On Thu, Jul 25, 2013 at 12:29 AM, Pavel Emelyanov <xemul@xxxxxxxxxxxxx> wrote: > On 07/24/2013 11:40 PM, Andy Lutomirski wrote: >> On Wed, Jul 24, 2013 at 12:04 PM, Cyrill Gorcunov <gorcunov@xxxxxxxxx> wrote: >>> On Wed, Jul 24, 2013 at 10:55:41PM +0400, Pavel Emelyanov wrote: >>>>> > >> Perhaps another bit should be allocated to expose to userspace either >> "soft-dirty", "soft-clean", or "soft-dirty unsupported"? >> >> There's another possible issue with private file-backed pages, though: >> how do you distinguish clean-and-not-cowed from cowed-but-soft-clean? >> (The former will reflect changes in the underlying file, I think, but >> the latter won't.) > > There's a bit called PAGE_FILE bit in /proc/pagemap file introduced with > the 052fb0d635df5d49dfc85687d94e1a87bf09378d commit. > > Plz, refer to Documentation/vm/pagemap.txt and soft-dirty.txt, all this > is described there pretty well. > Fair enough. I'm still a little bit concerned that it will be hard for userspace to distinguish between things for which soft-dirty works (which will be more things once the patches are in) and things for which soft-dirty doesn't work, assuming any are left. But maybe this is silly. --Andy -- 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>