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authorAlison Schofield <alison.schofield@intel.com>2021-03-10 11:02:33 -0800
committerPeter Zijlstra <peterz@infradead.org>2021-04-15 18:34:20 +0200
commit2c88d45edbb89029c1190bb3b136d2602f057c98 (patch)
treeaf7664a8031310694def54b75d5d85e8242d87f2 /arch/x86/xen
parent99cb64de36d5c9397a664808b92943e35bdce25e (diff)
downloadlinux-2c88d45edbb89029c1190bb3b136d2602f057c98.tar.gz
x86, sched: Treat Intel SNC topology as default, COD as exception
Commit 1340ccfa9a9a ("x86,sched: Allow topologies where NUMA nodes
share an LLC") added a vendor and model specific check to never
call topology_sane() for Intel Skylake Server systems where NUMA
nodes share an LLC.

Intel Ice Lake and Sapphire Rapids CPUs also enumerate an LLC that is
shared by multiple NUMA nodes. The LLC on these CPUs is shared for
off-package data access but private to the NUMA node for on-package
access. Rather than managing a list of allowable SNC topologies, make
this SNC topology the default, and treat Intel's Cluster-On-Die (COD)
topology as the exception.

In SNC mode, Sky Lake, Ice Lake, and Sapphire Rapids servers do not
emit this warning:

sched: CPU #3's llc-sibling CPU #0 is not on the same node! [node: 1 != 0]. Ignoring dependency.

Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Alison Schofield <alison.schofield@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20210310190233.31752-1-alison.schofield@intel.com
Diffstat (limited to 'arch/x86/xen')
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