changeset 50882:80abf702eed8

8205683: Refactor heap allocation to separate concerns Reviewed-by: pliden, kbarrett
author eosterlund
date Thu, 28 Jun 2018 14:22:28 +0200
parents a21cad3fa448
children 5d7442ac179a
files src/hotspot/share/classfile/javaClasses.cpp src/hotspot/share/classfile/javaClasses.hpp src/hotspot/share/gc/shared/collectedHeap.cpp src/hotspot/share/gc/shared/collectedHeap.hpp src/hotspot/share/gc/shared/collectedHeap.inline.hpp src/hotspot/share/gc/shared/genCollectedHeap.cpp src/hotspot/share/gc/shared/memAllocator.cpp src/hotspot/share/gc/shared/memAllocator.hpp src/hotspot/share/gc/shared/threadLocalAllocBuffer.cpp src/hotspot/share/gc/shared/threadLocalAllocBuffer.hpp src/hotspot/share/oops/arrayKlass.cpp src/hotspot/share/oops/arrayOop.hpp src/hotspot/share/oops/instanceKlass.cpp src/hotspot/share/oops/instanceMirrorKlass.cpp src/hotspot/share/oops/objArrayKlass.cpp src/hotspot/share/oops/oop.hpp src/hotspot/share/oops/oop.inline.hpp src/hotspot/share/oops/typeArrayKlass.cpp src/hotspot/share/prims/jvm.cpp src/hotspot/share/runtime/interfaceSupport.cpp src/hotspot/share/runtime/threadHeapSampler.cpp src/hotspot/share/runtime/threadHeapSampler.hpp
diffstat 22 files changed, 639 insertions(+), 529 deletions(-) [+]
line wrap: on
line diff
--- a/src/hotspot/share/classfile/javaClasses.cpp	Thu Jun 28 15:17:44 2018 +0200
+++ b/src/hotspot/share/classfile/javaClasses.cpp	Thu Jun 28 14:22:28 2018 +0200
@@ -1265,10 +1265,10 @@
   return size;
 }
 
-void java_lang_Class::set_oop_size(oop java_class, int size) {
+void java_lang_Class::set_oop_size(HeapWord* java_class, int size) {
   assert(_oop_size_offset != 0, "must be set");
   assert(size > 0, "Oop size must be greater than zero, not %d", size);
-  java_class->int_field_put(_oop_size_offset, size);
+  *(int*)(((char*)java_class) + _oop_size_offset) = size;
 }
 
 int  java_lang_Class::static_oop_field_count(oop java_class) {
--- a/src/hotspot/share/classfile/javaClasses.hpp	Thu Jun 28 15:17:44 2018 +0200
+++ b/src/hotspot/share/classfile/javaClasses.hpp	Thu Jun 28 14:22:28 2018 +0200
@@ -270,7 +270,7 @@
   static oop module(oop java_class);
 
   static int oop_size(oop java_class);
-  static void set_oop_size(oop java_class, int size);
+  static void set_oop_size(HeapWord* java_class, int size);
   static int static_oop_field_count(oop java_class);
   static void set_static_oop_field_count(oop java_class, int size);
 
--- a/src/hotspot/share/gc/shared/collectedHeap.cpp	Thu Jun 28 15:17:44 2018 +0200
+++ b/src/hotspot/share/gc/shared/collectedHeap.cpp	Thu Jun 28 14:22:28 2018 +0200
@@ -33,6 +33,7 @@
 #include "gc/shared/gcTrace.hpp"
 #include "gc/shared/gcTraceTime.inline.hpp"
 #include "gc/shared/gcWhen.hpp"
+#include "gc/shared/memAllocator.hpp"
 #include "gc/shared/vmGCOperations.hpp"
 #include "logging/log.hpp"
 #include "memory/metaspace.hpp"
@@ -46,6 +47,7 @@
 #include "runtime/vmThread.hpp"
 #include "services/heapDumper.hpp"
 #include "utilities/align.hpp"
+#include "utilities/copy.hpp"
 
 class ClassLoaderData;
 
@@ -327,15 +329,6 @@
 }
 
 #ifndef PRODUCT
-void CollectedHeap::check_for_bad_heap_word_value(HeapWord* addr, size_t size) {
-  if (CheckMemoryInitialization && ZapUnusedHeapArea) {
-    for (size_t slot = 0; slot < size; slot += 1) {
-      assert((*(intptr_t*) (addr + slot)) != ((intptr_t) badHeapWordVal),
-             "Found badHeapWordValue in post-allocation check");
-    }
-  }
-}
-
 void CollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, size_t size) {
   if (CheckMemoryInitialization && ZapUnusedHeapArea) {
     for (size_t slot = 0; slot < size; slot += 1) {
@@ -346,118 +339,6 @@
 }
 #endif // PRODUCT
 
-#ifdef ASSERT
-void CollectedHeap::check_for_valid_allocation_state() {
-  Thread *thread = Thread::current();
-  // How to choose between a pending exception and a potential
-  // OutOfMemoryError?  Don't allow pending exceptions.
-  // This is a VM policy failure, so how do we exhaustively test it?
-  assert(!thread->has_pending_exception(),
-         "shouldn't be allocating with pending exception");
-  if (StrictSafepointChecks) {
-    assert(thread->allow_allocation(),
-           "Allocation done by thread for which allocation is blocked "
-           "by No_Allocation_Verifier!");
-    // Allocation of an oop can always invoke a safepoint,
-    // hence, the true argument
-    thread->check_for_valid_safepoint_state(true);
-  }
-}
-#endif
-
-HeapWord* CollectedHeap::obj_allocate_raw(Klass* klass, size_t size,
-                                          bool* gc_overhead_limit_was_exceeded, TRAPS) {
-  if (UseTLAB) {
-    HeapWord* result = allocate_from_tlab(klass, size, THREAD);
-    if (result != NULL) {
-      return result;
-    }
-  }
-
-  return allocate_outside_tlab(klass, size, gc_overhead_limit_was_exceeded, THREAD);
-}
-
-HeapWord* CollectedHeap::allocate_from_tlab_slow(Klass* klass, size_t size, TRAPS) {
-  HeapWord* obj = NULL;
-
-  // In assertion mode, check that there was a sampling collector present
-  // in the stack. This enforces checking that no path is without a sampling
-  // collector.
-  // Only check if the sampler could actually sample something in this call path.
-  assert(!JvmtiExport::should_post_sampled_object_alloc()
-         || !JvmtiSampledObjectAllocEventCollector::object_alloc_is_safe_to_sample()
-         || THREAD->heap_sampler().sampling_collector_present(),
-         "Sampling collector not present.");
-
-  if (ThreadHeapSampler::enabled()) {
-    // Try to allocate the sampled object from TLAB, it is possible a sample
-    // point was put and the TLAB still has space.
-    obj = THREAD->tlab().allocate_sampled_object(size);
-
-    if (obj != NULL) {
-      return obj;
-    }
-  }
-
-  ThreadLocalAllocBuffer& tlab = THREAD->tlab();
-
-  // Retain tlab and allocate object in shared space if
-  // the amount free in the tlab is too large to discard.
-  if (tlab.free() > tlab.refill_waste_limit()) {
-    tlab.record_slow_allocation(size);
-    return NULL;
-  }
-
-  // Discard tlab and allocate a new one.
-  // To minimize fragmentation, the last TLAB may be smaller than the rest.
-  size_t new_tlab_size = tlab.compute_size(size);
-
-  tlab.clear_before_allocation();
-
-  if (new_tlab_size == 0) {
-    return NULL;
-  }
-
-  // Allocate a new TLAB requesting new_tlab_size. Any size
-  // between minimal and new_tlab_size is accepted.
-  size_t actual_tlab_size = 0;
-  size_t min_tlab_size = ThreadLocalAllocBuffer::compute_min_size(size);
-  obj = Universe::heap()->allocate_new_tlab(min_tlab_size, new_tlab_size, &actual_tlab_size);
-  if (obj == NULL) {
-    assert(actual_tlab_size == 0, "Allocation failed, but actual size was updated. min: " SIZE_FORMAT ", desired: " SIZE_FORMAT ", actual: " SIZE_FORMAT,
-           min_tlab_size, new_tlab_size, actual_tlab_size);
-    return NULL;
-  }
-  assert(actual_tlab_size != 0, "Allocation succeeded but actual size not updated. obj at: " PTR_FORMAT " min: " SIZE_FORMAT ", desired: " SIZE_FORMAT,
-         p2i(obj), min_tlab_size, new_tlab_size);
-
-  AllocTracer::send_allocation_in_new_tlab(klass, obj, actual_tlab_size * HeapWordSize, size * HeapWordSize, THREAD);
-
-  if (ZeroTLAB) {
-    // ..and clear it.
-    Copy::zero_to_words(obj, actual_tlab_size);
-  } else {
-    // ...and zap just allocated object.
-#ifdef ASSERT
-    // Skip mangling the space corresponding to the object header to
-    // ensure that the returned space is not considered parsable by
-    // any concurrent GC thread.
-    size_t hdr_size = oopDesc::header_size();
-    Copy::fill_to_words(obj + hdr_size, actual_tlab_size - hdr_size, badHeapWordVal);
-#endif // ASSERT
-  }
-
-  // Send the thread information about this allocation in case a sample is
-  // requested.
-  if (ThreadHeapSampler::enabled()) {
-    size_t tlab_bytes_since_last_sample = THREAD->tlab().bytes_since_last_sample_point();
-    THREAD->heap_sampler().check_for_sampling(obj, size, tlab_bytes_since_last_sample);
-  }
-
-  tlab.fill(obj, obj + size, actual_tlab_size);
-  return obj;
-}
-
 size_t CollectedHeap::max_tlab_size() const {
   // TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE].
   // This restriction could be removed by enabling filling with multiple arrays.
@@ -509,9 +390,8 @@
   const size_t len = payload_size * HeapWordSize / sizeof(jint);
   assert((int)len >= 0, "size too large " SIZE_FORMAT " becomes %d", words, (int)len);
 
