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	id BFF1A68BFE; Fri, 24 Jul 2026 08:33:42 +0200 (CEST)
Date: Fri, 24 Jul 2026 08:33:42 +0200
From: Christoph Hellwig <hch@lst.de>
To: "Darrick J. Wong" <djwong@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
	Christian Brauner <brauner@kernel.org>,
	Carlos Maiolino <cem@kernel.org>, Tal Zussman <tz2294@columbia.edu>,
	Anuj Gupta <anuj20.g@samsung.com>, linux-block@vger.kernel.org,
	linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 20/22] xfs: add support for lazy direct read bounce
 buffering
Message-ID: <20260724063342.GA5328@lst.de>
References: <20260723145000.116419-1-hch@lst.de> <20260723145000.116419-21-hch@lst.de> <20260723210550.GJ2901224@frogsfrogsfrogs> <20260724062443.GE4953@lst.de>
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User-Agent: Mutt/1.5.17 (2007-11-01)

On Fri, Jul 24, 2026 at 08:24:43AM +0200, Christoph Hellwig wrote:
> > > +	/* .../xfs/<dev>/csum/ */
> > > +	error = xfs_sysfs_init(&mp->m_csum_kobj, &xfs_csum_ktype,
> > > +			       &mp->m_kobj, "csum");
> > > +	if (error)
> > > +		goto out_remove_error_dir;
> > 
> > /me wonders if this is a debugging knob and therefore should go in
> > debugfs?  Or is there a solid usecase for normal sysadmins to be able to
> > control this?
> 
> I consider it an insurance again mispredicting user workloads.  debugfs
> also is really painful in general, and especially for trivial files
> likes this where it requires tons of boilerplate for no reason.

Also: I'm not particular happy about the placement of this file
in sysfs.  Do we want a misc group, or rw?  The current one feels
a bit too specific, which means we'd keep on growing way too many
groups in the future.