Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934407Ab2HWU5R (ORCPT ); Thu, 23 Aug 2012 16:57:17 -0400 Received: from mail-ob0-f174.google.com ([209.85.214.174]:59755 "EHLO mail-ob0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756921Ab2HWU5O (ORCPT ); Thu, 23 Aug 2012 16:57:14 -0400 Message-ID: <50369925.3050705@lwfinger.net> Date: Thu, 23 Aug 2012 15:57:09 -0500 From: Larry Finger User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20120713 Thunderbird/14.0 MIME-Version: 1.0 To: Eric Dumazet CC: Neal Cardwell , "David S. Miller" , John W Linville , linux-wireless , LKML Subject: Re: Regression associated with commit c8628155ece3 - "tcp: reduce out_of_order memory use" References: <50345B12.1050600@lwfinger.net> <1345612503.5158.566.camel@edumazet-glaptop> <50355021.7000408@lwfinger.net> <1345694593.5904.87.camel@edumazet-glaptop> In-Reply-To: <1345694593.5904.87.camel@edumazet-glaptop> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1085 Lines: 29 On 08/22/2012 11:03 PM, Eric Dumazet wrote: > > Changing the allocation size removes the problem ? thats really strange. > > If you try different sizes in the 9100-30720 range, can you pinpoint the > failure threshold ? The allocation size change did not fix the problem. It turned out that 10 tries from a secure web page were not enough to trigger this intermittent problem that particular test. Based on DaveM's comment that skb->truesize could be wrong, I tried setting truesize after every netdev_alloc_skb() call. Of course, that had no effect. I then found https://lkml.org/lkml/2010/11/19/505I, which clearly states why this need not be done. What skb modifications require that truesize be adjusted? The driver never resets skb->len or skb->data_len for any buffers, other than setting skb->len to zero. Thanks, Larry -- 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/