Re: [Qemu-devel] [PATCH 2/3] net: Flush queues when runstate changes back to running

[zhanghailiang]

On 2014/8/14 15:12, Gonglei (Arei) wrote:
> Hi,
>
> > Subject: [Qemu-devel] [PATCH 2/3] net: Flush queues when runstate changes
> > back to running
> >
> > When the runstate changes back to running, we definitely need to flush
> > queues to get packets flowing again.
> >
> > Here we implement this in the net layer:
> > (1) add a member 'VMChangeStateEntry *vmstate' to struct NICState,
> > Which will listen for VM runstate changes.
>
> Does this change will block migration during with different QEMU versions?

No, I have tested migration between qemu-1.5.1 with new qemu which has
merged this patches, everything seems ok!

> > (2) Register a handler function for VMstate change.
> > When vm changes back to running, we flush all queues in the callback function.
> >
> > Signed-off-by: zhanghailiang<address@hidden>
> > ---
> >   include/net/net.h |  1 +
> >   net/net.c         | 26 ++++++++++++++++++++++++++
> >   2 files changed, 27 insertions(+)
> >
> > diff --git a/include/net/net.h b/include/net/net.h
> > index 312f728..a294277 100644
> > --- a/include/net/net.h
> > +++ b/include/net/net.h
> > @@ -97,6 +97,7 @@ typedef struct NICState {
> >       NICConf *conf;
> >       void *opaque;
> >       bool peer_deleted;
> > +    VMChangeStateEntry *vmstate;
> >   } NICState;
> >
> >   NetClientState *qemu_find_netdev(const char *id);
> > diff --git a/net/net.c b/net/net.c
> > index 5bb2821..506e58f 100644
> > --- a/net/net.c
> > +++ b/net/net.c
> > @@ -242,6 +242,29 @@ NetClientState *qemu_new_net_client(NetClientInfo
> > *info,
> >       return nc;
> >   }
> >
> > +static void nic_vmstate_change_handler(void *opaque,
> > +                                       int running,
> > +                                       RunState state)
> > +{
> > +    NICState *nic = opaque;
> > +    NetClientState *nc;
> > +    int i, queues;
> > +
> > +    if (!running) {
> > +        return;
> > +    }
> > +
> > +    queues =  MAX(1, nic->conf->peers.queues);
>                ^
> A superfluous space.

Yes, Good catch, i will modify this. Thanks.