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Commit | Line | Data |
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1da177e4 | 1 | /* |
1da177e4 LT |
2 | * CFQ, or complete fairness queueing, disk scheduler. |
3 | * | |
4 | * Based on ideas from a previously unfinished io | |
5 | * scheduler (round robin per-process disk scheduling) and Andrea Arcangeli. | |
6 | * | |
0fe23479 | 7 | * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk> |
1da177e4 | 8 | */ |
1da177e4 | 9 | #include <linux/module.h> |
1cc9be68 AV |
10 | #include <linux/blkdev.h> |
11 | #include <linux/elevator.h> | |
1da177e4 | 12 | #include <linux/rbtree.h> |
22e2c507 | 13 | #include <linux/ioprio.h> |
7b679138 | 14 | #include <linux/blktrace_api.h> |
1da177e4 LT |
15 | |
16 | /* | |
17 | * tunables | |
18 | */ | |
fe094d98 JA |
19 | /* max queue in one round of service */ |
20 | static const int cfq_quantum = 4; | |
64100099 | 21 | static const int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 }; |
fe094d98 JA |
22 | /* maximum backwards seek, in KiB */ |
23 | static const int cfq_back_max = 16 * 1024; | |
24 | /* penalty of a backwards seek */ | |
25 | static const int cfq_back_penalty = 2; | |
64100099 | 26 | static const int cfq_slice_sync = HZ / 10; |
3b18152c | 27 | static int cfq_slice_async = HZ / 25; |
64100099 | 28 | static const int cfq_slice_async_rq = 2; |
caaa5f9f | 29 | static int cfq_slice_idle = HZ / 125; |
22e2c507 | 30 | |
d9e7620e | 31 | /* |
0871714e | 32 | * offset from end of service tree |
d9e7620e | 33 | */ |
0871714e | 34 | #define CFQ_IDLE_DELAY (HZ / 5) |
d9e7620e JA |
35 | |
36 | /* | |
37 | * below this threshold, we consider thinktime immediate | |
38 | */ | |
39 | #define CFQ_MIN_TT (2) | |
40 | ||
22e2c507 | 41 | #define CFQ_SLICE_SCALE (5) |
45333d5a | 42 | #define CFQ_HW_QUEUE_MIN (5) |
22e2c507 | 43 | |
fe094d98 JA |
44 | #define RQ_CIC(rq) \ |
45 | ((struct cfq_io_context *) (rq)->elevator_private) | |
7b679138 | 46 | #define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elevator_private2) |
1da177e4 | 47 | |
e18b890b CL |
48 | static struct kmem_cache *cfq_pool; |
49 | static struct kmem_cache *cfq_ioc_pool; | |
1da177e4 | 50 | |
4050cf16 | 51 | static DEFINE_PER_CPU(unsigned long, ioc_count); |
334e94de | 52 | static struct completion *ioc_gone; |
9a11b4ed | 53 | static DEFINE_SPINLOCK(ioc_gone_lock); |
334e94de | 54 | |
22e2c507 JA |
55 | #define CFQ_PRIO_LISTS IOPRIO_BE_NR |
56 | #define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE) | |
22e2c507 JA |
57 | #define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT) |
58 | ||
206dc69b JA |
59 | #define sample_valid(samples) ((samples) > 80) |
60 | ||
cc09e299 JA |
61 | /* |
62 | * Most of our rbtree usage is for sorting with min extraction, so | |
63 | * if we cache the leftmost node we don't have to walk down the tree | |
64 | * to find it. Idea borrowed from Ingo Molnars CFS scheduler. We should | |
65 | * move this into the elevator for the rq sorting as well. | |
66 | */ | |
67 | struct cfq_rb_root { | |
68 | struct rb_root rb; | |
69 | struct rb_node *left; | |
70 | }; | |
71 | #define CFQ_RB_ROOT (struct cfq_rb_root) { RB_ROOT, NULL, } | |
72 | ||
22e2c507 JA |
73 | /* |
74 | * Per block device queue structure | |
75 | */ | |
1da177e4 | 76 | struct cfq_data { |
165125e1 | 77 | struct request_queue *queue; |
22e2c507 JA |
78 | |
79 | /* | |
80 | * rr list of queues with requests and the count of them | |
81 | */ | |
cc09e299 | 82 | struct cfq_rb_root service_tree; |
22e2c507 | 83 | unsigned int busy_queues; |
3a9a3f6c DS |
84 | /* |
85 | * Used to track any pending rt requests so we can pre-empt current | |
86 | * non-RT cfqq in service when this value is non-zero. | |
87 | */ | |
88 | unsigned int busy_rt_queues; | |
22e2c507 | 89 | |
22e2c507 | 90 | int rq_in_driver; |
3ed9a296 | 91 | int sync_flight; |
45333d5a AC |
92 | |
93 | /* | |
94 | * queue-depth detection | |
95 | */ | |
96 | int rq_queued; | |
25776e35 | 97 | int hw_tag; |
45333d5a AC |
98 | int hw_tag_samples; |
99 | int rq_in_driver_peak; | |
1da177e4 | 100 | |
22e2c507 JA |
101 | /* |
102 | * idle window management | |
103 | */ | |
104 | struct timer_list idle_slice_timer; | |
105 | struct work_struct unplug_work; | |
1da177e4 | 106 | |
22e2c507 JA |
107 | struct cfq_queue *active_queue; |
108 | struct cfq_io_context *active_cic; | |
22e2c507 | 109 | |
c2dea2d1 VT |
110 | /* |
111 | * async queue for each priority case | |
112 | */ | |
113 | struct cfq_queue *async_cfqq[2][IOPRIO_BE_NR]; | |
114 | struct cfq_queue *async_idle_cfqq; | |
15c31be4 | 115 | |
6d048f53 | 116 | sector_t last_position; |
22e2c507 | 117 | unsigned long last_end_request; |
1da177e4 | 118 | |
1da177e4 LT |
119 | /* |
120 | * tunables, see top of file | |
121 | */ | |
122 | unsigned int cfq_quantum; | |
22e2c507 | 123 | unsigned int cfq_fifo_expire[2]; |
1da177e4 LT |
124 | unsigned int cfq_back_penalty; |
125 | unsigned int cfq_back_max; | |
22e2c507 JA |
126 | unsigned int cfq_slice[2]; |
127 | unsigned int cfq_slice_async_rq; | |
128 | unsigned int cfq_slice_idle; | |
d9ff4187 AV |
129 | |
130 | struct list_head cic_list; | |
1da177e4 LT |
131 | }; |
132 | ||
22e2c507 JA |
133 | /* |
134 | * Per process-grouping structure | |
135 | */ | |
1da177e4 LT |
136 | struct cfq_queue { |
137 | /* reference count */ | |
138 | atomic_t ref; | |
be754d2c RK |
139 | /* various state flags, see below */ |
140 | unsigned int flags; | |
1da177e4 LT |
141 | /* parent cfq_data */ |
142 | struct cfq_data *cfqd; | |
d9e7620e JA |
143 | /* service_tree member */ |
144 | struct rb_node rb_node; | |
145 | /* service_tree key */ | |
146 | unsigned long rb_key; | |
1da177e4 LT |
147 | /* sorted list of pending requests */ |
148 | struct rb_root sort_list; | |
149 | /* if fifo isn't expired, next request to serve */ | |
5e705374 | 150 | struct request *next_rq; |
1da177e4 LT |
151 | /* requests queued in sort_list */ |
152 | int queued[2]; | |
153 | /* currently allocated requests */ | |
154 | int allocated[2]; | |
155 | /* fifo list of requests in sort_list */ | |
22e2c507 | 156 | struct list_head fifo; |
1da177e4 | 157 | |
22e2c507 | 158 | unsigned long slice_end; |
c5b680f3 | 159 | long slice_resid; |
2f5cb738 | 160 | unsigned int slice_dispatch; |
1da177e4 | 161 | |
be754d2c RK |
162 | /* pending metadata requests */ |
163 | int meta_pending; | |
6d048f53 JA |
164 | /* number of requests that are on the dispatch list or inside driver */ |
165 | int dispatched; | |
22e2c507 JA |
166 | |
167 | /* io prio of this group */ | |
168 | unsigned short ioprio, org_ioprio; | |
169 | unsigned short ioprio_class, org_ioprio_class; | |
170 | ||
7b679138 | 171 | pid_t pid; |
1da177e4 LT |
172 | }; |
173 | ||
3b18152c | 174 | enum cfqq_state_flags { |
b0b8d749 JA |
175 | CFQ_CFQQ_FLAG_on_rr = 0, /* on round-robin busy list */ |
176 | CFQ_CFQQ_FLAG_wait_request, /* waiting for a request */ | |
b029195d | 177 | CFQ_CFQQ_FLAG_must_dispatch, /* must be allowed a dispatch */ |
b0b8d749 JA |
178 | CFQ_CFQQ_FLAG_must_alloc, /* must be allowed rq alloc */ |
179 | CFQ_CFQQ_FLAG_must_alloc_slice, /* per-slice must_alloc flag */ | |
b0b8d749 JA |
180 | CFQ_CFQQ_FLAG_fifo_expire, /* FIFO checked in this slice */ |
181 | CFQ_CFQQ_FLAG_idle_window, /* slice idling enabled */ | |
182 | CFQ_CFQQ_FLAG_prio_changed, /* task priority has changed */ | |
44f7c160 | 183 | CFQ_CFQQ_FLAG_slice_new, /* no requests dispatched in slice */ |
91fac317 | 184 | CFQ_CFQQ_FLAG_sync, /* synchronous queue */ |
3b18152c JA |
185 | }; |
186 | ||
187 | #define CFQ_CFQQ_FNS(name) \ | |
188 | static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \ | |
189 | { \ | |
fe094d98 | 190 | (cfqq)->flags |= (1 << CFQ_CFQQ_FLAG_##name); \ |
3b18152c JA |
191 | } \ |
192 | static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \ | |
193 | { \ | |
fe094d98 | 194 | (cfqq)->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \ |
3b18152c JA |
195 | } \ |
196 | static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \ | |
197 | { \ | |
fe094d98 | 198 | return ((cfqq)->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \ |
3b18152c JA |
199 | } |
200 | ||
201 | CFQ_CFQQ_FNS(on_rr); | |
202 | CFQ_CFQQ_FNS(wait_request); | |
b029195d | 203 | CFQ_CFQQ_FNS(must_dispatch); |
3b18152c JA |
204 | CFQ_CFQQ_FNS(must_alloc); |
205 | CFQ_CFQQ_FNS(must_alloc_slice); | |
3b18152c JA |
206 | CFQ_CFQQ_FNS(fifo_expire); |
207 | CFQ_CFQQ_FNS(idle_window); | |
208 | CFQ_CFQQ_FNS(prio_changed); | |
44f7c160 | 209 | CFQ_CFQQ_FNS(slice_new); |
91fac317 | 210 | CFQ_CFQQ_FNS(sync); |
3b18152c JA |
211 | #undef CFQ_CFQQ_FNS |
212 | ||
7b679138 JA |
213 | #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \ |
214 | blk_add_trace_msg((cfqd)->queue, "cfq%d " fmt, (cfqq)->pid, ##args) | |
215 | #define cfq_log(cfqd, fmt, args...) \ | |
216 | blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args) | |
217 | ||
165125e1 | 218 | static void cfq_dispatch_insert(struct request_queue *, struct request *); |
91fac317 | 219 | static struct cfq_queue *cfq_get_queue(struct cfq_data *, int, |
fd0928df | 220 | struct io_context *, gfp_t); |
4ac845a2 | 221 | static struct cfq_io_context *cfq_cic_lookup(struct cfq_data *, |
91fac317 VT |
222 | struct io_context *); |
223 | ||
224 | static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_context *cic, | |
225 | int is_sync) | |
226 | { | |
227 | return cic->cfqq[!!is_sync]; | |
228 | } | |
229 | ||
230 | static inline void cic_set_cfqq(struct cfq_io_context *cic, | |
231 | struct cfq_queue *cfqq, int is_sync) | |
232 | { | |
233 | cic->cfqq[!!is_sync] = cfqq; | |
234 | } | |
235 | ||
236 | /* | |
237 | * We regard a request as SYNC, if it's either a read or has the SYNC bit | |
238 | * set (in which case it could also be direct WRITE). | |
239 | */ | |
240 | static inline int cfq_bio_sync(struct bio *bio) | |
241 | { | |
242 | if (bio_data_dir(bio) == READ || bio_sync(bio)) | |
243 | return 1; | |
244 | ||
245 | return 0; | |
246 | } | |
1da177e4 | 247 | |
99f95e52 AM |
248 | /* |
249 | * scheduler run of queue, if there are requests pending and no one in the | |
250 | * driver that will restart queueing | |
251 | */ | |
252 | static inline void cfq_schedule_dispatch(struct cfq_data *cfqd) | |
253 | { | |
7b679138 JA |
254 | if (cfqd->busy_queues) { |
255 | cfq_log(cfqd, "schedule dispatch"); | |
18887ad9 | 256 | kblockd_schedule_work(cfqd->queue, &cfqd->unplug_work); |
7b679138 | 257 | } |
99f95e52 AM |
258 | } |
259 | ||
165125e1 | 260 | static int cfq_queue_empty(struct request_queue *q) |
99f95e52 AM |
261 | { |
262 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
263 | ||
b4878f24 | 264 | return !cfqd->busy_queues; |
99f95e52 AM |
265 | } |
266 | ||
44f7c160 JA |
267 | /* |
268 | * Scale schedule slice based on io priority. Use the sync time slice only | |
269 | * if a queue is marked sync and has sync io queued. A sync queue with async | |
270 | * io only, should not get full sync slice length. | |
271 | */ | |
d9e7620e JA |
272 | static inline int cfq_prio_slice(struct cfq_data *cfqd, int sync, |
273 | unsigned short prio) | |
44f7c160 | 274 | { |
d9e7620e | 275 | const int base_slice = cfqd->cfq_slice[sync]; |
44f7c160 | 276 | |
d9e7620e JA |
277 | WARN_ON(prio >= IOPRIO_BE_NR); |
278 | ||
279 | return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - prio)); | |
280 | } | |
44f7c160 | 281 | |
d9e7620e JA |
282 | static inline int |
283 | cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
284 | { | |
285 | return cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio); | |
44f7c160 JA |
286 | } |
287 | ||
288 | static inline void | |
289 | cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
290 | { | |
291 | cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies; | |
7b679138 | 292 | cfq_log_cfqq(cfqd, cfqq, "set_slice=%lu", cfqq->slice_end - jiffies); |
44f7c160 JA |
293 | } |
294 | ||
