RE: RSS accounting (was: Re: 2.6.19-rc1-mm1)

["Chen, Kenneth W" <kenneth.w.chen@intel.com>]

Arjan van de Ven wrote on Wednesday, October 11, 2006 6:55 AM
> > Well I tried to defined it in terms of what you can use it for.
> > 
> > I would define the resident set size as the total number of bytes
> > of physical RAM that a process (or set of processes) is using,
> > irrespective of the rest of the system.  
> > 
> > So I think the counting should be primarily about what is mapped into
> > the page tables.  But other things can be added as is appropriate or
> > easy.
> > 
> > The practical effect should be that an application that needs more
> > pages than it's specified RSS to avoid thrashing should thrash but
> > it shouldn't take the rest of the system with it.
> 
> 
> so by your definition, hugepages are part of RSS.
> 
> Ken: what is your definition of RSS ?

I'm more inclined to define RSS as "how much ram does my application
cause to be used".  To monitor process's working set size, We already
have /proc/<pid>/smaps.  Whether we can use working set size in an
intelligent way in mm is an interesting question. Though, so far such
accounting is not utilized at all.

- Ken