Re: [LSF/MM/BPF TOPIC] BoF VM live migration over C XL memory​

Hi David-

On 4/7/23 18:17, David Rientjes wrote:
> On Fri, 7 Apr 2023, James Houghton wrote:
> 
>> On Fri, Apr 7, 2023 at 5:05 PM Dragan Stancevic <[email protected]> wrote:
>>>
>>> Hi folks-
>>>
>>> if it's not too late for the schedule...
>>>
>>> I am starting to tackle VM live migration and hypervisor clustering over
>>> switched CXL memory[1][2], intended for cloud virtualization types of loads.
>>>
>>> I'd be interested in doing a small BoF session with some slides and get
>>> into a discussion/brainstorming with other people that deal with VM/LM
>>> cloud loads. Among other things to discuss would be page migrations over
>>> switched CXL memory, shared in-memory ABI to allow VM hand-off between
>>> hypervisors, etc...
>>>
>>> A few of us discussed some of this under the ZONE_XMEM thread, but I
>>> figured it might be better to start a separate thread.
>>>
>>> If there is interested, thank you.
>>
>> Hi Dragan,
>>
>> Thanks for bringing up this topic. I'd be very interested to be part
>> of this BoF, as I'm also interested in using CXL.mem as a live
>> migration mechanism.
>>
> 
> Thanks for cc'ing me, this would be very interesting to talk about.  Count
> me in!
> 
>>> [1]. High-level overview available at http://nil-migration.org/
>>> [2]. Based on CXL spec 3.0
>>>
> 
> Dragan: I'm curious about the reference to CXL spec 3.0 here, is there
> something specific about 3.0 that this work depends on or should we be
> good-to-go with 2.0 as well?  (Are you referring to 3.0 for security
> extensions?)

I'm referencing 3.0 with regards to switched/shared memory as defined in 
Compute Express Link Specification r3.0, v1.0 8/1/22, Page 51, figure 
1-4, black color scheme circle(3) and bars.


It may be possible to do it with 2.0 but as far as I understand[1] the 
2.0 spec it might be a lot more involved/clunky. I think new 3.0 
features make it easier



[1]. I would love to read 2.0 spec, but I don't have access to 2.0 
spec(only 3.0). But that is my understanding from speaking with some CXL 
folks at last years plumbers when I floated this idea with them.

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