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-rw-r--r--drivers/block/cfq-iosched.c1906
1 files changed, 1274 insertions, 632 deletions
diff --git a/drivers/block/cfq-iosched.c b/drivers/block/cfq-iosched.c
index 3ac47dde64da..35f6e569d5e5 100644
--- a/drivers/block/cfq-iosched.c
+++ b/drivers/block/cfq-iosched.c
@@ -21,22 +21,33 @@
21#include <linux/hash.h> 21#include <linux/hash.h>
22#include <linux/rbtree.h> 22#include <linux/rbtree.h>
23#include <linux/mempool.h> 23#include <linux/mempool.h>
24 24#include <linux/ioprio.h>
25static unsigned long max_elapsed_crq; 25#include <linux/writeback.h>
26static unsigned long max_elapsed_dispatch;
27 26
28/* 27/*
29 * tunables 28 * tunables
30 */ 29 */
31static int cfq_quantum = 4; /* max queue in one round of service */ 30static int cfq_quantum = 4; /* max queue in one round of service */
32static int cfq_queued = 8; /* minimum rq allocate limit per-queue*/ 31static int cfq_queued = 8; /* minimum rq allocate limit per-queue*/
33static int cfq_service = HZ; /* period over which service is avg */ 32static int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 };
34static int cfq_fifo_expire_r = HZ / 2; /* fifo timeout for sync requests */
35static int cfq_fifo_expire_w = 5 * HZ; /* fifo timeout for async requests */
36static int cfq_fifo_rate = HZ / 8; /* fifo expiry rate */
37static int cfq_back_max = 16 * 1024; /* maximum backwards seek, in KiB */ 33static int cfq_back_max = 16 * 1024; /* maximum backwards seek, in KiB */
38static int cfq_back_penalty = 2; /* penalty of a backwards seek */ 34static int cfq_back_penalty = 2; /* penalty of a backwards seek */
39 35
36static int cfq_slice_sync = HZ / 10;
37static int cfq_slice_async = HZ / 50;
38static int cfq_slice_async_rq = 2;
39static int cfq_slice_idle = HZ / 50;
40
41#define CFQ_IDLE_GRACE (HZ / 10)
42#define CFQ_SLICE_SCALE (5)
43
44#define CFQ_KEY_ASYNC (0)
45
46/*
47 * disable queueing at the driver/hardware level
48 */
49static int cfq_max_depth = 1;
50
40/* 51/*
41 * for the hash of cfqq inside the cfqd 52 * for the hash of cfqq inside the cfqd
42 */ 53 */
@@ -55,6 +66,7 @@ static int cfq_back_penalty = 2; /* penalty of a backwards seek */
55#define list_entry_hash(ptr) hlist_entry((ptr), struct cfq_rq, hash) 66#define list_entry_hash(ptr) hlist_entry((ptr), struct cfq_rq, hash)
56 67
57#define list_entry_cfqq(ptr) list_entry((ptr), struct cfq_queue, cfq_list) 68#define list_entry_cfqq(ptr) list_entry((ptr), struct cfq_queue, cfq_list)
69#define list_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
58 70
59#define RQ_DATA(rq) (rq)->elevator_private 71#define RQ_DATA(rq) (rq)->elevator_private
60 72
@@ -75,78 +87,101 @@ static int cfq_back_penalty = 2; /* penalty of a backwards seek */
75#define rb_entry_crq(node) rb_entry((node), struct cfq_rq, rb_node) 87#define rb_entry_crq(node) rb_entry((node), struct cfq_rq, rb_node)
76#define rq_rb_key(rq) (rq)->sector 88#define rq_rb_key(rq) (rq)->sector
77 89
78/*
79 * threshold for switching off non-tag accounting
80 */
81#define CFQ_MAX_TAG (4)
82
83/*
84 * sort key types and names
85 */
86enum {
87 CFQ_KEY_PGID,
88 CFQ_KEY_TGID,
89 CFQ_KEY_UID,
90 CFQ_KEY_GID,
91 CFQ_KEY_LAST,
92};
93
94static char *cfq_key_types[] = { "pgid", "tgid", "uid", "gid", NULL };
95
96static kmem_cache_t *crq_pool; 90static kmem_cache_t *crq_pool;
97static kmem_cache_t *cfq_pool; 91static kmem_cache_t *cfq_pool;
98static kmem_cache_t *cfq_ioc_pool; 92static kmem_cache_t *cfq_ioc_pool;
99 93
94#define CFQ_PRIO_LISTS IOPRIO_BE_NR
95#define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE)
96#define cfq_class_be(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_BE)
97#define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT)
98
99#define cfq_cfqq_sync(cfqq) ((cfqq)->key != CFQ_KEY_ASYNC)
100
101/*
102 * Per block device queue structure
103 */
100struct cfq_data { 104struct cfq_data {
101 struct list_head rr_list; 105 atomic_t ref;
106 request_queue_t *queue;
107
108 /*
109 * rr list of queues with requests and the count of them
110 */
111 struct list_head rr_list[CFQ_PRIO_LISTS];
112 struct list_head busy_rr;
113 struct list_head cur_rr;
114 struct list_head idle_rr;
115 unsigned int busy_queues;
116
117 /*
118 * non-ordered list of empty cfqq's
119 */
102 struct list_head empty_list; 120 struct list_head empty_list;
103 121
122 /*
123 * cfqq lookup hash
124 */
104 struct hlist_head *cfq_hash; 125 struct hlist_head *cfq_hash;
105 struct hlist_head *crq_hash;
106 126
107 /* queues on rr_list (ie they have pending requests */ 127 /*
108 unsigned int busy_queues; 128 * global crq hash for all queues
129 */
130 struct hlist_head *crq_hash;
109 131
110 unsigned int max_queued; 132 unsigned int max_queued;
111 133
112 atomic_t ref; 134 mempool_t *crq_pool;
113 135
114 int key_type; 136 int rq_in_driver;
115 137
116 mempool_t *crq_pool; 138 /*
139 * schedule slice state info
140 */
141 /*
142 * idle window management
143 */
144 struct timer_list idle_slice_timer;
145 struct work_struct unplug_work;
117 146
118 request_queue_t *queue; 147 struct cfq_queue *active_queue;
148 struct cfq_io_context *active_cic;
149 int cur_prio, cur_end_prio;
150 unsigned int dispatch_slice;
151
152 struct timer_list idle_class_timer;
119 153
120 sector_t last_sector; 154 sector_t last_sector;
155 unsigned long last_end_request;
121 156
122 int rq_in_driver; 157 unsigned int rq_starved;
123 158
124 /* 159 /*
125 * tunables, see top of file 160 * tunables, see top of file
126 */ 161 */
127 unsigned int cfq_quantum; 162 unsigned int cfq_quantum;
128 unsigned int cfq_queued; 163 unsigned int cfq_queued;
129 unsigned int cfq_fifo_expire_r; 164 unsigned int cfq_fifo_expire[2];
130 unsigned int cfq_fifo_expire_w;
131 unsigned int cfq_fifo_batch_expire;
132 unsigned int cfq_back_penalty; 165 unsigned int cfq_back_penalty;
133 unsigned int cfq_back_max; 166 unsigned int cfq_back_max;
134 unsigned int find_best_crq; 167 unsigned int cfq_slice[2];
135 168 unsigned int cfq_slice_async_rq;
136 unsigned int cfq_tagged; 169 unsigned int cfq_slice_idle;
170 unsigned int cfq_max_depth;
137}; 171};
138 172
173/*
174 * Per process-grouping structure
175 */
139struct cfq_queue { 176struct cfq_queue {
140 /* reference count */ 177 /* reference count */
141 atomic_t ref; 178 atomic_t ref;
142 /* parent cfq_data */ 179 /* parent cfq_data */
143 struct cfq_data *cfqd; 180 struct cfq_data *cfqd;
144 /* hash of mergeable requests */ 181 /* cfqq lookup hash */
145 struct hlist_node cfq_hash; 182 struct hlist_node cfq_hash;
146 /* hash key */ 183 /* hash key */
147 unsigned long key; 184 unsigned int key;
148 /* whether queue is on rr (or empty) list */
149 int on_rr;
150 /* on either rr or empty list of cfqd */ 185 /* on either rr or empty list of cfqd */
151 struct list_head cfq_list; 186 struct list_head cfq_list;
152 /* sorted list of pending requests */ 187 /* sorted list of pending requests */
@@ -158,21 +193,35 @@ struct cfq_queue {
158 /* currently allocated requests */ 193 /* currently allocated requests */
159 int allocated[2]; 194 int allocated[2];
160 /* fifo list of requests in sort_list */ 195 /* fifo list of requests in sort_list */
161 struct list_head fifo[2]; 196 struct list_head fifo;
162 /* last time fifo expired */
163 unsigned long last_fifo_expire;
164
165 int key_type;
166
167 unsigned long service_start;
168 unsigned long service_used;
169 197
170 unsigned int max_rate; 198 unsigned long slice_start;
199 unsigned long slice_end;
200 unsigned long slice_left;
201 unsigned long service_last;
171 202
172 /* number of requests that have been handed to the driver */ 203 /* number of requests that have been handed to the driver */
173 int in_flight; 204 int in_flight;
174 /* number of currently allocated requests */ 205
175 int alloc_limit[2]; 206 /* io prio of this group */
207 unsigned short ioprio, org_ioprio;
208 unsigned short ioprio_class, org_ioprio_class;
209
210 /* whether queue is on rr (or empty) list */
211 unsigned on_rr : 1;
212 /* idle slice, waiting for new request submission */
213 unsigned wait_request : 1;
214 /* set when wait_request gets set, reset on first rq alloc */
215 unsigned must_alloc : 1;
216 /* only gets one must_alloc per slice */
217 unsigned must_alloc_slice : 1;
218 /* idle slice, request added, now waiting to dispatch it */
219 unsigned must_dispatch : 1;
220 /* fifo expire per-slice */
221 unsigned fifo_expire : 1;
222
223 unsigned idle_window : 1;
224 unsigned prio_changed : 1;
176}; 225};
177 226
178struct cfq_rq { 227struct cfq_rq {
@@ -184,42 +233,17 @@ struct cfq_rq {
184 struct cfq_queue *cfq_queue; 233 struct cfq_queue *cfq_queue;
185 struct cfq_io_context *io_context; 234 struct cfq_io_context *io_context;
186 235
187 unsigned long service_start; 236 unsigned in_flight : 1;
188 unsigned long queue_start; 237 unsigned accounted : 1;
189 238 unsigned is_sync : 1;
190 unsigned int in_flight : 1; 239 unsigned requeued : 1;
191 unsigned int accounted : 1;
192 unsigned int is_sync : 1;
193 unsigned int is_write : 1;
194}; 240};
195 241
196static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned long); 242static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int);
197static void cfq_dispatch_sort(request_queue_t *, struct cfq_rq *); 243static void cfq_dispatch_sort(request_queue_t *, struct cfq_rq *);
198static void cfq_update_next_crq(struct cfq_rq *);
199static void cfq_put_cfqd(struct cfq_data *cfqd); 244static void cfq_put_cfqd(struct cfq_data *cfqd);
200 245
201/* 246#define process_sync(tsk) ((tsk)->flags & PF_SYNCWRITE)
202 * what the fairness is based on (ie how processes are grouped and
203 * differentiated)
204 */
205static inline unsigned long
206cfq_hash_key(struct cfq_data *cfqd, struct task_struct *tsk)
207{
208 /*
209 * optimize this so that ->key_type is the offset into the struct
210 */
211 switch (cfqd->key_type) {
212 case CFQ_KEY_PGID:
213 return process_group(tsk);
214 default:
215 case CFQ_KEY_TGID:
216 return tsk->tgid;
217 case CFQ_KEY_UID:
218 return tsk->uid;
219 case CFQ_KEY_GID:
220 return tsk->gid;
221 }
222}
223 247
224/* 248/*
225 * lots of deadline iosched dupes, can be abstracted later... 249 * lots of deadline iosched dupes, can be abstracted later...
