Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | * |
Jens Axboe | 0fe2347 | 2006-09-04 15:41:16 +0200 | [diff] [blame] | 7 | * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 8 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 9 | #include <linux/module.h> |
Al Viro | 1cc9be6 | 2006-03-18 12:29:52 -0500 | [diff] [blame] | 10 | #include <linux/blkdev.h> |
| 11 | #include <linux/elevator.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 12 | #include <linux/hash.h> |
| 13 | #include <linux/rbtree.h> |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 14 | #include <linux/ioprio.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 15 | |
| 16 | /* |
| 17 | * tunables |
| 18 | */ |
Arjan van de Ven | 6410009 | 2006-01-06 09:46:02 +0100 | [diff] [blame] | 19 | static const int cfq_quantum = 4; /* max queue in one round of service */ |
Arjan van de Ven | 6410009 | 2006-01-06 09:46:02 +0100 | [diff] [blame] | 20 | static const int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 }; |
| 21 | static const int cfq_back_max = 16 * 1024; /* maximum backwards seek, in KiB */ |
| 22 | static const int cfq_back_penalty = 2; /* penalty of a backwards seek */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 23 | |
Arjan van de Ven | 6410009 | 2006-01-06 09:46:02 +0100 | [diff] [blame] | 24 | static const int cfq_slice_sync = HZ / 10; |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 25 | static int cfq_slice_async = HZ / 25; |
Arjan van de Ven | 6410009 | 2006-01-06 09:46:02 +0100 | [diff] [blame] | 26 | static const int cfq_slice_async_rq = 2; |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 27 | static int cfq_slice_idle = HZ / 125; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 28 | |
| 29 | #define CFQ_IDLE_GRACE (HZ / 10) |
| 30 | #define CFQ_SLICE_SCALE (5) |
| 31 | |
| 32 | #define CFQ_KEY_ASYNC (0) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 33 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 34 | /* |
| 35 | * for the hash of cfqq inside the cfqd |
| 36 | */ |
| 37 | #define CFQ_QHASH_SHIFT 6 |
| 38 | #define CFQ_QHASH_ENTRIES (1 << CFQ_QHASH_SHIFT) |
| 39 | #define list_entry_qhash(entry) hlist_entry((entry), struct cfq_queue, cfq_hash) |
| 40 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 41 | #define list_entry_cfqq(ptr) list_entry((ptr), struct cfq_queue, cfq_list) |
| 42 | |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 43 | #define RQ_CIC(rq) ((struct cfq_io_context*)(rq)->elevator_private) |
| 44 | #define RQ_CFQQ(rq) ((rq)->elevator_private2) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 45 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 46 | static kmem_cache_t *cfq_pool; |
| 47 | static kmem_cache_t *cfq_ioc_pool; |
| 48 | |
Jens Axboe | 4050cf1 | 2006-07-19 05:07:12 +0200 | [diff] [blame] | 49 | static DEFINE_PER_CPU(unsigned long, ioc_count); |
Al Viro | 334e94d | 2006-03-18 15:05:53 -0500 | [diff] [blame] | 50 | static struct completion *ioc_gone; |
| 51 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 52 | #define CFQ_PRIO_LISTS IOPRIO_BE_NR |
| 53 | #define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 54 | #define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT) |
| 55 | |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 56 | #define ASYNC (0) |
| 57 | #define SYNC (1) |
| 58 | |
| 59 | #define cfq_cfqq_dispatched(cfqq) \ |
| 60 | ((cfqq)->on_dispatch[ASYNC] + (cfqq)->on_dispatch[SYNC]) |
| 61 | |
| 62 | #define cfq_cfqq_class_sync(cfqq) ((cfqq)->key != CFQ_KEY_ASYNC) |
| 63 | |
| 64 | #define cfq_cfqq_sync(cfqq) \ |
| 65 | (cfq_cfqq_class_sync(cfqq) || (cfqq)->on_dispatch[SYNC]) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 66 | |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 67 | #define sample_valid(samples) ((samples) > 80) |
| 68 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 69 | /* |
| 70 | * Per block device queue structure |
| 71 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 72 | struct cfq_data { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 73 | request_queue_t *queue; |
| 74 | |
| 75 | /* |
| 76 | * rr list of queues with requests and the count of them |
| 77 | */ |
| 78 | struct list_head rr_list[CFQ_PRIO_LISTS]; |
| 79 | struct list_head busy_rr; |
| 80 | struct list_head cur_rr; |
| 81 | struct list_head idle_rr; |
| 82 | unsigned int busy_queues; |
| 83 | |
| 84 | /* |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 85 | * cfqq lookup hash |
| 86 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 87 | struct hlist_head *cfq_hash; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 88 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 89 | int rq_in_driver; |
Jens Axboe | 25776e3 | 2006-06-01 10:12:26 +0200 | [diff] [blame] | 90 | int hw_tag; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 91 | |
| 92 | /* |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 93 | * idle window management |
| 94 | */ |
| 95 | struct timer_list idle_slice_timer; |
| 96 | struct work_struct unplug_work; |
| 97 | |
| 98 | struct cfq_queue *active_queue; |
| 99 | struct cfq_io_context *active_cic; |
| 100 | int cur_prio, cur_end_prio; |
| 101 | unsigned int dispatch_slice; |
| 102 | |
| 103 | struct timer_list idle_class_timer; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 104 | |
| 105 | sector_t last_sector; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 106 | unsigned long last_end_request; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 107 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 108 | /* |
| 109 | * tunables, see top of file |
| 110 | */ |
| 111 | unsigned int cfq_quantum; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 112 | unsigned int cfq_fifo_expire[2]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 113 | unsigned int cfq_back_penalty; |
| 114 | unsigned int cfq_back_max; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 115 | unsigned int cfq_slice[2]; |
| 116 | unsigned int cfq_slice_async_rq; |
| 117 | unsigned int cfq_slice_idle; |
Al Viro | d9ff418 | 2006-03-18 13:51:22 -0500 | [diff] [blame] | 118 | |
| 119 | struct list_head cic_list; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 120 | }; |
| 121 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 122 | /* |
| 123 | * Per process-grouping structure |
| 124 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 125 | struct cfq_queue { |
| 126 | /* reference count */ |
| 127 | atomic_t ref; |
| 128 | /* parent cfq_data */ |
| 129 | struct cfq_data *cfqd; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 130 | /* cfqq lookup hash */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 131 | struct hlist_node cfq_hash; |
| 132 | /* hash key */ |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 133 | unsigned int key; |
Jens Axboe | 981a797 | 2006-07-19 14:56:28 +0200 | [diff] [blame] | 134 | /* member of the rr/busy/cur/idle cfqd list */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 135 | struct list_head cfq_list; |
| 136 | /* sorted list of pending requests */ |
| 137 | struct rb_root sort_list; |
| 138 | /* if fifo isn't expired, next request to serve */ |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 139 | struct request *next_rq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 140 | /* requests queued in sort_list */ |
| 141 | int queued[2]; |
| 142 | /* currently allocated requests */ |
| 143 | int allocated[2]; |
Jens Axboe | 374f84a | 2006-07-23 01:42:19 +0200 | [diff] [blame] | 144 | /* pending metadata requests */ |
| 145 | int meta_pending; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 146 | /* fifo list of requests in sort_list */ |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 147 | struct list_head fifo; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 148 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 149 | unsigned long slice_start; |
| 150 | unsigned long slice_end; |
| 151 | unsigned long slice_left; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 152 | |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 153 | /* number of requests that are on the dispatch list */ |
| 154 | int on_dispatch[2]; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 155 | |
| 156 | /* io prio of this group */ |
| 157 | unsigned short ioprio, org_ioprio; |
| 158 | unsigned short ioprio_class, org_ioprio_class; |
| 159 | |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 160 | /* various state flags, see below */ |
| 161 | unsigned int flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 162 | }; |
| 163 | |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 164 | enum cfqq_state_flags { |
| 165 | CFQ_CFQQ_FLAG_on_rr = 0, |
| 166 | CFQ_CFQQ_FLAG_wait_request, |
| 167 | CFQ_CFQQ_FLAG_must_alloc, |
| 168 | CFQ_CFQQ_FLAG_must_alloc_slice, |
| 169 | CFQ_CFQQ_FLAG_must_dispatch, |
| 170 | CFQ_CFQQ_FLAG_fifo_expire, |
| 171 | CFQ_CFQQ_FLAG_idle_window, |
| 172 | CFQ_CFQQ_FLAG_prio_changed, |
Jens Axboe | 53b03744 | 2006-07-28 09:48:51 +0200 | [diff] [blame] | 173 | CFQ_CFQQ_FLAG_queue_new, |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 174 | }; |
| 175 | |
| 176 | #define CFQ_CFQQ_FNS(name) \ |
| 177 | static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \ |
| 178 | { \ |
| 179 | cfqq->flags |= (1 << CFQ_CFQQ_FLAG_##name); \ |
| 180 | } \ |
| 181 | static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \ |
| 182 | { \ |
| 183 | cfqq->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \ |
| 184 | } \ |
| 185 | static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \ |
| 186 | { \ |
| 187 | return (cfqq->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \ |
| 188 | } |
| 189 | |
| 190 | CFQ_CFQQ_FNS(on_rr); |
| 191 | CFQ_CFQQ_FNS(wait_request); |
| 192 | CFQ_CFQQ_FNS(must_alloc); |
| 193 | CFQ_CFQQ_FNS(must_alloc_slice); |
| 194 | CFQ_CFQQ_FNS(must_dispatch); |
| 195 | CFQ_CFQQ_FNS(fifo_expire); |
| 196 | CFQ_CFQQ_FNS(idle_window); |
| 197 | CFQ_CFQQ_FNS(prio_changed); |
Jens Axboe | 53b03744 | 2006-07-28 09:48:51 +0200 | [diff] [blame] | 198 | CFQ_CFQQ_FNS(queue_new); |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 199 | #undef CFQ_CFQQ_FNS |
| 200 | |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 201 | static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsigned short); |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 202 | static void cfq_dispatch_insert(request_queue_t *, struct request *); |
Al Viro | 6f325a1 | 2006-03-18 14:58:37 -0500 | [diff] [blame] | 203 | static struct cfq_queue *cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk, gfp_t gfp_mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 204 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 205 | /* |
Andrew Morton | 99f95e5 | 2005-06-27 20:14:05 -0700 | [diff] [blame] | 206 | * scheduler run of queue, if there are requests pending and no one in the |
| 207 | * driver that will restart queueing |
| 208 | */ |
| 209 | static inline void cfq_schedule_dispatch(struct cfq_data *cfqd) |
| 210 | { |
Jens Axboe | 7b14e3b | 2006-02-28 09:35:11 +0100 | [diff] [blame] | 211 | if (cfqd->busy_queues) |
Andrew Morton | 99f95e5 | 2005-06-27 20:14:05 -0700 | [diff] [blame] | 212 | kblockd_schedule_work(&cfqd->unplug_work); |
| 213 | } |
| 214 | |
| 215 | static int cfq_queue_empty(request_queue_t *q) |
| 216 | { |
| 217 | struct cfq_data *cfqd = q->elevator->elevator_data; |
| 218 | |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 219 | return !cfqd->busy_queues; |
Andrew Morton | 99f95e5 | 2005-06-27 20:14:05 -0700 | [diff] [blame] | 220 | } |
| 221 | |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 222 | static inline pid_t cfq_queue_pid(struct task_struct *task, int rw) |
| 223 | { |
Jens Axboe | b31dc66 | 2006-06-13 08:26:10 +0200 | [diff] [blame] | 224 | if (rw == READ || rw == WRITE_SYNC) |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 225 | return task->pid; |
| 226 | |
| 227 | return CFQ_KEY_ASYNC; |
| 228 | } |
| 229 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 230 | /* |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 231 | * Lifted from AS - choose which of rq1 and rq2 that is best served now. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 232 | * We choose the request that is closest to the head right now. Distance |
Andreas Mohr | e8a9905 | 2006-03-28 08:59:49 +0200 | [diff] [blame] | 233 | * behind the head is penalized and only allowed to a certain extent. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 234 | */ |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 235 | static struct request * |
| 236 | cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 237 | { |
| 238 | sector_t last, s1, s2, d1 = 0, d2 = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 239 | unsigned long back_max; |
Andreas Mohr | e8a9905 | 2006-03-28 08:59:49 +0200 | [diff] [blame] | 240 | #define CFQ_RQ1_WRAP 0x01 /* request 1 wraps */ |
| 241 | #define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */ |
| 242 | unsigned wrap = 0; /* bit mask: requests behind the disk head? */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 243 | |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 244 | if (rq1 == NULL || rq1 == rq2) |
| 245 | return rq2; |
| 246 | if (rq2 == NULL) |
| 247 | return rq1; |
Jens Axboe | 9c2c38a | 2005-08-24 14:57:54 +0200 | [diff] [blame] | 248 | |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 249 | if (rq_is_sync(rq1) && !rq_is_sync(rq2)) |
| 250 | return rq1; |
| 251 | else if (rq_is_sync(rq2) && !rq_is_sync(rq1)) |
| 252 | return rq2; |
Jens Axboe | 374f84a | 2006-07-23 01:42:19 +0200 | [diff] [blame] | 253 | if (rq_is_meta(rq1) && !rq_is_meta(rq2)) |
| 254 | return rq1; |
| 255 | else if (rq_is_meta(rq2) && !rq_is_meta(rq1)) |
| 256 | return rq2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 257 | |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 258 | s1 = rq1->sector; |
| 259 | s2 = rq2->sector; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 260 | |
| 261 | last = cfqd->last_sector; |
| 262 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 263 | /* |
| 264 | * by definition, 1KiB is 2 sectors |
| 265 | */ |
| 266 | back_max = cfqd->cfq_back_max * 2; |
| 267 | |
| 268 | /* |
| 269 | * Strict one way elevator _except_ in the case where we allow |
| 270 | * short backward seeks which are biased as twice the cost of a |
