From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Paul E. McKenney" Subject: Re: [PATCH RFC] v1 expedited "big hammer" RCU grace periods Date: Thu, 23 Apr 2009 11:29:28 -0700 Message-ID: <20090423182928.GF6877@linux.vnet.ibm.com> References: <20090423052520.GA13036@linux.vnet.ibm.com> <20090423075436.GB22606@elte.hu> <20090423153402.GC6877@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Ingo Molnar , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, netfilter-devel@vger.kernel.org, akpm@linux-foundation.org, davem@davemloft.net, dada1@cosmosbay.com, zbr@ioremap.net, jeff.chua.linux@gmail.com, paulus@samba.org, laijs@cn.fujitsu.com, jengelh@medozas.de, r000n@r000n.net, benh@kernel.crashing.org, mathieu.desnoyers@polymtl.ca To: Linus Torvalds Return-path: Received: from e4.ny.us.ibm.com ([32.97.182.144]:51320 "EHLO e4.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752910AbZDWS3c (ORCPT ); Thu, 23 Apr 2009 14:29:32 -0400 Content-Disposition: inline In-Reply-To: Sender: netfilter-devel-owner@vger.kernel.org List-ID: On Thu, Apr 23, 2009 at 08:47:02AM -0700, Linus Torvalds wrote: > > > On Thu, 23 Apr 2009, Paul E. McKenney wrote: > > > > Hmmm... I need to ask Jeff Chua what HZ he was running with. Because if > > there was some read-side critical section soaking up 30 milliseconds, > > all that hammering will do is slow things down... > > The original bug report comes from simply bootup: > > "I'm loading all the firewall rules during boot-up and this 6 secs > slowness is really not very nice to wait for." > > IOW, the problematic case likely effectively has _nothing_ else going on. > Sure, there might be some parallelism (the bootup scripts are getting > better for that), but hopefully not 6 seconds worth, and not likely any > complex critical sections. Sounds good to me! ;-) Thanx, Paul