--- a/hotspot/src/share/vm/gc_implementation/g1/g1Allocator.cpp	Tue Apr 21 10:29:35 2015 -0400
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1Allocator.cpp	Wed Apr 15 11:42:20 2015 -0400
@@ -110,15 +110,15 @@
   _retained_old_gc_alloc_region = NULL;
 }
 
-G1ParGCAllocBuffer::G1ParGCAllocBuffer(size_t gclab_word_size) :
-  ParGCAllocBuffer(gclab_word_size), _retired(true) { }
+G1PLAB::G1PLAB(size_t gclab_word_size) :
+  PLAB(gclab_word_size), _retired(true) { }
 
 HeapWord* G1ParGCAllocator::allocate_direct_or_new_plab(InCSetState dest,
                                                         size_t word_sz,
                                                         AllocationContext_t context) {
   size_t gclab_word_size = _g1h->desired_plab_sz(dest);
   if (word_sz * 100 < gclab_word_size * ParallelGCBufferWastePct) {
-    G1ParGCAllocBuffer* alloc_buf = alloc_buffer(dest, context);
+    G1PLAB* alloc_buf = alloc_buffer(dest, context);
     add_to_alloc_buffer_waste(alloc_buf->words_remaining());
     alloc_buf->retire();
 
@@ -151,7 +151,7 @@
 
 void G1DefaultParGCAllocator::retire_alloc_buffers() {
   for (uint state = 0; state < InCSetState::Num; state++) {
-    G1ParGCAllocBuffer* const buf = _alloc_buffers[state];
+    G1PLAB* const buf = _alloc_buffers[state];
     if (buf != NULL) {
       add_to_alloc_buffer_waste(buf->words_remaining());
       buf->flush_and_retire_stats(_g1h->alloc_buffer_stats(state));

--- a/hotspot/src/share/vm/gc_implementation/g1/g1Allocator.hpp	Tue Apr 21 10:29:35 2015 -0400
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1Allocator.hpp	Wed Apr 15 11:42:20 2015 -0400
@@ -28,7 +28,7 @@
 #include "gc_implementation/g1/g1AllocationContext.hpp"
 #include "gc_implementation/g1/g1AllocRegion.hpp"
 #include "gc_implementation/g1/g1InCSetState.hpp"
-#include "gc_implementation/shared/parGCAllocBuffer.hpp"
+#include "gc_implementation/shared/plab.hpp"
 #include "gc_interface/collectedHeap.hpp"
 
 class EvacuationInfo;
@@ -147,18 +147,18 @@
   }
 };
 
-class G1ParGCAllocBuffer: public ParGCAllocBuffer {
+class G1PLAB: public PLAB {
 private:
   bool _retired;
 
 public:
-  G1ParGCAllocBuffer(size_t gclab_word_size);
-  virtual ~G1ParGCAllocBuffer() {
+  G1PLAB(size_t gclab_word_size);
+  virtual ~G1PLAB() {
     guarantee(_retired, "Allocation buffer has not been retired");
   }
 
   virtual void set_buf(HeapWord* buf) {
-    ParGCAllocBuffer::set_buf(buf);
+    PLAB::set_buf(buf);
     _retired = false;
   }
 
@@ -166,7 +166,7 @@
     if (_retired) {
       return;
     }
-    ParGCAllocBuffer::retire();
+    PLAB::retire();
     _retired = true;
   }
 };
@@ -190,7 +190,7 @@
   void add_to_undo_waste(size_t waste)         { _undo_waste += waste; }
 
   virtual void retire_alloc_buffers() = 0;
-  virtual G1ParGCAllocBuffer* alloc_buffer(InCSetState dest, AllocationContext_t context) = 0;
+  virtual G1PLAB* alloc_buffer(InCSetState dest, AllocationContext_t context) = 0;
 
   // Calculate the survivor space object alignment in bytes. Returns that or 0 if
   // there are no restrictions on survivor alignment.
@@ -229,7 +229,7 @@
   HeapWord* plab_allocate(InCSetState dest,
                           size_t word_sz,
                           AllocationContext_t context) {
-    G1ParGCAllocBuffer* buffer = alloc_buffer(dest, context);
+    G1PLAB* buffer = alloc_buffer(dest, context);
     if (_survivor_alignment_bytes == 0) {
       return buffer->allocate(word_sz);
     } else {
@@ -259,14 +259,14 @@
 };
 
 class G1DefaultParGCAllocator : public G1ParGCAllocator {
-  G1ParGCAllocBuffer  _surviving_alloc_buffer;
-  G1ParGCAllocBuffer  _tenured_alloc_buffer;
-  G1ParGCAllocBuffer* _alloc_buffers[InCSetState::Num];
+  G1PLAB  _surviving_alloc_buffer;
+  G1PLAB  _tenured_alloc_buffer;
+  G1PLAB* _alloc_buffers[InCSetState::Num];
 
 public:
   G1DefaultParGCAllocator(G1CollectedHeap* g1h);
 
