Trivial suggestions for README.md

[trentbuck]

Please link to the Linux MM team's wiki which describes the problem and why they haven't already fixed it:

• https://linux-mm.org/AdvancedPageReplacement (and related pages on that wiki)

Also, your alternate methods shows you to do it using raw cgroups.
Please mention that systemd 231+ users can easily get the same results on a per-unit basis with MemoryHigh=.
For example,

    # my-update-script.service
    [Service]
    Type=oneshot
    Exec=/usr/local/bin/my-update-script
    MemoryHigh=128M

The exact MemoryHigh= is not important -- it should be bigger than the script's typical peak usage, and significantly lower than your total RAM.

PS: MemoryHigh= uses the second generation of cgroup stuff. IIRC your README.md is still documenting the first-generation cgroup stuff? I think the details are buried in https://www.kernel.org/doc/Documentation/cgroup-v2.txt but I haven't gone digging for a while.