[dpdk-dev] [PATCH v6 3/4] eal: use wait event scheme for mcslock

[Mattias Rönnblom]

On 2021-10-27 10:10, Feifei Wang wrote:
> Instead of polling for mcslock to be updated, use wait event scheme
> for this case.
>
> Signed-off-by: Feifei Wang <feifei.wang2 at arm.com>
> Reviewed-by: Ruifeng Wang <ruifeng.wang at arm.com>
> ---
>   lib/eal/include/generic/rte_mcslock.h | 9 +++++++--
>   1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/lib/eal/include/generic/rte_mcslock.h b/lib/eal/include/generic/rte_mcslock.h
> index 34f33c64a5..806a2b2c7e 100644
> --- a/lib/eal/include/generic/rte_mcslock.h
> +++ b/lib/eal/include/generic/rte_mcslock.h
> @@ -116,8 +116,13 @@ rte_mcslock_unlock(rte_mcslock_t **msl, rte_mcslock_t *me)
>   		/* More nodes added to the queue by other CPUs.
>   		 * Wait until the next pointer is set.
>   		 */
> -		while (__atomic_load_n(&me->next, __ATOMIC_RELAXED) == NULL)
> -			rte_pause();
> +#ifdef RTE_ARCH_32
> +		rte_wait_event((uint32_t *)&me->next, UINT32_MAX, ==, 0,
> +				__ATOMIC_RELAXED);
> +#else
> +		rte_wait_event((uint64_t *)&me->next, UINT64_MAX, ==, 0,
> +				__ATOMIC_RELAXED);
> +#endif
>   	}
>   
>   	/* Pass lock to next waiter. */

You could do something like

rte_wait_event((uintptr_t *)&me->next, UINTPTR_MAX, ==, 0, __ATOMIC_RELAXED);

and avoid the #ifdef.