Which distributions maintain a kernel package with grsecurity support

I have an old notebook which has similar configuration:

-512 MB RAM
-40GB HDD
-Pentium M 1,5GHz
-Intel integrated graphics

I recently installed XUbuntu 12.04 on it.

XUbuntu itself is pretty light. After boot it uses around 250MB and overall performance is decent/good.

However when you start using Firefox (I believe other modern browsers will be similar) you will have a big performance penalty, mostly due to lack of RAM. Depending on amount of tabs and the pages you are browsing, you'll have swapping.

Using Debian/Ubuntu alt you'll have a lot more control over what is installed, you can choose an even lighter desktop/graphic environment. On the other hand, you'll probably have to configure more stuff than with regular Ubuntu. But if you plan to use a browser to view anything but simple HTML pages low on images, sooner or later you'll run out of physical memory. It is, in my experience, what eats up more memory and what degrades performance the most.

(I'm a grsecurity developer.)

jsbillings's answer is based on an email post discussed in an LWN article.

The important context here is that neither grsecurity nor PaX developers were involved in that mailing list discussion. The PaX Team's comment to the LWN article clears this up. We've never submitted the patches for mainline inclusion. One simple reason is that we're the ones with the ideas and implementations, which upstreaming would not solve. Furthermore, we'd have to engage in tiresome mailing list arguments with a group of developers who are very much anti-security (see my 2012 H2HC presentation for more discussion of this). We have limited time and resources, so we choose to spend it in the most effective way possible: creating the security technology of tomorrow and making it available to everyone for free. As the PaX Team mentions in their comment, we have a particular encompassing view of security and also thus don't believe there's much merit in the splitting-off and upstreaming of individual features.