Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/l…

…inux/kernel/git/tip/linux-2.6-tip

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (24 commits)
  sched: Cleanup duplicate local variable in [enqueue|dequeue]_task_fair
  sched: Replace use of entity_key()
  sched: Separate group-scheduling code more clearly
  sched: Reorder root_domain to remove 64 bit alignment padding
  sched: Do not attempt to destroy uninitialized rt_bandwidth
  sched: Remove unused function cpu_cfs_rq()
  sched: Fix (harmless) typo 'CONFG_FAIR_GROUP_SCHED'
  sched, cgroup: Optimize load_balance_fair()
  sched: Don't update shares twice on on_rq parent
  sched: update correct entity's runtime in check_preempt_wakeup()
  xtensa: Use generic config PREEMPT definition
  h8300: Use generic config PREEMPT definition
  m32r: Use generic PREEMPT config
  sched: Skip autogroup when looking for all rt sched groups
  sched: Simplify mutex_spin_on_owner()
  sched: Remove rcu_read_lock() from wake_affine()
  sched: Generalize sleep inside spinlock detection
  sched: Make sleeping inside spinlock detection working in !CONFIG_PREEMPT
  sched: Isolate preempt counting in its own config option
  sched: Remove pointless in_atomic() definition check
  ...

Documentation/DocBook/kernel-hacking.tmpl

@@ -409,7 +409,7 @@ cond_resched(); /* Will sleep */
 
   <para>
    You should always compile your kernel
-   <symbol>CONFIG_DEBUG_SPINLOCK_SLEEP</symbol> on, and it will warn
+   <symbol>CONFIG_DEBUG_ATOMIC_SLEEP</symbol> on, and it will warn
    you if you break these rules.  If you <emphasis>do</emphasis> break
    the rules, you will eventually lock up your box.
   </para>

Documentation/SubmitChecklist

@@ -53,7 +53,7 @@ kernel patches.
 
 12: Has been tested with CONFIG_PREEMPT, CONFIG_DEBUG_PREEMPT,
     CONFIG_DEBUG_SLAB, CONFIG_DEBUG_PAGEALLOC, CONFIG_DEBUG_MUTEXES,
-    CONFIG_DEBUG_SPINLOCK, CONFIG_DEBUG_SPINLOCK_SLEEP all simultaneously
+    CONFIG_DEBUG_SPINLOCK, CONFIG_DEBUG_ATOMIC_SLEEP all simultaneously
     enabled.
 
 13: Has been build- and runtime tested with and without CONFIG_SMP and

Documentation/development-process/4.Coding

@@ -244,7 +244,7 @@ testing purposes.  In particular, you should turn on:
  - DEBUG_SLAB can find a variety of memory allocation and use errors; it
    should be used on most development kernels.
 
- - DEBUG_SPINLOCK, DEBUG_SPINLOCK_SLEEP, and DEBUG_MUTEXES will find a
+ - DEBUG_SPINLOCK, DEBUG_ATOMIC_SLEEP, and DEBUG_MUTEXES will find a
    number of common locking errors.
 
 There are quite a few other debugging options, some of which will be

Documentation/ja_JP/SubmitChecklist

@@ -68,7 +68,7 @@ Linux カーネルパッチ投稿者向けチェックリスト
 
 12: CONFIG_PREEMPT, CONFIG_DEBUG_PREEMPT, CONFIG_DEBUG_SLAB,
     CONFIG_DEBUG_PAGEALLOC, CONFIG_DEBUG_MUTEXES, CONFIG_DEBUG_SPINLOCK,
-    CONFIG_DEBUG_SPINLOCK_SLEEP これら全てを同時に有効にして動作確認を
+    CONFIG_DEBUG_ATOMIC_SLEEP これら全てを同時に有効にして動作確認を
     行ってください。
 
 13: CONFIG_SMP, CONFIG_PREEMPT を有効にした場合と無効にした場合の両方で

Documentation/zh_CN/SubmitChecklist

@@ -67,7 +67,7 @@ Linux
 
 12���Ѿ�ͨ��CONFIG_PREEMPT, CONFIG_DEBUG_PREEMPT,
     CONFIG_DEBUG_SLAB, CONFIG_DEBUG_PAGEALLOC, CONFIG_DEBUG_MUTEXES,
-    CONFIG_DEBUG_SPINLOCK, CONFIG_DEBUG_SPINLOCK_SLEEP���ԣ�����ͬʱ��
+    CONFIG_DEBUG_SPINLOCK, CONFIG_DEBUG_ATOMIC_SLEEP���ԣ�����ͬʱ��
     ʹ�ܡ�
 
