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