On Thu, 17 Jun 2021 08:50:53 -0300
Adhemerval Zanella <adhemerval.zanella@linaro.org> wrote:

> It breaks the usage case of live migration like CRIU or similar.
> The performance drawback is it would require an extra syscall
> on older kernels without 64-bit time support.
> 
> Checked on i686-linux-gnu on a 4.15 kernel and on a 5.11 kernel
> (with and without --enable-kernel=5.1) and on x86_64-linux-gnu.
> ---
>  sysdeps/unix/sysv/linux/clock_getres.c | 16 +++++-----------
>  1 file changed, 5 insertions(+), 11 deletions(-)
> 
> diff --git a/sysdeps/unix/sysv/linux/clock_getres.c
> b/sysdeps/unix/sysv/linux/clock_getres.c index a9edec93e6..83f0593074
> 100644 --- a/sysdeps/unix/sysv/linux/clock_getres.c
> +++ b/sysdeps/unix/sysv/linux/clock_getres.c
> @@ -21,7 +21,6 @@
>  #include <time.h>
>  
>  #include <sysdep-vdso.h>
> -#include <time64-support.h>
>  #include <shlib-compat.h>
>  #include <kernel-features.h>
>  
> @@ -34,19 +33,14 @@ __clock_getres64 (clockid_t clock_id, struct
> __timespec64 *res) #ifndef __NR_clock_getres_time64
>  # define __NR_clock_getres_time64 __NR_clock_getres
>  #endif
> -  if (supports_time64 ())
> -    {
> +
>  #ifdef HAVE_CLOCK_GETRES64_VSYSCALL
> -      r = INLINE_VSYSCALL (clock_getres_time64, 2, clock_id, res);
> +  r = INLINE_VSYSCALL (clock_getres_time64, 2, clock_id, res);
>  #else
> -      r = INLINE_SYSCALL_CALL (clock_getres_time64, clock_id, res);
> +  r = INLINE_SYSCALL_CALL (clock_getres_time64, clock_id, res);
>  #endif
> -
> -      if (r == 0 || errno != ENOSYS)
> -	return r;
> -
> -      mark_time64_unsupported ();
> -    }
> +  if (r == 0 || errno != ENOSYS)
> +    return r;
>  
>  #ifndef __ASSUME_TIME64_SYSCALLS
>    /* Fallback code that uses 32-bit support.  */

Reviewed-by: Lukasz Majewski <lukma@denx.de>


Best regards,

Lukasz Majewski

--

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