Re: [patch 2/2] MM: allow per-cpu vmstat_threshold and vmstat_worker configuration

[Rik van Riel]

On Tue, 2017-04-25 at 10:57 -0300, Marcelo Tosatti wrote:
> The per-CPU vmstat worker is a problem on -RT workloads (because
> ideally the CPU is entirely reserved for the -RT app, without
> interference). The worker transfers accumulated per-CPUÂ
> vmstat counters to global counters.
> 
> To resolve the problem, create two tunables:
> 
> * Userspace configurable per-CPU vmstat threshold: by default theÂ
> VM code calculates the size of the per-CPU vmstat arrays. ThisÂ
> tunable allows userspace to configure the values.
> 
> * Userspace configurable per-CPU vmstat worker: allow disabling
> the per-CPU vmstat worker.
> 
> The patch below contains documentation which describes the tunables
> in more detail.

The documentation says what the tunables do, but
not how you should set them in different scenarios,
or why.

That could be a little more helpful to sysadmins.