Re: removing mm->rss and mm->anon_rss from kernel?

[Nick Piggin <nickpiggin@yahoo.com.au>]

Matthew Wilcox wrote:
> On Tue, Nov 09, 2004 at 01:40:20PM +1100, Nick Piggin wrote:
> 
>>I wonder if a per process flag or something could be used to turn off
>>the statistics counters? I guess statistics could still be gathered for
>>that process by using your lazy counting functions, Christoph.
> 
> 
> I don't get it.  It seems to me that any process that's going to
> experience problems with these statistics counters is going to be
> precisely the one that you want the statistics for!  What was the problem
> with per-cpu counters again?
> 

Not sure if they'd be the ones you want statistics for. If so, then
you're stuck between a rock and a hard place really. However if there
is room for compromise, then this may be a solution.

I think the problem with per-cpu counters is that it wouldn't be a
very good solution for mainline either. It would also penalise all
single threaded tasks for zero gain... quite significantly if you
did a static cacheline aligned array in the mm_struct even with
small CPU counts. Maybe less so resource wise if you used
alloc_percpu, but that would increase complexity. I don't know, maybe
it is an option.