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/rbtree.h> |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 13 | #include <linux/ioprio.h> |
Jens Axboe | 7b67913 | 2008-05-30 12:23:07 +0200 | [diff] [blame] | 14 | #include <linux/blktrace_api.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 15 | |
| 16 | /* |
| 17 | * tunables |
| 18 | */ |
Jens Axboe | fe094d9 | 2008-01-31 13:08:54 +0100 | [diff] [blame] | 19 | /* max queue in one round of service */ |
| 20 | static const int cfq_quantum = 4; |
Arjan van de Ven | 6410009 | 2006-01-06 09:46:02 +0100 | [diff] [blame] | 21 | static const int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 }; |
Jens Axboe | fe094d9 | 2008-01-31 13:08:54 +0100 | [diff] [blame] | 22 | /* maximum backwards seek, in KiB */ |
| 23 | static const int cfq_back_max = 16 * 1024; |
| 24 | /* penalty of a backwards seek */ |
| 25 | static const int cfq_back_penalty = 2; |
Arjan van de Ven | 6410009 | 2006-01-06 09:46:02 +0100 | [diff] [blame] | 26 | static const int cfq_slice_sync = HZ / 10; |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 27 | static int cfq_slice_async = HZ / 25; |
Arjan van de Ven | 6410009 | 2006-01-06 09:46:02 +0100 | [diff] [blame] | 28 | static const int cfq_slice_async_rq = 2; |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 29 | static int cfq_slice_idle = HZ / 125; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 30 | |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 31 | /* |
Jens Axboe | 0871714 | 2008-01-28 11:38:15 +0100 | [diff] [blame] | 32 | * offset from end of service tree |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 33 | */ |
Jens Axboe | 0871714 | 2008-01-28 11:38:15 +0100 | [diff] [blame] | 34 | #define CFQ_IDLE_DELAY (HZ / 5) |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 35 | |
| 36 | /* |
| 37 | * below this threshold, we consider thinktime immediate |
| 38 | */ |
| 39 | #define CFQ_MIN_TT (2) |
| 40 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 41 | #define CFQ_SLICE_SCALE (5) |
Aaron Carroll | 45333d5 | 2008-08-26 15:52:36 +0200 | [diff] [blame] | 42 | #define CFQ_HW_QUEUE_MIN (5) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 43 | |
Jens Axboe | fe094d9 | 2008-01-31 13:08:54 +0100 | [diff] [blame] | 44 | #define RQ_CIC(rq) \ |
| 45 | ((struct cfq_io_context *) (rq)->elevator_private) |
Jens Axboe | 7b67913 | 2008-05-30 12:23:07 +0200 | [diff] [blame] | 46 | #define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elevator_private2) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 47 | |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 48 | static struct kmem_cache *cfq_pool; |
| 49 | static struct kmem_cache *cfq_ioc_pool; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 50 | |
Jens Axboe | 4050cf1 | 2006-07-19 05:07:12 +0200 | [diff] [blame] | 51 | static DEFINE_PER_CPU(unsigned long, ioc_count); |
Al Viro | 334e94d | 2006-03-18 15:05:53 -0500 | [diff] [blame] | 52 | static struct completion *ioc_gone; |
Jens Axboe | 9a11b4e | 2008-05-29 09:32:08 +0200 | [diff] [blame] | 53 | static DEFINE_SPINLOCK(ioc_gone_lock); |
Al Viro | 334e94d | 2006-03-18 15:05:53 -0500 | [diff] [blame] | 54 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 55 | #define CFQ_PRIO_LISTS IOPRIO_BE_NR |
| 56 | #define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 57 | #define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT) |
| 58 | |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 59 | #define sample_valid(samples) ((samples) > 80) |
| 60 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 61 | /* |
Jens Axboe | cc09e29 | 2007-04-26 12:53:50 +0200 | [diff] [blame] | 62 | * Most of our rbtree usage is for sorting with min extraction, so |
| 63 | * if we cache the leftmost node we don't have to walk down the tree |
| 64 | * to find it. Idea borrowed from Ingo Molnars CFS scheduler. We should |
| 65 | * move this into the elevator for the rq sorting as well. |
| 66 | */ |
| 67 | struct cfq_rb_root { |
| 68 | struct rb_root rb; |
| 69 | struct rb_node *left; |
| 70 | }; |
| 71 | #define CFQ_RB_ROOT (struct cfq_rb_root) { RB_ROOT, NULL, } |
| 72 | |
| 73 | /* |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 74 | * Per block device queue structure |
| 75 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 76 | struct cfq_data { |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 77 | struct request_queue *queue; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 78 | |
| 79 | /* |
| 80 | * rr list of queues with requests and the count of them |
| 81 | */ |
Jens Axboe | cc09e29 | 2007-04-26 12:53:50 +0200 | [diff] [blame] | 82 | struct cfq_rb_root service_tree; |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 83 | |
| 84 | /* |
| 85 | * Each priority tree is sorted by next_request position. These |
| 86 | * trees are used when determining if two or more queues are |
| 87 | * interleaving requests (see cfq_close_cooperator). |
| 88 | */ |
| 89 | struct rb_root prio_trees[CFQ_PRIO_LISTS]; |
| 90 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 91 | unsigned int busy_queues; |
Divyesh Shah | 3a9a3f6 | 2009-01-30 12:46:41 +0100 | [diff] [blame] | 92 | /* |
| 93 | * Used to track any pending rt requests so we can pre-empt current |
| 94 | * non-RT cfqq in service when this value is non-zero. |
| 95 | */ |
| 96 | unsigned int busy_rt_queues; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 97 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 98 | int rq_in_driver; |
Jens Axboe | 3ed9a29 | 2007-04-23 08:33:33 +0200 | [diff] [blame] | 99 | int sync_flight; |
Aaron Carroll | 45333d5 | 2008-08-26 15:52:36 +0200 | [diff] [blame] | 100 | |
| 101 | /* |
| 102 | * queue-depth detection |
| 103 | */ |
| 104 | int rq_queued; |
Jens Axboe | 25776e3 | 2006-06-01 10:12:26 +0200 | [diff] [blame] | 105 | int hw_tag; |
Aaron Carroll | 45333d5 | 2008-08-26 15:52:36 +0200 | [diff] [blame] | 106 | int hw_tag_samples; |
| 107 | int rq_in_driver_peak; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 108 | |
| 109 | /* |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 110 | * idle window management |
| 111 | */ |
| 112 | struct timer_list idle_slice_timer; |
| 113 | struct work_struct unplug_work; |
| 114 | |
| 115 | struct cfq_queue *active_queue; |
| 116 | struct cfq_io_context *active_cic; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 117 | |
Vasily Tarasov | c2dea2d | 2007-07-20 10:06:38 +0200 | [diff] [blame] | 118 | /* |
| 119 | * async queue for each priority case |
| 120 | */ |
| 121 | struct cfq_queue *async_cfqq[2][IOPRIO_BE_NR]; |
| 122 | struct cfq_queue *async_idle_cfqq; |
Jens Axboe | 15c31be | 2007-07-10 13:43:25 +0200 | [diff] [blame] | 123 | |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 124 | sector_t last_position; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 125 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 126 | /* |
| 127 | * tunables, see top of file |
| 128 | */ |
| 129 | unsigned int cfq_quantum; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 130 | unsigned int cfq_fifo_expire[2]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 131 | unsigned int cfq_back_penalty; |
| 132 | unsigned int cfq_back_max; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 133 | unsigned int cfq_slice[2]; |
| 134 | unsigned int cfq_slice_async_rq; |
| 135 | unsigned int cfq_slice_idle; |
Al Viro | d9ff418 | 2006-03-18 13:51:22 -0500 | [diff] [blame] | 136 | |
| 137 | struct list_head cic_list; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 138 | }; |
| 139 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 140 | /* |
| 141 | * Per process-grouping structure |
| 142 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 143 | struct cfq_queue { |
| 144 | /* reference count */ |
| 145 | atomic_t ref; |
Richard Kennedy | be754d2 | 2008-05-23 06:52:00 +0200 | [diff] [blame] | 146 | /* various state flags, see below */ |
| 147 | unsigned int flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 148 | /* parent cfq_data */ |
| 149 | struct cfq_data *cfqd; |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 150 | /* service_tree member */ |
| 151 | struct rb_node rb_node; |
| 152 | /* service_tree key */ |
| 153 | unsigned long rb_key; |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 154 | /* prio tree member */ |
| 155 | struct rb_node p_node; |
Jens Axboe | f2d1f0a | 2009-04-23 12:19:38 +0200 | [diff] [blame] | 156 | /* prio tree root we belong to, if any */ |
| 157 | struct rb_root *p_root; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 158 | /* sorted list of pending requests */ |
| 159 | struct rb_root sort_list; |
| 160 | /* if fifo isn't expired, next request to serve */ |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 161 | struct request *next_rq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 162 | /* requests queued in sort_list */ |
| 163 | int queued[2]; |
| 164 | /* currently allocated requests */ |
| 165 | int allocated[2]; |
| 166 | /* fifo list of requests in sort_list */ |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 167 | struct list_head fifo; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 168 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 169 | unsigned long slice_end; |
Jens Axboe | c5b680f | 2007-01-19 11:56:49 +1100 | [diff] [blame] | 170 | long slice_resid; |
Jens Axboe | 2f5cb73 | 2009-04-07 08:51:19 +0200 | [diff] [blame] | 171 | unsigned int slice_dispatch; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 172 | |
Richard Kennedy | be754d2 | 2008-05-23 06:52:00 +0200 | [diff] [blame] | 173 | /* pending metadata requests */ |
| 174 | int meta_pending; |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 175 | /* number of requests that are on the dispatch list or inside driver */ |
| 176 | int dispatched; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 177 | |
| 178 | /* io prio of this group */ |
| 179 | unsigned short ioprio, org_ioprio; |
| 180 | unsigned short ioprio_class, org_ioprio_class; |
| 181 | |
Jens Axboe | 7b67913 | 2008-05-30 12:23:07 +0200 | [diff] [blame] | 182 | pid_t pid; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 183 | }; |
| 184 | |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 185 | enum cfqq_state_flags { |
Jens Axboe | b0b8d749 | 2007-01-19 11:35:30 +1100 | [diff] [blame] | 186 | CFQ_CFQQ_FLAG_on_rr = 0, /* on round-robin busy list */ |
| 187 | CFQ_CFQQ_FLAG_wait_request, /* waiting for a request */ |
Jens Axboe | b029195 | 2009-04-07 11:38:31 +0200 | [diff] [blame] | 188 | CFQ_CFQQ_FLAG_must_dispatch, /* must be allowed a dispatch */ |
Jens Axboe | b0b8d749 | 2007-01-19 11:35:30 +1100 | [diff] [blame] | 189 | CFQ_CFQQ_FLAG_must_alloc, /* must be allowed rq alloc */ |
| 190 | CFQ_CFQQ_FLAG_must_alloc_slice, /* per-slice must_alloc flag */ |
Jens Axboe | b0b8d749 | 2007-01-19 11:35:30 +1100 | [diff] [blame] | 191 | CFQ_CFQQ_FLAG_fifo_expire, /* FIFO checked in this slice */ |
| 192 | CFQ_CFQQ_FLAG_idle_window, /* slice idling enabled */ |
| 193 | CFQ_CFQQ_FLAG_prio_changed, /* task priority has changed */ |
Jens Axboe | 44f7c16 | 2007-01-19 11:51:58 +1100 | [diff] [blame] | 194 | CFQ_CFQQ_FLAG_slice_new, /* no requests dispatched in slice */ |
Vasily Tarasov | 91fac31 | 2007-04-25 12:29:51 +0200 | [diff] [blame] | 195 | CFQ_CFQQ_FLAG_sync, /* synchronous queue */ |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 196 | CFQ_CFQQ_FLAG_coop, /* has done a coop jump of the queue */ |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 197 | }; |
| 198 | |
| 199 | #define CFQ_CFQQ_FNS(name) \ |
| 200 | static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \ |
| 201 | { \ |
Jens Axboe | fe094d9 | 2008-01-31 13:08:54 +0100 | [diff] [blame] | 202 | (cfqq)->flags |= (1 << CFQ_CFQQ_FLAG_##name); \ |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 203 | } \ |
| 204 | static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \ |
| 205 | { \ |
Jens Axboe | fe094d9 | 2008-01-31 13:08:54 +0100 | [diff] [blame] | 206 | (cfqq)->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \ |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 207 | } \ |
| 208 | static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \ |
| 209 | { \ |
Jens Axboe | fe094d9 | 2008-01-31 13:08:54 +0100 | [diff] [blame] | 210 | return ((cfqq)->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \ |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 211 | } |
| 212 | |
| 213 | CFQ_CFQQ_FNS(on_rr); |
| 214 | CFQ_CFQQ_FNS(wait_request); |
Jens Axboe | b029195 | 2009-04-07 11:38:31 +0200 | [diff] [blame] | 215 | CFQ_CFQQ_FNS(must_dispatch); |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 216 | CFQ_CFQQ_FNS(must_alloc); |
| 217 | CFQ_CFQQ_FNS(must_alloc_slice); |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 218 | CFQ_CFQQ_FNS(fifo_expire); |
| 219 | CFQ_CFQQ_FNS(idle_window); |
| 220 | CFQ_CFQQ_FNS(prio_changed); |
Jens Axboe | 44f7c16 | 2007-01-19 11:51:58 +1100 | [diff] [blame] | 221 | CFQ_CFQQ_FNS(slice_new); |
Vasily Tarasov | 91fac31 | 2007-04-25 12:29:51 +0200 | [diff] [blame] | 222 | CFQ_CFQQ_FNS(sync); |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 223 | CFQ_CFQQ_FNS(coop); |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 224 | #undef CFQ_CFQQ_FNS |
| 225 | |
Jens Axboe | 7b67913 | 2008-05-30 12:23:07 +0200 | [diff] [blame] | 226 | #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \ |
| 227 | blk_add_trace_msg((cfqd)->queue, "cfq%d " fmt, (cfqq)->pid, ##args) |
| 228 | #define cfq_log(cfqd, fmt, args...) \ |
| 229 | blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args) |
| 230 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 231 | static void cfq_dispatch_insert(struct request_queue *, struct request *); |
Vasily Tarasov | 91fac31 | 2007-04-25 12:29:51 +0200 | [diff] [blame] | 232 | static struct cfq_queue *cfq_get_queue(struct cfq_data *, int, |
Jens Axboe | fd0928d | 2008-01-24 08:52:45 +0100 | [diff] [blame] | 233 | struct io_context *, gfp_t); |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 234 | static struct cfq_io_context *cfq_cic_lookup(struct cfq_data *, |
Vasily Tarasov | 91fac31 | 2007-04-25 12:29:51 +0200 | [diff] [blame] | 235 | struct io_context *); |
| 236 | |
| 237 | static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_context *cic, |
| 238 | int is_sync) |
| 239 | { |
| 240 | return cic->cfqq[!!is_sync]; |
| 241 | } |
| 242 | |
| 243 | static inline void cic_set_cfqq(struct cfq_io_context *cic, |
| 244 | struct cfq_queue *cfqq, int is_sync) |
| 245 | { |
| 246 | cic->cfqq[!!is_sync] = cfqq; |
| 247 | } |
| 248 | |
| 249 | /* |
| 250 | * We regard a request as SYNC, if it's either a read or has the SYNC bit |
| 251 | * set (in which case it could also be direct WRITE). |
| 252 | */ |
| 253 | static inline int cfq_bio_sync(struct bio *bio) |
| 254 | { |
| 255 | if (bio_data_dir(bio) == READ || bio_sync(bio)) |
| 256 | return 1; |
| 257 | |
| 258 | return 0; |
| 259 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 260 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 261 | /* |
Andrew Morton | 99f95e5 | 2005-06-27 20:14:05 -0700 | [diff] [blame] | 262 | * scheduler run of queue, if there are requests pending and no one in the |
| 263 | * driver that will restart queueing |
| 264 | */ |
| 265 | static inline void cfq_schedule_dispatch(struct cfq_data *cfqd) |
| 266 | { |
Jens Axboe | 7b67913 | 2008-05-30 12:23:07 +0200 | [diff] [blame] | 267 | if (cfqd->busy_queues) { |
| 268 | cfq_log(cfqd, "schedule dispatch"); |
Jens Axboe | 18887ad | 2008-07-28 13:08:45 +0200 | [diff] [blame] | 269 | kblockd_schedule_work(cfqd->queue, &cfqd->unplug_work); |
Jens Axboe | 7b67913 | 2008-05-30 12:23:07 +0200 | [diff] [blame] | 270 | } |
Andrew Morton | 99f95e5 | 2005-06-27 20:14:05 -0700 | [diff] [blame] | 271 | } |
| 272 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 273 | static int cfq_queue_empty(struct request_queue *q) |
Andrew Morton | 99f95e5 | 2005-06-27 20:14:05 -0700 | [diff] [blame] | 274 | { |
| 275 | struct cfq_data *cfqd = q->elevator->elevator_data; |
| 276 | |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 277 | return !cfqd->busy_queues; |
Andrew Morton | 99f95e5 | 2005-06-27 20:14:05 -0700 | [diff] [blame] | 278 | } |
| 279 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 280 | /* |
Jens Axboe | 44f7c16 | 2007-01-19 11:51:58 +1100 | [diff] [blame] | 281 | * Scale schedule slice based on io priority. Use the sync time slice only |
| 282 | * if a queue is marked sync and has sync io queued. A sync queue with async |
| 283 | * io only, should not get full sync slice length. |
| 284 | */ |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 285 | static inline int cfq_prio_slice(struct cfq_data *cfqd, int sync, |
| 286 | unsigned short prio) |
| 287 | { |
| 288 | const int base_slice = cfqd->cfq_slice[sync]; |
| 289 | |
| 290 | WARN_ON(prio >= IOPRIO_BE_NR); |
| 291 | |
| 292 | return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - prio)); |
| 293 | } |
| 294 | |
Jens Axboe | 44f7c16 | 2007-01-19 11:51:58 +1100 | [diff] [blame] | 295 | static inline int |
| 296 | cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
| 297 | { |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 298 | return cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio); |
Jens Axboe | 44f7c16 | 2007-01-19 11:51:58 +1100 | [diff] [blame] | 299 | } |
| 300 | |
| 301 | static inline void |
| 302 | cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
| 303 | { |
| 304 | cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies; |
Jens Axboe | 7b67913 | 2008-05-30 12:23:07 +0200 | [diff] [blame] | 305 | cfq_log_cfqq(cfqd, cfqq, "set_slice=%lu", cfqq->slice_end - jiffies); |
Jens Axboe | 44f7c16 | 2007-01-19 11:51:58 +1100 | [diff] [blame] | 306 | } |
| 307 | |
| 308 | /* |
| 309 | * We need to wrap this check in cfq_cfqq_slice_new(), since ->slice_end |
| 310 | * isn't valid until the first request from the dispatch is activated |
| 311 | * and the slice time set. |
| 312 | */ |
| 313 | static inline int cfq_slice_used(struct cfq_queue *cfqq) |
| 314 | { |
| 315 | if (cfq_cfqq_slice_new(cfqq)) |
| 316 | return 0; |
| 317 | if (time_before(jiffies, cfqq->slice_end)) |
| 318 | return 0; |
| 319 | |
| 320 | return 1; |
| 321 | } |
| 322 | |
| 323 | /* |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 324 | * 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] | 325 | * 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] | 326 | * behind the head is penalized and only allowed to a certain extent. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 327 | */ |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 328 | static struct request * |
| 329 | 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] | 330 | { |
| 331 | sector_t last, s1, s2, d1 = 0, d2 = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 332 | unsigned long back_max; |
Andreas Mohr | e8a9905 | 2006-03-28 08:59:49 +0200 | [diff] [blame] | 333 | #define CFQ_RQ1_WRAP 0x01 /* request 1 wraps */ |
| 334 | #define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */ |
| 335 | unsigned wrap = 0; /* bit mask: requests behind the disk head? */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 336 | |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 337 | if (rq1 == NULL || rq1 == rq2) |
| 338 | return rq2; |
| 339 | if (rq2 == NULL) |
| 340 | return rq1; |
