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authorSteven Rostedt (VMware) <rostedt@goodmis.org>2017-04-06 15:47:32 -0400
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2017-04-10 15:21:47 -0400
commit8aaf1ee70e19ac74cbbb81098edfa328d1ab4bd7 (patch)
tree5b0e3a0691a6a655b9d25b1812535344ccd6b08d /kernel/trace/trace_stack.c
parent5367278cb7ba74537bcad1470d75f30d95b09c14 (diff)
downloadlinux-8aaf1ee70e19ac74cbbb81098edfa328d1ab4bd7.tar.bz2
tracing: Rename trace_active to disable_stack_tracer and inline its modification
In order to eliminate a function call, make "trace_active" into "disable_stack_tracer" and convert stack_tracer_disable() and friends into static inline functions. Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace_stack.c')
-rw-r--r--kernel/trace/trace_stack.c50
1 files changed, 9 insertions, 41 deletions
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index 21e536cf66e4..f2f02ff350d4 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -35,44 +35,12 @@ unsigned long stack_trace_max_size;
arch_spinlock_t stack_trace_max_lock =
(arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
-static DEFINE_PER_CPU(int, trace_active);
+DEFINE_PER_CPU(int, disable_stack_tracer);
static DEFINE_MUTEX(stack_sysctl_mutex);
int stack_tracer_enabled;
static int last_stack_tracer_enabled;
-/**
- * stack_tracer_disable - temporarily disable the stack tracer
- *
- * There's a few locations (namely in RCU) where stack tracing
- * cannot be executed. This function is used to disable stack
- * tracing during those critical sections.
- *
- * This function must be called with preemption or interrupts
- * disabled and stack_tracer_enable() must be called shortly after
- * while preemption or interrupts are still disabled.
- */
-void stack_tracer_disable(void)
-{
- /* Preemption or interupts must be disabled */
- if (IS_ENABLED(CONFIG_PREEMPT_DEBUG))
- WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
- this_cpu_inc(trace_active);
-}
-
-/**
- * stack_tracer_enable - re-enable the stack tracer
- *
- * After stack_tracer_disable() is called, stack_tracer_enable()
- * must be called shortly afterward.
- */
-void stack_tracer_enable(void)
-{
- if (IS_ENABLED(CONFIG_PREEMPT_DEBUG))
- WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
- this_cpu_dec(trace_active);
-}
-
void stack_trace_print(void)
{
long i;
@@ -243,8 +211,8 @@ stack_trace_call(unsigned long ip, unsigned long parent_ip,
preempt_disable_notrace();
/* no atomic needed, we only modify this variable by this cpu */
- __this_cpu_inc(trace_active);
- if (__this_cpu_read(trace_active) != 1)
+ __this_cpu_inc(disable_stack_tracer);
+ if (__this_cpu_read(disable_stack_tracer) != 1)
goto out;
ip += MCOUNT_INSN_SIZE;
@@ -252,7 +220,7 @@ stack_trace_call(unsigned long ip, unsigned long parent_ip,
check_stack(ip, &stack);
out:
- __this_cpu_dec(trace_active);
+ __this_cpu_dec(disable_stack_tracer);
/* prevent recursion in schedule */
preempt_enable_notrace();
}
@@ -294,15 +262,15 @@ stack_max_size_write(struct file *filp, const char __user *ubuf,
/*
* In case we trace inside arch_spin_lock() or after (NMI),
* we will cause circular lock, so we also need to increase
- * the percpu trace_active here.
+ * the percpu disable_stack_tracer here.
*/
- __this_cpu_inc(trace_active);
+ __this_cpu_inc(disable_stack_tracer);
arch_spin_lock(&stack_trace_max_lock);
*ptr = val;
arch_spin_unlock(&stack_trace_max_lock);
- __this_cpu_dec(trace_active);
+ __this_cpu_dec(disable_stack_tracer);
local_irq_restore(flags);
return count;
@@ -338,7 +306,7 @@ static void *t_start(struct seq_file *m, loff_t *pos)
{
local_irq_disable();
- __this_cpu_inc(trace_active);
+ __this_cpu_inc(disable_stack_tracer);
arch_spin_lock(&stack_trace_max_lock);
@@ -352,7 +320,7 @@ static void t_stop(struct seq_file *m, void *p)
{
arch_spin_unlock(&stack_trace_max_lock);
- __this_cpu_dec(trace_active);
+ __this_cpu_dec(disable_stack_tracer);
local_irq_enable();
}