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 C4848C25B50 for ; Mon, 23 Jan 2023 18:02:34 +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=HcBEZbBiHfm+jffmTNnSQ6lXYGZsrGLOKhJIRTiA7Cc=; b=Q4+Hw2GcANGmmdihtaafIUBfRb O8BRD/mub5s2Hf5z3NXp2alwwG9wHkc0jLwKGEKc7LU6x5hXc32CfJtnnonV9Vl/PA0hSDTM2za8U k7yrVROHycUcmcS2leQfqoQ25ysblP1uRwu0oymWBaT/0LJ2mwaUL0lMMe5nsOZ4WSSyb+PX6uowB Q8pVQ2iiNQJFQTYOrd+k7Q4w53pCPnYKXDFQmEk+BQEx2tFrgBRGTq13MiwM8DvviU+ruUnsQ5n8o epCbJVmFJY8TLSyUDB4IzbvehqFZx501sW7p7nyziBAI3lxYwQFNsN70HGSFNF0N3KnfluMR/dC4s RjxIj5QQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1pK19M-000wkc-5O; Mon, 23 Jan 2023 18:02:32 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1pK19J-000wjO-5Q for linux-nvme@lists.infradead.org; Mon, 23 Jan 2023 18:02:30 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 60FC868C7B; Mon, 23 Jan 2023 19:02:20 +0100 (CET) Date: Mon, 23 Jan 2023 19:02:19 +0100 From: Christoph Hellwig To: Keith Busch Cc: Christoph Hellwig , Kanchan Joshi , Keith Busch , linux-nvme@lists.infradead.org, sagi@grimberg.me Subject: Re: [PATCHv2] nvme: always initialize known command effects Message-ID: <20230123180219.GB13872@lst.de> References: <20230119164128.2159217-1-kbusch@meta.com> <20230123102431.GA11000@green5> <20230123163536.GA7699@lst.de> <20230123163819.GA8009@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-20230123_100229_382999_7BC639D0 X-CRM114-Status: GOOD ( 14.23 ) 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 Mon, Jan 23, 2023 at 10:42:45AM -0700, Keith Busch wrote: > xarray lookups are pretty slow in comparison, though. This is in a fast > path now, so I think we need to keep caching it. Is it? > Alternatively, we could replace the xarray with a normal array sized to > highest seen CSI. Realisitically, I don't think we'll see a CSI higher > than 3 any time soon, so it wouldn't take up much space. The problem is that we lose the extensibility to arbitrary command sets for the ng devices. So if the xarray performance is a problem let's not waste any time on this idea.