. /include/boost/corosio /native /detail /epoll /epoll_scheduler.hpp
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1   // 1   //
2   // Copyright (c) 2026 Steve Gerbino 2   // Copyright (c) 2026 Steve Gerbino
3   // Copyright (c) 2026 Michael Vandeberg 3   // Copyright (c) 2026 Michael Vandeberg
4   // 4   //
5   // Distributed under the Boost Software License, Version 1.0. (See accompanying 5   // Distributed under the Boost Software License, Version 1.0. (See accompanying
6   // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 6   // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
7   // 7   //
8   // Official repository: https://github.com/cppalliance/corosio 8   // Official repository: https://github.com/cppalliance/corosio
9   // 9   //
10   10  
11   #ifndef BOOST_COROSIO_NATIVE_DETAIL_EPOLL_EPOLL_SCHEDULER_HPP 11   #ifndef BOOST_COROSIO_NATIVE_DETAIL_EPOLL_EPOLL_SCHEDULER_HPP
12   #define BOOST_COROSIO_NATIVE_DETAIL_EPOLL_EPOLL_SCHEDULER_HPP 12   #define BOOST_COROSIO_NATIVE_DETAIL_EPOLL_EPOLL_SCHEDULER_HPP
13   13  
14   #include <boost/corosio/detail/platform.hpp> 14   #include <boost/corosio/detail/platform.hpp>
15   15  
16   #if BOOST_COROSIO_HAS_EPOLL 16   #if BOOST_COROSIO_HAS_EPOLL
17   17  
18   #include <boost/corosio/detail/config.hpp> 18   #include <boost/corosio/detail/config.hpp>
19   #include <boost/capy/ex/execution_context.hpp> 19   #include <boost/capy/ex/execution_context.hpp>
20   20  
21   #include <boost/corosio/native/detail/reactor/reactor_scheduler.hpp> 21   #include <boost/corosio/native/detail/reactor/reactor_scheduler.hpp>
22   #include <boost/corosio/native/detail/reactor/reactor_signal_pipe.hpp> 22   #include <boost/corosio/native/detail/reactor/reactor_signal_pipe.hpp>
23   23  
24   #include <boost/corosio/native/detail/epoll/epoll_traits.hpp> 24   #include <boost/corosio/native/detail/epoll/epoll_traits.hpp>
25   #include <boost/corosio/detail/timer_service.hpp> 25   #include <boost/corosio/detail/timer_service.hpp>
26   #include <boost/corosio/native/detail/make_err.hpp> 26   #include <boost/corosio/native/detail/make_err.hpp>
27   #include <boost/corosio/native/detail/posix/posix_resolver_service.hpp> 27   #include <boost/corosio/native/detail/posix/posix_resolver_service.hpp>
28   #include <boost/corosio/native/detail/posix/posix_signal_service.hpp> 28   #include <boost/corosio/native/detail/posix/posix_signal_service.hpp>
29   #include <boost/corosio/native/detail/posix/posix_stream_file_service.hpp> 29   #include <boost/corosio/native/detail/posix/posix_stream_file_service.hpp>
30   #include <boost/corosio/native/detail/posix/posix_random_access_file_service.hpp> 30   #include <boost/corosio/native/detail/posix/posix_random_access_file_service.hpp>
31   31  
32   #include <boost/corosio/detail/except.hpp> 32   #include <boost/corosio/detail/except.hpp>
33   33  
34   #include <atomic> 34   #include <atomic>
35   #include <chrono> 35   #include <chrono>
36   #include <cstdint> 36   #include <cstdint>
37   #include <mutex> 37   #include <mutex>
38   #include <vector> 38   #include <vector>
39   39  
40   #include <errno.h> 40   #include <errno.h>
41   #include <sys/epoll.h> 41   #include <sys/epoll.h>
42   #include <sys/eventfd.h> 42   #include <sys/eventfd.h>
43   #include <sys/timerfd.h> 43   #include <sys/timerfd.h>
44   #include <unistd.h> 44   #include <unistd.h>
45   45  
46   namespace boost::corosio::detail { 46   namespace boost::corosio::detail {
47   47  
48   /** Linux scheduler using epoll for I/O multiplexing. 48   /** Linux scheduler using epoll for I/O multiplexing.
