Since now thread_usleep(0) can also bring errno of interruption, it s…

…hould be working

io/epoll.cpp

@@ -302,26 +302,6 @@ ok: entry.interests |= eint;
  thread* current = CURRENT;
  int ret = add_interest({fd, interest | ONE_SHOT, current});
  if (ret < 0) LOG_ERROR_RETURN(0, -1, "failed to add event interest");
- // if timeout is just simple 0, wait for a tiny little moment
- // so that events can be collect.
- if (timeout.expired()) {
- ret = -1;
- wait_for_events(
- 0,
- [current, &ret](void* data) __INLINE__ {
- if ((thread*)data == current) {
- ret = 0;
- } else {
- thread_interrupt((thread*)data, EOK);
- }
- },
- [&]() __INLINE__ { return true; });
- if (ret < 0) {
- rm_interest({fd, interest, 0});
- errno = ETIMEDOUT;
- }
- return ret;
- }
  ret = thread_usleep(timeout);
  ERRNO err;
  if (ret == -1 && err.no == EOK) {

io/kqueue.cpp

@@ -122,20 +122,6 @@ class KQueue : public MasterEventEngine, public CascadingEventEngine, public Res
  auto current = CURRENT;
  int ret = enqueue(fd, ev, EV_ADD | EV_ONESHOT, 0, current);
  if (ret < 0) return ret;
- if (timeout.expired()) {
- ret = -1;
- do_wait_and_fire_events(0, [current, &ret](thread* th) {
- if (th == current)
- ret = 0;
- else
- thread_interrupt(th, EOK);
- });
- if (ret <0) {
- enqueue(fd, ev, EV_DELETE, 0, current, true);
- errno = ETIMEDOUT;
- }
- return ret;
- }
  ret = thread_usleep(timeout);
  ERRNO err;
  if (ret == -1 && err.no == EOK) {
@@ -152,8 +138,13 @@ class KQueue : public MasterEventEngine, public CascadingEventEngine, public Res
  }
 
  int cancel_wait() override {
- enqueue(_kq, EVFILT_USER, EV_ONESHOT, NOTE_TRIGGER, nullptr, true);
- return 0;
+ // cannot call `enqueue` directly since it will be called from another vCPU.
+ // directly use kqueue to submit event, which is safe.
+ // as same as `enqueue(_kq, EVFILT_USER, EV_ONESHOT, NOTE_TRIGGER, nullptr, true)`
+ struct kevent entry;
+ EV_SET(&entry, _kq, EVFILT_USER, EV_ONESHOT, NOTE_TRIGGER, 0, nullptr);
+ struct timespec tm{0, 0};
+ return kevent(_kq, _events, _n, nullptr, 0, &tm);
  }
 
  // This vector is used to filter invalid add/rm_interest requests which may affect kevent's