Re: [RFC] new syscall to allow notification when arbitrary pids die

[Chris Friesen <cfriesen@nortelnetworks.com>]

Doug McNaught wrote:
> Chris Friesen <cfriesen@nortelnetworks.com> writes:
> 
> 
>>>There's already a well established way to do what you want (get
>>>non-immediate notification of process death). What benefit would your
>>>approach give?
>>>
>>Its cheaper and faster.  It only costs a single call for each process,
>>and then you get notified immediately when it dies.
>>
> 
> Rather than a new syscall, what about a magic file or device that you
> can poll()? 

This is definately an option to consider.  The problem that I see with this is 
that when you are trying to monitor large numbers of processes you have to worry 
about running out of file descriptors, and select() is no longer as happy.

I have an actual real request to be able to monitor 5000 processes.  This would 
be a lot of file descriptors, and when select returns it would take some 
processing to figure out which one had an event.

It does have easier handling of multiple simultaneous deaths though...the signal 
method would probably want to use realtime signals to get signal queueing.

Chris



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