From: Valentin Schneider valentin.schneider@arm.com
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-berl... 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 --- arch/ia64/kernel/acpi.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
--- a/arch/ia64/kernel/acpi.c +++ b/arch/ia64/kernel/acpi.c @@ -446,7 +446,8 @@ void __init acpi_numa_fixup(void) if (srat_num_cpus == 0) { node_set_online(0); node_cpuid[0].phys_id = hard_smp_processor_id(); - return; + slit_distance(0, 0) = LOCAL_DISTANCE; + goto out; }
/* @@ -489,7 +490,7 @@ void __init acpi_numa_fixup(void) for (j = 0; j < MAX_NUMNODES; j++) slit_distance(i, j) = i == j ? LOCAL_DISTANCE : REMOTE_DISTANCE; - return; + goto out; }
memset(numa_slit, -1, sizeof(numa_slit)); @@ -514,6 +515,8 @@ void __init acpi_numa_fixup(void) printk("\n"); } #endif +out: + node_possible_map = node_online_map; } #endif /* CONFIG_ACPI_NUMA */