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4226b662cd
We only ever use private futexes, so it doesn't make sense to carry around all the complexity required for global (cross-process) futexes.
53 lines
1.3 KiB
C++
53 lines
1.3 KiB
C++
/*
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* Copyright (c) 2020, the SerenityOS developers.
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/Atomic.h>
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#include <AK/RefCounted.h>
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#include <Kernel/Locking/SpinLock.h>
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#include <Kernel/Memory/VMObject.h>
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#include <Kernel/Thread.h>
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namespace Kernel {
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class FutexQueue
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: public RefCounted<FutexQueue>
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, public Thread::BlockCondition {
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public:
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FutexQueue();
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virtual ~FutexQueue();
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u32 wake_n_requeue(u32, const Function<FutexQueue*()>&, u32, bool&, bool&);
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u32 wake_n(u32, const Optional<u32>&, bool&);
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u32 wake_all(bool&);
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template<class... Args>
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Thread::BlockResult wait_on(const Thread::BlockTimeout& timeout, Args&&... args)
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{
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return Thread::current()->block<Thread::FutexBlocker>(timeout, *this, forward<Args>(args)...);
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}
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bool queue_imminent_wait();
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void did_remove();
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bool try_remove();
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bool is_empty_and_no_imminent_waits()
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{
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ScopedSpinLock lock(m_lock);
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return is_empty_and_no_imminent_waits_locked();
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}
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bool is_empty_and_no_imminent_waits_locked();
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protected:
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virtual bool should_add_blocker(Thread::Blocker& b, void* data) override;
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private:
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size_t m_imminent_waits { 1 }; // We only create this object if we're going to be waiting, so start out with 1
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bool m_was_removed { false };
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};
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}
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