Re: Guile GC behaviour

[Greg Badros <gjb at cs dot washington dot edu>]

Greg Harvey <Greg.Harvey@thezone.net> writes:

> Greg Badros <gjb@cs.washington.edu> writes:
> 
> > Does the guile gc release heap segments later on?  I have seen Scwm get
> > smaller sometimes, too, but it never seems to shrink back to what it
> > should be.
> 
> It does, but (as I'm sure you're aware) that doesn't necessarily mean
> that the actual size of scwm will get smaller. With some mallocs
> (glibc's, for example) the larger allocation might be mmap'd, but the
> memory used for smaller allocations will hang around forever; so, the
> actual heap segment memory may be returned, but the additional smaller
> allocations (which occur for a lot of objects) mostly won't.

I'm wondering if this could account for the growing Scwm process image
behaviour we've seen for a long time.  It's surprisingly challenging to
debug memory leaks in Scwm given the various memory allocators all
interacting, and the Scheme heap in particular.  I'm open to suggestions 
as to how to confirm or deny that these holes might be the source of the 
"leaks".

Thanks,
Greg