Linux memory cgroup v2: how the kernel enforces the budget

What the memory controller actually does The cgroup v2 memory controller enforces a per-cgroup memory budget that the page allocator checks at every allocation. When a cgroup exceeds its allowance, the kernel starts reclaiming its pages, slowing down its tasks under memory pressure, and — if the cgroup is at its hard limit and cannot... » read more

Linux PSI memory pressure: what it really measures

What PSI actually measures Pressure Stall Information (PSI) was merged in Linux 4.20 (commit e970d0aa0bb98a9d4b9a2e3887da44b79f7b46c8 upstream — Johannes Weiner’s psi-tracking series). It is not a load average, it is not a throughput number, and it is emphatically not a “how busy is the CPU” metric. PSI answers one question and one question only: For how... » read more