Quoting r. Gleb Natapov <[EMAIL PROTECTED]>: > Subject: Re: [openib-general] Re: Re: madvise MADV_DONTFORK/MADV_DOFORK > > On Mon, Mar 13, 2006 at 05:14:20PM +0200, Michael S. Tsirkin wrote: > > > > My current thinking then goes vaguely along the lines of: > > > > > > > > We need a way to distinguish the parent from child on COW. A flag in > > > > the VMA > > > > will do it. > > > > > > > And what if child forks ones more? > > > > If COW is already set, we don't set this new flag in VMA. > > When the driver does get_user_pages with child's mm, this will break COW > > so no problem. > > > So we should check each page in VMA for COW? Is it enough to check one > page or should we check all of them? And what if VMA is a > privately mapped file? I think COW will be set on mapped pages. > > I should think about this some more.
No, the flag is per-VMA, not per-page. get_user_pages already breaks COW, we don't have to touch it at all. -- Michael S. Tsirkin Staff Engineer, Mellanox Technologies _______________________________________________ openib-general mailing list [email protected] http://openib.org/mailman/listinfo/openib-general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
