calcru-triggered panic?

[Scott Long]

John Birrell wrote:
> On Wed, Nov 29, 2006 at 03:40:38PM -0700, Scott Long wrote:
>> It's probably less of an issue now that it used to be, since I/O is
>> decoupled through GEOM threads.  In 4.x, you could have a stack that
>> went from the syscall, through VFS, UFS, the block layer, CAM, and 
>> finally the device driver.  When I was working on RAIDFrame, adding
>> just a couple hundred bytes of stack usage would cause it to blow out.
>> But as I said, it might not be as much of an issue now.
> 
> Is it possible to check how deep the stack is and avoid using a stack
> buffer if too deep?
> 
> --
> John Birrell

I don't know how to do it in a platform-independent way.  For i386,
I'd check %esp and see if it's getting close to a 2x page boundary.

Scott