295 | /* | |
296 | * We need to wrap this check in cfq_cfqq_slice_new(), since ->slice_end | |
297 | * isn't valid until the first request from the dispatch is activated | |
298 | * and the slice time set. | |
299 | */ | |
300 | static inline int cfq_slice_used(struct cfq_queue *cfqq) | |
301 | { | |
302 | if (cfq_cfqq_slice_new(cfqq)) | |
303 | return 0; | |
304 | if (time_before(jiffies, cfqq->slice_end)) | |
305 | return 0; | |
306 | ||
307 | return 1; | |
308 | } | |
309 | ||
1da177e4 | 310 | /* |
5e705374 | 311 | * Lifted from AS - choose which of rq1 and rq2 that is best served now. |
1da177e4 | 312 | * We choose the request that is closest to the head right now. Distance |
e8a99053 | 313 | * behind the head is penalized and only allowed to a certain extent. |
1da177e4 | 314 | */ |
5e705374 JA |
315 | static struct request * |
316 | cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2) | |
1da177e4 LT |
317 | { |
318 | sector_t last, s1, s2, d1 = 0, d2 = 0; | |
1da177e4 | 319 | unsigned long back_max; |
e8a99053 AM |
320 | #define CFQ_RQ1_WRAP 0x01 /* request 1 wraps */ |
321 | #define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */ | |
322 | unsigned wrap = 0; /* bit mask: requests behind the disk head? */ | |
1da177e4 | 323 | |
5e705374 JA |
324 | if (rq1 == NULL || rq1 == rq2) |
325 | return rq2; | |
326 | if (rq2 == NULL) | |
327 | return rq1; | |
9c2c38a1 | 328 | |
5e705374 JA |
329 | if (rq_is_sync(rq1) && !rq_is_sync(rq2)) |
330 | return rq1; | |
331 | else if (rq_is_sync(rq2) && !rq_is_sync(rq1)) | |
332 | return rq2; | |
374f84ac JA |
333 | if (rq_is_meta(rq1) && !rq_is_meta(rq2)) |
334 | return rq1; | |
335 | else if (rq_is_meta(rq2) && !rq_is_meta(rq1)) | |
336 | return rq2; | |
1da177e4 | 337 | |
5e705374 JA |
338 | s1 = rq1->sector; |
339 | s2 = rq2->sector; | |
1da177e4 | 340 | |
6d048f53 | 341 | last = cfqd->last_position; |
1da177e4 | 342 | |
1da177e4 LT |
343 | /* |
344 | * by definition, 1KiB is 2 sectors | |
345 | */ | |
346 | back_max = cfqd->cfq_back_max * 2; | |
347 | ||
348 | /* | |
349 | * Strict one way elevator _except_ in the case where we allow | |
350 | * short backward seeks which are biased as twice the cost of a | |
351 | * similar forward seek. | |
352 | */ | |
353 | if (s1 >= last) | |
354 | d1 = s1 - last; | |
355 | else if (s1 + back_max >= last) | |
356 | d1 = (last - s1) * cfqd->cfq_back_penalty; | |
357 | else | |
e8a99053 | 358 | wrap |= CFQ_RQ1_WRAP; |
1da177e4 LT |
359 | |
360 | if (s2 >= last) | |
361 | d2 = s2 - last; | |
362 | else if (s2 + back_max >= last) | |
363 | d2 = (last - s2) * cfqd->cfq_back_penalty; | |
364 | else | |
e8a99053 | 365 | wrap |= CFQ_RQ2_WRAP; |
1da177e4 LT |
366 | |
367 | /* Found required data */ | |
e8a99053 AM |
368 | |
369 | /* | |
370 | * By doing switch() on the bit mask "wrap" we avoid having to | |
371 | * check two variables for all permutations: --> faster! | |
372 | */ | |
373 | switch (wrap) { | |
5e705374 | 374 | case 0: /* common case for CFQ: rq1 and rq2 not wrapped */ |
e8a99053 | 375 | if (d1 < d2) |
5e705374 | 376 | return rq1; |
e8a99053 | 377 | else if (d2 < d1) |
5e705374 | 378 | return rq2; |
e8a99053 AM |
379 | else { |
380 | if (s1 >= s2) | |
5e705374 | 381 | return rq1; |
e8a99053 | 382 | else |
5e705374 | 383 | return rq2; |
e8a99053 | 384 | } |
1da177e4 | 385 | |
e8a99053 | 386 | case CFQ_RQ2_WRAP: |
5e705374 | 387 | return rq1; |
e8a99053 | 388 | case CFQ_RQ1_WRAP: |
5e705374 JA |
389 | return rq2; |
390 | case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both rqs wrapped */ | |
e8a99053 AM |
391 | default: |
392 | /* | |
393 | * Since both rqs are wrapped, | |
394 | * start with the one that's further behind head | |
395 | * (--> only *one* back seek required), | |
396 | * since back seek takes more time than forward. | |
397 | */ | |
398 | if (s1 <= s2) | |
5e705374 | 399 | return rq1; |
1da177e4 | 400 | else |
5e705374 | 401 | return rq2; |
1da177e4 LT |
402 | } |
403 | } | |
404 | ||
498d3aa2 JA |
405 | /* |
406 | * The below is leftmost cache rbtree addon | |
407 | */ | |
0871714e | 408 | static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root) |
cc09e299 JA |
409 | { |
410 | if (!root->left) | |
411 | root->left = rb_first(&root->rb); | |
412 | ||
0871714e JA |
413 | if (root->left) |
414 | return rb_entry(root->left, struct cfq_queue, rb_node); | |
415 | ||
416 | return NULL; | |
cc09e299 JA |
417 | } |
418 | ||
419 | static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root) | |
420 | { | |
421 | if (root->left == n) | |
422 | root->left = NULL; | |
423 | ||
424 | rb_erase(n, &root->rb); | |
425 | RB_CLEAR_NODE(n); | |
426 | } | |
427 | ||
1da177e4 LT |
428 | /* |
429 | * would be nice to take fifo expire time into account as well | |
430 | */ | |
5e705374 JA |
431 | static struct request * |
432 | cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
433 | struct request *last) | |
1da177e4 | 434 | { |
21183b07 JA |
435 | struct rb_node *rbnext = rb_next(&last->rb_node); |
436 | struct rb_node *rbprev = rb_prev(&last->rb_node); | |
5e705374 | 437 | struct request *next = NULL, *prev = NULL; |
1da177e4 | 438 | |
21183b07 | 439 | BUG_ON(RB_EMPTY_NODE(&last->rb_node)); |
1da177e4 LT |
440 | |
441 | if (rbprev) | |
5e705374 | 442 | prev = rb_entry_rq(rbprev); |
1da177e4 | 443 | |
21183b07 | 444 | if (rbnext) |
5e705374 | 445 | next = rb_entry_rq(rbnext); |
21183b07 JA |
446 | else { |
447 | rbnext = rb_first(&cfqq->sort_list); | |
448 | if (rbnext && rbnext != &last->rb_node) | |
5e705374 | 449 | next = rb_entry_rq(rbnext); |
21183b07 | 450 | } |
1da177e4 | 451 | |
21183b07 | 452 | return cfq_choose_req(cfqd, next, prev); |
1da177e4 LT |
453 | } |
454 | ||
d9e7620e JA |
455 | static unsigned long cfq_slice_offset(struct cfq_data *cfqd, |
456 | struct cfq_queue *cfqq) | |
1da177e4 | 457 | { |
d9e7620e JA |
458 | /* |
459 | * just an approximation, should be ok. | |
460 | */ | |
67e6b49e JA |
461 | return (cfqd->busy_queues - 1) * (cfq_prio_slice(cfqd, 1, 0) - |
462 | cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio)); | |
d9e7620e JA |
463 | } |
464 | ||
498d3aa2 JA |
465 | /* |
466 | * The cfqd->service_tree holds all pending cfq_queue's that have | |
467 | * requests waiting to be processed. It is sorted in the order that | |
468 | * we will service the queues. | |
469 | */ | |
d9e7620e | 470 | static void cfq_service_tree_add(struct cfq_data *cfqd, |
edd75ffd | 471 | struct cfq_queue *cfqq, int add_front) |
d9e7620e | 472 | { |
0871714e JA |
473 | struct rb_node **p, *parent; |
474 | struct cfq_queue *__cfqq; | |
d9e7620e | 475 | unsigned long rb_key; |
498d3aa2 | 476 | int left; |
d9e7620e | 477 | |
0871714e JA |
478 | if (cfq_class_idle(cfqq)) { |
479 | rb_key = CFQ_IDLE_DELAY; | |
480 | parent = rb_last(&cfqd->service_tree.rb); | |
481 | if (parent && parent != &cfqq->rb_node) { | |
482 | __cfqq = rb_entry(parent, struct cfq_queue, rb_node); | |
483 | rb_key += __cfqq->rb_key; | |
484 | } else | |
485 | rb_key += jiffies; | |
486 | } else if (!add_front) { | |
edd75ffd JA |
487 | rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies; |
488 | rb_key += cfqq->slice_resid; | |
489 | cfqq->slice_resid = 0; | |
490 | } else | |
491 | rb_key = 0; | |
1da177e4 | 492 | |
d9e7620e | 493 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) { |
99f9628a | 494 | /* |
d9e7620e | 495 | * same position, nothing more to do |
99f9628a | 496 | */ |
d9e7620e JA |
497 | if (rb_key == cfqq->rb_key) |
498 | return; | |
1da177e4 | 499 | |
cc09e299 | 500 | cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree); |
1da177e4 | 501 | } |
d9e7620e | 502 | |
498d3aa2 | 503 | left = 1; |
0871714e JA |
504 | parent = NULL; |
505 | p = &cfqd->service_tree.rb.rb_node; | |
d9e7620e | 506 | while (*p) { |
67060e37 | 507 | struct rb_node **n; |
cc09e299 | 508 | |
d9e7620e JA |
509 | parent = *p; |
510 | __cfqq = rb_entry(parent, struct cfq_queue, rb_node); | |
511 | ||
0c534e0a JA |
512 | /* |
513 | * sort RT queues first, we always want to give | |
67060e37 JA |
514 | * preference to them. IDLE queues goes to the back. |
515 | * after that, sort on the next service time. | |
0c534e0a JA |
516 | */ |
517 | if (cfq_class_rt(cfqq) > cfq_class_rt(__cfqq)) | |
67060e37 | 518 | n = &(*p)->rb_left; |
0c534e0a | 519 | else if (cfq_class_rt(cfqq) < cfq_class_rt(__cfqq)) |
67060e37 JA |
520 | n = &(*p)->rb_right; |
521 | else if (cfq_class_idle(cfqq) < cfq_class_idle(__cfqq)) | |
522 | n = &(*p)->rb_left; | |
523 | else if (cfq_class_idle(cfqq) > cfq_class_idle(__cfqq)) | |
524 | n = &(*p)->rb_right; | |
0c534e0a | 525 | else if (rb_key < __cfqq->rb_key) |
67060e37 JA |
526 | n = &(*p)->rb_left; |
527 | else | |
528 | n = &(*p)->rb_right; | |
529 | ||
530 | if (n == &(*p)->rb_right) | |
cc09e299 | 531 | left = 0; |
67060e37 JA |
532 | |
533 | p = n; | |
d9e7620e JA |
534 | } |
535 | ||
cc09e299 JA |
536 | if (left) |
537 | cfqd->service_tree.left = &cfqq->rb_node; | |
538 | ||
d9e7620e JA |
539 | cfqq->rb_key = rb_key; |
540 | rb_link_node(&cfqq->rb_node, parent, p); | |
cc09e299 | 541 | rb_insert_color(&cfqq->rb_node, &cfqd->service_tree.rb); |
1da177e4 LT |
542 | } |
543 | ||
498d3aa2 JA |
544 | /* |
545 | * Update cfqq's position in the service tree. | |
546 | */ | |
edd75ffd | 547 | static void cfq_resort_rr_list(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
6d048f53 | 548 | { |
6d048f53 JA |
549 | /* |
550 | * Resorting requires the cfqq to be on the RR list already. | |
551 | */ | |
498d3aa2 | 552 | if (cfq_cfqq_on_rr(cfqq)) |
edd75ffd | 553 | cfq_service_tree_add(cfqd, cfqq, 0); |
6d048f53 JA |
554 | } |
555 | ||
1da177e4 LT |
556 | /* |
557 | * add to busy list of queues for service, trying to be fair in ordering | |
22e2c507 | 558 | * the pending list according to last request service |
1da177e4 | 559 | */ |
febffd61 | 560 | static void cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 561 | { |
7b679138 | 562 | cfq_log_cfqq(cfqd, cfqq, "add_to_rr"); |
3b18152c JA |
563 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
564 | cfq_mark_cfqq_on_rr(cfqq); | |
1da177e4 | 565 | cfqd->busy_queues++; |
3a9a3f6c DS |
566 | if (cfq_class_rt(cfqq)) |
567 | cfqd->busy_rt_queues++; | |
1da177e4 | 568 | |
edd75ffd | 569 | cfq_resort_rr_list(cfqd, cfqq); |
1da177e4 LT |
570 | } |
571 | ||
498d3aa2 JA |
572 | /* |
573 | * Called when the cfqq no longer has requests pending, remove it from | |
574 | * the service tree. | |
575 | */ | |
febffd61 | 576 | static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 577 | { |
7b679138 | 578 | cfq_log_cfqq(cfqd, cfqq, "del_from_rr"); |
3b18152c JA |
579 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
580 | cfq_clear_cfqq_on_rr(cfqq); | |
1da177e4 | 581 | |
cc09e299 JA |
582 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) |
583 | cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree); | |
d9e7620e | 584 | |
1da177e4 LT |
585 | BUG_ON(!cfqd->busy_queues); |
586 | cfqd->busy_queues--; | |
3a9a3f6c DS |
587 | if (cfq_class_rt(cfqq)) |
588 | cfqd->busy_rt_queues--; | |
1da177e4 LT |
589 | } |
590 | ||
591 | /* | |
592 | * rb tree support functions | |
593 | */ | |
febffd61 | 594 | static void cfq_del_rq_rb(struct request *rq) |
1da177e4 | 595 | { |
5e705374 | 596 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
b4878f24 | 597 | struct cfq_data *cfqd = cfqq->cfqd; |
5e705374 | 598 | const int sync = rq_is_sync(rq); |
1da177e4 | 599 | |
b4878f24 JA |
600 | BUG_ON(!cfqq->queued[sync]); |
601 | cfqq->queued[sync]--; | |
1da177e4 | 602 | |
5e705374 | 603 | elv_rb_del(&cfqq->sort_list, rq); |
1da177e4 | 604 | |
dd67d051 | 605 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) |
b4878f24 | 606 | cfq_del_cfqq_rr(cfqd, cfqq); |
1da177e4 LT |
607 | } |
608 | ||
5e705374 | 609 | static void cfq_add_rq_rb(struct request *rq) |
1da177e4 | 610 | { |
5e705374 | 611 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
