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

From: Bill Irwin
Date: Tue May 01 2007 - 19:31:41 EST


On Tue, May 01, 2007 at 05:36:06PM -0500, Matt Mackall wrote:
>>> Can we register them lazily at request_irq time?

On Tue, May 01, 2007 at 03:51:25PM -0700, Bill Irwin wrote:
>> 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?

On Tue, May 01, 2007 at 06:15:48PM -0500, Matt Mackall wrote:
> 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.

Well, I don't really know how much of -rt or which pieces of it are
really going in. Otherwise it favors large-scale i386, which people
largely want to ignore/break/etc. I'll err on the side of caution and
not change it.


-- wli
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