lkml.org 
[lkml]   [2004]   [Feb]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH 3/4] 2.6.2-rc2-mm2 CPU Hotplug: The Core

    On Tue, 3 Feb 2004, Rusty Russell wrote:

    > Wrong migration thread. The migration thread on CPU 1 has been asked to
    > push into CPU 0, which is now going down.

    you are right - this one place would have to be aware of CPUs going away.

    > Now I've slept on the "do it atomically" idea, I think it's a good one.
    > I've even worked out how to maintain the "last thread on CPU is the idle
    > thread", although I'd need to test in code.

    good!

    > In practice, any app which wants to scale with # CPUs needs to know when
    > CPUs are coming up, as well as going down. Ditto memory, etc. This
    > means they need to listen for the hotplug event (DBUS anyone?), or we
    > introduce a SIGRECONF (default ignored). But AFAICT, introducing a new
    > signal isn't possible (at least on x86) without breaking glibc.

    you can introduce a variable RT signal for this purpose no problem - and
    one would want to have a queued signal for this anyway. Ie. by default the
    notification is disabled, but a new syscall sets up the process to be
    notified of CPU up/down events, on a signal # picked by the app. But this
    this indeed is dbus domain ...

    Ingo
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2005-03-22 14:00    [W:0.031 / U:60.964 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site