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

From: Daniel Phillips (phillips@bonn-fries.net)
Date: Sun Jan 13 2002 - 17:06:56 EST

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On January 12, 2002 07:54 pm, 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)
inc task's preempt inhibit

> 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 are ok
        dec tasks's preempt inhibit
        jmp if nonzero

--
Daniel
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