From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arkadi Sharshevsky Subject: Re: mlxsw and rtnl lock Date: Tue, 29 Aug 2017 22:16:10 +0300 Message-ID: <32962969-5999-e475-75f1-6ac7e5d76f1b@mellanox.com> References: <20170826170418.GA22324@shredder> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: Jiri Pirko , "netdev@vger.kernel.org" , mlxsw@mellanox.com To: David Ahern , Ido Schimmel Return-path: Received: from mail-eopbgr20053.outbound.protection.outlook.com ([40.107.2.53]:53674 "EHLO EUR02-VE1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751215AbdH2TQS (ORCPT ); Tue, 29 Aug 2017 15:16:18 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On 08/28/2017 09:00 PM, David Ahern wrote: > On 8/26/17 11:04 AM, Ido Schimmel wrote: >> Regarding the silent abort, that's intentional. You can look at the same >> code in v4.9 - when the chain was still blocking - and you'll see that >> we didn't propagate the error even then. This was discussed in the past >> and the conclusion was that user doesn't expect to operation to fail. If >> hardware resources are exceeded, we let the kernel take care of the >> forwarding instead. >> > > In addition to Roopa's comments... The silent abort is not a good user > experience. Right now it's add a network address or route, cross fingers > and hope it does not overflow some limit (nexthop, ecmp, neighbor, > prefix, etc) that triggers the offload abort. > > The mlxsw driver queries for some limits (e.g., max rifs) but I don't > see any query related to current usage, and there is no API to pass any > of that data to user space so user space has no programmatic way to > handle this. I realize you are aware of this limitation. The point is to The first dpipe table that was introduced was the erif table. which gathers L3 statistics. The rifs are actually also fixed size resource, so maybe it is more correct to introduce it as 'resources' and connect it to the erif table. That way you will be able to obtain current usage, and receive notification when it will be drained out. > emphasize the need to resolve this. >