Re: [gentoo-user] How does Portage prioritze emerges in emerge world?

[Zac Medico]

Holly Bostick wrote:
> OK, I take it back.
>
> I said that the situation of upgrading a kernel with the 'symlink' USE
> flag active occurring at the same time as a (particular) program needing
> to compile against a configured kernel was not likely to occur all that
> often, but I was wrong. It's happened again today, but with a different
> program than the ones I normally keep an eye on.
>
> The good thing is that I (think I) see what the problem is.
>
> The problem is that Portage emerges the new kernel before (almost)
> everything else, without regard for whether the 'symlink' USE flag is
> active, and whether or not any of the other programs proposed to emerge
> need to compile against a configured kernel source-- or rather, the
> currently-running kernel, which the symlink most likely pointed to
> before Portage changed it via a previous emerge.
>
> Honestly, there's really no reason (that I can see) to emerge a kernel
> source before everything else, since the kernel source is useless until
> at the very least configured, and preferably compiled and installed, and
> since you're in the middle of an emerge -uwhatever world, you can't
> reasonably configure and compile the new source until the entire
> operation is finished. Yeah, OK, technically you can, but it's not
> really something that an ordinary person would do, I think.

I like to manage the kernel sources myself so I always keep a kernel package in package.provided.

mkdir -p /etc/portage/profile
echo sys-kernel/gentoo-sources-2.6.14-r3 >> /etc/portage/profile/package.provided

>
> And if the 'symlink' USE flag is active, emerging the kernel sources
> before everything else-- which may include packages that must compile
> against a configured kernel, with the assumption that the
> /usr/src/symlink points to such a kernel, which it no longer does
> because the symlink has been changed during a previous emerge and you
> have not had time to configure the newly-emerged kernel-- is a real
> problem. I just had to open another term, su to root, run MC to change
> the symlink-- and got it wrong because I had a second unconfigured
> kernel  (2.6.14-r2; 2.6.14-r3 was being installed) that I forgot I had
> not yet upgraded to), so had to change the link again to the *real*
> running kernel (2.6.14) and emerge --resume. And of course I'll have to
> eventually change the symlink back manually in order to actually manage
> the new kernel. Which means I have to remember to do that-- which is not
> the point of having the 'symlink' USE flag active.
>
> It seems to me that this could all be avoided if Portage emerged a new
> kernel *last* in the list if the 'symlink' USE flag is active for kernel
> emerges-- then everything in the list that needed a configured kernel
> would have one (the currently-running kernel), the emerge would complete
> normally, and the symlink would be changed at the end of the procedure
> so that my next operation could be to upgrade the kernel, which seems to
> me a reasonable and ordinary order of operation (emerge -u** world, then
> configure and compile new kernel and run module-rebuild).
>
> Am I doing things wrong, or is this a valid enhancement request for b.g.o?
>
> Holly

The portage developers will not add a special case for kernel packages, so any reordering/prioritization would have to be done in a generic way that is usable for any type of package.  Also, it seems desireable to compile against the latest kernel that is installed.

Perhaps it would make sense to have a default kernel config that is used to configure the kernel sources automatically (make oldconfig; make modules_prepare) after a new kernel is installed?  Something like this could be done ebuild postinst phase (when symlink is created).  It is planned for future versions of portage to have pre/post phase hooks, which will allow users to define actions such as this via /etc/portage/bashrc:

http://thread.gmane.org/gmane.linux.gentoo.portage.devel/1107

Zac
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