[PATCH v2 02/14] linux: Add ppoll time64 optimization

Alistair Francis alistair23@gmail.com
Thu Sep 10 19:21:01 GMT 2020


On Tue, Sep 8, 2020 at 7:58 AM Adhemerval Zanella via Libc-alpha
<libc-alpha@sourceware.org> wrote:
>
> It avoid continuing issue the __NR_ppoll_time64 syscall once the kernel
> advertise it does not support it.
>
> Checked on x86_64-linux-gnu and i686-linux-gnu (on 5.4 and on 4.15
> kernel).

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
>  sysdeps/unix/sysv/linux/ppoll.c | 18 +++++++++++++-----
>  1 file changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/sysdeps/unix/sysv/linux/ppoll.c b/sysdeps/unix/sysv/linux/ppoll.c
> index dd2167fc55..e68a153427 100644
> --- a/sysdeps/unix/sysv/linux/ppoll.c
> +++ b/sysdeps/unix/sysv/linux/ppoll.c
> @@ -22,6 +22,7 @@
>  #include <sys/poll.h>
>  #include <sysdep-cancel.h>
>  #include <kernel-features.h>
> +#include <time64-support.h>
>
>
>  int
> @@ -37,16 +38,23 @@ __ppoll64 (struct pollfd *fds, nfds_t nfds, const struct __timespec64 *timeout,
>        timeout = &tval;
>      }
>
> +  int ret;
> +
> +  if (supports_time64 ())
> +    {
>  #ifndef __NR_ppoll_time64
>  # define __NR_ppoll_time64 __NR_ppoll
>  #endif
> -  int ret = SYSCALL_CANCEL (ppoll_time64, fds, nfds, timeout, sigmask,
> -                            __NSIG_BYTES);
> +      ret = SYSCALL_CANCEL (ppoll_time64, fds, nfds, timeout, sigmask,
> +                           __NSIG_BYTES);
>
> -#ifndef __ASSUME_TIME64_SYSCALLS
> -  if (ret >= 0 || errno != ENOSYS)
> -    return ret;
> +      if (ret == 0 || errno != ENOSYS)
> +       return ret;
>
> +      mark_time64_unsupported ();
> +    }
> +
> +#ifndef __ASSUME_TIME64_SYSCALLS
>    struct timespec ts32;
>    if (timeout)
>      {
> --
> 2.25.1
>


More information about the Libc-alpha mailing list