From: Eric Dumazet <eduma...@google.com> Date: Fri, 21 Sep 2018 15:27:37 -0700
> As diagnosed by Song Liu, ndo_poll_controller() can > be very dangerous on loaded hosts, since the cpu > calling ndo_poll_controller() might steal all NAPI > contexts (for all RX/TX queues of the NIC). > > This capture, showing one ksoftirqd eating all cycles > can last for unlimited amount of time, since one > cpu is generally not able to drain all the queues under load. > > It seems that all networking drivers that do use NAPI > for their TX completions, should not provide a ndo_poll_controller() : > > Most NAPI drivers have netpoll support already handled > in core networking stack, since netpoll_poll_dev() > uses poll_napi(dev) to iterate through registered > NAPI contexts for a device. > > This patch series take care of the first round, we will > handle other drivers in future rounds. Series applied, thanks Eric.
