On 22.05.2019 18:22, Kirill A. Shutemov wrote: > On Mon, May 20, 2019 at 05:00:01PM +0300, Kirill Tkhai wrote: >> This patchset adds a new syscall, which makes possible >> to clone a VMA from a process to current process. >> The syscall supplements the functionality provided >> by process_vm_writev() and process_vm_readv() syscalls, >> and it may be useful in many situation. > > Kirill, could you explain how the change affects rmap and how it is safe. > > My concern is that the patchset allows to map the same page multiple times > within one process or even map page allocated by child to the parrent. Speaking honestly, we already support this model, since ZERO_PAGE() may be mapped multiply times in any number of mappings. Kirill
