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Date:   Wed, 7 Aug 2019 08:30:02 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Hugh Dickins <hughd@google.com>
Cc:     Al Viro <viro@zeniv.linux.org.uk>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Jani Nikula <jani.nikula@linux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@intel.com>,
        Chris Wilson <chris@chris-wilson.co.uk>,
        David Howells <dhowells@redhat.com>,
        Christoph Hellwig <hch@lst.de>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCHv2 2/3] i915: convert to new mount API
Message-ID: <20190807063002.GG6627@lst.de>
References: <20190805160307.5418-1-sergey.senozhatsky@gmail.com> <20190805160307.5418-3-sergey.senozhatsky@gmail.com> <20190805181255.GH1131@ZenIV.linux.org.uk> <20190805182834.GI1131@ZenIV.linux.org.uk> <alpine.LSU.2.11.1908060007190.1941@eggly.anvils>
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On Tue, Aug 06, 2019 at 12:50:10AM -0700, Hugh Dickins wrote:
> Though personally I'm averse to managing "f"objects through
> "m"interfaces, which can get ridiculous (notably, MADV_HUGEPAGE works
> on the virtual address of a mapping, but the huge-or-not alignment of
> that mapping must have been decided previously).  In Google we do use
> fcntls F_HUGEPAGE and F_NOHUGEPAGE to override on a per-file basis -
> one day I'll get to upstreaming those.

Such an interface seems very useful, although the two fcntls seem a bit
odd.

But I think the point here is that the i915 has its own somewhat odd
instance of tmpfs.  If we could pass the equivalent of the huge=*
options to shmem_file_setup all that garbage (including the
shmem_file_setup_with_mnt function) could go away.