8151178: Move the collection set out of the G1 collector policy

Create a G1CollectionSet class

Reviewed-by: jwilhelm, tbenson, tschatzl

hotspot/src/share/vm/gc/g1/g1CollectionSet.hpp

@@ -0,0 +1,207 @@
+/*
+ * Copyright (c) 2016, 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.
+ *
+ * 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_G1COLLECTIONSET_HPP
+#define SHARE_VM_GC_G1_G1COLLECTIONSET_HPP
+
+#include "gc/g1/collectionSetChooser.hpp"
+#include "memory/allocation.hpp"
+#include "utilities/debug.hpp"
+#include "utilities/globalDefinitions.hpp"
+
+class G1CollectedHeap;
+class G1CollectorPolicy;
+class G1CollectorState;
+class G1GCPhaseTimes;
+class HeapRegion;
+
+class G1CollectionSet VALUE_OBJ_CLASS_SPEC {
+  G1CollectedHeap* _g1;
+  G1CollectorPolicy* _policy;
+
+  CollectionSetChooser* _cset_chooser;
+
+  uint _eden_region_length;
+  uint _survivor_region_length;
+  uint _old_region_length;
+
+  // The head of the list (via "next_in_collection_set()") representing the
+  // current collection set. Set from the incrementally built collection
+  // set at the start of the pause.
+  HeapRegion* _head;
+
+  // The number of bytes in the collection set before the pause. Set from
+  // the incrementally built collection set at the start of an evacuation
+  // pause, and incremented in finalize_old_part() when adding old regions
+  // (if any) to the collection set.
+  size_t _bytes_used_before;
+
+  size_t _recorded_rs_lengths;
+
+  // The associated information that is maintained while the incremental
+  // collection set is being built with young regions. Used to populate
+  // the recorded info for the evacuation pause.
+
+  enum CSetBuildType {
+    Active,             // We are actively building the collection set
+    Inactive            // We are not actively building the collection set
+  };
+
+  CSetBuildType _inc_build_state;
+
+  // The head of the incrementally built collection set.
+  HeapRegion* _inc_head;
+
+  // The tail of the incrementally built collection set.
+  HeapRegion* _inc_tail;
+
+  // The number of bytes in the incrementally built collection set.
+  // Used to set _collection_set_bytes_used_before at the start of
+  // an evacuation pause.
+  size_t _inc_bytes_used_before;
+
+  // The RSet lengths recorded for regions in the CSet. It is updated
+  // by the thread that adds a new region to the CSet. We assume that
+  // only one thread can be allocating a new CSet region (currently,
+  // it does so after taking the Heap_lock) hence no need to
+  // synchronize updates to this field.
+  size_t _inc_recorded_rs_lengths;
+
+  // A concurrent refinement thread periodically samples the young
+  // region RSets and needs to update _inc_recorded_rs_lengths as
+  // the RSets grow. Instead of having to synchronize updates to that
+  // field we accumulate them in this field and add it to
+  // _inc_recorded_rs_lengths_diffs at the start of a GC.
+  ssize_t _inc_recorded_rs_lengths_diffs;
+
+  // The predicted elapsed time it will take to collect the regions in
+  // the CSet. This is updated by the thread that adds a new region to
+  // the CSet. See the comment for _inc_recorded_rs_lengths about
+  // MT-safety assumptions.
+  double _inc_predicted_elapsed_time_ms;
+
+  // See the comment for _inc_recorded_rs_lengths_diffs.
+  double _inc_predicted_elapsed_time_ms_diffs;
+
+  G1CollectorState* collector_state();
+  G1GCPhaseTimes* phase_times();
+
+  double predict_region_elapsed_time_ms(HeapRegion* hr);
+
+public:
+  G1CollectionSet(G1CollectedHeap* g1h);
+  ~G1CollectionSet();
+
+  void set_policy(G1CollectorPolicy* g1p) {
+    assert(_policy == NULL, "should only initialize once");
+    _policy = g1p;
+  }
+
+  CollectionSetChooser* cset_chooser();
+
+  void init_region_lengths(uint eden_cset_region_length,
+                           uint survivor_cset_region_length);
+
+  void set_recorded_rs_lengths(size_t rs_lengths);
+
+  uint region_length() const       { return young_region_length() +
+                                            old_region_length(); }
+  uint young_region_length() const { return eden_region_length() +
+                                            survivor_region_length(); }
+
+  uint eden_region_length() const     { return _eden_region_length;     }
+  uint survivor_region_length() const { return _survivor_region_length; }
+  uint old_region_length() const      { return _old_region_length;      }
+
+  // Incremental CSet Support
+
+  // The head of the incrementally built collection set.
+  HeapRegion* inc_head() { return _inc_head; }
+
+  // The tail of the incrementally built collection set.
+  HeapRegion* inc_tail() { return _inc_tail; }
+
+  // Initialize incremental collection set info.
+  void start_incremental_building();
+
+  // Perform any final calculations on the incremental CSet fields
+  // before we can use them.
+  void finalize_incremental_building();
+
+  void clear_incremental() {
+    _inc_head = NULL;
+    _inc_tail = NULL;
+  }
+
+  // Stop adding regions to the incremental collection set
+  void stop_incremental_building() { _inc_build_state = Inactive; }
+
+  // The head of the list (via "next_in_collection_set()") representing the
+  // current collection set.
+  HeapRegion* head() { return _head; }
+
+  void clear_head() { _head = NULL; }
+
+  size_t recorded_rs_lengths() { return _recorded_rs_lengths; }
+
+  size_t bytes_used_before() const {
+    return _bytes_used_before;
+  }
+
+  void reset_bytes_used_before() {
+    _bytes_used_before = 0;
+  }
+
+  // Choose a new collection set.  Marks the chosen regions as being
+  // "in_collection_set", and links them together.  The head and number of
+  // the collection set are available via access methods.
+  double finalize_young_part(double target_pause_time_ms);
+  void finalize_old_part(double time_remaining_ms);
+
+  // Add old region "hr" to the CSet.
+  void add_old_region(HeapRegion* hr);
+
+  // Update information about hr in the aggregated information for
+  // the incrementally built collection set.
+  void update_young_region_prediction(HeapRegion* hr, size_t new_rs_length);
+
+  // Add hr to the LHS of the incremental collection set.
+  void add_eden_region(HeapRegion* hr);
+
+  // Add hr to the RHS of the incremental collection set.
+  void add_survivor_regions(HeapRegion* hr);
+
+#ifndef PRODUCT
+  void print(HeapRegion* list_head, outputStream* st);
+#endif // !PRODUCT
+
+private:
+  // Update the incremental cset information when adding a region
+  // (should not be called directly).
+  void add_young_region_common(HeapRegion* hr);
+
+};
+
+#endif // SHARE_VM_GC_G1_G1COLLECTIONSET_HPP
+