1633 | } | |
7b14e3b5 | 1634 | |
e5ff082e | 1635 | cfq_group_served(cfqd, cfqq->cfqg, cfqq); |
dae739eb | 1636 | |
f04a6424 VG |
1637 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) |
1638 | cfq_del_cfqq_rr(cfqd, cfqq); | |
1639 | ||
edd75ffd | 1640 | cfq_resort_rr_list(cfqd, cfqq); |
7b14e3b5 JA |
1641 | |
1642 | if (cfqq == cfqd->active_queue) | |
1643 | cfqd->active_queue = NULL; | |
1644 | ||
dae739eb VG |
1645 | if (&cfqq->cfqg->rb_node == cfqd->grp_service_tree.active) |
1646 | cfqd->grp_service_tree.active = NULL; | |
1647 | ||
7b14e3b5 JA |
1648 | if (cfqd->active_cic) { |
1649 | put_io_context(cfqd->active_cic->ioc); | |
1650 | cfqd->active_cic = NULL; | |
1651 | } | |
7b14e3b5 JA |
1652 | } |
1653 | ||
e5ff082e | 1654 | static inline void cfq_slice_expired(struct cfq_data *cfqd, bool timed_out) |
7b14e3b5 JA |
1655 | { |
1656 | struct cfq_queue *cfqq = cfqd->active_queue; | |
1657 | ||
1658 | if (cfqq) | |
e5ff082e | 1659 | __cfq_slice_expired(cfqd, cfqq, timed_out); |
7b14e3b5 JA |
1660 | } |
1661 | ||
498d3aa2 JA |
1662 | /* |
1663 | * Get next queue for service. Unless we have a queue preemption, | |
1664 | * we'll simply select the first cfqq in the service tree. | |
1665 | */ | |
6d048f53 | 1666 | static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd) |
22e2c507 | 1667 | { |
c0324a02 | 1668 | struct cfq_rb_root *service_tree = |
cdb16e8f | 1669 | service_tree_for(cfqd->serving_group, cfqd->serving_prio, |
65b32a57 | 1670 | cfqd->serving_type); |
d9e7620e | 1671 | |
f04a6424 VG |
1672 | if (!cfqd->rq_queued) |
1673 | return NULL; | |
1674 | ||
1fa8f6d6 VG |
1675 | /* There is nothing to dispatch */ |
1676 | if (!service_tree) | |
1677 | return NULL; | |
c0324a02 CZ |
1678 | if (RB_EMPTY_ROOT(&service_tree->rb)) |
1679 | return NULL; | |
1680 | return cfq_rb_first(service_tree); | |
6d048f53 JA |
1681 | } |
1682 | ||
f04a6424 VG |
1683 | static struct cfq_queue *cfq_get_next_queue_forced(struct cfq_data *cfqd) |
1684 | { | |
25fb5169 | 1685 | struct cfq_group *cfqg; |
f04a6424 VG |
1686 | struct cfq_queue *cfqq; |
1687 | int i, j; | |
1688 | struct cfq_rb_root *st; | |
1689 | ||
1690 | if (!cfqd->rq_queued) | |
1691 | return NULL; | |
1692 | ||
25fb5169 VG |
1693 | cfqg = cfq_get_next_cfqg(cfqd); |
1694 | if (!cfqg) | |
1695 | return NULL; | |
1696 | ||
f04a6424 VG |
1697 | for_each_cfqg_st(cfqg, i, j, st) |
1698 | if ((cfqq = cfq_rb_first(st)) != NULL) | |
1699 | return cfqq; | |
1700 | return NULL; | |
1701 | } | |
1702 | ||
498d3aa2 JA |
1703 | /* |
1704 | * Get and set a new active queue for service. | |
1705 | */ | |
a36e71f9 JA |
1706 | static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd, |
1707 | struct cfq_queue *cfqq) | |
6d048f53 | 1708 | { |
e00ef799 | 1709 | if (!cfqq) |
a36e71f9 | 1710 | cfqq = cfq_get_next_queue(cfqd); |
6d048f53 | 1711 | |
22e2c507 | 1712 | __cfq_set_active_queue(cfqd, cfqq); |
3b18152c | 1713 | return cfqq; |
22e2c507 JA |
1714 | } |
1715 | ||
d9e7620e JA |
1716 | static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd, |
1717 | struct request *rq) | |
1718 | { | |
83096ebf TH |
1719 | if (blk_rq_pos(rq) >= cfqd->last_position) |
1720 | return blk_rq_pos(rq) - cfqd->last_position; | |
d9e7620e | 1721 | else |
83096ebf | 1722 | return cfqd->last_position - blk_rq_pos(rq); |
d9e7620e JA |
1723 | } |
1724 | ||
b2c18e1e | 1725 | static inline int cfq_rq_close(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
e9ce335d | 1726 | struct request *rq) |
6d048f53 | 1727 | { |
e9ce335d | 1728 | return cfq_dist_from_last(cfqd, rq) <= CFQQ_CLOSE_THR; |
6d048f53 JA |
1729 | } |
1730 | ||
a36e71f9 JA |
1731 | static struct cfq_queue *cfqq_close(struct cfq_data *cfqd, |
1732 | struct cfq_queue *cur_cfqq) | |
1733 | { | |
f2d1f0ae | 1734 | struct rb_root *root = &cfqd->prio_trees[cur_cfqq->org_ioprio]; |
a36e71f9 JA |
1735 | struct rb_node *parent, *node; |
1736 | struct cfq_queue *__cfqq; | |
1737 | sector_t sector = cfqd->last_position; | |
1738 | ||
1739 | if (RB_EMPTY_ROOT(root)) | |
1740 | return NULL; | |
1741 | ||
1742 | /* | |
1743 | * First, if we find a request starting at the end of the last | |
1744 | * request, choose it. | |
1745 | */ | |
f2d1f0ae | 1746 | __cfqq = cfq_prio_tree_lookup(cfqd, root, sector, &parent, NULL); |
a36e71f9 JA |
1747 | if (__cfqq) |
1748 | return __cfqq; | |
1749 | ||
1750 | /* | |
1751 | * If the exact sector wasn't found, the parent of the NULL leaf | |
1752 | * will contain the closest sector. | |
1753 | */ | |
1754 | __cfqq = rb_entry(parent, struct cfq_queue, p_node); | |
e9ce335d | 1755 | if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq)) |
a36e71f9 JA |
1756 | return __cfqq; |
1757 | ||
2e46e8b2 | 1758 | if (blk_rq_pos(__cfqq->next_rq) < sector) |
a36e71f9 JA |
1759 | node = rb_next(&__cfqq->p_node); |
1760 | else | |
1761 | node = rb_prev(&__cfqq->p_node); | |
1762 | if (!node) | |
1763 | return NULL; | |
1764 | ||
1765 | __cfqq = rb_entry(node, struct cfq_queue, p_node); | |
e9ce335d | 1766 | if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq)) |
a36e71f9 JA |
1767 | return __cfqq; |
1768 | ||
1769 | return NULL; | |
1770 | } | |
1771 | ||
1772 | /* | |
1773 | * cfqd - obvious | |
1774 | * cur_cfqq - passed in so that we don't decide that the current queue is | |
1775 | * closely cooperating with itself. | |
1776 | * | |
1777 | * So, basically we're assuming that that cur_cfqq has dispatched at least | |
1778 | * one request, and that cfqd->last_position reflects a position on the disk | |
1779 | * associated with the I/O issued by cur_cfqq. I'm not sure this is a valid | |
1780 | * assumption. | |
1781 | */ | |
1782 | static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd, | |
b3b6d040 | 1783 | struct cfq_queue *cur_cfqq) |
6d048f53 | 1784 | { |
a36e71f9 JA |
1785 | struct cfq_queue *cfqq; |
1786 | ||
39c01b21 DS |
1787 | if (cfq_class_idle(cur_cfqq)) |
1788 | return NULL; | |
e6c5bc73 JM |
1789 | if (!cfq_cfqq_sync(cur_cfqq)) |
1790 | return NULL; | |
1791 | if (CFQQ_SEEKY(cur_cfqq)) | |
1792 | return NULL; | |
1793 | ||
b9d8f4c7 GJ |
1794 | /* |
1795 | * Don't search priority tree if it's the only queue in the group. | |
1796 | */ | |
1797 | if (cur_cfqq->cfqg->nr_cfqq == 1) | |
1798 | return NULL; | |
1799 | ||
6d048f53 | 1800 | /* |
d9e7620e JA |
1801 | * We should notice if some of the queues are cooperating, eg |
1802 | * working closely on the same area of the disk. In that case, | |
1803 | * we can group them together and don't waste time idling. | |
6d048f53 | 1804 | */ |
a36e71f9 JA |
1805 | cfqq = cfqq_close(cfqd, cur_cfqq); |
1806 | if (!cfqq) | |
1807 | return NULL; | |
1808 | ||
8682e1f1 VG |
1809 | /* If new queue belongs to different cfq_group, don't choose it */ |
1810 | if (cur_cfqq->cfqg != cfqq->cfqg) | |
1811 | return NULL; | |
1812 | ||
df5fe3e8 JM |
1813 | /* |
1814 | * It only makes sense to merge sync queues. | |
1815 | */ | |
1816 | if (!cfq_cfqq_sync(cfqq)) | |
1817 | return NULL; | |
e6c5bc73 JM |
1818 | if (CFQQ_SEEKY(cfqq)) |
1819 | return NULL; | |
df5fe3e8 | 1820 | |
c0324a02 CZ |
1821 | /* |
1822 | * Do not merge queues of different priority classes | |
1823 | */ | |
1824 | if (cfq_class_rt(cfqq) != cfq_class_rt(cur_cfqq)) | |
1825 | return NULL; | |
1826 | ||
a36e71f9 | 1827 | return cfqq; |
6d048f53 JA |
1828 | } |
1829 | ||
a6d44e98 CZ |
1830 | /* |
1831 | * Determine whether we should enforce idle window for this queue. | |
1832 | */ | |
1833 | ||
1834 | static bool cfq_should_idle(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1835 | { | |
1836 | enum wl_prio_t prio = cfqq_prio(cfqq); | |
718eee05 | 1837 | struct cfq_rb_root *service_tree = cfqq->service_tree; |
a6d44e98 | 1838 | |
f04a6424 VG |
1839 | BUG_ON(!service_tree); |
1840 | BUG_ON(!service_tree->count); | |
1841 | ||
a6d44e98 CZ |
1842 | /* We never do for idle class queues. */ |
1843 | if (prio == IDLE_WORKLOAD) | |
1844 | return false; | |
1845 | ||
1846 | /* We do for queues that were marked with idle window flag. */ | |
3c764b7a SL |
1847 | if (cfq_cfqq_idle_window(cfqq) && |
1848 | !(blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag)) | |
a6d44e98 CZ |
1849 | return true; |
1850 | ||
1851 | /* | |
1852 | * Otherwise, we do only if they are the last ones | |
1853 | * in their service tree. | |
1854 | */ | |
b1ffe737 DS |
1855 | if (service_tree->count == 1 && cfq_cfqq_sync(cfqq)) |
1856 | return 1; | |
1857 | cfq_log_cfqq(cfqd, cfqq, "Not idling. st->count:%d", | |
1858 | service_tree->count); | |
1859 | return 0; | |
a6d44e98 CZ |
1860 | } |
1861 | ||
6d048f53 | 1862 | static void cfq_arm_slice_timer(struct cfq_data *cfqd) |
22e2c507 | 1863 | { |
1792669c | 1864 | struct cfq_queue *cfqq = cfqd->active_queue; |
206dc69b | 1865 | struct cfq_io_context *cic; |
7b14e3b5 JA |
1866 | unsigned long sl; |
1867 | ||
a68bbddb | 1868 | /* |
f7d7b7a7 JA |
1869 | * SSD device without seek penalty, disable idling. But only do so |
1870 | * for devices that support queuing, otherwise we still have a problem | |
1871 | * with sync vs async workloads. | |
a68bbddb | 1872 | */ |
f7d7b7a7 | 1873 | if (blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag) |
a68bbddb JA |
1874 | return; |
1875 | ||
dd67d051 | 1876 | WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list)); |
6d048f53 | 1877 | WARN_ON(cfq_cfqq_slice_new(cfqq)); |
22e2c507 JA |
1878 | |
1879 | /* | |
1880 | * idle is disabled, either manually or by past process history | |
1881 | */ | |
a6d44e98 | 1882 | if (!cfqd->cfq_slice_idle || !cfq_should_idle(cfqd, cfqq)) |
6d048f53 JA |
1883 | return; |
1884 | ||
7b679138 | 1885 | /* |
8e550632 | 1886 | * still active requests from this queue, don't idle |
7b679138 | 1887 | */ |
8e550632 | 1888 | if (cfqq->dispatched) |
7b679138 JA |
1889 | return; |
1890 | ||
22e2c507 JA |
1891 | /* |
1892 | * task has exited, don't wait | |
1893 | */ | |
206dc69b | 1894 | cic = cfqd->active_cic; |
66dac98e | 1895 | if (!cic || !atomic_read(&cic->ioc->nr_tasks)) |
6d048f53 JA |
1896 | return; |
1897 | ||
355b659c CZ |
1898 | /* |
1899 | * If our average think time is larger than the remaining time | |
1900 | * slice, then don't idle. This avoids overrunning the allotted | |
1901 | * time slice. | |
1902 | */ | |
1903 | if (sample_valid(cic->ttime_samples) && | |
b1ffe737 DS |
1904 | (cfqq->slice_end - jiffies < cic->ttime_mean)) { |
1905 | cfq_log_cfqq(cfqd, cfqq, "Not idling. think_time:%d", | |
1906 | cic->ttime_mean); | |
355b659c | 1907 | return; |
b1ffe737 | 1908 | } |
355b659c | 1909 | |
3b18152c | 1910 | cfq_mark_cfqq_wait_request(cfqq); |
22e2c507 | 1911 | |
6d048f53 | 1912 | sl = cfqd->cfq_slice_idle; |
206dc69b | 1913 | |
7b14e3b5 | 1914 | mod_timer(&cfqd->idle_slice_timer, jiffies + sl); |
e98ef89b | 1915 | cfq_blkiocg_update_set_idle_time_stats(&cfqq->cfqg->blkg); |
9481ffdc | 1916 | cfq_log_cfqq(cfqd, cfqq, "arm_idle: %lu", sl); |
1da177e4 LT |
1917 | } |
1918 | ||
498d3aa2 JA |
1919 | /* |
1920 | * Move request from internal lists to the request queue dispatch list. | |
1921 | */ | |
165125e1 | 1922 | static void cfq_dispatch_insert(struct request_queue *q, struct request *rq) |
1da177e4 | 1923 | { |
3ed9a296 | 1924 | struct cfq_data *cfqd = q->elevator->elevator_data; |
5e705374 | 1925 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 | 1926 | |
7b679138 JA |
1927 | cfq_log_cfqq(cfqd, cfqq, "dispatch_insert"); |
1928 | ||
06d21886 | 1929 | cfqq->next_rq = cfq_find_next_rq(cfqd, cfqq, rq); |
5380a101 | 1930 | cfq_remove_request(rq); |
6d048f53 | 1931 | cfqq->dispatched++; |
5380a101 | 1932 | elv_dispatch_sort(q, rq); |
3ed9a296 | 1933 | |
53c583d2 | 1934 | cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]++; |
e98ef89b | 1935 | cfq_blkiocg_update_dispatch_stats(&cfqq->cfqg->blkg, blk_rq_bytes(rq), |
84c124da | 1936 | rq_data_dir(rq), rq_is_sync(rq)); |
1da177e4 LT |
1937 | } |
1938 | ||
1939 | /* | |
1940 | * return expired entry, or NULL to just start from scratch in rbtree | |
1941 | */ | |