@@ -235,16 +259,12 @@ static void cfq_remove_merge_hints(request_queue_t *q, struct cfq_rq *crq)
235 259
236 if (q->last_merge == crq->request) 260 if (q->last_merge == crq->request)
237 q->last_merge = NULL; 261 q->last_merge = NULL;
238
239 cfq_update_next_crq(crq);
240} 262}
241 263
242static inline void cfq_add_crq_hash(struct cfq_data *cfqd, struct cfq_rq *crq) 264static inline void cfq_add_crq_hash(struct cfq_data *cfqd, struct cfq_rq *crq)
243{ 265{
244 const int hash_idx = CFQ_MHASH_FN(rq_hash_key(crq->request)); 266 const int hash_idx = CFQ_MHASH_FN(rq_hash_key(crq->request));
245 267
246 BUG_ON(!hlist_unhashed(&crq->hash));
247
248 hlist_add_head(&crq->hash, &cfqd->crq_hash[hash_idx]); 268 hlist_add_head(&crq->hash, &cfqd->crq_hash[hash_idx]);
249} 269}
250 270
@@ -257,8 +277,6 @@ static struct request *cfq_find_rq_hash(struct cfq_data *cfqd, sector_t offset)
257 struct cfq_rq *crq = list_entry_hash(entry); 277 struct cfq_rq *crq = list_entry_hash(entry);
258 struct request *__rq = crq->request; 278 struct request *__rq = crq->request;
259 279
260 BUG_ON(hlist_unhashed(&crq->hash));
261
262 if (!rq_mergeable(__rq)) { 280 if (!rq_mergeable(__rq)) {
263 cfq_del_crq_hash(crq); 281 cfq_del_crq_hash(crq);
264 continue; 282 continue;
@@ -287,36 +305,16 @@ cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2)
287 return crq2; 305 return crq2;
288 if (crq2 == NULL) 306 if (crq2 == NULL)
289 return crq1; 307 return crq1;
308 if (crq1->requeued)
309 return crq1;
310 if (crq2->requeued)
311 return crq2;
290 312
291 s1 = crq1->request->sector; 313 s1 = crq1->request->sector;
292 s2 = crq2->request->sector; 314 s2 = crq2->request->sector;
293 315
294 last = cfqd->last_sector; 316 last = cfqd->last_sector;
295 317
296#if 0
297 if (!list_empty(&cfqd->queue->queue_head)) {
298 struct list_head *entry = &cfqd->queue->queue_head;
299 unsigned long distance = ~0UL;
300 struct request *rq;
301
302 while ((entry = entry->prev) != &cfqd->queue->queue_head) {
303 rq = list_entry_rq(entry);
304
305 if (blk_barrier_rq(rq))
306 break;
307
308 if (distance < abs(s1 - rq->sector + rq->nr_sectors)) {
309 distance = abs(s1 - rq->sector +rq->nr_sectors);
310 last = rq->sector + rq->nr_sectors;
311 }
312 if (distance < abs(s2 - rq->sector + rq->nr_sectors)) {
313 distance = abs(s2 - rq->sector +rq->nr_sectors);
314 last = rq->sector + rq->nr_sectors;
315 }
316 }
317 }
318#endif
319
320 /* 318 /*
321 * by definition, 1KiB is 2 sectors 319 * by definition, 1KiB is 2 sectors
322 */ 320 */
@@ -377,11 +375,13 @@ cfq_find_next_crq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
377 struct cfq_rq *crq_next = NULL, *crq_prev = NULL; 375 struct cfq_rq *crq_next = NULL, *crq_prev = NULL;
378 struct rb_node *rbnext, *rbprev; 376 struct rb_node *rbnext, *rbprev;
379 377
380 if (!ON_RB(&last->rb_node)) 378 if (ON_RB(&last->rb_node))
381 return NULL; 379 rbnext = rb_next(&last->rb_node);
382 380 else {
383 if ((rbnext = rb_next(&last->rb_node)) == NULL)
384 rbnext = rb_first(&cfqq->sort_list); 381 rbnext = rb_first(&cfqq->sort_list);
382 if (rbnext == &last->rb_node)
383 rbnext = NULL;
384 }
385 385
386 rbprev = rb_prev(&last->rb_node); 386 rbprev = rb_prev(&last->rb_node);
387 387
@@ -401,67 +401,53 @@ static void cfq_update_next_crq(struct cfq_rq *crq)
401 cfqq->next_crq = cfq_find_next_crq(cfqq->cfqd, cfqq, crq); 401 cfqq->next_crq = cfq_find_next_crq(cfqq->cfqd, cfqq, crq);
402} 402}
403 403
404static int cfq_check_sort_rr_list(struct cfq_queue *cfqq) 404static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted)
405{ 405{
406 struct list_head *head = &cfqq->cfqd->rr_list; 406 struct cfq_data *cfqd = cfqq->cfqd;
407 struct list_head *next, *prev; 407 struct list_head *list, *entry;
408
409 /*
410 * list might still be ordered
411 */
412 next = cfqq->cfq_list.next;
413 if (next != head) {
414 struct cfq_queue *cnext = list_entry_cfqq(next);
415 408
416 if (cfqq->service_used > cnext->service_used) 409 BUG_ON(!cfqq->on_rr);
417 return 1;
418 }
419 410
420 prev = cfqq->cfq_list.prev; 411 list_del(&cfqq->cfq_list);
421 if (prev != head) {
422 struct cfq_queue *cprev = list_entry_cfqq(prev);
423 412
424 if (cfqq->service_used < cprev->service_used) 413 if (cfq_class_rt(cfqq))
425 return 1; 414 list = &cfqd->cur_rr;
415 else if (cfq_class_idle(cfqq))
416 list = &cfqd->idle_rr;
417 else {
418 /*
419 * if cfqq has requests in flight, don't allow it to be
420 * found in cfq_set_active_queue before it has finished them.
421 * this is done to increase fairness between a process that
422 * has lots of io pending vs one that only generates one
423 * sporadically or synchronously
424 */
425 if (cfqq->in_flight)
426 list = &cfqd->busy_rr;
427 else
428 list = &cfqd->rr_list[cfqq->ioprio];
426 } 429 }
427 430
428 return 0; 431 /*
429} 432 * if queue was preempted, just add to front to be fair. busy_rr
430 433 * isn't sorted.
431static void cfq_sort_rr_list(struct cfq_queue *cfqq, int new_queue) 434 */
432{ 435 if (preempted || list == &cfqd->busy_rr) {
433 struct list_head *entry = &cfqq->cfqd->rr_list; 436 list_add(&cfqq->cfq_list, list);
434
435 if (!cfqq->on_rr)
436 return;
437 if (!new_queue && !cfq_check_sort_rr_list(cfqq))
438 return; 437 return;
439 438 }
440 list_del(&cfqq->cfq_list);
441 439
442 /* 440 /*
443 * sort by our mean service_used, sub-sort by in-flight requests 441 * sort by when queue was last serviced
444 */ 442 */
445 while ((entry = entry->prev) != &cfqq->cfqd->rr_list) { 443 entry = list;
444 while ((entry = entry->prev) != list) {
446 struct cfq_queue *__cfqq = list_entry_cfqq(entry); 445 struct cfq_queue *__cfqq = list_entry_cfqq(entry);
447 446
448 if (cfqq->service_used > __cfqq->service_used) 447 if (!__cfqq->service_last)
448 break;
449 if (time_before(__cfqq->service_last, cfqq->service_last))
449 break; 450 break;
450 else if (cfqq->service_used == __cfqq->service_used) {
451 struct list_head *prv;
452
453 while ((prv = entry->prev) != &cfqq->cfqd->rr_list) {
454 __cfqq = list_entry_cfqq(prv);
455
456 WARN_ON(__cfqq->service_used > cfqq->service_used);
457 if (cfqq->service_used != __cfqq->service_used)
458 break;
459 if (cfqq->in_flight > __cfqq->in_flight)
460 break;
461
462 entry = prv;
463 }
464 }
465 } 451 }
466 452
467 list_add(&cfqq->cfq_list, entry); 453 list_add(&cfqq->cfq_list, entry);
@@ -469,28 +455,24 @@ static void cfq_sort_rr_list(struct cfq_queue *cfqq, int new_queue)
469 455
470/* 456/*
471 * add to busy list of queues for service, trying to be fair in ordering 457 * add to busy list of queues for service, trying to be fair in ordering
472 * the pending list according to requests serviced 458 * the pending list according to last request service
473 */ 459 */
474static inline void 460static inline void
475cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) 461cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq, int requeue)
476{ 462{
477 /* 463 BUG_ON(cfqq->on_rr);
478 * it's currently on the empty list
479 */
480 cfqq->on_rr = 1; 464 cfqq->on_rr = 1;
481 cfqd->busy_queues++; 465 cfqd->busy_queues++;
482 466
483 if (time_after(jiffies, cfqq->service_start + cfq_service)) 467 cfq_resort_rr_list(cfqq, requeue);
484 cfqq->service_used >>= 3;
485
486 cfq_sort_rr_list(cfqq, 1);
487} 468}
488 469
489static inline void 470static inline void
490cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) 471cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
491{ 472{
492 list_move(&cfqq->cfq_list, &cfqd->empty_list); 473 BUG_ON(!cfqq->on_rr);
493 cfqq->on_rr = 0; 474 cfqq->on_rr = 0;
475 list_move(&cfqq->cfq_list, &cfqd->empty_list);
494 476
495 BUG_ON(!cfqd->busy_queues); 477 BUG_ON(!cfqd->busy_queues);
496 cfqd->busy_queues--; 478 cfqd->busy_queues--;
@@ -505,16 +487,17 @@ static inline void cfq_del_crq_rb(struct cfq_rq *crq)
505 487
506 if (ON_RB(&crq->rb_node)) { 488 if (ON_RB(&crq->rb_node)) {
507 struct cfq_data *cfqd = cfqq->cfqd; 489 struct cfq_data *cfqd = cfqq->cfqd;
490 const int sync = crq->is_sync;
508 491
509 BUG_ON(!cfqq->queued[crq->is_sync]); 492 BUG_ON(!cfqq->queued[sync]);
493 cfqq->queued[sync]--;
510 494
511 cfq_update_next_crq(crq); 495 cfq_update_next_crq(crq);
512 496
513 cfqq->queued[crq->is_sync]--;
514 rb_erase(&crq->rb_node, &cfqq->sort_list); 497 rb_erase(&crq->rb_node, &cfqq->sort_list);
515 RB_CLEAR_COLOR(&crq->rb_node); 498 RB_CLEAR_COLOR(&crq->rb_node);
516 499
517 if (RB_EMPTY(&cfqq->sort_list) && cfqq->on_rr) 500 if (cfqq->on_rr && RB_EMPTY(&cfqq->sort_list))
518 cfq_del_cfqq_rr(cfqd, cfqq); 501 cfq_del_cfqq_rr(cfqd, cfqq);
519 } 502 }
520} 503}
@@ -562,7 +545,7 @@ static void cfq_add_crq_rb(struct cfq_rq *crq)
562 rb_insert_color(&crq->rb_node, &cfqq->sort_list); 545 rb_insert_color(&crq->rb_node, &cfqq->sort_list);
563 546
564 if (!cfqq->on_rr) 547 if (!cfqq->on_rr)
565 cfq_add_cfqq_rr(cfqd, cfqq); 548 cfq_add_cfqq_rr(cfqd, cfqq, crq->requeued);
566 549
567 /* 550 /*
568 * check if this request is a better next-serve candidate 551 * check if this request is a better next-serve candidate
@@ -581,11 +564,10 @@ cfq_reposition_crq_rb(struct cfq_queue *cfqq, struct cfq_rq *crq)
581 cfq_add_crq_rb(crq); 564 cfq_add_crq_rb(crq);
582} 565}
583 566
584static struct request * 567static struct request *cfq_find_rq_rb(struct cfq_data *cfqd, sector_t sector)
585cfq_find_rq_rb(struct cfq_data *cfqd, sector_t sector) 568
586{ 569{
587 const unsigned long key = cfq_hash_key(cfqd, current); 570 struct cfq_queue *cfqq = cfq_find_cfq_hash(cfqd, current->pid);
588 struct cfq_queue *cfqq = cfq_find_cfq_hash(cfqd, key);
589 struct rb_node *n; 571 struct rb_node *n;
590 572
591 if (!cfqq) 573 if (!cfqq)
@@ -609,20 +591,23 @@ out:
609 591
610static void cfq_deactivate_request(request_queue_t *q, struct request *rq) 592static void cfq_deactivate_request(request_queue_t *q, struct request *rq)
611{ 593{
594 struct cfq_data *cfqd = q->elevator->elevator_data;
612 struct cfq_rq *crq = RQ_DATA(rq); 595 struct cfq_rq *crq = RQ_DATA(rq);
613 596
614 if (crq) { 597 if (crq) {
615 struct cfq_queue *cfqq = crq->cfq_queue; 598 struct cfq_queue *cfqq = crq->cfq_queue;
616 599
617 if (cfqq->cfqd->cfq_tagged) {
618 cfqq->service_used--;
619 cfq_sort_rr_list(cfqq, 0);
620 }
621
622 if (crq->accounted) { 600 if (crq->accounted) {
623 crq->accounted = 0; 601 crq->accounted = 0;
624 cfqq->cfqd->rq_in_driver--; 602 WARN_ON(!cfqd->rq_in_driver);
603 cfqd->rq_in_driver--;
604 }
605 if (crq->in_flight) {
606 crq->in_flight = 0;
607 WARN_ON(!cfqq->in_flight);
608 cfqq->in_flight--;
625 } 609 }
610 crq->requeued = 1;
626 } 611 }
627} 612}
628 613
@@ -640,11 +625,10 @@ static void cfq_remove_request(request_queue_t *q, struct request *rq)
640 struct cfq_rq *crq = RQ_DATA(rq); 625 struct cfq_rq *crq = RQ_DATA(rq);
641 626
642 if (crq) { 627 if (crq) {
643 cfq_remove_merge_hints(q, crq);
644 list_del_init(&rq->queuelist); 628 list_del_init(&rq->queuelist);
629 cfq_del_crq_rb(crq);
630 cfq_remove_merge_hints(q, crq);
645 631
646 if (crq->cfq_queue)
647 cfq_del_crq_rb(crq);
648 } 632 }
649} 633}
650 634
@@ -662,21 +646,15 @@ cfq_merge(request_queue_t *q, struct request **req, struct bio *bio)
662 } 646 }
663 647
664 __rq = cfq_find_rq_hash(cfqd, bio->bi_sector); 648 __rq = cfq_find_rq_hash(cfqd, bio->bi_sector);
665 if (__rq) { 649 if (__rq && elv_rq_merge_ok(__rq, bio)) {
666 BUG_ON(__rq->sector + __rq->nr_sectors != bio->bi_sector); 650 ret = ELEVATOR_BACK_MERGE;
667 651 goto out;
668 if (elv_rq_merge_ok(__rq, bio)) {
669 ret = ELEVATOR_BACK_MERGE;
670 goto out;
671 }
672 } 652 }
673 653
674 __rq = cfq_find_rq_rb(cfqd, bio->bi_sector + bio_sectors(bio)); 654 __rq = cfq_find_rq_rb(cfqd, bio->bi_sector + bio_sectors(bio));
675 if (__rq) { 655 if (__rq && elv_rq_merge_ok(__rq, bio)) {
676 if (elv_rq_merge_ok(__rq, bio)) { 656 ret = ELEVATOR_FRONT_MERGE;
677 ret = ELEVATOR_FRONT_MERGE; 657 goto out;
678 goto out;
679 }
680 } 658 }
681 659
682 return ELEVATOR_NO_MERGE; 660 return ELEVATOR_NO_MERGE;
@@ -709,20 +687,194 @@ static void
709cfq_merged_requests(request_queue_t *q, struct request *rq, 687cfq_merged_requests(request_queue_t *q, struct request *rq,
710 struct request *next) 688 struct request *next)
711{ 689{
712 struct cfq_rq *crq = RQ_DATA(rq);
