On 4/15/19 11:09 AM, Feng Li wrote: > Hi Jens, > > I'm interested in the io_uring, and have a doubt about it. > If I setup io_uring with IORING_REGISTER_BUFFERS, > the kernel doesn't need copy data from user space to the kernel, right? > Does it mean this is a zero-copy feature? Doesn't it depends on the definition of 'copy'? There is still a copy from original userspace pages to the registered buffer? Dongli Zhang > > From the code, kernel directly get the userspace virtual address's > pages and store them: > > 2475 pret = get_user_pages_longterm(ubuf, nr_pages, FOLL_WRITE, > 2476 pages, vmas); > > >
