// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (C) 2017 Western Digital Corporation or its affiliates. * * This file is released under the GPL. */ #include "dm-zoned.h" #include <linux/module.h> #define DM_MSG_PREFIX "zoned reclaim" struct dmz_reclaim { struct dmz_metadata *metadata; struct delayed_work work; struct workqueue_struct *wq; struct dm_kcopyd_client *kc; struct dm_kcopyd_throttle kc_throttle; int kc_err; int dev_idx; unsigned long flags; /* Last target access time */ unsigned long atime; }; /* * Reclaim state flags. */ enum { DMZ_RECLAIM_KCOPY, }; /* * Number of seconds of target BIO inactivity to consider the target idle. */ #define DMZ_IDLE_PERIOD (10UL * HZ) /* * Percentage of unmapped (free) random zones below which reclaim starts * even if the target is busy. */ #define DMZ_RECLAIM_LOW_UNMAP_ZONES 30 /* * Percentage of unmapped (free) random zones above which reclaim will * stop if the target is busy. */ #define DMZ_RECLAIM_HIGH_UNMAP_ZONES 50 /* * Align a sequential zone write pointer to chunk_block. */ static int dmz_reclaim_align_wp(struct dmz_reclaim *zrc, struct dm_zone *zone, sector_t block) { struct dmz_metadata *zmd = zrc->metadata; struct dmz_dev *dev = zone->dev; sector_t wp_block = zone->wp_block; unsigned int nr_blocks; int ret; if (wp_block == block) return 0; if (wp_block > block) return -EIO; /* * Zeroout the space between the write * pointer and the requested position. */ nr_blocks = block - wp_block; ret = blkdev_issue_zeroout(dev->bdev, dmz_start_sect(zmd, zone) + dmz_blk2sect(wp_block), dmz_blk2sect(nr_blocks), GFP_NOIO, 0); if (ret) { dmz_dev_err(dev, "Align zone %u wp %llu to %llu (wp+%u) blocks failed %d", zone->id, (unsigned long long)wp_block, (unsigned long long)block, nr_blocks, ret); dmz_check_bdev(dev); return ret; } zone->wp_block = block; return 0; } /* * dm_kcopyd_copy end notification. */ static void dmz_reclaim_kcopy_end(int read_err, unsigned long write_err, void *context) { struct dmz_reclaim *zrc = context; if (read_err || write_err) zrc->kc_err = -EIO; else zrc->kc_err = 0; clear_bit_unlock(DMZ_RECLAIM_KCOPY, &zrc->flags); smp_mb__after_atomic(); wake_up_bit(&zrc->flags, DMZ_RECLAIM_KCOPY); } /* * Copy valid blocks of src_zone into dst_zone. */ static int dmz_reclaim_copy(struct dmz_reclaim *zrc, struct dm_zone *src_zone, struct dm_zone *dst_zone) { struct dmz_metadata *zmd = zrc->metadata; struct dm_io_region src, dst; sector_t block = 0, end_block; sector_t nr_blocks; sector_t src_zone_block; sector_t dst_zone_block; unsigned long flags = 0; int ret; if (dmz_is_seq(src_zone)) end_block = src_zone->wp_block; else end_block = dmz_zone_nr_blocks(zmd); src_zone_block = dmz_start_block(zmd, src_zone); dst_zone_block = dmz_start_block(zmd, dst_zone); if (dmz_is_seq(dst_zone)) flags |= BIT(DM_KCOPYD_WRITE_SEQ); while (block < end_block) { if (src_zone->dev->flags & DMZ_BDEV_DYING) return -EIO; if (dst_zone->dev->flags & DMZ_BDEV_DYING) return -EIO; if (dmz_reclaim_should_terminate(src_zone)) return -EINTR; /* Get a valid region from the source zone */ ret = dmz_first_valid_block(zmd, src_zone, &block); if (ret <= 0) return ret; nr_blocks = ret; /* * If we are writing in a sequential zone, we must make sure * that writes are sequential. So Zeroout any eventual hole * between writes. */ if (dmz_is_seq(dst_zone)) { ret = dmz_reclaim_align_wp(zrc, dst_zone, block); if (ret) return ret; } src.bdev = src_zone->dev->bdev; src.sector = dmz_blk2sect(src_zone_block + block); src.count = dmz_blk2sect(nr_blocks); dst.bdev = dst_zone->dev->bdev; dst.sector = dmz_blk2sect(dst_zone_block + block); dst.count = src.count; /* Copy the valid region */ set_bit(DMZ_RECLAIM_KCOPY, &zrc->flags); dm_kcopyd_copy(zrc->kc, &src, 1, &dst, flags, dmz_reclaim_kcopy_end, zrc); /* Wait for copy to complete */ wait_on_bit_io(&zrc->flags, DMZ_RECLAIM_KCOPY, TASK_UNINTERRUPTIBLE); if (zrc->kc_err) return zrc->kc_err; block += nr_blocks; if (dmz_is_seq(dst_zone)) dst_zone->wp_block = block; } return 0; } /* * Move valid blocks of dzone buffer zone into dzone (after its write pointer) * and free the buffer zone. */ static int dmz_reclaim_buf(struct dmz_reclaim *zrc, struct dm_zone *dzone) { struct dm_zone *bzone = dzone->bzone; sector_t chunk_block = dzone->wp_block; struct dmz_metadata *zmd = zrc->metadata; int ret; DMDEBUG("(%s/%u): Chunk %u, move buf zone %u (weight %u) to data zone %u (weight %u)", dmz_metadata_label(zmd), zrc->dev_idx, dzone->chunk, bzone->id, dmz_weight(bzone), dzone->id, dmz_weight(dzone)); /* Flush data zone into the buffer zone */ ret = dmz_reclaim_copy(zrc, bzone, dzone); if (ret < 0) return ret; dmz_lock_flush(zmd); /* Validate copied blocks */ ret = dmz_merge_valid_blocks(zmd, bzone, dzone, chunk_block); if (ret == 0) { /* Free the buffer zone */ dmz_invalidate_blocks(zmd, bzone, 0, dmz_zone_nr_blocks(zmd)); dmz_lock_map(zmd); dmz_unmap_zone(zmd, bzone); dmz_unlock_zone_reclaim(dzone); dmz_free_zone(zmd, bzone); dmz_unlock_map(zmd); } dmz_unlock_flush(zmd); return ret; } /* * Merge valid blocks of dzone into its buffer zone and free dzone. */ static int dmz_reclaim_seq_data(struct dmz_reclaim *zrc, struct dm_zone *dzone) { unsigned int chunk = dzone->chunk; struct dm_zone *bzone = dzone->bzone; struct dmz_metadata *zmd = zrc->metadata; int ret = 0; DMDEBUG("(%s/%u): Chunk %u, move data zone %u (weight %u) to buf zone %u (weight %u)", dmz_metadata_label(zmd), zrc->dev_idx, chunk, dzone->id, dmz_weight(dzone), bzone->id, dmz_weight(bzone)); /* Flush data zone into the buffer zone */ ret = dmz_reclaim_copy(zrc, dzone, bzone); if (ret < 0) return ret; dmz_lock_flush(zmd); /* Validate copied blocks */ ret = dmz_merge_valid_blocks(zmd, dzone, bzone, 0); if (ret == 0) { /* * Free the data zone and remap the chunk to * the buffer zone. */ dmz_invalidate_blocks(zmd, dzone, 0, dmz_zone_nr_blocks(zmd)); dmz_lock_map(zmd); dmz_unmap_zone(zmd, bzone); dmz_unmap_zone(zmd, dzone); dmz_unlock_zone_reclaim(dzone); dmz_free_zone(zmd, dzone); dmz_map_zone(zmd, bzone, chunk); dmz_unlock_map(zmd); } dmz_unlock_flush(zmd); return ret; } /* * Move valid blocks of the random data zone dzone into a free sequential zone. * Once blocks are moved, remap the zone chunk to the sequential zone. */ static int dmz_reclaim_rnd_data(struct dmz_reclaim *zrc, struct dm_zone *dzone) { unsigned int chunk = dzone->chunk; struct dm_zone *szone = NULL; struct dmz_metadata *zmd = zrc->metadata; int ret; int alloc_flags = DMZ_ALLOC_SEQ; /* Get a free random or sequential zone */ dmz_lock_map(zmd); again: szone = dmz_alloc_zone(zmd, zrc->dev_idx, alloc_flags | DMZ_ALLOC_RECLAIM); if (!szone && alloc_flags == DMZ_ALLOC_SEQ && dmz_nr_cache_zones(zmd)) { alloc_flags = DMZ_ALLOC_RND; goto again; } dmz_unlock_map(zmd); if (!szone) return -ENOSPC; DMDEBUG("(%s/%u): Chunk %u, move %s zone %u (weight %u) to %s zone %u", dmz_metadata_label(zmd), zrc->dev_idx, chunk, dmz_is_cache(dzone) ? "cache" : "rnd", dzone->id, dmz_weight(dzone), dmz_is_rnd(szone) ? "rnd" : "seq", szone->id); /* Flush the random data zone into the sequential zone */ ret = dmz_reclaim_copy(zrc, dzone, szone); dmz_lock_flush(zmd); if (ret == 0) { /* Validate copied blocks */ ret = dmz_copy_valid_blocks(zmd, dzone, szone); } if (ret) { /* Free the sequential zone */ dmz_lock_map(zmd); dmz_free_zone(zmd, szone); dmz_unlock_map(zmd); } else { /* Free the data zone and remap the chunk */ dmz_invalidate_blocks(zmd, dzone, 0, dmz_zone_nr_blocks(zmd)); dmz_lock_map(zmd); dmz_unmap_zone(zmd, dzone); dmz_unlock_zone_reclaim(dzone); dmz_free_zone(zmd, dzone); dmz_map_zone(zmd, szone, chunk); dmz_unlock_map(zmd); } dmz_unlock_flush(zmd); return ret; } /* * Reclaim an empty zone. */ static void dmz_reclaim_empty(struct dmz_reclaim *zrc, struct dm_zone *dzone) { struct dmz_metadata *zmd = zrc->metadata; dmz_lock_flush(zmd); dmz_lock_map(zmd); dmz_unmap_zone(zmd, dzone); dmz_unlock_zone_reclaim(dzone); dmz_free_zone(zmd, dzone); dmz_unlock_map(zmd); dmz_unlock_flush(zmd); } /* * Test if the target device is idle. */ static inline int dmz_target_idle(struct dmz_reclaim *zrc) { return time_is_before_jiffies(zrc->atime + DMZ_IDLE_PERIOD); } /* * Find a candidate zone for reclaim and process it. */ static int dmz_do_reclaim(struct dmz_reclaim *zrc) { struct dmz_metadata *zmd = zrc->metadata; struct dm_zone *dzone; struct dm_zone *rzone; unsigned long start; int ret; /* Get a data zone */ dzone = dmz_get_zone_for_reclaim(zmd, zrc->dev_idx, dmz_target_idle(zrc)); if (!dzone) { DMDEBUG("(%s/%u): No zone found to reclaim", dmz_metadata_label(zmd), zrc->dev_idx); return -EBUSY; } rzone = dzone; start = jiffies; if (dmz_is_cache(dzone) || dmz_is_rnd(dzone)) { if (!dmz_weight(dzone)) { /* Empty zone */ dmz_reclaim_empty(zrc, dzone); ret = 0; } else { /* * Reclaim the random data zone by moving its * valid data blocks to a free sequential zone. */ ret = dmz_reclaim_rnd_data(zrc, dzone); } } else { struct dm_zone *bzone = dzone->bzone; sector_t chunk_block = 0; ret = dmz_first_valid_block(zmd, bzone, &chunk_block); if (ret < 0) goto out; if (ret == 0 || chunk_block >= dzone->wp_block) { /* * The buffer zone is empty or its valid blocks are * after the data zone write pointer. */ ret = dmz_reclaim_buf(zrc, dzone); rzone = bzone; } else { /* * Reclaim the data zone by merging it into the * buffer zone so that the buffer zone itself can * be later reclaimed. */ ret = dmz_reclaim_seq_data(zrc, dzone); } } out: if (ret) { if (ret == -EINTR) DMDEBUG("(%s/%u): reclaim zone %u interrupted", dmz_metadata_label(zmd), zrc->dev_idx, rzone->id); else DMDEBUG("(%s/%u): Failed to reclaim zone %u, err %d", dmz_metadata_label(zmd), zrc->dev_idx, rzone->id, ret); dmz_unlock_zone_reclaim(dzone); return ret; } ret = dmz_flush_metadata(zrc->metadata); if (ret) { DMDEBUG("(%s/%u): Metadata flush for zone %u failed, err %d", dmz_metadata_label(zmd), zrc->dev_idx, rzone->id, ret); return ret; } DMDEBUG("(%s/%u): Reclaimed zone %u in %u ms", dmz_metadata_label(zmd), zrc->dev_idx, rzone->id, jiffies_to_msecs(jiffies - start)); return 0; } static unsigned int dmz_reclaim_percentage(struct dmz_reclaim *zrc) { struct dmz_metadata *zmd = zrc->metadata; unsigned int nr_cache = dmz_nr_cache_zones(zmd); unsigned int nr_unmap, nr_zones; if (nr_cache) { nr_zones = nr_cache; nr_unmap = dmz_nr_unmap_cache_zones(zmd); } else { nr_zones = dmz_nr_rnd_zones(zmd, zrc->dev_idx); nr_unmap = dmz_nr_unmap_rnd_zones(zmd, zrc->dev_idx); } if (nr_unmap <= 1) return 0; return nr_unmap * 100 / nr_zones; } /* * Test if reclaim is necessary. */ static bool dmz_should_reclaim(struct dmz_reclaim *zrc, unsigned int p_unmap) { unsigned int nr_reclaim; nr_reclaim = dmz_nr_rnd_zones(zrc->metadata, zrc->dev_idx); if (dmz_nr_cache_zones(zrc->metadata)) { /* * The first device in a multi-device * setup only contains cache zones, so * never start reclaim there. */ if (zrc->dev_idx == 0) return false; nr_reclaim += dmz_nr_cache_zones(zrc->metadata); } /* Reclaim when idle */ if (dmz_target_idle(zrc) && nr_reclaim) return true; /* If there are still plenty of cache zones, do not reclaim */ if (p_unmap >= DMZ_RECLAIM_HIGH_UNMAP_ZONES) return false; /* * If the percentage of unmapped cache zones is low, * reclaim even if the target is busy. */ return p_unmap <= DMZ_RECLAIM_LOW_UNMAP_ZONES; } /* * Reclaim work function. */ static void dmz_reclaim_work(struct work_struct *work) { struct dmz_reclaim *zrc = container_of(work, struct dmz_reclaim, work.work); struct dmz_metadata *zmd = zrc->metadata; unsigned int p_unmap; int ret; if (dmz_dev_is_dying(zmd)) return; p_unmap = dmz_reclaim_percentage(zrc); if (!dmz_should_reclaim(zrc, p_unmap)) { mod_delayed_work(zrc->wq, &zrc->work, DMZ_IDLE_PERIOD); return; } /* * We need to start reclaiming random zones: set up zone copy * throttling to either go fast if we are very low on random zones * and slower if there are still some free random zones to avoid * as much as possible to negatively impact the user workload. */ if (dmz_target_idle(zrc) || p_unmap < DMZ_RECLAIM_LOW_UNMAP_ZONES / 2) { /* Idle or very low percentage: go fast */ zrc->kc_throttle.throttle = 100; } else { /* Busy but we still have some random zone: throttle */ zrc->kc_throttle.throttle = min(75U, 100U - p_unmap / 2); } DMDEBUG("(%s/%u): Reclaim (%u): %s, %u%% free zones (%u/%u cache %u/%u random)", dmz_metadata_label(zmd), zrc->dev_idx, zrc->kc_throttle.throttle, (dmz_target_idle(zrc) ? "Idle" : "Busy"), p_unmap, dmz_nr_unmap_cache_zones(zmd), dmz_nr_cache_zones(zmd), dmz_nr_unmap_rnd_zones(zmd, zrc->dev_idx), dmz_nr_rnd_zones(zmd, zrc->dev_idx)); ret = dmz_do_reclaim(zrc); if (ret && ret != -EINTR) { if (!dmz_check_dev(zmd)) return; } dmz_schedule_reclaim(zrc); } /* * Initialize reclaim. */ int dmz_ctr_reclaim(struct dmz_metadata *zmd, struct dmz_reclaim **reclaim, int idx) { struct dmz_reclaim *zrc; int ret; zrc = kzalloc(sizeof(struct dmz_reclaim), GFP_KERNEL); if (!zrc) return -ENOMEM; zrc->metadata = zmd; zrc->atime = jiffies; zrc->dev_idx = idx; /* Reclaim kcopyd client */ zrc->kc = dm_kcopyd_client_create(&zrc->kc_throttle); if (IS_ERR(zrc->kc)) { ret = PTR_ERR(zrc->kc); zrc->kc = NULL; goto err; } /* Reclaim work */ INIT_DELAYED_WORK(&zrc->work, dmz_reclaim_work); zrc->wq = alloc_ordered_workqueue("dmz_rwq_%s_%d", WQ_MEM_RECLAIM, dmz_metadata_label(zmd), idx); if (!zrc->wq) { ret = -ENOMEM; goto err; } *reclaim = zrc; queue_delayed_work(zrc->wq, &zrc->work, 0); return 0; err: if (zrc->kc) dm_kcopyd_client_destroy(zrc->kc); kfree(zrc); return ret; } /* * Terminate reclaim. */ void dmz_dtr_reclaim(struct dmz_reclaim *zrc) { cancel_delayed_work_sync(&zrc->work); destroy_workqueue(zrc->wq); dm_kcopyd_client_destroy(zrc->kc); kfree(zrc); } /* * Suspend reclaim. */ void dmz_suspend_reclaim(struct dmz_reclaim *zrc) { cancel_delayed_work_sync(&zrc->work); } /* * Resume reclaim. */ void dmz_resume_reclaim(struct dmz_reclaim *zrc) { queue_delayed_work(zrc->wq, &zrc->work, DMZ_IDLE_PERIOD); } /* * BIO accounting. */ void dmz_reclaim_bio_acc(struct dmz_reclaim *zrc) { zrc->atime = jiffies; } /* * Start reclaim if necessary. */ void dmz_schedule_reclaim(struct dmz_reclaim *zrc) { unsigned int p_unmap = dmz_reclaim_percentage(zrc); if (dmz_should_reclaim(zrc, p_unmap)) mod_delayed_work(zrc->wq, &zrc->work, 0); }