+ mmmemory_hotplug-implement-numa-node-notifier.patch added to mm-new branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm,memory_hotplug: implement numa node notifier
has been added to the -mm mm-new branch.  Its filename is
     mmmemory_hotplug-implement-numa-node-notifier.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mmmemory_hotplug-implement-numa-node-notifier.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days

------------------------------------------------------
From: Oscar Salvador <osalvador@suse.de>
Subject: mm,memory_hotplug: implement numa node notifier
Date: Tue, 3 Jun 2025 13:08:49 +0200

There are at least six consumers of hotplug_memory_notifier that what they
really are interested in is whether any numa node changed its state, e.g:
going from being memory aware to becoming memoryless and vice versa.

Implement a specific notifier for numa nodes when their state gets
changed, and have those consumers that only care about numa node state
changes use it.

Link: https://lkml.kernel.org/r/20250603110850.192912-3-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Harry Yoo <harry.yoo@oracle.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/acpi/numa/hmat.c  |    6 -
 drivers/base/node.c       |   21 ++++
 drivers/cxl/core/region.c |   14 +--
 drivers/cxl/cxl.h         |    4 
 include/linux/memory.h    |   38 ++++++++
 kernel/cgroup/cpuset.c    |    2 
 mm/memory-tiers.c         |    8 -
 mm/memory_hotplug.c       |  161 +++++++++++++++---------------------
 mm/mempolicy.c            |    8 -
 mm/slub.c                 |   13 +-
 10 files changed, 155 insertions(+), 120 deletions(-)

--- a/drivers/acpi/numa/hmat.c~mmmemory_hotplug-implement-numa-node-notifier
+++ a/drivers/acpi/numa/hmat.c
@@ -962,10 +962,10 @@ static int hmat_callback(struct notifier
 			 unsigned long action, void *arg)
 {
 	struct memory_target *target;
-	struct memory_notify *mnb = arg;
+	struct node_notify *mnb = arg;
 	int pxm, nid = mnb->status_change_nid;
 
-	if (nid == NUMA_NO_NODE || action != MEM_ONLINE)
+	if (nid == NUMA_NO_NODE || action != NODE_BECAME_MEM_AWARE)
 		return NOTIFY_OK;
 
 	pxm = node_to_pxm(nid);
@@ -1118,7 +1118,7 @@ static __init int hmat_init(void)
 	hmat_register_targets();
 
 	/* Keep the table and structures if the notifier may use them */
-	if (hotplug_memory_notifier(hmat_callback, HMAT_CALLBACK_PRI))
+	if (hotplug_node_notifier(hmat_callback, HMAT_CALLBACK_PRI))
 		goto out_put;
 
 	if (!hmat_set_default_dram_perf())
--- a/drivers/base/node.c~mmmemory_hotplug-implement-numa-node-notifier
+++ a/drivers/base/node.c
@@ -111,6 +111,27 @@ static const struct attribute_group *nod
 	NULL,
 };
 
+#ifdef CONFIG_MEMORY_HOTPLUG
+static BLOCKING_NOTIFIER_HEAD(node_chain);
+
+int register_node_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(&node_chain, nb);
+}
+EXPORT_SYMBOL(register_node_notifier);
+
+void unregister_node_notifier(struct notifier_block *nb)
+{
+	blocking_notifier_chain_unregister(&node_chain, nb);
+}
+EXPORT_SYMBOL(unregister_node_notifier);
+
+int node_notify(unsigned long val, void *v)
+{
+	return blocking_notifier_call_chain(&node_chain, val, v);
+}
+#endif
+
 static void node_remove_accesses(struct node *node)
 {
 	struct node_access_nodes *c, *cnext;
--- a/drivers/cxl/core/region.c~mmmemory_hotplug-implement-numa-node-notifier
+++ a/drivers/cxl/core/region.c
@@ -2432,12 +2432,12 @@ static int cxl_region_perf_attrs_callbac
 					  unsigned long action, void *arg)
 {
 	struct cxl_region *cxlr = container_of(nb, struct cxl_region,
-					       memory_notifier);
-	struct memory_notify *mnb = arg;
+					       node_notifier);
+	struct node_notify *mnb = arg;
 	int nid = mnb->status_change_nid;
 	int region_nid;
 
-	if (nid == NUMA_NO_NODE || action != MEM_ONLINE)
+	if (nid == NUMA_NO_NODE || action != NODE_BECAME_MEM_AWARE)
 		return NOTIFY_DONE;
 
