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Re: Mbufs stored in RX queues
>It looks to me that holding a number of mbufs in the rxq is useless
>since anyway we will fail to keep the incoming packet if we can't
>allocate a new mbuf when the packet arrives.
There are systems where multiple packets can arrive even before
the interrupt routine is entered.
>Could anyone please help me see when this could be useful? From my
>perspective, it looks like passing up a freshly allocated mbuf would
>make us spend exactly the same amount of time in the interrupt handler,
>waste less memory, and simplify the code.
The mbuf needs to exist before the interrupt is requested. If you want to
pass up a new mbuf you need to copy the data to that new mbuf first. Some
drivers even do this, but only for small packets that fit into a single
Michael van Elst
"A potential Snark may lurk in every tree."
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