From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: something is wrong in commit 971f10eca1 - tcp: better TCP_SKB_CB layout to reduce cache line misses Date: Tue, 14 Oct 2014 15:03:00 -0400 (EDT) Message-ID: <20141014.150300.536881166743492994.davem@davemloft.net> References: <543D2435.8090002@winsoft.pl> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: kkolasa@winsoft.pl, eric.dumazet@gmail.com, netdev@vger.kernel.org, edumazet@gmail.com To: cwang@twopensource.com Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:43665 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753866AbaJNTDD (ORCPT ); Tue, 14 Oct 2014 15:03:03 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: From: Cong Wang Date: Tue, 14 Oct 2014 11:59:25 -0700 > On Tue, Oct 14, 2014 at 6:25 AM, Krzysztof Kolasa wrote: >> W dniu 14.10.2014 o 02:09, Cong Wang pisze: >> >>> On Mon, Oct 13, 2014 at 4:59 PM, Cong Wang wrote: >>>> >>>> Probably not related with this bug, but with regarding to the >>>> offending commit, what's the point of the memmove() in tcp_v4_rcv() >>>> since ip_rcv() already clears IPCB()? >>> >>> Oh, ip options are actually saved in ip_rcv_finish()... Hmm, looks scary >>> to play with variable-length array with memmove().... >>> >> On my other old laptop with 32bit kernel next and graphics card Intel 945GM >> just after the revert commit working OK, >> before, after login to gnome shell in some seconds decorations disappear >> >> 32 bit Ubuntu 12.04.5 LTS, gnome shell, kernel source next 14-10-2014 >> >> Can anyone confirm this ? >> > > Sorry, believe it or not, for me it is hard to find a 32bit machine even VM. :) > > Could the attached patch by any chance help? I noticed cookie_v4_check() > still uses IPCB() instead of TCPCB() at TCP layer. Eric, please review.