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//===-- condition_variable.h ------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef SCUDO_CONDITION_VARIABLE_H_
#define SCUDO_CONDITION_VARIABLE_H_
#include "condition_variable_base.h"
#include "common.h"
#include "platform.h"
#include "condition_variable_linux.h"
namespace scudo {
// A default implementation of default condition variable. It doesn't do a real
// `wait`, instead it spins a short amount of time only.
class ConditionVariableDummy
: public ConditionVariableBase<ConditionVariableDummy> {
public:
void notifyAllImpl(UNUSED HybridMutex &M) REQUIRES(M) {}
void waitImpl(UNUSED HybridMutex &M) REQUIRES(M) {
M.unlock();
constexpr u32 SpinTimes = 64;
volatile u32 V = 0;
for (u32 I = 0; I < SpinTimes; ++I) {
u32 Tmp = V + 1;
V = Tmp;
}
M.lock();
}
};
template <typename Config, typename = const bool>
struct ConditionVariableState {
static constexpr bool enabled() { return false; }
// This is only used for compilation purpose so that we won't end up having
// many conditional compilations. If you want to use `ConditionVariableDummy`,
// define `ConditionVariableT` in your allocator configuration. See
// allocator_config.h for more details.
using ConditionVariableT = ConditionVariableDummy;
};
template <typename Config>
struct ConditionVariableState<Config, decltype(Config::UseConditionVariable)> {
static constexpr bool enabled() { return Config::UseConditionVariable; }
using ConditionVariableT = typename Config::ConditionVariableT;
};
} // namespace scudo
#endif // SCUDO_CONDITION_VARIABLE_H_
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