49   49  
50   This scheduler implements the scheduler interface using Linux epoll 50   This scheduler implements the scheduler interface using Linux epoll
51   for efficient I/O event notification. It uses a single reactor model 51   for efficient I/O event notification. It uses a single reactor model
52   where one thread runs epoll_wait while other threads 52   where one thread runs epoll_wait while other threads
53   wait on a condition variable for handler work. This design provides: 53   wait on a condition variable for handler work. This design provides:
54   54  
55   - Handler parallelism: N posted handlers can execute on N threads 55   - Handler parallelism: N posted handlers can execute on N threads
56   - No thundering herd: condition_variable wakes exactly one thread 56   - No thundering herd: condition_variable wakes exactly one thread
57   - IOCP parity: Behavior matches Windows I/O completion port semantics 57   - IOCP parity: Behavior matches Windows I/O completion port semantics
58   58  
59   When threads call run(), they first try to execute queued handlers. 59   When threads call run(), they first try to execute queued handlers.
60   If the queue is empty and no reactor is running, one thread becomes 60   If the queue is empty and no reactor is running, one thread becomes
61   the reactor and runs epoll_wait. Other threads wait on a condition 61   the reactor and runs epoll_wait. Other threads wait on a condition
62   variable until handlers are available. 62   variable until handlers are available.
63   63  
64   @par Thread Safety 64   @par Thread Safety
65   All public member functions are thread-safe. 65   All public member functions are thread-safe.
66   */ 66   */
67   class BOOST_COROSIO_DECL epoll_scheduler final : public reactor_scheduler 67   class BOOST_COROSIO_DECL epoll_scheduler final : public reactor_scheduler
68   { 68   {
69   public: 69   public:
70   /** Construct the scheduler. 70   /** Construct the scheduler.
71   71  
72   Creates an epoll instance, eventfd for reactor interruption, 72   Creates an epoll instance, eventfd for reactor interruption,
73   and timerfd for kernel-managed timer expiry. 73   and timerfd for kernel-managed timer expiry.
74   74  
75   @param ctx Reference to the owning execution_context. 75   @param ctx Reference to the owning execution_context.
76   @param concurrency_hint Hint for expected thread count (unused). 76   @param concurrency_hint Hint for expected thread count (unused).
77   */ 77   */
78   epoll_scheduler(capy::execution_context& ctx, int concurrency_hint = -1); 78   epoll_scheduler(capy::execution_context& ctx, int concurrency_hint = -1);
79   79  
80   /// Destroy the scheduler. 80   /// Destroy the scheduler.
81   ~epoll_scheduler() override; 81   ~epoll_scheduler() override;
82   82  
83   epoll_scheduler(epoll_scheduler const&) = delete; 83   epoll_scheduler(epoll_scheduler const&) = delete;
84   epoll_scheduler& operator=(epoll_scheduler const&) = delete; 84   epoll_scheduler& operator=(epoll_scheduler const&) = delete;
85   85  
86   /// Shut down the scheduler, draining pending operations. 86   /// Shut down the scheduler, draining pending operations.
87   void shutdown() override; 87   void shutdown() override;
88   88  
89   /// Apply runtime configuration, resizing the event buffer. 89   /// Apply runtime configuration, resizing the event buffer.
90   void configure_reactor( 90   void configure_reactor(
91   unsigned max_events, 91   unsigned max_events,
92   unsigned budget_init, 92   unsigned budget_init,
93   unsigned budget_max, 93   unsigned budget_max,
94   unsigned unassisted) override; 94   unsigned unassisted) override;
95   95  
96   /** Return the epoll file descriptor. 96   /** Return the epoll file descriptor.
97   97  
98   Used by socket services to register file descriptors 98   Used by socket services to register file descriptors
99   for I/O event notification. 99   for I/O event notification.
100   100  
101   @return The epoll file descriptor. 101   @return The epoll file descriptor.
102   */ 102   */
103   int epoll_fd() const noexcept 103   int epoll_fd() const noexcept
104   { 104   {
105   return epoll_fd_; 105   return epoll_fd_;
106   } 106   }
107   107  
108   /** Register a descriptor for persistent monitoring. 108   /** Register a descriptor for persistent monitoring.
