From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 96957E7717F for ; Thu, 12 Dec 2024 06:06:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=az2n4vRYsU266VQZUHWqUaGY9kt1sehPp2g8jjX1AoU=; b=YL8N8Wa3v7yrm/ciq+tng68nOJ w0X63RTMzlb5u1002+5wBPVswjhE21aBnE7/yjH29nv9QUKvyDfdP9bl+d7Gr/OTifLE67pqPwuDT H/ssgey/1UuqJD63Sl0OdqtNZcCvcZc47WXAbmpi6jDreGa8SX7pm67wm3kpaNfvVZz11G+bqKtnC EpagSdGJo4Pnr0Ya8qD+yDljShLYGv+E4tbduSDGSfvNnhiPq+XnLvl0rVAE/DQTFXHaf8jnkoVsJ UXMW0j3w+gfbRRw/PMVPgUXk6iJAqYTxoOykf+oHrxa7QOdnbyO/1d/zZ+XLiLB1WAKtU3R8Z20xu OZ2IUVGA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tLcKr-0000000H08m-44E3; Thu, 12 Dec 2024 06:06:05 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tLcKp-0000000H08L-21Cw for linux-nvme@lists.infradead.org; Thu, 12 Dec 2024 06:06:04 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id BF4A268D07; Thu, 12 Dec 2024 07:05:58 +0100 (CET) Date: Thu, 12 Dec 2024 07:05:58 +0100 From: Christoph Hellwig To: Kanchan Joshi Cc: Christoph Hellwig , Keith Busch , axboe@kernel.dk, linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, linux-fsdevel@vger.kernel.org, io-uring@vger.kernel.org, sagi@grimberg.me, asml.silence@gmail.com, anuj20.g@samsung.com, Keith Busch Subject: Re: [PATCHv13 00/11] block write streams with nvme fdp Message-ID: <20241212060558.GA5266@lst.de> References: <20241210194722.1905732-1-kbusch@meta.com> <20241211071350.GA14002@lst.de> 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) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241211_220603_659725_294F35B0 X-CRM114-Status: GOOD ( 18.69 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Thu, Dec 12, 2024 at 11:21:07AM +0530, Kanchan Joshi wrote: > On 12/11/2024 12:43 PM, Christoph Hellwig wrote: > > The changes looks good to me. I'll ty to send out an API for querying > > the paramters in the next so that we don't merge the granularity as dead > > code > > What do you have in mind for this API. New fcntl or ioctl? > With ability limited to querying only or.... Yes, new fcntl or ioctl, query the number of streams and (nominal) stream granularity as a start. There is a few other things that might be useful: - check if the size is just nominal or not, aka if the device can shorten it. FDP currently allows for that, but given that notifications for that are out of bounds it makes a complete mess of software actually trying to use it for more than simple hot/cold separation like cachelib, so we find a way to query that in the spec. - reporting of the remaining capacity per stream, although I'm not sure if that should be in the same ioctl/fcntl, or better done using a separate interface that has the stream number as input and the capacity as out, which would seem a lot simpler