1da177e4 | 612 | struct cfq_data *cfqd = cfqq->cfqd; |
21183b07 | 613 | struct request *__alias; |
1da177e4 | 614 | |
5380a101 | 615 | cfqq->queued[rq_is_sync(rq)]++; |
1da177e4 LT |
616 | |
617 | /* | |
618 | * looks a little odd, but the first insert might return an alias. | |
619 | * if that happens, put the alias on the dispatch list | |
620 | */ | |
21183b07 | 621 | while ((__alias = elv_rb_add(&cfqq->sort_list, rq)) != NULL) |
5e705374 | 622 | cfq_dispatch_insert(cfqd->queue, __alias); |
5fccbf61 JA |
623 | |
624 | if (!cfq_cfqq_on_rr(cfqq)) | |
625 | cfq_add_cfqq_rr(cfqd, cfqq); | |
5044eed4 JA |
626 | |
627 | /* | |
628 | * check if this request is a better next-serve candidate | |
629 | */ | |
630 | cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq); | |
631 | BUG_ON(!cfqq->next_rq); | |
1da177e4 LT |
632 | } |
633 | ||
febffd61 | 634 | static void cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq) |
1da177e4 | 635 | { |
5380a101 JA |
636 | elv_rb_del(&cfqq->sort_list, rq); |
637 | cfqq->queued[rq_is_sync(rq)]--; | |
5e705374 | 638 | cfq_add_rq_rb(rq); |
1da177e4 LT |
639 | } |
640 | ||
206dc69b JA |
641 | static struct request * |
642 | cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio) | |
1da177e4 | 643 | { |
206dc69b | 644 | struct task_struct *tsk = current; |
91fac317 | 645 | struct cfq_io_context *cic; |
206dc69b | 646 | struct cfq_queue *cfqq; |
1da177e4 | 647 | |
4ac845a2 | 648 | cic = cfq_cic_lookup(cfqd, tsk->io_context); |
91fac317 VT |
649 | if (!cic) |
650 | return NULL; | |
651 | ||
652 | cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); | |
89850f7e JA |
653 | if (cfqq) { |
654 | sector_t sector = bio->bi_sector + bio_sectors(bio); | |
655 | ||
21183b07 | 656 | return elv_rb_find(&cfqq->sort_list, sector); |
89850f7e | 657 | } |
1da177e4 | 658 | |
1da177e4 LT |
659 | return NULL; |
660 | } | |
661 | ||
165125e1 | 662 | static void cfq_activate_request(struct request_queue *q, struct request *rq) |
1da177e4 | 663 | { |
22e2c507 | 664 | struct cfq_data *cfqd = q->elevator->elevator_data; |
3b18152c | 665 | |
b4878f24 | 666 | cfqd->rq_in_driver++; |
7b679138 JA |
667 | cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "activate rq, drv=%d", |
668 | cfqd->rq_in_driver); | |
25776e35 | 669 | |
6d048f53 | 670 | cfqd->last_position = rq->hard_sector + rq->hard_nr_sectors; |
1da177e4 LT |
671 | } |
672 | ||
165125e1 | 673 | static void cfq_deactivate_request(struct request_queue *q, struct request *rq) |
1da177e4 | 674 | { |
b4878f24 JA |
675 | struct cfq_data *cfqd = q->elevator->elevator_data; |
676 | ||
677 | WARN_ON(!cfqd->rq_in_driver); | |
678 | cfqd->rq_in_driver--; | |
7b679138 JA |
679 | cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "deactivate rq, drv=%d", |
680 | cfqd->rq_in_driver); | |
1da177e4 LT |
681 | } |
682 | ||
b4878f24 | 683 | static void cfq_remove_request(struct request *rq) |
1da177e4 | 684 | { |
5e705374 | 685 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
21183b07 | 686 | |
5e705374 JA |
687 | if (cfqq->next_rq == rq) |
688 | cfqq->next_rq = cfq_find_next_rq(cfqq->cfqd, cfqq, rq); | |
1da177e4 | 689 | |
b4878f24 | 690 | list_del_init(&rq->queuelist); |
5e705374 | 691 | cfq_del_rq_rb(rq); |
374f84ac | 692 | |
45333d5a | 693 | cfqq->cfqd->rq_queued--; |
374f84ac JA |
694 | if (rq_is_meta(rq)) { |
695 | WARN_ON(!cfqq->meta_pending); | |
696 | cfqq->meta_pending--; | |
697 | } | |
1da177e4 LT |
698 | } |
699 | ||
165125e1 JA |
700 | static int cfq_merge(struct request_queue *q, struct request **req, |
701 | struct bio *bio) | |
1da177e4 LT |
702 | { |
703 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
704 | struct request *__rq; | |
1da177e4 | 705 | |
206dc69b | 706 | __rq = cfq_find_rq_fmerge(cfqd, bio); |
22e2c507 | 707 | if (__rq && elv_rq_merge_ok(__rq, bio)) { |
9817064b JA |
708 | *req = __rq; |
709 | return ELEVATOR_FRONT_MERGE; | |
1da177e4 LT |
710 | } |
711 | ||
712 | return ELEVATOR_NO_MERGE; | |
1da177e4 LT |
713 | } |
714 | ||
165125e1 | 715 | static void cfq_merged_request(struct request_queue *q, struct request *req, |
21183b07 | 716 | int type) |
1da177e4 | 717 | { |
21183b07 | 718 | if (type == ELEVATOR_FRONT_MERGE) { |
5e705374 | 719 | struct cfq_queue *cfqq = RQ_CFQQ(req); |
1da177e4 | 720 | |
5e705374 | 721 | cfq_reposition_rq_rb(cfqq, req); |
1da177e4 | 722 | } |
1da177e4 LT |
723 | } |
724 | ||
725 | static void | |
165125e1 | 726 | cfq_merged_requests(struct request_queue *q, struct request *rq, |
1da177e4 LT |
727 | struct request *next) |
728 | { | |
22e2c507 JA |
729 | /* |
730 | * reposition in fifo if next is older than rq | |
731 | */ | |
732 | if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && | |
733 | time_before(next->start_time, rq->start_time)) | |
734 | list_move(&rq->queuelist, &next->queuelist); | |
735 | ||
b4878f24 | 736 | cfq_remove_request(next); |
22e2c507 JA |
737 | } |
738 | ||
165125e1 | 739 | static int cfq_allow_merge(struct request_queue *q, struct request *rq, |
da775265 JA |
740 | struct bio *bio) |
741 | { | |
742 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
91fac317 | 743 | struct cfq_io_context *cic; |
da775265 | 744 | struct cfq_queue *cfqq; |
da775265 JA |
745 | |
746 | /* | |
ec8acb69 | 747 | * Disallow merge of a sync bio into an async request. |
da775265 | 748 | */ |
91fac317 | 749 | if (cfq_bio_sync(bio) && !rq_is_sync(rq)) |
da775265 JA |
750 | return 0; |
751 | ||
752 | /* | |
719d3402 JA |
753 | * Lookup the cfqq that this bio will be queued with. Allow |
754 | * merge only if rq is queued there. | |
da775265 | 755 | */ |
4ac845a2 | 756 | cic = cfq_cic_lookup(cfqd, current->io_context); |
91fac317 VT |
757 | if (!cic) |
758 | return 0; | |
719d3402 | 759 | |
91fac317 | 760 | cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); |
719d3402 JA |
761 | if (cfqq == RQ_CFQQ(rq)) |
762 | return 1; | |
da775265 | 763 | |
ec8acb69 | 764 | return 0; |
da775265 JA |
765 | } |
766 | ||
febffd61 JA |
767 | static void __cfq_set_active_queue(struct cfq_data *cfqd, |
768 | struct cfq_queue *cfqq) | |
22e2c507 JA |
769 | { |
770 | if (cfqq) { | |
7b679138 | 771 | cfq_log_cfqq(cfqd, cfqq, "set_active"); |
22e2c507 | 772 | cfqq->slice_end = 0; |
2f5cb738 JA |
773 | cfqq->slice_dispatch = 0; |
774 | ||
2f5cb738 | 775 | cfq_clear_cfqq_wait_request(cfqq); |
b029195d | 776 | cfq_clear_cfqq_must_dispatch(cfqq); |
3b18152c JA |
777 | cfq_clear_cfqq_must_alloc_slice(cfqq); |
778 | cfq_clear_cfqq_fifo_expire(cfqq); | |
44f7c160 | 779 | cfq_mark_cfqq_slice_new(cfqq); |
2f5cb738 JA |
780 | |
781 | del_timer(&cfqd->idle_slice_timer); | |
22e2c507 JA |
782 | } |
783 | ||
784 | cfqd->active_queue = cfqq; | |
785 | } | |
786 | ||
7b14e3b5 JA |
787 | /* |
788 | * current cfqq expired its slice (or was too idle), select new one | |
789 | */ | |
790 | static void | |
791 | __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
6084cdda | 792 | int timed_out) |
7b14e3b5 | 793 | { |
7b679138 JA |
794 | cfq_log_cfqq(cfqd, cfqq, "slice expired t=%d", timed_out); |
795 | ||
7b14e3b5 JA |
796 | if (cfq_cfqq_wait_request(cfqq)) |
797 | del_timer(&cfqd->idle_slice_timer); | |
798 | ||
7b14e3b5 JA |
799 | cfq_clear_cfqq_wait_request(cfqq); |
800 | ||
801 | /* | |
6084cdda | 802 | * store what was left of this slice, if the queue idled/timed out |
7b14e3b5 | 803 | */ |
7b679138 | 804 | if (timed_out && !cfq_cfqq_slice_new(cfqq)) { |
c5b680f3 | 805 | cfqq->slice_resid = cfqq->slice_end - jiffies; |
7b679138 JA |
806 | cfq_log_cfqq(cfqd, cfqq, "resid=%ld", cfqq->slice_resid); |
807 | } | |
7b14e3b5 | 808 | |
edd75ffd | 809 | cfq_resort_rr_list(cfqd, cfqq); |
7b14e3b5 JA |
810 | |
811 | if (cfqq == cfqd->active_queue) | |
812 | cfqd->active_queue = NULL; | |
813 | ||
814 | if (cfqd->active_cic) { | |
815 | put_io_context(cfqd->active_cic->ioc); | |
816 | cfqd->active_cic = NULL; | |
817 | } | |
7b14e3b5 JA |
818 | } |
819 | ||
6084cdda | 820 | static inline void cfq_slice_expired(struct cfq_data *cfqd, int timed_out) |
7b14e3b5 JA |
821 | { |
822 | struct cfq_queue *cfqq = cfqd->active_queue; | |
823 | ||
824 | if (cfqq) | |
6084cdda | 825 | __cfq_slice_expired(cfqd, cfqq, timed_out); |
7b14e3b5 JA |
826 | } |
827 | ||
498d3aa2 JA |
828 | /* |
829 | * Get next queue for service. Unless we have a queue preemption, | |
830 | * we'll simply select the first cfqq in the service tree. | |
831 | */ | |
6d048f53 | 832 | static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd) |
22e2c507 | 833 | { |
edd75ffd JA |
834 | if (RB_EMPTY_ROOT(&cfqd->service_tree.rb)) |
835 | return NULL; | |
d9e7620e | 836 | |
0871714e | 837 | return cfq_rb_first(&cfqd->service_tree); |
6d048f53 JA |
838 | } |
839 | ||
498d3aa2 JA |
840 | /* |
841 | * Get and set a new active queue for service. | |
842 | */ | |
6d048f53 JA |
843 | static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd) |
844 | { | |
845 | struct cfq_queue *cfqq; | |
846 | ||
d9e7620e | 847 | cfqq = cfq_get_next_queue(cfqd); |
22e2c507 | 848 | __cfq_set_active_queue(cfqd, cfqq); |
3b18152c | 849 | return cfqq; |
22e2c507 JA |
850 | } |
851 | ||
d9e7620e JA |
852 | static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd, |
853 | struct request *rq) | |
854 | { | |
855 | if (rq->sector >= cfqd->last_position) | |
856 | return rq->sector - cfqd->last_position; | |
857 | else | |
858 | return cfqd->last_position - rq->sector; | |
859 | } | |
860 | ||
6d048f53 JA |
861 | static inline int cfq_rq_close(struct cfq_data *cfqd, struct request *rq) |
862 | { | |
863 | struct cfq_io_context *cic = cfqd->active_cic; | |
864 | ||
865 | if (!sample_valid(cic->seek_samples)) | |
866 | return 0; | |
867 | ||
868 | return cfq_dist_from_last(cfqd, rq) <= cic->seek_mean; | |
869 | } | |
870 | ||
d9e7620e JA |
871 | static int cfq_close_cooperator(struct cfq_data *cfq_data, |
872 | struct cfq_queue *cfqq) | |
6d048f53 | 873 | { |
6d048f53 | 874 | /* |
d9e7620e JA |
875 | * We should notice if some of the queues are cooperating, eg |
876 | * working closely on the same area of the disk. In that case, | |
877 | * we can group them together and don't waste time idling. | |
6d048f53 | 878 | */ |
d9e7620e | 879 | return 0; |
6d048f53 JA |
880 | } |
881 | ||
882 | #define CIC_SEEKY(cic) ((cic)->seek_mean > (8 * 1024)) | |
caaa5f9f | 883 | |
6d048f53 | 884 | static void cfq_arm_slice_timer(struct cfq_data *cfqd) |
22e2c507 | 885 | { |
1792669c | 886 | struct cfq_queue *cfqq = cfqd->active_queue; |
206dc69b | 887 | struct cfq_io_context *cic; |
7b14e3b5 JA |
888 | unsigned long sl; |
889 | ||
a68bbddb | 890 | /* |
f7d7b7a7 JA |
891 | * SSD device without seek penalty, disable idling. But only do so |
892 | * for devices that support queuing, otherwise we still have a problem | |
893 | * with sync vs async workloads. | |
a68bbddb | 894 | */ |
f7d7b7a7 | 895 | if (blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag) |
a68bbddb JA |
896 | return; |
897 | ||
dd67d051 | 898 | WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list)); |
6d048f53 | 899 | WARN_ON(cfq_cfqq_slice_new(cfqq)); |
22e2c507 JA |
900 | |
901 | /* | |
902 | * idle is disabled, either manually or by past process history | |
903 | */ | |
6d048f53 JA |
904 | if (!cfqd->cfq_slice_idle || !cfq_cfqq_idle_window(cfqq)) |
905 | return; | |
906 | ||
7b679138 JA |
907 | /* |
908 | * still requests with the driver, don't idle | |
909 | */ | |
910 | if (cfqd->rq_in_driver) | |
911 | return; | |
912 | ||
22e2c507 JA |
913 | /* |
914 | * task has exited, don't wait | |
915 | */ | |
206dc69b | 916 | cic = cfqd->active_cic; |
66dac98e | 917 | if (!cic || !atomic_read(&cic->ioc->nr_tasks)) |
6d048f53 JA |
918 | return; |
919 | ||
920 | /* | |
921 | * See if this prio level has a good candidate | |
922 | */ | |
1afba045 JA |
923 | if (cfq_close_cooperator(cfqd, cfqq) && |
924 | (sample_valid(cic->ttime_samples) && cic->ttime_mean > 2)) | |
6d048f53 | 925 | return; |
22e2c507 | 926 | |
