Hi Andrew,
Thank you for your reply!
I do not know much about migration V2. Was it integrated to Xen? If
integrated, from which version?
Thank you!!
Best Regards,
Yunfang
2015-06-06 3:00 GMT+08:00 Andrew Cooper <andrew.coop...@citrix.com>:
> On 05/06/15 19:45, Konrad Rzeszutek Wilk wrote:
> > On Thu, Jun 04, 2015 at 10:27:06PM +0800, yunfang tai wrote:
> >> Hi all,
> > Hey!
> >> Recently, I am testing the TMEM support on Xen. I discovered that
> when
> >> enabled TMEM in ubuntu 14.10 as guest on Xen 4.1 & Xen 4.3, "xm save" &
> "xm
> >> restore“ failed after there are more than 1000 pages put in persistent
> pool
> >> of TMEM in Xen. My operations are list as follows:
> > Is it exactly 1000 or just about? I presume it does not matter how much
> but
> > that you discovered it by having 1000 of them?
> >
> >> In ubuntu guest (8 cores , 8GB):
> >> sudo modprobe tmem
> >> (than wait for the selfballoon to finish)
> >> dd if=/dev/zero of=/tmp/test.img bs=10M count=1000
> >> dd if=/tmp/test.img of=/dev/null bs=10M
> >> dd if=/tmp/test.img of=/dev/null bs=10M
> >> .........
> >> (until more than 1000 pages put in persistent pool)
> >> In Domain 0:
> >> (add tmem in grub.cfg)
> >> xm save ubuntu test.save
> >> xm restore ubuntu test.save
> >>
> >> When TMEM is not enabled, save & restore success after these operations.
> >> But if TMEM is enabled, save & restore fail.
> > Are there any errors from the logs? Anything?
> >> Does anyone test about save & restore when enabled TMEM in Xen?? Is
> there
> >> anything I do wrong?
> > Well lets see what broke. But I think Andrew discovered that the
> > migration protocol when it came to 'tmem' was not up to snuff. CC-ing him
> > just to confirm.
> >
> > (Andrew, for the persistent part of this - it conceptually should
> > get all of the tmem memory that pushed to the hypervisor back in the
> > image. When you were looking at migrationv2 did you just skim through
> > that or mostly ignored it?)
>
> Took a look at the code, attempted to figure out what was going on, then
> decided to ignore it for the time being.
>
> As a baseline, there is no error checking of hypercalls or their
> returned data putting the data into the stream.
>
> Migration v2 currently has no TMEM support, and I would suggest
> re-implementing it from scratch over attempting to port what currently
> exists for legacy.
>
> ~Andrew
>
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