[Qemu-devel] [PATCH v2 08/13] migration: use switch at the end of migration

Peter Xu posted 13 patches 7 years, 9 months ago
[Qemu-devel] [PATCH v2 08/13] migration: use switch at the end of migration
Posted by Peter Xu 7 years, 9 months ago
It converts the old if clauses into switch, explicitly mentions the
possible migration states.  The old nested "if"s are not clear on what
we do on different states.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 migration/migration.c | 44 +++++++++++++++++++++++++++-----------------
 1 file changed, 27 insertions(+), 17 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index 72f0b586f7..4dd21f8636 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -2302,26 +2302,30 @@ static void *migration_thread(void *opaque)
     cpu_throttle_stop();
 
     qemu_mutex_lock_iothread();
-    if (s->state == MIGRATION_STATUS_COMPLETED) {
+    switch (s->state) {
+    case MIGRATION_STATUS_COMPLETED:
         migration_calculate_complete(s);
         runstate_set(RUN_STATE_POSTMIGRATE);
-    } else {
-        if (s->state == MIGRATION_STATUS_ACTIVE) {
-            /*
-             * We should really assert here, but since it's during
-             * migration, let's try to reduce the usage of assertions.
-             */
-            if (!migrate_colo_enabled()) {
-                error_report("%s: critical error: calling COLO code without "
-                             "COLO enabled", __func__);
-            }
-            migrate_start_colo_process(s);
-            /*
-            * Fixme: we will run VM in COLO no matter its old running state.
-            * After exited COLO, we will keep running.
-            */
-            s->vm_was_running = true;
+        break;
+
+    case MIGRATION_STATUS_ACTIVE:
+        /*
+         * We should really assert here, but since it's during
+         * migration, let's try to reduce the usage of assertions.
+         */
+        if (!migrate_colo_enabled()) {
+            error_report("%s: critical error: calling COLO code without "
+                         "COLO enabled", __func__);
         }
+        migrate_start_colo_process(s);
+        /*
+         * Fixme: we will run VM in COLO no matter its old running state.
+         * After exited COLO, we will keep running.
+         */
+        s->vm_was_running = true;
+        /* Fallthrough */
+    case MIGRATION_STATUS_FAILED:
+    case MIGRATION_STATUS_CANCELLED:
         if (s->vm_was_running) {
             vm_start();
         } else {
@@ -2329,6 +2333,12 @@ static void *migration_thread(void *opaque)
                 runstate_set(RUN_STATE_POSTMIGRATE);
             }
         }
+        break;
+
+    default:
+        /* Should not reach here, but if so, forgive the VM. */
+        error_report("%s: Unknown ending state %d", __func__, s->state);
+        break;
     }
     qemu_bh_schedule(s->cleanup_bh);
     qemu_mutex_unlock_iothread();
-- 
2.14.3


Re: [Qemu-devel] [PATCH v2 08/13] migration: use switch at the end of migration
Posted by Juan Quintela 7 years, 9 months ago
Peter Xu <peterx@redhat.com> wrote:
> It converts the old if clauses into switch, explicitly mentions the
> possible migration states.  The old nested "if"s are not clear on what
> we do on different states.
>
> Signed-off-by: Peter Xu <peterx@redhat.com>

Reviewed-by: Juan Quintela <quintela@redhat.com>