Re: [PATCH] mm/mm_init: handle alloc_percpu failure in free_area_init_core_hotplug

["David Hildenbrand (Arm)" <david@kernel.org>]

>  	 * The node we allocated has no zone fallback lists. For avoiding
> diff --git a/mm/mm_init.c b/mm/mm_init.c
> index 306ea5c13f54..37fd64ce144d 100644
> --- a/mm/mm_init.c
> +++ b/mm/mm_init.c
> @@ -1536,7 +1536,7 @@ void __init set_pageblock_order(void)
>   * NOTE: this function is only called during memory hotplug
>   */
>  #ifdef CONFIG_MEMORY_HOTPLUG
> -void __ref free_area_init_core_hotplug(struct pglist_data *pgdat)
> +int __ref free_area_init_core_hotplug(struct pglist_data *pgdat)
>  {
>  	int nid = pgdat->node_id;
>  	enum zone_type z;
> @@ -1544,8 +1544,14 @@ void __ref free_area_init_core_hotplug(struct pglist_data *pgdat)
>  
>  	pgdat_init_internals(pgdat);
>  
> -	if (pgdat->per_cpu_nodestats == &boot_nodestats)
> -		pgdat->per_cpu_nodestats = alloc_percpu(struct per_cpu_nodestat);
> +	if (pgdat->per_cpu_nodestats == &boot_nodestats) {
> +		struct per_cpu_nodestat __percpu *p;
> +
> +		p = alloc_percpu(struct per_cpu_nodestat);
> +		if (!p)
> +			return -ENOMEM;
> +		pgdat->per_cpu_nodestats = p;

Is there a need for the temporary variable?

Also how to handle cleanup on error? Or why can we skip cleanup? (what happens
if we get another call to __try_online_node()  later?)

-- 
Cheers,

David