--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/parallel/psPromotionManager.cpp	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,514 @@
+/*
+ * Copyright (c) 2002, 2017, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "gc/parallel/gcTaskManager.hpp"
+#include "gc/parallel/mutableSpace.hpp"
+#include "gc/parallel/parallelScavengeHeap.hpp"
+#include "gc/parallel/psOldGen.hpp"
+#include "gc/parallel/psPromotionManager.inline.hpp"
+#include "gc/parallel/psScavenge.inline.hpp"
+#include "gc/shared/gcTrace.hpp"
+#include "gc/shared/preservedMarks.inline.hpp"
+#include "gc/shared/taskqueue.inline.hpp"
+#include "logging/log.hpp"
+#include "logging/logStream.hpp"
+#include "memory/allocation.inline.hpp"
+#include "memory/memRegion.hpp"
+#include "memory/padded.inline.hpp"
+#include "memory/resourceArea.hpp"
+#include "oops/instanceKlass.inline.hpp"
+#include "oops/instanceMirrorKlass.inline.hpp"
+#include "oops/objArrayKlass.inline.hpp"
+#include "oops/oop.inline.hpp"
+
+PaddedEnd<PSPromotionManager>* PSPromotionManager::_manager_array = NULL;
+OopStarTaskQueueSet*           PSPromotionManager::_stack_array_depth = NULL;
+PreservedMarksSet*             PSPromotionManager::_preserved_marks_set = NULL;
+PSOldGen*                      PSPromotionManager::_old_gen = NULL;
+MutableSpace*                  PSPromotionManager::_young_space = NULL;
+
+void PSPromotionManager::initialize() {
+  ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
+
+  _old_gen = heap->old_gen();
+  _young_space = heap->young_gen()->to_space();
+
+  const uint promotion_manager_num = ParallelGCThreads + 1;
+
+  // To prevent false sharing, we pad the PSPromotionManagers
+  // and make sure that the first instance starts at a cache line.
+  assert(_manager_array == NULL, "Attempt to initialize twice");
+  _manager_array = PaddedArray<PSPromotionManager, mtGC>::create_unfreeable(promotion_manager_num);
+  guarantee(_manager_array != NULL, "Could not initialize promotion manager");
+
+  _stack_array_depth = new OopStarTaskQueueSet(ParallelGCThreads);
+  guarantee(_stack_array_depth != NULL, "Could not initialize promotion manager");
+
+  // Create and register the PSPromotionManager(s) for the worker threads.
+  for(uint i=0; i<ParallelGCThreads; i++) {
+    stack_array_depth()->register_queue(i, _manager_array[i].claimed_stack_depth());
+  }
+  // The VMThread gets its own PSPromotionManager, which is not available
+  // for work stealing.
+
+  assert(_preserved_marks_set == NULL, "Attempt to initialize twice");
+  _preserved_marks_set = new PreservedMarksSet(true /* in_c_heap */);
+  guarantee(_preserved_marks_set != NULL, "Could not initialize preserved marks set");
+  _preserved_marks_set->init(promotion_manager_num);
+  for (uint i = 0; i < promotion_manager_num; i += 1) {
+    _manager_array[i].register_preserved_marks(_preserved_marks_set->get(i));
+  }
+}
+
+// Helper functions to get around the circular dependency between
+// psScavenge.inline.hpp and psPromotionManager.inline.hpp.
