On Thu, Jul 17, 2025 at 08:25:26AM -0400, Steven Rostedt wrote:
> On Wed, 16 Jul 2025 21:43:47 -0700
> "Paul E. McKenney" <[email protected]> wrote:
>
> > > +DEFINE_LOCK_GUARD_1(srcu_lite, struct srcu_struct,
> >
> > You need srcu_fast because srcu_lite is being removed. They are quite
> > similar, but srcu_fast is faster and is NMI-safe. (This last might or
> > might not matter here.)
> >
> > See https://lore.kernel.org/all/[email protected]/
> > for a srcu_fast_notrace, so something like this:
>
> Yeah, I already saw that patch.
>
> >
> > DEFINE_LOCK_GUARD_1(srcu_fast, struct srcu_struct,
> > _T->scp = srcu_read_lock_fast(_T->lock),
> > srcu_read_unlock_fast(_T->lock, _T->scp),
> > struct srcu_ctr __percpu *scp)
> >
> > Other than that, it looks plausible.
>
> Using srcu_lite or srcu_fast is an optimization here. And since I saw you
> adding the guard for srcu_fast in that other thread, I'll just use normal
> SRCU here for this series, and in the future we could convert it over to
> srcu_fast.
Works for me!
That said, "in the future" started in -next some time back and is slated
to start in mainline in the upcoming v6.17 merge window. SRCU-lite is
being removed from the kernel, and has been deprecated via checkpatch.pl.
So if there is some reason that you absolutely cannot immediately convert
to SRCU-fast, let's please discuss.
Thanx, Paul
