linux-kernel - [PATCH 6.18 0/2] Fix NUMA sched domain build errors for GNR and CWF

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Message-Id: <cover.1768948644.git.tim.c.chen@linux.intel.com>
Date: Thu,  5 Feb 2026 13:33:32 -0800
From: Tim Chen <tim.c.chen@...ux.intel.com>
To: stable@...r.kernel.org
Cc: Tim Chen <tim.c.chen@...ux.intel.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...nel.org>,
	Juri Lelli <juri.lelli@...hat.com>,
	Dietmar Eggemann <dietmar.eggemann@....com>,
	Ben Segall <bsegall@...gle.com>,
	Mel Gorman <mgorman@...e.de>,
	Valentin Schneider <vschneid@...hat.com>,
	Tim Chen <tim.c.chen@...el.com>,
	Vincent Guittot <vincent.guittot@...aro.org>,
	Len Brown <len.brown@...el.com>,
	linux-kernel@...r.kernel.org,
	Chen Yu <yu.c.chen@...el.com>,
	K Prateek Nayak <kprateek.nayak@....com>,
	"Gautham R . Shenoy" <gautham.shenoy@....com>,
	Zhao Liu <zhao1.liu@...el.com>,
	Vinicius Costa Gomes <vinicius.gomes@...el.com>,
	Arjan Van De Ven <arjan.van.de.ven@...el.com>
Subject: [PATCH 6.18 0/2] 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