Re: [PATCH 2/2] dmaengine: ioat: Decreasing allocation chunk size 2M -> 512K

[Dave Jiang]

On 4/2/2020 2:27 AM, leonid.ravich@xxxxxxxx wrote:
> From: Leonid Ravich <Leonid.Ravich@xxxxxxx>
>
> current IOAT driver using big (2MB) allocations chunk for its descriptors
> therefore each ioat dma engine need 2 such chunks
> (64k entres in ring  each entry 64B = 4MB)
> requiring 2 * 2M * dmaengine contiguies memory chunk
> might fail due to memory fragmention.
>
> so we decresging chunk size and using more chunks.

decreasing

> Signed-off-by: Leonid Ravich <Leonid.Ravich@xxxxxxx>

Acked-by: Dave Jiang <dave.jiang@xxxxxxxxx> if the two patches have been 
tested on hw.

> ---
>   drivers/dma/ioat/dma.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/dma/ioat/dma.h b/drivers/dma/ioat/dma.h
> index 535aba9..e9757bc 100644
> --- a/drivers/dma/ioat/dma.h
> +++ b/drivers/dma/ioat/dma.h
> @@ -83,7 +83,7 @@ struct ioatdma_device {
>   
>   #define IOAT_MAX_ORDER 16
>   #define IOAT_MAX_DESCS (1 << IOAT_MAX_ORDER)
> -#define IOAT_CHUNK_SIZE (SZ_2M)
> +#define IOAT_CHUNK_SIZE (SZ_512K)
>   #define IOAT_DESCS_PER_CHUNK (IOAT_CHUNK_SIZE/IOAT_DESC_SZ)
>   
>   struct ioat_descs {