On Tue, 12 Oct 2021 15:56:29 -0300 Jason Gunthorpe [off-list ref] wrote:

quoted

To what other uses will this infrastructure be put?

Because I must ask: if this feature is for one single computer which
presumably has a custom kernel, why add it to mainline Linux?

Well, it certainly isn't just "one single computer". Overall I know of
about, hmm, ~10 *datacenters* worth of installations that are using
similar technology underpinnings.

"Frontier" is the code name for a specific installation but as the
technology is proven out there will be many copies made of that same
approach.

The previous program "Summit" was done with NVIDIA GPUs and PowerPC
CPUs and also included a very similar capability. I think this is a
good sign that this coherently attached accelerator will continue to
be a theme in computing going foward. IIRC this was done using out of
tree kernel patches and NUMA localities.

Specifically with CXL now being standardized and on a path to ubiquity
I think we will see an explosion in deployments of coherently attached
accelerator memory. This is the high end trickling down to wider
usage.

I strongly think many CXL accelerators are going to want to manage
their on-accelerator memory in this way as it makes universal sense to
want to carefully manage memory access locality to optimize for
performance.

Thanks.  Can we please get something like the above into the [0/n]
changelog?  Along with any other high-level info which is relevant?

It's rather important.  "why should I review this", "why should we
merge this", etc.