Re: [RFC][PATCH] kmap_atomic_push

From: David Howells
Date: Thu Oct 08 2009 - 19:01:01 EST


Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:

> I can think of code that does a lot more than that, suppose you have
> both KM_USER[01], get an interrupt that takes KM_IRQ[01], take an NMI
> that takes KM_NMI.

But whilst the interrupt might want to use two slots, it's probably a bug for
it to want to access the mappings set up by whatever called KM_USER[01] - so
it can probably reuse those slots, provided it puts them back again.

Similarly for NMI taking KM_NMI - it probably shouldn't be attempting to
access the mappings set up by the normal mode or the interrupt mode - in which
case, why can't it reuse those slots?

> Maybe we can stack the SOFTIRQ ones in as well ;-)

Ditto.

David
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