aclrtReserveMemAddress

Product	Supported
Atlas 350 Accelerator Card	√
Atlas A3 training product / Atlas A3 inference product	√
Atlas A2 training product / Atlas A2 inference product	√
Atlas 200I/500 A2 inference product	√
Atlas inference product	√
Atlas training product	√

Reserves virtual memory.

This API needs to be used with other APIs to allocate virtual memory with consecutive addresses and maximize the use of physical memory.

      
           aclError aclrtReserveMemAddress(void **virPtr, size_t size, size_t alignment, void *expectPtr, uint64_t flags)

Parameter	Input/Output	Description
virPtr	Output	Pointer to "the pointer to the allocated virtual memory address".
size	Input	Virtual memory size, in bytes. Must not be 0.
alignment	Input	Alignment value of the virtual address. This parameter is reserved and can only be set to 0.
expectPtr	Input	Start address of the virtual memory to be returned. The options are as follows: nullptr: The system automatically allocates a virtual address that meets the alignment requirements. For the Atlas 350 Accelerator Card, only nullptr is supported. Non-nullptr: Specify a start address within the range of 8 TB (16–24 TB). Ensure that the specified address is not occupied and meets the alignment requirements. Otherwise, the virtual memory cannot be reserved and an error will be returned. The alignment rule is as follows: If size is less than 1 GB, expectPtr must be aligned to a power (n) of 2. If size is greater than 1 GB, expectPtr must be aligned to 1 GB. Note: The function of specifying a start address is for trial use and may be changed in later versions. It is not available in commercial products.
flags	Input	Huge page/Common page flag. This parameter is reserved. The recommended value is 0.

0 on success; else, failure. For details, see aclError.

The Ascend RC form of Atlas 200I/500 A2 inference product does not support this API.

To use the virtual memory reserved by this API, only aclrtMemcpyAsync can be called to copy data between two devices in the single-process scenario.

For the API call example, see Virtual Memory Management.

Parent topic: Memory Management