Re: [PATCH v7 3/5] migration: Add zero-copy parameter for QMP/HMP for Linux

[Leonardo Bras Soares Passos]

Hello Juan,
Thanks for thew feedback!


On Fri, Feb 18, 2022 at 1:31 PM Juan Quintela <quintela@redhat.com> wrote:
>
> Leonardo Bras Soares Passos <leobras@redhat.com> wrote:
> > On Wed, Jan 19, 2022 at 3:16 PM Daniel P. Berrangé <berrange@redhat.com> 
> > wrote:
> >>
> >> On Wed, Jan 19, 2022 at 03:03:29PM -0300, Leonardo Bras Soares Passos 
> >> wrote:
> >> > Hello Daniel,
> >> >
> >> > On Thu, Jan 13, 2022 at 10:10 AM Daniel P. Berrangé 
> >> > <berrange@redhat.com> wrote:
> >> > >
> >> > > On Thu, Jan 06, 2022 at 07:13:40PM -0300, Leonardo Bras wrote:
> >> > > > Add property that allows zero-copy migration of memory pages,
> >> > > > and also includes a helper function migrate_use_zero_copy() to check
> >> > > > if it's enabled.
> >> > > >
> >> > > > No code is introduced to actually do the migration, but it allow
> >> > > > future implementations to enable/disable this feature.
> >> > > >
> >> > > > On non-Linux builds this parameter is compiled-out.
> >> > > >
> >> > > > Signed-off-by: Leonardo Bras <leobras@redhat.com>
> >> > > > ---
> >> > > >  qapi/migration.json   | 24 ++++++++++++++++++++++++
> >> > > >  migration/migration.h |  5 +++++
> >> > > >  migration/migration.c | 32 ++++++++++++++++++++++++++++++++
> >> > > >  migration/socket.c    |  5 +++++
> >> > > >  monitor/hmp-cmds.c    |  6 ++++++
> >> > > >  5 files changed, 72 insertions(+)
> >> > >
> >> > > Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
> >> >
> >> > Thanks!
> >>
> >
> > Ok, I see the point.
> > I will try to refactor the code changing zero-copy to zero-copy-send
> > or something like that.
>
> Hi
>
> I am late to the party, but I agree with Dan that we need two flags.
>
> Thre reason is that you can be the target of one migration, and later be
> the source of a next one.  If we only have one flag that means different
> things on the source and destination side, things become really
> complicated.
>
> Later, Juan.
>

Yeah, that makes sense. :)

Best regards,
Leo