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=-2.2 required=3.0 tests=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 CC69EC3A5A2 for ; Tue, 3 Sep 2019 07:29:17 +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 9B91F23402 for ; Tue, 3 Sep 2019 07:29:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="rI+LcKgo" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9B91F23402 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com 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=peCqm+MAtuEJy+7qG4/4LiIN1YmXEK4obPCBaP9a7IA=; b=rI+LcKgoU3Yus9 PmDTqMkxtnuoIpZTAhwTFQ9Xc+KMRDsh7x0qAOpv5+k718kNRsDPHu7HxCAr7acCA310i8Hvnwc6U wOQRgBgm3kqxFAyCYz7ZnVIhYgleXDUuD3P1BGS574qFenSAw/NuWxdieMhCHODz79kU0Rg1aDNDa Iw/TjEthZt9o3JRPRM66FA0OVnWJZX7zc7hxRfVU9Nw2FjC3z9VGNZTr2xHnP0B2BYV6+OLgZ3Ipr hJQMe6wsA+00ratpBayaRs5zosaLcXdDkRxvPDVyDGCci539CRGwj0IYV0D1X8KUWSxaSOgYl/ZEZ G5siKxL7FM2Dg9CeDonw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1i53FT-0006EV-Hb; Tue, 03 Sep 2019 07:29:07 +0000 Received: from mx1.redhat.com ([209.132.183.28]) by bombadil.infradead.org with esmtps (Exim 4.92 #3 (Red Hat Linux)) id 1i53FQ-0006DX-NT for linux-nvme@lists.infradead.org; Tue, 03 Sep 2019 07:29:06 +0000 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 1A9EA106E28C; Tue, 3 Sep 2019 07:29:04 +0000 (UTC) Received: from ming.t460p (ovpn-8-25.pek2.redhat.com [10.72.8.25]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D14055D9E1; Tue, 3 Sep 2019 07:28:54 +0000 (UTC) Date: Tue, 3 Sep 2019 15:28:49 +0800 From: Ming Lei To: Daniel Lezcano Subject: Re: [PATCH 1/4] softirq: implement IRQ flood detection mechanism Message-ID: <20190903072848.GA22170@ming.t460p> References: <20190827225827.GA5263@ming.t460p> <20190828110633.GC15524@ming.t460p> <20190828135054.GA23861@ming.t460p> <20190903033001.GB23861@ming.t460p> <299fb6b5-d414-2e71-1dd2-9d6e34ee1c79@linaro.org> <20190903063125.GA21022@ming.t460p> <6b88719c-782a-4a63-db9f-bf62734a7874@linaro.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <6b88719c-782a-4a63-db9f-bf62734a7874@linaro.org> User-Agent: Mutt/1.11.3 (2019-02-01) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.64]); Tue, 03 Sep 2019 07:29:04 +0000 (UTC) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190903_002904_787278_A9A8D014 X-CRM114-Status: GOOD ( 19.63 ) 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: Jens Axboe , Hannes Reinecke , Sagi Grimberg , linux-scsi@vger.kernel.org, Peter Zijlstra , Long Li , John Garry , LKML , linux-nvme@lists.infradead.org, Keith Busch , Ingo Molnar , Thomas Gleixner , Christoph Hellwig 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 03, 2019 at 08:40:35AM +0200, Daniel Lezcano wrote: > On 03/09/2019 08:31, Ming Lei wrote: > > Hi Daniel, > > > > On Tue, Sep 03, 2019 at 07:59:39AM +0200, Daniel Lezcano wrote: > >> > >> Hi Ming Lei, > >> > >> On 03/09/2019 05:30, Ming Lei wrote: > >> > >> [ ... ] > >> > >> > >>>>> 2) irq/timing doesn't cover softirq > >>>> > >>>> That's solvable, right? > >>> > >>> Yeah, we can extend irq/timing, but ugly for irq/timing, since irq/timing > >>> focuses on hardirq predication, and softirq isn't involved in that > >>> purpose. > >>> > >>>> > >>>>> Daniel, could you take a look and see if irq flood detection can be > >>>>> implemented easily by irq/timing.c? > >>>> > >>>> I assume you can take a look as well, right? > >>> > >>> Yeah, I have looked at the code for a while, but I think that irq/timing > >>> could become complicated unnecessarily for covering irq flood detection, > >>> meantime it is much less efficient for detecting IRQ flood. > >> > >> In the series, there is nothing describing rigorously the problem (I can > >> only guess) and why the proposed solution solves it. > >> > >> What is your definition of an 'irq flood'? A high irq load? An irq > >> arriving while we are processing the previous one in the bottom halves? > > > > So far, it means that handling interrupt & softirq takes all utilization > > of one CPU, then processes can't be run on this CPU basically, usually > > sort of CPU lockup warning will be triggered. > > It is a scheduler problem then ? Scheduler can do nothing if the CPU is taken completely by handling interrupt & softirq, so seems not a scheduler problem, IMO. Thanks, Ming _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme