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3b1a94c8 DLM |
1 | /* |
2 | * Copyright (C) 2017 Western Digital Corporation or its affiliates. | |
3 | * | |
4 | * This file is released under the GPL. | |
5 | */ | |
6 | ||
7 | #include "dm-zoned.h" | |
8 | ||
9 | #include <linux/module.h> | |
10 | ||
11 | #define DM_MSG_PREFIX "zoned reclaim" | |
12 | ||
13 | struct dmz_reclaim { | |
14 | struct dmz_metadata *metadata; | |
15 | struct dmz_dev *dev; | |
16 | ||
17 | struct delayed_work work; | |
18 | struct workqueue_struct *wq; | |
19 | ||
20 | struct dm_kcopyd_client *kc; | |
21 | struct dm_kcopyd_throttle kc_throttle; | |
22 | int kc_err; | |
23 | ||
24 | unsigned long flags; | |
25 | ||
26 | /* Last target access time */ | |
27 | unsigned long atime; | |
28 | }; | |
29 | ||
30 | /* | |
31 | * Reclaim state flags. | |
32 | */ | |
33 | enum { | |
34 | DMZ_RECLAIM_KCOPY, | |
35 | }; | |
36 | ||
37 | /* | |
38 | * Number of seconds of target BIO inactivity to consider the target idle. | |
39 | */ | |
40 | #define DMZ_IDLE_PERIOD (10UL * HZ) | |
41 | ||
42 | /* | |
43 | * Percentage of unmapped (free) random zones below which reclaim starts | |
44 | * even if the target is busy. | |
45 | */ | |
46 | #define DMZ_RECLAIM_LOW_UNMAP_RND 30 | |
47 | ||
48 | /* | |
49 | * Percentage of unmapped (free) random zones above which reclaim will | |
50 | * stop if the target is busy. | |
51 | */ | |
52 | #define DMZ_RECLAIM_HIGH_UNMAP_RND 50 | |
53 | ||
54 | /* | |
55 | * Align a sequential zone write pointer to chunk_block. | |
56 | */ | |
57 | static int dmz_reclaim_align_wp(struct dmz_reclaim *zrc, struct dm_zone *zone, | |
58 | sector_t block) | |
59 | { | |
60 | struct dmz_metadata *zmd = zrc->metadata; | |
61 | sector_t wp_block = zone->wp_block; | |
62 | unsigned int nr_blocks; | |
63 | int ret; | |
64 | ||
65 | if (wp_block == block) | |
66 | return 0; | |
67 | ||
68 | if (wp_block > block) | |
69 | return -EIO; | |
70 | ||
71 | /* | |
72 | * Zeroout the space between the write | |
73 | * pointer and the requested position. | |
74 | */ | |
75 | nr_blocks = block - wp_block; | |
76 | ret = blkdev_issue_zeroout(zrc->dev->bdev, | |
77 | dmz_start_sect(zmd, zone) + dmz_blk2sect(wp_block), | |
4218a955 | 78 | dmz_blk2sect(nr_blocks), GFP_NOIO, 0); |
3b1a94c8 DLM |
79 | if (ret) { |
80 | dmz_dev_err(zrc->dev, | |
81 | "Align zone %u wp %llu to %llu (wp+%u) blocks failed %d", | |
82 | dmz_id(zmd, zone), (unsigned long long)wp_block, | |
83 | (unsigned long long)block, nr_blocks, ret); | |
84 | return ret; | |
85 | } | |
86 | ||
87 | zone->wp_block = block; | |
88 | ||
89 | return 0; | |
90 | } | |
91 | ||
92 | /* | |
93 | * dm_kcopyd_copy end notification. | |
94 | */ | |
95 | static void dmz_reclaim_kcopy_end(int read_err, unsigned long write_err, | |
96 | void *context) | |
97 | { | |
98 | struct dmz_reclaim *zrc = context; | |
99 | ||
100 | if (read_err || write_err) | |
101 | zrc->kc_err = -EIO; | |
102 | else | |
103 | zrc->kc_err = 0; | |
