[PATCH v2 4/5] ARM64: add IPI tracepoints

[Nicolas Pitre]

On Wed, 6 Aug 2014, Steven Rostedt wrote:

> Will and Russell,
> 
> Can you give me your Acked-by for this, and I can pull it through my
> tree?

Catalin (the ARM64 maintainer) already provided his.


> 
> Thanks,
> 
> -- Steve
> 
> 
> On Fri, 25 Jul 2014 16:05:32 -0400
> Nicolas Pitre <nicolas.pitre at linaro.org> wrote:
> 
> > The strings used to list IPIs in /proc/interrupts are reused for tracing
> > purposes.
> > 
> > While at it, the code is slightly cleaned up so the ipi_types array
> > indices are no longer offset by IPI_RESCHEDULE whose value is 0 anyway.
> > 
> > Signed-off-by: Nicolas Pitre <nico at linaro.org>
> > Acked-by: Steven Rostedt <rostedt at goodmis.org>
> > Acked-by: Catalin Marinas <catalin.marinas at arm.com>
> > ---
> >  arch/arm64/kernel/smp.c | 65 +++++++++++++++++++++++++++++--------------------
> >  1 file changed, 39 insertions(+), 26 deletions(-)
> > 
> > diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
> > index 40f38f46c8..a89c66f3b4 100644
> > --- a/arch/arm64/kernel/smp.c
> > +++ b/arch/arm64/kernel/smp.c
> > @@ -50,6 +50,9 @@
> >  #include <asm/tlbflush.h>
> >  #include <asm/ptrace.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
> > @@ -307,8 +310,6 @@ void __init smp_prepare_boot_cpu(void)
> >  	set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
> >  }
> >  
> > -static void (*smp_cross_call)(const struct cpumask *, unsigned int);
> > -
> >  /*
> >   * Enumerate the possible CPU set from the device tree and build the
> >   * cpu logical map array containing MPIDR values related to logical
> > @@ -463,32 +464,15 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
> >  	}
> >  }
> >  
> > +static void (*__smp_cross_call)(const struct cpumask *, unsigned int);
> >  
> >  void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
> >  {
> > -	smp_cross_call = fn;
> > +	__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_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 (smp_cross_call)
> > -		smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK);
> > -}
> > -#endif
> > -
> > -static const char *ipi_types[NR_IPI] = {
> > -#define S(x,s)	[x - IPI_RESCHEDULE] = s
> > +static const char *ipi_types[NR_IPI] __tracepoint_string = {
> > +#define S(x,s)	[x] = s
> >  	S(IPI_RESCHEDULE, "Rescheduling interrupts"),
> >  	S(IPI_CALL_FUNC, "Function call interrupts"),
> >  	S(IPI_CALL_FUNC_SINGLE, "Single function call interrupts"),
> > @@ -497,12 +481,18 @@ static const char *ipi_types[NR_IPI] = {
> >  	S(IPI_IRQ_WORK, "IRQ work 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;
> >  
> >  	for (i = 0; i < NR_IPI; i++) {
> > -		seq_printf(p, "%*s%u:%s", prec - 1, "IPI", i + IPI_RESCHEDULE,
> > +		seq_printf(p, "%*s%u:%s", prec - 1, "IPI", i,
> >  			   prec >= 4 ? " " : "");
> >  		for_each_online_cpu(cpu)
> >  			seq_printf(p, "%10u ",
> > @@ -522,6 +512,24 @@ 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_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 (__smp_cross_call)
> > +		smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK);
> > +}
> > +#endif
> > +
> >  static DEFINE_RAW_SPINLOCK(stop_lock);
> >  
> >  /*
> > @@ -553,8 +561,10 @@ 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 >= IPI_RESCHEDULE && ipinr < IPI_RESCHEDULE + NR_IPI)
> > -		__inc_irq_stat(cpu, ipi_irqs[ipinr - IPI_RESCHEDULE]);
> > +	if ((unsigned)ipinr < NR_IPI) {
> > +		trace_ipi_entry(ipi_types[ipinr]);
> > +		__inc_irq_stat(cpu, ipi_irqs[ipinr]);
> > +	}
> >  
> >  	switch (ipinr) {
> >  	case IPI_RESCHEDULE:
> > @@ -599,6 +609,9 @@ void handle_IPI(int ipinr, struct pt_regs *regs)
> >  		pr_crit("CPU%u: Unknown IPI message 0x%x\n", cpu, ipinr);
> >  		break;
> >  	}
> > +
> > +	if ((unsigned)ipinr < NR_IPI)
> > +		trace_ipi_exit(ipi_types[ipinr]);
> >  	set_irq_regs(old_regs);
> >  }
> >  
> 
>