On Fri, 2009-12-04 at 01:18 -0600, Kumar Gala wrote: > Ben, David, > > If we want to support true 4G/4G split on ppc32 using the MSB of the > address to determine of the pgd_t is for hugetlbfs isn't going to > work. Since every pointer in the pgd_t -> pud_t -> pmd_t is point to > at least a 4K page I would think the low order 12-bits should always > be 0.
On 32 bit maybe. On 64, the pg/u/md's can be smaller. I don't really want to have a different encoding for both types though. > Could we use something like: > > addr[0:51] || shift [52:59] || flags [60:63] > > with the LSB flag being 'normal pointer' vs 'hugetlbfs mangled > pointer'. Seems like shift will at most be 64 so 8-bits should cover > it. Cheers, Ben. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
