dcc3423c1d
commit b22a8f7b4bde4e4ab73b64908ffd5d90ecdcdbfd upstream.
John Paul reported a warning about bogus NUMA distance values spurred by
commit:
620a6dc40754 ("sched/topology: Make sched_init_numa() use a set for the deduplicating sort")
In this case, the afflicted machine comes up with a reported 256 possible
nodes, all of which are 0 distance away from one another. This was
previously silently ignored, but is now caught by the aforementioned
commit.
The culprit is ia64's node_possible_map which remains unchanged from its
initialization value of NODE_MASK_ALL. In John's case, the machine
doesn't have any SRAT nor SLIT table, but AIUI the possible map remains
untouched regardless of what ACPI tables end up being parsed. Thus,
!online && possible nodes remain with a bogus distance of 0 (distances \in
[0, 9] are "reserved and have no meaning" as per the ACPI spec).
Follow x86 / drivers/base/arch_numa's example and set the possible map to
the parsed map, which in this case seems to be the online map.
Link: http://lore.kernel.org/r/255d6b5d-194e-eb0e-ecdd-97477a534441@physik.fu-berlin.de
Link: https://lkml.kernel.org/r/20210318130617.896309-1-valentin.schneider@arm.com
Fixes: 620a6dc40754 ("sched/topology: Make sched_init_numa() use a set for the deduplicating sort")
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Reported-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Tested-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Tested-by: Sergei Trofimovich <slyfox@gentoo.org>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Anatoly Pugachev <matorola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: dann frazier <dann.frazier@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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.