[dpdk-dev] [PATCH v7 1/5] eal: add new definitions for wait scheme

[Ananyev, Konstantin]

> 
> diff --git a/lib/eal/include/generic/rte_pause.h b/lib/eal/include/generic/rte_pause.h
> index 668ee4a184..d0c5b5a415 100644
> --- a/lib/eal/include/generic/rte_pause.h
> +++ b/lib/eal/include/generic/rte_pause.h
> @@ -111,6 +111,34 @@ rte_wait_until_equal_64(volatile uint64_t *addr, uint64_t expected,
>  	while (__atomic_load_n(addr, memorder) != expected)
>  		rte_pause();
>  }
> +
> +/*
> + * Wait until *addr breaks the condition, with a relaxed memory
> + * ordering model meaning the loads around this API can be reordered.
> + *
> + * @param addr
> + *  A pointer to the memory location.
> + * @param mask
> + *  A mask of value bits in interest.
> + * @param cond
> + *  A symbol representing the condition.
> + * @param expected
> + *  An expected value to be in the memory location.
> + * @param memorder
> + *  Two different memory orders that can be specified:
> + *  __ATOMIC_ACQUIRE and __ATOMIC_RELAXED. These map to
> + *  C++11 memory orders with the same names, see the C++11 standard or
> + *  the GCC wiki on atomic synchronization for detailed definition.
> + */
> +#define rte_wait_event(addr, mask, cond, expected, memorder)                       \
> +do {                                                                               \
> +	RTE_BUILD_BUG_ON(!__builtin_constant_p(memorder));                         \
> +	RTE_BUILD_BUG_ON(memorder != __ATOMIC_ACQUIRE &&                           \
> +				memorder != __ATOMIC_RELAXED);                     \
> +	typeof(*(addr)) expected_value = (expected);                               \
> +	while ((__atomic_load_n((addr), (memorder)) & (mask)) cond expected_value) \
> +		rte_pause();                                                       \
> +} while (0)
>  #endif
> 
>  #endif /* _RTE_PAUSE_H_ */
> --

From generic/x86 perspective:
Acked-by: Konstantin Ananyev <konstantin.ananyev at intel.com>

> 2.25.1