--- /dev/null	2018-04-03 12:55:20.301839954 +0200
+++ new/src/hotspot/share/gc/z/zMark.cpp	2018-06-06 00:41:58.663909629 +0200
@@ -0,0 +1,684 @@
+/*
+ * Copyright (c) 2015, 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 "gc/z/zBarrier.inline.hpp"
+#include "gc/z/zMark.inline.hpp"
+#include "gc/z/zMarkCache.inline.hpp"
+#include "gc/z/zMarkStack.inline.hpp"
+#include "gc/z/zMarkTerminate.inline.hpp"
+#include "gc/z/zOopClosures.inline.hpp"
+#include "gc/z/zPage.hpp"
+#include "gc/z/zPageTable.inline.hpp"
+#include "gc/z/zRootsIterator.hpp"
+#include "gc/z/zStat.hpp"
+#include "gc/z/zTask.hpp"
+#include "gc/z/zThread.hpp"
+#include "gc/z/zUtils.inline.hpp"
+#include "gc/z/zWorkers.inline.hpp"
+#include "logging/log.hpp"
+#include "oops/objArrayOop.inline.hpp"
+#include "oops/oop.inline.hpp"
+#include "runtime/atomic.hpp"
+#include "runtime/handshake.hpp"
+#include "runtime/orderAccess.hpp"
+#include "runtime/prefetch.inline.hpp"
+#include "runtime/thread.hpp"
+#include "utilities/align.hpp"
+#include "utilities/globalDefinitions.hpp"
+#include "utilities/ticks.hpp"
+
+static const ZStatSubPhase ZSubPhaseConcurrentMark("Concurrent Mark");
+static const ZStatSubPhase ZSubPhaseConcurrentMarkTryFlush("Concurrent Mark Try Flush");
+static const ZStatSubPhase ZSubPhaseConcurrentMarkIdle("Concurrent Mark Idle");
+static const ZStatSubPhase ZSubPhaseConcurrentMarkTryTerminate("Concurrent Mark Try Terminate");
+static const ZStatSubPhase ZSubPhaseMarkTryComplete("Pause Mark Try Complete");
+
+ZMark::ZMark(ZWorkers* workers, ZPageTable* pagetable) :
+    _workers(workers),
+    _pagetable(pagetable),
+    _allocator(),
+    _stripes(),
+    _terminate(),
+    _work_terminateflush(true),
+    _work_nproactiveflush(0),
+    _work_nterminateflush(0),
+    _nproactiveflush(0),
+    _nterminateflush(0),
+    _ntrycomplete(0),
+    _ncontinue(0),
+    _nworkers(0) {}
+
+size_t ZMark::calculate_nstripes(uint nworkers) const {
+  // Calculate the number of stripes from the number of workers we use,
+  // where the number of stripes must be a power of two and we want to
+  // have at least one worker per stripe.
+  const size_t nstripes = ZUtils::round_down_power_of_2(nworkers);
+  return MIN2(nstripes, ZMarkStripesMax);
+}
+
+void ZMark::prepare_mark() {
+  // Increment global sequence number to invalidate
+  // marking information for all pages.
+  ZGlobalSeqNum++;
+
+  // Reset flush/continue counters
+  _nproactiveflush = 0;
+  _nterminateflush = 0;
+  _ntrycomplete = 0;
+  _ncontinue = 0;
+
+  // Set number of workers to use
+  _nworkers = _workers->nconcurrent();
+
+  // Set number of mark stripes to use, based on number
+  // of workers we will use in the concurrent mark phase.
