. /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   41 void register_signal_reader(int read_fd) override 126   41 void register_signal_reader(int read_fd) override
127   { 127   {
HITCBC 128   41 register_descriptor(read_fd, signal_pipe_reader_.arm()); 128   41 register_descriptor(read_fd, signal_pipe_reader_.arm());
HITCBC 129   41 } 129   41 }
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   641 inline epoll_scheduler::epoll_scheduler(capy::execution_context& ctx, int) 157   638 inline epoll_scheduler::epoll_scheduler(capy::execution_context& ctx, int)
HITCBC 158   641 : epoll_fd_(-1) 158   638 : epoll_fd_(-1)
HITCBC 159   641 , event_fd_(-1) 159   638 , event_fd_(-1)
HITCBC 160   641 , timer_fd_(-1) 160   638 , timer_fd_(-1)
HITCBC 161   1282 , event_buffer_(max_events_per_poll_) 161   1276 , event_buffer_(max_events_per_poll_)
162   { 162   {
HITCBC 163   641 epoll_fd_ = ::epoll_create1(EPOLL_CLOEXEC); 163   638 epoll_fd_ = ::epoll_create1(EPOLL_CLOEXEC);
HITCBC 164   641 if (epoll_fd_ < 0) 164   638 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   641 event_fd_ = ::eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC); 167   638 event_fd_ = ::eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
HITCBC 168   641 if (event_fd_ < 0) 168   638 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   641 timer_fd_ = ::timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK | TFD_CLOEXEC); 175   638 timer_fd_ = ::timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK | TFD_CLOEXEC);
HITCBC 176   641 if (timer_fd_ < 0) 176   638 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   641 epoll_event ev{}; 184   638 epoll_event ev{};
HITCBC 185   641 ev.events = EPOLLIN | EPOLLET; 185   638 ev.events = EPOLLIN | EPOLLET;
HITCBC 186   641 ev.data.ptr = nullptr; 186   638 ev.data.ptr = nullptr;
HITCBC 187   641 if (::epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, event_fd_, &ev) < 0) 187   638 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   641 epoll_event timer_ev{}; 196   638 epoll_event timer_ev{};
HITCBC 197   641 timer_ev.events = EPOLLIN | EPOLLERR; 197   638 timer_ev.events = EPOLLIN | EPOLLERR;
HITCBC 198   641 timer_ev.data.ptr = &timer_fd_; 198   638 timer_ev.data.ptr = &timer_fd_;
HITCBC 199   641 if (::epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, timer_fd_, &timer_ev) < 0) 199   638 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   641 timer_svc_ = &get_timer_service(ctx, *this); 208   638 timer_svc_ = &get_timer_service(ctx, *this);
HITCBC 209   641 timer_svc_->set_on_earliest_changed( 209   638 timer_svc_->set_on_earliest_changed(
HITCBC 210   5639 timer_service::callback(this, [](void* p) { 210   5313 timer_service::callback(this, [](void* p) {
HITCBC 211   4998 auto* self = static_cast<epoll_scheduler*>(p); 211   4675 auto* self = static_cast<epoll_scheduler*>(p);
HITCBC 212   4998 self->timerfd_stale_.store(true, std::memory_order_release); 212   4675 self->timerfd_stale_.store(true, std::memory_order_release);
HITCBC 213   4998 self->interrupt_reactor(); 213   4675 self->interrupt_reactor();
HITCBC 214   4998 })); 214   4675 }));
215   215  
HITCBC 216   641 get_resolver_service(ctx, *this); 216   638 get_resolver_service(ctx, *this);
HITCBC 217   641 get_signal_service(ctx, *this); 217   638 get_signal_service(ctx, *this);
