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authorToshi Kani <toshi.kani@hp.com>2015-06-19 17:14:15 -0600
committerDan Williams <dan.j.williams@intel.com>2015-06-26 11:23:38 -0400
commit99759869faf15471cfce251bc138848d8af7d162 (patch)
tree3146c2328644caf70051599e07bed549d1d5d953 /drivers/acpi
parent581388209405902b56d055f644b4dd124a206112 (diff)
downloadleg-kernel-99759869faf15471cfce251bc138848d8af7d162.tar.gz
acpi: Add acpi_map_pxm_to_online_node()
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@hp.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/acpi')
-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);
}