Re: [Gnu-arch-users] tla-pqm 0.2

[zander]

On Fri, Oct 17, 2003 at 10:15:42AM -0400, Colin Walters wrote:
> On Fri, 2003-10-17 at 04:08, Thomas Zander wrote:
> > - - daemon mode which uses dnotify (the kernel command) to wakeup as soon 
> > as a 
> > request comes in.
> 
> Heh.  Funny you requested this - the software that I based tla-pqm off
> of (mini-dinstall) does support this.  However, it is also rather
> fragile and unreliable, mainly due to the "dnotify" shell command.

As long as you have a kernel that supports this (>= 2.4.18) my experience
has been a rather pleasant one.

> Also, a daemon mode would add a fair amount of complexity to the
> program, and in the end I don't see significant advantages to it.

My take has always been to keep a looping process around your main application,
that is about 15 lines of c code.

When it wakes up (due to the dnotify) it starts a new client using fork
and goes back to sleep. There is some checking that not more then 2 clients
can be running at the same time.
As long as your application (the one started in the fork) does not start, but
waits until the lock is gone it works smoothly.

-- 
Thomas Zander

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