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7caa4715 TH |
1 | /* SPDX-License-Identifier: GPL-2.0 |
2 | * | |
3 | * IO cost model based controller. | |
4 | * | |
5 | * Copyright (C) 2019 Tejun Heo <tj@kernel.org> | |
6 | * Copyright (C) 2019 Andy Newell <newella@fb.com> | |
7 | * Copyright (C) 2019 Facebook | |
8 | * | |
9 | * One challenge of controlling IO resources is the lack of trivially | |
10 | * observable cost metric. This is distinguished from CPU and memory where | |
11 | * wallclock time and the number of bytes can serve as accurate enough | |
12 | * approximations. | |
13 | * | |
14 | * Bandwidth and iops are the most commonly used metrics for IO devices but | |
15 | * depending on the type and specifics of the device, different IO patterns | |
16 | * easily lead to multiple orders of magnitude variations rendering them | |
17 | * useless for the purpose of IO capacity distribution. While on-device | |
18 | * time, with a lot of clutches, could serve as a useful approximation for | |
19 | * non-queued rotational devices, this is no longer viable with modern | |
20 | * devices, even the rotational ones. | |
21 | * | |
22 | * While there is no cost metric we can trivially observe, it isn't a | |
23 | * complete mystery. For example, on a rotational device, seek cost | |
24 | * dominates while a contiguous transfer contributes a smaller amount | |
25 | * proportional to the size. If we can characterize at least the relative | |
26 | * costs of these different types of IOs, it should be possible to | |
27 | * implement a reasonable work-conserving proportional IO resource | |
28 | * distribution. | |
29 | * | |
30 | * 1. IO Cost Model | |
31 | * | |
32 | * IO cost model estimates the cost of an IO given its basic parameters and | |
33 | * history (e.g. the end sector of the last IO). The cost is measured in | |
34 | * device time. If a given IO is estimated to cost 10ms, the device should | |
35 | * be able to process ~100 of those IOs in a second. | |
36 | * | |
37 | * Currently, there's only one builtin cost model - linear. Each IO is | |
38 | * classified as sequential or random and given a base cost accordingly. | |
39 | * On top of that, a size cost proportional to the length of the IO is | |
40 | * added. While simple, this model captures the operational | |
41 | * characteristics of a wide varienty of devices well enough. Default | |
42 | * paramters for several different classes of devices are provided and the | |
43 | * parameters can be configured from userspace via | |
44 | * /sys/fs/cgroup/io.cost.model. | |
45 | * | |
46 | * If needed, tools/cgroup/iocost_coef_gen.py can be used to generate | |
47 | * device-specific coefficients. | |
48 | * | |
49 | * 2. Control Strategy | |
50 | * | |
51 | * The device virtual time (vtime) is used as the primary control metric. | |
52 | * The control strategy is composed of the following three parts. | |
53 | * | |
54 | * 2-1. Vtime Distribution | |
55 | * | |
56 | * When a cgroup becomes active in terms of IOs, its hierarchical share is | |
57 | * calculated. Please consider the following hierarchy where the numbers | |
58 | * inside parentheses denote the configured weights. | |
59 | * | |
60 | * root | |
61 | * / \ | |
62 | * A (w:100) B (w:300) | |
63 | * / \ | |
64 | * A0 (w:100) A1 (w:100) | |
65 | * | |
66 | * If B is idle and only A0 and A1 are actively issuing IOs, as the two are | |
67 | * of equal weight, each gets 50% share. If then B starts issuing IOs, B | |
68 | * gets 300/(100+300) or 75% share, and A0 and A1 equally splits the rest, | |
69 | * 12.5% each. The distribution mechanism only cares about these flattened | |
70 | * shares. They're called hweights (hierarchical weights) and always add | |
71 | * upto 1 (HWEIGHT_WHOLE). | |
72 | * | |
73 | * A given cgroup's vtime runs slower in inverse proportion to its hweight. | |
74 | * For example, with 12.5% weight, A0's time runs 8 times slower (100/12.5) | |
75 | * against the device vtime - an IO which takes 10ms on the underlying | |
76 | * device is considered to take 80ms on A0. | |
77 | * | |
78 | * This constitutes the basis of IO capacity distribution. Each cgroup's | |
79 | * vtime is running at a rate determined by its hweight. A cgroup tracks | |
80 | * the vtime consumed by past IOs and can issue a new IO iff doing so | |
81 | * wouldn't outrun the current device vtime. Otherwise, the IO is | |
82 | * suspended until the vtime has progressed enough to cover it. | |
83 | * | |
84 | * 2-2. Vrate Adjustment | |
85 | * | |
86 | * It's unrealistic to expect the cost model to be perfect. There are too | |
87 | * many devices and even on the same device the overall performance | |
88 | * fluctuates depending on numerous factors such as IO mixture and device | |
89 | * internal garbage collection. The controller needs to adapt dynamically. | |
90 | * | |
91 | * This is achieved by adjusting the overall IO rate according to how busy | |
92 | * the device is. If the device becomes overloaded, we're sending down too | |
93 | * many IOs and should generally slow down. If there are waiting issuers | |
94 | * but the device isn't saturated, we're issuing too few and should | |
95 | * generally speed up. | |
96 | * | |
97 | * To slow down, we lower the vrate - the rate at which the device vtime | |
98 | * passes compared to the wall clock. For example, if the vtime is running | |
99 | * at the vrate of 75%, all cgroups added up would only be able to issue | |
100 | * 750ms worth of IOs per second, and vice-versa for speeding up. | |
101 | * | |
102 | * Device business is determined using two criteria - rq wait and | |
103 | * completion latencies. | |
104 | * | |
105 | * When a device gets saturated, the on-device and then the request queues | |
106 | * fill up and a bio which is ready to be issued has to wait for a request | |
107 | * to become available. When this delay becomes noticeable, it's a clear | |
108 | * indication that the device is saturated and we lower the vrate. This | |
109 | * saturation signal is fairly conservative as it only triggers when both | |
110 | * hardware and software queues are filled up, and is used as the default | |
111 | * busy signal. | |
112 | * | |
113 | * As devices can have deep queues and be unfair in how the queued commands | |
114 | * are executed, soley depending on rq wait may not result in satisfactory | |
115 | * control quality. For a better control quality, completion latency QoS | |
116 | * parameters can be configured so that the device is considered saturated | |
117 | * if N'th percentile completion latency rises above the set point. | |
118 | * | |
119 | * The completion latency requirements are a function of both the | |
120 | * underlying device characteristics and the desired IO latency quality of | |
121 | * service. There is an inherent trade-off - the tighter the latency QoS, | |
122 | * the higher the bandwidth lossage. Latency QoS is disabled by default | |
123 | * and can be set through /sys/fs/cgroup/io.cost.qos. | |
124 | * | |
125 | * 2-3. Work Conservation | |
126 | * | |
127 | * Imagine two cgroups A and B with equal weights. A is issuing a small IO | |
128 | * periodically while B is sending out enough parallel IOs to saturate the | |
129 | * device on its own. Let's say A's usage amounts to 100ms worth of IO | |
130 | * cost per second, i.e., 10% of the device capacity. The naive | |
131 | * distribution of half and half would lead to 60% utilization of the | |
132 | * device, a significant reduction in the total amount of work done | |
133 | * compared to free-for-all competition. This is too high a cost to pay | |
134 | * for IO control. | |
135 | * | |
136 | * To conserve the total amount of work done, we keep track of how much | |
137 | * each active cgroup is actually using and yield part of its weight if | |
138 | * there are other cgroups which can make use of it. In the above case, | |
139 | * A's weight will be lowered so that it hovers above the actual usage and | |
140 | * B would be able to use the rest. | |
141 | * | |
142 | * As we don't want to penalize a cgroup for donating its weight, the | |
143 | * surplus weight adjustment factors in a margin and has an immediate | |
144 | * snapback mechanism in case the cgroup needs more IO vtime for itself. | |
145 | * | |
146 | * Note that adjusting down surplus weights has the same effects as | |
147 | * accelerating vtime for other cgroups and work conservation can also be | |
148 | * implemented by adjusting vrate dynamically. However, squaring who can | |
149 | * donate and should take back how much requires hweight propagations | |
150 | * anyway making it easier to implement and understand as a separate | |
151 | * mechanism. | |
6954ff18 TH |
152 | * |
153 | * 3. Monitoring | |
154 | * | |
155 | * Instead of debugfs or other clumsy monitoring mechanisms, this | |
156 | * controller uses a drgn based monitoring script - | |
157 | * tools/cgroup/iocost_monitor.py. For details on drgn, please see | |
158 | * https://github.com/osandov/drgn. The ouput looks like the following. | |
159 | * | |
160 | * sdb RUN per=300ms cur_per=234.218:v203.695 busy= +1 vrate= 62.12% | |
161 | * active weight hweight% inflt% del_ms usages% | |
162 | * test/a * 50/ 50 33.33/ 33.33 27.65 0*041 033:033:033 | |
163 | * test/b * 100/ 100 66.67/ 66.67 17.56 0*000 066:079:077 | |
164 | * | |
165 | * - per : Timer period | |
166 | * - cur_per : Internal wall and device vtime clock | |
167 | * - vrate : Device virtual time rate against wall clock | |
168 | * - weight : Surplus-adjusted and configured weights | |
169 | * - hweight : Surplus-adjusted and configured hierarchical weights | |
170 | * - inflt : The percentage of in-flight IO cost at the end of last period | |
171 | * - del_ms : Deferred issuer delay induction level and duration | |
172 | * - usages : Usage history | |
7caa4715 TH |
173 | */ |
174 | ||
175 | #include <linux/kernel.h> | |
176 | #include <linux/module.h> | |
177 | #include <linux/timer.h> | |
178 | #include <linux/time64.h> | |
179 | #include <linux/parser.h> | |
180 | #include <linux/sched/signal.h> | |
181 | #include <linux/blk-cgroup.h> | |
182 | #include "blk-rq-qos.h" | |
183 | #include "blk-stat.h" | |
184 | #include "blk-wbt.h" | |
185 | ||
186 | #ifdef CONFIG_TRACEPOINTS | |
187 | ||
188 | /* copied from TRACE_CGROUP_PATH, see cgroup-internal.h */ | |
189 | #define TRACE_IOCG_PATH_LEN 1024 | |
190 | static DEFINE_SPINLOCK(trace_iocg_path_lock); | |
191 | static char trace_iocg_path[TRACE_IOCG_PATH_LEN]; | |
192 | ||
193 | #define TRACE_IOCG_PATH(type, iocg, ...) \ | |
194 | do { \ | |
195 | unsigned long flags; \ | |
196 | if (trace_iocost_##type##_enabled()) { \ | |
197 | spin_lock_irqsave(&trace_iocg_path_lock, flags); \ | |
