Commit | Line | Data |
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1da177e4 | 1 | /* |
1da177e4 LT |
2 | * CFQ, or complete fairness queueing, disk scheduler. |
3 | * | |
4 | * Based on ideas from a previously unfinished io | |
5 | * scheduler (round robin per-process disk scheduling) and Andrea Arcangeli. | |
6 | * | |
0fe23479 | 7 | * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk> |
1da177e4 | 8 | */ |
1da177e4 | 9 | #include <linux/module.h> |
5a0e3ad6 | 10 | #include <linux/slab.h> |
1cc9be68 AV |
11 | #include <linux/blkdev.h> |
12 | #include <linux/elevator.h> | |
ad5ebd2f | 13 | #include <linux/jiffies.h> |
1da177e4 | 14 | #include <linux/rbtree.h> |
22e2c507 | 15 | #include <linux/ioprio.h> |
7b679138 | 16 | #include <linux/blktrace_api.h> |
25bc6b07 | 17 | #include "blk-cgroup.h" |
1da177e4 LT |
18 | |
19 | /* | |
20 | * tunables | |
21 | */ | |
fe094d98 | 22 | /* max queue in one round of service */ |
abc3c744 | 23 | static const int cfq_quantum = 8; |
64100099 | 24 | static const int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 }; |
fe094d98 JA |
25 | /* maximum backwards seek, in KiB */ |
26 | static const int cfq_back_max = 16 * 1024; | |
27 | /* penalty of a backwards seek */ | |
28 | static const int cfq_back_penalty = 2; | |
64100099 | 29 | static const int cfq_slice_sync = HZ / 10; |
3b18152c | 30 | static int cfq_slice_async = HZ / 25; |
64100099 | 31 | static const int cfq_slice_async_rq = 2; |
caaa5f9f | 32 | static int cfq_slice_idle = HZ / 125; |
5db5d642 CZ |
33 | static const int cfq_target_latency = HZ * 3/10; /* 300 ms */ |
34 | static const int cfq_hist_divisor = 4; | |
22e2c507 | 35 | |
d9e7620e | 36 | /* |
0871714e | 37 | * offset from end of service tree |
d9e7620e | 38 | */ |
0871714e | 39 | #define CFQ_IDLE_DELAY (HZ / 5) |
d9e7620e JA |
40 | |
41 | /* | |
42 | * below this threshold, we consider thinktime immediate | |
43 | */ | |
44 | #define CFQ_MIN_TT (2) | |
45 | ||
22e2c507 | 46 | #define CFQ_SLICE_SCALE (5) |
45333d5a | 47 | #define CFQ_HW_QUEUE_MIN (5) |
25bc6b07 | 48 | #define CFQ_SERVICE_SHIFT 12 |
22e2c507 | 49 | |
3dde36dd | 50 | #define CFQQ_SEEK_THR (sector_t)(8 * 100) |
e9ce335d | 51 | #define CFQQ_CLOSE_THR (sector_t)(8 * 1024) |
41647e7a | 52 | #define CFQQ_SECT_THR_NONROT (sector_t)(2 * 32) |
3dde36dd | 53 | #define CFQQ_SEEKY(cfqq) (hweight32(cfqq->seek_history) > 32/8) |
ae54abed | 54 | |
fe094d98 JA |
55 | #define RQ_CIC(rq) \ |
56 | ((struct cfq_io_context *) (rq)->elevator_private) | |
7b679138 | 57 | #define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elevator_private2) |
1da177e4 | 58 | |
e18b890b CL |
59 | static struct kmem_cache *cfq_pool; |
60 | static struct kmem_cache *cfq_ioc_pool; | |
1da177e4 | 61 | |
245b2e70 | 62 | static DEFINE_PER_CPU(unsigned long, cfq_ioc_count); |
334e94de | 63 | static struct completion *ioc_gone; |
9a11b4ed | 64 | static DEFINE_SPINLOCK(ioc_gone_lock); |
334e94de | 65 | |
22e2c507 JA |
66 | #define CFQ_PRIO_LISTS IOPRIO_BE_NR |
67 | #define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE) | |
22e2c507 JA |
68 | #define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT) |
69 | ||
206dc69b | 70 | #define sample_valid(samples) ((samples) > 80) |
1fa8f6d6 | 71 | #define rb_entry_cfqg(node) rb_entry((node), struct cfq_group, rb_node) |
206dc69b | 72 | |
cc09e299 JA |
73 | /* |
74 | * Most of our rbtree usage is for sorting with min extraction, so | |
75 | * if we cache the leftmost node we don't have to walk down the tree | |
76 | * to find it. Idea borrowed from Ingo Molnars CFS scheduler. We should | |
77 | * move this into the elevator for the rq sorting as well. | |
78 | */ | |
79 | struct cfq_rb_root { | |
80 | struct rb_root rb; | |
81 | struct rb_node *left; | |
aa6f6a3d | 82 | unsigned count; |
73e9ffdd | 83 | unsigned total_weight; |
1fa8f6d6 | 84 | u64 min_vdisktime; |
25bc6b07 | 85 | struct rb_node *active; |
cc09e299 | 86 | }; |
73e9ffdd RK |
87 | #define CFQ_RB_ROOT (struct cfq_rb_root) { .rb = RB_ROOT, .left = NULL, \ |
88 | .count = 0, .min_vdisktime = 0, } | |
cc09e299 | 89 | |
6118b70b JA |
90 | /* |
91 | * Per process-grouping structure | |
92 | */ | |
93 | struct cfq_queue { | |
94 | /* reference count */ | |
95 | atomic_t ref; | |
96 | /* various state flags, see below */ | |
97 | unsigned int flags; | |
98 | /* parent cfq_data */ | |
99 | struct cfq_data *cfqd; | |
100 | /* service_tree member */ | |
101 | struct rb_node rb_node; | |
102 | /* service_tree key */ | |
103 | unsigned long rb_key; | |
104 | /* prio tree member */ | |
105 | struct rb_node p_node; | |
106 | /* prio tree root we belong to, if any */ | |
107 | struct rb_root *p_root; | |
108 | /* sorted list of pending requests */ | |
109 | struct rb_root sort_list; | |
110 | /* if fifo isn't expired, next request to serve */ | |
111 | struct request *next_rq; | |
112 | /* requests queued in sort_list */ | |
113 | int queued[2]; | |
114 | /* currently allocated requests */ | |
115 | int allocated[2]; | |
116 | /* fifo list of requests in sort_list */ | |
117 | struct list_head fifo; | |
118 | ||
dae739eb VG |
119 | /* time when queue got scheduled in to dispatch first request. */ |
120 | unsigned long dispatch_start; | |
f75edf2d | 121 | unsigned int allocated_slice; |
c4081ba5 | 122 | unsigned int slice_dispatch; |
dae739eb VG |
123 | /* time when first request from queue completed and slice started. */ |
124 | unsigned long slice_start; | |
6118b70b JA |
125 | unsigned long slice_end; |
126 | long slice_resid; | |
6118b70b JA |
127 | |
128 | /* pending metadata requests */ | |
129 | int meta_pending; | |
130 | /* number of requests that are on the dispatch list or inside driver */ | |
131 | int dispatched; | |
132 | ||
133 | /* io prio of this group */ | |
134 | unsigned short ioprio, org_ioprio; | |
135 | unsigned short ioprio_class, org_ioprio_class; | |
136 | ||
c4081ba5 RK |
137 | pid_t pid; |
138 | ||
3dde36dd | 139 | u32 seek_history; |
b2c18e1e JM |
140 | sector_t last_request_pos; |
141 | ||
aa6f6a3d | 142 | struct cfq_rb_root *service_tree; |
df5fe3e8 | 143 | struct cfq_queue *new_cfqq; |
cdb16e8f | 144 | struct cfq_group *cfqg; |
ae30c286 | 145 | struct cfq_group *orig_cfqg; |
22084190 VG |
146 | /* Sectors dispatched in current dispatch round */ |
147 | unsigned long nr_sectors; | |
6118b70b JA |
148 | }; |
149 | ||
c0324a02 | 150 | /* |
718eee05 | 151 | * First index in the service_trees. |
c0324a02 CZ |
152 | * IDLE is handled separately, so it has negative index |
153 | */ | |
154 | enum wl_prio_t { | |
c0324a02 | 155 | BE_WORKLOAD = 0, |
615f0259 VG |
156 | RT_WORKLOAD = 1, |
157 | IDLE_WORKLOAD = 2, | |
c0324a02 CZ |
158 | }; |
159 | ||
718eee05 CZ |
160 | /* |
161 | * Second index in the service_trees. | |
162 | */ | |
163 | enum wl_type_t { | |
164 | ASYNC_WORKLOAD = 0, | |
165 | SYNC_NOIDLE_WORKLOAD = 1, | |
166 | SYNC_WORKLOAD = 2 | |
167 | }; | |
168 | ||
cdb16e8f VG |
169 | /* This is per cgroup per device grouping structure */ |
170 | struct cfq_group { | |
1fa8f6d6 VG |
171 | /* group service_tree member */ |
172 | struct rb_node rb_node; | |
173 | ||
174 | /* group service_tree key */ | |
175 | u64 vdisktime; | |
25bc6b07 | 176 | unsigned int weight; |
1fa8f6d6 VG |
177 | bool on_st; |
178 | ||
179 | /* number of cfqq currently on this group */ | |
180 | int nr_cfqq; | |
181 | ||
58ff82f3 VG |
182 | /* Per group busy queus average. Useful for workload slice calc. */ |
183 | unsigned int busy_queues_avg[2]; | |
cdb16e8f VG |
184 | /* |
185 | * rr lists of queues with requests, onle rr for each priority class. | |
186 | * Counts are embedded in the cfq_rb_root | |
187 | */ | |
188 | struct cfq_rb_root service_trees[2][3]; | |
189 | struct cfq_rb_root service_tree_idle; | |
dae739eb VG |
190 | |
191 | unsigned long saved_workload_slice; | |
192 | enum wl_type_t saved_workload; | |
193 | enum wl_prio_t saved_serving_prio; | |
25fb5169 VG |
194 | struct blkio_group blkg; |
195 | #ifdef CONFIG_CFQ_GROUP_IOSCHED | |
196 | struct hlist_node cfqd_node; | |
b1c35769 | 197 | atomic_t ref; |
25fb5169 | 198 | #endif |
cdb16e8f | 199 | }; |
718eee05 | 200 | |
22e2c507 JA |
201 | /* |
202 | * Per block device queue structure | |
203 | */ | |
1da177e4 | 204 | struct cfq_data { |
165125e1 | 205 | struct request_queue *queue; |
1fa8f6d6 VG |
206 | /* Root service tree for cfq_groups */ |
207 | struct cfq_rb_root grp_service_tree; | |
cdb16e8f | 208 | struct cfq_group root_group; |
22e2c507 | 209 | |
c0324a02 CZ |
210 | /* |
211 | * The priority currently being served | |
22e2c507 | 212 | */ |
c0324a02 | 213 | enum wl_prio_t serving_prio; |
718eee05 CZ |
214 | enum wl_type_t serving_type; |
215 | unsigned long workload_expires; | |
cdb16e8f | 216 | struct cfq_group *serving_group; |
8e550632 | 217 | bool noidle_tree_requires_idle; |
a36e71f9 JA |
218 | |
219 | /* | |
220 | * Each priority tree is sorted by next_request position. These | |
221 | * trees are used when determining if two or more queues are | |
222 | * interleaving requests (see cfq_close_cooperator). | |
223 | */ | |
224 | struct rb_root prio_trees[CFQ_PRIO_LISTS]; | |
225 | ||
22e2c507 JA |
226 | unsigned int busy_queues; |
227 | ||
53c583d2 CZ |
228 | int rq_in_driver; |
229 | int rq_in_flight[2]; | |
45333d5a AC |
230 | |
231 | /* | |
232 | * queue-depth detection | |
233 | */ | |
234 | int rq_queued; | |
25776e35 | 235 | int hw_tag; |
e459dd08 CZ |
236 | /* |
237 | * hw_tag can be | |
238 | * -1 => indeterminate, (cfq will behave as if NCQ is present, to allow better detection) | |
239 | * 1 => NCQ is present (hw_tag_est_depth is the estimated max depth) | |
240 | * 0 => no NCQ | |
241 | */ | |
242 | int hw_tag_est_depth; | |
243 | unsigned int hw_tag_samples; | |
1da177e4 | 244 | |
22e2c507 JA |
245 | /* |
246 | * idle window management | |
247 | */ | |
248 | struct timer_list idle_slice_timer; | |
23e018a1 | 249 | struct work_struct unplug_work; |
1da177e4 | 250 | |
22e2c507 JA |
251 | struct cfq_queue *active_queue; |
252 | struct cfq_io_context *active_cic; | |
22e2c507 | 253 | |
c2dea2d1 VT |
254 | /* |
255 | * async queue for each priority case | |
256 | */ | |
257 | struct cfq_queue *async_cfqq[2][IOPRIO_BE_NR]; | |
258 | struct cfq_queue *async_idle_cfqq; | |
15c31be4 | 259 | |
6d048f53 | 260 | sector_t last_position; |
1da177e4 | 261 | |
1da177e4 LT |
262 | /* |
263 | * tunables, see top of file | |
264 | */ | |
265 | unsigned int cfq_quantum; | |
22e2c507 | 266 | unsigned int cfq_fifo_expire[2]; |
1da177e4 LT |
267 | unsigned int cfq_back_penalty; |
268 | unsigned int cfq_back_max; | |
22e2c507 JA |
269 | unsigned int cfq_slice[2]; |
270 | unsigned int cfq_slice_async_rq; | |
271 | unsigned int cfq_slice_idle; | |
963b72fc | 272 | unsigned int cfq_latency; |
ae30c286 | 273 | unsigned int cfq_group_isolation; |
d9ff4187 AV |
274 | |
275 | struct list_head cic_list; | |
1da177e4 | 276 | |
6118b70b JA |
277 | /* |
278 | * Fallback dummy cfqq for extreme OOM conditions | |
279 | */ | |
280 | struct cfq_queue oom_cfqq; | |
365722bb | 281 | |
573412b2 | 282 | unsigned long last_delayed_sync; |
25fb5169 VG |
283 | |
284 | /* List of cfq groups being managed on this device*/ | |
285 | struct hlist_head cfqg_list; | |
bb729bc9 | 286 | struct rcu_head rcu; |
1da177e4 LT |
287 | }; |
288 | ||
25fb5169 VG |
289 | static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd); |
290 | ||
cdb16e8f VG |
291 | static struct cfq_rb_root *service_tree_for(struct cfq_group *cfqg, |
292 | enum wl_prio_t prio, | |
65b32a57 | 293 | enum wl_type_t type) |
c0324a02 | 294 | { |
1fa8f6d6 VG |
295 | if (!cfqg) |
296 | return NULL; | |
297 | ||
c0324a02 | 298 | if (prio == IDLE_WORKLOAD) |
cdb16e8f | 299 | return &cfqg->service_tree_idle; |
c0324a02 | 300 | |
cdb16e8f | 301 | return &cfqg->service_trees[prio][type]; |
c0324a02 CZ |
302 | } |
303 | ||
3b18152c | 304 | enum cfqq_state_flags { |
b0b8d749 JA |
305 | CFQ_CFQQ_FLAG_on_rr = 0, /* on round-robin busy list */ |
306 | CFQ_CFQQ_FLAG_wait_request, /* waiting for a request */ | |
b029195d | 307 | CFQ_CFQQ_FLAG_must_dispatch, /* must be allowed a dispatch */ |
b0b8d749 | 308 | CFQ_CFQQ_FLAG_must_alloc_slice, /* per-slice must_alloc flag */ |
b0b8d749 JA |
309 | CFQ_CFQQ_FLAG_fifo_expire, /* FIFO checked in this slice */ |
310 | CFQ_CFQQ_FLAG_idle_window, /* slice idling enabled */ | |
311 | CFQ_CFQQ_FLAG_prio_changed, /* task priority has changed */ | |
44f7c160 | 312 | CFQ_CFQQ_FLAG_slice_new, /* no requests dispatched in slice */ |
91fac317 | 313 | CFQ_CFQQ_FLAG_sync, /* synchronous queue */ |
b3b6d040 | 314 | CFQ_CFQQ_FLAG_coop, /* cfqq is shared */ |
ae54abed | 315 | CFQ_CFQQ_FLAG_split_coop, /* shared cfqq will be splitted */ |
76280aff | 316 | CFQ_CFQQ_FLAG_deep, /* sync cfqq experienced large depth */ |
f75edf2d | 317 | CFQ_CFQQ_FLAG_wait_busy, /* Waiting for next request */ |
3b18152c JA |
318 | }; |
319 | ||
320 | #define CFQ_CFQQ_FNS(name) \ | |
321 | static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \ | |
322 | { \ | |
fe094d98 | 323 | (cfqq)->flags |= (1 << CFQ_CFQQ_FLAG_##name); \ |
3b18152c JA |
324 | } \ |
325 | static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \ | |
326 | { \ | |
fe094d98 | 327 | (cfqq)->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \ |
3b18152c JA |
328 | } \ |
329 | static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \ | |
330 | { \ | |
fe094d98 | 331 | return ((cfqq)->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \ |
3b18152c JA |
332 | } |
333 | ||
334 | CFQ_CFQQ_FNS(on_rr); | |
335 | CFQ_CFQQ_FNS(wait_request); | |
b029195d | 336 | CFQ_CFQQ_FNS(must_dispatch); |
3b18152c | 337 | CFQ_CFQQ_FNS(must_alloc_slice); |
3b18152c JA |
338 | CFQ_CFQQ_FNS(fifo_expire); |
339 | CFQ_CFQQ_FNS(idle_window); | |
340 | CFQ_CFQQ_FNS(prio_changed); | |
44f7c160 | 341 | CFQ_CFQQ_FNS(slice_new); |
91fac317 | 342 | CFQ_CFQQ_FNS(sync); |
a36e71f9 | 343 | CFQ_CFQQ_FNS(coop); |
ae54abed | 344 | CFQ_CFQQ_FNS(split_coop); |
76280aff | 345 | CFQ_CFQQ_FNS(deep); |
f75edf2d | 346 | CFQ_CFQQ_FNS(wait_busy); |
3b18152c JA |
347 | #undef CFQ_CFQQ_FNS |
348 | ||
2868ef7b VG |
349 | #ifdef CONFIG_DEBUG_CFQ_IOSCHED |
350 | #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \ | |
351 | blk_add_trace_msg((cfqd)->queue, "cfq%d%c %s " fmt, (cfqq)->pid, \ | |
352 | cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \ | |
353 | blkg_path(&(cfqq)->cfqg->blkg), ##args); | |
354 | ||
355 | #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) \ | |
356 | blk_add_trace_msg((cfqd)->queue, "%s " fmt, \ | |
357 | blkg_path(&(cfqg)->blkg), ##args); \ | |
358 | ||
359 | #else | |
7b679138 JA |
360 | #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \ |
361 | blk_add_trace_msg((cfqd)->queue, "cfq%d " fmt, (cfqq)->pid, ##args) | |
2868ef7b VG |
362 | #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) do {} while (0); |
363 | #endif | |
7b679138 JA |
364 | #define cfq_log(cfqd, fmt, args...) \ |
365 | blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args) | |
366 | ||
615f0259 VG |
367 | /* Traverses through cfq group service trees */ |
368 | #define for_each_cfqg_st(cfqg, i, j, st) \ | |
369 | for (i = 0; i <= IDLE_WORKLOAD; i++) \ | |
370 | for (j = 0, st = i < IDLE_WORKLOAD ? &cfqg->service_trees[i][j]\ | |
371 | : &cfqg->service_tree_idle; \ | |
372 | (i < IDLE_WORKLOAD && j <= SYNC_WORKLOAD) || \ | |
373 | (i == IDLE_WORKLOAD && j == 0); \ | |
374 | j++, st = i < IDLE_WORKLOAD ? \ | |
375 | &cfqg->service_trees[i][j]: NULL) \ | |
376 | ||
377 | ||
c0324a02 CZ |
378 | static inline enum wl_prio_t cfqq_prio(struct cfq_queue *cfqq) |
379 | { | |
380 | if (cfq_class_idle(cfqq)) | |
381 | return IDLE_WORKLOAD; | |
382 | if (cfq_class_rt(cfqq)) | |
383 | return RT_WORKLOAD; | |
384 | return BE_WORKLOAD; | |
385 | } | |
386 | ||
718eee05 CZ |
387 | |
388 | static enum wl_type_t cfqq_type(struct cfq_queue *cfqq) | |
389 | { | |
390 | if (!cfq_cfqq_sync(cfqq)) | |
391 | return ASYNC_WORKLOAD; | |
392 | if (!cfq_cfqq_idle_window(cfqq)) | |
393 | return SYNC_NOIDLE_WORKLOAD; | |
394 | return SYNC_WORKLOAD; | |
395 | } | |
396 | ||
58ff82f3 VG |
397 | static inline int cfq_group_busy_queues_wl(enum wl_prio_t wl, |
398 | struct cfq_data *cfqd, | |
399 | struct cfq_group *cfqg) | |
c0324a02 CZ |
400 | { |
401 | if (wl == IDLE_WORKLOAD) | |
cdb16e8f | 402 | return cfqg->service_tree_idle.count; |
c0324a02 | 403 | |
cdb16e8f VG |
404 | return cfqg->service_trees[wl][ASYNC_WORKLOAD].count |
405 | + cfqg->service_trees[wl][SYNC_NOIDLE_WORKLOAD].count | |
406 | + cfqg->service_trees[wl][SYNC_WORKLOAD].count; | |
c0324a02 CZ |
407 | } |
408 | ||
f26bd1f0 VG |
409 | static inline int cfqg_busy_async_queues(struct cfq_data *cfqd, |
410 | struct cfq_group *cfqg) | |
411 | { | |
412 | return cfqg->service_trees[RT_WORKLOAD][ASYNC_WORKLOAD].count | |
413 | + cfqg->service_trees[BE_WORKLOAD][ASYNC_WORKLOAD].count; | |
414 | } | |
415 | ||
165125e1 | 416 | static void cfq_dispatch_insert(struct request_queue *, struct request *); |
a6151c3a | 417 | static struct cfq_queue *cfq_get_queue(struct cfq_data *, bool, |
fd0928df | 418 | struct io_context *, gfp_t); |
4ac845a2 | 419 | static struct cfq_io_context *cfq_cic_lookup(struct cfq_data *, |
91fac317 VT |
420 | struct io_context *); |
421 | ||
422 | static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_context *cic, | |
a6151c3a | 423 | bool is_sync) |
91fac317 | 424 | { |
a6151c3a | 425 | return cic->cfqq[is_sync]; |
91fac317 VT |
426 | } |
427 | ||
428 | static inline void cic_set_cfqq(struct cfq_io_context *cic, | |
a6151c3a | 429 | struct cfq_queue *cfqq, bool is_sync) |
91fac317 | 430 | { |
a6151c3a | 431 | cic->cfqq[is_sync] = cfqq; |
91fac317 VT |
432 | } |
433 | ||
434 | /* | |
435 | * We regard a request as SYNC, if it's either a read or has the SYNC bit | |
436 | * set (in which case it could also be direct WRITE). | |
437 | */ | |
a6151c3a | 438 | static inline bool cfq_bio_sync(struct bio *bio) |
91fac317 | 439 | { |
a6151c3a | 440 | return bio_data_dir(bio) == READ || bio_rw_flagged(bio, BIO_RW_SYNCIO); |
91fac317 | 441 | } |
1da177e4 | 442 | |
99f95e52 AM |
443 | /* |
444 | * scheduler run of queue, if there are requests pending and no one in the | |
445 | * driver that will restart queueing | |
446 | */ | |
23e018a1 | 447 | static inline void cfq_schedule_dispatch(struct cfq_data *cfqd) |
99f95e52 | 448 | { |
7b679138 JA |
449 | if (cfqd->busy_queues) { |
450 | cfq_log(cfqd, "schedule dispatch"); | |
23e018a1 | 451 | kblockd_schedule_work(cfqd->queue, &cfqd->unplug_work); |
7b679138 | 452 | } |
99f95e52 AM |
453 | } |
454 | ||
165125e1 | 455 | static int cfq_queue_empty(struct request_queue *q) |
99f95e52 AM |
456 | { |
457 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
458 | ||
f04a6424 | 459 | return !cfqd->rq_queued; |
99f95e52 AM |
460 | } |
461 | ||
44f7c160 JA |
462 | /* |
463 | * Scale schedule slice based on io priority. Use the sync time slice only | |
464 | * if a queue is marked sync and has sync io queued. A sync queue with async | |
465 | * io only, should not get full sync slice length. | |
466 | */ | |
a6151c3a | 467 | static inline int cfq_prio_slice(struct cfq_data *cfqd, bool sync, |
d9e7620e | 468 | unsigned short prio) |
44f7c160 | 469 | { |
d9e7620e | 470 | const int base_slice = cfqd->cfq_slice[sync]; |
44f7c160 | 471 | |
d9e7620e JA |
472 | WARN_ON(prio >= IOPRIO_BE_NR); |
