From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Ricardo Leitner Subject: Re: [PATCH stable 3.2 3.4] ipv4: disable bh while doing route gc Date: Mon, 13 Oct 2014 13:58:31 -0300 Message-ID: <543C04B7.1040005@redhat.com> References: <6c3d6eca5d6a15c01393b010f2116bd169477c5a.1413215324.git.mleitner@redhat.com> <20141013.125225.1129718741415025861.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, hannes@stressinduktion.org To: David Miller Return-path: Received: from mx1.redhat.com ([209.132.183.28]:61479 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754486AbaJMQ7O (ORCPT ); Mon, 13 Oct 2014 12:59:14 -0400 In-Reply-To: <20141013.125225.1129718741415025861.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: On 13-10-2014 13:52, David Miller wrote: > From: Marcelo Ricardo Leitner > Date: Mon, 13 Oct 2014 13:20:38 -0300 > >> Further tests revealed that after moving the garbage collector to a work >> queue and protecting it with a spinlock may leave the system prone to >> soft lockups if bottom half gets very busy. >> >> It was reproced with a set of firewall rules that REJECTed packets. If >> the NIC bottom half handler ends up running on the same CPU that is >> running the garbage collector on a very large cache, the garbage >> collector will not be able to do its job due to the amount of work >> needed for handling the REJECTs and also won't reschedule. >> >> The fix is to disable bottom half during the garbage collecting, as it >> already was in the first place (most calls to it came from softirqs). >> >> Signed-off-by: Marcelo Ricardo Leitner >> Acked-by: Hannes Frederic Sowa > > Please add my: > > Acked-by: David S. Miller > > and submit this directly to -stable, thanks. Will do. Thanks. Marcelo