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ACPI: NUMA: Up-level "map to online node" functionality

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The acpi_map_pxm_to_online_node() helper is used to find the closest
online node to a given proximity domain. This is used to map devices in
a proximity domain with no online memory or cpus to the closest online
node and populate a device's 'numa_node' property. The numa_node
property allows applications to be migrated "close" to a resource.

In preparation for providing a generic facility to optionally map an
address range to its closest online node, or the node the range would
represent were it to be onlined (target_node), up-level the core of
acpi_map_pxm_to_online_node() to a generic mm/numa helper.

Cc: Michal Hocko <mhocko@suse.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Link: https://lore.kernel.org/r/158188324802.894464.13128795207831894206.stgit@dwillia2-desk3.amr.corp.intel.com
This commit is contained in:
Dan Williams 2020-02-16 12:00:48 -08:00
parent bb6d3fb354
commit b2ca916ce3
4 changed files with 61 additions and 42 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

41
drivers/acpi/numa/srat.c
View File

@ -72,47 +72,6 @@ int acpi_map_pxm_to_node(int pxm)
}
EXPORT_SYMBOL(acpi_map_pxm_to_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, min_node;
node = acpi_map_pxm_to_node(pxm);
if (node == NUMA_NO_NODE)
node = 0;
min_node = node;
if (!node_online(node)) {
int min_dist = INT_MAX, dist, n;
for_each_online_node(n) {
dist = node_distance(node, n);
if (dist < min_dist) {
min_dist = dist;
min_node = n;
}
}
}
return min_node;
}
EXPORT_SYMBOL(acpi_map_pxm_to_online_node);
static void __init
acpi_table_print_srat_entry(struct acpi_subtable_header *header)
{

23
include/linux/acpi.h
View File

@ -416,9 +416,30 @@ extern void acpi_osi_setup(char *str);
extern bool acpi_osi_is_win8(void);
#ifdef CONFIG_ACPI_NUMA
int acpi_map_pxm_to_online_node(int pxm);
int acpi_map_pxm_to_node(int pxm);
int acpi_get_node(acpi_handle handle);
/**
* 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.
*/
static inline int acpi_map_pxm_to_online_node(int pxm)
{
int node = acpi_map_pxm_to_node(pxm);
return numa_map_to_online_node(node);
}
#else
static inline int acpi_map_pxm_to_online_node(int pxm)
{

9
include/linux/numa.h
View File

@ -13,4 +13,13 @@
#define NUMA_NO_NODE (-1)
#ifdef CONFIG_NUMA
int numa_map_to_online_node(int node);
#else
static inline int numa_map_to_online_node(int node)
{
return NUMA_NO_NODE;
}
#endif
#endif /* _LINUX_NUMA_H */

30
mm/mempolicy.c
View File

@ -127,6 +127,36 @@ static struct mempolicy default_policy = {
static struct mempolicy preferred_node_policy[MAX_NUMNODES];
/**
* numa_map_to_online_node - Find closest online node
* @nid: Node id to start the search
*
* Lookup the next closest node by distance if @nid is not online.
*/
int numa_map_to_online_node(int node)
{
int min_node;
if (node == NUMA_NO_NODE)
node = 0;
min_node = node;
if (!node_online(node)) {
int min_dist = INT_MAX, dist, n;
for_each_online_node(n) {
dist = node_distance(node, n);
if (dist < min_dist) {
min_dist = dist;
min_node = n;
}
}
}
return min_node;
}
EXPORT_SYMBOL_GPL(numa_map_to_online_node);
struct mempolicy *get_task_policy(struct task_struct *p)
{
struct mempolicy *pol = p->mempolicy;