109   109  
110   The fd is registered once and stays registered until explicitly 110   The fd is registered once and stays registered until explicitly
111   deregistered. Events are dispatched via reactor_descriptor_state which 111   deregistered. Events are dispatched via reactor_descriptor_state which
112   tracks pending read/write/connect operations. 112   tracks pending read/write/connect operations.
113   113  
114   @param fd The file descriptor to register. 114   @param fd The file descriptor to register.
115   @param desc Pointer to descriptor data (stored in epoll_event.data.ptr). 115   @param desc Pointer to descriptor data (stored in epoll_event.data.ptr).
116   */ 116   */
117   void register_descriptor(int fd, reactor_descriptor_state* desc) const; 117   void register_descriptor(int fd, reactor_descriptor_state* desc) const;
118   118  
119   /** Deregister a persistently registered descriptor. 119   /** Deregister a persistently registered descriptor.
120   120  
121   @param fd The file descriptor to deregister. 121   @param fd The file descriptor to deregister.
122   */ 122   */
123   void deregister_descriptor(int fd) const; 123   void deregister_descriptor(int fd) const;
124   124  
125   /// Watch the read end of the POSIX signal self-pipe (see scheduler.hpp). 125   /// Watch the read end of the POSIX signal self-pipe (see scheduler.hpp).
HITCBC 126   51 void register_signal_reader(int read_fd) override 126   51 void register_signal_reader(int read_fd) override
127   { 127   {
HITCBC 128   51 register_descriptor(read_fd, signal_pipe_reader_.arm()); 128   51 register_descriptor(read_fd, signal_pipe_reader_.arm());
HITCBC 129   51 } 129   51 }
130   130  
131   private: 131   private:
132   void 132   void
133   run_task(lock_type& lock, context_type* ctx, 133   run_task(lock_type& lock, context_type* ctx,
134   long timeout_us) override; 134   long timeout_us) override;
135   void interrupt_reactor() const override; 135   void interrupt_reactor() const override;
136   void update_timerfd() const; 136   void update_timerfd() const;
137   137  
138   int epoll_fd_; 138   int epoll_fd_;
139   int event_fd_; 139   int event_fd_;
140   int timer_fd_; 140   int timer_fd_;
141   141  
142   // Watches the global signal self-pipe's read end (armed lazily by 142   // Watches the global signal self-pipe's read end (armed lazily by
143   // register_signal_reader on the first signal registration). 143   // register_signal_reader on the first signal registration).
144   reactor_signal_pipe_reader signal_pipe_reader_; 144   reactor_signal_pipe_reader signal_pipe_reader_;
145   145  
146   // Edge-triggered eventfd state 146   // Edge-triggered eventfd state
147   mutable std::atomic<bool> eventfd_armed_{false}; 147   mutable std::atomic<bool> eventfd_armed_{false};
148   148  
149   // Set when the earliest timer changes; flushed before epoll_wait 149   // Set when the earliest timer changes; flushed before epoll_wait
150   mutable std::atomic<bool> timerfd_stale_{false}; 150   mutable std::atomic<bool> timerfd_stale_{false};
151   151  
152   // Event buffer sized from max_events_per_poll_ (set at construction, 152   // Event buffer sized from max_events_per_poll_ (set at construction,
153   // resized by configure_reactor via io_context_options). 153   // resized by configure_reactor via io_context_options).
