Re: [PATCH 1/3] clean up setup_per_zone_pages_min

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

On Wed, May 20, 2009 at 06:58:03PM +0900, Minchan Kim wrote:
> Hi, Mel. 
> 
> On Wed, 20 May 2009 09:54:16 +0100
> Mel Gorman <mel@csn.ul.ie> wrote:
> 
> > On Wed, May 20, 2009 at 04:18:53PM +0900, Minchan Kim wrote:
> > > 
> > > Mel changed zone->pages_[high/low/min] with zone->watermark array.
> > > So, setup_per_zone_pages_min also have to be changed.
> > > 
> > 
> > Just to be clear, this is a function renaming to match the new zone
> > field name, not something I missed. As the function changes min, low and
> > max, a better name might have been setup_per_zone_watermarks but whether
> 
> At first, I thouht, too. But It's handle of min_free_kbytes.
> Documentation said, it's to compute a watermark[WMARK_MIN]. 
> I think many people already used that knob to contorl pages_min to keep the 
> low pages. 

Which documentation?

I'm looking at the function comment and see

 * setup_per_zone_pages_min - called when min_free_kbytes changes.
 *
 * Ensures that the pages_{min,low,high} values for each zone are set
 * correctly with respect to min_free_kbytes.

So, the values of all the watermarks are updated by that function depending
on what the new value of min_free_kbytes is. It is a bit wrong I suppose as
it missed memory hot-add

setup_per_zone_pages_min - called when min_free_kbytes changes or when memory is hot-added

> 
> So, I determined function name is proper now. 
> If setup_per_zone_watermark is better than it, we also have to change with 
> documentation. 
> 
> > you go with that name or not, this is better than what is there so;
> > 
> > Acked-by: Mel Gorman <mel@csn.ul.ie>
> 
> 
> -- 
> Kinds Regards
> Minchan Kim
> 

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