-  virtual G1ParGCAllocBuffer* alloc_buffer(InCSetState dest, AllocationContext_t context) {
+  virtual G1PLAB* alloc_buffer(InCSetState dest, AllocationContext_t context) {
     assert(dest.is_valid(),
            err_msg("Allocation buffer index out-of-bounds: " CSETSTATE_FORMAT, dest.value()));
     assert(_alloc_buffers[dest.value()] != NULL,

--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp	Tue Apr 21 10:29:35 2015 -0400
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp	Wed Apr 15 11:42:20 2015 -0400
@@ -39,7 +39,6 @@
 #include "gc_implementation/g1/heapRegionManager.hpp"
 #include "gc_implementation/g1/heapRegionSet.hpp"
 #include "gc_implementation/shared/hSpaceCounters.hpp"
-#include "gc_implementation/shared/parGCAllocBuffer.hpp"
 #include "gc_interface/collectedHeap.hpp"
 #include "memory/barrierSet.hpp"
 #include "memory/memRegion.hpp"

--- a/hotspot/src/share/vm/gc_implementation/parNew/parNewGeneration.cpp	Tue Apr 21 10:29:35 2015 -0400
+++ b/hotspot/src/share/vm/gc_implementation/parNew/parNewGeneration.cpp	Wed Apr 15 11:42:20 2015 -0400
@@ -34,7 +34,7 @@
 #include "gc_implementation/shared/gcTimer.hpp"
 #include "gc_implementation/shared/gcTrace.hpp"
 #include "gc_implementation/shared/gcTraceTime.hpp"
-#include "gc_implementation/shared/parGCAllocBuffer.inline.hpp"
+#include "gc_implementation/shared/plab.inline.hpp"
 #include "gc_implementation/shared/spaceDecorator.hpp"
 #include "memory/defNewGeneration.inline.hpp"
 #include "memory/genCollectedHeap.hpp"
@@ -226,7 +226,7 @@
   // buffer.
   HeapWord* obj = NULL;
   if (!_to_space_full) {
-    ParGCAllocBuffer* const plab = to_space_alloc_buffer();
+    PLAB* const plab = to_space_alloc_buffer();
     Space*            const sp   = to_space();
     if (word_sz * 100 <
         ParallelGCBufferWastePct * plab->word_sz()) {
@@ -236,7 +236,7 @@
       HeapWord* buf_space = sp->par_allocate(buf_size);
       if (buf_space == NULL) {
         const size_t min_bytes =
-          ParGCAllocBuffer::min_size() << LogHeapWordSize;
+          PLAB::min_size() << LogHeapWordSize;
         size_t free_bytes = sp->free();
         while(buf_space == NULL && free_bytes >= min_bytes) {
           buf_size = free_bytes >> LogHeapWordSize;
@@ -252,7 +252,7 @@
         record_survivor_plab(buf_space, buf_size);
         obj = plab->allocate_aligned(word_sz, SurvivorAlignmentInBytes);
         // Note that we cannot compare buf_size < word_sz below
-        // because of AlignmentReserve (see ParGCAllocBuffer::allocate()).
+        // because of AlignmentReserve (see PLAB::allocate()).
         assert(obj != NULL || plab->words_remaining() < word_sz,
                "Else should have been able to allocate");
         // It's conceivable that we may be able to use the

--- a/hotspot/src/share/vm/gc_implementation/parNew/parNewGeneration.hpp	Tue Apr 21 10:29:35 2015 -0400
+++ b/hotspot/src/share/vm/gc_implementation/parNew/parNewGeneration.hpp	Wed Apr 15 11:42:20 2015 -0400
@@ -27,7 +27,7 @@
 
 #include "gc_implementation/parNew/parOopClosures.hpp"
 #include "gc_implementation/shared/gcTrace.hpp"
-#include "gc_implementation/shared/parGCAllocBuffer.hpp"
+#include "gc_implementation/shared/plab.hpp"
 #include "gc_implementation/shared/copyFailedInfo.hpp"
 #include "memory/defNewGeneration.hpp"
 #include "memory/padded.hpp"
@@ -65,7 +65,7 @@
   ObjToScanQueue *_work_queue;
   Stack<oop, mtGC>* const _overflow_stack;
 
