Re: [dpdk-dev] [PATCH v2 1/8] eal: introduce DMA memory barriers

[Jianbo Liu <jianbo.liu@arm.com>]

The 01/15/2018 17:10, Yongseok Koh wrote:
> This commit introduces rte_dma_wmb() and rte_dma_rmb(), in order to
> guarantee the ordering of coherent shared memory between the CPU and a DMA
> capable device.
>
> Signed-off-by: Yongseok Koh <yskoh@mellanox.com>

Acked-by: Jianbo Liu <jianbo.liu@arm.com>

> ---
>  lib/librte_eal/common/include/generic/rte_atomic.h | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
>
> diff --git a/lib/librte_eal/common/include/generic/rte_atomic.h b/lib/librte_eal/common/include/generic/rte_atomic.h
> index 16af5ca57..2e0503ce6 100644
> --- a/lib/librte_eal/common/include/generic/rte_atomic.h
> +++ b/lib/librte_eal/common/include/generic/rte_atomic.h
> @@ -98,6 +98,24 @@ static inline void rte_io_wmb(void);
>   */
>  static inline void rte_io_rmb(void);
>
> +/**
> + * Write memory barrier for coherent memory between lcore and IO device
> + *
> + * Guarantees that the STORE operations on coherent memory that
> + * precede the rte_dma_wmb() call are visible to I/O device before the
> + * STORE operations that follow it.
> + */
> +static inline void rte_dma_wmb(void);
> +
> +/**
> + * Read memory barrier for coherent memory between lcore and IO device
> + *
> + * Guarantees that the LOAD operations on coherent memory updated by
> + * IO device that precede the rte_dma_rmb() call are visible to CPU
> + * before the LOAD operations that follow it.
> + */
> +static inline void rte_dma_rmb(void);
> +
>  #endif /* __DOXYGEN__ */
>
>  /**
> --
> 2.11.0
>

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