Date: Fri, 2 Jun 2017 11:29:22 +0100 From: Roger Pau =?iso-8859-1?Q?Monn=E9?= <roger.pau@citrix.com> To: Colin Percival <cperciva@FreeBSD.org> Cc: <src-committers@freebsd.org>, <svn-src-all@freebsd.org>, <svn-src-head@freebsd.org> Subject: Re: svn commit: r319491 - head/sys/dev/xen/netfront Message-ID: <20170602102922.stlu47ceumggu6o7@dhcp-3-128.uk.xensource.com> In-Reply-To: <201706020703.v5273V5A085287@repo.freebsd.org> References: <201706020703.v5273V5A085287@repo.freebsd.org>
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On Fri, Jun 02, 2017 at 07:03:31AM +0000, Colin Percival wrote: > Author: cperciva > Date: Fri Jun 2 07:03:31 2017 > New Revision: 319491 > URL: https://svnweb.freebsd.org/changeset/base/319491 > > Log: > Skip setting the MTU in the netfront driver (xn# devices) if the new MTU > is the same as the old MTU. In particular, on Amazon EC2 "T2" instances > without this change, the network interface is reinitialized every 30 > minutes due to the MTU being (re)set when a new DHCP lease is obtained, > causing packets to be dropped, along with annoying syslog messages about > the link state changing. > > As a side note, the behaviour this commit fixes was responsible for > exposing the locking problems fixed via r318523 and r318631. > > Maintainers of other network interface drivers may wish to consider making > the corresponding change; the handling of SIOCSIFMTU does not seem to > exhibit a great deal of consistency between drivers. Is there any reason this check (ifp->if_mtu == ifr->ifr_mtu) is not done at a higher level for all the drivers? It seems pointless to add this chunk everywhere. Roger.
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