104 | ||
105 | clear_bit_unlock(DMZ_RECLAIM_KCOPY, &zrc->flags); | |
106 | smp_mb__after_atomic(); | |
107 | wake_up_bit(&zrc->flags, DMZ_RECLAIM_KCOPY); | |
108 | } | |
109 | ||
110 | /* | |
111 | * Copy valid blocks of src_zone into dst_zone. | |
112 | */ | |
113 | static int dmz_reclaim_copy(struct dmz_reclaim *zrc, | |
114 | struct dm_zone *src_zone, struct dm_zone *dst_zone) | |
115 | { | |
116 | struct dmz_metadata *zmd = zrc->metadata; | |
117 | struct dmz_dev *dev = zrc->dev; | |
118 | struct dm_io_region src, dst; | |
119 | sector_t block = 0, end_block; | |
120 | sector_t nr_blocks; | |
121 | sector_t src_zone_block; | |
122 | sector_t dst_zone_block; | |
123 | unsigned long flags = 0; | |
124 | int ret; | |
125 | ||
126 | if (dmz_is_seq(src_zone)) | |
127 | end_block = src_zone->wp_block; | |
128 | else | |
129 | end_block = dev->zone_nr_blocks; | |
130 | src_zone_block = dmz_start_block(zmd, src_zone); | |
131 | dst_zone_block = dmz_start_block(zmd, dst_zone); | |
132 | ||
133 | if (dmz_is_seq(dst_zone)) | |
134 | set_bit(DM_KCOPYD_WRITE_SEQ, &flags); | |
135 | ||
136 | while (block < end_block) { | |
137 | /* Get a valid region from the source zone */ | |
138 | ret = dmz_first_valid_block(zmd, src_zone, &block); | |
139 | if (ret <= 0) | |
140 | return ret; | |
141 | nr_blocks = ret; | |
142 | ||
143 | /* | |
144 | * If we are writing in a sequential zone, we must make sure | |
145 | * that writes are sequential. So Zeroout any eventual hole | |
146 | * between writes. | |
147 | */ | |
148 | if (dmz_is_seq(dst_zone)) { | |
149 | ret = dmz_reclaim_align_wp(zrc, dst_zone, block); | |
150 | if (ret) | |
151 | return ret; | |
152 | } | |
153 | ||
154 | src.bdev = dev->bdev; | |
155 | src.sector = dmz_blk2sect(src_zone_block + block); | |
156 | src.count = dmz_blk2sect(nr_blocks); | |
157 | ||
158 | dst.bdev = dev->bdev; | |
159 | dst.sector = dmz_blk2sect(dst_zone_block + block); | |
160 | dst.count = src.count; | |
161 | ||
162 | /* Copy the valid region */ | |
163 | set_bit(DMZ_RECLAIM_KCOPY, &zrc->flags); | |
164 | ret = dm_kcopyd_copy(zrc->kc, &src, 1, &dst, flags, | |
165 | dmz_reclaim_kcopy_end, zrc); | |
166 | if (ret) | |
167 | return ret; | |
168 | ||
169 | /* Wait for copy to complete */ | |
170 | wait_on_bit_io(&zrc->flags, DMZ_RECLAIM_KCOPY, | |
171 | TASK_UNINTERRUPTIBLE); | |
172 | if (zrc->kc_err) | |
173 | return zrc->kc_err; | |
174 | ||
175 | block += nr_blocks; | |
176 | if (dmz_is_seq(dst_zone)) | |
177 | dst_zone->wp_block = block; | |
178 | } | |
179 | ||
180 | return 0; | |
181 | } | |
182 | ||
183 | /* | |
184 | * Move valid blocks of dzone buffer zone into dzone (after its write pointer) | |
185 | * and free the buffer zone. | |
186 | */ | |
187 | static int dmz_reclaim_buf(struct dmz_reclaim *zrc, struct dm_zone *dzone) | |
188 | { | |
189 | struct dm_zone *bzone = dzone->bzone; | |
190 | sector_t chunk_block = dzone->wp_block; | |
191 | struct dmz_metadata *zmd = zrc->metadata; | |
192 | int ret; | |
193 | ||
