[armedbear-devel] Space leak due to threads stuck in LispThread map

[Erik Huelsmann]

Hi James,

On Thu, Jul 19, 2012 at 10:16 PM, Pendergrass, James A. <
James.Pendergrass at jhuapl.edu> wrote:

> Hello all,
> I'm having some trouble with space leakage that looks to be because the
> static map in LispThread isn't letting go of completed JavaThreads.
>  Basically what I'm doing on the Java side looks like:
>
> > class Foo {
> >       public static int main(){
> >               manager = new Manager();
> >               fun     = getLispFunction("processResults");
> >
> >               new Thread() {
> >                       public void run() {
> >                               LispObject res = generateSomeLisp();
> >                               fun.execute(manager, res);
> >                       }.run();
> >               manager = null;
> >               while(1);
> >       }
> > }
>
> The lisp side looks like:
>
> > (defun processResults (manager res)
> >       (let ((*manager* manager))
> >          (declare (special *manager*))
> >          (eval res)))
>
> But the manager never gets destroyed.  I used the eclipse Java Memory
> Analysis tool to track this down to the created JavaThread being referenced
> as a key in the static map variable in LispThread.
>
> Any suggestions on how to get around this?  The whole code base is pretty
> memory intensive so garbage collecting that manager is really a must (and
> cleaning up the thread is probably a good plan too).



One way around this would be to use the LispThread class from the
org.armedbear.lisp package: it removes the thread it creates from the map
when the thread.run() function terminates. The other option would be for
someone to rewrite the map to use a weak hash table algorithm.

The latter is probably the best long term solution anyway....


Bye,


Erik.
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