[tip: x86/entry] genirq: Provide __irq_enter/exit_raw()

[tip-bot2 for Thomas Gleixner]

The following commit has been merged into the x86/entry branch of tip:

Commit-ID:     355e1262d6038b37f0dbf5f3cfe64cc85d471b7b
Gitweb:        https://git.kernel.org/tip/355e1262d6038b37f0dbf5f3cfe64cc85d471b7b
Author:        Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate:    Thu, 21 May 2020 22:05:22 +02:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Tue, 26 May 2020 19:06:27 +02:00

genirq: Provide __irq_enter/exit_raw()

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>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Reviewed-by: Andy Lutomirski <luto@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20200521202117.671682341@xxxxxxxxxxxxx
---
 include/linux/hardirq.h | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h
index 3dc9102..03c9fec 100644
--- a/include/linux/hardirq.h
+++ b/include/linux/hardirq.h
@@ -38,6 +38,17 @@ static __always_inline void rcu_irq_enter_check_tick(void)
 	} 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);
@@ -57,6 +68,15 @@ void irq_enter_rcu(void);
 	} 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:
  */
 void irq_exit(void);