8057536: Refactor G1 to allow context specific allocations

Summary: Splitting out a g1 allocator class to simply specialized allocators which can associate each allocation with a given context.
Reviewed-by: mgerdin, brutisso

agent/src/share/classes/sun/jvm/hotspot/gc_implementation/g1/G1Allocator.java

+package sun.jvm.hotspot.gc_implementation.g1;
+
+import java.util.Observable;
+import java.util.Observer;
+
+import sun.jvm.hotspot.debugger.Address;
+import sun.jvm.hotspot.runtime.VM;
+import sun.jvm.hotspot.runtime.VMObject;
+import sun.jvm.hotspot.types.CIntegerField;
+import sun.jvm.hotspot.types.Type;
+import sun.jvm.hotspot.types.TypeDataBase;
+
+public class G1Allocator extends VMObject {
+
+  //size_t _summary_bytes_used;
+  static private CIntegerField summaryBytesUsedField;
+
+  static {
+    VM.registerVMInitializedObserver(new Observer() {
+      public void update(Observable o, Object data) {
+        initialize(VM.getVM().getTypeDataBase());
+      }
+    });
+  }
+
+  static private synchronized void initialize(TypeDataBase db) {
+    Type type = db.lookupType("G1Allocator");
+
+    summaryBytesUsedField = type.getCIntegerField("_summary_bytes_used");
+  }
+
+  public long getSummaryBytes() {
+    return summaryBytesUsedField.getValue(addr);
+  }
+
+  public G1Allocator(Address addr) {
+    super(addr);
+
+  }
+}

agent/src/share/classes/sun/jvm/hotspot/gc_implementation/g1/G1CollectedHeap.java

@@ -36,7 +36,6 @@ import sun.jvm.hotspot.memory.SpaceClosure;
 import sun.jvm.hotspot.runtime.VM;
 import sun.jvm.hotspot.runtime.VMObjectFactory;
 import sun.jvm.hotspot.types.AddressField;
-import sun.jvm.hotspot.types.CIntegerField;
 import sun.jvm.hotspot.types.Type;
 import sun.jvm.hotspot.types.TypeDataBase;
 
@@ -47,8 +46,8 @@ public class G1CollectedHeap extends SharedHeap {
     static private long hrmFieldOffset;
     // MemRegion _g1_reserved;
     static private long g1ReservedFieldOffset;
-    // size_t _summary_bytes_used;
-    static private CIntegerField summaryBytesUsedField;
+    // G1Allocator* _allocator
+    static private AddressField g1Allocator;
     // G1MonitoringSupport* _g1mm;
     static private AddressField g1mmField;
     // HeapRegionSet _old_set;
@@ -68,7 +67,7 @@ public class G1CollectedHeap extends SharedHeap {
         Type type = db.lookupType("G1CollectedHeap");
 
         hrmFieldOffset = type.getField("_hrm").getOffset();
-        summaryBytesUsedField = type.getCIntegerField("_summary_bytes_used");
+        g1Allocator = type.getAddressField("_allocator");
         g1mmField = type.getAddressField("_g1mm");
         oldSetFieldOffset = type.getField("_old_set").getOffset();
         humongousSetFieldOffset = type.getField("_humongous_set").getOffset();
@@ -79,7 +78,7 @@ public class G1CollectedHeap extends SharedHeap {
     }
 
     public long used() {
-        return summaryBytesUsedField.getValue(addr);
+        return allocator().getSummaryBytes();
     }
 
     public long n_regions() {
@@ -97,6 +96,11 @@ public class G1CollectedHeap extends SharedHeap {
         return (G1MonitoringSupport) VMObjectFactory.newObject(G1MonitoringSupport.class, g1mmAddr);
     }
 
+    public G1Allocator allocator() {
+        Address g1AllocatorAddr = g1Allocator.getValue(addr);
+        return (G1Allocator) VMObjectFactory.newObject(G1Allocator.class, g1AllocatorAddr);
+    }
+
     public HeapRegionSetBase oldSet() {
         Address oldSetAddr = addr.addOffsetTo(oldSetFieldOffset);
         return (HeapRegionSetBase) VMObjectFactory.newObject(HeapRegionSetBase.class,

src/share/vm/gc_implementation/g1/g1AllocRegion.cpp

@@ -129,8 +129,7 @@ HeapWord* G1AllocRegion::new_alloc_region_and_allocate(size_t word_size,
     // Note that we first perform the allocation and then we store the
     // region in _alloc_region. This is the reason why an active region
     // can never be empty.
-    _alloc_region = new_alloc_region;
-    _count += 1;
+    update_alloc_region(new_alloc_region);
     trace("region allocation successful");
     return result;
   } else {
@@ -172,6 +171,19 @@ void G1AllocRegion::set(HeapRegion* alloc_region) {
   trace("set");
 }
 
+void G1AllocRegion::update_alloc_region(HeapRegion* alloc_region) {
+  trace("update");
+  // We explicitly check that the region is not empty to make sure we
+  // maintain the "the alloc region cannot be empty" invariant.
+  assert(alloc_region != NULL && !alloc_region->is_empty(),
+         ar_ext_msg(this, "pre-condition"));
+
+  _alloc_region = alloc_region;
+  _alloc_region->set_allocation_context(allocation_context());
+  _count += 1;
+  trace("updated");
+}
+
 HeapRegion* G1AllocRegion::release() {
   trace("releasing");
   HeapRegion* alloc_region = _alloc_region;
@@ -225,5 +237,70 @@ void G1AllocRegion::trace(const char* str, size_t word_size, HeapWord* result) {
 G1AllocRegion::G1AllocRegion(const char* name,
                              bool bot_updates)
   : _name(name), _bot_updates(bot_updates),
-    _alloc_region(NULL), _count(0), _used_bytes_before(0) { }
+    _alloc_region(NULL), _count(0), _used_bytes_before(0),
+    _allocation_context(AllocationContext::system()) { }
+
+
+HeapRegion* MutatorAllocRegion::allocate_new_region(size_t word_size,
+                                                    bool force) {
+  return _g1h->new_mutator_alloc_region(word_size, force);
+}
+
+void MutatorAllocRegion::retire_region(HeapRegion* alloc_region,
+                                       size_t allocated_bytes) {
+  _g1h->retire_mutator_alloc_region(alloc_region, allocated_bytes);
+}
+
+HeapRegion* SurvivorGCAllocRegion::allocate_new_region(size_t word_size,
+                                                       bool force) {
+  assert(!force, "not supported for GC alloc regions");
+  return _g1h->new_gc_alloc_region(word_size, count(), GCAllocForSurvived);
+}
+
+void SurvivorGCAllocRegion::retire_region(HeapRegion* alloc_region,
+                                          size_t allocated_bytes) {
+  _g1h->retire_gc_alloc_region(alloc_region, allocated_bytes,
+                               GCAllocForSurvived);
+}
+
+HeapRegion* OldGCAllocRegion::allocate_new_region(size_t word_size,
+                                                  bool force) {
+  assert(!force, "not supported for GC alloc regions");
+  return _g1h->new_gc_alloc_region(word_size, count(), GCAllocForTenured);
+}
+
+void OldGCAllocRegion::retire_region(HeapRegion* alloc_region,
+                                     size_t allocated_bytes) {
+  _g1h->retire_gc_alloc_region(alloc_region, allocated_bytes,
+                               GCAllocForTenured);
+}
+
+HeapRegion* OldGCAllocRegion::release() {
+  HeapRegion* cur = get();
+  if (cur != NULL) {
+    // Determine how far we are from the next card boundary. If it is smaller than
+    // the minimum object size we can allocate into, expand into the next card.
+    HeapWord* top = cur->top();
+    HeapWord* aligned_top = (HeapWord*)align_ptr_up(top, G1BlockOffsetSharedArray::N_bytes);
+
+    size_t to_allocate_words = pointer_delta(aligned_top, top, HeapWordSize);
+
+    if (to_allocate_words != 0) {
+      // We are not at a card boundary. Fill up, possibly into the next, taking the
+      // end of the region and the minimum object size into account.
+      to_allocate_words = MIN2(pointer_delta(cur->end(), cur->top(), HeapWordSize),
+                               MAX2(to_allocate_words, G1CollectedHeap::min_fill_size()));
+
+      // Skip allocation if there is not enough space to allocate even the smallest
+      // possible object. In this case this region will not be retained, so the
+      // original problem cannot occur.
+      if (to_allocate_words >= G1CollectedHeap::min_fill_size()) {
+        HeapWord* dummy = attempt_allocation(to_allocate_words, true /* bot_updates */);
+        CollectedHeap::fill_with_object(dummy, to_allocate_words);
+      }
+    }
+  }
+  return G1AllocRegion::release();
+}
+
 

