ceph/src/boost/boost/asio/detail/epoll_reactor.hpp

   1 //
   2 // detail/epoll_reactor.hpp
   3 // ~~~~~~~~~~~~~~~~~~~~~~~~
   4 //
   5 // Copyright (c) 2003-2019 Christopher M. Kohlhoff (chris at kohlhoff dot com)
   6 //
   7 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   8 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   9 //
  10
  11 #ifndef BOOST_ASIO_DETAIL_EPOLL_REACTOR_HPP
  12 #define BOOST_ASIO_DETAIL_EPOLL_REACTOR_HPP
  13
  14 #if defined(_MSC_VER) && (_MSC_VER >= 1200)
  15 # pragma once
  16 #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
  17
  18 #include <boost/asio/detail/config.hpp>
  19
  20 #if defined(BOOST_ASIO_HAS_EPOLL)
  21
  22 #include <boost/asio/detail/atomic_count.hpp>
  23 #include <boost/asio/detail/conditionally_enabled_mutex.hpp>
  24 #include <boost/asio/detail/limits.hpp>
  25 #include <boost/asio/detail/object_pool.hpp>
  26 #include <boost/asio/detail/op_queue.hpp>
  27 #include <boost/asio/detail/reactor_op.hpp>
  28 #include <boost/asio/detail/select_interrupter.hpp>
  29 #include <boost/asio/detail/socket_types.hpp>
  30 #include <boost/asio/detail/timer_queue_base.hpp>
  31 #include <boost/asio/detail/timer_queue_set.hpp>
  32 #include <boost/asio/detail/wait_op.hpp>
  33 #include <boost/asio/execution_context.hpp>
  34
  35 #if defined(BOOST_ASIO_HAS_TIMERFD)
  36 # include <sys/timerfd.h>
  37 #endif // defined(BOOST_ASIO_HAS_TIMERFD)
  38
  39 #include <boost/asio/detail/push_options.hpp>
  40
  41 namespace boost {
  42 namespace asio {
  43 namespace detail {
  44
  45 class epoll_reactor
  46   : public execution_context_service_base<epoll_reactor>
  47 {
  48 private:
  49   // The mutex type used by this reactor.
  50   typedef conditionally_enabled_mutex mutex;
  51
  52 public:
  53   enum op_types { read_op = 0, write_op = 1,
  54     connect_op = 1, except_op = 2, max_ops = 3 };
  55
  56   // Per-descriptor queues.
  57   class descriptor_state : operation
  58   {
  59     friend class epoll_reactor;
  60     friend class object_pool_access;
  61
  62     descriptor_state* next_;
  63     descriptor_state* prev_;
  64
  65     mutex mutex_;
  66     epoll_reactor* reactor_;
  67     int descriptor_;
  68     uint32_t registered_events_;
  69     op_queue<reactor_op> op_queue_[max_ops];
  70     bool try_speculative_[max_ops];
  71     bool shutdown_;
  72
  73     BOOST_ASIO_DECL descriptor_state(bool locking);
  74     void set_ready_events(uint32_t events) { task_result_ = events; }
  75     void add_ready_events(uint32_t events) { task_result_ |= events; }
  76     BOOST_ASIO_DECL operation* perform_io(uint32_t events);
  77     BOOST_ASIO_DECL static void do_complete(
  78         void* owner, operation* base,
  79         const boost::system::error_code& ec, std::size_t bytes_transferred);
  80   };
  81
  82   // Per-descriptor data.
  83   typedef descriptor_state* per_descriptor_data;
  84
  85   // Constructor.
  86   BOOST_ASIO_DECL epoll_reactor(boost::asio::execution_context& ctx);
  87
  88   // Destructor.
  89   BOOST_ASIO_DECL ~epoll_reactor();
  90
  91   // Destroy all user-defined handler objects owned by the service.
  92   BOOST_ASIO_DECL void shutdown();
  93
  94   // Recreate internal descriptors following a fork.