154   std::vector<epoll_event> event_buffer_; 154   std::vector<epoll_event> event_buffer_;
155   }; 155   };
156   156  
HITCBC 157   805 inline epoll_scheduler::epoll_scheduler(capy::execution_context& ctx, int) 157   817 inline epoll_scheduler::epoll_scheduler(capy::execution_context& ctx, int)
HITCBC 158   805 : epoll_fd_(-1) 158   817 : epoll_fd_(-1)
HITCBC 159   805 , event_fd_(-1) 159   817 , event_fd_(-1)
HITCBC 160   805 , timer_fd_(-1) 160   817 , timer_fd_(-1)
HITCBC 161   1610 , event_buffer_(max_events_per_poll_) 161   1634 , event_buffer_(max_events_per_poll_)
162   { 162   {
HITCBC 163   805 epoll_fd_ = ::epoll_create1(EPOLL_CLOEXEC); 163   817 epoll_fd_ = ::epoll_create1(EPOLL_CLOEXEC);
HITCBC 164   805 if (epoll_fd_ < 0) 164   817 if (epoll_fd_ < 0)
MISUBC 165   ✗ detail::throw_system_error(make_err(errno), "epoll_create1"); 165   ✗ detail::throw_system_error(make_err(errno), "epoll_create1");
166   166  
HITCBC 167   805 event_fd_ = ::eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC); 167   817 event_fd_ = ::eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
HITCBC 168   805 if (event_fd_ < 0) 168   817 if (event_fd_ < 0)
169   { 169   {
MISUBC 170   ✗ int errn = errno; 170   ✗ int errn = errno;
MISUBC 171   ✗ ::close(epoll_fd_); 171   ✗ ::close(epoll_fd_);
MISUBC 172   ✗ detail::throw_system_error(make_err(errn), "eventfd"); 172   ✗ detail::throw_system_error(make_err(errn), "eventfd");
173   } 173   }
174   174  
HITCBC 175   805 timer_fd_ = ::timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK | TFD_CLOEXEC); 175   817 timer_fd_ = ::timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK | TFD_CLOEXEC);
HITCBC 176   805 if (timer_fd_ < 0) 176   817 if (timer_fd_ < 0)
177   { 177   {
MISUBC 178   ✗ int errn = errno; 178   ✗ int errn = errno;
MISUBC 179   ✗ ::close(event_fd_); 179   ✗ ::close(event_fd_);
MISUBC 180   ✗ ::close(epoll_fd_); 180   ✗ ::close(epoll_fd_);
MISUBC 181   ✗ detail::throw_system_error(make_err(errn), "timerfd_create"); 181   ✗ detail::throw_system_error(make_err(errn), "timerfd_create");
182   } 182   }
183   183  
HITCBC 184   805 epoll_event ev{}; 184   817 epoll_event ev{};
HITCBC 185   805 ev.events = EPOLLIN | EPOLLET; 185   817 ev.events = EPOLLIN | EPOLLET;
HITCBC 186   805 ev.data.ptr = nullptr; 186   817 ev.data.ptr = nullptr;
HITCBC 187   805 if (::epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, event_fd_, &ev) < 0) 187   817 if (::epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, event_fd_, &ev) < 0)
188   { 188   {
MISUBC 189   ✗ int errn = errno; 189   ✗ int errn = errno;
MISUBC 190   ✗ ::close(timer_fd_); 190   ✗ ::close(timer_fd_);
MISUBC 191   ✗ ::close(event_fd_); 191   ✗ ::close(event_fd_);
MISUBC 192   ✗ ::close(epoll_fd_); 192   ✗ ::close(epoll_fd_);
MISUBC 193   ✗ detail::throw_system_error(make_err(errn), "epoll_ctl"); 193   ✗ detail::throw_system_error(make_err(errn), "epoll_ctl");
194   } 194   }
195   195  
HITCBC 196   805 epoll_event timer_ev{}; 196   817 epoll_event timer_ev{};
HITCBC 197   805 timer_ev.events = EPOLLIN | EPOLLERR; 197   817 timer_ev.events = EPOLLIN | EPOLLERR;
HITCBC 198   805 timer_ev.data.ptr = &timer_fd_; 198   817 timer_ev.data.ptr = &timer_fd_;
HITCBC 199   805 if (::epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, timer_fd_, &timer_ev) < 0) 199   817 if (::epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, timer_fd_, &timer_ev) < 0)
200   { 200   {
MISUBC 201   ✗ int errn = errno; 201   ✗ int errn = errno;
