* gc.c: change full GC timing to keep lower memory usage.

  Extend heap only at
  (1) after major GC
  or
  (2) after several (two times, at current) minor GC
  Details in https://bugs.ruby-lang.org/issues/9607#note-9
  [Bug ruby#9607]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46387 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

Conflicts:
	ChangeLog
	gc.c

gc.c

@@ -541,6 +541,9 @@ typedef struct rb_objspace {
 	int parent_object_is_old;
 
 	int need_major_gc;
+
+	size_t last_major_gc;
+
 	size_t remembered_shady_object_count;
 	size_t remembered_shady_object_limit;
 	size_t old_object_count;
@@ -2998,15 +3001,13 @@ gc_after_sweep(rb_objspace_t *objspace)
 		  (int)heap->total_slots, (int)heap_pages_swept_slots, (int)heap_pages_min_free_slots);
 
     if (heap_pages_swept_slots < heap_pages_min_free_slots) {
-	heap_set_increment(objspace, heap_extend_pages(objspace));
-	heap_increment(objspace, heap);
-
-#if USE_RGENGC
-	if (objspace->rgengc.remembered_shady_object_count + objspace->rgengc.old_object_count > (heap_pages_length * HEAP_OBJ_LIMIT) / 2) {
-	    /* if [old]+[remembered shady] > [all object count]/2, then do major GC */
-	    objspace->rgengc.need_major_gc = GPR_FLAG_MAJOR_BY_RESCAN;
+	if (objspace->rgengc.during_minor_gc && objspace->profile.count - objspace->rgengc.last_major_gc > 2 /* magic number */) {
+	    objspace->rgengc.need_major_gc = GPR_FLAG_MAJOR_BY_NOFREE;
+	}
+	else {
+	    heap_set_increment(objspace, heap_extend_pages(objspace));
+	    heap_increment(objspace, heap);
 	}
-#endif
     }
 
     gc_prof_set_heap_info(objspace);
@@ -4189,6 +4190,7 @@ gc_marks_body(rb_objspace_t *objspace, int full_mark)
     }
     else {
 	objspace->profile.major_gc_count++;
+	objspace->rgengc.last_major_gc = objspace->profile.count;
 	rgengc_mark_and_rememberset_clear(objspace, heap_eden);
     }
 #endif