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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% | |
7c1ee704 TH |
161 | * active weight hweight% inflt% dbt delay usages% |
162 | * test/a * 50/ 50 33.33/ 33.33 27.65 2 0*041 033:033:033 | |
163 | * test/b * 100/ 100 66.67/ 66.67 17.56 0 0*000 066:079:077 | |
6954ff18 TH |
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; | |
0b80f986 | 469 | u64 abs_vdebt; |
7caa4715 TH |
470 | u64 last_vtime; |
471 | ||
472 | /* | |
473 | * The period this iocg was last active in. Used for deactivation | |
474 | * and invalidating `vtime`. | |
475 | */ | |
476 | atomic64_t active_period; | |
477 | struct list_head active_list; | |
478 | ||
479 | /* see __propagate_active_weight() and current_hweight() for details */ | |
480 | u64 child_active_sum; | |
481 | u64 child_inuse_sum; | |
482 | int hweight_gen; | |
483 | u32 hweight_active; | |
484 | u32 hweight_inuse; | |
485 | bool has_surplus; | |
486 | ||
487 | struct wait_queue_head waitq; | |
488 | struct hrtimer waitq_timer; | |
489 | struct hrtimer delay_timer; | |
490 | ||
491 | /* usage is recorded as fractions of HWEIGHT_WHOLE */ | |
492 | int usage_idx; | |
493 | u32 usages[NR_USAGE_SLOTS]; | |
494 | ||
495 | /* this iocg's depth in the hierarchy and ancestors including self */ | |
496 | int level; | |
497 | struct ioc_gq *ancestors[]; | |
498 | }; | |
499 | ||
500 | /* per cgroup */ | |
501 | struct ioc_cgrp { | |
502 | struct blkcg_policy_data cpd; | |
503 | unsigned int dfl_weight; | |
504 | }; | |
505 | ||
506 | struct ioc_now { | |
507 | u64 now_ns; | |
508 | u32 now; | |
509 | u64 vnow; | |
510 | u64 vrate; | |
511 | }; | |
512 | ||
513 | struct iocg_wait { | |
514 | struct wait_queue_entry wait; | |
515 | struct bio *bio; | |
516 | u64 abs_cost; | |
517 | bool committed; | |
518 | }; | |
519 | ||
520 | struct iocg_wake_ctx { | |
521 | struct ioc_gq *iocg; | |
522 | u32 hw_inuse; | |
523 | s64 vbudget; | |
524 | }; | |
525 | ||
526 | static const struct ioc_params autop[] = { | |
527 | [AUTOP_HDD] = { | |
528 | .qos = { | |
7afcccaf TH |
529 | [QOS_RLAT] = 250000, /* 250ms */ |
530 | [QOS_WLAT] = 250000, | |
7caa4715 TH |
531 | [QOS_MIN] = VRATE_MIN_PPM, |
532 | [QOS_MAX] = VRATE_MAX_PPM, | |
533 | }, | |
534 | .i_lcoefs = { | |
535 | [I_LCOEF_RBPS] = 174019176, | |
536 | [I_LCOEF_RSEQIOPS] = 41708, | |
537 | [I_LCOEF_RRANDIOPS] = 370, | |
538 | [I_LCOEF_WBPS] = 178075866, | |
539 | [I_LCOEF_WSEQIOPS] = 42705, | |
540 | [I_LCOEF_WRANDIOPS] = 378, | |
541 | }, | |
542 | }, | |
543 | [AUTOP_SSD_QD1] = { | |
544 | .qos = { | |
545 | [QOS_RLAT] = 25000, /* 25ms */ | |
546 | [QOS_WLAT] = 25000, | |
547 | [QOS_MIN] = VRATE_MIN_PPM, | |
548 | [QOS_MAX] = VRATE_MAX_PPM, | |
549 | }, | |
550 | .i_lcoefs = { | |
551 | [I_LCOEF_RBPS] = 245855193, | |
552 | [I_LCOEF_RSEQIOPS] = 61575, | |
553 | [I_LCOEF_RRANDIOPS] = 6946, | |
554 | [I_LCOEF_WBPS] = 141365009, | |
555 | [I_LCOEF_WSEQIOPS] = 33716, | |
556 | [I_LCOEF_WRANDIOPS] = 26796, | |
557 | }, | |
558 | }, | |
559 | [AUTOP_SSD_DFL] = { | |
560 | .qos = { | |
561 | [QOS_RLAT] = 25000, /* 25ms */ | |
562 | [QOS_WLAT] = 25000, | |
563 | [QOS_MIN] = VRATE_MIN_PPM, | |
564 | [QOS_MAX] = VRATE_MAX_PPM, | |
565 | }, | |
566 | .i_lcoefs = { | |
567 | [I_LCOEF_RBPS] = 488636629, | |
568 | [I_LCOEF_RSEQIOPS] = 8932, | |
569 | [I_LCOEF_RRANDIOPS] = 8518, | |
570 | [I_LCOEF_WBPS] = 427891549, | |
571 | [I_LCOEF_WSEQIOPS] = 28755, | |
572 | [I_LCOEF_WRANDIOPS] = 21940, | |
573 | }, | |
574 | .too_fast_vrate_pct = 500, | |
575 | }, | |
576 | [AUTOP_SSD_FAST] = { | |
577 | .qos = { | |
578 | [QOS_RLAT] = 5000, /* 5ms */ | |
579 | [QOS_WLAT] = 5000, | |
580 | [QOS_MIN] = VRATE_MIN_PPM, | |
581 | [QOS_MAX] = VRATE_MAX_PPM, | |
582 | }, | |
583 | .i_lcoefs = { | |
584 | [I_LCOEF_RBPS] = 3102524156LLU, | |
585 | [I_LCOEF_RSEQIOPS] = 724816, | |
586 | [I_LCOEF_RRANDIOPS] = 778122, | |
587 | [I_LCOEF_WBPS] = 1742780862LLU, | |
588 | [I_LCOEF_WSEQIOPS] = 425702, | |
589 | [I_LCOEF_WRANDIOPS] = 443193, | |
590 | }, | |
591 | .too_slow_vrate_pct = 10, | |
592 | }, | |
593 | }; | |
594 | ||
595 | /* | |
596 | * vrate adjust percentages indexed by ioc->busy_level. We adjust up on | |
597 | * vtime credit shortage and down on device saturation. | |
598 | */ | |
599 | static u32 vrate_adj_pct[] = | |
600 | { 0, 0, 0, 0, | |
601 | 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, | |
602 | 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, | |
603 | 4, 4, 4, 4, 4, 4, 4, 4, 8, 8, 8, 8, 8, 8, 8, 8, 16 }; | |
604 | ||
605 | static struct blkcg_policy blkcg_policy_iocost; | |
606 | ||
607 | /* accessors and helpers */ | |
608 | static struct ioc *rqos_to_ioc(struct rq_qos *rqos) | |
609 | { | |
610 | return container_of(rqos, struct ioc, rqos); | |
611 | } | |
612 | ||
613 | static struct ioc *q_to_ioc(struct request_queue *q) | |
614 | { | |
615 | return rqos_to_ioc(rq_qos_id(q, RQ_QOS_COST)); | |
616 | } | |
617 | ||
618 | static const char *q_name(struct request_queue *q) | |
619 | { | |
620 | if (test_bit(QUEUE_FLAG_REGISTERED, &q->queue_flags)) | |
621 | return kobject_name(q->kobj.parent); | |
622 | else | |
623 | return "<unknown>"; | |
624 | } | |
625 | ||
626 | static const char __maybe_unused *ioc_name(struct ioc *ioc) | |
627 | { | |
628 | return q_name(ioc->rqos.q); | |
629 | } | |
630 | ||
631 | static struct ioc_gq *pd_to_iocg(struct blkg_policy_data *pd) | |
632 | { | |
633 | return pd ? container_of(pd, struct ioc_gq, pd) : NULL; | |
634 | } | |
635 | ||
636 | static struct ioc_gq *blkg_to_iocg(struct blkcg_gq *blkg) | |
637 | { | |
638 | return pd_to_iocg(blkg_to_pd(blkg, &blkcg_policy_iocost)); | |
639 | } | |
640 | ||
641 | static struct blkcg_gq *iocg_to_blkg(struct ioc_gq *iocg) | |
642 | { | |
643 | return pd_to_blkg(&iocg->pd); | |
644 | } | |
645 | ||
646 | static struct ioc_cgrp *blkcg_to_iocc(struct blkcg *blkcg) | |
647 | { | |
648 | return container_of(blkcg_to_cpd(blkcg, &blkcg_policy_iocost), | |
649 | struct ioc_cgrp, cpd); | |
650 | } | |
651 | ||
652 | /* | |
653 | * Scale @abs_cost to the inverse of @hw_inuse. The lower the hierarchical | |
36a52481 | 654 | * weight, the more expensive each IO. Must round up. |
7caa4715 TH |
655 | */ |
656 | static u64 abs_cost_to_cost(u64 abs_cost, u32 hw_inuse) | |
657 | { | |
658 | return DIV64_U64_ROUND_UP(abs_cost * HWEIGHT_WHOLE, hw_inuse); | |
659 | } | |
660 | ||
36a52481 TH |
661 | /* |
662 | * The inverse of abs_cost_to_cost(). Must round up. | |
663 | */ | |
664 | static u64 cost_to_abs_cost(u64 cost, u32 hw_inuse) | |
665 | { | |
666 | return DIV64_U64_ROUND_UP(cost * hw_inuse, HWEIGHT_WHOLE); | |
667 | } | |
668 | ||
7caa4715 TH |
669 | static void iocg_commit_bio(struct ioc_gq *iocg, struct bio *bio, u64 cost) |
670 | { | |
671 | bio->bi_iocost_cost = cost; | |
672 | atomic64_add(cost, &iocg->vtime); | |
673 | } | |
674 | ||
675 | #define CREATE_TRACE_POINTS | |
676 | #include <trace/events/iocost.h> | |
677 | ||
678 | /* latency Qos params changed, update period_us and all the dependent params */ | |
679 | static void ioc_refresh_period_us(struct ioc *ioc) | |
680 | { | |
681 | u32 ppm, lat, multi, period_us; | |
682 | ||
683 | lockdep_assert_held(&ioc->lock); | |
684 | ||
685 | /* pick the higher latency target */ | |
686 | if (ioc->params.qos[QOS_RLAT] >= ioc->params.qos[QOS_WLAT]) { | |
687 | ppm = ioc->params.qos[QOS_RPPM]; | |
688 | lat = ioc->params.qos[QOS_RLAT]; | |
689 | } else { | |
690 | ppm = ioc->params.qos[QOS_WPPM]; | |
691 | lat = ioc->params.qos[QOS_WLAT]; | |
692 | } | |
693 | ||
694 | /* | |
695 | * We want the period to be long enough to contain a healthy number | |
696 | * of IOs while short enough for granular control. Define it as a | |
697 | * multiple of the latency target. Ideally, the multiplier should | |
698 | * be scaled according to the percentile so that it would nominally | |
699 | * contain a certain number of requests. Let's be simpler and | |
700 | * scale it linearly so that it's 2x >= pct(90) and 10x at pct(50). | |
701 | */ | |
702 | if (ppm) | |
703 | multi = max_t(u32, (MILLION - ppm) / 50000, 2); | |
704 | else | |
705 | multi = 2; | |
706 | period_us = multi * lat; | |
707 | period_us = clamp_t(u32, period_us, MIN_PERIOD, MAX_PERIOD); | |
708 | ||
709 | /* calculate dependent params */ | |
710 | ioc->period_us = period_us; | |
711 | ioc->margin_us = period_us * MARGIN_PCT / 100; | |
712 | ioc->inuse_margin_vtime = DIV64_U64_ROUND_UP( | |
713 | period_us * VTIME_PER_USEC * INUSE_MARGIN_PCT, 100); | |
714 | } | |
715 | ||
716 | static int ioc_autop_idx(struct ioc *ioc) | |
717 | { | |
718 | int idx = ioc->autop_idx; | |
719 | const struct ioc_params *p = &autop[idx]; | |
720 | u32 vrate_pct; | |
721 | u64 now_ns; | |
722 | ||
723 | /* rotational? */ | |
724 | if (!blk_queue_nonrot(ioc->rqos.q)) | |
725 | return AUTOP_HDD; | |
726 | ||
727 | /* handle SATA SSDs w/ broken NCQ */ | |
728 | if (blk_queue_depth(ioc->rqos.q) == 1) | |
729 | return AUTOP_SSD_QD1; | |
730 | ||
731 | /* use one of the normal ssd sets */ | |
732 | if (idx < AUTOP_SSD_DFL) | |
733 | return AUTOP_SSD_DFL; | |
