Re: [patch 2/2] introduce vdso on s390

From: Bastian Blank
Date: Fri Oct 17 2008 - 11:34:49 EST


On Wed, Oct 15, 2008 at 07:45:08PM +0200, Martin Schwidefsky wrote:
> +void update_vsyscall(struct timespec *wall_time, struct clocksource *clock)
> +{
> + if (clock != &clocksource_tod)
> + return;
> +
> + /* Make userspace gettimeofday spin until we're done. */
> + ++vdso_data->tb_update_count;
> + smp_mb();
> + vdso_data->xtime_tod_stamp = clock->cycle_last;
> + vdso_data->xtime_clock_sec = xtime.tv_sec;
> + vdso_data->xtime_clock_nsec = xtime.tv_nsec;
> + vdso_data->wtom_clock_sec = wall_to_monotonic.tv_sec;
> + vdso_data->wtom_clock_nsec = wall_to_monotonic.tv_nsec;
> + smp_wmb();

Different barriers?

> + ++(vdso_data->tb_update_count);

Why ++(...)?

Bastian

--
Either one of us, by himself, is expendable. Both of us are not.
-- Kirk, "The Devil in the Dark", stardate 3196.1
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/