> -static inline void remove_memory(int nid, u64 start, u64 size) {} > +static inline bool remove_memory(int nid, u64 start, u64 size) > +{ > + return -EBUSY; > +} This seems like an appropriate place for a WARN_ONCE(), if someone manages to call remove_memory() with hotplug disabled. BTW, I looked and can't think of a better errno, but -EBUSY probably isn't the best error code, right? > -void remove_memory(int nid, u64 start, u64 size) > +/** > + * remove_memory > + * @nid: the node ID > + * @start: physical address of the region to remove > + * @size: size of the region to remove > + * > + * NOTE: The caller must call lock_device_hotplug() to serialize hotplug > + * and online/offline operations before this call, as required by > + * try_offline_node(). > + */ > +void __remove_memory(int nid, u64 start, u64 size) > { > + > + /* > + * trigger BUG() is some memory is not offlined prior to calling this > + * function > + */ > + if (try_remove_memory(nid, start, size)) > + BUG(); > +} Could we call this remove_offline_memory()? That way, it makes _some_ sense why we would BUG() if the memory isn't offline.