734 | ||
735 | /* if user is overriding anything, maintain what was there */ | |
736 | if (ioc->user_qos_params || ioc->user_cost_model) | |
737 | return idx; | |
738 | ||
739 | /* step up/down based on the vrate */ | |
740 | vrate_pct = div64_u64(atomic64_read(&ioc->vtime_rate) * 100, | |
741 | VTIME_PER_USEC); | |
742 | now_ns = ktime_get_ns(); | |
743 | ||
744 | if (p->too_fast_vrate_pct && p->too_fast_vrate_pct <= vrate_pct) { | |
745 | if (!ioc->autop_too_fast_at) | |
746 | ioc->autop_too_fast_at = now_ns; | |
747 | if (now_ns - ioc->autop_too_fast_at >= AUTOP_CYCLE_NSEC) | |
748 | return idx + 1; | |
749 | } else { | |
750 | ioc->autop_too_fast_at = 0; | |
751 | } | |
752 | ||
753 | if (p->too_slow_vrate_pct && p->too_slow_vrate_pct >= vrate_pct) { | |
754 | if (!ioc->autop_too_slow_at) | |
755 | ioc->autop_too_slow_at = now_ns; | |
756 | if (now_ns - ioc->autop_too_slow_at >= AUTOP_CYCLE_NSEC) | |
757 | return idx - 1; | |
758 | } else { | |
759 | ioc->autop_too_slow_at = 0; | |
760 | } | |
761 | ||
762 | return idx; | |
763 | } | |
764 | ||
765 | /* | |
766 | * Take the followings as input | |
767 | * | |
768 | * @bps maximum sequential throughput | |
769 | * @seqiops maximum sequential 4k iops | |
770 | * @randiops maximum random 4k iops | |
771 | * | |
772 | * and calculate the linear model cost coefficients. | |
773 | * | |
774 | * *@page per-page cost 1s / (@bps / 4096) | |
775 | * *@seqio base cost of a seq IO max((1s / @seqiops) - *@page, 0) | |
776 | * @randiops base cost of a rand IO max((1s / @randiops) - *@page, 0) | |
777 | */ | |
778 | static void calc_lcoefs(u64 bps, u64 seqiops, u64 randiops, | |
779 | u64 *page, u64 *seqio, u64 *randio) | |
780 | { | |
781 | u64 v; | |
782 | ||
783 | *page = *seqio = *randio = 0; | |
784 | ||
785 | if (bps) | |
786 | *page = DIV64_U64_ROUND_UP(VTIME_PER_SEC, | |
787 | DIV_ROUND_UP_ULL(bps, IOC_PAGE_SIZE)); | |
788 | ||
789 | if (seqiops) { | |
790 | v = DIV64_U64_ROUND_UP(VTIME_PER_SEC, seqiops); | |
791 | if (v > *page) | |
792 | *seqio = v - *page; | |
793 | } | |
794 | ||
795 | if (randiops) { | |
796 | v = DIV64_U64_ROUND_UP(VTIME_PER_SEC, randiops); | |
797 | if (v > *page) | |
798 | *randio = v - *page; | |
799 | } | |
800 | } | |
801 | ||
802 | static void ioc_refresh_lcoefs(struct ioc *ioc) | |
803 | { | |
804 | u64 *u = ioc->params.i_lcoefs; | |
805 | u64 *c = ioc->params.lcoefs; | |
806 | ||
807 | calc_lcoefs(u[I_LCOEF_RBPS], u[I_LCOEF_RSEQIOPS], u[I_LCOEF_RRANDIOPS], | |
808 | &c[LCOEF_RPAGE], &c[LCOEF_RSEQIO], &c[LCOEF_RRANDIO]); | |
809 | calc_lcoefs(u[I_LCOEF_WBPS], u[I_LCOEF_WSEQIOPS], u[I_LCOEF_WRANDIOPS], | |
810 | &c[LCOEF_WPAGE], &c[LCOEF_WSEQIO], &c[LCOEF_WRANDIO]); | |
811 | } | |
812 | ||
813 | static bool ioc_refresh_params(struct ioc *ioc, bool force) | |
814 | { | |
815 | const struct ioc_params *p; | |
816 | int idx; | |
817 | ||
818 | lockdep_assert_held(&ioc->lock); | |
819 | ||
820 | idx = ioc_autop_idx(ioc); | |
821 | p = &autop[idx]; | |
822 | ||
823 | if (idx == ioc->autop_idx && !force) | |
824 | return false; | |
825 | ||
826 | if (idx != ioc->autop_idx) | |
827 | atomic64_set(&ioc->vtime_rate, VTIME_PER_USEC); | |
828 | ||
829 | ioc->autop_idx = idx; | |
830 | ioc->autop_too_fast_at = 0; | |
831 | ioc->autop_too_slow_at = 0; | |
832 | ||
833 | if (!ioc->user_qos_params) | |
834 | memcpy(ioc->params.qos, p->qos, sizeof(p->qos)); | |
835 | if (!ioc->user_cost_model) | |
836 | memcpy(ioc->params.i_lcoefs, p->i_lcoefs, sizeof(p->i_lcoefs)); | |
837 | ||
838 | ioc_refresh_period_us(ioc); | |
839 | ioc_refresh_lcoefs(ioc); | |
840 | ||
841 | ioc->vrate_min = DIV64_U64_ROUND_UP((u64)ioc->params.qos[QOS_MIN] * | |
842 | VTIME_PER_USEC, MILLION); | |
843 | ioc->vrate_max = div64_u64((u64)ioc->params.qos[QOS_MAX] * | |
844 | VTIME_PER_USEC, MILLION); | |
845 | ||
846 | return true; | |
847 | } | |
848 | ||
849 | /* take a snapshot of the current [v]time and vrate */ | |
850 | static void ioc_now(struct ioc *ioc, struct ioc_now *now) | |
851 | { | |
852 | unsigned seq; | |
853 | ||
854 | now->now_ns = ktime_get(); | |
855 | now->now = ktime_to_us(now->now_ns); | |
856 | now->vrate = atomic64_read(&ioc->vtime_rate); | |
857 | ||
858 | /* | |
859 | * The current vtime is | |
860 | * | |
861 | * vtime at period start + (wallclock time since the start) * vrate | |
862 | * | |
863 | * As a consistent snapshot of `period_at_vtime` and `period_at` is | |
864 | * needed, they're seqcount protected. | |
865 | */ | |
866 | do { | |
867 | seq = read_seqcount_begin(&ioc->period_seqcount); | |
868 | now->vnow = ioc->period_at_vtime + | |
869 | (now->now - ioc->period_at) * now->vrate; | |
870 | } while (read_seqcount_retry(&ioc->period_seqcount, seq)); | |
871 | } | |
872 | ||
873 | static void ioc_start_period(struct ioc *ioc, struct ioc_now *now) | |
874 | { | |
875 | lockdep_assert_held(&ioc->lock); | |
876 | WARN_ON_ONCE(ioc->running != IOC_RUNNING); | |
877 | ||
878 | write_seqcount_begin(&ioc->period_seqcount); | |
879 | ioc->period_at = now->now; | |
880 | ioc->period_at_vtime = now->vnow; | |
881 | write_seqcount_end(&ioc->period_seqcount); | |
882 | ||
883 | ioc->timer.expires = jiffies + usecs_to_jiffies(ioc->period_us); | |
884 | add_timer(&ioc->timer); | |
885 | } | |
886 | ||
887 | /* | |
888 | * Update @iocg's `active` and `inuse` to @active and @inuse, update level | |
889 | * weight sums and propagate upwards accordingly. | |
890 | */ | |
891 | static void __propagate_active_weight(struct ioc_gq *iocg, u32 active, u32 inuse) | |
892 | { | |
893 | struct ioc *ioc = iocg->ioc; | |
894 | int lvl; | |
895 | ||
896 | lockdep_assert_held(&ioc->lock); | |
897 | ||
898 | inuse = min(active, inuse); | |
899 | ||
900 | for (lvl = iocg->level - 1; lvl >= 0; lvl--) { | |
901 | struct ioc_gq *parent = iocg->ancestors[lvl]; | |
902 | struct ioc_gq *child = iocg->ancestors[lvl + 1]; | |
903 | u32 parent_active = 0, parent_inuse = 0; | |
904 | ||
905 | /* update the level sums */ | |
906 | parent->child_active_sum += (s32)(active - child->active); | |
907 | parent->child_inuse_sum += (s32)(inuse - child->inuse); | |
908 | /* apply the udpates */ | |
909 | child->active = active; | |
910 | child->inuse = inuse; | |
911 | ||
912 | /* | |
913 | * The delta between inuse and active sums indicates that | |
914 | * that much of weight is being given away. Parent's inuse | |
915 | * and active should reflect the ratio. | |
916 | */ | |
917 | if (parent->child_active_sum) { | |
918 | parent_active = parent->weight; | |
919 | parent_inuse = DIV64_U64_ROUND_UP( | |
920 | parent_active * parent->child_inuse_sum, | |
921 | parent->child_active_sum); | |
922 | } | |
923 | ||
924 | /* do we need to keep walking up? */ | |
925 | if (parent_active == parent->active && | |
926 | parent_inuse == parent->inuse) | |
927 | break; | |
928 | ||
929 | active = parent_active; | |
930 | inuse = parent_inuse; | |
931 | } | |
932 | ||
933 | ioc->weights_updated = true; | |
934 | } | |
935 | ||
936 | static void commit_active_weights(struct ioc *ioc) | |
937 | { | |
938 | lockdep_assert_held(&ioc->lock); | |
939 | ||
940 | if (ioc->weights_updated) { | |
941 | /* paired with rmb in current_hweight(), see there */ | |
942 | smp_wmb(); | |
943 | atomic_inc(&ioc->hweight_gen); | |
944 | ioc->weights_updated = false; | |
945 | } | |
946 | } | |
947 | ||
948 | static void propagate_active_weight(struct ioc_gq *iocg, u32 active, u32 inuse) | |
949 | { | |
950 | __propagate_active_weight(iocg, active, inuse); | |
951 | commit_active_weights(iocg->ioc); | |
952 | } | |
953 | ||
954 | static void current_hweight(struct ioc_gq *iocg, u32 *hw_activep, u32 *hw_inusep) | |
955 | { | |
956 | struct ioc *ioc = iocg->ioc; | |
957 | int lvl; | |
958 | u32 hwa, hwi; | |
959 | int ioc_gen; | |
960 | ||
961 | /* hot path - if uptodate, use cached */ | |
962 | ioc_gen = atomic_read(&ioc->hweight_gen); | |
963 | if (ioc_gen == iocg->hweight_gen) | |
964 | goto out; | |
965 | ||
966 | /* | |
967 | * Paired with wmb in commit_active_weights(). If we saw the | |
968 | * updated hweight_gen, all the weight updates from | |
969 | * __propagate_active_weight() are visible too. | |
970 | * | |
971 | * We can race with weight updates during calculation and get it | |
972 | * wrong. However, hweight_gen would have changed and a future | |
973 | * reader will recalculate and we're guaranteed to discard the | |
974 | * wrong result soon. | |
975 | */ | |
976 | smp_rmb(); | |
977 | ||
978 | hwa = hwi = HWEIGHT_WHOLE; | |
979 | for (lvl = 0; lvl <= iocg->level - 1; lvl++) { | |
980 | struct ioc_gq *parent = iocg->ancestors[lvl]; | |
981 | struct ioc_gq *child = iocg->ancestors[lvl + 1]; | |
982 | u32 active_sum = READ_ONCE(parent->child_active_sum); | |
983 | u32 inuse_sum = READ_ONCE(parent->child_inuse_sum); | |
984 | u32 active = READ_ONCE(child->active); | |
985 | u32 inuse = READ_ONCE(child->inuse); | |
986 | ||
987 | /* we can race with deactivations and either may read as zero */ | |
988 | if (!active_sum || !inuse_sum) | |
989 | continue; | |
990 | ||
991 | active_sum = max(active, active_sum); | |
