diff -r 455328d90876 -r abdfc822206f src/share/vm/gc_implementation/g1/g1AllocRegion.hpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/gc_implementation/g1/g1AllocRegion.hpp	Wed Mar 30 10:26:59 2011 -0400
@@ -0,0 +1,174 @@
+/*
+ * Copyright (c) 2011, 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_IMPLEMENTATION_G1_G1ALLOCREGION_HPP
+#define SHARE_VM_GC_IMPLEMENTATION_G1_G1ALLOCREGION_HPP
+
+#include "gc_implementation/g1/heapRegion.hpp"
+
+class G1CollectedHeap;
+
+// 0 -> no tracing, 1 -> basic tracing, 2 -> basic + allocation tracing
+#define G1_ALLOC_REGION_TRACING 0
+
+class ar_ext_msg;
+
+// A class that holds a region that is active in satisfying allocation
+// requests, potentially issued in parallel. When the active region is
+// full it will be retired it replaced with a new one. The
+// implementation assumes that fast-path allocations will be lock-free
+// and a lock will need to be taken when the active region needs to be
+// replaced.
+
+class G1AllocRegion VALUE_OBJ_CLASS_SPEC {
+  friend class ar_ext_msg;
+
+private:
+  // The active allocating region we are currently allocating out
+  // of. The invariant is that if this object is initialized (i.e.,
+  // init() has been called and release() has not) then _alloc_region
+  // is either an active allocating region or the dummy region (i.e.,
+  // it can never be NULL) and this object can be used to satisfy
+  // allocation requests. If this object is not initialized
+  // (i.e. init() has not been called or release() has been called)
+  // then _alloc_region is NULL and this object should not be used to
+  // satisfy allocation requests (it was done this way to force the
+  // correct use of init() and release()).
+  HeapRegion* _alloc_region;
+
+  // When we set up a new active region we save its used bytes in this
+  // field so that, when we retire it, we can calculate how much space
+  // we allocated in it.
+  size_t _used_bytes_before;
+
+  // Specifies whether the allocate calls will do BOT updates or not.
+  bool _bot_updates;
+
+  // Useful for debugging and tracing.
+  const char* _name;
+
+  // A dummy region (i.e., it's been allocated specially for this
+  // purpose and it is not part of the heap) that is full (i.e., top()
+  // == end()). When we don't have a valid active region we make
+  // _alloc_region point to this. This allows us to skip checking
+  // whether the _alloc_region is NULL or not.
+  static HeapRegion* _dummy_region;
+
+  // Some of the methods below take a bot_updates parameter. Its value
+  // should be the same as the _bot_updates field. The idea is that
+  // the parameter will be a constant for a particular alloc region
+  // and, given that these methods will be hopefully inlined, the
+  // compiler should compile out the test.
+
+  // Perform a non-MT-safe allocation out of the given region.
+  static inline HeapWord* allocate(HeapRegion* alloc_region,
+                                   size_t word_size,
+                                   bool bot_updates);
+
+  // Perform a MT-safe allocation out of the given region.
+  static inline HeapWord* par_allocate(HeapRegion* alloc_region,
+                                       size_t word_size,
+                                       bool bot_updates);
+
+  // Ensure that the region passed as a parameter has been filled up
+  // so that noone else can allocate out of it any more.
+  static void fill_up_remaining_space(HeapRegion* alloc_region,
+                                      bool bot_updates);
+
+  // Retire the active allocating region. If fill_up is true then make
+  // sure that the region is full before we retire it so that noone
+  // else can allocate out of it.
+  void retire(bool fill_up);
+
+  // Allocate a new active region and use it to perform a word_size
+  // allocation. The force parameter will be passed on to
+  // G1CollectedHeap::allocate_new_alloc_region() and tells it to try
+  // to allocate a new region even if the max has been reached.
+  HeapWord* new_alloc_region_and_allocate(size_t word_size, bool force);
+
+  void fill_in_ext_msg(ar_ext_msg* msg, const char* message);
+
+protected:
+  // For convenience as subclasses use it.
+  static G1CollectedHeap* _g1h;
+
+  virtual HeapRegion* allocate_new_region(size_t word_size, bool force) = 0;
+  virtual void retire_region(HeapRegion* alloc_region,
+                             size_t allocated_bytes) = 0;
+
+  G1AllocRegion(const char* name, bool bot_updates);
+
+public:
+  static void setup(G1CollectedHeap* g1h, HeapRegion* dummy_region);
+
+  HeapRegion* get() const {
+    // Make sure that the dummy region does not escape this class.
+    return (_alloc_region == _dummy_region) ? NULL : _alloc_region;
+  }
+
+  // The following two are the building blocks for the allocation method.
+
+  // First-level allocation: Should be called without holding a
+  // lock. It will try to allocate lock-free out of the active region,
+  // or return NULL if it was unable to.
+  inline HeapWord* attempt_allocation(size_t word_size, bool bot_updates);
+
+  // Second-level allocation: Should be called while holding a
+  // lock. It will try to first allocate lock-free out of the active
+  // region or, if it's unable to, it will try to replace the active
+  // alloc region with a new one. We require that the caller takes the
+  // appropriate lock before calling this so that it is easier to make
+  // it conform to its locking protocol.
+  inline HeapWord* attempt_allocation_locked(size_t word_size,
+                                             bool bot_updates);
+
+  // Should be called to allocate a new region even if the max of this
+  // type of regions has been reached. Should only be called if other
+  // allocation attempts have failed and we are not holding a valid
+  // active region.
+  inline HeapWord* attempt_allocation_force(size_t word_size,
+                                            bool bot_updates);
+
+  // Should be called before we start using this object.
+  void init();
+
+  // Should be called when we want to release the active region which
+  // is returned after it's been retired.
+  HeapRegion* release();
+
+#if G1_ALLOC_REGION_TRACING
+  void trace(const char* str, size_t word_size = 0, HeapWord* result = NULL);
+#else // G1_ALLOC_REGION_TRACING
+  void trace(const char* str, size_t word_size = 0, HeapWord* result = NULL) { }
+#endif // G1_ALLOC_REGION_TRACING
+};
+
+class ar_ext_msg : public err_msg {
+public:
+  ar_ext_msg(G1AllocRegion* alloc_region, const char *message) : err_msg("") {
+    alloc_region->fill_in_ext_msg(this, message);
+  }
+};
+
+#endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1ALLOCREGION_HPP