[patch V9 09/39] genirq: Provide __irq_enter/exit_raw()

[Thomas Gleixner]

From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

Like __irq_enter/exit() but without time accounting. To be used for "empty"
system vectors like the scheduler IPI to avoid the overhead.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Andy Lutomirski <luto@xxxxxxxxxx>
---
 include/linux/hardirq.h |   20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

--- a/include/linux/hardirq.h
+++ b/include/linux/hardirq.h
@@ -50,6 +50,17 @@ static __always_inline void rcu_irq_ente
 	} while (0)
 
 /*
+ * Like __irq_enter() without time accounting for fast
+ * interrupts, e.g. reschedule IPI where time accounting
+ * is more expensive than the actual interrupt.
+ */
+#define __irq_enter_raw()				\
+	do {						\
+		preempt_count_add(HARDIRQ_OFFSET);	\
+		lockdep_hardirq_enter();		\
+	} while (0)
+
+/*
  * Enter irq context (on NO_HZ, update jiffies):
  */
 void irq_enter(void);
@@ -68,6 +79,15 @@ void irq_enter_rcu(void);
 		preempt_count_sub(HARDIRQ_OFFSET);	\
 	} while (0)
 
+/*
+ * Like __irq_exit() without time accounting
+ */
+#define __irq_exit_raw()				\
+	do {						\
+		lockdep_hardirq_exit();			\
+		preempt_count_sub(HARDIRQ_OFFSET);	\
+	} while (0)
+
 /*
  * Exit irq context and process softirqs if needed:
  */