Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754542Ab0DIFnL (ORCPT ); Fri, 9 Apr 2010 01:43:11 -0400 Received: from mail.vyatta.com ([76.74.103.46]:39277 "EHLO mail.vyatta.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752291Ab0DIFnJ (ORCPT ); Fri, 9 Apr 2010 01:43:09 -0400 Date: Thu, 8 Apr 2010 17:52:25 -0700 From: Stephen Hemminger To: "Xin, Xiaohui" Cc: "netdev@vger.kernel.org" , "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "mingo@elte.hu" , "mst@redhat.com" , "jdike@c2.user-mode-linux.org" , "davem@davemloft.net" Subject: Re: [RFC] [PATCH v2 3/3] Let host NIC driver to DMA to guest user space. Message-ID: <20100408175225.7577af19@nehalam> In-Reply-To: <97F6D3BD476C464182C1B7BABF0B0AF5C17B5C2A@shzsmsx502.ccr.corp.intel.com> References: <1270193410-6877-1-git-send-email-xiaohui.xin@intel.com> <20100402085556.75a8ff7c@nehalam> <97F6D3BD476C464182C1B7BABF0B0AF5C17B5C2A@shzsmsx502.ccr.corp.intel.com> Organization: Vyatta X-Mailer: Claws Mail 3.7.5 (GTK+ 2.18.3; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 876 Lines: 18 On Tue, 6 Apr 2010 14:26:29 +0800 "Xin, Xiaohui" wrote: > >How do you deal with the DoS problem of hostile user space app posting huge > >number of receives and never getting anything. > > That's a problem we are trying to deal with. It's critical for long term. > Currently, we tried to limit the pages it can pin, but not sure how much is reasonable. > For now, the buffers submitted is from guest virtio-net driver, so it's safe in some extent > just for now. It is critical even now. Once you get past toy benchmarks you will see things like Java processes with 1000 threads all reading at once. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/