From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hagen Paul Pfeifer Subject: Re: RFC Hanging clean-up of a namespace Date: Thu, 19 Jan 2012 22:40:53 +0100 Message-ID: <20120119214052.GA12249@hell> References: <20120119192541.GM2262734@jupiter.n2.diac24.net> <20120119.143105.735366189369504929.davem@davemloft.net> <20120119195349.GN2262734@jupiter.n2.diac24.net> <20120119.152752.318442465605898328.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: David Miller , equinox@diac24.net, hans.schillstrom@ericsson.com, netdev@vger.kernel.org To: "Eric W. Biederman" Return-path: Received: from alternativer.internetendpunkt.de ([88.198.24.89]:53635 "EHLO geheimer.internetendpunkt.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752850Ab2ASVlA (ORCPT ); Thu, 19 Jan 2012 16:41:00 -0500 Content-Disposition: inline In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: * Eric W. Biederman | 2012-01-19 13:24:13 [-0800]: >This thread is a fascinating disconnect from reality all of the way >around. > >- inet_twsk_purge already implements throwing out of timewait sockets > when a network namespaces is being cleaned up. So the RFC is nonsense. This is how it is implemented, not how it should be. TIME_WAIT is not the problem, it is there to keep the stack from sending wrong RST messages. Maybe the 2*MSL could be fixed by a more accurate 2*RTT. >- Keeping the timewait sockets at that point we purge them in the code > can achieve nothing. We don't have any userspace processes or network > devices associated with the timewait sockets at the point we get rid > of them. The network namespace exists so long as a userspace process > can find it. The network namespace exit is asynchronous in it's own > workqueue so userspace definitely is not blocked. Another possible solution could be a netns global TIME_WAIT list. But this is a little bit expensive and out of question - but this _is_ a convenient solution. The "5 second reboot" is no argument - it show a discrepance between TCP requirements and the actual situation. Hagen