Contiguous Memory Mapping Functions

The following functions are available to access RTX contiguous memory allocation services:

RtAllocateContiguousMemory allocates a physically contiguous memory address range and maps that memory into the process' virtual address space.
RtFreeContiguousMemory frees a previously allocated physically contiguous memory region.
RtGetPhysicalAddress returns the physical address for the virtual address of a previously allocated physically contiguous memory region.

Programming Considerations

Contiguous memory is always allocated from the non-paged pool of memory maintained by Windows. This pool of memory is relatively small and is rapidly fragmented by the allocations of other drivers and subsystems in Windows shortly after system boot. To avoid failure of large allocations, you should minimize their use and/or ensure that they are accomplished shortly after system boot.

In the Win32 environment, RtGetPhysicalAddress operates only with addresses returned by RtAllocateContiguousMemory.

Programming Example (RTX Contiguous Memory Allocation Calls)

See the RTX Contiguous Memory Allocation Calls Programming Example in the RTX Example Reference. It demonstrates the use of RTX contiguous memory allocation calls.