/*

 * Copyright (c) 2001, 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/systemDictionary.hpp"

#include "gc/shared/allocTracer.hpp"

#include "gc/shared/barrierSet.hpp"

#include "gc/shared/collectedHeap.hpp"

#include "gc/shared/collectedHeap.inline.hpp"

#include "gc/shared/gcLocker.inline.hpp"

#include "gc/shared/gcHeapSummary.hpp"

#include "gc/shared/gcTrace.hpp"

#include "gc/shared/gcTraceTime.inline.hpp"

#include "gc/shared/gcWhen.hpp"

#include "gc/shared/vmGCOperations.hpp"

#include "logging/log.hpp"

#include "memory/metaspace.hpp"

#include "memory/resourceArea.hpp"

#include "oops/instanceMirrorKlass.hpp"

#include "oops/oop.inline.hpp"

#include "runtime/handles.inline.hpp"

#include "runtime/init.hpp"

#include "runtime/thread.inline.hpp"

#include "runtime/threadSMR.hpp"

#include "runtime/vmThread.hpp"

#include "services/heapDumper.hpp"

#include "utilities/align.hpp"

class ClassLoaderData;

#ifdef ASSERT

int CollectedHeap::_fire_out_of_memory_count = 0;

#endif

size_t CollectedHeap::_filler_array_max_size = 0;

template <>

void EventLogBase<GCMessage>::print(outputStream* st, GCMessage& m) {

  st->print_cr("GC heap %s", m.is_before ? "before" : "after");

  st->print_raw(m);

}

void GCHeapLog::log_heap(CollectedHeap* heap, bool before) {

  if (!should_log()) {

    return;

  }

  double timestamp = fetch_timestamp();

  MutexLockerEx ml(&_mutex, Mutex::_no_safepoint_check_flag);

  int index = compute_log_index();

  _records[index].thread = NULL; // Its the GC thread so it's not that interesting.

  _records[index].timestamp = timestamp;

  _records[index].data.is_before = before;

  stringStream st(_records[index].data.buffer(), _records[index].data.size());

  st.print_cr("{Heap %s GC invocations=%u (full %u):",

                 before ? "before" : "after",

                 heap->total_collections(),

                 heap->total_full_collections());

  heap->print_on(&st);

  st.print_cr("}");

}

VirtualSpaceSummary CollectedHeap::create_heap_space_summary() {

  size_t capacity_in_words = capacity() / HeapWordSize;

  return VirtualSpaceSummary(

    reserved_region().start(), reserved_region().start() + capacity_in_words, reserved_region().end());

}

GCHeapSummary CollectedHeap::create_heap_summary() {

  VirtualSpaceSummary heap_space = create_heap_space_summary();

  return GCHeapSummary(heap_space, used());

}

MetaspaceSummary CollectedHeap::create_metaspace_summary() {

  const MetaspaceSizes meta_space(

      MetaspaceUtils::committed_bytes(),

      MetaspaceUtils::used_bytes(),

      MetaspaceUtils::reserved_bytes());

  const MetaspaceSizes data_space(

      MetaspaceUtils::committed_bytes(Metaspace::NonClassType),

      MetaspaceUtils::used_bytes(Metaspace::NonClassType),

      MetaspaceUtils::reserved_bytes(Metaspace::NonClassType));

  const MetaspaceSizes class_space(

      MetaspaceUtils::committed_bytes(Metaspace::ClassType),

      MetaspaceUtils::used_bytes(Metaspace::ClassType),

      MetaspaceUtils::reserved_bytes(Metaspace::ClassType));

  const MetaspaceChunkFreeListSummary& ms_chunk_free_list_summary =

    MetaspaceUtils::chunk_free_list_summary(Metaspace::NonClassType);

  const MetaspaceChunkFreeListSummary& class_chunk_free_list_summary =

    MetaspaceUtils::chunk_free_list_summary(Metaspace::ClassType);

  return MetaspaceSummary(MetaspaceGC::capacity_until_GC(), meta_space, data_space, class_space,

                          ms_chunk_free_list_summary, class_chunk_free_list_summary);

}

void CollectedHeap::print_heap_before_gc() {

  Universe::print_heap_before_gc();

  if (_gc_heap_log != NULL) {

    _gc_heap_log->log_heap_before(this);

  }

}

void CollectedHeap::print_heap_after_gc() {

  Universe::print_heap_after_gc();

  if (_gc_heap_log != NULL) {

    _gc_heap_log->log_heap_after(this);

  }

}

void CollectedHeap::print_on_error(outputStream* st) const {

  st->print_cr("Heap:");

  print_extended_on(st);

  st->cr();

  _barrier_set->print_on(st);