+  const size_t nstripes = calculate_nstripes(_nworkers);
+  _stripes.set_nstripes(nstripes);
+
+  // Update statistics
+  ZStatMark::set_at_mark_start(nstripes);
+
+  // Print worker/stripe distribution
+  LogTarget(Debug, gc, marking) log;
+  if (log.is_enabled()) {
+    log.print("Mark Worker/Stripe Distribution");
+    for (uint worker_id = 0; worker_id < _nworkers; worker_id++) {
+      const ZMarkStripe* const stripe = _stripes.stripe_for_worker(_nworkers, worker_id);
+      const size_t stripe_id = _stripes.stripe_id(stripe);
+      log.print("  Worker %u(%u) -> Stripe " SIZE_FORMAT "(" SIZE_FORMAT ")",
+                worker_id, _nworkers, stripe_id, nstripes);
+    }
+  }
+}
+
+class ZMarkRootsTask : public ZTask {
+private:
+  ZMark* const   _mark;
+  ZRootsIterator _roots;
+
+public:
+  ZMarkRootsTask(ZMark* mark) :
+      ZTask("ZMarkRootsTask"),
+      _mark(mark),
+      _roots() {}
+
+  virtual void work() {
+    ZMarkRootOopClosure cl;
+    _roots.oops_do(&cl);
+
+    // Flush and free worker stacks. Needed here since
+    // the set of workers executing during root scanning
+    // can be different from the set of workers executing
+    // during mark.
+    _mark->flush_and_free();
+  }
+};
+
+void ZMark::start() {
+  // Verification
+  if (ZVerifyMarking) {
+    verify_all_stacks_empty();
+  }
+
+  // Prepare for concurrent mark
+  prepare_mark();
+
+  // Mark roots
+  ZMarkRootsTask task(this);
+  _workers->run_parallel(&task);
+}
+
+void ZMark::prepare_work() {
+  assert(_nworkers == _workers->nconcurrent(), "Invalid number of workers");
+
+  // Set number of active workers
+  _terminate.reset(_nworkers);
+
+  // Reset flush counters
+  _work_nproactiveflush = _work_nterminateflush = 0;
+  _work_terminateflush = true;
+}
+
+void ZMark::finish_work() {
+  // Accumulate proactive/terminate flush counters
+  _nproactiveflush += _work_nproactiveflush;
+  _nterminateflush += _work_nterminateflush;
+}
+
+bool ZMark::is_array(uintptr_t addr) const {
+  return ZOop::to_oop(addr)->is_objArray();
+}
+
+void ZMark::push_partial_array(uintptr_t addr, size_t size, bool finalizable) {
+  assert(is_aligned(addr, ZMarkPartialArrayMinSize), "Address misaligned");
+  ZMarkThreadLocalStacks* const stacks = ZThreadLocalData::stacks(Thread::current());
+  ZMarkStripe* const stripe = _stripes.stripe_for_addr(addr);
+  const uintptr_t offset = ZAddress::offset(addr) >> ZMarkPartialArrayMinSizeShift;
+  const uintptr_t length = size / oopSize;
+  const ZMarkStackEntry entry(offset, length, finalizable);
+
+  log_develop_trace(gc, marking)("Array push partial: " PTR_FORMAT " (" SIZE_FORMAT "), stripe: " SIZE_FORMAT,
+                                 addr, size, _stripes.stripe_id(stripe));
+
+  stacks->push(&_allocator, &_stripes, stripe, entry, false /* publish */);
+}
+
+void ZMark::follow_small_array(uintptr_t addr, size_t size, bool finalizable) {
+  assert(size <= ZMarkPartialArrayMinSize, "Too large, should be split");
+  const size_t length = size / oopSize;
+
+  log_develop_trace(gc, marking)("Array follow small: " PTR_FORMAT " (" SIZE_FORMAT ")", addr, size);
+
+  ZBarrier::mark_barrier_on_oop_array((oop*)addr, length, finalizable);
+}
+
+void ZMark::follow_large_array(uintptr_t addr, size_t size, bool finalizable) {
+  assert(size <= (size_t)arrayOopDesc::max_array_length(T_OBJECT) * oopSize, "Too large");
+  assert(size > ZMarkPartialArrayMinSize, "Too small, should not be split");
+  const uintptr_t start = addr;
+  const uintptr_t end = start + size;
+
+  // Calculate the aligned middle start/end/size, where the middle start
+  // should always be greater than the start (hence the +1 below) to make
+  // sure we always do some follow work, not just split the array into pieces.
