On 2022/8/15 21:23, Michal Koutný wrote:

On Wed, Aug 10, 2022 at 11:25:07AM -0400, Johannes Weiner [off-list ref] wrote:

quoted

cgroup.pressure.enable sounds good to me too. Or, because it's
default-enabled and that likely won't change, cgroup.pressure.disable.

Will it not change?

I'd say that user would be interested in particular level or even just
level in subtree for PSI, so the opt-out may result in lots of explicit
disablements (or even watch for cgroups created and disable PSI there)
to get some performance back.

I have two suggestions based on the above:
1) Make the default globally configurable (mount option?)
2) Allow implicit enablement upon trigger creation

I think suggestion 1) make sense in some use case, like make per-cgroup
PSI disabled by default using a mount option, then enable using the
"cgroup.pressure" interface.

But suggestion 2) auto enable upon trigger creation, if we hide the
{cpu,memory,io}.pressure files when disabled, how can we create trigger?

Want to see what do Johannes and Tejun think about these suggestions?

Thanks.