data transfer issue on MIC

Hello!

I'm optimizing an application with Xeon Phi 5110P. And its initialization part looks as below:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

typedef struct {
	float *W[7];
	float *B[7];
	//float *dW[7];
	//float *dB[7];
} net;

int main(int argc, char *argv[])
{
	int a[8];
	a[:] = 1024;
	//a[:] = 64;
	int arr1[7], arr2[7];
	arr1[0:7] = a[0:7]*a[1:7];
	arr2[0:7] = a[1:7];

	net n1;

	for(int i=0; i<7; i++)
	{
		n1.W[i] = new float[arr1[i]];
		memset(n1.W[i], 0, arr1[i]*sizeof(float));
		#pragma offload_transfer target(mic:0) in(n1.W[i:1]:extent(0:arr1[i]) alloc_if(1) free_if(0))
		n1.B[i] = new float[arr2[i]];
		memset(n1.B[i], 0, arr2[i]*sizeof(float));
		#pragma offload_transfer target(mic:0) in(n1.B[i:1]:extent(0:arr2[i]) alloc_if(1) free_if(0))
	}
	//calculation on phi

	#pragma offload_transfer target(mic:0) out(n1.W[0:7]:extent(0:arr1[0:7]) alloc_if(0) free_if(1))
	#pragma offload_transfer target(mic:0) out(n1.B[0:7]:extent(0:arr2[0:7]) alloc_if(0) free_if(1))

	return 0;
}

In the initialization step, I tried to allocate memory for the arrays of pointers on the host and transfer data to Phi. If I set the elements of array a with 64, the program runs correctly. But when I tried to set array a as 1024 as above, the program gives "offload error: allocation (base=0x10d6010, size=8388608) overlaps with existing allocation (base=0xcd6000, size=8388608)".

I'm wondering whether this problem comes from memory size limits or other reasons.

I'd appreciate if someone could help to explain this problem. thx