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Diffstat (limited to 'Kernel/Tasks/FutexQueue.h')
-rw-r--r-- | Kernel/Tasks/FutexQueue.h | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/Kernel/Tasks/FutexQueue.h b/Kernel/Tasks/FutexQueue.h new file mode 100644 index 0000000000..3b53c25ee3 --- /dev/null +++ b/Kernel/Tasks/FutexQueue.h @@ -0,0 +1,50 @@ +/* + * Copyright (c) 2020, the SerenityOS developers. + * + * SPDX-License-Identifier: BSD-2-Clause + */ + +#pragma once + +#include <AK/AtomicRefCounted.h> +#include <Kernel/Locking/Spinlock.h> +#include <Kernel/Tasks/Thread.h> + +namespace Kernel { + +class FutexQueue final + : public AtomicRefCounted<FutexQueue> + , public Thread::BlockerSet { +public: + FutexQueue(); + virtual ~FutexQueue(); + + ErrorOr<u32> wake_n_requeue(u32, Function<ErrorOr<FutexQueue*>()> const&, u32, bool&, bool&); + u32 wake_n(u32, Optional<u32> const&, bool&); + u32 wake_all(bool&); + + template<class... Args> + Thread::BlockResult wait_on(Thread::BlockTimeout const& timeout, Args&&... args) + { + return Thread::current()->block<Thread::FutexBlocker>(timeout, *this, forward<Args>(args)...); + } + + bool queue_imminent_wait(); + bool try_remove(); + + bool is_empty_and_no_imminent_waits() + { + SpinlockLocker lock(m_lock); + return is_empty_and_no_imminent_waits_locked(); + } + bool is_empty_and_no_imminent_waits_locked(); + +protected: + virtual bool should_add_blocker(Thread::Blocker& b, void*) override; + +private: + size_t m_imminent_waits { 1 }; // We only create this object if we're going to be waiting, so start out with 1 + bool m_was_removed { false }; +}; + +} |