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Date:	Wed, 16 Oct 2013 20:38:18 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Christoph Lameter <cl@...ux.com>
Cc:	Tejun Heo <tj@...nel.org>, akpm@...uxfoundation.org,
	rostedt@...dmis.org, linux-kernel@...r.kernel.org,
	Ingo Molnar <mingo@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH 6/6] percpu: Add preemption checks to __this_cpu ops

On Wed, Oct 16, 2013 at 06:25:37PM +0200, Peter Zijlstra wrote:
> To rename __this_cpu to raw_cpu; it would then need a little manual
> fixup and generic __this_cpu -> raW_cpu map, which can add the
> preemption check.

Something like so perhaps... only lightly compile tested
(x86_64-defconfig).

---
 arch/x86/include/asm/percpu.h  | 108 ++++++------
 arch/x86/include/asm/preempt.h |  16 +-
 include/asm-generic/percpu.h   |  15 +-
 include/linux/percpu.h         | 385 +++++++++++++++++++++++++----------------
 lib/smp_processor_id.c         |  19 +-
 5 files changed, 319 insertions(+), 224 deletions(-)

diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h
index 0da5200..a053103 100644
--- a/arch/x86/include/asm/percpu.h
+++ b/arch/x86/include/asm/percpu.h
@@ -52,7 +52,7 @@
  * Compared to the generic __my_cpu_offset version, the following
  * saves one instruction and avoids clobbering a temp register.
  */
-#define __this_cpu_ptr(ptr)				\
+#define raw_cpu_ptr(ptr)				\
 ({							\
 	unsigned long tcp_ptr__;			\
 	__verify_pcpu_ptr(ptr);				\
@@ -361,28 +361,28 @@ do {									\
  */
 #define this_cpu_read_stable(var)	percpu_from_op("mov", var, "p" (&(var)))
 
-#define __this_cpu_read_1(pcp)		percpu_from_op("mov", (pcp), "m"(pcp))
-#define __this_cpu_read_2(pcp)		percpu_from_op("mov", (pcp), "m"(pcp))
-#define __this_cpu_read_4(pcp)		percpu_from_op("mov", (pcp), "m"(pcp))
-
-#define __this_cpu_write_1(pcp, val)	percpu_to_op("mov", (pcp), val)
-#define __this_cpu_write_2(pcp, val)	percpu_to_op("mov", (pcp), val)
-#define __this_cpu_write_4(pcp, val)	percpu_to_op("mov", (pcp), val)
-#define __this_cpu_add_1(pcp, val)	percpu_add_op((pcp), val)
-#define __this_cpu_add_2(pcp, val)	percpu_add_op((pcp), val)
-#define __this_cpu_add_4(pcp, val)	percpu_add_op((pcp), val)
-#define __this_cpu_and_1(pcp, val)	percpu_to_op("and", (pcp), val)
-#define __this_cpu_and_2(pcp, val)	percpu_to_op("and", (pcp), val)
-#define __this_cpu_and_4(pcp, val)	percpu_to_op("and", (pcp), val)
-#define __this_cpu_or_1(pcp, val)	percpu_to_op("or", (pcp), val)
-#define __this_cpu_or_2(pcp, val)	percpu_to_op("or", (pcp), val)
-#define __this_cpu_or_4(pcp, val)	percpu_to_op("or", (pcp), val)
-#define __this_cpu_xor_1(pcp, val)	percpu_to_op("xor", (pcp), val)
-#define __this_cpu_xor_2(pcp, val)	percpu_to_op("xor", (pcp), val)
-#define __this_cpu_xor_4(pcp, val)	percpu_to_op("xor", (pcp), val)
-#define __this_cpu_xchg_1(pcp, val)	percpu_xchg_op(pcp, val)
-#define __this_cpu_xchg_2(pcp, val)	percpu_xchg_op(pcp, val)
-#define __this_cpu_xchg_4(pcp, val)	percpu_xchg_op(pcp, val)
+#define raw_cpu_read_1(pcp)		percpu_from_op("mov", (pcp), "m"(pcp))
+#define raw_cpu_read_2(pcp)		percpu_from_op("mov", (pcp), "m"(pcp))
+#define raw_cpu_read_4(pcp)		percpu_from_op("mov", (pcp), "m"(pcp))
+
+#define raw_cpu_write_1(pcp, val)	percpu_to_op("mov", (pcp), val)
+#define raw_cpu_write_2(pcp, val)	percpu_to_op("mov", (pcp), val)
+#define raw_cpu_write_4(pcp, val)	percpu_to_op("mov", (pcp), val)
+#define raw_cpu_add_1(pcp, val)		percpu_add_op((pcp), val)
+#define raw_cpu_add_2(pcp, val)		percpu_add_op((pcp), val)
+#define raw_cpu_add_4(pcp, val)		percpu_add_op((pcp), val)
+#define raw_cpu_and_1(pcp, val)		percpu_to_op("and", (pcp), val)
+#define raw_cpu_and_2(pcp, val)		percpu_to_op("and", (pcp), val)
+#define raw_cpu_and_4(pcp, val)		percpu_to_op("and", (pcp), val)
+#define raw_cpu_or_1(pcp, val)		percpu_to_op("or", (pcp), val)
+#define raw_cpu_or_2(pcp, val)		percpu_to_op("or", (pcp), val)
+#define raw_cpu_or_4(pcp, val)		percpu_to_op("or", (pcp), val)
+#define raw_cpu_xor_1(pcp, val)		percpu_to_op("xor", (pcp), val)
+#define raw_cpu_xor_2(pcp, val)		percpu_to_op("xor", (pcp), val)
+#define raw_cpu_xor_4(pcp, val)		percpu_to_op("xor", (pcp), val)
+#define raw_cpu_xchg_1(pcp, val)	percpu_xchg_op(pcp, val)
+#define raw_cpu_xchg_2(pcp, val)	percpu_xchg_op(pcp, val)
+#define raw_cpu_xchg_4(pcp, val)	percpu_xchg_op(pcp, val)
 