198 | cgroup_path(iocg_to_blkg(iocg)->blkcg->css.cgroup, \ | |
199 | trace_iocg_path, TRACE_IOCG_PATH_LEN); \ | |
200 | trace_iocost_##type(iocg, trace_iocg_path, \ | |
201 | ##__VA_ARGS__); \ | |
202 | spin_unlock_irqrestore(&trace_iocg_path_lock, flags); \ | |
203 | } \ | |
204 | } while (0) | |
205 | ||
206 | #else /* CONFIG_TRACE_POINTS */ | |
207 | #define TRACE_IOCG_PATH(type, iocg, ...) do { } while (0) | |
208 | #endif /* CONFIG_TRACE_POINTS */ | |
209 | ||
210 | enum { | |
211 | MILLION = 1000000, | |
212 | ||
213 | /* timer period is calculated from latency requirements, bound it */ | |
214 | MIN_PERIOD = USEC_PER_MSEC, | |
215 | MAX_PERIOD = USEC_PER_SEC, | |
216 | ||
217 | /* | |
218 | * A cgroup's vtime can run 50% behind the device vtime, which | |
219 | * serves as its IO credit buffer. Surplus weight adjustment is | |
220 | * immediately canceled if the vtime margin runs below 10%. | |
221 | */ | |
222 | MARGIN_PCT = 50, | |
223 | INUSE_MARGIN_PCT = 10, | |
224 | ||
225 | /* Have some play in waitq timer operations */ | |
226 | WAITQ_TIMER_MARGIN_PCT = 5, | |
227 | ||
228 | /* | |
229 | * vtime can wrap well within a reasonable uptime when vrate is | |
230 | * consistently raised. Don't trust recorded cgroup vtime if the | |
231 | * period counter indicates that it's older than 5mins. | |
232 | */ | |
233 | VTIME_VALID_DUR = 300 * USEC_PER_SEC, | |
234 | ||
235 | /* | |
236 | * Remember the past three non-zero usages and use the max for | |
237 | * surplus calculation. Three slots guarantee that we remember one | |
238 | * full period usage from the last active stretch even after | |
239 | * partial deactivation and re-activation periods. Don't start | |
240 | * giving away weight before collecting two data points to prevent | |
241 | * hweight adjustments based on one partial activation period. | |
242 | */ | |
243 | NR_USAGE_SLOTS = 3, | |
244 | MIN_VALID_USAGES = 2, | |
245 | ||
246 | /* 1/64k is granular enough and can easily be handled w/ u32 */ | |
247 | HWEIGHT_WHOLE = 1 << 16, | |
248 | ||
249 | /* | |
250 | * As vtime is used to calculate the cost of each IO, it needs to | |
251 | * be fairly high precision. For example, it should be able to | |
252 | * represent the cost of a single page worth of discard with | |
253 | * suffificient accuracy. At the same time, it should be able to | |
254 | * represent reasonably long enough durations to be useful and | |
255 | * convenient during operation. | |
256 | * | |
257 | * 1s worth of vtime is 2^37. This gives us both sub-nanosecond | |
258 | * granularity and days of wrap-around time even at extreme vrates. | |
259 | */ | |
260 | VTIME_PER_SEC_SHIFT = 37, | |
261 | VTIME_PER_SEC = 1LLU << VTIME_PER_SEC_SHIFT, | |
262 | VTIME_PER_USEC = VTIME_PER_SEC / USEC_PER_SEC, | |
263 | ||
264 | /* bound vrate adjustments within two orders of magnitude */ | |
265 | VRATE_MIN_PPM = 10000, /* 1% */ | |
266 | VRATE_MAX_PPM = 100000000, /* 10000% */ | |
267 | ||
268 | VRATE_MIN = VTIME_PER_USEC * VRATE_MIN_PPM / MILLION, | |
269 | VRATE_CLAMP_ADJ_PCT = 4, | |
270 | ||
271 | /* if IOs end up waiting for requests, issue less */ | |
272 | RQ_WAIT_BUSY_PCT = 5, | |
273 | ||
274 | /* unbusy hysterisis */ | |
275 | UNBUSY_THR_PCT = 75, | |
276 | ||
277 | /* don't let cmds which take a very long time pin lagging for too long */ | |
278 | MAX_LAGGING_PERIODS = 10, | |
279 | ||
280 | /* | |
281 | * If usage% * 1.25 + 2% is lower than hweight% by more than 3%, | |
282 | * donate the surplus. | |
283 | */ | |
284 | SURPLUS_SCALE_PCT = 125, /* * 125% */ | |
285 | SURPLUS_SCALE_ABS = HWEIGHT_WHOLE / 50, /* + 2% */ | |
286 | SURPLUS_MIN_ADJ_DELTA = HWEIGHT_WHOLE / 33, /* 3% */ | |
287 | ||
288 | /* switch iff the conditions are met for longer than this */ | |
289 | AUTOP_CYCLE_NSEC = 10LLU * NSEC_PER_SEC, | |
290 | ||
291 | /* | |
292 | * Count IO size in 4k pages. The 12bit shift helps keeping | |
293 | * size-proportional components of cost calculation in closer | |
294 | * numbers of digits to per-IO cost components. | |
295 | */ | |
296 | IOC_PAGE_SHIFT = 12, | |
297 | IOC_PAGE_SIZE = 1 << IOC_PAGE_SHIFT, | |
298 | IOC_SECT_TO_PAGE_SHIFT = IOC_PAGE_SHIFT - SECTOR_SHIFT, | |
299 | ||
300 | /* if apart further than 16M, consider randio for linear model */ | |
301 | LCOEF_RANDIO_PAGES = 4096, | |
302 | }; | |
303 | ||
304 | enum ioc_running { | |
305 | IOC_IDLE, | |
306 | IOC_RUNNING, | |
307 | IOC_STOP, | |
308 | }; | |
309 | ||
310 | /* io.cost.qos controls including per-dev enable of the whole controller */ | |
311 | enum { | |
312 | QOS_ENABLE, | |
313 | QOS_CTRL, | |
314 | NR_QOS_CTRL_PARAMS, | |
315 | }; | |
316 | ||
317 | /* io.cost.qos params */ | |
318 | enum { | |
319 | QOS_RPPM, | |
320 | QOS_RLAT, | |
321 | QOS_WPPM, | |
322 | QOS_WLAT, | |
323 | QOS_MIN, | |
324 | QOS_MAX, | |
325 | NR_QOS_PARAMS, | |
326 | }; | |
327 | ||
328 | /* io.cost.model controls */ | |
329 | enum { | |
330 | COST_CTRL, | |
331 | COST_MODEL, | |
332 | NR_COST_CTRL_PARAMS, | |
333 | }; | |
334 | ||
335 | /* builtin linear cost model coefficients */ | |
336 | enum { | |
337 | I_LCOEF_RBPS, | |
338 | I_LCOEF_RSEQIOPS, | |
339 | I_LCOEF_RRANDIOPS, | |
340 | I_LCOEF_WBPS, | |
341 | I_LCOEF_WSEQIOPS, | |
342 | I_LCOEF_WRANDIOPS, | |
343 | NR_I_LCOEFS, | |
344 | }; | |
345 | ||
346 | enum { | |
347 | LCOEF_RPAGE, | |
348 | LCOEF_RSEQIO, | |
349 | LCOEF_RRANDIO, | |
350 | LCOEF_WPAGE, | |
351 | LCOEF_WSEQIO, | |
352 | LCOEF_WRANDIO, | |
353 | NR_LCOEFS, | |
354 | }; | |
355 | ||
356 | enum { | |
357 | AUTOP_INVALID, | |
358 | AUTOP_HDD, | |
359 | AUTOP_SSD_QD1, | |
360 | AUTOP_SSD_DFL, | |
361 | AUTOP_SSD_FAST, | |
362 | }; | |
363 | ||
364 | struct ioc_gq; | |
365 | ||
366 | struct ioc_params { | |
367 | u32 qos[NR_QOS_PARAMS]; | |
368 | u64 i_lcoefs[NR_I_LCOEFS]; | |
369 | u64 lcoefs[NR_LCOEFS]; | |
370 | u32 too_fast_vrate_pct; | |
371 | u32 too_slow_vrate_pct; | |
372 | }; | |
373 | ||
374 | struct ioc_missed { | |
375 | u32 nr_met; | |
376 | u32 nr_missed; | |
377 | u32 last_met; | |
378 | u32 last_missed; | |
379 | }; | |
380 | ||
381 | struct ioc_pcpu_stat { | |
382 | struct ioc_missed missed[2]; | |
383 | ||
384 | u64 rq_wait_ns; | |
385 | u64 last_rq_wait_ns; | |
386 | }; | |
387 | ||
388 | /* per device */ | |
389 | struct ioc { | |
390 | struct rq_qos rqos; | |
391 | ||
392 | bool enabled; | |
393 | ||
394 | struct ioc_params params; | |
395 | u32 period_us; | |
396 | u32 margin_us; | |
397 | u64 vrate_min; | |
398 | u64 vrate_max; | |
399 | ||
400 | spinlock_t lock; | |
401 | struct timer_list timer; | |
402 | struct list_head active_iocgs; /* active cgroups */ | |
403 | struct ioc_pcpu_stat __percpu *pcpu_stat; | |
404 | ||
405 | enum ioc_running running; | |
406 | atomic64_t vtime_rate; | |
407 | ||
408 | seqcount_t period_seqcount; | |
409 | u32 period_at; /* wallclock starttime */ | |
410 | u64 period_at_vtime; /* vtime starttime */ | |
411 | ||
412 | atomic64_t cur_period; /* inc'd each period */ | |
413 | int busy_level; /* saturation history */ | |
414 | ||
415 | u64 inuse_margin_vtime; | |
416 | bool weights_updated; | |
417 | atomic_t hweight_gen; /* for lazy hweights */ | |
418 | ||
419 | u64 autop_too_fast_at; | |
420 | u64 autop_too_slow_at; | |
421 | int autop_idx; | |
422 | bool user_qos_params:1; | |
423 | bool user_cost_model:1; | |
424 | }; | |
425 | ||
426 | /* per device-cgroup pair */ | |
427 | struct ioc_gq { | |
428 | struct blkg_policy_data pd; | |
429 | struct ioc *ioc; | |
430 | ||
431 | /* | |
432 | * A iocg can get its weight from two sources - an explicit | |
433 | * per-device-cgroup configuration or the default weight of the | |
434 | * cgroup. `cfg_weight` is the explicit per-device-cgroup | |
435 | * configuration. `weight` is the effective considering both | |
436 | * sources. | |
437 | * | |
438 | * When an idle cgroup becomes active its `active` goes from 0 to | |
439 | * `weight`. `inuse` is the surplus adjusted active weight. | |
440 | * `active` and `inuse` are used to calculate `hweight_active` and | |
441 | * `hweight_inuse`. | |
442 | * | |
443 | * `last_inuse` remembers `inuse` while an iocg is idle to persist | |
444 | * surplus adjustments. | |
445 | */ | |
446 | u32 cfg_weight; | |
447 | u32 weight; | |
448 | u32 active; | |
449 | u32 inuse; | |
450 | u32 last_inuse; | |
451 | ||
452 | sector_t cursor; /* to detect randio */ | |
453 | ||
454 | /* | |
455 | * `vtime` is this iocg's vtime cursor which progresses as IOs are | |
456 | * issued. If lagging behind device vtime, the delta represents | |
457 | * the currently available IO budget. If runnning ahead, the | |
458 | * overage. | |
459 | * | |
460 | * `vtime_done` is the same but progressed on completion rather | |
461 | * than issue. The delta behind `vtime` represents the cost of | |
462 | * currently in-flight IOs. | |
463 | * | |
464 | * `last_vtime` is used to remember `vtime` at the end of the last | |
465 | * period to calculate utilization. | |
466 | */ | |
467 | atomic64_t vtime; | |
468 | atomic64_t done_vtime; | |
469 | u64 last_vtime; | |
470 | ||
471 | /* | |
472 | * The period this iocg was last active in. Used for deactivation | |
473 | * and invalidating `vtime`. | |
474 | */ | |
475 | atomic64_t active_period; | |
476 | struct list_head active_list; | |
477 | ||
478 | /* see __propagate_active_weight() and current_hweight() for details */ | |
479 | u64 child_active_sum; | |
480 | u64 child_inuse_sum; | |
481 | int hweight_gen; | |
482 | u32 hweight_active; | |
483 | u32 hweight_inuse; | |
484 | bool has_surplus; | |
485 | ||
486 | struct wait_queue_head waitq; | |
487 | struct hrtimer waitq_timer; | |
488 | struct hrtimer delay_timer; | |
489 | ||
490 | /* usage is recorded as fractions of HWEIGHT_WHOLE */ | |
491 | int usage_idx; | |
492 | u32 usages[NR_USAGE_SLOTS]; | |
493 | ||
494 | /* this iocg's depth in the hierarchy and ancestors including self */ | |
495 | int level; | |
496 | struct ioc_gq *ancestors[]; | |
497 | }; | |
498 | ||
499 | /* per cgroup */ | |
500 | struct ioc_cgrp { | |
501 | struct blkcg_policy_data cpd; | |
502 | unsigned int dfl_weight; | |
503 | }; | |
504 | ||
505 | struct ioc_now { | |
506 | u64 now_ns; | |
507 | u32 now; | |
508 | u64 vnow; | |
509 | u64 vrate; | |
510 | }; | |
511 | ||
512 | struct iocg_wait { | |
513 | struct wait_queue_entry wait; | |
514 | struct bio *bio; | |
515 | u64 abs_cost; | |
516 | bool committed; | |
517 | }; | |
518 | ||
519 | struct iocg_wake_ctx { | |
520 | struct ioc_gq *iocg; | |
521 | u32 hw_inuse; | |
522 | s64 vbudget; | |
523 | }; | |
524 | ||
525 | static const struct ioc_params autop[] = { | |
526 | [AUTOP_HDD] = { | |
527 | .qos = { | |
528 | [QOS_RLAT] = 50000, /* 50ms */ | |
529 | [QOS_WLAT] = 50000, | |
530 | [QOS_MIN] = VRATE_MIN_PPM, | |
531 | [QOS_MAX] = VRATE_MAX_PPM, | |
532 | }, | |
533 | .i_lcoefs = { | |