194 | dmz_dev_debug(zrc->dev, | |
195 | "Chunk %u, move buf zone %u (weight %u) to data zone %u (weight %u)", | |
196 | dzone->chunk, dmz_id(zmd, bzone), dmz_weight(bzone), | |
197 | dmz_id(zmd, dzone), dmz_weight(dzone)); | |
198 | ||
199 | /* Flush data zone into the buffer zone */ | |
200 | ret = dmz_reclaim_copy(zrc, bzone, dzone); | |
201 | if (ret < 0) | |
202 | return ret; | |
203 | ||
204 | dmz_lock_flush(zmd); | |
205 | ||
206 | /* Validate copied blocks */ | |
207 | ret = dmz_merge_valid_blocks(zmd, bzone, dzone, chunk_block); | |
208 | if (ret == 0) { | |
209 | /* Free the buffer zone */ | |
210 | dmz_invalidate_blocks(zmd, bzone, 0, zrc->dev->zone_nr_blocks); | |
211 | dmz_lock_map(zmd); | |
212 | dmz_unmap_zone(zmd, bzone); | |
213 | dmz_unlock_zone_reclaim(dzone); | |
214 | dmz_free_zone(zmd, bzone); | |
215 | dmz_unlock_map(zmd); | |
216 | } | |
217 | ||
218 | dmz_unlock_flush(zmd); | |
219 | ||
220 | return 0; | |
221 | } | |
222 | ||
223 | /* | |
224 | * Merge valid blocks of dzone into its buffer zone and free dzone. | |
225 | */ | |
226 | static int dmz_reclaim_seq_data(struct dmz_reclaim *zrc, struct dm_zone *dzone) | |
227 | { | |
228 | unsigned int chunk = dzone->chunk; | |
229 | struct dm_zone *bzone = dzone->bzone; | |
230 | struct dmz_metadata *zmd = zrc->metadata; | |
231 | int ret = 0; | |
232 | ||
233 | dmz_dev_debug(zrc->dev, | |
234 | "Chunk %u, move data zone %u (weight %u) to buf zone %u (weight %u)", | |
235 | chunk, dmz_id(zmd, dzone), dmz_weight(dzone), | |
236 | dmz_id(zmd, bzone), dmz_weight(bzone)); | |
237 | ||
238 | /* Flush data zone into the buffer zone */ | |
239 | ret = dmz_reclaim_copy(zrc, dzone, bzone); | |
240 | if (ret < 0) | |
241 | return ret; | |
242 | ||
243 | dmz_lock_flush(zmd); | |
244 | ||
245 | /* Validate copied blocks */ | |
246 | ret = dmz_merge_valid_blocks(zmd, dzone, bzone, 0); | |
247 | if (ret == 0) { | |
248 | /* | |
249 | * Free the data zone and remap the chunk to | |
250 | * the buffer zone. | |
251 | */ | |
252 | dmz_invalidate_blocks(zmd, dzone, 0, zrc->dev->zone_nr_blocks); | |
253 | dmz_lock_map(zmd); | |
254 | dmz_unmap_zone(zmd, bzone); | |
255 | dmz_unmap_zone(zmd, dzone); | |
256 | dmz_unlock_zone_reclaim(dzone); | |
257 | dmz_free_zone(zmd, dzone); | |
258 | dmz_map_zone(zmd, bzone, chunk); | |
259 | dmz_unlock_map(zmd); | |
260 | } | |
261 | ||
262 | dmz_unlock_flush(zmd); | |
263 | ||
264 | return 0; | |
265 | } | |
266 | ||
267 | /* | |
268 | * Move valid blocks of the random data zone dzone into a free sequential zone. | |
269 | * Once blocks are moved, remap the zone chunk to the sequential zone. | |
270 | */ | |
271 | static int dmz_reclaim_rnd_data(struct dmz_reclaim *zrc, struct dm_zone *dzone) | |
272 | { | |
273 | unsigned int chunk = dzone->chunk; | |
274 | struct dm_zone *szone = NULL; | |
275 | struct dmz_metadata *zmd = zrc->metadata; | |
276 | int ret; | |
277 | ||
278 | /* Get a free sequential zone */ | |
279 | dmz_lock_map(zmd); | |
