On Fri, Aug 25, 2017 at 04:19:19PM +0000, Helge Deller wrote: > On 25.08.2017 18:16, Kirill A. Shutemov wrote: > > On Fri, Aug 25, 2017 at 09:02:36AM -0700, Christoph Hellwig wrote: > >> On Fri, Aug 25, 2017 at 06:58:03PM +0300, Kirill A. Shutemov wrote: > >>> Not all archs are ready for this: > >>> > >>> arch/parisc/include/uapi/asm/mman.h:#define MAP_TYPE 0x03 /* Mask for type of mapping */ > >>> arch/parisc/include/uapi/asm/mman.h:#define MAP_FIXED 0x04 /* Interpret addr exactly */ > >> > >> I'd be happy to say that we should not care about parisc for > >> persistent memory. We'll just have to find a way to exclude > >> parisc without making life too ugly. > > > > I don't think creapling mmap() interface for one arch is the right way to > > go. I think the interface should be universal. > > > > I may imagine MAP_DIRECT can be useful not only for persistent memory. > > For tmpfs instead of mlock()? > > On parisc we have > #define MAP_SHARED 0x01 /* Share changes */ > #define MAP_PRIVATE 0x02 /* Changes are private */ > #define MAP_TYPE 0x03 /* Mask for type of mapping */ > #define MAP_FIXED 0x04 /* Interpret addr exactly */ > #define MAP_ANONYMOUS 0x10 /* don't use a file */ > > So, if you need a MAP_DIRECT, wouldn't e.g. > #define MAP_DIRECT 0x08 > be possible (for parisc, and others 0x04). > And if MAP_TYPE needs to include this flag on parisc: > #define MAP_TYPE (0x03 | 0x08) /* Mask for type of mapping */ I guess it's better to re-define MAP_TYPE as 0x3 everywhere and make MAP_DIRECT a normal flag. It's not new type of mapping anyway. -- Kirill A. Shutemov
