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    SubjectRe: C/R without "leaks" (was: Re: Creating tasks on restart: userspace vs kernel)
    On Thu, 2009-04-16 at 20:12 +0400, Alexey Dobriyan wrote:
    > On Thu, Apr 16, 2009 at 12:42:17AM +0200, Greg Kurz wrote:
    > > On Wed, 2009-04-15 at 23:56 +0400, Alexey Dobriyan wrote:
    > > > There are sockets and live netns as the most complex example. I'm not
    > > > prepared to describe it exactly, but people wishing to do C/R with
    > > > "leaks" should be very careful with their wishes.
    > >
    > > They should close their sockets before checkpoint and find/have some way
    > > to reconnect after. This implies some kind of C/R awareness in the code
    > > to be checkpointed.
    > How do you imagine sshd closing sockets and reconnecting?

    Dunno and it isn't really my concern... I'm interested in HPC jobs that
    can collaborate with the C/R feature. For examples, those jobs that use
    interconnect hardware that will never be *checkpointable*... Usually,
    the batch manager tells the jobs it's going to be checkpointed, so that
    it can disconnect/shrink memory/reach quiescent point, and reconnect
    after resuming execution.

    I understand you aim at supporting transparent C/R of connected TCP
    sockets. Nice feature. Could you give use cases where it's *really*
    helpful/needed/mandatory ?

    Gregory Kurz
    Software Engineer @ IBM/Meiosys
    Tel +33 (0)534 638 479 Fax +33 (0)561 400 420

    "Anarchy is about taking complete responsibility for yourself."
    Alan Moore.

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