| 271 | * similar forward seek. |
| 272 | */ |
| 273 | if (s1 >= last) |
| 274 | d1 = s1 - last; |
| 275 | else if (s1 + back_max >= last) |
| 276 | d1 = (last - s1) * cfqd->cfq_back_penalty; |
| 277 | else |
Andreas Mohr | e8a9905 | 2006-03-28 08:59:49 +0200 | [diff] [blame] | 278 | wrap |= CFQ_RQ1_WRAP; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 279 | |
| 280 | if (s2 >= last) |
| 281 | d2 = s2 - last; |
| 282 | else if (s2 + back_max >= last) |
| 283 | d2 = (last - s2) * cfqd->cfq_back_penalty; |
| 284 | else |
Andreas Mohr | e8a9905 | 2006-03-28 08:59:49 +0200 | [diff] [blame] | 285 | wrap |= CFQ_RQ2_WRAP; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 286 | |
| 287 | /* Found required data */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 288 | |
Andreas Mohr | e8a9905 | 2006-03-28 08:59:49 +0200 | [diff] [blame] | 289 | /* |
| 290 | * By doing switch() on the bit mask "wrap" we avoid having to |
| 291 | * check two variables for all permutations: --> faster! |
| 292 | */ |
| 293 | switch (wrap) { |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 294 | case 0: /* common case for CFQ: rq1 and rq2 not wrapped */ |
Andreas Mohr | e8a9905 | 2006-03-28 08:59:49 +0200 | [diff] [blame] | 295 | if (d1 < d2) |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 296 | return rq1; |
Andreas Mohr | e8a9905 | 2006-03-28 08:59:49 +0200 | [diff] [blame] | 297 | else if (d2 < d1) |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 298 | return rq2; |
Andreas Mohr | e8a9905 | 2006-03-28 08:59:49 +0200 | [diff] [blame] | 299 | else { |
| 300 | if (s1 >= s2) |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 301 | return rq1; |
Andreas Mohr | e8a9905 | 2006-03-28 08:59:49 +0200 | [diff] [blame] | 302 | else |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 303 | return rq2; |
Andreas Mohr | e8a9905 | 2006-03-28 08:59:49 +0200 | [diff] [blame] | 304 | } |
| 305 | |
| 306 | case CFQ_RQ2_WRAP: |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 307 | return rq1; |
Andreas Mohr | e8a9905 | 2006-03-28 08:59:49 +0200 | [diff] [blame] | 308 | case CFQ_RQ1_WRAP: |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 309 | return rq2; |
| 310 | case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both rqs wrapped */ |
Andreas Mohr | e8a9905 | 2006-03-28 08:59:49 +0200 | [diff] [blame] | 311 | default: |
| 312 | /* |
| 313 | * Since both rqs are wrapped, |
| 314 | * start with the one that's further behind head |
| 315 | * (--> only *one* back seek required), |
| 316 | * since back seek takes more time than forward. |
| 317 | */ |
| 318 | if (s1 <= s2) |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 319 | return rq1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 320 | else |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 321 | return rq2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 322 | } |
| 323 | } |
| 324 | |
| 325 | /* |
| 326 | * would be nice to take fifo expire time into account as well |
| 327 | */ |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 328 | static struct request * |
| 329 | cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
| 330 | struct request *last) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 331 | { |
Jens Axboe | 21183b0 | 2006-07-13 12:33:14 +0200 | [diff] [blame] | 332 | struct rb_node *rbnext = rb_next(&last->rb_node); |
| 333 | struct rb_node *rbprev = rb_prev(&last->rb_node); |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 334 | struct request *next = NULL, *prev = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 335 | |
Jens Axboe | 21183b0 | 2006-07-13 12:33:14 +0200 | [diff] [blame] | 336 | BUG_ON(RB_EMPTY_NODE(&last->rb_node)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 337 | |
| 338 | if (rbprev) |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 339 | prev = rb_entry_rq(rbprev); |
Jens Axboe | 21183b0 | 2006-07-13 12:33:14 +0200 | [diff] [blame] | 340 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 341 | if (rbnext) |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 342 | next = rb_entry_rq(rbnext); |
Jens Axboe | 21183b0 | 2006-07-13 12:33:14 +0200 | [diff] [blame] | 343 | else { |
| 344 | rbnext = rb_first(&cfqq->sort_list); |
| 345 | if (rbnext && rbnext != &last->rb_node) |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 346 | next = rb_entry_rq(rbnext); |
Jens Axboe | 21183b0 | 2006-07-13 12:33:14 +0200 | [diff] [blame] | 347 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 348 | |
Jens Axboe | 21183b0 | 2006-07-13 12:33:14 +0200 | [diff] [blame] | 349 | return cfq_choose_req(cfqd, next, prev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 350 | } |
| 351 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 352 | static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 353 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 354 | struct cfq_data *cfqd = cfqq->cfqd; |
Jens Axboe | 53b03744 | 2006-07-28 09:48:51 +0200 | [diff] [blame] | 355 | struct list_head *list; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 356 | |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 357 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 358 | |
| 359 | list_del(&cfqq->cfq_list); |
| 360 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 361 | if (cfq_class_rt(cfqq)) |
| 362 | list = &cfqd->cur_rr; |
| 363 | else if (cfq_class_idle(cfqq)) |
| 364 | list = &cfqd->idle_rr; |
| 365 | else { |
| 366 | /* |
| 367 | * if cfqq has requests in flight, don't allow it to be |
| 368 | * found in cfq_set_active_queue before it has finished them. |
| 369 | * this is done to increase fairness between a process that |
| 370 | * has lots of io pending vs one that only generates one |
| 371 | * sporadically or synchronously |
| 372 | */ |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 373 | if (cfq_cfqq_dispatched(cfqq)) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 374 | list = &cfqd->busy_rr; |
| 375 | else |
| 376 | list = &cfqd->rr_list[cfqq->ioprio]; |
| 377 | } |
| 378 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 379 | /* |
Jens Axboe | 53b03744 | 2006-07-28 09:48:51 +0200 | [diff] [blame] | 380 | * If this queue was preempted or is new (never been serviced), let |
| 381 | * it be added first for fairness but beind other new queues. |
| 382 | * Otherwise, just add to the back of the list. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 383 | */ |
Jens Axboe | 53b03744 | 2006-07-28 09:48:51 +0200 | [diff] [blame] | 384 | if (preempted || cfq_cfqq_queue_new(cfqq)) { |
| 385 | struct list_head *n = list; |
| 386 | struct cfq_queue *__cfqq; |
Jens Axboe | b52a834 | 2006-06-01 18:53:43 +0200 | [diff] [blame] | 387 | |
Jens Axboe | 53b03744 | 2006-07-28 09:48:51 +0200 | [diff] [blame] | 388 | while (n->next != list) { |
| 389 | __cfqq = list_entry_cfqq(n->next); |
| 390 | if (!cfq_cfqq_queue_new(__cfqq)) |
| 391 | break; |
| 392 | |
| 393 | n = n->next; |
| 394 | } |
| 395 | |
| 396 | list = n; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 397 | } |
| 398 | |
Jens Axboe | 53b03744 | 2006-07-28 09:48:51 +0200 | [diff] [blame] | 399 | list_add_tail(&cfqq->cfq_list, list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 400 | } |
| 401 | |
| 402 | /* |
| 403 | * add to busy list of queues for service, trying to be fair in ordering |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 404 | * the pending list according to last request service |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 405 | */ |
| 406 | static inline void |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 407 | cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 408 | { |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 409 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
| 410 | cfq_mark_cfqq_on_rr(cfqq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 411 | cfqd->busy_queues++; |
| 412 | |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 413 | cfq_resort_rr_list(cfqq, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 414 | } |
| 415 | |
| 416 | static inline void |
| 417 | cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
| 418 | { |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 419 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
| 420 | cfq_clear_cfqq_on_rr(cfqq); |
Jens Axboe | 981a797 | 2006-07-19 14:56:28 +0200 | [diff] [blame] | 421 | list_del_init(&cfqq->cfq_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 422 | |
| 423 | BUG_ON(!cfqd->busy_queues); |
| 424 | cfqd->busy_queues--; |
| 425 | } |
| 426 | |
| 427 | /* |
| 428 | * rb tree support functions |
| 429 | */ |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 430 | static inline void cfq_del_rq_rb(struct request *rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 431 | { |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 432 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 433 | struct cfq_data *cfqd = cfqq->cfqd; |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 434 | const int sync = rq_is_sync(rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 435 | |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 436 | BUG_ON(!cfqq->queued[sync]); |
| 437 | cfqq->queued[sync]--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 438 | |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 439 | elv_rb_del(&cfqq->sort_list, rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 440 | |
Jens Axboe | dd67d05 | 2006-06-21 09:36:18 +0200 | [diff] [blame] | 441 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 442 | cfq_del_cfqq_rr(cfqd, cfqq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 443 | } |
| 444 | |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 445 | static void cfq_add_rq_rb(struct request *rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 446 | { |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 447 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 448 | struct cfq_data *cfqd = cfqq->cfqd; |
Jens Axboe | 21183b0 | 2006-07-13 12:33:14 +0200 | [diff] [blame] | 449 | struct request *__alias; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 450 | |
Jens Axboe | 5380a10 | 2006-07-13 12:37:56 +0200 | [diff] [blame] | 451 | cfqq->queued[rq_is_sync(rq)]++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 452 | |
| 453 | /* |
| 454 | * looks a little odd, but the first insert might return an alias. |
| 455 | * if that happens, put the alias on the dispatch list |
| 456 | */ |
Jens Axboe | 21183b0 | 2006-07-13 12:33:14 +0200 | [diff] [blame] | 457 | while ((__alias = elv_rb_add(&cfqq->sort_list, rq)) != NULL) |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 458 | cfq_dispatch_insert(cfqd->queue, __alias); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 459 | } |
| 460 | |
| 461 | static inline void |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 462 | cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 463 | { |
Jens Axboe | 5380a10 | 2006-07-13 12:37:56 +0200 | [diff] [blame] | 464 | elv_rb_del(&cfqq->sort_list, rq); |
| 465 | cfqq->queued[rq_is_sync(rq)]--; |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 466 | cfq_add_rq_rb(rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 467 | } |
| 468 | |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 469 | static struct request * |
| 470 | cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 471 | { |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 472 | struct task_struct *tsk = current; |
| 473 | pid_t key = cfq_queue_pid(tsk, bio_data_dir(bio)); |
| 474 | struct cfq_queue *cfqq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 475 | |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 476 | cfqq = cfq_find_cfq_hash(cfqd, key, tsk->ioprio); |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 477 | if (cfqq) { |
| 478 | sector_t sector = bio->bi_sector + bio_sectors(bio); |
| 479 | |
Jens Axboe | 21183b0 | 2006-07-13 12:33:14 +0200 | [diff] [blame] | 480 | return elv_rb_find(&cfqq->sort_list, sector); |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 481 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 482 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 483 | return NULL; |
| 484 | } |
| 485 | |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 486 | static void cfq_activate_request(request_queue_t *q, struct request *rq) |
| 487 | { |
| 488 | struct cfq_data *cfqd = q->elevator->elevator_data; |
| 489 | |
| 490 | cfqd->rq_in_driver++; |
Jens Axboe | 25776e3 | 2006-06-01 10:12:26 +0200 | [diff] [blame] | 491 | |
| 492 | /* |
| 493 | * If the depth is larger 1, it really could be queueing. But lets |
| 494 | * make the mark a little higher - idling could still be good for |
| 495 | * low queueing, and a low queueing number could also just indicate |
| 496 | * a SCSI mid layer like behaviour where limit+1 is often seen. |
| 497 | */ |
| 498 | if (!cfqd->hw_tag && cfqd->rq_in_driver > 4) |
| 499 | cfqd->hw_tag = 1; |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 500 | } |
| 501 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 502 | static void cfq_deactivate_request(request_queue_t *q, struct request *rq) |
| 503 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 504 | struct cfq_data *cfqd = q->elevator->elevator_data; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 505 | |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 506 | WARN_ON(!cfqd->rq_in_driver); |
| 507 | cfqd->rq_in_driver--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 508 | } |
| 509 | |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 510 | static void cfq_remove_request(struct request *rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 511 | { |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 512 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
Jens Axboe | 21183b0 | 2006-07-13 12:33:14 +0200 | [diff] [blame] | 513 | |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 514 | if (cfqq->next_rq == rq) |
| 515 | cfqq->next_rq = cfq_find_next_rq(cfqq->cfqd, cfqq, rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 516 | |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 517 | list_del_init(&rq->queuelist); |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 518 | cfq_del_rq_rb(rq); |
Jens Axboe | 374f84a | 2006-07-23 01:42:19 +0200 | [diff] [blame] | 519 | |
| 520 | if (rq_is_meta(rq)) { |
