page allocation failure - am I running out of memory?

Question

Lately I've noticing entries like this one in the kern.log of one of my servers:

Feb 16 00:24:05 aramis kernel: swapper: page allocation failure. order:0, mode:0x20

This is what I'd like to know:

1. What exactly does that message mean?
2. Is my server running out of memory?

The swap usage is quite low (less than 10%), and so far I haven't noticed any processes being killed because of lack of memory.

Additional information:

• The server is a Xen instance (DomU) running Debian 6.0
• It has 512 MB of RAM and a 512 MB swap partition
• CPU load inside the virtual machine shows an average of 0.25

Answer 1

Quick google has returned this: http://www.cyberciti.biz/faq/linux-page-allocation-failure-erro/

Which appears to answer your question.

Hope this helps.