992 | hwa = hwa * active / active_sum; /* max 16bits * 10000 */ | |
993 | ||
994 | inuse_sum = max(inuse, inuse_sum); | |
995 | hwi = hwi * inuse / inuse_sum; /* max 16bits * 10000 */ | |
996 | } | |
997 | ||
998 | iocg->hweight_active = max_t(u32, hwa, 1); | |
999 | iocg->hweight_inuse = max_t(u32, hwi, 1); | |
1000 | iocg->hweight_gen = ioc_gen; | |
1001 | out: | |
1002 | if (hw_activep) | |
1003 | *hw_activep = iocg->hweight_active; | |
1004 | if (hw_inusep) | |
1005 | *hw_inusep = iocg->hweight_inuse; | |
1006 | } | |
1007 | ||
1008 | static void weight_updated(struct ioc_gq *iocg) | |
1009 | { | |
1010 | struct ioc *ioc = iocg->ioc; | |
1011 | struct blkcg_gq *blkg = iocg_to_blkg(iocg); | |
1012 | struct ioc_cgrp *iocc = blkcg_to_iocc(blkg->blkcg); | |
1013 | u32 weight; | |
1014 | ||
1015 | lockdep_assert_held(&ioc->lock); | |
1016 | ||
1017 | weight = iocg->cfg_weight ?: iocc->dfl_weight; | |
1018 | if (weight != iocg->weight && iocg->active) | |
1019 | propagate_active_weight(iocg, weight, | |
1020 | DIV64_U64_ROUND_UP(iocg->inuse * weight, iocg->weight)); | |
1021 | iocg->weight = weight; | |
1022 | } | |
1023 | ||
1024 | static bool iocg_activate(struct ioc_gq *iocg, struct ioc_now *now) | |
1025 | { | |
1026 | struct ioc *ioc = iocg->ioc; | |
1027 | u64 last_period, cur_period, max_period_delta; | |
1028 | u64 vtime, vmargin, vmin; | |
1029 | int i; | |
1030 | ||
1031 | /* | |
1032 | * If seem to be already active, just update the stamp to tell the | |
1033 | * timer that we're still active. We don't mind occassional races. | |
1034 | */ | |
1035 | if (!list_empty(&iocg->active_list)) { | |
1036 | ioc_now(ioc, now); | |
1037 | cur_period = atomic64_read(&ioc->cur_period); | |
1038 | if (atomic64_read(&iocg->active_period) != cur_period) | |
1039 | atomic64_set(&iocg->active_period, cur_period); | |
1040 | return true; | |
1041 | } | |
1042 | ||
1043 | /* racy check on internal node IOs, treat as root level IOs */ | |
1044 | if (iocg->child_active_sum) | |
1045 | return false; | |
1046 | ||
1047 | spin_lock_irq(&ioc->lock); | |
1048 | ||
1049 | ioc_now(ioc, now); | |
1050 | ||
1051 | /* update period */ | |
1052 | cur_period = atomic64_read(&ioc->cur_period); | |
1053 | last_period = atomic64_read(&iocg->active_period); | |
1054 | atomic64_set(&iocg->active_period, cur_period); | |
1055 | ||
1056 | /* already activated or breaking leaf-only constraint? */ | |
8b37bc27 JX |
1057 | if (!list_empty(&iocg->active_list)) |
1058 | goto succeed_unlock; | |
1059 | for (i = iocg->level - 1; i > 0; i--) | |
1060 | if (!list_empty(&iocg->ancestors[i]->active_list)) | |
7caa4715 | 1061 | goto fail_unlock; |
8b37bc27 | 1062 | |
7caa4715 TH |
1063 | if (iocg->child_active_sum) |
1064 | goto fail_unlock; | |
1065 | ||
1066 | /* | |
1067 | * vtime may wrap when vrate is raised substantially due to | |
1068 | * underestimated IO costs. Look at the period and ignore its | |
1069 | * vtime if the iocg has been idle for too long. Also, cap the | |
1070 | * budget it can start with to the margin. | |
1071 | */ | |
1072 | max_period_delta = DIV64_U64_ROUND_UP(VTIME_VALID_DUR, ioc->period_us); | |
1073 | vtime = atomic64_read(&iocg->vtime); | |
1074 | vmargin = ioc->margin_us * now->vrate; | |
1075 | vmin = now->vnow - vmargin; | |
1076 | ||
1077 | if (last_period + max_period_delta < cur_period || | |
1078 | time_before64(vtime, vmin)) { | |
1079 | atomic64_add(vmin - vtime, &iocg->vtime); | |
1080 | atomic64_add(vmin - vtime, &iocg->done_vtime); | |
1081 | vtime = vmin; | |
1082 | } | |
1083 | ||
1084 | /* | |
1085 | * Activate, propagate weight and start period timer if not | |
1086 | * running. Reset hweight_gen to avoid accidental match from | |
1087 | * wrapping. | |
1088 | */ | |
1089 | iocg->hweight_gen = atomic_read(&ioc->hweight_gen) - 1; | |
1090 | list_add(&iocg->active_list, &ioc->active_iocgs); | |
1091 | propagate_active_weight(iocg, iocg->weight, | |
1092 | iocg->last_inuse ?: iocg->weight); | |
1093 | ||
1094 | TRACE_IOCG_PATH(iocg_activate, iocg, now, | |
1095 | last_period, cur_period, vtime); | |
1096 | ||
1097 | iocg->last_vtime = vtime; | |
1098 | ||
1099 | if (ioc->running == IOC_IDLE) { | |
1100 | ioc->running = IOC_RUNNING; | |
1101 | ioc_start_period(ioc, now); | |
1102 | } | |
1103 | ||
8b37bc27 | 1104 | succeed_unlock: |
7caa4715 TH |
1105 | spin_unlock_irq(&ioc->lock); |
1106 | return true; | |
1107 | ||
1108 | fail_unlock: | |
1109 | spin_unlock_irq(&ioc->lock); | |
1110 | return false; | |
1111 | } | |
1112 | ||
1113 | static int iocg_wake_fn(struct wait_queue_entry *wq_entry, unsigned mode, | |
1114 | int flags, void *key) | |
1115 | { | |
1116 | struct iocg_wait *wait = container_of(wq_entry, struct iocg_wait, wait); | |
1117 | struct iocg_wake_ctx *ctx = (struct iocg_wake_ctx *)key; | |
1118 | u64 cost = abs_cost_to_cost(wait->abs_cost, ctx->hw_inuse); | |
1119 | ||
1120 | ctx->vbudget -= cost; | |
1121 | ||
1122 | if (ctx->vbudget < 0) | |
1123 | return -1; | |
1124 | ||
1125 | iocg_commit_bio(ctx->iocg, wait->bio, cost); | |
1126 | ||
1127 | /* | |
1128 | * autoremove_wake_function() removes the wait entry only when it | |
1129 | * actually changed the task state. We want the wait always | |
1130 | * removed. Remove explicitly and use default_wake_function(). | |
1131 | */ | |
1132 | list_del_init(&wq_entry->entry); | |
1133 | wait->committed = true; | |
1134 | ||
1135 | default_wake_function(wq_entry, mode, flags, key); | |
1136 | return 0; | |
1137 | } | |
1138 | ||
1139 | static void iocg_kick_waitq(struct ioc_gq *iocg, struct ioc_now *now) | |
1140 | { | |
1141 | struct ioc *ioc = iocg->ioc; | |
1142 | struct iocg_wake_ctx ctx = { .iocg = iocg }; | |
1143 | u64 margin_ns = (u64)(ioc->period_us * | |
1144 | WAITQ_TIMER_MARGIN_PCT / 100) * NSEC_PER_USEC; | |
0b80f986 | 1145 | u64 vdebt, vshortage, expires, oexpires; |
36a52481 TH |
1146 | s64 vbudget; |
1147 | u32 hw_inuse; | |
7caa4715 TH |
1148 | |
1149 | lockdep_assert_held(&iocg->waitq.lock); | |
1150 | ||
36a52481 TH |
1151 | current_hweight(iocg, NULL, &hw_inuse); |
1152 | vbudget = now->vnow - atomic64_read(&iocg->vtime); | |
1153 | ||
1154 | /* pay off debt */ | |
0b80f986 | 1155 | vdebt = abs_cost_to_cost(iocg->abs_vdebt, hw_inuse); |
36a52481 TH |
1156 | if (vdebt && vbudget > 0) { |
1157 | u64 delta = min_t(u64, vbudget, vdebt); | |
1158 | u64 abs_delta = min(cost_to_abs_cost(delta, hw_inuse), | |
0b80f986 | 1159 | iocg->abs_vdebt); |
36a52481 TH |
1160 | |
1161 | atomic64_add(delta, &iocg->vtime); | |
1162 | atomic64_add(delta, &iocg->done_vtime); | |
0b80f986 | 1163 | iocg->abs_vdebt -= abs_delta; |
36a52481 TH |
1164 | } |
1165 | ||
7caa4715 TH |
1166 | /* |
1167 | * Wake up the ones which are due and see how much vtime we'll need | |
1168 | * for the next one. | |
1169 | */ | |
36a52481 TH |
1170 | ctx.hw_inuse = hw_inuse; |
1171 | ctx.vbudget = vbudget - vdebt; | |
7caa4715 TH |
1172 | __wake_up_locked_key(&iocg->waitq, TASK_NORMAL, &ctx); |
1173 | if (!waitqueue_active(&iocg->waitq)) | |
1174 | return; | |
1175 | if (WARN_ON_ONCE(ctx.vbudget >= 0)) | |
1176 | return; | |
1177 | ||
1178 | /* determine next wakeup, add a quarter margin to guarantee chunking */ | |
1179 | vshortage = -ctx.vbudget; | |
1180 | expires = now->now_ns + | |
1181 | DIV64_U64_ROUND_UP(vshortage, now->vrate) * NSEC_PER_USEC; | |
1182 | expires += margin_ns / 4; | |
1183 | ||
1184 | /* if already active and close enough, don't bother */ | |
1185 | oexpires = ktime_to_ns(hrtimer_get_softexpires(&iocg->waitq_timer)); | |
1186 | if (hrtimer_is_queued(&iocg->waitq_timer) && | |
1187 | abs(oexpires - expires) <= margin_ns / 4) | |
1188 | return; | |
1189 | ||
1190 | hrtimer_start_range_ns(&iocg->waitq_timer, ns_to_ktime(expires), | |
1191 | margin_ns / 4, HRTIMER_MODE_ABS); | |
1192 | } | |
1193 | ||
1194 | static enum hrtimer_restart iocg_waitq_timer_fn(struct hrtimer *timer) | |
1195 | { | |
1196 | struct ioc_gq *iocg = container_of(timer, struct ioc_gq, waitq_timer); | |
1197 | struct ioc_now now; | |
1198 | unsigned long flags; | |
1199 | ||
1200 | ioc_now(iocg->ioc, &now); | |
1201 | ||
1202 | spin_lock_irqsave(&iocg->waitq.lock, flags); | |
1203 | iocg_kick_waitq(iocg, &now); | |
1204 | spin_unlock_irqrestore(&iocg->waitq.lock, flags); | |
1205 | ||
1206 | return HRTIMER_NORESTART; | |
1207 | } | |
1208 | ||
d7bd15a1 | 1209 | static bool iocg_kick_delay(struct ioc_gq *iocg, struct ioc_now *now, u64 cost) |
7caa4715 TH |
1210 | { |
1211 | struct ioc *ioc = iocg->ioc; | |
1212 | struct blkcg_gq *blkg = iocg_to_blkg(iocg); | |
1213 | u64 vtime = atomic64_read(&iocg->vtime); | |
1214 | u64 vmargin = ioc->margin_us * now->vrate; | |
1215 | u64 margin_ns = ioc->margin_us * NSEC_PER_USEC; | |
1216 | u64 expires, oexpires; | |
36a52481 TH |
1217 | u32 hw_inuse; |
1218 | ||
0b80f986 TH |
1219 | lockdep_assert_held(&iocg->waitq.lock); |
1220 | ||
36a52481 TH |
1221 | /* debt-adjust vtime */ |
1222 | current_hweight(iocg, NULL, &hw_inuse); | |
0b80f986 | 1223 | vtime += abs_cost_to_cost(iocg->abs_vdebt, hw_inuse); |
7caa4715 | 1224 | |
0b80f986 TH |
1225 | /* |
