On Fri, 2013-11-22 at 09:11 +1100, Paul Mackerras wrote: > On Thu, Nov 21, 2013 at 10:17:55AM +0800, Liu Ping Fan wrote: > > For 64K page, we waste half of the pte_t page. With this patch, after > > changing PGD_INDEX_SIZE from 12 to 11, PTE_INDEX_SIZE from 8 to 9, > > we can improve the usage of pte_t page and shrink the continuous phys > > size for pgd_t.
Also you did you miss that we use the second half to store the per-subpage hash info when using 64k on top of HW 4k ? Cheers, Ben. > > Signed-off-by: Liu Ping Fan <pingf...@linux.vnet.ibm.com> > > --- > > arch/powerpc/include/asm/pgtable-ppc64-64k.h | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/arch/powerpc/include/asm/pgtable-ppc64-64k.h > > b/arch/powerpc/include/asm/pgtable-ppc64-64k.h > > index a56b82f..f6955ff 100644 > > --- a/arch/powerpc/include/asm/pgtable-ppc64-64k.h > > +++ b/arch/powerpc/include/asm/pgtable-ppc64-64k.h > > @@ -4,10 +4,10 @@ > > #include <asm-generic/pgtable-nopud.h> > > > > > > -#define PTE_INDEX_SIZE 8 > > +#define PTE_INDEX_SIZE 9 > > #define PMD_INDEX_SIZE 10 > > #define PUD_INDEX_SIZE 0 > > -#define PGD_INDEX_SIZE 12 > > +#define PGD_INDEX_SIZE 11 > > Nack. Those definitions are the way they are in order to have the PMD > map 16MB, which is our large page size, so that transparent huge pages > work. > > Paul. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