Jens Axboe | 9c2c38a | 2005-08-24 14:57:54 +0200 | [diff] [blame] | 341 | |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 342 | if (rq_is_sync(rq1) && !rq_is_sync(rq2)) |
| 343 | return rq1; |
| 344 | else if (rq_is_sync(rq2) && !rq_is_sync(rq1)) |
| 345 | return rq2; |
Jens Axboe | 374f84a | 2006-07-23 01:42:19 +0200 | [diff] [blame] | 346 | if (rq_is_meta(rq1) && !rq_is_meta(rq2)) |
| 347 | return rq1; |
| 348 | else if (rq_is_meta(rq2) && !rq_is_meta(rq1)) |
| 349 | return rq2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 350 | |
Tejun Heo | 83096eb | 2009-05-07 22:24:39 +0900 | [diff] [blame] | 351 | s1 = blk_rq_pos(rq1); |
| 352 | s2 = blk_rq_pos(rq2); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 353 | |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 354 | last = cfqd->last_position; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 355 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 356 | /* |
| 357 | * by definition, 1KiB is 2 sectors |
| 358 | */ |
| 359 | back_max = cfqd->cfq_back_max * 2; |
| 360 | |
| 361 | /* |
| 362 | * Strict one way elevator _except_ in the case where we allow |
| 363 | * short backward seeks which are biased as twice the cost of a |
| 364 | * similar forward seek. |
| 365 | */ |
| 366 | if (s1 >= last) |
| 367 | d1 = s1 - last; |
| 368 | else if (s1 + back_max >= last) |
| 369 | d1 = (last - s1) * cfqd->cfq_back_penalty; |
| 370 | else |
Andreas Mohr | e8a9905 | 2006-03-28 08:59:49 +0200 | [diff] [blame] | 371 | wrap |= CFQ_RQ1_WRAP; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 372 | |
| 373 | if (s2 >= last) |
| 374 | d2 = s2 - last; |
| 375 | else if (s2 + back_max >= last) |
| 376 | d2 = (last - s2) * cfqd->cfq_back_penalty; |
| 377 | else |
Andreas Mohr | e8a9905 | 2006-03-28 08:59:49 +0200 | [diff] [blame] | 378 | wrap |= CFQ_RQ2_WRAP; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 379 | |
| 380 | /* Found required data */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 381 | |
Andreas Mohr | e8a9905 | 2006-03-28 08:59:49 +0200 | [diff] [blame] | 382 | /* |
| 383 | * By doing switch() on the bit mask "wrap" we avoid having to |
| 384 | * check two variables for all permutations: --> faster! |
| 385 | */ |
| 386 | switch (wrap) { |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 387 | case 0: /* common case for CFQ: rq1 and rq2 not wrapped */ |
Andreas Mohr | e8a9905 | 2006-03-28 08:59:49 +0200 | [diff] [blame] | 388 | if (d1 < d2) |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 389 | return rq1; |
Andreas Mohr | e8a9905 | 2006-03-28 08:59:49 +0200 | [diff] [blame] | 390 | else if (d2 < d1) |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 391 | return rq2; |
Andreas Mohr | e8a9905 | 2006-03-28 08:59:49 +0200 | [diff] [blame] | 392 | else { |
| 393 | if (s1 >= s2) |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 394 | return rq1; |
Andreas Mohr | e8a9905 | 2006-03-28 08:59:49 +0200 | [diff] [blame] | 395 | else |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 396 | return rq2; |
Andreas Mohr | e8a9905 | 2006-03-28 08:59:49 +0200 | [diff] [blame] | 397 | } |
| 398 | |
| 399 | case CFQ_RQ2_WRAP: |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 400 | return rq1; |
Andreas Mohr | e8a9905 | 2006-03-28 08:59:49 +0200 | [diff] [blame] | 401 | case CFQ_RQ1_WRAP: |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 402 | return rq2; |
| 403 | case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both rqs wrapped */ |
Andreas Mohr | e8a9905 | 2006-03-28 08:59:49 +0200 | [diff] [blame] | 404 | default: |
| 405 | /* |
| 406 | * Since both rqs are wrapped, |
| 407 | * start with the one that's further behind head |
| 408 | * (--> only *one* back seek required), |
| 409 | * since back seek takes more time than forward. |
| 410 | */ |
| 411 | if (s1 <= s2) |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 412 | return rq1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 413 | else |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 414 | return rq2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 415 | } |
| 416 | } |
| 417 | |
Jens Axboe | 498d3aa2 | 2007-04-26 12:54:48 +0200 | [diff] [blame] | 418 | /* |
| 419 | * The below is leftmost cache rbtree addon |
| 420 | */ |
Jens Axboe | 0871714 | 2008-01-28 11:38:15 +0100 | [diff] [blame] | 421 | static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root) |
Jens Axboe | cc09e29 | 2007-04-26 12:53:50 +0200 | [diff] [blame] | 422 | { |
| 423 | if (!root->left) |
| 424 | root->left = rb_first(&root->rb); |
| 425 | |
Jens Axboe | 0871714 | 2008-01-28 11:38:15 +0100 | [diff] [blame] | 426 | if (root->left) |
| 427 | return rb_entry(root->left, struct cfq_queue, rb_node); |
| 428 | |
| 429 | return NULL; |
Jens Axboe | cc09e29 | 2007-04-26 12:53:50 +0200 | [diff] [blame] | 430 | } |
| 431 | |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 432 | static void rb_erase_init(struct rb_node *n, struct rb_root *root) |
| 433 | { |
| 434 | rb_erase(n, root); |
| 435 | RB_CLEAR_NODE(n); |
| 436 | } |
| 437 | |
Jens Axboe | cc09e29 | 2007-04-26 12:53:50 +0200 | [diff] [blame] | 438 | static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root) |
| 439 | { |
| 440 | if (root->left == n) |
| 441 | root->left = NULL; |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 442 | rb_erase_init(n, &root->rb); |
Jens Axboe | cc09e29 | 2007-04-26 12:53:50 +0200 | [diff] [blame] | 443 | } |
| 444 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 445 | /* |
| 446 | * would be nice to take fifo expire time into account as well |
| 447 | */ |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 448 | static struct request * |
| 449 | cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
| 450 | struct request *last) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 451 | { |
Jens Axboe | 21183b0 | 2006-07-13 12:33:14 +0200 | [diff] [blame] | 452 | struct rb_node *rbnext = rb_next(&last->rb_node); |
| 453 | struct rb_node *rbprev = rb_prev(&last->rb_node); |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 454 | struct request *next = NULL, *prev = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 455 | |
Jens Axboe | 21183b0 | 2006-07-13 12:33:14 +0200 | [diff] [blame] | 456 | BUG_ON(RB_EMPTY_NODE(&last->rb_node)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 457 | |
| 458 | if (rbprev) |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 459 | prev = rb_entry_rq(rbprev); |
Jens Axboe | 21183b0 | 2006-07-13 12:33:14 +0200 | [diff] [blame] | 460 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 461 | if (rbnext) |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 462 | next = rb_entry_rq(rbnext); |
Jens Axboe | 21183b0 | 2006-07-13 12:33:14 +0200 | [diff] [blame] | 463 | else { |
| 464 | rbnext = rb_first(&cfqq->sort_list); |
| 465 | if (rbnext && rbnext != &last->rb_node) |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 466 | next = rb_entry_rq(rbnext); |
Jens Axboe | 21183b0 | 2006-07-13 12:33:14 +0200 | [diff] [blame] | 467 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 468 | |
Jens Axboe | 21183b0 | 2006-07-13 12:33:14 +0200 | [diff] [blame] | 469 | return cfq_choose_req(cfqd, next, prev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 470 | } |
| 471 | |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 472 | static unsigned long cfq_slice_offset(struct cfq_data *cfqd, |
| 473 | struct cfq_queue *cfqq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 474 | { |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 475 | /* |
| 476 | * just an approximation, should be ok. |
| 477 | */ |
Jens Axboe | 67e6b49 | 2007-04-20 14:18:00 +0200 | [diff] [blame] | 478 | return (cfqd->busy_queues - 1) * (cfq_prio_slice(cfqd, 1, 0) - |
| 479 | cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio)); |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 480 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 481 | |
Jens Axboe | 498d3aa2 | 2007-04-26 12:54:48 +0200 | [diff] [blame] | 482 | /* |
| 483 | * The cfqd->service_tree holds all pending cfq_queue's that have |
| 484 | * requests waiting to be processed. It is sorted in the order that |
| 485 | * we will service the queues. |
| 486 | */ |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 487 | static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
| 488 | int add_front) |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 489 | { |
Jens Axboe | 0871714 | 2008-01-28 11:38:15 +0100 | [diff] [blame] | 490 | struct rb_node **p, *parent; |
| 491 | struct cfq_queue *__cfqq; |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 492 | unsigned long rb_key; |
Jens Axboe | 498d3aa2 | 2007-04-26 12:54:48 +0200 | [diff] [blame] | 493 | int left; |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 494 | |
Jens Axboe | 0871714 | 2008-01-28 11:38:15 +0100 | [diff] [blame] | 495 | if (cfq_class_idle(cfqq)) { |
| 496 | rb_key = CFQ_IDLE_DELAY; |
| 497 | parent = rb_last(&cfqd->service_tree.rb); |
| 498 | if (parent && parent != &cfqq->rb_node) { |
| 499 | __cfqq = rb_entry(parent, struct cfq_queue, rb_node); |
| 500 | rb_key += __cfqq->rb_key; |
| 501 | } else |
| 502 | rb_key += jiffies; |
| 503 | } else if (!add_front) { |
Jens Axboe | edd75ff | 2007-04-19 12:03:34 +0200 | [diff] [blame] | 504 | rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies; |
| 505 | rb_key += cfqq->slice_resid; |
| 506 | cfqq->slice_resid = 0; |
| 507 | } else |
| 508 | rb_key = 0; |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 509 | |
| 510 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) { |
Jens Axboe | 99f9628 | 2007-02-05 11:56:25 +0100 | [diff] [blame] | 511 | /* |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 512 | * same position, nothing more to do |
Jens Axboe | 99f9628 | 2007-02-05 11:56:25 +0100 | [diff] [blame] | 513 | */ |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 514 | if (rb_key == cfqq->rb_key) |
| 515 | return; |
Jens Axboe | 53b03744 | 2006-07-28 09:48:51 +0200 | [diff] [blame] | 516 | |
Jens Axboe | cc09e29 | 2007-04-26 12:53:50 +0200 | [diff] [blame] | 517 | cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 518 | } |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 519 | |
Jens Axboe | 498d3aa2 | 2007-04-26 12:54:48 +0200 | [diff] [blame] | 520 | left = 1; |
Jens Axboe | 0871714 | 2008-01-28 11:38:15 +0100 | [diff] [blame] | 521 | parent = NULL; |
| 522 | p = &cfqd->service_tree.rb.rb_node; |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 523 | while (*p) { |
Jens Axboe | 67060e3 | 2007-04-18 20:13:32 +0200 | [diff] [blame] | 524 | struct rb_node **n; |
Jens Axboe | cc09e29 | 2007-04-26 12:53:50 +0200 | [diff] [blame] | 525 | |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 526 | parent = *p; |
| 527 | __cfqq = rb_entry(parent, struct cfq_queue, rb_node); |
| 528 | |
Jens Axboe | 0c534e0 | 2007-04-18 20:01:57 +0200 | [diff] [blame] | 529 | /* |
| 530 | * sort RT queues first, we always want to give |
Jens Axboe | 67060e3 | 2007-04-18 20:13:32 +0200 | [diff] [blame] | 531 | * preference to them. IDLE queues goes to the back. |
| 532 | * after that, sort on the next service time. |
Jens Axboe | 0c534e0 | 2007-04-18 20:01:57 +0200 | [diff] [blame] | 533 | */ |
| 534 | if (cfq_class_rt(cfqq) > cfq_class_rt(__cfqq)) |
Jens Axboe | 67060e3 | 2007-04-18 20:13:32 +0200 | [diff] [blame] | 535 | n = &(*p)->rb_left; |
Jens Axboe | 0c534e0 | 2007-04-18 20:01:57 +0200 | [diff] [blame] | 536 | else if (cfq_class_rt(cfqq) < cfq_class_rt(__cfqq)) |
Jens Axboe | 67060e3 | 2007-04-18 20:13:32 +0200 | [diff] [blame] | 537 | n = &(*p)->rb_right; |
| 538 | else if (cfq_class_idle(cfqq) < cfq_class_idle(__cfqq)) |
| 539 | n = &(*p)->rb_left; |
| 540 | else if (cfq_class_idle(cfqq) > cfq_class_idle(__cfqq)) |
| 541 | n = &(*p)->rb_right; |
Jens Axboe | 0c534e0 | 2007-04-18 20:01:57 +0200 | [diff] [blame] | 542 | else if (rb_key < __cfqq->rb_key) |
Jens Axboe | 67060e3 | 2007-04-18 20:13:32 +0200 | [diff] [blame] | 543 | n = &(*p)->rb_left; |
| 544 | else |
| 545 | n = &(*p)->rb_right; |
| 546 | |
| 547 | if (n == &(*p)->rb_right) |
Jens Axboe | cc09e29 | 2007-04-26 12:53:50 +0200 | [diff] [blame] | 548 | left = 0; |
Jens Axboe | 67060e3 | 2007-04-18 20:13:32 +0200 | [diff] [blame] | 549 | |
| 550 | p = n; |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 551 | } |
| 552 | |
Jens Axboe | cc09e29 | 2007-04-26 12:53:50 +0200 | [diff] [blame] | 553 | if (left) |
| 554 | cfqd->service_tree.left = &cfqq->rb_node; |
| 555 | |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 556 | cfqq->rb_key = rb_key; |
| 557 | rb_link_node(&cfqq->rb_node, parent, p); |
Jens Axboe | cc09e29 | 2007-04-26 12:53:50 +0200 | [diff] [blame] | 558 | rb_insert_color(&cfqq->rb_node, &cfqd->service_tree.rb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 559 | } |
| 560 | |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 561 | static struct cfq_queue * |
Jens Axboe | f2d1f0a | 2009-04-23 12:19:38 +0200 | [diff] [blame] | 562 | cfq_prio_tree_lookup(struct cfq_data *cfqd, struct rb_root *root, |
| 563 | sector_t sector, struct rb_node **ret_parent, |
| 564 | struct rb_node ***rb_link) |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 565 | { |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 566 | struct rb_node **p, *parent; |
| 567 | struct cfq_queue *cfqq = NULL; |
| 568 | |
| 569 | parent = NULL; |
| 570 | p = &root->rb_node; |
| 571 | while (*p) { |
| 572 | struct rb_node **n; |
| 573 | |
| 574 | parent = *p; |
| 575 | cfqq = rb_entry(parent, struct cfq_queue, p_node); |
| 576 | |
| 577 | /* |
| 578 | * Sort strictly based on sector. Smallest to the left, |
| 579 | * largest to the right. |
| 580 | */ |
Tejun Heo | 2e46e8b | 2009-05-07 22:24:41 +0900 | [diff] [blame] | 581 | if (sector > blk_rq_pos(cfqq->next_rq)) |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 582 | n = &(*p)->rb_right; |
Tejun Heo | 2e46e8b | 2009-05-07 22:24:41 +0900 | [diff] [blame] | 583 | else if (sector < blk_rq_pos(cfqq->next_rq)) |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 584 | n = &(*p)->rb_left; |
| 585 | else |
| 586 | break; |
| 587 | p = n; |
Jens Axboe | 3ac6c9f | 2009-04-23 12:14:56 +0200 | [diff] [blame] | 588 | cfqq = NULL; |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 589 | } |
| 590 | |
| 591 | *ret_parent = parent; |
| 592 | if (rb_link) |
| 593 | *rb_link = p; |
Jens Axboe | 3ac6c9f | 2009-04-23 12:14:56 +0200 | [diff] [blame] | 594 | return cfqq; |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 595 | } |
| 596 | |
| 597 | static void cfq_prio_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
| 598 | { |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 599 | struct rb_node **p, *parent; |
| 600 | struct cfq_queue *__cfqq; |
| 601 | |
Jens Axboe | f2d1f0a | 2009-04-23 12:19:38 +0200 | [diff] [blame] | 602 | if (cfqq->p_root) { |
| 603 | rb_erase(&cfqq->p_node, cfqq->p_root); |
| 604 | cfqq->p_root = NULL; |
| 605 | } |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 606 | |
| 607 | if (cfq_class_idle(cfqq)) |
| 608 | return; |
| 609 | if (!cfqq->next_rq) |
| 610 | return; |
| 611 | |
Jens Axboe | f2d1f0a | 2009-04-23 12:19:38 +0200 | [diff] [blame] | 612 | cfqq->p_root = &cfqd->prio_trees[cfqq->org_ioprio]; |
Tejun Heo | 2e46e8b | 2009-05-07 22:24:41 +0900 | [diff] [blame] | 613 | __cfqq = cfq_prio_tree_lookup(cfqd, cfqq->p_root, |
| 614 | blk_rq_pos(cfqq->next_rq), &parent, &p); |
Jens Axboe | 3ac6c9f | 2009-04-23 12:14:56 +0200 | [diff] [blame] | 615 | if (!__cfqq) { |
| 616 | rb_link_node(&cfqq->p_node, parent, p); |
Jens Axboe | f2d1f0a | 2009-04-23 12:19:38 +0200 | [diff] [blame] | 617 | rb_insert_color(&cfqq->p_node, cfqq->p_root); |
| 618 | } else |
| 619 | cfqq->p_root = NULL; |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 620 | } |
| 621 | |
Jens Axboe | 498d3aa2 | 2007-04-26 12:54:48 +0200 | [diff] [blame] | 622 | /* |
| 623 | * Update cfqq's position in the service tree. |
| 624 | */ |
Jens Axboe | edd75ff | 2007-04-19 12:03:34 +0200 | [diff] [blame] | 625 | static void cfq_resort_rr_list(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 626 | { |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 627 | /* |
| 628 | * Resorting requires the cfqq to be on the RR list already. |
| 629 | */ |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 630 | if (cfq_cfqq_on_rr(cfqq)) { |
Jens Axboe | edd75ff | 2007-04-19 12:03:34 +0200 | [diff] [blame] | 631 | cfq_service_tree_add(cfqd, cfqq, 0); |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 632 | cfq_prio_tree_add(cfqd, cfqq); |
| 633 | } |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 634 | } |
| 635 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 636 | /* |
| 637 | * 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] | 638 | * the pending list according to last request service |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 639 | */ |
Jens Axboe | febffd6 | 2008-01-28 13:19:43 +0100 | [diff] [blame] | 640 | static void cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 641 | { |
Jens Axboe | 7b67913 | 2008-05-30 12:23:07 +0200 | [diff] [blame] | 642 | cfq_log_cfqq(cfqd, cfqq, "add_to_rr"); |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 643 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
| 644 | cfq_mark_cfqq_on_rr(cfqq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 645 | cfqd->busy_queues++; |
Divyesh Shah | 3a9a3f6 | 2009-01-30 12:46:41 +0100 | [diff] [blame] | 646 | if (cfq_class_rt(cfqq)) |
| 647 | cfqd->busy_rt_queues++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 648 | |
Jens Axboe | edd75ff | 2007-04-19 12:03:34 +0200 | [diff] [blame] | 649 | cfq_resort_rr_list(cfqd, cfqq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 650 | } |
| 651 | |
Jens Axboe | 498d3aa2 | 2007-04-26 12:54:48 +0200 | [diff] [blame] | 652 | /* |
| 653 | * Called when the cfqq no longer has requests pending, remove it from |
| 654 | * the service tree. |
| 655 | */ |
Jens Axboe | febffd6 | 2008-01-28 13:19:43 +0100 | [diff] [blame] | 656 | static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 657 | { |
Jens Axboe | 7b67913 | 2008-05-30 12:23:07 +0200 | [diff] [blame] | 658 | cfq_log_cfqq(cfqd, cfqq, "del_from_rr"); |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 659 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
| 660 | cfq_clear_cfqq_on_rr(cfqq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 661 | |
Jens Axboe | cc09e29 | 2007-04-26 12:53:50 +0200 | [diff] [blame] | 662 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) |
| 663 | cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree); |
Jens Axboe | f2d1f0a | 2009-04-23 12:19:38 +0200 | [diff] [blame] | 664 | if (cfqq->p_root) { |
| 665 | rb_erase(&cfqq->p_node, cfqq->p_root); |
| 666 | cfqq->p_root = NULL; |
| 667 | } |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 668 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 669 | BUG_ON(!cfqd->busy_queues); |
| 670 | cfqd->busy_queues--; |
Divyesh Shah | 3a9a3f6 | 2009-01-30 12:46:41 +0100 | [diff] [blame] | 671 | if (cfq_class_rt(cfqq)) |
| 672 | cfqd->busy_rt_queues--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 673 | } |
| 674 | |
| 675 | /* |
| 676 | * rb tree support functions |
| 677 | */ |
