From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeremy Fitzhardinge Subject: Re: Re: [PATCHEs]: support more than 32 VCPUs in guests Date: Mon, 26 Jul 2010 17:37:37 -0700 Message-ID: <4C4E2A51.2080404@goop.org> References: <20100609160920.1445fbbe@mantra.us.oracle.com> <4C102742.3010108@goop.org> <20100609170825.06a67ff9@mantra.us.oracle.com> <4C1036B0.4060905@goop.org> <20100609191332.588a15d1@mantra.us.oracle.com> <4C15F85A.1050804@goop.org> <20100614194926.2f81ed3d@mantra.us.oracle.com> <4C173A2B.2050701@goop.org> <20100615114543.644442a9@mantra.us.oracle.com> <4C4E12EF.6070108@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4C4E12EF.6070108@goop.org> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Mukesh Rathor Cc: "Xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org On 07/26/2010 03:57 PM, Jeremy Fitzhardinge wrote: > On 06/15/2010 11:45 AM, Mukesh Rathor wrote: >> On Tue, 15 Jun 2010 09:30:35 +0100 >> Jeremy Fitzhardinge wrote: >> >>> On 06/15/2010 03:49 AM, Mukesh Rathor wrote: >>>> On Mon, 14 Jun 2010 10:37:30 +0100 >>>> Jeremy Fitzhardinge wrote: >>>> >>>> >>>>> On 06/10/2010 03:13 AM, Mukesh Rathor wrote: >>>>> >>>>>> Well, BUG_ON is only triggered if booting more than 32 VCPUs on a >>>>>> *very old* xen (pre xen 3.1.0). >>>>>> >>>>>> Looking at code closely, we could just set setup_max_cpus to 32 >>>>>> some where in xen function, perhaps even in xen_vcpu_setup(). >>>>>> That way later in smp_init() it would just be ok. >>>>>> >>>>>> >>>>> Yes. >>>>> >>>>> >>>>>> One thing tho, the per cpus areas are already setup at that point, >>>>>> so that would need to be cleaned. BTW, I don't understand why >>>>>> have_vcpu_info_placement is set to 0 in xen_guest_init()? >>>>>> >>>>>> >>>>> xen_guest_init is used by the pvhvm path, and hvm domains don't >>>>> have a notion of vcpu info placement. >>>>> >>>>> >>>>>> What minimum version of xen is required to run pvops kernel? >>>>>> >>>>>> >>>>> In theory it should be back-compatible for all Xen 3, but in >>>>> practice it tweaks lots of bugs in older Xens (particularly >>>>> 32-on-64). I don't know that anyone has definitively established >>>>> an earliest version. I implemented vcpu info placement for use in >>>>> pvops kernels, but it was never my intention that it be an >>>>> absolute requirement. >>>>> >>>>> J >>>>> >>>> Ok, attached patch without BUG_ON. Please feel free to modify >>>> to your liking also. >>>> >>> It looks like you smashed all the tabs into spaces so its hard to see >>> what you've changed in the diff. I'll fix it up and give it a >>> look-over. >>> >>> J >> Sorry, I've tabs turned off because patches I submit to other product I >> work on must be tab free. Anyways, re attached a new one with tabs. > > This doesn't compile with CONFIG_SMP=n because setup_max_cpus doesn't > exist. For now I've just put a couple of #ifdef CONFIG_SMPs in there > to avoid compile errors, but could you look at coming up with a > cleaner solution? Hm, I committed a tidier version. I don't see it getting much better. J