From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Ahern Subject: Re: [PATCH net] ipv4: Avoid caching dsts when lookup skipped nh oif check Date: Thu, 20 Apr 2017 09:16:56 -0600 Message-ID: <7204751a-70f9-5803-d5af-06b62530b762@cumulusnetworks.com> References: <1492693132-4708-1-git-send-email-rshearma@brocade.com> <8dcaa797-c566-a9dc-d9a1-99e8d1acfe15@cumulusnetworks.com> <277d8c4b-5a18-cda2-6edc-66837cae6469@brocade.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: Robert Shearman , davem@davemloft.net Return-path: Received: from mail-yb0-f180.google.com ([209.85.213.180]:35233 "EHLO mail-yb0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S969435AbdDTPQ7 (ORCPT ); Thu, 20 Apr 2017 11:16:59 -0400 Received: by mail-yb0-f180.google.com with SMTP id 6so28266072ybq.2 for ; Thu, 20 Apr 2017 08:16:59 -0700 (PDT) In-Reply-To: <277d8c4b-5a18-cda2-6edc-66837cae6469@brocade.com> Sender: netdev-owner@vger.kernel.org List-ID: On 4/20/17 9:05 AM, Robert Shearman wrote: > The key thing I think is the ip rules: > > $ ip rule > 0: from all lookup local > 1000: from all lookup [l3mdev-table] > 32766: from all lookup main > 32767: from all lookup default > > Maybe you have the local rule moved down at startup? yes that would be a problem. With this test the 127.0.0.1 lookup is matching on the wrong table: perf probe fib_table_lookup%return ret=%ax perf record -e fib:*,probe:* -a -- ping -c1 -w1 -I red 127.0.0.1 ... perf script ping 2803 [000] 70559.086446: fib:fib_table_lookup: table 255 oif 31 iif 1 src 0.0.0.0 dst 127.0.0.1 tos 0 scope 0 flags 4 ping 2803 [000] 70559.086451: fib:fib_table_lookup_nh: nexthop dev lo oif 1 src 127.0.0.1 ping 2803 [000] 70559.086453: probe:fib_table_lookup: (ffffffff8146aaaa <- ffffffff81470734) ret=0x0 ping 2803 [000] 70559.086458: fib:fib_table_lookup: table 255 oif 31 iif 1 src 127.0.0.1 dst 127.0.0.1 tos 0 scope 0 flags 4 ping 2803 [000] 70559.086459: fib:fib_table_lookup_nh: nexthop dev lo oif 1 src 127.0.0.1 ping 2803 [000] 70559.086460: probe:fib_table_lookup: (ffffffff8146aaaa <- ffffffff81470734) ret=0x0 ping 2803 [000] 70559.086752: fib:fib_table_lookup: table 255 oif 31 iif 1 src 0.0.0.0 dst 127.0.0.1 tos 0 scope 0 flags 4 ping 2803 [000] 70559.086754: fib:fib_table_lookup_nh: nexthop dev lo oif 1 src 127.0.0.1 ping 2803 [000] 70559.086755: probe:fib_table_lookup: (ffffffff8146aaaa <- ffffffff81470734) ret=0x0 ping 2803 [000] 70559.086768: fib:fib_table_lookup: table 255 oif 31 iif 1 src 127.0.0.1 dst 127.0.0.1 tos 0 scope 0 flags 5 ping 2803 [000] 70559.086769: fib:fib_table_lookup_nh: nexthop dev lo oif 1 src 127.0.0.1 ping 2803 [000] 70559.086770: probe:fib_table_lookup: (ffffffff8146aaaa <- ffffffff81470734) ret=0x0 ping 2803 [000] 70559.086781: fib:fib_table_lookup: table 255 oif 31 iif 1 src 127.0.0.1 dst 127.0.0.1 tos 0 scope 0 flags 4 ping 2803 [000] 70559.086782: fib:fib_table_lookup_nh: nexthop dev lo oif 1 src 127.0.0.1 ping 2803 [000] 70559.086782: probe:fib_table_lookup: (ffffffff8146aaaa <- ffffffff81470734) ret=0x0 ping 2803 [000] 70559.086787: fib:fib_table_lookup: table 255 oif 31 iif 1 src 127.0.0.1 dst 127.0.0.1 tos 0 scope 0 flags 5 ping 2803 [000] 70559.086788: fib:fib_table_lookup_nh: nexthop dev lo oif 1 src 127.0.0.1 ping 2803 [000] 70559.086789: probe:fib_table_lookup: (ffffffff8146aaaa <- ffffffff81470734) ret=0x0 Table 255 is the wrong table. That is the ultimate problem here.