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 D30E9189B8F; Thu, 3 Oct 2024 12:51:16 +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=1727959878; cv=none; b=gKzik29sd1God4XTJshoNTzcSH0wfTcMHBXfTxI6sn0NzIJ6IhhZKdP1sx+3BDCxFImVxByjPL5ZnhqgwDeiwrKiJ7XyMumEPPdPeIhBpP+glKYp9CThoumwJ315mcSQ9jgN6PF05Fqn35bCYBQXE3Vot5w1OYyiNYI2YBJWZgc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727959878; c=relaxed/simple; bh=heWLThp1SIOOMZuyRB4fwRQe+xfjAg3wDPh+zMqxVO4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=nelfNF2G2ouWe5OO0Mjfe67LCeiqOWo7SEpig9bQaFu9jXnH/y8jHfUTWcVSD2wsH8Jt+aHd1/vfeprK3GDMGxCfywKSKUhGZ0+2mZLl2ksI6QqZO8uvj9qu55vF/G3mBnQhtyqBppKQqXZeSGs3OLSiF6uSt+Xju70KM+HFAoA= 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 C6AE6227A88; Thu, 3 Oct 2024 14:51:10 +0200 (CEST) Date: Thu, 3 Oct 2024 14:51:10 +0200 From: Christoph Hellwig To: Keith Busch Cc: Christoph Hellwig , Jens Axboe , Kanchan Joshi , hare@suse.de, sagi@grimberg.me, martin.petersen@oracle.com, 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, javier.gonz@samsung.com Subject: Re: [PATCH v7 0/3] FDP and per-io hints Message-ID: <20241003125110.GA17031@lst.de> References: <20240930181305.17286-1-joshi.k@samsung.com> <20241001092047.GA23730@lst.de> <99c95f26-d6fb-4354-822d-eac94fdba765@kernel.dk> <20241002075140.GB20819@lst.de> <20241002151344.GA20364@lst.de> <20241002151949.GA20877@lst.de> Precedence: bulk X-Mailing-List: linux-fsdevel@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 02, 2024 at 09:33:16AM -0600, Keith Busch wrote: > You remember right. I also explained the use cases for per-io hints are > to replace current passthrough users with generic read/write paths that > have all the memory guard rails, read/write stats, and other features > that you don't get with passthrough. This just lets you accomplish the > same placement hints with the nvme raw block device that you get with > the nvme char device. Yes, and as I said before we need an opt-in from the file_ops, because file systems can't support this. And I'm speaking that from a position of working on a file system that made the existing non-idea hints work (to all fairness Hans did the hard work, but I was part of it).