migration: split use of MigrationState.total_time

It was used either to:

1. store initial timestamp of migration start, and
2. store total time used by last migration

Let's provide two parameters for each of them.  Mix use of the two is
slightly misleading.

Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/migration/migration.h b/migration/migration.h
index d84bc550b1..d1132b1cf7 100644
--- a/migration/migration.h
+++ b/migration/migration.h
@@ -115,6 +115,9 @@ struct MigrationState
     } rp_state;
 
     double mbps;
+    /* Timestamp when recent migration starts (ms) */
+    int64_t start_time;
+    /* Total time used by latest migration (ms) */
     int64_t total_time;
     int64_t downtime;
     int64_t expected_downtime;