473 | ||
474 | return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - prio)); | |
475 | } | |
44f7c160 | 476 | |
d9e7620e JA |
477 | static inline int |
478 | cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
479 | { | |
480 | return cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio); | |
44f7c160 JA |
481 | } |
482 | ||
25bc6b07 VG |
483 | static inline u64 cfq_scale_slice(unsigned long delta, struct cfq_group *cfqg) |
484 | { | |
485 | u64 d = delta << CFQ_SERVICE_SHIFT; | |
486 | ||
487 | d = d * BLKIO_WEIGHT_DEFAULT; | |
488 | do_div(d, cfqg->weight); | |
489 | return d; | |
490 | } | |
491 | ||
492 | static inline u64 max_vdisktime(u64 min_vdisktime, u64 vdisktime) | |
493 | { | |
494 | s64 delta = (s64)(vdisktime - min_vdisktime); | |
495 | if (delta > 0) | |
496 | min_vdisktime = vdisktime; | |
497 | ||
498 | return min_vdisktime; | |
499 | } | |
500 | ||
501 | static inline u64 min_vdisktime(u64 min_vdisktime, u64 vdisktime) | |
502 | { | |
503 | s64 delta = (s64)(vdisktime - min_vdisktime); | |
504 | if (delta < 0) | |
505 | min_vdisktime = vdisktime; | |
506 | ||
507 | return min_vdisktime; | |
508 | } | |
509 | ||
510 | static void update_min_vdisktime(struct cfq_rb_root *st) | |
511 | { | |
512 | u64 vdisktime = st->min_vdisktime; | |
513 | struct cfq_group *cfqg; | |
514 | ||
515 | if (st->active) { | |
516 | cfqg = rb_entry_cfqg(st->active); | |
517 | vdisktime = cfqg->vdisktime; | |
518 | } | |
519 | ||
520 | if (st->left) { | |
521 | cfqg = rb_entry_cfqg(st->left); | |
522 | vdisktime = min_vdisktime(vdisktime, cfqg->vdisktime); | |
523 | } | |
524 | ||
525 | st->min_vdisktime = max_vdisktime(st->min_vdisktime, vdisktime); | |
526 | } | |
527 | ||
5db5d642 CZ |
528 | /* |
529 | * get averaged number of queues of RT/BE priority. | |
530 | * average is updated, with a formula that gives more weight to higher numbers, | |
531 | * to quickly follows sudden increases and decrease slowly | |
532 | */ | |
533 | ||
58ff82f3 VG |
534 | static inline unsigned cfq_group_get_avg_queues(struct cfq_data *cfqd, |
535 | struct cfq_group *cfqg, bool rt) | |
5869619c | 536 | { |
5db5d642 CZ |
537 | unsigned min_q, max_q; |
538 | unsigned mult = cfq_hist_divisor - 1; | |
539 | unsigned round = cfq_hist_divisor / 2; | |
58ff82f3 | 540 | unsigned busy = cfq_group_busy_queues_wl(rt, cfqd, cfqg); |
5db5d642 | 541 | |
58ff82f3 VG |
542 | min_q = min(cfqg->busy_queues_avg[rt], busy); |
543 | max_q = max(cfqg->busy_queues_avg[rt], busy); | |
544 | cfqg->busy_queues_avg[rt] = (mult * max_q + min_q + round) / | |
5db5d642 | 545 | cfq_hist_divisor; |
58ff82f3 VG |
546 | return cfqg->busy_queues_avg[rt]; |
547 | } | |
548 | ||
549 | static inline unsigned | |
550 | cfq_group_slice(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
551 | { | |
552 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
553 | ||
554 | return cfq_target_latency * cfqg->weight / st->total_weight; | |
5db5d642 CZ |
555 | } |
556 | ||
44f7c160 JA |
557 | static inline void |
558 | cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
559 | { | |
5db5d642 CZ |
560 | unsigned slice = cfq_prio_to_slice(cfqd, cfqq); |
561 | if (cfqd->cfq_latency) { | |
58ff82f3 VG |
562 | /* |
563 | * interested queues (we consider only the ones with the same | |
564 | * priority class in the cfq group) | |
565 | */ | |
566 | unsigned iq = cfq_group_get_avg_queues(cfqd, cfqq->cfqg, | |
567 | cfq_class_rt(cfqq)); | |
5db5d642 CZ |
568 | unsigned sync_slice = cfqd->cfq_slice[1]; |
569 | unsigned expect_latency = sync_slice * iq; | |
58ff82f3 VG |
570 | unsigned group_slice = cfq_group_slice(cfqd, cfqq->cfqg); |
571 | ||
572 | if (expect_latency > group_slice) { | |
5db5d642 CZ |
573 | unsigned base_low_slice = 2 * cfqd->cfq_slice_idle; |
574 | /* scale low_slice according to IO priority | |
575 | * and sync vs async */ | |
576 | unsigned low_slice = | |
577 | min(slice, base_low_slice * slice / sync_slice); | |
578 | /* the adapted slice value is scaled to fit all iqs | |
579 | * into the target latency */ | |
58ff82f3 | 580 | slice = max(slice * group_slice / expect_latency, |
5db5d642 CZ |
581 | low_slice); |
582 | } | |
583 | } | |
dae739eb | 584 | cfqq->slice_start = jiffies; |
5db5d642 | 585 | cfqq->slice_end = jiffies + slice; |
f75edf2d | 586 | cfqq->allocated_slice = slice; |
7b679138 | 587 | cfq_log_cfqq(cfqd, cfqq, "set_slice=%lu", cfqq->slice_end - jiffies); |
44f7c160 JA |
588 | } |
589 | ||
590 | /* | |
591 | * We need to wrap this check in cfq_cfqq_slice_new(), since ->slice_end | |
592 | * isn't valid until the first request from the dispatch is activated | |
593 | * and the slice time set. | |
594 | */ | |
a6151c3a | 595 | static inline bool cfq_slice_used(struct cfq_queue *cfqq) |
44f7c160 JA |
596 | { |
597 | if (cfq_cfqq_slice_new(cfqq)) | |
598 | return 0; | |
599 | if (time_before(jiffies, cfqq->slice_end)) | |
600 | return 0; | |
601 | ||
602 | return 1; | |
603 | } | |
604 | ||
1da177e4 | 605 | /* |
5e705374 | 606 | * Lifted from AS - choose which of rq1 and rq2 that is best served now. |
1da177e4 | 607 | * We choose the request that is closest to the head right now. Distance |
e8a99053 | 608 | * behind the head is penalized and only allowed to a certain extent. |
1da177e4 | 609 | */ |
5e705374 | 610 | static struct request * |
cf7c25cf | 611 | cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2, sector_t last) |
1da177e4 | 612 | { |
cf7c25cf | 613 | sector_t s1, s2, d1 = 0, d2 = 0; |
1da177e4 | 614 | unsigned long back_max; |
e8a99053 AM |
615 | #define CFQ_RQ1_WRAP 0x01 /* request 1 wraps */ |
616 | #define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */ | |
617 | unsigned wrap = 0; /* bit mask: requests behind the disk head? */ | |
1da177e4 | 618 | |
5e705374 JA |
619 | if (rq1 == NULL || rq1 == rq2) |
620 | return rq2; | |
621 | if (rq2 == NULL) | |
622 | return rq1; | |
9c2c38a1 | 623 | |
5e705374 JA |
624 | if (rq_is_sync(rq1) && !rq_is_sync(rq2)) |
625 | return rq1; | |
626 | else if (rq_is_sync(rq2) && !rq_is_sync(rq1)) | |
627 | return rq2; | |
374f84ac JA |
628 | if (rq_is_meta(rq1) && !rq_is_meta(rq2)) |
629 | return rq1; | |
630 | else if (rq_is_meta(rq2) && !rq_is_meta(rq1)) | |
631 | return rq2; | |
1da177e4 | 632 | |
83096ebf TH |
633 | s1 = blk_rq_pos(rq1); |
634 | s2 = blk_rq_pos(rq2); | |
1da177e4 | 635 | |
1da177e4 LT |
636 | /* |
637 | * by definition, 1KiB is 2 sectors | |
638 | */ | |
639 | back_max = cfqd->cfq_back_max * 2; | |
640 | ||
641 | /* | |
642 | * Strict one way elevator _except_ in the case where we allow | |
643 | * short backward seeks which are biased as twice the cost of a | |
644 | * similar forward seek. | |
645 | */ | |
646 | if (s1 >= last) | |
647 | d1 = s1 - last; | |
648 | else if (s1 + back_max >= last) | |
649 | d1 = (last - s1) * cfqd->cfq_back_penalty; | |
650 | else | |
e8a99053 | 651 | wrap |= CFQ_RQ1_WRAP; |
1da177e4 LT |
652 | |
653 | if (s2 >= last) | |
654 | d2 = s2 - last; | |
655 | else if (s2 + back_max >= last) | |
656 | d2 = (last - s2) * cfqd->cfq_back_penalty; | |
657 | else | |
e8a99053 | 658 | wrap |= CFQ_RQ2_WRAP; |
1da177e4 LT |
659 | |
660 | /* Found required data */ | |
e8a99053 AM |
661 | |
662 | /* | |
663 | * By doing switch() on the bit mask "wrap" we avoid having to | |
664 | * check two variables for all permutations: --> faster! | |
665 | */ | |
666 | switch (wrap) { | |
5e705374 | 667 | case 0: /* common case for CFQ: rq1 and rq2 not wrapped */ |
e8a99053 | 668 | if (d1 < d2) |
5e705374 | 669 | return rq1; |
e8a99053 | 670 | else if (d2 < d1) |
5e705374 | 671 | return rq2; |
e8a99053 AM |
672 | else { |
673 | if (s1 >= s2) | |
5e705374 | 674 | return rq1; |
e8a99053 | 675 | else |
5e705374 | 676 | return rq2; |
e8a99053 | 677 | } |
1da177e4 | 678 | |
e8a99053 | 679 | case CFQ_RQ2_WRAP: |
5e705374 | 680 | return rq1; |
e8a99053 | 681 | case CFQ_RQ1_WRAP: |
5e705374 JA |
682 | return rq2; |
683 | case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both rqs wrapped */ | |
e8a99053 AM |
684 | default: |
685 | /* | |
686 | * Since both rqs are wrapped, | |
687 | * start with the one that's further behind head | |
688 | * (--> only *one* back seek required), | |
689 | * since back seek takes more time than forward. | |
690 | */ | |
691 | if (s1 <= s2) | |
5e705374 | 692 | return rq1; |
1da177e4 | 693 | else |
5e705374 | 694 | return rq2; |
1da177e4 LT |
695 | } |
696 | } | |
697 | ||
498d3aa2 JA |
698 | /* |
699 | * The below is leftmost cache rbtree addon | |
700 | */ | |
0871714e | 701 | static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root) |
cc09e299 | 702 | { |
615f0259 VG |
703 | /* Service tree is empty */ |
704 | if (!root->count) | |
705 | return NULL; | |
706 | ||
cc09e299 JA |
707 | if (!root->left) |
708 | root->left = rb_first(&root->rb); | |
709 | ||
0871714e JA |
710 | if (root->left) |
711 | return rb_entry(root->left, struct cfq_queue, rb_node); | |
712 | ||
713 | return NULL; | |
cc09e299 JA |
714 | } |
715 | ||
1fa8f6d6 VG |
716 | static struct cfq_group *cfq_rb_first_group(struct cfq_rb_root *root) |
717 | { | |
718 | if (!root->left) | |
719 | root->left = rb_first(&root->rb); | |
720 | ||
721 | if (root->left) | |
722 | return rb_entry_cfqg(root->left); | |
723 | ||
724 | return NULL; | |
725 | } | |
726 | ||
a36e71f9 JA |
727 | static void rb_erase_init(struct rb_node *n, struct rb_root *root) |
728 | { | |
729 | rb_erase(n, root); | |
730 | RB_CLEAR_NODE(n); | |
731 | } | |
732 | ||
cc09e299 JA |
733 | static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root) |
734 | { | |
735 | if (root->left == n) | |
736 | root->left = NULL; | |
a36e71f9 | 737 | rb_erase_init(n, &root->rb); |
aa6f6a3d | 738 | --root->count; |
cc09e299 JA |
739 | } |
740 | ||
1da177e4 LT |
741 | /* |
742 | * would be nice to take fifo expire time into account as well | |
743 | */ | |
5e705374 JA |
744 | static struct request * |
745 | cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
746 | struct request *last) | |
1da177e4 | 747 | { |
21183b07 JA |
748 | struct rb_node *rbnext = rb_next(&last->rb_node); |
749 | struct rb_node *rbprev = rb_prev(&last->rb_node); | |
5e705374 | 750 | struct request *next = NULL, *prev = NULL; |
1da177e4 | 751 | |
21183b07 | 752 | BUG_ON(RB_EMPTY_NODE(&last->rb_node)); |
1da177e4 LT |
753 | |
754 | if (rbprev) | |
5e705374 | 755 | prev = rb_entry_rq(rbprev); |
1da177e4 | 756 | |
21183b07 | 757 | if (rbnext) |
5e705374 | 758 | next = rb_entry_rq(rbnext); |
21183b07 JA |
759 | else { |
760 | rbnext = rb_first(&cfqq->sort_list); | |
761 | if (rbnext && rbnext != &last->rb_node) | |
5e705374 | 762 | next = rb_entry_rq(rbnext); |
21183b07 | 763 | } |
1da177e4 | 764 | |
cf7c25cf | 765 | return cfq_choose_req(cfqd, next, prev, blk_rq_pos(last)); |
1da177e4 LT |
766 | } |
767 | ||
d9e7620e JA |
768 | static unsigned long cfq_slice_offset(struct cfq_data *cfqd, |
769 | struct cfq_queue *cfqq) | |
1da177e4 | 770 | { |
d9e7620e JA |
771 | /* |
772 | * just an approximation, should be ok. | |
773 | */ | |
cdb16e8f | 774 | return (cfqq->cfqg->nr_cfqq - 1) * (cfq_prio_slice(cfqd, 1, 0) - |
464191c6 | 775 | cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio)); |
d9e7620e JA |
776 | } |
777 | ||
1fa8f6d6 VG |
778 | static inline s64 |
779 | cfqg_key(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
780 | { | |
781 | return cfqg->vdisktime - st->min_vdisktime; | |
782 | } | |
783 | ||
784 | static void | |
785 | __cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
786 | { | |
787 | struct rb_node **node = &st->rb.rb_node; | |
788 | struct rb_node *parent = NULL; | |
789 | struct cfq_group *__cfqg; | |
790 | s64 key = cfqg_key(st, cfqg); | |
791 | int left = 1; | |
792 | ||
793 | while (*node != NULL) { | |
794 | parent = *node; | |
795 | __cfqg = rb_entry_cfqg(parent); | |
796 | ||
797 | if (key < cfqg_key(st, __cfqg)) | |
798 | node = &parent->rb_left; | |
799 | else { | |
800 | node = &parent->rb_right; | |
801 | left = 0; | |
802 | } | |
803 | } | |
804 | ||
805 | if (left) | |
806 | st->left = &cfqg->rb_node; | |
807 | ||
808 | rb_link_node(&cfqg->rb_node, parent, node); | |
809 | rb_insert_color(&cfqg->rb_node, &st->rb); | |
810 | } | |
811 | ||
812 | static void | |
813 | cfq_group_service_tree_add(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
814 | { | |
815 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
816 | struct cfq_group *__cfqg; | |
817 | struct rb_node *n; | |
818 | ||
819 | cfqg->nr_cfqq++; | |
820 | if (cfqg->on_st) | |
821 | return; | |
822 | ||
823 | /* | |
824 | * Currently put the group at the end. Later implement something | |
825 | * so that groups get lesser vtime based on their weights, so that | |
826 | * if group does not loose all if it was not continously backlogged. | |
827 | */ | |
828 | n = rb_last(&st->rb); | |
829 | if (n) { | |
830 | __cfqg = rb_entry_cfqg(n); | |
831 | cfqg->vdisktime = __cfqg->vdisktime + CFQ_IDLE_DELAY; | |
832 | } else | |
833 | cfqg->vdisktime = st->min_vdisktime; | |
834 | ||
835 | __cfq_group_service_tree_add(st, cfqg); | |
836 | cfqg->on_st = true; | |
58ff82f3 | 837 | st->total_weight += cfqg->weight; |
1fa8f6d6 VG |
838 | } |
839 | ||
840 | static void | |
841 | cfq_group_service_tree_del(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
842 | { | |
843 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
844 | ||
25bc6b07 VG |
845 | if (st->active == &cfqg->rb_node) |
846 | st->active = NULL; | |
847 | ||
1fa8f6d6 VG |
848 | BUG_ON(cfqg->nr_cfqq < 1); |
849 | cfqg->nr_cfqq--; | |
25bc6b07 | 850 | |
1fa8f6d6 VG |
851 | /* If there are other cfq queues under this group, don't delete it */ |
852 | if (cfqg->nr_cfqq) | |
853 | return; | |
854 | ||
2868ef7b | 855 | cfq_log_cfqg(cfqd, cfqg, "del_from_rr group"); |
1fa8f6d6 | 856 | cfqg->on_st = false; |
58ff82f3 | 857 | st->total_weight -= cfqg->weight; |
1fa8f6d6 VG |
858 | if (!RB_EMPTY_NODE(&cfqg->rb_node)) |
859 | cfq_rb_erase(&cfqg->rb_node, st); | |
dae739eb | 860 | cfqg->saved_workload_slice = 0; |
22084190 | 861 | blkiocg_update_blkio_group_dequeue_stats(&cfqg->blkg, 1); |
dae739eb VG |
862 | } |
863 | ||
864 | static inline unsigned int cfq_cfqq_slice_usage(struct cfq_queue *cfqq) | |
865 | { | |
f75edf2d | 866 | unsigned int slice_used; |
dae739eb VG |
867 | |
868 | /* | |
869 | * Queue got expired before even a single request completed or | |
870 | * got expired immediately after first request completion. | |
871 | */ | |
872 | if (!cfqq->slice_start || cfqq->slice_start == jiffies) { | |
873 | /* | |
874 | * Also charge the seek time incurred to the group, otherwise | |
875 | * if there are mutiple queues in the group, each can dispatch | |
876 | * a single request on seeky media and cause lots of seek time | |
877 | * and group will never know it. | |
878 | */ | |
879 | slice_used = max_t(unsigned, (jiffies - cfqq->dispatch_start), | |
880 | 1); | |
881 | } else { | |
882 | slice_used = jiffies - cfqq->slice_start; | |
f75edf2d VG |
883 | if (slice_used > cfqq->allocated_slice) |
884 | slice_used = cfqq->allocated_slice; | |
dae739eb VG |
885 | } |
886 | ||
22084190 VG |
887 | cfq_log_cfqq(cfqq->cfqd, cfqq, "sl_used=%u sect=%lu", slice_used, |
888 | cfqq->nr_sectors); | |
dae739eb VG |
889 | return slice_used; |
890 | } | |
891 | ||
892 | static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg, | |
893 | struct cfq_queue *cfqq) | |
894 | { | |
895 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
f26bd1f0 VG |
896 | unsigned int used_sl, charge_sl; |
897 | int nr_sync = cfqg->nr_cfqq - cfqg_busy_async_queues(cfqd, cfqg) | |
898 | - cfqg->service_tree_idle.count; | |
899 | ||
900 | BUG_ON(nr_sync < 0); | |
901 | used_sl = charge_sl = cfq_cfqq_slice_usage(cfqq); | |
dae739eb | 902 | |
f26bd1f0 VG |
903 | if (!cfq_cfqq_sync(cfqq) && !nr_sync) |
904 | charge_sl = cfqq->allocated_slice; | |
dae739eb VG |
905 | |
906 | /* Can't update vdisktime while group is on service tree */ | |
907 | cfq_rb_erase(&cfqg->rb_node, st); | |
f26bd1f0 | 908 | cfqg->vdisktime += cfq_scale_slice(charge_sl, cfqg); |
dae739eb VG |
909 | __cfq_group_service_tree_add(st, cfqg); |
910 | ||
911 | /* This group is being expired. Save the context */ | |
912 | if (time_after(cfqd->workload_expires, jiffies)) { | |
913 | cfqg->saved_workload_slice = cfqd->workload_expires | |
914 | - jiffies; | |
915 | cfqg->saved_workload = cfqd->serving_type; | |
916 | cfqg->saved_serving_prio = cfqd->serving_prio; | |
917 | } else | |
918 | cfqg->saved_workload_slice = 0; | |
2868ef7b VG |
919 | |
920 | cfq_log_cfqg(cfqd, cfqg, "served: vt=%llu min_vt=%llu", cfqg->vdisktime, | |
921 | st->min_vdisktime); | |
22084190 VG |
922 | blkiocg_update_blkio_group_stats(&cfqg->blkg, used_sl, |
923 | cfqq->nr_sectors); | |
1fa8f6d6 VG |
924 | } |
925 | ||
25fb5169 VG |
926 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
927 | static inline struct cfq_group *cfqg_of_blkg(struct blkio_group *blkg) | |
928 | { | |
929 | if (blkg) | |
930 | return container_of(blkg, struct cfq_group, blkg); | |
931 | return NULL; | |
932 | } | |
933 | ||
f8d461d6 VG |
934 | void |
935 | cfq_update_blkio_group_weight(struct blkio_group *blkg, unsigned int weight) | |
936 | { | |
937 | cfqg_of_blkg(blkg)->weight = weight; | |
938 | } | |
939 | ||
25fb5169 VG |
940 | static struct cfq_group * |
941 | cfq_find_alloc_cfqg(struct cfq_data *cfqd, struct cgroup *cgroup, int create) | |
942 | { | |
943 | struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup); | |
944 | struct cfq_group *cfqg = NULL; | |
945 | void *key = cfqd; | |
946 | int i, j; | |
947 | struct cfq_rb_root *st; | |
22084190 VG |
948 | struct backing_dev_info *bdi = &cfqd->queue->backing_dev_info; |
949 | unsigned int major, minor; | |
25fb5169 | 950 | |
25fb5169 | 951 | cfqg = cfqg_of_blkg(blkiocg_lookup_group(blkcg, key)); |
a74b2ada RB |
952 | if (cfqg && !cfqg->blkg.dev && bdi->dev && dev_name(bdi->dev)) { |
953 | sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor); | |
954 | cfqg->blkg.dev = MKDEV(major, minor); | |
955 | goto done; | |
956 | } | |
25fb5169 VG |
957 | if (cfqg || !create) |
958 | goto done; | |
959 | ||
960 | cfqg = kzalloc_node(sizeof(*cfqg), GFP_ATOMIC, cfqd->queue->node); | |
961 | if (!cfqg) | |
962 | goto done; | |
963 | ||
964 | cfqg->weight = blkcg->weight; | |
965 | for_each_cfqg_st(cfqg, i, j, st) | |
966 | *st = CFQ_RB_ROOT; | |
967 | RB_CLEAR_NODE(&cfqg->rb_node); | |
968 | ||
b1c35769 VG |
969 | /* |
970 | * Take the initial reference that will be released on destroy | |
971 | * This can be thought of a joint reference by cgroup and | |
972 | * elevator which will be dropped by either elevator exit | |
973 | * or cgroup deletion path depending on who is exiting first. | |
974 | */ | |
975 | atomic_set(&cfqg->ref, 1); | |
976 | ||
25fb5169 | 977 | /* Add group onto cgroup list */ |
22084190 VG |
978 | sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor); |
979 | blkiocg_add_blkio_group(blkcg, &cfqg->blkg, (void *)cfqd, | |
980 | MKDEV(major, minor)); | |
25fb5169 VG |
981 | |
982 | /* Add group on cfqd list */ | |
983 | hlist_add_head(&cfqg->cfqd_node, &cfqd->cfqg_list); | |
984 | ||
985 | done: | |
25fb5169 VG |
986 | return cfqg; |
987 | } | |
988 | ||
989 | /* | |
990 | * Search for the cfq group current task belongs to. If create = 1, then also | |
991 | * create the cfq group if it does not exist. request_queue lock must be held. | |
