[LSF/MM TOPIC][ATTEND] Improving async io, specifically io_submit latencies

[Ankit Jain <jankit@suse.de>]

Hi,

I'm interested in discussing how to improve async io api in the kernel,
specifically io_submit latencies.

I am working on trying to make io_submit non-blocking. I had posted a
patch[1] for this earlier on fsdevel and there was some discussion on
it. I have made some of the improvements suggested there.

The approach attempted in that patch essentially tries to service the
requests on a separate kernel thread. It was pointed out that this would
need to ensure that there aren't any unknown task_struct references or
dependencies under f_op->aio* which might get confused because of the
kernel thread. Would this kinda full audit be enough or would be it
considered too fragile?

I would like to discuss whether this is best approach for solving this
problem, and/or discuss some of the other possible approaches to solving
this issue.

This has been discussed in the past but we don't seem to have a solution
as of now.

References:
1. http://comments.gmane.org/gmane.linux.kernel.aio.general/3142

Regards,
-- 
Ankit Jain
SUSE Labs