On Mon, Apr 3, 2023 at 3:03 PM Yosry Ahmed <yosryahmed@xxxxxxxxxx> wrote: > > Currently, we approximate the root usage by adding the memcg stats for > anon, file, and conditionally swap (for memsw). To read the memcg stats > we need to invoke an rstat flush. rstat flushes can be expensive, they > scale with the number of cpus and cgroups on the system. > > mem_cgroup_usage() is called by memcg_events()->mem_cgroup_threshold() > with irqs disabled, so such an expensive operation with irqs disabled > can cause problems. > > Instead, approximate the root usage from global state. This is not 100% > accurate, but the root usage has always been ill-defined anyway. > > Signed-off-by: Yosry Ahmed <yosryahmed@xxxxxxxxxx> Acked-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
