From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933165Ab3GKOa7 (ORCPT ); Thu, 11 Jul 2013 10:30:59 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:5857 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932911Ab3GKOa0 (ORCPT ); Thu, 11 Jul 2013 10:30:26 -0400 X-Authority-Analysis: v=2.0 cv=Du3UCRD+ c=1 sm=0 a=Sro2XwOs0tJUSHxCKfOySw==:17 a=Drc5e87SC40A:10 a=tbluxUFyrLkA:10 a=5SG0PmZfjMsA:10 a=IkcTkHD0fZMA:10 a=meVymXHHAAAA:8 a=KGjhK52YXX0A:10 a=kkAV0wLU1hcA:10 a=D19gQVrFAAAA:8 a=PTq3U4hPHSjgs63iyFoA:9 a=QEXdDO2ut3YA:10 a=Sro2XwOs0tJUSHxCKfOySw==:117 X-Cloudmark-Score: 0 X-Authenticated-User: X-Originating-IP: 67.255.60.225 Message-ID: <1373553022.17876.11.camel@gandalf.local.home> Subject: Re: [RFC][PATCH RT 6/6] vtime: Convert vtime_seqlock into raw_spinlock_t and seqcount combo From: Steven Rostedt To: Paul Gortmaker Cc: linux-kernel@vger.kernel.org, linux-rt-users , Thomas Gleixner , Carsten Emde , Sebastian Andrzej Siewior , Clark Williams , "Paul E. McKenney" Date: Thu, 11 Jul 2013 10:30:22 -0400 In-Reply-To: <20130710171212.GA13553@windriver.com> References: <20130626192806.107564905@goodmis.org> <20130626193050.529670718@goodmis.org> <20130710171212.GA13553@windriver.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.4.4-3 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2013-07-10 at 13:12 -0400, Paul Gortmaker wrote: > [[RFC][PATCH RT 6/6] vtime: Convert vtime_seqlock into raw_spinlock_t and seqcount combo] On 26/06/2013 (Wed 15:28) Steven Rostedt wrote: > > > The vtime seqlock needs to be taken in true interrupt context on -rt. > > The normal seqlocks are converted to mutexes when PREEMPT_RT_FULL is > > enabled, which will break the vtime code as the calls are done from > > interrupt context. > > > > Convert the vtime seqlock into the raw_spinlock_t and seqcount combo > > that can be done in interrupt context. > > Alternatively, we could revive the raw seqlock patch from Thomas? > > https://lkml.org/lkml/2010/2/17/238 > > Below is a version updating it to 3.8.x-RT. One downside is that > current mainline kernels have raw_seqcount_begin() function, which has > nothing to do with preempt-rt, so the seqcount function namespace can > get confusing unless we rename raw_seqcount_begin to something that > doesn't sound RT-ish. There's a reason that Thomas didn't bring that patch forward, but I don't recall what it was. Thomas? -- Steve