sched/debug: Implement consistent task-state printing

Currently get_task_state() and task_state_to_char() report different
states, create a number of common helpers and unify the reported state
space.

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>

diff --git a/fs/proc/array.c b/fs/proc/array.c
index 525157c..01196d3 100644 (file)
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -130,19 +130,8 @@ static const char * const task_state_array[] = {
 
 static inline const char *get_task_state(struct task_struct *tsk)
 {
-       unsigned int state = (tsk->state | tsk->exit_state) & TASK_REPORT;
-
-       /*
-        * Parked tasks do not run; they sit in __kthread_parkme().
-        * Without this check, we would report them as running, which is
-        * clearly wrong, so we report them as sleeping instead.
-        */
-       if (tsk->state == TASK_PARKED)
-               state = TASK_INTERRUPTIBLE;
-
-       BUILD_BUG_ON(1 + ilog2(TASK_REPORT) != ARRAY_SIZE(task_state_array)-1);
-
-       return task_state_array[fls(state)];
+       BUILD_BUG_ON(1 + ilog2(TASK_REPORT) != ARRAY_SIZE(task_state_array) - 1);
+       return task_state_array[__get_task_state(tsk)];
 }
 
 static inline int get_task_umask(struct task_struct *tsk)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 92fb8dd..163a0b7 100644 (file)
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1243,17 +1243,29 @@ static inline pid_t task_pgrp_nr(struct task_struct *tsk)
        return task_pgrp_nr_ns(tsk, &init_pid_ns);
 }
 
-static inline char task_state_to_char(struct task_struct *task)
+static inline unsigned int __get_task_state(struct task_struct *tsk)
 {
-       const char stat_nam[] = TASK_STATE_TO_CHAR_STR;
-       unsigned long state = task->state;
+       unsigned int tsk_state = READ_ONCE(tsk->state);
+       unsigned int state = (tsk_state | tsk->exit_state) & TASK_REPORT;
 
-       state = state ? __ffs(state) + 1 : 0;
+       if (tsk_state == TASK_PARKED)
+               state = TASK_INTERRUPTIBLE;
 
-       /* Make sure the string lines up properly with the number of task states: */
-       BUILD_BUG_ON(sizeof(TASK_STATE_TO_CHAR_STR)-1 != ilog2(TASK_STATE_MAX)+1);
+       return fls(state);
+}
+
+static inline char __task_state_to_char(unsigned int state)
+{
+       static const char state_char[] = "RSDTtXZ";
+
+       BUILD_BUG_ON(1 + ilog2(TASK_REPORT) != sizeof(state_char) - 2);
 
-       return state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?';
+       return state_char[state];
+}
+
+static inline char task_state_to_char(struct task_struct *tsk)
+{
+       return __task_state_to_char(__get_task_state(tsk));
 }
 
 /**