Jens Axboe | febffd6 | 2008-01-28 13:19:43 +0100 | [diff] [blame] | 678 | static void cfq_del_rq_rb(struct request *rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 679 | { |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 680 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 681 | struct cfq_data *cfqd = cfqq->cfqd; |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 682 | const int sync = rq_is_sync(rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 683 | |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 684 | BUG_ON(!cfqq->queued[sync]); |
| 685 | cfqq->queued[sync]--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 686 | |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 687 | elv_rb_del(&cfqq->sort_list, rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 688 | |
Jens Axboe | dd67d05 | 2006-06-21 09:36:18 +0200 | [diff] [blame] | 689 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 690 | cfq_del_cfqq_rr(cfqd, cfqq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 691 | } |
| 692 | |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 693 | static void cfq_add_rq_rb(struct request *rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 694 | { |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 695 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 696 | struct cfq_data *cfqd = cfqq->cfqd; |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 697 | struct request *__alias, *prev; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 698 | |
Jens Axboe | 5380a10 | 2006-07-13 12:37:56 +0200 | [diff] [blame] | 699 | cfqq->queued[rq_is_sync(rq)]++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 700 | |
| 701 | /* |
| 702 | * looks a little odd, but the first insert might return an alias. |
| 703 | * if that happens, put the alias on the dispatch list |
| 704 | */ |
Jens Axboe | 21183b0 | 2006-07-13 12:33:14 +0200 | [diff] [blame] | 705 | while ((__alias = elv_rb_add(&cfqq->sort_list, rq)) != NULL) |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 706 | cfq_dispatch_insert(cfqd->queue, __alias); |
Jens Axboe | 5fccbf6 | 2006-10-31 14:21:55 +0100 | [diff] [blame] | 707 | |
| 708 | if (!cfq_cfqq_on_rr(cfqq)) |
| 709 | cfq_add_cfqq_rr(cfqd, cfqq); |
Jens Axboe | 5044eed | 2007-04-25 11:53:48 +0200 | [diff] [blame] | 710 | |
| 711 | /* |
| 712 | * check if this request is a better next-serve candidate |
| 713 | */ |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 714 | prev = cfqq->next_rq; |
Jens Axboe | 5044eed | 2007-04-25 11:53:48 +0200 | [diff] [blame] | 715 | cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq); |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 716 | |
| 717 | /* |
| 718 | * adjust priority tree position, if ->next_rq changes |
| 719 | */ |
| 720 | if (prev != cfqq->next_rq) |
| 721 | cfq_prio_tree_add(cfqd, cfqq); |
| 722 | |
Jens Axboe | 5044eed | 2007-04-25 11:53:48 +0200 | [diff] [blame] | 723 | BUG_ON(!cfqq->next_rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 724 | } |
| 725 | |
Jens Axboe | febffd6 | 2008-01-28 13:19:43 +0100 | [diff] [blame] | 726 | static void cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 727 | { |
Jens Axboe | 5380a10 | 2006-07-13 12:37:56 +0200 | [diff] [blame] | 728 | elv_rb_del(&cfqq->sort_list, rq); |
| 729 | cfqq->queued[rq_is_sync(rq)]--; |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 730 | cfq_add_rq_rb(rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 731 | } |
| 732 | |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 733 | static struct request * |
| 734 | cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 735 | { |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 736 | struct task_struct *tsk = current; |
Vasily Tarasov | 91fac31 | 2007-04-25 12:29:51 +0200 | [diff] [blame] | 737 | struct cfq_io_context *cic; |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 738 | struct cfq_queue *cfqq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 739 | |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 740 | cic = cfq_cic_lookup(cfqd, tsk->io_context); |
Vasily Tarasov | 91fac31 | 2007-04-25 12:29:51 +0200 | [diff] [blame] | 741 | if (!cic) |
| 742 | return NULL; |
| 743 | |
| 744 | cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 745 | if (cfqq) { |
| 746 | sector_t sector = bio->bi_sector + bio_sectors(bio); |
| 747 | |
Jens Axboe | 21183b0 | 2006-07-13 12:33:14 +0200 | [diff] [blame] | 748 | return elv_rb_find(&cfqq->sort_list, sector); |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 749 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 750 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 751 | return NULL; |
| 752 | } |
| 753 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 754 | static void cfq_activate_request(struct request_queue *q, struct request *rq) |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 755 | { |
| 756 | struct cfq_data *cfqd = q->elevator->elevator_data; |
| 757 | |
| 758 | cfqd->rq_in_driver++; |
Jens Axboe | 7b67913 | 2008-05-30 12:23:07 +0200 | [diff] [blame] | 759 | cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "activate rq, drv=%d", |
| 760 | cfqd->rq_in_driver); |
Jens Axboe | 25776e3 | 2006-06-01 10:12:26 +0200 | [diff] [blame] | 761 | |
Tejun Heo | 5b93629 | 2009-05-07 22:24:38 +0900 | [diff] [blame] | 762 | cfqd->last_position = blk_rq_pos(rq) + blk_rq_sectors(rq); |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 763 | } |
| 764 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 765 | static void cfq_deactivate_request(struct request_queue *q, struct request *rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 766 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 767 | struct cfq_data *cfqd = q->elevator->elevator_data; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 768 | |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 769 | WARN_ON(!cfqd->rq_in_driver); |
| 770 | cfqd->rq_in_driver--; |
Jens Axboe | 7b67913 | 2008-05-30 12:23:07 +0200 | [diff] [blame] | 771 | cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "deactivate rq, drv=%d", |
| 772 | cfqd->rq_in_driver); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 773 | } |
| 774 | |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 775 | static void cfq_remove_request(struct request *rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 776 | { |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 777 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
Jens Axboe | 21183b0 | 2006-07-13 12:33:14 +0200 | [diff] [blame] | 778 | |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 779 | if (cfqq->next_rq == rq) |
| 780 | cfqq->next_rq = cfq_find_next_rq(cfqq->cfqd, cfqq, rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 781 | |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 782 | list_del_init(&rq->queuelist); |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 783 | cfq_del_rq_rb(rq); |
Jens Axboe | 374f84a | 2006-07-23 01:42:19 +0200 | [diff] [blame] | 784 | |
Aaron Carroll | 45333d5 | 2008-08-26 15:52:36 +0200 | [diff] [blame] | 785 | cfqq->cfqd->rq_queued--; |
Jens Axboe | 374f84a | 2006-07-23 01:42:19 +0200 | [diff] [blame] | 786 | if (rq_is_meta(rq)) { |
| 787 | WARN_ON(!cfqq->meta_pending); |
| 788 | cfqq->meta_pending--; |
| 789 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 790 | } |
| 791 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 792 | static int cfq_merge(struct request_queue *q, struct request **req, |
| 793 | struct bio *bio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 794 | { |
| 795 | struct cfq_data *cfqd = q->elevator->elevator_data; |
| 796 | struct request *__rq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 797 | |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 798 | __rq = cfq_find_rq_fmerge(cfqd, bio); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 799 | if (__rq && elv_rq_merge_ok(__rq, bio)) { |
Jens Axboe | 9817064 | 2006-07-28 09:23:08 +0200 | [diff] [blame] | 800 | *req = __rq; |
| 801 | return ELEVATOR_FRONT_MERGE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 802 | } |
| 803 | |
| 804 | return ELEVATOR_NO_MERGE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 805 | } |
| 806 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 807 | static void cfq_merged_request(struct request_queue *q, struct request *req, |
Jens Axboe | 21183b0 | 2006-07-13 12:33:14 +0200 | [diff] [blame] | 808 | int type) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 809 | { |
Jens Axboe | 21183b0 | 2006-07-13 12:33:14 +0200 | [diff] [blame] | 810 | if (type == ELEVATOR_FRONT_MERGE) { |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 811 | struct cfq_queue *cfqq = RQ_CFQQ(req); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 812 | |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 813 | cfq_reposition_rq_rb(cfqq, req); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 814 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 815 | } |
| 816 | |
| 817 | static void |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 818 | cfq_merged_requests(struct request_queue *q, struct request *rq, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 819 | struct request *next) |
| 820 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 821 | /* |
| 822 | * reposition in fifo if next is older than rq |
| 823 | */ |
| 824 | if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && |
| 825 | time_before(next->start_time, rq->start_time)) |
| 826 | list_move(&rq->queuelist, &next->queuelist); |
| 827 | |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 828 | cfq_remove_request(next); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 829 | } |
| 830 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 831 | static int cfq_allow_merge(struct request_queue *q, struct request *rq, |
Jens Axboe | da77526 | 2006-12-20 11:04:12 +0100 | [diff] [blame] | 832 | struct bio *bio) |
| 833 | { |
| 834 | struct cfq_data *cfqd = q->elevator->elevator_data; |
Vasily Tarasov | 91fac31 | 2007-04-25 12:29:51 +0200 | [diff] [blame] | 835 | struct cfq_io_context *cic; |
Jens Axboe | da77526 | 2006-12-20 11:04:12 +0100 | [diff] [blame] | 836 | struct cfq_queue *cfqq; |
Jens Axboe | da77526 | 2006-12-20 11:04:12 +0100 | [diff] [blame] | 837 | |
| 838 | /* |
Jens Axboe | ec8acb6 | 2007-01-02 18:32:11 +0100 | [diff] [blame] | 839 | * Disallow merge of a sync bio into an async request. |
Jens Axboe | da77526 | 2006-12-20 11:04:12 +0100 | [diff] [blame] | 840 | */ |
Vasily Tarasov | 91fac31 | 2007-04-25 12:29:51 +0200 | [diff] [blame] | 841 | if (cfq_bio_sync(bio) && !rq_is_sync(rq)) |
Jens Axboe | da77526 | 2006-12-20 11:04:12 +0100 | [diff] [blame] | 842 | return 0; |
| 843 | |
| 844 | /* |
Jens Axboe | 719d340 | 2006-12-22 09:38:53 +0100 | [diff] [blame] | 845 | * Lookup the cfqq that this bio will be queued with. Allow |
| 846 | * merge only if rq is queued there. |
Jens Axboe | da77526 | 2006-12-20 11:04:12 +0100 | [diff] [blame] | 847 | */ |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 848 | cic = cfq_cic_lookup(cfqd, current->io_context); |
Vasily Tarasov | 91fac31 | 2007-04-25 12:29:51 +0200 | [diff] [blame] | 849 | if (!cic) |
| 850 | return 0; |
Jens Axboe | 719d340 | 2006-12-22 09:38:53 +0100 | [diff] [blame] | 851 | |
Vasily Tarasov | 91fac31 | 2007-04-25 12:29:51 +0200 | [diff] [blame] | 852 | cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); |
Jens Axboe | 719d340 | 2006-12-22 09:38:53 +0100 | [diff] [blame] | 853 | if (cfqq == RQ_CFQQ(rq)) |
| 854 | return 1; |
Jens Axboe | da77526 | 2006-12-20 11:04:12 +0100 | [diff] [blame] | 855 | |
Jens Axboe | ec8acb6 | 2007-01-02 18:32:11 +0100 | [diff] [blame] | 856 | return 0; |
Jens Axboe | da77526 | 2006-12-20 11:04:12 +0100 | [diff] [blame] | 857 | } |
| 858 | |
Jens Axboe | febffd6 | 2008-01-28 13:19:43 +0100 | [diff] [blame] | 859 | static void __cfq_set_active_queue(struct cfq_data *cfqd, |
| 860 | struct cfq_queue *cfqq) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 861 | { |
| 862 | if (cfqq) { |
Jens Axboe | 7b67913 | 2008-05-30 12:23:07 +0200 | [diff] [blame] | 863 | cfq_log_cfqq(cfqd, cfqq, "set_active"); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 864 | cfqq->slice_end = 0; |
Jens Axboe | 2f5cb73 | 2009-04-07 08:51:19 +0200 | [diff] [blame] | 865 | cfqq->slice_dispatch = 0; |
| 866 | |
Jens Axboe | 2f5cb73 | 2009-04-07 08:51:19 +0200 | [diff] [blame] | 867 | cfq_clear_cfqq_wait_request(cfqq); |
Jens Axboe | b029195 | 2009-04-07 11:38:31 +0200 | [diff] [blame] | 868 | cfq_clear_cfqq_must_dispatch(cfqq); |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 869 | cfq_clear_cfqq_must_alloc_slice(cfqq); |
| 870 | cfq_clear_cfqq_fifo_expire(cfqq); |
Jens Axboe | 44f7c16 | 2007-01-19 11:51:58 +1100 | [diff] [blame] | 871 | cfq_mark_cfqq_slice_new(cfqq); |
Jens Axboe | 2f5cb73 | 2009-04-07 08:51:19 +0200 | [diff] [blame] | 872 | |
| 873 | del_timer(&cfqd->idle_slice_timer); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 874 | } |
| 875 | |
| 876 | cfqd->active_queue = cfqq; |
| 877 | } |
| 878 | |
| 879 | /* |
Jens Axboe | 7b14e3b | 2006-02-28 09:35:11 +0100 | [diff] [blame] | 880 | * current cfqq expired its slice (or was too idle), select new one |
| 881 | */ |
| 882 | static void |
| 883 | __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
Jens Axboe | 6084cdd | 2007-04-23 08:25:00 +0200 | [diff] [blame] | 884 | int timed_out) |
Jens Axboe | 7b14e3b | 2006-02-28 09:35:11 +0100 | [diff] [blame] | 885 | { |
Jens Axboe | 7b67913 | 2008-05-30 12:23:07 +0200 | [diff] [blame] | 886 | cfq_log_cfqq(cfqd, cfqq, "slice expired t=%d", timed_out); |
| 887 | |
Jens Axboe | 7b14e3b | 2006-02-28 09:35:11 +0100 | [diff] [blame] | 888 | if (cfq_cfqq_wait_request(cfqq)) |
| 889 | del_timer(&cfqd->idle_slice_timer); |
| 890 | |
Jens Axboe | 7b14e3b | 2006-02-28 09:35:11 +0100 | [diff] [blame] | 891 | cfq_clear_cfqq_wait_request(cfqq); |
| 892 | |
| 893 | /* |
Jens Axboe | 6084cdd | 2007-04-23 08:25:00 +0200 | [diff] [blame] | 894 | * store what was left of this slice, if the queue idled/timed out |
Jens Axboe | 7b14e3b | 2006-02-28 09:35:11 +0100 | [diff] [blame] | 895 | */ |
Jens Axboe | 7b67913 | 2008-05-30 12:23:07 +0200 | [diff] [blame] | 896 | if (timed_out && !cfq_cfqq_slice_new(cfqq)) { |
Jens Axboe | c5b680f | 2007-01-19 11:56:49 +1100 | [diff] [blame] | 897 | cfqq->slice_resid = cfqq->slice_end - jiffies; |
Jens Axboe | 7b67913 | 2008-05-30 12:23:07 +0200 | [diff] [blame] | 898 | cfq_log_cfqq(cfqd, cfqq, "resid=%ld", cfqq->slice_resid); |
| 899 | } |
Jens Axboe | 7b14e3b | 2006-02-28 09:35:11 +0100 | [diff] [blame] | 900 | |
Jens Axboe | edd75ff | 2007-04-19 12:03:34 +0200 | [diff] [blame] | 901 | cfq_resort_rr_list(cfqd, cfqq); |
Jens Axboe | 7b14e3b | 2006-02-28 09:35:11 +0100 | [diff] [blame] | 902 | |
| 903 | if (cfqq == cfqd->active_queue) |
| 904 | cfqd->active_queue = NULL; |
| 905 | |
| 906 | if (cfqd->active_cic) { |
| 907 | put_io_context(cfqd->active_cic->ioc); |
| 908 | cfqd->active_cic = NULL; |
| 909 | } |
Jens Axboe | 7b14e3b | 2006-02-28 09:35:11 +0100 | [diff] [blame] | 910 | } |
| 911 | |
Jens Axboe | 6084cdd | 2007-04-23 08:25:00 +0200 | [diff] [blame] | 912 | static inline void cfq_slice_expired(struct cfq_data *cfqd, int timed_out) |
Jens Axboe | 7b14e3b | 2006-02-28 09:35:11 +0100 | [diff] [blame] | 913 | { |
| 914 | struct cfq_queue *cfqq = cfqd->active_queue; |
| 915 | |
| 916 | if (cfqq) |
Jens Axboe | 6084cdd | 2007-04-23 08:25:00 +0200 | [diff] [blame] | 917 | __cfq_slice_expired(cfqd, cfqq, timed_out); |
Jens Axboe | 7b14e3b | 2006-02-28 09:35:11 +0100 | [diff] [blame] | 918 | } |
| 919 | |
Jens Axboe | 498d3aa2 | 2007-04-26 12:54:48 +0200 | [diff] [blame] | 920 | /* |
| 921 | * Get next queue for service. Unless we have a queue preemption, |
| 922 | * we'll simply select the first cfqq in the service tree. |
| 923 | */ |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 924 | static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 925 | { |
Jens Axboe | edd75ff | 2007-04-19 12:03:34 +0200 | [diff] [blame] | 926 | if (RB_EMPTY_ROOT(&cfqd->service_tree.rb)) |
| 927 | return NULL; |
| 928 | |
Jens Axboe | 0871714 | 2008-01-28 11:38:15 +0100 | [diff] [blame] | 929 | return cfq_rb_first(&cfqd->service_tree); |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 930 | } |
| 931 | |
Jens Axboe | 498d3aa2 | 2007-04-26 12:54:48 +0200 | [diff] [blame] | 932 | /* |
| 933 | * Get and set a new active queue for service. |
| 934 | */ |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 935 | static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd, |
| 936 | struct cfq_queue *cfqq) |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 937 | { |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 938 | if (!cfqq) { |
| 939 | cfqq = cfq_get_next_queue(cfqd); |
| 940 | if (cfqq) |
| 941 | cfq_clear_cfqq_coop(cfqq); |
| 942 | } |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 943 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 944 | __cfq_set_active_queue(cfqd, cfqq); |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 945 | return cfqq; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 946 | } |
| 947 | |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 948 | static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd, |
| 949 | struct request *rq) |
| 950 | { |
Tejun Heo | 83096eb | 2009-05-07 22:24:39 +0900 | [diff] [blame] | 951 | if (blk_rq_pos(rq) >= cfqd->last_position) |
| 952 | return blk_rq_pos(rq) - cfqd->last_position; |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 953 | else |
Tejun Heo | 83096eb | 2009-05-07 22:24:39 +0900 | [diff] [blame] | 954 | return cfqd->last_position - blk_rq_pos(rq); |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 955 | } |
| 956 | |
Jeff Moyer | 04dc6e7 | 2009-04-21 07:31:56 +0200 | [diff] [blame] | 957 | #define CIC_SEEK_THR 8 * 1024 |
| 958 | #define CIC_SEEKY(cic) ((cic)->seek_mean > CIC_SEEK_THR) |
| 959 | |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 960 | static inline int cfq_rq_close(struct cfq_data *cfqd, struct request *rq) |
| 961 | { |
| 962 | struct cfq_io_context *cic = cfqd->active_cic; |
Jeff Moyer | 04dc6e7 | 2009-04-21 07:31:56 +0200 | [diff] [blame] | 963 | sector_t sdist = cic->seek_mean; |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 964 | |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 965 | if (!sample_valid(cic->seek_samples)) |
Jeff Moyer | 04dc6e7 | 2009-04-21 07:31:56 +0200 | [diff] [blame] | 966 | sdist = CIC_SEEK_THR; |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 967 | |
Jeff Moyer | 04dc6e7 | 2009-04-21 07:31:56 +0200 | [diff] [blame] | 968 | return cfq_dist_from_last(cfqd, rq) <= sdist; |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 969 | } |
| 970 | |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 971 | static struct cfq_queue *cfqq_close(struct cfq_data *cfqd, |
| 972 | struct cfq_queue *cur_cfqq) |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 973 | { |
Jens Axboe | f2d1f0a | 2009-04-23 12:19:38 +0200 | [diff] [blame] | 974 | struct rb_root *root = &cfqd->prio_trees[cur_cfqq->org_ioprio]; |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 975 | struct rb_node *parent, *node; |
| 976 | struct cfq_queue *__cfqq; |
| 977 | sector_t sector = cfqd->last_position; |
| 978 | |
| 979 | if (RB_EMPTY_ROOT(root)) |
| 980 | return NULL; |
| 981 | |
| 982 | /* |
| 983 | * First, if we find a request starting at the end of the last |
| 984 | * request, choose it. |
| 985 | */ |
