Decrease to 0 is what I've been advocating under VM. Keeps linux from doing
preemptive moves to swap. Just let VM see the page is being not used and he
will page it out.
Marcy. Sent from my BlackBerry.
----- Original Message -----
From: Linux on 390 Port <LINUX-390@vm.marist.edu>
To: LINUX-390@vm.marist.edu <LINUX-390@vm.marist.edu>
Sent: Thu Aug 05 10:32:10 2010
Subject: Re: [LINUX-390] kernel: page allocation failure recommendations
Thanks to all that responded. I appreciate everyone's responsiveness. I
increased vm.swappiness from 60 to 80. It is too early to tell if it made
any significant difference. We have also accelerated our plans to move
forward with our SLE-10-s390x-SP3 production implementation.
Peter
Shane Ginnane <sginn...@isi.com.au>
Sent by: Linux on 390 Port <LINUX-390@vm.marist.edu>
08/04/2010 10:10 PM
Please respond to
Linux on 390 Port <LINUX-390@vm.marist.edu>
To
LINUX-390@vm.marist.edu
cc
Subject
Re: kernel: page allocation failure recommendations
I quite liked this from one of the kernel devs:
<quote>
But please bear in mind, this "page allocation failure" message
is purely a developer diagnostic thing. The reason it is there
is so that if some random toaster driver oopses over a failure
to handle an allocation failure, the person who reports the bug
can say "I saw an allocation failure and then your driver crashed".
Which tells the driver developer where to look.
</quote>
Although recoverable, I'd be looking at adding storage to the guest. I
can't see swappiness helping in this context - but I don't see it harming
either, and I generally agree with the sentiment that it should be lower
in a z/ environment.
Getting up to date on the kernel would also be a good idea as Mark
suggested - lots of reports on late 2.5 and early 2.6 kernels.
Shane ...
(interestingly I don't see this post on the maillist archive)
Linux on 390 Port <LINUX-390@VM.MARIST.EDU> wrote on 05/08/2010 02:56:54
AM:
> We are running the following Linux:
>
> Linux linuxp01 2.6.5-7.315-s390x #1 SMP Wed Nov 26 13:03:18 UTC 2008
> s390x s390x s390x GNU/Linux with SLES-9-s390x-SP4 + "online updates"
> under /VM Version 5 Release 4.0, service level 0902 (64-bit). Linux
> is defined with 768MB of memory.
>
> We recently implemented CICS Transaction Gateway version 6.0.1 fix
> pack and since then are seeing some page fault errors. However, I am
> not really seeing memory shortage issues with the z/VM monitor or
> the Linux free ?m errors. I am thinking about lowering vm.swappiness
> from 60. What does everyone think, is that worth doing? Any other
> recommendations?
>
> We are limited on memory resources but if push came to shove, I
> could increase from 768MB to 1024MB and increase the swap space
accordingly.
>
> I know, I know, all this stuff is old, but we are in the process of
upgrading.
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