diff --git a/src/unix/async.c b/src/unix/async.c index 0ff2669e..aef25f6b 100644 --- a/src/unix/async.c +++ b/src/unix/async.c @@ -38,6 +38,34 @@ #include #endif +#if UV__KQUEUE_EVFILT_USER +static uv_once_t kqueue_runtime_detection_guard = UV_ONCE_INIT; +static int kqueue_evfilt_user_support = 1; + + +static void uv__kqueue_runtime_detection(void) { + int kq; + struct kevent ev[2]; + struct timespec timeout = {0, 0}; + + /* Perform the runtime detection to ensure that kqueue with + * EVFILT_USER actually works. */ + kq = kqueue(); + EV_SET(ev, UV__KQUEUE_EVFILT_USER_IDENT, EVFILT_USER, + EV_ADD | EV_CLEAR, 0, 0, 0); + EV_SET(ev + 1, UV__KQUEUE_EVFILT_USER_IDENT, EVFILT_USER, + 0, NOTE_TRIGGER, 0, 0); + if (kevent(kq, ev, 2, ev, 1, &timeout) < 1 || + ev[0].filter != EVFILT_USER || + ev[0].ident != UV__KQUEUE_EVFILT_USER_IDENT || + ev[0].flags & EV_ERROR) + /* If we wind up here, we can assume that EVFILT_USER is defined but + * broken on the current system. */ + kqueue_evfilt_user_support = 0; + uv__close(kq); +} +#endif + static void uv__async_send(uv_loop_t* loop); static int uv__async_start(uv_loop_t* loop); static void uv__cpu_relax(void); @@ -139,7 +167,11 @@ static void uv__async_io(uv_loop_t* loop, uv__io_t* w, unsigned int events) { assert(w == &loop->async_io_watcher); +#if UV__KQUEUE_EVFILT_USER + for (;!kqueue_evfilt_user_support;) { +#else for (;;) { +#endif r = read(w->fd, buf, sizeof(buf)); if (r == sizeof(buf)) @@ -195,6 +227,17 @@ static void uv__async_send(uv_loop_t* loop) { len = sizeof(val); fd = loop->async_io_watcher.fd; /* eventfd */ } +#elif defined(UV__KQUEUE_EVFILT_USER) + struct kevent ev; + + if (kqueue_evfilt_user_support) { + fd = loop->async_io_watcher.fd; /* magic number for EVFILT_USER */ + EV_SET(&ev, fd, EVFILT_USER, 0, NOTE_TRIGGER, 0, 0); + r = kevent(loop->backend_fd, &ev, 1, NULL, 0, NULL); + if (r == 0) + return; + abort(); + } #endif do @@ -215,6 +258,9 @@ static void uv__async_send(uv_loop_t* loop) { static int uv__async_start(uv_loop_t* loop) { int pipefd[2]; int err; +#if UV__KQUEUE_EVFILT_USER + struct kevent ev; +#endif if (loop->async_io_watcher.fd != -1) return 0; @@ -226,6 +272,36 @@ static int uv__async_start(uv_loop_t* loop) { pipefd[0] = err; pipefd[1] = -1; +#elif UV__KQUEUE_EVFILT_USER + uv_once(&kqueue_runtime_detection_guard, uv__kqueue_runtime_detection); + if (kqueue_evfilt_user_support) { + /* In order not to break the generic pattern of I/O polling, a valid + * file descriptor is required to take up a room in loop->watchers, + * thus we create one for that, but this fd will not be actually used, + * it's just a placeholder and magic number which is going to be closed + * during the cleanup, as other FDs. */ + err = uv__open_cloexec("/dev/null", O_RDONLY); + if (err < 0) + return err; + + pipefd[0] = err; + pipefd[1] = -1; + + /* When using EVFILT_USER event to wake up the kqueue, this event must be + * registered beforehand. Otherwise, calling kevent() to issue an + * unregistered EVFILT_USER event will get an ENOENT. + * Since uv__async_send() may happen before uv__io_poll() with multi-threads, + * we can't defer this registration of EVFILT_USER event as we did for other + * events, but must perform it right away. */ + EV_SET(&ev, err, EVFILT_USER, EV_ADD | EV_CLEAR, 0, 0, 0); + err = kevent(loop->backend_fd, &ev, 1, NULL, 0, NULL); + if (err < 0) + return UV__ERR(errno); + } else { + err = uv__make_pipe(pipefd, UV_NONBLOCK_PIPE); + if (err < 0) + return err; + } #else err = uv__make_pipe(pipefd, UV_NONBLOCK_PIPE); if (err < 0) @@ -236,6 +312,13 @@ static int uv__async_start(uv_loop_t* loop) { uv__io_start(loop, &loop->async_io_watcher, POLLIN); loop->async_wfd = pipefd[1]; +#if UV__KQUEUE_EVFILT_USER + /* Prevent the EVFILT_USER event from being added to kqueue redundantly + * and mistakenly later in uv__io_poll(). */ + if (kqueue_evfilt_user_support) + loop->async_io_watcher.events = loop->async_io_watcher.pevents; +#endif + return 0; } diff --git a/src/unix/internal.h b/src/unix/internal.h index 8d586b0b..698caf17 100644 --- a/src/unix/internal.h +++ b/src/unix/internal.h @@ -35,6 +35,10 @@ #include #include #include +#if defined(__APPLE__) || defined(__DragonFly__) || \ + defined(__FreeBSD__) || defined(__NetBSD__) +#include +#endif #define uv__msan_unpoison(p, n) \ do { \ @@ -504,4 +508,22 @@ int uv__get_constrained_cpu(uv__cpu_constraint* constraint); #endif #endif +#if defined(EVFILT_USER) && defined(NOTE_TRIGGER) +/* EVFILT_USER is available since OS X 10.6, DragonFlyBSD 4.0, + * FreeBSD 8.1, and NetBSD 10.0. + * + * Note that even though EVFILT_USER is defined on the current system, + * it may still fail to work at runtime somehow. In that case, we fall + * back to pipe-based signaling. + */ +#define UV__KQUEUE_EVFILT_USER 1 +/* Magic number of identifier used for EVFILT_USER during runtime detection. + * There are no Google hits for this number when I create it. That way, + * people will be directed here if this number gets printed due to some + * kqueue error and they google for help. */ +#define UV__KQUEUE_EVFILT_USER_IDENT 0x1e7e7711 +#else +#define UV__KQUEUE_EVFILT_USER 0 +#endif + #endif /* UV_UNIX_INTERNAL_H_ */ diff --git a/src/unix/kqueue.c b/src/unix/kqueue.c index 66aa166f..876b7170 100644 --- a/src/unix/kqueue.c +++ b/src/unix/kqueue.c @@ -367,6 +367,17 @@ void uv__io_poll(uv_loop_t* loop, int timeout) { continue; } +#if UV__KQUEUE_EVFILT_USER + if (ev->filter == EVFILT_USER) { + w = &loop->async_io_watcher; + assert(fd == w->fd); + uv__metrics_update_idle_time(loop); + w->cb(loop, w, w->events); + nevents++; + continue; + } +#endif + if (ev->filter == EVFILT_VNODE) { assert(w->events == POLLIN); assert(w->pevents == POLLIN);