3b18152c | 927 | cfq_mark_cfqq_wait_request(cfqq); |
22e2c507 | 928 | |
206dc69b JA |
929 | /* |
930 | * we don't want to idle for seeks, but we do want to allow | |
931 | * fair distribution of slice time for a process doing back-to-back | |
932 | * seeks. so allow a little bit of time for him to submit a new rq | |
933 | */ | |
6d048f53 | 934 | sl = cfqd->cfq_slice_idle; |
caaa5f9f | 935 | if (sample_valid(cic->seek_samples) && CIC_SEEKY(cic)) |
d9e7620e | 936 | sl = min(sl, msecs_to_jiffies(CFQ_MIN_TT)); |
206dc69b | 937 | |
7b14e3b5 | 938 | mod_timer(&cfqd->idle_slice_timer, jiffies + sl); |
9481ffdc | 939 | cfq_log_cfqq(cfqd, cfqq, "arm_idle: %lu", sl); |
1da177e4 LT |
940 | } |
941 | ||
498d3aa2 JA |
942 | /* |
943 | * Move request from internal lists to the request queue dispatch list. | |
944 | */ | |
165125e1 | 945 | static void cfq_dispatch_insert(struct request_queue *q, struct request *rq) |
1da177e4 | 946 | { |
3ed9a296 | 947 | struct cfq_data *cfqd = q->elevator->elevator_data; |
5e705374 | 948 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 | 949 | |
7b679138 JA |
950 | cfq_log_cfqq(cfqd, cfqq, "dispatch_insert"); |
951 | ||
5380a101 | 952 | cfq_remove_request(rq); |
6d048f53 | 953 | cfqq->dispatched++; |
5380a101 | 954 | elv_dispatch_sort(q, rq); |
3ed9a296 JA |
955 | |
956 | if (cfq_cfqq_sync(cfqq)) | |
957 | cfqd->sync_flight++; | |
1da177e4 LT |
958 | } |
959 | ||
960 | /* | |
961 | * return expired entry, or NULL to just start from scratch in rbtree | |
962 | */ | |
febffd61 | 963 | static struct request *cfq_check_fifo(struct cfq_queue *cfqq) |
1da177e4 LT |
964 | { |
965 | struct cfq_data *cfqd = cfqq->cfqd; | |
22e2c507 | 966 | struct request *rq; |
89850f7e | 967 | int fifo; |
1da177e4 | 968 | |
3b18152c | 969 | if (cfq_cfqq_fifo_expire(cfqq)) |
1da177e4 | 970 | return NULL; |
cb887411 JA |
971 | |
972 | cfq_mark_cfqq_fifo_expire(cfqq); | |
973 | ||
89850f7e JA |
974 | if (list_empty(&cfqq->fifo)) |
975 | return NULL; | |
1da177e4 | 976 | |
6d048f53 | 977 | fifo = cfq_cfqq_sync(cfqq); |
89850f7e | 978 | rq = rq_entry_fifo(cfqq->fifo.next); |
1da177e4 | 979 | |
6d048f53 | 980 | if (time_before(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) |
7b679138 | 981 | rq = NULL; |
1da177e4 | 982 | |
7b679138 | 983 | cfq_log_cfqq(cfqd, cfqq, "fifo=%p", rq); |
6d048f53 | 984 | return rq; |
1da177e4 LT |
985 | } |
986 | ||
22e2c507 JA |
987 | static inline int |
988 | cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
989 | { | |
990 | const int base_rq = cfqd->cfq_slice_async_rq; | |
1da177e4 | 991 | |
22e2c507 | 992 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); |
1da177e4 | 993 | |
22e2c507 | 994 | return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio)); |
1da177e4 LT |
995 | } |
996 | ||
22e2c507 | 997 | /* |
498d3aa2 JA |
998 | * Select a queue for service. If we have a current active queue, |
999 | * check whether to continue servicing it, or retrieve and set a new one. | |
22e2c507 | 1000 | */ |
1b5ed5e1 | 1001 | static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) |
1da177e4 | 1002 | { |
1da177e4 | 1003 | struct cfq_queue *cfqq; |
1da177e4 | 1004 | |
22e2c507 JA |
1005 | cfqq = cfqd->active_queue; |
1006 | if (!cfqq) | |
1007 | goto new_queue; | |
1da177e4 | 1008 | |
22e2c507 | 1009 | /* |
6d048f53 | 1010 | * The active queue has run out of time, expire it and select new. |
22e2c507 | 1011 | */ |
b029195d | 1012 | if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq)) |
3b18152c | 1013 | goto expire; |
1da177e4 | 1014 | |
3a9a3f6c DS |
1015 | /* |
1016 | * If we have a RT cfqq waiting, then we pre-empt the current non-rt | |
1017 | * cfqq. | |
1018 | */ | |
1019 | if (!cfq_class_rt(cfqq) && cfqd->busy_rt_queues) { | |
1020 | /* | |
1021 | * We simulate this as cfqq timed out so that it gets to bank | |
1022 | * the remaining of its time slice. | |
1023 | */ | |
1024 | cfq_log_cfqq(cfqd, cfqq, "preempt"); | |
1025 | cfq_slice_expired(cfqd, 1); | |
1026 | goto new_queue; | |
1027 | } | |
1028 | ||
22e2c507 | 1029 | /* |
6d048f53 JA |
1030 | * The active queue has requests and isn't expired, allow it to |
1031 | * dispatch. | |
22e2c507 | 1032 | */ |
dd67d051 | 1033 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
22e2c507 | 1034 | goto keep_queue; |
6d048f53 JA |
1035 | |
1036 | /* | |
1037 | * No requests pending. If the active queue still has requests in | |
1038 | * flight or is idling for a new request, allow either of these | |
1039 | * conditions to happen (or time out) before selecting a new queue. | |
1040 | */ | |
cc197479 JA |
1041 | if (timer_pending(&cfqd->idle_slice_timer) || |
1042 | (cfqq->dispatched && cfq_cfqq_idle_window(cfqq))) { | |
caaa5f9f JA |
1043 | cfqq = NULL; |
1044 | goto keep_queue; | |
22e2c507 JA |
1045 | } |
1046 | ||
3b18152c | 1047 | expire: |
6084cdda | 1048 | cfq_slice_expired(cfqd, 0); |
3b18152c JA |
1049 | new_queue: |
1050 | cfqq = cfq_set_active_queue(cfqd); | |
22e2c507 | 1051 | keep_queue: |
3b18152c | 1052 | return cfqq; |
22e2c507 JA |
1053 | } |
1054 | ||
febffd61 | 1055 | static int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq) |
d9e7620e JA |
1056 | { |
1057 | int dispatched = 0; | |
1058 | ||
1059 | while (cfqq->next_rq) { | |
1060 | cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq); | |
1061 | dispatched++; | |
1062 | } | |
1063 | ||
1064 | BUG_ON(!list_empty(&cfqq->fifo)); | |
1065 | return dispatched; | |
1066 | } | |
1067 | ||
498d3aa2 JA |
1068 | /* |
1069 | * Drain our current requests. Used for barriers and when switching | |
1070 | * io schedulers on-the-fly. | |
1071 | */ | |
d9e7620e | 1072 | static int cfq_forced_dispatch(struct cfq_data *cfqd) |
1b5ed5e1 | 1073 | { |
0871714e | 1074 | struct cfq_queue *cfqq; |
d9e7620e | 1075 | int dispatched = 0; |
1b5ed5e1 | 1076 | |
0871714e | 1077 | while ((cfqq = cfq_rb_first(&cfqd->service_tree)) != NULL) |
d9e7620e | 1078 | dispatched += __cfq_forced_dispatch_cfqq(cfqq); |
1b5ed5e1 | 1079 | |
6084cdda | 1080 | cfq_slice_expired(cfqd, 0); |
1b5ed5e1 TH |
1081 | |
1082 | BUG_ON(cfqd->busy_queues); | |
1083 | ||
7b679138 | 1084 | cfq_log(cfqd, "forced_dispatch=%d\n", dispatched); |
1b5ed5e1 TH |
1085 | return dispatched; |
1086 | } | |
1087 | ||
2f5cb738 JA |
1088 | /* |
1089 | * Dispatch a request from cfqq, moving them to the request queue | |
1090 | * dispatch list. | |
1091 | */ | |
1092 | static void cfq_dispatch_request(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1093 | { | |
1094 | struct request *rq; | |
1095 | ||
1096 | BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list)); | |
1097 | ||
1098 | /* | |
1099 | * follow expired path, else get first next available | |
1100 | */ | |
1101 | rq = cfq_check_fifo(cfqq); | |
1102 | if (!rq) | |
1103 | rq = cfqq->next_rq; | |
1104 | ||
1105 | /* | |
1106 | * insert request into driver dispatch list | |
1107 | */ | |
1108 | cfq_dispatch_insert(cfqd->queue, rq); | |
1109 | ||
1110 | if (!cfqd->active_cic) { | |
1111 | struct cfq_io_context *cic = RQ_CIC(rq); | |
1112 | ||
1113 | atomic_inc(&cic->ioc->refcount); | |
1114 | cfqd->active_cic = cic; | |
1115 | } | |
1116 | } | |
1117 | ||
1118 | /* | |
1119 | * Find the cfqq that we need to service and move a request from that to the | |
1120 | * dispatch list | |
1121 | */ | |
165125e1 | 1122 | static int cfq_dispatch_requests(struct request_queue *q, int force) |
22e2c507 JA |
1123 | { |
1124 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
6d048f53 | 1125 | struct cfq_queue *cfqq; |
2f5cb738 | 1126 | unsigned int max_dispatch; |
22e2c507 JA |
1127 | |
1128 | if (!cfqd->busy_queues) | |
1129 | return 0; | |
1130 | ||
1b5ed5e1 TH |
1131 | if (unlikely(force)) |
1132 | return cfq_forced_dispatch(cfqd); | |
1133 | ||
2f5cb738 JA |
1134 | cfqq = cfq_select_queue(cfqd); |
1135 | if (!cfqq) | |
1136 | return 0; | |
1137 | ||
1138 | /* | |
1139 | * If this is an async queue and we have sync IO in flight, let it wait | |
1140 | */ | |
1141 | if (cfqd->sync_flight && !cfq_cfqq_sync(cfqq)) | |
1142 | return 0; | |
1143 | ||
1144 | max_dispatch = cfqd->cfq_quantum; | |
1145 | if (cfq_class_idle(cfqq)) | |
1146 | max_dispatch = 1; | |
b4878f24 | 1147 | |
2f5cb738 JA |
1148 | /* |
1149 | * Does this cfqq already have too much IO in flight? | |
1150 | */ | |
1151 | if (cfqq->dispatched >= max_dispatch) { | |
1152 | /* | |
1153 | * idle queue must always only have a single IO in flight | |
1154 | */ | |
3ed9a296 | 1155 | if (cfq_class_idle(cfqq)) |
2f5cb738 | 1156 | return 0; |
3ed9a296 | 1157 | |
2f5cb738 JA |
1158 | /* |
1159 | * We have other queues, don't allow more IO from this one | |
1160 | */ | |
1161 | if (cfqd->busy_queues > 1) | |
1162 | return 0; | |
9ede209e | 1163 | |
2f5cb738 JA |
1164 | /* |
1165 | * we are the only queue, allow up to 4 times of 'quantum' | |
1166 | */ | |
1167 | if (cfqq->dispatched >= 4 * max_dispatch) | |
1168 | return 0; | |
1169 | } | |
3ed9a296 | 1170 | |
2f5cb738 JA |
1171 | /* |
1172 | * Dispatch a request from this cfqq | |
1173 | */ | |
1174 | cfq_dispatch_request(cfqd, cfqq); | |
1175 | cfqq->slice_dispatch++; | |
b029195d | 1176 | cfq_clear_cfqq_must_dispatch(cfqq); |
22e2c507 | 1177 | |
2f5cb738 JA |
1178 | /* |
1179 | * expire an async queue immediately if it has used up its slice. idle | |
1180 | * queue always expire after 1 dispatch round. | |
1181 | */ | |
1182 | if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) && | |
1183 | cfqq->slice_dispatch >= cfq_prio_to_maxrq(cfqd, cfqq)) || | |
1184 | cfq_class_idle(cfqq))) { | |
1185 | cfqq->slice_end = jiffies + 1; | |
1186 | cfq_slice_expired(cfqd, 0); | |
1da177e4 LT |
1187 | } |
1188 | ||
2f5cb738 JA |
1189 | cfq_log(cfqd, "dispatched a request"); |
1190 | return 1; | |
1da177e4 LT |
1191 | } |
1192 | ||
1da177e4 | 1193 | /* |
5e705374 JA |
1194 | * task holds one reference to the queue, dropped when task exits. each rq |
1195 | * in-flight on this queue also holds a reference, dropped when rq is freed. | |
1da177e4 LT |
1196 | * |
1197 | * queue lock must be held here. | |
1198 | */ | |
1199 | static void cfq_put_queue(struct cfq_queue *cfqq) | |
1200 | { | |
22e2c507 JA |
1201 | struct cfq_data *cfqd = cfqq->cfqd; |
1202 | ||
1203 | BUG_ON(atomic_read(&cfqq->ref) <= 0); | |
1da177e4 LT |
1204 | |
1205 | if (!atomic_dec_and_test(&cfqq->ref)) | |
1206 | return; | |
1207 | ||
7b679138 | 1208 | cfq_log_cfqq(cfqd, cfqq, "put_queue"); |
1da177e4 | 1209 | BUG_ON(rb_first(&cfqq->sort_list)); |
22e2c507 | 1210 | BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]); |
3b18152c | 1211 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
1da177e4 | 1212 | |
28f95cbc | 1213 | if (unlikely(cfqd->active_queue == cfqq)) { |
6084cdda | 1214 | __cfq_slice_expired(cfqd, cfqq, 0); |
28f95cbc JA |
1215 | cfq_schedule_dispatch(cfqd); |
1216 | } | |
22e2c507 | 1217 | |
1da177e4 LT |
1218 | kmem_cache_free(cfq_pool, cfqq); |
1219 | } | |
1220 | ||
d6de8be7 JA |
1221 | /* |
1222 | * Must always be called with the rcu_read_lock() held | |
1223 | */ | |
07416d29 JA |
1224 | static void |
1225 | __call_for_each_cic(struct io_context *ioc, | |
1226 | void (*func)(struct io_context *, struct cfq_io_context *)) | |
1227 | { | |
1228 | struct cfq_io_context *cic; | |
1229 | struct hlist_node *n; | |
1230 | ||
1231 | hlist_for_each_entry_rcu(cic, n, &ioc->cic_list, cic_list) | |
1232 | func(ioc, cic); | |
1233 | } | |
1234 | ||
4ac845a2 | 1235 | /* |
34e6bbf2 | 1236 | * Call func for each cic attached to this ioc. |
4ac845a2 | 1237 | */ |
34e6bbf2 | 1238 | static void |
4ac845a2 JA |
1239 | call_for_each_cic(struct io_context *ioc, |
1240 | void (*func)(struct io_context *, struct cfq_io_context *)) | |
1da177e4 | 1241 | { |
4ac845a2 | 1242 | rcu_read_lock(); |
07416d29 | 1243 | __call_for_each_cic(ioc, func); |
4ac845a2 | 1244 | rcu_read_unlock(); |
34e6bbf2 FC |
1245 | } |
1246 | ||
1247 | static void cfq_cic_free_rcu(struct rcu_head *head) | |
