[PATCH v2 1/6] numa: generalize numa_map_to_online_node()

Yury Norov
2023-08-19T14:12:47Z

The function in fact searches the nearest node for a given one,
based on a N_ONLINE state. This is a common pattern to search
for a nearest node.

This patch converts numa_map_to_online_node() to numa_nearest_node()
so that others won't need to opencode the logic.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
---
include/linux/numa.h | 7 +++++--
mm/mempolicy.c | 18 +++++++++++-------
2 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/include/linux/numa.h b/include/linux/numa.h
index 59df211d051f..fb30a42f0700 100644
--- a/include/linux/numa.h
+++ b/include/linux/numa.h
@@ -25,7 +25,7 @@
#include <asm/sparsemem.h>

/* Generic implementation available */
-int numa_map_to_online_node(int node);
+int numa_nearest_node(int node, unsigned int state);

#ifndef memory_add_physaddr_to_nid
static inline int memory_add_physaddr_to_nid(u64 start)
@@ -44,10 +44,11 @@ static inline int phys_to_target_node(u64 start)
}
#endif
#else /* !CONFIG_NUMA */
-static inline int numa_map_to_online_node(int node)
+static inline int numa_nearest_node(int node, unsigned int state)
{
return NUMA_NO_NODE;
}
+
static inline int memory_add_physaddr_to_nid(u64 start)
{
return 0;
@@ -58,6 +59,8 @@ static inline int phys_to_target_node(u64 start)
}
#endif

+#define numa_map_to_online_node(node) numa_nearest_node(node, N_ONLINE)
+
#ifdef CONFIG_HAVE_ARCH_NODE_DEV_GROUP
extern const struct attribute_group arch_node_dev_group;
#endif
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index c53f8beeb507..0fc9a3b1d765 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -131,22 +131,26 @@ static struct mempolicy default_policy = {
static struct mempolicy preferred_node_policy[MAX_NUMNODES];

/**
- * numa_map_to_online_node - Find closest online node
+ * numa_nearest_node - Find nearest node by state
* @node: Node id to start the search
+ * @state: State to filter the search
*
- * Lookup the next closest node by distance if @nid is not online.
+ * Lookup the closest node by distance if @nid is not in state.
*
- * Return: this @node if it is online, otherwise the closest node by distance
+ * Return: this @node if it is in state, otherwise the closest node by distance
*/
-int numa_map_to_online_node(int node)
+int numa_nearest_node(int node, unsigned int state)
{
int min_dist = INT_MAX, dist, n, min_node;

- if (node == NUMA_NO_NODE || node_online(node))
+ if (state >= NR_NODE_STATES)
+ return -EINVAL;
+
+ if (node == NUMA_NO_NODE || node_state(node, state))
return node;

min_node = node;
- for_each_online_node(n) {
+ for_each_node_state(n, state) {
dist = node_distance(node, n);
if (dist < min_dist) {
min_dist = dist;
@@ -156,7 +160,7 @@ int numa_map_to_online_node(int node)

return min_node;
}
-EXPORT_SYMBOL_GPL(numa_map_to_online_node);
+EXPORT_SYMBOL_GPL(numa_nearest_node);

struct mempolicy *get_task_policy(struct task_struct *p)
{
--
2.39.2