diff mbox series

[v2,1/6] btrfs: report reclaim stats in sysfs

Message ID 65bfe2e6aae82f4d58f6592dcdbb827e20982a3f.1718665689.git.boris@bur.io (mailing list archive)
State New, archived
Headers show
Series btrfs: dynamic and periodic block_group reclaim | expand

Commit Message

Boris Burkov June 17, 2024, 11:11 p.m. UTC 
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: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Boris Burkov <boris@bur.io>
---
 fs/btrfs/block-group.c | 10 ++++++++++
 fs/btrfs/space-info.h  | 18 ++++++++++++++++++
 fs/btrfs/sysfs.c       |  6 ++++++
 3 files changed, 34 insertions(+)
diff mbox series

Patch

diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index 9f1d328b603e..824fd229d129 100644
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -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) {
diff --git a/fs/btrfs/space-info.h b/fs/btrfs/space-info.h
index a733458fd13b..98ea35ae60fe 100644
--- a/fs/btrfs/space-info.h
+++ b/fs/btrfs/space-info.h
@@ -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 {
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index af545b6b1190..919c7ba45121 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -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