ruby-1.9.3-disable_lazy_sweep.patch

diff --git a/gc.c b/gc.c
index 0f84e22..8efd053 100644
--- a/gc.c
+++ b/gc.c
@@ -393,6 +393,7 @@ typedef struct rb_objspace {
     struct gc_list *global_list;
     size_t count;
     int gc_stress;
+    int gc_disable_lazy_sweep;
 } rb_objspace_t;
 
 #if defined(ENABLE_VM_OBJSPACE) && ENABLE_VM_OBJSPACE
@@ -419,6 +420,7 @@ 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
@@ -445,6 +447,7 @@ 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;
 
@@ -480,6 +483,15 @@ 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;
+    }
 }
 
 #if defined(ENABLE_VM_OBJSPACE) && ENABLE_VM_OBJSPACE
@@ -963,6 +975,51 @@ 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;
+}
+
 VALUE rb_mGC;
 
 void
@@ -2273,9 +2330,11 @@ gc_lazy_sweep(rb_objspace_t *objspace)
     int res;
     INIT_GC_PROF_PARAMS;
 
-    if (objspace->flags.dont_lazy_sweep)
-        return garbage_collect(objspace);
-
+    if (ruby_gc_disable_lazy_sweep || objspace->flags.dont_lazy_sweep) {
+	if (!heaps_increment(objspace)) {
+	    return garbage_collect(objspace);
+	}
+    }
 
     if (!ready_to_gc(objspace)) return TRUE;
 
@@ -3674,6 +3733,8 @@ 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);