From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751103AbVHLCBU (ORCPT ); Thu, 11 Aug 2005 22:01:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964772AbVHLCBU (ORCPT ); Thu, 11 Aug 2005 22:01:20 -0400 Received: from viper.oldcity.dca.net ([216.158.38.4]:13758 "HELO viper.oldcity.dca.net") by vger.kernel.org with SMTP id S1751051AbVHLCBU (ORCPT ); Thu, 11 Aug 2005 22:01:20 -0400 Subject: Re: [RFC,PATCH] Use RCU to protect tasklist for unicast signals From: Lee Revell To: Ingo Molnar Cc: "Paul E. McKenney" , linux-kernel@vger.kernel.org, dipankar@in.ibm.com, rusty@au1.ibm.com, bmark@us.ibm.com, Thomas Gleixner , Andrew Morton In-Reply-To: <20050811095634.GA19342@elte.hu> References: <20050810171145.GA1945@us.ibm.com> <20050811095634.GA19342@elte.hu> Content-Type: text/plain Date: Thu, 11 Aug 2005 22:00:56 -0400 Message-Id: <1123812057.26878.9.camel@mindpipe> Mime-Version: 1.0 X-Mailer: Evolution 2.3.7 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2005-08-11 at 11:56 +0200, Ingo Molnar wrote: > > For the record, some shortcomings of this patch: > > > > o Needs lots more testing on more architectures. > > > > o Needs performance and stress testing. > > > > o Needs testing in Ingo's PREEMPT_RT environment. > > cool patch! I have integrated it into my PREEMPT_RT tree, and all it > needed to boot was the patch below (doesnt affect the upstream kernel). > Using the raw IRQ flag isnt an issue in the RCU code, all the affected > codepaths are small and deterministic. > Ingo, Doesn't this fix the longest latency we were seeing with PREEMPT_DESKTOP, I don't have a trace handy but the upshot was "signal delivery must remain atomic on !PREEMPT_RT"? Lee