How can I extend the buffer in msgq ?

HI:

     My design is based on OMAPL138, In my board , FPGA control AD to acquire data , then I use DSP to read data from fpga, and use http://processors.wiki.ti.com/index.php/Example_application_using_DSP_Link_on_OMAPL1x

this example to communicate with ARM. 

I edit  program below:

#define dsp_arm_datasize 256

typedef struct ControlMsg 
{
MSGQ_MsgHeader header;
Uint16 command;
Char8 arg1[ARG_SIZE];
// Uint32 arg2[128];
Uint16 arg2[dsp_arm_datasize];
} ControlMsg;

array of arg2 is defined my self to transport the data from DSP to ARM. 

Now I want to extend the array of arg2 to realize big data block move. How should I do to realize this?

when I extend the dsp_arm_datasize,  the program can not go well. 

How can I extend the buffer of dsp send to arm in this way?

Best regards！