Re: [PATCH v15 00/10] mm/demotion: Memory tiers and demotion

From: Andrew Morton
Date: Fri Aug 19 2022 - 20:34:43 EST


On Fri, 19 Aug 2022 11:57:18 +0530 Bharata B Rao <bharata@xxxxxxx> wrote:

> > The kernel initialization code makes the decision on which exact tier a memory
> > node should be assigned to based on the requests from the device drivers as well
> > as the memory device hardware information provided by the firmware.
>
> I gave this patchset a quick try on two setups:
>
> 1. With QEMU, when an nvdimm device is bound to dax kmem driver, I can see
> the memory node with pmem getting into a lower tier than DRAM.
>
> 2. In an experimental CXL setup that has DRAM as part of CXL memory, I see that
> CXL memory node falls into the same tier as the regular DRAM tier. This is
> expected for now since there is no code (in low level ACPI driver?) yet to
> map the latency or bandwidth info (when available from firmware) into an
> abstract distance value, and register a memory type for the same. Guess these
> bits can be covered as part of future enhancements.

Should I add your Tested-by:?