1248 | { | |
1249 | struct cfq_io_context *cic; | |
1250 | ||
1251 | cic = container_of(head, struct cfq_io_context, rcu_head); | |
1252 | ||
1253 | kmem_cache_free(cfq_ioc_pool, cic); | |
1254 | elv_ioc_count_dec(ioc_count); | |
1255 | ||
9a11b4ed JA |
1256 | if (ioc_gone) { |
1257 | /* | |
1258 | * CFQ scheduler is exiting, grab exit lock and check | |
1259 | * the pending io context count. If it hits zero, | |
1260 | * complete ioc_gone and set it back to NULL | |
1261 | */ | |
1262 | spin_lock(&ioc_gone_lock); | |
1263 | if (ioc_gone && !elv_ioc_count_read(ioc_count)) { | |
1264 | complete(ioc_gone); | |
1265 | ioc_gone = NULL; | |
1266 | } | |
1267 | spin_unlock(&ioc_gone_lock); | |
1268 | } | |
34e6bbf2 | 1269 | } |
4ac845a2 | 1270 | |
34e6bbf2 FC |
1271 | static void cfq_cic_free(struct cfq_io_context *cic) |
1272 | { | |
1273 | call_rcu(&cic->rcu_head, cfq_cic_free_rcu); | |
4ac845a2 JA |
1274 | } |
1275 | ||
1276 | static void cic_free_func(struct io_context *ioc, struct cfq_io_context *cic) | |
1277 | { | |
1278 | unsigned long flags; | |
1279 | ||
1280 | BUG_ON(!cic->dead_key); | |
1281 | ||
1282 | spin_lock_irqsave(&ioc->lock, flags); | |
1283 | radix_tree_delete(&ioc->radix_root, cic->dead_key); | |
ffc4e759 | 1284 | hlist_del_rcu(&cic->cic_list); |
4ac845a2 JA |
1285 | spin_unlock_irqrestore(&ioc->lock, flags); |
1286 | ||
34e6bbf2 | 1287 | cfq_cic_free(cic); |
4ac845a2 JA |
1288 | } |
1289 | ||
d6de8be7 JA |
1290 | /* |
1291 | * Must be called with rcu_read_lock() held or preemption otherwise disabled. | |
1292 | * Only two callers of this - ->dtor() which is called with the rcu_read_lock(), | |
1293 | * and ->trim() which is called with the task lock held | |
1294 | */ | |
4ac845a2 JA |
1295 | static void cfq_free_io_context(struct io_context *ioc) |
1296 | { | |
4ac845a2 | 1297 | /* |
34e6bbf2 FC |
1298 | * ioc->refcount is zero here, or we are called from elv_unregister(), |
1299 | * so no more cic's are allowed to be linked into this ioc. So it | |
1300 | * should be ok to iterate over the known list, we will see all cic's | |
1301 | * since no new ones are added. | |
4ac845a2 | 1302 | */ |
07416d29 | 1303 | __call_for_each_cic(ioc, cic_free_func); |
1da177e4 LT |
1304 | } |
1305 | ||
89850f7e | 1306 | static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 1307 | { |
28f95cbc | 1308 | if (unlikely(cfqq == cfqd->active_queue)) { |
6084cdda | 1309 | __cfq_slice_expired(cfqd, cfqq, 0); |
28f95cbc JA |
1310 | cfq_schedule_dispatch(cfqd); |
1311 | } | |
22e2c507 | 1312 | |
89850f7e JA |
1313 | cfq_put_queue(cfqq); |
1314 | } | |
22e2c507 | 1315 | |
89850f7e JA |
1316 | static void __cfq_exit_single_io_context(struct cfq_data *cfqd, |
1317 | struct cfq_io_context *cic) | |
1318 | { | |
4faa3c81 FC |
1319 | struct io_context *ioc = cic->ioc; |
1320 | ||
fc46379d | 1321 | list_del_init(&cic->queue_list); |
4ac845a2 JA |
1322 | |
1323 | /* | |
1324 | * Make sure key == NULL is seen for dead queues | |
1325 | */ | |
fc46379d | 1326 | smp_wmb(); |
4ac845a2 | 1327 | cic->dead_key = (unsigned long) cic->key; |
fc46379d JA |
1328 | cic->key = NULL; |
1329 | ||
4faa3c81 FC |
1330 | if (ioc->ioc_data == cic) |
1331 | rcu_assign_pointer(ioc->ioc_data, NULL); | |
1332 | ||
ff6657c6 JA |
1333 | if (cic->cfqq[BLK_RW_ASYNC]) { |
1334 | cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_ASYNC]); | |
1335 | cic->cfqq[BLK_RW_ASYNC] = NULL; | |
12a05732 AV |
1336 | } |
1337 | ||
ff6657c6 JA |
1338 | if (cic->cfqq[BLK_RW_SYNC]) { |
1339 | cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_SYNC]); | |
1340 | cic->cfqq[BLK_RW_SYNC] = NULL; | |
12a05732 | 1341 | } |
89850f7e JA |
1342 | } |
1343 | ||
4ac845a2 JA |
1344 | static void cfq_exit_single_io_context(struct io_context *ioc, |
1345 | struct cfq_io_context *cic) | |
89850f7e JA |
1346 | { |
1347 | struct cfq_data *cfqd = cic->key; | |
1348 | ||
89850f7e | 1349 | if (cfqd) { |
165125e1 | 1350 | struct request_queue *q = cfqd->queue; |
4ac845a2 | 1351 | unsigned long flags; |
89850f7e | 1352 | |
4ac845a2 | 1353 | spin_lock_irqsave(q->queue_lock, flags); |
62c1fe9d JA |
1354 | |
1355 | /* | |
1356 | * Ensure we get a fresh copy of the ->key to prevent | |
1357 | * race between exiting task and queue | |
1358 | */ | |
1359 | smp_read_barrier_depends(); | |
1360 | if (cic->key) | |
1361 | __cfq_exit_single_io_context(cfqd, cic); | |
1362 | ||
4ac845a2 | 1363 | spin_unlock_irqrestore(q->queue_lock, flags); |
89850f7e | 1364 | } |
1da177e4 LT |
1365 | } |
1366 | ||
498d3aa2 JA |
1367 | /* |
1368 | * The process that ioc belongs to has exited, we need to clean up | |
1369 | * and put the internal structures we have that belongs to that process. | |
1370 | */ | |
e2d74ac0 | 1371 | static void cfq_exit_io_context(struct io_context *ioc) |
1da177e4 | 1372 | { |
4ac845a2 | 1373 | call_for_each_cic(ioc, cfq_exit_single_io_context); |
1da177e4 LT |
1374 | } |
1375 | ||
22e2c507 | 1376 | static struct cfq_io_context * |
8267e268 | 1377 | cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
1da177e4 | 1378 | { |
b5deef90 | 1379 | struct cfq_io_context *cic; |
1da177e4 | 1380 | |
94f6030c CL |
1381 | cic = kmem_cache_alloc_node(cfq_ioc_pool, gfp_mask | __GFP_ZERO, |
1382 | cfqd->queue->node); | |
1da177e4 | 1383 | if (cic) { |
22e2c507 | 1384 | cic->last_end_request = jiffies; |
553698f9 | 1385 | INIT_LIST_HEAD(&cic->queue_list); |
ffc4e759 | 1386 | INIT_HLIST_NODE(&cic->cic_list); |
22e2c507 JA |
1387 | cic->dtor = cfq_free_io_context; |
1388 | cic->exit = cfq_exit_io_context; | |
4050cf16 | 1389 | elv_ioc_count_inc(ioc_count); |
1da177e4 LT |
1390 | } |
1391 | ||
1392 | return cic; | |
1393 | } | |
1394 | ||
fd0928df | 1395 | static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc) |
22e2c507 JA |
1396 | { |
1397 | struct task_struct *tsk = current; | |
1398 | int ioprio_class; | |
1399 | ||
3b18152c | 1400 | if (!cfq_cfqq_prio_changed(cfqq)) |
22e2c507 JA |
1401 | return; |
1402 | ||
fd0928df | 1403 | ioprio_class = IOPRIO_PRIO_CLASS(ioc->ioprio); |
22e2c507 | 1404 | switch (ioprio_class) { |
fe094d98 JA |
1405 | default: |
1406 | printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class); | |
1407 | case IOPRIO_CLASS_NONE: | |
1408 | /* | |
6d63c275 | 1409 | * no prio set, inherit CPU scheduling settings |
fe094d98 JA |
1410 | */ |
1411 | cfqq->ioprio = task_nice_ioprio(tsk); | |
6d63c275 | 1412 | cfqq->ioprio_class = task_nice_ioclass(tsk); |
fe094d98 JA |
1413 | break; |
1414 | case IOPRIO_CLASS_RT: | |
1415 | cfqq->ioprio = task_ioprio(ioc); | |
1416 | cfqq->ioprio_class = IOPRIO_CLASS_RT; | |
1417 | break; | |
1418 | case IOPRIO_CLASS_BE: | |
1419 | cfqq->ioprio = task_ioprio(ioc); | |
1420 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
1421 | break; | |
1422 | case IOPRIO_CLASS_IDLE: | |
1423 | cfqq->ioprio_class = IOPRIO_CLASS_IDLE; | |
1424 | cfqq->ioprio = 7; | |
1425 | cfq_clear_cfqq_idle_window(cfqq); | |
1426 | break; | |
22e2c507 JA |
1427 | } |
1428 | ||
1429 | /* | |
1430 | * keep track of original prio settings in case we have to temporarily | |
1431 | * elevate the priority of this queue | |
1432 | */ | |
1433 | cfqq->org_ioprio = cfqq->ioprio; | |
1434 | cfqq->org_ioprio_class = cfqq->ioprio_class; | |
3b18152c | 1435 | cfq_clear_cfqq_prio_changed(cfqq); |
22e2c507 JA |
1436 | } |
1437 | ||
febffd61 | 1438 | static void changed_ioprio(struct io_context *ioc, struct cfq_io_context *cic) |
22e2c507 | 1439 | { |
478a82b0 AV |
1440 | struct cfq_data *cfqd = cic->key; |
1441 | struct cfq_queue *cfqq; | |
c1b707d2 | 1442 | unsigned long flags; |
35e6077c | 1443 | |
caaa5f9f JA |
1444 | if (unlikely(!cfqd)) |
1445 | return; | |
1446 | ||
c1b707d2 | 1447 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); |
caaa5f9f | 1448 | |
ff6657c6 | 1449 | cfqq = cic->cfqq[BLK_RW_ASYNC]; |
caaa5f9f JA |
1450 | if (cfqq) { |
1451 | struct cfq_queue *new_cfqq; | |
ff6657c6 JA |
1452 | new_cfqq = cfq_get_queue(cfqd, BLK_RW_ASYNC, cic->ioc, |
1453 | GFP_ATOMIC); | |
caaa5f9f | 1454 | if (new_cfqq) { |
ff6657c6 | 1455 | cic->cfqq[BLK_RW_ASYNC] = new_cfqq; |
caaa5f9f JA |
1456 | cfq_put_queue(cfqq); |
1457 | } | |
22e2c507 | 1458 | } |
caaa5f9f | 1459 | |
ff6657c6 | 1460 | cfqq = cic->cfqq[BLK_RW_SYNC]; |
caaa5f9f JA |
1461 | if (cfqq) |
1462 | cfq_mark_cfqq_prio_changed(cfqq); | |
1463 | ||
c1b707d2 | 1464 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); |
22e2c507 JA |
1465 | } |
1466 | ||
fc46379d | 1467 | static void cfq_ioc_set_ioprio(struct io_context *ioc) |
22e2c507 | 1468 | { |
4ac845a2 | 1469 | call_for_each_cic(ioc, changed_ioprio); |
fc46379d | 1470 | ioc->ioprio_changed = 0; |
22e2c507 JA |
1471 | } |
1472 | ||
1473 | static struct cfq_queue * | |
15c31be4 | 1474 | cfq_find_alloc_queue(struct cfq_data *cfqd, int is_sync, |
fd0928df | 1475 | struct io_context *ioc, gfp_t gfp_mask) |
22e2c507 | 1476 | { |
22e2c507 | 1477 | struct cfq_queue *cfqq, *new_cfqq = NULL; |
91fac317 | 1478 | struct cfq_io_context *cic; |
22e2c507 JA |
1479 | |
1480 | retry: | |
4ac845a2 | 1481 | cic = cfq_cic_lookup(cfqd, ioc); |
91fac317 VT |
1482 | /* cic always exists here */ |
1483 | cfqq = cic_to_cfqq(cic, is_sync); | |
22e2c507 JA |
1484 | |
1485 | if (!cfqq) { | |
1486 | if (new_cfqq) { | |
1487 | cfqq = new_cfqq; | |
1488 | new_cfqq = NULL; | |
1489 | } else if (gfp_mask & __GFP_WAIT) { | |
89850f7e JA |
1490 | /* |
1491 | * Inform the allocator of the fact that we will | |
1492 | * just repeat this allocation if it fails, to allow | |
1493 | * the allocator to do whatever it needs to attempt to | |
1494 | * free memory. | |
1495 | */ | |
22e2c507 | 1496 | spin_unlock_irq(cfqd->queue->queue_lock); |
94f6030c CL |
1497 | new_cfqq = kmem_cache_alloc_node(cfq_pool, |
1498 | gfp_mask | __GFP_NOFAIL | __GFP_ZERO, | |
1499 | cfqd->queue->node); | |
22e2c507 JA |
1500 | spin_lock_irq(cfqd->queue->queue_lock); |
1501 | goto retry; | |
1502 | } else { | |
94f6030c CL |
1503 | cfqq = kmem_cache_alloc_node(cfq_pool, |
1504 | gfp_mask | __GFP_ZERO, | |
1505 | cfqd->queue->node); | |
22e2c507 JA |
1506 | if (!cfqq) |
1507 | goto out; | |
1508 | } | |
1509 | ||
d9e7620e | 1510 | RB_CLEAR_NODE(&cfqq->rb_node); |
22e2c507 JA |
1511 | INIT_LIST_HEAD(&cfqq->fifo); |
1512 | ||
22e2c507 JA |
1513 | atomic_set(&cfqq->ref, 0); |
1514 | cfqq->cfqd = cfqd; | |
c5b680f3 | 1515 | |
3b18152c | 1516 | cfq_mark_cfqq_prio_changed(cfqq); |
91fac317 | 1517 | |
fd0928df | 1518 | cfq_init_prio_data(cfqq, ioc); |
0871714e JA |
1519 | |
1520 | if (is_sync) { | |
1521 | if (!cfq_class_idle(cfqq)) | |
1522 | cfq_mark_cfqq_idle_window(cfqq); | |
1523 | cfq_mark_cfqq_sync(cfqq); | |
1524 | } | |
7b679138 JA |
1525 | cfqq->pid = current->pid; |
1526 | cfq_log_cfqq(cfqd, cfqq, "alloced"); | |
22e2c507 JA |
1527 | } |
1528 | ||
1529 | if (new_cfqq) | |
1530 | kmem_cache_free(cfq_pool, new_cfqq); | |
1531 | ||
22e2c507 JA |
1532 | out: |
1533 | WARN_ON((gfp_mask & __GFP_WAIT) && !cfqq); | |
1534 | return cfqq; | |
1535 | } | |
1536 | ||
c2dea2d1 VT |
1537 | static struct cfq_queue ** |
1538 | cfq_async_queue_prio(struct cfq_data *cfqd, int ioprio_class, int ioprio) | |
1539 | { | |
fe094d98 | 1540 | switch (ioprio_class) { |
c2dea2d1 VT |
1541 | case IOPRIO_CLASS_RT: |
1542 | return &cfqd->async_cfqq[0][ioprio]; | |
1543 | case IOPRIO_CLASS_BE: | |
1544 | return &cfqd->async_cfqq[1][ioprio]; | |
1545 | case IOPRIO_CLASS_IDLE: | |
1546 | return &cfqd->async_idle_cfqq; | |
1547 | default: | |
1548 | BUG(); | |
1549 | } | |
1550 | } | |
1551 | ||
15c31be4 | 1552 | static struct cfq_queue * |
fd0928df | 1553 | cfq_get_queue(struct cfq_data *cfqd, int is_sync, struct io_context *ioc, |
15c31be4 JA |
1554 | gfp_t gfp_mask) |
1555 | { | |
fd0928df JA |
1556 | const int ioprio = task_ioprio(ioc); |
1557 | const int ioprio_class = task_ioprio_class(ioc); | |
c2dea2d1 | 1558 | struct cfq_queue **async_cfqq = NULL; |
15c31be4 JA |
1559 | struct cfq_queue *cfqq = NULL; |
1560 | ||
