From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754384Ab1KNOiy (ORCPT ); Mon, 14 Nov 2011 09:38:54 -0500 Received: from rcsinet15.oracle.com ([148.87.113.117]:25882 "EHLO rcsinet15.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751786Ab1KNOix (ORCPT ); Mon, 14 Nov 2011 09:38:53 -0500 Date: Mon, 14 Nov 2011 09:37:16 -0500 From: Konrad Rzeszutek Wilk To: Len Brown Cc: len.brown@intel.com, jeremy@goop.org, xen-devel@lists.xensource.com, x86@kernel.org, linux-kernel@vger.kernel.org, stable@kernel.org, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, tj@kernel.org, tglx@linutronix.de, trenn@suse.de Subject: Re: [Xen-devel] [PATCH 1/3] cpuidle: If disable_cpuidle() is called, set pm_idle to default_idle. Message-ID: <20111114143716.GB8317@phenom.dumpdata.com> References: <1320786914-10541-1-git-send-email-konrad.wilk@oracle.com> <1320786914-10541-2-git-send-email-konrad.wilk@oracle.com> <20111110040644.GA5434@phenom.dumpdata.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: ucsinet21.oracle.com [156.151.31.93] X-CT-RefId: str=0001.0A090201.4EC127AA.008E,ss=1,re=0.000,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Nov 13, 2011 at 01:00:15AM -0500, Len Brown wrote: > > And just found that there is a BZ for this as well: > > https://bugzilla.redhat.com/show_bug.cgi?id=739499 > > > > And this patch fixes the Linux kernel to boot under Amazon EC2. > > doesn't matter. > > Working around an Amazon EC2 bug in a newly compiled upstream kernel > isn't going to help with any of the kernels that don't include that workaround. Prior to 3.1 we did have a solution for this - we would use the default_idle and not pick and/choose one based on the CPUID flags. It was not really a choice made by "hypervisor wrongly advertises the MWAIT flag", but rather that we want to use the safe_halt, which ends up calling the yield hypercall. That is the optimal solution irregardless of what version of hypervisor is being used. > > Amazon EC2 should not advertise MWAIT support that it does not have, > and all kernels should run on it w/o any workaround. > > Len Brown, Intel Open Source Technology Center > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xensource.com > http://lists.xensource.com/xen-devel