kernel-packages team mailing list archive
Mailing list archive
[Bug 159356] Re: System freeze on high memory usage
This has annoyed me through the years on different machines and on different distributions ((K)Ubuntu and Debian).
I am here because I experienced it, once more, a few minutes ago. Hard-drive (SSDs are silent, but I could tell from the led) usage skyrocketed even though I do not have any swap partition. Mouse cursor lagged, and even Ctrl+Alt+F1 (take me to a console) or Ctrl+Alt+Backspace (terminate X) did not work. I had to hit the power button.
If I can be of any help, I will do my best. This bug is the single worst
thing in the Linux experience that I have ever had.
You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux in Ubuntu.
System freeze on high memory usage
Status in linux package in Ubuntu:
I run a batch matlab job server here at my lab, running Dapper 6.06 (for the LTS). One of the users has submitted a very memory-consuming job, which successfully crashes the server. Upon closer inspection, the crash happens like this:
1. I run matlab with the given file (as an ordinary, unpriveleged user)
2. RAM usage quickly fills up
3. Once the RAM meter hits 100%, the system freezes: All SSH connections freeze up, and while switching VTs directly on the machine works, no new processes run - so one can't log in, or do anything if he is logged in. (Sometimes typing doesn't work at all)
Note that the swap - while 7 gigs of it are available - is never used.
(The machine has 7 gigs of RAM as well)
I've tried the same on my Gutsy 32-bit box, and there was no system
freezeup - matlab simply notified that the system was out of memory.
However, it did this once memory was 100% in use - and still, swap
didn't get used at all! (Though it is mounted correctly and shows up
in "top" and "free").
So first thing's first - I'd like to eliminate the crash issue. I
suppose I could switch the server to 32-bit, but I think that would be
a performance loss, considering that it does a lot of heavy
computation. There is no reason, however, that this should happen on a
64-bit machine anyway. Why does it?
WORKAROUND: Enabling DMA in the BIOS
To manage notifications about this bug go to: