Re: [PATCH v8 03/13] x86: maintain COS to CBM mapping for each socket

From: Chao Peng <chao.p.peng@linux.intel.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: wei.liu2@citrix.com, Ian.Campbell@citrix.com,
	stefano.stabellini@eu.citrix.com, andrew.cooper3@citrix.com,
	dario.faggioli@citrix.com, Ian.Jackson@eu.citrix.com,
	xen-devel@lists.xen.org, will.auld@intel.com, keir@xen.org,
	dgdegra@tycho.nsa.gov
Subject: Re: [PATCH v8 03/13] x86: maintain COS to CBM mapping for each socket
Date: Mon, 1 Jun 2015 16:56:21 +0800	[thread overview]
Message-ID: <20150601085621.GB3773@pengc-linux.bj.intel.com> (raw)
In-Reply-To: <556C359F020000780007F8DF@mail.emea.novell.com>

On Mon, Jun 01, 2015 at 09:36:15AM +0100, Jan Beulich wrote:
> >>> On 01.06.15 at 10:05, <chao.p.peng@linux.intel.com> wrote:
> > 2)  Unfeasible to allocate memory first and do initialization later in
> > cpu hotplug notifications. My former approach is performing both the
> > allocation and initialization in the CPU_STARTING, which is not a good
> > idea indicated by Jan.
> 
> Considering
> 
>          info->cos_max = min(opt_cos_max, edx & 0xffff);
> 
> I don't see why you couldn't do an allocation using opt_cos_max
> in CPU_UP_PREPARE, potentially not using all of the slots later
> on.

If memory waste is not a problem (especially in most cases opt_cos_max is
its default 255), then this would be a solution.

As you have suggested this, then I think I can go on this path and still
have asymmetry systems been supported.

Thanks,
Chao