 #define this_cpu_read_1(pcp)		percpu_from_op("mov", (pcp), "m"(pcp))
 #define this_cpu_read_2(pcp)		percpu_from_op("mov", (pcp), "m"(pcp))
@@ -406,16 +406,16 @@ do {									\
 #define this_cpu_xchg_2(pcp, nval)	percpu_xchg_op(pcp, nval)
 #define this_cpu_xchg_4(pcp, nval)	percpu_xchg_op(pcp, nval)
 
-#define __this_cpu_add_return_1(pcp, val) percpu_add_return_op(pcp, val)
-#define __this_cpu_add_return_2(pcp, val) percpu_add_return_op(pcp, val)
-#define __this_cpu_add_return_4(pcp, val) percpu_add_return_op(pcp, val)
-#define __this_cpu_cmpxchg_1(pcp, oval, nval)	percpu_cmpxchg_op(pcp, oval, nval)
-#define __this_cpu_cmpxchg_2(pcp, oval, nval)	percpu_cmpxchg_op(pcp, oval, nval)
-#define __this_cpu_cmpxchg_4(pcp, oval, nval)	percpu_cmpxchg_op(pcp, oval, nval)
+#define raw_cpu_add_return_1(pcp, val)		percpu_add_return_op(pcp, val)
+#define raw_cpu_add_return_2(pcp, val)		percpu_add_return_op(pcp, val)
+#define raw_cpu_add_return_4(pcp, val)		percpu_add_return_op(pcp, val)
+#define raw_cpu_cmpxchg_1(pcp, oval, nval)	percpu_cmpxchg_op(pcp, oval, nval)
+#define raw_cpu_cmpxchg_2(pcp, oval, nval)	percpu_cmpxchg_op(pcp, oval, nval)
+#define raw_cpu_cmpxchg_4(pcp, oval, nval)	percpu_cmpxchg_op(pcp, oval, nval)
 
-#define this_cpu_add_return_1(pcp, val)	percpu_add_return_op(pcp, val)
-#define this_cpu_add_return_2(pcp, val)	percpu_add_return_op(pcp, val)
-#define this_cpu_add_return_4(pcp, val)	percpu_add_return_op(pcp, val)
+#define this_cpu_add_return_1(pcp, val)		percpu_add_return_op(pcp, val)
+#define this_cpu_add_return_2(pcp, val)		percpu_add_return_op(pcp, val)
+#define this_cpu_add_return_4(pcp, val)		percpu_add_return_op(pcp, val)
 #define this_cpu_cmpxchg_1(pcp, oval, nval)	percpu_cmpxchg_op(pcp, oval, nval)
 #define this_cpu_cmpxchg_2(pcp, oval, nval)	percpu_cmpxchg_op(pcp, oval, nval)
 #define this_cpu_cmpxchg_4(pcp, oval, nval)	percpu_cmpxchg_op(pcp, oval, nval)
@@ -432,7 +432,7 @@ do {									\
 	__ret;								\
 })
 
-#define __this_cpu_cmpxchg_double_4	percpu_cmpxchg8b_double
+#define raw_cpu_cmpxchg_double_4	percpu_cmpxchg8b_double
 #define this_cpu_cmpxchg_double_4	percpu_cmpxchg8b_double
 #endif /* CONFIG_X86_CMPXCHG64 */
 
@@ -441,24 +441,24 @@ do {									\
  * 32 bit must fall back to generic operations.
  */
 #ifdef CONFIG_X86_64
-#define __this_cpu_read_8(pcp)		percpu_from_op("mov", (pcp), "m"(pcp))
-#define __this_cpu_write_8(pcp, val)	percpu_to_op("mov", (pcp), val)
-#define __this_cpu_add_8(pcp, val)	percpu_add_op((pcp), val)
-#define __this_cpu_and_8(pcp, val)	percpu_to_op("and", (pcp), val)
-#define __this_cpu_or_8(pcp, val)	percpu_to_op("or", (pcp), val)
-#define __this_cpu_xor_8(pcp, val)	percpu_to_op("xor", (pcp), val)
-#define __this_cpu_add_return_8(pcp, val) percpu_add_return_op(pcp, val)
-#define __this_cpu_xchg_8(pcp, nval)	percpu_xchg_op(pcp, nval)
-#define __this_cpu_cmpxchg_8(pcp, oval, nval)	percpu_cmpxchg_op(pcp, oval, nval)
-
-#define this_cpu_read_8(pcp)		percpu_from_op("mov", (pcp), "m"(pcp))
-#define this_cpu_write_8(pcp, val)	percpu_to_op("mov", (pcp), val)
-#define this_cpu_add_8(pcp, val)	percpu_add_op((pcp), val)
-#define this_cpu_and_8(pcp, val)	percpu_to_op("and", (pcp), val)
-#define this_cpu_or_8(pcp, val)		percpu_to_op("or", (pcp), val)
-#define this_cpu_xor_8(pcp, val)	percpu_to_op("xor", (pcp), val)
-#define this_cpu_add_return_8(pcp, val)	percpu_add_return_op(pcp, val)
-#define this_cpu_xchg_8(pcp, nval)	percpu_xchg_op(pcp, nval)
+#define raw_cpu_read_8(pcp)			percpu_from_op("mov", (pcp), "m"(pcp))
+#define raw_cpu_write_8(pcp, val)		percpu_to_op("mov", (pcp), val)
+#define raw_cpu_add_8(pcp, val)			percpu_add_op((pcp), val)
+#define raw_cpu_and_8(pcp, val)			percpu_to_op("and", (pcp), val)
+#define raw_cpu_or_8(pcp, val)			percpu_to_op("or", (pcp), val)
+#define raw_cpu_xor_8(pcp, val)			percpu_to_op("xor", (pcp), val)
+#define raw_cpu_add_return_8(pcp, val)		percpu_add_return_op(pcp, val)
+#define raw_cpu_xchg_8(pcp, nval)		percpu_xchg_op(pcp, nval)
+#define raw_cpu_cmpxchg_8(pcp, oval, nval)	percpu_cmpxchg_op(pcp, oval, nval)
+
+#define this_cpu_read_8(pcp)			percpu_from_op("mov", (pcp), "m"(pcp))
+#define this_cpu_write_8(pcp, val)		percpu_to_op("mov", (pcp), val)
+#define this_cpu_add_8(pcp, val)		percpu_add_op((pcp), val)
+#define this_cpu_and_8(pcp, val)		percpu_to_op("and", (pcp), val)
+#define this_cpu_or_8(pcp, val)			percpu_to_op("or", (pcp), val)
+#define this_cpu_xor_8(pcp, val)		percpu_to_op("xor", (pcp), val)
+#define this_cpu_add_return_8(pcp, val)		percpu_add_return_op(pcp, val)
+#define this_cpu_xchg_8(pcp, nval)		percpu_xchg_op(pcp, nval)
 #define this_cpu_cmpxchg_8(pcp, oval, nval)	percpu_cmpxchg_op(pcp, oval, nval)
 
