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

[Bharata B Rao <bharata@linux.vnet.ibm.com>]

On Wed, Sep 30, 2015 at 05:14:48PM +0100, Dr. David Alan Gilbert wrote:
> * Bharata B Rao (bharata@linux.vnet.ibm.com) wrote:
> > On Wed, Sep 30, 2015 at 11:53:04AM +0100, Dr. David Alan Gilbert wrote:
> > > * Bharata B Rao (bharata@linux.vnet.ibm.com) wrote:
> > > > On Mon, Sep 28, 2015 at 05:51:39PM +0100, Dr. David Alan Gilbert (git) wrote:
> > > > > From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> > > > > 
> > > > >   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.

It's the host kernel. Until 4.3.0-rc2 it works, the problem starts
from 4.3.0-rc3. Accessing monitor on localhost using telnet is also affected.

Regards,
Bharata.