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Subject[PATCH] softirq,tracing: enable to trace softirq raise latency

Add a tracepoint for tracing when softirq action is raised.

It and the existed tracepoints complete softirq's tracepoints:
softirq_raise, softirq_entry and softirq_exit.

And when this tracepoint is used in combination with
the softirq_entry tracepoint we can determine
the softirq raise latency.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
---
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 75f3f00..b368d5d 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -18,6 +18,7 @@
#include <asm/atomic.h>
#include <asm/ptrace.h>
#include <asm/system.h>
+#include <trace/events/irq.h>

/*
* These correspond to the IORESOURCE_IRQ_* defines in
@@ -372,7 +373,13 @@ asmlinkage void do_softirq(void);
asmlinkage void __do_softirq(void);
extern void open_softirq(int nr, void (*action)(struct softirq_action *));
extern void softirq_init(void);
-#define __raise_softirq_irqoff(nr) do { or_softirq_pending(1UL << (nr)); } while (0)
+
+static inline void __raise_softirq_irqoff(unsigned int nr)
+{
+ trace_softirq_raise(nr);
+ or_softirq_pending(1UL << nr);
+}
+
extern void raise_softirq_irqoff(unsigned int nr);
extern void raise_softirq(unsigned int nr);
extern void wakeup_softirqd(void);
diff --git a/include/trace/events/irq.h b/include/trace/events/irq.h
index dcfcd44..799af09 100644
--- a/include/trace/events/irq.h
+++ b/include/trace/events/irq.h
@@ -5,7 +5,9 @@
#define _TRACE_IRQ_H

#include <linux/tracepoint.h>
-#include <linux/interrupt.h>
+
+struct irqaction;
+struct softirq_action;

#define softirq_name(sirq) { sirq##_SOFTIRQ, #sirq }
#define show_softirq_name(val) \
@@ -83,6 +85,32 @@ TRACE_EVENT(irq_handler_exit,
);

/**
+ * softirq_raise - called immediately when a softirq is raised
+ * @nr: softirq vector number
+ *
+ * Tracepoint for tracing when softirq action is raised.
+ * Also, when used in combination with the softirq_entry tracepoint
+ * we can determine the softirq raise latency.
+ */
+TRACE_EVENT(softirq_raise,
+
+ TP_PROTO(unsigned int nr),
+
+ TP_ARGS(nr),
+
+ TP_STRUCT__entry(
+ __field( unsigned int, vec )
+ ),
+
+ TP_fast_assign(
+ __entry->vec = nr;
+ ),
+
+ TP_printk("vec=%d [action=%s]", __entry->vec,
+ show_softirq_name(__entry->vec))
+);
+
+/**
* softirq_entry - called immediately before the softirq handler
* @h: pointer to struct softirq_action
* @vec: pointer to first struct softirq_action in softirq_vec array
@@ -100,11 +128,11 @@ TRACE_EVENT(softirq_entry,
TP_ARGS(h, vec),

TP_STRUCT__entry(
- __field( int, vec )
+ __field( unsigned int, vec )
),

TP_fast_assign(
- __entry->vec = (int)(h - vec);
+ __entry->vec = (unsigned int)(h - vec);
),

TP_printk("vec=%d [action=%s]", __entry->vec,
@@ -129,11 +157,11 @@ TRACE_EVENT(softirq_exit,
TP_ARGS(h, vec),

TP_STRUCT__entry(
- __field( int, vec )
+ __field( unsigned int, vec )
),

TP_fast_assign(
- __entry->vec = (int)(h - vec);
+ __entry->vec = (unsigned int)(h - vec);
),

TP_printk("vec=%d [action=%s]", __entry->vec,


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