-  // Set the length first for concurrent GC.
-  ((arrayOop)start)->set_length((int)len);
-  post_allocation_setup_common(Universe::intArrayKlassObj(), start);
+  ObjArrayAllocator allocator(Universe::intArrayKlassObj(), words, (int)len, /* do_zero */ false);
+  allocator.initialize(start);
   DEBUG_ONLY(zap_filler_array(start, words, zap);)
 }
 
@@ -524,7 +404,8 @@
     fill_with_array(start, words, zap);
   } else if (words > 0) {
     assert(words == min_fill_size(), "unaligned size");
-    post_allocation_setup_common(SystemDictionary::Object_klass(), start);
+    ObjAllocator allocator(SystemDictionary::Object_klass(), words);
+    allocator.initialize(start);
   }
 }
 
@@ -566,6 +447,21 @@
   return NULL;
 }
 
+oop CollectedHeap::obj_allocate(Klass* klass, int size, TRAPS) {
+  ObjAllocator allocator(klass, size, THREAD);
+  return allocator.allocate();
+}
+
+oop CollectedHeap::array_allocate(Klass* klass, int size, int length, bool do_zero, TRAPS) {
+  ObjArrayAllocator allocator(klass, size, length, do_zero, THREAD);
+  return allocator.allocate();
+}
+
+oop CollectedHeap::class_allocate(Klass* klass, int size, TRAPS) {
+  ClassAllocator allocator(klass, size, THREAD);
+  return allocator.allocate();
+}
+
 void CollectedHeap::ensure_parsability(bool retire_tlabs) {
   // The second disjunct in the assertion below makes a concession
   // for the start-up verification done while the VM is being
--- a/src/hotspot/share/gc/shared/collectedHeap.hpp	Thu Jun 28 15:17:44 2018 +0200
+++ b/src/hotspot/share/gc/shared/collectedHeap.hpp	Thu Jun 28 14:22:28 2018 +0200
@@ -95,6 +95,7 @@
   friend class VMStructs;
   friend class JVMCIVMStructs;
   friend class IsGCActiveMark; // Block structured external access to _is_gc_active
+  friend class MemAllocator;
 
  private:
 #ifdef ASSERT
@@ -141,13 +142,6 @@
   // Reinitialize tlabs before resuming mutators.
   virtual void resize_all_tlabs();
 
-  // Allocate from the current thread's TLAB, with broken-out slow path.
-  inline static HeapWord* allocate_from_tlab(Klass* klass, size_t size, TRAPS);
-  static HeapWord* allocate_from_tlab_slow(Klass* klass, size_t size, TRAPS);
-
-  inline static HeapWord* allocate_outside_tlab(Klass* klass, size_t size,
-                                                bool* gc_overhead_limit_was_exceeded, TRAPS);
-
   // Raw memory allocation facilities
   // The obj and array allocate methods are covers for these methods.
   // mem_allocate() should never be
@@ -155,29 +149,6 @@
   virtual HeapWord* mem_allocate(size_t size,
                                  bool* gc_overhead_limit_was_exceeded) = 0;
 
-  // Allocate an uninitialized block of the given size, or returns NULL if
-  // this is impossible.
-  inline static HeapWord* common_mem_allocate_noinit(Klass* klass, size_t size, TRAPS);
-
-  // Like allocate_init, but the block returned by a successful allocation
-  // is guaranteed initialized to zeros.
-  inline static HeapWord* common_mem_allocate_init(Klass* klass, size_t size, TRAPS);
-
-  // Helper functions for (VM) allocation.
-  inline static void post_allocation_setup_common(Klass* klass, HeapWord* obj);
-  inline static void post_allocation_setup_no_klass_install(Klass* klass,
-                                                            HeapWord* objPtr);
-
-  inline static void post_allocation_setup_obj(Klass* klass, HeapWord* obj, int size);
-
-  inline static void post_allocation_setup_array(Klass* klass,
-                                                 HeapWord* obj, int length);
-
-  inline static void post_allocation_setup_class(Klass* klass, HeapWord* obj, int size);
-
-  // Clears an allocated object.
-  inline static void init_obj(HeapWord* obj, size_t size);
-
   // Filler object utilities.
   static inline size_t filler_array_hdr_size();
   static inline size_t filler_array_min_size();
@@ -194,21 +165,7 @@
 
   virtual void trace_heap(GCWhen::Type when, const GCTracer* tracer);
 
-  // Internal allocation methods.
-  inline static HeapWord* common_allocate_memory(Klass* klass, int size,
-                                                 void (*post_setup)(Klass*, HeapWord*, int),
-                                                 int size_for_post, bool init_memory,
-                                                 TRAPS);
-
-  // Internal allocation method for common obj/class/array allocations.
-  inline static HeapWord* allocate_memory(Klass* klass, int size,
-                                          void (*post_setup)(Klass*, HeapWord*, int),
-                                          int size_for_post, bool init_memory,
-                                          TRAPS);
-
   // Verification functions
-  virtual void check_for_bad_heap_word_value(HeapWord* addr, size_t size)
-    PRODUCT_RETURN;
   virtual void check_for_non_bad_heap_word_value(HeapWord* addr, size_t size)
     PRODUCT_RETURN;
   debug_only(static void check_for_valid_allocation_state();)
@@ -328,18 +285,9 @@
   }
   GCCause::Cause gc_cause() { return _gc_cause; }
 
-  // General obj/array allocation facilities.
-  inline static oop obj_allocate(Klass* klass, int size, TRAPS);
-  inline static oop array_allocate(Klass* klass, int size, int length, TRAPS);
-  inline static oop array_allocate_nozero(Klass* klass, int size, int length, TRAPS);
-  inline static oop class_allocate(Klass* klass, int size, TRAPS);
-
-  // Raw memory allocation. This may or may not use TLAB allocations to satisfy the
-  // allocation. A GC implementation may override this function to satisfy the allocation
-  // in any way. But the default is to try a TLAB allocation, and otherwise perform
-  // mem_allocate.
-  virtual HeapWord* obj_allocate_raw(Klass* klass, size_t size,
-                                     bool* gc_overhead_limit_was_exceeded, TRAPS);
+  virtual oop obj_allocate(Klass* klass, int size, TRAPS);
+  virtual oop array_allocate(Klass* klass, int size, int length, bool do_zero, TRAPS);
+  virtual oop class_allocate(Klass* klass, int size, TRAPS);
 
   // Utilities for turning raw memory into filler objects.
   //
--- a/src/hotspot/share/gc/shared/collectedHeap.inline.hpp	Thu Jun 28 15:17:44 2018 +0200
+++ b/src/hotspot/share/gc/shared/collectedHeap.inline.hpp	Thu Jun 28 14:22:28 2018 +0200
@@ -25,297 +25,9 @@
 #ifndef SHARE_VM_GC_SHARED_COLLECTEDHEAP_INLINE_HPP
 #define SHARE_VM_GC_SHARED_COLLECTEDHEAP_INLINE_HPP
 