992 | */ | |
993 | static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd, int create) | |
994 | { | |
995 | struct cgroup *cgroup; | |
996 | struct cfq_group *cfqg = NULL; | |
997 | ||
998 | rcu_read_lock(); | |
999 | cgroup = task_cgroup(current, blkio_subsys_id); | |
1000 | cfqg = cfq_find_alloc_cfqg(cfqd, cgroup, create); | |
1001 | if (!cfqg && create) | |
1002 | cfqg = &cfqd->root_group; | |
1003 | rcu_read_unlock(); | |
1004 | return cfqg; | |
1005 | } | |
1006 | ||
1007 | static void cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) | |
1008 | { | |
1009 | /* Currently, all async queues are mapped to root group */ | |
1010 | if (!cfq_cfqq_sync(cfqq)) | |
1011 | cfqg = &cfqq->cfqd->root_group; | |
1012 | ||
1013 | cfqq->cfqg = cfqg; | |
b1c35769 VG |
1014 | /* cfqq reference on cfqg */ |
1015 | atomic_inc(&cfqq->cfqg->ref); | |
1016 | } | |
1017 | ||
1018 | static void cfq_put_cfqg(struct cfq_group *cfqg) | |
1019 | { | |
1020 | struct cfq_rb_root *st; | |
1021 | int i, j; | |
1022 | ||
1023 | BUG_ON(atomic_read(&cfqg->ref) <= 0); | |
1024 | if (!atomic_dec_and_test(&cfqg->ref)) | |
1025 | return; | |
1026 | for_each_cfqg_st(cfqg, i, j, st) | |
1027 | BUG_ON(!RB_EMPTY_ROOT(&st->rb) || st->active != NULL); | |
1028 | kfree(cfqg); | |
1029 | } | |
1030 | ||
1031 | static void cfq_destroy_cfqg(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
1032 | { | |
1033 | /* Something wrong if we are trying to remove same group twice */ | |
1034 | BUG_ON(hlist_unhashed(&cfqg->cfqd_node)); | |
1035 | ||
1036 | hlist_del_init(&cfqg->cfqd_node); | |
1037 | ||
1038 | /* | |
1039 | * Put the reference taken at the time of creation so that when all | |
1040 | * queues are gone, group can be destroyed. | |
1041 | */ | |
1042 | cfq_put_cfqg(cfqg); | |
1043 | } | |
1044 | ||
1045 | static void cfq_release_cfq_groups(struct cfq_data *cfqd) | |
1046 | { | |
1047 | struct hlist_node *pos, *n; | |
1048 | struct cfq_group *cfqg; | |
1049 | ||
1050 | hlist_for_each_entry_safe(cfqg, pos, n, &cfqd->cfqg_list, cfqd_node) { | |
1051 | /* | |
1052 | * If cgroup removal path got to blk_group first and removed | |
1053 | * it from cgroup list, then it will take care of destroying | |
1054 | * cfqg also. | |
1055 | */ | |
1056 | if (!blkiocg_del_blkio_group(&cfqg->blkg)) | |
1057 | cfq_destroy_cfqg(cfqd, cfqg); | |
1058 | } | |
25fb5169 | 1059 | } |
b1c35769 VG |
1060 | |
1061 | /* | |
1062 | * Blk cgroup controller notification saying that blkio_group object is being | |
1063 | * delinked as associated cgroup object is going away. That also means that | |
1064 | * no new IO will come in this group. So get rid of this group as soon as | |
1065 | * any pending IO in the group is finished. | |
1066 | * | |
1067 | * This function is called under rcu_read_lock(). key is the rcu protected | |
1068 | * pointer. That means "key" is a valid cfq_data pointer as long as we are rcu | |
1069 | * read lock. | |
1070 | * | |
1071 | * "key" was fetched from blkio_group under blkio_cgroup->lock. That means | |
1072 | * it should not be NULL as even if elevator was exiting, cgroup deltion | |
1073 | * path got to it first. | |
1074 | */ | |
1075 | void cfq_unlink_blkio_group(void *key, struct blkio_group *blkg) | |
1076 | { | |
1077 | unsigned long flags; | |
1078 | struct cfq_data *cfqd = key; | |
1079 | ||
1080 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
1081 | cfq_destroy_cfqg(cfqd, cfqg_of_blkg(blkg)); | |
1082 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
1083 | } | |
1084 | ||
25fb5169 VG |
1085 | #else /* GROUP_IOSCHED */ |
1086 | static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd, int create) | |
1087 | { | |
1088 | return &cfqd->root_group; | |
1089 | } | |
1090 | static inline void | |
1091 | cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) { | |
1092 | cfqq->cfqg = cfqg; | |
1093 | } | |
1094 | ||
b1c35769 VG |
1095 | static void cfq_release_cfq_groups(struct cfq_data *cfqd) {} |
1096 | static inline void cfq_put_cfqg(struct cfq_group *cfqg) {} | |
1097 | ||
25fb5169 VG |
1098 | #endif /* GROUP_IOSCHED */ |
1099 | ||
498d3aa2 | 1100 | /* |
c0324a02 | 1101 | * The cfqd->service_trees holds all pending cfq_queue's that have |
498d3aa2 JA |
1102 | * requests waiting to be processed. It is sorted in the order that |
1103 | * we will service the queues. | |
1104 | */ | |
a36e71f9 | 1105 | static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
a6151c3a | 1106 | bool add_front) |
d9e7620e | 1107 | { |
0871714e JA |
1108 | struct rb_node **p, *parent; |
1109 | struct cfq_queue *__cfqq; | |
d9e7620e | 1110 | unsigned long rb_key; |
c0324a02 | 1111 | struct cfq_rb_root *service_tree; |
498d3aa2 | 1112 | int left; |
dae739eb | 1113 | int new_cfqq = 1; |
ae30c286 VG |
1114 | int group_changed = 0; |
1115 | ||
1116 | #ifdef CONFIG_CFQ_GROUP_IOSCHED | |
1117 | if (!cfqd->cfq_group_isolation | |
1118 | && cfqq_type(cfqq) == SYNC_NOIDLE_WORKLOAD | |
1119 | && cfqq->cfqg && cfqq->cfqg != &cfqd->root_group) { | |
1120 | /* Move this cfq to root group */ | |
1121 | cfq_log_cfqq(cfqd, cfqq, "moving to root group"); | |
1122 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) | |
1123 | cfq_group_service_tree_del(cfqd, cfqq->cfqg); | |
1124 | cfqq->orig_cfqg = cfqq->cfqg; | |
1125 | cfqq->cfqg = &cfqd->root_group; | |
1126 | atomic_inc(&cfqd->root_group.ref); | |
1127 | group_changed = 1; | |
1128 | } else if (!cfqd->cfq_group_isolation | |
1129 | && cfqq_type(cfqq) == SYNC_WORKLOAD && cfqq->orig_cfqg) { | |
1130 | /* cfqq is sequential now needs to go to its original group */ | |
1131 | BUG_ON(cfqq->cfqg != &cfqd->root_group); | |
1132 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) | |
1133 | cfq_group_service_tree_del(cfqd, cfqq->cfqg); | |
1134 | cfq_put_cfqg(cfqq->cfqg); | |
1135 | cfqq->cfqg = cfqq->orig_cfqg; | |
1136 | cfqq->orig_cfqg = NULL; | |
1137 | group_changed = 1; | |
1138 | cfq_log_cfqq(cfqd, cfqq, "moved to origin group"); | |
1139 | } | |
1140 | #endif | |
d9e7620e | 1141 | |
cdb16e8f | 1142 | service_tree = service_tree_for(cfqq->cfqg, cfqq_prio(cfqq), |
65b32a57 | 1143 | cfqq_type(cfqq)); |
0871714e JA |
1144 | if (cfq_class_idle(cfqq)) { |
1145 | rb_key = CFQ_IDLE_DELAY; | |
aa6f6a3d | 1146 | parent = rb_last(&service_tree->rb); |
0871714e JA |
1147 | if (parent && parent != &cfqq->rb_node) { |
1148 | __cfqq = rb_entry(parent, struct cfq_queue, rb_node); | |
1149 | rb_key += __cfqq->rb_key; | |
1150 | } else | |
1151 | rb_key += jiffies; | |
1152 | } else if (!add_front) { | |
b9c8946b JA |
1153 | /* |
1154 | * Get our rb key offset. Subtract any residual slice | |
1155 | * value carried from last service. A negative resid | |
1156 | * count indicates slice overrun, and this should position | |
1157 | * the next service time further away in the tree. | |
1158 | */ | |
edd75ffd | 1159 | rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies; |
b9c8946b | 1160 | rb_key -= cfqq->slice_resid; |
edd75ffd | 1161 | cfqq->slice_resid = 0; |
48e025e6 CZ |
1162 | } else { |
1163 | rb_key = -HZ; | |
aa6f6a3d | 1164 | __cfqq = cfq_rb_first(service_tree); |
48e025e6 CZ |
1165 | rb_key += __cfqq ? __cfqq->rb_key : jiffies; |
1166 | } | |
1da177e4 | 1167 | |
d9e7620e | 1168 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) { |
dae739eb | 1169 | new_cfqq = 0; |
99f9628a | 1170 | /* |
d9e7620e | 1171 | * same position, nothing more to do |
99f9628a | 1172 | */ |
c0324a02 CZ |
1173 | if (rb_key == cfqq->rb_key && |
1174 | cfqq->service_tree == service_tree) | |
d9e7620e | 1175 | return; |
1da177e4 | 1176 | |
aa6f6a3d CZ |
1177 | cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree); |
1178 | cfqq->service_tree = NULL; | |
1da177e4 | 1179 | } |
d9e7620e | 1180 | |
498d3aa2 | 1181 | left = 1; |
0871714e | 1182 | parent = NULL; |
aa6f6a3d CZ |
1183 | cfqq->service_tree = service_tree; |
1184 | p = &service_tree->rb.rb_node; | |
d9e7620e | 1185 | while (*p) { |
67060e37 | 1186 | struct rb_node **n; |
cc09e299 | 1187 | |
d9e7620e JA |
1188 | parent = *p; |
1189 | __cfqq = rb_entry(parent, struct cfq_queue, rb_node); | |
1190 | ||
0c534e0a | 1191 | /* |
c0324a02 | 1192 | * sort by key, that represents service time. |
0c534e0a | 1193 | */ |
c0324a02 | 1194 | if (time_before(rb_key, __cfqq->rb_key)) |
67060e37 | 1195 | n = &(*p)->rb_left; |
c0324a02 | 1196 | else { |
67060e37 | 1197 | n = &(*p)->rb_right; |
cc09e299 | 1198 | left = 0; |
c0324a02 | 1199 | } |
67060e37 JA |
1200 | |
1201 | p = n; | |
d9e7620e JA |
1202 | } |
1203 | ||
cc09e299 | 1204 | if (left) |
aa6f6a3d | 1205 | service_tree->left = &cfqq->rb_node; |
cc09e299 | 1206 | |
d9e7620e JA |
1207 | cfqq->rb_key = rb_key; |
1208 | rb_link_node(&cfqq->rb_node, parent, p); | |
aa6f6a3d CZ |
1209 | rb_insert_color(&cfqq->rb_node, &service_tree->rb); |
1210 | service_tree->count++; | |
ae30c286 | 1211 | if ((add_front || !new_cfqq) && !group_changed) |
dae739eb | 1212 | return; |
1fa8f6d6 | 1213 | cfq_group_service_tree_add(cfqd, cfqq->cfqg); |
1da177e4 LT |
1214 | } |
1215 | ||
a36e71f9 | 1216 | static struct cfq_queue * |
f2d1f0ae JA |
1217 | cfq_prio_tree_lookup(struct cfq_data *cfqd, struct rb_root *root, |
1218 | sector_t sector, struct rb_node **ret_parent, | |
1219 | struct rb_node ***rb_link) | |
a36e71f9 | 1220 | { |
a36e71f9 JA |
1221 | struct rb_node **p, *parent; |
1222 | struct cfq_queue *cfqq = NULL; | |
1223 | ||
1224 | parent = NULL; | |
1225 | p = &root->rb_node; | |
1226 | while (*p) { | |
1227 | struct rb_node **n; | |
1228 | ||
1229 | parent = *p; | |
1230 | cfqq = rb_entry(parent, struct cfq_queue, p_node); | |
1231 | ||
1232 | /* | |
1233 | * Sort strictly based on sector. Smallest to the left, | |
1234 | * largest to the right. | |
1235 | */ | |
2e46e8b2 | 1236 | if (sector > blk_rq_pos(cfqq->next_rq)) |
a36e71f9 | 1237 | n = &(*p)->rb_right; |
2e46e8b2 | 1238 | else if (sector < blk_rq_pos(cfqq->next_rq)) |
a36e71f9 JA |
1239 | n = &(*p)->rb_left; |
1240 | else | |
1241 | break; | |
1242 | p = n; | |
3ac6c9f8 | 1243 | cfqq = NULL; |
a36e71f9 JA |
1244 | } |
1245 | ||
1246 | *ret_parent = parent; | |
1247 | if (rb_link) | |
1248 | *rb_link = p; | |
3ac6c9f8 | 1249 | return cfqq; |
a36e71f9 JA |
1250 | } |
1251 | ||
1252 | static void cfq_prio_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1253 | { | |
a36e71f9 JA |
1254 | struct rb_node **p, *parent; |
1255 | struct cfq_queue *__cfqq; | |
1256 | ||
f2d1f0ae JA |
1257 | if (cfqq->p_root) { |
1258 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
1259 | cfqq->p_root = NULL; | |
1260 | } | |
a36e71f9 JA |
1261 | |
1262 | if (cfq_class_idle(cfqq)) | |
1263 | return; | |
1264 | if (!cfqq->next_rq) | |
1265 | return; | |
1266 | ||
f2d1f0ae | 1267 | cfqq->p_root = &cfqd->prio_trees[cfqq->org_ioprio]; |
2e46e8b2 TH |
1268 | __cfqq = cfq_prio_tree_lookup(cfqd, cfqq->p_root, |
1269 | blk_rq_pos(cfqq->next_rq), &parent, &p); | |
3ac6c9f8 JA |
1270 | if (!__cfqq) { |
1271 | rb_link_node(&cfqq->p_node, parent, p); | |
f2d1f0ae JA |
1272 | rb_insert_color(&cfqq->p_node, cfqq->p_root); |
1273 | } else | |
1274 | cfqq->p_root = NULL; | |
a36e71f9 JA |
1275 | } |
1276 | ||
498d3aa2 JA |
1277 | /* |
1278 | * Update cfqq's position in the service tree. | |
1279 | */ | |
edd75ffd | 1280 | static void cfq_resort_rr_list(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
6d048f53 | 1281 | { |
6d048f53 JA |
1282 | /* |
1283 | * Resorting requires the cfqq to be on the RR list already. | |
1284 | */ | |
a36e71f9 | 1285 | if (cfq_cfqq_on_rr(cfqq)) { |
edd75ffd | 1286 | cfq_service_tree_add(cfqd, cfqq, 0); |
a36e71f9 JA |
1287 | cfq_prio_tree_add(cfqd, cfqq); |
1288 | } | |
6d048f53 JA |
1289 | } |
1290 | ||
1da177e4 LT |
1291 | /* |
1292 | * add to busy list of queues for service, trying to be fair in ordering | |
22e2c507 | 1293 | * the pending list according to last request service |
1da177e4 | 1294 | */ |
febffd61 | 1295 | static void cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 1296 | { |
7b679138 | 1297 | cfq_log_cfqq(cfqd, cfqq, "add_to_rr"); |
3b18152c JA |
1298 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
1299 | cfq_mark_cfqq_on_rr(cfqq); | |
1da177e4 LT |
1300 | cfqd->busy_queues++; |
1301 | ||
edd75ffd | 1302 | cfq_resort_rr_list(cfqd, cfqq); |
1da177e4 LT |
1303 | } |
1304 | ||
498d3aa2 JA |
1305 | /* |
1306 | * Called when the cfqq no longer has requests pending, remove it from | |
1307 | * the service tree. | |
1308 | */ | |
febffd61 | 1309 | static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 1310 | { |
7b679138 | 1311 | cfq_log_cfqq(cfqd, cfqq, "del_from_rr"); |
3b18152c JA |
1312 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
1313 | cfq_clear_cfqq_on_rr(cfqq); | |
1da177e4 | 1314 | |
aa6f6a3d CZ |
1315 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) { |
1316 | cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree); | |
1317 | cfqq->service_tree = NULL; | |
1318 | } | |
f2d1f0ae JA |
1319 | if (cfqq->p_root) { |
1320 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
1321 | cfqq->p_root = NULL; | |
1322 | } | |
d9e7620e | 1323 | |
1fa8f6d6 | 1324 | cfq_group_service_tree_del(cfqd, cfqq->cfqg); |
1da177e4 LT |
1325 | BUG_ON(!cfqd->busy_queues); |
1326 | cfqd->busy_queues--; | |
1327 | } | |
1328 | ||
1329 | /* | |
1330 | * rb tree support functions | |
1331 | */ | |
febffd61 | 1332 | static void cfq_del_rq_rb(struct request *rq) |
1da177e4 | 1333 | { |
5e705374 | 1334 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
5e705374 | 1335 | const int sync = rq_is_sync(rq); |
1da177e4 | 1336 | |
b4878f24 JA |
1337 | BUG_ON(!cfqq->queued[sync]); |
1338 | cfqq->queued[sync]--; | |
1da177e4 | 1339 | |
5e705374 | 1340 | elv_rb_del(&cfqq->sort_list, rq); |
1da177e4 | 1341 | |
f04a6424 VG |
1342 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) { |
1343 | /* | |
1344 | * Queue will be deleted from service tree when we actually | |
1345 | * expire it later. Right now just remove it from prio tree | |
1346 | * as it is empty. | |
1347 | */ | |
1348 | if (cfqq->p_root) { | |
1349 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
1350 | cfqq->p_root = NULL; | |
1351 | } | |
1352 | } | |
1da177e4 LT |
1353 | } |
1354 | ||
5e705374 | 1355 | static void cfq_add_rq_rb(struct request *rq) |
1da177e4 | 1356 | { |
5e705374 | 1357 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
1da177e4 | 1358 | struct cfq_data *cfqd = cfqq->cfqd; |
a36e71f9 | 1359 | struct request *__alias, *prev; |
1da177e4 | 1360 | |
5380a101 | 1361 | cfqq->queued[rq_is_sync(rq)]++; |
1da177e4 LT |
1362 | |
1363 | /* | |
1364 | * looks a little odd, but the first insert might return an alias. | |
1365 | * if that happens, put the alias on the dispatch list | |
1366 | */ | |
21183b07 | 1367 | while ((__alias = elv_rb_add(&cfqq->sort_list, rq)) != NULL) |
5e705374 | 1368 | cfq_dispatch_insert(cfqd->queue, __alias); |
5fccbf61 JA |
1369 | |
1370 | if (!cfq_cfqq_on_rr(cfqq)) | |
1371 | cfq_add_cfqq_rr(cfqd, cfqq); | |
5044eed4 JA |
1372 | |
1373 | /* | |
1374 | * check if this request is a better next-serve candidate | |
1375 | */ | |
a36e71f9 | 1376 | prev = cfqq->next_rq; |
cf7c25cf | 1377 | cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq, cfqd->last_position); |
a36e71f9 JA |
1378 | |
1379 | /* | |
1380 | * adjust priority tree position, if ->next_rq changes | |
1381 | */ | |
1382 | if (prev != cfqq->next_rq) | |
1383 | cfq_prio_tree_add(cfqd, cfqq); | |
1384 | ||
5044eed4 | 1385 | BUG_ON(!cfqq->next_rq); |
1da177e4 LT |
1386 | } |
1387 | ||
febffd61 | 1388 | static void cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq) |
1da177e4 | 1389 | { |
5380a101 JA |
1390 | elv_rb_del(&cfqq->sort_list, rq); |
1391 | cfqq->queued[rq_is_sync(rq)]--; | |
5e705374 | 1392 | cfq_add_rq_rb(rq); |
1da177e4 LT |
1393 | } |
1394 | ||
206dc69b JA |
1395 | static struct request * |
1396 | cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio) | |
1da177e4 | 1397 | { |
206dc69b | 1398 | struct task_struct *tsk = current; |
91fac317 | 1399 | struct cfq_io_context *cic; |
206dc69b | 1400 | struct cfq_queue *cfqq; |
1da177e4 | 1401 | |
4ac845a2 | 1402 | cic = cfq_cic_lookup(cfqd, tsk->io_context); |
91fac317 VT |
1403 | if (!cic) |
1404 | return NULL; | |
1405 | ||
1406 | cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); | |
89850f7e JA |
1407 | if (cfqq) { |
1408 | sector_t sector = bio->bi_sector + bio_sectors(bio); | |
1409 | ||
21183b07 | 1410 | return elv_rb_find(&cfqq->sort_list, sector); |
89850f7e | 1411 | } |
1da177e4 | 1412 | |
1da177e4 LT |
1413 | return NULL; |
1414 | } | |
1415 | ||
165125e1 | 1416 | static void cfq_activate_request(struct request_queue *q, struct request *rq) |
1da177e4 | 1417 | { |
22e2c507 | 1418 | struct cfq_data *cfqd = q->elevator->elevator_data; |
3b18152c | 1419 | |
53c583d2 | 1420 | cfqd->rq_in_driver++; |
7b679138 | 1421 | cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "activate rq, drv=%d", |
53c583d2 | 1422 | cfqd->rq_in_driver); |
25776e35 | 1423 | |
5b93629b | 1424 | cfqd->last_position = blk_rq_pos(rq) + blk_rq_sectors(rq); |
1da177e4 LT |
1425 | } |
1426 | ||
165125e1 | 1427 | static void cfq_deactivate_request(struct request_queue *q, struct request *rq) |
1da177e4 | 1428 | { |
b4878f24 JA |
1429 | struct cfq_data *cfqd = q->elevator->elevator_data; |
1430 | ||
53c583d2 CZ |
1431 | WARN_ON(!cfqd->rq_in_driver); |
1432 | cfqd->rq_in_driver--; | |
7b679138 | 1433 | cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "deactivate rq, drv=%d", |
53c583d2 | 1434 | cfqd->rq_in_driver); |
1da177e4 LT |
1435 | } |
1436 | ||
b4878f24 | 1437 | static void cfq_remove_request(struct request *rq) |
1da177e4 | 1438 | { |
5e705374 | 1439 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
21183b07 | 1440 | |
5e705374 JA |
1441 | if (cfqq->next_rq == rq) |
1442 | cfqq->next_rq = cfq_find_next_rq(cfqq->cfqd, cfqq, rq); | |
1da177e4 | 1443 | |
b4878f24 | 1444 | list_del_init(&rq->queuelist); |
5e705374 | 1445 | cfq_del_rq_rb(rq); |
374f84ac | 1446 | |
45333d5a | 1447 | cfqq->cfqd->rq_queued--; |
374f84ac JA |
1448 | if (rq_is_meta(rq)) { |
1449 | WARN_ON(!cfqq->meta_pending); | |
1450 | cfqq->meta_pending--; | |
1451 | } | |
1da177e4 LT |
1452 | } |
1453 | ||
165125e1 JA |
1454 | static int cfq_merge(struct request_queue *q, struct request **req, |
1455 | struct bio *bio) | |
1da177e4 LT |
1456 | { |
1457 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1458 | struct request *__rq; | |
1da177e4 | 1459 | |
206dc69b | 1460 | __rq = cfq_find_rq_fmerge(cfqd, bio); |
22e2c507 | 1461 | if (__rq && elv_rq_merge_ok(__rq, bio)) { |
9817064b JA |
1462 | *req = __rq; |
1463 | return ELEVATOR_FRONT_MERGE; | |
1da177e4 LT |
1464 | } |
1465 | ||
1466 | return ELEVATOR_NO_MERGE; | |
1da177e4 LT |
1467 | } |
1468 | ||
165125e1 | 1469 | static void cfq_merged_request(struct request_queue *q, struct request *req, |
21183b07 | 1470 | int type) |
1da177e4 | 1471 | { |
21183b07 | 1472 | if (type == ELEVATOR_FRONT_MERGE) { |
5e705374 | 1473 | struct cfq_queue *cfqq = RQ_CFQQ(req); |
1da177e4 | 1474 | |
5e705374 | 1475 | cfq_reposition_rq_rb(cfqq, req); |
1da177e4 | 1476 | } |
1da177e4 LT |
1477 | } |
1478 | ||
1479 | static void | |
165125e1 | 1480 | cfq_merged_requests(struct request_queue *q, struct request *rq, |
1da177e4 LT |
1481 | struct request *next) |
1482 | { | |