534 | [I_LCOEF_RBPS] = 174019176, | |
535 | [I_LCOEF_RSEQIOPS] = 41708, | |
536 | [I_LCOEF_RRANDIOPS] = 370, | |
537 | [I_LCOEF_WBPS] = 178075866, | |
538 | [I_LCOEF_WSEQIOPS] = 42705, | |
539 | [I_LCOEF_WRANDIOPS] = 378, | |
540 | }, | |
541 | }, | |
542 | [AUTOP_SSD_QD1] = { | |
543 | .qos = { | |
544 | [QOS_RLAT] = 25000, /* 25ms */ | |
545 | [QOS_WLAT] = 25000, | |
546 | [QOS_MIN] = VRATE_MIN_PPM, | |
547 | [QOS_MAX] = VRATE_MAX_PPM, | |
548 | }, | |
549 | .i_lcoefs = { | |
550 | [I_LCOEF_RBPS] = 245855193, | |
551 | [I_LCOEF_RSEQIOPS] = 61575, | |
552 | [I_LCOEF_RRANDIOPS] = 6946, | |
553 | [I_LCOEF_WBPS] = 141365009, | |
554 | [I_LCOEF_WSEQIOPS] = 33716, | |
555 | [I_LCOEF_WRANDIOPS] = 26796, | |
556 | }, | |
557 | }, | |
558 | [AUTOP_SSD_DFL] = { | |
559 | .qos = { | |
560 | [QOS_RLAT] = 25000, /* 25ms */ | |
561 | [QOS_WLAT] = 25000, | |
562 | [QOS_MIN] = VRATE_MIN_PPM, | |
563 | [QOS_MAX] = VRATE_MAX_PPM, | |
564 | }, | |
565 | .i_lcoefs = { | |
566 | [I_LCOEF_RBPS] = 488636629, | |
567 | [I_LCOEF_RSEQIOPS] = 8932, | |
568 | [I_LCOEF_RRANDIOPS] = 8518, | |
569 | [I_LCOEF_WBPS] = 427891549, | |
570 | [I_LCOEF_WSEQIOPS] = 28755, | |
571 | [I_LCOEF_WRANDIOPS] = 21940, | |
572 | }, | |
573 | .too_fast_vrate_pct = 500, | |
574 | }, | |
575 | [AUTOP_SSD_FAST] = { | |
576 | .qos = { | |
577 | [QOS_RLAT] = 5000, /* 5ms */ | |
578 | [QOS_WLAT] = 5000, | |
579 | [QOS_MIN] = VRATE_MIN_PPM, | |
580 | [QOS_MAX] = VRATE_MAX_PPM, | |
581 | }, | |
582 | .i_lcoefs = { | |
583 | [I_LCOEF_RBPS] = 3102524156LLU, | |
584 | [I_LCOEF_RSEQIOPS] = 724816, | |
585 | [I_LCOEF_RRANDIOPS] = 778122, | |
586 | [I_LCOEF_WBPS] = 1742780862LLU, | |
587 | [I_LCOEF_WSEQIOPS] = 425702, | |
588 | [I_LCOEF_WRANDIOPS] = 443193, | |
589 | }, | |
590 | .too_slow_vrate_pct = 10, | |
591 | }, | |
592 | }; | |
593 | ||
594 | /* | |
595 | * vrate adjust percentages indexed by ioc->busy_level. We adjust up on | |
596 | * vtime credit shortage and down on device saturation. | |
597 | */ | |
598 | static u32 vrate_adj_pct[] = | |
599 | { 0, 0, 0, 0, | |
600 | 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, | |
601 | 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, | |
602 | 4, 4, 4, 4, 4, 4, 4, 4, 8, 8, 8, 8, 8, 8, 8, 8, 16 }; | |
603 | ||
604 | static struct blkcg_policy blkcg_policy_iocost; | |
605 | ||
606 | /* accessors and helpers */ | |
607 | static struct ioc *rqos_to_ioc(struct rq_qos *rqos) | |
608 | { | |
609 | return container_of(rqos, struct ioc, rqos); | |
610 | } | |
611 | ||
612 | static struct ioc *q_to_ioc(struct request_queue *q) | |
613 | { | |
614 | return rqos_to_ioc(rq_qos_id(q, RQ_QOS_COST)); | |
615 | } | |
616 | ||
617 | static const char *q_name(struct request_queue *q) | |
618 | { | |
619 | if (test_bit(QUEUE_FLAG_REGISTERED, &q->queue_flags)) | |
620 | return kobject_name(q->kobj.parent); | |
621 | else | |
622 | return "<unknown>"; | |
623 | } | |
624 | ||
625 | static const char __maybe_unused *ioc_name(struct ioc *ioc) | |
626 | { | |
627 | return q_name(ioc->rqos.q); | |
628 | } | |
629 | ||
630 | static struct ioc_gq *pd_to_iocg(struct blkg_policy_data *pd) | |
631 | { | |
632 | return pd ? container_of(pd, struct ioc_gq, pd) : NULL; | |
633 | } | |
634 | ||
635 | static struct ioc_gq *blkg_to_iocg(struct blkcg_gq *blkg) | |
636 | { | |
637 | return pd_to_iocg(blkg_to_pd(blkg, &blkcg_policy_iocost)); | |
638 | } | |
639 | ||
640 | static struct blkcg_gq *iocg_to_blkg(struct ioc_gq *iocg) | |
641 | { | |
642 | return pd_to_blkg(&iocg->pd); | |
643 | } | |
644 | ||
645 | static struct ioc_cgrp *blkcg_to_iocc(struct blkcg *blkcg) | |
646 | { | |
647 | return container_of(blkcg_to_cpd(blkcg, &blkcg_policy_iocost), | |
648 | struct ioc_cgrp, cpd); | |
649 | } | |
650 | ||
651 | /* | |
652 | * Scale @abs_cost to the inverse of @hw_inuse. The lower the hierarchical | |
653 | * weight, the more expensive each IO. | |
654 | */ | |
655 | static u64 abs_cost_to_cost(u64 abs_cost, u32 hw_inuse) | |
656 | { | |
657 | return DIV64_U64_ROUND_UP(abs_cost * HWEIGHT_WHOLE, hw_inuse); | |
658 | } | |
659 | ||
660 | static void iocg_commit_bio(struct ioc_gq *iocg, struct bio *bio, u64 cost) | |
661 | { | |
662 | bio->bi_iocost_cost = cost; | |
663 | atomic64_add(cost, &iocg->vtime); | |
664 | } | |
665 | ||
666 | #define CREATE_TRACE_POINTS | |
667 | #include <trace/events/iocost.h> | |
668 | ||
669 | /* latency Qos params changed, update period_us and all the dependent params */ | |
670 | static void ioc_refresh_period_us(struct ioc *ioc) | |
671 | { | |
672 | u32 ppm, lat, multi, period_us; | |
673 | ||
674 | lockdep_assert_held(&ioc->lock); | |
675 | ||
676 | /* pick the higher latency target */ | |
677 | if (ioc->params.qos[QOS_RLAT] >= ioc->params.qos[QOS_WLAT]) { | |
678 | ppm = ioc->params.qos[QOS_RPPM]; | |
679 | lat = ioc->params.qos[QOS_RLAT]; | |
680 | } else { | |
681 | ppm = ioc->params.qos[QOS_WPPM]; | |
682 | lat = ioc->params.qos[QOS_WLAT]; | |
683 | } | |
684 | ||
685 | /* | |
686 | * We want the period to be long enough to contain a healthy number | |
687 | * of IOs while short enough for granular control. Define it as a | |
688 | * multiple of the latency target. Ideally, the multiplier should | |
689 | * be scaled according to the percentile so that it would nominally | |
690 | * contain a certain number of requests. Let's be simpler and | |
691 | * scale it linearly so that it's 2x >= pct(90) and 10x at pct(50). | |
692 | */ | |
693 | if (ppm) | |
694 | multi = max_t(u32, (MILLION - ppm) / 50000, 2); | |
695 | else | |
696 | multi = 2; | |
697 | period_us = multi * lat; | |
698 | period_us = clamp_t(u32, period_us, MIN_PERIOD, MAX_PERIOD); | |
699 | ||
700 | /* calculate dependent params */ | |
701 | ioc->period_us = period_us; | |
702 | ioc->margin_us = period_us * MARGIN_PCT / 100; | |
703 | ioc->inuse_margin_vtime = DIV64_U64_ROUND_UP( | |
704 | period_us * VTIME_PER_USEC * INUSE_MARGIN_PCT, 100); | |
705 | } | |
706 | ||
707 | static int ioc_autop_idx(struct ioc *ioc) | |
708 | { | |
709 | int idx = ioc->autop_idx; | |
710 | const struct ioc_params *p = &autop[idx]; | |
711 | u32 vrate_pct; | |
712 | u64 now_ns; | |
713 | ||
714 | /* rotational? */ | |
715 | if (!blk_queue_nonrot(ioc->rqos.q)) | |
716 | return AUTOP_HDD; | |
717 | ||
718 | /* handle SATA SSDs w/ broken NCQ */ | |
719 | if (blk_queue_depth(ioc->rqos.q) == 1) | |
720 | return AUTOP_SSD_QD1; | |
721 | ||
722 | /* use one of the normal ssd sets */ | |
723 | if (idx < AUTOP_SSD_DFL) | |
724 | return AUTOP_SSD_DFL; | |
725 | ||
726 | /* if user is overriding anything, maintain what was there */ | |
727 | if (ioc->user_qos_params || ioc->user_cost_model) | |
728 | return idx; | |
729 | ||
730 | /* step up/down based on the vrate */ | |
731 | vrate_pct = div64_u64(atomic64_read(&ioc->vtime_rate) * 100, | |
732 | VTIME_PER_USEC); | |
733 | now_ns = ktime_get_ns(); | |
734 | ||
735 | if (p->too_fast_vrate_pct && p->too_fast_vrate_pct <= vrate_pct) { | |
736 | if (!ioc->autop_too_fast_at) | |
737 | ioc->autop_too_fast_at = now_ns; | |
738 | if (now_ns - ioc->autop_too_fast_at >= AUTOP_CYCLE_NSEC) | |
739 | return idx + 1; | |
740 | } else { | |
741 | ioc->autop_too_fast_at = 0; | |
742 | } | |
743 | ||
744 | if (p->too_slow_vrate_pct && p->too_slow_vrate_pct >= vrate_pct) { | |
745 | if (!ioc->autop_too_slow_at) | |
746 | ioc->autop_too_slow_at = now_ns; | |
747 | if (now_ns - ioc->autop_too_slow_at >= AUTOP_CYCLE_NSEC) | |
748 | return idx - 1; | |
749 | } else { | |
750 | ioc->autop_too_slow_at = 0; | |
751 | } | |
752 | ||
753 | return idx; | |
754 | } | |
755 | ||
756 | /* | |
757 | * Take the followings as input | |
758 | * | |
759 | * @bps maximum sequential throughput | |
760 | * @seqiops maximum sequential 4k iops | |
761 | * @randiops maximum random 4k iops | |
762 | * | |
763 | * and calculate the linear model cost coefficients. | |
764 | * | |
765 | * *@page per-page cost 1s / (@bps / 4096) | |
766 | * *@seqio base cost of a seq IO max((1s / @seqiops) - *@page, 0) | |
767 | * @randiops base cost of a rand IO max((1s / @randiops) - *@page, 0) | |
768 | */ | |
769 | static void calc_lcoefs(u64 bps, u64 seqiops, u64 randiops, | |
770 | u64 *page, u64 *seqio, u64 *randio) | |
771 | { | |
772 | u64 v; | |
773 | ||
774 | *page = *seqio = *randio = 0; | |
775 | ||
776 | if (bps) | |
777 | *page = DIV64_U64_ROUND_UP(VTIME_PER_SEC, | |
778 | DIV_ROUND_UP_ULL(bps, IOC_PAGE_SIZE)); | |
779 | ||
780 | if (seqiops) { | |
781 | v = DIV64_U64_ROUND_UP(VTIME_PER_SEC, seqiops); | |
782 | if (v > *page) | |
783 | *seqio = v - *page; | |
784 | } | |
785 | ||
786 | if (randiops) { | |
787 | v = DIV64_U64_ROUND_UP(VTIME_PER_SEC, randiops); | |
788 | if (v > *page) | |
789 | *randio = v - *page; | |
790 | } | |
791 | } | |
792 | ||
793 | static void ioc_refresh_lcoefs(struct ioc *ioc) | |
794 | { | |
795 | u64 *u = ioc->params.i_lcoefs; | |
796 | u64 *c = ioc->params.lcoefs; | |
797 | ||
798 | calc_lcoefs(u[I_LCOEF_RBPS], u[I_LCOEF_RSEQIOPS], u[I_LCOEF_RRANDIOPS], | |
799 | &c[LCOEF_RPAGE], &c[LCOEF_RSEQIO], &c[LCOEF_RRANDIO]); | |
800 | calc_lcoefs(u[I_LCOEF_WBPS], u[I_LCOEF_WSEQIOPS], u[I_LCOEF_WRANDIOPS], | |
801 | &c[LCOEF_WPAGE], &c[LCOEF_WSEQIO], &c[LCOEF_WRANDIO]); | |
802 | } | |
803 | ||
804 | static bool ioc_refresh_params(struct ioc *ioc, bool force) | |
805 | { | |
806 | const struct ioc_params *p; | |
807 | int idx; | |
808 | ||
809 | lockdep_assert_held(&ioc->lock); | |
810 | ||
811 | idx = ioc_autop_idx(ioc); | |
812 | p = &autop[idx]; | |
813 | ||
814 | if (idx == ioc->autop_idx && !force) | |
815 | return false; | |
816 | ||
817 | if (idx != ioc->autop_idx) | |
818 | atomic64_set(&ioc->vtime_rate, VTIME_PER_USEC); | |
819 | ||
820 | ioc->autop_idx = idx; | |
821 | ioc->autop_too_fast_at = 0; | |
822 | ioc->autop_too_slow_at = 0; | |
823 | ||
824 | if (!ioc->user_qos_params) | |
825 | memcpy(ioc->params.qos, p->qos, sizeof(p->qos)); | |
826 | if (!ioc->user_cost_model) | |
827 | memcpy(ioc->params.i_lcoefs, p->i_lcoefs, sizeof(p->i_lcoefs)); | |
828 | ||
829 | ioc_refresh_period_us(ioc); | |
830 | ioc_refresh_lcoefs(ioc); | |
831 | ||
832 | ioc->vrate_min = DIV64_U64_ROUND_UP((u64)ioc->params.qos[QOS_MIN] * | |
833 | VTIME_PER_USEC, MILLION); | |
834 | ioc->vrate_max = div64_u64((u64)ioc->params.qos[QOS_MAX] * | |
835 | VTIME_PER_USEC, MILLION); | |
836 | ||
837 | return true; | |
838 | } | |
839 | ||
840 | /* take a snapshot of the current [v]time and vrate */ | |
841 | static void ioc_now(struct ioc *ioc, struct ioc_now *now) | |
842 | { | |
843 | unsigned seq; | |
844 | ||
845 | now->now_ns = ktime_get(); | |
846 | now->now = ktime_to_us(now->now_ns); | |
847 | now->vrate = atomic64_read(&ioc->vtime_rate); | |
848 | ||
849 | /* | |
850 | * The current vtime is | |
851 | * | |
852 | * vtime at period start + (wallclock time since the start) * vrate | |
