[PATCH v14 03/10] mm/demotion: Add hotplug callbacks to handle new numa node onlined

From: Aneesh Kumar K.V
Date: Fri Aug 12 2022 - 01:58:19 EST


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@xxxxxxxxxxxxx>
---
include/linux/memory-tiers.h | 1 +
mm/memory-tiers.c | 68 ++++++++++++++++++++++++++++++++++++
2 files changed, 69 insertions(+)

diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h
index 9fdd9572fdf9..cc89876899a6 100644
--- a/include/linux/memory-tiers.h
+++ b/include/linux/memory-tiers.h
@@ -11,6 +11,7 @@
* Smaller abstract distance value imply faster(higher) memory tiers.
*/
#define MEMTIER_ADISTANCE_DRAM (4 * MEMTIER_CHUNK_SIZE)
+#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 f3dc3318d931..05f05395468a 100644
--- a/mm/memory-tiers.c
+++ b/mm/memory-tiers.c
@@ -5,6 +5,7 @@
#include <linux/lockdep.h>
#include <linux/sysfs.h>
#include <linux/kobject.h>
+#include <linux/memory.h>
#include <linux/memory-tiers.h>

struct memory_tier {
@@ -105,6 +106,72 @@ static struct memory_tier *set_node_memory_tier(int node)
return memtier;
}

+static struct memory_tier *__node_get_memory_tier(int node)
+{
+ struct memory_dev_type *memtype;
+
+ memtype = node_memory_types[node];
+ if (memtype && node_isset(node, memtype->nodes))
+ return memtype->memtier;
+ return NULL;
+}
+
+static void destroy_memory_tier(struct memory_tier *memtier)
+{
+ list_del(&memtier->list);
+ kfree(memtier);
+}
+
+static bool clear_node_memory_tier(int node)
+{
+ bool cleared = false;
+ struct memory_tier *memtier;
+
+ memtier = __node_get_memory_tier(node);
+ if (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(&memtier->memory_types))
+ destroy_memory_tier(memtier);
+ }
+ cleared = true;
+ }
+ return cleared;
+}
+
+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:
+ mutex_lock(&memory_tier_lock);
+ clear_node_memory_tier(arg->status_change_nid);
+ mutex_unlock(&memory_tier_lock);
+ break;
+ case MEM_ONLINE:
+ mutex_lock(&memory_tier_lock);
+ set_node_memory_tier(arg->status_change_nid);
+ mutex_unlock(&memory_tier_lock);
+ break;
+ }
+
+ return notifier_from_errno(0);
+}
+
static int __init memory_tier_init(void)
{
int node;
@@ -126,6 +193,7 @@ static int __init memory_tier_init(void)
}
mutex_unlock(&memory_tier_lock);

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