--- a/drivers/xen/balloon.c~xen-balloon-try-to-merge-system-ram-resources +++ a/drivers/xen/balloon.c @@ -331,7 +331,7 @@ static enum bp_state reserve_additional_ mutex_unlock(&balloon_mutex); /* add_memory_resource() requires the device_hotplug lock */ lock_device_hotplug(); - rc = add_memory_resource(nid, resource, MHP_NONE); + rc = add_memory_resource(nid, resource, MEMHP_MERGE_RESOURCE); unlock_device_hotplug(); mutex_lock(&balloon_mutex);