--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/gc_implementation/parallelScavenge/parallelScavengeHeap.cpp	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,909 @@
+/*
+ * Copyright 2001-2007 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+# include "incls/_precompiled.incl"
+# include "incls/_parallelScavengeHeap.cpp.incl"
+
+PSYoungGen*  ParallelScavengeHeap::_young_gen = NULL;
+PSOldGen*    ParallelScavengeHeap::_old_gen = NULL;
+PSPermGen*   ParallelScavengeHeap::_perm_gen = NULL;
+PSAdaptiveSizePolicy* ParallelScavengeHeap::_size_policy = NULL;
+PSGCAdaptivePolicyCounters* ParallelScavengeHeap::_gc_policy_counters = NULL;
+ParallelScavengeHeap* ParallelScavengeHeap::_psh = NULL;
+GCTaskManager* ParallelScavengeHeap::_gc_task_manager = NULL;
+
+static void trace_gen_sizes(const char* const str,
+                            size_t pg_min, size_t pg_max,
+                            size_t og_min, size_t og_max,
+                            size_t yg_min, size_t yg_max)
+{
+  if (TracePageSizes) {
+    tty->print_cr("%s:  " SIZE_FORMAT "," SIZE_FORMAT " "
+                  SIZE_FORMAT "," SIZE_FORMAT " "
+                  SIZE_FORMAT "," SIZE_FORMAT " "
+                  SIZE_FORMAT,
+                  str, pg_min / K, pg_max / K,
+                  og_min / K, og_max / K,
+                  yg_min / K, yg_max / K,
+                  (pg_max + og_max + yg_max) / K);
+  }
+}
+
+jint ParallelScavengeHeap::initialize() {
+  // Cannot be initialized until after the flags are parsed
+  GenerationSizer flag_parser;
+
+  size_t yg_min_size = flag_parser.min_young_gen_size();
+  size_t yg_max_size = flag_parser.max_young_gen_size();
+  size_t og_min_size = flag_parser.min_old_gen_size();
+  size_t og_max_size = flag_parser.max_old_gen_size();
+  // Why isn't there a min_perm_gen_size()?
+  size_t pg_min_size = flag_parser.perm_gen_size();
+  size_t pg_max_size = flag_parser.max_perm_gen_size();
+
+  trace_gen_sizes("ps heap raw",
+                  pg_min_size, pg_max_size,
+                  og_min_size, og_max_size,
+                  yg_min_size, yg_max_size);
+
+  // The ReservedSpace ctor used below requires that the page size for the perm
+  // gen is <= the page size for the rest of the heap (young + old gens).
+  const size_t og_page_sz = os::page_size_for_region(yg_min_size + og_min_size,
+                                                     yg_max_size + og_max_size,
+                                                     8);
+  const size_t pg_page_sz = MIN2(os::page_size_for_region(pg_min_size,
+                                                          pg_max_size, 16),
+                                 og_page_sz);
+
+  const size_t pg_align = set_alignment(_perm_gen_alignment,  pg_page_sz);
+  const size_t og_align = set_alignment(_old_gen_alignment,   og_page_sz);
+  const size_t yg_align = set_alignment(_young_gen_alignment, og_page_sz);
+
+  // Update sizes to reflect the selected page size(s).
+  //
+  // NEEDS_CLEANUP.  The default TwoGenerationCollectorPolicy uses NewRatio; it
+  // should check UseAdaptiveSizePolicy.  Changes from generationSizer could
+  // move to the common code.
+  yg_min_size = align_size_up(yg_min_size, yg_align);
+  yg_max_size = align_size_up(yg_max_size, yg_align);
+  size_t yg_cur_size = align_size_up(flag_parser.young_gen_size(), yg_align);
+  yg_cur_size = MAX2(yg_cur_size, yg_min_size);
+
+  og_min_size = align_size_up(og_min_size, og_align);
+  og_max_size = align_size_up(og_max_size, og_align);
+  size_t og_cur_size = align_size_up(flag_parser.old_gen_size(), og_align);
+  og_cur_size = MAX2(og_cur_size, og_min_size);
+
+  pg_min_size = align_size_up(pg_min_size, pg_align);
+  pg_max_size = align_size_up(pg_max_size, pg_align);
+  size_t pg_cur_size = pg_min_size;
+
+  trace_gen_sizes("ps heap rnd",
+                  pg_min_size, pg_max_size,
+                  og_min_size, og_max_size,
+                  yg_min_size, yg_max_size);
+
+  // The main part of the heap (old gen + young gen) can often use a larger page
+  // size than is needed or wanted for the perm gen.  Use the "compound
+  // alignment" ReservedSpace ctor to avoid having to use the same page size for
+  // all gens.
