Re: [PATCH 1/1] xfs: fix severe performance problems when fstrimming a subset of an AG

Christoph Hellwig
2024-03-30T05:38:47Z

On Fri, Mar 29, 2024 at 02:35:20PM -0700, Darrick J. Wong wrote:
> Welll... you could argue that if the underlying "thin provisioning" is
> actually just an xfs file, that punching tons of tiny holes in that file
> could increase the height of the bmbt. In that case, you'd want to
> reduce the chances of the punch failing with ENOSPC by punching out
> larger ranges to free up more blocks.

That is a somewhat reaonable line of thougt. But is an underprovisioned
device near ENOSPC really the target here vs an SSD? Either way,
if we have good reasons for by-cnt except for it being a little simpler
I can live with keeping it. In doubt I just prefer to have simple code
and one implementation instead of two.