[2/4] ARM: add IPI tracepoints

Message ID 1405660735-13408-3-git-send-email-nicolas.pitre@linaro.org
State New
Headers show

Commit Message

Nicolas Pitre July 18, 2014, 5:18 a.m.
The strings used to list IPIs in /proc/interrupts are reused for tracing
purposes.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
---
 arch/arm/kernel/smp.c | 72 ++++++++++++++++++++++++++++++++-------------------
 1 file changed, 45 insertions(+), 27 deletions(-)

Comments

Steven Rostedt July 18, 2014, 8:04 p.m. | #1
On Fri, 18 Jul 2014 01:18:53 -0400
Nicolas Pitre <nicolas.pitre@linaro.org> wrote:

  
> -#ifdef CONFIG_IRQ_WORK
> -void arch_irq_work_raise(void)
> -{
> -	if (is_smp())
> -		smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK);
> -}
> +static const char *ipi_types[NR_IPI]
> +#ifdef CONFIG_TRACING
> +__tracepoint_string
>  #endif

Oh, this is ugly. I should probably add a define when !CONFIG_TRACING
is set. Something like:

#ifdef CONFIG_TRACING
...
#else
# define __tracepoint_string
#endif

Such that users of __tracepoint_string don't need to add ugly ifdefs in
the code.

If you want to add that to ftrace_event.h to this series, I'll ack it.

-- Steve


> -
> -static const char *ipi_types[NR_IPI] = {
> += {
>  #define S(x,s)	[x] = s
>  	S(IPI_WAKEUP, "CPU wakeup interrupts"),
>  	S(IPI_TIMER, "Timer broadcast interrupts"),
> @@ -473,6 +457,12 @@ static const char *ipi_types[NR_IPI] = {
>  	S(IPI_COMPLETION, "completion interrupts"),
>  };
>  
--
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Patch

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 7c4fada440..daedff319b 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -47,6 +47,9 @@ 
 #include <asm/mach/arch.h>
 #include <asm/mpu.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/ipi.h>
+
 /*
  * as from 2.5, kernels no longer have an init_tasks structure
  * so we need some other way of telling a new secondary core
@@ -430,38 +433,19 @@  void __init smp_prepare_cpus(unsigned int max_cpus)
 	}
 }
 
-static void (*smp_cross_call)(const struct cpumask *, unsigned int);
+static void (*__smp_cross_call)(const struct cpumask *, unsigned int);
 
 void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
 {
-	if (!smp_cross_call)
-		smp_cross_call = fn;
-}
-
-void arch_send_call_function_ipi_mask(const struct cpumask *mask)
-{
-	smp_cross_call(mask, IPI_CALL_FUNC);
-}
-
-void arch_send_wakeup_ipi_mask(const struct cpumask *mask)
-{
-	smp_cross_call(mask, IPI_WAKEUP);
-}
-
-void arch_send_call_function_single_ipi(int cpu)
-{
-	smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
+	if (!__smp_cross_call)
+		__smp_cross_call = fn;
 }
 
-#ifdef CONFIG_IRQ_WORK
-void arch_irq_work_raise(void)
-{
-	if (is_smp())
-		smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK);
-}
+static const char *ipi_types[NR_IPI]
+#ifdef CONFIG_TRACING
+__tracepoint_string
 #endif
-
-static const char *ipi_types[NR_IPI] = {
+= {
 #define S(x,s)	[x] = s
 	S(IPI_WAKEUP, "CPU wakeup interrupts"),
 	S(IPI_TIMER, "Timer broadcast interrupts"),
@@ -473,6 +457,12 @@  static const char *ipi_types[NR_IPI] = {
 	S(IPI_COMPLETION, "completion interrupts"),
 };
 
+static void smp_cross_call(const struct cpumask *target, unsigned int ipinr)
+{
+	trace_ipi_raise(target, ipi_types[ipinr]);
+	__smp_cross_call(target, ipinr);
+}
+
 void show_ipi_list(struct seq_file *p, int prec)
 {
 	unsigned int cpu, i;
@@ -499,6 +489,29 @@  u64 smp_irq_stat_cpu(unsigned int cpu)
 	return sum;
 }
 
+void arch_send_call_function_ipi_mask(const struct cpumask *mask)
+{
+	smp_cross_call(mask, IPI_CALL_FUNC);
+}
+
+void arch_send_wakeup_ipi_mask(const struct cpumask *mask)
+{
+	smp_cross_call(mask, IPI_WAKEUP);
+}
+
+void arch_send_call_function_single_ipi(int cpu)
+{
+	smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
+}
+
+#ifdef CONFIG_IRQ_WORK
+void arch_irq_work_raise(void)
+{
+	if (is_smp())
+		smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK);
+}
+#endif
+
 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
 void tick_broadcast(const struct cpumask *mask)
 {
@@ -556,8 +569,10 @@  void handle_IPI(int ipinr, struct pt_regs *regs)
 	unsigned int cpu = smp_processor_id();
 	struct pt_regs *old_regs = set_irq_regs(regs);
 
-	if (ipinr < NR_IPI)
+	if ((unsigned)ipinr < NR_IPI) {
+		trace_ipi_entry(ipi_types[ipinr]);
 		__inc_irq_stat(cpu, ipi_irqs[ipinr]);
+	}
 
 	switch (ipinr) {
 	case IPI_WAKEUP:
@@ -612,6 +627,9 @@  void handle_IPI(int ipinr, struct pt_regs *regs)
 		       cpu, ipinr);
 		break;
 	}
+
+	if ((unsigned)ipinr < NR_IPI)
+		trace_ipi_exit(ipi_types[ipinr]);
 	set_irq_regs(old_regs);
 }