Re: [PATCH 1/8] locking: Introduce local_lock()

Peter Zijlstra
2020-05-20T12:05:31Z

On Tue, May 19, 2020 at 10:19:05PM +0200, Sebastian Andrzej Siewior wrote:
> +/**
> + * DEFINE_LOCAL_LOCK - Define and initialize a per CPU local lock
> + * @lock: Name of the lock instance
> + */
> +#define DEFINE_LOCAL_LOCK(lvar) \
> + DEFINE_PER_CPU(struct local_lock, lvar) = { INIT_LOCAL_LOCK(lvar) }
> +
> +/**
> + * DECLARE_LOCAL_LOCK - Declare a defined per CPU local lock
> + * @lock: Name of the lock instance
> + */
> +#define DECLARE_LOCAL_LOCK(lvar) \
> + DECLARE_PER_CPU(struct local_lock, lvar)

So I think I'm going to argue having these is a mistake. The local_lock
should be put in a percpu structure along with the data it actually
protects.

> +#ifdef CONFIG_DEBUG_LOCK_ALLOC
> +# define LL_DEP_MAP_INIT(lockname) .dep_map = { .name = #lockname }

That wants to be:

.dep_map = {
.name = #lockname,
.wait_type_inner = LD_WAIT_SPIN,
}

> +#else
> +# define LL_DEP_MAP_INIT(lockname)
> +#endif