ruby-2.0.0-disable_lazy_sweep.patch

diff --git a/gc.c b/gc.c
index ace7a08..07b7521 100644
--- a/gc.c
+++ b/gc.c
@@ -253,6 +253,7 @@ typedef struct rb_objspace {
     size_t total_allocated_object_num;
     size_t total_freed_object_num;
     int gc_stress;
+    int gc_disable_lazy_sweep;
 
     struct mark_func_data_struct {
   void *data;
@@ -284,6 +285,7 @@ int *ruby_initial_gc_stress_ptr = &rb_objspace.gc_stress;
 #define deferred_final_list	objspace->final.deferred
 #define global_List		objspace->global_list
 #define ruby_gc_stress		objspace->gc_stress
+#define ruby_gc_disable_lazy_sweep	objspace->gc_disable_lazy_sweep
 #define initial_malloc_limit	initial_params.initial_malloc_limit
 #define initial_heap_min_slots	initial_params.initial_heap_min_slots
 #define initial_free_min	initial_params.initial_free_min
@@ -2039,7 +2041,7 @@ gc_prepare_free_objects(rb_objspace_t *objspace)
 {
     int res;
 
-    if (objspace->flags.dont_lazy_sweep)
+    if (ruby_gc_disable_lazy_sweep || objspace->flags.dont_lazy_sweep)
         return garbage_collect(objspace);
 
 
@@ -3287,10 +3289,56 @@ rb_gc_disable(void)
     return old ? Qtrue : Qfalse;
 }
 
+/*
+ *  call-seq:
+ *     GC.enable_lazy_sweep    -> true or false
+ *
+ *  Enables lazy sweep algorithm, returning <code>true</code> if lazy
+ *  sweep was previously disabled.
+ *
+ *     GC.disable_lazy_sweep   #=> false
+ *     GC.enable_lazy_sweep    #=> true
+ *     GC.enable_lazy_sweep    #=> false
+ *
+ */
+
+VALUE
+rb_gc_enable_lazy_sweep(void)
+{
+    rb_objspace_t *objspace = &rb_objspace;
+    int old = ruby_gc_disable_lazy_sweep;
+
+    ruby_gc_disable_lazy_sweep = FALSE;
+    return old ? Qtrue : Qfalse;
+}
+
+/*
+ *  call-seq:
+ *     GC.disable_lazy_sweep    -> true or false
+ *
+ *  Disables lazy sweep algorithm, returning <code>true</code> if lazy
+ *  sweep was already disabled.
+ *
+ *     GC.disable_lazy_sweep   #=> false
+ *     GC.disable_lazy_sweep   #=> true
+ *
+ */
+
+VALUE
+rb_gc_disable_lazy_sweep(void)
+{
+    rb_objspace_t *objspace = &rb_objspace;
+    int old = ruby_gc_disable_lazy_sweep;
+
+    ruby_gc_disable_lazy_sweep = TRUE;
+    return old ? Qtrue : Qfalse;
+}
+
 void
 rb_gc_set_params(void)
 {
     char *malloc_limit_ptr, *heap_min_slots_ptr, *free_min_ptr;
+    char *disable_lazy_sweep_ptr;
 
     if (rb_safe_level() > 0) return;
 
@@ -3326,6 +3374,15 @@ rb_gc_set_params(void)
 	    initial_free_min = free_min_i;
 	}
     }
+
+    disable_lazy_sweep_ptr = getenv("RUBY_GC_DISABLE_LAZY_SWEEP");
+    if (disable_lazy_sweep_ptr != NULL) {
+	int disable_lazy_sweep_i = atoi(disable_lazy_sweep_ptr);
+	if (RTEST(ruby_verbose))
+	    fprintf(stderr, "disable_lazy_sweep=%d (%d)\n",
+		    disable_lazy_sweep_i, rb_objspace.gc_disable_lazy_sweep);
+	rb_objspace.gc_disable_lazy_sweep = disable_lazy_sweep_i;
+    }
 }
 
 void
@@ -4487,6 +4544,8 @@ Init_GC(void)
     rb_define_singleton_method(rb_mGC, "start", rb_gc_start, 0);
     rb_define_singleton_method(rb_mGC, "enable", rb_gc_enable, 0);
     rb_define_singleton_method(rb_mGC, "disable", rb_gc_disable, 0);
+    rb_define_singleton_method(rb_mGC, "enable_lazy_sweep", rb_gc_enable_lazy_sweep, 0);
+    rb_define_singleton_method(rb_mGC, "disable_lazy_sweep", rb_gc_disable_lazy_sweep, 0);
     rb_define_singleton_method(rb_mGC, "stress", gc_stress_get, 0);
     rb_define_singleton_method(rb_mGC, "stress=", gc_stress_set, 1);
     rb_define_singleton_method(rb_mGC, "count", gc_count, 0);