From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758038AbXKKUtj (ORCPT ); Sun, 11 Nov 2007 15:49:39 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757071AbXKKUtb (ORCPT ); Sun, 11 Nov 2007 15:49:31 -0500 Received: from gate.crashing.org ([63.228.1.57]:51598 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753970AbXKKUtb (ORCPT ); Sun, 11 Nov 2007 15:49:31 -0500 Subject: Re: [PATCH, RFC] improved hacks to allow -rt to run kernbench on POWER From: Benjamin Herrenschmidt Reply-To: benh@kernel.crashing.org To: Steven Rostedt Cc: paulmck@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, tony@bakeyournoodle.com, paulus@samba.org, dino@in.ibm.com, tytso@us.ibm.com, dvhltc@us.ibm.com, niv@us.ibm.com, antonb@us.ibm.com In-Reply-To: References: <20071109181028.GA26800@linux.vnet.ibm.com> <1194641524.21340.14.camel@pasglop> <20071109220717.GJ8826@linux.vnet.ibm.com> <1194753541.21340.26.camel@pasglop> Content-Type: text/plain Date: Mon, 12 Nov 2007 07:48:45 +1100 Message-Id: <1194814125.6510.14.camel@pasglop> Mime-Version: 1.0 X-Mailer: Evolution 2.12.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 2007-11-11 at 09:45 -0500, Steven Rostedt wrote: > > Well, I suppose the patch could go in, maybe with some ifdef's > around > > the bits in _switch_to, there's little point in doing that on non-rt > > kernels. > > As Nick Piggin already stated, and I'll even state it for the RT > kernel, > we do not allow preemption in switch_to. So it is safe to remove those > "preempt_disable" bits from the patch Sure, I know that, I'm not talking about that, I'm talking about the added code that flush pending batches & save the batch state, since on non-rt kernel, this is not useful (the batch is only ever active within a spinlocked section, which cannot be preempted on non-rt). Ben.