From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: [PATCH net] bonding: fix arp monitoring with vlan slaves Date: Fri, 02 Aug 2013 17:03:43 -0700 Message-ID: <1375488223.4457.16.camel@edumazet-glaptop> References: <1375461665-4186-1-git-send-email-nikolay@redhat.com> <20130802.153212.1340051334413929810.davem@davemloft.net> <1375485466.4457.4.camel@edumazet-glaptop> <51FC40E5.6050809@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: David Miller , netdev@vger.kernel.org, andy@greyhouse.net, fubar@us.ibm.com To: Nikolay Aleksandrov Return-path: Received: from mail-pd0-f181.google.com ([209.85.192.181]:49582 "EHLO mail-pd0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752386Ab3HCADo (ORCPT ); Fri, 2 Aug 2013 20:03:44 -0400 Received: by mail-pd0-f181.google.com with SMTP id g10so1198175pdj.12 for ; Fri, 02 Aug 2013 17:03:44 -0700 (PDT) In-Reply-To: <51FC40E5.6050809@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: On Sat, 2013-08-03 at 01:29 +0200, Nikolay Aleksandrov wrote: > I knew it was because of the LLTX, but I was wondering about the possible > reasons for the xmit_lock_owner check. > So basically the arp monitoring (or any dev_trans_start code) won't work > with LLTX devices because they don't get their trans_start updated (not the > txq trans_start nor the dev->trans_start), is this correct ? Nope : LLTX devices are supposed to update their own dev->trans_start I added for these case a special comment as in : drivers/net/ethernet/atheros/atl1e/atl1e_main.c:1883: netdev->trans_start = jiffies; /* NETIF_F_LLTX driver :( */ trans_start is a txq property, and vlan devices have a single txq. Updating the vlandev->trans_start or the vlantxq->trans_start would be a performance killer on MQ ethernet. And frankly, as this trans_start is really seldom queried, it makes no sense to set it on fast path on the vlan device, if its properly done on the real device anyway. > But what if the txqs get bound to a particular CPU, then the txq > trans_start is okay to be updated I suppose. Not sure what you are saying. vlan xmit can be called from any cpus.