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 X-Spam-Level: X-Spam-Status: No, score=-6.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2F105C4727C for ; Tue, 29 Sep 2020 18:30:24 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 40596208B8 for ; Tue, 29 Sep 2020 18:30:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="fmbMt4cJ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 40596208B8 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=s/ZseG+z7usktRIJyfkivtReOMJcrnWs2jWUK11jgHE=; b=fmbMt4cJW9Ab1G5nKhEuWbAgo Ww5fj+o6m9Cxe+XG/upR3/kDwzQPbQvm1QSBYyGWAxUM43IlXsTebPggNTCoDpySz5OT8NDSI29dS jkLVWjgUi02UJmPE16Nyopic+AJhGuhfYsz9HTfhpQep75dklTUEVPfjFhu1yyyz4L41IAuSvLcFl XquDNnl33jzW605mDhYgFSXGRI3O9ZJ7dXCPY9zQsO00KEq+315OciPnq/o+EXVdJqX5VZtWiZoEE uCGY/Y1sLVNk8mSiHv5ycgzyz1Erhy412245kXbfFPwYSgPxfbeI4w2YvFqeDobl9n0b5hVOEBO9T PVikb5WPQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kNKOJ-00041L-6V; Tue, 29 Sep 2020 18:30:19 +0000 Received: from verein.lst.de ([213.95.11.211]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kNKOG-00040t-OW for linux-nvme@lists.infradead.org; Tue, 29 Sep 2020 18:30:17 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 4774867373; Tue, 29 Sep 2020 20:30:15 +0200 (CEST) Date: Tue, 29 Sep 2020 20:30:14 +0200 From: Christoph Hellwig To: Sagi Grimberg Subject: Re: [PATCH 08/20] nvme: call nvme_identify_ns as the first thing in nvme_alloc_ns_block Message-ID: <20200929183014.GC12948@lst.de> References: <20200928123502.435373-1-hch@lst.de> <20200928123502.435373-9-hch@lst.de> <19d74cf6-cc55-e7aa-ab01-e8561ef23be2@grimberg.me> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <19d74cf6-cc55-e7aa-ab01-e8561ef23be2@grimberg.me> 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-20200929_143016_907938_48FF24F6 X-CRM114-Status: GOOD ( 11.39 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Keith Busch , Jens Axboe , Damien Le Moal , Christoph Hellwig , linux-nvme@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Tue, Sep 29, 2020 at 01:39:31AM -0700, Sagi Grimberg wrote: > >> Check if the namespace actually exists as the very first thing and don't >> bother with any extra work if not. This should speed up and simplify >> the sequential scanning for NVMe 1.0 devices. > > What exactly is this speeding up? Its just a few assignments+allocations Yes, that is all. Although some of the block layer teardown can be a little more costly with various atomics. Nothing really major, but just simple work avoidance for a non-failure early exit path. _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme