load procedure seems to leak memory

[Chris Vine <chris@cvine.freeserve.co.uk>]

Hi,

I have noticed that guile-2.0's load procedure seems to leak memory.
This can be observed by the following, which on all the 32-bit machines
on which I have tested (using guile-2.0.9 and guile-2.0.11) exhausts the
scheme memory heap at around 65,000 loads.

  (let loop ([count 0])
    (load "./test-file.scm")
    (when (= (modulo count 100) 0)
          (display count)
          (display " "))
    (when (< count 256000)
          (loop (1+ count))))

In this test case, test-file.scm is a file containing a single scheme
false (#f) expression.

The same can be observed with a similar C implementation:

  #include <libguile.h>
  #include <stdio.h>

  void *func (void *data) {
    scm_c_eval_string ("(load \"./test-file.scm\")");
    return NULL;
  }

  int main (void) {
    int count;
    for(count = 0; count < 256000; ++count) {
      scm_with_guile (func, NULL);
      if (!(count % 100)) {
        printf ("%d ", count);
        fflush (stdout);
      }
    }
    return 0;
  }

primitive-load does not leak.

Is there anything I can do to encourage the VM to release the stale
memory?  In the test case, running (gc)/scm_gc() by hand every 100th
iteration doesn't help unfortunately.

Chris