External RAM filesystem

Chris Johns chrisj at rtems.org
Wed Nov 21 05:44:25 UTC 2007

Joel Sherrill wrote:
> I'm late in the discussion but I proposed a couple of years
> ago adding a configuration item for the IMFS.  If you defined
> a structure with three callback functions, you could change
> where memory was allocated in the IMFS.
> + initialize pool  (default NULL)
> + allocate memory (default malloc)
> + free memory  (default free)
> Change the IMFS code to use the provided functions and
> it can easily be switched.

I assume the allocator is a block type allocator. I would be concerned about 
fragmentation issues if not. I know the heap allocator (malloc) can suffer 
from this but I would not expect major long term use of the IMFS with the 
malloc allocator being used. A block type allocator with a set memory size 
would be fine.

I see 2 types of allocation, the node and the memfile block. Should there be 2 
allocators ?

Does the IMFS have any locking making it thread safe ?

This effects the nature of the allocator.


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