}

void CollectedHeap::trace_heap(GCWhen::Type when, const GCTracer* gc_tracer) {

  const GCHeapSummary& heap_summary = create_heap_summary();

  gc_tracer->report_gc_heap_summary(when, heap_summary);

  const MetaspaceSummary& metaspace_summary = create_metaspace_summary();

  gc_tracer->report_metaspace_summary(when, metaspace_summary);

}

void CollectedHeap::trace_heap_before_gc(const GCTracer* gc_tracer) {

  trace_heap(GCWhen::BeforeGC, gc_tracer);

}

void CollectedHeap::trace_heap_after_gc(const GCTracer* gc_tracer) {

  trace_heap(GCWhen::AfterGC, gc_tracer);

}

// WhiteBox API support for concurrent collectors.  These are the

// default implementations, for collectors which don't support this

// feature.

bool CollectedHeap::supports_concurrent_phase_control() const {

  return false;

}

const char* const* CollectedHeap::concurrent_phases() const {

  static const char* const result[] = { NULL };

  return result;

}

bool CollectedHeap::request_concurrent_phase(const char* phase) {

  return false;

}

// Memory state functions.

CollectedHeap::CollectedHeap() :

  _barrier_set(NULL),

  _is_gc_active(false),

  _total_collections(0),

  _total_full_collections(0),

  _gc_cause(GCCause::_no_gc),

  _gc_lastcause(GCCause::_no_gc)

{

  const size_t max_len = size_t(arrayOopDesc::max_array_length(T_INT));

  const size_t elements_per_word = HeapWordSize / sizeof(jint);

  _filler_array_max_size = align_object_size(filler_array_hdr_size() +

                                             max_len / elements_per_word);

  NOT_PRODUCT(_promotion_failure_alot_count = 0;)

  NOT_PRODUCT(_promotion_failure_alot_gc_number = 0;)

  if (UsePerfData) {

    EXCEPTION_MARK;

    // create the gc cause jvmstat counters

    _perf_gc_cause = PerfDataManager::create_string_variable(SUN_GC, "cause",

                             80, GCCause::to_string(_gc_cause), CHECK);

    _perf_gc_lastcause =

                PerfDataManager::create_string_variable(SUN_GC, "lastCause",

                             80, GCCause::to_string(_gc_lastcause), CHECK);

  }

  // Create the ring log

  if (LogEvents) {

    _gc_heap_log = new GCHeapLog();

  } else {

    _gc_heap_log = NULL;

  }

}

// 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 CollectedHeap::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:

    case GCCause::_metadata_GC_threshold : {

      HandleMark hm;

      do_full_collection(false);        // don't clear all soft refs

      break;

    }

    case GCCause::_metadata_GC_clear_soft_refs: {

      HandleMark hm;

      do_full_collection(true);         // do clear all soft refs

      break;

    }

    default:

      ShouldNotReachHere(); // Unexpected use of this function

  }

}

MetaWord* CollectedHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,

                                                            size_t word_size,

                                                            Metaspace::MetadataType mdtype) {

  uint loop_count = 0;

  uint gc_count = 0;

  uint full_gc_count = 0;

  assert(!Heap_lock->owned_by_self(), "Should not be holding the Heap_lock");

  do {

    MetaWord* result = loader_data->metaspace_non_null()->allocate(word_size, mdtype);

    if (result != NULL) {

      return result;

    }

    if (GCLocker::is_active_and_needs_gc()) {

      // If the GCLocker is active, just expand and allocate.

      // If that does not succeed, wait if this thread is not

      // in a critical section itself.

      result = loader_data->metaspace_non_null()->expand_and_allocate(word_size, mdtype);

      if (result != NULL) {

        return result;

      }

      JavaThread* jthr = JavaThread::current();

      if (!jthr->in_critical()) {

        // Wait for JNI critical section to be exited

        GCLocker::stall_until_clear();

        // The GC invoked by the last thread leaving the critical

        // section will be a young collection and a full collection

        // is (currently) needed for unloading classes so continue

        // to the next iteration to get a full GC.

        continue;

      } else {

        if (CheckJNICalls) {

          fatal("Possible deadlock due to allocating while"

                " in jni critical section");

        }

        return NULL;

      }

    }

    {  // Need lock to get self consistent gc_count's

      MutexLocker ml(Heap_lock);

      gc_count      = Universe::heap()->total_collections();

      full_gc_count = Universe::heap()->total_full_collections();

    }

    // Generate a VM operation

    VM_CollectForMetadataAllocation op(loader_data,

                                       word_size,

                                       mdtype,

                                       gc_count,

                                       full_gc_count,

                                       GCCause::_metadata_GC_threshold);

    VMThread::execute(&op);

    // If GC was locked out, try again. Check before checking success because the

    // prologue could have succeeded and the GC still have been locked out.

    if (op.gc_locked()) {

      continue;

    }

    if (op.prologue_succeeded()) {

      return op.result();