 /*
@@ -481,7 +481,7 @@ do {									\
 	__ret;								\
 })
 
-#define __this_cpu_cmpxchg_double_8	percpu_cmpxchg16b_double
+#define raw_cpu_cmpxchg_double_8	percpu_cmpxchg16b_double
 #define this_cpu_cmpxchg_double_8	percpu_cmpxchg16b_double
 
 #endif
@@ -502,9 +502,9 @@ static __always_inline int x86_this_cpu_constant_test_bit(unsigned int nr,
 	unsigned long __percpu *a = (unsigned long *)addr + nr / BITS_PER_LONG;
 
 #ifdef CONFIG_X86_64
-	return ((1UL << (nr % BITS_PER_LONG)) & __this_cpu_read_8(*a)) != 0;
+	return ((1UL << (nr % BITS_PER_LONG)) & raw_cpu_read_8(*a)) != 0;
 #else
-	return ((1UL << (nr % BITS_PER_LONG)) & __this_cpu_read_4(*a)) != 0;
+	return ((1UL << (nr % BITS_PER_LONG)) & raw_cpu_read_4(*a)) != 0;
 #endif
 }
 
diff --git a/arch/x86/include/asm/preempt.h b/arch/x86/include/asm/preempt.h
index 8729723..95e3532 100644
--- a/arch/x86/include/asm/preempt.h
+++ b/arch/x86/include/asm/preempt.h
@@ -13,12 +13,12 @@ DECLARE_PER_CPU(int, __preempt_count);
  */
 static __always_inline int preempt_count(void)
 {
-	return __this_cpu_read_4(__preempt_count) & ~PREEMPT_NEED_RESCHED;
+	return raw_cpu_read_4(__preempt_count) & ~PREEMPT_NEED_RESCHED;
 }
 
 static __always_inline void preempt_count_set(int pc)
 {
-	__this_cpu_write_4(__preempt_count, pc);
+	raw_cpu_write_4(__preempt_count, pc);
 }
 
 /*
@@ -47,17 +47,17 @@ static __always_inline void preempt_count_set(int pc)
 
 static __always_inline void set_preempt_need_resched(void)
 {
-	__this_cpu_and_4(__preempt_count, ~PREEMPT_NEED_RESCHED);
+	raw_cpu_and_4(__preempt_count, ~PREEMPT_NEED_RESCHED);
 }
 
 static __always_inline void clear_preempt_need_resched(void)
 {
-	__this_cpu_or_4(__preempt_count, PREEMPT_NEED_RESCHED);
+	raw_cpu_or_4(__preempt_count, PREEMPT_NEED_RESCHED);
 }
 
 static __always_inline bool test_preempt_need_resched(void)
 {
-	return !(__this_cpu_read_4(__preempt_count) & PREEMPT_NEED_RESCHED);
+	return !(raw_cpu_read_4(__preempt_count) & PREEMPT_NEED_RESCHED);
 }
 
 /*
@@ -66,12 +66,12 @@ static __always_inline bool test_preempt_need_resched(void)
 
 static __always_inline void __preempt_count_add(int val)
 {
-	__this_cpu_add_4(__preempt_count, val);
+	raw_cpu_add_4(__preempt_count, val);
 }
 
 static __always_inline void __preempt_count_sub(int val)
 {
-	__this_cpu_add_4(__preempt_count, -val);
+	raw_cpu_add_4(__preempt_count, -val);
 }
 
 static __always_inline bool __preempt_count_dec_and_test(void)
@@ -84,7 +84,7 @@ static __always_inline bool __preempt_count_dec_and_test(void)
  */
 static __always_inline bool should_resched(void)
 {
-	return unlikely(!__this_cpu_read_4(__preempt_count));
+	return unlikely(!raw_cpu_read_4(__preempt_count));
 }
 
 #ifdef CONFIG_PREEMPT
diff --git a/include/asm-generic/percpu.h b/include/asm-generic/percpu.h
index d17784e..b5aca54 100644
--- a/include/asm-generic/percpu.h
+++ b/include/asm-generic/percpu.h
@@ -56,17 +56,18 @@ extern unsigned long __per_cpu_offset[NR_CPUS];
 #define per_cpu(var, cpu) \
 	(*SHIFT_PERCPU_PTR(&(var), per_cpu_offset(cpu)))
 
-#ifndef __this_cpu_ptr
-#define __this_cpu_ptr(ptr) SHIFT_PERCPU_PTR(ptr, __my_cpu_offset)
+#ifndef raw_cpu_ptr
+#define raw_cpu_ptr(ptr) SHIFT_PERCPU_PTR(ptr, __my_cpu_offset)
 #endif
+
 #ifdef CONFIG_DEBUG_PREEMPT
 #define this_cpu_ptr(ptr) SHIFT_PERCPU_PTR(ptr, my_cpu_offset)
 #else
-#define this_cpu_ptr(ptr) __this_cpu_ptr(ptr)
+#define this_cpu_ptr(ptr) raw_cpu_ptr(ptr)
 #endif
 
-#define __get_cpu_var(var) (*this_cpu_ptr(&(var)))
-#define __raw_get_cpu_var(var) (*__this_cpu_ptr(&(var)))
+#define __get_cpu_var(var)	(*this_cpu_ptr(&(var)))
+#define __raw_get_cpu_var(var)	(*raw_cpu_ptr(&(var)))
 
