On Thu, Feb 17, 2022 at 01:50:56PM +0900, Naohiro Aota wrote:
commit 16beac87e95e2fb278b552397c8260637f8a63f7 upstream.
When mounting a device, we are reporting the zones twice: once for checking the zone attributes in btrfs_get_dev_zone_info and once for loading block groups' zone info in btrfs_load_block_group_zone_info(). With a lot of block groups, that leads to a lot of REPORT ZONE commands and slows down the mount process.
This patch introduces a zone info cache in struct btrfs_zoned_device_info. The cache is populated while in btrfs_get_dev_zone_info() and used for btrfs_load_block_group_zone_info() to reduce the number of REPORT ZONE commands. The zone cache is then released after loading the block groups, as it will not be much effective during the run time.
Benchmark: Mount an HDD with 57,007 block groups Before patch: 171.368 seconds After patch: 64.064 seconds
While it still takes a minute due to the slowness of loading all the block groups, the patch reduces the mount time by 1/3.
Link: https://lore.kernel.org/linux-btrfs/CAHQ7scUiLtcTqZOMMY5kbWUBOhGRwKo6J6wYPT5... Fixes: 5b316468983d ("btrfs: get zone information of zoned block devices") CC: stable@vger.kernel.org Signed-off-by: Naohiro Aota naohiro.aota@wdc.com Signed-off-by: David Sterba dsterba@suse.com
fs/btrfs/dev-replace.c | 2 +- fs/btrfs/disk-io.c | 2 + fs/btrfs/volumes.c | 2 +- fs/btrfs/zoned.c | 85 ++++++++++++++++++++++++++++++++++++++---- fs/btrfs/zoned.h | 8 +++- 5 files changed, 87 insertions(+), 12 deletions(-)
Now queued up, thanks.
greg k-h