Jens Axboe | f2d1f0a | 2009-04-23 12:19:38 +0200 | [diff] [blame] | 986 | __cfqq = cfq_prio_tree_lookup(cfqd, root, sector, &parent, NULL); |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 987 | if (__cfqq) |
| 988 | return __cfqq; |
| 989 | |
| 990 | /* |
| 991 | * If the exact sector wasn't found, the parent of the NULL leaf |
| 992 | * will contain the closest sector. |
| 993 | */ |
| 994 | __cfqq = rb_entry(parent, struct cfq_queue, p_node); |
| 995 | if (cfq_rq_close(cfqd, __cfqq->next_rq)) |
| 996 | return __cfqq; |
| 997 | |
Tejun Heo | 2e46e8b | 2009-05-07 22:24:41 +0900 | [diff] [blame] | 998 | if (blk_rq_pos(__cfqq->next_rq) < sector) |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 999 | node = rb_next(&__cfqq->p_node); |
| 1000 | else |
| 1001 | node = rb_prev(&__cfqq->p_node); |
| 1002 | if (!node) |
| 1003 | return NULL; |
| 1004 | |
| 1005 | __cfqq = rb_entry(node, struct cfq_queue, p_node); |
| 1006 | if (cfq_rq_close(cfqd, __cfqq->next_rq)) |
| 1007 | return __cfqq; |
| 1008 | |
| 1009 | return NULL; |
| 1010 | } |
| 1011 | |
| 1012 | /* |
| 1013 | * cfqd - obvious |
| 1014 | * cur_cfqq - passed in so that we don't decide that the current queue is |
| 1015 | * closely cooperating with itself. |
| 1016 | * |
| 1017 | * So, basically we're assuming that that cur_cfqq has dispatched at least |
| 1018 | * one request, and that cfqd->last_position reflects a position on the disk |
| 1019 | * associated with the I/O issued by cur_cfqq. I'm not sure this is a valid |
| 1020 | * assumption. |
| 1021 | */ |
| 1022 | static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd, |
| 1023 | struct cfq_queue *cur_cfqq, |
| 1024 | int probe) |
| 1025 | { |
| 1026 | struct cfq_queue *cfqq; |
| 1027 | |
| 1028 | /* |
| 1029 | * A valid cfq_io_context is necessary to compare requests against |
| 1030 | * the seek_mean of the current cfqq. |
| 1031 | */ |
| 1032 | if (!cfqd->active_cic) |
| 1033 | return NULL; |
| 1034 | |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 1035 | /* |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 1036 | * We should notice if some of the queues are cooperating, eg |
| 1037 | * working closely on the same area of the disk. In that case, |
| 1038 | * we can group them together and don't waste time idling. |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 1039 | */ |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 1040 | cfqq = cfqq_close(cfqd, cur_cfqq); |
| 1041 | if (!cfqq) |
| 1042 | return NULL; |
| 1043 | |
| 1044 | if (cfq_cfqq_coop(cfqq)) |
| 1045 | return NULL; |
| 1046 | |
| 1047 | if (!probe) |
| 1048 | cfq_mark_cfqq_coop(cfqq); |
| 1049 | return cfqq; |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 1050 | } |
| 1051 | |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 1052 | static void cfq_arm_slice_timer(struct cfq_data *cfqd) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1053 | { |
Jens Axboe | 1792669 | 2007-01-19 11:59:30 +1100 | [diff] [blame] | 1054 | struct cfq_queue *cfqq = cfqd->active_queue; |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 1055 | struct cfq_io_context *cic; |
Jens Axboe | 7b14e3b | 2006-02-28 09:35:11 +0100 | [diff] [blame] | 1056 | unsigned long sl; |
| 1057 | |
Jens Axboe | a68bbddba | 2008-09-24 13:03:33 +0200 | [diff] [blame] | 1058 | /* |
Jens Axboe | f7d7b7a | 2008-09-25 11:37:50 +0200 | [diff] [blame] | 1059 | * SSD device without seek penalty, disable idling. But only do so |
| 1060 | * for devices that support queuing, otherwise we still have a problem |
| 1061 | * with sync vs async workloads. |
Jens Axboe | a68bbddba | 2008-09-24 13:03:33 +0200 | [diff] [blame] | 1062 | */ |
Jens Axboe | f7d7b7a | 2008-09-25 11:37:50 +0200 | [diff] [blame] | 1063 | if (blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag) |
Jens Axboe | a68bbddba | 2008-09-24 13:03:33 +0200 | [diff] [blame] | 1064 | return; |
| 1065 | |
Jens Axboe | dd67d05 | 2006-06-21 09:36:18 +0200 | [diff] [blame] | 1066 | WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list)); |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 1067 | WARN_ON(cfq_cfqq_slice_new(cfqq)); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1068 | |
| 1069 | /* |
| 1070 | * idle is disabled, either manually or by past process history |
| 1071 | */ |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 1072 | if (!cfqd->cfq_slice_idle || !cfq_cfqq_idle_window(cfqq)) |
| 1073 | return; |
| 1074 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1075 | /* |
Jens Axboe | 7b67913 | 2008-05-30 12:23:07 +0200 | [diff] [blame] | 1076 | * still requests with the driver, don't idle |
| 1077 | */ |
| 1078 | if (cfqd->rq_in_driver) |
| 1079 | return; |
| 1080 | |
| 1081 | /* |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1082 | * task has exited, don't wait |
| 1083 | */ |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 1084 | cic = cfqd->active_cic; |
Nikanth Karthikesan | 66dac98 | 2007-11-27 12:47:04 +0100 | [diff] [blame] | 1085 | if (!cic || !atomic_read(&cic->ioc->nr_tasks)) |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 1086 | return; |
| 1087 | |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1088 | cfq_mark_cfqq_wait_request(cfqq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1089 | |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 1090 | /* |
| 1091 | * we don't want to idle for seeks, but we do want to allow |
| 1092 | * fair distribution of slice time for a process doing back-to-back |
| 1093 | * seeks. so allow a little bit of time for him to submit a new rq |
| 1094 | */ |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 1095 | sl = cfqd->cfq_slice_idle; |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 1096 | if (sample_valid(cic->seek_samples) && CIC_SEEKY(cic)) |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 1097 | sl = min(sl, msecs_to_jiffies(CFQ_MIN_TT)); |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 1098 | |
Jens Axboe | 7b14e3b | 2006-02-28 09:35:11 +0100 | [diff] [blame] | 1099 | mod_timer(&cfqd->idle_slice_timer, jiffies + sl); |
Jens Axboe | 9481ffd | 2009-04-15 12:14:13 +0200 | [diff] [blame] | 1100 | cfq_log_cfqq(cfqd, cfqq, "arm_idle: %lu", sl); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1101 | } |
| 1102 | |
Jens Axboe | 498d3aa2 | 2007-04-26 12:54:48 +0200 | [diff] [blame] | 1103 | /* |
| 1104 | * Move request from internal lists to the request queue dispatch list. |
| 1105 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 1106 | static void cfq_dispatch_insert(struct request_queue *q, struct request *rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1107 | { |
Jens Axboe | 3ed9a29 | 2007-04-23 08:33:33 +0200 | [diff] [blame] | 1108 | struct cfq_data *cfqd = q->elevator->elevator_data; |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 1109 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1110 | |
Jens Axboe | 7b67913 | 2008-05-30 12:23:07 +0200 | [diff] [blame] | 1111 | cfq_log_cfqq(cfqd, cfqq, "dispatch_insert"); |
| 1112 | |
Jens Axboe | 5380a10 | 2006-07-13 12:37:56 +0200 | [diff] [blame] | 1113 | cfq_remove_request(rq); |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 1114 | cfqq->dispatched++; |
Jens Axboe | 5380a10 | 2006-07-13 12:37:56 +0200 | [diff] [blame] | 1115 | elv_dispatch_sort(q, rq); |
Jens Axboe | 3ed9a29 | 2007-04-23 08:33:33 +0200 | [diff] [blame] | 1116 | |
| 1117 | if (cfq_cfqq_sync(cfqq)) |
| 1118 | cfqd->sync_flight++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1119 | } |
| 1120 | |
| 1121 | /* |
| 1122 | * return expired entry, or NULL to just start from scratch in rbtree |
| 1123 | */ |
Jens Axboe | febffd6 | 2008-01-28 13:19:43 +0100 | [diff] [blame] | 1124 | static struct request *cfq_check_fifo(struct cfq_queue *cfqq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1125 | { |
| 1126 | struct cfq_data *cfqd = cfqq->cfqd; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1127 | struct request *rq; |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 1128 | int fifo; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1129 | |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1130 | if (cfq_cfqq_fifo_expire(cfqq)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1131 | return NULL; |
Jens Axboe | cb88741 | 2007-01-19 12:01:16 +1100 | [diff] [blame] | 1132 | |
| 1133 | cfq_mark_cfqq_fifo_expire(cfqq); |
| 1134 | |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 1135 | if (list_empty(&cfqq->fifo)) |
| 1136 | return NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1137 | |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 1138 | fifo = cfq_cfqq_sync(cfqq); |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 1139 | rq = rq_entry_fifo(cfqq->fifo.next); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1140 | |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 1141 | if (time_before(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) |
Jens Axboe | 7b67913 | 2008-05-30 12:23:07 +0200 | [diff] [blame] | 1142 | rq = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1143 | |
Jens Axboe | 7b67913 | 2008-05-30 12:23:07 +0200 | [diff] [blame] | 1144 | cfq_log_cfqq(cfqd, cfqq, "fifo=%p", rq); |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 1145 | return rq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1146 | } |
| 1147 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1148 | static inline int |
| 1149 | cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
| 1150 | { |
| 1151 | const int base_rq = cfqd->cfq_slice_async_rq; |
| 1152 | |
| 1153 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); |
| 1154 | |
| 1155 | return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio)); |
| 1156 | } |
| 1157 | |
| 1158 | /* |
Jens Axboe | 498d3aa2 | 2007-04-26 12:54:48 +0200 | [diff] [blame] | 1159 | * Select a queue for service. If we have a current active queue, |
| 1160 | * check whether to continue servicing it, or retrieve and set a new one. |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1161 | */ |
Tejun Heo | 1b5ed5e1 | 2005-11-10 08:49:19 +0100 | [diff] [blame] | 1162 | static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1163 | { |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 1164 | struct cfq_queue *cfqq, *new_cfqq = NULL; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1165 | |
| 1166 | cfqq = cfqd->active_queue; |
| 1167 | if (!cfqq) |
| 1168 | goto new_queue; |
| 1169 | |
| 1170 | /* |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 1171 | * The active queue has run out of time, expire it and select new. |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1172 | */ |
Jens Axboe | b029195 | 2009-04-07 11:38:31 +0200 | [diff] [blame] | 1173 | if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq)) |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1174 | goto expire; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1175 | |
| 1176 | /* |
Divyesh Shah | 3a9a3f6 | 2009-01-30 12:46:41 +0100 | [diff] [blame] | 1177 | * If we have a RT cfqq waiting, then we pre-empt the current non-rt |
| 1178 | * cfqq. |
| 1179 | */ |
| 1180 | if (!cfq_class_rt(cfqq) && cfqd->busy_rt_queues) { |
| 1181 | /* |
| 1182 | * We simulate this as cfqq timed out so that it gets to bank |
| 1183 | * the remaining of its time slice. |
| 1184 | */ |
| 1185 | cfq_log_cfqq(cfqd, cfqq, "preempt"); |
| 1186 | cfq_slice_expired(cfqd, 1); |
| 1187 | goto new_queue; |
| 1188 | } |
| 1189 | |
| 1190 | /* |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 1191 | * The active queue has requests and isn't expired, allow it to |
| 1192 | * dispatch. |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1193 | */ |
Jens Axboe | dd67d05 | 2006-06-21 09:36:18 +0200 | [diff] [blame] | 1194 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1195 | goto keep_queue; |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 1196 | |
| 1197 | /* |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 1198 | * If another queue has a request waiting within our mean seek |
| 1199 | * distance, let it run. The expire code will check for close |
| 1200 | * cooperators and put the close queue at the front of the service |
| 1201 | * tree. |
| 1202 | */ |
| 1203 | new_cfqq = cfq_close_cooperator(cfqd, cfqq, 0); |
| 1204 | if (new_cfqq) |
| 1205 | goto expire; |
| 1206 | |
| 1207 | /* |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 1208 | * No requests pending. If the active queue still has requests in |
| 1209 | * flight or is idling for a new request, allow either of these |
| 1210 | * conditions to happen (or time out) before selecting a new queue. |
| 1211 | */ |
Jens Axboe | cc19747 | 2007-04-20 20:45:39 +0200 | [diff] [blame] | 1212 | if (timer_pending(&cfqd->idle_slice_timer) || |
| 1213 | (cfqq->dispatched && cfq_cfqq_idle_window(cfqq))) { |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 1214 | cfqq = NULL; |
| 1215 | goto keep_queue; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1216 | } |
| 1217 | |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1218 | expire: |
Jens Axboe | 6084cdd | 2007-04-23 08:25:00 +0200 | [diff] [blame] | 1219 | cfq_slice_expired(cfqd, 0); |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1220 | new_queue: |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 1221 | cfqq = cfq_set_active_queue(cfqd, new_cfqq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1222 | keep_queue: |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1223 | return cfqq; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1224 | } |
| 1225 | |
Jens Axboe | febffd6 | 2008-01-28 13:19:43 +0100 | [diff] [blame] | 1226 | static int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq) |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 1227 | { |
| 1228 | int dispatched = 0; |
| 1229 | |
| 1230 | while (cfqq->next_rq) { |
| 1231 | cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq); |
| 1232 | dispatched++; |
| 1233 | } |
| 1234 | |
| 1235 | BUG_ON(!list_empty(&cfqq->fifo)); |
| 1236 | return dispatched; |
| 1237 | } |
| 1238 | |
Jens Axboe | 498d3aa2 | 2007-04-26 12:54:48 +0200 | [diff] [blame] | 1239 | /* |
| 1240 | * Drain our current requests. Used for barriers and when switching |
| 1241 | * io schedulers on-the-fly. |
| 1242 | */ |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 1243 | static int cfq_forced_dispatch(struct cfq_data *cfqd) |
Tejun Heo | 1b5ed5e1 | 2005-11-10 08:49:19 +0100 | [diff] [blame] | 1244 | { |
Jens Axboe | 0871714 | 2008-01-28 11:38:15 +0100 | [diff] [blame] | 1245 | struct cfq_queue *cfqq; |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 1246 | int dispatched = 0; |
Tejun Heo | 1b5ed5e1 | 2005-11-10 08:49:19 +0100 | [diff] [blame] | 1247 | |
Jens Axboe | 0871714 | 2008-01-28 11:38:15 +0100 | [diff] [blame] | 1248 | while ((cfqq = cfq_rb_first(&cfqd->service_tree)) != NULL) |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 1249 | dispatched += __cfq_forced_dispatch_cfqq(cfqq); |
Tejun Heo | 1b5ed5e1 | 2005-11-10 08:49:19 +0100 | [diff] [blame] | 1250 | |
Jens Axboe | 6084cdd | 2007-04-23 08:25:00 +0200 | [diff] [blame] | 1251 | cfq_slice_expired(cfqd, 0); |
Tejun Heo | 1b5ed5e1 | 2005-11-10 08:49:19 +0100 | [diff] [blame] | 1252 | |
| 1253 | BUG_ON(cfqd->busy_queues); |
| 1254 | |
Jeff Moyer | 6923715 | 2009-06-12 15:29:30 +0200 | [diff] [blame] | 1255 | cfq_log(cfqd, "forced_dispatch=%d", dispatched); |
Tejun Heo | 1b5ed5e1 | 2005-11-10 08:49:19 +0100 | [diff] [blame] | 1256 | return dispatched; |
| 1257 | } |
| 1258 | |
Jens Axboe | 2f5cb73 | 2009-04-07 08:51:19 +0200 | [diff] [blame] | 1259 | /* |
| 1260 | * Dispatch a request from cfqq, moving them to the request queue |
| 1261 | * dispatch list. |
| 1262 | */ |
| 1263 | static void cfq_dispatch_request(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
| 1264 | { |
| 1265 | struct request *rq; |
| 1266 | |
| 1267 | BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list)); |
| 1268 | |
| 1269 | /* |
| 1270 | * follow expired path, else get first next available |
| 1271 | */ |
| 1272 | rq = cfq_check_fifo(cfqq); |
| 1273 | if (!rq) |
| 1274 | rq = cfqq->next_rq; |
| 1275 | |
| 1276 | /* |
| 1277 | * insert request into driver dispatch list |
| 1278 | */ |
| 1279 | cfq_dispatch_insert(cfqd->queue, rq); |
| 1280 | |
| 1281 | if (!cfqd->active_cic) { |
| 1282 | struct cfq_io_context *cic = RQ_CIC(rq); |
| 1283 | |
Nikanth Karthikesan | d9c7d39 | 2009-06-10 12:57:06 -0700 | [diff] [blame] | 1284 | atomic_long_inc(&cic->ioc->refcount); |
Jens Axboe | 2f5cb73 | 2009-04-07 08:51:19 +0200 | [diff] [blame] | 1285 | cfqd->active_cic = cic; |
| 1286 | } |
| 1287 | } |
| 1288 | |
| 1289 | /* |
| 1290 | * Find the cfqq that we need to service and move a request from that to the |
| 1291 | * dispatch list |
| 1292 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 1293 | static int cfq_dispatch_requests(struct request_queue *q, int force) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1294 | { |
| 1295 | struct cfq_data *cfqd = q->elevator->elevator_data; |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 1296 | struct cfq_queue *cfqq; |
Jens Axboe | 2f5cb73 | 2009-04-07 08:51:19 +0200 | [diff] [blame] | 1297 | unsigned int max_dispatch; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1298 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1299 | if (!cfqd->busy_queues) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1300 | return 0; |
| 1301 | |
Tejun Heo | 1b5ed5e1 | 2005-11-10 08:49:19 +0100 | [diff] [blame] | 1302 | if (unlikely(force)) |
| 1303 | return cfq_forced_dispatch(cfqd); |
| 1304 | |
Jens Axboe | 2f5cb73 | 2009-04-07 08:51:19 +0200 | [diff] [blame] | 1305 | cfqq = cfq_select_queue(cfqd); |
| 1306 | if (!cfqq) |
| 1307 | return 0; |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 1308 | |
Jens Axboe | 2f5cb73 | 2009-04-07 08:51:19 +0200 | [diff] [blame] | 1309 | /* |
| 1310 | * If this is an async queue and we have sync IO in flight, let it wait |
| 1311 | */ |
| 1312 | if (cfqd->sync_flight && !cfq_cfqq_sync(cfqq)) |
| 1313 | return 0; |
| 1314 | |
| 1315 | max_dispatch = cfqd->cfq_quantum; |
| 1316 | if (cfq_class_idle(cfqq)) |
| 1317 | max_dispatch = 1; |
| 1318 | |
| 1319 | /* |
| 1320 | * Does this cfqq already have too much IO in flight? |
| 1321 | */ |
| 1322 | if (cfqq->dispatched >= max_dispatch) { |
| 1323 | /* |
| 1324 | * idle queue must always only have a single IO in flight |
| 1325 | */ |
Jens Axboe | 3ed9a29 | 2007-04-23 08:33:33 +0200 | [diff] [blame] | 1326 | if (cfq_class_idle(cfqq)) |
Jens Axboe | 2f5cb73 | 2009-04-07 08:51:19 +0200 | [diff] [blame] | 1327 | return 0; |
Jens Axboe | 3ed9a29 | 2007-04-23 08:33:33 +0200 | [diff] [blame] | 1328 | |
Jens Axboe | 2f5cb73 | 2009-04-07 08:51:19 +0200 | [diff] [blame] | 1329 | /* |
| 1330 | * We have other queues, don't allow more IO from this one |
| 1331 | */ |
| 1332 | if (cfqd->busy_queues > 1) |
| 1333 | return 0; |
Jens Axboe | 9ede209 | 2007-01-19 12:11:44 +1100 | [diff] [blame] | 1334 | |
Jens Axboe | 2f5cb73 | 2009-04-07 08:51:19 +0200 | [diff] [blame] | 1335 | /* |
| 1336 | * we are the only queue, allow up to 4 times of 'quantum' |
| 1337 | */ |
| 1338 | if (cfqq->dispatched >= 4 * max_dispatch) |
| 1339 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1340 | } |
| 1341 | |
Jens Axboe | 2f5cb73 | 2009-04-07 08:51:19 +0200 | [diff] [blame] | 1342 | /* |
| 1343 | * Dispatch a request from this cfqq |
| 1344 | */ |
| 1345 | cfq_dispatch_request(cfqd, cfqq); |
| 1346 | cfqq->slice_dispatch++; |
