Fix NUMA sched domain build errors for GNR and CWF

While testing Granite Rapids (GNR) and Clearwater Forest (CWF) systems in SNC-3 mode, we encountered sched domain build errors in dmesg. The scheduler domain code did not expect asymmetric node distances from a local node to multiple nodes in a remote package. As a result, remote nodes ended up being grouped partially with local nodes with asymemtric groupings, and creating too many levels in the NUMA sched domain hierarchy.

To address this, we simplify remote node distances for the purpose of sched domain construction on GNR and CWF. Specifically, we replace the individual distances to nodes within the same remote package with their average distance. This resolves the domain build errors and reduces the number of NUMA sched domain levels.

The actual SLIT NUMA node distances are still preserved separately, in case they are needed when building sched domains. NUMA balancing continues to use the true distances when selecting a closer remote node for a task’s numa_group.

These patches have been merged upstream.

Thanks,
Tim

Tim Chen (2):
sched: Create architecture specific sched domain distances sched/topology: Fix sched domain build error for GNR, CWF in SNC-3
mode

 arch/x86/kernel/smpboot.c |  70 ++++++++++++++++++++++++
 kernel/sched/topology.c   | 108 ++++++++++++++++++++++++++++++--------
 2 files changed, 156 insertions(+), 22 deletions(-)

2.32.0