  95   BOOST_ASIO_DECL void notify_fork(
  96       boost::asio::execution_context::fork_event fork_ev);
  97
  98   // Initialise the task.
  99   BOOST_ASIO_DECL void init_task();
 100
 101   // Register a socket with the reactor. Returns 0 on success, system error
 102   // code on failure.
 103   BOOST_ASIO_DECL int register_descriptor(socket_type descriptor,
 104       per_descriptor_data& descriptor_data);
 105
 106   // Register a descriptor with an associated single operation. Returns 0 on
 107   // success, system error code on failure.
 108   BOOST_ASIO_DECL int register_internal_descriptor(
 109       int op_type, socket_type descriptor,
 110       per_descriptor_data& descriptor_data, reactor_op* op);
 111
 112   // Move descriptor registration from one descriptor_data object to another.
 113   BOOST_ASIO_DECL void move_descriptor(socket_type descriptor,
 114       per_descriptor_data& target_descriptor_data,
 115       per_descriptor_data& source_descriptor_data);
 116
 117   // Post a reactor operation for immediate completion.
 118   void post_immediate_completion(reactor_op* op, bool is_continuation)
 119   {
 120     scheduler_.post_immediate_completion(op, is_continuation);
 121   }
 122
 123   // Start a new operation. The reactor operation will be performed when the
 124   // given descriptor is flagged as ready, or an error has occurred.
 125   BOOST_ASIO_DECL void start_op(int op_type, socket_type descriptor,
 126       per_descriptor_data& descriptor_data, reactor_op* op,
 127       bool is_continuation, bool allow_speculative);
 128
 129   // Cancel all operations associated with the given descriptor. The
 130   // handlers associated with the descriptor will be invoked with the
 131   // operation_aborted error.
 132   BOOST_ASIO_DECL void cancel_ops(socket_type descriptor,
 133       per_descriptor_data& descriptor_data);
 134
 135   // Cancel any operations that are running against the descriptor and remove
 136   // its registration from the reactor. The reactor resources associated with
 137   // the descriptor must be released by calling cleanup_descriptor_data.
 138   BOOST_ASIO_DECL void deregister_descriptor(socket_type descriptor,
 139       per_descriptor_data& descriptor_data, bool closing);
 140
 141   // Remove the descriptor's registration from the reactor. The reactor
 142   // resources associated with the descriptor must be released by calling
 143   // cleanup_descriptor_data.
 144   BOOST_ASIO_DECL void deregister_internal_descriptor(
 145       socket_type descriptor, per_descriptor_data& descriptor_data);
 146
 147   // Perform any post-deregistration cleanup tasks associated with the
 148   // descriptor data.
 149   BOOST_ASIO_DECL void cleanup_descriptor_data(
 150       per_descriptor_data& descriptor_data);
 151
 152   // Add a new timer queue to the reactor.
 153   template <typename Time_Traits>
 154   void add_timer_queue(timer_queue<Time_Traits>& timer_queue);
 155
 156   // Remove a timer queue from the reactor.
 157   template <typename Time_Traits>
 158   void remove_timer_queue(timer_queue<Time_Traits>& timer_queue);
 159
 160   // Schedule a new operation in the given timer queue to expire at the
 161   // specified absolute time.
 162   template <typename Time_Traits>
 163   void schedule_timer(timer_queue<Time_Traits>& queue,
 164       const typename Time_Traits::time_type& time,
 165       typename timer_queue<Time_Traits>::per_timer_data& timer, wait_op* op);
 166
 167   // Cancel the timer operations associated with the given token. Returns the
 168   // number of operations that have been posted or dispatched.
 169   template <typename Time_Traits>
 170   std::size_t cancel_timer(timer_queue<Time_Traits>& queue,
 171       typename timer_queue<Time_Traits>::per_timer_data& timer,
 172       std::size_t max_cancelled = (std::numeric_limits<std::size_t>::max)());
 173
 174   // Move the timer operations associated with the given timer.
