On Thu, Apr 30, 2015 at 04:11:30PM +0300, Konstantin Khlebnikov wrote: > On Thu, Apr 30, 2015 at 2:43 PM, Konstantin Khlebnikov <koct9i@xxxxxxxxx> wrote: > > On Thu, Apr 30, 2015 at 12:02 AM, Linus Torvalds > > <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > >> On Wed, Apr 29, 2015 at 1:44 PM, Konstantin Khlebnikov <koct9i@xxxxxxxxx> wrote: > >>> > >>> This's no longer true. After recent fixes for "anon_vma endless growing" new vma > >>> might reuse old anon_vma from grandparent vma. > >> > >> Oh well. I guess that was too simple. > >> > >> If Mark is ok with the rule that "it's not reliably if you have two > >> nested forks" (ie it only works if you exec for every fork you do), it > >> should still work, right? It sounds like Mark doesn't necessarily need > >> to handle the *generic* case. > > > > What about exposing shared/exclusive bit in pagemap == 1 if > > page_mapcount() > 1, otherwise 0 (or vise versa). > > > > Seems like this should work for detecting CoWed pages in child mm. > > Something like this (see patch in attachment) THP is not covered. Any comments on kcmp() idea? -- Kirill A. Shutemov -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
