Re: [RFC] Memory tiering kernel alignment

["Christoph Lameter (Ampere)" <cl@linux.com>]

On Thu, 25 Jan 2024, Matthew Wilcox wrote:

> We should reject this technology before it harms our kernel and the
> entire industry.  There's a reason that SGI died.  Nobody wants to buy
> single image machines the size of a data centre.

Some people with big pockets needed these data center sized single image 
machines. SGI died because Intel was not able to support large memory 
(petabytes!) anymore after they neglected to develop the processor that 
they promised contractually to SGI and therefore the tech became unusuable 
for the deep pocketed customers.

The Linux kernel worked just fine with petabyte sized address spaces.

There are certainly use cases for large memory pools. They can be created 
and have been improvised using RDMA. Basically shifting memory back and 
forth into the small memory processor spaces that Intel confined us in by 
taking sections of a simulated petabyte sized cross machine "address 
space" that is spread over lots of network nodes.

CXL could perhaps allow us to come up with a better solution.