Operating system support for hot-add memory in Windows Server
This topic discusses operating system support for hot-add memory in Windows Server.
This information applies to:
- Windows Server 2008 R2, Enterprise Edition and Datacenter Edition
- Windows Server 2008, Enterprise Edition and Datacenter Edition
- Windows Server 2003, Enterprise Edition and Datacenter Edition
Operating system support for hot-add memory consists of the following:
- Support for the memory device object as described in Section 10.12 of the ACPI 2.0 Specification and in this article.
- A system-supplied kernel-mode driver for ACPI 2.0 memory device objects that describes the memory ranges contained in the objects to the Memory Manager.
- Changes to the Memory Manager to support dynamic addition of memory to a running system.
- Use of the Static Resource Affinity Table (SRAT) to determine the amount and ranges of hot-add memory and to determine whether to enable PAE on x86-based platforms when hot-add memory has addresses over 4GB.
When memory is hot-added to the system, the following steps occur:
- The ACPI BIOS generates an ACPI Notify(1) (device check) to the memory device object that describes the hot-added memory.
- The operating system re-evaluates the _STA method on the memory device object to determine if it now claims that the memory is present.
- If the memory is present, the Plug and Play subsystem loads the system-supplied driver for memory device objects.
- This memory device object driver informs the Memory Manager about the new memory ranges.
- The Memory Manager makes the new memory available to the operating system, drivers, and applications.
Related topics
Hot-Add Memory Support in Windows Server
Static Resource Affinity Table