On Thu, 16 Apr 2020 14:53:12 -0400
Joel Fernandes <joel@xxxxxxxxxxxxxxxxx> wrote:
> > static inline this_cpu_spin_lock_irqsave(struct spinlock __per_cpu *lock)
> > {
> > migrate_disable();
> > spin_lock_irqsave(this_cpu_ptr(lock));
> > migrate_enable();
> > }
>
> Here we want to grab the pointer of a per-CPU structure for the local CPU,
> and then grab its lock at the same time without getting migrated, so at least
> for this code the above API, it may not fit properly but perhaps for other
> code it may.
this_cpu_spin_lock_irqsave(&krc.lock);
krcp = this_cpu_ptr(&krc);
Note, spin_lock() disables migration, even on PREEMPT_RT.
-- Steve