 #ifdef CONFIG_HAVE_SETUP_PER_CPU_AREA
 extern void setup_per_cpu_areas(void);
@@ -83,10 +84,12 @@ extern void setup_per_cpu_areas(void);
 #define __get_cpu_var(var)	(*VERIFY_PERCPU_PTR(&(var)))
 #define __raw_get_cpu_var(var)	(*VERIFY_PERCPU_PTR(&(var)))
 #define this_cpu_ptr(ptr)	per_cpu_ptr(ptr, 0)
-#define __this_cpu_ptr(ptr)	this_cpu_ptr(ptr)
+#define raw_cpu_ptr(ptr)	this_cpu_ptr(ptr)
 
 #endif	/* SMP */
 
+#define __this_cpu_ptr(ptr)	this_cpu_ptr(ptr)
+
 #ifndef PER_CPU_BASE_SECTION
 #ifdef CONFIG_SMP
 #define PER_CPU_BASE_SECTION ".data..percpu"
diff --git a/include/linux/percpu.h b/include/linux/percpu.h
index cc88172..b88f03f 100644
--- a/include/linux/percpu.h
+++ b/include/linux/percpu.h
@@ -295,7 +295,7 @@ do {									\
 do {									\
 	unsigned long flags;						\
 	raw_local_irq_save(flags);					\
-	*__this_cpu_ptr(&(pcp)) op val;					\
+	*raw_cpu_ptr(&(pcp)) op val;					\
 	raw_local_irq_restore(flags);					\
 } while (0)
 
@@ -396,8 +396,8 @@ do {									\
 	typeof(pcp) ret__;						\
 	unsigned long flags;						\
 	raw_local_irq_save(flags);					\
-	__this_cpu_add(pcp, val);					\
-	ret__ = __this_cpu_read(pcp);					\
+	raw_cpu_add(pcp, val);					\
+	ret__ = raw_cpu_read(pcp);					\
 	raw_local_irq_restore(flags);					\
 	ret__;								\
 })
@@ -426,8 +426,8 @@ do {									\
 ({	typeof(pcp) ret__;						\
 	unsigned long flags;						\
 	raw_local_irq_save(flags);					\
-	ret__ = __this_cpu_read(pcp);					\
-	__this_cpu_write(pcp, nval);					\
+	ret__ = raw_cpu_read(pcp);					\
+	raw_cpu_write(pcp, nval);					\
 	raw_local_irq_restore(flags);					\
 	ret__;								\
 })
@@ -454,9 +454,9 @@ do {									\
 	typeof(pcp) ret__;						\
 	unsigned long flags;						\
 	raw_local_irq_save(flags);					\
-	ret__ = __this_cpu_read(pcp);					\
+	ret__ = raw_cpu_read(pcp);					\
 	if (ret__ == (oval))						\
-		__this_cpu_write(pcp, nval);				\
+		raw_cpu_write(pcp, nval);				\
 	raw_local_irq_restore(flags);					\
 	ret__;								\
 })
@@ -491,7 +491,7 @@ do {									\
 	int ret__;							\
 	unsigned long flags;						\
 	raw_local_irq_save(flags);					\
-	ret__ = __this_cpu_generic_cmpxchg_double(pcp1, pcp2,		\
+	ret__ = raw_cpu_generic_cmpxchg_double(pcp1, pcp2,		\
 			oval1, oval2, nval1, nval2);			\
 	raw_local_irq_restore(flags);					\
 	ret__;								\
@@ -519,240 +519,321 @@ do {									\
 #endif
 
 /*
- * Generic percpu operations for context that are safe from preemption/interrupts.
- * Either we do not care about races or the caller has the
- * responsibility of handling preemption/interrupt issues. Arch code can still
- * override these instructions since the arch per cpu code may be more
- * efficient and may actually get race freeness for free (that is the
- * case for x86 for example).
+ * Generic percpu operations for context where we do not want to do any checks
+ * for preemptiosn.
+ *
+ * If there is no other protection through preempt disable and/or disabling
+ * interupts then one of these RMW operations can show unexpected behavior
+ * because the execution thread was rescheduled on another processor or an
+ * interrupt occurred and the same percpu variable was modified from the
+ * interrupt context.
  *
- * If there is no other protection through preempt disable and/or
- * disabling interupts then one of these RMW operations can show unexpected
- * behavior because the execution thread was rescheduled on another processor
- * or an interrupt occurred and the same percpu variable was modified from
- * the interrupt context.
+ * Use with care!
  */
-#ifndef __this_cpu_read
-# ifndef __this_cpu_read_1
-#  define __this_cpu_read_1(pcp)	(*__this_cpu_ptr(&(pcp)))
+#ifndef raw_cpu_read
+# ifndef raw_cpu_read_1
+#  define raw_cpu_read_1(pcp)	(*raw_cpu_ptr(&(pcp)))
 # endif
-# ifndef __this_cpu_read_2
-#  define __this_cpu_read_2(pcp)	(*__this_cpu_ptr(&(pcp)))
+# ifndef raw_cpu_read_2
+#  define raw_cpu_read_2(pcp)	(*raw_cpu_ptr(&(pcp)))
 # endif
-# ifndef __this_cpu_read_4
-#  define __this_cpu_read_4(pcp)	(*__this_cpu_ptr(&(pcp)))
+# ifndef raw_cpu_read_4
+#  define raw_cpu_read_4(pcp)	(*raw_cpu_ptr(&(pcp)))
 # endif
-# ifndef __this_cpu_read_8
-#  define __this_cpu_read_8(pcp)	(*__this_cpu_ptr(&(pcp)))
+# ifndef raw_cpu_read_8
+#  define raw_cpu_read_8(pcp)	(*raw_cpu_ptr(&(pcp)))
 # endif
-# define __this_cpu_read(pcp)	__pcpu_size_call_return(__this_cpu_read_, (pcp))
+# define raw_cpu_read(pcp)	__pcpu_size_call_return(raw_cpu_read_, (pcp))
 #endif
 
-#define __this_cpu_generic_to_op(pcp, val, op)				\
+#define raw_cpu_generic_to_op(pcp, val, op)				\
 do {									\
-	*__this_cpu_ptr(&(pcp)) op val;					\
+	*raw_cpu_ptr(&(pcp)) op val;					\
 } while (0)
 
