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Jakub Kicinski authored
Reading TX queue indexes from the device memory on each interrupt is expensive. It's doubly expensive with XDP running since we have two TX rings to check there. If the software indexes indicate that the TX queue is completely empty, however, we don't need to look at the device completion index at all. The queuing CPU is doing a wmb() before kicking the device TX so we should be safe to assume on the CPU handling the completions will never see old value of the software copy of the index. Signed-off-by:
Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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