/*

 * Copyright (c) 2003, 2019, 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 "classfile/vmSymbols.hpp"

#include "memory/allocation.inline.hpp"

#include "oops/oop.inline.hpp"

#include "runtime/handles.inline.hpp"

#include "runtime/javaCalls.hpp"

#include "runtime/orderAccess.hpp"

#include "services/lowMemoryDetector.hpp"

#include "services/management.hpp"

#include "services/memoryManager.hpp"

#include "services/memoryPool.hpp"

#include "services/memoryService.hpp"

#include "services/gcNotifier.hpp"

#include "utilities/dtrace.hpp"

MemoryManager::MemoryManager(const char* name) : _name(name) {

  _num_pools = 0;

  (void)const_cast<instanceOop&>(_memory_mgr_obj = instanceOop(NULL));

}

int MemoryManager::add_pool(MemoryPool* pool) {

  int index = _num_pools;

  assert(index < MemoryManager::max_num_pools, "_num_pools exceeds the max");

  if (index < MemoryManager::max_num_pools) {

    _pools[index] = pool;

    _num_pools++;

  }

  pool->add_manager(this);

  return index;

}

MemoryManager* MemoryManager::get_code_cache_memory_manager() {

  return new MemoryManager("CodeCacheManager");

}

MemoryManager* MemoryManager::get_metaspace_memory_manager() {

  return new MemoryManager("Metaspace Manager");

}

instanceOop MemoryManager::get_memory_manager_instance(TRAPS) {

  // Must do an acquire so as to force ordering of subsequent

  // loads from anything _memory_mgr_obj points to or implies.

  instanceOop mgr_obj = OrderAccess::load_acquire(&_memory_mgr_obj);

  if (mgr_obj == NULL) {

    // It's ok for more than one thread to execute the code up to the locked region.

    // Extra manager instances will just be gc'ed.

    Klass* k = Management::sun_management_ManagementFactoryHelper_klass(CHECK_0);

    Handle mgr_name = java_lang_String::create_from_str(name(), CHECK_0);

    JavaValue result(T_OBJECT);

    JavaCallArguments args;

    args.push_oop(mgr_name);    // Argument 1

    Symbol* method_name = NULL;

    Symbol* signature = NULL;

    if (is_gc_memory_manager()) {

      Klass* extKlass = Management::com_sun_management_internal_GarbageCollectorExtImpl_klass(CHECK_0);

      // com.sun.management.GarbageCollectorMXBean is in jdk.management module which may not be present.

      if (extKlass != NULL) {

        k = extKlass;

      }

      method_name = vmSymbols::createGarbageCollector_name();

      signature = vmSymbols::createGarbageCollector_signature();

      args.push_oop(Handle());      // Argument 2 (for future extension)

    } else {

      method_name = vmSymbols::createMemoryManager_name();

      signature = vmSymbols::createMemoryManager_signature();

    }

    InstanceKlass* ik = InstanceKlass::cast(k);

    JavaCalls::call_static(&result,

                           ik,

                           method_name,

                           signature,

                           &args,

                           CHECK_0);

    instanceOop m = (instanceOop) result.get_jobject();

    instanceHandle mgr(THREAD, m);

    {

      // Get lock before setting _memory_mgr_obj

      // since another thread may have created the instance

      MutexLocker ml(Management_lock);

      // Check if another thread has created the management object.  We reload

      // _memory_mgr_obj here because some other thread may have initialized

      // it while we were executing the code before the lock.

      //

      // The lock has done an acquire, so the load can't float above it, but

      // we need to do a load_acquire as above.

      mgr_obj = OrderAccess::load_acquire(&_memory_mgr_obj);

      if (mgr_obj != NULL) {

         return mgr_obj;

      }

      // Get the address of the object we created via call_special.

      mgr_obj = mgr();

      // Use store barrier to make sure the memory accesses associated

      // with creating the management object are visible before publishing

      // its address.  The unlock will publish the store to _memory_mgr_obj

      // because it does a release first.

      OrderAccess::release_store(&_memory_mgr_obj, mgr_obj);

    }

  }

  return mgr_obj;

}

void MemoryManager::oops_do(OopClosure* f) {

  f->do_oop((oop*) &_memory_mgr_obj);

}

GCStatInfo::GCStatInfo(int num_pools) {

  // initialize the arrays for memory usage

  _before_gc_usage_array = NEW_C_HEAP_ARRAY(MemoryUsage, num_pools, mtInternal);

  _after_gc_usage_array  = NEW_C_HEAP_ARRAY(MemoryUsage, num_pools, mtInternal);

  _usage_array_size = num_pools;

  clear();

}

GCStatInfo::~GCStatInfo() {

  FREE_C_HEAP_ARRAY(MemoryUsage*, _before_gc_usage_array);

  FREE_C_HEAP_ARRAY(MemoryUsage*, _after_gc_usage_array);

}

void GCStatInfo::set_gc_usage(int pool_index, MemoryUsage usage, bool before_gc) {

  MemoryUsage* gc_usage_array;

  if (before_gc) {

    gc_usage_array = _before_gc_usage_array;

  } else {

    gc_usage_array = _after_gc_usage_array;

  }

  gc_usage_array[pool_index] = usage;

}

void GCStatInfo::clear() {

  _index = 0;

  _start_time = 0L;

  _end_time = 0L;

  for (int i = 0; i < _usage_array_size; i++) ::new (&_before_gc_usage_array[i]) MemoryUsage();

  for (int i = 0; i < _usage_array_size; i++) ::new (&_after_gc_usage_array[i]) MemoryUsage();

}

GCMemoryManager::GCMemoryManager(const char* name, const char* gc_end_message) :