+  ReservedSpace heap_rs(pg_max_size, pg_align, og_max_size + yg_max_size,
+                        og_align);
+  os::trace_page_sizes("ps perm", pg_min_size, pg_max_size, pg_page_sz,
+                       heap_rs.base(), pg_max_size);
+  os::trace_page_sizes("ps main", og_min_size + yg_min_size,
+                       og_max_size + yg_max_size, og_page_sz,
+                       heap_rs.base() + pg_max_size,
+                       heap_rs.size() - pg_max_size);
+  if (!heap_rs.is_reserved()) {
+    vm_shutdown_during_initialization(
+      "Could not reserve enough space for object heap");
+    return JNI_ENOMEM;
+  }
+
+  _reserved = MemRegion((HeapWord*)heap_rs.base(),
+                        (HeapWord*)(heap_rs.base() + heap_rs.size()));
+
+  CardTableExtension* const barrier_set = new CardTableExtension(_reserved, 3);
+  _barrier_set = barrier_set;
+  oopDesc::set_bs(_barrier_set);
+  if (_barrier_set == NULL) {
+    vm_shutdown_during_initialization(
+      "Could not reserve enough space for barrier set");
+    return JNI_ENOMEM;
+  }
+
+  // Initial young gen size is 4 Mb
+  //
+  // XXX - what about flag_parser.young_gen_size()?
+  const size_t init_young_size = align_size_up(4 * M, yg_align);
+  yg_cur_size = MAX2(MIN2(init_young_size, yg_max_size), yg_cur_size);
+
+  // Split the reserved space into perm gen and the main heap (everything else).
+  // The main heap uses a different alignment.
+  ReservedSpace perm_rs = heap_rs.first_part(pg_max_size);
+  ReservedSpace main_rs = heap_rs.last_part(pg_max_size, og_align);
+
+  // Make up the generations
+  // Calculate the maximum size that a generation can grow.  This
+  // includes growth into the other generation.  Note that the
+  // parameter _max_gen_size is kept as the maximum
+  // size of the generation as the boundaries currently stand.
+  // _max_gen_size is still used as that value.
+  double max_gc_pause_sec = ((double) MaxGCPauseMillis)/1000.0;
+  double max_gc_minor_pause_sec = ((double) MaxGCMinorPauseMillis)/1000.0;
+
+  _gens = new AdjoiningGenerations(main_rs,
+                                   og_cur_size,
+                                   og_min_size,
+                                   og_max_size,
+                                   yg_cur_size,
+                                   yg_min_size,
+                                   yg_max_size,
+                                   yg_align);
+
+  _old_gen = _gens->old_gen();
+  _young_gen = _gens->young_gen();
+
+  const size_t eden_capacity = _young_gen->eden_space()->capacity_in_bytes();
+  const size_t old_capacity = _old_gen->capacity_in_bytes();
+  const size_t initial_promo_size = MIN2(eden_capacity, old_capacity);
+  _size_policy =
+    new PSAdaptiveSizePolicy(eden_capacity,
+                             initial_promo_size,
+                             young_gen()->to_space()->capacity_in_bytes(),
+                             intra_generation_alignment(),
+                             max_gc_pause_sec,
+                             max_gc_minor_pause_sec,
+                             GCTimeRatio
+                             );
+
+  _perm_gen = new PSPermGen(perm_rs,
+                            pg_align,
+                            pg_cur_size,
+                            pg_cur_size,
+                            pg_max_size,
+                            "perm", 2);
+
+  assert(!UseAdaptiveGCBoundary ||
+    (old_gen()->virtual_space()->high_boundary() ==
+     young_gen()->virtual_space()->low_boundary()),
+    "Boundaries must meet");
+  // initialize the policy counters - 2 collectors, 3 generations
+  _gc_policy_counters =
+    new PSGCAdaptivePolicyCounters("ParScav:MSC", 2, 3, _size_policy);
+  _psh = this;
+
+  // Set up the GCTaskManager
+  _gc_task_manager = GCTaskManager::create(ParallelGCThreads);
+
+  if (UseParallelOldGC && !PSParallelCompact::initialize()) {
+    return JNI_ENOMEM;
+  }
+
+  return JNI_OK;
+}
+
+void ParallelScavengeHeap::post_initialize() {
+  // Need to init the tenuring threshold
+  PSScavenge::initialize();
+  if (UseParallelOldGC) {
+    PSParallelCompact::post_initialize();
+    if (VerifyParallelOldWithMarkSweep) {
+      // Will be used for verification of par old.
