View source for Page allocation failure. order:0, mode:0x20

[[Category:Linux]]

= page allocation failure. order:0, mode:0x20 =
If you constantly get errors like the above and stuff like:

<pre>
java: page allocation failure. order:0, mode:0x20
</pre>
instead of java: insert any random application.

Try having a look the 
<pre>
/proc/sys/vm/min_free_kbytes
</pre> 

value.

It is the min. value of free memory the kernel will reserve for itself doing sudden [heavy] swapping (more info here: http://www.kernel.org/doc/Documentation/sysctl/vm.txt )

In our system, a 24gb 8-core intel xeon monster with SAN-disks we were getting this multiple times a day usually killing a random java thread. Sometimes another random program would be terminated though.

Eventually we adjusted the value from 20000 -> 64000 and the errors went away.

You can use
<pre>
slabtop
</pre>

to get an idea about actual kernel memory usage/distribution.