On Friday, June 19, 2015 05:14:15 PM Toshi Kani wrote:
> The kernel initializes CPU & memory's NUMA topology from ACPI
> SRAT table. Some other ACPI tables, such as NFIT and DMAR, also
> contain proximity IDs for their device's NUMA topology. This
> information can be used to improve performance of these devices.
>
> This patch introduces acpi_map_pxm_to_online_node(), which is
> similar to acpi_map_pxm_to_node(), but always returns an online
> node. When the mapped node from a given proximity ID is offline,
> it looks up the node distance table and returns the nearest
> online node.
>
> ACPI device drivers, which are called after the NUMA initialization
> has completed in the kernel, can call this interface to obtain their
> device NUMA topology from ACPI tables. Such drivers do not have to
> deal with offline nodes. A node may be offline when a device
> proximity ID is unique, SRAT memory entry does not exist, or NUMA is
> disabled, ex. "numa=off" on x86.
>
> This patch also moves the pxm range check from acpi_get_node() to
> acpi_map_pxm_to_node().
>
> Signed-off-by: Toshi Kani <toshi.kani@xxxxxx>
Better now. :-)
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>>
> ---
> UPDATE: Remove "-" from "on-line" and "off-line".
> ---
> drivers/acpi/numa.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++---
> include/linux/acpi.h | 5 +++++
> 2 files changed, 52 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/acpi/numa.c b/drivers/acpi/numa.c
> index 1333cbdc..acaa3b4 100644
> --- a/drivers/acpi/numa.c
> +++ b/drivers/acpi/numa.c
> @@ -29,6 +29,8 @@
> #include <linux/errno.h>
> #include <linux/acpi.h>
> #include <linux/numa.h>
> +#include <linux/nodemask.h>
> +#include <linux/topology.h>
>
> #define PREFIX "ACPI: "
>
> @@ -70,7 +72,12 @@ static void __acpi_map_pxm_to_node(int pxm, int node)
>
> int acpi_map_pxm_to_node(int pxm)
> {
> - int node = pxm_to_node_map[pxm];
> + int node;
> +
> + if (pxm < 0 || pxm >= MAX_PXM_DOMAINS)
> + return NUMA_NO_NODE;
> +
> + node = pxm_to_node_map[pxm];
>
> if (node == NUMA_NO_NODE) {
> if (nodes_weight(nodes_found_map) >= MAX_NUMNODES)
> @@ -83,6 +90,45 @@ int acpi_map_pxm_to_node(int pxm)
> return node;
> }
>
> +/**
> + * acpi_map_pxm_to_online_node - Map proximity ID to online node
> + * @pxm: ACPI proximity ID
> + *
> + * This is similar to acpi_map_pxm_to_node(), but always returns an online
> + * node. When the mapped node from a given proximity ID is offline, it
> + * looks up the node distance table and returns the nearest online node.
> + *
> + * ACPI device drivers, which are called after the NUMA initialization has
> + * completed in the kernel, can call this interface to obtain their device
> + * NUMA topology from ACPI tables. Such drivers do not have to deal with
> + * offline nodes. A node may be offline when a device proximity ID is
> + * unique, SRAT memory entry does not exist, or NUMA is disabled, ex.
> + * "numa=off" on x86.
> + */
> +int acpi_map_pxm_to_online_node(int pxm)
> +{
> + int node, n, dist, min_dist;
> +
> + node = acpi_map_pxm_to_node(pxm);
> +
> + if (node == NUMA_NO_NODE)
> + node = 0;
> +
> + if (!node_online(node)) {
> + min_dist = INT_MAX;
> + for_each_online_node(n) {
> + dist = node_distance(node, n);
> + if (dist < min_dist) {
> + min_dist = dist;
> + node = n;
> + }
> + }
> + }
> +
> + return node;
> +}
> +EXPORT_SYMBOL(acpi_map_pxm_to_online_node);
> +
> static void __init
> acpi_table_print_srat_entry(struct acpi_subtable_header *header)
> {
> @@ -328,8 +374,6 @@ int acpi_get_node(acpi_handle handle)
> int pxm;
>
> pxm = acpi_get_pxm(handle);
> - if (pxm < 0 || pxm >= MAX_PXM_DOMAINS)
> - return NUMA_NO_NODE;
>
> return acpi_map_pxm_to_node(pxm);
> }
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index e4da5e3..1b3bbb1 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -289,8 +289,13 @@ extern void acpi_dmi_osi_linux(int enable, const struct dmi_system_id *d);
> extern void acpi_osi_setup(char *str);
>
> #ifdef CONFIG_ACPI_NUMA
> +int acpi_map_pxm_to_online_node(int pxm);
> int acpi_get_node(acpi_handle handle);
> #else
> +static inline int acpi_map_pxm_to_online_node(int pxm)
> +{
> + return 0;
> +}
> static inline int acpi_get_node(acpi_handle handle)
> {
> return 0;
> --
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--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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