linux-kernel - Re: [PATCH] tracing: Partial revert of "tracing: Centralize preemptirq tracepoints and unify their usage"

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Date:   Mon, 6 Aug 2018 22:00:40 -0400
From:   Steven Rostedt <rostedt@...dmis.org>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Joel Fernandes <joel@...lfernandes.org>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH] tracing: Partial revert of "tracing: Centralize
 preemptirq tracepoints and unify their usage"

On Mon, 6 Aug 2018 21:54:32 -0400
Steven Rostedt <rostedt@...dmis.org> wrote:

> --- a/kernel/trace/trace_preemptirq.c
> +++ b/kernel/trace/trace_preemptirq.c
> @@ -20,40 +20,52 @@ static DEFINE_PER_CPU(int, tracing_irq_cpu);
>  void trace_hardirqs_on(void)
>  {
>  	if (!this_cpu_read(tracing_irq_cpu))
> -		return;
> +		goto out;
>  
>  	trace_irq_enable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
>  	this_cpu_write(tracing_irq_cpu, 0);
> +
> + out:
> +	lockdep_hardirqs_on(CALLER_ADDR0);
>  }
>  EXPORT_SYMBOL(trace_hardirqs_on);
>  
>  void trace_hardirqs_off(void)
>  {
>  	if (this_cpu_read(tracing_irq_cpu))
> -		return;
> +		goto out;
>  
>  	this_cpu_write(tracing_irq_cpu, 1);
>  	trace_irq_disable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
> +
> + out:
> +	lockdep_hardirqs_off(CALLER_ADDR0);
>  }
>  EXPORT_SYMBOL(trace_hardirqs_off);
>  
>  __visible void trace_hardirqs_on_caller(unsigned long caller_addr)
>  {
>  	if (!this_cpu_read(tracing_irq_cpu))
> -		return;
> +		goto out;
>  
>  	trace_irq_enable_rcuidle(CALLER_ADDR0, caller_addr);
>  	this_cpu_write(tracing_irq_cpu, 0);
> +
> + out:
> +	lockdep_hardirqs_on(CALLER_ADDR0);
>  }
>  EXPORT_SYMBOL(trace_hardirqs_on_caller);
>  
>  __visible void trace_hardirqs_off_caller(unsigned long caller_addr)
>  {
>  	if (this_cpu_read(tracing_irq_cpu))
> -		return;
> +		goto out;
>  
>  	this_cpu_write(tracing_irq_cpu, 1);
>  	trace_irq_disable_rcuidle(CALLER_ADDR0, caller_addr);
> +
> + out:
> +	lockdep_hardirqs_off(CALLER_ADDR0);
>  }
>  EXPORT_SYMBOL(trace_hardirqs_off_caller);
>  #endif /* CONFIG_TRACE_IRQFLAGS */

Hmm, the gotos above are rather ugly. This look better?

-- Steve


diff --git a/kernel/trace/trace_preemptirq.c b/kernel/trace/trace_preemptirq.c
index e76b78bf258e..fa656b25f427 100644
--- a/kernel/trace/trace_preemptirq.c
+++ b/kernel/trace/trace_preemptirq.c
@@ -19,41 +19,45 @@ static DEFINE_PER_CPU(int, tracing_irq_cpu);
 
 void trace_hardirqs_on(void)
 {
-	if (!this_cpu_read(tracing_irq_cpu))
-		return;
+	if (this_cpu_read(tracing_irq_cpu)) {
+		trace_irq_enable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
+		this_cpu_write(tracing_irq_cpu, 0);
+	}
 
-	trace_irq_enable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
-	this_cpu_write(tracing_irq_cpu, 0);
+	lockdep_hardirqs_on(CALLER_ADDR0);
 }
 EXPORT_SYMBOL(trace_hardirqs_on);
 
 void trace_hardirqs_off(void)
 {
-	if (this_cpu_read(tracing_irq_cpu))
-		return;
+	if (!this_cpu_read(tracing_irq_cpu)) {
+		this_cpu_write(tracing_irq_cpu, 1);
+		trace_irq_disable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
+	}
 
-	this_cpu_write(tracing_irq_cpu, 1);
-	trace_irq_disable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
+	lockdep_hardirqs_off(CALLER_ADDR0);
 }
 EXPORT_SYMBOL(trace_hardirqs_off);
 
 __visible void trace_hardirqs_on_caller(unsigned long caller_addr)
 {
-	if (!this_cpu_read(tracing_irq_cpu))
-		return;
+	if (this_cpu_read(tracing_irq_cpu)) {
+		trace_irq_enable_rcuidle(CALLER_ADDR0, caller_addr);
+		this_cpu_write(tracing_irq_cpu, 0);
+	}
 
-	trace_irq_enable_rcuidle(CALLER_ADDR0, caller_addr);
-	this_cpu_write(tracing_irq_cpu, 0);
+	lockdep_hardirqs_on(CALLER_ADDR0);
 }
 EXPORT_SYMBOL(trace_hardirqs_on_caller);
 
 __visible void trace_hardirqs_off_caller(unsigned long caller_addr)
 {
-	if (this_cpu_read(tracing_irq_cpu))
-		return;
+	if (!this_cpu_read(tracing_irq_cpu)) {
+		this_cpu_write(tracing_irq_cpu, 1);
+		trace_irq_disable_rcuidle(CALLER_ADDR0, caller_addr);
+	}
 
-	this_cpu_write(tracing_irq_cpu, 1);
-	trace_irq_disable_rcuidle(CALLER_ADDR0, caller_addr);
+	lockdep_hardirqs_off(CALLER_ADDR0);
 }
 EXPORT_SYMBOL(trace_hardirqs_off_caller);
 #endif /* CONFIG_TRACE_IRQFLAGS */