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Commit | Line | Data |
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1da177e4 | 1 | /* |
1da177e4 LT |
2 | * CFQ, or complete fairness queueing, disk scheduler. |
3 | * | |
4 | * Based on ideas from a previously unfinished io | |
5 | * scheduler (round robin per-process disk scheduling) and Andrea Arcangeli. | |
6 | * | |
0fe23479 | 7 | * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk> |
1da177e4 | 8 | */ |
1da177e4 | 9 | #include <linux/module.h> |
1cc9be68 AV |
10 | #include <linux/blkdev.h> |
11 | #include <linux/elevator.h> | |
ad5ebd2f | 12 | #include <linux/jiffies.h> |
1da177e4 | 13 | #include <linux/rbtree.h> |
22e2c507 | 14 | #include <linux/ioprio.h> |
7b679138 | 15 | #include <linux/blktrace_api.h> |
25bc6b07 | 16 | #include "blk-cgroup.h" |
1da177e4 LT |
17 | |
18 | /* | |
19 | * tunables | |
20 | */ | |
fe094d98 | 21 | /* max queue in one round of service */ |
abc3c744 | 22 | static const int cfq_quantum = 8; |
64100099 | 23 | static const int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 }; |
fe094d98 JA |
24 | /* maximum backwards seek, in KiB */ |
25 | static const int cfq_back_max = 16 * 1024; | |
26 | /* penalty of a backwards seek */ | |
27 | static const int cfq_back_penalty = 2; | |
64100099 | 28 | static const int cfq_slice_sync = HZ / 10; |
3b18152c | 29 | static int cfq_slice_async = HZ / 25; |
64100099 | 30 | static const int cfq_slice_async_rq = 2; |
caaa5f9f | 31 | static int cfq_slice_idle = HZ / 125; |
5db5d642 CZ |
32 | static const int cfq_target_latency = HZ * 3/10; /* 300 ms */ |
33 | static const int cfq_hist_divisor = 4; | |
22e2c507 | 34 | |
d9e7620e | 35 | /* |
0871714e | 36 | * offset from end of service tree |
d9e7620e | 37 | */ |
0871714e | 38 | #define CFQ_IDLE_DELAY (HZ / 5) |
d9e7620e JA |
39 | |
40 | /* | |
41 | * below this threshold, we consider thinktime immediate | |
42 | */ | |
43 | #define CFQ_MIN_TT (2) | |
44 | ||
22e2c507 | 45 | #define CFQ_SLICE_SCALE (5) |
45333d5a | 46 | #define CFQ_HW_QUEUE_MIN (5) |
25bc6b07 | 47 | #define CFQ_SERVICE_SHIFT 12 |
22e2c507 | 48 | |
3dde36dd | 49 | #define CFQQ_SEEK_THR (sector_t)(8 * 100) |
e9ce335d | 50 | #define CFQQ_CLOSE_THR (sector_t)(8 * 1024) |
41647e7a | 51 | #define CFQQ_SECT_THR_NONROT (sector_t)(2 * 32) |
3dde36dd | 52 | #define CFQQ_SEEKY(cfqq) (hweight32(cfqq->seek_history) > 32/8) |
ae54abed | 53 | |
fe094d98 JA |
54 | #define RQ_CIC(rq) \ |
55 | ((struct cfq_io_context *) (rq)->elevator_private) | |
7b679138 | 56 | #define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elevator_private2) |
1da177e4 | 57 | |
e18b890b CL |
58 | static struct kmem_cache *cfq_pool; |
59 | static struct kmem_cache *cfq_ioc_pool; | |
1da177e4 | 60 | |
245b2e70 | 61 | static DEFINE_PER_CPU(unsigned long, cfq_ioc_count); |
334e94de | 62 | static struct completion *ioc_gone; |
9a11b4ed | 63 | static DEFINE_SPINLOCK(ioc_gone_lock); |
334e94de | 64 | |
22e2c507 JA |
65 | #define CFQ_PRIO_LISTS IOPRIO_BE_NR |
66 | #define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE) | |
22e2c507 JA |
67 | #define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT) |
68 | ||
206dc69b | 69 | #define sample_valid(samples) ((samples) > 80) |
1fa8f6d6 | 70 | #define rb_entry_cfqg(node) rb_entry((node), struct cfq_group, rb_node) |
206dc69b | 71 | |
cc09e299 JA |
72 | /* |
73 | * Most of our rbtree usage is for sorting with min extraction, so | |
74 | * if we cache the leftmost node we don't have to walk down the tree | |
75 | * to find it. Idea borrowed from Ingo Molnars CFS scheduler. We should | |
76 | * move this into the elevator for the rq sorting as well. | |
77 | */ | |
78 | struct cfq_rb_root { | |
79 | struct rb_root rb; | |
80 | struct rb_node *left; | |
aa6f6a3d | 81 | unsigned count; |
73e9ffdd | 82 | unsigned total_weight; |
1fa8f6d6 | 83 | u64 min_vdisktime; |
25bc6b07 | 84 | struct rb_node *active; |
cc09e299 | 85 | }; |
73e9ffdd RK |
86 | #define CFQ_RB_ROOT (struct cfq_rb_root) { .rb = RB_ROOT, .left = NULL, \ |
87 | .count = 0, .min_vdisktime = 0, } | |
cc09e299 | 88 | |
6118b70b JA |
89 | /* |
90 | * Per process-grouping structure | |
91 | */ | |
92 | struct cfq_queue { | |
93 | /* reference count */ | |
94 | atomic_t ref; | |
95 | /* various state flags, see below */ | |
96 | unsigned int flags; | |
97 | /* parent cfq_data */ | |
98 | struct cfq_data *cfqd; | |
99 | /* service_tree member */ | |
100 | struct rb_node rb_node; | |
101 | /* service_tree key */ | |
102 | unsigned long rb_key; | |
103 | /* prio tree member */ | |
104 | struct rb_node p_node; | |
105 | /* prio tree root we belong to, if any */ | |
106 | struct rb_root *p_root; | |
107 | /* sorted list of pending requests */ | |
108 | struct rb_root sort_list; | |
109 | /* if fifo isn't expired, next request to serve */ | |
110 | struct request *next_rq; | |
111 | /* requests queued in sort_list */ | |
112 | int queued[2]; | |
113 | /* currently allocated requests */ | |
114 | int allocated[2]; | |
115 | /* fifo list of requests in sort_list */ | |
116 | struct list_head fifo; | |
117 | ||
dae739eb VG |
118 | /* time when queue got scheduled in to dispatch first request. */ |
119 | unsigned long dispatch_start; | |
f75edf2d | 120 | unsigned int allocated_slice; |
c4081ba5 | 121 | unsigned int slice_dispatch; |
dae739eb VG |
122 | /* time when first request from queue completed and slice started. */ |
123 | unsigned long slice_start; | |
6118b70b JA |
124 | unsigned long slice_end; |
125 | long slice_resid; | |
6118b70b JA |
126 | |
127 | /* pending metadata requests */ | |
128 | int meta_pending; | |
129 | /* number of requests that are on the dispatch list or inside driver */ | |
130 | int dispatched; | |
131 | ||
132 | /* io prio of this group */ | |
133 | unsigned short ioprio, org_ioprio; | |
134 | unsigned short ioprio_class, org_ioprio_class; | |
135 | ||
c4081ba5 RK |
136 | pid_t pid; |
137 | ||
3dde36dd | 138 | u32 seek_history; |
b2c18e1e JM |
139 | sector_t last_request_pos; |
140 | ||
aa6f6a3d | 141 | struct cfq_rb_root *service_tree; |
df5fe3e8 | 142 | struct cfq_queue *new_cfqq; |
cdb16e8f | 143 | struct cfq_group *cfqg; |
ae30c286 | 144 | struct cfq_group *orig_cfqg; |
6118b70b JA |
145 | }; |
146 | ||
c0324a02 | 147 | /* |
718eee05 | 148 | * First index in the service_trees. |
c0324a02 CZ |
149 | * IDLE is handled separately, so it has negative index |
150 | */ | |
151 | enum wl_prio_t { | |
c0324a02 | 152 | BE_WORKLOAD = 0, |
615f0259 VG |
153 | RT_WORKLOAD = 1, |
154 | IDLE_WORKLOAD = 2, | |
c0324a02 CZ |
155 | }; |
156 | ||
718eee05 CZ |
157 | /* |
158 | * Second index in the service_trees. | |
159 | */ | |
160 | enum wl_type_t { | |
161 | ASYNC_WORKLOAD = 0, | |
162 | SYNC_NOIDLE_WORKLOAD = 1, | |
163 | SYNC_WORKLOAD = 2 | |
164 | }; | |
165 | ||
cdb16e8f VG |
166 | /* This is per cgroup per device grouping structure */ |
167 | struct cfq_group { | |
1fa8f6d6 VG |
168 | /* group service_tree member */ |
169 | struct rb_node rb_node; | |
170 | ||
171 | /* group service_tree key */ | |
172 | u64 vdisktime; | |
25bc6b07 | 173 | unsigned int weight; |
1fa8f6d6 VG |
174 | bool on_st; |
175 | ||
176 | /* number of cfqq currently on this group */ | |
177 | int nr_cfqq; | |
178 | ||
58ff82f3 VG |
179 | /* Per group busy queus average. Useful for workload slice calc. */ |
180 | unsigned int busy_queues_avg[2]; | |
cdb16e8f VG |
181 | /* |
182 | * rr lists of queues with requests, onle rr for each priority class. | |
183 | * Counts are embedded in the cfq_rb_root | |
184 | */ | |
185 | struct cfq_rb_root service_trees[2][3]; | |
186 | struct cfq_rb_root service_tree_idle; | |
dae739eb VG |
187 | |
188 | unsigned long saved_workload_slice; | |
189 | enum wl_type_t saved_workload; | |
190 | enum wl_prio_t saved_serving_prio; | |
25fb5169 VG |
191 | struct blkio_group blkg; |
192 | #ifdef CONFIG_CFQ_GROUP_IOSCHED | |
193 | struct hlist_node cfqd_node; | |
b1c35769 | 194 | atomic_t ref; |
25fb5169 | 195 | #endif |
cdb16e8f | 196 | }; |
718eee05 | 197 | |
22e2c507 JA |
198 | /* |
199 | * Per block device queue structure | |
200 | */ | |
1da177e4 | 201 | struct cfq_data { |
165125e1 | 202 | struct request_queue *queue; |
1fa8f6d6 VG |
203 | /* Root service tree for cfq_groups */ |
204 | struct cfq_rb_root grp_service_tree; | |
cdb16e8f | 205 | struct cfq_group root_group; |
22e2c507 | 206 | |
c0324a02 CZ |
207 | /* |
208 | * The priority currently being served | |
22e2c507 | 209 | */ |
c0324a02 | 210 | enum wl_prio_t serving_prio; |
718eee05 CZ |
211 | enum wl_type_t serving_type; |
212 | unsigned long workload_expires; | |
cdb16e8f | 213 | struct cfq_group *serving_group; |
8e550632 | 214 | bool noidle_tree_requires_idle; |
a36e71f9 JA |
215 | |
216 | /* | |
217 | * Each priority tree is sorted by next_request position. These | |
218 | * trees are used when determining if two or more queues are | |
219 | * interleaving requests (see cfq_close_cooperator). | |
220 | */ | |
221 | struct rb_root prio_trees[CFQ_PRIO_LISTS]; | |
222 | ||
22e2c507 JA |
223 | unsigned int busy_queues; |
224 | ||
53c583d2 CZ |
225 | int rq_in_driver; |
226 | int rq_in_flight[2]; | |
45333d5a AC |
227 | |
228 | /* | |
229 | * queue-depth detection | |
230 | */ | |
231 | int rq_queued; | |
25776e35 | 232 | int hw_tag; |
e459dd08 CZ |
233 | /* |
234 | * hw_tag can be | |
235 | * -1 => indeterminate, (cfq will behave as if NCQ is present, to allow better detection) | |
236 | * 1 => NCQ is present (hw_tag_est_depth is the estimated max depth) | |
237 | * 0 => no NCQ | |
238 | */ | |
239 | int hw_tag_est_depth; | |
240 | unsigned int hw_tag_samples; | |
1da177e4 | 241 | |
22e2c507 JA |
242 | /* |
243 | * idle window management | |
244 | */ | |
245 | struct timer_list idle_slice_timer; | |
23e018a1 | 246 | struct work_struct unplug_work; |
1da177e4 | 247 | |
22e2c507 JA |
248 | struct cfq_queue *active_queue; |
249 | struct cfq_io_context *active_cic; | |
22e2c507 | 250 | |
c2dea2d1 VT |
251 | /* |
252 | * async queue for each priority case | |
253 | */ | |
254 | struct cfq_queue *async_cfqq[2][IOPRIO_BE_NR]; | |
255 | struct cfq_queue *async_idle_cfqq; | |
15c31be4 | 256 | |
6d048f53 | 257 | sector_t last_position; |
1da177e4 | 258 | |
1da177e4 LT |
259 | /* |
260 | * tunables, see top of file | |
261 | */ | |
262 | unsigned int cfq_quantum; | |
22e2c507 | 263 | unsigned int cfq_fifo_expire[2]; |
1da177e4 LT |
264 | unsigned int cfq_back_penalty; |
265 | unsigned int cfq_back_max; | |
22e2c507 JA |
266 | unsigned int cfq_slice[2]; |
267 | unsigned int cfq_slice_async_rq; | |
268 | unsigned int cfq_slice_idle; | |
963b72fc | 269 | unsigned int cfq_latency; |
ae30c286 | 270 | unsigned int cfq_group_isolation; |
d9ff4187 AV |
271 | |
272 | struct list_head cic_list; | |
1da177e4 | 273 | |
6118b70b JA |
274 | /* |
275 | * Fallback dummy cfqq for extreme OOM conditions | |
276 | */ | |
277 | struct cfq_queue oom_cfqq; | |
365722bb | 278 | |
573412b2 | 279 | unsigned long last_delayed_sync; |
25fb5169 VG |
280 | |
281 | /* List of cfq groups being managed on this device*/ | |
282 | struct hlist_head cfqg_list; | |
bb729bc9 | 283 | struct rcu_head rcu; |
1da177e4 LT |
284 | }; |
285 | ||
25fb5169 VG |
286 | static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd); |
287 | ||
cdb16e8f VG |
288 | static struct cfq_rb_root *service_tree_for(struct cfq_group *cfqg, |
289 | enum wl_prio_t prio, | |
65b32a57 | 290 | enum wl_type_t type) |
c0324a02 | 291 | { |
1fa8f6d6 VG |
292 | if (!cfqg) |
293 | return NULL; | |
294 | ||
c0324a02 | 295 | if (prio == IDLE_WORKLOAD) |
cdb16e8f | 296 | return &cfqg->service_tree_idle; |
c0324a02 | 297 | |
cdb16e8f | 298 | return &cfqg->service_trees[prio][type]; |
c0324a02 CZ |
299 | } |
300 | ||
3b18152c | 301 | enum cfqq_state_flags { |
b0b8d749 JA |
302 | CFQ_CFQQ_FLAG_on_rr = 0, /* on round-robin busy list */ |
303 | CFQ_CFQQ_FLAG_wait_request, /* waiting for a request */ | |
b029195d | 304 | CFQ_CFQQ_FLAG_must_dispatch, /* must be allowed a dispatch */ |
b0b8d749 | 305 | CFQ_CFQQ_FLAG_must_alloc_slice, /* per-slice must_alloc flag */ |
b0b8d749 JA |
306 | CFQ_CFQQ_FLAG_fifo_expire, /* FIFO checked in this slice */ |
307 | CFQ_CFQQ_FLAG_idle_window, /* slice idling enabled */ | |
308 | CFQ_CFQQ_FLAG_prio_changed, /* task priority has changed */ | |
44f7c160 | 309 | CFQ_CFQQ_FLAG_slice_new, /* no requests dispatched in slice */ |
91fac317 | 310 | CFQ_CFQQ_FLAG_sync, /* synchronous queue */ |
b3b6d040 | 311 | CFQ_CFQQ_FLAG_coop, /* cfqq is shared */ |
ae54abed | 312 | CFQ_CFQQ_FLAG_split_coop, /* shared cfqq will be splitted */ |
76280aff | 313 | CFQ_CFQQ_FLAG_deep, /* sync cfqq experienced large depth */ |
f75edf2d | 314 | CFQ_CFQQ_FLAG_wait_busy, /* Waiting for next request */ |
3b18152c JA |
315 | }; |
316 | ||
317 | #define CFQ_CFQQ_FNS(name) \ | |
318 | static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \ | |
319 | { \ | |
fe094d98 | 320 | (cfqq)->flags |= (1 << CFQ_CFQQ_FLAG_##name); \ |
3b18152c JA |
321 | } \ |
322 | static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \ | |
323 | { \ | |
fe094d98 | 324 | (cfqq)->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \ |
3b18152c JA |
325 | } \ |
326 | static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \ | |
327 | { \ | |
fe094d98 | 328 | return ((cfqq)->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \ |
3b18152c JA |
329 | } |
330 | ||
331 | CFQ_CFQQ_FNS(on_rr); | |
332 | CFQ_CFQQ_FNS(wait_request); | |
b029195d | 333 | CFQ_CFQQ_FNS(must_dispatch); |
3b18152c | 334 | CFQ_CFQQ_FNS(must_alloc_slice); |
3b18152c JA |
335 | CFQ_CFQQ_FNS(fifo_expire); |
336 | CFQ_CFQQ_FNS(idle_window); | |
337 | CFQ_CFQQ_FNS(prio_changed); | |
44f7c160 | 338 | CFQ_CFQQ_FNS(slice_new); |
91fac317 | 339 | CFQ_CFQQ_FNS(sync); |
a36e71f9 | 340 | CFQ_CFQQ_FNS(coop); |
ae54abed | 341 | CFQ_CFQQ_FNS(split_coop); |
76280aff | 342 | CFQ_CFQQ_FNS(deep); |
f75edf2d | 343 | CFQ_CFQQ_FNS(wait_busy); |
3b18152c JA |
344 | #undef CFQ_CFQQ_FNS |
345 | ||
2868ef7b VG |
346 | #ifdef CONFIG_DEBUG_CFQ_IOSCHED |
347 | #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \ | |
348 | blk_add_trace_msg((cfqd)->queue, "cfq%d%c %s " fmt, (cfqq)->pid, \ | |
349 | cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \ | |
350 | blkg_path(&(cfqq)->cfqg->blkg), ##args); | |
351 | ||
352 | #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) \ | |
353 | blk_add_trace_msg((cfqd)->queue, "%s " fmt, \ | |
354 | blkg_path(&(cfqg)->blkg), ##args); \ | |
355 | ||
356 | #else | |
7b679138 JA |
357 | #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \ |
358 | blk_add_trace_msg((cfqd)->queue, "cfq%d " fmt, (cfqq)->pid, ##args) | |
2868ef7b VG |
359 | #define cfq_log_cfqg(cfqd, cfqg, fmt, args...) do {} while (0); |
360 | #endif | |
7b679138 JA |
361 | #define cfq_log(cfqd, fmt, args...) \ |
362 | blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args) | |
363 | ||
615f0259 VG |
364 | /* Traverses through cfq group service trees */ |
365 | #define for_each_cfqg_st(cfqg, i, j, st) \ | |
366 | for (i = 0; i <= IDLE_WORKLOAD; i++) \ | |
367 | for (j = 0, st = i < IDLE_WORKLOAD ? &cfqg->service_trees[i][j]\ | |
368 | : &cfqg->service_tree_idle; \ | |
369 | (i < IDLE_WORKLOAD && j <= SYNC_WORKLOAD) || \ | |
370 | (i == IDLE_WORKLOAD && j == 0); \ | |
371 | j++, st = i < IDLE_WORKLOAD ? \ | |
372 | &cfqg->service_trees[i][j]: NULL) \ | |
373 | ||
374 | ||
c0324a02 CZ |
375 | static inline enum wl_prio_t cfqq_prio(struct cfq_queue *cfqq) |
376 | { | |
377 | if (cfq_class_idle(cfqq)) | |
378 | return IDLE_WORKLOAD; | |
379 | if (cfq_class_rt(cfqq)) | |
380 | return RT_WORKLOAD; | |
381 | return BE_WORKLOAD; | |
382 | } | |
383 | ||
718eee05 CZ |
384 | |
385 | static enum wl_type_t cfqq_type(struct cfq_queue *cfqq) | |
386 | { | |
387 | if (!cfq_cfqq_sync(cfqq)) | |
388 | return ASYNC_WORKLOAD; | |
389 | if (!cfq_cfqq_idle_window(cfqq)) | |
390 | return SYNC_NOIDLE_WORKLOAD; | |
391 | return SYNC_WORKLOAD; | |
392 | } | |
393 | ||
58ff82f3 VG |
394 | static inline int cfq_group_busy_queues_wl(enum wl_prio_t wl, |
395 | struct cfq_data *cfqd, | |
396 | struct cfq_group *cfqg) | |
c0324a02 CZ |
397 | { |
398 | if (wl == IDLE_WORKLOAD) | |
cdb16e8f | 399 | return cfqg->service_tree_idle.count; |
c0324a02 | 400 | |
cdb16e8f VG |
401 | return cfqg->service_trees[wl][ASYNC_WORKLOAD].count |
402 | + cfqg->service_trees[wl][SYNC_NOIDLE_WORKLOAD].count | |
403 | + cfqg->service_trees[wl][SYNC_WORKLOAD].count; | |
c0324a02 CZ |
404 | } |
405 | ||
f26bd1f0 VG |
406 | static inline int cfqg_busy_async_queues(struct cfq_data *cfqd, |
407 | struct cfq_group *cfqg) | |
408 | { | |
409 | return cfqg->service_trees[RT_WORKLOAD][ASYNC_WORKLOAD].count | |
410 | + cfqg->service_trees[BE_WORKLOAD][ASYNC_WORKLOAD].count; | |
411 | } | |
412 | ||
165125e1 | 413 | static void cfq_dispatch_insert(struct request_queue *, struct request *); |
a6151c3a | 414 | static struct cfq_queue *cfq_get_queue(struct cfq_data *, bool, |
fd0928df | 415 | struct io_context *, gfp_t); |
4ac845a2 | 416 | static struct cfq_io_context *cfq_cic_lookup(struct cfq_data *, |
91fac317 VT |
417 | struct io_context *); |
418 | ||
419 | static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_context *cic, | |
a6151c3a | 420 | bool is_sync) |
91fac317 | 421 | { |
a6151c3a | 422 | return cic->cfqq[is_sync]; |
91fac317 VT |
423 | } |
424 | ||
425 | static inline void cic_set_cfqq(struct cfq_io_context *cic, | |
a6151c3a | 426 | struct cfq_queue *cfqq, bool is_sync) |
91fac317 | 427 | { |
a6151c3a | 428 | cic->cfqq[is_sync] = cfqq; |
91fac317 VT |
429 | } |
430 | ||
431 | /* | |
432 | * We regard a request as SYNC, if it's either a read or has the SYNC bit | |
433 | * set (in which case it could also be direct WRITE). | |
434 | */ | |
a6151c3a | 435 | static inline bool cfq_bio_sync(struct bio *bio) |
91fac317 | 436 | { |
a6151c3a | 437 | return bio_data_dir(bio) == READ || bio_rw_flagged(bio, BIO_RW_SYNCIO); |
91fac317 | 438 | } |
1da177e4 | 439 | |
99f95e52 AM |
440 | /* |
441 | * scheduler run of queue, if there are requests pending and no one in the | |
442 | * driver that will restart queueing | |
443 | */ | |
23e018a1 | 444 | static inline void cfq_schedule_dispatch(struct cfq_data *cfqd) |
99f95e52 | 445 | { |
7b679138 JA |
446 | if (cfqd->busy_queues) { |
447 | cfq_log(cfqd, "schedule dispatch"); | |
23e018a1 | 448 | kblockd_schedule_work(cfqd->queue, &cfqd->unplug_work); |
7b679138 | 449 | } |
99f95e52 AM |
450 | } |
451 | ||
165125e1 | 452 | static int cfq_queue_empty(struct request_queue *q) |
99f95e52 AM |
453 | { |
454 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
455 | ||
f04a6424 | 456 | return !cfqd->rq_queued; |
99f95e52 AM |
457 | } |
458 | ||
44f7c160 JA |
459 | /* |
460 | * Scale schedule slice based on io priority. Use the sync time slice only | |
461 | * if a queue is marked sync and has sync io queued. A sync queue with async | |
462 | * io only, should not get full sync slice length. | |
463 | */ | |
a6151c3a | 464 | static inline int cfq_prio_slice(struct cfq_data *cfqd, bool sync, |
d9e7620e | 465 | unsigned short prio) |
44f7c160 | 466 | { |
d9e7620e | 467 | const int base_slice = cfqd->cfq_slice[sync]; |
44f7c160 | 468 | |
d9e7620e JA |
469 | WARN_ON(prio >= IOPRIO_BE_NR); |
470 | ||
471 | return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - prio)); | |
472 | } | |
44f7c160 | 473 | |
d9e7620e JA |
474 | static inline int |
475 | cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
476 | { | |
477 | return cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio); | |
