mem-cache: Remove isTouched field from the CacheBlk

At the moment isTouched is used in the warm-up detection mechanism but
it keeps track of the same information as isValid(). This change
removes it and substitutes its use by isValid().

Change-Id: I611ddf2fa4562ae3b3b2ed2fb74d26abd2e5ec62
Reviewed-on: https://gem5-review.googlesource.com/10427
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>

src/mem/cache/blk.cc

@@ -46,9 +46,6 @@ void
 CacheBlk::insert(const Addr tag, const State is_secure,
                  const int src_master_ID, const uint32_t task_ID)
 {
-    // Touch block
-    isTouched = true;
-
     // Set block tag
     this->tag = tag;
 

src/mem/cache/blk.hh

@@ -109,12 +109,6 @@ class CacheBlk : public ReplaceableEntry
      */
     int set, way;
 
-    /**
-     * Whether this block has been touched since simulation started.
-     * Used to calculate number of used tags.
-     */
-    bool isTouched;
-
     /** Number of references to this block since it was brought in. */
     unsigned refCount;
 
@@ -217,7 +211,6 @@ class CacheBlk : public ReplaceableEntry
         task_id = ContextSwitchTaskId::Unknown;
         status = 0;
         whenReady = MaxTick;
-        isTouched = false;
         refCount = 0;
         srcMasterId = Request::invldMasterId;
         tickInserted = MaxTick;

src/mem/cache/tags/base.cc

@@ -78,14 +78,6 @@ BaseTags::insertBlock(PacketPtr pkt, CacheBlk *blk)
     // Get address
     Addr addr = pkt->getAddr();
 
-    // Update warmup data
-    if (!blk->isTouched) {
-        if (!warmedUp && tagsInUse.value() >= warmupBound) {
-            warmedUp = true;
-            warmupCycle = curTick();
-        }
-    }
-
     // If we're replacing a block that was previously valid update
     // stats for it. This can't be done in findBlock() because a
     // found block might not actually be replaced there if the
@@ -100,7 +92,6 @@ BaseTags::insertBlock(PacketPtr pkt, CacheBlk *blk)
 
     // Previous block, if existed, has been removed, and now we have
     // to insert the new one
-    tagsInUse++;
 
     // Deal with what we are bringing in
     MasterID master_id = pkt->req->masterId();
@@ -111,6 +102,12 @@ BaseTags::insertBlock(PacketPtr pkt, CacheBlk *blk)
     blk->insert(extractTag(addr), pkt->isSecure(), master_id,
                 pkt->req->taskId());
 
+    tagsInUse++;
+    if (!warmedUp && tagsInUse.value() >= warmupBound) {
+        warmedUp = true;
+        warmupCycle = curTick();
+    }
+
     // We only need to write into one tag and one data block.
     tagAccesses += 1;
     dataAccesses += 1;