Re: Relationship between Rx/Tx ring and Skbuff.

On Wed, 05 Aug 2020 11:34:52 -0700, Vasu M said:

quoted

it on a high level, when a packet is received in a NIC, DMA  moves the
packets from the NIC frame buffer into the RX ring buffer in the driver.

A

quoted

hardware interrupt is then raised and the top half moves the packet to

the

quoted

RX ring buffer.

Umm... I would expect the packet to be moved to the RX ring buffer exactly
once,
not twice...

I am sorry, yes, thats a mistake and it makes sense. If the DMA moves the
packet to the RX ring, the top half just acknowledges the interrupt and
schedules the softirq to drain the packets from RX. Subsequently, after the
packets go through sk_buff, they get queued in the socket recv buffer and
get to user space memory finally? I suppose I am only scratching the
surface leaving so many details.