44f7c160 JA |
478 | } |
479 | ||
25bc6b07 VG |
480 | static inline u64 cfq_scale_slice(unsigned long delta, struct cfq_group *cfqg) |
481 | { | |
482 | u64 d = delta << CFQ_SERVICE_SHIFT; | |
483 | ||
484 | d = d * BLKIO_WEIGHT_DEFAULT; | |
485 | do_div(d, cfqg->weight); | |
486 | return d; | |
487 | } | |
488 | ||
489 | static inline u64 max_vdisktime(u64 min_vdisktime, u64 vdisktime) | |
490 | { | |
491 | s64 delta = (s64)(vdisktime - min_vdisktime); | |
492 | if (delta > 0) | |
493 | min_vdisktime = vdisktime; | |
494 | ||
495 | return min_vdisktime; | |
496 | } | |
497 | ||
498 | static inline u64 min_vdisktime(u64 min_vdisktime, u64 vdisktime) | |
499 | { | |
500 | s64 delta = (s64)(vdisktime - min_vdisktime); | |
501 | if (delta < 0) | |
502 | min_vdisktime = vdisktime; | |
503 | ||
504 | return min_vdisktime; | |
505 | } | |
506 | ||
507 | static void update_min_vdisktime(struct cfq_rb_root *st) | |
508 | { | |
509 | u64 vdisktime = st->min_vdisktime; | |
510 | struct cfq_group *cfqg; | |
511 | ||
512 | if (st->active) { | |
513 | cfqg = rb_entry_cfqg(st->active); | |
514 | vdisktime = cfqg->vdisktime; | |
515 | } | |
516 | ||
517 | if (st->left) { | |
518 | cfqg = rb_entry_cfqg(st->left); | |
519 | vdisktime = min_vdisktime(vdisktime, cfqg->vdisktime); | |
520 | } | |
521 | ||
522 | st->min_vdisktime = max_vdisktime(st->min_vdisktime, vdisktime); | |
523 | } | |
524 | ||
5db5d642 CZ |
525 | /* |
526 | * get averaged number of queues of RT/BE priority. | |
527 | * average is updated, with a formula that gives more weight to higher numbers, | |
528 | * to quickly follows sudden increases and decrease slowly | |
529 | */ | |
530 | ||
58ff82f3 VG |
531 | static inline unsigned cfq_group_get_avg_queues(struct cfq_data *cfqd, |
532 | struct cfq_group *cfqg, bool rt) | |
5869619c | 533 | { |
5db5d642 CZ |
534 | unsigned min_q, max_q; |
535 | unsigned mult = cfq_hist_divisor - 1; | |
536 | unsigned round = cfq_hist_divisor / 2; | |
58ff82f3 | 537 | unsigned busy = cfq_group_busy_queues_wl(rt, cfqd, cfqg); |
5db5d642 | 538 | |
58ff82f3 VG |
539 | min_q = min(cfqg->busy_queues_avg[rt], busy); |
540 | max_q = max(cfqg->busy_queues_avg[rt], busy); | |
541 | cfqg->busy_queues_avg[rt] = (mult * max_q + min_q + round) / | |
5db5d642 | 542 | cfq_hist_divisor; |
58ff82f3 VG |
543 | return cfqg->busy_queues_avg[rt]; |
544 | } | |
545 | ||
546 | static inline unsigned | |
547 | cfq_group_slice(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
548 | { | |
549 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
550 | ||
551 | return cfq_target_latency * cfqg->weight / st->total_weight; | |
5db5d642 CZ |
552 | } |
553 | ||
44f7c160 JA |
554 | static inline void |
555 | cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
556 | { | |
5db5d642 CZ |
557 | unsigned slice = cfq_prio_to_slice(cfqd, cfqq); |
558 | if (cfqd->cfq_latency) { | |
58ff82f3 VG |
559 | /* |
560 | * interested queues (we consider only the ones with the same | |
561 | * priority class in the cfq group) | |
562 | */ | |
563 | unsigned iq = cfq_group_get_avg_queues(cfqd, cfqq->cfqg, | |
564 | cfq_class_rt(cfqq)); | |
5db5d642 CZ |
565 | unsigned sync_slice = cfqd->cfq_slice[1]; |
566 | unsigned expect_latency = sync_slice * iq; | |
58ff82f3 VG |
567 | unsigned group_slice = cfq_group_slice(cfqd, cfqq->cfqg); |
568 | ||
569 | if (expect_latency > group_slice) { | |
5db5d642 CZ |
570 | unsigned base_low_slice = 2 * cfqd->cfq_slice_idle; |
571 | /* scale low_slice according to IO priority | |
572 | * and sync vs async */ | |
573 | unsigned low_slice = | |
574 | min(slice, base_low_slice * slice / sync_slice); | |
575 | /* the adapted slice value is scaled to fit all iqs | |
576 | * into the target latency */ | |
58ff82f3 | 577 | slice = max(slice * group_slice / expect_latency, |
5db5d642 CZ |
578 | low_slice); |
579 | } | |
580 | } | |
dae739eb | 581 | cfqq->slice_start = jiffies; |
5db5d642 | 582 | cfqq->slice_end = jiffies + slice; |
f75edf2d | 583 | cfqq->allocated_slice = slice; |
7b679138 | 584 | cfq_log_cfqq(cfqd, cfqq, "set_slice=%lu", cfqq->slice_end - jiffies); |
44f7c160 JA |
585 | } |
586 | ||
587 | /* | |
588 | * We need to wrap this check in cfq_cfqq_slice_new(), since ->slice_end | |
589 | * isn't valid until the first request from the dispatch is activated | |
590 | * and the slice time set. | |
591 | */ | |
a6151c3a | 592 | static inline bool cfq_slice_used(struct cfq_queue *cfqq) |
44f7c160 JA |
593 | { |
594 | if (cfq_cfqq_slice_new(cfqq)) | |
595 | return 0; | |
596 | if (time_before(jiffies, cfqq->slice_end)) | |
597 | return 0; | |
598 | ||
599 | return 1; | |
600 | } | |
601 | ||
1da177e4 | 602 | /* |
5e705374 | 603 | * Lifted from AS - choose which of rq1 and rq2 that is best served now. |
1da177e4 | 604 | * We choose the request that is closest to the head right now. Distance |
e8a99053 | 605 | * behind the head is penalized and only allowed to a certain extent. |
1da177e4 | 606 | */ |
5e705374 | 607 | static struct request * |
cf7c25cf | 608 | cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2, sector_t last) |
1da177e4 | 609 | { |
cf7c25cf | 610 | sector_t s1, s2, d1 = 0, d2 = 0; |
1da177e4 | 611 | unsigned long back_max; |
e8a99053 AM |
612 | #define CFQ_RQ1_WRAP 0x01 /* request 1 wraps */ |
613 | #define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */ | |
614 | unsigned wrap = 0; /* bit mask: requests behind the disk head? */ | |
1da177e4 | 615 | |
5e705374 JA |
616 | if (rq1 == NULL || rq1 == rq2) |
617 | return rq2; | |
618 | if (rq2 == NULL) | |
619 | return rq1; | |
9c2c38a1 | 620 | |
5e705374 JA |
621 | if (rq_is_sync(rq1) && !rq_is_sync(rq2)) |
622 | return rq1; | |
623 | else if (rq_is_sync(rq2) && !rq_is_sync(rq1)) | |
624 | return rq2; | |
374f84ac JA |
625 | if (rq_is_meta(rq1) && !rq_is_meta(rq2)) |
626 | return rq1; | |
627 | else if (rq_is_meta(rq2) && !rq_is_meta(rq1)) | |
628 | return rq2; | |
1da177e4 | 629 | |
83096ebf TH |
630 | s1 = blk_rq_pos(rq1); |
631 | s2 = blk_rq_pos(rq2); | |
1da177e4 | 632 | |
1da177e4 LT |
633 | /* |
634 | * by definition, 1KiB is 2 sectors | |
635 | */ | |
636 | back_max = cfqd->cfq_back_max * 2; | |
637 | ||
638 | /* | |
639 | * Strict one way elevator _except_ in the case where we allow | |
640 | * short backward seeks which are biased as twice the cost of a | |
641 | * similar forward seek. | |
642 | */ | |
643 | if (s1 >= last) | |
644 | d1 = s1 - last; | |
645 | else if (s1 + back_max >= last) | |
646 | d1 = (last - s1) * cfqd->cfq_back_penalty; | |
647 | else | |
e8a99053 | 648 | wrap |= CFQ_RQ1_WRAP; |
1da177e4 LT |
649 | |
650 | if (s2 >= last) | |
651 | d2 = s2 - last; | |
652 | else if (s2 + back_max >= last) | |
653 | d2 = (last - s2) * cfqd->cfq_back_penalty; | |
654 | else | |
e8a99053 | 655 | wrap |= CFQ_RQ2_WRAP; |
1da177e4 LT |
656 | |
657 | /* Found required data */ | |
e8a99053 AM |
658 | |
659 | /* | |
660 | * By doing switch() on the bit mask "wrap" we avoid having to | |
661 | * check two variables for all permutations: --> faster! | |
662 | */ | |
663 | switch (wrap) { | |
5e705374 | 664 | case 0: /* common case for CFQ: rq1 and rq2 not wrapped */ |
e8a99053 | 665 | if (d1 < d2) |
5e705374 | 666 | return rq1; |
e8a99053 | 667 | else if (d2 < d1) |
5e705374 | 668 | return rq2; |
e8a99053 AM |
669 | else { |
670 | if (s1 >= s2) | |
5e705374 | 671 | return rq1; |
e8a99053 | 672 | else |
5e705374 | 673 | return rq2; |
e8a99053 | 674 | } |
1da177e4 | 675 | |
e8a99053 | 676 | case CFQ_RQ2_WRAP: |
5e705374 | 677 | return rq1; |
e8a99053 | 678 | case CFQ_RQ1_WRAP: |
5e705374 JA |
679 | return rq2; |
680 | case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both rqs wrapped */ | |
e8a99053 AM |
681 | default: |
682 | /* | |
683 | * Since both rqs are wrapped, | |
684 | * start with the one that's further behind head | |
685 | * (--> only *one* back seek required), | |
686 | * since back seek takes more time than forward. | |
687 | */ | |
688 | if (s1 <= s2) | |
5e705374 | 689 | return rq1; |
1da177e4 | 690 | else |
5e705374 | 691 | return rq2; |
1da177e4 LT |
692 | } |
693 | } | |
694 | ||
498d3aa2 JA |
695 | /* |
696 | * The below is leftmost cache rbtree addon | |
697 | */ | |
0871714e | 698 | static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root) |
cc09e299 | 699 | { |
615f0259 VG |
700 | /* Service tree is empty */ |
701 | if (!root->count) | |
702 | return NULL; | |
703 | ||
cc09e299 JA |
704 | if (!root->left) |
705 | root->left = rb_first(&root->rb); | |
706 | ||
0871714e JA |
707 | if (root->left) |
708 | return rb_entry(root->left, struct cfq_queue, rb_node); | |
709 | ||
710 | return NULL; | |
cc09e299 JA |
711 | } |
712 | ||
1fa8f6d6 VG |
713 | static struct cfq_group *cfq_rb_first_group(struct cfq_rb_root *root) |
714 | { | |
715 | if (!root->left) | |
716 | root->left = rb_first(&root->rb); | |
717 | ||
718 | if (root->left) | |
719 | return rb_entry_cfqg(root->left); | |
720 | ||
721 | return NULL; | |
722 | } | |
723 | ||
a36e71f9 JA |
724 | static void rb_erase_init(struct rb_node *n, struct rb_root *root) |
725 | { | |
726 | rb_erase(n, root); | |
727 | RB_CLEAR_NODE(n); | |
728 | } | |
729 | ||
cc09e299 JA |
730 | static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root) |
731 | { | |
732 | if (root->left == n) | |
733 | root->left = NULL; | |
a36e71f9 | 734 | rb_erase_init(n, &root->rb); |
aa6f6a3d | 735 | --root->count; |
cc09e299 JA |
736 | } |
737 | ||
1da177e4 LT |
738 | /* |
739 | * would be nice to take fifo expire time into account as well | |
740 | */ | |
5e705374 JA |
741 | static struct request * |
742 | cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
743 | struct request *last) | |
1da177e4 | 744 | { |
21183b07 JA |
745 | struct rb_node *rbnext = rb_next(&last->rb_node); |
746 | struct rb_node *rbprev = rb_prev(&last->rb_node); | |
5e705374 | 747 | struct request *next = NULL, *prev = NULL; |
1da177e4 | 748 | |
21183b07 | 749 | BUG_ON(RB_EMPTY_NODE(&last->rb_node)); |
1da177e4 LT |
750 | |
751 | if (rbprev) | |
5e705374 | 752 | prev = rb_entry_rq(rbprev); |
1da177e4 | 753 | |
21183b07 | 754 | if (rbnext) |
5e705374 | 755 | next = rb_entry_rq(rbnext); |
21183b07 JA |
756 | else { |
757 | rbnext = rb_first(&cfqq->sort_list); | |
758 | if (rbnext && rbnext != &last->rb_node) | |
5e705374 | 759 | next = rb_entry_rq(rbnext); |
21183b07 | 760 | } |
1da177e4 | 761 | |
cf7c25cf | 762 | return cfq_choose_req(cfqd, next, prev, blk_rq_pos(last)); |
1da177e4 LT |
763 | } |
764 | ||
d9e7620e JA |
765 | static unsigned long cfq_slice_offset(struct cfq_data *cfqd, |
766 | struct cfq_queue *cfqq) | |
1da177e4 | 767 | { |
d9e7620e JA |
768 | /* |
769 | * just an approximation, should be ok. | |
770 | */ | |
cdb16e8f | 771 | return (cfqq->cfqg->nr_cfqq - 1) * (cfq_prio_slice(cfqd, 1, 0) - |
464191c6 | 772 | cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio)); |
d9e7620e JA |
773 | } |
774 | ||
1fa8f6d6 VG |
775 | static inline s64 |
776 | cfqg_key(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
777 | { | |
778 | return cfqg->vdisktime - st->min_vdisktime; | |
779 | } | |
780 | ||
781 | static void | |
782 | __cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg) | |
783 | { | |
784 | struct rb_node **node = &st->rb.rb_node; | |
785 | struct rb_node *parent = NULL; | |
786 | struct cfq_group *__cfqg; | |
787 | s64 key = cfqg_key(st, cfqg); | |
788 | int left = 1; | |
789 | ||
790 | while (*node != NULL) { | |
791 | parent = *node; | |
792 | __cfqg = rb_entry_cfqg(parent); | |
793 | ||
794 | if (key < cfqg_key(st, __cfqg)) | |
795 | node = &parent->rb_left; | |
796 | else { | |
797 | node = &parent->rb_right; | |
798 | left = 0; | |
799 | } | |
800 | } | |
801 | ||
802 | if (left) | |
803 | st->left = &cfqg->rb_node; | |
804 | ||
805 | rb_link_node(&cfqg->rb_node, parent, node); | |
806 | rb_insert_color(&cfqg->rb_node, &st->rb); | |
807 | } | |
808 | ||
809 | static void | |
810 | cfq_group_service_tree_add(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
811 | { | |
812 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
813 | struct cfq_group *__cfqg; | |
814 | struct rb_node *n; | |
815 | ||
816 | cfqg->nr_cfqq++; | |
817 | if (cfqg->on_st) | |
818 | return; | |
819 | ||
820 | /* | |
821 | * Currently put the group at the end. Later implement something | |
822 | * so that groups get lesser vtime based on their weights, so that | |
823 | * if group does not loose all if it was not continously backlogged. | |
824 | */ | |
825 | n = rb_last(&st->rb); | |
826 | if (n) { | |
827 | __cfqg = rb_entry_cfqg(n); | |
828 | cfqg->vdisktime = __cfqg->vdisktime + CFQ_IDLE_DELAY; | |
829 | } else | |
830 | cfqg->vdisktime = st->min_vdisktime; | |
831 | ||
832 | __cfq_group_service_tree_add(st, cfqg); | |
833 | cfqg->on_st = true; | |
58ff82f3 | 834 | st->total_weight += cfqg->weight; |
1fa8f6d6 VG |
835 | } |
836 | ||
837 | static void | |
838 | cfq_group_service_tree_del(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
839 | { | |
840 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
841 | ||
25bc6b07 VG |
842 | if (st->active == &cfqg->rb_node) |
843 | st->active = NULL; | |
844 | ||
1fa8f6d6 VG |
845 | BUG_ON(cfqg->nr_cfqq < 1); |
846 | cfqg->nr_cfqq--; | |
25bc6b07 | 847 | |
1fa8f6d6 VG |
848 | /* If there are other cfq queues under this group, don't delete it */ |
849 | if (cfqg->nr_cfqq) | |
850 | return; | |
851 | ||
2868ef7b | 852 | cfq_log_cfqg(cfqd, cfqg, "del_from_rr group"); |
1fa8f6d6 | 853 | cfqg->on_st = false; |
58ff82f3 | 854 | st->total_weight -= cfqg->weight; |
1fa8f6d6 VG |
855 | if (!RB_EMPTY_NODE(&cfqg->rb_node)) |
856 | cfq_rb_erase(&cfqg->rb_node, st); | |
dae739eb | 857 | cfqg->saved_workload_slice = 0; |
9195291e | 858 | blkiocg_update_dequeue_stats(&cfqg->blkg, 1); |
dae739eb VG |
859 | } |
860 | ||
861 | static inline unsigned int cfq_cfqq_slice_usage(struct cfq_queue *cfqq) | |
862 | { | |
f75edf2d | 863 | unsigned int slice_used; |
dae739eb VG |
864 | |
865 | /* | |
866 | * Queue got expired before even a single request completed or | |
867 | * got expired immediately after first request completion. | |
868 | */ | |
869 | if (!cfqq->slice_start || cfqq->slice_start == jiffies) { | |
870 | /* | |
871 | * Also charge the seek time incurred to the group, otherwise | |
872 | * if there are mutiple queues in the group, each can dispatch | |
873 | * a single request on seeky media and cause lots of seek time | |
874 | * and group will never know it. | |
875 | */ | |
876 | slice_used = max_t(unsigned, (jiffies - cfqq->dispatch_start), | |
877 | 1); | |
878 | } else { | |
879 | slice_used = jiffies - cfqq->slice_start; | |
f75edf2d VG |
880 | if (slice_used > cfqq->allocated_slice) |
881 | slice_used = cfqq->allocated_slice; | |
dae739eb VG |
882 | } |
883 | ||
9a0785b0 | 884 | cfq_log_cfqq(cfqq->cfqd, cfqq, "sl_used=%u", slice_used); |
dae739eb VG |
885 | return slice_used; |
886 | } | |
887 | ||
888 | static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg, | |
812df48d | 889 | struct cfq_queue *cfqq, bool forced) |
dae739eb VG |
890 | { |
891 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
f26bd1f0 VG |
892 | unsigned int used_sl, charge_sl; |
893 | int nr_sync = cfqg->nr_cfqq - cfqg_busy_async_queues(cfqd, cfqg) | |
894 | - cfqg->service_tree_idle.count; | |
895 | ||
896 | BUG_ON(nr_sync < 0); | |
897 | used_sl = charge_sl = cfq_cfqq_slice_usage(cfqq); | |
dae739eb | 898 | |
f26bd1f0 VG |
899 | if (!cfq_cfqq_sync(cfqq) && !nr_sync) |
900 | charge_sl = cfqq->allocated_slice; | |
dae739eb VG |
901 | |
902 | /* Can't update vdisktime while group is on service tree */ | |
903 | cfq_rb_erase(&cfqg->rb_node, st); | |
f26bd1f0 | 904 | cfqg->vdisktime += cfq_scale_slice(charge_sl, cfqg); |
dae739eb VG |
905 | __cfq_group_service_tree_add(st, cfqg); |
906 | ||
907 | /* This group is being expired. Save the context */ | |
908 | if (time_after(cfqd->workload_expires, jiffies)) { | |
909 | cfqg->saved_workload_slice = cfqd->workload_expires | |
910 | - jiffies; | |
911 | cfqg->saved_workload = cfqd->serving_type; | |
912 | cfqg->saved_serving_prio = cfqd->serving_prio; | |
913 | } else | |
914 | cfqg->saved_workload_slice = 0; | |
2868ef7b VG |
915 | |
916 | cfq_log_cfqg(cfqd, cfqg, "served: vt=%llu min_vt=%llu", cfqg->vdisktime, | |
917 | st->min_vdisktime); | |
303a3acb | 918 | blkiocg_update_timeslice_used(&cfqg->blkg, used_sl); |
812df48d | 919 | blkiocg_set_start_empty_time(&cfqg->blkg, forced); |
1fa8f6d6 VG |
920 | } |
921 | ||
25fb5169 VG |
922 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
923 | static inline struct cfq_group *cfqg_of_blkg(struct blkio_group *blkg) | |
924 | { | |
925 | if (blkg) | |
926 | return container_of(blkg, struct cfq_group, blkg); | |
927 | return NULL; | |
928 | } | |
929 | ||
f8d461d6 VG |
930 | void |
931 | cfq_update_blkio_group_weight(struct blkio_group *blkg, unsigned int weight) | |
932 | { | |
933 | cfqg_of_blkg(blkg)->weight = weight; | |
934 | } | |
935 | ||
25fb5169 VG |
936 | static struct cfq_group * |
937 | cfq_find_alloc_cfqg(struct cfq_data *cfqd, struct cgroup *cgroup, int create) | |
938 | { | |
939 | struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup); | |
940 | struct cfq_group *cfqg = NULL; | |
941 | void *key = cfqd; | |
942 | int i, j; | |
943 | struct cfq_rb_root *st; | |
22084190 VG |
944 | struct backing_dev_info *bdi = &cfqd->queue->backing_dev_info; |
945 | unsigned int major, minor; | |
25fb5169 | 946 | |
25fb5169 VG |
947 | cfqg = cfqg_of_blkg(blkiocg_lookup_group(blkcg, key)); |
948 | if (cfqg || !create) | |
949 | goto done; | |
950 | ||
951 | cfqg = kzalloc_node(sizeof(*cfqg), GFP_ATOMIC, cfqd->queue->node); | |
952 | if (!cfqg) | |
953 | goto done; | |
954 | ||
955 | cfqg->weight = blkcg->weight; | |
956 | for_each_cfqg_st(cfqg, i, j, st) | |
957 | *st = CFQ_RB_ROOT; | |
958 | RB_CLEAR_NODE(&cfqg->rb_node); | |
84c124da | 959 | blkio_group_init(&cfqg->blkg); |
25fb5169 | 960 | |
b1c35769 VG |
961 | /* |
962 | * Take the initial reference that will be released on destroy | |
963 | * This can be thought of a joint reference by cgroup and | |
964 | * elevator which will be dropped by either elevator exit | |
965 | * or cgroup deletion path depending on who is exiting first. | |
966 | */ | |
967 | atomic_set(&cfqg->ref, 1); | |
968 | ||
25fb5169 | 969 | /* Add group onto cgroup list */ |
22084190 VG |
970 | sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor); |
971 | blkiocg_add_blkio_group(blkcg, &cfqg->blkg, (void *)cfqd, | |
972 | MKDEV(major, minor)); | |
25fb5169 VG |
973 | |
974 | /* Add group on cfqd list */ | |
975 | hlist_add_head(&cfqg->cfqd_node, &cfqd->cfqg_list); | |
976 | ||
977 | done: | |
25fb5169 VG |
978 | return cfqg; |
979 | } | |
980 | ||
981 | /* | |
982 | * Search for the cfq group current task belongs to. If create = 1, then also | |
983 | * create the cfq group if it does not exist. request_queue lock must be held. | |
984 | */ | |
985 | static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd, int create) | |
986 | { | |
987 | struct cgroup *cgroup; | |
988 | struct cfq_group *cfqg = NULL; | |
989 | ||
990 | rcu_read_lock(); | |
991 | cgroup = task_cgroup(current, blkio_subsys_id); | |
992 | cfqg = cfq_find_alloc_cfqg(cfqd, cgroup, create); | |
993 | if (!cfqg && create) | |
994 | cfqg = &cfqd->root_group; | |
995 | rcu_read_unlock(); | |
996 | return cfqg; | |
997 | } | |
998 | ||
999 | static void cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) | |
1000 | { | |
1001 | /* Currently, all async queues are mapped to root group */ | |
