This patch creates a knob to help users that have workloads suffering
from the
fix 1:1 active inactive ratio brought into the kernel by "56e49d21
vmscan:
evict use-once pages first".
It also provides the tuning mechanisms for other users that want an
even bigger
working set to be protected.
We certainly need no knob. because typical desktop users use various
application,
various workload. then, the knob doesn't help them.
Briefly - We had discussed non desktop scenarios where like a day load
that builds up the working set to 50% and a nightly backup job which
then is unable to use that protected 50% when sequentially reading a lot
of disks and due to that doesn't finish before morning.
I personally just don't feel too good knowing that 50% of my memory
might hang around unused for many hours while they could be of some use.
I absolutely agree with the old intention and see how the patch helped
with the latency issue Elladan brought up in the past - but it just
looks way too aggressive to protect it "forever" for some server use cases.