[PATCH v4] ftrace: add a tracepoint for __raise_softirq_irqoff()

Xiao Guangrong
2009-05-14T10:52:59Z

From: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>

This patch is modified from Mathieu Desnoyers' patch. The original patch
can be found here:
http://marc.info/?l=linux-kernel&m=123791201816245&w=2
This tracepoint can trace the time stamp when softirq action is raised.

Changelog for v1 -> v2:
1: Use TRACE_EVENT instead of DEFINE_TRACE
2: Move the tracepoint from raise_softirq_irqoff() to
__raise_softirq_irqoff()

Changelog for v2 -> v3:
Move the definition of __raise_softifq_irqoff() to .c file when
CONFIG_TRACEPOINTS is enabled, to avoid recursive includes

Changelog for v3 -> v4:
1: Come back to v2, and use forward declarations to avoid
recursive includes as Mathieu's suggestion
2: Modifiy the tracepoint name
3: Add comments for this tracepoint

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Review-by: Lai Jiangshan <laijs@cn.fujitsu.com>
---
include/linux/interrupt.h | 9 ++++++++-
include/trace/events/irq.h | 27 ++++++++++++++++++++++++++-
2 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index dd574d5..51e7909 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
@@ -361,7 +362,13 @@ 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 32a9f7e..08fa63b 100644
--- a/include/trace/events/irq.h
+++ b/include/trace/events/irq.h
@@ -2,11 +2,13 @@
#define _TRACE_IRQ_H

#include <linux/tracepoint.h>
-#include <linux/interrupt.h>

#undef TRACE_SYSTEM
#define TRACE_SYSTEM irq

+struct irqaction;
+struct softirq_action;
+
/**
* irq_handler_entry - called immediately before the irq action handler
* @irq: irq number
@@ -128,6 +130,29 @@ TRACE_EVENT(softirq_exit,
TP_printk("softirq=%d action=%s", __entry->vec, __get_str(name))
);

+/**
+ * softirq_raise - called immediately when a softirq is raised
+ * @nr: softirq vector number
+ */
+TRACE_EVENT(softirq_raise,
+
+ TP_PROTO(unsigned int nr),
+
+ TP_ARGS(nr),
+
+ TP_STRUCT__entry(
+ __field( unsigned int, nr )
+ __string( name, softirq_to_name[nr] )
+ ),
+
+ TP_fast_assign(
+ __entry->nr = nr;
+ __assign_str(name, softirq_to_name[nr]);
+ ),
+
+ TP_printk("softirq=%u action=%s", __entry->nr, __get_str(name))
+);
+
#endif /* _TRACE_IRQ_H */

/* This part must be outside protection */
--
1.6.1.2