Re: kswapd taking 100% CPU - only there's no swap?

[Don MacAskill <don smugmug com>]

Arjan van de Ven wrote:
> On Mon, 2006-03-06 at 16:27 -0800, Don MacAskill wrote:
>
> > We have an 8-way RHEL4 AS system (4 dual-core Opterons) with no swap 
> > (because swapping is still broken for DB loads.  It swaps the DB out in 
> > preference of disk cache).
>
>
> zero swap is a really bad idea. At least make a 10Mb or so swap.

Created a 10MB swap file and turned it on.  kswapd3 immediately stopped 
using 100% of a CPU and I'm seeing much more normal usage. (And only 
like 5-7MB of so of swap used, generally.  That may be because of the 
swappiness and vfs_cache_pressure settings, though...)

Thanks Arjan!

I'd still love to hear more about why it's a bad idea to have no swap, 
particularly given the number of diskless nodes we have and plan to 
deploy.  Apparently my swap knowledge is lacking.  :)

Thanks again,

Don