I have installed Debian (dual-boot with XP).
Also I have one free partition and I thinking about how to install Gentoo at this free partition. As far as I know it's possible to install Gentoo from other linux.
But I'm not sure how to use my free space.
Should I create /boot and / partitions for Gentoo?
Or can I use existing grub installation and create only root / for Gentoo?
Currently I haven't separate boot partition for my Debian:

Also I'm not sure about swap: can I use existing sda5 swap for Gentoo as well as for Debian?

Thanks.

Yes, you can use the same swap partition for both Debain and Gentoo.

Separating /boot and / or having them on the same partition is your choice. It will run either way. I know some people recommend the separation, I have never done that.

How about your /home directory? I would separate it to a separate partition. When you re-install, you will not have to move all your user data if /home is on its own partition. If it is on the same partition as /, then re-installation is much more work.

Thanks for reply!
Yes, I done one partition (/ only, without /boot). Also I never made separate /home.

So I walking through installation process and now I have kernel and initramfs built. Just one warning about /boot mount point. I think it could be solved later (or I'm wrong?).
Now I stopped at handbook chapter "7.e. Kernel Modules".
Find command shows a lot of built kernel modules and I'm not sure which of them I need to include into /etc/conf.d/modules file

Sorry, I have no experience with a Gentoo install.

Best of luck with it.

OK, thanks!

You shouldn't need to worry much about kernel modules nowadays. If you need, then you will notice

About Grub, well, it lives in your MBR usually, so you don't need to install it again, but you will need to know how it works and setup it correctly so it can find the kernels for all your distros. Sharing /boot can sometimes help with that. I find that kind of setup easier to maintain myself, but I guess it's a matter of personal preference.

Sharing /home is not difficult if you plan to use two non-matching user accounts, one for each distro. Using the same $HOME with the same UID is another matter, because different program versions will break the config files every once in a while. That's specially true if you will be using two different kde versions (even if only slightly different) across distros.

OK, I have the base system installed and GRUB loading my system properly. I added new menuentry to GRUB menu manually and it works fine.
Now I'm ready to install x-server and desktop. But it is other topic.