Re: [2.4.17/18pre] VM and swap - it's really unusable

Robert Love
2002-01-12T19:24:09Z

On Sat, 2002-01-12 at 13:54, Alan Cox wrote:
> Another example is in the network drivers. The 8390 core for one example
> carefully disables an IRQ on the card so that it can avoid spinlocking on
> uniprocessor boxes.
>
> So with pre-empt this happens
>
> driver magic
> disable_irq(dev->irq)
> PRE-EMPT:
> [large periods of time running other code]
> PRE-EMPT:
> We get back and we've missed 300 packets, the serial port sharing
> the IRQ has dropped our internet connection completely.

We don't preempt while IRQ are disabled.

Robert Love