-#include "classfile/javaClasses.hpp"
-#include "gc/shared/allocTracer.hpp"
 #include "gc/shared/collectedHeap.hpp"
-#include "gc/shared/threadLocalAllocBuffer.inline.hpp"
-#include "memory/universe.hpp"
-#include "oops/arrayOop.hpp"
 #include "oops/oop.inline.hpp"
-#include "prims/jvmtiExport.hpp"
-#include "runtime/sharedRuntime.hpp"
-#include "runtime/handles.inline.hpp"
-#include "runtime/thread.inline.hpp"
-#include "services/lowMemoryDetector.hpp"
 #include "utilities/align.hpp"
-#include "utilities/copy.hpp"
-
-// Inline allocation implementations.
-
-void CollectedHeap::post_allocation_setup_common(Klass* klass,
-                                                 HeapWord* obj_ptr) {
-  post_allocation_setup_no_klass_install(klass, obj_ptr);
-  oop obj = (oop)obj_ptr;
-#if (INCLUDE_G1GC || INCLUDE_CMSGC)
-  // Need a release store to ensure array/class length, mark word, and
-  // object zeroing are visible before setting the klass non-NULL, for
-  // concurrent collectors.
-  obj->release_set_klass(klass);
-#else
-  obj->set_klass(klass);
-#endif
-}
-
-void CollectedHeap::post_allocation_setup_no_klass_install(Klass* klass,
-                                                           HeapWord* obj_ptr) {
-  oop obj = (oop)obj_ptr;
-
-  assert(obj != NULL, "NULL object pointer");
-  if (UseBiasedLocking && (klass != NULL)) {
-    obj->set_mark_raw(klass->prototype_header());
-  } else {
-    // May be bootstrapping
-    obj->set_mark_raw(markOopDesc::prototype());
-  }
-}
-
-// Support for jvmti and dtrace
-inline void post_allocation_notify(Klass* klass, oop obj, int size) {
-  // support low memory notifications (no-op if not enabled)
-  LowMemoryDetector::detect_low_memory_for_collected_pools();
-
-  // support for JVMTI VMObjectAlloc event (no-op if not enabled)
-  JvmtiExport::vm_object_alloc_event_collector(obj);
-
-  if (DTraceAllocProbes) {
-    // support for Dtrace object alloc event (no-op most of the time)
-    if (klass != NULL && klass->name() != NULL) {
-      SharedRuntime::dtrace_object_alloc(obj, size);
-    }
-  }
-}
-
-void CollectedHeap::post_allocation_setup_obj(Klass* klass,
-                                              HeapWord* obj_ptr,
-                                              int size) {
-  post_allocation_setup_common(klass, obj_ptr);
-  oop obj = (oop)obj_ptr;
-  assert(Universe::is_bootstrapping() ||
-         !obj->is_array(), "must not be an array");
-  // notify jvmti and dtrace
-  post_allocation_notify(klass, obj, size);
-}
-
-void CollectedHeap::post_allocation_setup_class(Klass* klass,
-                                                HeapWord* obj_ptr,
-                                                int size) {
-  // Set oop_size field before setting the _klass field because a
-  // non-NULL _klass field indicates that the object is parsable by
-  // concurrent GC.
-  oop new_cls = (oop)obj_ptr;
-  assert(size > 0, "oop_size must be positive.");
-  java_lang_Class::set_oop_size(new_cls, size);
-  post_allocation_setup_common(klass, obj_ptr);
-  assert(Universe::is_bootstrapping() ||
-         !new_cls->is_array(), "must not be an array");
-  // notify jvmti and dtrace
-  post_allocation_notify(klass, new_cls, size);
-}
-
-void CollectedHeap::post_allocation_setup_array(Klass* klass,
-                                                HeapWord* obj_ptr,
-                                                int length) {
-  // Set array length before setting the _klass field because a
-  // non-NULL klass field indicates that the object is parsable by
-  // concurrent GC.
-  assert(length >= 0, "length should be non-negative");
-  ((arrayOop)obj_ptr)->set_length(length);
-  post_allocation_setup_common(klass, obj_ptr);
-  oop new_obj = (oop)obj_ptr;
-  assert(new_obj->is_array(), "must be an array");
-  // notify jvmti and dtrace (must be after length is set for dtrace)
-  post_allocation_notify(klass, new_obj, new_obj->size());
-}
-
-HeapWord* CollectedHeap::common_mem_allocate_noinit(Klass* klass, size_t size, TRAPS) {
-
-  // Clear unhandled oops for memory allocation.  Memory allocation might
-  // not take out a lock if from tlab, so clear here.
-  CHECK_UNHANDLED_OOPS_ONLY(THREAD->clear_unhandled_oops();)
-
-  if (HAS_PENDING_EXCEPTION) {
-    NOT_PRODUCT(guarantee(false, "Should not allocate with exception pending"));
-    return NULL;  // caller does a CHECK_0 too
-  }
-
-  bool gc_overhead_limit_was_exceeded = false;
-  CollectedHeap* heap = Universe::heap();
-  HeapWord* result = heap->obj_allocate_raw(klass, size, &gc_overhead_limit_was_exceeded, THREAD);
-
-  if (result != NULL) {
-    return result;
-  }
-
-  if (!gc_overhead_limit_was_exceeded) {
-    // -XX:+HeapDumpOnOutOfMemoryError and -XX:OnOutOfMemoryError support
-    report_java_out_of_memory("Java heap space");
-
-    if (JvmtiExport::should_post_resource_exhausted()) {
-      JvmtiExport::post_resource_exhausted(
-        JVMTI_RESOURCE_EXHAUSTED_OOM_ERROR | JVMTI_RESOURCE_EXHAUSTED_JAVA_HEAP,
-        "Java heap space");
-    }
-
-    THROW_OOP_0(Universe::out_of_memory_error_java_heap());
-  } else {
-    // -XX:+HeapDumpOnOutOfMemoryError and -XX:OnOutOfMemoryError support
-    report_java_out_of_memory("GC overhead limit exceeded");
-
-    if (JvmtiExport::should_post_resource_exhausted()) {
-      JvmtiExport::post_resource_exhausted(
-        JVMTI_RESOURCE_EXHAUSTED_OOM_ERROR | JVMTI_RESOURCE_EXHAUSTED_JAVA_HEAP,
-        "GC overhead limit exceeded");
-    }
-
-    THROW_OOP_0(Universe::out_of_memory_error_gc_overhead_limit());
-  }
-}
-
-HeapWord* CollectedHeap::common_mem_allocate_init(Klass* klass, size_t size, TRAPS) {
-  HeapWord* obj = common_mem_allocate_noinit(klass, size, CHECK_NULL);
-  init_obj(obj, size);
-  return obj;
-}
-
-HeapWord* CollectedHeap::allocate_from_tlab(Klass* klass, size_t size, TRAPS) {
-  assert(UseTLAB, "should use UseTLAB");
-
-  HeapWord* obj = THREAD->tlab().allocate(size);
-  if (obj != NULL) {
-    return obj;
-  }
-  // Otherwise...
-  obj = allocate_from_tlab_slow(klass, size, THREAD);
-  assert(obj == NULL || !HAS_PENDING_EXCEPTION,
-         "Unexpected exception, will result in uninitialized storage");
-  return obj;
-}
-
-HeapWord* CollectedHeap::allocate_outside_tlab(Klass* klass, size_t size,
-                                               bool* gc_overhead_limit_was_exceeded, TRAPS) {
-  HeapWord* result = Universe::heap()->mem_allocate(size, gc_overhead_limit_was_exceeded);
-  if (result == NULL) {
-    return result;
-  }
-
-  NOT_PRODUCT(Universe::heap()->check_for_non_bad_heap_word_value(result, size));
-  assert(!HAS_PENDING_EXCEPTION,
-         "Unexpected exception, will result in uninitialized storage");
-  size_t size_in_bytes = size * HeapWordSize;
-  THREAD->incr_allocated_bytes(size_in_bytes);
-
-  AllocTracer::send_allocation_outside_tlab(klass, result, size_in_bytes, THREAD);
-
-  if (ThreadHeapSampler::enabled()) {
-    THREAD->heap_sampler().check_for_sampling(result, size_in_bytes);
-  }
-
-  return result;
-}
-
-void CollectedHeap::init_obj(HeapWord* obj, size_t size) {
-  assert(obj != NULL, "cannot initialize NULL object");
-  const size_t hs = oopDesc::header_size();
-  assert(size >= hs, "unexpected object size");
-  ((oop)obj)->set_klass_gap(0);
-  Copy::fill_to_aligned_words(obj + hs, size - hs);
-}
-
-HeapWord* CollectedHeap::common_allocate_memory(Klass* klass, int size,
-                                                void (*post_setup)(Klass*, HeapWord*, int),
-                                                int size_for_post, bool init_memory,
-                                                TRAPS) {
-  HeapWord* obj;
-  if (init_memory) {
-    obj = common_mem_allocate_init(klass, size, CHECK_NULL);
-  } else {
-    obj = common_mem_allocate_noinit(klass, size, CHECK_NULL);
-  }
-  post_setup(klass, obj, size_for_post);
-  return obj;
-}
-
-HeapWord* CollectedHeap::allocate_memory(Klass* klass, int size,
-                                         void (*post_setup)(Klass*, HeapWord*, int),
-                                         int size_for_post, bool init_memory,
-                                         TRAPS) {
-  HeapWord* obj;
-
-  assert(JavaThread::current()->heap_sampler().add_sampling_collector(),
-         "Should never return false.");
-
-  if (JvmtiExport::should_post_sampled_object_alloc()) {
-    HandleMark hm(THREAD);
-    Handle obj_h;
-    {
-      JvmtiSampledObjectAllocEventCollector collector;
-      obj = common_allocate_memory(klass, size, post_setup, size_for_post,
-                                   init_memory, CHECK_NULL);
-      // If we want to be sampling, protect the allocated object with a Handle
-      // before doing the callback. The callback is done in the destructor of
-      // the JvmtiSampledObjectAllocEventCollector.
-      obj_h = Handle(THREAD, (oop) obj);
-    }
-    obj = (HeapWord*) obj_h();
-  } else {
-    obj = common_allocate_memory(klass, size, post_setup, size_for_post,
-                                 init_memory, CHECK_NULL);
-  }
-
-  assert(JavaThread::current()->heap_sampler().remove_sampling_collector(),
-         "Should never return false.");
-  return obj;
-}
-
-oop CollectedHeap::obj_allocate(Klass* klass, int size, TRAPS) {
-  debug_only(check_for_valid_allocation_state());
-  assert(!Universe::heap()->is_gc_active(), "Allocation during gc not allowed");
-  assert(size >= 0, "int won't convert to size_t");
-  HeapWord* obj = allocate_memory(klass, size, post_allocation_setup_obj,
-                                  size, true, CHECK_NULL);
-  NOT_PRODUCT(Universe::heap()->check_for_bad_heap_word_value(obj, size));
-  return (oop)obj;
-}
-
-oop CollectedHeap::class_allocate(Klass* klass, int size, TRAPS) {
-  debug_only(check_for_valid_allocation_state());
-  assert(!Universe::heap()->is_gc_active(), "Allocation during gc not allowed");
-  assert(size >= 0, "int won't convert to size_t");
-  HeapWord* obj = allocate_memory(klass, size, post_allocation_setup_class,
-                                  size, true, CHECK_NULL);
-  NOT_PRODUCT(Universe::heap()->check_for_bad_heap_word_value(obj, size));
-  return (oop)obj;
-}
-
-oop CollectedHeap::array_allocate(Klass* klass,
-                                  int size,
-                                  int length,
-                                  TRAPS) {
-  debug_only(check_for_valid_allocation_state());
-  assert(!Universe::heap()->is_gc_active(), "Allocation during gc not allowed");
-  assert(size >= 0, "int won't convert to size_t");
-  HeapWord* obj = allocate_memory(klass, size, post_allocation_setup_array,
-                                  length, true, CHECK_NULL);
-  NOT_PRODUCT(Universe::heap()->check_for_bad_heap_word_value(obj, size));
-  return (oop)obj;
-}
-
-oop CollectedHeap::array_allocate_nozero(Klass* klass,
-                                         int size,
-                                         int length,
-                                         TRAPS) {
-  debug_only(check_for_valid_allocation_state());
-  assert(!Universe::heap()->is_gc_active(), "Allocation during gc not allowed");
-  assert(size >= 0, "int won't convert to size_t");
-
-  HeapWord* obj = allocate_memory(klass, size, post_allocation_setup_array,
-                                  length, false, CHECK_NULL);
-#ifndef PRODUCT
-  const size_t hs = oopDesc::header_size()+1;
-  Universe::heap()->check_for_non_bad_heap_word_value(obj+hs, size-hs);
-#endif
-  return (oop)obj;
-}
 