src/share/vm/gc_implementation/g1/g1AllocRegion.hpp

@@ -57,6 +57,9 @@ private:
   // correct use of init() and release()).
   HeapRegion* volatile _alloc_region;
 
+  // Allocation context associated with this alloc region.
+  AllocationContext_t _allocation_context;
+
   // It keeps track of the distinct number of regions that are used
   // for allocation in the active interval of this object, i.e.,
   // between a call to init() and a call to release(). The count
@@ -110,6 +113,10 @@ private:
   // else can allocate out of it.
   void retire(bool fill_up);
 
+  // After a region is allocated by alloc_new_region, this
+  // method is used to set it as the active alloc_region
+  void update_alloc_region(HeapRegion* alloc_region);
+
   // 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
@@ -137,6 +144,9 @@ public:
     return (hr == _dummy_region) ? NULL : hr;
   }
 
+  void set_allocation_context(AllocationContext_t context) { _allocation_context = context; }
+  AllocationContext_t  allocation_context() { return _allocation_context; }
+
   uint count() { return _count; }
 
   // The following two are the building blocks for the allocation method.
@@ -182,6 +192,40 @@ public:
 #endif // G1_ALLOC_REGION_TRACING
 };
 
+class MutatorAllocRegion : public G1AllocRegion {
+protected:
+  virtual HeapRegion* allocate_new_region(size_t word_size, bool force);
+  virtual void retire_region(HeapRegion* alloc_region, size_t allocated_bytes);
+public:
+  MutatorAllocRegion()
+    : G1AllocRegion("Mutator Alloc Region", false /* bot_updates */) { }
+};
+
+class SurvivorGCAllocRegion : public G1AllocRegion {
+protected:
+  virtual HeapRegion* allocate_new_region(size_t word_size, bool force);
+  virtual void retire_region(HeapRegion* alloc_region, size_t allocated_bytes);
+public:
+  SurvivorGCAllocRegion()
+  : G1AllocRegion("Survivor GC Alloc Region", false /* bot_updates */) { }
+};
+
+class OldGCAllocRegion : public G1AllocRegion {
+protected:
+  virtual HeapRegion* allocate_new_region(size_t word_size, bool force);
+  virtual void retire_region(HeapRegion* alloc_region, size_t allocated_bytes);
+public:
+  OldGCAllocRegion()
+  : G1AllocRegion("Old GC Alloc Region", true /* bot_updates */) { }
+
+  // This specialization of release() makes sure that the last card that has
+  // been allocated into has been completely filled by a dummy object.  This
+  // avoids races when remembered set scanning wants to update the BOT of the
+  // last card in the retained old gc alloc region, and allocation threads
+  // allocating into that card at the same time.
+  virtual HeapRegion* release();
+};
+
 class ar_ext_msg : public err_msg {
 public:
   ar_ext_msg(G1AllocRegion* alloc_region, const char *message) : err_msg("%s", "") {

src/share/vm/gc_implementation/g1/g1AllocationContext.hpp

+/*
+ * Copyright (c) 2014, 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_G1ALLOCATIONCONTEXT_HPP
+#define SHARE_VM_GC_IMPLEMENTATION_G1_G1ALLOCATIONCONTEXT_HPP
+
+#include "memory/allocation.hpp"
+
+typedef unsigned char AllocationContext_t;
+
+class AllocationContext : AllStatic {
+public:
+  // Currently used context
+  static AllocationContext_t current() {
+    return 0;
+  }
+  // System wide default context
+  static AllocationContext_t system() {
+    return 0;
+  }
+};
+
+#endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1ALLOCATIONCONTEXT_HPP