-#ifndef __this_cpu_write
-# ifndef __this_cpu_write_1
-#  define __this_cpu_write_1(pcp, val)	__this_cpu_generic_to_op((pcp), (val), =)
+#ifndef raw_cpu_write
+# ifndef raw_cpu_write_1
+#  define raw_cpu_write_1(pcp, val)	raw_cpu_generic_to_op((pcp), (val), =)
 # endif
-# ifndef __this_cpu_write_2
-#  define __this_cpu_write_2(pcp, val)	__this_cpu_generic_to_op((pcp), (val), =)
+# ifndef raw_cpu_write_2
+#  define raw_cpu_write_2(pcp, val)	raw_cpu_generic_to_op((pcp), (val), =)
 # endif
-# ifndef __this_cpu_write_4
-#  define __this_cpu_write_4(pcp, val)	__this_cpu_generic_to_op((pcp), (val), =)
+# ifndef raw_cpu_write_4
+#  define raw_cpu_write_4(pcp, val)	raw_cpu_generic_to_op((pcp), (val), =)
 # endif
-# ifndef __this_cpu_write_8
-#  define __this_cpu_write_8(pcp, val)	__this_cpu_generic_to_op((pcp), (val), =)
+# ifndef raw_cpu_write_8
+#  define raw_cpu_write_8(pcp, val)	raw_cpu_generic_to_op((pcp), (val), =)
 # endif
-# define __this_cpu_write(pcp, val)	__pcpu_size_call(__this_cpu_write_, (pcp), (val))
+# define raw_cpu_write(pcp, val)	__pcpu_size_call(raw_cpu_write_, (pcp), (val))
 #endif
 
-#ifndef __this_cpu_add
-# ifndef __this_cpu_add_1
-#  define __this_cpu_add_1(pcp, val)	__this_cpu_generic_to_op((pcp), (val), +=)
+#ifndef raw_cpu_add
+# ifndef raw_cpu_add_1
+#  define raw_cpu_add_1(pcp, val)	raw_cpu_generic_to_op((pcp), (val), +=)
 # endif
-# ifndef __this_cpu_add_2
-#  define __this_cpu_add_2(pcp, val)	__this_cpu_generic_to_op((pcp), (val), +=)
+# ifndef raw_cpu_add_2
+#  define raw_cpu_add_2(pcp, val)	raw_cpu_generic_to_op((pcp), (val), +=)
 # endif
-# ifndef __this_cpu_add_4
-#  define __this_cpu_add_4(pcp, val)	__this_cpu_generic_to_op((pcp), (val), +=)
+# ifndef raw_cpu_add_4
+#  define raw_cpu_add_4(pcp, val)	raw_cpu_generic_to_op((pcp), (val), +=)
 # endif
-# ifndef __this_cpu_add_8
-#  define __this_cpu_add_8(pcp, val)	__this_cpu_generic_to_op((pcp), (val), +=)
+# ifndef raw_cpu_add_8
+#  define raw_cpu_add_8(pcp, val)	raw_cpu_generic_to_op((pcp), (val), +=)
 # endif
-# define __this_cpu_add(pcp, val)	__pcpu_size_call(__this_cpu_add_, (pcp), (val))
+# define raw_cpu_add(pcp, val)		__pcpu_size_call(raw_cpu_add_, (pcp), (val))
 #endif
 
-#ifndef __this_cpu_sub
-# define __this_cpu_sub(pcp, val)	__this_cpu_add((pcp), -(val))
+#ifndef raw_cpu_sub
+# define raw_cpu_sub(pcp, val)		raw_cpu_add((pcp), -(val))
 #endif
 
-#ifndef __this_cpu_inc
-# define __this_cpu_inc(pcp)		__this_cpu_add((pcp), 1)
+#ifndef raw_cpu_inc
+# define raw_cpu_inc(pcp)		raw_cpu_add((pcp), 1)
 #endif
 
-#ifndef __this_cpu_dec
-# define __this_cpu_dec(pcp)		__this_cpu_sub((pcp), 1)
+#ifndef raw_cpu_dec
+# define raw_cpu_dec(pcp)		raw_cpu_sub((pcp), 1)
 #endif
 
-#ifndef __this_cpu_and
-# ifndef __this_cpu_and_1
-#  define __this_cpu_and_1(pcp, val)	__this_cpu_generic_to_op((pcp), (val), &=)
+#ifndef raw_cpu_and
+# ifndef raw_cpu_and_1
+#  define raw_cpu_and_1(pcp, val)	raw_cpu_generic_to_op((pcp), (val), &=)
 # endif
-# ifndef __this_cpu_and_2
-#  define __this_cpu_and_2(pcp, val)	__this_cpu_generic_to_op((pcp), (val), &=)
+# ifndef raw_cpu_and_2
+#  define raw_cpu_and_2(pcp, val)	raw_cpu_generic_to_op((pcp), (val), &=)
 # endif
-# ifndef __this_cpu_and_4
-#  define __this_cpu_and_4(pcp, val)	__this_cpu_generic_to_op((pcp), (val), &=)
+# ifndef raw_cpu_and_4
+#  define raw_cpu_and_4(pcp, val)	raw_cpu_generic_to_op((pcp), (val), &=)
 # endif
-# ifndef __this_cpu_and_8
-#  define __this_cpu_and_8(pcp, val)	__this_cpu_generic_to_op((pcp), (val), &=)
+# ifndef raw_cpu_and_8
+#  define raw_cpu_and_8(pcp, val)	raw_cpu_generic_to_op((pcp), (val), &=)
 # endif
-# define __this_cpu_and(pcp, val)	__pcpu_size_call(__this_cpu_and_, (pcp), (val))
+# define raw_cpu_and(pcp, val)		__pcpu_size_call(raw_cpu_and_, (pcp), (val))
 #endif
 
