[patch V3 03/64] sched: Reorganize current::__state helpers

Thomas Gleixner
2021-08-05T15:41:48Z

In order to avoid more duplicate implementations for the debug and
non-debug variants of the state change macros, split the debug portion out
and make that conditional on CONFIG_DEBUG_ATOMIC_SLEEP.

Suggested-by: Waiman Long <longman@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
V3: New patch.
---
include/linux/sched.h | 48 +++++++++++++++++++++++-------------------------
1 file changed, 23 insertions(+), 25 deletions(-)

--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -123,8 +123,6 @@ struct task_group;

#define task_is_stopped_or_traced(task) ((READ_ONCE(task->__state) & (__TASK_STOPPED | __TASK_TRACED)) != 0)

-#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
-
/*
* Special states are those that do not use the normal wait-loop pattern. See
* the comment with set_special_state().
@@ -132,30 +130,24 @@ struct task_group;
#define is_special_task_state(state) \
((state) & (__TASK_STOPPED | __TASK_TRACED | TASK_PARKED | TASK_DEAD))

-#define __set_current_state(state_value) \
- do { \
- WARN_ON_ONCE(is_special_task_state(state_value));\
- current->task_state_change = _THIS_IP_; \
- WRITE_ONCE(current->__state, (state_value)); \
- } while (0)
-
-#define set_current_state(state_value) \
- do { \
- WARN_ON_ONCE(is_special_task_state(state_value));\
- current->task_state_change = _THIS_IP_; \
- smp_store_mb(current->__state, (state_value)); \
+#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
+# define debug_normal_state_change(state_value) \
+ do { \
+ WARN_ON_ONCE(is_special_task_state(state_value)); \
+ current->task_state_change = _THIS_IP_; \
} while (0)

-#define set_special_state(state_value) \
+# define debug_special_state_change(state_value) \
do { \
- unsigned long flags; /* may shadow */ \
WARN_ON_ONCE(!is_special_task_state(state_value)); \
- raw_spin_lock_irqsave(&current->pi_lock, flags); \
current->task_state_change = _THIS_IP_; \
- WRITE_ONCE(current->__state, (state_value)); \
- raw_spin_unlock_irqrestore(&current->pi_lock, flags); \
} while (0)
+
#else
+# define debug_normal_state_change(cond) do { } while (0)
+# define debug_special_state_change(cond) do { } while (0)
+#endif
+
/*
* set_current_state() includes a barrier so that the write of current->state
* is correctly serialised wrt the caller's subsequent test of whether to
@@ -194,27 +186,33 @@ struct task_group;
* Also see the comments of try_to_wake_up().
*/
#define __set_current_state(state_value) \
- WRITE_ONCE(current->__state, (state_value))
+ do { \
+ debug_normal_state_change((state_value)); \
+ WRITE_ONCE(current->__state, (state_value)); \
+ } while (0)

#define set_current_state(state_value) \
- smp_store_mb(current->__state, (state_value))
+ do { \
+ debug_normal_state_change((state_value)); \
+ smp_store_mb(current->__state, (state_value)); \
+ } while (0)

/*
* set_special_state() should be used for those states when the blocking task
* can not use the regular condition based wait-loop. In that case we must
- * serialize against wakeups such that any possible in-flight TASK_RUNNING stores
- * will not collide with our state change.
+ * serialize against wakeups such that any possible in-flight TASK_RUNNING
+ * stores will not collide with our state change.
*/
#define set_special_state(state_value) \
do { \
unsigned long flags; /* may shadow */ \
+ \
raw_spin_lock_irqsave(&current->pi_lock, flags); \
+ debug_special_state_change((state_value)); \
WRITE_ONCE(current->__state, (state_value)); \
raw_spin_unlock_irqrestore(&current->pi_lock, flags); \
} while (0)

-#endif
-
#define get_current_state() READ_ONCE(current->__state)

/* Task command name length: */