--- old/src/hotspot/share/gc/g1/g1OldGenAllocationTracker.hpp	2020-08-13 04:14:10.211275174 +0000
+++ new/src/hotspot/share/gc/g1/g1OldGenAllocationTracker.hpp	2020-08-13 04:14:10.055272183 +0000
@@ -28,34 +28,55 @@
 #include "gc/g1/heapRegion.hpp"
 #include "memory/allocation.hpp"
 
+class G1AdaptiveIHOPControl;
+
 // Track allocation details in the old generation.
 class G1OldGenAllocationTracker : public CHeapObj<mtGC> {
   // New bytes allocated in old gen between the end of the last GC and
+  // the end of the GC before that. This includes humongous object allocation.
+  size_t _last_period_old_bytes;
+  // New bytes allocated in humongous regions between the end of the last GC and
   // the end of the GC before that.
-  size_t _last_cycle_old_bytes;
-  // The number of seconds between the end of the last GC and
-  // the end of the GC before that.
-  double _last_cycle_duration;
+  size_t _last_period_humongous_bytes;
 
-  size_t _allocated_bytes_since_last_gc;
+  size_t _humongous_bytes_after_last_gc;
+  size_t _humongous_bytes_after_penultimate_gc;
 
-  void reset_cycle_after_gc() {
-    _last_cycle_old_bytes = _allocated_bytes_since_last_gc;
-    _allocated_bytes_since_last_gc = 0;
-  }
+  size_t _allocated_bytes_since_last_gc;
+  size_t _allocated_humongous_bytes_since_last_gc;
 
 public:
   G1OldGenAllocationTracker();
   // Add the given number of bytes to the total number of allocated bytes in the old gen.
   void add_allocated_bytes_since_last_gc(size_t bytes) { _allocated_bytes_since_last_gc += bytes; }
 
-  size_t last_cycle_old_bytes() { return _last_cycle_old_bytes; }
+  void add_allocated_humongous_bytes_since_last_gc(size_t bytes) {
+    _allocated_humongous_bytes_since_last_gc += bytes;
+    _allocated_bytes_since_last_gc += bytes;
+  }
+
+  // Record a humongous allocation during a collection pause.
+  // In g1CollectedHeap, when a humongous allocation fails, the heap will attempt
+  // to trigger a GC and try to allocate the required bytes during it. These bytes
+  // are then not counted in any mutator period but as survived bytes after GC.
+  // Otherwise, they would distort our estimation for how many humongous bytes are
+  // freed in a mutator period.
+  void record_collection_pause_humongous_allocation(size_t bytes) {
+    _humongous_bytes_after_last_gc += bytes;
+  }
 
-  double last_cycle_duration() { return _last_cycle_duration; }
+  size_t last_period_old_bytes() const { return _last_period_old_bytes; }
 
   // Reset stats after a collection.
-  void reset_after_full_gc();
-  void reset_after_young_gc(double allocation_duration_s);
+  void reset_after_gc(size_t humongous_bytes_after_gc);
+
+  // This is used by Adaptive IHOP to sample the old gen allocation rate.
+  // Different from the regular old gen allocation rate, this method considers the
+  // humongous objects that can be reclaimed early by young GCs. Since we cannot
+  // track the life cycle of individual humongous objects, we assume that such
+  // objects were all newly allocated and not survivors, unless more were
+  // reclaimed than allocated.
+  size_t last_period_net_survived_old_bytes() const;
 };
 
 #endif // SHARE_VM_GC_G1_G1OLDGENALLOCATIONTRACKER_HPP
\ No newline at end of file