MISUBC 202   ✗ ::close(timer_fd_); 202   ✗ ::close(timer_fd_);
MISUBC 203   ✗ ::close(event_fd_); 203   ✗ ::close(event_fd_);
MISUBC 204   ✗ ::close(epoll_fd_); 204   ✗ ::close(epoll_fd_);
MISUBC 205   ✗ detail::throw_system_error(make_err(errn), "epoll_ctl (timerfd)"); 205   ✗ detail::throw_system_error(make_err(errn), "epoll_ctl (timerfd)");
206   } 206   }
207   207  
HITCBC 208   805 timer_svc_ = &get_timer_service(ctx, *this); 208   817 timer_svc_ = &get_timer_service(ctx, *this);
HITCBC 209   805 timer_svc_->set_on_earliest_changed( 209   817 timer_svc_->set_on_earliest_changed(
HITCBC 210   5777 timer_service::callback(this, [](void* p) { 210   6037 timer_service::callback(this, [](void* p) {
HITCBC 211   4972 auto* self = static_cast<epoll_scheduler*>(p); 211   5220 auto* self = static_cast<epoll_scheduler*>(p);
HITCBC 212   4972 self->timerfd_stale_.store(true, std::memory_order_release); 212   5220 self->timerfd_stale_.store(true, std::memory_order_release);
HITCBC 213   4972 self->interrupt_reactor(); 213   5220 self->interrupt_reactor();
HITCBC 214   4972 })); 214   5220 }));
215   215  
HITCBC 216   805 get_resolver_service(ctx, *this); 216   817 get_resolver_service(ctx, *this);
HITCBC 217   805 get_signal_service(ctx, *this); 217   817 get_signal_service(ctx, *this);
HITCBC 218   805 get_stream_file_service(ctx, *this); 218   817 get_stream_file_service(ctx, *this);
HITCBC 219   805 get_random_access_file_service(ctx, *this); 219   817 get_random_access_file_service(ctx, *this);
220   220  
HITCBC 221   805 completed_ops_.push(&task_op_); 221   817 completed_ops_.push(&task_op_);
HITCBC 222   805 } 222   817 }
223   223  
HITCBC 224   1610 inline epoll_scheduler::~epoll_scheduler() 224   1634 inline epoll_scheduler::~epoll_scheduler()
225   { 225   {
HITCBC 226   805 if (timer_fd_ >= 0) 226   817 if (timer_fd_ >= 0)
HITCBC 227   805 ::close(timer_fd_); 227   817 ::close(timer_fd_);
HITCBC 228   805 if (event_fd_ >= 0) 228   817 if (event_fd_ >= 0)
HITCBC 229   805 ::close(event_fd_); 229   817 ::close(event_fd_);
HITCBC 230   805 if (epoll_fd_ >= 0) 230   817 if (epoll_fd_ >= 0)
HITCBC 231   805 ::close(epoll_fd_); 231   817 ::close(epoll_fd_);
HITCBC 232   1610 } 232   1634 }
233   233  
234   inline void 234   inline void
HITCBC 235   805 epoll_scheduler::shutdown() 235   817 epoll_scheduler::shutdown()
236   { 236   {
HITCBC 237   805 shutdown_drain(); 237   817 shutdown_drain();
238   238  
HITCBC 239   805 if (event_fd_ >= 0) 239   817 if (event_fd_ >= 0)
HITCBC 240   805 interrupt_reactor(); 240   817 interrupt_reactor();
HITCBC 241   805 } 241   817 }
242   242  
243   inline void 243   inline void
HITCBC 244   19 epoll_scheduler::configure_reactor( 244   19 epoll_scheduler::configure_reactor(
245   unsigned max_events, 245   unsigned max_events,
246   unsigned budget_init, 246   unsigned budget_init,
247   unsigned budget_max, 247   unsigned budget_max,
248   unsigned unassisted) 248   unsigned unassisted)
249   { 249   {
HITCBC 250   19 reactor_scheduler::configure_reactor( 250   19 reactor_scheduler::configure_reactor(
251   max_events, budget_init, budget_max, unassisted); 251   max_events, budget_init, budget_max, unassisted);
HITCBC 252   18 event_buffer_.resize(max_events_per_poll_); 252   18 event_buffer_.resize(max_events_per_poll_);
HITCBC 253   18 } 253   18 }
254   254  
255   inline void 255   inline void