+bool PSPromotionManager::should_scavenge(oop* p, bool check_to_space) {
+  return PSScavenge::should_scavenge(p, check_to_space);
+}
+bool PSPromotionManager::should_scavenge(narrowOop* p, bool check_to_space) {
+  return PSScavenge::should_scavenge(p, check_to_space);
+}
+
+PSPromotionManager* PSPromotionManager::gc_thread_promotion_manager(uint index) {
+  assert(index < ParallelGCThreads, "index out of range");
+  assert(_manager_array != NULL, "Sanity");
+  return &_manager_array[index];
+}
+
+PSPromotionManager* PSPromotionManager::vm_thread_promotion_manager() {
+  assert(_manager_array != NULL, "Sanity");
+  return &_manager_array[ParallelGCThreads];
+}
+
+void PSPromotionManager::pre_scavenge() {
+  ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
+
+  _preserved_marks_set->assert_empty();
+  _young_space = heap->young_gen()->to_space();
+
+  for(uint i=0; i<ParallelGCThreads+1; i++) {
+    manager_array(i)->reset();
+  }
+}
+
+bool PSPromotionManager::post_scavenge(YoungGCTracer& gc_tracer) {
+  bool promotion_failure_occurred = false;
+
+  TASKQUEUE_STATS_ONLY(print_taskqueue_stats());
+  for (uint i = 0; i < ParallelGCThreads + 1; i++) {
+    PSPromotionManager* manager = manager_array(i);
+    assert(manager->claimed_stack_depth()->is_empty(), "should be empty");
+    if (manager->_promotion_failed_info.has_failed()) {
+      gc_tracer.report_promotion_failed(manager->_promotion_failed_info);
+      promotion_failure_occurred = true;
+    }
+    manager->flush_labs();
+  }
+  if (!promotion_failure_occurred) {
+    // If there was no promotion failure, the preserved mark stacks
+    // should be empty.
+    _preserved_marks_set->assert_empty();
+  }
+  return promotion_failure_occurred;
+}
+
+#if TASKQUEUE_STATS
+void
+PSPromotionManager::print_local_stats(outputStream* const out, uint i) const {
+  #define FMT " " SIZE_FORMAT_W(10)
+  out->print_cr("%3u" FMT FMT FMT FMT, i, _masked_pushes, _masked_steals,
+                _arrays_chunked, _array_chunks_processed);
+  #undef FMT
+}
+
+static const char* const pm_stats_hdr[] = {
+  "    --------masked-------     arrays      array",
+  "thr       push      steal    chunked     chunks",
+  "--- ---------- ---------- ---------- ----------"
+};
+
+void
+PSPromotionManager::print_taskqueue_stats() {
+  if (!log_develop_is_enabled(Trace, gc, task, stats)) {
+    return;
+  }
+  Log(gc, task, stats) log;
+  ResourceMark rm;
+  LogStream ls(log.trace());
+  outputStream* out = &ls;
+  out->print_cr("== GC Tasks Stats, GC %3d",
+                ParallelScavengeHeap::heap()->total_collections());
+
+  TaskQueueStats totals;
+  out->print("thr "); TaskQueueStats::print_header(1, out); out->cr();
+  out->print("--- "); TaskQueueStats::print_header(2, out); out->cr();
+  for (uint i = 0; i < ParallelGCThreads + 1; ++i) {
+    TaskQueueStats& next = manager_array(i)->_claimed_stack_depth.stats;
+    out->print("%3d ", i); next.print(out); out->cr();
+    totals += next;
+  }
+  out->print("tot "); totals.print(out); out->cr();
+
+  const uint hlines = sizeof(pm_stats_hdr) / sizeof(pm_stats_hdr[0]);
+  for (uint i = 0; i < hlines; ++i) out->print_cr("%s", pm_stats_hdr[i]);
+  for (uint i = 0; i < ParallelGCThreads + 1; ++i) {
+    manager_array(i)->print_local_stats(out, i);
+  }
+}
+
+void
+PSPromotionManager::reset_stats() {
+  claimed_stack_depth()->stats.reset();
+  _masked_pushes = _masked_steals = 0;
+  _arrays_chunked = _array_chunks_processed = 0;
+}
+#endif // TASKQUEUE_STATS
+
+PSPromotionManager::PSPromotionManager() {
+  ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
+
+  // We set the old lab's start array.
