Merge remote-tracking branch 'torvalds/master' into perf/core

[linux-2.6-microblaze.git] / include / linux / sched.h

diff --git a/include/linux/sched.h b/include/linux/sched.h
index d2c8813..28a98fc 100644 (file)
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -350,11 +350,19 @@ struct load_weight {
  * Only for tasks we track a moving average of the past instantaneous
  * estimated utilization. This allows to absorb sporadic drops in utilization
  * of an otherwise almost periodic task.
+ *
+ * The UTIL_AVG_UNCHANGED flag is used to synchronize util_est with util_avg
+ * updates. When a task is dequeued, its util_est should not be updated if its
+ * util_avg has not been updated in the meantime.
+ * This information is mapped into the MSB bit of util_est.enqueued at dequeue
+ * time. Since max value of util_est.enqueued for a task is 1024 (PELT util_avg
+ * for a task) it is safe to use MSB.
  */
 struct util_est {
        unsigned int                    enqueued;
        unsigned int                    ewma;
 #define UTIL_EST_WEIGHT_SHIFT          2
+#define UTIL_AVG_UNCHANGED             0x80000000
 } __attribute__((__aligned__(sizeof(u64))));
 
 /*