Re: [PATCH V2] xfs: introduce CONFIG_XFS_WARN

Dave Chinner
2013-04-25T21:44:11Z

On Thu, Apr 25, 2013 at 09:07:49AM -0500, Chandra Seetharaman wrote:
> On Thu, 2013-04-25 at 08:58 +1000, Dave Chinner wrote:
> > On Wed, Apr 24, 2013 at 01:39:52PM -0500, Chandra Seetharaman wrote:
> > > Hi Dave,
> > >
> > > Since this solution is for production environment, would it be valuable
> > > to have a sysctl variable to allow enabling/disabling XFS_WARN, as
> > > opposed to needing to recompile the module afresh ?
> >
> > The idea is that distros enable it on the debug kernel packages
> > rather than using CONFIG_XFS_DEBUG=y. Hence if someone has a
> > problem, they just install the debug kernel and they get all this
> > additional checking.
>
> Thanks for the clarification.
>
> I was thinking that CONFIG_XFS_DEBUG would be enabled in the distro's
> debug kernel and this new option is in addition to that. Hence, my
> question.

If you are shipping a debug kernel with CONFIG_XFS_DEBUG, then you
don't want your customers running that debug kernel for very long.
CONFIG_XFS_DEBUG changes allocation algorithms to improve test
coverage and this causes accelerated filesystem aging....

CONFIG_XFS_WARN is designed to be used instead of CONFIG_XFS_DEBUG
in these situations - we get more verbose checking, but without the
down sides associated with all the algorithmic changes in
XFS_DEBUG...

> So, with this new config option, CONFIG_XFS_DEBUG will only be used in
> development environment, correct ?

That's what I has always been intended for.

Cheers,

Dave.
--
Dave Chinner
david@fromorbit.com