febffd61 | 1942 | static struct request *cfq_check_fifo(struct cfq_queue *cfqq) |
1da177e4 | 1943 | { |
30996f40 | 1944 | struct request *rq = NULL; |
1da177e4 | 1945 | |
3b18152c | 1946 | if (cfq_cfqq_fifo_expire(cfqq)) |
1da177e4 | 1947 | return NULL; |
cb887411 JA |
1948 | |
1949 | cfq_mark_cfqq_fifo_expire(cfqq); | |
1950 | ||
89850f7e JA |
1951 | if (list_empty(&cfqq->fifo)) |
1952 | return NULL; | |
1da177e4 | 1953 | |
89850f7e | 1954 | rq = rq_entry_fifo(cfqq->fifo.next); |
30996f40 | 1955 | if (time_before(jiffies, rq_fifo_time(rq))) |
7b679138 | 1956 | rq = NULL; |
1da177e4 | 1957 | |
30996f40 | 1958 | cfq_log_cfqq(cfqq->cfqd, cfqq, "fifo=%p", rq); |
6d048f53 | 1959 | return rq; |
1da177e4 LT |
1960 | } |
1961 | ||
22e2c507 JA |
1962 | static inline int |
1963 | cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1964 | { | |
1965 | const int base_rq = cfqd->cfq_slice_async_rq; | |
1da177e4 | 1966 | |
22e2c507 | 1967 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); |
1da177e4 | 1968 | |
22e2c507 | 1969 | return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio)); |
1da177e4 LT |
1970 | } |
1971 | ||
df5fe3e8 JM |
1972 | /* |
1973 | * Must be called with the queue_lock held. | |
1974 | */ | |
1975 | static int cfqq_process_refs(struct cfq_queue *cfqq) | |
1976 | { | |
1977 | int process_refs, io_refs; | |
1978 | ||
1979 | io_refs = cfqq->allocated[READ] + cfqq->allocated[WRITE]; | |
1980 | process_refs = atomic_read(&cfqq->ref) - io_refs; | |
1981 | BUG_ON(process_refs < 0); | |
1982 | return process_refs; | |
1983 | } | |
1984 | ||
1985 | static void cfq_setup_merge(struct cfq_queue *cfqq, struct cfq_queue *new_cfqq) | |
1986 | { | |
e6c5bc73 | 1987 | int process_refs, new_process_refs; |
df5fe3e8 JM |
1988 | struct cfq_queue *__cfqq; |
1989 | ||
c10b61f0 JM |
1990 | /* |
1991 | * If there are no process references on the new_cfqq, then it is | |
1992 | * unsafe to follow the ->new_cfqq chain as other cfqq's in the | |
1993 | * chain may have dropped their last reference (not just their | |
1994 | * last process reference). | |
1995 | */ | |
1996 | if (!cfqq_process_refs(new_cfqq)) | |
1997 | return; | |
1998 | ||
df5fe3e8 JM |
1999 | /* Avoid a circular list and skip interim queue merges */ |
2000 | while ((__cfqq = new_cfqq->new_cfqq)) { | |
2001 | if (__cfqq == cfqq) | |
2002 | return; | |
2003 | new_cfqq = __cfqq; | |
2004 | } | |
2005 | ||
2006 | process_refs = cfqq_process_refs(cfqq); | |
c10b61f0 | 2007 | new_process_refs = cfqq_process_refs(new_cfqq); |
df5fe3e8 JM |
2008 | /* |
2009 | * If the process for the cfqq has gone away, there is no | |
2010 | * sense in merging the queues. | |
2011 | */ | |
c10b61f0 | 2012 | if (process_refs == 0 || new_process_refs == 0) |
df5fe3e8 JM |
2013 | return; |
2014 | ||
e6c5bc73 JM |
2015 | /* |
2016 | * Merge in the direction of the lesser amount of work. | |
2017 | */ | |
e6c5bc73 JM |
2018 | if (new_process_refs >= process_refs) { |
2019 | cfqq->new_cfqq = new_cfqq; | |
2020 | atomic_add(process_refs, &new_cfqq->ref); | |
2021 | } else { | |
2022 | new_cfqq->new_cfqq = cfqq; | |
2023 | atomic_add(new_process_refs, &cfqq->ref); | |
2024 | } | |
df5fe3e8 JM |
2025 | } |
2026 | ||
cdb16e8f | 2027 | static enum wl_type_t cfq_choose_wl(struct cfq_data *cfqd, |
65b32a57 | 2028 | struct cfq_group *cfqg, enum wl_prio_t prio) |
718eee05 CZ |
2029 | { |
2030 | struct cfq_queue *queue; | |
2031 | int i; | |
2032 | bool key_valid = false; | |
2033 | unsigned long lowest_key = 0; | |
2034 | enum wl_type_t cur_best = SYNC_NOIDLE_WORKLOAD; | |
2035 | ||
65b32a57 VG |
2036 | for (i = 0; i <= SYNC_WORKLOAD; ++i) { |
2037 | /* select the one with lowest rb_key */ | |
2038 | queue = cfq_rb_first(service_tree_for(cfqg, prio, i)); | |
718eee05 CZ |
2039 | if (queue && |
2040 | (!key_valid || time_before(queue->rb_key, lowest_key))) { | |
2041 | lowest_key = queue->rb_key; | |
2042 | cur_best = i; | |
2043 | key_valid = true; | |
2044 | } | |
2045 | } | |
2046 | ||
2047 | return cur_best; | |
2048 | } | |
2049 | ||
cdb16e8f | 2050 | static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg) |
718eee05 | 2051 | { |
718eee05 CZ |
2052 | unsigned slice; |
2053 | unsigned count; | |
cdb16e8f | 2054 | struct cfq_rb_root *st; |
58ff82f3 | 2055 | unsigned group_slice; |
718eee05 | 2056 | |
1fa8f6d6 VG |
2057 | if (!cfqg) { |
2058 | cfqd->serving_prio = IDLE_WORKLOAD; | |
2059 | cfqd->workload_expires = jiffies + 1; | |
2060 | return; | |
2061 | } | |
2062 | ||
718eee05 | 2063 | /* Choose next priority. RT > BE > IDLE */ |
58ff82f3 | 2064 | if (cfq_group_busy_queues_wl(RT_WORKLOAD, cfqd, cfqg)) |
718eee05 | 2065 | cfqd->serving_prio = RT_WORKLOAD; |
58ff82f3 | 2066 | else if (cfq_group_busy_queues_wl(BE_WORKLOAD, cfqd, cfqg)) |
718eee05 CZ |
2067 | cfqd->serving_prio = BE_WORKLOAD; |
2068 | else { | |
2069 | cfqd->serving_prio = IDLE_WORKLOAD; | |
2070 | cfqd->workload_expires = jiffies + 1; | |
2071 | return; | |
2072 | } | |
2073 | ||
2074 | /* | |
2075 | * For RT and BE, we have to choose also the type | |
2076 | * (SYNC, SYNC_NOIDLE, ASYNC), and to compute a workload | |
2077 | * expiration time | |
2078 | */ | |
65b32a57 | 2079 | st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type); |
cdb16e8f | 2080 | count = st->count; |
718eee05 CZ |
2081 | |
2082 | /* | |
65b32a57 | 2083 | * check workload expiration, and that we still have other queues ready |
718eee05 | 2084 | */ |
65b32a57 | 2085 | if (count && !time_after(jiffies, cfqd->workload_expires)) |
718eee05 CZ |
2086 | return; |
2087 | ||
2088 | /* otherwise select new workload type */ | |
2089 | cfqd->serving_type = | |
65b32a57 VG |
2090 | cfq_choose_wl(cfqd, cfqg, cfqd->serving_prio); |
2091 | st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type); | |
cdb16e8f | 2092 | count = st->count; |
718eee05 CZ |
2093 | |
2094 | /* | |
2095 | * the workload slice is computed as a fraction of target latency | |
2096 | * proportional to the number of queues in that workload, over | |
2097 | * all the queues in the same priority class | |
2098 | */ | |
58ff82f3 VG |
2099 | group_slice = cfq_group_slice(cfqd, cfqg); |
2100 | ||
2101 | slice = group_slice * count / | |
2102 | max_t(unsigned, cfqg->busy_queues_avg[cfqd->serving_prio], | |
2103 | cfq_group_busy_queues_wl(cfqd->serving_prio, cfqd, cfqg)); | |
718eee05 | 2104 | |
f26bd1f0 VG |
2105 | if (cfqd->serving_type == ASYNC_WORKLOAD) { |
2106 | unsigned int tmp; | |
2107 | ||
2108 | /* | |
2109 | * Async queues are currently system wide. Just taking | |
2110 | * proportion of queues with-in same group will lead to higher | |
2111 | * async ratio system wide as generally root group is going | |
2112 | * to have higher weight. A more accurate thing would be to | |
2113 | * calculate system wide asnc/sync ratio. | |
2114 | */ | |
2115 | tmp = cfq_target_latency * cfqg_busy_async_queues(cfqd, cfqg); | |
2116 | tmp = tmp/cfqd->busy_queues; | |
2117 | slice = min_t(unsigned, slice, tmp); | |
2118 | ||
718eee05 CZ |
2119 | /* async workload slice is scaled down according to |
2120 | * the sync/async slice ratio. */ | |
2121 | slice = slice * cfqd->cfq_slice[0] / cfqd->cfq_slice[1]; | |
f26bd1f0 | 2122 | } else |
718eee05 CZ |
2123 | /* sync workload slice is at least 2 * cfq_slice_idle */ |
2124 | slice = max(slice, 2 * cfqd->cfq_slice_idle); | |
2125 | ||
2126 | slice = max_t(unsigned, slice, CFQ_MIN_TT); | |
b1ffe737 | 2127 | cfq_log(cfqd, "workload slice:%d", slice); |
718eee05 | 2128 | cfqd->workload_expires = jiffies + slice; |
8e550632 | 2129 | cfqd->noidle_tree_requires_idle = false; |
718eee05 CZ |
2130 | } |
2131 | ||
1fa8f6d6 VG |
2132 | static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd) |
2133 | { | |
2134 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
25bc6b07 | 2135 | struct cfq_group *cfqg; |
1fa8f6d6 VG |
2136 | |
2137 | if (RB_EMPTY_ROOT(&st->rb)) | |
2138 | return NULL; | |
25bc6b07 VG |
2139 | cfqg = cfq_rb_first_group(st); |
2140 | st->active = &cfqg->rb_node; | |
2141 | update_min_vdisktime(st); | |
2142 | return cfqg; | |
1fa8f6d6 VG |
2143 | } |
2144 | ||
cdb16e8f VG |
2145 | static void cfq_choose_cfqg(struct cfq_data *cfqd) |
2146 | { | |
1fa8f6d6 VG |
2147 | struct cfq_group *cfqg = cfq_get_next_cfqg(cfqd); |
2148 | ||
2149 | cfqd->serving_group = cfqg; | |
dae739eb VG |
2150 | |
2151 | /* Restore the workload type data */ | |
2152 | if (cfqg->saved_workload_slice) { | |
2153 | cfqd->workload_expires = jiffies + cfqg->saved_workload_slice; | |
2154 | cfqd->serving_type = cfqg->saved_workload; | |
2155 | cfqd->serving_prio = cfqg->saved_serving_prio; | |
66ae2919 GJ |
2156 | } else |
2157 | cfqd->workload_expires = jiffies - 1; | |
2158 | ||
1fa8f6d6 | 2159 | choose_service_tree(cfqd, cfqg); |
cdb16e8f VG |
2160 | } |
2161 | ||
22e2c507 | 2162 | /* |
498d3aa2 JA |
2163 | * Select a queue for service. If we have a current active queue, |
2164 | * check whether to continue servicing it, or retrieve and set a new one. | |
22e2c507 | 2165 | */ |
1b5ed5e1 | 2166 | static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) |
1da177e4 | 2167 | { |
a36e71f9 | 2168 | struct cfq_queue *cfqq, *new_cfqq = NULL; |
1da177e4 | 2169 | |
22e2c507 JA |
2170 | cfqq = cfqd->active_queue; |
2171 | if (!cfqq) | |
2172 | goto new_queue; | |
1da177e4 | 2173 | |
f04a6424 VG |
2174 | if (!cfqd->rq_queued) |
2175 | return NULL; | |
c244bb50 VG |
2176 | |
2177 | /* | |
2178 | * We were waiting for group to get backlogged. Expire the queue | |
2179 | */ | |
2180 | if (cfq_cfqq_wait_busy(cfqq) && !RB_EMPTY_ROOT(&cfqq->sort_list)) | |
2181 | goto expire; | |
2182 | ||
22e2c507 | 2183 | /* |
6d048f53 | 2184 | * The active queue has run out of time, expire it and select new. |
22e2c507 | 2185 | */ |
7667aa06 VG |
2186 | if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq)) { |
2187 | /* | |
2188 | * If slice had not expired at the completion of last request | |
2189 | * we might not have turned on wait_busy flag. Don't expire | |
2190 | * the queue yet. Allow the group to get backlogged. | |
2191 | * | |
2192 | * The very fact that we have used the slice, that means we | |
2193 | * have been idling all along on this queue and it should be | |
2194 | * ok to wait for this request to complete. | |
2195 | */ | |
82bbbf28 VG |
2196 | if (cfqq->cfqg->nr_cfqq == 1 && RB_EMPTY_ROOT(&cfqq->sort_list) |
2197 | && cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) { | |
2198 | cfqq = NULL; | |
7667aa06 | 2199 | goto keep_queue; |
82bbbf28 | 2200 | } else |
7667aa06 VG |
2201 | goto expire; |
2202 | } | |
1da177e4 | 2203 | |
22e2c507 | 2204 | /* |
6d048f53 JA |
2205 | * The active queue has requests and isn't expired, allow it to |
2206 | * dispatch. | |
22e2c507 | 2207 | */ |
dd67d051 | 2208 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
22e2c507 | 2209 | goto keep_queue; |
6d048f53 | 2210 | |
a36e71f9 JA |
2211 | /* |
2212 | * If another queue has a request waiting within our mean seek | |
2213 | * distance, let it run. The expire code will check for close | |
2214 | * cooperators and put the close queue at the front of the service | |
df5fe3e8 | 2215 | * tree. If possible, merge the expiring queue with the new cfqq. |
a36e71f9 | 2216 | */ |
b3b6d040 | 2217 | new_cfqq = cfq_close_cooperator(cfqd, cfqq); |
df5fe3e8 JM |
2218 | if (new_cfqq) { |
2219 | if (!cfqq->new_cfqq) | |
2220 | cfq_setup_merge(cfqq, new_cfqq); | |
a36e71f9 | 2221 | goto expire; |
df5fe3e8 | 2222 | } |
a36e71f9 | 2223 | |
6d048f53 JA |
2224 | /* |
2225 | * No requests pending. If the active queue still has requests in | |
2226 | * flight or is idling for a new request, allow either of these | |
2227 | * conditions to happen (or time out) before selecting a new queue. | |
2228 | */ | |
cc197479 | 2229 | if (timer_pending(&cfqd->idle_slice_timer) || |
a6d44e98 | 2230 | (cfqq->dispatched && cfq_should_idle(cfqd, cfqq))) { |
caaa5f9f JA |
2231 | cfqq = NULL; |
2232 | goto keep_queue; | |
22e2c507 JA |
2233 | } |
