On 5/6/22 01:41, Christoph Hellwig wrote:
Hi all,
this series adds two minor improvements to iomap that allow btrfs
to avoid a memory allocation per read/write system call and another
one per submitted bio. I also have at last two other pending uses
for the iomap functionality later on, so they are not really btrfs
specific either.
Changes since v1:
- pass the private data direct to iomap_dio_rw instead of through the
iocb
- better document the bio_set in iomap_dio_ops
- split a patch into three
- use kcalloc to allocate the checksums
Diffstat:
fs/btrfs/btrfs_inode.h | 25 --------
fs/btrfs/ctree.h | 6 -
fs/btrfs/file.c | 6 -
fs/btrfs/inode.c | 152 +++++++++++++++++++++++--------------------------
fs/erofs/data.c | 2
fs/ext4/file.c | 4 -
fs/f2fs/file.c | 4 -
fs/gfs2/file.c | 4 -
fs/iomap/direct-io.c | 26 ++++++--
fs/xfs/xfs_file.c | 6 -
fs/zonefs/super.c | 4 -
include/linux/iomap.h | 16 ++++-
12 files changed, 123 insertions(+), 132 deletions(-)
This patch got me curious a couple of days back while I was tracing
a dio read performance issue on nvme. I am sharing the results as below.
[1]. There is no performance difference. Thx.
[1]
Before:
4971MB/s 4474GB iocounts: nvme3n1 545220968 nvme0n1 547007640
single_d2/5.18.0-rc5+_misc-next_1
After:
4968MB/s 4471GB iocounts: nvme3n1 544207371 nvme1n1 547458037
single_d2/5.18.0-rc5+_dio_cleanup_hch_1
readstat /btrfs fio --eta=auto --output=$CMDLOG \
--name fiotest --directory=/btrfs --rw=randread \
--bs=4k --size=4G --ioengine=libaio --iodepth=16 --direct=1 \
--time_based=1 --runtime=900 --randrepeat=1 --gtod_reduce=1 \
--group_reporting=1 --numjobs=64
