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Message-ID: <20190204161201.GA6840@infradead.org>
Date: Mon, 4 Feb 2019 08:12:01 -0800
From: Christoph Hellwig <hch@...radead.org>
To: Christopher Lameter <cl@...ux.com>
Cc: john.hubbard@...il.com, Andrew Morton <akpm@...ux-foundation.org>,
linux-mm@...ck.org, Al Viro <viro@...iv.linux.org.uk>,
Christian Benvenuti <benve@...co.com>,
Christoph Hellwig <hch@...radead.org>,
Dan Williams <dan.j.williams@...el.com>,
Dave Chinner <david@...morbit.com>,
Dennis Dalessandro <dennis.dalessandro@...el.com>,
Doug Ledford <dledford@...hat.com>, Jan Kara <jack@...e.cz>,
Jason Gunthorpe <jgg@...pe.ca>,
Jerome Glisse <jglisse@...hat.com>,
Matthew Wilcox <willy@...radead.org>,
Michal Hocko <mhocko@...nel.org>,
Mike Rapoport <rppt@...ux.ibm.com>,
Mike Marciniszyn <mike.marciniszyn@...el.com>,
Ralph Campbell <rcampbell@...dia.com>,
Tom Talpey <tom@...pey.com>,
LKML <linux-kernel@...r.kernel.org>,
linux-fsdevel@...r.kernel.org, John Hubbard <jhubbard@...dia.com>
Subject: Re: [PATCH 0/6] RFC v2: mm: gup/dma tracking
On Mon, Feb 04, 2019 at 04:08:02PM +0000, Christopher Lameter wrote:
> It may be worth noting a couple of times in this text that this was
> designed for anonymous memory and that such use is/was ok. We are talking
> about a use case here using mmapped access with a regular filesystem that
> was not initially intended. The mmapping of from the hugepages filesystem
> is special in that it is not a device that is actually writing things
> back.
>
> Any use with a filesystem that actually writes data back to a medium
> is something that is broken.
Saying it was not intended seems rather odd, as it was supported
since day 0 and people made use of it.
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