2234 | ||
3b18152c | 2235 | expire: |
e5ff082e | 2236 | cfq_slice_expired(cfqd, 0); |
3b18152c | 2237 | new_queue: |
718eee05 CZ |
2238 | /* |
2239 | * Current queue expired. Check if we have to switch to a new | |
2240 | * service tree | |
2241 | */ | |
2242 | if (!new_cfqq) | |
cdb16e8f | 2243 | cfq_choose_cfqg(cfqd); |
718eee05 | 2244 | |
a36e71f9 | 2245 | cfqq = cfq_set_active_queue(cfqd, new_cfqq); |
22e2c507 | 2246 | keep_queue: |
3b18152c | 2247 | return cfqq; |
22e2c507 JA |
2248 | } |
2249 | ||
febffd61 | 2250 | static int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq) |
d9e7620e JA |
2251 | { |
2252 | int dispatched = 0; | |
2253 | ||
2254 | while (cfqq->next_rq) { | |
2255 | cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq); | |
2256 | dispatched++; | |
2257 | } | |
2258 | ||
2259 | BUG_ON(!list_empty(&cfqq->fifo)); | |
f04a6424 VG |
2260 | |
2261 | /* By default cfqq is not expired if it is empty. Do it explicitly */ | |
e5ff082e | 2262 | __cfq_slice_expired(cfqq->cfqd, cfqq, 0); |
d9e7620e JA |
2263 | return dispatched; |
2264 | } | |
2265 | ||
498d3aa2 JA |
2266 | /* |
2267 | * Drain our current requests. Used for barriers and when switching | |
2268 | * io schedulers on-the-fly. | |
2269 | */ | |
d9e7620e | 2270 | static int cfq_forced_dispatch(struct cfq_data *cfqd) |
1b5ed5e1 | 2271 | { |
0871714e | 2272 | struct cfq_queue *cfqq; |
d9e7620e | 2273 | int dispatched = 0; |
cdb16e8f | 2274 | |
3440c49f | 2275 | /* Expire the timeslice of the current active queue first */ |
e5ff082e | 2276 | cfq_slice_expired(cfqd, 0); |
3440c49f DS |
2277 | while ((cfqq = cfq_get_next_queue_forced(cfqd)) != NULL) { |
2278 | __cfq_set_active_queue(cfqd, cfqq); | |
f04a6424 | 2279 | dispatched += __cfq_forced_dispatch_cfqq(cfqq); |
3440c49f | 2280 | } |
1b5ed5e1 | 2281 | |
1b5ed5e1 TH |
2282 | BUG_ON(cfqd->busy_queues); |
2283 | ||
6923715a | 2284 | cfq_log(cfqd, "forced_dispatch=%d", dispatched); |
1b5ed5e1 TH |
2285 | return dispatched; |
2286 | } | |
2287 | ||
abc3c744 SL |
2288 | static inline bool cfq_slice_used_soon(struct cfq_data *cfqd, |
2289 | struct cfq_queue *cfqq) | |
2290 | { | |
2291 | /* the queue hasn't finished any request, can't estimate */ | |
2292 | if (cfq_cfqq_slice_new(cfqq)) | |
2293 | return 1; | |
2294 | if (time_after(jiffies + cfqd->cfq_slice_idle * cfqq->dispatched, | |
2295 | cfqq->slice_end)) | |
2296 | return 1; | |
2297 | ||
2298 | return 0; | |
2299 | } | |
2300 | ||
0b182d61 | 2301 | static bool cfq_may_dispatch(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
2f5cb738 | 2302 | { |
2f5cb738 | 2303 | unsigned int max_dispatch; |
22e2c507 | 2304 | |
5ad531db JA |
2305 | /* |
2306 | * Drain async requests before we start sync IO | |
2307 | */ | |
53c583d2 | 2308 | if (cfq_should_idle(cfqd, cfqq) && cfqd->rq_in_flight[BLK_RW_ASYNC]) |
0b182d61 | 2309 | return false; |
5ad531db | 2310 | |
2f5cb738 JA |
2311 | /* |
2312 | * If this is an async queue and we have sync IO in flight, let it wait | |
2313 | */ | |
53c583d2 | 2314 | if (cfqd->rq_in_flight[BLK_RW_SYNC] && !cfq_cfqq_sync(cfqq)) |
0b182d61 | 2315 | return false; |
2f5cb738 | 2316 | |
abc3c744 | 2317 | max_dispatch = max_t(unsigned int, cfqd->cfq_quantum / 2, 1); |
2f5cb738 JA |
2318 | if (cfq_class_idle(cfqq)) |
2319 | max_dispatch = 1; | |
b4878f24 | 2320 | |
2f5cb738 JA |
2321 | /* |
2322 | * Does this cfqq already have too much IO in flight? | |
2323 | */ | |
2324 | if (cfqq->dispatched >= max_dispatch) { | |
2325 | /* | |
2326 | * idle queue must always only have a single IO in flight | |
2327 | */ | |
3ed9a296 | 2328 | if (cfq_class_idle(cfqq)) |
0b182d61 | 2329 | return false; |
3ed9a296 | 2330 | |
2f5cb738 JA |
2331 | /* |
2332 | * We have other queues, don't allow more IO from this one | |
2333 | */ | |
abc3c744 | 2334 | if (cfqd->busy_queues > 1 && cfq_slice_used_soon(cfqd, cfqq)) |
0b182d61 | 2335 | return false; |
9ede209e | 2336 | |
365722bb | 2337 | /* |
474b18cc | 2338 | * Sole queue user, no limit |
365722bb | 2339 | */ |
abc3c744 SL |
2340 | if (cfqd->busy_queues == 1) |
2341 | max_dispatch = -1; | |
2342 | else | |
2343 | /* | |
2344 | * Normally we start throttling cfqq when cfq_quantum/2 | |
2345 | * requests have been dispatched. But we can drive | |
2346 | * deeper queue depths at the beginning of slice | |
2347 | * subjected to upper limit of cfq_quantum. | |
2348 | * */ | |
2349 | max_dispatch = cfqd->cfq_quantum; | |
8e296755 JA |
2350 | } |
2351 | ||
2352 | /* | |
2353 | * Async queues must wait a bit before being allowed dispatch. | |
2354 | * We also ramp up the dispatch depth gradually for async IO, | |
2355 | * based on the last sync IO we serviced | |
2356 | */ | |
963b72fc | 2357 | if (!cfq_cfqq_sync(cfqq) && cfqd->cfq_latency) { |
573412b2 | 2358 | unsigned long last_sync = jiffies - cfqd->last_delayed_sync; |
8e296755 | 2359 | unsigned int depth; |
365722bb | 2360 | |
61f0c1dc | 2361 | depth = last_sync / cfqd->cfq_slice[1]; |
e00c54c3 JA |
2362 | if (!depth && !cfqq->dispatched) |
2363 | depth = 1; | |
8e296755 JA |
2364 | if (depth < max_dispatch) |
2365 | max_dispatch = depth; | |
2f5cb738 | 2366 | } |
3ed9a296 | 2367 | |
0b182d61 JA |
2368 | /* |
2369 | * If we're below the current max, allow a dispatch | |
2370 | */ | |
2371 | return cfqq->dispatched < max_dispatch; | |
2372 | } | |
2373 | ||
2374 | /* | |
2375 | * Dispatch a request from cfqq, moving them to the request queue | |
2376 | * dispatch list. | |
2377 | */ | |
2378 | static bool cfq_dispatch_request(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
2379 | { | |
2380 | struct request *rq; | |
2381 | ||
2382 | BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list)); | |
2383 | ||
2384 | if (!cfq_may_dispatch(cfqd, cfqq)) | |
2385 | return false; | |
2386 | ||
2387 | /* | |
2388 | * follow expired path, else get first next available | |
2389 | */ | |
2390 | rq = cfq_check_fifo(cfqq); | |
2391 | if (!rq) | |
2392 | rq = cfqq->next_rq; | |
2393 | ||
2394 | /* | |
2395 | * insert request into driver dispatch list | |
2396 | */ | |
2397 | cfq_dispatch_insert(cfqd->queue, rq); | |
2398 | ||
2399 | if (!cfqd->active_cic) { | |
2400 | struct cfq_io_context *cic = RQ_CIC(rq); | |
2401 | ||
2402 | atomic_long_inc(&cic->ioc->refcount); | |
2403 | cfqd->active_cic = cic; | |
2404 | } | |
2405 | ||
2406 | return true; | |
2407 | } | |
2408 | ||
2409 | /* | |
2410 | * Find the cfqq that we need to service and move a request from that to the | |
2411 | * dispatch list | |
2412 | */ | |
2413 | static int cfq_dispatch_requests(struct request_queue *q, int force) | |
2414 | { | |
2415 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
2416 | struct cfq_queue *cfqq; | |
2417 | ||
2418 | if (!cfqd->busy_queues) | |
2419 | return 0; | |
2420 | ||
2421 | if (unlikely(force)) | |
2422 | return cfq_forced_dispatch(cfqd); | |
2423 | ||
2424 | cfqq = cfq_select_queue(cfqd); | |
2425 | if (!cfqq) | |
8e296755 JA |
2426 | return 0; |
2427 | ||
2f5cb738 | 2428 | /* |
0b182d61 | 2429 | * Dispatch a request from this cfqq, if it is allowed |
2f5cb738 | 2430 | */ |
0b182d61 JA |
2431 | if (!cfq_dispatch_request(cfqd, cfqq)) |
2432 | return 0; | |
2433 | ||
2f5cb738 | 2434 | cfqq->slice_dispatch++; |
b029195d | 2435 | cfq_clear_cfqq_must_dispatch(cfqq); |
22e2c507 | 2436 | |
2f5cb738 JA |
2437 | /* |
2438 | * expire an async queue immediately if it has used up its slice. idle | |
2439 | * queue always expire after 1 dispatch round. | |
2440 | */ | |
2441 | if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) && | |
2442 | cfqq->slice_dispatch >= cfq_prio_to_maxrq(cfqd, cfqq)) || | |
2443 | cfq_class_idle(cfqq))) { | |
2444 | cfqq->slice_end = jiffies + 1; | |
e5ff082e | 2445 | cfq_slice_expired(cfqd, 0); |
1da177e4 LT |
2446 | } |
2447 | ||
b217a903 | 2448 | cfq_log_cfqq(cfqd, cfqq, "dispatched a request"); |
2f5cb738 | 2449 | return 1; |
1da177e4 LT |
2450 | } |
2451 | ||
1da177e4 | 2452 | /* |
5e705374 JA |
2453 | * task holds one reference to the queue, dropped when task exits. each rq |
2454 | * in-flight on this queue also holds a reference, dropped when rq is freed. | |
1da177e4 | 2455 | * |
b1c35769 | 2456 | * Each cfq queue took a reference on the parent group. Drop it now. |
1da177e4 LT |
2457 | * queue lock must be held here. |
2458 | */ | |
2459 | static void cfq_put_queue(struct cfq_queue *cfqq) | |
2460 | { | |
22e2c507 | 2461 | struct cfq_data *cfqd = cfqq->cfqd; |
878eaddd | 2462 | struct cfq_group *cfqg, *orig_cfqg; |
22e2c507 JA |
2463 | |
2464 | BUG_ON(atomic_read(&cfqq->ref) <= 0); | |
1da177e4 LT |
2465 | |
2466 | if (!atomic_dec_and_test(&cfqq->ref)) | |
2467 | return; | |
2468 | ||
7b679138 | 2469 | cfq_log_cfqq(cfqd, cfqq, "put_queue"); |
1da177e4 | 2470 | BUG_ON(rb_first(&cfqq->sort_list)); |
22e2c507 | 2471 | BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]); |
b1c35769 | 2472 | cfqg = cfqq->cfqg; |
878eaddd | 2473 | orig_cfqg = cfqq->orig_cfqg; |
1da177e4 | 2474 | |
28f95cbc | 2475 | if (unlikely(cfqd->active_queue == cfqq)) { |
e5ff082e | 2476 | __cfq_slice_expired(cfqd, cfqq, 0); |
23e018a1 | 2477 | cfq_schedule_dispatch(cfqd); |
28f95cbc | 2478 | } |
22e2c507 | 2479 | |
f04a6424 | 2480 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
1da177e4 | 2481 | kmem_cache_free(cfq_pool, cfqq); |
b1c35769 | 2482 | cfq_put_cfqg(cfqg); |
878eaddd VG |
2483 | if (orig_cfqg) |
2484 | cfq_put_cfqg(orig_cfqg); | |
1da177e4 LT |
2485 | } |
2486 | ||
d6de8be7 JA |
2487 | /* |
2488 | * Must always be called with the rcu_read_lock() held | |
2489 | */ | |
07416d29 JA |
2490 | static void |
2491 | __call_for_each_cic(struct io_context *ioc, | |
2492 | void (*func)(struct io_context *, struct cfq_io_context *)) | |
2493 | { | |
2494 | struct cfq_io_context *cic; | |
2495 | struct hlist_node *n; | |
2496 | ||
2497 | hlist_for_each_entry_rcu(cic, n, &ioc->cic_list, cic_list) | |
2498 | func(ioc, cic); | |
2499 | } | |
2500 | ||
4ac845a2 | 2501 | /* |
34e6bbf2 | 2502 | * Call func for each cic attached to this ioc. |
4ac845a2 | 2503 | */ |
34e6bbf2 | 2504 | static void |
4ac845a2 JA |
2505 | call_for_each_cic(struct io_context *ioc, |
2506 | void (*func)(struct io_context *, struct cfq_io_context *)) | |
1da177e4 | 2507 | { |
4ac845a2 | 2508 | rcu_read_lock(); |
07416d29 | 2509 | __call_for_each_cic(ioc, func); |
4ac845a2 | 2510 | rcu_read_unlock(); |
34e6bbf2 FC |
2511 | } |
2512 | ||
2513 | static void cfq_cic_free_rcu(struct rcu_head *head) | |
2514 | { | |
2515 | struct cfq_io_context *cic; | |
2516 | ||
2517 | cic = container_of(head, struct cfq_io_context, rcu_head); | |
2518 | ||
2519 | kmem_cache_free(cfq_ioc_pool, cic); | |
245b2e70 | 2520 | elv_ioc_count_dec(cfq_ioc_count); |
34e6bbf2 | 2521 | |
9a11b4ed JA |
2522 | if (ioc_gone) { |
2523 | /* | |
2524 | * CFQ scheduler is exiting, grab exit lock and check | |
2525 | * the pending io context count. If it hits zero, | |
2526 | * complete ioc_gone and set it back to NULL | |
2527 | */ | |
2528 | spin_lock(&ioc_gone_lock); | |
245b2e70 | 2529 | if (ioc_gone && !elv_ioc_count_read(cfq_ioc_count)) { |
9a11b4ed JA |
2530 | complete(ioc_gone); |
2531 | ioc_gone = NULL; | |
2532 | } | |
2533 | spin_unlock(&ioc_gone_lock); | |
2534 | } | |
34e6bbf2 | 2535 | } |
4ac845a2 | 2536 | |
34e6bbf2 FC |
2537 | static void cfq_cic_free(struct cfq_io_context *cic) |
2538 | { | |
2539 | call_rcu(&cic->rcu_head, cfq_cic_free_rcu); | |
4ac845a2 JA |
2540 | } |
2541 | ||
2542 | static void cic_free_func(struct io_context *ioc, struct cfq_io_context *cic) | |
2543 | { | |
2544 | unsigned long flags; | |
bca4b914 | 2545 | unsigned long dead_key = (unsigned long) cic->key; |
4ac845a2 | 2546 | |
bca4b914 | 2547 | BUG_ON(!(dead_key & CIC_DEAD_KEY)); |
4ac845a2 JA |
2548 | |
2549 | spin_lock_irqsave(&ioc->lock, flags); | |
80b15c73 | 2550 | radix_tree_delete(&ioc->radix_root, dead_key >> CIC_DEAD_INDEX_SHIFT); |
ffc4e759 | 2551 | hlist_del_rcu(&cic->cic_list); |
4ac845a2 JA |
2552 | spin_unlock_irqrestore(&ioc->lock, flags); |
