From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Gunthorpe Subject: Re: [PATCH] IB/ipoib: Change To max_cm_mtu when changing mode to connected Date: Mon, 8 Jun 2015 15:07:51 -0600 Message-ID: <20150608210751.GA13388@obsidianresearch.com> References: <1433673371-5355-1-git-send-email-erezsh@mellanox.com> <20150608164224.GA2499@obsidianresearch.com> <1433797482.90034.2.camel@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1433797482.90034.2.camel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Doug Ledford Cc: Erez Shitrit , linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, ogerlitz-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org, vlad-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org, ELi Cohen List-Id: linux-rdma@vger.kernel.org On Mon, Jun 08, 2015 at 05:04:42PM -0400, Doug Ledford wrote: > On Mon, 2015-06-08 at 10:42 -0600, Jason Gunthorpe wrote: > > On Sun, Jun 07, 2015 at 01:36:11PM +0300, Erez Shitrit wrote: > > > > > > When switching between modes (datagram / connected) change the MTU > > > accordingly. > > > datagram mode up to 4K, connected mode up to (64K - 0x10). > > > > Is this a bug fix (describe the user visible impact)? Should it go to > > -stable? Add a Fixes: line? > > I'm not sure I would call it a bug. Setting the MTU to max > automatically is a policy decision more than anything else. Currently, > you have to enable connected mode, then set the MTU. Both initscripts > and NetworkManager do this for you on Red Hat, so the user sees no > difference here. I can't speak to other OSes. I'm OK with setting > connected mode MTU to max by default once we get the scatter/gather > support for IPoIB added. I was thinking about the other direction, what happens when you turn connected mode off? Jason -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html