1226 | * Clear or maintain depending on the overage. Non-zero vdebt is what | |
1227 | * guarantees that @iocg is online and future iocg_kick_delay() will | |
1228 | * clear use_delay. Don't leave it on when there's no vdebt. | |
1229 | */ | |
1230 | if (!iocg->abs_vdebt || time_before_eq64(vtime, now->vnow)) { | |
7caa4715 | 1231 | blkcg_clear_delay(blkg); |
d7bd15a1 | 1232 | return false; |
7caa4715 TH |
1233 | } |
1234 | if (!atomic_read(&blkg->use_delay) && | |
1235 | time_before_eq64(vtime, now->vnow + vmargin)) | |
d7bd15a1 | 1236 | return false; |
7caa4715 TH |
1237 | |
1238 | /* use delay */ | |
1239 | if (cost) { | |
1240 | u64 cost_ns = DIV64_U64_ROUND_UP(cost * NSEC_PER_USEC, | |
1241 | now->vrate); | |
1242 | blkcg_add_delay(blkg, now->now_ns, cost_ns); | |
1243 | } | |
1244 | blkcg_use_delay(blkg); | |
1245 | ||
1246 | expires = now->now_ns + DIV64_U64_ROUND_UP(vtime - now->vnow, | |
1247 | now->vrate) * NSEC_PER_USEC; | |
1248 | ||
1249 | /* if already active and close enough, don't bother */ | |
1250 | oexpires = ktime_to_ns(hrtimer_get_softexpires(&iocg->delay_timer)); | |
1251 | if (hrtimer_is_queued(&iocg->delay_timer) && | |
1252 | abs(oexpires - expires) <= margin_ns / 4) | |
d7bd15a1 | 1253 | return true; |
7caa4715 TH |
1254 | |
1255 | hrtimer_start_range_ns(&iocg->delay_timer, ns_to_ktime(expires), | |
1256 | margin_ns / 4, HRTIMER_MODE_ABS); | |
d7bd15a1 | 1257 | return true; |
7caa4715 TH |
1258 | } |
1259 | ||
1260 | static enum hrtimer_restart iocg_delay_timer_fn(struct hrtimer *timer) | |
1261 | { | |
1262 | struct ioc_gq *iocg = container_of(timer, struct ioc_gq, delay_timer); | |
1263 | struct ioc_now now; | |
0b80f986 | 1264 | unsigned long flags; |
7caa4715 | 1265 | |
0b80f986 | 1266 | spin_lock_irqsave(&iocg->waitq.lock, flags); |
7caa4715 TH |
1267 | ioc_now(iocg->ioc, &now); |
1268 | iocg_kick_delay(iocg, &now, 0); | |
0b80f986 | 1269 | spin_unlock_irqrestore(&iocg->waitq.lock, flags); |
7caa4715 TH |
1270 | |
1271 | return HRTIMER_NORESTART; | |
1272 | } | |
1273 | ||
1274 | static void ioc_lat_stat(struct ioc *ioc, u32 *missed_ppm_ar, u32 *rq_wait_pct_p) | |
1275 | { | |
1276 | u32 nr_met[2] = { }; | |
1277 | u32 nr_missed[2] = { }; | |
1278 | u64 rq_wait_ns = 0; | |
1279 | int cpu, rw; | |
1280 | ||
1281 | for_each_online_cpu(cpu) { | |
1282 | struct ioc_pcpu_stat *stat = per_cpu_ptr(ioc->pcpu_stat, cpu); | |
1283 | u64 this_rq_wait_ns; | |
1284 | ||
1285 | for (rw = READ; rw <= WRITE; rw++) { | |
1286 | u32 this_met = READ_ONCE(stat->missed[rw].nr_met); | |
1287 | u32 this_missed = READ_ONCE(stat->missed[rw].nr_missed); | |
1288 | ||
1289 | nr_met[rw] += this_met - stat->missed[rw].last_met; | |
1290 | nr_missed[rw] += this_missed - stat->missed[rw].last_missed; | |
1291 | stat->missed[rw].last_met = this_met; | |
1292 | stat->missed[rw].last_missed = this_missed; | |
1293 | } | |
1294 | ||
1295 | this_rq_wait_ns = READ_ONCE(stat->rq_wait_ns); | |
1296 | rq_wait_ns += this_rq_wait_ns - stat->last_rq_wait_ns; | |
1297 | stat->last_rq_wait_ns = this_rq_wait_ns; | |
1298 | } | |
1299 | ||
1300 | for (rw = READ; rw <= WRITE; rw++) { | |
1301 | if (nr_met[rw] + nr_missed[rw]) | |
1302 | missed_ppm_ar[rw] = | |
1303 | DIV64_U64_ROUND_UP((u64)nr_missed[rw] * MILLION, | |
1304 | nr_met[rw] + nr_missed[rw]); | |
1305 | else | |
1306 | missed_ppm_ar[rw] = 0; | |
1307 | } | |
1308 | ||
1309 | *rq_wait_pct_p = div64_u64(rq_wait_ns * 100, | |
1310 | ioc->period_us * NSEC_PER_USEC); | |
1311 | } | |
1312 | ||
1313 | /* was iocg idle this period? */ | |
1314 | static bool iocg_is_idle(struct ioc_gq *iocg) | |
1315 | { | |
1316 | struct ioc *ioc = iocg->ioc; | |
1317 | ||
1318 | /* did something get issued this period? */ | |
1319 | if (atomic64_read(&iocg->active_period) == | |
1320 | atomic64_read(&ioc->cur_period)) | |
1321 | return false; | |
1322 | ||
1323 | /* is something in flight? */ | |
dcd6589b | 1324 | if (atomic64_read(&iocg->done_vtime) != atomic64_read(&iocg->vtime)) |
7caa4715 TH |
1325 | return false; |
1326 | ||
1327 | return true; | |
1328 | } | |
1329 | ||
1330 | /* returns usage with margin added if surplus is large enough */ | |
1331 | static u32 surplus_adjusted_hweight_inuse(u32 usage, u32 hw_inuse) | |
1332 | { | |
1333 | /* add margin */ | |
1334 | usage = DIV_ROUND_UP(usage * SURPLUS_SCALE_PCT, 100); | |
1335 | usage += SURPLUS_SCALE_ABS; | |
1336 | ||
1337 | /* don't bother if the surplus is too small */ | |
1338 | if (usage + SURPLUS_MIN_ADJ_DELTA > hw_inuse) | |
1339 | return 0; | |
1340 | ||
1341 | return usage; | |
1342 | } | |
1343 | ||
1344 | static void ioc_timer_fn(struct timer_list *timer) | |
1345 | { | |
1346 | struct ioc *ioc = container_of(timer, struct ioc, timer); | |
1347 | struct ioc_gq *iocg, *tiocg; | |
1348 | struct ioc_now now; | |
1349 | int nr_surpluses = 0, nr_shortages = 0, nr_lagging = 0; | |
1350 | u32 ppm_rthr = MILLION - ioc->params.qos[QOS_RPPM]; | |
1351 | u32 ppm_wthr = MILLION - ioc->params.qos[QOS_WPPM]; | |
1352 | u32 missed_ppm[2], rq_wait_pct; | |
1353 | u64 period_vtime; | |
25d41e4a | 1354 | int prev_busy_level, i; |
7caa4715 TH |
1355 | |
1356 | /* how were the latencies during the period? */ | |
1357 | ioc_lat_stat(ioc, missed_ppm, &rq_wait_pct); | |
1358 | ||
1359 | /* take care of active iocgs */ | |
1360 | spin_lock_irq(&ioc->lock); | |
1361 | ||
1362 | ioc_now(ioc, &now); | |
1363 | ||
1364 | period_vtime = now.vnow - ioc->period_at_vtime; | |
1365 | if (WARN_ON_ONCE(!period_vtime)) { | |
1366 | spin_unlock_irq(&ioc->lock); | |
1367 | return; | |
1368 | } | |
1369 | ||
1370 | /* | |
1371 | * Waiters determine the sleep durations based on the vrate they | |
1372 | * saw at the time of sleep. If vrate has increased, some waiters | |
1373 | * could be sleeping for too long. Wake up tardy waiters which | |
1374 | * should have woken up in the last period and expire idle iocgs. | |
1375 | */ | |
1376 | list_for_each_entry_safe(iocg, tiocg, &ioc->active_iocgs, active_list) { | |
0b80f986 TH |
1377 | if (!waitqueue_active(&iocg->waitq) && iocg->abs_vdebt && |
1378 | !iocg_is_idle(iocg)) | |
7caa4715 TH |
1379 | continue; |
1380 | ||
1381 | spin_lock(&iocg->waitq.lock); | |
1382 | ||
0b80f986 | 1383 | if (waitqueue_active(&iocg->waitq) || iocg->abs_vdebt) { |
7caa4715 TH |
1384 | /* might be oversleeping vtime / hweight changes, kick */ |
1385 | iocg_kick_waitq(iocg, &now); | |
1386 | iocg_kick_delay(iocg, &now, 0); | |
1387 | } else if (iocg_is_idle(iocg)) { | |
1388 | /* no waiter and idle, deactivate */ | |
1389 | iocg->last_inuse = iocg->inuse; | |
1390 | __propagate_active_weight(iocg, 0, 0); | |
1391 | list_del_init(&iocg->active_list); | |
1392 | } | |
1393 | ||
1394 | spin_unlock(&iocg->waitq.lock); | |
1395 | } | |
1396 | commit_active_weights(ioc); | |
1397 | ||
1398 | /* calc usages and see whether some weights need to be moved around */ | |
1399 | list_for_each_entry(iocg, &ioc->active_iocgs, active_list) { | |
1400 | u64 vdone, vtime, vusage, vmargin, vmin; | |
1401 | u32 hw_active, hw_inuse, usage; | |
1402 | ||
1403 | /* | |
1404 | * Collect unused and wind vtime closer to vnow to prevent | |
1405 | * iocgs from accumulating a large amount of budget. | |
1406 | */ | |
1407 | vdone = atomic64_read(&iocg->done_vtime); | |
1408 | vtime = atomic64_read(&iocg->vtime); | |
1409 | current_hweight(iocg, &hw_active, &hw_inuse); | |
1410 | ||
1411 | /* | |
1412 | * Latency QoS detection doesn't account for IOs which are | |
1413 | * in-flight for longer than a period. Detect them by | |
1414 | * comparing vdone against period start. If lagging behind | |
1415 | * IOs from past periods, don't increase vrate. | |
1416 | */ | |
7cd806a9 TH |
1417 | if ((ppm_rthr != MILLION || ppm_wthr != MILLION) && |
1418 | !atomic_read(&iocg_to_blkg(iocg)->use_delay) && | |
7caa4715 TH |
1419 | time_after64(vtime, vdone) && |
1420 | time_after64(vtime, now.vnow - | |
1421 | MAX_LAGGING_PERIODS * period_vtime) && | |
1422 | time_before64(vdone, now.vnow - period_vtime)) | |
1423 | nr_lagging++; | |
1424 | ||
1425 | if (waitqueue_active(&iocg->waitq)) | |
1426 | vusage = now.vnow - iocg->last_vtime; | |
1427 | else if (time_before64(iocg->last_vtime, vtime)) | |
1428 | vusage = vtime - iocg->last_vtime; | |
1429 | else | |
1430 | vusage = 0; | |
1431 | ||
1432 | iocg->last_vtime += vusage; | |
1433 | /* | |
1434 | * Factor in in-flight vtime into vusage to avoid | |
1435 | * high-latency completions appearing as idle. This should | |
1436 | * be done after the above ->last_time adjustment. | |
1437 | */ | |
1438 | vusage = max(vusage, vtime - vdone); | |
1439 | ||
1440 | /* calculate hweight based usage ratio and record */ | |
1441 | if (vusage) { | |
1442 | usage = DIV64_U64_ROUND_UP(vusage * hw_inuse, | |
1443 | period_vtime); | |
1444 | iocg->usage_idx = (iocg->usage_idx + 1) % NR_USAGE_SLOTS; | |
1445 | iocg->usages[iocg->usage_idx] = usage; | |
1446 | } else { | |
1447 | usage = 0; | |
1448 | } | |
1449 | ||
1450 | /* see whether there's surplus vtime */ | |
1451 | vmargin = ioc->margin_us * now.vrate; | |
1452 | vmin = now.vnow - vmargin; | |
