Initial changes for new metaspace. Only tested for Linux x64.
/*
* Copyright (c) 2019, SAP SE. All rights reserved.
* Copyright (c) 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.
*
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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_MEMORY_METASPACE_COUNTER_HPP
#define SHARE_MEMORY_METASPACE_COUNTER_HPP
#include "metaprogramming/isSigned.hpp"
#include "runtime/atomic.hpp"
#include "utilities/debug.hpp"
#include "utilities/globalDefinitions.hpp"
namespace metaspace {
// A very simple helper class which counts something, offers decrement/increment
// methods and checks for overflow/underflow on increment/decrement.
//
// (since we seem to do that alot....)
template <class T>
class AbstractCounter {
T _c;
// Only allow unsigned values for now
STATIC_ASSERT(IsSigned<T>::value == false);
public:
AbstractCounter() : _c(0) {}
T get() const { return _c; }
void increment() { assert(_c + 1 > _c, "overflow"); _c ++; }
void increment_by(T v) { assert(_c + v >= _c, "overflow"); _c += v; }
void decrement() { assert(_c - 1 < _c, "underflow"); _c --; }
void decrement_by(T v) { assert(_c - v <= _c, "underflow"); _c -= v; }
void reset() { _c = 0; }
#ifdef ASSERT
void check(T expected) const {
assert(_c == expected, "Counter mismatch: %d, expected: %d.",
(int)_c, (int)expected);
}
#endif
};
typedef AbstractCounter<size_t> SizeCounter;
typedef AbstractCounter<unsigned> IntCounter;
template <class T>
class AbstractAtomicCounter {
volatile T _c;
// Only allow unsigned values for now
STATIC_ASSERT(IsSigned<T>::value == false);
public:
AbstractAtomicCounter() : _c(0) {}
T get() const { return _c; }
void increment() { assert(_c + 1 > _c, "overflow"); Atomic::inc(&_c); }
void increment_by(T v) { assert(_c + v >= _c, "overflow"); Atomic::add(v, &_c); }
void decrement() { assert(_c - 1 < _c, "underflow"); Atomic::dec(&_c); }
void decrement_by(T v) { assert(_c - v <= _c, "underflow"); Atomic::sub(v, &_c); }
#ifdef ASSERT
void check(T expected) const {
assert(_c == expected, "Counter mismatch: %d, expected: %d.",
(int)_c, (int)expected);
}
#endif
};
typedef AbstractAtomicCounter<size_t> SizeAtomicCounter;
} // namespace metaspace
#endif // SHARE_MEMORY_METASPACE_WORDSIZECOUNTER_HPP