| 521 | WARN_ON(!cfqq->meta_pending); |
| 522 | cfqq->meta_pending--; |
| 523 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 524 | } |
| 525 | |
| 526 | static int |
| 527 | cfq_merge(request_queue_t *q, struct request **req, struct bio *bio) |
| 528 | { |
| 529 | struct cfq_data *cfqd = q->elevator->elevator_data; |
| 530 | struct request *__rq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 531 | |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 532 | __rq = cfq_find_rq_fmerge(cfqd, bio); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 533 | if (__rq && elv_rq_merge_ok(__rq, bio)) { |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 534 | *req = __rq; |
| 535 | return ELEVATOR_FRONT_MERGE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 536 | } |
| 537 | |
| 538 | return ELEVATOR_NO_MERGE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 539 | } |
| 540 | |
Jens Axboe | 21183b0 | 2006-07-13 12:33:14 +0200 | [diff] [blame] | 541 | static void cfq_merged_request(request_queue_t *q, struct request *req, |
| 542 | int type) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 543 | { |
Jens Axboe | 21183b0 | 2006-07-13 12:33:14 +0200 | [diff] [blame] | 544 | if (type == ELEVATOR_FRONT_MERGE) { |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 545 | struct cfq_queue *cfqq = RQ_CFQQ(req); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 546 | |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 547 | cfq_reposition_rq_rb(cfqq, req); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 548 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 549 | } |
| 550 | |
| 551 | static void |
| 552 | cfq_merged_requests(request_queue_t *q, struct request *rq, |
| 553 | struct request *next) |
| 554 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 555 | /* |
| 556 | * reposition in fifo if next is older than rq |
| 557 | */ |
| 558 | if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && |
| 559 | time_before(next->start_time, rq->start_time)) |
| 560 | list_move(&rq->queuelist, &next->queuelist); |
| 561 | |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 562 | cfq_remove_request(next); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 563 | } |
| 564 | |
| 565 | static inline void |
| 566 | __cfq_set_active_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
| 567 | { |
| 568 | if (cfqq) { |
| 569 | /* |
| 570 | * stop potential idle class queues waiting service |
| 571 | */ |
| 572 | del_timer(&cfqd->idle_class_timer); |
| 573 | |
| 574 | cfqq->slice_start = jiffies; |
| 575 | cfqq->slice_end = 0; |
| 576 | cfqq->slice_left = 0; |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 577 | cfq_clear_cfqq_must_alloc_slice(cfqq); |
| 578 | cfq_clear_cfqq_fifo_expire(cfqq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 579 | } |
| 580 | |
| 581 | cfqd->active_queue = cfqq; |
| 582 | } |
| 583 | |
| 584 | /* |
Jens Axboe | 7b14e3b | 2006-02-28 09:35:11 +0100 | [diff] [blame] | 585 | * current cfqq expired its slice (or was too idle), select new one |
| 586 | */ |
| 587 | static void |
| 588 | __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
| 589 | int preempted) |
| 590 | { |
| 591 | unsigned long now = jiffies; |
| 592 | |
| 593 | if (cfq_cfqq_wait_request(cfqq)) |
| 594 | del_timer(&cfqd->idle_slice_timer); |
| 595 | |
Jens Axboe | 53b03744 | 2006-07-28 09:48:51 +0200 | [diff] [blame] | 596 | if (!preempted && !cfq_cfqq_dispatched(cfqq)) |
Jens Axboe | 7b14e3b | 2006-02-28 09:35:11 +0100 | [diff] [blame] | 597 | cfq_schedule_dispatch(cfqd); |
Jens Axboe | 7b14e3b | 2006-02-28 09:35:11 +0100 | [diff] [blame] | 598 | |
| 599 | cfq_clear_cfqq_must_dispatch(cfqq); |
| 600 | cfq_clear_cfqq_wait_request(cfqq); |
Jens Axboe | 53b03744 | 2006-07-28 09:48:51 +0200 | [diff] [blame] | 601 | cfq_clear_cfqq_queue_new(cfqq); |
Jens Axboe | 7b14e3b | 2006-02-28 09:35:11 +0100 | [diff] [blame] | 602 | |
| 603 | /* |
| 604 | * store what was left of this slice, if the queue idled out |
| 605 | * or was preempted |
| 606 | */ |
| 607 | if (time_after(cfqq->slice_end, now)) |
| 608 | cfqq->slice_left = cfqq->slice_end - now; |
| 609 | else |
| 610 | cfqq->slice_left = 0; |
| 611 | |
| 612 | if (cfq_cfqq_on_rr(cfqq)) |
| 613 | cfq_resort_rr_list(cfqq, preempted); |
| 614 | |
| 615 | if (cfqq == cfqd->active_queue) |
| 616 | cfqd->active_queue = NULL; |
| 617 | |
| 618 | if (cfqd->active_cic) { |
| 619 | put_io_context(cfqd->active_cic->ioc); |
| 620 | cfqd->active_cic = NULL; |
| 621 | } |
| 622 | |
| 623 | cfqd->dispatch_slice = 0; |
| 624 | } |
| 625 | |
| 626 | static inline void cfq_slice_expired(struct cfq_data *cfqd, int preempted) |
| 627 | { |
| 628 | struct cfq_queue *cfqq = cfqd->active_queue; |
| 629 | |
| 630 | if (cfqq) |
| 631 | __cfq_slice_expired(cfqd, cfqq, preempted); |
| 632 | } |
| 633 | |
| 634 | /* |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 635 | * 0 |
| 636 | * 0,1 |
| 637 | * 0,1,2 |
| 638 | * 0,1,2,3 |
| 639 | * 0,1,2,3,4 |
| 640 | * 0,1,2,3,4,5 |
| 641 | * 0,1,2,3,4,5,6 |
| 642 | * 0,1,2,3,4,5,6,7 |
| 643 | */ |
| 644 | static int cfq_get_next_prio_level(struct cfq_data *cfqd) |
| 645 | { |
| 646 | int prio, wrap; |
| 647 | |
| 648 | prio = -1; |
| 649 | wrap = 0; |
| 650 | do { |
| 651 | int p; |
| 652 | |
| 653 | for (p = cfqd->cur_prio; p <= cfqd->cur_end_prio; p++) { |
| 654 | if (!list_empty(&cfqd->rr_list[p])) { |
| 655 | prio = p; |
| 656 | break; |
| 657 | } |
| 658 | } |
| 659 | |
| 660 | if (prio != -1) |
| 661 | break; |
| 662 | cfqd->cur_prio = 0; |
| 663 | if (++cfqd->cur_end_prio == CFQ_PRIO_LISTS) { |
| 664 | cfqd->cur_end_prio = 0; |
| 665 | if (wrap) |
| 666 | break; |
| 667 | wrap = 1; |
| 668 | } |
| 669 | } while (1); |
| 670 | |
| 671 | if (unlikely(prio == -1)) |
| 672 | return -1; |
| 673 | |
| 674 | BUG_ON(prio >= CFQ_PRIO_LISTS); |
| 675 | |
| 676 | list_splice_init(&cfqd->rr_list[prio], &cfqd->cur_rr); |
| 677 | |
| 678 | cfqd->cur_prio = prio + 1; |
| 679 | if (cfqd->cur_prio > cfqd->cur_end_prio) { |
| 680 | cfqd->cur_end_prio = cfqd->cur_prio; |
| 681 | cfqd->cur_prio = 0; |
| 682 | } |
| 683 | if (cfqd->cur_end_prio == CFQ_PRIO_LISTS) { |
| 684 | cfqd->cur_prio = 0; |
| 685 | cfqd->cur_end_prio = 0; |
| 686 | } |
| 687 | |
| 688 | return prio; |
| 689 | } |
| 690 | |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 691 | static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 692 | { |
Jens Axboe | 7b14e3b | 2006-02-28 09:35:11 +0100 | [diff] [blame] | 693 | struct cfq_queue *cfqq = NULL; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 694 | |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 695 | if (!list_empty(&cfqd->cur_rr) || cfq_get_next_prio_level(cfqd) != -1) { |
| 696 | /* |
| 697 | * if current list is non-empty, grab first entry. if it is |
| 698 | * empty, get next prio level and grab first entry then if any |
| 699 | * are spliced |
| 700 | */ |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 701 | cfqq = list_entry_cfqq(cfqd->cur_rr.next); |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 702 | } else if (!list_empty(&cfqd->busy_rr)) { |
| 703 | /* |
| 704 | * If no new queues are available, check if the busy list has |
| 705 | * some before falling back to idle io. |
| 706 | */ |
Jens Axboe | e0de020 | 2006-06-01 10:07:26 +0200 | [diff] [blame] | 707 | cfqq = list_entry_cfqq(cfqd->busy_rr.next); |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 708 | } else if (!list_empty(&cfqd->idle_rr)) { |
| 709 | /* |
| 710 | * if we have idle queues and no rt or be queues had pending |
| 711 | * requests, either allow immediate service if the grace period |
| 712 | * has passed or arm the idle grace timer |
| 713 | */ |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 714 | unsigned long end = cfqd->last_end_request + CFQ_IDLE_GRACE; |
| 715 | |
| 716 | if (time_after_eq(jiffies, end)) |
| 717 | cfqq = list_entry_cfqq(cfqd->idle_rr.next); |
| 718 | else |
| 719 | mod_timer(&cfqd->idle_class_timer, end); |
| 720 | } |
| 721 | |
| 722 | __cfq_set_active_queue(cfqd, cfqq); |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 723 | return cfqq; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 724 | } |
| 725 | |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 726 | #define CIC_SEEKY(cic) ((cic)->seek_mean > (128 * 1024)) |
| 727 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 728 | static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
| 729 | |
| 730 | { |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 731 | struct cfq_io_context *cic; |
Jens Axboe | 7b14e3b | 2006-02-28 09:35:11 +0100 | [diff] [blame] | 732 | unsigned long sl; |
| 733 | |
Jens Axboe | dd67d05 | 2006-06-21 09:36:18 +0200 | [diff] [blame] | 734 | WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list)); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 735 | WARN_ON(cfqq != cfqd->active_queue); |
| 736 | |
| 737 | /* |
| 738 | * idle is disabled, either manually or by past process history |
| 739 | */ |
| 740 | if (!cfqd->cfq_slice_idle) |
| 741 | return 0; |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 742 | if (!cfq_cfqq_idle_window(cfqq)) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 743 | return 0; |
| 744 | /* |
| 745 | * task has exited, don't wait |
| 746 | */ |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 747 | cic = cfqd->active_cic; |
| 748 | if (!cic || !cic->ioc->task) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 749 | return 0; |
| 750 | |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 751 | cfq_mark_cfqq_must_dispatch(cfqq); |
| 752 | cfq_mark_cfqq_wait_request(cfqq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 753 | |
Jens Axboe | 7b14e3b | 2006-02-28 09:35:11 +0100 | [diff] [blame] | 754 | sl = min(cfqq->slice_end - 1, (unsigned long) cfqd->cfq_slice_idle); |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 755 | |
| 756 | /* |
| 757 | * we don't want to idle for seeks, but we do want to allow |
| 758 | * fair distribution of slice time for a process doing back-to-back |
| 759 | * seeks. so allow a little bit of time for him to submit a new rq |
| 760 | */ |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 761 | if (sample_valid(cic->seek_samples) && CIC_SEEKY(cic)) |
Jens Axboe | 44eb123 | 2006-07-25 15:05:21 +0200 | [diff] [blame] | 762 | sl = min(sl, msecs_to_jiffies(2)); |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 763 | |
Jens Axboe | 7b14e3b | 2006-02-28 09:35:11 +0100 | [diff] [blame] | 764 | mod_timer(&cfqd->idle_slice_timer, jiffies + sl); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 765 | return 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 766 | } |
| 767 | |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 768 | static void cfq_dispatch_insert(request_queue_t *q, struct request *rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 769 | { |
| 770 | struct cfq_data *cfqd = q->elevator->elevator_data; |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 771 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 772 | |
Jens Axboe | 5380a10 | 2006-07-13 12:37:56 +0200 | [diff] [blame] | 773 | cfq_remove_request(rq); |
| 774 | cfqq->on_dispatch[rq_is_sync(rq)]++; |
| 775 | elv_dispatch_sort(q, rq); |
Jens Axboe | fd61af0 | 2006-06-16 15:35:39 +0200 | [diff] [blame] | 776 | |
| 777 | rq = list_entry(q->queue_head.prev, struct request, queuelist); |
| 778 | cfqd->last_sector = rq->sector + rq->nr_sectors; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 779 | } |
| 780 | |
| 781 | /* |
| 782 | * return expired entry, or NULL to just start from scratch in rbtree |
| 783 | */ |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 784 | static inline struct request *cfq_check_fifo(struct cfq_queue *cfqq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 785 | { |
| 786 | struct cfq_data *cfqd = cfqq->cfqd; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 787 | struct request *rq; |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 788 | int fifo; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 789 | |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 790 | if (cfq_cfqq_fifo_expire(cfqq)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 791 | return NULL; |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 792 | if (list_empty(&cfqq->fifo)) |
| 793 | return NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 794 | |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 795 | fifo = cfq_cfqq_class_sync(cfqq); |
| 796 | rq = rq_entry_fifo(cfqq->fifo.next); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 797 | |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 798 | if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) { |
| 799 | cfq_mark_cfqq_fifo_expire(cfqq); |
| 800 | return rq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 801 | } |
| 802 | |
| 803 | return NULL; |
| 804 | } |
| 805 | |
| 806 | /* |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 807 | * Scale schedule slice based on io priority. Use the sync time slice only |
| 808 | * if a queue is marked sync and has sync io queued. A sync queue with async |
| 809 | * io only, should not get full sync slice length. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 810 | */ |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 811 | static inline int |
| 812 | cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 813 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 814 | const int base_slice = cfqd->cfq_slice[cfq_cfqq_sync(cfqq)]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 815 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 816 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 817 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 818 | return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - cfqq->ioprio)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 819 | } |
| 820 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 821 | static inline void |
| 822 | cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
| 823 | { |
| 824 | cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies; |
| 825 | } |
| 826 | |
| 827 | static inline int |
| 828 | cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
| 829 | { |
| 830 | const int base_rq = cfqd->cfq_slice_async_rq; |
| 831 | |
| 832 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); |
| 833 | |