HITCBC 218   641 get_stream_file_service(ctx, *this); 218   638 get_stream_file_service(ctx, *this);
HITCBC 219   641 get_random_access_file_service(ctx, *this); 219   638 get_random_access_file_service(ctx, *this);
220   220  
HITCBC 221   641 completed_ops_.push(&task_op_); 221   638 completed_ops_.push(&task_op_);
HITCBC 222   641 } 222   638 }
223   223  
HITCBC 224   1282 inline epoll_scheduler::~epoll_scheduler() 224   1276 inline epoll_scheduler::~epoll_scheduler()
225   { 225   {
HITCBC 226   641 if (timer_fd_ >= 0) 226   638 if (timer_fd_ >= 0)
HITCBC 227   641 ::close(timer_fd_); 227   638 ::close(timer_fd_);
HITCBC 228   641 if (event_fd_ >= 0) 228   638 if (event_fd_ >= 0)
HITCBC 229   641 ::close(event_fd_); 229   638 ::close(event_fd_);
HITCBC 230   641 if (epoll_fd_ >= 0) 230   638 if (epoll_fd_ >= 0)
HITCBC 231   641 ::close(epoll_fd_); 231   638 ::close(epoll_fd_);
HITCBC 232   1282 } 232   1276 }
233   233  
234   inline void 234   inline void
HITCBC 235   641 epoll_scheduler::shutdown() 235   638 epoll_scheduler::shutdown()
236   { 236   {
HITCBC 237   641 shutdown_drain(); 237   638 shutdown_drain();
238   238  
HITCBC 239   641 if (event_fd_ >= 0) 239   638 if (event_fd_ >= 0)
HITCBC 240   641 interrupt_reactor(); 240   638 interrupt_reactor();
HITCBC 241   641 } 241   638 }
242   242  
243   inline void 243   inline void
HITCBC 244   16 epoll_scheduler::configure_reactor( 244   16 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   16 reactor_scheduler::configure_reactor( 250   16 reactor_scheduler::configure_reactor(
251   max_events, budget_init, budget_max, unassisted); 251   max_events, budget_init, budget_max, unassisted);
HITCBC 252   15 event_buffer_.resize(max_events_per_poll_); 252   15 event_buffer_.resize(max_events_per_poll_);
HITCBC 253   15 } 253   15 }
254   254  
255   inline void 255   inline void
HITCBC 256   8840 epoll_scheduler::register_descriptor(int fd, reactor_descriptor_state* desc) const 256   8025 epoll_scheduler::register_descriptor(int fd, reactor_descriptor_state* desc) const
257   { 257   {
HITCBC 258   8840 epoll_event ev{}; 258   8025 epoll_event ev{};
HITCBC 259   8840 ev.events = EPOLLIN | EPOLLOUT | EPOLLET | EPOLLERR | EPOLLHUP; 259   8025 ev.events = EPOLLIN | EPOLLOUT | EPOLLET | EPOLLERR | EPOLLHUP;
HITCBC 260   8840 ev.data.ptr = desc; 260   8025 ev.data.ptr = desc;
261   261  
HITCBC 262   8840 if (::epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, fd, &ev) < 0) 262   8025 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   8840 desc->registered_events = ev.events; 265   8025 desc->registered_events = ev.events;
HITCBC 266   8840 desc->fd = fd; 266   8025 desc->fd = fd;
HITCBC 267   8840 desc->scheduler_ = this; 267   8025 desc->scheduler_ = this;
HITCBC 268   8840 desc->mutex.set_enabled(reactor_io_locking_); 268   8025 desc->mutex.set_enabled(reactor_io_locking_);
HITCBC 269   8840 desc->ready_events_.store(0, std::memory_order_relaxed); 269   8025 desc->ready_events_.store(0, std::memory_order_relaxed);
270   270  
HITCBC 271   8840 conditionally_enabled_mutex::scoped_lock lock(desc->mutex); 271   8025 conditionally_enabled_mutex::scoped_lock lock(desc->mutex);
HITCBC 272   8840 desc->impl_ref_.reset(); 272   8025 desc->impl_ref_.reset();