+      PSMarkSweep::initialize();
+    }
+  } else {
+    PSMarkSweep::initialize();
+  }
+  PSPromotionManager::initialize();
+}
+
+void ParallelScavengeHeap::update_counters() {
+  young_gen()->update_counters();
+  old_gen()->update_counters();
+  perm_gen()->update_counters();
+}
+
+size_t ParallelScavengeHeap::capacity() const {
+  size_t value = young_gen()->capacity_in_bytes() + old_gen()->capacity_in_bytes();
+  return value;
+}
+
+size_t ParallelScavengeHeap::used() const {
+  size_t value = young_gen()->used_in_bytes() + old_gen()->used_in_bytes();
+  return value;
+}
+
+bool ParallelScavengeHeap::is_maximal_no_gc() const {
+  return old_gen()->is_maximal_no_gc() && young_gen()->is_maximal_no_gc();
+}
+
+
+size_t ParallelScavengeHeap::permanent_capacity() const {
+  return perm_gen()->capacity_in_bytes();
+}
+
+size_t ParallelScavengeHeap::permanent_used() const {
+  return perm_gen()->used_in_bytes();
+}
+
+size_t ParallelScavengeHeap::max_capacity() const {
+  size_t estimated = reserved_region().byte_size();
+  estimated -= perm_gen()->reserved().byte_size();
+  if (UseAdaptiveSizePolicy) {
+    estimated -= _size_policy->max_survivor_size(young_gen()->max_size());
+  } else {
+    estimated -= young_gen()->to_space()->capacity_in_bytes();
+  }
+  return MAX2(estimated, capacity());
+}
+
+bool ParallelScavengeHeap::is_in(const void* p) const {
+  if (young_gen()->is_in(p)) {
+    return true;
+  }
+
+  if (old_gen()->is_in(p)) {
+    return true;
+  }
+
+  if (perm_gen()->is_in(p)) {
+    return true;
+  }
+
+  return false;
+}
+
+bool ParallelScavengeHeap::is_in_reserved(const void* p) const {
+  if (young_gen()->is_in_reserved(p)) {
+    return true;
+  }
+
+  if (old_gen()->is_in_reserved(p)) {
+    return true;
+  }
+
+  if (perm_gen()->is_in_reserved(p)) {
+    return true;
+  }
+
+  return false;
+}
+
+// Static method
+bool ParallelScavengeHeap::is_in_young(oop* p) {
+  ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
+  assert(heap->kind() == CollectedHeap::ParallelScavengeHeap,
+                                            "Must be ParallelScavengeHeap");
+
+  PSYoungGen* young_gen = heap->young_gen();
+
+  if (young_gen->is_in_reserved(p)) {
+    return true;
+  }
+
+  return false;
+}
+
+// Static method
+bool ParallelScavengeHeap::is_in_old_or_perm(oop* p) {
+  ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
+  assert(heap->kind() == CollectedHeap::ParallelScavengeHeap,
+                                            "Must be ParallelScavengeHeap");
+
+  PSOldGen* old_gen = heap->old_gen();
+  PSPermGen* perm_gen = heap->perm_gen();
+
+  if (old_gen->is_in_reserved(p)) {
+    return true;
+  }
+
+  if (perm_gen->is_in_reserved(p)) {
+    return true;
+  }
+
+  return false;
+}
+
+// There are two levels of allocation policy here.
+//
+// When an allocation request fails, the requesting thread must invoke a VM
+// operation, transfer control to the VM thread, and await the results of a
+// garbage collection. That is quite expensive, and we should avoid doing it
+// multiple times if possible.
+//
+// To accomplish this, we have a basic allocation policy, and also a
+// failed allocation policy.
+//
+// The basic allocation policy controls how you allocate memory without
+// attempting garbage collection. It is okay to grab locks and
+// expand the heap, if that can be done without coming to a safepoint.
+// It is likely that the basic allocation policy will not be very
+// aggressive.
+//
+// The failed allocation policy is invoked from the VM thread after
+// the basic allocation policy is unable to satisfy a mem_allocate
+// request. This policy needs to cover the entire range of collection,
+// heap expansion, and out-of-memory conditions. It should make every
+// attempt to allocate the requested memory.