cf7c25cf | 1483 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 JA |
1484 | /* |
1485 | * reposition in fifo if next is older than rq | |
1486 | */ | |
1487 | if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && | |
30996f40 | 1488 | time_before(rq_fifo_time(next), rq_fifo_time(rq))) { |
22e2c507 | 1489 | list_move(&rq->queuelist, &next->queuelist); |
30996f40 JA |
1490 | rq_set_fifo_time(rq, rq_fifo_time(next)); |
1491 | } | |
22e2c507 | 1492 | |
cf7c25cf CZ |
1493 | if (cfqq->next_rq == next) |
1494 | cfqq->next_rq = rq; | |
b4878f24 | 1495 | cfq_remove_request(next); |
22e2c507 JA |
1496 | } |
1497 | ||
165125e1 | 1498 | static int cfq_allow_merge(struct request_queue *q, struct request *rq, |
da775265 JA |
1499 | struct bio *bio) |
1500 | { | |
1501 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
91fac317 | 1502 | struct cfq_io_context *cic; |
da775265 | 1503 | struct cfq_queue *cfqq; |
da775265 JA |
1504 | |
1505 | /* | |
ec8acb69 | 1506 | * Disallow merge of a sync bio into an async request. |
da775265 | 1507 | */ |
91fac317 | 1508 | if (cfq_bio_sync(bio) && !rq_is_sync(rq)) |
a6151c3a | 1509 | return false; |
da775265 JA |
1510 | |
1511 | /* | |
719d3402 JA |
1512 | * Lookup the cfqq that this bio will be queued with. Allow |
1513 | * merge only if rq is queued there. | |
da775265 | 1514 | */ |
4ac845a2 | 1515 | cic = cfq_cic_lookup(cfqd, current->io_context); |
91fac317 | 1516 | if (!cic) |
a6151c3a | 1517 | return false; |
719d3402 | 1518 | |
91fac317 | 1519 | cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); |
a6151c3a | 1520 | return cfqq == RQ_CFQQ(rq); |
da775265 JA |
1521 | } |
1522 | ||
febffd61 JA |
1523 | static void __cfq_set_active_queue(struct cfq_data *cfqd, |
1524 | struct cfq_queue *cfqq) | |
22e2c507 JA |
1525 | { |
1526 | if (cfqq) { | |
b1ffe737 DS |
1527 | cfq_log_cfqq(cfqd, cfqq, "set_active wl_prio:%d wl_type:%d", |
1528 | cfqd->serving_prio, cfqd->serving_type); | |
dae739eb VG |
1529 | cfqq->slice_start = 0; |
1530 | cfqq->dispatch_start = jiffies; | |
f75edf2d | 1531 | cfqq->allocated_slice = 0; |
22e2c507 | 1532 | cfqq->slice_end = 0; |
2f5cb738 | 1533 | cfqq->slice_dispatch = 0; |
22084190 | 1534 | cfqq->nr_sectors = 0; |
2f5cb738 | 1535 | |
2f5cb738 | 1536 | cfq_clear_cfqq_wait_request(cfqq); |
b029195d | 1537 | cfq_clear_cfqq_must_dispatch(cfqq); |
3b18152c JA |
1538 | cfq_clear_cfqq_must_alloc_slice(cfqq); |
1539 | cfq_clear_cfqq_fifo_expire(cfqq); | |
44f7c160 | 1540 | cfq_mark_cfqq_slice_new(cfqq); |
2f5cb738 JA |
1541 | |
1542 | del_timer(&cfqd->idle_slice_timer); | |
22e2c507 JA |
1543 | } |
1544 | ||
1545 | cfqd->active_queue = cfqq; | |
1546 | } | |
1547 | ||
7b14e3b5 JA |
1548 | /* |
1549 | * current cfqq expired its slice (or was too idle), select new one | |
1550 | */ | |
1551 | static void | |
1552 | __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
a6151c3a | 1553 | bool timed_out) |
7b14e3b5 | 1554 | { |
7b679138 JA |
1555 | cfq_log_cfqq(cfqd, cfqq, "slice expired t=%d", timed_out); |
1556 | ||
7b14e3b5 JA |
1557 | if (cfq_cfqq_wait_request(cfqq)) |
1558 | del_timer(&cfqd->idle_slice_timer); | |
1559 | ||
7b14e3b5 | 1560 | cfq_clear_cfqq_wait_request(cfqq); |
f75edf2d | 1561 | cfq_clear_cfqq_wait_busy(cfqq); |
7b14e3b5 | 1562 | |
ae54abed SL |
1563 | /* |
1564 | * If this cfqq is shared between multiple processes, check to | |
1565 | * make sure that those processes are still issuing I/Os within | |
1566 | * the mean seek distance. If not, it may be time to break the | |
1567 | * queues apart again. | |
1568 | */ | |
1569 | if (cfq_cfqq_coop(cfqq) && CFQQ_SEEKY(cfqq)) | |
1570 | cfq_mark_cfqq_split_coop(cfqq); | |
1571 | ||
7b14e3b5 | 1572 | /* |
6084cdda | 1573 | * store what was left of this slice, if the queue idled/timed out |
7b14e3b5 | 1574 | */ |
7b679138 | 1575 | if (timed_out && !cfq_cfqq_slice_new(cfqq)) { |
c5b680f3 | 1576 | cfqq->slice_resid = cfqq->slice_end - jiffies; |
7b679138 JA |
1577 | cfq_log_cfqq(cfqd, cfqq, "resid=%ld", cfqq->slice_resid); |
1578 | } | |
7b14e3b5 | 1579 | |
dae739eb VG |
1580 | cfq_group_served(cfqd, cfqq->cfqg, cfqq); |
1581 | ||
f04a6424 VG |
1582 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) |
1583 | cfq_del_cfqq_rr(cfqd, cfqq); | |
1584 | ||
edd75ffd | 1585 | cfq_resort_rr_list(cfqd, cfqq); |
7b14e3b5 JA |
1586 | |
1587 | if (cfqq == cfqd->active_queue) | |
1588 | cfqd->active_queue = NULL; | |
1589 | ||
dae739eb VG |
1590 | if (&cfqq->cfqg->rb_node == cfqd->grp_service_tree.active) |
1591 | cfqd->grp_service_tree.active = NULL; | |
1592 | ||
7b14e3b5 JA |
1593 | if (cfqd->active_cic) { |
1594 | put_io_context(cfqd->active_cic->ioc); | |
1595 | cfqd->active_cic = NULL; | |
1596 | } | |
7b14e3b5 JA |
1597 | } |
1598 | ||
a6151c3a | 1599 | static inline void cfq_slice_expired(struct cfq_data *cfqd, bool timed_out) |
7b14e3b5 JA |
1600 | { |
1601 | struct cfq_queue *cfqq = cfqd->active_queue; | |
1602 | ||
1603 | if (cfqq) | |
6084cdda | 1604 | __cfq_slice_expired(cfqd, cfqq, timed_out); |
7b14e3b5 JA |
1605 | } |
1606 | ||
498d3aa2 JA |
1607 | /* |
1608 | * Get next queue for service. Unless we have a queue preemption, | |
1609 | * we'll simply select the first cfqq in the service tree. | |
1610 | */ | |
6d048f53 | 1611 | static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd) |
22e2c507 | 1612 | { |
c0324a02 | 1613 | struct cfq_rb_root *service_tree = |
cdb16e8f | 1614 | service_tree_for(cfqd->serving_group, cfqd->serving_prio, |
65b32a57 | 1615 | cfqd->serving_type); |
d9e7620e | 1616 | |
f04a6424 VG |
1617 | if (!cfqd->rq_queued) |
1618 | return NULL; | |
1619 | ||
1fa8f6d6 VG |
1620 | /* There is nothing to dispatch */ |
1621 | if (!service_tree) | |
1622 | return NULL; | |
c0324a02 CZ |
1623 | if (RB_EMPTY_ROOT(&service_tree->rb)) |
1624 | return NULL; | |
1625 | return cfq_rb_first(service_tree); | |
6d048f53 JA |
1626 | } |
1627 | ||
f04a6424 VG |
1628 | static struct cfq_queue *cfq_get_next_queue_forced(struct cfq_data *cfqd) |
1629 | { | |
25fb5169 | 1630 | struct cfq_group *cfqg; |
f04a6424 VG |
1631 | struct cfq_queue *cfqq; |
1632 | int i, j; | |
1633 | struct cfq_rb_root *st; | |
1634 | ||
1635 | if (!cfqd->rq_queued) | |
1636 | return NULL; | |
1637 | ||
25fb5169 VG |
1638 | cfqg = cfq_get_next_cfqg(cfqd); |
1639 | if (!cfqg) | |
1640 | return NULL; | |
1641 | ||
f04a6424 VG |
1642 | for_each_cfqg_st(cfqg, i, j, st) |
1643 | if ((cfqq = cfq_rb_first(st)) != NULL) | |
1644 | return cfqq; | |
1645 | return NULL; | |
1646 | } | |
1647 | ||
498d3aa2 JA |
1648 | /* |
1649 | * Get and set a new active queue for service. | |
1650 | */ | |
a36e71f9 JA |
1651 | static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd, |
1652 | struct cfq_queue *cfqq) | |
6d048f53 | 1653 | { |
e00ef799 | 1654 | if (!cfqq) |
a36e71f9 | 1655 | cfqq = cfq_get_next_queue(cfqd); |
6d048f53 | 1656 | |
22e2c507 | 1657 | __cfq_set_active_queue(cfqd, cfqq); |
3b18152c | 1658 | return cfqq; |
22e2c507 JA |
1659 | } |
1660 | ||
d9e7620e JA |
1661 | static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd, |
1662 | struct request *rq) | |
1663 | { | |
83096ebf TH |
1664 | if (blk_rq_pos(rq) >= cfqd->last_position) |
1665 | return blk_rq_pos(rq) - cfqd->last_position; | |
d9e7620e | 1666 | else |
83096ebf | 1667 | return cfqd->last_position - blk_rq_pos(rq); |
d9e7620e JA |
1668 | } |
1669 | ||
b2c18e1e | 1670 | static inline int cfq_rq_close(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
e9ce335d | 1671 | struct request *rq) |
6d048f53 | 1672 | { |
e9ce335d | 1673 | return cfq_dist_from_last(cfqd, rq) <= CFQQ_CLOSE_THR; |
6d048f53 JA |
1674 | } |
1675 | ||
a36e71f9 JA |
1676 | static struct cfq_queue *cfqq_close(struct cfq_data *cfqd, |
1677 | struct cfq_queue *cur_cfqq) | |
1678 | { | |
f2d1f0ae | 1679 | struct rb_root *root = &cfqd->prio_trees[cur_cfqq->org_ioprio]; |
a36e71f9 JA |
1680 | struct rb_node *parent, *node; |
1681 | struct cfq_queue *__cfqq; | |
1682 | sector_t sector = cfqd->last_position; | |
1683 | ||
1684 | if (RB_EMPTY_ROOT(root)) | |
1685 | return NULL; | |
1686 | ||
1687 | /* | |
1688 | * First, if we find a request starting at the end of the last | |
1689 | * request, choose it. | |
1690 | */ | |
f2d1f0ae | 1691 | __cfqq = cfq_prio_tree_lookup(cfqd, root, sector, &parent, NULL); |
a36e71f9 JA |
1692 | if (__cfqq) |
1693 | return __cfqq; | |
1694 | ||
1695 | /* | |
1696 | * If the exact sector wasn't found, the parent of the NULL leaf | |
1697 | * will contain the closest sector. | |
1698 | */ | |
1699 | __cfqq = rb_entry(parent, struct cfq_queue, p_node); | |
e9ce335d | 1700 | if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq)) |
a36e71f9 JA |
1701 | return __cfqq; |
1702 | ||
2e46e8b2 | 1703 | if (blk_rq_pos(__cfqq->next_rq) < sector) |
a36e71f9 JA |
1704 | node = rb_next(&__cfqq->p_node); |
1705 | else | |
1706 | node = rb_prev(&__cfqq->p_node); | |
1707 | if (!node) | |
1708 | return NULL; | |
1709 | ||
1710 | __cfqq = rb_entry(node, struct cfq_queue, p_node); | |
e9ce335d | 1711 | if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq)) |
a36e71f9 JA |
1712 | return __cfqq; |
1713 | ||
1714 | return NULL; | |
1715 | } | |
1716 | ||
1717 | /* | |
1718 | * cfqd - obvious | |
1719 | * cur_cfqq - passed in so that we don't decide that the current queue is | |
1720 | * closely cooperating with itself. | |
1721 | * | |
1722 | * So, basically we're assuming that that cur_cfqq has dispatched at least | |
1723 | * one request, and that cfqd->last_position reflects a position on the disk | |
1724 | * associated with the I/O issued by cur_cfqq. I'm not sure this is a valid | |
1725 | * assumption. | |
1726 | */ | |
1727 | static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd, | |
b3b6d040 | 1728 | struct cfq_queue *cur_cfqq) |
6d048f53 | 1729 | { |
a36e71f9 JA |
1730 | struct cfq_queue *cfqq; |
1731 | ||
39c01b21 DS |
1732 | if (cfq_class_idle(cur_cfqq)) |
1733 | return NULL; | |
e6c5bc73 JM |
1734 | if (!cfq_cfqq_sync(cur_cfqq)) |
1735 | return NULL; | |
1736 | if (CFQQ_SEEKY(cur_cfqq)) | |
1737 | return NULL; | |
1738 | ||
b9d8f4c7 GJ |
1739 | /* |
1740 | * Don't search priority tree if it's the only queue in the group. | |
1741 | */ | |
1742 | if (cur_cfqq->cfqg->nr_cfqq == 1) | |
1743 | return NULL; | |
1744 | ||
6d048f53 | 1745 | /* |
d9e7620e JA |
1746 | * We should notice if some of the queues are cooperating, eg |
1747 | * working closely on the same area of the disk. In that case, | |
1748 | * we can group them together and don't waste time idling. | |
6d048f53 | 1749 | */ |
a36e71f9 JA |
1750 | cfqq = cfqq_close(cfqd, cur_cfqq); |
1751 | if (!cfqq) | |
1752 | return NULL; | |
1753 | ||
8682e1f1 VG |
1754 | /* If new queue belongs to different cfq_group, don't choose it */ |
1755 | if (cur_cfqq->cfqg != cfqq->cfqg) | |
1756 | return NULL; | |
1757 | ||
df5fe3e8 JM |
1758 | /* |
1759 | * It only makes sense to merge sync queues. | |
1760 | */ | |
1761 | if (!cfq_cfqq_sync(cfqq)) | |
1762 | return NULL; | |
e6c5bc73 JM |
1763 | if (CFQQ_SEEKY(cfqq)) |
1764 | return NULL; | |
df5fe3e8 | 1765 | |
c0324a02 CZ |
1766 | /* |
1767 | * Do not merge queues of different priority classes | |
1768 | */ | |
1769 | if (cfq_class_rt(cfqq) != cfq_class_rt(cur_cfqq)) | |
1770 | return NULL; | |
1771 | ||
a36e71f9 | 1772 | return cfqq; |
6d048f53 JA |
1773 | } |
1774 | ||
a6d44e98 CZ |
1775 | /* |
1776 | * Determine whether we should enforce idle window for this queue. | |
1777 | */ | |
1778 | ||
1779 | static bool cfq_should_idle(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1780 | { | |
1781 | enum wl_prio_t prio = cfqq_prio(cfqq); | |
718eee05 | 1782 | struct cfq_rb_root *service_tree = cfqq->service_tree; |
a6d44e98 | 1783 | |
f04a6424 VG |
1784 | BUG_ON(!service_tree); |
1785 | BUG_ON(!service_tree->count); | |
1786 | ||
a6d44e98 CZ |
1787 | /* We never do for idle class queues. */ |
1788 | if (prio == IDLE_WORKLOAD) | |
1789 | return false; | |
1790 | ||
1791 | /* We do for queues that were marked with idle window flag. */ | |
3c764b7a SL |
1792 | if (cfq_cfqq_idle_window(cfqq) && |
1793 | !(blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag)) | |
a6d44e98 CZ |
1794 | return true; |
1795 | ||
1796 | /* | |
1797 | * Otherwise, we do only if they are the last ones | |
1798 | * in their service tree. | |
1799 | */ | |
b1ffe737 DS |
1800 | if (service_tree->count == 1 && cfq_cfqq_sync(cfqq)) |
1801 | return 1; | |
1802 | cfq_log_cfqq(cfqd, cfqq, "Not idling. st->count:%d", | |
1803 | service_tree->count); | |
1804 | return 0; | |
a6d44e98 CZ |
1805 | } |
1806 | ||
6d048f53 | 1807 | static void cfq_arm_slice_timer(struct cfq_data *cfqd) |
22e2c507 | 1808 | { |
1792669c | 1809 | struct cfq_queue *cfqq = cfqd->active_queue; |
206dc69b | 1810 | struct cfq_io_context *cic; |
7b14e3b5 JA |
1811 | unsigned long sl; |
1812 | ||
a68bbddb | 1813 | /* |
f7d7b7a7 JA |
1814 | * SSD device without seek penalty, disable idling. But only do so |
1815 | * for devices that support queuing, otherwise we still have a problem | |
1816 | * with sync vs async workloads. | |
a68bbddb | 1817 | */ |
f7d7b7a7 | 1818 | if (blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag) |
a68bbddb JA |
1819 | return; |
1820 | ||
dd67d051 | 1821 | WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list)); |
6d048f53 | 1822 | WARN_ON(cfq_cfqq_slice_new(cfqq)); |
22e2c507 JA |
1823 | |
1824 | /* | |
1825 | * idle is disabled, either manually or by past process history | |
1826 | */ | |
a6d44e98 | 1827 | if (!cfqd->cfq_slice_idle || !cfq_should_idle(cfqd, cfqq)) |
6d048f53 JA |
1828 | return; |
1829 | ||
7b679138 | 1830 | /* |
8e550632 | 1831 | * still active requests from this queue, don't idle |
7b679138 | 1832 | */ |
8e550632 | 1833 | if (cfqq->dispatched) |
7b679138 JA |
1834 | return; |
1835 | ||
22e2c507 JA |
1836 | /* |
1837 | * task has exited, don't wait | |
1838 | */ | |
206dc69b | 1839 | cic = cfqd->active_cic; |
66dac98e | 1840 | if (!cic || !atomic_read(&cic->ioc->nr_tasks)) |
6d048f53 JA |
1841 | return; |
1842 | ||
355b659c CZ |
1843 | /* |
1844 | * If our average think time is larger than the remaining time | |
1845 | * slice, then don't idle. This avoids overrunning the allotted | |
1846 | * time slice. | |
1847 | */ | |
1848 | if (sample_valid(cic->ttime_samples) && | |
b1ffe737 DS |
1849 | (cfqq->slice_end - jiffies < cic->ttime_mean)) { |
1850 | cfq_log_cfqq(cfqd, cfqq, "Not idling. think_time:%d", | |
1851 | cic->ttime_mean); | |
355b659c | 1852 | return; |
b1ffe737 | 1853 | } |
355b659c | 1854 | |
3b18152c | 1855 | cfq_mark_cfqq_wait_request(cfqq); |
22e2c507 | 1856 | |
6d048f53 | 1857 | sl = cfqd->cfq_slice_idle; |
206dc69b | 1858 | |
7b14e3b5 | 1859 | mod_timer(&cfqd->idle_slice_timer, jiffies + sl); |
9481ffdc | 1860 | cfq_log_cfqq(cfqd, cfqq, "arm_idle: %lu", sl); |
1da177e4 LT |
1861 | } |
1862 | ||
498d3aa2 JA |
1863 | /* |
1864 | * Move request from internal lists to the request queue dispatch list. | |
1865 | */ | |
165125e1 | 1866 | static void cfq_dispatch_insert(struct request_queue *q, struct request *rq) |
1da177e4 | 1867 | { |
3ed9a296 | 1868 | struct cfq_data *cfqd = q->elevator->elevator_data; |
5e705374 | 1869 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 | 1870 | |
7b679138 JA |
1871 | cfq_log_cfqq(cfqd, cfqq, "dispatch_insert"); |
1872 | ||
06d21886 | 1873 | cfqq->next_rq = cfq_find_next_rq(cfqd, cfqq, rq); |
5380a101 | 1874 | cfq_remove_request(rq); |
6d048f53 | 1875 | cfqq->dispatched++; |
5380a101 | 1876 | elv_dispatch_sort(q, rq); |
3ed9a296 | 1877 | |
53c583d2 | 1878 | cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]++; |
22084190 | 1879 | cfqq->nr_sectors += blk_rq_sectors(rq); |
1da177e4 LT |
1880 | } |
1881 | ||
1882 | /* | |
1883 | * return expired entry, or NULL to just start from scratch in rbtree | |
1884 | */ | |
febffd61 | 1885 | static struct request *cfq_check_fifo(struct cfq_queue *cfqq) |
1da177e4 | 1886 | { |
30996f40 | 1887 | struct request *rq = NULL; |
1da177e4 | 1888 | |
3b18152c | 1889 | if (cfq_cfqq_fifo_expire(cfqq)) |
1da177e4 | 1890 | return NULL; |
cb887411 JA |
1891 | |
1892 | cfq_mark_cfqq_fifo_expire(cfqq); | |
1893 | ||
89850f7e JA |
1894 | if (list_empty(&cfqq->fifo)) |
1895 | return NULL; | |
1da177e4 | 1896 | |
89850f7e | 1897 | rq = rq_entry_fifo(cfqq->fifo.next); |
30996f40 | 1898 | if (time_before(jiffies, rq_fifo_time(rq))) |
7b679138 | 1899 | rq = NULL; |
1da177e4 | 1900 | |
30996f40 | 1901 | cfq_log_cfqq(cfqq->cfqd, cfqq, "fifo=%p", rq); |
6d048f53 | 1902 | return rq; |
1da177e4 LT |
1903 | } |
1904 | ||
22e2c507 JA |
1905 | static inline int |
1906 | cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1907 | { | |
1908 | const int base_rq = cfqd->cfq_slice_async_rq; | |
1da177e4 | 1909 | |
22e2c507 | 1910 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); |
1da177e4 | 1911 | |
22e2c507 | 1912 | return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio)); |
1da177e4 LT |
1913 | } |
1914 | ||
df5fe3e8 JM |
1915 | /* |
1916 | * Must be called with the queue_lock held. | |
1917 | */ | |
1918 | static int cfqq_process_refs(struct cfq_queue *cfqq) | |
1919 | { | |
1920 | int process_refs, io_refs; | |
1921 | ||
1922 | io_refs = cfqq->allocated[READ] + cfqq->allocated[WRITE]; | |
1923 | process_refs = atomic_read(&cfqq->ref) - io_refs; | |
1924 | BUG_ON(process_refs < 0); | |
1925 | return process_refs; | |
1926 | } | |
1927 | ||
1928 | static void cfq_setup_merge(struct cfq_queue *cfqq, struct cfq_queue *new_cfqq) | |
1929 | { | |
e6c5bc73 | 1930 | int process_refs, new_process_refs; |
df5fe3e8 JM |
1931 | struct cfq_queue *__cfqq; |
1932 | ||
1933 | /* Avoid a circular list and skip interim queue merges */ | |
1934 | while ((__cfqq = new_cfqq->new_cfqq)) { | |
1935 | if (__cfqq == cfqq) | |
1936 | return; | |
1937 | new_cfqq = __cfqq; | |
1938 | } | |
1939 | ||
1940 | process_refs = cfqq_process_refs(cfqq); | |
1941 | /* | |
1942 | * If the process for the cfqq has gone away, there is no | |
1943 | * sense in merging the queues. | |
1944 | */ | |
1945 | if (process_refs == 0) | |
1946 | return; | |
1947 | ||
e6c5bc73 JM |
1948 | /* |
1949 | * Merge in the direction of the lesser amount of work. | |
1950 | */ | |
1951 | new_process_refs = cfqq_process_refs(new_cfqq); | |
1952 | if (new_process_refs >= process_refs) { | |
1953 | cfqq->new_cfqq = new_cfqq; | |
1954 | atomic_add(process_refs, &new_cfqq->ref); | |
1955 | } else { | |
1956 | new_cfqq->new_cfqq = cfqq; | |
1957 | atomic_add(new_process_refs, &cfqq->ref); | |
1958 | } | |
df5fe3e8 JM |
1959 | } |
1960 | ||
cdb16e8f | 1961 | static enum wl_type_t cfq_choose_wl(struct cfq_data *cfqd, |
65b32a57 | 1962 | struct cfq_group *cfqg, enum wl_prio_t prio) |
718eee05 CZ |
1963 | { |
1964 | struct cfq_queue *queue; | |
1965 | int i; | |
1966 | bool key_valid = false; | |
1967 | unsigned long lowest_key = 0; | |
1968 | enum wl_type_t cur_best = SYNC_NOIDLE_WORKLOAD; | |
1969 | ||
65b32a57 VG |
1970 | for (i = 0; i <= SYNC_WORKLOAD; ++i) { |
1971 | /* select the one with lowest rb_key */ | |
1972 | queue = cfq_rb_first(service_tree_for(cfqg, prio, i)); | |
718eee05 CZ |
1973 | if (queue && |
1974 | (!key_valid || time_before(queue->rb_key, lowest_key))) { | |
1975 | lowest_key = queue->rb_key; | |
1976 | cur_best = i; | |
1977 | key_valid = true; | |
1978 | } | |
1979 | } | |
1980 | ||
1981 | return cur_best; | |
1982 | } | |
1983 | ||
