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tracing: make sched_switch stop/start light weight

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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 <srostedt@redhat.com>
This commit is contained in:
Steven Rostedt 2009-03-17 19:59:53 -04:00
parent 97e7e4f391
commit 5fec6ddcb4
1 changed files with 5 additions and 4 deletions
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9
kernel/trace/trace_sched_switch.c
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@ -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 =