Re: [RFC 2/2] x86_64: expand kernel stack to 16K

Dave Jones
2014-05-30T00:29:49Z

On Fri, May 30, 2014 at 10:21:13AM +1000, Dave Chinner wrote:
> On Thu, May 29, 2014 at 08:06:49PM -0400, Dave Jones wrote:
> > On Fri, May 30, 2014 at 09:53:08AM +1000, Dave Chinner wrote:
> >
> > > That sounds like a plan. Perhaps it would be useful to add a
> > > WARN_ON_ONCE(stack_usage > 8k) (or some other arbitrary depth beyond
> > > 8k) so that we get some indication that we're hitting a deep stack
> > > but the system otherwise keeps functioning. That gives us some
> > > motivation to keep stack usage down but isn't a fatal problem like
> > > it is now....
> >
> > We have check_stack_usage() and DEBUG_STACK_USAGE for this.
> > Though it needs some tweaking if we move to 16K
>
> Right, but it doesn't throw loud warnings when a specific threshold
> is reached - it just issues a quiet message when a process exits
> telling you what the maximum was without giving us a stack to chew
> on....

ah, right good point. That would be more useful.

Dave