* preempt_count (used for kernel preemption, interrupt count, etc.)
*/
-#include <linux/thread_info.h>
#include <linux/linkage.h>
#include <linux/list.h>
*/
#define PREEMPT_NEED_RESCHED 0x80000000
-/*
- * We mask the PREEMPT_NEED_RESCHED bit so as not to confuse all current users
- * that think a non-zero value indicates we cannot preempt.
- */
-static __always_inline int preempt_count(void)
-{
- return current_thread_info()->preempt_count & ~PREEMPT_NEED_RESCHED;
-}
-
-static __always_inline int *preempt_count_ptr(void)
-{
- return ¤t_thread_info()->preempt_count;
-}
-
-/*
- * We now loose PREEMPT_NEED_RESCHED and cause an extra reschedule; however the
- * alternative is loosing a reschedule. Better schedule too often -- also this
- * should be a very rare operation.
- */
-static __always_inline void preempt_count_set(int pc)
-{
- *preempt_count_ptr() = pc;
-}
-
-/*
- * We fold the NEED_RESCHED bit into the preempt count such that
- * preempt_enable() can decrement and test for needing to reschedule with a
- * single instruction.
- *
- * We invert the actual bit, so that when the decrement hits 0 we know we both
- * need to resched (the bit is cleared) and can resched (no preempt count).
- */
-
-static __always_inline void set_preempt_need_resched(void)
-{
- *preempt_count_ptr() &= ~PREEMPT_NEED_RESCHED;
-}
-
-static __always_inline void clear_preempt_need_resched(void)
-{
- *preempt_count_ptr() |= PREEMPT_NEED_RESCHED;
-}
-
-static __always_inline bool test_preempt_need_resched(void)
-{
- return !(*preempt_count_ptr() & PREEMPT_NEED_RESCHED);
-}
+#include <asm/preempt.h>
#if defined(CONFIG_DEBUG_PREEMPT) || defined(CONFIG_PREEMPT_TRACER)
- extern void add_preempt_count(int val);
- extern void sub_preempt_count(int val);
+extern void preempt_count_add(int val);
+extern void preempt_count_sub(int val);
+#define preempt_count_dec_and_test() ({ preempt_count_sub(1); should_resched(); })
#else
-# define add_preempt_count(val) do { *preempt_count_ptr() += (val); } while (0)
-# define sub_preempt_count(val) do { *preempt_count_ptr() -= (val); } while (0)
+#define preempt_count_add(val) __preempt_count_add(val)
+#define preempt_count_sub(val) __preempt_count_sub(val)
+#define preempt_count_dec_and_test() __preempt_count_dec_and_test()
#endif
-#define inc_preempt_count() add_preempt_count(1)
-#define dec_preempt_count() sub_preempt_count(1)
-
-#ifdef CONFIG_PREEMPT
-
-asmlinkage void preempt_schedule(void);
-
-#define preempt_check_resched() \
-do { \
- if (unlikely(!*preempt_count_ptr())) \
- preempt_schedule(); \
-} while (0)
-
-#ifdef CONFIG_CONTEXT_TRACKING
-
-void preempt_schedule_context(void);
-
-#define preempt_check_resched_context() \
-do { \
- if (unlikely(!*preempt_count_ptr())) \
- preempt_schedule_context(); \
-} while (0)
-#else
-
-#define preempt_check_resched_context() preempt_check_resched()
-
-#endif /* CONFIG_CONTEXT_TRACKING */
-
-#else /* !CONFIG_PREEMPT */
-
-#define preempt_check_resched() do { } while (0)
-#define preempt_check_resched_context() do { } while (0)
-
-#endif /* CONFIG_PREEMPT */
+#define __preempt_count_inc() __preempt_count_add(1)
+#define __preempt_count_dec() __preempt_count_sub(1)
+#define preempt_count_inc() preempt_count_add(1)
+#define preempt_count_dec() preempt_count_sub(1)
#ifdef CONFIG_PREEMPT_COUNT
#define preempt_disable() \
do { \
- inc_preempt_count(); \
+ preempt_count_inc(); \
barrier(); \
} while (0)
#define sched_preempt_enable_no_resched() \
do { \
barrier(); \
- dec_preempt_count(); \
+ preempt_count_dec(); \
} while (0)
-#define preempt_enable_no_resched() sched_preempt_enable_no_resched()
+#define preempt_enable_no_resched() sched_preempt_enable_no_resched()
+#ifdef CONFIG_PREEMPT
#define preempt_enable() \
do { \
- preempt_enable_no_resched(); \
- preempt_check_resched(); \
+ barrier(); \
+ if (unlikely(preempt_count_dec_and_test())) \
+ __preempt_schedule(); \
} while (0)
-/* For debugging and tracer internals only! */
-#define add_preempt_count_notrace(val) \
- do { *preempt_count_ptr() += (val); } while (0)
-#define sub_preempt_count_notrace(val) \
- do { *preempt_count_ptr() -= (val); } while (0)
-#define inc_preempt_count_notrace() add_preempt_count_notrace(1)
-#define dec_preempt_count_notrace() sub_preempt_count_notrace(1)
+#define preempt_check_resched() \
+do { \
+ if (should_resched()) \
+ __preempt_schedule(); \
+} while (0)
+
+#else
+#define preempt_enable() preempt_enable_no_resched()
+#define preempt_check_resched() do { } while (0)
+#endif
#define preempt_disable_notrace() \
do { \
- inc_preempt_count_notrace(); \
+ __preempt_count_inc(); \
barrier(); \
} while (0)
#define preempt_enable_no_resched_notrace() \
do { \
barrier(); \
- dec_preempt_count_notrace(); \
+ __preempt_count_dec(); \
} while (0)
-/* preempt_check_resched is OK to trace */
+#ifdef CONFIG_PREEMPT
+
+#ifndef CONFIG_CONTEXT_TRACKING
+#define __preempt_schedule_context() __preempt_schedule()
+#endif
+
#define preempt_enable_notrace() \
do { \
- preempt_enable_no_resched_notrace(); \
- preempt_check_resched_context(); \
+ barrier(); \
+ if (unlikely(__preempt_count_dec_and_test())) \
+ __preempt_schedule_context(); \
} while (0)
+#else
+#define preempt_enable_notrace() preempt_enable_no_resched_notrace()
+#endif
#else /* !CONFIG_PREEMPT_COUNT */
* that can cause faults and scheduling migrate into our preempt-protected
* region.
*/
-#define preempt_disable() barrier()
+#define preempt_disable() barrier()
#define sched_preempt_enable_no_resched() barrier()
-#define preempt_enable_no_resched() barrier()
-#define preempt_enable() barrier()
+#define preempt_enable_no_resched() barrier()
+#define preempt_enable() barrier()
+#define preempt_check_resched() do { } while (0)
#define preempt_disable_notrace() barrier()
#define preempt_enable_no_resched_notrace() barrier()
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