Re: [Qemu-devel] [PATCH v8 07/11] migration: add bitmap for copied page

[Peter Xu <peterx@redhat.com>]

On Tue, Jun 13, 2017 at 09:10:46AM +0300, Alexey Perevalov wrote:
> On 06/13/2017 08:59 AM, Peter Xu wrote:
> >On Wed, Jun 07, 2017 at 12:46:34PM +0300, Alexey Perevalov wrote:
> >>This patch adds ability to track down already copied
> >>pages, it's necessary for calculation vCPU block time in
> >>postcopy migration feature, maybe for restore after
> >>postcopy migration failure.
> >>Also it's necessary to solve shared memory issue in
> >>postcopy livemigration. Information about copied pages
> >>will be transferred to the software virtual bridge
> >>(e.g. OVS-VSWITCHD), to avoid fallocate (unmap) for
> >>already copied pages. fallocate syscall is required for
> >>remmaped shared memory, due to remmaping itself blocks
> >>ioctl(UFFDIO_COPY, ioctl in this case will end with EEXIT
> >>error (struct page is exists after remmap).
> >>
> >>Bitmap is placed into RAMBlock as another postcopy/precopy
> >>related bitmaps. Helpers are in migration/ram.c, due to
> >>in this file is allowing to work with RAMBlock.
> >>
> >>Signed-off-by: Alexey Perevalov <a.perevalov@samsung.com>
> >Hi, Alexey,
> >
> >Besides all the existing comments, I would suggest you do all the
> >copied_map things in this single patch, so that it'll be easier for
> >others to work upon your work. E.g., move the bit_set() operations
> >here as well (currently it was in followup patches, and looks like
> >that's not enough since we need to capture copied_map even for precopy
> >phase), then this single patch can ideally be separated from the whole
> >series (and then I can work upon it :-).
> >
> >Or, please just let me know if you want me to do this for you. I can
> >post this as a standalone patch, with your s-o-b if you allow.
> 
> Hello Peter,
> I'm working with this patch in another patch series too.
> (it's about QEMU's shared memory and OVS-VSWITCHD,
> vhost-user use case).
> So if you need that I could resend this patch as separate patch.
> And it will be convenient to base both my patch set and you patches
> on top of it.

That'll be great!  Then please post this as standalone patch.

Thanks,

-- 
Peter Xu