 inline HeapWord* CollectedHeap::align_allocation_or_fail(HeapWord* addr,
                                                          HeapWord* end,
--- a/src/hotspot/share/gc/shared/genCollectedHeap.cpp	Thu Jun 28 15:17:44 2018 +0200
+++ b/src/hotspot/share/gc/shared/genCollectedHeap.cpp	Thu Jun 28 14:22:28 2018 +0200
@@ -275,9 +275,6 @@
 HeapWord* GenCollectedHeap::mem_allocate_work(size_t size,
                                               bool is_tlab,
                                               bool* gc_overhead_limit_was_exceeded) {
-  debug_only(check_for_valid_allocation_state());
-  assert(no_gc_in_progress(), "Allocation during gc not allowed");
-
   // In general gc_overhead_limit_was_exceeded should be false so
   // set it so here and reset it to true only if the gc time
   // limit is being exceeded as checked below.
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/shared/memAllocator.cpp	Thu Jun 28 14:22:28 2018 +0200
@@ -0,0 +1,442 @@
+/*
+ * Copyright (c) 2018, 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 "classfile/javaClasses.hpp"
+#include "gc/shared/allocTracer.hpp"
+#include "gc/shared/collectedHeap.hpp"
+#include "gc/shared/memAllocator.hpp"
+#include "gc/shared/threadLocalAllocBuffer.inline.hpp"
+#include "memory/universe.hpp"
+#include "oops/arrayOop.hpp"
+#include "oops/oop.inline.hpp"
+#include "prims/jvmtiExport.hpp"
+#include "runtime/sharedRuntime.hpp"
+#include "runtime/handles.inline.hpp"
+#include "runtime/thread.inline.hpp"
+#include "services/lowMemoryDetector.hpp"
+#include "utilities/align.hpp"
+#include "utilities/copy.hpp"
+
+class MemAllocator::Allocation: StackObj {
+  friend class MemAllocator;
+
+  const MemAllocator& _allocator;
+  Thread*             _thread;
+  oop*                _obj_ptr;
+  bool                _overhead_limit_exceeded;
+  bool                _allocated_outside_tlab;
+  size_t              _allocated_tlab_size;
+  bool                _tlab_end_reset_for_sample;
+
+  bool check_out_of_memory();
+  void verify_before();
+  void verify_after();
+  void notify_allocation();
+  void notify_allocation_jvmti_allocation_event();
+  void notify_allocation_jvmti_sampler();
+  void notify_allocation_low_memory_detector();
+  void notify_allocation_jfr_sampler();
+  void notify_allocation_dtrace_sampler();
+  void check_for_bad_heap_word_value() const;
+#ifdef ASSERT
+  void check_for_valid_allocation_state() const;
+#endif
+
+  class PreserveObj;
+
+public:
+  Allocation(const MemAllocator& allocator, oop* obj_ptr)
+    : _allocator(allocator),
+      _thread(Thread::current()),
+      _obj_ptr(obj_ptr),
+      _overhead_limit_exceeded(false),
+      _allocated_outside_tlab(false),
+      _allocated_tlab_size(0),
+      _tlab_end_reset_for_sample(false)
+  {
+    verify_before();
+  }
+
+  ~Allocation() {
+    if (!check_out_of_memory()) {
+      verify_after();
+      notify_allocation();
+    }
+  }
+
+  oop obj() const { return *_obj_ptr; }
+};
+
+class MemAllocator::Allocation::PreserveObj: StackObj {
+  HandleMark _handle_mark;
+  Handle     _handle;
+  oop* const _obj_ptr;
+
+public:
+  PreserveObj(Thread* thread, oop* obj_ptr)
+    : _handle_mark(thread),
+      _handle(thread, *obj_ptr),
+      _obj_ptr(obj_ptr)
+  {
+    *obj_ptr = NULL;
+  }
+
+  ~PreserveObj() {
+    *_obj_ptr = _handle();
+  }
+
+  oop operator()() const {
+    return _handle();
+  }
+};
+
+bool MemAllocator::Allocation::check_out_of_memory() {
+  Thread* THREAD = _thread;
+  assert(!HAS_PENDING_EXCEPTION, "Unexpected exception, will result in uninitialized storage");
+
+  if (obj() != NULL) {
+    return false;
+  }
+
+  if (!_overhead_limit_exceeded) {
+    // -XX:+HeapDumpOnOutOfMemoryError and -XX:OnOutOfMemoryError support
+    report_java_out_of_memory("Java heap space");
+
+    if (JvmtiExport::should_post_resource_exhausted()) {
+      JvmtiExport::post_resource_exhausted(
+        JVMTI_RESOURCE_EXHAUSTED_OOM_ERROR | JVMTI_RESOURCE_EXHAUSTED_JAVA_HEAP,
+        "Java heap space");
+    }
+    THROW_OOP_(Universe::out_of_memory_error_java_heap(), true);
+  } else {
+    // -XX:+HeapDumpOnOutOfMemoryError and -XX:OnOutOfMemoryError support
+    report_java_out_of_memory("GC overhead limit exceeded");
+
+    if (JvmtiExport::should_post_resource_exhausted()) {
+      JvmtiExport::post_resource_exhausted(
+        JVMTI_RESOURCE_EXHAUSTED_OOM_ERROR | JVMTI_RESOURCE_EXHAUSTED_JAVA_HEAP,
+        "GC overhead limit exceeded");
+    }
+
+    THROW_OOP_(Universe::out_of_memory_error_gc_overhead_limit(), true);
+  }
+}
+
+void MemAllocator::Allocation::verify_before() {
+  // Clear unhandled oops for memory allocation.  Memory allocation might
+  // not take out a lock if from tlab, so clear here.
+  Thread* THREAD = _thread;
+  CHECK_UNHANDLED_OOPS_ONLY(THREAD->clear_unhandled_oops();)
+  assert(!HAS_PENDING_EXCEPTION, "Should not allocate with exception pending");
+  debug_only(check_for_valid_allocation_state());
+  assert(!Universe::heap()->is_gc_active(), "Allocation during gc not allowed");
+}
+
+void MemAllocator::Allocation::verify_after() {
+  NOT_PRODUCT(check_for_bad_heap_word_value();)
+}
+
+void MemAllocator::Allocation::check_for_bad_heap_word_value() const {
+  MemRegion obj_range = _allocator.obj_memory_range(obj());
+  HeapWord* addr = obj_range.start();
+  size_t size = obj_range.word_size();
+  if (CheckMemoryInitialization && ZapUnusedHeapArea) {
+    for (size_t slot = 0; slot < size; slot += 1) {
+      assert((*(intptr_t*) (addr + slot)) != ((intptr_t) badHeapWordVal),
+             "Found badHeapWordValue in post-allocation check");
+    }
+  }
+}
+
+#ifdef ASSERT
+void MemAllocator::Allocation::check_for_valid_allocation_state() const {
+  // How to choose between a pending exception and a potential
+  // OutOfMemoryError?  Don't allow pending exceptions.
+  // This is a VM policy failure, so how do we exhaustively test it?
+  assert(!_thread->has_pending_exception(),
+         "shouldn't be allocating with pending exception");
+  if (StrictSafepointChecks) {
+    assert(_thread->allow_allocation(),
+           "Allocation done by thread for which allocation is blocked "
+           "by No_Allocation_Verifier!");
+    // Allocation of an oop can always invoke a safepoint,
+    // hence, the true argument
