[PATCH v10 02/12] migration/dirtyrate: add DirtyRateStatus to denote calculation status

[Chuan Zheng <zhengchuan@huawei.com>]

add DirtyRateStatus to denote calculating status.

Signed-off-by: Chuan Zheng <zhengchuan@huawei.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Li Qiang <liq3ea@gmail.com>
---
 migration/dirtyrate.c | 26 ++++++++++++++++++++++++++
 qapi/migration.json   | 17 +++++++++++++++++
 2 files changed, 43 insertions(+)

diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
index bf7fd24..7bea8ff 100644
--- a/migration/dirtyrate.c
+++ b/migration/dirtyrate.c
@@ -22,6 +22,19 @@
 #include "migration.h"
 #include "dirtyrate.h"
 
+static int CalculatingState = DIRTY_RATE_STATUS_UNSTARTED;
+
+static int dirtyrate_set_state(int *state, int old_state, int new_state)
+{
+    assert(new_state < DIRTY_RATE_STATUS__MAX);
+    if (atomic_cmpxchg(state, old_state, new_state) == old_state) {
+        return 0;
+    } else {
+        return -1;
+    }
+}
+
+
 static void calculate_dirtyrate(struct DirtyRateConfig config)
 {
     /* todo */
@@ -31,8 +44,21 @@ static void calculate_dirtyrate(struct DirtyRateConfig config)
 void *get_dirtyrate_thread(void *arg)
 {
     struct DirtyRateConfig config = *(struct DirtyRateConfig *)arg;
+    int ret;
+
+    ret = dirtyrate_set_state(&CalculatingState, DIRTY_RATE_STATUS_UNSTARTED,
+                              DIRTY_RATE_STATUS_MEASURING);
+    if (ret == -1) {
+        error_report("change dirtyrate state failed.");
+        return NULL;
+    }
 
     calculate_dirtyrate(config);
 
+    ret = dirtyrate_set_state(&CalculatingState, DIRTY_RATE_STATUS_MEASURING,
+                              DIRTY_RATE_STATUS_MEASURED);
+    if (ret == -1) {
+        error_report("change dirtyrate state failed.");
+    }
     return NULL;
 }
diff --git a/qapi/migration.json b/qapi/migration.json
index 5f6b061..061ff25 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -1720,3 +1720,20 @@
 ##
 { 'event': 'UNPLUG_PRIMARY',
   'data': { 'device-id': 'str' } }
+
+##
+# @DirtyRateStatus:
+#
+# An enumeration of dirtyrate status.
+#
+# @unstarted: the dirtyrate thread has not been started.
+#
+# @measuring: the dirtyrate thread is measuring.
+#
+# @measured: the dirtyrate thread has measured and results are available.
+#
+# Since: 5.2
+#
+##
+{ 'enum': 'DirtyRateStatus',
+  'data': [ 'unstarted', 'measuring', 'measured'] }
-- 
1.8.3.1