+
+// Basic allocation policy. Should never be called at a safepoint, or
+// from the VM thread.
+//
+// This method must handle cases where many mem_allocate requests fail
+// simultaneously. When that happens, only one VM operation will succeed,
+// and the rest will not be executed. For that reason, this method loops
+// during failed allocation attempts. If the java heap becomes exhausted,
+// we rely on the size_policy object to force a bail out.
+HeapWord* ParallelScavengeHeap::mem_allocate(
+                                     size_t size,
+                                     bool is_noref,
+                                     bool is_tlab,
+                                     bool* gc_overhead_limit_was_exceeded) {
+  assert(!SafepointSynchronize::is_at_safepoint(), "should not be at safepoint");
+  assert(Thread::current() != (Thread*)VMThread::vm_thread(), "should not be in vm thread");
+  assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
+
+  HeapWord* result = young_gen()->allocate(size, is_tlab);
+
+  uint loop_count = 0;
+  uint gc_count = 0;
+
+  while (result == NULL) {
+    // We don't want to have multiple collections for a single filled generation.
+    // To prevent this, each thread tracks the total_collections() value, and if
+    // the count has changed, does not do a new collection.
+    //
+    // The collection count must be read only while holding the heap lock. VM
+    // operations also hold the heap lock during collections. There is a lock
+    // contention case where thread A blocks waiting on the Heap_lock, while
+    // thread B is holding it doing a collection. When thread A gets the lock,
+    // the collection count has already changed. To prevent duplicate collections,
+    // The policy MUST attempt allocations during the same period it reads the
+    // total_collections() value!
+    {
+      MutexLocker ml(Heap_lock);
+      gc_count = Universe::heap()->total_collections();
+
+      result = young_gen()->allocate(size, is_tlab);
+
+      // (1) If the requested object is too large to easily fit in the
+      //     young_gen, or
+      // (2) If GC is locked out via GCLocker, young gen is full and
+      //     the need for a GC already signalled to GCLocker (done
+      //     at a safepoint),
+      // ... then, rather than force a safepoint and (a potentially futile)
+      // collection (attempt) for each allocation, try allocation directly
+      // in old_gen. For case (2) above, we may in the future allow
+      // TLAB allocation directly in the old gen.
+      if (result != NULL) {
+        return result;
+      }
+      if (!is_tlab &&
+          size >= (young_gen()->eden_space()->capacity_in_words() / 2)) {
+        result = old_gen()->allocate(size, is_tlab);
+        if (result != NULL) {
+          return result;
+        }
+      }
+      if (GC_locker::is_active_and_needs_gc()) {
+        // GC is locked out. If this is a TLAB allocation,
+        // return NULL; the requestor will retry allocation
+        // of an idividual object at a time.
+        if (is_tlab) {
+          return NULL;
+        }
+
+        // If this thread is not in a jni critical section, we stall
+        // the requestor until the critical section has cleared and
+        // GC allowed. When the critical section clears, a GC is
+        // initiated by the last thread exiting the critical section; so
+        // we retry the allocation sequence from the beginning of the loop,
+        // rather than causing more, now probably unnecessary, GC attempts.
+        JavaThread* jthr = JavaThread::current();
+        if (!jthr->in_critical()) {
+          MutexUnlocker mul(Heap_lock);
+          GC_locker::stall_until_clear();
+          continue;
+        } else {
+          if (CheckJNICalls) {
+            fatal("Possible deadlock due to allocating while"
+                  " in jni critical section");
+          }
+          return NULL;
+        }
+      }
+    }
+
+    if (result == NULL) {
+
+      // Exit the loop if if the gc time limit has been exceeded.
+      // The allocation must have failed above (result must be NULL),
+      // and the most recent collection must have exceeded the
+      // gc time limit.  Exit the loop so that an out-of-memory
+      // will be thrown (returning a NULL will do that), but
+      // clear gc_time_limit_exceeded so that the next collection
+      // will succeeded if the applications decides to handle the
+      // out-of-memory and tries to go on.
+      *gc_overhead_limit_was_exceeded = size_policy()->gc_time_limit_exceeded();
+      if (size_policy()->gc_time_limit_exceeded()) {
+        size_policy()->set_gc_time_limit_exceeded(false);
+        if (PrintGCDetails && Verbose) {
+        gclog_or_tty->print_cr("ParallelScavengeHeap::mem_allocate: "
+          "return NULL because gc_time_limit_exceeded is set");
+        }
+        return NULL;
+      }
+
+      // Generate a VM operation
+      VM_ParallelGCFailedAllocation op(size, is_tlab, gc_count);
+      VMThread::execute(&op);
+
+      // Did the VM operation execute? If so, return the result directly.