src/share/vm/gc_implementation/g1/g1Allocator.cpp

+/*
+ * Copyright (c) 2014, 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.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "gc_implementation/g1/g1Allocator.hpp"
+#include "gc_implementation/g1/g1CollectedHeap.hpp"
+#include "gc_implementation/g1/g1CollectorPolicy.hpp"
+#include "gc_implementation/g1/heapRegion.inline.hpp"
+#include "gc_implementation/g1/heapRegionSet.inline.hpp"
+
+void G1DefaultAllocator::init_mutator_alloc_region() {
+  assert(_mutator_alloc_region.get() == NULL, "pre-condition");
+  _mutator_alloc_region.init();
+}
+
+void G1DefaultAllocator::release_mutator_alloc_region() {
+  _mutator_alloc_region.release();
+  assert(_mutator_alloc_region.get() == NULL, "post-condition");
+}
+
+void G1Allocator::reuse_retained_old_region(EvacuationInfo& evacuation_info,
+                                            OldGCAllocRegion* old,
+                                            HeapRegion** retained_old) {
+  HeapRegion* retained_region = *retained_old;
+  *retained_old = NULL;
+
+  // We will discard the current GC alloc region if:
+  // a) it's in the collection set (it can happen!),
+  // b) it's already full (no point in using it),
+  // c) it's empty (this means that it was emptied during
+  // a cleanup and it should be on the free list now), or
+  // d) it's humongous (this means that it was emptied
+  // during a cleanup and was added to the free list, but
+  // has been subsequently used to allocate a humongous
+  // object that may be less than the region size).
+  if (retained_region != NULL &&
+      !retained_region->in_collection_set() &&
+      !(retained_region->top() == retained_region->end()) &&
+      !retained_region->is_empty() &&
+      !retained_region->isHumongous()) {
+    retained_region->record_top_and_timestamp();
+    // The retained region was added to the old region set when it was
+    // retired. We have to remove it now, since we don't allow regions
+    // we allocate to in the region sets. We'll re-add it later, when
+    // it's retired again.
+    _g1h->_old_set.remove(retained_region);
+    bool during_im = _g1h->g1_policy()->during_initial_mark_pause();
+    retained_region->note_start_of_copying(during_im);
+    old->set(retained_region);
+    _g1h->_hr_printer.reuse(retained_region);
+    evacuation_info.set_alloc_regions_used_before(retained_region->used());
+  }
+}
+
+void G1DefaultAllocator::init_gc_alloc_regions(EvacuationInfo& evacuation_info) {
+  assert_at_safepoint(true /* should_be_vm_thread */);
+
+  _survivor_gc_alloc_region.init();
+  _old_gc_alloc_region.init();
+  reuse_retained_old_region(evacuation_info,
+                            &_old_gc_alloc_region,
+                            &_retained_old_gc_alloc_region);
+}
+
+void G1DefaultAllocator::release_gc_alloc_regions(uint no_of_gc_workers, EvacuationInfo& evacuation_info) {
+  AllocationContext_t context = AllocationContext::current();
+  evacuation_info.set_allocation_regions(survivor_gc_alloc_region(context)->count() +
+                                         old_gc_alloc_region(context)->count());
+  survivor_gc_alloc_region(context)->release();
+  // If we have an old GC alloc region to release, we'll save it in
+  // _retained_old_gc_alloc_region. If we don't
+  // _retained_old_gc_alloc_region will become NULL. This is what we
+  // want either way so no reason to check explicitly for either
+  // condition.
+  _retained_old_gc_alloc_region = old_gc_alloc_region(context)->release();
+
+  if (ResizePLAB) {
+    _g1h->_survivor_plab_stats.adjust_desired_plab_sz(no_of_gc_workers);
+    _g1h->_old_plab_stats.adjust_desired_plab_sz(no_of_gc_workers);
+  }
+}
+
+void G1DefaultAllocator::abandon_gc_alloc_regions() {
+  assert(survivor_gc_alloc_region(AllocationContext::current())->get() == NULL, "pre-condition");
+  assert(old_gc_alloc_region(AllocationContext::current())->get() == NULL, "pre-condition");
+  _retained_old_gc_alloc_region = NULL;
+}
+
+G1ParGCAllocBuffer::G1ParGCAllocBuffer(size_t gclab_word_size) :
+  ParGCAllocBuffer(gclab_word_size), _retired(true) { }
+
+HeapWord* G1ParGCAllocator::allocate_slow(GCAllocPurpose purpose, size_t word_sz, AllocationContext_t context) {
+  HeapWord* obj = NULL;
+  size_t gclab_word_size = _g1h->desired_plab_sz(purpose);
+  if (word_sz * 100 < gclab_word_size * ParallelGCBufferWastePct) {
+    G1ParGCAllocBuffer* alloc_buf = alloc_buffer(purpose, context);
+    add_to_alloc_buffer_waste(alloc_buf->words_remaining());
+    alloc_buf->retire(false /* end_of_gc */, false /* retain */);
+
+    HeapWord* buf = _g1h->par_allocate_during_gc(purpose, gclab_word_size, context);
+    if (buf == NULL) {
+      return NULL; // Let caller handle allocation failure.
+    }
+    // Otherwise.
+    alloc_buf->set_word_size(gclab_word_size);
+    alloc_buf->set_buf(buf);
+
+    obj = alloc_buf->allocate(word_sz);
+    assert(obj != NULL, "buffer was definitely big enough...");
+  } else {
+    obj = _g1h->par_allocate_during_gc(purpose, word_sz, context);
+  }
+  return obj;
+}
+
+G1DefaultParGCAllocator::G1DefaultParGCAllocator(G1CollectedHeap* g1h) :
+            G1ParGCAllocator(g1h),
+            _surviving_alloc_buffer(g1h->desired_plab_sz(GCAllocForSurvived)),
+            _tenured_alloc_buffer(g1h->desired_plab_sz(GCAllocForTenured)) {
+
+  _alloc_buffers[GCAllocForSurvived] = &_surviving_alloc_buffer;
+  _alloc_buffers[GCAllocForTenured]  = &_tenured_alloc_buffer;
+
+}
+
+void G1DefaultParGCAllocator::retire_alloc_buffers() {
+  for (int ap = 0; ap < GCAllocPurposeCount; ++ap) {
+    size_t waste = _alloc_buffers[ap]->words_remaining();
+    add_to_alloc_buffer_waste(waste);
+    _alloc_buffers[ap]->flush_stats_and_retire(_g1h->stats_for_purpose((GCAllocPurpose)ap),
+                                               true /* end_of_gc */,
+                                               false /* retain */);
+  }
+}

