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    SubjectRe: [PATCH] nodemask_t x86_64 changes [5/7]
    > CPU_MASK_ALL ...

    Yup - now you tell me ... ;).

    I just got done figuring it out in a slightly variant way ... ('nbits'
    is NR_CPUS or similar):

    #define MASK_LAST_WORD(nbits) \
    ( \
    ((nbits) % BITS_PER_LONG) ? \
    (1<<((nbits) % BITS_PER_LONG))-1 : ~0UL \
    )

    #define MASK_ALL(nbits) \
    { { \
    [0 ... BITS_TO_LONGS(nbits)-1] = ~0UL, \
    [BITS_TO_LONGS(nbits)-1] = MASK_LAST_WORD(nbits) \
    } }

    This way overwrites the last word of the mask, first putting ~0UL
    in all words, then however many bits are needed in the last word.

    Does your way work if NR_CPUS is less than BITS_PER_LONG?
    Won't gcc complain upon seeing something like, for say
    NR_CPUS = 4 on a 32 bit system:

    { [ 0 ... -1 ] = ~0UL, ~0UL << 28 }

    with the errors and warnings:

    error: empty index range in initializer
    warning: excess elements in struct initializer

    and shouldn't the last word be inverted: ~(~0UL << NR_CPUS_UNDEF) ?

    --
    I won't rest till it's the best ...
    Programmer, Linux Scalability
    Paul Jackson <pj@sgi.com> 1.650.933.1373
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