On Wed, 24 Feb 2021 16:44:55 -0800 Wei Wang wrote:

On Wed, Feb 24, 2021 at 4:33 PM Jakub Kicinski [off-list ref] wrote:

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On Wed, 24 Feb 2021 16:16:58 -0800 Wei Wang wrote:  

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On Wed, Feb 24, 2021 at 4:11 PM Alexander Duyck [off-list ref] wrote:  

 [...]  

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Please help hold on to the patch for now. I think Martin is still
seeing issues on his setup even with this patch applied. I have not
yet figured out why. But I think we should not merge this patch until
the issue is cleared. Will update this thread with progress.  

If I'm looking right __busy_poll_stop() is only called if the last
napi poll used to re-enable IRQs consumed full budget. You need to
clear your new bit in busy_poll_stop(), not in __busy_poll_stop().
That will fix the case when hand off back to the normal poller (sirq,
or thread) happens without going thru __napi_schedule().  

If the budget is not fully consumed, napi_complete_done() should have
been called by the driver which will clear SCHED_BUSY_POLL bit.

Ah, right.