From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net-next] tcp: use TCP_DEFAULT_INIT_RCVWND in tcp_fixup_rcvbuf() Date: Thu, 20 Oct 2011 16:13:56 -0400 (EDT) Message-ID: <20111020.161356.2120784879469409197.davem@davemloft.net> References: <1319138186.2854.5.camel@edumazet-laptop> <20111020.155002.555965434596006787.davem@davemloft.net> <1319140954.2854.12.camel@edumazet-laptop> Mime-Version: 1.0 Content-Type: Text/Plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: netdev@vger.kernel.org To: eric.dumazet@gmail.com Return-path: Received: from shards.monkeyblade.net ([198.137.202.13]:50256 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751082Ab1JTUN7 convert rfc822-to-8bit (ORCPT ); Thu, 20 Oct 2011 16:13:59 -0400 In-Reply-To: <1319140954.2854.12.camel@edumazet-laptop> Sender: netdev-owner@vger.kernel.org List-ID: =46rom: Eric Dumazet Date: Thu, 20 Oct 2011 22:02:34 +0200 > Le jeudi 20 octobre 2011 =E0 15:50 -0400, David Miller a =E9crit : >> From: Eric Dumazet >> Date: Thu, 20 Oct 2011 21:16:26 +0200 >>=20 >> > Since commit 356f039822b (TCP: increase default initial receive >> > window.), we allow sender to send 10 (TCP_DEFAULT_INIT_RCVWND) seg= ments. >> >=20 >> > Change tcp_fixup_rcvbuf() to reflect this change, even if no real = change=20 >> > is expected, since sysctl_tcp_rmem[1] =3D 87380 and this value >> > is bigger than tcp_fixup_rcvbuf() computed rcvmem (~23720) >> >=20 >> > Signed-off-by: Eric Dumazet >> ... >> > + unsigned int mss =3D min_t(unsigned int, tp->advmss, 1460); >>=20 >> I don't understand where this calculation comes from, and even if it >> should be obvious it isn't to me and deserves a mention in the commi= t >> message at a minimum. >=20 > This is the calculation done in commit 356f039822b as well. >=20 > The window is 10*MSS, but no more than 14600 >=20 > On loopback, this matters, because we could end with rcvmem=3D219680 Thanks, please help weak brains like mine by adding this to the commit = message. :-)