src/share/vm/jfr/leakprofiler/chains/bfsClosure.cpp

rev 9055 : 8214542: JFR: Old Object Sample event slow on a deep heap in debug builds
Reviewed-by: egahlin, rwestberg
rev 9057 : 8229437: assert(is_aligned(ref, HeapWordSize)) failed: invariant
Reviewed-by: egahlin

@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 2014, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, 2019, Oracle and/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.

@@ -95,11 +95,10 @@
       (nof_dfs_completed_edges * edge_size) / K
                         );
 }
 
 void BFSClosure::process() {
-
   process_root_set();
   process_queue();
 }
 
 void BFSClosure::process_root_set() {

@@ -134,11 +133,10 @@
       add_chain(reference, pointee);
     }
 
     // if we are processinig initial root set, don't add to queue
     if (_current_parent != NULL) {
-      assert(_current_parent->distance_to_root() == _current_frontier_level, "invariant");
       _edge_queue->add(_current_parent, reference);
     }
 
     if (_edge_queue->is_full()) {
       dfs_fallback();

@@ -147,24 +145,12 @@
 }
 
 void BFSClosure::add_chain(const oop* reference, const oop pointee) {
   assert(pointee != NULL, "invariant");
   assert(NULL == pointee->mark(), "invariant");
-
-  const size_t length = _current_parent == NULL ? 1 : _current_parent->distance_to_root() + 2;
-  ResourceMark rm;
-  Edge* const chain = NEW_RESOURCE_ARRAY(Edge, length);
-  size_t idx = 0;
-  chain[idx++] = Edge(NULL, reference);
-  // aggregate from breadth-first search
-  const Edge* current = _current_parent;
-  while (current != NULL) {
-    chain[idx++] = Edge(NULL, current->reference());
-    current = current->parent();
-  }
-  assert(length == idx, "invariant");
-  _edge_store->add_chain(chain, length);
+  Edge leak_edge(_current_parent, reference);
+  _edge_store->put_chain(&leak_edge, _current_parent == NULL ? 1 : _current_frontier_level + 2);
 }
 
 void BFSClosure::dfs_fallback() {
   assert(_edge_queue->is_full(), "invariant");
   _use_dfs = true;

@@ -237,5 +223,12 @@
   const oop pointee = oopDesc::load_decode_heap_oop(ref);
   if (pointee != NULL) {
     closure_impl(UnifiedOop::encode(ref), pointee);
   }
 }
+
+void BFSClosure::do_root(const oop* ref) {
+  assert(ref != NULL, "invariant");
+  if (!_edge_queue->is_full()) {
+    _edge_queue->add(NULL, ref);
+  }
+}