On Thu, Jan 22, 2026 at 11:49:48PM +0100, David Hildenbrand (Red Hat) wrote: > > I'm merely wondering why, in the new world, you would even want the offline > state. > > So what are the use cases for that? >
I don't have one, and in the 5-patch series I killed it. You are right, it makes no sense. However: > Why would user space possibly want that? [plugged-in offline blocks] > I don't think anyone does. This is baggage. The CXL driver auto-creates dax_kmem w/ offline memory blocks Changing this behavior breaks existing systems :[ > Can't ndctl just use the old (existing) interface if such an operation is > requested, and the new one (you want to add) when we want to do something > reasonable (actually use system ram? :) ). I think we're in agreement, I think I'm doing a poor job of explaining the interconnected issues. summarizing the long email: cxl/region + dax/cxl.c + dax/bus.c auto-probe baggage for BIOS-configured regions prevents any userland policy from from being plumbed from cxl to dax. There's no interposition step. So yes - new interfaces would resolve this and the old interfaces could be left for compat. ~Gregory
