> On Sep 20, 2018, at 4:49 PM, Eric Dumazet <eric.dumazet@xxxxxxxxx> wrote: > > > > On 09/20/2018 04:43 PM, Song Liu wrote: >> > >> I tried to totally skip ndo_poll_controller() here. It did avoid hitting >> the issue. However, netpoll will drop (fail to send) more packets. >> > > Why is it failing ? > > If you are under high memory pressure, then maybe if you absolutely want memory to send > netpoll packets, you want to grab all NAPI contexts as a way to prevent other cpus > from feeding incoming packets to the host and add more memory pressure ;) > I did the test with Eric's latest patch (and disable ndo_poll_controller in driver). The result didn't show significant increase in drop packets. I guess packet drops in my earlier test was caused by some other changes I mixed there. So I think this patch does fix the issue. Thanks Eric! For ixgbe, I think we need to check napi_complete_done() return value anyway. Otherwise, the driver will enable IRQ in polling mode. Song