853 | * | |
854 | * As a consistent snapshot of `period_at_vtime` and `period_at` is | |
855 | * needed, they're seqcount protected. | |
856 | */ | |
857 | do { | |
858 | seq = read_seqcount_begin(&ioc->period_seqcount); | |
859 | now->vnow = ioc->period_at_vtime + | |
860 | (now->now - ioc->period_at) * now->vrate; | |
861 | } while (read_seqcount_retry(&ioc->period_seqcount, seq)); | |
862 | } | |
863 | ||
864 | static void ioc_start_period(struct ioc *ioc, struct ioc_now *now) | |
865 | { | |
866 | lockdep_assert_held(&ioc->lock); | |
867 | WARN_ON_ONCE(ioc->running != IOC_RUNNING); | |
868 | ||
869 | write_seqcount_begin(&ioc->period_seqcount); | |
870 | ioc->period_at = now->now; | |
871 | ioc->period_at_vtime = now->vnow; | |
872 | write_seqcount_end(&ioc->period_seqcount); | |
873 | ||
874 | ioc->timer.expires = jiffies + usecs_to_jiffies(ioc->period_us); | |
875 | add_timer(&ioc->timer); | |
876 | } | |
877 | ||
878 | /* | |
879 | * Update @iocg's `active` and `inuse` to @active and @inuse, update level | |
880 | * weight sums and propagate upwards accordingly. | |
881 | */ | |
882 | static void __propagate_active_weight(struct ioc_gq *iocg, u32 active, u32 inuse) | |
883 | { | |
884 | struct ioc *ioc = iocg->ioc; | |
885 | int lvl; | |
886 | ||
887 | lockdep_assert_held(&ioc->lock); | |
888 | ||
889 | inuse = min(active, inuse); | |
890 | ||
891 | for (lvl = iocg->level - 1; lvl >= 0; lvl--) { | |
892 | struct ioc_gq *parent = iocg->ancestors[lvl]; | |
893 | struct ioc_gq *child = iocg->ancestors[lvl + 1]; | |
894 | u32 parent_active = 0, parent_inuse = 0; | |
895 | ||
896 | /* update the level sums */ | |
897 | parent->child_active_sum += (s32)(active - child->active); | |
898 | parent->child_inuse_sum += (s32)(inuse - child->inuse); | |
899 | /* apply the udpates */ | |
900 | child->active = active; | |
901 | child->inuse = inuse; | |
902 | ||
903 | /* | |
904 | * The delta between inuse and active sums indicates that | |
905 | * that much of weight is being given away. Parent's inuse | |
906 | * and active should reflect the ratio. | |
907 | */ | |
908 | if (parent->child_active_sum) { | |
909 | parent_active = parent->weight; | |
910 | parent_inuse = DIV64_U64_ROUND_UP( | |
911 | parent_active * parent->child_inuse_sum, | |
912 | parent->child_active_sum); | |
913 | } | |
914 | ||
915 | /* do we need to keep walking up? */ | |
916 | if (parent_active == parent->active && | |
917 | parent_inuse == parent->inuse) | |
918 | break; | |
919 | ||
920 | active = parent_active; | |
921 | inuse = parent_inuse; | |
922 | } | |
923 | ||
924 | ioc->weights_updated = true; | |
925 | } | |
926 | ||
927 | static void commit_active_weights(struct ioc *ioc) | |
928 | { | |
929 | lockdep_assert_held(&ioc->lock); | |
930 | ||
931 | if (ioc->weights_updated) { | |
932 | /* paired with rmb in current_hweight(), see there */ | |
933 | smp_wmb(); | |
934 | atomic_inc(&ioc->hweight_gen); | |
935 | ioc->weights_updated = false; | |
936 | } | |
937 | } | |
938 | ||
939 | static void propagate_active_weight(struct ioc_gq *iocg, u32 active, u32 inuse) | |
940 | { | |
941 | __propagate_active_weight(iocg, active, inuse); | |
942 | commit_active_weights(iocg->ioc); | |
943 | } | |
944 | ||
945 | static void current_hweight(struct ioc_gq *iocg, u32 *hw_activep, u32 *hw_inusep) | |
946 | { | |
947 | struct ioc *ioc = iocg->ioc; | |
948 | int lvl; | |
949 | u32 hwa, hwi; | |
950 | int ioc_gen; | |
951 | ||
952 | /* hot path - if uptodate, use cached */ | |
953 | ioc_gen = atomic_read(&ioc->hweight_gen); | |
954 | if (ioc_gen == iocg->hweight_gen) | |
955 | goto out; | |
956 | ||
957 | /* | |
958 | * Paired with wmb in commit_active_weights(). If we saw the | |
959 | * updated hweight_gen, all the weight updates from | |
960 | * __propagate_active_weight() are visible too. | |
961 | * | |
962 | * We can race with weight updates during calculation and get it | |
963 | * wrong. However, hweight_gen would have changed and a future | |
964 | * reader will recalculate and we're guaranteed to discard the | |
965 | * wrong result soon. | |
966 | */ | |
967 | smp_rmb(); | |
968 | ||
969 | hwa = hwi = HWEIGHT_WHOLE; | |
970 | for (lvl = 0; lvl <= iocg->level - 1; lvl++) { | |
971 | struct ioc_gq *parent = iocg->ancestors[lvl]; | |
972 | struct ioc_gq *child = iocg->ancestors[lvl + 1]; | |
973 | u32 active_sum = READ_ONCE(parent->child_active_sum); | |
974 | u32 inuse_sum = READ_ONCE(parent->child_inuse_sum); | |
975 | u32 active = READ_ONCE(child->active); | |
976 | u32 inuse = READ_ONCE(child->inuse); | |
977 | ||
978 | /* we can race with deactivations and either may read as zero */ | |
979 | if (!active_sum || !inuse_sum) | |
980 | continue; | |
981 | ||
982 | active_sum = max(active, active_sum); | |
983 | hwa = hwa * active / active_sum; /* max 16bits * 10000 */ | |
984 | ||
985 | inuse_sum = max(inuse, inuse_sum); | |
986 | hwi = hwi * inuse / inuse_sum; /* max 16bits * 10000 */ | |
987 | } | |
988 | ||
989 | iocg->hweight_active = max_t(u32, hwa, 1); | |
990 | iocg->hweight_inuse = max_t(u32, hwi, 1); | |
991 | iocg->hweight_gen = ioc_gen; | |
992 | out: | |
993 | if (hw_activep) | |
994 | *hw_activep = iocg->hweight_active; | |
995 | if (hw_inusep) | |
996 | *hw_inusep = iocg->hweight_inuse; | |
997 | } | |
998 | ||
999 | static void weight_updated(struct ioc_gq *iocg) | |
1000 | { | |
1001 | struct ioc *ioc = iocg->ioc; | |
1002 | struct blkcg_gq *blkg = iocg_to_blkg(iocg); | |
1003 | struct ioc_cgrp *iocc = blkcg_to_iocc(blkg->blkcg); | |
1004 | u32 weight; | |
1005 | ||
1006 | lockdep_assert_held(&ioc->lock); | |
1007 | ||
1008 | weight = iocg->cfg_weight ?: iocc->dfl_weight; | |
1009 | if (weight != iocg->weight && iocg->active) | |
1010 | propagate_active_weight(iocg, weight, | |
1011 | DIV64_U64_ROUND_UP(iocg->inuse * weight, iocg->weight)); | |
1012 | iocg->weight = weight; | |
1013 | } | |
1014 | ||
1015 | static bool iocg_activate(struct ioc_gq *iocg, struct ioc_now *now) | |
1016 | { | |
1017 | struct ioc *ioc = iocg->ioc; | |
1018 | u64 last_period, cur_period, max_period_delta; | |
1019 | u64 vtime, vmargin, vmin; | |
1020 | int i; | |
1021 | ||
1022 | /* | |
1023 | * If seem to be already active, just update the stamp to tell the | |
1024 | * timer that we're still active. We don't mind occassional races. | |
1025 | */ | |
1026 | if (!list_empty(&iocg->active_list)) { | |
1027 | ioc_now(ioc, now); | |
1028 | cur_period = atomic64_read(&ioc->cur_period); | |
1029 | if (atomic64_read(&iocg->active_period) != cur_period) | |
1030 | atomic64_set(&iocg->active_period, cur_period); | |
1031 | return true; | |
1032 | } | |
1033 | ||
1034 | /* racy check on internal node IOs, treat as root level IOs */ | |
1035 | if (iocg->child_active_sum) | |
1036 | return false; | |
1037 | ||
1038 | spin_lock_irq(&ioc->lock); | |
1039 | ||
1040 | ioc_now(ioc, now); | |
1041 | ||
1042 | /* update period */ | |
1043 | cur_period = atomic64_read(&ioc->cur_period); | |
1044 | last_period = atomic64_read(&iocg->active_period); | |
1045 | atomic64_set(&iocg->active_period, cur_period); | |
1046 | ||
1047 | /* already activated or breaking leaf-only constraint? */ | |
1048 | for (i = iocg->level; i > 0; i--) | |
1049 | if (!list_empty(&iocg->active_list)) | |
1050 | goto fail_unlock; | |
1051 | if (iocg->child_active_sum) | |
1052 | goto fail_unlock; | |
1053 | ||
1054 | /* | |
1055 | * vtime may wrap when vrate is raised substantially due to | |
1056 | * underestimated IO costs. Look at the period and ignore its | |
1057 | * vtime if the iocg has been idle for too long. Also, cap the | |
1058 | * budget it can start with to the margin. | |
1059 | */ | |
1060 | max_period_delta = DIV64_U64_ROUND_UP(VTIME_VALID_DUR, ioc->period_us); | |
1061 | vtime = atomic64_read(&iocg->vtime); | |
1062 | vmargin = ioc->margin_us * now->vrate; | |
1063 | vmin = now->vnow - vmargin; | |
1064 | ||
1065 | if (last_period + max_period_delta < cur_period || | |
1066 | time_before64(vtime, vmin)) { | |
1067 | atomic64_add(vmin - vtime, &iocg->vtime); | |
1068 | atomic64_add(vmin - vtime, &iocg->done_vtime); | |
1069 | vtime = vmin; | |
1070 | } | |
1071 | ||
1072 | /* | |
1073 | * Activate, propagate weight and start period timer if not | |
1074 | * running. Reset hweight_gen to avoid accidental match from | |
1075 | * wrapping. | |
1076 | */ | |
1077 | iocg->hweight_gen = atomic_read(&ioc->hweight_gen) - 1; | |
1078 | list_add(&iocg->active_list, &ioc->active_iocgs); | |
1079 | propagate_active_weight(iocg, iocg->weight, | |
1080 | iocg->last_inuse ?: iocg->weight); | |
1081 | ||
1082 | TRACE_IOCG_PATH(iocg_activate, iocg, now, | |
1083 | last_period, cur_period, vtime); | |
1084 | ||
1085 | iocg->last_vtime = vtime; | |
1086 | ||
1087 | if (ioc->running == IOC_IDLE) { | |
1088 | ioc->running = IOC_RUNNING; | |
1089 | ioc_start_period(ioc, now); | |
1090 | } | |
1091 | ||
1092 | spin_unlock_irq(&ioc->lock); | |
1093 | return true; | |
1094 | ||
1095 | fail_unlock: | |
1096 | spin_unlock_irq(&ioc->lock); | |
1097 | return false; | |
1098 | } | |
1099 | ||
1100 | static int iocg_wake_fn(struct wait_queue_entry *wq_entry, unsigned mode, | |
1101 | int flags, void *key) | |
1102 | { | |
1103 | struct iocg_wait *wait = container_of(wq_entry, struct iocg_wait, wait); | |
1104 | struct iocg_wake_ctx *ctx = (struct iocg_wake_ctx *)key; | |
1105 | u64 cost = abs_cost_to_cost(wait->abs_cost, ctx->hw_inuse); | |
1106 | ||
1107 | ctx->vbudget -= cost; | |
1108 | ||
1109 | if (ctx->vbudget < 0) | |
1110 | return -1; | |
1111 | ||
1112 | iocg_commit_bio(ctx->iocg, wait->bio, cost); | |
1113 | ||
1114 | /* | |
1115 | * autoremove_wake_function() removes the wait entry only when it | |
1116 | * actually changed the task state. We want the wait always | |
1117 | * removed. Remove explicitly and use default_wake_function(). | |
1118 | */ | |
1119 | list_del_init(&wq_entry->entry); | |
1120 | wait->committed = true; | |
1121 | ||
1122 | default_wake_function(wq_entry, mode, flags, key); | |
1123 | return 0; | |
1124 | } | |
1125 | ||
1126 | static void iocg_kick_waitq(struct ioc_gq *iocg, struct ioc_now *now) | |
1127 | { | |
1128 | struct ioc *ioc = iocg->ioc; | |
1129 | struct iocg_wake_ctx ctx = { .iocg = iocg }; | |
1130 | u64 margin_ns = (u64)(ioc->period_us * | |
1131 | WAITQ_TIMER_MARGIN_PCT / 100) * NSEC_PER_USEC; | |
1132 | u64 vshortage, expires, oexpires; | |
1133 | ||
1134 | lockdep_assert_held(&iocg->waitq.lock); | |
1135 | ||
1136 | /* | |
1137 | * Wake up the ones which are due and see how much vtime we'll need | |
1138 | * for the next one. | |
1139 | */ | |
1140 | current_hweight(iocg, NULL, &ctx.hw_inuse); | |
1141 | ctx.vbudget = now->vnow - atomic64_read(&iocg->vtime); | |
1142 | __wake_up_locked_key(&iocg->waitq, TASK_NORMAL, &ctx); | |
1143 | if (!waitqueue_active(&iocg->waitq)) | |