| 834 | return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio)); |
| 835 | } |
| 836 | |
| 837 | /* |
| 838 | * get next queue for service |
| 839 | */ |
Tejun Heo | 1b5ed5e1 | 2005-11-10 08:49:19 +0100 | [diff] [blame] | 840 | static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 841 | { |
| 842 | unsigned long now = jiffies; |
| 843 | struct cfq_queue *cfqq; |
| 844 | |
| 845 | cfqq = cfqd->active_queue; |
| 846 | if (!cfqq) |
| 847 | goto new_queue; |
| 848 | |
| 849 | /* |
| 850 | * slice has expired |
| 851 | */ |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 852 | if (!cfq_cfqq_must_dispatch(cfqq) && time_after(now, cfqq->slice_end)) |
| 853 | goto expire; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 854 | |
| 855 | /* |
| 856 | * if queue has requests, dispatch one. if not, check if |
| 857 | * enough slice is left to wait for one |
| 858 | */ |
Jens Axboe | dd67d05 | 2006-06-21 09:36:18 +0200 | [diff] [blame] | 859 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 860 | goto keep_queue; |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 861 | else if (cfq_cfqq_dispatched(cfqq)) { |
| 862 | cfqq = NULL; |
| 863 | goto keep_queue; |
| 864 | } else if (cfq_cfqq_class_sync(cfqq)) { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 865 | if (cfq_arm_slice_timer(cfqd, cfqq)) |
| 866 | return NULL; |
| 867 | } |
| 868 | |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 869 | expire: |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 870 | cfq_slice_expired(cfqd, 0); |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 871 | new_queue: |
| 872 | cfqq = cfq_set_active_queue(cfqd); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 873 | keep_queue: |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 874 | return cfqq; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 875 | } |
| 876 | |
| 877 | static int |
| 878 | __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
| 879 | int max_dispatch) |
| 880 | { |
| 881 | int dispatched = 0; |
| 882 | |
Jens Axboe | dd67d05 | 2006-06-21 09:36:18 +0200 | [diff] [blame] | 883 | BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list)); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 884 | |
| 885 | do { |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 886 | struct request *rq; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 887 | |
| 888 | /* |
| 889 | * follow expired path, else get first next available |
| 890 | */ |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 891 | if ((rq = cfq_check_fifo(cfqq)) == NULL) |
| 892 | rq = cfqq->next_rq; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 893 | |
| 894 | /* |
| 895 | * finally, insert request into driver dispatch list |
| 896 | */ |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 897 | cfq_dispatch_insert(cfqd->queue, rq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 898 | |
| 899 | cfqd->dispatch_slice++; |
| 900 | dispatched++; |
| 901 | |
| 902 | if (!cfqd->active_cic) { |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 903 | atomic_inc(&RQ_CIC(rq)->ioc->refcount); |
| 904 | cfqd->active_cic = RQ_CIC(rq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 905 | } |
| 906 | |
Jens Axboe | dd67d05 | 2006-06-21 09:36:18 +0200 | [diff] [blame] | 907 | if (RB_EMPTY_ROOT(&cfqq->sort_list)) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 908 | break; |
| 909 | |
| 910 | } while (dispatched < max_dispatch); |
| 911 | |
| 912 | /* |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 913 | * if slice end isn't set yet, set it. |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 914 | */ |
| 915 | if (!cfqq->slice_end) |
| 916 | cfq_set_prio_slice(cfqd, cfqq); |
| 917 | |
| 918 | /* |
| 919 | * expire an async queue immediately if it has used up its slice. idle |
| 920 | * queue always expire after 1 dispatch round. |
| 921 | */ |
| 922 | if ((!cfq_cfqq_sync(cfqq) && |
| 923 | cfqd->dispatch_slice >= cfq_prio_to_maxrq(cfqd, cfqq)) || |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 924 | cfq_class_idle(cfqq) || |
| 925 | !cfq_cfqq_idle_window(cfqq)) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 926 | cfq_slice_expired(cfqd, 0); |
| 927 | |
| 928 | return dispatched; |
| 929 | } |
| 930 | |
| 931 | static int |
Tejun Heo | 1b5ed5e1 | 2005-11-10 08:49:19 +0100 | [diff] [blame] | 932 | cfq_forced_dispatch_cfqqs(struct list_head *list) |
| 933 | { |
Tejun Heo | 1b5ed5e1 | 2005-11-10 08:49:19 +0100 | [diff] [blame] | 934 | struct cfq_queue *cfqq, *next; |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 935 | int dispatched; |
Tejun Heo | 1b5ed5e1 | 2005-11-10 08:49:19 +0100 | [diff] [blame] | 936 | |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 937 | dispatched = 0; |
Tejun Heo | 1b5ed5e1 | 2005-11-10 08:49:19 +0100 | [diff] [blame] | 938 | list_for_each_entry_safe(cfqq, next, list, cfq_list) { |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 939 | while (cfqq->next_rq) { |
| 940 | cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq); |
Tejun Heo | 1b5ed5e1 | 2005-11-10 08:49:19 +0100 | [diff] [blame] | 941 | dispatched++; |
| 942 | } |
| 943 | BUG_ON(!list_empty(&cfqq->fifo)); |
| 944 | } |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 945 | |
Tejun Heo | 1b5ed5e1 | 2005-11-10 08:49:19 +0100 | [diff] [blame] | 946 | return dispatched; |
| 947 | } |
| 948 | |
| 949 | static int |
| 950 | cfq_forced_dispatch(struct cfq_data *cfqd) |
| 951 | { |
| 952 | int i, dispatched = 0; |
| 953 | |
| 954 | for (i = 0; i < CFQ_PRIO_LISTS; i++) |
| 955 | dispatched += cfq_forced_dispatch_cfqqs(&cfqd->rr_list[i]); |
| 956 | |
| 957 | dispatched += cfq_forced_dispatch_cfqqs(&cfqd->busy_rr); |
| 958 | dispatched += cfq_forced_dispatch_cfqqs(&cfqd->cur_rr); |
| 959 | dispatched += cfq_forced_dispatch_cfqqs(&cfqd->idle_rr); |
| 960 | |
| 961 | cfq_slice_expired(cfqd, 0); |
| 962 | |
| 963 | BUG_ON(cfqd->busy_queues); |
| 964 | |
| 965 | return dispatched; |
| 966 | } |
| 967 | |
| 968 | static int |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 969 | cfq_dispatch_requests(request_queue_t *q, int force) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 970 | { |
| 971 | struct cfq_data *cfqd = q->elevator->elevator_data; |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 972 | struct cfq_queue *cfqq, *prev_cfqq; |
| 973 | int dispatched; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 974 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 975 | if (!cfqd->busy_queues) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 976 | return 0; |
| 977 | |
Tejun Heo | 1b5ed5e1 | 2005-11-10 08:49:19 +0100 | [diff] [blame] | 978 | if (unlikely(force)) |
| 979 | return cfq_forced_dispatch(cfqd); |
| 980 | |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 981 | dispatched = 0; |
| 982 | prev_cfqq = NULL; |
| 983 | while ((cfqq = cfq_select_queue(cfqd)) != NULL) { |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 984 | int max_dispatch; |
| 985 | |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 986 | /* |
| 987 | * Don't repeat dispatch from the previous queue. |
| 988 | */ |
| 989 | if (prev_cfqq == cfqq) |
| 990 | break; |
| 991 | |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 992 | cfq_clear_cfqq_must_dispatch(cfqq); |
| 993 | cfq_clear_cfqq_wait_request(cfqq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 994 | del_timer(&cfqd->idle_slice_timer); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 995 | |
Tejun Heo | 1b5ed5e1 | 2005-11-10 08:49:19 +0100 | [diff] [blame] | 996 | max_dispatch = cfqd->cfq_quantum; |
| 997 | if (cfq_class_idle(cfqq)) |
| 998 | max_dispatch = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 999 | |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 1000 | dispatched += __cfq_dispatch_requests(cfqd, cfqq, max_dispatch); |
| 1001 | |
| 1002 | /* |
| 1003 | * If the dispatch cfqq has idling enabled and is still |
| 1004 | * the active queue, break out. |
| 1005 | */ |
| 1006 | if (cfq_cfqq_idle_window(cfqq) && cfqd->active_queue) |
| 1007 | break; |
| 1008 | |
| 1009 | prev_cfqq = cfqq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1010 | } |
| 1011 | |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 1012 | return dispatched; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1013 | } |
| 1014 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1015 | /* |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 1016 | * task holds one reference to the queue, dropped when task exits. each rq |
| 1017 | * in-flight on this queue also holds a reference, dropped when rq is freed. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1018 | * |
| 1019 | * queue lock must be held here. |
| 1020 | */ |
| 1021 | static void cfq_put_queue(struct cfq_queue *cfqq) |
| 1022 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1023 | struct cfq_data *cfqd = cfqq->cfqd; |
| 1024 | |
| 1025 | BUG_ON(atomic_read(&cfqq->ref) <= 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1026 | |
| 1027 | if (!atomic_dec_and_test(&cfqq->ref)) |
| 1028 | return; |
| 1029 | |
| 1030 | BUG_ON(rb_first(&cfqq->sort_list)); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1031 | BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]); |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1032 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1033 | |
Jens Axboe | 7b14e3b | 2006-02-28 09:35:11 +0100 | [diff] [blame] | 1034 | if (unlikely(cfqd->active_queue == cfqq)) |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1035 | __cfq_slice_expired(cfqd, cfqq, 0); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1036 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1037 | /* |
| 1038 | * it's on the empty list and still hashed |
| 1039 | */ |
| 1040 | list_del(&cfqq->cfq_list); |
| 1041 | hlist_del(&cfqq->cfq_hash); |
| 1042 | kmem_cache_free(cfq_pool, cfqq); |
| 1043 | } |
| 1044 | |
Jens Axboe | 1ea25ecb | 2006-07-18 22:24:11 +0200 | [diff] [blame] | 1045 | static struct cfq_queue * |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1046 | __cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned int prio, |
| 1047 | const int hashval) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1048 | { |
| 1049 | struct hlist_head *hash_list = &cfqd->cfq_hash[hashval]; |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 1050 | struct hlist_node *entry; |
| 1051 | struct cfq_queue *__cfqq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1052 | |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 1053 | hlist_for_each_entry(__cfqq, entry, hash_list, cfq_hash) { |
Al Viro | b0a6916 | 2006-03-14 15:32:50 -0500 | [diff] [blame] | 1054 | const unsigned short __p = IOPRIO_PRIO_VALUE(__cfqq->org_ioprio_class, __cfqq->org_ioprio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1055 | |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 1056 | if (__cfqq->key == key && (__p == prio || !prio)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1057 | return __cfqq; |
| 1058 | } |
| 1059 | |
| 1060 | return NULL; |
| 1061 | } |
| 1062 | |
| 1063 | static struct cfq_queue * |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1064 | cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned short prio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1065 | { |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1066 | return __cfq_find_cfq_hash(cfqd, key, prio, hash_long(key, CFQ_QHASH_SHIFT)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1067 | } |
| 1068 | |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1069 | static void cfq_free_io_context(struct io_context *ioc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1070 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1071 | struct cfq_io_context *__cic; |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1072 | struct rb_node *n; |
| 1073 | int freed = 0; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1074 | |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1075 | while ((n = rb_first(&ioc->cic_root)) != NULL) { |
| 1076 | __cic = rb_entry(n, struct cfq_io_context, rb_node); |
| 1077 | rb_erase(&__cic->rb_node, &ioc->cic_root); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1078 | kmem_cache_free(cfq_ioc_pool, __cic); |
Al Viro | 334e94d | 2006-03-18 15:05:53 -0500 | [diff] [blame] | 1079 | freed++; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1080 | } |
| 1081 | |
Jens Axboe | 4050cf1 | 2006-07-19 05:07:12 +0200 | [diff] [blame] | 1082 | elv_ioc_count_mod(ioc_count, -freed); |
| 1083 | |
| 1084 | if (ioc_gone && !elv_ioc_count_read(ioc_count)) |
Al Viro | 334e94d | 2006-03-18 15:05:53 -0500 | [diff] [blame] | 1085 | complete(ioc_gone); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1086 | } |
| 1087 | |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 1088 | static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
| 1089 | { |
| 1090 | if (unlikely(cfqq == cfqd->active_queue)) |
| 1091 | __cfq_slice_expired(cfqd, cfqq, 0); |
| 1092 | |
| 1093 | cfq_put_queue(cfqq); |
| 1094 | } |
| 1095 | |
| 1096 | static void __cfq_exit_single_io_context(struct cfq_data *cfqd, |
| 1097 | struct cfq_io_context *cic) |
| 1098 | { |
Jens Axboe | fc46379 | 2006-08-29 09:05:44 +0200 | [diff] [blame] | 1099 | list_del_init(&cic->queue_list); |
| 1100 | smp_wmb(); |
| 1101 | cic->key = NULL; |
| 1102 | |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 1103 | if (cic->cfqq[ASYNC]) { |
| 1104 | cfq_exit_cfqq(cfqd, cic->cfqq[ASYNC]); |
| 1105 | cic->cfqq[ASYNC] = NULL; |
| 1106 | } |
| 1107 | |
| 1108 | if (cic->cfqq[SYNC]) { |
| 1109 | cfq_exit_cfqq(cfqd, cic->cfqq[SYNC]); |
| 1110 | cic->cfqq[SYNC] = NULL; |
| 1111 | } |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 1112 | } |
| 1113 | |
| 1114 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1115 | /* |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1116 | * Called with interrupts disabled |
| 1117 | */ |
| 1118 | static void cfq_exit_single_io_context(struct cfq_io_context *cic) |
| 1119 | { |
Al Viro | 478a82b | 2006-03-18 13:25:24 -0500 | [diff] [blame] | 1120 | struct cfq_data *cfqd = cic->key; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1121 | |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 1122 | if (cfqd) { |
| 1123 | request_queue_t *q = cfqd->queue; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1124 | |
