/*

 * Copyright (c) 2019, Red Hat, Inc. All rights reserved.

 *

 * 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.

 *

 */

#ifndef SHARE_SERVICES_THREADSTACKTRACKER_HPP

#define SHARE_SERVICES_THREADSTACKTRACKER_HPP

#if INCLUDE_NMT

#include "services/allocationSite.hpp"

#include "services/mallocSiteTable.hpp"

#include "services/nmtCommon.hpp"

#include "utilities/nativeCallStack.hpp"

#include "utilities/linkedlist.hpp"

class SimpleThreadStackSite;

class SimpleThreadStack {

  friend class SimpleThreadStackSite;

private:

  address _base;

  size_t  _size;

public:

  SimpleThreadStack() : _base(NULL), _size(0) { }

  bool equals(const SimpleThreadStack& s) const {

    return base() == s.base();

  }

  size_t  size() const { return _size; }

  address base() const { return _base; }

private:

  void set_size(size_t size)  { _size = size; }

  void set_base(address base) { _base = base; }

};

class SimpleThreadStackSite : public AllocationSite<SimpleThreadStack> {

public:

  SimpleThreadStackSite(address base, size_t size, const NativeCallStack& stack) :

    AllocationSite<SimpleThreadStack>(stack, mtThreadStack) {

    data()->set_size(size);

    data()->set_base(base);

  }

  SimpleThreadStackSite(address base, size_t size) :

    AllocationSite<SimpleThreadStack>(NativeCallStack::empty_stack(), mtThreadStack) {

    data()->set_base(base);

    data()->set_size(size);

  }

  bool equals(const SimpleThreadStackSite& mts) const {

    bool eq = base() == mts.base();

    assert(!eq || size() == mts.size(), "Must match");

    return eq;

  }

  size_t  size() const { return peek()->size(); }

  address base() const { return peek()->base(); }

};

  /*

   * Most of platforms, that hotspot support, have their thread stacks backed by

   * virtual memory by default. For these cases, thread stack tracker simply

   * delegates tracking to virtual memory tracker.

   * However, there are exceptions, (e.g. AIX), that platforms can provide stacks

   * that are not page aligned. A hypothetical VM implementation, it can provide

   * it own stacks. In these case, track_as_vm() should return false and manage

   * stack tracking by this tracker internally.

   * During memory snapshot, tracked thread stacks memory data is walked and stored

   * along with malloc'd data inside baseline. The regions are not scanned and assumed

   * all committed for now. Can add scanning phase when there is a need.

   */

class ThreadStackTracker : AllStatic {

private:

  static volatile size_t _thread_count;

  static int compare_thread_stack_base(const SimpleThreadStackSite& s1, const SimpleThreadStackSite& s2);

  static SortedLinkedList<SimpleThreadStackSite, compare_thread_stack_base>* _simple_thread_stacks;

public:

  // Late phase initialization

  static bool late_initialize(NMT_TrackingLevel level);

  static bool transition(NMT_TrackingLevel from, NMT_TrackingLevel to);

  static void new_thread_stack(void* base, size_t size, const NativeCallStack& stack);

  static void delete_thread_stack(void* base, size_t size);

  static bool   track_as_vm()  { return AIX_ONLY(false) NOT_AIX(true); }

  static size_t thread_count() { return _thread_count; }

  // Snapshot support. Piggyback thread stack data in malloc slot, NMT always handles

  // thread stack slot specially since beginning.

  static bool walk_simple_thread_stack_site(MallocSiteWalker* walker);

};

#endif // INCLUDE_NMT

#endif // SHARE_SERVICES_THREADSTACKTRACKER_HPP