James Simmons announced innocently enough on the lkml, "Just to let you know I created a bitkeeper repository for the framebuffer layer." M. R. Brown replied a couple hours later, "Please tell us that primary framebuffer/input/console development will continue in the CVS drop-in tree on SourceForge? "

This paper presents the results of a benchmark test conducted on a 58-node Cluster 1300 system, simultaneously running eight instances of e-Business Trade 2 benchmark tests on Redhat Linux. This solution mounted in only three racks supported 800,000 users, serving an unprecedented 12,547 requests/sec with an average response time of 0.27 sec/request.

Richard Gooch pointed out that the serial driver was broken in 2.4.19-pre7. Alan Cox explains, "Yes. Someone put the HCDP below not above the basic x86 ports. Tweak include/asm-i386/serial.h and that should be well."

So if you're going to use 2.4.19-pre7 and need your serial port, then you need to apply this patch.

Due to increased spam on the netfilter mailinglist, which is devoted to issues regarding the Linux 2.4/2.5 Netfilter framework, the list maintainer and de facto leader of the Netfilter community, Harald Welte, has made the list "subscribers-only", which prevents people not a member of the list from posting messages on it. This action will prevent any spammers from posting to the list.

Harald also noted in his e-mail that to catch bug reports and legitimate e-mail, he would "manually moderate all rejected mailinglist postings."

Below is the full e-mail.

Mike Fedyk asked on the lkml why the -aa VM update hasn't gone into 2.5 yet. Andrew Morton, who recently split the large -aa update into smaller pieces for 2.4 inclusion explained that now was the wrong time for such an effort. Andrew's current focus in 2.5 is the buffer layer, and because of the intamacy between this layer and the VM, adding the -aa patches "would represent some wasted effort."

Also mentioned was the possibilty that 2.5 will use Rik van Riel's rmap VM, and hence tuning the existing VM would again be "wasted effort". In summary, Andrew offered, "So. My vote would be that unless the VM is actually impeding developers who are working on other parts of the kernel (it is not) then just leave it as-is for the while.".

It was also pointed out that the -aa patches are currently being merged into the 2.4 stable kernel.

John Looney recently posted to the lkml, asking about the possibilty of one computer serving multiple users. That is to say, multiple keyboards, mice, monitors, etc, hooked up to a single server. The advantages of such a setup in a lab type environment are obvious.

The following discussion ranges through several technical issues with such a configuration, including a kernel limitation of one virtual terminal active at a time, and the typical lack of quality in long video cables. However, none of the issues raised are unbeatable. James Simmons, for example, has been working on cleaning up the virtual terminal code, with many related fixes already merged into Dave Jones' tree.

Another hack exists. Miguel Freitas has a page titled, Multiple local XFree users under Linux on which he details using multiple instances of XFree86 and a dual-head video card to support two keboards/mice/monitors.

Today Oskar Andreasson has released version 1.1.0 of his iptables-tutorial package, a series of documents explaining netfilter to the layperson. He mentions quite clearly that he would appreciate it if netfilter coders/experts would "if possible, please have a closer look at the tutorial."

The tutorial can be downloaded at
http://www.boingworld.com/workshops/linux/iptables-tutorial

Below is the full e-mail message.

Byron Stanoszek posted a small patch to the lkml, his efforts at adding 32MB of video card RAM to the system RAM pool on his aging 586. A problem with this effort is the significantly slower speed of video RAM. For this reason, it has been suggested that he turn the video RAM into a block device which could then be added as a fast swap device.

An earlier lkml thread (from April 2000) was also referred to in which the same idea was discussed.

A recent thread on the lkml discussed the "OOM killer". The OOM (out of memory) killer has the task of choosing which process(es) to kill when the VM runs out of memory. Rik Van Riel has a full explanation of the OOM killer here.

Andrew Morton, who's been working on dividing the latest -aa VM into smaller pieces for mainline inclusion, submitted a patch about which he says:

"I have incorporated the oom killer into try_to_free_pages(), along with a tunable which defines how hard we work before killing something. It is *extremely* conservative. As it should be. The VM will spin madly for five or ten seconds before giving up and calling the oom killer. And then another five seconds elapses before the oom killer decides to actually kill something. It works."

The thread goes on to compare the mainline VM with the -aa VM. It also looks at ways to further tune the OOM killer.

The latest LWN kernel summary is out. It includes some interesting news about dealing with discontiguous memory.

Alexis Carvalho asked on the lkml, "Does anyone know of any implementation of soft-updates over ext2?" He went on to explain that he was intending to implement this as a project for grad school. The discussion that followed considered some of the pro's and con's of adding soft-updates to ext2.

For further reading, see our earlier interview with Theo de Raadt in which there's a lengthy discussion of soft updates versus journaling. Theo also recommends this USENIX paper.

The thread also discusses the tux2 filesystem, which uses a phase tree algorithm. Find the original (Aug 2000) announcement here.

When upgrading to the latest kernel, it's generally preferable to apply one of the two major VM patches. One of the patches is maintained by Andrea Arcangeli, the author of the current standard 2.4 kernel VM. In a recent email, Andrea referrs to his vm-33 patch, recommending that you "never use a 2.4 kernel without first applying this vm patch". Andrew Morton also recently broke this patch into smaller pieces to allow for easier inclusion into the mainline kernel.

The other available patch is Rik van Riel's rmap VM. [Earlier story] Regarding this effort, Rik says, "This is an attempt at making a more robust and flexible VM subsystem, while cleaning up a lot of code at the same time." Today he released rmap-12i, now based on Marcelo's main 2.4 kernel tree. The -rmap VM is currently included in Alan Cox's -ac patches.

Emails from both Andrea and Rik follow.

Hans Reiser recently submitted a group of 13 small patches for ReiserFS to Linus Torvalds - one of which was labled as critical, fixing a filesystem corruption issue. Specifically, that patch "Fixes a problem that was created during inode structure cleanup/ private parts separation. This fix was made by Chris Mason. This is very critical bugfix. Without it, filesystem corruption happens on savelinks processing and possibly in some other cases." Please note, this corruption only affects ReiserFS in the 2.5 development kernel.

In the same brief email, Hans stated, "We will set up a secure bitkeeper clone later this week, for now we send you old fashioned patches".

KernelTraffic #161 has been released. KernelTraffic offers a summary of the very high traffic Linux Kernel Mailing List. Anyone interested in Linux kernel development, but not having the time to sift through the lkml, will greatly appreciate KernelTraffic.