Hi, Ludovic Courtès <l...@gnu.org> skribis:
> Ludovic Courtès <l...@gnu.org> skribis: > >> Consider this code: >> >> ;; https://issues.guix.gnu.org/58631 >> ;; https://github.com/wingo/fibers/issues/65 >> >> (define loss >> (make-vector 1000000)) >> >> (let ((tag (make-prompt-tag "my prompt"))) >> (define handler >> (lambda (k i) >> (when (zero? (modulo i 2000000)) >> (pk 'heap-size (assoc-ref (gc-stats) 'heap-size))) >> >> (call-with-prompt tag >> (lambda () >> (k (modulo (+ 1 i) 10000000))) >> handler))) >> >> (call-with-prompt tag >> (let ((state (current-dynamic-state))) >> (lambda () >> ;; (define (with-dynamic-state state thunk) >> ;; (let ((previous #f)) >> ;; (dynamic-wind >> ;; (lambda () (set! previous (set-current-dynamic-state >> state))) >> ;; thunk >> ;; (lambda () (set-current-dynamic-state previous))))) >> (with-dynamic-state state >> (lambda () >> (let loop ((i 0)) >> (loop (abort-to-prompt tag i))))))) >> handler)) >> >> On Guile 3.0.8, this program exhibits seemingly unbounded heap growth. > > This is fixed by the patch below (tested against the test case above and > the Fibers and Shepherd test cases mentioned before): Pushed as e47a153317c046ea5d335940412999e7dc604c33. > Using a simple heap profiler (more on that later), I noticed that the > stacks allocated at ‘p->stack_bottom’ would be partly retained, > explaining the heap growth. > > I couldn’t pinpoint what exactly is keeping a pointer to the stack, but > what I can tell is that the trick above makes that impossible (because > we disable interior pointer tracing), hence the difference. > > Also, why changing the SCM_DYNSTACK_TYPE_DYNAMIC_STATE entry to an > SCM_DYNSTACK_TYPE_UNWINDER entry would make a difference remains a > mystery to me. > > I’m interested in theories that would explain all this in more detail! > I’ll go ahead with the fix above if there are no objections. I still am. :-) Ludo’.