 	/*
@@ -3484,7 +3484,7 @@ static void shutdown_notifiers(void *_cx
 {
 	struct cxl_region *cxlr = _cxlr;
 
-	unregister_memory_notifier(&cxlr->memory_notifier);
+	unregister_node_notifier(&cxlr->node_notifier);
 	unregister_mt_adistance_algorithm(&cxlr->adist_notifier);
 }
 
@@ -3523,9 +3523,9 @@ out:
 	if (rc)
 		return rc;
 
-	cxlr->memory_notifier.notifier_call = cxl_region_perf_attrs_callback;
-	cxlr->memory_notifier.priority = CXL_CALLBACK_PRI;
-	register_memory_notifier(&cxlr->memory_notifier);
+	cxlr->node_notifier.notifier_call = cxl_region_perf_attrs_callback;
+	cxlr->node_notifier.priority = CXL_CALLBACK_PRI;
+	register_node_notifier(&cxlr->node_notifier);
 
 	cxlr->adist_notifier.notifier_call = cxl_region_calculate_adistance;
 	cxlr->adist_notifier.priority = 100;
--- a/drivers/cxl/cxl.h~mmmemory_hotplug-implement-numa-node-notifier
+++ a/drivers/cxl/cxl.h
@@ -513,7 +513,7 @@ enum cxl_partition_mode {
  * @flags: Region state flags
  * @params: active + config params for the region
  * @coord: QoS access coordinates for the region
- * @memory_notifier: notifier for setting the access coordinates to node
+ * @node_notifier: notifier for setting the access coordinates to node
  * @adist_notifier: notifier for calculating the abstract distance of node
  */
 struct cxl_region {
@@ -526,7 +526,7 @@ struct cxl_region {
 	unsigned long flags;
 	struct cxl_region_params params;
 	struct access_coordinate coord[ACCESS_COORDINATE_MAX];
-	struct notifier_block memory_notifier;
+	struct notifier_block node_notifier;
 	struct notifier_block adist_notifier;
 };
 
--- a/include/linux/memory.h~mmmemory_hotplug-implement-numa-node-notifier
+++ a/include/linux/memory.h
@@ -99,6 +99,14 @@ int set_memory_block_size_order(unsigned
 #define	MEM_PREPARE_ONLINE	(1<<6)
 #define	MEM_FINISH_OFFLINE	(1<<7)
 
+/* These states are used for numa node notifiers */
+#define NODE_BECOMING_MEM_AWARE		(1<<0)
+#define NODE_BECAME_MEM_AWARE		(1<<1)
+#define NODE_BECOMING_MEMORYLESS	(1<<2)
+#define NODE_BECAME_MEMORYLESS		(1<<3)
+#define NODE_CANCEL_MEM_AWARE		(1<<4)
+#define NODE_CANCEL_MEMORYLESS		(1<<5)
+
 struct memory_notify {
 	/*
 	 * The altmap_start_pfn and altmap_nr_pages fields are designated for
@@ -109,7 +117,10 @@ struct memory_notify {
 	unsigned long altmap_nr_pages;
 	unsigned long start_pfn;
 	unsigned long nr_pages;
-	int status_change_nid_normal;
+	int status_change_nid;
+};
+
+struct node_notify {
 	int status_change_nid;
 };
 
@@ -157,15 +168,34 @@ static inline unsigned long memory_block
 {
 	return 0;
 }
+
+static inline int register_node_notifier(struct notifier_block *nb)
+{
+	return 0;
+}
+static inline void unregister_node_notifier(struct notifier_block *nb)
+{
+}
+static inline int node_notify(unsigned long val, void *v)
+{
+	return 0;
+}
+static inline int hotplug_node_notifier(notifier_fn_t fn, int pri)
+{
+	return 0;
+}
 #else /* CONFIG_MEMORY_HOTPLUG */
 extern int register_memory_notifier(struct notifier_block *nb);
+extern int register_node_notifier(struct notifier_block *nb);
 extern void unregister_memory_notifier(struct notifier_block *nb);
+extern void unregister_node_notifier(struct notifier_block *nb);
 int create_memory_block_devices(unsigned long start, unsigned long size,
 				struct vmem_altmap *altmap,
 				struct memory_group *group);
 void remove_memory_block_devices(unsigned long start, unsigned long size);
 extern void memory_dev_init(void);
 extern int memory_notify(unsigned long val, void *v);
+extern int node_notify(unsigned long val, void *v);
 extern struct memory_block *find_memory_block(unsigned long section_nr);
 typedef int (*walk_memory_blocks_func_t)(struct memory_block *, void *);
 extern int walk_memory_blocks(unsigned long start, unsigned long size,
@@ -185,6 +215,12 @@ int walk_dynamic_memory_groups(int nid,
 	register_memory_notifier(&fn##_mem_nb);			\
 })
 