src/share/vm/gc_implementation/g1/g1Allocator.hpp

+/*
+ * Copyright (c) 2014, 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_G1ALLOCATOR_HPP
+#define SHARE_VM_GC_IMPLEMENTATION_G1_G1ALLOCATOR_HPP
+
+#include "gc_implementation/g1/g1AllocationContext.hpp"
+#include "gc_implementation/g1/g1AllocRegion.hpp"
+#include "gc_implementation/shared/parGCAllocBuffer.hpp"
+
+enum GCAllocPurpose {
+  GCAllocForTenured,
+  GCAllocForSurvived,
+  GCAllocPurposeCount
+};
+
+// Base class for G1 allocators.
+class G1Allocator : public CHeapObj<mtGC> {
+  friend class VMStructs;
+protected:
+  G1CollectedHeap* _g1h;
+
+  // Outside of GC pauses, the number of bytes used in all regions other
+  // than the current allocation region.
+  size_t _summary_bytes_used;
+
+public:
+   G1Allocator(G1CollectedHeap* heap) :
+     _g1h(heap), _summary_bytes_used(0) { }
+
+   static G1Allocator* create_allocator(G1CollectedHeap* g1h);
+
+   virtual void init_mutator_alloc_region() = 0;
+   virtual void release_mutator_alloc_region() = 0;
+
+   virtual void init_gc_alloc_regions(EvacuationInfo& evacuation_info) = 0;
+   virtual void release_gc_alloc_regions(uint no_of_gc_workers, EvacuationInfo& evacuation_info) = 0;
+   virtual void abandon_gc_alloc_regions() = 0;
+
+   virtual MutatorAllocRegion*    mutator_alloc_region(AllocationContext_t context) = 0;
+   virtual SurvivorGCAllocRegion* survivor_gc_alloc_region(AllocationContext_t context) = 0;
+   virtual OldGCAllocRegion*      old_gc_alloc_region(AllocationContext_t context) = 0;
+   virtual size_t                 used() = 0;
+   virtual bool                   is_retained_old_region(HeapRegion* hr) = 0;
+
+   void                           reuse_retained_old_region(EvacuationInfo& evacuation_info,
+                                                            OldGCAllocRegion* old,
+                                                            HeapRegion** retained);
+
+   size_t used_unlocked() const {
+     return _summary_bytes_used;
+   }
+
+   void increase_used(size_t bytes) {
+     _summary_bytes_used += bytes;
+   }
+
+   void decrease_used(size_t bytes) {
+     assert(_summary_bytes_used >= bytes,
+            err_msg("invariant: _summary_bytes_used: "SIZE_FORMAT" should be >= bytes: "SIZE_FORMAT,
+                _summary_bytes_used, bytes));
+     _summary_bytes_used -= bytes;
+   }
+
+   void set_used(size_t bytes) {
+     _summary_bytes_used = bytes;
+   }
+};
+
+// The default allocator for G1.
+class G1DefaultAllocator : public G1Allocator {
+protected:
+  // Alloc region used to satisfy mutator allocation requests.
+  MutatorAllocRegion _mutator_alloc_region;
+
+  // Alloc region used to satisfy allocation requests by the GC for
+  // survivor objects.
+  SurvivorGCAllocRegion _survivor_gc_alloc_region;
+
+  // Alloc region used to satisfy allocation requests by the GC for
+  // old objects.
+  OldGCAllocRegion _old_gc_alloc_region;
+
+  HeapRegion* _retained_old_gc_alloc_region;
+public:
+  G1DefaultAllocator(G1CollectedHeap* heap) : G1Allocator(heap), _retained_old_gc_alloc_region(NULL) { }
+
+  virtual void init_mutator_alloc_region();
+  virtual void release_mutator_alloc_region();
+
+  virtual void init_gc_alloc_regions(EvacuationInfo& evacuation_info);
+  virtual void release_gc_alloc_regions(uint no_of_gc_workers, EvacuationInfo& evacuation_info);
+  virtual void abandon_gc_alloc_regions();
+
+  virtual bool is_retained_old_region(HeapRegion* hr) {
+    return _retained_old_gc_alloc_region == hr;
+  }
+
+  virtual MutatorAllocRegion* mutator_alloc_region(AllocationContext_t context) {
+    return &_mutator_alloc_region;
+  }
+
+  virtual SurvivorGCAllocRegion* survivor_gc_alloc_region(AllocationContext_t context) {
+    return &_survivor_gc_alloc_region;
+  }
+
+  virtual OldGCAllocRegion* old_gc_alloc_region(AllocationContext_t context) {
+    return &_old_gc_alloc_region;
+  }
+
+  virtual size_t used() {
+    assert(Heap_lock->owner() != NULL,
+           "Should be owned on this thread's behalf.");
+    size_t result = _summary_bytes_used;
+
+    // Read only once in case it is set to NULL concurrently
+    HeapRegion* hr = mutator_alloc_region(AllocationContext::current())->get();
+    if (hr != NULL) {
+      result += hr->used();
+    }
+    return result;
+  }
+};
+
+class G1ParGCAllocBuffer: public ParGCAllocBuffer {
+private:
+  bool _retired;
+
+public:
+  G1ParGCAllocBuffer(size_t gclab_word_size);
+  virtual ~G1ParGCAllocBuffer() {
+    guarantee(_retired, "Allocation buffer has not been retired");
+  }
+
+  virtual void set_buf(HeapWord* buf) {
+    ParGCAllocBuffer::set_buf(buf);
+    _retired = false;
+  }
+
+  virtual void retire(bool end_of_gc, bool retain) {
+    if (_retired) {
+      return;
+    }
+    ParGCAllocBuffer::retire(end_of_gc, retain);
+    _retired = true;
+  }
+};
+
+class G1ParGCAllocator : public CHeapObj<mtGC> {
+  friend class G1ParScanThreadState;
+protected:
+  G1CollectedHeap* _g1h;
+
+  size_t _alloc_buffer_waste;
+  size_t _undo_waste;
+
+  void add_to_alloc_buffer_waste(size_t waste) { _alloc_buffer_waste += waste; }
+  void add_to_undo_waste(size_t waste)         { _undo_waste += waste; }
+
+  HeapWord* allocate_slow(GCAllocPurpose purpose, size_t word_sz, AllocationContext_t context);
+
+  virtual void retire_alloc_buffers() = 0;
+  virtual G1ParGCAllocBuffer* alloc_buffer(GCAllocPurpose purpose, AllocationContext_t context) = 0;
+
+public:
+  G1ParGCAllocator(G1CollectedHeap* g1h) :
+    _g1h(g1h), _alloc_buffer_waste(0), _undo_waste(0) {
+  }
+
+  static G1ParGCAllocator* create_allocator(G1CollectedHeap* g1h);
+
+  size_t alloc_buffer_waste() { return _alloc_buffer_waste; }
+  size_t undo_waste() {return _undo_waste; }
+
+  HeapWord* allocate(GCAllocPurpose purpose, size_t word_sz, AllocationContext_t context) {
+    HeapWord* obj = NULL;
+    if (purpose == GCAllocForSurvived) {
+      obj = alloc_buffer(purpose, context)->allocate_aligned(word_sz, SurvivorAlignmentInBytes);
+    } else {
+      obj = alloc_buffer(purpose, context)->allocate(word_sz);
+    }
+    if (obj != NULL) {
+      return obj;
+    }
+    return allocate_slow(purpose, word_sz, context);
+  }
+
+  void undo_allocation(GCAllocPurpose purpose, HeapWord* obj, size_t word_sz, AllocationContext_t context) {
+    if (alloc_buffer(purpose, context)->contains(obj)) {
+      assert(alloc_buffer(purpose, context)->contains(obj + word_sz - 1),
+             "should contain whole object");
+      alloc_buffer(purpose, context)->undo_allocation(obj, word_sz);
+    } else {
+      CollectedHeap::fill_with_object(obj, word_sz);
+      add_to_undo_waste(word_sz);
+    }
+  }
+};
+
+class G1DefaultParGCAllocator : public G1ParGCAllocator {
+  G1ParGCAllocBuffer  _surviving_alloc_buffer;
+  G1ParGCAllocBuffer  _tenured_alloc_buffer;
+  G1ParGCAllocBuffer* _alloc_buffers[GCAllocPurposeCount];
+
+public:
+  G1DefaultParGCAllocator(G1CollectedHeap* g1h);
+
+  virtual G1ParGCAllocBuffer* alloc_buffer(GCAllocPurpose purpose, AllocationContext_t context) {
+    return _alloc_buffers[purpose];
+  }
+
+  virtual void retire_alloc_buffers() ;
+};
+
+#endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1ALLOCATOR_HPP

src/share/vm/gc_implementation/g1/g1Allocator_ext.cpp

+/*
+ * Copyright (c) 2014, 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.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "gc_implementation/g1/g1Allocator.hpp"
+#include "gc_implementation/g1/g1CollectedHeap.hpp"
+
+G1Allocator* G1Allocator::create_allocator(G1CollectedHeap* g1h) {
+  return new G1DefaultAllocator(g1h);
+}
+
+G1ParGCAllocator* G1ParGCAllocator::create_allocator(G1CollectedHeap* g1h) {
+  return new G1DefaultParGCAllocator(g1h);
+}

src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp

@@ -25,6 +25,8 @@
 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTEDHEAP_HPP
 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTEDHEAP_HPP
 
+#include "gc_implementation/g1/g1AllocationContext.hpp"
+#include "gc_implementation/g1/g1Allocator.hpp"
 #include "gc_implementation/g1/concurrentMark.hpp"
 #include "gc_implementation/g1/evacuationInfo.hpp"
 #include "gc_implementation/g1/g1AllocRegion.hpp"
@@ -80,12 +82,6 @@ typedef GenericTaskQueueSet<RefToScanQueue, mtGC> RefToScanQueueSet;
 typedef int RegionIdx_t;   // needs to hold [ 0..max_regions() )
 typedef int CardIdx_t;     // needs to hold [ 0..CardsPerRegion )
 
-enum GCAllocPurpose {
-  GCAllocForTenured,
-  GCAllocForSurvived,
-  GCAllocPurposeCount
-};
-
 class YoungList : public CHeapObj<mtGC> {
 private:
   G1CollectedHeap* _g1h;
@@ -158,40 +154,6 @@ public:
   void          print();
 };
 
-class MutatorAllocRegion : public G1AllocRegion {
-protected:
-  virtual HeapRegion* allocate_new_region(size_t word_size, bool force);
-  virtual void retire_region(HeapRegion* alloc_region, size_t allocated_bytes);
-public:
-  MutatorAllocRegion()
-    : G1AllocRegion("Mutator Alloc Region", false /* bot_updates */) { }
-};
-
-class SurvivorGCAllocRegion : public G1AllocRegion {
-protected:
-  virtual HeapRegion* allocate_new_region(size_t word_size, bool force);
-  virtual void retire_region(HeapRegion* alloc_region, size_t allocated_bytes);
-public:
-  SurvivorGCAllocRegion()
-  : G1AllocRegion("Survivor GC Alloc Region", false /* bot_updates */) { }
-};
-
-class OldGCAllocRegion : public G1AllocRegion {
-protected:
-  virtual HeapRegion* allocate_new_region(size_t word_size, bool force);
-  virtual void retire_region(HeapRegion* alloc_region, size_t allocated_bytes);
-public:
-  OldGCAllocRegion()
-  : G1AllocRegion("Old GC Alloc Region", true /* bot_updates */) { }
-
-  // This specialization of release() makes sure that the last card that has been
-  // allocated into has been completely filled by a dummy object.
-  // This avoids races when remembered set scanning wants to update the BOT of the
-  // last card in the retained old gc alloc region, and allocation threads
-  // allocating into that card at the same time.
-  virtual HeapRegion* release();
-};
-
 // The G1 STW is alive closure.
 // An instance is embedded into the G1CH and used as the
 // (optional) _is_alive_non_header closure in the STW
@@ -222,6 +184,9 @@ class G1CollectedHeap : public SharedHeap {
   friend class MutatorAllocRegion;
   friend class SurvivorGCAllocRegion;
   friend class OldGCAllocRegion;
+  friend class G1Allocator;
+  friend class G1DefaultAllocator;
+  friend class G1ResManAllocator;
 
