3 files changed, 84 insertions, 6 deletions

diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 4515232..ab58c33 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -58,6 +58,7 @@ struct trace_entry {
 	int			pid;
 	unsigned short		migrate_disable;
 	unsigned short		padding;
+	unsigned char		preempt_lazy_count;
 };
 
 #define FTRACE_MAX_EVENT						\
diff --git a/include/linux/preempt.h b/include/linux/preempt.h
index 7d08aab..c153cf2 100644
--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -23,15 +23,38 @@
 
 #define preempt_count()	(current_thread_info()->preempt_count)
 
+#ifdef CONFIG_PREEMPT_LAZY
+#define add_preempt_lazy_count(val)	do { preempt_lazy_count() += (val); } while (0)
+#define sub_preempt_lazy_count(val)	do { preempt_lazy_count() -= (val); } while (0)
+#define inc_preempt_lazy_count()	add_preempt_lazy_count(1)
+#define dec_preempt_lazy_count()	sub_preempt_lazy_count(1)
+#define preempt_lazy_count()		(current_thread_info()->preempt_lazy_count)
+#else
+#define add_preempt_lazy_count(val)	do { } while (0)
+#define sub_preempt_lazy_count(val)	do { } while (0)
+#define inc_preempt_lazy_count()	do { } while (0)
+#define dec_preempt_lazy_count()	do { } while (0)
+#define preempt_lazy_count()		(0)
+#endif
+
 #ifdef CONFIG_PREEMPT
 
 asmlinkage void preempt_schedule(void);
 
+# ifdef CONFIG_PREEMPT_LAZY
 #define preempt_check_resched() \
 do { \
-	if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) \
+	if (unlikely(test_thread_flag(TIF_NEED_RESCHED) || \
+		     test_thread_flag(TIF_NEED_RESCHED_LAZY)))  \
 		preempt_schedule(); \
 } while (0)
+# else
+#define preempt_check_resched() \
+do { \
+	if (unlikely(test_thread_flag(TIF_NEED_RESCHED)))	\
+		preempt_schedule(); \
+} while (0)
+# endif
 
 #ifdef CONFIG_CONTEXT_TRACKING
 
@@ -64,6 +87,12 @@ do { \
 	barrier(); \
 } while (0)
 
+#define preempt_lazy_disable() \
+do { \
+	inc_preempt_lazy_count(); \
+	barrier(); \
+} while (0)
+
 #define sched_preempt_enable_no_resched() \
 do { \
 	barrier(); \
@@ -85,6 +114,13 @@ do { \
 	preempt_check_resched(); \
 } while (0)
 
+#define preempt_lazy_enable() \
+do { \
+	dec_preempt_lazy_count(); \
+	barrier(); \
+	preempt_check_resched(); \
+} while (0)
+
 /* For debugging and tracer internals only! */
 #define add_preempt_count_notrace(val)			\
 	do { preempt_count() += (val); } while (0)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 88815fc..3ce814c 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2490,6 +2490,52 @@ static inline int test_tsk_need_resched(struct task_struct *tsk)
 	return unlikely(test_tsk_thread_flag(tsk,TIF_NEED_RESCHED));
 }
 
+#ifdef CONFIG_PREEMPT_LAZY
+static inline void set_tsk_need_resched_lazy(struct task_struct *tsk)
+{
+	set_tsk_thread_flag(tsk,TIF_NEED_RESCHED_LAZY);
+}
+
+static inline void clear_tsk_need_resched_lazy(struct task_struct *tsk)
+{
+	clear_tsk_thread_flag(tsk,TIF_NEED_RESCHED_LAZY);
+}
+
+static inline int test_tsk_need_resched_lazy(struct task_struct *tsk)
+{
+	return unlikely(test_tsk_thread_flag(tsk,TIF_NEED_RESCHED_LAZY));
+}
+
+static inline int need_resched_lazy(void)
+{
+	return test_thread_flag(TIF_NEED_RESCHED_LAZY);
+}
+
+static inline int need_resched_now(void)
+{
+	return test_thread_flag(TIF_NEED_RESCHED);
+}
+
+static inline int need_resched(void)
+{
+	return test_thread_flag(TIF_NEED_RESCHED) ||
+		test_thread_flag(TIF_NEED_RESCHED_LAZY);
+}
+#else
+static inline void clear_tsk_need_resched_lazy(struct task_struct *tsk) { }
+static inline int need_resched_lazy(void) { return 0; }
+
+static inline int need_resched_now(void)
+{
+	return test_thread_flag(TIF_NEED_RESCHED);
+}
+
+static inline int need_resched(void)
+{
+	return test_thread_flag(TIF_NEED_RESCHED);
+}
+#endif
+
 static inline int restart_syscall(void)
 {
 	set_tsk_thread_flag(current, TIF_SIGPENDING);
@@ -2521,11 +2567,6 @@ static inline int signal_pending_state(long state, struct task_struct *p)
 	return (state & TASK_INTERRUPTIBLE) || __fatal_signal_pending(p);
 }
 
-static inline int need_resched(void)
-{
-	return unlikely(test_thread_flag(TIF_NEED_RESCHED));
-}
-
 static inline bool __task_is_stopped_or_traced(struct task_struct *task)
 {
 	if (task->state & (__TASK_STOPPED | __TASK_TRACED))