Re: Help Resource Counters Scale Better (v3)

KAMEZAWA Hiroyuki
2009-08-10T00:45:35Z

On Mon, 10 Aug 2009 09:32:29 +0900
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:

> 1. you use res_counter_read_positive() in force_empty. It seems force_empty can
> go into infinite loop. plz check. (especially when some pages are freed or swapped-in
> in other cpu while force_empry runs.)
>
> 2. In near future, we'll see 256 or 1024 cpus on a system, anyway.
> Assume 1024cpu system, 64k*1024=64M is a tolerance.
> Can't we calculate max-tolerane as following ?
>
> tolerance = min(64k * num_online_cpus(), limit_in_bytes/100);
> tolerance /= num_online_cpus();
> per_cpu_tolerance = min(16k, tolelance);
>
> I think automatic runtine adjusting of tolerance will be finally necessary,
> but above will not be very bad because we can guarantee 1% tolerance.
>

Sorry, one more.

3. As I requested when you pushed softlimit changes to mmotom, plz consider
to implement a way to check-and-notify gadget to res_counter.
See: http://marc.info/?l=linux-mm&m=124753058921677&w=2

Thanks,
-Kame