src/hotspot/share/gc/g1/g1MonotonicArena.inline.hpp

/*
 * Copyright (c) 2021, 2023, Oracle and/or its affiliates. All rights reserved.
 * Copyright (c) 2021, 2022, Huawei Technologies Co., Ltd. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
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 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
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 * 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.
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#ifndef SHARE_GC_G1_G1MONOTONICARENA_INLINE_HPP
#define SHARE_GC_G1_G1MONOTONICARENA_INLINE_HPP

#include "gc/g1/g1MonotonicArena.hpp"
#include "runtime/atomic.hpp"
#include "utilities/globalCounter.inline.hpp"

inline void* G1MonotonicArena::Segment::allocate_slot() {
  if (_next_allocate >= _num_slots) {
    return nullptr;
  }
  uint result = Atomic::fetch_then_add(&_next_allocate, 1u, memory_order_relaxed);
  if (result >= _num_slots) {
    return nullptr;
  }
  void* r = _bottom + (size_t)result * _slot_size;
  return r;
}

inline G1MonotonicArena::Segment* G1MonotonicArena::SegmentFreeList::get() {
  GlobalCounter::CriticalSection cs(Thread::current());

  Segment* result = _list.pop();
  if (result != nullptr) {
    Atomic::dec(&_num_segments, memory_order_relaxed);
    Atomic::sub(&_mem_size, result->mem_size(), memory_order_relaxed);
  }
  return result;
}

#endif //SHARE_GC_G1_G1MONOTONICARENA_INLINE_HPP