version_1.patch

Index: gc.c
===================================================================
--- gc.c	(revision 20686)
+++ gc.c	(working copy)
@@ -1,4 +1,4 @@
-/**********************************************************************
+/*
 
   gc.c -
 
@@ -497,6 +497,8 @@
 # define STACK_LEVEL_MAX 655300
 #endif
 
+
+
 #ifdef C_ALLOCA
 # define SET_STACK_END VALUE stack_end; alloca(0);
 # define STACK_END (&stack_end)
@@ -560,12 +562,32 @@
     return STACK_LENGTH;
 }
 
+/* note not good for those whose stacks grow upward, yet */
+void *deepest_spot_so_far = (void *) -1;
+
+void
+clean_stack()
+{
+    SET_STACK_END;
+    if((void *) STACK_END < deepest_spot_so_far) {
+	deepest_spot_so_far = STACK_END;
+	return;
+    }
+    if((void *) STACK_END == deepest_spot_so_far)
+	return;
+
+    memset(deepest_spot_so_far, '\0', ((int) STACK_END - (int) deepest_spot_so_far - 1));
+    deepest_spot_so_far = STACK_END;
+
+}
+
 int
 ruby_stack_check()
 {
     int ret;
-
     CHECK_STACK(ret);
+    clean_stack();
+    
     return ret;
 }
 
@@ -1431,6 +1453,7 @@
 static void
 garbage_collect()
 {
+    clean_stack(); // so we can call GC.start to note the current depth
     struct gc_list *list;
     struct FRAME * volatile frame; /* gcc 2.7.2.3 -O2 bug??  */
     jmp_buf save_regs_gc_mark;

version_2_more_aggressive.patch

Index: gc.c
===================================================================
--- gc.c        (revision 20686)
+++ gc.c        (working copy)
@@ -1,4 +1,4 @@
-/**********************************************************************
+/*

   gc.c -

@@ -497,6 +497,8 @@
 # define STACK_LEVEL_MAX 655300
 #endif

+
+
 #ifdef C_ALLOCA
 # define SET_STACK_END VALUE stack_end; alloca(0);
 # define STACK_END (&stack_end)
@@ -560,12 +562,40 @@
     return STACK_LENGTH;
 }

+/* note not good for those whose stacks grow upward, yet */
+void *deepest_spot_so_far = (void *) -1;
+
+void note_stack_depth_for_cleaning()
+{
+    SET_STACK_END;
+    if((void *) STACK_END < deepest_spot_so_far) {
+       deepest_spot_so_far = STACK_END;
+    }
+}
+
+void
+clean_stack()
+{
+    SET_STACK_END;
+    if((void *) STACK_END < deepest_spot_so_far) {
+       deepest_spot_so_far = STACK_END;
+       return;
+    }
+    if((void *) STACK_END == deepest_spot_so_far)
+       return;
+
+    memset(deepest_spot_so_far, '\0', ((int) STACK_END - (int) deepest_spot_so_far - 1));
+    deepest_spot_so_far = STACK_END;
+
+}
+
 int
 ruby_stack_check()
 {
     int ret;
-
     CHECK_STACK(ret);
+    clean_stack();
+
     return ret;
 }

@@ -1431,6 +1461,7 @@
 static void
 garbage_collect()
 {
+    clean_stack(); // so we can call GC.start to note the current depth
     struct gc_list *list;
     struct FRAME * volatile frame; /* gcc 2.7.2.3 -O2 bug??  */
     jmp_buf save_regs_gc_mark;
Index: rubysig.h
===================================================================
--- rubysig.h   (revision 20686)
+++ rubysig.h   (working copy)
@@ -80,8 +80,10 @@
 RUBY_EXTERN int rb_thread_critical;
 RUBY_EXTERN int rb_thread_pending;
 void rb_thread_schedule _((void));
+void note_stack_depth_for_cleaning();
 #if defined(HAVE_SETITIMER) || defined(_THREAD_SAFE)
 # define CHECK_INTS do {\
+    note_stack_depth_for_cleaning();\
     if (!(rb_prohibit_interrupt || rb_thread_critical)) {\
        if (rb_thread_pending) rb_thread_schedule();\
        if (rb_trap_pending) rb_trap_exec();\