+  _old_lab.set_start_array(old_gen()->start_array());
+
+  uint queue_size;
+  claimed_stack_depth()->initialize();
+  queue_size = claimed_stack_depth()->max_elems();
+
+  _totally_drain = (ParallelGCThreads == 1) || (GCDrainStackTargetSize == 0);
+  if (_totally_drain) {
+    _target_stack_size = 0;
+  } else {
+    // don't let the target stack size to be more than 1/4 of the entries
+    _target_stack_size = (uint) MIN2((uint) GCDrainStackTargetSize,
+                                     (uint) (queue_size / 4));
+  }
+
+  _array_chunk_size = ParGCArrayScanChunk;
+  // let's choose 1.5x the chunk size
+  _min_array_size_for_chunking = 3 * _array_chunk_size / 2;
+
+  _preserved_marks = NULL;
+
+  reset();
+}
+
+void PSPromotionManager::reset() {
+  assert(stacks_empty(), "reset of non-empty stack");
+
+  // We need to get an assert in here to make sure the labs are always flushed.
+
+  ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
+
+  // Do not prefill the LAB's, save heap wastage!
+  HeapWord* lab_base = young_space()->top();
+  _young_lab.initialize(MemRegion(lab_base, (size_t)0));
+  _young_gen_is_full = false;
+
+  lab_base = old_gen()->object_space()->top();
+  _old_lab.initialize(MemRegion(lab_base, (size_t)0));
+  _old_gen_is_full = false;
+
+  _promotion_failed_info.reset();
+
+  TASKQUEUE_STATS_ONLY(reset_stats());
+}
+
+void PSPromotionManager::register_preserved_marks(PreservedMarks* preserved_marks) {
+  assert(_preserved_marks == NULL, "do not set it twice");
+  _preserved_marks = preserved_marks;
+}
+
+class ParRestoreGCTask : public GCTask {
+private:
+  const uint _id;
+  PreservedMarksSet* const _preserved_marks_set;
+  volatile size_t* const _total_size_addr;
+
+public:
+  virtual char* name() {
+    return (char*) "preserved mark restoration task";
+  }
+
+  virtual void do_it(GCTaskManager* manager, uint which){
+    _preserved_marks_set->get(_id)->restore_and_increment(_total_size_addr);
+  }
+
+  ParRestoreGCTask(uint id,
+                   PreservedMarksSet* preserved_marks_set,
+                   volatile size_t* total_size_addr)
+    : _id(id),
+      _preserved_marks_set(preserved_marks_set),
+      _total_size_addr(total_size_addr) { }
+};
+
+class PSRestorePreservedMarksTaskExecutor : public RestorePreservedMarksTaskExecutor {
+private:
+  GCTaskManager* _gc_task_manager;
+
+public:
+  PSRestorePreservedMarksTaskExecutor(GCTaskManager* gc_task_manager)
+      : _gc_task_manager(gc_task_manager) { }
+
+  void restore(PreservedMarksSet* preserved_marks_set,
+               volatile size_t* total_size_addr) {
+    // GCTask / GCTaskQueue are ResourceObjs
+    ResourceMark rm;
+
+    GCTaskQueue* q = GCTaskQueue::create();
+    for (uint i = 0; i < preserved_marks_set->num(); i += 1) {
+      q->enqueue(new ParRestoreGCTask(i, preserved_marks_set, total_size_addr));
+    }
+    _gc_task_manager->execute_and_wait(q);
+  }
+};
+
+void PSPromotionManager::restore_preserved_marks() {
+  PSRestorePreservedMarksTaskExecutor task_executor(PSScavenge::gc_task_manager());
+  _preserved_marks_set->restore(&task_executor);
+}
+
+void PSPromotionManager::drain_stacks_depth(bool totally_drain) {
+  totally_drain = totally_drain || _totally_drain;
+
+#ifdef ASSERT
+  ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
+  MutableSpace* to_space = heap->young_gen()->to_space();
+  MutableSpace* old_space = heap->old_gen()->object_space();
+#endif /* ASSERT */
+
+  OopStarTaskQueue* const tq = claimed_stack_depth();
+  do {
+    StarTask p;
+
+    // Drain overflow stack first, so other threads can steal from
+    // claimed stack while we work.