713 struct cfq_rq *cnext = RQ_DATA(next);
714
715 cfq_merged_request(q, rq); 690 cfq_merged_request(q, rq);
716 691
717 if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist)) { 692 /*
718 if (time_before(cnext->queue_start, crq->queue_start)) { 693 * reposition in fifo if next is older than rq
719 list_move(&rq->queuelist, &next->queuelist); 694 */
720 crq->queue_start = cnext->queue_start; 695 if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) &&
696 time_before(next->start_time, rq->start_time))
697 list_move(&rq->queuelist, &next->queuelist);
698
699 cfq_remove_request(q, next);
700}
701
702static inline void
703__cfq_set_active_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
704{
705 if (cfqq) {
706 /*
707 * stop potential idle class queues waiting service
708 */
709 del_timer(&cfqd->idle_class_timer);
710
711 cfqq->slice_start = jiffies;
712 cfqq->slice_end = 0;
713 cfqq->slice_left = 0;
714 cfqq->must_alloc_slice = 0;
715 cfqq->fifo_expire = 0;
716 }
717
718 cfqd->active_queue = cfqq;
719}
720
721/*
722 * 0
723 * 0,1
724 * 0,1,2
725 * 0,1,2,3
726 * 0,1,2,3,4
727 * 0,1,2,3,4,5
728 * 0,1,2,3,4,5,6
729 * 0,1,2,3,4,5,6,7
730 */
731static int cfq_get_next_prio_level(struct cfq_data *cfqd)
732{
733 int prio, wrap;
734
735 prio = -1;
736 wrap = 0;
737 do {
738 int p;
739
740 for (p = cfqd->cur_prio; p <= cfqd->cur_end_prio; p++) {
741 if (!list_empty(&cfqd->rr_list[p])) {
742 prio = p;
743 break;
744 }
721 } 745 }
746
747 if (prio != -1)
748 break;
749 cfqd->cur_prio = 0;
750 if (++cfqd->cur_end_prio == CFQ_PRIO_LISTS) {
751 cfqd->cur_end_prio = 0;
752 if (wrap)
753 break;
754 wrap = 1;
755 }
756 } while (1);
757
758 if (unlikely(prio == -1))
759 return -1;
760
761 BUG_ON(prio >= CFQ_PRIO_LISTS);
762
763 list_splice_init(&cfqd->rr_list[prio], &cfqd->cur_rr);
764
765 cfqd->cur_prio = prio + 1;
766 if (cfqd->cur_prio > cfqd->cur_end_prio) {
767 cfqd->cur_end_prio = cfqd->cur_prio;
768 cfqd->cur_prio = 0;
769 }
770 if (cfqd->cur_end_prio == CFQ_PRIO_LISTS) {
771 cfqd->cur_prio = 0;
772 cfqd->cur_end_prio = 0;
722 } 773 }
723 774
724 cfq_update_next_crq(cnext); 775 return prio;
725 cfq_remove_request(q, next); 776}
777
778static void cfq_set_active_queue(struct cfq_data *cfqd)
779{
780 struct cfq_queue *cfqq = NULL;
781
782 /*
783 * if current list is non-empty, grab first entry. if it is empty,
784 * get next prio level and grab first entry then if any are spliced
785 */
786 if (!list_empty(&cfqd->cur_rr) || cfq_get_next_prio_level(cfqd) != -1)
787 cfqq = list_entry_cfqq(cfqd->cur_rr.next);
788
789 /*
790 * if we have idle queues and no rt or be queues had pending
791 * requests, either allow immediate service if the grace period
792 * has passed or arm the idle grace timer
793 */
794 if (!cfqq && !list_empty(&cfqd->idle_rr)) {
795 unsigned long end = cfqd->last_end_request + CFQ_IDLE_GRACE;
796
797 if (time_after_eq(jiffies, end))
798 cfqq = list_entry_cfqq(cfqd->idle_rr.next);
799 else
800 mod_timer(&cfqd->idle_class_timer, end);
801 }
802
803 __cfq_set_active_queue(cfqd, cfqq);
804}
805
806/*
807 * current cfqq expired its slice (or was too idle), select new one
808 */
809static inline void cfq_slice_expired(struct cfq_data *cfqd, int preempted)
810{
811 struct cfq_queue *cfqq = cfqd->active_queue;
812
813 if (cfqq) {
814 unsigned long now = jiffies;
815
816 if (cfqq->wait_request)
817 del_timer(&cfqd->idle_slice_timer);
818
819 if (!preempted && !cfqq->in_flight)
820 cfqq->service_last = now;
821
822 cfqq->must_dispatch = 0;
823 cfqq->wait_request = 0;
824
825 /*
826 * store what was left of this slice, if the queue idled out
827 * or was preempted
828 */
829 if (time_after(now, cfqq->slice_end))
830 cfqq->slice_left = now - cfqq->slice_end;
831 else
832 cfqq->slice_left = 0;
833
834 if (cfqq->on_rr)
835 cfq_resort_rr_list(cfqq, preempted);
836
837 cfqd->active_queue = NULL;
838
839 if (cfqd->active_cic) {
840 put_io_context(cfqd->active_cic->ioc);
841 cfqd->active_cic = NULL;
842 }
843 }
844
845 cfqd->dispatch_slice = 0;
846}
847
848static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq)
849
850{
851 WARN_ON(!RB_EMPTY(&cfqq->sort_list));
852 WARN_ON(cfqq != cfqd->active_queue);
853
854 /*
855 * idle is disabled, either manually or by past process history
856 */
857 if (!cfqd->cfq_slice_idle)
858 return 0;
859 if (!cfqq->idle_window)
860 return 0;
861 /*
862 * task has exited, don't wait
863 */
864 if (cfqd->active_cic && !cfqd->active_cic->ioc->task)
865 return 0;
866
867 cfqq->wait_request = 1;
868 cfqq->must_alloc = 1;
869
870 if (!timer_pending(&cfqd->idle_slice_timer)) {
871 unsigned long slice_left = cfqq->slice_end - 1;
872
873 cfqd->idle_slice_timer.expires = min(jiffies + cfqd->cfq_slice_idle, slice_left);
874 add_timer(&cfqd->idle_slice_timer);
875 }
876
877 return 1;
726} 878}
727 879
728/* 880/*
@@ -738,31 +890,39 @@ static void cfq_dispatch_sort(request_queue_t *q, struct cfq_rq *crq)
738 struct request *__rq; 890 struct request *__rq;
739 sector_t last; 891 sector_t last;
740 892
741 cfq_del_crq_rb(crq);
742 cfq_remove_merge_hints(q, crq);
743 list_del(&crq->request->queuelist); 893 list_del(&crq->request->queuelist);
744 894
745 last = cfqd->last_sector; 895 last = cfqd->last_sector;
746 while ((entry = entry->prev) != head) { 896 list_for_each_entry_reverse(__rq, head, queuelist) {
747 __rq = list_entry_rq(entry); 897 struct cfq_rq *__crq = RQ_DATA(__rq);
748 898
749 if (blk_barrier_rq(crq->request)) 899 if (blk_barrier_rq(__rq))
750 break; 900 break;
751 if (!blk_fs_request(crq->request)) 901 if (!blk_fs_request(__rq))
902 break;
903 if (__crq->requeued)
752 break; 904 break;
753 905
754 if (crq->request->sector > __rq->sector) 906 if (__rq->sector <= crq->request->sector)
755 break; 907 break;
756 if (__rq->sector > last && crq->request->sector < last) { 908 if (__rq->sector > last && crq->request->sector < last) {
757 last = crq->request->sector; 909 last = crq->request->sector + crq->request->nr_sectors;
758 break; 910 break;
759 } 911 }
912 entry = &__rq->queuelist;
760 } 913 }
761 914
762 cfqd->last_sector = last; 915 cfqd->last_sector = last;
916
917 cfqq->next_crq = cfq_find_next_crq(cfqd, cfqq, crq);
918
919 cfq_del_crq_rb(crq);
920 cfq_remove_merge_hints(q, crq);
921
763 crq->in_flight = 1; 922 crq->in_flight = 1;
923 crq->requeued = 0;
764 cfqq->in_flight++; 924 cfqq->in_flight++;
765 list_add(&crq->request->queuelist, entry); 925 list_add_tail(&crq->request->queuelist, entry);
766} 926}
767 927
768/* 928/*
@@ -771,105 +931,176 @@ static void cfq_dispatch_sort(request_queue_t *q, struct cfq_rq *crq)
771static inline struct cfq_rq *cfq_check_fifo(struct cfq_queue *cfqq) 931static inline struct cfq_rq *cfq_check_fifo(struct cfq_queue *cfqq)
772{ 932{
773 struct cfq_data *cfqd = cfqq->cfqd; 933 struct cfq_data *cfqd = cfqq->cfqd;
774 const int reads = !list_empty(&cfqq->fifo[0]); 934 struct request *rq;
775 const int writes = !list_empty(&cfqq->fifo[1]);
776 unsigned long now = jiffies;
777 struct cfq_rq *crq; 935 struct cfq_rq *crq;
778 936
779 if (time_before(now, cfqq->last_fifo_expire + cfqd->cfq_fifo_batch_expire)) 937 if (cfqq->fifo_expire)
780 return NULL; 938 return NULL;
781 939
782 crq = RQ_DATA(list_entry(cfqq->fifo[0].next, struct request, queuelist)); 940 if (!list_empty(&cfqq->fifo)) {
783 if (reads && time_after(now, crq->queue_start + cfqd->cfq_fifo_expire_r)) { 941 int fifo = cfq_cfqq_sync(cfqq);
784 cfqq->last_fifo_expire = now;
785 return crq;
786 }
787 942
788 crq = RQ_DATA(list_entry(cfqq->fifo[1].next, struct request, queuelist)); 943 crq = RQ_DATA(list_entry_fifo(cfqq->fifo.next));
789 if (writes && time_after(now, crq->queue_start + cfqd->cfq_fifo_expire_w)) { 944 rq = crq->request;
790 cfqq->last_fifo_expire = now; 945 if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) {
791 return crq; 946 cfqq->fifo_expire = 1;
947 return crq;
948 }
792 } 949 }
793 950
794 return NULL; 951 return NULL;
795} 952}
796 953
797/* 954/*
798 * dispatch a single request from given queue 955 * Scale schedule slice based on io priority
799 */ 956 */
957static inline int
958cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
959{
960 const int base_slice = cfqd->cfq_slice[cfq_cfqq_sync(cfqq)];
961
962 WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR);
963
964 return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - cfqq->ioprio));
965}
966
800static inline void 967static inline void
801cfq_dispatch_request(request_queue_t *q, struct cfq_data *cfqd, 968cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
802 struct cfq_queue *cfqq)
803{ 969{
804 struct cfq_rq *crq; 970 cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies;
971}
972
973static inline int
974cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
975{
976 const int base_rq = cfqd->cfq_slice_async_rq;
977
978 WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR);
979
980 return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio));
981}
982
983/*
984 * get next queue for service
985 */
986static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd, int force)
987{
988 unsigned long now = jiffies;
989 struct cfq_queue *cfqq;
990
991 cfqq = cfqd->active_queue;
992 if (!cfqq)
993 goto new_queue;
805 994
806 /* 995 /*
807 * follow expired path, else get first next available 996 * slice has expired
808 */ 997 */
809 if ((crq = cfq_check_fifo(cfqq)) == NULL) { 998 if (!cfqq->must_dispatch && time_after(jiffies, cfqq->slice_end))
810 if (cfqd->find_best_crq) 999 goto new_queue;
811 crq = cfqq->next_crq;
812 else
813 crq = rb_entry_crq(rb_first(&cfqq->sort_list));
814 }
815
816 cfqd->last_sector = crq->request->sector + crq->request->nr_sectors;
817 1000
818 /* 1001 /*
819 * finally, insert request into driver list 1002 * if queue has requests, dispatch one. if not, check if
1003 * enough slice is left to wait for one
820 */ 1004 */
821 cfq_dispatch_sort(q, crq); 1005 if (!RB_EMPTY(&cfqq->sort_list))
1006 goto keep_queue;
1007 else if (!force && cfq_cfqq_sync(cfqq) &&
1008 time_before(now, cfqq->slice_end)) {
1009 if (cfq_arm_slice_timer(cfqd, cfqq))
1010 return NULL;
1011 }
1012
1013new_queue:
1014 cfq_slice_expired(cfqd, 0);
1015 cfq_set_active_queue(cfqd);
1016keep_queue:
1017 return cfqd->active_queue;
822} 1018}
823 1019
824static int cfq_dispatch_requests(request_queue_t *q, int max_dispatch) 1020static int
1021__cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq,
1022 int max_dispatch)
825{ 1023{
826 struct cfq_data *cfqd = q->elevator->elevator_data; 1024 int dispatched = 0;
827 struct cfq_queue *cfqq;
828 struct list_head *entry, *tmp;
829 int queued, busy_queues, first_round;
830 1025
831 if (list_empty(&cfqd->rr_list)) 1026 BUG_ON(RB_EMPTY(&cfqq->sort_list));
832 return 0;
833 1027
834 queued = 0; 1028 do {
835 first_round = 1; 1029 struct cfq_rq *crq;
836restart:
837 busy_queues = 0;
838 list_for_each_safe(entry, tmp, &cfqd->rr_list) {
839 cfqq = list_entry_cfqq(entry);
840 1030
841 BUG_ON(RB_EMPTY(&cfqq->sort_list)); 1031 /*
1032 * follow expired path, else get first next available
1033 */
1034 if ((crq = cfq_check_fifo(cfqq)) == NULL)
1035 crq = cfqq->next_crq;
842 1036
843 /* 1037 /*
844 * first round of queueing, only select from queues that 1038 * finally, insert request into driver dispatch list
845 * don't already have io in-flight
846 */ 1039 */
847 if (first_round && cfqq->in_flight) 1040 cfq_dispatch_sort(cfqd->queue, crq);
848 continue;
849 1041
850 cfq_dispatch_request(q, cfqd, cfqq); 1042 cfqd->dispatch_slice++;
1043 dispatched++;
851 1044
852 if (!RB_EMPTY(&cfqq->sort_list)) 1045 if (!cfqd->active_cic) {
853 busy_queues++; 1046 atomic_inc(&crq->io_context->ioc->refcount);
1047 cfqd->active_cic = crq->io_context;
1048 }
854 1049
855 queued++; 1050 if (RB_EMPTY(&cfqq->sort_list))
856 } 1051 break;
1052
1053 } while (dispatched < max_dispatch);
1054
1055 /*
1056 * if slice end isn't set yet, set it. if at least one request was
1057 * sync, use the sync time slice value
1058 */
1059 if (!cfqq->slice_end)
1060 cfq_set_prio_slice(cfqd, cfqq);
1061
1062 /*
1063 * expire an async queue immediately if it has used up its slice. idle
1064 * queue always expire after 1 dispatch round.