1002 | if (!cfq_cfqq_sync(cfqq)) | |
1003 | cfqg = &cfqq->cfqd->root_group; | |
1004 | ||
1005 | cfqq->cfqg = cfqg; | |
b1c35769 VG |
1006 | /* cfqq reference on cfqg */ |
1007 | atomic_inc(&cfqq->cfqg->ref); | |
1008 | } | |
1009 | ||
1010 | static void cfq_put_cfqg(struct cfq_group *cfqg) | |
1011 | { | |
1012 | struct cfq_rb_root *st; | |
1013 | int i, j; | |
1014 | ||
1015 | BUG_ON(atomic_read(&cfqg->ref) <= 0); | |
1016 | if (!atomic_dec_and_test(&cfqg->ref)) | |
1017 | return; | |
1018 | for_each_cfqg_st(cfqg, i, j, st) | |
1019 | BUG_ON(!RB_EMPTY_ROOT(&st->rb) || st->active != NULL); | |
1020 | kfree(cfqg); | |
1021 | } | |
1022 | ||
1023 | static void cfq_destroy_cfqg(struct cfq_data *cfqd, struct cfq_group *cfqg) | |
1024 | { | |
1025 | /* Something wrong if we are trying to remove same group twice */ | |
1026 | BUG_ON(hlist_unhashed(&cfqg->cfqd_node)); | |
1027 | ||
1028 | hlist_del_init(&cfqg->cfqd_node); | |
1029 | ||
1030 | /* | |
1031 | * Put the reference taken at the time of creation so that when all | |
1032 | * queues are gone, group can be destroyed. | |
1033 | */ | |
1034 | cfq_put_cfqg(cfqg); | |
1035 | } | |
1036 | ||
1037 | static void cfq_release_cfq_groups(struct cfq_data *cfqd) | |
1038 | { | |
1039 | struct hlist_node *pos, *n; | |
1040 | struct cfq_group *cfqg; | |
1041 | ||
1042 | hlist_for_each_entry_safe(cfqg, pos, n, &cfqd->cfqg_list, cfqd_node) { | |
1043 | /* | |
1044 | * If cgroup removal path got to blk_group first and removed | |
1045 | * it from cgroup list, then it will take care of destroying | |
1046 | * cfqg also. | |
1047 | */ | |
1048 | if (!blkiocg_del_blkio_group(&cfqg->blkg)) | |
1049 | cfq_destroy_cfqg(cfqd, cfqg); | |
1050 | } | |
25fb5169 | 1051 | } |
b1c35769 VG |
1052 | |
1053 | /* | |
1054 | * Blk cgroup controller notification saying that blkio_group object is being | |
1055 | * delinked as associated cgroup object is going away. That also means that | |
1056 | * no new IO will come in this group. So get rid of this group as soon as | |
1057 | * any pending IO in the group is finished. | |
1058 | * | |
1059 | * This function is called under rcu_read_lock(). key is the rcu protected | |
1060 | * pointer. That means "key" is a valid cfq_data pointer as long as we are rcu | |
1061 | * read lock. | |
1062 | * | |
1063 | * "key" was fetched from blkio_group under blkio_cgroup->lock. That means | |
1064 | * it should not be NULL as even if elevator was exiting, cgroup deltion | |
1065 | * path got to it first. | |
1066 | */ | |
1067 | void cfq_unlink_blkio_group(void *key, struct blkio_group *blkg) | |
1068 | { | |
1069 | unsigned long flags; | |
1070 | struct cfq_data *cfqd = key; | |
1071 | ||
1072 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
1073 | cfq_destroy_cfqg(cfqd, cfqg_of_blkg(blkg)); | |
1074 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
1075 | } | |
1076 | ||
25fb5169 VG |
1077 | #else /* GROUP_IOSCHED */ |
1078 | static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd, int create) | |
1079 | { | |
1080 | return &cfqd->root_group; | |
1081 | } | |
1082 | static inline void | |
1083 | cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) { | |
1084 | cfqq->cfqg = cfqg; | |
1085 | } | |
1086 | ||
b1c35769 VG |
1087 | static void cfq_release_cfq_groups(struct cfq_data *cfqd) {} |
1088 | static inline void cfq_put_cfqg(struct cfq_group *cfqg) {} | |
1089 | ||
25fb5169 VG |
1090 | #endif /* GROUP_IOSCHED */ |
1091 | ||
498d3aa2 | 1092 | /* |
c0324a02 | 1093 | * The cfqd->service_trees holds all pending cfq_queue's that have |
498d3aa2 JA |
1094 | * requests waiting to be processed. It is sorted in the order that |
1095 | * we will service the queues. | |
1096 | */ | |
a36e71f9 | 1097 | static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
a6151c3a | 1098 | bool add_front) |
d9e7620e | 1099 | { |
0871714e JA |
1100 | struct rb_node **p, *parent; |
1101 | struct cfq_queue *__cfqq; | |
d9e7620e | 1102 | unsigned long rb_key; |
c0324a02 | 1103 | struct cfq_rb_root *service_tree; |
498d3aa2 | 1104 | int left; |
dae739eb | 1105 | int new_cfqq = 1; |
ae30c286 VG |
1106 | int group_changed = 0; |
1107 | ||
1108 | #ifdef CONFIG_CFQ_GROUP_IOSCHED | |
1109 | if (!cfqd->cfq_group_isolation | |
1110 | && cfqq_type(cfqq) == SYNC_NOIDLE_WORKLOAD | |
1111 | && cfqq->cfqg && cfqq->cfqg != &cfqd->root_group) { | |
1112 | /* Move this cfq to root group */ | |
1113 | cfq_log_cfqq(cfqd, cfqq, "moving to root group"); | |
1114 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) | |
1115 | cfq_group_service_tree_del(cfqd, cfqq->cfqg); | |
1116 | cfqq->orig_cfqg = cfqq->cfqg; | |
1117 | cfqq->cfqg = &cfqd->root_group; | |
1118 | atomic_inc(&cfqd->root_group.ref); | |
1119 | group_changed = 1; | |
1120 | } else if (!cfqd->cfq_group_isolation | |
1121 | && cfqq_type(cfqq) == SYNC_WORKLOAD && cfqq->orig_cfqg) { | |
1122 | /* cfqq is sequential now needs to go to its original group */ | |
1123 | BUG_ON(cfqq->cfqg != &cfqd->root_group); | |
1124 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) | |
1125 | cfq_group_service_tree_del(cfqd, cfqq->cfqg); | |
1126 | cfq_put_cfqg(cfqq->cfqg); | |
1127 | cfqq->cfqg = cfqq->orig_cfqg; | |
1128 | cfqq->orig_cfqg = NULL; | |
1129 | group_changed = 1; | |
1130 | cfq_log_cfqq(cfqd, cfqq, "moved to origin group"); | |
1131 | } | |
1132 | #endif | |
d9e7620e | 1133 | |
cdb16e8f | 1134 | service_tree = service_tree_for(cfqq->cfqg, cfqq_prio(cfqq), |
65b32a57 | 1135 | cfqq_type(cfqq)); |
0871714e JA |
1136 | if (cfq_class_idle(cfqq)) { |
1137 | rb_key = CFQ_IDLE_DELAY; | |
aa6f6a3d | 1138 | parent = rb_last(&service_tree->rb); |
0871714e JA |
1139 | if (parent && parent != &cfqq->rb_node) { |
1140 | __cfqq = rb_entry(parent, struct cfq_queue, rb_node); | |
1141 | rb_key += __cfqq->rb_key; | |
1142 | } else | |
1143 | rb_key += jiffies; | |
1144 | } else if (!add_front) { | |
b9c8946b JA |
1145 | /* |
1146 | * Get our rb key offset. Subtract any residual slice | |
1147 | * value carried from last service. A negative resid | |
1148 | * count indicates slice overrun, and this should position | |
1149 | * the next service time further away in the tree. | |
1150 | */ | |
edd75ffd | 1151 | rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies; |
b9c8946b | 1152 | rb_key -= cfqq->slice_resid; |
edd75ffd | 1153 | cfqq->slice_resid = 0; |
48e025e6 CZ |
1154 | } else { |
1155 | rb_key = -HZ; | |
aa6f6a3d | 1156 | __cfqq = cfq_rb_first(service_tree); |
48e025e6 CZ |
1157 | rb_key += __cfqq ? __cfqq->rb_key : jiffies; |
1158 | } | |
1da177e4 | 1159 | |
d9e7620e | 1160 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) { |
dae739eb | 1161 | new_cfqq = 0; |
99f9628a | 1162 | /* |
d9e7620e | 1163 | * same position, nothing more to do |
99f9628a | 1164 | */ |
c0324a02 CZ |
1165 | if (rb_key == cfqq->rb_key && |
1166 | cfqq->service_tree == service_tree) | |
d9e7620e | 1167 | return; |
1da177e4 | 1168 | |
aa6f6a3d CZ |
1169 | cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree); |
1170 | cfqq->service_tree = NULL; | |
1da177e4 | 1171 | } |
d9e7620e | 1172 | |
498d3aa2 | 1173 | left = 1; |
0871714e | 1174 | parent = NULL; |
aa6f6a3d CZ |
1175 | cfqq->service_tree = service_tree; |
1176 | p = &service_tree->rb.rb_node; | |
d9e7620e | 1177 | while (*p) { |
67060e37 | 1178 | struct rb_node **n; |
cc09e299 | 1179 | |
d9e7620e JA |
1180 | parent = *p; |
1181 | __cfqq = rb_entry(parent, struct cfq_queue, rb_node); | |
1182 | ||
0c534e0a | 1183 | /* |
c0324a02 | 1184 | * sort by key, that represents service time. |
0c534e0a | 1185 | */ |
c0324a02 | 1186 | if (time_before(rb_key, __cfqq->rb_key)) |
67060e37 | 1187 | n = &(*p)->rb_left; |
c0324a02 | 1188 | else { |
67060e37 | 1189 | n = &(*p)->rb_right; |
cc09e299 | 1190 | left = 0; |
c0324a02 | 1191 | } |
67060e37 JA |
1192 | |
1193 | p = n; | |
d9e7620e JA |
1194 | } |
1195 | ||
cc09e299 | 1196 | if (left) |
aa6f6a3d | 1197 | service_tree->left = &cfqq->rb_node; |
cc09e299 | 1198 | |
d9e7620e JA |
1199 | cfqq->rb_key = rb_key; |
1200 | rb_link_node(&cfqq->rb_node, parent, p); | |
aa6f6a3d CZ |
1201 | rb_insert_color(&cfqq->rb_node, &service_tree->rb); |
1202 | service_tree->count++; | |
ae30c286 | 1203 | if ((add_front || !new_cfqq) && !group_changed) |
dae739eb | 1204 | return; |
1fa8f6d6 | 1205 | cfq_group_service_tree_add(cfqd, cfqq->cfqg); |
1da177e4 LT |
1206 | } |
1207 | ||
a36e71f9 | 1208 | static struct cfq_queue * |
f2d1f0ae JA |
1209 | cfq_prio_tree_lookup(struct cfq_data *cfqd, struct rb_root *root, |
1210 | sector_t sector, struct rb_node **ret_parent, | |
1211 | struct rb_node ***rb_link) | |
a36e71f9 | 1212 | { |
a36e71f9 JA |
1213 | struct rb_node **p, *parent; |
1214 | struct cfq_queue *cfqq = NULL; | |
1215 | ||
1216 | parent = NULL; | |
1217 | p = &root->rb_node; | |
1218 | while (*p) { | |
1219 | struct rb_node **n; | |
1220 | ||
1221 | parent = *p; | |
1222 | cfqq = rb_entry(parent, struct cfq_queue, p_node); | |
1223 | ||
1224 | /* | |
1225 | * Sort strictly based on sector. Smallest to the left, | |
1226 | * largest to the right. | |
1227 | */ | |
2e46e8b2 | 1228 | if (sector > blk_rq_pos(cfqq->next_rq)) |
a36e71f9 | 1229 | n = &(*p)->rb_right; |
2e46e8b2 | 1230 | else if (sector < blk_rq_pos(cfqq->next_rq)) |
a36e71f9 JA |
1231 | n = &(*p)->rb_left; |
1232 | else | |
1233 | break; | |
1234 | p = n; | |
3ac6c9f8 | 1235 | cfqq = NULL; |
a36e71f9 JA |
1236 | } |
1237 | ||
1238 | *ret_parent = parent; | |
1239 | if (rb_link) | |
1240 | *rb_link = p; | |
3ac6c9f8 | 1241 | return cfqq; |
a36e71f9 JA |
1242 | } |
1243 | ||
1244 | static void cfq_prio_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1245 | { | |
a36e71f9 JA |
1246 | struct rb_node **p, *parent; |
1247 | struct cfq_queue *__cfqq; | |
1248 | ||
f2d1f0ae JA |
1249 | if (cfqq->p_root) { |
1250 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
1251 | cfqq->p_root = NULL; | |
1252 | } | |
a36e71f9 JA |
1253 | |
1254 | if (cfq_class_idle(cfqq)) | |
1255 | return; | |
1256 | if (!cfqq->next_rq) | |
1257 | return; | |
1258 | ||
f2d1f0ae | 1259 | cfqq->p_root = &cfqd->prio_trees[cfqq->org_ioprio]; |
2e46e8b2 TH |
1260 | __cfqq = cfq_prio_tree_lookup(cfqd, cfqq->p_root, |
1261 | blk_rq_pos(cfqq->next_rq), &parent, &p); | |
3ac6c9f8 JA |
1262 | if (!__cfqq) { |
1263 | rb_link_node(&cfqq->p_node, parent, p); | |
f2d1f0ae JA |
1264 | rb_insert_color(&cfqq->p_node, cfqq->p_root); |
1265 | } else | |
1266 | cfqq->p_root = NULL; | |
a36e71f9 JA |
1267 | } |
1268 | ||
498d3aa2 JA |
1269 | /* |
1270 | * Update cfqq's position in the service tree. | |
1271 | */ | |
edd75ffd | 1272 | static void cfq_resort_rr_list(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
6d048f53 | 1273 | { |
6d048f53 JA |
1274 | /* |
1275 | * Resorting requires the cfqq to be on the RR list already. | |
1276 | */ | |
a36e71f9 | 1277 | if (cfq_cfqq_on_rr(cfqq)) { |
edd75ffd | 1278 | cfq_service_tree_add(cfqd, cfqq, 0); |
a36e71f9 JA |
1279 | cfq_prio_tree_add(cfqd, cfqq); |
1280 | } | |
6d048f53 JA |
1281 | } |
1282 | ||
1da177e4 LT |
1283 | /* |
1284 | * add to busy list of queues for service, trying to be fair in ordering | |
22e2c507 | 1285 | * the pending list according to last request service |
1da177e4 | 1286 | */ |
febffd61 | 1287 | static void cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 1288 | { |
7b679138 | 1289 | cfq_log_cfqq(cfqd, cfqq, "add_to_rr"); |
3b18152c JA |
1290 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
1291 | cfq_mark_cfqq_on_rr(cfqq); | |
1da177e4 LT |
1292 | cfqd->busy_queues++; |
1293 | ||
edd75ffd | 1294 | cfq_resort_rr_list(cfqd, cfqq); |
1da177e4 LT |
1295 | } |
1296 | ||
498d3aa2 JA |
1297 | /* |
1298 | * Called when the cfqq no longer has requests pending, remove it from | |
1299 | * the service tree. | |
1300 | */ | |
febffd61 | 1301 | static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 1302 | { |
7b679138 | 1303 | cfq_log_cfqq(cfqd, cfqq, "del_from_rr"); |
3b18152c JA |
1304 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
1305 | cfq_clear_cfqq_on_rr(cfqq); | |
1da177e4 | 1306 | |
aa6f6a3d CZ |
1307 | if (!RB_EMPTY_NODE(&cfqq->rb_node)) { |
1308 | cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree); | |
1309 | cfqq->service_tree = NULL; | |
1310 | } | |
f2d1f0ae JA |
1311 | if (cfqq->p_root) { |
1312 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
1313 | cfqq->p_root = NULL; | |
1314 | } | |
d9e7620e | 1315 | |
1fa8f6d6 | 1316 | cfq_group_service_tree_del(cfqd, cfqq->cfqg); |
1da177e4 LT |
1317 | BUG_ON(!cfqd->busy_queues); |
1318 | cfqd->busy_queues--; | |
1319 | } | |
1320 | ||
1321 | /* | |
1322 | * rb tree support functions | |
1323 | */ | |
febffd61 | 1324 | static void cfq_del_rq_rb(struct request *rq) |
1da177e4 | 1325 | { |
5e705374 | 1326 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
5e705374 | 1327 | const int sync = rq_is_sync(rq); |
1da177e4 | 1328 | |
b4878f24 JA |
1329 | BUG_ON(!cfqq->queued[sync]); |
1330 | cfqq->queued[sync]--; | |
1da177e4 | 1331 | |
5e705374 | 1332 | elv_rb_del(&cfqq->sort_list, rq); |
1da177e4 | 1333 | |
f04a6424 VG |
1334 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) { |
1335 | /* | |
1336 | * Queue will be deleted from service tree when we actually | |
1337 | * expire it later. Right now just remove it from prio tree | |
1338 | * as it is empty. | |
1339 | */ | |
1340 | if (cfqq->p_root) { | |
1341 | rb_erase(&cfqq->p_node, cfqq->p_root); | |
1342 | cfqq->p_root = NULL; | |
1343 | } | |
1344 | } | |
1da177e4 LT |
1345 | } |
1346 | ||
5e705374 | 1347 | static void cfq_add_rq_rb(struct request *rq) |
1da177e4 | 1348 | { |
5e705374 | 1349 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
1da177e4 | 1350 | struct cfq_data *cfqd = cfqq->cfqd; |
a36e71f9 | 1351 | struct request *__alias, *prev; |
1da177e4 | 1352 | |
5380a101 | 1353 | cfqq->queued[rq_is_sync(rq)]++; |
1da177e4 LT |
1354 | |
1355 | /* | |
1356 | * looks a little odd, but the first insert might return an alias. | |
1357 | * if that happens, put the alias on the dispatch list | |
1358 | */ | |
21183b07 | 1359 | while ((__alias = elv_rb_add(&cfqq->sort_list, rq)) != NULL) |
5e705374 | 1360 | cfq_dispatch_insert(cfqd->queue, __alias); |
5fccbf61 JA |
1361 | |
1362 | if (!cfq_cfqq_on_rr(cfqq)) | |
1363 | cfq_add_cfqq_rr(cfqd, cfqq); | |
5044eed4 JA |
1364 | |
1365 | /* | |
1366 | * check if this request is a better next-serve candidate | |
1367 | */ | |
a36e71f9 | 1368 | prev = cfqq->next_rq; |
cf7c25cf | 1369 | cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq, cfqd->last_position); |
a36e71f9 JA |
1370 | |
1371 | /* | |
1372 | * adjust priority tree position, if ->next_rq changes | |
1373 | */ | |
1374 | if (prev != cfqq->next_rq) | |
1375 | cfq_prio_tree_add(cfqd, cfqq); | |
1376 | ||
5044eed4 | 1377 | BUG_ON(!cfqq->next_rq); |
1da177e4 LT |
1378 | } |
1379 | ||
febffd61 | 1380 | static void cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq) |
1da177e4 | 1381 | { |
5380a101 JA |
1382 | elv_rb_del(&cfqq->sort_list, rq); |
1383 | cfqq->queued[rq_is_sync(rq)]--; | |
cdc1184c DS |
1384 | blkiocg_update_request_remove_stats(&cfqq->cfqg->blkg, rq_data_dir(rq), |
1385 | rq_is_sync(rq)); | |
5e705374 | 1386 | cfq_add_rq_rb(rq); |
cdc1184c DS |
1387 | blkiocg_update_request_add_stats( |
1388 | &cfqq->cfqg->blkg, &cfqq->cfqd->serving_group->blkg, | |
1389 | rq_data_dir(rq), rq_is_sync(rq)); | |
1da177e4 LT |
1390 | } |
1391 | ||
206dc69b JA |
1392 | static struct request * |
1393 | cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio) | |
1da177e4 | 1394 | { |
206dc69b | 1395 | struct task_struct *tsk = current; |
91fac317 | 1396 | struct cfq_io_context *cic; |
206dc69b | 1397 | struct cfq_queue *cfqq; |
1da177e4 | 1398 | |
4ac845a2 | 1399 | cic = cfq_cic_lookup(cfqd, tsk->io_context); |
91fac317 VT |
1400 | if (!cic) |
1401 | return NULL; | |
1402 | ||
1403 | cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); | |
89850f7e JA |
1404 | if (cfqq) { |
1405 | sector_t sector = bio->bi_sector + bio_sectors(bio); | |
1406 | ||
21183b07 | 1407 | return elv_rb_find(&cfqq->sort_list, sector); |
89850f7e | 1408 | } |
1da177e4 | 1409 | |
1da177e4 LT |
1410 | return NULL; |
1411 | } | |
1412 | ||
165125e1 | 1413 | static void cfq_activate_request(struct request_queue *q, struct request *rq) |
1da177e4 | 1414 | { |
22e2c507 | 1415 | struct cfq_data *cfqd = q->elevator->elevator_data; |
3b18152c | 1416 | |
53c583d2 | 1417 | cfqd->rq_in_driver++; |
7b679138 | 1418 | cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "activate rq, drv=%d", |
53c583d2 | 1419 | cfqd->rq_in_driver); |
25776e35 | 1420 | |
5b93629b | 1421 | cfqd->last_position = blk_rq_pos(rq) + blk_rq_sectors(rq); |
1da177e4 LT |
1422 | } |
1423 | ||
165125e1 | 1424 | static void cfq_deactivate_request(struct request_queue *q, struct request *rq) |
1da177e4 | 1425 | { |
b4878f24 JA |
1426 | struct cfq_data *cfqd = q->elevator->elevator_data; |
1427 | ||
53c583d2 CZ |
1428 | WARN_ON(!cfqd->rq_in_driver); |
1429 | cfqd->rq_in_driver--; | |
7b679138 | 1430 | cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "deactivate rq, drv=%d", |
53c583d2 | 1431 | cfqd->rq_in_driver); |
1da177e4 LT |
1432 | } |
1433 | ||
b4878f24 | 1434 | static void cfq_remove_request(struct request *rq) |
1da177e4 | 1435 | { |
5e705374 | 1436 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
21183b07 | 1437 | |
5e705374 JA |
1438 | if (cfqq->next_rq == rq) |
1439 | cfqq->next_rq = cfq_find_next_rq(cfqq->cfqd, cfqq, rq); | |
1da177e4 | 1440 | |
b4878f24 | 1441 | list_del_init(&rq->queuelist); |
5e705374 | 1442 | cfq_del_rq_rb(rq); |
374f84ac | 1443 | |
45333d5a | 1444 | cfqq->cfqd->rq_queued--; |
cdc1184c DS |
1445 | blkiocg_update_request_remove_stats(&cfqq->cfqg->blkg, rq_data_dir(rq), |
1446 | rq_is_sync(rq)); | |
374f84ac JA |
1447 | if (rq_is_meta(rq)) { |
1448 | WARN_ON(!cfqq->meta_pending); | |
1449 | cfqq->meta_pending--; | |
1450 | } | |
1da177e4 LT |
1451 | } |
1452 | ||
165125e1 JA |
1453 | static int cfq_merge(struct request_queue *q, struct request **req, |
1454 | struct bio *bio) | |
1da177e4 LT |
1455 | { |
1456 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1457 | struct request *__rq; | |
1da177e4 | 1458 | |
206dc69b | 1459 | __rq = cfq_find_rq_fmerge(cfqd, bio); |
22e2c507 | 1460 | if (__rq && elv_rq_merge_ok(__rq, bio)) { |
9817064b JA |
1461 | *req = __rq; |
1462 | return ELEVATOR_FRONT_MERGE; | |
1da177e4 LT |
1463 | } |
1464 | ||
1465 | return ELEVATOR_NO_MERGE; | |
1da177e4 LT |
1466 | } |
1467 | ||
165125e1 | 1468 | static void cfq_merged_request(struct request_queue *q, struct request *req, |
21183b07 | 1469 | int type) |
1da177e4 | 1470 | { |
21183b07 | 1471 | if (type == ELEVATOR_FRONT_MERGE) { |
5e705374 | 1472 | struct cfq_queue *cfqq = RQ_CFQQ(req); |
1da177e4 | 1473 | |
5e705374 | 1474 | cfq_reposition_rq_rb(cfqq, req); |
1da177e4 | 1475 | } |
1da177e4 LT |
1476 | } |
1477 | ||
812d4026 DS |
1478 | static void cfq_bio_merged(struct request_queue *q, struct request *req, |
1479 | struct bio *bio) | |
1480 | { | |
1481 | struct cfq_queue *cfqq = RQ_CFQQ(req); | |
1482 | blkiocg_update_io_merged_stats(&cfqq->cfqg->blkg, bio_data_dir(bio), | |
1483 | cfq_bio_sync(bio)); | |
1484 | } | |
1485 | ||
1da177e4 | 1486 | static void |
165125e1 | 1487 | cfq_merged_requests(struct request_queue *q, struct request *rq, |
1da177e4 LT |
1488 | struct request *next) |
1489 | { | |
cf7c25cf | 1490 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 JA |
1491 | /* |
1492 | * reposition in fifo if next is older than rq | |
1493 | */ | |
