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 CFEB6C5ACD3 for ; Fri, 20 Feb 2026 16:12:05 +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=1resjWaJSCEUllD7tudAjnOTFNXskt/Sc9klyHjt2mA=; b=uzkBe8stxUfQFPmdI9Ex8s9ZJg 4Jsq4pWXuGGFx0e7WXiMCmG+LxOzO/Bh59jl6zpwnc+PEYOuyG24nDIZlDHjqChxmRHiCBIiP8gMe ieVwcsuDN6SrXelPujLUd8/QYEDIg/9f60/TZs2F2t+VdyGLc2UDMI3UCfp3wen9mgPbPzCKwrwcI MCe7FqkbZdJBnluCwgA0/hIqqCzRNP1x10uGCn64aKWVP8107c1OGApJYTXZMmUYVi1uZiBvFzqtl yLtOlA3lWwp+YU+tiBDYKkHliZuIUiDvyNbZokewVA354y1bNq7Iqpwz1P1PZsdlZs6+JxUGgKcO4 mbB5uUAQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vtT6q-0000000FCzc-1Mf9; Fri, 20 Feb 2026 16:12:04 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vtT6k-0000000FCv0-1Zns for linux-nvme@lists.infradead.org; Fri, 20 Feb 2026 16:12:02 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 4DA9568D05; Fri, 20 Feb 2026 17:11:56 +0100 (CET) Date: Fri, 20 Feb 2026 17:11:55 +0100 From: Christoph Hellwig To: Caleb Sander Mateos Cc: Keith Busch , Jens Axboe , Christoph Hellwig , Sagi Grimberg , Chaitanya Kulkarni , linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 6/6] nvmet: report NPDGL and NPDAL Message-ID: <20260220161155.GG15071@lst.de> References: <20260220032809.758089-1-csander@purestorage.com> <20260220032809.758089-7-csander@purestorage.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260220032809.758089-7-csander@purestorage.com> 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-20260220_081158_573372_41001D8A X-CRM114-Status: GOOD ( 13.15 ) 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, Feb 19, 2026 at 08:28:09PM -0700, Caleb Sander Mateos wrote: > A block device with a very large discard_granularity queue limit may not > be able to report it in the 16-bit NPDG and NPDA fields in the Identify > Namespace data structure. For this reason, version 2.1 of the NVMe specs > added 32-bit fields NPDGL and NPDAL to the NVM Command Set Specific > Identify Namespace structure. So report the discard_granularity there > too and set OPTPERF to 11b to indicate those fields are supported. >From a pure mechanics point of view this looks fine. I'll not that actually aligning the discard to these granularities probably won't really work for most file systems, though.