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Updates for NUMA node distance table

Mamatha Inamdar requested to merge mainamdar/centos-stream-9:bz2183473 into main

Description: Updates for NUMA node distance table

Bugzilla: https://bugzilla.redhat.com/2183473

Build Info: https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=52558755

Tested: Verified Brew build test kernel RPMs and confirmed issue is resovled

Signed-off-by: Mamatha Inamdar minamdar@redhat.com

commit b277fc793daf258877b4c0744b52f69d6e6ba22e Author: Aneesh Kumar K.V aneesh.kumar@linux.ibm.com Date: Tue Apr 4 09:44:33 2023 +0530

powerpc/papr_scm: Update the NUMA distance table for the target node

Platform device helper routines won't update the NUMA distance table
while creating a platform device, even if the device is present on a
NUMA node that doesn't have memory or CPU. This is especially true for
pmem devices. If the target node of the pmem device is not online, we
find the nearest online node to the device and associate the pmem device
with that online node. To find the nearest online node, we should have
the numa distance table updated correctly. Update the distance
information during the device probe.

For a papr scm device on NUMA node 3 distance_lookup_table value for
distance_ref_points_depth = 2 before and after fix is below:

Before fix:
  node 3 distance depth 0  - 0
  node 3 distance depth 1  - 0
  node 4 distance depth 0  - 4
  node 4 distance depth 1  - 2
  node 5 distance depth 0  - 5
  node 5 distance depth 1  - 1

After fix
  node 3 distance depth 0  - 3
  node 3 distance depth 1  - 1
  node 4 distance depth 0  - 4
  node 4 distance depth 1  - 2
  node 5 distance depth 0  - 5
  node 5 distance depth 1  - 1

Without the fix, the nearest numa node to the pmem device (NUMA node 3)
will be picked as 4. After the fix, we get the correct numa node which
is 5.

Fixes: da1115fdbd6e ("powerpc/nvdimm: Pick nearby online node if the device node is not online")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230404041433.1781804-1-aneesh.kumar@linux.ibm.com

Signed-off-by: Mamatha Inamdar minamdar@redhat.com

Edited by Mamatha Inamdar

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