On Fri, 2013-09-20 at 11:26 -0500, Frederic Weisbecker wrote: > Looks good to me. > > Now just for clarity, what do we then do with inline sofirq executions: on > local_bh_enable() > for example, or explicit calls to do_softirq() other than irq exit?
We cannot make the irq stack larger than the normal stacks on ppc due to how we get to the thread info (by masking low bits of the stack pointer), however our stacks are pretty big too (16k) so it might be ok to run the softirqs on the irq stack, it's just a matter of us doing the switch before do_IRQ rather than later when calling the handlers. I think we basically copied what x86 originally did, but we can definitely change that. > Should we keep the current switch to a different softirq stack? If we have a > generic irq stack > (used for both hard and soft) that is big enough, perhaps we can also switch > to this > generic irq stack for inline softirqs executions? After all there is no much > point in keeping > a separate stack for that: this result in cache misses if the inline softirq > is interrupted by > a hardirq, also inlined softirqs can't happen in hardirq, so there should be > no much risk of overruns. > > Or am I missing other things? Originally IRQs could nest so we really wanted separate stacks, especially since softirq is where network processing happens and that can go fairly deep. But that's not the case anymore so I suppose it makes some sense... Ben. > > > > Thanks, > > > > tglx > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
