Messages in this thread | | | Date | Tue, 4 Sep 2012 16:28:04 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] swiotlb: add kernel error message to track iobtlb overflow buffer usage |
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On Fri, 31 Aug 2012 18:55:59 -0600 Shuah Khan <shuah.khan@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.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);
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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