src/hotspot/share/gc/g1/heapRegionSet.hpp
changeset 47216 71c04702a3d5
parent 35065 b4ff0249c092
child 49392 2956d0ece7a9
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/g1/heapRegionSet.hpp	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,258 @@
+/*
+ * Copyright (c) 2011, 2015, 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_HEAPREGIONSET_HPP
+#define SHARE_VM_GC_G1_HEAPREGIONSET_HPP
+
+#include "gc/g1/heapRegion.hpp"
+
+#define assert_heap_region_set(p, message) \
+  do {                                     \
+    assert((p), "[%s] %s ln: %u",          \
+           name(), message, length());     \
+  } while (0)
+
+#define guarantee_heap_region_set(p, message) \
+  do {                                        \
+    guarantee((p), "[%s] %s ln: %u",          \
+              name(), message, length());     \
+  } while (0)
+
+#define assert_free_region_list(p, message)                          \
+  do {                                                               \
+    assert((p), "[%s] %s ln: %u hd: " PTR_FORMAT " tl: " PTR_FORMAT, \
+           name(), message, length(), p2i(_head), p2i(_tail));       \
+  } while (0)
+
+
+// Set verification will be forced either if someone defines
+// HEAP_REGION_SET_FORCE_VERIFY to be 1, or in builds in which
+// asserts are compiled in.
+#ifndef HEAP_REGION_SET_FORCE_VERIFY
+#define HEAP_REGION_SET_FORCE_VERIFY defined(ASSERT)
+#endif // HEAP_REGION_SET_FORCE_VERIFY
+
+class HRSMtSafeChecker : public CHeapObj<mtGC> {
+public:
+  virtual void check() = 0;
+};
+
+class MasterFreeRegionListMtSafeChecker    : public HRSMtSafeChecker { public: void check(); };
+class SecondaryFreeRegionListMtSafeChecker : public HRSMtSafeChecker { public: void check(); };
+class HumongousRegionSetMtSafeChecker      : public HRSMtSafeChecker { public: void check(); };
+class OldRegionSetMtSafeChecker            : public HRSMtSafeChecker { public: void check(); };
+
+// Base class for all the classes that represent heap region sets. It
+// contains the basic attributes that each set needs to maintain
+// (e.g., length, region num, used bytes sum) plus any shared
+// functionality (e.g., verification).
+
+class HeapRegionSetBase VALUE_OBJ_CLASS_SPEC {
+  friend class VMStructs;
+private:
+  bool _is_humongous;
+  bool _is_free;
+  HRSMtSafeChecker* _mt_safety_checker;
+
+protected:
+  // The number of regions in to the set.
+  uint _length;
+
+  const char* _name;
+
+  bool _verify_in_progress;
+
+  // verify_region() is used to ensure that the contents of a region
+  // added to / removed from a set are consistent.
+  void verify_region(HeapRegion* hr) PRODUCT_RETURN;
+
+  // Indicates whether all regions in the set should be humongous or
+  // not. Only used during verification.
+  bool regions_humongous() { return _is_humongous; }
+
+  // Indicates whether all regions in the set should be free or
+  // not. Only used during verification.
+  bool regions_free() { return _is_free; }
+
+  void check_mt_safety() {
+    if (_mt_safety_checker != NULL) {
+      _mt_safety_checker->check();
+    }
+  }
+
+  HeapRegionSetBase(const char* name, bool humongous, bool free, HRSMtSafeChecker* mt_safety_checker);
+
+public:
+  const char* name() { return _name; }
+
+  uint length() const { return _length; }
+
+  bool is_empty() { return _length == 0; }
+
+  // It updates the fields of the set to reflect hr being added to
+  // the set and tags the region appropriately.
+  inline void add(HeapRegion* hr);
+
+  // It updates the fields of the set to reflect hr being removed
+  // from the set and tags the region appropriately.