280 | szone = dmz_alloc_zone(zmd, DMZ_ALLOC_RECLAIM); | |
281 | dmz_unlock_map(zmd); | |
282 | if (!szone) | |
283 | return -ENOSPC; | |
284 | ||
285 | dmz_dev_debug(zrc->dev, | |
286 | "Chunk %u, move rnd zone %u (weight %u) to seq zone %u", | |
287 | chunk, dmz_id(zmd, dzone), dmz_weight(dzone), | |
288 | dmz_id(zmd, szone)); | |
289 | ||
290 | /* Flush the random data zone into the sequential zone */ | |
291 | ret = dmz_reclaim_copy(zrc, dzone, szone); | |
292 | ||
293 | dmz_lock_flush(zmd); | |
294 | ||
295 | if (ret == 0) { | |
296 | /* Validate copied blocks */ | |
297 | ret = dmz_copy_valid_blocks(zmd, dzone, szone); | |
298 | } | |
299 | if (ret) { | |
300 | /* Free the sequential zone */ | |
301 | dmz_lock_map(zmd); | |
302 | dmz_free_zone(zmd, szone); | |
303 | dmz_unlock_map(zmd); | |
304 | } else { | |
305 | /* Free the data zone and remap the chunk */ | |
306 | dmz_invalidate_blocks(zmd, dzone, 0, zrc->dev->zone_nr_blocks); | |
307 | dmz_lock_map(zmd); | |
308 | dmz_unmap_zone(zmd, dzone); | |
309 | dmz_unlock_zone_reclaim(dzone); | |
310 | dmz_free_zone(zmd, dzone); | |
311 | dmz_map_zone(zmd, szone, chunk); | |
312 | dmz_unlock_map(zmd); | |
313 | } | |
314 | ||
315 | dmz_unlock_flush(zmd); | |
316 | ||
317 | return 0; | |
318 | } | |
319 | ||
320 | /* | |
321 | * Reclaim an empty zone. | |
322 | */ | |
323 | static void dmz_reclaim_empty(struct dmz_reclaim *zrc, struct dm_zone *dzone) | |
324 | { | |
325 | struct dmz_metadata *zmd = zrc->metadata; | |
326 | ||
327 | dmz_lock_flush(zmd); | |
328 | dmz_lock_map(zmd); | |
329 | dmz_unmap_zone(zmd, dzone); | |
330 | dmz_unlock_zone_reclaim(dzone); | |
331 | dmz_free_zone(zmd, dzone); | |
332 | dmz_unlock_map(zmd); | |
333 | dmz_unlock_flush(zmd); | |
334 | } | |
335 | ||
336 | /* | |
337 | * Find a candidate zone for reclaim and process it. | |
338 | */ | |
339 | static void dmz_reclaim(struct dmz_reclaim *zrc) | |
340 | { | |
341 | struct dmz_metadata *zmd = zrc->metadata; | |
342 | struct dm_zone *dzone; | |
343 | struct dm_zone *rzone; | |
344 | unsigned long start; | |
345 | int ret; | |
346 | ||
347 | /* Get a data zone */ | |
348 | dzone = dmz_get_zone_for_reclaim(zmd); | |
349 | if (!dzone) | |
350 | return; | |
351 | ||
352 | start = jiffies; | |
353 | ||
354 | if (dmz_is_rnd(dzone)) { | |
355 | if (!dmz_weight(dzone)) { | |
356 | /* Empty zone */ | |
357 | dmz_reclaim_empty(zrc, dzone); | |
358 | ret = 0; | |
359 | } else { | |
360 | /* | |
361 | * Reclaim the random data zone by moving its | |
362 | * valid data blocks to a free sequential zone. | |
363 | */ | |
364 | ret = dmz_reclaim_rnd_data(zrc, dzone); | |
365 | } | |
366 | rzone = dzone; | |
367 | ||
368 | } else { | |
369 | struct dm_zone *bzone = dzone->bzone; | |
370 | sector_t chunk_block = 0; | |
371 | ||
372 | ret = dmz_first_valid_block(zmd, bzone, &chunk_block); | |
373 | if (ret < 0) | |
374 | goto out; | |
375 | ||
376 | if (ret == 0 || chunk_block >= dzone->wp_block) { | |
377 | /* | |
