Re: Memory Problem in 2.4.9 ?

[Stephan von Krawczynski <skraw@ithnet.com>]

On Tue, 21 Aug 2001 21:10:44 +0200
Daniel Phillips <phillips@bonn-fries.net> wrote:

> > Aug 21 20:14:51 admin kernel: __alloc_pages: 3-order allocation failed 
> (gfp=0x20/0).
> > Aug 21 20:14:51 admin last message repeated 146 times
> > 
> > Next idea?
> 
> It's an atomic allocation, the driver is supposed to be able to handle this, 
> and it does since you report that the burn just runs slowly, it does not 
> stop.  There is way too much in cache:
> 
> >         total:    used:    free:  shared: buffers:  cached:
> > Mem:  1053675520 1047502848  6172672        0 20930560 939307008
> > Swap: 271392768 15880192 255512576
> 
> This is causing the high order allocation failures - with only a small 
> fraction of memory free the chances of none of it being in contiguous, 
> aligned 8 page units rises dramatically.

I basically thought the same. In fact I do not understand why. Are there any parameters tunable to balance the whole picture a bit more towards the free pages?

>  It's likely the kprint that is 
> slowing you down, you could check this by commenting it out (page_alloc.c, 
> near the end of __alloc_pages).

I guess you mean the formerly patched debug-output, do you? I commented it out and saw a way better result than before. In fact I did not manage to break the NFS-copy at all, and although I managed to get the cpu load up to about 5 everything worked smoother. Only now and then were some moments where the display freezes "a bit", but mouse movement continues to work.
Anyway I am not sure, if it is intended that my browser gets swapped out only by copying files via NFS which are alltogether smaller than my physical 1 GB of RAM. I do think that there is still a little too much caching going on.

> Do you have the same problem on 2.4.8, but not in 2.4.7?

I am going to check that tomorrow. Downgrading is a bit tricky on this system.

Thanks Daniel, 
I'll be back
:-)