HITCBC 273   8840 desc->read_ready = false; 273   8025 desc->read_ready = false;
HITCBC 274   8840 desc->write_ready = false; 274   8025 desc->write_ready = false;
HITCBC 275   8840 } 275   8025 }
276   276  
277   inline void 277   inline void
HITCBC 278   8799 epoll_scheduler::deregister_descriptor(int fd) const 278   7984 epoll_scheduler::deregister_descriptor(int fd) const
279   { 279   {
HITCBC 280   8799 ::epoll_ctl(epoll_fd_, EPOLL_CTL_DEL, fd, nullptr); 280   7984 ::epoll_ctl(epoll_fd_, EPOLL_CTL_DEL, fd, nullptr);
HITCBC 281   8799 } 281   7984 }
282   282  
283   inline void 283   inline void
HITCBC 284   6155 epoll_scheduler::interrupt_reactor() const 284   5821 epoll_scheduler::interrupt_reactor() const
285   { 285   {
HITCBC 286   6155 bool expected = false; 286   5821 bool expected = false;
HITCBC 287   6155 if (eventfd_armed_.compare_exchange_strong( 287   5821 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   5210 std::uint64_t val = 1; 291   4802 std::uint64_t val = 1;
HITCBC 292   5210 [[maybe_unused]] auto r = ::write(event_fd_, &val, sizeof(val)); 292   4802 [[maybe_unused]] auto r = ::write(event_fd_, &val, sizeof(val));
293   } 293   }
HITCBC 294   6155 } 294   5821 }
295   295  
296   inline void 296   inline void
HITCBC 297   8838 epoll_scheduler::update_timerfd() const 297   8030 epoll_scheduler::update_timerfd() const
298   { 298   {
HITCBC 299   8838 auto nearest = timer_svc_->nearest_expiry(); 299   8030 auto nearest = timer_svc_->nearest_expiry();
300   300  
HITCBC 301   8838 itimerspec ts{}; 301   8030 itimerspec ts{};
HITCBC 302   8838 int flags = 0; 302   8030 int flags = 0;
303   303  
HITCBC 304   8838 if (nearest == timer_service::time_point::max()) 304   8030 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   8704 auto now = std::chrono::steady_clock::now(); 310   7897 auto now = std::chrono::steady_clock::now();
HITCBC 311   8704 if (nearest <= now) 311   7897 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   463 ts.it_value.tv_nsec = 1; 314   530 ts.it_value.tv_nsec = 1;
315   } 315   }
316   else 316   else
317   { 317   {
HITCBC 318   8241 auto nsec = std::chrono::duration_cast<std::chrono::nanoseconds>( 318   7367 auto nsec = std::chrono::duration_cast<std::chrono::nanoseconds>(
HITCBC 319   8241 nearest - now) 319   7367 nearest - now)
HITCBC 320   8241 .count(); 320   7367 .count();
HITCBC 321   8241 ts.it_value.tv_sec = nsec / 1000000000; 321   7367 ts.it_value.tv_sec = nsec / 1000000000;
HITCBC 322   8241 ts.it_value.tv_nsec = nsec % 1000000000; 322   7367 ts.it_value.tv_nsec = nsec % 1000000000;
HITCBC 323   8241 if (ts.it_value.tv_sec == 0 && ts.it_value.tv_nsec == 0) 323   7367 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   8838 if (::timerfd_settime(timer_fd_, flags, &ts, nullptr) < 0) 328   8030 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   8838 } 330   8030 }
331   331  
332   inline void 332   inline void
HITCBC 333   39328 epoll_scheduler::run_task( 333   32301 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   39328 if (task_interrupted_) 337   32301 if (task_interrupted_)
HITCBC 338   26831 timeout_ms = 0; 338   21376 timeout_ms = 0;
HITCBC 339   12497 else if (timeout_us < 0) 339   10925 else if (timeout_us < 0)