1144 | return; | |
1145 | if (WARN_ON_ONCE(ctx.vbudget >= 0)) | |
1146 | return; | |
1147 | ||
1148 | /* determine next wakeup, add a quarter margin to guarantee chunking */ | |
1149 | vshortage = -ctx.vbudget; | |
1150 | expires = now->now_ns + | |
1151 | DIV64_U64_ROUND_UP(vshortage, now->vrate) * NSEC_PER_USEC; | |
1152 | expires += margin_ns / 4; | |
1153 | ||
1154 | /* if already active and close enough, don't bother */ | |
1155 | oexpires = ktime_to_ns(hrtimer_get_softexpires(&iocg->waitq_timer)); | |
1156 | if (hrtimer_is_queued(&iocg->waitq_timer) && | |
1157 | abs(oexpires - expires) <= margin_ns / 4) | |
1158 | return; | |
1159 | ||
1160 | hrtimer_start_range_ns(&iocg->waitq_timer, ns_to_ktime(expires), | |
1161 | margin_ns / 4, HRTIMER_MODE_ABS); | |
1162 | } | |
1163 | ||
1164 | static enum hrtimer_restart iocg_waitq_timer_fn(struct hrtimer *timer) | |
1165 | { | |
1166 | struct ioc_gq *iocg = container_of(timer, struct ioc_gq, waitq_timer); | |
1167 | struct ioc_now now; | |
1168 | unsigned long flags; | |
1169 | ||
1170 | ioc_now(iocg->ioc, &now); | |
1171 | ||
1172 | spin_lock_irqsave(&iocg->waitq.lock, flags); | |
1173 | iocg_kick_waitq(iocg, &now); | |
1174 | spin_unlock_irqrestore(&iocg->waitq.lock, flags); | |
1175 | ||
1176 | return HRTIMER_NORESTART; | |
1177 | } | |
1178 | ||
1179 | static void iocg_kick_delay(struct ioc_gq *iocg, struct ioc_now *now, u64 cost) | |
1180 | { | |
1181 | struct ioc *ioc = iocg->ioc; | |
1182 | struct blkcg_gq *blkg = iocg_to_blkg(iocg); | |
1183 | u64 vtime = atomic64_read(&iocg->vtime); | |
1184 | u64 vmargin = ioc->margin_us * now->vrate; | |
1185 | u64 margin_ns = ioc->margin_us * NSEC_PER_USEC; | |
1186 | u64 expires, oexpires; | |
1187 | ||
1188 | /* clear or maintain depending on the overage */ | |
1189 | if (time_before_eq64(vtime, now->vnow)) { | |
1190 | blkcg_clear_delay(blkg); | |
1191 | return; | |
1192 | } | |
1193 | if (!atomic_read(&blkg->use_delay) && | |
1194 | time_before_eq64(vtime, now->vnow + vmargin)) | |
1195 | return; | |
1196 | ||
1197 | /* use delay */ | |
1198 | if (cost) { | |
1199 | u64 cost_ns = DIV64_U64_ROUND_UP(cost * NSEC_PER_USEC, | |
1200 | now->vrate); | |
1201 | blkcg_add_delay(blkg, now->now_ns, cost_ns); | |
1202 | } | |
1203 | blkcg_use_delay(blkg); | |
1204 | ||
1205 | expires = now->now_ns + DIV64_U64_ROUND_UP(vtime - now->vnow, | |
1206 | now->vrate) * NSEC_PER_USEC; | |
1207 | ||
1208 | /* if already active and close enough, don't bother */ | |
1209 | oexpires = ktime_to_ns(hrtimer_get_softexpires(&iocg->delay_timer)); | |
1210 | if (hrtimer_is_queued(&iocg->delay_timer) && | |
1211 | abs(oexpires - expires) <= margin_ns / 4) | |
1212 | return; | |
1213 | ||
1214 | hrtimer_start_range_ns(&iocg->delay_timer, ns_to_ktime(expires), | |
1215 | margin_ns / 4, HRTIMER_MODE_ABS); | |
1216 | } | |
1217 | ||
1218 | static enum hrtimer_restart iocg_delay_timer_fn(struct hrtimer *timer) | |
1219 | { | |
1220 | struct ioc_gq *iocg = container_of(timer, struct ioc_gq, delay_timer); | |
1221 | struct ioc_now now; | |
1222 | ||
1223 | ioc_now(iocg->ioc, &now); | |
1224 | iocg_kick_delay(iocg, &now, 0); | |
1225 | ||
1226 | return HRTIMER_NORESTART; | |
1227 | } | |
1228 | ||
1229 | static void ioc_lat_stat(struct ioc *ioc, u32 *missed_ppm_ar, u32 *rq_wait_pct_p) | |
1230 | { | |
1231 | u32 nr_met[2] = { }; | |
1232 | u32 nr_missed[2] = { }; | |
1233 | u64 rq_wait_ns = 0; | |
1234 | int cpu, rw; | |
1235 | ||
1236 | for_each_online_cpu(cpu) { | |
1237 | struct ioc_pcpu_stat *stat = per_cpu_ptr(ioc->pcpu_stat, cpu); | |
1238 | u64 this_rq_wait_ns; | |
1239 | ||
1240 | for (rw = READ; rw <= WRITE; rw++) { | |
1241 | u32 this_met = READ_ONCE(stat->missed[rw].nr_met); | |
1242 | u32 this_missed = READ_ONCE(stat->missed[rw].nr_missed); | |
1243 | ||
1244 | nr_met[rw] += this_met - stat->missed[rw].last_met; | |
1245 | nr_missed[rw] += this_missed - stat->missed[rw].last_missed; | |
1246 | stat->missed[rw].last_met = this_met; | |
1247 | stat->missed[rw].last_missed = this_missed; | |
1248 | } | |
1249 | ||
1250 | this_rq_wait_ns = READ_ONCE(stat->rq_wait_ns); | |
1251 | rq_wait_ns += this_rq_wait_ns - stat->last_rq_wait_ns; | |
1252 | stat->last_rq_wait_ns = this_rq_wait_ns; | |
1253 | } | |
1254 | ||
1255 | for (rw = READ; rw <= WRITE; rw++) { | |
1256 | if (nr_met[rw] + nr_missed[rw]) | |
1257 | missed_ppm_ar[rw] = | |
1258 | DIV64_U64_ROUND_UP((u64)nr_missed[rw] * MILLION, | |
1259 | nr_met[rw] + nr_missed[rw]); | |
1260 | else | |
1261 | missed_ppm_ar[rw] = 0; | |
1262 | } | |
1263 | ||
1264 | *rq_wait_pct_p = div64_u64(rq_wait_ns * 100, | |
1265 | ioc->period_us * NSEC_PER_USEC); | |
1266 | } | |
1267 | ||
1268 | /* was iocg idle this period? */ | |
1269 | static bool iocg_is_idle(struct ioc_gq *iocg) | |
1270 | { | |
1271 | struct ioc *ioc = iocg->ioc; | |
1272 | ||
1273 | /* did something get issued this period? */ | |
1274 | if (atomic64_read(&iocg->active_period) == | |
1275 | atomic64_read(&ioc->cur_period)) | |
1276 | return false; | |
1277 | ||
1278 | /* is something in flight? */ | |
1279 | if (atomic64_read(&iocg->done_vtime) < atomic64_read(&iocg->vtime)) | |
1280 | return false; | |
1281 | ||
1282 | return true; | |
1283 | } | |
1284 | ||
1285 | /* returns usage with margin added if surplus is large enough */ | |
1286 | static u32 surplus_adjusted_hweight_inuse(u32 usage, u32 hw_inuse) | |
1287 | { | |
1288 | /* add margin */ | |
1289 | usage = DIV_ROUND_UP(usage * SURPLUS_SCALE_PCT, 100); | |
1290 | usage += SURPLUS_SCALE_ABS; | |
1291 | ||
1292 | /* don't bother if the surplus is too small */ | |
1293 | if (usage + SURPLUS_MIN_ADJ_DELTA > hw_inuse) | |
1294 | return 0; | |
1295 | ||
1296 | return usage; | |
1297 | } | |
1298 | ||
1299 | static void ioc_timer_fn(struct timer_list *timer) | |
1300 | { | |
1301 | struct ioc *ioc = container_of(timer, struct ioc, timer); | |
1302 | struct ioc_gq *iocg, *tiocg; | |
1303 | struct ioc_now now; | |
1304 | int nr_surpluses = 0, nr_shortages = 0, nr_lagging = 0; | |
1305 | u32 ppm_rthr = MILLION - ioc->params.qos[QOS_RPPM]; | |
1306 | u32 ppm_wthr = MILLION - ioc->params.qos[QOS_WPPM]; | |
1307 | u32 missed_ppm[2], rq_wait_pct; | |
1308 | u64 period_vtime; | |
1309 | int i; | |
1310 | ||
1311 | /* how were the latencies during the period? */ | |
1312 | ioc_lat_stat(ioc, missed_ppm, &rq_wait_pct); | |
1313 | ||
1314 | /* take care of active iocgs */ | |
1315 | spin_lock_irq(&ioc->lock); | |
1316 | ||
1317 | ioc_now(ioc, &now); | |
1318 | ||
1319 | period_vtime = now.vnow - ioc->period_at_vtime; | |
1320 | if (WARN_ON_ONCE(!period_vtime)) { | |
1321 | spin_unlock_irq(&ioc->lock); | |
1322 | return; | |
1323 | } | |
1324 | ||
1325 | /* | |
1326 | * Waiters determine the sleep durations based on the vrate they | |
1327 | * saw at the time of sleep. If vrate has increased, some waiters | |
1328 | * could be sleeping for too long. Wake up tardy waiters which | |
1329 | * should have woken up in the last period and expire idle iocgs. | |
1330 | */ | |
1331 | list_for_each_entry_safe(iocg, tiocg, &ioc->active_iocgs, active_list) { | |
1332 | if (!waitqueue_active(&iocg->waitq) && !iocg_is_idle(iocg)) | |
1333 | continue; | |
1334 | ||
1335 | spin_lock(&iocg->waitq.lock); | |
1336 | ||
1337 | if (waitqueue_active(&iocg->waitq)) { | |
1338 | /* might be oversleeping vtime / hweight changes, kick */ | |
1339 | iocg_kick_waitq(iocg, &now); | |
1340 | iocg_kick_delay(iocg, &now, 0); | |
1341 | } else if (iocg_is_idle(iocg)) { | |
1342 | /* no waiter and idle, deactivate */ | |
1343 | iocg->last_inuse = iocg->inuse; | |
1344 | __propagate_active_weight(iocg, 0, 0); | |
1345 | list_del_init(&iocg->active_list); | |
1346 | } | |
1347 | ||
1348 | spin_unlock(&iocg->waitq.lock); | |
1349 | } | |
1350 | commit_active_weights(ioc); | |
1351 | ||
1352 | /* calc usages and see whether some weights need to be moved around */ | |
1353 | list_for_each_entry(iocg, &ioc->active_iocgs, active_list) { | |
1354 | u64 vdone, vtime, vusage, vmargin, vmin; | |
1355 | u32 hw_active, hw_inuse, usage; | |
1356 | ||
1357 | /* | |
1358 | * Collect unused and wind vtime closer to vnow to prevent | |
1359 | * iocgs from accumulating a large amount of budget. | |
1360 | */ | |
1361 | vdone = atomic64_read(&iocg->done_vtime); | |
1362 | vtime = atomic64_read(&iocg->vtime); | |
1363 | current_hweight(iocg, &hw_active, &hw_inuse); | |
1364 | ||
1365 | /* | |
1366 | * Latency QoS detection doesn't account for IOs which are | |
1367 | * in-flight for longer than a period. Detect them by | |
1368 | * comparing vdone against period start. If lagging behind | |
1369 | * IOs from past periods, don't increase vrate. | |
1370 | */ | |
1371 | if (!atomic_read(&iocg_to_blkg(iocg)->use_delay) && | |
1372 | time_after64(vtime, vdone) && | |
1373 | time_after64(vtime, now.vnow - | |
1374 | MAX_LAGGING_PERIODS * period_vtime) && | |
1375 | time_before64(vdone, now.vnow - period_vtime)) | |
1376 | nr_lagging++; | |
1377 | ||
1378 | if (waitqueue_active(&iocg->waitq)) | |
1379 | vusage = now.vnow - iocg->last_vtime; | |
1380 | else if (time_before64(iocg->last_vtime, vtime)) | |
1381 | vusage = vtime - iocg->last_vtime; | |
1382 | else | |
1383 | vusage = 0; | |
1384 | ||
1385 | iocg->last_vtime += vusage; | |
1386 | /* | |
1387 | * Factor in in-flight vtime into vusage to avoid | |
1388 | * high-latency completions appearing as idle. This should | |
1389 | * be done after the above ->last_time adjustment. | |
1390 | */ | |
1391 | vusage = max(vusage, vtime - vdone); | |
1392 | ||
1393 | /* calculate hweight based usage ratio and record */ | |
1394 | if (vusage) { | |
1395 | usage = DIV64_U64_ROUND_UP(vusage * hw_inuse, | |
1396 | period_vtime); | |
1397 | iocg->usage_idx = (iocg->usage_idx + 1) % NR_USAGE_SLOTS; | |
1398 | iocg->usages[iocg->usage_idx] = usage; | |
1399 | } else { | |
1400 | usage = 0; | |
1401 | } | |
1402 | ||
1403 | /* see whether there's surplus vtime */ | |
1404 | vmargin = ioc->margin_us * now.vrate; | |
1405 | vmin = now.vnow - vmargin; | |
1406 | ||
1407 | iocg->has_surplus = false; | |
1408 | ||
1409 | if (!waitqueue_active(&iocg->waitq) && | |
1410 | time_before64(vtime, vmin)) { | |
1411 | u64 delta = vmin - vtime; | |
1412 | ||
1413 | /* throw away surplus vtime */ | |
1414 | atomic64_add(delta, &iocg->vtime); | |
1415 | atomic64_add(delta, &iocg->done_vtime); | |
1416 | iocg->last_vtime += delta; | |
1417 | /* if usage is sufficiently low, maybe it can donate */ | |
1418 | if (surplus_adjusted_hweight_inuse(usage, hw_inuse)) { | |
1419 | iocg->has_surplus = true; | |
1420 | nr_surpluses++; | |
1421 | } | |
1422 | } else if (hw_inuse < hw_active) { | |
1423 | u32 new_hwi, new_inuse; | |
1424 | ||
1425 | /* was donating but might need to take back some */ | |
1426 | if (waitqueue_active(&iocg->waitq)) { | |