+    _thread->check_for_valid_safepoint_state(true);
+  }
+}
+#endif
+
+void MemAllocator::Allocation::notify_allocation_jvmti_sampler() {
+  // support for JVMTI VMObjectAlloc event (no-op if not enabled)
+  JvmtiExport::vm_object_alloc_event_collector(obj());
+
+  if (!ThreadHeapSampler::enabled()) {
+    // Sampling disabled
+    return;
+  }
+
+  if (!_allocated_outside_tlab && _allocated_tlab_size == 0 && !_tlab_end_reset_for_sample) {
+    // Sample if it's a non-TLAB allocation, or a TLAB allocation that either refills the TLAB
+    // or expands it due to taking a sampler induced slow path.
+    return;
+  }
+
+  assert(JavaThread::current()->heap_sampler().add_sampling_collector(),
+         "Should never return false.");
+
+  // Only check if the sampler could actually sample something in this path.
+  assert(!JvmtiExport::should_post_sampled_object_alloc() ||
+         !JvmtiSampledObjectAllocEventCollector::object_alloc_is_safe_to_sample() ||
+         _thread->heap_sampler().sampling_collector_present(),
+         "Sampling collector not present.");
+
+  if (JvmtiExport::should_post_sampled_object_alloc()) {
+    // If we want to be sampling, protect the allocated object with a Handle
+    // before doing the callback. The callback is done in the destructor of
+    // the JvmtiSampledObjectAllocEventCollector.
+    PreserveObj obj_h(_thread, _obj_ptr);
+    JvmtiSampledObjectAllocEventCollector collector;
+    size_t size_in_bytes = _allocator._word_size * HeapWordSize;
+    ThreadLocalAllocBuffer& tlab = _thread->tlab();
+    size_t bytes_since_last = _allocated_outside_tlab ? 0 : tlab.bytes_since_last_sample_point();
+    _thread->heap_sampler().check_for_sampling(obj_h(), size_in_bytes, bytes_since_last);
+  }
+
+  assert(JavaThread::current()->heap_sampler().remove_sampling_collector(), "Should never return false.");
+
+  if (_tlab_end_reset_for_sample || _allocated_tlab_size != 0) {
+    _thread->tlab().set_sample_end();
+  }
+}
+
+void MemAllocator::Allocation::notify_allocation_low_memory_detector() {
+  // support low memory notifications (no-op if not enabled)
+  LowMemoryDetector::detect_low_memory_for_collected_pools();
+}
+
+void MemAllocator::Allocation::notify_allocation_jfr_sampler() {
+  HeapWord* mem = (HeapWord*)obj();
+  size_t size_in_bytes = _allocator._word_size * HeapWordSize;
+
+  if (_allocated_outside_tlab) {
+    AllocTracer::send_allocation_outside_tlab(_allocator._klass, mem, size_in_bytes, _thread);
+  } else if (_allocated_tlab_size != 0) {
+    // TLAB was refilled
+    AllocTracer::send_allocation_in_new_tlab(_allocator._klass, mem, _allocated_tlab_size * HeapWordSize,
+                                             size_in_bytes, _thread);
+  }
+}
+
+void MemAllocator::Allocation::notify_allocation_dtrace_sampler() {
+  if (DTraceAllocProbes) {
+    // support for Dtrace object alloc event (no-op most of the time)
+    Klass* klass = _allocator._klass;
+    size_t word_size = _allocator._word_size;
+    if (klass != NULL && klass->name() != NULL) {
+      SharedRuntime::dtrace_object_alloc(obj(), (int)word_size);
+    }
+  }
+}
+
+void MemAllocator::Allocation::notify_allocation() {
+  notify_allocation_low_memory_detector();
+  notify_allocation_jfr_sampler();
+  notify_allocation_dtrace_sampler();
+  notify_allocation_jvmti_sampler();
+}
+
+HeapWord* MemAllocator::allocate_outside_tlab(Allocation& allocation) const {
+  allocation._allocated_outside_tlab = true;
+  HeapWord* mem = _heap->mem_allocate(_word_size, &allocation._overhead_limit_exceeded);
+  if (mem == NULL) {
+    return mem;
+  }
+
+  NOT_PRODUCT(_heap->check_for_non_bad_heap_word_value(mem, _word_size));
+  size_t size_in_bytes = _word_size * HeapWordSize;
+  _thread->incr_allocated_bytes(size_in_bytes);
+
+  return mem;
+}
+
+HeapWord* MemAllocator::allocate_inside_tlab(Allocation& allocation) const {
+  assert(UseTLAB, "should use UseTLAB");
+
+  // Try allocating from an existing TLAB.
+  HeapWord* mem = _thread->tlab().allocate(_word_size);
+  if (mem != NULL) {
+    return mem;
+  }
+
+  // Try refilling the TLAB and allocating the object in it.
+  return allocate_inside_tlab_slow(allocation);
+}
+
+HeapWord* MemAllocator::allocate_inside_tlab_slow(Allocation& allocation) const {
+  HeapWord* mem = NULL;
+  ThreadLocalAllocBuffer& tlab = _thread->tlab();
+
+  if (ThreadHeapSampler::enabled()) {
+    // Try to allocate the sampled object from TLAB, it is possible a sample
+    // point was put and the TLAB still has space.
+    tlab.set_back_allocation_end();
+    mem = tlab.allocate(_word_size);
+    if (mem != NULL) {
+      allocation._tlab_end_reset_for_sample = true;
+      return mem;
+    }
+  }
+
+  // Retain tlab and allocate object in shared space if
+  // the amount free in the tlab is too large to discard.
+  if (tlab.free() > tlab.refill_waste_limit()) {
+    tlab.record_slow_allocation(_word_size);
+    return NULL;
+  }
+
+  // Discard tlab and allocate a new one.
+  // To minimize fragmentation, the last TLAB may be smaller than the rest.
+  size_t new_tlab_size = tlab.compute_size(_word_size);
+
+  tlab.clear_before_allocation();
+
+  if (new_tlab_size == 0) {
+    return NULL;
+  }
+
+  // Allocate a new TLAB requesting new_tlab_size. Any size
+  // between minimal and new_tlab_size is accepted.
+  size_t min_tlab_size = ThreadLocalAllocBuffer::compute_min_size(_word_size);
+  mem = _heap->allocate_new_tlab(min_tlab_size, new_tlab_size, &allocation._allocated_tlab_size);
+  if (mem == NULL) {
+    assert(allocation._allocated_tlab_size == 0,
+           "Allocation failed, but actual size was updated. min: " SIZE_FORMAT
+           ", desired: " SIZE_FORMAT ", actual: " SIZE_FORMAT,
+           min_tlab_size, new_tlab_size, allocation._allocated_tlab_size);
+    return NULL;
+  }
+  assert(allocation._allocated_tlab_size != 0, "Allocation succeeded but actual size not updated. mem at: "
+         PTR_FORMAT " min: " SIZE_FORMAT ", desired: " SIZE_FORMAT,
+         p2i(mem), min_tlab_size, new_tlab_size);
+
+  if (ZeroTLAB) {
+    // ..and clear it.
+    Copy::zero_to_words(mem, allocation._allocated_tlab_size);
+  } else {
+    // ...and zap just allocated object.
+#ifdef ASSERT
+    // Skip mangling the space corresponding to the object header to
