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

From: Shuah Khan
Date: Tue Sep 04 2012 - 19:24:08 EST


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@xxxxxx>
> ---
> 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);


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