postponed_freelist.diff

diff --git a/vm_core.h b/vm_core.h
index 4c6e3c2..c65dcc1 100644
--- a/vm_core.h
+++ b/vm_core.h
@@ -389,7 +389,7 @@ typedef struct rb_vm_struct {
     /* hook */
     rb_hook_list_t event_hooks;
 
-    struct rb_postponed_job_struct *postponed_job;
+    struct rb_postponed_job_struct *postponed_job, *postponed_job_freelist;
 
     int src_encoding_index;
 
diff --git a/vm_trace.c b/vm_trace.c
index d01ff8c..3c32218 100644
--- a/vm_trace.c
+++ b/vm_trace.c
@@ -1385,7 +1385,14 @@ rb_postponed_job_register(unsigned int flags, rb_postponed_job_func_t func, void
 {
     rb_thread_t *th = GET_THREAD();
     rb_vm_t *vm = th->vm;
-    rb_postponed_job_t *pjob = (rb_postponed_job_t *)ruby_xmalloc(sizeof(rb_postponed_job_t));
+    rb_postponed_job_t *pjob;
+
+    if (vm->postponed_job_freelist) {
+	pjob = vm->postponed_job_freelist;
+	vm->postponed_job_freelist = pjob->next;
+    } else {
+	pjob = (rb_postponed_job_t *)ruby_xmalloc(sizeof(rb_postponed_job_t));
+    }
     if (pjob == NULL) return 0; /* failed */
 
     pjob->flags = flags;
@@ -1425,7 +1432,10 @@ rb_postponed_job_flush(rb_vm_t *vm)
     while (pjob) {
 	next_pjob = pjob->next;
 	pjob->func(pjob->data);
-	ruby_xfree(pjob);
+
+	pjob->next = vm->postponed_job_freelist;
+	vm->postponed_job_freelist = pjob;
+
 	pjob = next_pjob;
     }
 }