Re: [PATCH] swiotlb: add kernel error message to track iobtlb overflow buffer usage

[Shuah Khan <shuah.khan@hp.com>]

On Fri, 2012-08-31 at 18:55 -0600, Shuah Khan wrote:
> Add kernel error message to track iotlb overflow buffer triggers to understand
> how often the overflow buffer gets used.

Does this change look reasonable? My intent is to be able to assess how
often the overflow buffer usage gets triggered.

-- Shuah
> 
> Signed-off-by: Shuah Khan <shuah.khan@hp.com>
> ---
>  lib/swiotlb.c |    1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/lib/swiotlb.c b/lib/swiotlb.c
> index 45bc1f8..597d7b9 100644
> --- a/lib/swiotlb.c
> +++ b/lib/swiotlb.c
> @@ -682,6 +682,7 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
>  	if (!map) {
>  		swiotlb_full(dev, size, dir, 1);
>  		map = io_tlb_overflow_buffer;
> +		dev_err(dev, "SWIOTLB is full. Mapping overflow buffer.\n");
>  	}
>  
>  	dev_addr = swiotlb_virt_to_bus(dev, map);