[PATCH v11 3/8] mm/demotion: Add hotplug callbacks to handle new numa node onlined

Aneesh Kumar K.V
2022-07-28T19:05:51Z

If the new NUMA node onlined doesn't have a abstract distance assigned,
the kernel adds the NUMA node to default memory tier.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
include/linux/memory-tiers.h | 1 +
mm/memory-tiers.c | 83 ++++++++++++++++++++++++++++++++++++
2 files changed, 84 insertions(+)

diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h
index b85901c0caba..976f43a5e3be 100644
--- a/include/linux/memory-tiers.h
+++ b/include/linux/memory-tiers.h
@@ -13,6 +13,7 @@
#define MEMTIER_ADISTANCE_DRAM (1 << (MEMTIER_CHUNK_BITS + 2))
/* leave one tier below this slow pmem */
#define MEMTIER_ADISTANCE_PMEM (1 << MEMTIER_CHUNK_BITS)
+#define MEMTIER_HOTPLUG_PRIO 100

#ifdef CONFIG_NUMA
#include <linux/types.h>
diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
index 03e43f3dc942..c9854a394d9b 100644
--- a/mm/memory-tiers.c
+++ b/mm/memory-tiers.c
@@ -3,6 +3,7 @@
#include <linux/nodemask.h>
#include <linux/slab.h>
#include <linux/lockdep.h>
+#include <linux/memory.h>
#include <linux/memory-tiers.h>

struct memory_tier {
@@ -83,6 +84,87 @@ static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memty
return new_memtier;
}

+static struct memory_tier *__node_get_memory_tier(int node)
+{
+ struct memory_dev_type *memtype;
+
+ memtype = node_memory_types[node];
+ if (memtype)
+ return memtype->memtier;
+ return NULL;
+}
+
+static void init_node_memory_tier(int node)
+{
+ struct memory_tier *memtier;
+
+ mutex_lock(&memory_tier_lock);
+
+ memtier = __node_get_memory_tier(node);
+ if (!memtier) {
+ struct memory_dev_type *memtype;
+
+ if (!node_memory_types[node]) {
+ node_memory_types[node] = &default_dram_type;
+ node_set(node, default_dram_type.nodes);
+ }
+ memtype = node_memory_types[node];
+ memtier = find_create_memory_tier(memtype);
+ }
+ mutex_unlock(&memory_tier_lock);
+}
+
+static void destroy_memory_tier(struct memory_tier *memtier)
+{
+ list_del(&memtier->list);
+ kfree(memtier);
+}
+
+static void clear_node_memory_tier(int node)
+{
+ struct memory_tier *current_memtier;
+
+ mutex_lock(&memory_tier_lock);
+ current_memtier = __node_get_memory_tier(node);
+ if (current_memtier) {
+ struct memory_dev_type *memtype;
+
+ memtype = node_memory_types[node];
+ node_clear(node, memtype->nodes);
+ if (nodes_empty(memtype->nodes)) {
+ list_del(&memtype->tier_sibiling);
+ memtype->memtier = NULL;
+ if (list_empty(&current_memtier->memory_types))
+ destroy_memory_tier(current_memtier);
+ }
+ }
+ mutex_unlock(&memory_tier_lock);
+}
+
+static int __meminit memtier_hotplug_callback(struct notifier_block *self,
+ unsigned long action, void *_arg)
+{
+ struct memory_notify *arg = _arg;
+
+ /*
+ * Only update the node migration order when a node is
+ * changing status, like online->offline.
+ */
+ if (arg->status_change_nid < 0)
+ return notifier_from_errno(0);
+
+ switch (action) {
+ case MEM_OFFLINE:
+ clear_node_memory_tier(arg->status_change_nid);
+ break;
+ case MEM_ONLINE:
+ init_node_memory_tier(arg->status_change_nid);
+ break;
+ }
+
+ return notifier_from_errno(0);
+}
+
static int __init memory_tier_init(void)
{
struct memory_tier *memtier;
@@ -97,6 +179,7 @@ static int __init memory_tier_init(void)
__func__, PTR_ERR(memtier));
mutex_unlock(&memory_tier_lock);

+ hotplug_memory_notifier(memtier_hotplug_callback, MEMTIER_HOTPLUG_PRIO);
return 0;
}
subsys_initcall(memory_tier_init);
--
2.37.1