Re: [PATCH 1/1] eventfd new tag EFD_VPOLL: generate epoll events

From: Roman Penyaev
Date: Thu Jun 06 2019 - 16:16:10 EST

Hi Renzo,

On 2019-06-03 17:00, Renzo Davoli wrote:
Hi Roman,

I sorry for the delay in my answer, but I needed to set up a minimal
tutorial to show what I am working on and why I need a feature like the
one I am proposing.

Please, have a look of the page here:
(everything can be downloaded and tested)

Is that similar to what user-mode linux does? I mean the principle.

I am not trying to port some tools to use user-space implemented
stacks or device
drivers/emulators, I am seeking to a general purpose approach.

You still intersect *each* syscall, why not to do the same for epoll_wait()
and replace events with correct value? Seems you do something similar already
in a vu_wrap_poll.c: wo_epoll_wait(), right?

Don't get me wrong, I really want to understand whether everything really
looks so bad without proposed change. It seems not, because the whole principle
is based on intersection of each syscall, thus one more one less - it does not
become more clean and especially does not look like a generic purpose solution,
which you seek. I may be wrong.