mem-cache: Determine if an MSHR has requests from another cache

To decide whether we allocate upon receiving a response we need to
determine if any of the currently serviced requests (non-deferred
targets) is comming from another cache. This change adds support for
tracking this information in the MSHR.

Change-Id: If1db93c12b6af5813b91b9d6b6e5e196d327f038
Reviewed-on: https://gem5-review.googlesource.com/10422
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>

1 files changed, 1 insertions, 6 deletions

diff --git a/src/mem/cache/cache.cc b/src/mem/cache/cache.cc
index 73c7e1956..e9aec499a 100644
--- a/src/mem/cache/cache.cc
+++ b/src/mem/cache/cache.cc
@@ -1415,7 +1415,6 @@ Cache::recvTimingResp(PacketPtr pkt)
     // First offset for critical word first calculations
     int initial_offset = initial_tgt->pkt->getOffset(blkSize);
 
-    bool from_cache = false;
     MSHR::TargetList targets = mshr->extractServiceableTargets(pkt);
     for (auto &target: targets) {
         Packet *tgt_pkt = target.pkt;
@@ -1437,10 +1436,6 @@ Cache::recvTimingResp(PacketPtr pkt)
                 break; // skip response
             }
 
-            // keep track of whether we have responded to another
-            // cache
-            from_cache = from_cache || tgt_pkt->fromCache();
-
             // unlike the other packet flows, where data is found in other
             // caches or memory and brought back, write-line requests always
             // have the data right away, so the above check for "is fill?"
@@ -1572,7 +1567,7 @@ Cache::recvTimingResp(PacketPtr pkt)
         }
     }
 
-    maintainClusivity(from_cache, blk);
+    maintainClusivity(targets.hasFromCache, blk);
 
     if (blk && blk->isValid()) {
         // an invalidate response stemming from a write line request