Re: [PATCH][RFC] 4K stacks default, not a debug thing any more...?

Phillip Susi
2007-07-18T17:33:25Z

Alan Cox wrote:
>> Why do the two pages have to be physically contiguous? The stack just
>> needs to be two contiguous pages in virtual memory, but they can map to
>> any two pages anywhere in physical memory.
>
> Historically we allowed DMA off the stack on old x86 systems. Removing
> that while a good idea would take a lot of auditing. We also have a very
> limited vmalloc window for mapped pages and filling that with stacks
> would be bad.

Wow, DMA off the stack? That's just crazy.