Hi David, On Tue, Sep 15, 2015 at 07:01:57PM +0100, David Woods wrote: > The arm64 MMU supports a Contiguous bit which is a hint that the TTE > is one of a set of contiguous entries which can be cached in a single > TLB entry. Supporting this bit adds new intermediate huge page sizes. > > The set of huge page sizes available depends on the base page size. > Without using contiguous pages the huge page sizes are as follows. > > 4KB: 2MB 1GB > 64KB: 512MB 4TB > > With 4KB pages, the contiguous bit groups together sets of 16 pages > and with 64KB pages it groups sets of 32 pages. This enables two new > huge page sizes in each case, so that the full set of available sizes > is as follows. > > 4KB: 64KB 2MB 32MB 1GB > 64KB: 2MB 512MB 16GB 4TB > > If the base page size is set to 64KB then 2MB pages are enabled by > default. It is possible in the future to make 2MB the default huge > page size for both 4KB and 64KB pages. > > Signed-off-by: David Woods <dwoods@xxxxxxxxxx> > Reviewed-by: Chris Metcalf <cmetcalf@xxxxxxxxxx> > --- > arch/arm64/Kconfig | 3 - > arch/arm64/include/asm/hugetlb.h | 4 + > arch/arm64/include/asm/pgtable-hwdef.h | 15 +++ > arch/arm64/include/asm/pgtable.h | 30 +++++- > arch/arm64/mm/hugetlbpage.c | 165 ++++++++++++++++++++++++++++++++- > 5 files changed, 210 insertions(+), 7 deletions(-) I glanced briefly at this, and I think you'll need to do some extra work for the CONFIG_HW_AFDBM=y case, where the CPU can set access/dirty bits in any (i.e. not necessarily all) of the page table entries in a contiguous mapping. In this case, things like huge_pte_dirty might need overriding. Will -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>