1427 | new_hwi = hw_active; | |
1428 | } else { | |
1429 | new_hwi = max(hw_inuse, | |
1430 | usage * SURPLUS_SCALE_PCT / 100 + | |
1431 | SURPLUS_SCALE_ABS); | |
1432 | } | |
1433 | ||
1434 | new_inuse = div64_u64((u64)iocg->inuse * new_hwi, | |
1435 | hw_inuse); | |
1436 | new_inuse = clamp_t(u32, new_inuse, 1, iocg->active); | |
1437 | ||
1438 | if (new_inuse > iocg->inuse) { | |
1439 | TRACE_IOCG_PATH(inuse_takeback, iocg, &now, | |
1440 | iocg->inuse, new_inuse, | |
1441 | hw_inuse, new_hwi); | |
1442 | __propagate_active_weight(iocg, iocg->weight, | |
1443 | new_inuse); | |
1444 | } | |
1445 | } else { | |
1446 | /* genuninely out of vtime */ | |
1447 | nr_shortages++; | |
1448 | } | |
1449 | } | |
1450 | ||
1451 | if (!nr_shortages || !nr_surpluses) | |
1452 | goto skip_surplus_transfers; | |
1453 | ||
1454 | /* there are both shortages and surpluses, transfer surpluses */ | |
1455 | list_for_each_entry(iocg, &ioc->active_iocgs, active_list) { | |
1456 | u32 usage, hw_active, hw_inuse, new_hwi, new_inuse; | |
1457 | int nr_valid = 0; | |
1458 | ||
1459 | if (!iocg->has_surplus) | |
1460 | continue; | |
1461 | ||
1462 | /* base the decision on max historical usage */ | |
1463 | for (i = 0, usage = 0; i < NR_USAGE_SLOTS; i++) { | |
1464 | if (iocg->usages[i]) { | |
1465 | usage = max(usage, iocg->usages[i]); | |
1466 | nr_valid++; | |
1467 | } | |
1468 | } | |
1469 | if (nr_valid < MIN_VALID_USAGES) | |
1470 | continue; | |
1471 | ||
1472 | current_hweight(iocg, &hw_active, &hw_inuse); | |
1473 | new_hwi = surplus_adjusted_hweight_inuse(usage, hw_inuse); | |
1474 | if (!new_hwi) | |
1475 | continue; | |
1476 | ||
1477 | new_inuse = DIV64_U64_ROUND_UP((u64)iocg->inuse * new_hwi, | |
1478 | hw_inuse); | |
1479 | if (new_inuse < iocg->inuse) { | |
1480 | TRACE_IOCG_PATH(inuse_giveaway, iocg, &now, | |
1481 | iocg->inuse, new_inuse, | |
1482 | hw_inuse, new_hwi); | |
1483 | __propagate_active_weight(iocg, iocg->weight, new_inuse); | |
1484 | } | |
1485 | } | |
1486 | skip_surplus_transfers: | |
1487 | commit_active_weights(ioc); | |
1488 | ||
1489 | /* | |
1490 | * If q is getting clogged or we're missing too much, we're issuing | |
1491 | * too much IO and should lower vtime rate. If we're not missing | |
1492 | * and experiencing shortages but not surpluses, we're too stingy | |
1493 | * and should increase vtime rate. | |
1494 | */ | |
1495 | if (rq_wait_pct > RQ_WAIT_BUSY_PCT || | |
1496 | missed_ppm[READ] > ppm_rthr || | |
1497 | missed_ppm[WRITE] > ppm_wthr) { | |
1498 | ioc->busy_level = max(ioc->busy_level, 0); | |
1499 | ioc->busy_level++; | |
1500 | } else if (nr_lagging) { | |
1501 | ioc->busy_level = max(ioc->busy_level, 0); | |
1502 | } else if (nr_shortages && !nr_surpluses && | |
1503 | rq_wait_pct <= RQ_WAIT_BUSY_PCT * UNBUSY_THR_PCT / 100 && | |
1504 | missed_ppm[READ] <= ppm_rthr * UNBUSY_THR_PCT / 100 && | |
1505 | missed_ppm[WRITE] <= ppm_wthr * UNBUSY_THR_PCT / 100) { | |
1506 | ioc->busy_level = min(ioc->busy_level, 0); | |
1507 | ioc->busy_level--; | |
1508 | } else { | |
1509 | ioc->busy_level = 0; | |
1510 | } | |
1511 | ||
1512 | ioc->busy_level = clamp(ioc->busy_level, -1000, 1000); | |
1513 | ||
1514 | if (ioc->busy_level) { | |
1515 | u64 vrate = atomic64_read(&ioc->vtime_rate); | |
1516 | u64 vrate_min = ioc->vrate_min, vrate_max = ioc->vrate_max; | |
1517 | ||
1518 | /* rq_wait signal is always reliable, ignore user vrate_min */ | |
1519 | if (rq_wait_pct > RQ_WAIT_BUSY_PCT) | |
1520 | vrate_min = VRATE_MIN; | |
1521 | ||
1522 | /* | |
1523 | * If vrate is out of bounds, apply clamp gradually as the | |
1524 | * bounds can change abruptly. Otherwise, apply busy_level | |
1525 | * based adjustment. | |
1526 | */ | |
1527 | if (vrate < vrate_min) { | |
1528 | vrate = div64_u64(vrate * (100 + VRATE_CLAMP_ADJ_PCT), | |
1529 | 100); | |
1530 | vrate = min(vrate, vrate_min); | |
1531 | } else if (vrate > vrate_max) { | |
1532 | vrate = div64_u64(vrate * (100 - VRATE_CLAMP_ADJ_PCT), | |
1533 | 100); | |
1534 | vrate = max(vrate, vrate_max); | |
1535 | } else { | |
1536 | int idx = min_t(int, abs(ioc->busy_level), | |
1537 | ARRAY_SIZE(vrate_adj_pct) - 1); | |
1538 | u32 adj_pct = vrate_adj_pct[idx]; | |
1539 | ||
1540 | if (ioc->busy_level > 0) | |
1541 | adj_pct = 100 - adj_pct; | |
1542 | else | |
1543 | adj_pct = 100 + adj_pct; | |
1544 | ||
1545 | vrate = clamp(DIV64_U64_ROUND_UP(vrate * adj_pct, 100), | |
1546 | vrate_min, vrate_max); | |
1547 | } | |
1548 | ||
1549 | trace_iocost_ioc_vrate_adj(ioc, vrate, &missed_ppm, rq_wait_pct, | |
1550 | nr_lagging, nr_shortages, | |
1551 | nr_surpluses); | |
1552 | ||
1553 | atomic64_set(&ioc->vtime_rate, vrate); | |
1554 | ioc->inuse_margin_vtime = DIV64_U64_ROUND_UP( | |
1555 | ioc->period_us * vrate * INUSE_MARGIN_PCT, 100); | |
1556 | } | |
1557 | ||
1558 | ioc_refresh_params(ioc, false); | |
1559 | ||
1560 | /* | |
1561 | * This period is done. Move onto the next one. If nothing's | |
1562 | * going on with the device, stop the timer. | |
1563 | */ | |
1564 | atomic64_inc(&ioc->cur_period); | |
1565 | ||
1566 | if (ioc->running != IOC_STOP) { | |
1567 | if (!list_empty(&ioc->active_iocgs)) { | |
1568 | ioc_start_period(ioc, &now); | |
1569 | } else { | |
1570 | ioc->busy_level = 0; | |
1571 | ioc->running = IOC_IDLE; | |
1572 | } | |
1573 | } | |
1574 | ||
1575 | spin_unlock_irq(&ioc->lock); | |
1576 | } | |
1577 | ||
1578 | static void calc_vtime_cost_builtin(struct bio *bio, struct ioc_gq *iocg, | |
1579 | bool is_merge, u64 *costp) | |
1580 | { | |
1581 | struct ioc *ioc = iocg->ioc; | |
1582 | u64 coef_seqio, coef_randio, coef_page; | |
1583 | u64 pages = max_t(u64, bio_sectors(bio) >> IOC_SECT_TO_PAGE_SHIFT, 1); | |
1584 | u64 seek_pages = 0; | |
1585 | u64 cost = 0; | |
1586 | ||
1587 | switch (bio_op(bio)) { | |
1588 | case REQ_OP_READ: | |
1589 | coef_seqio = ioc->params.lcoefs[LCOEF_RSEQIO]; | |
1590 | coef_randio = ioc->params.lcoefs[LCOEF_RRANDIO]; | |
1591 | coef_page = ioc->params.lcoefs[LCOEF_RPAGE]; | |
1592 | break; | |
1593 | case REQ_OP_WRITE: | |
1594 | coef_seqio = ioc->params.lcoefs[LCOEF_WSEQIO]; | |
1595 | coef_randio = ioc->params.lcoefs[LCOEF_WRANDIO]; | |
1596 | coef_page = ioc->params.lcoefs[LCOEF_WPAGE]; | |
1597 | break; | |
1598 | default: | |
1599 | goto out; | |
1600 | } | |
1601 | ||
1602 | if (iocg->cursor) { | |
1603 | seek_pages = abs(bio->bi_iter.bi_sector - iocg->cursor); | |
1604 | seek_pages >>= IOC_SECT_TO_PAGE_SHIFT; | |
1605 | } | |
1606 | ||
1607 | if (!is_merge) { | |
1608 | if (seek_pages > LCOEF_RANDIO_PAGES) { | |
1609 | cost += coef_randio; | |
1610 | } else { | |
1611 | cost += coef_seqio; | |
1612 | } | |
1613 | } | |
1614 | cost += pages * coef_page; | |
1615 | out: | |
1616 | *costp = cost; | |
1617 | } | |
1618 | ||
1619 | static u64 calc_vtime_cost(struct bio *bio, struct ioc_gq *iocg, bool is_merge) | |
1620 | { | |
1621 | u64 cost; | |
1622 | ||
1623 | calc_vtime_cost_builtin(bio, iocg, is_merge, &cost); | |
1624 | return cost; | |
1625 | } | |
1626 | ||
1627 | static void ioc_rqos_throttle(struct rq_qos *rqos, struct bio *bio) | |
1628 | { | |
1629 | struct blkcg_gq *blkg = bio->bi_blkg; | |
1630 | struct ioc *ioc = rqos_to_ioc(rqos); | |
1631 | struct ioc_gq *iocg = blkg_to_iocg(blkg); | |
1632 | struct ioc_now now; | |
1633 | struct iocg_wait wait; | |
1634 | u32 hw_active, hw_inuse; | |
1635 | u64 abs_cost, cost, vtime; | |
1636 | ||
1637 | /* bypass IOs if disabled or for root cgroup */ | |
1638 | if (!ioc->enabled || !iocg->level) | |
1639 | return; | |
1640 | ||
1641 | /* always activate so that even 0 cost IOs get protected to some level */ | |
1642 | if (!iocg_activate(iocg, &now)) | |
1643 | return; | |
1644 | ||
1645 | /* calculate the absolute vtime cost */ | |
1646 | abs_cost = calc_vtime_cost(bio, iocg, false); | |
1647 | if (!abs_cost) | |
1648 | return; | |
1649 | ||
1650 | iocg->cursor = bio_end_sector(bio); | |
1651 | ||
1652 | vtime = atomic64_read(&iocg->vtime); | |
1653 | current_hweight(iocg, &hw_active, &hw_inuse); | |
1654 | ||
1655 | if (hw_inuse < hw_active && | |
1656 | time_after_eq64(vtime + ioc->inuse_margin_vtime, now.vnow)) { | |
1657 | TRACE_IOCG_PATH(inuse_reset, iocg, &now, | |
1658 | iocg->inuse, iocg->weight, hw_inuse, hw_active); | |
1659 | spin_lock_irq(&ioc->lock); | |
1660 | propagate_active_weight(iocg, iocg->weight, iocg->weight); | |
1661 | spin_unlock_irq(&ioc->lock); | |
1662 | current_hweight(iocg, &hw_active, &hw_inuse); | |
1663 | } | |
1664 | ||
1665 | cost = abs_cost_to_cost(abs_cost, hw_inuse); | |
1666 | ||
1667 | /* | |
1668 | * If no one's waiting and within budget, issue right away. The | |
1669 | * tests are racy but the races aren't systemic - we only miss once | |
1670 | * in a while which is fine. | |
1671 | */ | |
1672 | if (!waitqueue_active(&iocg->waitq) && | |
1673 | time_before_eq64(vtime + cost, now.vnow)) { | |
1674 | iocg_commit_bio(iocg, bio, cost); | |
1675 | return; | |
1676 | } | |
1677 | ||
1678 | if (bio_issue_as_root_blkg(bio) || fatal_signal_pending(current)) { | |
1679 | iocg_commit_bio(iocg, bio, cost); | |
1680 | iocg_kick_delay(iocg, &now, cost); | |
1681 | return; | |
1682 | } | |
1683 | ||
1684 | /* | |
1685 | * Append self to the waitq and schedule the wakeup timer if we're | |
1686 | * the first waiter. The timer duration is calculated based on the | |
1687 | * current vrate. vtime and hweight changes can make it too short | |
1688 | * or too long. Each wait entry records the absolute cost it's | |
1689 | * waiting for to allow re-evaluation using a custom wait entry. | |
1690 | * | |
1691 | * If too short, the timer simply reschedules itself. If too long, | |
1692 | * the period timer will notice and trigger wakeups. | |
1693 | * | |
1694 | * All waiters are on iocg->waitq and the wait states are | |
1695 | * synchronized using waitq.lock. | |
1696 | */ | |
1697 | spin_lock_irq(&iocg->waitq.lock); | |
1698 | ||
1699 | /* | |
1700 | * We activated above but w/o any synchronization. Deactivation is | |
1701 | * synchronized with waitq.lock and we won't get deactivated as | |
1702 | * long as we're waiting, so we're good if we're activated here. | |
1703 | * In the unlikely case that we are deactivated, just issue the IO. | |
1704 | */ | |
1705 | if (unlikely(list_empty(&iocg->active_list))) { | |
1706 | spin_unlock_irq(&iocg->waitq.lock); | |
1707 | iocg_commit_bio(iocg, bio, cost); | |
1708 | return; | |
1709 | } | |
1710 | ||
1711 | init_waitqueue_func_entry(&wait.wait, iocg_wake_fn); | |
1712 | wait.wait.private = current; | |
1713 | wait.bio = bio; | |
1714 | wait.abs_cost = abs_cost; | |
1715 | wait.committed = false; /* will be set true by waker */ | |
1716 | ||
1717 | __add_wait_queue_entry_tail(&iocg->waitq, &wait.wait); | |
1718 | iocg_kick_waitq(iocg, &now); | |
1719 | ||