+  const uintptr_t middle_start = align_up(start + 1, ZMarkPartialArrayMinSize);
+  const size_t    middle_size = align_down(end - middle_start, ZMarkPartialArrayMinSize);
+  const uintptr_t middle_end = middle_start + middle_size;
+
+  log_develop_trace(gc, marking)("Array follow large: " PTR_FORMAT "-" PTR_FORMAT" (" SIZE_FORMAT "), "
+                                 "middle: " PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT ")",
+                                 start, end, size, middle_start, middle_end, middle_size);
+
+  // Push unaligned trailing part
+  if (end > middle_end) {
+    const uintptr_t trailing_addr = middle_end;
+    const size_t trailing_size = end - middle_end;
+    push_partial_array(trailing_addr, trailing_size, finalizable);
+  }
+
+  // Push aligned middle part(s)
+  uintptr_t partial_addr = middle_end;
+  while (partial_addr > middle_start) {
+    const size_t parts = 2;
+    const size_t partial_size = align_up((partial_addr - middle_start) / parts, ZMarkPartialArrayMinSize);
+    partial_addr -= partial_size;
+    push_partial_array(partial_addr, partial_size, finalizable);
+  }
+
+  // Follow leading part
+  assert(start < middle_start, "Miscalculated middle start");
+  const uintptr_t leading_addr = start;
+  const size_t leading_size = middle_start - start;
+  follow_small_array(leading_addr, leading_size, finalizable);
+}
+
+void ZMark::follow_array(uintptr_t addr, size_t size, bool finalizable) {
+  if (size <= ZMarkPartialArrayMinSize) {
+    follow_small_array(addr, size, finalizable);
+  } else {
+    follow_large_array(addr, size, finalizable);
+  }
+}
+
+void ZMark::follow_partial_array(ZMarkStackEntry entry, bool finalizable) {
+  const uintptr_t addr = ZAddress::good(entry.partial_array_offset() << ZMarkPartialArrayMinSizeShift);
+  const size_t size = entry.partial_array_length() * oopSize;
+
+  follow_array(addr, size, finalizable);
+}
+
+void ZMark::follow_array_object(objArrayOop obj, bool finalizable) {
+  const uintptr_t addr = (uintptr_t)obj->base();
+  const size_t size = (size_t)obj->length() * oopSize;
+
+  follow_array(addr, size, finalizable);
+}
+
+void ZMark::follow_object(oop obj, bool finalizable) {
+  if (finalizable) {
+    ZMarkBarrierOopClosure<true /* finalizable */> cl;
+    obj->oop_iterate(&cl);
+  } else {
+    ZMarkBarrierOopClosure<false /* finalizable */> cl;
+    obj->oop_iterate(&cl);
+  }
+}
+
+bool ZMark::try_mark_object(ZMarkCache* cache, uintptr_t addr, bool finalizable) {
+  ZPage* const page = _pagetable->get(addr);
+  if (page->is_allocating()) {
+    // Newly allocated objects are implicitly marked
+    return false;
+  }
+
+  // Try mark object
+  bool inc_live = false;
+  const bool success = page->mark_object(addr, finalizable, inc_live);
+  if (inc_live) {
+    // Update live objects/bytes for page. We use the aligned object
+    // size since that is the actual number of bytes used on the page
+    // and alignment paddings can never be reclaimed.
