OoO En cette nuit nuageuse du mercredi 07 mars 2012, vers 00:21,
Fernando Lemos <fernandotcl@gmail.com> disait :
>> To give one particular example: systemd uses Linux-specific features to
>> accurately track all the processes started by a service, which allows
>> accurate monitoring and shutdown of processes which could otherwise
>> disassociate themselves from their parent processes via the usual
>> daemonizing trick. POSIX doesn't provide features that allow this in
>> general, but Linux does. (Quite possibly other OSes provide those
>> features too, but not in a standardized way.)
> By the way, upstart uses ptrace for this:
> http://netsplit.com/2007/12/07/how-to-and-why-supervise-forking-processes/
> It's an interesting trick, and probably more portable too.
Maybe we could have an intermediate goal to patch any daemon to add an
option to not fork on start. If any daemon can be started without
forking, it seems easy to start/stop them without cgroups. This would
allow to generate a sysvinit script from systemd service description. I
don't know any daemon that does not have a flag to not fork on
start. The number of daemons to patch may be low.
This will not be as clean as using cgroups, but it won't be worst than
the actual situation.
--
Vincent Bernat ☯ http://vincent.bernat.im
printk("Entering UltraSMPenguin Mode...\n");
2.2.16 /usr/src/linux/arch/sparc64/kernel/smp.c
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