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=-5.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 19FD5C10F27 for ; Tue, 10 Mar 2020 16:57:58 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id E068D21D7E for ; Tue, 10 Mar 2020 16:57:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="me349UZg" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E068D21D7E 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=bombadil.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=UDVAsv76Xf7u1cCNS95wma/Q89zn24Fh37Wc93I8+nM=; b=me349UZg1k+9XW EEwlGvCJabdBwCVH4xYFRgtfi3AolFFtWC3ZM/R1V+QFTCR2OKEmPNHer1y9BQiKPwGal52l7ZTKx ORLH+0TvCzvnSUip+ruHr8Rpq4tB7W5m6Hqhd54Y1ugDfafq49RmiIxwjOqQJh/4bsqe4lKFME1f8 5YuRZBa3J94ZZQoSBiWG6y0L5BFb3FJD+amB2XThzEO8HlNridS8teDzYeVL/vnab5m9IezRVKZBL vJ3cH9pR40hMwhppMZouZJ7Ov76yj0y3yGdPMKgY420LhVNv2GFaDjFzml4Lb4gDmTd2qJh6Komq+ PDVVK7hrJZCUbnANH0Xg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jBiCa-0002tC-IN; Tue, 10 Mar 2020 16:57:56 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jBiCW-0002sq-Uq for linux-nvme@lists.infradead.org; Tue, 10 Mar 2020 16:57:55 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 22ABF68BE1; Tue, 10 Mar 2020 17:57:51 +0100 (CET) Date: Tue, 10 Mar 2020 17:57:50 +0100 From: Christoph Hellwig To: Keith Busch Subject: Re: [PATCHv2 2/3] nvme-pci: Remove two-pass completions Message-ID: <20200310165750.GB7114@lst.de> References: <20200304181246.481835-1-kbusch@kernel.org> <20200304181246.481835-3-kbusch@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200304181246.481835-3-kbusch@kernel.org> 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-20200310_095754_058847_03344562 X-CRM114-Status: UNSURE ( 7.87 ) X-CRM114-Notice: Please train this message. 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: bijan.mottahedeh@oracle.com, hch@lst.de, linux-nvme@lists.infradead.org, sagi@grimberg.me 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 Wed, Mar 04, 2020 at 10:12:45AM -0800, Keith Busch wrote: > Completion handling had been done in two steps: find all new completions > under a lock, then handle those completions outside the lock. This was > done to make the locked section as short as possible so that other > threads using the same lock wait less time. > > The driver no longer shares locks during completion, and is in fact > lockless for interrupt driven queues, so the optimization no longer > serves its original purpose. Replace the two-pass completion queue > handler with a single pass that completes entries immediately. > > Signed-off-by: Keith Busch Looks good, Reviewed-by: Christoph Hellwig _______________________________________________ linux-nvme mailing list linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme