Commit 243192b6 authored by Boris Burkov's avatar Boris Burkov Committed by David Sterba
Browse files

btrfs: report reclaim stats in sysfs 



When evaluating various reclaim strategies/thresholds against each
other, it is useful to collect data about the amount of reclaim
happening. Expose a count, error count, and byte count via sysfs
per space_info.

Note that this is only for automatic reclaim, not manually invoked
balances or other codepaths that use "relocate_block_group"

Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Reviewed-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: default avatarBoris Burkov <boris@bur.io>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent a5b3abb1

fs/btrfs/block-group.c

+10 −0
Original line number Diff line number Diff line
@@ -1829,6 +1829,7 @@ void btrfs_reclaim_bgs_work(struct work_struct *work) 
	list_sort(NULL, &fs_info->reclaim_bgs, reclaim_bgs_cmp);

	while (!list_empty(&fs_info->reclaim_bgs)) {

		u64 zone_unusable;

		u64 reclaimed;

		int ret = 0;



		bg = list_first_entry(&fs_info->reclaim_bgs,
@@ -1921,12 +1922,21 @@ void btrfs_reclaim_bgs_work(struct work_struct *work) 
				div64_u64(bg->used * 100, bg->length),

				div64_u64(zone_unusable * 100, bg->length));

		trace_btrfs_reclaim_block_group(bg);

		reclaimed = bg->used;

		ret = btrfs_relocate_chunk(fs_info, bg->start);

		if (ret) {

			btrfs_dec_block_group_ro(bg);

			btrfs_err(fs_info, "error relocating chunk %llu",

				  bg->start);

			reclaimed = 0;

			spin_lock(&space_info->lock);

			space_info->reclaim_errors++;

			spin_unlock(&space_info->lock);

		}

		spin_lock(&space_info->lock);

		space_info->reclaim_count++;

		space_info->reclaim_bytes += reclaimed;

		spin_unlock(&space_info->lock);



next:

		if (ret) {

fs/btrfs/space-info.h

+18 −0
Original line number Diff line number Diff line
@@ -165,6 +165,24 @@ struct btrfs_space_info { 


	struct kobject kobj;

	struct kobject *block_group_kobjs[BTRFS_NR_RAID_TYPES];



	/*

	 * Monotonically increasing counter of block group reclaim attempts

	 * Exposed in /sys/fs/<uuid>/allocation/<type>/reclaim_count

	 */

	u64 reclaim_count;



	/*

	 * Monotonically increasing counter of reclaimed bytes

	 * Exposed in /sys/fs/<uuid>/allocation/<type>/reclaim_bytes

	 */

	u64 reclaim_bytes;



	/*

	 * Monotonically increasing counter of reclaim errors

	 * Exposed in /sys/fs/<uuid>/allocation/<type>/reclaim_errors

	 */

	u64 reclaim_errors;

};



struct reserve_ticket {

fs/btrfs/sysfs.c

+6 −0
Original line number Diff line number Diff line
@@ -894,6 +894,9 @@ SPACE_INFO_ATTR(bytes_readonly); 
SPACE_INFO_ATTR(bytes_zone_unusable);

SPACE_INFO_ATTR(disk_used);

SPACE_INFO_ATTR(disk_total);

SPACE_INFO_ATTR(reclaim_count);

SPACE_INFO_ATTR(reclaim_bytes);

SPACE_INFO_ATTR(reclaim_errors);

BTRFS_ATTR_RW(space_info, chunk_size, btrfs_chunk_size_show, btrfs_chunk_size_store);

BTRFS_ATTR(space_info, size_classes, btrfs_size_classes_show);
@@ -949,6 +952,9 @@ static struct attribute *space_info_attrs[] = { 
	BTRFS_ATTR_PTR(space_info, bg_reclaim_threshold),

	BTRFS_ATTR_PTR(space_info, chunk_size),

	BTRFS_ATTR_PTR(space_info, size_classes),

	BTRFS_ATTR_PTR(space_info, reclaim_count),

	BTRFS_ATTR_PTR(space_info, reclaim_bytes),

	BTRFS_ATTR_PTR(space_info, reclaim_errors),

#ifdef CONFIG_BTRFS_DEBUG

	BTRFS_ATTR_PTR(space_info, force_chunk_alloc),

#endif