HITCBC 256   8827 epoll_scheduler::register_descriptor(int fd, reactor_descriptor_state* desc) const 256   9406 epoll_scheduler::register_descriptor(int fd, reactor_descriptor_state* desc) const
257   { 257   {
HITCBC 258   8827 epoll_event ev{}; 258   9406 epoll_event ev{};
HITCBC 259   8827 ev.events = EPOLLIN | EPOLLOUT | EPOLLET | EPOLLERR | EPOLLHUP; 259   9406 ev.events = EPOLLIN | EPOLLOUT | EPOLLET | EPOLLERR | EPOLLHUP;
HITCBC 260   8827 ev.data.ptr = desc; 260   9406 ev.data.ptr = desc;
261   261  
HITCBC 262   8827 if (::epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, fd, &ev) < 0) 262   9406 if (::epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, fd, &ev) < 0)
MISUBC 263   ✗ detail::throw_system_error(make_err(errno), "epoll_ctl (register)"); 263   ✗ detail::throw_system_error(make_err(errno), "epoll_ctl (register)");
264   264  
HITCBC 265   8827 desc->registered_events = ev.events; 265   9406 desc->registered_events = ev.events;
HITCBC 266   8827 desc->fd = fd; 266   9406 desc->fd = fd;
HITCBC 267   8827 desc->scheduler_ = this; 267   9406 desc->scheduler_ = this;
HITCBC 268   8827 desc->mutex.set_enabled(reactor_io_locking_); 268   9406 desc->mutex.set_enabled(reactor_io_locking_);
HITCBC 269   8827 desc->ready_events_.store(0, std::memory_order_relaxed); 269   9406 desc->ready_events_.store(0, std::memory_order_relaxed);
270   270  
HITCBC 271   8827 conditionally_enabled_mutex::scoped_lock lock(desc->mutex); 271   9406 conditionally_enabled_mutex::scoped_lock lock(desc->mutex);
HITCBC 272   8827 desc->impl_ref_.reset(); 272   9406 desc->impl_ref_.reset();
HITCBC 273   8827 desc->read_ready = false; 273   9406 desc->read_ready = false;
HITCBC 274   8827 desc->write_ready = false; 274   9406 desc->write_ready = false;
HITCBC 275   8827 } 275   9406 }
276   276  
277   inline void 277   inline void
HITCBC 278   8776 epoll_scheduler::deregister_descriptor(int fd) const 278   9355 epoll_scheduler::deregister_descriptor(int fd) const
279   { 279   {
HITCBC 280   8776 ::epoll_ctl(epoll_fd_, EPOLL_CTL_DEL, fd, nullptr); 280   9355 ::epoll_ctl(epoll_fd_, EPOLL_CTL_DEL, fd, nullptr);
HITCBC 281   8776 } 281   9355 }
282   282  
283   inline void 283   inline void
HITCBC 284   6499 epoll_scheduler::interrupt_reactor() const 284   6771 epoll_scheduler::interrupt_reactor() const
285   { 285   {
HITCBC 286   6499 bool expected = false; 286   6771 bool expected = false;
HITCBC 287   6499 if (eventfd_armed_.compare_exchange_strong( 287   6771 if (eventfd_armed_.compare_exchange_strong(
288   expected, true, std::memory_order_release, 288   expected, true, std::memory_order_release,
289   std::memory_order_relaxed)) 289   std::memory_order_relaxed))
290   { 290   {
HITCBC 291   5356 std::uint64_t val = 1; 291   5661 std::uint64_t val = 1;
HITCBC 292   5356 [[maybe_unused]] auto r = ::write(event_fd_, &val, sizeof(val)); 292   5661 [[maybe_unused]] auto r = ::write(event_fd_, &val, sizeof(val));
293   } 293   }
HITCBC 294   6499 } 294   6771 }
295   295  
296   inline void 296   inline void
HITCBC 297   8649 epoll_scheduler::update_timerfd() const 297   9231 epoll_scheduler::update_timerfd() const
298   { 298   {
HITCBC 299   8649 auto nearest = timer_svc_->nearest_expiry(); 299   9231 auto nearest = timer_svc_->nearest_expiry();
300   300  
HITCBC 301   8649 itimerspec ts{}; 301   9231 itimerspec ts{};
HITCBC 302   8649 int flags = 0; 302   9231 int flags = 0;
303   303  
HITCBC 304   8649 if (nearest == timer_service::time_point::max()) 304   9231 if (nearest == timer_service::time_point::max())
305   { 305   {