   // Closures used in implementation.
   template <G1Barrier barrier, G1Mark do_mark_object>
@@ -232,6 +197,8 @@ class G1CollectedHeap : public SharedHeap {
   friend class G1ParScanClosureSuper;
   friend class G1ParEvacuateFollowersClosure;
   friend class G1ParTask;
+  friend class G1ParGCAllocator;
+  friend class G1DefaultParGCAllocator;
   friend class G1FreeGarbageRegionClosure;
   friend class RefineCardTableEntryClosure;
   friend class G1PrepareCompactClosure;
@@ -293,44 +260,15 @@ private:
   // The sequence of all heap regions in the heap.
   HeapRegionManager _hrm;
 
-  // Alloc region used to satisfy mutator allocation requests.
-  MutatorAllocRegion _mutator_alloc_region;
-
-  // Alloc region used to satisfy allocation requests by the GC for
-  // survivor objects.
-  SurvivorGCAllocRegion _survivor_gc_alloc_region;
+  // Class that handles the different kinds of allocations.
+  G1Allocator* _allocator;
 
   // PLAB sizing policy for survivors.
   PLABStats _survivor_plab_stats;
 
-  // Alloc region used to satisfy allocation requests by the GC for
-  // old objects.
-  OldGCAllocRegion _old_gc_alloc_region;
-
   // PLAB sizing policy for tenured objects.
   PLABStats _old_plab_stats;
 
-  PLABStats* stats_for_purpose(GCAllocPurpose purpose) {
-    PLABStats* stats = NULL;
-
-    switch (purpose) {
-    case GCAllocForSurvived:
-      stats = &_survivor_plab_stats;
-      break;
-    case GCAllocForTenured:
-      stats = &_old_plab_stats;
-      break;
-    default:
-      assert(false, "unrecognized GCAllocPurpose");
-    }
-
-    return stats;
-  }
-
-  // The last old region we allocated to during the last GC.
-  // Typically, it is not full so we should re-use it during the next GC.
-  HeapRegion* _retained_old_gc_alloc_region;
-
   // It specifies whether we should attempt to expand the heap after a
   // region allocation failure. If heap expansion fails we set this to
   // false so that we don't re-attempt the heap expansion (it's likely
@@ -348,9 +286,6 @@ private:
   // It initializes the GC alloc regions at the start of a GC.
   void init_gc_alloc_regions(EvacuationInfo& evacuation_info);
 
-  // Setup the retained old gc alloc region as the currrent old gc alloc region.
-  void use_retained_old_gc_alloc_region(EvacuationInfo& evacuation_info);
-
   // It releases the GC alloc regions at the end of a GC.
   void release_gc_alloc_regions(uint no_of_gc_workers, EvacuationInfo& evacuation_info);
 
@@ -361,13 +296,6 @@ private:
   // Helper for monitoring and management support.
   G1MonitoringSupport* _g1mm;
 
-  // Determines PLAB size for a particular allocation purpose.
-  size_t desired_plab_sz(GCAllocPurpose purpose);
-
-  // Outside of GC pauses, the number of bytes used in all regions other
-  // than the current allocation region.
-  size_t _summary_bytes_used;
-
   // Records whether the region at the given index is kept live by roots or
   // references from the young generation.
   class HumongousIsLiveBiasedMappedArray : public G1BiasedMappedArray<bool> {
@@ -525,11 +453,12 @@ protected:
   // humongous region.
   HeapWord* humongous_obj_allocate_initialize_regions(uint first,
                                                       uint num_regions,
-                                                      size_t word_size);
+                                                      size_t word_size,
+                                                      AllocationContext_t context);
 
   // Attempt to allocate a humongous object of the given size. Return
   // NULL if unsuccessful.
-  HeapWord* humongous_obj_allocate(size_t word_size);
+  HeapWord* humongous_obj_allocate(size_t word_size, AllocationContext_t context);
 
   // The following two methods, allocate_new_tlab() and
   // mem_allocate(), are the two main entry points from the runtime
@@ -585,6 +514,7 @@ protected:
   // retry the allocation attempt, potentially scheduling a GC
   // pause. This should only be used for non-humongous allocations.
   HeapWord* attempt_allocation_slow(size_t word_size,
+                                    AllocationContext_t context,
                                     unsigned int* gc_count_before_ret,
                                     int* gclocker_retry_count_ret);
 
@@ -599,7 +529,8 @@ protected:
   // specifies whether the mutator alloc region is expected to be NULL
   // or not.
   HeapWord* attempt_allocation_at_safepoint(size_t word_size,
-                                       bool expect_null_mutator_alloc_region);
+                                            AllocationContext_t context,
+                                            bool expect_null_mutator_alloc_region);
 
   // It dirties the cards that cover the block so that so that the post
   // write barrier never queues anything when updating objects on this
@@ -611,7 +542,9 @@ protected:
   // allocation region, either by picking one or expanding the
   // heap, and then allocate a block of the given size. The block
   // may not be a humongous - it must fit into a single heap region.
-  HeapWord* par_allocate_during_gc(GCAllocPurpose purpose, size_t word_size);
+  HeapWord* par_allocate_during_gc(GCAllocPurpose purpose,
+                                   size_t word_size,
+                                   AllocationContext_t context);
 
   HeapWord* allocate_during_gc_slow(GCAllocPurpose purpose,
                                     HeapRegion*    alloc_region,
@@ -623,10 +556,12 @@ protected:
   void par_allocate_remaining_space(HeapRegion* r);
 
   // Allocation attempt during GC for a survivor object / PLAB.
-  inline HeapWord* survivor_attempt_allocation(size_t word_size);
+  inline HeapWord* survivor_attempt_allocation(size_t word_size,
+                                               AllocationContext_t context);
 
   // Allocation attempt during GC for an old object / PLAB.
-  inline HeapWord* old_attempt_allocation(size_t word_size);
+  inline HeapWord* old_attempt_allocation(size_t word_size,
+                                          AllocationContext_t context);
 
   // These methods are the "callbacks" from the G1AllocRegion class.
 
@@ -665,13 +600,15 @@ protected:
   // Callback from VM_G1CollectForAllocation operation.
   // This function does everything necessary/possible to satisfy a
   // failed allocation request (including collection, expansion, etc.)
-  HeapWord* satisfy_failed_allocation(size_t word_size, bool* succeeded);
+  HeapWord* satisfy_failed_allocation(size_t word_size,
+                                      AllocationContext_t context,
+                                      bool* succeeded);
 
   // Attempting to expand the heap sufficiently
   // to support an allocation of the given "word_size".  If
   // successful, perform the allocation and return the address of the
   // allocated block, or else "NULL".
-  HeapWord* expand_and_allocate(size_t word_size);
+  HeapWord* expand_and_allocate(size_t word_size, AllocationContext_t context);
 
   // Process any reference objects discovered during
   // an incremental evacuation pause.
@@ -694,6 +631,27 @@ public:
   // (Rounds up to a HeapRegion boundary.)
   bool expand(size_t expand_bytes);
 
