Best Way to Get at Extra Bit of High Memory?
 

I'm running Slack 10 with the 2.4.26 kernel with a gig of ram. Of course, in its current state, the kernel only recognizes 883 meg of that ram, and I'd really like to utilize the rest.

From what I can ascertain, there are several ways of going about this:


1. Enable HIMEM support.

- As far as I can tell, this might not be difficult, though I have yet to find out exactly to go about it. Kcontrol won't let me write to /usr/src/linux/.config, and I can't find any manual instructions yet. Also, in several instances I have read that HIMEM support can cause performace drops.


2. Low Memory Split Patches.

- Patches exist that apparently change the threshold between what the kernel considers high and low memory. However, I can't find one for the 2.4.26 kernel.


3. Install a Brand New Kernel

- This goes against the grain of my philosophies of "if it ain't broke, don't fix it" and "never swat a fly with a Buick". In other words, a new kernel to solve a relatively small problem such as mine smacks of overkill to me. Besides, if I even manage to successfully install a new, HIMEM enabled kernel, won't I be running the same risk of performance drops as if I had simply enabled HIMEM support on my current kernel?



Anyway, I'm uncertain of how to proceed. Please advise.

Use 2 and 3. The Con Kolivas patch moves the threshold to 1G. It doesn't have the additional overhead of simply enabling HIGHMEM. It may seem like overkill, but it works. I don't see any patches for the 2.4 kernel, so 2 and 3 is really just one option.

I would say the order of preference for possible solutions (best to worst) is:

1) New 2.6 kernel with Con Kolivas patch
2) Keep running what you have (depending on what you do, performance gains may be minimal anyway)
3) Enable HIGHMEM (This is last because it is likely that any performance gain from the additional RAM will be negated by the additional overhead of running HIGHMEM)

It's really a tie for 1 & 2. I'd go with 1 just because you can continue running the 2.4 kernel while you work on the 2.6 kernel (just make sure to leave it as a LILO boot option). Seems like the best solution. You continue to run the current kernel until you have the new kernel running smooth.

I was afraid somebody would say that.

Once question: will a generic 2.6.xx kernel from kernel.org suffice for Slack distro? It is my understanding that Slackware doesn't screw around with distribution-specific kernels like, say, Mandrake did/does, but I'm not certain of that.

Also, can you (or anyone) recommend a good site/tutorial for kernel-compiling newbies such as my nervous self?

Thanks for the quick feedback, shilo.

IamI,

you can refer the sticky post posted by DaOne for kernel compiling ...or if you have slack CD 10.0 or 10.1 just upgrade it from the extra (CD2). just follow the upgrade instruction

A) Slackware uses a "vanilla" kernel. The one from kernel.org is perfect.

B) I like this guide: http://www.linuxquestions.org/questi...icle&artid=408

I don't recommend the 2.6 kernel included with Slackware. Just my own preference. Lot's of people seem to be happy with it, though.

Note, the only hard part is picking the right configure options. The rest is pretty mechanical. Fortunately, the above guide shows how to make sure your old kernel still boots. That's the best way to do things. Eventually, you get the hang of the configuration options.

Don't freak out if the new kernel doesn't work on the first (or third :) ) try. The 2.4 kernel will still be there.