1720 | spin_unlock_irq(&iocg->waitq.lock); | |
1721 | ||
1722 | while (true) { | |
1723 | set_current_state(TASK_UNINTERRUPTIBLE); | |
1724 | if (wait.committed) | |
1725 | break; | |
1726 | io_schedule(); | |
1727 | } | |
1728 | ||
1729 | /* waker already committed us, proceed */ | |
1730 | finish_wait(&iocg->waitq, &wait.wait); | |
1731 | } | |
1732 | ||
1733 | static void ioc_rqos_merge(struct rq_qos *rqos, struct request *rq, | |
1734 | struct bio *bio) | |
1735 | { | |
1736 | struct ioc_gq *iocg = blkg_to_iocg(bio->bi_blkg); | |
1737 | sector_t bio_end = bio_end_sector(bio); | |
1738 | u32 hw_inuse; | |
1739 | u64 abs_cost, cost; | |
1740 | ||
1741 | /* add iff the existing request has cost assigned */ | |
1742 | if (!rq->bio || !rq->bio->bi_iocost_cost) | |
1743 | return; | |
1744 | ||
1745 | abs_cost = calc_vtime_cost(bio, iocg, true); | |
1746 | if (!abs_cost) | |
1747 | return; | |
1748 | ||
1749 | /* update cursor if backmerging into the request at the cursor */ | |
1750 | if (blk_rq_pos(rq) < bio_end && | |
1751 | blk_rq_pos(rq) + blk_rq_sectors(rq) == iocg->cursor) | |
1752 | iocg->cursor = bio_end; | |
1753 | ||
1754 | current_hweight(iocg, NULL, &hw_inuse); | |
1755 | cost = div64_u64(abs_cost * HWEIGHT_WHOLE, hw_inuse); | |
1756 | bio->bi_iocost_cost = cost; | |
1757 | ||
1758 | atomic64_add(cost, &iocg->vtime); | |
1759 | } | |
1760 | ||
1761 | static void ioc_rqos_done_bio(struct rq_qos *rqos, struct bio *bio) | |
1762 | { | |
1763 | struct ioc_gq *iocg = blkg_to_iocg(bio->bi_blkg); | |
1764 | ||
1765 | if (iocg && bio->bi_iocost_cost) | |
1766 | atomic64_add(bio->bi_iocost_cost, &iocg->done_vtime); | |
1767 | } | |
1768 | ||
1769 | static void ioc_rqos_done(struct rq_qos *rqos, struct request *rq) | |
1770 | { | |
1771 | struct ioc *ioc = rqos_to_ioc(rqos); | |
1772 | u64 on_q_ns, rq_wait_ns; | |
1773 | int pidx, rw; | |
1774 | ||
1775 | if (!ioc->enabled || !rq->alloc_time_ns || !rq->start_time_ns) | |
1776 | return; | |
1777 | ||
1778 | switch (req_op(rq) & REQ_OP_MASK) { | |
1779 | case REQ_OP_READ: | |
1780 | pidx = QOS_RLAT; | |
1781 | rw = READ; | |
1782 | break; | |
1783 | case REQ_OP_WRITE: | |
1784 | pidx = QOS_WLAT; | |
1785 | rw = WRITE; | |
1786 | break; | |
1787 | default: | |
1788 | return; | |
1789 | } | |
1790 | ||
1791 | on_q_ns = ktime_get_ns() - rq->alloc_time_ns; | |
1792 | rq_wait_ns = rq->start_time_ns - rq->alloc_time_ns; | |
1793 | ||
1794 | if (on_q_ns <= ioc->params.qos[pidx] * NSEC_PER_USEC) | |
1795 | this_cpu_inc(ioc->pcpu_stat->missed[rw].nr_met); | |
1796 | else | |
1797 | this_cpu_inc(ioc->pcpu_stat->missed[rw].nr_missed); | |
1798 | ||
1799 | this_cpu_add(ioc->pcpu_stat->rq_wait_ns, rq_wait_ns); | |
1800 | } | |
1801 | ||
1802 | static void ioc_rqos_queue_depth_changed(struct rq_qos *rqos) | |
1803 | { | |
1804 | struct ioc *ioc = rqos_to_ioc(rqos); | |
1805 | ||
1806 | spin_lock_irq(&ioc->lock); | |
1807 | ioc_refresh_params(ioc, false); | |
1808 | spin_unlock_irq(&ioc->lock); | |
1809 | } | |
1810 | ||
1811 | static void ioc_rqos_exit(struct rq_qos *rqos) | |
1812 | { | |
1813 | struct ioc *ioc = rqos_to_ioc(rqos); | |
1814 | ||
1815 | blkcg_deactivate_policy(rqos->q, &blkcg_policy_iocost); | |
1816 | ||
1817 | spin_lock_irq(&ioc->lock); | |
1818 | ioc->running = IOC_STOP; | |
1819 | spin_unlock_irq(&ioc->lock); | |
1820 | ||
1821 | del_timer_sync(&ioc->timer); | |
1822 | free_percpu(ioc->pcpu_stat); | |
1823 | kfree(ioc); | |
1824 | } | |
1825 | ||
1826 | static struct rq_qos_ops ioc_rqos_ops = { | |
1827 | .throttle = ioc_rqos_throttle, | |
1828 | .merge = ioc_rqos_merge, | |
1829 | .done_bio = ioc_rqos_done_bio, | |
1830 | .done = ioc_rqos_done, | |
1831 | .queue_depth_changed = ioc_rqos_queue_depth_changed, | |
1832 | .exit = ioc_rqos_exit, | |
1833 | }; | |
1834 | ||
1835 | static int blk_iocost_init(struct request_queue *q) | |
1836 | { | |
1837 | struct ioc *ioc; | |
1838 | struct rq_qos *rqos; | |
1839 | int ret; | |
1840 | ||
1841 | ioc = kzalloc(sizeof(*ioc), GFP_KERNEL); | |
1842 | if (!ioc) | |
1843 | return -ENOMEM; | |
1844 | ||
1845 | ioc->pcpu_stat = alloc_percpu(struct ioc_pcpu_stat); | |
1846 | if (!ioc->pcpu_stat) { | |
1847 | kfree(ioc); | |
1848 | return -ENOMEM; | |
1849 | } | |
1850 | ||
1851 | rqos = &ioc->rqos; | |
1852 | rqos->id = RQ_QOS_COST; | |
1853 | rqos->ops = &ioc_rqos_ops; | |
1854 | rqos->q = q; | |
1855 | ||
1856 | spin_lock_init(&ioc->lock); | |
1857 | timer_setup(&ioc->timer, ioc_timer_fn, 0); | |
1858 | INIT_LIST_HEAD(&ioc->active_iocgs); | |
1859 | ||
1860 | ioc->running = IOC_IDLE; | |
1861 | atomic64_set(&ioc->vtime_rate, VTIME_PER_USEC); | |
1862 | seqcount_init(&ioc->period_seqcount); | |
1863 | ioc->period_at = ktime_to_us(ktime_get()); | |
1864 | atomic64_set(&ioc->cur_period, 0); | |
1865 | atomic_set(&ioc->hweight_gen, 0); | |
1866 | ||
1867 | spin_lock_irq(&ioc->lock); | |
1868 | ioc->autop_idx = AUTOP_INVALID; | |
1869 | ioc_refresh_params(ioc, true); | |
1870 | spin_unlock_irq(&ioc->lock); | |
1871 | ||
1872 | rq_qos_add(q, rqos); | |
1873 | ret = blkcg_activate_policy(q, &blkcg_policy_iocost); | |
1874 | if (ret) { | |
1875 | rq_qos_del(q, rqos); | |
1876 | kfree(ioc); | |
1877 | return ret; | |
1878 | } | |
1879 | return 0; | |
1880 | } | |
1881 | ||
1882 | static struct blkcg_policy_data *ioc_cpd_alloc(gfp_t gfp) | |
1883 | { | |
1884 | struct ioc_cgrp *iocc; | |
1885 | ||
1886 | iocc = kzalloc(sizeof(struct ioc_cgrp), gfp); | |
1887 | iocc->dfl_weight = CGROUP_WEIGHT_DFL; | |
1888 | ||
1889 | return &iocc->cpd; | |
1890 | } | |
1891 | ||
1892 | static void ioc_cpd_free(struct blkcg_policy_data *cpd) | |
1893 | { | |
1894 | kfree(container_of(cpd, struct ioc_cgrp, cpd)); | |
1895 | } | |
1896 | ||
1897 | static struct blkg_policy_data *ioc_pd_alloc(gfp_t gfp, struct request_queue *q, | |
1898 | struct blkcg *blkcg) | |
1899 | { | |
1900 | int levels = blkcg->css.cgroup->level + 1; | |
1901 | struct ioc_gq *iocg; | |
1902 | ||
1903 | iocg = kzalloc_node(sizeof(*iocg) + levels * sizeof(iocg->ancestors[0]), | |
1904 | gfp, q->node); | |
1905 | if (!iocg) | |
1906 | return NULL; | |
1907 | ||
1908 | return &iocg->pd; | |
1909 | } | |
1910 | ||
1911 | static void ioc_pd_init(struct blkg_policy_data *pd) | |
1912 | { | |
1913 | struct ioc_gq *iocg = pd_to_iocg(pd); | |
1914 | struct blkcg_gq *blkg = pd_to_blkg(&iocg->pd); | |
1915 | struct ioc *ioc = q_to_ioc(blkg->q); | |
1916 | struct ioc_now now; | |
1917 | struct blkcg_gq *tblkg; | |
1918 | unsigned long flags; | |
1919 | ||
1920 | ioc_now(ioc, &now); | |
1921 | ||
1922 | iocg->ioc = ioc; | |
1923 | atomic64_set(&iocg->vtime, now.vnow); | |
1924 | atomic64_set(&iocg->done_vtime, now.vnow); | |
1925 | atomic64_set(&iocg->active_period, atomic64_read(&ioc->cur_period)); | |
1926 | INIT_LIST_HEAD(&iocg->active_list); | |
1927 | iocg->hweight_active = HWEIGHT_WHOLE; | |
1928 | iocg->hweight_inuse = HWEIGHT_WHOLE; | |
1929 | ||
1930 | init_waitqueue_head(&iocg->waitq); | |
1931 | hrtimer_init(&iocg->waitq_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS); | |
1932 | iocg->waitq_timer.function = iocg_waitq_timer_fn; | |
1933 | hrtimer_init(&iocg->delay_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS); | |
1934 | iocg->delay_timer.function = iocg_delay_timer_fn; | |
1935 | ||
1936 | iocg->level = blkg->blkcg->css.cgroup->level; | |
1937 | ||
1938 | for (tblkg = blkg; tblkg; tblkg = tblkg->parent) { | |
1939 | struct ioc_gq *tiocg = blkg_to_iocg(tblkg); | |
1940 | iocg->ancestors[tiocg->level] = tiocg; | |
1941 | } | |
1942 | ||
1943 | spin_lock_irqsave(&ioc->lock, flags); | |
1944 | weight_updated(iocg); | |
1945 | spin_unlock_irqrestore(&ioc->lock, flags); | |
1946 | } | |
1947 | ||
1948 | static void ioc_pd_free(struct blkg_policy_data *pd) | |
1949 | { | |
1950 | struct ioc_gq *iocg = pd_to_iocg(pd); | |
1951 | struct ioc *ioc = iocg->ioc; | |
1952 | ||
1953 | if (ioc) { | |
1954 | hrtimer_cancel(&iocg->waitq_timer); | |
1955 | hrtimer_cancel(&iocg->delay_timer); | |
1956 | ||
1957 | spin_lock(&ioc->lock); | |
1958 | if (!list_empty(&iocg->active_list)) { | |
1959 | propagate_active_weight(iocg, 0, 0); | |
1960 | list_del_init(&iocg->active_list); | |
1961 | } | |
1962 | spin_unlock(&ioc->lock); | |
1963 | } | |
1964 | kfree(iocg); | |
1965 | } | |
1966 | ||
1967 | static u64 ioc_weight_prfill(struct seq_file *sf, struct blkg_policy_data *pd, | |
1968 | int off) | |
1969 | { | |
1970 | const char *dname = blkg_dev_name(pd->blkg); | |
1971 | struct ioc_gq *iocg = pd_to_iocg(pd); | |
1972 | ||
1973 | if (dname && iocg->cfg_weight) | |
1974 | seq_printf(sf, "%s %u\n", dname, iocg->cfg_weight); | |
1975 | return 0; | |
1976 | } | |
1977 | ||
1978 | ||
1979 | static int ioc_weight_show(struct seq_file *sf, void *v) | |
1980 | { | |
1981 | struct blkcg *blkcg = css_to_blkcg(seq_css(sf)); | |
1982 | struct ioc_cgrp *iocc = blkcg_to_iocc(blkcg); | |
1983 | ||
1984 | seq_printf(sf, "default %u\n", iocc->dfl_weight); | |
1985 | blkcg_print_blkgs(sf, blkcg, ioc_weight_prfill, | |
1986 | &blkcg_policy_iocost, seq_cft(sf)->private, false); | |
1987 | return 0; | |
1988 | } | |
1989 | ||
1990 | static ssize_t ioc_weight_write(struct kernfs_open_file *of, char *buf, | |
1991 | size_t nbytes, loff_t off) | |
1992 | { | |
1993 | struct blkcg *blkcg = css_to_blkcg(of_css(of)); | |
1994 | struct ioc_cgrp *iocc = blkcg_to_iocc(blkcg); | |
1995 | struct blkg_conf_ctx ctx; | |
1996 | struct ioc_gq *iocg; | |
1997 | u32 v; | |
1998 | int ret; | |
1999 | ||
2000 | if (!strchr(buf, ':')) { | |
2001 | struct blkcg_gq *blkg; | |
2002 | ||
2003 | if (!sscanf(buf, "default %u", &v) && !sscanf(buf, "%u", &v)) | |
2004 | return -EINVAL; | |
2005 | ||
2006 | if (v < CGROUP_WEIGHT_MIN || v > CGROUP_WEIGHT_MAX) | |
2007 | return -EINVAL; | |
2008 | ||
2009 | spin_lock(&blkcg->lock); | |
2010 | iocc->dfl_weight = v; | |
2011 | hlist_for_each_entry(blkg, &blkcg->blkg_list, blkcg_node) { | |
2012 | struct ioc_gq *iocg = blkg_to_iocg(blkg); | |
2013 | ||
2014 | if (iocg) { | |
2015 | spin_lock_irq(&iocg->ioc->lock); | |
2016 | weight_updated(iocg); | |
2017 | spin_unlock_irq(&iocg->ioc->lock); | |
2018 | } | |
2019 | } | |
2020 | spin_unlock(&blkcg->lock); | |
2021 | ||
2022 | return nbytes; | |
2023 | } | |
2024 | ||
2025 | ret = blkg_conf_prep(blkcg, &blkcg_policy_iocost, buf, &ctx); | |
2026 | if (ret) | |
2027 | return ret; | |
2028 | ||
2029 | iocg = blkg_to_iocg(ctx.blkg); | |
2030 | ||
2031 | if (!strncmp(ctx.body, "default", 7)) { | |
2032 | v = 0; | |
2033 | } else { | |
2034 | if (!sscanf(ctx.body, "%u", &v)) | |
2035 | goto einval; | |
2036 | if (v < CGROUP_WEIGHT_MIN || v > CGROUP_WEIGHT_MAX) | |
2037 | goto einval; | |
2038 | } | |
2039 | ||
2040 | spin_lock_irq(&iocg->ioc->lock); | |
2041 | iocg->cfg_weight = v; | |
2042 | weight_updated(iocg); | |
2043 | spin_unlock_irq(&iocg->ioc->lock); | |
