Re: [2.6 patch] i386: always use 4k stacks

Arjan van de Ven
2005-11-15T13:24:20Z

On Tue, 2005-11-15 at 14:18 +0100, Tue, 15 Nov 2005 14:18:51 +0100
wrote:
> El Mon, 14 Nov 2005 23:47:10 -0700,
> "Jeff V. Merkey" <jmerkey@wolfmountaingroup.com> escribió:
>
> > Great point, and you are correct that MS DOS had bigger stacks than 4K.
> > Onward through the fog ....
>
>
> And Linux had stacks bigger than 4K until recently and could be made
> bigger again.

well ......

in 2.4 kernels you had a 4K stack as well (even though it was 8Kb in
size, you lost 1.5Kb to the task struct and you lost 2 to 2.5 Kb to irq
context, net usable was 4Kb). In 2.6 the task struct moved off the
stack, and the 4KSTACK feature allowed you to split the irq stack usage
off to a seperate stack, still giving you 4Kb available.. that's still
the same as 2.4 effectively. 2.6 also has (and I wish it becomes "had"
soon) an option to get 6Kb effective stack space instead. This is an
increase of 2Kb compared to 2.4.