sched/debug: Add explicit TASK_IDLE printing

Markus reported that kthreads that idle using TASK_IDLE instead of
TASK_INTERRUPTIBLE are reported in as TASK_UNINTERRUPTIBLE and things
like htop mark those red.

This is undesirable, so add an explicit state for TASK_IDLE.

Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 13 insertions, 8 deletions

diff --git a/fs/proc/array.c b/fs/proc/array.c
index 01196d3ad452..a120a4549d48 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -119,18 +119,23 @@ static inline void task_name(struct seq_file *m, struct task_struct *p)
  * simple bit tests.
  */
 static const char * const task_state_array[] = {
-        "R (running)",          /*   0 */
-        "S (sleeping)",         /*   1 */
-        "D (disk sleep)",       /*   2 */
-        "T (stopped)",          /*   4 */
-        "t (tracing stop)",     /*   8 */
-        "X (dead)",             /*  16 */
-        "Z (zombie)",           /*  32 */
+
+        /* states in TASK_REPORT: */
+        "R (running)",          /* 0x00 */
+        "S (sleeping)",         /* 0x01 */
+        "D (disk sleep)",       /* 0x02 */
+        "T (stopped)",          /* 0x04 */
+        "t (tracing stop)",     /* 0x08 */
+        "X (dead)",             /* 0x10 */
+        "Z (zombie)",           /* 0x20 */
+
+        /* states beyond TASK_REPORT: */
+        "I (idle)",             /* 0x40 */
 };
 
 static inline const char *get_task_state(struct task_struct *tsk)
 {
-        BUILD_BUG_ON(1 + ilog2(TASK_REPORT) != ARRAY_SIZE(task_state_array) - 1);
+        BUILD_BUG_ON(1 + ilog2(TASK_REPORT_MAX) != ARRAY_SIZE(task_state_array));
         return task_state_array[__get_task_state(tsk)];
 }