From b2ca916ce392a9d4cea3489a3efb2b627b839eaf Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Sun, 16 Feb 2020 12:00:48 -0800 Subject: [PATCH] ACPI: NUMA: Up-level "map to online node" functionality 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 Acked-by: Rafael J. Wysocki Reviewed-by: Ingo Molnar Signed-off-by: Dan Williams Link: https://lore.kernel.org/r/158188324802.894464.13128795207831894206.stgit@dwillia2-desk3.amr.corp.intel.com --- drivers/acpi/numa/srat.c | 41 ----------------------------------------- include/linux/acpi.h | 23 ++++++++++++++++++++++- include/linux/numa.h | 9 +++++++++ mm/mempolicy.c | 30 ++++++++++++++++++++++++++++++ 4 files changed, 61 insertions(+), 42 deletions(-) diff --git a/drivers/acpi/numa/srat.c b/drivers/acpi/numa/srat.c index eadbf90e6..47b4969 100644 --- a/drivers/acpi/numa/srat.c +++ b/drivers/acpi/numa/srat.c @@ -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) { diff --git a/include/linux/acpi.h b/include/linux/acpi.h index 0f24d70..3839363 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -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) { diff --git a/include/linux/numa.h b/include/linux/numa.h index 110b0e5..20f4e44 100644 --- a/include/linux/numa.h +++ b/include/linux/numa.h @@ -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 */ diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 977c641..756d6e5 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -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; -- 2.7.4