Re: [PATCH 2/2] xfs: process free extents to busy list in FIFO order

Darrick J. Wong
2023-10-10T17:34:08Z

On Mon, Oct 09, 2023 at 11:56:32PM -0700, Christoph Hellwig wrote:
> On Mon, Oct 09, 2023 at 11:25:56AM -0700, Darrick J. Wong wrote:
> > From: Darrick J. Wong <djwong@kernel.org>
> >
> > When we're adding extents to the busy discard list, add them to the tail
> > of the list so that we get FIFO order. For FITRIM commands, this means
> > that we send discard bios sorted in order from longest to shortest, like
> > we did before commit 89cfa899608fc.
> >
> > For transactions that are freeing extents, this puts them in the
> > transaction's busy list in FIFO order as well, which shouldn't make any
> > noticeable difference.
> >
> > Fixes: 89cfa899608fc ("xfs: reduce AGF hold times during fstrim operations")
> > Signed-off-by: Darrick J. Wong <djwong@kernel.org>
>
> Does this actually fix an observed issue, or just restor the previous
> behavior?

I don't /think/ there's a real issue here; it just looks funny that the
tracepoints are now ordered from higher to lower LBAs within arbitrarily
sized groups.

--D

> Eitherway the change make sense:
>
> Reviewed-by: Christoph Hellwig <hch@lst.de>