1494 | if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && | |
30996f40 | 1495 | time_before(rq_fifo_time(next), rq_fifo_time(rq))) { |
22e2c507 | 1496 | list_move(&rq->queuelist, &next->queuelist); |
30996f40 JA |
1497 | rq_set_fifo_time(rq, rq_fifo_time(next)); |
1498 | } | |
22e2c507 | 1499 | |
cf7c25cf CZ |
1500 | if (cfqq->next_rq == next) |
1501 | cfqq->next_rq = rq; | |
b4878f24 | 1502 | cfq_remove_request(next); |
812d4026 DS |
1503 | blkiocg_update_io_merged_stats(&cfqq->cfqg->blkg, rq_data_dir(next), |
1504 | rq_is_sync(next)); | |
22e2c507 JA |
1505 | } |
1506 | ||
165125e1 | 1507 | static int cfq_allow_merge(struct request_queue *q, struct request *rq, |
da775265 JA |
1508 | struct bio *bio) |
1509 | { | |
1510 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
91fac317 | 1511 | struct cfq_io_context *cic; |
da775265 | 1512 | struct cfq_queue *cfqq; |
da775265 JA |
1513 | |
1514 | /* | |
ec8acb69 | 1515 | * Disallow merge of a sync bio into an async request. |
da775265 | 1516 | */ |
91fac317 | 1517 | if (cfq_bio_sync(bio) && !rq_is_sync(rq)) |
a6151c3a | 1518 | return false; |
da775265 JA |
1519 | |
1520 | /* | |
719d3402 JA |
1521 | * Lookup the cfqq that this bio will be queued with. Allow |
1522 | * merge only if rq is queued there. | |
da775265 | 1523 | */ |
4ac845a2 | 1524 | cic = cfq_cic_lookup(cfqd, current->io_context); |
91fac317 | 1525 | if (!cic) |
a6151c3a | 1526 | return false; |
719d3402 | 1527 | |
91fac317 | 1528 | cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); |
a6151c3a | 1529 | return cfqq == RQ_CFQQ(rq); |
da775265 JA |
1530 | } |
1531 | ||
812df48d DS |
1532 | static inline void cfq_del_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1533 | { | |
1534 | del_timer(&cfqd->idle_slice_timer); | |
1535 | blkiocg_update_idle_time_stats(&cfqq->cfqg->blkg); | |
1536 | } | |
1537 | ||
febffd61 JA |
1538 | static void __cfq_set_active_queue(struct cfq_data *cfqd, |
1539 | struct cfq_queue *cfqq) | |
22e2c507 JA |
1540 | { |
1541 | if (cfqq) { | |
b1ffe737 DS |
1542 | cfq_log_cfqq(cfqd, cfqq, "set_active wl_prio:%d wl_type:%d", |
1543 | cfqd->serving_prio, cfqd->serving_type); | |
cdc1184c | 1544 | blkiocg_update_set_active_queue_stats(&cfqq->cfqg->blkg); |
dae739eb VG |
1545 | cfqq->slice_start = 0; |
1546 | cfqq->dispatch_start = jiffies; | |
f75edf2d | 1547 | cfqq->allocated_slice = 0; |
22e2c507 | 1548 | cfqq->slice_end = 0; |
2f5cb738 JA |
1549 | cfqq->slice_dispatch = 0; |
1550 | ||
2f5cb738 | 1551 | cfq_clear_cfqq_wait_request(cfqq); |
b029195d | 1552 | cfq_clear_cfqq_must_dispatch(cfqq); |
3b18152c JA |
1553 | cfq_clear_cfqq_must_alloc_slice(cfqq); |
1554 | cfq_clear_cfqq_fifo_expire(cfqq); | |
44f7c160 | 1555 | cfq_mark_cfqq_slice_new(cfqq); |
2f5cb738 | 1556 | |
812df48d | 1557 | cfq_del_timer(cfqd, cfqq); |
22e2c507 JA |
1558 | } |
1559 | ||
1560 | cfqd->active_queue = cfqq; | |
1561 | } | |
1562 | ||
7b14e3b5 JA |
1563 | /* |
1564 | * current cfqq expired its slice (or was too idle), select new one | |
1565 | */ | |
1566 | static void | |
1567 | __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
812df48d | 1568 | bool timed_out, bool forced) |
7b14e3b5 | 1569 | { |
7b679138 JA |
1570 | cfq_log_cfqq(cfqd, cfqq, "slice expired t=%d", timed_out); |
1571 | ||
7b14e3b5 | 1572 | if (cfq_cfqq_wait_request(cfqq)) |
812df48d | 1573 | cfq_del_timer(cfqd, cfqq); |
7b14e3b5 | 1574 | |
7b14e3b5 | 1575 | cfq_clear_cfqq_wait_request(cfqq); |
f75edf2d | 1576 | cfq_clear_cfqq_wait_busy(cfqq); |
7b14e3b5 | 1577 | |
ae54abed SL |
1578 | /* |
1579 | * If this cfqq is shared between multiple processes, check to | |
1580 | * make sure that those processes are still issuing I/Os within | |
1581 | * the mean seek distance. If not, it may be time to break the | |
1582 | * queues apart again. | |
1583 | */ | |
1584 | if (cfq_cfqq_coop(cfqq) && CFQQ_SEEKY(cfqq)) | |
1585 | cfq_mark_cfqq_split_coop(cfqq); | |
1586 | ||
7b14e3b5 | 1587 | /* |
6084cdda | 1588 | * store what was left of this slice, if the queue idled/timed out |
7b14e3b5 | 1589 | */ |
7b679138 | 1590 | if (timed_out && !cfq_cfqq_slice_new(cfqq)) { |
c5b680f3 | 1591 | cfqq->slice_resid = cfqq->slice_end - jiffies; |
7b679138 JA |
1592 | cfq_log_cfqq(cfqd, cfqq, "resid=%ld", cfqq->slice_resid); |
1593 | } | |
7b14e3b5 | 1594 | |
812df48d | 1595 | cfq_group_served(cfqd, cfqq->cfqg, cfqq, forced); |
dae739eb | 1596 | |
f04a6424 VG |
1597 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) |
1598 | cfq_del_cfqq_rr(cfqd, cfqq); | |
1599 | ||
edd75ffd | 1600 | cfq_resort_rr_list(cfqd, cfqq); |
7b14e3b5 JA |
1601 | |
1602 | if (cfqq == cfqd->active_queue) | |
1603 | cfqd->active_queue = NULL; | |
1604 | ||
dae739eb VG |
1605 | if (&cfqq->cfqg->rb_node == cfqd->grp_service_tree.active) |
1606 | cfqd->grp_service_tree.active = NULL; | |
1607 | ||
7b14e3b5 JA |
1608 | if (cfqd->active_cic) { |
1609 | put_io_context(cfqd->active_cic->ioc); | |
1610 | cfqd->active_cic = NULL; | |
1611 | } | |
7b14e3b5 JA |
1612 | } |
1613 | ||
812df48d DS |
1614 | static inline void cfq_slice_expired(struct cfq_data *cfqd, bool timed_out, |
1615 | bool forced) | |
7b14e3b5 JA |
1616 | { |
1617 | struct cfq_queue *cfqq = cfqd->active_queue; | |
1618 | ||
1619 | if (cfqq) | |
812df48d | 1620 | __cfq_slice_expired(cfqd, cfqq, timed_out, forced); |
7b14e3b5 JA |
1621 | } |
1622 | ||
498d3aa2 JA |
1623 | /* |
1624 | * Get next queue for service. Unless we have a queue preemption, | |
1625 | * we'll simply select the first cfqq in the service tree. | |
1626 | */ | |
6d048f53 | 1627 | static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd) |
22e2c507 | 1628 | { |
c0324a02 | 1629 | struct cfq_rb_root *service_tree = |
cdb16e8f | 1630 | service_tree_for(cfqd->serving_group, cfqd->serving_prio, |
65b32a57 | 1631 | cfqd->serving_type); |
d9e7620e | 1632 | |
f04a6424 VG |
1633 | if (!cfqd->rq_queued) |
1634 | return NULL; | |
1635 | ||
1fa8f6d6 VG |
1636 | /* There is nothing to dispatch */ |
1637 | if (!service_tree) | |
1638 | return NULL; | |
c0324a02 CZ |
1639 | if (RB_EMPTY_ROOT(&service_tree->rb)) |
1640 | return NULL; | |
1641 | return cfq_rb_first(service_tree); | |
6d048f53 JA |
1642 | } |
1643 | ||
f04a6424 VG |
1644 | static struct cfq_queue *cfq_get_next_queue_forced(struct cfq_data *cfqd) |
1645 | { | |
25fb5169 | 1646 | struct cfq_group *cfqg; |
f04a6424 VG |
1647 | struct cfq_queue *cfqq; |
1648 | int i, j; | |
1649 | struct cfq_rb_root *st; | |
1650 | ||
1651 | if (!cfqd->rq_queued) | |
1652 | return NULL; | |
1653 | ||
25fb5169 VG |
1654 | cfqg = cfq_get_next_cfqg(cfqd); |
1655 | if (!cfqg) | |
1656 | return NULL; | |
1657 | ||
f04a6424 VG |
1658 | for_each_cfqg_st(cfqg, i, j, st) |
1659 | if ((cfqq = cfq_rb_first(st)) != NULL) | |
1660 | return cfqq; | |
1661 | return NULL; | |
1662 | } | |
1663 | ||
498d3aa2 JA |
1664 | /* |
1665 | * Get and set a new active queue for service. | |
1666 | */ | |
a36e71f9 JA |
1667 | static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd, |
1668 | struct cfq_queue *cfqq) | |
6d048f53 | 1669 | { |
e00ef799 | 1670 | if (!cfqq) |
a36e71f9 | 1671 | cfqq = cfq_get_next_queue(cfqd); |
6d048f53 | 1672 | |
22e2c507 | 1673 | __cfq_set_active_queue(cfqd, cfqq); |
3b18152c | 1674 | return cfqq; |
22e2c507 JA |
1675 | } |
1676 | ||
d9e7620e JA |
1677 | static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd, |
1678 | struct request *rq) | |
1679 | { | |
83096ebf TH |
1680 | if (blk_rq_pos(rq) >= cfqd->last_position) |
1681 | return blk_rq_pos(rq) - cfqd->last_position; | |
d9e7620e | 1682 | else |
83096ebf | 1683 | return cfqd->last_position - blk_rq_pos(rq); |
d9e7620e JA |
1684 | } |
1685 | ||
b2c18e1e | 1686 | static inline int cfq_rq_close(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
e9ce335d | 1687 | struct request *rq) |
6d048f53 | 1688 | { |
e9ce335d | 1689 | return cfq_dist_from_last(cfqd, rq) <= CFQQ_CLOSE_THR; |
6d048f53 JA |
1690 | } |
1691 | ||
a36e71f9 JA |
1692 | static struct cfq_queue *cfqq_close(struct cfq_data *cfqd, |
1693 | struct cfq_queue *cur_cfqq) | |
1694 | { | |
f2d1f0ae | 1695 | struct rb_root *root = &cfqd->prio_trees[cur_cfqq->org_ioprio]; |
a36e71f9 JA |
1696 | struct rb_node *parent, *node; |
1697 | struct cfq_queue *__cfqq; | |
1698 | sector_t sector = cfqd->last_position; | |
1699 | ||
1700 | if (RB_EMPTY_ROOT(root)) | |
1701 | return NULL; | |
1702 | ||
1703 | /* | |
1704 | * First, if we find a request starting at the end of the last | |
1705 | * request, choose it. | |
1706 | */ | |
f2d1f0ae | 1707 | __cfqq = cfq_prio_tree_lookup(cfqd, root, sector, &parent, NULL); |
a36e71f9 JA |
1708 | if (__cfqq) |
1709 | return __cfqq; | |
1710 | ||
1711 | /* | |
1712 | * If the exact sector wasn't found, the parent of the NULL leaf | |
1713 | * will contain the closest sector. | |
1714 | */ | |
1715 | __cfqq = rb_entry(parent, struct cfq_queue, p_node); | |
e9ce335d | 1716 | if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq)) |
a36e71f9 JA |
1717 | return __cfqq; |
1718 | ||
2e46e8b2 | 1719 | if (blk_rq_pos(__cfqq->next_rq) < sector) |
a36e71f9 JA |
1720 | node = rb_next(&__cfqq->p_node); |
1721 | else | |
1722 | node = rb_prev(&__cfqq->p_node); | |
1723 | if (!node) | |
1724 | return NULL; | |
1725 | ||
1726 | __cfqq = rb_entry(node, struct cfq_queue, p_node); | |
e9ce335d | 1727 | if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq)) |
a36e71f9 JA |
1728 | return __cfqq; |
1729 | ||
1730 | return NULL; | |
1731 | } | |
1732 | ||
1733 | /* | |
1734 | * cfqd - obvious | |
1735 | * cur_cfqq - passed in so that we don't decide that the current queue is | |
1736 | * closely cooperating with itself. | |
1737 | * | |
1738 | * So, basically we're assuming that that cur_cfqq has dispatched at least | |
1739 | * one request, and that cfqd->last_position reflects a position on the disk | |
1740 | * associated with the I/O issued by cur_cfqq. I'm not sure this is a valid | |
1741 | * assumption. | |
1742 | */ | |
1743 | static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd, | |
b3b6d040 | 1744 | struct cfq_queue *cur_cfqq) |
6d048f53 | 1745 | { |
a36e71f9 JA |
1746 | struct cfq_queue *cfqq; |
1747 | ||
39c01b21 DS |
1748 | if (cfq_class_idle(cur_cfqq)) |
1749 | return NULL; | |
e6c5bc73 JM |
1750 | if (!cfq_cfqq_sync(cur_cfqq)) |
1751 | return NULL; | |
1752 | if (CFQQ_SEEKY(cur_cfqq)) | |
1753 | return NULL; | |
1754 | ||
b9d8f4c7 GJ |
1755 | /* |
1756 | * Don't search priority tree if it's the only queue in the group. | |
1757 | */ | |
1758 | if (cur_cfqq->cfqg->nr_cfqq == 1) | |
1759 | return NULL; | |
1760 | ||
6d048f53 | 1761 | /* |
d9e7620e JA |
1762 | * We should notice if some of the queues are cooperating, eg |
1763 | * working closely on the same area of the disk. In that case, | |
1764 | * we can group them together and don't waste time idling. | |
6d048f53 | 1765 | */ |
a36e71f9 JA |
1766 | cfqq = cfqq_close(cfqd, cur_cfqq); |
1767 | if (!cfqq) | |
1768 | return NULL; | |
1769 | ||
8682e1f1 VG |
1770 | /* If new queue belongs to different cfq_group, don't choose it */ |
1771 | if (cur_cfqq->cfqg != cfqq->cfqg) | |
1772 | return NULL; | |
1773 | ||
df5fe3e8 JM |
1774 | /* |
1775 | * It only makes sense to merge sync queues. | |
1776 | */ | |
1777 | if (!cfq_cfqq_sync(cfqq)) | |
1778 | return NULL; | |
e6c5bc73 JM |
1779 | if (CFQQ_SEEKY(cfqq)) |
1780 | return NULL; | |
df5fe3e8 | 1781 | |
c0324a02 CZ |
1782 | /* |
1783 | * Do not merge queues of different priority classes | |
1784 | */ | |
1785 | if (cfq_class_rt(cfqq) != cfq_class_rt(cur_cfqq)) | |
1786 | return NULL; | |
1787 | ||
a36e71f9 | 1788 | return cfqq; |
6d048f53 JA |
1789 | } |
1790 | ||
a6d44e98 CZ |
1791 | /* |
1792 | * Determine whether we should enforce idle window for this queue. | |
1793 | */ | |
1794 | ||
1795 | static bool cfq_should_idle(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1796 | { | |
1797 | enum wl_prio_t prio = cfqq_prio(cfqq); | |
718eee05 | 1798 | struct cfq_rb_root *service_tree = cfqq->service_tree; |
a6d44e98 | 1799 | |
f04a6424 VG |
1800 | BUG_ON(!service_tree); |
1801 | BUG_ON(!service_tree->count); | |
1802 | ||
a6d44e98 CZ |
1803 | /* We never do for idle class queues. */ |
1804 | if (prio == IDLE_WORKLOAD) | |
1805 | return false; | |
1806 | ||
1807 | /* We do for queues that were marked with idle window flag. */ | |
3c764b7a SL |
1808 | if (cfq_cfqq_idle_window(cfqq) && |
1809 | !(blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag)) | |
a6d44e98 CZ |
1810 | return true; |
1811 | ||
1812 | /* | |
1813 | * Otherwise, we do only if they are the last ones | |
1814 | * in their service tree. | |
1815 | */ | |
b1ffe737 DS |
1816 | if (service_tree->count == 1 && cfq_cfqq_sync(cfqq)) |
1817 | return 1; | |
1818 | cfq_log_cfqq(cfqd, cfqq, "Not idling. st->count:%d", | |
1819 | service_tree->count); | |
1820 | return 0; | |
a6d44e98 CZ |
1821 | } |
1822 | ||
6d048f53 | 1823 | static void cfq_arm_slice_timer(struct cfq_data *cfqd) |
22e2c507 | 1824 | { |
1792669c | 1825 | struct cfq_queue *cfqq = cfqd->active_queue; |
206dc69b | 1826 | struct cfq_io_context *cic; |
7b14e3b5 JA |
1827 | unsigned long sl; |
1828 | ||
a68bbddb | 1829 | /* |
f7d7b7a7 JA |
1830 | * SSD device without seek penalty, disable idling. But only do so |
1831 | * for devices that support queuing, otherwise we still have a problem | |
1832 | * with sync vs async workloads. | |
a68bbddb | 1833 | */ |
f7d7b7a7 | 1834 | if (blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag) |
a68bbddb JA |
1835 | return; |
1836 | ||
dd67d051 | 1837 | WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list)); |
6d048f53 | 1838 | WARN_ON(cfq_cfqq_slice_new(cfqq)); |
22e2c507 JA |
1839 | |
1840 | /* | |
1841 | * idle is disabled, either manually or by past process history | |
1842 | */ | |
a6d44e98 | 1843 | if (!cfqd->cfq_slice_idle || !cfq_should_idle(cfqd, cfqq)) |
6d048f53 JA |
1844 | return; |
1845 | ||
7b679138 | 1846 | /* |
8e550632 | 1847 | * still active requests from this queue, don't idle |
7b679138 | 1848 | */ |
8e550632 | 1849 | if (cfqq->dispatched) |
7b679138 JA |
1850 | return; |
1851 | ||
22e2c507 JA |
1852 | /* |
1853 | * task has exited, don't wait | |
1854 | */ | |
206dc69b | 1855 | cic = cfqd->active_cic; |
66dac98e | 1856 | if (!cic || !atomic_read(&cic->ioc->nr_tasks)) |
6d048f53 JA |
1857 | return; |
1858 | ||
355b659c CZ |
1859 | /* |
1860 | * If our average think time is larger than the remaining time | |
1861 | * slice, then don't idle. This avoids overrunning the allotted | |
1862 | * time slice. | |
1863 | */ | |
1864 | if (sample_valid(cic->ttime_samples) && | |
b1ffe737 DS |
1865 | (cfqq->slice_end - jiffies < cic->ttime_mean)) { |
1866 | cfq_log_cfqq(cfqd, cfqq, "Not idling. think_time:%d", | |
1867 | cic->ttime_mean); | |
355b659c | 1868 | return; |
b1ffe737 | 1869 | } |
355b659c | 1870 | |
3b18152c | 1871 | cfq_mark_cfqq_wait_request(cfqq); |
22e2c507 | 1872 | |
6d048f53 | 1873 | sl = cfqd->cfq_slice_idle; |
206dc69b | 1874 | |
7b14e3b5 | 1875 | mod_timer(&cfqd->idle_slice_timer, jiffies + sl); |
812df48d | 1876 | blkiocg_update_set_idle_time_stats(&cfqq->cfqg->blkg); |
9481ffdc | 1877 | cfq_log_cfqq(cfqd, cfqq, "arm_idle: %lu", sl); |
1da177e4 LT |
1878 | } |
1879 | ||
498d3aa2 JA |
1880 | /* |
1881 | * Move request from internal lists to the request queue dispatch list. | |
1882 | */ | |
165125e1 | 1883 | static void cfq_dispatch_insert(struct request_queue *q, struct request *rq) |
1da177e4 | 1884 | { |
3ed9a296 | 1885 | struct cfq_data *cfqd = q->elevator->elevator_data; |
5e705374 | 1886 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 | 1887 | |
7b679138 JA |
1888 | cfq_log_cfqq(cfqd, cfqq, "dispatch_insert"); |
1889 | ||
06d21886 | 1890 | cfqq->next_rq = cfq_find_next_rq(cfqd, cfqq, rq); |
5380a101 | 1891 | cfq_remove_request(rq); |
6d048f53 | 1892 | cfqq->dispatched++; |
5380a101 | 1893 | elv_dispatch_sort(q, rq); |
3ed9a296 | 1894 | |
53c583d2 | 1895 | cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]++; |
84c124da DS |
1896 | blkiocg_update_dispatch_stats(&cfqq->cfqg->blkg, blk_rq_bytes(rq), |
1897 | rq_data_dir(rq), rq_is_sync(rq)); | |
1da177e4 LT |
1898 | } |
1899 | ||
1900 | /* | |
1901 | * return expired entry, or NULL to just start from scratch in rbtree | |
1902 | */ | |
febffd61 | 1903 | static struct request *cfq_check_fifo(struct cfq_queue *cfqq) |
1da177e4 | 1904 | { |
30996f40 | 1905 | struct request *rq = NULL; |
1da177e4 | 1906 | |
3b18152c | 1907 | if (cfq_cfqq_fifo_expire(cfqq)) |
1da177e4 | 1908 | return NULL; |
cb887411 JA |
1909 | |
1910 | cfq_mark_cfqq_fifo_expire(cfqq); | |
1911 | ||
89850f7e JA |
1912 | if (list_empty(&cfqq->fifo)) |
1913 | return NULL; | |
1da177e4 | 1914 | |
89850f7e | 1915 | rq = rq_entry_fifo(cfqq->fifo.next); |
30996f40 | 1916 | if (time_before(jiffies, rq_fifo_time(rq))) |
7b679138 | 1917 | rq = NULL; |
1da177e4 | 1918 | |
30996f40 | 1919 | cfq_log_cfqq(cfqq->cfqd, cfqq, "fifo=%p", rq); |
6d048f53 | 1920 | return rq; |
1da177e4 LT |
1921 | } |
1922 | ||
22e2c507 JA |
1923 | static inline int |
1924 | cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1925 | { | |
1926 | const int base_rq = cfqd->cfq_slice_async_rq; | |
1da177e4 | 1927 | |
22e2c507 | 1928 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); |
1da177e4 | 1929 | |
22e2c507 | 1930 | return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio)); |
1da177e4 LT |
1931 | } |
1932 | ||
df5fe3e8 JM |
1933 | /* |
1934 | * Must be called with the queue_lock held. | |
1935 | */ | |
1936 | static int cfqq_process_refs(struct cfq_queue *cfqq) | |
1937 | { | |
1938 | int process_refs, io_refs; | |
1939 | ||
1940 | io_refs = cfqq->allocated[READ] + cfqq->allocated[WRITE]; | |
1941 | process_refs = atomic_read(&cfqq->ref) - io_refs; | |
1942 | BUG_ON(process_refs < 0); | |
1943 | return process_refs; | |
1944 | } | |
1945 | ||
1946 | static void cfq_setup_merge(struct cfq_queue *cfqq, struct cfq_queue *new_cfqq) | |
1947 | { | |
e6c5bc73 | 1948 | int process_refs, new_process_refs; |
df5fe3e8 JM |
1949 | struct cfq_queue *__cfqq; |
1950 | ||
1951 | /* Avoid a circular list and skip interim queue merges */ | |
1952 | while ((__cfqq = new_cfqq->new_cfqq)) { | |
1953 | if (__cfqq == cfqq) | |
1954 | return; | |
1955 | new_cfqq = __cfqq; | |
1956 | } | |
1957 | ||
1958 | process_refs = cfqq_process_refs(cfqq); | |
1959 | /* | |
1960 | * If the process for the cfqq has gone away, there is no | |
1961 | * sense in merging the queues. | |
1962 | */ | |
1963 | if (process_refs == 0) | |
1964 | return; | |
1965 | ||
e6c5bc73 JM |
1966 | /* |
1967 | * Merge in the direction of the lesser amount of work. | |
1968 | */ | |
1969 | new_process_refs = cfqq_process_refs(new_cfqq); | |
1970 | if (new_process_refs >= process_refs) { | |
1971 | cfqq->new_cfqq = new_cfqq; | |
1972 | atomic_add(process_refs, &new_cfqq->ref); | |
1973 | } else { | |
1974 | new_cfqq->new_cfqq = cfqq; | |
1975 | atomic_add(new_process_refs, &cfqq->ref); | |
1976 | } | |
df5fe3e8 JM |
1977 | } |
1978 | ||
cdb16e8f | 1979 | static enum wl_type_t cfq_choose_wl(struct cfq_data *cfqd, |
65b32a57 | 1980 | struct cfq_group *cfqg, enum wl_prio_t prio) |
718eee05 CZ |
1981 | { |
1982 | struct cfq_queue *queue; | |
1983 | int i; | |
1984 | bool key_valid = false; | |
1985 | unsigned long lowest_key = 0; | |
1986 | enum wl_type_t cur_best = SYNC_NOIDLE_WORKLOAD; | |
1987 | ||
65b32a57 VG |
1988 | for (i = 0; i <= SYNC_WORKLOAD; ++i) { |
1989 | /* select the one with lowest rb_key */ | |
1990 | queue = cfq_rb_first(service_tree_for(cfqg, prio, i)); | |
718eee05 CZ |
1991 | if (queue && |
