Re: VM Problems in 2.6.7 (Too active OOM Killer)

From: Andrea Arcangeli
Date: Tue Jul 13 2004 - 23:11:43 EST


On Tue, Jul 13, 2004 at 08:44:02PM -0700, Peter Zaitsev wrote:
> The reason for me to disable swap both in 2.4 and 2.6 is - it really
> hurts performance. In some cases performance can be 2-3 times slower
> with swap file enabled. Using O_DIRECT and mlock() for buffers helps
> but not completely.

in 2.4 you can disable swap just fine (with oom killer disabled). until
I/somebody fix 2.6 you can workaround this problem while still avoiding
to swap much by setting /proc/sys/vm/swappiness to 0 or similar to tell
the VM "please don't swap" even if swap is enabled ;). That will still
prevent the oom killer to kick in. The oom killer is forbidden to run
as long as `free` tells you that >= 4k of swap are still available to the
OS. There are no other fundamental vm problems left I'm aware of in
latest 2.6 besides these no-swap and oom issues.
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