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 51AD619DFA7 for ; Wed, 8 Jan 2025 05:11:56 +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=1736313116; cv=none; b=M6MS4y0sV1DIoUCZpNwThwousqi6JIRH5KTAvI9J5qG5VfQUa54E/oW7TfMdr29RiveSjP0RaDyAJcYlBvSV0NVG6CF7Knp7YlX0BNwUlB89LFXiHmB1muJ69RqK3DOXP/MOQgYKzmQJNMfBk2e9/xDZh8Ld4MtA8wXtndY/HQk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736313116; c=relaxed/simple; bh=5KpxhkySZiULlW13tJLNtzMCheiSh8i7gl8Q9s5OMYs=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=JqSpS/O+crgKNNR95pLvFuHsFUvJEwxTTdWFFTN5ecbiNX5P23RAVrCXc9zXzPmpJfxXz3CIcImsPQ4Xa5GoW+UYPkagdyQruEfwOYR1dN25FW7EVXCKP5VMJxVMakX4ZeoQNgir6+OjabPBjoIify0eUFTbN7FTBLsPxD2unZY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=V4mIATOi; 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="V4mIATOi" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 62339C4CED0; Wed, 8 Jan 2025 05:11:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1736313116; bh=5KpxhkySZiULlW13tJLNtzMCheiSh8i7gl8Q9s5OMYs=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=V4mIATOi3XvARuoSXS/jJ/R48zjerfKB6kYlF62KobXWeHrNxvQ8rLdki9mbk86em 80Pe/e1ghLQaC68uqrHeUB84OIYSHIbZw/1PFJntvXCsG4ZFk3kVJpv6JuJAPQ1u0r Sxy9z8qsfoJqgzPkq4p70W0Rg3FR1o9NtD2SSDQj7bLxXXvpKkCrMwtSDNckiRwSPn F6U91un84D9HzcqR3Au+jbDBMExtWCStsg8ukkOdRM3tFXZTj4IQ6d5hE8ipp3mgLQ q5/TT83de2/G3AOUuaVOIu1UM0sva6cI/TlZvrnokPDSjvOGD7dXsXfmltQQ2As4dH s8ZsHu0PWdgHg== Message-ID: <3635a8f9-e4fa-434b-aeee-95477ed4f6e8@kernel.org> Date: Wed, 8 Jan 2025 14:11:10 +0900 Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 0/2] New zoned loop block device driver To: Jens Axboe , Christoph Hellwig Cc: linux-block@vger.kernel.org References: <20250106142439.216598-1-dlemoal@kernel.org> <2f7c9abe-a23f-4b2f-99aa-e6d220c74dd0@kernel.dk> <20250106152118.GB27324@lst.de> <98be988f-5f6a-489d-b0e1-2f783c5b8a32@kernel.dk> <20250106153252.GA27739@lst.de> <0f2eea00-e5e9-4cd1-8fe6-89ed0c2b262b@kernel.dk> <20250106154433.GA28074@lst.de> <5f57ff26-2c87-45fa-bb91-4f68492bac85@kernel.dk> <606367a7-9bb5-48e5-a7ef-466eefd833fb@kernel.org> <3a1314db-ed44-4c22-8fc1-0cf672003026@kernel.dk> From: Damien Le Moal Content-Language: en-US Organization: Western Digital Research In-Reply-To: <3a1314db-ed44-4c22-8fc1-0cf672003026@kernel.dk> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 1/8/25 6:08 AM, Jens Axboe wrote: >> A kernel-based implementation is simpler and the configuration >> interface literally needs only a single echo bash command to add or >> remove devices. This allows minimal VM configurations with no >> dependencies on user tools/libraries to run these zoned devices, which >> is what we wanted. >> >> I completely agree about the user-space vs kernel tradeoff you >> mentioned. I did consider it but the code simplicity and ease of use >> in practice won for us and I chose to stick with the kernel driver >> approach. >> >> Note that if you are OK with this, I need to send a V2 to correct the >> Kconfig description which currently shows an invalid configuration >> command example. > > Sure, I'm not totally against it, even if I think the arguments are > very weak, and in some places also just wrong. It's not like it's a > huge driver. I am not going to try contesting that our arguments are somewhat weak. Yes, if we spend enough time on it, we could eventually get something workable with ublk. But with that said, when you spend your days developing and testing stuff for zoned storage, having a super easy to use emulation setup for VMs without any userspace dependencies does a world of good for productivity. That is a strong argument for those involved, I think. So may I send V2 for getting it queued up ? -- Damien Le Moal Western Digital Research