+      // This prevents us from looping until time out on requests that can
+      // not be satisfied.
+      if (op.prologue_succeeded()) {
+        assert(Universe::heap()->is_in_or_null(op.result()),
+          "result not in heap");
+
+        // If GC was locked out during VM operation then retry allocation
+        // and/or stall as necessary.
+        if (op.gc_locked()) {
+          assert(op.result() == NULL, "must be NULL if gc_locked() is true");
+          continue;  // retry and/or stall as necessary
+        }
+        // If a NULL result is being returned, an out-of-memory
+        // will be thrown now.  Clear the gc_time_limit_exceeded
+        // flag to avoid the following situation.
+        //      gc_time_limit_exceeded is set during a collection
+        //      the collection fails to return enough space and an OOM is thrown
+        //      the next GC is skipped because the gc_time_limit_exceeded
+        //        flag is set and another OOM is thrown
+        if (op.result() == NULL) {
+          size_policy()->set_gc_time_limit_exceeded(false);
+        }
+        return op.result();
+      }
+    }
+
+    // The policy object will prevent us from looping forever. If the
+    // time spent in gc crosses a threshold, we will bail out.
+    loop_count++;
+    if ((result == NULL) && (QueuedAllocationWarningCount > 0) &&
+        (loop_count % QueuedAllocationWarningCount == 0)) {
+      warning("ParallelScavengeHeap::mem_allocate retries %d times \n\t"
+              " size=%d %s", loop_count, size, is_tlab ? "(TLAB)" : "");
+    }
+  }
+
+  return result;
+}
+
+// Failed allocation policy. Must be called from the VM thread, and
+// only at a safepoint! Note that this method has policy for allocation
+// flow, and NOT collection policy. So we do not check for gc collection
+// time over limit here, that is the responsibility of the heap specific
+// collection methods. This method decides where to attempt allocations,
+// and when to attempt collections, but no collection specific policy.
+HeapWord* ParallelScavengeHeap::failed_mem_allocate(size_t size, bool is_tlab) {
+  assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
+  assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
+  assert(!Universe::heap()->is_gc_active(), "not reentrant");
+  assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
+
+  size_t mark_sweep_invocation_count = total_invocations();
+
+  // We assume (and assert!) that an allocation at this point will fail
+  // unless we collect.
+
+  // First level allocation failure, scavenge and allocate in young gen.
+  GCCauseSetter gccs(this, GCCause::_allocation_failure);
+  PSScavenge::invoke();
+  HeapWord* result = young_gen()->allocate(size, is_tlab);
+
+  // Second level allocation failure.
+  //   Mark sweep and allocate in young generation.
+  if (result == NULL) {
+    // There is some chance the scavenge method decided to invoke mark_sweep.
+    // Don't mark sweep twice if so.
+    if (mark_sweep_invocation_count == total_invocations()) {
+      invoke_full_gc(false);
+      result = young_gen()->allocate(size, is_tlab);
+    }
+  }
+
+  // Third level allocation failure.
+  //   After mark sweep and young generation allocation failure,
+  //   allocate in old generation.
+  if (result == NULL && !is_tlab) {
+    result = old_gen()->allocate(size, is_tlab);
+  }
+
+  // Fourth level allocation failure. We're running out of memory.
+  //   More complete mark sweep and allocate in young generation.
+  if (result == NULL) {
+    invoke_full_gc(true);
+    result = young_gen()->allocate(size, is_tlab);
+  }
+
+  // Fifth level allocation failure.
+  //   After more complete mark sweep, allocate in old generation.
+  if (result == NULL && !is_tlab) {
+    result = old_gen()->allocate(size, is_tlab);
+  }
+
+  return result;
+}
+
+//
+// This is the policy loop for allocating in the permanent generation.
+// If the initial allocation fails, we create a vm operation which will
+// cause a collection.
+HeapWord* ParallelScavengeHeap::permanent_mem_allocate(size_t size) {
+  assert(!SafepointSynchronize::is_at_safepoint(), "should not be at safepoint");
+  assert(Thread::current() != (Thread*)VMThread::vm_thread(), "should not be in vm thread");
+  assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
+
+  HeapWord* result;
+
+  uint loop_count = 0;
+  uint gc_count = 0;
+  uint full_gc_count = 0;
+
+  do {
+    // We don't want to have multiple collections for a single filled generation.
