Messages in this thread | | | Date | Mon, 23 Mar 2020 17:31:05 +0100 | From | Peter Zijlstra <> | Subject | Re: [RFC PATCH 1/3] lockdep/irq: Be more strict about IRQ-threadable code end |
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On Mon, Mar 23, 2020 at 04:30:40PM +0100, Frederic Weisbecker wrote: > On Mon, Mar 23, 2020 at 02:53:20PM +0100, Peter Zijlstra wrote: > > On Mon, Mar 23, 2020 at 04:32:05AM +0100, Frederic Weisbecker wrote: > > > --- a/kernel/irq/handle.c > > > +++ b/kernel/irq/handle.c > > > @@ -144,18 +144,24 @@ irqreturn_t __handle_irq_event_percpu(struct irq_desc *desc, unsigned int *flags > > > > > > for_each_action_of_desc(desc, action) { > > > irqreturn_t res; > > > + bool threadable; > > > > > > /* > > > * If this IRQ would be threaded under force_irqthreads, mark it so. > > > */ > > > - if (irq_settings_can_thread(desc) && > > > - !(action->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))) > > > + threadable = (irq_settings_can_thread(desc) && > > > + !(action->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))); > > > + > > > + if (threadable) > > > trace_hardirq_threaded(); > > > > > > trace_irq_handler_entry(irq, action); > > > res = action->handler(irq, action->dev_id); > > > trace_irq_handler_exit(irq, action, res); > > > > > > + if (threadable) > > > + trace_hardirq_unthreaded(); > > > > AFAICT this doesn't work for nested IRQ handlers. > > So current->hardirq_threaded should be a counter perhaps?
Yeah, see how the old code used the hardirq_context counter for exactly that. Also note how the old code was actually cheaper than this (minimally, but still).
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