On Wed, Nov 13, 2019 at 11:02:12AM +0100, Arnd Bergmann wrote: ...
There are clearly too many time types at the moment, but I'm in the process of throwing out the ones we no longer need now.
I do have a number patches implementing other variants for the syscall, and I suppose that if we end up adding __kernel_rusage, that would have to go with a set of syscalls using 64-bit seconds/nanoseconds rather than the old 32/64 microseconds. I don't know what other changes remain that anyone would want from sys_waitid() now that it does support pidfd.
If there is still a need for a new waitid() replacement, that should take that new __kernel_rusage I think, but until then I hope we are fine with today's getrusage+waitid based on the current struct rusage.
BSD has wait6() to return separate rusage structures for 'self' and 'children', but I could not find any application (using the freebsd sources and debian code search) that actually uses that information, so there might not be any demand for that.
Thanks for detailed info Arnd!