306   // No timers — disarm by setting to 0 (relative) 306   // No timers — disarm by setting to 0 (relative)
307   } 307   }
308   else 308   else
309   { 309   {
HITCBC 310   8486 auto now = std::chrono::steady_clock::now(); 310   9060 auto now = std::chrono::steady_clock::now();
HITCBC 311   8486 if (nearest <= now) 311   9060 if (nearest <= now)
312   { 312   {
313   // Use 1ns instead of 0 — zero disarms the timerfd 313   // Use 1ns instead of 0 — zero disarms the timerfd
HITCBC 314   764 ts.it_value.tv_nsec = 1; 314   1034 ts.it_value.tv_nsec = 1;
315   } 315   }
316   else 316   else
317   { 317   {
HITCBC 318   7722 auto nsec = std::chrono::duration_cast<std::chrono::nanoseconds>( 318   8026 auto nsec = std::chrono::duration_cast<std::chrono::nanoseconds>(
HITCBC 319   7722 nearest - now) 319   8026 nearest - now)
HITCBC 320   7722 .count(); 320   8026 .count();
HITCBC 321   7722 ts.it_value.tv_sec = nsec / 1000000000; 321   8026 ts.it_value.tv_sec = nsec / 1000000000;
HITCBC 322   7722 ts.it_value.tv_nsec = nsec % 1000000000; 322   8026 ts.it_value.tv_nsec = nsec % 1000000000;
HITCBC 323   7722 if (ts.it_value.tv_sec == 0 && ts.it_value.tv_nsec == 0) 323   8026 if (ts.it_value.tv_sec == 0 && ts.it_value.tv_nsec == 0)
MISUBC 324   ✗ ts.it_value.tv_nsec = 1; 324   ✗ ts.it_value.tv_nsec = 1;
325   } 325   }
326   } 326   }
327   327  
HITCBC 328   8649 if (::timerfd_settime(timer_fd_, flags, &ts, nullptr) < 0) 328   9231 if (::timerfd_settime(timer_fd_, flags, &ts, nullptr) < 0)
MISUBC 329   ✗ detail::throw_system_error(make_err(errno), "timerfd_settime"); 329   ✗ detail::throw_system_error(make_err(errno), "timerfd_settime");
HITCBC 330   8649 } 330   9231 }
331   331  
332   inline void 332   inline void
HITCBC 333   47373 epoll_scheduler::run_task( 333   40232 epoll_scheduler::run_task(
334   lock_type& lock, context_type* ctx, long timeout_us) 334   lock_type& lock, context_type* ctx, long timeout_us)
335   { 335   {
336   int timeout_ms; 336   int timeout_ms;
HITCBC 337   47373 if (task_interrupted_) 337   40232 if (task_interrupted_)
HITCBC 338   35328 timeout_ms = 0; 338   27659 timeout_ms = 0;
HITCBC 339   12045 else if (timeout_us < 0) 339   12573 else if (timeout_us < 0)
HITCBC 340   12041 timeout_ms = -1; 340   12569 timeout_ms = -1;
341   else 341   else
HITCBC 342   4 timeout_ms = static_cast<int>((timeout_us + 999) / 1000); 342   4 timeout_ms = static_cast<int>((timeout_us + 999) / 1000);
343   343  
HITCBC 344   47373 if (lock.owns_lock()) 344   40232 if (lock.owns_lock())
HITCBC 345   12047 lock.unlock(); 345   12575 lock.unlock();
346   346  
HITCBC 347   47373 task_cleanup on_exit{this, &lock, ctx}; 347   40232 task_cleanup on_exit{this, &lock, ctx};
348   348  
349   // Flush deferred timerfd programming before blocking 349   // Flush deferred timerfd programming before blocking
HITCBC 350   47373 if (timerfd_stale_.exchange(false, std::memory_order_acquire)) 350   40232 if (timerfd_stale_.exchange(false, std::memory_order_acquire))
HITCBC 351   4332 update_timerfd(); 351   4622 update_timerfd();
352   352  
HITCBC 353   47373 int nfds = ::epoll_wait( 353   40232 int nfds = ::epoll_wait(
354   epoll_fd_, event_buffer_.data(), 354   epoll_fd_, event_buffer_.data(),
HITCBC 355   47373 static_cast<int>(event_buffer_.size()), timeout_ms); 355   40232 static_cast<int>(event_buffer_.size()), timeout_ms);
356   356  
HITCBC 357   47373 if (nfds < 0 && errno != EINTR) 357   40232 if (nfds < 0 && errno != EINTR)
