On Thu, Jul 12, 2018 at 04:45:37PM -0700, Andrew Morton wrote: > On Thu, 12 Jul 2018 13:29:42 -0400 Johannes Weiner <hannes@xxxxxxxxxxx> wrote: > > > Right now, psi reports pressure and stall times of already concluded > > stall events. For most use cases this is current enough, but certain > > highly latency-sensitive applications, like the Android OOM killer, > > might want to know about and react to stall states before they have > > even concluded (e.g. a prolonged reclaim cycle). > > > > This patches the procfs/cgroupfs interface such that when the pressure > > metrics are read, the current per-cpu states, if any, are taken into > > account as well. > > > > Any ongoing states are concluded, their time snapshotted, and then > > restarted. This requires holding the rq lock to avoid corruption. It > > could use some form of rq lock ratelimiting or avoidance. > > > > Requested-by: Suren Baghdasaryan <surenb@xxxxxxxxxx> > > Not-yet-signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx> > > What-does-that-mean:? I didn't think this patch was ready for upstream yet, hence the RFC and the lack of a proper sign-off. But Suren has been testing this and found it useful in his specific low-latency application, so I included it for completeness, for other testers to find, and for possible suggestions on how to improve it.