1065 */
1066 if ((!cfq_cfqq_sync(cfqq) &&
1067 cfqd->dispatch_slice >= cfq_prio_to_maxrq(cfqd, cfqq)) ||
1068 cfq_class_idle(cfqq))
1069 cfq_slice_expired(cfqd, 0);
1070
1071 return dispatched;
1072}
1073
1074static int
1075cfq_dispatch_requests(request_queue_t *q, int max_dispatch, int force)
1076{
1077 struct cfq_data *cfqd = q->elevator->elevator_data;
1078 struct cfq_queue *cfqq;
857 1079
858 if ((queued < max_dispatch) && (busy_queues || first_round)) { 1080 if (!cfqd->busy_queues)
859 first_round = 0; 1081 return 0;
860 goto restart; 1082
1083 cfqq = cfq_select_queue(cfqd, force);
1084 if (cfqq) {
1085 cfqq->wait_request = 0;
1086 cfqq->must_dispatch = 0;
1087 del_timer(&cfqd->idle_slice_timer);
1088
1089 if (cfq_class_idle(cfqq))
1090 max_dispatch = 1;
1091
1092 return __cfq_dispatch_requests(cfqd, cfqq, max_dispatch);
861 } 1093 }
862 1094
863 return queued; 1095 return 0;
864} 1096}
865 1097
866static inline void cfq_account_dispatch(struct cfq_rq *crq) 1098static inline void cfq_account_dispatch(struct cfq_rq *crq)
867{ 1099{
868 struct cfq_queue *cfqq = crq->cfq_queue; 1100 struct cfq_queue *cfqq = crq->cfq_queue;
869 struct cfq_data *cfqd = cfqq->cfqd; 1101 struct cfq_data *cfqd = cfqq->cfqd;
870 unsigned long now, elapsed;
871 1102
872 if (!blk_fs_request(crq->request)) 1103 if (unlikely(!blk_fs_request(crq->request)))
873 return; 1104 return;
874 1105
875 /* 1106 /*
@@ -879,65 +1110,34 @@ static inline void cfq_account_dispatch(struct cfq_rq *crq)
879 if (crq->accounted) 1110 if (crq->accounted)
880 return; 1111 return;
881 1112
882 now = jiffies;
883 if (cfqq->service_start == ~0UL)
884 cfqq->service_start = now;
885
886 /*
887 * on drives with tagged command queueing, command turn-around time
888 * doesn't necessarily reflect the time spent processing this very
889 * command inside the drive. so do the accounting differently there,
890 * by just sorting on the number of requests
891 */
892 if (cfqd->cfq_tagged) {
893 if (time_after(now, cfqq->service_start + cfq_service)) {
894 cfqq->service_start = now;
895 cfqq->service_used /= 10;
896 }
897
898 cfqq->service_used++;
899 cfq_sort_rr_list(cfqq, 0);
900 }
901
902 elapsed = now - crq->queue_start;
903 if (elapsed > max_elapsed_dispatch)
904 max_elapsed_dispatch = elapsed;
905
906 crq->accounted = 1; 1113 crq->accounted = 1;
907 crq->service_start = now; 1114 cfqd->rq_in_driver++;
908
909 if (++cfqd->rq_in_driver >= CFQ_MAX_TAG && !cfqd->cfq_tagged) {
910 cfqq->cfqd->cfq_tagged = 1;
911 printk("cfq: depth %d reached, tagging now on\n", CFQ_MAX_TAG);
912 }
913} 1115}
914 1116
915static inline void 1117static inline void
916cfq_account_completion(struct cfq_queue *cfqq, struct cfq_rq *crq) 1118cfq_account_completion(struct cfq_queue *cfqq, struct cfq_rq *crq)
917{ 1119{
918 struct cfq_data *cfqd = cfqq->cfqd; 1120 struct cfq_data *cfqd = cfqq->cfqd;
1121 unsigned long now;
919 1122
920 if (!crq->accounted) 1123 if (!crq->accounted)
921 return; 1124 return;
922 1125
1126 now = jiffies;
1127
923 WARN_ON(!cfqd->rq_in_driver); 1128 WARN_ON(!cfqd->rq_in_driver);
924 cfqd->rq_in_driver--; 1129 cfqd->rq_in_driver--;
925 1130
926 if (!cfqd->cfq_tagged) { 1131 if (!cfq_class_idle(cfqq))
927 unsigned long now = jiffies; 1132 cfqd->last_end_request = now;
928 unsigned long duration = now - crq->service_start;
929
930 if (time_after(now, cfqq->service_start + cfq_service)) {
931 cfqq->service_start = now;
932 cfqq->service_used >>= 3;
933 }
934
935 cfqq->service_used += duration;
936 cfq_sort_rr_list(cfqq, 0);
937 1133
938 if (duration > max_elapsed_crq) 1134 if (!cfqq->in_flight && cfqq->on_rr) {
939 max_elapsed_crq = duration; 1135 cfqq->service_last = now;
1136 cfq_resort_rr_list(cfqq, 0);
940 } 1137 }
1138
1139 if (crq->is_sync)
1140 crq->io_context->last_end_request = now;
941} 1141}
942 1142
943static struct request *cfq_next_request(request_queue_t *q) 1143static struct request *cfq_next_request(request_queue_t *q)
@@ -950,7 +1150,15 @@ static struct request *cfq_next_request(request_queue_t *q)
950dispatch: 1150dispatch:
951 rq = list_entry_rq(q->queue_head.next); 1151 rq = list_entry_rq(q->queue_head.next);
952 1152
953 if ((crq = RQ_DATA(rq)) != NULL) { 1153 crq = RQ_DATA(rq);
1154 if (crq) {
1155 /*
1156 * if idle window is disabled, allow queue buildup
1157 */
1158 if (!crq->in_flight && !crq->cfq_queue->idle_window &&
1159 cfqd->rq_in_driver >= cfqd->cfq_max_depth)
1160 return NULL;
1161
954 cfq_remove_merge_hints(q, crq); 1162 cfq_remove_merge_hints(q, crq);
955 cfq_account_dispatch(crq); 1163 cfq_account_dispatch(crq);
956 } 1164 }
@@ -958,7 +1166,7 @@ dispatch:
958 return rq; 1166 return rq;
959 } 1167 }
960 1168
961 if (cfq_dispatch_requests(q, cfqd->cfq_quantum)) 1169 if (cfq_dispatch_requests(q, cfqd->cfq_quantum, 0))
962 goto dispatch; 1170 goto dispatch;
963 1171
964 return NULL; 1172 return NULL;
@@ -972,14 +1180,22 @@ dispatch:
972 */ 1180 */
973static void cfq_put_queue(struct cfq_queue *cfqq) 1181static void cfq_put_queue(struct cfq_queue *cfqq)
974{ 1182{
975 BUG_ON(!atomic_read(&cfqq->ref)); 1183 struct cfq_data *cfqd = cfqq->cfqd;
1184
1185 BUG_ON(atomic_read(&cfqq->ref) <= 0);
976 1186
977 if (!atomic_dec_and_test(&cfqq->ref)) 1187 if (!atomic_dec_and_test(&cfqq->ref))
978 return; 1188 return;
979 1189
980 BUG_ON(rb_first(&cfqq->sort_list)); 1190 BUG_ON(rb_first(&cfqq->sort_list));
1191 BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]);
981 BUG_ON(cfqq->on_rr); 1192 BUG_ON(cfqq->on_rr);
982 1193
1194 if (unlikely(cfqd->active_queue == cfqq)) {
1195 cfq_slice_expired(cfqd, 0);
1196 kblockd_schedule_work(&cfqd->unplug_work);
1197 }
1198
983 cfq_put_cfqd(cfqq->cfqd); 1199 cfq_put_cfqd(cfqq->cfqd);
984 1200
985 /* 1201 /*
@@ -991,7 +1207,7 @@ static void cfq_put_queue(struct cfq_queue *cfqq)
991} 1207}
992 1208
993static inline struct cfq_queue * 1209static inline struct cfq_queue *
994__cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned long key, const int hashval) 1210__cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, const int hashval)
995{ 1211{
996 struct hlist_head *hash_list = &cfqd->cfq_hash[hashval]; 1212 struct hlist_head *hash_list = &cfqd->cfq_hash[hashval];
997 struct hlist_node *entry, *next; 1213 struct hlist_node *entry, *next;
@@ -1007,94 +1223,220 @@ __cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned long key, const int hashval)
1007} 1223}
1008 1224
1009static struct cfq_queue * 1225static struct cfq_queue *
1010cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned long key) 1226cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key)
1011{ 1227{
1012 return __cfq_find_cfq_hash(cfqd, key, hash_long(key, CFQ_QHASH_SHIFT)); 1228 return __cfq_find_cfq_hash(cfqd, key, hash_long(key, CFQ_QHASH_SHIFT));
1013} 1229}
1014 1230
1015static inline void 1231static void cfq_free_io_context(struct cfq_io_context *cic)
1016cfq_rehash_cfqq(struct cfq_data *cfqd, struct cfq_queue **cfqq,
1017 struct cfq_io_context *cic)
1018{ 1232{
1019 unsigned long hashkey = cfq_hash_key(cfqd, current); 1233 struct cfq_io_context *__cic;
1020 unsigned long hashval = hash_long(hashkey, CFQ_QHASH_SHIFT); 1234 struct list_head *entry, *next;
1021 struct cfq_queue *__cfqq;
1022 unsigned long flags;
1023 1235
1024 spin_lock_irqsave(cfqd->queue->queue_lock, flags); 1236 list_for_each_safe(entry, next, &cic->list) {
1025 1237 __cic = list_entry(entry, struct cfq_io_context, list);
1026 hlist_del(&(*cfqq)->cfq_hash); 1238 kmem_cache_free(cfq_ioc_pool, __cic);
1027
1028 __cfqq = __cfq_find_cfq_hash(cfqd, hashkey, hashval);
1029 if (!__cfqq || __cfqq == *cfqq) {
1030 __cfqq = *cfqq;
1031 hlist_add_head(&__cfqq->cfq_hash, &cfqd->cfq_hash[hashval]);
1032 __cfqq->key_type = cfqd->key_type;
1033 } else {
1034 atomic_inc(&__cfqq->ref);
1035 cic->cfqq = __cfqq;
1036 cfq_put_queue(*cfqq);
1037 *cfqq = __cfqq;
1038 } 1239 }
1039 1240
1040 cic->cfqq = __cfqq; 1241 kmem_cache_free(cfq_ioc_pool, cic);
1041 spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
1042} 1242}
1043 1243
1044static void cfq_free_io_context(struct cfq_io_context *cic) 1244/*
1245 * Called with interrupts disabled
1246 */
1247static void cfq_exit_single_io_context(struct cfq_io_context *cic)
1045{ 1248{
1046 kmem_cache_free(cfq_ioc_pool, cic); 1249 struct cfq_data *cfqd = cic->cfqq->cfqd;
1250 request_queue_t *q = cfqd->queue;
1251
1252 WARN_ON(!irqs_disabled());
1253
1254 spin_lock(q->queue_lock);
1255
1256 if (unlikely(cic->cfqq == cfqd->active_queue)) {
1257 cfq_slice_expired(cfqd, 0);
1258 kblockd_schedule_work(&cfqd->unplug_work);
1259 }
1260
1261 cfq_put_queue(cic->cfqq);
1262 cic->cfqq = NULL;
1263 spin_unlock(q->queue_lock);
1047} 1264}
1048 1265
1049/* 1266/*
1050 * locking hierarchy is: io_context lock -> queue locks 1267 * Another task may update the task cic list, if it is doing a queue lookup
1268 * on its behalf. cfq_cic_lock excludes such concurrent updates
1051 */ 1269 */
1052static void cfq_exit_io_context(struct cfq_io_context *cic) 1270static void cfq_exit_io_context(struct cfq_io_context *cic)
1053{ 1271{
1054 struct cfq_queue *cfqq = cic->cfqq; 1272 struct cfq_io_context *__cic;
1055 struct list_head *entry = &cic->list; 1273 struct list_head *entry;
1056 request_queue_t *q;
1057 unsigned long flags; 1274 unsigned long flags;
1058 1275
1276 local_irq_save(flags);
1277
1059 /* 1278 /*
1060 * put the reference this task is holding to the various queues 1279 * put the reference this task is holding to the various queues
1061 */ 1280 */
1062 spin_lock_irqsave(&cic->ioc->lock, flags); 1281 list_for_each(entry, &cic->list) {
1063 while ((entry = cic->list.next) != &cic->list) {
1064 struct cfq_io_context *__cic;
1065
1066 __cic = list_entry(entry, struct cfq_io_context, list); 1282 __cic = list_entry(entry, struct cfq_io_context, list);
1067 list_del(entry); 1283 cfq_exit_single_io_context(__cic);
1068
1069 q = __cic->cfqq->cfqd->queue;
1070 spin_lock(q->queue_lock);
1071 cfq_put_queue(__cic->cfqq);
1072 spin_unlock(q->queue_lock);
1073 } 1284 }
1074 1285
1075 q = cfqq->cfqd->queue; 1286 cfq_exit_single_io_context(cic);
1076 spin_lock(q->queue_lock); 1287 local_irq_restore(flags);
1077 cfq_put_queue(cfqq);
1078 spin_unlock(q->queue_lock);
1079
1080 cic->cfqq = NULL;
1081 spin_unlock_irqrestore(&cic->ioc->lock, flags);
1082} 1288}
1083 1289
1084static struct cfq_io_context *cfq_alloc_io_context(int gfp_flags) 1290static struct cfq_io_context *
1291cfq_alloc_io_context(struct cfq_data *cfqd, int gfp_mask)
1085{ 1292{
1086 struct cfq_io_context *cic = kmem_cache_alloc(cfq_ioc_pool, gfp_flags); 1293 struct cfq_io_context *cic = kmem_cache_alloc(cfq_ioc_pool, gfp_mask);
1087 1294
1088 if (cic) { 1295 if (cic) {
1089 cic->dtor = cfq_free_io_context;
1090 cic->exit = cfq_exit_io_context;
1091 INIT_LIST_HEAD(&cic->list); 1296 INIT_LIST_HEAD(&cic->list);
1092 cic->cfqq = NULL; 1297 cic->cfqq = NULL;
1298 cic->key = NULL;
1299 cic->last_end_request = jiffies;
1300 cic->ttime_total = 0;
1301 cic->ttime_samples = 0;
