Re: 4k stacks in 2.6

Brian Gerst
2004-05-27T14:18:44Z

Andrea Arcangeli wrote:

> On Thu, May 27, 2004 at 02:45:51PM +0200, Ingo Molnar wrote:
>
>>are a bit belated. I only reacted to Andrea's mail to clear up apparent
>>misunderstandings about the impact and implementation of this feature.
>
>
> note that there is something relevant to improve in the implementation,
> that is the per-cpu irq stack size should be bigger than 4k, we use 16k
> on x86-64, on x86 it should be 8k. Currently you're decreasing _both_
> the normal kernel context and even the irq stack in some condition.
> There's no good reason to decrease the irq stack too, that's cheap, it's
> per-cpu.

The problem on i386 (unlike x86-64) is that the thread_info struct sits
at the bottom of the stack and is referenced by masking bits off %esp.
So the stack size must be constant whether in process context or IRQ
context.

--
Brian Gerst