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- Subject: Re: How to best solve fragmentation issues
- From: Stephen Kellett <lua@...>
- Date: Fri, 22 Feb 2008 16:12:38 +0000
Jens Andersson wrote:
separate heap. I'm not really looking forward to implement a separate
memory-manager, but this way the LUA allocations won't interfere with the
rest of the memory.
Is there a better way to solve this?
You may be better off writing a C extension that provides an API that
simply allocates one large chunk of memory and then
allocates/deallocates that memory explicitly. Four functions should do it:
allocate from heap
deallocate from heap
This removes you from the problem of having to write a full blown memory
manager to replace the Lua one, plus the problems of making your custom
memory manager as fast as the general purpose one (your simple cases may
be faster, but the nasty cases will most likley be worse, or just fail).
It also means that if your images are all the same size or you know the
largest size of the images and how many images you'll need at any one
time you can ensure your heap has this space and also ensure that your
allocate()deallocate() functions prevent fragmentation.
I know I'm advocating explicit memory management in a GC'd world. But
for things like this its almost certainly a better bet. I've come across
some similar cases in the Windows world (where you can force the result
with VirtualAlloc/VirtualFree or
HeapCreate/HeapDestroy/HeapAlloc/HeapFree). The C allocator will never
give you the control so that you can guarantee the result.