diff options
| author | Steven Rostedt <srostedt@redhat.com> | 2008-05-12 19:20:44 (GMT) |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2008-05-23 18:40:15 (GMT) |
| commit | 89b2f97819dd074297bbe3e19eaa4afcc98845ad (patch) | |
| tree | 250196b493d42ac312b089f8f75866518cc772e6 /kernel/trace/trace_irqsoff.c | |
| parent | 18cef379d30f5ded20cc31d7f2d342639d39919d (diff) | |
| download | linux-89b2f97819dd074297bbe3e19eaa4afcc98845ad.tar.xz | |
ftrace: fix updates to max trace
This patch fixes some bugs to the updating of the max trace that
was caused by implementing the new buffering.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/trace/trace_irqsoff.c')
| -rw-r--r-- | kernel/trace/trace_irqsoff.c | 27 |
1 files changed, 15 insertions, 12 deletions
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c index bd3f881..74165f6 100644 --- a/kernel/trace/trace_irqsoff.c +++ b/kernel/trace/trace_irqsoff.c @@ -23,6 +23,8 @@ static int tracer_enabled __read_mostly; static DEFINE_PER_CPU(int, tracing_cpu); +static DEFINE_SPINLOCK(max_trace_lock); + enum { TRACER_IRQS_OFF = (1 << 1), TRACER_PREEMPT_OFF = (1 << 2), @@ -126,7 +128,7 @@ check_critical_timing(struct trace_array *tr, int cpu) { unsigned long latency, t0, t1; - cycle_t T0, T1, T2, delta; + cycle_t T0, T1, delta; unsigned long flags; /* @@ -142,20 +144,18 @@ check_critical_timing(struct trace_array *tr, if (!report_latency(delta)) goto out; - ftrace(tr, data, CALLER_ADDR0, parent_ip, flags); - /* - * Update the timestamp, because the trace entry above - * might change it (it can only get larger so the latency - * is fair to be reported): - */ - T2 = now(cpu); + spin_lock(&max_trace_lock); - delta = T2-T0; + /* check if we are still the max latency */ + if (!report_latency(delta)) + goto out_unlock; + + ftrace(tr, data, CALLER_ADDR0, parent_ip, flags); latency = nsecs_to_usecs(delta); if (data->critical_sequence != max_sequence) - goto out; + goto out_unlock; tracing_max_latency = delta; t0 = nsecs_to_usecs(T0); @@ -189,6 +189,9 @@ check_critical_timing(struct trace_array *tr, max_sequence++; +out_unlock: + spin_unlock(&max_trace_lock); + out: data->critical_sequence = max_sequence; data->preempt_timestamp = now(cpu); @@ -366,14 +369,14 @@ void notrace trace_preempt_off(unsigned long a0, unsigned long a1) static void start_irqsoff_tracer(struct trace_array *tr) { - tracer_enabled = 1; register_ftrace_function(&trace_ops); + tracer_enabled = 1; } static void stop_irqsoff_tracer(struct trace_array *tr) { - unregister_ftrace_function(&trace_ops); tracer_enabled = 0; + unregister_ftrace_function(&trace_ops); } static void __irqsoff_tracer_init(struct trace_array *tr) |