linux-kernel - [patch V3 03/64] sched: Reorganize current::_

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Date:   Thu, 05 Aug 2021 17:13:03 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>,
        Juri Lelli <juri.lelli@...hat.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Daniel Bristot de Oliveira <bristot@...hat.com>,
        Will Deacon <will@...nel.org>,
        Waiman Long <longman@...hat.com>,
        Boqun Feng <boqun.feng@...il.com>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Davidlohr Bueso <dave@...olabs.net>,
        Mike Galbraith <efault@....de>
Subject: [patch V3 03/64] sched: Reorganize current::__state helpers

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@...hat.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.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: */