Re: [PATCH 2/2] irq: Cleanup context state transitions inirq_exit()

From: Thomas Gleixner
Date: Tue Feb 26 2013 - 07:15:22 EST


On Fri, 22 Feb 2013, Linus Torvalds wrote:
> On Fri, Feb 22, 2013 at 7:06 AM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
> >>
> >> I prefer to let you guys have the final word on this patch. Whether you
> >> apply it or not, I fear I'll never be entirely happy either way :)
> >> That's the sad fate of dealing with circular dependencies...
> >
> > plus the butt ugly softirq semantics or the lack thereof ...
>
> The softirq semantics are perfectly fine. Don't blame softirq for the
> fact that irq_exit() has had shit-for-brains for a long time.
>
> Just move the whole "invoke_softirq()" thing down to *after* the
> tick_nohz_irq_exit() stuff.

We can't move tick_nohz_irq_exit() before invoke_softirq() simply
because we need to take the timers into account for NOHZ and those can
change when the softirq code runs.

So no, we need an extra check after invoke_softirq() and the same is
true for RCU.

Thanks,

tglx


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/