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=-2.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 B351CC432C0 for ; Fri, 29 Nov 2019 16:27:32 +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 864EE21736 for ; Fri, 29 Nov 2019 16:27:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="OxvY73OG"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="IvjfeG/h" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 864EE21736 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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=/YHkMYO/UXU7YYcF5JBpazc0gK3JCwkgwjNfQRc6T2o=; b=OxvY73OG+S02t3 lTGP1VjT5nhF5h6zbzaigGKJMkO8C2k6rcAbL9hyDXkFNOmRgahw/Pbx4JzmvmrnwACMiTlMXnlw2 e2hAfR9VUWLGTcxcjrIKSvbJx3dOZNwewbOHH+QnU7nkjOWQC8ujIfsNAT8K373v3sXRpAsVCpc6V yLx/8ECByuCH9TyOGVtdSa0oyq3oN8kp23DCdoqiNEHY0OXxyHV1SZuUi8HfycQIY7UenkplJMSqM E6ESajZgNvyrETo7pvmdl8nwmTJ1Au5anYdJci8x5q4QT08i98vbV/n53Bw3U/v5/UUOWiS4a4nNC vHE5XfEVQFkF6fsYF2Wg==; 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 1iaj78-0000hE-NP; Fri, 29 Nov 2019 16:27:26 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1iaj75-0000gv-IG for linux-nvme@lists.infradead.org; Fri, 29 Nov 2019 16:27:24 +0000 Received: from C02WT3WMHTD6.lpcnextlight.net (unknown [161.97.246.164]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 00D0121736; Fri, 29 Nov 2019 16:27:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575044842; bh=PtXZBX2tJ7ZFj2m9poMD4MEvE99te2flrdbx/lBsEIc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=IvjfeG/hdSzSG5sWiI3xcKznK6dNXgAuyOBE9c89M3rNmQ9JidCPVD+IYk3G/uOTF YKdtG1tjPBwGOoeATTWBWqYW2JbOQuTZQfisxQh4TD4nDoPo3wZlnML7eBtM374pKF B4XU45T9Oz0V+xWhIgPyIKd2Aq+pqhXA+g91GbrA= Date: Fri, 29 Nov 2019 09:27:19 -0700 From: Keith Busch To: Sebastian Andrzej Siewior Subject: Re: [PATCH 0/4] nvme: Threaded interrupt handling improvements Message-ID: <20191129162719.GA47681@C02WT3WMHTD6.lpcnextlight.net> References: <20191127175824.1929-1-kbusch@kernel.org> <20191129094640.6fq6wcxmfi4fwnlw@linutronix.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20191129094640.6fq6wcxmfi4fwnlw@linutronix.de> User-Agent: Mutt/1.12.1 (2019-06-15) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191129_082723_622428_FAA4DE00 X-CRM114-Status: GOOD ( 11.59 ) 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: ming.lei@redhat.com, helgaas@kernel.org, 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 Fri, Nov 29, 2019 at 10:46:40AM +0100, Sebastian Andrzej Siewior wrote: > On 2019-11-28 02:58:20 [+0900], Keith Busch wrote: > > Threaded interrupts allow the device to continue sending interrupt > > messages while the driver is handling the previous notification. This > > can cause a significant amount of CPU cycles unnecessarily spent in hard > > irq context, and potentially triggers spurious interrupt detection to > > disable the nvme interrupt. > > Thank you for looking into this. > To be clear: the "spurious interrupt detector" won't do a thing if you > never return IRQ_NONE. As long as you return IRQ_HANDLED, everything is > fine. That's not entirely accurate. We have to return IRQ_WAKE_THREAD from the hardirq handler, which gets converted to IRQ_NONE if desc->threads_handled hasn't changed and considered spurious. If the threaded handler runs sufficiently long, desc->threads_handled won't get updated frequently enough, so this series fixes that for nvme by masking the interrupt in the device, preventing future hard irq callbacks. _______________________________________________ linux-nvme mailing list linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme