From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (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 1F9FC8F6A; Thu, 10 Oct 2024 09:10:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.95.11.211 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728551429; cv=none; b=OVv8uuSaQTsbsHlaCsQ9FHHBD9N28ILlUtr0hObzPZVfU+2jaaYu2kf0lZfRwFHLbgy0/3c1ZZAyEUFwdSQrVU6u0TlQvbu9gkkhWFbj0rXZVjkoV7O+ScdK26rv1D+a/scRTWdnri+7ji9zKc9TgB32viyMlW8/O9wP3JREwsk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728551429; c=relaxed/simple; bh=Eh+gMxTT4mXmQNfcxuxyy5KBpH1alhH2XvStgqjym+o=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=A0rPh/r7Bz/4A4eIVwXWQ61T/hIUASLJYN0yTtsiP9PpadCegDwVuzKmQWbOtR9+EKIjWIOUCcjRloz5dDa+IOBhuPK1j1kCaAtzaCrbIz/NRdsXqpP/YoD+Txg02mEzqRg1ROUyxvbPaJXDZNoZq0psIHvlc3luhfBA6LNONHw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de; spf=pass smtp.mailfrom=lst.de; arc=none smtp.client-ip=213.95.11.211 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=lst.de Received: by verein.lst.de (Postfix, from userid 2407) id E3E20227A8E; Thu, 10 Oct 2024 11:10:21 +0200 (CEST) Date: Thu, 10 Oct 2024 11:10:21 +0200 From: Christoph Hellwig To: Keith Busch Cc: Christoph Hellwig , Javier =?iso-8859-1?Q?Gonz=E1lez?= , Jens Axboe , "Martin K. Petersen" , Kanchan Joshi , hare@suse.de, sagi@grimberg.me, brauner@kernel.org, viro@zeniv.linux.org.uk, jack@suse.cz, jaegeuk@kernel.org, bcrl@kvack.org, dhowells@redhat.com, bvanassche@acm.org, asml.silence@gmail.com, linux-nvme@lists.infradead.org, linux-fsdevel@vger.kernel.org, io-uring@vger.kernel.org, linux-block@vger.kernel.org, linux-aio@kvack.org, gost.dev@samsung.com, vishak.g@samsung.com Subject: Re: [PATCH v7 0/3] FDP and per-io hints Message-ID: <20241010091021.GA9287@lst.de> References: <20241004053121.GB14265@lst.de> <20241004061811.hxhzj4n2juqaws7d@ArmHalley.local> <20241004062733.GB14876@lst.de> <20241004065233.oc5gqcq3lyaxzjhz@ArmHalley.local> <20241004123027.GA19168@lst.de> <20241007101011.boufh3tipewgvuao@ArmHalley.local> <20241008122535.GA29639@lst.de> <20241009092828.GA18118@lst.de> Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) On Wed, Oct 09, 2024 at 09:06:25AM -0600, Keith Busch wrote: > > anything to the reclaim unit? Or is this another of the cases where > > as a hyperscaler you just "know" from the data sheet? > > As far as I know, this is an inconsequential spec detail that is not > being considered by any applications testing this. And yet, the expected > imrpovements are still there, so I don't see a point holding this up for > that reason. It was the whole point of the thing, and a major source of complexity. Although not quite for this use case Hans has numbers that aligning application data tables / objects / etc to the underlying "erase unit" absolutely matters. And just to make it clear the objection here is not that we have an an interface that doesn't take that into respect at the syscall level. We already have that interface and might as well make use of that. The problem is that the series tries to directly expose that to the driver, freezing us into this incomplet interface forever (assuming we have users actually picking it up). That's why I keep insisting like a broken record that we need to get this lower interface right first.