1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2017 Western Digital Corporation or its affiliates.
5 * This file is released under the GPL.
10 #include <linux/module.h>
12 #define DM_MSG_PREFIX "zoned reclaim"
15 struct dmz_metadata *metadata;
17 struct delayed_work work;
18 struct workqueue_struct *wq;
20 struct dm_kcopyd_client *kc;
21 struct dm_kcopyd_throttle kc_throttle;
28 /* Last target access time */
33 * Reclaim state flags.
40 * Number of seconds of target BIO inactivity to consider the target idle.
42 #define DMZ_IDLE_PERIOD (10UL * HZ)
45 * Percentage of unmapped (free) random zones below which reclaim starts
46 * even if the target is busy.
48 #define DMZ_RECLAIM_LOW_UNMAP_ZONES 30
51 * Percentage of unmapped (free) random zones above which reclaim will
52 * stop if the target is busy.
54 #define DMZ_RECLAIM_HIGH_UNMAP_ZONES 50
57 * Align a sequential zone write pointer to chunk_block.
59 static int dmz_reclaim_align_wp(struct dmz_reclaim *zrc, struct dm_zone *zone,
62 struct dmz_metadata *zmd = zrc->metadata;
63 struct dmz_dev *dev = zone->dev;
64 sector_t wp_block = zone->wp_block;
65 unsigned int nr_blocks;
68 if (wp_block == block)
75 * Zeroout the space between the write
76 * pointer and the requested position.
78 nr_blocks = block - wp_block;
79 ret = blkdev_issue_zeroout(dev->bdev,
80 dmz_start_sect(zmd, zone) + dmz_blk2sect(wp_block),
81 dmz_blk2sect(nr_blocks), GFP_NOIO, 0);
84 "Align zone %u wp %llu to %llu (wp+%u) blocks failed %d",
85 zone->id, (unsigned long long)wp_block,
86 (unsigned long long)block, nr_blocks, ret);
91 zone->wp_block = block;
97 * dm_kcopyd_copy end notification.
99 static void dmz_reclaim_kcopy_end(int read_err, unsigned long write_err,
102 struct dmz_reclaim *zrc = context;
104 if (read_err || write_err)
109 clear_bit_unlock(DMZ_RECLAIM_KCOPY, &zrc->flags);
110 smp_mb__after_atomic();
111 wake_up_bit(&zrc->flags, DMZ_RECLAIM_KCOPY);
115 * Copy valid blocks of src_zone into dst_zone.
117 static int dmz_reclaim_copy(struct dmz_reclaim *zrc,
118 struct dm_zone *src_zone, struct dm_zone *dst_zone)
120 struct dmz_metadata *zmd = zrc->metadata;
121 struct dm_io_region src, dst;
122 sector_t block = 0, end_block;
124 sector_t src_zone_block;
125 sector_t dst_zone_block;
126 unsigned long flags = 0;
129 if (dmz_is_seq(src_zone))
130 end_block = src_zone->wp_block;
132 end_block = dmz_zone_nr_blocks(zmd);
133 src_zone_block = dmz_start_block(zmd, src_zone);
134 dst_zone_block = dmz_start_block(zmd, dst_zone);
136 if (dmz_is_seq(dst_zone))
137 flags |= BIT(DM_KCOPYD_WRITE_SEQ);
139 while (block < end_block) {
140 if (src_zone->dev->flags & DMZ_BDEV_DYING)
142 if (dst_zone->dev->flags & DMZ_BDEV_DYING)
145 if (dmz_reclaim_should_terminate(src_zone))
148 /* Get a valid region from the source zone */
149 ret = dmz_first_valid_block(zmd, src_zone, &block);
155 * If we are writing in a sequential zone, we must make sure
156 * that writes are sequential. So Zeroout any eventual hole
159 if (dmz_is_seq(dst_zone)) {
160 ret = dmz_reclaim_align_wp(zrc, dst_zone, block);
165 src.bdev = src_zone->dev->bdev;
166 src.sector = dmz_blk2sect(src_zone_block + block);
167 src.count = dmz_blk2sect(nr_blocks);
169 dst.bdev = dst_zone->dev->bdev;
170 dst.sector = dmz_blk2sect(dst_zone_block + block);
171 dst.count = src.count;
173 /* Copy the valid region */
174 set_bit(DMZ_RECLAIM_KCOPY, &zrc->flags);
175 dm_kcopyd_copy(zrc->kc, &src, 1, &dst, flags,
176 dmz_reclaim_kcopy_end, zrc);
178 /* Wait for copy to complete */
179 wait_on_bit_io(&zrc->flags, DMZ_RECLAIM_KCOPY,
180 TASK_UNINTERRUPTIBLE);
185 if (dmz_is_seq(dst_zone))
186 dst_zone->wp_block = block;
193 * Move valid blocks of dzone buffer zone into dzone (after its write pointer)
194 * and free the buffer zone.
