From 5fec6ddcb43a91aa9a254c8ecf174c803de6f07e Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Tue, 17 Mar 2009 19:59:53 -0400 Subject: [PATCH] tracing: make sched_switch stop/start light weight The stopping and starting of a tracer should be light weight and be able to be called in all contexts. The sched_switch grabbed mutexes in the start/stop functions. This patch changes it to a simple variable, on/off. Signed-off-by: Steven Rostedt --- kernel/trace/trace_sched_switch.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c index 77132c2cf3d9..de35f200abd3 100644 --- a/kernel/trace/trace_sched_switch.c +++ b/kernel/trace/trace_sched_switch.c @@ -18,6 +18,7 @@ static struct trace_array *ctx_trace; static int __read_mostly tracer_enabled; static int sched_ref; static DEFINE_MUTEX(sched_register_mutex); +static int sched_stopped; static void probe_sched_switch(struct rq *__rq, struct task_struct *prev, @@ -28,7 +29,7 @@ probe_sched_switch(struct rq *__rq, struct task_struct *prev, int cpu; int pc; - if (!sched_ref) + if (!sched_ref || sched_stopped) return; tracing_record_cmdline(prev); @@ -193,6 +194,7 @@ static void stop_sched_trace(struct trace_array *tr) static int sched_switch_trace_init(struct trace_array *tr) { ctx_trace = tr; + tracing_reset_online_cpus(tr); tracing_start_sched_switch_record(); return 0; } @@ -205,13 +207,12 @@ static void sched_switch_trace_reset(struct trace_array *tr) static void sched_switch_trace_start(struct trace_array *tr) { - tracing_reset_online_cpus(tr); - tracing_start_sched_switch(); + sched_stopped = 0; } static void sched_switch_trace_stop(struct trace_array *tr) { - tracing_stop_sched_switch(); + sched_stopped = 1; } static struct tracer sched_switch_trace __read_mostly =