Messages in this thread | | | Subject | Re: [Ksummit-2010-discuss] checkpoint-restart: naked patch | From | Dan Smith <> | Date | Mon, 08 Nov 2010 11:05:48 -0800 |
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GC> As before, Oren, let's have that phone discussion so that we can GC> preprocess a lot of this, instead of acting like the the three GC> blind men and the elephant. I will _tell you_ the strengths and GC> weaknesses of DMTCP on the phone, instead of you having to guess GC> at them here on LKML. And of course, I hope you will be similarly GC> frank about Linux C/R on the phone.
I want to be in on that discussion too, as do a lot of other people here. However, I doubt we'll all be able to find a common spot on our collective schedules, nor would that conversation be archived for posterity. I think sticking to LKML is the right (and time-tested) approach.
OL> Linux-cr can do live migration - e.g. VDI, move the desktop - in OL> which case skype's sockets' network stacks are reconstructed, OL> transparently to both skype (local apps) and the peer (remote OL> apps). Then, at the destination host and skype continues to work.
GC> That's a really cool thing to do, and it's definitely not part of GC> what DMTCP does. It might be possible to do userland live GC> migration, but it's definitely not part of our current scope.
How would you go about doing that in userland? With the current linux-cr implementation, I can move something like sshd or sendmail from one machine to another without a remote (connected) client noticing anything more than a bit of delay during the move.
I think that saving and restoring the state of a TCP connection from userland is probably a good example of a case where it makes sense to have it as part of a C/R function, but not necessarily exposed in /sys or /proc somewhere. Unless it can be argued that doing so is not useful, I think that's a good talking point for discussing the kernel vs. user approach, no?
-- Dan Smith IBM Linux Technology Center
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