make buildkernel does not respect KERNCONF or JOBS in /etc/make.conf

[Ian Lepore]

On Mon, 2016-12-12 at 20:22 -0800, Kevin Oberman wrote:
> On Mon, Dec 12, 2016 at 4:20 PM, Herbert J. Skuhra <herbert at mailbox.o
> rg>
> wrote:
> 
> > 
> > Kevin Oberman skrev:
> > > 
> > > 
> > > Clearly the documentation is a bit behind the times. For some
> > > time people
> > > have used KERNCONF to build multiple kernels, but that was a
> > > lucky things
> > > that was not officially supported. It just happened to work.
> > > Then, with
> > > 11.0, it no longer did in many cases sue to changes in the kernel
> > > build
> > > system. When people complained, there did not seem to be a way to
> > > fix
> > this
> > > 
> > > without blocking future goals in speeding up and enhancinghte
> > > standard
> > > kernel build.
> > > 
> > > The result was BUILDKERNELS. It was specifically designed to
> > > allow the
> > > building of multiple kernels and the appropriate modules. This
> > > would
> > always
> > > 
> > > take longer and use more disk space, but it would work reliably.
> > > Now, bit
> > > building a single, local kernel, KERNCONF is the best way, though
> > > I
> > suspect
> > > 
> > > that it make only a small difference until new capabilities are
> > > added
> > later
> > > 
> > > in the life of 11.
> > > 
> > > So, while it seems the man pages need to catch up, building
> > > multiple
> > > kernels should be done with KERNCONF in either make.conf or
> > > src.conf and
> > > multiple kernels with BUILDKERNELS.
> > > 
> > > This is from my recollection of the discussion thread. I'll admit
> > > to
> > being
> > > 
> > > too lazy to go find and read all of it. I suspect it was on
> > > current@,
> > but
> > > 
> > > I'm not even sure of that.
> > ???
> > 
> > From /usr/src/Makefile.inc1:
> > 
> >    1137 .if ${TARGET_ARCH} == "powerpc64"
> >    1138 KERNCONF?=      GENERIC64
> >    1139 .else
> >    1140 KERNCONF?=      GENERIC
> >    1141 .endif
> >    [...]
> >    1149 BUILDKERNELS=
> >    1150 INSTALLKERNEL=
> >    1151 .if defined(NO_INSTALLKERNEL)
> >    1152 # All of the BUILDKERNELS loops start at index 1.
> >    1153 BUILDKERNELS+= dummy
> >    1154 .endif
> >    1155 .for _kernel in ${KERNCONF}
> >    1156 .if exists(${KERNCONFDIR}/${_kernel})
> >    1157 BUILDKERNELS+=  ${_kernel}
> >    1158 .if empty(INSTALLKERNEL) && !defined(NO_INSTALLKERNEL)
> >    1159 INSTALLKERNEL= ${_kernel}
> >    1160 .endif
> >    1161 .endif
> >    1162 .endfor
> > 
> > So setting BUILDKERNELS has no effect.
> > 
> > --
> > Herbert
> > 
> I think you miss the significance. BUILDKERNELS only is used to build
> the
> kernels. It is not used by installkernel as installing two kernels
> does not
> make sense. It is ONLY used to build multiple kernels. KERNCONF is
> still
> used to specify the kernel, with attendant modules, to be installed.
> 
> I should also mention that, if you want to install a new kernel
> without
> overwriting the old kernel and modules (/boot/kernel.old/), "make
> reinstallkernel". It replaces the existing kernel instead of renaming
> the
> kernel directory to kernel.old. I find this very handy, but it is
> poorly
> documented. So, if you want to install GENERIC and not lose your last
> working kernel, "make reinstallkernel KERNCONF=GENERIC". That will
> blow
> away the bad kernel and modules and install GENERIC. Note that it
> does not
> touch the /usr/obj directory that PUMPKIN is built in, so PUMPKIN and
> similarly be reinstalled.
> 
> The man page for src.conf is automatically generated and only lists
> those
> values which are specific to src.conf (WITH_ and WITHOUT_) and
> describes
> its use. It is used as input for system builds and installs but
> should not
> be accessed for any other purpose. make.conf is always read by make
> with no
> regard to what is being made. (N.B. I believe that some people have
> ignored
> this in some ports stuff.) Anything that is put into make.conf may be
> placed in src,conf if you only want to have it used when
> building/installing the kernel and world.
> 
> I'm probably forgetting something, but I hope this explains it a bit.

The BUILDKERNELS variable is part of the build system's internal
machinery for building multiple kernels when the user has set KERNCONF=
to more than one name.  It's not a thing that a user can set.

-- Ian