From 67929de108479dbb78496b61af5c24072fc16d8d Mon Sep 17 00:00:00 2001 From: Oscar Salvador Date: Mon, 16 Jun 2025 15:51:46 +0200 Subject: mm,memory_hotplug: implement numa node notifier 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 having memory to not having memory and vice versa. Implement a specific notifier for numa nodes when their state gets changed, which will later be used by those consumers that are only interested in numa node state changes. Add documentation as well. [dan.carpenter@linaro.org: set failure reason in offline_pages()] Link: https://lkml.kernel.org/r/be4fd31b-7d09-46b0-8329-6d0464ffa7a5@sabinyo.mountain Link: https://lkml.kernel.org/r/20250616135158.450136-4-osalvador@suse.de Signed-off-by: Oscar Salvador Signed-off-by: Dan Carpenter Reviewed-by: Jonathan Cameron Reviewed-by: Harry Yoo Reviewed-by: Vlastimil Babka Acked-by: David Hildenbrand Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Rakie Kim Signed-off-by: Andrew Morton --- drivers/base/node.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) (limited to 'drivers/base/node.c') diff --git a/drivers/base/node.c b/drivers/base/node.c index 6cbeca45c451..6d66382dae65 100644 --- a/drivers/base/node.c +++ b/drivers/base/node.c @@ -112,6 +112,27 @@ static const struct attribute_group *node_access_node_groups[] = { 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; -- cgit v1.2.3