+    // To prevent this, each thread tracks the total_collections() value, and if
+    // the count has changed, does not do a new collection.
+    //
+    // The collection count must be read only while holding the heap lock. VM
+    // operations also hold the heap lock during collections. There is a lock
+    // contention case where thread A blocks waiting on the Heap_lock, while
+    // thread B is holding it doing a collection. When thread A gets the lock,
+    // the collection count has already changed. To prevent duplicate collections,
+    // The policy MUST attempt allocations during the same period it reads the
+    // total_collections() value!
+    {
+      MutexLocker ml(Heap_lock);
+      gc_count      = Universe::heap()->total_collections();
+      full_gc_count = Universe::heap()->total_full_collections();
+
+      result = perm_gen()->allocate_permanent(size);
+    }
+
+    if (result == NULL) {
+
+      // Exit the loop if the gc time limit has been exceeded.
+      // The allocation must have failed above (result must be NULL),
+      // and the most recent collection must have exceeded the
+      // gc time limit.  Exit the loop so that an out-of-memory
+      // will be thrown (returning a NULL will do that), but
+      // clear gc_time_limit_exceeded so that the next collection
+      // will succeeded if the applications decides to handle the
+      // out-of-memory and tries to go on.
+      if (size_policy()->gc_time_limit_exceeded()) {
+        size_policy()->set_gc_time_limit_exceeded(false);
+        if (PrintGCDetails && Verbose) {
+        gclog_or_tty->print_cr("ParallelScavengeHeap::permanent_mem_allocate: "
+          "return NULL because gc_time_limit_exceeded is set");
+        }
+        assert(result == NULL, "Allocation did not fail");
+        return NULL;
+      }
+
+      // Generate a VM operation
+      VM_ParallelGCFailedPermanentAllocation op(size, gc_count, full_gc_count);
+      VMThread::execute(&op);
+
+      // Did the VM operation execute? If so, return the result directly.
+      // This prevents us from looping until time out on requests that can
+      // not be satisfied.
+      if (op.prologue_succeeded()) {
+        assert(Universe::heap()->is_in_permanent_or_null(op.result()),
+          "result not in heap");
+        // If a NULL results is being returned, an out-of-memory
+        // will be thrown now.  Clear the gc_time_limit_exceeded
+        // flag to avoid the following situation.
+        //      gc_time_limit_exceeded is set during a collection
+        //      the collection fails to return enough space and an OOM is thrown
+        //      the next GC is skipped because the gc_time_limit_exceeded
+        //        flag is set and another OOM is thrown
+        if (op.result() == NULL) {
+          size_policy()->set_gc_time_limit_exceeded(false);
+        }
+        return op.result();
+      }
+    }
+
+    // The policy object will prevent us from looping forever. If the
+    // time spent in gc crosses a threshold, we will bail out.
+    loop_count++;
+    if ((QueuedAllocationWarningCount > 0) &&
+        (loop_count % QueuedAllocationWarningCount == 0)) {
+      warning("ParallelScavengeHeap::permanent_mem_allocate retries %d times \n\t"
+              " size=%d", loop_count, size);
+    }
+  } while (result == NULL);
+
+  return result;
+}
+
+//
+// This is the policy code for permanent allocations which have failed
+// and require a collection. Note that just as in failed_mem_allocate,
+// we do not set collection policy, only where & when to allocate and
+// collect.
+HeapWord* ParallelScavengeHeap::failed_permanent_mem_allocate(size_t size) {
+  assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
+  assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
+  assert(!Universe::heap()->is_gc_active(), "not reentrant");
+  assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
+  assert(size > perm_gen()->free_in_words(), "Allocation should fail");
+
+  // We assume (and assert!) that an allocation at this point will fail
+  // unless we collect.
+
+  // First level allocation failure.  Mark-sweep and allocate in perm gen.
+  GCCauseSetter gccs(this, GCCause::_allocation_failure);
+  invoke_full_gc(false);
+  HeapWord* result = perm_gen()->allocate_permanent(size);
+
+  // Second level allocation failure. We're running out of memory.