Jens Axboe | b029195 | 2009-04-07 11:38:31 +0200 | [diff] [blame] | 1347 | cfq_clear_cfqq_must_dispatch(cfqq); |
Jens Axboe | 2f5cb73 | 2009-04-07 08:51:19 +0200 | [diff] [blame] | 1348 | |
| 1349 | /* |
| 1350 | * expire an async queue immediately if it has used up its slice. idle |
| 1351 | * queue always expire after 1 dispatch round. |
| 1352 | */ |
| 1353 | if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) && |
| 1354 | cfqq->slice_dispatch >= cfq_prio_to_maxrq(cfqd, cfqq)) || |
| 1355 | cfq_class_idle(cfqq))) { |
| 1356 | cfqq->slice_end = jiffies + 1; |
| 1357 | cfq_slice_expired(cfqd, 0); |
| 1358 | } |
| 1359 | |
| 1360 | cfq_log(cfqd, "dispatched a request"); |
| 1361 | return 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1362 | } |
| 1363 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1364 | /* |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 1365 | * task holds one reference to the queue, dropped when task exits. each rq |
| 1366 | * 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] | 1367 | * |
| 1368 | * queue lock must be held here. |
| 1369 | */ |
| 1370 | static void cfq_put_queue(struct cfq_queue *cfqq) |
| 1371 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1372 | struct cfq_data *cfqd = cfqq->cfqd; |
| 1373 | |
| 1374 | BUG_ON(atomic_read(&cfqq->ref) <= 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1375 | |
| 1376 | if (!atomic_dec_and_test(&cfqq->ref)) |
| 1377 | return; |
| 1378 | |
Jens Axboe | 7b67913 | 2008-05-30 12:23:07 +0200 | [diff] [blame] | 1379 | cfq_log_cfqq(cfqd, cfqq, "put_queue"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1380 | BUG_ON(rb_first(&cfqq->sort_list)); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1381 | BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]); |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1382 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1383 | |
Jens Axboe | 28f95cbc | 2007-01-19 12:09:53 +1100 | [diff] [blame] | 1384 | if (unlikely(cfqd->active_queue == cfqq)) { |
Jens Axboe | 6084cdd | 2007-04-23 08:25:00 +0200 | [diff] [blame] | 1385 | __cfq_slice_expired(cfqd, cfqq, 0); |
Jens Axboe | 28f95cbc | 2007-01-19 12:09:53 +1100 | [diff] [blame] | 1386 | cfq_schedule_dispatch(cfqd); |
| 1387 | } |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1388 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1389 | kmem_cache_free(cfq_pool, cfqq); |
| 1390 | } |
| 1391 | |
Jens Axboe | d6de8be | 2008-05-28 14:46:59 +0200 | [diff] [blame] | 1392 | /* |
| 1393 | * Must always be called with the rcu_read_lock() held |
| 1394 | */ |
Jens Axboe | 07416d2 | 2008-05-07 09:17:12 +0200 | [diff] [blame] | 1395 | static void |
| 1396 | __call_for_each_cic(struct io_context *ioc, |
| 1397 | void (*func)(struct io_context *, struct cfq_io_context *)) |
| 1398 | { |
| 1399 | struct cfq_io_context *cic; |
| 1400 | struct hlist_node *n; |
| 1401 | |
| 1402 | hlist_for_each_entry_rcu(cic, n, &ioc->cic_list, cic_list) |
| 1403 | func(ioc, cic); |
| 1404 | } |
| 1405 | |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1406 | /* |
Fabio Checconi | 34e6bbf | 2008-04-02 14:31:02 +0200 | [diff] [blame] | 1407 | * Call func for each cic attached to this ioc. |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1408 | */ |
Fabio Checconi | 34e6bbf | 2008-04-02 14:31:02 +0200 | [diff] [blame] | 1409 | static void |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1410 | call_for_each_cic(struct io_context *ioc, |
| 1411 | void (*func)(struct io_context *, struct cfq_io_context *)) |
| 1412 | { |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1413 | rcu_read_lock(); |
Jens Axboe | 07416d2 | 2008-05-07 09:17:12 +0200 | [diff] [blame] | 1414 | __call_for_each_cic(ioc, func); |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1415 | rcu_read_unlock(); |
Fabio Checconi | 34e6bbf | 2008-04-02 14:31:02 +0200 | [diff] [blame] | 1416 | } |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1417 | |
Fabio Checconi | 34e6bbf | 2008-04-02 14:31:02 +0200 | [diff] [blame] | 1418 | static void cfq_cic_free_rcu(struct rcu_head *head) |
| 1419 | { |
| 1420 | struct cfq_io_context *cic; |
| 1421 | |
| 1422 | cic = container_of(head, struct cfq_io_context, rcu_head); |
| 1423 | |
| 1424 | kmem_cache_free(cfq_ioc_pool, cic); |
| 1425 | elv_ioc_count_dec(ioc_count); |
| 1426 | |
Jens Axboe | 9a11b4e | 2008-05-29 09:32:08 +0200 | [diff] [blame] | 1427 | if (ioc_gone) { |
| 1428 | /* |
| 1429 | * CFQ scheduler is exiting, grab exit lock and check |
| 1430 | * the pending io context count. If it hits zero, |
| 1431 | * complete ioc_gone and set it back to NULL |
| 1432 | */ |
| 1433 | spin_lock(&ioc_gone_lock); |
| 1434 | if (ioc_gone && !elv_ioc_count_read(ioc_count)) { |
| 1435 | complete(ioc_gone); |
| 1436 | ioc_gone = NULL; |
| 1437 | } |
| 1438 | spin_unlock(&ioc_gone_lock); |
| 1439 | } |
Fabio Checconi | 34e6bbf | 2008-04-02 14:31:02 +0200 | [diff] [blame] | 1440 | } |
| 1441 | |
| 1442 | static void cfq_cic_free(struct cfq_io_context *cic) |
| 1443 | { |
| 1444 | call_rcu(&cic->rcu_head, cfq_cic_free_rcu); |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1445 | } |
| 1446 | |
| 1447 | static void cic_free_func(struct io_context *ioc, struct cfq_io_context *cic) |
| 1448 | { |
| 1449 | unsigned long flags; |
| 1450 | |
| 1451 | BUG_ON(!cic->dead_key); |
| 1452 | |
| 1453 | spin_lock_irqsave(&ioc->lock, flags); |
| 1454 | radix_tree_delete(&ioc->radix_root, cic->dead_key); |
Jens Axboe | ffc4e75 | 2008-02-19 10:02:29 +0100 | [diff] [blame] | 1455 | hlist_del_rcu(&cic->cic_list); |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1456 | spin_unlock_irqrestore(&ioc->lock, flags); |
| 1457 | |
Fabio Checconi | 34e6bbf | 2008-04-02 14:31:02 +0200 | [diff] [blame] | 1458 | cfq_cic_free(cic); |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1459 | } |
| 1460 | |
Jens Axboe | d6de8be | 2008-05-28 14:46:59 +0200 | [diff] [blame] | 1461 | /* |
| 1462 | * Must be called with rcu_read_lock() held or preemption otherwise disabled. |
| 1463 | * Only two callers of this - ->dtor() which is called with the rcu_read_lock(), |
| 1464 | * and ->trim() which is called with the task lock held |
| 1465 | */ |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1466 | static void cfq_free_io_context(struct io_context *ioc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1467 | { |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1468 | /* |
Fabio Checconi | 34e6bbf | 2008-04-02 14:31:02 +0200 | [diff] [blame] | 1469 | * ioc->refcount is zero here, or we are called from elv_unregister(), |
| 1470 | * so no more cic's are allowed to be linked into this ioc. So it |
| 1471 | * should be ok to iterate over the known list, we will see all cic's |
| 1472 | * since no new ones are added. |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1473 | */ |
Jens Axboe | 07416d2 | 2008-05-07 09:17:12 +0200 | [diff] [blame] | 1474 | __call_for_each_cic(ioc, cic_free_func); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1475 | } |
| 1476 | |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 1477 | static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
| 1478 | { |
Jens Axboe | 28f95cbc | 2007-01-19 12:09:53 +1100 | [diff] [blame] | 1479 | if (unlikely(cfqq == cfqd->active_queue)) { |
Jens Axboe | 6084cdd | 2007-04-23 08:25:00 +0200 | [diff] [blame] | 1480 | __cfq_slice_expired(cfqd, cfqq, 0); |
Jens Axboe | 28f95cbc | 2007-01-19 12:09:53 +1100 | [diff] [blame] | 1481 | cfq_schedule_dispatch(cfqd); |
| 1482 | } |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 1483 | |
| 1484 | cfq_put_queue(cfqq); |
| 1485 | } |
| 1486 | |
| 1487 | static void __cfq_exit_single_io_context(struct cfq_data *cfqd, |
| 1488 | struct cfq_io_context *cic) |
| 1489 | { |
Fabio Checconi | 4faa3c8 | 2008-04-10 08:28:01 +0200 | [diff] [blame] | 1490 | struct io_context *ioc = cic->ioc; |
| 1491 | |
Jens Axboe | fc46379 | 2006-08-29 09:05:44 +0200 | [diff] [blame] | 1492 | list_del_init(&cic->queue_list); |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1493 | |
| 1494 | /* |
| 1495 | * Make sure key == NULL is seen for dead queues |
| 1496 | */ |
Jens Axboe | fc46379 | 2006-08-29 09:05:44 +0200 | [diff] [blame] | 1497 | smp_wmb(); |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1498 | cic->dead_key = (unsigned long) cic->key; |
Jens Axboe | fc46379 | 2006-08-29 09:05:44 +0200 | [diff] [blame] | 1499 | cic->key = NULL; |
| 1500 | |
Fabio Checconi | 4faa3c8 | 2008-04-10 08:28:01 +0200 | [diff] [blame] | 1501 | if (ioc->ioc_data == cic) |
| 1502 | rcu_assign_pointer(ioc->ioc_data, NULL); |
| 1503 | |
Jens Axboe | ff6657c | 2009-04-08 10:58:57 +0200 | [diff] [blame] | 1504 | if (cic->cfqq[BLK_RW_ASYNC]) { |
| 1505 | cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_ASYNC]); |
| 1506 | cic->cfqq[BLK_RW_ASYNC] = NULL; |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 1507 | } |
| 1508 | |
Jens Axboe | ff6657c | 2009-04-08 10:58:57 +0200 | [diff] [blame] | 1509 | if (cic->cfqq[BLK_RW_SYNC]) { |
| 1510 | cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_SYNC]); |
| 1511 | cic->cfqq[BLK_RW_SYNC] = NULL; |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 1512 | } |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 1513 | } |
| 1514 | |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1515 | static void cfq_exit_single_io_context(struct io_context *ioc, |
| 1516 | struct cfq_io_context *cic) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1517 | { |
Al Viro | 478a82b | 2006-03-18 13:25:24 -0500 | [diff] [blame] | 1518 | struct cfq_data *cfqd = cic->key; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1519 | |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 1520 | if (cfqd) { |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 1521 | struct request_queue *q = cfqd->queue; |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1522 | unsigned long flags; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1523 | |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1524 | spin_lock_irqsave(q->queue_lock, flags); |
Jens Axboe | 62c1fe9 | 2008-12-15 21:19:25 +0100 | [diff] [blame] | 1525 | |
| 1526 | /* |
| 1527 | * Ensure we get a fresh copy of the ->key to prevent |
| 1528 | * race between exiting task and queue |
| 1529 | */ |
| 1530 | smp_read_barrier_depends(); |
| 1531 | if (cic->key) |
| 1532 | __cfq_exit_single_io_context(cfqd, cic); |
| 1533 | |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1534 | spin_unlock_irqrestore(q->queue_lock, flags); |
Al Viro | 12a0573 | 2006-03-18 13:38:01 -0500 | [diff] [blame] | 1535 | } |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1536 | } |
| 1537 | |
Jens Axboe | 498d3aa2 | 2007-04-26 12:54:48 +0200 | [diff] [blame] | 1538 | /* |
| 1539 | * The process that ioc belongs to has exited, we need to clean up |
| 1540 | * and put the internal structures we have that belongs to that process. |
| 1541 | */ |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1542 | static void cfq_exit_io_context(struct io_context *ioc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1543 | { |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1544 | call_for_each_cic(ioc, cfq_exit_single_io_context); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1545 | } |
| 1546 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1547 | static struct cfq_io_context * |
Al Viro | 8267e26 | 2005-10-21 03:20:53 -0400 | [diff] [blame] | 1548 | cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1549 | { |
Jens Axboe | b5deef9 | 2006-07-19 23:39:40 +0200 | [diff] [blame] | 1550 | struct cfq_io_context *cic; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1551 | |
Christoph Lameter | 94f6030 | 2007-07-17 04:03:29 -0700 | [diff] [blame] | 1552 | cic = kmem_cache_alloc_node(cfq_ioc_pool, gfp_mask | __GFP_ZERO, |
| 1553 | cfqd->queue->node); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1554 | if (cic) { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1555 | cic->last_end_request = jiffies; |
Jens Axboe | 553698f | 2006-06-14 19:11:57 +0200 | [diff] [blame] | 1556 | INIT_LIST_HEAD(&cic->queue_list); |
Jens Axboe | ffc4e75 | 2008-02-19 10:02:29 +0100 | [diff] [blame] | 1557 | INIT_HLIST_NODE(&cic->cic_list); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1558 | cic->dtor = cfq_free_io_context; |
| 1559 | cic->exit = cfq_exit_io_context; |
Jens Axboe | 4050cf1 | 2006-07-19 05:07:12 +0200 | [diff] [blame] | 1560 | elv_ioc_count_inc(ioc_count); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1561 | } |
| 1562 | |
| 1563 | return cic; |
| 1564 | } |
| 1565 | |
Jens Axboe | fd0928d | 2008-01-24 08:52:45 +0100 | [diff] [blame] | 1566 | static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1567 | { |
| 1568 | struct task_struct *tsk = current; |
| 1569 | int ioprio_class; |
| 1570 | |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1571 | if (!cfq_cfqq_prio_changed(cfqq)) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1572 | return; |
| 1573 | |
Jens Axboe | fd0928d | 2008-01-24 08:52:45 +0100 | [diff] [blame] | 1574 | ioprio_class = IOPRIO_PRIO_CLASS(ioc->ioprio); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1575 | switch (ioprio_class) { |
Jens Axboe | fe094d9 | 2008-01-31 13:08:54 +0100 | [diff] [blame] | 1576 | default: |
| 1577 | printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class); |
| 1578 | case IOPRIO_CLASS_NONE: |
| 1579 | /* |
Jens Axboe | 6d63c27 | 2008-05-07 09:51:23 +0200 | [diff] [blame] | 1580 | * no prio set, inherit CPU scheduling settings |
Jens Axboe | fe094d9 | 2008-01-31 13:08:54 +0100 | [diff] [blame] | 1581 | */ |
| 1582 | cfqq->ioprio = task_nice_ioprio(tsk); |
Jens Axboe | 6d63c27 | 2008-05-07 09:51:23 +0200 | [diff] [blame] | 1583 | cfqq->ioprio_class = task_nice_ioclass(tsk); |
Jens Axboe | fe094d9 | 2008-01-31 13:08:54 +0100 | [diff] [blame] | 1584 | break; |
| 1585 | case IOPRIO_CLASS_RT: |
| 1586 | cfqq->ioprio = task_ioprio(ioc); |
| 1587 | cfqq->ioprio_class = IOPRIO_CLASS_RT; |
| 1588 | break; |
| 1589 | case IOPRIO_CLASS_BE: |
| 1590 | cfqq->ioprio = task_ioprio(ioc); |
| 1591 | cfqq->ioprio_class = IOPRIO_CLASS_BE; |
| 1592 | break; |
| 1593 | case IOPRIO_CLASS_IDLE: |
| 1594 | cfqq->ioprio_class = IOPRIO_CLASS_IDLE; |
| 1595 | cfqq->ioprio = 7; |
| 1596 | cfq_clear_cfqq_idle_window(cfqq); |
| 1597 | break; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1598 | } |
| 1599 | |
| 1600 | /* |
| 1601 | * keep track of original prio settings in case we have to temporarily |
| 1602 | * elevate the priority of this queue |
| 1603 | */ |
| 1604 | cfqq->org_ioprio = cfqq->ioprio; |
| 1605 | cfqq->org_ioprio_class = cfqq->ioprio_class; |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1606 | cfq_clear_cfqq_prio_changed(cfqq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1607 | } |
| 1608 | |
Jens Axboe | febffd6 | 2008-01-28 13:19:43 +0100 | [diff] [blame] | 1609 | static void changed_ioprio(struct io_context *ioc, struct cfq_io_context *cic) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1610 | { |
Al Viro | 478a82b | 2006-03-18 13:25:24 -0500 | [diff] [blame] | 1611 | struct cfq_data *cfqd = cic->key; |
| 1612 | struct cfq_queue *cfqq; |
Jens Axboe | c1b707d | 2006-10-30 19:54:23 +0100 | [diff] [blame] | 1613 | unsigned long flags; |
Jens Axboe | 35e6077 | 2006-06-14 09:10:45 +0200 | [diff] [blame] | 1614 | |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 1615 | if (unlikely(!cfqd)) |
| 1616 | return; |
| 1617 | |
Jens Axboe | c1b707d | 2006-10-30 19:54:23 +0100 | [diff] [blame] | 1618 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 1619 | |
Jens Axboe | ff6657c | 2009-04-08 10:58:57 +0200 | [diff] [blame] | 1620 | cfqq = cic->cfqq[BLK_RW_ASYNC]; |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 1621 | if (cfqq) { |
| 1622 | struct cfq_queue *new_cfqq; |
Jens Axboe | ff6657c | 2009-04-08 10:58:57 +0200 | [diff] [blame] | 1623 | new_cfqq = cfq_get_queue(cfqd, BLK_RW_ASYNC, cic->ioc, |
| 1624 | GFP_ATOMIC); |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 1625 | if (new_cfqq) { |
Jens Axboe | ff6657c | 2009-04-08 10:58:57 +0200 | [diff] [blame] | 1626 | cic->cfqq[BLK_RW_ASYNC] = new_cfqq; |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 1627 | cfq_put_queue(cfqq); |
| 1628 | } |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1629 | } |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 1630 | |
Jens Axboe | ff6657c | 2009-04-08 10:58:57 +0200 | [diff] [blame] | 1631 | cfqq = cic->cfqq[BLK_RW_SYNC]; |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 1632 | if (cfqq) |
| 1633 | cfq_mark_cfqq_prio_changed(cfqq); |
| 1634 | |
Jens Axboe | c1b707d | 2006-10-30 19:54:23 +0100 | [diff] [blame] | 1635 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1636 | } |
| 1637 | |
Jens Axboe | fc46379 | 2006-08-29 09:05:44 +0200 | [diff] [blame] | 1638 | static void cfq_ioc_set_ioprio(struct io_context *ioc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1639 | { |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1640 | call_for_each_cic(ioc, changed_ioprio); |
Jens Axboe | fc46379 | 2006-08-29 09:05:44 +0200 | [diff] [blame] | 1641 | ioc->ioprio_changed = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1642 | } |
| 1643 | |
| 1644 | static struct cfq_queue * |
Jens Axboe | 15c31be | 2007-07-10 13:43:25 +0200 | [diff] [blame] | 1645 | cfq_find_alloc_queue(struct cfq_data *cfqd, int is_sync, |
Jens Axboe | fd0928d | 2008-01-24 08:52:45 +0100 | [diff] [blame] | 1646 | struct io_context *ioc, gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1647 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1648 | struct cfq_queue *cfqq, *new_cfqq = NULL; |
Vasily Tarasov | 91fac31 | 2007-04-25 12:29:51 +0200 | [diff] [blame] | 1649 | struct cfq_io_context *cic; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1650 | |
| 1651 | retry: |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1652 | cic = cfq_cic_lookup(cfqd, ioc); |
Vasily Tarasov | 91fac31 | 2007-04-25 12:29:51 +0200 | [diff] [blame] | 1653 | /* cic always exists here */ |
| 1654 | cfqq = cic_to_cfqq(cic, is_sync); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1655 | |
| 1656 | if (!cfqq) { |
| 1657 | if (new_cfqq) { |
| 1658 | cfqq = new_cfqq; |
| 1659 | new_cfqq = NULL; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1660 | } else if (gfp_mask & __GFP_WAIT) { |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 1661 | /* |
| 1662 | * Inform the allocator of the fact that we will |
| 1663 | * just repeat this allocation if it fails, to allow |
| 1664 | * the allocator to do whatever it needs to attempt to |
| 1665 | * free memory. |
| 1666 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1667 | spin_unlock_irq(cfqd->queue->queue_lock); |
Christoph Lameter | 94f6030 | 2007-07-17 04:03:29 -0700 | [diff] [blame] | 1668 | new_cfqq = kmem_cache_alloc_node(cfq_pool, |
| 1669 | gfp_mask | __GFP_NOFAIL | __GFP_ZERO, |
| 1670 | cfqd->queue->node); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1671 | spin_lock_irq(cfqd->queue->queue_lock); |
| 1672 | goto retry; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1673 | } else { |
Christoph Lameter | 94f6030 | 2007-07-17 04:03:29 -0700 | [diff] [blame] | 1674 | cfqq = kmem_cache_alloc_node(cfq_pool, |
| 1675 | gfp_mask | __GFP_ZERO, |
| 1676 | cfqd->queue->node); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1677 | if (!cfqq) |
| 1678 | goto out; |
