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-rw-r--r--drivers/acpi/numa.c50
1 files changed, 47 insertions, 3 deletions
diff --git a/drivers/acpi/numa.c b/drivers/acpi/numa.c
index 1333cbdc3ea2..acaa3b4ea504 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);
}