Re: CVS commit: src/sys/kern

[Robert Elz <kre%munnari.OZ.AU@localhost>]

    Date:        Sun, 5 May 2019 16:38:04 -0400
    From:        Christos Zoulas <christos%zoulas.com@localhost>
    Message-ID:  <41FB59A5-C9E0-4392-BD5C-508E5B80E572%zoulas.com@localhost>

  | I did not want to make it smaller, but yes,
  | you are right I will remove the slop.
  |
  | > On May 5, 2019, at 4:30 PM, matthew green <mrg%eterna.com.au@localhost> wrote:

  | > is the old value useful now?  i think your checking against
  | > the current limit seems totally valid and obsoletes the old
  | > check which was simply some slop over open fds.

It might matter in a case where a process has lots open files and
then sets its limit lower (and yes, I have done that while testing
that EMFILE errors get handled correctly...)  In such a case it
might want to poll more files than the limit allows.

I also don't believe there's any restriction on including the same
fd more than once (with diffent bits set in events probably) - perhaps
might happen in threaded code when one thread is reading from an fd,
and a diffenent one is writing to it (probably a net connection or tty).

What would probably be more useful would be to remove the limit, or
simply set a reasonable one, and document it.   Its relationship to
open file counts is nebulous at best.

kre