Re: [Qemu-devel] [PATCH v8 00/54] Postcopy implementation

[Dr. David Alan Gilbert]

* Bharata B Rao (address@hidden) wrote:
> On Wed, Sep 30, 2015 at 11:53:04AM +0100, Dr. David Alan Gilbert wrote:
> > * Bharata B Rao (address@hidden) wrote:
> > > On Mon, Sep 28, 2015 at 05:51:39PM +0100, Dr. David Alan Gilbert (git) 
> > > wrote:
> > > > From: "Dr. David Alan Gilbert" <address@hidden>
> > > > 
> > > >   This is the 8th cut of my version of postcopy.
> > > > 
> > > > The userfaultfd linux kernel code is now in the upstream kernel
> > > > tree, and so 4.3-rc3 can be used without modification.
> > > > 
> > > > This qemu series can be found at:
> > > > https://github.com/orbitfp7/qemu.git
> > > > on the wp3-postcopy-v8 tag
> > > > 
> > > > 
> > > > Testing status:
> > > >   * Tested heavily on x86
> > > >   * Smoke tested on aarch64 (so it does work on different page sizes)
> > > >   * Power is unhappy for me (but gets further than the htab problem
> > > >     v7 used to have) (I get a kvm run failed)
> > > 
> > > Seems to be completing successfully on Power. But it takes 2min for the
> > > migration status to transition from setup to active.
> > > 
> > > Host: 4.3.0-rc3+
> > > Guest: 4.3.0-rc3+
> > > QEMU: wp3-postcopy-v8 of your tree.
> > > 
> > > # ./ppc64-softmmu/qemu-system-ppc64 --enable-kvm --nographic -machine 
> > > pseries -m 8G,slots=32,maxmem=32G -device virtio-blk-pci,drive=rootdisk 
> > > -drive 
> > > file=/home/bharata/F20-snap1,if=none,cache=none,id=rootdisk,format=qcow2 
> > > -vga none -net nic,model=virtio -net user -redir tcp:2000::22 -smp 
> > > 16,maxcpus=32 -serial pty
> > > 
> > > (qemu) migrate_set_capability x-postcopy-ram on
> > > (qemu) migrate -d tcp:localhost:4444
> > > (qemu) info migrate
> > > capabilities: xbzrle: off rdma-pin-all: off auto-converge: off 
> > > zero-blocks: off compress: off events: off x-postcopy-ram: on 
> > > Migration status: setup
> > > total time: 0 milliseconds
> > > 
> > > same status for around 2min...
> > 
> > That's interesting; I saw that behaviour on my aarch64 box, but not on
> > my power box or on x86.  Can you try using tcp:127.0.0.1:4444 to force
> > ipv4 (that fixed it for me on aarch64).  On the aarch box I found that
> > it still happened with head of tree qemu and so decided it wasn't my
> > postcopy world; I'm assuming what's happening is that it's trying
> > to connect to the IPv6 address, timing out and then trying IPv4.
> 
> Yes, s/localhost/127.0.0.1 helps.

OK; it sounds like there's something 'fun' going on with either the
bleeding edge kernel or the bleeding edge qemu with IPv6 then.

> > 
> > Great; is the guest happy?
> 
> Yes, survived a reboot, postcopy migration back to the original host
> and then a reboot.

OK, great.

Dave

> Regards,
> Bharata.
> 
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK