David Miller wrote:
From: Stephen Hemminger <[EMAIL PROTECTED]>
Date: Wed, 6 Dec 2006 16:58:35 -0800
The more robust way would be to stop the queue (like flow control)
and return busy. You would need a timer though to handle the case
where some disk i/o stole all the mappings and then network device flow
blocked.
You need some kind of fairness, yes, that's why I suggested a
callback. When your DMA allocation fails, you get into the rear of
the FIFO, when a free occurs, we callback starting from the head of
the FIFO. You don't get removed from the FIFO unless at least one of
your DMA allocation retries succeed.
While tossing a TCP|UDP|SCTP|etc packet could be plusungood, especially
if the IOMMU fills frequently (for some suitable definiton of
frequently), is it really worth the effort to save say an ACK?
rick jones
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