Re: [PATCH 1/2] Avoid bio_endio recursion
From: Alan Cox
Date: Wed Jul 02 2008 - 04:19:24 EST
On Wed, 2 Jul 2008 00:09:22 -0400 (EDT)
Mikulas Patocka <mpatocka@xxxxxxxxxx> wrote:
> > Right, that wont work of course. Completions are typically done through
> > a softirq, so it is not currently done with hard interrupts disabled.
>
> I thought, from hardirq - that's what IDE is doing. And they are called
Even IDE will sometimes complete from a timer on an error.
> And does local_irq_restore() need to execute even more costy "popf" when
> it makes a transition from disabled to disabled state? What's
> local_irq_restore semantics --- is it allowed to use local_irq_restore for
> transition from interrupt-enabled state into interrupt-disabled state?
If you are worried about performance the network layer has _irq variants
of various functions that are faster and can only be called from the
right context (eg kfree_skb_irq), so you could do two versions of that
code.
Alan
--
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/