1453 | ||
1454 | iocg->has_surplus = false; | |
1455 | ||
1456 | if (!waitqueue_active(&iocg->waitq) && | |
1457 | time_before64(vtime, vmin)) { | |
1458 | u64 delta = vmin - vtime; | |
1459 | ||
1460 | /* throw away surplus vtime */ | |
1461 | atomic64_add(delta, &iocg->vtime); | |
1462 | atomic64_add(delta, &iocg->done_vtime); | |
1463 | iocg->last_vtime += delta; | |
1464 | /* if usage is sufficiently low, maybe it can donate */ | |
1465 | if (surplus_adjusted_hweight_inuse(usage, hw_inuse)) { | |
1466 | iocg->has_surplus = true; | |
1467 | nr_surpluses++; | |
1468 | } | |
1469 | } else if (hw_inuse < hw_active) { | |
1470 | u32 new_hwi, new_inuse; | |
1471 | ||
1472 | /* was donating but might need to take back some */ | |
1473 | if (waitqueue_active(&iocg->waitq)) { | |
1474 | new_hwi = hw_active; | |
1475 | } else { | |
1476 | new_hwi = max(hw_inuse, | |
1477 | usage * SURPLUS_SCALE_PCT / 100 + | |
1478 | SURPLUS_SCALE_ABS); | |
1479 | } | |
1480 | ||
1481 | new_inuse = div64_u64((u64)iocg->inuse * new_hwi, | |
1482 | hw_inuse); | |
1483 | new_inuse = clamp_t(u32, new_inuse, 1, iocg->active); | |
1484 | ||
1485 | if (new_inuse > iocg->inuse) { | |
1486 | TRACE_IOCG_PATH(inuse_takeback, iocg, &now, | |
1487 | iocg->inuse, new_inuse, | |
1488 | hw_inuse, new_hwi); | |
1489 | __propagate_active_weight(iocg, iocg->weight, | |
1490 | new_inuse); | |
1491 | } | |
1492 | } else { | |
1493 | /* genuninely out of vtime */ | |
1494 | nr_shortages++; | |
1495 | } | |
1496 | } | |
1497 | ||
1498 | if (!nr_shortages || !nr_surpluses) | |
1499 | goto skip_surplus_transfers; | |
1500 | ||
1501 | /* there are both shortages and surpluses, transfer surpluses */ | |
1502 | list_for_each_entry(iocg, &ioc->active_iocgs, active_list) { | |
1503 | u32 usage, hw_active, hw_inuse, new_hwi, new_inuse; | |
1504 | int nr_valid = 0; | |
1505 | ||
1506 | if (!iocg->has_surplus) | |
1507 | continue; | |
1508 | ||
1509 | /* base the decision on max historical usage */ | |
1510 | for (i = 0, usage = 0; i < NR_USAGE_SLOTS; i++) { | |
1511 | if (iocg->usages[i]) { | |
1512 | usage = max(usage, iocg->usages[i]); | |
1513 | nr_valid++; | |
1514 | } | |
1515 | } | |
1516 | if (nr_valid < MIN_VALID_USAGES) | |
1517 | continue; | |
1518 | ||
1519 | current_hweight(iocg, &hw_active, &hw_inuse); | |
1520 | new_hwi = surplus_adjusted_hweight_inuse(usage, hw_inuse); | |
1521 | if (!new_hwi) | |
1522 | continue; | |
1523 | ||
1524 | new_inuse = DIV64_U64_ROUND_UP((u64)iocg->inuse * new_hwi, | |
1525 | hw_inuse); | |
1526 | if (new_inuse < iocg->inuse) { | |
1527 | TRACE_IOCG_PATH(inuse_giveaway, iocg, &now, | |
1528 | iocg->inuse, new_inuse, | |
1529 | hw_inuse, new_hwi); | |
1530 | __propagate_active_weight(iocg, iocg->weight, new_inuse); | |
1531 | } | |
1532 | } | |
1533 | skip_surplus_transfers: | |
1534 | commit_active_weights(ioc); | |
1535 | ||
1536 | /* | |
1537 | * If q is getting clogged or we're missing too much, we're issuing | |
1538 | * too much IO and should lower vtime rate. If we're not missing | |
1539 | * and experiencing shortages but not surpluses, we're too stingy | |
1540 | * and should increase vtime rate. | |
1541 | */ | |
25d41e4a | 1542 | prev_busy_level = ioc->busy_level; |
7caa4715 TH |
1543 | if (rq_wait_pct > RQ_WAIT_BUSY_PCT || |
1544 | missed_ppm[READ] > ppm_rthr || | |
1545 | missed_ppm[WRITE] > ppm_wthr) { | |
1546 | ioc->busy_level = max(ioc->busy_level, 0); | |
1547 | ioc->busy_level++; | |
7cd806a9 | 1548 | } else if (rq_wait_pct <= RQ_WAIT_BUSY_PCT * UNBUSY_THR_PCT / 100 && |
7caa4715 TH |
1549 | missed_ppm[READ] <= ppm_rthr * UNBUSY_THR_PCT / 100 && |
1550 | missed_ppm[WRITE] <= ppm_wthr * UNBUSY_THR_PCT / 100) { | |
7cd806a9 TH |
1551 | /* take action iff there is contention */ |
1552 | if (nr_shortages && !nr_lagging) { | |
1553 | ioc->busy_level = min(ioc->busy_level, 0); | |
1554 | /* redistribute surpluses first */ | |
1555 | if (!nr_surpluses) | |
1556 | ioc->busy_level--; | |
1557 | } | |
7caa4715 TH |
1558 | } else { |
1559 | ioc->busy_level = 0; | |
1560 | } | |
1561 | ||
1562 | ioc->busy_level = clamp(ioc->busy_level, -1000, 1000); | |
1563 | ||
7cd806a9 | 1564 | if (ioc->busy_level > 0 || (ioc->busy_level < 0 && !nr_lagging)) { |
7caa4715 TH |
1565 | u64 vrate = atomic64_read(&ioc->vtime_rate); |
1566 | u64 vrate_min = ioc->vrate_min, vrate_max = ioc->vrate_max; | |
1567 | ||
1568 | /* rq_wait signal is always reliable, ignore user vrate_min */ | |
1569 | if (rq_wait_pct > RQ_WAIT_BUSY_PCT) | |
1570 | vrate_min = VRATE_MIN; | |
1571 | ||
1572 | /* | |
1573 | * If vrate is out of bounds, apply clamp gradually as the | |
1574 | * bounds can change abruptly. Otherwise, apply busy_level | |
1575 | * based adjustment. | |
1576 | */ | |
1577 | if (vrate < vrate_min) { | |
1578 | vrate = div64_u64(vrate * (100 + VRATE_CLAMP_ADJ_PCT), | |
1579 | 100); | |
1580 | vrate = min(vrate, vrate_min); | |
1581 | } else if (vrate > vrate_max) { | |
1582 | vrate = div64_u64(vrate * (100 - VRATE_CLAMP_ADJ_PCT), | |
1583 | 100); | |
1584 | vrate = max(vrate, vrate_max); | |
1585 | } else { | |
1586 | int idx = min_t(int, abs(ioc->busy_level), | |
1587 | ARRAY_SIZE(vrate_adj_pct) - 1); | |
1588 | u32 adj_pct = vrate_adj_pct[idx]; | |
1589 | ||
1590 | if (ioc->busy_level > 0) | |
1591 | adj_pct = 100 - adj_pct; | |
1592 | else | |
1593 | adj_pct = 100 + adj_pct; | |
1594 | ||
1595 | vrate = clamp(DIV64_U64_ROUND_UP(vrate * adj_pct, 100), | |
1596 | vrate_min, vrate_max); | |
1597 | } | |
1598 | ||
d6c8e949 | 1599 | trace_iocost_ioc_vrate_adj(ioc, vrate, missed_ppm, rq_wait_pct, |
7caa4715 TH |
1600 | nr_lagging, nr_shortages, |
1601 | nr_surpluses); | |
1602 | ||
1603 | atomic64_set(&ioc->vtime_rate, vrate); | |
1604 | ioc->inuse_margin_vtime = DIV64_U64_ROUND_UP( | |
1605 | ioc->period_us * vrate * INUSE_MARGIN_PCT, 100); | |
25d41e4a TH |
1606 | } else if (ioc->busy_level != prev_busy_level || nr_lagging) { |
1607 | trace_iocost_ioc_vrate_adj(ioc, atomic64_read(&ioc->vtime_rate), | |
d6c8e949 | 1608 | missed_ppm, rq_wait_pct, nr_lagging, |
25d41e4a | 1609 | nr_shortages, nr_surpluses); |
7caa4715 TH |
1610 | } |
1611 | ||
1612 | ioc_refresh_params(ioc, false); | |
1613 | ||
1614 | /* | |
1615 | * This period is done. Move onto the next one. If nothing's | |
1616 | * going on with the device, stop the timer. | |
1617 | */ | |
1618 | atomic64_inc(&ioc->cur_period); | |
1619 | ||
1620 | if (ioc->running != IOC_STOP) { | |
1621 | if (!list_empty(&ioc->active_iocgs)) { | |
1622 | ioc_start_period(ioc, &now); | |
1623 | } else { | |
1624 | ioc->busy_level = 0; | |
1625 | ioc->running = IOC_IDLE; | |
1626 | } | |
1627 | } | |
1628 | ||
1629 | spin_unlock_irq(&ioc->lock); | |
1630 | } | |
1631 | ||
1632 | static void calc_vtime_cost_builtin(struct bio *bio, struct ioc_gq *iocg, | |
1633 | bool is_merge, u64 *costp) | |
1634 | { | |
1635 | struct ioc *ioc = iocg->ioc; | |
1636 | u64 coef_seqio, coef_randio, coef_page; | |
1637 | u64 pages = max_t(u64, bio_sectors(bio) >> IOC_SECT_TO_PAGE_SHIFT, 1); | |
1638 | u64 seek_pages = 0; | |
1639 | u64 cost = 0; | |
1640 | ||
1641 | switch (bio_op(bio)) { | |
1642 | case REQ_OP_READ: | |
1643 | coef_seqio = ioc->params.lcoefs[LCOEF_RSEQIO]; | |
1644 | coef_randio = ioc->params.lcoefs[LCOEF_RRANDIO]; | |
1645 | coef_page = ioc->params.lcoefs[LCOEF_RPAGE]; | |
1646 | break; | |
1647 | case REQ_OP_WRITE: | |
1648 | coef_seqio = ioc->params.lcoefs[LCOEF_WSEQIO]; | |
1649 | coef_randio = ioc->params.lcoefs[LCOEF_WRANDIO]; | |
1650 | coef_page = ioc->params.lcoefs[LCOEF_WPAGE]; | |
1651 | break; | |
1652 | default: | |
1653 | goto out; | |
1654 | } | |
1655 | ||
1656 | if (iocg->cursor) { | |
1657 | seek_pages = abs(bio->bi_iter.bi_sector - iocg->cursor); | |
1658 | seek_pages >>= IOC_SECT_TO_PAGE_SHIFT; | |
1659 | } | |
1660 | ||
1661 | if (!is_merge) { | |
1662 | if (seek_pages > LCOEF_RANDIO_PAGES) { | |
1663 | cost += coef_randio; | |
1664 | } else { | |
1665 | cost += coef_seqio; | |
1666 | } | |
1667 | } | |
1668 | cost += pages * coef_page; | |
1669 | out: | |
1670 | *costp = cost; | |
1671 | } | |
1672 | ||
1673 | static u64 calc_vtime_cost(struct bio *bio, struct ioc_gq *iocg, bool is_merge) | |
1674 | { | |
1675 | u64 cost; | |
1676 | ||
1677 | calc_vtime_cost_builtin(bio, iocg, is_merge, &cost); | |
1678 | return cost; | |
1679 | } | |
1680 | ||
1681 | static void ioc_rqos_throttle(struct rq_qos *rqos, struct bio *bio) | |
1682 | { | |
1683 | struct blkcg_gq *blkg = bio->bi_blkg; | |
1684 | struct ioc *ioc = rqos_to_ioc(rqos); | |
1685 | struct ioc_gq *iocg = blkg_to_iocg(blkg); | |
1686 | struct ioc_now now; | |
1687 | struct iocg_wait wait; | |
1688 | u32 hw_active, hw_inuse; | |
1689 | u64 abs_cost, cost, vtime; | |
1690 | ||
1691 | /* bypass IOs if disabled or for root cgroup */ | |
1692 | if (!ioc->enabled || !iocg->level) | |
1693 | return; | |
1694 | ||
1695 | /* always activate so that even 0 cost IOs get protected to some level */ | |
1696 | if (!iocg_activate(iocg, &now)) | |
1697 | return; | |
1698 | ||
1699 | /* calculate the absolute vtime cost */ | |
