[PATCH 3/3] sched/core: Update task_prio() function header

[Dietmar Eggemann <dietmar.eggemann@arm.com>]

The description of the RT offset and the values for 'normal' tasks needs
update. Moreover there are DL tasks now.
task_prio() has to stay like it is to guarantee compatibility with the
/proc/<pid>/stat priority field:

  # cat /proc/<pid>/stat | awk '{ print $18; }'

Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
---
 kernel/sched/core.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 625ec1e12064..be3a956c2d23 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5602,8 +5602,12 @@ SYSCALL_DEFINE1(nice, int, increment)
  * @p: the task in question.
  *
  * Return: The priority value as seen by users in /proc.
- * RT tasks are offset by -200. Normal tasks are centered
- * around 0, value goes from -16 to +15.
+ *
+ * sched policy         return value   kernel prio    user prio/nice
+ *
+ * normal, batch, idle     [0 ... 39]  [100 ... 139]          0/[-20 ... 19]
+ * fifo, rr             [-2 ... -100]     [98 ... 0]  [1 ... 99]
+ * deadline                     -101             -1           0
  */
 int task_prio(const struct task_struct *p)
 {
-- 
2.25.1