Kiyoshi Ueda | db3b584 | 2005-06-17 16:15:10 +0200 | [diff] [blame] | 1679 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1680 | |
Jens Axboe | d9e7620 | 2007-04-20 14:27:50 +0200 | [diff] [blame] | 1681 | RB_CLEAR_NODE(&cfqq->rb_node); |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 1682 | RB_CLEAR_NODE(&cfqq->p_node); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1683 | INIT_LIST_HEAD(&cfqq->fifo); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1684 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1685 | atomic_set(&cfqq->ref, 0); |
| 1686 | cfqq->cfqd = cfqd; |
Jens Axboe | c5b680f | 2007-01-19 11:56:49 +1100 | [diff] [blame] | 1687 | |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 1688 | cfq_mark_cfqq_prio_changed(cfqq); |
Vasily Tarasov | 91fac31 | 2007-04-25 12:29:51 +0200 | [diff] [blame] | 1689 | |
Jens Axboe | fd0928d | 2008-01-24 08:52:45 +0100 | [diff] [blame] | 1690 | cfq_init_prio_data(cfqq, ioc); |
Jens Axboe | 0871714 | 2008-01-28 11:38:15 +0100 | [diff] [blame] | 1691 | |
| 1692 | if (is_sync) { |
| 1693 | if (!cfq_class_idle(cfqq)) |
| 1694 | cfq_mark_cfqq_idle_window(cfqq); |
| 1695 | cfq_mark_cfqq_sync(cfqq); |
| 1696 | } |
Jens Axboe | 7b67913 | 2008-05-30 12:23:07 +0200 | [diff] [blame] | 1697 | cfqq->pid = current->pid; |
| 1698 | cfq_log_cfqq(cfqd, cfqq, "alloced"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1699 | } |
| 1700 | |
| 1701 | if (new_cfqq) |
| 1702 | kmem_cache_free(cfq_pool, new_cfqq); |
| 1703 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1704 | out: |
| 1705 | WARN_ON((gfp_mask & __GFP_WAIT) && !cfqq); |
| 1706 | return cfqq; |
| 1707 | } |
| 1708 | |
Vasily Tarasov | c2dea2d | 2007-07-20 10:06:38 +0200 | [diff] [blame] | 1709 | static struct cfq_queue ** |
| 1710 | cfq_async_queue_prio(struct cfq_data *cfqd, int ioprio_class, int ioprio) |
| 1711 | { |
Jens Axboe | fe094d9 | 2008-01-31 13:08:54 +0100 | [diff] [blame] | 1712 | switch (ioprio_class) { |
Vasily Tarasov | c2dea2d | 2007-07-20 10:06:38 +0200 | [diff] [blame] | 1713 | case IOPRIO_CLASS_RT: |
| 1714 | return &cfqd->async_cfqq[0][ioprio]; |
| 1715 | case IOPRIO_CLASS_BE: |
| 1716 | return &cfqd->async_cfqq[1][ioprio]; |
| 1717 | case IOPRIO_CLASS_IDLE: |
| 1718 | return &cfqd->async_idle_cfqq; |
| 1719 | default: |
| 1720 | BUG(); |
| 1721 | } |
| 1722 | } |
| 1723 | |
Jens Axboe | 15c31be | 2007-07-10 13:43:25 +0200 | [diff] [blame] | 1724 | static struct cfq_queue * |
Jens Axboe | fd0928d | 2008-01-24 08:52:45 +0100 | [diff] [blame] | 1725 | cfq_get_queue(struct cfq_data *cfqd, int is_sync, struct io_context *ioc, |
Jens Axboe | 15c31be | 2007-07-10 13:43:25 +0200 | [diff] [blame] | 1726 | gfp_t gfp_mask) |
| 1727 | { |
Jens Axboe | fd0928d | 2008-01-24 08:52:45 +0100 | [diff] [blame] | 1728 | const int ioprio = task_ioprio(ioc); |
| 1729 | const int ioprio_class = task_ioprio_class(ioc); |
Vasily Tarasov | c2dea2d | 2007-07-20 10:06:38 +0200 | [diff] [blame] | 1730 | struct cfq_queue **async_cfqq = NULL; |
Jens Axboe | 15c31be | 2007-07-10 13:43:25 +0200 | [diff] [blame] | 1731 | struct cfq_queue *cfqq = NULL; |
| 1732 | |
Vasily Tarasov | c2dea2d | 2007-07-20 10:06:38 +0200 | [diff] [blame] | 1733 | if (!is_sync) { |
| 1734 | async_cfqq = cfq_async_queue_prio(cfqd, ioprio_class, ioprio); |
| 1735 | cfqq = *async_cfqq; |
| 1736 | } |
| 1737 | |
Oleg Nesterov | 0a0836a | 2007-10-23 15:08:21 +0200 | [diff] [blame] | 1738 | if (!cfqq) { |
Jens Axboe | fd0928d | 2008-01-24 08:52:45 +0100 | [diff] [blame] | 1739 | cfqq = cfq_find_alloc_queue(cfqd, is_sync, ioc, gfp_mask); |
Oleg Nesterov | 0a0836a | 2007-10-23 15:08:21 +0200 | [diff] [blame] | 1740 | if (!cfqq) |
| 1741 | return NULL; |
| 1742 | } |
Jens Axboe | 15c31be | 2007-07-10 13:43:25 +0200 | [diff] [blame] | 1743 | |
| 1744 | /* |
| 1745 | * pin the queue now that it's allocated, scheduler exit will prune it |
| 1746 | */ |
Vasily Tarasov | c2dea2d | 2007-07-20 10:06:38 +0200 | [diff] [blame] | 1747 | if (!is_sync && !(*async_cfqq)) { |
Jens Axboe | 15c31be | 2007-07-10 13:43:25 +0200 | [diff] [blame] | 1748 | atomic_inc(&cfqq->ref); |
Vasily Tarasov | c2dea2d | 2007-07-20 10:06:38 +0200 | [diff] [blame] | 1749 | *async_cfqq = cfqq; |
Jens Axboe | 15c31be | 2007-07-10 13:43:25 +0200 | [diff] [blame] | 1750 | } |
| 1751 | |
| 1752 | atomic_inc(&cfqq->ref); |
| 1753 | return cfqq; |
| 1754 | } |
| 1755 | |
Jens Axboe | 498d3aa2 | 2007-04-26 12:54:48 +0200 | [diff] [blame] | 1756 | /* |
| 1757 | * We drop cfq io contexts lazily, so we may find a dead one. |
| 1758 | */ |
OGAWA Hirofumi | dbecf3a | 2006-04-18 09:45:18 +0200 | [diff] [blame] | 1759 | static void |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1760 | cfq_drop_dead_cic(struct cfq_data *cfqd, struct io_context *ioc, |
| 1761 | struct cfq_io_context *cic) |
OGAWA Hirofumi | dbecf3a | 2006-04-18 09:45:18 +0200 | [diff] [blame] | 1762 | { |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1763 | unsigned long flags; |
| 1764 | |
Jens Axboe | fc46379 | 2006-08-29 09:05:44 +0200 | [diff] [blame] | 1765 | WARN_ON(!list_empty(&cic->queue_list)); |
Jens Axboe | 597bc48 | 2007-04-24 21:23:53 +0200 | [diff] [blame] | 1766 | |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1767 | spin_lock_irqsave(&ioc->lock, flags); |
Jens Axboe | 597bc48 | 2007-04-24 21:23:53 +0200 | [diff] [blame] | 1768 | |
Fabio Checconi | 4faa3c8 | 2008-04-10 08:28:01 +0200 | [diff] [blame] | 1769 | BUG_ON(ioc->ioc_data == cic); |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1770 | |
| 1771 | radix_tree_delete(&ioc->radix_root, (unsigned long) cfqd); |
Jens Axboe | ffc4e75 | 2008-02-19 10:02:29 +0100 | [diff] [blame] | 1772 | hlist_del_rcu(&cic->cic_list); |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1773 | spin_unlock_irqrestore(&ioc->lock, flags); |
| 1774 | |
| 1775 | cfq_cic_free(cic); |
OGAWA Hirofumi | dbecf3a | 2006-04-18 09:45:18 +0200 | [diff] [blame] | 1776 | } |
| 1777 | |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1778 | static struct cfq_io_context * |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1779 | cfq_cic_lookup(struct cfq_data *cfqd, struct io_context *ioc) |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1780 | { |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1781 | struct cfq_io_context *cic; |
Jens Axboe | d6de8be | 2008-05-28 14:46:59 +0200 | [diff] [blame] | 1782 | unsigned long flags; |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1783 | void *k; |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1784 | |
Vasily Tarasov | 91fac31 | 2007-04-25 12:29:51 +0200 | [diff] [blame] | 1785 | if (unlikely(!ioc)) |
| 1786 | return NULL; |
| 1787 | |
Jens Axboe | d6de8be | 2008-05-28 14:46:59 +0200 | [diff] [blame] | 1788 | rcu_read_lock(); |
| 1789 | |
Jens Axboe | 597bc48 | 2007-04-24 21:23:53 +0200 | [diff] [blame] | 1790 | /* |
| 1791 | * we maintain a last-hit cache, to avoid browsing over the tree |
| 1792 | */ |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1793 | cic = rcu_dereference(ioc->ioc_data); |
Jens Axboe | d6de8be | 2008-05-28 14:46:59 +0200 | [diff] [blame] | 1794 | if (cic && cic->key == cfqd) { |
| 1795 | rcu_read_unlock(); |
Jens Axboe | 597bc48 | 2007-04-24 21:23:53 +0200 | [diff] [blame] | 1796 | return cic; |
Jens Axboe | d6de8be | 2008-05-28 14:46:59 +0200 | [diff] [blame] | 1797 | } |
Jens Axboe | 597bc48 | 2007-04-24 21:23:53 +0200 | [diff] [blame] | 1798 | |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1799 | do { |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1800 | cic = radix_tree_lookup(&ioc->radix_root, (unsigned long) cfqd); |
| 1801 | rcu_read_unlock(); |
| 1802 | if (!cic) |
| 1803 | break; |
OGAWA Hirofumi | be3b075 | 2006-04-18 19:18:31 +0200 | [diff] [blame] | 1804 | /* ->key must be copied to avoid race with cfq_exit_queue() */ |
| 1805 | k = cic->key; |
| 1806 | if (unlikely(!k)) { |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1807 | cfq_drop_dead_cic(cfqd, ioc, cic); |
Jens Axboe | d6de8be | 2008-05-28 14:46:59 +0200 | [diff] [blame] | 1808 | rcu_read_lock(); |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1809 | continue; |
OGAWA Hirofumi | dbecf3a | 2006-04-18 09:45:18 +0200 | [diff] [blame] | 1810 | } |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1811 | |
Jens Axboe | d6de8be | 2008-05-28 14:46:59 +0200 | [diff] [blame] | 1812 | spin_lock_irqsave(&ioc->lock, flags); |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1813 | rcu_assign_pointer(ioc->ioc_data, cic); |
Jens Axboe | d6de8be | 2008-05-28 14:46:59 +0200 | [diff] [blame] | 1814 | spin_unlock_irqrestore(&ioc->lock, flags); |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1815 | break; |
| 1816 | } while (1); |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1817 | |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1818 | return cic; |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1819 | } |
| 1820 | |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1821 | /* |
| 1822 | * Add cic into ioc, using cfqd as the search key. This enables us to lookup |
| 1823 | * the process specific cfq io context when entered from the block layer. |
| 1824 | * Also adds the cic to a per-cfqd list, used when this queue is removed. |
| 1825 | */ |
Jens Axboe | febffd6 | 2008-01-28 13:19:43 +0100 | [diff] [blame] | 1826 | static int cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc, |
| 1827 | struct cfq_io_context *cic, gfp_t gfp_mask) |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1828 | { |
Jens Axboe | 0261d68 | 2006-10-30 19:07:48 +0100 | [diff] [blame] | 1829 | unsigned long flags; |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1830 | int ret; |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1831 | |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1832 | ret = radix_tree_preload(gfp_mask); |
| 1833 | if (!ret) { |
| 1834 | cic->ioc = ioc; |
| 1835 | cic->key = cfqd; |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1836 | |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1837 | spin_lock_irqsave(&ioc->lock, flags); |
| 1838 | ret = radix_tree_insert(&ioc->radix_root, |
| 1839 | (unsigned long) cfqd, cic); |
Jens Axboe | ffc4e75 | 2008-02-19 10:02:29 +0100 | [diff] [blame] | 1840 | if (!ret) |
| 1841 | hlist_add_head_rcu(&cic->cic_list, &ioc->cic_list); |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1842 | spin_unlock_irqrestore(&ioc->lock, flags); |
| 1843 | |
| 1844 | radix_tree_preload_end(); |
| 1845 | |
| 1846 | if (!ret) { |
| 1847 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); |
| 1848 | list_add(&cic->queue_list, &cfqd->cic_list); |
| 1849 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); |
OGAWA Hirofumi | dbecf3a | 2006-04-18 09:45:18 +0200 | [diff] [blame] | 1850 | } |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1851 | } |
| 1852 | |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1853 | if (ret) |
| 1854 | printk(KERN_ERR "cfq: cic link failed!\n"); |
Jens Axboe | fc46379 | 2006-08-29 09:05:44 +0200 | [diff] [blame] | 1855 | |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1856 | return ret; |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1857 | } |
| 1858 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1859 | /* |
| 1860 | * Setup general io context and cfq io context. There can be several cfq |
| 1861 | * 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] | 1862 | * than one device managed by cfq. |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1863 | */ |
| 1864 | static struct cfq_io_context * |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1865 | cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1866 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1867 | struct io_context *ioc = NULL; |
| 1868 | struct cfq_io_context *cic; |
| 1869 | |
| 1870 | might_sleep_if(gfp_mask & __GFP_WAIT); |
| 1871 | |
Jens Axboe | b5deef9 | 2006-07-19 23:39:40 +0200 | [diff] [blame] | 1872 | ioc = get_io_context(gfp_mask, cfqd->queue->node); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1873 | if (!ioc) |
| 1874 | return NULL; |
| 1875 | |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1876 | cic = cfq_cic_lookup(cfqd, ioc); |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1877 | if (cic) |
| 1878 | goto out; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1879 | |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 1880 | cic = cfq_alloc_io_context(cfqd, gfp_mask); |
| 1881 | if (cic == NULL) |
| 1882 | goto err; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1883 | |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1884 | if (cfq_cic_link(cfqd, ioc, cic, gfp_mask)) |
| 1885 | goto err_free; |
| 1886 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1887 | out: |
Jens Axboe | fc46379 | 2006-08-29 09:05:44 +0200 | [diff] [blame] | 1888 | smp_read_barrier_depends(); |
| 1889 | if (unlikely(ioc->ioprio_changed)) |
| 1890 | cfq_ioc_set_ioprio(ioc); |
| 1891 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1892 | return cic; |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 1893 | err_free: |
| 1894 | cfq_cic_free(cic); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1895 | err: |
| 1896 | put_io_context(ioc); |
| 1897 | return NULL; |
| 1898 | } |
| 1899 | |
| 1900 | static void |
| 1901 | cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic) |
| 1902 | { |
Jens Axboe | aaf1228 | 2007-01-19 11:30:16 +1100 | [diff] [blame] | 1903 | unsigned long elapsed = jiffies - cic->last_end_request; |
| 1904 | unsigned long ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1905 | |
| 1906 | cic->ttime_samples = (7*cic->ttime_samples + 256) / 8; |
| 1907 | cic->ttime_total = (7*cic->ttime_total + 256*ttime) / 8; |
| 1908 | cic->ttime_mean = (cic->ttime_total + 128) / cic->ttime_samples; |
| 1909 | } |
| 1910 | |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 1911 | static void |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 1912 | cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_io_context *cic, |
| 1913 | struct request *rq) |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 1914 | { |
| 1915 | sector_t sdist; |
| 1916 | u64 total; |
| 1917 | |
Jeff Moyer | 4d00aa4 | 2009-04-21 07:25:04 +0200 | [diff] [blame] | 1918 | if (!cic->last_request_pos) |
| 1919 | sdist = 0; |
Tejun Heo | 83096eb | 2009-05-07 22:24:39 +0900 | [diff] [blame] | 1920 | else if (cic->last_request_pos < blk_rq_pos(rq)) |
| 1921 | sdist = blk_rq_pos(rq) - cic->last_request_pos; |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 1922 | else |
Tejun Heo | 83096eb | 2009-05-07 22:24:39 +0900 | [diff] [blame] | 1923 | sdist = cic->last_request_pos - blk_rq_pos(rq); |
Jens Axboe | 206dc69 | 2006-03-28 13:03:44 +0200 | [diff] [blame] | 1924 | |
| 1925 | /* |
| 1926 | * Don't allow the seek distance to get too large from the |
| 1927 | * odd fragment, pagein, etc |
| 1928 | */ |
| 1929 | if (cic->seek_samples <= 60) /* second&third seek */ |
| 1930 | sdist = min(sdist, (cic->seek_mean * 4) + 2*1024*1024); |
| 1931 | else |
| 1932 | sdist = min(sdist, (cic->seek_mean * 4) + 2*1024*64); |
| 1933 | |
| 1934 | cic->seek_samples = (7*cic->seek_samples + 256) / 8; |
| 1935 | cic->seek_total = (7*cic->seek_total + (u64)256*sdist) / 8; |
| 1936 | total = cic->seek_total + (cic->seek_samples/2); |
| 1937 | do_div(total, cic->seek_samples); |
| 1938 | cic->seek_mean = (sector_t)total; |
| 1939 | } |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1940 | |
| 1941 | /* |
| 1942 | * Disable idle window if the process thinks too long or seeks so much that |
| 1943 | * it doesn't matter |
| 1944 | */ |
| 1945 | static void |
| 1946 | cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
| 1947 | struct cfq_io_context *cic) |
| 1948 | { |
Jens Axboe | 7b67913 | 2008-05-30 12:23:07 +0200 | [diff] [blame] | 1949 | int old_idle, enable_idle; |
Jens Axboe | 1be92f2f | 2007-04-19 14:32:26 +0200 | [diff] [blame] | 1950 | |
Jens Axboe | 0871714 | 2008-01-28 11:38:15 +0100 | [diff] [blame] | 1951 | /* |
| 1952 | * Don't idle for async or idle io prio class |
| 1953 | */ |
| 1954 | if (!cfq_cfqq_sync(cfqq) || cfq_class_idle(cfqq)) |
Jens Axboe | 1be92f2f | 2007-04-19 14:32:26 +0200 | [diff] [blame] | 1955 | return; |
| 1956 | |
Jens Axboe | c265a7f | 2008-06-26 13:49:33 +0200 | [diff] [blame] | 1957 | enable_idle = old_idle = cfq_cfqq_idle_window(cfqq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1958 | |
Nikanth Karthikesan | 66dac98 | 2007-11-27 12:47:04 +0100 | [diff] [blame] | 1959 | if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle || |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 1960 | (cfqd->hw_tag && CIC_SEEKY(cic))) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1961 | enable_idle = 0; |
| 1962 | else if (sample_valid(cic->ttime_samples)) { |
| 1963 | if (cic->ttime_mean > cfqd->cfq_slice_idle) |
| 1964 | enable_idle = 0; |
| 1965 | else |
| 1966 | enable_idle = 1; |
| 1967 | } |
| 1968 | |
Jens Axboe | 7b67913 | 2008-05-30 12:23:07 +0200 | [diff] [blame] | 1969 | if (old_idle != enable_idle) { |
| 1970 | cfq_log_cfqq(cfqd, cfqq, "idle=%d", enable_idle); |
| 1971 | if (enable_idle) |
| 1972 | cfq_mark_cfqq_idle_window(cfqq); |
| 1973 | else |
| 1974 | cfq_clear_cfqq_idle_window(cfqq); |
| 1975 | } |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1976 | } |
| 1977 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1978 | /* |
| 1979 | * Check if new_cfqq should preempt the currently active queue. Return 0 for |
| 1980 | * no or if we aren't sure, a 1 will cause a preempt. |
| 1981 | */ |
| 1982 | static int |
| 1983 | cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 1984 | struct request *rq) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1985 | { |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 1986 | struct cfq_queue *cfqq; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1987 | |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 1988 | cfqq = cfqd->active_queue; |
| 1989 | if (!cfqq) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1990 | return 0; |
| 1991 | |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 1992 | if (cfq_slice_used(cfqq)) |
| 1993 | return 1; |
| 1994 | |
| 1995 | if (cfq_class_idle(new_cfqq)) |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 1996 | return 0; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1997 | |
| 1998 | if (cfq_class_idle(cfqq)) |
| 1999 | return 1; |
Jens Axboe | 1e3335d | 2007-02-14 19:59:49 +0100 | [diff] [blame] | 2000 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2001 | /* |
Jens Axboe | 374f84a | 2006-07-23 01:42:19 +0200 | [diff] [blame] | 2002 | * if the new request is sync, but the currently running queue is |
| 2003 | * not, let the sync request have priority. |
| 2004 | */ |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 2005 | if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq)) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2006 | return 1; |
Jens Axboe | 1e3335d | 2007-02-14 19:59:49 +0100 | [diff] [blame] | 2007 | |
Jens Axboe | 374f84a | 2006-07-23 01:42:19 +0200 | [diff] [blame] | 2008 | /* |
| 2009 | * So both queues are sync. Let the new request get disk time if |
| 2010 | * it's a metadata request and the current queue is doing regular IO. |
| 2011 | */ |
| 2012 | if (rq_is_meta(rq) && !cfqq->meta_pending) |
| 2013 | return 1; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2014 | |
Divyesh Shah | 3a9a3f6 | 2009-01-30 12:46:41 +0100 | [diff] [blame] | 2015 | /* |