MISUBC 358   ✗ detail::throw_system_error(make_err(errno), "epoll_wait"); 358   ✗ detail::throw_system_error(make_err(errno), "epoll_wait");
359   359  
HITCBC 360   47373 bool check_timers = false; 360   40232 bool check_timers = false;
HITCBC 361   47373 ready_queue local_ops; 361   40232 ready_queue local_ops;
362   362  
HITCBC 363   108047 for (int i = 0; i < nfds; ++i) 363   90648 for (int i = 0; i < nfds; ++i)
364   { 364   {
HITCBC 365   60674 if (event_buffer_[i].data.ptr == nullptr) 365   50416 if (event_buffer_[i].data.ptr == nullptr)
366   { 366   {
367   std::uint64_t val; 367   std::uint64_t val;
368   // NOLINTNEXTLINE(clang-analyzer-unix.BlockInCriticalSection) 368   // NOLINTNEXTLINE(clang-analyzer-unix.BlockInCriticalSection)
HITCBC 369   4551 [[maybe_unused]] auto r = ::read(event_fd_, &val, sizeof(val)); 369   4844 [[maybe_unused]] auto r = ::read(event_fd_, &val, sizeof(val));
HITCBC 370   4551 eventfd_armed_.store(false, std::memory_order_relaxed); 370   4844 eventfd_armed_.store(false, std::memory_order_relaxed);
HITCBC 371   4551 continue; 371   4844 continue;
HITCBC 372   4551 } 372   4844 }
373   373  
HITCBC 374   56123 if (event_buffer_[i].data.ptr == &timer_fd_) 374   45572 if (event_buffer_[i].data.ptr == &timer_fd_)
375   { 375   {
376   std::uint64_t expirations; 376   std::uint64_t expirations;
377   // NOLINTNEXTLINE(clang-analyzer-unix.BlockInCriticalSection) 377   // NOLINTNEXTLINE(clang-analyzer-unix.BlockInCriticalSection)
378   [[maybe_unused]] auto r = 378   [[maybe_unused]] auto r =
HITCBC 379   4317 ::read(timer_fd_, &expirations, sizeof(expirations)); 379   4609 ::read(timer_fd_, &expirations, sizeof(expirations));
HITCBC 380   4317 check_timers = true; 380   4609 check_timers = true;
HITCBC 381   4317 continue; 381   4609 continue;
HITCBC 382   4317 } 382   4609 }
383   383  
384   auto* desc = 384   auto* desc =
HITCBC 385   51806 static_cast<reactor_descriptor_state*>(event_buffer_[i].data.ptr); 385   40963 static_cast<reactor_descriptor_state*>(event_buffer_[i].data.ptr);
HITCBC 386   51806 desc->add_ready_events(event_buffer_[i].events); 386   40963 desc->add_ready_events(event_buffer_[i].events);
387   387  
HITCBC 388   51806 bool expected = false; 388   40963 bool expected = false;
HITCBC 389   51806 if (desc->is_enqueued_.compare_exchange_strong( 389   40963 if (desc->is_enqueued_.compare_exchange_strong(
390   expected, true, std::memory_order_release, 390   expected, true, std::memory_order_release,
391   std::memory_order_relaxed)) 391   std::memory_order_relaxed))
392   { 392   {
HITCBC 393   51806 local_ops.push(desc); 393   40963 local_ops.push(desc);
394   } 394   }
395   } 395   }
396   396  
HITCBC 397   47373 if (check_timers) 397   40232 if (check_timers)
398   { 398   {
HITCBC 399   4317 timer_svc_->process_expired(); 399   4609 timer_svc_->process_expired();
HITCBC 400   4317 update_timerfd(); 400   4609 update_timerfd();
401   } 401   }
402   402  
HITCBC 403   47373 lock.lock(); 403   40232 lock.lock();
404   404  
HITCBC 405   47373 completed_ops_.splice(local_ops); 405   40232 completed_ops_.splice(local_ops);
HITCBC 406   47373 } 406   40232 }
407   407  
408   } // namespace boost::corosio::detail 408   } // namespace boost::corosio::detail
409   409  
410   #endif // BOOST_COROSIO_HAS_EPOLL 410   #endif // BOOST_COROSIO_HAS_EPOLL
411   411  
412   #endif // BOOST_COROSIO_NATIVE_DETAIL_EPOLL_EPOLL_SCHEDULER_HPP 412   #endif // BOOST_COROSIO_NATIVE_DETAIL_EPOLL_EPOLL_SCHEDULER_HPP