Re: How to notify app of changed cpu/mem/io node configuration?

[jlm_devel <jlm_devel@laposte.net>]

Paul Jackson wrote:

>>But speaking with another OS which uses this approach, they found that
>>vendors preferred the "run a script" approach anyway
>>    
>>
>
>Why are the "script" and the "signal" exclusive?  We seem to need both.
>
>I'd expect that the 'batch manager' or such would want a "script" of its
>choosing executed, as you describe.
>
>But I also expect that a signal mechanism is required to deliver notice:
>
>  from: the system service or its script (a batch manager, for example)
>
>    to: the target task (a long running Fortran job, for example)
>
>that some special code linked in the target task needs to make sense of
>the situation and invoke the appropriate mbind/set_mempolicy calls.
>
>Perhaps that "other OS" didn't have the difficulty we have of having to
>get the target task to issue a call or two on its own behalf that can
>not be issued 'by proxy'.
>
>  
>
>>The real killer was that we can't add signals without breaking glibc,
>>    
>>
>
>Yeah - I agree.  Don't count on glibc for anything.  Hence no new
>signals, and expect to be overloading an existing signal for these
>purposes, if it comes to that.
>
>  
>
I'm not uptodate but if Icorrectly remember hotplug executes scripts 
when recieving an event from the kernel.... nothing prevent then to 
create a script that do
for PID in $(ls /var/run/hotplug/signals); do
    kill -10 $PID;
done

which will send a SIGUSR1 to any process listed in /var/run/hotplug/signals

more you can write a small aplication using POSIX extended signal to 
pass some value to the processes.....

(by the way I perfer this method rather than DBUS.... because this is 
more "standard" and don't create again the wheel)


-------------------------------------------------------
This SF.Net email sponsored by Black Hat Briefings & Training.
Attend Black Hat Briefings & Training, Las Vegas July 24-29 - 
digital self defense, top technical experts, no vendor pitches, 
unmatched networking opportunities. Visit www.blackhat.com
_______________________________________________
Linux-hotplug-devel mailing list  http://linux-hotplug.sourceforge.net
Linux-hotplug-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel