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Date: Wed, 5 Dec 2018 18:27:10 -0500
From: Jerome Glisse <jglisse@redhat.com>
Subject: Re: [RFC PATCH 02/14] mm/hms: heterogenenous memory system (HMS)
 documentation
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To: Logan Gunthorpe <logang@deltatee.com>
Cc: Dan Williams <dan.j.williams@intel.com>, Andi Kleen <ak@linux.intel.com>, Linux MM <linux-mm@kvack.org>, Andrew Morton <akpm@linux-foundation.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, "Rafael J. Wysocki" <rafael@kernel.org>, Dave Hansen <dave.hansen@intel.com>, Haggai Eran <haggaie@mellanox.com>, balbirs@au1.ibm.com, "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>, Benjamin Herrenschmidt <benh@kernel.crashing.org>, "Kuehling, Felix" <felix.kuehling@amd.com>, Philip.Yang@amd.com, "Koenig, Christian" <christian.koenig@amd.com>, "Blinzer, Paul" <Paul.Blinzer@amd.com>, John Hubbard <jhubbard@nvidia.com>, rcampbell@nvidia.com

On Wed, Dec 05, 2018 at 04:23:42PM -0700, Logan Gunthorpe wrote:
> 
> 
> On 2018-12-05 4:20 p.m., Jerome Glisse wrote:
> > And my proposal is under /sys/bus and have symlink to all existing
> > device it agregate in there.
> 
> That's so not the point. Use the existing buses don't invent some
> virtual tree. I don't know how many times I have to say this or in how
> many ways. I'm not responding anymore.

And how do i express interaction with different buses because i just
do not see how to do that in the existing scheme. It would be like
teaching to each bus about all the other bus versus having each bus
register itself under a common framework and have all the interaction
between bus mediated through that common framework avoiding code
duplication accross buses.

> 
> > So you agree with my proposal ? A sysfs directory in which all the
> > bus and how they are connected to each other and what is connected
> > to each of them (device, CPU, memory).
> 
> I'm fine with the motivation. What I'm arguing against is the
> implementation and the fact you have to create a whole grand new
> userspace API and hierarchy to accomplish it.
> 
> Logan