Am Donnerstag 07 Mai 2009 22:01:11 schrieb Andrew Coppin:
Simon Marlow wrote:
I presume that the reason for this is to avoid handing memory back only to immediately need it again? (I.e., we don't want to be constantly asking the OS to allocate and deallocate memory. Allocate it once and then let the RTS handle it.)
How hard would it be to add a function to ask the RTS to shrink the allocated memory? E.g., you do something that you know consumes lots of RAM, you finish doing it, you know that your live set has probably gone way down now, so you ask the RTS to release some RAM if possible. Would that be difficult?
Another idea, I have no idea how hard or sensible it is: What if the GC detects how much memory is currently used (it does already do that, doesn't it?) and how much is allocated from the OS, and if less than a third or a quarter of the allocated memory is used, return the memory that exceeds twice the used memory to the OS? Behaviour might be configurable by an RTS flag.