Re: [LSF/MM/BPF TOPIC] DAMON Updates and Plans: Automation of DAMON tuning, tiering, and VM guest scaling

[SeongJae Park <sj@kernel.org>]

On Mon, 29 Jan 2024 12:47:49 -0800 SeongJae Park <sj@kernel.org> wrote:

> Hi all,
> 
> 
> Thanks to the discussions and feedback that we received last year from the
> LSF/MM/BPF 2023's DAMON updates and future plans session[1], DAMON made many
> advances and yet more future plans.  I'd like to again share/discuss the
> followup changes and status we made so far after the last year's session, and
> the future development plans on LSF/MM/BPF 2024.
> 
> A few topics would be shared, including below.
>
[...]
>
> Access/Contiguity-aware Memory Auto-scaling
> -------------------------------------------
> 
> This is a new idea which was not discussed in last year's LSF/MM/BPF.  The main
> purpose is to implement an access-aware, efficient, reliable, and simple to use
> memory over-subscribed VM guest kernels.  Specifically, it will steal guest
> memory based on access patterns in a contiguity-aware manner and report those
> to the host as free to use.  The PSI-based stealing aggressiveness auto-tuning
> may be used.  It will also apply a 'struct page' overhead reduction mechanism
> to the stolen memory.  We're currently thinking about memory hotplugging and
> vmemmap remapping as candidate mechanisms.  For simple usage, the interface
> will be similar to that of virtio-balloon, which is widely adopted.  The first
> version of the more detailed idea[7] has been shared before.
> 
> Because it is still at a pure idea level, not much progress until LSF/MM/BPF is
> expected.  This item would be primarily for the future plans part.  That said,
> at least a second version of the design will be shared before.  Also hopefully
> early proof-of-concepts level implementation or some test results will be
> shared.  Since this is expected to be more for future plans than status update,
> I hope to have more discussions for getting design level concerns and possible
> collaboration chances.

I just posted the RFC IDEA v2 of this with pseudo-code level implementation
example: https://lore.kernel.org/all/20240512193657.79298-1-sj@kernel.org/

Hopefully it will help the idea success or fail faster :)


Thanks,
SJ

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