ccbec01cc9
[ Upstream commit b277fc793daf258877b4c0744b52f69d6e6ba22e ]
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: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.