cdb16e8f | 1984 | static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg) |
718eee05 | 1985 | { |
718eee05 CZ |
1986 | unsigned slice; |
1987 | unsigned count; | |
cdb16e8f | 1988 | struct cfq_rb_root *st; |
58ff82f3 | 1989 | unsigned group_slice; |
718eee05 | 1990 | |
1fa8f6d6 VG |
1991 | if (!cfqg) { |
1992 | cfqd->serving_prio = IDLE_WORKLOAD; | |
1993 | cfqd->workload_expires = jiffies + 1; | |
1994 | return; | |
1995 | } | |
1996 | ||
718eee05 | 1997 | /* Choose next priority. RT > BE > IDLE */ |
58ff82f3 | 1998 | if (cfq_group_busy_queues_wl(RT_WORKLOAD, cfqd, cfqg)) |
718eee05 | 1999 | cfqd->serving_prio = RT_WORKLOAD; |
58ff82f3 | 2000 | else if (cfq_group_busy_queues_wl(BE_WORKLOAD, cfqd, cfqg)) |
718eee05 CZ |
2001 | cfqd->serving_prio = BE_WORKLOAD; |
2002 | else { | |
2003 | cfqd->serving_prio = IDLE_WORKLOAD; | |
2004 | cfqd->workload_expires = jiffies + 1; | |
2005 | return; | |
2006 | } | |
2007 | ||
2008 | /* | |
2009 | * For RT and BE, we have to choose also the type | |
2010 | * (SYNC, SYNC_NOIDLE, ASYNC), and to compute a workload | |
2011 | * expiration time | |
2012 | */ | |
65b32a57 | 2013 | st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type); |
cdb16e8f | 2014 | count = st->count; |
718eee05 CZ |
2015 | |
2016 | /* | |
65b32a57 | 2017 | * check workload expiration, and that we still have other queues ready |
718eee05 | 2018 | */ |
65b32a57 | 2019 | if (count && !time_after(jiffies, cfqd->workload_expires)) |
718eee05 CZ |
2020 | return; |
2021 | ||
2022 | /* otherwise select new workload type */ | |
2023 | cfqd->serving_type = | |
65b32a57 VG |
2024 | cfq_choose_wl(cfqd, cfqg, cfqd->serving_prio); |
2025 | st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type); | |
cdb16e8f | 2026 | count = st->count; |
718eee05 CZ |
2027 | |
2028 | /* | |
2029 | * the workload slice is computed as a fraction of target latency | |
2030 | * proportional to the number of queues in that workload, over | |
2031 | * all the queues in the same priority class | |
2032 | */ | |
58ff82f3 VG |
2033 | group_slice = cfq_group_slice(cfqd, cfqg); |
2034 | ||
2035 | slice = group_slice * count / | |
2036 | max_t(unsigned, cfqg->busy_queues_avg[cfqd->serving_prio], | |
2037 | cfq_group_busy_queues_wl(cfqd->serving_prio, cfqd, cfqg)); | |
718eee05 | 2038 | |
f26bd1f0 VG |
2039 | if (cfqd->serving_type == ASYNC_WORKLOAD) { |
2040 | unsigned int tmp; | |
2041 | ||
2042 | /* | |
2043 | * Async queues are currently system wide. Just taking | |
2044 | * proportion of queues with-in same group will lead to higher | |
2045 | * async ratio system wide as generally root group is going | |
2046 | * to have higher weight. A more accurate thing would be to | |
2047 | * calculate system wide asnc/sync ratio. | |
2048 | */ | |
2049 | tmp = cfq_target_latency * cfqg_busy_async_queues(cfqd, cfqg); | |
2050 | tmp = tmp/cfqd->busy_queues; | |
2051 | slice = min_t(unsigned, slice, tmp); | |
2052 | ||
718eee05 CZ |
2053 | /* async workload slice is scaled down according to |
2054 | * the sync/async slice ratio. */ | |
2055 | slice = slice * cfqd->cfq_slice[0] / cfqd->cfq_slice[1]; | |
f26bd1f0 | 2056 | } else |
718eee05 CZ |
2057 | /* sync workload slice is at least 2 * cfq_slice_idle */ |
2058 | slice = max(slice, 2 * cfqd->cfq_slice_idle); | |
2059 | ||
2060 | slice = max_t(unsigned, slice, CFQ_MIN_TT); | |
b1ffe737 | 2061 | cfq_log(cfqd, "workload slice:%d", slice); |
718eee05 | 2062 | cfqd->workload_expires = jiffies + slice; |
8e550632 | 2063 | cfqd->noidle_tree_requires_idle = false; |
718eee05 CZ |
2064 | } |
2065 | ||
1fa8f6d6 VG |
2066 | static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd) |
2067 | { | |
2068 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
25bc6b07 | 2069 | struct cfq_group *cfqg; |
1fa8f6d6 VG |
2070 | |
2071 | if (RB_EMPTY_ROOT(&st->rb)) | |
2072 | return NULL; | |
25bc6b07 VG |
2073 | cfqg = cfq_rb_first_group(st); |
2074 | st->active = &cfqg->rb_node; | |
2075 | update_min_vdisktime(st); | |
2076 | return cfqg; | |
1fa8f6d6 VG |
2077 | } |
2078 | ||
cdb16e8f VG |
2079 | static void cfq_choose_cfqg(struct cfq_data *cfqd) |
2080 | { | |
1fa8f6d6 VG |
2081 | struct cfq_group *cfqg = cfq_get_next_cfqg(cfqd); |
2082 | ||
2083 | cfqd->serving_group = cfqg; | |
dae739eb VG |
2084 | |
2085 | /* Restore the workload type data */ | |
2086 | if (cfqg->saved_workload_slice) { | |
2087 | cfqd->workload_expires = jiffies + cfqg->saved_workload_slice; | |
2088 | cfqd->serving_type = cfqg->saved_workload; | |
2089 | cfqd->serving_prio = cfqg->saved_serving_prio; | |
66ae2919 GJ |
2090 | } else |
2091 | cfqd->workload_expires = jiffies - 1; | |
2092 | ||
1fa8f6d6 | 2093 | choose_service_tree(cfqd, cfqg); |
cdb16e8f VG |
2094 | } |
2095 | ||
22e2c507 | 2096 | /* |
498d3aa2 JA |
2097 | * Select a queue for service. If we have a current active queue, |
2098 | * check whether to continue servicing it, or retrieve and set a new one. | |
22e2c507 | 2099 | */ |
1b5ed5e1 | 2100 | static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) |
1da177e4 | 2101 | { |
a36e71f9 | 2102 | struct cfq_queue *cfqq, *new_cfqq = NULL; |
1da177e4 | 2103 | |
22e2c507 JA |
2104 | cfqq = cfqd->active_queue; |
2105 | if (!cfqq) | |
2106 | goto new_queue; | |
1da177e4 | 2107 | |
f04a6424 VG |
2108 | if (!cfqd->rq_queued) |
2109 | return NULL; | |
c244bb50 VG |
2110 | |
2111 | /* | |
2112 | * We were waiting for group to get backlogged. Expire the queue | |
2113 | */ | |
2114 | if (cfq_cfqq_wait_busy(cfqq) && !RB_EMPTY_ROOT(&cfqq->sort_list)) | |
2115 | goto expire; | |
2116 | ||
22e2c507 | 2117 | /* |
6d048f53 | 2118 | * The active queue has run out of time, expire it and select new. |
22e2c507 | 2119 | */ |
7667aa06 VG |
2120 | if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq)) { |
2121 | /* | |
2122 | * If slice had not expired at the completion of last request | |
2123 | * we might not have turned on wait_busy flag. Don't expire | |
2124 | * the queue yet. Allow the group to get backlogged. | |
2125 | * | |
2126 | * The very fact that we have used the slice, that means we | |
2127 | * have been idling all along on this queue and it should be | |
2128 | * ok to wait for this request to complete. | |
2129 | */ | |
82bbbf28 VG |
2130 | if (cfqq->cfqg->nr_cfqq == 1 && RB_EMPTY_ROOT(&cfqq->sort_list) |
2131 | && cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) { | |
2132 | cfqq = NULL; | |
7667aa06 | 2133 | goto keep_queue; |
82bbbf28 | 2134 | } else |
7667aa06 VG |
2135 | goto expire; |
2136 | } | |
1da177e4 | 2137 | |
22e2c507 | 2138 | /* |
6d048f53 JA |
2139 | * The active queue has requests and isn't expired, allow it to |
2140 | * dispatch. | |
22e2c507 | 2141 | */ |
dd67d051 | 2142 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
22e2c507 | 2143 | goto keep_queue; |
6d048f53 | 2144 | |
a36e71f9 JA |
2145 | /* |
2146 | * If another queue has a request waiting within our mean seek | |
2147 | * distance, let it run. The expire code will check for close | |
2148 | * cooperators and put the close queue at the front of the service | |
df5fe3e8 | 2149 | * tree. If possible, merge the expiring queue with the new cfqq. |
a36e71f9 | 2150 | */ |
b3b6d040 | 2151 | new_cfqq = cfq_close_cooperator(cfqd, cfqq); |
df5fe3e8 JM |
2152 | if (new_cfqq) { |
2153 | if (!cfqq->new_cfqq) | |
2154 | cfq_setup_merge(cfqq, new_cfqq); | |
a36e71f9 | 2155 | goto expire; |
df5fe3e8 | 2156 | } |
a36e71f9 | 2157 | |
6d048f53 JA |
2158 | /* |
2159 | * No requests pending. If the active queue still has requests in | |
2160 | * flight or is idling for a new request, allow either of these | |
2161 | * conditions to happen (or time out) before selecting a new queue. | |
2162 | */ | |
cc197479 | 2163 | if (timer_pending(&cfqd->idle_slice_timer) || |
a6d44e98 | 2164 | (cfqq->dispatched && cfq_should_idle(cfqd, cfqq))) { |
caaa5f9f JA |
2165 | cfqq = NULL; |
2166 | goto keep_queue; | |
22e2c507 JA |
2167 | } |
2168 | ||
3b18152c | 2169 | expire: |
6084cdda | 2170 | cfq_slice_expired(cfqd, 0); |
3b18152c | 2171 | new_queue: |
718eee05 CZ |
2172 | /* |
2173 | * Current queue expired. Check if we have to switch to a new | |
2174 | * service tree | |
2175 | */ | |
2176 | if (!new_cfqq) | |
cdb16e8f | 2177 | cfq_choose_cfqg(cfqd); |
718eee05 | 2178 | |
a36e71f9 | 2179 | cfqq = cfq_set_active_queue(cfqd, new_cfqq); |
22e2c507 | 2180 | keep_queue: |
3b18152c | 2181 | return cfqq; |
22e2c507 JA |
2182 | } |
2183 | ||
febffd61 | 2184 | static int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq) |
d9e7620e JA |
2185 | { |
2186 | int dispatched = 0; | |
2187 | ||
2188 | while (cfqq->next_rq) { | |
2189 | cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq); | |
2190 | dispatched++; | |
2191 | } | |
2192 | ||
2193 | BUG_ON(!list_empty(&cfqq->fifo)); | |
f04a6424 VG |
2194 | |
2195 | /* By default cfqq is not expired if it is empty. Do it explicitly */ | |
2196 | __cfq_slice_expired(cfqq->cfqd, cfqq, 0); | |
d9e7620e JA |
2197 | return dispatched; |
2198 | } | |
2199 | ||
498d3aa2 JA |
2200 | /* |
2201 | * Drain our current requests. Used for barriers and when switching | |
2202 | * io schedulers on-the-fly. | |
2203 | */ | |
d9e7620e | 2204 | static int cfq_forced_dispatch(struct cfq_data *cfqd) |
1b5ed5e1 | 2205 | { |
0871714e | 2206 | struct cfq_queue *cfqq; |
d9e7620e | 2207 | int dispatched = 0; |
cdb16e8f | 2208 | |
3440c49f DS |
2209 | /* Expire the timeslice of the current active queue first */ |
2210 | cfq_slice_expired(cfqd, 0); | |
2211 | while ((cfqq = cfq_get_next_queue_forced(cfqd)) != NULL) { | |
2212 | __cfq_set_active_queue(cfqd, cfqq); | |
f04a6424 | 2213 | dispatched += __cfq_forced_dispatch_cfqq(cfqq); |
3440c49f | 2214 | } |
1b5ed5e1 | 2215 | |
1b5ed5e1 TH |
2216 | BUG_ON(cfqd->busy_queues); |
2217 | ||
6923715a | 2218 | cfq_log(cfqd, "forced_dispatch=%d", dispatched); |
1b5ed5e1 TH |
2219 | return dispatched; |
2220 | } | |
2221 | ||
abc3c744 SL |
2222 | static inline bool cfq_slice_used_soon(struct cfq_data *cfqd, |
2223 | struct cfq_queue *cfqq) | |
2224 | { | |
2225 | /* the queue hasn't finished any request, can't estimate */ | |
2226 | if (cfq_cfqq_slice_new(cfqq)) | |
2227 | return 1; | |
2228 | if (time_after(jiffies + cfqd->cfq_slice_idle * cfqq->dispatched, | |
2229 | cfqq->slice_end)) | |
2230 | return 1; | |
2231 | ||
2232 | return 0; | |
2233 | } | |
2234 | ||
0b182d61 | 2235 | static bool cfq_may_dispatch(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
2f5cb738 | 2236 | { |
2f5cb738 | 2237 | unsigned int max_dispatch; |
22e2c507 | 2238 | |
5ad531db JA |
2239 | /* |
2240 | * Drain async requests before we start sync IO | |
2241 | */ | |
53c583d2 | 2242 | if (cfq_should_idle(cfqd, cfqq) && cfqd->rq_in_flight[BLK_RW_ASYNC]) |
0b182d61 | 2243 | return false; |
5ad531db | 2244 | |
2f5cb738 JA |
2245 | /* |
2246 | * If this is an async queue and we have sync IO in flight, let it wait | |
2247 | */ | |
53c583d2 | 2248 | if (cfqd->rq_in_flight[BLK_RW_SYNC] && !cfq_cfqq_sync(cfqq)) |
0b182d61 | 2249 | return false; |
2f5cb738 | 2250 | |
abc3c744 | 2251 | max_dispatch = max_t(unsigned int, cfqd->cfq_quantum / 2, 1); |
2f5cb738 JA |
2252 | if (cfq_class_idle(cfqq)) |
2253 | max_dispatch = 1; | |
b4878f24 | 2254 | |
2f5cb738 JA |
2255 | /* |
2256 | * Does this cfqq already have too much IO in flight? | |
2257 | */ | |
2258 | if (cfqq->dispatched >= max_dispatch) { | |
2259 | /* | |
2260 | * idle queue must always only have a single IO in flight | |
2261 | */ | |
3ed9a296 | 2262 | if (cfq_class_idle(cfqq)) |
0b182d61 | 2263 | return false; |
3ed9a296 | 2264 | |
2f5cb738 JA |
2265 | /* |
2266 | * We have other queues, don't allow more IO from this one | |
2267 | */ | |
abc3c744 | 2268 | if (cfqd->busy_queues > 1 && cfq_slice_used_soon(cfqd, cfqq)) |
0b182d61 | 2269 | return false; |
9ede209e | 2270 | |
365722bb | 2271 | /* |
474b18cc | 2272 | * Sole queue user, no limit |
365722bb | 2273 | */ |
abc3c744 SL |
2274 | if (cfqd->busy_queues == 1) |
2275 | max_dispatch = -1; | |
2276 | else | |
2277 | /* | |
2278 | * Normally we start throttling cfqq when cfq_quantum/2 | |
2279 | * requests have been dispatched. But we can drive | |
2280 | * deeper queue depths at the beginning of slice | |
2281 | * subjected to upper limit of cfq_quantum. | |
2282 | * */ | |
2283 | max_dispatch = cfqd->cfq_quantum; | |
8e296755 JA |
2284 | } |
2285 | ||
2286 | /* | |
2287 | * Async queues must wait a bit before being allowed dispatch. | |
2288 | * We also ramp up the dispatch depth gradually for async IO, | |
2289 | * based on the last sync IO we serviced | |
2290 | */ | |
963b72fc | 2291 | if (!cfq_cfqq_sync(cfqq) && cfqd->cfq_latency) { |
573412b2 | 2292 | unsigned long last_sync = jiffies - cfqd->last_delayed_sync; |
8e296755 | 2293 | unsigned int depth; |
365722bb | 2294 | |
61f0c1dc | 2295 | depth = last_sync / cfqd->cfq_slice[1]; |
e00c54c3 JA |
2296 | if (!depth && !cfqq->dispatched) |
2297 | depth = 1; | |
8e296755 JA |
2298 | if (depth < max_dispatch) |
2299 | max_dispatch = depth; | |
2f5cb738 | 2300 | } |
3ed9a296 | 2301 | |
0b182d61 JA |
2302 | /* |
2303 | * If we're below the current max, allow a dispatch | |
2304 | */ | |
2305 | return cfqq->dispatched < max_dispatch; | |
2306 | } | |
2307 | ||
2308 | /* | |
2309 | * Dispatch a request from cfqq, moving them to the request queue | |
2310 | * dispatch list. | |
2311 | */ | |
2312 | static bool cfq_dispatch_request(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
2313 | { | |
2314 | struct request *rq; | |
2315 | ||
2316 | BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list)); | |
2317 | ||
2318 | if (!cfq_may_dispatch(cfqd, cfqq)) | |
2319 | return false; | |
2320 | ||
2321 | /* | |
2322 | * follow expired path, else get first next available | |
2323 | */ | |
2324 | rq = cfq_check_fifo(cfqq); | |
2325 | if (!rq) | |
2326 | rq = cfqq->next_rq; | |
2327 | ||
2328 | /* | |
2329 | * insert request into driver dispatch list | |
2330 | */ | |
2331 | cfq_dispatch_insert(cfqd->queue, rq); | |
2332 | ||
2333 | if (!cfqd->active_cic) { | |
2334 | struct cfq_io_context *cic = RQ_CIC(rq); | |
2335 | ||
2336 | atomic_long_inc(&cic->ioc->refcount); | |
2337 | cfqd->active_cic = cic; | |
2338 | } | |
2339 | ||
2340 | return true; | |
2341 | } | |
2342 | ||
2343 | /* | |
2344 | * Find the cfqq that we need to service and move a request from that to the | |
2345 | * dispatch list | |
2346 | */ | |
2347 | static int cfq_dispatch_requests(struct request_queue *q, int force) | |
2348 | { | |
2349 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
2350 | struct cfq_queue *cfqq; | |
2351 | ||
2352 | if (!cfqd->busy_queues) | |
2353 | return 0; | |
2354 | ||
2355 | if (unlikely(force)) | |
2356 | return cfq_forced_dispatch(cfqd); | |
2357 | ||
2358 | cfqq = cfq_select_queue(cfqd); | |
2359 | if (!cfqq) | |
8e296755 JA |
2360 | return 0; |
2361 | ||
2f5cb738 | 2362 | /* |
0b182d61 | 2363 | * Dispatch a request from this cfqq, if it is allowed |
2f5cb738 | 2364 | */ |
0b182d61 JA |
2365 | if (!cfq_dispatch_request(cfqd, cfqq)) |
2366 | return 0; | |
2367 | ||
2f5cb738 | 2368 | cfqq->slice_dispatch++; |
b029195d | 2369 | cfq_clear_cfqq_must_dispatch(cfqq); |
22e2c507 | 2370 | |
2f5cb738 JA |
2371 | /* |
2372 | * expire an async queue immediately if it has used up its slice. idle | |
2373 | * queue always expire after 1 dispatch round. | |
2374 | */ | |
2375 | if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) && | |
2376 | cfqq->slice_dispatch >= cfq_prio_to_maxrq(cfqd, cfqq)) || | |
2377 | cfq_class_idle(cfqq))) { | |
2378 | cfqq->slice_end = jiffies + 1; | |
2379 | cfq_slice_expired(cfqd, 0); | |
1da177e4 LT |
2380 | } |
2381 | ||
b217a903 | 2382 | cfq_log_cfqq(cfqd, cfqq, "dispatched a request"); |
2f5cb738 | 2383 | return 1; |
1da177e4 LT |
2384 | } |
2385 | ||
1da177e4 | 2386 | /* |
5e705374 JA |
2387 | * task holds one reference to the queue, dropped when task exits. each rq |
2388 | * in-flight on this queue also holds a reference, dropped when rq is freed. | |
1da177e4 | 2389 | * |
b1c35769 | 2390 | * Each cfq queue took a reference on the parent group. Drop it now. |
1da177e4 LT |
2391 | * queue lock must be held here. |
2392 | */ | |
2393 | static void cfq_put_queue(struct cfq_queue *cfqq) | |
2394 | { | |
22e2c507 | 2395 | struct cfq_data *cfqd = cfqq->cfqd; |
878eaddd | 2396 | struct cfq_group *cfqg, *orig_cfqg; |
22e2c507 JA |
2397 | |
2398 | BUG_ON(atomic_read(&cfqq->ref) <= 0); | |
1da177e4 LT |
2399 | |
2400 | if (!atomic_dec_and_test(&cfqq->ref)) | |
2401 | return; | |
2402 | ||
7b679138 | 2403 | cfq_log_cfqq(cfqd, cfqq, "put_queue"); |
1da177e4 | 2404 | BUG_ON(rb_first(&cfqq->sort_list)); |
22e2c507 | 2405 | BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]); |
b1c35769 | 2406 | cfqg = cfqq->cfqg; |
878eaddd | 2407 | orig_cfqg = cfqq->orig_cfqg; |
1da177e4 | 2408 | |
28f95cbc | 2409 | if (unlikely(cfqd->active_queue == cfqq)) { |
6084cdda | 2410 | __cfq_slice_expired(cfqd, cfqq, 0); |
23e018a1 | 2411 | cfq_schedule_dispatch(cfqd); |
28f95cbc | 2412 | } |
22e2c507 | 2413 | |
f04a6424 | 2414 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
1da177e4 | 2415 | kmem_cache_free(cfq_pool, cfqq); |
b1c35769 | 2416 | cfq_put_cfqg(cfqg); |
878eaddd VG |
2417 | if (orig_cfqg) |
2418 | cfq_put_cfqg(orig_cfqg); | |
1da177e4 LT |
2419 | } |
2420 | ||
d6de8be7 JA |
2421 | /* |
2422 | * Must always be called with the rcu_read_lock() held | |
2423 | */ | |
07416d29 JA |
2424 | static void |
2425 | __call_for_each_cic(struct io_context *ioc, | |
2426 | void (*func)(struct io_context *, struct cfq_io_context *)) | |
2427 | { | |
2428 | struct cfq_io_context *cic; | |
2429 | struct hlist_node *n; | |
2430 | ||
2431 | hlist_for_each_entry_rcu(cic, n, &ioc->cic_list, cic_list) | |
2432 | func(ioc, cic); | |
2433 | } | |
2434 | ||
4ac845a2 | 2435 | /* |
34e6bbf2 | 2436 | * Call func for each cic attached to this ioc. |
4ac845a2 | 2437 | */ |
34e6bbf2 | 2438 | static void |
4ac845a2 JA |
2439 | call_for_each_cic(struct io_context *ioc, |
2440 | void (*func)(struct io_context *, struct cfq_io_context *)) | |
1da177e4 | 2441 | { |
4ac845a2 | 2442 | rcu_read_lock(); |
07416d29 | 2443 | __call_for_each_cic(ioc, func); |
4ac845a2 | 2444 | rcu_read_unlock(); |
34e6bbf2 FC |
2445 | } |
2446 | ||
2447 | static void cfq_cic_free_rcu(struct rcu_head *head) | |
2448 | { | |
2449 | struct cfq_io_context *cic; | |
2450 | ||
2451 | cic = container_of(head, struct cfq_io_context, rcu_head); | |
2452 | ||
2453 | kmem_cache_free(cfq_ioc_pool, cic); | |
245b2e70 | 2454 | elv_ioc_count_dec(cfq_ioc_count); |
34e6bbf2 | 2455 | |
9a11b4ed JA |
2456 | if (ioc_gone) { |
2457 | /* | |
2458 | * CFQ scheduler is exiting, grab exit lock and check | |
2459 | * the pending io context count. If it hits zero, | |
2460 | * complete ioc_gone and set it back to NULL | |
2461 | */ | |
2462 | spin_lock(&ioc_gone_lock); | |
245b2e70 | 2463 | if (ioc_gone && !elv_ioc_count_read(cfq_ioc_count)) { |
9a11b4ed JA |
2464 | complete(ioc_gone); |
2465 | ioc_gone = NULL; | |
2466 | } | |
2467 | spin_unlock(&ioc_gone_lock); | |
2468 | } | |
34e6bbf2 | 2469 | } |
4ac845a2 | 2470 | |
34e6bbf2 FC |
2471 | static void cfq_cic_free(struct cfq_io_context *cic) |
2472 | { | |
2473 | call_rcu(&cic->rcu_head, cfq_cic_free_rcu); | |
4ac845a2 JA |
2474 | } |
2475 | ||
2476 | static void cic_free_func(struct io_context *ioc, struct cfq_io_context *cic) | |