 13���Ѿ�����������ʹ�û��߲�ʹ�� CONFIG_SMP �� CONFIG_PREEMPT����ִ��ʱ�䡣

arch/h8300/Kconfig.cpu

@@ -162,9 +162,7 @@ config H8300_TPU_CH
 	int "TPU channel"
 	depends on H8300_TPU
 
-config PREEMPT
-	bool "Preemptible Kernel"
-	default n
+source "kernel/Kconfig.preempt"
 
 source "mm/Kconfig"
 

arch/m32r/Kconfig

@@ -268,17 +268,7 @@ config SCHED_OMIT_FRAME_POINTER
         bool
         default y
 
-config PREEMPT
-	bool "Preemptible Kernel"
-	help
-	  This option reduces the latency of the kernel when reacting to
-	  real-time or interactive events by allowing a low priority process to
-	  be preempted even if it is in kernel mode executing a system call.
-	  This allows applications to run more reliably even when the system is
-	  under load.
-
-	  Say Y here if you are building a kernel for a desktop, embedded
-	  or real-time system.  Say N if you are unsure.
+source "kernel/Kconfig.preempt"
 
 config SMP
 	bool "Symmetric multi-processing support"

arch/xtensa/Kconfig

@@ -80,18 +80,7 @@ config XTENSA_UNALIGNED_USER
 
 	  Say Y here to enable unaligned memory access in user space.
 
-config PREEMPT
-	bool "Preemptible Kernel"
-	help
-          This option reduces the latency of the kernel when reacting to
-          real-time or interactive events by allowing a low priority process to
-          be preempted even if it is in kernel mode executing a system call.
-          Unfortunately the kernel code has some race conditions if both
-          CONFIG_SMP and CONFIG_PREEMPT are enabled, so this option is
-          currently disabled if you are building an SMP kernel.
-
-          Say Y here if you are building a kernel for a desktop, embedded
-          or real-time system.  Say N if you are unsure.
+source "kernel/Kconfig.preempt"
 
 config MATH_EMULATION
 	bool "Math emulation"

include/linux/bit_spinlock.h

@@ -88,7 +88,7 @@ static inline int bit_spin_is_locked(int bitnum, unsigned long *addr)
 {
 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 	return test_bit(bitnum, addr);
-#elif defined CONFIG_PREEMPT
+#elif defined CONFIG_PREEMPT_COUNT
 	return preempt_count();
 #else
 	return 1;

include/linux/hardirq.h

@@ -93,7 +93,7 @@
  */
 #define in_nmi()	(preempt_count() & NMI_MASK)
 
-#if defined(CONFIG_PREEMPT)
+#if defined(CONFIG_PREEMPT_COUNT)
 # define PREEMPT_CHECK_OFFSET 1
 #else
 # define PREEMPT_CHECK_OFFSET 0
@@ -115,7 +115,7 @@
 #define in_atomic_preempt_off() \
 		((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_CHECK_OFFSET)
 
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPT_COUNT
 # define preemptible()	(preempt_count() == 0 && !irqs_disabled())
 # define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1)
 #else

include/linux/kernel.h

@@ -121,7 +121,7 @@ extern int _cond_resched(void);
 # define might_resched() do { } while (0)
 #endif
 
-#ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
+#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
   void __might_sleep(const char *file, int line, int preempt_offset);
 /**
  * might_sleep - annotation for functions that can sleep

include/linux/pagemap.h

@@ -134,7 +134,7 @@ static inline int page_cache_get_speculative(struct page *page)
 	VM_BUG_ON(in_interrupt());
 
 #if !defined(CONFIG_SMP) && defined(CONFIG_TREE_RCU)
-# ifdef CONFIG_PREEMPT
+# ifdef CONFIG_PREEMPT_COUNT
 	VM_BUG_ON(!in_atomic());
 # endif
 	/*
@@ -172,7 +172,7 @@ static inline int page_cache_add_speculative(struct page *page, int count)
 	VM_BUG_ON(in_interrupt());
 
