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Date:   Thu, 21 Oct 2021 05:38:29 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     David Hildenbrand <david@redhat.com>
Cc:     Kent Overstreet <kent.overstreet@gmail.com>,
        Christoph Hellwig <hch@infradead.org>,
        Matthew Wilcox <willy@infradead.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        "Kirill A. Shutemov" <kirill@shutemov.name>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Andrew Morton <akpm@linux-foundation.org>,
        "Darrick J. Wong" <djwong@kernel.org>,
        David Howells <dhowells@redhat.com>,
        Hugh Dickins <hughd@google.com>
Subject: Re: Folios for 5.15 request - Was: re: Folio discussion recap -
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On Thu, Oct 21, 2021 at 02:35:32PM +0200, David Hildenbrand wrote:
> My opinion after all the discussions: use a dedicate type with a clear
> name to solve the immediate filemap API issue. Leave the remainder alone
> for now. Less code to touch, less subsystems to involve (well, still a
> lot), less people to upset, less discussions to have, faster review,
> faster upstream, faster progress. A small but reasonable step.

I don't get it.  I mean I'm not the MM expert, I've only been touching
most areas of it occasionally for the last 20 years, but anon and file
pages have way more in common both in terms of use cases and
implementation than what is different (unlike some of the other (ab)uses
of struct page).  What is the point of splitting it now when there are
tons of use cases where they are used absolutely interchangable both
in consumers of the API and the implementation?