+  if (result == NULL) {
+    invoke_full_gc(true);
+    result = perm_gen()->allocate_permanent(size);
+  }
+
+  return result;
+}
+
+void ParallelScavengeHeap::ensure_parsability(bool retire_tlabs) {
+  CollectedHeap::ensure_parsability(retire_tlabs);
+  young_gen()->eden_space()->ensure_parsability();
+}
+
+size_t ParallelScavengeHeap::unsafe_max_alloc() {
+  return young_gen()->eden_space()->free_in_bytes();
+}
+
+size_t ParallelScavengeHeap::tlab_capacity(Thread* thr) const {
+  return young_gen()->eden_space()->tlab_capacity(thr);
+}
+
+size_t ParallelScavengeHeap::unsafe_max_tlab_alloc(Thread* thr) const {
+  return young_gen()->eden_space()->unsafe_max_tlab_alloc(thr);
+}
+
+HeapWord* ParallelScavengeHeap::allocate_new_tlab(size_t size) {
+  return young_gen()->allocate(size, true);
+}
+
+void ParallelScavengeHeap::fill_all_tlabs(bool retire) {
+  CollectedHeap::fill_all_tlabs(retire);
+}
+
+void ParallelScavengeHeap::accumulate_statistics_all_tlabs() {
+  CollectedHeap::accumulate_statistics_all_tlabs();
+}
+
+void ParallelScavengeHeap::resize_all_tlabs() {
+  CollectedHeap::resize_all_tlabs();
+}
+
+// This method is used by System.gc() and JVMTI.
+void ParallelScavengeHeap::collect(GCCause::Cause cause) {
+  assert(!Heap_lock->owned_by_self(),
+    "this thread should not own the Heap_lock");
+
+  unsigned int gc_count      = 0;
+  unsigned int full_gc_count = 0;
+  {
+    MutexLocker ml(Heap_lock);
+    // This value is guarded by the Heap_lock
+    gc_count      = Universe::heap()->total_collections();
+    full_gc_count = Universe::heap()->total_full_collections();
+  }
+
+  VM_ParallelGCSystemGC op(gc_count, full_gc_count, cause);
+  VMThread::execute(&op);
+}
+
+// This interface assumes that it's being called by the
+// vm thread. It collects the heap assuming that the
+// heap lock is already held and that we are executing in
+// the context of the vm thread.
+void ParallelScavengeHeap::collect_as_vm_thread(GCCause::Cause cause) {
+  assert(Thread::current()->is_VM_thread(), "Precondition#1");
+  assert(Heap_lock->is_locked(), "Precondition#2");
+  GCCauseSetter gcs(this, cause);
+  switch (cause) {
+    case GCCause::_heap_inspection:
+    case GCCause::_heap_dump: {
+      HandleMark hm;
+      invoke_full_gc(false);
+      break;
+    }
+    default: // XXX FIX ME
+      ShouldNotReachHere();
+  }
+}
+
+
+void ParallelScavengeHeap::oop_iterate(OopClosure* cl) {
+  Unimplemented();
+}
+
+void ParallelScavengeHeap::object_iterate(ObjectClosure* cl) {
+  young_gen()->object_iterate(cl);
+  old_gen()->object_iterate(cl);
+  perm_gen()->object_iterate(cl);
+}
+
+void ParallelScavengeHeap::permanent_oop_iterate(OopClosure* cl) {
+  Unimplemented();
+}
+
+void ParallelScavengeHeap::permanent_object_iterate(ObjectClosure* cl) {
+  perm_gen()->object_iterate(cl);
+}
+
+HeapWord* ParallelScavengeHeap::block_start(const void* addr) const {
+  if (young_gen()->is_in_reserved(addr)) {
+    assert(young_gen()->is_in(addr),
+           "addr should be in allocated part of young gen");
+    Unimplemented();
+  } else if (old_gen()->is_in_reserved(addr)) {
+    assert(old_gen()->is_in(addr),
+           "addr should be in allocated part of old gen");
+    return old_gen()->start_array()->object_start((HeapWord*)addr);
+  } else if (perm_gen()->is_in_reserved(addr)) {
+    assert(perm_gen()->is_in(addr),
+           "addr should be in allocated part of perm gen");
+    return perm_gen()->start_array()->object_start((HeapWord*)addr);
+  }
+  return 0;
+}
+
+size_t ParallelScavengeHeap::block_size(const HeapWord* addr) const {
+  return oop(addr)->size();
+}
+
+bool ParallelScavengeHeap::block_is_obj(const HeapWord* addr) const {
+  return block_start(addr) == addr;
+}
+
+jlong ParallelScavengeHeap::millis_since_last_gc() {
+  return UseParallelOldGC ?
