MQX memory alloc issue

daweiyou — Mon, 24 Aug 2015 15:43:11 GMT

Hi:

you know there are two memory management way in mqx, LWMEM or normal MEM,

below code could run correctly on LWMEM, and will fail to alloc memory under MEM(define different function call in small_ram_config.h)

PLS try and suggest.

I debug the code, and could find the issue, issue occurs in step3, while alloc bigger memory after address_at, the previous memory's pointer to next block has not updated;

and I test on MQX4.0.2, 4.1, 4.2, all have this issue.

// _mem_alloc_at will cause a malloc error, this routine will test it

void test_error_alloc_at()

{

void * tm;

//int tm;

volatile unsigned int address_at;

int test;

void * test_pointer;

// get first data, it should be less than 0x2000 0010

tm = malloc(256);

printf("step1: %x\r\n", tm);

// alloc_at the address

address_at=(unsigned int)tm+256+256;

test_pointer = _mem_alloc_at(256, (void*)address_at);

printf("step2: %x, address_at=%x\r\n", test_pointer, address_at);

// get a large data, it will be got after address_at

tm = malloc(256);

printf("step3: %x\r\n", tm);

// get a small data, it will be got before address_at

tm = malloc(128);

printf("step4: %x\r\n", tm);

// get a large data, it will be failure with MQX_CORRUPT_STORAGE_POOL_FREE_LIST

tm = malloc(256);

printf("step5: %x\r\n", tm);

tm = malloc(0xe000);

printf("step6: %x\r\n", tm);

tm = malloc(0x100);

printf("step7: %x\r\n", tm);

}

Re: MQX memory alloc issue

danielchen — Wed, 16 Sep 2015 06:15:09 GMT

Hi Dawei

I copied your code in hello world project, and Enabled MQX_USE_MEM, I didn't see the error.

I tested this code in TWR-K70F120M board.

Regards

Daniel

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MQX memory alloc issue

Re: MQX memory alloc issue