2553 | ||
34e6bbf2 | 2554 | cfq_cic_free(cic); |
4ac845a2 JA |
2555 | } |
2556 | ||
d6de8be7 JA |
2557 | /* |
2558 | * Must be called with rcu_read_lock() held or preemption otherwise disabled. | |
2559 | * Only two callers of this - ->dtor() which is called with the rcu_read_lock(), | |
2560 | * and ->trim() which is called with the task lock held | |
2561 | */ | |
4ac845a2 JA |
2562 | static void cfq_free_io_context(struct io_context *ioc) |
2563 | { | |
4ac845a2 | 2564 | /* |
34e6bbf2 FC |
2565 | * ioc->refcount is zero here, or we are called from elv_unregister(), |
2566 | * so no more cic's are allowed to be linked into this ioc. So it | |
2567 | * should be ok to iterate over the known list, we will see all cic's | |
2568 | * since no new ones are added. | |
4ac845a2 | 2569 | */ |
07416d29 | 2570 | __call_for_each_cic(ioc, cic_free_func); |
1da177e4 LT |
2571 | } |
2572 | ||
d02a2c07 | 2573 | static void cfq_put_cooperator(struct cfq_queue *cfqq) |
1da177e4 | 2574 | { |
df5fe3e8 JM |
2575 | struct cfq_queue *__cfqq, *next; |
2576 | ||
df5fe3e8 JM |
2577 | /* |
2578 | * If this queue was scheduled to merge with another queue, be | |
2579 | * sure to drop the reference taken on that queue (and others in | |
2580 | * the merge chain). See cfq_setup_merge and cfq_merge_cfqqs. | |
2581 | */ | |
2582 | __cfqq = cfqq->new_cfqq; | |
2583 | while (__cfqq) { | |
2584 | if (__cfqq == cfqq) { | |
2585 | WARN(1, "cfqq->new_cfqq loop detected\n"); | |
2586 | break; | |
2587 | } | |
2588 | next = __cfqq->new_cfqq; | |
2589 | cfq_put_queue(__cfqq); | |
2590 | __cfqq = next; | |
2591 | } | |
d02a2c07 SL |
2592 | } |
2593 | ||
2594 | static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
2595 | { | |
2596 | if (unlikely(cfqq == cfqd->active_queue)) { | |
2597 | __cfq_slice_expired(cfqd, cfqq, 0); | |
2598 | cfq_schedule_dispatch(cfqd); | |
2599 | } | |
2600 | ||
2601 | cfq_put_cooperator(cfqq); | |
df5fe3e8 | 2602 | |
89850f7e JA |
2603 | cfq_put_queue(cfqq); |
2604 | } | |
22e2c507 | 2605 | |
89850f7e JA |
2606 | static void __cfq_exit_single_io_context(struct cfq_data *cfqd, |
2607 | struct cfq_io_context *cic) | |
2608 | { | |
4faa3c81 FC |
2609 | struct io_context *ioc = cic->ioc; |
2610 | ||
fc46379d | 2611 | list_del_init(&cic->queue_list); |
4ac845a2 JA |
2612 | |
2613 | /* | |
bca4b914 | 2614 | * Make sure dead mark is seen for dead queues |
4ac845a2 | 2615 | */ |
fc46379d | 2616 | smp_wmb(); |
bca4b914 | 2617 | cic->key = cfqd_dead_key(cfqd); |
fc46379d | 2618 | |
4faa3c81 FC |
2619 | if (ioc->ioc_data == cic) |
2620 | rcu_assign_pointer(ioc->ioc_data, NULL); | |
2621 | ||
ff6657c6 JA |
2622 | if (cic->cfqq[BLK_RW_ASYNC]) { |
2623 | cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_ASYNC]); | |
2624 | cic->cfqq[BLK_RW_ASYNC] = NULL; | |
12a05732 AV |
2625 | } |
2626 | ||
ff6657c6 JA |
2627 | if (cic->cfqq[BLK_RW_SYNC]) { |
2628 | cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_SYNC]); | |
2629 | cic->cfqq[BLK_RW_SYNC] = NULL; | |
12a05732 | 2630 | } |
89850f7e JA |
2631 | } |
2632 | ||
4ac845a2 JA |
2633 | static void cfq_exit_single_io_context(struct io_context *ioc, |
2634 | struct cfq_io_context *cic) | |
89850f7e | 2635 | { |
bca4b914 | 2636 | struct cfq_data *cfqd = cic_to_cfqd(cic); |
89850f7e | 2637 | |
89850f7e | 2638 | if (cfqd) { |
165125e1 | 2639 | struct request_queue *q = cfqd->queue; |
4ac845a2 | 2640 | unsigned long flags; |
89850f7e | 2641 | |
4ac845a2 | 2642 | spin_lock_irqsave(q->queue_lock, flags); |
62c1fe9d JA |
2643 | |
2644 | /* | |
2645 | * Ensure we get a fresh copy of the ->key to prevent | |
2646 | * race between exiting task and queue | |
2647 | */ | |
2648 | smp_read_barrier_depends(); | |
bca4b914 | 2649 | if (cic->key == cfqd) |
62c1fe9d JA |
2650 | __cfq_exit_single_io_context(cfqd, cic); |
2651 | ||
4ac845a2 | 2652 | spin_unlock_irqrestore(q->queue_lock, flags); |
89850f7e | 2653 | } |
1da177e4 LT |
2654 | } |
2655 | ||
498d3aa2 JA |
2656 | /* |
2657 | * The process that ioc belongs to has exited, we need to clean up | |
2658 | * and put the internal structures we have that belongs to that process. | |
2659 | */ | |
e2d74ac0 | 2660 | static void cfq_exit_io_context(struct io_context *ioc) |
1da177e4 | 2661 | { |
4ac845a2 | 2662 | call_for_each_cic(ioc, cfq_exit_single_io_context); |
1da177e4 LT |
2663 | } |
2664 | ||
22e2c507 | 2665 | static struct cfq_io_context * |
8267e268 | 2666 | cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
1da177e4 | 2667 | { |
b5deef90 | 2668 | struct cfq_io_context *cic; |
1da177e4 | 2669 | |
94f6030c CL |
2670 | cic = kmem_cache_alloc_node(cfq_ioc_pool, gfp_mask | __GFP_ZERO, |
2671 | cfqd->queue->node); | |
1da177e4 | 2672 | if (cic) { |
22e2c507 | 2673 | cic->last_end_request = jiffies; |
553698f9 | 2674 | INIT_LIST_HEAD(&cic->queue_list); |
ffc4e759 | 2675 | INIT_HLIST_NODE(&cic->cic_list); |
22e2c507 JA |
2676 | cic->dtor = cfq_free_io_context; |
2677 | cic->exit = cfq_exit_io_context; | |
245b2e70 | 2678 | elv_ioc_count_inc(cfq_ioc_count); |
1da177e4 LT |
2679 | } |
2680 | ||
2681 | return cic; | |
2682 | } | |
2683 | ||
fd0928df | 2684 | static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc) |
22e2c507 JA |
2685 | { |
2686 | struct task_struct *tsk = current; | |
2687 | int ioprio_class; | |
2688 | ||
3b18152c | 2689 | if (!cfq_cfqq_prio_changed(cfqq)) |
22e2c507 JA |
2690 | return; |
2691 | ||
fd0928df | 2692 | ioprio_class = IOPRIO_PRIO_CLASS(ioc->ioprio); |
22e2c507 | 2693 | switch (ioprio_class) { |
fe094d98 JA |
2694 | default: |
2695 | printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class); | |
2696 | case IOPRIO_CLASS_NONE: | |
2697 | /* | |
6d63c275 | 2698 | * no prio set, inherit CPU scheduling settings |
fe094d98 JA |
2699 | */ |
2700 | cfqq->ioprio = task_nice_ioprio(tsk); | |
6d63c275 | 2701 | cfqq->ioprio_class = task_nice_ioclass(tsk); |
fe094d98 JA |
2702 | break; |
2703 | case IOPRIO_CLASS_RT: | |
2704 | cfqq->ioprio = task_ioprio(ioc); | |
2705 | cfqq->ioprio_class = IOPRIO_CLASS_RT; | |
2706 | break; | |
2707 | case IOPRIO_CLASS_BE: | |
2708 | cfqq->ioprio = task_ioprio(ioc); | |
2709 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
2710 | break; | |
2711 | case IOPRIO_CLASS_IDLE: | |
2712 | cfqq->ioprio_class = IOPRIO_CLASS_IDLE; | |
2713 | cfqq->ioprio = 7; | |
2714 | cfq_clear_cfqq_idle_window(cfqq); | |
2715 | break; | |
22e2c507 JA |
2716 | } |
2717 | ||
2718 | /* | |
2719 | * keep track of original prio settings in case we have to temporarily | |
2720 | * elevate the priority of this queue | |
2721 | */ | |
2722 | cfqq->org_ioprio = cfqq->ioprio; | |
2723 | cfqq->org_ioprio_class = cfqq->ioprio_class; | |
3b18152c | 2724 | cfq_clear_cfqq_prio_changed(cfqq); |
22e2c507 JA |
2725 | } |
2726 | ||
febffd61 | 2727 | static void changed_ioprio(struct io_context *ioc, struct cfq_io_context *cic) |
22e2c507 | 2728 | { |
bca4b914 | 2729 | struct cfq_data *cfqd = cic_to_cfqd(cic); |
478a82b0 | 2730 | struct cfq_queue *cfqq; |
c1b707d2 | 2731 | unsigned long flags; |
35e6077c | 2732 | |
caaa5f9f JA |
2733 | if (unlikely(!cfqd)) |
2734 | return; | |
2735 | ||
c1b707d2 | 2736 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); |
caaa5f9f | 2737 | |
ff6657c6 | 2738 | cfqq = cic->cfqq[BLK_RW_ASYNC]; |
caaa5f9f JA |
2739 | if (cfqq) { |
2740 | struct cfq_queue *new_cfqq; | |
ff6657c6 JA |
2741 | new_cfqq = cfq_get_queue(cfqd, BLK_RW_ASYNC, cic->ioc, |
2742 | GFP_ATOMIC); | |
caaa5f9f | 2743 | if (new_cfqq) { |
ff6657c6 | 2744 | cic->cfqq[BLK_RW_ASYNC] = new_cfqq; |
caaa5f9f JA |
2745 | cfq_put_queue(cfqq); |
2746 | } | |
22e2c507 | 2747 | } |
caaa5f9f | 2748 | |
ff6657c6 | 2749 | cfqq = cic->cfqq[BLK_RW_SYNC]; |
caaa5f9f JA |
2750 | if (cfqq) |
2751 | cfq_mark_cfqq_prio_changed(cfqq); | |
2752 | ||
c1b707d2 | 2753 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); |
22e2c507 JA |
2754 | } |
2755 | ||
fc46379d | 2756 | static void cfq_ioc_set_ioprio(struct io_context *ioc) |
22e2c507 | 2757 | { |
4ac845a2 | 2758 | call_for_each_cic(ioc, changed_ioprio); |
fc46379d | 2759 | ioc->ioprio_changed = 0; |
22e2c507 JA |
2760 | } |
2761 | ||
d5036d77 | 2762 | static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
a6151c3a | 2763 | pid_t pid, bool is_sync) |
d5036d77 JA |
2764 | { |
2765 | RB_CLEAR_NODE(&cfqq->rb_node); | |
2766 | RB_CLEAR_NODE(&cfqq->p_node); | |
2767 | INIT_LIST_HEAD(&cfqq->fifo); | |
2768 | ||
2769 | atomic_set(&cfqq->ref, 0); | |
2770 | cfqq->cfqd = cfqd; | |
2771 | ||
2772 | cfq_mark_cfqq_prio_changed(cfqq); | |
2773 | ||
2774 | if (is_sync) { | |
2775 | if (!cfq_class_idle(cfqq)) | |
2776 | cfq_mark_cfqq_idle_window(cfqq); | |
2777 | cfq_mark_cfqq_sync(cfqq); | |
2778 | } | |
2779 | cfqq->pid = pid; | |
2780 | } | |
2781 | ||
24610333 VG |
2782 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
2783 | static void changed_cgroup(struct io_context *ioc, struct cfq_io_context *cic) | |
2784 | { | |
2785 | struct cfq_queue *sync_cfqq = cic_to_cfqq(cic, 1); | |
bca4b914 | 2786 | struct cfq_data *cfqd = cic_to_cfqd(cic); |
24610333 VG |
2787 | unsigned long flags; |
2788 | struct request_queue *q; | |
2789 | ||
2790 | if (unlikely(!cfqd)) | |
2791 | return; | |
2792 | ||
2793 | q = cfqd->queue; | |
2794 | ||
2795 | spin_lock_irqsave(q->queue_lock, flags); | |
2796 | ||
2797 | if (sync_cfqq) { | |
2798 | /* | |
2799 | * Drop reference to sync queue. A new sync queue will be | |
2800 | * assigned in new group upon arrival of a fresh request. | |
2801 | */ | |
2802 | cfq_log_cfqq(cfqd, sync_cfqq, "changed cgroup"); | |
2803 | cic_set_cfqq(cic, NULL, 1); | |
2804 | cfq_put_queue(sync_cfqq); | |
2805 | } | |
2806 | ||
2807 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2808 | } | |
2809 | ||
2810 | static void cfq_ioc_set_cgroup(struct io_context *ioc) | |
2811 | { | |
2812 | call_for_each_cic(ioc, changed_cgroup); | |
2813 | ioc->cgroup_changed = 0; | |
2814 | } | |
2815 | #endif /* CONFIG_CFQ_GROUP_IOSCHED */ | |
2816 | ||
22e2c507 | 2817 | static struct cfq_queue * |
a6151c3a | 2818 | cfq_find_alloc_queue(struct cfq_data *cfqd, bool is_sync, |
fd0928df | 2819 | struct io_context *ioc, gfp_t gfp_mask) |
22e2c507 | 2820 | { |
22e2c507 | 2821 | struct cfq_queue *cfqq, *new_cfqq = NULL; |
91fac317 | 2822 | struct cfq_io_context *cic; |
cdb16e8f | 2823 | struct cfq_group *cfqg; |
22e2c507 JA |
2824 | |
2825 | retry: | |
cdb16e8f | 2826 | cfqg = cfq_get_cfqg(cfqd, 1); |
4ac845a2 | 2827 | cic = cfq_cic_lookup(cfqd, ioc); |
91fac317 VT |
2828 | /* cic always exists here */ |
2829 | cfqq = cic_to_cfqq(cic, is_sync); | |
22e2c507 | 2830 | |
6118b70b JA |
2831 | /* |
2832 | * Always try a new alloc if we fell back to the OOM cfqq | |
2833 | * originally, since it should just be a temporary situation. | |
2834 | */ | |
2835 | if (!cfqq || cfqq == &cfqd->oom_cfqq) { | |
2836 | cfqq = NULL; | |
22e2c507 JA |
2837 | if (new_cfqq) { |
2838 | cfqq = new_cfqq; | |
2839 | new_cfqq = NULL; | |
2840 | } else if (gfp_mask & __GFP_WAIT) { | |
2841 | spin_unlock_irq(cfqd->queue->queue_lock); | |
94f6030c | 2842 | new_cfqq = kmem_cache_alloc_node(cfq_pool, |
6118b70b | 2843 | gfp_mask | __GFP_ZERO, |
94f6030c | 2844 | cfqd->queue->node); |
22e2c507 | 2845 | spin_lock_irq(cfqd->queue->queue_lock); |
6118b70b JA |
2846 | if (new_cfqq) |
2847 | goto retry; | |
22e2c507 | 2848 | } else { |
94f6030c CL |
2849 | cfqq = kmem_cache_alloc_node(cfq_pool, |
2850 | gfp_mask | __GFP_ZERO, | |
2851 | cfqd->queue->node); | |
22e2c507 JA |
2852 | } |
2853 | ||
6118b70b JA |
2854 | if (cfqq) { |
2855 | cfq_init_cfqq(cfqd, cfqq, current->pid, is_sync); | |
2856 | cfq_init_prio_data(cfqq, ioc); | |
cdb16e8f | 2857 | cfq_link_cfqq_cfqg(cfqq, cfqg); |
6118b70b JA |
2858 | cfq_log_cfqq(cfqd, cfqq, "alloced"); |
2859 | } else | |
2860 | cfqq = &cfqd->oom_cfqq; | |
22e2c507 JA |
2861 | } |
2862 | ||
2863 | if (new_cfqq) | |
2864 | kmem_cache_free(cfq_pool, new_cfqq); | |
2865 | ||
22e2c507 JA |
2866 | return cfqq; |
2867 | } | |
