Re: AIO work in librt

[Jakub Jelinek <jakub at redhat dot com>]

On Fri, Apr 23, 2004 at 11:17:09AM -0500, Mark Brown wrote:
> Given this conversation from last year:
> 
> Andreas Jaeger wrote:
> > Ulrich Drepper <drepper at redhat dot com> writes:
> > > Andreas Jaeger wrote:
> > >> AFAIK Ben's kernel level implementation is in current 2.5 kernels.
> > >> Can we base now a glibc implementation on this?  Anybody already
> > >> working on this?
> > >
> > > I doN't think the kernel side is complete enough.
> > 
> > Ben, what is still missing on the kernel side?  Looking at fs/aio.c I
> > thought it was complete.
> 
> We are thinking about making this work in librt (and submitting it, of 
> course).
> Andreas, did you learn anything from Ben? Anyone else know of a
> factor that keeps this from being able to work?

RHEL glibc already includes the rtkaio glibc add-on which is librt using
the kernel AIO interface.
Unfortunately, the kernel side is very limited and doesn't have good
support for the things userland POSIX AIO needs (e.g. in the area of
notification and cancellation, or that many things are serialized in
the kernel rather than truely asynchronous; and from what I've heard
the 2.6 aio is even in worse shape than what we used to have in 2.4.x RHEL
kernels).

	Jakub