Bananymous
9f4271f6d8
This moves locking to the inodes themselves which allows reducing lock times significantly. Main inodes (ext2 and tmpfs) still do contain a single big mutex that gets locked during operations but now we have the architecture to optimize these.
64 lines
1.5 KiB
C++
64 lines
1.5 KiB
C++
#include <kernel/FS/EventFD.h>
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#include <kernel/Lock/LockGuard.h>
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#include <sys/epoll.h>
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namespace Kernel
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{
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BAN::ErrorOr<BAN::RefPtr<Inode>> EventFD::create(uint64_t initval, bool semaphore)
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{
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auto* eventfd_ptr = new EventFD(initval, semaphore);
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if (eventfd_ptr == nullptr)
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return BAN::Error::from_errno(ENOMEM);
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return BAN::RefPtr<Inode>(BAN::RefPtr<EventFD>::adopt(eventfd_ptr));
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}
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BAN::ErrorOr<size_t> EventFD::read_impl(off_t, BAN::ByteSpan buffer)
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{
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if (buffer.size() < sizeof(uint64_t))
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return BAN::Error::from_errno(EINVAL);
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LockGuard _(m_mutex);
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while (m_value == 0)
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TRY(Thread::current().block_or_eintr_indefinite(m_thread_blocker, &m_mutex));
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const uint64_t read_value = m_is_semaphore ? 1 : m_value.load();
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m_value -= read_value;
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buffer.as<uint64_t>() = read_value;
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epoll_notify(EPOLLOUT);
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m_thread_blocker.unblock();
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return sizeof(uint64_t);
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}
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BAN::ErrorOr<size_t> EventFD::write_impl(off_t, BAN::ConstByteSpan buffer)
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{
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if (buffer.size() < sizeof(uint64_t))
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return BAN::Error::from_errno(EINVAL);
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const uint64_t write_value = buffer.as<const uint64_t>();
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if (write_value == UINT64_MAX)
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return BAN::Error::from_errno(EINVAL);
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LockGuard _(m_mutex);
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while (m_value + write_value < m_value)
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TRY(Thread::current().block_or_eintr_indefinite(m_thread_blocker, &m_mutex));
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m_value += write_value;
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if (m_value > 0)
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epoll_notify(EPOLLIN);
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m_thread_blocker.unblock();
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return sizeof(uint64_t);
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}
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}
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