COLO: Synchronize PVM's state to SVM periodically

Do checkpoint periodically, the default interval is 200ms.
Signed-off-by: Nzhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: NLi Zhijian <lizhijian@cn.fujitsu.com>
Reviewed-by: NDr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: NAmit Shah <amit.shah@redhat.com>
Signed-off-by: NAmit Shah <amit@amitshah.net>

migration/colo.c

@@ -11,6 +11,7 @@
  */
 
 #include "qemu/osdep.h"
+#include "qemu/timer.h"
 #include "sysemu/sysemu.h"
 #include "migration/colo.h"
 #include "io/channel-buffer.h"
@@ -226,6 +227,7 @@ static void colo_process_checkpoint(MigrationState *s)
 {
     QIOChannelBuffer *bioc;
     QEMUFile *fb = NULL;
+    int64_t current_time, checkpoint_time = qemu_clock_get_ms(QEMU_CLOCK_HOST);
     Error *local_err = NULL;
     int ret;
 
@@ -254,10 +256,20 @@ static void colo_process_checkpoint(MigrationState *s)
     trace_colo_vm_state_change("stop", "run");
 
     while (s->state == MIGRATION_STATUS_COLO) {
+        current_time = qemu_clock_get_ms(QEMU_CLOCK_HOST);
+        if (current_time - checkpoint_time <
+            s->parameters.x_checkpoint_delay) {
+            int64_t delay_ms;
+
+            delay_ms = s->parameters.x_checkpoint_delay -
+                       (current_time - checkpoint_time);
+            g_usleep(delay_ms * 1000);
+        }
         ret = colo_do_checkpoint_transaction(s, bioc, fb);
         if (ret < 0) {
             goto out;
         }
+        checkpoint_time = qemu_clock_get_ms(QEMU_CLOCK_HOST);
     }
 
 out: