MmFreeContiguousMemory function (ntddk.h)
The MmFreeContiguousMemory routine releases a range of physically contiguous memory that was allocated by an MmAllocateContiguousMemoryXxx routine.
Syntax
void MmFreeContiguousMemory(
[in] PVOID BaseAddress
);
Parameters
[in] BaseAddress
Pointer to the virtual address of the memory to be freed.
Return value
None
Remarks
The MmFreeContiguousMemory routine frees a block of physically contiguous memory that was allocated by a previous call to the MmAllocateContiguousMemory, MmAllocateContiguousMemorySpecifyCache, or MmAllocateContiguousMemorySpecifyCacheNode routine. The BaseAddress parameter must be the base address that was obtained from the previous call to the MmAllocateContiguousMemoryXxx routine.
A device driver that must use contiguous memory should allocate only what it needs during driver initialization because physical memory is likely to become fragmented as the system runs. Such a driver must deallocate the memory when the driver is done using the memory.
Callers of MmFreeContiguousMemory must be running at IRQL = APC_LEVEL. For Windows Server 2008 and later versions of the Windows operating system, you can also call MmFreeContiguousMemory with IRQL <= DISPATCH_LEVEL. However, you can improve driver performance by calling at APC_LEVEL or below.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Available starting with Windows 2000. |
| Target Platform | Universal |
| Header | ntddk.h (include Wdm.h, Ntddk.h) |
| Library | NtosKrnl.lib |
| DLL | NtosKrnl.exe |
| IRQL | See Remarks section. |
| DDI compliance rules | HwStorPortProhibitedDDIs(storport), IrqlMmDispatch(wdm) |