+    const size_t size = ZUtils::object_size(addr);
+    const size_t aligned_size = align_up(size, page->object_alignment());
+    cache->inc_live(page, aligned_size);
+  }
+
+  return success;
+}
+
+void ZMark::mark_and_follow(ZMarkCache* cache, ZMarkStackEntry entry) {
+  // Decode flags
+  const bool finalizable = entry.finalizable();
+  const bool partial_array = entry.partial_array();
+
+  if (partial_array) {
+    follow_partial_array(entry, finalizable);
+    return;
+  }
+
+  // Decode object address
+  const uintptr_t addr = entry.object_address();
+
+  if (!try_mark_object(cache, addr, finalizable)) {
+    // Already marked
+    return;
+  }
+
+  if (is_array(addr)) {
+    follow_array_object(objArrayOop(ZOop::to_oop(addr)), finalizable);
+  } else {
+    follow_object(ZOop::to_oop(addr), finalizable);
+  }
+}
+
+template <typename T>
+bool ZMark::drain(ZMarkStripe* stripe, ZMarkThreadLocalStacks* stacks, ZMarkCache* cache, T* timeout) {
+  ZMarkStackEntry entry;
+
+  // Drain stripe stacks
+  while (stacks->pop(&_allocator, &_stripes, stripe, entry)) {
+    mark_and_follow(cache, entry);
+
+    // Check timeout
+    if (timeout->has_expired()) {
+      // Timeout
+      return false;
+    }
+  }
+
+  // Success
+  return true;
+}
+
+template <typename T>
+bool ZMark::drain_and_flush(ZMarkStripe* stripe, ZMarkThreadLocalStacks* stacks, ZMarkCache* cache, T* timeout) {
+  const bool success = drain(stripe, stacks, cache, timeout);
+
+  // Flush and publish worker stacks
+  stacks->flush(&_allocator, &_stripes);
+
+  return success;
+}
+
+bool ZMark::try_steal(ZMarkStripe* stripe, ZMarkThreadLocalStacks* stacks) {
+  // Try to steal a stack from another stripe
+  for (ZMarkStripe* victim_stripe = _stripes.stripe_next(stripe);
+       victim_stripe != stripe;
+       victim_stripe = _stripes.stripe_next(victim_stripe)) {
+    ZMarkStack* const stack = victim_stripe->steal_stack();
+    if (stack != NULL) {
+      // Success, install the stolen stack
+      stacks->install(&_stripes, stripe, stack);
+      return true;
+    }
+  }
+
+  // Nothing to steal
+  return false;
+}
+
+void ZMark::idle() const {
+  ZStatTimer timer(ZSubPhaseConcurrentMarkIdle);
+  os::naked_short_sleep(1);
+}
+
+class ZMarkFlushAndFreeStacksClosure : public ThreadClosure {
+private:
+  ZMark* const _mark;
+  bool         _flushed;
+
+public:
+  ZMarkFlushAndFreeStacksClosure(ZMark* mark) :
+      _mark(mark),
+      _flushed(false) {}
+
+  void do_thread(Thread* thread) {
+    if (_mark->flush_and_free(thread)) {
+      _flushed = true;
+    }
+  }
+
+  bool flushed() const {
+    return _flushed;
+  }
+};
+
+bool ZMark::flush(bool at_safepoint) {
+  ZMarkFlushAndFreeStacksClosure cl(this);
+  if (at_safepoint) {
+    Threads::threads_do(&cl);
+  } else {
+    Handshake::execute(&cl);
+  }
+
+  // Returns true if more work is available
+  return cl.flushed() || !_stripes.is_empty();
+}
+
+bool ZMark::try_flush(volatile size_t* nflush) {
+  // Only flush if handhakes are enabled
+  if (!ThreadLocalHandshakes) {
+    return false;
+  }
+
+  Atomic::inc(nflush);
+
+  ZStatTimer timer(ZSubPhaseConcurrentMarkTryFlush);
+  return flush(false /* at_safepoint */);
+}
+
+bool ZMark::try_proactive_flush() {
+  // Only do proactive flushes from worker 0
+  if (ZThread::worker_id() != 0) {
+    return false;
+  }
+
+  if (Atomic::load(&_work_nproactiveflush) == ZMarkProactiveFlushMax ||
+      Atomic::load(&_work_nterminateflush) != 0) {
+    // Limit reached or we're trying to terminate
+    return false;
+  }
+
+  return try_flush(&_work_nproactiveflush);
+}
+
+bool ZMark::try_terminate() {
+  ZStatTimer timer(ZSubPhaseConcurrentMarkTryTerminate);
+
+  if (_terminate.enter_stage0()) {
+    // Last thread entered stage 0, flush
+    if (Atomic::load(&_work_terminateflush) &&
+        Atomic::load(&_work_nterminateflush) != ZMarkTerminateFlushMax) {
+      // Exit stage 0 to allow other threads to continue marking
+      _terminate.exit_stage0();
+
+      // Flush before termination
+      if (!try_flush(&_work_nterminateflush)) {
+        // No more work available, skip further flush attempts
+        Atomic::store(false, &_work_terminateflush);
+      }
+
+      // Don't terminate, regardless of whether we successfully
+      // flushed out more work or not. We've already exited
+      // termination stage 0, to allow other threads to continue
+      // marking, so this thread has to return false and also
+      // make another round of attempted marking.
