eventloop: move timers to an event loop fd

fixes hyprwm#5481

src/managers/eventLoop/EventLoopManager.cpp

@@ -2,139 +2,82 @@
 #include "../../debug/Log.hpp"
 
 #include <algorithm>
+#include <limits>
 
 #include <sys/poll.h>
+#include <sys/timerfd.h>
+#include <time.h>
+
+#define TIMESPEC_NSEC_PER_SEC 1000000000L
+
+CEventLoopManager::CEventLoopManager() {
+ m_sTimers.timerfd = timerfd_create(CLOCK_MONOTONIC, TFD_CLOEXEC);
+}
+
+static int timerWrite(int fd, uint32_t mask, void* data) {
+ g_pEventLoopManager->onTimerFire();
+ return 1;
+}
 
 void CEventLoopManager::enterLoop(wl_display* display, wl_event_loop* wlEventLoop) {
  m_sWayland.loop = wlEventLoop;
  m_sWayland.display = display;
 
- pollfd pollfds[] = {
- {
- .fd = wl_event_loop_get_fd(wlEventLoop),
- .events = POLLIN,
- },
- };
-
- std::thread pollThr([this, &pollfds]() {
- while (!m_bTerminate) {
- int ret = poll(pollfds, 1, 5000 /* 5 seconds, reasonable. Just in case we need to terminate and the signal fails */);
-
- if (ret < 0) {
- if (errno == EINTR)
- continue;
-
- Debug::log(CRIT, "Polling fds failed with {}", errno);
- m_bTerminate = true;
- return;
- }
-
- for (size_t i = 0; i < 1; ++i) {
- if (pollfds[i].revents & POLLHUP) {
- Debug::log(CRIT, "Disconnected from pollfd id {}", i);
- m_bTerminate = true;
- return;
- }
- }
-
- if (ret != 0) {
- {
- std::lock_guard<std::mutex> lg2(m_sLoopState.eventRequestMutex);
- std::lock_guard<std::mutex> lg(m_sLoopState.loopMutex);
- m_sLoopState.event = true;
- }
- m_sLoopState.cv.notify_all();
- }
- }
- });
-
- std::thread timersThr([this]() {
- while (!m_bTerminate) {
- // calc nearest thing
-
- m_sTimers.timersMutex.lock();
- float least = 1000 * 1000 * 10; // 10s in µs
- for (auto& t : m_sTimers.timers) {
- const auto TIME = std::clamp(t->leftUs(), 0.f, INFINITY);
- if (TIME < least)
- least = TIME;
- }
- m_sTimers.timersMutex.unlock();
-
- if (least > 0) {
- std::unique_lock lk(m_sTimers.timersRqMutex);
- m_sTimers.cv.wait_for(lk, std::chrono::microseconds((int)least + 1), [this] { return m_sTimers.event; });
- m_sTimers.event = false;
- }
-
- // notify main
- {
- std::lock_guard<std::mutex> lg2(m_sLoopState.eventRequestMutex);
- std::lock_guard<std::mutex> lg(m_sLoopState.loopMutex);
- m_sLoopState.event = true;
- }
-
- m_sLoopState.cv.notify_all();
- }
- });
-
- m_sLoopState.event = true; // let it process once
-
- while (1) {
- std::unique_lock lk(m_sLoopState.eventRequestMutex);
- m_sLoopState.cv.wait_for(lk, std::chrono::milliseconds(5000), [this] { return m_sLoopState.event; });
-
- if (m_bTerminate)
- break;
-
- std::lock_guard<std::mutex> lg(m_sLoopState.loopMutex);
-
- m_sLoopState.event = false;
-
- if (pollfds[0].revents & POLLIN /* wl event loop */) {
- wl_display_flush_clients(m_sWayland.display);
- if (wl_event_loop_dispatch(m_sWayland.loop, -1) < 0) {
- m_bTerminate = true;
- break;
- }
- }
-
- // TODO: don't check timers without the timer thread requesting it
- // I tried but it didnt work :/
-
- m_sTimers.timersMutex.lock();
- auto timerscpy = m_sTimers.timers;
- m_sTimers.timersMutex.unlock();
-
- for (auto& t : timerscpy) {
- if (t->passed() && !t->cancelled())
- t->call(t);
- }
-
- if (m_bTerminate)
- break;
- }
+ wl_event_loop_add_fd(wlEventLoop, m_sTimers.timerfd, WL_EVENT_READABLE, timerWrite, nullptr);
+
+ wl_display_run(display);
 