+    // ensure that the returned space is not considered parsable by
+    // any concurrent GC thread.
+    size_t hdr_size = oopDesc::header_size();
+    Copy::fill_to_words(mem + hdr_size, allocation._allocated_tlab_size - hdr_size, badHeapWordVal);
+#endif // ASSERT
+  }
+
+  tlab.fill(mem, mem + _word_size, allocation._allocated_tlab_size);
+  return mem;
+}
+
+HeapWord* MemAllocator::mem_allocate(Allocation& allocation) const {
+  if (UseTLAB) {
+    HeapWord* result = allocate_inside_tlab(allocation);
+    if (result != NULL) {
+      return result;
+    }
+  }
+
+  return allocate_outside_tlab(allocation);
+}
+
+oop MemAllocator::allocate() const {
+  oop obj = NULL;
+  {
+    Allocation allocation(*this, &obj);
+    HeapWord* mem = mem_allocate(allocation);
+    if (mem != NULL) {
+      obj = initialize(mem);
+    }
+  }
+  return obj;
+}
+
+void MemAllocator::mem_clear(HeapWord* mem) const {
+  assert(mem != NULL, "cannot initialize NULL object");
+  const size_t hs = oopDesc::header_size();
+  assert(_word_size >= hs, "unexpected object size");
+  oopDesc::set_klass_gap(mem, 0);
+  Copy::fill_to_aligned_words(mem + hs, _word_size - hs);
+}
+
+oop MemAllocator::finish(HeapWord* mem) const {
+  assert(mem != NULL, "NULL object pointer");
+  if (UseBiasedLocking) {
+    oopDesc::set_mark_raw(mem, _klass->prototype_header());
+  } else {
+    // May be bootstrapping
+    oopDesc::set_mark_raw(mem, markOopDesc::prototype());
+  }
+  // Need a release store to ensure array/class length, mark word, and
+  // object zeroing are visible before setting the klass non-NULL, for
+  // concurrent collectors.
+  oopDesc::release_set_klass(mem, _klass);
+  return oop(mem);
+}
+
+oop ObjAllocator::initialize(HeapWord* mem) const {
+  mem_clear(mem);
+  return finish(mem);
+}
+
+MemRegion ObjArrayAllocator::obj_memory_range(oop obj) const {
+  if (_do_zero) {
+    return MemAllocator::obj_memory_range(obj);
+  }
+  ArrayKlass* array_klass = ArrayKlass::cast(_klass);
+  const size_t hs = arrayOopDesc::header_size(array_klass->element_type());
+  return MemRegion(((HeapWord*)obj) + hs, _word_size - hs);
+}
+
+oop ObjArrayAllocator::initialize(HeapWord* mem) const {
+  // Set array length before setting the _klass field because a
+  // non-NULL klass field indicates that the object is parsable by
+  // concurrent GC.
+  assert(_length >= 0, "length should be non-negative");
+  if (_do_zero) {
+    mem_clear(mem);
+  }
+  arrayOopDesc::set_length(mem, _length);
+  return finish(mem);
+}
+
+oop ClassAllocator::initialize(HeapWord* mem) const {
+  // Set oop_size field before setting the _klass field because a
+  // non-NULL _klass field indicates that the object is parsable by
+  // concurrent GC.
+  assert(_word_size > 0, "oop_size must be positive.");
+  mem_clear(mem);
+  java_lang_Class::set_oop_size(mem, (int)_word_size);
+  return finish(mem);
+}
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/shared/memAllocator.hpp	Thu Jun 28 14:22:28 2018 +0200
@@ -0,0 +1,110 @@
+/*
+ * Copyright (c) 2018, 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_GC_SHARED_MEM_ALLOCATOR_HPP
+#define SHARE_GC_SHARED_MEM_ALLOCATOR_HPP
+
+#include "gc/shared/collectedHeap.hpp"
+#include "memory/memRegion.hpp"
+#include "oops/oopsHierarchy.hpp"
+#include "utilities/exceptions.hpp"
+#include "utilities/macros.hpp"
+
+// These fascilities are used for allocating, and initializing newly allocated objects.
+
+class MemAllocator: StackObj {
+  class Allocation;
+
+protected:
+  CollectedHeap* const _heap;
+  Thread* const        _thread;
+  Klass* const         _klass;
+  const size_t         _word_size;
+
+private:
+  // Allocate from the current thread's TLAB, with broken-out slow path.
+  HeapWord* allocate_inside_tlab(Allocation& allocation) const;
+  HeapWord* allocate_inside_tlab_slow(Allocation& allocation) const;
+  HeapWord* allocate_outside_tlab(Allocation& allocation) const;
+
+protected:
+  MemAllocator(Klass* klass, size_t word_size, Thread* thread)
+    : _heap(Universe::heap()),
+      _thread(thread),
+      _klass(klass),
+      _word_size(word_size)
+  { }
+
+  // This function clears the memory of the object
+  void mem_clear(HeapWord* mem) const;
+  // This finish constructing an oop by installing the mark word and the Klass* pointer
+  // last. At the point when the Klass pointer is initialized, this is a constructed object
+  // that must be parseable as an oop by concurrent collectors.
+  oop finish(HeapWord* mem) const;
+
+  // Raw memory allocation. This may or may not use TLAB allocations to satisfy the
+  // allocation. A GC implementation may override this function to satisfy the allocation
+  // in any way. But the default is to try a TLAB allocation, and otherwise perform
+  // mem_allocate.
+  virtual HeapWord* mem_allocate(Allocation& allocation) const;
+
+  virtual MemRegion obj_memory_range(oop obj) const {
+    return MemRegion((HeapWord*)obj, _word_size);
+  }
+
+public:
+  oop allocate() const;
+  virtual oop initialize(HeapWord* mem) const = 0;
+};
+
+class ObjAllocator: public MemAllocator {
+public:
+  ObjAllocator(Klass* klass, size_t word_size, Thread* thread = Thread::current())
+    : MemAllocator(klass, word_size, thread) {}
+  virtual oop initialize(HeapWord* mem) const;
+};
+
+class ObjArrayAllocator: public MemAllocator {
+  const int  _length;
+  const bool _do_zero;
+protected:
+  virtual MemRegion obj_memory_range(oop obj) const;
+
+public:
+  ObjArrayAllocator(Klass* klass, size_t word_size, int length, bool do_zero,
+                    Thread* thread = Thread::current())
+    : MemAllocator(klass, word_size, thread),
+      _length(length),
+      _do_zero(do_zero) {}
+  virtual oop initialize(HeapWord* mem) const;
+};
+
+class ClassAllocator: public MemAllocator {
+public:
+  ClassAllocator(Klass* klass, size_t word_size, Thread* thread = Thread::current())
+    : MemAllocator(klass, word_size, thread) {}
+  virtual oop initialize(HeapWord* mem) const;
+};
+
+#endif // SHARE_GC_SHARED_MEM_ALLOCATOR_HPP
--- a/src/hotspot/share/gc/shared/threadLocalAllocBuffer.cpp	Thu Jun 28 15:17:44 2018 +0200
+++ b/src/hotspot/share/gc/shared/threadLocalAllocBuffer.cpp	Thu Jun 28 14:22:28 2018 +0200
@@ -185,10 +185,6 @@
 
