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

[Peter Zijlstra]

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