2477 | { | |
2478 | unsigned long flags; | |
2479 | ||
2480 | BUG_ON(!cic->dead_key); | |
2481 | ||
2482 | spin_lock_irqsave(&ioc->lock, flags); | |
2483 | radix_tree_delete(&ioc->radix_root, cic->dead_key); | |
ffc4e759 | 2484 | hlist_del_rcu(&cic->cic_list); |
4ac845a2 JA |
2485 | spin_unlock_irqrestore(&ioc->lock, flags); |
2486 | ||
34e6bbf2 | 2487 | cfq_cic_free(cic); |
4ac845a2 JA |
2488 | } |
2489 | ||
d6de8be7 JA |
2490 | /* |
2491 | * Must be called with rcu_read_lock() held or preemption otherwise disabled. | |
2492 | * Only two callers of this - ->dtor() which is called with the rcu_read_lock(), | |
2493 | * and ->trim() which is called with the task lock held | |
2494 | */ | |
4ac845a2 JA |
2495 | static void cfq_free_io_context(struct io_context *ioc) |
2496 | { | |
4ac845a2 | 2497 | /* |
34e6bbf2 FC |
2498 | * ioc->refcount is zero here, or we are called from elv_unregister(), |
2499 | * so no more cic's are allowed to be linked into this ioc. So it | |
2500 | * should be ok to iterate over the known list, we will see all cic's | |
2501 | * since no new ones are added. | |
4ac845a2 | 2502 | */ |
07416d29 | 2503 | __call_for_each_cic(ioc, cic_free_func); |
1da177e4 LT |
2504 | } |
2505 | ||
89850f7e | 2506 | static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 2507 | { |
df5fe3e8 JM |
2508 | struct cfq_queue *__cfqq, *next; |
2509 | ||
28f95cbc | 2510 | if (unlikely(cfqq == cfqd->active_queue)) { |
6084cdda | 2511 | __cfq_slice_expired(cfqd, cfqq, 0); |
23e018a1 | 2512 | cfq_schedule_dispatch(cfqd); |
28f95cbc | 2513 | } |
22e2c507 | 2514 | |
df5fe3e8 JM |
2515 | /* |
2516 | * If this queue was scheduled to merge with another queue, be | |
2517 | * sure to drop the reference taken on that queue (and others in | |
2518 | * the merge chain). See cfq_setup_merge and cfq_merge_cfqqs. | |
2519 | */ | |
2520 | __cfqq = cfqq->new_cfqq; | |
2521 | while (__cfqq) { | |
2522 | if (__cfqq == cfqq) { | |
2523 | WARN(1, "cfqq->new_cfqq loop detected\n"); | |
2524 | break; | |
2525 | } | |
2526 | next = __cfqq->new_cfqq; | |
2527 | cfq_put_queue(__cfqq); | |
2528 | __cfqq = next; | |
2529 | } | |
2530 | ||
89850f7e JA |
2531 | cfq_put_queue(cfqq); |
2532 | } | |
22e2c507 | 2533 | |
89850f7e JA |
2534 | static void __cfq_exit_single_io_context(struct cfq_data *cfqd, |
2535 | struct cfq_io_context *cic) | |
2536 | { | |
4faa3c81 FC |
2537 | struct io_context *ioc = cic->ioc; |
2538 | ||
fc46379d | 2539 | list_del_init(&cic->queue_list); |
4ac845a2 JA |
2540 | |
2541 | /* | |
2542 | * Make sure key == NULL is seen for dead queues | |
2543 | */ | |
fc46379d | 2544 | smp_wmb(); |
4ac845a2 | 2545 | cic->dead_key = (unsigned long) cic->key; |
fc46379d JA |
2546 | cic->key = NULL; |
2547 | ||
4faa3c81 FC |
2548 | if (ioc->ioc_data == cic) |
2549 | rcu_assign_pointer(ioc->ioc_data, NULL); | |
2550 | ||
ff6657c6 JA |
2551 | if (cic->cfqq[BLK_RW_ASYNC]) { |
2552 | cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_ASYNC]); | |
2553 | cic->cfqq[BLK_RW_ASYNC] = NULL; | |
12a05732 AV |
2554 | } |
2555 | ||
ff6657c6 JA |
2556 | if (cic->cfqq[BLK_RW_SYNC]) { |
2557 | cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_SYNC]); | |
2558 | cic->cfqq[BLK_RW_SYNC] = NULL; | |
12a05732 | 2559 | } |
89850f7e JA |
2560 | } |
2561 | ||
4ac845a2 JA |
2562 | static void cfq_exit_single_io_context(struct io_context *ioc, |
2563 | struct cfq_io_context *cic) | |
89850f7e JA |
2564 | { |
2565 | struct cfq_data *cfqd = cic->key; | |
2566 | ||
89850f7e | 2567 | if (cfqd) { |
165125e1 | 2568 | struct request_queue *q = cfqd->queue; |
4ac845a2 | 2569 | unsigned long flags; |
89850f7e | 2570 | |
4ac845a2 | 2571 | spin_lock_irqsave(q->queue_lock, flags); |
62c1fe9d JA |
2572 | |
2573 | /* | |
2574 | * Ensure we get a fresh copy of the ->key to prevent | |
2575 | * race between exiting task and queue | |
2576 | */ | |
2577 | smp_read_barrier_depends(); | |
2578 | if (cic->key) | |
2579 | __cfq_exit_single_io_context(cfqd, cic); | |
2580 | ||
4ac845a2 | 2581 | spin_unlock_irqrestore(q->queue_lock, flags); |
89850f7e | 2582 | } |
1da177e4 LT |
2583 | } |
2584 | ||
498d3aa2 JA |
2585 | /* |
2586 | * The process that ioc belongs to has exited, we need to clean up | |
2587 | * and put the internal structures we have that belongs to that process. | |
2588 | */ | |
e2d74ac0 | 2589 | static void cfq_exit_io_context(struct io_context *ioc) |
1da177e4 | 2590 | { |
4ac845a2 | 2591 | call_for_each_cic(ioc, cfq_exit_single_io_context); |
1da177e4 LT |
2592 | } |
2593 | ||
22e2c507 | 2594 | static struct cfq_io_context * |
8267e268 | 2595 | cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
1da177e4 | 2596 | { |
b5deef90 | 2597 | struct cfq_io_context *cic; |
1da177e4 | 2598 | |
94f6030c CL |
2599 | cic = kmem_cache_alloc_node(cfq_ioc_pool, gfp_mask | __GFP_ZERO, |
2600 | cfqd->queue->node); | |
1da177e4 | 2601 | if (cic) { |
22e2c507 | 2602 | cic->last_end_request = jiffies; |
553698f9 | 2603 | INIT_LIST_HEAD(&cic->queue_list); |
ffc4e759 | 2604 | INIT_HLIST_NODE(&cic->cic_list); |
22e2c507 JA |
2605 | cic->dtor = cfq_free_io_context; |
2606 | cic->exit = cfq_exit_io_context; | |
245b2e70 | 2607 | elv_ioc_count_inc(cfq_ioc_count); |
1da177e4 LT |
2608 | } |
2609 | ||
2610 | return cic; | |
2611 | } | |
2612 | ||
fd0928df | 2613 | static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc) |
22e2c507 JA |
2614 | { |
2615 | struct task_struct *tsk = current; | |
2616 | int ioprio_class; | |
2617 | ||
3b18152c | 2618 | if (!cfq_cfqq_prio_changed(cfqq)) |
22e2c507 JA |
2619 | return; |
2620 | ||
fd0928df | 2621 | ioprio_class = IOPRIO_PRIO_CLASS(ioc->ioprio); |
22e2c507 | 2622 | switch (ioprio_class) { |
fe094d98 JA |
2623 | default: |
2624 | printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class); | |
2625 | case IOPRIO_CLASS_NONE: | |
2626 | /* | |
6d63c275 | 2627 | * no prio set, inherit CPU scheduling settings |
fe094d98 JA |
2628 | */ |
2629 | cfqq->ioprio = task_nice_ioprio(tsk); | |
6d63c275 | 2630 | cfqq->ioprio_class = task_nice_ioclass(tsk); |
fe094d98 JA |
2631 | break; |
2632 | case IOPRIO_CLASS_RT: | |
2633 | cfqq->ioprio = task_ioprio(ioc); | |
2634 | cfqq->ioprio_class = IOPRIO_CLASS_RT; | |
2635 | break; | |
2636 | case IOPRIO_CLASS_BE: | |
2637 | cfqq->ioprio = task_ioprio(ioc); | |
2638 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
2639 | break; | |
2640 | case IOPRIO_CLASS_IDLE: | |
2641 | cfqq->ioprio_class = IOPRIO_CLASS_IDLE; | |
2642 | cfqq->ioprio = 7; | |
2643 | cfq_clear_cfqq_idle_window(cfqq); | |
2644 | break; | |
22e2c507 JA |
2645 | } |
2646 | ||
2647 | /* | |
2648 | * keep track of original prio settings in case we have to temporarily | |
2649 | * elevate the priority of this queue | |
2650 | */ | |
2651 | cfqq->org_ioprio = cfqq->ioprio; | |
2652 | cfqq->org_ioprio_class = cfqq->ioprio_class; | |
3b18152c | 2653 | cfq_clear_cfqq_prio_changed(cfqq); |
22e2c507 JA |
2654 | } |
2655 | ||
febffd61 | 2656 | static void changed_ioprio(struct io_context *ioc, struct cfq_io_context *cic) |
22e2c507 | 2657 | { |
478a82b0 AV |
2658 | struct cfq_data *cfqd = cic->key; |
2659 | struct cfq_queue *cfqq; | |
c1b707d2 | 2660 | unsigned long flags; |
35e6077c | 2661 | |
caaa5f9f JA |
2662 | if (unlikely(!cfqd)) |
2663 | return; | |
2664 | ||
c1b707d2 | 2665 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); |
caaa5f9f | 2666 | |
ff6657c6 | 2667 | cfqq = cic->cfqq[BLK_RW_ASYNC]; |
caaa5f9f JA |
2668 | if (cfqq) { |
2669 | struct cfq_queue *new_cfqq; | |
ff6657c6 JA |
2670 | new_cfqq = cfq_get_queue(cfqd, BLK_RW_ASYNC, cic->ioc, |
2671 | GFP_ATOMIC); | |
caaa5f9f | 2672 | if (new_cfqq) { |
ff6657c6 | 2673 | cic->cfqq[BLK_RW_ASYNC] = new_cfqq; |
caaa5f9f JA |
2674 | cfq_put_queue(cfqq); |
2675 | } | |
22e2c507 | 2676 | } |
caaa5f9f | 2677 | |
ff6657c6 | 2678 | cfqq = cic->cfqq[BLK_RW_SYNC]; |
caaa5f9f JA |
2679 | if (cfqq) |
2680 | cfq_mark_cfqq_prio_changed(cfqq); | |
2681 | ||
c1b707d2 | 2682 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); |
22e2c507 JA |
2683 | } |
2684 | ||
fc46379d | 2685 | static void cfq_ioc_set_ioprio(struct io_context *ioc) |
22e2c507 | 2686 | { |
4ac845a2 | 2687 | call_for_each_cic(ioc, changed_ioprio); |
fc46379d | 2688 | ioc->ioprio_changed = 0; |
22e2c507 JA |
2689 | } |
2690 | ||
d5036d77 | 2691 | static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
a6151c3a | 2692 | pid_t pid, bool is_sync) |
d5036d77 JA |
2693 | { |
2694 | RB_CLEAR_NODE(&cfqq->rb_node); | |
2695 | RB_CLEAR_NODE(&cfqq->p_node); | |
2696 | INIT_LIST_HEAD(&cfqq->fifo); | |
2697 | ||
2698 | atomic_set(&cfqq->ref, 0); | |
2699 | cfqq->cfqd = cfqd; | |
2700 | ||
2701 | cfq_mark_cfqq_prio_changed(cfqq); | |
2702 | ||
2703 | if (is_sync) { | |
2704 | if (!cfq_class_idle(cfqq)) | |
2705 | cfq_mark_cfqq_idle_window(cfqq); | |
2706 | cfq_mark_cfqq_sync(cfqq); | |
2707 | } | |
2708 | cfqq->pid = pid; | |
2709 | } | |
2710 | ||
24610333 VG |
2711 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
2712 | static void changed_cgroup(struct io_context *ioc, struct cfq_io_context *cic) | |
2713 | { | |
2714 | struct cfq_queue *sync_cfqq = cic_to_cfqq(cic, 1); | |
2715 | struct cfq_data *cfqd = cic->key; | |
2716 | unsigned long flags; | |
2717 | struct request_queue *q; | |
2718 | ||
2719 | if (unlikely(!cfqd)) | |
2720 | return; | |
2721 | ||
2722 | q = cfqd->queue; | |
2723 | ||
2724 | spin_lock_irqsave(q->queue_lock, flags); | |
2725 | ||
2726 | if (sync_cfqq) { | |
2727 | /* | |
2728 | * Drop reference to sync queue. A new sync queue will be | |
2729 | * assigned in new group upon arrival of a fresh request. | |
2730 | */ | |
2731 | cfq_log_cfqq(cfqd, sync_cfqq, "changed cgroup"); | |
2732 | cic_set_cfqq(cic, NULL, 1); | |
2733 | cfq_put_queue(sync_cfqq); | |
2734 | } | |
2735 | ||
2736 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2737 | } | |
2738 | ||
2739 | static void cfq_ioc_set_cgroup(struct io_context *ioc) | |
2740 | { | |
2741 | call_for_each_cic(ioc, changed_cgroup); | |
2742 | ioc->cgroup_changed = 0; | |
2743 | } | |
2744 | #endif /* CONFIG_CFQ_GROUP_IOSCHED */ | |
2745 | ||
22e2c507 | 2746 | static struct cfq_queue * |
a6151c3a | 2747 | cfq_find_alloc_queue(struct cfq_data *cfqd, bool is_sync, |
fd0928df | 2748 | struct io_context *ioc, gfp_t gfp_mask) |
22e2c507 | 2749 | { |
22e2c507 | 2750 | struct cfq_queue *cfqq, *new_cfqq = NULL; |
91fac317 | 2751 | struct cfq_io_context *cic; |
cdb16e8f | 2752 | struct cfq_group *cfqg; |
22e2c507 JA |
2753 | |
2754 | retry: | |
cdb16e8f | 2755 | cfqg = cfq_get_cfqg(cfqd, 1); |
4ac845a2 | 2756 | cic = cfq_cic_lookup(cfqd, ioc); |
91fac317 VT |
2757 | /* cic always exists here */ |
2758 | cfqq = cic_to_cfqq(cic, is_sync); | |
22e2c507 | 2759 | |
6118b70b JA |
2760 | /* |
2761 | * Always try a new alloc if we fell back to the OOM cfqq | |
2762 | * originally, since it should just be a temporary situation. | |
2763 | */ | |
2764 | if (!cfqq || cfqq == &cfqd->oom_cfqq) { | |
2765 | cfqq = NULL; | |
22e2c507 JA |
2766 | if (new_cfqq) { |
2767 | cfqq = new_cfqq; | |
2768 | new_cfqq = NULL; | |
2769 | } else if (gfp_mask & __GFP_WAIT) { | |
2770 | spin_unlock_irq(cfqd->queue->queue_lock); | |
94f6030c | 2771 | new_cfqq = kmem_cache_alloc_node(cfq_pool, |
6118b70b | 2772 | gfp_mask | __GFP_ZERO, |
94f6030c | 2773 | cfqd->queue->node); |
22e2c507 | 2774 | spin_lock_irq(cfqd->queue->queue_lock); |
6118b70b JA |
2775 | if (new_cfqq) |
2776 | goto retry; | |
22e2c507 | 2777 | } else { |
94f6030c CL |
2778 | cfqq = kmem_cache_alloc_node(cfq_pool, |
2779 | gfp_mask | __GFP_ZERO, | |
2780 | cfqd->queue->node); | |
22e2c507 JA |
2781 | } |
2782 | ||
6118b70b JA |
2783 | if (cfqq) { |
2784 | cfq_init_cfqq(cfqd, cfqq, current->pid, is_sync); | |
2785 | cfq_init_prio_data(cfqq, ioc); | |
cdb16e8f | 2786 | cfq_link_cfqq_cfqg(cfqq, cfqg); |
6118b70b JA |
2787 | cfq_log_cfqq(cfqd, cfqq, "alloced"); |
2788 | } else | |
2789 | cfqq = &cfqd->oom_cfqq; | |
22e2c507 JA |
2790 | } |
2791 | ||
2792 | if (new_cfqq) | |
2793 | kmem_cache_free(cfq_pool, new_cfqq); | |
2794 | ||
22e2c507 JA |
2795 | return cfqq; |
2796 | } | |
2797 | ||
c2dea2d1 VT |
2798 | static struct cfq_queue ** |
2799 | cfq_async_queue_prio(struct cfq_data *cfqd, int ioprio_class, int ioprio) | |
2800 | { | |
fe094d98 | 2801 | switch (ioprio_class) { |
c2dea2d1 VT |
2802 | case IOPRIO_CLASS_RT: |
2803 | return &cfqd->async_cfqq[0][ioprio]; | |
2804 | case IOPRIO_CLASS_BE: | |
2805 | return &cfqd->async_cfqq[1][ioprio]; | |
2806 | case IOPRIO_CLASS_IDLE: | |
2807 | return &cfqd->async_idle_cfqq; | |
2808 | default: | |
2809 | BUG(); | |
2810 | } | |
2811 | } | |
2812 | ||
15c31be4 | 2813 | static struct cfq_queue * |
a6151c3a | 2814 | cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct io_context *ioc, |
15c31be4 JA |
2815 | gfp_t gfp_mask) |
2816 | { | |
fd0928df JA |
2817 | const int ioprio = task_ioprio(ioc); |
2818 | const int ioprio_class = task_ioprio_class(ioc); | |
c2dea2d1 | 2819 | struct cfq_queue **async_cfqq = NULL; |
15c31be4 JA |
2820 | struct cfq_queue *cfqq = NULL; |
2821 | ||
c2dea2d1 VT |
2822 | if (!is_sync) { |
2823 | async_cfqq = cfq_async_queue_prio(cfqd, ioprio_class, ioprio); | |
2824 | cfqq = *async_cfqq; | |
2825 | } | |
2826 | ||
6118b70b | 2827 | if (!cfqq) |
fd0928df | 2828 | cfqq = cfq_find_alloc_queue(cfqd, is_sync, ioc, gfp_mask); |
15c31be4 JA |
2829 | |
2830 | /* | |
2831 | * pin the queue now that it's allocated, scheduler exit will prune it | |
2832 | */ | |
c2dea2d1 | 2833 | if (!is_sync && !(*async_cfqq)) { |
15c31be4 | 2834 | atomic_inc(&cfqq->ref); |
c2dea2d1 | 2835 | *async_cfqq = cfqq; |
15c31be4 JA |
2836 | } |
2837 | ||
2838 | atomic_inc(&cfqq->ref); | |
2839 | return cfqq; | |
2840 | } | |
2841 | ||
498d3aa2 JA |
2842 | /* |
2843 | * We drop cfq io contexts lazily, so we may find a dead one. | |
2844 | */ | |
dbecf3ab | 2845 | static void |
4ac845a2 JA |
2846 | cfq_drop_dead_cic(struct cfq_data *cfqd, struct io_context *ioc, |
2847 | struct cfq_io_context *cic) | |
dbecf3ab | 2848 | { |
4ac845a2 JA |
2849 | unsigned long flags; |
2850 | ||
fc46379d | 2851 | WARN_ON(!list_empty(&cic->queue_list)); |
597bc485 | 2852 | |
4ac845a2 JA |
2853 | spin_lock_irqsave(&ioc->lock, flags); |
2854 | ||
4faa3c81 | 2855 | BUG_ON(ioc->ioc_data == cic); |
597bc485 | 2856 | |
4ac845a2 | 2857 | radix_tree_delete(&ioc->radix_root, (unsigned long) cfqd); |
ffc4e759 | 2858 | hlist_del_rcu(&cic->cic_list); |
4ac845a2 JA |
2859 | spin_unlock_irqrestore(&ioc->lock, flags); |
2860 | ||
2861 | cfq_cic_free(cic); | |
dbecf3ab OH |
2862 | } |
2863 | ||
e2d74ac0 | 2864 | static struct cfq_io_context * |
4ac845a2 | 2865 | cfq_cic_lookup(struct cfq_data *cfqd, struct io_context *ioc) |
e2d74ac0 | 2866 | { |
e2d74ac0 | 2867 | struct cfq_io_context *cic; |
d6de8be7 | 2868 | unsigned long flags; |
4ac845a2 | 2869 | void *k; |
e2d74ac0 | 2870 | |
91fac317 VT |
2871 | if (unlikely(!ioc)) |
2872 | return NULL; | |
2873 | ||
d6de8be7 JA |
2874 | rcu_read_lock(); |
2875 | ||
597bc485 JA |
2876 | /* |
2877 | * we maintain a last-hit cache, to avoid browsing over the tree | |
2878 | */ | |
4ac845a2 | 2879 | cic = rcu_dereference(ioc->ioc_data); |
d6de8be7 JA |
2880 | if (cic && cic->key == cfqd) { |
2881 | rcu_read_unlock(); | |
597bc485 | 2882 | return cic; |
d6de8be7 | 2883 | } |
597bc485 | 2884 | |
4ac845a2 | 2885 | do { |
4ac845a2 JA |
2886 | cic = radix_tree_lookup(&ioc->radix_root, (unsigned long) cfqd); |
2887 | rcu_read_unlock(); | |
2888 | if (!cic) | |
2889 | break; | |
be3b0753 OH |
2890 | /* ->key must be copied to avoid race with cfq_exit_queue() */ |
2891 | k = cic->key; | |
2892 | if (unlikely(!k)) { | |
4ac845a2 | 2893 | cfq_drop_dead_cic(cfqd, ioc, cic); |
d6de8be7 | 2894 | rcu_read_lock(); |
4ac845a2 | 2895 | continue; |
dbecf3ab | 2896 | } |
e2d74ac0 | 2897 | |
d6de8be7 | 2898 | spin_lock_irqsave(&ioc->lock, flags); |
4ac845a2 | 2899 | rcu_assign_pointer(ioc->ioc_data, cic); |
d6de8be7 | 2900 | spin_unlock_irqrestore(&ioc->lock, flags); |
4ac845a2 JA |
2901 | break; |
2902 | } while (1); | |
e2d74ac0 | 2903 | |
4ac845a2 | 2904 | return cic; |
e2d74ac0 JA |
2905 | } |
2906 | ||
4ac845a2 JA |
2907 | /* |
2908 | * Add cic into ioc, using cfqd as the search key. This enables us to lookup | |
2909 | * the process specific cfq io context when entered from the block layer. | |
2910 | * Also adds the cic to a per-cfqd list, used when this queue is removed. | |
2911 | */ | |
febffd61 JA |
2912 | static int cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc, |
2913 | struct cfq_io_context *cic, gfp_t gfp_mask) | |
e2d74ac0 | 2914 | { |
0261d688 | 2915 | unsigned long flags; |
4ac845a2 | 2916 | int ret; |
e2d74ac0 | 2917 | |
4ac845a2 JA |
2918 | ret = radix_tree_preload(gfp_mask); |
2919 | if (!ret) { | |
2920 | cic->ioc = ioc; | |
2921 | cic->key = cfqd; | |
e2d74ac0 | 2922 | |
4ac845a2 JA |
2923 | spin_lock_irqsave(&ioc->lock, flags); |
2924 | ret = radix_tree_insert(&ioc->radix_root, | |
2925 | (unsigned long) cfqd, cic); | |
ffc4e759 JA |
2926 | if (!ret) |
2927 | hlist_add_head_rcu(&cic->cic_list, &ioc->cic_list); | |
4ac845a2 | 2928 | spin_unlock_irqrestore(&ioc->lock, flags); |
e2d74ac0 | 2929 | |
4ac845a2 JA |
2930 | radix_tree_preload_end(); |
2931 | ||
2932 | if (!ret) { | |
2933 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
2934 | list_add(&cic->queue_list, &cfqd->cic_list); | |
2935 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
2936 | } | |
e2d74ac0 JA |
2937 | } |
2938 | ||
4ac845a2 JA |
2939 | if (ret) |
2940 | printk(KERN_ERR "cfq: cic link failed!\n"); | |
fc46379d | 2941 | |
4ac845a2 | 2942 | return ret; |
e2d74ac0 JA |
2943 | } |
2944 | ||
1da177e4 LT |
2945 | /* |
2946 | * Setup general io context and cfq io context. There can be several cfq | |
2947 | * io contexts per general io context, if this process is doing io to more | |
e2d74ac0 | 2948 | * than one device managed by cfq. |
1da177e4 LT |
2949 | */ |
2950 | static struct cfq_io_context * | |
e2d74ac0 | 2951 | cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
1da177e4 | 2952 | { |
22e2c507 | 2953 | struct io_context *ioc = NULL; |
1da177e4 | 2954 | struct cfq_io_context *cic; |
1da177e4 | 2955 | |
22e2c507 | 2956 | might_sleep_if(gfp_mask & __GFP_WAIT); |
1da177e4 | 2957 | |
b5deef90 | 2958 | ioc = get_io_context(gfp_mask, cfqd->queue->node); |
1da177e4 LT |
2959 | if (!ioc) |
2960 | return NULL; | |
2961 | ||
4ac845a2 | 2962 | cic = cfq_cic_lookup(cfqd, ioc); |
e2d74ac0 JA |
2963 | if (cic) |
2964 | goto out; | |
1da177e4 | 2965 | |
e2d74ac0 JA |
2966 | cic = cfq_alloc_io_context(cfqd, gfp_mask); |
2967 | if (cic == NULL) | |
2968 | goto err; | |
1da177e4 | 2969 | |
4ac845a2 JA |
2970 | if (cfq_cic_link(cfqd, ioc, cic, gfp_mask)) |
2971 | goto err_free; | |
2972 | ||
1da177e4 | 2973 | out: |
fc46379d JA |
2974 | smp_read_barrier_depends(); |
2975 | if (unlikely(ioc->ioprio_changed)) | |
2976 | cfq_ioc_set_ioprio(ioc); | |
2977 | ||
24610333 VG |
2978 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
2979 | if (unlikely(ioc->cgroup_changed)) | |
2980 | cfq_ioc_set_cgroup(ioc); | |
2981 | #endif | |
1da177e4 | 2982 | return cic; |
4ac845a2 JA |
2983 | err_free: |
2984 | cfq_cic_free(cic); | |
1da177e4 LT |
2985 | err: |
2986 | put_io_context(ioc); | |
2987 | return NULL; | |
2988 | } | |
2989 | ||
22e2c507 JA |
2990 | static void |
2991 | cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic) | |