+#define hotplug_node_notifier(fn, pri) ({		\
+	static __meminitdata struct notifier_block fn##_node_nb =\
+		{ .notifier_call = fn, .priority = pri };\
+	register_node_notifier(&fn##_node_nb);			\
+})
+
 #ifdef CONFIG_NUMA
 void memory_block_add_nid(struct memory_block *mem, int nid,
 			  enum meminit_context context);
--- a/kernel/cgroup/cpuset.c~mmmemory_hotplug-implement-numa-node-notifier
+++ a/kernel/cgroup/cpuset.c
@@ -4051,7 +4051,7 @@ void __init cpuset_init_smp(void)
 	cpumask_copy(top_cpuset.effective_cpus, cpu_active_mask);
 	top_cpuset.effective_mems = node_states[N_MEMORY];
 
-	hotplug_memory_notifier(cpuset_track_online_nodes, CPUSET_CALLBACK_PRI);
+	hotplug_node_notifier(cpuset_track_online_nodes, CPUSET_CALLBACK_PRI);
 
 	cpuset_migrate_mm_wq = alloc_ordered_workqueue("cpuset_migrate_mm", 0);
 	BUG_ON(!cpuset_migrate_mm_wq);
--- a/mm/memory_hotplug.c~mmmemory_hotplug-implement-numa-node-notifier
+++ a/mm/memory_hotplug.c
@@ -699,30 +699,6 @@ static void online_pages_range(unsigned
 	online_mem_sections(start_pfn, end_pfn);
 }
 
-/* check which state of node_states will be changed when online memory */
-static void node_states_check_changes_online(unsigned long nr_pages,
-	struct zone *zone, struct memory_notify *arg)
-{
-	int nid = zone_to_nid(zone);
-
-	arg->status_change_nid = NUMA_NO_NODE;
-	arg->status_change_nid_normal = NUMA_NO_NODE;
-
-	if (!node_state(nid, N_MEMORY))
-		arg->status_change_nid = nid;
-	if (zone_idx(zone) <= ZONE_NORMAL && !node_state(nid, N_NORMAL_MEMORY))
-		arg->status_change_nid_normal = nid;
-}
-
-static void node_states_set_node(int node, struct memory_notify *arg)
-{
-	if (arg->status_change_nid_normal >= 0)
-		node_set_state(node, N_NORMAL_MEMORY);
-
-	if (arg->status_change_nid >= 0)
-		node_set_state(node, N_MEMORY);
-}
-
 static void __meminit resize_zone_range(struct zone *zone, unsigned long start_pfn,
 		unsigned long nr_pages)
 {
@@ -1177,7 +1153,9 @@ int online_pages(unsigned long pfn, unsi
 	int need_zonelists_rebuild = 0;
 	const int nid = zone_to_nid(zone);
 	int ret;
-	struct memory_notify arg;
+	struct memory_notify mem_arg;
+	struct node_notify node_arg;
+	bool cancel_mem_notifier_on_err = false, cancel_node_notifier_on_err = false;
 
 	/*
 	 * {on,off}lining is constrained to full memory sections (or more
@@ -1194,11 +1172,22 @@ int online_pages(unsigned long pfn, unsi
 	/* associate pfn range with the zone */
 	move_pfn_range_to_zone(zone, pfn, nr_pages, NULL, MIGRATE_ISOLATE);
 
-	arg.start_pfn = pfn;
-	arg.nr_pages = nr_pages;
-	node_states_check_changes_online(nr_pages, zone, &arg);
+	node_arg.status_change_nid = NUMA_NO_NODE;
+	if (!node_state(nid, N_MEMORY)) {
+		/* Node is becoming memory aware. Notify consumers */
+		cancel_node_notifier_on_err = true;
+		node_arg.status_change_nid = nid;
+		ret = node_notify(NODE_BECOMING_MEM_AWARE, &node_arg);
+		ret = notifier_to_errno(ret);
+		if (ret)
+			goto failed_addition;
+	}
 
