From 3ea2e6d71aafe35b8aaf89ed711a283815acfae6 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Sat, 4 Oct 2008 02:01:00 -0400 Subject: ftrace: make some tracers reentrant 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 Signed-off-by: Ingo Molnar --- kernel/trace/trace_sched_switch.c | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-) (limited to 'kernel/trace/trace_sched_switch.c') diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c index c7fa08a5b7f4..b8f56beb1a62 100644 --- a/kernel/trace/trace_sched_switch.c +++ b/kernel/trace/trace_sched_switch.c @@ -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); } -- cgit v1.2.3-59-g8ed1b