Re: [PATCH 1/2] xfs/078: disable all concurrency scaling

[Christoph Hellwig <hch@lst.de>]

On Fri, Jun 19, 2026 at 10:55:21AM +0900, Shin'ichiro Kawasaki wrote:
> On Jun 18, 2026 / 09:23, Eric Sandeen wrote:
> > On 6/18/26 8:54 AM, Eric Sandeen wrote:
> > > On 6/18/26 8:48 AM, Christoph Hellwig wrote:
> > >> Disable concurrency scaling to avoid mismatching output on systems with
> > >> a large CPU count.
> > >>
> > >> Reported-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
> > >> Signed-off-by: Christoph Hellwig <hch@lst.de>
> > > 
> > > I think this papers over what I still feel is a problem in mkfs.xfs
> > > behavior, but that's a different issue and making tests pass is good, so:
> > > 
> > > Reviewed-by: Eric Sandeen <sandeen@redhat.com>
> > 
> > Er, hang on - let me retract that. Lukas sent a series to address
> > this problem too, right, and one of the things he added in his series
> > is a helper to determine whether the concurrency options even exist,
> > so that this can continue to run on older xfsprogs, which seems like
> > a good idea, no?
> > 
> > https://git.kernel.org/pub/scm/fs/xfs/xfstests-dev.git/commit/?h=for-next&id=7f162f5bcf50fc32c7e3b432e7ff189571a3151f
> > 
> > which added _scratch_mkfs_xfs_supports_concurrency()
> 
> I agree, I think we can add the change below on top of this patch.
> Regardless of the change, I confirmed that this patch avoids the failure
> that I reported. Thanks!

Thanks, I'll add that.