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f067730f6b
The kernel's Lock class now uses a proper wait queue internally instead of just having everyone wake up regularly to try to acquire the lock. We also keep the donation mechanism, so that whenever someone tries to take the lock and fails, that thread donates the remainder of its timeslice to the current lock holder. After unlocking a Lock, the unlocking thread calls WaitQueue::wake_one, which unblocks the next thread in queue.
73 lines
1.3 KiB
C++
73 lines
1.3 KiB
C++
#pragma once
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#include <AK/Assertions.h>
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#include <AK/Atomic.h>
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#include <AK/Types.h>
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#include <Kernel/Arch/i386/CPU.h>
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#include <Kernel/KSyms.h>
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#include <Kernel/Scheduler.h>
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#include <Kernel/WaitQueue.h>
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class Thread;
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extern Thread* current;
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class Lock {
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public:
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Lock(const char* name = nullptr)
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: m_name(name)
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{
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}
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~Lock() {}
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void lock();
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void unlock();
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bool unlock_if_locked();
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const char* name() const { return m_name; }
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private:
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Atomic<bool> m_lock { false };
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u32 m_level { 0 };
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Thread* m_holder { nullptr };
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const char* m_name { nullptr };
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WaitQueue m_queue;
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};
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class Locker {
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public:
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[[gnu::always_inline]] inline explicit Locker(Lock& l)
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: m_lock(l)
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{
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lock();
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}
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[[gnu::always_inline]] inline ~Locker() { unlock(); }
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[[gnu::always_inline]] inline void unlock() { m_lock.unlock(); }
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[[gnu::always_inline]] inline void lock() { m_lock.lock(); }
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private:
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Lock& m_lock;
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};
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#define LOCKER(lock) Locker locker(lock)
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template<typename T>
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class Lockable {
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public:
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Lockable() {}
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Lockable(T&& resource)
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: m_resource(move(resource))
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{
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}
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Lock& lock() { return m_lock; }
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T& resource() { return m_resource; }
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T lock_and_copy()
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{
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LOCKER(m_lock);
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return m_resource;
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}
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private:
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T m_resource;
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Lock m_lock;
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};
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