| 1 | //===-- condition_variable.h ------------------------------------*- C++ -*-===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | |
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| 9 | #ifndef SCUDO_CONDITION_VARIABLE_H_ |
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| 10 | #define SCUDO_CONDITION_VARIABLE_H_ |
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| 11 | |
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| 12 | #include "condition_variable_base.h" |
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| 13 | |
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| 14 | #include "common.h" |
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| 15 | #include "platform.h" |
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| 16 | |
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| 17 | #include "condition_variable_linux.h" |
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| 18 | |
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| 19 | namespace scudo { |
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| 20 | |
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| 21 | // A default implementation of default condition variable. It doesn't do a real |
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| 22 | // `wait`, instead it spins a short amount of time only. |
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| 23 | class ConditionVariableDummy |
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| 24 | : public ConditionVariableBase<ConditionVariableDummy> { |
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| 25 | public: |
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| 26 | void notifyAllImpl(UNUSED HybridMutex &M) REQUIRES(M) {} |
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| 27 | |
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| 28 | void waitImpl(UNUSED HybridMutex &M) REQUIRES(M) { |
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| 29 | M.unlock(); |
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| 30 | |
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| 31 | constexpr u32 SpinTimes = 64; |
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| 32 | volatile u32 V = 0; |
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| 33 | for (u32 I = 0; I < SpinTimes; ++I) { |
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| 34 | u32 Tmp = V + 1; |
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| 35 | V = Tmp; |
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| 36 | } |
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| 37 | |
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| 38 | M.lock(); |
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| 39 | } |
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| 40 | }; |
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| 41 | |
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| 42 | } // namespace scudo |
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| 43 | |
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| 44 | #endif // SCUDO_CONDITION_VARIABLE_H_ |
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| 45 | |
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