From: Alison Schofield <alison.schofield@xxxxxxxxx> Changes in v4: - Remove useless export of numa_fill_memblks() (Dan) - Rebase on latest tip tree v3: https://lore.kernel.org/linux-cxl/cover.1687645837.git.alison.schofield@xxxxxxxxx/ ---- Cover Letter: The CXL subsystem requires the creation of NUMA nodes for CFMWS Windows[1] not described in the SRAT. The existing implementation only addresses windows that the SRAT describes completely or not at all. This work addresses the case of partially described CFMWS Windows by extending proximity domains in a portion of a CFMWS window to the entire window. Introduce a NUMA helper, numa_fill_memblks(), to fill gaps in a numa_meminfo memblk address range. Update the CFMWS parsing in the ACPI driver to use numa_fill_memblks() to extend SRAT defined proximity domains to entire CXL windows. An RFC of this patchset was previously posted for CXL folks review here[2]. The RFC feedback led to the implementation here, extending existing memblks (Dan). Also, both Jonathan and Dan influenced the changelog comments in the ACPI patch, with regards to setting expectations on this evolving heuristic. Repeating here to set reviewer expectations: *Note that this heuristic will evolve when CFMWS Windows present a wider range of characteristics. The extension of the proximity domain, implemented here, is likely a step in developing a more sophisticated performance profile in the future. [1] CFMWS is defined in CXL Spec 3.0 Section 9.17.1.3 : https://www.computeexpresslink.org/spec-landing A CXL Fixed Memory Window is a region of Host Physical Address (HPA) Space which routes accesses to CXL Host bridges. The 'S', of CFMWS, stand for the structure that describes the window, hence it's common name, CFMWS. [2] https://lore.kernel.org/linux-cxl/cover.1683742429.git.alison.schofield@xxxxxxxxx/ Alison Schofield (2): x86/numa: Introduce numa_fill_memblks() ACPI: NUMA: Apply SRAT proximity domain to entire CFMWS window arch/x86/include/asm/sparsemem.h | 2 + arch/x86/mm/numa.c | 80 ++++++++++++++++++++++++++++++++ drivers/acpi/numa/srat.c | 11 +++-- include/linux/numa.h | 7 +++ 4 files changed, 97 insertions(+), 3 deletions(-) base-commit: ac442f6a364dd23bc08086f07b4bc4ef8476a9fe -- 2.37.3