+      return false;
+    }
+  }
+
+  for (;;) {
+    if (_terminate.enter_stage1()) {
+      // Last thread entered stage 1, terminate
+      return true;
+    }
+
+    // Idle to give the other threads
+    // a chance to enter termination.
+    idle();
+
+    if (!_terminate.try_exit_stage1()) {
+      // All workers in stage 1, terminate
+      return true;
+    }
+
+    if (_terminate.try_exit_stage0()) {
+      // More work available, don't terminate
+      return false;
+    }
+  }
+}
+
+class ZMarkNoTimeout : public StackObj {
+public:
+  bool has_expired() {
+    return false;
+  }
+};
+
+void ZMark::work_without_timeout(ZMarkCache* cache, ZMarkStripe* stripe, ZMarkThreadLocalStacks* stacks) {
+  ZStatTimer timer(ZSubPhaseConcurrentMark);
+  ZMarkNoTimeout no_timeout;
+
+  for (;;) {
+    drain_and_flush(stripe, stacks, cache, &no_timeout);
+
+    if (try_steal(stripe, stacks)) {
+      // Stole work
+      continue;
+    }
+
+    if (try_proactive_flush()) {
+      // Work available
+      continue;
+    }
+
+    if (try_terminate()) {
+      // Terminate
+      break;
+    }
+  }
+}
+
+class ZMarkTimeout : public StackObj {
+private:
+  const Ticks    _start;
+  const uint64_t _timeout;
+  const uint64_t _check_interval;
+  uint64_t       _check_at;
+  uint64_t       _check_count;
+  bool           _expired;
+
+public:
+  ZMarkTimeout(uint64_t timeout_in_millis) :
+      _start(Ticks::now()),
+      _timeout(_start.value() + TimeHelper::millis_to_counter(timeout_in_millis)),
+      _check_interval(200),
+      _check_at(_check_interval),
+      _check_count(0),
+      _expired(false) {}
+
+  ~ZMarkTimeout() {
+    const Tickspan duration = Ticks::now() - _start;
+    log_debug(gc, marking)("Mark With Timeout (%s): %s, " UINT64_FORMAT " oops, %.3fms",
+                           ZThread::name(), _expired ? "Expired" : "Completed",
+                           _check_count, TimeHelper::counter_to_millis(duration.value()));
+  }
+
+  bool has_expired() {
+    if (++_check_count == _check_at) {
+      _check_at += _check_interval;
+      if ((uint64_t)Ticks::now().value() >= _timeout) {
+        // Timeout
+        _expired = true;
+      }
+    }
+
+    return _expired;
+  }
+};
+
+void ZMark::work_with_timeout(ZMarkCache* cache, ZMarkStripe* stripe, ZMarkThreadLocalStacks* stacks, uint64_t timeout_in_millis) {
+  ZStatTimer timer(ZSubPhaseMarkTryComplete);
+  ZMarkTimeout timeout(timeout_in_millis);
+
+  for (;;) {
+    if (!drain_and_flush(stripe, stacks, cache, &timeout)) {
+      // Timed out
+      break;
+    }
+
+    if (try_steal(stripe, stacks)) {
+      // Stole work
+      continue;
+    }
+
+    // Terminate
+    break;
+  }
+}
+
+void ZMark::work(uint64_t timeout_in_millis) {
+  ZMarkCache cache(_stripes.nstripes());
+  ZMarkStripe* const stripe = _stripes.stripe_for_worker(_nworkers, ZThread::worker_id());
