8246274: G1 old gen allocation tracking is not in a separate class

Add G1OldGenAllocationTracker

Reviewed-by: tschatzl, phh

src/hotspot/share/gc/g1/g1CollectedHeap.cpp

@@ -871,7 +871,8 @@ HeapWord* G1CollectedHeap::attempt_allocation_humongous(size_t word_size) {
       result = humongous_obj_allocate(word_size);
       if (result != NULL) {
         size_t size_in_regions = humongous_obj_size_in_regions(word_size);
-        policy()->add_bytes_allocated_in_old_since_last_gc(size_in_regions * HeapRegion::GrainBytes);
+        policy()->old_gen_alloc_tracker()->
+          add_allocated_bytes_since_last_gc(size_in_regions * HeapRegion::GrainBytes);
         return result;
       }
 
@@ -4092,7 +4093,8 @@ void G1CollectedHeap::post_evacuate_collection_set(G1EvacuationInfo& evacuation_
 }
 
 void G1CollectedHeap::record_obj_copy_mem_stats() {
-  policy()->add_bytes_allocated_in_old_since_last_gc(_old_evac_stats.allocated() * HeapWordSize);
+  policy()->old_gen_alloc_tracker()->
+    add_allocated_bytes_since_last_gc(_old_evac_stats.allocated() * HeapWordSize);
 
   _gc_tracer_stw->report_evacuation_statistics(create_g1_evac_summary(&_survivor_evac_stats),
                                                create_g1_evac_summary(&_old_evac_stats));
@@ -4193,7 +4195,7 @@ class G1FreeCollectionSetTask : public AbstractGangTask {
       g1h->alloc_buffer_stats(G1HeapRegionAttr::Old)->add_failure_used_and_waste(_failure_used_words, _failure_waste_words);
 
       G1Policy *policy = g1h->policy();
-      policy->add_bytes_allocated_in_old_since_last_gc(_bytes_allocated_in_old_since_last_gc);
+      policy->old_gen_alloc_tracker()->add_allocated_bytes_since_last_gc(_bytes_allocated_in_old_since_last_gc);
       policy->record_rs_length(_rs_length);
       policy->cset_regions_freed();
     }

src/hotspot/share/gc/g1/g1OldGenAllocationTracker.cpp

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2020, Amazon.com, Inc. or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "gc/g1/g1OldGenAllocationTracker.hpp"
+
+G1OldGenAllocationTracker::G1OldGenAllocationTracker() :
+  _last_cycle_old_bytes(0),
+  _last_cycle_duration(0.0),
+  _allocated_bytes_since_last_gc(0) {
+}
+
+void G1OldGenAllocationTracker::reset_after_full_gc() {
+  _last_cycle_duration = 0;
+  reset_cycle_after_gc();
+}
+
+void G1OldGenAllocationTracker::reset_after_young_gc(double allocation_duration_s) {
+  _last_cycle_duration = allocation_duration_s;
+  reset_cycle_after_gc();
+}

src/hotspot/share/gc/g1/g1OldGenAllocationTracker.hpp

@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) 2020, Amazon.com, Inc. or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_VM_GC_G1_G1OLDGENALLOCATIONTRACKER_HPP
+#define SHARE_VM_GC_G1_G1OLDGENALLOCATIONTRACKER_HPP
+
+#include "gc/g1/heapRegion.hpp"
+#include "memory/allocation.hpp"
+
+// 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.
+  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 _allocated_bytes_since_last_gc;
+
+  void reset_cycle_after_gc() {
+    _last_cycle_old_bytes = _allocated_bytes_since_last_gc;
+    _allocated_bytes_since_last_gc = 0;
+  }
+
+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; }
+
+  double last_cycle_duration() { return _last_cycle_duration; }
+
+  // Reset stats after a collection.
+  void reset_after_full_gc();
+  void reset_after_young_gc(double allocation_duration_s);
+};
+
+#endif // SHARE_VM_GC_G1_G1OLDGENALLOCATIONTRACKER_HPP

src/hotspot/share/gc/g1/g1Policy.cpp

@@ -73,7 +73,7 @@ G1Policy::G1Policy(STWGCTimer* gc_timer) :
   _rs_length(0),
   _rs_length_prediction(0),
   _pending_cards_at_gc_start(0),
-  _bytes_allocated_in_old_since_last_gc(0),
+  _old_gen_alloc_tracker(),
   _initial_mark_to_mixed(),
   _collection_set(NULL),
   _g1h(NULL),
@@ -460,7 +460,7 @@ void G1Policy::record_full_collection_end() {
   update_young_list_max_and_target_length();
   update_rs_length_prediction();
 
-  _bytes_allocated_in_old_since_last_gc = 0;
+  _old_gen_alloc_tracker.reset_after_full_gc();
 
   record_pause(FullGC, _full_collection_start_sec, end_sec);
 }
@@ -795,11 +795,11 @@ void G1Policy::record_collection_pause_end(double pause_time_ms) {
     // predicted target occupancy.
     size_t last_unrestrained_young_length = update_young_list_max_and_target_length();
 
-    update_ihop_prediction(app_time_ms / 1000.0,
-                           _bytes_allocated_in_old_since_last_gc,
+    _old_gen_alloc_tracker.reset_after_young_gc(app_time_ms / 1000.0);
+    update_ihop_prediction(_old_gen_alloc_tracker.last_cycle_duration(),
+                           _old_gen_alloc_tracker.last_cycle_old_bytes(),
                            last_unrestrained_young_length * HeapRegion::GrainBytes,
                            this_pause_was_young_only);
-    _bytes_allocated_in_old_since_last_gc = 0;
 
     _ihop_control->send_trace_event(_g1h->gc_tracer_stw());
   } else {

src/hotspot/share/gc/g1/g1Policy.hpp

@@ -30,6 +30,7 @@
 #include "gc/g1/g1HeapRegionAttr.hpp"
 #include "gc/g1/g1InitialMarkToMixedTimeTracker.hpp"
 #include "gc/g1/g1MMUTracker.hpp"
+#include "gc/g1/g1OldGenAllocationTracker.hpp"
 #include "gc/g1/g1RemSetTrackingPolicy.hpp"
 #include "gc/g1/g1Predictions.hpp"
 #include "gc/g1/g1YoungGenSizer.hpp"
@@ -102,9 +103,9 @@ class G1Policy: public CHeapObj<mtGC> {
 
   size_t _pending_cards_at_gc_start;
 
-  // The amount of allocated bytes in old gen during the last mutator and the following
-  // young GC phase.
-  size_t _bytes_allocated_in_old_since_last_gc;
+  // Tracking the allocation in the old generation between
+  // two GCs.
+  G1OldGenAllocationTracker _old_gen_alloc_tracker;
 
   G1InitialMarkToMixedTimeTracker _initial_mark_to_mixed;
 
@@ -119,8 +120,7 @@ class G1Policy: public CHeapObj<mtGC> {
 
   G1RemSetTrackingPolicy* remset_tracker() { return &_remset_tracker; }
 
-  // Add the given number of bytes to the total number of allocated bytes in the old gen.
-  void add_bytes_allocated_in_old_since_last_gc(size_t bytes) { _bytes_allocated_in_old_since_last_gc += bytes; }
+  G1OldGenAllocationTracker* old_gen_alloc_tracker() { return &_old_gen_alloc_tracker; }
 
   void set_region_eden(HeapRegion* hr) {
     hr->set_eden();