+  // Returns the PLAB statistics given a purpose.
+  PLABStats* stats_for_purpose(GCAllocPurpose purpose) {
+    PLABStats* stats = NULL;
+
+    switch (purpose) {
+    case GCAllocForSurvived:
+      stats = &_survivor_plab_stats;
+      break;
+    case GCAllocForTenured:
+      stats = &_old_plab_stats;
+      break;
+    default:
+      assert(false, "unrecognized GCAllocPurpose");
+    }
+
+    return stats;
+  }
+
+  // Determines PLAB size for a particular allocation purpose.
+  size_t desired_plab_sz(GCAllocPurpose purpose);
+
   // Do anything common to GC's.
   virtual void gc_prologue(bool full);
   virtual void gc_epilogue(bool full);
@@ -1271,7 +1229,7 @@ public:
   // Determine whether the given region is one that we are using as an
   // old GC alloc region.
   bool is_old_gc_alloc_region(HeapRegion* hr) {
-    return hr == _retained_old_gc_alloc_region;
+    return _allocator->is_retained_old_region(hr);
   }
 
   // Perform a collection of the heap; intended for use in implementing
@@ -1752,28 +1710,4 @@ protected:
   size_t _max_heap_capacity;
 };
 
-class G1ParGCAllocBuffer: public ParGCAllocBuffer {
-private:
-  bool        _retired;
-
-public:
-  G1ParGCAllocBuffer(size_t gclab_word_size);
-  virtual ~G1ParGCAllocBuffer() {
-    guarantee(_retired, "Allocation buffer has not been retired");
-  }
-
-  virtual void set_buf(HeapWord* buf) {
-    ParGCAllocBuffer::set_buf(buf);
-    _retired = false;
-  }
-
-  virtual void retire(bool end_of_gc, bool retain) {
-    if (_retired) {
-      return;
-    }
-    ParGCAllocBuffer::retire(end_of_gc, retain);
-    _retired = true;
-  }
-};
-
 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTEDHEAP_HPP

src/share/vm/gc_implementation/g1/g1CollectedHeap.inline.hpp

@@ -98,10 +98,12 @@ inline HeapWord* G1CollectedHeap::attempt_allocation(size_t word_size,
   assert(!isHumongous(word_size), "attempt_allocation() should not "
          "be called for humongous allocation requests");
 
-  HeapWord* result = _mutator_alloc_region.attempt_allocation(word_size,
-                                                      false /* bot_updates */);
+  AllocationContext_t context = AllocationContext::current();
+  HeapWord* result = _allocator->mutator_alloc_region(context)->attempt_allocation(word_size,
+                                                                                   false /* bot_updates */);
   if (result == NULL) {
     result = attempt_allocation_slow(word_size,
+                                     context,
                                      gc_count_before_ret,
                                      gclocker_retry_count_ret);
   }
@@ -112,17 +114,17 @@ inline HeapWord* G1CollectedHeap::attempt_allocation(size_t word_size,
   return result;
 }
 
-inline HeapWord* G1CollectedHeap::survivor_attempt_allocation(size_t
-                                                              word_size) {
+inline HeapWord* G1CollectedHeap::survivor_attempt_allocation(size_t word_size,
+                                                              AllocationContext_t context) {
   assert(!isHumongous(word_size),
          "we should not be seeing humongous-size allocations in this path");
 
-  HeapWord* result = _survivor_gc_alloc_region.attempt_allocation(word_size,
-                                                      false /* bot_updates */);
+  HeapWord* result = _allocator->survivor_gc_alloc_region(context)->attempt_allocation(word_size,
+                                                                                       false /* bot_updates */);
   if (result == NULL) {
     MutexLockerEx x(FreeList_lock, Mutex::_no_safepoint_check_flag);
-    result = _survivor_gc_alloc_region.attempt_allocation_locked(word_size,
-                                                      false /* bot_updates */);
+    result = _allocator->survivor_gc_alloc_region(context)->attempt_allocation_locked(word_size,
+                                                                                      false /* bot_updates */);
   }
   if (result != NULL) {
     dirty_young_block(result, word_size);
@@ -130,16 +132,17 @@ inline HeapWord* G1CollectedHeap::survivor_attempt_allocation(size_t
   return result;
 }
 
-inline HeapWord* G1CollectedHeap::old_attempt_allocation(size_t word_size) {
+inline HeapWord* G1CollectedHeap::old_attempt_allocation(size_t word_size,
+                                                         AllocationContext_t context) {
   assert(!isHumongous(word_size),
          "we should not be seeing humongous-size allocations in this path");
 
-  HeapWord* result = _old_gc_alloc_region.attempt_allocation(word_size,
-                                                       true /* bot_updates */);
+  HeapWord* result = _allocator->old_gc_alloc_region(context)->attempt_allocation(word_size,
+                                                                                  true /* bot_updates */);
   if (result == NULL) {
     MutexLockerEx x(FreeList_lock, Mutex::_no_safepoint_check_flag);
-    result = _old_gc_alloc_region.attempt_allocation_locked(word_size,
-                                                       true /* bot_updates */);
+    result = _allocator->old_gc_alloc_region(context)->attempt_allocation_locked(word_size,
+                                                                                 true /* bot_updates */);
   }
   return result;
 }

src/share/vm/gc_implementation/g1/g1ParScanThreadState.cpp

@@ -38,11 +38,8 @@ G1ParScanThreadState::G1ParScanThreadState(G1CollectedHeap* g1h, uint queue_num,
     _g1_rem(g1h->g1_rem_set()),
     _hash_seed(17), _queue_num(queue_num),
     _term_attempts(0),
-    _surviving_alloc_buffer(g1h->desired_plab_sz(GCAllocForSurvived)),
-    _tenured_alloc_buffer(g1h->desired_plab_sz(GCAllocForTenured)),
     _age_table(false), _scanner(g1h, rp),
-    _strong_roots_time(0), _term_time(0),
-    _alloc_buffer_waste(0), _undo_waste(0) {
+    _strong_roots_time(0), _term_time(0) {
   _scanner.set_par_scan_thread_state(this);
   // we allocate G1YoungSurvRateNumRegions plus one entries, since
   // we "sacrifice" entry 0 to keep track of surviving bytes for
@@ -60,14 +57,14 @@ G1ParScanThreadState::G1ParScanThreadState(G1CollectedHeap* g1h, uint queue_num,
   _surviving_young_words = _surviving_young_words_base + PADDING_ELEM_NUM;
   memset(_surviving_young_words, 0, (size_t) real_length * sizeof(size_t));
 
-  _alloc_buffers[GCAllocForSurvived] = &_surviving_alloc_buffer;
-  _alloc_buffers[GCAllocForTenured]  = &_tenured_alloc_buffer;
+  _g1_par_allocator = G1ParGCAllocator::create_allocator(_g1h);
 
   _start = os::elapsedTime();
 }
 
 G1ParScanThreadState::~G1ParScanThreadState() {
-  retire_alloc_buffers();
+  _g1_par_allocator->retire_alloc_buffers();
+  delete _g1_par_allocator;
   FREE_C_HEAP_ARRAY(size_t, _surviving_young_words_base, mtGC);
 }
 
@@ -90,14 +87,16 @@ G1ParScanThreadState::print_termination_stats(int i,
   const double elapsed_ms = elapsed_time() * 1000.0;
   const double s_roots_ms = strong_roots_time() * 1000.0;
   const double term_ms    = term_time() * 1000.0;
+  const size_t alloc_buffer_waste = _g1_par_allocator->alloc_buffer_waste();
+  const size_t undo_waste         = _g1_par_allocator->undo_waste();
   st->print_cr("%3d %9.2f %9.2f %6.2f "
                "%9.2f %6.2f " SIZE_FORMAT_W(8) " "
                SIZE_FORMAT_W(7) " " SIZE_FORMAT_W(7) " " SIZE_FORMAT_W(7),
                i, elapsed_ms, s_roots_ms, s_roots_ms * 100 / elapsed_ms,
                term_ms, term_ms * 100 / elapsed_ms, term_attempts(),
-               (alloc_buffer_waste() + undo_waste()) * HeapWordSize / K,
-               alloc_buffer_waste() * HeapWordSize / K,
-               undo_waste() * HeapWordSize / K);
+               (alloc_buffer_waste + undo_waste) * HeapWordSize / K,
+               alloc_buffer_waste * HeapWordSize / K,
+               undo_waste * HeapWordSize / K);
 }
 
