Re: [PATCH 1/4] vmscan: simplify shrink_inactive_list()

[Mel Gorman <mel@csn.ul.ie>]

On Thu, Apr 15, 2010 at 05:01:36PM +0200, Andi Kleen wrote:
> Mel Gorman <mel@csn.ul.ie> writes:
> >
> > $ stack-o-meter vmlinux-vanilla vmlinux-2-simplfy-shrink 
> > add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-144 (-144)
> > function                                     old     new   delta
> > shrink_zone                                 1232    1160     -72
> > kswapd                                       748     676     -72
> 
> And the next time someone adds a new feature to these code paths or
> the compiler inlines differently these 72 bytes are easily there
> again. It's not really a long term solution. Code is tending to get
> more complicated all the time. I consider it unlikely this trend will
> stop any time soon.
> 

The same logic applies when/if page writeback is split so that it is
handled by a separate thread.

> So just doing some stack micro optimizations doesn't really help 
> all that much.
> 

It's a buying-time venture, I'll agree but as both approaches are only
about reducing stack stack they wouldn't be long-term solutions by your
criteria. What do you suggest?


-- 
Mel Gorman
Part-time Phd Student                          Linux Technology Center
University of Limerick                         IBM Dublin Software Lab