RE: [PATCH] migration: Move bitmap_mutex out of migration_bitmap_clear_dirty()

[Wang, Wei W]

On Tuesday, July 13, 2021 11:59 PM, Peter Xu wrote:
> On Tue, Jul 13, 2021 at 08:40:21AM +0000, Wang, Wei W wrote:
> 
> Didn't get a chance to document it as it's in a pull now; but as long as 
> you're okay
> with no-per-page lock (which I still don't agree with), I can follow this up.
> 
> Are below parameters enough for me to enable free-page-hint?
> 
>      -object iothread,id=io1 \
>      -device virtio-balloon,free-page-hint=on,iothread=io1 \
> 
> I tried to verify it's running by tracing inside guest with kprobe
> report_free_page_func() but it didn't really trigger.  Guest has kernel
> 5.11.12-300.fc34.x86_64, should be fairly new to have that supported.  Do you
> know what I'm missing?

Please check if you have the virtio-balloon driver loaded in the guest.

> 
> P.S. This also reminded me that, maybe we want an entry in qemu-options.hx for
> balloon device, as it has lots of options, some of them may not be easy to be
> setup right.
> 

Sounds good to me.

Best,
Wei