From 701a666a4328ee30f3cd7cbf4cd698a7ff0105e5 Mon Sep 17 00:00:00 2001
From: yeom <yeom>
Date: Mon, 4 Apr 2011 01:14:06 +0000
Subject: [PATCH] bug fix on the oooJava queue: when tries to add a vector
 item, get rid of finished item in front of it.

---
 Robust/src/Runtime/mlp_runtime.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/Robust/src/Runtime/mlp_runtime.c b/Robust/src/Runtime/mlp_runtime.c
index b0f9b168..768e9c0e 100644
--- a/Robust/src/Runtime/mlp_runtime.c
+++ b/Robust/src/Runtime/mlp_runtime.c
@@ -242,6 +242,7 @@ int ADDTABLE(MemoryQueue *q, REntry *r) {
   if(!isHashtable(q->tail)) {
     //Fast Case
     MemoryQueueItem* tail=q->tail;
+    //optimization only on next line....DO NOT TRUST THIS TO RETIRE PARENTS!!!!
     if (isParent(r) && tail->total==0 && q->tail==q->head) {
       return READY;
     }
@@ -509,9 +510,11 @@ int ADDVECTOR(MemoryQueue *Q, REntry *r) {
     Q->tail->next=(MemoryQueueItem*)V;
     //************NEED memory barrier here to ensure compiler does not cache Q.tail.status******
     MBARRIER();
-    if (Q->tail->status==READY&&Q->tail->total==0) {
+    if (Q->tail->status==READY&&Q->tail->total==0&&Q->head==Q->tail) {
       //previous Q item is finished
       V->item.status=READY;
+      //Get rid of item in front of us...
+      CAS((unsigned INTPTR*)&(Q->head), (unsigned INTPTR)Q->tail, (unsigned INTPTR)V);
     }
     Q->tail=(MemoryQueueItem*)V;
     // handle the the queue item case
@@ -532,6 +535,10 @@ int ADDVECTOR(MemoryQueue *Q, REntry *r) {
     if (Q->tail->status==READY) { 
       V->item.status=READY;
     }
+    if (Q->tail->total==0&&Q->head==Q->tail) {
+      //may need to remove things
+      CAS((unsigned INTPTR*)&(Q->head), (unsigned INTPTR)Q->tail, (unsigned INTPTR)V);
+    }
     Q->tail=(MemoryQueueItem*)V;
   }
 
@@ -547,7 +554,8 @@ int ADDVECTOR(MemoryQueue *Q, REntry *r) {
   V->index++;
   //*****NEED memory barrier here to ensure compiler does not cache V.status*********
   r->qitem=(MemoryQueueItem *)V;
-  if (BARRIER() && V->item.status==READY) {
+  MBARRIER();
+  if (V->item.status==READY) {
     void* flag=NULL;
     flag=(void*)LOCKXCHG((unsigned INTPTR*)&(V->array[index]), (unsigned INTPTR)flag);
     if (flag!=NULL) {
-- 
2.34.1