[9fans] cpu server and swap

[9fans] cpu server and swap

[Matthias Teege]

Moin,

Today I found my (diskless) cpu/auth server with the message

fs killed because no swap configured no physical memory

Ok, I understand but what eats the memory? The machine has 256MB
RAM and reports at startup 2387 free pages, 9548kbytes, 167948k
swap. I run a vmware cpu server with only 64MB RAM without any
problems and stats shows only 10% memory usage. As I understand
cpurc correct, cpu servers don't use swap.

What do I missing?
Matthias

--
Matthias Teege -- http://www.mteege.de
make world not war

Re: [9fans] cpu server and swap

[Geoff Collyer]

cpu servers can indeed swap, just as terminals can.  Only Ken's
original file server kernel won't swap.  Terminals are sometimes
configured to swap into /n/other/swap (in order to run them diskless
or at least real-disk-less).  They can also be configured to swap to
local disk, if present.

It looks like something is wrong; my terminal also has 256MB and I
give 55% to the kernel, primarily for images (it may be overkill, but
I use a lot of windows and hate running out of image memory at
inconvenient times), yet have lots of free memory:

	; cat /dev/swap
	4404/29266 memory 0/99066 swap

I almost never swap, but the first two numbers at least are in units
of the machine's page size (4K on the x86).  So I've got 117,064KB
(114.3MB) of non-kernel memory, of which 17,616KB (17.2MB) is in use.

You can ignore the `167948k swap', but it appears that your kernel is
only seeing about 16MB of RAM, and leaving you with 2387 pages (9548K
bytes) or about 60% of 16MB.  Try `cat /dev/swap' on that machine.  Is
there a `*maxmem=' line in your plan9.ini?  If not, it would seem that
your machine is odd enough that kernel memory sizing is getting
confused.

Re: [9fans] cpu server and swap

[mirtchov]

> fs killed because no swap configured no physical memory
>

for what it's worth, you get that message when you type '^T^Tk' on the
console of a Plan 9 machine (the process killed may be different)..

Re: [9fans] cpu server and swap

[Matthias Teege]

Geoff Collyer <geoff@collyer.net> writes:

> You can ignore the `167948k swap', but it appears that your kernel is
> only seeing about 16MB of RAM, and leaving you with 2387 pages (9548K
> bytes) or about 60% of 16MB.  Try `cat /dev/swap' on that machine.  Is
> there a `*maxmem=' line in your plan9.ini?  If not, it would seem that
> your machine is odd enough that kernel memory sizing is getting
> confused.

It looks like that. After boot the cpu server cat /dev/swap gives me
544/2378 memory, 0/39600 swap and maxmem isn't set. Oooaahhh ?%#$!
How do I tell Santa Claus that I need another cpu server?

Vielen Dank
Matthias

--
Matthias Teege -- http://www.mteege.de
make world not war

Re: [9fans] cpu server and swap

[Geoff Collyer]

You might try setting

*maxmem=268435456

in plan9.ini, and also recompile /sys/src/9/pc/memory.c
after changing /sys/src/9/pc/memory.c:12 to

#define MEMDEBUG 1

then rebuild 9pccpu and boot that kernel on your cpu server.

Re: [9fans] cpu server and swap

[ron minnich]

just a tidbit, I do know that the plan 9 memory sizing algorithm will fail
badly with some chipsets.

I doubt this is your problem, it's just interesting.

ron