diff options
Diffstat (limited to 'drivers/md/dm-zoned-reclaim.c')
| -rw-r--r-- | drivers/md/dm-zoned-reclaim.c | 588 |
1 files changed, 588 insertions, 0 deletions
diff --git a/drivers/md/dm-zoned-reclaim.c b/drivers/md/dm-zoned-reclaim.c new file mode 100644 index 000000000..879848aad --- /dev/null +++ b/drivers/md/dm-zoned-reclaim.c @@ -0,0 +1,588 @@ +/* + * 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 dmz_dev *dev; + + struct delayed_work work; + struct workqueue_struct *wq; + + struct dm_kcopyd_client *kc; + struct dm_kcopyd_throttle kc_throttle; + int kc_err; + + 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_RND 30 + +/* + * Percentage of unmapped (free) random zones above which reclaim will + * stop if the target is busy. + */ +#define DMZ_RECLAIM_HIGH_UNMAP_RND 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; + 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(zrc->dev->bdev, + dmz_start_sect(zmd, zone) + dmz_blk2sect(wp_block), + dmz_blk2sect(nr_blocks), GFP_NOIO, 0); + if (ret) { + dmz_dev_err(zrc->dev, + "Align zone %u wp %llu to %llu (wp+%u) blocks failed %d", + dmz_id(zmd, zone), (unsigned long long)wp_block, + (unsigned long long)block, nr_blocks, ret); + dmz_check_bdev(zrc->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 dmz_dev *dev = zrc->dev; + 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 = dev->zone_nr_blocks; + src_zone_block = dmz_start_block(zmd, src_zone); + dst_zone_block = dmz_start_block(zmd, dst_zone); + + if (dmz_is_seq(dst_zone)) + set_bit(DM_KCOPYD_WRITE_SEQ, &flags); + + while (block < end_block) { + if (dev->flags & DMZ_BDEV_DYING) + return -EIO; + + /* 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 = dev->bdev; + src.sector = dmz_blk2sect(src_zone_block + block); + src.count = dmz_blk2sect(nr_blocks); + + dst.bdev = 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; + + dmz_dev_debug(zrc->dev, + "Chunk %u, move buf zone %u (weight %u) to data zone %u (weight %u)", + dzone->chunk, dmz_id(zmd, bzone), dmz_weight(bzone), + dmz_id(zmd, dzone), 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, zrc->dev->zone_nr_blocks); + 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; + + dmz_dev_debug(zrc->dev, + "Chunk %u, move data zone %u (weight %u) to buf zone %u (weight %u)", + chunk, dmz_id(zmd, dzone), dmz_weight(dzone), + dmz_id(zmd, bzone), 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, zrc->dev->zone_nr_blocks); + 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; + + /* Get a free sequential zone */ + dmz_lock_map(zmd); + szone = dmz_alloc_zone(zmd, DMZ_ALLOC_RECLAIM); + dmz_unlock_map(zmd); + if (!szone) + return -ENOSPC; + + dmz_dev_debug(zrc->dev, + "Chunk %u, move rnd zone %u (weight %u) to seq zone %u", + chunk, dmz_id(zmd, dzone), dmz_weight(dzone), + dmz_id(zmd, szone)); + + /* 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, zrc->dev->zone_nr_blocks); + 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); +} + +/* + * 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); + if (!dzone) + return -EBUSY; + + start = jiffies; + + if (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); + } + rzone = 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); + rzone = dzone; + } + } +out: + if (ret) { + dmz_unlock_zone_reclaim(dzone); + return ret; + } + + ret = dmz_flush_metadata(zrc->metadata); + if (ret) { + dmz_dev_debug(zrc->dev, + "Metadata flush for zone %u failed, err %d\n", + dmz_id(zmd, rzone), ret); + return ret; + } + + dmz_dev_debug(zrc->dev, "Reclaimed zone %u in %u ms", + dmz_id(zmd, rzone), jiffies_to_msecs(jiffies - start)); + return 0; +} + +/* + * 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); +} + +/* + * Test if reclaim is necessary. + */ +static bool dmz_should_reclaim(struct dmz_reclaim *zrc) +{ + struct dmz_metadata *zmd = zrc->metadata; + unsigned int nr_rnd = dmz_nr_rnd_zones(zmd); + unsigned int nr_unmap_rnd = dmz_nr_unmap_rnd_zones(zmd); + unsigned int p_unmap_rnd = nr_unmap_rnd * 100 / nr_rnd; + + /* Reclaim when idle */ + if (dmz_target_idle(zrc) && nr_unmap_rnd < nr_rnd) + return true; + + /* If there are still plenty of random zones, do not reclaim */ + if (p_unmap_rnd >= DMZ_RECLAIM_HIGH_UNMAP_RND) + return false; + + /* + * If the percentage of unmappped random zones is low, + * reclaim even if the target is busy. + */ + return p_unmap_rnd <= DMZ_RECLAIM_LOW_UNMAP_RND; +} + +/* + * 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 nr_rnd, nr_unmap_rnd; + unsigned int p_unmap_rnd; + int ret; + + if (dmz_bdev_is_dying(zrc->dev)) + return; + + if (!dmz_should_reclaim(zrc)) { + 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. + */ + nr_rnd = dmz_nr_rnd_zones(zmd); + nr_unmap_rnd = dmz_nr_unmap_rnd_zones(zmd); + p_unmap_rnd = nr_unmap_rnd * 100 / nr_rnd; + if (dmz_target_idle(zrc) || p_unmap_rnd < DMZ_RECLAIM_LOW_UNMAP_RND / 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_rnd / 2); + } + + dmz_dev_debug(zrc->dev, + "Reclaim (%u): %s, %u%% free rnd zones (%u/%u)", + zrc->kc_throttle.throttle, + (dmz_target_idle(zrc) ? "Idle" : "Busy"), + p_unmap_rnd, nr_unmap_rnd, nr_rnd); + + ret = dmz_do_reclaim(zrc); + if (ret) { + dmz_dev_debug(zrc->dev, "Reclaim error %d\n", ret); + if (!dmz_check_bdev(zrc->dev)) + return; + } + + dmz_schedule_reclaim(zrc); +} + +/* + * Initialize reclaim. + */ +int dmz_ctr_reclaim(struct dmz_dev *dev, struct dmz_metadata *zmd, + struct dmz_reclaim **reclaim) +{ + struct dmz_reclaim *zrc; + int ret; + + zrc = kzalloc(sizeof(struct dmz_reclaim), GFP_KERNEL); + if (!zrc) + return -ENOMEM; + + zrc->dev = dev; + zrc->metadata = zmd; + zrc->atime = jiffies; + + /* 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", WQ_MEM_RECLAIM, + dev->name); + 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) +{ + if (dmz_should_reclaim(zrc)) + mod_delayed_work(zrc->wq, &zrc->work, 0); +} + |