On Fri, 14 May 2021 12:17:19 +0200 Thomas Gleixner wrote: > The driver invokes napi_schedule() in several places from task > context. napi_schedule() raises the NET_RX softirq bit and relies on the > calling context to ensure that the softirq is handled. That's usually on > return from interrupt or on the outermost local_bh_enable(). > > But that's not the case here which causes the soft interrupt handling to be > delayed to the next interrupt or local_bh_enable(). If the task in which > context this is invoked is the last runnable task on a CPU and the CPU goes > idle before an interrupt arrives or a local_bh_disable/enable() pair > handles the pending soft interrupt then the NOHZ idle code emits the > following warning. > > NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #08!!! > > Prevent this by wrapping the napi_schedule() invocation from task context > into a local_bh_disable/enable() pair. I should have read through my inbox before replying :) I'd go for switching to raise_softirq_irqoff() in ____napi_schedule()... why not?