1700 | abs_cost = calc_vtime_cost(bio, iocg, false); | |
1701 | if (!abs_cost) | |
1702 | return; | |
1703 | ||
1704 | iocg->cursor = bio_end_sector(bio); | |
1705 | ||
1706 | vtime = atomic64_read(&iocg->vtime); | |
1707 | current_hweight(iocg, &hw_active, &hw_inuse); | |
1708 | ||
1709 | if (hw_inuse < hw_active && | |
1710 | time_after_eq64(vtime + ioc->inuse_margin_vtime, now.vnow)) { | |
1711 | TRACE_IOCG_PATH(inuse_reset, iocg, &now, | |
1712 | iocg->inuse, iocg->weight, hw_inuse, hw_active); | |
1713 | spin_lock_irq(&ioc->lock); | |
1714 | propagate_active_weight(iocg, iocg->weight, iocg->weight); | |
1715 | spin_unlock_irq(&ioc->lock); | |
1716 | current_hweight(iocg, &hw_active, &hw_inuse); | |
1717 | } | |
1718 | ||
1719 | cost = abs_cost_to_cost(abs_cost, hw_inuse); | |
1720 | ||
1721 | /* | |
1722 | * If no one's waiting and within budget, issue right away. The | |
1723 | * tests are racy but the races aren't systemic - we only miss once | |
1724 | * in a while which is fine. | |
1725 | */ | |
0b80f986 | 1726 | if (!waitqueue_active(&iocg->waitq) && !iocg->abs_vdebt && |
7caa4715 TH |
1727 | time_before_eq64(vtime + cost, now.vnow)) { |
1728 | iocg_commit_bio(iocg, bio, cost); | |
1729 | return; | |
1730 | } | |
1731 | ||
36a52481 | 1732 | /* |
0b80f986 TH |
1733 | * We activated above but w/o any synchronization. Deactivation is |
1734 | * synchronized with waitq.lock and we won't get deactivated as long | |
1735 | * as we're waiting or has debt, so we're good if we're activated | |
1736 | * here. In the unlikely case that we aren't, just issue the IO. | |
1737 | */ | |
1738 | spin_lock_irq(&iocg->waitq.lock); | |
1739 | ||
1740 | if (unlikely(list_empty(&iocg->active_list))) { | |
1741 | spin_unlock_irq(&iocg->waitq.lock); | |
1742 | iocg_commit_bio(iocg, bio, cost); | |
1743 | return; | |
1744 | } | |
1745 | ||
1746 | /* | |
1747 | * We're over budget. If @bio has to be issued regardless, remember | |
1748 | * the abs_cost instead of advancing vtime. iocg_kick_waitq() will pay | |
1749 | * off the debt before waking more IOs. | |
1750 | * | |
36a52481 | 1751 | * This way, the debt is continuously paid off each period with the |
0b80f986 TH |
1752 | * actual budget available to the cgroup. If we just wound vtime, we |
1753 | * would incorrectly use the current hw_inuse for the entire amount | |
1754 | * which, for example, can lead to the cgroup staying blocked for a | |
1755 | * long time even with substantially raised hw_inuse. | |
1756 | * | |
1757 | * An iocg with vdebt should stay online so that the timer can keep | |
1758 | * deducting its vdebt and [de]activate use_delay mechanism | |
1759 | * accordingly. We don't want to race against the timer trying to | |
1760 | * clear them and leave @iocg inactive w/ dangling use_delay heavily | |
1761 | * penalizing the cgroup and its descendants. | |
36a52481 | 1762 | */ |
7caa4715 | 1763 | if (bio_issue_as_root_blkg(bio) || fatal_signal_pending(current)) { |
0b80f986 | 1764 | iocg->abs_vdebt += abs_cost; |
d7bd15a1 TH |
1765 | if (iocg_kick_delay(iocg, &now, cost)) |
1766 | blkcg_schedule_throttle(rqos->q, | |
1767 | (bio->bi_opf & REQ_SWAP) == REQ_SWAP); | |
0b80f986 | 1768 | spin_unlock_irq(&iocg->waitq.lock); |
7caa4715 TH |
1769 | return; |
1770 | } | |
1771 | ||
1772 | /* | |
1773 | * Append self to the waitq and schedule the wakeup timer if we're | |
1774 | * the first waiter. The timer duration is calculated based on the | |
1775 | * current vrate. vtime and hweight changes can make it too short | |
1776 | * or too long. Each wait entry records the absolute cost it's | |
1777 | * waiting for to allow re-evaluation using a custom wait entry. | |
1778 | * | |
1779 | * If too short, the timer simply reschedules itself. If too long, | |
1780 | * the period timer will notice and trigger wakeups. | |
1781 | * | |
1782 | * All waiters are on iocg->waitq and the wait states are | |
1783 | * synchronized using waitq.lock. | |
1784 | */ | |
7caa4715 TH |
1785 | init_waitqueue_func_entry(&wait.wait, iocg_wake_fn); |
1786 | wait.wait.private = current; | |
1787 | wait.bio = bio; | |
1788 | wait.abs_cost = abs_cost; | |
1789 | wait.committed = false; /* will be set true by waker */ | |
1790 | ||
1791 | __add_wait_queue_entry_tail(&iocg->waitq, &wait.wait); | |
1792 | iocg_kick_waitq(iocg, &now); | |
1793 | ||
1794 | spin_unlock_irq(&iocg->waitq.lock); | |
1795 | ||
1796 | while (true) { | |
1797 | set_current_state(TASK_UNINTERRUPTIBLE); | |
1798 | if (wait.committed) | |
1799 | break; | |
1800 | io_schedule(); | |
1801 | } | |
1802 | ||
1803 | /* waker already committed us, proceed */ | |
1804 | finish_wait(&iocg->waitq, &wait.wait); | |
1805 | } | |
1806 | ||
1807 | static void ioc_rqos_merge(struct rq_qos *rqos, struct request *rq, | |
1808 | struct bio *bio) | |
1809 | { | |
1810 | struct ioc_gq *iocg = blkg_to_iocg(bio->bi_blkg); | |
e1518f63 | 1811 | struct ioc *ioc = iocg->ioc; |
7caa4715 | 1812 | sector_t bio_end = bio_end_sector(bio); |
e1518f63 | 1813 | struct ioc_now now; |
7caa4715 TH |
1814 | u32 hw_inuse; |
1815 | u64 abs_cost, cost; | |
0b80f986 | 1816 | unsigned long flags; |
7caa4715 | 1817 | |
e1518f63 TH |
1818 | /* bypass if disabled or for root cgroup */ |
1819 | if (!ioc->enabled || !iocg->level) | |
7caa4715 TH |
1820 | return; |
1821 | ||
1822 | abs_cost = calc_vtime_cost(bio, iocg, true); | |
1823 | if (!abs_cost) | |
1824 | return; | |
1825 | ||
e1518f63 TH |
1826 | ioc_now(ioc, &now); |
1827 | current_hweight(iocg, NULL, &hw_inuse); | |
1828 | cost = abs_cost_to_cost(abs_cost, hw_inuse); | |
1829 | ||
7caa4715 TH |
1830 | /* update cursor if backmerging into the request at the cursor */ |
1831 | if (blk_rq_pos(rq) < bio_end && | |
1832 | blk_rq_pos(rq) + blk_rq_sectors(rq) == iocg->cursor) | |
1833 | iocg->cursor = bio_end; | |
1834 | ||
e1518f63 | 1835 | /* |
0b80f986 TH |
1836 | * Charge if there's enough vtime budget and the existing request has |
1837 | * cost assigned. | |
e1518f63 TH |
1838 | */ |
1839 | if (rq->bio && rq->bio->bi_iocost_cost && | |
0b80f986 | 1840 | time_before_eq64(atomic64_read(&iocg->vtime) + cost, now.vnow)) { |
e1518f63 | 1841 | iocg_commit_bio(iocg, bio, cost); |
0b80f986 TH |
1842 | return; |
1843 | } | |
1844 | ||
1845 | /* | |
1846 | * Otherwise, account it as debt if @iocg is online, which it should | |
1847 | * be for the vast majority of cases. See debt handling in | |
1848 | * ioc_rqos_throttle() for details. | |
1849 | */ | |
1850 | spin_lock_irqsave(&iocg->waitq.lock, flags); | |
1851 | if (likely(!list_empty(&iocg->active_list))) { | |
1852 | iocg->abs_vdebt += abs_cost; | |
1853 | iocg_kick_delay(iocg, &now, cost); | |
1854 | } else { | |
1855 | iocg_commit_bio(iocg, bio, cost); | |
1856 | } | |
1857 | spin_unlock_irqrestore(&iocg->waitq.lock, flags); | |
7caa4715 TH |
1858 | } |
1859 | ||
1860 | static void ioc_rqos_done_bio(struct rq_qos *rqos, struct bio *bio) | |
1861 | { | |
1862 | struct ioc_gq *iocg = blkg_to_iocg(bio->bi_blkg); | |
1863 | ||
1864 | if (iocg && bio->bi_iocost_cost) | |
1865 | atomic64_add(bio->bi_iocost_cost, &iocg->done_vtime); | |
1866 | } | |
1867 | ||
1868 | static void ioc_rqos_done(struct rq_qos *rqos, struct request *rq) | |
1869 | { | |
1870 | struct ioc *ioc = rqos_to_ioc(rqos); | |
1871 | u64 on_q_ns, rq_wait_ns; | |
1872 | int pidx, rw; | |
1873 | ||
1874 | if (!ioc->enabled || !rq->alloc_time_ns || !rq->start_time_ns) | |
1875 | return; | |
1876 | ||
1877 | switch (req_op(rq) & REQ_OP_MASK) { | |
1878 | case REQ_OP_READ: | |
1879 | pidx = QOS_RLAT; | |
1880 | rw = READ; | |
1881 | break; | |
1882 | case REQ_OP_WRITE: | |
1883 | pidx = QOS_WLAT; | |
1884 | rw = WRITE; | |
1885 | break; | |
1886 | default: | |
1887 | return; | |
1888 | } | |
1889 | ||
1890 | on_q_ns = ktime_get_ns() - rq->alloc_time_ns; | |
1891 | rq_wait_ns = rq->start_time_ns - rq->alloc_time_ns; | |
1892 | ||
1893 | if (on_q_ns <= ioc->params.qos[pidx] * NSEC_PER_USEC) | |
1894 | this_cpu_inc(ioc->pcpu_stat->missed[rw].nr_met); | |
1895 | else | |
1896 | this_cpu_inc(ioc->pcpu_stat->missed[rw].nr_missed); | |
1897 | ||
1898 | this_cpu_add(ioc->pcpu_stat->rq_wait_ns, rq_wait_ns); | |
1899 | } | |
1900 | ||
1901 | static void ioc_rqos_queue_depth_changed(struct rq_qos *rqos) | |
1902 | { | |
1903 | struct ioc *ioc = rqos_to_ioc(rqos); | |
1904 | ||
1905 | spin_lock_irq(&ioc->lock); | |
1906 | ioc_refresh_params(ioc, false); | |
1907 | spin_unlock_irq(&ioc->lock); | |
1908 | } | |
1909 | ||
1910 | static void ioc_rqos_exit(struct rq_qos *rqos) | |
1911 | { | |
1912 | struct ioc *ioc = rqos_to_ioc(rqos); | |
1913 | ||
1914 | blkcg_deactivate_policy(rqos->q, &blkcg_policy_iocost); | |
1915 | ||
1916 | spin_lock_irq(&ioc->lock); | |
1917 | ioc->running = IOC_STOP; | |
1918 | spin_unlock_irq(&ioc->lock); | |
1919 | ||
1920 | del_timer_sync(&ioc->timer); | |
1921 | free_percpu(ioc->pcpu_stat); | |
1922 | kfree(ioc); | |
1923 | } | |
1924 | ||
1925 | static struct rq_qos_ops ioc_rqos_ops = { | |
1926 | .throttle = ioc_rqos_throttle, | |
1927 | .merge = ioc_rqos_merge, | |
1928 | .done_bio = ioc_rqos_done_bio, | |