-#ifndef __this_cpu_or
-# ifndef __this_cpu_or_1
-#  define __this_cpu_or_1(pcp, val)	__this_cpu_generic_to_op((pcp), (val), |=)
+#ifndef raw_cpu_or
+# ifndef raw_cpu_or_1
+#  define raw_cpu_or_1(pcp, val)	raw_cpu_generic_to_op((pcp), (val), |=)
 # endif
-# ifndef __this_cpu_or_2
-#  define __this_cpu_or_2(pcp, val)	__this_cpu_generic_to_op((pcp), (val), |=)
+# ifndef raw_cpu_or_2
+#  define raw_cpu_or_2(pcp, val)	raw_cpu_generic_to_op((pcp), (val), |=)
 # endif
-# ifndef __this_cpu_or_4
-#  define __this_cpu_or_4(pcp, val)	__this_cpu_generic_to_op((pcp), (val), |=)
+# ifndef raw_cpu_or_4
+#  define raw_cpu_or_4(pcp, val)	raw_cpu_generic_to_op((pcp), (val), |=)
 # endif
-# ifndef __this_cpu_or_8
-#  define __this_cpu_or_8(pcp, val)	__this_cpu_generic_to_op((pcp), (val), |=)
+# ifndef raw_cpu_or_8
+#  define raw_cpu_or_8(pcp, val)	raw_cpu_generic_to_op((pcp), (val), |=)
 # endif
-# define __this_cpu_or(pcp, val)	__pcpu_size_call(__this_cpu_or_, (pcp), (val))
+# define raw_cpu_or(pcp, val)		__pcpu_size_call(raw_cpu_or_, (pcp), (val))
 #endif
 
-#ifndef __this_cpu_xor
-# ifndef __this_cpu_xor_1
-#  define __this_cpu_xor_1(pcp, val)	__this_cpu_generic_to_op((pcp), (val), ^=)
+#ifndef raw_cpu_xor
+# ifndef raw_cpu_xor_1
+#  define raw_cpu_xor_1(pcp, val)	raw_cpu_generic_to_op((pcp), (val), ^=)
 # endif
-# ifndef __this_cpu_xor_2
-#  define __this_cpu_xor_2(pcp, val)	__this_cpu_generic_to_op((pcp), (val), ^=)
+# ifndef raw_cpu_xor_2
+#  define raw_cpu_xor_2(pcp, val)	raw_cpu_generic_to_op((pcp), (val), ^=)
 # endif
-# ifndef __this_cpu_xor_4
-#  define __this_cpu_xor_4(pcp, val)	__this_cpu_generic_to_op((pcp), (val), ^=)
+# ifndef raw_cpu_xor_4
+#  define raw_cpu_xor_4(pcp, val)	raw_cpu_generic_to_op((pcp), (val), ^=)
 # endif
-# ifndef __this_cpu_xor_8
-#  define __this_cpu_xor_8(pcp, val)	__this_cpu_generic_to_op((pcp), (val), ^=)
+# ifndef raw_cpu_xor_8
+#  define raw_cpu_xor_8(pcp, val)	raw_cpu_generic_to_op((pcp), (val), ^=)
 # endif
-# define __this_cpu_xor(pcp, val)	__pcpu_size_call(__this_cpu_xor_, (pcp), (val))
+# define raw_cpu_xor(pcp, val)		__pcpu_size_call(raw_cpu_xor_, (pcp), (val))
 #endif
 
-#define __this_cpu_generic_add_return(pcp, val)				\
+#define raw_cpu_generic_add_return(pcp, val)				\
 ({									\
-	__this_cpu_add(pcp, val);					\
-	__this_cpu_read(pcp);						\
+	raw_cpu_add(pcp, val);						\
+	raw_cpu_read(pcp);						\
 })
 
-#ifndef __this_cpu_add_return
-# ifndef __this_cpu_add_return_1
-#  define __this_cpu_add_return_1(pcp, val)	__this_cpu_generic_add_return(pcp, val)
+#ifndef raw_cpu_add_return
+# ifndef raw_cpu_add_return_1
+#  define raw_cpu_add_return_1(pcp, val)	raw_cpu_generic_add_return(pcp, val)
 # endif
-# ifndef __this_cpu_add_return_2
-#  define __this_cpu_add_return_2(pcp, val)	__this_cpu_generic_add_return(pcp, val)
+# ifndef raw_cpu_add_return_2
+#  define raw_cpu_add_return_2(pcp, val)	raw_cpu_generic_add_return(pcp, val)
 # endif
-# ifndef __this_cpu_add_return_4
-#  define __this_cpu_add_return_4(pcp, val)	__this_cpu_generic_add_return(pcp, val)
+# ifndef raw_cpu_add_return_4
+#  define raw_cpu_add_return_4(pcp, val)	raw_cpu_generic_add_return(pcp, val)
 # endif
-# ifndef __this_cpu_add_return_8
-#  define __this_cpu_add_return_8(pcp, val)	__this_cpu_generic_add_return(pcp, val)
+# ifndef raw_cpu_add_return_8
+#  define raw_cpu_add_return_8(pcp, val)	raw_cpu_generic_add_return(pcp, val)
 # endif
-# define __this_cpu_add_return(pcp, val)	\
-	__pcpu_size_call_return2(__this_cpu_add_return_, pcp, val)
+# define raw_cpu_add_return(pcp, val)	\
+	__pcpu_size_call_return2(raw_cpu_add_return_, pcp, val)
 #endif
 
-#define __this_cpu_sub_return(pcp, val)	__this_cpu_add_return(pcp, -(val))
-#define __this_cpu_inc_return(pcp)	__this_cpu_add_return(pcp, 1)
-#define __this_cpu_dec_return(pcp)	__this_cpu_add_return(pcp, -1)
+#define raw_cpu_sub_return(pcp, val)	raw_cpu_add_return(pcp, -(val))
+#define raw_cpu_inc_return(pcp)	raw_cpu_add_return(pcp, 1)
+#define raw_cpu_dec_return(pcp)	raw_cpu_add_return(pcp, -1)
 
-#define __this_cpu_generic_xchg(pcp, nval)				\
+#define raw_cpu_generic_xchg(pcp, nval)					\
 ({	typeof(pcp) ret__;						\
-	ret__ = __this_cpu_read(pcp);					\
-	__this_cpu_write(pcp, nval);					\
+	ret__ = raw_cpu_read(pcp);					\
+	raw_cpu_write(pcp, nval);					\
 	ret__;								\
 })
 