   initialize(start, top, start + new_size - alignment_reserve());
 
-  if (ThreadHeapSampler::enabled()) {
-    set_sample_end();
-  }
-
   // Reset amount of internal fragmentation
   set_refill_waste_limit(initial_refill_waste_limit());
 }
@@ -325,14 +321,14 @@
 void ThreadLocalAllocBuffer::set_sample_end() {
   size_t heap_words_remaining = pointer_delta(_end, _top);
   size_t bytes_until_sample = myThread()->heap_sampler().bytes_until_sample();
-  size_t words_until_sample = bytes_until_sample / HeapWordSize;;
+  size_t words_until_sample = bytes_until_sample / HeapWordSize;
 
   if (heap_words_remaining > words_until_sample) {
     HeapWord* new_end = _top + words_until_sample;
     set_end(new_end);
     _bytes_since_last_sample_point = bytes_until_sample;
   } else {
-    _bytes_since_last_sample_point = heap_words_remaining * HeapWordSize;;
+    _bytes_since_last_sample_point = heap_words_remaining * HeapWordSize;
   }
 }
 
@@ -346,18 +342,6 @@
   _end = _allocation_end;
 }
 
-HeapWord* ThreadLocalAllocBuffer::allocate_sampled_object(size_t size) {
-  set_back_allocation_end();
-  HeapWord* result = allocate(size);
-
-  if (result) {
-    myThread()->heap_sampler().check_for_sampling(result, size * HeapWordSize, _bytes_since_last_sample_point);
-    set_sample_end();
-  }
-
-  return result;
-}
-
 HeapWord* ThreadLocalAllocBuffer::hard_end() {
   return _allocation_end + alignment_reserve();
 }
--- a/src/hotspot/share/gc/shared/threadLocalAllocBuffer.hpp	Thu Jun 28 15:17:44 2018 +0200
+++ b/src/hotspot/share/gc/shared/threadLocalAllocBuffer.hpp	Thu Jun 28 14:22:28 2018 +0200
@@ -139,7 +139,6 @@
 
   // Allocate size HeapWords. The memory is NOT initialized to zero.
   inline HeapWord* allocate(size_t size);
-  HeapWord* allocate_sampled_object(size_t size);
 
   // Reserve space at the end of TLAB
   static size_t end_reserve() {
--- a/src/hotspot/share/oops/arrayKlass.cpp	Thu Jun 28 15:17:44 2018 +0200
+++ b/src/hotspot/share/oops/arrayKlass.cpp	Thu Jun 28 14:22:28 2018 +0200
@@ -142,8 +142,8 @@
   int size = objArrayOopDesc::object_size(length);
   Klass* k = array_klass(n+dimension(), CHECK_0);
   ArrayKlass* ak = ArrayKlass::cast(k);
-  objArrayOop o =
-    (objArrayOop)CollectedHeap::array_allocate(ak, size, length, CHECK_0);
+  objArrayOop o = (objArrayOop)Universe::heap()->array_allocate(ak, size, length,
+                                                                /* do_zero */ true, CHECK_0);
   // initialization to NULL not necessary, area already cleared
   return o;
 }
--- a/src/hotspot/share/oops/arrayOop.hpp	Thu Jun 28 15:17:44 2018 +0200
+++ b/src/hotspot/share/oops/arrayOop.hpp	Thu Jun 28 14:22:28 2018 +0200
@@ -109,7 +109,10 @@
     return *(int*)(((intptr_t)this) + length_offset_in_bytes());
   }
   void set_length(int length) {
-    *(int*)(((intptr_t)this) + length_offset_in_bytes()) = length;
+    set_length((HeapWord*)this, length);
+  }
+  static void set_length(HeapWord* mem, int length) {
+    *(int*)(((char*)mem) + length_offset_in_bytes()) = length;
   }
 
   // Should only be called with constants as argument
--- a/src/hotspot/share/oops/instanceKlass.cpp	Thu Jun 28 15:17:44 2018 +0200
+++ b/src/hotspot/share/oops/instanceKlass.cpp	Thu Jun 28 14:22:28 2018 +0200
@@ -1184,8 +1184,8 @@
   }
   int size = objArrayOopDesc::object_size(length);
   Klass* ak = array_klass(n, CHECK_NULL);
-  objArrayOop o =
-    (objArrayOop)CollectedHeap::array_allocate(ak, size, length, CHECK_NULL);
+  objArrayOop o = (objArrayOop)Universe::heap()->array_allocate(ak, size, length,
+                                                                /* do_zero */ true, CHECK_NULL);
   return o;
 }
 
@@ -1210,7 +1210,7 @@
 
   instanceOop i;
 
-  i = (instanceOop)CollectedHeap::obj_allocate(this, size, CHECK_NULL);
+  i = (instanceOop)Universe::heap()->obj_allocate(this, size, CHECK_NULL);
   if (has_finalizer_flag && !RegisterFinalizersAtInit) {
     i = register_finalizer(i, CHECK_NULL);
   }
--- a/src/hotspot/share/oops/instanceMirrorKlass.cpp	Thu Jun 28 15:17:44 2018 +0200
+++ b/src/hotspot/share/oops/instanceMirrorKlass.cpp	Thu Jun 28 14:22:28 2018 +0200
@@ -52,7 +52,7 @@
 
   // Since mirrors can be variable sized because of the static fields, store
   // the size in the mirror itself.
-  return (instanceOop)CollectedHeap::class_allocate(this, size, CHECK_NULL);
+  return (instanceOop)Universe::heap()->class_allocate(this, size, CHECK_NULL);
 }
 
 int InstanceMirrorKlass::oop_size(oop obj) const {
--- a/src/hotspot/share/oops/objArrayKlass.cpp	Thu Jun 28 15:17:44 2018 +0200
+++ b/src/hotspot/share/oops/objArrayKlass.cpp	Thu Jun 28 14:22:28 2018 +0200
@@ -173,7 +173,8 @@
   if (length >= 0) {
     if (length <= arrayOopDesc::max_array_length(T_OBJECT)) {
       int size = objArrayOopDesc::object_size(length);
-      return (objArrayOop)CollectedHeap::array_allocate(this, size, length, THREAD);
+      return (objArrayOop)Universe::heap()->array_allocate(this, size, length,
+                                                           /* do_zero */ true, THREAD);
     } else {
       report_java_out_of_memory("Requested array size exceeds VM limit");
       JvmtiExport::post_array_size_exhausted();
--- a/src/hotspot/share/oops/oop.hpp	Thu Jun 28 15:17:44 2018 +0200
+++ b/src/hotspot/share/oops/oop.hpp	Thu Jun 28 14:22:28 2018 +0200
@@ -69,6 +69,7 @@
 
   inline void set_mark(volatile markOop m);
   inline void set_mark_raw(volatile markOop m);
+  static inline void set_mark_raw(HeapWord* mem, markOop m);
 
   inline void release_set_mark(markOop m);
   inline markOop cas_set_mark(markOop new_mark, markOop old_mark);
@@ -82,15 +83,18 @@
   inline Klass* klass() const;
   inline Klass* klass_or_null() const volatile;
   inline Klass* klass_or_null_acquire() const volatile;
+  static inline Klass** klass_addr(HeapWord* mem);
+  static inline narrowKlass* compressed_klass_addr(HeapWord* mem);
   inline Klass** klass_addr();
   inline narrowKlass* compressed_klass_addr();
 
   inline void set_klass(Klass* k);
-  inline void release_set_klass(Klass* k);
+  static inline void release_set_klass(HeapWord* mem, Klass* klass);
 
