In order to use ftrace tracers to generate tracepoints without doing tracing to its own hardcoded ring buffers, add a ftrace-buffer option (default: 1). When set to 0, it disables tracing into the ftrace hardcoded buffers.
Signed-off-by: Mathieu Desnoyers <[email protected]> CC: Thomas Gleixner <[email protected]> CC: Steven Rostedt <[email protected]> CC: Ingo Molnar <[email protected]> CC: Peter Zijlstra <[email protected]> --- kernel/trace/trace.c | 4 +++- kernel/trace/trace.h | 1 + kernel/trace/trace_irqsoff.c | 19 +++++++++++-------- 3 files changed, 15 insertions(+), 9 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 6e79408..d664f0e 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -472,7 +472,8 @@ static inline void trace_access_lock_init(void) unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK | TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | TRACE_ITER_SLEEP_TIME | TRACE_ITER_GRAPH_TIME | TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE | - TRACE_ITER_IRQ_INFO | TRACE_ITER_MARKERS | TRACE_ITER_FUNCTION; + TRACE_ITER_IRQ_INFO | TRACE_ITER_MARKERS | TRACE_ITER_FUNCTION | + TRACE_ITER_FTRACE_BUFFER; static void tracer_tracing_on(struct trace_array *tr) { @@ -862,6 +863,7 @@ static const char *trace_options[] = { "irq-info", "markers", "function-trace", + "ftrace-buffer", NULL }; diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 74bde81..29968e1 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -930,6 +930,7 @@ enum trace_iterator_flags { TRACE_ITER_IRQ_INFO = 0x800000, TRACE_ITER_MARKERS = 0x1000000, TRACE_ITER_FUNCTION = 0x2000000, + TRACE_ITER_FTRACE_BUFFER = 0x4000000, }; /* diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c index 8523ea3..3e5635d 100644 --- a/kernel/trace/trace_irqsoff.c +++ b/kernel/trace/trace_irqsoff.c @@ -334,9 +334,11 @@ check_critical_timing(struct trace_array *tr, if (!report_latency(tr, delta)) goto out_unlock; - __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc); - /* Skip 5 functions to get to the irq/preempt enable function */ - __trace_stack(tr, flags, 5, pc); + if (trace_flags & TRACE_ITER_FTRACE_BUFFER) { + __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc); + /* Skip 5 functions to get to the irq/preempt enable function */ + __trace_stack(tr, flags, 5, pc); + } if (data->critical_sequence != max_sequence) goto out_unlock; @@ -356,7 +358,8 @@ out_unlock: out: data->critical_sequence = max_sequence; data->preempt_timestamp = ftrace_now(cpu); - __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc); + if (trace_flags & TRACE_ITER_FTRACE_BUFFER) + __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc); } static inline void @@ -387,9 +390,8 @@ start_critical_timing(unsigned long ip, unsigned long parent_ip) data->critical_start = parent_ip ? : ip; local_save_flags(flags); - - __trace_function(tr, ip, parent_ip, flags, preempt_count()); - + if (trace_flags & TRACE_ITER_FTRACE_BUFFER) + __trace_function(tr, ip, parent_ip, flags, preempt_count()); per_cpu(tracing_cpu, cpu) = 1; atomic_dec(&data->disabled); @@ -422,7 +424,8 @@ stop_critical_timing(unsigned long ip, unsigned long parent_ip) atomic_inc(&data->disabled); local_save_flags(flags); - __trace_function(tr, ip, parent_ip, flags, preempt_count()); + if (trace_flags & TRACE_ITER_FTRACE_BUFFER) + __trace_function(tr, ip, parent_ip, flags, preempt_count()); check_critical_timing(tr, data, parent_ip ? : ip, cpu); data->critical_start = 0; atomic_dec(&data->disabled); -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