+    PSParallelCompact::millis_since_last_gc() :
+    PSMarkSweep::millis_since_last_gc();
+}
+
+void ParallelScavengeHeap::prepare_for_verify() {
+  ensure_parsability(false);  // no need to retire TLABs for verification
+}
+
+void ParallelScavengeHeap::print() const { print_on(tty); }
+
+void ParallelScavengeHeap::print_on(outputStream* st) const {
+  young_gen()->print_on(st);
+  old_gen()->print_on(st);
+  perm_gen()->print_on(st);
+}
+
+void ParallelScavengeHeap::gc_threads_do(ThreadClosure* tc) const {
+  PSScavenge::gc_task_manager()->threads_do(tc);
+}
+
+void ParallelScavengeHeap::print_gc_threads_on(outputStream* st) const {
+  PSScavenge::gc_task_manager()->print_threads_on(st);
+}
+
+void ParallelScavengeHeap::print_tracing_info() const {
+  if (TraceGen0Time) {
+    double time = PSScavenge::accumulated_time()->seconds();
+    tty->print_cr("[Accumulated GC generation 0 time %3.7f secs]", time);
+  }
+  if (TraceGen1Time) {
+    double time = PSMarkSweep::accumulated_time()->seconds();
+    tty->print_cr("[Accumulated GC generation 1 time %3.7f secs]", time);
+  }
+}
+
+
+void ParallelScavengeHeap::verify(bool allow_dirty, bool silent) {
+  // Why do we need the total_collections()-filter below?
+  if (total_collections() > 0) {
+    if (!silent) {
+      gclog_or_tty->print("permanent ");
+    }
+    perm_gen()->verify(allow_dirty);
+
+    if (!silent) {
+      gclog_or_tty->print("tenured ");
+    }
+    old_gen()->verify(allow_dirty);
+
+    if (!silent) {
+      gclog_or_tty->print("eden ");
+    }
+    young_gen()->verify(allow_dirty);
+  }
+  if (!silent) {
+    gclog_or_tty->print("ref_proc ");
+  }
+  ReferenceProcessor::verify();
+}
+
+void ParallelScavengeHeap::print_heap_change(size_t prev_used) {
+  if (PrintGCDetails && Verbose) {
+    gclog_or_tty->print(" "  SIZE_FORMAT
+                        "->" SIZE_FORMAT
+                        "("  SIZE_FORMAT ")",
+                        prev_used, used(), capacity());
+  } else {
+    gclog_or_tty->print(" "  SIZE_FORMAT "K"
+                        "->" SIZE_FORMAT "K"
+                        "("  SIZE_FORMAT "K)",
+                        prev_used / K, used() / K, capacity() / K);
+  }
+}
+
+ParallelScavengeHeap* ParallelScavengeHeap::heap() {
+  assert(_psh != NULL, "Uninitialized access to ParallelScavengeHeap::heap()");
+  assert(_psh->kind() == CollectedHeap::ParallelScavengeHeap, "not a parallel scavenge heap");
+  return _psh;
+}
+
+// Before delegating the resize to the young generation,
+// the reserved space for the young and old generations
+// may be changed to accomodate the desired resize.
+void ParallelScavengeHeap::resize_young_gen(size_t eden_size,
+    size_t survivor_size) {
+  if (UseAdaptiveGCBoundary) {
+    if (size_policy()->bytes_absorbed_from_eden() != 0) {
+      size_policy()->reset_bytes_absorbed_from_eden();
+      return;  // The generation changed size already.
+    }
+    gens()->adjust_boundary_for_young_gen_needs(eden_size, survivor_size);
+  }
+
+  // Delegate the resize to the generation.
+  _young_gen->resize(eden_size, survivor_size);
+}
+
+// Before delegating the resize to the old generation,
+// the reserved space for the young and old generations
+// may be changed to accomodate the desired resize.
+void ParallelScavengeHeap::resize_old_gen(size_t desired_free_space) {
+  if (UseAdaptiveGCBoundary) {
+    if (size_policy()->bytes_absorbed_from_eden() != 0) {
+      size_policy()->reset_bytes_absorbed_from_eden();
+      return;  // The generation changed size already.
+    }
+    gens()->adjust_boundary_for_old_gen_needs(desired_free_space);
+  }
+
+  // Delegate the resize to the generation.
+  _old_gen->resize(desired_free_space);
+}