4KSTACKS et al...

Paul subsolar at subsolar.com
Fri Aug 5 03:27:43 UTC 2005


On Thu, 2005-08-04 at 21:43 -0400, Dave Jones wrote:
> On Fri, Aug 05, 2005 at 09:22:55AM +0800, Ian Kent wrote:
>  > I also find it hard to understand why it is such a problem having a larger 
>  > stack. As you point out, as software evolves it ultimately becomes more 
>  > complex. If the developers design needs it and the software is reliable 
>  > and efficient (aka performs well) then why not.
>  > 
>  > A quick caclulation.
>  > 
>  > 2000*4k is about 8M in say 1G at least.
>  > 
>  > Not a large percentage overhead I think.
> 
> Now try finding 2000 _contiguous_ pairs of pages after the machine
> has been up for a while, under load.  Memory fragmentation makes
> this a really nasty problem, and the VM eats its own head after
> repeatedly scanning every page in the system.

I thought I heard that there was some work being done in the upstream
kernel to have a process "defrag" memory in the background.  This would
help alleviate this problem on systems with long up-times.

Paul





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