buddy: additional assertions that wait_pri is correct

src/buddy.c

@@ -871,6 +871,29 @@ page_free_locked(struct slashmap *map, unsigned bits, size_t page)
  *
  */
 
+#ifdef DEBUG
+static void
+assert_waitq(buddy_t *buddy)
+{
+	unsigned pri;
+
+	if (buddy->waiting == 0)
+		AZ(buddy->wait_pri);
+
+	for (pri = BUDDY_WAIT_MAXPRI;
+	     pri > buddy->wait_pri;
+	     pri--)
+		assert(VTAILQ_EMPTY(&buddy->reqs_head[pri]));
+
+	assert(pri == buddy->wait_pri);
+	assert(VTAILQ_EMPTY(&buddy->reqs_head[pri]) ==
+	    ! buddy->waiting);
+}
+#define ASSERT_WAITQ(buddy) assert_waitq(buddy)
+#else
+#define ASSERT_WAITQ(buddy) (void)0
+#endif
+
 static inline unsigned
 buddy_reqs_work_list_locked(struct buddy_reqs_head *head);
 
@@ -881,6 +904,8 @@ buddy_wait_work(buddy_t *buddy)
 	struct buddy_reqs_head *head;
 	unsigned pri;
 
+	ASSERT_WAITQ(buddy);
+
 	AN(buddy->waiting);
 	AN(buddy->deficit);
 	AZ(buddy->wait_working);
@@ -895,6 +920,8 @@ buddy_wait_work(buddy_t *buddy)
 	buddy->wait_pri = pri + 1;
 	assert(buddy->wait_pri <= BUDDY_WAIT_MAXPRI);
 	buddy->wait_working = 0;
+
+	ASSERT_WAITQ(buddy);
 }
 
 // external: wait until space is needed (LRU)
@@ -1659,6 +1686,8 @@ buddy_reqs_enqueue(struct buddy_reqs *reqs)
 	CHECK_OBJ(w, I_WAIT_MAGIC);
 	buddy = reqs->buddy;
 
+	ASSERT_WAITQ(buddy);
+
 	assert(w->state == IW_ARMED);
 	w->state = IW_WAITING;
 	assert(reqs->pri <= BUDDY_WAIT_MAXPRI);
@@ -1669,6 +1698,7 @@ buddy_reqs_enqueue(struct buddy_reqs *reqs)
 	if (w->pri > buddy->wait_pri)
 		buddy->wait_pri = w->pri;
 	AZ(pthread_cond_broadcast(&buddy->wait_kick_cond));
+	ASSERT_WAITQ(buddy);
 }
 
 /*
@@ -1727,6 +1757,8 @@ buddy_reqs_wait_cancel(struct buddy_reqs *reqs)
 		AZ(pthread_mutex_lock(&reqs->buddy->map_mtx));
 		AZ(pthread_mutex_lock(&w->wait_mtx));
 
+		ASSERT_WAITQ(buddy);
+
 		if (w->state == IW_WAITING) {
 			AN(buddy->waiting);
 			buddy->waiting--;
@@ -1738,6 +1770,9 @@ buddy_reqs_wait_cancel(struct buddy_reqs *reqs)
 		}
 		if (buddy->waiting && buddy->wait_pri == w->pri)
 			buddy_wait_work(buddy);
+
+		ASSERT_WAITQ(buddy);
+
 		AZ(pthread_mutex_unlock(&reqs->buddy->map_mtx));
 	} else {
 		AZ(pthread_mutex_lock(&w->wait_mtx));