* Jason Wang <[email protected]> wrote:
> Polling could be done by either rx busy loop in process
> context or NAPI in softirq. [...]
Note that this shows another reason why it's a bad idea to
query nr_running directly: depending on the softirq processing
method, a softirq might run:
- directly in process context
- in an idle thread's context
- or in a ksoftirqd context.
'nr_running' will have different values in these cases, causing
assymetries in busy-poll handling!
Another class of assymetry is when there are other softirq bits
pending, beyond NET_RX (or NET_TX): a nr_running check misses
them.
The solution I outlined in the previous mail (using a
sched_expected_runtime() method) would be able to avoid most of
these artifacts.
Thanks,
Ingo
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