Re: [patch] timer/hrtimer: take per cpu locks in sane order

Ingo Molnar
2007-03-02T13:12:35Z

* Heiko Carstens <heiko.carstens@de.ibm.com> wrote:

> - spin_lock(&new_base->lock);
> - spin_lock(&old_base->lock);
> + /*
> + * If we take a lock from a different cpu, make sure we have always
> + * the same locking order. That is the lock that belongs to the cpu
> + * with the lowest number is taken first.
> + */
> + lock1 = smp_processor_id() < cpu ? &new_base->lock : &old_base->lock;
> + lock2 = smp_processor_id() < cpu ? &old_base->lock : &new_base->lock;
> + spin_lock(lock1);
> + spin_lock(lock2);

looks good to me. Wouldnt this be cleaner via double_lock_timer() -
similar to how double_rq_lock() works in kernel/sched.c - instead of
open-coding it?

Ingo