On 10.01.2023 09:49, Wei Chen wrote:
> --- a/xen/arch/arm/include/asm/numa.h
> +++ b/xen/arch/arm/include/asm/numa.h
> @@ -28,6 +28,20 @@ enum dt_numa_status {
> DT_NUMA_OFF,
> };
>
> +/*
> + * In ACPI spec, 0-9 are the reserved values for node distance,
> + * 10 indicates local node distance, 20 indicates remote node
> + * distance. Set node distance map in device tree will follow
> + * the ACPI's definition.
> + */
> +#define NUMA_DISTANCE_UDF_MIN 0
> +#define NUMA_DISTANCE_UDF_MAX 9
> +#define NUMA_LOCAL_DISTANCE 10
> +#define NUMA_REMOTE_DISTANCE 20
In the absence of a caller of numa_set_distance() it is entirely unclear
whether this tying to ACPI used values is actually appropriate.
> --- a/xen/arch/arm/numa.c
> +++ b/xen/arch/arm/numa.c
> @@ -2,7 +2,7 @@
> /*
> * Arm Architecture support layer for NUMA.
> *
> - * Copyright (C) 2021 Arm Ltd
> + * Copyright (C) 2022 Arm Ltd
I don't think it makes sense to change such after the fact. And certainly
not in an unrelated patch.
> @@ -22,6 +22,11 @@
>
> static enum dt_numa_status __read_mostly device_tree_numa;
>
> +static unsigned char __read_mostly
> +node_distance_map[MAX_NUMNODES][MAX_NUMNODES] = {
> + { 0 }
> +};
__ro_after_init?
> @@ -42,3 +47,48 @@ int __init arch_numa_setup(const char *opt)
> {
> return -EINVAL;
> }
> +
> +void __init numa_set_distance(nodeid_t from, nodeid_t to,
> + unsigned int distance)
> +{
> + if ( from >= MAX_NUMNODES || to >= MAX_NUMNODES )
> + {
> + printk(KERN_WARNING
> + "NUMA: invalid nodes: from=%"PRIu8" to=%"PRIu8"
> MAX=%"PRIu8"\n",
> + from, to, MAX_NUMNODES);
> + return;
> + }
> +
> + /* NUMA defines 0xff as an unreachable node and 0-9 are undefined */
> + if ( distance >= NUMA_NO_DISTANCE ||
> + (distance >= NUMA_DISTANCE_UDF_MIN &&
Nit: Indentation.
> + distance <= NUMA_DISTANCE_UDF_MAX) ||
> + (from == to && distance != NUMA_LOCAL_DISTANCE) )
> + {
> + printk(KERN_WARNING
> + "NUMA: invalid distance: from=%"PRIu8" to=%"PRIu8"
> distance=%"PRIu32"\n",
> + from, to, distance);
> + return;
> + }
> +
> + node_distance_map[from][to] = distance;
> +}
> +
> +unsigned char __node_distance(nodeid_t from, nodeid_t to)
> +{
> + /* When NUMA is off, any distance will be treated as remote. */
> + if ( numa_disabled() )
> + return NUMA_REMOTE_DISTANCE;
> +
> + /*
> + * Check whether the nodes are in the matrix range.
> + * When any node is out of range, except from and to nodes are the
> + * same, we treat them as unreachable (return 0xFF)
> + */
> + if ( from >= MAX_NUMNODES || to >= MAX_NUMNODES )
I guess using ARRAY_SIZE() here would be more future-proof.
Jan
