menuconfig CMA size

CMA (Contiguous Memory Allocator) size refers to the amount of contiguous physical memory that is reserved for dynamic memory allocation by the kernel. This memory is typically used for device drivers and other kernel modules that require contiguous memory for DMA (Direct Memory Access) operations.

In the Linux kernel, the CMA size can be configured using the "menuconfig" tool during the kernel compilation process. To access this option, navigate to "General setup" -> "Contiguous Memory Allocator (CMA) support" -> "Default contiguous memory area size" in the menuconfig interface.

The default value for CMA size is 16MB, but it can be increased or decreased depending on the needs of the system. It is important to note that increasing the CMA size may reduce the amount of memory available to user-space processes, so it should be done with caution.