Messages in this thread Patch in this message | | | From | Patrick Bellasi <> | Subject | [PATCH] tracing: Fix trace_preempt_{on,off} for !CONFIG_DEBUG_PREEMPT builds | Date | Mon, 4 Dec 2017 09:46:42 +0000 |
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The new preempt enable/disable events introduced by:
d59158162 tracing: Add support for preempt and irq enable/disable events
are defined only for CONFIG_DEBUG_PREEMPT kernels when the CONFIG_PREEMPTIRQ_EVENTS support, introduced by the above patch, is enabled.
These events are generated within by trace_preempt_{on,off} calls, which are part of the the "Preemption-off Latency Tracer" (CONFIG_PREEMPT_TRACER).
Currently these calls are (correctly) generated on CONFIG_PREEMPT_TRACER even when the kernel is !CONFIG_DEBUG_PREEMPT configured. Thus leading to an undefined reference to the new trace events.
Let's ensure that we always have an (eventually) empty definition of the events for CONFIG_PREEMPTIRQ_EVENTS kernels.
This patch will ensure that the additional preempt enabled/disable events are generated only when we have both: CONFIG_PREEMPT_TRACER && CONFIG_DEBUG_PREEMPT
Signed-off-by: Patrick Bellasi <patrick.bellasi@arm.com> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Reviewed-by: Alessio Balsini <alessio.balsini@arm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Joel Fernandes <joelaf@google.com> Cc: Linux-kernel@vger.kernel.org
--- Fix kernel compilation for this configuration: !CONFIG_DEBUG_PREEMPT && CONFIG_PREEMPT_TRACER
To reproduce, e.g. 1. make defconfig 2. add: CONFIG_PREEMPTIRQ_EVENTS=y CONFIG_PREEMPT_TRACER=y 3. make kernel/trace/trace_irqsoff.o
For sake of consistency, this patch adds a default empty definition of all the new trace events whenever CONFIG_PREEMPTIRQ_EVENTS is enabled but the specific event's requirements are not satisfied. This is complementary to the default empty definitions provided for the !CONFIG_PREEMPTIRQ_EVENTS case. --- include/trace/events/preemptirq.h | 10 ++++++++++ kernel/trace/trace_irqsoff.c | 3 +-- 2 files changed, 11 insertions(+), 2 deletions(-)
diff --git a/include/trace/events/preemptirq.h b/include/trace/events/preemptirq.h index f5024c560d8f..500ad0a221d5 100644 --- a/include/trace/events/preemptirq.h +++ b/include/trace/events/preemptirq.h @@ -40,6 +40,11 @@ DEFINE_EVENT(preemptirq_template, irq_disable, DEFINE_EVENT(preemptirq_template, irq_enable, TP_PROTO(unsigned long ip, unsigned long parent_ip), TP_ARGS(ip, parent_ip)); +#else +#define trace_irq_disable(...) +#define trace_irq_enable(...) +#define trace_irq_disable_rcuidle(...) +#define trace_irq_enable_rcuidle(...) #endif #ifdef CONFIG_DEBUG_PREEMPT @@ -50,6 +55,11 @@ DEFINE_EVENT(preemptirq_template, preempt_disable, DEFINE_EVENT(preemptirq_template, preempt_enable, TP_PROTO(unsigned long ip, unsigned long parent_ip), TP_ARGS(ip, parent_ip)); +#else +#define trace_preempt_disable(...) +#define trace_preempt_enable(...) +#define trace_preempt_disable_rcuidle(...) +#define trace_preempt_enable_rcuidle(...) #endif #endif /* _TRACE_PREEMPTIRQ_H */ diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c index 03ecb4465ee4..9d62e5f30d58 100644 --- a/kernel/trace/trace_irqsoff.c +++ b/kernel/trace/trace_irqsoff.c @@ -848,8 +848,7 @@ inline void print_irqtrace_events(struct task_struct *curr) } #endif -#if defined(CONFIG_PREEMPT_TRACER) || \ - (defined(CONFIG_DEBUG_PREEMPT) && defined(CONFIG_PREEMPTIRQ_EVENTS)) +#ifdef CONFIG_PREEMPT_TRACER void trace_preempt_on(unsigned long a0, unsigned long a1) { trace_preempt_enable_rcuidle(a0, a1); -- 2.14.1
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