On Tue 06-08-19 18:01:50, Johannes Weiner wrote: > On Tue, Aug 06, 2019 at 09:27:05AM -0700, Suren Baghdasaryan wrote: [...] > > > > I'm not sure 10s is the perfect value here, but I do think the kernel > > > > should try to get out of such a state, where interacting with the > > > > system is impossible, within a reasonable amount of time. > > > > > > > > It could be a little too short for non-interactive number-crunching > > > > systems... > > > > > > Would it be possible to have a module with tunning knobs as parameters > > > and hook into the PSI infrastructure? People can play with the setting > > > to their need, we wouldn't really have think about the user visible API > > > for the tuning and this could be easily adopted as an opt-in mechanism > > > without a risk of regressions. > > It's relatively easy to trigger a livelock that disables the entire > system for good, as a regular user. It's a little weird to make the > bug fix for that an opt-in with an extensive configuration interface. Yes, I definitely do agree that this is a bug fix more than a feature. The thing is that we do not know what the proper default is for a wide variety of workloads so some way of configurability is needed (level and period). If making this a module would require a lot of additional code then we need a kernel command line parameter at least. A module would have a nice advantage that you can change your configuration without rebooting. The same can be achieved by a sysfs on the other hand. -- Michal Hocko SUSE Labs