Jens Axboe | fc46379 | 2006-08-29 09:05:44 +0200 | [diff] [blame] | 1125 | spin_lock_irq(q->queue_lock); |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 1126 | __cfq_exit_single_io_context(cfqd, cic); |
Jens Axboe | fc46379 | 2006-08-29 09:05:44 +0200 | [diff] [blame] | 1127 | spin_unlock_irq(q->queue_lock); |
Al Viro | 12a0573 | 2006-03-18 13:38:01 -0500 | [diff] [blame] | 1128 | } |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1129 | } |
| 1130 | |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1131 | static void cfq_exit_io_context(struct io_context *ioc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1132 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1133 | struct cfq_io_context *__cic; |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1134 | struct rb_node *n; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1135 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1136 | /* |
| 1137 | * put the reference this task is holding to the various queues |
| 1138 | */ |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1139 | |
| 1140 | n = rb_first(&ioc->cic_root); |
| 1141 | while (n != NULL) { |
| 1142 | __cic = rb_entry(n, struct cfq_io_context, rb_node); |
| 1143 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1144 | cfq_exit_single_io_context(__cic); |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1145 | n = rb_next(n); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1146 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1147 | } |
| 1148 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1149 | static struct cfq_io_context * |
Al Viro | 8267e26 | 2005-10-21 03:20:53 -0400 | [diff] [blame] | 1150 | cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1151 | { |
Jens Axboe | b5deef9 | 2006-07-19 23:39:40 +0200 | [diff] [blame] | 1152 | struct cfq_io_context *cic; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1153 | |
Jens Axboe | b5deef9 | 2006-07-19 23:39:40 +0200 | [diff] [blame] | 1154 | cic = kmem_cache_alloc_node(cfq_ioc_pool, gfp_mask, cfqd->queue->node); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1155 | if (cic) { |
Jens Axboe | 553698f | 2006-06-14 19:11:57 +0200 | [diff] [blame] | 1156 | memset(cic, 0, sizeof(*cic)); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1157 | cic->last_end_request = jiffies; |
Jens Axboe | 553698f | 2006-06-14 19:11:57 +0200 | [diff] [blame] | 1158 | INIT_LIST_HEAD(&cic->queue_list); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1159 | cic->dtor = cfq_free_io_context; |
| 1160 | cic->exit = cfq_exit_io_context; |
Jens Axboe | 4050cf1 | 2006-07-19 05:07:12 +0200 | [diff] [blame] | 1161 | elv_ioc_count_inc(ioc_count); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1162 | } |
| 1163 | |
| 1164 | return cic; |
| 1165 | } |
| 1166 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1167 | static void cfq_init_prio_data(struct cfq_queue *cfqq) |
| 1168 | { |
| 1169 | struct task_struct *tsk = current; |
| 1170 | int ioprio_class; |
| 1171 | |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1172 | if (!cfq_cfqq_prio_changed(cfqq)) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1173 | return; |
| 1174 | |
| 1175 | ioprio_class = IOPRIO_PRIO_CLASS(tsk->ioprio); |
| 1176 | switch (ioprio_class) { |
| 1177 | default: |
| 1178 | printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class); |
| 1179 | case IOPRIO_CLASS_NONE: |
| 1180 | /* |
| 1181 | * no prio set, place us in the middle of the BE classes |
| 1182 | */ |
| 1183 | cfqq->ioprio = task_nice_ioprio(tsk); |
| 1184 | cfqq->ioprio_class = IOPRIO_CLASS_BE; |
| 1185 | break; |
| 1186 | case IOPRIO_CLASS_RT: |
| 1187 | cfqq->ioprio = task_ioprio(tsk); |
| 1188 | cfqq->ioprio_class = IOPRIO_CLASS_RT; |
| 1189 | break; |
| 1190 | case IOPRIO_CLASS_BE: |
| 1191 | cfqq->ioprio = task_ioprio(tsk); |
| 1192 | cfqq->ioprio_class = IOPRIO_CLASS_BE; |
| 1193 | break; |
| 1194 | case IOPRIO_CLASS_IDLE: |
| 1195 | cfqq->ioprio_class = IOPRIO_CLASS_IDLE; |
| 1196 | cfqq->ioprio = 7; |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1197 | cfq_clear_cfqq_idle_window(cfqq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1198 | break; |
| 1199 | } |
| 1200 | |
| 1201 | /* |
| 1202 | * keep track of original prio settings in case we have to temporarily |
| 1203 | * elevate the priority of this queue |
| 1204 | */ |
| 1205 | cfqq->org_ioprio = cfqq->ioprio; |
| 1206 | cfqq->org_ioprio_class = cfqq->ioprio_class; |
| 1207 | |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1208 | if (cfq_cfqq_on_rr(cfqq)) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1209 | cfq_resort_rr_list(cfqq, 0); |
| 1210 | |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1211 | cfq_clear_cfqq_prio_changed(cfqq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1212 | } |
| 1213 | |
Al Viro | 478a82b | 2006-03-18 13:25:24 -0500 | [diff] [blame] | 1214 | static inline void changed_ioprio(struct cfq_io_context *cic) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1215 | { |
Al Viro | 478a82b | 2006-03-18 13:25:24 -0500 | [diff] [blame] | 1216 | struct cfq_data *cfqd = cic->key; |
| 1217 | struct cfq_queue *cfqq; |
Jens Axboe | 35e6077 | 2006-06-14 09:10:45 +0200 | [diff] [blame] | 1218 | |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 1219 | if (unlikely(!cfqd)) |
| 1220 | return; |
| 1221 | |
| 1222 | spin_lock(cfqd->queue->queue_lock); |
| 1223 | |
| 1224 | cfqq = cic->cfqq[ASYNC]; |
| 1225 | if (cfqq) { |
| 1226 | struct cfq_queue *new_cfqq; |
| 1227 | new_cfqq = cfq_get_queue(cfqd, CFQ_KEY_ASYNC, cic->ioc->task, |
| 1228 | GFP_ATOMIC); |
| 1229 | if (new_cfqq) { |
| 1230 | cic->cfqq[ASYNC] = new_cfqq; |
| 1231 | cfq_put_queue(cfqq); |
| 1232 | } |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1233 | } |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 1234 | |
| 1235 | cfqq = cic->cfqq[SYNC]; |
| 1236 | if (cfqq) |
| 1237 | cfq_mark_cfqq_prio_changed(cfqq); |
| 1238 | |
| 1239 | spin_unlock(cfqd->queue->queue_lock); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1240 | } |
| 1241 | |
Jens Axboe | fc46379 | 2006-08-29 09:05:44 +0200 | [diff] [blame] | 1242 | static void cfq_ioc_set_ioprio(struct io_context *ioc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1243 | { |
Al Viro | a6a0763 | 2006-03-18 13:26:44 -0500 | [diff] [blame] | 1244 | struct cfq_io_context *cic; |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1245 | struct rb_node *n; |
Al Viro | a6a0763 | 2006-03-18 13:26:44 -0500 | [diff] [blame] | 1246 | |
Jens Axboe | fc46379 | 2006-08-29 09:05:44 +0200 | [diff] [blame] | 1247 | ioc->ioprio_changed = 0; |
Al Viro | a6a0763 | 2006-03-18 13:26:44 -0500 | [diff] [blame] | 1248 | |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1249 | n = rb_first(&ioc->cic_root); |
| 1250 | while (n != NULL) { |
| 1251 | cic = rb_entry(n, struct cfq_io_context, rb_node); |
Jens Axboe | 3793c65 | 2006-05-30 21:11:04 +0200 | [diff] [blame] | 1252 | |
Al Viro | 478a82b | 2006-03-18 13:25:24 -0500 | [diff] [blame] | 1253 | changed_ioprio(cic); |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1254 | n = rb_next(n); |
| 1255 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1256 | } |
| 1257 | |
| 1258 | static struct cfq_queue * |
Al Viro | 6f325a1 | 2006-03-18 14:58:37 -0500 | [diff] [blame] | 1259 | cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk, |
Al Viro | 8267e26 | 2005-10-21 03:20:53 -0400 | [diff] [blame] | 1260 | gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1261 | { |
| 1262 | const int hashval = hash_long(key, CFQ_QHASH_SHIFT); |
| 1263 | struct cfq_queue *cfqq, *new_cfqq = NULL; |
Al Viro | 6f325a1 | 2006-03-18 14:58:37 -0500 | [diff] [blame] | 1264 | unsigned short ioprio; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1265 | |
| 1266 | retry: |
Al Viro | 6f325a1 | 2006-03-18 14:58:37 -0500 | [diff] [blame] | 1267 | ioprio = tsk->ioprio; |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1268 | cfqq = __cfq_find_cfq_hash(cfqd, key, ioprio, hashval); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1269 | |
| 1270 | if (!cfqq) { |
| 1271 | if (new_cfqq) { |
| 1272 | cfqq = new_cfqq; |
| 1273 | new_cfqq = NULL; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1274 | } else if (gfp_mask & __GFP_WAIT) { |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 1275 | /* |
| 1276 | * Inform the allocator of the fact that we will |
| 1277 | * just repeat this allocation if it fails, to allow |
| 1278 | * the allocator to do whatever it needs to attempt to |
| 1279 | * free memory. |
| 1280 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1281 | spin_unlock_irq(cfqd->queue->queue_lock); |
Jens Axboe | b5deef9 | 2006-07-19 23:39:40 +0200 | [diff] [blame] | 1282 | new_cfqq = kmem_cache_alloc_node(cfq_pool, gfp_mask|__GFP_NOFAIL, cfqd->queue->node); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1283 | spin_lock_irq(cfqd->queue->queue_lock); |
| 1284 | goto retry; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1285 | } else { |
Jens Axboe | b5deef9 | 2006-07-19 23:39:40 +0200 | [diff] [blame] | 1286 | cfqq = kmem_cache_alloc_node(cfq_pool, gfp_mask, cfqd->queue->node); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1287 | if (!cfqq) |
| 1288 | goto out; |
Kiyoshi Ueda | db3b584 | 2005-06-17 16:15:10 +0200 | [diff] [blame] | 1289 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1290 | |
| 1291 | memset(cfqq, 0, sizeof(*cfqq)); |
| 1292 | |
| 1293 | INIT_HLIST_NODE(&cfqq->cfq_hash); |
| 1294 | INIT_LIST_HEAD(&cfqq->cfq_list); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1295 | INIT_LIST_HEAD(&cfqq->fifo); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1296 | |
| 1297 | cfqq->key = key; |
| 1298 | hlist_add_head(&cfqq->cfq_hash, &cfqd->cfq_hash[hashval]); |
| 1299 | atomic_set(&cfqq->ref, 0); |
| 1300 | cfqq->cfqd = cfqd; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1301 | /* |
| 1302 | * set ->slice_left to allow preemption for a new process |
| 1303 | */ |
| 1304 | cfqq->slice_left = 2 * cfqd->cfq_slice_idle; |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 1305 | cfq_mark_cfqq_idle_window(cfqq); |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1306 | cfq_mark_cfqq_prio_changed(cfqq); |
Jens Axboe | 53b03744 | 2006-07-28 09:48:51 +0200 | [diff] [blame] | 1307 | cfq_mark_cfqq_queue_new(cfqq); |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1308 | cfq_init_prio_data(cfqq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1309 | } |
| 1310 | |
| 1311 | if (new_cfqq) |
| 1312 | kmem_cache_free(cfq_pool, new_cfqq); |
| 1313 | |
| 1314 | atomic_inc(&cfqq->ref); |
| 1315 | out: |
| 1316 | WARN_ON((gfp_mask & __GFP_WAIT) && !cfqq); |
| 1317 | return cfqq; |
| 1318 | } |
| 1319 | |
OGAWA Hirofumi | dbecf3a | 2006-04-18 09:45:18 +0200 | [diff] [blame] | 1320 | static void |
| 1321 | cfq_drop_dead_cic(struct io_context *ioc, struct cfq_io_context *cic) |
| 1322 | { |
Jens Axboe | fc46379 | 2006-08-29 09:05:44 +0200 | [diff] [blame] | 1323 | WARN_ON(!list_empty(&cic->queue_list)); |
OGAWA Hirofumi | dbecf3a | 2006-04-18 09:45:18 +0200 | [diff] [blame] | 1324 | rb_erase(&cic->rb_node, &ioc->cic_root); |
OGAWA Hirofumi | dbecf3a | 2006-04-18 09:45:18 +0200 | [diff] [blame] | 1325 | kmem_cache_free(cfq_ioc_pool, cic); |
Jens Axboe | 4050cf1 | 2006-07-19 05:07:12 +0200 | [diff] [blame] | 1326 | elv_ioc_count_dec(ioc_count); |
OGAWA Hirofumi | dbecf3a | 2006-04-18 09:45:18 +0200 | [diff] [blame] | 1327 | } |
| 1328 | |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1329 | static struct cfq_io_context * |
| 1330 | cfq_cic_rb_lookup(struct cfq_data *cfqd, struct io_context *ioc) |
| 1331 | { |
OGAWA Hirofumi | dbecf3a | 2006-04-18 09:45:18 +0200 | [diff] [blame] | 1332 | struct rb_node *n; |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1333 | struct cfq_io_context *cic; |
OGAWA Hirofumi | be3b075 | 2006-04-18 19:18:31 +0200 | [diff] [blame] | 1334 | void *k, *key = cfqd; |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1335 | |
OGAWA Hirofumi | dbecf3a | 2006-04-18 09:45:18 +0200 | [diff] [blame] | 1336 | restart: |
| 1337 | n = ioc->cic_root.rb_node; |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1338 | while (n) { |
| 1339 | cic = rb_entry(n, struct cfq_io_context, rb_node); |
OGAWA Hirofumi | be3b075 | 2006-04-18 19:18:31 +0200 | [diff] [blame] | 1340 | /* ->key must be copied to avoid race with cfq_exit_queue() */ |
| 1341 | k = cic->key; |
| 1342 | if (unlikely(!k)) { |
OGAWA Hirofumi | dbecf3a | 2006-04-18 09:45:18 +0200 | [diff] [blame] | 1343 | cfq_drop_dead_cic(ioc, cic); |
| 1344 | goto restart; |
| 1345 | } |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1346 | |
OGAWA Hirofumi | be3b075 | 2006-04-18 19:18:31 +0200 | [diff] [blame] | 1347 | if (key < k) |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1348 | n = n->rb_left; |
OGAWA Hirofumi | be3b075 | 2006-04-18 19:18:31 +0200 | [diff] [blame] | 1349 | else if (key > k) |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1350 | n = n->rb_right; |
| 1351 | else |
| 1352 | return cic; |
| 1353 | } |
| 1354 | |
| 1355 | return NULL; |
| 1356 | } |
| 1357 | |
| 1358 | static inline void |
| 1359 | cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc, |
| 1360 | struct cfq_io_context *cic) |
| 1361 | { |
OGAWA Hirofumi | dbecf3a | 2006-04-18 09:45:18 +0200 | [diff] [blame] | 1362 | struct rb_node **p; |
| 1363 | struct rb_node *parent; |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1364 | struct cfq_io_context *__cic; |
OGAWA Hirofumi | be3b075 | 2006-04-18 19:18:31 +0200 | [diff] [blame] | 1365 | void *k; |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1366 | |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1367 | cic->ioc = ioc; |
| 1368 | cic->key = cfqd; |
| 1369 | |
OGAWA Hirofumi | dbecf3a | 2006-04-18 09:45:18 +0200 | [diff] [blame] | 1370 | restart: |
| 1371 | parent = NULL; |
| 1372 | p = &ioc->cic_root.rb_node; |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1373 | while (*p) { |
| 1374 | parent = *p; |
| 1375 | __cic = rb_entry(parent, struct cfq_io_context, rb_node); |
OGAWA Hirofumi | be3b075 | 2006-04-18 19:18:31 +0200 | [diff] [blame] | 1376 | /* ->key must be copied to avoid race with cfq_exit_queue() */ |
| 1377 | k = __cic->key; |
| 1378 | if (unlikely(!k)) { |
Oleg Nesterov | be33c3a | 2006-08-21 08:36:12 +0200 | [diff] [blame] | 1379 | cfq_drop_dead_cic(ioc, __cic); |
