Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933479Ab3GDVct (ORCPT ); Thu, 4 Jul 2013 17:32:49 -0400 Received: from shards.monkeyblade.net ([149.20.54.216]:50912 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756902Ab3GDVcs (ORCPT ); Thu, 4 Jul 2013 17:32:48 -0400 Date: Thu, 04 Jul 2013 14:32:46 -0700 (PDT) Message-Id: <20130704.143246.1946946036139459725.davem@davemloft.net> To: eric.dumazet@gmail.com Cc: Ian.Campbell@citrix.com, joe.jin@oracle.com, alex@alex.org.uk, frank.blaschka@de.ibm.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, zheng.x.li@oracle.com, xen-devel@lists.xen.org, JBeulich@suse.com, stefano.stabellini@eu.citrix.com, konrad.wilk@oracle.com Subject: Re: kernel panic in skb_copy_bits From: David Miller In-Reply-To: <1372932730.4979.96.camel@edumazet-glaptop> References: <1372930465.4979.82.camel@edumazet-glaptop> <1372931565.7184.32.camel@kazak.uk.xensource.com> <1372932730.4979.96.camel@edumazet-glaptop> X-Mailer: Mew version 6.5 on Emacs 24.1 / Mule 6.0 (HANACHIRUSATO) 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: 614 Lines: 15 From: Eric Dumazet Date: Thu, 04 Jul 2013 03:12:10 -0700 > It looks like a typical COW issue to me. Generically speaking, if we have to mess with page protections this eliminates the performance gain from bypass/zerocopy/whatever that these virtualization layers are doing. But there may be other factors involved which might mitigate that. -- 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/