Re: 2.6.10: kswapd spins like crazy

[Nick Piggin <nickpiggin@yahoo.com.au>]

On Thu, 2005-02-03 at 11:29 +0100, Terje Fåberg wrote:
> I recently upgraded my desktop from 2.4.28 to
> 2.6.10. Even under moderate memory pressure kswapd
> regularly eats almost all available cpu time 
> whenever there is a little more IO throughput,
> like copying large files. The system is extremely
> sluggish during this. The system load goes up to 
> 7.5 or more.
>  
> This is a Pentium3-866 with 768MB RAM, 2x1GB 
> swap partitions, vanilla 2.6.10. The strange 
> behaviour starts at about 200 MB of swap in use.
> 2.4.28 masters the same workload without any
> problems.
> 
> vmstat:
> procs -----------memory---------- 
>  r  b   swpd   free   buff  cache
>  6  1 428012   4868  33236 347184
> ---swap-- -----io---- --system-- ----cpu----
>  si   so    bi    bo   in    cs us sy id wa
>  10    7   147   120  108   111 19 10 68  3
> 
> Is there anything I can do to track this down?
> 

Can you post about 10 seconds of `vmstat 1` output
while this is happening?

Also:
`cat /proc/vmstat > pre ; sleep 10 ; cat /proc/vmstat > post`
while this is happening, and send the pre and post files.

cat /proc/meminfo also might be helpful.

And compile a kernel with "magic sysrq" support, and get a
couple of Alt+SysRq+M dumps (the output will be in dmesg).

Thanks,
Nick