[OT] long-lived spawners

[Harald Becker]

On 11.03.2015 16:34, Laurent Bercot wrote:
> On 11/03/2015 14:02, Denys Vlasenko wrote:
>> But that nldev process will exist for all time, right? That's not
>> elegant.
>> Ideally, this respawning logic should be in the kernel.
>
...
>   Needing daemons to answer notifications from userspace processes
> or the kernel is the Unix way. It's not Hurd's, it's not Plan 9's
> (AFAIK), but it's what we have, and it's not even that ugly. The
> listening and spawning logic will have to be somewhere anyway, so
> why not userspace ? Userspace memory is cheaper (because it can
> be swapped), userspace processes are safer, and processes are not
> a scarce resource.

And what is wrong with a long lived daemon?

Ok, what I see is brain damaged developers writing big monolithic long 
lived daemons, which suck up tons of memory and / or cpu power :( ...

... this is not what I understand of a carefully designed long lived 
daemon ... it is silliness pure ...

... on the other hand, long lived daemons are no problem, as long as 
they stay at low resource usage ... and don't try to do too complicated 
things in a single process (multi threaded or not).

IMO daemons are the Unix way of user space located watching, 
coordinating, and controlling instances, which may fire up the right 
handling jobs for matching events (or deliver appropriate signaling, 
messages, or commands to the handling instances).

--
Harald