 #ifdef ASSERT
@@ -164,12 +163,13 @@ oop G1ParScanThreadState::copy_to_survivor_space(oop const old) {
                                            : m->age();
   GCAllocPurpose alloc_purpose = g1p->evacuation_destination(from_region, age,
                                                              word_sz);
-  HeapWord* obj_ptr = allocate(alloc_purpose, word_sz);
+  AllocationContext_t context = from_region->allocation_context();
+  HeapWord* obj_ptr = _g1_par_allocator->allocate(alloc_purpose, word_sz, context);
 #ifndef PRODUCT
   // Should this evacuation fail?
   if (_g1h->evacuation_should_fail()) {
     if (obj_ptr != NULL) {
-      undo_allocation(alloc_purpose, obj_ptr, word_sz);
+      _g1_par_allocator->undo_allocation(alloc_purpose, obj_ptr, word_sz, context);
       obj_ptr = NULL;
     }
   }
@@ -246,66 +246,8 @@ oop G1ParScanThreadState::copy_to_survivor_space(oop const old) {
       obj->oop_iterate_backwards(&_scanner);
     }
   } else {
-    undo_allocation(alloc_purpose, obj_ptr, word_sz);
+    _g1_par_allocator->undo_allocation(alloc_purpose, obj_ptr, word_sz, context);
     obj = forward_ptr;
   }
   return obj;
 }
-
-HeapWord* G1ParScanThreadState::allocate_slow(GCAllocPurpose purpose, size_t word_sz) {
-  HeapWord* obj = NULL;
-  size_t gclab_word_size = _g1h->desired_plab_sz(purpose);
-  if (word_sz * 100 < gclab_word_size * ParallelGCBufferWastePct) {
-    G1ParGCAllocBuffer* alloc_buf = alloc_buffer(purpose);
-    add_to_alloc_buffer_waste(alloc_buf->words_remaining());
-    alloc_buf->retire(false /* end_of_gc */, false /* retain */);
-
-    HeapWord* buf = _g1h->par_allocate_during_gc(purpose, gclab_word_size);
-    if (buf == NULL) {
-      return NULL; // Let caller handle allocation failure.
-    }
-    // Otherwise.
-    alloc_buf->set_word_size(gclab_word_size);
-    alloc_buf->set_buf(buf);
-
-    obj = alloc_buf->allocate(word_sz);
-    assert(obj != NULL, "buffer was definitely big enough...");
-  } else {
-    obj = _g1h->par_allocate_during_gc(purpose, word_sz);
-  }
-  return obj;
-}
-
-void G1ParScanThreadState::undo_allocation(GCAllocPurpose purpose, HeapWord* obj, size_t word_sz) {
-  if (alloc_buffer(purpose)->contains(obj)) {
-    assert(alloc_buffer(purpose)->contains(obj + word_sz - 1),
-           "should contain whole object");
-    alloc_buffer(purpose)->undo_allocation(obj, word_sz);
-  } else {
-    CollectedHeap::fill_with_object(obj, word_sz);
-    add_to_undo_waste(word_sz);
-  }
-}
-
-HeapWord* G1ParScanThreadState::allocate(GCAllocPurpose purpose, size_t word_sz) {
-  HeapWord* obj = NULL;
-  if (purpose == GCAllocForSurvived) {
-    obj = alloc_buffer(GCAllocForSurvived)->allocate_aligned(word_sz, SurvivorAlignmentInBytes);
-  } else {
-    obj = alloc_buffer(GCAllocForTenured)->allocate(word_sz);
-  }
-  if (obj != NULL) {
-    return obj;
-  }
-  return allocate_slow(purpose, word_sz);
-}
-
-void G1ParScanThreadState::retire_alloc_buffers() {
-  for (int ap = 0; ap < GCAllocPurposeCount; ++ap) {
-    size_t waste = _alloc_buffers[ap]->words_remaining();
-    add_to_alloc_buffer_waste(waste);
-    _alloc_buffers[ap]->flush_stats_and_retire(_g1h->stats_for_purpose((GCAllocPurpose)ap),
-                                               true /* end_of_gc */,
-                                               false /* retain */);
-  }
-}

src/share/vm/gc_implementation/g1/g1ParScanThreadState.hpp

@@ -46,9 +46,8 @@ class G1ParScanThreadState : public StackObj {
   G1SATBCardTableModRefBS* _ct_bs;
   G1RemSet* _g1_rem;
 
-  G1ParGCAllocBuffer  _surviving_alloc_buffer;
-  G1ParGCAllocBuffer  _tenured_alloc_buffer;
-  G1ParGCAllocBuffer* _alloc_buffers[GCAllocPurposeCount];
+  G1ParGCAllocator*   _g1_par_allocator;
+
   ageTable            _age_table;
 
   G1ParScanClosure    _scanner;
@@ -78,7 +77,6 @@ class G1ParScanThreadState : public StackObj {
 #define PADDING_ELEM_NUM (DEFAULT_CACHE_LINE_SIZE / sizeof(size_t))
 
   void   add_to_alloc_buffer_waste(size_t waste) { _alloc_buffer_waste += waste; }
-
   void   add_to_undo_waste(size_t waste)         { _undo_waste += waste; }
 
   DirtyCardQueue& dirty_card_queue()             { return _dcq;  }
@@ -104,13 +102,6 @@ class G1ParScanThreadState : public StackObj {
 
   ageTable*         age_table()       { return &_age_table;       }
 
-  G1ParGCAllocBuffer* alloc_buffer(GCAllocPurpose purpose) {
-    return _alloc_buffers[purpose];
-  }
-
-  size_t alloc_buffer_waste() const              { return _alloc_buffer_waste; }
-  size_t undo_waste() const                      { return _undo_waste; }
-
 #ifdef ASSERT
   bool queue_is_empty() const { return _refs->is_empty(); }
 
@@ -126,12 +117,6 @@ class G1ParScanThreadState : public StackObj {
 
   template <class T> inline void update_rs(HeapRegion* from, T* p, int tid);
 
- private:
-
-  inline HeapWord* allocate(GCAllocPurpose purpose, size_t word_sz);
-  inline HeapWord* allocate_slow(GCAllocPurpose purpose, size_t word_sz);
-  inline void undo_allocation(GCAllocPurpose purpose, HeapWord* obj, size_t word_sz);
-
  public:
 
   void set_evac_failure_closure(OopsInHeapRegionClosure* evac_failure_cl) {
@@ -177,8 +162,6 @@ class G1ParScanThreadState : public StackObj {
   }
 
  private:
-  void retire_alloc_buffers();
-
   #define G1_PARTIAL_ARRAY_MASK 0x2
 
   inline bool has_partial_array_mask(oop* ref) const {

src/share/vm/gc_implementation/g1/heapRegion.cpp

@@ -219,6 +219,7 @@ void HeapRegion::hr_clear(bool par, bool clear_space, bool locked) {
 
   _in_collection_set = false;
 
+  set_allocation_context(AllocationContext::system());
   set_young_index_in_cset(-1);
   uninstall_surv_rate_group();
   set_young_type(NotYoung);
@@ -346,9 +347,9 @@ HeapWord* HeapRegion::next_block_start_careful(HeapWord* addr) {
 