 175   template <typename Time_Traits>
 176   void move_timer(timer_queue<Time_Traits>& queue,
 177       typename timer_queue<Time_Traits>::per_timer_data& target,
 178       typename timer_queue<Time_Traits>::per_timer_data& source);
 179
 180   // Run epoll once until interrupted or events are ready to be dispatched.
 181   BOOST_ASIO_DECL void run(long usec, op_queue<operation>& ops);
 182
 183   // Interrupt the select loop.
 184   BOOST_ASIO_DECL void interrupt();
 185
 186 private:
 187   // The hint to pass to epoll_create to size its data structures.
 188   enum { epoll_size = 20000 };
 189
 190   // Create the epoll file descriptor. Throws an exception if the descriptor
 191   // cannot be created.
 192   BOOST_ASIO_DECL static int do_epoll_create();
 193
 194   // Create the timerfd file descriptor. Does not throw.
 195   BOOST_ASIO_DECL static int do_timerfd_create();
 196
 197   // Allocate a new descriptor state object.
 198   BOOST_ASIO_DECL descriptor_state* allocate_descriptor_state();
 199
 200   // Free an existing descriptor state object.
 201   BOOST_ASIO_DECL void free_descriptor_state(descriptor_state* s);
 202
 203   // Helper function to add a new timer queue.
 204   BOOST_ASIO_DECL void do_add_timer_queue(timer_queue_base& queue);
 205
 206   // Helper function to remove a timer queue.
 207   BOOST_ASIO_DECL void do_remove_timer_queue(timer_queue_base& queue);
 208
 209   // Called to recalculate and update the timeout.
 210   BOOST_ASIO_DECL void update_timeout();
 211
 212   // Get the timeout value for the epoll_wait call. The timeout value is
 213   // returned as a number of milliseconds. A return value of -1 indicates
 214   // that epoll_wait should block indefinitely.
 215   BOOST_ASIO_DECL int get_timeout(int msec);
 216
 217 #if defined(BOOST_ASIO_HAS_TIMERFD)
 218   // Get the timeout value for the timer descriptor. The return value is the
 219   // flag argument to be used when calling timerfd_settime.
 220   BOOST_ASIO_DECL int get_timeout(itimerspec& ts);
 221 #endif // defined(BOOST_ASIO_HAS_TIMERFD)
 222
 223   // The scheduler implementation used to post completions.
 224   scheduler& scheduler_;
 225
 226   // Mutex to protect access to internal data.
 227   mutex mutex_;
 228
 229   // The interrupter is used to break a blocking epoll_wait call.
 230   select_interrupter interrupter_;
 231
 232   // The epoll file descriptor.
 233   int epoll_fd_;
 234
 235   // The timer file descriptor.
 236   int timer_fd_;
 237
 238   // The timer queues.
 239   timer_queue_set timer_queues_;
 240
 241   // Whether the service has been shut down.
 242   bool shutdown_;
 243
 244   // Mutex to protect access to the registered descriptors.
 245   mutex registered_descriptors_mutex_;
 246
 247   // Keep track of all registered descriptors.
 248   object_pool<descriptor_state> registered_descriptors_;
 249
 250   // Helper class to do post-perform_io cleanup.
 251   struct perform_io_cleanup_on_block_exit;
 252   friend struct perform_io_cleanup_on_block_exit;
 253 };
 254
 255 } // namespace detail
 256 } // namespace asio
 257 } // namespace boost
 258
 259 #include <boost/asio/detail/pop_options.hpp>
 260
 261 #include <boost/asio/detail/impl/epoll_reactor.hpp>
 262 #if defined(BOOST_ASIO_HEADER_ONLY)
 263 # include <boost/asio/detail/impl/epoll_reactor.ipp>
 264 #endif // defined(BOOST_ASIO_HEADER_ONLY)
 265
 266 #endif // defined(BOOST_ASIO_HAS_EPOLL)
 267
 268 #endif // BOOST_ASIO_DETAIL_EPOLL_REACTOR_HPP