-	ret = memory_notify(MEM_GOING_ONLINE, &arg);
+	cancel_mem_notifier_on_err = true;
+	mem_arg.start_pfn = pfn;
+	mem_arg.nr_pages = nr_pages;
+	mem_arg.status_change_nid = node_arg.status_change_nid;
+	ret = memory_notify(MEM_GOING_ONLINE, &mem_arg);
 	ret = notifier_to_errno(ret);
 	if (ret)
 		goto failed_addition;
@@ -1224,7 +1213,8 @@ int online_pages(unsigned long pfn, unsi
 	online_pages_range(pfn, nr_pages);
 	adjust_present_page_count(pfn_to_page(pfn), group, nr_pages);
 
-	node_states_set_node(nid, &arg);
+	if (node_arg.status_change_nid >= 0)
+		node_set_state(nid, N_MEMORY);
 	if (need_zonelists_rebuild)
 		build_all_zonelists(NULL);
 
@@ -1245,16 +1235,26 @@ int online_pages(unsigned long pfn, unsi
 	kswapd_run(nid);
 	kcompactd_run(nid);
 
+	if (node_arg.status_change_nid >= 0)
+		/*
+		 * Node went from memoryless to having memory. Notify interested
+		 * consumers
+		 */
+		node_notify(NODE_BECAME_MEM_AWARE, &node_arg);
+
 	writeback_set_ratelimit();
 
-	memory_notify(MEM_ONLINE, &arg);
+	memory_notify(MEM_ONLINE, &mem_arg);
 	return 0;
 
 failed_addition:
 	pr_debug("online_pages [mem %#010llx-%#010llx] failed\n",
 		 (unsigned long long) pfn << PAGE_SHIFT,
 		 (((unsigned long long) pfn + nr_pages) << PAGE_SHIFT) - 1);
-	memory_notify(MEM_CANCEL_ONLINE, &arg);
+	if (cancel_mem_notifier_on_err)
+		memory_notify(MEM_CANCEL_ONLINE, &mem_arg);
+	if (cancel_node_notifier_on_err)
+		node_notify(NODE_CANCEL_MEM_AWARE, &node_arg);
 	remove_pfn_range_from_zone(zone, pfn, nr_pages);
 	return ret;
 }
@@ -1886,54 +1886,6 @@ static int __init cmdline_parse_movable_
 }
 early_param("movable_node", cmdline_parse_movable_node);
 
-/* check which state of node_states will be changed when offline memory */
-static void node_states_check_changes_offline(unsigned long nr_pages,
-		struct zone *zone, struct memory_notify *arg)
-{
-	struct pglist_data *pgdat = zone->zone_pgdat;
-	unsigned long present_pages = 0;
-	enum zone_type zt;
-
-	arg->status_change_nid = NUMA_NO_NODE;
-	arg->status_change_nid_normal = NUMA_NO_NODE;
-
-	/*
-	 * Check whether node_states[N_NORMAL_MEMORY] will be changed.
-	 * If the memory to be offline is within the range
-	 * [0..ZONE_NORMAL], and it is the last present memory there,
-	 * the zones in that range will become empty after the offlining,
-	 * thus we can determine that we need to clear the node from
-	 * node_states[N_NORMAL_MEMORY].
-	 */
-	for (zt = 0; zt <= ZONE_NORMAL; zt++)
-		present_pages += pgdat->node_zones[zt].present_pages;
-	if (zone_idx(zone) <= ZONE_NORMAL && nr_pages >= present_pages)
-		arg->status_change_nid_normal = zone_to_nid(zone);
-
-	/*
-	 * We have accounted the pages from [0..ZONE_NORMAL); ZONE_HIGHMEM
-	 * does not apply as we don't support 32bit.
-	 * Here we count the possible pages from ZONE_MOVABLE.
-	 * If after having accounted all the pages, we see that the nr_pages
-	 * to be offlined is over or equal to the accounted pages,
-	 * we know that the node will become empty, and so, we can clear
-	 * it for N_MEMORY as well.
-	 */
-	present_pages += pgdat->node_zones[ZONE_MOVABLE].present_pages;
-
-	if (nr_pages >= present_pages)
-		arg->status_change_nid = zone_to_nid(zone);
-}
-
-static void node_states_clear_node(int node, struct memory_notify *arg)
-{
-	if (arg->status_change_nid_normal >= 0)
-		node_clear_state(node, N_NORMAL_MEMORY);
-
-	if (arg->status_change_nid >= 0)
-		node_clear_state(node, N_MEMORY);
-}
-
 static int count_system_ram_pages_cb(unsigned long start_pfn,
 				     unsigned long nr_pages, void *data)
 {
@@ -1950,10 +1902,14 @@ int offline_pages(unsigned long start_pf
 			struct zone *zone, struct memory_group *group)
 {
 	const unsigned long end_pfn = start_pfn + nr_pages;
-	unsigned long pfn, managed_pages, system_ram_pages = 0;
+	unsigned long pfn, managed_pages, system_ram_pages = 0, present_pages = 0;
 	const int node = zone_to_nid(zone);
+	struct pglist_data *pgdat = zone->zone_pgdat;
 	unsigned long flags;
-	struct memory_notify arg;
+	struct memory_notify mem_arg;
+	struct node_notify node_arg;
+	bool cancel_mem_notifier_on_err = false, cancel_node_notifier_on_err = false;
+	enum zone_type zt;
 	char *reason;
 	int ret;
 
