From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BE50A29A9FE for ; Tue, 4 Nov 2025 12:23:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762259036; cv=none; b=mZO/RjwGpEVCAryeq0A9P3Qw4Cxf2pqT1b4OoGJ5qWyf015QOURKHwNRHe1lNIpqmwpGcy4fF9XYBysQsQWWSv9FC5cHJm9r1P6WmcotVG9SP41/M9M3LUu02T+JDENNYyipWHKscVuQgMDyvv4zgUAe+/OfnRoHDhSYMFqJ0i8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762259036; c=relaxed/simple; bh=OaulnFfIv9hYj/nauRuDYbAuQXPylBEP9GcGHpiUvAk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=WxgRtamgRZKJcddAfGWydOgxJmBeg9pVCKgShZCoQFmBXA0nbGaeb5hdaROEStlQCpe2v4Z66hd/zwk/B2ewufLL2/TyKfJmSPnbblbuEtZXQBQ8mlLG5N4U5NNf+LWhp78ts7c5sZESE93gLgWTERRkz5EgEGgFgtgE2X1pdu8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=K9Fi45Ya; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="K9Fi45Ya" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C9585C4CEF7; Tue, 4 Nov 2025 12:23:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1762259036; bh=OaulnFfIv9hYj/nauRuDYbAuQXPylBEP9GcGHpiUvAk=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=K9Fi45YagBaVytfPhJw99wYzHfVNhv98n74R+fFiWU8QxYsDvSsWBlIN6UqHzHzDM EgagJn9KmmEi3ffbOXmcBMdPe+pwuq0fNlDsVtL3DxfEpg3PzU7uT6lUGHhQ4wbX+N b2Ou5E1SOeTf7/myN14KvVyiJtH9HLgtOmmbUInr6fjXIq97H4IetxHdkF4I2tt5dN 3x/Uq3dQdVTZR+i6g01hAO0DkOSj6LnZuGrpJohlethDz4iBq2jV0w8SR+mlavFOPl BhQTVhIVgdWIVRifdPNl83Upz+rjhgt6glK2tfydNYBic9UqNyuxaKKo4uhajRvBTq uiQSXFDi0MWGA== Message-ID: <52e064b1-819a-47b3-9f4e-7ab0890841e7@kernel.org> Date: Tue, 4 Nov 2025 13:23:49 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 0/4] mm/userfaultfd: modulize memory types To: Mike Rapoport Cc: Peter Xu , Lorenzo Stoakes , "Liam R. Howlett" , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Muchun Song , Nikita Kalyazin , Vlastimil Babka , Axel Rasmussen , Andrew Morton , James Houghton , Hugh Dickins , Michal Hocko , Ujwal Kundur , Oscar Salvador , Suren Baghdasaryan , Andrea Arcangeli , conduct@kernel.org References: <7768bbb5-f060-45f7-b584-95bd73c47146@kernel.org> <5f128cbf-7210-42d9-aca1-0a5ed20928c2@kernel.org> From: "David Hildenbrand (Red Hat)" Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 04.11.25 08:21, Mike Rapoport wrote: > On Mon, Nov 03, 2025 at 10:27:05PM +0100, David Hildenbrand (Red Hat) wrote: >> >> And maybe that's the main problem here: Liam talks about general uffd >> cleanups while you are focused on supporting guest_memfd minor mode "as >> simple as possible" (as you write below). > > Hijacking for the technical part for a moment ;-) What?! That's crazy :P > > It seems that "as simple as possible" can even avoid data members in struct > vm_uffd_ops, e.g something along these lines: Right, that's certainly even more "minimal". In the end I agree with previous assessment that the original series is not completely a "modulize memory types". If we want to make it easier for guest_memfd to support MFILL_ATOMIC_CONTINUE, then maybe we should focus on that, and only that, for the time being to make progress. -- Cheers David