From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3FB356D18 for ; Tue, 1 Aug 2023 23:46:06 +0000 (UTC) Received: from mail-qk1-x72c.google.com (mail-qk1-x72c.google.com [IPv6:2607:f8b0:4864:20::72c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9E055E48 for ; Tue, 1 Aug 2023 16:46:05 -0700 (PDT) Received: by mail-qk1-x72c.google.com with SMTP id af79cd13be357-76c7eb57c0bso327340085a.2 for ; Tue, 01 Aug 2023 16:46:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; t=1690933565; x=1691538365; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=KBKGP+rOQrE0yI33WFL70QQXfWqUPCJII6/ruXV7a18=; b=SWXVXrgm7uYZHZpxzUnYKGRlHWgX0IK0Rnlpt7cDr5IAkGjYP2UkjUfjYQGOZNR6qJ LJgCwO55lyoYtyX6E3Q4s40xhlJi1dKPH0AZpIy8isp0s8rC0ju8u3sjUbibjy6jNmr+ mcJOcMWuV5sswR+4lXv+R2JNNPJMLL1UAxV+nc9eXFABT8+j+4Fr4O92HGXMdw8ZW/cO tYSdLgE9sYsL2LpWr9Lpjtw96tubbaY6Lk9BRgEa7XCIyKeCZkvIgI1OH2+pWauTOwMU tjTG/lngwIPwA8M8k3ptItHteXjaC4SjLv7Eqa1WLuIH7QiFLFw+WP+vp7HZAj1aZd8b Tmdw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690933565; x=1691538365; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=KBKGP+rOQrE0yI33WFL70QQXfWqUPCJII6/ruXV7a18=; b=Ye8WoaMprpj3O8qzgSnzWniW9/5+W5L5btCRFImf+N6LLrOfu5oi5YerytuuZ/i8UK m9aTtMIRuFMtDS4h4DGKxQVHvh7XOA0slxySN+4BkxgSdVw4Isv0l8wkS4Yz5MSKo2O8 Zu4XnIyJB043qyPnmon3yN0QM0jFvl47FY1gVngnw5HzWuDPQ/0sBoikhpleF0Am41Fv OfvM0zD2J4aETz++4ph4/Lx9ZRsYZT+usWDOsUwqTLciIfwWVE5mqSqqif0cwlOtAGgV KNei6EVzO1kezqJShG8Evl4ZEY9MMcLERdKzHYIUiGv7CB6YbomkIHsTGnoFrNVgqU/B pHuA== X-Gm-Message-State: ABy/qLZoxRblq/10IuQJOMknLxKThpHValXkR9SmTha/H/hX+DF/3Jlt 0RE6l1WUMYLBZspERU6gF3vd7Q== X-Google-Smtp-Source: APBJJlGxnpoNiNKnO6qXw0UeYYlZ6fEaFr61aQgxxSleH8rfkxM6Fg0dXraa5FyNSubaYwh/wMlyfw== X-Received: by 2002:a05:620a:4010:b0:76c:bf54:70ab with SMTP id h16-20020a05620a401000b0076cbf5470abmr5499429qko.12.1690933564773; Tue, 01 Aug 2023 16:46:04 -0700 (PDT) Received: from ziepe.ca (hlfxns017vw-142-68-25-194.dhcp-dynamic.fibreop.ns.bellaliant.net. [142.68.25.194]) by smtp.gmail.com with ESMTPSA id q10-20020ae9e40a000000b007676f3859fasm4543814qkc.30.2023.08.01.16.46.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Aug 2023 16:46:04 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.95) (envelope-from ) id 1qQz3z-002y3w-GJ; Tue, 01 Aug 2023 20:46:03 -0300 Date: Tue, 1 Aug 2023 20:46:03 -0300 From: Jason Gunthorpe To: Long Li Cc: Wei Hu , "netdev@vger.kernel.org" , "linux-hyperv@vger.kernel.org" , "linux-rdma@vger.kernel.org" , Ajay Sharma , "leon@kernel.org" , KY Srinivasan , Haiyang Zhang , "wei.liu@kernel.org" , Dexuan Cui , "davem@davemloft.net" , "edumazet@google.com" , "kuba@kernel.org" , "pabeni@redhat.com" , vkuznets , "ssengar@linux.microsoft.com" , "shradhagupta@linux.microsoft.com" Subject: Re: [PATCH v4 1/1] RDMA/mana_ib: Add EQ interrupt support to mana ib driver. Message-ID: References: <20230728170749.1888588-1-weh@microsoft.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_BLOCKED, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net On Tue, Aug 01, 2023 at 07:06:57PM +0000, Long Li wrote: > The driver interrupt code limits the CPU processing time of each EQ > by reading a small batch of EQEs in this interrupt. It guarantees > all the EQs are checked on this CPU, and limits the interrupt > processing time for any given EQ. In this way, a bad EQ (which is > stormed by a bad user doing unreasonable re-arming on the CQ) can't > storm other EQs on this CPU. Of course it can, the bad use just creates a million EQs and pushes a bit of work through them constantly. How is that really any different from pushing more EQEs into a single EQ? And how does your EQ multiplexing work anyhow? Do you poll every EQ on every interrupt? That itself is a DOS vector. Jason