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From: Paul Jackson <pj@sgi.com>
To: linux-hotplug@vger.kernel.org
Subject: Re: How to notify app of changed cpu/mem/io node configuration?
Date: Wed, 30 Jun 2004 12:26:49 +0000	[thread overview]
Message-ID: <20040630052649.0b1e98e1.pj@sgi.com> (raw)
In-Reply-To: <20040628173808.04718b83.pj@sgi.com>

jlm_devel writes:
> nothing prevent then to create a script that do

Yes - I quite agree:

 1) However it be that notice is given, a hotplug script can send it,
    in the case that the kernel first saw the event.  I was less
    focused on how the notice was sent, than I was with what form
    (signal, message, ...) the notice took when it arrived into the
    process context of the long running job needing to be moved.

 2) I too prefer signals over DBUS for the particular case I was trying
    to raise here, of delivering low bandwidth asynchronous notice to
    a long running application that it needed to run a little bit of
    specialized "memory placement" code within its process context.

Note that it's not always the kernel that first notices the event.  It
might also be a batch manager that decides it needs to move some long
running jobs around, to make room for additional work.  In such case,
the batch manager, not a hotplug script, would be sending the notice.

I would not go so far as to describe D-BUS as reinventing the signal
wheel.  These are two different mechanisms, useful for different needs. 
If anything, D-BUS reinvents the CORBA wheel, which some would say was
pregnant with opportunities for reinvention.

-- 
                          I won't rest till it's the best ...
                          Programmer, Linux Scalability
                          Paul Jackson <pj@sgi.com> 1.650.933.1373


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  parent reply	other threads:[~2004-06-30 12:26 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-06-29  0:38 How to notify app of changed cpu/mem/io node configuration? Paul Jackson
2004-06-29  6:24 ` Greg KH
2004-06-29  8:37 ` Paul Jackson
2004-06-29 22:41 ` Dave Hansen
2004-06-29 23:15 ` Paul Jackson
2004-06-29 23:39 ` Dave Hansen
2004-06-29 23:53 ` Rusty Russell
2004-06-30  1:22 ` Paul Jackson
2004-06-30  1:38 ` Dave Hansen
2004-06-30  1:40 ` Paul Jackson
2004-06-30  2:16 ` Paul Jackson
2004-06-30 11:57 ` jlm_devel
2004-06-30 12:26 ` Paul Jackson [this message]
2004-06-30 13:08 ` Paul Jackson
2004-06-30 17:37 ` jlm_devel

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