| 2016 | * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice. |
| 2017 | */ |
| 2018 | if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq)) |
| 2019 | return 1; |
| 2020 | |
Jens Axboe | 1e3335d | 2007-02-14 19:59:49 +0100 | [diff] [blame] | 2021 | if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq)) |
| 2022 | return 0; |
| 2023 | |
| 2024 | /* |
| 2025 | * if this request is as-good as one we would expect from the |
| 2026 | * current cfqq, let it preempt |
| 2027 | */ |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 2028 | if (cfq_rq_close(cfqd, rq)) |
Jens Axboe | 1e3335d | 2007-02-14 19:59:49 +0100 | [diff] [blame] | 2029 | return 1; |
| 2030 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2031 | return 0; |
| 2032 | } |
| 2033 | |
| 2034 | /* |
| 2035 | * cfqq preempts the active queue. if we allowed preempt with no slice left, |
| 2036 | * let it have half of its nominal slice. |
| 2037 | */ |
| 2038 | static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
| 2039 | { |
Jens Axboe | 7b67913 | 2008-05-30 12:23:07 +0200 | [diff] [blame] | 2040 | cfq_log_cfqq(cfqd, cfqq, "preempt"); |
Jens Axboe | 6084cdd | 2007-04-23 08:25:00 +0200 | [diff] [blame] | 2041 | cfq_slice_expired(cfqd, 1); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2042 | |
Jens Axboe | bf57225 | 2006-07-19 20:29:12 +0200 | [diff] [blame] | 2043 | /* |
| 2044 | * Put the new queue at the front of the of the current list, |
| 2045 | * so we know that it will be selected next. |
| 2046 | */ |
| 2047 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
Jens Axboe | edd75ff | 2007-04-19 12:03:34 +0200 | [diff] [blame] | 2048 | |
| 2049 | cfq_service_tree_add(cfqd, cfqq, 1); |
Jens Axboe | bf57225 | 2006-07-19 20:29:12 +0200 | [diff] [blame] | 2050 | |
Jens Axboe | 44f7c16 | 2007-01-19 11:51:58 +1100 | [diff] [blame] | 2051 | cfqq->slice_end = 0; |
| 2052 | cfq_mark_cfqq_slice_new(cfqq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2053 | } |
| 2054 | |
| 2055 | /* |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 2056 | * 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] | 2057 | * something we should do about it |
| 2058 | */ |
| 2059 | static void |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 2060 | cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
| 2061 | struct request *rq) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2062 | { |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 2063 | struct cfq_io_context *cic = RQ_CIC(rq); |
Jens Axboe | 12e9fdd | 2006-06-01 10:09:56 +0200 | [diff] [blame] | 2064 | |
Aaron Carroll | 45333d5 | 2008-08-26 15:52:36 +0200 | [diff] [blame] | 2065 | cfqd->rq_queued++; |
Jens Axboe | 374f84a | 2006-07-23 01:42:19 +0200 | [diff] [blame] | 2066 | if (rq_is_meta(rq)) |
| 2067 | cfqq->meta_pending++; |
| 2068 | |
Jens Axboe | 9c2c38a | 2005-08-24 14:57:54 +0200 | [diff] [blame] | 2069 | cfq_update_io_thinktime(cfqd, cic); |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 2070 | cfq_update_io_seektime(cfqd, cic, rq); |
Jens Axboe | 9c2c38a | 2005-08-24 14:57:54 +0200 | [diff] [blame] | 2071 | cfq_update_idle_window(cfqd, cfqq, cic); |
| 2072 | |
Tejun Heo | 83096eb | 2009-05-07 22:24:39 +0900 | [diff] [blame] | 2073 | cic->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2074 | |
| 2075 | if (cfqq == cfqd->active_queue) { |
| 2076 | /* |
Jens Axboe | b029195 | 2009-04-07 11:38:31 +0200 | [diff] [blame] | 2077 | * Remember that we saw a request from this process, but |
| 2078 | * don't start queuing just yet. Otherwise we risk seeing lots |
| 2079 | * of tiny requests, because we disrupt the normal plugging |
Jens Axboe | d6ceb25 | 2009-04-14 14:18:16 +0200 | [diff] [blame] | 2080 | * and merging. If the request is already larger than a single |
| 2081 | * page, let it rip immediately. For that case we assume that |
Jens Axboe | 2d87072 | 2009-04-15 12:12:46 +0200 | [diff] [blame] | 2082 | * merging is already done. Ditto for a busy system that |
| 2083 | * has other work pending, don't risk delaying until the |
| 2084 | * idle timer unplug to continue working. |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2085 | */ |
Jens Axboe | d6ceb25 | 2009-04-14 14:18:16 +0200 | [diff] [blame] | 2086 | if (cfq_cfqq_wait_request(cfqq)) { |
Jens Axboe | 2d87072 | 2009-04-15 12:12:46 +0200 | [diff] [blame] | 2087 | if (blk_rq_bytes(rq) > PAGE_CACHE_SIZE || |
| 2088 | cfqd->busy_queues > 1) { |
Jens Axboe | d6ceb25 | 2009-04-14 14:18:16 +0200 | [diff] [blame] | 2089 | del_timer(&cfqd->idle_slice_timer); |
Tejun Heo | a7f5579 | 2009-04-23 11:05:17 +0900 | [diff] [blame] | 2090 | __blk_run_queue(cfqd->queue); |
Jens Axboe | d6ceb25 | 2009-04-14 14:18:16 +0200 | [diff] [blame] | 2091 | } |
Jens Axboe | b029195 | 2009-04-07 11:38:31 +0200 | [diff] [blame] | 2092 | cfq_mark_cfqq_must_dispatch(cfqq); |
Jens Axboe | d6ceb25 | 2009-04-14 14:18:16 +0200 | [diff] [blame] | 2093 | } |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 2094 | } else if (cfq_should_preempt(cfqd, cfqq, rq)) { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2095 | /* |
| 2096 | * not the active queue - expire current slice if it is |
| 2097 | * idle and has expired it's mean thinktime or this new queue |
Divyesh Shah | 3a9a3f6 | 2009-01-30 12:46:41 +0100 | [diff] [blame] | 2098 | * has some old slice time left and is of higher priority or |
| 2099 | * this new queue is RT and the current one is BE |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2100 | */ |
| 2101 | cfq_preempt_queue(cfqd, cfqq); |
Tejun Heo | a7f5579 | 2009-04-23 11:05:17 +0900 | [diff] [blame] | 2102 | __blk_run_queue(cfqd->queue); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2103 | } |
| 2104 | } |
| 2105 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 2106 | static void cfq_insert_request(struct request_queue *q, struct request *rq) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2107 | { |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 2108 | struct cfq_data *cfqd = q->elevator->elevator_data; |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 2109 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2110 | |
Jens Axboe | 7b67913 | 2008-05-30 12:23:07 +0200 | [diff] [blame] | 2111 | cfq_log_cfqq(cfqd, cfqq, "insert_request"); |
Jens Axboe | fd0928d | 2008-01-24 08:52:45 +0100 | [diff] [blame] | 2112 | cfq_init_prio_data(cfqq, RQ_CIC(rq)->ioc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2113 | |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 2114 | cfq_add_rq_rb(rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2115 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2116 | list_add_tail(&rq->queuelist, &cfqq->fifo); |
| 2117 | |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 2118 | cfq_rq_enqueued(cfqd, cfqq, rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2119 | } |
| 2120 | |
Aaron Carroll | 45333d5 | 2008-08-26 15:52:36 +0200 | [diff] [blame] | 2121 | /* |
| 2122 | * Update hw_tag based on peak queue depth over 50 samples under |
| 2123 | * sufficient load. |
| 2124 | */ |
| 2125 | static void cfq_update_hw_tag(struct cfq_data *cfqd) |
| 2126 | { |
| 2127 | if (cfqd->rq_in_driver > cfqd->rq_in_driver_peak) |
| 2128 | cfqd->rq_in_driver_peak = cfqd->rq_in_driver; |
| 2129 | |
| 2130 | if (cfqd->rq_queued <= CFQ_HW_QUEUE_MIN && |
| 2131 | cfqd->rq_in_driver <= CFQ_HW_QUEUE_MIN) |
| 2132 | return; |
| 2133 | |
| 2134 | if (cfqd->hw_tag_samples++ < 50) |
| 2135 | return; |
| 2136 | |
| 2137 | if (cfqd->rq_in_driver_peak >= CFQ_HW_QUEUE_MIN) |
| 2138 | cfqd->hw_tag = 1; |
| 2139 | else |
| 2140 | cfqd->hw_tag = 0; |
| 2141 | |
| 2142 | cfqd->hw_tag_samples = 0; |
| 2143 | cfqd->rq_in_driver_peak = 0; |
| 2144 | } |
| 2145 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 2146 | static void cfq_completed_request(struct request_queue *q, struct request *rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2147 | { |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 2148 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 2149 | struct cfq_data *cfqd = cfqq->cfqd; |
Jens Axboe | 5380a10 | 2006-07-13 12:37:56 +0200 | [diff] [blame] | 2150 | const int sync = rq_is_sync(rq); |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 2151 | unsigned long now; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2152 | |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 2153 | now = jiffies; |
Jens Axboe | 7b67913 | 2008-05-30 12:23:07 +0200 | [diff] [blame] | 2154 | cfq_log_cfqq(cfqd, cfqq, "complete"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2155 | |
Aaron Carroll | 45333d5 | 2008-08-26 15:52:36 +0200 | [diff] [blame] | 2156 | cfq_update_hw_tag(cfqd); |
| 2157 | |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 2158 | WARN_ON(!cfqd->rq_in_driver); |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 2159 | WARN_ON(!cfqq->dispatched); |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 2160 | cfqd->rq_in_driver--; |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 2161 | cfqq->dispatched--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2162 | |
Jens Axboe | 3ed9a29 | 2007-04-23 08:33:33 +0200 | [diff] [blame] | 2163 | if (cfq_cfqq_sync(cfqq)) |
| 2164 | cfqd->sync_flight--; |
| 2165 | |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 2166 | if (sync) |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 2167 | RQ_CIC(rq)->last_end_request = now; |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 2168 | |
| 2169 | /* |
| 2170 | * If this is the active queue, check if it needs to be expired, |
| 2171 | * or if we want to idle in case it has no pending requests. |
| 2172 | */ |
| 2173 | if (cfqd->active_queue == cfqq) { |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 2174 | const bool cfqq_empty = RB_EMPTY_ROOT(&cfqq->sort_list); |
| 2175 | |
Jens Axboe | 44f7c16 | 2007-01-19 11:51:58 +1100 | [diff] [blame] | 2176 | if (cfq_cfqq_slice_new(cfqq)) { |
| 2177 | cfq_set_prio_slice(cfqd, cfqq); |
| 2178 | cfq_clear_cfqq_slice_new(cfqq); |
| 2179 | } |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 2180 | /* |
| 2181 | * If there are no requests waiting in this queue, and |
| 2182 | * there are other queues ready to issue requests, AND |
| 2183 | * those other queues are issuing requests within our |
| 2184 | * mean seek distance, give them a chance to run instead |
| 2185 | * of idling. |
| 2186 | */ |
Jens Axboe | 0871714 | 2008-01-28 11:38:15 +0100 | [diff] [blame] | 2187 | if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq)) |
Jens Axboe | 6084cdd | 2007-04-23 08:25:00 +0200 | [diff] [blame] | 2188 | cfq_slice_expired(cfqd, 1); |
Jens Axboe | a36e71f | 2009-04-15 12:15:11 +0200 | [diff] [blame] | 2189 | else if (cfqq_empty && !cfq_close_cooperator(cfqd, cfqq, 1) && |
| 2190 | sync && !rq_noidle(rq)) |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 2191 | cfq_arm_slice_timer(cfqd); |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 2192 | } |
Jens Axboe | 6d048f5 | 2007-04-25 12:44:27 +0200 | [diff] [blame] | 2193 | |
| 2194 | if (!cfqd->rq_in_driver) |
| 2195 | cfq_schedule_dispatch(cfqd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2196 | } |
| 2197 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2198 | /* |
| 2199 | * we temporarily boost lower priority queues if they are holding fs exclusive |
| 2200 | * resources. they are boosted to normal prio (CLASS_BE/4) |
| 2201 | */ |
| 2202 | static void cfq_prio_boost(struct cfq_queue *cfqq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2203 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2204 | if (has_fs_excl()) { |
| 2205 | /* |
| 2206 | * boost idle prio on transactions that would lock out other |
| 2207 | * users of the filesystem |
| 2208 | */ |
| 2209 | if (cfq_class_idle(cfqq)) |
| 2210 | cfqq->ioprio_class = IOPRIO_CLASS_BE; |
| 2211 | if (cfqq->ioprio > IOPRIO_NORM) |
| 2212 | cfqq->ioprio = IOPRIO_NORM; |
| 2213 | } else { |
| 2214 | /* |
| 2215 | * check if we need to unboost the queue |
| 2216 | */ |
| 2217 | if (cfqq->ioprio_class != cfqq->org_ioprio_class) |
| 2218 | cfqq->ioprio_class = cfqq->org_ioprio_class; |
| 2219 | if (cfqq->ioprio != cfqq->org_ioprio) |
| 2220 | cfqq->ioprio = cfqq->org_ioprio; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2221 | } |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2222 | } |
| 2223 | |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 2224 | static inline int __cfq_may_queue(struct cfq_queue *cfqq) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2225 | { |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 2226 | if ((cfq_cfqq_wait_request(cfqq) || cfq_cfqq_must_alloc(cfqq)) && |
Andrew Morton | 99f95e5 | 2005-06-27 20:14:05 -0700 | [diff] [blame] | 2227 | !cfq_cfqq_must_alloc_slice(cfqq)) { |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 2228 | cfq_mark_cfqq_must_alloc_slice(cfqq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2229 | return ELV_MQUEUE_MUST; |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 2230 | } |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2231 | |
| 2232 | return ELV_MQUEUE_MAY; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2233 | } |
| 2234 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 2235 | static int cfq_may_queue(struct request_queue *q, int rw) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2236 | { |
| 2237 | struct cfq_data *cfqd = q->elevator->elevator_data; |
| 2238 | struct task_struct *tsk = current; |
Vasily Tarasov | 91fac31 | 2007-04-25 12:29:51 +0200 | [diff] [blame] | 2239 | struct cfq_io_context *cic; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2240 | struct cfq_queue *cfqq; |
| 2241 | |
| 2242 | /* |
| 2243 | * don't force setup of a queue from here, as a call to may_queue |
| 2244 | * does not necessarily imply that a request actually will be queued. |
| 2245 | * so just lookup a possibly existing queue, or return 'may queue' |
| 2246 | * if that fails |
| 2247 | */ |
Jens Axboe | 4ac845a | 2008-01-24 08:44:49 +0100 | [diff] [blame] | 2248 | cic = cfq_cic_lookup(cfqd, tsk->io_context); |
Vasily Tarasov | 91fac31 | 2007-04-25 12:29:51 +0200 | [diff] [blame] | 2249 | if (!cic) |
| 2250 | return ELV_MQUEUE_MAY; |
| 2251 | |
Jens Axboe | b0b78f8 | 2009-04-08 10:56:08 +0200 | [diff] [blame] | 2252 | cfqq = cic_to_cfqq(cic, rw_is_sync(rw)); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2253 | if (cfqq) { |
Jens Axboe | fd0928d | 2008-01-24 08:52:45 +0100 | [diff] [blame] | 2254 | cfq_init_prio_data(cfqq, cic->ioc); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2255 | cfq_prio_boost(cfqq); |
| 2256 | |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 2257 | return __cfq_may_queue(cfqq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2258 | } |
| 2259 | |
| 2260 | return ELV_MQUEUE_MAY; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2261 | } |
| 2262 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2263 | /* |
| 2264 | * queue lock held here |
| 2265 | */ |
Jens Axboe | bb37b94 | 2006-12-01 10:42:33 +0100 | [diff] [blame] | 2266 | static void cfq_put_request(struct request *rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2267 | { |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 2268 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2269 | |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 2270 | if (cfqq) { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2271 | const int rw = rq_data_dir(rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2272 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2273 | BUG_ON(!cfqq->allocated[rw]); |
| 2274 | cfqq->allocated[rw]--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2275 | |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 2276 | put_io_context(RQ_CIC(rq)->ioc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2277 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2278 | rq->elevator_private = NULL; |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 2279 | rq->elevator_private2 = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2280 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2281 | cfq_put_queue(cfqq); |
| 2282 | } |
| 2283 | } |
| 2284 | |
| 2285 | /* |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2286 | * Allocate cfq data structures associated with this request. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2287 | */ |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2288 | static int |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 2289 | cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2290 | { |
| 2291 | struct cfq_data *cfqd = q->elevator->elevator_data; |
| 2292 | struct cfq_io_context *cic; |
| 2293 | const int rw = rq_data_dir(rq); |
Jens Axboe | 7749a8d | 2006-12-13 13:02:26 +0100 | [diff] [blame] | 2294 | const int is_sync = rq_is_sync(rq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2295 | struct cfq_queue *cfqq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2296 | unsigned long flags; |
| 2297 | |
| 2298 | might_sleep_if(gfp_mask & __GFP_WAIT); |
| 2299 | |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 2300 | cic = cfq_get_io_context(cfqd, gfp_mask); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2301 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2302 | spin_lock_irqsave(q->queue_lock, flags); |
| 2303 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2304 | if (!cic) |
| 2305 | goto queue_fail; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2306 | |
Vasily Tarasov | 91fac31 | 2007-04-25 12:29:51 +0200 | [diff] [blame] | 2307 | cfqq = cic_to_cfqq(cic, is_sync); |
| 2308 | if (!cfqq) { |
Jens Axboe | fd0928d | 2008-01-24 08:52:45 +0100 | [diff] [blame] | 2309 | cfqq = cfq_get_queue(cfqd, is_sync, cic->ioc, gfp_mask); |
Vasily Tarasov | 91fac31 | 2007-04-25 12:29:51 +0200 | [diff] [blame] | 2310 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2311 | if (!cfqq) |
| 2312 | goto queue_fail; |
| 2313 | |
Vasily Tarasov | 91fac31 | 2007-04-25 12:29:51 +0200 | [diff] [blame] | 2314 | cic_set_cfqq(cic, cfqq, is_sync); |
| 2315 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2316 | |
| 2317 | cfqq->allocated[rw]++; |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 2318 | cfq_clear_cfqq_must_alloc(cfqq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2319 | atomic_inc(&cfqq->ref); |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 2320 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2321 | spin_unlock_irqrestore(q->queue_lock, flags); |
| 2322 | |
Jens Axboe | 5e70537 | 2006-07-13 12:39:25 +0200 | [diff] [blame] | 2323 | rq->elevator_private = cic; |
| 2324 | rq->elevator_private2 = cfqq; |
| 2325 | return 0; |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 2326 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2327 | queue_fail: |
| 2328 | if (cic) |
| 2329 | put_io_context(cic->ioc); |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 2330 | |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 2331 | cfq_schedule_dispatch(cfqd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2332 | spin_unlock_irqrestore(q->queue_lock, flags); |
Jens Axboe | 7b67913 | 2008-05-30 12:23:07 +0200 | [diff] [blame] | 2333 | cfq_log(cfqd, "set_request fail"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2334 | return 1; |
| 2335 | } |
| 2336 | |
David Howells | 65f27f3 | 2006-11-22 14:55:48 +0000 | [diff] [blame] | 2337 | static void cfq_kick_queue(struct work_struct *work) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2338 | { |
