Commit 3687fcb0 authored by Johannes Thumshirn's avatar Johannes Thumshirn Committed by David Sterba
Browse files

btrfs: zoned: make auto-reclaim less aggressive 



The current auto-reclaim algorithm starts reclaiming all block groups
with a zone_unusable value above a configured threshold. This is causing
a lot of reclaim IO even if there would be enough free zones on the
device.

Instead of only accounting a block groups zone_unusable value, also take
the ratio of free and not usable (written as well as zone_unusable)
bytes a device has into account.

Tested-by: default avatarPankaj Raghav <p.raghav@samsung.com>
Signed-off-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent ef972e7b

fs/btrfs/block-group.c

+10 −0
Original line number Diff line number Diff line
@@ -1512,6 +1512,13 @@ static int reclaim_bgs_cmp(void *unused, const struct list_head *a, 
	return bg1->used > bg2->used;

}



static inline bool btrfs_should_reclaim(struct btrfs_fs_info *fs_info)

{

	if (btrfs_is_zoned(fs_info))

		return btrfs_zoned_should_reclaim(fs_info);

	return true;

}



void btrfs_reclaim_bgs_work(struct work_struct *work)

{

	struct btrfs_fs_info *fs_info =
@@ -1522,6 +1529,9 @@ void btrfs_reclaim_bgs_work(struct work_struct *work) 
	if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))

		return;



	if (!btrfs_should_reclaim(fs_info))

		return;



	sb_start_write(fs_info->sb);



	if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_BALANCE)) {

fs/btrfs/zoned.c

+27 −0
Original line number Diff line number Diff line
@@ -2073,3 +2073,30 @@ void btrfs_free_zone_cache(struct btrfs_fs_info *fs_info) 
	}

	mutex_unlock(&fs_devices->device_list_mutex);

}



bool btrfs_zoned_should_reclaim(struct btrfs_fs_info *fs_info)

{

	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;

	struct btrfs_device *device;

	u64 used = 0;

	u64 total = 0;

	u64 factor;



	ASSERT(btrfs_is_zoned(fs_info));



	if (fs_info->bg_reclaim_threshold == 0)

		return false;



	mutex_lock(&fs_devices->device_list_mutex);

	list_for_each_entry(device, &fs_devices->devices, dev_list) {

		if (!device->bdev)

			continue;



		total += device->disk_total_bytes;

		used += device->bytes_used;

	}

	mutex_unlock(&fs_devices->device_list_mutex);



	factor = div64_u64(used * 100, total);

	return factor >= fs_info->bg_reclaim_threshold;

}

fs/btrfs/zoned.h

+6 −0
Original line number Diff line number Diff line
@@ -74,6 +74,7 @@ void btrfs_zone_finish_endio(struct btrfs_fs_info *fs_info, u64 logical, 
			     u64 length);

void btrfs_clear_data_reloc_bg(struct btrfs_block_group *bg);

void btrfs_free_zone_cache(struct btrfs_fs_info *fs_info);

bool btrfs_zoned_should_reclaim(struct btrfs_fs_info *fs_info);

#else /* CONFIG_BLK_DEV_ZONED */

static inline int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,

				     struct blk_zone *zone)
@@ -232,6 +233,11 @@ static inline void btrfs_zone_finish_endio(struct btrfs_fs_info *fs_info, 
static inline void btrfs_clear_data_reloc_bg(struct btrfs_block_group *bg) { }



static inline void btrfs_free_zone_cache(struct btrfs_fs_info *fs_info) { }



static inline bool btrfs_zoned_should_reclaim(struct btrfs_fs_info *fs_info)

{

	return false;

}

#endif



static inline bool btrfs_dev_is_sequential(struct btrfs_device *device, u64 pos)