Messages in this thread | | | Date | Wed, 2 Dec 2015 11:56:33 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH 2/7] nohz: New tick dependency mask |
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On Tue, Dec 01, 2015 at 11:20:28PM +0100, Frederic Weisbecker wrote: > > > + prev = fetch_or(dep, BIT_MASK(bit)); > > > + if (!prev) { > > > + /* > > > + * We need the IPIs to be sent from sane process context. > > > > Why ? > > Because posix timers code is all called with interrupts disabled and we can't > send IPIs then. > > > > > > + * The posix cpu timers are always set with irqs disabled. > > > + */ > > > + schedule_work(&kick_all_work); > > > + } > > > +} > > > + > > > +/* > > > + * Set a global tick dependency. Lets do the wide IPI kick asynchronously > > > + * for callers with irqs disabled. > > > > This seems to suggest you can call this with IRQs disabled > > Ah right, that's a misleading comment. We need to use the _delayed() version > when interrupts are disabled.
Why can't you use tick_nohz_full_kick_cpu() for all that, which is usable from IRQ context and avoid all that delayed muck?
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