Three or more different kernel versions?

eeckwrk99 · gentoo-sources-5.15.52

I'm using

alamahant · Advocate Joined: 23 Mar 2019 Posts: 3879

You cant.
Although gentoo-sources is slotted it is slotted with the full version of the kernel.
See
https://packages.gentoo.org/packages/sys-kernel/gentoo-sources

eeckwrk99 · Posted: Mon Jul 04, 2022 9:26 pm Post subject:

alamahant · Advocate Joined: 23 Mar 2019 Posts: 3879

I suppose by

Goverp · Advocate Joined: 07 Mar 2007 Posts: 2006

eeckwrk99 · Posted: Sat Aug 13, 2022 2:17 pm Post subject:

Hu · Moderator Joined: 06 Mar 2007 Posts: 21631

What is the point of keeping multiple major kernel series like this? I can see keeping a backup kernel version around until you are sure the new one is good, but usually that is only one backup kernel, and usually within the same series. If you explain your goal, we might be able to suggest a better way to achieve that goal.

eeckwrk99 · Posted: Sat Aug 13, 2022 4:34 pm Post subject:

Hu · Moderator Joined: 06 Mar 2007 Posts: 21631

That is an exceedingly slow kernel build. Mine complete in under 3 minutes.

I see the value in being able to go back to older branches, but I don't see the point in proactively keeping all those older branches installed just in case you might need them. If you hit a regression, install an older kernel as needed to deal with it. Gentoo's ability to offer multiple kernel versions also means it's easy enough to bring in old kernel sources later. You ought to always keep at least one older known-good kernel when upgrading, so you also have the option of falling back to that while getting the latest of an old line.

eeckwrk99 · Posted: Sat Aug 13, 2022 5:50 pm Post subject:

Genone · Posted: Sun Aug 14, 2022 9:44 pm Post subject:

Goverp · Advocate Joined: 07 Mar 2007 Posts: 2006

Genone · Posted: Mon Aug 15, 2022 12:37 pm Post subject:

logrusx · Veteran Joined: 22 Feb 2018 Posts: 1532

Hu · Moderator Joined: 06 Mar 2007 Posts: 21631

madmin · n00b Joined: 04 Nov 2018 Posts: 26

- Avoiding a kernel to be removed by "emerge --depclean -va" once a newer version is deploy:

A trash trick is to remove that version from the database.

The installed packages database is in /var/db/pkg/. Simply remove the whole directory of the version[s] you want to e ignored by emerge once installed.
Note: move that or these directories in some other place, outside of /var/db/pkg, at first, to not trash your system by trusting me blindly ; )

I used that to avoid to have to rebuild my kernel after each and every world update when I was happy with that version. This because I configure my kernels manually and "make oldconfig" is time consuming.

It can be done with any kind of package but I strongly recommend NOT to do that for standard software as emerge is there to keep systems clean.

- Avoiding kernel rebuild:

Kernels are sources, once compiled and pushed in /boot (and /lib/modules) or wherever you want, there is no need to rebuild them all after each emerge process. Here, my systems are requesting kernel rebuild when emerge tries to install drivers relying on present kernel AND gcc version has been changed since I compiled the mentioned kernel. This happens (to me) mainly when nvidia-drivers are about to be merged.

- rebuilding a already deployed kernel using multiple threads:

make clean
make -j12 bzImage modules
make modules_install

The point is to separate "make modules" and "make modules_install". On a clean kernel sources tree, asking "make" command to do all three tasks (kernel/bzImage, modules and modules installation/modules_install) will hang. Some issues with install order if I remember correctly.

Note that there are other options than bzImage. These are those I use for years, since I found a tutorial on how to compile my own kernel.

Cheers

Hu · Moderator Joined: 06 Mar 2007 Posts: 21631

Deliberately breaking the package database is a terrible way to solve this, particularly since adding that kernel version to @world ought to protect it from a broad depclean, and is easier to undo.