2868 | ||
c2dea2d1 VT |
2869 | static struct cfq_queue ** |
2870 | cfq_async_queue_prio(struct cfq_data *cfqd, int ioprio_class, int ioprio) | |
2871 | { | |
fe094d98 | 2872 | switch (ioprio_class) { |
c2dea2d1 VT |
2873 | case IOPRIO_CLASS_RT: |
2874 | return &cfqd->async_cfqq[0][ioprio]; | |
2875 | case IOPRIO_CLASS_BE: | |
2876 | return &cfqd->async_cfqq[1][ioprio]; | |
2877 | case IOPRIO_CLASS_IDLE: | |
2878 | return &cfqd->async_idle_cfqq; | |
2879 | default: | |
2880 | BUG(); | |
2881 | } | |
2882 | } | |
2883 | ||
15c31be4 | 2884 | static struct cfq_queue * |
a6151c3a | 2885 | cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct io_context *ioc, |
15c31be4 JA |
2886 | gfp_t gfp_mask) |
2887 | { | |
fd0928df JA |
2888 | const int ioprio = task_ioprio(ioc); |
2889 | const int ioprio_class = task_ioprio_class(ioc); | |
c2dea2d1 | 2890 | struct cfq_queue **async_cfqq = NULL; |
15c31be4 JA |
2891 | struct cfq_queue *cfqq = NULL; |
2892 | ||
c2dea2d1 VT |
2893 | if (!is_sync) { |
2894 | async_cfqq = cfq_async_queue_prio(cfqd, ioprio_class, ioprio); | |
2895 | cfqq = *async_cfqq; | |
2896 | } | |
2897 | ||
6118b70b | 2898 | if (!cfqq) |
fd0928df | 2899 | cfqq = cfq_find_alloc_queue(cfqd, is_sync, ioc, gfp_mask); |
15c31be4 JA |
2900 | |
2901 | /* | |
2902 | * pin the queue now that it's allocated, scheduler exit will prune it | |
2903 | */ | |
c2dea2d1 | 2904 | if (!is_sync && !(*async_cfqq)) { |
15c31be4 | 2905 | atomic_inc(&cfqq->ref); |
c2dea2d1 | 2906 | *async_cfqq = cfqq; |
15c31be4 JA |
2907 | } |
2908 | ||
2909 | atomic_inc(&cfqq->ref); | |
2910 | return cfqq; | |
2911 | } | |
2912 | ||
498d3aa2 JA |
2913 | /* |
2914 | * We drop cfq io contexts lazily, so we may find a dead one. | |
2915 | */ | |
dbecf3ab | 2916 | static void |
4ac845a2 JA |
2917 | cfq_drop_dead_cic(struct cfq_data *cfqd, struct io_context *ioc, |
2918 | struct cfq_io_context *cic) | |
dbecf3ab | 2919 | { |
4ac845a2 JA |
2920 | unsigned long flags; |
2921 | ||
fc46379d | 2922 | WARN_ON(!list_empty(&cic->queue_list)); |
bca4b914 | 2923 | BUG_ON(cic->key != cfqd_dead_key(cfqd)); |
597bc485 | 2924 | |
4ac845a2 JA |
2925 | spin_lock_irqsave(&ioc->lock, flags); |
2926 | ||
4faa3c81 | 2927 | BUG_ON(ioc->ioc_data == cic); |
597bc485 | 2928 | |
80b15c73 | 2929 | radix_tree_delete(&ioc->radix_root, cfqd->cic_index); |
ffc4e759 | 2930 | hlist_del_rcu(&cic->cic_list); |
4ac845a2 JA |
2931 | spin_unlock_irqrestore(&ioc->lock, flags); |
2932 | ||
2933 | cfq_cic_free(cic); | |
dbecf3ab OH |
2934 | } |
2935 | ||
e2d74ac0 | 2936 | static struct cfq_io_context * |
4ac845a2 | 2937 | cfq_cic_lookup(struct cfq_data *cfqd, struct io_context *ioc) |
e2d74ac0 | 2938 | { |
e2d74ac0 | 2939 | struct cfq_io_context *cic; |
d6de8be7 | 2940 | unsigned long flags; |
e2d74ac0 | 2941 | |
91fac317 VT |
2942 | if (unlikely(!ioc)) |
2943 | return NULL; | |
2944 | ||
d6de8be7 JA |
2945 | rcu_read_lock(); |
2946 | ||
597bc485 JA |
2947 | /* |
2948 | * we maintain a last-hit cache, to avoid browsing over the tree | |
2949 | */ | |
4ac845a2 | 2950 | cic = rcu_dereference(ioc->ioc_data); |
d6de8be7 JA |
2951 | if (cic && cic->key == cfqd) { |
2952 | rcu_read_unlock(); | |
597bc485 | 2953 | return cic; |
d6de8be7 | 2954 | } |
597bc485 | 2955 | |
4ac845a2 | 2956 | do { |
80b15c73 | 2957 | cic = radix_tree_lookup(&ioc->radix_root, cfqd->cic_index); |
4ac845a2 JA |
2958 | rcu_read_unlock(); |
2959 | if (!cic) | |
2960 | break; | |
bca4b914 | 2961 | if (unlikely(cic->key != cfqd)) { |
4ac845a2 | 2962 | cfq_drop_dead_cic(cfqd, ioc, cic); |
d6de8be7 | 2963 | rcu_read_lock(); |
4ac845a2 | 2964 | continue; |
dbecf3ab | 2965 | } |
e2d74ac0 | 2966 | |
d6de8be7 | 2967 | spin_lock_irqsave(&ioc->lock, flags); |
4ac845a2 | 2968 | rcu_assign_pointer(ioc->ioc_data, cic); |
d6de8be7 | 2969 | spin_unlock_irqrestore(&ioc->lock, flags); |
4ac845a2 JA |
2970 | break; |
2971 | } while (1); | |
e2d74ac0 | 2972 | |
4ac845a2 | 2973 | return cic; |
e2d74ac0 JA |
2974 | } |
2975 | ||
4ac845a2 JA |
2976 | /* |
2977 | * Add cic into ioc, using cfqd as the search key. This enables us to lookup | |
2978 | * the process specific cfq io context when entered from the block layer. | |
2979 | * Also adds the cic to a per-cfqd list, used when this queue is removed. | |
2980 | */ | |
febffd61 JA |
2981 | static int cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc, |
2982 | struct cfq_io_context *cic, gfp_t gfp_mask) | |
e2d74ac0 | 2983 | { |
0261d688 | 2984 | unsigned long flags; |
4ac845a2 | 2985 | int ret; |
e2d74ac0 | 2986 | |
4ac845a2 JA |
2987 | ret = radix_tree_preload(gfp_mask); |
2988 | if (!ret) { | |
2989 | cic->ioc = ioc; | |
2990 | cic->key = cfqd; | |
e2d74ac0 | 2991 | |
4ac845a2 JA |
2992 | spin_lock_irqsave(&ioc->lock, flags); |
2993 | ret = radix_tree_insert(&ioc->radix_root, | |
80b15c73 | 2994 | cfqd->cic_index, cic); |
ffc4e759 JA |
2995 | if (!ret) |
2996 | hlist_add_head_rcu(&cic->cic_list, &ioc->cic_list); | |
4ac845a2 | 2997 | spin_unlock_irqrestore(&ioc->lock, flags); |
e2d74ac0 | 2998 | |
4ac845a2 JA |
2999 | radix_tree_preload_end(); |
3000 | ||
3001 | if (!ret) { | |
3002 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
3003 | list_add(&cic->queue_list, &cfqd->cic_list); | |
3004 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
3005 | } | |
e2d74ac0 JA |
3006 | } |
3007 | ||
4ac845a2 JA |
3008 | if (ret) |
3009 | printk(KERN_ERR "cfq: cic link failed!\n"); | |
fc46379d | 3010 | |
4ac845a2 | 3011 | return ret; |
e2d74ac0 JA |
3012 | } |
3013 | ||
1da177e4 LT |
3014 | /* |
3015 | * Setup general io context and cfq io context. There can be several cfq | |
3016 | * io contexts per general io context, if this process is doing io to more | |
e2d74ac0 | 3017 | * than one device managed by cfq. |
1da177e4 LT |
3018 | */ |
3019 | static struct cfq_io_context * | |
e2d74ac0 | 3020 | cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
1da177e4 | 3021 | { |
22e2c507 | 3022 | struct io_context *ioc = NULL; |
1da177e4 | 3023 | struct cfq_io_context *cic; |
1da177e4 | 3024 | |
22e2c507 | 3025 | might_sleep_if(gfp_mask & __GFP_WAIT); |
1da177e4 | 3026 | |
b5deef90 | 3027 | ioc = get_io_context(gfp_mask, cfqd->queue->node); |
1da177e4 LT |
3028 | if (!ioc) |
3029 | return NULL; | |
3030 | ||
4ac845a2 | 3031 | cic = cfq_cic_lookup(cfqd, ioc); |
e2d74ac0 JA |
3032 | if (cic) |
3033 | goto out; | |
1da177e4 | 3034 | |
e2d74ac0 JA |
3035 | cic = cfq_alloc_io_context(cfqd, gfp_mask); |
3036 | if (cic == NULL) | |
3037 | goto err; | |
1da177e4 | 3038 | |
4ac845a2 JA |
3039 | if (cfq_cic_link(cfqd, ioc, cic, gfp_mask)) |
3040 | goto err_free; | |
3041 | ||
1da177e4 | 3042 | out: |
fc46379d JA |
3043 | smp_read_barrier_depends(); |
3044 | if (unlikely(ioc->ioprio_changed)) | |
3045 | cfq_ioc_set_ioprio(ioc); | |
3046 | ||
24610333 VG |
3047 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
3048 | if (unlikely(ioc->cgroup_changed)) | |
3049 | cfq_ioc_set_cgroup(ioc); | |
3050 | #endif | |
1da177e4 | 3051 | return cic; |
4ac845a2 JA |
3052 | err_free: |
3053 | cfq_cic_free(cic); | |
1da177e4 LT |
3054 | err: |
3055 | put_io_context(ioc); | |
3056 | return NULL; | |
3057 | } | |
3058 | ||
22e2c507 JA |
3059 | static void |
3060 | cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic) | |
1da177e4 | 3061 | { |
aaf1228d JA |
3062 | unsigned long elapsed = jiffies - cic->last_end_request; |
3063 | unsigned long ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle); | |
db3b5848 | 3064 | |
22e2c507 JA |
3065 | cic->ttime_samples = (7*cic->ttime_samples + 256) / 8; |
3066 | cic->ttime_total = (7*cic->ttime_total + 256*ttime) / 8; | |
3067 | cic->ttime_mean = (cic->ttime_total + 128) / cic->ttime_samples; | |
3068 | } | |
1da177e4 | 3069 | |
206dc69b | 3070 | static void |
b2c18e1e | 3071 | cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
6d048f53 | 3072 | struct request *rq) |
206dc69b | 3073 | { |
3dde36dd | 3074 | sector_t sdist = 0; |
41647e7a | 3075 | sector_t n_sec = blk_rq_sectors(rq); |
3dde36dd CZ |
3076 | if (cfqq->last_request_pos) { |
3077 | if (cfqq->last_request_pos < blk_rq_pos(rq)) | |
3078 | sdist = blk_rq_pos(rq) - cfqq->last_request_pos; | |
3079 | else | |
3080 | sdist = cfqq->last_request_pos - blk_rq_pos(rq); | |
3081 | } | |
206dc69b | 3082 | |
3dde36dd | 3083 | cfqq->seek_history <<= 1; |
41647e7a CZ |
3084 | if (blk_queue_nonrot(cfqd->queue)) |
3085 | cfqq->seek_history |= (n_sec < CFQQ_SECT_THR_NONROT); | |
3086 | else | |
3087 | cfqq->seek_history |= (sdist > CFQQ_SEEK_THR); | |
206dc69b | 3088 | } |
1da177e4 | 3089 | |
22e2c507 JA |
3090 | /* |
3091 | * Disable idle window if the process thinks too long or seeks so much that | |
3092 | * it doesn't matter | |
3093 | */ | |
3094 | static void | |
3095 | cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
3096 | struct cfq_io_context *cic) | |
3097 | { | |
7b679138 | 3098 | int old_idle, enable_idle; |
1be92f2f | 3099 | |
0871714e JA |
3100 | /* |
3101 | * Don't idle for async or idle io prio class | |
3102 | */ | |
3103 | if (!cfq_cfqq_sync(cfqq) || cfq_class_idle(cfqq)) | |
1be92f2f JA |
3104 | return; |
3105 | ||
c265a7f4 | 3106 | enable_idle = old_idle = cfq_cfqq_idle_window(cfqq); |
1da177e4 | 3107 | |
76280aff CZ |
3108 | if (cfqq->queued[0] + cfqq->queued[1] >= 4) |
3109 | cfq_mark_cfqq_deep(cfqq); | |
3110 | ||
66dac98e | 3111 | if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle || |
3dde36dd | 3112 | (!cfq_cfqq_deep(cfqq) && CFQQ_SEEKY(cfqq))) |
22e2c507 JA |
3113 | enable_idle = 0; |
3114 | else if (sample_valid(cic->ttime_samples)) { | |
718eee05 | 3115 | if (cic->ttime_mean > cfqd->cfq_slice_idle) |
22e2c507 JA |
3116 | enable_idle = 0; |
3117 | else | |
3118 | enable_idle = 1; | |
1da177e4 LT |
3119 | } |
3120 | ||
7b679138 JA |
3121 | if (old_idle != enable_idle) { |
3122 | cfq_log_cfqq(cfqd, cfqq, "idle=%d", enable_idle); | |
3123 | if (enable_idle) | |
3124 | cfq_mark_cfqq_idle_window(cfqq); | |
3125 | else | |
3126 | cfq_clear_cfqq_idle_window(cfqq); | |
3127 | } | |
22e2c507 | 3128 | } |
1da177e4 | 3129 | |
22e2c507 JA |
3130 | /* |
3131 | * Check if new_cfqq should preempt the currently active queue. Return 0 for | |
3132 | * no or if we aren't sure, a 1 will cause a preempt. | |
3133 | */ | |
a6151c3a | 3134 | static bool |
22e2c507 | 3135 | cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, |
5e705374 | 3136 | struct request *rq) |
22e2c507 | 3137 | { |
6d048f53 | 3138 | struct cfq_queue *cfqq; |
22e2c507 | 3139 | |
6d048f53 JA |
3140 | cfqq = cfqd->active_queue; |
3141 | if (!cfqq) | |
a6151c3a | 3142 | return false; |
22e2c507 | 3143 | |
6d048f53 | 3144 | if (cfq_class_idle(new_cfqq)) |
a6151c3a | 3145 | return false; |
22e2c507 JA |
3146 | |
3147 | if (cfq_class_idle(cfqq)) | |
a6151c3a | 3148 | return true; |
1e3335de | 3149 | |
875feb63 DS |
3150 | /* |
3151 | * Don't allow a non-RT request to preempt an ongoing RT cfqq timeslice. | |
3152 | */ | |
3153 | if (cfq_class_rt(cfqq) && !cfq_class_rt(new_cfqq)) | |
3154 | return false; | |
3155 | ||
374f84ac JA |
3156 | /* |
3157 | * if the new request is sync, but the currently running queue is | |
3158 | * not, let the sync request have priority. | |
3159 | */ | |
5e705374 | 3160 | if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq)) |
a6151c3a | 3161 | return true; |
1e3335de | 3162 | |
8682e1f1 VG |
3163 | if (new_cfqq->cfqg != cfqq->cfqg) |
3164 | return false; | |
3165 | ||
3166 | if (cfq_slice_used(cfqq)) | |
3167 | return true; | |
3168 | ||
3169 | /* Allow preemption only if we are idling on sync-noidle tree */ | |
3170 | if (cfqd->serving_type == SYNC_NOIDLE_WORKLOAD && | |
3171 | cfqq_type(new_cfqq) == SYNC_NOIDLE_WORKLOAD && | |
3172 | new_cfqq->service_tree->count == 2 && | |
3173 | RB_EMPTY_ROOT(&cfqq->sort_list)) | |
3174 | return true; | |
3175 | ||
374f84ac JA |
3176 | /* |
3177 | * So both queues are sync. Let the new request get disk time if | |
3178 | * it's a metadata request and the current queue is doing regular IO. | |
