From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Fw: [Bug 85091] New: neighbour table overflow is not reported and impacts localhost TCP connectivity Date: Wed, 24 Sep 2014 09:32:16 -0700 Message-ID: <20140924093216.083c77b4@urahara> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit To: netdev@vger.kernel.org Return-path: Received: from mail-pd0-f174.google.com ([209.85.192.174]:41717 "EHLO mail-pd0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751875AbaIXQcZ (ORCPT ); Wed, 24 Sep 2014 12:32:25 -0400 Received: by mail-pd0-f174.google.com with SMTP id g10so8318977pdj.5 for ; Wed, 24 Sep 2014 09:32:25 -0700 (PDT) Received: from urahara (static-50-53-65-80.bvtn.or.frontiernet.net. [50.53.65.80]) by mx.google.com with ESMTPSA id fk11sm15189661pdb.91.2014.09.24.09.32.23 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 24 Sep 2014 09:32:24 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: Begin forwarded message: Date: Wed, 24 Sep 2014 03:44:41 -0700 From: "bugzilla-daemon@bugzilla.kernel.org" To: "stephen@networkplumber.org" Subject: [Bug 85091] New: neighbour table overflow is not reported and impacts localhost TCP connectivity https://bugzilla.kernel.org/show_bug.cgi?id=85091 Bug ID: 85091 Summary: neighbour table overflow is not reported and impacts localhost TCP connectivity Product: Networking Version: 2.5 Kernel Version: 3.8 - 3.17-rc6 Hardware: All OS: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: IPV4 Assignee: shemminger@linux-foundation.org Reporter: aschultz@tpip.net Regression: No With the default gc_thresh values and a busy /16 network attached, the neighbour cache can overflow. No indication is given that this happens and it does impact TCP on localhost. Test setup: * about 16k (simulated IP/MAC's) on one interface * web server behind on second interface * routing between the two * HTTP benchmark from the 16k IP's to the web server * for localhost connectivity verification a netperf instance is run on localhost like so: 'netperf -D 1 -l 600 127.0.0.1' Result: Kernel has to learn the 16k IP/MAC combinations, as soon as gc_thresh3 is hit, netperf stalls, no syslog/kernel message indicates the problem. The only indication are log entries like this: "net_ratelimit: 1464 callbacks suppressed" No other messages are logged. -- You are receiving this mail because: You are the assignee for the bug.