On Fri, Sep 20, 2013 at 07:30:14PM +0200, Thomas Gleixner wrote: > On Fri, 20 Sep 2013, Frederic Weisbecker wrote: > > > 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? 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. > > We can use the same irqstack for this because from the irqstack point > of view, thats the same as if softirqs get executed from > irq_exit().
Ok, so I see that's what x86-64 is doing. But x86-32 seems to be using different stacks for hard and soft irqs for no much reasons (expept maybe to avoid overrun if the hardirq). And x86-32 only switches to hardirq stack for the handler. So probably we can use the same stack for the whole and extend it to before irq_enter() and after irq_exit(), like you suggested. BTW, we still want the 1st patch of my series I think, as it simply consolidate existing code. Using the same stack for hard and soft irqs is independant from that. If you're ok with it, would you agree to apply it? Thanks. -- 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/
