migration/dirtyrate: Implement set_sample_page_period() and is_sample_period_valid()

Implement is_sample_period_valid() to check if the sample period is vaild and
do set_sample_page_period() to sleep specific time between sample actions.

Signed-off-by: Chuan Zheng <zhengchuan@huawei.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: David Edmondson <david.edmondson@oracle.com>
Reviewed-by: Li Qiang <liq3ea@gmail.com>
Message-Id: <1600237327-33618-10-git-send-email-zhengchuan@huawei.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

1 files changed, 24 insertions, 0 deletions

diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
index ee47e2bc27..20216c5f09 100644
--- a/migration/dirtyrate.c
+++ b/migration/dirtyrate.c
@@ -27,6 +27,30 @@
 static int CalculatingState = DIRTY_RATE_STATUS_UNSTARTED;
 static struct DirtyRateStat DirtyStat;
 
+static int64_t set_sample_page_period(int64_t msec, int64_t initial_time)
+{
+    int64_t current_time;
+
+    current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
+    if ((current_time - initial_time) >= msec) {
+        msec = current_time - initial_time;
+    } else {
+        g_usleep((msec + initial_time - current_time) * 1000);
+    }
+
+    return msec;
+}
+
+static bool is_sample_period_valid(int64_t sec)
+{
+    if (sec < MIN_FETCH_DIRTYRATE_TIME_SEC ||
+        sec > MAX_FETCH_DIRTYRATE_TIME_SEC) {
+        return false;
+    }
+
+    return true;
+}
+
 static int dirtyrate_set_state(int *state, int old_state, int new_state)
 {
     assert(new_state < DIRTY_RATE_STATUS__MAX);