Overview

• Linux Boot Parameters

  • nosoftreserve

• Early Boot

  • Memory Map Creation

    • EFI Memory Map Is Consulted / Created

    • CXL Memory is set aside to be handled by the CXL driver

    • IO Resources are created for each piece

  • NUMA Node Creation

    • ACPI CEDT and SRAT table are used to create Nodes from Proximity domains (PXM)

  • Memory Tier Creation

    • A default tier is created with all nodes.

  • Contiguous Memory Allocation

    • Any requested CMA is allocated from Online nodes

  • Init Finishes, Drivers start probing

• ACPI and PCI Drivers

  • Detect CXL device, marking it for probe by CXL driver

• CXL Driver Operation

  • Base object creation (root, port, memdev)

    • CEDT CFMWS IO Resource creation

  • Decoder creation (root, switch, endpoint)

  • Logical device creation (region, endpoint)

  • Auto-regions surfaced as DAX region

• DAX Driver Operation

  • DAX kmem driver surfaces dax device

    • DAX kmem IO resource creation

  • DAX kmem surfaces memory region to Memory Hotplug to add to page allocator as “driver managed memory”

• Memory Hotplug

  • mhp component surfaces a memory region as multiple memory blocks to the page allocator

  • blocks are onlined into the requested zone (NORMAL or MOVABLE)

  • Memory is marked “Driver Managed” to avoid kexec from using it as region for kernel updates