diff --git a/bin/ikarus b/bin/ikarus
index 9e0b02c..f1d7e9c 100755
Binary files a/bin/ikarus and b/bin/ikarus differ
diff --git a/bin/ikarus-collect.c b/bin/ikarus-collect.c
index 409cafc..96cd09a 100644
--- a/bin/ikarus-collect.c
+++ b/bin/ikarus-collect.c
@@ -275,7 +275,7 @@ static void fix_new_pages(gc_t* gc);
 
 
 ikpcb* 
-ik_collect(int req, ikpcb* pcb){
+ik_collect(int mem_req, ikpcb* pcb){
 
   struct rusage t0, t1;
    
@@ -290,7 +290,7 @@ ik_collect(int req, ikpcb* pcb){
   pcb->collection_id++;
 #ifndef NDEBUG
   fprintf(stderr, "ik_collect entry %d free=%d (collect gen=%d/id=%d)\n",
-      req,
+      mem_req,
       (unsigned int) pcb->allocation_redline
         - (unsigned int) pcb->allocation_pointer,
       gc.collect_gen, pcb->collection_id-1);
@@ -368,6 +368,36 @@ ik_collect(int req, ikpcb* pcb){
    pcb->collect_stime.tv_sec -= 1;
   }
  
+  /* delete all old heap pages */
+  if(pcb->heap_pages){
+    ikpages* p = pcb->heap_pages;
+    do{
+      ikpages* next = p->next;
+      ik_munmap_from_segment(p->base, p->size, pcb);
+      ik_free(p, sizeof(ikpages));
+      p=next;
+    } while(p);
+    pcb->heap_pages = 0;
+  }
+
+  int free_space = 
+    ((unsigned int)pcb->allocation_redline) - 
+    ((unsigned int)pcb->allocation_pointer);
+  if(free_space <= mem_req){
+#ifndef NDEBUG
+    fprintf(stderr, "REQ=%d, got %d\n", mem_req, free_space);
+#endif
+    int memsize = align_to_next_page(mem_req);
+    ik_munmap_from_segment(
+        pcb->heap_base,
+        pcb->heap_size,
+        pcb);
+    ikp ptr = ik_mmap_mixed(memsize+2*pagesize, pcb);
+    pcb->allocation_pointer = ptr;
+    pcb->allocation_redline = ptr+memsize;
+    pcb->heap_base = ptr;
+    pcb->heap_size = memsize+2*pagesize;
+  }
 
   return pcb;
 }
@@ -734,9 +764,11 @@ add_object(gc_t* gc, ikp x, char* caller){
     else if(fst == continuation_tag){
       ikp top = ref(x, off_continuation_top);
       int size = (int) ref(x, off_continuation_size);
+#ifndef NDEBUG
       if(size > 4096){
         fprintf(stderr, "large cont size=0x%08x\n", size);
       }
+#endif
       ikp next = ref(x, off_continuation_next);
       ikp y = gc_alloc_new_ptr(continuation_size, gen, gc) + vector_tag;
       ref(x, -vector_tag) = forward_ptr;
diff --git a/bin/ikarus-runtime.c b/bin/ikarus-runtime.c
index da40c8e..e491afd 100644
--- a/bin/ikarus-runtime.c
+++ b/bin/ikarus-runtime.c
@@ -318,11 +318,6 @@ ik_alloc(ikpcb* pcb, int size){
     return ap;
   } 
   else {
-    static int did_warn = 0;
-    if(! did_warn){
-      fprintf(stderr, "Extension causes leak? %d bytes\n", size);
-      did_warn = 1;
-    }
     if(ap){
       ikpages* p = ik_malloc(sizeof(ikpages));
       p->base = pcb->heap_base;
@@ -354,13 +349,16 @@ void ik_error(ikp args){
 
 
 void ik_stack_overflow(ikpcb* pcb){
+#ifndef NDEBUG
   fprintf(stderr, "entered ik_stack_overflow pcb=0x%08x\n", (int)pcb);
-
+#endif
   set_segment_type(pcb->stack_base, pcb->stack_size, data_mt, pcb);
   
   ikp frame_base = pcb->frame_base;
   ikp underflow_handler = ref(frame_base, -wordsize);
+#ifndef NDEBUG
   fprintf(stderr, "underflow_handler = 0x%08x\n", (int)underflow_handler);
+#endif
   /* capture continuation and set it as next_k */
   ikp k = ik_alloc(pcb, align(continuation_size)) + vector_tag;
   ref(k, -vector_tag) = continuation_tag;