From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Jackson Date: Tue, 29 Jun 2004 23:15:28 +0000 Subject: Re: How to notify app of changed cpu/mem/io node configuration? Message-Id: <20040629161528.213c6e10.pj@sgi.com> List-Id: References: <20040628173808.04718b83.pj@sgi.com> In-Reply-To: <20040628173808.04718b83.pj@sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-hotplug@vger.kernel.org Dave wrote: > But, we'll probably need some kind of synchronous process notification > at some point. Did you mean "some kind of asynchronous ..."? > If ... app ... hopeless ... the kernel will likely have the option to > kill it. More commonly, it seems that the kernel just forces the app onto some CPU/Memory that will work, such as the lowest currently online CPU. Essentially, CPU 0 (and I guess Memory Node 0, in time) become the orphanage for homeless tasks. > Sleeping for 5 seconds and hoping for the best probably isn't the best > option, either. :) Yeah - the kernel doesn't really want to be playing such games. Hence actions that might require such should be left to userland. For example, on orderly moving of apps from one Node to another could be accomplished by user code that took its time and did what it had to do to move (or kill) apps off old Node, before it told the kernel "all clear - remove old Node from service" > I wonder if a much more generic signal could be of more use ... That's my inclination as well. These sorts of events are rare. Send one generic signal, and let the recipient poke around and figure out what has changed that it cares about and deal with it. I could even imagine overloading SIGPWR for this purpose, if new signal numbers/names are too difficult to come by. -- I won't rest till it's the best ... Programmer, Linux Scalability Paul Jackson 1.650.933.1373 ------------------------------------------------------- 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