+  inline void remove(HeapRegion* hr);
+
+  virtual void verify();
+  void verify_start();
+  void verify_next_region(HeapRegion* hr);
+  void verify_end();
+
+#if HEAP_REGION_SET_FORCE_VERIFY
+  void verify_optional() {
+    verify();
+  }
+#else // HEAP_REGION_SET_FORCE_VERIFY
+  void verify_optional() { }
+#endif // HEAP_REGION_SET_FORCE_VERIFY
+
+  virtual void print_on(outputStream* out, bool print_contents = false);
+};
+
+#define hrs_assert_sets_match(_set1_, _set2_)                                  \
+  do {                                                                         \
+    assert(((_set1_)->regions_humongous() == (_set2_)->regions_humongous()) && \
+           ((_set1_)->regions_free() == (_set2_)->regions_free()),             \
+           "the contents of set %s and set %s should match",                   \
+           (_set1_)->name(),                                                   \
+           (_set2_)->name());                                                  \
+  } while (0)
+
+// This class represents heap region sets whose members are not
+// explicitly tracked. It's helpful to group regions using such sets
+// so that we can reason about all the region groups in the heap using
+// the same interface (namely, the HeapRegionSetBase API).
+
+class HeapRegionSet : public HeapRegionSetBase {
+public:
+  HeapRegionSet(const char* name, bool humongous, HRSMtSafeChecker* mt_safety_checker):
+    HeapRegionSetBase(name, humongous, false /* free */, mt_safety_checker) { }
+
+  void bulk_remove(const uint removed) {
+    _length -= removed;
+  }
+};
+
+// A set that links all the regions added to it in a doubly-linked
+// sorted list. We should try to avoid doing operations that iterate over
+// such lists in performance critical paths. Typically we should
+// add / remove one region at a time or concatenate two lists.
+
+class FreeRegionListIterator;
+
+class FreeRegionList : public HeapRegionSetBase {
+  friend class FreeRegionListIterator;
+
+private:
+  HeapRegion* _head;
+  HeapRegion* _tail;
+
+  // _last is used to keep track of where we added an element the last
+  // time. It helps to improve performance when adding several ordered items in a row.
+  HeapRegion* _last;
+
+  static uint _unrealistically_long_length;
+
+  inline HeapRegion* remove_from_head_impl();
+  inline HeapRegion* remove_from_tail_impl();
+
+protected:
+  // See the comment for HeapRegionSetBase::clear()
+  virtual void clear();
+
+public:
+  FreeRegionList(const char* name, HRSMtSafeChecker* mt_safety_checker = NULL):
+    HeapRegionSetBase(name, false /* humongous */, true /* empty */, mt_safety_checker) {
+    clear();
+  }
+
+  void verify_list();
+
+#ifdef ASSERT
+  bool contains(HeapRegion* hr) const {
+    return hr->containing_set() == this;
+  }
+#endif
+
+  static void set_unrealistically_long_length(uint len);
+
+  // Add hr to the list. The region should not be a member of another set.
+  // Assumes that the list is ordered and will preserve that order. The order
+  // is determined by hrm_index.
+  inline void add_ordered(HeapRegion* hr);
+
+  // Removes from head or tail based on the given argument.
+  HeapRegion* remove_region(bool from_head);
+
+  // Merge two ordered lists. The result is also ordered. The order is
+  // determined by hrm_index.
+  void add_ordered(FreeRegionList* from_list);
+
+  // It empties the list by removing all regions from it.
+  void remove_all();
+
+  // Remove all (contiguous) regions from first to first + num_regions -1 from
+  // this list.
+  // Num_regions must be > 1.
+  void remove_starting_at(HeapRegion* first, uint num_regions);
+
+  virtual void verify();
+};
+
+// Iterator class that provides a convenient way to iterate over the
+// regions of a FreeRegionList.
+
+class FreeRegionListIterator : public StackObj {
+private:
+  FreeRegionList* _list;
+  HeapRegion*     _curr;
+
+public:
+  bool more_available() {
+    return _curr != NULL;
+  }
+
+  HeapRegion* get_next() {
+    assert(more_available(),
+           "get_next() should be called when more regions are available");
+
+    // If we are going to introduce a count in the iterator we should
+    // do the "cycle" check.
+
+    HeapRegion* hr = _curr;
+    _list->verify_region(hr);
+    _curr = hr->next();
+    return hr;
+  }
+
+  FreeRegionListIterator(FreeRegionList* list) : _curr(NULL), _list(list) {
+    _curr = list->_head;
+  }
+};
+
+#endif // SHARE_VM_GC_G1_HEAPREGIONSET_HPP