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SubjectRe: [PATCH v3 rcu 08/11] arch/s390: Add ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option
On Thu, Oct 20, 2022 at 07:16:44AM +0200, Christian Borntraeger wrote:
>
>
> Am 20.10.22 um 00:58 schrieb Paul E. McKenney:
> > The s390 architecture uses either a cmpxchg loop (old systems)
> > or the laa add-to-memory instruction (new systems) to implement
> > this_cpu_add(), both of which are NMI safe. This means that the old
> > and more-efficient srcu_read_lock() may be used in NMI context, without
> > the need for srcu_read_lock_nmisafe(). Therefore, add the new Kconfig
> > option ARCH_HAS_NMI_SAFE_THIS_CPU_OPS to arch/arm64/Kconfig, which will
> s390 ?
> > cause NEED_SRCU_NMI_SAFE to be deselected, thus preserving the current
> > srcu_read_lock() behavior.
> >
> > Link: https://lore.kernel.org/all/20220910221947.171557773@linutronix.de/
> >
> > Suggested-by: Neeraj Upadhyay <quic_neeraju@quicinc.com>
> > Suggested-by: Frederic Weisbecker <frederic@kernel.org>
> > Suggested-by: Boqun Feng <boqun.feng@gmail.com>
> > Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
...
> > ---
> > arch/s390/Kconfig | 1 +
> > 1 file changed, 1 insertion(+)

Not sure what Christian was trying to say with his empty reply :)
In any case:
Acked-by: Heiko Carstens <hca@linux.ibm.com>

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