OGAWA Hirofumi | dbecf3a | 2006-04-18 09:45:18 +0200 | [diff] [blame] | 1380 | goto restart; |
| 1381 | } |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1382 | |
OGAWA Hirofumi | be3b075 | 2006-04-18 19:18:31 +0200 | [diff] [blame] | 1383 | if (cic->key < k) |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1384 | p = &(*p)->rb_left; |
OGAWA Hirofumi | be3b075 | 2006-04-18 19:18:31 +0200 | [diff] [blame] | 1385 | else if (cic->key > k) |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1386 | p = &(*p)->rb_right; |
| 1387 | else |
| 1388 | BUG(); |
| 1389 | } |
| 1390 | |
| 1391 | rb_link_node(&cic->rb_node, parent, p); |
| 1392 | rb_insert_color(&cic->rb_node, &ioc->cic_root); |
Jens Axboe | fc46379 | 2006-08-29 09:05:44 +0200 | [diff] [blame] | 1393 | |
| 1394 | spin_lock_irq(cfqd->queue->queue_lock); |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1395 | list_add(&cic->queue_list, &cfqd->cic_list); |
Jens Axboe | fc46379 | 2006-08-29 09:05:44 +0200 | [diff] [blame] | 1396 | spin_unlock_irq(cfqd->queue->queue_lock); |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1397 | } |
| 1398 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1399 | /* |
| 1400 | * Setup general io context and cfq io context. There can be several cfq |
| 1401 | * io contexts per general io context, if this process is doing io to more |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1402 | * than one device managed by cfq. |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1403 | */ |
| 1404 | static struct cfq_io_context * |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1405 | cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1406 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1407 | struct io_context *ioc = NULL; |
| 1408 | struct cfq_io_context *cic; |
| 1409 | |
| 1410 | might_sleep_if(gfp_mask & __GFP_WAIT); |
| 1411 | |
Jens Axboe | b5deef9 | 2006-07-19 23:39:40 +0200 | [diff] [blame] | 1412 | ioc = get_io_context(gfp_mask, cfqd->queue->node); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1413 | if (!ioc) |
| 1414 | return NULL; |
| 1415 | |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1416 | cic = cfq_cic_rb_lookup(cfqd, ioc); |
| 1417 | if (cic) |
| 1418 | goto out; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1419 | |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1420 | cic = cfq_alloc_io_context(cfqd, gfp_mask); |
| 1421 | if (cic == NULL) |
| 1422 | goto err; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1423 | |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1424 | cfq_cic_link(cfqd, ioc, cic); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1425 | out: |
Jens Axboe | fc46379 | 2006-08-29 09:05:44 +0200 | [diff] [blame] | 1426 | smp_read_barrier_depends(); |
| 1427 | if (unlikely(ioc->ioprio_changed)) |
| 1428 | cfq_ioc_set_ioprio(ioc); |
| 1429 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1430 | return cic; |
| 1431 | err: |
| 1432 | put_io_context(ioc); |
| 1433 | return NULL; |
| 1434 | } |
| 1435 | |
| 1436 | static void |
| 1437 | cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic) |
| 1438 | { |
| 1439 | unsigned long elapsed, ttime; |
| 1440 | |
| 1441 | /* |
| 1442 | * if this context already has stuff queued, thinktime is from |
| 1443 | * last queue not last end |
| 1444 | */ |
| 1445 | #if 0 |
| 1446 | if (time_after(cic->last_end_request, cic->last_queue)) |
| 1447 | elapsed = jiffies - cic->last_end_request; |
| 1448 | else |
| 1449 | elapsed = jiffies - cic->last_queue; |
| 1450 | #else |
| 1451 | elapsed = jiffies - cic->last_end_request; |
| 1452 | #endif |
| 1453 | |
| 1454 | ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle); |
| 1455 | |
| 1456 | cic->ttime_samples = (7*cic->ttime_samples + 256) / 8; |
| 1457 | cic->ttime_total = (7*cic->ttime_total + 256*ttime) / 8; |
| 1458 | cic->ttime_mean = (cic->ttime_total + 128) / cic->ttime_samples; |
| 1459 | } |
| 1460 | |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 1461 | static void |
| 1462 | cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_io_context *cic, |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 1463 | struct request *rq) |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 1464 | { |
| 1465 | sector_t sdist; |
| 1466 | u64 total; |
| 1467 | |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 1468 | if (cic->last_request_pos < rq->sector) |
| 1469 | sdist = rq->sector - cic->last_request_pos; |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 1470 | else |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 1471 | sdist = cic->last_request_pos - rq->sector; |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 1472 | |
| 1473 | /* |
| 1474 | * Don't allow the seek distance to get too large from the |
| 1475 | * odd fragment, pagein, etc |
| 1476 | */ |
| 1477 | if (cic->seek_samples <= 60) /* second&third seek */ |
| 1478 | sdist = min(sdist, (cic->seek_mean * 4) + 2*1024*1024); |
| 1479 | else |
| 1480 | sdist = min(sdist, (cic->seek_mean * 4) + 2*1024*64); |
| 1481 | |
| 1482 | cic->seek_samples = (7*cic->seek_samples + 256) / 8; |
| 1483 | cic->seek_total = (7*cic->seek_total + (u64)256*sdist) / 8; |
| 1484 | total = cic->seek_total + (cic->seek_samples/2); |
| 1485 | do_div(total, cic->seek_samples); |
| 1486 | cic->seek_mean = (sector_t)total; |
| 1487 | } |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1488 | |
| 1489 | /* |
| 1490 | * Disable idle window if the process thinks too long or seeks so much that |
| 1491 | * it doesn't matter |
| 1492 | */ |
| 1493 | static void |
| 1494 | cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
| 1495 | struct cfq_io_context *cic) |
| 1496 | { |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1497 | int enable_idle = cfq_cfqq_idle_window(cfqq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1498 | |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 1499 | if (!cic->ioc->task || !cfqd->cfq_slice_idle || |
| 1500 | (cfqd->hw_tag && CIC_SEEKY(cic))) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1501 | enable_idle = 0; |
| 1502 | else if (sample_valid(cic->ttime_samples)) { |
| 1503 | if (cic->ttime_mean > cfqd->cfq_slice_idle) |
| 1504 | enable_idle = 0; |
| 1505 | else |
| 1506 | enable_idle = 1; |
| 1507 | } |
| 1508 | |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1509 | if (enable_idle) |
| 1510 | cfq_mark_cfqq_idle_window(cfqq); |
| 1511 | else |
| 1512 | cfq_clear_cfqq_idle_window(cfqq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1513 | } |
| 1514 | |
| 1515 | |
| 1516 | /* |
| 1517 | * Check if new_cfqq should preempt the currently active queue. Return 0 for |
| 1518 | * no or if we aren't sure, a 1 will cause a preempt. |
| 1519 | */ |
| 1520 | static int |
| 1521 | cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 1522 | struct request *rq) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1523 | { |
| 1524 | struct cfq_queue *cfqq = cfqd->active_queue; |
| 1525 | |
| 1526 | if (cfq_class_idle(new_cfqq)) |
| 1527 | return 0; |
| 1528 | |
| 1529 | if (!cfqq) |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 1530 | return 0; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1531 | |
| 1532 | if (cfq_class_idle(cfqq)) |
| 1533 | return 1; |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1534 | if (!cfq_cfqq_wait_request(new_cfqq)) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1535 | return 0; |
| 1536 | /* |
| 1537 | * if it doesn't have slice left, forget it |
| 1538 | */ |
| 1539 | if (new_cfqq->slice_left < cfqd->cfq_slice_idle) |
| 1540 | return 0; |
Jens Axboe | 374f84a | 2006-07-23 01:42:19 +0200 | [diff] [blame] | 1541 | /* |
| 1542 | * if the new request is sync, but the currently running queue is |
| 1543 | * not, let the sync request have priority. |
| 1544 | */ |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 1545 | if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq)) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1546 | return 1; |
Jens Axboe | 374f84a | 2006-07-23 01:42:19 +0200 | [diff] [blame] | 1547 | /* |
| 1548 | * So both queues are sync. Let the new request get disk time if |
| 1549 | * it's a metadata request and the current queue is doing regular IO. |
| 1550 | */ |
| 1551 | if (rq_is_meta(rq) && !cfqq->meta_pending) |
| 1552 | return 1; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1553 | |
| 1554 | return 0; |
| 1555 | } |
| 1556 | |
| 1557 | /* |
| 1558 | * cfqq preempts the active queue. if we allowed preempt with no slice left, |
| 1559 | * let it have half of its nominal slice. |
| 1560 | */ |
| 1561 | static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
| 1562 | { |
Jens Axboe | bf57225 | 2006-07-19 20:29:12 +0200 | [diff] [blame] | 1563 | cfq_slice_expired(cfqd, 1); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1564 | |
| 1565 | if (!cfqq->slice_left) |
| 1566 | cfqq->slice_left = cfq_prio_to_slice(cfqd, cfqq) / 2; |
| 1567 | |
Jens Axboe | bf57225 | 2006-07-19 20:29:12 +0200 | [diff] [blame] | 1568 | /* |
| 1569 | * Put the new queue at the front of the of the current list, |
| 1570 | * so we know that it will be selected next. |
| 1571 | */ |
| 1572 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
| 1573 | list_move(&cfqq->cfq_list, &cfqd->cur_rr); |
| 1574 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1575 | cfqq->slice_end = cfqq->slice_left + jiffies; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1576 | } |
| 1577 | |
| 1578 | /* |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 1579 | * Called when a new fs request (rq) is added (to cfqq). Check if there's |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1580 | * something we should do about it |
| 1581 | */ |
| 1582 | static void |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 1583 | cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
| 1584 | struct request *rq) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1585 | { |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 1586 | struct cfq_io_context *cic = RQ_CIC(rq); |
Jens Axboe | 12e9fdd | 2006-06-01 10:09:56 +0200 | [diff] [blame] | 1587 | |
Jens Axboe | 374f84a | 2006-07-23 01:42:19 +0200 | [diff] [blame] | 1588 | if (rq_is_meta(rq)) |
| 1589 | cfqq->meta_pending++; |
| 1590 | |
Jens Axboe | 9c2c38a | 2005-08-24 14:57:54 +0200 | [diff] [blame] | 1591 | /* |
Jens Axboe | 5380a10 | 2006-07-13 12:37:56 +0200 | [diff] [blame] | 1592 | * check if this request is a better next-serve candidate)) { |
Jens Axboe | 21183b0 | 2006-07-13 12:33:14 +0200 | [diff] [blame] | 1593 | */ |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 1594 | cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq); |
| 1595 | BUG_ON(!cfqq->next_rq); |
Jens Axboe | 21183b0 | 2006-07-13 12:33:14 +0200 | [diff] [blame] | 1596 | |
| 1597 | /* |
Jens Axboe | 9c2c38a | 2005-08-24 14:57:54 +0200 | [diff] [blame] | 1598 | * we never wait for an async request and we don't allow preemption |
| 1599 | * of an async request. so just return early |
| 1600 | */ |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 1601 | if (!rq_is_sync(rq)) { |
Jens Axboe | 12e9fdd | 2006-06-01 10:09:56 +0200 | [diff] [blame] | 1602 | /* |
| 1603 | * sync process issued an async request, if it's waiting |
| 1604 | * then expire it and kick rq handling. |
| 1605 | */ |
| 1606 | if (cic == cfqd->active_cic && |
| 1607 | del_timer(&cfqd->idle_slice_timer)) { |
| 1608 | cfq_slice_expired(cfqd, 0); |
Jens Axboe | dc72ef4 | 2006-07-20 14:54:05 +0200 | [diff] [blame] | 1609 | blk_start_queueing(cfqd->queue); |
Jens Axboe | 12e9fdd | 2006-06-01 10:09:56 +0200 | [diff] [blame] | 1610 | } |
Jens Axboe | 9c2c38a | 2005-08-24 14:57:54 +0200 | [diff] [blame] | 1611 | return; |
Jens Axboe | 12e9fdd | 2006-06-01 10:09:56 +0200 | [diff] [blame] | 1612 | } |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1613 | |
Jens Axboe | 9c2c38a | 2005-08-24 14:57:54 +0200 | [diff] [blame] | 1614 | cfq_update_io_thinktime(cfqd, cic); |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 1615 | cfq_update_io_seektime(cfqd, cic, rq); |
Jens Axboe | 9c2c38a | 2005-08-24 14:57:54 +0200 | [diff] [blame] | 1616 | cfq_update_idle_window(cfqd, cfqq, cic); |
| 1617 | |
| 1618 | cic->last_queue = jiffies; |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 1619 | cic->last_request_pos = rq->sector + rq->nr_sectors; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1620 | |
| 1621 | if (cfqq == cfqd->active_queue) { |
| 1622 | /* |
| 1623 | * if we are waiting for a request for this queue, let it rip |
| 1624 | * immediately and flag that we must not expire this queue |
| 1625 | * just now |
| 1626 | */ |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1627 | if (cfq_cfqq_wait_request(cfqq)) { |
| 1628 | cfq_mark_cfqq_must_dispatch(cfqq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1629 | del_timer(&cfqd->idle_slice_timer); |
Jens Axboe | dc72ef4 | 2006-07-20 14:54:05 +0200 | [diff] [blame] | 1630 | blk_start_queueing(cfqd->queue); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1631 | } |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 1632 | } else if (cfq_should_preempt(cfqd, cfqq, rq)) { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1633 | /* |
| 1634 | * not the active queue - expire current slice if it is |
| 1635 | * idle and has expired it's mean thinktime or this new queue |
| 1636 | * has some old slice time left and is of higher priority |
| 1637 | */ |
| 1638 | cfq_preempt_queue(cfqd, cfqq); |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1639 | cfq_mark_cfqq_must_dispatch(cfqq); |
Jens Axboe | dc72ef4 | 2006-07-20 14:54:05 +0200 | [diff] [blame] | 1640 | blk_start_queueing(cfqd->queue); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1641 | } |
| 1642 | } |
| 1643 | |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 1644 | static void cfq_insert_request(request_queue_t *q, struct request *rq) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1645 | { |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 1646 | struct cfq_data *cfqd = q->elevator->elevator_data; |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 1647 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1648 | |
| 1649 | cfq_init_prio_data(cfqq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1650 | |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 1651 | cfq_add_rq_rb(rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1652 | |
