Re: aio: questions with ioctx_alloc() and large num_possible_cpus()

From: Jeff Moyer
Date: Fri Oct 28 2016 - 15:01:24 EST


Benjamin LaHaise <bcrl@xxxxxxxxx> writes:

> Today's high end systems are tomorrow's desktops... It probably makes

Well, to some degree I agree with you. >100 processor high end systems
have been around for a long time, but we still don't have those on the
desktop. ;-)

> sense to implement per-user limits rather than the current global limit,
> and maybe even convert them to an rlimit to better fit in with the
> available frameworks for managing these things.

I actually wrote a patch to do this back in 2007:
http://www.gossamer-threads.com/lists/linux/kernel/1043934

It used the mlock rlimit. I ultimately decided to rescind it, since
there were years of experience with the current tunable, and plenty of
documentation on it, too. We could put aio-max-nr on the deprecated
path, though, if folks want to go that route. Let me know and I can
investigate resurrecting that patch. Though I would like input on
whether a new rlimit is desired.

Cheers,
Jeff