3179 | */ | |
7b6d91da | 3180 | if ((rq->cmd_flags & REQ_META) && !cfqq->meta_pending) |
e6ec4fe2 | 3181 | return true; |
22e2c507 | 3182 | |
3a9a3f6c DS |
3183 | /* |
3184 | * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice. | |
3185 | */ | |
3186 | if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq)) | |
a6151c3a | 3187 | return true; |
3a9a3f6c | 3188 | |
1e3335de | 3189 | if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq)) |
a6151c3a | 3190 | return false; |
1e3335de JA |
3191 | |
3192 | /* | |
3193 | * if this request is as-good as one we would expect from the | |
3194 | * current cfqq, let it preempt | |
3195 | */ | |
e9ce335d | 3196 | if (cfq_rq_close(cfqd, cfqq, rq)) |
a6151c3a | 3197 | return true; |
1e3335de | 3198 | |
a6151c3a | 3199 | return false; |
22e2c507 JA |
3200 | } |
3201 | ||
3202 | /* | |
3203 | * cfqq preempts the active queue. if we allowed preempt with no slice left, | |
3204 | * let it have half of its nominal slice. | |
3205 | */ | |
3206 | static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
3207 | { | |
7b679138 | 3208 | cfq_log_cfqq(cfqd, cfqq, "preempt"); |
e5ff082e | 3209 | cfq_slice_expired(cfqd, 1); |
22e2c507 | 3210 | |
bf572256 JA |
3211 | /* |
3212 | * Put the new queue at the front of the of the current list, | |
3213 | * so we know that it will be selected next. | |
3214 | */ | |
3215 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); | |
edd75ffd JA |
3216 | |
3217 | cfq_service_tree_add(cfqd, cfqq, 1); | |
bf572256 | 3218 | |
44f7c160 JA |
3219 | cfqq->slice_end = 0; |
3220 | cfq_mark_cfqq_slice_new(cfqq); | |
22e2c507 JA |
3221 | } |
3222 | ||
22e2c507 | 3223 | /* |
5e705374 | 3224 | * Called when a new fs request (rq) is added (to cfqq). Check if there's |
22e2c507 JA |
3225 | * something we should do about it |
3226 | */ | |
3227 | static void | |
5e705374 JA |
3228 | cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
3229 | struct request *rq) | |
22e2c507 | 3230 | { |
5e705374 | 3231 | struct cfq_io_context *cic = RQ_CIC(rq); |
12e9fddd | 3232 | |
45333d5a | 3233 | cfqd->rq_queued++; |
7b6d91da | 3234 | if (rq->cmd_flags & REQ_META) |
374f84ac JA |
3235 | cfqq->meta_pending++; |
3236 | ||
9c2c38a1 | 3237 | cfq_update_io_thinktime(cfqd, cic); |
b2c18e1e | 3238 | cfq_update_io_seektime(cfqd, cfqq, rq); |
9c2c38a1 JA |
3239 | cfq_update_idle_window(cfqd, cfqq, cic); |
3240 | ||
b2c18e1e | 3241 | cfqq->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq); |
22e2c507 JA |
3242 | |
3243 | if (cfqq == cfqd->active_queue) { | |
3244 | /* | |
b029195d JA |
3245 | * Remember that we saw a request from this process, but |
3246 | * don't start queuing just yet. Otherwise we risk seeing lots | |
3247 | * of tiny requests, because we disrupt the normal plugging | |
d6ceb25e JA |
3248 | * and merging. If the request is already larger than a single |
3249 | * page, let it rip immediately. For that case we assume that | |
2d870722 JA |
3250 | * merging is already done. Ditto for a busy system that |
3251 | * has other work pending, don't risk delaying until the | |
3252 | * idle timer unplug to continue working. | |
22e2c507 | 3253 | */ |
d6ceb25e | 3254 | if (cfq_cfqq_wait_request(cfqq)) { |
2d870722 JA |
3255 | if (blk_rq_bytes(rq) > PAGE_CACHE_SIZE || |
3256 | cfqd->busy_queues > 1) { | |
812df48d | 3257 | cfq_del_timer(cfqd, cfqq); |
554554f6 | 3258 | cfq_clear_cfqq_wait_request(cfqq); |
bf791937 | 3259 | __blk_run_queue(cfqd->queue); |
a11cdaa7 | 3260 | } else { |
e98ef89b | 3261 | cfq_blkiocg_update_idle_time_stats( |
a11cdaa7 | 3262 | &cfqq->cfqg->blkg); |
bf791937 | 3263 | cfq_mark_cfqq_must_dispatch(cfqq); |
a11cdaa7 | 3264 | } |
d6ceb25e | 3265 | } |
5e705374 | 3266 | } else if (cfq_should_preempt(cfqd, cfqq, rq)) { |
22e2c507 JA |
3267 | /* |
3268 | * not the active queue - expire current slice if it is | |
3269 | * idle and has expired it's mean thinktime or this new queue | |
3a9a3f6c DS |
3270 | * has some old slice time left and is of higher priority or |
3271 | * this new queue is RT and the current one is BE | |
22e2c507 JA |
3272 | */ |
3273 | cfq_preempt_queue(cfqd, cfqq); | |
a7f55792 | 3274 | __blk_run_queue(cfqd->queue); |
22e2c507 | 3275 | } |
1da177e4 LT |
3276 | } |
3277 | ||
165125e1 | 3278 | static void cfq_insert_request(struct request_queue *q, struct request *rq) |
1da177e4 | 3279 | { |
b4878f24 | 3280 | struct cfq_data *cfqd = q->elevator->elevator_data; |
5e705374 | 3281 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 | 3282 | |
7b679138 | 3283 | cfq_log_cfqq(cfqd, cfqq, "insert_request"); |
fd0928df | 3284 | cfq_init_prio_data(cfqq, RQ_CIC(rq)->ioc); |
1da177e4 | 3285 | |
30996f40 | 3286 | rq_set_fifo_time(rq, jiffies + cfqd->cfq_fifo_expire[rq_is_sync(rq)]); |
22e2c507 | 3287 | list_add_tail(&rq->queuelist, &cfqq->fifo); |
aa6f6a3d | 3288 | cfq_add_rq_rb(rq); |
e98ef89b | 3289 | cfq_blkiocg_update_io_add_stats(&(RQ_CFQG(rq))->blkg, |
cdc1184c DS |
3290 | &cfqd->serving_group->blkg, rq_data_dir(rq), |
3291 | rq_is_sync(rq)); | |
5e705374 | 3292 | cfq_rq_enqueued(cfqd, cfqq, rq); |
1da177e4 LT |
3293 | } |
3294 | ||
45333d5a AC |
3295 | /* |
3296 | * Update hw_tag based on peak queue depth over 50 samples under | |
3297 | * sufficient load. | |
3298 | */ | |
3299 | static void cfq_update_hw_tag(struct cfq_data *cfqd) | |
3300 | { | |
1a1238a7 SL |
3301 | struct cfq_queue *cfqq = cfqd->active_queue; |
3302 | ||
53c583d2 CZ |
3303 | if (cfqd->rq_in_driver > cfqd->hw_tag_est_depth) |
3304 | cfqd->hw_tag_est_depth = cfqd->rq_in_driver; | |
e459dd08 CZ |
3305 | |
3306 | if (cfqd->hw_tag == 1) | |
3307 | return; | |
45333d5a AC |
3308 | |
3309 | if (cfqd->rq_queued <= CFQ_HW_QUEUE_MIN && | |
53c583d2 | 3310 | cfqd->rq_in_driver <= CFQ_HW_QUEUE_MIN) |
45333d5a AC |
3311 | return; |
3312 | ||
1a1238a7 SL |
3313 | /* |
3314 | * If active queue hasn't enough requests and can idle, cfq might not | |
3315 | * dispatch sufficient requests to hardware. Don't zero hw_tag in this | |
3316 | * case | |
3317 | */ | |
3318 | if (cfqq && cfq_cfqq_idle_window(cfqq) && | |
3319 | cfqq->dispatched + cfqq->queued[0] + cfqq->queued[1] < | |
53c583d2 | 3320 | CFQ_HW_QUEUE_MIN && cfqd->rq_in_driver < CFQ_HW_QUEUE_MIN) |
1a1238a7 SL |
3321 | return; |
3322 | ||
45333d5a AC |
3323 | if (cfqd->hw_tag_samples++ < 50) |
3324 | return; | |
3325 | ||
e459dd08 | 3326 | if (cfqd->hw_tag_est_depth >= CFQ_HW_QUEUE_MIN) |
45333d5a AC |
3327 | cfqd->hw_tag = 1; |
3328 | else | |
3329 | cfqd->hw_tag = 0; | |
45333d5a AC |
3330 | } |
3331 | ||
7667aa06 VG |
3332 | static bool cfq_should_wait_busy(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
3333 | { | |
3334 | struct cfq_io_context *cic = cfqd->active_cic; | |
3335 | ||
3336 | /* If there are other queues in the group, don't wait */ | |
3337 | if (cfqq->cfqg->nr_cfqq > 1) | |
3338 | return false; | |
3339 | ||
3340 | if (cfq_slice_used(cfqq)) | |
3341 | return true; | |
3342 | ||
3343 | /* if slice left is less than think time, wait busy */ | |
3344 | if (cic && sample_valid(cic->ttime_samples) | |
3345 | && (cfqq->slice_end - jiffies < cic->ttime_mean)) | |
3346 | return true; | |
3347 | ||
3348 | /* | |
3349 | * If think times is less than a jiffy than ttime_mean=0 and above | |
3350 | * will not be true. It might happen that slice has not expired yet | |
3351 | * but will expire soon (4-5 ns) during select_queue(). To cover the | |
3352 | * case where think time is less than a jiffy, mark the queue wait | |
3353 | * busy if only 1 jiffy is left in the slice. | |
3354 | */ | |
3355 | if (cfqq->slice_end - jiffies == 1) | |
3356 | return true; | |
3357 | ||
3358 | return false; | |
3359 | } | |
3360 | ||
165125e1 | 3361 | static void cfq_completed_request(struct request_queue *q, struct request *rq) |
1da177e4 | 3362 | { |
5e705374 | 3363 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
b4878f24 | 3364 | struct cfq_data *cfqd = cfqq->cfqd; |
5380a101 | 3365 | const int sync = rq_is_sync(rq); |
b4878f24 | 3366 | unsigned long now; |
1da177e4 | 3367 | |
b4878f24 | 3368 | now = jiffies; |
33659ebb CH |
3369 | cfq_log_cfqq(cfqd, cfqq, "complete rqnoidle %d", |
3370 | !!(rq->cmd_flags & REQ_NOIDLE)); | |
1da177e4 | 3371 | |
45333d5a AC |
3372 | cfq_update_hw_tag(cfqd); |
3373 | ||
53c583d2 | 3374 | WARN_ON(!cfqd->rq_in_driver); |
6d048f53 | 3375 | WARN_ON(!cfqq->dispatched); |
53c583d2 | 3376 | cfqd->rq_in_driver--; |
6d048f53 | 3377 | cfqq->dispatched--; |
e98ef89b VG |
3378 | cfq_blkiocg_update_completion_stats(&cfqq->cfqg->blkg, |
3379 | rq_start_time_ns(rq), rq_io_start_time_ns(rq), | |
3380 | rq_data_dir(rq), rq_is_sync(rq)); | |
1da177e4 | 3381 | |
53c583d2 | 3382 | cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]--; |
3ed9a296 | 3383 | |
365722bb | 3384 | if (sync) { |
5e705374 | 3385 | RQ_CIC(rq)->last_end_request = now; |
573412b2 CZ |
3386 | if (!time_after(rq->start_time + cfqd->cfq_fifo_expire[1], now)) |
3387 | cfqd->last_delayed_sync = now; | |
365722bb | 3388 | } |
caaa5f9f JA |
3389 | |
3390 | /* | |
3391 | * If this is the active queue, check if it needs to be expired, | |
3392 | * or if we want to idle in case it has no pending requests. | |
3393 | */ | |
3394 | if (cfqd->active_queue == cfqq) { | |
a36e71f9 JA |
3395 | const bool cfqq_empty = RB_EMPTY_ROOT(&cfqq->sort_list); |
3396 | ||
44f7c160 JA |
3397 | if (cfq_cfqq_slice_new(cfqq)) { |
3398 | cfq_set_prio_slice(cfqd, cfqq); | |
3399 | cfq_clear_cfqq_slice_new(cfqq); | |
3400 | } | |
f75edf2d VG |
3401 | |
3402 | /* | |
7667aa06 VG |
3403 | * Should we wait for next request to come in before we expire |
3404 | * the queue. | |
f75edf2d | 3405 | */ |
7667aa06 | 3406 | if (cfq_should_wait_busy(cfqd, cfqq)) { |
f75edf2d VG |
3407 | cfqq->slice_end = jiffies + cfqd->cfq_slice_idle; |
3408 | cfq_mark_cfqq_wait_busy(cfqq); | |
b1ffe737 | 3409 | cfq_log_cfqq(cfqd, cfqq, "will busy wait"); |
f75edf2d VG |
3410 | } |
3411 | ||
a36e71f9 | 3412 | /* |
8e550632 CZ |
3413 | * Idling is not enabled on: |
3414 | * - expired queues | |
3415 | * - idle-priority queues | |
3416 | * - async queues | |
3417 | * - queues with still some requests queued | |
3418 | * - when there is a close cooperator | |
a36e71f9 | 3419 | */ |
0871714e | 3420 | if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq)) |
e5ff082e | 3421 | cfq_slice_expired(cfqd, 1); |
8e550632 CZ |
3422 | else if (sync && cfqq_empty && |
3423 | !cfq_close_cooperator(cfqd, cfqq)) { | |
33659ebb CH |
3424 | cfqd->noidle_tree_requires_idle |= |
3425 | !(rq->cmd_flags & REQ_NOIDLE); | |
8e550632 CZ |
3426 | /* |
3427 | * Idling is enabled for SYNC_WORKLOAD. | |
3428 | * SYNC_NOIDLE_WORKLOAD idles at the end of the tree | |
33659ebb | 3429 | * only if we processed at least one !REQ_NOIDLE request |
8e550632 CZ |
3430 | */ |
3431 | if (cfqd->serving_type == SYNC_WORKLOAD | |
c04645e5 VG |
3432 | || cfqd->noidle_tree_requires_idle |
3433 | || cfqq->cfqg->nr_cfqq == 1) | |
8e550632 CZ |
3434 | cfq_arm_slice_timer(cfqd); |
3435 | } | |
caaa5f9f | 3436 | } |
6d048f53 | 3437 | |
53c583d2 | 3438 | if (!cfqd->rq_in_driver) |
23e018a1 | 3439 | cfq_schedule_dispatch(cfqd); |
1da177e4 LT |
3440 | } |
3441 | ||
22e2c507 JA |
3442 | /* |
3443 | * we temporarily boost lower priority queues if they are holding fs exclusive | |
3444 | * resources. they are boosted to normal prio (CLASS_BE/4) | |
3445 | */ | |
3446 | static void cfq_prio_boost(struct cfq_queue *cfqq) | |
1da177e4 | 3447 | { |
22e2c507 JA |
3448 | if (has_fs_excl()) { |
3449 | /* | |
3450 | * boost idle prio on transactions that would lock out other | |
3451 | * users of the filesystem | |
3452 | */ | |
3453 | if (cfq_class_idle(cfqq)) | |
3454 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
3455 | if (cfqq->ioprio > IOPRIO_NORM) | |
3456 | cfqq->ioprio = IOPRIO_NORM; | |
3457 | } else { | |
3458 | /* | |
dddb7451 | 3459 | * unboost the queue (if needed) |
22e2c507 | 3460 | */ |
dddb7451 CZ |
3461 | cfqq->ioprio_class = cfqq->org_ioprio_class; |
