lkml.org 
[lkml]   [2003]   [Apr]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: Reduce struct page by 8 bytes on 64bit
    On Wed, Apr 16, 2003 at 05:45:21AM -0700, David S. Miller wrote:
    > From: Andi Kleen <ak@muc.de>
    > Date: Tue, 15 Apr 2003 13:24:30 +0200
    >
    > I worked around this by declaring a new data type atomic_bitmask32
    > with matching set_bit32/clear_bit32 etc. interfaces. Currently only
    > on x86-64 aomitc_bitmask32 is defined to unsigned, everybody else
    > still uses unsigned long. The other 64bit architectures can define it to
    > unsigned too if they can confirm that it's ok to do.
    >
    > I have no problem with this.
    >
    > If you are clever, you can define a generic version even for the
    > "unsigned long" 64-bit platforms. It's left as an exercise to
    > the reader :-)

    Why is any new macro needed?

    struct page
    {
    #if BITS_PER_LONG == 64 && defined __BIG_ENDIAN
    union {
    unsigned long flags;
    atomic_t count;
    };
    #elif BITS_PER_LONG == 64 && defined __LITTLE_ENDIAN
    union {
    unsigned long flags;
    struct {
    int : 32;
    atomic_t count;
    };
    };
    #else
    unsigned long flags;
    atomic_t count;
    #endif
    ...
    };

    should do the job.

    Jakub
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2005-03-22 13:34    [W:0.020 / U:33.660 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site