Ross Zwisler of Intel posted a new patch to the Linux kernel, with support for the ACPI 6.2 HMAT (Heterogeneous Memory Attribute Table).
This series adds kernel support for the Heterogeneous Memory Attribute Table (HMAT) table, newly defined in ACPI 6.2. The HMAT table, in concert with the existing System Resource Affinity Table (SRAT), provides users with information about memory initiators and memory targets in the system. A “memory initiator” in this case is any device such as a CPU or a separate memory I/O device that can initiate a memory request. A “memory target” is a CPU-accessible physical address range. The HMAT provides performance information (expected latency and bandwidth, etc.) for various (initiator,target) pairs. This is mostly motivated by the need to optimally use performance-differentiated DRAM, but it also allows us to describe the performance characteristics of persistent memory. The purpose of this RFC is to gather feedback on the different options for enabling the HMAT in the kernel and in userspace.
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See the patch, especially more details in comment documentation in part 0, on the linux-acpi mailing list posting.