1992 | (!key_valid || time_before(queue->rb_key, lowest_key))) { | |
1993 | lowest_key = queue->rb_key; | |
1994 | cur_best = i; | |
1995 | key_valid = true; | |
1996 | } | |
1997 | } | |
1998 | ||
1999 | return cur_best; | |
2000 | } | |
2001 | ||
cdb16e8f | 2002 | static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg) |
718eee05 | 2003 | { |
718eee05 CZ |
2004 | unsigned slice; |
2005 | unsigned count; | |
cdb16e8f | 2006 | struct cfq_rb_root *st; |
58ff82f3 | 2007 | unsigned group_slice; |
718eee05 | 2008 | |
1fa8f6d6 VG |
2009 | if (!cfqg) { |
2010 | cfqd->serving_prio = IDLE_WORKLOAD; | |
2011 | cfqd->workload_expires = jiffies + 1; | |
2012 | return; | |
2013 | } | |
2014 | ||
718eee05 | 2015 | /* Choose next priority. RT > BE > IDLE */ |
58ff82f3 | 2016 | if (cfq_group_busy_queues_wl(RT_WORKLOAD, cfqd, cfqg)) |
718eee05 | 2017 | cfqd->serving_prio = RT_WORKLOAD; |
58ff82f3 | 2018 | else if (cfq_group_busy_queues_wl(BE_WORKLOAD, cfqd, cfqg)) |
718eee05 CZ |
2019 | cfqd->serving_prio = BE_WORKLOAD; |
2020 | else { | |
2021 | cfqd->serving_prio = IDLE_WORKLOAD; | |
2022 | cfqd->workload_expires = jiffies + 1; | |
2023 | return; | |
2024 | } | |
2025 | ||
2026 | /* | |
2027 | * For RT and BE, we have to choose also the type | |
2028 | * (SYNC, SYNC_NOIDLE, ASYNC), and to compute a workload | |
2029 | * expiration time | |
2030 | */ | |
65b32a57 | 2031 | st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type); |
cdb16e8f | 2032 | count = st->count; |
718eee05 CZ |
2033 | |
2034 | /* | |
65b32a57 | 2035 | * check workload expiration, and that we still have other queues ready |
718eee05 | 2036 | */ |
65b32a57 | 2037 | if (count && !time_after(jiffies, cfqd->workload_expires)) |
718eee05 CZ |
2038 | return; |
2039 | ||
2040 | /* otherwise select new workload type */ | |
2041 | cfqd->serving_type = | |
65b32a57 VG |
2042 | cfq_choose_wl(cfqd, cfqg, cfqd->serving_prio); |
2043 | st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type); | |
cdb16e8f | 2044 | count = st->count; |
718eee05 CZ |
2045 | |
2046 | /* | |
2047 | * the workload slice is computed as a fraction of target latency | |
2048 | * proportional to the number of queues in that workload, over | |
2049 | * all the queues in the same priority class | |
2050 | */ | |
58ff82f3 VG |
2051 | group_slice = cfq_group_slice(cfqd, cfqg); |
2052 | ||
2053 | slice = group_slice * count / | |
2054 | max_t(unsigned, cfqg->busy_queues_avg[cfqd->serving_prio], | |
2055 | cfq_group_busy_queues_wl(cfqd->serving_prio, cfqd, cfqg)); | |
718eee05 | 2056 | |
f26bd1f0 VG |
2057 | if (cfqd->serving_type == ASYNC_WORKLOAD) { |
2058 | unsigned int tmp; | |
2059 | ||
2060 | /* | |
2061 | * Async queues are currently system wide. Just taking | |
2062 | * proportion of queues with-in same group will lead to higher | |
2063 | * async ratio system wide as generally root group is going | |
2064 | * to have higher weight. A more accurate thing would be to | |
2065 | * calculate system wide asnc/sync ratio. | |
2066 | */ | |
2067 | tmp = cfq_target_latency * cfqg_busy_async_queues(cfqd, cfqg); | |
2068 | tmp = tmp/cfqd->busy_queues; | |
2069 | slice = min_t(unsigned, slice, tmp); | |
2070 | ||
718eee05 CZ |
2071 | /* async workload slice is scaled down according to |
2072 | * the sync/async slice ratio. */ | |
2073 | slice = slice * cfqd->cfq_slice[0] / cfqd->cfq_slice[1]; | |
f26bd1f0 | 2074 | } else |
718eee05 CZ |
2075 | /* sync workload slice is at least 2 * cfq_slice_idle */ |
2076 | slice = max(slice, 2 * cfqd->cfq_slice_idle); | |
2077 | ||
2078 | slice = max_t(unsigned, slice, CFQ_MIN_TT); | |
b1ffe737 | 2079 | cfq_log(cfqd, "workload slice:%d", slice); |
718eee05 | 2080 | cfqd->workload_expires = jiffies + slice; |
8e550632 | 2081 | cfqd->noidle_tree_requires_idle = false; |
718eee05 CZ |
2082 | } |
2083 | ||
1fa8f6d6 VG |
2084 | static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd) |
2085 | { | |
2086 | struct cfq_rb_root *st = &cfqd->grp_service_tree; | |
25bc6b07 | 2087 | struct cfq_group *cfqg; |
1fa8f6d6 VG |
2088 | |
2089 | if (RB_EMPTY_ROOT(&st->rb)) | |
2090 | return NULL; | |
25bc6b07 VG |
2091 | cfqg = cfq_rb_first_group(st); |
2092 | st->active = &cfqg->rb_node; | |
2093 | update_min_vdisktime(st); | |
2094 | return cfqg; | |
1fa8f6d6 VG |
2095 | } |
2096 | ||
cdb16e8f VG |
2097 | static void cfq_choose_cfqg(struct cfq_data *cfqd) |
2098 | { | |
1fa8f6d6 VG |
2099 | struct cfq_group *cfqg = cfq_get_next_cfqg(cfqd); |
2100 | ||
2101 | cfqd->serving_group = cfqg; | |
dae739eb VG |
2102 | |
2103 | /* Restore the workload type data */ | |
2104 | if (cfqg->saved_workload_slice) { | |
2105 | cfqd->workload_expires = jiffies + cfqg->saved_workload_slice; | |
2106 | cfqd->serving_type = cfqg->saved_workload; | |
2107 | cfqd->serving_prio = cfqg->saved_serving_prio; | |
66ae2919 GJ |
2108 | } else |
2109 | cfqd->workload_expires = jiffies - 1; | |
2110 | ||
1fa8f6d6 | 2111 | choose_service_tree(cfqd, cfqg); |
cdb16e8f VG |
2112 | } |
2113 | ||
22e2c507 | 2114 | /* |
498d3aa2 JA |
2115 | * Select a queue for service. If we have a current active queue, |
2116 | * check whether to continue servicing it, or retrieve and set a new one. | |
22e2c507 | 2117 | */ |
1b5ed5e1 | 2118 | static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) |
1da177e4 | 2119 | { |
a36e71f9 | 2120 | struct cfq_queue *cfqq, *new_cfqq = NULL; |
1da177e4 | 2121 | |
22e2c507 JA |
2122 | cfqq = cfqd->active_queue; |
2123 | if (!cfqq) | |
2124 | goto new_queue; | |
1da177e4 | 2125 | |
f04a6424 VG |
2126 | if (!cfqd->rq_queued) |
2127 | return NULL; | |
c244bb50 VG |
2128 | |
2129 | /* | |
2130 | * We were waiting for group to get backlogged. Expire the queue | |
2131 | */ | |
2132 | if (cfq_cfqq_wait_busy(cfqq) && !RB_EMPTY_ROOT(&cfqq->sort_list)) | |
2133 | goto expire; | |
2134 | ||
22e2c507 | 2135 | /* |
6d048f53 | 2136 | * The active queue has run out of time, expire it and select new. |
22e2c507 | 2137 | */ |
7667aa06 VG |
2138 | if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq)) { |
2139 | /* | |
2140 | * If slice had not expired at the completion of last request | |
2141 | * we might not have turned on wait_busy flag. Don't expire | |
2142 | * the queue yet. Allow the group to get backlogged. | |
2143 | * | |
2144 | * The very fact that we have used the slice, that means we | |
2145 | * have been idling all along on this queue and it should be | |
2146 | * ok to wait for this request to complete. | |
2147 | */ | |
82bbbf28 VG |
2148 | if (cfqq->cfqg->nr_cfqq == 1 && RB_EMPTY_ROOT(&cfqq->sort_list) |
2149 | && cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) { | |
2150 | cfqq = NULL; | |
7667aa06 | 2151 | goto keep_queue; |
82bbbf28 | 2152 | } else |
7667aa06 VG |
2153 | goto expire; |
2154 | } | |
1da177e4 | 2155 | |
22e2c507 | 2156 | /* |
6d048f53 JA |
2157 | * The active queue has requests and isn't expired, allow it to |
2158 | * dispatch. | |
22e2c507 | 2159 | */ |
dd67d051 | 2160 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
22e2c507 | 2161 | goto keep_queue; |
6d048f53 | 2162 | |
a36e71f9 JA |
2163 | /* |
2164 | * If another queue has a request waiting within our mean seek | |
2165 | * distance, let it run. The expire code will check for close | |
2166 | * cooperators and put the close queue at the front of the service | |
df5fe3e8 | 2167 | * tree. If possible, merge the expiring queue with the new cfqq. |
a36e71f9 | 2168 | */ |
b3b6d040 | 2169 | new_cfqq = cfq_close_cooperator(cfqd, cfqq); |
df5fe3e8 JM |
2170 | if (new_cfqq) { |
2171 | if (!cfqq->new_cfqq) | |
2172 | cfq_setup_merge(cfqq, new_cfqq); | |
a36e71f9 | 2173 | goto expire; |
df5fe3e8 | 2174 | } |
a36e71f9 | 2175 | |
6d048f53 JA |
2176 | /* |
2177 | * No requests pending. If the active queue still has requests in | |
2178 | * flight or is idling for a new request, allow either of these | |
2179 | * conditions to happen (or time out) before selecting a new queue. | |
2180 | */ | |
cc197479 | 2181 | if (timer_pending(&cfqd->idle_slice_timer) || |
a6d44e98 | 2182 | (cfqq->dispatched && cfq_should_idle(cfqd, cfqq))) { |
caaa5f9f JA |
2183 | cfqq = NULL; |
2184 | goto keep_queue; | |
22e2c507 JA |
2185 | } |
2186 | ||
3b18152c | 2187 | expire: |
812df48d | 2188 | cfq_slice_expired(cfqd, 0, false); |
3b18152c | 2189 | new_queue: |
718eee05 CZ |
2190 | /* |
2191 | * Current queue expired. Check if we have to switch to a new | |
2192 | * service tree | |
2193 | */ | |
2194 | if (!new_cfqq) | |
cdb16e8f | 2195 | cfq_choose_cfqg(cfqd); |
718eee05 | 2196 | |
a36e71f9 | 2197 | cfqq = cfq_set_active_queue(cfqd, new_cfqq); |
22e2c507 | 2198 | keep_queue: |
3b18152c | 2199 | return cfqq; |
22e2c507 JA |
2200 | } |
2201 | ||
febffd61 | 2202 | static int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq) |
d9e7620e JA |
2203 | { |
2204 | int dispatched = 0; | |
2205 | ||
2206 | while (cfqq->next_rq) { | |
2207 | cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq); | |
2208 | dispatched++; | |
2209 | } | |
2210 | ||
2211 | BUG_ON(!list_empty(&cfqq->fifo)); | |
f04a6424 VG |
2212 | |
2213 | /* By default cfqq is not expired if it is empty. Do it explicitly */ | |
812df48d | 2214 | __cfq_slice_expired(cfqq->cfqd, cfqq, 0, true); |
d9e7620e JA |
2215 | return dispatched; |
2216 | } | |
2217 | ||
498d3aa2 JA |
2218 | /* |
2219 | * Drain our current requests. Used for barriers and when switching | |
2220 | * io schedulers on-the-fly. | |
2221 | */ | |
d9e7620e | 2222 | static int cfq_forced_dispatch(struct cfq_data *cfqd) |
1b5ed5e1 | 2223 | { |
0871714e | 2224 | struct cfq_queue *cfqq; |
d9e7620e | 2225 | int dispatched = 0; |
cdb16e8f | 2226 | |
f04a6424 VG |
2227 | while ((cfqq = cfq_get_next_queue_forced(cfqd)) != NULL) |
2228 | dispatched += __cfq_forced_dispatch_cfqq(cfqq); | |
1b5ed5e1 | 2229 | |
812df48d | 2230 | cfq_slice_expired(cfqd, 0, true); |
1b5ed5e1 TH |
2231 | BUG_ON(cfqd->busy_queues); |
2232 | ||
6923715a | 2233 | cfq_log(cfqd, "forced_dispatch=%d", dispatched); |
1b5ed5e1 TH |
2234 | return dispatched; |
2235 | } | |
2236 | ||
abc3c744 SL |
2237 | static inline bool cfq_slice_used_soon(struct cfq_data *cfqd, |
2238 | struct cfq_queue *cfqq) | |
2239 | { | |
2240 | /* the queue hasn't finished any request, can't estimate */ | |
2241 | if (cfq_cfqq_slice_new(cfqq)) | |
2242 | return 1; | |
2243 | if (time_after(jiffies + cfqd->cfq_slice_idle * cfqq->dispatched, | |
2244 | cfqq->slice_end)) | |
2245 | return 1; | |
2246 | ||
2247 | return 0; | |
2248 | } | |
2249 | ||
0b182d61 | 2250 | static bool cfq_may_dispatch(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
2f5cb738 | 2251 | { |
2f5cb738 | 2252 | unsigned int max_dispatch; |
22e2c507 | 2253 | |
5ad531db JA |
2254 | /* |
2255 | * Drain async requests before we start sync IO | |
2256 | */ | |
53c583d2 | 2257 | if (cfq_should_idle(cfqd, cfqq) && cfqd->rq_in_flight[BLK_RW_ASYNC]) |
0b182d61 | 2258 | return false; |
5ad531db | 2259 | |
2f5cb738 JA |
2260 | /* |
2261 | * If this is an async queue and we have sync IO in flight, let it wait | |
2262 | */ | |
53c583d2 | 2263 | if (cfqd->rq_in_flight[BLK_RW_SYNC] && !cfq_cfqq_sync(cfqq)) |
0b182d61 | 2264 | return false; |
2f5cb738 | 2265 | |
abc3c744 | 2266 | max_dispatch = max_t(unsigned int, cfqd->cfq_quantum / 2, 1); |
2f5cb738 JA |
2267 | if (cfq_class_idle(cfqq)) |
2268 | max_dispatch = 1; | |
b4878f24 | 2269 | |
2f5cb738 JA |
2270 | /* |
2271 | * Does this cfqq already have too much IO in flight? | |
2272 | */ | |
2273 | if (cfqq->dispatched >= max_dispatch) { | |
2274 | /* | |
2275 | * idle queue must always only have a single IO in flight | |
2276 | */ | |
3ed9a296 | 2277 | if (cfq_class_idle(cfqq)) |
0b182d61 | 2278 | return false; |
3ed9a296 | 2279 | |
2f5cb738 JA |
2280 | /* |
2281 | * We have other queues, don't allow more IO from this one | |
2282 | */ | |
abc3c744 | 2283 | if (cfqd->busy_queues > 1 && cfq_slice_used_soon(cfqd, cfqq)) |
0b182d61 | 2284 | return false; |
9ede209e | 2285 | |
365722bb | 2286 | /* |
474b18cc | 2287 | * Sole queue user, no limit |
365722bb | 2288 | */ |
abc3c744 SL |
2289 | if (cfqd->busy_queues == 1) |
2290 | max_dispatch = -1; | |
2291 | else | |
2292 | /* | |
2293 | * Normally we start throttling cfqq when cfq_quantum/2 | |
2294 | * requests have been dispatched. But we can drive | |
2295 | * deeper queue depths at the beginning of slice | |
2296 | * subjected to upper limit of cfq_quantum. | |
2297 | * */ | |
2298 | max_dispatch = cfqd->cfq_quantum; | |
8e296755 JA |
2299 | } |
2300 | ||
2301 | /* | |
2302 | * Async queues must wait a bit before being allowed dispatch. | |
2303 | * We also ramp up the dispatch depth gradually for async IO, | |
2304 | * based on the last sync IO we serviced | |
2305 | */ | |
963b72fc | 2306 | if (!cfq_cfqq_sync(cfqq) && cfqd->cfq_latency) { |
573412b2 | 2307 | unsigned long last_sync = jiffies - cfqd->last_delayed_sync; |
8e296755 | 2308 | unsigned int depth; |
365722bb | 2309 | |
61f0c1dc | 2310 | depth = last_sync / cfqd->cfq_slice[1]; |
e00c54c3 JA |
2311 | if (!depth && !cfqq->dispatched) |
2312 | depth = 1; | |
8e296755 JA |
2313 | if (depth < max_dispatch) |
2314 | max_dispatch = depth; | |
2f5cb738 | 2315 | } |
3ed9a296 | 2316 | |
0b182d61 JA |
2317 | /* |
2318 | * If we're below the current max, allow a dispatch | |
2319 | */ | |
2320 | return cfqq->dispatched < max_dispatch; | |
2321 | } | |
2322 | ||
2323 | /* | |
2324 | * Dispatch a request from cfqq, moving them to the request queue | |
2325 | * dispatch list. | |
2326 | */ | |
2327 | static bool cfq_dispatch_request(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
2328 | { | |
2329 | struct request *rq; | |
2330 | ||
2331 | BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list)); | |
2332 | ||
2333 | if (!cfq_may_dispatch(cfqd, cfqq)) | |
2334 | return false; | |
2335 | ||
2336 | /* | |
2337 | * follow expired path, else get first next available | |
2338 | */ | |
2339 | rq = cfq_check_fifo(cfqq); | |
2340 | if (!rq) | |
2341 | rq = cfqq->next_rq; | |
2342 | ||
2343 | /* | |
2344 | * insert request into driver dispatch list | |
2345 | */ | |
2346 | cfq_dispatch_insert(cfqd->queue, rq); | |
2347 | ||
2348 | if (!cfqd->active_cic) { | |
2349 | struct cfq_io_context *cic = RQ_CIC(rq); | |
2350 | ||
2351 | atomic_long_inc(&cic->ioc->refcount); | |
2352 | cfqd->active_cic = cic; | |
2353 | } | |
2354 | ||
2355 | return true; | |
2356 | } | |
2357 | ||
2358 | /* | |
2359 | * Find the cfqq that we need to service and move a request from that to the | |
2360 | * dispatch list | |
2361 | */ | |
2362 | static int cfq_dispatch_requests(struct request_queue *q, int force) | |
2363 | { | |
2364 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
2365 | struct cfq_queue *cfqq; | |
2366 | ||
2367 | if (!cfqd->busy_queues) | |
2368 | return 0; | |
2369 | ||
2370 | if (unlikely(force)) | |
2371 | return cfq_forced_dispatch(cfqd); | |
2372 | ||
2373 | cfqq = cfq_select_queue(cfqd); | |
2374 | if (!cfqq) | |
8e296755 JA |
2375 | return 0; |
2376 | ||
2f5cb738 | 2377 | /* |
0b182d61 | 2378 | * Dispatch a request from this cfqq, if it is allowed |
2f5cb738 | 2379 | */ |
0b182d61 JA |
2380 | if (!cfq_dispatch_request(cfqd, cfqq)) |
2381 | return 0; | |
2382 | ||
2f5cb738 | 2383 | cfqq->slice_dispatch++; |
b029195d | 2384 | cfq_clear_cfqq_must_dispatch(cfqq); |
22e2c507 | 2385 | |
2f5cb738 JA |
2386 | /* |
2387 | * expire an async queue immediately if it has used up its slice. idle | |
2388 | * queue always expire after 1 dispatch round. | |
2389 | */ | |
2390 | if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) && | |
2391 | cfqq->slice_dispatch >= cfq_prio_to_maxrq(cfqd, cfqq)) || | |
2392 | cfq_class_idle(cfqq))) { | |
2393 | cfqq->slice_end = jiffies + 1; | |
812df48d | 2394 | cfq_slice_expired(cfqd, 0, false); |
1da177e4 LT |
2395 | } |
2396 | ||
b217a903 | 2397 | cfq_log_cfqq(cfqd, cfqq, "dispatched a request"); |
812df48d DS |
2398 | /* |
2399 | * This is needed since we don't exactly match the mod_timer() and | |
2400 | * del_timer() calls in CFQ. | |
2401 | */ | |
2402 | blkiocg_update_idle_time_stats(&cfqq->cfqg->blkg); | |
2f5cb738 | 2403 | return 1; |
1da177e4 LT |
2404 | } |
2405 | ||
1da177e4 | 2406 | /* |
5e705374 JA |
2407 | * task holds one reference to the queue, dropped when task exits. each rq |
2408 | * in-flight on this queue also holds a reference, dropped when rq is freed. | |
1da177e4 | 2409 | * |
b1c35769 | 2410 | * Each cfq queue took a reference on the parent group. Drop it now. |
1da177e4 LT |
2411 | * queue lock must be held here. |
2412 | */ | |
2413 | static void cfq_put_queue(struct cfq_queue *cfqq) | |
2414 | { | |
22e2c507 | 2415 | struct cfq_data *cfqd = cfqq->cfqd; |
878eaddd | 2416 | struct cfq_group *cfqg, *orig_cfqg; |
22e2c507 JA |
2417 | |
2418 | BUG_ON(atomic_read(&cfqq->ref) <= 0); | |
1da177e4 LT |
2419 | |
2420 | if (!atomic_dec_and_test(&cfqq->ref)) | |
2421 | return; | |
2422 | ||
7b679138 | 2423 | cfq_log_cfqq(cfqd, cfqq, "put_queue"); |
1da177e4 | 2424 | BUG_ON(rb_first(&cfqq->sort_list)); |
22e2c507 | 2425 | BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]); |
b1c35769 | 2426 | cfqg = cfqq->cfqg; |
878eaddd | 2427 | orig_cfqg = cfqq->orig_cfqg; |
1da177e4 | 2428 | |
28f95cbc | 2429 | if (unlikely(cfqd->active_queue == cfqq)) { |
812df48d | 2430 | __cfq_slice_expired(cfqd, cfqq, 0, false); |
23e018a1 | 2431 | cfq_schedule_dispatch(cfqd); |
28f95cbc | 2432 | } |
22e2c507 | 2433 | |
f04a6424 | 2434 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
1da177e4 | 2435 | kmem_cache_free(cfq_pool, cfqq); |
b1c35769 | 2436 | cfq_put_cfqg(cfqg); |
878eaddd VG |
2437 | if (orig_cfqg) |
2438 | cfq_put_cfqg(orig_cfqg); | |
1da177e4 LT |
2439 | } |
2440 | ||
d6de8be7 JA |
2441 | /* |
2442 | * Must always be called with the rcu_read_lock() held | |
2443 | */ | |
07416d29 JA |
2444 | static void |
2445 | __call_for_each_cic(struct io_context *ioc, | |
2446 | void (*func)(struct io_context *, struct cfq_io_context *)) | |
2447 | { | |
2448 | struct cfq_io_context *cic; | |
2449 | struct hlist_node *n; | |
2450 | ||
2451 | hlist_for_each_entry_rcu(cic, n, &ioc->cic_list, cic_list) | |
2452 | func(ioc, cic); | |
2453 | } | |
2454 | ||
4ac845a2 | 2455 | /* |
34e6bbf2 | 2456 | * Call func for each cic attached to this ioc. |
4ac845a2 | 2457 | */ |
34e6bbf2 | 2458 | static void |
4ac845a2 JA |
2459 | call_for_each_cic(struct io_context *ioc, |
2460 | void (*func)(struct io_context *, struct cfq_io_context *)) | |
1da177e4 | 2461 | { |
4ac845a2 | 2462 | rcu_read_lock(); |
07416d29 | 2463 | __call_for_each_cic(ioc, func); |
4ac845a2 | 2464 | rcu_read_unlock(); |
34e6bbf2 FC |
2465 | } |
2466 | ||
2467 | static void cfq_cic_free_rcu(struct rcu_head *head) | |
2468 | { | |
2469 | struct cfq_io_context *cic; | |
2470 | ||
2471 | cic = container_of(head, struct cfq_io_context, rcu_head); | |
2472 | ||
2473 | kmem_cache_free(cfq_ioc_pool, cic); | |
245b2e70 | 2474 | elv_ioc_count_dec(cfq_ioc_count); |
34e6bbf2 | 2475 | |
9a11b4ed JA |
2476 | if (ioc_gone) { |
2477 | /* | |
2478 | * CFQ scheduler is exiting, grab exit lock and check | |
2479 | * the pending io context count. If it hits zero, | |
2480 | * complete ioc_gone and set it back to NULL | |
2481 | */ | |
2482 | spin_lock(&ioc_gone_lock); | |
245b2e70 | 2483 | if (ioc_gone && !elv_ioc_count_read(cfq_ioc_count)) { |
9a11b4ed JA |
2484 | complete(ioc_gone); |
2485 | ioc_gone = NULL; | |
2486 | } | |
2487 | spin_unlock(&ioc_gone_lock); | |
2488 | } | |
34e6bbf2 | 2489 | } |
4ac845a2 | 2490 | |
34e6bbf2 FC |
2491 | static void cfq_cic_free(struct cfq_io_context *cic) |
