Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

From: Mikulas Patocka
Date: Wed Apr 25 2018 - 19:00:41 EST

On Wed, 25 Apr 2018, James Bottomley wrote:

> > > Do we really need the new config option?ÂÂThis could just be
> > > manually tunable via fault injection IIUC.
> >
> > We do, because we want to enable it in RHEL and Fedora debugging
> > kernels,Âso that it will be tested by the users.
> >
> > The users won't use some extra magic kernel options or debugfs files.
> If it can be enabled via a tunable, then the distro can turn it on
> without the user having to do anything. If you want to present the
> user with a different boot option, you can (just have the tunable set
> on the command line), but being tunable driven means that you don't
> have to choose that option, you could automatically enable it under a
> range of circumstances. I think most sane distributions would want
> that flexibility.
> Kconfig proliferation, conversely, is a bit of a nightmare from both
> the user and the tester's point of view, so we're trying to avoid it
> unless absolutely necessary.
> James

BTW. even developers who compile their own kernel should have this enabled
by a CONFIG option - because if the developer sees the option when
browsing through menuconfig, he may enable it. If he doesn't see the
option, he won't even know that such an option exists.