MFS RAM footprint

[joey81]

I have MQX 4.0.2 running on a K60 with 128KB RAM.   Memory device is a 256MB Samsung NAND Flash.

Upon boot-up, after calling _io_nandflash_wl_install(), I still have 89344 bytes free.  After calling mfs_nandflash_wl_open(), free RAM drops to 36636 bytes.

Is this the normal RAM footprint of MFS/FFS?  Seems too big.  How do I make it smaller?

Also, each time I list the directory contents (via shell "dir" command), I lose around 20-30 bytes of free RAM.  Anyone got an idea where the leak comes from? 

Thanks in advance!

[Martin_ · Accepted solution]

Hi,

memory size adjustment:

https://community.freescale.com/message/323494#323494

there is one problem with FFS 4.0.2 that I found in my application, that caused a memory leake. The solution was to modify function media_buffer_allocate_internal() in the FFS source file "media_buffer_manager.cpp" as shown below. The difference is line 30 in the code snippet below (_mem_transfer), which changes the buffer ownership to system, so that free() can be called from any task.

static SECTOR_BUFFER * media_buffer_allocate_internal
(
    /* [IN] Buffer length */
    _mem_size length, 

    /* [IN] Flag */
    uint32_t flags, 

    /* [IN] Contigous flag */
    boolean physicallyContiguous
)
{ /* Body */
    SECTOR_BUFFER * resultBuffer;

    switch (flags & (kMediaBufferFlag_NCNB))
    {
        /* Only NCNB memory required. */
        case kMediaBufferFlag_NCNB:
            resultBuffer = (SECTOR_BUFFER *)_wl_mem_alloc_uncache(length);
            break;

        /* No special requirements for the memory type. */
        default:
            {
                resultBuffer = (SECTOR_BUFFER *)_wl_mem_alloc(length);
            }
            break;
    } /* Endswitch */

    _mem_transfer(resultBuffer,_task_get_id(), _mqx_get_system_task_id());
    return resultBuffer;
} /* Endbody */

[joey81]

Excellent!  Both problems are now fixed.

Thanks!