On Fri, Apr 28, 2017 at 11:34:34PM +0200, Peter Zijlstra wrote: > On Fri, Apr 28, 2017 at 01:49:49PM -0700, Darren Hart wrote: > > > > Non-modular drivers do not scale. This is a serious issue considering > > > > the growth rate of the kernel. > > > > > > Again, this is an oversimplification that doesn't reflect reality. > > > There are many valid reasons why some drivers be built-in only. The > > > whole world isn't a distro looking to say "=m" to every config option > > > simply because they don't have the time or resources to actually triage > > > them all and see what is relevant for their use case(es). > > > > > > > The point is valid though, and something we need to be keeping an eye on, > > especially with all the non-architectural SoC feature drivers we're seeing code > > roll in for. I appreciate you raising the concern Jean. > > FWIW: > > There's things like ACPI-Processor-Idle and intel_idle that need to be > built-in for correctness sake. > > They can mark the TSC unstable, and this should be done before we run > userspace, which with unstable TSC could see wobbly time before we kill > the TSC. > > This is a somewhat non-obvious case, and on the face of it those could > be modular drivers. But building them as modules gets them loaded far > too late if ever. > > These are subtle things and easily overlooked. Thanks Peter, I will be sure to do my due diligence in determining why something may be bool before applying incoming patches to change that. This isn't clearly documented in intel_idle for example, but it is at least explicitly described in the git log for the Kconfig. -- Darren Hart VMware Open Source Technology Center
