Re: [Qemu-devel] [PATCH 15/17] main-loop: use aio_notify for qemu_notify_event

[Anthony Liguori <anthony@codemonkey.ws>]

Paolo Bonzini <pbonzini@redhat.com> writes:

> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  main-loop.c | 106 +++++-------------------------------------------------------
>  1 file modificato, 8 inserzioni(+), 98 rimozioni(-)

diffstats like this are always a good sign :-)

Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>

Regards,

Anthony Liguori

>
> diff --git a/main-loop.c b/main-loop.c
> index 209f699..978050a 100644
> --- a/main-loop.c
> +++ b/main-loop.c
> @@ -32,70 +32,6 @@
>  
>  #include "compatfd.h"
>  
> -static int io_thread_fd = -1;
> -
> -void qemu_notify_event(void)
> -{
> -    /* Write 8 bytes to be compatible with eventfd.  */
> -    static const uint64_t val = 1;
> -    ssize_t ret;
> -
> -    if (io_thread_fd == -1) {
> -        return;
> -    }
> -    do {
> -        ret = write(io_thread_fd, &val, sizeof(val));
> -    } while (ret < 0 && errno == EINTR);
> -
> -    /* EAGAIN is fine, a read must be pending.  */
> -    if (ret < 0 && errno != EAGAIN) {
> -        fprintf(stderr, "qemu_notify_event: write() failed: %s\n",
> -                strerror(errno));
> -        exit(1);
> -    }
> -}
> -
> -static void qemu_event_read(void *opaque)
> -{
> -    int fd = (intptr_t)opaque;
> -    ssize_t len;
> -    char buffer[512];
> -
> -    /* Drain the notify pipe.  For eventfd, only 8 bytes will be read.  */
> -    do {
> -        len = read(fd, buffer, sizeof(buffer));
> -    } while ((len == -1 && errno == EINTR) || len == sizeof(buffer));
> -}
> -
> -static int qemu_event_init(void)
> -{
> -    int err;
> -    int fds[2];
> -
> -    err = qemu_eventfd(fds);
> -    if (err == -1) {
> -        return -errno;
> -    }
> -    err = fcntl_setfl(fds[0], O_NONBLOCK);
> -    if (err < 0) {
> -        goto fail;
> -    }
> -    err = fcntl_setfl(fds[1], O_NONBLOCK);
> -    if (err < 0) {
> -        goto fail;
> -    }
> -    qemu_set_fd_handler2(fds[0], NULL, qemu_event_read, NULL,
> -                         (void *)(intptr_t)fds[0]);
> -
> -    io_thread_fd = fds[1];
> -    return 0;
> -
> -fail:
> -    close(fds[0]);
> -    close(fds[1]);
> -    return err;
> -}
> -
>  /* If we have signalfd, we mask out the signals we want to handle and then
>   * use signalfd to listen for them.  We rely on whatever the current signal
>   * handler is to dispatch the signals when we receive them.
> @@ -165,43 +101,22 @@ static int qemu_signal_init(void)
>  
>  #else /* _WIN32 */
>  
> -static HANDLE qemu_event_handle = NULL;
> -
> -static void dummy_event_handler(void *opaque)
> -{
> -}
> -
> -static int qemu_event_init(void)
> +static int qemu_signal_init(void)
>  {
> -    qemu_event_handle = CreateEvent(NULL, FALSE, FALSE, NULL);
> -    if (!qemu_event_handle) {
> -        fprintf(stderr, "Failed CreateEvent: %ld\n", GetLastError());
> -        return -1;
> -    }
> -    qemu_add_wait_object(qemu_event_handle, dummy_event_handler, NULL);
>      return 0;
>  }
> +#endif
> +
> +static AioContext *qemu_aio_context;
>  
>  void qemu_notify_event(void)
>  {
> -    if (!qemu_event_handle) {
> +    if (!qemu_aio_context) {
>          return;
>      }
> -    if (!SetEvent(qemu_event_handle)) {
> -        fprintf(stderr, "qemu_notify_event: SetEvent failed: %ld\n",
> -                GetLastError());
> -        exit(1);
> -    }
> +    aio_notify(qemu_aio_context);
>  }
>  
> -static int qemu_signal_init(void)
> -{
> -    return 0;
> -}
> -#endif
> -
> -static AioContext *qemu_aio_context;
> -
>  int main_loop_init(void)
>  {
>      int ret;
> @@ -213,12 +128,6 @@ int main_loop_init(void)
>          return ret;
>      }
>  
> -    /* Note eventfd must be drained before signalfd handlers run */
> -    ret = qemu_event_init();
> -    if (ret) {
> -        return ret;
> -    }
> -
>      qemu_aio_context = aio_context_new();
>      src = aio_get_g_source(qemu_aio_context);
>      g_source_attach(src, NULL);
> @@ -408,7 +317,8 @@ void qemu_del_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
>  
>  void qemu_fd_register(int fd)
>  {
> -    WSAEventSelect(fd, qemu_event_handle, FD_READ | FD_ACCEPT | FD_CLOSE |
> +    WSAEventSelect(fd, event_notifier_get_handle(&qemu_aio_context->notifier),
> +                   FD_READ | FD_ACCEPT | FD_CLOSE |
>                     FD_CONNECT | FD_WRITE | FD_OOB);
>  }
>  
> -- 
> 1.7.12