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    SubjectRe: [PATCH] cpumask 5/10 rewrite cpumask.h - single bitmap based implementation
    Paul Jackson wrote:
    >>I don't see what you gain from having the cpumask type but having
    >>to get at its internals with the bitop functions.
    > The essential gain, in my view, of cpumask, is that it encapsulates
    > the value NR_CPUS. cpumasks are bitmaps of length NR_CPUS.
    > Yes, there is an open issue of whether cpumasks are worth it.
    > I think enough code has taken to them that they are.

    Yes, I'm all for the full cpumask abstraction.

    > The getting at internals (via cpus_addr(), I'm guessing you mean)
    > was a workaround for some code that messed with cpumasks and simple
    > unsigned longs as if they were interoperable. "cpus_addr" should
    > be marked deprecated, and its use coded out. Its remaining uses
    > are in arch-specific areas where I lack the expertise and testing
    > environment to accomplish such.
    > I needed some legacy mechanism such as this, in order to avoid
    > having such existing uses bring the entire cpumask overhaul to
    > a screeching halt.

    No, by getting at the internals, I mean the internals of the
    type itself. Its implementation, if you will. (Well I guess
    that also *includes* users getting the address and derefing it
    as an unsigned long).

    But no, I was talking about something more general. Rusty wrote:

    >>+#define cpus_addr(src) ((src).bits)
    > We've discussed this before when talking about whether it'd be easier to
    > just make people use raw bitop functions directly, so I know we have
    > philosophical differences here.
    > So, opinion alert: if I were doing this, I'd probably live without this
    > macro; in my mind it crosses the "too much abstraction" line. I did
    > momentarily wonder what this macro did when I saw it used in the
    > succeeding patches.

    Now in my opinion, it is either all or nothing. I could be wrong,
    but I don't think there is any point with a nice cpumask type if
    you are just going to get inside it and do bitmap operations on it.

    In summary, I think your patches are nice :)
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