Re: [PATCH 1/2] [RFC] Fix clock_was_set so it is safe to call from atomic

Thomas Gleixner
2012-07-02T08:53:15Z

On Sun, 1 Jul 2012, John Stultz wrote:

> NOTE:This is a prerequisite patch that's required to
> address the widely observed leap-second related futex/hrtimer
> issues.
>
> Currently clock_was_set() is unsafe to be called from atomic
> context, as it calls on_each_cpu(). This causes problems when
> we need to adjust the time from update_wall_time().
>
> To fix this, introduce a work_struct so if we're in_atomic,
> we can schedule work to do the necessary update after we're
> out of the atomic section.

Shouldn't we queue a timer_list timer with expiry time jiffies + 0
instead. We can call on_each_cpu() from softirq context. And that
ensures that the update happens right away, while a scheduled work
might be delayed arbitrary long.

Thanks,

tglx