@@ -2012,11 +1968,30 @@ int offline_pages(unsigned long start_pf
 		goto failed_removal_pcplists_disabled;
 	}
 
-	arg.start_pfn = start_pfn;
-	arg.nr_pages = nr_pages;
-	node_states_check_changes_offline(nr_pages, zone, &arg);
+	/*
+	 * Here we count the possible pages within the range [0..ZONE_MOVABLE].
+	 * If after having accounted all the pages, we see that the nr_pages to
+	 * be offlined is greater or equal to the accounted pages, we know that the
+	 * node will become empty, and so, we can clear it for N_MEMORY.
+	 */
+	node_arg.status_change_nid = NUMA_NO_NODE;
+	for (zt = 0; zt <= ZONE_MOVABLE; zt++)
+		present_pages += pgdat->node_zones[zt].present_pages;
+	if (nr_pages >= present_pages)
+		node_arg.status_change_nid = node;
+	if (node_arg.status_change_nid >= 0) {
+		cancel_node_notifier_on_err = true;
+		ret = node_notify(NODE_BECOMING_MEMORYLESS, &node_arg);
+		ret = notifier_to_errno(ret);
+		if (ret)
+			goto failed_removal_isolated;
+	}
 
-	ret = memory_notify(MEM_GOING_OFFLINE, &arg);
+	cancel_mem_notifier_on_err = true;
+	mem_arg.start_pfn = start_pfn;
+	mem_arg.nr_pages = nr_pages;
+	mem_arg.status_change_nid = node_arg.status_change_nid;
+	ret = memory_notify(MEM_GOING_OFFLINE, &mem_arg);
 	ret = notifier_to_errno(ret);
 	if (ret) {
 		reason = "notifier failure";
@@ -2096,27 +2071,33 @@ int offline_pages(unsigned long start_pf
 	 * Make sure to mark the node as memory-less before rebuilding the zone
 	 * list. Otherwise this node would still appear in the fallback lists.
 	 */
-	node_states_clear_node(node, &arg);
+	if (node_arg.status_change_nid >= 0)
+		node_clear_state(node, N_MEMORY);
 	if (!populated_zone(zone)) {
 		zone_pcp_reset(zone);
 		build_all_zonelists(NULL);
 	}
 
-	if (arg.status_change_nid >= 0) {
+	if (node_arg.status_change_nid >= 0) {
 		kcompactd_stop(node);
 		kswapd_stop(node);
+		/* Node went memoryless. Notify interested consumers */
+		node_notify(NODE_BECAME_MEMORYLESS, &node_arg);
 	}
 
 	writeback_set_ratelimit();
 
-	memory_notify(MEM_OFFLINE, &arg);
+	memory_notify(MEM_OFFLINE, &mem_arg);
 	remove_pfn_range_from_zone(zone, start_pfn, nr_pages);
 	return 0;
 
 failed_removal_isolated:
 	/* pushback to free area */
 	undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
-	memory_notify(MEM_CANCEL_OFFLINE, &arg);
+	if (cancel_mem_notifier_on_err)
+		memory_notify(MEM_CANCEL_OFFLINE, &mem_arg);
+	if (cancel_node_notifier_on_err)
+		node_notify(NODE_CANCEL_MEMORYLESS, &node_arg);
 failed_removal_pcplists_disabled:
 	lru_cache_enable();
 	zone_pcp_enable(zone);
--- a/mm/memory-tiers.c~mmmemory_hotplug-implement-numa-node-notifier
+++ a/mm/memory-tiers.c
@@ -872,7 +872,7 @@ static int __meminit memtier_hotplug_cal
 					      unsigned long action, void *_arg)
 {
 	struct memory_tier *memtier;
-	struct memory_notify *arg = _arg;
+	struct node_notify *arg = _arg;
 
