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    SubjectRe: [PATCH][16/26] IB/mthca: mem-free doorbell record writing
    Roland Dreier wrote:
    > Add a mthca_write_db_rec() to wrap writing doorbell records. On
    > 64-bit archs, this is just a 64-bit write, while on 32-bit archs it
    > splits the write into two 32-bit writes with a memory barrier to make
    > sure the two halves of the record are written in the correct order.

    > +static inline void mthca_write_db_rec(u32 val[2], u32 *db)
    > +{
    > + db[0] = val[0];
    > + wmb();
    > + db[1] = val[1];
    > +}
    > +


    Are you concerned about ordering, or write-combining?

    I am unaware of a situation where writes are re-ordered into a reversed,
    descending order for no apparent reason.

    Jeff


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