378 | * The buffer zone is empty or its valid blocks are | |
379 | * after the data zone write pointer. | |
380 | */ | |
381 | ret = dmz_reclaim_buf(zrc, dzone); | |
382 | rzone = bzone; | |
383 | } else { | |
384 | /* | |
385 | * Reclaim the data zone by merging it into the | |
386 | * buffer zone so that the buffer zone itself can | |
387 | * be later reclaimed. | |
388 | */ | |
389 | ret = dmz_reclaim_seq_data(zrc, dzone); | |
390 | rzone = dzone; | |
391 | } | |
392 | } | |
393 | out: | |
394 | if (ret) { | |
395 | dmz_unlock_zone_reclaim(dzone); | |
396 | return; | |
397 | } | |
398 | ||
399 | (void) dmz_flush_metadata(zrc->metadata); | |
400 | ||
401 | dmz_dev_debug(zrc->dev, "Reclaimed zone %u in %u ms", | |
402 | dmz_id(zmd, rzone), jiffies_to_msecs(jiffies - start)); | |
403 | } | |
404 | ||
405 | /* | |
406 | * Test if the target device is idle. | |
407 | */ | |
408 | static inline int dmz_target_idle(struct dmz_reclaim *zrc) | |
409 | { | |
410 | return time_is_before_jiffies(zrc->atime + DMZ_IDLE_PERIOD); | |
411 | } | |
412 | ||
413 | /* | |
414 | * Test if reclaim is necessary. | |
415 | */ | |
416 | static bool dmz_should_reclaim(struct dmz_reclaim *zrc) | |
417 | { | |
418 | struct dmz_metadata *zmd = zrc->metadata; | |
419 | unsigned int nr_rnd = dmz_nr_rnd_zones(zmd); | |
420 | unsigned int nr_unmap_rnd = dmz_nr_unmap_rnd_zones(zmd); | |
421 | unsigned int p_unmap_rnd = nr_unmap_rnd * 100 / nr_rnd; | |
422 | ||
423 | /* Reclaim when idle */ | |
424 | if (dmz_target_idle(zrc) && nr_unmap_rnd < nr_rnd) | |
425 | return true; | |
426 | ||
427 | /* If there are still plenty of random zones, do not reclaim */ | |
428 | if (p_unmap_rnd >= DMZ_RECLAIM_HIGH_UNMAP_RND) | |
429 | return false; | |
430 | ||
431 | /* | |
432 | * If the percentage of unmappped random zones is low, | |
433 | * reclaim even if the target is busy. | |
434 | */ | |
435 | return p_unmap_rnd <= DMZ_RECLAIM_LOW_UNMAP_RND; | |
436 | } | |
437 | ||
438 | /* | |
439 | * Reclaim work function. | |
440 | */ | |
441 | static void dmz_reclaim_work(struct work_struct *work) | |
442 | { | |
443 | struct dmz_reclaim *zrc = container_of(work, struct dmz_reclaim, work.work); | |
444 | struct dmz_metadata *zmd = zrc->metadata; | |
445 | unsigned int nr_rnd, nr_unmap_rnd; | |
446 | unsigned int p_unmap_rnd; | |
447 | ||
448 | if (!dmz_should_reclaim(zrc)) { | |
449 | mod_delayed_work(zrc->wq, &zrc->work, DMZ_IDLE_PERIOD); | |
450 | return; | |
451 | } | |
452 | ||
453 | /* | |
454 | * We need to start reclaiming random zones: set up zone copy | |
455 | * throttling to either go fast if we are very low on random zones | |
456 | * and slower if there are still some free random zones to avoid | |
457 | * as much as possible to negatively impact the user workload. | |
458 | */ | |
459 | nr_rnd = dmz_nr_rnd_zones(zmd); | |
460 | nr_unmap_rnd = dmz_nr_unmap_rnd_zones(zmd); | |
461 | p_unmap_rnd = nr_unmap_rnd * 100 / nr_rnd; | |
462 | if (dmz_target_idle(zrc) || p_unmap_rnd < DMZ_RECLAIM_LOW_UNMAP_RND / 2) { | |