 #if !defined(CONFIG_SMP) && defined(CONFIG_TREE_RCU)
-# ifdef CONFIG_PREEMPT
+# ifdef CONFIG_PREEMPT_COUNT
 	VM_BUG_ON(!in_atomic());
 # endif
 	VM_BUG_ON(page_count(page) == 0);

include/linux/preempt.h

@@ -27,6 +27,21 @@
 
 asmlinkage void preempt_schedule(void);
 
+#define preempt_check_resched() \
+do { \
+	if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) \
+		preempt_schedule(); \
+} while (0)
+
+#else /* !CONFIG_PREEMPT */
+
+#define preempt_check_resched()		do { } while (0)
+
+#endif /* CONFIG_PREEMPT */
+
+
+#ifdef CONFIG_PREEMPT_COUNT
+
 #define preempt_disable() \
 do { \
 	inc_preempt_count(); \
@@ -39,12 +54,6 @@ do { \
 	dec_preempt_count(); \
 } while (0)
 
-#define preempt_check_resched() \
-do { \
-	if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) \
-		preempt_schedule(); \
-} while (0)
-
 #define preempt_enable() \
 do { \
 	preempt_enable_no_resched(); \
@@ -80,18 +89,17 @@ do { \
 	preempt_check_resched(); \
 } while (0)
 
-#else
+#else /* !CONFIG_PREEMPT_COUNT */
 
 #define preempt_disable()		do { } while (0)
 #define preempt_enable_no_resched()	do { } while (0)
 #define preempt_enable()		do { } while (0)
-#define preempt_check_resched()		do { } while (0)
 
 #define preempt_disable_notrace()		do { } while (0)
 #define preempt_enable_no_resched_notrace()	do { } while (0)
 #define preempt_enable_notrace()		do { } while (0)
 
-#endif
+#endif /* CONFIG_PREEMPT_COUNT */
 
 #ifdef CONFIG_PREEMPT_NOTIFIERS
 

include/linux/rcupdate.h

@@ -239,7 +239,7 @@ extern int rcu_read_lock_bh_held(void);
  * Check debug_lockdep_rcu_enabled() to prevent false positives during boot
  * and while lockdep is disabled.
  */
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPT_COUNT
 static inline int rcu_read_lock_sched_held(void)
 {
 	int lockdep_opinion = 0;
@@ -250,12 +250,12 @@ static inline int rcu_read_lock_sched_held(void)
 		lockdep_opinion = lock_is_held(&rcu_sched_lock_map);
 	return lockdep_opinion || preempt_count() != 0 || irqs_disabled();
 }
-#else /* #ifdef CONFIG_PREEMPT */
+#else /* #ifdef CONFIG_PREEMPT_COUNT */
 static inline int rcu_read_lock_sched_held(void)
 {
 	return 1;
 }
-#endif /* #else #ifdef CONFIG_PREEMPT */
+#endif /* #else #ifdef CONFIG_PREEMPT_COUNT */
 
 #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
 
@@ -276,17 +276,17 @@ static inline int rcu_read_lock_bh_held(void)
 	return 1;
 }
 
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPT_COUNT
 static inline int rcu_read_lock_sched_held(void)
 {
 	return preempt_count() != 0 || irqs_disabled();
 }
-#else /* #ifdef CONFIG_PREEMPT */
+#else /* #ifdef CONFIG_PREEMPT_COUNT */
 static inline int rcu_read_lock_sched_held(void)
 {
 	return 1;
 }
-#endif /* #else #ifdef CONFIG_PREEMPT */
+#endif /* #else #ifdef CONFIG_PREEMPT_COUNT */
 
 #endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
 

include/linux/sched.h

@@ -2526,7 +2526,7 @@ extern int _cond_resched(void);
 
 extern int __cond_resched_lock(spinlock_t *lock);
 
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPT_COUNT
 #define PREEMPT_LOCK_OFFSET	PREEMPT_OFFSET
 #else
 #define PREEMPT_LOCK_OFFSET	0

kernel/Kconfig.preempt

@@ -35,6 +35,7 @@ config PREEMPT_VOLUNTARY
 
 config PREEMPT
 	bool "Preemptible Kernel (Low-Latency Desktop)"
+	select PREEMPT_COUNT
 	help
 	  This option reduces the latency of the kernel by making
 	  all kernel code (that is not executing in a critical section)
@@ -52,3 +53,5 @@ config PREEMPT
 
 endchoice
 
+config PREEMPT_COUNT
+       bool