1da177e4 | 2992 | { |
aaf1228d JA |
2993 | unsigned long elapsed = jiffies - cic->last_end_request; |
2994 | unsigned long ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle); | |
db3b5848 | 2995 | |
22e2c507 JA |
2996 | cic->ttime_samples = (7*cic->ttime_samples + 256) / 8; |
2997 | cic->ttime_total = (7*cic->ttime_total + 256*ttime) / 8; | |
2998 | cic->ttime_mean = (cic->ttime_total + 128) / cic->ttime_samples; | |
2999 | } | |
1da177e4 | 3000 | |
206dc69b | 3001 | static void |
b2c18e1e | 3002 | cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
6d048f53 | 3003 | struct request *rq) |
206dc69b | 3004 | { |
3dde36dd | 3005 | sector_t sdist = 0; |
41647e7a | 3006 | sector_t n_sec = blk_rq_sectors(rq); |
3dde36dd CZ |
3007 | if (cfqq->last_request_pos) { |
3008 | if (cfqq->last_request_pos < blk_rq_pos(rq)) | |
3009 | sdist = blk_rq_pos(rq) - cfqq->last_request_pos; | |
3010 | else | |
3011 | sdist = cfqq->last_request_pos - blk_rq_pos(rq); | |
3012 | } | |
206dc69b | 3013 | |
3dde36dd | 3014 | cfqq->seek_history <<= 1; |
41647e7a CZ |
3015 | if (blk_queue_nonrot(cfqd->queue)) |
3016 | cfqq->seek_history |= (n_sec < CFQQ_SECT_THR_NONROT); | |
3017 | else | |
3018 | cfqq->seek_history |= (sdist > CFQQ_SEEK_THR); | |
206dc69b | 3019 | } |
1da177e4 | 3020 | |
22e2c507 JA |
3021 | /* |
3022 | * Disable idle window if the process thinks too long or seeks so much that | |
3023 | * it doesn't matter | |
3024 | */ | |
3025 | static void | |
3026 | cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
3027 | struct cfq_io_context *cic) | |
3028 | { | |
7b679138 | 3029 | int old_idle, enable_idle; |
1be92f2f | 3030 | |
0871714e JA |
3031 | /* |
3032 | * Don't idle for async or idle io prio class | |
3033 | */ | |
3034 | if (!cfq_cfqq_sync(cfqq) || cfq_class_idle(cfqq)) | |
1be92f2f JA |
3035 | return; |
3036 | ||
c265a7f4 | 3037 | enable_idle = old_idle = cfq_cfqq_idle_window(cfqq); |
1da177e4 | 3038 | |
76280aff CZ |
3039 | if (cfqq->queued[0] + cfqq->queued[1] >= 4) |
3040 | cfq_mark_cfqq_deep(cfqq); | |
3041 | ||
66dac98e | 3042 | if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle || |
3dde36dd | 3043 | (!cfq_cfqq_deep(cfqq) && CFQQ_SEEKY(cfqq))) |
22e2c507 JA |
3044 | enable_idle = 0; |
3045 | else if (sample_valid(cic->ttime_samples)) { | |
718eee05 | 3046 | if (cic->ttime_mean > cfqd->cfq_slice_idle) |
22e2c507 JA |
3047 | enable_idle = 0; |
3048 | else | |
3049 | enable_idle = 1; | |
1da177e4 LT |
3050 | } |
3051 | ||
7b679138 JA |
3052 | if (old_idle != enable_idle) { |
3053 | cfq_log_cfqq(cfqd, cfqq, "idle=%d", enable_idle); | |
3054 | if (enable_idle) | |
3055 | cfq_mark_cfqq_idle_window(cfqq); | |
3056 | else | |
3057 | cfq_clear_cfqq_idle_window(cfqq); | |
3058 | } | |
22e2c507 | 3059 | } |
1da177e4 | 3060 | |
22e2c507 JA |
3061 | /* |
3062 | * Check if new_cfqq should preempt the currently active queue. Return 0 for | |
3063 | * no or if we aren't sure, a 1 will cause a preempt. | |
3064 | */ | |
a6151c3a | 3065 | static bool |
22e2c507 | 3066 | cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, |
5e705374 | 3067 | struct request *rq) |
22e2c507 | 3068 | { |
6d048f53 | 3069 | struct cfq_queue *cfqq; |
22e2c507 | 3070 | |
6d048f53 JA |
3071 | cfqq = cfqd->active_queue; |
3072 | if (!cfqq) | |
a6151c3a | 3073 | return false; |
22e2c507 | 3074 | |
6d048f53 | 3075 | if (cfq_class_idle(new_cfqq)) |
a6151c3a | 3076 | return false; |
22e2c507 JA |
3077 | |
3078 | if (cfq_class_idle(cfqq)) | |
a6151c3a | 3079 | return true; |
1e3335de | 3080 | |
875feb63 DS |
3081 | /* |
3082 | * Don't allow a non-RT request to preempt an ongoing RT cfqq timeslice. | |
3083 | */ | |
3084 | if (cfq_class_rt(cfqq) && !cfq_class_rt(new_cfqq)) | |
3085 | return false; | |
3086 | ||
374f84ac JA |
3087 | /* |
3088 | * if the new request is sync, but the currently running queue is | |
3089 | * not, let the sync request have priority. | |
3090 | */ | |
5e705374 | 3091 | if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq)) |
a6151c3a | 3092 | return true; |
1e3335de | 3093 | |
8682e1f1 VG |
3094 | if (new_cfqq->cfqg != cfqq->cfqg) |
3095 | return false; | |
3096 | ||
3097 | if (cfq_slice_used(cfqq)) | |
3098 | return true; | |
3099 | ||
3100 | /* Allow preemption only if we are idling on sync-noidle tree */ | |
3101 | if (cfqd->serving_type == SYNC_NOIDLE_WORKLOAD && | |
3102 | cfqq_type(new_cfqq) == SYNC_NOIDLE_WORKLOAD && | |
3103 | new_cfqq->service_tree->count == 2 && | |
3104 | RB_EMPTY_ROOT(&cfqq->sort_list)) | |
3105 | return true; | |
3106 | ||
374f84ac JA |
3107 | /* |
3108 | * So both queues are sync. Let the new request get disk time if | |
3109 | * it's a metadata request and the current queue is doing regular IO. | |
3110 | */ | |
3111 | if (rq_is_meta(rq) && !cfqq->meta_pending) | |
e6ec4fe2 | 3112 | return true; |
22e2c507 | 3113 | |
3a9a3f6c DS |
3114 | /* |
3115 | * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice. | |
3116 | */ | |
3117 | if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq)) | |
a6151c3a | 3118 | return true; |
3a9a3f6c | 3119 | |
1e3335de | 3120 | if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq)) |
a6151c3a | 3121 | return false; |
1e3335de JA |
3122 | |
3123 | /* | |
3124 | * if this request is as-good as one we would expect from the | |
3125 | * current cfqq, let it preempt | |
3126 | */ | |
e9ce335d | 3127 | if (cfq_rq_close(cfqd, cfqq, rq)) |
a6151c3a | 3128 | return true; |
1e3335de | 3129 | |
a6151c3a | 3130 | return false; |
22e2c507 JA |
3131 | } |
3132 | ||
3133 | /* | |
3134 | * cfqq preempts the active queue. if we allowed preempt with no slice left, | |
3135 | * let it have half of its nominal slice. | |
3136 | */ | |
3137 | static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
3138 | { | |
7b679138 | 3139 | cfq_log_cfqq(cfqd, cfqq, "preempt"); |
6084cdda | 3140 | cfq_slice_expired(cfqd, 1); |
22e2c507 | 3141 | |
bf572256 JA |
3142 | /* |
3143 | * Put the new queue at the front of the of the current list, | |
3144 | * so we know that it will be selected next. | |
3145 | */ | |
3146 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); | |
edd75ffd JA |
3147 | |
3148 | cfq_service_tree_add(cfqd, cfqq, 1); | |
bf572256 | 3149 | |
44f7c160 JA |
3150 | cfqq->slice_end = 0; |
3151 | cfq_mark_cfqq_slice_new(cfqq); | |
22e2c507 JA |
3152 | } |
3153 | ||
22e2c507 | 3154 | /* |
5e705374 | 3155 | * Called when a new fs request (rq) is added (to cfqq). Check if there's |
22e2c507 JA |
3156 | * something we should do about it |
3157 | */ | |
3158 | static void | |
5e705374 JA |
3159 | cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
3160 | struct request *rq) | |
22e2c507 | 3161 | { |
5e705374 | 3162 | struct cfq_io_context *cic = RQ_CIC(rq); |
12e9fddd | 3163 | |
45333d5a | 3164 | cfqd->rq_queued++; |
374f84ac JA |
3165 | if (rq_is_meta(rq)) |
3166 | cfqq->meta_pending++; | |
3167 | ||
9c2c38a1 | 3168 | cfq_update_io_thinktime(cfqd, cic); |
b2c18e1e | 3169 | cfq_update_io_seektime(cfqd, cfqq, rq); |
9c2c38a1 JA |
3170 | cfq_update_idle_window(cfqd, cfqq, cic); |
3171 | ||
b2c18e1e | 3172 | cfqq->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq); |
22e2c507 JA |
3173 | |
3174 | if (cfqq == cfqd->active_queue) { | |
3175 | /* | |
b029195d JA |
3176 | * Remember that we saw a request from this process, but |
3177 | * don't start queuing just yet. Otherwise we risk seeing lots | |
3178 | * of tiny requests, because we disrupt the normal plugging | |
d6ceb25e JA |
3179 | * and merging. If the request is already larger than a single |
3180 | * page, let it rip immediately. For that case we assume that | |
2d870722 JA |
3181 | * merging is already done. Ditto for a busy system that |
3182 | * has other work pending, don't risk delaying until the | |
3183 | * idle timer unplug to continue working. | |
22e2c507 | 3184 | */ |
d6ceb25e | 3185 | if (cfq_cfqq_wait_request(cfqq)) { |
2d870722 JA |
3186 | if (blk_rq_bytes(rq) > PAGE_CACHE_SIZE || |
3187 | cfqd->busy_queues > 1) { | |
d6ceb25e | 3188 | del_timer(&cfqd->idle_slice_timer); |
554554f6 | 3189 | cfq_clear_cfqq_wait_request(cfqq); |
bf791937 VG |
3190 | __blk_run_queue(cfqd->queue); |
3191 | } else | |
3192 | cfq_mark_cfqq_must_dispatch(cfqq); | |
d6ceb25e | 3193 | } |
5e705374 | 3194 | } else if (cfq_should_preempt(cfqd, cfqq, rq)) { |
22e2c507 JA |
3195 | /* |
3196 | * not the active queue - expire current slice if it is | |
3197 | * idle and has expired it's mean thinktime or this new queue | |
3a9a3f6c DS |
3198 | * has some old slice time left and is of higher priority or |
3199 | * this new queue is RT and the current one is BE | |
22e2c507 JA |
3200 | */ |
3201 | cfq_preempt_queue(cfqd, cfqq); | |
a7f55792 | 3202 | __blk_run_queue(cfqd->queue); |
22e2c507 | 3203 | } |
1da177e4 LT |
3204 | } |
3205 | ||
165125e1 | 3206 | static void cfq_insert_request(struct request_queue *q, struct request *rq) |
1da177e4 | 3207 | { |
b4878f24 | 3208 | struct cfq_data *cfqd = q->elevator->elevator_data; |
5e705374 | 3209 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 | 3210 | |
7b679138 | 3211 | cfq_log_cfqq(cfqd, cfqq, "insert_request"); |
fd0928df | 3212 | cfq_init_prio_data(cfqq, RQ_CIC(rq)->ioc); |
1da177e4 | 3213 | |
30996f40 | 3214 | rq_set_fifo_time(rq, jiffies + cfqd->cfq_fifo_expire[rq_is_sync(rq)]); |
22e2c507 | 3215 | list_add_tail(&rq->queuelist, &cfqq->fifo); |
aa6f6a3d | 3216 | cfq_add_rq_rb(rq); |
22e2c507 | 3217 | |
5e705374 | 3218 | cfq_rq_enqueued(cfqd, cfqq, rq); |
1da177e4 LT |
3219 | } |
3220 | ||
45333d5a AC |
3221 | /* |
3222 | * Update hw_tag based on peak queue depth over 50 samples under | |
3223 | * sufficient load. | |
3224 | */ | |
3225 | static void cfq_update_hw_tag(struct cfq_data *cfqd) | |
3226 | { | |
1a1238a7 SL |
3227 | struct cfq_queue *cfqq = cfqd->active_queue; |
3228 | ||
53c583d2 CZ |
3229 | if (cfqd->rq_in_driver > cfqd->hw_tag_est_depth) |
3230 | cfqd->hw_tag_est_depth = cfqd->rq_in_driver; | |
e459dd08 CZ |
3231 | |
3232 | if (cfqd->hw_tag == 1) | |
3233 | return; | |
45333d5a AC |
3234 | |
3235 | if (cfqd->rq_queued <= CFQ_HW_QUEUE_MIN && | |
53c583d2 | 3236 | cfqd->rq_in_driver <= CFQ_HW_QUEUE_MIN) |
45333d5a AC |
3237 | return; |
3238 | ||
1a1238a7 SL |
3239 | /* |
3240 | * If active queue hasn't enough requests and can idle, cfq might not | |
3241 | * dispatch sufficient requests to hardware. Don't zero hw_tag in this | |
3242 | * case | |
3243 | */ | |
3244 | if (cfqq && cfq_cfqq_idle_window(cfqq) && | |
3245 | cfqq->dispatched + cfqq->queued[0] + cfqq->queued[1] < | |
53c583d2 | 3246 | CFQ_HW_QUEUE_MIN && cfqd->rq_in_driver < CFQ_HW_QUEUE_MIN) |
1a1238a7 SL |
3247 | return; |
3248 | ||
45333d5a AC |
3249 | if (cfqd->hw_tag_samples++ < 50) |
3250 | return; | |
3251 | ||
e459dd08 | 3252 | if (cfqd->hw_tag_est_depth >= CFQ_HW_QUEUE_MIN) |
45333d5a AC |
3253 | cfqd->hw_tag = 1; |
3254 | else | |
3255 | cfqd->hw_tag = 0; | |
45333d5a AC |
3256 | } |
3257 | ||
7667aa06 VG |
3258 | static bool cfq_should_wait_busy(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
3259 | { | |
3260 | struct cfq_io_context *cic = cfqd->active_cic; | |
3261 | ||
3262 | /* If there are other queues in the group, don't wait */ | |
3263 | if (cfqq->cfqg->nr_cfqq > 1) | |
3264 | return false; | |
3265 | ||
3266 | if (cfq_slice_used(cfqq)) | |
3267 | return true; | |
3268 | ||
3269 | /* if slice left is less than think time, wait busy */ | |
3270 | if (cic && sample_valid(cic->ttime_samples) | |
3271 | && (cfqq->slice_end - jiffies < cic->ttime_mean)) | |
3272 | return true; | |
3273 | ||
3274 | /* | |
3275 | * If think times is less than a jiffy than ttime_mean=0 and above | |
3276 | * will not be true. It might happen that slice has not expired yet | |
3277 | * but will expire soon (4-5 ns) during select_queue(). To cover the | |
3278 | * case where think time is less than a jiffy, mark the queue wait | |
3279 | * busy if only 1 jiffy is left in the slice. | |
3280 | */ | |
3281 | if (cfqq->slice_end - jiffies == 1) | |
3282 | return true; | |
3283 | ||
3284 | return false; | |
3285 | } | |
3286 | ||
165125e1 | 3287 | static void cfq_completed_request(struct request_queue *q, struct request *rq) |
1da177e4 | 3288 | { |
5e705374 | 3289 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
b4878f24 | 3290 | struct cfq_data *cfqd = cfqq->cfqd; |
5380a101 | 3291 | const int sync = rq_is_sync(rq); |
b4878f24 | 3292 | unsigned long now; |
1da177e4 | 3293 | |
b4878f24 | 3294 | now = jiffies; |
2868ef7b | 3295 | cfq_log_cfqq(cfqd, cfqq, "complete rqnoidle %d", !!rq_noidle(rq)); |
1da177e4 | 3296 | |
45333d5a AC |
3297 | cfq_update_hw_tag(cfqd); |
3298 | ||
53c583d2 | 3299 | WARN_ON(!cfqd->rq_in_driver); |
6d048f53 | 3300 | WARN_ON(!cfqq->dispatched); |
53c583d2 | 3301 | cfqd->rq_in_driver--; |
6d048f53 | 3302 | cfqq->dispatched--; |
1da177e4 | 3303 | |
53c583d2 | 3304 | cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]--; |
3ed9a296 | 3305 | |
365722bb | 3306 | if (sync) { |
5e705374 | 3307 | RQ_CIC(rq)->last_end_request = now; |
573412b2 CZ |
3308 | if (!time_after(rq->start_time + cfqd->cfq_fifo_expire[1], now)) |
3309 | cfqd->last_delayed_sync = now; | |
365722bb | 3310 | } |
caaa5f9f JA |
3311 | |
3312 | /* | |
3313 | * If this is the active queue, check if it needs to be expired, | |
3314 | * or if we want to idle in case it has no pending requests. | |
3315 | */ | |
3316 | if (cfqd->active_queue == cfqq) { | |
a36e71f9 JA |
3317 | const bool cfqq_empty = RB_EMPTY_ROOT(&cfqq->sort_list); |
3318 | ||
44f7c160 JA |
3319 | if (cfq_cfqq_slice_new(cfqq)) { |
3320 | cfq_set_prio_slice(cfqd, cfqq); | |
3321 | cfq_clear_cfqq_slice_new(cfqq); | |
3322 | } | |
f75edf2d VG |
3323 | |
3324 | /* | |
7667aa06 VG |
3325 | * Should we wait for next request to come in before we expire |
3326 | * the queue. | |
f75edf2d | 3327 | */ |
7667aa06 | 3328 | if (cfq_should_wait_busy(cfqd, cfqq)) { |
f75edf2d VG |
3329 | cfqq->slice_end = jiffies + cfqd->cfq_slice_idle; |
3330 | cfq_mark_cfqq_wait_busy(cfqq); | |
b1ffe737 | 3331 | cfq_log_cfqq(cfqd, cfqq, "will busy wait"); |
f75edf2d VG |
3332 | } |
3333 | ||
a36e71f9 | 3334 | /* |
8e550632 CZ |
3335 | * Idling is not enabled on: |
3336 | * - expired queues | |
3337 | * - idle-priority queues | |
3338 | * - async queues | |
3339 | * - queues with still some requests queued | |
3340 | * - when there is a close cooperator | |
a36e71f9 | 3341 | */ |
0871714e | 3342 | if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq)) |
6084cdda | 3343 | cfq_slice_expired(cfqd, 1); |
8e550632 CZ |
3344 | else if (sync && cfqq_empty && |
3345 | !cfq_close_cooperator(cfqd, cfqq)) { | |
3346 | cfqd->noidle_tree_requires_idle |= !rq_noidle(rq); | |
3347 | /* | |
3348 | * Idling is enabled for SYNC_WORKLOAD. | |
3349 | * SYNC_NOIDLE_WORKLOAD idles at the end of the tree | |
3350 | * only if we processed at least one !rq_noidle request | |
3351 | */ | |
3352 | if (cfqd->serving_type == SYNC_WORKLOAD | |
c04645e5 VG |
3353 | || cfqd->noidle_tree_requires_idle |
3354 | || cfqq->cfqg->nr_cfqq == 1) | |
8e550632 CZ |
3355 | cfq_arm_slice_timer(cfqd); |
3356 | } | |
caaa5f9f | 3357 | } |
6d048f53 | 3358 | |
53c583d2 | 3359 | if (!cfqd->rq_in_driver) |
23e018a1 | 3360 | cfq_schedule_dispatch(cfqd); |
1da177e4 LT |
3361 | } |
3362 | ||
22e2c507 JA |
3363 | /* |
3364 | * we temporarily boost lower priority queues if they are holding fs exclusive | |
3365 | * resources. they are boosted to normal prio (CLASS_BE/4) | |
3366 | */ | |
3367 | static void cfq_prio_boost(struct cfq_queue *cfqq) | |
1da177e4 | 3368 | { |
22e2c507 JA |
3369 | if (has_fs_excl()) { |
3370 | /* | |
3371 | * boost idle prio on transactions that would lock out other | |
3372 | * users of the filesystem | |
3373 | */ | |
3374 | if (cfq_class_idle(cfqq)) | |
3375 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
3376 | if (cfqq->ioprio > IOPRIO_NORM) | |
3377 | cfqq->ioprio = IOPRIO_NORM; | |
3378 | } else { | |
3379 | /* | |
dddb7451 | 3380 | * unboost the queue (if needed) |
22e2c507 | 3381 | */ |
dddb7451 CZ |
3382 | cfqq->ioprio_class = cfqq->org_ioprio_class; |
3383 | cfqq->ioprio = cfqq->org_ioprio; | |
22e2c507 | 3384 | } |
22e2c507 | 3385 | } |
1da177e4 | 3386 | |
89850f7e | 3387 | static inline int __cfq_may_queue(struct cfq_queue *cfqq) |
22e2c507 | 3388 | { |
1b379d8d | 3389 | if (cfq_cfqq_wait_request(cfqq) && !cfq_cfqq_must_alloc_slice(cfqq)) { |
3b18152c | 3390 | cfq_mark_cfqq_must_alloc_slice(cfqq); |
22e2c507 | 3391 | return ELV_MQUEUE_MUST; |
3b18152c | 3392 | } |
1da177e4 | 3393 | |
22e2c507 | 3394 | return ELV_MQUEUE_MAY; |
22e2c507 JA |
3395 | } |
3396 | ||
165125e1 | 3397 | static int cfq_may_queue(struct request_queue *q, int rw) |
22e2c507 JA |
3398 | { |
3399 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
3400 | struct task_struct *tsk = current; | |
91fac317 | 3401 | struct cfq_io_context *cic; |
22e2c507 JA |
3402 | struct cfq_queue *cfqq; |
3403 | ||
3404 | /* | |
3405 | * don't force setup of a queue from here, as a call to may_queue | |
3406 | * does not necessarily imply that a request actually will be queued. | |
3407 | * so just lookup a possibly existing queue, or return 'may queue' | |
3408 | * if that fails | |
3409 | */ | |
4ac845a2 | 3410 | cic = cfq_cic_lookup(cfqd, tsk->io_context); |
91fac317 VT |
3411 | if (!cic) |
3412 | return ELV_MQUEUE_MAY; | |
3413 | ||
b0b78f81 | 3414 | cfqq = cic_to_cfqq(cic, rw_is_sync(rw)); |
22e2c507 | 3415 | if (cfqq) { |
fd0928df | 3416 | cfq_init_prio_data(cfqq, cic->ioc); |
22e2c507 JA |
3417 | cfq_prio_boost(cfqq); |
3418 | ||
89850f7e | 3419 | return __cfq_may_queue(cfqq); |
22e2c507 JA |
3420 | } |
3421 | ||
3422 | return ELV_MQUEUE_MAY; | |
1da177e4 LT |
3423 | } |
3424 | ||
1da177e4 LT |
3425 | /* |
3426 | * queue lock held here | |
3427 | */ | |
bb37b94c | 3428 | static void cfq_put_request(struct request *rq) |
1da177e4 | 3429 | { |
5e705374 | 3430 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
1da177e4 | 3431 | |
5e705374 | 3432 | if (cfqq) { |
22e2c507 | 3433 | const int rw = rq_data_dir(rq); |
1da177e4 | 3434 | |
22e2c507 JA |
3435 | BUG_ON(!cfqq->allocated[rw]); |
3436 | cfqq->allocated[rw]--; | |
1da177e4 | 3437 | |
5e705374 | 3438 | put_io_context(RQ_CIC(rq)->ioc); |
1da177e4 | 3439 | |
1da177e4 | 3440 | rq->elevator_private = NULL; |
5e705374 | 3441 | rq->elevator_private2 = NULL; |
1da177e4 | 3442 | |
1da177e4 LT |
3443 | cfq_put_queue(cfqq); |
3444 | } | |
3445 | } | |
3446 | ||
df5fe3e8 JM |
3447 | static struct cfq_queue * |
3448 | cfq_merge_cfqqs(struct cfq_data *cfqd, struct cfq_io_context *cic, | |
3449 | struct cfq_queue *cfqq) | |
3450 | { | |
3451 | cfq_log_cfqq(cfqd, cfqq, "merging with queue %p", cfqq->new_cfqq); | |
3452 | cic_set_cfqq(cic, cfqq->new_cfqq, 1); | |
b3b6d040 | 3453 | cfq_mark_cfqq_coop(cfqq->new_cfqq); |
df5fe3e8 JM |
3454 | cfq_put_queue(cfqq); |
3455 | return cic_to_cfqq(cic, 1); | |
3456 | } | |
3457 | ||
e6c5bc73 JM |
3458 | /* |
3459 | * Returns NULL if a new cfqq should be allocated, or the old cfqq if this | |
3460 | * was the last process referring to said cfqq. | |
3461 | */ | |
3462 | static struct cfq_queue * | |
3463 | split_cfqq(struct cfq_io_context *cic, struct cfq_queue *cfqq) | |
3464 | { | |
3465 | if (cfqq_process_refs(cfqq) == 1) { | |
e6c5bc73 JM |
3466 | cfqq->pid = current->pid; |
3467 | cfq_clear_cfqq_coop(cfqq); | |
