On Thu, Jun 13, 2024 at 05:00:32PM +0800, Zhang Yi wrote:
> From: Zhang Yi <yi.zhang@xxxxxxxxxx>
>
> If we truncate down a big realtime inode, zero out the entire aligned
> EOF extent could gets slow down as the rtextsize increases. Fortunately,
> __xfs_bunmapi() would align the unmapped range to rtextsize, split and
> convert the blocks beyond EOF to unwritten. So speed up this by
> adjusting the unitsize to the filesystem blocksize when truncating down
> a large realtime inode, let __xfs_bunmapi() convert the tail blocks to
> unwritten, this could improve the performance significantly.
>
> # mkfs.xfs -f -rrtdev=/dev/pmem1s -f -m reflink=0,rmapbt=0, \
> -d rtinherit=1 -r extsize=$rtextsize /dev/pmem2s
> # mount -ortdev=/dev/pmem1s /dev/pmem2s /mnt/scratch
> # for i in {1..1000}; \
> do dd if=/dev/zero of=/mnt/scratch/$i bs=$rtextsize count=1024; done
> # sync
> # time for i in {1..1000}; \
> do xfs_io -c "truncate 4k" /mnt/scratch/$i; done
>
> rtextsize 8k 16k 32k 64k 256k 1024k
> before: 9.601s 10.229s 11.153s 12.086s 12.259s 20.141s
> after: 9.710s 9.642s 9.958s 9.441s 10.021s 10.526s
>
> Signed-off-by: Zhang Yi <yi.zhang@xxxxxxxxxx>
> ---
> fs/xfs/xfs_inode.c | 10 ++++++++--
> fs/xfs/xfs_iops.c | 9 +++++++++
> 2 files changed, 17 insertions(+), 2 deletions(-)
>
> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> index 92daa2279053..5e837ed093b0 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -1487,6 +1487,7 @@ xfs_itruncate_extents_flags(
> struct xfs_trans *tp = *tpp;
> xfs_fileoff_t first_unmap_block;
> int error = 0;
> + unsigned int unitsize = xfs_inode_alloc_unitsize(ip);
>
> xfs_assert_ilocked(ip, XFS_ILOCK_EXCL);
> if (atomic_read(&VFS_I(ip)->i_count))
> @@ -1510,9 +1511,14 @@ xfs_itruncate_extents_flags(
> *
> * We have to free all the blocks to the bmbt maximum offset, even if
> * the page cache can't scale that far.
> + *
> + * For big realtime inode, don't aligned to allocation unitsize,
> + * it'll split the extent and convert the tail blocks to unwritten.
> */
> + if (xfs_inode_has_bigrtalloc(ip))
> + unitsize = i_blocksize(VFS_I(ip));
> + first_unmap_block = XFS_B_TO_FSB(mp, roundup_64(new_size, unitsize));
If you expand what xfs_inode_alloc_unitsize and xfs_inode_has_bigrtalloc
this is looking a bit silly:
unsigned int blocks = 1;
if (XFS_IS_REALTIME_INODE(ip))
blocks = ip->i_mount->m_sb.sb_rextsize;
unitsize = XFS_FSB_TO_B(ip->i_mount, blocks);
if (XFS_IS_REALTIME_INODE(ip) && ip->i_mount->m_sb.sb_rextsize > 1)
unsitsize = i_blocksize(inode);
So I think we can simply drop this part now that the variant that zeroes
the entire rtextent is gone.
> @@ -862,6 +862,15 @@ xfs_setattr_truncate_data(
> /* Truncate down */
> blocksize = xfs_inode_alloc_unitsize(ip);
>
> + /*
> + * If it's a big realtime inode, zero out the entire EOF extent could
> + * get slow down as the rtextsize increases, speed it up by adjusting
> + * the blocksize to the filesystem blocksize, let __xfs_bunmapi() to
> + * split the extent and convert the tail blocks to unwritten.
> + */
> + if (xfs_inode_has_bigrtalloc(ip))
> + blocksize = i_blocksize(inode);
Same here. And with that probably also the passing of the block size
to the truncate_page helpers.
