mirror of
https://github.com/matrix-construct/construct
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93 lines
2.5 KiB
C++
93 lines
2.5 KiB
C++
// Matrix Construct
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//
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// Copyright (C) Matrix Construct Developers, Authors & Contributors
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// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
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//
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// Permission to use, copy, modify, and/or distribute this software for any
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// purpose with or without fee is hereby granted, provided that the above
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// copyright notice and this permission notice is present in all copies. The
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// full license for this software is available in the LICENSE file.
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#pragma once
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#define HAVE_AIO_H
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#include <linux/aio_abi.h>
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#include <ircd/asio.h>
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/// AIO context instance. Right now this is a singleton with an extern
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/// instance at fs::aioctx.
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struct ircd::fs::aio
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{
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struct request;
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/// Maximum number of events we can submit to kernel
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static constexpr const size_t &MAX_EVENTS {64};
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/// Internal semaphore for synchronization of this object
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ctx::dock dock;
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/// The semaphore value for the eventfd which we keep here.
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uint64_t semval {0};
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/// An eventfd which will be notified by the kernel; we integrate this with
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/// the ircd io_service core epoll() event loop. The EFD_SEMAPHORE flag is
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/// not used to reduce the number of triggers. We can collect multiple AIO
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/// completions after a single trigger to this fd. Because EFD_SEMAPHORE is
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/// not set, the semval which is kept above will reflect a hint for how
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/// many AIO's are done.
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asio::posix::stream_descriptor resfd;
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/// Handler to the io context we submit requests to the kernel with
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aio_context_t idp {0};
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// Callback stack invoked when the sigfd is notified of completed events.
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void handle_event(const io_event &) noexcept;
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void handle_events() noexcept;
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void handle(const boost::system::error_code &, const size_t) noexcept;
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void set_handle();
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bool wait_interrupt();
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bool interrupt();
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aio();
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~aio() noexcept;
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};
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/// Generic request control block.
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struct ircd::fs::aio::request
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:iocb
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{
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struct read;
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struct write;
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ssize_t retval {-2};
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ssize_t errcode {0};
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ctx::ctx *waiter {ctx::current};
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public:
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size_t operator()();
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void cancel();
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request(const int &fd);
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~request() noexcept;
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};
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namespace ircd::fs
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{
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const_buffer write__aio(const fd &, const const_buffer &, const write_opts &);
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const_buffer read__aio(const fd &, const mutable_buffer &, const read_opts &);
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}
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/// Read request control block
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struct ircd::fs::aio::request::read
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:request
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{
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read(const int &fd, const mutable_buffer &, const read_opts &);
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};
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/// Write request control block
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struct ircd::fs::aio::request::write
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:request
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{
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write(const int &fd, const const_buffer &, const write_opts &);
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};
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