3462 | cfqq->ioprio = cfqq->org_ioprio; | |
22e2c507 | 3463 | } |
22e2c507 | 3464 | } |
1da177e4 | 3465 | |
89850f7e | 3466 | static inline int __cfq_may_queue(struct cfq_queue *cfqq) |
22e2c507 | 3467 | { |
1b379d8d | 3468 | if (cfq_cfqq_wait_request(cfqq) && !cfq_cfqq_must_alloc_slice(cfqq)) { |
3b18152c | 3469 | cfq_mark_cfqq_must_alloc_slice(cfqq); |
22e2c507 | 3470 | return ELV_MQUEUE_MUST; |
3b18152c | 3471 | } |
1da177e4 | 3472 | |
22e2c507 | 3473 | return ELV_MQUEUE_MAY; |
22e2c507 JA |
3474 | } |
3475 | ||
165125e1 | 3476 | static int cfq_may_queue(struct request_queue *q, int rw) |
22e2c507 JA |
3477 | { |
3478 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
3479 | struct task_struct *tsk = current; | |
91fac317 | 3480 | struct cfq_io_context *cic; |
22e2c507 JA |
3481 | struct cfq_queue *cfqq; |
3482 | ||
3483 | /* | |
3484 | * don't force setup of a queue from here, as a call to may_queue | |
3485 | * does not necessarily imply that a request actually will be queued. | |
3486 | * so just lookup a possibly existing queue, or return 'may queue' | |
3487 | * if that fails | |
3488 | */ | |
4ac845a2 | 3489 | cic = cfq_cic_lookup(cfqd, tsk->io_context); |
91fac317 VT |
3490 | if (!cic) |
3491 | return ELV_MQUEUE_MAY; | |
3492 | ||
b0b78f81 | 3493 | cfqq = cic_to_cfqq(cic, rw_is_sync(rw)); |
22e2c507 | 3494 | if (cfqq) { |
fd0928df | 3495 | cfq_init_prio_data(cfqq, cic->ioc); |
22e2c507 JA |
3496 | cfq_prio_boost(cfqq); |
3497 | ||
89850f7e | 3498 | return __cfq_may_queue(cfqq); |
22e2c507 JA |
3499 | } |
3500 | ||
3501 | return ELV_MQUEUE_MAY; | |
1da177e4 LT |
3502 | } |
3503 | ||
1da177e4 LT |
3504 | /* |
3505 | * queue lock held here | |
3506 | */ | |
bb37b94c | 3507 | static void cfq_put_request(struct request *rq) |
1da177e4 | 3508 | { |
5e705374 | 3509 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
1da177e4 | 3510 | |
5e705374 | 3511 | if (cfqq) { |
22e2c507 | 3512 | const int rw = rq_data_dir(rq); |
1da177e4 | 3513 | |
22e2c507 JA |
3514 | BUG_ON(!cfqq->allocated[rw]); |
3515 | cfqq->allocated[rw]--; | |
1da177e4 | 3516 | |
5e705374 | 3517 | put_io_context(RQ_CIC(rq)->ioc); |
1da177e4 | 3518 | |
1da177e4 | 3519 | rq->elevator_private = NULL; |
5e705374 | 3520 | rq->elevator_private2 = NULL; |
1da177e4 | 3521 | |
7f1dc8a2 VG |
3522 | /* Put down rq reference on cfqg */ |
3523 | cfq_put_cfqg(RQ_CFQG(rq)); | |
3524 | rq->elevator_private3 = NULL; | |
3525 | ||
1da177e4 LT |
3526 | cfq_put_queue(cfqq); |
3527 | } | |
3528 | } | |
3529 | ||
df5fe3e8 JM |
3530 | static struct cfq_queue * |
3531 | cfq_merge_cfqqs(struct cfq_data *cfqd, struct cfq_io_context *cic, | |
3532 | struct cfq_queue *cfqq) | |
3533 | { | |
3534 | cfq_log_cfqq(cfqd, cfqq, "merging with queue %p", cfqq->new_cfqq); | |
3535 | cic_set_cfqq(cic, cfqq->new_cfqq, 1); | |
b3b6d040 | 3536 | cfq_mark_cfqq_coop(cfqq->new_cfqq); |
df5fe3e8 JM |
3537 | cfq_put_queue(cfqq); |
3538 | return cic_to_cfqq(cic, 1); | |
3539 | } | |
3540 | ||
e6c5bc73 JM |
3541 | /* |
3542 | * Returns NULL if a new cfqq should be allocated, or the old cfqq if this | |
3543 | * was the last process referring to said cfqq. | |
3544 | */ | |
3545 | static struct cfq_queue * | |
3546 | split_cfqq(struct cfq_io_context *cic, struct cfq_queue *cfqq) | |
3547 | { | |
3548 | if (cfqq_process_refs(cfqq) == 1) { | |
e6c5bc73 JM |
3549 | cfqq->pid = current->pid; |
3550 | cfq_clear_cfqq_coop(cfqq); | |
ae54abed | 3551 | cfq_clear_cfqq_split_coop(cfqq); |
e6c5bc73 JM |
3552 | return cfqq; |
3553 | } | |
3554 | ||
3555 | cic_set_cfqq(cic, NULL, 1); | |
d02a2c07 SL |
3556 | |
3557 | cfq_put_cooperator(cfqq); | |
3558 | ||
e6c5bc73 JM |
3559 | cfq_put_queue(cfqq); |
3560 | return NULL; | |
3561 | } | |
1da177e4 | 3562 | /* |
22e2c507 | 3563 | * Allocate cfq data structures associated with this request. |
1da177e4 | 3564 | */ |
22e2c507 | 3565 | static int |
165125e1 | 3566 | cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask) |
1da177e4 LT |
3567 | { |
3568 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
3569 | struct cfq_io_context *cic; | |
3570 | const int rw = rq_data_dir(rq); | |
a6151c3a | 3571 | const bool is_sync = rq_is_sync(rq); |
22e2c507 | 3572 | struct cfq_queue *cfqq; |
1da177e4 LT |
3573 | unsigned long flags; |
3574 | ||
3575 | might_sleep_if(gfp_mask & __GFP_WAIT); | |
3576 | ||
e2d74ac0 | 3577 | cic = cfq_get_io_context(cfqd, gfp_mask); |
22e2c507 | 3578 | |
1da177e4 LT |
3579 | spin_lock_irqsave(q->queue_lock, flags); |
3580 | ||
22e2c507 JA |
3581 | if (!cic) |
3582 | goto queue_fail; | |
3583 | ||
e6c5bc73 | 3584 | new_queue: |
91fac317 | 3585 | cfqq = cic_to_cfqq(cic, is_sync); |
32f2e807 | 3586 | if (!cfqq || cfqq == &cfqd->oom_cfqq) { |
fd0928df | 3587 | cfqq = cfq_get_queue(cfqd, is_sync, cic->ioc, gfp_mask); |
91fac317 | 3588 | cic_set_cfqq(cic, cfqq, is_sync); |
df5fe3e8 | 3589 | } else { |
e6c5bc73 JM |
3590 | /* |
3591 | * If the queue was seeky for too long, break it apart. | |
3592 | */ | |
ae54abed | 3593 | if (cfq_cfqq_coop(cfqq) && cfq_cfqq_split_coop(cfqq)) { |
e6c5bc73 JM |
3594 | cfq_log_cfqq(cfqd, cfqq, "breaking apart cfqq"); |
3595 | cfqq = split_cfqq(cic, cfqq); | |
3596 | if (!cfqq) | |
3597 | goto new_queue; | |
3598 | } | |
3599 | ||
df5fe3e8 JM |
3600 | /* |
3601 | * Check to see if this queue is scheduled to merge with | |
3602 | * another, closely cooperating queue. The merging of | |
3603 | * queues happens here as it must be done in process context. | |
3604 | * The reference on new_cfqq was taken in merge_cfqqs. | |
3605 | */ | |
3606 | if (cfqq->new_cfqq) | |
3607 | cfqq = cfq_merge_cfqqs(cfqd, cic, cfqq); | |
91fac317 | 3608 | } |
1da177e4 LT |
3609 | |
3610 | cfqq->allocated[rw]++; | |
22e2c507 | 3611 | atomic_inc(&cfqq->ref); |
1da177e4 | 3612 | |
5e705374 | 3613 | spin_unlock_irqrestore(q->queue_lock, flags); |
3b18152c | 3614 | |
5e705374 JA |
3615 | rq->elevator_private = cic; |
3616 | rq->elevator_private2 = cfqq; | |
7f1dc8a2 | 3617 | rq->elevator_private3 = cfq_ref_get_cfqg(cfqq->cfqg); |
5e705374 | 3618 | return 0; |
1da177e4 | 3619 | |
22e2c507 JA |
3620 | queue_fail: |
3621 | if (cic) | |
3622 | put_io_context(cic->ioc); | |
89850f7e | 3623 | |
23e018a1 | 3624 | cfq_schedule_dispatch(cfqd); |
1da177e4 | 3625 | spin_unlock_irqrestore(q->queue_lock, flags); |
7b679138 | 3626 | cfq_log(cfqd, "set_request fail"); |
1da177e4 LT |
3627 | return 1; |
3628 | } | |
3629 | ||
65f27f38 | 3630 | static void cfq_kick_queue(struct work_struct *work) |
22e2c507 | 3631 | { |
65f27f38 | 3632 | struct cfq_data *cfqd = |
23e018a1 | 3633 | container_of(work, struct cfq_data, unplug_work); |
165125e1 | 3634 | struct request_queue *q = cfqd->queue; |
22e2c507 | 3635 | |
40bb54d1 | 3636 | spin_lock_irq(q->queue_lock); |
a7f55792 | 3637 | __blk_run_queue(cfqd->queue); |
40bb54d1 | 3638 | spin_unlock_irq(q->queue_lock); |
22e2c507 JA |
3639 | } |
3640 | ||
3641 | /* | |
3642 | * Timer running if the active_queue is currently idling inside its time slice | |
3643 | */ | |
3644 | static void cfq_idle_slice_timer(unsigned long data) | |
3645 | { | |
3646 | struct cfq_data *cfqd = (struct cfq_data *) data; | |
3647 | struct cfq_queue *cfqq; | |
3648 | unsigned long flags; | |
3c6bd2f8 | 3649 | int timed_out = 1; |
22e2c507 | 3650 | |
7b679138 JA |
3651 | cfq_log(cfqd, "idle timer fired"); |
3652 | ||
22e2c507 JA |
3653 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); |
3654 | ||
fe094d98 JA |
3655 | cfqq = cfqd->active_queue; |
3656 | if (cfqq) { | |
3c6bd2f8 JA |
3657 | timed_out = 0; |
3658 | ||
b029195d JA |
3659 | /* |
3660 | * We saw a request before the queue expired, let it through | |
3661 | */ | |
3662 | if (cfq_cfqq_must_dispatch(cfqq)) | |
3663 | goto out_kick; | |
3664 | ||
22e2c507 JA |
3665 | /* |
3666 | * expired | |
3667 | */ | |
44f7c160 | 3668 | if (cfq_slice_used(cfqq)) |
22e2c507 JA |
3669 | goto expire; |
3670 | ||
3671 | /* | |
3672 | * only expire and reinvoke request handler, if there are | |
3673 | * other queues with pending requests | |
3674 | */ | |
caaa5f9f | 3675 | if (!cfqd->busy_queues) |
22e2c507 | 3676 | goto out_cont; |
22e2c507 JA |
3677 | |
3678 | /* | |
3679 | * not expired and it has a request pending, let it dispatch | |
3680 | */ | |
75e50984 | 3681 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
22e2c507 | 3682 | goto out_kick; |
76280aff CZ |
3683 | |
3684 | /* | |
3685 | * Queue depth flag is reset only when the idle didn't succeed | |
3686 | */ | |
3687 | cfq_clear_cfqq_deep(cfqq); | |
22e2c507 JA |
3688 | } |
3689 | expire: | |
e5ff082e | 3690 | cfq_slice_expired(cfqd, timed_out); |
22e2c507 | 3691 | out_kick: |
23e018a1 | 3692 | cfq_schedule_dispatch(cfqd); |
22e2c507 JA |
3693 | out_cont: |
3694 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
3695 | } | |
3696 | ||
3b18152c JA |
3697 | static void cfq_shutdown_timer_wq(struct cfq_data *cfqd) |
3698 | { | |
3699 | del_timer_sync(&cfqd->idle_slice_timer); | |
23e018a1 | 3700 | cancel_work_sync(&cfqd->unplug_work); |
3b18152c | 3701 | } |
22e2c507 | 3702 | |
c2dea2d1 VT |
3703 | static void cfq_put_async_queues(struct cfq_data *cfqd) |
3704 | { | |
3705 | int i; | |
3706 | ||
3707 | for (i = 0; i < IOPRIO_BE_NR; i++) { | |
3708 | if (cfqd->async_cfqq[0][i]) | |
3709 | cfq_put_queue(cfqd->async_cfqq[0][i]); | |
3710 | if (cfqd->async_cfqq[1][i]) | |
3711 | cfq_put_queue(cfqd->async_cfqq[1][i]); | |
c2dea2d1 | 3712 | } |
2389d1ef ON |
3713 | |
3714 | if (cfqd->async_idle_cfqq) | |
3715 | cfq_put_queue(cfqd->async_idle_cfqq); | |
c2dea2d1 VT |
3716 | } |
3717 | ||
bb729bc9 JA |
3718 | static void cfq_cfqd_free(struct rcu_head *head) |
3719 | { | |
3720 | kfree(container_of(head, struct cfq_data, rcu)); | |
3721 | } | |
3722 | ||
b374d18a | 3723 | static void cfq_exit_queue(struct elevator_queue *e) |
1da177e4 | 3724 | { |
22e2c507 | 3725 | struct cfq_data *cfqd = e->elevator_data; |
165125e1 | 3726 | struct request_queue *q = cfqd->queue; |
22e2c507 | 3727 | |
3b18152c | 3728 | cfq_shutdown_timer_wq(cfqd); |
e2d74ac0 | 3729 | |
d9ff4187 | 3730 | spin_lock_irq(q->queue_lock); |
e2d74ac0 | 3731 | |
d9ff4187 | 3732 | if (cfqd->active_queue) |
e5ff082e | 3733 | __cfq_slice_expired(cfqd, cfqd->active_queue, 0); |
e2d74ac0 JA |
3734 | |
3735 | while (!list_empty(&cfqd->cic_list)) { | |
d9ff4187 AV |
3736 | struct cfq_io_context *cic = list_entry(cfqd->cic_list.next, |
3737 | struct cfq_io_context, | |
3738 | queue_list); | |
89850f7e JA |
3739 | |
3740 | __cfq_exit_single_io_context(cfqd, cic); | |
d9ff4187 | 3741 | } |
e2d74ac0 | 3742 | |
c2dea2d1 | 3743 | cfq_put_async_queues(cfqd); |
b1c35769 | 3744 | cfq_release_cfq_groups(cfqd); |
e98ef89b | 3745 | cfq_blkiocg_del_blkio_group(&cfqd->root_group.blkg); |
15c31be4 | 3746 | |
d9ff4187 | 3747 | spin_unlock_irq(q->queue_lock); |
a90d742e AV |
3748 | |
3749 | cfq_shutdown_timer_wq(cfqd); | |
3750 | ||
80b15c73 KK |
3751 | spin_lock(&cic_index_lock); |
3752 | ida_remove(&cic_index_ida, cfqd->cic_index); | |
3753 | spin_unlock(&cic_index_lock); | |
3754 | ||
b1c35769 | 3755 | /* Wait for cfqg->blkg->key accessors to exit their grace periods. */ |
bb729bc9 | 3756 | call_rcu(&cfqd->rcu, cfq_cfqd_free); |
1da177e4 LT |
3757 | } |
3758 | ||
80b15c73 KK |
3759 | static int cfq_alloc_cic_index(void) |
3760 | { | |
3761 | int index, error; | |
3762 | ||
3763 | do { | |
3764 | if (!ida_pre_get(&cic_index_ida, GFP_KERNEL)) | |
3765 | return -ENOMEM; | |
3766 | ||
3767 | spin_lock(&cic_index_lock); | |
3768 | error = ida_get_new(&cic_index_ida, &index); | |
3769 | spin_unlock(&cic_index_lock); | |
3770 | if (error && error != -EAGAIN) | |
3771 | return error; | |
3772 | } while (error); | |
3773 | ||
3774 | return index; | |
3775 | } | |
3776 | ||
165125e1 | 3777 | static void *cfq_init_queue(struct request_queue *q) |
1da177e4 LT |
3778 | { |
3779 | struct cfq_data *cfqd; | |
718eee05 | 3780 | int i, j; |
cdb16e8f | 3781 | struct cfq_group *cfqg; |
615f0259 | 3782 | struct cfq_rb_root *st; |