+    while (tq->pop_overflow(p)) {
+      process_popped_location_depth(p);
+    }
+
+    if (totally_drain) {
+      while (tq->pop_local(p)) {
+        process_popped_location_depth(p);
+      }
+    } else {
+      while (tq->size() > _target_stack_size && tq->pop_local(p)) {
+        process_popped_location_depth(p);
+      }
+    }
+  } while ((totally_drain && !tq->taskqueue_empty()) || !tq->overflow_empty());
+
+  assert(!totally_drain || tq->taskqueue_empty(), "Sanity");
+  assert(totally_drain || tq->size() <= _target_stack_size, "Sanity");
+  assert(tq->overflow_empty(), "Sanity");
+}
+
+void PSPromotionManager::flush_labs() {
+  assert(stacks_empty(), "Attempt to flush lab with live stack");
+
+  // If either promotion lab fills up, we can flush the
+  // lab but not refill it, so check first.
+  assert(!_young_lab.is_flushed() || _young_gen_is_full, "Sanity");
+  if (!_young_lab.is_flushed())
+    _young_lab.flush();
+
+  assert(!_old_lab.is_flushed() || _old_gen_is_full, "Sanity");
+  if (!_old_lab.is_flushed())
+    _old_lab.flush();
+
+  // Let PSScavenge know if we overflowed
+  if (_young_gen_is_full) {
+    PSScavenge::set_survivor_overflow(true);
+  }
+}
+
+template <class T> void PSPromotionManager::process_array_chunk_work(
+                                                 oop obj,
+                                                 int start, int end) {
+  assert(start <= end, "invariant");
+  T* const base      = (T*)objArrayOop(obj)->base();
+  T* p               = base + start;
+  T* const chunk_end = base + end;
+  while (p < chunk_end) {
+    if (PSScavenge::should_scavenge(p)) {
+      claim_or_forward_depth(p);
+    }
+    ++p;
+  }
+}
+
+void PSPromotionManager::process_array_chunk(oop old) {
+  assert(PSChunkLargeArrays, "invariant");
+  assert(old->is_objArray(), "invariant");
+  assert(old->is_forwarded(), "invariant");
+
+  TASKQUEUE_STATS_ONLY(++_array_chunks_processed);
+
+  oop const obj = old->forwardee();
+
+  int start;
+  int const end = arrayOop(old)->length();
+  if (end > (int) _min_array_size_for_chunking) {
+    // we'll chunk more
+    start = end - _array_chunk_size;
+    assert(start > 0, "invariant");
+    arrayOop(old)->set_length(start);
+    push_depth(mask_chunked_array_oop(old));
+    TASKQUEUE_STATS_ONLY(++_masked_pushes);
+  } else {
+    // this is the final chunk for this array
+    start = 0;
+    int const actual_length = arrayOop(obj)->length();
+    arrayOop(old)->set_length(actual_length);
+  }
+
+  if (UseCompressedOops) {
+    process_array_chunk_work<narrowOop>(obj, start, end);
+  } else {
+    process_array_chunk_work<oop>(obj, start, end);
+  }
+}
+
+class PushContentsClosure : public ExtendedOopClosure {
+  PSPromotionManager* _pm;
+ public:
+  PushContentsClosure(PSPromotionManager* pm) : _pm(pm) {}
+
+  template <typename T> void do_oop_nv(T* p) {
+    if (PSScavenge::should_scavenge(p)) {
+      _pm->claim_or_forward_depth(p);
+    }
+  }
+
+  virtual void do_oop(oop* p)       { do_oop_nv(p); }
+  virtual void do_oop(narrowOop* p) { do_oop_nv(p); }
+
+  // Don't use the oop verification code in the oop_oop_iterate framework.
+  debug_only(virtual bool should_verify_oops() { return false; })
+};
+
+void InstanceKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) {
+  PushContentsClosure cl(pm);
+  oop_oop_iterate_oop_maps_reverse<true>(obj, &cl);
+}
+
+void InstanceMirrorKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) {
+    // Note that we don't have to follow the mirror -> klass pointer, since all
+    // klasses that are dirty will be scavenged when we iterate over the
+    // ClassLoaderData objects.
