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Commit 39842323 authored by Jason Baron's avatar Jason Baron Committed by Steven Rostedt
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tracing: tracepoints for softirq entry/exit - tracepoints 



Introduce softirq entry/exit tracepoints. These are useful for
augmenting existing tracers, and to figure out softirq frequencies and
timings.

[
  s/irq_softirq_/softirq_/ for trace point names and
  Fixed printf format in TRACE_FORMAT macro
   - Steven Rostedt
]

LKML-Reference: <20090312183603.GC3352@redhat.com>
Signed-off-by: default avatarJason Baron <jbaron@redhat.com>
Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
parent 5d592b44

include/trace/irq_event_types.h

+12 −0
Original line number Diff line number Diff line
@@ -40,4 +40,16 @@ TRACE_EVENT(irq_handler_exit, 
		  __entry->irq, __entry->ret ? "handled" : "unhandled")

);



TRACE_FORMAT(softirq_entry,

	TP_PROTO(struct softirq_action *h, struct softirq_action *vec),

	TP_ARGS(h, vec),

	TP_FMT("softirq=%d action=%s", (int)(h - vec), softirq_to_name[h-vec])

	);



TRACE_FORMAT(softirq_exit,

	TP_PROTO(struct softirq_action *h, struct softirq_action *vec),

	TP_ARGS(h, vec),

	TP_FMT("softirq=%d action=%s", (int)(h - vec), softirq_to_name[h-vec])

	);



#undef TRACE_SYSTEM

kernel/softirq.c

+6 −1
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 
#include <linux/ftrace.h>

#include <linux/smp.h>

#include <linux/tick.h>

#include <trace/irq.h>



#include <asm/irq.h>

/*
@@ -186,6 +187,9 @@ EXPORT_SYMBOL(local_bh_enable_ip); 
 */

#define MAX_SOFTIRQ_RESTART 10



DEFINE_TRACE(softirq_entry);

DEFINE_TRACE(softirq_exit);



asmlinkage void __do_softirq(void)

{

	struct softirq_action *h;
@@ -212,8 +216,9 @@ asmlinkage void __do_softirq(void) 
		if (pending & 1) {

			int prev_count = preempt_count();



			trace_softirq_entry(h, softirq_vec);

			h->action(h);



			trace_softirq_exit(h, softirq_vec);

			if (unlikely(prev_count != preempt_count())) {

				printk(KERN_ERR "huh, entered softirq %td %s %p"

				       "with preempt_count %08x,"