2492 | { | |
2493 | call_rcu(&cic->rcu_head, cfq_cic_free_rcu); | |
4ac845a2 JA |
2494 | } |
2495 | ||
2496 | static void cic_free_func(struct io_context *ioc, struct cfq_io_context *cic) | |
2497 | { | |
2498 | unsigned long flags; | |
2499 | ||
2500 | BUG_ON(!cic->dead_key); | |
2501 | ||
2502 | spin_lock_irqsave(&ioc->lock, flags); | |
2503 | radix_tree_delete(&ioc->radix_root, cic->dead_key); | |
ffc4e759 | 2504 | hlist_del_rcu(&cic->cic_list); |
4ac845a2 JA |
2505 | spin_unlock_irqrestore(&ioc->lock, flags); |
2506 | ||
34e6bbf2 | 2507 | cfq_cic_free(cic); |
4ac845a2 JA |
2508 | } |
2509 | ||
d6de8be7 JA |
2510 | /* |
2511 | * Must be called with rcu_read_lock() held or preemption otherwise disabled. | |
2512 | * Only two callers of this - ->dtor() which is called with the rcu_read_lock(), | |
2513 | * and ->trim() which is called with the task lock held | |
2514 | */ | |
4ac845a2 JA |
2515 | static void cfq_free_io_context(struct io_context *ioc) |
2516 | { | |
4ac845a2 | 2517 | /* |
34e6bbf2 FC |
2518 | * ioc->refcount is zero here, or we are called from elv_unregister(), |
2519 | * so no more cic's are allowed to be linked into this ioc. So it | |
2520 | * should be ok to iterate over the known list, we will see all cic's | |
2521 | * since no new ones are added. | |
4ac845a2 | 2522 | */ |
07416d29 | 2523 | __call_for_each_cic(ioc, cic_free_func); |
1da177e4 LT |
2524 | } |
2525 | ||
89850f7e | 2526 | static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 2527 | { |
df5fe3e8 JM |
2528 | struct cfq_queue *__cfqq, *next; |
2529 | ||
28f95cbc | 2530 | if (unlikely(cfqq == cfqd->active_queue)) { |
812df48d | 2531 | __cfq_slice_expired(cfqd, cfqq, 0, false); |
23e018a1 | 2532 | cfq_schedule_dispatch(cfqd); |
28f95cbc | 2533 | } |
22e2c507 | 2534 | |
df5fe3e8 JM |
2535 | /* |
2536 | * If this queue was scheduled to merge with another queue, be | |
2537 | * sure to drop the reference taken on that queue (and others in | |
2538 | * the merge chain). See cfq_setup_merge and cfq_merge_cfqqs. | |
2539 | */ | |
2540 | __cfqq = cfqq->new_cfqq; | |
2541 | while (__cfqq) { | |
2542 | if (__cfqq == cfqq) { | |
2543 | WARN(1, "cfqq->new_cfqq loop detected\n"); | |
2544 | break; | |
2545 | } | |
2546 | next = __cfqq->new_cfqq; | |
2547 | cfq_put_queue(__cfqq); | |
2548 | __cfqq = next; | |
2549 | } | |
2550 | ||
89850f7e JA |
2551 | cfq_put_queue(cfqq); |
2552 | } | |
22e2c507 | 2553 | |
89850f7e JA |
2554 | static void __cfq_exit_single_io_context(struct cfq_data *cfqd, |
2555 | struct cfq_io_context *cic) | |
2556 | { | |
4faa3c81 FC |
2557 | struct io_context *ioc = cic->ioc; |
2558 | ||
fc46379d | 2559 | list_del_init(&cic->queue_list); |
4ac845a2 JA |
2560 | |
2561 | /* | |
2562 | * Make sure key == NULL is seen for dead queues | |
2563 | */ | |
fc46379d | 2564 | smp_wmb(); |
4ac845a2 | 2565 | cic->dead_key = (unsigned long) cic->key; |
fc46379d JA |
2566 | cic->key = NULL; |
2567 | ||
4faa3c81 FC |
2568 | if (ioc->ioc_data == cic) |
2569 | rcu_assign_pointer(ioc->ioc_data, NULL); | |
2570 | ||
ff6657c6 JA |
2571 | if (cic->cfqq[BLK_RW_ASYNC]) { |
2572 | cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_ASYNC]); | |
2573 | cic->cfqq[BLK_RW_ASYNC] = NULL; | |
12a05732 AV |
2574 | } |
2575 | ||
ff6657c6 JA |
2576 | if (cic->cfqq[BLK_RW_SYNC]) { |
2577 | cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_SYNC]); | |
2578 | cic->cfqq[BLK_RW_SYNC] = NULL; | |
12a05732 | 2579 | } |
89850f7e JA |
2580 | } |
2581 | ||
4ac845a2 JA |
2582 | static void cfq_exit_single_io_context(struct io_context *ioc, |
2583 | struct cfq_io_context *cic) | |
89850f7e JA |
2584 | { |
2585 | struct cfq_data *cfqd = cic->key; | |
2586 | ||
89850f7e | 2587 | if (cfqd) { |
165125e1 | 2588 | struct request_queue *q = cfqd->queue; |
4ac845a2 | 2589 | unsigned long flags; |
89850f7e | 2590 | |
4ac845a2 | 2591 | spin_lock_irqsave(q->queue_lock, flags); |
62c1fe9d JA |
2592 | |
2593 | /* | |
2594 | * Ensure we get a fresh copy of the ->key to prevent | |
2595 | * race between exiting task and queue | |
2596 | */ | |
2597 | smp_read_barrier_depends(); | |
2598 | if (cic->key) | |
2599 | __cfq_exit_single_io_context(cfqd, cic); | |
2600 | ||
4ac845a2 | 2601 | spin_unlock_irqrestore(q->queue_lock, flags); |
89850f7e | 2602 | } |
1da177e4 LT |
2603 | } |
2604 | ||
498d3aa2 JA |
2605 | /* |
2606 | * The process that ioc belongs to has exited, we need to clean up | |
2607 | * and put the internal structures we have that belongs to that process. | |
2608 | */ | |
e2d74ac0 | 2609 | static void cfq_exit_io_context(struct io_context *ioc) |
1da177e4 | 2610 | { |
4ac845a2 | 2611 | call_for_each_cic(ioc, cfq_exit_single_io_context); |
1da177e4 LT |
2612 | } |
2613 | ||
22e2c507 | 2614 | static struct cfq_io_context * |
8267e268 | 2615 | cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
1da177e4 | 2616 | { |
b5deef90 | 2617 | struct cfq_io_context *cic; |
1da177e4 | 2618 | |
94f6030c CL |
2619 | cic = kmem_cache_alloc_node(cfq_ioc_pool, gfp_mask | __GFP_ZERO, |
2620 | cfqd->queue->node); | |
1da177e4 | 2621 | if (cic) { |
22e2c507 | 2622 | cic->last_end_request = jiffies; |
553698f9 | 2623 | INIT_LIST_HEAD(&cic->queue_list); |
ffc4e759 | 2624 | INIT_HLIST_NODE(&cic->cic_list); |
22e2c507 JA |
2625 | cic->dtor = cfq_free_io_context; |
2626 | cic->exit = cfq_exit_io_context; | |
245b2e70 | 2627 | elv_ioc_count_inc(cfq_ioc_count); |
1da177e4 LT |
2628 | } |
2629 | ||
2630 | return cic; | |
2631 | } | |
2632 | ||
fd0928df | 2633 | static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc) |
22e2c507 JA |
2634 | { |
2635 | struct task_struct *tsk = current; | |
2636 | int ioprio_class; | |
2637 | ||
3b18152c | 2638 | if (!cfq_cfqq_prio_changed(cfqq)) |
22e2c507 JA |
2639 | return; |
2640 | ||
fd0928df | 2641 | ioprio_class = IOPRIO_PRIO_CLASS(ioc->ioprio); |
22e2c507 | 2642 | switch (ioprio_class) { |
fe094d98 JA |
2643 | default: |
2644 | printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class); | |
2645 | case IOPRIO_CLASS_NONE: | |
2646 | /* | |
6d63c275 | 2647 | * no prio set, inherit CPU scheduling settings |
fe094d98 JA |
2648 | */ |
2649 | cfqq->ioprio = task_nice_ioprio(tsk); | |
6d63c275 | 2650 | cfqq->ioprio_class = task_nice_ioclass(tsk); |
fe094d98 JA |
2651 | break; |
2652 | case IOPRIO_CLASS_RT: | |
2653 | cfqq->ioprio = task_ioprio(ioc); | |
2654 | cfqq->ioprio_class = IOPRIO_CLASS_RT; | |
2655 | break; | |
2656 | case IOPRIO_CLASS_BE: | |
2657 | cfqq->ioprio = task_ioprio(ioc); | |
2658 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
2659 | break; | |
2660 | case IOPRIO_CLASS_IDLE: | |
2661 | cfqq->ioprio_class = IOPRIO_CLASS_IDLE; | |
2662 | cfqq->ioprio = 7; | |
2663 | cfq_clear_cfqq_idle_window(cfqq); | |
2664 | break; | |
22e2c507 JA |
2665 | } |
2666 | ||
2667 | /* | |
2668 | * keep track of original prio settings in case we have to temporarily | |
2669 | * elevate the priority of this queue | |
2670 | */ | |
2671 | cfqq->org_ioprio = cfqq->ioprio; | |
2672 | cfqq->org_ioprio_class = cfqq->ioprio_class; | |
3b18152c | 2673 | cfq_clear_cfqq_prio_changed(cfqq); |
22e2c507 JA |
2674 | } |
2675 | ||
febffd61 | 2676 | static void changed_ioprio(struct io_context *ioc, struct cfq_io_context *cic) |
22e2c507 | 2677 | { |
478a82b0 AV |
2678 | struct cfq_data *cfqd = cic->key; |
2679 | struct cfq_queue *cfqq; | |
c1b707d2 | 2680 | unsigned long flags; |
35e6077c | 2681 | |
caaa5f9f JA |
2682 | if (unlikely(!cfqd)) |
2683 | return; | |
2684 | ||
c1b707d2 | 2685 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); |
caaa5f9f | 2686 | |
ff6657c6 | 2687 | cfqq = cic->cfqq[BLK_RW_ASYNC]; |
caaa5f9f JA |
2688 | if (cfqq) { |
2689 | struct cfq_queue *new_cfqq; | |
ff6657c6 JA |
2690 | new_cfqq = cfq_get_queue(cfqd, BLK_RW_ASYNC, cic->ioc, |
2691 | GFP_ATOMIC); | |
caaa5f9f | 2692 | if (new_cfqq) { |
ff6657c6 | 2693 | cic->cfqq[BLK_RW_ASYNC] = new_cfqq; |
caaa5f9f JA |
2694 | cfq_put_queue(cfqq); |
2695 | } | |
22e2c507 | 2696 | } |
caaa5f9f | 2697 | |
ff6657c6 | 2698 | cfqq = cic->cfqq[BLK_RW_SYNC]; |
caaa5f9f JA |
2699 | if (cfqq) |
2700 | cfq_mark_cfqq_prio_changed(cfqq); | |
2701 | ||
c1b707d2 | 2702 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); |
22e2c507 JA |
2703 | } |
2704 | ||
fc46379d | 2705 | static void cfq_ioc_set_ioprio(struct io_context *ioc) |
22e2c507 | 2706 | { |
4ac845a2 | 2707 | call_for_each_cic(ioc, changed_ioprio); |
fc46379d | 2708 | ioc->ioprio_changed = 0; |
22e2c507 JA |
2709 | } |
2710 | ||
d5036d77 | 2711 | static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
a6151c3a | 2712 | pid_t pid, bool is_sync) |
d5036d77 JA |
2713 | { |
2714 | RB_CLEAR_NODE(&cfqq->rb_node); | |
2715 | RB_CLEAR_NODE(&cfqq->p_node); | |
2716 | INIT_LIST_HEAD(&cfqq->fifo); | |
2717 | ||
2718 | atomic_set(&cfqq->ref, 0); | |
2719 | cfqq->cfqd = cfqd; | |
2720 | ||
2721 | cfq_mark_cfqq_prio_changed(cfqq); | |
2722 | ||
2723 | if (is_sync) { | |
2724 | if (!cfq_class_idle(cfqq)) | |
2725 | cfq_mark_cfqq_idle_window(cfqq); | |
2726 | cfq_mark_cfqq_sync(cfqq); | |
2727 | } | |
2728 | cfqq->pid = pid; | |
2729 | } | |
2730 | ||
24610333 VG |
2731 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
2732 | static void changed_cgroup(struct io_context *ioc, struct cfq_io_context *cic) | |
2733 | { | |
2734 | struct cfq_queue *sync_cfqq = cic_to_cfqq(cic, 1); | |
2735 | struct cfq_data *cfqd = cic->key; | |
2736 | unsigned long flags; | |
2737 | struct request_queue *q; | |
2738 | ||
2739 | if (unlikely(!cfqd)) | |
2740 | return; | |
2741 | ||
2742 | q = cfqd->queue; | |
2743 | ||
2744 | spin_lock_irqsave(q->queue_lock, flags); | |
2745 | ||
2746 | if (sync_cfqq) { | |
2747 | /* | |
2748 | * Drop reference to sync queue. A new sync queue will be | |
2749 | * assigned in new group upon arrival of a fresh request. | |
2750 | */ | |
2751 | cfq_log_cfqq(cfqd, sync_cfqq, "changed cgroup"); | |
2752 | cic_set_cfqq(cic, NULL, 1); | |
2753 | cfq_put_queue(sync_cfqq); | |
2754 | } | |
2755 | ||
2756 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2757 | } | |
2758 | ||
2759 | static void cfq_ioc_set_cgroup(struct io_context *ioc) | |
2760 | { | |
2761 | call_for_each_cic(ioc, changed_cgroup); | |
2762 | ioc->cgroup_changed = 0; | |
2763 | } | |
2764 | #endif /* CONFIG_CFQ_GROUP_IOSCHED */ | |
2765 | ||
22e2c507 | 2766 | static struct cfq_queue * |
a6151c3a | 2767 | cfq_find_alloc_queue(struct cfq_data *cfqd, bool is_sync, |
fd0928df | 2768 | struct io_context *ioc, gfp_t gfp_mask) |
22e2c507 | 2769 | { |
22e2c507 | 2770 | struct cfq_queue *cfqq, *new_cfqq = NULL; |
91fac317 | 2771 | struct cfq_io_context *cic; |
cdb16e8f | 2772 | struct cfq_group *cfqg; |
22e2c507 JA |
2773 | |
2774 | retry: | |
cdb16e8f | 2775 | cfqg = cfq_get_cfqg(cfqd, 1); |
4ac845a2 | 2776 | cic = cfq_cic_lookup(cfqd, ioc); |
91fac317 VT |
2777 | /* cic always exists here */ |
2778 | cfqq = cic_to_cfqq(cic, is_sync); | |
22e2c507 | 2779 | |
6118b70b JA |
2780 | /* |
2781 | * Always try a new alloc if we fell back to the OOM cfqq | |
2782 | * originally, since it should just be a temporary situation. | |
2783 | */ | |
2784 | if (!cfqq || cfqq == &cfqd->oom_cfqq) { | |
2785 | cfqq = NULL; | |
22e2c507 JA |
2786 | if (new_cfqq) { |
2787 | cfqq = new_cfqq; | |
2788 | new_cfqq = NULL; | |
2789 | } else if (gfp_mask & __GFP_WAIT) { | |
2790 | spin_unlock_irq(cfqd->queue->queue_lock); | |
94f6030c | 2791 | new_cfqq = kmem_cache_alloc_node(cfq_pool, |
6118b70b | 2792 | gfp_mask | __GFP_ZERO, |
94f6030c | 2793 | cfqd->queue->node); |
22e2c507 | 2794 | spin_lock_irq(cfqd->queue->queue_lock); |
6118b70b JA |
2795 | if (new_cfqq) |
2796 | goto retry; | |
22e2c507 | 2797 | } else { |
94f6030c CL |
2798 | cfqq = kmem_cache_alloc_node(cfq_pool, |
2799 | gfp_mask | __GFP_ZERO, | |
2800 | cfqd->queue->node); | |
22e2c507 JA |
2801 | } |
2802 | ||
6118b70b JA |
2803 | if (cfqq) { |
2804 | cfq_init_cfqq(cfqd, cfqq, current->pid, is_sync); | |
2805 | cfq_init_prio_data(cfqq, ioc); | |
cdb16e8f | 2806 | cfq_link_cfqq_cfqg(cfqq, cfqg); |
6118b70b JA |
2807 | cfq_log_cfqq(cfqd, cfqq, "alloced"); |
2808 | } else | |
2809 | cfqq = &cfqd->oom_cfqq; | |
22e2c507 JA |
2810 | } |
2811 | ||
2812 | if (new_cfqq) | |
2813 | kmem_cache_free(cfq_pool, new_cfqq); | |
2814 | ||
22e2c507 JA |
2815 | return cfqq; |
2816 | } | |
2817 | ||
c2dea2d1 VT |
2818 | static struct cfq_queue ** |
2819 | cfq_async_queue_prio(struct cfq_data *cfqd, int ioprio_class, int ioprio) | |
2820 | { | |
fe094d98 | 2821 | switch (ioprio_class) { |
c2dea2d1 VT |
2822 | case IOPRIO_CLASS_RT: |
2823 | return &cfqd->async_cfqq[0][ioprio]; | |
2824 | case IOPRIO_CLASS_BE: | |
2825 | return &cfqd->async_cfqq[1][ioprio]; | |
2826 | case IOPRIO_CLASS_IDLE: | |
2827 | return &cfqd->async_idle_cfqq; | |
2828 | default: | |
2829 | BUG(); | |
2830 | } | |
2831 | } | |
2832 | ||
15c31be4 | 2833 | static struct cfq_queue * |
a6151c3a | 2834 | cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct io_context *ioc, |
15c31be4 JA |
2835 | gfp_t gfp_mask) |
2836 | { | |
fd0928df JA |
2837 | const int ioprio = task_ioprio(ioc); |
2838 | const int ioprio_class = task_ioprio_class(ioc); | |
c2dea2d1 | 2839 | struct cfq_queue **async_cfqq = NULL; |
15c31be4 JA |
2840 | struct cfq_queue *cfqq = NULL; |
2841 | ||
c2dea2d1 VT |
2842 | if (!is_sync) { |
2843 | async_cfqq = cfq_async_queue_prio(cfqd, ioprio_class, ioprio); | |
2844 | cfqq = *async_cfqq; | |
2845 | } | |
2846 | ||
6118b70b | 2847 | if (!cfqq) |
fd0928df | 2848 | cfqq = cfq_find_alloc_queue(cfqd, is_sync, ioc, gfp_mask); |
15c31be4 JA |
2849 | |
2850 | /* | |
2851 | * pin the queue now that it's allocated, scheduler exit will prune it | |
2852 | */ | |
c2dea2d1 | 2853 | if (!is_sync && !(*async_cfqq)) { |
15c31be4 | 2854 | atomic_inc(&cfqq->ref); |
c2dea2d1 | 2855 | *async_cfqq = cfqq; |
15c31be4 JA |
2856 | } |
2857 | ||
2858 | atomic_inc(&cfqq->ref); | |
2859 | return cfqq; | |
2860 | } | |
2861 | ||
498d3aa2 JA |
2862 | /* |
2863 | * We drop cfq io contexts lazily, so we may find a dead one. | |
2864 | */ | |
dbecf3ab | 2865 | static void |
4ac845a2 JA |
2866 | cfq_drop_dead_cic(struct cfq_data *cfqd, struct io_context *ioc, |
2867 | struct cfq_io_context *cic) | |
dbecf3ab | 2868 | { |
4ac845a2 JA |
2869 | unsigned long flags; |
2870 | ||
fc46379d | 2871 | WARN_ON(!list_empty(&cic->queue_list)); |
597bc485 | 2872 | |
4ac845a2 JA |
2873 | spin_lock_irqsave(&ioc->lock, flags); |
2874 | ||
4faa3c81 | 2875 | BUG_ON(ioc->ioc_data == cic); |
597bc485 | 2876 | |
4ac845a2 | 2877 | radix_tree_delete(&ioc->radix_root, (unsigned long) cfqd); |
ffc4e759 | 2878 | hlist_del_rcu(&cic->cic_list); |
4ac845a2 JA |
2879 | spin_unlock_irqrestore(&ioc->lock, flags); |
2880 | ||
2881 | cfq_cic_free(cic); | |
dbecf3ab OH |
2882 | } |
2883 | ||
e2d74ac0 | 2884 | static struct cfq_io_context * |
4ac845a2 | 2885 | cfq_cic_lookup(struct cfq_data *cfqd, struct io_context *ioc) |
e2d74ac0 | 2886 | { |
e2d74ac0 | 2887 | struct cfq_io_context *cic; |
d6de8be7 | 2888 | unsigned long flags; |
4ac845a2 | 2889 | void *k; |
e2d74ac0 | 2890 | |
91fac317 VT |
2891 | if (unlikely(!ioc)) |
2892 | return NULL; | |
2893 | ||
d6de8be7 JA |
2894 | rcu_read_lock(); |
2895 | ||
597bc485 JA |
2896 | /* |
2897 | * we maintain a last-hit cache, to avoid browsing over the tree | |
2898 | */ | |
4ac845a2 | 2899 | cic = rcu_dereference(ioc->ioc_data); |
d6de8be7 JA |
2900 | if (cic && cic->key == cfqd) { |
2901 | rcu_read_unlock(); | |
597bc485 | 2902 | return cic; |
d6de8be7 | 2903 | } |
597bc485 | 2904 | |
4ac845a2 | 2905 | do { |
4ac845a2 JA |
2906 | cic = radix_tree_lookup(&ioc->radix_root, (unsigned long) cfqd); |
2907 | rcu_read_unlock(); | |
2908 | if (!cic) | |
2909 | break; | |
be3b0753 OH |
2910 | /* ->key must be copied to avoid race with cfq_exit_queue() */ |
2911 | k = cic->key; | |
2912 | if (unlikely(!k)) { | |
4ac845a2 | 2913 | cfq_drop_dead_cic(cfqd, ioc, cic); |
d6de8be7 | 2914 | rcu_read_lock(); |
4ac845a2 | 2915 | continue; |
dbecf3ab | 2916 | } |
e2d74ac0 | 2917 | |
d6de8be7 | 2918 | spin_lock_irqsave(&ioc->lock, flags); |
4ac845a2 | 2919 | rcu_assign_pointer(ioc->ioc_data, cic); |
d6de8be7 | 2920 | spin_unlock_irqrestore(&ioc->lock, flags); |
4ac845a2 JA |
2921 | break; |
2922 | } while (1); | |
e2d74ac0 | 2923 | |
4ac845a2 | 2924 | return cic; |
e2d74ac0 JA |
2925 | } |
2926 | ||
4ac845a2 JA |
2927 | /* |
2928 | * Add cic into ioc, using cfqd as the search key. This enables us to lookup | |
2929 | * the process specific cfq io context when entered from the block layer. | |
2930 | * Also adds the cic to a per-cfqd list, used when this queue is removed. | |
2931 | */ | |
febffd61 JA |
2932 | static int cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc, |
2933 | struct cfq_io_context *cic, gfp_t gfp_mask) | |
e2d74ac0 | 2934 | { |
0261d688 | 2935 | unsigned long flags; |
4ac845a2 | 2936 | int ret; |
e2d74ac0 | 2937 | |
4ac845a2 JA |
2938 | ret = radix_tree_preload(gfp_mask); |
2939 | if (!ret) { | |
2940 | cic->ioc = ioc; | |
2941 | cic->key = cfqd; | |
e2d74ac0 | 2942 | |
4ac845a2 JA |
2943 | spin_lock_irqsave(&ioc->lock, flags); |
2944 | ret = radix_tree_insert(&ioc->radix_root, | |
2945 | (unsigned long) cfqd, cic); | |
ffc4e759 JA |
2946 | if (!ret) |
2947 | hlist_add_head_rcu(&cic->cic_list, &ioc->cic_list); | |
4ac845a2 | 2948 | spin_unlock_irqrestore(&ioc->lock, flags); |
e2d74ac0 | 2949 | |
4ac845a2 JA |
2950 | radix_tree_preload_end(); |
2951 | ||
2952 | if (!ret) { | |
2953 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
2954 | list_add(&cic->queue_list, &cfqd->cic_list); | |
2955 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
2956 | } | |
e2d74ac0 JA |
2957 | } |
2958 | ||
4ac845a2 JA |
2959 | if (ret) |
2960 | printk(KERN_ERR "cfq: cic link failed!\n"); | |
fc46379d | 2961 | |
4ac845a2 | 2962 | return ret; |
e2d74ac0 JA |
2963 | } |
2964 | ||
1da177e4 LT |
2965 | /* |
2966 | * Setup general io context and cfq io context. There can be several cfq | |
2967 | * io contexts per general io context, if this process is doing io to more | |
e2d74ac0 | 2968 | * than one device managed by cfq. |
1da177e4 LT |
2969 | */ |
2970 | static struct cfq_io_context * | |
e2d74ac0 | 2971 | cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
1da177e4 | 2972 | { |
22e2c507 | 2973 | struct io_context *ioc = NULL; |
1da177e4 | 2974 | struct cfq_io_context *cic; |
1da177e4 | 2975 | |
22e2c507 | 2976 | might_sleep_if(gfp_mask & __GFP_WAIT); |
1da177e4 | 2977 | |
b5deef90 | 2978 | ioc = get_io_context(gfp_mask, cfqd->queue->node); |
1da177e4 LT |
2979 | if (!ioc) |
2980 | return NULL; | |
2981 | ||
4ac845a2 | 2982 | cic = cfq_cic_lookup(cfqd, ioc); |
e2d74ac0 JA |
2983 | if (cic) |
2984 | goto out; | |
1da177e4 | 2985 | |
e2d74ac0 JA |
2986 | cic = cfq_alloc_io_context(cfqd, gfp_mask); |
2987 | if (cic == NULL) | |
2988 | goto err; | |
1da177e4 | 2989 | |
4ac845a2 JA |
2990 | if (cfq_cic_link(cfqd, ioc, cic, gfp_mask)) |
2991 | goto err_free; | |
2992 | ||
1da177e4 | 2993 | out: |
fc46379d JA |
2994 | smp_read_barrier_depends(); |
2995 | if (unlikely(ioc->ioprio_changed)) | |
2996 | cfq_ioc_set_ioprio(ioc); | |
2997 | ||
24610333 VG |
2998 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
2999 | if (unlikely(ioc->cgroup_changed)) | |
3000 | cfq_ioc_set_cgroup(ioc); | |
3001 | #endif | |
1da177e4 | 3002 | return cic; |
4ac845a2 JA |
3003 | err_free: |
3004 | cfq_cic_free(cic); | |
1da177e4 LT |
3005 | err: |
3006 | put_io_context(ioc); | |
3007 | return NULL; | |
3008 | } | |
3009 | ||
22e2c507 JA |
3010 | static void |
3011 | cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic) | |