c2dea2d1 VT |
1561 | if (!is_sync) { |
1562 | async_cfqq = cfq_async_queue_prio(cfqd, ioprio_class, ioprio); | |
1563 | cfqq = *async_cfqq; | |
1564 | } | |
1565 | ||
0a0836a0 | 1566 | if (!cfqq) { |
fd0928df | 1567 | cfqq = cfq_find_alloc_queue(cfqd, is_sync, ioc, gfp_mask); |
0a0836a0 ON |
1568 | if (!cfqq) |
1569 | return NULL; | |
1570 | } | |
15c31be4 JA |
1571 | |
1572 | /* | |
1573 | * pin the queue now that it's allocated, scheduler exit will prune it | |
1574 | */ | |
c2dea2d1 | 1575 | if (!is_sync && !(*async_cfqq)) { |
15c31be4 | 1576 | atomic_inc(&cfqq->ref); |
c2dea2d1 | 1577 | *async_cfqq = cfqq; |
15c31be4 JA |
1578 | } |
1579 | ||
1580 | atomic_inc(&cfqq->ref); | |
1581 | return cfqq; | |
1582 | } | |
1583 | ||
498d3aa2 JA |
1584 | /* |
1585 | * We drop cfq io contexts lazily, so we may find a dead one. | |
1586 | */ | |
dbecf3ab | 1587 | static void |
4ac845a2 JA |
1588 | cfq_drop_dead_cic(struct cfq_data *cfqd, struct io_context *ioc, |
1589 | struct cfq_io_context *cic) | |
dbecf3ab | 1590 | { |
4ac845a2 JA |
1591 | unsigned long flags; |
1592 | ||
fc46379d | 1593 | WARN_ON(!list_empty(&cic->queue_list)); |
597bc485 | 1594 | |
4ac845a2 JA |
1595 | spin_lock_irqsave(&ioc->lock, flags); |
1596 | ||
4faa3c81 | 1597 | BUG_ON(ioc->ioc_data == cic); |
597bc485 | 1598 | |
4ac845a2 | 1599 | radix_tree_delete(&ioc->radix_root, (unsigned long) cfqd); |
ffc4e759 | 1600 | hlist_del_rcu(&cic->cic_list); |
4ac845a2 JA |
1601 | spin_unlock_irqrestore(&ioc->lock, flags); |
1602 | ||
1603 | cfq_cic_free(cic); | |
dbecf3ab OH |
1604 | } |
1605 | ||
e2d74ac0 | 1606 | static struct cfq_io_context * |
4ac845a2 | 1607 | cfq_cic_lookup(struct cfq_data *cfqd, struct io_context *ioc) |
e2d74ac0 | 1608 | { |
e2d74ac0 | 1609 | struct cfq_io_context *cic; |
d6de8be7 | 1610 | unsigned long flags; |
4ac845a2 | 1611 | void *k; |
e2d74ac0 | 1612 | |
91fac317 VT |
1613 | if (unlikely(!ioc)) |
1614 | return NULL; | |
1615 | ||
d6de8be7 JA |
1616 | rcu_read_lock(); |
1617 | ||
597bc485 JA |
1618 | /* |
1619 | * we maintain a last-hit cache, to avoid browsing over the tree | |
1620 | */ | |
4ac845a2 | 1621 | cic = rcu_dereference(ioc->ioc_data); |
d6de8be7 JA |
1622 | if (cic && cic->key == cfqd) { |
1623 | rcu_read_unlock(); | |
597bc485 | 1624 | return cic; |
d6de8be7 | 1625 | } |
597bc485 | 1626 | |
4ac845a2 | 1627 | do { |
4ac845a2 JA |
1628 | cic = radix_tree_lookup(&ioc->radix_root, (unsigned long) cfqd); |
1629 | rcu_read_unlock(); | |
1630 | if (!cic) | |
1631 | break; | |
be3b0753 OH |
1632 | /* ->key must be copied to avoid race with cfq_exit_queue() */ |
1633 | k = cic->key; | |
1634 | if (unlikely(!k)) { | |
4ac845a2 | 1635 | cfq_drop_dead_cic(cfqd, ioc, cic); |
d6de8be7 | 1636 | rcu_read_lock(); |
4ac845a2 | 1637 | continue; |
dbecf3ab | 1638 | } |
e2d74ac0 | 1639 | |
d6de8be7 | 1640 | spin_lock_irqsave(&ioc->lock, flags); |
4ac845a2 | 1641 | rcu_assign_pointer(ioc->ioc_data, cic); |
d6de8be7 | 1642 | spin_unlock_irqrestore(&ioc->lock, flags); |
4ac845a2 JA |
1643 | break; |
1644 | } while (1); | |
e2d74ac0 | 1645 | |
4ac845a2 | 1646 | return cic; |
e2d74ac0 JA |
1647 | } |
1648 | ||
4ac845a2 JA |
1649 | /* |
1650 | * Add cic into ioc, using cfqd as the search key. This enables us to lookup | |
1651 | * the process specific cfq io context when entered from the block layer. | |
1652 | * Also adds the cic to a per-cfqd list, used when this queue is removed. | |
1653 | */ | |
febffd61 JA |
1654 | static int cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc, |
1655 | struct cfq_io_context *cic, gfp_t gfp_mask) | |
e2d74ac0 | 1656 | { |
0261d688 | 1657 | unsigned long flags; |
4ac845a2 | 1658 | int ret; |
e2d74ac0 | 1659 | |
4ac845a2 JA |
1660 | ret = radix_tree_preload(gfp_mask); |
1661 | if (!ret) { | |
1662 | cic->ioc = ioc; | |
1663 | cic->key = cfqd; | |
e2d74ac0 | 1664 | |
4ac845a2 JA |
1665 | spin_lock_irqsave(&ioc->lock, flags); |
1666 | ret = radix_tree_insert(&ioc->radix_root, | |
1667 | (unsigned long) cfqd, cic); | |
ffc4e759 JA |
1668 | if (!ret) |
1669 | hlist_add_head_rcu(&cic->cic_list, &ioc->cic_list); | |
4ac845a2 | 1670 | spin_unlock_irqrestore(&ioc->lock, flags); |
e2d74ac0 | 1671 | |
4ac845a2 JA |
1672 | radix_tree_preload_end(); |
1673 | ||
1674 | if (!ret) { | |
1675 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
1676 | list_add(&cic->queue_list, &cfqd->cic_list); | |
1677 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
1678 | } | |
e2d74ac0 JA |
1679 | } |
1680 | ||
4ac845a2 JA |
1681 | if (ret) |
1682 | printk(KERN_ERR "cfq: cic link failed!\n"); | |
fc46379d | 1683 | |
4ac845a2 | 1684 | return ret; |
e2d74ac0 JA |
1685 | } |
1686 | ||
1da177e4 LT |
1687 | /* |
1688 | * Setup general io context and cfq io context. There can be several cfq | |
1689 | * io contexts per general io context, if this process is doing io to more | |
e2d74ac0 | 1690 | * than one device managed by cfq. |
1da177e4 LT |
1691 | */ |
1692 | static struct cfq_io_context * | |
e2d74ac0 | 1693 | cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
1da177e4 | 1694 | { |
22e2c507 | 1695 | struct io_context *ioc = NULL; |
1da177e4 | 1696 | struct cfq_io_context *cic; |
1da177e4 | 1697 | |
22e2c507 | 1698 | might_sleep_if(gfp_mask & __GFP_WAIT); |
1da177e4 | 1699 | |
b5deef90 | 1700 | ioc = get_io_context(gfp_mask, cfqd->queue->node); |
1da177e4 LT |
1701 | if (!ioc) |
1702 | return NULL; | |
1703 | ||
4ac845a2 | 1704 | cic = cfq_cic_lookup(cfqd, ioc); |
e2d74ac0 JA |
1705 | if (cic) |
1706 | goto out; | |
1da177e4 | 1707 | |
e2d74ac0 JA |
1708 | cic = cfq_alloc_io_context(cfqd, gfp_mask); |
1709 | if (cic == NULL) | |
1710 | goto err; | |
1da177e4 | 1711 | |
4ac845a2 JA |
1712 | if (cfq_cic_link(cfqd, ioc, cic, gfp_mask)) |
1713 | goto err_free; | |
1714 | ||
1da177e4 | 1715 | out: |
fc46379d JA |
1716 | smp_read_barrier_depends(); |
1717 | if (unlikely(ioc->ioprio_changed)) | |
1718 | cfq_ioc_set_ioprio(ioc); | |
1719 | ||
1da177e4 | 1720 | return cic; |
4ac845a2 JA |
1721 | err_free: |
1722 | cfq_cic_free(cic); | |
1da177e4 LT |
1723 | err: |
1724 | put_io_context(ioc); | |
1725 | return NULL; | |
1726 | } | |
1727 | ||
22e2c507 JA |
1728 | static void |
1729 | cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic) | |
1da177e4 | 1730 | { |
aaf1228d JA |
1731 | unsigned long elapsed = jiffies - cic->last_end_request; |
1732 | unsigned long ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle); | |
db3b5848 | 1733 | |
22e2c507 JA |
1734 | cic->ttime_samples = (7*cic->ttime_samples + 256) / 8; |
1735 | cic->ttime_total = (7*cic->ttime_total + 256*ttime) / 8; | |
1736 | cic->ttime_mean = (cic->ttime_total + 128) / cic->ttime_samples; | |
1737 | } | |
1da177e4 | 1738 | |
206dc69b | 1739 | static void |
6d048f53 JA |
1740 | cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_io_context *cic, |
1741 | struct request *rq) | |
206dc69b JA |
1742 | { |
1743 | sector_t sdist; | |
1744 | u64 total; | |
1745 | ||
5e705374 JA |
1746 | if (cic->last_request_pos < rq->sector) |
1747 | sdist = rq->sector - cic->last_request_pos; | |
206dc69b | 1748 | else |
5e705374 | 1749 | sdist = cic->last_request_pos - rq->sector; |
206dc69b JA |
1750 | |
1751 | /* | |
1752 | * Don't allow the seek distance to get too large from the | |
1753 | * odd fragment, pagein, etc | |
1754 | */ | |
1755 | if (cic->seek_samples <= 60) /* second&third seek */ | |
1756 | sdist = min(sdist, (cic->seek_mean * 4) + 2*1024*1024); | |
1757 | else | |
1758 | sdist = min(sdist, (cic->seek_mean * 4) + 2*1024*64); | |
1759 | ||
1760 | cic->seek_samples = (7*cic->seek_samples + 256) / 8; | |
1761 | cic->seek_total = (7*cic->seek_total + (u64)256*sdist) / 8; | |
1762 | total = cic->seek_total + (cic->seek_samples/2); | |
1763 | do_div(total, cic->seek_samples); | |
1764 | cic->seek_mean = (sector_t)total; | |
1765 | } | |
1da177e4 | 1766 | |
22e2c507 JA |
1767 | /* |
1768 | * Disable idle window if the process thinks too long or seeks so much that | |
1769 | * it doesn't matter | |
1770 | */ | |
1771 | static void | |
1772 | cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
1773 | struct cfq_io_context *cic) | |
1774 | { | |
7b679138 | 1775 | int old_idle, enable_idle; |
1be92f2f | 1776 | |
0871714e JA |
1777 | /* |
1778 | * Don't idle for async or idle io prio class | |
1779 | */ | |
1780 | if (!cfq_cfqq_sync(cfqq) || cfq_class_idle(cfqq)) | |
1be92f2f JA |
1781 | return; |
1782 | ||
c265a7f4 | 1783 | enable_idle = old_idle = cfq_cfqq_idle_window(cfqq); |
1da177e4 | 1784 | |
66dac98e | 1785 | if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle || |
caaa5f9f | 1786 | (cfqd->hw_tag && CIC_SEEKY(cic))) |
22e2c507 JA |
1787 | enable_idle = 0; |
1788 | else if (sample_valid(cic->ttime_samples)) { | |
1789 | if (cic->ttime_mean > cfqd->cfq_slice_idle) | |
1790 | enable_idle = 0; | |
1791 | else | |
1792 | enable_idle = 1; | |
1da177e4 LT |
1793 | } |
1794 | ||
7b679138 JA |
1795 | if (old_idle != enable_idle) { |
1796 | cfq_log_cfqq(cfqd, cfqq, "idle=%d", enable_idle); | |
1797 | if (enable_idle) | |
1798 | cfq_mark_cfqq_idle_window(cfqq); | |
1799 | else | |
1800 | cfq_clear_cfqq_idle_window(cfqq); | |
1801 | } | |
22e2c507 | 1802 | } |
1da177e4 | 1803 | |
22e2c507 JA |
1804 | /* |
1805 | * Check if new_cfqq should preempt the currently active queue. Return 0 for | |
1806 | * no or if we aren't sure, a 1 will cause a preempt. | |
1807 | */ | |
1808 | static int | |
1809 | cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, | |
5e705374 | 1810 | struct request *rq) |
22e2c507 | 1811 | { |
6d048f53 | 1812 | struct cfq_queue *cfqq; |
22e2c507 | 1813 | |
6d048f53 JA |
1814 | cfqq = cfqd->active_queue; |
1815 | if (!cfqq) | |
22e2c507 JA |
1816 | return 0; |
1817 | ||
6d048f53 JA |
1818 | if (cfq_slice_used(cfqq)) |
1819 | return 1; | |
1820 | ||
1821 | if (cfq_class_idle(new_cfqq)) | |
caaa5f9f | 1822 | return 0; |
22e2c507 JA |
1823 | |
1824 | if (cfq_class_idle(cfqq)) | |
1825 | return 1; | |
1e3335de | 1826 | |
374f84ac JA |
1827 | /* |
1828 | * if the new request is sync, but the currently running queue is | |
1829 | * not, let the sync request have priority. | |
1830 | */ | |
5e705374 | 1831 | if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq)) |
22e2c507 | 1832 | return 1; |
1e3335de | 1833 | |
374f84ac JA |
1834 | /* |
1835 | * So both queues are sync. Let the new request get disk time if | |
1836 | * it's a metadata request and the current queue is doing regular IO. | |
1837 | */ | |
1838 | if (rq_is_meta(rq) && !cfqq->meta_pending) | |
1839 | return 1; | |
22e2c507 | 1840 | |
3a9a3f6c DS |
1841 | /* |
1842 | * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice. | |
1843 | */ | |
1844 | if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq)) | |
1845 | return 1; | |
1846 | ||
1e3335de JA |
1847 | if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq)) |
1848 | return 0; | |
1849 | ||
1850 | /* | |
1851 | * if this request is as-good as one we would expect from the | |
1852 | * current cfqq, let it preempt | |
1853 | */ | |
6d048f53 | 1854 | if (cfq_rq_close(cfqd, rq)) |
1e3335de JA |
1855 | return 1; |
1856 | ||
22e2c507 JA |
1857 | return 0; |
1858 | } | |
1859 | ||
1860 | /* | |
1861 | * cfqq preempts the active queue. if we allowed preempt with no slice left, | |
1862 | * let it have half of its nominal slice. | |
1863 | */ | |
1864 | static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1865 | { | |
7b679138 | 1866 | cfq_log_cfqq(cfqd, cfqq, "preempt"); |
6084cdda | 1867 | cfq_slice_expired(cfqd, 1); |
22e2c507 | 1868 | |
bf572256 JA |
1869 | /* |
1870 | * Put the new queue at the front of the of the current list, | |
1871 | * so we know that it will be selected next. | |
1872 | */ | |
1873 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); | |
edd75ffd JA |
1874 | |
1875 | cfq_service_tree_add(cfqd, cfqq, 1); | |
bf572256 | 1876 | |
44f7c160 JA |
1877 | cfqq->slice_end = 0; |