2044 | ||
2045 | blkg_conf_finish(&ctx); | |
2046 | return nbytes; | |
2047 | ||
2048 | einval: | |
2049 | blkg_conf_finish(&ctx); | |
2050 | return -EINVAL; | |
2051 | } | |
2052 | ||
2053 | static u64 ioc_qos_prfill(struct seq_file *sf, struct blkg_policy_data *pd, | |
2054 | int off) | |
2055 | { | |
2056 | const char *dname = blkg_dev_name(pd->blkg); | |
2057 | struct ioc *ioc = pd_to_iocg(pd)->ioc; | |
2058 | ||
2059 | if (!dname) | |
2060 | return 0; | |
2061 | ||
2062 | seq_printf(sf, "%s enable=%d ctrl=%s rpct=%u.%02u rlat=%u wpct=%u.%02u wlat=%u min=%u.%02u max=%u.%02u\n", | |
2063 | dname, ioc->enabled, ioc->user_qos_params ? "user" : "auto", | |
2064 | ioc->params.qos[QOS_RPPM] / 10000, | |
2065 | ioc->params.qos[QOS_RPPM] % 10000 / 100, | |
2066 | ioc->params.qos[QOS_RLAT], | |
2067 | ioc->params.qos[QOS_WPPM] / 10000, | |
2068 | ioc->params.qos[QOS_WPPM] % 10000 / 100, | |
2069 | ioc->params.qos[QOS_WLAT], | |
2070 | ioc->params.qos[QOS_MIN] / 10000, | |
2071 | ioc->params.qos[QOS_MIN] % 10000 / 100, | |
2072 | ioc->params.qos[QOS_MAX] / 10000, | |
2073 | ioc->params.qos[QOS_MAX] % 10000 / 100); | |
2074 | return 0; | |
2075 | } | |
2076 | ||
2077 | static int ioc_qos_show(struct seq_file *sf, void *v) | |
2078 | { | |
2079 | struct blkcg *blkcg = css_to_blkcg(seq_css(sf)); | |
2080 | ||
2081 | blkcg_print_blkgs(sf, blkcg, ioc_qos_prfill, | |
2082 | &blkcg_policy_iocost, seq_cft(sf)->private, false); | |
2083 | return 0; | |
2084 | } | |
2085 | ||
2086 | static const match_table_t qos_ctrl_tokens = { | |
2087 | { QOS_ENABLE, "enable=%u" }, | |
2088 | { QOS_CTRL, "ctrl=%s" }, | |
2089 | { NR_QOS_CTRL_PARAMS, NULL }, | |
2090 | }; | |
2091 | ||
2092 | static const match_table_t qos_tokens = { | |
2093 | { QOS_RPPM, "rpct=%s" }, | |
2094 | { QOS_RLAT, "rlat=%u" }, | |
2095 | { QOS_WPPM, "wpct=%s" }, | |
2096 | { QOS_WLAT, "wlat=%u" }, | |
2097 | { QOS_MIN, "min=%s" }, | |
2098 | { QOS_MAX, "max=%s" }, | |
2099 | { NR_QOS_PARAMS, NULL }, | |
2100 | }; | |
2101 | ||
2102 | static ssize_t ioc_qos_write(struct kernfs_open_file *of, char *input, | |
2103 | size_t nbytes, loff_t off) | |
2104 | { | |
2105 | struct gendisk *disk; | |
2106 | struct ioc *ioc; | |
2107 | u32 qos[NR_QOS_PARAMS]; | |
2108 | bool enable, user; | |
2109 | char *p; | |
2110 | int ret; | |
2111 | ||
2112 | disk = blkcg_conf_get_disk(&input); | |
2113 | if (IS_ERR(disk)) | |
2114 | return PTR_ERR(disk); | |
2115 | ||
2116 | ioc = q_to_ioc(disk->queue); | |
2117 | if (!ioc) { | |
2118 | ret = blk_iocost_init(disk->queue); | |
2119 | if (ret) | |
2120 | goto err; | |
2121 | ioc = q_to_ioc(disk->queue); | |
2122 | } | |
2123 | ||
2124 | spin_lock_irq(&ioc->lock); | |
2125 | memcpy(qos, ioc->params.qos, sizeof(qos)); | |
2126 | enable = ioc->enabled; | |
2127 | user = ioc->user_qos_params; | |
2128 | spin_unlock_irq(&ioc->lock); | |
2129 | ||
2130 | while ((p = strsep(&input, " \t\n"))) { | |
2131 | substring_t args[MAX_OPT_ARGS]; | |
2132 | char buf[32]; | |
2133 | int tok; | |
2134 | s64 v; | |
2135 | ||
2136 | if (!*p) | |
2137 | continue; | |
2138 | ||
2139 | switch (match_token(p, qos_ctrl_tokens, args)) { | |
2140 | case QOS_ENABLE: | |
2141 | match_u64(&args[0], &v); | |
2142 | enable = v; | |
2143 | continue; | |
2144 | case QOS_CTRL: | |
2145 | match_strlcpy(buf, &args[0], sizeof(buf)); | |
2146 | if (!strcmp(buf, "auto")) | |
2147 | user = false; | |
2148 | else if (!strcmp(buf, "user")) | |
2149 | user = true; | |
2150 | else | |
2151 | goto einval; | |
2152 | continue; | |
2153 | } | |
2154 | ||
2155 | tok = match_token(p, qos_tokens, args); | |
2156 | switch (tok) { | |
2157 | case QOS_RPPM: | |
2158 | case QOS_WPPM: | |
2159 | if (match_strlcpy(buf, &args[0], sizeof(buf)) >= | |
2160 | sizeof(buf)) | |
2161 | goto einval; | |
2162 | if (cgroup_parse_float(buf, 2, &v)) | |
2163 | goto einval; | |
2164 | if (v < 0 || v > 10000) | |
2165 | goto einval; | |
2166 | qos[tok] = v * 100; | |
2167 | break; | |
2168 | case QOS_RLAT: | |
2169 | case QOS_WLAT: | |
2170 | if (match_u64(&args[0], &v)) | |
2171 | goto einval; | |
2172 | qos[tok] = v; | |
2173 | break; | |
2174 | case QOS_MIN: | |
2175 | case QOS_MAX: | |
2176 | if (match_strlcpy(buf, &args[0], sizeof(buf)) >= | |
2177 | sizeof(buf)) | |
2178 | goto einval; | |
2179 | if (cgroup_parse_float(buf, 2, &v)) | |
2180 | goto einval; | |
2181 | if (v < 0) | |
2182 | goto einval; | |
2183 | qos[tok] = clamp_t(s64, v * 100, | |
2184 | VRATE_MIN_PPM, VRATE_MAX_PPM); | |
2185 | break; | |
2186 | default: | |
2187 | goto einval; | |
2188 | } | |
2189 | user = true; | |
2190 | } | |
2191 | ||
2192 | if (qos[QOS_MIN] > qos[QOS_MAX]) | |
2193 | goto einval; | |
2194 | ||
2195 | spin_lock_irq(&ioc->lock); | |
2196 | ||
2197 | if (enable) { | |
2198 | blk_queue_flag_set(QUEUE_FLAG_RQ_ALLOC_TIME, ioc->rqos.q); | |
2199 | ioc->enabled = true; | |
2200 | } else { | |
2201 | blk_queue_flag_clear(QUEUE_FLAG_RQ_ALLOC_TIME, ioc->rqos.q); | |
2202 | ioc->enabled = false; | |
2203 | } | |
2204 | ||
2205 | if (user) { | |
2206 | memcpy(ioc->params.qos, qos, sizeof(qos)); | |
2207 | ioc->user_qos_params = true; | |
2208 | } else { | |
2209 | ioc->user_qos_params = false; | |
2210 | } | |
2211 | ||
2212 | ioc_refresh_params(ioc, true); | |
2213 | spin_unlock_irq(&ioc->lock); | |
2214 | ||
2215 | put_disk_and_module(disk); | |
2216 | return nbytes; | |
2217 | einval: | |
2218 | ret = -EINVAL; | |
2219 | err: | |
2220 | put_disk_and_module(disk); | |
2221 | return ret; | |
2222 | } | |
2223 | ||
2224 | static u64 ioc_cost_model_prfill(struct seq_file *sf, | |
2225 | struct blkg_policy_data *pd, int off) | |
2226 | { | |
2227 | const char *dname = blkg_dev_name(pd->blkg); | |
2228 | struct ioc *ioc = pd_to_iocg(pd)->ioc; | |
2229 | u64 *u = ioc->params.i_lcoefs; | |
2230 | ||
2231 | if (!dname) | |
2232 | return 0; | |
2233 | ||
2234 | seq_printf(sf, "%s ctrl=%s model=linear " | |
2235 | "rbps=%llu rseqiops=%llu rrandiops=%llu " | |
2236 | "wbps=%llu wseqiops=%llu wrandiops=%llu\n", | |
2237 | dname, ioc->user_cost_model ? "user" : "auto", | |
2238 | u[I_LCOEF_RBPS], u[I_LCOEF_RSEQIOPS], u[I_LCOEF_RRANDIOPS], | |
2239 | u[I_LCOEF_WBPS], u[I_LCOEF_WSEQIOPS], u[I_LCOEF_WRANDIOPS]); | |
2240 | return 0; | |
2241 | } | |
2242 | ||
2243 | static int ioc_cost_model_show(struct seq_file *sf, void *v) | |
2244 | { | |
2245 | struct blkcg *blkcg = css_to_blkcg(seq_css(sf)); | |
2246 | ||
2247 | blkcg_print_blkgs(sf, blkcg, ioc_cost_model_prfill, | |
2248 | &blkcg_policy_iocost, seq_cft(sf)->private, false); | |
2249 | return 0; | |
2250 | } | |
2251 | ||
2252 | static const match_table_t cost_ctrl_tokens = { | |
2253 | { COST_CTRL, "ctrl=%s" }, | |
2254 | { COST_MODEL, "model=%s" }, | |
2255 | { NR_COST_CTRL_PARAMS, NULL }, | |
2256 | }; | |
2257 | ||
2258 | static const match_table_t i_lcoef_tokens = { | |
2259 | { I_LCOEF_RBPS, "rbps=%u" }, | |
2260 | { I_LCOEF_RSEQIOPS, "rseqiops=%u" }, | |
2261 | { I_LCOEF_RRANDIOPS, "rrandiops=%u" }, | |
2262 | { I_LCOEF_WBPS, "wbps=%u" }, | |
2263 | { I_LCOEF_WSEQIOPS, "wseqiops=%u" }, | |
2264 | { I_LCOEF_WRANDIOPS, "wrandiops=%u" }, | |
2265 | { NR_I_LCOEFS, NULL }, | |
2266 | }; | |
2267 | ||
2268 | static ssize_t ioc_cost_model_write(struct kernfs_open_file *of, char *input, | |
2269 | size_t nbytes, loff_t off) | |
2270 | { | |
2271 | struct gendisk *disk; | |
2272 | struct ioc *ioc; | |
2273 | u64 u[NR_I_LCOEFS]; | |
2274 | bool user; | |
2275 | char *p; | |
2276 | int ret; | |
2277 | ||
2278 | disk = blkcg_conf_get_disk(&input); | |
2279 | if (IS_ERR(disk)) | |
2280 | return PTR_ERR(disk); | |
2281 | ||
2282 | ioc = q_to_ioc(disk->queue); | |
2283 | if (!ioc) { | |
2284 | ret = blk_iocost_init(disk->queue); | |
2285 | if (ret) | |
2286 | goto err; | |
2287 | ioc = q_to_ioc(disk->queue); | |
2288 | } | |
2289 | ||
2290 | spin_lock_irq(&ioc->lock); | |
2291 | memcpy(u, ioc->params.i_lcoefs, sizeof(u)); | |
2292 | user = ioc->user_cost_model; | |
2293 | spin_unlock_irq(&ioc->lock); | |
2294 | ||
2295 | while ((p = strsep(&input, " \t\n"))) { | |
2296 | substring_t args[MAX_OPT_ARGS]; | |
2297 | char buf[32]; | |
2298 | int tok; | |
2299 | u64 v; | |
2300 | ||
2301 | if (!*p) | |
2302 | continue; | |
2303 | ||
2304 | switch (match_token(p, cost_ctrl_tokens, args)) { | |
2305 | case COST_CTRL: | |
2306 | match_strlcpy(buf, &args[0], sizeof(buf)); | |
2307 | if (!strcmp(buf, "auto")) | |
2308 | user = false; | |
2309 | else if (!strcmp(buf, "user")) | |
2310 | user = true; | |
2311 | else | |
2312 | goto einval; | |
2313 | continue; | |
2314 | case COST_MODEL: | |
2315 | match_strlcpy(buf, &args[0], sizeof(buf)); | |
2316 | if (strcmp(buf, "linear")) | |
2317 | goto einval; | |
2318 | continue; | |
2319 | } | |
2320 | ||
2321 | tok = match_token(p, i_lcoef_tokens, args); | |
2322 | if (tok == NR_I_LCOEFS) | |
2323 | goto einval; | |
2324 | if (match_u64(&args[0], &v)) | |
2325 | goto einval; | |
2326 | u[tok] = v; | |
2327 | user = true; | |
2328 | } | |
2329 | ||
2330 | spin_lock_irq(&ioc->lock); | |
2331 | if (user) { | |
2332 | memcpy(ioc->params.i_lcoefs, u, sizeof(u)); | |
2333 | ioc->user_cost_model = true; | |
2334 | } else { | |
2335 | ioc->user_cost_model = false; | |
2336 | } | |
2337 | ioc_refresh_params(ioc, true); | |
2338 | spin_unlock_irq(&ioc->lock); | |
2339 | ||
2340 | put_disk_and_module(disk); | |
2341 | return nbytes; | |
2342 | ||
2343 | einval: | |
2344 | ret = -EINVAL; | |
2345 | err: | |
2346 | put_disk_and_module(disk); | |
2347 | return ret; | |
2348 | } | |
2349 | ||
2350 | static struct cftype ioc_files[] = { | |
2351 | { | |
2352 | .name = "weight", | |
2353 | .flags = CFTYPE_NOT_ON_ROOT, | |
2354 | .seq_show = ioc_weight_show, | |
2355 | .write = ioc_weight_write, | |
2356 | }, | |
2357 | { | |
2358 | .name = "cost.qos", | |
2359 | .flags = CFTYPE_ONLY_ON_ROOT, | |
2360 | .seq_show = ioc_qos_show, | |
2361 | .write = ioc_qos_write, | |
2362 | }, | |
2363 | { | |
2364 | .name = "cost.model", | |
2365 | .flags = CFTYPE_ONLY_ON_ROOT, | |
2366 | .seq_show = ioc_cost_model_show, | |
2367 | .write = ioc_cost_model_write, | |
2368 | }, | |
2369 | {} | |
2370 | }; | |
2371 | ||
2372 | static struct blkcg_policy blkcg_policy_iocost = { | |
2373 | .dfl_cftypes = ioc_files, | |
2374 | .cpd_alloc_fn = ioc_cpd_alloc, | |
2375 | .cpd_free_fn = ioc_cpd_free, | |
2376 | .pd_alloc_fn = ioc_pd_alloc, | |
2377 | .pd_init_fn = ioc_pd_init, | |
2378 | .pd_free_fn = ioc_pd_free, | |
2379 | }; | |
2380 | ||
2381 | static int __init ioc_init(void) | |
2382 | { | |
2383 | return blkcg_policy_register(&blkcg_policy_iocost); | |
2384 | } | |
2385 | ||
2386 | static void __exit ioc_exit(void) | |
2387 | { | |
2388 | return blkcg_policy_unregister(&blkcg_policy_iocost); | |
2389 | } | |
2390 | ||
2391 | module_init(ioc_init); | |
2392 | module_exit(ioc_exit); |