+
+  InstanceKlass::oop_ps_push_contents(obj, pm);
+
+  PushContentsClosure cl(pm);
+  oop_oop_iterate_statics<true>(obj, &cl);
+}
+
+void InstanceClassLoaderKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) {
+  InstanceKlass::oop_ps_push_contents(obj, pm);
+
+  // This is called by the young collector. It will already have taken care of
+  // all class loader data. So, we don't have to follow the class loader ->
+  // class loader data link.
+}
+
+template <class T>
+static void oop_ps_push_contents_specialized(oop obj, InstanceRefKlass *klass, PSPromotionManager* pm) {
+  T* referent_addr = (T*)java_lang_ref_Reference::referent_addr(obj);
+  if (PSScavenge::should_scavenge(referent_addr)) {
+    ReferenceProcessor* rp = PSScavenge::reference_processor();
+    if (rp->discover_reference(obj, klass->reference_type())) {
+      // reference already enqueued, referent and next will be traversed later
+      klass->InstanceKlass::oop_ps_push_contents(obj, pm);
+      return;
+    } else {
+      // treat referent as normal oop
+      pm->claim_or_forward_depth(referent_addr);
+    }
+  }
+  // Treat discovered as normal oop, if ref is not "active",
+  // i.e. if next is non-NULL.
+  T* next_addr = (T*)java_lang_ref_Reference::next_addr(obj);
+  T  next_oop = oopDesc::load_heap_oop(next_addr);
+  if (!oopDesc::is_null(next_oop)) { // i.e. ref is not "active"
+    T* discovered_addr = (T*)java_lang_ref_Reference::discovered_addr(obj);
+    log_develop_trace(gc, ref)("   Process discovered as normal " PTR_FORMAT, p2i(discovered_addr));
+    if (PSScavenge::should_scavenge(discovered_addr)) {
+      pm->claim_or_forward_depth(discovered_addr);
+    }
+  }
+  // Treat next as normal oop;  next is a link in the reference queue.
+  if (PSScavenge::should_scavenge(next_addr)) {
+    pm->claim_or_forward_depth(next_addr);
+  }
+  klass->InstanceKlass::oop_ps_push_contents(obj, pm);
+}
+
+void InstanceRefKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) {
+  if (UseCompressedOops) {
+    oop_ps_push_contents_specialized<narrowOop>(obj, this, pm);
+  } else {
+    oop_ps_push_contents_specialized<oop>(obj, this, pm);
+  }
+}
+
+void ObjArrayKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) {
+  assert(obj->is_objArray(), "obj must be obj array");
+  PushContentsClosure cl(pm);
+  oop_oop_iterate_elements<true>(objArrayOop(obj), &cl);
+}
+
+void TypeArrayKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) {
+  assert(obj->is_typeArray(),"must be a type array");
+  ShouldNotReachHere();
+}
+
+oop PSPromotionManager::oop_promotion_failed(oop obj, markOop obj_mark) {
+  assert(_old_gen_is_full || PromotionFailureALot, "Sanity");
+
+  // Attempt to CAS in the header.
+  // This tests if the header is still the same as when
+  // this started.  If it is the same (i.e., no forwarding
+  // pointer has been installed), then this thread owns
+  // it.
+  if (obj->cas_forward_to(obj, obj_mark)) {
+    // We won any races, we "own" this object.
+    assert(obj == obj->forwardee(), "Sanity");
+
+    _promotion_failed_info.register_copy_failure(obj->size());
+
+    push_contents(obj);
+
+    _preserved_marks->push_if_necessary(obj, obj_mark);
+  }  else {
+    // We lost, someone else "owns" this object
+    guarantee(obj->is_forwarded(), "Object must be forwarded if the cas failed.");
+
+    // No unallocation to worry about.
+    obj = obj->forwardee();
+  }
+
+  log_develop_trace(gc, scavenge)("{promotion-failure %s " PTR_FORMAT " (%d)}", obj->klass()->internal_name(), p2i(obj), obj->size());
+
+  return obj;
+}