Re: [PATCH 1/3] colo-compare: return -1 if no packet is queued

[Li Zhijian]

On 9/23/20 9:41 AM, Zhang, Chen wrote:
> > -----Original Message-----
> > From: Li Zhijian <lizhijian@cn.fujitsu.com>
> > Sent: Tuesday, September 22, 2020 5:55 PM
> > To: Zhang, Chen <chen.zhang@intel.com>; jasowang@redhat.com
> > Cc: qemu-devel@nongnu.org; Li Zhijian <lizhijian@cn.fujitsu.com>
> > Subject: [PATCH 1/3] colo-compare: return -1 if no packet is queued
> >
> > Return 0 will trigger a packet comparison
> Yes, we need active trigger a checkpoint to flush all the queued packets here.
Previously, no new checkpoint will be triggered since no new packet is queued 
though colo_compare_connection() is called.
actually we should send a notify to colo frame immediately, no need to compare 
them any more in order to less latency.

diff --git a/net/colo-compare.c b/net/colo-compare.c
index 3a45d64175..23092e4496 100644
--- a/net/colo-compare.c
+++ b/net/colo-compare.c
@@ -285,10 +285,13 @@ static int packet_enqueue(CompareState *s, int mode, 
Connection **con)
     }

     if (!ret) {
+        /* queue is too long, do a checkpoint to release all queued packets */
+        colo_compare_inconsistency_notify(s);
         trace_colo_compare_drop_packet(colo_mode[mode],
             "queue size too big, drop packet");
         packet_destroy(pkt, NULL);
         pkt = NULL;
+        return -1;
     }

     *con = conn;


> Otherwise, we should drop all the packet after this time still next checkpoint.
> So, I think original logic is a better choice.
>
> Thanks
> Zhang Chen
>
> > Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
> > ---
> >   net/colo-compare.c | 1 +
> >   1 file changed, 1 insertion(+)
> >
> > diff --git a/net/colo-compare.c b/net/colo-compare.c index
> > 3a45d64175..039b515611 100644
> > --- a/net/colo-compare.c
> > +++ b/net/colo-compare.c
> > @@ -289,6 +289,7 @@ static int packet_enqueue(CompareState *s, int
> > mode, Connection **con)
> >               "queue size too big, drop packet");
> >           packet_destroy(pkt, NULL);
> >           pkt = NULL;
> > +        return -1;
> >       }
> >
> >       *con = conn;
> > --
> > 2.28.0