From: Naohiro Aota <naohiro.aota@xxxxxxx>
[ Upstream commit 85e79ec7b78f863178ca488fd8cb5b3de6347756 ]
The commit 79417d040f4f ("btrfs: zoned: disable metadata overcommit for
zoned") disabled the metadata over-commit to track active zones properly.
However, it also introduced a heavy overhead by allocating new metadata
block groups and/or flushing dirty buffers to release the space
reservations. Specifically, a workload (write only without any sync
operations) worsen its performance from 343.77 MB/sec (v5.19) to 182.89
MB/sec (v6.0).
The performance is still bad on current misc-next which is 187.95 MB/sec.
And, with this patch applied, it improves back to 326.70 MB/sec (+73.82%).
This patch introduces a new fs_info->flag BTRFS_FS_NO_OVERCOMMIT to
indicate it needs to disable the metadata over-commit. The flag is enabled
when a device with max active zones limit is loaded into a file-system.
Fixes: 79417d040f4f ("btrfs: zoned: disable metadata overcommit for zoned")
CC: stable@xxxxxxxxxxxxxxx # 6.0+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@xxxxxxx>
Signed-off-by: Naohiro Aota <naohiro.aota@xxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
fs/btrfs/ctree.h | 6 ++++++
fs/btrfs/space-info.c | 3 ++-
fs/btrfs/zoned.c | 2 ++
3 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 9e6d48ff4597..a3febabacec0 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -590,6 +590,12 @@ enum {
/* Indicate we have to finish a zone to do next allocation. */
BTRFS_FS_NEED_ZONE_FINISH,
+ /*
+ * Indicate metadata over-commit is disabled. This is set when active
+ * zone tracking is needed.
+ */
+ BTRFS_FS_NO_OVERCOMMIT,
+
#if BITS_PER_LONG == 32
/* Indicate if we have error/warn message printed on 32bit systems */
BTRFS_FS_32BIT_ERROR,
diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c
index f171bf875633..65c010159fb5 100644
--- a/fs/btrfs/space-info.c
+++ b/fs/btrfs/space-info.c
@@ -404,7 +404,8 @@ int btrfs_can_overcommit(struct btrfs_fs_info *fs_info,
return 0;
used = btrfs_space_info_used(space_info, true);
- if (btrfs_is_zoned(fs_info) && (space_info->flags & BTRFS_BLOCK_GROUP_METADATA))
+ if (test_bit(BTRFS_FS_NO_OVERCOMMIT, &fs_info->flags) &&
+ (space_info->flags & BTRFS_BLOCK_GROUP_METADATA))
avail = 0;
else
avail = calc_available_free_space(fs_info, space_info, flush);
diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index c9e2b0c85309..056f002263db 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -538,6 +538,8 @@ int btrfs_get_dev_zone_info(struct btrfs_device *device, bool populate_cache)
}
atomic_set(&zone_info->active_zones_left,
max_active_zones - nactive);
+ /* Overcommit does not work well with active zone tacking. */
+ set_bit(BTRFS_FS_NO_OVERCOMMIT, &fs_info->flags);
}
/* Validate superblock log */
--
2.39.0