1302 cic->ttime_mean = 0;
1303 cic->dtor = cfq_free_io_context;
1304 cic->exit = cfq_exit_io_context;
1093 } 1305 }
1094 1306
1095 return cic; 1307 return cic;
1096} 1308}
1097 1309
1310static void cfq_init_prio_data(struct cfq_queue *cfqq)
1311{
1312 struct task_struct *tsk = current;
1313 int ioprio_class;
1314
1315 if (!cfqq->prio_changed)
1316 return;
1317
1318 ioprio_class = IOPRIO_PRIO_CLASS(tsk->ioprio);
1319 switch (ioprio_class) {
1320 default:
1321 printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class);
1322 case IOPRIO_CLASS_NONE:
1323 /*
1324 * no prio set, place us in the middle of the BE classes
1325 */
1326 cfqq->ioprio = task_nice_ioprio(tsk);
1327 cfqq->ioprio_class = IOPRIO_CLASS_BE;
1328 break;
1329 case IOPRIO_CLASS_RT:
1330 cfqq->ioprio = task_ioprio(tsk);
1331 cfqq->ioprio_class = IOPRIO_CLASS_RT;
1332 break;
1333 case IOPRIO_CLASS_BE:
1334 cfqq->ioprio = task_ioprio(tsk);
1335 cfqq->ioprio_class = IOPRIO_CLASS_BE;
1336 break;
1337 case IOPRIO_CLASS_IDLE:
1338 cfqq->ioprio_class = IOPRIO_CLASS_IDLE;
1339 cfqq->ioprio = 7;
1340 cfqq->idle_window = 0;
1341 break;
1342 }
1343
1344 /*
1345 * keep track of original prio settings in case we have to temporarily
1346 * elevate the priority of this queue
1347 */
1348 cfqq->org_ioprio = cfqq->ioprio;
1349 cfqq->org_ioprio_class = cfqq->ioprio_class;
1350
1351 if (cfqq->on_rr)
1352 cfq_resort_rr_list(cfqq, 0);
1353
1354 cfqq->prio_changed = 0;
1355}
1356
1357static inline void changed_ioprio(struct cfq_queue *cfqq)
1358{
1359 if (cfqq) {
1360 struct cfq_data *cfqd = cfqq->cfqd;
1361
1362 spin_lock(cfqd->queue->queue_lock);
1363 cfqq->prio_changed = 1;
1364 cfq_init_prio_data(cfqq);
1365 spin_unlock(cfqd->queue->queue_lock);
1366 }
1367}
1368
1369/*
1370 * callback from sys_ioprio_set, irqs are disabled
1371 */
1372static int cfq_ioc_set_ioprio(struct io_context *ioc, unsigned int ioprio)
1373{
1374 struct cfq_io_context *cic = ioc->cic;
1375
1376 changed_ioprio(cic->cfqq);
1377
1378 list_for_each_entry(cic, &cic->list, list)
1379 changed_ioprio(cic->cfqq);
1380
1381 return 0;
1382}
1383
1384static struct cfq_queue *
1385cfq_get_queue(struct cfq_data *cfqd, unsigned int key, int gfp_mask)
1386{
1387 const int hashval = hash_long(key, CFQ_QHASH_SHIFT);
1388 struct cfq_queue *cfqq, *new_cfqq = NULL;
1389
1390retry:
1391 cfqq = __cfq_find_cfq_hash(cfqd, key, hashval);
1392
1393 if (!cfqq) {
1394 if (new_cfqq) {
1395 cfqq = new_cfqq;
1396 new_cfqq = NULL;
1397 } else if (gfp_mask & __GFP_WAIT) {
1398 spin_unlock_irq(cfqd->queue->queue_lock);
1399 new_cfqq = kmem_cache_alloc(cfq_pool, gfp_mask);
1400 spin_lock_irq(cfqd->queue->queue_lock);
1401 goto retry;
1402 } else {
1403 cfqq = kmem_cache_alloc(cfq_pool, gfp_mask);
1404 if (!cfqq)
1405 goto out;
1406 }
1407
1408 memset(cfqq, 0, sizeof(*cfqq));
1409
1410 INIT_HLIST_NODE(&cfqq->cfq_hash);
1411 INIT_LIST_HEAD(&cfqq->cfq_list);
1412 RB_CLEAR_ROOT(&cfqq->sort_list);
1413 INIT_LIST_HEAD(&cfqq->fifo);
1414
1415 cfqq->key = key;
1416 hlist_add_head(&cfqq->cfq_hash, &cfqd->cfq_hash[hashval]);
1417 atomic_set(&cfqq->ref, 0);
1418 cfqq->cfqd = cfqd;
1419 atomic_inc(&cfqd->ref);
1420 cfqq->service_last = 0;
1421 /*
1422 * set ->slice_left to allow preemption for a new process
1423 */
1424 cfqq->slice_left = 2 * cfqd->cfq_slice_idle;
1425 cfqq->idle_window = 1;
1426 cfqq->ioprio = -1;
1427 cfqq->ioprio_class = -1;
1428 cfqq->prio_changed = 1;
1429 }
1430
1431 if (new_cfqq)
1432 kmem_cache_free(cfq_pool, new_cfqq);
1433
1434 atomic_inc(&cfqq->ref);
1435out:
1436 WARN_ON((gfp_mask & __GFP_WAIT) && !cfqq);
1437 return cfqq;
1438}
1439
1098/* 1440/*
1099 * Setup general io context and cfq io context. There can be several cfq 1441 * Setup general io context and cfq io context. There can be several cfq
1100 * io contexts per general io context, if this process is doing io to more 1442 * io contexts per general io context, if this process is doing io to more
@@ -1102,39 +1444,39 @@ static struct cfq_io_context *cfq_alloc_io_context(int gfp_flags)
1102 * cfqq, so we don't need to worry about it disappearing 1444 * cfqq, so we don't need to worry about it disappearing
1103 */ 1445 */
1104static struct cfq_io_context * 1446static struct cfq_io_context *
1105cfq_get_io_context(struct cfq_queue **cfqq, int gfp_flags) 1447cfq_get_io_context(struct cfq_data *cfqd, pid_t pid, int gfp_mask)
1106{ 1448{
1107 struct cfq_data *cfqd = (*cfqq)->cfqd; 1449 struct io_context *ioc = NULL;
1108 struct cfq_queue *__cfqq = *cfqq;
1109 struct cfq_io_context *cic; 1450 struct cfq_io_context *cic;
1110 struct io_context *ioc;
1111 1451
1112 might_sleep_if(gfp_flags & __GFP_WAIT); 1452 might_sleep_if(gfp_mask & __GFP_WAIT);
1113 1453
1114 ioc = get_io_context(gfp_flags); 1454 ioc = get_io_context(gfp_mask);
1115 if (!ioc) 1455 if (!ioc)
1116 return NULL; 1456 return NULL;
1117 1457
1118 if ((cic = ioc->cic) == NULL) { 1458 if ((cic = ioc->cic) == NULL) {
1119 cic = cfq_alloc_io_context(gfp_flags); 1459 cic = cfq_alloc_io_context(cfqd, gfp_mask);
1120 1460
1121 if (cic == NULL) 1461 if (cic == NULL)
1122 goto err; 1462 goto err;
1123 1463
1464 /*
1465 * manually increment generic io_context usage count, it
1466 * cannot go away since we are already holding one ref to it
1467 */
1124 ioc->cic = cic; 1468 ioc->cic = cic;
1469 ioc->set_ioprio = cfq_ioc_set_ioprio;
1125 cic->ioc = ioc; 1470 cic->ioc = ioc;
1126 cic->cfqq = __cfqq; 1471 cic->key = cfqd;
1127 atomic_inc(&__cfqq->ref); 1472 atomic_inc(&cfqd->ref);
1128 } else { 1473 } else {
1129 struct cfq_io_context *__cic; 1474 struct cfq_io_context *__cic;
1130 unsigned long flags;
1131 1475
1132 /* 1476 /*
1133 * since the first cic on the list is actually the head 1477 * the first cic on the list is actually the head itself
1134 * itself, need to check this here or we'll duplicate an
1135 * cic per ioc for no reason
1136 */ 1478 */
1137 if (cic->cfqq == __cfqq) 1479 if (cic->key == cfqd)
1138 goto out; 1480 goto out;
1139 1481
1140 /* 1482 /*
@@ -1142,152 +1484,259 @@ cfq_get_io_context(struct cfq_queue **cfqq, int gfp_flags)
1142 * should be ok here, the list will usually not be more than 1484 * should be ok here, the list will usually not be more than
1143 * 1 or a few entries long 1485 * 1 or a few entries long
1144 */ 1486 */
1145 spin_lock_irqsave(&ioc->lock, flags);
1146 list_for_each_entry(__cic, &cic->list, list) { 1487 list_for_each_entry(__cic, &cic->list, list) {
1147 /* 1488 /*
1148 * this process is already holding a reference to 1489 * this process is already holding a reference to
1149 * this queue, so no need to get one more 1490 * this queue, so no need to get one more
1150 */ 1491 */
1151 if (__cic->cfqq == __cfqq) { 1492 if (__cic->key == cfqd) {
1152 cic = __cic; 1493 cic = __cic;
1153 spin_unlock_irqrestore(&ioc->lock, flags);
1154 goto out; 1494 goto out;
1155 } 1495 }
1156 } 1496 }
1157 spin_unlock_irqrestore(&ioc->lock, flags);
1158 1497
1159 /* 1498 /*
1160 * nope, process doesn't have a cic assoicated with this 1499 * nope, process doesn't have a cic assoicated with this
1161 * cfqq yet. get a new one and add to list 1500 * cfqq yet. get a new one and add to list
1162 */ 1501 */
1163 __cic = cfq_alloc_io_context(gfp_flags); 1502 __cic = cfq_alloc_io_context(cfqd, gfp_mask);
1164 if (__cic == NULL) 1503 if (__cic == NULL)
1165 goto err; 1504 goto err;
1166 1505
1167 __cic->ioc = ioc; 1506 __cic->ioc = ioc;
1168 __cic->cfqq = __cfqq; 1507 __cic->key = cfqd;
1169 atomic_inc(&__cfqq->ref); 1508 atomic_inc(&cfqd->ref);
1170 spin_lock_irqsave(&ioc->lock, flags);
1171 list_add(&__cic->list, &cic->list); 1509 list_add(&__cic->list, &cic->list);
1172 spin_unlock_irqrestore(&ioc->lock, flags);
1173
1174 cic = __cic; 1510 cic = __cic;
1175 *cfqq = __cfqq;
1176 } 1511 }
1177 1512
1178out: 1513out:
1179 /*
1180 * if key_type has been changed on the fly, we lazily rehash
1181 * each queue at lookup time
1182 */
1183 if ((*cfqq)->key_type != cfqd->key_type)
1184 cfq_rehash_cfqq(cfqd, cfqq, cic);
1185
1186 return cic; 1514 return cic;
1187err: 1515err:
1188 put_io_context(ioc); 1516 put_io_context(ioc);
1189 return NULL; 1517 return NULL;
1190} 1518}
1191 1519
1192static struct cfq_queue * 1520static void
1193__cfq_get_queue(struct cfq_data *cfqd, unsigned long key, int gfp_mask) 1521cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic)
1194{ 1522{
1195 const int hashval = hash_long(key, CFQ_QHASH_SHIFT); 1523 unsigned long elapsed, ttime;
1196 struct cfq_queue *cfqq, *new_cfqq = NULL;
1197
1198retry:
1199 cfqq = __cfq_find_cfq_hash(cfqd, key, hashval);
1200 1524
1201 if (!cfqq) { 1525 /*
1202 if (new_cfqq) { 1526 * if this context already has stuff queued, thinktime is from
1203 cfqq = new_cfqq; 1527 * last queue not last end
1204 new_cfqq = NULL; 1528 */
1205 } else { 1529#if 0
1206 spin_unlock_irq(cfqd->queue->queue_lock); 1530 if (time_after(cic->last_end_request, cic->last_queue))
1207 new_cfqq = kmem_cache_alloc(cfq_pool, gfp_mask); 1531 elapsed = jiffies - cic->last_end_request;
1208 spin_lock_irq(cfqd->queue->queue_lock); 1532 else
1533 elapsed = jiffies - cic->last_queue;
1534#else
1535 elapsed = jiffies - cic->last_end_request;
1536#endif
1209 1537
1210 if (!new_cfqq && !(gfp_mask & __GFP_WAIT)) 1538 ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle);
1211 goto out;
1212 1539
1213 goto retry; 1540 cic->ttime_samples = (7*cic->ttime_samples + 256) / 8;
1214 } 1541 cic->ttime_total = (7*cic->ttime_total + 256*ttime) / 8;
1542 cic->ttime_mean = (cic->ttime_total + 128) / cic->ttime_samples;
1543}
1215 1544
1216 memset(cfqq, 0, sizeof(*cfqq)); 1545#define sample_valid(samples) ((samples) > 80)
1217 1546
1218 INIT_HLIST_NODE(&cfqq->cfq_hash); 1547/*
1219 INIT_LIST_HEAD(&cfqq->cfq_list); 1548 * Disable idle window if the process thinks too long or seeks so much that
1220 RB_CLEAR_ROOT(&cfqq->sort_list); 1549 * it doesn't matter
1221 INIT_LIST_HEAD(&cfqq->fifo[0]); 1550 */
1222 INIT_LIST_HEAD(&cfqq->fifo[1]); 1551static void
1552cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
1553 struct cfq_io_context *cic)
1554{
1555 int enable_idle = cfqq->idle_window;
1223 1556
1224 cfqq->key = key; 1557 if (!cic->ioc->task || !cfqd->cfq_slice_idle)
1225 hlist_add_head(&cfqq->cfq_hash, &cfqd->cfq_hash[hashval]); 1558 enable_idle = 0;
1226 atomic_set(&cfqq->ref, 0); 1559 else if (sample_valid(cic->ttime_samples)) {
1227 cfqq->cfqd = cfqd; 1560 if (cic->ttime_mean > cfqd->cfq_slice_idle)
1228 atomic_inc(&cfqd->ref); 1561 enable_idle = 0;
1229 cfqq->key_type = cfqd->key_type; 1562 else
1230 cfqq->service_start = ~0UL; 1563 enable_idle = 1;
1231 } 1564 }
1232 1565
1233 if (new_cfqq) 1566 cfqq->idle_window = enable_idle;
1234 kmem_cache_free(cfq_pool, new_cfqq); 1567}
1235 1568
1236 atomic_inc(&cfqq->ref); 1569
1237out: 1570/*
1238 WARN_ON((gfp_mask & __GFP_WAIT) && !cfqq); 1571 * Check if new_cfqq should preempt the currently active queue. Return 0 for
1239 return cfqq; 1572 * no or if we aren't sure, a 1 will cause a preempt.
