[LAU] 200 lines kernel patch

[Philipp Überbacher]

Excerpts from Niels Mayer's message of 2010-11-24 07:55:46 +0100:
> http://lwn.net/SubscriberLink/415740/54028f24b103f4ff/
> ...............................
> "Most outspoken - as he often is - is Lennart Poettering, who asserted
> that "Binding something like this to TTYs is just backwards"; he would
> rather see something which is based on sessions. And, he said, all of
> this could better be done in user space. Linus was, to put it
> politely, unimpressed, but Lennart came back with a few lines of bash
> scripting which achieves the same result as Mike's patch - with no
> kernel patching required at all. It turns out that working with
> control groups is not necessarily that hard."
> ................................
> 
> Have these people arguing against Lennart ever heard of GUI apps? And
> what exactly is the "TTY" of an application "in the cloud."  And how
> exactly would keying off the tty be used in a paravirtualized kernel?
> 
> For example, many GUI based programs run out of pty's by running
> subprocesses or networked subprocesses. This includes applications
> based on libexpect(3), Qt apps using QProcess, or emacs subprocesses.
> How would this silly kernel-bloating  hack work with such programs?
> 
> So IMHO, this is design based on the flawed logic of "If the only tool
> you have is a terminal emulator everything begins to look like a text
> based program"
> 
> Lennart agrees:
> 
> http://lwn.net/Articles/415756/
> ...............
> "Well, this feature is pretty much interesting only for kernel hackers
> anyway. It is completely irrelevant for normal desktop people. Because
> a) normal users don't use many terminals anyway and that very seldom and
> b) if they do that they do not create gazillion of processes from one of
> the terminals and only very few in the other. Because only then this
> patch becomes relevant.
> 
> Heck, the patch wouldn't even have any effect on my machine (and I am
> hacker), because I tend to run my builds from within emacs. And since
> emacs has no TTY (since it is a X11/gtk build) it wouldn't be in its own
> scheduling group."
> .....................
> 
> -- Niels
> http://nielsmayer.com

I recommend reading the original discussion on lkml