-  ParGCAllocBuffer _to_space_alloc_buffer;
+  PLAB _to_space_alloc_buffer;
 
   ParScanWithoutBarrierClosure         _to_space_closure; // scan_without_gc_barrier
   ParScanWithBarrierClosure            _old_gen_closure; // scan_with_gc_barrier
@@ -140,7 +140,7 @@
 
   ObjToScanQueue* work_queue() { return _work_queue; }
 
-  ParGCAllocBuffer* to_space_alloc_buffer() {
+  PLAB* to_space_alloc_buffer() {
     return &_to_space_alloc_buffer;
   }
 

--- a/hotspot/src/share/vm/gc_implementation/shared/parGCAllocBuffer.cpp	Tue Apr 21 10:29:35 2015 -0400
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,134 +0,0 @@
-/*
- * Copyright (c) 2001, 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.
- *
- */
-
-#include "precompiled.hpp"
-#include "gc_implementation/shared/parGCAllocBuffer.hpp"
-#include "memory/threadLocalAllocBuffer.hpp"
-#include "oops/arrayOop.hpp"
-#include "oops/oop.inline.hpp"
-
-size_t ParGCAllocBuffer::min_size() {
-  // Make sure that we return something that is larger than AlignmentReserve
-  return align_object_size(MAX2(MinTLABSize / HeapWordSize, (uintx)oopDesc::header_size())) + AlignmentReserve;
-}
-
-size_t ParGCAllocBuffer::max_size() {
-  return ThreadLocalAllocBuffer::max_size();
-}
-
-ParGCAllocBuffer::ParGCAllocBuffer(size_t desired_plab_sz_) :
-  _word_sz(desired_plab_sz_), _bottom(NULL), _top(NULL),
-  _end(NULL), _hard_end(NULL), _allocated(0), _wasted(0)
-{
-  // ArrayOopDesc::header_size depends on command line initialization.
-  AlignmentReserve = oopDesc::header_size() > MinObjAlignment ? align_object_size(arrayOopDesc::header_size(T_INT)) : 0;
-  assert(min_size() > AlignmentReserve,
-         err_msg("Minimum PLAB size " SIZE_FORMAT" must be larger than alignment reserve " SIZE_FORMAT" "
-                 "to be able to contain objects", min_size(), AlignmentReserve));
-}
-
-// If the minimum object size is greater than MinObjAlignment, we can
-// end up with a shard at the end of the buffer that's smaller than
-// the smallest object.  We can't allow that because the buffer must
-// look like it's full of objects when we retire it, so we make
-// sure we have enough space for a filler int array object.
-size_t ParGCAllocBuffer::AlignmentReserve;
-
-void ParGCAllocBuffer::flush_and_retire_stats(PLABStats* stats) {
-  // Retire the last allocation buffer.
-  size_t unused = retire_internal();
-
-  // Now flush the statistics.
-  stats->add_allocated(_allocated);
-  stats->add_wasted(_wasted);
-  stats->add_unused(unused);
-
-  // Since we have flushed the stats we need to clear  the _allocated and _wasted
-  // fields in case somebody retains an instance of this over GCs. Not doing so
-  // will artifically inflate the values in the statistics.
-  _allocated = 0;
-  _wasted = 0;
-}
-
-void ParGCAllocBuffer::retire() {
-  _wasted += retire_internal();
-}
-
-size_t ParGCAllocBuffer::retire_internal() {
-  size_t result = 0;
-  if (_top < _hard_end) {
-    CollectedHeap::fill_with_object(_top, _hard_end);
-    result += invalidate();
-  }
-  return result;
-}
-
-// Compute desired plab size and latch result for later
-// use. This should be called once at the end of parallel
-// scavenge; it clears the sensor accumulators.
-void PLABStats::adjust_desired_plab_sz(uint no_of_gc_workers) {
-  assert(ResizePLAB, "Not set");
-
-  assert(is_object_aligned(max_size()) && min_size() <= max_size(),
-         "PLAB clipping computation may be incorrect");
-
-  if (_allocated == 0) {
-    assert(_unused == 0,
-           err_msg("Inconsistency in PLAB stats: "
-                   "_allocated: "SIZE_FORMAT", "
-                   "_wasted: "SIZE_FORMAT", "
-                   "_unused: "SIZE_FORMAT,
-                   _allocated, _wasted, _unused));
-
-    _allocated = 1;
-  }
-  double wasted_frac    = (double)_unused / (double)_allocated;
-  size_t target_refills = (size_t)((wasted_frac * TargetSurvivorRatio) / TargetPLABWastePct);
-  if (target_refills == 0) {
-    target_refills = 1;
-  }
-  size_t used = _allocated - _wasted - _unused;
-  size_t recent_plab_sz = used / (target_refills * no_of_gc_workers);
-  // Take historical weighted average
-  _filter.sample(recent_plab_sz);
-  // Clip from above and below, and align to object boundary
-  size_t new_plab_sz = MAX2(min_size(), (size_t)_filter.average());
-  new_plab_sz = MIN2(max_size(), new_plab_sz);
-  new_plab_sz = align_object_size(new_plab_sz);
-  // Latch the result
-  if (PrintPLAB) {
-    gclog_or_tty->print(" (plab_sz = " SIZE_FORMAT" desired_plab_sz = " SIZE_FORMAT") ", recent_plab_sz, new_plab_sz);
-  }
-  _desired_plab_sz = new_plab_sz;
-
-  reset();
-}
-
-#ifndef PRODUCT
-void ParGCAllocBuffer::print() {
-  gclog_or_tty->print_cr("parGCAllocBuffer: _bottom: " PTR_FORMAT "  _top: " PTR_FORMAT
-    "  _end: " PTR_FORMAT "  _hard_end: " PTR_FORMAT ")",
-    p2i(_bottom), p2i(_top), p2i(_end), p2i(_hard_end));
-}
-#endif // !PRODUCT