   // For klass field compression
   inline int klass_gap() const;
   inline void set_klass_gap(int z);
+  static inline void set_klass_gap(HeapWord* mem, int z);
   // For when the klass pointer is being used as a linked list "next" field.
   inline void set_klass_to_list_ptr(oop k);
   inline oop list_ptr_from_klass();
--- a/src/hotspot/share/oops/oop.inline.hpp	Thu Jun 28 15:17:44 2018 +0200
+++ b/src/hotspot/share/oops/oop.inline.hpp	Thu Jun 28 14:22:28 2018 +0200
@@ -63,6 +63,10 @@
   _mark = m;
 }
 
+void oopDesc::set_mark_raw(HeapWord* mem, markOop m) {
+  *(markOop*)(((char*)mem) + mark_offset_in_bytes()) = m;
+}
+
 void oopDesc::release_set_mark(markOop m) {
   HeapAccess<MO_RELEASE>::store_at(as_oop(), mark_offset_in_bytes(), m);
 }
@@ -110,16 +114,26 @@
   }
 }
 
-Klass** oopDesc::klass_addr() {
+Klass** oopDesc::klass_addr(HeapWord* mem) {
   // Only used internally and with CMS and will not work with
   // UseCompressedOops
   assert(!UseCompressedClassPointers, "only supported with uncompressed klass pointers");
-  return (Klass**) &_metadata._klass;
+  ByteSize offset = byte_offset_of(oopDesc, _metadata._klass);
+  return (Klass**) (((char*)mem) + in_bytes(offset));
+}
+
+narrowKlass* oopDesc::compressed_klass_addr(HeapWord* mem) {
+  assert(UseCompressedClassPointers, "only called by compressed klass pointers");
+  ByteSize offset = byte_offset_of(oopDesc, _metadata._compressed_klass);
+  return (narrowKlass*) (((char*)mem) + in_bytes(offset));
+}
+
+Klass** oopDesc::klass_addr() {
+  return klass_addr((HeapWord*)this);
 }
 
 narrowKlass* oopDesc::compressed_klass_addr() {
-  assert(UseCompressedClassPointers, "only called by compressed klass pointers");
-  return &_metadata._compressed_klass;
+  return compressed_klass_addr((HeapWord*)this);
 }
 
 #define CHECK_SET_KLASS(k)                                                \
@@ -137,13 +151,13 @@
   }
 }
 
-void oopDesc::release_set_klass(Klass* k) {
-  CHECK_SET_KLASS(k);
+void oopDesc::release_set_klass(HeapWord* mem, Klass* klass) {
+  CHECK_SET_KLASS(klass);
   if (UseCompressedClassPointers) {
-    OrderAccess::release_store(compressed_klass_addr(),
-                               Klass::encode_klass_not_null(k));
+    OrderAccess::release_store(compressed_klass_addr(mem),
+                               Klass::encode_klass_not_null(klass));
   } else {
-    OrderAccess::release_store(klass_addr(), k);
+    OrderAccess::release_store(klass_addr(mem), klass);
   }
 }
 
@@ -153,10 +167,14 @@
   return *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes());
 }
 
+void oopDesc::set_klass_gap(HeapWord* mem, int v) {
+  if (UseCompressedClassPointers) {
+    *(int*)(((char*)mem) + klass_gap_offset_in_bytes()) = v;
+  }
+}
+
 void oopDesc::set_klass_gap(int v) {
-  if (UseCompressedClassPointers) {
-    *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes()) = v;
-  }
+  set_klass_gap((HeapWord*)this, v);
 }
 
 void oopDesc::set_klass_to_list_ptr(oop k) {
--- a/src/hotspot/share/oops/typeArrayKlass.cpp	Thu Jun 28 15:17:44 2018 +0200
+++ b/src/hotspot/share/oops/typeArrayKlass.cpp	Thu Jun 28 14:22:28 2018 +0200
@@ -102,14 +102,8 @@
   if (length >= 0) {
     if (length <= max_length()) {
       size_t size = typeArrayOopDesc::object_size(layout_helper(), length);
-      typeArrayOop t;
-      CollectedHeap* ch = Universe::heap();
-      if (do_zero) {
-        t = (typeArrayOop)CollectedHeap::array_allocate(this, (int)size, length, CHECK_NULL);
-      } else {
-        t = (typeArrayOop)CollectedHeap::array_allocate_nozero(this, (int)size, length, CHECK_NULL);
-      }
-      return t;
+      return (typeArrayOop)Universe::heap()->array_allocate(this, (int)size, length,
+                                                            do_zero, CHECK_NULL);
     } else {
       report_java_out_of_memory("Requested array size exceeds VM limit");
       JvmtiExport::post_array_size_exhausted();
--- a/src/hotspot/share/prims/jvm.cpp	Thu Jun 28 15:17:44 2018 +0200
+++ b/src/hotspot/share/prims/jvm.cpp	Thu Jun 28 14:22:28 2018 +0200
@@ -38,6 +38,7 @@
 #include "gc/shared/collectedHeap.inline.hpp"
 #include "interpreter/bytecode.hpp"
 #include "jfr/jfrEvents.hpp"
+#include "logging/log.hpp"
 #include "memory/oopFactory.hpp"
 #include "memory/referenceType.hpp"
 #include "memory/resourceArea.hpp"
@@ -661,9 +662,10 @@
   oop new_obj_oop = NULL;
   if (obj->is_array()) {
     const int length = ((arrayOop)obj())->length();
-    new_obj_oop = CollectedHeap::array_allocate(klass, size, length, CHECK_NULL);
+    new_obj_oop = Universe::heap()->array_allocate(klass, size, length,
+                                                   /* do_zero */ true, CHECK_NULL);
   } else {
-    new_obj_oop = CollectedHeap::obj_allocate(klass, size, CHECK_NULL);
+    new_obj_oop = Universe::heap()->obj_allocate(klass, size, CHECK_NULL);
   }
 
   HeapAccess<>::clone(obj(), new_obj_oop, size);
--- a/src/hotspot/share/runtime/interfaceSupport.cpp	Thu Jun 28 15:17:44 2018 +0200
+++ b/src/hotspot/share/runtime/interfaceSupport.cpp	Thu Jun 28 14:22:28 2018 +0200
@@ -25,6 +25,7 @@
 #include "precompiled.hpp"
 #include "gc/shared/collectedHeap.hpp"
 #include "gc/shared/collectedHeap.inline.hpp"
+#include "logging/log.hpp"
 #include "memory/resourceArea.hpp"
 #include "runtime/atomic.hpp"
 #include "runtime/frame.inline.hpp"
--- a/src/hotspot/share/runtime/threadHeapSampler.cpp	Thu Jun 28 15:17:44 2018 +0200
+++ b/src/hotspot/share/runtime/threadHeapSampler.cpp	Thu Jun 28 14:22:28 2018 +0200
@@ -116,8 +116,7 @@
   }
 }
 
-void ThreadHeapSampler::check_for_sampling(HeapWord* ptr, size_t allocation_size, size_t bytes_since_allocation) {
-  oopDesc* oop = reinterpret_cast<oopDesc*>(ptr);
+void ThreadHeapSampler::check_for_sampling(oop obj, size_t allocation_size, size_t bytes_since_allocation) {
   size_t total_allocated_bytes = bytes_since_allocation + allocation_size;
 
   // If not yet time for a sample, skip it.
@@ -126,7 +125,7 @@
     return;
   }
 
-  JvmtiExport::sampled_object_alloc_event_collector(oop);
+  JvmtiExport::sampled_object_alloc_event_collector(obj);
 
   size_t overflow_bytes = total_allocated_bytes - _bytes_until_sample;
   pick_next_sample(overflow_bytes);
--- a/src/hotspot/share/runtime/threadHeapSampler.hpp	Thu Jun 28 15:17:44 2018 +0200
+++ b/src/hotspot/share/runtime/threadHeapSampler.hpp	Thu Jun 28 14:22:28 2018 +0200
@@ -57,7 +57,7 @@
   size_t bytes_until_sample()                    { return _bytes_until_sample;   }
   void set_bytes_until_sample(size_t bytes)      { _bytes_until_sample = bytes;  }
 
-  void check_for_sampling(HeapWord* obj, size_t size_in_bytes, size_t bytes_allocated_before = 0);
+  void check_for_sampling(oop obj, size_t size_in_bytes, size_t bytes_allocated_before);
 
   static int enabled();
   static void enable();