 HeapRegion::HeapRegion(uint hrm_index,
                        G1BlockOffsetSharedArray* sharedOffsetArray,
-                       MemRegion mr) :
+                       MemRegion mr, AllocationContext_t context) :
     G1OffsetTableContigSpace(sharedOffsetArray, mr),
-    _hrm_index(hrm_index),
+    _hrm_index(hrm_index), _allocation_context(context),
     _humongous_type(NotHumongous), _humongous_start_region(NULL),
     _in_collection_set(false),
     _next_in_special_set(NULL), _orig_end(NULL),
@@ -715,6 +716,8 @@ void HeapRegion::verify_strong_code_roots(VerifyOption vo, bool* failures) const
 
 void HeapRegion::print() const { print_on(gclog_or_tty); }
 void HeapRegion::print_on(outputStream* st) const {
+  st->print("AC%4u", allocation_context());
+
   if (isHumongous()) {
     if (startsHumongous())
       st->print(" HS");

src/share/vm/gc_implementation/g1/heapRegion.hpp

@@ -25,6 +25,7 @@
 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP
 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP
 
+#include "gc_implementation/g1/g1AllocationContext.hpp"
 #include "gc_implementation/g1/g1BlockOffsetTable.hpp"
 #include "gc_implementation/g1/g1_specialized_oop_closures.hpp"
 #include "gc_implementation/g1/survRateGroup.hpp"
@@ -236,6 +237,8 @@ class HeapRegion: public G1OffsetTableContigSpace {
   // The index of this region in the heap region sequence.
   uint  _hrm_index;
 
+  AllocationContext_t _allocation_context;
+
   HumongousType _humongous_type;
   // For a humongous region, region in which it starts.
   HeapRegion* _humongous_start_region;
@@ -332,7 +335,8 @@ class HeapRegion: public G1OffsetTableContigSpace {
  public:
   HeapRegion(uint hrm_index,
              G1BlockOffsetSharedArray* sharedOffsetArray,
-             MemRegion mr);
+             MemRegion mr,
+             AllocationContext_t context = AllocationContext::system());
 
   // Initializing the HeapRegion not only resets the data structure, but also
   // resets the BOT for that heap region.
@@ -527,6 +531,14 @@ class HeapRegion: public G1OffsetTableContigSpace {
     _next_in_special_set = r;
   }
 
+  void set_allocation_context(AllocationContext_t context) {
+    _allocation_context = context;
+  }
+
+  AllocationContext_t  allocation_context() const {
+    return _allocation_context;
+  }
+
   // Methods used by the HeapRegionSetBase class and subclasses.
 
   // Getter and setter for the next and prev fields used to link regions into

src/share/vm/gc_implementation/g1/vmStructs_g1.hpp

@@ -45,11 +45,13 @@
   nonstatic_field(HeapRegionManager, _regions,          G1HeapRegionTable)    \
   nonstatic_field(HeapRegionManager, _num_committed,    uint)                 \
                                                                               \
+  nonstatic_field(G1Allocator,     _summary_bytes_used, size_t)               \
+                                                                              \
   nonstatic_field(G1CollectedHeap, _hrm,                HeapRegionManager)    \
-  nonstatic_field(G1CollectedHeap, _summary_bytes_used, size_t)               \
   nonstatic_field(G1CollectedHeap, _g1mm,               G1MonitoringSupport*) \
   nonstatic_field(G1CollectedHeap, _old_set,            HeapRegionSetBase)    \
   nonstatic_field(G1CollectedHeap, _humongous_set,      HeapRegionSetBase)    \
+  nonstatic_field(G1CollectedHeap, _allocator,          G1Allocator*)         \
                                                                               \
   nonstatic_field(G1MonitoringSupport, _eden_committed,     size_t)           \
   nonstatic_field(G1MonitoringSupport, _eden_used,          size_t)           \
@@ -72,14 +74,16 @@
                                                                               \
   declare_type(G1OffsetTableContigSpace, CompactibleSpace)                    \
   declare_type(HeapRegion, G1OffsetTableContigSpace)                          \
-  declare_toplevel_type(HeapRegionManager)                                        \
+  declare_toplevel_type(HeapRegionManager)                                    \
   declare_toplevel_type(HeapRegionSetBase)                                    \
   declare_toplevel_type(HeapRegionSetCount)                                   \
   declare_toplevel_type(G1MonitoringSupport)                                  \
+  declare_toplevel_type(G1Allocator)                                          \
                                                                               \
   declare_toplevel_type(G1CollectedHeap*)                                     \
   declare_toplevel_type(HeapRegion*)                                          \
   declare_toplevel_type(G1MonitoringSupport*)                                 \
+  declare_toplevel_type(G1Allocator*)                                         \
 
 
 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_VMSTRUCTS_G1_HPP

src/share/vm/gc_implementation/g1/vm_operations_g1.cpp

@@ -45,7 +45,8 @@ VM_G1CollectForAllocation::VM_G1CollectForAllocation(
 void VM_G1CollectForAllocation::doit() {
   G1CollectedHeap* g1h = G1CollectedHeap::heap();
   GCCauseSetter x(g1h, _gc_cause);
-  _result = g1h->satisfy_failed_allocation(_word_size, &_pause_succeeded);
+
+  _result = g1h->satisfy_failed_allocation(_word_size, allocation_context(), &_pause_succeeded);
   assert(_result == NULL || _pause_succeeded,
          "if we get back a result, the pause should have succeeded");
 }
@@ -99,7 +100,7 @@ void VM_G1IncCollectionPause::doit() {
 
   if (_word_size > 0) {
     // An allocation has been requested. So, try to do that first.
-    _result = g1h->attempt_allocation_at_safepoint(_word_size,
+    _result = g1h->attempt_allocation_at_safepoint(_word_size, allocation_context(),
                                      false /* expect_null_cur_alloc_region */);
     if (_result != NULL) {
       // If we can successfully allocate before we actually do the
@@ -152,7 +153,7 @@ void VM_G1IncCollectionPause::doit() {
     g1h->do_collection_pause_at_safepoint(_target_pause_time_ms);
   if (_pause_succeeded && _word_size > 0) {
     // An allocation had been requested.
-    _result = g1h->attempt_allocation_at_safepoint(_word_size,
+    _result = g1h->attempt_allocation_at_safepoint(_word_size, allocation_context(),
                                       true /* expect_null_cur_alloc_region */);
   } else {
     assert(_result == NULL, "invariant");

src/share/vm/gc_implementation/g1/vm_operations_g1.hpp

@@ -25,6 +25,7 @@
 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_VM_OPERATIONS_G1_HPP
 #define SHARE_VM_GC_IMPLEMENTATION_G1_VM_OPERATIONS_G1_HPP
 
+#include "gc_implementation/g1/g1AllocationContext.hpp"
 #include "gc_implementation/shared/vmGCOperations.hpp"
 
 // VM_operations for the G1 collector.
@@ -40,6 +41,7 @@ protected:
   size_t    _word_size;
   HeapWord* _result;
   bool      _pause_succeeded;
+  AllocationContext_t _allocation_context;
 
 public:
   VM_G1OperationWithAllocRequest(unsigned int gc_count_before,
@@ -49,6 +51,8 @@ public:
       _word_size(word_size), _result(NULL), _pause_succeeded(false) { }
   HeapWord* result() { return _result; }
   bool pause_succeeded() { return _pause_succeeded; }
+  void set_allocation_context(AllocationContext_t context) { _allocation_context = context; }
+  AllocationContext_t  allocation_context() { return _allocation_context; }
 };
 
 class VM_G1CollectFull: public VM_GC_Operation {

src/share/vm/runtime/vm_operations.hpp

@@ -68,6 +68,7 @@
   template(G1CollectFull)                         \
   template(G1CollectForAllocation)                \
   template(G1IncCollectionPause)                  \
+  template(DestroyAllocationContext)              \
   template(EnableBiasedLocking)                   \
   template(RevokeBias)                            \
   template(BulkRevokeBias)                        \