--- a/hotspot/src/share/vm/gc_implementation/shared/parGCAllocBuffer.hpp	Tue Apr 21 10:29:35 2015 -0400
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,197 +0,0 @@
-/*
- * Copyright (c) 2001, 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_IMPLEMENTATION_PARNEW_PARGCALLOCBUFFER_HPP
-#define SHARE_VM_GC_IMPLEMENTATION_PARNEW_PARGCALLOCBUFFER_HPP
-
-#include "gc_implementation/shared/gcUtil.hpp"
-#include "memory/allocation.hpp"
-#include "runtime/atomic.hpp"
-#include "utilities/globalDefinitions.hpp"
-
-// Forward declarations.
-class PLABStats;
-
-// A per-thread allocation buffer used during GC.
-class ParGCAllocBuffer: public CHeapObj<mtGC> {
-protected:
-  char      head[32];
-  size_t    _word_sz;          // In HeapWord units
-  HeapWord* _bottom;
-  HeapWord* _top;
-  HeapWord* _end;           // Last allocatable address + 1
-  HeapWord* _hard_end;      // _end + AlignmentReserve
-  // In support of ergonomic sizing of PLAB's
-  size_t    _allocated;     // in HeapWord units
-  size_t    _wasted;        // in HeapWord units
-  char      tail[32];
-  static size_t AlignmentReserve;
-
-  // Force future allocations to fail and queries for contains()
-  // to return false. Returns the amount of unused space in this PLAB.
-  size_t invalidate() {
-    _end    = _hard_end;
-    size_t remaining = pointer_delta(_end, _top);  // Calculate remaining space.
-    _top    = _end;      // Force future allocations to fail.
-    _bottom = _end;      // Force future contains() queries to return false.
-    return remaining;
-  }
-
-  // Fill in remaining space with a dummy object and invalidate the PLAB. Returns
-  // the amount of remaining space.
-  size_t retire_internal();
-
-public:
-  // Initializes the buffer to be empty, but with the given "word_sz".
-  // Must get initialized with "set_buf" for an allocation to succeed.
-  ParGCAllocBuffer(size_t word_sz);
-  virtual ~ParGCAllocBuffer() {}
-
-  // Minimum PLAB size.
-  static size_t min_size();
-  // Maximum PLAB size.
-  static size_t max_size();
-
-  // If an allocation of the given "word_sz" can be satisfied within the
-  // buffer, do the allocation, returning a pointer to the start of the
-  // allocated block.  If the allocation request cannot be satisfied,
-  // return NULL.
-  HeapWord* allocate(size_t word_sz) {
-    HeapWord* res = _top;
-    if (pointer_delta(_end, _top) >= word_sz) {
-      _top = _top + word_sz;
-      return res;
-    } else {
-      return NULL;
-    }
-  }
-
-  // Allocate the object aligned to "alignment_in_bytes".
-  HeapWord* allocate_aligned(size_t word_sz, unsigned short alignment_in_bytes);
-
-  // Undo the last allocation in the buffer, which is required to be of the
-  // "obj" of the given "word_sz".
-  void undo_allocation(HeapWord* obj, size_t word_sz) {
-    assert(pointer_delta(_top, _bottom) >= word_sz, "Bad undo");
-    assert(pointer_delta(_top, obj)     == word_sz, "Bad undo");