1929 | .done = ioc_rqos_done, | |
1930 | .queue_depth_changed = ioc_rqos_queue_depth_changed, | |
1931 | .exit = ioc_rqos_exit, | |
1932 | }; | |
1933 | ||
1934 | static int blk_iocost_init(struct request_queue *q) | |
1935 | { | |
1936 | struct ioc *ioc; | |
1937 | struct rq_qos *rqos; | |
1938 | int ret; | |
1939 | ||
1940 | ioc = kzalloc(sizeof(*ioc), GFP_KERNEL); | |
1941 | if (!ioc) | |
1942 | return -ENOMEM; | |
1943 | ||
1944 | ioc->pcpu_stat = alloc_percpu(struct ioc_pcpu_stat); | |
1945 | if (!ioc->pcpu_stat) { | |
1946 | kfree(ioc); | |
1947 | return -ENOMEM; | |
1948 | } | |
1949 | ||
1950 | rqos = &ioc->rqos; | |
1951 | rqos->id = RQ_QOS_COST; | |
1952 | rqos->ops = &ioc_rqos_ops; | |
1953 | rqos->q = q; | |
1954 | ||
1955 | spin_lock_init(&ioc->lock); | |
1956 | timer_setup(&ioc->timer, ioc_timer_fn, 0); | |
1957 | INIT_LIST_HEAD(&ioc->active_iocgs); | |
1958 | ||
1959 | ioc->running = IOC_IDLE; | |
1960 | atomic64_set(&ioc->vtime_rate, VTIME_PER_USEC); | |
1961 | seqcount_init(&ioc->period_seqcount); | |
1962 | ioc->period_at = ktime_to_us(ktime_get()); | |
1963 | atomic64_set(&ioc->cur_period, 0); | |
1964 | atomic_set(&ioc->hweight_gen, 0); | |
1965 | ||
1966 | spin_lock_irq(&ioc->lock); | |
1967 | ioc->autop_idx = AUTOP_INVALID; | |
1968 | ioc_refresh_params(ioc, true); | |
1969 | spin_unlock_irq(&ioc->lock); | |
1970 | ||
1971 | rq_qos_add(q, rqos); | |
1972 | ret = blkcg_activate_policy(q, &blkcg_policy_iocost); | |
1973 | if (ret) { | |
1974 | rq_qos_del(q, rqos); | |
3532e722 | 1975 | free_percpu(ioc->pcpu_stat); |
7caa4715 TH |
1976 | kfree(ioc); |
1977 | return ret; | |
1978 | } | |
1979 | return 0; | |
1980 | } | |
1981 | ||
1982 | static struct blkcg_policy_data *ioc_cpd_alloc(gfp_t gfp) | |
1983 | { | |
1984 | struct ioc_cgrp *iocc; | |
1985 | ||
1986 | iocc = kzalloc(sizeof(struct ioc_cgrp), gfp); | |
e916ad29 TH |
1987 | if (!iocc) |
1988 | return NULL; | |
7caa4715 | 1989 | |
e916ad29 | 1990 | iocc->dfl_weight = CGROUP_WEIGHT_DFL; |
7caa4715 TH |
1991 | return &iocc->cpd; |
1992 | } | |
1993 | ||
1994 | static void ioc_cpd_free(struct blkcg_policy_data *cpd) | |
1995 | { | |
1996 | kfree(container_of(cpd, struct ioc_cgrp, cpd)); | |
1997 | } | |
1998 | ||
1999 | static struct blkg_policy_data *ioc_pd_alloc(gfp_t gfp, struct request_queue *q, | |
2000 | struct blkcg *blkcg) | |
2001 | { | |
2002 | int levels = blkcg->css.cgroup->level + 1; | |
2003 | struct ioc_gq *iocg; | |
2004 | ||
2005 | iocg = kzalloc_node(sizeof(*iocg) + levels * sizeof(iocg->ancestors[0]), | |
2006 | gfp, q->node); | |
2007 | if (!iocg) | |
2008 | return NULL; | |
2009 | ||
2010 | return &iocg->pd; | |
2011 | } | |
2012 | ||
2013 | static void ioc_pd_init(struct blkg_policy_data *pd) | |
2014 | { | |
2015 | struct ioc_gq *iocg = pd_to_iocg(pd); | |
2016 | struct blkcg_gq *blkg = pd_to_blkg(&iocg->pd); | |
2017 | struct ioc *ioc = q_to_ioc(blkg->q); | |
2018 | struct ioc_now now; | |
2019 | struct blkcg_gq *tblkg; | |
2020 | unsigned long flags; | |
2021 | ||
2022 | ioc_now(ioc, &now); | |
2023 | ||
2024 | iocg->ioc = ioc; | |
2025 | atomic64_set(&iocg->vtime, now.vnow); | |
2026 | atomic64_set(&iocg->done_vtime, now.vnow); | |
2027 | atomic64_set(&iocg->active_period, atomic64_read(&ioc->cur_period)); | |
2028 | INIT_LIST_HEAD(&iocg->active_list); | |
2029 | iocg->hweight_active = HWEIGHT_WHOLE; | |
2030 | iocg->hweight_inuse = HWEIGHT_WHOLE; | |
2031 | ||
2032 | init_waitqueue_head(&iocg->waitq); | |
2033 | hrtimer_init(&iocg->waitq_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS); | |
2034 | iocg->waitq_timer.function = iocg_waitq_timer_fn; | |
2035 | hrtimer_init(&iocg->delay_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS); | |
2036 | iocg->delay_timer.function = iocg_delay_timer_fn; | |
2037 | ||
2038 | iocg->level = blkg->blkcg->css.cgroup->level; | |
2039 | ||
2040 | for (tblkg = blkg; tblkg; tblkg = tblkg->parent) { | |
2041 | struct ioc_gq *tiocg = blkg_to_iocg(tblkg); | |
2042 | iocg->ancestors[tiocg->level] = tiocg; | |
2043 | } | |
2044 | ||
2045 | spin_lock_irqsave(&ioc->lock, flags); | |
2046 | weight_updated(iocg); | |
2047 | spin_unlock_irqrestore(&ioc->lock, flags); | |
2048 | } | |
2049 | ||
2050 | static void ioc_pd_free(struct blkg_policy_data *pd) | |
2051 | { | |
2052 | struct ioc_gq *iocg = pd_to_iocg(pd); | |
2053 | struct ioc *ioc = iocg->ioc; | |
2054 | ||
2055 | if (ioc) { | |
7caa4715 TH |
2056 | spin_lock(&ioc->lock); |
2057 | if (!list_empty(&iocg->active_list)) { | |
2058 | propagate_active_weight(iocg, 0, 0); | |
2059 | list_del_init(&iocg->active_list); | |
2060 | } | |
2061 | spin_unlock(&ioc->lock); | |
e036c4ca TH |
2062 | |
2063 | hrtimer_cancel(&iocg->waitq_timer); | |
2064 | hrtimer_cancel(&iocg->delay_timer); | |
7caa4715 TH |
2065 | } |
2066 | kfree(iocg); | |
2067 | } | |
2068 | ||
2069 | static u64 ioc_weight_prfill(struct seq_file *sf, struct blkg_policy_data *pd, | |
2070 | int off) | |
2071 | { | |
2072 | const char *dname = blkg_dev_name(pd->blkg); | |
2073 | struct ioc_gq *iocg = pd_to_iocg(pd); | |
2074 | ||
2075 | if (dname && iocg->cfg_weight) | |
2076 | seq_printf(sf, "%s %u\n", dname, iocg->cfg_weight); | |
2077 | return 0; | |
2078 | } | |
2079 | ||
2080 | ||
2081 | static int ioc_weight_show(struct seq_file *sf, void *v) | |
2082 | { | |
2083 | struct blkcg *blkcg = css_to_blkcg(seq_css(sf)); | |
2084 | struct ioc_cgrp *iocc = blkcg_to_iocc(blkcg); | |
2085 | ||
2086 | seq_printf(sf, "default %u\n", iocc->dfl_weight); | |
2087 | blkcg_print_blkgs(sf, blkcg, ioc_weight_prfill, | |
2088 | &blkcg_policy_iocost, seq_cft(sf)->private, false); | |
2089 | return 0; | |
2090 | } | |
2091 | ||
2092 | static ssize_t ioc_weight_write(struct kernfs_open_file *of, char *buf, | |
2093 | size_t nbytes, loff_t off) | |
2094 | { | |
2095 | struct blkcg *blkcg = css_to_blkcg(of_css(of)); | |
2096 | struct ioc_cgrp *iocc = blkcg_to_iocc(blkcg); | |
2097 | struct blkg_conf_ctx ctx; | |
2098 | struct ioc_gq *iocg; | |
2099 | u32 v; | |
2100 | int ret; | |
2101 | ||
2102 | if (!strchr(buf, ':')) { | |
2103 | struct blkcg_gq *blkg; | |
2104 | ||
2105 | if (!sscanf(buf, "default %u", &v) && !sscanf(buf, "%u", &v)) | |
2106 | return -EINVAL; | |
2107 | ||
2108 | if (v < CGROUP_WEIGHT_MIN || v > CGROUP_WEIGHT_MAX) | |
2109 | return -EINVAL; | |
2110 | ||
2111 | spin_lock(&blkcg->lock); | |
2112 | iocc->dfl_weight = v; | |
2113 | hlist_for_each_entry(blkg, &blkcg->blkg_list, blkcg_node) { | |
2114 | struct ioc_gq *iocg = blkg_to_iocg(blkg); | |
2115 | ||
2116 | if (iocg) { | |
2117 | spin_lock_irq(&iocg->ioc->lock); | |
2118 | weight_updated(iocg); | |
2119 | spin_unlock_irq(&iocg->ioc->lock); | |
2120 | } | |
2121 | } | |
2122 | spin_unlock(&blkcg->lock); | |
2123 | ||
2124 | return nbytes; | |
2125 | } | |
2126 | ||
2127 | ret = blkg_conf_prep(blkcg, &blkcg_policy_iocost, buf, &ctx); | |
2128 | if (ret) | |
2129 | return ret; | |
2130 | ||
2131 | iocg = blkg_to_iocg(ctx.blkg); | |
2132 | ||
2133 | if (!strncmp(ctx.body, "default", 7)) { | |
2134 | v = 0; | |
2135 | } else { | |
2136 | if (!sscanf(ctx.body, "%u", &v)) | |
2137 | goto einval; | |
2138 | if (v < CGROUP_WEIGHT_MIN || v > CGROUP_WEIGHT_MAX) | |
2139 | goto einval; | |
2140 | } | |
2141 | ||
41591a51 | 2142 | spin_lock(&iocg->ioc->lock); |
7caa4715 TH |
2143 | iocg->cfg_weight = v; |
2144 | weight_updated(iocg); | |
41591a51 | 2145 | spin_unlock(&iocg->ioc->lock); |
7caa4715 TH |
2146 | |
2147 | blkg_conf_finish(&ctx); | |
2148 | return nbytes; | |
2149 | ||
2150 | einval: | |
2151 | blkg_conf_finish(&ctx); | |
2152 | return -EINVAL; | |
2153 | } | |
2154 | ||
2155 | static u64 ioc_qos_prfill(struct seq_file *sf, struct blkg_policy_data *pd, | |
2156 | int off) | |
2157 | { | |
2158 | const char *dname = blkg_dev_name(pd->blkg); | |
2159 | struct ioc *ioc = pd_to_iocg(pd)->ioc; | |
2160 | ||
2161 | if (!dname) | |
2162 | return 0; | |
2163 | ||
2164 | 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", | |
2165 | dname, ioc->enabled, ioc->user_qos_params ? "user" : "auto", | |
2166 | ioc->params.qos[QOS_RPPM] / 10000, | |
2167 | ioc->params.qos[QOS_RPPM] % 10000 / 100, | |
2168 | ioc->params.qos[QOS_RLAT], | |
2169 | ioc->params.qos[QOS_WPPM] / 10000, | |
2170 | ioc->params.qos[QOS_WPPM] % 10000 / 100, | |
2171 | ioc->params.qos[QOS_WLAT], | |
2172 | ioc->params.qos[QOS_MIN] / 10000, | |
2173 | ioc->params.qos[QOS_MIN] % 10000 / 100, | |
2174 | ioc->params.qos[QOS_MAX] / 10000, | |
2175 | ioc->params.qos[QOS_MAX] % 10000 / 100); | |
2176 | return 0; | |
2177 | } | |
2178 | ||
2179 | static int ioc_qos_show(struct seq_file *sf, void *v) | |
2180 | { | |
2181 | struct blkcg *blkcg = css_to_blkcg(seq_css(sf)); | |
2182 | ||
2183 | blkcg_print_blkgs(sf, blkcg, ioc_qos_prfill, | |
2184 | &blkcg_policy_iocost, seq_cft(sf)->private, false); | |
2185 | return 0; | |
2186 | } | |
2187 | ||
2188 | static const match_table_t qos_ctrl_tokens = { | |
2189 | { QOS_ENABLE, "enable=%u" }, | |
2190 | { QOS_CTRL, "ctrl=%s" }, | |
2191 | { NR_QOS_CTRL_PARAMS, NULL }, | |
2192 | }; | |
2193 | ||
2194 | static const match_table_t qos_tokens = { | |
