lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

ftrace: make some tracers reentrant

Browse Source 
Now that the ring buffer is reentrant, some of the ftrace tracers
(sched_swich, debugging traces) can also be reentrant.

Note: Never make the function tracer reentrant, that can cause
  recursion problems all over the kernel. The function tracer
  must disable reentrancy.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Steven Rostedt
2008-10-04 02:01:00 -04:00
committed by Ingo Molnar
parent bf41a158ca
commit 3ea2e6d71a
2 changed files with 4 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
kernel/trace/trace_sched_switch.c
View File

@ -24,7 +24,6 @@ probe_sched_switch(struct rq *__rq, struct task_struct *prev,
{
struct trace_array_cpu *data;
unsigned long flags;
long disabled;
int cpu;
int pc;
@ -41,12 +40,10 @@ probe_sched_switch(struct rq *__rq, struct task_struct *prev,
local_irq_save(flags);
cpu = raw_smp_processor_id();
data = ctx_trace->data[cpu];
disabled = atomic_inc_return(&data->disabled);
if (likely(disabled == 1))
if (likely(!atomic_read(&data->disabled)))
tracing_sched_switch_trace(ctx_trace, data, prev, next, flags, pc);
atomic_dec(&data->disabled);
local_irq_restore(flags);
}
@ -55,7 +52,6 @@ probe_sched_wakeup(struct rq *__rq, struct task_struct *wakee)
{
struct trace_array_cpu *data;
unsigned long flags;
long disabled;
int cpu, pc;
if (!likely(tracer_enabled))
@ -67,13 +63,11 @@ probe_sched_wakeup(struct rq *__rq, struct task_struct *wakee)
local_irq_save(flags);
cpu = raw_smp_processor_id();
data = ctx_trace->data[cpu];
disabled = atomic_inc_return(&data->disabled);
if (likely(disabled == 1))
if (likely(!atomic_read(&data->disabled)))
tracing_sched_wakeup_trace(ctx_trace, data, wakee, current,
flags, pc);
atomic_dec(&data->disabled);
local_irq_restore(flags);
}