196 static int dmz_reclaim_buf(struct dmz_reclaim *zrc, struct dm_zone *dzone)
198 struct dm_zone *bzone = dzone->bzone;
199 sector_t chunk_block = dzone->wp_block;
200 struct dmz_metadata *zmd = zrc->metadata;
203 DMDEBUG("(%s/%u): Chunk %u, move buf zone %u (weight %u) to data zone %u (weight %u)",
204 dmz_metadata_label(zmd), zrc->dev_idx,
205 dzone->chunk, bzone->id, dmz_weight(bzone),
206 dzone->id, dmz_weight(dzone));
208 /* Flush data zone into the buffer zone */
209 ret = dmz_reclaim_copy(zrc, bzone, dzone);
215 /* Validate copied blocks */
216 ret = dmz_merge_valid_blocks(zmd, bzone, dzone, chunk_block);
218 /* Free the buffer zone */
219 dmz_invalidate_blocks(zmd, bzone, 0, dmz_zone_nr_blocks(zmd));
221 dmz_unmap_zone(zmd, bzone);
222 dmz_unlock_zone_reclaim(dzone);
223 dmz_free_zone(zmd, bzone);
227 dmz_unlock_flush(zmd);
233 * Merge valid blocks of dzone into its buffer zone and free dzone.
235 static int dmz_reclaim_seq_data(struct dmz_reclaim *zrc, struct dm_zone *dzone)
237 unsigned int chunk = dzone->chunk;
238 struct dm_zone *bzone = dzone->bzone;
239 struct dmz_metadata *zmd = zrc->metadata;
242 DMDEBUG("(%s/%u): Chunk %u, move data zone %u (weight %u) to buf zone %u (weight %u)",
243 dmz_metadata_label(zmd), zrc->dev_idx,
244 chunk, dzone->id, dmz_weight(dzone),
245 bzone->id, dmz_weight(bzone));
247 /* Flush data zone into the buffer zone */
248 ret = dmz_reclaim_copy(zrc, dzone, bzone);
254 /* Validate copied blocks */
255 ret = dmz_merge_valid_blocks(zmd, dzone, bzone, 0);
258 * Free the data zone and remap the chunk to
261 dmz_invalidate_blocks(zmd, dzone, 0, dmz_zone_nr_blocks(zmd));
263 dmz_unmap_zone(zmd, bzone);
264 dmz_unmap_zone(zmd, dzone);
265 dmz_unlock_zone_reclaim(dzone);
266 dmz_free_zone(zmd, dzone);
267 dmz_map_zone(zmd, bzone, chunk);
271 dmz_unlock_flush(zmd);
277 * Move valid blocks of the random data zone dzone into a free sequential zone.
278 * Once blocks are moved, remap the zone chunk to the sequential zone.
280 static int dmz_reclaim_rnd_data(struct dmz_reclaim *zrc, struct dm_zone *dzone)
282 unsigned int chunk = dzone->chunk;
283 struct dm_zone *szone = NULL;
284 struct dmz_metadata *zmd = zrc->metadata;
286 int alloc_flags = DMZ_ALLOC_SEQ;
288 /* Get a free random or sequential zone */
291 szone = dmz_alloc_zone(zmd, zrc->dev_idx,
292 alloc_flags | DMZ_ALLOC_RECLAIM);
293 if (!szone && alloc_flags == DMZ_ALLOC_SEQ && dmz_nr_cache_zones(zmd)) {
294 alloc_flags = DMZ_ALLOC_RND;
301 DMDEBUG("(%s/%u): Chunk %u, move %s zone %u (weight %u) to %s zone %u",
302 dmz_metadata_label(zmd), zrc->dev_idx, chunk,
303 dmz_is_cache(dzone) ? "cache" : "rnd",
304 dzone->id, dmz_weight(dzone),
305 dmz_is_rnd(szone) ? "rnd" : "seq", szone->id);
307 /* Flush the random data zone into the sequential zone */
308 ret = dmz_reclaim_copy(zrc, dzone, szone);
313 /* Validate copied blocks */
314 ret = dmz_copy_valid_blocks(zmd, dzone, szone);
317 /* Free the sequential zone */
319 dmz_free_zone(zmd, szone);
322 /* Free the data zone and remap the chunk */
323 dmz_invalidate_blocks(zmd, dzone, 0, dmz_zone_nr_blocks(zmd));
325 dmz_unmap_zone(zmd, dzone);
326 dmz_unlock_zone_reclaim(dzone);
327 dmz_free_zone(zmd, dzone);
328 dmz_map_zone(zmd, szone, chunk);
332 dmz_unlock_flush(zmd);
338 * Reclaim an empty zone.
