Re: [CHECKER] large stack variables (>=1K) in 2.4.4 and 2.4.4-ac8

Andi Kleen
2001-05-25T08:21:39Z

On Fri, May 25, 2001 at 04:53:47PM +1000, Keith Owens wrote:
> The only way to avoid those problems is to move struct task out of the
> kernel stack pages and to use a task gate for the stack fault and
> double fault handlers, instead of a trap gate (all ix86 specific).
> Those methods are expensive, at a minimum they require an extra page
> for every process plus an extra stack per cpu. I have not even
> considered the extra cost of using task gates for the interrupts nor
> how this method would complicate methods for getting the current struct
> task pointer. It is not worth the bother, we write better kernel code
> than that.

When you don't try to handle recursive stack/double faults it only requires
a single static stack per CPU. With some tricks and minor races it is also
possible to handle multiple ones.

-Andi