On 6/7/19 12:27 PM, Dan Williams wrote:
In support of optionally allowing either application-exclusive and
core-kernel-mm managed access to differentiated memory, claim
EFI_MEMORY_SP ranges for exposure as device-dax instances by default.
Such instances can be directly owned / mapped by a
platform-topology-aware application. Alternatively, with the new kmem
facility , the administrator has the option to instead designate that
those memory ranges be hot-added to the core-kernel-mm as a unique
memory numa-node. In short, allow for the decision about what software
agent manages specific-purpose memory to be made at runtime.
It's probably worth noting that the reason the memory lands into the
state of being controlled by device-dax by default is that device-dax is
nice. It's actually willing and able to give up ownership of the memory
when we ask. If we added to the core-mm, we'd almost certainly not be
able to get it back reliably.
Anyway, thanks for doing these, and I really hope that the world's
BIOSes actually use this flag. For the series:
Reviewed-by: Dave Hansen <dave.hansen(a)linux.intel.com>