From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756259Ab0LHTHk (ORCPT ); Wed, 8 Dec 2010 14:07:40 -0500 Received: from rcsinet10.oracle.com ([148.87.113.121]:19054 "EHLO rcsinet10.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756227Ab0LHTHj (ORCPT ); Wed, 8 Dec 2010 14:07:39 -0500 Message-ID: <4CFFD715.4090900@kernel.org> Date: Wed, 08 Dec 2010 11:05:57 -0800 From: Yinghai Lu User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.15) Gecko/20101026 SUSE/3.0.10 Thunderbird/3.0.10 MIME-Version: 1.0 To: Don Zickus CC: Peter Zijlstra , "Eric W. Biederman" , Vivek Goyal , Ingo Molnar , Jason Wessel , "linux-kernel@vger.kernel.org" , Haren Myneni Subject: Re: perf hw in kexeced kernel broken in tip References: <1291234036.32004.2008.camel@laptop> <20101202052321.GH18100@redhat.com> <1291275270.4023.20.camel@twins> <20101202161502.GL18100@redhat.com> <1291764620.2032.1293.camel@laptop> <20101208140103.GM21786@redhat.com> <1291818005.28378.38.camel@laptop> <1291820356.28378.83.camel@laptop> <4CFFD1C2.1080108@kernel.org> <20101208190158.GA8565@redhat.com> In-Reply-To: <20101208190158.GA8565@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/08/2010 11:01 AM, Don Zickus wrote: > On Wed, Dec 08, 2010 at 10:43:14AM -0800, Yinghai Lu wrote: >> >> can you add sth force_... in command line to take over ownership of perf from BIOS or previous kernel ? >> >> then still can use perf etc after we kexec from RHEL or SLES kernel to later kernel ( from 2.6.37) > > My understand is that you can't because the BIOS is actively using it > behind the scenes of the kernel (well during an SMI). I have a machine > where I tried to force take it but it still stopped triggering interrupts. how about second case: kexec from RHEL 6 stock kernel to upstream kernel ? Thanks Yinghai