From 9bb385938ead40970b54971cf03a460df9bce4d7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E4=BA=91=E9=A3=8E?= <cloudwu@gmail.com>
Date: Tue, 16 Oct 2012 10:23:43 +0800
Subject: [PATCH] add write barrier

---
 skynet-src/skynet_mq.c | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/skynet-src/skynet_mq.c b/skynet-src/skynet_mq.c
index 9d682a41..b6f767f6 100644
--- a/skynet-src/skynet_mq.c
+++ b/skynet-src/skynet_mq.c
@@ -48,25 +48,28 @@ skynet_globalmq_push(struct message_queue * queue) {
 	q->queue[tail] = queue;
 	__sync_synchronize();
 	q->flag[tail] = true;
+	__sync_synchronize();
 }
 
 struct message_queue * 
 skynet_globalmq_pop() {
 	struct global_queue *q = Q;
-    uint32_t head =  q->head;
-    uint32_t head_ptr = GP(head);
-    if (head_ptr == GP(q->tail)) {
-        return NULL;
-    }
-    
+	uint32_t head =  q->head;
+	uint32_t head_ptr = GP(head);
+	if (head_ptr == GP(q->tail)) {
+		return NULL;
+	}
+
+	__sync_synchronize();
+
 	if(!q->flag[head_ptr]) {
         return NULL;
 	}
 
-    struct message_queue * mq = q->queue[head_ptr];
-    if (!__sync_bool_compare_and_swap(&q->head, head, head+1)) {
-        return NULL;
-    }
+	struct message_queue * mq = q->queue[head_ptr];
+	if (!__sync_bool_compare_and_swap(&q->head, head, head+1)) {
+		return NULL;
+	}
 	q->flag[head_ptr] = false;
 
 	return mq;