340 static void dmz_reclaim_empty(struct dmz_reclaim *zrc, struct dm_zone *dzone)
342 struct dmz_metadata *zmd = zrc->metadata;
346 dmz_unmap_zone(zmd, dzone);
347 dmz_unlock_zone_reclaim(dzone);
348 dmz_free_zone(zmd, dzone);
350 dmz_unlock_flush(zmd);
354 * Test if the target device is idle.
356 static inline int dmz_target_idle(struct dmz_reclaim *zrc)
358 return time_is_before_jiffies(zrc->atime + DMZ_IDLE_PERIOD);
362 * Find a candidate zone for reclaim and process it.
364 static int dmz_do_reclaim(struct dmz_reclaim *zrc)
366 struct dmz_metadata *zmd = zrc->metadata;
367 struct dm_zone *dzone;
368 struct dm_zone *rzone;
372 /* Get a data zone */
373 dzone = dmz_get_zone_for_reclaim(zmd, zrc->dev_idx,
374 dmz_target_idle(zrc));
376 DMDEBUG("(%s/%u): No zone found to reclaim",
377 dmz_metadata_label(zmd), zrc->dev_idx);
383 if (dmz_is_cache(dzone) || dmz_is_rnd(dzone)) {
384 if (!dmz_weight(dzone)) {
386 dmz_reclaim_empty(zrc, dzone);
390 * Reclaim the random data zone by moving its
391 * valid data blocks to a free sequential zone.
393 ret = dmz_reclaim_rnd_data(zrc, dzone);
396 struct dm_zone *bzone = dzone->bzone;
397 sector_t chunk_block = 0;
399 ret = dmz_first_valid_block(zmd, bzone, &chunk_block);
403 if (ret == 0 || chunk_block >= dzone->wp_block) {
405 * The buffer zone is empty or its valid blocks are
406 * after the data zone write pointer.
408 ret = dmz_reclaim_buf(zrc, dzone);
412 * Reclaim the data zone by merging it into the
413 * buffer zone so that the buffer zone itself can
414 * be later reclaimed.
416 ret = dmz_reclaim_seq_data(zrc, dzone);
422 DMDEBUG("(%s/%u): reclaim zone %u interrupted",
423 dmz_metadata_label(zmd), zrc->dev_idx,
426 DMDEBUG("(%s/%u): Failed to reclaim zone %u, err %d",
427 dmz_metadata_label(zmd), zrc->dev_idx,
429 dmz_unlock_zone_reclaim(dzone);
433 ret = dmz_flush_metadata(zrc->metadata);
435 DMDEBUG("(%s/%u): Metadata flush for zone %u failed, err %d",
436 dmz_metadata_label(zmd), zrc->dev_idx, rzone->id, ret);
440 DMDEBUG("(%s/%u): Reclaimed zone %u in %u ms",
441 dmz_metadata_label(zmd), zrc->dev_idx,
442 rzone->id, jiffies_to_msecs(jiffies - start));
446 static unsigned int dmz_reclaim_percentage(struct dmz_reclaim *zrc)
448 struct dmz_metadata *zmd = zrc->metadata;
449 unsigned int nr_cache = dmz_nr_cache_zones(zmd);
450 unsigned int nr_unmap, nr_zones;
454 nr_unmap = dmz_nr_unmap_cache_zones(zmd);
456 nr_zones = dmz_nr_rnd_zones(zmd, zrc->dev_idx);
457 nr_unmap = dmz_nr_unmap_rnd_zones(zmd, zrc->dev_idx);
461 return nr_unmap * 100 / nr_zones;
465 * Test if reclaim is necessary.
467 static bool dmz_should_reclaim(struct dmz_reclaim *zrc, unsigned int p_unmap)
469 unsigned int nr_reclaim;
471 nr_reclaim = dmz_nr_rnd_zones(zrc->metadata, zrc->dev_idx);
473 if (dmz_nr_cache_zones(zrc->metadata)) {
475 * The first device in a multi-device
476 * setup only contains cache zones, so
477 * never start reclaim there.
