From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH] net: sock: fix TCP_SKB_MIN_TRUESIZE Date: Wed, 03 Jul 2013 16:52:55 -0700 (PDT) Message-ID: <20130703.165255.2199744750245012601.davem@davemloft.net> References: <1371644355.3252.307.camel@edumazet-glaptop> <20130619.211721.1594350084165223337.davem@davemloft.net> <1372852942.4979.67.camel@edumazet-glaptop> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, dborkman@redhat.com, ncardwell@google.com To: eric.dumazet@gmail.com Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:39430 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932278Ab3GCXw4 (ORCPT ); Wed, 3 Jul 2013 19:52:56 -0400 In-Reply-To: <1372852942.4979.67.camel@edumazet-glaptop> Sender: netdev-owner@vger.kernel.org List-ID: From: Eric Dumazet Date: Wed, 03 Jul 2013 05:02:22 -0700 > From: Eric Dumazet > > commit eea86af6b1e18d ("net: sock: adapt SOCK_MIN_RCVBUF and > SOCK_MIN_SNDBUF") forgot the sk_buff alignment taken into account > in __alloc_skb() : skb->truesize = SKB_TRUESIZE(size); > > While above commit fixed the sender issue, the receiver is still > dropping the second packet (on loopback device), because the receiver > socket can not really hold two skbs : > First packet truesize already is above sk_rcvbuf, so even TCP coalescing > cannot help. > > On a typical 64bit build, each tcp skb truesize is 2304, instead of 2272 > > Signed-off-by: Eric Dumazet Applied.