Re: Unifying epoll,aio,futexes etc. (What I really want from epoll)

From: Jamie Lokier (lk@tantalophile.demon.co.uk)
Date: Thu Oct 31 2002 - 23:59:22 EST

Mark Mielke wrote:
> On Thu, Oct 31, 2002 at 11:02:15PM +0000, Jamie Lokier wrote:
> > The semantics for this are a bit confusing and inconsistent with
> > poll(). User gets POLL_RDNORM event which means something in the
> > directory has changed, not that the directory is now readable or that
> > poll() would return POLL_RDNORM. It really should be a different
> > flag, made for the purpose.
>
> Don't be encouraging any of us to expect the ability to poll() for changes
> to regular files (log file parsers that sit on EOF periodically polling for
> further data...).

Actually you can already do something similar, if a little coarse
grained, in 2.4 kernels using dnotify on the parent directory.

> Just get *something* decent out so that we can play with it in a
> production environment. I would put off extensions such as this
> until the API is well established.

"something decent" is already out - epoll is quite useful in its
present form. (Take that with a grain of salt - I haven't tried it,
and it only just went into 2.4.45, and I have the impression Davide is
cleaning up the code for 2.4.46 - but it looks basically ok).

-- Jamie
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