aclrtReserveMemAddress

Product	Supported
Atlas A3 training products/Atlas A3 inference products	√
Atlas A2 training products/Atlas A2 inference products	√
Atlas 200I/500 A2 inference products	√
Atlas inference products	√
Atlas training products	√

Reserves virtual memory.

This API must 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 "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. 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 or common page flag. The flag must be the same as the memory type of aclrtMallocPhysical. Values: 0: common page 1: huge page

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

This API is not supported in the Ascend RC form of the Atlas 200I/500 A2 inference products.

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.

Parent topic: Memory Management