Re: [2/6] add config option to vmalloc stacks (was: Re: [-mm patch] i386: enable 4k stacks by default)

[Matt Mackall]

On Tue, May 01, 2007 at 03:51:25PM -0700, Bill Irwin wrote:
> On Mon, Apr 30, 2007 at 08:15:11PM +0100, Christoph Hellwig wrote:
> >> So if you want to invest some time into getting this into mergeable
> >> shape I'd suggest you redo the patch series in the following way:
> >>  patch 1: dynamic allocated irq stacks
> 
> On Tue, May 01, 2007 at 05:36:06PM -0500, Matt Mackall wrote:
> > Can we register them lazily at request_irq time?
> 
> These IRQ stacks are per-cpu, not per-IRQ. It may make sense to
> implement per-IRQ stacks, in which case dynamic allocation at the time
> of request_irq() will make sense.
> 
> Would you like me to implement per-IRQ IRQ stacks?

It's probably the "right" thing to do, but it does have higher
overhead for most systems.

But it also gives a very obvious migration path to -rt's irq threads.

-- 
Mathematics is the supreme nostalgia of our time.
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