1da177e4 | 3783 | |
80b15c73 KK |
3784 | i = cfq_alloc_cic_index(); |
3785 | if (i < 0) | |
3786 | return NULL; | |
3787 | ||
94f6030c | 3788 | cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL | __GFP_ZERO, q->node); |
1da177e4 | 3789 | if (!cfqd) |
bc1c1169 | 3790 | return NULL; |
1da177e4 | 3791 | |
80b15c73 KK |
3792 | cfqd->cic_index = i; |
3793 | ||
1fa8f6d6 VG |
3794 | /* Init root service tree */ |
3795 | cfqd->grp_service_tree = CFQ_RB_ROOT; | |
3796 | ||
cdb16e8f VG |
3797 | /* Init root group */ |
3798 | cfqg = &cfqd->root_group; | |
615f0259 VG |
3799 | for_each_cfqg_st(cfqg, i, j, st) |
3800 | *st = CFQ_RB_ROOT; | |
1fa8f6d6 | 3801 | RB_CLEAR_NODE(&cfqg->rb_node); |
26a2ac00 | 3802 | |
25bc6b07 VG |
3803 | /* Give preference to root group over other groups */ |
3804 | cfqg->weight = 2*BLKIO_WEIGHT_DEFAULT; | |
3805 | ||
25fb5169 | 3806 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
b1c35769 VG |
3807 | /* |
3808 | * Take a reference to root group which we never drop. This is just | |
3809 | * to make sure that cfq_put_cfqg() does not try to kfree root group | |
3810 | */ | |
3811 | atomic_set(&cfqg->ref, 1); | |
dcf097b2 | 3812 | rcu_read_lock(); |
e98ef89b VG |
3813 | cfq_blkiocg_add_blkio_group(&blkio_root_cgroup, &cfqg->blkg, |
3814 | (void *)cfqd, 0); | |
dcf097b2 | 3815 | rcu_read_unlock(); |
25fb5169 | 3816 | #endif |
26a2ac00 JA |
3817 | /* |
3818 | * Not strictly needed (since RB_ROOT just clears the node and we | |
3819 | * zeroed cfqd on alloc), but better be safe in case someone decides | |
3820 | * to add magic to the rb code | |
3821 | */ | |
3822 | for (i = 0; i < CFQ_PRIO_LISTS; i++) | |
3823 | cfqd->prio_trees[i] = RB_ROOT; | |
3824 | ||
6118b70b JA |
3825 | /* |
3826 | * Our fallback cfqq if cfq_find_alloc_queue() runs into OOM issues. | |
3827 | * Grab a permanent reference to it, so that the normal code flow | |
3828 | * will not attempt to free it. | |
3829 | */ | |
3830 | cfq_init_cfqq(cfqd, &cfqd->oom_cfqq, 1, 0); | |
3831 | atomic_inc(&cfqd->oom_cfqq.ref); | |
cdb16e8f | 3832 | cfq_link_cfqq_cfqg(&cfqd->oom_cfqq, &cfqd->root_group); |
6118b70b | 3833 | |
d9ff4187 | 3834 | INIT_LIST_HEAD(&cfqd->cic_list); |
1da177e4 | 3835 | |
1da177e4 | 3836 | cfqd->queue = q; |
1da177e4 | 3837 | |
22e2c507 JA |
3838 | init_timer(&cfqd->idle_slice_timer); |
3839 | cfqd->idle_slice_timer.function = cfq_idle_slice_timer; | |
3840 | cfqd->idle_slice_timer.data = (unsigned long) cfqd; | |
3841 | ||
23e018a1 | 3842 | INIT_WORK(&cfqd->unplug_work, cfq_kick_queue); |
22e2c507 | 3843 | |
1da177e4 | 3844 | cfqd->cfq_quantum = cfq_quantum; |
22e2c507 JA |
3845 | cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; |
3846 | cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; | |
1da177e4 LT |
3847 | cfqd->cfq_back_max = cfq_back_max; |
3848 | cfqd->cfq_back_penalty = cfq_back_penalty; | |
22e2c507 JA |
3849 | cfqd->cfq_slice[0] = cfq_slice_async; |
3850 | cfqd->cfq_slice[1] = cfq_slice_sync; | |
3851 | cfqd->cfq_slice_async_rq = cfq_slice_async_rq; | |
3852 | cfqd->cfq_slice_idle = cfq_slice_idle; | |
963b72fc | 3853 | cfqd->cfq_latency = 1; |
ae30c286 | 3854 | cfqd->cfq_group_isolation = 0; |
e459dd08 | 3855 | cfqd->hw_tag = -1; |
edc71131 CZ |
3856 | /* |
3857 | * we optimistically start assuming sync ops weren't delayed in last | |
3858 | * second, in order to have larger depth for async operations. | |
3859 | */ | |
573412b2 | 3860 | cfqd->last_delayed_sync = jiffies - HZ; |
bc1c1169 | 3861 | return cfqd; |
1da177e4 LT |
3862 | } |
3863 | ||
3864 | static void cfq_slab_kill(void) | |
3865 | { | |
d6de8be7 JA |
3866 | /* |
3867 | * Caller already ensured that pending RCU callbacks are completed, | |
3868 | * so we should have no busy allocations at this point. | |
3869 | */ | |
1da177e4 LT |
3870 | if (cfq_pool) |
3871 | kmem_cache_destroy(cfq_pool); | |
3872 | if (cfq_ioc_pool) | |
3873 | kmem_cache_destroy(cfq_ioc_pool); | |
3874 | } | |
3875 | ||
3876 | static int __init cfq_slab_setup(void) | |
3877 | { | |
0a31bd5f | 3878 | cfq_pool = KMEM_CACHE(cfq_queue, 0); |
1da177e4 LT |
3879 | if (!cfq_pool) |
3880 | goto fail; | |
3881 | ||
34e6bbf2 | 3882 | cfq_ioc_pool = KMEM_CACHE(cfq_io_context, 0); |
1da177e4 LT |
3883 | if (!cfq_ioc_pool) |
3884 | goto fail; | |
3885 | ||
3886 | return 0; | |
3887 | fail: | |
3888 | cfq_slab_kill(); | |
3889 | return -ENOMEM; | |
3890 | } | |
3891 | ||
1da177e4 LT |
3892 | /* |
3893 | * sysfs parts below --> | |
3894 | */ | |
1da177e4 LT |
3895 | static ssize_t |
3896 | cfq_var_show(unsigned int var, char *page) | |
3897 | { | |
3898 | return sprintf(page, "%d\n", var); | |
3899 | } | |
3900 | ||
3901 | static ssize_t | |
3902 | cfq_var_store(unsigned int *var, const char *page, size_t count) | |
3903 | { | |
3904 | char *p = (char *) page; | |
3905 | ||
3906 | *var = simple_strtoul(p, &p, 10); | |
3907 | return count; | |
3908 | } | |
3909 | ||
1da177e4 | 3910 | #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ |
b374d18a | 3911 | static ssize_t __FUNC(struct elevator_queue *e, char *page) \ |
1da177e4 | 3912 | { \ |
3d1ab40f | 3913 | struct cfq_data *cfqd = e->elevator_data; \ |
1da177e4 LT |
3914 | unsigned int __data = __VAR; \ |
3915 | if (__CONV) \ | |
3916 | __data = jiffies_to_msecs(__data); \ | |
3917 | return cfq_var_show(__data, (page)); \ | |
3918 | } | |
3919 | SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); | |
22e2c507 JA |
3920 | SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1); |
3921 | SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1); | |
e572ec7e AV |
3922 | SHOW_FUNCTION(cfq_back_seek_max_show, cfqd->cfq_back_max, 0); |
3923 | SHOW_FUNCTION(cfq_back_seek_penalty_show, cfqd->cfq_back_penalty, 0); | |
22e2c507 JA |
3924 | SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1); |
3925 | SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1); | |
3926 | SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1); | |
3927 | SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0); | |
963b72fc | 3928 | SHOW_FUNCTION(cfq_low_latency_show, cfqd->cfq_latency, 0); |
ae30c286 | 3929 | SHOW_FUNCTION(cfq_group_isolation_show, cfqd->cfq_group_isolation, 0); |
1da177e4 LT |
3930 | #undef SHOW_FUNCTION |
3931 | ||
3932 | #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ | |
b374d18a | 3933 | static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \ |
1da177e4 | 3934 | { \ |
3d1ab40f | 3935 | struct cfq_data *cfqd = e->elevator_data; \ |
1da177e4 LT |
3936 | unsigned int __data; \ |
3937 | int ret = cfq_var_store(&__data, (page), count); \ | |
3938 | if (__data < (MIN)) \ | |
3939 | __data = (MIN); \ | |
3940 | else if (__data > (MAX)) \ | |
3941 | __data = (MAX); \ | |
3942 | if (__CONV) \ | |
3943 | *(__PTR) = msecs_to_jiffies(__data); \ | |
3944 | else \ | |
3945 | *(__PTR) = __data; \ | |
3946 | return ret; \ | |
3947 | } | |
3948 | STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); | |
fe094d98 JA |
3949 | STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, |
3950 | UINT_MAX, 1); | |
3951 | STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, | |
3952 | UINT_MAX, 1); | |
e572ec7e | 3953 | STORE_FUNCTION(cfq_back_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); |
fe094d98 JA |
3954 | STORE_FUNCTION(cfq_back_seek_penalty_store, &cfqd->cfq_back_penalty, 1, |
3955 | UINT_MAX, 0); | |
22e2c507 JA |
3956 | STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1); |
3957 | STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1); | |
3958 | STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1); | |
fe094d98 JA |
3959 | STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, |
3960 | UINT_MAX, 0); | |
963b72fc | 3961 | STORE_FUNCTION(cfq_low_latency_store, &cfqd->cfq_latency, 0, 1, 0); |
ae30c286 | 3962 | STORE_FUNCTION(cfq_group_isolation_store, &cfqd->cfq_group_isolation, 0, 1, 0); |
1da177e4 LT |
3963 | #undef STORE_FUNCTION |
3964 | ||
e572ec7e AV |
3965 | #define CFQ_ATTR(name) \ |
3966 | __ATTR(name, S_IRUGO|S_IWUSR, cfq_##name##_show, cfq_##name##_store) | |
3967 | ||
3968 | static struct elv_fs_entry cfq_attrs[] = { | |
3969 | CFQ_ATTR(quantum), | |
e572ec7e AV |
3970 | CFQ_ATTR(fifo_expire_sync), |
3971 | CFQ_ATTR(fifo_expire_async), | |
3972 | CFQ_ATTR(back_seek_max), | |
3973 | CFQ_ATTR(back_seek_penalty), | |
3974 | CFQ_ATTR(slice_sync), | |
3975 | CFQ_ATTR(slice_async), | |
3976 | CFQ_ATTR(slice_async_rq), | |
3977 | CFQ_ATTR(slice_idle), | |
963b72fc | 3978 | CFQ_ATTR(low_latency), |
ae30c286 | 3979 | CFQ_ATTR(group_isolation), |
e572ec7e | 3980 | __ATTR_NULL |
1da177e4 LT |
3981 | }; |
3982 | ||
1da177e4 LT |
3983 | static struct elevator_type iosched_cfq = { |
3984 | .ops = { | |
3985 | .elevator_merge_fn = cfq_merge, | |
3986 | .elevator_merged_fn = cfq_merged_request, | |
3987 | .elevator_merge_req_fn = cfq_merged_requests, | |
da775265 | 3988 | .elevator_allow_merge_fn = cfq_allow_merge, |
812d4026 | 3989 | .elevator_bio_merged_fn = cfq_bio_merged, |
b4878f24 | 3990 | .elevator_dispatch_fn = cfq_dispatch_requests, |
1da177e4 | 3991 | .elevator_add_req_fn = cfq_insert_request, |
b4878f24 | 3992 | .elevator_activate_req_fn = cfq_activate_request, |
1da177e4 LT |
3993 | .elevator_deactivate_req_fn = cfq_deactivate_request, |
3994 | .elevator_queue_empty_fn = cfq_queue_empty, | |
3995 | .elevator_completed_req_fn = cfq_completed_request, | |
21183b07 JA |
3996 | .elevator_former_req_fn = elv_rb_former_request, |
3997 | .elevator_latter_req_fn = elv_rb_latter_request, | |
1da177e4 LT |
3998 | .elevator_set_req_fn = cfq_set_request, |
3999 | .elevator_put_req_fn = cfq_put_request, | |
4000 | .elevator_may_queue_fn = cfq_may_queue, | |
4001 | .elevator_init_fn = cfq_init_queue, | |
4002 | .elevator_exit_fn = cfq_exit_queue, | |
fc46379d | 4003 | .trim = cfq_free_io_context, |
1da177e4 | 4004 | }, |
3d1ab40f | 4005 | .elevator_attrs = cfq_attrs, |
1da177e4 LT |
4006 | .elevator_name = "cfq", |
4007 | .elevator_owner = THIS_MODULE, | |
4008 | }; | |
4009 | ||
3e252066 VG |
4010 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
4011 | static struct blkio_policy_type blkio_policy_cfq = { | |
4012 | .ops = { | |
4013 | .blkio_unlink_group_fn = cfq_unlink_blkio_group, | |
4014 | .blkio_update_group_weight_fn = cfq_update_blkio_group_weight, | |
4015 | }, | |
4016 | }; | |
4017 | #else | |
4018 | static struct blkio_policy_type blkio_policy_cfq; | |
4019 | #endif | |
4020 | ||
1da177e4 LT |
4021 | static int __init cfq_init(void) |
4022 | { | |
22e2c507 JA |
4023 | /* |
4024 | * could be 0 on HZ < 1000 setups | |
4025 | */ | |
4026 | if (!cfq_slice_async) | |
4027 | cfq_slice_async = 1; | |
4028 | if (!cfq_slice_idle) | |
4029 | cfq_slice_idle = 1; | |
4030 | ||
1da177e4 LT |
4031 | if (cfq_slab_setup()) |
4032 | return -ENOMEM; | |
4033 | ||
2fdd82bd | 4034 | elv_register(&iosched_cfq); |
3e252066 | 4035 | blkio_policy_register(&blkio_policy_cfq); |
1da177e4 | 4036 | |
2fdd82bd | 4037 | return 0; |
1da177e4 LT |
4038 | } |
4039 | ||
4040 | static void __exit cfq_exit(void) | |
4041 | { | |
6e9a4738 | 4042 | DECLARE_COMPLETION_ONSTACK(all_gone); |
3e252066 | 4043 | blkio_policy_unregister(&blkio_policy_cfq); |
1da177e4 | 4044 | elv_unregister(&iosched_cfq); |
334e94de | 4045 | ioc_gone = &all_gone; |
fba82272 OH |
4046 | /* ioc_gone's update must be visible before reading ioc_count */ |
4047 | smp_wmb(); | |
d6de8be7 JA |
4048 | |
4049 | /* | |
4050 | * this also protects us from entering cfq_slab_kill() with | |
4051 | * pending RCU callbacks | |
4052 | */ | |
245b2e70 | 4053 | if (elv_ioc_count_read(cfq_ioc_count)) |
9a11b4ed | 4054 | wait_for_completion(&all_gone); |
80b15c73 | 4055 | ida_destroy(&cic_index_ida); |
83521d3e | 4056 | cfq_slab_kill(); |
1da177e4 LT |
4057 | } |
4058 | ||
4059 | module_init(cfq_init); | |
4060 | module_exit(cfq_exit); | |
4061 | ||
4062 | MODULE_AUTHOR("Jens Axboe"); | |
4063 | MODULE_LICENSE("GPL"); | |
4064 | MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler"); |