Re: [PATCH 07/10] xfs: move stat accounting to xfs_bmapi_convert_delalloc

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Fri, Feb 15, 2019 at 03:47:22PM +0100, Christoph Hellwig wrote:
> This way we can actually count how many bytes got converted and how many
> calls we need, unlike in the caller which doesn't have the detailed
> view.
> 
> Note that this includes a slight change in behavior as the
> xs_xstrat_quick is now bumped for every allocation instead of just the
> one covering the requested writeback offset, which makes a lot more
> sense.

/me wonders if it's really supposed to be the case that we never touch
xs_xstrat_split and it stays zero, but as it hasn't done anything since
the start of linux.git I'll just set that aside for now and say...

> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Brian Foster <bfoster@redhat.com>

...this by itself seems reasonable to me.

Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> ---
>  fs/xfs/libxfs/xfs_bmap.c | 3 +++
>  fs/xfs/xfs_iomap.c       | 4 ----
>  2 files changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
> index fc4f1d3145c4..4cf83475f0d0 100644
> --- a/fs/xfs/libxfs/xfs_bmap.c
> +++ b/fs/xfs/libxfs/xfs_bmap.c
> @@ -4516,6 +4516,9 @@ xfs_bmapi_convert_delalloc(
>  	if (WARN_ON_ONCE(!bma.got.br_startblock && !XFS_IS_REALTIME_INODE(ip)))
>  		goto out_finish;
>  
> +	XFS_STATS_ADD(mp, xs_xstrat_bytes, XFS_FSB_TO_B(mp, bma.length));
> +	XFS_STATS_INC(mp, xs_xstrat_quick);
> +
>  	ASSERT(!isnullstartblock(bma.got.br_startblock));
>  	*imap = bma.got;
>  	*seq = READ_ONCE(ifp->if_seq);
> diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
> index 39be741cac5a..15da53b5fb53 100644
> --- a/fs/xfs/xfs_iomap.c
> +++ b/fs/xfs/xfs_iomap.c
> @@ -707,9 +707,6 @@ xfs_iomap_write_allocate(
>  	map_start_fsb = imap->br_startoff;
>  	map_count_fsb = imap->br_blockcount;
>  
> -	XFS_STATS_ADD(mp, xs_xstrat_bytes,
> -		      XFS_FSB_TO_B(mp, imap->br_blockcount));
> -
>  	while (true) {
>  		/*
>  		 * Allocate in a loop because it may take several attempts to
> @@ -741,7 +738,6 @@ xfs_iomap_write_allocate(
>  		if ((offset_fsb >= imap->br_startoff) &&
>  		    (offset_fsb < (imap->br_startoff +
>  				   imap->br_blockcount))) {
> -			XFS_STATS_INC(mp, xs_xstrat_quick);
>  			xfs_trim_extent(imap, map_start_fsb, map_count_fsb);
>  			ASSERT(offset_fsb >= imap->br_startoff &&
>  			       offset_fsb < imap->br_startoff + imap->br_blockcount);
> -- 
> 2.20.1
>