net: less interrupt masking in NAPI
net_rx_action() can mask irqs a single time to transfert sd->poll_list into a private list, for a very short duration. Then, napi_complete() can avoid masking irqs again, and net_rx_action() only needs to mask irq again in slow path. This patch removes 2 couples of irq mask/unmask per typical NAPI run, more if multiple napi were triggered. Note this also allows to give control back to caller (do_softirq()) more often, so that other softirq handlers can be called a bit earlier, or ksoftirqd can be wakeup earlier under pressure. This was developed while testing an alternative to RX interrupt mitigation to reduce latencies while keeping or improving GRO aggregation on fast NIC. Idea is to test napi->gro_list at the end of a napi->poll() and reschedule one NAPI poll, but after servicing a full round of softirqs (timers, TX, rcu, ...). This will be allowed only if softirq is currently serviced by idle task or ksoftirqd, and resched not needed. Signed-off-by:Eric Dumazet <edumazet@google.com> Cc: Willem de Bruijn <willemb@google.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
parent
4cdb1e2e
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