[PATCH] psi: reduce min window size to 50ms

[Michal Hocko]

On Tue 14-02-23 11:34:30, Suren Baghdasaryan wrote:
[...]
> Your suggestion to have this limit configurable sounds like obvious
> solution. I would like to get some opinions from other maintainers.
> Johannes, WDYT? CC'ing Michal to chime in as well since this is mostly
> related to memory stalls.

I do not think that making this configurable helps much. Many users will
be bound to distribution config and also it would be hard to experiment
with a recompile cycle every time. This seems just too impractical.

Is there any reason why we shouldn't allow any timeout? Shorter
timeouts could be restricted to a priviledged context to avoid an easy
way to swamp system by too frequent polling.

Btw. it seems that there is is only a limit on a single trigger per fd
but no limits per user so it doesn't sound too hard to end up with too
much polling even with a larger timeouts. To me it seems like we need to
contain the polling thread to be bound by the cpu controller.
-- 
Michal Hocko
SUSE Labs