On 2016/10/26 13:25, Amit Shah wrote:
On (Tue) 18 Oct 2016 [20:10:02], zhanghailiang wrote:
We need communications protocol of user-defined to control
the checkpointing process.
The new checkpointing request is started by Primary VM,
and the interactive process like below:
Checkpoint synchronizing points:
Primary Secondary
initial work
'checkpoint-ready' <-------------------- @
'checkpoint-request' @ -------------------->
Suspend (Only in hybrid mode)
'checkpoint-reply' <-------------------- @
Suspend&Save state
'vmstate-send' @ -------------------->
Send state Receive state
'vmstate-received' <-------------------- @
Release packets Load state
'vmstate-load' <-------------------- @
Resume Resume (Only in hybrid mode)
Start Comparing (Only in hybrid mode)
NOTE:
1) '@' who sends the message
2) Every sync-point is synchronized by two sides with only
one handshake(single direction) for low-latency.
If more strict synchronization is required, a opposite direction
sync-point should be added.
3) Since sync-points are single direction, the remote side may
go forward a lot when this side just receives the sync-point.
4) For now, we only support 'periodic' checkpoint, for which
the Secondary VM is not running, later we will support 'hybrid' mode.
Signed-off-by: zhanghailiang <zhang.zhanghaili...@huawei.com>
Signed-off-by: Li Zhijian <lizhij...@cn.fujitsu.com>
Signed-off-by: Gonglei <arei.gong...@huawei.com>
Cc: Eric Blake <ebl...@redhat.com>
Cc: Markus Armbruster <arm...@redhat.com>
Cc: Dr. David Alan Gilbert <dgilb...@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
Reviewed-by: Amit Shah <amit.s...@redhat.com>
+static int colo_do_checkpoint_transaction(MigrationState *s)
+{
+ Error *local_err = NULL;
+
+ colo_send_message(s->to_dst_file, COLO_MESSAGE_CHECKPOINT_REQUEST,
+ &local_err);
+ if (local_err) {
+ goto out;
+ }
+
+ colo_receive_check_message(s->rp_state.from_dst_file,
+ COLO_MESSAGE_CHECKPOINT_REPLY, &local_err);
+ if (local_err) {
+ goto out;
+ }
+
+ /* TODO: suspend and save vm state to colo buffer */
I like how you've split up the patches - makes it easier to review.
Thanks for doing this!
You're welcome. I'm glad to make your maintainers' review easy. :)
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -785,6 +785,31 @@
{ 'command': 'migrate-start-postcopy' }
##
+# @COLOMessage
+#
+# The message transmission between PVM and SVM
Can you expand PVM and SVM for the first use? It's obvious to someone
Quit reasonable. I will fix it in next version.
who's familiar with COLO, but someone looking at the api may not know
what it all means. Also, please expand COLO if not already done in
the qapi-schema file.
You are right, the full name of COLO appears in patch one, I'll add it
there.
Thanks.
hailiang
Amit
.