2195 | { QOS_RPPM, "rpct=%s" }, | |
2196 | { QOS_RLAT, "rlat=%u" }, | |
2197 | { QOS_WPPM, "wpct=%s" }, | |
2198 | { QOS_WLAT, "wlat=%u" }, | |
2199 | { QOS_MIN, "min=%s" }, | |
2200 | { QOS_MAX, "max=%s" }, | |
2201 | { NR_QOS_PARAMS, NULL }, | |
2202 | }; | |
2203 | ||
2204 | static ssize_t ioc_qos_write(struct kernfs_open_file *of, char *input, | |
2205 | size_t nbytes, loff_t off) | |
2206 | { | |
2207 | struct gendisk *disk; | |
2208 | struct ioc *ioc; | |
2209 | u32 qos[NR_QOS_PARAMS]; | |
2210 | bool enable, user; | |
2211 | char *p; | |
2212 | int ret; | |
2213 | ||
2214 | disk = blkcg_conf_get_disk(&input); | |
2215 | if (IS_ERR(disk)) | |
2216 | return PTR_ERR(disk); | |
2217 | ||
2218 | ioc = q_to_ioc(disk->queue); | |
2219 | if (!ioc) { | |
2220 | ret = blk_iocost_init(disk->queue); | |
2221 | if (ret) | |
2222 | goto err; | |
2223 | ioc = q_to_ioc(disk->queue); | |
2224 | } | |
2225 | ||
2226 | spin_lock_irq(&ioc->lock); | |
2227 | memcpy(qos, ioc->params.qos, sizeof(qos)); | |
2228 | enable = ioc->enabled; | |
2229 | user = ioc->user_qos_params; | |
2230 | spin_unlock_irq(&ioc->lock); | |
2231 | ||
2232 | while ((p = strsep(&input, " \t\n"))) { | |
2233 | substring_t args[MAX_OPT_ARGS]; | |
2234 | char buf[32]; | |
2235 | int tok; | |
2236 | s64 v; | |
2237 | ||
2238 | if (!*p) | |
2239 | continue; | |
2240 | ||
2241 | switch (match_token(p, qos_ctrl_tokens, args)) { | |
2242 | case QOS_ENABLE: | |
2243 | match_u64(&args[0], &v); | |
2244 | enable = v; | |
2245 | continue; | |
2246 | case QOS_CTRL: | |
2247 | match_strlcpy(buf, &args[0], sizeof(buf)); | |
2248 | if (!strcmp(buf, "auto")) | |
2249 | user = false; | |
2250 | else if (!strcmp(buf, "user")) | |
2251 | user = true; | |
2252 | else | |
2253 | goto einval; | |
2254 | continue; | |
2255 | } | |
2256 | ||
2257 | tok = match_token(p, qos_tokens, args); | |
2258 | switch (tok) { | |
2259 | case QOS_RPPM: | |
2260 | case QOS_WPPM: | |
2261 | if (match_strlcpy(buf, &args[0], sizeof(buf)) >= | |
2262 | sizeof(buf)) | |
2263 | goto einval; | |
2264 | if (cgroup_parse_float(buf, 2, &v)) | |
2265 | goto einval; | |
2266 | if (v < 0 || v > 10000) | |
2267 | goto einval; | |
2268 | qos[tok] = v * 100; | |
2269 | break; | |
2270 | case QOS_RLAT: | |
2271 | case QOS_WLAT: | |
2272 | if (match_u64(&args[0], &v)) | |
2273 | goto einval; | |
2274 | qos[tok] = v; | |
2275 | break; | |
2276 | case QOS_MIN: | |
2277 | case QOS_MAX: | |
2278 | if (match_strlcpy(buf, &args[0], sizeof(buf)) >= | |
2279 | sizeof(buf)) | |
2280 | goto einval; | |
2281 | if (cgroup_parse_float(buf, 2, &v)) | |
2282 | goto einval; | |
2283 | if (v < 0) | |
2284 | goto einval; | |
2285 | qos[tok] = clamp_t(s64, v * 100, | |
2286 | VRATE_MIN_PPM, VRATE_MAX_PPM); | |
2287 | break; | |
2288 | default: | |
2289 | goto einval; | |
2290 | } | |
2291 | user = true; | |
2292 | } | |
2293 | ||
2294 | if (qos[QOS_MIN] > qos[QOS_MAX]) | |
2295 | goto einval; | |
2296 | ||
2297 | spin_lock_irq(&ioc->lock); | |
2298 | ||
2299 | if (enable) { | |
2300 | blk_queue_flag_set(QUEUE_FLAG_RQ_ALLOC_TIME, ioc->rqos.q); | |
2301 | ioc->enabled = true; | |
2302 | } else { | |
2303 | blk_queue_flag_clear(QUEUE_FLAG_RQ_ALLOC_TIME, ioc->rqos.q); | |
2304 | ioc->enabled = false; | |
2305 | } | |
2306 | ||
2307 | if (user) { | |
2308 | memcpy(ioc->params.qos, qos, sizeof(qos)); | |
2309 | ioc->user_qos_params = true; | |
2310 | } else { | |
2311 | ioc->user_qos_params = false; | |
2312 | } | |
2313 | ||
2314 | ioc_refresh_params(ioc, true); | |
2315 | spin_unlock_irq(&ioc->lock); | |
2316 | ||
2317 | put_disk_and_module(disk); | |
2318 | return nbytes; | |
2319 | einval: | |
2320 | ret = -EINVAL; | |
2321 | err: | |
2322 | put_disk_and_module(disk); | |
2323 | return ret; | |
2324 | } | |
2325 | ||
2326 | static u64 ioc_cost_model_prfill(struct seq_file *sf, | |
2327 | struct blkg_policy_data *pd, int off) | |
2328 | { | |
2329 | const char *dname = blkg_dev_name(pd->blkg); | |
2330 | struct ioc *ioc = pd_to_iocg(pd)->ioc; | |
2331 | u64 *u = ioc->params.i_lcoefs; | |
2332 | ||
2333 | if (!dname) | |
2334 | return 0; | |
2335 | ||
2336 | seq_printf(sf, "%s ctrl=%s model=linear " | |
2337 | "rbps=%llu rseqiops=%llu rrandiops=%llu " | |
2338 | "wbps=%llu wseqiops=%llu wrandiops=%llu\n", | |
2339 | dname, ioc->user_cost_model ? "user" : "auto", | |
2340 | u[I_LCOEF_RBPS], u[I_LCOEF_RSEQIOPS], u[I_LCOEF_RRANDIOPS], | |
2341 | u[I_LCOEF_WBPS], u[I_LCOEF_WSEQIOPS], u[I_LCOEF_WRANDIOPS]); | |
2342 | return 0; | |
2343 | } | |
2344 | ||
2345 | static int ioc_cost_model_show(struct seq_file *sf, void *v) | |
2346 | { | |
2347 | struct blkcg *blkcg = css_to_blkcg(seq_css(sf)); | |
2348 | ||
2349 | blkcg_print_blkgs(sf, blkcg, ioc_cost_model_prfill, | |
2350 | &blkcg_policy_iocost, seq_cft(sf)->private, false); | |
2351 | return 0; | |
2352 | } | |
2353 | ||
2354 | static const match_table_t cost_ctrl_tokens = { | |
2355 | { COST_CTRL, "ctrl=%s" }, | |
2356 | { COST_MODEL, "model=%s" }, | |
2357 | { NR_COST_CTRL_PARAMS, NULL }, | |
2358 | }; | |
2359 | ||
2360 | static const match_table_t i_lcoef_tokens = { | |
2361 | { I_LCOEF_RBPS, "rbps=%u" }, | |
2362 | { I_LCOEF_RSEQIOPS, "rseqiops=%u" }, | |
2363 | { I_LCOEF_RRANDIOPS, "rrandiops=%u" }, | |
2364 | { I_LCOEF_WBPS, "wbps=%u" }, | |
2365 | { I_LCOEF_WSEQIOPS, "wseqiops=%u" }, | |
2366 | { I_LCOEF_WRANDIOPS, "wrandiops=%u" }, | |
2367 | { NR_I_LCOEFS, NULL }, | |
2368 | }; | |
2369 | ||
2370 | static ssize_t ioc_cost_model_write(struct kernfs_open_file *of, char *input, | |
2371 | size_t nbytes, loff_t off) | |
2372 | { | |
2373 | struct gendisk *disk; | |
2374 | struct ioc *ioc; | |
2375 | u64 u[NR_I_LCOEFS]; | |
2376 | bool user; | |
2377 | char *p; | |
2378 | int ret; | |
2379 | ||
2380 | disk = blkcg_conf_get_disk(&input); | |
2381 | if (IS_ERR(disk)) | |
2382 | return PTR_ERR(disk); | |
2383 | ||
2384 | ioc = q_to_ioc(disk->queue); | |
2385 | if (!ioc) { | |
2386 | ret = blk_iocost_init(disk->queue); | |
2387 | if (ret) | |
2388 | goto err; | |
2389 | ioc = q_to_ioc(disk->queue); | |
2390 | } | |
2391 | ||
2392 | spin_lock_irq(&ioc->lock); | |
2393 | memcpy(u, ioc->params.i_lcoefs, sizeof(u)); | |
2394 | user = ioc->user_cost_model; | |
2395 | spin_unlock_irq(&ioc->lock); | |
2396 | ||
2397 | while ((p = strsep(&input, " \t\n"))) { | |
2398 | substring_t args[MAX_OPT_ARGS]; | |
2399 | char buf[32]; | |
2400 | int tok; | |
2401 | u64 v; | |
2402 | ||
2403 | if (!*p) | |
2404 | continue; | |
2405 | ||
2406 | switch (match_token(p, cost_ctrl_tokens, args)) { | |
2407 | case COST_CTRL: | |
2408 | match_strlcpy(buf, &args[0], sizeof(buf)); | |
2409 | if (!strcmp(buf, "auto")) | |
2410 | user = false; | |
2411 | else if (!strcmp(buf, "user")) | |
2412 | user = true; | |
2413 | else | |
2414 | goto einval; | |
2415 | continue; | |
2416 | case COST_MODEL: | |
2417 | match_strlcpy(buf, &args[0], sizeof(buf)); | |
2418 | if (strcmp(buf, "linear")) | |
2419 | goto einval; | |
2420 | continue; | |
2421 | } | |
2422 | ||
2423 | tok = match_token(p, i_lcoef_tokens, args); | |
2424 | if (tok == NR_I_LCOEFS) | |
2425 | goto einval; | |
2426 | if (match_u64(&args[0], &v)) | |
2427 | goto einval; | |
2428 | u[tok] = v; | |
2429 | user = true; | |
2430 | } | |
2431 | ||
2432 | spin_lock_irq(&ioc->lock); | |
2433 | if (user) { | |
2434 | memcpy(ioc->params.i_lcoefs, u, sizeof(u)); | |
2435 | ioc->user_cost_model = true; | |
2436 | } else { | |
2437 | ioc->user_cost_model = false; | |
2438 | } | |
2439 | ioc_refresh_params(ioc, true); | |
2440 | spin_unlock_irq(&ioc->lock); | |
2441 | ||
2442 | put_disk_and_module(disk); | |
2443 | return nbytes; | |
2444 | ||
2445 | einval: | |
2446 | ret = -EINVAL; | |
2447 | err: | |
2448 | put_disk_and_module(disk); | |
2449 | return ret; | |
2450 | } | |
2451 | ||
2452 | static struct cftype ioc_files[] = { | |
2453 | { | |
2454 | .name = "weight", | |
2455 | .flags = CFTYPE_NOT_ON_ROOT, | |
2456 | .seq_show = ioc_weight_show, | |
2457 | .write = ioc_weight_write, | |
2458 | }, | |
2459 | { | |
2460 | .name = "cost.qos", | |
2461 | .flags = CFTYPE_ONLY_ON_ROOT, | |
2462 | .seq_show = ioc_qos_show, | |
2463 | .write = ioc_qos_write, | |
2464 | }, | |
2465 | { | |
2466 | .name = "cost.model", | |
2467 | .flags = CFTYPE_ONLY_ON_ROOT, | |
2468 | .seq_show = ioc_cost_model_show, | |
2469 | .write = ioc_cost_model_write, | |
2470 | }, | |
2471 | {} | |
2472 | }; | |
2473 | ||
2474 | static struct blkcg_policy blkcg_policy_iocost = { | |
2475 | .dfl_cftypes = ioc_files, | |
2476 | .cpd_alloc_fn = ioc_cpd_alloc, | |
2477 | .cpd_free_fn = ioc_cpd_free, | |
2478 | .pd_alloc_fn = ioc_pd_alloc, | |
2479 | .pd_init_fn = ioc_pd_init, | |
2480 | .pd_free_fn = ioc_pd_free, | |
2481 | }; | |
2482 | ||
2483 | static int __init ioc_init(void) | |
2484 | { | |
2485 | return blkcg_policy_register(&blkcg_policy_iocost); | |
2486 | } | |
2487 | ||
2488 | static void __exit ioc_exit(void) | |
2489 | { | |
2490 | return blkcg_policy_unregister(&blkcg_policy_iocost); | |
2491 | } | |
2492 | ||
2493 | module_init(ioc_init); | |
2494 | module_exit(ioc_exit); |