From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759245AbZDQRIv (ORCPT ); Fri, 17 Apr 2009 13:08:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756294AbZDQRIj (ORCPT ); Fri, 17 Apr 2009 13:08:39 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:36194 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755896AbZDQRIh (ORCPT ); Fri, 17 Apr 2009 13:08:37 -0400 Subject: Re: [PATCH] netfilter: per-cpu spin-lock with recursion (v0.8) From: Peter Zijlstra To: Eric Dumazet Cc: Stephen Hemminger , paulmck@linux.vnet.ibm.com, David Miller , kaber@trash.net, torvalds@linux-foundation.org, jeff.chua.linux@gmail.com, paulus@samba.org, mingo@elte.hu, laijs@cn.fujitsu.com, jengelh@medozas.de, r000n@r000n.net, linux-kernel@vger.kernel.org, netfilter-devel@vger.kernel.org, netdev@vger.kernel.org, benh@kernel.crashing.org In-Reply-To: <49E81E63.2090909@cosmosbay.com> References: <20090415170111.6e1ca264@nehalam> <49E72E83.50702@trash.net> <20090416.153354.170676392.davem@davemloft.net> <20090416234955.GL6924@linux.vnet.ibm.com> <20090416165233.5d8bbfb5@nehalam> <49E81B9D.3030807@cosmosbay.com> <49E81E63.2090909@cosmosbay.com> Content-Type: text/plain Date: Fri, 17 Apr 2009 19:08:15 +0200 Message-Id: <1239988095.23397.4823.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.26.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2009-04-17 at 08:14 +0200, Eric Dumazet wrote: > > Also, please dont call this a 'recursive lock', since it is not a general > > recursive lock, as pointed by Linus and Paul. > > > > Second question is about MAX_LOCK_DEPTH > > I meant here the ~256 limit we have on preempt_count, not related to LOCKDEP Very good point, so 256 nested spin_lock() instances will make the kernel unhappy -- since we now (almost?) support up to 4096 cpus, this seems like a no-no.