-    _top = obj;
-  }
-
-  // The total (word) size of the buffer, including both allocated and
-  // unallocated space.
-  size_t word_sz() { return _word_sz; }
-
-  // Should only be done if we are about to reset with a new buffer of the
-  // given size.
-  void set_word_size(size_t new_word_sz) {
-    assert(new_word_sz > AlignmentReserve, "Too small");
-    _word_sz = new_word_sz;
-  }
-
-  // The number of words of unallocated space remaining in the buffer.
-  size_t words_remaining() {
-    assert(_end >= _top, "Negative buffer");
-    return pointer_delta(_end, _top, HeapWordSize);
-  }
-
-  bool contains(void* addr) {
-    return (void*)_bottom <= addr && addr < (void*)_hard_end;
-  }
-
-  // Sets the space of the buffer to be [buf, space+word_sz()).
-  virtual void set_buf(HeapWord* buf) {
-    _bottom   = buf;
-    _top      = _bottom;
-    _hard_end = _bottom + word_sz();
-    _end      = _hard_end - AlignmentReserve;
-    assert(_end >= _top, "Negative buffer");
-    // In support of ergonomic sizing
-    _allocated += word_sz();
-  }
-
-  // Flush allocation statistics into the given PLABStats supporting ergonomic
-  // sizing of PLAB's and retire the current buffer. To be called at the end of
-  // GC.
-  void flush_and_retire_stats(PLABStats* stats);
-
-  // Fills in the unallocated portion of the buffer with a garbage object and updates
-  // statistics. To be called during GC.
-  virtual void retire();
-
-  void print() PRODUCT_RETURN;
-};
-
-// PLAB book-keeping.
-class PLABStats VALUE_OBJ_CLASS_SPEC {
-  size_t _allocated;      // Total allocated
-  size_t _wasted;         // of which wasted (internal fragmentation)
-  size_t _unused;         // Unused in last buffer
-  size_t _desired_plab_sz;// Output of filter (below), suitably trimmed and quantized
-  AdaptiveWeightedAverage
-         _filter;         // Integrator with decay
-
-  void reset() {
-    _allocated = 0;
-    _wasted    = 0;
-    _unused    = 0;
-  }
- public:
-  PLABStats(size_t desired_plab_sz_, unsigned wt) :
-    _allocated(0),
-    _wasted(0),
-    _unused(0),
-    _desired_plab_sz(desired_plab_sz_),
-    _filter(wt)
-  { }
-
-  static const size_t min_size() {
-    return ParGCAllocBuffer::min_size();
-  }
-
-  static const size_t max_size() {
-    return ParGCAllocBuffer::max_size();
-  }
-
-  size_t desired_plab_sz() {
-    return _desired_plab_sz;
-  }
-
-  // Updates the current desired PLAB size. Computes the new desired PLAB size,
-  // updates _desired_plab_sz and clears sensor accumulators.
-  void adjust_desired_plab_sz(uint no_of_gc_workers);
-
-  void add_allocated(size_t v) {
-    Atomic::add_ptr(v, &_allocated);
-  }
-
-  void add_unused(size_t v) {
-    Atomic::add_ptr(v, &_unused);
-  }
-
-  void add_wasted(size_t v) {
-    Atomic::add_ptr(v, &_wasted);
-  }
-};
-
-#endif // SHARE_VM_GC_IMPLEMENTATION_PARNEW_PARGCALLOCBUFFER_HPP

