Re: [Qemu-devel] post-copy is broken?

[Li, Liang Z]

> * Li, Liang Z (address@hidden) wrote:
> > > > > > I've run it directly, setting relevant QTEST_QEMU_BINARY.
> > > > >
> > > > > Interesting; it's failing reliably for me - but only with a
> > > > > reasonably freshly booted machine (so that the pages get THPd).
> > > >
> > > > The same here. Freshly booted machine with 64GiB ram. I've checked
> > > > /proc/vmstat: huge pages were allocated
> > >
> > > Thanks for testing.
> > >
> > > Damn; this is confusing now.  I've got a RHEL7 box with 4.6.0-rc3 on
> > > where it works, and a fedora24 VM where it fails (the f24 VM is
> > > where I did the bisect so it works fine with the older kernel on the f24
> userspace in that VM).
> > >
> > > So lets see:
> > >    works: Kirill's (64GB machine)
> > >           Dave's RHEL7 host (24GB RAM, dual xeon, RHEL7 userspace
> > > and kernel
> > > config)
> > >    fails: Dave's f24 VM (4GB RAM, 4 vcpus VM on my laptop24
> > > userspace and kernel config)
> > >
> > > So it's any of userspace, kernel config, machine hardware or hmm.
> > >
> > > My f24 box has transparent_hugepage_madvise, where my rhel7 has
> > > transparent_hugepage_always (but still works if I flip it to madvise
> > > at run time).  I'll try and get the configs closer together.
> > >
> > > Liang Li: Can you run my test on your setup which fails the migrate
> > > and tell me what your userspace is?
> > >
> > > (If you've not built my test yet, you might find you need to add a :
> > >    tests/postcopy-test$(EXESUF): tests/postcopy-test.o
> > >
> > >   to the tests/Makefile)
> > >
> >
> > Hi Dave,
> >
> >   How to build and run you test? I didn't do that before.
> 
> Apply the code in:
> http://lists.gnu.org/archive/html/qemu-devel/2016-04/msg02138.html
> 
> fix the:
> +            if ( ((b + 1) % 255) == last_byte && !hit_edge) {
> to:
> +            if ( ((b + 1) % 256) == last_byte && !hit_edge) {
> 
> to tests/Makefile
>    tests/postcopy-test$(EXESUF): tests/postcopy-test.o
> 
> and do a:
>     make check
> 
> in qemu.
> Then you can rerun the test with:
>     QTEST_QEMU_BINARY=path/to/qemu-system-x86_64 ./tests/postcopy-
> test
> 
> if it works, reboot and check it still works from a fresh boot.
> 
> Can you describe the system which your full test failed on? What distro on
> the host? What type of host was it tested on?
> 
> Dave
> 


Thanks, Dave

The host is CenOS7, its original kernel is 3.10.0-327.el7.x86_64 (CentOS 7.1?),
The hardware platform is HSW-EP with 64GB RAM.


> >
> > Thanks!
> > Liang
> >
> > >
> > > Dave
> > > >
> > > > --
> > > >  Kirill A. Shutemov
> > > --
> > > Dr. David Alan Gilbert / address@hidden / Manchester, UK
> --
> Dr. David Alan Gilbert / address@hidden / Manchester, UK