1573 */
1574static int
1575cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
1576 struct cfq_rq *crq)
1577{
1578 struct cfq_queue *cfqq = cfqd->active_queue;
1579
1580 if (cfq_class_idle(new_cfqq))
1581 return 0;
1582
1583 if (!cfqq)
1584 return 1;
1585
1586 if (cfq_class_idle(cfqq))
1587 return 1;
1588 if (!new_cfqq->wait_request)
1589 return 0;
1590 /*
1591 * if it doesn't have slice left, forget it
1592 */
1593 if (new_cfqq->slice_left < cfqd->cfq_slice_idle)
1594 return 0;
1595 if (crq->is_sync && !cfq_cfqq_sync(cfqq))
1596 return 1;
1597
1598 return 0;
1599}
1600
1601/*
1602 * cfqq preempts the active queue. if we allowed preempt with no slice left,
1603 * let it have half of its nominal slice.
1604 */
1605static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
1606{
1607 struct cfq_queue *__cfqq, *next;
1608
1609 list_for_each_entry_safe(__cfqq, next, &cfqd->cur_rr, cfq_list)
1610 cfq_resort_rr_list(__cfqq, 1);
1611
1612 if (!cfqq->slice_left)
1613 cfqq->slice_left = cfq_prio_to_slice(cfqd, cfqq) / 2;
1614
1615 cfqq->slice_end = cfqq->slice_left + jiffies;
1616 cfq_slice_expired(cfqd, 1);
1617 __cfq_set_active_queue(cfqd, cfqq);
1240} 1618}
1241 1619
1242static void cfq_enqueue(struct cfq_data *cfqd, struct cfq_rq *crq) 1620/*
1621 * should really be a ll_rw_blk.c helper
1622 */
1623static void cfq_start_queueing(struct cfq_data *cfqd, struct cfq_queue *cfqq)
1243{ 1624{
1244 crq->is_sync = 0; 1625 request_queue_t *q = cfqd->queue;
1245 if (rq_data_dir(crq->request) == READ || current->flags & PF_SYNCWRITE) 1626
1246 crq->is_sync = 1; 1627 if (!blk_queue_plugged(q))
1628 q->request_fn(q);
1629 else
1630 __generic_unplug_device(q);
1631}
1632
1633/*
1634 * Called when a new fs request (crq) is added (to cfqq). Check if there's
1635 * something we should do about it
1636 */
1637static void
1638cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
1639 struct cfq_rq *crq)
1640{
1641 const int sync = crq->is_sync;
1642
1643 cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq);
1644
1645 if (sync) {
1646 struct cfq_io_context *cic = crq->io_context;
1647
1648 cfq_update_io_thinktime(cfqd, cic);
1649 cfq_update_idle_window(cfqd, cfqq, cic);
1650
1651 cic->last_queue = jiffies;
1652 }
1653
1654 if (cfqq == cfqd->active_queue) {
1655 /*
1656 * if we are waiting for a request for this queue, let it rip
1657 * immediately and flag that we must not expire this queue
1658 * just now
1659 */
1660 if (cfqq->wait_request) {
1661 cfqq->must_dispatch = 1;
1662 del_timer(&cfqd->idle_slice_timer);
1663 cfq_start_queueing(cfqd, cfqq);
1664 }
1665 } else if (cfq_should_preempt(cfqd, cfqq, crq)) {
1666 /*
1667 * not the active queue - expire current slice if it is
1668 * idle and has expired it's mean thinktime or this new queue
1669 * has some old slice time left and is of higher priority
1670 */
1671 cfq_preempt_queue(cfqd, cfqq);
1672 cfqq->must_dispatch = 1;
1673 cfq_start_queueing(cfqd, cfqq);
1674 }
1675}
1676
1677static void cfq_enqueue(struct cfq_data *cfqd, struct request *rq)
1678{
1679 struct cfq_rq *crq = RQ_DATA(rq);
1680 struct cfq_queue *cfqq = crq->cfq_queue;
1681
1682 cfq_init_prio_data(cfqq);
1247 1683
1248 cfq_add_crq_rb(crq); 1684 cfq_add_crq_rb(crq);
1249 crq->queue_start = jiffies;
1250 1685
1251 list_add_tail(&crq->request->queuelist, &crq->cfq_queue->fifo[crq->is_sync]); 1686 list_add_tail(&rq->queuelist, &cfqq->fifo);
1687
1688 if (rq_mergeable(rq)) {
1689 cfq_add_crq_hash(cfqd, crq);
1690
1691 if (!cfqd->queue->last_merge)
1692 cfqd->queue->last_merge = rq;
1693 }
1694
1695 cfq_crq_enqueued(cfqd, cfqq, crq);
1252} 1696}
1253 1697
1254static void 1698static void
1255cfq_insert_request(request_queue_t *q, struct request *rq, int where) 1699cfq_insert_request(request_queue_t *q, struct request *rq, int where)
1256{ 1700{
1257 struct cfq_data *cfqd = q->elevator->elevator_data; 1701 struct cfq_data *cfqd = q->elevator->elevator_data;
1258 struct cfq_rq *crq = RQ_DATA(rq);
1259 1702
1260 switch (where) { 1703 switch (where) {
1261 case ELEVATOR_INSERT_BACK: 1704 case ELEVATOR_INSERT_BACK:
1262 while (cfq_dispatch_requests(q, cfqd->cfq_quantum)) 1705 while (cfq_dispatch_requests(q, INT_MAX, 1))
1263 ; 1706 ;
1264 list_add_tail(&rq->queuelist, &q->queue_head); 1707 list_add_tail(&rq->queuelist, &q->queue_head);
1708 /*
1709 * If we were idling with pending requests on
1710 * inactive cfqqs, force dispatching will
1711 * remove the idle timer and the queue won't
1712 * be kicked by __make_request() afterward.
1713 * Kick it here.
1714 */
1715 kblockd_schedule_work(&cfqd->unplug_work);
1265 break; 1716 break;
1266 case ELEVATOR_INSERT_FRONT: 1717 case ELEVATOR_INSERT_FRONT:
1267 list_add(&rq->queuelist, &q->queue_head); 1718 list_add(&rq->queuelist, &q->queue_head);
1268 break; 1719 break;
1269 case ELEVATOR_INSERT_SORT: 1720 case ELEVATOR_INSERT_SORT:
1270 BUG_ON(!blk_fs_request(rq)); 1721 BUG_ON(!blk_fs_request(rq));
1271 cfq_enqueue(cfqd, crq); 1722 cfq_enqueue(cfqd, rq);
1272 break; 1723 break;
1273 default: 1724 default:
1274 printk("%s: bad insert point %d\n", __FUNCTION__,where); 1725 printk("%s: bad insert point %d\n", __FUNCTION__,where);
1275 return; 1726 return;
1276 } 1727 }
1728}
1277 1729
1278 if (rq_mergeable(rq)) { 1730static inline int cfq_pending_requests(struct cfq_data *cfqd)
1279 cfq_add_crq_hash(cfqd, crq); 1731{
1280 1732 return !list_empty(&cfqd->queue->queue_head) || cfqd->busy_queues;
1281 if (!q->last_merge)
1282 q->last_merge = rq;
1283 }
1284} 1733}
1285 1734
1286static int cfq_queue_empty(request_queue_t *q) 1735static int cfq_queue_empty(request_queue_t *q)
1287{ 1736{
1288 struct cfq_data *cfqd = q->elevator->elevator_data; 1737 struct cfq_data *cfqd = q->elevator->elevator_data;
1289 1738
1290 return list_empty(&q->queue_head) && list_empty(&cfqd->rr_list); 1739 return !cfq_pending_requests(cfqd);
1291} 1740}
1292 1741
1293static void cfq_completed_request(request_queue_t *q, struct request *rq) 1742static void cfq_completed_request(request_queue_t *q, struct request *rq)
@@ -1332,51 +1781,132 @@ cfq_latter_request(request_queue_t *q, struct request *rq)
1332 return NULL; 1781 return NULL;
1333} 1782}
1334 1783
1335static int cfq_may_queue(request_queue_t *q, int rw) 1784/*
1785 * we temporarily boost lower priority queues if they are holding fs exclusive
1786 * resources. they are boosted to normal prio (CLASS_BE/4)
1787 */
1788static void cfq_prio_boost(struct cfq_queue *cfqq)
1336{ 1789{
1337 struct cfq_data *cfqd = q->elevator->elevator_data; 1790 const int ioprio_class = cfqq->ioprio_class;
1338 struct cfq_queue *cfqq; 1791 const int ioprio = cfqq->ioprio;
1339 int ret = ELV_MQUEUE_MAY;
1340 1792
1341 if (current->flags & PF_MEMALLOC) 1793 if (has_fs_excl()) {
1342 return ELV_MQUEUE_MAY; 1794 /*
1795 * boost idle prio on transactions that would lock out other
1796 * users of the filesystem
1797 */
1798 if (cfq_class_idle(cfqq))
1799 cfqq->ioprio_class = IOPRIO_CLASS_BE;
1800 if (cfqq->ioprio > IOPRIO_NORM)
1801 cfqq->ioprio = IOPRIO_NORM;
1802 } else {
1803 /*
1804 * check if we need to unboost the queue
1805 */
1806 if (cfqq->ioprio_class != cfqq->org_ioprio_class)
1807 cfqq->ioprio_class = cfqq->org_ioprio_class;
1808 if (cfqq->ioprio != cfqq->org_ioprio)
1809 cfqq->ioprio = cfqq->org_ioprio;
1810 }
1343 1811
1344 cfqq = cfq_find_cfq_hash(cfqd, cfq_hash_key(cfqd, current)); 1812 /*
1345 if (cfqq) { 1813 * refile between round-robin lists if we moved the priority class
1346 int limit = cfqd->max_queued; 1814 */
1815 if ((ioprio_class != cfqq->ioprio_class || ioprio != cfqq->ioprio) &&
1816 cfqq->on_rr)
1817 cfq_resort_rr_list(cfqq, 0);
1818}
1347 1819
1348 if (cfqq->allocated[rw] < cfqd->cfq_queued) 1820static inline pid_t cfq_queue_pid(struct task_struct *task, int rw)
1349 return ELV_MQUEUE_MUST; 1821{
1822 if (rw == READ || process_sync(task))
1823 return task->pid;
1350 1824
1351 if (cfqd->busy_queues) 1825 return CFQ_KEY_ASYNC;
1352 limit = q->nr_requests / cfqd->busy_queues; 1826}
1353 1827
1354 if (limit < cfqd->cfq_queued) 1828static inline int
1355 limit = cfqd->cfq_queued; 1829__cfq_may_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq,
1356 else if (limit > cfqd->max_queued) 1830 struct task_struct *task, int rw)
1357 limit = cfqd->max_queued; 1831{
1832 if (cfqq->wait_request && cfqq->must_alloc)
1833 return ELV_MQUEUE_MUST;
1358 1834
1359 if (cfqq->allocated[rw] >= limit) { 1835 return ELV_MQUEUE_MAY;
1360 if (limit > cfqq->alloc_limit[rw]) 1836#if 0
1361 cfqq->alloc_limit[rw] = limit; 1837 if (!cfqq || task->flags & PF_MEMALLOC)
1838 return ELV_MQUEUE_MAY;
1839 if (!cfqq->allocated[rw] || cfqq->must_alloc) {
1840 if (cfqq->wait_request)
1841 return ELV_MQUEUE_MUST;
1362 1842
1363 ret = ELV_MQUEUE_NO; 1843 /*
1844 * only allow 1 ELV_MQUEUE_MUST per slice, otherwise we
1845 * can quickly flood the queue with writes from a single task
1846 */
1847 if (rw == READ || !cfqq->must_alloc_slice) {
1848 cfqq->must_alloc_slice = 1;
1849 return ELV_MQUEUE_MUST;
1364 } 1850 }
1851
1852 return ELV_MQUEUE_MAY;
1365 } 1853 }
1854 if (cfq_class_idle(cfqq))
1855 return ELV_MQUEUE_NO;
1856 if (cfqq->allocated[rw] >= cfqd->max_queued) {
1857 struct io_context *ioc = get_io_context(GFP_ATOMIC);
1858 int ret = ELV_MQUEUE_NO;
1366 1859
1367 return ret; 1860 if (ioc && ioc->nr_batch_requests)
1861 ret = ELV_MQUEUE_MAY;
1862
1863 put_io_context(ioc);
1864 return ret;
1865 }
1866
1867 return ELV_MQUEUE_MAY;
1868#endif
1869}
1870
1871static int cfq_may_queue(request_queue_t *q, int rw, struct bio *bio)
1872{
1873 struct cfq_data *cfqd = q->elevator->elevator_data;
1874 struct task_struct *tsk = current;
1875 struct cfq_queue *cfqq;
1876
1877 /*
1878 * don't force setup of a queue from here, as a call to may_queue
1879 * does not necessarily imply that a request actually will be queued.
1880 * so just lookup a possibly existing queue, or return 'may queue'
1881 * if that fails
1882 */
1883 cfqq = cfq_find_cfq_hash(cfqd, cfq_queue_pid(tsk, rw));
1884 if (cfqq) {
1885 cfq_init_prio_data(cfqq);
1886 cfq_prio_boost(cfqq);
1887
1888 return __cfq_may_queue(cfqd, cfqq, tsk, rw);
1889 }
1890
1891 return ELV_MQUEUE_MAY;
1368} 1892}
1369 1893
1370static void cfq_check_waiters(request_queue_t *q, struct cfq_queue *cfqq) 1894static void cfq_check_waiters(request_queue_t *q, struct cfq_queue *cfqq)
1371{ 1895{
1896 struct cfq_data *cfqd = q->elevator->elevator_data;
1372 struct request_list *rl = &q->rq; 1897 struct request_list *rl = &q->rq;
1373 const int write = waitqueue_active(&rl->wait[WRITE]);
1374 const int read = waitqueue_active(&rl->wait[READ]);
1375 1898
1376 if (read && cfqq->allocated[READ] < cfqq->alloc_limit[READ]) 1899 if (cfqq->allocated[READ] <= cfqd->max_queued || cfqd->rq_starved) {
1377 wake_up(&rl->wait[READ]); 1900 smp_mb();
1378 if (write && cfqq->allocated[WRITE] < cfqq->alloc_limit[WRITE]) 1901 if (waitqueue_active(&rl->wait[READ]))
1379 wake_up(&rl->wait[WRITE]); 1902 wake_up(&rl->wait[READ]);
1903 }
1904
1905 if (cfqq->allocated[WRITE] <= cfqd->max_queued || cfqd->rq_starved) {
1906 smp_mb();
1907 if (waitqueue_active(&rl->wait[WRITE]))
1908 wake_up(&rl->wait[WRITE]);
1909 }
1380} 1910}
1381 1911
1382/* 1912/*
@@ -1389,69 +1919,59 @@ static void cfq_put_request(request_queue_t *q, struct request *rq)
1389 1919
1390 if (crq) { 1920 if (crq) {
1391 struct cfq_queue *cfqq = crq->cfq_queue; 1921 struct cfq_queue *cfqq = crq->cfq_queue;
1922 const int rw = rq_data_dir(rq);
1392 1923
1393 BUG_ON(q->last_merge == rq); 1924 BUG_ON(!cfqq->allocated[rw]);
1394 BUG_ON(!hlist_unhashed(&crq->hash)); 1925 cfqq->allocated[rw]--;
1395
1396 if (crq->io_context)
1397 put_io_context(crq->io_context->ioc);
1398 1926
1399 BUG_ON(!cfqq->allocated[crq->is_write]); 1927 put_io_context(crq->io_context->ioc);
1400 cfqq->allocated[crq->is_write]--;
1401 1928
1402 mempool_free(crq, cfqd->crq_pool); 1929 mempool_free(crq, cfqd->crq_pool);
1403 rq->elevator_private = NULL; 1930 rq->elevator_private = NULL;
1404 1931
1405 smp_mb();
1406 cfq_check_waiters(q, cfqq); 1932 cfq_check_waiters(q, cfqq);
1407 cfq_put_queue(cfqq); 1933 cfq_put_queue(cfqq);
1408 } 1934 }
1409} 1935}
1410 1936
1411/* 1937/*
1412 * Allocate cfq data structures associated with this request. A queue and 1938 * Allocate cfq data structures associated with this request.
