From mboxrd@z Thu Jan 1 00:00:00 1970 From: Flavio Leitner Subject: Re: [PATCH net-next 2/2] tcp: improve REUSEADDR/NOREUSEADDR cohabitation Date: Thu, 21 May 2015 17:37:36 -0300 Message-ID: <20150521203736.GI2379@x240.home> References: <1432144742-17786-1-git-send-email-edumazet@google.com> <1432144742-17786-3-git-send-email-edumazet@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "David S. Miller" , netdev , Eric Dumazet , Marcelo Ricardo Leitner To: Eric Dumazet Return-path: Received: from mx1.redhat.com ([209.132.183.28]:38133 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755429AbbEUUhl (ORCPT ); Thu, 21 May 2015 16:37:41 -0400 Content-Disposition: inline In-Reply-To: <1432144742-17786-3-git-send-email-edumazet@google.com> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, May 20, 2015 at 10:59:02AM -0700, Eric Dumazet wrote: > inet_csk_get_port() randomization effort tends to spread > sockets on all the available range (ip_local_port_range) > > This is unfortunate because SO_REUSEADDR sockets have > less requirements than non SO_REUSEADDR ones. > > If an application uses SO_REUSEADDR hint, it is to try to > allow source ports being shared. > > So instead of picking a random port number in ip_local_port_range, > lets try first in first half of the range. > > This gives more chances to use upper half of the range for the > sockets with strong requirements (not using SO_REUSEADDR) > > Note this patch does not add a new sysctl, and only changes > the way we try to pick port number. > > Signed-off-by: Eric Dumazet > Cc: Marcelo Ricardo Leitner > Cc: Flavio Leitner > --- The only downside I can see is that after the patch the applications using the SO_REUSEADDR will reuse ports more often and that could potentially trigger some bug. Looks like a good change to me. Acked-by: Flavio Leitner