On Fri, 31 Aug 2012 18:55:59 -0600
Shuah Khan <shuah.k...@hp.com> wrote:
> Add kernel error message to track iotlb overflow buffer triggers to understand
> how often the overflow buffer gets used.
>
> Signed-off-by: Shuah Khan <shuah.k...@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);
hm. I would view this as a developer-only debugging thing which
shouldn't be present in production code. Plus there's a potential that
some poor person will have his logs flooded with this message.
A more typical way of handling this would be to increment a stats
counter, accessible in procfs or debugfs.
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