+  ZMarkThreadLocalStacks* const stacks = ZThreadLocalData::stacks(Thread::current());
+
+  if (timeout_in_millis == 0) {
+    work_without_timeout(&cache, stripe, stacks);
+  } else {
+    work_with_timeout(&cache, stripe, stacks, timeout_in_millis);
+  }
+
+  // Make sure stacks have been flushed
+  assert(stacks->is_empty(&_stripes), "Should be empty");
+
+  // Free remaining stacks
+  stacks->free(&_allocator);
+}
+
+class ZMarkTask : public ZTask {
+private:
+  ZMark* const   _mark;
+  const uint64_t _timeout_in_millis;
+
+public:
+  ZMarkTask(ZMark* mark, uint64_t timeout_in_millis = 0) :
+      ZTask("ZMarkTask"),
+      _mark(mark),
+      _timeout_in_millis(timeout_in_millis) {
+    _mark->prepare_work();
+  }
+
+  ~ZMarkTask() {
+    _mark->finish_work();
+  }
+
+  virtual void work() {
+    _mark->work(_timeout_in_millis);
+  }
+};
+
+void ZMark::mark() {
+  ZMarkTask task(this);
+  _workers->run_concurrent(&task);
+}
+
+bool ZMark::try_complete() {
+  _ntrycomplete++;
+
+  // Use nconcurrent number of worker threads to maintain the
+  // worker/stripe distribution used during concurrent mark.
+  ZMarkTask task(this, ZMarkCompleteTimeout);
+  _workers->run_concurrent(&task);
+
+  // Successful if all stripes are empty
+  return _stripes.is_empty();
+}
+
+bool ZMark::try_end() {
+  // Flush all mark stacks
+  if (!flush(true /* at_safepoint */)) {
+    // Mark completed
+    return true;
+  }
+
+  // Try complete marking by doing a limited
+  // amount of mark work in this phase.
+  return try_complete();
+}
+
+bool ZMark::end() {
+  // Try end marking
+  if (!try_end()) {
+    // Mark not completed
+    _ncontinue++;
+    return false;
+  }
+
+  // Verification
+  if (ZVerifyMarking) {
+    verify_all_stacks_empty();
+  }
+
+  // Update statistics
+  ZStatMark::set_at_mark_end(_nproactiveflush, _nterminateflush, _ntrycomplete, _ncontinue);
+
+  // Mark completed
+  return true;
+}
+
+void ZMark::flush_and_free() {
+  Thread* const thread = Thread::current();
+  flush_and_free(thread);
+}
+
+bool ZMark::flush_and_free(Thread* thread) {
+  ZMarkThreadLocalStacks* const stacks = ZThreadLocalData::stacks(thread);
+  const bool flushed = stacks->flush(&_allocator, &_stripes);
+  stacks->free(&_allocator);
+  return flushed;
+}
+
+class ZVerifyMarkStacksEmptyClosure : public ThreadClosure {
+private:
+  const ZMarkStripeSet* const _stripes;
+
+public:
+  ZVerifyMarkStacksEmptyClosure(const ZMarkStripeSet* stripes) :
+      _stripes(stripes) {}
+
+  void do_thread(Thread* thread) {
+    ZMarkThreadLocalStacks* const stacks = ZThreadLocalData::stacks(thread);
+    guarantee(stacks->is_empty(_stripes), "Should be empty");
+  }
+};
+
+void ZMark::verify_all_stacks_empty() const {
+  // Verify thread stacks
+  ZVerifyMarkStacksEmptyClosure cl(&_stripes);
+  Threads::threads_do(&cl);
+
+  // Verify stripe stacks
+  guarantee(_stripes.is_empty(), "Should be emtpy");
+}