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Date: Wed, 10 Jan 2024 17:18:29 +0100
From: Christoph Hellwig <hch@lst.de>
To: Matthew Wilcox <willy@infradead.org>
Subject: Re: disable large folios for shmem file used by xfs xfile
Message-ID: <20240110161829.GA1105@lst.de>
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Cc: "Darrick J . Wong" <djwong@kernel.org>, dri-devel@lists.freedesktop.org,
 David Howells <dhowells@redhat.com>, linux-mm@kvack.org,
 Huang Rui <ray.huang@amd.com>, David Airlie <airlied@gmail.com>,
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 Maxime Ripard <mripard@kernel.org>, Rodrigo Vivi <rodrigo.vivi@intel.com>,
 linux-sgx@vger.kernel.org, Jarkko Sakkinen <jarkko@kernel.org>,
 keyrings@vger.kernel.org, Daniel Vetter <daniel@ffwll.ch>,
 linux-fsdevel@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>,
 Christian Koenig <christian.koenig@amd.com>,
 Chandan Babu R <chandan.babu@oracle.com>
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On Wed, Jan 10, 2024 at 12:37:18PM +0000, Matthew Wilcox wrote:
> On Wed, Jan 10, 2024 at 10:21:07AM +0100, Christoph Hellwig wrote:
> > Hi all,
> > 
> > Darrick reported that the fairly new XFS xfile code blows up when force
> > enabling large folio for shmem.  This series fixes this quickly by disabling
> > large folios for this particular shmem file for now until it can be fixed
> > properly, which will be a lot more invasive.
> > 
> > I've added most of you to the CC list as I suspect most other users of
> > shmem_file_setup and friends will have similar issues.
> 
> The graphics users _want_ to use large folios.  I'm pretty sure they've
> been tested with this.  It's just XFS that didn't know about this
> feature of shmem.

At least sgx has all kinds of PAGE_SIZE assumptions.  I haven't audited
(and am probably not qualified to) audit that code, so I wanted to send
a headsup to everyone.