On Tue, Sep 01, 2020 at 06:23:10PM +0200, Oleg Nesterov wrote: > On 08/31, Christian Brauner wrote: > > > > --- /dev/null > > +++ b/include/uapi/linux/pidfd.h > > @@ -0,0 +1,12 @@ > > +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ > > + > > +#ifndef _UAPI_LINUX_PIDFD_H > > +#define _UAPI_LINUX_PIDFD_H > > + > > +#include <linux/types.h> > > +#include <linux/fcntl.h> > > + > > +/* Flags for pidfd_open(). */ > > +#define PIDFD_NONBLOCK O_NONBLOCK > > + > > +#endif /* _UAPI_LINUX_PIDFD_H */ > > Why? Can't we simply use O_NONBLOCK ? It's the same thing we seem to do for any other (anon inode) fds: include/linux/eventfd.h:#define EFD_NONBLOCK O_NONBLOCK include/uapi/linux/inotify.h:#define IN_NONBLOCK O_NONBLOCK include/uapi/linux/signalfd.h:#define SFD_NONBLOCK O_NONBLOCK include/uapi/linux/timerfd.h:#define TFD_NONBLOCK O_NONBLOCK also for O_CLOEXEC: include/linux/eventfd.h:#define EFD_CLOEXEC O_CLOEXEC include/linux/userfaultfd_k.h:#define UFFD_CLOEXEC O_CLOEXEC include/uapi/linux/eventpoll.h:#define EPOLL_CLOEXEC O_CLOEXEC include/uapi/linux/mount.h:#define OPEN_TREE_CLOEXEC O_CLOEXEC include/uapi/linux/perf_event.h:#define PERF_FLAG_FD_CLOEXEC (1UL << 3) /* O_CLOEXEC */ include/uapi/linux/signalfd.h:#define SFD_CLOEXEC O_CLOEXEC include/uapi/linux/timerfd.h:#define TFD_CLOEXEC O_CLOEXEC So I think we should just do the same. A clean flag namespace seems nicer to me too tbh. Christian