sched/deadline: Fix the description of runtime accounting in the documentation

Signed-off-by: Claudio Scordino <[e-mail]>
Signed-off-by: Luca Abeni <[e-mail]>
Acked-by: Daniel Bristot de Oliveira <[e-mail]>
Acked-by: Peter Zijlstra <[e-mail]>
Cc: Jonathan Corbet <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Cc: Mathieu Poirier <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: Tommaso Cucinotta <[e-mail]>
Cc: [e-mail]
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>

Documentation/scheduler/sched-deadline.txt

···
  It does so by decrementing the runtime of the executing task Ti at a pace equal
  to
 
-           dq = -max{ Ui, (1 - Uinact) } dt
+           dq = -max{ Ui / Umax, (1 - Uinact - Uextra) } dt
 
- where Uinact is the inactive utilization, computed as (this_bq - running_bw),
- and Ui is the bandwidth of task Ti.
+ where:
+
+  - Ui is the bandwidth of task Ti;
+  - Umax is the maximum reclaimable utilization (subjected to RT throttling
+    limits);
+  - Uinact is the (per runqueue) inactive utilization, computed as
+    (this_bq - running_bw);
+  - Uextra is the (per runqueue) extra reclaimable utilization
+    (subjected to RT throttling limits).
 
 
  Let's now see a trivial example of two deadline tasks with runtime equal