From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: [Bug] skb truesize does not update properly in many place Date: Fri, 14 Oct 2011 07:48:33 +0200 Message-ID: <1318571313.2533.77.camel@edumazet-laptop> References: <1318570381-4731-1-git-send-email-roy.qing.li@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: netdev@vger.kernel.org To: roy.qing.li@gmail.com Return-path: Received: from mail-ww0-f44.google.com ([74.125.82.44]:61243 "EHLO mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932566Ab1JNFsm (ORCPT ); Fri, 14 Oct 2011 01:48:42 -0400 Received: by wwf22 with SMTP id 22so2901325wwf.1 for ; Thu, 13 Oct 2011 22:48:41 -0700 (PDT) In-Reply-To: <1318570381-4731-1-git-send-email-roy.qing.li@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: Le vendredi 14 octobre 2011 =C3=A0 13:33 +0800, roy.qing.li@gmail.com a =C3=A9crit : > Hi Eric Dumazet: >=20 > I see you are correcting the wrong skb truesize, I found the > same problem exists in many forms and many places, like: >=20 > After calling skb_fill_page_desc(), what should be updated=20 > to truesize. >=20 > pskb_expand_head(), __pskb_pull_tail()... do not update the > truesize. All this is scheduled, but any help is appreciated. I gave the general idea and patched some drivers, I hope other dev will follow me in this work. I am now focusing in the TCP pruning effect, that we can see with WIFI drivers (and also with drivers using a full PAGE to store a 1500 byte tcp frame), when a single packet loss is happening on a session with large RTT. All this truesize saga started because I was shocked by following "netstat -s" extract on my laptop after few minutes of Internet stuff. 848 packets collapsed in receive queue due to low socket buffer