1413 */ 1939 */
1414static int cfq_set_request(request_queue_t *q, struct request *rq, int gfp_mask) 1940static int
1941cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio,
1942 int gfp_mask)
1415{ 1943{
1416 struct cfq_data *cfqd = q->elevator->elevator_data; 1944 struct cfq_data *cfqd = q->elevator->elevator_data;
1417 struct cfq_io_context *cic; 1945 struct cfq_io_context *cic;
1418 const int rw = rq_data_dir(rq); 1946 const int rw = rq_data_dir(rq);
1419 struct cfq_queue *cfqq, *saved_cfqq; 1947 struct cfq_queue *cfqq;
1420 struct cfq_rq *crq; 1948 struct cfq_rq *crq;
1421 unsigned long flags; 1949 unsigned long flags;
1422 1950
1423 might_sleep_if(gfp_mask & __GFP_WAIT); 1951 might_sleep_if(gfp_mask & __GFP_WAIT);
1424 1952
1953 cic = cfq_get_io_context(cfqd, cfq_queue_pid(current, rw), gfp_mask);
1954
1425 spin_lock_irqsave(q->queue_lock, flags); 1955 spin_lock_irqsave(q->queue_lock, flags);
1426 1956
1427 cfqq = __cfq_get_queue(cfqd, cfq_hash_key(cfqd, current), gfp_mask); 1957 if (!cic)
1428 if (!cfqq) 1958 goto queue_fail;
1429 goto out_lock; 1959
1960 if (!cic->cfqq) {
1961 cfqq = cfq_get_queue(cfqd, current->pid, gfp_mask);
1962 if (!cfqq)
1963 goto queue_fail;
1430 1964
1431repeat: 1965 cic->cfqq = cfqq;
1432 if (cfqq->allocated[rw] >= cfqd->max_queued) 1966 } else
1433 goto out_lock; 1967 cfqq = cic->cfqq;
1434 1968
1435 cfqq->allocated[rw]++; 1969 cfqq->allocated[rw]++;
1970 cfqq->must_alloc = 0;
1971 cfqd->rq_starved = 0;
1972 atomic_inc(&cfqq->ref);
1436 spin_unlock_irqrestore(q->queue_lock, flags); 1973 spin_unlock_irqrestore(q->queue_lock, flags);
1437 1974
1438 /*
1439 * if hashing type has changed, the cfq_queue might change here.
1440 */
1441 saved_cfqq = cfqq;
1442 cic = cfq_get_io_context(&cfqq, gfp_mask);
1443 if (!cic)
1444 goto err;
1445
1446 /*
1447 * repeat allocation checks on queue change
1448 */
1449 if (unlikely(saved_cfqq != cfqq)) {
1450 spin_lock_irqsave(q->queue_lock, flags);
1451 saved_cfqq->allocated[rw]--;
1452 goto repeat;
1453 }
1454
1455 crq = mempool_alloc(cfqd->crq_pool, gfp_mask); 1975 crq = mempool_alloc(cfqd->crq_pool, gfp_mask);
1456 if (crq) { 1976 if (crq) {
1457 RB_CLEAR(&crq->rb_node); 1977 RB_CLEAR(&crq->rb_node);
@@ -1460,24 +1980,130 @@ repeat:
1460 INIT_HLIST_NODE(&crq->hash); 1980 INIT_HLIST_NODE(&crq->hash);
1461 crq->cfq_queue = cfqq; 1981 crq->cfq_queue = cfqq;
1462 crq->io_context = cic; 1982 crq->io_context = cic;
1463 crq->service_start = crq->queue_start = 0; 1983 crq->in_flight = crq->accounted = 0;
1464 crq->in_flight = crq->accounted = crq->is_sync = 0; 1984 crq->is_sync = (rw == READ || process_sync(current));
1465 crq->is_write = rw; 1985 crq->requeued = 0;
1466 rq->elevator_private = crq; 1986 rq->elevator_private = crq;
1467 cfqq->alloc_limit[rw] = 0;
1468 return 0; 1987 return 0;
1469 } 1988 }
1470 1989
1471 put_io_context(cic->ioc);
1472err:
1473 spin_lock_irqsave(q->queue_lock, flags); 1990 spin_lock_irqsave(q->queue_lock, flags);
1474 cfqq->allocated[rw]--; 1991 cfqq->allocated[rw]--;
1992 if (!(cfqq->allocated[0] + cfqq->allocated[1]))
1993 cfqq->must_alloc = 1;
1475 cfq_put_queue(cfqq); 1994 cfq_put_queue(cfqq);
1476out_lock: 1995queue_fail:
1996 if (cic)
1997 put_io_context(cic->ioc);
1998 /*
1999 * mark us rq allocation starved. we need to kickstart the process
2000 * ourselves if there are no pending requests that can do it for us.
2001 * that would be an extremely rare OOM situation
2002 */
2003 cfqd->rq_starved = 1;
2004 kblockd_schedule_work(&cfqd->unplug_work);
1477 spin_unlock_irqrestore(q->queue_lock, flags); 2005 spin_unlock_irqrestore(q->queue_lock, flags);
1478 return 1; 2006 return 1;
1479} 2007}
1480 2008
2009static void cfq_kick_queue(void *data)
2010{
2011 request_queue_t *q = data;
2012 struct cfq_data *cfqd = q->elevator->elevator_data;
2013 unsigned long flags;
2014
2015 spin_lock_irqsave(q->queue_lock, flags);
2016
2017 if (cfqd->rq_starved) {
2018 struct request_list *rl = &q->rq;
2019
2020 /*
2021 * we aren't guaranteed to get a request after this, but we
2022 * have to be opportunistic
2023 */
2024 smp_mb();
2025 if (waitqueue_active(&rl->wait[READ]))
2026 wake_up(&rl->wait[READ]);
2027 if (waitqueue_active(&rl->wait[WRITE]))
2028 wake_up(&rl->wait[WRITE]);
2029 }
2030
2031 blk_remove_plug(q);
2032 q->request_fn(q);
2033 spin_unlock_irqrestore(q->queue_lock, flags);
2034}
2035
2036/*
2037 * Timer running if the active_queue is currently idling inside its time slice
2038 */
2039static void cfq_idle_slice_timer(unsigned long data)
2040{
2041 struct cfq_data *cfqd = (struct cfq_data *) data;
2042 struct cfq_queue *cfqq;
2043 unsigned long flags;
2044
2045 spin_lock_irqsave(cfqd->queue->queue_lock, flags);
2046
2047 if ((cfqq = cfqd->active_queue) != NULL) {
2048 unsigned long now = jiffies;
2049
2050 /*
2051 * expired
2052 */
2053 if (time_after(now, cfqq->slice_end))
2054 goto expire;
2055
2056 /*
2057 * only expire and reinvoke request handler, if there are
2058 * other queues with pending requests
2059 */
2060 if (!cfq_pending_requests(cfqd)) {
2061 cfqd->idle_slice_timer.expires = min(now + cfqd->cfq_slice_idle, cfqq->slice_end);
2062 add_timer(&cfqd->idle_slice_timer);
2063 goto out_cont;
2064 }
2065
2066 /*
2067 * not expired and it has a request pending, let it dispatch
2068 */
2069 if (!RB_EMPTY(&cfqq->sort_list)) {
2070 cfqq->must_dispatch = 1;
2071 goto out_kick;
2072 }
2073 }
2074expire:
2075 cfq_slice_expired(cfqd, 0);
2076out_kick:
2077 if (cfq_pending_requests(cfqd))
2078 kblockd_schedule_work(&cfqd->unplug_work);
2079out_cont:
2080 spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
2081}
2082
2083/*
2084 * Timer running if an idle class queue is waiting for service
2085 */
2086static void cfq_idle_class_timer(unsigned long data)
2087{
2088 struct cfq_data *cfqd = (struct cfq_data *) data;
2089 unsigned long flags, end;
2090
2091 spin_lock_irqsave(cfqd->queue->queue_lock, flags);
2092
2093 /*
2094 * race with a non-idle queue, reset timer
2095 */
2096 end = cfqd->last_end_request + CFQ_IDLE_GRACE;
2097 if (!time_after_eq(jiffies, end)) {
2098 cfqd->idle_class_timer.expires = end;
2099 add_timer(&cfqd->idle_class_timer);
2100 } else
2101 kblockd_schedule_work(&cfqd->unplug_work);
2102
2103 spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
2104}
2105
2106
1481static void cfq_put_cfqd(struct cfq_data *cfqd) 2107static void cfq_put_cfqd(struct cfq_data *cfqd)
1482{ 2108{
1483 request_queue_t *q = cfqd->queue; 2109 request_queue_t *q = cfqd->queue;
@@ -1485,6 +2111,8 @@ static void cfq_put_cfqd(struct cfq_data *cfqd)
1485 if (!atomic_dec_and_test(&cfqd->ref)) 2111 if (!atomic_dec_and_test(&cfqd->ref))
1486 return; 2112 return;
1487 2113
2114 blk_sync_queue(q);
2115
1488 blk_put_queue(q); 2116 blk_put_queue(q);
1489 2117
1490 mempool_destroy(cfqd->crq_pool); 2118 mempool_destroy(cfqd->crq_pool);
@@ -1495,7 +2123,11 @@ static void cfq_put_cfqd(struct cfq_data *cfqd)
1495 2123
1496static void cfq_exit_queue(elevator_t *e) 2124static void cfq_exit_queue(elevator_t *e)
1497{ 2125{
1498 cfq_put_cfqd(e->elevator_data); 2126 struct cfq_data *cfqd = e->elevator_data;
2127
2128 del_timer_sync(&cfqd->idle_slice_timer);
2129 del_timer_sync(&cfqd->idle_class_timer);
2130 cfq_put_cfqd(cfqd);
1499} 2131}
1500 2132
1501static int cfq_init_queue(request_queue_t *q, elevator_t *e) 2133static int cfq_init_queue(request_queue_t *q, elevator_t *e)
@@ -1508,7 +2140,13 @@ static int cfq_init_queue(request_queue_t *q, elevator_t *e)
1508 return -ENOMEM; 2140 return -ENOMEM;
1509 2141
1510 memset(cfqd, 0, sizeof(*cfqd)); 2142 memset(cfqd, 0, sizeof(*cfqd));
1511 INIT_LIST_HEAD(&cfqd->rr_list); 2143
2144 for (i = 0; i < CFQ_PRIO_LISTS; i++)
2145 INIT_LIST_HEAD(&cfqd->rr_list[i]);
2146
2147 INIT_LIST_HEAD(&cfqd->busy_rr);
2148 INIT_LIST_HEAD(&cfqd->cur_rr);
2149 INIT_LIST_HEAD(&cfqd->idle_rr);
1512 INIT_LIST_HEAD(&cfqd->empty_list); 2150 INIT_LIST_HEAD(&cfqd->empty_list);
1513 2151
1514 cfqd->crq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_MHASH_ENTRIES, GFP_KERNEL); 2152 cfqd->crq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_MHASH_ENTRIES, GFP_KERNEL);
@@ -1533,25 +2171,32 @@ static int cfq_init_queue(request_queue_t *q, elevator_t *e)
1533 cfqd->queue = q; 2171 cfqd->queue = q;
1534 atomic_inc(&q->refcnt); 2172 atomic_inc(&q->refcnt);
1535 2173
1536 /* 2174 cfqd->max_queued = q->nr_requests / 4;
1537 * just set it to some high value, we want anyone to be able to queue
1538 * some requests. fairness is handled differently
1539 */
1540 q->nr_requests = 1024;
1541 cfqd->max_queued = q->nr_requests / 16;
1542 q->nr_batching = cfq_queued; 2175 q->nr_batching = cfq_queued;
1543 cfqd->key_type = CFQ_KEY_TGID; 2176
1544 cfqd->find_best_crq = 1; 2177 init_timer(&cfqd->idle_slice_timer);
2178 cfqd->idle_slice_timer.function = cfq_idle_slice_timer;
2179 cfqd->idle_slice_timer.data = (unsigned long) cfqd;
2180
2181 init_timer(&cfqd->idle_class_timer);
2182 cfqd->idle_class_timer.function = cfq_idle_class_timer;
2183 cfqd->idle_class_timer.data = (unsigned long) cfqd;
2184
2185 INIT_WORK(&cfqd->unplug_work, cfq_kick_queue, q);
2186
1545 atomic_set(&cfqd->ref, 1); 2187 atomic_set(&cfqd->ref, 1);
1546 2188
1547 cfqd->cfq_queued = cfq_queued; 2189 cfqd->cfq_queued = cfq_queued;
1548 cfqd->cfq_quantum = cfq_quantum; 2190 cfqd->cfq_quantum = cfq_quantum;
1549 cfqd->cfq_fifo_expire_r = cfq_fifo_expire_r; 2191 cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0];
1550 cfqd->cfq_fifo_expire_w = cfq_fifo_expire_w; 2192 cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1];
1551 cfqd->cfq_fifo_batch_expire = cfq_fifo_rate;
1552 cfqd->cfq_back_max = cfq_back_max; 2193 cfqd->cfq_back_max = cfq_back_max;
1553 cfqd->cfq_back_penalty = cfq_back_penalty; 2194 cfqd->cfq_back_penalty = cfq_back_penalty;
1554 2195 cfqd->cfq_slice[0] = cfq_slice_async;
2196 cfqd->cfq_slice[1] = cfq_slice_sync;
2197 cfqd->cfq_slice_async_rq = cfq_slice_async_rq;
2198 cfqd->cfq_slice_idle = cfq_slice_idle;
2199 cfqd->cfq_max_depth = cfq_max_depth;
1555 return 0; 2200 return 0;
1556out_crqpool: 2201out_crqpool:
1557 kfree(cfqd->cfq_hash); 2202 kfree(cfqd->cfq_hash);
@@ -1595,7 +2240,6 @@ fail:
1595 return -ENOMEM; 2240 return -ENOMEM;
1596} 2241}
1597 2242
1598
1599/* 2243/*
1600 * sysfs parts below --> 2244 * sysfs parts below -->
1601 */ 2245 */