ae54abed | 3468 | cfq_clear_cfqq_split_coop(cfqq); |
e6c5bc73 JM |
3469 | return cfqq; |
3470 | } | |
3471 | ||
3472 | cic_set_cfqq(cic, NULL, 1); | |
3473 | cfq_put_queue(cfqq); | |
3474 | return NULL; | |
3475 | } | |
1da177e4 | 3476 | /* |
22e2c507 | 3477 | * Allocate cfq data structures associated with this request. |
1da177e4 | 3478 | */ |
22e2c507 | 3479 | static int |
165125e1 | 3480 | cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask) |
1da177e4 LT |
3481 | { |
3482 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
3483 | struct cfq_io_context *cic; | |
3484 | const int rw = rq_data_dir(rq); | |
a6151c3a | 3485 | const bool is_sync = rq_is_sync(rq); |
22e2c507 | 3486 | struct cfq_queue *cfqq; |
1da177e4 LT |
3487 | unsigned long flags; |
3488 | ||
3489 | might_sleep_if(gfp_mask & __GFP_WAIT); | |
3490 | ||
e2d74ac0 | 3491 | cic = cfq_get_io_context(cfqd, gfp_mask); |
22e2c507 | 3492 | |
1da177e4 LT |
3493 | spin_lock_irqsave(q->queue_lock, flags); |
3494 | ||
22e2c507 JA |
3495 | if (!cic) |
3496 | goto queue_fail; | |
3497 | ||
e6c5bc73 | 3498 | new_queue: |
91fac317 | 3499 | cfqq = cic_to_cfqq(cic, is_sync); |
32f2e807 | 3500 | if (!cfqq || cfqq == &cfqd->oom_cfqq) { |
fd0928df | 3501 | cfqq = cfq_get_queue(cfqd, is_sync, cic->ioc, gfp_mask); |
91fac317 | 3502 | cic_set_cfqq(cic, cfqq, is_sync); |
df5fe3e8 | 3503 | } else { |
e6c5bc73 JM |
3504 | /* |
3505 | * If the queue was seeky for too long, break it apart. | |
3506 | */ | |
ae54abed | 3507 | if (cfq_cfqq_coop(cfqq) && cfq_cfqq_split_coop(cfqq)) { |
e6c5bc73 JM |
3508 | cfq_log_cfqq(cfqd, cfqq, "breaking apart cfqq"); |
3509 | cfqq = split_cfqq(cic, cfqq); | |
3510 | if (!cfqq) | |
3511 | goto new_queue; | |
3512 | } | |
3513 | ||
df5fe3e8 JM |
3514 | /* |
3515 | * Check to see if this queue is scheduled to merge with | |
3516 | * another, closely cooperating queue. The merging of | |
3517 | * queues happens here as it must be done in process context. | |
3518 | * The reference on new_cfqq was taken in merge_cfqqs. | |
3519 | */ | |
3520 | if (cfqq->new_cfqq) | |
3521 | cfqq = cfq_merge_cfqqs(cfqd, cic, cfqq); | |
91fac317 | 3522 | } |
1da177e4 LT |
3523 | |
3524 | cfqq->allocated[rw]++; | |
22e2c507 | 3525 | atomic_inc(&cfqq->ref); |
1da177e4 | 3526 | |
5e705374 | 3527 | spin_unlock_irqrestore(q->queue_lock, flags); |
3b18152c | 3528 | |
5e705374 JA |
3529 | rq->elevator_private = cic; |
3530 | rq->elevator_private2 = cfqq; | |
3531 | return 0; | |
1da177e4 | 3532 | |
22e2c507 JA |
3533 | queue_fail: |
3534 | if (cic) | |
3535 | put_io_context(cic->ioc); | |
89850f7e | 3536 | |
23e018a1 | 3537 | cfq_schedule_dispatch(cfqd); |
1da177e4 | 3538 | spin_unlock_irqrestore(q->queue_lock, flags); |
7b679138 | 3539 | cfq_log(cfqd, "set_request fail"); |
1da177e4 LT |
3540 | return 1; |
3541 | } | |
3542 | ||
65f27f38 | 3543 | static void cfq_kick_queue(struct work_struct *work) |
22e2c507 | 3544 | { |
65f27f38 | 3545 | struct cfq_data *cfqd = |
23e018a1 | 3546 | container_of(work, struct cfq_data, unplug_work); |
165125e1 | 3547 | struct request_queue *q = cfqd->queue; |
22e2c507 | 3548 | |
40bb54d1 | 3549 | spin_lock_irq(q->queue_lock); |
a7f55792 | 3550 | __blk_run_queue(cfqd->queue); |
40bb54d1 | 3551 | spin_unlock_irq(q->queue_lock); |
22e2c507 JA |
3552 | } |
3553 | ||
3554 | /* | |
3555 | * Timer running if the active_queue is currently idling inside its time slice | |
3556 | */ | |
3557 | static void cfq_idle_slice_timer(unsigned long data) | |
3558 | { | |
3559 | struct cfq_data *cfqd = (struct cfq_data *) data; | |
3560 | struct cfq_queue *cfqq; | |
3561 | unsigned long flags; | |
3c6bd2f8 | 3562 | int timed_out = 1; |
22e2c507 | 3563 | |
7b679138 JA |
3564 | cfq_log(cfqd, "idle timer fired"); |
3565 | ||
22e2c507 JA |
3566 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); |
3567 | ||
fe094d98 JA |
3568 | cfqq = cfqd->active_queue; |
3569 | if (cfqq) { | |
3c6bd2f8 JA |
3570 | timed_out = 0; |
3571 | ||
b029195d JA |
3572 | /* |
3573 | * We saw a request before the queue expired, let it through | |
3574 | */ | |
3575 | if (cfq_cfqq_must_dispatch(cfqq)) | |
3576 | goto out_kick; | |
3577 | ||
22e2c507 JA |
3578 | /* |
3579 | * expired | |
3580 | */ | |
44f7c160 | 3581 | if (cfq_slice_used(cfqq)) |
22e2c507 JA |
3582 | goto expire; |
3583 | ||
3584 | /* | |
3585 | * only expire and reinvoke request handler, if there are | |
3586 | * other queues with pending requests | |
3587 | */ | |
caaa5f9f | 3588 | if (!cfqd->busy_queues) |
22e2c507 | 3589 | goto out_cont; |
22e2c507 JA |
3590 | |
3591 | /* | |
3592 | * not expired and it has a request pending, let it dispatch | |
3593 | */ | |
75e50984 | 3594 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
22e2c507 | 3595 | goto out_kick; |
76280aff CZ |
3596 | |
3597 | /* | |
3598 | * Queue depth flag is reset only when the idle didn't succeed | |
3599 | */ | |
3600 | cfq_clear_cfqq_deep(cfqq); | |
22e2c507 JA |
3601 | } |
3602 | expire: | |
6084cdda | 3603 | cfq_slice_expired(cfqd, timed_out); |
22e2c507 | 3604 | out_kick: |
23e018a1 | 3605 | cfq_schedule_dispatch(cfqd); |
22e2c507 JA |
3606 | out_cont: |
3607 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
3608 | } | |
3609 | ||
3b18152c JA |
3610 | static void cfq_shutdown_timer_wq(struct cfq_data *cfqd) |
3611 | { | |
3612 | del_timer_sync(&cfqd->idle_slice_timer); | |
23e018a1 | 3613 | cancel_work_sync(&cfqd->unplug_work); |
3b18152c | 3614 | } |
22e2c507 | 3615 | |
c2dea2d1 VT |
3616 | static void cfq_put_async_queues(struct cfq_data *cfqd) |
3617 | { | |
3618 | int i; | |
3619 | ||
3620 | for (i = 0; i < IOPRIO_BE_NR; i++) { | |
3621 | if (cfqd->async_cfqq[0][i]) | |
3622 | cfq_put_queue(cfqd->async_cfqq[0][i]); | |
3623 | if (cfqd->async_cfqq[1][i]) | |
3624 | cfq_put_queue(cfqd->async_cfqq[1][i]); | |
c2dea2d1 | 3625 | } |
2389d1ef ON |
3626 | |
3627 | if (cfqd->async_idle_cfqq) | |
3628 | cfq_put_queue(cfqd->async_idle_cfqq); | |
c2dea2d1 VT |
3629 | } |
3630 | ||
bb729bc9 JA |
3631 | static void cfq_cfqd_free(struct rcu_head *head) |
3632 | { | |
3633 | kfree(container_of(head, struct cfq_data, rcu)); | |
3634 | } | |
3635 | ||
b374d18a | 3636 | static void cfq_exit_queue(struct elevator_queue *e) |
1da177e4 | 3637 | { |
22e2c507 | 3638 | struct cfq_data *cfqd = e->elevator_data; |
165125e1 | 3639 | struct request_queue *q = cfqd->queue; |
22e2c507 | 3640 | |
3b18152c | 3641 | cfq_shutdown_timer_wq(cfqd); |
e2d74ac0 | 3642 | |
d9ff4187 | 3643 | spin_lock_irq(q->queue_lock); |
e2d74ac0 | 3644 | |
d9ff4187 | 3645 | if (cfqd->active_queue) |
6084cdda | 3646 | __cfq_slice_expired(cfqd, cfqd->active_queue, 0); |
e2d74ac0 JA |
3647 | |
3648 | while (!list_empty(&cfqd->cic_list)) { | |
d9ff4187 AV |
3649 | struct cfq_io_context *cic = list_entry(cfqd->cic_list.next, |
3650 | struct cfq_io_context, | |
3651 | queue_list); | |
89850f7e JA |
3652 | |
3653 | __cfq_exit_single_io_context(cfqd, cic); | |
d9ff4187 | 3654 | } |
e2d74ac0 | 3655 | |
c2dea2d1 | 3656 | cfq_put_async_queues(cfqd); |
b1c35769 VG |
3657 | cfq_release_cfq_groups(cfqd); |
3658 | blkiocg_del_blkio_group(&cfqd->root_group.blkg); | |
15c31be4 | 3659 | |
d9ff4187 | 3660 | spin_unlock_irq(q->queue_lock); |
a90d742e AV |
3661 | |
3662 | cfq_shutdown_timer_wq(cfqd); | |
3663 | ||
b1c35769 | 3664 | /* Wait for cfqg->blkg->key accessors to exit their grace periods. */ |
bb729bc9 | 3665 | call_rcu(&cfqd->rcu, cfq_cfqd_free); |
1da177e4 LT |
3666 | } |
3667 | ||
165125e1 | 3668 | static void *cfq_init_queue(struct request_queue *q) |
1da177e4 LT |
3669 | { |
3670 | struct cfq_data *cfqd; | |
718eee05 | 3671 | int i, j; |
cdb16e8f | 3672 | struct cfq_group *cfqg; |
615f0259 | 3673 | struct cfq_rb_root *st; |
1da177e4 | 3674 | |
94f6030c | 3675 | cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL | __GFP_ZERO, q->node); |
1da177e4 | 3676 | if (!cfqd) |
bc1c1169 | 3677 | return NULL; |
1da177e4 | 3678 | |
1fa8f6d6 VG |
3679 | /* Init root service tree */ |
3680 | cfqd->grp_service_tree = CFQ_RB_ROOT; | |
3681 | ||
cdb16e8f VG |
3682 | /* Init root group */ |
3683 | cfqg = &cfqd->root_group; | |
615f0259 VG |
3684 | for_each_cfqg_st(cfqg, i, j, st) |
3685 | *st = CFQ_RB_ROOT; | |
1fa8f6d6 | 3686 | RB_CLEAR_NODE(&cfqg->rb_node); |
26a2ac00 | 3687 | |
25bc6b07 VG |
3688 | /* Give preference to root group over other groups */ |
3689 | cfqg->weight = 2*BLKIO_WEIGHT_DEFAULT; | |
3690 | ||
25fb5169 | 3691 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
b1c35769 VG |
3692 | /* |
3693 | * Take a reference to root group which we never drop. This is just | |
3694 | * to make sure that cfq_put_cfqg() does not try to kfree root group | |
3695 | */ | |
3696 | atomic_set(&cfqg->ref, 1); | |
22084190 VG |
3697 | blkiocg_add_blkio_group(&blkio_root_cgroup, &cfqg->blkg, (void *)cfqd, |
3698 | 0); | |
25fb5169 | 3699 | #endif |
26a2ac00 JA |
3700 | /* |
3701 | * Not strictly needed (since RB_ROOT just clears the node and we | |
3702 | * zeroed cfqd on alloc), but better be safe in case someone decides | |
3703 | * to add magic to the rb code | |
3704 | */ | |
3705 | for (i = 0; i < CFQ_PRIO_LISTS; i++) | |
3706 | cfqd->prio_trees[i] = RB_ROOT; | |
3707 | ||
6118b70b JA |
3708 | /* |
3709 | * Our fallback cfqq if cfq_find_alloc_queue() runs into OOM issues. | |
3710 | * Grab a permanent reference to it, so that the normal code flow | |
3711 | * will not attempt to free it. | |
3712 | */ | |
3713 | cfq_init_cfqq(cfqd, &cfqd->oom_cfqq, 1, 0); | |
3714 | atomic_inc(&cfqd->oom_cfqq.ref); | |
cdb16e8f | 3715 | cfq_link_cfqq_cfqg(&cfqd->oom_cfqq, &cfqd->root_group); |
6118b70b | 3716 | |
d9ff4187 | 3717 | INIT_LIST_HEAD(&cfqd->cic_list); |
1da177e4 | 3718 | |
1da177e4 | 3719 | cfqd->queue = q; |
1da177e4 | 3720 | |
22e2c507 JA |
3721 | init_timer(&cfqd->idle_slice_timer); |
3722 | cfqd->idle_slice_timer.function = cfq_idle_slice_timer; | |
3723 | cfqd->idle_slice_timer.data = (unsigned long) cfqd; | |
3724 | ||
23e018a1 | 3725 | INIT_WORK(&cfqd->unplug_work, cfq_kick_queue); |
22e2c507 | 3726 | |
1da177e4 | 3727 | cfqd->cfq_quantum = cfq_quantum; |
22e2c507 JA |
3728 | cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; |
3729 | cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; | |
1da177e4 LT |
3730 | cfqd->cfq_back_max = cfq_back_max; |
3731 | cfqd->cfq_back_penalty = cfq_back_penalty; | |
22e2c507 JA |
3732 | cfqd->cfq_slice[0] = cfq_slice_async; |
3733 | cfqd->cfq_slice[1] = cfq_slice_sync; | |
3734 | cfqd->cfq_slice_async_rq = cfq_slice_async_rq; | |
3735 | cfqd->cfq_slice_idle = cfq_slice_idle; | |
963b72fc | 3736 | cfqd->cfq_latency = 1; |
ae30c286 | 3737 | cfqd->cfq_group_isolation = 0; |
e459dd08 | 3738 | cfqd->hw_tag = -1; |
edc71131 CZ |
3739 | /* |
3740 | * we optimistically start assuming sync ops weren't delayed in last | |
3741 | * second, in order to have larger depth for async operations. | |
3742 | */ | |
573412b2 | 3743 | cfqd->last_delayed_sync = jiffies - HZ; |
bb729bc9 | 3744 | INIT_RCU_HEAD(&cfqd->rcu); |
bc1c1169 | 3745 | return cfqd; |
1da177e4 LT |
3746 | } |
3747 | ||
3748 | static void cfq_slab_kill(void) | |
3749 | { | |
d6de8be7 JA |
3750 | /* |
3751 | * Caller already ensured that pending RCU callbacks are completed, | |
3752 | * so we should have no busy allocations at this point. | |
3753 | */ | |
1da177e4 LT |
3754 | if (cfq_pool) |
3755 | kmem_cache_destroy(cfq_pool); | |
3756 | if (cfq_ioc_pool) | |
3757 | kmem_cache_destroy(cfq_ioc_pool); | |
3758 | } | |
3759 | ||
3760 | static int __init cfq_slab_setup(void) | |
3761 | { | |
0a31bd5f | 3762 | cfq_pool = KMEM_CACHE(cfq_queue, 0); |
1da177e4 LT |
3763 | if (!cfq_pool) |
3764 | goto fail; | |
3765 | ||
34e6bbf2 | 3766 | cfq_ioc_pool = KMEM_CACHE(cfq_io_context, 0); |
1da177e4 LT |
3767 | if (!cfq_ioc_pool) |
3768 | goto fail; | |
3769 | ||
3770 | return 0; | |
3771 | fail: | |
3772 | cfq_slab_kill(); | |
3773 | return -ENOMEM; | |
3774 | } | |
3775 | ||
1da177e4 LT |
3776 | /* |
3777 | * sysfs parts below --> | |
3778 | */ | |
1da177e4 LT |
3779 | static ssize_t |
3780 | cfq_var_show(unsigned int var, char *page) | |
3781 | { | |
3782 | return sprintf(page, "%d\n", var); | |
3783 | } | |
3784 | ||
3785 | static ssize_t | |
3786 | cfq_var_store(unsigned int *var, const char *page, size_t count) | |
3787 | { | |
3788 | char *p = (char *) page; | |
3789 | ||
3790 | *var = simple_strtoul(p, &p, 10); | |
3791 | return count; | |
3792 | } | |
3793 | ||
1da177e4 | 3794 | #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ |
b374d18a | 3795 | static ssize_t __FUNC(struct elevator_queue *e, char *page) \ |
1da177e4 | 3796 | { \ |
3d1ab40f | 3797 | struct cfq_data *cfqd = e->elevator_data; \ |
1da177e4 LT |
3798 | unsigned int __data = __VAR; \ |
3799 | if (__CONV) \ | |
3800 | __data = jiffies_to_msecs(__data); \ | |
3801 | return cfq_var_show(__data, (page)); \ | |
3802 | } | |
3803 | SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); | |
22e2c507 JA |
3804 | SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1); |
3805 | SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1); | |
e572ec7e AV |
3806 | SHOW_FUNCTION(cfq_back_seek_max_show, cfqd->cfq_back_max, 0); |
3807 | SHOW_FUNCTION(cfq_back_seek_penalty_show, cfqd->cfq_back_penalty, 0); | |
22e2c507 JA |
3808 | SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1); |
3809 | SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1); | |
3810 | SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1); | |
3811 | SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0); | |
963b72fc | 3812 | SHOW_FUNCTION(cfq_low_latency_show, cfqd->cfq_latency, 0); |
ae30c286 | 3813 | SHOW_FUNCTION(cfq_group_isolation_show, cfqd->cfq_group_isolation, 0); |
1da177e4 LT |
3814 | #undef SHOW_FUNCTION |
3815 | ||
3816 | #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ | |
b374d18a | 3817 | static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \ |
1da177e4 | 3818 | { \ |
3d1ab40f | 3819 | struct cfq_data *cfqd = e->elevator_data; \ |
1da177e4 LT |
3820 | unsigned int __data; \ |
3821 | int ret = cfq_var_store(&__data, (page), count); \ | |
3822 | if (__data < (MIN)) \ | |
3823 | __data = (MIN); \ | |
3824 | else if (__data > (MAX)) \ | |
3825 | __data = (MAX); \ | |
3826 | if (__CONV) \ | |
3827 | *(__PTR) = msecs_to_jiffies(__data); \ | |
3828 | else \ | |
3829 | *(__PTR) = __data; \ | |
3830 | return ret; \ | |
3831 | } | |
3832 | STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); | |
fe094d98 JA |
3833 | STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, |
3834 | UINT_MAX, 1); | |
3835 | STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, | |
3836 | UINT_MAX, 1); | |
e572ec7e | 3837 | STORE_FUNCTION(cfq_back_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); |
fe094d98 JA |
3838 | STORE_FUNCTION(cfq_back_seek_penalty_store, &cfqd->cfq_back_penalty, 1, |
3839 | UINT_MAX, 0); | |
22e2c507 JA |
3840 | STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1); |
3841 | STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1); | |
3842 | STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1); | |
fe094d98 JA |
3843 | STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, |
3844 | UINT_MAX, 0); | |
963b72fc | 3845 | STORE_FUNCTION(cfq_low_latency_store, &cfqd->cfq_latency, 0, 1, 0); |
ae30c286 | 3846 | STORE_FUNCTION(cfq_group_isolation_store, &cfqd->cfq_group_isolation, 0, 1, 0); |
1da177e4 LT |
3847 | #undef STORE_FUNCTION |
3848 | ||
e572ec7e AV |
3849 | #define CFQ_ATTR(name) \ |
3850 | __ATTR(name, S_IRUGO|S_IWUSR, cfq_##name##_show, cfq_##name##_store) | |
3851 | ||
3852 | static struct elv_fs_entry cfq_attrs[] = { | |
3853 | CFQ_ATTR(quantum), | |
e572ec7e AV |
3854 | CFQ_ATTR(fifo_expire_sync), |
3855 | CFQ_ATTR(fifo_expire_async), | |
3856 | CFQ_ATTR(back_seek_max), | |
3857 | CFQ_ATTR(back_seek_penalty), | |
3858 | CFQ_ATTR(slice_sync), | |
3859 | CFQ_ATTR(slice_async), | |
3860 | CFQ_ATTR(slice_async_rq), | |
3861 | CFQ_ATTR(slice_idle), | |
963b72fc | 3862 | CFQ_ATTR(low_latency), |
ae30c286 | 3863 | CFQ_ATTR(group_isolation), |
e572ec7e | 3864 | __ATTR_NULL |
1da177e4 LT |
3865 | }; |
3866 | ||
1da177e4 LT |
3867 | static struct elevator_type iosched_cfq = { |
3868 | .ops = { | |
3869 | .elevator_merge_fn = cfq_merge, | |
3870 | .elevator_merged_fn = cfq_merged_request, | |
3871 | .elevator_merge_req_fn = cfq_merged_requests, | |
da775265 | 3872 | .elevator_allow_merge_fn = cfq_allow_merge, |
b4878f24 | 3873 | .elevator_dispatch_fn = cfq_dispatch_requests, |
1da177e4 | 3874 | .elevator_add_req_fn = cfq_insert_request, |
b4878f24 | 3875 | .elevator_activate_req_fn = cfq_activate_request, |
1da177e4 LT |
3876 | .elevator_deactivate_req_fn = cfq_deactivate_request, |
3877 | .elevator_queue_empty_fn = cfq_queue_empty, | |
3878 | .elevator_completed_req_fn = cfq_completed_request, | |
21183b07 JA |
3879 | .elevator_former_req_fn = elv_rb_former_request, |
3880 | .elevator_latter_req_fn = elv_rb_latter_request, | |
1da177e4 LT |
3881 | .elevator_set_req_fn = cfq_set_request, |
3882 | .elevator_put_req_fn = cfq_put_request, | |
3883 | .elevator_may_queue_fn = cfq_may_queue, | |
3884 | .elevator_init_fn = cfq_init_queue, | |
3885 | .elevator_exit_fn = cfq_exit_queue, | |
fc46379d | 3886 | .trim = cfq_free_io_context, |
1da177e4 | 3887 | }, |
3d1ab40f | 3888 | .elevator_attrs = cfq_attrs, |
1da177e4 LT |
3889 | .elevator_name = "cfq", |
3890 | .elevator_owner = THIS_MODULE, | |
3891 | }; | |
3892 | ||
3e252066 VG |
3893 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
3894 | static struct blkio_policy_type blkio_policy_cfq = { | |
3895 | .ops = { | |
3896 | .blkio_unlink_group_fn = cfq_unlink_blkio_group, | |
3897 | .blkio_update_group_weight_fn = cfq_update_blkio_group_weight, | |
3898 | }, | |
3899 | }; | |
3900 | #else | |
3901 | static struct blkio_policy_type blkio_policy_cfq; | |
3902 | #endif | |
3903 | ||
1da177e4 LT |
3904 | static int __init cfq_init(void) |
3905 | { | |
22e2c507 JA |
3906 | /* |
3907 | * could be 0 on HZ < 1000 setups | |
3908 | */ | |
3909 | if (!cfq_slice_async) | |
3910 | cfq_slice_async = 1; | |
3911 | if (!cfq_slice_idle) | |
3912 | cfq_slice_idle = 1; | |
3913 | ||
1da177e4 LT |
3914 | if (cfq_slab_setup()) |
3915 | return -ENOMEM; | |
3916 | ||
2fdd82bd | 3917 | elv_register(&iosched_cfq); |
3e252066 | 3918 | blkio_policy_register(&blkio_policy_cfq); |
1da177e4 | 3919 | |
2fdd82bd | 3920 | return 0; |
1da177e4 LT |
3921 | } |
3922 | ||
3923 | static void __exit cfq_exit(void) | |
3924 | { | |
6e9a4738 | 3925 | DECLARE_COMPLETION_ONSTACK(all_gone); |
3e252066 | 3926 | blkio_policy_unregister(&blkio_policy_cfq); |
1da177e4 | 3927 | elv_unregister(&iosched_cfq); |
334e94de | 3928 | ioc_gone = &all_gone; |
fba82272 OH |
3929 | /* ioc_gone's update must be visible before reading ioc_count */ |
3930 | smp_wmb(); | |
d6de8be7 JA |
3931 | |
3932 | /* | |
3933 | * this also protects us from entering cfq_slab_kill() with | |
3934 | * pending RCU callbacks | |
3935 | */ | |
245b2e70 | 3936 | if (elv_ioc_count_read(cfq_ioc_count)) |
9a11b4ed | 3937 | wait_for_completion(&all_gone); |
83521d3e | 3938 | cfq_slab_kill(); |
1da177e4 LT |
3939 | } |
3940 | ||
3941 | module_init(cfq_init); | |
3942 | module_exit(cfq_exit); | |
3943 | ||
3944 | MODULE_AUTHOR("Jens Axboe"); | |
3945 | MODULE_LICENSE("GPL"); | |
3946 | MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler"); |