On Mon, 2009-03-02 at 14:57 -0800, Andrew Morton wrote: > On Mon, 02 Mar 2009 14:46:47 -0800 (PST) > David Miller <davem@xxxxxxxxxxxxx> wrote: > > > From: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> > > Date: Mon, 02 Mar 2009 23:19:31 +0100 > > > > > I state that every !IRQF_DISABLED usage is a bug, either due to broken > > > hardware or broken drivers. > > > > We'll send you the bill to have everyone's hardware > > replaced :-) > > yes, but with what? > > No matter how fast all our interrupt handlers are, running them with > local interrupts disabled has to worsen the worst-case interrupt > latency. > > I don't see how removing !IRQF_DISABLED improves the kernel - in fact > there's a latency argument for making !IRQF_DISABLED the default. On preempt-rt all we do in the hardirq path is mask the interrupt line and wake up a thread. That's the extreme end of low latency interrupts. Arguably there is a middle way that works for !-rt. However, striving to enable interrupts in all interrupt handlers is asking for stack overruns. Interrupt nesting just isn't really helpful. -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
