From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1507EC10F11 for ; Thu, 11 Apr 2019 03:39:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DE7AD2084D for ; Thu, 11 Apr 2019 03:39:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726755AbfDKDjv (ORCPT ); Wed, 10 Apr 2019 23:39:51 -0400 Received: from szxga05-in.huawei.com ([45.249.212.191]:6723 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726624AbfDKDju (ORCPT ); Wed, 10 Apr 2019 23:39:50 -0400 Received: from DGGEMS402-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id 25B7BAA98A231BACCAC7; Thu, 11 Apr 2019 11:39:48 +0800 (CST) Received: from [127.0.0.1] (10.184.189.20) by DGGEMS402-HUB.china.huawei.com (10.3.19.202) with Microsoft SMTP Server id 14.3.408.0; Thu, 11 Apr 2019 11:39:38 +0800 Subject: Re: [PATCH net] net: vrf: remove redundant vrf neigh entry To: David Ahern , Shrijeet Mukherjee , "David S. Miller" , , CC: Mingfangsen References: From: linmiaohe Message-ID: Date: Thu, 11 Apr 2019 11:39:28 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.184.189.20] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019/3/22 23:50, David Ahern wrote: > On 3/22/19 3:10 PM, linmiaohe wrote: >> From: Miaohe Lin >> >> When vrf->rth is created, it wouldn't change in his lifetime.And in >> func vrf_finish_output, we always create a neigh with ip_hdr(skb)->daddr >> as key because rth->rt_gateway is equal to 0. But I think we only need >> one vrf neigh entry because we strip the ethernet header and reset the >> dst_entry in vrf_process_v4_outbound. >> So I set rth->rt_gateway to loopback addr(It's ok to set any other >> valid ip address, just choose one.). And we would only create one vrf >> neigh entry. This helps saving some memory and improving the hitting >> rate of neigh lookup. >> If there is something I misunderstand, it's very nice of you to >> let me know. Thanks a lot. >> >> Signed-off-by: linmiaohe >> --- >> drivers/net/vrf.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c >> index 7c1430ed0244..2b0227fb8f53 100644 >> --- a/drivers/net/vrf.c >> +++ b/drivers/net/vrf.c >> @@ -738,6 +738,7 @@ static int vrf_rtable_create(struct net_device *dev) >> return -ENOMEM; >> >> rth->dst.output = vrf_output; >> + rth->rt_gateway = htonl(INADDR_LOOPBACK); >> >> rcu_assign_pointer(vrf->rth, rth); >> > > Did you investigate how neighbor entries are getting created? The vrf > device has IFF_NOARP set, so neigh entries should not be created. > > . > Hi,David A.,I investigate how neighbor entries are getting created recently. But I can't find where neigh entries is not created when vrf device has IFF_NOARP set. So I add some printk info,and I ping the different host, here is the output: [root@localhost ~]# ip vrf exec vrf1 ping 10.0.0.2 PING 10.0.0.2 (10.0.0.2) 56(84) bytes of data. 64 bytes from 10.0.0.2: icmp_seq=1 ttl=64 time=1.78 ms ^C --- 10.0.0.2 ping statistics --- 1 packets transmitted, 1 received, 0% packet loss, time 0ms rtt min/avg/max/mdev = 1.776/1.776/1.776/0.000 ms [root@localhost ~]# ip vrf exec vrf1 ping 11.0.0.2 PING 11.0.0.2 (11.0.0.2) 56(84) bytes of data. 64 bytes from 11.0.0.2: icmp_seq=1 ttl=64 time=1.59 ms ^C --- 11.0.0.2 ping statistics --- 1 packets transmitted, 1 received, 0% packet loss, time 0ms rtt min/avg/max/mdev = 1.591/1.591/1.591/0.000 ms [root@localhost ~]# ip vrf exec vrf1 ping 11.0.0.3 PING 11.0.0.3 (11.0.0.3) 56(84) bytes of data. ^C --- 11.0.0.3 ping statistics --- 1 packets transmitted, 0 received, 100% packet loss, time 0ms Apr 11 11:01:48 localhost kernel: [ 337.311270] VRF: IFF_NOARP is set Apr 11 11:01:48 localhost kernel: [ 337.311279] VRF: nexthop = 200000a Apr 11 11:01:48 localhost kernel: [ 337.311284] VRF: neigh = (null) after lookup Apr 11 11:01:48 localhost kernel: [ 337.311294] VRF: we create a neigh 000000001e8acd79 Apr 11 11:01:51 localhost kernel: [ 340.026623] VRF: IFF_NOARP is set Apr 11 11:01:51 localhost kernel: [ 340.026627] VRF: nexthop = 200000b Apr 11 11:01:51 localhost kernel: [ 340.026631] VRF: neigh = (null) after lookup Apr 11 11:01:51 localhost kernel: [ 340.026637] VRF: we create a neigh 00000000a0ad96da Apr 11 11:01:56 localhost kernel: [ 345.157529] VRF: IFF_NOARP is set Apr 11 11:01:56 localhost kernel: [ 345.157539] VRF: nexthop = 300000b Apr 11 11:01:56 localhost kernel: [ 345.157544] VRF: neigh = (null) after lookup Apr 11 11:01:56 localhost kernel: [ 345.157556] VRF: we create a neigh 00000000a5167b56 And here is the printk code: if (vrf_dev->flags & IFF_NOARP) { printk(KERN_ERR "VRF: IFF_NOARP is set\n"); rth = rcu_dereference(vrf->rth); nexthop = (__force u32)rt_nexthop(rth, ip_hdr(skb)->daddr); printk(KERN_ERR "VRF: nexthop = %x\n", nexthop); neigh = __ipv4_neigh_lookup_noref(vrf_dev, nexthop); printk(KERN_ERR "VRF: neigh = %p after lookup\n", (void *)neigh); if (unlikely(!neigh)) { neigh = __neigh_create(&arp_tbl, &nexthop, vrf_dev, false); printk(KERN_ERR "VRF: we create a neigh %p\n", (void *)neigh); } } Could you please tell me if I was misunderstanding something again? It's very nice of you if you can figure me out that. Thanks a lot.I am looking forward to your reply.