Re: [LSF/MM] CXL Boot to Bash - Section 0: ACPI and Linux Resources

From: Yuquan Wang
Date: Thu Mar 27 2025 - 05:36:04 EST


On Thu, Mar 13, 2025 at 04:55:39PM +0000, Jonathan Cameron wrote:
> >
> > Basically, the heuristic is as follows:
> > 1) Add one NUMA node per Proximity Domain described in SRAT
>
> if it contains, memory, CPU or generic initiator.

In the future, srat.c would add one seperate NUMA node for each
Generic Port in SRAT.

System firmware should know the performance characteristics between
CPU/GI to the GP, and the static HMAT should include this coordinate.

Is my understanding right?

Yuquan

>
> > 2) If the SRAT describes all memory described by all CFMWS
> > - do not create nodes for CFMWS
> > 3) If SRAT does not describe all memory described by CFMWS
> > - create a node for that CFMWS
> >
> > Generally speaking, you will see one NUMA node per Host bridge, unless
> > inter-host-bridge interleave is in use (see Section 4 - Interleave).
>
> I just love corners: QoS concerns might mean multiple CFMWS and hence
> multiple nodes per host bridge (feel free to ignore this one - has
> anyone seen this in the wild yet?) Similar mess for properties such
> as persistence, sharing etc.
>
> J
>