From a200bccc2065d776d0face971610588f438998e7 Mon Sep 17 00:00:00 2001
From: Ron Dreslinski <rdreslin@umich.edu>
Date: Sun, 12 Nov 2006 09:06:15 -0500
Subject: [PATCH] Handle packets being deleted by lower level properly. Fixes
 for Mem Leak associated with Writebacks.

src/mem/cache/miss/mshr_queue.cc:
    Fixes for Mem Leak associated with Writebacks. (Double Delete removed)

--HG--
extra : convert_revision : 7a52ddd57da35995896f2c4438a58aa53f762416
---
 src/mem/cache/cache_impl.hh      | 25 +++++++++++++++++--------
 src/mem/cache/miss/mshr_queue.cc |  5 -----
 2 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/src/mem/cache/cache_impl.hh b/src/mem/cache/cache_impl.hh
index 8acc67b69..df59b0a4f 100644
--- a/src/mem/cache/cache_impl.hh
+++ b/src/mem/cache/cache_impl.hh
@@ -53,6 +53,8 @@
 
 #include "sim/sim_exit.hh" // for SimExitEvent
 
+bool SIGNAL_NACK_HACK;
+
 template<class TagStore, class Buffering, class Coherence>
 bool
 Cache<TagStore,Buffering,Coherence>::
@@ -242,6 +244,11 @@ Cache<TagStore,Buffering,Coherence>::access(PacketPtr &pkt)
         missQueue->handleMiss(pkt, size, curTick + hitLatency);
     }
 
+    if (pkt->cmd == Packet::Writeback) {
+        //Need to clean up the packet on a writeback miss, but leave the request
+        delete pkt;
+    }
+
     return true;
 }
 
@@ -265,6 +272,7 @@ Cache<TagStore,Buffering,Coherence>::getPacket()
 
     assert(!doMasterRequest() || missQueue->havePending());
     assert(!pkt || pkt->time <= curTick);
+    SIGNAL_NACK_HACK = false;
     return pkt;
 }
 
@@ -273,16 +281,15 @@ void
 Cache<TagStore,Buffering,Coherence>::sendResult(PacketPtr &pkt, MSHR* mshr,
                                                 bool success)
 {
-    if (success && !(pkt && (pkt->flags & NACKED_LINE))) {
-        if (!mshr->pkt->needsResponse()
-            && !(mshr->pkt->cmd == Packet::UpgradeReq)
-            && (pkt && (pkt->flags & SATISFIED))) {
-            //Writeback, clean up the non copy version of the packet
-            delete pkt;
-        }
+    if (success && !(SIGNAL_NACK_HACK)) {
+        //Remember if it was an upgrade because writeback MSHR's are removed
+        //in Mark in Service
+        bool upgrade = (mshr->pkt && mshr->pkt->cmd == Packet::UpgradeReq);
+
         missQueue->markInService(mshr->pkt, mshr);
+
         //Temp Hack for UPGRADES
-        if (mshr->pkt && mshr->pkt->cmd == Packet::UpgradeReq) {
+        if (upgrade) {
             assert(pkt);  //Upgrades need to be fixed
             pkt->flags &= ~CACHE_LINE_FILL;
             BlkType *blk = tags->findBlock(pkt);
@@ -300,6 +307,7 @@ Cache<TagStore,Buffering,Coherence>::sendResult(PacketPtr &pkt, MSHR* mshr,
         }
     } else if (pkt && !pkt->req->isUncacheable()) {
         pkt->flags &= ~NACKED_LINE;
+        SIGNAL_NACK_HACK = false;
         pkt->flags &= ~SATISFIED;
         pkt->flags &= ~SNOOP_COMMIT;
 
@@ -404,6 +412,7 @@ Cache<TagStore,Buffering,Coherence>::snoop(PacketPtr &pkt)
                     assert(!(pkt->flags & SATISFIED));
                     pkt->flags |= SATISFIED;
                     pkt->flags |= NACKED_LINE;
+                    SIGNAL_NACK_HACK = true;
                     ///@todo NACK's from other levels
                     //warn("NACKs from devices not connected to the same bus "
                     //"not implemented\n");
diff --git a/src/mem/cache/miss/mshr_queue.cc b/src/mem/cache/miss/mshr_queue.cc
index d3a7a7933..6cb62429d 100644
--- a/src/mem/cache/miss/mshr_queue.cc
+++ b/src/mem/cache/miss/mshr_queue.cc
@@ -198,11 +198,6 @@ MSHRQueue::markInService(MSHR* mshr)
     //assert(mshr == pendingList.front());
     if (!mshr->pkt->needsResponse() && !(mshr->pkt->cmd == Packet::UpgradeReq)) {
         assert(mshr->getNumTargets() == 0);
-        if ((mshr->pkt->flags & SATISFIED) && (mshr->pkt->cmd == Packet::Writeback)) {
-            //Writeback hit, so delete it
-            //otherwise the consumer will delete it
-            delete mshr->pkt->req;
-        }
         deallocate(mshr);
         return;
     }