Re: [PATCH 2/6] Container Freezer: Make refrigerator always available

[Matt Helsley <matthltc@us.ibm.com>]

On Sat, 2008-08-02 at 00:53 +0200, Rafael J. Wysocki wrote:
> On Friday, 1 of August 2008, Matt Helsley wrote:
> > 
> > On Fri, 2008-08-01 at 16:27 +0200, Thomas Petazzoni wrote:
> > > Hi,
> > > 
> > > Le Thu, 31 Jul 2008 22:07:01 -0700,
> > > Matt Helsley <matthltc@us.ibm.com> a écrit :
> > > 
> > > > --- a/kernel/Makefile
> > > > +++ b/kernel/Makefile
> > > > @@ -5,7 +5,7 @@
> > > >  obj-y     = sched.o fork.o exec_domain.o panic.o printk.o \
> > > >  	    cpu.o exit.o itimer.o time.o softirq.o resource.o \
> > > >  	    sysctl.o capability.o ptrace.o timer.o user.o \
> > > > -	    signal.o sys.o kmod.o workqueue.o pid.o \
> > > > +	    signal.o sys.o kmod.o workqueue.o pid.o freezer.o \
> > > 
> > > I have the impression that the code in kernel/power/process.c was
> > > compiled only if CONFIG_PM_SLEEP was set. Now that the code has been
> > > moved to kernel/freezer.c, it is unconditionnaly compiled in every
> > > kernel. Is that correct ?
> > >
> > > If so, is it possible to put this new feature under some
> > > CONFIG_SOMETHING option, for people who care about the kernel size ?
> > 
> > 	How about making it depend on a combination of CONFIG variables?
> > Here's an RFC PATCH. Completely untested.
> > 
> > Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
> 
> Can you please also make the contents of include/linux/freezer.h depend on
> CONFIG_FREEZER instead of CONFIG_PM_SLEEP?

Good point -- I'll add that to this patch and repost.

> Also, I'm not really sure if kernel/power/Kconfig is the right place to define
> CONFIG_FREEZER.

	There's no nice place to put it since we're dealing with CONFIG_
variables in two different Kconfig files. I put it in
kernel/power/Kconfig because I wasn't certain Kbuild would do the right
thing if I referenced PM_SLEEP from init/Kconfig.

> Perhaps we should even move freezer.c from kernel/power to kernel

It's already there. Perhaps you meant something else
(kernel/power/process.c?)?

> and define CONFIG_FREEZER in Kconfig in there.  Andrew, what do you think?

The Kconfig files in kernel/ are Kconfig.hz and Kconfig.preemt which
don't seem appropriate. I suppose we could add another (perhaps
Kconfig.cgroup).

Thanks for the review!

Cheers,
	-Matt