  Debug::log(LOG, "Kicked off the event loop! :(");
+}
+
+void CEventLoopManager::onTimerFire() {
+ for (auto& t : m_sTimers.timers) {
+ if (t->passed() && !t->cancelled())
+ t->call(t);
+ }
 
- m_sTimers.event = true;
- m_sTimers.cv.notify_all();
+ nudgeTimers();
 }
 
 void CEventLoopManager::addTimer(std::shared_ptr<CEventLoopTimer> timer) {
- m_sTimers.timersMutex.lock();
  m_sTimers.timers.push_back(timer);
- m_sTimers.timersMutex.unlock();
  nudgeTimers();
 }
 
 void CEventLoopManager::removeTimer(std::shared_ptr<CEventLoopTimer> timer) {
- m_sTimers.timersMutex.lock();
  std::erase_if(m_sTimers.timers, [timer](const auto& t) { return timer == t; });
- m_sTimers.timersMutex.unlock();
+ nudgeTimers();
+}
+
+static void timespecAddNs(timespec* pTimespec, int64_t delta) {
+ int delta_ns_low = delta % TIMESPEC_NSEC_PER_SEC;
+ int delta_s_high = delta / TIMESPEC_NSEC_PER_SEC;
+
+ pTimespec->tv_sec += delta_s_high;
+
+ pTimespec->tv_nsec += (long)delta_ns_low;
+ if (pTimespec->tv_nsec >= TIMESPEC_NSEC_PER_SEC) {
+ pTimespec->tv_nsec -= TIMESPEC_NSEC_PER_SEC;
+ ++pTimespec->tv_sec;
+ }
 }
 
 void CEventLoopManager::nudgeTimers() {
- m_sTimers.event = true;
- m_sTimers.cv.notify_all();
+
+ long nextTimerUs = 10 * 1000 * 1000; // 10s
+
+ for (auto& t : m_sTimers.timers) {
+ if (const auto µs = t->leftUs(); µs < nextTimerUs)
+ nextTimerUs = µs;
+ }
+
+ nextTimerUs = std::clamp(nextTimerUs + 1, 1L, std::numeric_limits<long>::max());
+
+ timespec now;
+ clock_gettime(CLOCK_MONOTONIC, &now);
+ timespecAddNs(&now, nextTimerUs * 1000L);
+
+ itimerspec ts = {.it_value = now};
+
+ timerfd_settime(m_sTimers.timerfd, TFD_TIMER_ABSTIME, &ts, nullptr);
 }

src/managers/eventLoop/EventLoopManager.hpp

@@ -10,37 +10,27 @@
 
 class CEventLoopManager {
  public:
+ CEventLoopManager();
+
  void enterLoop(wl_display* display, wl_event_loop* wlEventLoop);
  void addTimer(std::shared_ptr<CEventLoopTimer> timer);
  void removeTimer(std::shared_ptr<CEventLoopTimer> timer);
 
+ void onTimerFire();
+
  // recalculates timers
  void nudgeTimers();
 
  private:
  struct {
  wl_event_loop* loop = nullptr;
  wl_display* display = nullptr;
- std::thread pollThread;
  } m_sWayland;
 
  struct {
- std::mutex timersMutex;
- std::mutex timersRqMutex;
  std::vector<std::shared_ptr<CEventLoopTimer>> timers;
- std::thread timerThread;
- bool event = false;
- std::condition_variable cv;
+ int timerfd = -1;
  } m_sTimers;
-
- struct {
- std::mutex loopMutex;
- std::mutex eventRequestMutex;
- bool event = false;
- std::condition_variable cv;
- } m_sLoopState;
-
- bool m_bTerminate = false;
 };
 
 inline std::unique_ptr<CEventLoopManager> g_pEventLoopManager;

src/managers/eventLoop/EventLoopTimer.cpp

@@ -1,5 +1,5 @@
 #include "EventLoopTimer.hpp"
-#include <numeric>
+#include <limits>
 #include "EventLoopManager.hpp"
 
 CEventLoopTimer::CEventLoopTimer(std::optional<std::chrono::system_clock::duration> timeout, std::function<void(std::shared_ptr<CEventLoopTimer> self, void* data)> cb_,