On Tue, 2009-02-03 at 17:08 -0800, Roland Dreier wrote: > Forwarding Eli's patch below, since PowerPC guys may have missed it. I > guess the question for Ben et al is whether there is any issue with > exporting HPAGE_SHIFT for modules (can be EXPORT_SYMBOL_GPL if you feel > it's an internal detail). It would probably make sense to roll this > change into the mlx4 change that Eli alludes to below and merge through > my tree (with ppc maintainer acks of course), rather than splitting this > patch out and introducing cross-tree dependencies (and also separating > the rationale for the change from the change itself). > > Thanks, > Roland > > > Drivers may want to take advantage of the large pages used for memory obtained > from hugetlbfs. One example is mlx4_ib which can use much less MTT entries (in > the order of HPAGE_SIZE / PAGE_SIZE) when registering such memory, thus scale > significantly better when registering larger memory regions. Other drivers > could also benefit from this.
Except that we support multiple large page sizes nowadays ... I think the size can be specified per mountpoint of hugetlbfs no ? Thus things like mellanox would have to query the page size used for a given mapping. Do the generic hugetlbfs code provides such an API ? If not, we may need to add one. Cheers, Ben. > Signed-off-by: Eli Cohen <e...@mellanox.co.il> > --- > arch/powerpc/mm/hash_utils_64.c | 1 + > 1 files changed, 1 insertions(+), 0 deletions(-) > > diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c > index 8d5b475..6cff8c7 100644 > --- a/arch/powerpc/mm/hash_utils_64.c > +++ b/arch/powerpc/mm/hash_utils_64.c > @@ -104,6 +104,7 @@ int mmu_highuser_ssize = MMU_SEGSIZE_256M; > u16 mmu_slb_size = 64; > #ifdef CONFIG_HUGETLB_PAGE > unsigned int HPAGE_SHIFT; > +EXPORT_SYMBOL(HPAGE_SHIFT); > #endif > #ifdef CONFIG_PPC_64K_PAGES > int mmu_ci_restrictions; _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