David Howells | 65f27f3 | 2006-11-22 14:55:48 +0000 | [diff] [blame] | 2339 | struct cfq_data *cfqd = |
| 2340 | container_of(work, struct cfq_data, unplug_work); |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 2341 | struct request_queue *q = cfqd->queue; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2342 | |
Jens Axboe | 40bb54d | 2009-04-15 12:11:10 +0200 | [diff] [blame] | 2343 | spin_lock_irq(q->queue_lock); |
Tejun Heo | a7f5579 | 2009-04-23 11:05:17 +0900 | [diff] [blame] | 2344 | __blk_run_queue(cfqd->queue); |
Jens Axboe | 40bb54d | 2009-04-15 12:11:10 +0200 | [diff] [blame] | 2345 | spin_unlock_irq(q->queue_lock); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2346 | } |
| 2347 | |
| 2348 | /* |
| 2349 | * Timer running if the active_queue is currently idling inside its time slice |
| 2350 | */ |
| 2351 | static void cfq_idle_slice_timer(unsigned long data) |
| 2352 | { |
| 2353 | struct cfq_data *cfqd = (struct cfq_data *) data; |
| 2354 | struct cfq_queue *cfqq; |
| 2355 | unsigned long flags; |
Jens Axboe | 3c6bd2f | 2007-01-19 12:06:33 +1100 | [diff] [blame] | 2356 | int timed_out = 1; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2357 | |
Jens Axboe | 7b67913 | 2008-05-30 12:23:07 +0200 | [diff] [blame] | 2358 | cfq_log(cfqd, "idle timer fired"); |
| 2359 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2360 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); |
| 2361 | |
Jens Axboe | fe094d9 | 2008-01-31 13:08:54 +0100 | [diff] [blame] | 2362 | cfqq = cfqd->active_queue; |
| 2363 | if (cfqq) { |
Jens Axboe | 3c6bd2f | 2007-01-19 12:06:33 +1100 | [diff] [blame] | 2364 | timed_out = 0; |
| 2365 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2366 | /* |
Jens Axboe | b029195 | 2009-04-07 11:38:31 +0200 | [diff] [blame] | 2367 | * We saw a request before the queue expired, let it through |
| 2368 | */ |
| 2369 | if (cfq_cfqq_must_dispatch(cfqq)) |
| 2370 | goto out_kick; |
| 2371 | |
| 2372 | /* |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2373 | * expired |
| 2374 | */ |
Jens Axboe | 44f7c16 | 2007-01-19 11:51:58 +1100 | [diff] [blame] | 2375 | if (cfq_slice_used(cfqq)) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2376 | goto expire; |
| 2377 | |
| 2378 | /* |
| 2379 | * only expire and reinvoke request handler, if there are |
| 2380 | * other queues with pending requests |
| 2381 | */ |
Jens Axboe | caaa5f9 | 2006-06-16 11:23:00 +0200 | [diff] [blame] | 2382 | if (!cfqd->busy_queues) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2383 | goto out_cont; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2384 | |
| 2385 | /* |
| 2386 | * not expired and it has a request pending, let it dispatch |
| 2387 | */ |
Jens Axboe | 75e5098 | 2009-04-07 08:56:14 +0200 | [diff] [blame] | 2388 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2389 | goto out_kick; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2390 | } |
| 2391 | expire: |
Jens Axboe | 6084cdd | 2007-04-23 08:25:00 +0200 | [diff] [blame] | 2392 | cfq_slice_expired(cfqd, timed_out); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2393 | out_kick: |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 2394 | cfq_schedule_dispatch(cfqd); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2395 | out_cont: |
| 2396 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); |
| 2397 | } |
| 2398 | |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 2399 | static void cfq_shutdown_timer_wq(struct cfq_data *cfqd) |
| 2400 | { |
| 2401 | del_timer_sync(&cfqd->idle_slice_timer); |
Cheng Renquan | 64d01dc | 2008-12-03 12:41:39 +0100 | [diff] [blame] | 2402 | cancel_work_sync(&cfqd->unplug_work); |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 2403 | } |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2404 | |
Vasily Tarasov | c2dea2d | 2007-07-20 10:06:38 +0200 | [diff] [blame] | 2405 | static void cfq_put_async_queues(struct cfq_data *cfqd) |
| 2406 | { |
| 2407 | int i; |
| 2408 | |
| 2409 | for (i = 0; i < IOPRIO_BE_NR; i++) { |
| 2410 | if (cfqd->async_cfqq[0][i]) |
| 2411 | cfq_put_queue(cfqd->async_cfqq[0][i]); |
| 2412 | if (cfqd->async_cfqq[1][i]) |
| 2413 | cfq_put_queue(cfqd->async_cfqq[1][i]); |
Vasily Tarasov | c2dea2d | 2007-07-20 10:06:38 +0200 | [diff] [blame] | 2414 | } |
Oleg Nesterov | 2389d1e | 2007-11-05 08:58:05 +0100 | [diff] [blame] | 2415 | |
| 2416 | if (cfqd->async_idle_cfqq) |
| 2417 | cfq_put_queue(cfqd->async_idle_cfqq); |
Vasily Tarasov | c2dea2d | 2007-07-20 10:06:38 +0200 | [diff] [blame] | 2418 | } |
| 2419 | |
Jens Axboe | b374d18 | 2008-10-31 10:05:07 +0100 | [diff] [blame] | 2420 | static void cfq_exit_queue(struct elevator_queue *e) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2421 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2422 | struct cfq_data *cfqd = e->elevator_data; |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 2423 | struct request_queue *q = cfqd->queue; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2424 | |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 2425 | cfq_shutdown_timer_wq(cfqd); |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 2426 | |
Al Viro | d9ff418 | 2006-03-18 13:51:22 -0500 | [diff] [blame] | 2427 | spin_lock_irq(q->queue_lock); |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 2428 | |
Al Viro | d9ff418 | 2006-03-18 13:51:22 -0500 | [diff] [blame] | 2429 | if (cfqd->active_queue) |
Jens Axboe | 6084cdd | 2007-04-23 08:25:00 +0200 | [diff] [blame] | 2430 | __cfq_slice_expired(cfqd, cfqd->active_queue, 0); |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 2431 | |
| 2432 | while (!list_empty(&cfqd->cic_list)) { |
Al Viro | d9ff418 | 2006-03-18 13:51:22 -0500 | [diff] [blame] | 2433 | struct cfq_io_context *cic = list_entry(cfqd->cic_list.next, |
| 2434 | struct cfq_io_context, |
| 2435 | queue_list); |
Jens Axboe | 89850f7 | 2006-07-22 16:48:31 +0200 | [diff] [blame] | 2436 | |
| 2437 | __cfq_exit_single_io_context(cfqd, cic); |
Al Viro | d9ff418 | 2006-03-18 13:51:22 -0500 | [diff] [blame] | 2438 | } |
Jens Axboe | e2d74ac | 2006-03-28 08:59:01 +0200 | [diff] [blame] | 2439 | |
Vasily Tarasov | c2dea2d | 2007-07-20 10:06:38 +0200 | [diff] [blame] | 2440 | cfq_put_async_queues(cfqd); |
Jens Axboe | 15c31be | 2007-07-10 13:43:25 +0200 | [diff] [blame] | 2441 | |
Al Viro | d9ff418 | 2006-03-18 13:51:22 -0500 | [diff] [blame] | 2442 | spin_unlock_irq(q->queue_lock); |
Al Viro | a90d742 | 2006-03-18 12:05:37 -0500 | [diff] [blame] | 2443 | |
| 2444 | cfq_shutdown_timer_wq(cfqd); |
| 2445 | |
Al Viro | a90d742 | 2006-03-18 12:05:37 -0500 | [diff] [blame] | 2446 | kfree(cfqd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2447 | } |
| 2448 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 2449 | static void *cfq_init_queue(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2450 | { |
| 2451 | struct cfq_data *cfqd; |
Jens Axboe | 26a2ac0 | 2009-04-23 12:13:27 +0200 | [diff] [blame] | 2452 | int i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2453 | |
Christoph Lameter | 94f6030 | 2007-07-17 04:03:29 -0700 | [diff] [blame] | 2454 | cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL | __GFP_ZERO, q->node); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2455 | if (!cfqd) |
Jens Axboe | bc1c116 | 2006-06-08 08:49:06 +0200 | [diff] [blame] | 2456 | return NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2457 | |
Jens Axboe | cc09e29 | 2007-04-26 12:53:50 +0200 | [diff] [blame] | 2458 | cfqd->service_tree = CFQ_RB_ROOT; |
Jens Axboe | 26a2ac0 | 2009-04-23 12:13:27 +0200 | [diff] [blame] | 2459 | |
| 2460 | /* |
| 2461 | * Not strictly needed (since RB_ROOT just clears the node and we |
| 2462 | * zeroed cfqd on alloc), but better be safe in case someone decides |
| 2463 | * to add magic to the rb code |
| 2464 | */ |
| 2465 | for (i = 0; i < CFQ_PRIO_LISTS; i++) |
| 2466 | cfqd->prio_trees[i] = RB_ROOT; |
| 2467 | |
Al Viro | d9ff418 | 2006-03-18 13:51:22 -0500 | [diff] [blame] | 2468 | INIT_LIST_HEAD(&cfqd->cic_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2469 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2470 | cfqd->queue = q; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2471 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2472 | init_timer(&cfqd->idle_slice_timer); |
| 2473 | cfqd->idle_slice_timer.function = cfq_idle_slice_timer; |
| 2474 | cfqd->idle_slice_timer.data = (unsigned long) cfqd; |
| 2475 | |
David Howells | 65f27f3 | 2006-11-22 14:55:48 +0000 | [diff] [blame] | 2476 | INIT_WORK(&cfqd->unplug_work, cfq_kick_queue); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2477 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2478 | cfqd->cfq_quantum = cfq_quantum; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2479 | cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; |
| 2480 | cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2481 | cfqd->cfq_back_max = cfq_back_max; |
| 2482 | cfqd->cfq_back_penalty = cfq_back_penalty; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2483 | cfqd->cfq_slice[0] = cfq_slice_async; |
| 2484 | cfqd->cfq_slice[1] = cfq_slice_sync; |
| 2485 | cfqd->cfq_slice_async_rq = cfq_slice_async_rq; |
| 2486 | cfqd->cfq_slice_idle = cfq_slice_idle; |
Aaron Carroll | 45333d5 | 2008-08-26 15:52:36 +0200 | [diff] [blame] | 2487 | cfqd->hw_tag = 1; |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 2488 | |
Jens Axboe | bc1c116 | 2006-06-08 08:49:06 +0200 | [diff] [blame] | 2489 | return cfqd; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2490 | } |
| 2491 | |
| 2492 | static void cfq_slab_kill(void) |
| 2493 | { |
Jens Axboe | d6de8be | 2008-05-28 14:46:59 +0200 | [diff] [blame] | 2494 | /* |
| 2495 | * Caller already ensured that pending RCU callbacks are completed, |
| 2496 | * so we should have no busy allocations at this point. |
| 2497 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2498 | if (cfq_pool) |
| 2499 | kmem_cache_destroy(cfq_pool); |
| 2500 | if (cfq_ioc_pool) |
| 2501 | kmem_cache_destroy(cfq_ioc_pool); |
| 2502 | } |
| 2503 | |
| 2504 | static int __init cfq_slab_setup(void) |
| 2505 | { |
Christoph Lameter | 0a31bd5 | 2007-05-06 14:49:57 -0700 | [diff] [blame] | 2506 | cfq_pool = KMEM_CACHE(cfq_queue, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2507 | if (!cfq_pool) |
| 2508 | goto fail; |
| 2509 | |
Fabio Checconi | 34e6bbf | 2008-04-02 14:31:02 +0200 | [diff] [blame] | 2510 | cfq_ioc_pool = KMEM_CACHE(cfq_io_context, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2511 | if (!cfq_ioc_pool) |
| 2512 | goto fail; |
| 2513 | |
| 2514 | return 0; |
| 2515 | fail: |
| 2516 | cfq_slab_kill(); |
| 2517 | return -ENOMEM; |
| 2518 | } |
| 2519 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2520 | /* |
| 2521 | * sysfs parts below --> |
| 2522 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2523 | static ssize_t |
| 2524 | cfq_var_show(unsigned int var, char *page) |
| 2525 | { |
| 2526 | return sprintf(page, "%d\n", var); |
| 2527 | } |
| 2528 | |
| 2529 | static ssize_t |
| 2530 | cfq_var_store(unsigned int *var, const char *page, size_t count) |
| 2531 | { |
| 2532 | char *p = (char *) page; |
| 2533 | |
| 2534 | *var = simple_strtoul(p, &p, 10); |
| 2535 | return count; |
| 2536 | } |
| 2537 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2538 | #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ |
Jens Axboe | b374d18 | 2008-10-31 10:05:07 +0100 | [diff] [blame] | 2539 | static ssize_t __FUNC(struct elevator_queue *e, char *page) \ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2540 | { \ |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 2541 | struct cfq_data *cfqd = e->elevator_data; \ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2542 | unsigned int __data = __VAR; \ |
| 2543 | if (__CONV) \ |
| 2544 | __data = jiffies_to_msecs(__data); \ |
| 2545 | return cfq_var_show(__data, (page)); \ |
| 2546 | } |
| 2547 | SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2548 | SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1); |
| 2549 | 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] | 2550 | SHOW_FUNCTION(cfq_back_seek_max_show, cfqd->cfq_back_max, 0); |
| 2551 | SHOW_FUNCTION(cfq_back_seek_penalty_show, cfqd->cfq_back_penalty, 0); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2552 | SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1); |
| 2553 | SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1); |
| 2554 | SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1); |
| 2555 | 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] | 2556 | #undef SHOW_FUNCTION |
| 2557 | |
| 2558 | #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ |
Jens Axboe | b374d18 | 2008-10-31 10:05:07 +0100 | [diff] [blame] | 2559 | static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2560 | { \ |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 2561 | struct cfq_data *cfqd = e->elevator_data; \ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2562 | unsigned int __data; \ |
| 2563 | int ret = cfq_var_store(&__data, (page), count); \ |
| 2564 | if (__data < (MIN)) \ |
| 2565 | __data = (MIN); \ |
| 2566 | else if (__data > (MAX)) \ |
| 2567 | __data = (MAX); \ |
| 2568 | if (__CONV) \ |
| 2569 | *(__PTR) = msecs_to_jiffies(__data); \ |
| 2570 | else \ |
| 2571 | *(__PTR) = __data; \ |
| 2572 | return ret; \ |
| 2573 | } |
| 2574 | STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); |
Jens Axboe | fe094d9 | 2008-01-31 13:08:54 +0100 | [diff] [blame] | 2575 | STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, |
| 2576 | UINT_MAX, 1); |
| 2577 | STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, |
| 2578 | UINT_MAX, 1); |
Al Viro | e572ec7 | 2006-03-18 22:27:18 -0500 | [diff] [blame] | 2579 | STORE_FUNCTION(cfq_back_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); |
Jens Axboe | fe094d9 | 2008-01-31 13:08:54 +0100 | [diff] [blame] | 2580 | STORE_FUNCTION(cfq_back_seek_penalty_store, &cfqd->cfq_back_penalty, 1, |
| 2581 | UINT_MAX, 0); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2582 | STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1); |
| 2583 | STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1); |
| 2584 | STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1); |
Jens Axboe | fe094d9 | 2008-01-31 13:08:54 +0100 | [diff] [blame] | 2585 | STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, |
| 2586 | UINT_MAX, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2587 | #undef STORE_FUNCTION |
| 2588 | |
Al Viro | e572ec7 | 2006-03-18 22:27:18 -0500 | [diff] [blame] | 2589 | #define CFQ_ATTR(name) \ |
| 2590 | __ATTR(name, S_IRUGO|S_IWUSR, cfq_##name##_show, cfq_##name##_store) |
Jens Axboe | 3b18152 | 2005-06-27 10:56:24 +0200 | [diff] [blame] | 2591 | |
Al Viro | e572ec7 | 2006-03-18 22:27:18 -0500 | [diff] [blame] | 2592 | static struct elv_fs_entry cfq_attrs[] = { |
| 2593 | CFQ_ATTR(quantum), |
Al Viro | e572ec7 | 2006-03-18 22:27:18 -0500 | [diff] [blame] | 2594 | CFQ_ATTR(fifo_expire_sync), |
| 2595 | CFQ_ATTR(fifo_expire_async), |
| 2596 | CFQ_ATTR(back_seek_max), |
| 2597 | CFQ_ATTR(back_seek_penalty), |
| 2598 | CFQ_ATTR(slice_sync), |
| 2599 | CFQ_ATTR(slice_async), |
| 2600 | CFQ_ATTR(slice_async_rq), |
| 2601 | CFQ_ATTR(slice_idle), |
Al Viro | e572ec7 | 2006-03-18 22:27:18 -0500 | [diff] [blame] | 2602 | __ATTR_NULL |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2603 | }; |
| 2604 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2605 | static struct elevator_type iosched_cfq = { |
| 2606 | .ops = { |
| 2607 | .elevator_merge_fn = cfq_merge, |
| 2608 | .elevator_merged_fn = cfq_merged_request, |
| 2609 | .elevator_merge_req_fn = cfq_merged_requests, |
Jens Axboe | da77526 | 2006-12-20 11:04:12 +0100 | [diff] [blame] | 2610 | .elevator_allow_merge_fn = cfq_allow_merge, |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 2611 | .elevator_dispatch_fn = cfq_dispatch_requests, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2612 | .elevator_add_req_fn = cfq_insert_request, |
Jens Axboe | b4878f2 | 2005-10-20 16:42:29 +0200 | [diff] [blame] | 2613 | .elevator_activate_req_fn = cfq_activate_request, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2614 | .elevator_deactivate_req_fn = cfq_deactivate_request, |
| 2615 | .elevator_queue_empty_fn = cfq_queue_empty, |
| 2616 | .elevator_completed_req_fn = cfq_completed_request, |
Jens Axboe | 21183b0 | 2006-07-13 12:33:14 +0200 | [diff] [blame] | 2617 | .elevator_former_req_fn = elv_rb_former_request, |
| 2618 | .elevator_latter_req_fn = elv_rb_latter_request, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2619 | .elevator_set_req_fn = cfq_set_request, |
| 2620 | .elevator_put_req_fn = cfq_put_request, |
| 2621 | .elevator_may_queue_fn = cfq_may_queue, |
| 2622 | .elevator_init_fn = cfq_init_queue, |
| 2623 | .elevator_exit_fn = cfq_exit_queue, |
Jens Axboe | fc46379 | 2006-08-29 09:05:44 +0200 | [diff] [blame] | 2624 | .trim = cfq_free_io_context, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2625 | }, |
Al Viro | 3d1ab40 | 2006-03-18 18:35:43 -0500 | [diff] [blame] | 2626 | .elevator_attrs = cfq_attrs, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2627 | .elevator_name = "cfq", |
| 2628 | .elevator_owner = THIS_MODULE, |
| 2629 | }; |
| 2630 | |
| 2631 | static int __init cfq_init(void) |
| 2632 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2633 | /* |
| 2634 | * could be 0 on HZ < 1000 setups |
| 2635 | */ |
| 2636 | if (!cfq_slice_async) |
| 2637 | cfq_slice_async = 1; |
| 2638 | if (!cfq_slice_idle) |
| 2639 | cfq_slice_idle = 1; |
| 2640 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2641 | if (cfq_slab_setup()) |
| 2642 | return -ENOMEM; |
| 2643 | |
Adrian Bunk | 2fdd82b | 2007-12-12 18:51:56 +0100 | [diff] [blame] | 2644 | elv_register(&iosched_cfq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2645 | |
Adrian Bunk | 2fdd82b | 2007-12-12 18:51:56 +0100 | [diff] [blame] | 2646 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2647 | } |
| 2648 | |
| 2649 | static void __exit cfq_exit(void) |
| 2650 | { |
Peter Zijlstra | 6e9a473 | 2006-09-30 23:28:10 -0700 | [diff] [blame] | 2651 | DECLARE_COMPLETION_ONSTACK(all_gone); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2652 | elv_unregister(&iosched_cfq); |
Al Viro | 334e94d | 2006-03-18 15:05:53 -0500 | [diff] [blame] | 2653 | ioc_gone = &all_gone; |
OGAWA Hirofumi | fba8227 | 2006-04-18 09:44:06 +0200 | [diff] [blame] | 2654 | /* ioc_gone's update must be visible before reading ioc_count */ |
| 2655 | smp_wmb(); |
Jens Axboe | d6de8be | 2008-05-28 14:46:59 +0200 | [diff] [blame] | 2656 | |
| 2657 | /* |
| 2658 | * this also protects us from entering cfq_slab_kill() with |
| 2659 | * pending RCU callbacks |
| 2660 | */ |
Jens Axboe | 4050cf1 | 2006-07-19 05:07:12 +0200 | [diff] [blame] | 2661 | if (elv_ioc_count_read(ioc_count)) |
Jens Axboe | 9a11b4e | 2008-05-29 09:32:08 +0200 | [diff] [blame] | 2662 | wait_for_completion(&all_gone); |
Christoph Hellwig | 83521d3 | 2005-10-30 15:01:39 -0800 | [diff] [blame] | 2663 | cfq_slab_kill(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2664 | } |
| 2665 | |
| 2666 | module_init(cfq_init); |
| 2667 | module_exit(cfq_exit); |
| 2668 | |
| 2669 | MODULE_AUTHOR("Jens Axboe"); |
| 2670 | MODULE_LICENSE("GPL"); |
| 2671 | MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler"); |