--- a/hotspot/src/share/vm/gc_implementation/shared/parGCAllocBuffer.inline.hpp	Tue Apr 21 10:29:35 2015 -0400
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,44 +0,0 @@
-/*
- * 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_SHARED_PARGCALLOCBUFFER_INLINE_HPP
-#define SHARE_VM_GC_IMPLEMENTATION_SHARED_PARGCALLOCBUFFER_INLINE_HPP
-
-#include "gc_implementation/shared/parGCAllocBuffer.hpp"
-#include "gc_interface/collectedHeap.inline.hpp"
-
-HeapWord* ParGCAllocBuffer::allocate_aligned(size_t word_sz, unsigned short alignment_in_bytes) {
-
-  HeapWord* res = CollectedHeap::align_allocation_or_fail(_top, _end, alignment_in_bytes);
-  if (res == NULL) {
-    return NULL;
-  }
-
-  // Set _top so that allocate(), which expects _top to be correctly set,
-  // can be used below.
-  _top = res;
-  return allocate(word_sz);
-}
-
-#endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_PARGCALLOCBUFFER_INLINE_HPP

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc_implementation/shared/plab.cpp	Wed Apr 15 11:42:20 2015 -0400
@@ -0,0 +1,134 @@
+/*
+ * Copyright (c) 2001, 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.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "gc_implementation/shared/plab.hpp"
+#include "memory/threadLocalAllocBuffer.hpp"
+#include "oops/arrayOop.hpp"
+#include "oops/oop.inline.hpp"
+
+size_t PLAB::min_size() {
+  // Make sure that we return something that is larger than AlignmentReserve
+  return align_object_size(MAX2(MinTLABSize / HeapWordSize, (uintx)oopDesc::header_size())) + AlignmentReserve;
+}
+
+size_t PLAB::max_size() {
+  return ThreadLocalAllocBuffer::max_size();
+}
+
+PLAB::PLAB(size_t desired_plab_sz_) :
+  _word_sz(desired_plab_sz_), _bottom(NULL), _top(NULL),
+  _end(NULL), _hard_end(NULL), _allocated(0), _wasted(0)
+{
+  // ArrayOopDesc::header_size depends on command line initialization.
+  AlignmentReserve = oopDesc::header_size() > MinObjAlignment ? align_object_size(arrayOopDesc::header_size(T_INT)) : 0;
+  assert(min_size() > AlignmentReserve,
+         err_msg("Minimum PLAB size " SIZE_FORMAT" must be larger than alignment reserve " SIZE_FORMAT" "
+                 "to be able to contain objects", min_size(), AlignmentReserve));
+}
+
+// If the minimum object size is greater than MinObjAlignment, we can
+// end up with a shard at the end of the buffer that's smaller than
+// the smallest object.  We can't allow that because the buffer must
+// look like it's full of objects when we retire it, so we make
+// sure we have enough space for a filler int array object.
+size_t PLAB::AlignmentReserve;
+
+void PLAB::flush_and_retire_stats(PLABStats* stats) {
+  // Retire the last allocation buffer.
+  size_t unused = retire_internal();
+
+  // Now flush the statistics.
+  stats->add_allocated(_allocated);
+  stats->add_wasted(_wasted);
+  stats->add_unused(unused);
+
+  // Since we have flushed the stats we need to clear  the _allocated and _wasted
+  // fields in case somebody retains an instance of this over GCs. Not doing so
+  // will artifically inflate the values in the statistics.
+  _allocated = 0;
+  _wasted = 0;
+}
+
+void PLAB::retire() {
+  _wasted += retire_internal();
+}
+
+size_t PLAB::retire_internal() {
+  size_t result = 0;
+  if (_top < _hard_end) {
+    CollectedHeap::fill_with_object(_top, _hard_end);
+    result += invalidate();
+  }
+  return result;
+}
+
+// Compute desired plab size and latch result for later
+// use. This should be called once at the end of parallel
+// scavenge; it clears the sensor accumulators.
+void PLABStats::adjust_desired_plab_sz(uint no_of_gc_workers) {
+  assert(ResizePLAB, "Not set");
+
+  assert(is_object_aligned(max_size()) && min_size() <= max_size(),
+         "PLAB clipping computation may be incorrect");
+
+  if (_allocated == 0) {
+    assert(_unused == 0,
+           err_msg("Inconsistency in PLAB stats: "
+                   "_allocated: "SIZE_FORMAT", "
+                   "_wasted: "SIZE_FORMAT", "
+                   "_unused: "SIZE_FORMAT,
+                   _allocated, _wasted, _unused));
+
+    _allocated = 1;
+  }
+  double wasted_frac    = (double)_unused / (double)_allocated;
+  size_t target_refills = (size_t)((wasted_frac * TargetSurvivorRatio) / TargetPLABWastePct);
+  if (target_refills == 0) {
+    target_refills = 1;
+  }
+  size_t used = _allocated - _wasted - _unused;
+  size_t recent_plab_sz = used / (target_refills * no_of_gc_workers);
+  // Take historical weighted average
+  _filter.sample(recent_plab_sz);
+  // Clip from above and below, and align to object boundary
+  size_t new_plab_sz = MAX2(min_size(), (size_t)_filter.average());
+  new_plab_sz = MIN2(max_size(), new_plab_sz);
+  new_plab_sz = align_object_size(new_plab_sz);
+  // Latch the result
+  if (PrintPLAB) {
+    gclog_or_tty->print(" (plab_sz = " SIZE_FORMAT" desired_plab_sz = " SIZE_FORMAT") ", recent_plab_sz, new_plab_sz);
+  }
+  _desired_plab_sz = new_plab_sz;
+
+  reset();
+}
+
+#ifndef PRODUCT
+void PLAB::print() {
+  gclog_or_tty->print_cr("PLAB: _bottom: " PTR_FORMAT "  _top: " PTR_FORMAT
+    "  _end: " PTR_FORMAT "  _hard_end: " PTR_FORMAT ")",
+    p2i(_bottom), p2i(_top), p2i(_end), p2i(_hard_end));
+}
+#endif // !PRODUCT

