Re: gc.c -- possible logic error?

One problem another related with Ruby's memory allocation is that the heap 
size becomes very big very soon (heap_slots is *= 1.8 each time), so you can 
have a lot of memory kept around only for the heaps.

Each RVALUE si 24 bytes, so the sizes in bytes of the heaps and in objects 
are:
10Kobj, 240Kbytes
18Kobj, 432Kbytes
32Kobj, 777Kbytes
58Kobj, 1.4Mbytes
105Kobj, 2.5Mbytes
190Kobj, 4.5Mbytes

So, if you're allocating a lot you can have around 10Mbytes only for the 
heaps -- and they won't get removed unless you're very lucky: if one object 
is kept on a heap, the heap will remain, and it is quite easy to have at 
least one useful object among 190 000 ...

Don't forget that the object count you get from ObjectSpace is *not* the real 
object count. A lot of objects are allocated by the interpreter itself. 
The "object allocation tracking" patch I sent a few times (check rubyforge) 
can tell you how many objects are *really* present.

I'm experimenting around a fixed-size heap allocation scheme, but it has a 
slight performance hit for now.

Sylvain