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Debate on Linux Virtual Memory Handling

Posted by CmdrTaco on from the stuff-to-read dept.

xturnip sent us a good piece running over at Byte about Linux's VM. Somewhat more technical then the stuff we usually see online, this one talks about different VM systems, and the egos in the kernel. Its worth a read.

3 of 330 comments (clear)

  1. OSS Power by MikeD83 · · Score: 1, Redundant

    I think this shows the power of open source software. Everyone, thought Rik's system would be great. Unfortunately it was not, so Linus used Arcangeli's new VM code. Problem solved. Stable as ever. This major OS change happened over a couple months I bet Redmond couldn't make that happen if a VM bug was found now in XP.

  2. Make it a build option by hattig · · Score: 0, Redundant
    Why not make it a build option in the kernel (along with the preemption patches and the like). A single kernel is not going to satisfy every use of an OS - Server, Multimedia, Desktop, Games, etc. VM is one thing that can change OS functionality with regards for this.

    So in a Linux Distro install it can ask you "Are you using this computer as a (a) server (b) Multimedia (c) Desktop (d) Games (e) Mixture, and then it can install an appropriate kernel for you with the appropriate VM and preemption patches. A multimedia computer would like the low latency preemption, for example...

    The linux kernel has 5 main parts. There is no reason that each part cannot be modularised away in order to get alternative functionality depending on build options and the target environment.

    Do you think that Windows 2000 DataCenter has the same VM system as Windows 2000 Professional? I severely doubt it. ANd I bet that MS' in-house kernel build tool will have VM type as a selectable option, as well as many other subsystems.

  3. Brief synopsis: by grmoc · · Score: 1, Redundant

    This article by Moshe Mar talks about the linux kernel, and especially a recent split in the community in which/whose VM to use.

    The "old" vm, the article says, had some relative impressive problems- swapoff with full memory and you could sit in front of a swap-crazy machine for 15 minutes, machines with small memory (40 MB or less) could experience sudden swap storms up to kernel 2.4.7, and the amount of swap available in the system depended on the amount of memory (as opposed to the system in 2.2 where the total memory was RAM+swap).

    The VM used in 2.4 'till 2.4.10 was written (it seems from the article) in large part by Rik Van Riel. Later Andrea Arcangeli (in Sept) wrote a whole new VM, which was accepted into the kernel. Viola, new Vm in 2.4.10.

    The article discusses that Alan Cox doesn't like the new VM as much, and has stuck with the old one. The author of the article seems to be in support of Andrea's new VM.

    The article then goes on to discuss kernel preemption- pros (low latency), cons (lower throughput/power), and on which machines such things are important (servers, vs PCs).