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc_implementation/shared/plab.hpp	Wed Apr 15 11:42:20 2015 -0400
@@ -0,0 +1,197 @@
+/*
+ * Copyright (c) 2001, 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_IMPLEMENTATION_SHARED_PLAB_HPP
+#define SHARE_VM_GC_IMPLEMENTATION_SHARED_PLAB_HPP
+
+#include "gc_implementation/shared/gcUtil.hpp"
+#include "memory/allocation.hpp"
+#include "runtime/atomic.hpp"
+#include "utilities/globalDefinitions.hpp"
+
+// Forward declarations.
+class PLABStats;
+
+// A per-thread allocation buffer used during GC.
+class PLAB: public CHeapObj<mtGC> {
+protected:
+  char      head[32];
+  size_t    _word_sz;          // In HeapWord units
+  HeapWord* _bottom;
+  HeapWord* _top;
+  HeapWord* _end;           // Last allocatable address + 1
+  HeapWord* _hard_end;      // _end + AlignmentReserve
+  // In support of ergonomic sizing of PLAB's
+  size_t    _allocated;     // in HeapWord units
+  size_t    _wasted;        // in HeapWord units
+  char      tail[32];
+  static size_t AlignmentReserve;
+
+  // Force future allocations to fail and queries for contains()
+  // to return false. Returns the amount of unused space in this PLAB.
+  size_t invalidate() {
+    _end    = _hard_end;
+    size_t remaining = pointer_delta(_end, _top);  // Calculate remaining space.
+    _top    = _end;      // Force future allocations to fail.
+    _bottom = _end;      // Force future contains() queries to return false.
+    return remaining;
+  }
+
+  // Fill in remaining space with a dummy object and invalidate the PLAB. Returns
+  // the amount of remaining space.
+  size_t retire_internal();
+
+public:
+  // Initializes the buffer to be empty, but with the given "word_sz".
+  // Must get initialized with "set_buf" for an allocation to succeed.
+  PLAB(size_t word_sz);
+  virtual ~PLAB() {}
+
+  // Minimum PLAB size.
+  static size_t min_size();
+  // Maximum PLAB size.
+  static size_t max_size();
+
+  // If an allocation of the given "word_sz" can be satisfied within the
+  // buffer, do the allocation, returning a pointer to the start of the
+  // allocated block.  If the allocation request cannot be satisfied,
+  // return NULL.
+  HeapWord* allocate(size_t word_sz) {
+    HeapWord* res = _top;
+    if (pointer_delta(_end, _top) >= word_sz) {
+      _top = _top + word_sz;
+      return res;
+    } else {
+      return NULL;
+    }
+  }
+
+  // Allocate the object aligned to "alignment_in_bytes".
+  HeapWord* allocate_aligned(size_t word_sz, unsigned short alignment_in_bytes);
+
+  // Undo the last allocation in the buffer, which is required to be of the
+  // "obj" of the given "word_sz".
+  void undo_allocation(HeapWord* obj, size_t word_sz) {
+    assert(pointer_delta(_top, _bottom) >= word_sz, "Bad undo");
+    assert(pointer_delta(_top, obj)     == word_sz, "Bad undo");
+    _top = obj;
+  }
+
+  // The total (word) size of the buffer, including both allocated and
+  // unallocated space.
+  size_t word_sz() { return _word_sz; }
+
+  // Should only be done if we are about to reset with a new buffer of the
+  // given size.
+  void set_word_size(size_t new_word_sz) {
+    assert(new_word_sz > AlignmentReserve, "Too small");
+    _word_sz = new_word_sz;
+  }
+
+  // The number of words of unallocated space remaining in the buffer.
+  size_t words_remaining() {
+    assert(_end >= _top, "Negative buffer");
+    return pointer_delta(_end, _top, HeapWordSize);
+  }
+
+  bool contains(void* addr) {
+    return (void*)_bottom <= addr && addr < (void*)_hard_end;
+  }
+
+  // Sets the space of the buffer to be [buf, space+word_sz()).
+  virtual void set_buf(HeapWord* buf) {
+    _bottom   = buf;
+    _top      = _bottom;
+    _hard_end = _bottom + word_sz();
+    _end      = _hard_end - AlignmentReserve;
+    assert(_end >= _top, "Negative buffer");
+    // In support of ergonomic sizing
+    _allocated += word_sz();
+  }
+
+  // Flush allocation statistics into the given PLABStats supporting ergonomic
+  // sizing of PLAB's and retire the current buffer. To be called at the end of
+  // GC.
+  void flush_and_retire_stats(PLABStats* stats);
+
+  // Fills in the unallocated portion of the buffer with a garbage object and updates
+  // statistics. To be called during GC.
+  virtual void retire();
+
+  void print() PRODUCT_RETURN;
+};
+
+// PLAB book-keeping.
+class PLABStats VALUE_OBJ_CLASS_SPEC {
+  size_t _allocated;      // Total allocated
+  size_t _wasted;         // of which wasted (internal fragmentation)
+  size_t _unused;         // Unused in last buffer
+  size_t _desired_plab_sz;// Output of filter (below), suitably trimmed and quantized
+  AdaptiveWeightedAverage
+         _filter;         // Integrator with decay
+
+  void reset() {
+    _allocated = 0;
+    _wasted    = 0;
+    _unused    = 0;
+  }
+ public:
+  PLABStats(size_t desired_plab_sz_, unsigned wt) :
+    _allocated(0),
+    _wasted(0),
+    _unused(0),
+    _desired_plab_sz(desired_plab_sz_),
+    _filter(wt)
+  { }
+
+  static const size_t min_size() {
+    return PLAB::min_size();
+  }
+
+  static const size_t max_size() {
+    return PLAB::max_size();
+  }
+
+  size_t desired_plab_sz() {
+    return _desired_plab_sz;
+  }
+
+  // Updates the current desired PLAB size. Computes the new desired PLAB size,
+  // updates _desired_plab_sz and clears sensor accumulators.
+  void adjust_desired_plab_sz(uint no_of_gc_workers);
+
+  void add_allocated(size_t v) {
+    Atomic::add_ptr(v, &_allocated);
+  }
+
+  void add_unused(size_t v) {
+    Atomic::add_ptr(v, &_unused);
+  }
+
+  void add_wasted(size_t v) {
+    Atomic::add_ptr(v, &_wasted);
+  }
+};
+
+#endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_PLAB_HPP