    }

    loop_count++;

    if ((QueuedAllocationWarningCount > 0) &&

        (loop_count % QueuedAllocationWarningCount == 0)) {

      log_warning(gc, ergo)("satisfy_failed_metadata_allocation() retries %d times,"

                            " size=" SIZE_FORMAT, loop_count, word_size);

    }

  } while (true);  // Until a GC is done

}

void CollectedHeap::set_barrier_set(BarrierSet* barrier_set) {

  _barrier_set = barrier_set;

  BarrierSet::set_bs(barrier_set);

}

#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) {

      assert((*(intptr_t*) (addr + slot)) == ((intptr_t) badHeapWordVal),

             "Found non badHeapWordValue in pre-allocation check");

    }

  }

}

#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::allocate_from_tlab_slow(Klass* klass, Thread* thread, size_t size) {

  // Retain tlab and allocate object in shared space if

  // the amount free in the tlab is too large to discard.

  if (thread->tlab().free() > thread->tlab().refill_waste_limit()) {

    thread->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 = thread->tlab().compute_size(size);

  thread->tlab().clear_before_allocation();

  if (new_tlab_size == 0) {

    return NULL;

  }

  // Allocate a new TLAB...

  HeapWord* obj = Universe::heap()->allocate_new_tlab(new_tlab_size);

  if (obj == NULL) {

    return NULL;

  }

  AllocTracer::send_allocation_in_new_tlab(klass, obj, new_tlab_size * HeapWordSize, size * HeapWordSize, thread);

  if (ZeroTLAB) {

    // ..and clear it.

    Copy::zero_to_words(obj, new_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, new_tlab_size - hdr_size, badHeapWordVal);

#endif // ASSERT

  }

  thread->tlab().fill(obj, obj + size, new_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.

  // If we compute that the reasonable way as

  //    header_size + ((sizeof(jint) * max_jint) / HeapWordSize)

  // we'll overflow on the multiply, so we do the divide first.

  // We actually lose a little by dividing first,

  // but that just makes the TLAB  somewhat smaller than the biggest array,

  // which is fine, since we'll be able to fill that.

  size_t max_int_size = typeArrayOopDesc::header_size(T_INT) +

              sizeof(jint) *

              ((juint) max_jint / (size_t) HeapWordSize);

  return align_down(max_int_size, MinObjAlignment);

}

size_t CollectedHeap::filler_array_hdr_size() {

  return align_object_offset(arrayOopDesc::header_size(T_INT)); // align to Long

}

size_t CollectedHeap::filler_array_min_size() {

  return align_object_size(filler_array_hdr_size()); // align to MinObjAlignment

}

#ifdef ASSERT

void CollectedHeap::fill_args_check(HeapWord* start, size_t words)

{

  assert(words >= min_fill_size(), "too small to fill");

  assert(is_object_aligned(words), "unaligned size");

  assert(Universe::heap()->is_in_reserved(start), "not in heap");

  assert(Universe::heap()->is_in_reserved(start + words - 1), "not in heap");

}

void CollectedHeap::zap_filler_array(HeapWord* start, size_t words, bool zap)

{

  if (ZapFillerObjects && zap) {

    Copy::fill_to_words(start + filler_array_hdr_size(),

                        words - filler_array_hdr_size(), 0XDEAFBABE);

  }

}

#endif // ASSERT

void

CollectedHeap::fill_with_array(HeapWord* start, size_t words, bool zap)

{

  assert(words >= filler_array_min_size(), "too small for an array");

  assert(words <= filler_array_max_size(), "too big for a single object");

  const size_t payload_size = words - filler_array_hdr_size();

  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);

  DEBUG_ONLY(zap_filler_array(start, words, zap);)

}

void

CollectedHeap::fill_with_object_impl(HeapWord* start, size_t words, bool zap)

{

  assert(words <= filler_array_max_size(), "too big for a single object");

  if (words >= filler_array_min_size()) {

    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);

  }

}

void CollectedHeap::fill_with_object(HeapWord* start, size_t words, bool zap)

{

  DEBUG_ONLY(fill_args_check(start, words);)

  HandleMark hm;  // Free handles before leaving.

  fill_with_object_impl(start, words, zap);

}

void CollectedHeap::fill_with_objects(HeapWord* start, size_t words, bool zap)

{

  DEBUG_ONLY(fill_args_check(start, words);)

  HandleMark hm;  // Free handles before leaving.

  // Multiple objects may be required depending on the filler array maximum size. Fill

  // the range up to that with objects that are filler_array_max_size sized. The

  // remainder is filled with a single object.

  const size_t min = min_fill_size();

  const size_t max = filler_array_max_size();

  while (words > max) {

    const size_t cur = (words - max) >= min ? max : max - min;

    fill_with_array(start, cur, zap);

    start += cur;

    words -= cur;

  }