Re: [PATCH] Prevent nested interrupts when the IRQ stack is near overflowing v2

Linus Torvalds
2010-03-25T19:15:49Z

On Thu, 25 Mar 2010, Ingo Molnar wrote:
>
> So the patch below should at most trigger bugs in areas that need fixing
> anyway, and i'm quite sure that under no circumstance would it cause
> unforeseen problems in 'thousands of drivers'.

If we do this, then we should just remove all the IRQF_DISABLED code in
kernel/irq/manage.c too, and basically make IRQF_DISABLED a clear no-op
(still leave it around as a #define, to not break any users).

It won't make it any harder to revert if it causes problems, and that way
there will be no crazy dead code (and comments) left around.

And I just checked: even the 8250 serial driver doesn't use IRQF_DISABLED
any more, so doing that shouldn't cause any latency issues (sure, the
serial driver may interrupt another irq, but another irq can also
interrupt the serial driver as things stand now, so the original latency
issue with fast irq handlers doesn't actually work these days _anyway_).

Linus