1878 | cfq_mark_cfqq_slice_new(cfqq); | |
22e2c507 JA |
1879 | } |
1880 | ||
22e2c507 | 1881 | /* |
5e705374 | 1882 | * Called when a new fs request (rq) is added (to cfqq). Check if there's |
22e2c507 JA |
1883 | * something we should do about it |
1884 | */ | |
1885 | static void | |
5e705374 JA |
1886 | cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
1887 | struct request *rq) | |
22e2c507 | 1888 | { |
5e705374 | 1889 | struct cfq_io_context *cic = RQ_CIC(rq); |
12e9fddd | 1890 | |
45333d5a | 1891 | cfqd->rq_queued++; |
374f84ac JA |
1892 | if (rq_is_meta(rq)) |
1893 | cfqq->meta_pending++; | |
1894 | ||
9c2c38a1 | 1895 | cfq_update_io_thinktime(cfqd, cic); |
6d048f53 | 1896 | cfq_update_io_seektime(cfqd, cic, rq); |
9c2c38a1 JA |
1897 | cfq_update_idle_window(cfqd, cfqq, cic); |
1898 | ||
5e705374 | 1899 | cic->last_request_pos = rq->sector + rq->nr_sectors; |
22e2c507 JA |
1900 | |
1901 | if (cfqq == cfqd->active_queue) { | |
1902 | /* | |
b029195d JA |
1903 | * Remember that we saw a request from this process, but |
1904 | * don't start queuing just yet. Otherwise we risk seeing lots | |
1905 | * of tiny requests, because we disrupt the normal plugging | |
d6ceb25e JA |
1906 | * and merging. If the request is already larger than a single |
1907 | * page, let it rip immediately. For that case we assume that | |
2d870722 JA |
1908 | * merging is already done. Ditto for a busy system that |
1909 | * has other work pending, don't risk delaying until the | |
1910 | * idle timer unplug to continue working. | |
22e2c507 | 1911 | */ |
d6ceb25e | 1912 | if (cfq_cfqq_wait_request(cfqq)) { |
2d870722 JA |
1913 | if (blk_rq_bytes(rq) > PAGE_CACHE_SIZE || |
1914 | cfqd->busy_queues > 1) { | |
d6ceb25e JA |
1915 | del_timer(&cfqd->idle_slice_timer); |
1916 | blk_start_queueing(cfqd->queue); | |
1917 | } | |
b029195d | 1918 | cfq_mark_cfqq_must_dispatch(cfqq); |
d6ceb25e | 1919 | } |
5e705374 | 1920 | } else if (cfq_should_preempt(cfqd, cfqq, rq)) { |
22e2c507 JA |
1921 | /* |
1922 | * not the active queue - expire current slice if it is | |
1923 | * idle and has expired it's mean thinktime or this new queue | |
3a9a3f6c DS |
1924 | * has some old slice time left and is of higher priority or |
1925 | * this new queue is RT and the current one is BE | |
22e2c507 JA |
1926 | */ |
1927 | cfq_preempt_queue(cfqd, cfqq); | |
dc72ef4a | 1928 | blk_start_queueing(cfqd->queue); |
22e2c507 | 1929 | } |
1da177e4 LT |
1930 | } |
1931 | ||
165125e1 | 1932 | static void cfq_insert_request(struct request_queue *q, struct request *rq) |
1da177e4 | 1933 | { |
b4878f24 | 1934 | struct cfq_data *cfqd = q->elevator->elevator_data; |
5e705374 | 1935 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 | 1936 | |
7b679138 | 1937 | cfq_log_cfqq(cfqd, cfqq, "insert_request"); |
fd0928df | 1938 | cfq_init_prio_data(cfqq, RQ_CIC(rq)->ioc); |
1da177e4 | 1939 | |
5e705374 | 1940 | cfq_add_rq_rb(rq); |
1da177e4 | 1941 | |
22e2c507 JA |
1942 | list_add_tail(&rq->queuelist, &cfqq->fifo); |
1943 | ||
5e705374 | 1944 | cfq_rq_enqueued(cfqd, cfqq, rq); |
1da177e4 LT |
1945 | } |
1946 | ||
45333d5a AC |
1947 | /* |
1948 | * Update hw_tag based on peak queue depth over 50 samples under | |
1949 | * sufficient load. | |
1950 | */ | |
1951 | static void cfq_update_hw_tag(struct cfq_data *cfqd) | |
1952 | { | |
1953 | if (cfqd->rq_in_driver > cfqd->rq_in_driver_peak) | |
1954 | cfqd->rq_in_driver_peak = cfqd->rq_in_driver; | |
1955 | ||
1956 | if (cfqd->rq_queued <= CFQ_HW_QUEUE_MIN && | |
1957 | cfqd->rq_in_driver <= CFQ_HW_QUEUE_MIN) | |
1958 | return; | |
1959 | ||
1960 | if (cfqd->hw_tag_samples++ < 50) | |
1961 | return; | |
1962 | ||
1963 | if (cfqd->rq_in_driver_peak >= CFQ_HW_QUEUE_MIN) | |
1964 | cfqd->hw_tag = 1; | |
1965 | else | |
1966 | cfqd->hw_tag = 0; | |
1967 | ||
1968 | cfqd->hw_tag_samples = 0; | |
1969 | cfqd->rq_in_driver_peak = 0; | |
1970 | } | |
1971 | ||
165125e1 | 1972 | static void cfq_completed_request(struct request_queue *q, struct request *rq) |
1da177e4 | 1973 | { |
5e705374 | 1974 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
b4878f24 | 1975 | struct cfq_data *cfqd = cfqq->cfqd; |
5380a101 | 1976 | const int sync = rq_is_sync(rq); |
b4878f24 | 1977 | unsigned long now; |
1da177e4 | 1978 | |
b4878f24 | 1979 | now = jiffies; |
7b679138 | 1980 | cfq_log_cfqq(cfqd, cfqq, "complete"); |
1da177e4 | 1981 | |
45333d5a AC |
1982 | cfq_update_hw_tag(cfqd); |
1983 | ||
b4878f24 | 1984 | WARN_ON(!cfqd->rq_in_driver); |
6d048f53 | 1985 | WARN_ON(!cfqq->dispatched); |
b4878f24 | 1986 | cfqd->rq_in_driver--; |
6d048f53 | 1987 | cfqq->dispatched--; |
1da177e4 | 1988 | |
3ed9a296 JA |
1989 | if (cfq_cfqq_sync(cfqq)) |
1990 | cfqd->sync_flight--; | |
1991 | ||
b4878f24 JA |
1992 | if (!cfq_class_idle(cfqq)) |
1993 | cfqd->last_end_request = now; | |
3b18152c | 1994 | |
caaa5f9f | 1995 | if (sync) |
5e705374 | 1996 | RQ_CIC(rq)->last_end_request = now; |
caaa5f9f JA |
1997 | |
1998 | /* | |
1999 | * If this is the active queue, check if it needs to be expired, | |
2000 | * or if we want to idle in case it has no pending requests. | |
2001 | */ | |
2002 | if (cfqd->active_queue == cfqq) { | |
44f7c160 JA |
2003 | if (cfq_cfqq_slice_new(cfqq)) { |
2004 | cfq_set_prio_slice(cfqd, cfqq); | |
2005 | cfq_clear_cfqq_slice_new(cfqq); | |
2006 | } | |
0871714e | 2007 | if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq)) |
6084cdda | 2008 | cfq_slice_expired(cfqd, 1); |
aeb6fafb JA |
2009 | else if (sync && !rq_noidle(rq) && |
2010 | RB_EMPTY_ROOT(&cfqq->sort_list)) { | |
6d048f53 | 2011 | cfq_arm_slice_timer(cfqd); |
aeb6fafb | 2012 | } |
caaa5f9f | 2013 | } |
6d048f53 JA |
2014 | |
2015 | if (!cfqd->rq_in_driver) | |
2016 | cfq_schedule_dispatch(cfqd); | |
1da177e4 LT |
2017 | } |
2018 | ||
22e2c507 JA |
2019 | /* |
2020 | * we temporarily boost lower priority queues if they are holding fs exclusive | |
2021 | * resources. they are boosted to normal prio (CLASS_BE/4) | |
2022 | */ | |
2023 | static void cfq_prio_boost(struct cfq_queue *cfqq) | |
1da177e4 | 2024 | { |
22e2c507 JA |
2025 | if (has_fs_excl()) { |
2026 | /* | |
2027 | * boost idle prio on transactions that would lock out other | |
2028 | * users of the filesystem | |
2029 | */ | |
2030 | if (cfq_class_idle(cfqq)) | |
2031 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
2032 | if (cfqq->ioprio > IOPRIO_NORM) | |
2033 | cfqq->ioprio = IOPRIO_NORM; | |
2034 | } else { | |
2035 | /* | |
2036 | * check if we need to unboost the queue | |
2037 | */ | |
2038 | if (cfqq->ioprio_class != cfqq->org_ioprio_class) | |
2039 | cfqq->ioprio_class = cfqq->org_ioprio_class; | |
2040 | if (cfqq->ioprio != cfqq->org_ioprio) | |
2041 | cfqq->ioprio = cfqq->org_ioprio; | |
2042 | } | |
22e2c507 | 2043 | } |
1da177e4 | 2044 | |
89850f7e | 2045 | static inline int __cfq_may_queue(struct cfq_queue *cfqq) |
22e2c507 | 2046 | { |
3b18152c | 2047 | if ((cfq_cfqq_wait_request(cfqq) || cfq_cfqq_must_alloc(cfqq)) && |
99f95e52 | 2048 | !cfq_cfqq_must_alloc_slice(cfqq)) { |
3b18152c | 2049 | cfq_mark_cfqq_must_alloc_slice(cfqq); |
22e2c507 | 2050 | return ELV_MQUEUE_MUST; |
3b18152c | 2051 | } |
1da177e4 | 2052 | |
22e2c507 | 2053 | return ELV_MQUEUE_MAY; |
22e2c507 JA |
2054 | } |
2055 | ||
165125e1 | 2056 | static int cfq_may_queue(struct request_queue *q, int rw) |
22e2c507 JA |
2057 | { |
2058 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
2059 | struct task_struct *tsk = current; | |
91fac317 | 2060 | struct cfq_io_context *cic; |
22e2c507 JA |
2061 | struct cfq_queue *cfqq; |
2062 | ||
2063 | /* | |
2064 | * don't force setup of a queue from here, as a call to may_queue | |
2065 | * does not necessarily imply that a request actually will be queued. | |
2066 | * so just lookup a possibly existing queue, or return 'may queue' | |
2067 | * if that fails | |
2068 | */ | |
4ac845a2 | 2069 | cic = cfq_cic_lookup(cfqd, tsk->io_context); |
91fac317 VT |
2070 | if (!cic) |
2071 | return ELV_MQUEUE_MAY; | |
2072 | ||
b0b78f81 | 2073 | cfqq = cic_to_cfqq(cic, rw_is_sync(rw)); |
22e2c507 | 2074 | if (cfqq) { |
fd0928df | 2075 | cfq_init_prio_data(cfqq, cic->ioc); |
22e2c507 JA |
2076 | cfq_prio_boost(cfqq); |
2077 | ||
89850f7e | 2078 | return __cfq_may_queue(cfqq); |
22e2c507 JA |
2079 | } |
2080 | ||
2081 | return ELV_MQUEUE_MAY; | |
1da177e4 LT |
2082 | } |
2083 | ||
1da177e4 LT |
2084 | /* |
2085 | * queue lock held here | |
2086 | */ | |
bb37b94c | 2087 | static void cfq_put_request(struct request *rq) |
1da177e4 | 2088 | { |
5e705374 | 2089 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
1da177e4 | 2090 | |
5e705374 | 2091 | if (cfqq) { |
22e2c507 | 2092 | const int rw = rq_data_dir(rq); |
1da177e4 | 2093 | |
22e2c507 JA |
2094 | BUG_ON(!cfqq->allocated[rw]); |
2095 | cfqq->allocated[rw]--; | |
1da177e4 | 2096 | |
5e705374 | 2097 | put_io_context(RQ_CIC(rq)->ioc); |
1da177e4 | 2098 | |
1da177e4 | 2099 | rq->elevator_private = NULL; |
5e705374 | 2100 | rq->elevator_private2 = NULL; |
1da177e4 | 2101 | |
1da177e4 LT |
2102 | cfq_put_queue(cfqq); |
2103 | } | |
2104 | } | |
2105 | ||
2106 | /* | |
22e2c507 | 2107 | * Allocate cfq data structures associated with this request. |
1da177e4 | 2108 | */ |
22e2c507 | 2109 | static int |
165125e1 | 2110 | cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask) |
1da177e4 LT |
2111 | { |
2112 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
2113 | struct cfq_io_context *cic; | |
2114 | const int rw = rq_data_dir(rq); | |
7749a8d4 | 2115 | const int is_sync = rq_is_sync(rq); |
22e2c507 | 2116 | struct cfq_queue *cfqq; |
1da177e4 LT |
2117 | unsigned long flags; |
2118 | ||
2119 | might_sleep_if(gfp_mask & __GFP_WAIT); | |
2120 | ||
e2d74ac0 | 2121 | cic = cfq_get_io_context(cfqd, gfp_mask); |
22e2c507 | 2122 | |
1da177e4 LT |
2123 | spin_lock_irqsave(q->queue_lock, flags); |
2124 | ||
22e2c507 JA |
2125 | if (!cic) |
2126 | goto queue_fail; | |
2127 | ||
91fac317 VT |
2128 | cfqq = cic_to_cfqq(cic, is_sync); |
2129 | if (!cfqq) { | |
fd0928df | 2130 | cfqq = cfq_get_queue(cfqd, is_sync, cic->ioc, gfp_mask); |
91fac317 | 2131 | |
22e2c507 JA |
2132 | if (!cfqq) |
2133 | goto queue_fail; | |
1da177e4 | 2134 | |
91fac317 VT |
2135 | cic_set_cfqq(cic, cfqq, is_sync); |
2136 | } | |
1da177e4 LT |
2137 | |
2138 | cfqq->allocated[rw]++; | |
3b18152c | 2139 | cfq_clear_cfqq_must_alloc(cfqq); |
22e2c507 | 2140 | atomic_inc(&cfqq->ref); |
1da177e4 | 2141 | |
5e705374 | 2142 | spin_unlock_irqrestore(q->queue_lock, flags); |
3b18152c | 2143 | |
5e705374 JA |
2144 | rq->elevator_private = cic; |
2145 | rq->elevator_private2 = cfqq; | |
2146 | return 0; | |
1da177e4 | 2147 | |
22e2c507 JA |
2148 | queue_fail: |
2149 | if (cic) | |
2150 | put_io_context(cic->ioc); | |
89850f7e | 2151 | |
3b18152c | 2152 | cfq_schedule_dispatch(cfqd); |
1da177e4 | 2153 | spin_unlock_irqrestore(q->queue_lock, flags); |
7b679138 | 2154 | cfq_log(cfqd, "set_request fail"); |
1da177e4 LT |
2155 | return 1; |
2156 | } | |
2157 | ||
65f27f38 | 2158 | static void cfq_kick_queue(struct work_struct *work) |
22e2c507 | 2159 | { |
65f27f38 DH |
2160 | struct cfq_data *cfqd = |
2161 | container_of(work, struct cfq_data, unplug_work); | |
165125e1 | 2162 | struct request_queue *q = cfqd->queue; |
22e2c507 | 2163 | |
40bb54d1 | 2164 | spin_lock_irq(q->queue_lock); |
dc72ef4a | 2165 | blk_start_queueing(q); |
40bb54d1 | 2166 | spin_unlock_irq(q->queue_lock); |
22e2c507 JA |
2167 | } |
2168 | ||
2169 | /* | |
2170 | * Timer running if the active_queue is currently idling inside its time slice | |
2171 | */ | |
2172 | static void cfq_idle_slice_timer(unsigned long data) | |
2173 | { | |
2174 | struct cfq_data *cfqd = (struct cfq_data *) data; | |
2175 | struct cfq_queue *cfqq; | |
2176 | unsigned long flags; | |
3c6bd2f8 | 2177 | int timed_out = 1; |
22e2c507 | 2178 | |
7b679138 JA |
2179 | cfq_log(cfqd, "idle timer fired"); |
2180 | ||
22e2c507 JA |
