[ECOS] dynamic allocation memory

[ECOS] dynamic allocation memory

[pengyu xue]

Hi, all:
 
         I use the malloc function in my device driver, but it seems
something is wrong with this function. So I wonder that ecos-131 support
the dynamic memory allocation in the target vrc4300-4373.  Can someone
tell me more information about this? And I used  memory pool, the same
result I meet. How to use the memory pool functions?
         Thanks!

Re: [ECOS] dynamic allocation memory

[Andrew Lunn]

> Hi, all:
>  
>          I use the malloc function in my device driver, but it seems
> something is wrong with this function. 

You say device driver. Do you mean ISR and DSR? If so, its a bad idea
to use malloc. malloc will need to use some sort of mutex primitive to
protect its data structures from multiple threads executing it
simultaniously. ISR and DSR cannot block so these primitives don't
work. 

Somewhere there is a document which states which functions you can
call in a DSR/ISR. For mempools the try get function will probably
work, but you have to be prepaired for it to return no memory.

        Andrew

RE: [ECOS] dynamic allocation memory

[Gary Thomas]

On 06-Sep-2000 pengyu xue wrote:
> 
> Hi, all:
>  
>          I use the malloc function in my device driver, but it seems
> something is wrong with this function. So I wonder that ecos-131 support
> the dynamic memory allocation in the target vrc4300-4373.  Can someone
> tell me more information about this? And I used  memory pool, the same
> result I meet. How to use the memory pool functions?

What does 'something is wrong' mean?  Does it work at all?  Do you run
out of malloc memory before you think you should?  We'll need more data
before we can help much.

As was also pointed out, calling malloc() in an ISR or even DSR is probably
not a really good idea.  Can you tell us more about what you're trying to
do?