[Ksummit-2012-discuss] Topic proposal: Finding and eliminating kernel work creation schemes

[Guenter Roeck]

On Sat, Jun 16, 2012 at 07:54:56AM -0700, Greg KH wrote:
> On Sat, Jun 16, 2012 at 06:53:06PM +0530, Balbir Singh wrote:
> > On Sat, Jun 16, 2012 at 5:17 PM, James Bottomley
> > <James.Bottomley at hansenpartnership.com> wrote:
> > >
> > > I'm sure everyone has a different idea of what is and isn't work
> > > creation within the kernel; for instance some see value in pr_...
> > > replacement for printk(KERN_...).  However if we discuss our pet peeves
> > > in this department, perhaps we can find some of the ones that everyone
> > > agrees serve no useful purpose.  I'll start with mine:
> > >
> > > Although __init and __exit are fine and reasonably well contained, the
> > > massive proliferation of __dev... _mem... __cpu... and their ilk are
> > > getting out of control.  Plus, the amount of memory they save is tiny (a
> > > few pages at best) and finally virtually no-one compiles without
> > > CONFIG_HOTPLUG, so they're mostly nops anyway.  However, for that very
> > > case, we've evolved a massive set of tools to beat ourselves up whenever
> > > we violate the rules of using these tags.  What I'd like to explore is
> > > firstly, can we just eliminate CONFIG_HOTPLUG and make it always y (this
> > > will clear up the problem nicely) or, failing that, can we just dump the
> > > tags and the tools and stop causing work for something no-one cares
> > > about.
> > 
> > Do you expect CONFIG_HOTPLUG to be true even for embedded devices? Android, etc?
> 
> Do you expect to never plug any device into those systems after they
> have been booted?  Never plug those systems into another one?
> 
> Usually that isn't true, so I agree with just dropping CONFIG_HOTPLUG
> and fixing up this __dev mess.
> 

I don't have an opinion on __dev, but dropping CONFIG_HOTPLUG would be an excellent idea.

Guenter