479 if (zrc->dev_idx == 0)
481 nr_reclaim += dmz_nr_cache_zones(zrc->metadata);
484 /* Reclaim when idle */
485 if (dmz_target_idle(zrc) && nr_reclaim)
488 /* If there are still plenty of cache zones, do not reclaim */
489 if (p_unmap >= DMZ_RECLAIM_HIGH_UNMAP_ZONES)
493 * If the percentage of unmapped cache zones is low,
494 * reclaim even if the target is busy.
496 return p_unmap <= DMZ_RECLAIM_LOW_UNMAP_ZONES;
500 * Reclaim work function.
502 static void dmz_reclaim_work(struct work_struct *work)
504 struct dmz_reclaim *zrc = container_of(work, struct dmz_reclaim, work.work);
505 struct dmz_metadata *zmd = zrc->metadata;
506 unsigned int p_unmap;
509 if (dmz_dev_is_dying(zmd))
512 p_unmap = dmz_reclaim_percentage(zrc);
513 if (!dmz_should_reclaim(zrc, p_unmap)) {
514 mod_delayed_work(zrc->wq, &zrc->work, DMZ_IDLE_PERIOD);
519 * We need to start reclaiming random zones: set up zone copy
520 * throttling to either go fast if we are very low on random zones
521 * and slower if there are still some free random zones to avoid
522 * as much as possible to negatively impact the user workload.
524 if (dmz_target_idle(zrc) || p_unmap < DMZ_RECLAIM_LOW_UNMAP_ZONES / 2) {
525 /* Idle or very low percentage: go fast */
526 zrc->kc_throttle.throttle = 100;
528 /* Busy but we still have some random zone: throttle */
529 zrc->kc_throttle.throttle = min(75U, 100U - p_unmap / 2);
532 DMDEBUG("(%s/%u): Reclaim (%u): %s, %u%% free zones (%u/%u cache %u/%u random)",
533 dmz_metadata_label(zmd), zrc->dev_idx,
534 zrc->kc_throttle.throttle,
535 (dmz_target_idle(zrc) ? "Idle" : "Busy"),
536 p_unmap, dmz_nr_unmap_cache_zones(zmd),
537 dmz_nr_cache_zones(zmd),
538 dmz_nr_unmap_rnd_zones(zmd, zrc->dev_idx),
539 dmz_nr_rnd_zones(zmd, zrc->dev_idx));
541 ret = dmz_do_reclaim(zrc);
542 if (ret && ret != -EINTR) {
543 if (!dmz_check_dev(zmd))
547 dmz_schedule_reclaim(zrc);
551 * Initialize reclaim.
553 int dmz_ctr_reclaim(struct dmz_metadata *zmd,
554 struct dmz_reclaim **reclaim, int idx)
556 struct dmz_reclaim *zrc;
559 zrc = kzalloc(sizeof(struct dmz_reclaim), GFP_KERNEL);
564 zrc->atime = jiffies;
567 /* Reclaim kcopyd client */
568 zrc->kc = dm_kcopyd_client_create(&zrc->kc_throttle);
569 if (IS_ERR(zrc->kc)) {
570 ret = PTR_ERR(zrc->kc);
576 INIT_DELAYED_WORK(&zrc->work, dmz_reclaim_work);
577 zrc->wq = alloc_ordered_workqueue("dmz_rwq_%s_%d", WQ_MEM_RECLAIM,
578 dmz_metadata_label(zmd), idx);
585 queue_delayed_work(zrc->wq, &zrc->work, 0);
590 dm_kcopyd_client_destroy(zrc->kc);
599 void dmz_dtr_reclaim(struct dmz_reclaim *zrc)
601 cancel_delayed_work_sync(&zrc->work);
602 destroy_workqueue(zrc->wq);
603 dm_kcopyd_client_destroy(zrc->kc);
610 void dmz_suspend_reclaim(struct dmz_reclaim *zrc)
612 cancel_delayed_work_sync(&zrc->work);
618 void dmz_resume_reclaim(struct dmz_reclaim *zrc)
620 queue_delayed_work(zrc->wq, &zrc->work, DMZ_IDLE_PERIOD);
626 void dmz_reclaim_bio_acc(struct dmz_reclaim *zrc)
628 zrc->atime = jiffies;
632 * Start reclaim if necessary.
634 void dmz_schedule_reclaim(struct dmz_reclaim *zrc)
636 unsigned int p_unmap = dmz_reclaim_percentage(zrc);
638 if (dmz_should_reclaim(zrc, p_unmap))
639 mod_delayed_work(zrc->wq, &zrc->work, 0);