--- /dev/null	2020-01-17 11:46:19.065201212 +0100
+++ new/src/hotspot/share/gc/shenandoah/heuristics/shenandoahTraversalAggressiveHeuristics.cpp	2020-01-17 17:09:45.021131862 +0100
@@ -0,0 +1,130 @@
+/*
+ * Copyright (c) 2018, 2019, Red Hat, Inc. All rights reserved.
+ *
+ * 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/shenandoah/heuristics/shenandoahTraversalAggressiveHeuristics.hpp"
+#include "gc/shenandoah/shenandoahCollectionSet.hpp"
+#include "gc/shenandoah/shenandoahFreeSet.hpp"
+#include "gc/shenandoah/shenandoahHeap.inline.hpp"
+#include "gc/shenandoah/shenandoahHeuristics.hpp"
+#include "gc/shenandoah/shenandoahTraversalGC.hpp"
+#include "logging/log.hpp"
+#include "logging/logTag.hpp"
+#include "utilities/quickSort.hpp"
+
+ShenandoahTraversalAggressiveHeuristics::ShenandoahTraversalAggressiveHeuristics() : ShenandoahHeuristics(),
+  _last_cset_select(0) {
+  // Do not shortcut evacuation
+  SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahImmediateThreshold, 100);
+
+  // Aggressive runs with max speed for allocation, to capture races against mutator
+  SHENANDOAH_ERGO_DISABLE_FLAG(ShenandoahPacing);
+
+  // Aggressive evacuates everything, so it needs as much evac space as it can get
+  SHENANDOAH_ERGO_ENABLE_FLAG(ShenandoahEvacReserveOverflow);
+
+  // If class unloading is globally enabled, aggressive does unloading even with
+  // concurrent cycles.
+  if (ClassUnloading) {
+    SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahUnloadClassesFrequency, 1);
+  }
+
+}
+
+bool ShenandoahTraversalAggressiveHeuristics::is_experimental() {
+  return false;
+}
+
+bool ShenandoahTraversalAggressiveHeuristics::is_diagnostic() {
+  return true;
+}
+
+const char* ShenandoahTraversalAggressiveHeuristics::name() {
+  return "traversal-aggressive";
+}
+
+void ShenandoahTraversalAggressiveHeuristics::choose_collection_set(ShenandoahCollectionSet* collection_set) {
+  ShenandoahHeap* heap = ShenandoahHeap::heap();
+
+  ShenandoahTraversalGC* traversal_gc = heap->traversal_gc();
+
+  ShenandoahHeapRegionSet* traversal_set = traversal_gc->traversal_set();
+  traversal_set->clear();
+
+  RegionData *data = get_region_data_cache(heap->num_regions());
+  size_t cnt = 0;
+
+  // About to choose the collection set, make sure we have pinned regions in correct state
+  heap->assert_pinned_region_status();
+
+  // Step 0. Prepare all regions
+  for (size_t i = 0; i < heap->num_regions(); i++) {
+    ShenandoahHeapRegion* r = heap->get_region(i);
+    if (r->used() > 0) {
+      if (r->is_regular()) {
+        data[cnt]._region = r;
+        data[cnt]._garbage = r->garbage();
+        data[cnt]._seqnum_last_alloc = r->seqnum_last_alloc_mutator();
+        cnt++;
+      }
+      traversal_set->add_region(r);
+    }
+  }
+
+  for (size_t i = 0; i < cnt; i++) {
+    if (data[i]._seqnum_last_alloc > _last_cset_select) continue;
+
+    ShenandoahHeapRegion* r = data[i]._region;
+    assert (r->is_regular(), "should have been filtered before");
+
+   if (r->garbage() > 0) {
+      assert(!collection_set->is_in(r), "must not yet be in cset");
+      collection_set->add_region(r);
+    }
+  }
+
+  // Clear liveness data
+  // TODO: Merge it with step 0, but save live data in RegionData before.
+  for (size_t i = 0; i < heap->num_regions(); i++) {
+    ShenandoahHeapRegion* r = heap->get_region(i);
+    if (r->used() > 0) {
+      r->clear_live_data();
+    }
+  }
+
+  collection_set->update_region_status();
+
+  _last_cset_select = ShenandoahHeapRegion::seqnum_current_alloc();
+}
+
+void ShenandoahTraversalAggressiveHeuristics::choose_collection_set_from_regiondata(ShenandoahCollectionSet* set,
+                                                                                    RegionData* data, size_t data_size,
+                                                                                    size_t free) {
+  ShouldNotReachHere();
+}
+
+bool ShenandoahTraversalAggressiveHeuristics::should_start_gc() const {
+  log_info(gc)("Trigger: Start next cycle immediately");
+  return true;
+}