Re: [PATCH v7 01/11] timekeeping: move multigrain timestamp floor handling into timekeeper

John Stultz
2024-09-13T19:17:41Z

On Fri, Sep 13, 2024 at 12:06 PM Jeff Layton <jlayton@kernel.org> wrote:
> On Fri, 2024-09-13 at 11:59 -0700, John Stultz wrote:
> > > +/**
> > > + * ktime_get_real_ts64_mg - attempt to update floor value and return result
> > > + * @ts: pointer to the timespec to be set
> > > + * @cookie: opaque cookie from earlier call to ktime_get_coarse_real_ts64_mg()
> > > + *
> > > + * Get a current monotonic fine-grained time value and attempt to swap
> > > + * it into the floor using @cookie as the "old" value. @ts will be
> > > + * filled with the resulting floor value, regardless of the outcome of
> > > + * the swap.
> >
> > I'd add more detail here to clarify that this can return a coarse
> > floor value if the cookie is stale.
> >
>
> Sure, or I can just drop the cookie, if that's better.

That seems like the simpler approach, but I don't have a sense of the
actual performance impact, so I'll leave that decision to you.

thanks
-john