2181 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); |
2182 | ||
fe094d98 JA |
2183 | cfqq = cfqd->active_queue; |
2184 | if (cfqq) { | |
3c6bd2f8 JA |
2185 | timed_out = 0; |
2186 | ||
b029195d JA |
2187 | /* |
2188 | * We saw a request before the queue expired, let it through | |
2189 | */ | |
2190 | if (cfq_cfqq_must_dispatch(cfqq)) | |
2191 | goto out_kick; | |
2192 | ||
22e2c507 JA |
2193 | /* |
2194 | * expired | |
2195 | */ | |
44f7c160 | 2196 | if (cfq_slice_used(cfqq)) |
22e2c507 JA |
2197 | goto expire; |
2198 | ||
2199 | /* | |
2200 | * only expire and reinvoke request handler, if there are | |
2201 | * other queues with pending requests | |
2202 | */ | |
caaa5f9f | 2203 | if (!cfqd->busy_queues) |
22e2c507 | 2204 | goto out_cont; |
22e2c507 JA |
2205 | |
2206 | /* | |
2207 | * not expired and it has a request pending, let it dispatch | |
2208 | */ | |
75e50984 | 2209 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
22e2c507 | 2210 | goto out_kick; |
22e2c507 JA |
2211 | } |
2212 | expire: | |
6084cdda | 2213 | cfq_slice_expired(cfqd, timed_out); |
22e2c507 | 2214 | out_kick: |
3b18152c | 2215 | cfq_schedule_dispatch(cfqd); |
22e2c507 JA |
2216 | out_cont: |
2217 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
2218 | } | |
2219 | ||
3b18152c JA |
2220 | static void cfq_shutdown_timer_wq(struct cfq_data *cfqd) |
2221 | { | |
2222 | del_timer_sync(&cfqd->idle_slice_timer); | |
64d01dc9 | 2223 | cancel_work_sync(&cfqd->unplug_work); |
3b18152c | 2224 | } |
22e2c507 | 2225 | |
c2dea2d1 VT |
2226 | static void cfq_put_async_queues(struct cfq_data *cfqd) |
2227 | { | |
2228 | int i; | |
2229 | ||
2230 | for (i = 0; i < IOPRIO_BE_NR; i++) { | |
2231 | if (cfqd->async_cfqq[0][i]) | |
2232 | cfq_put_queue(cfqd->async_cfqq[0][i]); | |
2233 | if (cfqd->async_cfqq[1][i]) | |
2234 | cfq_put_queue(cfqd->async_cfqq[1][i]); | |
c2dea2d1 | 2235 | } |
2389d1ef ON |
2236 | |
2237 | if (cfqd->async_idle_cfqq) | |
2238 | cfq_put_queue(cfqd->async_idle_cfqq); | |
c2dea2d1 VT |
2239 | } |
2240 | ||
b374d18a | 2241 | static void cfq_exit_queue(struct elevator_queue *e) |
1da177e4 | 2242 | { |
22e2c507 | 2243 | struct cfq_data *cfqd = e->elevator_data; |
165125e1 | 2244 | struct request_queue *q = cfqd->queue; |
22e2c507 | 2245 | |
3b18152c | 2246 | cfq_shutdown_timer_wq(cfqd); |
e2d74ac0 | 2247 | |
d9ff4187 | 2248 | spin_lock_irq(q->queue_lock); |
e2d74ac0 | 2249 | |
d9ff4187 | 2250 | if (cfqd->active_queue) |
6084cdda | 2251 | __cfq_slice_expired(cfqd, cfqd->active_queue, 0); |
e2d74ac0 JA |
2252 | |
2253 | while (!list_empty(&cfqd->cic_list)) { | |
d9ff4187 AV |
2254 | struct cfq_io_context *cic = list_entry(cfqd->cic_list.next, |
2255 | struct cfq_io_context, | |
2256 | queue_list); | |
89850f7e JA |
2257 | |
2258 | __cfq_exit_single_io_context(cfqd, cic); | |
d9ff4187 | 2259 | } |
e2d74ac0 | 2260 | |
c2dea2d1 | 2261 | cfq_put_async_queues(cfqd); |
15c31be4 | 2262 | |
d9ff4187 | 2263 | spin_unlock_irq(q->queue_lock); |
a90d742e AV |
2264 | |
2265 | cfq_shutdown_timer_wq(cfqd); | |
2266 | ||
a90d742e | 2267 | kfree(cfqd); |
1da177e4 LT |
2268 | } |
2269 | ||
165125e1 | 2270 | static void *cfq_init_queue(struct request_queue *q) |
1da177e4 LT |
2271 | { |
2272 | struct cfq_data *cfqd; | |
1da177e4 | 2273 | |
94f6030c | 2274 | cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL | __GFP_ZERO, q->node); |
1da177e4 | 2275 | if (!cfqd) |
bc1c1169 | 2276 | return NULL; |
1da177e4 | 2277 | |
cc09e299 | 2278 | cfqd->service_tree = CFQ_RB_ROOT; |
d9ff4187 | 2279 | INIT_LIST_HEAD(&cfqd->cic_list); |
1da177e4 | 2280 | |
1da177e4 | 2281 | cfqd->queue = q; |
1da177e4 | 2282 | |
22e2c507 JA |
2283 | init_timer(&cfqd->idle_slice_timer); |
2284 | cfqd->idle_slice_timer.function = cfq_idle_slice_timer; | |
2285 | cfqd->idle_slice_timer.data = (unsigned long) cfqd; | |
2286 | ||
65f27f38 | 2287 | INIT_WORK(&cfqd->unplug_work, cfq_kick_queue); |
22e2c507 | 2288 | |
b70c864d | 2289 | cfqd->last_end_request = jiffies; |
1da177e4 | 2290 | cfqd->cfq_quantum = cfq_quantum; |
22e2c507 JA |
2291 | cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; |
2292 | cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; | |
1da177e4 LT |
2293 | cfqd->cfq_back_max = cfq_back_max; |
2294 | cfqd->cfq_back_penalty = cfq_back_penalty; | |
22e2c507 JA |
2295 | cfqd->cfq_slice[0] = cfq_slice_async; |
2296 | cfqd->cfq_slice[1] = cfq_slice_sync; | |
2297 | cfqd->cfq_slice_async_rq = cfq_slice_async_rq; | |
2298 | cfqd->cfq_slice_idle = cfq_slice_idle; | |
45333d5a | 2299 | cfqd->hw_tag = 1; |
3b18152c | 2300 | |
bc1c1169 | 2301 | return cfqd; |
1da177e4 LT |
2302 | } |
2303 | ||
2304 | static void cfq_slab_kill(void) | |
2305 | { | |
d6de8be7 JA |
2306 | /* |
2307 | * Caller already ensured that pending RCU callbacks are completed, | |
2308 | * so we should have no busy allocations at this point. | |
2309 | */ | |
1da177e4 LT |
2310 | if (cfq_pool) |
2311 | kmem_cache_destroy(cfq_pool); | |
2312 | if (cfq_ioc_pool) | |
2313 | kmem_cache_destroy(cfq_ioc_pool); | |
2314 | } | |
2315 | ||
2316 | static int __init cfq_slab_setup(void) | |
2317 | { | |
0a31bd5f | 2318 | cfq_pool = KMEM_CACHE(cfq_queue, 0); |
1da177e4 LT |
2319 | if (!cfq_pool) |
2320 | goto fail; | |
2321 | ||
34e6bbf2 | 2322 | cfq_ioc_pool = KMEM_CACHE(cfq_io_context, 0); |
1da177e4 LT |
2323 | if (!cfq_ioc_pool) |
2324 | goto fail; | |
2325 | ||
2326 | return 0; | |
2327 | fail: | |
2328 | cfq_slab_kill(); | |
2329 | return -ENOMEM; | |
2330 | } | |
2331 | ||
1da177e4 LT |
2332 | /* |
2333 | * sysfs parts below --> | |
2334 | */ | |
1da177e4 LT |
2335 | static ssize_t |
2336 | cfq_var_show(unsigned int var, char *page) | |
2337 | { | |
2338 | return sprintf(page, "%d\n", var); | |
2339 | } | |
2340 | ||
2341 | static ssize_t | |
2342 | cfq_var_store(unsigned int *var, const char *page, size_t count) | |
2343 | { | |
2344 | char *p = (char *) page; | |
2345 | ||
2346 | *var = simple_strtoul(p, &p, 10); | |
2347 | return count; | |
2348 | } | |
2349 | ||
1da177e4 | 2350 | #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ |
b374d18a | 2351 | static ssize_t __FUNC(struct elevator_queue *e, char *page) \ |
1da177e4 | 2352 | { \ |
3d1ab40f | 2353 | struct cfq_data *cfqd = e->elevator_data; \ |
1da177e4 LT |
2354 | unsigned int __data = __VAR; \ |
2355 | if (__CONV) \ | |
2356 | __data = jiffies_to_msecs(__data); \ | |
2357 | return cfq_var_show(__data, (page)); \ | |
2358 | } | |
2359 | SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); | |
22e2c507 JA |
2360 | SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1); |
2361 | SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1); | |
e572ec7e AV |
2362 | SHOW_FUNCTION(cfq_back_seek_max_show, cfqd->cfq_back_max, 0); |
2363 | SHOW_FUNCTION(cfq_back_seek_penalty_show, cfqd->cfq_back_penalty, 0); | |
22e2c507 JA |
2364 | SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1); |
2365 | SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1); | |
2366 | SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1); | |
2367 | SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0); | |
1da177e4 LT |
2368 | #undef SHOW_FUNCTION |
2369 | ||
2370 | #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ | |
b374d18a | 2371 | static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \ |
1da177e4 | 2372 | { \ |
3d1ab40f | 2373 | struct cfq_data *cfqd = e->elevator_data; \ |
1da177e4 LT |
2374 | unsigned int __data; \ |
2375 | int ret = cfq_var_store(&__data, (page), count); \ | |
2376 | if (__data < (MIN)) \ | |
2377 | __data = (MIN); \ | |
2378 | else if (__data > (MAX)) \ | |
2379 | __data = (MAX); \ | |
2380 | if (__CONV) \ | |
2381 | *(__PTR) = msecs_to_jiffies(__data); \ | |
2382 | else \ | |
2383 | *(__PTR) = __data; \ | |
2384 | return ret; \ | |
2385 | } | |
2386 | STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); | |
fe094d98 JA |
2387 | STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, |
2388 | UINT_MAX, 1); | |
2389 | STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, | |
2390 | UINT_MAX, 1); | |
e572ec7e | 2391 | STORE_FUNCTION(cfq_back_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); |
fe094d98 JA |
2392 | STORE_FUNCTION(cfq_back_seek_penalty_store, &cfqd->cfq_back_penalty, 1, |
2393 | UINT_MAX, 0); | |
22e2c507 JA |
2394 | STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1); |
2395 | STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1); | |
2396 | STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1); | |
fe094d98 JA |
2397 | STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, |
2398 | UINT_MAX, 0); | |
1da177e4 LT |
2399 | #undef STORE_FUNCTION |
2400 | ||
e572ec7e AV |
2401 | #define CFQ_ATTR(name) \ |
2402 | __ATTR(name, S_IRUGO|S_IWUSR, cfq_##name##_show, cfq_##name##_store) | |
2403 | ||
2404 | static struct elv_fs_entry cfq_attrs[] = { | |
2405 | CFQ_ATTR(quantum), | |
e572ec7e AV |
2406 | CFQ_ATTR(fifo_expire_sync), |
2407 | CFQ_ATTR(fifo_expire_async), | |
2408 | CFQ_ATTR(back_seek_max), | |
2409 | CFQ_ATTR(back_seek_penalty), | |
2410 | CFQ_ATTR(slice_sync), | |
2411 | CFQ_ATTR(slice_async), | |
2412 | CFQ_ATTR(slice_async_rq), | |
2413 | CFQ_ATTR(slice_idle), | |
e572ec7e | 2414 | __ATTR_NULL |
1da177e4 LT |
2415 | }; |
2416 | ||
1da177e4 LT |
2417 | static struct elevator_type iosched_cfq = { |
2418 | .ops = { | |
2419 | .elevator_merge_fn = cfq_merge, | |
2420 | .elevator_merged_fn = cfq_merged_request, | |
2421 | .elevator_merge_req_fn = cfq_merged_requests, | |
da775265 | 2422 | .elevator_allow_merge_fn = cfq_allow_merge, |
b4878f24 | 2423 | .elevator_dispatch_fn = cfq_dispatch_requests, |
1da177e4 | 2424 | .elevator_add_req_fn = cfq_insert_request, |
b4878f24 | 2425 | .elevator_activate_req_fn = cfq_activate_request, |
1da177e4 LT |
2426 | .elevator_deactivate_req_fn = cfq_deactivate_request, |
2427 | .elevator_queue_empty_fn = cfq_queue_empty, | |
2428 | .elevator_completed_req_fn = cfq_completed_request, | |
21183b07 JA |
2429 | .elevator_former_req_fn = elv_rb_former_request, |
2430 | .elevator_latter_req_fn = elv_rb_latter_request, | |
1da177e4 LT |
2431 | .elevator_set_req_fn = cfq_set_request, |
2432 | .elevator_put_req_fn = cfq_put_request, | |
2433 | .elevator_may_queue_fn = cfq_may_queue, | |
2434 | .elevator_init_fn = cfq_init_queue, | |
2435 | .elevator_exit_fn = cfq_exit_queue, | |
fc46379d | 2436 | .trim = cfq_free_io_context, |
1da177e4 | 2437 | }, |
3d1ab40f | 2438 | .elevator_attrs = cfq_attrs, |
1da177e4 LT |
2439 | .elevator_name = "cfq", |
2440 | .elevator_owner = THIS_MODULE, | |
2441 | }; | |
2442 | ||
2443 | static int __init cfq_init(void) | |
2444 | { | |
22e2c507 JA |
2445 | /* |
2446 | * could be 0 on HZ < 1000 setups | |
2447 | */ | |
2448 | if (!cfq_slice_async) | |
2449 | cfq_slice_async = 1; | |
2450 | if (!cfq_slice_idle) | |
2451 | cfq_slice_idle = 1; | |
2452 | ||
1da177e4 LT |
2453 | if (cfq_slab_setup()) |
2454 | return -ENOMEM; | |
2455 | ||
2fdd82bd | 2456 | elv_register(&iosched_cfq); |
1da177e4 | 2457 | |
2fdd82bd | 2458 | return 0; |
1da177e4 LT |
2459 | } |
2460 | ||
2461 | static void __exit cfq_exit(void) | |
2462 | { | |
6e9a4738 | 2463 | DECLARE_COMPLETION_ONSTACK(all_gone); |
1da177e4 | 2464 | elv_unregister(&iosched_cfq); |
334e94de | 2465 | ioc_gone = &all_gone; |
fba82272 OH |
2466 | /* ioc_gone's update must be visible before reading ioc_count */ |
2467 | smp_wmb(); | |
d6de8be7 JA |
2468 | |
2469 | /* | |
2470 | * this also protects us from entering cfq_slab_kill() with | |
2471 | * pending RCU callbacks | |
2472 | */ | |
4050cf16 | 2473 | if (elv_ioc_count_read(ioc_count)) |
9a11b4ed | 2474 | wait_for_completion(&all_gone); |
83521d3e | 2475 | cfq_slab_kill(); |
1da177e4 LT |
2476 | } |
2477 | ||
2478 | module_init(cfq_init); | |
2479 | module_exit(cfq_exit); | |
2480 | ||
2481 | MODULE_AUTHOR("Jens Axboe"); | |
2482 | MODULE_LICENSE("GPL"); | |
2483 | MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler"); |