1da177e4 | 3012 | { |
aaf1228d JA |
3013 | unsigned long elapsed = jiffies - cic->last_end_request; |
3014 | unsigned long ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle); | |
db3b5848 | 3015 | |
22e2c507 JA |
3016 | cic->ttime_samples = (7*cic->ttime_samples + 256) / 8; |
3017 | cic->ttime_total = (7*cic->ttime_total + 256*ttime) / 8; | |
3018 | cic->ttime_mean = (cic->ttime_total + 128) / cic->ttime_samples; | |
3019 | } | |
1da177e4 | 3020 | |
206dc69b | 3021 | static void |
b2c18e1e | 3022 | cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
6d048f53 | 3023 | struct request *rq) |
206dc69b | 3024 | { |
3dde36dd | 3025 | sector_t sdist = 0; |
41647e7a | 3026 | sector_t n_sec = blk_rq_sectors(rq); |
3dde36dd CZ |
3027 | if (cfqq->last_request_pos) { |
3028 | if (cfqq->last_request_pos < blk_rq_pos(rq)) | |
3029 | sdist = blk_rq_pos(rq) - cfqq->last_request_pos; | |
3030 | else | |
3031 | sdist = cfqq->last_request_pos - blk_rq_pos(rq); | |
3032 | } | |
206dc69b | 3033 | |
3dde36dd | 3034 | cfqq->seek_history <<= 1; |
41647e7a CZ |
3035 | if (blk_queue_nonrot(cfqd->queue)) |
3036 | cfqq->seek_history |= (n_sec < CFQQ_SECT_THR_NONROT); | |
3037 | else | |
3038 | cfqq->seek_history |= (sdist > CFQQ_SEEK_THR); | |
206dc69b | 3039 | } |
1da177e4 | 3040 | |
22e2c507 JA |
3041 | /* |
3042 | * Disable idle window if the process thinks too long or seeks so much that | |
3043 | * it doesn't matter | |
3044 | */ | |
3045 | static void | |
3046 | cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
3047 | struct cfq_io_context *cic) | |
3048 | { | |
7b679138 | 3049 | int old_idle, enable_idle; |
1be92f2f | 3050 | |
0871714e JA |
3051 | /* |
3052 | * Don't idle for async or idle io prio class | |
3053 | */ | |
3054 | if (!cfq_cfqq_sync(cfqq) || cfq_class_idle(cfqq)) | |
1be92f2f JA |
3055 | return; |
3056 | ||
c265a7f4 | 3057 | enable_idle = old_idle = cfq_cfqq_idle_window(cfqq); |
1da177e4 | 3058 | |
76280aff CZ |
3059 | if (cfqq->queued[0] + cfqq->queued[1] >= 4) |
3060 | cfq_mark_cfqq_deep(cfqq); | |
3061 | ||
66dac98e | 3062 | if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle || |
3dde36dd | 3063 | (!cfq_cfqq_deep(cfqq) && CFQQ_SEEKY(cfqq))) |
22e2c507 JA |
3064 | enable_idle = 0; |
3065 | else if (sample_valid(cic->ttime_samples)) { | |
718eee05 | 3066 | if (cic->ttime_mean > cfqd->cfq_slice_idle) |
22e2c507 JA |
3067 | enable_idle = 0; |
3068 | else | |
3069 | enable_idle = 1; | |
1da177e4 LT |
3070 | } |
3071 | ||
7b679138 JA |
3072 | if (old_idle != enable_idle) { |
3073 | cfq_log_cfqq(cfqd, cfqq, "idle=%d", enable_idle); | |
3074 | if (enable_idle) | |
3075 | cfq_mark_cfqq_idle_window(cfqq); | |
3076 | else | |
3077 | cfq_clear_cfqq_idle_window(cfqq); | |
3078 | } | |
22e2c507 | 3079 | } |
1da177e4 | 3080 | |
22e2c507 JA |
3081 | /* |
3082 | * Check if new_cfqq should preempt the currently active queue. Return 0 for | |
3083 | * no or if we aren't sure, a 1 will cause a preempt. | |
3084 | */ | |
a6151c3a | 3085 | static bool |
22e2c507 | 3086 | cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, |
5e705374 | 3087 | struct request *rq) |
22e2c507 | 3088 | { |
6d048f53 | 3089 | struct cfq_queue *cfqq; |
22e2c507 | 3090 | |
6d048f53 JA |
3091 | cfqq = cfqd->active_queue; |
3092 | if (!cfqq) | |
a6151c3a | 3093 | return false; |
22e2c507 | 3094 | |
6d048f53 | 3095 | if (cfq_class_idle(new_cfqq)) |
a6151c3a | 3096 | return false; |
22e2c507 JA |
3097 | |
3098 | if (cfq_class_idle(cfqq)) | |
a6151c3a | 3099 | return true; |
1e3335de | 3100 | |
875feb63 DS |
3101 | /* |
3102 | * Don't allow a non-RT request to preempt an ongoing RT cfqq timeslice. | |
3103 | */ | |
3104 | if (cfq_class_rt(cfqq) && !cfq_class_rt(new_cfqq)) | |
3105 | return false; | |
3106 | ||
374f84ac JA |
3107 | /* |
3108 | * if the new request is sync, but the currently running queue is | |
3109 | * not, let the sync request have priority. | |
3110 | */ | |
5e705374 | 3111 | if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq)) |
a6151c3a | 3112 | return true; |
1e3335de | 3113 | |
8682e1f1 VG |
3114 | if (new_cfqq->cfqg != cfqq->cfqg) |
3115 | return false; | |
3116 | ||
3117 | if (cfq_slice_used(cfqq)) | |
3118 | return true; | |
3119 | ||
3120 | /* Allow preemption only if we are idling on sync-noidle tree */ | |
3121 | if (cfqd->serving_type == SYNC_NOIDLE_WORKLOAD && | |
3122 | cfqq_type(new_cfqq) == SYNC_NOIDLE_WORKLOAD && | |
3123 | new_cfqq->service_tree->count == 2 && | |
3124 | RB_EMPTY_ROOT(&cfqq->sort_list)) | |
3125 | return true; | |
3126 | ||
374f84ac JA |
3127 | /* |
3128 | * So both queues are sync. Let the new request get disk time if | |
3129 | * it's a metadata request and the current queue is doing regular IO. | |
3130 | */ | |
3131 | if (rq_is_meta(rq) && !cfqq->meta_pending) | |
e6ec4fe2 | 3132 | return true; |
22e2c507 | 3133 | |
3a9a3f6c DS |
3134 | /* |
3135 | * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice. | |
3136 | */ | |
3137 | if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq)) | |
a6151c3a | 3138 | return true; |
3a9a3f6c | 3139 | |
1e3335de | 3140 | if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq)) |
a6151c3a | 3141 | return false; |
1e3335de JA |
3142 | |
3143 | /* | |
3144 | * if this request is as-good as one we would expect from the | |
3145 | * current cfqq, let it preempt | |
3146 | */ | |
e9ce335d | 3147 | if (cfq_rq_close(cfqd, cfqq, rq)) |
a6151c3a | 3148 | return true; |
1e3335de | 3149 | |
a6151c3a | 3150 | return false; |
22e2c507 JA |
3151 | } |
3152 | ||
3153 | /* | |
3154 | * cfqq preempts the active queue. if we allowed preempt with no slice left, | |
3155 | * let it have half of its nominal slice. | |
3156 | */ | |
3157 | static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
3158 | { | |
7b679138 | 3159 | cfq_log_cfqq(cfqd, cfqq, "preempt"); |
812df48d | 3160 | cfq_slice_expired(cfqd, 1, false); |
22e2c507 | 3161 | |
bf572256 JA |
3162 | /* |
3163 | * Put the new queue at the front of the of the current list, | |
3164 | * so we know that it will be selected next. | |
3165 | */ | |
3166 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); | |
edd75ffd JA |
3167 | |
3168 | cfq_service_tree_add(cfqd, cfqq, 1); | |
bf572256 | 3169 | |
44f7c160 JA |
3170 | cfqq->slice_end = 0; |
3171 | cfq_mark_cfqq_slice_new(cfqq); | |
22e2c507 JA |
3172 | } |
3173 | ||
22e2c507 | 3174 | /* |
5e705374 | 3175 | * Called when a new fs request (rq) is added (to cfqq). Check if there's |
22e2c507 JA |
3176 | * something we should do about it |
3177 | */ | |
3178 | static void | |
5e705374 JA |
3179 | cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
3180 | struct request *rq) | |
22e2c507 | 3181 | { |
5e705374 | 3182 | struct cfq_io_context *cic = RQ_CIC(rq); |
12e9fddd | 3183 | |
45333d5a | 3184 | cfqd->rq_queued++; |
374f84ac JA |
3185 | if (rq_is_meta(rq)) |
3186 | cfqq->meta_pending++; | |
3187 | ||
9c2c38a1 | 3188 | cfq_update_io_thinktime(cfqd, cic); |
b2c18e1e | 3189 | cfq_update_io_seektime(cfqd, cfqq, rq); |
9c2c38a1 JA |
3190 | cfq_update_idle_window(cfqd, cfqq, cic); |
3191 | ||
b2c18e1e | 3192 | cfqq->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq); |
22e2c507 JA |
3193 | |
3194 | if (cfqq == cfqd->active_queue) { | |
3195 | /* | |
b029195d JA |
3196 | * Remember that we saw a request from this process, but |
3197 | * don't start queuing just yet. Otherwise we risk seeing lots | |
3198 | * of tiny requests, because we disrupt the normal plugging | |
d6ceb25e JA |
3199 | * and merging. If the request is already larger than a single |
3200 | * page, let it rip immediately. For that case we assume that | |
2d870722 JA |
3201 | * merging is already done. Ditto for a busy system that |
3202 | * has other work pending, don't risk delaying until the | |
3203 | * idle timer unplug to continue working. | |
22e2c507 | 3204 | */ |
d6ceb25e | 3205 | if (cfq_cfqq_wait_request(cfqq)) { |
2d870722 JA |
3206 | if (blk_rq_bytes(rq) > PAGE_CACHE_SIZE || |
3207 | cfqd->busy_queues > 1) { | |
812df48d | 3208 | cfq_del_timer(cfqd, cfqq); |
554554f6 | 3209 | cfq_clear_cfqq_wait_request(cfqq); |
bf791937 VG |
3210 | __blk_run_queue(cfqd->queue); |
3211 | } else | |
3212 | cfq_mark_cfqq_must_dispatch(cfqq); | |
d6ceb25e | 3213 | } |
5e705374 | 3214 | } else if (cfq_should_preempt(cfqd, cfqq, rq)) { |
22e2c507 JA |
3215 | /* |
3216 | * not the active queue - expire current slice if it is | |
3217 | * idle and has expired it's mean thinktime or this new queue | |
3a9a3f6c DS |
3218 | * has some old slice time left and is of higher priority or |
3219 | * this new queue is RT and the current one is BE | |
22e2c507 JA |
3220 | */ |
3221 | cfq_preempt_queue(cfqd, cfqq); | |
a7f55792 | 3222 | __blk_run_queue(cfqd->queue); |
22e2c507 | 3223 | } |
1da177e4 LT |
3224 | } |
3225 | ||
165125e1 | 3226 | static void cfq_insert_request(struct request_queue *q, struct request *rq) |
1da177e4 | 3227 | { |
b4878f24 | 3228 | struct cfq_data *cfqd = q->elevator->elevator_data; |
5e705374 | 3229 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 | 3230 | |
7b679138 | 3231 | cfq_log_cfqq(cfqd, cfqq, "insert_request"); |
fd0928df | 3232 | cfq_init_prio_data(cfqq, RQ_CIC(rq)->ioc); |
1da177e4 | 3233 | |
30996f40 | 3234 | rq_set_fifo_time(rq, jiffies + cfqd->cfq_fifo_expire[rq_is_sync(rq)]); |
22e2c507 | 3235 | list_add_tail(&rq->queuelist, &cfqq->fifo); |
aa6f6a3d | 3236 | cfq_add_rq_rb(rq); |
22e2c507 | 3237 | |
cdc1184c DS |
3238 | blkiocg_update_request_add_stats(&cfqq->cfqg->blkg, |
3239 | &cfqd->serving_group->blkg, rq_data_dir(rq), | |
3240 | rq_is_sync(rq)); | |
5e705374 | 3241 | cfq_rq_enqueued(cfqd, cfqq, rq); |
1da177e4 LT |
3242 | } |
3243 | ||
45333d5a AC |
3244 | /* |
3245 | * Update hw_tag based on peak queue depth over 50 samples under | |
3246 | * sufficient load. | |
3247 | */ | |
3248 | static void cfq_update_hw_tag(struct cfq_data *cfqd) | |
3249 | { | |
1a1238a7 SL |
3250 | struct cfq_queue *cfqq = cfqd->active_queue; |
3251 | ||
53c583d2 CZ |
3252 | if (cfqd->rq_in_driver > cfqd->hw_tag_est_depth) |
3253 | cfqd->hw_tag_est_depth = cfqd->rq_in_driver; | |
e459dd08 CZ |
3254 | |
3255 | if (cfqd->hw_tag == 1) | |
3256 | return; | |
45333d5a AC |
3257 | |
3258 | if (cfqd->rq_queued <= CFQ_HW_QUEUE_MIN && | |
53c583d2 | 3259 | cfqd->rq_in_driver <= CFQ_HW_QUEUE_MIN) |
45333d5a AC |
3260 | return; |
3261 | ||
1a1238a7 SL |
3262 | /* |
3263 | * If active queue hasn't enough requests and can idle, cfq might not | |
3264 | * dispatch sufficient requests to hardware. Don't zero hw_tag in this | |
3265 | * case | |
3266 | */ | |
3267 | if (cfqq && cfq_cfqq_idle_window(cfqq) && | |
3268 | cfqq->dispatched + cfqq->queued[0] + cfqq->queued[1] < | |
53c583d2 | 3269 | CFQ_HW_QUEUE_MIN && cfqd->rq_in_driver < CFQ_HW_QUEUE_MIN) |
1a1238a7 SL |
3270 | return; |
3271 | ||
45333d5a AC |
3272 | if (cfqd->hw_tag_samples++ < 50) |
3273 | return; | |
3274 | ||
e459dd08 | 3275 | if (cfqd->hw_tag_est_depth >= CFQ_HW_QUEUE_MIN) |
45333d5a AC |
3276 | cfqd->hw_tag = 1; |
3277 | else | |
3278 | cfqd->hw_tag = 0; | |
45333d5a AC |
3279 | } |
3280 | ||
7667aa06 VG |
3281 | static bool cfq_should_wait_busy(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
3282 | { | |
3283 | struct cfq_io_context *cic = cfqd->active_cic; | |
3284 | ||
3285 | /* If there are other queues in the group, don't wait */ | |
3286 | if (cfqq->cfqg->nr_cfqq > 1) | |
3287 | return false; | |
3288 | ||
3289 | if (cfq_slice_used(cfqq)) | |
3290 | return true; | |
3291 | ||
3292 | /* if slice left is less than think time, wait busy */ | |
3293 | if (cic && sample_valid(cic->ttime_samples) | |
3294 | && (cfqq->slice_end - jiffies < cic->ttime_mean)) | |
3295 | return true; | |
3296 | ||
3297 | /* | |
3298 | * If think times is less than a jiffy than ttime_mean=0 and above | |
3299 | * will not be true. It might happen that slice has not expired yet | |
3300 | * but will expire soon (4-5 ns) during select_queue(). To cover the | |
3301 | * case where think time is less than a jiffy, mark the queue wait | |
3302 | * busy if only 1 jiffy is left in the slice. | |
3303 | */ | |
3304 | if (cfqq->slice_end - jiffies == 1) | |
3305 | return true; | |
3306 | ||
3307 | return false; | |
3308 | } | |
3309 | ||
165125e1 | 3310 | static void cfq_completed_request(struct request_queue *q, struct request *rq) |
1da177e4 | 3311 | { |
5e705374 | 3312 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
b4878f24 | 3313 | struct cfq_data *cfqd = cfqq->cfqd; |
5380a101 | 3314 | const int sync = rq_is_sync(rq); |
b4878f24 | 3315 | unsigned long now; |
1da177e4 | 3316 | |
b4878f24 | 3317 | now = jiffies; |
2868ef7b | 3318 | cfq_log_cfqq(cfqd, cfqq, "complete rqnoidle %d", !!rq_noidle(rq)); |
1da177e4 | 3319 | |
45333d5a AC |
3320 | cfq_update_hw_tag(cfqd); |
3321 | ||
53c583d2 | 3322 | WARN_ON(!cfqd->rq_in_driver); |
6d048f53 | 3323 | WARN_ON(!cfqq->dispatched); |
53c583d2 | 3324 | cfqd->rq_in_driver--; |
6d048f53 | 3325 | cfqq->dispatched--; |
84c124da DS |
3326 | blkiocg_update_completion_stats(&cfqq->cfqg->blkg, rq_start_time_ns(rq), |
3327 | rq_io_start_time_ns(rq), rq_data_dir(rq), | |
3328 | rq_is_sync(rq)); | |
1da177e4 | 3329 | |
53c583d2 | 3330 | cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]--; |
3ed9a296 | 3331 | |
365722bb | 3332 | if (sync) { |
5e705374 | 3333 | RQ_CIC(rq)->last_end_request = now; |
573412b2 CZ |
3334 | if (!time_after(rq->start_time + cfqd->cfq_fifo_expire[1], now)) |
3335 | cfqd->last_delayed_sync = now; | |
365722bb | 3336 | } |
caaa5f9f JA |
3337 | |
3338 | /* | |
3339 | * If this is the active queue, check if it needs to be expired, | |
3340 | * or if we want to idle in case it has no pending requests. | |
3341 | */ | |
3342 | if (cfqd->active_queue == cfqq) { | |
a36e71f9 JA |
3343 | const bool cfqq_empty = RB_EMPTY_ROOT(&cfqq->sort_list); |
3344 | ||
44f7c160 JA |
3345 | if (cfq_cfqq_slice_new(cfqq)) { |
3346 | cfq_set_prio_slice(cfqd, cfqq); | |
3347 | cfq_clear_cfqq_slice_new(cfqq); | |
3348 | } | |
f75edf2d VG |
3349 | |
3350 | /* | |
7667aa06 VG |
3351 | * Should we wait for next request to come in before we expire |
3352 | * the queue. | |
f75edf2d | 3353 | */ |
7667aa06 | 3354 | if (cfq_should_wait_busy(cfqd, cfqq)) { |
f75edf2d VG |
3355 | cfqq->slice_end = jiffies + cfqd->cfq_slice_idle; |
3356 | cfq_mark_cfqq_wait_busy(cfqq); | |
b1ffe737 | 3357 | cfq_log_cfqq(cfqd, cfqq, "will busy wait"); |
f75edf2d VG |
3358 | } |
3359 | ||
a36e71f9 | 3360 | /* |
8e550632 CZ |
3361 | * Idling is not enabled on: |
3362 | * - expired queues | |
3363 | * - idle-priority queues | |
3364 | * - async queues | |
3365 | * - queues with still some requests queued | |
3366 | * - when there is a close cooperator | |
a36e71f9 | 3367 | */ |
0871714e | 3368 | if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq)) |
812df48d | 3369 | cfq_slice_expired(cfqd, 1, false); |
8e550632 CZ |
3370 | else if (sync && cfqq_empty && |
3371 | !cfq_close_cooperator(cfqd, cfqq)) { | |
3372 | cfqd->noidle_tree_requires_idle |= !rq_noidle(rq); | |
3373 | /* | |
3374 | * Idling is enabled for SYNC_WORKLOAD. | |
3375 | * SYNC_NOIDLE_WORKLOAD idles at the end of the tree | |
3376 | * only if we processed at least one !rq_noidle request | |
3377 | */ | |
3378 | if (cfqd->serving_type == SYNC_WORKLOAD | |
c04645e5 VG |
3379 | || cfqd->noidle_tree_requires_idle |
3380 | || cfqq->cfqg->nr_cfqq == 1) | |
8e550632 CZ |
3381 | cfq_arm_slice_timer(cfqd); |
3382 | } | |
caaa5f9f | 3383 | } |
6d048f53 | 3384 | |
53c583d2 | 3385 | if (!cfqd->rq_in_driver) |
23e018a1 | 3386 | cfq_schedule_dispatch(cfqd); |
1da177e4 LT |
3387 | } |
3388 | ||
22e2c507 JA |
3389 | /* |
3390 | * we temporarily boost lower priority queues if they are holding fs exclusive | |
3391 | * resources. they are boosted to normal prio (CLASS_BE/4) | |
3392 | */ | |
3393 | static void cfq_prio_boost(struct cfq_queue *cfqq) | |
1da177e4 | 3394 | { |
22e2c507 JA |
3395 | if (has_fs_excl()) { |
3396 | /* | |
3397 | * boost idle prio on transactions that would lock out other | |
3398 | * users of the filesystem | |
3399 | */ | |
3400 | if (cfq_class_idle(cfqq)) | |
3401 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
3402 | if (cfqq->ioprio > IOPRIO_NORM) | |
3403 | cfqq->ioprio = IOPRIO_NORM; | |
3404 | } else { | |
3405 | /* | |
dddb7451 | 3406 | * unboost the queue (if needed) |
22e2c507 | 3407 | */ |
dddb7451 CZ |
3408 | cfqq->ioprio_class = cfqq->org_ioprio_class; |
3409 | cfqq->ioprio = cfqq->org_ioprio; | |
22e2c507 | 3410 | } |
22e2c507 | 3411 | } |
1da177e4 | 3412 | |
89850f7e | 3413 | static inline int __cfq_may_queue(struct cfq_queue *cfqq) |
22e2c507 | 3414 | { |
1b379d8d | 3415 | if (cfq_cfqq_wait_request(cfqq) && !cfq_cfqq_must_alloc_slice(cfqq)) { |
3b18152c | 3416 | cfq_mark_cfqq_must_alloc_slice(cfqq); |
22e2c507 | 3417 | return ELV_MQUEUE_MUST; |
3b18152c | 3418 | } |
1da177e4 | 3419 | |
22e2c507 | 3420 | return ELV_MQUEUE_MAY; |
22e2c507 JA |
3421 | } |
3422 | ||
165125e1 | 3423 | static int cfq_may_queue(struct request_queue *q, int rw) |
22e2c507 JA |
3424 | { |
3425 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
3426 | struct task_struct *tsk = current; | |
91fac317 | 3427 | struct cfq_io_context *cic; |
22e2c507 JA |
3428 | struct cfq_queue *cfqq; |
3429 | ||
3430 | /* | |
3431 | * don't force setup of a queue from here, as a call to may_queue | |
3432 | * does not necessarily imply that a request actually will be queued. | |
3433 | * so just lookup a possibly existing queue, or return 'may queue' | |
3434 | * if that fails | |
3435 | */ | |
4ac845a2 | 3436 | cic = cfq_cic_lookup(cfqd, tsk->io_context); |
91fac317 VT |
3437 | if (!cic) |
3438 | return ELV_MQUEUE_MAY; | |
3439 | ||
b0b78f81 | 3440 | cfqq = cic_to_cfqq(cic, rw_is_sync(rw)); |
22e2c507 | 3441 | if (cfqq) { |
fd0928df | 3442 | cfq_init_prio_data(cfqq, cic->ioc); |
22e2c507 JA |
3443 | cfq_prio_boost(cfqq); |
3444 | ||
89850f7e | 3445 | return __cfq_may_queue(cfqq); |
22e2c507 JA |
3446 | } |
3447 | ||
3448 | return ELV_MQUEUE_MAY; | |
1da177e4 LT |
3449 | } |
3450 | ||
1da177e4 LT |
3451 | /* |
3452 | * queue lock held here | |
3453 | */ | |
bb37b94c | 3454 | static void cfq_put_request(struct request *rq) |
1da177e4 | 3455 | { |
5e705374 | 3456 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
1da177e4 | 3457 | |
5e705374 | 3458 | if (cfqq) { |
22e2c507 | 3459 | const int rw = rq_data_dir(rq); |
1da177e4 | 3460 | |
22e2c507 JA |
3461 | BUG_ON(!cfqq->allocated[rw]); |
3462 | cfqq->allocated[rw]--; | |
1da177e4 | 3463 | |
5e705374 | 3464 | put_io_context(RQ_CIC(rq)->ioc); |
1da177e4 | 3465 | |
1da177e4 | 3466 | rq->elevator_private = NULL; |
5e705374 | 3467 | rq->elevator_private2 = NULL; |
1da177e4 | 3468 | |
1da177e4 LT |
3469 | cfq_put_queue(cfqq); |
3470 | } | |
3471 | } | |
3472 | ||
df5fe3e8 JM |
3473 | static struct cfq_queue * |
3474 | cfq_merge_cfqqs(struct cfq_data *cfqd, struct cfq_io_context *cic, | |
3475 | struct cfq_queue *cfqq) | |
3476 | { | |
3477 | cfq_log_cfqq(cfqd, cfqq, "merging with queue %p", cfqq->new_cfqq); | |
3478 | cic_set_cfqq(cic, cfqq->new_cfqq, 1); | |
b3b6d040 | 3479 | cfq_mark_cfqq_coop(cfqq->new_cfqq); |
df5fe3e8 JM |
3480 | cfq_put_queue(cfqq); |
3481 | return cic_to_cfqq(cic, 1); | |
3482 | } | |
3483 | ||
e6c5bc73 JM |
3484 | /* |
3485 | * Returns NULL if a new cfqq should be allocated, or the old cfqq if this | |
3486 | * was the last process referring to said cfqq. | |
3487 | */ | |
3488 | static struct cfq_queue * | |
3489 | split_cfqq(struct cfq_io_context *cic, struct cfq_queue *cfqq) | |