  MemoryManager(name), _gc_end_message(gc_end_message) {

  _num_collections = 0;

  _last_gc_stat = NULL;

  _last_gc_lock = new Mutex(Mutex::leaf, "_last_gc_lock", true,

                            Monitor::_safepoint_check_never);

  _current_gc_stat = NULL;

  _num_gc_threads = 1;

  _notification_enabled = false;

}

GCMemoryManager::~GCMemoryManager() {

  delete _last_gc_stat;

  delete _last_gc_lock;

  delete _current_gc_stat;

}

void GCMemoryManager::add_pool(MemoryPool* pool) {

  add_pool(pool, true);

}

void GCMemoryManager::add_pool(MemoryPool* pool, bool always_affected_by_gc) {

  int index = MemoryManager::add_pool(pool);

  _pool_always_affected_by_gc[index] = always_affected_by_gc;

}

void GCMemoryManager::initialize_gc_stat_info() {

  assert(MemoryService::num_memory_pools() > 0, "should have one or more memory pools");

  _last_gc_stat = new(ResourceObj::C_HEAP, mtGC) GCStatInfo(MemoryService::num_memory_pools());

  _current_gc_stat = new(ResourceObj::C_HEAP, mtGC) GCStatInfo(MemoryService::num_memory_pools());

  // tracking concurrent collections we need two objects: one to update, and one to

  // hold the publicly available "last (completed) gc" information.

}

void GCMemoryManager::gc_begin(bool recordGCBeginTime, bool recordPreGCUsage,

                               bool recordAccumulatedGCTime) {

  assert(_last_gc_stat != NULL && _current_gc_stat != NULL, "Just checking");

  if (recordAccumulatedGCTime) {

    _accumulated_timer.start();

  }

  // _num_collections now increases in gc_end, to count completed collections

  if (recordGCBeginTime) {

    _current_gc_stat->set_index(_num_collections+1);

    _current_gc_stat->set_start_time(Management::timestamp());

  }

  if (recordPreGCUsage) {

    // Keep memory usage of all memory pools

    for (int i = 0; i < MemoryService::num_memory_pools(); i++) {

      MemoryPool* pool = MemoryService::get_memory_pool(i);

      MemoryUsage usage = pool->get_memory_usage();

      _current_gc_stat->set_before_gc_usage(i, usage);

      HOTSPOT_MEM_POOL_GC_BEGIN(

        (char *) name(), strlen(name()),

        (char *) pool->name(), strlen(pool->name()),

        usage.init_size(), usage.used(),

        usage.committed(), usage.max_size());

    }

  }

}

// A collector MUST, even if it does not complete for some reason,

// make a TraceMemoryManagerStats object where countCollection is true,

// to ensure the current gc stat is placed in _last_gc_stat.

void GCMemoryManager::gc_end(bool recordPostGCUsage,

                             bool recordAccumulatedGCTime,

                             bool recordGCEndTime, bool countCollection,

                             GCCause::Cause cause,

                             bool allMemoryPoolsAffected) {

  if (recordAccumulatedGCTime) {

    _accumulated_timer.stop();

  }

  if (recordGCEndTime) {

    _current_gc_stat->set_end_time(Management::timestamp());

  }

  if (recordPostGCUsage) {

    int i;

    // keep the last gc statistics for all memory pools

    for (i = 0; i < MemoryService::num_memory_pools(); i++) {

      MemoryPool* pool = MemoryService::get_memory_pool(i);

      MemoryUsage usage = pool->get_memory_usage();

      HOTSPOT_MEM_POOL_GC_END(

        (char *) name(), strlen(name()),

        (char *) pool->name(), strlen(pool->name()),

        usage.init_size(), usage.used(),

        usage.committed(), usage.max_size());

      _current_gc_stat->set_after_gc_usage(i, usage);

    }

    // Set last collection usage of the memory pools managed by this collector

    for (i = 0; i < num_memory_pools(); i++) {

      MemoryPool* pool = get_memory_pool(i);

      MemoryUsage usage = pool->get_memory_usage();

      if (allMemoryPoolsAffected || pool_always_affected_by_gc(i)) {

        // Compare with GC usage threshold

        pool->set_last_collection_usage(usage);

        LowMemoryDetector::detect_after_gc_memory(pool);

      }

    }

  }

  if (countCollection) {

    _num_collections++;

    // alternately update two objects making one public when complete

    {

      MutexLocker ml(_last_gc_lock, Mutex::_no_safepoint_check_flag);

      GCStatInfo *tmp = _last_gc_stat;

      _last_gc_stat = _current_gc_stat;

      _current_gc_stat = tmp;

      // reset the current stat for diagnosability purposes

      _current_gc_stat->clear();

    }

    if (is_notification_enabled()) {

      GCNotifier::pushNotification(this, _gc_end_message, GCCause::to_string(cause));

    }

  }

}

size_t GCMemoryManager::get_last_gc_stat(GCStatInfo* dest) {

  MutexLocker ml(_last_gc_lock, Mutex::_no_safepoint_check_flag);

  if (_last_gc_stat->gc_index() != 0) {

    dest->set_index(_last_gc_stat->gc_index());

    dest->set_start_time(_last_gc_stat->start_time());

    dest->set_end_time(_last_gc_stat->end_time());

    assert(dest->usage_array_size() == _last_gc_stat->usage_array_size(),

           "Must have same array size");

    size_t len = dest->usage_array_size() * sizeof(MemoryUsage);

    memcpy(dest->before_gc_usage_array(), _last_gc_stat->before_gc_usage_array(), len);

    memcpy(dest->after_gc_usage_array(), _last_gc_stat->after_gc_usage_array(), len);

  }

  return _last_gc_stat->gc_index();

}