On Fri, 16 Jun 2023 09:46:59 +0200 David Hildenbrand <david@xxxxxxxxxx> wrote: > 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. > Agreed. If it were just the default then fine, but making it the only option limits admin choices. Jonathan
