On 16.06.23 00:00, Vishal Verma wrote:
For memory hotplug to consider MHP_MEMMAP_ON_MEMORY behavior, the 'memmap_on_memory' module parameter was a hard requirement. In preparation for the dax/kmem driver to use memmap_on_memory semantics, arrange for the module parameter check to be bypassed via the appropriate mhp_flag. Recall that the kmem driver could contribute huge amounts of hotplugged memory originating from special purposes devices such as CXL memory expanders. In some cases memmap_on_memory may be the /only/ way this new memory can be hotplugged. Hence it makes sense for kmem to have a way to force memmap_on_memory without depending on a module param, if all the other conditions for it are met.
Just let the admin configure it. After all, an admin is involved in configuring the dax/kmem device to begin with. If add_memory() fails you could give a useful hint to the admin.
-- Cheers, David / dhildenb