-#ifndef __this_cpu_xchg
-# ifndef __this_cpu_xchg_1
-#  define __this_cpu_xchg_1(pcp, nval)	__this_cpu_generic_xchg(pcp, nval)
+#ifndef raw_cpu_xchg
+# ifndef raw_cpu_xchg_1
+#  define raw_cpu_xchg_1(pcp, nval)	raw_cpu_generic_xchg(pcp, nval)
 # endif
-# ifndef __this_cpu_xchg_2
-#  define __this_cpu_xchg_2(pcp, nval)	__this_cpu_generic_xchg(pcp, nval)
+# ifndef raw_cpu_xchg_2
+#  define raw_cpu_xchg_2(pcp, nval)	raw_cpu_generic_xchg(pcp, nval)
 # endif
-# ifndef __this_cpu_xchg_4
-#  define __this_cpu_xchg_4(pcp, nval)	__this_cpu_generic_xchg(pcp, nval)
+# ifndef raw_cpu_xchg_4
+#  define raw_cpu_xchg_4(pcp, nval)	raw_cpu_generic_xchg(pcp, nval)
 # endif
-# ifndef __this_cpu_xchg_8
-#  define __this_cpu_xchg_8(pcp, nval)	__this_cpu_generic_xchg(pcp, nval)
+# ifndef raw_cpu_xchg_8
+#  define raw_cpu_xchg_8(pcp, nval)	raw_cpu_generic_xchg(pcp, nval)
 # endif
-# define __this_cpu_xchg(pcp, nval)	\
-	__pcpu_size_call_return2(__this_cpu_xchg_, (pcp), nval)
+# define raw_cpu_xchg(pcp, nval)	\
+	__pcpu_size_call_return2(raw_cpu_xchg_, (pcp), nval)
 #endif
 
-#define __this_cpu_generic_cmpxchg(pcp, oval, nval)			\
+#define raw_cpu_generic_cmpxchg(pcp, oval, nval)			\
 ({									\
 	typeof(pcp) ret__;						\
-	ret__ = __this_cpu_read(pcp);					\
+	ret__ = raw_cpu_read(pcp);					\
 	if (ret__ == (oval))						\
-		__this_cpu_write(pcp, nval);				\
+		raw_cpu_write(pcp, nval);				\
 	ret__;								\
 })
 
-#ifndef __this_cpu_cmpxchg
-# ifndef __this_cpu_cmpxchg_1
-#  define __this_cpu_cmpxchg_1(pcp, oval, nval)	__this_cpu_generic_cmpxchg(pcp, oval, nval)
+#ifndef raw_cpu_cmpxchg
+# ifndef raw_cpu_cmpxchg_1
+#  define raw_cpu_cmpxchg_1(pcp, oval, nval)	raw_cpu_generic_cmpxchg(pcp, oval, nval)
 # endif
-# ifndef __this_cpu_cmpxchg_2
-#  define __this_cpu_cmpxchg_2(pcp, oval, nval)	__this_cpu_generic_cmpxchg(pcp, oval, nval)
+# ifndef raw_cpu_cmpxchg_2
+#  define raw_cpu_cmpxchg_2(pcp, oval, nval)	raw_cpu_generic_cmpxchg(pcp, oval, nval)
 # endif
-# ifndef __this_cpu_cmpxchg_4
-#  define __this_cpu_cmpxchg_4(pcp, oval, nval)	__this_cpu_generic_cmpxchg(pcp, oval, nval)
+# ifndef raw_cpu_cmpxchg_4
+#  define raw_cpu_cmpxchg_4(pcp, oval, nval)	raw_cpu_generic_cmpxchg(pcp, oval, nval)
 # endif
-# ifndef __this_cpu_cmpxchg_8
-#  define __this_cpu_cmpxchg_8(pcp, oval, nval)	__this_cpu_generic_cmpxchg(pcp, oval, nval)
+# ifndef raw_cpu_cmpxchg_8
+#  define raw_cpu_cmpxchg_8(pcp, oval, nval)	raw_cpu_generic_cmpxchg(pcp, oval, nval)
 # endif
-# define __this_cpu_cmpxchg(pcp, oval, nval)	\
-	__pcpu_size_call_return2(__this_cpu_cmpxchg_, pcp, oval, nval)
+# define raw_cpu_cmpxchg(pcp, oval, nval)	\
+	__pcpu_size_call_return2(raw_cpu_cmpxchg_, pcp, oval, nval)
 #endif
 
-#define __this_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)	\
+#define raw_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)	\
 ({									\
 	int __ret = 0;							\
-	if (__this_cpu_read(pcp1) == (oval1) &&				\
-			 __this_cpu_read(pcp2)  == (oval2)) {		\
-		__this_cpu_write(pcp1, (nval1));			\
-		__this_cpu_write(pcp2, (nval2));			\
+	if (raw_cpu_read(pcp1) == (oval1) &&				\
+			 raw_cpu_read(pcp2)  == (oval2)) {		\
+		raw_cpu_write(pcp1, (nval1));				\
+		raw_cpu_write(pcp2, (nval2));				\
 		__ret = 1;						\
 	}								\
 	(__ret);							\
 })
 