@@ -1620,45 +2264,6 @@ cfq_var_store(unsigned int *var, const char *page, size_t count)
1620 return count; 2264 return count;
1621} 2265}
1622 2266
1623static ssize_t
1624cfq_clear_elapsed(struct cfq_data *cfqd, const char *page, size_t count)
1625{
1626 max_elapsed_dispatch = max_elapsed_crq = 0;
1627 return count;
1628}
1629
1630static ssize_t
1631cfq_set_key_type(struct cfq_data *cfqd, const char *page, size_t count)
1632{
1633 spin_lock_irq(cfqd->queue->queue_lock);
1634 if (!strncmp(page, "pgid", 4))
1635 cfqd->key_type = CFQ_KEY_PGID;
1636 else if (!strncmp(page, "tgid", 4))
1637 cfqd->key_type = CFQ_KEY_TGID;
1638 else if (!strncmp(page, "uid", 3))
1639 cfqd->key_type = CFQ_KEY_UID;
1640 else if (!strncmp(page, "gid", 3))
1641 cfqd->key_type = CFQ_KEY_GID;
1642 spin_unlock_irq(cfqd->queue->queue_lock);
1643 return count;
1644}
1645
1646static ssize_t
1647cfq_read_key_type(struct cfq_data *cfqd, char *page)
1648{
1649 ssize_t len = 0;
1650 int i;
1651
1652 for (i = CFQ_KEY_PGID; i < CFQ_KEY_LAST; i++) {
1653 if (cfqd->key_type == i)
1654 len += sprintf(page+len, "[%s] ", cfq_key_types[i]);
1655 else
1656 len += sprintf(page+len, "%s ", cfq_key_types[i]);
1657 }
1658 len += sprintf(page+len, "\n");
1659 return len;
1660}
1661
1662#define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ 2267#define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \
1663static ssize_t __FUNC(struct cfq_data *cfqd, char *page) \ 2268static ssize_t __FUNC(struct cfq_data *cfqd, char *page) \
1664{ \ 2269{ \
@@ -1669,12 +2274,15 @@ static ssize_t __FUNC(struct cfq_data *cfqd, char *page) \
1669} 2274}
1670SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); 2275SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0);
1671SHOW_FUNCTION(cfq_queued_show, cfqd->cfq_queued, 0); 2276SHOW_FUNCTION(cfq_queued_show, cfqd->cfq_queued, 0);
1672SHOW_FUNCTION(cfq_fifo_expire_r_show, cfqd->cfq_fifo_expire_r, 1); 2277SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1);
1673SHOW_FUNCTION(cfq_fifo_expire_w_show, cfqd->cfq_fifo_expire_w, 1); 2278SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1);
1674SHOW_FUNCTION(cfq_fifo_batch_expire_show, cfqd->cfq_fifo_batch_expire, 1);
1675SHOW_FUNCTION(cfq_find_best_show, cfqd->find_best_crq, 0);
1676SHOW_FUNCTION(cfq_back_max_show, cfqd->cfq_back_max, 0); 2279SHOW_FUNCTION(cfq_back_max_show, cfqd->cfq_back_max, 0);
1677SHOW_FUNCTION(cfq_back_penalty_show, cfqd->cfq_back_penalty, 0); 2280SHOW_FUNCTION(cfq_back_penalty_show, cfqd->cfq_back_penalty, 0);
2281SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1);
2282SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1);
2283SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1);
2284SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0);
2285SHOW_FUNCTION(cfq_max_depth_show, cfqd->cfq_max_depth, 0);
1678#undef SHOW_FUNCTION 2286#undef SHOW_FUNCTION
1679 2287
1680#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ 2288#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \
@@ -1694,12 +2302,15 @@ static ssize_t __FUNC(struct cfq_data *cfqd, const char *page, size_t count) \
1694} 2302}
1695STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); 2303STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0);
1696STORE_FUNCTION(cfq_queued_store, &cfqd->cfq_queued, 1, UINT_MAX, 0); 2304STORE_FUNCTION(cfq_queued_store, &cfqd->cfq_queued, 1, UINT_MAX, 0);
1697STORE_FUNCTION(cfq_fifo_expire_r_store, &cfqd->cfq_fifo_expire_r, 1, UINT_MAX, 1); 2305STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, UINT_MAX, 1);
1698STORE_FUNCTION(cfq_fifo_expire_w_store, &cfqd->cfq_fifo_expire_w, 1, UINT_MAX, 1); 2306STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, UINT_MAX, 1);
1699STORE_FUNCTION(cfq_fifo_batch_expire_store, &cfqd->cfq_fifo_batch_expire, 0, UINT_MAX, 1);
1700STORE_FUNCTION(cfq_find_best_store, &cfqd->find_best_crq, 0, 1, 0);
1701STORE_FUNCTION(cfq_back_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); 2307STORE_FUNCTION(cfq_back_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0);
1702STORE_FUNCTION(cfq_back_penalty_store, &cfqd->cfq_back_penalty, 1, UINT_MAX, 0); 2308STORE_FUNCTION(cfq_back_penalty_store, &cfqd->cfq_back_penalty, 1, UINT_MAX, 0);
2309STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1);
2310STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1);
2311STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1);
2312STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, UINT_MAX, 0);
2313STORE_FUNCTION(cfq_max_depth_store, &cfqd->cfq_max_depth, 1, UINT_MAX, 0);
1703#undef STORE_FUNCTION 2314#undef STORE_FUNCTION
1704 2315
1705static struct cfq_fs_entry cfq_quantum_entry = { 2316static struct cfq_fs_entry cfq_quantum_entry = {
@@ -1712,25 +2323,15 @@ static struct cfq_fs_entry cfq_queued_entry = {
1712 .show = cfq_queued_show, 2323 .show = cfq_queued_show,
1713 .store = cfq_queued_store, 2324 .store = cfq_queued_store,
1714}; 2325};
1715static struct cfq_fs_entry cfq_fifo_expire_r_entry = { 2326static struct cfq_fs_entry cfq_fifo_expire_sync_entry = {
1716 .attr = {.name = "fifo_expire_sync", .mode = S_IRUGO | S_IWUSR }, 2327 .attr = {.name = "fifo_expire_sync", .mode = S_IRUGO | S_IWUSR },
1717 .show = cfq_fifo_expire_r_show, 2328 .show = cfq_fifo_expire_sync_show,
1718 .store = cfq_fifo_expire_r_store, 2329 .store = cfq_fifo_expire_sync_store,
1719}; 2330};
1720static struct cfq_fs_entry cfq_fifo_expire_w_entry = { 2331static struct cfq_fs_entry cfq_fifo_expire_async_entry = {
1721 .attr = {.name = "fifo_expire_async", .mode = S_IRUGO | S_IWUSR }, 2332 .attr = {.name = "fifo_expire_async", .mode = S_IRUGO | S_IWUSR },
1722 .show = cfq_fifo_expire_w_show, 2333 .show = cfq_fifo_expire_async_show,
1723 .store = cfq_fifo_expire_w_store, 2334 .store = cfq_fifo_expire_async_store,
1724};
1725static struct cfq_fs_entry cfq_fifo_batch_expire_entry = {
1726 .attr = {.name = "fifo_batch_expire", .mode = S_IRUGO | S_IWUSR },
1727 .show = cfq_fifo_batch_expire_show,
1728 .store = cfq_fifo_batch_expire_store,
1729};
1730static struct cfq_fs_entry cfq_find_best_entry = {
1731 .attr = {.name = "find_best_crq", .mode = S_IRUGO | S_IWUSR },
1732 .show = cfq_find_best_show,
1733 .store = cfq_find_best_store,
1734}; 2335};
1735static struct cfq_fs_entry cfq_back_max_entry = { 2336static struct cfq_fs_entry cfq_back_max_entry = {
1736 .attr = {.name = "back_seek_max", .mode = S_IRUGO | S_IWUSR }, 2337 .attr = {.name = "back_seek_max", .mode = S_IRUGO | S_IWUSR },
@@ -1742,27 +2343,43 @@ static struct cfq_fs_entry cfq_back_penalty_entry = {
1742 .show = cfq_back_penalty_show, 2343 .show = cfq_back_penalty_show,
1743 .store = cfq_back_penalty_store, 2344 .store = cfq_back_penalty_store,
1744}; 2345};
1745static struct cfq_fs_entry cfq_clear_elapsed_entry = { 2346static struct cfq_fs_entry cfq_slice_sync_entry = {
1746 .attr = {.name = "clear_elapsed", .mode = S_IWUSR }, 2347 .attr = {.name = "slice_sync", .mode = S_IRUGO | S_IWUSR },
1747 .store = cfq_clear_elapsed, 2348 .show = cfq_slice_sync_show,
2349 .store = cfq_slice_sync_store,
1748}; 2350};
1749static struct cfq_fs_entry cfq_key_type_entry = { 2351static struct cfq_fs_entry cfq_slice_async_entry = {
1750 .attr = {.name = "key_type", .mode = S_IRUGO | S_IWUSR }, 2352 .attr = {.name = "slice_async", .mode = S_IRUGO | S_IWUSR },
1751 .show = cfq_read_key_type, 2353 .show = cfq_slice_async_show,
1752 .store = cfq_set_key_type, 2354 .store = cfq_slice_async_store,
2355};
2356static struct cfq_fs_entry cfq_slice_async_rq_entry = {
2357 .attr = {.name = "slice_async_rq", .mode = S_IRUGO | S_IWUSR },
2358 .show = cfq_slice_async_rq_show,
2359 .store = cfq_slice_async_rq_store,
2360};
2361static struct cfq_fs_entry cfq_slice_idle_entry = {
2362 .attr = {.name = "slice_idle", .mode = S_IRUGO | S_IWUSR },
2363 .show = cfq_slice_idle_show,
2364 .store = cfq_slice_idle_store,
2365};
2366static struct cfq_fs_entry cfq_max_depth_entry = {
2367 .attr = {.name = "max_depth", .mode = S_IRUGO | S_IWUSR },
2368 .show = cfq_max_depth_show,
2369 .store = cfq_max_depth_store,
1753}; 2370};
1754
1755static struct attribute *default_attrs[] = { 2371static struct attribute *default_attrs[] = {
1756 &cfq_quantum_entry.attr, 2372 &cfq_quantum_entry.attr,
1757 &cfq_queued_entry.attr, 2373 &cfq_queued_entry.attr,
1758 &cfq_fifo_expire_r_entry.attr, 2374 &cfq_fifo_expire_sync_entry.attr,
1759 &cfq_fifo_expire_w_entry.attr, 2375 &cfq_fifo_expire_async_entry.attr,
1760 &cfq_fifo_batch_expire_entry.attr,
1761 &cfq_key_type_entry.attr,
1762 &cfq_find_best_entry.attr,
1763 &cfq_back_max_entry.attr, 2376 &cfq_back_max_entry.attr,
1764 &cfq_back_penalty_entry.attr, 2377 &cfq_back_penalty_entry.attr,
1765 &cfq_clear_elapsed_entry.attr, 2378 &cfq_slice_sync_entry.attr,
2379 &cfq_slice_async_entry.attr,
2380 &cfq_slice_async_rq_entry.attr,
2381 &cfq_slice_idle_entry.attr,
2382 &cfq_max_depth_entry.attr,
1766 NULL, 2383 NULL,
1767}; 2384};
1768 2385
@@ -1832,21 +2449,46 @@ static int __init cfq_init(void)
1832{ 2449{
1833 int ret; 2450 int ret;
1834 2451
2452 /*
2453 * could be 0 on HZ < 1000 setups
2454 */
2455 if (!cfq_slice_async)
2456 cfq_slice_async = 1;
2457 if (!cfq_slice_idle)
2458 cfq_slice_idle = 1;
2459
1835 if (cfq_slab_setup()) 2460 if (cfq_slab_setup())
1836 return -ENOMEM; 2461 return -ENOMEM;
1837 2462
1838 ret = elv_register(&iosched_cfq); 2463 ret = elv_register(&iosched_cfq);
1839 if (!ret) { 2464 if (ret)
1840 __module_get(THIS_MODULE); 2465 cfq_slab_kill();
1841 return 0;
1842 }
1843 2466
1844 cfq_slab_kill();
1845 return ret; 2467 return ret;
1846} 2468}
1847 2469
1848static void __exit cfq_exit(void) 2470static void __exit cfq_exit(void)
1849{ 2471{
2472 struct task_struct *g, *p;
2473 unsigned long flags;
2474
2475 read_lock_irqsave(&tasklist_lock, flags);
2476
2477 /*
2478 * iterate each process in the system, removing our io_context
2479 */
2480 do_each_thread(g, p) {
2481 struct io_context *ioc = p->io_context;
2482
2483 if (ioc && ioc->cic) {
2484 ioc->cic->exit(ioc->cic);
2485 cfq_free_io_context(ioc->cic);
2486 ioc->cic = NULL;
2487 }
2488 } while_each_thread(g, p);
2489
2490 read_unlock_irqrestore(&tasklist_lock, flags);
2491
1850 cfq_slab_kill(); 2492 cfq_slab_kill();
1851 elv_unregister(&iosched_cfq); 2493 elv_unregister(&iosched_cfq);
1852} 2494}
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-10 04:57:04 -0500