463 | /* Idle or very low percentage: go fast */ | |
464 | zrc->kc_throttle.throttle = 100; | |
465 | } else { | |
466 | /* Busy but we still have some random zone: throttle */ | |
467 | zrc->kc_throttle.throttle = min(75U, 100U - p_unmap_rnd / 2); | |
468 | } | |
469 | ||
470 | dmz_dev_debug(zrc->dev, | |
471 | "Reclaim (%u): %s, %u%% free rnd zones (%u/%u)", | |
472 | zrc->kc_throttle.throttle, | |
473 | (dmz_target_idle(zrc) ? "Idle" : "Busy"), | |
474 | p_unmap_rnd, nr_unmap_rnd, nr_rnd); | |
475 | ||
476 | dmz_reclaim(zrc); | |
477 | ||
478 | dmz_schedule_reclaim(zrc); | |
479 | } | |
480 | ||
481 | /* | |
482 | * Initialize reclaim. | |
483 | */ | |
484 | int dmz_ctr_reclaim(struct dmz_dev *dev, struct dmz_metadata *zmd, | |
485 | struct dmz_reclaim **reclaim) | |
486 | { | |
487 | struct dmz_reclaim *zrc; | |
488 | int ret; | |
489 | ||
490 | zrc = kzalloc(sizeof(struct dmz_reclaim), GFP_KERNEL); | |
491 | if (!zrc) | |
492 | return -ENOMEM; | |
493 | ||
494 | zrc->dev = dev; | |
495 | zrc->metadata = zmd; | |
496 | zrc->atime = jiffies; | |
497 | ||
498 | /* Reclaim kcopyd client */ | |
499 | zrc->kc = dm_kcopyd_client_create(&zrc->kc_throttle); | |
500 | if (IS_ERR(zrc->kc)) { | |
501 | ret = PTR_ERR(zrc->kc); | |
502 | zrc->kc = NULL; | |
503 | goto err; | |
504 | } | |
505 | ||
506 | /* Reclaim work */ | |
507 | INIT_DELAYED_WORK(&zrc->work, dmz_reclaim_work); | |
508 | zrc->wq = alloc_ordered_workqueue("dmz_rwq_%s", WQ_MEM_RECLAIM, | |
509 | dev->name); | |
510 | if (!zrc->wq) { | |
511 | ret = -ENOMEM; | |
512 | goto err; | |
513 | } | |
514 | ||
515 | *reclaim = zrc; | |
516 | queue_delayed_work(zrc->wq, &zrc->work, 0); | |
517 | ||
518 | return 0; | |
519 | err: | |
520 | if (zrc->kc) | |
521 | dm_kcopyd_client_destroy(zrc->kc); | |
522 | kfree(zrc); | |
523 | ||
524 | return ret; | |
525 | } | |
526 | ||
527 | /* | |
528 | * Terminate reclaim. | |
529 | */ | |
530 | void dmz_dtr_reclaim(struct dmz_reclaim *zrc) | |
531 | { | |
532 | cancel_delayed_work_sync(&zrc->work); | |
533 | destroy_workqueue(zrc->wq); | |
534 | dm_kcopyd_client_destroy(zrc->kc); | |
535 | kfree(zrc); | |
536 | } | |
537 | ||
538 | /* | |
539 | * Suspend reclaim. | |
540 | */ | |
541 | void dmz_suspend_reclaim(struct dmz_reclaim *zrc) | |
542 | { | |
543 | cancel_delayed_work_sync(&zrc->work); | |
544 | } | |
545 | ||
546 | /* | |
547 | * Resume reclaim. | |
548 | */ | |
549 | void dmz_resume_reclaim(struct dmz_reclaim *zrc) | |
550 | { | |
551 | queue_delayed_work(zrc->wq, &zrc->work, DMZ_IDLE_PERIOD); | |
552 | } | |
553 | ||
554 | /* | |
555 | * BIO accounting. | |
556 | */ | |
557 | void dmz_reclaim_bio_acc(struct dmz_reclaim *zrc) | |
558 | { | |
559 | zrc->atime = jiffies; | |
560 | } | |
561 | ||
562 | /* | |
563 | * Start reclaim if necessary. | |
564 | */ | |
565 | void dmz_schedule_reclaim(struct dmz_reclaim *zrc) | |
566 | { | |
567 | if (dmz_should_reclaim(zrc)) | |
568 | mod_delayed_work(zrc->wq, &zrc->work, 0); | |
569 | } | |
570 |