-#ifndef __this_cpu_cmpxchg_double
-# ifndef __this_cpu_cmpxchg_double_1
-#  define __this_cpu_cmpxchg_double_1(pcp1, pcp2, oval1, oval2, nval1, nval2)	\
-	__this_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)
+#ifndef raw_cpu_cmpxchg_double
+# ifndef raw_cpu_cmpxchg_double_1
+#  define raw_cpu_cmpxchg_double_1(pcp1, pcp2, oval1, oval2, nval1, nval2)	\
+	raw_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)
 # endif
-# ifndef __this_cpu_cmpxchg_double_2
-#  define __this_cpu_cmpxchg_double_2(pcp1, pcp2, oval1, oval2, nval1, nval2)	\
-	__this_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)
+# ifndef raw_cpu_cmpxchg_double_2
+#  define raw_cpu_cmpxchg_double_2(pcp1, pcp2, oval1, oval2, nval1, nval2)	\
+	raw_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)
 # endif
-# ifndef __this_cpu_cmpxchg_double_4
-#  define __this_cpu_cmpxchg_double_4(pcp1, pcp2, oval1, oval2, nval1, nval2)	\
-	__this_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)
+# ifndef raw_cpu_cmpxchg_double_4
+#  define raw_cpu_cmpxchg_double_4(pcp1, pcp2, oval1, oval2, nval1, nval2)	\
+	raw_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)
 # endif
-# ifndef __this_cpu_cmpxchg_double_8
-#  define __this_cpu_cmpxchg_double_8(pcp1, pcp2, oval1, oval2, nval1, nval2)	\
-	__this_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)
+# ifndef raw_cpu_cmpxchg_double_8
+#  define raw_cpu_cmpxchg_double_8(pcp1, pcp2, oval1, oval2, nval1, nval2)	\
+	raw_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)
 # endif
-# define __this_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)	\
-	__pcpu_double_call_return_bool(__this_cpu_cmpxchg_double_, (pcp1), (pcp2), (oval1), (oval2), (nval1), (nval2))
+# define raw_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)	\
+	__pcpu_double_call_return_bool(raw_cpu_cmpxchg_double_, (pcp1), (pcp2), (oval1), (oval2), (nval1), (nval2))
+#endif
+
+#ifdef CONFIG_DEBUG_PREEMPT
+extern void __this_cpu_preempt_check(const char *msg);
+#else
+static inline void __this_cpu_preempt_check(const char *msg) { }
 #endif
 
+/*
+ * Generic percpu operations for context that are safe from preemption/interrupts.
+ * These functions verify that preemption has been disabled.
+ */
+#define __this_cpu_read(pcp)						\
+	(__this_cpu_preempt_check("read"),  raw_cpu_read(pcp))
+
+#define __this_cpu_write(pcp, val)					\
+do { 									\
+	__this_cpu_preempt_check("write");				\
+	raw_cpu_write((pcp), (val));					\
+} while (0)
+
+#define __this_cpu_add(pcp, val)					\
+do {									\
+	__this_cpu_preempt_check("add");				\
+	raw_cpu_add((pcp), (val));					\
+} while (0)
+
+#define __this_cpu_sub(pcp, val)					\
+do {									\
+	__this_cpu_preempt_check("sub");				\
+	raw_cpu_sub((pcp), (val));					\
+} while (0)
+
+#define __this_cpu_inc(pcp)						\
+do {									\
+	__this_cpu_preempt_check("inc");				\
+	raw_cpu_inc(pcp);						\
+} while (0)
+
+#define __this_cpu_dec(pcp)						\
+do {									\
+	__this_cpu_preempt_check("dec");				\
+	raw_cpu_dec(pcp);						\
+} while (0)
+
+#define __this_cpu_and(pcp, val)					\
+do {									\
+	__this_cpu_preempt_check("and");				\
+	raw_cpu_and((pcp), (val));					\
+} while (0)
+
+#define __this_cpu_or(pcp, val)						\
+do {									\
+	__this_cpu_preempt_check("or");					\
+	raw_cpu_or((pcp), (val));					\
+} while (0)
+
+#define __this_cpu_xor(pcp, val)					\
+do {									\
+	__this_cpu_preempt_check("xor");				\
+	raw_cpu_xor((pcp), (val));					\
+} while (0)
+
+#define __this_cpu_add_return(pcp, val)					\
+	(__this_cpu_preempt_check("add_return"), raw_cpu_add_return((pcp), (val)))
+
+#define __this_cpu_sub_return(pcp, val)					\
+	(__this_cpu_preempt_check("sub_return"), raw_cpu_sub_return((pcp), (val)))
+
+#define __this_cpu_inc_return(pcp)					\
+	(__this_cpu_preempt_check("inc_return"), raw_cpu_inc_return(pcp))
+
+#define __this_cpu_dec_return(pcp)					\
+	(__this_cpu_preempt_check("dec_return"), raw_cpu_dec_return(pcp))
+
+#define __this_cpu_xchg(pcp, val)					\
+	(__this_cpu_preempt_check("xchg"),    raw_cpu_xchg((pcp), (val)))
+
+#define __this_cpu_cmpxchg(pcp, oval, nval)				\
+	(__this_cpu_preempt_check("cmpxchg"), raw_cpu_cmpxchg((pcp), (oval), (nval)))
+
+#define __this_cpu_cmpxchg_double(pcp, oval1, oval2, nval1, nval2)	\
+	(__this_cpu_preempt_check("cmpxchg_double"), 			\
+	 raw_cpu_cmpxchg_double((pcp), (oval1), (oval2), (nval1), (nval2)))
+
 #endif /* __LINUX_PERCPU_H */
diff --git a/lib/smp_processor_id.c b/lib/smp_processor_id.c
index 04abe53..f474347 100644
--- a/lib/smp_processor_id.c
+++ b/lib/smp_processor_id.c
@@ -7,7 +7,7 @@
 #include <linux/kallsyms.h>
 #include <linux/sched.h>
 
-notrace unsigned int debug_smp_processor_id(void)
+notrace static unsigned int debug_preempt_check(char *msg)
 {
 	int this_cpu = raw_smp_processor_id();
 
@@ -38,9 +38,8 @@ notrace unsigned int debug_smp_processor_id(void)
 	if (!printk_ratelimit())
 		goto out_enable;
 
-	printk(KERN_ERR "BUG: using smp_processor_id() in preemptible [%08x] "
-			"code: %s/%d\n",
-			preempt_count() - 1, current->comm, current->pid);
+	printk(KERN_ERR "BUG: using %s in preemptible [%08x] code: %s/%d\n",
+			msg, preempt_count() - 1, current->comm, current->pid);
 	print_symbol("caller is %s\n", (long)__builtin_return_address(0));
 	dump_stack();
 
@@ -50,5 +49,17 @@ notrace unsigned int debug_smp_processor_id(void)
 	return this_cpu;
 }
 
+notrace unsigned int debug_smp_processor_id(void)
+{
+	return debug_preempt_check("smp_processor_id()");
+}
 EXPORT_SYMBOL(debug_smp_processor_id);
 
+notrace void __this_cpu_preempt_check(const char *msg)
+{
+	char op[40];
+
+	snprintf(op, sizeof(op), "__this_cpu_%s()", msg);
+	debug_preempt_check(op);
+}
+EXPORT_SYMBOL(__this_cpu_preempt_check);
--
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