On Mon, Jan 13, 2020 at 11:42:57AM +0100, Christian Brauner wrote: > On Mon, Jan 13, 2020 at 11:47:11AM +0300, Kirill Tkhai wrote: < snip > > > > +SYSCALL_DEFINE5(process_madvise, int, pidfd, unsigned long, start, > > > + size_t, len_in, int, behavior, unsigned long, flags) > > > > I don't like the interface. The fact we have pidfd does not mean, > > we have to use it for new syscalls always. A user may want to set > > madvise for specific pid from console and pass pid as argument. > > pidfd would be an overkill in this case. > > We usually call "kill -9 pid" from console. Why shouldn't process_madvise() > > allow this? > > > > I suggent to extend first argument to work with both pid and pidfd. > > Look at what we have for waitid(idtype, id_t id, ...) for example: > > > > idtype == P_PID > > Wait for the child whose process ID matches id. > > > > idtype == P_PIDFD (since Linux 5.4) > > Wait for the child referred to by the PID file descriptor specified in id. (See pidfd_open(2) for further information on > > PID file descriptors.) > > > > We may use @flags argument for this. > > Sorry for chiming in just a comment. Overall, I don't particularly care > how or if you integrate pidfd here. One thing I would like to point out > is that we're working on a patch to place new features under pidfd > specific flags. This e.g. means a pidfd would be only be able to be used > for madvise operations (or getfd operations) if it was created with that > specific flag set making it easier to share them with other processes. > So if you integrate them here I would be quite thankful if you target > the patchset for the v5.7 merge window, not for v5.6. Hi Christian, Sorry but I couldn't understand your point. Could you clarify what you meant? Thanks.