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc_implementation/shared/plab.inline.hpp	Wed Apr 15 11:42:20 2015 -0400
@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2014, 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_IMPLEMENTATION_SHARED_PLAB_INLINE_HPP
+#define SHARE_VM_GC_IMPLEMENTATION_SHARED_PLAB_INLINE_HPP
+
+#include "gc_implementation/shared/plab.hpp"
+#include "gc_interface/collectedHeap.inline.hpp"
+
+HeapWord* PLAB::allocate_aligned(size_t word_sz, unsigned short alignment_in_bytes) {
+
+  HeapWord* res = CollectedHeap::align_allocation_or_fail(_top, _end, alignment_in_bytes);
+  if (res == NULL) {
+    return NULL;
+  }
+
+  // Set _top so that allocate(), which expects _top to be correctly set,
+  // can be used below.
+  _top = res;
+  return allocate(word_sz);
+}
+
+#endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_PLAB_INLINE_HPP

--- a/hotspot/src/share/vm/precompiled/precompiled.hpp	Tue Apr 21 10:29:35 2015 -0400
+++ b/hotspot/src/share/vm/precompiled/precompiled.hpp	Wed Apr 15 11:42:20 2015 -0400
@@ -315,7 +315,7 @@
 # include "gc_implementation/parallelScavenge/psYoungGen.hpp"
 # include "gc_implementation/shared/gcAdaptivePolicyCounters.hpp"
 # include "gc_implementation/shared/gcPolicyCounters.hpp"
-# include "gc_implementation/shared/parGCAllocBuffer.hpp"
+# include "gc_implementation/shared/plab.hpp"
 #endif // INCLUDE_ALL_GCS
 
 #endif // !DONT_USE_PRECOMPILED_HEADER

--- a/hotspot/src/share/vm/runtime/globals.hpp	Tue Apr 21 10:29:35 2015 -0400
+++ b/hotspot/src/share/vm/runtime/globals.hpp	Wed Apr 15 11:42:20 2015 -0400
@@ -1960,7 +1960,7 @@
           "collection")                                                     \
                                                                             \
   develop(uintx, PromotionFailureALotCount, 1000,                           \
-          "Number of promotion failures occurring at ParGCAllocBuffer "     \
+          "Number of promotion failures occurring at PLAB "     \
           "refill attempts (ParNew) or promotion attempts "                 \
           "(other young collectors)")                                       \
                                                                             \