ION buf

file:///home/chenmq/Qualcomm/Hexagon_SDK/3.5.2/docs/APIs_FastRPC.html#Using%20the%20ION%20allocator

The DSP hardware is not well suited for handling dis-contiguous memory, which is commonly the kind of memory users get from a simple “malloc” call. Android provides a memory allocator called ION that can share buffers to clients