Jens Axboe | 21183b0 | 2006-07-13 12:33:14 +0200 | [diff] [blame] | 1653 | if (!cfq_cfqq_on_rr(cfqq)) |
| 1654 | cfq_add_cfqq_rr(cfqd, cfqq); |
| 1655 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1656 | list_add_tail(&rq->queuelist, &cfqq->fifo); |
| 1657 | |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 1658 | cfq_rq_enqueued(cfqd, cfqq, rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1659 | } |
| 1660 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1661 | static void cfq_completed_request(request_queue_t *q, struct request *rq) |
| 1662 | { |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 1663 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 1664 | struct cfq_data *cfqd = cfqq->cfqd; |
Jens Axboe | 5380a10 | 2006-07-13 12:37:56 +0200 | [diff] [blame] | 1665 | const int sync = rq_is_sync(rq); |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 1666 | unsigned long now; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1667 | |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 1668 | now = jiffies; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1669 | |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 1670 | WARN_ON(!cfqd->rq_in_driver); |
| 1671 | WARN_ON(!cfqq->on_dispatch[sync]); |
| 1672 | cfqd->rq_in_driver--; |
| 1673 | cfqq->on_dispatch[sync]--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1674 | |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 1675 | if (!cfq_class_idle(cfqq)) |
| 1676 | cfqd->last_end_request = now; |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1677 | |
Jens Axboe | 53b03744 | 2006-07-28 09:48:51 +0200 | [diff] [blame] | 1678 | if (!cfq_cfqq_dispatched(cfqq) && cfq_cfqq_on_rr(cfqq)) |
| 1679 | cfq_resort_rr_list(cfqq, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1680 | |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 1681 | if (sync) |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 1682 | RQ_CIC(rq)->last_end_request = now; |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 1683 | |
| 1684 | /* |
| 1685 | * If this is the active queue, check if it needs to be expired, |
| 1686 | * or if we want to idle in case it has no pending requests. |
| 1687 | */ |
| 1688 | if (cfqd->active_queue == cfqq) { |
| 1689 | if (time_after(now, cfqq->slice_end)) |
| 1690 | cfq_slice_expired(cfqd, 0); |
Jens Axboe | dd67d05 | 2006-06-21 09:36:18 +0200 | [diff] [blame] | 1691 | else if (sync && RB_EMPTY_ROOT(&cfqq->sort_list)) { |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 1692 | if (!cfq_arm_slice_timer(cfqd, cfqq)) |
| 1693 | cfq_schedule_dispatch(cfqd); |
| 1694 | } |
| 1695 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1696 | } |
| 1697 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1698 | /* |
| 1699 | * we temporarily boost lower priority queues if they are holding fs exclusive |
| 1700 | * resources. they are boosted to normal prio (CLASS_BE/4) |
| 1701 | */ |
| 1702 | static void cfq_prio_boost(struct cfq_queue *cfqq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1703 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1704 | const int ioprio_class = cfqq->ioprio_class; |
| 1705 | const int ioprio = cfqq->ioprio; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1706 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1707 | if (has_fs_excl()) { |
| 1708 | /* |
| 1709 | * boost idle prio on transactions that would lock out other |
| 1710 | * users of the filesystem |
| 1711 | */ |
| 1712 | if (cfq_class_idle(cfqq)) |
| 1713 | cfqq->ioprio_class = IOPRIO_CLASS_BE; |
| 1714 | if (cfqq->ioprio > IOPRIO_NORM) |
| 1715 | cfqq->ioprio = IOPRIO_NORM; |
| 1716 | } else { |
| 1717 | /* |
| 1718 | * check if we need to unboost the queue |
| 1719 | */ |
| 1720 | if (cfqq->ioprio_class != cfqq->org_ioprio_class) |
| 1721 | cfqq->ioprio_class = cfqq->org_ioprio_class; |
| 1722 | if (cfqq->ioprio != cfqq->org_ioprio) |
| 1723 | cfqq->ioprio = cfqq->org_ioprio; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1724 | } |
| 1725 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1726 | /* |
| 1727 | * refile between round-robin lists if we moved the priority class |
| 1728 | */ |
| 1729 | if ((ioprio_class != cfqq->ioprio_class || ioprio != cfqq->ioprio) && |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1730 | cfq_cfqq_on_rr(cfqq)) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1731 | cfq_resort_rr_list(cfqq, 0); |
| 1732 | } |
| 1733 | |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 1734 | static inline int __cfq_may_queue(struct cfq_queue *cfqq) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1735 | { |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1736 | if ((cfq_cfqq_wait_request(cfqq) || cfq_cfqq_must_alloc(cfqq)) && |
Andrew Morton | 99f95e5 | 2005-06-27 20:14:05 -0700 | [diff] [blame] | 1737 | !cfq_cfqq_must_alloc_slice(cfqq)) { |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1738 | cfq_mark_cfqq_must_alloc_slice(cfqq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1739 | return ELV_MQUEUE_MUST; |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1740 | } |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1741 | |
| 1742 | return ELV_MQUEUE_MAY; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1743 | } |
| 1744 | |
Jens Axboe | cb78b28 | 2006-07-28 09:32:57 +0200 | [diff] [blame] | 1745 | static int cfq_may_queue(request_queue_t *q, int rw) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1746 | { |
| 1747 | struct cfq_data *cfqd = q->elevator->elevator_data; |
| 1748 | struct task_struct *tsk = current; |
| 1749 | struct cfq_queue *cfqq; |
| 1750 | |
| 1751 | /* |
| 1752 | * don't force setup of a queue from here, as a call to may_queue |
| 1753 | * does not necessarily imply that a request actually will be queued. |
| 1754 | * so just lookup a possibly existing queue, or return 'may queue' |
| 1755 | * if that fails |
| 1756 | */ |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1757 | cfqq = cfq_find_cfq_hash(cfqd, cfq_queue_pid(tsk, rw), tsk->ioprio); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1758 | if (cfqq) { |
| 1759 | cfq_init_prio_data(cfqq); |
| 1760 | cfq_prio_boost(cfqq); |
| 1761 | |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 1762 | return __cfq_may_queue(cfqq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1763 | } |
| 1764 | |
| 1765 | return ELV_MQUEUE_MAY; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1766 | } |
| 1767 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1768 | /* |
| 1769 | * queue lock held here |
| 1770 | */ |
| 1771 | static void cfq_put_request(request_queue_t *q, struct request *rq) |
| 1772 | { |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 1773 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1774 | |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 1775 | if (cfqq) { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1776 | const int rw = rq_data_dir(rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1777 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1778 | BUG_ON(!cfqq->allocated[rw]); |
| 1779 | cfqq->allocated[rw]--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1780 | |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 1781 | put_io_context(RQ_CIC(rq)->ioc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1782 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1783 | rq->elevator_private = NULL; |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 1784 | rq->elevator_private2 = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1785 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1786 | cfq_put_queue(cfqq); |
| 1787 | } |
| 1788 | } |
| 1789 | |
| 1790 | /* |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1791 | * Allocate cfq data structures associated with this request. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1792 | */ |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1793 | static int |
Jens Axboe | cb78b28 | 2006-07-28 09:32:57 +0200 | [diff] [blame] | 1794 | cfq_set_request(request_queue_t *q, struct request *rq, gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1795 | { |
| 1796 | struct cfq_data *cfqd = q->elevator->elevator_data; |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1797 | struct task_struct *tsk = current; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1798 | struct cfq_io_context *cic; |
| 1799 | const int rw = rq_data_dir(rq); |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1800 | pid_t key = cfq_queue_pid(tsk, rw); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1801 | struct cfq_queue *cfqq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1802 | unsigned long flags; |
Al Viro | 12a0573 | 2006-03-18 13:38:01 -0500 | [diff] [blame] | 1803 | int is_sync = key != CFQ_KEY_ASYNC; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1804 | |
| 1805 | might_sleep_if(gfp_mask & __GFP_WAIT); |
| 1806 | |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1807 | cic = cfq_get_io_context(cfqd, gfp_mask); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1808 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1809 | spin_lock_irqsave(q->queue_lock, flags); |
| 1810 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1811 | if (!cic) |
| 1812 | goto queue_fail; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1813 | |
Al Viro | 12a0573 | 2006-03-18 13:38:01 -0500 | [diff] [blame] | 1814 | if (!cic->cfqq[is_sync]) { |
Al Viro | 6f325a1 | 2006-03-18 14:58:37 -0500 | [diff] [blame] | 1815 | cfqq = cfq_get_queue(cfqd, key, tsk, gfp_mask); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1816 | if (!cfqq) |
| 1817 | goto queue_fail; |
| 1818 | |
Al Viro | 12a0573 | 2006-03-18 13:38:01 -0500 | [diff] [blame] | 1819 | cic->cfqq[is_sync] = cfqq; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1820 | } else |
Al Viro | 12a0573 | 2006-03-18 13:38:01 -0500 | [diff] [blame] | 1821 | cfqq = cic->cfqq[is_sync]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1822 | |
| 1823 | cfqq->allocated[rw]++; |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1824 | cfq_clear_cfqq_must_alloc(cfqq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1825 | atomic_inc(&cfqq->ref); |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 1826 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1827 | spin_unlock_irqrestore(q->queue_lock, flags); |
| 1828 | |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 1829 | rq->elevator_private = cic; |
| 1830 | rq->elevator_private2 = cfqq; |
| 1831 | return 0; |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1832 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1833 | queue_fail: |
| 1834 | if (cic) |
| 1835 | put_io_context(cic->ioc); |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 1836 | |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1837 | cfq_schedule_dispatch(cfqd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1838 | spin_unlock_irqrestore(q->queue_lock, flags); |
| 1839 | return 1; |
| 1840 | } |
| 1841 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1842 | static void cfq_kick_queue(void *data) |
| 1843 | { |
| 1844 | request_queue_t *q = data; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1845 | unsigned long flags; |
| 1846 | |
| 1847 | spin_lock_irqsave(q->queue_lock, flags); |
Jens Axboe | dc72ef4 | 2006-07-20 14:54:05 +0200 | [diff] [blame] | 1848 | blk_start_queueing(q); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1849 | spin_unlock_irqrestore(q->queue_lock, flags); |
| 1850 | } |
| 1851 | |
| 1852 | /* |
| 1853 | * Timer running if the active_queue is currently idling inside its time slice |
| 1854 | */ |
| 1855 | static void cfq_idle_slice_timer(unsigned long data) |
| 1856 | { |
| 1857 | struct cfq_data *cfqd = (struct cfq_data *) data; |
| 1858 | struct cfq_queue *cfqq; |
| 1859 | unsigned long flags; |
| 1860 | |
| 1861 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); |
| 1862 | |
| 1863 | if ((cfqq = cfqd->active_queue) != NULL) { |
| 1864 | unsigned long now = jiffies; |
| 1865 | |
| 1866 | /* |
| 1867 | * expired |
| 1868 | */ |
| 1869 | if (time_after(now, cfqq->slice_end)) |
| 1870 | goto expire; |
| 1871 | |
| 1872 | /* |
| 1873 | * only expire and reinvoke request handler, if there are |
| 1874 | * other queues with pending requests |
| 1875 | */ |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 1876 | if (!cfqd->busy_queues) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1877 | goto out_cont; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1878 | |
| 1879 | /* |
| 1880 | * not expired and it has a request pending, let it dispatch |
| 1881 | */ |
Jens Axboe | dd67d05 | 2006-06-21 09:36:18 +0200 | [diff] [blame] | 1882 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) { |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1883 | cfq_mark_cfqq_must_dispatch(cfqq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1884 | goto out_kick; |
| 1885 | } |
| 1886 | } |
| 1887 | expire: |
| 1888 | cfq_slice_expired(cfqd, 0); |
| 1889 | out_kick: |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1890 | cfq_schedule_dispatch(cfqd); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1891 | out_cont: |
| 1892 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); |
| 1893 | } |
| 1894 | |
| 1895 | /* |
| 1896 | * Timer running if an idle class queue is waiting for service |
| 1897 | */ |
| 1898 | static void cfq_idle_class_timer(unsigned long data) |
| 1899 | { |
| 1900 | struct cfq_data *cfqd = (struct cfq_data *) data; |
| 1901 | unsigned long flags, end; |
| 1902 | |
| 1903 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); |
| 1904 | |
| 1905 | /* |
| 1906 | * race with a non-idle queue, reset timer |
| 1907 | */ |
| 1908 | end = cfqd->last_end_request + CFQ_IDLE_GRACE; |
Jens Axboe | ae818a3 | 2006-06-01 10:13:43 +0200 | [diff] [blame] | 1909 | if (!time_after_eq(jiffies, end)) |
| 1910 | mod_timer(&cfqd->idle_class_timer, end); |
| 1911 | else |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1912 | cfq_schedule_dispatch(cfqd); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1913 | |
| 1914 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); |
| 1915 | } |
| 1916 | |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1917 | static void cfq_shutdown_timer_wq(struct cfq_data *cfqd) |
| 1918 | { |
