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    SubjectRe: [PATCH] Document huge memory/cache overhead of memory controller in Kconfig
    >>>>> "Jan" == Jan Engelhardt <jengelh@computergmbh.de> writes:

    Jan> On Feb 20 2008 20:50, Balbir Singh wrote:
    >> John Stoffel wrote:
    >>> I know this is a pedantic comment, but why the heck is it called such
    >>> a generic term as "Memory Controller" which doesn't give any
    >>> indication of what it does.
    >>>
    >>> Shouldn't it be something like "Memory Quota Controller", or "Memory
    >>> Limits Controller"?
    >>
    >> It's called the memory controller since it controls the amount of
    >> memory that a user can allocate (via limits). The generic term for
    >> any resource manager plugged into cgroups is a controller.

    Jan> For ordinary desktop people, memory controller is what developers
    Jan> know as MMU or sometimes even some other mysterious piece of
    Jan> silicon inside the heavy box.

    That's what was confusing me at first. I was wondering why we needed
    a memory controller when we already had one in Linux!

    Also, controlling a resource is more a matter of limits or quotas, not
    controls. Well, I'll actually back off on that, since controls does
    have a history in other industries.

    But for computers, limits is an expected and understood term, and for
    filesystems it's quotas. So in this case, I *still* think you should
    be using the term "Memory Quota Controller" instead. It just makes it
    clearer to a larger audience what you mean.

    >> If you look through some of the references in the document, we've
    >> listed our plans to support other categories of memory as well.
    >> Hence it's called a memory controller
    >>
    >>> Also, the Kconfig name "CGROUP_MEM_CONT" is just wrong, it should
    >>> be "CGROUP_MEM_CONTROLLER", just spell it out so it's clear what's
    >>> up.

    >> This has some history as well. Control groups was called containers
    >> earlier. That way a name like CGROUP_MEM_CONT could stand for
    >> cgroup memory container or cgroup memory controller.

    Jan> CONT is shorthand for "continue" ;-) (SIGCONT, f.ex.), ctrl or
    Jan> ctrlr it is for controllers (comes from Solaris iirc.)

    Right, CTLR would be more regular shorthand for CONTROLLER.

    Basically, I think you're overloading a commonly used term for your
    own uses and when it's exposed to regular users, it will cause
    confusion.

    Thanks,
    John


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