 	/*
 	 * Only update the node migration order when a node is
@@ -882,13 +882,13 @@ static int __meminit memtier_hotplug_cal
 		return notifier_from_errno(0);
 
 	switch (action) {
-	case MEM_OFFLINE:
+	case NODE_BECAME_MEMORYLESS:
 		mutex_lock(&memory_tier_lock);
 		if (clear_node_memory_tier(arg->status_change_nid))
 			establish_demotion_targets();
 		mutex_unlock(&memory_tier_lock);
 		break;
-	case MEM_ONLINE:
+	case NODE_BECAME_MEM_AWARE:
 		mutex_lock(&memory_tier_lock);
 		memtier = set_node_memory_tier(arg->status_change_nid);
 		if (!IS_ERR(memtier))
@@ -929,7 +929,7 @@ static int __init memory_tier_init(void)
 	nodes_and(default_dram_nodes, node_states[N_MEMORY],
 		  node_states[N_CPU]);
 
-	hotplug_memory_notifier(memtier_hotplug_callback, MEMTIER_HOTPLUG_PRI);
+	hotplug_node_notifier(memtier_hotplug_callback, MEMTIER_HOTPLUG_PRI);
 	return 0;
 }
 subsys_initcall(memory_tier_init);
--- a/mm/mempolicy.c~mmmemory_hotplug-implement-numa-node-notifier
+++ a/mm/mempolicy.c
@@ -3788,20 +3788,20 @@ static int wi_node_notifier(struct notif
 			       unsigned long action, void *data)
 {
 	int err;
-	struct memory_notify *arg = data;
+	struct node_notify *arg = data;
 	int nid = arg->status_change_nid;
 
 	if (nid < 0)
 		return NOTIFY_OK;
 
 	switch (action) {
-	case MEM_ONLINE:
+	case NODE_BECAME_MEM_AWARE:
 		err = sysfs_wi_node_add(nid);
 		if (err)
 			pr_err("failed to add sysfs for node%d during hotplug: %d\n",
 			       nid, err);
 		break;
-	case MEM_OFFLINE:
+	case NODE_BECAME_MEMORYLESS:
 		sysfs_wi_node_delete(nid);
 		break;
 	}
@@ -3840,7 +3840,7 @@ static int __init add_weighted_interleav
 		}
 	}
 
-	hotplug_memory_notifier(wi_node_notifier, DEFAULT_CALLBACK_PRI);
+	hotplug_node_notifier(wi_node_notifier, DEFAULT_CALLBACK_PRI);
 	return 0;
 
 err_cleanup_kobj:
--- a/mm/slub.c~mmmemory_hotplug-implement-numa-node-notifier
+++ a/mm/slub.c
@@ -6164,8 +6164,8 @@ static int slab_mem_going_online_callbac
 {
 	struct kmem_cache_node *n;
 	struct kmem_cache *s;
-	struct memory_notify *marg = arg;
-	int nid = marg->status_change_nid;
+	struct node_notify *narg = arg;
+	int nid = narg->status_change_nid;
 	int ret = 0;
 
 	/*
@@ -6217,15 +6217,12 @@ static int slab_memory_callback(struct n
 	int ret = 0;
 
 	switch (action) {
-	case MEM_GOING_ONLINE:
+	case NODE_BECOMING_MEM_AWARE:
 		ret = slab_mem_going_online_callback(arg);
 		break;
-	case MEM_GOING_OFFLINE:
+	case NODE_BECOMING_MEMORYLESS:
 		ret = slab_mem_going_offline_callback(arg);
 		break;
-	case MEM_ONLINE:
-	case MEM_CANCEL_OFFLINE:
-		break;
 	}
 	if (ret)
 		ret = notifier_from_errno(ret);
@@ -6300,7 +6297,7 @@ void __init kmem_cache_init(void)
 			sizeof(struct kmem_cache_node),
 			SLAB_HWCACHE_ALIGN | SLAB_NO_OBJ_EXT, 0, 0);
 
-	hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
+	hotplug_node_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
 
 	/* Able to allocate the per node structures */
 	slab_state = PARTIAL;
_

Patches currently in -mm which might be from osalvador@suse.de are

mmslub-do-not-special-case-n_normal-nodes-for-slab_nodes.patch
mmmemory_hotplug-implement-numa-node-notifier.patch
mmmemory_hotplug-rename-status_change_nid-parameter-in-memory_notify.patch