HITCBC 340   12493 timeout_ms = -1; 340   10921 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   39328 if (lock.owns_lock()) 344   32301 if (lock.owns_lock())
HITCBC 345   12499 lock.unlock(); 345   10927 lock.unlock();
346   346  
HITCBC 347   39328 task_cleanup on_exit{this, &lock, ctx}; 347   32301 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   39328 if (timerfd_stale_.exchange(false, std::memory_order_acquire)) 350   32301 if (timerfd_stale_.exchange(false, std::memory_order_acquire))
HITCBC 351   4424 update_timerfd(); 351   4020 update_timerfd();
352   352  
HITCBC 353   39328 int nfds = ::epoll_wait( 353   32301 int nfds = ::epoll_wait(
354   epoll_fd_, event_buffer_.data(), 354   epoll_fd_, event_buffer_.data(),
HITCBC 355   39328 static_cast<int>(event_buffer_.size()), timeout_ms); 355   32301 static_cast<int>(event_buffer_.size()), timeout_ms);
356   356  
HITCBC 357   39328 if (nfds < 0 && errno != EINTR) 357   32301 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   39328 bool check_timers = false; 360   32301 bool check_timers = false;
HITCBC 361   39328 ready_queue local_ops; 361   32301 ready_queue local_ops;
362   362  
HITCBC 363   87900 for (int i = 0; i < nfds; ++i) 363   73939 for (int i = 0; i < nfds; ++i)
364   { 364   {
HITCBC 365   48572 if (event_buffer_[i].data.ptr == nullptr) 365   41638 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   4569 [[maybe_unused]] auto r = ::read(event_fd_, &val, sizeof(val)); 369   4164 [[maybe_unused]] auto r = ::read(event_fd_, &val, sizeof(val));
HITCBC 370   4569 eventfd_armed_.store(false, std::memory_order_relaxed); 370   4164 eventfd_armed_.store(false, std::memory_order_relaxed);
HITCBC 371   4569 continue; 371   4164 continue;
HITCBC 372   4569 } 372   4164 }
373   373  
HITCBC 374   44003 if (event_buffer_[i].data.ptr == &timer_fd_) 374   37474 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   4414 ::read(timer_fd_, &expirations, sizeof(expirations)); 379   4010 ::read(timer_fd_, &expirations, sizeof(expirations));
HITCBC 380   4414 check_timers = true; 380   4010 check_timers = true;
HITCBC 381   4414 continue; 381   4010 continue;
HITCBC 382   4414 } 382   4010 }
383   383  
384   auto* desc = 384   auto* desc =
HITCBC 385   39589 static_cast<reactor_descriptor_state*>(event_buffer_[i].data.ptr); 385   33464 static_cast<reactor_descriptor_state*>(event_buffer_[i].data.ptr);
HITCBC 386   39589 desc->add_ready_events(event_buffer_[i].events); 386   33464 desc->add_ready_events(event_buffer_[i].events);
387   387  
HITCBC 388   39589 bool expected = false; 388   33464 bool expected = false;
HITCBC 389   39589 if (desc->is_enqueued_.compare_exchange_strong( 389   33464 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   39589 local_ops.push(desc); 393   33464 local_ops.push(desc);
394   } 394   }
395   } 395   }
396   396  
HITCBC 397   39328 if (check_timers) 397   32301 if (check_timers)
398   { 398   {
HITCBC 399   4414 timer_svc_->process_expired(); 399   4010 timer_svc_->process_expired();
HITCBC 400   4414 update_timerfd(); 400   4010 update_timerfd();
401   } 401   }
402   402  
HITCBC 403   39328 lock.lock(); 403   32301 lock.lock();
404   404  
HITCBC 405   39328 completed_ops_.splice(local_ops); 405   32301 completed_ops_.splice(local_ops);
HITCBC 406   39328 } 406   32301 }
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