When system is under heavy memory pressure the system might be able
to keep free memory above the min watermark avoiding perceptible app
kills. In such situation system might end up using all its cpu
capacity on memory reclaim and not doing productive work. To detect
this condition, check memory full stall and compare it with the new
ro.lmk.stall_limit_critical tunable representing the stall threshold.
When the recorded level is over ro.lmk.stall_limit_critical, lmkd will
be allowed to kill perceptible apps. ro.lmk.stall_limit_critical
represents the max memory full stall in % that is allowed before
perceptible apps will get killed. By default it is set to 100%, which
effectively disables the feature.
Currently system stall is measured based on psi memory stall 10s average
value, however this definition might change in the future if better
metrics are developed. Setting ro.lmk.stall_limit_critical to 5 means
the system should be fully stalled (no productive work is done) for 5%
of the 10sec period, resulting in 0.5 sec loss due to the stall.
Bug: 205182133
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Change-Id: I9713e30d82641d86d1b7edb5e1ba2971b935c898
New library to create, register and destroy PSI monitors in a consistent
way with lmkd.
Test: used within lmkd
Bug: 111308141
Change-Id: If243a97f178e90fe41e2de90c7b858ba82440279
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Suren Baghdasaryan
Tim Murray