Merge branch 'tracing-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'tracing-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (44 commits)
  vsnprintf: remove duplicate comment of vsnprintf
  softirq: add BLOCK_IOPOLL to softirq_to_name
  oprofile: fix oprofile regression: select RING_BUFFER_ALLOW_SWAP
  tracing: switch function prints from %pf to %ps
  vsprintf: add %ps that is the same as %pS but is like %pf
  tracing: Fix minor bugs for __unregister_ftrace_function_probe
  tracing: remove notrace from __kprobes annotation
  tracing: optimize global_trace_clock cachelines
  MAINTAINERS: Update tracing tree details
  ftrace: document function and function graph implementation
  tracing: make testing syscall events a separate configuration
  tracing: remove some unused macros
  ftrace: add compile-time check on F_printk()
  tracing: fix F_printk() typos
  tracing: have TRACE_EVENT macro use __flags to not shadow parameter
  tracing: add static to generated TRACE_EVENT functions
  ring-buffer: typecast cmpxchg to fix PowerPC warning
  tracing: add filter event logic to special, mmiotrace and boot tracers
  tracing: remove trace_event_types.h
  tracing: use the new trace_entries.h to create format files
  ...

1 files changed, 4 insertions, 12 deletions

diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index 5555b75a0d1..3aa7eaa2114 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -129,15 +129,10 @@ check_critical_timing(struct trace_array *tr,
 		      unsigned long parent_ip,
 		      int cpu)
 {
-	unsigned long latency, t0, t1;
 	cycle_t T0, T1, delta;
 	unsigned long flags;
 	int pc;
 
-	/*
-	 * usecs conversion is slow so we try to delay the conversion
-	 * as long as possible:
-	 */
 	T0 = data->preempt_timestamp;
 	T1 = ftrace_now(cpu);
 	delta = T1-T0;
@@ -157,18 +152,15 @@ check_critical_timing(struct trace_array *tr,
 
 	trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
 
-	latency = nsecs_to_usecs(delta);
-
 	if (data->critical_sequence != max_sequence)
 		goto out_unlock;
 
-	tracing_max_latency = delta;
-	t0 = nsecs_to_usecs(T0);
-	t1 = nsecs_to_usecs(T1);
-
 	data->critical_end = parent_ip;
 
-	update_max_tr_single(tr, current, cpu);
+	if (likely(!is_tracing_stopped())) {
+		tracing_max_latency = delta;
+		update_max_tr_single(tr, current, cpu);
+	}
 
 	max_sequence++;