3490 | { | |
3491 | if (cfqq_process_refs(cfqq) == 1) { | |
e6c5bc73 JM |
3492 | cfqq->pid = current->pid; |
3493 | cfq_clear_cfqq_coop(cfqq); | |
ae54abed | 3494 | cfq_clear_cfqq_split_coop(cfqq); |
e6c5bc73 JM |
3495 | return cfqq; |
3496 | } | |
3497 | ||
3498 | cic_set_cfqq(cic, NULL, 1); | |
3499 | cfq_put_queue(cfqq); | |
3500 | return NULL; | |
3501 | } | |
1da177e4 | 3502 | /* |
22e2c507 | 3503 | * Allocate cfq data structures associated with this request. |
1da177e4 | 3504 | */ |
22e2c507 | 3505 | static int |
165125e1 | 3506 | cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask) |
1da177e4 LT |
3507 | { |
3508 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
3509 | struct cfq_io_context *cic; | |
3510 | const int rw = rq_data_dir(rq); | |
a6151c3a | 3511 | const bool is_sync = rq_is_sync(rq); |
22e2c507 | 3512 | struct cfq_queue *cfqq; |
1da177e4 LT |
3513 | unsigned long flags; |
3514 | ||
3515 | might_sleep_if(gfp_mask & __GFP_WAIT); | |
3516 | ||
e2d74ac0 | 3517 | cic = cfq_get_io_context(cfqd, gfp_mask); |
22e2c507 | 3518 | |
1da177e4 LT |
3519 | spin_lock_irqsave(q->queue_lock, flags); |
3520 | ||
22e2c507 JA |
3521 | if (!cic) |
3522 | goto queue_fail; | |
3523 | ||
e6c5bc73 | 3524 | new_queue: |
91fac317 | 3525 | cfqq = cic_to_cfqq(cic, is_sync); |
32f2e807 | 3526 | if (!cfqq || cfqq == &cfqd->oom_cfqq) { |
fd0928df | 3527 | cfqq = cfq_get_queue(cfqd, is_sync, cic->ioc, gfp_mask); |
91fac317 | 3528 | cic_set_cfqq(cic, cfqq, is_sync); |
df5fe3e8 | 3529 | } else { |
e6c5bc73 JM |
3530 | /* |
3531 | * If the queue was seeky for too long, break it apart. | |
3532 | */ | |
ae54abed | 3533 | if (cfq_cfqq_coop(cfqq) && cfq_cfqq_split_coop(cfqq)) { |
e6c5bc73 JM |
3534 | cfq_log_cfqq(cfqd, cfqq, "breaking apart cfqq"); |
3535 | cfqq = split_cfqq(cic, cfqq); | |
3536 | if (!cfqq) | |
3537 | goto new_queue; | |
3538 | } | |
3539 | ||
df5fe3e8 JM |
3540 | /* |
3541 | * Check to see if this queue is scheduled to merge with | |
3542 | * another, closely cooperating queue. The merging of | |
3543 | * queues happens here as it must be done in process context. | |
3544 | * The reference on new_cfqq was taken in merge_cfqqs. | |
3545 | */ | |
3546 | if (cfqq->new_cfqq) | |
3547 | cfqq = cfq_merge_cfqqs(cfqd, cic, cfqq); | |
91fac317 | 3548 | } |
1da177e4 LT |
3549 | |
3550 | cfqq->allocated[rw]++; | |
22e2c507 | 3551 | atomic_inc(&cfqq->ref); |
1da177e4 | 3552 | |
5e705374 | 3553 | spin_unlock_irqrestore(q->queue_lock, flags); |
3b18152c | 3554 | |
5e705374 JA |
3555 | rq->elevator_private = cic; |
3556 | rq->elevator_private2 = cfqq; | |
3557 | return 0; | |
1da177e4 | 3558 | |
22e2c507 JA |
3559 | queue_fail: |
3560 | if (cic) | |
3561 | put_io_context(cic->ioc); | |
89850f7e | 3562 | |
23e018a1 | 3563 | cfq_schedule_dispatch(cfqd); |
1da177e4 | 3564 | spin_unlock_irqrestore(q->queue_lock, flags); |
7b679138 | 3565 | cfq_log(cfqd, "set_request fail"); |
1da177e4 LT |
3566 | return 1; |
3567 | } | |
3568 | ||
65f27f38 | 3569 | static void cfq_kick_queue(struct work_struct *work) |
22e2c507 | 3570 | { |
65f27f38 | 3571 | struct cfq_data *cfqd = |
23e018a1 | 3572 | container_of(work, struct cfq_data, unplug_work); |
165125e1 | 3573 | struct request_queue *q = cfqd->queue; |
22e2c507 | 3574 | |
40bb54d1 | 3575 | spin_lock_irq(q->queue_lock); |
a7f55792 | 3576 | __blk_run_queue(cfqd->queue); |
40bb54d1 | 3577 | spin_unlock_irq(q->queue_lock); |
22e2c507 JA |
3578 | } |
3579 | ||
3580 | /* | |
3581 | * Timer running if the active_queue is currently idling inside its time slice | |
3582 | */ | |
3583 | static void cfq_idle_slice_timer(unsigned long data) | |
3584 | { | |
3585 | struct cfq_data *cfqd = (struct cfq_data *) data; | |
3586 | struct cfq_queue *cfqq; | |
3587 | unsigned long flags; | |
3c6bd2f8 | 3588 | int timed_out = 1; |
22e2c507 | 3589 | |
7b679138 JA |
3590 | cfq_log(cfqd, "idle timer fired"); |
3591 | ||
22e2c507 JA |
3592 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); |
3593 | ||
fe094d98 JA |
3594 | cfqq = cfqd->active_queue; |
3595 | if (cfqq) { | |
3c6bd2f8 JA |
3596 | timed_out = 0; |
3597 | ||
b029195d JA |
3598 | /* |
3599 | * We saw a request before the queue expired, let it through | |
3600 | */ | |
3601 | if (cfq_cfqq_must_dispatch(cfqq)) | |
3602 | goto out_kick; | |
3603 | ||
22e2c507 JA |
3604 | /* |
3605 | * expired | |
3606 | */ | |
44f7c160 | 3607 | if (cfq_slice_used(cfqq)) |
22e2c507 JA |
3608 | goto expire; |
3609 | ||
3610 | /* | |
3611 | * only expire and reinvoke request handler, if there are | |
3612 | * other queues with pending requests | |
3613 | */ | |
caaa5f9f | 3614 | if (!cfqd->busy_queues) |
22e2c507 | 3615 | goto out_cont; |
22e2c507 JA |
3616 | |
3617 | /* | |
3618 | * not expired and it has a request pending, let it dispatch | |
3619 | */ | |
75e50984 | 3620 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
22e2c507 | 3621 | goto out_kick; |
76280aff CZ |
3622 | |
3623 | /* | |
3624 | * Queue depth flag is reset only when the idle didn't succeed | |
3625 | */ | |
3626 | cfq_clear_cfqq_deep(cfqq); | |
22e2c507 JA |
3627 | } |
3628 | expire: | |
812df48d | 3629 | cfq_slice_expired(cfqd, timed_out, false); |
22e2c507 | 3630 | out_kick: |
23e018a1 | 3631 | cfq_schedule_dispatch(cfqd); |
22e2c507 JA |
3632 | out_cont: |
3633 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
3634 | } | |
3635 | ||
3b18152c JA |
3636 | static void cfq_shutdown_timer_wq(struct cfq_data *cfqd) |
3637 | { | |
3638 | del_timer_sync(&cfqd->idle_slice_timer); | |
23e018a1 | 3639 | cancel_work_sync(&cfqd->unplug_work); |
3b18152c | 3640 | } |
22e2c507 | 3641 | |
c2dea2d1 VT |
3642 | static void cfq_put_async_queues(struct cfq_data *cfqd) |
3643 | { | |
3644 | int i; | |
3645 | ||
3646 | for (i = 0; i < IOPRIO_BE_NR; i++) { | |
3647 | if (cfqd->async_cfqq[0][i]) | |
3648 | cfq_put_queue(cfqd->async_cfqq[0][i]); | |
3649 | if (cfqd->async_cfqq[1][i]) | |
3650 | cfq_put_queue(cfqd->async_cfqq[1][i]); | |
c2dea2d1 | 3651 | } |
2389d1ef ON |
3652 | |
3653 | if (cfqd->async_idle_cfqq) | |
3654 | cfq_put_queue(cfqd->async_idle_cfqq); | |
c2dea2d1 VT |
3655 | } |
3656 | ||
bb729bc9 JA |
3657 | static void cfq_cfqd_free(struct rcu_head *head) |
3658 | { | |
3659 | kfree(container_of(head, struct cfq_data, rcu)); | |
3660 | } | |
3661 | ||
b374d18a | 3662 | static void cfq_exit_queue(struct elevator_queue *e) |
1da177e4 | 3663 | { |
22e2c507 | 3664 | struct cfq_data *cfqd = e->elevator_data; |
165125e1 | 3665 | struct request_queue *q = cfqd->queue; |
22e2c507 | 3666 | |
3b18152c | 3667 | cfq_shutdown_timer_wq(cfqd); |
e2d74ac0 | 3668 | |
d9ff4187 | 3669 | spin_lock_irq(q->queue_lock); |
e2d74ac0 | 3670 | |
d9ff4187 | 3671 | if (cfqd->active_queue) |
812df48d | 3672 | __cfq_slice_expired(cfqd, cfqd->active_queue, 0, false); |
e2d74ac0 JA |
3673 | |
3674 | while (!list_empty(&cfqd->cic_list)) { | |
d9ff4187 AV |
3675 | struct cfq_io_context *cic = list_entry(cfqd->cic_list.next, |
3676 | struct cfq_io_context, | |
3677 | queue_list); | |
89850f7e JA |
3678 | |
3679 | __cfq_exit_single_io_context(cfqd, cic); | |
d9ff4187 | 3680 | } |
e2d74ac0 | 3681 | |
c2dea2d1 | 3682 | cfq_put_async_queues(cfqd); |
b1c35769 VG |
3683 | cfq_release_cfq_groups(cfqd); |
3684 | blkiocg_del_blkio_group(&cfqd->root_group.blkg); | |
15c31be4 | 3685 | |
d9ff4187 | 3686 | spin_unlock_irq(q->queue_lock); |
a90d742e AV |
3687 | |
3688 | cfq_shutdown_timer_wq(cfqd); | |
3689 | ||
b1c35769 | 3690 | /* Wait for cfqg->blkg->key accessors to exit their grace periods. */ |
bb729bc9 | 3691 | call_rcu(&cfqd->rcu, cfq_cfqd_free); |
1da177e4 LT |
3692 | } |
3693 | ||
165125e1 | 3694 | static void *cfq_init_queue(struct request_queue *q) |
1da177e4 LT |
3695 | { |
3696 | struct cfq_data *cfqd; | |
718eee05 | 3697 | int i, j; |
cdb16e8f | 3698 | struct cfq_group *cfqg; |
615f0259 | 3699 | struct cfq_rb_root *st; |
1da177e4 | 3700 | |
94f6030c | 3701 | cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL | __GFP_ZERO, q->node); |
1da177e4 | 3702 | if (!cfqd) |
bc1c1169 | 3703 | return NULL; |
1da177e4 | 3704 | |
1fa8f6d6 VG |
3705 | /* Init root service tree */ |
3706 | cfqd->grp_service_tree = CFQ_RB_ROOT; | |
3707 | ||
cdb16e8f VG |
3708 | /* Init root group */ |
3709 | cfqg = &cfqd->root_group; | |
615f0259 VG |
3710 | for_each_cfqg_st(cfqg, i, j, st) |
3711 | *st = CFQ_RB_ROOT; | |
1fa8f6d6 | 3712 | RB_CLEAR_NODE(&cfqg->rb_node); |
26a2ac00 | 3713 | |
25bc6b07 VG |
3714 | /* Give preference to root group over other groups */ |
3715 | cfqg->weight = 2*BLKIO_WEIGHT_DEFAULT; | |
3716 | ||
25fb5169 | 3717 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
b1c35769 VG |
3718 | /* |
3719 | * Take a reference to root group which we never drop. This is just | |
3720 | * to make sure that cfq_put_cfqg() does not try to kfree root group | |
3721 | */ | |
3722 | atomic_set(&cfqg->ref, 1); | |
22084190 VG |
3723 | blkiocg_add_blkio_group(&blkio_root_cgroup, &cfqg->blkg, (void *)cfqd, |
3724 | 0); | |
25fb5169 | 3725 | #endif |
26a2ac00 JA |
3726 | /* |
3727 | * Not strictly needed (since RB_ROOT just clears the node and we | |
3728 | * zeroed cfqd on alloc), but better be safe in case someone decides | |
3729 | * to add magic to the rb code | |
3730 | */ | |
3731 | for (i = 0; i < CFQ_PRIO_LISTS; i++) | |
3732 | cfqd->prio_trees[i] = RB_ROOT; | |
3733 | ||
6118b70b JA |
3734 | /* |
3735 | * Our fallback cfqq if cfq_find_alloc_queue() runs into OOM issues. | |
3736 | * Grab a permanent reference to it, so that the normal code flow | |
3737 | * will not attempt to free it. | |
3738 | */ | |
3739 | cfq_init_cfqq(cfqd, &cfqd->oom_cfqq, 1, 0); | |
3740 | atomic_inc(&cfqd->oom_cfqq.ref); | |
cdb16e8f | 3741 | cfq_link_cfqq_cfqg(&cfqd->oom_cfqq, &cfqd->root_group); |
6118b70b | 3742 | |
d9ff4187 | 3743 | INIT_LIST_HEAD(&cfqd->cic_list); |
1da177e4 | 3744 | |
1da177e4 | 3745 | cfqd->queue = q; |
1da177e4 | 3746 | |
22e2c507 JA |
3747 | init_timer(&cfqd->idle_slice_timer); |
3748 | cfqd->idle_slice_timer.function = cfq_idle_slice_timer; | |
3749 | cfqd->idle_slice_timer.data = (unsigned long) cfqd; | |
3750 | ||
23e018a1 | 3751 | INIT_WORK(&cfqd->unplug_work, cfq_kick_queue); |
22e2c507 | 3752 | |
1da177e4 | 3753 | cfqd->cfq_quantum = cfq_quantum; |
22e2c507 JA |
3754 | cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; |
3755 | cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; | |
1da177e4 LT |
3756 | cfqd->cfq_back_max = cfq_back_max; |
3757 | cfqd->cfq_back_penalty = cfq_back_penalty; | |
22e2c507 JA |
3758 | cfqd->cfq_slice[0] = cfq_slice_async; |
3759 | cfqd->cfq_slice[1] = cfq_slice_sync; | |
3760 | cfqd->cfq_slice_async_rq = cfq_slice_async_rq; | |
3761 | cfqd->cfq_slice_idle = cfq_slice_idle; | |
963b72fc | 3762 | cfqd->cfq_latency = 1; |
ae30c286 | 3763 | cfqd->cfq_group_isolation = 0; |
e459dd08 | 3764 | cfqd->hw_tag = -1; |
edc71131 CZ |
3765 | /* |
3766 | * we optimistically start assuming sync ops weren't delayed in last | |
3767 | * second, in order to have larger depth for async operations. | |
3768 | */ | |
573412b2 | 3769 | cfqd->last_delayed_sync = jiffies - HZ; |
bb729bc9 | 3770 | INIT_RCU_HEAD(&cfqd->rcu); |
bc1c1169 | 3771 | return cfqd; |
1da177e4 LT |
3772 | } |
3773 | ||
3774 | static void cfq_slab_kill(void) | |
3775 | { | |
d6de8be7 JA |
3776 | /* |
3777 | * Caller already ensured that pending RCU callbacks are completed, | |
3778 | * so we should have no busy allocations at this point. | |
3779 | */ | |
1da177e4 LT |
3780 | if (cfq_pool) |
3781 | kmem_cache_destroy(cfq_pool); | |
3782 | if (cfq_ioc_pool) | |
3783 | kmem_cache_destroy(cfq_ioc_pool); | |
3784 | } | |
3785 | ||
3786 | static int __init cfq_slab_setup(void) | |
3787 | { | |
0a31bd5f | 3788 | cfq_pool = KMEM_CACHE(cfq_queue, 0); |
1da177e4 LT |
3789 | if (!cfq_pool) |
3790 | goto fail; | |
3791 | ||
34e6bbf2 | 3792 | cfq_ioc_pool = KMEM_CACHE(cfq_io_context, 0); |
1da177e4 LT |
3793 | if (!cfq_ioc_pool) |
3794 | goto fail; | |
3795 | ||
3796 | return 0; | |
3797 | fail: | |
3798 | cfq_slab_kill(); | |
3799 | return -ENOMEM; | |
3800 | } | |
3801 | ||
1da177e4 LT |
3802 | /* |
3803 | * sysfs parts below --> | |
3804 | */ | |
1da177e4 LT |
3805 | static ssize_t |
3806 | cfq_var_show(unsigned int var, char *page) | |
3807 | { | |
3808 | return sprintf(page, "%d\n", var); | |
3809 | } | |
3810 | ||
3811 | static ssize_t | |
3812 | cfq_var_store(unsigned int *var, const char *page, size_t count) | |
3813 | { | |
3814 | char *p = (char *) page; | |
3815 | ||
3816 | *var = simple_strtoul(p, &p, 10); | |
3817 | return count; | |
3818 | } | |
3819 | ||
1da177e4 | 3820 | #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ |
b374d18a | 3821 | static ssize_t __FUNC(struct elevator_queue *e, char *page) \ |
1da177e4 | 3822 | { \ |
3d1ab40f | 3823 | struct cfq_data *cfqd = e->elevator_data; \ |
1da177e4 LT |
3824 | unsigned int __data = __VAR; \ |
3825 | if (__CONV) \ | |
3826 | __data = jiffies_to_msecs(__data); \ | |
3827 | return cfq_var_show(__data, (page)); \ | |
3828 | } | |
3829 | SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); | |
22e2c507 JA |
3830 | SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1); |
3831 | SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1); | |
e572ec7e AV |
3832 | SHOW_FUNCTION(cfq_back_seek_max_show, cfqd->cfq_back_max, 0); |
3833 | SHOW_FUNCTION(cfq_back_seek_penalty_show, cfqd->cfq_back_penalty, 0); | |
22e2c507 JA |
3834 | SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1); |
3835 | SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1); | |
3836 | SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1); | |
3837 | SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0); | |
963b72fc | 3838 | SHOW_FUNCTION(cfq_low_latency_show, cfqd->cfq_latency, 0); |
ae30c286 | 3839 | SHOW_FUNCTION(cfq_group_isolation_show, cfqd->cfq_group_isolation, 0); |
1da177e4 LT |
3840 | #undef SHOW_FUNCTION |
3841 | ||
3842 | #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ | |
b374d18a | 3843 | static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \ |
1da177e4 | 3844 | { \ |
3d1ab40f | 3845 | struct cfq_data *cfqd = e->elevator_data; \ |
1da177e4 LT |
3846 | unsigned int __data; \ |
3847 | int ret = cfq_var_store(&__data, (page), count); \ | |
3848 | if (__data < (MIN)) \ | |
3849 | __data = (MIN); \ | |
3850 | else if (__data > (MAX)) \ | |
3851 | __data = (MAX); \ | |
3852 | if (__CONV) \ | |
3853 | *(__PTR) = msecs_to_jiffies(__data); \ | |
3854 | else \ | |
3855 | *(__PTR) = __data; \ | |
3856 | return ret; \ | |
3857 | } | |
3858 | STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); | |
fe094d98 JA |
3859 | STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, |
3860 | UINT_MAX, 1); | |
3861 | STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, | |
3862 | UINT_MAX, 1); | |
e572ec7e | 3863 | STORE_FUNCTION(cfq_back_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); |
fe094d98 JA |
3864 | STORE_FUNCTION(cfq_back_seek_penalty_store, &cfqd->cfq_back_penalty, 1, |
3865 | UINT_MAX, 0); | |
22e2c507 JA |
3866 | STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1); |
3867 | STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1); | |
3868 | STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1); | |
fe094d98 JA |
3869 | STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, |
3870 | UINT_MAX, 0); | |
963b72fc | 3871 | STORE_FUNCTION(cfq_low_latency_store, &cfqd->cfq_latency, 0, 1, 0); |
ae30c286 | 3872 | STORE_FUNCTION(cfq_group_isolation_store, &cfqd->cfq_group_isolation, 0, 1, 0); |
1da177e4 LT |
3873 | #undef STORE_FUNCTION |
3874 | ||
e572ec7e AV |
3875 | #define CFQ_ATTR(name) \ |
3876 | __ATTR(name, S_IRUGO|S_IWUSR, cfq_##name##_show, cfq_##name##_store) | |
3877 | ||
3878 | static struct elv_fs_entry cfq_attrs[] = { | |
3879 | CFQ_ATTR(quantum), | |
e572ec7e AV |
3880 | CFQ_ATTR(fifo_expire_sync), |
3881 | CFQ_ATTR(fifo_expire_async), | |
3882 | CFQ_ATTR(back_seek_max), | |
3883 | CFQ_ATTR(back_seek_penalty), | |
3884 | CFQ_ATTR(slice_sync), | |
3885 | CFQ_ATTR(slice_async), | |
3886 | CFQ_ATTR(slice_async_rq), | |
3887 | CFQ_ATTR(slice_idle), | |
963b72fc | 3888 | CFQ_ATTR(low_latency), |
ae30c286 | 3889 | CFQ_ATTR(group_isolation), |
e572ec7e | 3890 | __ATTR_NULL |
1da177e4 LT |
3891 | }; |
3892 | ||
1da177e4 LT |
3893 | static struct elevator_type iosched_cfq = { |
3894 | .ops = { | |
3895 | .elevator_merge_fn = cfq_merge, | |
3896 | .elevator_merged_fn = cfq_merged_request, | |
3897 | .elevator_merge_req_fn = cfq_merged_requests, | |
da775265 | 3898 | .elevator_allow_merge_fn = cfq_allow_merge, |
812d4026 | 3899 | .elevator_bio_merged_fn = cfq_bio_merged, |
b4878f24 | 3900 | .elevator_dispatch_fn = cfq_dispatch_requests, |
1da177e4 | 3901 | .elevator_add_req_fn = cfq_insert_request, |
b4878f24 | 3902 | .elevator_activate_req_fn = cfq_activate_request, |
1da177e4 LT |
3903 | .elevator_deactivate_req_fn = cfq_deactivate_request, |
3904 | .elevator_queue_empty_fn = cfq_queue_empty, | |
3905 | .elevator_completed_req_fn = cfq_completed_request, | |
21183b07 JA |
3906 | .elevator_former_req_fn = elv_rb_former_request, |
3907 | .elevator_latter_req_fn = elv_rb_latter_request, | |
1da177e4 LT |
3908 | .elevator_set_req_fn = cfq_set_request, |
3909 | .elevator_put_req_fn = cfq_put_request, | |
3910 | .elevator_may_queue_fn = cfq_may_queue, | |
3911 | .elevator_init_fn = cfq_init_queue, | |
3912 | .elevator_exit_fn = cfq_exit_queue, | |
fc46379d | 3913 | .trim = cfq_free_io_context, |
1da177e4 | 3914 | }, |
3d1ab40f | 3915 | .elevator_attrs = cfq_attrs, |
1da177e4 LT |
3916 | .elevator_name = "cfq", |
3917 | .elevator_owner = THIS_MODULE, | |
3918 | }; | |
3919 | ||
3e252066 VG |
3920 | #ifdef CONFIG_CFQ_GROUP_IOSCHED |
3921 | static struct blkio_policy_type blkio_policy_cfq = { | |
3922 | .ops = { | |
3923 | .blkio_unlink_group_fn = cfq_unlink_blkio_group, | |
3924 | .blkio_update_group_weight_fn = cfq_update_blkio_group_weight, | |
3925 | }, | |
3926 | }; | |
3927 | #else | |
3928 | static struct blkio_policy_type blkio_policy_cfq; | |
3929 | #endif | |
3930 | ||
1da177e4 LT |
3931 | static int __init cfq_init(void) |
3932 | { | |
22e2c507 JA |
3933 | /* |
3934 | * could be 0 on HZ < 1000 setups | |
3935 | */ | |
3936 | if (!cfq_slice_async) | |
3937 | cfq_slice_async = 1; | |
3938 | if (!cfq_slice_idle) | |
3939 | cfq_slice_idle = 1; | |
3940 | ||
1da177e4 LT |
3941 | if (cfq_slab_setup()) |
3942 | return -ENOMEM; | |
3943 | ||
2fdd82bd | 3944 | elv_register(&iosched_cfq); |
3e252066 | 3945 | blkio_policy_register(&blkio_policy_cfq); |
1da177e4 | 3946 | |
2fdd82bd | 3947 | return 0; |
1da177e4 LT |
3948 | } |
3949 | ||
3950 | static void __exit cfq_exit(void) | |
3951 | { | |
6e9a4738 | 3952 | DECLARE_COMPLETION_ONSTACK(all_gone); |
3e252066 | 3953 | blkio_policy_unregister(&blkio_policy_cfq); |
1da177e4 | 3954 | elv_unregister(&iosched_cfq); |
334e94de | 3955 | ioc_gone = &all_gone; |
fba82272 OH |
3956 | /* ioc_gone's update must be visible before reading ioc_count */ |
3957 | smp_wmb(); | |
d6de8be7 JA |
3958 | |
3959 | /* | |
3960 | * this also protects us from entering cfq_slab_kill() with | |
3961 | * pending RCU callbacks | |
3962 | */ | |
245b2e70 | 3963 | if (elv_ioc_count_read(cfq_ioc_count)) |
9a11b4ed | 3964 | wait_for_completion(&all_gone); |
83521d3e | 3965 | cfq_slab_kill(); |
1da177e4 LT |
3966 | } |
3967 | ||
3968 | module_init(cfq_init); | |
3969 | module_exit(cfq_exit); | |
3970 | ||
3971 | MODULE_AUTHOR("Jens Axboe"); | |
3972 | MODULE_LICENSE("GPL"); | |
3973 | MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler"); |