8253815: Remove unused HeapRegionManager::_num_committed from SA

Reviewed-by: tschatzl, cjplummer

Author: kstefanj

src/hotspot/share/gc/g1/vmStructs_g1.hpp

@@ -53,7 +53,6 @@
   nonstatic_field(G1HeapRegionTable, _shift_by,         uint)                 \
                                                                               \
   nonstatic_field(HeapRegionManager, _regions,          G1HeapRegionTable)    \
-  nonstatic_field(HeapRegionManager, _num_committed,    uint)                 \
                                                                               \
   volatile_nonstatic_field(G1CollectedHeap, _summary_bytes_used, size_t)      \
   nonstatic_field(G1CollectedHeap, _hrm,                HeapRegionManager*)   \

src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/gc/g1/HeapRegionManager.java

@@ -42,8 +42,6 @@
 public class HeapRegionManager extends VMObject {
     // G1HeapRegionTable _regions
     static private long regionsFieldOffset;
-    // uint _committed_length
-    static private CIntegerField numCommittedField;
 
     static {
         VM.registerVMInitializedObserver(new Observer() {
@@ -57,7 +55,6 @@ static private synchronized void initialize(TypeDataBase db) {
         Type type = db.lookupType("HeapRegionManager");
 
         regionsFieldOffset = type.getField("_regions").getOffset();
-        numCommittedField = type.getCIntegerField("_num_committed");
     }
 
     private G1HeapRegionTable regions() {
@@ -74,10 +71,6 @@ public long length() {
         return regions().length();
     }
 
-    public long committedLength() {
-        return numCommittedField.getValue(addr);
-    }
-
     public Iterator<HeapRegion> heapRegionIterator() {
         return regions().heapRegionIterator(length());
     }