| 1919 | del_timer_sync(&cfqd->idle_slice_timer); |
| 1920 | del_timer_sync(&cfqd->idle_class_timer); |
| 1921 | blk_sync_queue(cfqd->queue); |
| 1922 | } |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1923 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1924 | static void cfq_exit_queue(elevator_t *e) |
| 1925 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1926 | struct cfq_data *cfqd = e->elevator_data; |
Al Viro | d9ff418 | 2006-03-18 13:51:22 -0500 | [diff] [blame] | 1927 | request_queue_t *q = cfqd->queue; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1928 | |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1929 | cfq_shutdown_timer_wq(cfqd); |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1930 | |
Al Viro | d9ff418 | 2006-03-18 13:51:22 -0500 | [diff] [blame] | 1931 | spin_lock_irq(q->queue_lock); |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1932 | |
Al Viro | d9ff418 | 2006-03-18 13:51:22 -0500 | [diff] [blame] | 1933 | if (cfqd->active_queue) |
| 1934 | __cfq_slice_expired(cfqd, cfqd->active_queue, 0); |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1935 | |
| 1936 | while (!list_empty(&cfqd->cic_list)) { |
Al Viro | d9ff418 | 2006-03-18 13:51:22 -0500 | [diff] [blame] | 1937 | struct cfq_io_context *cic = list_entry(cfqd->cic_list.next, |
| 1938 | struct cfq_io_context, |
| 1939 | queue_list); |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 1940 | |
| 1941 | __cfq_exit_single_io_context(cfqd, cic); |
Al Viro | d9ff418 | 2006-03-18 13:51:22 -0500 | [diff] [blame] | 1942 | } |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1943 | |
Al Viro | d9ff418 | 2006-03-18 13:51:22 -0500 | [diff] [blame] | 1944 | spin_unlock_irq(q->queue_lock); |
Al Viro | a90d742 | 2006-03-18 12:05:37 -0500 | [diff] [blame] | 1945 | |
| 1946 | cfq_shutdown_timer_wq(cfqd); |
| 1947 | |
Al Viro | a90d742 | 2006-03-18 12:05:37 -0500 | [diff] [blame] | 1948 | kfree(cfqd->cfq_hash); |
| 1949 | kfree(cfqd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1950 | } |
| 1951 | |
Jens Axboe | bc1c116 | 2006-06-08 08:49:06 +0200 | [diff] [blame] | 1952 | static void *cfq_init_queue(request_queue_t *q, elevator_t *e) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1953 | { |
| 1954 | struct cfq_data *cfqd; |
| 1955 | int i; |
| 1956 | |
Jens Axboe | b5deef9 | 2006-07-19 23:39:40 +0200 | [diff] [blame] | 1957 | cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL, q->node); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1958 | if (!cfqd) |
Jens Axboe | bc1c116 | 2006-06-08 08:49:06 +0200 | [diff] [blame] | 1959 | return NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1960 | |
| 1961 | memset(cfqd, 0, sizeof(*cfqd)); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1962 | |
| 1963 | for (i = 0; i < CFQ_PRIO_LISTS; i++) |
| 1964 | INIT_LIST_HEAD(&cfqd->rr_list[i]); |
| 1965 | |
| 1966 | INIT_LIST_HEAD(&cfqd->busy_rr); |
| 1967 | INIT_LIST_HEAD(&cfqd->cur_rr); |
| 1968 | INIT_LIST_HEAD(&cfqd->idle_rr); |
Al Viro | d9ff418 | 2006-03-18 13:51:22 -0500 | [diff] [blame] | 1969 | INIT_LIST_HEAD(&cfqd->cic_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1970 | |
Jens Axboe | b5deef9 | 2006-07-19 23:39:40 +0200 | [diff] [blame] | 1971 | cfqd->cfq_hash = kmalloc_node(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL, q->node); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1972 | if (!cfqd->cfq_hash) |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 1973 | goto out_free; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1974 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1975 | for (i = 0; i < CFQ_QHASH_ENTRIES; i++) |
| 1976 | INIT_HLIST_HEAD(&cfqd->cfq_hash[i]); |
| 1977 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1978 | cfqd->queue = q; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1979 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1980 | init_timer(&cfqd->idle_slice_timer); |
| 1981 | cfqd->idle_slice_timer.function = cfq_idle_slice_timer; |
| 1982 | cfqd->idle_slice_timer.data = (unsigned long) cfqd; |
| 1983 | |
| 1984 | init_timer(&cfqd->idle_class_timer); |
| 1985 | cfqd->idle_class_timer.function = cfq_idle_class_timer; |
| 1986 | cfqd->idle_class_timer.data = (unsigned long) cfqd; |
| 1987 | |
| 1988 | INIT_WORK(&cfqd->unplug_work, cfq_kick_queue, q); |
| 1989 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1990 | cfqd->cfq_quantum = cfq_quantum; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1991 | cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; |
| 1992 | cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1993 | cfqd->cfq_back_max = cfq_back_max; |
| 1994 | cfqd->cfq_back_penalty = cfq_back_penalty; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1995 | cfqd->cfq_slice[0] = cfq_slice_async; |
| 1996 | cfqd->cfq_slice[1] = cfq_slice_sync; |
| 1997 | cfqd->cfq_slice_async_rq = cfq_slice_async_rq; |
| 1998 | cfqd->cfq_slice_idle = cfq_slice_idle; |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1999 | |
Jens Axboe | bc1c116 | 2006-06-08 08:49:06 +0200 | [diff] [blame] | 2000 | return cfqd; |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 2001 | out_free: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2002 | kfree(cfqd); |
Jens Axboe | bc1c116 | 2006-06-08 08:49:06 +0200 | [diff] [blame] | 2003 | return NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2004 | } |
| 2005 | |
| 2006 | static void cfq_slab_kill(void) |
| 2007 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2008 | if (cfq_pool) |
| 2009 | kmem_cache_destroy(cfq_pool); |
| 2010 | if (cfq_ioc_pool) |
| 2011 | kmem_cache_destroy(cfq_ioc_pool); |
| 2012 | } |
| 2013 | |
| 2014 | static int __init cfq_slab_setup(void) |
| 2015 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2016 | cfq_pool = kmem_cache_create("cfq_pool", sizeof(struct cfq_queue), 0, 0, |
| 2017 | NULL, NULL); |
| 2018 | if (!cfq_pool) |
| 2019 | goto fail; |
| 2020 | |
| 2021 | cfq_ioc_pool = kmem_cache_create("cfq_ioc_pool", |
| 2022 | sizeof(struct cfq_io_context), 0, 0, NULL, NULL); |
| 2023 | if (!cfq_ioc_pool) |
| 2024 | goto fail; |
| 2025 | |
| 2026 | return 0; |
| 2027 | fail: |
| 2028 | cfq_slab_kill(); |
| 2029 | return -ENOMEM; |
| 2030 | } |
| 2031 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2032 | /* |
| 2033 | * sysfs parts below --> |
| 2034 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2035 | |
| 2036 | static ssize_t |
| 2037 | cfq_var_show(unsigned int var, char *page) |
| 2038 | { |
| 2039 | return sprintf(page, "%d\n", var); |
| 2040 | } |
| 2041 | |
| 2042 | static ssize_t |
| 2043 | cfq_var_store(unsigned int *var, const char *page, size_t count) |
| 2044 | { |
| 2045 | char *p = (char *) page; |
| 2046 | |
| 2047 | *var = simple_strtoul(p, &p, 10); |
| 2048 | return count; |
| 2049 | } |
| 2050 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2051 | #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 2052 | static ssize_t __FUNC(elevator_t *e, char *page) \ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2053 | { \ |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 2054 | struct cfq_data *cfqd = e->elevator_data; \ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2055 | unsigned int __data = __VAR; \ |
| 2056 | if (__CONV) \ |
| 2057 | __data = jiffies_to_msecs(__data); \ |
| 2058 | return cfq_var_show(__data, (page)); \ |
| 2059 | } |
| 2060 | SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2061 | SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1); |
| 2062 | SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1); |
Al Viro | e572ec7 | 2006-03-18 22:27:18 -0500 | [diff] [blame] | 2063 | SHOW_FUNCTION(cfq_back_seek_max_show, cfqd->cfq_back_max, 0); |
| 2064 | SHOW_FUNCTION(cfq_back_seek_penalty_show, cfqd->cfq_back_penalty, 0); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2065 | SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1); |
| 2066 | SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1); |
| 2067 | SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1); |
| 2068 | SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2069 | #undef SHOW_FUNCTION |
| 2070 | |
| 2071 | #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 2072 | static ssize_t __FUNC(elevator_t *e, const char *page, size_t count) \ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2073 | { \ |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 2074 | struct cfq_data *cfqd = e->elevator_data; \ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2075 | unsigned int __data; \ |
| 2076 | int ret = cfq_var_store(&__data, (page), count); \ |
| 2077 | if (__data < (MIN)) \ |
| 2078 | __data = (MIN); \ |
| 2079 | else if (__data > (MAX)) \ |
| 2080 | __data = (MAX); \ |
| 2081 | if (__CONV) \ |
| 2082 | *(__PTR) = msecs_to_jiffies(__data); \ |
| 2083 | else \ |
| 2084 | *(__PTR) = __data; \ |
| 2085 | return ret; \ |
| 2086 | } |
| 2087 | STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2088 | STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, UINT_MAX, 1); |
| 2089 | STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, UINT_MAX, 1); |
Al Viro | e572ec7 | 2006-03-18 22:27:18 -0500 | [diff] [blame] | 2090 | STORE_FUNCTION(cfq_back_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); |
| 2091 | STORE_FUNCTION(cfq_back_seek_penalty_store, &cfqd->cfq_back_penalty, 1, UINT_MAX, 0); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2092 | STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1); |
| 2093 | STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1); |
| 2094 | STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1); |
| 2095 | STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, UINT_MAX, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2096 | #undef STORE_FUNCTION |
| 2097 | |
Al Viro | e572ec7 | 2006-03-18 22:27:18 -0500 | [diff] [blame] | 2098 | #define CFQ_ATTR(name) \ |
| 2099 | __ATTR(name, S_IRUGO|S_IWUSR, cfq_##name##_show, cfq_##name##_store) |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 2100 | |
Al Viro | e572ec7 | 2006-03-18 22:27:18 -0500 | [diff] [blame] | 2101 | static struct elv_fs_entry cfq_attrs[] = { |
| 2102 | CFQ_ATTR(quantum), |
Al Viro | e572ec7 | 2006-03-18 22:27:18 -0500 | [diff] [blame] | 2103 | CFQ_ATTR(fifo_expire_sync), |
| 2104 | CFQ_ATTR(fifo_expire_async), |
| 2105 | CFQ_ATTR(back_seek_max), |
| 2106 | CFQ_ATTR(back_seek_penalty), |
| 2107 | CFQ_ATTR(slice_sync), |
| 2108 | CFQ_ATTR(slice_async), |
| 2109 | CFQ_ATTR(slice_async_rq), |
| 2110 | CFQ_ATTR(slice_idle), |
Al Viro | e572ec7 | 2006-03-18 22:27:18 -0500 | [diff] [blame] | 2111 | __ATTR_NULL |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2112 | }; |
| 2113 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2114 | static struct elevator_type iosched_cfq = { |
| 2115 | .ops = { |
| 2116 | .elevator_merge_fn = cfq_merge, |
| 2117 | .elevator_merged_fn = cfq_merged_request, |
| 2118 | .elevator_merge_req_fn = cfq_merged_requests, |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 2119 | .elevator_dispatch_fn = cfq_dispatch_requests, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2120 | .elevator_add_req_fn = cfq_insert_request, |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 2121 | .elevator_activate_req_fn = cfq_activate_request, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2122 | .elevator_deactivate_req_fn = cfq_deactivate_request, |
| 2123 | .elevator_queue_empty_fn = cfq_queue_empty, |
| 2124 | .elevator_completed_req_fn = cfq_completed_request, |
Jens Axboe | 21183b0 | 2006-07-13 12:33:14 +0200 | [diff] [blame] | 2125 | .elevator_former_req_fn = elv_rb_former_request, |
| 2126 | .elevator_latter_req_fn = elv_rb_latter_request, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2127 | .elevator_set_req_fn = cfq_set_request, |
| 2128 | .elevator_put_req_fn = cfq_put_request, |
| 2129 | .elevator_may_queue_fn = cfq_may_queue, |
| 2130 | .elevator_init_fn = cfq_init_queue, |
| 2131 | .elevator_exit_fn = cfq_exit_queue, |
Jens Axboe | fc46379 | 2006-08-29 09:05:44 +0200 | [diff] [blame] | 2132 | .trim = cfq_free_io_context, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2133 | }, |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 2134 | .elevator_attrs = cfq_attrs, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2135 | .elevator_name = "cfq", |
| 2136 | .elevator_owner = THIS_MODULE, |
| 2137 | }; |
| 2138 | |
| 2139 | static int __init cfq_init(void) |
| 2140 | { |
| 2141 | int ret; |
| 2142 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2143 | /* |
| 2144 | * could be 0 on HZ < 1000 setups |
| 2145 | */ |
| 2146 | if (!cfq_slice_async) |
| 2147 | cfq_slice_async = 1; |
| 2148 | if (!cfq_slice_idle) |
| 2149 | cfq_slice_idle = 1; |
| 2150 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2151 | if (cfq_slab_setup()) |
| 2152 | return -ENOMEM; |
| 2153 | |
| 2154 | ret = elv_register(&iosched_cfq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2155 | if (ret) |
| 2156 | cfq_slab_kill(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2157 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2158 | return ret; |
| 2159 | } |
| 2160 | |
| 2161 | static void __exit cfq_exit(void) |
| 2162 | { |
Peter Zijlstra | 6e9a473 | 2006-09-30 23:28:10 -0700 | [diff] [blame^] | 2163 | DECLARE_COMPLETION_ONSTACK(all_gone); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2164 | elv_unregister(&iosched_cfq); |
Al Viro | 334e94d | 2006-03-18 15:05:53 -0500 | [diff] [blame] | 2165 | ioc_gone = &all_gone; |
OGAWA Hirofumi | fba8227 | 2006-04-18 09:44:06 +0200 | [diff] [blame] | 2166 | /* ioc_gone's update must be visible before reading ioc_count */ |
| 2167 | smp_wmb(); |
Jens Axboe | 4050cf1 | 2006-07-19 05:07:12 +0200 | [diff] [blame] | 2168 | if (elv_ioc_count_read(ioc_count)) |
OGAWA Hirofumi | fba8227 | 2006-04-18 09:44:06 +0200 | [diff] [blame] | 2169 | wait_for_completion(ioc_gone); |
Al Viro | 334e94d | 2006-03-18 15:05:53 -0500 | [diff] [blame] | 2170 | synchronize_rcu(); |
Christoph Hellwig | 83521d3 | 2005-10-30 15:01:39 -0800 | [diff] [blame] | 2171 | cfq_slab_kill(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2172 | } |
| 2173 | |
| 2174 | module_init(cfq_init); |
| 2175 | module_exit(cfq_exit); |
| 2176 | |
| 2177 | MODULE_AUTHOR("Jens Axboe"); |
| 2178 | MODULE_LICENSE("GPL"); |
| 2179 | MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler"); |