On 1/23/26 01:43, Gregory Price wrote:
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.
Great!
--
Cheers
David
